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Biomedical subjects

M Usami

Publications and source records attributed to M Usami.

At least 19 recordsLinked to original sources
PubMed2004

Insulin secretion and insulin sensitivity at different stages of glucose tolerance: a cross-sectional study of Japanese type 2 diabetes.

To evaluate the factors causing glucose intolerance in type 2 diabetes in Japan, insulin secretion and insulin sensitivity were compared across the range of glucose tolerance. Subjects were divided into 3 groups: normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and type 2 diabetes (DM) according to the criteria of the World Health Organization (WHO). We examined insulin secretion and insulin sensitivity using fasting blood glucose and insulin levels and 75 g oral glucose tolerance test (OGTT). We used homeostasis model assessment (HOMA) beta-cell and insulinogenic index (30 minutes) to estimate insulin secretion and HOMA-insulin resistance (IR) and insulin sensitivity index (ISI) composite for insulin sensitivity. Although insulin resistance plays an important role in the development of diabetes in many ethnic populations, the differences in insulin sensitivity between NGT and IGT and between IGT and DM are small in Japanese patients. On the other hand, as glucose intolerance increases, insulin secretion decreases most remarkably both between NGT and IGT and between IGT and DM in Japanese patients. Decreasing insulin secretion and decreasing insulin sensitivity both occur in developing type 2 diabetes in Japanese patients, but decreased basal and early-phase insulin secretion had more pronounced contribution to glucose tolerance than the indices of insulin sensitivity. Japanese type 2 diabetic patients are characterized by a larger decrease in insulin secretion and show less attribution of insulin resistance.

Aging↗
PubMed2003

A prospective and randomized study of primary hormonal therapy for patients with localized or locally advanced prostate cancer unsuitable for radical prostatectomy: results of the 5-year follow-up.

OBJECTIVE: To evaluate the effect of primary hormonal therapy for patients with localized and locally advanced prostate cancer. PATIENTS AND METHODS: Patients with stage T1b-T3 prostate cancer who were not scheduled for radical prostatectomy were allocated into two groups: group 1 (73 men) received luteinizing hormone-releasing hormone (LHRH) agonist monotherapy and group 2 (78 men) received LHRH agonist and chlormadinone acetate. Patients were followed using serum prostate specific antigen levels, prostate size and the detection of distant metastasis for 5 years. RESULTS: The median (range) follow-up was 78 (63-87) months. The 5-year progression-free survival rate was significantly higher in group 2 (68%) than in group 1 (47%). However, the overall and cause-specific survival rate at 5 years were similar in both groups, at 72% and 93% in group 1, and 64% and 89% in group 2, respectively. CONCLUSION: The overall survival rates of the both groups were no different from that of the normal Japanese population of the same age group. Although this study did not include an untreated group, i.e. watchful waiting, these results might indicate the usefulness of primary hormonal therapy in controlling localized and locally advanced prostate cancer. The 5-year observation period is still short and the study is continuing to determine the 10-year survival.

Aged↗
PubMed2002

Development of a THz spectroscopic imaging system.

We have developed a real-time THz imaging system based on the two-dimensional (2D) electro-optic (EO) sampling technique. Employing the 2D EO-sampling technique, we can obtain THz images using a CCD camera at a video rate of up to 30 frames per second. A spatial resolution of 1.4 mm was achieved. This resolution was reasonably close to the theoretical limit determined by diffraction. We observed not only static objects but also moving ones. To acquire spectroscopic information, time-domain images were collected. By processing these images on a computer, we can obtain spectroscopic images. Spectroscopy for silicon wafers was demonstrated.

Diagnostic Imaging↗
PubMed2001

Human wild presenilin-1 mimics the effect of the mutant presenilin-1 on the processing of Alzheimer's amyloid precursor protein in PC12D cells.

Most familial early-onset Alzheimer's disease (FAD) is caused by mutations in the presenilin-1 (PS1) gene. Abeta 42 is derived from amyloid precursor protein (APP) and increased concentrations are widely believed to be a pathological hallmark of abnormal PS function. Thus, the interaction between PS1 and APP is central to the molecular mechanism of AD. To examine the effect of wild-type human PS1 on rat APP metabolism, we made several PC12D cell lines that expressed human wild or mutant PS1, and analyzed the processing of endogenous rat APP and the intracellular gamma-secretase activity. We found the ratio of Abeta 42/Abeta 40 increased in PC12D cells expressing wild-type human PS1. These changes were identical to those found in PC12D cells expressing human PS1 bearing the A260V mutation. These results suggest that APP metabolism is physiologically regulated by the PS1 and that loss of normal PS1 affects gamma-secretase activity.

Alzheimer Disease↗
PubMed2001

Effect of eicosapentaenoic acid (EPA) on tight junction permeability in intestinal monolayer cells.

