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M Sasaki

Publications and source records attributed to M Sasaki.

At least 37 records · Page 2Linked to original sources
PubMed2005

Structure and property of self-assemble valinyl bolaform amides having different chirality.

Bolaform amides were designed from N,N'-bis(carboethoxy-L-valinyl)-diaminoethane (1) by linking t-butyloxycarbonyl-valine through ethylenediamine (EDA) to enable spectroscopic and X-ray diffraction analyses. N,N'-Bis(Boc-L-valinyl)-diaminoethane (2) and N,N'-bis(Boc-D-valinyl)-diaminoethane (3) were composed of L-Val and D-Val, respectively. N-(Boc-L-valinyl)-N'-(Boc-D-valinyl)-diaminoethane (4) was composed of both L-Val and D-Val, and was achiral (meso-peptide). Peptide 5 was a 1:1 mixture of 2 and 3, and was also achiral (racemate). These peptides mediated gelation of corn oil at a concentration of approximately 1%. Within crystals, the peptides formed beta-sheet ribbons, but differences were observed in hydrogen-bonding patterns and side-chain arrangements. These differences were also deduced from temperature dependence of amide protons. Force-field calculations based on the crystal structures indicated that association of beta-sheet ribbons had energy benefits, and it was assumed that molecular aggregation progressed spontaneously. These structural studies indicated the chirality of amino acids affected for the properties of bolaform amides.

Amides↗
PubMed2005

Immunohistochemical localization of gastrin-releasing peptide, neuronal nitric oxide synthase and neurone-specific enolase in the uterus of the North American opossum, Didelphis virginiana.

The present study has demonstrated the immunohistochemical localization of gastrin-releasing peptide (GRP), neuronal nitric oxide synthase (nNOS) and neurone-specific enolase (NSE) in the uterus of the North American opossum. Although the presence of GRP, nNOS and NSE has been reported recently in the uterus of eutherian species this is the first description of these peptides in a metatherian species. Metatherian mammals are of interest because in these species it is the prolonged lactation phase of development that is the period of primary reproductive investment rather than intrauterine development as is true of eutherian mammals. The opossum, like other marsupial species, has a very abbreviated gestation period which in Didelphis lasts only 12.5 days. GRP was localized in the cytoplasm of cells forming the surface lining epithelium and the glandular epithelium of the opossum endometrium late in pregnancy, at 11.5 days of gestation. Likewise, immunoreactivities of nNOS and NSE were found primarily within the epithelial cells of the endometrium at 11.5 days of gestation. As these peptides and enzymes appear primarily at the time of establishment of the yolk sac placenta (between day 10 and day 12.5 gestation), the present results strongly suggest that these factors may play a fundamental role in the placentation of the opossum.

Animals↗
PubMed2005

Immunohistochemical study on the distribution and relative frequency of endocrine cells in the stomach of the Malayan Pangolin, Manis javanica.

The distribution and relative frequency of six kinds of endocrine cells in the stomach of the Malayan pangolin, Manis javanica were studied immunohistochemically using the avidin-biotin-peroxidase complex method. The stomach of the pangolin has three regions of mucous gland, one oxyntic gland and one pyloric gland. Cells immunoreactive for chromogranin, serotonin, somatostatin, BPP and glucagon were detected in all of the gastric glands, while gastrin-immunoreactive cells were found in the entire gastric gland except for the oxyntic gland. The distribution pattern of endocrine cells in the mucous gland and pyloric gland was mainly from the middle to apical portions of the glands. The endocrine cells were rare or not detected in the basal portion of all of the mucous glands and pyloric gland, but they were also found in the basal portion of the oxyntic gland. The distribution pattern of the endocrine cells in the mucous and pyloric glands suggested that this position facilitates a quick response to the luminal ingesta. The wide distribution of gastrin-immunoreactive cells in all of the mucous glands and pyloric gland was the most remarkable finding. This distribution suggests a major function of gastrin-immunoreactive cells for the digestive process in the Malayan pangolin stomach.

Animals↗
PubMed2005

Streptococcus anginosus infection in oral cancer and its infection route.

