Biomedical subjects
Publications and source records attributed to N Sato.
Novel scalarane sesterterpenes (1-4) were isolated from a sponge, Hyrtios erecta (order Dictyoceratida). They were characterized by means of spectral analyses, X-ray crystallography, and chemical reactions. Compound 1 showed potent in vitro and in vivo antitumor activities. In addition, the structure-activity relationship was also discussed using computer-assisted structure matching of 1 and aragusterols.
Titanium plates were treated in [Ti(O2)EDTA]2- -Ca(EDTA)2- mixed solutions and/or Ca(EDTA)2- solutions (where EDTA is ethylene diamine tetra acetic acid) at pH 9-13 and 150-250 degrees C for 0.5-12 h. The film, about 50 microm thick, and consisting of mixtures of CaTiO3 and TiO2 was formed in 0.01 M [Ti(O2)EDTA]2- - 0.01 M Ca(EDTA)2- mixed solution at pH 13 and 250 degrees C for 6 h. The film consisted of large icosahedral and hexagonal particles, of about 10 microm diameter, and small aggregated particles, of about 1 microm diameter. On the other hand, the film, about 20 microm thick, consisted of hexagonal plate-like CaTiO3 particles, of about 1 microm diameter, was formed in 0.01 M Ca(EDTA)2- solution at pH 13 and 250 degrees C for 6 h. The thickness of both films increased with time, where the film formation rate in 0.01 M [Ti(O2)EDTA]2- - 0.01 M Ca(EDTA)2- mixed solution was much faster. The CaTiO3 film formed on the surface of titanium promoted the precipitation of hydroxyapatite on the substrate by the hydrothermal reactions in Ca(EDTA)2- -PO(4)3- mixed solutions.
Exocrine and endocrine functions of the pancreas were assessed in 44 Japanese patients who underwent pancreatic head resection. Functions were analyzed comparing levels before surgery, at a short-term follow-up (<2 months), and at a long-term follow-up (12-31 months). The N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-PABA) excretion test, fasting blood sugar (FBS) level, and oral glucose tolerance test (OGTT) were used to determine pancreatic function. The patients were divided into three groups according to the size of the main pancreatic duct: group 1, 15 patients with a normal sized duct (< or =3 mm); group 2, 20 with a moderately dilated duct (>3 mm, <10 mm); and group 3, 9 with a markedly dilated duct (> or =10 mm). The mean BT-PABA value (6-hr urinary PABA recovery rate) in group 1 showed no change during the postoperative period. In contrast, the BT-PABA values in groups 2 and 3 had dropped by the short-term follow-up and returned to the preoperative level by the long-term examination. FBS and 120-min OGTT levels were not different between the three groups preoperatively. Although these values showed no change in all the three groups at the short-term measurements, the FBS in group 3 and 120-min levels in all the three groups had increased at the long-term. These findings suggest that exocrine pancreatic function shows a short-term deterioration in patients with a dilated pancreatic duct but recovers to the preoperative level over the long term after pancreatic head resection. Endocrine insufficiency, however, may occur at a long-term point after surgery irrespective of the preoperative pancreatic ductal dilatation.
A 34-year-old man with refractory acute myelogenous leukemia underwent allogeneic peripheral blood stem cell transplantation (PBSCT) from his HLA-matched sibling. Engraftment was prompt and no acute GVHD developed. However, high fever persisted even after engraftment, and the patient developed headache, diplopia, vertigo and nuchal rigidity on day 20 posttransplant. Cerebrospinal fluid (CSF) showed pleocytosis with no detectable microorganisms. Despite therapy with broad-spectrum antibiotics, antifungal agents and antituberculous drugs, he developed rapid mental deterioration with seizures and died on day 40. Just prior to his death, trichomonads were isolated from both CSF and urine. Scanning electron microscopic examination identified the trichomonad as Trichomonas foetus. At autopsy, trichomonads were detected histopathologically in an area involving meningoencephalitis. To our knowledge, this is the first case of T. foetus meningoencephalitis in a recipient of allogeneic PBSCT and, more importantly, the first human case of T. foetus infection.
