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Biomedical subjects

Y Ohtsuka

Publications and source records attributed to Y Ohtsuka.

At least 217 records · Page 12Linked to original sources
PubMed1989

Impairment of glutathione metabolism in erythrocytes from patients with diabetes mellitus.

The metabolism of glutathione and activities of its related enzymes were studied in erythrocytes from patients with non-insulin-dependent diabetes mellitus (NIDDM). A decrease in the levels of the reduced form of glutathione and an increase in the levels of glutathione disulfide were found in erythrocytes of diabetics. To elucidate these changes in the levels of glutathione, synthetic and degradative processes were studied. The activity of gamma-glutamylcysteine synthetase was significantly lower in diabetics than in normal controls. The activity of glutathione synthetase of each group was the same. The rate of outward transport of glutathione disulfide in diabetics decreased to approximately 70% of that of normal controls. The activity of glutathione reductase decreased in diabetics. These data suggest that the decrease in the levels of reduced form of glutathione in erythrocytes of diabetics is brought about by impaired glutathione synthesis and that the increase in the levels of glutathione disulfide is brought about by the decreased transport activity of glutathione disulfide through the erythrocyte membrane together with a decrease in the activity of glutathione reductase. These data also suggest that the impairment of glutathione metabolism weakens the defense mechanism against oxidative stress in erythrocytes of diabetics.

Adult↗
PubMed1989

Fundamental study on latex reagents for agglutination tests.

Competitive adsorption of Fab and Fc fragments on to particles revealed that the main driving forces for the adsorption of Fab and Fc fragments are ionic and hydrophobic forces, respectively. Latex particles were sensitized with antihuman C-reactive protein-antibody under a condition where ionic binding force was suppressed, and hence antibody was supposed to attach to the particles predominantly at the Fc site. The resulting latex indicated a high efficiency for the determination of C-reactive protein. Among the latexes used, a partially hydrolysed styrene-acrylamide copolymer latex was the best with respect to test efficiency and storage stability.

Adsorption↗
PubMed1989

Platelet aggregation induced by latex particles. I. Effects of size, surface potential and hydrophobicity of particles.

Latex particles induced platelet aggregation associated with the release of ATP from the platelets. The smaller the diameter of particles having the same surface structure, the greater numbers or greater total surface area of particles were required for both reactions. The higher hydrophobic and higher negatively charged particles, having a diameter of about 0.3 micron, induced platelet aggregation most easily. Hydrophilic particles without high negative surface potential activated platelets only a little. Particle-induced platelet aggregation is not only caused by colloidal electronic force and hydrophobic interaction between platelets and latex particles but also by factors concerning cell activation.

Adenosine Triphosphate↗
PubMed1989

Long-term results of spinal instrumentation surgery for scoliosis five years or more after surgery, in patients over twenty-three years of age.

From 1967 to 1981, 311 scoliotic patients treated at Chiba University, with a minimum follow-up of 5 years and aged more than 23 years, were selected for this study. Seventy-two were males and 239 were females, whose age at operation ranged from 9 to 44 years, with an average of 16.5 years. The operative procedures were one-stage Harrington procedure in 179 cases, staged procedure in 108 cases, anterior procedure in 20 cases, and combined anteroposterior fusion in four cases. Including 198 patients examined physically, a total of 263 patients (54 males and 209 females) have responded to a questionnaire or were interviewed by telephone. In general, 85% of the patients were satisfied with the result of the operation for the control of spinal deformity, improvement of the cosmesis, and increase in physical and social activity.

Activities of Daily Living↗
PubMed1989

Clinical course and prognosis of childhood epilepsy.