OBJECTIVE: To elucidate a possible involvement of Streptococcus anginosus in oral cancer, we assessed the frequency of S. anginosus infection in oral cancer tissues, and investigated its infection route. MATERIALS AND METHOD: The tissue specimens were obtained from 46 oral cancer and three precancerous leukoplakia subjects. Frequency of S. anginosus infection was assessed by a species-specific polymerase chain reaction (PCR) assay. The genotype of the clinical isolates taken from cancer tissue and dental plaque samples was analyzed using pulsed-field gel electrophoresis (PFGE). RESULTS: S. anginosus DNA was frequently detected in squamous cell carcinoma (19/42), but not in other types of cancer (lymphoma and rhabdomyosarcoma) or leukoplakia samples. A subject-based analysis revealed that S. anginosus was solely detected in dental plaque and not in saliva from all 19 S. anginosus-positive squamous cell carcinoma cases. Further, the genotype of S. anginosus isolated from cancer tissue was identical to that from dental plaque of the same patients. CONCLUSION: Infection of S. anginosus could occur frequently in oral squamous cell carcinoma and that dental plaque could be a dominant reservoir of the S. anginosus.

Aged↗
PubMed2004

Measurement of the flux of ultrahigh energy cosmic rays from monocular observations by the High Resolution Fly's Eye experiment.

We have measured the cosmic ray spectrum above 10(17.2) eV using the two air-fluorescence detectors of the High Resolution Fly's Eye observatory operating in monocular mode. We describe the detector, phototube, and atmospheric calibrations, as well as the analysis techniques for the two detectors. We fit the spectrum to a model consisting of galactic and extragalactic sources.

Journal Article↗
PubMed2004

Ultrastructural localization of gastrin-releasing peptide (GRP) in the uterine gland of cow.

Gastrin-releasing peptide (GRP) is thought to act mainly as a neurotransmitter and localized almost exclusively to neurons and neuroendocrine cells. Recently, the localization of GRP in mammalian uterus and placenta has been demonstrated. Moreover, the exocrine manner of GRP release was deduced in ewes from the distribution of GRP on the uterine gland cells and its secretion as well as in the circulation. However, these reports have been examined at light-microscopic level. The present study was designed to make clear the localization of GRP in the uterine gland cells of nonpregnant and pregnant cows using an avidin-biotin-peroxidase complex (ABC) method at light-microscopic level and a pre-embedding immunogold with silver enhancement method at electron-microscopic level. The light-microscopic observation showed positive staining for GRP immunoreactivity in the supranuclear region and in the secreted materials of the uterine gland cells. At the electron-microscopic level, the supranuclear secretory granules and the secreted materials on the surface of the cell were labeled with immunogold particles representing GRP immunoreactivity in the uterine gland cells of nonpregnant and pregnant cows. Western blotting analysis showed a larger molecular form of GRP in the endometrial tissues taken from nonpregnant and pregnant cows. The present results revealed the localization of GRP in the uterine gland cells at light- and electron-microscopic levels and suggested the release of GRP from the cell into the lumen of the gland by exocrine manner.

Animals↗
PubMed2004

Clinical surveillance of surgical imipenem-resistant Pseudomonas aeruginosa infection in a Japanese hospital.

In order to elucidate any changes in imipenem-resistant Pseudomonas aeruginosa (IRPA) infections in Japan, we examined 511 P. aeruginosa stains isolated from our surgical ward between 1987 and 2001. These isolates were subjected to susceptibility testing against various antipseudomonal agents including imipenem, meropenem, ceftazidime, gentamicin and ciprofloxacin. They were serotyped with the slide agglutination test and genotyped using pulsed-field gel electrophoresis (PFGE). The annual incidences of IRPA infections were particularly high in the early 1990s. Epidemiological investigations revealed that these outbreaks were due to dissemination of hospital-acquired IRPA isolates. Intensive use of imipenem promoted the selection of highly resistant strains. Further study of resistance mechanisms revealed that none of the 110 IRPA strains were metallo-beta-lactamase (MBL) producers. Polymerase chain reaction (PCR) analysis using bla(IMP) specific primers confirmed that no IMP-1 type MBL gene-positive strains were detected from our ward. Susceptibilities of those IRPA strains against other antipseudomonal agents showed relatively low levels, suggesting that imipenem resistance was mainly due to impermeability of the OprD porin. In conclusion, hospital-acquired outbreaks of IRPA were recently reduced by guidelines for, and surveillance of, appropriate use of antimicrobial agents. When the rate of IRPA isolation increases, serotyping should be performed initially and PFGE is required to confirm outbreaks. A computer-assisted genotyping technique is available to perform epidemiological studies of IRPA isolates.

