Risk factors for small bowel angioectasia:The impact of visceral fat accumulation

AIM: To investigate visceral fat accumulation in association with the risk of small bowel angioectasia.METHODS: We retrospectively investigated 198 consecutive patients who underwent both capsule endoscopy and CT for investigation of obscure gastrointestinal bleeding(OGIB) from January 2009 to September 2013. The visceral fat area(VFA) and subcutaneous fat area were measured by CT, and information on comorbidities, body mass index, and medications was obtained from their medical records.Logistic regression analysis was used to evaluate associations.RESULTS: Capsule endoscopy revealed small bowel angioectasia in 18/198(9.1%) patients with OGIB.Compared to patients without small bowel angioectasia,those with small bowel angioectasia had a significantly higher VFA(96 ± 76.0 cm2 vs 63.4 ±51.5 cm2, P = 0.016) and a higher prevalence of liver cirrhosis(61% vs 22%, P < 0.001). The proportion of patients with chronic renal failure was higher in patients with small bowel angioectasia(22% vs 9%,P = 0.11). There were no significant differences in subcutaneous fat area or waist circumference. The prevalence of small bowel angioectasia progressively increased according to the VFA. Multivariate analysis showed that the VFA [odd ratio(OR) for each 10-cm2 increment = 1.1; [95% confidence interval(CI):1.02-1.19; P = 0.021] and liver cirrhosis(OR = 6.1,95%CI: 2.2-18.5; P < 0.001) were significant risk factors for small bowel angioectasia.CONCLUSION: VFA is positively associated with theprevalence of small bowel angioectasia, for which VFA and liver cirrhosis are independent risk factors in patients with OGIB.

Chronic lung allograft dysfunction post-lung transplantation:The era of bronchiolitis obliterans syndrome and restrictive allograft syndrome

Chronic lung allograft dysfunction(CLAD)following lung transplantation limits long-term survival considerably.The main reason for this is a lack of knowledge regarding the pathological condition and the establishment of treatment.The consensus statement from the International Society for Heart and Lung Transplantation on CLAD in 2019 classified CLAD into two main phenotypes:Bronchiolitis obliterans syndrome and restrictive allograft syndrome.Along with this clear classification,further exploration of the mechanisms and the development of appropriate prevention and treatment strategies for each phenotype are desired.In this review,we summarize the new definition of CLAD and update and summarize the existing knowledge on the underlying mechanisms of bronchiolitis obliterans syndrome and restrictive allograft syndrome,which have been elucidated from clinicopathological observations and animal experiments worldwide.

Solid pseudopapillary neoplasm of the pancreas in a young male with main pancreatic duct dilatation: A case report

BACKGROUND Solid pseudopapillary neoplasms(SPNs)are rare tumors of the pancreas.Typically,they occur in young females,often have characteristic imaging features,such as cystic components and calcification,and have few effects on the pancreatic duct.CASE SUMMARY A 31-year-old man was admitted to our hospital with the chief complaint of epigastric pain.There was only mild tenderness in his upper abdomen,and blood tests showed only a slight increase in alkaline phosphatase.Contrast-enhanced computed tomography showed a 40-mm-diameter,hypovascular mass in the head of the pancreas,and the main pancreatic duct upstream of the mass was severely dilated.Magnetic resonance imaging showed low intensity on T1-weighted images,with high intensity on T2-weighted image in some parts.Pancreatic ductal adenocarcinoma was the primary differential diagnosis.Portal vein infiltration could not be ruled out,so this case was a candidate for neoadjuvant chemotherapy.Subsequently,endoscopic ultrasound-guided fine needle aspiration was performed,and pathological evaluation and immunostaining suggested a diagnosis of SPN.Thus,pancreatoduodenectomy was performed.One year after the operation,the patient is alive with no recurrence.CONCLUSION Main pancreatic duct dilatation is usually a finding of suspected pancreatic cancer.However,pancreatic duct dilatation can occur in SPN depending on the location and growth speed.Therefore,SPN should be considered in the differential diagnosis of tumors with pancreatic duct dilatation,and pathological evaluation by endoscopic ultrasound-guided fine needle aspiration should be actively performed.

