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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 613 records · Page 34Linked to original sources
PubMed1992

Myelin gangliosides of human peripheral nervous system: an enrichment of GM1 in the motor nerve myelin isolated from cauda equina.

Myelins of the PNS were isolated from human motor and sensory nerves of cauda equina, and their ganglioside compositions were compared. The predominant ganglioside in the human PNS myelins, both from motor and sensory nerves, was LM1 (sialosylneolactotetraosylceramide). Sialosyl-nLc6Cer and disialosyl-nLc4Cer, GD3, GM3, and GD1b were detected as common components of the two nerve myelins. Furthermore, it was revealed that the motor nerve myelin contained GM1 (about 15% of total gangliosides), whereas sensory nerve myelin contained only a trace amount of GM1 (less than 5%), by TLC analyses together with TLC immunostaining using anti-GM1 antibody. As for the disialoganglioside fraction, the content of GD1a, as well as that of GM1, differed in motor and sensory nerves. Thus, the different contents of the ganglioseries gangliosides in human motor and sensory nerve myelins were demonstrated.

Cauda Equina↗
PubMed1992

Ecological structure and incidence rates of schizophrenia in Nagasaki City.

The purpose of this study was to investigate the relationship between incidence rates of schizophrenia and residential features in Nagasaki City, Japan. Social features of residents in 259 areas in the Nagasaki City ecological structure were determined using the results of the 1980 national census. Six residential factors--employment status, occupational and academic career, household status, length of residence, housing tenure and young male predominance--were selected as factors that clearly reflect residential differentiation of residents. Contrary to the findings of many other studies conducted in Western cities, no statistically significant differences were observed, although it seemed that incidence rates were comparatively higher in the lower social classes. These results possibly reflect differences in cultural and social values and structures.

Adult↗
PubMed1992

Binding of mutagenic pyrolyzates to fractions of intestinal bacterial cells.

The binding of mutagenic pyrolyzates to cell fractions from some gram-negative intestinal bacteria and to thermally treated bacterial cells was investigated. 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) were effectively bound by several of the bacterial cells. The cell wall skeletons of all bacteria effectively bound Trp-P-1 and Trp-P-2. Their cytoplasmic fractions retained Trp-P-1 and Trp-P-2, but to a lesser extent than the cell wall skeletons. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) was not found in their cytoplasmic fractions. These cell wall skeletons also bound 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), 2-amino-5-phenylpyridine (Phe-P-1), IQ, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQX). The amount of each mutagen bound differed with the type of mutagen and the bacterial strain used. The outer membrane of Escherichia coli IFO 14249 showed binding of about 123.7 micrograms/mg of Trp-P-2, and its cytoplasmic membrane bound 57.14 micrograms/mg. Trp-P-2 bound to the bacterial cells was extracted with ammonia (5%), methanol, and ethanol but not with water.

Bacteroides fragilis↗
PubMed1992

Intestinal anisakiasis: US in diagnosis.

Eighteen consecutive patients with intestinal anisakiasis were studied with high-resolution ultrasound (US) and barium studies. US showed markedly thickened bowel loops associated with luminal narrowing, swelling of Kerckring folds, and decreased peristalsis. A small amount of ascitic fluid around the bowel loops was found, and cytologic examinations of the ascites revealed a dense infiltration of eosinophils. Barium studies demonstrated segmental mucosal edema of the small intestine: The most common site was the distal ileum, and the mean length of the edematous lesion was 19 cm. All patients underwent treatment of symptoms without laparotomy, and their symptoms disappeared by the eighth day after onset. Patients with acute abdominal symptoms should be asked about the intake of raw or undercooked fish. If the above US features are found, the diagnosis of intestinal anisakiasis must be seriously considered to avoid unnecessary surgical treatment.

Adult↗
PubMed1992

In vivo recording of electrical activity of canine tracheal smooth muscle.