Remarkable progress has been accomplished in epileptology in recent years. The remission rate in childhood epilepsy has been improved by the introduction of new technologies and better diagnostic as well as therapeutic methods. Investigation of prognosis is an important field of epileptology, because prognostic improvement reflects its overall progress. A long-term follow-up study of childhood epilepsy was undertaken in the Okayama University Hospital. Ten to 15 years of follow-up was possible in 730 of 1,295 patients who were first diagnosed at ages below 15 years, from 1968 to 1971. The 3-year remission rate amounted to 82.0% and 5-year remission was obtained in 79.1%. These high rates of remission indicate the favorable prognosis of childhood epilepsy. On the other hand, cases of intractable epilepsy also amounted to a considerable number. Intractable epilepsy consisted mainly of age-dependent epileptic encephalopathy (Ohtahara's syndrome, West syndrome and Lennox-Gastaut syndrome) and severe myoclonic epilepsy in infancy. Development of effective therapy for these intractable epileptic syndromes will be an important subject of future studies.

Adolescent↗
PubMed1989

[Hyperamylasemia in acute exacerbation in patients with chronic respiratory failure].

Serum amylase level was examined in 129 cases (225 episodes) of chronic respiratory failure at acute exacerbation, and in 59 cases (62 episodes) of pneumonia without respiratory failure as a control. Cases accompanying diseases, such as acute pancreatitis, parotiditis, ileus, and renal dysfunction, which were expected to develop hyperamylasemia were excluded. The 225 episodes were divided according to the cause of acute exacerbation into 4 groups: pneumonia, bronchitis, right heart failure without infection, and others (e.g. hemoptysis). Hyperamylasemia (greater than 400 S-U) was observed in groups of pneumonia (15/40 = 35.5%) and of bronchitis (12/95 = 12.6%) respectively, but not in those of right heart failure without infection (0/73 = 0%) and others (0/17 = 0%). As a result, hyperamylasemia was found only under conditions of inflammation of lung parenchyma and bronchi with acute exacerbation of respiratory failure. On the other hand no hyperamylasemia was observed in 62 episodes of only pneumonia without respiratory failure. It was concluded that both respiratory tract infection and acute respiratory failure are necessary factors for development of hyperamylasemia originating from lung or bronchi.

Aged↗
PubMed1989

[Photoelastic stress analysis at the metal-enamel junction of the anterior adhesive bridge on non-prepared teeth in eccentric jaw position].

To study the stress involved at the metal-enamel junction of an adhesive bridge during the eccentric movement of the mandible, the author calculated the values of principal stress and maximum shearing stress, and determined the stress distribution at the adhesive surface which exists between retainer and enamel, for which an unprepared canine and a centaral incisor, using a three-dimensional photoelastic experiment. Based on the assumed eccentric movement of the mandible, three models with loading at different parts of the adhesive bridge were used for the experiment: Model 1 with loading only on the central incisor, Model 2 with loading on the pontic of the lateral incisor and Model 3 with loading only on the canine. The results were as follows. (1) Models 1 and 3 showed stress concentration directly under the loading point, where the compressive stress was 610 kgf/cm2 in Model 1 and 610 kgf/cm2 in Model 3. (2) Model 1 showed distribution of stress of 30-80 kgf/cm2 at the metal-enamel junction of the canine, while in Model 3 the stress of 80-150 kgf/cm2 was distributed at the metal-enamel junction of the central incisor. Loading only on the canine produced higher levels and broader distribution of stress than loading only on the central incisor. (3) Model 2 showed distribution of stress of about 60 kgf/cm2 at the metal-enamel junction of the central incisor and canine. Extremely intense stress, 250 kgf/cm2, was noted in the canine slice contiguous to the pontic. Stress as high as 70 kgf/cm2 was also observed in the central incisor slice contiguous to the pontic. (4) The maximum shearing stress values were 305 kgf/cm2 in Model 1 and 325 kgf/cm2 in Model 3 at the sites directly under the loading point, showing similarly high levels. (5) A comparative investigation of the maximum shearing stress appearing at the metal-enamel junction among the models showed that the distributed maximum shearing stress in Model 3 was about twice that in Model 1. (6) Model 2 had the maximum shearing stress, which was located toward the pontic in the canine, with an intensity closed to the shearing strength of currently available adhesive resin cement, suggesting a high risk of desquamation at this site.