OBJECTIVE: Withdrawal of testosterone prevents the development of hyperglycaemia in male Otsuka-Long-Evans-Tokushima Fatty (OLETF) rats, a model of non-insulin-dependent diabetes mellitus (NIDDM), but the exact mechanism has not been established. The present studies were undertaken to examine a possible role of testosterone in the development of obesity in young OLETF rats who have not shown marked hyperphagia. METHODS: Body weight, food intake and circulating concentrations of metabolic factors including immunoreactive leptin (IRL) were measured at five weeks of age in young male OLETF rats and their lean controls, Long-Evans-Tokushima-Otsuka (LETO) rats. At six weeks of age, both LETO and OLETF rats were bilaterally orchiectomized (Orchx) and half of each group implanted with a silastic tube containing testosterone. After a three week observation period, all animals were killed and circulating concentrations of metabolic factors and the ob gene expression in retroperitoneal white adipose tissues were measured. RESULTS: Body weight and 24h food intake were already increased in OLETF rats at five weeks of age. Serum testosterone concentrations were significantly lower in OLETF rats than in LETO rats. Expression of the ob gene was significantly decreased in the retroperitoneal white adipose tissue of OLETF rats, and their serum IRL concentrations were lower. Food intake and body weight gain for three weeks after the operation were significantly lower in the Orchx group of OLETF rats than in the sham-operated group. Hyperglycaemia, accompanied by hyperinsulinaemia, was attenuated by orchiectomy in OLETF rats. Circulating IRL concentrations were significantly higher in OLETF rats than in LETO rats and decreased by orchiectomy. Testosterone supplement reversed all of the changes caused by orchiectomy in OLETF rats. In contrast, the changes, which were observed after orchiectomy in OLETF rats, were not obvious in LETO rats. CONCLUSION: The present data indicate that testosterone plays a role in the development of obesity and NIDDM in young OLETF rats, but that changes of leptin production in white adipose tissue may not be important in the development of obesity in young OLETF rats.
We established a co-culture system with a monolayer of the murine bone marrow (BM) stroma cell line, MS-5, in which human cord blood CD34+ cells differentiated to CD19+ cells. The addition of stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) highly enhanced the production of CD19+ cells. The expansion of the cell numbers was over 10(3)-fold. Furthermore, a significant proportion (<45%) of the cells expressed surface IgM (sIgM) after 5 weeks of co-culture. CD34+CD19- cells also showed a similar development of CD19+ cells and CD19+sigM+ cells. Filter separation of MS-5 cells and CD34+ cells did not inhibit the growth of CD19+ cells. However, when further purified CD34+CD19-CD13- CD33- cells were cultured in the presence of MS-5 cells with or without a separation filter, CD19+ cells did not appear in the non-contact setting. This result suggested that the highly purified CD34+CD19-CD13-CD33- progenitors require the cell-cell contact for the development of CD19+ cells, whereas other CD34+ fractions contain progenitors that do not require the contact. This co-culture system should be useful for the study of early human B-lymphopoiesis.
BACKGROUND: Although the detailed mechanism is unclear, zinc and its derivative, polaprezinc, have been reported to accelerate gastric ulcer healing in vivo. AIM: To investigate the detailed cellular mechanism of polaprezinc on gastric epithelial cells and fibroblasts with special attention to insulin-like growth factor I (IGF-I). METHODS: Isolated rabbit gastric epithelial cells formed a complete monolayer, from which a circular artificial wound with constant size was made. The restoration process was monitored by measuring wound size up to 48 h. Either polaprezinc, IGF-I, fibroblast conditioned medium or neutralized medium conditioned by anti-IGF-I antibody was added at the time of wounding. The expression of mRNA of IGF-I, hepatocyte growth factor (HGF) and transforming growth factor alpha (TGF-alpha) in fibroblasts with or without polaprezinc treatment was tested using reverse transcription polymerase chain reaction (RT-PCR). Gastric epithelial cell proliferation was also examined by bromodeoxyuridine (BrdU) staining. RESULTS: IGF-I and fibroblast conditioned medium treatment accelerated gastric epithelial restoration which included cell migration and proliferation. However, polaprezinc and neutralized conditioned medium treatment did not accelerate epithelial repair. RT-PCR for growth factor mRNA revealed the IGF-I mRNA expression in fibroblasts was increased after treatment with polaprezinc. CONCLUSION: Polaprezinc induced IGF-I production from mesenchymal cells, resulting in stimulation of epithelial cell restoration through a paracrine pathway. IGF-I may play an important role in gastric wound repair.
