Biomedical subjects

N Yamaguchi

Publications and source records attributed to N Yamaguchi.

At least 343 records · Page 19Linked to original sources

PubMed1994

Effects of bromocriptine in Huntington chorea. Case report.

1. The effects of bromocriptine (BC) on choreiform movement were compared with those of bromperidol (BP) and fluphenazine (FLZ) in a patient with Huntington disease. The patient (male, 42 years old) was treated with BP (15 mg/day, 4 weeks), FLZ (3 mg/day, 4 weeks), low dose of BC (5 mg/day, 4 weeks) and relatively high dose of BC (10 mg/day, 8 weeks). The CSF content of homovanilic acid (HVA) was assayed at last day of the each drug trial. The efficacy of the drugs was evaluated by electromyography. 2. Although BP and FLZ did not succeed to ameliorate the choreiform movement, both low dose and high dose BC showed rapid improvement of the involuntary movement. The CSF HVA concentration was 35.0 ng/ml before beginning treatment. Whereas FLZ and high dose of BC substantially increased the levels of HVA after the dosage (49.3 and 53.1 ng/ml, respectively), moderate increase of HVA (41.5 ng/ml) was observed when the low dose of BC was administered. These observations suggest that increase of CSF HVA might be necessary for clinical improvement of choreiform movement but not correlate with the degree of improvement and dopamine agonists could be useful drug for the treatment of choreiform movement which is refractory to the administration of neuroleptics.

Adult↗

PubMed1994

The effect of age on plasma level of setiptiline maleate in depressed patients.

1. Setiptiline maleate (SPT) was administered orally to 45 subjects aged 22-86 years and steady state plasma levels were determined by mass fragment chromatography (GC-MF) to examine the effect of aging on those values. 2. There was a significant correlation between the plasma levels and daily dose. However, there was a wide interindividual variability. 3. Dose-corrected plasma level (DC-PL), or values corrected by dividing the plasma level by daily dose/body weight, was used as the systemic drug clearance parameter. 4. DC-PL was compared among 7 age groups of the subjects distributed in 10-year-intervals. DC-PL showed no difference among groups of subjects between the > 29 years bracket to the 70 years bracket, but showed significantly higher values in those in the > 80 bracket compared to all age groups and subjects in the < 79 bracket. 5. There was a significant correlation between the age of patients and DC-PL according to polynomial response curve analysis. Regression analysis yielded the equation y = -52.72 + 7.05 x -0.17 x2 + 0.01 x3 (n = 45, r = 0.49, p < 0.01).

Adult↗

PubMed1994

Limited visual search on the WAIS Picture Completion test in patients with schizophrenia.

The Wechsler Adult Intelligence Scale was examined in 39 patients with schizophrenia, the visual cognitive task of Picture Completion showing the most impairment. In order to clarify the role of eye movements in Picture Completion, searching eye movements in 12 schizophrenic patients and 12 normal controls were recorded using an infrared eye-mark recorder. Schizophrenic patients as a group showed fewer eye fixations, and shorter total length of scan path than normal controls during the last 10 s of exposure to the picture. However, the patients who responded correctly, did so with a similar number of fixations and similar length of total scan path to those of normal controls. The patients who failed in the task took a significantly longer time for the first survey of the picture than the successful patients and normal controls. The less efficient strategy of visual search seen in the patients who failed might be a manifestation of poor reality testing and be related to frontal lobe dysfunction.

Adult↗

PubMed1994

Effect of inhibition of hepatic fatty acid oxidation on metabolic and hormonal responses to exercise in rats.

The purpose of the present study was to assess the effects of 2-mercaptoacetate (MA), an inhibitor of hepatic fatty acid oxidation, on the metabolic and pancreatic hormone response to a prolonged (3 h) swimming exercise. All rats were first adrenodemedullated and were either submitted for 3 weeks to a normal (5% fat) or a medium-fat diet (MF; 18% fat). After being submitted to an exercise swimming habituation programme for one week, rats under both dietary conditions were either injected with a bolus dose of MA (600 mumol/kg; ip) or with a saline solution. MA and saline injected rats were either sacrificed after a 3-h swimming exercise or after a 3-h resting period. Administration of MA was associated with a lower level of beta-hydroxybutyrate after exercise in rats fed the MF diet, higher resting and exercising blood glucose levels in rats fed the MF diet, and higher resting and exercising levels of hepatic glycogen in rats fed a normal diet. There were, however, no significant effects of MA on free fatty acid, insulin, glucagon, epinephrine, and norepinephrine concentrations in both dietary conditions either at rest or after exercise. Therefore, the present data do not provide any evidence that the administration of MA, an inhibitor of hepatic fatty acid oxidation, influences the pancreatic hormonal response to exercise. There was also no evidence of a lowering effect of MA on blood glucose levels during exercise.

