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Biomedical subjects

T Sakata

Publications and source records attributed to T Sakata.

At least 253 records · Page 14Linked to original sources
PubMed1995

The strong positive correlation between factor VII clotting activity using bovine thromboplastin and the activated factor VII level.

We compared factor VII clotting activity (FVIIc) assays using different thromboplastins to determine which is the most sensitive for activated FVII (FVIIa) or for FVII antigen (FVIIag). FVIIc levels were measured using thromboplastins derived from bovine brain (FVIIc Bov), human placenta (FVIIc Hum), and rabbit brain (FVIIc Rab). FVIIa levels were measured by fluorogenic assays using human soluble tissue factor (rsTF) or bovine rsTF. We also measured FVII activity by an amidolytic assay (FVIIc:am Hum) using human thromboplastin and a chromogenic substrate for thrombin. FVIIag levels were determined by ELISA. In the FVIIa assay, the reaction time obtained from using bovine rsTF was shorter than that with human rsTF, suggesting that the interaction of plasma FVIIa with bovine rsTF was stronger than with human rsTF. The plasma FVIIa levels measured using human rsTF and bovine rsTF were almost the same (r = 0.947, p < 0.0001). Among the three FVIIc assays, FVIIc Bov had the strongest positive correlation with the plasma FVIIa level (r = 0.886, p < 0.0001), but had no correlation with FVIIag. An increase of 1 ng/ml in the plasma FVIIa level yielded a 27.9% increase of FVIIc Bov. Plasma FVIIc Hum and FVIIc:am Hum showed moderate correlations with both FVIIa (r = 0.520, p < 0.02 and r = 0.569, p < 0.01, respectively) and FVIIag (r = 0.438, p < 0.05 and r = 0.468, p < 0.05, respectively). FVIIc Rab had the lowest correlation with FVIIa (r = 0.367, p < 0.1), but had a moderate correlation with FVIIag (r = 0.436, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Strain and sex differences in kidney carcinogenesis in rats treated with N-ethyl-N-hydroxyethylnitrosamine and uracil.

We earlier demonstrated that simultaneous administration of EHEN and uracil for 3 weeks resulted in enhancement of renal carcinogenesis in F344 female rats. Therefore, to establish a model of renal carcinogenesis in rats that can induce advanced renal carcinoma at a high incidence, differences in the susceptibility to N-ethyl-N-hydroxyethylnitrosamine (EHEN) and uracil of the kidneys in male and female rats of two strains were examined. Group 1 (male Wistar rats), group 2 (female Wistar rats), group 3 (male F344 rats), and group 4 (female F344 rats) received a 3-week simultaneous administration of 0.05% EHEN in the drinking water and 3% uracil in the diet after one week's acclimation. In all the above four groups, the rats were thereafter given a basal diet and water without chemical addition for a 29-week period. Group 5 (male Wistar rats), group 6 (female Wistar rats), group 7 (male F344 rats) and group 8 (female F344 rats) received no chemicals for the entire 33 weeks. At the end of the experiment, renal adenocarcinomas were found in 85, 68, 14 and 0% of the rats in groups 1, 2, 3 and 4, respectively. The incidence of adenomas and adenocarcinomas in Wistar rats were significantly greater than in F344 rats (p < 0.0001). These findings indicate strain and possibly sex differences in kidney carcinogenesis in rats treated with EHEN and uracil, and simultaneous administration of the two agents to male Wistar rats might have an advantage for models to induce advanced renal carcinoma at a high incidence.

Adenocarcinoma↗
PubMed1995

Protein C Osaka 10 with aberrant propeptide processing: loss of anticoagulant activity due to an amino acid substitution in the protein C precursor.

We studied the molecular basis of protein C deficiency in a family with a history of thromboembolic disease. An approximately 50% reduction in anticoagulant activity despite normal levels of protein C amidolytic activity and antigen was detected in plasma from the proband. All the exons and intron/exon junctions of the protein C gene were studied using a strategy that combined polymerase chain reaction amplification with DNA sequencing of the amplified fragments. We identified a C-to-A change at nucleotide number 1387 of the protein C gene in the proband and his mother, and this mutant was designated protein C Osaka 10. The C-to-A change resulted in the substitution of Ser for Arg at position -1, which is the processing protease cleavage site. The mutant protein C was partially purified from plasma of the patient's mother using barium adsorption followed by ion-exchange column chromatography. It eluted at the same sodium chloride concentration as normal protein C, and thus gamma-carboxylation of the mutant protein appeared to be normal. The apparent molecular weight of this mutant protein C was the same as that of the normal protein on immunoblotting. Amino-terminal sequence analysis showed that the light chain of the mutant protein C had an additional Ser at position-1. Thus, the loss of anticoagulant activity of protein C Osaka 10 can be explained by alteration of the conformation of the Gla domain by the additional Ser in the mutant molecule.

