Effect of acetyl L-carnitine on human retinal pigment epithelium-19 cells in hypoxic conditions

AIM:To investigate the effect of acetyl-L-carnitine(ALCAR)on cell viability,morphological integrity,and vascular endothelial growth factor(VEGF)expression in human retinal pigment epithelium(ARPE-19)cells using a hypoxic model.METHODS:In the first set of experiments,the optimal CoCl_(2) dose was determined by exposing ARPE-19 cell cultures to different concentrations.To evaluate the effect of ALCAR on cell viability,five groups of ARPE-19 cell culture were established that included a control group,a sham group(200μM CoCl_(2)),and groups that received 1,10 and 100 mM doses of ALCAR combined with 200μM CoCl_(2),respectively.The cell viability was measured by MTT assay.The morphological characteristics of cells were observed by an inverted phase contrast microscope.The levels of VEGF and HIF-1α secretion by ARPE-19 cells were detected by enzyme linked immunosorbent assay(ELISA)assay.RESULTS:ARPE-19 cells were exposed to different doses of CoCl_(2) in order to create a hypoxia model.Nevertheless,when exposed to a concentration of 200μM CoCl_(2),a notable decrease in viability to 83% was noted.ALCAR was found to increase the cell viability at 1 mM and 10 mM concentrations,while the highest concentration(100 mM)did not have an added effect.The cell viability was found to be significantly higher in the groups treated with a concentration of 1 mM and 10 mM ALCAR compared to the Sham group(P=0.041,P=0.019,respectively).The cell viability and morphology remained unaffected by the greatest dose of ALCAR(100 mM).The administration of 10 mM ALCAR demonstrated a statistically significant reduction in the levels of VEGF and HIF-1α compared with the Sham group(P=0.013,P=0.033,respectively).CONCLUSION:The findings from the current study indicate that ALCAR could represent a viable therapeutic option with the potential to open up novel treatment pathways for retinal diseases,particular relevance for age-related macular degeneration(AMD).However,to fully elucidate ALCAR’s application potential in retinal diseases,additional investigation is necessary to clearly define the exact mechanisms involved.

Decreased contrast sensitivity of visual cortical cells to visual stimuli accompanies a reduction of intracortical inhibition in old cats

Psychophysical experiments on human and animal subjects have proven that aged individuals show significantly reduced visual contrast sensitivity compared with young adults.To uncover the possible neural mechanisms,we used extracellular single-unit recording techniques to examine the response of V1（primary visual cortex） neurons as a function of visual stimulus contrast in both old and young adult cats（Felis catus）.The mean contrast sensitivity of V1 neurons to visual stimuli in old cats decreased significantly relative to young adult cats,consistent with findings reported in old primates.These results indicate that aging can affect contrast sensitivity of visual cortical cells in both primate and non-primate mammalian animals,and might contribute to the reduction of perceptual visual contrast sensitivity in aged individuals.Further,V1 cells of old cats exhibited increased responsiveness,decreased signal-to-noise ratio,and enlarged receptive field（RF） size compared with that of young adult cats,which indicated that decreased contrast sensitivity of V1 neurons accompanied a reduction of intracortical inhibition during senescence.

Therapeutic effect of microencapsulated porcine retinal pigmented epithelial cells transplantation on rat model of Parkinson's disease

Object To investigate the therapeutic effect of microencapsulated porcine retinal pigmented epithelial cells （RPE-M） transplantation on rat model of Parkinson＇s disease （PD）. Methods Primary porcine RPE cells were harvested by enzyme digestion and expanded in culture medium. Determine the levels ofdopamine （DA） and homovanillic acid （HVA） by high performance liquid chromatography electrochemical （HPLC） assay, and the levels of brain-derived neurotrophic factor （BDNF） and glial-derived neurotrophic factor （GDNF） were detected by ELISA. Alginate-polylysine-alginate （APA） microencapsulated cells were produced by using a high voltage electrostatic system. PD rat model was established by unilateral injection of 6-hydroxydopamine （6-OHDA） into the medial forebrain bundle （MFB）. After that, the RPE-M was transplanted into the corpus striatum of PD rat, and then the rotation test scores were recorded and biochemical changes of the corpus striatum were tested. Results The levels of DA, HVA, BDNF and GDNF secreted by RPE were stable in the RPE culture supernatant and were not changed by the microencapsulation. Eighty-three percent rats developed PD by unilateral lesion of 6-OHDA in the MFB. The RPE-M transplantation had therapeutic effect on 33% PD rats. Conclusion Porcine RPE cells grow actively in vitro and could secrete DA, HVA, BDNF, and GDNF constantly, which does not be affected by the passage culture and the APA miroencapsulation. RPE-M transplantation of may be a curative therapy for PD.

