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Biomedical subjects

Y Otsubo

Publications and source records attributed to Y Otsubo.

At least 37 records · Page 2Linked to original sources
PubMed1999

Prediction of oligohydramnios in prolonged pregnancy.

A decrease in amniotic fluid in prolonged pregnancy is associated with increased fetal morbidity. However, few investigations have been reported on the prediction of this condition. Fetal renal arterial pulsatility index (PI), hourly fetal urine production rate (HFUPR) and amniotic fluid index (AFI) at 39 weeks were studied in 51 singleton pregnancies with (n = 14) and without oligohydramnios (AFI < 5, n = 37) in prolonged pregnancy. There was no difference in the average fetal renal arterial PI and HFUPR between the oligohydramnios group and the normal group. However, the average AFI in the oligohydramnios group was 7.5 +/- 0.9, which was lower than that in the normal group (p < 0.05). We speculated that AFI value at 39 weeks is useful for predicting the incidence of oligohydramnios in prolonged pregnancy.

Female↗
PubMed1999

Fetal middle cerebral artery Doppler waveforms in twin-twin transfusion syndrome.

The aim of this study was to compare the fetal middle cerebral artery (MCA) Doppler waveforms in growth-retarded twin fetuses with (n = 11) and without (n = 24) twin-twin transfusion syndrome (TTTS). Umbilical artery (UA) and fetal MCA Doppler velocity waveforms were recorded on admission. The mean values of the UA pulsatility index (PI) of smaller twin fetuses with and without TTTS were significantly higher than those of normal singleton pregnancies. The mean values of the MCA PI of smaller twin fetuses in the TTTS group (+0.7 +/- 1 SD) were significantly higher than those of normal singleton pregnancies on admission, and these levels did not markedly change following amniocentesis. On the other hand, the values of the MCA of the growth-retarded fetuses without TTTS (-0.9 +/- 1 SD) were significantly lower than those of normal singleton pregnancies. Our findings suggest that measurement of fetal MCA PI is a useful method to assess growth-retarded fetuses in monochorionic twin pregnancies.

Adult↗
PubMed1999

Fetal brain death and Dandy-Walker malformation.

The diagnosis of brain death by Doppler ultrasonography and magnetic resonance imaging is reported in a fetus at 23 weeks' gestation. This is believed to be the first instance in which brain death has been shown in a premature fetus with a brain-stem anomaly.

Abortion, Spontaneous↗
PubMed1998

Effect of Adsorption Affinity of Polymers on the Viscosity Behavior of Suspensions.

The viscosity behavior of suspensions flocculated by bridging was examined as a function of adsorption affinity of polymers for the particle surface. The polymer chains having strong affinity form fragile bridges between particles as a result of irreversible adsorption. Because the flocs are broken down on the application of shear fields, the flow is shear-thinning. The decrease in the adsorption affinity by the addition of small amounts of surfactant causes the reversible adsorption. The suspensions flocculated by reversible bridging are Newtonian at low shear rates because the polymer bridges are forming and breaking in a quiescent state. When the coil size is comparable to the particle diameter, the suspensions show shear-thickening flow in high shear fields. The shear thickening is induced by the elastic effects of extended bridges. The flow profiles of suspensions flocculated by polymer bridging are controlled by changing the adsorption affinity of polymers. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Evidence for mechanisms of the acute-phase response to endotoxin in late-gestation fetal goats.

OBJECTIVE: The aim of this study was to evaluate the relationship between febrile response to fetal endotoxin administration and fetal plasma endogenous pyrogen, tumor necrosis factor-alpha, the possible putative pyrogen mediator prostaglandin E2, and the endogenous antipyretic arginine vasopressin in late-gestation pregnant goats. STUDY DESIGN: Changes in fetal core temperature, plasma tumor necrosis factor-alpha, prostaglandin E2, and arginine vasopressin levels were measured after administration of Escherichia coli endotoxin (70 microg/kg of fetal weight) to 10 fetal goats in late gestation. RESULTS: Fetal body temperature did not rise after endotoxin administration. Fetal plasma tumor necrosis factor-alpha and arginine vasopressin increased to 87.5 +/- 15.2 pg/mL and 25.1 +/- 4.8 pg/mL, respectively, after 1 to 2 hours (P < .05). Fetal plasma prostaglandin E2 levels did not change significantly throughout the study. CONCLUSION: The absence of a febrile response to endotoxin in late-gestation fetal goats is accompanied by a deficient responses in prostaglandin generation in the periphery and increased activity of the antipyrogen arginine vasopressin.

