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Biomedical subjects

M Kato

Publications and source records attributed to M Kato.

At least 235 records · Page 13Linked to original sources
PubMed2001

Antidiabetic activity of the rhizoma of Anemarrhena asphodeloides and active components, mangiferin and its glucoside.

The antidiabetic activity of the rhizoma of Anemarrhena asphodeloides was investigated in KK-Ay mice, an animal model of genetic type 2 diabetes. The water extract of the rhizoma (AA) (90 mg/kg) reduced blood glucose levels from 570 +/- 29 to 401 +/- 59 mg/dl 7 h after oral administration (p<0.05) and also tended to reduce serum insulin levels in KK-Ay mice. AA-treated KK-Ay mice had significantly reduced blood glucose levels in an insulin tolerance test. Based on these results, the antidiabetic mechanism of AA may be due to decreased insulin resistance. In addition, the active components of AA were confirmed to be mangiferin and its glucoside.

Animals↗
PubMed2001

The suppressive effect of mangiferin with exercise on blood lipids in type 2 diabetes.

The effect of mangiferin (MF) with exercise on bood lipids was studied in KK-Ay mice, an animal model of type 2 diabetes. MF (30 mg/kg) reduced the blood cholesterol (p<0.05) and triglyceride level (p<0.01) of KK-Ay mice with exercise 2 weeks after oral administration when compared with the control group. Diabetes also often has elevated lipid levels. Therefore, it may be that MF has beneficial effects on hyperlipidemia in type 2 diabetes.

Animals↗
PubMed2001

Short-term physical training improves ventilatory response to exercise after coronary arterial bypass surgery.

The issue of whether exercise training improves exercise hyperpnea in patients after coronary arterial bypass graft (CABG) surgery has not been fully explored. Effects of short-term physical training on ventilatory response and cardiac output during exercise in patients following coronary arterial bypass grafting surgery is studied. Thirty-four patients underwent exercise training for 2 weeks after the second postoperative week (Ex group); 23 stayed sedentary (Sed group). Ventilatory and cardiac output response during the cardiopulmonary exercise test was measured before and after the training period. The minute ventilation-carbon dioxide output (VE-VCO2) slope decreased from 38.9+/-8.1 to 35.1+/-6.7 (p<0.05) in the Ex group, but failed to decrease in the Sed group (39.7+/-11.1 to 41.5+/-11.4). Cardiac output during exercise at 20W and at peak exercise, and peak oxygen pulse (VO2/HR) increased significantly only in the Ex group after training. There was a correlation between improvement of the VE-VCO2 slope and peak cardiac output during the training interval (r=-0.47) in the Ex group. Short-term physical training after CABG improves ventilatory response to exercise and increases cardiac output during exercise. Improvement of cardiac output is correlated with a decreased value of the VE-VCO2 slope.

Aged↗
PubMed2001

In vivo and in vitro analyses of the AmyR binding site of the Aspergillus nidulans agdA promoter; requirement of the CGG direct repeat for induction and high affinity binding of AmyR.

The alpha-glucosidase gene (agdA) of Aspergillus nidulans has a single CGGN8CGG type AmyR binding site in its promoter region. The binding site is functional in vivo as a cis-element responsible for induction by starch, and mutational studies indicated that both the CGG triplets are required for high-level induction. A part of AmyR (residues 1-411; AmyR(1-411)), which was produced as a MalE fusion protein in E. coli, bound to the CGGN8CGG site of the agdA promoter. DNA binding profiles to the mutant binding sites that lacked both or either one of the CGG triplets suggested that AmyR(1-411) can bind to a single CGG triplet site with low affinity and that two AmyR molecules cooperatively bind to the CGG direct repeat.

Aspergillus nidulans↗
PubMed2001

No factors except for the hap complex increase the Taka-amylase A gene expression by binding to the CCAAT sequence in the promoter region.

To examine the possibility that factors different from the Hap complex are involved in increasing Taka-amylase A gene (taa) expression in Aspergillus nidulans, either the authentic taa gene or the mutant taa gene with a replacement of the CCAAT box was expressed in either a wild type strain or a mutant strain lacking the functional Hap complex (hapCdelta). When the mutant taa was expressed in the hapCdelta strain, enzyme activity was as low as that of the hapCdelta strain transformed with the authentic taa gene, indicating that no factors except for the Hap complex increase transcription of the taa gene by binding to the CCAAT sequence.