Adult↗
PubMed1995

Homeostatic maintenance regulated by hypothalamic neuronal histamine.

By manipulating hypothalamic neuronal histamine, its effects on brain functions related to homeostatic energy balance were assessed in non-obese normal and genetically obese Zucker rats. Feeding behavior was suppressed and drinking was accelerated by either activation of H1 receptors or inhibition of H3 receptors in the ventromedial hypothalamic nucleus (VMH) and the paraventricular nucleus, each of which is a satiety center. Energy deficiency in the brain, i.e., intraneuronal glucoprivation, produced satiation through histaminergic activation of VMH neurons. Such low energy intake in turn induced glycogenolysis in the astrocytes to protect energy deficit in the brain. Histamine neurons in the mesencephalic trigeminal nucleus (Me5) regulated masticatory functions, particularly eating speed, and those in the VMH controlled intake volume at meals. Hypothalamic histamine neurons were activated by high ambient temperature and also by interleukin-1beta, an endogenous pyrogen, through prostaglandin E2 to maintain homeostatic thermoregulation. Behavioral and metabolic abnormalities of obese Zuckers were the result of a defect in hypothalamic neuronal histamine. Abnormalities produced by depletion of neuronal histamine from the normal hypothalamus mimicked those of obese Zuckers. Grafting the lean fetal hypothalamus into the obese pups attenuated those abnormalities.

Animals↗
PubMed1994

Molecular analysis of T cell receptor V beta chain to detect leukemia cell clonality in patients by adaptor ligation-mediated polymerase chain reaction.

We have developed a simple and rapid method to analyze the clonality of leukemia cells. After three rounds of amplification by adaptor-ligation polymerase chain reaction (PCR), the cDNA is cut with AluI, HaeIII, RsaI, and Sau3AI, and analyzed by polyacrylamide gel electrophoresis. The size of the restriction fragments is compared to that of the published restriction fragments size each TCR-beta subfamily V region. The sensitivity of adaptor-ligation PCR restriction enzyme analysis (AL-PCR-REA) was 10(-4) MOLT-4 T-ALL cell population in the normal peripheral blood lymphocytes (PBL). Application of AL-PCR-REA to PBL and bone marrow (BM) cells from eight clinical leukemia samples indicated that a detection sensitivity was rather low, but revealed the clonality of all eight clinical samples. This AL-PCR-REA method can detect clonality without the need for either radioisotopes or sequencing procedures.

Base Sequence↗
PubMed1994

Initiation-stage enhancement by uracil of N-ethyl-N-hydroxyethylnitrosamine-induction of kidney carcinogenesis in rats.

The present study was conducted to clarify the effects of N-ethyl-N-hydroxyethylnitrosamine (EHEN) and uracil in combination on renal carcinogenesis in female F344 rats. Group 1 animals (n = 30) received a 3-week simultaneous administration of 0.05% EHEN and 3% uracil, and group 2 (n = 26) 0.05% EHEN with a lower 1.5% dose of uracil. Group 3 (n = 30) was treated with 0.05% EHEN alone and group 4 (n = 28) received only 3% uracil for 3 weeks. In all the above four groups, the rats were given basal diet and water without chemical addition for a 48-week period after the 3-week treatment period. Group 5 (n = 33) received no chemicals for the entire 52 weeks. At the end of week 52, renal adenocarcinomas were found in 53%, 31% and 13% of the rats in groups 1, 2, and 3, respectively. The present study thus demonstrated that simultaneous administration of uracil enhances the occurrence of EHEN-induced renal adenocarcinomas in rats.

Adenocarcinoma↗
PubMed1994

Establishment and characterization of nurse cell-like clones from human skin. Nurse cell-like clones can stimulate autologous mixed lymphocyte reaction.

