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Biomedical subjects

N Yamaguchi

Publications and source records attributed to N Yamaguchi.

At least 631 records · Page 35Linked to original sources
PubMed1989

Kindling of the visual cortex in cats: comparison with amygdaloid kindling.

Kindling of the primary visual cortex (VC) was compared with that of the amygdala in cats. VC kindling was basically similar to kindling of the amygdala in that daily electrical stimulation can lead to the development of a generalized convulsion in most subjects, a growth of afterdischarges in their configuration and duration, and a reduction of the afterdischarge threshold. The kindling response of the VC differed from that of the amygdala in a number of respects, i.e., a high afterdischarge threshold, a different pattern of behavioral seizure development, an abrupt growth of electroclinical seizures coincident with the onset of a generalized convulsion, an intersubject variability in seizure susceptibility, and a marked seizure instability. In VC kindling the afterdischarge propagation into the amygdala was not observed until the generalized convulsion developed, and the early involvement of afterdischarge was seen in the pulvinar, lateral geniculate body, and superior colliculus. These data suggest that a neural mechanism different from amygdaloid kindling may participate in VC kindling, and that the subcortical structures of the visual system are involved in the preferential pathway for a seizure generalization from the VC.

Amygdala↗
PubMed1989

Reexamination of 123I-IMP-SPECT at interictal stages in adult partial epilepsy.

123I-IMP-SPECT scans at the interictal stages in 13 epileptic patients with normal X-ray CT findings were reexamined at intervals of 1.9 +/- 0.8 years. Interictal scalp EEGs were recorded a few hours after each SPECT scan. All of the SPECT abnormalities indicated focal hypofixation images of 123I-IMP, i.e. zones of a decreased rCBF reflecting a functional inactivation. Among 11 patients with the SPECT abnormalities in the first SPECTs, eight cases had the complete or partial regional reproduction of the abnormalities in the second SPECTs. As changes in the SPECT findings, an alteration from the abnormal SPECT images to normal images (normalization), the reverse change, the enlargement and reduction of hypofixation sites were seen. Also the EEG foci had various changes (right and left regional changes, etc.). Because of these SPECT and EEG changes, the regional relationship between the SPECT abnormalities and EEG foci altered in 7 patients (a change from disagreement to agreement, etc.). The high reproduction rate of SPECT abnormalities appears to increase the reliability or utility of SPECT scans for a regional diagnosis of epileptic foci. The present SPECT changes, especially the normalization or the severse change, suggest that the interictal epileptic focus may have a functional fluctuation. In addition, the causes of regional disagreement between the SPECT abnormalities and EEG foci were discussed on the basis of the present SPECT and EEG changes.

Adult↗
PubMed1989

Clinical studies of schizophrenia-like state in epileptic patients.

Six subjects who suffered from epileptic seizures followed by a schizophrenia-like state were examined. The mean duration between the onset of seizures and the psychotic state was 13.5 +/- 6.6 years (mean +/- S.D.). Five female subjects had episodic psychotic states and one man had a persistent one. Four subjects had localized temporal EEG abnormalities and the EEGs during psychotic states were different in each subject. During the psychotic state, no seizure was seen in the four subjects, a different seizure frequency in the episodic case and an unchanged frequency in the persistent case. The psychotic features were characterized by K. Schneider's first-rank symptoms. In order to understand the mechanisms of psychotic states, it will be useful to take into consideration the excitatory and inhibitory effects of neurotransmitters on limbic discharges.

Electroencephalography↗
PubMed1989

Effect of sotalol against reperfusion-induced arrhythmias in Sprague-Dawley and Wistar rats.

The effect of (+/-)-sotalol (a beta-blocker with class III antiarrhythmic activity) against reperfusion-induced arrhythmias was studied in artificially ventilated, open-chest, Sprague-Dawley and Wistar rats. Coronary artery occlusion was produced for 5 min and reperfusion allowed for 10 min. A somewhat different arrhythmic profile was observed between saline-treated rats of the 2 strains studied, with more Sprague-Dawley rats experiencing an irreversible ventricular fibrillation (VF) upon reperfusion, compared to Wistar rats, in whom a combination of reversible ventricular tachycardia (VT) and VF was more frequently observed. No difference in action potential characteristics and ventricular effective refractory period determined in vitro, nor in myocardial noradrenaline content, was found between the 2 strains of rats. (+/-)-Sotalol (5 and 10 mg/kg, IV) showed marked beta-blocking activity and reduced the mean duration of VT-VF in both strains studied. It also produced similar increases in action potential duration and refractory period in vitro in these 2 strains. In a different series of experiments, the antiarrhythmic action of the racemic form was compared to that of (+)-sotalol using Wistar rats. (+)-Sotalol had much less beta-blocking activity, and was found to be similarly effective against reperfusion-induced VT-VF. It is concluded that the antiarrhythmic effect of sotalol against reperfusion-induced arrhythmias may not be related to beta-adrenergic blockade but probably to class III type activity. Despite differences in the profile of reperfusion-induced arrhythmias between Sprague-Dawley and Wistar rats, both strains were sensitive to the antiarrhythmic action of (+/-)-sotalol.