Aspergillus nidulans↗
PubMed2001

A case of renovascular hypertension due to bilateral renal artery microaneurysm who succeeded in baby delivery.

We report the case of a young pregnant woman with bilateral renovascular hypertension due to renal microaneurysms from an unknown cause, who had a successful delivery. Pregnancy did not affect the disease activity even in the postpartum period. Her blood pressure was maintained within the normal range by administration of labetalol. Although the angiographic appearance of the symmetrical aneurysms in both renal artery beds from the interlobular to arcuate artery levels suggested polyarteritis nodosa of multiple microaneurysms in the bilateral interlobular arteries, the clinical features suggested other causes of renovascular hypertension, such as fibromuscular dysplasia and/or congenital microaneurysms. We were thus unable to reach a definitive diagnosis.

Adrenergic beta-Antagonists↗
PubMed2001

Focal adhesion kinase activity is required for bone morphogenetic protein--Smad1 signaling and osteoblastic differentiation in murine MC3T3-E1 cells.

Cell-matrix interactions via integrins are essential for osteoblastic differentiation. We have shown that signals activated by aggregation of alpha2beta1-integrin with type I collagen are involved in the differentiation of osteoblastic MC3T3-E1 cells. Focal adhesion kinase (FAK) is an immediate downstream signal of the beta1-integrin, and inactivation of FAK has been shown to disrupt osteoblastic differentiation. To elucidate roles of FAK in osteoblastic cells, we examined MC3T3-E1 cells stably expressing antisense FAK (asFAK) messenger RNA (mRNA). Alkaline phosphatase (ALP) activity, an osteoblastic marker, did not increase in asFAK cells with a long-term culture until 21 days or in response to bone morphogenetic protein 2 (BMP-2). Treatment with BMP-2 also failed to stimulate the expression of osteocalcin in asFAK cells. In control MC3T3-E1 cells, BMP-2 induced translocation of Smad1 into nuclei to stimulate transcriptional activity of the Smad6 promoter gene that contains a Smad1 response element. In contrast, BMP-2 failed to increase transcriptional activity of Smad6 promoter gene in asFAK cells, although it induced nuclear translocation of Smad1. These results indicate that FAK was involved in Smad1-dependent transcriptional activity but not in nuclear translocation of Smad1 in osteoblastic cells. Hence, FAK activation by integrins might converge transcriptional activation by BMP of its target genes in osteoblastic cells. These observations suggest that FAK activity is essential for BMP-Smad signaling to stimulate osteoblastic differentiation.

Actin Cytoskeleton↗
PubMed2001

The immunohistochemical expression of stress-response protein (srp) 60 in human brain tumours: relationship of srp 60 to the other five srps, proliferating cell nuclear antigen and p53 protein.

This study analyzed the expression of stress-response (heat-shock) protein 60 (srp 60) in a series of 158 human brain tumours. Immunohistochemical procedures were employed; cells of the human cervical cancer line HeLa S3 exposed to hyperosmolar stress served as positive controls. Deposits of reaction products were found in the cytoplasm. Approximately half of the glioblastomas multiforme (17/31), breast carcinoma metastases (6/10), and lung carcinoma metastases (5/11) as well as about one-third of the astrocytomas (5/13) and meningiomas (8/23) had tumour cells that expressed srp 60. A positive reaction for srp 60 was also seen in some medulloblastomas (2/16), primitive neuroectodermal tumours (PNETs) (2/11), schwannomas (2/21), and pituitary adenomas (2/7), but no positive reactions were observed with oligodendrogliomas and ependymomas. Compared with srp 60-negative tumours, srp 60-positive tumours coexpressed one or more stress-related proteins, among which srp 90, srp 72, srp 27, alphaB-crystallin and ubiquitin occurred with higher frequencies; a high correlation between srp 60 and the other five srps (0.88 - 0.97, p<0.01, Pearson correlation coefficient) was observed in srp 60-positive tumours. In contrast, the correlation coefficient in srp 60-negative tumours was not significant (-0.26 - 0.71). There was a tendency for the proliferating cell nuclear antigen (PCNA)-labeling index to be higher in glioblastomas, astrocytomas, medulloblastomas, PNETs, and breast and lung carcinoma metastases that expressed srp 60 than in those that did not. No significant immunohistochemical reactions of srp 60, PCNA and p53 protein were seen with sections of normal brain tissues. We conclude that primary and metastatic tumours of the brain produce srp 60 and that srp 60 in certain brain tumour cells may coexpress the other five srps. In addition, srp 60 expression might depend, in part, on proliferating potential.