Prognostic significance of cell infiltrations of immunosurveillance in colorectal cancer

AIM: To determine whether the mast cell (MCs) and tumor-associated macrophage (TAMs) counts have any correlation with clinical outcome in colorectal cancer, and to investigate whether MCs undergo phenotypic changes in colorectal cancer.METHODS: The MC and TAM counts were determined immunohistochemically in 60 patients with colorectal cancer and the depth of invasion, lymph node metastasis rate, distant metastasis rates, and survival rates were compared between patients with low (less than the mean number of positive cells) and high (more than the mean number of positive cells) cell counts.RESULTS: Both patients with a low MC count and patients with a low TAM count had significantly deeper depth of invasion than those with a high MC count and those with a high TAM count (P＜0.01 and P＜0.01 respectively).Patients with a high MC count and patients with a high TAM count were significantly higher showing significantly lower rates of lymph node metastasis, distant metastasis than those with a low MC count and those with a low TAM count. There were significant positive correlation between MC counts and TAM counts (r = 0.852, P＜0.01).In both cancerous tissue and normal colorectal tissue,the predominant MC phenotype was MCTC. The 5-year survival rate estimated was significantly lower in both patients with a low MC count and patients with a low TAM count than in those with a high MC count and those with a high TAM count (P＜0.05 and P＜0.01 respectively).CONCLUSION: There appears to be a direct relationship between the number of MCs and clinical outcome in patients with colorectal cancer, even though MCs exhibited no significant phenotypic changes. TAM count is of value to predict the clinical outcome or prognosis. It is more beneficial for estimating biological character of colorectal carcinoma to combine MC and TAM counts.

Stem cells for liver tissue repair:Current knowledge and perspectives

Stem cells from extra-or intrahepatic sources have been recently characterized and their usefulness for the generation of hepatocyte-like lineages has been demonstrated. Therefore, they are being increasingly considered for future applications in liver cell therapy. In that field, liver cell transplantation is currently regarded as a possible alternative to whole organ transplantation, while stem cells possess theoretical advantages on hepatocytes as they display higher in vitro culture performances and could be used in autologous transplant procedures. However, the current research on the hepatic fate of stem cells is still facing difficulties to demonstrate the acquisition of a full mature hepatocyte phenotype, both in vitro and in vivo. Furthermore, the lack of obvious demonstration of in vivo hepatocyte-like cell functionality remains associated to low repopulation rates obtained after current transplantation procedures. The present review focuses on the current knowledge of the stem cell potential for liver therapy. We discuss the characteristics of the principal cell candidates and the methods to demonstrate their hepatic potential in vitro and in vivo. We finally address the question of the future clinical applications of stem cells for liver tissue repair and the technical aspects that remain to be investigated.

Inhibition of invasiveness and expression of epidermal growth factor receptor in human colorectal carcinoma cells induced by retinoic acid

Human amniotic basement membrane (HABM) model and agarose drop explant method were used to in-vestigate the effects of retinoic acid(RA) on the invasive-ness alld adhesiveness to the basement membrane, and the migration of a highly invassive human colorectal cancer cell line CCL229. Results showed that 5 ×106 MRA markedly reduced the in vitro invasiveness and adhesiveness to the HABM, and the migration of the CCL229 cells. In addi-tion, to elucidate the relation between expression of epider-mal growth factor receptor (EGFR) and the invasiveness of the colorectal carcinoma cells, two well-differentiated, but with different invasiveness colorectal cancer cell lines were compared at mRNA level for expressioll of EGFR by using EGFR cDNA probe labeled with digoxigenin (DIG). Expression of EGFR was showll to be markedly higher in the highly invassive CCL229 cells than that in the low in- vasive CX-1 cells. Furthermore, expression of EGFR in RA treated CCL229 cells gradually decreased with time,the level being the lowest on day 6 of the RA treatment.

