AIM: To study the core cell damage in isolated islets of Langerhans and its prevention by low temperature preconditioning (26 ℃).METHODS: Islets were cultured at 37 ℃ for 7-14 d after isolation, and then at 26 ℃ fo...AIM: To study the core cell damage in isolated islets of Langerhans and its prevention by low temperature preconditioning (26 ℃).METHODS: Islets were cultured at 37 ℃ for 7-14 d after isolation, and then at 26 ℃ for 2, 4 and 7 d before additional culture at 37 ℃ for another 7 d. Core cell damage in the isolated islets was monitored by video-microscopy and analyzed quantitatively by use of a computer-assisted image analysis system. The analysis included daily measurement of the diameter and the area of the isolated islets and the area of the core cell damage that developed in those islets over time during culture. Histology and TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay were used to characterize the cell damage and to monitor islet function.RESULTS: Microscopic analysis showed that during the 7 to 14 d of culture at 37 ℃, core cell damage occurred in the larger islets with diameters >200 μm, which included both necrotic and apoptotic cell death. Low temperature (26 ℃) culture could prevent core cell damage of isolated islets. The 7-d culture procedure at 26 ℃ could inhibit most of the core cell (excluding diameters>300 μm) damages when the islets were re-warmed at 37 ℃.CONCLUSION: Our results indicate that core cell damage within isolated islets of Langerhans correlates with the size of islets. Low temperature (26 ℃) culture can prevent core cell damage in isolated islets, and successfully precondition these islets for incubation at 37 ℃. These novel findings may help to understand the pathophysiology of early loss of islet tissue after transplantation, and may provide a new strategy to improve graft function in the clinical setting of islet transplantation.展开更多
BACKGROUND: The efficacy of clinical islet transplanta- tion has been demonstrated with autografts, and although islet allografts have established insulin independence in a small number of IDDM patients, the treatment...BACKGROUND: The efficacy of clinical islet transplanta- tion has been demonstrated with autografts, and although islet allografts have established insulin independence in a small number of IDDM patients, the treatment is con- founded by the necessity of central cell damage immuno- suppression, the lack of donor tissue, and recurring islet immunogenicity. These limitations underscore a need to develop therapies to serve the large population of diabetic patients. This study was designed to document central cell damage to isolated islets of Langerhans in hamsters and its prevention. METHODS: Islets were cultured at 37 °C for 7-14 days after isolation, and then at 26 °C for 2,4 and 7 days before addi- tional culture at 37 °C for an additional 7 days. Central cell damage in the isolated islets was monitored by video-mi- croscopy and analyzed quantitatively by a computer-assis- ted image analysis system. The analysis included daily measurement of the diameter and the area of the isolated is- lets and the area of the central cell damage that developed in those islets over time during culture. Histological exami- nation and TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay were used to characterize cell damage and to monitor islet function. RESULTS; Microscopic analysis showed that during the 7 to 14 days of culture at 37 °C, central cell damage appeared in the larger islets with diameters greater than 200 μm, which included both necrotic and apoptotic cell death. Low temperature (26 °C) culture prevented central cell damage of isolated islets. The 7-day culture procedure at 26 °C could inhibit most of the central cell ( excluding diameters greater than 300 μm) damage when the islets were re- warmed to 37 °C. CONCLUSIONS: Our results indicate that central cell da- mage to isolated islets of Langerhans correlates with the size of the islets. Low temperature (26 °C) culture can preventcentral cell damage to the isolated islets, and is capable to successfully precondition these islets for 37 °C culture. These novel findings may help to understand the patho- physiology of early loss of islet tissue after transplantation, and may provide a new strategy to improve graft function in the clinical setting of islet transplantation.展开更多
Type 1 diabetes mellitus(T1DM) lacks insulin secretion due to autoimmune deficiency of pancreaticβ-cells.Protecting pancreatic islets and enhancing insulin secretion has been therapeutic approaches.Mannogalactoglucan...Type 1 diabetes mellitus(T1DM) lacks insulin secretion due to autoimmune deficiency of pancreaticβ-cells.Protecting pancreatic islets and enhancing insulin secretion has been therapeutic approaches.Mannogalactoglucan is the main type of polysaccharide from natural mushroom,which has potential medicinal prospects.Nevertheless,the antidiabetic property of mannogalactoglucan in T1DM has not been fully elucidated.In this study,we obtained the neutral fraction of alkali-soluble Armillaria mellea polysaccharide(AAMP-N) with the structure of mannogalactoglucan from the fruiting body of A.mellea and investigated the potential therapeutic value of AAMP-N in T1DM.We demonstrated that AAMP-N lowered blood glucose and improved diabetes symptoms in T1DM mice.AAMP-N activated unfolded protein response(UPR) signaling pathway to maintain ER protein folding homeostasis and promote insulin secretion in vivo.Besides that,AAMP-N promoted insulin synthesis via upregulating the expression of transcription factors,increased Ca^(2+) signals to stimulate intracellular insulin secretory vesicle transport via activating calcium/calmodulin-dependent kinase Ⅱ(CamkⅡ) and cAMP/PKA signals,and enhanced insulin secretory vesicle fusion with the plasma membrane via vesicle-associated membrane protein 2(VAMP2).Collectively,these studies demonstrated that the therapeutic potential of AAMP-N on pancreatic islets function,indicating that mannogalactoglucan could be natural nutraceutical used for the treatment of T1DM.展开更多
BACKGROUND Langerhans cell histiocytosis(LCH)is a histiocytic proliferative disease caused by clonal proliferation of Langerhans cells,which is currently defined as an inflam-matory myeloid tumor.It is rare in adults,...BACKGROUND Langerhans cell histiocytosis(LCH)is a histiocytic proliferative disease caused by clonal proliferation of Langerhans cells,which is currently defined as an inflam-matory myeloid tumor.It is rare in adults,with an incidence of 1–2 per million,and is highly heterogeneous in clinical presentation,with unpredictable disease progression and outcome.CASE SUMMARY A 52-year-old postmenopausal female patient presented to the gynecology department in July 2023 with bilateral vulvar masses.She was diagnosed with recurrent multisystem LCH.The patient had previously been diagnosed with a single-system and single-focal LCH in October 2021 due to a right maxillofacial mass,which resolved after surgical treatment.A chemotherapy regimen was developed after multidisciplinary consultation.Six cycles of chemotherapy resulted in partial remission,and maintenance chemotherapy is currently being administered.CONCLUSION Recurrent LCH involving the bilateral vulva has been poorly reported.Compre-hensive imaging and pathological evaluation is important for diagnosis.The model of joint multidisciplinary specialist diagnosis and treatment is worthy of clinical application.展开更多
