Biomedical subjects

I Sato

Publications and source records attributed to I Sato.

At least 181 records · Page 10Linked to original sources

PubMed1997

Tonic fiber in Mauremys (Clemmys) japonica jaw muscle.

The jaw muscles of a turtle [Mauremys (Clemmys) japonica (MCJ)], have been analyzed for the histochemical characteristics of their fiber types. Six jaw muscles of the MCJ have been analyzed for histochemical characteristics of their fiber types. In this study, fiber types in two groups of muscles are classified; 1) fast twitch glycolytic (FG), fast twitch oxidative glycolytic (FOG), slow twitch oxidative (SO), and tonic fibers, according to the system of Putnam et al. (1980); 2) reacted differently in similar histochemical tests and classified, respectively, as various types. Especially tonic fibers constituted low percentage in the MAMP (ca., 0.3%), MI (ca., 3.9%) and MPtp (ca., 1.0%) were found. These results suggested that the tonic fiber plays a small part of the function in jaw movement.

Animals↗

PubMed1997

Distribution of macromolecular components in the muscle-bone junction of human masticatory muscles.

At the muscle-bone junction, the attachment is composed of macromolecular components that differ from those in masticatory muscles. In the temporal and lateral pterygoid muscles, numerous fine fibers form complex arrangements between collagenous bundles and the tendon-bone junctions. Collagenous bundles are directly inserted into the bone tissue at the site of the adhesive attachment. Reticular fibers are arranged irregularly and cover the collagenous bundles as a network. Numerous collagenous fibers are also tightly connected with the bundles that are found near the muscle-bone junction of the lateral pterygoid muscle. Strong or moderate staining for collagen types I, III, and V, tenascin, laminin, and fibronectin was observed in close association with the border of the bone matrix. Different distributions of these macromolecular components were found in each masticatory muscle. The results suggest that the morphological properties of the muscle-bone junction of each muscle reflect the tension or the stretch applied to a mandible bone. The distribution of macromolecular components in each muscle also reflects the form and calcification of the mandibular bone during aging.

Alveolar Process↗

PubMed1997

Quantitative morphology of dermal elastic fibers system of the human face during aging.

Human skin has various distributions and arrangements of elastic fiber (EF). Previous reports did not clearly show the distribution of EF in the face skin because of various contents during aging. In this study, a color image analyzer indicated distribution of elastic, oxytalan, and muscle fibers in human face skin. During aging the muscle fiber size and the content of the EF decreased in the modiolus and inferior labial regions of the human skin, and the ratio of the EF was lower than that of oxytalan fiber measured areas. That is, the dimension of oxytalan fiber may reflect the content of EF, and muscle has a role in the distribution of the EF in human face skin. In the deeper regions, small and large EF bundles were found near the sheath of gland and muscles. Therefore, face movement might be an important aspect to maintaining the EF content of human face skin.

Adult↗

PubMed1997

Enhancement of membrane fluidity in cholesterol-poor endothelial cells pre-treated with simvastatin.

We examined the membrane fluidity of the cholesterol-poor bovine carotid artery endothelial cells (BAEC). Cholesterol-poor BAEC were obtained by treating the cells with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors under 10% low density lipoprotein (LDL)-deficient serum condition for 2 days. Simvastatin reduced the intracellular cholesterol content significantly at a concentration of 0.1 microgram/ml. The reduction in the cholesterol content was accompanied by the enhancement of the cell membrane fluidity which was measured by a photobleaching technique. Additional data suggested that the reduction in cholesterol content referred to the reduction in the proliferation of BAEC.

Animals↗

PubMed1997

Hyperamylasemia in response to ritodrine or ephedrine administered to pregnant women.