Animals↗
PubMed1989

Direct evidence that an increase in aortic norepinephrine level in response to insulin-induced hypoglycemia is due to increased adrenal norepinephrine output.

This study reports on the major source of circulating norepinephrine that is known to increase, progressively, during sustained hypoglycemia induced by intravenous insulin administration. Plasma concentrations of epinephrine, norepinephrine, and dopamine were simultaneously determined for adrenal venous and aortic blood in dogs anesthetized with sodium pentobarbital. The model used allowed us to perform a functional adrenalectomy (ADRX), while continuously monitoring the adrenal medullary secretory function. Under basal conditions, the net output (micrograms/min) of adrenal epinephrine, norepinephrine, and dopamine were 0.169 +/- 0.074, 0.067 +/- 0.023, and 0.011 +/- 0.003, respectively. Plasma concentrations (ng/mL) of aortic epinephrine, norepinephrine, and dopamine were 0.132 +/- 0.047, 0.268 +/- 0.034, and 0.034 +/- 0.009. Following insulin injection (0.15 IU/kg, i.v.), the net output (micrograms/min) of adrenal epinephrine, norepinephrine, and dopamine increased gradually (p less than 0.05), reaching the values of 0.918 +/- 0.200, 0.365 +/- 0.058, and 0.034 +/- 0.007 30 min after insulin administration. Similarly, aortic epinephrine, norepinephrine, and dopamine concentrations (ng/mL) increased significantly (p less than 0.05) to 0.702 +/- 0.144, 0.526 +/- 0.093, and 0.066 +/- 0.024. The aortic glucose concentration (mg/dL) was diminished from 81.8 +/- 4.1 to 36.9 +/- 3.4 (p less than 0.01). After taking the blood sample at 30 min following insulin administration, ADRX was immediately performed. Five minutes after the onset of ADRX, the net output (micrograms/min) of adrenal epinephrine, norepinephrine, and dopamine increased further to 1.707 +/- 0.374 (p less than 0.05), 0.668 +/- 0.139 (p less than 0.05), and 0.052 +/- 0.017.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1989

Plasma catecholamine and glucose concentrations during hemorrhagic hypotension in anesthetized dogs.

Hemorrhage-induced hepatic glycogenolytic responses were compared in pentobarbital-anesthetized dogs with a temporary functional adrenalectomy (ADRX) and in dogs with an acute hepatic denervation (HNX). Plasma concentrations of catecholamines [CAs; epinephrine (E), norepinephrine (NE), and dopamine (DA)] were determined in aortic (AO), hepatic venous (HV), portal venous (PV), and adrenal venous (ADV) blood collected simultaneously before, during, and after hemorrhage (H). Plasma glucose (GL) concentrations were measured in AO and HV blood. AO blood was bled (5.3 +/- 0.5 ml.kg-1.min-1, n = 42) until AO systolic pressure dropped to half (72.9 +/- 4.7 mmHg) of its control value (148.0 +/- 4.4 mmHg), and the hypotension was maintained for 5 min. In control dogs (CTL; n = 12), H markedly increased ADV CAs with a predominant increase in E over NE and DA. AO CAs increased similarly. By contrast, however, changes in HV CAs were characterized by a significant increase in NE that was more pronounced than the increases in E and DA. The increases in NE were associated with significant increases in both HV GL and AO GL. In dogs with ADRX (n = 10), AO CAs remained unchanged during H, but both HV NE and HV GL rose concomitantly to an extent similar to that observed in CTL dogs. In dogs with HNX (n = 10), HV NE remained unchanged during H, but HV GL increased to an extent similar to that observed in dogs with ADRX, along with significant increases in AO CAs. In dogs with HNX combined with ADRX (n = 10), HV NE and AO CAs did not change at all during H, resulting in a marked attenuation (50%, P less than 0.05) of the increasing response of HV GL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗
PubMed1989

Refractory anemia terminating in acute megakaryoblastic leukemia (M7).