BACKGROUND Langerhans cell histiocytosis(LCH)is characterized by diabetes insipidus and is an uncommon occurrence.Pathological biopsies still have a certain degree of diagnostic probability.We present a case in which ...BACKGROUND Langerhans cell histiocytosis(LCH)is characterized by diabetes insipidus and is an uncommon occurrence.Pathological biopsies still have a certain degree of diagnostic probability.We present a case in which LCH initially affected the pituitary gland.This resulted in a misdiagnosis of chronic inflammation upon pathological examination.CASE SUMMARY A 25-year-old female exhibited symptoms of diabetes insipidus.Magnetic resonance imaging revealed an enhanced foci in the pituitary gland.After surgical resection of the pituitary lesion,the pathological diagnosis was chronic inflam-mation.However,the patient later experienced bone destruction in the skull and lower limb bones.After the lower limb bone lesion was compared with the initial pituitary lesion,the final diagnosis was modified to LCH.The patient was treated with multiple chemotherapy courses.However,the patient’s condition gradually worsened,and she eventually passed away at home.CONCLUSION LCH should be considered when patients exhibit diabetes insipidus and absence of high signal intensity in the pituitary gland on sagittal T1-weighted image and abnormal enhancement in the pituitary region.展开更多
Erdheim-Chester Disease (ECD) is a rare condition and has various differential diagnoses with other forms of histiocytosis, classified as one of non-Langerhans histiocytosis. The diagnosis of this condition remains ch...Erdheim-Chester Disease (ECD) is a rare condition and has various differential diagnoses with other forms of histiocytosis, classified as one of non-Langerhans histiocytosis. The diagnosis of this condition remains challenging because its presentation includes non-specific systemic manifestations that can affect different organs caused by deposition of lipids and fibrosis. Most common include bone pain followed by progressive weakness and different lung manifestations. This case is about a rare presentation of ECD with Langerhans Histiocytosis as overlap syndrome, with findings of both diseases in a middle aged woman that presented dyspnea as the first symptom. The patient was treated initially as heart failure and remained without any improvement, being admitted to investigate. After a stricted follow-up, bone and lung involvement were noticed and a skin biopsy unveiled xanthomatized macrophages accompanied by Touton giant cells. This condition remains an important clinical entity and should provide new insights for clinicians dealing with respiratory diseases.展开更多
BACKGROUND Langerhans cell histiocytosis(LCH)is a rare clonal proliferative disease of Langerhans cells with unknown pathogenesis.An increasing number of clinicians recognize that LCH has a wide clinical spectrum and ...BACKGROUND Langerhans cell histiocytosis(LCH)is a rare clonal proliferative disease of Langerhans cells with unknown pathogenesis.An increasing number of clinicians recognize that LCH has a wide clinical spectrum and a highly varied course.Adults rarely develop LCH.Here,we report a case of adult localized LCH.CASE SUMMARY A 32-year-old woman presented with plaques and ulcers on the vulva and crissum,accompanied by pain that persisted for more than one year.Physical examination revealed a red-infiltrating plaque with ulcerations and exudates in the vulva and crissum.Pathological examination revealed a diffuse infiltration of lymphocytes,eosinophilic granulocytes,and histiocytoid cells in the superficial dermis.Proliferative histiocytoid cells showed mild atypia,partly with kidneyshaped nuclei.Immunohistochemical examination showed that the histiocytoid cells were positive for S100 protein and CD1 and weakly positive for CD68(20%+),with a Ki-67 index of 30%.Laboratory tests did not reveal any other systemic damage.The patient was diagnosed with adult localized LCH and was prescribed oral prednisone(20 mg)once daily.The skin lesions gradually improved and are still being followed-up.CONCLUSION Adult localized LCH is rare and must be differentiated from other common conditions.展开更多
AIM: To establish a model of islet-ductal cell transdifferen-tiation to identify the transdifferentiated cells. METHODS: Collagen was extracted from rat tail at first. Purified rat islets were divided into three group...AIM: To establish a model of islet-ductal cell transdifferen-tiation to identify the transdifferentiated cells. METHODS: Collagen was extracted from rat tail at first. Purified rat islets were divided into three groups, embedded in collagen gel and incubated respectively in DMEM/F12 alone (control group), DMEM/F12 plus epidermal growth factor (EGF), DMEM/F12 plus EGF and cholera toxin (CT). Transdifferentiation was proved by microscopy, RT-PCR, immunohistochemistry and RIA. RESULTS: Islets embedded in collagen gel plus EGF and CT were cystically transformed and could express new gene cytokeratin 19 while still maintaining the expression of insulin and Pdx-1 genes. Immunohistochemistry demonstrated that the protein of cytokeratin 19 was only expressed in the third group. The insulin content secreted by islets in the third group decreased significantly during the transdiffe-rentiation. CONCLUSION: CT is a crucial factor for the islet-ductal cell transdifferentiation.展开更多
AIM: To identify the decreasing effect of xenotransplantion in combination with privileged sites on rejection and death of biological semipermeable membrane-(BSM) encapsulated implanted islets. METHODS: After the ...AIM: To identify the decreasing effect of xenotransplantion in combination with privileged sites on rejection and death of biological semipermeable membrane-(BSM) encapsulated implanted islets. METHODS: After the BSM experiment in vitro, BSM- encapsulated SD rat's islet-like cell clusters (ICCs) were xenotransplanted into normal dog's brain. Morphological changes were observed under light and transmission electron microscope. The islets and apoptosis of implanted B cells were identified by insulin-TONEL double staining. RESULTS: The BSM used in our study had a favorable permeability, some degree of rigidity, lighter foreign body reaction and toxicity. The grafts consisted of epithelioid cells and loose connective tissue. Severe infiltration of inflammatory cells was not observed. The implanted ICCs were identified 2 mo later and showed typical apoptosis. CONCLUSION: BSM xenotransplantation in combination with the privileged site can inhibit the rejection of implanted heterogeneous ICCs, and death of implanted heterogeneous B cells is associated with apoptosis. 2005 The WJG Press and Elsevier Inc. All rights reserved.展开更多