BACKGROUND: Ritodrine and ephedrine can induce hyperamylasemia in pregnant women. The incidence of these beta-agonist-induced hyperamylasemias and their interaction on serum amylase activity are not known. STUDY DESIGN: Serum amylase activity was determined 12 to 24 hours after the administration of ritodrine alone (n = 140), ephedrine alone (n = 160), ephedrine and ritodrine simultaneously (n = 34), and ephedrine after prolonged (> or = 7 days) use of ritodrine (n = 101). RESULTS: A significantly higher incidence of hyperamylasemia (amylase > 215 IU/L) was seen in a group treated with ritodrine alone (60/140, 43 percent), ephedrine alone (54/160, 34 percent), or ephedrine plus ritodrine (24/34, 71 percent) compared with untreated pregnant women (21/426, 4.9 percent). There was no difference in the incidence of hyperamylasemia among the untreated pregnant women and women who received ephedrine after long-term ritodrine (8/101, 7.9 percent). Isozyme patterns, examined in 72 out of the 146 women with hyperamylasemia after such medications, indicated that salivary-type amylase exclusively was hypersecreted. CONCLUSIONS: Clinical doses of beta-agonists such as ephedrine or ritodrine induce hypersecretion of salivary-type amylase in approximately one-third of women who are pregnant. Desensitization to beta-agonists may occur after prolonged use of ritodrine.

Adolescent↗

PubMed1997

[Tuberculous pleuro-peritonitis showing increased levels of CA125].

A 53-year-old woman was admitted because of dyspnea and coughing of about 8 months duration. On examination she had left pleural effusion and ascites. The serum CA125 level was high (1150 U/ml) but gynecological examinations were negative. Radiological and ultrasonic studies revealed bilateral pleural effusions and ascites. Cytological and bacteriological studies of the pleural effusions and ascites were all negative. The pleural fluid was exudate with high lymphocyte counts and elevated ADA (87.4 IU/l) and CA125 (1800 U/ml). Tuberculous pleuritis was diagnosed based on the findings of sputum culture and of pleural biopsy. The latter revealed epithelioid cell granulomas and giant cells. Cells in both pleural effusion and ascites were stained with antibodies to CA125. Antituberculous chemotherapy was started and the patient responded well. Both pleural effusions and ascites decreased; the level of CA125 also decreased to the normal range in about two months.

CA-125 Antigen↗

PubMed1997

Fetal ventricular rate in case of congenital complete heart block is increased by ritodrine. Case report.

We encountered a case of fetal bradycardia (57 bpm) induced by heart block. The continuous intravenous administration of ritodrine to a mother to treat fetal brady-cardia at 28 weeks of gestation successfully increased the fetal ventricular rate by 15 bpm (from 57 to 72 bpm). Pregnancy was continued for 10 weeks, and fetal cardiac failure did not occur. The fetal ventricular rate gradually decreased to 52 bpm after discontinuation of the ritodrine infusion. It is suggested that maternal administration of ritodrine can be considered in a case of life-threatening fetal bradycardia induced by complete heart block.

Adult↗

PubMed1997

Relationship between turnover of cesium-137 and dietary potassium content in potassium-restricted mice.

The biological half-life of 137Cs and its organ distribution were investigated in mice fed various potassium-deficient diets. The biological half-life, which was 6.1 days in mice receiving the normal level of potassium, became longer as the dietary potassium content decreased, and 137Cs was hardly excreted from the body when dietary potassium content was restricted to 200 mg/kg or less. The muscle showed the highest concentration of 137Cs in both mice that had sufficient amounts of potassium and those that were potassium-deficient. Clearance of 137Cs from tissues was generally suppressed when mice were fed a potassium-deficient diet, but the relative distribution pattern of 137Cs was not affected by dietary potassium content. These results suggest that dietary potassium intake, which may vary with eating habits, affects the biological half-life of 137Cs in humans.

Animals↗

PubMed1997

Digitalization of the mother in treating hydrops fetalis in monochorionic twin with Ebstein's anomaly. Case report.