3-Hydroxybutyric Acid↗

PubMed1994

Substitution of cysteine for glycine-946 in the alpha 1(I) chain of type I procollagen causes lethal osteogenesis imperfecta.

Procollagen synthesized by skin fibroblasts from a patient with a lethal variant of osteogenesis imperfecta has been characterized. After pepsin digestion of the type I procollagen, a portion of the alpha 1(I) chains was recovered as a disulfide-bonded dimer. Cyanogen bromide peptide mapping suggested that a new cysteine residue was present in the alpha 1(I)CB6 fragment. Sequencing of cloned cDNAs prepared using mRNA from the proband's fibroblasts demonstrated that some of the clones contained a single base mutation that converted the glycine codon in amino acid position 946 of the alpha 1(I) chain to a cysteine codon. The thermal stability of the molecules was markedly lower than that in the case of the normal control.

Base Sequence↗

PubMed1994

Human laminin M chain: epitope analysis of its monoclonal antibodies by immunoscreening of cDNA clones and tissue expression.

We have produced four monoclonal antibodies (mAbs) against human placenta laminin purified by immunoaffinity chromatography. Three clones, 2D9, 3DM, and 4F1, recognized 320 kDa (M) chain of the laminin and the other one, 3DB, recognized B2 chain. One cDNA clone (HLM-1, 3.5 kb) was immunoscreened from human placenta cDNA library using 2D9, and three further overlapping cDNA clones (HLM-2, HLM-3, and HLM-4) covering 2.0 kb were isolated. Nucleotide sequencing and fusion protein analysis demonstrated that the amino acid sequence deduced from HLM-1 coincided with that of the G-domain of human merosin chain, and HLM-2, HLM-3, and HLM-4 encoded the long-arm and EGF-like domain of M chain. The binding regions of 2D9 and 3DM to M chain were defined as homologous repeating sequences of G2-G3 region of G-domain and the carboxy-terminal region of the long-arm, respectively. The extents of identity of amino acid sequences of the long-arm and EGF-like domains between human M chain and A chain were about 37% and 52%, respectively, which were lower than between mouse and human A chains. Northern blot analysis revealed that M chain mRNA, 8.6 kb, was highly expressed in heart and placenta, but less highly expressed in skeletal muscle, brain, and lung. Immunostaining showed selective distributions of M chain in nerve fibers in the dermis and mesangial matrix of the kidney, and B2 chain in subepidermal and kidney glomerular basement membranes.

Amino Acid Sequence↗

PubMed1994

K-ras and p53 alterations in genomic DNA and transcripts of human pancreatic adenocarcinoma cell lines.

We analyzed 15 human pancreatic adenocarcinoma cell lines for alterations of the K-ras and the p53 genes and their transcripts. In 11 cell lines (73.3%), point mutations of the K-ras gene were found at codon 12 in exon 1. In 9 cell lines one allele was mutated and the other was wild type, and both the alleles were expressed into mRNA. In one cell line both alleles of codon 12 were mutated to TGT and GTT, respectively, but only TGT was transcribed into mRNA. Alterations in mRNA of the p53 gene were detected in 10 cell lines (66.7%). Analysis of the genomic sequence of the p53 gene revealed that the alterations consisted of 6 cases of base pair substitutions and 1 case of 1-bp deletion in evolutionarily conserved exons 5 to 8, 2 cases of splicing mutations in exon 4, and 1 case of novel deletion from exons 2 to 9. In 14 cell lines (93.3%), alterations were identified in the K-ras or p53 gene. Of these, 4 cell lines harbored K-ras mutations without p53 alteration, whereas 3 cell lines exhibited p53 alterations without K-ras mutation. Thus, it is suggested that activation of the K-ras gene and inactivation of the p53 gene are strongly and cooperatively associated with pancreatic carcinogenesis.

Adenocarcinoma↗

PubMed1994

Sudden cerebral hypoperfusion enhances respiratory suppression in hypoxic newborn piglets.