The Effects of Insulin Resistance and Inflammation on Renal Proximal Tubule Sodium Transport and Hypertension

Insulin resistance, closely linked to inflammation, is recognized as a key factor in the onset and aggravation of diabetes, cardio-renal syndrome, hypertension, and obesity. In the renal proximal tubule, insulin resistance may increase renal sodium reabsorption, leading to hypertension, edema and sometimes heart failure. Recently some anti-diabetic agents have been shown to have effects on the transporters in renal proximal tubule. Because renal proximal tubule mediates about 70% of sodium reabsorption, it is quite important to clarify the function of renal proximal tubule under insulin resistance and inflammation.

Discussion about Improvement of Stability of the Scan Timing by Placing Small ROI in Cerebral 3D-CTA

In three-dimensional computed tomography angiography (3D-CTA) in our facility, we usually scan the volume of the brain according to the bolus tracking method. Fluoroscopic slice is placed at the Willis’s ring and the timing of scan is determined subjectively by a radiological technologist after strong enhancement of the basal cerebral artery is confirmed. In these procedures, however, variation of scan timing is often problematic. Therefore, we design the surpassing method to place the small region-of-interest (ROI) at the basal cerebral arteries and to start CT scan automatically. In this protocol, the fluoroscopic slices of the distal internal carotid arteries are selected referring to the precontrast volume data, small ROIs are set in bilateral internal carotid arteries, and scan trigger of CT is started automatically at the threshold of 170 HU. The maximum 80 mL of iodine contrast agent 300 mgI/mL is injected intravenously at the rate of 4.0 mL/sec, and the volume of the arterial phase is scanned automatically. We measure ROIs at the internal carotid arteries based on the obtained volume data of arterial phase and estimate the optimal scan timings from the fluoroscopic CT images reformatted at the intervals of 0.1 sec. In 38 of 53 patients, placement of the small ROIs is succeeded and automatic or manual CT scan is performed. In the patients who succeed in placement of the small ROIs, optimal scan timing of the arterial phase is obtained, while in the patients who fail placement of the small ROIs, a large variation is observed in their scan timings. Their results suggest that more stable scanning of the arterial phase is available by means of small ROI placement and automatic scanning. The clinical significance is large because the stability and reproducibility of the examination provide a quantitative analysis and more accurate diagnosis.

Preliminary Study on the Effectiveness of Different Durations of Hot Towel Application to the Back during Bed Bathing

The purpose of this study was to determine the most effective duration of hot towel application during bed bathing, based on temporal changes in skin surface temperature, towel temperature, and subjective comfort. As a secondary objective, differences in skin surface temperature and subjective comfort for hot towel application on the back and dry towel wiping alone were evaluated. For the first objective, hot towels were applied on the lower back of 20 healthy adults, for different duration (10, 15, and 20 s), with a 10-s duration found to be the most effective. For the second objective, we compared bed bathing with hot towel application to dry wiping alone, n 21 healthy adult participants. A 10-s hot towel application increased the surface temperature of the skin (+0.5℃) and provided a perceived sensation of warmth and comfort. In contrast, dry wiping significantly decreased the surface skin temperature (-0.8℃). In conclusion, hot towel application increased skin surface temperature and improved subjective warmth and comfort during bed bathing.