The pancreas became one of the first objects of regenerative medicine,since other possibilities of dealing with the pancreatic endocrine insufficiency were clearly exhausted.The number of people living with diabetes m...The pancreas became one of the first objects of regenerative medicine,since other possibilities of dealing with the pancreatic endocrine insufficiency were clearly exhausted.The number of people living with diabetes mellitus is currently approaching half a billion,hence the crucial relevance of new methods to stimulate regeneration of the insulin-secretingβ-cells of the islets of Langerhans.Natural restrictions on the islet regeneration are very tight;nevertheless,the islets are capable of physiological regeneration viaβ-cell self-replication,direct differentiation of multipotent progenitor cells and spontaneousα-toβ-orδ-toβ-cell conversion(trans-differentiation).The existing preclinical models ofβ-cell dysfunction or ablation(induced surgically,chemically or genetically)have significantly expanded our understanding of reparative regeneration of the islets and possible ways of its stimulation.The ultimate goal,sufficient level of functional activity ofβ-cells or their substitutes can be achieved by two prospective broad strategies:β-cell replacement andβ-cell regeneration.The“regeneration”strategy aims to maintain a preserved population ofβ-cells through in situ exposure to biologically active substances that improveβ-cell survival,replication and insulin secretion,or to evoke the intrinsic adaptive mechanisms triggering the spontaneous non-β-toβ-cell conversion.The“replacement”strategy implies transplantation ofβ-cells(as non-disintegrated pancreatic material or isolated donor islets)orβ-like cells obtained ex vivo from progenitors or mature somatic cells(for example,hepatocytes orα-cells)under the action of small-molecule inducers or by genetic modification.We believe that the huge volume of experimental and clinical studies will finally allow a safe and effective solution to a seemingly simple goal-restoration of the functionally activeβ-cells,the innermost hope of millions of people globally.展开更多
Although allogeneic islet transplantation can successfully cure type 1 diabetes,it has limited applicability.For example,organs are in short supply;several human pancreas donors are often needed to treat one diabetic ...Although allogeneic islet transplantation can successfully cure type 1 diabetes,it has limited applicability.For example,organs are in short supply;several human pancreas donors are often needed to treat one diabetic recipient;the intrahepatic site may not be the most appropriate site for islet implantation;and immunosuppressive regimens,which are associated with side effects,are often required to prolong survival of the islet graft.An alternative source of insulinproducing cells would therefore be of major interest.Pigs represent a possible alternative source of beta cells.Grafting of pig islets may appear difficult because of the immunologic species barrier,but pig islets have been shown to function in primates for at least 6 mo with clinically incompatible immunosuppression.Therefore,a bioartificial pancreas made of encapsulated pig islets may resolve issues associated with islet allotransplantation.Although several groups have shown that encapsulated pig islets are functional in small-animal models,less is known about the use of bioartificial pancreases in large-animal models.In this review,we summarize current knowledge of encapsulated pig islets,to determine obstacles to implantation in humans and possible solutions to overcome these obstacles.展开更多
At present, proven clinical treatments but no cures are available for diabetes, a global epidemic with a huge economic burden. Transplantation of islets ofLangerhans by their infusion into vascularized organs is an ex...At present, proven clinical treatments but no cures are available for diabetes, a global epidemic with a huge economic burden. Transplantation of islets ofLangerhans by their infusion into vascularized organs is an experimental clinical protocol, the first approach to attain cure. However, it is associated with lifelong use of immunosuppressants. To overcome the need for immunosuppression, islets are encapsulated and separated from the host immune system by a permselective membrane. The lead material for this application is alginate which was tested in many animal models and a few clinical trials. This review discusses all aspects related to the function of transplanted encapsulated islets such as the basic requirements from a permselective membrane(e.g., allowable hydrodynamic radii, implications of the thickness of the membrane and relative electrical charge). Another aspect involves adequate oxygen supply, which is essential for survival/performance of transplanted islets, especially when using large retrievable macrocapsules implanted in poorly oxygenated sites like the subcutis. Notably, islets can survive under low oxygen tension and are physiologically active at > 40 Torr. Surprisingly, when densely crowded, islets are fully functional under hyperoxic pressure of up to 500 Torr(> 300% of atmospheric oxygen tension). The review also addresses an additional category of requirements for optimal performance of transplanted islets, named auxiliary technologies. These include control of inflammation, apoptosis, angiogenesis, and the intra-capsular environment. The review highlights that curing diabetes with a functional bio-artificial pancreas requires optimizing all of these aspects, and that significant advances have already been made in many of them.展开更多
Islet transplantation could become an ideal treatment for severe diabetes to prevent hypoglycemia shock and irreversible diabetic complications, once some of the major and unresolved obstacles are overcome, including ...Islet transplantation could become an ideal treatment for severe diabetes to prevent hypoglycemia shock and irreversible diabetic complications, once some of the major and unresolved obstacles are overcome, including limited donor supplies and side effects caused by permanent immunosuppressant use. Approximately 30 years ago, some groups succeeded in improving the blood glucose of diabetic animals by transplanting encapsulated islets with semi-permeable membranes consisting of polymer. A semi-permeable membrane protects both the inner islets from mechanical stress and the recipient’s immune system (both cellular and humoral immunities), while allowing bidirectional diffusion of nutrients, oxygen, glucose, hormones and wastes, i.e., immune-isolation. This device, which enables immune-isolation, is called encapsulated islets or bio-artificial pancreas. Encapsulation with a semipermeable membrane can provide some advantages: (1) this device protects transplanted cells from the recipient’s immunity even if the xenogeneic islets (from large animals such as pig) or insulin-producing cells are derived from cells that have the potential for differentiation (some kinds of stem cells). In other words, the encapsulation technique can resolve the problem of limited donor supplies; and (2) encapsulation can reduce or prevent chronic administration of immunosuppressants and, therefore, important side effects otherwise induced by immunosuppressants. And now, many novel encapsulated islet systems have been developed and are being prepared for testing in a clinical setting.展开更多
AIM: TO explore the effects of fentanyl on insulin release from freshly isolated rat pancreatic islets in static culture. METHODS: Islets were isolated from the pancreas of mature Sprague Dawley rats by common bile ...AIM: TO explore the effects of fentanyl on insulin release from freshly isolated rat pancreatic islets in static culture. METHODS: Islets were isolated from the pancreas of mature Sprague Dawley rats by common bile duct intraductal collagenase V digestion and were purified by discontinuous Ficoll density gradient centrifugation. The islets were divided into four groups according to the fentanyl concentration: control group (0 ng/mL), group I (0.3 ng/mL), group I (3.0 ng/mL), and group III (30 ng/mL). In each group, the islets were co-cultured for 48 h with drugs under static conditions with fentanyl alone, fentanyl + 0.1 μg/mL naloxone or fentanyl + 1.0 μg/mL naloxone. Cell viability was assessed by the MTT assay. Insulin release in response to low and high concentrations (2.8 mmol/L and 16.7 mmol/L, respectively) of glucose was investigated and electron microscopy morphological assessment was performed. RESULTS: Low- and high-glucose-stimulated insulin release in the control group was significantly higher than in groups I and II (62.33 ± 9.67 μIU vs 47.75 ± 8.47 μIU, 39.67 ± 6.18 μIU and 125.5 ± 22.04 μIU vs 96.17 ± 14.17 μIU, 75.17 ± 13.57 μIU, respectively, P 〈 0.01) and was lowest in group III (P 〈 0.01). After adding 1 μg/mL naloxone, insulin release in groups II and II was not different from the control group. Electron microscopy studies showed that the islets were damaged by 30 ng/ml fentanyl. CONCLUSION: Fentanyl inhibited glucose-stimulated insulin release from rat islets, which could be prevented by naloxone. Higher concentrations of fentanyl significantly damaged β-cells of rat islets.展开更多
