Search PubMed⌕ Search

Biomedical subjects

A Sato

Publications and source records attributed to A Sato.

At least 181 records · Page 10Linked to original sources
PubMed2000

Characterization of an early decline in baseline plasma glucose concentration after acute insulin elevation during euglycemic hyperinsulinemic clamp in patients with type 2 diabetes mellitus.

To investigate the contribution of the liver to whole-body insulin resistance in patients with type 2 diabetes mellitus, we analyzed the early decline (slope "a") in the baseline plasma glucose level following acute hyperinsulinemia in the initial phase of a euglycemic hyperinsulinemic clamp study, rather than using an isotope-dilution method. Slope "a" was comparable among groups of diabetic and non-diabetic subjects, and did not correlate well with glucose infusion rate (GIR), an index of peripheral (primarily skeletal muscle) insulin resistance. In contrast, slope "a" was significantly lower in obese (BMI > 25) type 2 diabetic patients compared with their non-obese counterparts, consistent with the general belief that obesity is a condition of insulin resistance in liver as well as in peripheral tissues. A subset of six insulin-resistant (nearly zero GIR) type 2 diabetic patients (pubertal adolescents) demonstrated a markedly blunted slope "a". Their insulin resistance (GIR) substantially recovered concomitant with an increase in slope "a" after pretreatment with somatostatin analogue in two cases studied, suggesting possible suppression of hepatic glucose production through lowering of plasma glucagon concentrations. Furthermore, slope "a" correlated significantly (r = -0.480, p<0.0001) with HOMA index (FPG x FIRI), the latter being recently regarded as an index of hepatic insulin resistance. These data showed that slope "a" obtained from euglycemic hyperinsulinemic clamp may be a clinically useful index of hepatic insulin resistance rather than an index of peripheral insulin resistance.

Adolescent↗
PubMed2000

Effects of nicotine on blood flow and delayed neuronal death following intermittent transient ischemia in rat hippocampus.

A cholinergic neural vasodilative response in the cerebral cortex and hippocampus, independent of metabolic vasodilation, was recently demonstrated by activating the nicotinic acetylcholine receptors (nAChRs) via activation of cholinergic neurons originating in the nucleus basalis of Meynert and septal complex in the basal forebrain and projecting to the cortex and hippocampus (see reviews by Sato A and Sato Y: Neurosci Res 14: 242--274, 1992; Sato A and Sato Y: Alzheimer Dis Assoc Disord 9: 28--38, 1995). In the present study, we aimed to examine whether an increase in regional blood flow in the hippocampus (Hpc-BF) following stimulation of the nAChRs by i.v. injection of nicotine could improve the delayed death of the hippocampal neurons following transient ischemia in rats. Hpc-BF was measured by using a laser Doppler flowmeter. During intermittent (every 2 min) transient occlusion for a total of 6 min of bilateral carotid arteries besides permanent ligation of bilateral vertebral arteries, Hpc-BF decreased to about 16% of the preocclusion level, and 5 or 7 d later, after the occlusion, delayed neuronal death occurred in approximately 70% of the CA1 hippocampal neurons. Hpc-BF was increased dose-dependently by injection of nicotine (30--100 microg/kg, i.v.), independent of mean arterial pressure. Nicotine (30--100 microg/kg) administered 5 min before occlusion slightly but significantly attenuated the occlusion-induced decrease in Hpc-BF. The delayed death of the CA1 hippocampal neurons occurring after transient occlusion was attenuated by pretreatment with nicotine (30--100 microg/kg) to approximately 50% of the total neurons. The results indicate that nAChR stimulation-induced increases in Hpc-BF can protect against ischemia-induced delayed death of hippocampal neurons.

Animals↗
PubMed2000

Randomized controlled trial of exercise training for older people (Sendai Silver Center Trial; SSCT): study design and primary outcome.