Apparent Diffusion Coefficient Mapping Using a Multi-Shot Spiral MRI Sequence of the Rat Brain

Purpose: Commonly used diffusion weighted (DW) imaging such as DW spin echo (SE) type echo planar imaging (DW-SE-EPI) is known to be a snapshot-like acquisition and to have a relatively high signal-to-noise ratio. Spiral MRI sequence (SPIRAL) has characteristics similar to these of EPI, but it has rarely been used for diffusion-weighted imaging (DWI). In vivo DW-SPIRAL of the rat brain has almost never been reported. Our purpose in this study was to examine the potential of SE-type two-dimensional (2D) multi-shot spiral acquisition MRI for apparent diffusion coefficient (ADC) mapping of the rat brain in vivo. Materials and Methods: We made an SE-type DW-2D-spiral MRI sequence (DW-SPIRAL) which was prepared on a 2.0-T animal-experiment MR scanner. Comparing the phantom experimental result of DW-SPIRAL with the phantom experimental result of DW SE-type echo-planar imaging (DW-SE-EPI) and conventional DW spin echo imaging (DW-SE), we estimated the characteristics of DW-SPIRAL and assessed the clinical application of DW-SPIRAL in an animal experiment on the rat brain. Results: There was not much difference between the calculated water/glycerol phantom diffusion coefficient of DW-SPIRAL and the calculated diffusion coefficient of DW-SE. This result shows that the DW-SPIRAL sequence is appropriate for use in diffusion weighted imaging. There were fewer phantom image distortions and ghosting artifacts with DW-SPIRAL than with DW-SE-EPI, and this tendency was similar in the animal experiment on the rat brain. Conclusion: The DW-SPIRAL sequence had been successfully tested in phantom experiments and rat brain experiments. It has been demonstrated that the DW-SPIRAL sequence is capable of producing in vivo rat brain DWI.

Effectiveness and safety of chemotherapy for patients with malignant gastrointestinal obstruction:A Japanese populationbased cohort study

BACKGROUND The impacts of chemotherapy on patients with malignant gastrointestinal obstructions remain unclear,and multicenter evidence is lacking.AIM To evaluate the effectiveness and safety of chemotherapy in patients with unresectable malignant gastrointestinal obstructions.METHODS We conducted a multicenter retrospective cohort study that compared the chemotherapy group who received any chemotherapeutics after interventions,including palliative surgery or selfexpandable metal stent placement,for unresectable malignant gastrointestinal obstruction vs the best supportive care(BSC)group between 2014 and 2019 in nine hospitals.The primary outcome was overall survival,and the secondary outcomes were patency duration and adverse events,including gastrointestinal perforation and gastrointestinal bleeding.RESULTS In total,470 patients in the chemotherapy group and 652 patients in the BSC group were analyzed.During the follow-up period of 54.1 mo,the median overall survival durations were 19.3 mo in the chemotherapy group and 5.4 mo in the BSC group(log-rank test,P<0.01).The median patency durations were 9.7 mo[95% confidence interval(CI):7.7-11.5 mo]in the chemotherapy group and 2.5 mo(95%CI:2.0-2.9 mo)in the BSC group(log-rank test,P<0.01).The perforation rate was 1.3%(6/470)in the chemotherapy group and 0.9%(6/652)in the BSC group(P=0.567).The gastrointestinal bleeding rate was 1.5%(7/470)in the chemotherapy group and 0.5%(3/652)in the BSC group(P=0.105).CONCLUSION Chemotherapy after interventions for unresectable malignant gastrointestinal obstruction was associated with increased overall survival and patency duration.

The Development and Implementation of the Maternal Mental Health Promotion Program for Expectant Mothers

Approximately 19% of women have minor or major depression in the first three months following delivery. The Maternal Mental Health Promotion Program is an intervention program designed to deliver during pregnancy to increase awareness and limits the effects of postpartum depression (PPD). The program was developed through a literature review and a focus group interview. It has three components (information on depressive symptoms during postpartum, reflecting on pregnancy, and the importance of good communication with one’s partner), delivered through lectures and group discussions using educational worksheets. The purpose of this paper was to describe the development, planning and implementing of an intervention program for expectant mothers to increase awareness and limits the effects of PPD. The program was evaluated by experienced midwives, and then delivered in antenatal classes where process evaluations were conducted. We confirmed that the objectives of the program were met and that the intervention was relevant to participants.