Acute-Phase Reaction↗
PubMed1998

Comparisons of Nitric Oxide Synthases in Normal Human Placenta from 37 to 41 Weeks Gestation: Qualitative and Quantitative Analyses.

> Objective: The purpose of this study was to determine the type of nitric oxide synthase isoform and to measure the quantities of nitric oxide synthase mRNA in the human placenta. Methods: The isoforms of nitric oxide synthase were determined in ten placentas of normal pregnant women using information regarding calcium dependence and inhibition by arginine analogs and findings from Western blot analyses and reverse transcriptase-polymerase chain reaction. Results: The activity of nitric oxide synthase was largely calcium dependent, although a small element of calcium-independent activity was observed. A stronger inhibition was shown with Nomega-nitro-l-arginine than with Nomega-monomethyl-l-arginine. On Western blots endothelial nitric oxide synthase was detected as a band of 140 kilodaltons, without evidence of inducible nitric oxide synthase. Messenger RNA of endothelial nitric oxide synthase was readily detected by reverse transcriptase-polymerase chain reaction, but that of inducible nitric oxide synthase was barely detected. The quantity of mRNA of inducible nitric oxide synthase was about 100-fold less than that of endothelial nitric oxide synthase. Conclusions: These results point to the constitutive endothelial type as the predominant isoform of nitric oxide synthase in human placenta from 37 to 41 weeks gestation, although protein and mRNA of inducible nitric oxide synthase may exist.

Journal Article↗
PubMed1997

Effect of Electrode Pattern on the Column Structure and Yield Stress of Electrorheological Fluids

For electrorheological (ER) suspensions, the aggregate structures of particles were observed in electric fields by the use of transparent cells with different electrode patterns. Although the suspension is dispersed to noninteracting particles without electric fields, many aggregates are formed on the electrode surface in electric fields. Since the dipole-dipole interactions cause chain structures of particles and equilibrium conformations of chains are always aligned with electric field, the aggregates indicate the presence of columns spanning the electrode gap. The particle concentration in columns which are developed between parallel-plate electrodes is about 22 vol %. In striped electrodes, the particles construct striped aggregates along the electrodes and no particles remain in the insulating region. The particle concentration in striped aggregates is about 35 vol %. The nonuniformity of electric field is responsible for the high particle concentration. The increase in particle concentration of column lead to the high yield stress of electrified suspension. Therefore, the ER performance of suspension as an overall response can be improved by the electrode design.

Journal Article↗
PubMed1997

Effects of insulin-like growth factor-1 on endotoxin translocation in burned rats receiving total parenteral nutrition.

The purpose of this study was to investigate the effect of insulin-like growth factor-1 (IGF-1) on the translocation of endotoxin from the gut of burned rats. Twenty-eight male Sprague-Dawley rats (7-wk-old) were subjected to 20% full-thickness scald burns and were divided into two groups. One group received 4 mg.kg-1.d-1 of IGF-1 (IGF-1 group, n = 14), and the other received saline (control group, n = 13). All rats were fed exclusively by total parenteral nutrition (TPN). On the second postburn day, rats were killed. The amount of endotoxin in the liver and spleen were measured. RNA from the terminal ileum was extracted, and Northern blot analyses of alpha-tubulin, beta-actin, cell division cycle-2 (cdc2), and immunoglobulin-A (IgA) were performed. Nitrogen balance was improved (p < 0.001), and the wet weight of intestine and its mucosa were increased significantly in the burned rats that received IGF-1. Gene expression of alpha-tubulin and beta-actin were not changed. Cdc2 was elevated (P < 0.05), but IgA was decreased (P < 0.05) in the IGF-1 group. Levels of endotoxin in the liver and spleen were significantly reduced (P<0.05) by the administration of IGF-1. A negative correlation between the levels of endotoxin in the liver and the weight of the intestinal mucosa was observed. In conclusion, IGF-1 improved nitrogen balance, promoted the proliferation of intestinal mucosa and reduced the translocation of endotoxin.