Physical exercise is expected to improve and maintain physical function in older people, thus promoting health and preventing or postponing the onset of disability in later life. The Sendai Silver Center Trial (SSCT) was a randomized controlled trial designed to evaluate the efficacy of exercise training among healthy free-living older people. Sixty-five eligible participants, aged from 60 to 81 years, were randomly allocated to an exercise group or a control group. The subjects in the exercise group were asked to attend training classes at the Sendai Silver Center, a municipal health and welfare facility in the center of Sendai City, at least twice a week for 25 weeks. Each training class, lasting two hours, started with a warm-up session, followed by an endurance session with a bicycle ergometer, and a resistance exercise training session using rubber films, and ended with a cool-down session. The subjects in the control group were asked to attend recreational classes at the Center twice a month. There were no drop-outs or accidents during the intervention. Comparison of maximum oxygen consumption (VO2max) before and after the 25-week intervention revealed a significant increase in the exercise group (2.1 ml/kg/min) but no significant change in the control group. Our result is equivalent to the participants becoming younger in aerobic capacity by five years after six months of exercise training.

Aged↗
PubMed2000

[Quantitative changes of elastin, fibrillin and collagen in abdominal aortic aneurysms].

To examine quantitative changes of elastin, fibrillin and collagen in abdominal aortic aneurysms, including ruptured abdominal aortic aneurysms (RAAA), inflammatory abdominal aortic aneurysms (IAAA) and abdominal aortic aneurysms (AAA) were measured. Items measured included the desmosine content of the aorta (desmosine 1) or of the elastin fraction (desmosine 2), fibrillin content in the aorta, hydroxyproline in the aorta, collagen percent and elastin percent, and were compared with control samples from the nonaneurysmal aortic segments. The elastin contents (desmosine 2) in RAAA, IAAA and AAA were significantly lower than those of controls. The content of the desmosine 2 from IAAA and AAA did not show a negative association with Ca. The fibrillin contents of the aorta from RAAA, IAAA and AAA were significantly higher than those of controls. The collagen content in the RAAA aorta was significantly higher than that of controls. There was a correlation of the ratio of fibrillin to elastin components (fibrillin/desmosine 1 or fibrillin/desmosine 2 or fibrillin/elastin%) and the ratio of collagen to elastin components (collagen/desmosine 1 or collagen/desmosine 2 or collagen/elastin%). These results indicated that increasing fibrillin and collagen might be a complementary result of decreasing elastin crosslinks in the aorta. This phenomenon was markedly in RAAA.

Aged↗
PubMed2000

The value of pre-operative diagnostic procedures for cervical involvement in uterine corpus carcinoma.

OBJECTIVE: To assess the value of procedures for pre-operative diagnosis of cervical involvement of uterine corpus carcinoma. MATERIALS AND METHODS: Four diagnostic procedures, including cervical cytology, endocervical curettage (ECC), magnetic resonance imaging (MRI), and hysteroscopy, were performed for diagnosis of cervical involvement in 60 patients with uterine corpus carcinoma. The preoperative diagnosis based on results obtained using by each procedure was retrospectively compared with the diagnosis based on histological examination of surgical specimens. Data were analyzed according to the standard definition of sensitivity, specificity, positive predictive value and negative predictive value. RESULTS: Cervical involvement was confirmed in 18 patients (30%). ECC showed high sensitivity (90.9%) and specificity (88.9%). Cervical cytology showed high specificity (88.6%). MRI showed very high specificity (99.2%) and high sensitivity (88.5%) in cases with cervical stromal invasion. CONCLUSION: Cervical cytology and MRI are useful for excluding cervical involvement. ECC is useful for positive diagnosis. MRI may be useful for cases with stromal invasion. The use of a combination of several procedures is essential for obtaining an accurate diagnosis of cervical involvement in cases of uterine corpus carcinoma.

Adult↗
PubMed2000

Myxoid leiomyosarcoma of the uterus.

A 70-year-old, menopausal Japanese woman with large uterine tumor underwent total hysterectomy. Microscopic examination revealed a myxoid leiomyosarcoma with 5 to 6 mitoses/10 high power field (HPF). Immunohistochemically, the tumor cells reacted with desmin, suggesting that they are derived from uterine smooth muscle cells. The patient was treated with the combination chemotherapy consisting of cisplatin, adriamycin and cyclophosphamide, and she has been free from disease for 70 months after the operation.

Aged↗
PubMed2000

Predominant contribution of the G protein-mediated mechanism to NaF-induced vascular contractions in diabetic rats: association with an increased level of G(qalpha) expression.