Relation between Family Functioning and Quality of Life among Family Caregivers of Patients with Terminal Cancer Hospitalized in General Wards

Caring for a patient with terminal cancer poses difficulties for family caregivers. Although families of patients with cancer have been classified by type, little is known about the relation between family functioning and quality of life (QOL) in family caregivers. This study aimed to develop a typology of family functioning in family caregivers of patients with terminal cancer and then examine the relation between the family functioning and QOL of family caregivers. From December 2013 to August 2014, fifty-one family caregivers of patients with terminal cancer were recruited at three hospitals in Tokyo, Japan. Perceptions of family functioning were assessed with the Family Relationship Index, and its three subscores were classified into three groups by cluster analysis. Caregivers’ QOL was measured with the Caregiver Quality of Life Index-Cancer. The average total FRI score among 51 caregivers was 8.5 (SD = 2.8). Family functioning was categorized into three clusters: supportive (n = 12), communicative (n = 30), or conflictive (n = 8). Their QOL was categorized into two groups: the communicative group, with relatively high confliction, showed high QOL comparable to the supportive group. Family functioning in the families of patients with terminal cancer hospitalized in general wards was not good. For improving the QOL of family caregivers, it may be important for the family members to express their feelings and distress if they have conflicts.

Current state of practice for colonic diverticular bleeding in 37 hospitals in Japan:A multicenter questionnaire study

AIMTo clarify the current state of practice for colonic diverticular bleeding(CDB)in Japan.METHODSWe conducted multicenter questionnaire surveys of the practice for CDB including clinical settings(8 questions),diagnoses(8 questions),treatments(7 questions),and outcomes(4 questions)in 37 hospitals across Japan.The answers were compared between hospitals with high and low number of inpatient beds to investigate which factor influenced the answers.RESULTSEndoscopists at all 37 hospitals answered the questions,and the mean number of endoscopists at these hospitals was 12.7.Of all the hospitals,computed tomography was performed before colonoscopy in 67%of the hospitals.The rate of bowel preparation was 46.0%.Early colonoscopy was performed within 24 h in 43.2%of the hospitals.Of the hospitals,83.8%performed clipping as first-line endoscopic therapy.More than half of the hospitals experienced less than 20%rebleeding events after endoscopic hemostasis.No significant difference was observed in the annual number of patients hospitalized for CDB between high-(&ge;700 beds)and low-volume hospitals.More emergency visits(P=0.012)and endoscopists(P=0.015),and less frequent participation of nursing staff in early colonoscopy(P=0.045)were observed in the high-volume hospitals.CONCLUSIONSome practices unique to Japan were found,such as performing computed tomography before colonoscopy,no bowel preparation,and clipping as first-line therapy.Although,the number of staff differed,the practices for CDB were common irrespective of hospital size.

Assessment of disease progression in patients with transfusion-associated chronic hepatitis C using transient elastography

METHODS： Between December 2006 and June 2008, a total of 524 transfusion-associated HCV-RNA positive patients with or without HCC were enrolled, Liver stiffness was obtained noninvasively by using Fibroscan （Echosens, Paris, France）, The date of blood transfusion was obtained by interview, Duration of infection was derived from the interval between the date of bloodtransfusion and the date of liver stiffness measurement （LSM）. Patients were stratified into four groups based on the duration of infection （17-29 years; 30-39 years; 40-49 years; and 50-70 years）. The difference in liver stiffness between patients with and without HCC was assessed in each group. Multiple linear regression analysis was used to determine the factors associated with liver stiffness.RESULTS： A total of 524 patients underwent LSM. Eight patients were excluded because of unsuccessful measurements. Thus 516 patients were included in the current analysis （225 with HCC and 291 without）. The patients were 244 men and 272 women, with a mean age of 67.8 ±9.5 years. The median liver stiffness was 14.3 kPa （25.8 in HCC group and 7.6 in non HCC group）. The patients who developed HCC in short duration of infection were male dominant, having lower platelet count, with a history of heavier alcohol consumption, showing higher liver stiffness, and receiving blood transfusion at an old age. Liver stiffness was positively correlated with duration of infection in patients without HCC （r = 0.132, P = 0.024） but not in patients with HCC （r = -0.103, P = 0.123）. Liver stiffness was significantly higher in patients with HCC than in those without in each duration group （P 〈 0.0001）. The factors significantly associated with high liver stiffness in multiple regression were age at blood transfusion （P 〈 0.0001）, duration of infection （P = 0.0015）, and heavy alcohol consumption （P = 0.043）CONCLUSION： Although liver stiffness gradually increases over time, HCC develops in patients with high stiffness value regardless of the duration of infection.