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Apoptosis mediated by verotoxins (VTs) has been identified in a renal carcinoma cell line, ACHN cells, which are an in vitro model of renal tubular epithelial cells. ACHN cells express the renal tubular marker CD24 as well as globotriaosyl ceramide/CD77, the receptor for VTs. VT binding to the ACHN cell surface was confirmed by positive staining with antibodies to the VTs. Treatment of ACHN cells with VTs induced prompt growth inhibition and cell death, and fragmentation of the genomic DNA in cells, typical of apoptosis, was observed. The expression of apoptotic antigen 7A6 detected by APO2.7 antibody in ACHN cells further supports the occurrence of apoptosis as a result of VT treatment. Cycloheximide enhanced VT-mediated apoptosis of ACHN cells, suggesting a strong correlation between the inhibition of protein synthesis and VT-mediated apoptosis. Moreover, tumor necrosis factor-alpha had a synergistic effect on VT-mediated apoptosis in ACHN cells. Considering the above evidence together with the clinical evidence showing the presence of apoptosis in the renal epithelium of a HUS patient, our results suggest a VT-induced apoptotic mechanism in normal renal tubular epithelium that may contribute to the pathogenesis of hemolytic uremic syndrome.
BACKGROUND: Omeprazole or lansoprazole, amoxicillin, clarithromycin (PPI/AC) therapy has been reported to provide a high cure rate of H. pylori infection with few adverse effects. Effectiveness of H. pylori therapy may vary among different geographic regions and patient populations. However, there are few reports in Japan as to its effectiveness. We have, therefore, studied the effectiveness of H. pylori therapy in a large group of Japanese patients. METHODS: For this study, 366 H. pylori-positive patients with peptic ulcer disease or non-ulcer dyspepsia (263 men and 103 women, mean age 48.5 years) were assigned to 6 groups, each receiving a different PPI/AC regimen. Group 1 received omeprazole (OPZ) 20 mg, amoxicillin (AMOX) 1500 mg, and clarithromycin (CAM) 400 mg; Group 2 OPZ 40 mg, AMOX 1500 mg, and CAM 400; and Group 3 OPZ 20 mg, AMOX 2000 mg, and CAM 600 mg daily for 14 days. The group treated with lansoprazole (LPZ) 30 mg, AMOX 1500 mg and CAM 400 mg was used for 14 days in Group 1L. OPZ 20 mg, AMOX 750 mg, and CAM 200 mg were given to Group 4 for 28 days and OPZ 20 mg, AMOX 1500 mg, CAM 400 mg was administered to Group 5 for 7 days. Cure of infection was assessed by 13C urea breath test one month after completion of therapy. RESULTS: Cure rates calculated by excluding the patients who showed borderline value of 13C urea breath test (delta 13C value between 5 and 10% in Groups 1, 1L, 2, 3, 4, and 5 were 82.7% (95% CI; 74-90), 88.9% (76-96), 84.9% (72-93), 81.3% (67-91), 84.6% (72-93), and 85.1% (72-94) on an intention-to-treat basis, and 88% (80-94), 95.2% (84-99), 95.6% (85-99), 90.7% (78-97), 95.7% (85-99) and 88.9% (76-96) on a per-protocol basis, respectively. Adverse effects that affected compliance were observed in 10 of 237 patients on 14-day regiments, one of 47 on a 28-day regimen and one of 46 on a 7-day regimen. CONCLUSION: Two weeks PPI/AC therapy is highly effective for cure of H. pylori infection in the Japanese population. The low dose one month regimen and the one week OAC regimen were also effective in our patient population.