We have established nurse cell-like clones from long-term cultures of the human skin. These human skin nurse cell (HSNC)-like clones were type I collagen+, type IV collagen-, vimentin+, cytokeratin-, CD44+, CD54+, and weakly positive for VCAM-1, and easily identified by the pseudoemperipolesis that allowed T lymphocytes to migrate beneath the HSNCs. HSNCs and various T cell lines formed a typical complex in the hanging drop culture system. The majority of human and murine T cells, and some of the tumor cell lines other than T cells, including B lymphoma and myeloblastoma cells, migrated beneath the HSNC clones. HSNC clones produced various cytokines, including IL-6, IL-7, IL-8, IL-9, granulocyte CSF (G-CSF), granulocyte-macrophage CSF (GM-CSF), macrophage CSF (CSF-1), TGF-beta 1, and c-kit ligand, but could not produce IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, TNF-alpha, or TNF-beta. These characteristics were similar to those of nurse cells established from the murine thymus. Furthermore, IFN-gamma-pretreated HSNC clones that expressed MHC class II Ags induced autologous mixed lymphocyte reaction (AMLR) in autologous PBMCs to proliferate and exhibit the cytotoxicity against altered autologous cells and various tumor cells. These results suggest that HSNCs play an important role in the immunoregulation at skin tissues.

Animals↗
PubMed1994

Short, terminally phosphorylated oligoriboguanylic acids effectively inhibit cytopathicity caused by human immunodeficiency virus.

Various synthetic ribonucleic acids were evaluated for inhibition of HIV-induced cytopathicity of cultured cells; only poly and oligoguanylic acids, but not other homopolymers, showed potent inhibitory activity. Phosphorylation of either the 5'- or 3'-end of oligoribonucleotides converted short inactive oligomers, such as dimers to effective anti-HIV agents. The efficacy of the 3'-phosphorylated phosphorothioate trimer of guanylic acid was comparable to that of other longer oligonucleotides so far reported. Phosphorothioate oligoriboguanylic acids were superior to the corresponding oligodeoxyguanylic acids in their capacity to prevent HIV cytopathicity.

Antiviral Agents↗
PubMed1994

A case report of deficiency in an inhibitor of calcium-dependent association of protein S with C4B-binding protein suggested by a modified crossed immunoelectrophoresis.

We have experienced a coagulation factor VIII-deficient patient whose plasma has normal protein S (PS) activity and masses of free PS and its bound form in complex with C4b-binding protein (C4BP). Although the patient's plasma showed a normal ratio of free PS to PS-C4BP complex in the presence of 5 mM EDTA, the plasma gave an abnormally retarding major C4BP peak together with a major PS peak in the crossed immunoelectrophoresis (CIE) in the presence of 2 mM CaCl2. It was revealed that the major peak was formed by a mixture of PS-C4BP complex and free form. The addition of normal human plasma (NHP) to the patient's plasma inhibited the retardation of the major PS-C4BP complex. These suggest that the patient's plasma lacks some component(s) to inhibit Ca(2+)-dependent association of PS with C4BP.

Adult↗
PubMed1994

Hypothalamic neuronal histamine regulates feeding circadian rhythm in rats.

To clarify involvement of hypothalamic neuronal histamine in feeding circadian rhythm, we analyzed rat behavioral patterns using chemical probes which affect endogenous histaminergic activity. Sustained infusion of alpha-fluoromethylhistidine (FMH), a specific suicide inhibitor of a histamine-synthesizing enzyme, into the rat third cerebral ventricle disrupted light-dark cycles of feeding, drinking, and ambulatory behavior. Food and water intake and ambulatory activity during the 12-h light period increased, and those during the 12-h dark period decreased after the infusion. The ratio of the light period to the 24-h total period (L/T ratio) increased in all behavioral parameters. Assessed by 3-h cumulative analysis, amplitudes of circadian rhythmicity decreased in all behavioral parameters, whereas only the acrophase of ambulatory activity shifted forward after FMH infusion. Chlorpheniramine, an H1-antagonist, selectively increased food intake during the light and decreased it during the dark period. Consequently, the antagonist increased the L/T ratio in food intake, but did not affect the ratio in water intake or ambulatory activity. Famotidine, an H2-antagonist, did not affect the ratio in any parameter. Thioperamide, an antagonist of auto-inhibitory effects on histamine synthesis and release at presynaptic H3-receptor sites, decreased food intake during the dark, but did not affect the L/T ratio in any parameter. These findings indicate that neuronal histamine may regulate feeding circadian rhythm through the hypothalamic histamine H1-receptor in rats.