A 72-year-old man with refractory anemia (RA) developed overt megakaryoblastic leukemia after the course of RA with excess of blasts. The blasts were positive for platelet peroxidase activity and had platelet glycoproteins (GPs) such as GPIIb/IIIa and GPIIIa. The bone marrow biopsy at terminal stage disclosed marked fibrosis. The nature of the megakaryoblasts was investigated. The blasts did not differentiate morphologically into mature megakaryocytes with TPA addition. In vitro colony assay showed the failure of colony-forming unit, megakaryocyte growth in peripheral blood. The pathogenesis of myelofibrosis in our patient is discussed.

Aged↗
PubMed1989

[Questionnaire survey of full-time occupational health physicians in Japan].

In August 1987 the University of Occupational and Environmental Health conducted a mail questionnaire survey on occupational health physicians (OHPs) located throughout Japan. The objective was to obtain preliminary information concerning the actual situation of OHPs together with their opinions on post-graduate training in this field. A summary of the results based on 187 valid responses (valid response rate = 59.4%) is as follows: 1. Age distribution of the respondents was in excess of 55 years of age (mean age of 61.4 yr), suggesting aging of the work force. 2. Comparison of the present age with period in present position revealed that a significant proportion of the respondents assumed their current position following retirement from clinical service. 3. Routine work schedules such as clinical activities and making site visits within factory tended to be influenced by the number of employees. 4. Conduct of special physical examinations on workers in hazardous environments was rated the highest among the necessary abilities of OHPs. 5. It was found that 30-34 years of age and 2-5 years of clinical experience were the minimal qualifications for a full time OHP.

Adult↗
PubMed1989

Interleukin-5 induces maturation but not class switching of surface IgA-positive B cells into IgA-secreting cells.

There is a body of evidence suggesting that IgA production is regulated by helper T cells or their products. To elucidate molecular mechanisms of IgA production, the role of lymphokines in the in vitro antigen-specific and polyclonal IgA responses was examined. Supernatants from antigen-stimulated T cells or mitogen-stimulated T-cell clones can enhance 2,4-dinitro phenyl (DNP)-specific IgM, IgG1 and IgA production in cultures of DNP-ovalbumin (OVA)-stimulated T-cell-depleted spleen cells from DNP-keyhole limpet haemocyanin-primed mice. The IgA enhancement was inhibited by anti-IL-5 monoclonal antibody. Purified recombinant IL-5 could also enhance anti-DNP IgA production in a dose-dependent manner. This enhancing effect was not substituted by IL-1, IL-2, IL-3 or IL-4. Polyclonal IgA secretion of lipopolysaccharide-stimulated normal B cells was augmented preferentially by IL-5, but not by IL-4. Surface IgA-positive (sIgA+) B cells, but not surface IgA-negative B cells, responded to IL-5 for the development of IgA-secreting cells. Limiting-dilution analysis revealed that IL-5 increases the frequency of IgA-secreting cells in sIgA+ B-cell populations. These results indicate that IL-5 plays an essential role in the antigen-specific and polyclonal IgA formation as a maturation-inducing factor rather than class-switching factor.

Animals↗
PubMed1989

Ultrastructural immunogold labelling of vimentin filaments on postembedding ultrathin sections of arachnoid villi and meningiomas.

An immunoelectron microscopic technique for the labelling of vimentin intermediate filaments on postembedding ultrathin sections is reported. Arachnoid villi obtained at autopsy and meningiomas at surgery were fixed in 1% paraformaldehyde for 30 minutes, embedded without postfixation in Epon-Araldite mixture and polymerized at 37 degrees C for 3 weeks. Ultrathin sections were etched in 2% KOH for 3 minutes and incubated with anti-vimentin monoclonal antibodies which were subsequently labelled with goat anti-mouse IgG coupled to colloidal golds. All of these labelling procedures were consistently performed within 4 hours. In both arachnoidal and meningioma cells, immunogolds preferentially decorated the intermediate filaments in proportion to the concentration. Very few gold particles were seen over the nucleus, Golgi zone, mitochondria and the extracellular connective tissue fibres. The present technique may be applied to the immunogold labelling of intermediate filaments on postembedding ultrathin sections.

Antibodies, Monoclonal↗
PubMed1989

[Characterization of an analog enzyme to cathepsin L produced by tumor cells].