Electrical activity of the tracheal smooth muscle was studied using extracellular bipolar electrodes in 37 decerebrate, paralyzed, and mechanically ventilated dogs. A spontaneous oscillatory potential that consisted of a slow sinusoidal wave of 0.57 +/- 0.13 (SD) Hz mean frequency but lacked a fast spike component was recorded from 15 dogs. Lung collapse accomplished by bilateral pneumothoraxes evoked or augmented the slow potentials that were associated with an increase in tracheal muscle contraction in 26 dogs. This suggests that the inputs from the airway mechanoreceptors reflexly activate the tracheal smooth muscle cells. Bilateral vagal transection abolished both the spontaneous and the reflexly evoked slow waves and provided relaxation of the tracheal smooth muscle. Electrical stimulation of the distal nerve with a train pulse (0.5 ms, 1-30 Hz) evoked slow-wave oscillatory potentials accompanied by a contraction of the tracheal smooth muscle in all the experimental animals. Our observations in this in vivo study confirm that the electrical activity of tracheal smooth muscle consists of slow oscillatory potentials and that tracheal contraction is at least partly coupled to the slow-wave activity of the smooth muscle.

Action Potentials↗
PubMed1992

Myocardial uptake of 111In monoclonal antimyosin Fab in detecting doxorubicin cardiotoxicity in rats. Morphological and hemodynamic findings.

BACKGROUND: The therapeutic value of doxorubicin (DOX) is limited by its cardiotoxicity, which is dose dependent. To improve the detection of such myocardial damage, this study was designed to determine whether the 111In antimyosin antibody Fab could serve as a marker for cardiotoxicity in treated versus control rats on the basis of comparative morphological and hemodynamic findings. METHODS AND RESULTS: DOX was administered by intravenous injection to rats at a dose of 3 mg.kg-1.week-1 for 5 weeks. Three weeks after the final injection, an intravenous dose of 111In antimyosin, 740 kBq (20 microCi), was administered, and tissue distribution of the radioisotope (percent kilogram dose per gram) was assessed in 48 hours. Myocardial uptake of radioactivity by both ventricles was more prominent in the DOX-treated rats than in control rats (p < 0.001). The heart-to-blood and heart-to-lung uptake ratios were markedly higher in the treated rats than in controls (p < 0.001). As the severity of the myocardial damage increased, there was a progressive increase in myocardial uptake. There was a strong correlation between the severity of myocardial damage and the ventricular end-diastolic pressure (r = 0.84 and r = 0.83 in the left and right ventricles, respectively). On microscopic immunoautoradiography of the DOX-treated heart, there was a specific immunolocalization of the radiotracer in the injured myocytes but no radioactivity in the control myocytes. CONCLUSIONS: 111In antimyosin antibody appears to be a useful immunoradiotracer in detecting cardiac damage induced by DOX administration and in assessing the severity of cardiotoxicity. These data reinforce the clinical observation that myocardial imaging using 111In antimyosin Fab is able to provide information to guide the course of patients receiving DOX treatment.

Animals↗
PubMed1992

31P-NMR study of skeletal muscle metabolism in patients with chronic respiratory impairment.

To evaluate the energy metabolism of peripheral skeletal muscle during exercise in patients with chronic respiratory impairment, the 31P-nuclear magnetic resonance (NMR) spectra of forearm muscle were investigated in nine patients and nine age-matched control subjects. We calculated the phosphocreatine (PCr) to PCr + inorganic phosphate (PI) ratio, the time constant of PCr recovery and the intracellular pH. The exercise consisted of repetitive hand grips against a 2-kg load every 3 s for 6 min (0.33 W). The patients showed a marked decrease in the PCr/(PCr + PI) ratio and pH in the muscle during exercise in contrast to the control subjects whose PCr/(PCr + PI) showed a minor decrease without any change in pH. The relationship between PCr utilization and pH demonstrated that anaerobic glycolysis switched on earlier in patients with chronic respiratory impairment. A split PI peak was observed in five of nine patients during exercise. The PCr/(PCr + PI) ratio during the last minute of exercise correlated significantly with the vital capacity (% predicted), with the FEV1/FVC, with the body weight, with the maximum strength of hand grip, and with the muscle mass. The results indicate impaired oxidative phosphorylation and the early activation of anaerobic glycolysis in the muscles of patients with chronic respiratory impairment. Several factors related to chronic respiratory impairment, such as disuse, malnutrition and dysoxia, would contribute to the metabolic changes observed in the muscles examined.