Hydrops fetalis thought to be due to Ebstein's anomaly was seen at 22 weeks' gestation in one of two fetuses with a monochorionic placenta. Hydrops was treated with maternal digitalization and resolved by the 28th week of gestation. Hydrops did not recur while maternal digitalization continued. A clinical diagnosis of twin-to-twin transfusion syndrome required termination of the pregnancy at 33 weeks of gestation. The twin with Ebstein's anomaly died 22 hours after birth. The other twin survived and was normal at 19 months of age. Thus, administration of digitalis to the mother controlled hydrops fetalis in one fetus, and ultimately led to the survival of the healthy infant.

Adult↗

PubMed1997

[Effect of nitrous oxide on spinal dorsal horn WDR neuronal activity in cats].

The effects of nitrous oxide (75%) on the spinal dorsal born wide dynamic range (WDR) neuronal activity were studied in either spinal cord intact or spinal cord-transected cats. Extracellular activity was recorded in the dorsal horn from single WDR neurons responding to noxious and non-noxious stimuli applied to the cutaneous receptive fields on the left bind foot pads of intact or decerebrate, spinal cord-transected (L 1-2) cats. The experiment was divided into four sections as follows: (1) When 10 micrograms of bradykinin (BK) was injected into the femoral artery ipsilateral to the recording site as the noxious test stimulus in the spinal cord-transected cat, all of 6 WDR neurons gave excitatory responses which were not depressed by 75% nitrous oxide. (2) When the injection of 10 micrograms of BK into the femoral artery ipsilateral to the recording site was used in the spinal cord-intact cat, 6 of 15 WDR neurons (40%) gave excitatory responses, which were significantly depressed by 75% nitrous oxide, and 9 of 15 WDR neurons (60%) gave inhibitory responses, which were not affected by 75% nitrous oxide. (3) When 10 micrograms of bradykinin (BK) was injected into the femoral artery contralateral to the recording site as the noxious test stimulus in the spinal cord transected cat, 6 of 12 WDR neurons gave excitatory reasons, which were not depressed by 75% nitrous oxide. (4) When the injection of 10 micrograms of BK into the femoral artery contralateral to the recording site was used in the spinal cord-intact cat, 6 of 6 WDR neurons (100%) gave responses, which were affected by 75% nitrous oxide. We have observed that nitrous oxide reduces the excitation and inhibition of dorsal born WDR neuronal activities induced by BK injection in spinal cord-intact cats, but does not reduce the excitation of those in spinal cord-transected cats. This finding confirmed that the antinociceptive effect of nitrous oxide might be modulated by supraspinal descending inhibitory control systems. In addition our result showed that the supraspinal effect of nitrous oxide was mediated not only by an increase but also a decrease in a supraspinal descending inhibition.

Action Potentials↗

PubMed1997

[Hyperalgesia induced by intrathecal administration of nitroglycerin involves NMDA receptor activation in the spinal cord].

Spinal NMDA receptors are involved in hyperalgesia and chronic pain. The activation of spinal NMDA receptor results in the production of nitric oxide in the second order neurons in the spinal cord dorsal horn. We investigated the effects of intrathecally administered nitroglycerin (NTG) which releases nitric oxide in the cell. Formalin test which reflects phasic and tonic nociception was used as a nociceptive measure in rats with chronically implanted intrathecal catheters. Intrathecal injection of NTG resulted in the increase of flinching behavior induced by formalin injection to one paw in phase 1 (phasic) and phase 2 (tonic) responses in a dose-dependent manner. Intrathecally administered NMDA antagonist, MK-801 (MK) dose-dependently inhibited the effect of NTG but the effect was significant only in the phase 2 of the formalin test. MK given after formalin injection had significantly less effect on the phase 2 response. L-NAME (NOS inhibitor), MB (guanylate cyclase inhibitor) and HB (nitric oxide scavenger) significantly antagonized the hyperalgesic effect of NTG in the phase 2 of the formalin test. These results show that nitric oxide plays an important role in producing hyperalgesia in the spinal cord acting postsynaptically as well as pre-synaptically.

Animals↗

PubMed1997

[The effects of isoflurane on the formalin-induced activity in the spinal dorsal horn of transected cat].