Because insulin released by the β-cells of pancreatic islets is the main regulator of glucose levels, the quantitative modeling of their glucose-stimulated insulin secretion is of obvious interest not only to improve...Because insulin released by the β-cells of pancreatic islets is the main regulator of glucose levels, the quantitative modeling of their glucose-stimulated insulin secretion is of obvious interest not only to improve our understanding of the processes involved, but also to allow better assessment of β -cell function in diabetic patients or islet transplant recipients as well as the development of improved artificial or bioartificial pancreas devices. We have recently developed a general, local concentrations-based multiphysics computational model of insulin secretion in avascular pancreatic islets that can be used to calculate insulin secretion for arbitrary geometries of cultured, perifused, transplanted, or encapsulated islets in response to various glucose profiles. Here, experimental results obtained from two different dynamic glucose-stimulated insulin release (GSIR) perifusion studies performed by us following standard procedures are compared to those calculated by the model. Such perifusion studies allow the quantitative assessment of insulin release kinetics under fully controllable experimental conditions of varying external concentrations of glucose, oxygen, or other compounds of interest, and can provide an informative assessment of islet quality and function. The time-profile of the insulin secretion calculated by the model was in good agree- ment with the experimental results obtained with isolated human islets. Detailed spatial distributions of glucose, oxygen, and insulin were calculated and are presented to provide a quantitative visualization of various important aspects of the insulin secretion dynamics in perifused islets.展开更多
Objective: To evaluate the immunoisola ti ng effects of barium-alginate microencapsulation on islets allograft survival. Methods: The nonmicroencapsulated and microencapsulated islets w ere transplanted under the kid...Objective: To evaluate the immunoisola ti ng effects of barium-alginate microencapsulation on islets allograft survival. Methods: The nonmicroencapsulated and microencapsulated islets w ere transplanted under the kidney capsule or intraperitoneally into Wistar rat w ith STZ-induced diabetes. The blood glucose and insulin secretion of grafts wer e observed. Graft function was tested by oral glucose tolerance test (OGTT). Results: ①Five diabetic rats became normoglycemic for 48 to 72 h after microencapsulated islets transplantation. The survival of transplanted i slets was on an average of 6 W. ②The normalization of the glycemia and insulin in the transplanted rats was associated with normal glucose and insulin profiles in response to OGTT. Conclusion: Microencapsulation with barium -alginate membrane can prolong islet survival and protect islets against allore jection.展开更多
Damped wave diffusion effects during oxygen transport in islets of Langerhans is studied. Simultaneous reaction and diffusion models were developed. The asymptotic limits of first and zeroth order in Michaelis and Men...Damped wave diffusion effects during oxygen transport in islets of Langerhans is studied. Simultaneous reaction and diffusion models were developed. The asymptotic limits of first and zeroth order in Michaelis and Menten kinetics was used in the study. Parabolic Fick diffusion and hyperbolic damped wave diffusion were studied separately. Method of relativistic transformation was used in order to obtain the solution for the hyperbolic model. Model solutions was used to obtain mass inertial times. Convective boundary condition was used. Sharma number (mass) may be used in evaluating the importance of the damped wave diffusion process in relation to other processes such as convection, Fick steady diffusion in the given application. Four regimes can be identified in the solution of hyperbolic damped wave diffusion model. These are;1) Zero Transfer Inertial Regime, 0 0≤τ≤τinertia;2) Rising Regime during times greater than inertial regime and less than at the wave front, Xp > τ, 3) at Wave front , τ = Xp;4) Falling Regime in open Interval, of times greater than at the wave front, τ > Xp. Method of superposition of steady state concentration and transient concentration used in both solutions of parabolic and hyperbolic models. Expression for steady state concentration developed. Closed form analytic model solutions developed in asymptotic limits of Michaelis and Menten kinetic at zeroth order and first order. Expression for Penetration Length Derived-Hypoxia Explained. Expression for Inertial Lag Time Derived. Solution was obtained by the method of separation of variables for transient for parabolic model and by the method of relativistic transformation for hyperbolic models. The concentration profile was expressed as a sum of steadty state and transient parts.展开更多
We have previously demonstrated that allogeneic human bone marrow (BM) supports human islet function and longevity in vitro. We hypothesize that BM supporting human islets may include to increase β-cell in cultured i...We have previously demonstrated that allogeneic human bone marrow (BM) supports human islet function and longevity in vitro. We hypothesize that BM supporting human islets may include to increase β-cell in cultured islets. In this study, we developed a method to quantify insulin-producing β cells from cultured islets by using immunofluorescent staining and flow cytometry analysis to explore this possibility. The results show that human islets cocultured with BM for 39 days contained a significantly higher number of insulin-positive β cells (42.3% ± 4.5%) compared to the islet-only cultures (1.15% ± 0.78%), and increased insulin release levels evaluated by ELISA is consistent with increased β cells in same culture condition. Human islet culture with BM significantly increase β-cells while islet only culture lost β-cells in same culture period supports the possibility of BM increasing β-cells in cultured islets.展开更多
Aiming at Delaunay triangulation with islets constrains in terrain simulation. A general Delaunay triangulation algorithm for constrained data set with islets is proposed. The algorithm firstly constructs Constrained ...Aiming at Delaunay triangulation with islets constrains in terrain simulation. A general Delaunay triangulation algorithm for constrained data set with islets is proposed. The algorithm firstly constructs Constrained Delaunay Triangulation with constraint polygons which are inner boundary of islets, then according to topological relations within edge, surface, arc segment, applies bidirectional search to find the triangle in islet, lastly it carries on certain corresponding processing to complete the Delaunay triangulation algorithm with islets. The analyses show the algorithm simple, fast speed. The algorithm can be used in 3-D terrain vision.展开更多