Adolescent↗
PubMed2001

Overview of studies on rat sperm motion analysis using a Hamilton-Thorne Sperm Analyzer--collaborative working study.

This collaborative study was conducted to determine the utility and sensitivity of nine sperm motion parameters generated by a Hamilton-Thorne Sperm Analyzer (HTM-IVOS) for detecting adverse effects of chemicals on sperm motion in rats. The efficacy of sperm motion parameters was investigated using nine reproductive toxicants: adriamycin, alpha-chlorohydrin (3 different studies were carried out), dinoseb, ethylene glycol monoethyl ether, 2,5-hexanedione, sulfasalazine, trimethyl phosphate, and ornidazole. The percentage of motile sperm (% motile sperm), the only parameter expressing the status of semen containing non-motile sperm, detected adverse effects on sperm motion in 9 out of 10 studies. However, weak effects on sperm motion were not detected by this parameter in 4 out of 7 studies in which sperm motion disorders were noted at medium or low dosages. The percentage of progressively motile sperm (% progressive sperm) and the sperm velocity parameters (average path velocity, straight line velocity, and curvilinear velocity) detected adverse effects on sperm motion in all studies. In 7 studies which noted sperm motion disorders at medium or low dosages, weak effects on sperm motion were detected by the % progressive sperm in 5 studies and by the sperm velocity parameters in 6 studies. In 10 studies, amplitude of lateral head displacement (ALH) did not detect adverse effects on sperm motion in 4 studies, and beat cross frequency (BCF) failed to detect adverse effects on sperm motion in 3 studies. Because ALH and BCF show the swimming pattern of spermatozoa as head movement, the characteristics of these parameters are different from the % progressive sperm and the sperm velocity parameters. Straightness (STR) and linearity (LIN), which are secondary parameters calculated from sperm velocity parameters, could not detect adverse effects on sperm motion when the sperm velocity parameters did not detect adverse effects. On the basis of these results, we concluded that the % progressive sperm and sperm velocity parameters are useful and sensitive indicators for detecting adverse effects on sperm motion. However, in the % progressive sperm, setting up a suitable threshold of VAP and/or STR is important to gain further sensitivity for detecting adverse effects on sperm motion. The % motile sperm is useful for assessment of sperm motion disorder, and ALH and BCF are useful for evaluating the swimming pattern of sperm. STR and LIN are not very useful for detecting adverse effects on sperm motion.

Animals↗
PubMed2001

Sperm motion analysis in rats treated with adriamycin and its applicability to male reproductive toxicity studies.

Adriamycin (ADR), an anticancer drug which induces testicular toxicity, was administrated to Slc:SD male rats at doses of 0.5, 1.0, and 2.0 mg/kg intravenously once a week for 4 weeks. The males treated with ADR were mated with untreated females, and sperm analyses (motion, count, and morphology) were performed. Sperm motion was analyzed by Hamilton-Thorne Sperm analyzer (HTM-IVOS) to investigate the useful parameters. Copulated females were necropsied at Day 13 of gestation, and reproductive status was evaluated. In ADR-treated groups, the testicular weight was dose-dependently decreased. Associated with this decrease was a depletion of the number of spermatogonia noted histopathologically at all dosage levels. Sperm morphological abnormalities, which were classified as tailless sperm and/or no-hook head sperm, were increased in both the 1.0 and 2.0 mg/kg groups. The males treated with ADR at 1.0 and 2.0 mg/kg had a decreased number of sperms per cauda epididymis. In sperm motion analysis, decreases in the percentage of motile sperm, percentage of progressive sperm, and sperm velocity (straight line velocity and curvilinear velocity) were noted at 2.0 mg/kg. Impaired fertility was noted at 2.0 mg/kg in the form of decreased numbers of implantations and live embryos, and an increased number of pre-implantation losses. In conclusion, ADR induced deterioration of sperm motion and sperm content, which were responsible for the adverse effect on male fertility. The most sensitive indicators to detect male reproductive toxicity induced by ADR were testicular weight and histopathological findings in the testis. Among the parameters generated by HTM-IVOS, the percentage of motile sperm, the percentage of progressive sperm, and sperm velocity are useful for assessing male fertility.