Growth Inhibition and Apoptosis Induced by Retinoic Acid Combined with Interferon Alpha-2a on Transitional Cell Carcinoma of Bladder

Objective:To identify new favorable agents and develop novel approaches for the chemoprevention and treatment of superficial bladder cancer and investigate the effects of combination of retinoids and interferon α-2a on growth inhibition and apoptosis induction in bladder cancer cell lines. Methods:Four bladder cancer cell lines,grade 1 to 3,and two retinoids,all-trans-retinoic acid(ATRA),9-cis retinoic acid(9cRA),combined with interferon α-2a(INF),were used in the study.We compared the competence of these agents to inhibit growth,induce apoptosis,affect the expression of nuclear retinoid receptors,and modulate STAT1 protein. Results: Most of the bladder cancer cell lines were resistant to the effect of ATRA and 9cRA on growth inhibition and apoptosis induction,even at higher concentration(10 -5M).The effects of ATRA and 9c RA on cell growth and apoptosis were enhanced by INF α- 2a. Combination of ATRA and IFNα-2a induced RARβ and Stat 1 expression in three bladder cancer cell lines. Conclusion:The results demonstrated that INFα-2a synergize with the inhibitory effect of ATRA and 9c RA on the growth inhibition and apoptosis of bladder cancer cells in vitro,which suggested that it has a potential interest for the treatment of transitional cell carcinoma of bladder.

Immunosurveillance function of human mast cell?

Mast cell (MC) is so widely recognized as a critical effector in allergic disorders that it can be difficult to think of MC in any other context. Indeed, MCs are multifunctional and recently shown that MCs can also act as antigen presenters as well as effector elements of human immune system. First observations of their possible role as anti-tumor cells in peri- or intra-tumoral tissue were mentioned five decades ago and a high content of MCs is considered as a favorable prognosis,consistent with this study. Believers of this hypothesis assumed them to be inhibitors of tumor development through their pro-apoptotic and -necrolytic granules e.g.,granzymes and TNF-α. However, some still postulate them to be enhancers of tumor development through their effects on angiogenesis due to mostly tryptase.There are also some data suggesting increased MC density causes tumor development and indicates bad prognosis. Furthermore, since MC-associated mediators have shown to influence various aspects of tumor biology, the net effect of MCs on the development/progression of tumors has been difficult to evaluate. For instance, chymase induces apoptosis in targets; yet,tryptase, another MC protease, is a well-known mitogen.MCs with these various enzyme expression patterns may mediate different functions and the predominant MC type in tissues may be determined by the environmental needs. The coexistence of tryptase-expressing MCs(MCT) and chymase and tryptase-expressing MCs (MCTC)in physiological conditions reflects a naturally occurring balance that contributes to tissue homeostasis. We have recently discussed the role and relevance of MC serine proteases in different bone marrow diseases.

Application of video-assisted thoracic surgery in the standard operation for thoracic tumors

Objective： To evaluate the short-term outcomes of video-assisted thoracic surgery （VATS） for thoracic tumors. Methods： The data of 1,790 consecutive patients were retrospectively reviewed. These patients underwent VATS pulmonary resections, VATS esophagectomies, and VATS resections of mediastinal tumors or biopsies at the Cancer Institute ＆ Hospital, Chinese Academy of Medical Sciences between January 2009 and January 2012. Results： There were 33 patients converted to open thoracotomy （OT, 1.84%）. The overall morbidity and mortality rate was 2.79% （50/1790） and 0.28% （5/1790）, respectively. The overall hospitalization and chest tube duration were shorter in the VATS lobectomy group （n=949） than in the open thoracotomy （OT） lobectomy group （n=753）. There were no significant differences in morbidity rate, mortality rate and operation time between the two groups. In the esophageal cancer patients, no significant difference was found in the number of nodal dissection, chest tube duration, morbidity rate, mortality rate, and hospital length of stay between the VATS esophagectomy group （n=8 1） and open esophagectomy group （n=81）. However, the operation time was longer in the VATS esophagectomy group. In the thymoma patients, there was no significant difference in the chest tube duration, morbidity rate, mortality rate, and hospital length of stay between the VATS thymectomy group （n=41） and open thymectomy group （n=41）. However, the operation time was longer in the VATS group. The median tumor size in the VATS thymectomy group was comparable with that in the OT group. Conclusions： In early-stage （Ⅰ/Ⅱ） non-small cell lung cancer patients who underwent lobectomies, VATS is comparable with the OT approach with similar short-term outcomes. In patients with resectable esophageal cancer, VATS esophagectomy is comparable with OT esophagectomy with similar morbidity and mortality. VATS thymectomy for Masaoka stage I and II thymoma is feasible and safe, and tumor size is not contraindicated. Longer follow-ups are needed to determine the oncologic equivalency of VATS lobectomy, esophagectomy, and thymectomy for thymoma vs. OT.