Aged↗
PubMed1992

Reperfusion after a two-hour period of pulmonary artery occlusion causes pulmonary necrosis.

The role of reperfusion injury in the progression to necrosis in pulmonary embolism was evaluated. To simulate this condition, we used a technique that enables occlusion and reopening of the pulmonary arterial branch supplying the right upper lobe in conscious rats. The rats were divided into five groups: the occlusion group (n = 12), in which the pulmonary artery (PA) branch was occluded without reperfusion; the reperfusion group (n = 12), in which the PA branch was reopened after a 2-h period of occlusion; and the reperfusion-SOD (n = 9), reperfusion-IM (n = 8), or reperfusion-IA-SOD (n = 6) groups, in which superoxide dismutase (SOD), indomethacin (IM), or inactivated SOD (IA-SOD), respectively, was administered during reperfusion. The lungs were removed 24 h after the PA occlusion, and histologic examination was performed. In the occlusion group, the alveolar structure of the right upper lobe was well preserved, and there was no erythrocyte or leukocyte accumulation. The only significant changes compared with the control lobe was the appearance of wavy internal elastic lamina of the PA and slight neutrophil adherence to the endothelial cells. In contrast, the right upper lobe of the reperfusion group disclosed numerous foci of hemorrhagic necrosis, with disrupted alveoli and leukocyte accumulation in all cases. With SOD treatment, the changes compatible with hemorrhagic necrosis were attenuated to the level of the control lobes. However, neither IM nor IA-SOD decreased these changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[MR imaging of cerebral lesions accompanying stroke in stroke-prone spontaneously hypertensive rats].

Cerebral lesions accompanying stroke in male stroke-prone spontaneously hypertensive rats (SHRSP, n = 10) were examined by both magnetic resonance imaging (MRI) and histological evaluation. T2-weighted MR images (T2-WI), taken 1-2 days after animals showed behavioral hyperactivity, indicated hyperintense regions in the occipital cortex, caudate putamen and/or thalamus. The areas of hyperintensity on T2-WI corresponded to neurodegenerative regions including edema, gliosis, and softening of the tissue. T1-weighted images (T1-WI) did not show any hyperintense regions. However T1-weighted images enhanced by the contrast media Gd-DTPA (Gd-T 1-WI) showed hyperintense spots within some of the hyperintense areas on T2-WI, which exhibited neurodegenerative regions such as thrombus, angionecrosis and hemorrhage in addition to the edematous formation. The hyperintense areas on Gd-T1-WI were smaller than those on T2-WI. In some animals, hypointense spots on T2-, T1- and Gd-T1-WI were found within the hyperintense areas, which corresponded to clots. Extensive histological examination did not reveal any additional cerebral degeneration which had not been detected on the MR images. These findings indicate that MRI is useful for detecting and differentiating various types of cerebrovascular disease in this model.

Aging↗
PubMed1992

[Concentration of trace elements in hair from children living in a Keshan disease district in China].