Animals↗
PubMed2001

Hypoglycemic activity of the fruit of the Momordica charantia in type 2 diabetic mice.

The antidiabetic activity of Momordica charantia L. (Cucurbitaceae) was investigated in KK-Ay mice, an animal model with type 2 diabetes with hyperinsulinemia. The water extract of the fruit of Momordica charantia L. (MC) reduced the blood glucose of KK-Ay mice 3 weeks after oral administration (p<0.01) and also significantly lowered the serum insulin of KK-Ay mice under similar conditions (p<0.01). However, MC did not affect the blood glucose in normal mice. MC-treated KK-Ay mice blood glucose significantly decreased in an insulin tolerance test. Moreover, the muscle content of facilitative glucose transporter isoform 4 (GLUT4) protein content in the plasma membrane fraction from muscle significantly increased in the orally MC-treated mice when compared with that of the controls (p<0.01). These results suggest that the antidiabetic effect of MC is derived, at least in part, from a decrease in insulin resistance because of the increase of GLUT4 protein content in the plasma membrane of the muscle.

Administration, Oral↗
PubMed2001

Dimethyl sulfoxide inhibits dimethylnitrosamine-induced hepatic fibrosis in rats.

We studied the preventive effects of dimethyl sulfoxide (DMSO) on experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. Treatment with DMN caused a significant decrease in body and liver weight. Oral DMSO (2 ml/kg daily for 4 weeks) essentially prevented this DMN-induced body and liver weight loss with no major side effects. DMSO suppressed the induction of hepatic fibrosis, as determined by histological evaluation, and reduced hepatic hydroxyproline. It also suppressed the expression of mRNA for type I collagen in the liver. Because hepatic stellate cells (HSC) are the major cellular source of the collagen in hepatic fibrosis, we examined the effects of DMSO on collagen production in vitro using rat primary HSC culture. However, it was found that DMSO did not inhibit the collagen production in vitro. We next evaluated the effects of DMSO on tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO) production by Kupffer cells, because these factors represent major activator of HSC, and because monocyte-macrophage infiltration has been implicated as being pathogenetically important for hepatic fibrosis induced by DMN. DMSO inhibited lipopolysaccharide (LPS)-induced TNFalpha and NO production, and reduced TNFalpha mRNA levels. DMSO also suppressed the LPS-induced nuclear factor kappa B activation in a murine macrophage-like cell line. These results suggest that the inhibitory effects of DMSO on hepatic fibrosis may be primarily exerted via blocking of DMN-induced inflammation. These results also implied that DMSO may be potentially useful for preventing the development of hepatic fibrosis.

Animals↗
PubMed2001

[The significance of early detection for prostate cancer in mass screening].

PURPOSE: In Mitaka city, mass screening for prostate cancer was conducted for 3 years from 1995 to 1997. Clinical stages were compared between patients found by screening and those diagnosed at our clinic during the same time. The significance of serum-free prostate specific antigen (PSA) in mass screening for prostate cancer was examined. MATERIAL AND METHODS: A prospective clinical trial was conducted on men aged 50 years or older. The primary examination consisted of taking the international prostate symptom score, quality of life score, PSA (Tandem-R) and digital rectal examination (DRE). If PSA was greater than 4.0 ng./ml and/or if DRE suggested cancer, transrectal ultrasound-guided sextant prostate biopsies were indicated. RESULTS: Of the men screened, 23.2% (320/1375) had serum PSA greater than 4.0 ng./ml. and/or suspicious findings on DRE. Biopsy was performed in 199 of 320 (62.1%). Cancer was detected in 21 (1.5%, 21/1375). Prostate cancer was found in one case among 154 males (0.65%, 1/154) who were screened twice or more. The cancer stage found by screening was significantly earlier than that diagnosed at the outpatient clinic (Wilcoxon's rank-sum test: p = 0.0047). Receiver operating characteristics analysis showed that the optimal free PSA-to-PSA ratio was 12%. Positive predictive value increased from 18% to 50% when free PSA-to-PSA ratio was combined with PSA. CONCLUSION: 1. Cancer detection rate was 1.5% in the mass screening in Mitaka City. 2. Cancer stage found by screening was significantly earlier than that diagnosed at the outpatient clinic. 3. Free PSA determination might eliminate unnecessary biopsies in men with PSA above 4.0 ng./ml with minimal loss of cancer detection.