Although the formalin test is widely used in rodents, the electrical response to this stimulus and the effect of isoflurane on this response, has not been well understood in cats. We have therefore examined the effect of isoflurane on spinal wide-dynamic-range neuronal activity evoked by a subcutaneous (s.c.) formalin injection in cats. In decerebrate, spinal cord-transected cats (L 1-2), a s.c. injection of formaldehyde solution (0.05 ml; 5%) was performed in the receptive fields of spinal wide-dynamic-range neurons at the hind paw. Isoflurane (1.5%) inhalation was given 20 mins prior to formalin injection or 5 mins after the formalin injection. The formalin injection elicited an immediate and continuous discharge or burst activity in the neurons that lasted at least 90 min. Inhaled isoflurane was found to markedly inhibit this neuronal discharge. At 30 mins after discontinuing of isoflurane, the neuronal activity in both groups recovered to approximately 55% of the control value. These results suggest that formalin injection will reliably produce a continuous burst of neuronal activity in the spinal dorsal horn of cats, and that this activity can be markedly reduced by isoflurane. The ability of isoflurane to inhibit this neuronal response was not temporally related to the formalin injection.

Administration, Inhalation↗

PubMed1996

Carnitine transport defect in fibroblasts of juvenile visceral steatosis (JVS) mouse.

Juvenile visceral steatosis (JVS) mice are associated with systemic carnitine deficiency (Kuwajima, et al., 1991). In order to investigate the cause of this deficiency, we compared fibroblast carnitine transport activities in normal mice and JVS mice. The kinetic analysis showed that in formal fibroblasts, the Km and Vmax values for saturable uptake was 15.6 microM and 2.56 pmol/min/mg protein, respectively. In JVS fibroblasts, however, saturable uptake was not observed. There was no great difference in the linear component of uptake between normal and JVS fibroblasts. At the physiological concentration (50 microM) of carnitine, the fibroblast carnitine transport activity in JVS mice was decreased to 18% of that in normal mice. Thus there is hardly any carnitine transport activity in the fibroblasts of JVS mice, indicating that the JVS mouse can be regarded as an animal model of primary carnitine deficiency.

Animals↗

PubMed1996

Reestimating date of delivery in multifetal pregnancies.

OBJECTIVE: To clarify the optimal estimated date of delivery for multifetal pregnancies. DESIGN, SUBJECTS, AND SETTING: A retrospective study of all 88,936 infants born of multifetal pregnancies and all 6,020,542 infants born of singleton pregnancies that occurred at 26 weeks or more of gestation between 1989 and 1993 in Japan. MAIN OUTCOME MEASURE: Incidence of stillbirth and early neonatal death according to gestational age at delivery. RESULTS: The mean +/- SD duration of pregnancy was 37.0 +/- 2.7 weeks for multifetal pregnancies and 39.6 +/- 1.6 weeks for singleton pregnancies. In multifetal pregnancies, the incidence of stillbirth and of early neonatal death gradually declined until 37 to 38 weeks' gestation and then increased. These parameters in singleton pregnancies declined until 39 weeks' gestation before increasing. The lowest incidence of perinatal death (Stillbirth plus early neonatal death) seen at 38 weeks' gestation in multifetal pregnancies corresponded to that seen at 43 weeks' gestation in singleton pregnancies (10.5 vs 9.7 per 1000 infants). The fist of perinatal death was more than 6 times as high for fetuses of multifetal pregnancies born at 37 weeks or later than for singleton fetuses born at 40 weeks or later (relative risk, 6.6; 95% confidence internal, 6.1 - 7.1). CONCLUSION: Fetuses of multifetal pregnancies are at an increased risk of death after reaching the normative gestational age for singleton pregnancies. Limiting the estimated date of delivery to 37 to 38 weeks may be appropriate in multifetal pregnancies.

Delivery, Obstetric↗

PubMed1996

Purkinje cells express neuronal nitric oxide synthase after methylmercury administration.

