Islet purification method using large bottles effectively achieves high islet yield from pig pancreas

Porcine islets are a promising resource for xenotransplantation. However, low efficacy of islet isolation because of their marked fragility remains a problem. Recently we found that the standard purification method using COBE 2991 cell processor (COBE) with Ficoll density gradient solution damaged islets mechanically by high shearing force. In this study, we evaluated our new purification method using large plastic bottles for the efficacy of islet purification. Ten porcine pancreata were used. The average warm ischemic time was over 40 min; therefore, these pancreata were considered to be in a marginal condition. After digestion, the digested tissue was divided into three groups. Each group was purified using either top loading method with bottle (top group) or bottom loading method with bottle (bottom group) or standard COBE method (COBE group). Islet yield per pancreas weight (IEQ/g) and the rate of postpurification recovery in the top group were significantly higher than the COBE group (top: 8060 ± 1652 IEQ/g, bottom: 4572 ± 614 IE/g, COBE: 3900 ± 734 IE/g. p < 0.02 in top vs. COBE; top percentage of recovery: 99.3 ± 12.3%, bottom: 62.6 ± 8.8%, COBE: 49.5 ± 6.7%, p < 0.02 in top vs. bottom and COBE). The average sizes of purified islets in the top and bottom groups were significantly larger than COBE group (Average diameter top: 156 ± 8 μm, bottom: 147 ± 6 μm, COBE: 119 ± 6 μm, p < 0.01 in top vs. COBE and in bottom vs. COBE), which indicated that bottle method can reduce shear force during purification. Our new purification using top loading bottle method enabled us to obtain a high yield of porcine islets from marginal pancreata.     

Comparison of ulinastatin, gabexate mesilate, and nafamostat mesilate in preservation solution for islet isolation

For islet transplantation, maintaining organ viability after pancreas procurement is critically important for optimal graft function and survival. We recently reported that islet yield was significantly higher in the modified ET-Kyoto (MK) solution, which includes a trypsin inhibitor (ulinastatin), compared with the UW solution, and that the advantages of MK solution are trypsin inhibition and less collagenase inhibition. In this study, we compared ulinastatin with other trypsin inhibitors, gabexate mesilate, and nafamostat mesilate, in preservation solution for islet isolation. Ulinastatin was easily dissolved in ET-Kyoto solution, while ET-Kyoto with gabexate mesilate and nafamostat mesilate became cloudy immediately after addition. Although there were no significant differences in islet yield among the three groups, viability was significantly higher for the MK group than for the GK group or the NK group. The stimulation index was significantly higher for the MK group than for the GK group. In summary, there are no other trypsin inhibitors that are more effective than ulinastatin. Based on these data, we now use ET-Kyoto solution with ulinastatin for clinical islet transplantation.     

Liver sinusoidal endothelial cells have a capacity for inducing nonresponsiveness of T cells across major histocompatibility complex barriers

Livers transplanted across major histocompatibility complex (MHC) barriers in mice are normally accepted without recipient immune suppression. To identify the cell type that contributes to induction of such a tolerance state, we established an allogeneic mixed hepatic constituent cell-lymphocyte reaction (MHLR) assay. Hepatic constituent cells were isolated from C57BL/6 (B6) and Balb/c mice as stimulators, and splenocytes were isolated from B6 mice as responders. Irradiated hepatic constituent cells were co-cultured with fluorescent dye (CFSE)-labeled B6 splenocytes. In the allogeneic MHLR using either whole hepatic constituent cells or parenchymal hepatocytes as stimulators, a lack of T-cell proliferation was observed. Only when CD105(+) cells, which are exclusively liver sinusoidal endothelial cells (LSECs), were depleted from hepatic constituent cell stimulators, the MHLR resulted in marked proliferation of both allo-reactive CD4(+) and CD8(+) T cells. These results indicate that CD105(+) LSECs have the capacity to induce nonresponsiveness of T cells across MHC barriers.     

Triangle target principle for the placement of trocars during video-assisted thoracic surgery.