The hair from 9 children living in a Keshan disease prevalent district and from 10 children living in a Keshan disease non-prevalent district in China was analyzed. At the same time, the hair from 35 children of the same age residing in Tsukuba district in Japan was analyzed for comparison of the concentration of essential trace elements with that of children living in the Keshan disease prevalent district. Se concentration was determined by a fluorophotometric method and 16 other elements were analyzed by ICP emission spectrometry. Hg was analyzed by the heating evaporation method and by neutron activation analysis. The Se concentration in the hair of children living in the prevalent district was very low, being one-tenth that of the Japanese. The Ni concentration was particularly low in the prevalent district, and it determined to study more about the effects of Ni deficiency on health. In the prevalent district, Mg and Ca levels were low and those of Pb, Fe, Al, Ti were relatively high. Mn concentrations of both districts in China were very high when compared to the Japanese. The results of this study showed that the low Se concentration in Keshan disease is in agreement with previously reported data. Ecological factors, including nutrition were considered to be important in the etiology of this disease.

Adolescent↗
PubMed1992

Continuous chitosan hydrolyzate production by immobilized chitosanolytic enzyme from Enterobacter sp. G-1.

Chitosanolytic enzymes from Enterobacter sp. G-1 were immobilized on various carriers to continuously hydrolyze chitosan. Four different carriers were tested: FE-3901 (strong basic anion exchange resin, ionic binding), glutaraldehyde-treated FE-4612 (weak basic anion exchange resin, cross-linking), Chitopearl (chitosan beads), and alginate calcium. Glutaraldehyde-treated FE-4612 and Chitopearl immobilized more protein than the others. The enzyme immobilized on FE-3901 had the greatest activity. The activity of enzyme immobilized on FE-3901 decreased rapidly when exposed to a continuous flow of 1% chitosan. The enzyme immobilized with Chitopearl retained more than 50% of its original activity after 17 days, and the activity was fully restored by re-immobilization.

Anion Exchange Resins↗
PubMed1992

Prediction of the outcome of postoperative hypocalcemia in Graves' disease.

Symptomatic hypocalcemia sometimes follows subtotal thyroidectomy for Graves' disease. Irreversible damage to the parathyroids contributes to permanent hypocalcemia and the mechanism for a transient hypocalcemia is thought to be different from that of a permanent one. However, sensitive assays for parathyroid hormones (PTH), which had recently become available, revealed that levels of PTH decrease in patients with transient hypocalcemia. In order to differentiate a prolonged hypocalcemia from a transient one, calcium and inorganic phosphate concentrations in serum as well as in urine, and whole molecule-PTH levels were determined in 18 Graves' disease patients with postoperative hypocalcemia just after the initial symptoms for hypocalcemia appeared. In 13 patients, medication was withdrawn within one month since serum calcium levels had returned to normal (transient hypocalcemia). In five other patients, medication was required for six months or more to maintain normocalcemia (prolonged hypocalcemia). The same parameters were determined after surgery in eight Graves' disease patients without hypocalcemia. Urinary inorganic phosphate concentrations in patients with prolonged hypocalcemia (0.02 +/- 0.01 mmol/mmol Cr) were significantly lower (P less than 0.01) than those in patients with transient hypocalcemia (1.59 +/- 1.59 mmol/mmol Cr) or those in control patients (1.27 +/- 0.70 mmol/mmol Cr). Preoperative concentrations of calcium and inorganic phosphate in serum and urine, and serum alkaline-phosphatase activities were also determined. However, there were no significant differences in these parameters between patients with prolonged and those with transient hypocalcemia. It is concluded that prolonged hypocalcemia is discriminated from the transient type by determining the urinary inorganic phosphate at the time of appearance of the initial symptoms for hypocalcemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Two cases of hypothyroidism associated with alpha-interferon therapy.

Alpha-interferon was used for anti-cancer or anti-viral therapy in two patients with preexisting autoimmune thyroid disease and in seven patients with chronic viral hepatitis who had no history of thyroid dysfunction. Primary hypothyroidism developed in the two patients who had a history of autoimmune thyroid disease, while no changes in thyroid function were observed in the other seven patients. Modulation of the immune system by alpha-interferon may have been responsible for the development of hypothyroidism in these two patients. Therefore, autoantibodies to the thyroid and the thyroid function should be assessed in patients undergoing alpha-interferon therapy.

Adenocarcinoma↗
PubMed1992

Expiratory activity of the inspiratory muscles during cough.