The relationship between sudden cerebral hypoperfusion and sudden respiratory suppression was investigated in newborn piglets. A total of 11 experiments on five newborn piglets were divided into three groups: normoxic, hyperoxic and hypoxic. The sudden cerebral hypoperfusion was created by manual compression of the Arteria carotis communis and Vena jugularis interna. Respiratory suppression was calculated by measuring the duration of apnea and the percent reduction of respiratory amplitude. The means of apnea duration in normoxic and hyperoxic groups were 6.6 +/- 0.8 and 1.2 +/- 2.4 s, respectively, while two experiments on the hypoxic group showed 8.4 s and complete cessation of respiration in one of them. The per cent reductions of respiratory amplitude in the normoxic and hyperoxic groups were 23.3 +/- 8.5 and 17.6 +/- 11.7%, respectively. In the hypoxic group, one of two experiments showed a 22.7% reduction, which was equivalent to that of the normoxic group. We conclude that sudden cerebral hypoperfusion enhances respiratory suppression, especially when it coincides with hypoxia. The phenomenon may be one of the possible causes for a certain type of sudden infant death syndrome. Further study will be undertaken to elucidate the direct effects of the mechanism of cerebral hypoperfusion on respiratory suppression.

Animals↗

PubMed1994

Intracoronary infusion of bradykinin: effects on noradrenaline overflow following reperfusion of ischemic myocardium in the anesthetized dog.

OBJECTIVE: The aim of this study was to investigate the effects of intracoronary bradykinin (BK) infusion on noradrenaline release and ventricular arrhythmias induced by coronary occlusion and reperfusion in the anesthetized dog. METHODS: 14 anesthetized adult mongrel dogs of either sex underwent a 60 min occlusion of the left anterior descending coronary artery (LAD) followed by a 30-min reperfusion period. BK (1 ng.kg-1.min-1, n = 7), or its vehicle (Lactate Ringer, n = 7), infusions just distal to the left coronary ostium started 15 min before the LAD occlusion and were maintained throughout the experimental period. An epicardial vein, running parallel to the LAD was cannulated to enable the biochemical determinations. The effects of BK on ventricular arrhythmias, cardiac noradrenaline and lactate releases and creatine kinase activity were assessed. RESULTS: BK significantly reduced the amount of noradrenaline released at reperfusion by ischemic myocardium (from 82.1 +/- 31.7 to 11.9 +/- 9.6 ng.min-1), as well as plasma creatine kinase activity at 30 min of reperfusion. This is accompanied by a significant reduction in the incidence of reperfusion-induced sustained ventricular tachycardia. CONCLUSION: This suggests that the protective effect of bradykinin against reperfusion-induced sustained ventricular tachycardia could be associated with a reduction in cardiac noradrenaline release.

Animals↗

PubMed1994

Evaluation and interpretation of symptom structures in patients with schizophrenia.

Seventy Japanese DSM-III-R schizophrenic patients were assessed for 30 clinical symptoms using the Positive and Negative Syndrome Scale (PANSS) of Kay et al. Principal component analysis was applied to the full item set of this scale and disclosed 5 orthogonal independent symptom groups: negative, hostile/excited, thought-disordered, delusional/hallucinatory and depressive components. Our results provided further support of the contention that more than 2 (i.e., positive and negative) dimensions are required to account for structures of the schizophrenic symptoms.

Adolescent↗

PubMed1994

Cerebral palsy of cystic periventricular leukomalacia in low-birth-weight infants.

We studied ultrasound findings and neurodevelopmental outcome of 24 infants weighing 2500 g or less with cystic periventricular leukomalacia. Fourteen infants had symmetrical cysts in the parietal or occipital region (group 1) and 10 had non-symmetrical cysts (group 2). Each infant was followed for more than 4 years of age (mean 5 years and 7 months). Twenty out of 24 (83.3%) children developed cerebral palsy. All of group 1 had cerebral palsy (8 diplegia and 6 ataxic diplegia), while 6 (60%) in group 2 developed cerebral palsy (4 diplegia and 2 hemiplegia). There was a significant difference in the incidence of cerebral palsy and motor ability between the two groups. The size and site of the cyst did not predict cerebral palsy. The presence of symmetrical cysts in the parietal or occipital region is a highly reliable neurosonographic finding for predicting cerebral palsy.

Cerebral Palsy↗

PubMed1994

Hypocarbia and cystic periventricular leukomalacia in premature infants.