UNLABELLED: The purpose of this study is to evaluate the effect of C18 and C20 long chain fatty acids on tight junction permeability in a model of intestinal epithelium. METHODS: Confluent Caco-2 cells on porous filters with double chamber system were used to measure fluorescein sulfonic acid (FS) permeability and transepithelial electrical resistance (TEER). Lactate dehydrogenase release and ultrastructure were evaluated. Effect of 200 microM eicosapentaenoic acid (EPA, C20:5 n-3), arachidonic acid (AA, C20: 4 n-6), alpha-linoleic acid (ALA, C18: 3 n-3), linoleic acid (LA, C18: 2 n-6), or oleic acid (OA, C18: 1 n-9) enrichment in the culture medium during 24 hours were compared. The effect of the cyclooxygenase inhibitor, indomethacin, lipoxygenase inhibitors, NDGA or AA861, and antioxidant, BHT, was evaluated as a mechanism to change tight junction permeability. RESULTS: Caco-2 cells formed polarized columnar epithelial cells with densely packed microvilli and well developed junctional complexes. Addition of EPA enhanced FS permeability to 3.0+/-1.6-fold and lowered TEER to 0.59+/-1.2-fold vs. control with concentration dependency without cell injury (P<0.01-0.05). OA, AA or LA did not change, but ALA enhanced tight junction permeability. Indomethacin and AA861 normalized the changes mediated by EPA. CONCLUSIONS: EPA affects tight junction permeability in intestinal monolayer cells specifically and concentration dependently via cyclooxygenase and lipoxygenase products.

Caco-2 Cells↗
PubMed2001

Structure elucidation of ostreocin D, a palytoxin analog isolated from the dinoflagellate Ostreopsis siamensis.

The structure of ostreocin D, a palytoxin analog isolated from the marine dinoflagellate Ostreopsis siamensis, was found to be 42-hydroxy-3,26-didemethyl-19,44-dideoxypalytoxin by detailed 2D NMR analyses of intact ostreocin D and its ozonolysis products. Partial stereochemical assignments were done. This result indicates that the dinoflagellate O. siamensis is one of the biogenetic origins of palytoxin.

Acrylamides↗
PubMed2001

[A case of clinically multifocal renal cell carcinoma].

A 61-year-old woman was diagnosed with a renal tumor of the left kidney by ultrasound sonography during a health check-up. Computerized tomography (CT) and colored Doppler ultrasound sonography demonstrated two hypervascular tumors as typical renal cell carcinomas. A radically nephrectomized specimen was step-sectioned. Four tumor nodules were detected macroscopically, and 47 small nodules were detected microscopically, showing the clear cell type and alveolar growth pattern. Then all nodules including the 47 small nodules were diagnosed renal cell carcinoma.

Carcinoma, Renal Cell↗
PubMed2001

[Clinical effects of a 3-month formulation LH-RH agonist (Zoladex LA 10.8 mg depot) in patients with prostate cancer].

Pharmacodynamics (PD), anti-tumor effects, safety and pharmacokinetics of a 3-month formulation of goserelin (Zoladex LA 10.8 mg depot: "10.8 mg depot") were investigated in a collaborative multicenter study. Study participants were 40 Japanese patients with prostate cancer comprising 20 untreated patients and 20 switch patients who had been receiving Zoladex 3.6 mg depot for 3 months or longer. Serum testosterone levels, serum LH levels, prostate-specific antigen (PSA) levels and drug concentrations were measured until 12 weeks after a single subcutaneous dose of 10.8 mg depot. Anti-tumor effects were evaluated by means of changes in the tumor lesions and the PSA levels at 12 weeks. After administration to the untreated patients, 10.8 mg depot reduced serum testosterone to the castrate range within 4 weeks and the reduction was maintained for up to 12 weeks. In the switch patients, serum testosterone suppression that had been produced by previous treatment with Zoladex 3.6 mg depot was maintained for up to 12 weeks following 10.8 mg depot administration. The anti-tumor effect at 12 weeks was 90.0% including partial response cases. The ratio of PSA normalization at 12 weeks was 75.0%. Fifty-seven adverse reactions were observed in 27 of the 40 patients (67.5%), but none were clinically significant. Although a disease flare presented as urinary retention in 1 of the untreated patients, all patients completed the study. Serum goserelin was detected up to 12 weeks after the administration of 10.8 mg depot. In conclusion a single dose of 10.8 mg depot showed a satisfactory PD-effect and brought about clinical efficacy persisting for at least 12 weeks and was well tolerated in patients with prostate cancer.

Adenocarcinoma↗
PubMed2001

[A case of adult Wilms' tumor].