To investigate the neural mechanism of the expiratory activity of the inspiratory muscles during a cough, EMG of the respiratory muscles were recorded in anesthetized and tracheostomized dogs. A laparoscope was used to minimize injury to the abdominal muscles for implantation of the electrodes into the costal diaphragm. During the expulsive phase of a cough, the diaphragm was active in 7 of 12 dogs and the external intercostal muscle was active in 3 of 6 dogs. During a cough, the expiratory activity of the diaphragm, after the termination of its inspiratory activity, started at 52.9 +/- 24.6 ms, and that of external intercostal muscle started at 51.1 +/- 20.5 ms. The expiratory activity of the internal intercostal muscle and of the transversus abdominis started at 34.3 +/- 13.0 and 27.8 +/- 15.2 ms, respectively. The onset of expiratory activity of the inspiratory muscles is significantly later than that of expiratory muscles. Continuous activity in the expiratory muscles evoked by airway occlusion, i.e., Hering-Breuer reflex, was suppressed during the inspiratory phase of a cough, but not suppressed during the expulsive phase even when the expiratory activity of the diaphragm was observed. We concluded that the expiratory activity of inspiratory muscles is controlled independently of both expiratory activity of the expiratory muscles and inspiratory activity of the inspiratory muscles.

Animals↗
PubMed1992

Development of collagen fibers and vasculature of the fetal TMJ.

Using 12 human fetuses, histological development and changes in connective fiber structure and fine vascular patterns have been investigated in various fetal gestational stages by light and scanning electron microscopy. The main arterial supply of the articular disc was from the bilaminar region and pterygoideus lateralis muscle. The vascular network on the disc surface was related with fluid secretion. When the bilaminar region was compressed, it caused ischemia and fibrosis as the main pathological changes in TMJ derangement. A decrease in fluid from blood vessels might occur in TMJ degeneration. Collagen fibers in the disc passed mainly anteroposteriorly. In the anterior and posterior bands, muscular tendon fibers came from the pterygoideus lateralis muscle and superior stratum of the bilaminar region. In the posterior band three-dimensional structures of collagen fibers suitable for load bearing were observed. The compass network and process on the disc showed the normal structure that is formed gradually and has functions including dispersion, pressure bearing, friction-proofing and storage of the synovial fluid. Attachments of the disc were suitable for disc function. Large elastic fibers in the posterolateral part of the superior stratum of the bilaminar region may be antagonistic to the upper head of the pterygoideus lateralis muscle fibers passing medioanteriorly, indicating that this antagonism is available for disc function.

Collagen↗
PubMed1992

Machine perfusion of isolated kidney at 37 degrees C using pyridoxalated hemoglobin-polyoxyethylene (PHP) solution, UW solution and its combination.

To preserve isolated kidney normothermically, PHP containing UW components were evaluated as perfusates. Kidneys were flushed out by Lactate Ringer solution immediately after isolation from mongrel dogs, and then connected to the perfusion circuit which consists of a preservation box, a reservoir of perfusate, a membrane oxygenator and a drive unit. PHP containing 140 mEq/l of Na+ and 4 mEq/l of K+ (PHP(E)), UW solution (UW) and UW components added PHP(E) were prepared and adjusted at pH 7.4 prior to use. Temperature and perfusion pressure were controlled at 37 degrees C and 100 mmHg, respectively. During 12 hour perfusion, remarkable changes in pH were seen in UW group and PHP group while higher oxygen consumption was noted in PHP(E)+UW group than that in PHP(E) group. The histological findings showed moderate damages of tubular epithelial cells and maintaining normal glomerular structure in PHP(E)+UW while severe damage of both tubulus in UW group were seen. There was no edematous degeneration in both UW and PHP(E)+UW groups, however, it was seen in PHP(E) alone. It was suggested that components of UW solution have positive effect on normothermic machine perfusion with PHP(E) solution.

Adenosine↗