Background and Objective: Islet autotransplantation is performed to preserve endocrine function in patients undergoing pancreatic resections for painful chronic pancreatitis. We characterized islets isolated from chro...Background and Objective: Islet autotransplantation is performed to preserve endocrine function in patients undergoing pancreatic resections for painful chronic pancreatitis. We characterized islets isolated from chronic pancreatitis patients (CP) of tropical region. Patients and Methods: Pancreatic tissues were obtained from CP patients with and without diabetes undergoing pancreatic resections (n = 35) and brain-dead multi organ donors (n = 6;considered as controls). Islets isolated were assessed for yield, purity, viability and in vitro islet function (Glucose stimulated insulin release, GSIR) as per standard protocols. Results: Islets from CP patients without diabetes were similar to controls in yield (control 4120 - 6100 IE/g, CP 3550 - 5660 IE/g), purity (control 78% ± 12%, CP 70% ± 8.2%) and viability (control 85% ± 8%, CP 81% ± 10%) and islets from CP patients with diabetes showed decreases in yield (3002 - 2300 IE/g), purity (61% ± 16%) and viability (62% ± 21%). Islets measuring 50 - 200 μ were similar in abundance in controls (94.74% ± 3.2%) and CP patients with and without diabetes, 86.31% ± 4.9%, 91.03% ± 3.8%. GSIR of islets from CP patients and controls were similar at 5.5 mM glucose (2.8 - 3.1 μU/ml). However, GSIR at 16.5 mM glucose was decreased in CP patients (control 18.5 ± 0.6, CP without diabetes 11.8 ± 0.3, CP with diabetes 4.3 ± 0.3 μU/ml). Conclusion: Our results demonstrate suitability of islets isolated from CP patients of tropical region for autotransplantation.展开更多
基金Supported by the National Natural Science Foundation of China, No.30271274 German DAAD-Wong Kuan Cheng Fellowship
文摘AIM: To study the core cell damage in isolated islets of Langerhans and its prevention by low temperature preconditioning (26 ℃).METHODS: Islets were cultured at 37 ℃ for 7-14 d after isolation, and then at 26 ℃ for 2, 4 and 7 d before additional culture at 37 ℃ for another 7 d. Core cell damage in the isolated islets was monitored by video-microscopy and analyzed quantitatively by use of a computer-assisted image analysis system. The analysis included daily measurement of the diameter and the area of the isolated islets and the area of the core cell damage that developed in those islets over time during culture. Histology and TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay were used to characterize the cell damage and to monitor islet function.RESULTS: Microscopic analysis showed that during the 7 to 14 d of culture at 37 ℃, core cell damage occurred in the larger islets with diameters >200 μm, which included both necrotic and apoptotic cell death. Low temperature (26 ℃) culture could prevent core cell damage of isolated islets. The 7-d culture procedure at 26 ℃ could inhibit most of the core cell (excluding diameters>300 μm) damages when the islets were re-warmed at 37 ℃.CONCLUSION: Our results indicate that core cell damage within isolated islets of Langerhans correlates with the size of islets. Low temperature (26 ℃) culture can prevent core cell damage in isolated islets, and successfully precondition these islets for incubation at 37 ℃. These novel findings may help to understand the pathophysiology of early loss of islet tissue after transplantation, and may provide a new strategy to improve graft function in the clinical setting of islet transplantation.
文摘BACKGROUND: The efficacy of clinical islet transplanta- tion has been demonstrated with autografts, and although islet allografts have established insulin independence in a small number of IDDM patients, the treatment is con- founded by the necessity of central cell damage immuno- suppression, the lack of donor tissue, and recurring islet immunogenicity. These limitations underscore a need to develop therapies to serve the large population of diabetic patients. This study was designed to document central cell damage to isolated islets of Langerhans in hamsters and its prevention. METHODS: Islets were cultured at 37 °C for 7-14 days after isolation, and then at 26 °C for 2,4 and 7 days before addi- tional culture at 37 °C for an additional 7 days. Central cell damage in the isolated islets was monitored by video-mi- croscopy and analyzed quantitatively by a computer-assis- ted image analysis system. The analysis included daily measurement of the diameter and the area of the isolated is- lets and the area of the central cell damage that developed in those islets over time during culture. Histological exami- nation and TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay were used to characterize cell damage and to monitor islet function. RESULTS; Microscopic analysis showed that during the 7 to 14 days of culture at 37 °C, central cell damage appeared in the larger islets with diameters greater than 200 μm, which included both necrotic and apoptotic cell death. Low temperature (26 °C) culture prevented central cell damage of isolated islets. The 7-day culture procedure at 26 °C could inhibit most of the central cell ( excluding diameters greater than 300 μm) damage when the islets were re- warmed to 37 °C. CONCLUSIONS: Our results indicate that central cell da- mage to isolated islets of Langerhans correlates with the size of the islets. Low temperature (26 °C) culture can preventcentral cell damage to the isolated islets, and is capable to successfully precondition these islets for 37 °C culture. These novel findings may help to understand the patho- physiology of early loss of islet tissue after transplantation, and may provide a new strategy to improve graft function in the clinical setting of islet transplantation.
基金funded by the National Natural Science Foundation of China (32371341,31872674)the Scientific and Technologic Foundation of Jilin Province (20230202050NC)the Fundamental Research Funds for the Central Universities (CGZH202206)。
文摘Type 1 diabetes mellitus(T1DM) lacks insulin secretion due to autoimmune deficiency of pancreaticβ-cells.Protecting pancreatic islets and enhancing insulin secretion has been therapeutic approaches.Mannogalactoglucan is the main type of polysaccharide from natural mushroom,which has potential medicinal prospects.Nevertheless,the antidiabetic property of mannogalactoglucan in T1DM has not been fully elucidated.In this study,we obtained the neutral fraction of alkali-soluble Armillaria mellea polysaccharide(AAMP-N) with the structure of mannogalactoglucan from the fruiting body of A.mellea and investigated the potential therapeutic value of AAMP-N in T1DM.We demonstrated that AAMP-N lowered blood glucose and improved diabetes symptoms in T1DM mice.AAMP-N activated unfolded protein response(UPR) signaling pathway to maintain ER protein folding homeostasis and promote insulin secretion in vivo.Besides that,AAMP-N promoted insulin synthesis via upregulating the expression of transcription factors,increased Ca^(2+) signals to stimulate intracellular insulin secretory vesicle transport via activating calcium/calmodulin-dependent kinase Ⅱ(CamkⅡ) and cAMP/PKA signals,and enhanced insulin secretory vesicle fusion with the plasma membrane via vesicle-associated membrane protein 2(VAMP2).Collectively,these studies demonstrated that the therapeutic potential of AAMP-N on pancreatic islets function,indicating that mannogalactoglucan could be natural nutraceutical used for the treatment of T1DM.
基金the Chongqing Science and Health Committee Joint Medical Scientific Research General Project,No.2021MSXM236the Health Development Promotion Project,No.BJHA-CRP-086.
