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Biomedical subjects

K Okamura

Publications and source records attributed to K Okamura.

At least 361 records · Page 20Linked to original sources
PubMed1989

Detection of bisected biantennary form in the asparagine-linked oligosaccharides of fibronectin isolated from human term amniotic fluid.

Fibronectin purified from human term amniotic fluid contains 10 asparagine-linked sugar chains in one molecule. The sugar chains were quantitatively liberated as radioactive oligosaccharides from the polypeptide moiety by hydrazinolysis followed by N-acetylation and NaB3H4 reduction and fractionated by anion-exchange column chromatography and serial lectin affinity chromatography. The structures of these sugar chains were determined by sequential exoglycosidase digestion in combination with methylation analysis. The results indicated that they are a mixture of bisected and non-bisected bi- and triantennary complex-type sugar chains with and without a fucose on the proximal N-acetylglucosamine residue and with Gal beta 1----4GlcNAc beta 1----, GlcNAc beta 1----, Neu5Ac alpha 2----3Gal beta 1----4GlcNAc beta 1----, and Neu5Ac alpha 2----6Gal beta 1----4GlcNAc beta 1---- groups in their outer chain moieties.

Amniotic Fluid↗
PubMed1989

Molecular cloning and nucleotide sequence of the gramicidin S synthetase 1 gene.

The entire gene for gramicidin S synthetase 1 (GS 1) was cloned into the plasmid vector pUC18, and the nucleotide sequences of the GS 1 gene and its flanking region were determined. The full-length clone was 4,539 base pairs long and had an open reading frame of 3,294 nucleotides coding for 1,098 amino acids. The calculated molecular weight of 123,474 agreed with the apparent molecular weight of 120,000 found in SDS-PAGE of GS 1 from B. brevis. The nucleotide sequence of GS 1 gene was highly homologous to that of tyrocidine synthetase 1. The overall similarity between the deduced amino acid sequences of the two genes was 57.5%. The gene product of clone GS309 was easily purified to an essentially homogeneous state by ammonium sulfate fractionation followed by DEAE-Sepharose CL-6B, Ultrogel AcA-34, and second DEAE-Sepharose CL-6B column chromatography. The purified protein catalyzed the D-phenylalanine-dependent ATP-32PPi exchange reaction which is specific for GS 1 activity, and the specific activity of the purified product was nearly the same as the purified GS 1 from B. brevis. The product also showed a weak phenylalanine racemase activity.

Amino Acid Isomerases↗
PubMed1989

Catecholamine content changes in brain regions of spontaneously hypertensive rats under immobilization stress.

We compared the effect of immobilization stress on noradrenaline (NA) and 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) content in two brain regions--diencephalon and pons-medulla oblongata--in young and adult spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). In SHR, NA content decreased with time after the onset of the stress, whereas levels of its metabolite MHPG increased. In WKY, NA and MHPG showed no change. The MHPG/NA ratio in both regions increased relative to the duration of the stress in SHR, whereas it remained almost constant in WKY. The rate of increase in the ratio was much higher in the diencephalon of adult (12-week-old) than of young (4-week-old) SHR. In SHR, NA turnover in the brain is readily affected by environmental stress, and these changes in the noradrenergic system may induce or sustain hypertension.

Aging↗
PubMed1989

A sensitive thyroid stimulating hormone assay for screening of thyroid functional disorder in elderly Japanese.

The use of a screening test for thyroid functional disorder by sensitive thyroid stimulating hormone assay in the elderly was investigated. The basal thyroid stimulating hormone levels predicted the response of thyroid stimulating hormone to thyrotropin releasing hormone; it was suppressed in 99 (99.0%) of 100 hyperthyroid patients. Therefore, not only primary hypothyroidism but also hyperthyroidism can be excluded when the serum thyroid stimulating hormone levels are normal. An epidemiological study was then performed on 2,421 (76.7%) of the Japanese general population aged 40 or over recruited from the residents in Hisayama town and also in 122 residents between 20 and 40 years of age. Additional free T4 measurement was necessary in about 10% of the residents with abnormal TSH levels to confirm the diagnosis of hyperthyroidism or distinguish latent from overt hypothyroidism. There was a significant correlation between age and serum thyroid stimulating hormone levels after logarithmic conversion (r = 0.1533, P less than .001). The prevalence of thyroid dysfunction found in 1,026 males and in 1,395 females aged 40 or over was, respectively: hyperthyroidism, less than 0.1% and 0.2%, latent (subclinical) hypothyroidism, 3.2% and 5.5%, and overt hypothyroidism, 0.4% and 0.7%. We conclude that the screening with this sensitive thyroid stimulating hormone assay and additional free T4 measurement is useful for detection of patients with thyroid functional disorder.