The purpose of this study was to determine the mechanism responsible for alterations in NaF-induced contractions of blood vessels from streptozotocin-induced diabetic rats. In the presence of AlCl(3), NaF (>/=7.5 mM) produced significantly greater contractions in diabetic aorta and mesenteric artery compared with age-matched controls. Pretreatment with 1 microM nifedipine eliminated the enhanced contractile responses of diabetic vessels to NaF, resulting in no difference in the magnitude of NaF-induced contractions between control and diabetic vessels. In the presence of 100 microM deferoxamine, an Al(3+) chelator, NaF-induced contractions of diabetic vessels were markedly attenuated, whereas only the responses to lower concentrations of NaF were reduced in control vessels. No significant difference was found in the peak amplitude of transient contractions induced by 10 microM cyclopiazonic acid between control and diabetic vessels. The addition of 10 microM okadaic acid produced attenuated contractions in diabetic vessels. These findings indicate no involvement of the inhibitory effects of NaF on endoplasmic reticular Ca(2+)-pump ATPase and protein phosphatases in the genesis of the enhanced responsiveness of diabetic vessels to NaF. Western blot analysis showed a 2.5-fold increase in the expression of G(qalpha) in diabetic aortic membranes. In contrast, the G(ialpha) level was modestly decreased and the G(salpha) and G(betagamma) levels were unchanged in diabetes. The present results suggest that enhanced vascular contractions to NaF in diabetes is attributed predominantly to a G protein-mediated Ca(2+) channel activation that results from markedly increased G(qalpha) expression in vascular tissues under this pathological state.

Aluminum Chloride↗
PubMed2000

[Basic and clinical aspects of bronchus-associated lymphoid tissue].

Human mucosal membrane surfaces have a distinct protective mechanism that is specifically designed to produce secretory IgA. In the airway, bronchus-associated lymphoid tissue (BALT), is known to be an inductive site of secretory IgA. BALT is a lymphoid aggregate located in the submucosal area of bronchioles, and plays a central role in airway mucosal immunity by inducing the accumulation of secretory IgA-producing cells. Although previously it had been unclear whether BALT is present in the human lung, we demonstrated the expression of BALT in patients with diffuse panbronchiolitis, chronic hypersensitivity pneumonitis, and collagen disease-associated lung diseases. BALT was shown to elevate serum IgA levels and in other ways to have an influence on the symptoms and signs in patients with these pathologic conditions. We also demonstrated that continuous inhaled antigenic stimulation as well as the local production of interleukin-4 and other cytokines promote BALT development, which, in turn, may give rise to BALToma, a type of primary pulmonary mucosa-associated lymphoma.

Animals↗
PubMed2000

[Absence of cross resistance between an irinotecan plus cisplatin combination and raltitrexed (ZD1694) in two patients with advanced colorectal cancer].

Two patients with advanced colorectal cancer were consecutively administered two different chemotherapeutic regimens. The first patient showed an initial response to combination treatment with irinotecan plus cisplatin, but then progressed. He subsequently responded to treatment with a novel thymidylate synthase (TS) inhibitor, raltitrexed. The second patient, who progressed after exhibiting a response to raltitrexed, subsequently responded to irinotecan/cisplatin combination therapy. In conclusion, no clinical cross resistance between the regimens of irinotecan/cisplatin combination therapy and raltitrexed was observed in these patients with advanced colorectal cancer.

Antimetabolites, Antineoplastic↗
PubMed2000

[An outbreak of pulmonary tuberculosis in the dormitory of construction labors suspected to have been due to exogenous reinfection].