ABC transporters,neural stem cells and neurogenesis - a different perspective

Stem cells intrigue. They have the ability to divide exponentially, recreate the stem cell compartment, as well as create differentiated cells to generate tissues. Therefore, they should be natural candidates to provide a renewable source of cells for transplantation applied in regenerative medicine. Stem cells have the capacity to generate specific tissues or even whole organs like the blood, heart, or bones. A subgroup of stem cells, the neural stem cells （NSCs）, is characterized as a self-renewing population that generates neurons and glia of the developing brain. They can be isolated, genetically manipulated and differentiated in vitro and reintroduced into a developing, adult or a pathologically altered central nervous system. NSCs have been considered for use in cell replacement therapies in various neurodegenerative diseases such as Parkinson＇s disease and Alzheimer＇s disease. Characterization of genes with tightly controlled expression patterns during differentiation represents an approach to understanding the regulation of stem cell commitment. The regulation of stem cell biology by the ATP-binding cassette （ABC） transporters has emerged as an important new field of investigation. As a major focus of stem cell research is in the manipulation of cells to enable differentiation into a targeted cell population; in this review, we discuss recent literatures on ABC transporters and stem cells, and propose an integrated view on the role of the ABC transporters, especially ABCA2, ABCA3, ABCB 1 and ABCG2, in NSCs＇ proliferation, differentiation and regulation, along with comparisons to that in hematopoietic and other stem cells.

Alpha-fetoprotein triggers hepatoma cells escaping from immune surveillance through altering the expression of Fas/FasL and tumor necrosis factor related apoptosis-inducing ligand and its receptor of lymphocytes and liver cancer cells

AIM: To investigate the mechanism of α-fetoprotein (AFP)in escaping from the host immune surveillance of hepatocellular carcinoma.METHODS: AFP purified from human umbilical blood was administrated into the cultured human lymphoma Jurkat T cell line or hepatoma cell line, Bel7402 in vitro. The expression of tumor necrosis factor related apoptosisinducing ligand (TRAIL) and its receptor (TRAILR) mRNA were analyzed by Northern blot and Western blot wasused to detect the expression of Fas and Fas ligand (FasL)protein.RESULTS: AFP (20 mg/L) could promote the expression of FasL and TRAIL, and inhibit the expression of Fas and TRAILR of Bel7402 cells. For Jurkat cell line, AFP could suppress the expression of FasL and TRAIL, and stimulate the expression of Fas and TRAILR. AFP also could synergize with Bel7402 cells to inhibit the expression of FasL protein and TRAIL mRNA in Jurkat cells. The monoclonal antibody against AFP (anti-AFP) could abolish these functions of AFP.CONCLUSION: AFP is able to promote the expression of FasL and TRAIL in hepatoma cells and enhance the expression of Fas and TRAILR in lymphocytes. These could elicit the escape of hepatocellular carcinoma cells from the host's lymphocytes immune surveillance.