Animals↗
PubMed1994

Analysis of the population of human T cell receptor gamma and delta chain variable region subfamilies by reverse dot blot hybridization.

We have developed a simple method to analyze the population of T cell receptor (TCR) gamma and delta chain variable (V) region subfamilies by the application of reverse dot blot hybridization, which was originally developed for the analysis of human HLA-DR polymorphism. The four oligonucleotides corresponding to each TCR-gamma V region subfamily and the six oligonucleotides to each TCR-delta V region gene were synthesized, and tailed with dTTP. The cDNA was amplified by ligation-mediated PCR in the presence of biotinylated deoxynucleotides. Hybridization between immobilized specific oligoprobes and biotinylated target DNA was nonradioactively detected by a reaction using alkaline phosphatase. The population of the V region subfamilies of TCR-gamma and -delta in PBL analyzed by reverse dot blot hybridization described here showed good correlations with the result of colony hybridization.

Base Sequence↗
PubMed1994

Stimulation of in vitro hematopoiesis by a murine fetal hepatocyte clone through cell-cell contact.

We have previously shown that a fetal liver-derived epithelial cell clone, FHC-4D2, could support hematopoiesis in vitro through its colony-stimulating factor (CSF) activities in a short-term culture. In this study, since FHC-4D2 cells were found capable of maintaining hematopoietic progenitors in the coculture for a long time, we examined how FHC-4D2 could exert hematopoietic supporting activity in a long-term culture by coculturing adult bone marrow (BM) cells or fetal liver (FL) cells on a monolayer of FHC-4D2 cells. This clone could maintain the colony-forming unit of granulocytes and macrophages (CFU-GM) of BM for > or = 12 weeks under the coculture condition, but the fibroblastic cell clone from the fetal liver, FHC-4A3, could not support the survival of CFU-GM, even for 1 week. In addition to BM CFU-GM, the FHC-4D2 clone also supported the survival of FL CFU-GM, burst-forming unit of erythroid cells (BFUe), and colony-forming unit of mixed progenitors (CFU-Mix) for longer than 4 weeks. When BM cells were separated by a membrane filter from the FHC-4D2 cells in the coculture, the comparable number of CFU-GM was maintained at day 3, but virtually no hematopoietic progenitors were detected at the end of the first week. CFU-GM were present in both nonadherent and adherent cells to the FHC-4D2 cells at day 3 of the coculture, but at day 7, the adherent population contained greater number of CFU-GM. CFU-GM derived from the adherent cells formed larger colonies and contained more bipotential CFU-GM than the nonadherent population. When BM cells from mice given 5-fluorouracil were cocultured with FHC-4D2 cells under the limiting dilution condition, interleukin-3 (IL-3)-responsive CFU-GM were induced from immature hematopoietic progenitor cells that were otherwise unresponsive to IL-3. From these data we conclude that the FHC-4D2 clone could generate and maintain IL-3-responsive hematopoietic progenitors via close contact and that, in the fetal liver, the contact between hepatocytes and hematopoietic cells may be critically important in inducing the differentiation of resting, IL-3-unresponsive immature hematopoietic cells into CFU-GM (progenitors responsive to IL-3) and in triggering the self-renewal of CFU-GM.

Animals↗
PubMed1994

Elevated concentrations of the beta-subunit of S100 protein in renal cell tumors in rats.

Concentrations of alpha and beta-subunits of S100 protein (S100-alpha and S100-beta) in rat kidney neoplasms, including renal cell and mesenchymal tumors, were determined using a highly sensitive enzyme immunoassay, and both types immunohistochemically localized in tissue sections. Concentrations of S100-alpha in each histological type of rat tumor were lower than in normal kidney, whereas levels of S100-beta (mean +/- SE: 29.7 +/- 14.2 ng/mg protein, n = 15) in renal cell tumors were significantly higher than in normal kidneys (0.55 +/- 0.06 ng/mg protein, n = 7), or mesenchymal tumors (1.21 +/- 0.43 ng/mg protein, n = 9). In normal rat kidney tissues S100-alpha was immunohistochemically positive in epithelial cells of the distal tubules, the thin limbs of loops of Henle, and the collecting ducts. No appreciable immunostaining for S100-beta was found in any nephron segment. Both S100-alpha and S100-beta were positive for renal cell tumors, indicating new appearance of the latter during renal carcinogenesis in rats.