We report an outbreak of pulmonary tuberculosis (TB) in a dormitory of construction labors, and this outbreak is suspected to have been caused by exogenous reinfection, based on the restriction fragment length polymorphism (RFLP) analysis and other findings. After a patient entered our hospital with active TB, 12 new other patients were discovered by contacts examination. These patients lived together in the same dormitory. They were all male and single, and were aged from 43 to 63 years old. Except one patient (No. 3) previously treated for TB for three months about 2 years ago and was suspected to be the index case of this outbreak, 12 other patients did not have a medical history of TB. The bacilli cultured from 11 patients (No. 1-11) were tested by RFLP analysis, three patterns were identified, and the fingerprints from 9 patients (No. 1-9) were identical, and the patterns of incomplete resistance of some antituberculous drugs were quite similar between No. 1-9 and No. 12 and between No. 10 and No. 13, respectively. The locations of the main lesions of TB on chest X-ray pictures were the apico-posterior segments of bilateral upper lobes. No signs suspected to indicate primary tuberculosis were detected. Considering the rate of tuberculous infection in Japan among the middle age and above as well as the identical RFLP results, most of patients in this outbreak except the index case No. 3 were suspected to have TB due to the exogenous reinfection.

Adult↗
PubMed2000

[A case of primary tuberculosis, with subpleural infiltrative shadow, hilar lymphadenopathy perforated into bronchus, causing tuberculous pneumonia].

A 47-year-old asymptomatic female was referred to our outpatient department with pulmonary infiltration in the left S6. PPD skin test revealed 12 x 11 mm redness. The infiltration disappeared without treatment. Hilar lymphadenopathy appeared 2 months after the first visit. In 6 months after the first visit, the hilar lymphadenopathy disappeared without treatment, but infiltration appeared in the left S6 (different site to that of the first visit). A repeated PPD revealed 47 x 40 mm redness and 20 x 15 mm induration. Bronchoscopy revealed a polipoid lesion at the orifice of left B6, MTD (Mycobacterium tuberculosis direct test) was positive from the bronchial washing of left B6. She was diagnosed as tuberculosis based on the courses and radiographic appearances. After antituberculous chemotherapy, the pulmonary infiltration and the polipoid lesion at the orifice of left B6 improved.

Bronchial Diseases↗
PubMed2000

The long-term effect of low-carbohydrate/high-fat diet on the development of diabetes mellitus in spontaneously diabetic rats.

The long-term effect of low-carbohydrate/high-fat diets on the development of diabetes mellitus was studied in Otsuka Long-Evans Tokushima Fatty strain (OLETF) rats. Four groups of spontaneously diabetic (type 2) male rats at 10 weeks of age were pair-fed semi-purified powder diets containing different amounts of carbohydrate (80%, 60%, 40%, 20% of total calories) for 30 weeks. The carbohydrate content was isocalorically substituted for the fat content in the diet. At the onset of experimental feeding (10 weeks of age), an oral glucose tolerance test (OGTT) was normal in each group. After 15 weeks of the test diet feeding there was no significant difference in the glucose tolerance among the 4 groups, although most of the rats were diabetic. The body weight increased with the decrease of the carbohydrate intake and increase of the fat intake (p <0.05), and the difference increased in proportion to age (p<0.05). The severity of diabetes mellitus was also increased along with the lower carbohydrate intake and higher fat intake, when the carbohydrate intake was less than 60% (in energy). On the other hand, there was a significant increase in the 20% group in the postload plasma insulin levels as compared with the other 3 groups at 40 weeks of age. Fasting plasma free fatty acid levels were increased in the lower carbohydrate content groups (20% and 40%) as compared with the higher carbohydrate content groups (60% and 80%) at the end of the experiment. Impairment of insulin secretion may be the cause of glucose intolerance induced by low carbohydrate intake rather than insulin resistance. These findings suggest that low-carbohydrate/high-fat diet aggravates diabetes mellitus in genetically diabetic rats, and that the development of diabetes mellitus is associated with the activation of the glucose-fatty acid cycle.

Animals↗
PubMed1999

Self-Assembly of a Radially Functionalized Hexagonal Molecule: Hexakis(4-hydroxyphenyl)benzene.

Two different porous hydrogen-bonded networks are formed by self-assembly of the radially substituted host 1. In the network of type A, formed by 1 small middle dot4 Et(2)O, all OH groups of 1 are involved in hydrogen bonding, and the molecular sheets are stacked without translation to generate extended channels that accommodate the Et(2)O molecules. Four OH groups of 1 are involved in the type B network of 1 small middle dot4 DMF, and lateral translation of the sheets in an ABAB sequence generates large chambers, each of which contains four DMF molecules.

Journal Article↗