Functional coupling of V-ATPase and CLC-5

Dent’s disease is an X-linked renal tubulopathy characterized by low molecular weight proteinuria, hypercalciuria and progressive renal failure. Disease aetiology is associated with mutations in the CLCN5 gene coding for the electrogenic 2Cl-/H＋ antiporter chloride channel 5 （CLC-5）, which is expressed in the apical endosomes of renal proximal tubules with the vacuolar type H＋-ATPase （V-ATPase）. Initially identified as a member of the CLC family of Cl- channels, CLC-5 was presumed to provide Cl shunt into the endosomal lumen to dissipate H＋ accumulation by V-ATPase, thereby facilitating efficient endosomal acidification. However, recent findings showing that CLC-5 is in fact not a Cl- channel but a 2Cl-/H＋ antiporter challenged this classical shunt model, leading to a renewed and intense debate on its physiological roles. Cl- accumulation via CLC-5 is predicted to play a critical role in endocytosis, as illustrated in mice carrying an artifcial Cl- channel mutation E211A that developed defective endocytosis but normal endo-somal acidification. Conversely, a recent functional analysis of a newly identifed disease-causing Cl- channel mutation E211Q in a patient with typical Dent’s disease confrmed the functional coupling between V-ATPase and CLC-5 in endosomal acidifcation, lending support to the classical shunt model. In this editorial, we will address the current recognition of the physiological role of CLC-5 with a specific focus on the functional coupling of V-ATPase and CLC-5.

Case Report: Anaplastic Astrocytoma Treated with Postoperative Radiotherapy Using Flattening Filter-Free Volumetric Arc Therapy (FFF-VMAT) during Pregnancy—Acceptable Fetal Dosimetry

Background: Postoperative irradiation for brain tumor in pregnant women is a matter of concern. Aim: We aimed to assess the safety of radiotherapy for brain tumors in pregnancy. We here report a successful treatment for anaplastic astrocytoma during pregnancy: surgery + postoperative irradiation. We wish to emphasize how we devised irradiation procedure to achieve both therapeutic effectiveness and safety to the fetus/infant. Case Presentation: A 34-year-old pregnant woman suffered with brain anaplastic astrocytoma. Tumor resection under craniotomy was performed with success. We decided to conduct postoperative radiotherapy at 25 weeks of gestation to reduce the risk of recurrence. We used a flattening filter-free volumetric arc therapy (FFF-VMAT) technique, which can achieve lower out-of-field dose than VMAT with a flattening filter or helical tomotherapy. We prescribed 60 Gy over 30 fractions. During actual beam delivery, surface and rectal dose to the patient (mother) were measured. The total fetal dose was estimated at 0.006 - 0.018 Gy, which is under the threshold set by the ICRP. A male healthy infant was born vaginally at the 37th week of pregnancy. The patient (mother) and the infant are healthy at the time of writing. Conclusion: FFF-VMAT is a good choice for brain tumors during pregnancy.