DIFFERENT RESPONSES OF CHORIOCAPILLARY ENDOTHELIAL CELLS AND RETINAL CAPILLARY ENDOTHELIAL CELLS TO MITOGENIC AND VASOACTIVE FACTORS

The responses of choriocapillary endothelial cells(CCE) and retinal capillary endothelial cells(RCE) in culture,in terms of phosphoinositide(PI) breakdown and cellular mitogenesis, to retinal pigment epithelial cell(RPE)-conditioned medium and vasoactive agents have been compared. RPE-conditioned medium did not induce PI breakdown in either type of cell. However, it stimulated DNA synthesis in CCE but not in RCE. Bradykinin(BDK) acted as both a fast signaling and a slow mitogenic factor on CCE, but BDK did not affect PI turnover or DNA synthesis in RCE. In contrast, thrombin stimulated PI turnover in RCE but not in CCE, though it did not induce 3H-thymidine incorporation into either type of cell. These differences in cellular functions between CCE and RCE following stimulation suggest that induction of DNA synthesis and receptor-mediated PI turnover by external factors is determined, at least in part, by the origin of the capillary endothelial cell. Therefore, extrapolation to CCE pathophysiology from experiments using endothelial cells from other capillary origins may not be valid.

Retinol-binding protein, acute phase reactants and Helicobacter pylori infection in patients with gastric adenocarcinoma

AIM： To determine the serum levels of c-reactive protein （CRP）, transferrin （TRF）, a2-macroglobulin （A2M）, ceruloplasmin （CER）, al-acid glycoprotein （AAG）, prealbumin （P-ALB） and retinol-binding protein （RBP） in gastric carcinoma patients and to explore their possible correlation with underlying Helicobacter pylori （H pylon） infection. METHODS： We measured the serum levels of CRP, TRF, A2M, CER, AAG, P-ALB, and RBP in 153 preoperative patients （93 males; mean age： 63.1±11.3 years） with non-cardia gastric adenocarcinoma and 19 healthy subjects. RESULTS： The levels of CRP, CER, RBP, and AAG in cancer patients were significantly higher than those in healthy controls （P〈0.0001）, while no difference was found regarding the TRF, P-ALB, and A2M levels. Cancer patients with H py/ori infection had significantly lower RBP values compared to non-infected ones （P〈0.0001） and also higher values of CRP and AAG （P = 0.09 andP = 0.08, respectively）. CONCLUSION： High serum levels of CRP, CER and AAG in cancer patients do not seem to be related to H pylori infection. Retinol-binding protein seems to discriminate between infected and non-infected patients with gastric carcinoma. Further studies are needed to explore if it is directly involved in the pathogenesis of the disease or is merely an epiphenomenon.

Pretransplantation fetal-maternal microchimerism in pediatric liver transplantation from mother

AIM To investigate the rates of pretransplantation fetalmaternal microchimerism(MC) and its effect on rejection in children receiving maternal liver grafts. METHODS DNA or blood samples before liver transplantation(LT) were available in 45 pediatric patients and their mothers. The presence of pretransplantation MC to non-inherited maternal antigens(NIMAs)(NIMA-MC) in the peripheral blood was tested using nested PCRsingle-strand conformation polymorphism analysis for the human leukocyte antigen(HLA)-DRB1 alleles. NIMA-MC was successfully evaluated in 26 of the 45 children. Among these 45 pediatric LT recipients,23 children(51.1%) received transplants from maternal donors and the other 22 from non-maternal donors.RESULTS Among these 26 children,pretransplantation NIMAMC was detected in 23.1%(n = 6),6.1(range,0.8-14) years after birth. Among the children with a maternal donor,the rate of biopsy-proven cellular rejection(BPCR) was 0% in patients with NIMA-MC positivity(0/3) and those with HLA-DR identity with the mother(0/4),but it was 50% in those with NIMA-MC negativity(5/10). Patients with NIMA-MC positivity or HLA-DR identity with the mother showed significantly lower BPCR rate compared with NIMA-MC-negative patients(0% vs 50%,P = 0.04). NIMA-MC-positive patients tended to show lower BPCR rate compared with NIMAMC-negative patients(P = 0.23). CONCLUSION The presence of pretransplantation NIMA-MC or HLADR identity with the mother could be associated with BPCR-free survival in pediatric recipients of LT from maternal donors.