Animals↗
PubMed1994

A randomized trial of early intravesical instillation of epirubicin in superficial bladder cancer. The Nagoya University Urological Oncology Group.

A total of 135 patients with superficial bladder cancer diagnosed as totally resectable were entered into a randomized multicenter trial to investigate the efficacy of early intravesical epirubicin instillation after resection in comparison with transurethral resection (TUR) alone. Epirubicin (40 mg/40 ml saline) was given within 24 h of TUR and once during the 1st week, weekly for 4 weeks and then monthly for 11 months. In all, 122 patients (90.4%) were eligible and 119 (88.1%) were evaluable. The interval to initial recurrence was significantly longer (P = 0.02) in the epirubicin group (36 months; 95% confidence interval, 32-40 months) than in the group receiving TUR alone (28 months; 95% confidence interval, 24-32 months). The recurrence rate per year in the epirubicin group was less than that in the TUR-alone group (0.13 versus 0.29 annual recurrences). Disease progression was observed in only one patient in the epirubicin-instillation group. The main toxicity encountered was bladder irritation (13.8%). These results demonstrate that early intravesical epirubicin instillation is efficacious in preventing local recurrence.

Administration, Intravesical↗
PubMed1994

Clinicopathological characteristics of small renal cell carcinomas.

To clarify the clinicopathological characteristics of small renal cell carcinomas (RCCs) the authors reviewed data for 154 RCC patients treated between January 1980 and September 1992. Of 20 patients with tumours of 3 cm or less in diameter, 12 (60%) had no related symptoms: 6 (30%) were found during routine physical check-ups and 6 (30%) were incidentally detected during examinations for diseases other than RCC. The remaining 8 (40%) patients demonstrated indicative symptoms. Most small tumours showed expansive growth and nuclear atypia was minimal or moderate. In all 20 cases, the lesions of 3 cm or less were confined to the kidney (pT1 to pT2b) and no lymph node metastasis was found. Only one (5%) had a distant metastasis, and venous involvement was also microscopically observed in only one patient (5%). The 5-year survival rates were 95% for patients with tumours of 3 cm or smaller, 74% for those of 3.1 to 5 cm, and 68% for those of greater than 5 cm. These findings revealed small RCC to demonstrate biologically less malignant behaviour. Early detection of such small lesions by ultrasonography should therefore improve the overall survival of patients with RCC.

Adult↗
PubMed1994

Total cystectomy after intravesical bacillus Calmette-Guérin (Tokyo strain) therapy for superficial bladder cancer: experience in Japan.

To clarify which patients might most require total cystectomy after intravesical bacillus Calmette-Guérin (BCG) therapy, we reviewed data for 111 individuals with superficial bladder cancer. Of the 111 patients, 73 received the BCG treatment for prophylaxis of intravesical recurrence after transurethral resection (group 1), 24 therapeutically for Ta or T1 tumours (group 2), and 14 for eradicating carcinomas in situ (CIS, group 3). Although the BCG therapy significantly reduced frequencies of recurrence in group 1, 27 patients (37%) did develop tumours again. Tumours disappeared in 18 of 24 patients (75%) in group 2, and in 11 of 14 (79%) in group 3. The rate of disease progression was 6% for all 111 patients: 3% (2/73) for group 1, 17% (4/24) for group 2, and 7% (1/14) for group 3. A total of 16 of the 111 patients (14%) underwent total cystectomy, the respective figures being 7% in group 1, 29% in group 2, and 29% in group 3. Indications for total cystectomy were progression in 7, recurrent multiple tumours in 5, persistent CIS in 2, a contracted bladder in 1, and occurrence of bilateral renal pelvic cancer in 1. Thus, 4 of 6 patients (67%) who had tumours unresponsive to BCG therapy in group 2 demonstrated progression and necessitated total cystectomy. Because tumours persisting after BCG therapy are frequently of the muscle-invasive type, such cases should be regarded as candidates for immediate total cystectomy.

Administration, Intravesical↗