The acid-base regulation by renal proximal tubule

The kidney plays quite an important role in the regulation of acid-base homeostasis. The dysfunction of renal acid-base regulation causes diseases such as developmental disorder, bone malformation, calcification of eye and brain, etc. In the kidney, this regulation is performed, to a considerable part, in the proximal tubule of the nephron. In the luminal side the key player is sodium-proton exchanger type 3 (NHE3), whereas sodium-bicarbonate cotransporter (NBCe1) plays the critical role in the basolateral side. In the cytoplasm there is carbonic anhydrase type 2 (CAII) that intermediates the conversion of CO2/ . Interestingly, in human, mutations have been found in NBCe1 and CAII but not in NHE3 so far. Mutations of NBCe1 lead to severe proximal renal tubular acidosis (pRTA) and other systemic manifestations. In animal model studies, however, the relative contribution of NHE3 to proximal tubule functions remains controversial. Recently, V-ATPase with renal specific subunits is suggested to have some roles in the regulation of proximal tubule functions. In this review, we will discuss the regulation of acid-base transport in the proximal tubule and the updates.

Hollow Fiber Module Applied for Effective Proliferation and Harvest of Cultured Chondrocytes

Steady and useful culture for chondrocytes is essential for cartilage regenerative medicine. However, in conventional plate culture, the chondrocytes become dedifferentiated and lose their ability to make cartilage matrices. Three-dimensional culture mimicking the physiological environment in native chondrocytes is useful to maintain the chondrocyte properties during the proliferation culture. However, the three-dimensional culture is practically a hard task due to difficult harvest of the cells. Thus, we attempted to apply porous materials, hollow fibers for the three-dimensional culture, and developed their module to realize the effective harvest of the cells. Polyethersulfone-based hollow fibers, whose safety and cell affinity were confirmed by the experiment of the coculture with human chondrocytes, were collected to fabricate a module. The hollow fiber module was installed with screw ends, and enabled the easy removal of chondrocytes from the inner unit. Cultured human chondrocytes embedded within collagen hydrogel were put into the outer lumen of the hollow fiber module, while chondrocyte prolfieration medium was perfused through the inner lumen at 0 to 30 mL/min. After 2 weeks’ culture, the flow rate of 3 to 10 mL/min effectively supported the chondrocyte proliferation. Then, long-term culture using the hollow fiber module at flow rate of 5 mL/min was performed, revealing that the cell growth in this module at 3 weeks was approximately twice larger than that in static culture. The numbers of viable cells could be maintained by week 7. The hollow fiber module installed with screw ends can effectively culture and harvest the chondrocytes.

Evaluation of <i>in vivo</i>migration of chondrocytes from tissue-engineered cartilage that was subcutaneously transplanted in mouse model

For regenerative medicine, clarification of in vivo migration of transplanted cells is an important task to secure the safety of transplanted tissue. We had prepared tissue-engineered cartilage consisting of cultured chondrocytes with collagen hydrogel and a biodegradable porous polymer, and we clinically applied it for treatment of craniofacial anomaly. To verify the safety of this tissue-engineered cartilage, we had syngenically transplanted the tissue-engineered cartilage using chondrocytes harvested from EGFP-transgenic mice into subcutaneous pocket of wild type mice, and investigated localizations of transplanted chondrocytes in various organs including cerebrum, lung, liver, spleen, kidney, auricle, gastrocnemius, and femur. After 8 to 24 weeks of the transplantation, accumulation of cartilaginous matrices was observed in tissue-engineered cartilage, while EGFP-positive transplanted chondrocytes were localized in this area. Otherwise, no EGFP was immunohistochemically detected in each organ, suggesting that subcutaneously-transplanted chondrocytes do not migrate to other organs through the circulation. In cartilage tissue engineering using cultured chondrocytes, risk for migration and circulation of transplanted cells seemed negligible, and that ectopic growth of the cells was unlikely to occur, showing that this is safe technique with regard to the in vivo migration of transplanted cells.