Association of cyclin D1, p16 and retinoblastoma protein expressions with prognosis and metastasis of gallbladder carcinoma

AIM: To investigate the role of cyclin D1, p16 and retinoblastoma in cancerous process of gallbladder carcinomas and to assess the relation between cyclin D1, p16, Rb and the biological characteristics of gallbladder carcinoma. METHODS: Forty-one gallbladder carcinoma, 7 gallbladder adenoma and 14 chronic cholecystitis specimens were immunohistochemically and histopathologically investigated for the relation of cyclin D1, p16 and Rb with Nevin staging and pathologic grading. RESULTS: The expression rates of abnormal cyclin Dl in gallbladder carcinoma (68.3%)and gallbladder adenoma (57.1%) were significantly higher than those in chronic cholecystitis (7.1%) (P<0.05). No significant difference was found both among the pathological grades G1, G2 and G3 and among Nevin stagings S1-S2, S3 and S4-S5 of gallbladder carcinoma. The positive rates of p16 (48.8%) and Rb (58.5%) in gallbladder carcinoma were significantly lower compared to those in adenoma (100.0%) and cholecystitis (100.0%) (P<0.05). The positive rates of p16 and Rb in Nevin stagings S1-S2 (80.0% and 90.0%) and S3 (46.2% and 61.5%) gallbladder carcinomas were significantly higher than those in S4-S5(33.3% and 38.8%) (P<0.05), and those in pathologic grades G1(54.5% and 81.8%) and G2 (50.0% and 62.5%) gallbladder carcinoma were significantly higher than those in G3 (28.6% and 35.7%) (P<0.05). The protein expression of p16 and Rb had a negative-correlation in gallbladder carcinoma (r= -0.2993, P<0.05), and this negative-correlation was correlated with Nevin staging (P<0.05). Moreover, the protein expression of p16 and cyclin Dl had a negative-correlation in gallbladder carcinoma (r = -0.9417, P<0.05). CONCLUSION: Cyclin Dl may play a role in the early stage of gallbladder carcinoma. Mutation of p16 and Rb genes might be correlated with progression of gallbladder carcinoma. Analysis of p16 and Rb can estimate the prognosis of gallbladder carcinoma. Expression of p16 and Rb may be correlated with Nevin staging and pathologic grading in gallbladder carcinoma.

22-gauge core vs 22-gauge aspiration needle for endoscopic ultrasound-guided sampling of abdominal masses

AIM To compare the aspiration needle(AN) and core biopsy needle(PC) in endoscopic ultrasound-guided fine needle aspiration(EUS-FNA) of abdominal masses.METHODS Consecutive patients referred for EUS-FNA were included in this prospective single-center trial. Each patient underwent a puncture of the lesion with both standard 22-gauge(G) AN(Echo Tip Ultra; Cook Medical, Bloomington, Indiana, United States) and the novel 22 G PC(Echo Tip Pro Core; Cook Medical, Bloomington, Indiana, United States) in a randomized fashion; histology was attempted in the PC group only. The main study endpoint was the overall diagnostic accuracy, including the contribution of histology to the final diagnosis. Secondary outcome measures included material adequacy, number of needle passes, and complications.RESULTS Fifty six consecutive patients(29 men; mean age 68 years) with pancreatic lesions(n = 38), lymphadenopathy(n = 13), submucosal tumors(n = 4), or others lesions(n = 1) underwent EUS-FNA using both of the needles in a randomized order. AN and PC reached similar overall results for diagnostic accuracy(AN: 88.9 vs PC: 96.1, P = 0.25), specimen adequacy(AN: 96.4% vs PC: 91.1%, P = 0.38), mean number of passes(AN: 1.5 vs PC: 1.7, P = 0.14), mean cellularity score(AN: 1.7 vs PC: 1.1, P = 0.058), and complications(none). A diagnosis on the basis of histology was achieved in the PC group in 36(64.3%) patients, and in 2 of those as the sole modality. In patients with available histology the mean cellularity score was higher for AN(AN: 1.7 vs PC: 1.0, P = 0.034); no other differences were of statistical significance.CONCLUSION Both needles achieved high overall diagnostic yields and similar performance characteristics for cytological diagnosis; histological analysis was only possible in 2/3 of cases with the new needle.