文摘BACKGROUND Langerhans cell histiocytosis(LCH)is a histiocytic proliferative disease caused by clonal proliferation of Langerhans cells,which is currently defined as an inflam-matory myeloid tumor.It is rare in adults,with an incidence of 1–2 per million,and is highly heterogeneous in clinical presentation,with unpredictable disease progression and outcome.CASE SUMMARY A 52-year-old postmenopausal female patient presented to the gynecology department in July 2023 with bilateral vulvar masses.She was diagnosed with recurrent multisystem LCH.The patient had previously been diagnosed with a single-system and single-focal LCH in October 2021 due to a right maxillofacial mass,which resolved after surgical treatment.A chemotherapy regimen was developed after multidisciplinary consultation.Six cycles of chemotherapy resulted in partial remission,and maintenance chemotherapy is currently being administered.CONCLUSION Recurrent LCH involving the bilateral vulva has been poorly reported.Compre-hensive imaging and pathological evaluation is important for diagnosis.The model of joint multidisciplinary specialist diagnosis and treatment is worthy of clinical application.
基金Supported by Hainan Academician Innovation Platform Fund,and the Hainan Province Clinical Medical Center.
文摘BACKGROUND Langerhans cell histiocytosis(LCH)is characterized by diabetes insipidus and is an uncommon occurrence.Pathological biopsies still have a certain degree of diagnostic probability.We present a case in which LCH initially affected the pituitary gland.This resulted in a misdiagnosis of chronic inflammation upon pathological examination.CASE SUMMARY A 25-year-old female exhibited symptoms of diabetes insipidus.Magnetic resonance imaging revealed an enhanced foci in the pituitary gland.After surgical resection of the pituitary lesion,the pathological diagnosis was chronic inflam-mation.However,the patient later experienced bone destruction in the skull and lower limb bones.After the lower limb bone lesion was compared with the initial pituitary lesion,the final diagnosis was modified to LCH.The patient was treated with multiple chemotherapy courses.However,the patient’s condition gradually worsened,and she eventually passed away at home.CONCLUSION LCH should be considered when patients exhibit diabetes insipidus and absence of high signal intensity in the pituitary gland on sagittal T1-weighted image and abnormal enhancement in the pituitary region.
文摘Erdheim-Chester Disease (ECD) is a rare condition and has various differential diagnoses with other forms of histiocytosis, classified as one of non-Langerhans histiocytosis. The diagnosis of this condition remains challenging because its presentation includes non-specific systemic manifestations that can affect different organs caused by deposition of lipids and fibrosis. Most common include bone pain followed by progressive weakness and different lung manifestations. This case is about a rare presentation of ECD with Langerhans Histiocytosis as overlap syndrome, with findings of both diseases in a middle aged woman that presented dyspnea as the first symptom. The patient was treated initially as heart failure and remained without any improvement, being admitted to investigate. After a stricted follow-up, bone and lung involvement were noticed and a skin biopsy unveiled xanthomatized macrophages accompanied by Touton giant cells. This condition remains an important clinical entity and should provide new insights for clinicians dealing with respiratory diseases.
基金Traditional Chinese Medicine Research Program of Hebei Provincial Administration of Traditional Chinese Medicine,No.2022465.
文摘BACKGROUND Langerhans cell histiocytosis(LCH)is a rare clonal proliferative disease of Langerhans cells with unknown pathogenesis.An increasing number of clinicians recognize that LCH has a wide clinical spectrum and a highly varied course.Adults rarely develop LCH.Here,we report a case of adult localized LCH.CASE SUMMARY A 32-year-old woman presented with plaques and ulcers on the vulva and crissum,accompanied by pain that persisted for more than one year.Physical examination revealed a red-infiltrating plaque with ulcerations and exudates in the vulva and crissum.Pathological examination revealed a diffuse infiltration of lymphocytes,eosinophilic granulocytes,and histiocytoid cells in the superficial dermis.Proliferative histiocytoid cells showed mild atypia,partly with kidneyshaped nuclei.Immunohistochemical examination showed that the histiocytoid cells were positive for S100 protein and CD1 and weakly positive for CD68(20%+),with a Ki-67 index of 30%.Laboratory tests did not reveal any other systemic damage.The patient was diagnosed with adult localized LCH and was prescribed oral prednisone(20 mg)once daily.The skin lesions gradually improved and are still being followed-up.CONCLUSION Adult localized LCH is rare and must be differentiated from other common conditions.
基金Supported by the National Natural Science Foundation of China, No. 30200136
文摘AIM: To establish a model of islet-ductal cell transdifferen-tiation to identify the transdifferentiated cells. METHODS: Collagen was extracted from rat tail at first. Purified rat islets were divided into three groups, embedded in collagen gel and incubated respectively in DMEM/F12 alone (control group), DMEM/F12 plus epidermal growth factor (EGF), DMEM/F12 plus EGF and cholera toxin (CT). Transdifferentiation was proved by microscopy, RT-PCR, immunohistochemistry and RIA. RESULTS: Islets embedded in collagen gel plus EGF and CT were cystically transformed and could express new gene cytokeratin 19 while still maintaining the expression of insulin and Pdx-1 genes. Immunohistochemistry demonstrated that the protein of cytokeratin 19 was only expressed in the third group. The insulin content secreted by islets in the third group decreased significantly during the transdiffe-rentiation. CONCLUSION: CT is a crucial factor for the islet-ductal cell transdifferentiation.
基金Supported by the Natural Science Foundation of Shaanxi Province, No. 98SZ-064
文摘AIM: To identify the decreasing effect of xenotransplantion in combination with privileged sites on rejection and death of biological semipermeable membrane-(BSM) encapsulated implanted islets. METHODS: After the BSM experiment in vitro, BSM- encapsulated SD rat's islet-like cell clusters (ICCs) were xenotransplanted into normal dog's brain. Morphological changes were observed under light and transmission electron microscope. The islets and apoptosis of implanted B cells were identified by insulin-TONEL double staining. RESULTS: The BSM used in our study had a favorable permeability, some degree of rigidity, lighter foreign body reaction and toxicity. The grafts consisted of epithelioid cells and loose connective tissue. Severe infiltration of inflammatory cells was not observed. The implanted ICCs were identified 2 mo later and showed typical apoptosis. CONCLUSION: BSM xenotransplantation in combination with the privileged site can inhibit the rejection of implanted heterogeneous ICCs, and death of implanted heterogeneous B cells is associated with apoptosis. 2005 The WJG Press and Elsevier Inc. All rights reserved.
基金Supported by the President Grant for Government Support of Young Russian Scientists,No.075-15-2019-1120.