Anti-Bacterial Agents↗
PubMed2004

Efficacy of double-filtration plasmapheretic cross-circulation with a high-permeability membrane using canine harvested liver in porcine fulminant hepatic failure model.

INTRODUCTION: The use of bioartificial liver devices requires. A sufficient liver cell mass to provide adequate metabolic support, reduction of xenogeneic immune reactions, and avoidance of viral transmission. We have developed a plasmapheresis system using a semipermeable membrane combined with canine whole liver perfusion (PMCWLP). In this study, we investigated the efficacy of our system in a porcine fulminant hepatic failure (FHF) model. METHODS: The porcine FHF model was established by intraportal administration of alpha-amanitin (0.1 mg/kg) and lipopolysaccharide (1 microg/kg). Nine hours after drug injection, xenogenic perfusion treatment was performed twice within 6 hours (n = 5). As the plasmapheresis device, we used a hollow-fiber module with cellulose diacetate porous fibers (pore size, 0.05 microm, surface area, 2 m2). The canine whole liver was perfused with modified Krebs solution, which is commonly used in many laboratories, containing albumin (2 g/dL) and glucose (300 mg/dL). Control pigs (n = 10), had the circuit not connected to the whole canine liver. RESULTS: The survival of FHF pigs was significantly increased by the treatment (58.9 +/- 21.8 hour) compared with the controls (22.3 +/- 8.1 hour). Mean blood ammonia levels and intracranial pressure during treatment were significantly lower compared with control groups. CONCLUSION: Treatment of FHF pigs with the system significantly increased survival time, suggesting that this method may have applications as a clinical liver assist device.

Animals↗
PubMed2004

Primary immunosuppression regimen of rapid steroid withdrawal after living related liver transplantation: a single-center experience.

AIM: Corticosteroids have been considered the mainstay of immunosuppressive therapy after liver transplantation. However, the side effects of long-term steroid use such as diabetes, infections, and bone disease, including growth retardation in children, are serious problems. Our immunosuppression regimen includes FK506 and steroid withdrawal by 30 days after transplantation. The aim of this study was to determine the outcomes of liver transplant, using this immunosuppressive regimen. PATIENTS: Fifteen primary liver transplant recipients were performed between January 1994 and May 2003 and data were reviewed retrospectively. Eight pediatric and four adult recipients, who had survived more than 3 months after transplantation, were included in this sample. The immunosuppressive regimen consisted of FK 506 (Prograf), initially at doses of 0.03 mg/kg, with dose adjustments to achieve daily trough levels of approximately 10 to 12 ng/mL, and predonisone, initially at 4 mg/kg/d, with a taper and cessation by 30 days when the graft was stable. RESULTS: All recipients were successfully withdrawn by 30 days. Acute rejection episodes occurred in three patients, no patient was diagnosed with chronic rejection. The acute rejection-free rate at 5 year was 74.1%. No recipient had diabetes, serious infections or bone disease. CONCLUSION: Our primary immunosuppressive regimen of rapid steroid withdrawal is safe with regard to acute and chronic rejection with benefits upon steroid-related side effects.

Adolescent↗
PubMed2004

In vitro evaluation of cross-circulation system using semipermeable membrane combined with whole liver perfusion.