To study the effects of chemical injury on the cerebellar nitric oxide synthase (NOS), we administered methylmercury chloride subcutaneously to mice, 10 mg/kg/day for 9 days. In the methylmercury-treated cerebellum. Purkinje cells were positive both for NADPH-diaphorase and for neuronal NOS. Calcium-dependent NOS activity was increased to 160% of the controls. The present study suggests the ability of Purkinje cells to produce NO through the expression of neuronal NOS.

Animals↗

PubMed1996

Lipopolysaccharide-induced nitric oxide synthase activity in cultured cerebellar granule neurons.

We examined the inducible form of nitric oxide synthase (iNOS) activity in cerebellar primary cultures enriched with granule neurons. Treatment with lipopolysaccharide (LPS) for 24 h was performed in two different cultures in which the survival of neurons was controlled by the levels of extracellular K+. Treatment of the granule neurons with the contaminating non-neuronal cells (< 5%) in a high K+ (25 mM) -containing culture medium with LPS induced four-fold NOS activity compared to that of the control, and the induced NOS activity was calcium-independent. LPS did not induce the NOS activity at all in the contaminating non-neuronal cells alone which were obtained by eliminating all the granule neurons from the culture by lowering the K+ concentration (5 mM). We conclude that the LPS-activated granule neurons can express iNOS activity and that this induction is not attributable to the contaminating nonneuronal cells.

Animals↗

PubMed1996

Glutathione peroxidase activity in endometrium: effects of sex hormones and cancer.

The aim of this study was to determine whether glutathione peroxidase (GSH-Px) activity in endometrial tissue is regulated by sex hormones and to compare the GSH-Px activity of normal and cancerous endometrium. The localization of GSH-Px in human normal endometrium and endometrial cancer was determined immunohistochemically. GSH-Px activity was assayed in endometrial tissue obtained from women with endometrial cancer and age-matched controls, as well as in rat uterine tissue. GSH-Px immunoreactivity was localized in the glandular epithelium of normal human endometrium and reached a maximum in the late proliferative and early secretory phases of the menstrual cycle. In spayed rats, uterine GSH-Px activity was significantly increased by exogenous estrogen (P < 0.01) and significantly reduced by exogenous progesterone (P < 0.01). GSH-Px activity in endometrial cancer tissue was significantly higher (P < 0.01) than that in endometrial tissue from age-matched healthy controls. Among endometrial cancer tissues, a significant increase in GSH-Px activity was associated with well-differentiated rather than moderately or poorly differentiated adenocarcinoma (P < 0.01), with slight rather than marked myometrial invasion (P < 0.01), and with the presence of concurrent endometrial hyperplasia (P < 0.01). These results show that endometrial GSH-Px activity is regulated by sex hormones, being stimulated by estrogen and suppressed by progesterone, and that the level of GSH-Px activity in endometrial cancer tissue may be a significant prognostic factor.

Adenocarcinoma↗

PubMed1996

The problem of relating fetal outcome with breech presentation to mode of delivery.

We retrospectively analyzed 546 consecutive singleton pregnancies with breech presentations that ended at > or = 36 weeks of gestation for the relationship between the intended mode of delivery and fetal outcome. Twelve patients were excluded from the analysis because these infants had major malformations. Of the 534 remaining patients, 124 (23%) were delivered by elective cesarean section. The other 410 women (77%) went into spontaneous labor. Intrapartum emergency cesarean section was required in 112 (27%) of these 410 women; the other 298 (73%) were delivered vaginally. There were 5 poor neonatal outcomes: 3 perinatal deaths and 2 cases of cerebral palsy probably due to intrapartum asphyxia. The risk of poor outcome was thus 1.2% (5/410), in the intended vaginal delivery group vs. no such outcome in the group of 124 patients that had an elective cesarean section. Three of 5 infants with poor outcome were actually born by emergency cesarean section and comparisons of results according to ultimate method of delivery rather than according to intended method of delivery may be misleading and in our case would have been biased against cesarean section.

Asphyxia Neonatorum↗