One hundred sixty seven survivors among very low birthweight infants with a gestational age of less than 35 weeks have been studied prospectively. The purpose of this study was to clarify the relationship of severe prenatal and perinatal complications and hypocarbic alkalosis, defined as a carbon dioxide tension (PaCO2) of less than or equal to 2.67 kPa and a pH of 7.50 or greater during the first 24 hours of life, to cystic periventricular leukomalacia (PVL) depicted by serial cranial ultrasonographic examinations. Complications occurred in 16 infants, five of whom presented with PVL, while eight of 151 infants without complications had PVL. Twenty six of the infants had hypocarbic alkalosis, six with evidence of PVL, and seven of the 136 infants without hypocarbic alkalosis had PVL. These results suggest a significant relationship of complications and hypocarbic alkalosis to PVL. Mechanical ventilation should be managed carefully in premature infants to avoid PaCO2 of lower than 2.67 kPa.

Alkalosis↗

PubMed1994

Adrenal medullary counterregulatory response to hypoglycemia in dogs with hepatic cross perfusion.

The present study was conducted to investigate adrenal medullary response to cross perfusion of the liver in postabsorptive anesthetized dogs. The liver of the first dog (recipient) was perfused with vena caval and aortic blood of the second dog (donor) through the portal vein and hepatic artery, respectively. Hepatic venous blood was returned to the donor through an intracaval double-lumen hepatic catheter placed in the vena cava of the recipient. A portacaval shunt was made through the right femoral vein in the recipient. Upon the cross perfusion, normoglycemic clamp in the recipient was started to compensate the loss of hepatic glucose input into the systemic circulation. When the glucose infusion was discontinued, aortic glucose level rapidly declined, within 45 min, from 125.2 +/- 10.2 to 30.3 +/- 4.6 mg% (p < 0.05, n = 6) along with a similarly rapid decline of aortic insulin level. Inversely, both adrenal venous epinephrine and norepinephrine increased significantly (163.2 +/- 88.0 vs. 794.9 +/- 55.7 ng/mL (p < 0.05) and 36.6 +/- 22.4 vs. 119.7 +/- 15.3 ng/mL (p < 0.05), respectively; n = 6) during this hypoglycemic period. However, in the donor, glucose level did not change either in aortic or vena caval blood, indicating that the recipient's liver was perfused with normal blood glucose levels. In the control group in which the normoglycemic clamp in the recipient was continued during the cross perfusion, both aortic glucose and adrenal venous catecholamines remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Medulla↗

PubMed1994

Norepinephrine and dihydroxyphenylglycol effluxes from sympathetic nerve endings during hypoxia and reoxygenation in the isolated rat heart.

The present experiments were carried out in isolated rat hearts perfused according to the Langendorff method at a constant pressure of 10 kPa. The aim was to measure norepinephrine (NE) overflow and its deaminated metabolite dihydroxyphenylglycol (DOPEG) by changing the composition of the buffer perfusing the heart to simulate hypoxia. When aerobic and glycolytic pathways were simultaneously reduced, NE and DOPEG overflow increased 711 and 145%, respectively, after 30 min, compared with control values of 0.45 +/- 0.06 and 0.66 +/- 0.7 ng.min-1.g-1 of heart (n = 8, p < 0.05). Whereas NE leakage decreased sharply after reoxygenation and glucose addition, DOPEG continued to increase up to 260% after 5 min of normal reperfusion. This mechanism was calcium independent and inhibited by 80% with desipramine (1 microM), confirming the role of the uptake I carrier, which reversed its normal transport direction. Neuropeptide Y, a marker of exocytotic release, did not increase in the perfusate with the progression of hypoxia, which supports the hypothesis of a nonexocytotic release. Tyramine (1 microM) significantly enhanced NE outflow by displacing the amine from its storage vesicles through a calcium-independent mechanism, indicating that a pool of NE was still available. In the presence of 1 microM clorgyline (a monoamine oxidase A inhibitor) but not deprenyl (a monoamine oxidase B inhibitor), NE outflow increased 934% and DOPEG only 40% at 30 min (n = 6, p < 0.05 versus control hearts).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Effects of Buthus martensii Karsch scorpion venom on the release of noradrenaline from in vitro and in vivo rat preparations.