文摘The pancreas became one of the first objects of regenerative medicine,since other possibilities of dealing with the pancreatic endocrine insufficiency were clearly exhausted.The number of people living with diabetes mellitus is currently approaching half a billion,hence the crucial relevance of new methods to stimulate regeneration of the insulin-secretingβ-cells of the islets of Langerhans.Natural restrictions on the islet regeneration are very tight;nevertheless,the islets are capable of physiological regeneration viaβ-cell self-replication,direct differentiation of multipotent progenitor cells and spontaneousα-toβ-orδ-toβ-cell conversion(trans-differentiation).The existing preclinical models ofβ-cell dysfunction or ablation(induced surgically,chemically or genetically)have significantly expanded our understanding of reparative regeneration of the islets and possible ways of its stimulation.The ultimate goal,sufficient level of functional activity ofβ-cells or their substitutes can be achieved by two prospective broad strategies:β-cell replacement andβ-cell regeneration.The“regeneration”strategy aims to maintain a preserved population ofβ-cells through in situ exposure to biologically active substances that improveβ-cell survival,replication and insulin secretion,or to evoke the intrinsic adaptive mechanisms triggering the spontaneous non-β-toβ-cell conversion.The“replacement”strategy implies transplantation ofβ-cells(as non-disintegrated pancreatic material or isolated donor islets)orβ-like cells obtained ex vivo from progenitors or mature somatic cells(for example,hepatocytes orα-cells)under the action of small-molecule inducers or by genetic modification.We believe that the huge volume of experimental and clinical studies will finally allow a safe and effective solution to a seemingly simple goal-restoration of the functionally activeβ-cells,the innermost hope of millions of people globally.
基金Supported by European Grant Titled Xenome,UE LSHBCT-2006-037377
文摘Although allogeneic islet transplantation can successfully cure type 1 diabetes,it has limited applicability.For example,organs are in short supply;several human pancreas donors are often needed to treat one diabetic recipient;the intrahepatic site may not be the most appropriate site for islet implantation;and immunosuppressive regimens,which are associated with side effects,are often required to prolong survival of the islet graft.An alternative source of insulinproducing cells would therefore be of major interest.Pigs represent a possible alternative source of beta cells.Grafting of pig islets may appear difficult because of the immunologic species barrier,but pig islets have been shown to function in primates for at least 6 mo with clinically incompatible immunosuppression.Therefore,a bioartificial pancreas made of encapsulated pig islets may resolve issues associated with islet allotransplantation.Although several groups have shown that encapsulated pig islets are functional in small-animal models,less is known about the use of bioartificial pancreases in large-animal models.In this review,we summarize current knowledge of encapsulated pig islets,to determine obstacles to implantation in humans and possible solutions to overcome these obstacles.
文摘At present, proven clinical treatments but no cures are available for diabetes, a global epidemic with a huge economic burden. Transplantation of islets ofLangerhans by their infusion into vascularized organs is an experimental clinical protocol, the first approach to attain cure. However, it is associated with lifelong use of immunosuppressants. To overcome the need for immunosuppression, islets are encapsulated and separated from the host immune system by a permselective membrane. The lead material for this application is alginate which was tested in many animal models and a few clinical trials. This review discusses all aspects related to the function of transplanted encapsulated islets such as the basic requirements from a permselective membrane(e.g., allowable hydrodynamic radii, implications of the thickness of the membrane and relative electrical charge). Another aspect involves adequate oxygen supply, which is essential for survival/performance of transplanted islets, especially when using large retrievable macrocapsules implanted in poorly oxygenated sites like the subcutis. Notably, islets can survive under low oxygen tension and are physiologically active at > 40 Torr. Surprisingly, when densely crowded, islets are fully functional under hyperoxic pressure of up to 500 Torr(> 300% of atmospheric oxygen tension). The review also addresses an additional category of requirements for optimal performance of transplanted islets, named auxiliary technologies. These include control of inflammation, apoptosis, angiogenesis, and the intra-capsular environment. The review highlights that curing diabetes with a functional bio-artificial pancreas requires optimizing all of these aspects, and that significant advances have already been made in many of them.
基金Supported by Research Seeds Quest Program in Japan Science and Technology Agency (NS)the Uehara Memorial Foundation (NS)Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports Science and Technology of Japan, B: 22390253 (SE), C: 22591513 (NS)
文摘Islet transplantation could become an ideal treatment for severe diabetes to prevent hypoglycemia shock and irreversible diabetic complications, once some of the major and unresolved obstacles are overcome, including limited donor supplies and side effects caused by permanent immunosuppressant use. Approximately 30 years ago, some groups succeeded in improving the blood glucose of diabetic animals by transplanting encapsulated islets with semi-permeable membranes consisting of polymer. A semi-permeable membrane protects both the inner islets from mechanical stress and the recipient’s immune system (both cellular and humoral immunities), while allowing bidirectional diffusion of nutrients, oxygen, glucose, hormones and wastes, i.e., immune-isolation. This device, which enables immune-isolation, is called encapsulated islets or bio-artificial pancreas. Encapsulation with a semipermeable membrane can provide some advantages: (1) this device protects transplanted cells from the recipient’s immunity even if the xenogeneic islets (from large animals such as pig) or insulin-producing cells are derived from cells that have the potential for differentiation (some kinds of stem cells). In other words, the encapsulation technique can resolve the problem of limited donor supplies; and (2) encapsulation can reduce or prevent chronic administration of immunosuppressants and, therefore, important side effects otherwise induced by immunosuppressants. And now, many novel encapsulated islet systems have been developed and are being prepared for testing in a clinical setting.
文摘AIM: TO explore the effects of fentanyl on insulin release from freshly isolated rat pancreatic islets in static culture. METHODS: Islets were isolated from the pancreas of mature Sprague Dawley rats by common bile duct intraductal collagenase V digestion and were purified by discontinuous Ficoll density gradient centrifugation. The islets were divided into four groups according to the fentanyl concentration: control group (0 ng/mL), group I (0.3 ng/mL), group I (3.0 ng/mL), and group III (30 ng/mL). In each group, the islets were co-cultured for 48 h with drugs under static conditions with fentanyl alone, fentanyl + 0.1 μg/mL naloxone or fentanyl + 1.0 μg/mL naloxone. Cell viability was assessed by the MTT assay. Insulin release in response to low and high concentrations (2.8 mmol/L and 16.7 mmol/L, respectively) of glucose was investigated and electron microscopy morphological assessment was performed. RESULTS: Low- and high-glucose-stimulated insulin release in the control group was significantly higher than in groups I and II (62.33 ± 9.67 μIU vs 47.75 ± 8.47 μIU, 39.67 ± 6.18 μIU and 125.5 ± 22.04 μIU vs 96.17 ± 14.17 μIU, 75.17 ± 13.57 μIU, respectively, P 〈 0.01) and was lowest in group III (P 〈 0.01). After adding 1 μg/mL naloxone, insulin release in groups II and II was not different from the control group. Electron microscopy studies showed that the islets were damaged by 30 ng/ml fentanyl. CONCLUSION: Fentanyl inhibited glucose-stimulated insulin release from rat islets, which could be prevented by naloxone. Higher concentrations of fentanyl significantly damaged β-cells of rat islets.