PURPOSE: To investigate the dose-response of an aquatic microcosm exposed to gamma-rays and to test the suitability of microcosms for elucidation of the mechanisms that account for such ecological effects. MATERIALS AND METHODS: The microcosm used in this study consisted of algae Euglena gracilis Z as a producer, protozoa Tetrahymena thermophila B as a consumer and bacteria Escherichia coli DH5alpha as a decomposer. After the steady-state microcosm was irradiated with 60Co gamma-rays at various dose levels, the population densities of each species were measured. RESULTS: Irradiation at up to 100 Gy did not affect the population of the microcosm except for a temporary decrease of E. coli just after irradiation. At 500 or 1000Gy, E. coli died out just after irradiation. Only Eu. gracilis and T. thermophila could survive. Their populations, however, decreased compared with that of each control, except for a temporary increase of T. thermophila after 1000 Gy irradiation. These population changes were attributable to the extinction of E. coli in addition to the direct effects of radiation. Irradiation at 5000 Gy extinguished all species in the microcosm. CONCLUSIONS: The response of the microcosm to radiation was dose-dependent over a range of high doses. The microcosm was also shown to be suitable for examining not only direct effects but also secondary effects.
The effects of bovine serum albumin, dithiothreitol, and glycerol on PCR were studied. PCR under standard conditions failed the amplification of an enterohemorrhagic E. coli DNA fragment when the boiled bacterial cell lysate was used as the template. The addition of either one of bovine serum albumin, dithiothreitol, or glycerol in the reaction mixture allowed the specific fragment amplification; and the optimum concentrations were as follows: bovine serum albumin, 1 mg/ml; dithiothreitol, 10 mM; and glycerol, 5%. In addition, when all of the three agents were included at the above concentrations, the PCR yield was further increased. The effect of the three-agent mixture was not the template specific. Furthermore, the mixture enabled long PCR over 20 kb when Taq DNA polymerase with 3'-5' exonuclease activity was used for the amplification. Our simple PCR method allows robust PCR independent of template purity or amplification length.
The cytotoxicity of Shiga toxin (Stx) 1 and Stx2 produced by Escherichia coli to human renal cortical epithelial cells (HRCEC) in primary culture was investigated. HRCEC express CD24, the marker of renal distal tubules, as well as globotriaosyl ceramide/CD77, the receptor for Stxs. Binding of Stxs to HRCEC was confirmed by positive staining with specific antibodies to Stxs. Treatment of HRCEC with Stxs induced rapid cell death, which was reversed in the presence of neutralizing antibody specific for Stx. DNA fragmentation was found to be accompanied by Stx-mediated cell death in HRCEC, indicating that apoptosis was part of the process. These data and previous reports indicate that a variety of renal cell types, including tubular epithelial cells as well as glomerular capillary endothelial cells, may be targets for Stx-mediated apoptosis, which could contribute to the pathogenesis of hemolytic-uremic syndrome caused by Stx-producing E. coli infection.
BACKGROUND: Cisplatin is widely used in combination chemotherapy against a variety of tumors; however, the optimal administration schedule of cisplatin is still controversial. To clarify the pharmacokinetic differences according to the administration schedules of cisplatin, we compared three different administration schedules of cisplatin such as single short-term infusion, daily short-term infusion and daily continuous infusion in combination with 5-fluorouracil. Preliminary clinical responses and toxicities were also investigated. METHODS: A total of 12 courses in combination of cisplatin and 5-fluorouracil therapy was studied. The schedules of cisplatin tested were as follows: single short-term infusion (80 mg/m2, day 1,2 h div., n = 4), daily short-term infusion (20 mg/m2, days 1 to 5, 2 h div., n = 4), daily continuous infusion (100 mg/m2, 120 h, n = 4). In all schedules, 5-fluorouracil was continuously administered at a dose of 800 mg/m2/day on days 1 to 5. The area under the time-concentration curve (AUC) and the maximum concentration (Cmax) of total and free Pt were investigated. RESULTS: The highest AUC of total and free Pt and the lowest Cmax of free Pt were observed in the daily continuous infusion (total AUC; 162.53 +/- 18.39 micrograms h/ml, free AUC; 5.50 +/- 0.9 micrograms h/ml, free Cmax; 0.07 +/- 0.01 microgram/ml, mean +/- SEM). Two patients in the single short-term infusion and one patient in the daily continuous infusion indicated partial responses clinically. No nephrotoxicity or ototoxicity was observed. All toxicities were mild and tolerable in all regimens; however, the incidence of GI toxicity in daily continuous infusion seemed to be relatively higher. CONCLUSIONS: Daily continuous infusion of cisplatin gave the best pharmacokinetic results and to evaluate the clinical advantage of this schedule a prospective randomized trial should be conducted with sufficient numbers of patients.