Actins↗
PubMed1997

Fetal plasma hypoxanthine level in growth-retarded fetuses before labor.

Hypoxanthine is one of the purine nucleotides and is presumed to accumulate during hypoxia and acidemia. It remains uncertain, however, whether plasma hypoxanthine concentration is a useful indicator of fetal asphyxia; and its relationship to other markers of fetal physiologic state is not clearly defined. The aim of this study was to evaluate whether the level of fetal plasma hypoxanthine is correlated with fetal hypoxia and acidosis in growth-retarded fetuses before the onset of labor. Cordocentesis was performed in 34 growth-retarded fetuses at 31-35 weeks' gestation for the measurement of umbilical venous plasma concentrations of hypoxanthine, hemoglobin and lactate concentrations, blood gases, and base deficit. Umbilical venous plasma hypoxanthine concentration was found to be increased significantly, in parallel with the degree of acidosis (r = -0.74, P < 0.05) and base deficit (r = -0.41, P < 0.05), but not to bear a significant relationship to the degree of hypoxemia or other measured variables. We conclude that increases in the plasma concentration of hypoxanthine may reflect an impaired physiological state in growth-retarded fetuses before labor.

Acid-Base Equilibrium↗
PubMed1997

Intracerebral monoamine concentration after ventriculoperitoneal shunting in the congenital hydrocephalus rat.

This study investigated the relationship between neurotransmitters and improvement of symptoms after ventriculoperitoneal shunting in congenital hydrocephalus (LEW-HYR) rats. Twenty-four patent hydrocephalus rats, aged 12-14 days, were randomly assigned to the following four groups: ventriculoperitoneal shunt group, obstructed shunt group, burr hole group, and no treatment group. In addition, six normal rats served as control group. Head to body length ratio was measured before and 7 days after the procedures. Coordination movement was evaluated on the 7th postoperative day. High performance liquid chromatography (HPLC) was used to measure the concentrations of dopamine (DA), norepinephrine (NE), serotonin, homovanillic acid (HVA), 3-methoxyl-4-hydroxyphenylenglycol, 5-hydroxy-indolacetic acid (5-HIAA), and 3,4-dihydroxyphenylacetic acid in the whole cerebral cortex, the thalamus and hypothalamus, the midbrain, the lower brainstem, the cerebellum, and the striatum. Fluorohistochemical studies were also performed. Significant improvements were observed in body proportion and coordination movement in the ventriculoperitoneal shunt group compared to the burr hole group and the no treatment group. HPLC and fluorohistochemical studies revealed that concentrations of NE in the thalamus and hypothalamus and DA in the striatum were significantly lower in the burr hole group and the no treatment group. Concentrations of HVA and 5-HIAA in the cerebellum were significantly lower in the control group. The present study indicates that ventriculoperitoneal shunting may improve the changes in concentrations of neurotransmitter in specific neurons caused by hydrocephalus, and this may contribute to the improvement of the symptoms.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1996

Optical Properties of Nonaqueous Suspensions in Electric Fields.

The optical properties of suspensions consisting of pigmented shell/polymer core composite particles dispersed in a silicone oil were studied in electric fields. In the absence of electric fields, the transmittance shows an exponential decay with sample thickness and particle concentration. The particles may be randomly dispersed in the medium. The application of electric field leads to an increase in the transmittance of suspensions. The clearing effect is very striking, especially for concentrated suspensions in a thick cell. In electric fields, the transmittance is almost independent of thickness in the range 0.15-1.1 mm and linearly decreases with increasing particle concentration. Microscopic observation shows that many discrete clusters are formed in electric fields. Based on the analysis of dipole-dipole interactions, the clusters may be composed of fully developed chains spanning the electrodes. Since the columns are aligned in the direction parallel to the optical path, the transmittance is not affected by the cell thickness. In addition, because of the increase in the cross section of the column, the transmittance shows a linear dependence on the particle concentration. The optical properties of suspensions can be explained by the column formation of particles in electric fields.

Journal Article↗
PubMed1996

Surgical management of cervicomedullary compression in achondroplasia.