Behavioral and Neural Enhancing Effects of a Summer Treatment Program in Children with Attention Deficit Hyperactivity Disorder

Deficiency in executive functioning is a core symptom of attention deficit hyperactivity disorder (ADHD). The brain part responsible for executive functions is the prefrontal cortex (PFC). Although drug-based interventions can improve PFC activity, reports on PFC activity being improved by behavioral treatment are lacking. We evaluated whether a summer treatment program (STP) administering comprehensive behavioral treatment would increase PFC activity in children with ADHD. We examined behavioral and neural changes in 20 children before and after the STP, conducted over a 2-week period. We asked the parents/guardians to complete the Swanson, Nolan, and Pelham IV scale to assess severity of ADHD. The main task evaluating executive control was the reverse Stroop task. To examine changes in physiological indices, we used near-infrared spectroscopy to measure changes in PFC activity. Subjective assessments by parents/guardians indicated that ADHD symptoms improved significantly. There was also significant improvement in the number of correct responses and interference rates in the reverse Stroop task. Furthermore, post-intervention PFC activity was significantly higher. These results suggest that the STP improved inhibitory control in executive function, which is considered as a key symptom of ADHD. The increase in PFC activity further suggests that the STP improves cognition through neural function.

Usefulness of Agarose Mold as a Storage Container for Three-Dimensional Tissue-Engineered Cartilage

The efficiency of substance exchange may be decreased when the thickness and volume of such a tissue-engineered cartilage that is composed of cultured cells and porous scaffold increase. Moreover, during the transport of this construct with complicated shapes, excessive and focal mechanical loading may cause deformation. The establishment of incubation and transport methods is necessary for the three-dimensional tissue-engineered cartilage. Therefore, we investigated the preparation of an agarose mold with a concavity similar to the shape of 3-dimensional tissue-engineered cartilage to prevent excessive and focal concentration of stress, while avoiding interference with substance exchange as much as possible. Firstly, we investigated the preparation at 1% - 4% agarose concentrations. Since the mechanical strength was insufficient at 1%, 2% was regarded as appropriate. Using 2% agarose, we prepared a mold with a 5 × 5 × 5 mm concavity to accommodate tissue-engineered cartilage (5 × 5 × 5 mm mixture of 1.5 × 107 cells and collagen gel), and stored the regenerative cartilage in it for 2 and 24 hours. On comparison with storage in a plastic mold with the same shape in which substance exchanged from side and bottom was impossible, although no significant differences were noted in the number or viability of cells after 2 hours, these were markedly reduced in the plastic mold after 24 hours. It was confirmed that favorable cell numbers and viability were maintained by immediately retaining the regenerative cartilage in the culture medium in the agarose mold and keeping the temperature at 37°C. Since this agarose mold also buffers against mechanical forces loaded on the three-dimensional regenerative tissue, it may be useful as a container for storage and transport of large-sized three-dimensional regenerative tissue.

Real-time in situ three-dimensional integral videography and surgical navigation using augmented reality: a pilot study

To evaluate the feasibility and accuracy of a three-dimensional augmented reality system incorporating integral videography for imaging oral and maxillofacial regions, based on preoperative computed tomography data. Three-dimensional surface models of the jawbones, based on the computed tomography data, were used to create the integral videography images of a subject＇s maxillofacial area. The three-dimensional augmented reality system （integral videography display, computed tomography, a position tracker and a computer） was used to generate a three-dimensional overlay that was projected on the surgical site via a half-silvered mirror. Thereafter, a feasibility study was performed on a volunteer. The accuracy of this system was verified on a solid model while simulating bone resection. Positional registration was attained by identifying and tracking the patient/surgical instrument＇s position. Thus, integral videography images of jawbones, teeth and the surgical tool were superimposed in the correct position. Stereoscopic images viewed from various angles were accurately displayed. Change in the viewing angle did not negatively affect the surgeon＇s ability to simultaneously observe the three-dimensional images and the patient, without special glasses. The difference in three-dimensional position of each measuring point on the solid model and augmented reality navigation was almost negligible （〈1 mm）; this indicates that the system was highly accurate. This augmented reality system was highly accurate and effective for surgical navigation and for overlaying a three-dimensional computed tomography image on a patient＇s surgical area, enabling the surgeon to understand the positional relationship between the preoperative image and the actual surgical site, with the naked eye.