Wilms' tumor is very rarely found in adults and there are no established treatment guidelines for such tumors in adults. A 56-year-old woman was referred to our hospital for further examination of macroscopic hematuria. Computed tomography scan revealed a large right renal mass with enlarged lymph nodes. Angiography showed a hypovascular tumor. She underwent right nephrectomy and resection of lymph node metastasis with a diagnosis of malignant renal tumor. Histopathological examination revealed nephroblastoma with lymph node metastasis. The disease was classified as stage III according to the National Wilms' Tumor Study classification. The patient received adjuvant chemotherapy consisting of ifosfamide, cisplatin, and etoposide. This protocol was selected because of the published poor results with the standard Wilms' tumor chemotherapeutic agents when used in adults. She remained without tumor recurrence as of six months after surgery. Development of better therapeutic approaches to adult Wilms' tumor is awaited.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

[Teratogenicity study of N-methylphenyl-N'-methylphenyl-p-phenylenediamine (MMPD) in rats by oral administration].

Teratogenicity of N-methylphenyl-N'-methylphenyl-p-phenylenediamine (MMPD), a rubber antioxidant, was examined in Wistar rats. MMPD was given to pregnant rats by gavage once a day from day 6 through day 15 of pregnancy at doses of 0, 2, 4 and 8 mg/kg/day. The pregnant rats were sacrificed on day 20 of pregnancy and their fetuses were examined. MMPD was not maternal toxicity at any dose. MMPD did not affect growth or morphological development of fetuses. MMPD caused early embryonic death at 8 mg/kg. It was concluded from these results that the no-observed-adverse-effect level was 2 mg/kg/day for rat fetuses, and 8 mg/kg/day or higher for pregnant rats. The teratogenicity of MMPD was inconclusive due to its embryo-fetal lethality.

Abnormalities, Drug-Induced↗
PubMed2000

Sex differentiation and mRNA expression of P450c17, P450arom and AMH in gonads of the chicken.

The present study was conducted to reveal effects of in ovo injection of nonsteroidal aromatase inhibitor (Fadrozole) or estradiol at day 3 of incubation on mRNA levels of P45017alphahydroxylase (P450c17), P450 aromatase (P450arom) and anti-Müllerian hormone (AMH) in the chicken gonads. The mRNA levels in the gonads at days 4-8 of incubation were assessed by in situ hybridization analysis using digoxigenin labeling method. The in situ hybridization data were analyzed by relative expression of specific hybridizable signals of each mRNA corrected by the non-specific background by employing an image analyzer. P450c17 mRNA expression increased rapidly at day 6 of incubation in the male but decreased thereafter. In contrast to the transient expression in the male, the expression was gradually increased in the female. P450arom mRNA was not expressed in the male but was detectable in the female as early as day 6 and increased subsequently with days of incubation. AMH mRNA was expressed as early as day 5 of incubation followed by a sharp increase on day 6, which was maintained in the male thereafter. In contrast, the female showed very little expression. The injection of Fadrozole caused no effect on P450c17 mRNA expression, while it suppressed P450arom mRNA expression but increased AMH mRNA expression in the female. In contrast, the injection of estradiol induced P450arom mRNA expression significantly but suppressed AMH mRNA expression in the male. These results indicate that expression of P450arom and AMH is sexually dimorphic and is reciprocally regulated during early ontogenic life in chicken gonads.

Animals↗
PubMed2000

Early results of LH-RH agonist treatment with or without chlormadinone acetate for hormone therapy of naive localized or locally advanced prostate cancer: a prospective and randomized study. The Prostate Cancer Study Group.

BACKGROUND: The majority of patients with localized and some cases of locally advanced prostate cancer undergo radical prostatectomy. However, radical prostatectomy cannot always be selected for those patients. In this situation, primary hormone therapy is an alternative treatment option. We have designed a prospective randomized study of the effects of primary hormone therapy for such patients. METHODS: A total of 151 patients with T1b, T1c, T2a, T2b or T3a prostate cancer who were not scheduled for radical prostatectomy were enrolled into this study. Patients were randomly allocated into two groups; Group I received luteinizing hormone-releasing hormone (LH-RH) agonist monotherapy (leuprorelin acetate depot, 3.75 mg monthly) and Group II received LH-RH agonist in combination with chlormadinone acetate (100 mg/day). Effects on serum prostate-specific antigen level, progression-free survival and survival were observed for 2 years. RESULTS: The reasons why radical prostatectomy was not scheduled were poor risk for surgery (38%), patient's wish (32%) and physician's recommendation (30%). After 12 weeks of treatment, 49% of the patients in both groups showed a complete response (CR). Of the patients showing a partial response (PR) after 12 weeks of treatment, 25% in Group I and 52% in Group II improved to CR 1 year later (p<0.05). Group II showed a longer progression-free survival (p <0.05). Progression-free survival rates were 62% (Group I) and 91% (Group II) in T2b patients and 43% (Group I) and 73% (Group II) in T3 patients. Only one patient in each group died from prostate cancer. CONCLUSIONS: Early primary hormone therapy is a reasonable treatment option for localized or locally advanced prostate cancer patients if radical prostatectomy was not scheduled. Chlormadinone acetate showed an additive effect with LH-RH agonist, at least in 2 years' observation.

Aged↗