OBJECTIVE: The baseball-diamond principle is generally used for trocar placement during video-assisted thoracic surgery; however, we are unable to treat all peripheral lung lesions using this principle. Therefore, we have developed another method for determining trocar placement based on a modification of the conventional principle. We have termed this method the triangle target principle. This report describes the instrument positioning that we now use for many video-assisted thoracic surgical procedures. METHODS: We position 3 trocars in an equilateral triangle, with the target lesion at the apex. One vertex of the base becomes the site of the first trocar placement for introduction of the thoracoscopic camera. Another vertex of the base becomes the site for the second trocar for forceps or the endoscopic stapler. The third trocar is for forceps and is inserted to create the vicinity of target lesion. Four types of the triangle target principle were developed according to sites of the target lesion. RESULTS: Between January 2000 and December 2002, we used this principle for 161 patients who underwent video-assisted thoracic surgery and all intrathoracic lesions were accessible except in 3 patients requiring intraoperative modifications. CONCLUSIONS: We conclude that video-assisted thoracic surgery by this principle is more effective and easier than the conventional principle to treat intrathoracic disease.     

Cross-modal binding and activated attentional networks during audio-visual speech integration: a functional MRI study

We evaluated the neural substrates of cross-modal binding and divided attention during audio-visual speech integration using functional magnetic resonance imaging. The subjects (n = 17) were exposed to phonemically concordant or discordant auditory and visual speech stimuli. Three different matching tasks were performed: auditory-auditory (AA), visual-visual (VV) and auditory-visual (AV). Subjects were asked whether the prompted pair were congruent or not. We defined the neural substrates for the within-modal matching tasks by VV-AA and AA-VV. We defined the cross-modal area as the intersection of the loci defined by AV-AA and AV-VV. The auditory task activated the bilateral anterior superior temporal gyrus and superior temporal sulcus, the left planum temporale and left lingual gyrus. The visual task activated the bilateral middle and inferior frontal gyrus, right occipito-temporal junction, intraparietal sulcus and left cerebellum. The bilateral dorsal premotor cortex, posterior parietal cortex (including the bilateral superior parietal lobule and the left intraparietal sulcus) and right cerebellum showed more prominent activation during AV compared with AA and VV. Within these areas, the posterior parietal cortex showed more activation during concordant than discordant stimuli, and hence was related to cross-modal binding. Our results indicate a close relationship between cross-modal attentional control and cross-modal binding during speech reading.     

Age estimation by quantitative features of pubic symphysis using multidetector computed tomography

Macroscopic assessment of the pubic symphysis is commonly used for age estimation because its surface changes over time. However, postmortem computed tomography (PMCT), a method several forensic medical departments and institutes have begun to adopt, has the potential to simplify the information gathering process from the pelvic bone without requiring soft tissue removal. Some studies have previously evaluated the use of three-dimensional images of the pubic symphysis, but because of variance in the graphics processing among image analysis software packages, certain differences have been observed between these studies. Therefore, in this study, the PMCT findings of 199 subjects of known age and sex were retrospectively reviewed to examine the feasibility of age estimation using planar images of the pubic bones and soft tissue. The coronal and axial sectional images were observed at the center of the symphyseal surface, and the pubic bone length and thickness of the connective tissue of the pubic symphysis were measured at each slice. Our results revealed a significant positive correlation between the length of the pubic bone of the coronal section and age, suggesting that the use of a cutoff value for pubic bone length might be feasible for age estimations. In addition, the thickness of the connective tissue tended to narrow over time. Although the prediction interval range of planar images obtained by PMCT was major and is not usable in practice at this moment, it may still be a useful tool if used in conjunction with other findings obtained by PMCT.     

Guidelines on the use of gelatin sponge particles in embolotherapy

Gelatin sponge (GS) is one of the most widely used embolic agents in interventional procedures. There are four commercially available GS products in Japan; however, the endovascular use of Gelfoam and Spongel is off-label, and Gelpart can only be used for hepatic artery embolization and Serescue can only be used for hemostasis of arterial bleeding. GS has been used for a variety of clinical indications, mainly tumor embolization and stopping massive arterial bleeding. The optimal size and preparation procedure of GS particles differs slightly for each clinical indication. In addition, there is a risk of ischemic and/or infectious complications associated with GS embolization in various situations. Therefore, radiologists should be familiar with not only the preparation and handling of GS particles, but also the disadvantages and potential risks, in order to perform GS embolization safely and effectively.