Adult↗
PubMed1989

[A case of cryptococcal meningitis successfully treated with miconazole and CSF drainage].

Cryptococcal meningitis is the most frequent fungal infection of the central nervous system, known readily to complicate with immuno-compromised patients. There are only a few cases of primary infection in healthy non-immuno-compromised patients. Amphotericin-B (AMPH-B) and 5-Fluorocytosine (5-FC) are effective agents against Cryptococcal meningitis, although, their toxicity and drug resistance are limiting factors. However, in recent years Miconazole has been widely used against fungal infections and it's effectiveness has been reported. This is a 68 y.o. male who was admitted to Toyohashi Municipal Hospital on March 15, 1987 because of headache, vomiting, diplopia and gait disturbance. Continuous lumbar drainage was performed since lumbar puncture revealed surprisingly high cerebrospinal fluid (CSF) pressure and presence of many Cryptococcus neoformans, i.v. AMPH-B and p.o. 5-FC was also administrated. A 7 day course of i.v. AMPH-B and p.o. 5-FC showed no improvement with side effects of macrohematuria and anorexia. Then Miconazole was administrated i.v. and intrathecal (i.t.). The clinical signs and CSF laboratory data improved after a 90 day course of Miconazole therapy and the patient was discharged on August 24. But the patient was readmitted from March 10 to April 30, 1988, because of a slight increase of C. neoformans in CSF (17/mm3) and improved by i.v. and i.t. Miconazole. The total Miconazole dosage was 90.6 g (i.t.: 505 mg) at the first admission and 36 g (i.t.: 50 mg) at the second admission, but no side effect was seen. The reduction of elevated CSF pressure with continuous CSF drainage was also important for the treatment of such cases with increased intracranial pressure.

Aged↗
PubMed1989

Reevaluation of nonstress test by umbilical venous blood profile using cordocentesis.

Fetal blood sampling by cordocentesis was performed in 85 cases of fetuses with either nonimmune hydrops fetalis, anomalies, intrauterine growth retardation, maternal immunological disorders, Rh incompatibility, hydronephrosis, polyhydramnios, maternal preeclampsia or fetal tumor. Fetal heart rate monitoring was also recorded before cordocentesis. We evaluated the usefulness of the nonstress test (NST) with regard to fetal hematologic gas profiles including pH, pO2 and pCO2. When the acceleration was classified into reactive and nonreactive group, pH and pO2 were significantly higher in the reactive group than in the nonreactive group. pCO2 was significantly lower in the former than the latter. However, the sensitivity and specificity of the reactive NST predicting fetal umbilical venous pO2 over 20 mm Hg was 79.7 and 68.7%, respectively. The false-positive rate of nonreactive NST predicting hypoxemia below 20 mm Hg pO2 was 44%. As a consequence, we cannot always rely on the NST, and should perform fetal blood sampling to assess fetal condition for further management.

Carbon Dioxide↗
PubMed1989

Hypotensive effects of nifedipine in patients with primary hyperparathyroidism: case reports.

Nifedipine was administered orally to 2 patients with primary hyperparathyroidism before and after parathyroidectomy. The operation lowered serum calcium concentration and parathyroid hormone but did not alter plasma renin activity, plasma aldosterone concentration, and serum magnesium. The hypotensive effects of nifedipine were markedly enhanced with the decrease in serum calcium concentration following parathyroidectomy. Thus, the level of serum calcium concentration may modulate the hypotensive effect of nifedipine in humans.

Aged↗
PubMed1989

Basis for the assay of myogenic cell growth in vitro using creatine kinase activity as an index, with special reference to measurement of power ratio of transferrins in growth promotion.