Dental Alloys↗
PubMed1989

[Objective assessment of senile changes in visual function by visually evoked cortical potentials].

The P100 peak latency of pattern visually evoked cortical potentials (P-VECP) was found to increase and amplitude decrease in the elderly depending on stimulus conditions. Using either of these as a criterion, changes of visual function with aging were quantitatively assessed both in humans and animals. Contrast threshold was found to increase at higher spatial frequency ranges and the luminance threshold increased more than 0.8 log unit. Also, the contrast threshold increased due to a smaller pupillary area and there was progressive decrease of the temporal frequency curves with age for lower frequency ranges of less than 10 rev/sec. In addition, a sensitivity decrease for the upper visual field was detected plus blue-yellow defects and a decrease in the amplitude of accommodation. In order to exclude the effect of senile changes of the crystalline lens, the luminance threshold, the accommodation power and color sense were investigated in pseudo-phakic eyes with a posterior chamber lens. No significant differences were found between phakic and pseudo-phakic eyes. Accordingly, it was suggested that reduced transparency and yellowish changes of the crystalline lens do not essentially contribute to the loss of function in the elderly found in the present study, but the neuronal pathway was responsible. As a clinical model of senescence, cases of juvenile parkinsonism were investigated, during L-dopa treatment and after ceasing it. The deficiency of the neural-transmitter of the higher visual pathway was indicated in the elderly, also. Animal experiments on neuronal dysfunction in rats and mice suggested no aging effects in ERGs, whereas VECP peak latency for higher temporal frequencies increased with age. The assumption that the elderly changes occur at the neuronal level was supported by a loss of optic nerve fibers in mice with age. The numbers of optic nerve fibers measured were 48,115, 50,875 in the 3-month-old and 6-month-old groups, respectively, and decreased to 43,175 in the 30-month-old group. Though our results indicated the senescence of visual function at the neuronal level, it was not as much as shown by other sensory organs. It was therefore presumed that there might be a certain feed-back system from the brain to the retina.

Adolescent↗
PubMed1988

Oxidative stresses induced the cystine transport activity in human erythrocytes.

Cystine was transported into human erythrocytes in the presence of tertiary-butyl hydroperoxide (t-BH) or 1-chloro-2,4-dinitrobenzene (CDNB). The transport rate of cystine was dependent on the extracellular concentration of t-BH or CDNB, and on the incubation time. According to Dowex-1 column chromatography, the transported cystine was incorporated into fractions of glutathione disulfide (GSSG) and glutathione-S (GSH-S) conjugate. The transport of cystine was competitively inhibited by DL-homocystine and alanine. The inhibition rates by DL-homocystine and alanine were 75% and 68%, with similar Ki values of 0.7 mM and 0.6 mM, respectively. It is suggested that cystine transport is induced for glutathione synthesis when human erythrocytes are exposed to oxidative stresses. This transport system of cystine may serve as an emergency function in human erythrocytes.

Biological Transport↗
PubMed1988

School screening for scoliosis by the Chiba University Medical School screening program. Results of 1.24 million students over an 8-year period.

The screening program for scoliosis started by Chiba University in 1979 consists of using moiré topography, low-dose roentgenography and a final ordinary x-ray examination. The number of children screened through this Chiba University Medical School (CUMS) screening program to 1986 amounted to 1,246,798. The incidence of scoliosis of more than 15 degrees increased linearly according to age from the fifth grade primary school children (0.07% in boys, 0.44% in girls) to the second grade junior high school students (0.25% in boys, 1.77% in girls). The female predominance of scoliosis cases with curvatures of more than 20 degrees detected during the total period was 10:1 and this female predominance was the same for primary school children and junior high school students. According to a study of the incidence of scoliosis by districts, (areas were divided according to population density and urbanization) there were no significant differences in the fifth grade primary school children between the sparsely and densely populated areas. In the cases of children beyond the fifth grade primary school level, however, the incidence in the densely populated areas were significantly higher than those in the sparsely populated districts. The incidence of scoliosis of more than 20 degrees decreased significantly every year among junior high school students, because they were screened periodically in school and the scoliotic students who had already been detected were left out of the next screening. This study establishes that screening for scoliosis by the CUMS screening program is cost-effective with a low risk of radiation hazards.