Aged↗
PubMed2001

[Comparisons of factors affecting voiding disorders between patients with benign prostate hyperplasia and volunteers].

PURPOSE: The prostate size and motivation to visit clinics were investigated in patients with prostate hyperplasia. OBJECTS AND METHODS: One hundred ninety-five patients who had urinary symptoms and visited our outpatient clinic between September 1994 and October 1999 and 268 age-matched volunteers in Mitaka City who underwent a medical examination of the prostate in June 1997 were compared. International Prostate Symptom Score (IPSS), Quality Of Life Score (QOL score), residual urine volume, prostate volume and urinary flow rate were measured. RESULTS: The prostate volume of the volunteers was 20-25 cm3 irrespective of the age. The prostate size of the outpatients was larger than that of the volunteers for every age group. IPSS and QOL score were significantly higher in the outpatients than in the volunteers. Diurnal urinary frequency and sense of residual urine contributed to the discrimination index of the two groups more significantly than the other scores. There was a significant correlation between prostate volume and residual urine volume. The score of weak urinary steam was inversely and significantly correlated with peak urinary flow rate. CONCLUSIONS: There was no age-related enlargement of the prostate gland. The prostate gland was significantly larger in the patients than in the volunteers even in those in their fifties. Urinary frequency and sense of residual urine are important factors for men to seek and receive medical care.

Adult↗
PubMed2001

Heparan sulfate and chondroitin sulfate proteoglycans inhibit E-selectin binding to endothelial cells.

E-selectin is a cell adhesion molecule involved in the initial rolling and adhesion of leukocytes to the endothelium during inflammation. In addition, in vitro studies have suggested that an interaction between E-selectin and binding sites such as sialyl Lewis X-containing oligosaccharides on endothelial cells may be important for angiogenesis. In order to investigate the binding of E-selectin to endothelial cells, we developed an ELISA assay using chimeric E-selectin-Ig molecules and endothelial cells fixed on poly-L-lysine coated plates. Our results indicate that E-selectin-Ig binds to both bovine capillary endothelial cells and human dermal microvascular endothelial cells in a calcium-dependent and saturable manner. The binding is inhibited markedly by heparin and by syndecan-1 ectodomain, and moderately by chondroitin sulfate, but not by sialyl Lewis X-containing oligosaccharides. These results suggest that heparan sulfate and chondroitin sulfate proteoglycans on endothelial cells are potential ligands for E-selectin.

Animals↗
PubMed2001

[A case of hyperperfusion syndrome treated successfully by propofol].

Carotid endoarterectomy was performed for a 67-year-old male with severe stenosis in the right carotid artery under propofol-fentanyl anesthesia. After the surgery, blood pressure was controlled by sodium nitroprusside to maintain at the preoperative level. On the first postoperative day, he was alert and without neurological deficit, but he became restless with the left hemiparesis appearing on the next day. ECD-SPECT revealed hyperperfusion of the right hemisphere. Propofol was administered at the dose of 3-5 mg.kg-1.h-1 to normalize the perfusion. It appears that the cerebral blood flow was normalized. Hyperperfusion after carotid endoarterectomy can be controlled by propofol.

Aged↗
PubMed2001

[Recent guidelines for the management of Helicobacter pylori infection].

The guidelines for the diagnosis and treatment of H. pylori infection have been developed in Europe, United States, Asia, and Japan. Each guideline is characteristic in recommended indication, diagnostic method, and eradication regimen, because it depends on different background of medical situation. Two guidelines were reported in 2000. One is Maastricht 2-2000 consensus report, another is the guideline of Japanese Society for Helicobacter Research. In this article, European and Japanese recent statement for the management of H. pylori infection were introduced to reveal the differences in indication, diagnosis, and treatment between both guidelines.

2-Pyridinylmethylsulfinylbenzimidazoles↗