Achondroplasia is often associated with cervicomedullary dysfunction. MRI sagittal imaging was performed to determine whether surgical intervention was necessary to relieve cervicomedullary compression. Cervicomedullary compression was classified into severe and mild types based on the ratios of the brain stem diameter at the foramen magnum, the site of the most severe stenosis to the diameter at the pontomedullary junction and C3 level, where it is normal. This classification was found to be closely correlated with the severity of clinical symptoms and important in determining whether surgical intervention is necessary. Moreover, since the incidence of sudden death is high in patients aged 4 years or younger with achondroplasia, surgical intervention should be considered in all such patients if cervicomedullary compression is present.

Achondroplasia↗
PubMed1995

Possible inhibitory effect of lithium on peripheral conversion of thyroxine to triiodothyronine: a prospective study.

The effect of lithium on thyroid function was studied in 18 neuroleptic-treated male chronic schizophrenic in-patients. Lithium carbonate was administered for 8 weeks at a dosage giving a mean serum level of 0.79 mmol/l. Blood was obtained just before and after 8 weeks of lithium administration to determine the serum free thyroxine (free T4) levels, free triiodothyronine (free T3) levels and thyrotropin (TSH) levels. Overall, free T4 and TSH levels significantly increased whereas free T3 levels did not change. Two (11%) patients had abnormally increased free T4 levels and abnormally decreased free T3 levels after 8 weeks of lithium administration. These findings suggest that lithium may inhibit the peripheral conversion of free T4 to free T3 in some susceptible patients.

Adult↗
PubMed1995

A further prospective evaluation of an equation to predict daily lithium dose.

BACKGROUND: Recently, one prospective study confirmed the safety and accuracy of a lithium-dose prediction equation created by Zetin et al., but no definitive conclusion on the reliability of the equation has been established as yet. METHOD: The authors applied the Zetin et al. equation to 18 chronic male schizophrenic inpatients. Predicted doses to reach the serum lithium concentration of 0.4 mmol/L were calculated and prescribed in the form of lithium capsules. At Weeks 1 and 3 after treatment initiation, morning blood samples were collected about 12 hours after the last lithium dose for the measurement of serum lithium concentrations. RESULTS: None of the 18 patients achieved the desired concentration (0.4 mmol/L) exactly. The mean +/- SD of serum lithium concentrations at Week 1 was 1.01 +/- 0.29 mmol/L (range, 0.2-1.5) and at Week 3 was 0.94 +/- 0.35 mmol/L (range, 0.2-1.8). Lithium concentrations were lower than 0.4 mmol/L in only 1 patient and were higher than 0.4 mmol/L in the other 17 patients. The deviations from the unexpected value were significantly correlated with the renal function (blood urea nitrogen and serum creatinine levels) but not with the neuroleptic doses administered to the patients. Moreover, our patients were relatively older and weighed relatively less than the patients described in the previous prospective study. CONCLUSION: The Zetin et al. equation cannot always accurately predict a required lithium dose. Renal function data, even when they range within normal values, may be useful to improve the accuracy of the equation, particularly in patients who are older or weigh less than the norm.

Adult↗
PubMed1982

Ultrastructural changes of epithelium-connective tissue junction in experimental lingual tumors.

In this study, plaque-like lesions, epithelial hyperplasias, and papillary invasive carcinomas were produced in the tongues of hamsters by the application of DMBA combined with trauma for 16 weeks. The junction between the neoplastic epithelial cells and the connective tissue was studied ultrastructurally. In plaque-like lesions, the basal lamina was partially decreased in both thickness and density or partially discontinuous. In epithelial hyperplasias, cytoplasmic projections were observed in the portion of the basal cell near the intercellular space, and the basal lamina was absent around these cytoplasmic projections. In papillary invasive carcinomas, however, numerous cytoplasmic projections extended from various portions of the basal surface of the basal cells into the underlying connective tissue. The basal lamina was also absent around these projections. In epithelial hyperplasias and papillary invasive carcinomas, some of the cytoplasmic projections appeared almost empty, some contained a small number of tonofilaments and ribosomes, and others were filled with a large number of ribosomes but did not contain the tonofilaments. The collagen fibrils were markedly reduced in number in the area around cytoplasmic projections. The cytoplasm of some fibroblasts in that area contained many intracellular collagen fibrils.

9,10-Dimethyl-1,2-benzanthracene↗