INTRODUCTION: Many types of isolated hepatocytes-based bioartificial liver have been developed. However, to maintain hepatocyte-specific functions for a long period is still a significant challenge. The possibilities of rejection or viral transmission still remain as untackled obstacles. We developed a cross-circulation system, using a semipermeable membrane combined with whole liver perfusion. Detoxifying functions of the extracorporeal porcine liver and molecular movements across the membrane were evaluated in vitro. METHODS: The hollow-fiber module has a molecular cutoff of 100 kD. A spiked solution containing 500 mL low molecular dextran solution spiked with 12 mg ammonium chloride, 500 mg D-galactose, and 300 mg lidocaine, which mimicked a patient, was recirculated through the inner fiber space. The extracorporeal liver perfusion circuit consisted of an extra-fiber spaces. A reservoir containing 1000 mL healthy pig plasma, a membrane oxygenator, and a porcine whole liver. Both circuits circulated in the opposite direction for 6 hours. RESULT: In 6 hours, 47.3% +/- 10.2% of ammonia, 89.5% +/- 1.7% of D-galactose, and 95.5% +/- 1.0% of lidocaine were eliminated from the circuits; 66.5 +/- 11.1 mg of urea were produced at the same time. Oxygen consumption was maintained between 0.248 and 0.259 mL/100 g liver/min for 6 hours. Movement of IgM was completely blocked by the 100-kD membrane, whereas albumin was freely transferred from the reservoir to the intrafiber space. CONCLUSION: The perfusion experiments showed the possibility of using a whole liver with oxygenated plasma perfusion in a bioartificial liver system in vitro.

Animals↗
PubMed2004

CD8 T cell of donor splenocyte mixed with bone marrow cells is more effective than CD4 T cell for induction of donor-specific tolerance in sublethally irradiated mice.

BACKGROUND: We previously demonstrated that even a low dose of bone marrow cells (BMCs) established donor-specific tolerance if mixed with splenocytes (SPLCs). In this study, T-cell subsets CD4 (CD4SP) and CD8 (CD8SP) of donor SPLCs were investigated for their contribution to the enhancement of BMC engraftment leading to donor-specific tolerance in sublethally irradiated mice. METHODS: Sublethally irradiated C57BL/6 recipient mice were intravenously injected BMCs mixing with CD4SP or CD8SP harvested from BALB/c donor mice. The degree of chimerism in the peripheral blood lymphocytes (PBLs) and in the SPLCs was analyzed using FACS, mixed lymphocyte reaction, and skin graft transplantation 3 months after injection. RESULTS: Recipients injected with 3 x 10(6) donor BMCs admixed with 10 x 10(6) donor CD8SP established chimerism. However, recipients injected with the same dose of BMCs admixed with 5 x 10(6) CD4SP, 10 x 10(6) CD4SP, and 5 x 10(6) CD8SP did not established chimerism. CD8SP contained 44% of Ly6A/E (Stem Cell Antigen-1 (Sca-1))-positive cells based on FACS analysis, whereas only 6% of CD4SP were positive for Ly6A/E. MLR supernates of donor SPLCs chimeric mice using admixture with CD8SP dominated by Th2 cytokines. In contrast, mixting with MLR supernates from failed chimera showed dominant Th1 cytokines. CONCLUSIONS: CD8SP seems to make a major contribution to enhance BMC engraftment and induce donor-specific tolerance. Ly6A/E (Sca-1)-positive cells need to be further investigated for their contribution to the establishment of chimerism.

Animals↗
PubMed2004

A new method to immortalize primary cultured rat hepatocytes.

BACKGROUND: In conventional methods of establishing hepatocyte cell lines, the immortalizing gene alone is introduced into hepatocytes. We designed a new method in which not only the immortalizing gene, the simian virus-40 large T-antigen (SV-40 Tag) gene, but also a drug-resistant gene, under the control of an albumin enhancer/promoter, were introduced into hepatocytes to efficiently obtain immortalized hepatocyte cell lines. METHODS: The plasmid pAPUR contains the puromycin-resistant gene under the control of an albumin enhancer/promoter, and the pSVTag contains the early region of SV-40 enhancer/promoter and the SV-40 Tag gene. Both pAPUR and pSVTag were transferred into isolated rat hepatocytes by electroporation. After these cells were cultured on a collagen-coated dish for 24 hours, puromycin selection was started. Expression levels of albumin, alpha-fetoprotein (AFP), SV-40 Tag, and cytokeratin 19 (CK 19) in the transformed cells were evaluated by western analysis, immunocytochemical staining, and RT PCR. RESULTS: Approximately 3 weeks after transfection, five or six colonies appeared on the dish. Twenty strains were obtained by cloning these cells. All strains that were similar to immature hepatocytes expressed albumin and SV-40 Tag, although CK 19 was not detected. AFP expression was detected in 33% of these strains. CONCLUSIONS: All clones cotransfected by pAPUR and pSVTag expressed albumin. Our new method may be useful to establish hepatocyte cell lines.