Lysophosphatidylcholine (lysoPC), a component of oxidatively modified lipoproteins, is present in atherosclerotic lesions, and its proatherogenic properties have been demonstrated. To gain an insight into lysoPC-mediated endothelial gene expression, we applied nonradioactive differential display analysis of mRNA from lysoPC-treated and untreated human umbilical vein endothelial cells. We identified 12 up-regulated distinct genes including 5 cell growth-related genes (two phosphatases CL100 and B23/hVH-3, gravin, activating transcription factor-4, and heparin-binding epidermal growth factor-like growth factor), 3 thrombosis-related genes (plasminogen activator inhibitor-1, tissue plasminogen activator, and thrombomodulin), and 4 others (stanniocalcin, NAD-dependent methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase, BENE, and reducing agents and tunicamycin-responsive protein). We isolated a full-length cDNA of human gravin. The cDNA sequence of gravin was homologous with rat mitogenic regulatory gene or rat protein kinase C binding protein and substrate, suggesting that gravin would regulate cell growth. Thus, lysoPC apparently accelerates atherosclerosis by regulating the expression of a wide variety of genes. Our data suggest the involvement in atherogenesis of the genes hitherto regarded as atherosclerosis-unrelated.
Decreased lysosomal proteolysis in regenerating liver after 70% hepatectomy was analyzed. The activities of cathepsins B and L increased transiently 4 h after hepatectomy, began to decrease gradually reaching about 30% of the control level at 24 h, then returned to near control level after 7 days. Immunoblot and RNA blot analyses confirmed that the changes in cathepsin activities coincided with changes in protein levels and mRNA levels. In parallel with the changes in cathepsins, we found that the amounts of LGP120, LGP110, and LGP85, three integral lysosomal membrane proteins, declined significantly after hepatectomy, suggesting that the lysosomal levels are also diminished in regenerating liver. We isolated dextran-loaded lysosomes and found that the protein content and marker enzyme activities of dextran-loaded lysosomes from partially hepatectomized livers are lower by 50 and 40%, respectively, compared with control livers. This indicates that there is a significant reduction in the cellular lysosomal level in regenerating liver. In addition, we used a sensitive biochemical assay to quantify leupeptin-induced autolysosomes and found that the autophagic activity is markedly suppressed in regenerating liver as compared with normal liver. Thus, the suppression of lysosomal proteolysis in regenerating liver is attained through three steps, i. e., decreased biosynthesis of cathepsins, decreased lysosomal biogenesis, and decreased cellular autophagy.
Ribosomal proteins from a cyanobacterium Anabaena variabilis were analyzed by two-dimensional gel electrophoresis. We detected 21 protein spots of the small subunit and 29 protein spots of the large subunit. One of the spots was identified as L25 protein, which suggests that the reading frame sll1824 of Synechocystis is the L25 protein.
MS-818 is a novel synthetic pyrimidine compound that stimulates nerve regeneration and promotes synthesis of various growth factors and differentiation of astrocytes. Effects of MS-818 on gastric epithelial cells were assessed using a wound repair model with primary cultured gastric epithelial cells from rabbits. A round wound with a constant cell-free area was created and the process of restoration was monitored by measuring wound size every 12 h. Cell proliferation was monitored by sequential staining with BrdU. As previously reported, EGF (10 ng/ml) accelerated wound repair by promoting cell migration and proliferation. Although MS-818 alone had no effects, MS-818 (10-100 microM) enhanced EGF-induced acceleration of gastric epithelial restoration, including cell migration and proliferation. Although the detailed mechanism of action of this agent is still unclear, MS-818 might have favorable effects on in vivo gastric mucosal repair.