The aim of this study was to test the neuronal effects of the Chinese Buthus martensii Karsch (BMK) scorpion venom in vivo and in vitro in order to understand the mechanism involved in the cardiovascular pressor effect of this venom. In conscious unrestrained rats, administration of 100 micrograms/kg i.v. BMK venom induced an increase in blood pressure, which was associated with a significant increase in plasma noradrenaline. In isolated atria, BMK also induced an increase in the stimulation-induced release of [3H]noradrenaline in a dose-dependent manner. The modulatory effect of agents acting at sympathetic prejunctional adrenoceptors on [3H]noradrenaline release was not altered by BMK venom administration. Finally, it was observed that 100 micrograms/mL BMK venom increased the intracellular calcium concentration in acutely dissociated sympathetic neurons from adult rat superior cervical ganglion. This action appeared to be mainly due to an influx of extracellular calcium. BMK venom induced a small rise in intracellular calcium in the absence of external calcium, indicating that it may also mobilize calcium from intracellular stores. The results observed in this study suggest that BMK venom may induce pressor responses by releasing noradrenaline from the sympathetic nerve terminals and that activation of neuronal calcium channels may be involved in that process.

Animals↗

PubMed1994

Nifedipine inhibits adrenal but not circulating catecholamine response to nicotinic stimulation in dogs.

We investigated whether dihydropyridine-sensitive L-type Ca2+ channels are implicated in adrenal and sympathetic neural catecholamine release in response to nicotinic stimulation by 1,1-dimethyl-4-phenylpiperazinium (DMPP), a selective cholinergic nicotinic agonist, in dogs anesthetized with pentobarbital sodium. Plasma epinephrine and norepinephrine concentrations were measured in adrenal venous and aortic blood by a high-performance liquid chromatography-electrochemical method. In the vehicle control group, intravenous injection of DMPP (15 micrograms/kg iv) produced a significant increase in adrenal venous catecholamine output and aortic catecholamine concentration. These increasing responses were highly reproducible on the repetition of DMPP injection given 30 min after the first injection. In dogs receiving nifedipine (100 micrograms/kg iv), the net increase in adrenal venous epinephrine and norepinephrine output in response to DMPP was attenuated by 42% (P < 0.05), while no significant changes were observed in the aortic catecholamine response to DMPP. In dogs treated with pentolinium (1 mg/kg iv), both adrenal epinephrine and norepinephrine responses to DMPP were inhibited by 67% (P < 0.05) and 84% (P < 0.05), respectively. Furthermore, pentolinium inhibited aortic catecholamine response to DMPP by > 95% (P < 0.05). The present study suggests that DMPP-induced release of adrenal catecholamines was mediated, at least in part, through mechanisms involving dihydropyridine-sensitive L-type Ca2+ channels under in vivo conditions. By contrast, however, the results also suggest that dihydropyridine-sensitive L-type Ca2+ channels were not implicated in the neurotransmission at the level of sympathetic ganglions.

Adrenal Glands↗

PubMed1994

Utility of 123I-IMP SPECT brain scans for the early detection of site-specific abnormalities in Creutzfeldt-Jakob disease (Heidenhain type): a case study.

Serial changes in brain imaging of regional cerebral blood flow with single photon emission computed tomography (SPECT) using N-isopropyl-(iodine-123) p-iodoamphetamine (123I-IMP) were observed in a patient with probable Heidenhain type of Creutzfeldt-Jakob disease, which was characterized by the initial onset of visual symptoms. Corresponding to the visual signs and periodic synchronous discharges localized in the bilateral parietal and occipital regions on EEG, focal hypoperfusion images in the occipital lobes were detected on the SPECT scan before brain X-ray computed tomography and magnetic resonance imaging showed any abnormalities. These results suggest that SPECT brain imaging is useful in the early detection of site-specific abnormalities in Creutzfeldt-Jakob disease.

Aged↗

PubMed1994

Case study of monosymptomatic delusion of unpleasant body odor with structural frontal abnormality.

We report a 63-year-old man with a monosymptomatic delusion of unpleasant body odor contracted at the age of 61 years, who believed that his body reeked of some type of paint. He had symmetrical atrophy in the bilateral frontal lobes of unknown etiology on MRI. Further, quantitative rCBF measurement with SPECT brain scan using 99mTc-HMPAO showed relative hypoperfusion localized in the bilateral frontal lobes. EEG, neurological and neuropsychological tests were all normal, including the WAIS-R and Wechsler Memory Scale tests. However, he showed poor results on the Wisconsin Card Sorting test, presumably on account of frontal dysfunction, attaining only two categories with frequent perseverative errors. Although it is undetermined whether the illness in this case can be classified as organic delusional syndrome or paranoid disorder according to DSM-III-R criteria, these results imply that delusions are associated with frontal lobe abnormality.

Atrophy↗