Animals↗
PubMed2004

Intraoperative blood lactate level as an early predictor of initial graft function in human living donor liver transplantation.

UNLABELLED: This study was performed to investigate whether intraoperative changes in blood lactate levels after hepatic allograft reperfusion reflect initial graft function in living donor liver transplantation (LDLT). PATIENTS AND METHODS: From 1994 to 2003, 15 of LDLT cases were divided into two groups based on the intraoperative blood lactate levels. Group A consisted of seven recipients whose new liver grafts started to consume lactate immediately after portal perfusion. Group B consisted of the remaining eight recipients whose intraoperative blood lactate values showed no change or an elevation for 2 hours after graft revascularization. RESULTS: All Group A patients survived, whereas three out of eight patients in Group B died of infection and portal vein thrombosis within 3 months after LDLT. There was no significant difference in preoperative donor and recipient laboratory data. The recipient age and body size in Group B were significantly higher than those in Group A, indicating that Group B consisted of small-for-size liver transplant cases. Serum total bilirubin concentrations in Group B were significantly higher than Group A from postoperative day 5 to 23, whereas postoperative liver enzyme levels and prothrombin time were similar between the two groups. CONCLUSION: The change in intraoperative blood lactate after hepatic allograft reperfusion served as an accurate predictor of initial graft function which was associated with graft size in human LDLT.

Adult↗
PubMed2004

Analysis of clinical variables of donors and recipients with respect to short-term graft outcome in human liver transplantation.

UNLABELLED: Donor and recipient factors are closely associated with graft survival after orthotopic liver transplantation (OLT). This study was performed to analyze clinical characteristics of recipients and donors, which affect 30-day graft loss after OLT. MATERIALS AND METHODS: One hundred eighty-six livers from heart-beating donors were accepted between May 1997 and June 1998 at the University of Pittsburgh Medical Center. Donor variables that were analyzed included age, sex, cold ischemia time (CIT), warm ischemia time (WIT), imported versus local procurement, cardiopulmonary arrest, serum sodium level, and dopamine dose. The recipient characteristics included native liver disease and UNOS status. Two-sided Fisher exact test and stepwise logistic regression were used for univariate and multivariate analyses. P-values < .05 were considered statistically significant. RESULTS: Twenty-eight grafts (15.1%) were lost within 30 days of OLT. The following factors were found to adversely affect graft survival: donor sodium > 155 mEq/L (P = .002); CIT > 12 hours (P = .002); WIT > 45 minutes (P = .002); and imported liver graft (P = .048). Logistic regression revealed that donor sodium (odds ratio, 3.03; 95% CI, 1.05 to 8.74), CIT (OR 1.20; 95% CI 1.05 to 1.38), WIT (OR 1.06; 95% CI 1.01 to 1.09) were independent predictors of early graft loss. CONCLUSION: Donor hypernatremia as well as warm and cold ischemia times independently affect graft outcomes in the early postoperative period after OLT. Avoidance of long preservation and correction of donor sodium level are recommended to optimize results and survival in OLT.

Cause of Death↗
PubMed2004

Hepatic vein anastomotic stricture after living donor liver transplantation.