Bacteriorhodopsin and SWCNT Scaffold for Optical Nanobiosensor

This paper describes theoretical steps to develop an optical nanobiosensor using bacteriorhodopsin （BR） as the biomembrane and Single-Walled Carbon NanoTube （SWCNT） as the scaffold. Bacteriorhodopsin is a retinal protein used by archaea that come under the family of halobacteria. This retinal protein acts as a proton pump and resulting proton gradient is used to change the voltage that pass across the drain and source. The biosensor contains nano ISFET where the channel is made of a carbon nanotube for the conduction of current. The gate is replaced by bacteriorhodopsin biomembrane. Bacteriorhodopsin can be used as a molecular-level ultra fast bi-stable red / green photo switch for making 3D optical molecular memories that reliably store data with 10,000 molecules/bit. The molecules switch in femtoseconds. Biomembrane will sense 510 nm and 650 nm wavelength of light and the sensing voltage can be used to convert the data into digital signals. This molecular level memory device can be used for ‘Read-Write＇ operations. The sensor performance will also be ultra fast since it uses photons for the data storage, which are much faster than electrons used in normal memory devices, and the 3D storage capacity is much higher maximum of 10^13/cm^2.

In Vitro Model of Human Choroidal Neovascular

Choroidal capillary endothelia cell （CEC） plays a critical role in the development of choroidal neovascularization which is one of the major causes of blindness. An effective method for CEC cultivation was proposed. The isolation of human choroidal CECs using micro dissection followed by the use of superparamagnetic beads （Dynabeads） coated with the CD 31, which selectively binds to the endothelial cell surface. Cells bound to beads were isolated using a magnetic particle concentrator. The CECs were planted into type Ⅳ collagen coated 24 well plates. The results show that the primary cultured CEC is induced to tube formation in collagen Ⅳ coated environment, which can be presented as an in vitro model of choroidal neovascularization.

Erythropoietin Receptor Positive Circulating Progenitor Cells and Endothelial Progenitor Cells in Patients with Different Stages of Diabetic Retinopathy

Objective To investigate the possible involvement of erythropoietin （EPO）/erythropoietin receptor （EPOR） system in neovascularization and vascular regeneration in diabetic retinopathy （DR）. Methods EPOR positive circulating progenitor cells （CPCs： CD34^＋） and endothelial progenitor cells （EPCs： CD34^＋KDR^＋） were assessed by flow cytometry in type 2 diabetic patients with different stages of DR. The cohort consisted of age- and sex-matched control patients without diabetes （n=7）, non-prolif- erative DR （NPDR, n=7）, proliferative DR （PDR, n=8）, and PDR complicated with diabetic nephropathy （PDR-DN, n=7）. Results The numbers of EPOR^＋ CPCs and EPOR^＋ EPCs were reduced remarkably in NPDR corn pared with the control group （both P（0.01）, whereas rebounded in PDR and PDR-DN groups in varying degrees. Similar changes were observed in respect of the proportion of EPOR^＋ CPCs in CPCs （NPDR vs. control, P（0.01） and that of EPOR^＋ EPCs in EPCs （NPDR vs. control, P〈0.05）. Conclusion Exogenous EPO, mediated via the EPO/EPOR system of EPCs, may alleviate the impaired vascular regeneration in NPDR, whereas it might aggravate retinal neovascularization in PDR due to a rebound of EPOR^＋ EPCs associated with ischemia.

Endocytosis unplugged： multiple ways to enter the cell

Endocytosis occurs at the cell surface and involves internalization of the plasma membrane （PM） along with its constituent membrane proteins and lipids. Endocytosis is involved in sampling of the extracellular milieu and also serves to regulate various processes initiated at the cell surface. These include nutrient uptake, signaling from cell- surface receptors, and many other processes essential for cell and tissue functioning in metazoans. It is also central to the maintenance of PM lipid and protein homeostasis. There are multiple means of internalization that operate concurrently, at the cell surface. With advancement in high-resolution visualization techniques, it is now possible to track multiple endocytic cargo at the same time, revealing a remarkable diversity of endocytic processes in a single cell. A combination of live cell imaging and efficient genetic manipulations has also aided in understanding the functional hierarchy of molecular players in these mechanisms of internalization. Here we provide an account of various endocytic routes, their mechanisms of operation and occurrence across phyla.