Adolescent↗
PubMed1988

Generation of intracellular active oxygens in mouse FM3A cells by 3-hydroxyamino-1-methyl-5H-pyrido[4,3-b]indole, the activated Trp-P-2.

Mouse FM3A cells in culture were treated with a reactive metabolite of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 3-hydroxyamino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2-(NHOH]. When the treated cells, which were judged as viable on the basis of trypan-blue exclusion, were subjected to nitroblue tetrazolium staining, formazan was formed inside the cells, a fact suggesting the intracellular presence of superoxide. No formazan formation was detected on treatment of the cells with Trp-P-2. Single-strand breaks in the cellular DNA took place during this treatment with Trp-P-2(NHOH). Since Trp-P-2(NHOH) in solution generates superoxide anion accompanying its oxidative degradation, we conclude that the Trp-P-2(NHOH) treatment produces intracellular active oxygens that can damage DNA.

Animals↗
PubMed1988

Rational treatment of refractory epilepsy in childhood.

A multifaceted study on childhood refractory epilepsy disclosed an insufficient classification of epilepsies and epileptic seizures, and inappropriate polypharmacy as the most important factors preventing appropriate therapy. By means of an adjustment of AEDs based on the accurate classification of epilepsies and epileptic seizures, the number of AEDs could be reduced in 37.5% and monotherapy was successful in 13.8% of refractory cases. Most of the latter were those of partial epilepsy and generalized epilepsy with the monoseizure type. The exacerbation of seizures due to AEDs was also mentioned as one of the important side effects of AEDs.

Adolescent↗
PubMed1988

Nonconvulsive status epilepticus with continuous diffuse spike-and-wave discharges during sleep in childhood.

On three epileptic conditions with common characteristics of almost continuous diffuse spike-and-wave discharges during sleep in EEG, clinical and electroencephalographic studies were undertaken to elucidate their pathophysiologies and interrelationships; namely on five cases of epilepsy with electrical status epilepticus during slow sleep (ESES), seven cases of a peculiar type of nonconvulsive status epilepticus in childhood (PNSE) and three cases of atypical benign partial epilepsy (ABPE). The dominant seizure types were absences and/or GTC in ESES, whereas they were focal motor seizures in PNSE and ABPE with more focalized epileptic discharges on EEGs than those in ESES. All the three conditions showed both features of generalized and partial epilepsies, although the former features were more prominent in ESES and the latter in PNSE and ABPE.

Adolescent↗
PubMed1988

Hormonal regulation of glycogen synthase and phosphorylase activities in human polymorphonuclear leukocytes.

Hormonal regulation of glycogen synthase and phosphorylase activities were studied in human polymorphonuclear leukocytes. Polymorphonuclear leukocytes from normal subjects were incubated with glucose, insulin, D,L-isoproterenol and L-thyroxine, either independently or in different combinations, and changes of the enzyme activity ratios of glycogen synthase (active form (I)/total activity (T)) and glycogen phosphorylase (active form (a)/total activity (T)) were assessed. Neither glucose nor insulin changed the glycogen synthase activity ratio. However, the proportion of the active form (I) of glycogen synthase was increased by the simultaneous addition of glucose and insulin to the incubation mixture, but D,L-isoproterenol or L-thyroxine diminished this effect and caused a decrease in the proportion of the active form of glycogen synthase. Insulin had no effect on the glycogen phosphorylase activity ratio. Glucose decreased the proportion of phosphorylase in the a form. The simultaneous addition of glucose and insulin caused no further changes, whereas in the presence of D,L-isoproterenol or L-thyroxine, this glucose effect was abolished and the proportion of phosphorylase a increased. These results show that both thyroid hormone and a beta-agonist alter glycogen metabolism to reduce glycogen storage in polymorphonuclear leukocytes.

Drug Interactions↗