文摘Because insulin released by the β-cells of pancreatic islets is the main regulator of glucose levels, the quantitative modeling of their glucose-stimulated insulin secretion is of obvious interest not only to improve our understanding of the processes involved, but also to allow better assessment of β -cell function in diabetic patients or islet transplant recipients as well as the development of improved artificial or bioartificial pancreas devices. We have recently developed a general, local concentrations-based multiphysics computational model of insulin secretion in avascular pancreatic islets that can be used to calculate insulin secretion for arbitrary geometries of cultured, perifused, transplanted, or encapsulated islets in response to various glucose profiles. Here, experimental results obtained from two different dynamic glucose-stimulated insulin release (GSIR) perifusion studies performed by us following standard procedures are compared to those calculated by the model. Such perifusion studies allow the quantitative assessment of insulin release kinetics under fully controllable experimental conditions of varying external concentrations of glucose, oxygen, or other compounds of interest, and can provide an informative assessment of islet quality and function. The time-profile of the insulin secretion calculated by the model was in good agree- ment with the experimental results obtained with isolated human islets. Detailed spatial distributions of glucose, oxygen, and insulin were calculated and are presented to provide a quantitative visualization of various important aspects of the insulin secretion dynamics in perifused islets.
基金Subject of Jiangsu Province135 Projects (2001 31)
文摘Objective: To evaluate the immunoisola ti ng effects of barium-alginate microencapsulation on islets allograft survival. Methods: The nonmicroencapsulated and microencapsulated islets w ere transplanted under the kidney capsule or intraperitoneally into Wistar rat w ith STZ-induced diabetes. The blood glucose and insulin secretion of grafts wer e observed. Graft function was tested by oral glucose tolerance test (OGTT). Results: ①Five diabetic rats became normoglycemic for 48 to 72 h after microencapsulated islets transplantation. The survival of transplanted i slets was on an average of 6 W. ②The normalization of the glycemia and insulin in the transplanted rats was associated with normal glucose and insulin profiles in response to OGTT. Conclusion: Microencapsulation with barium -alginate membrane can prolong islet survival and protect islets against allore jection.
文摘Damped wave diffusion effects during oxygen transport in islets of Langerhans is studied. Simultaneous reaction and diffusion models were developed. The asymptotic limits of first and zeroth order in Michaelis and Menten kinetics was used in the study. Parabolic Fick diffusion and hyperbolic damped wave diffusion were studied separately. Method of relativistic transformation was used in order to obtain the solution for the hyperbolic model. Model solutions was used to obtain mass inertial times. Convective boundary condition was used. Sharma number (mass) may be used in evaluating the importance of the damped wave diffusion process in relation to other processes such as convection, Fick steady diffusion in the given application. Four regimes can be identified in the solution of hyperbolic damped wave diffusion model. These are;1) Zero Transfer Inertial Regime, 0 0≤τ≤τinertia;2) Rising Regime during times greater than inertial regime and less than at the wave front, Xp > τ, 3) at Wave front , τ = Xp;4) Falling Regime in open Interval, of times greater than at the wave front, τ > Xp. Method of superposition of steady state concentration and transient concentration used in both solutions of parabolic and hyperbolic models. Expression for steady state concentration developed. Closed form analytic model solutions developed in asymptotic limits of Michaelis and Menten kinetic at zeroth order and first order. Expression for Penetration Length Derived-Hypoxia Explained. Expression for Inertial Lag Time Derived. Solution was obtained by the method of separation of variables for transient for parabolic model and by the method of relativistic transformation for hyperbolic models. The concentration profile was expressed as a sum of steadty state and transient parts.
文摘We have previously demonstrated that allogeneic human bone marrow (BM) supports human islet function and longevity in vitro. We hypothesize that BM supporting human islets may include to increase β-cell in cultured islets. In this study, we developed a method to quantify insulin-producing β cells from cultured islets by using immunofluorescent staining and flow cytometry analysis to explore this possibility. The results show that human islets cocultured with BM for 39 days contained a significantly higher number of insulin-positive β cells (42.3% ± 4.5%) compared to the islet-only cultures (1.15% ± 0.78%), and increased insulin release levels evaluated by ELISA is consistent with increased β cells in same culture condition. Human islet culture with BM significantly increase β-cells while islet only culture lost β-cells in same culture period supports the possibility of BM increasing β-cells in cultured islets.
文摘Aiming at Delaunay triangulation with islets constrains in terrain simulation. A general Delaunay triangulation algorithm for constrained data set with islets is proposed. The algorithm firstly constructs Constrained Delaunay Triangulation with constraint polygons which are inner boundary of islets, then according to topological relations within edge, surface, arc segment, applies bidirectional search to find the triangle in islet, lastly it carries on certain corresponding processing to complete the Delaunay triangulation algorithm with islets. The analyses show the algorithm simple, fast speed. The algorithm can be used in 3-D terrain vision.
文摘Background and Objective: Islet autotransplantation is performed to preserve endocrine function in patients undergoing pancreatic resections for painful chronic pancreatitis. We characterized islets isolated from chronic pancreatitis patients (CP) of tropical region. Patients and Methods: Pancreatic tissues were obtained from CP patients with and without diabetes undergoing pancreatic resections (n = 35) and brain-dead multi organ donors (n = 6;considered as controls). Islets isolated were assessed for yield, purity, viability and in vitro islet function (Glucose stimulated insulin release, GSIR) as per standard protocols. Results: Islets from CP patients without diabetes were similar to controls in yield (control 4120 - 6100 IE/g, CP 3550 - 5660 IE/g), purity (control 78% ± 12%, CP 70% ± 8.2%) and viability (control 85% ± 8%, CP 81% ± 10%) and islets from CP patients with diabetes showed decreases in yield (3002 - 2300 IE/g), purity (61% ± 16%) and viability (62% ± 21%). Islets measuring 50 - 200 μ were similar in abundance in controls (94.74% ± 3.2%) and CP patients with and without diabetes, 86.31% ± 4.9%, 91.03% ± 3.8%. GSIR of islets from CP patients and controls were similar at 5.5 mM glucose (2.8 - 3.1 μU/ml). However, GSIR at 16.5 mM glucose was decreased in CP patients (control 18.5 ± 0.6, CP without diabetes 11.8 ± 0.3, CP with diabetes 4.3 ± 0.3 μU/ml). Conclusion: Our results demonstrate suitability of islets isolated from CP patients of tropical region for autotransplantation.