In order to establish an assay for the in vitro growth of myogenic cells, we investigated whether creatine kinase (CK) activity can be used as an index for the estimation of growth. The content of CK activity in a primary myogenic cell culture, almost all of which originated from myotubes, was shown to be linearly proportional to the content of proteins in the myotubes and increased concomitantly with myotube growth. CK activity can be easily and accurately assayed and used for routine assay of the cell growth. As an example of the application of CK activity for the bioassay of growth promoting substances, the relative potency (Pr) of turkey transferrin (Tf) to chick Tf in the promotion of chick myogenic cells was examined with a parallel line assay. The calculation limited that Pr = 0.363, ranging from 0.356 to 0.370, at 95% safety. The results demonstrated the usefulness of CK activity for estimating cell growth, as well as the value of a statistical method for the assay of a growth factor in vitro.

Analysis of Variance↗
PubMed1989

Alteration of FHR pattern and cerebral metabolic rate of glucose of the fetus measured by positron emission tomography during progress of acidemia. The significance of overshoot acceleration in FHR.

In order to investigate the significance of overshoot acceleration in FHR with acidosis induced by serial cord compression, cerebral glucose metabolic rate (CMRglc) was measured in four chronically instrumented fetuses before cord compression and immediately after appearance of the overshoot acceleration in FHR. The investigation of CMRglc was carried out using positron emission tomography to assess accumulation of cyclotron-produced F18-FDG in the fetal brain. CMRglc in the fetal brain in the nonacidemic condition was 1.73 mg/100 g/min. In acidemia, with fetal arterial pH near 7.15 in which FHR showed the characteristic pattern with overshoot acceleration, CMRglc was significantly decreased to 0.73 mg/100 g/min. We concluded that, to avoid neuronal damage, it is necessary to intervene when the fetal condition deteriorates to the extent that overshoot acceleration in FHR occurs.

Acidosis↗
PubMed1989

A case of normotensive primary aldosteronism with hypopituitarism, epilepsy, and medullary sponge kidney.

A 55-year-old man with normotensive primary aldosteronism, hypopituitarism, epilepsy, and medullary sponge kidney is reported. Seventeen years before admission, he had been noted to have hypokalemia associated with high potassium clearance, suppressed plasma renin activity, metabolic alkalosis, and normal blood pressure as well as low urinary excretion of 17-hydroxycorticosteroids. He kept normotensive in spite of hyperaldosteronism until nine months after the initiation of replacement therapy with glucocorticoid and thyroxine for hypopituitarism, when he became hypertensive. Hypopituitarism seemed to play a role in keeping a normal blood pressure despite long-standing hyperaldosteronism.

Adrenal Glands↗
PubMed1989

Gastric lesions induced by kainic acid injection into the dorsal motor nucleus of the vagus nerve in rats.

Kainic acid injection into the dorsal motor nucleus of the vagus nerve (DMN) induced lesions in the glandular stomach of rats. A decrease in mucus production seemed to play an important role in the pathogenesis of the kainic acid-induced gastric lesions. On the other hand, by means of horseradish peroxidase tracing method, the original cells projecting to the DMN were identified in the central nucleus of the amygdala, several hypothalamic nuclei and the insular cortex. Considering that kainic acid is a long-acting neuronal excitant, it was suggested that the continual stimulation of DMN neurons facilitated gastric ulcer formation.

Animals↗
PubMed1989

[Histochemical study of external urethral sphincter in the rabbit. Analysis with construction of histograms].

Male rabbit's external urethral sphincter was examined by histochemical muscle fiber typing (myosin ATP-ase staining), and the analysis with construction of histograms regarding to muscle fiber types were performed. Rabbit's external urethral sphincter was predominantly composed of fast twitch (type 2) fibers (87.3%) as a whole. But the proportion of constituent fiber types varied according to the layers, i.e., the slow twitch (type 1) fibers constituted a relatively high percentage (33.4%) in the inner third layer, while few of the type 1 fibers were found in the outer third layer. The all histograms regarding to fiber type in different layers were normal bell-shaped distribution curves. The mena diameter of type 2 fibers (14.7 microns) was evidently larger than that of type 1 fibers (20.5 microns). All three kinds of muscle fibers equally tended to increase in size toward the outer direction, and in every three layers, the diameter of type 2 was larger than that of type 1 also. The definite differences in the proportion of fiber types and fiber sizes between layers may implicate that the inner and outer layers play different roles, i.e., continuous tonic constriction in the former and sporadic strong constriction of short duration in the latter, under different neural regulations. As far as rabbit's external urethral sphincter is concerned, sporadic strong constriction should be mainly dependent on the muscle fibers of large size composing the outer layer, especially the fast twitch fibers. It is possible that the rabbit is so adapted that it could interrupt urination promptly.