This report discusses the pathophysiology of and therapeutic methods to address hepatic vein anastomotic stricture after living donor liver transplantation (LDLT). From 1994 to 2002, our 15 LDLTs using the lateral segments or left lobes included four recipients who experienced 28 occurrences of this complication after the operation. The period between LDLT and the first stricture was 4.0 +/- 1.2 months. The age of the affected recipients (31.0 +/- 8.2 years) was significantly higher than that of the nonaffected patients (7.0 +/- 4.1 years, P < .05). Graft liver/standard liver volume ratio was 39.1% +/- 3.8% in the former and 77.9% +/- 12.7% in the latter cases (P < .05). Initial symptoms of stricture were ascites (42.9%), abdominal distention (42.9%), liver enzyme elevation (10.7%), and gastrointestinal bleeding (3.6%). In addition, 14 of 28 stricture cases (50%) showed increased blood trough levels of tacrolimus. Doppler ultrasonography was used for diagnosis, and balloon dilatations performed in all stricture patients, thereby hepatic significantly reducing venous blood pressure from 33.5 +/- 1.7 to 20.3 +/- 1.5 cmH2O. All patients finally resolved the strictures after several treatments. The stricture after LDLT was associated with small-for-size grafts, suggesting that liver regeneration may lead to anatomical changes and strictures. Since tacrolimus is metabolized by the liver, its blood trough level is one initial symptoms of stricture. Balloon dilatation was useful and safe as the treatment, while problems have been reported after stent insertion in the hepatic vein.

Adult↗
PubMed2004

Attenuation of canine warm ischemic small bowel injury by novel combination of nitric oxide donor, FK409, and cytokine suppressive anti-inflammatory agent FR167653.

Organ ischemia-reperfusion injury is caused by two consecutive steps, microcirculatory disturbance and neutrophil-endothelial cell interactions, which are caused by inflammatory cytokines. We examined the hypothesis that combination therapy with a donor (FK409) of nitric oxide, one of the potent mediators with diverse roles as a vosodilator and a platelet inhibitor, together with the cytokine suppressor agent (FR167653) attenuates warm ischemic injury in canine small bowel. Small bowel ischemia was initiated by clamping the superior mesenteric artery and vein. Animals were divided into two groups: a control group (n = 5) subjected to 2-hour small bowel ischemia only, and a combination therapy group (FK/FR group, n = 5) that received FK409 (300 mcg/kg/h) plus FR167653 (1 mg/kg/h) intravenously before and after the ischemic event. We evaluated animal survival, small bowel tissue blood flow, and enzyme release from the small bowel. All controls died from severe acidosis within 2 days and all the FK/FR animals survived 7 days (P < .05). The FK/FR group recovered more than 70% of blood flow immediately after the revascularization, while the flow was less than 40% among the controls. Serum creatine phosphokinase values in the control group after reperfusion were significantly higher than those in the FK/FR group. In conclusion improvement of the microcirculation by FK409 and inhibition of cytokine release by FR167653 together attenuated warm ischemic small bowel injury.

Animals↗
PubMed2004

Synergistic effect of cold and warm ischemia time on postoperative graft function and outcome in human liver transplantation.

Prolonged cold ischemia time (CIT) during graft preservation and warm ischemia time (WIT) during rewarming time have been reported to cause postoperative graft dysfunction after orthotopic liver transplantation (OLT). However, the effects of both CIT and WIT in combination on patient and graft survivals are not yet defined. The aim of this study was to determine whether simultaneously prolonged CIT and WIT were associated with early graft outcomes after clinical OLT. For analysis of liver graft survival within 90 days of OLT and postoperative graft function, 186 consecutive OLT cases were divided into four groups as follows: group A, CIT < 12 hours and WIT < 45 minutes; group B, CIT > 12 hours and WIT < 45 minutes; group C, CIT < 12 hours and WIT > 45 minutes; and group D, CIT > 12 hours and WIT > 45 minutes. The graft loss rates were 5.4% in group A, 9.8% in group B, 11.1% in group C, and 42.9% in group D. The mean highest aspartate aminotransferase (AST) value after OLT in group D (3352.3 +/- 569.4 U/L) was significantly greater than those in groups A (1411.7 +/- 169.2 U/L) and B (1931.3 +/- 362.6 U/L). The simultaneously prolonged cold and warm ischemia times significantly caused hepatic allograft injury and failure, suggesting some cumulative effects of CIT and WIT on postoperative graft function.

Adolescent↗