Animals↗
PubMed1989

[Treatment of gonococcal urethritis with norfloxacin].

Fifty six males with gonococcal urethritis were administered 600 mg of norfloxacin (NFLX) daily for 7 days, before the effects were examined. The pharmaceutical effects were studied on the third and the seventh day after administration. Pronounced effectiveness of 77.8%, effectiveness of 19.4% and ineffectiveness of 2.8% were found on the third day after administration, and pronounced effectiveness of 94.4%, effectiveness of 5.6% and ineffectiveness of 0% were found on the seventh day after administration. Effectiveness of 100% was obtained up to the seventh day. Minimum inhibitory concentration (MIC) of NFLX and ampicillin (AMPC) were determined for 14 strains. The peak of MIC of NFLX was found at 0.05 micrograms/ml and all strains were 0.78 micrograms/ml or lower. The peak of MIC of AMPC was 0.1 microgram/ml. MICs of both drugs were 0.78 micrograms/ml or lower, and resistant bacteria were not found. In view of the analyses of age distribution of patients and source of infection, the peak was found in the twenties and the source of infection in 64.7% were, so-called, professional women.

Adult↗
PubMed1989

[Influence of pregnancy and steroid hormones on interferon production of lymphocytes].

A study was done to investigate the involvement of interferon (IFN) in immunological acceptance of fetal allograft. IFN was induced by stimulating OK-432 from lymphocyte of pregnant and nonpregnant women as well as men. There was no difference in the IFN titer in these groups. In pregnant women there was no difference between trimesters, either. In addition, we examined the influence of sex steroid hormones such as progesterone and estrogen on IFN production by the lymphocytes of women and men. Generally, each steroid hormone suppressed the production of IFN. However, the extent of suppression varied with the concentration of hormones, resulting in different suppression curves for men and women in a physiological concentration. Differences in response by men and women were also noticed when interleukin 2 was added to examine whether it could reduce the suppression by steroid hormone. This unique sensitivity of female lymphocyte to steroid hormones may play a role in successfully taking a fetal allograft in pregnancy.

Adult↗
PubMed1989

[Gastric ulcer formation induced by kainic acid injection into the dorsal motor nucleus of the vagus nerve (DMN) and identification of the neuronal input to the DMN in rats].

Parasympathetic preganglionic cells innervating the stomach are located in the dorsal motor nucleus of the vagus nerve (DMN) in the medulla. The present experiments were carried out to elucidate that the long-lasting excitation of DMN neurons by kainic acid, a long-acting neuronal excitant, induced gastric ulcers and to identify the input neuronal systems projecting to the DMN by means of horseradish peroxidase (HRP) method in rats. Twenty four hours after kainic acid injection into the DMN, gastric ulcerative lesions were induced in 12 out of 14 rats. The ulcer index in experimental group, 10.2 +/- 6.5 mm, was significantly higher than that in the control group, 0.5 +/- 1.0. Mucus content in gastric mucosa was significantly lower than that of the control group. Fourty four hours after HRP injection into the DMN, HRP labeled cells were distributed from medulla to cortex, especially in medullary reticular formation, interpositis cerebellar nucleus, several hypothalamic nuclei, central amygdala nucleus and insular cortex. These results suggest that long-lasting excitation of DMN neurons facilitate gastric ulcer formation and that a decrease in mucus content in gastric mucosa plays an important role in the process of gastric ulcer formation by kainic acid injection into the DMN. Since the cortex, amygdala and hypothalamus has been shown to be closely associated with emotion and stress, it could be speculated that emotional changes and stress might induce the changes of excitability of DMN neurons via higher order neuronal systems.

Animals↗