The activity of cathepsin L is examined in the culture supernatants of 38 human, murine and hamster tumor cell lines. It is found that all cell lines secrete the enzyme possessing cathepsin L activity. The supernatant of HPC-YP cell cultures is purified and characterized as the enzyme preparation, because this supernatant shows the highest cathepsin L activity. The results indicate that the enzyme produced in HPC-YP cells is different from cathepsin L of normal liver in the several points. The molecular weight of the enzyme is 68 kd, whereas it is 34 kd for the liver cathepsin L. The enzyme is more stable to heat treatment and at the various pH than the liver cathepsin L. Furthermore, the inhibitors, which inhibit the liver cathepsin L activity, do not inhibit the activity of this enzyme. It is concluded that the enzyme showing cathepsin L activity in the culture supernatants of human tumor cells is different from human normal liver cathepsin L.

Adenocarcinoma↗
PubMed1989

Expression level of the retinoblastoma susceptibility gene is elevated in simian virus 40-transformed cells.

We examined the level of mRNA of the retinoblastoma-susceptibility gene (Rb gene) in simian virus 40 (SV40)-transformed primate cells. The mRNA level of Rb gene was elevated in SV40-transformed cells compared with that in untransformed parental cells. The level of Rb message was also increased by SV40 infection on monkey kidney CV-1 cells. The level of Rb gene mRNA in SV40-transformed or SV40-infected cells was about fourfold higher than that in controls. These observations suggest that Rb gene is one of the cellular genes which can be elevated by SV40 directly or indirectly.

Antigens, Polyomavirus Transforming↗
PubMed1989

[Intracytoplasmic eosinophilic inclusions in dorsal root ganglia and spinal nerve roots from an autopsy case of unusual familial ataxia with cerebrospinal fluid abnormality].

Studies were performed on the light and electron microscopic structures of the dorsal root ganglia (DRG) and spinal nerve roots of the 4th lumbar nerve obtained by autopsy from a 49-year-old man with unusual familial ataxia, who showed varied neurological manifestations such as progressive ataxia, action tremors, pyramidal tract signs, mild deep sensory disturbances and autonomic dysfunctions during a 30-year period of illness, and had 2 siblings, one male and female, similarly affected and close consanguineous marriages in his family. On laboratory examinations, blood chemistry disclosed no significant findings. Repeated spinal taps showed constant xanthochromia and elevated protein in the cerebrospinal fluids. A PEG and cranial CTs revealed a progressive brain atrophy. NCVs and EMGs in the extremities were within normal limits. There was no chromosomal abnormality. Light microscopically, intracytoplasmic eosinophilic inclusions (IEIs) with pale rim, which showed varied sizes and rounded shapes, occurred within neurons in the DRG, particularly in small neurons. Many of the small neurons had numerous IEIs, and several rounded granules with a high degree of eosinophilia, measuring below 5 microns in diameter. Generally the small neurons showed atrophic, while most large neurons showed no remarkable change although they had a small number of IEIs and granules located in the perikaryal periphery. Most satellite cells, and some Schwann cells in the DRG, ventral and dorsal roots had IEIs similar to those seen in the neurons. No IEIs occurred intraaxonally, and there was seen no degenerative process in the DRG and roots except a connective tissue fiber proliferation in the DRG.(ABSTRACT TRUNCATED AT 250 WORDS)

Ataxia↗
PubMed1989

[Studies on the mechanism of glomerular localization of immune complexes (1). Localization of preformed native ferritin immune complexes on the glomerular basement membrane in passive serum sickness nephritis of mice].

Immune complex deposits found on the subepithelial side of the glomerular basement membrane (GBM) are characteristic of membranous glomerulonephritis. In order to clarify the mechanism of subepithelial immune complex deposition, we investigated the manner of localization of preformed immune complexes (IC) composed of native ferritin (NF) and anti NF antibody (aNFab) in a 40-fold antigen great excess using the system of passive serum sickness nephritis of mice. The following results were obtained. (1) The ferritin particles in the GBM of animals given NF alone, as controls, were mainly restricted to the lamina rara interna (LRI) with very few penetrating the entire depth of the GBM. (2) In animals given the IC, greater numbers of ferritin particles were seen, in comparison with the control animals, not only in the lamina densa (LD) but also in the lamina rara externa (LRE). (3) Immunoelectron microscopy (IEM) demonstrated that each NF particle was accompanied by aNFab, which was found to be peroxidase positive material, throughout the GBM. (4) On the grounds that ICs were prepared in Ag great excess, it is suggested that ICs seen in the GBM are composed of a low avidity antibody with a low Ag/Ab ratio, probably Ag1Ab1. From these results, it is suggested that circulating ICs are necessary to give rise to IC deposition on the GBM and that NF and aNFab exist together as ICs throughout the GBM. We concluded that subepithelial IC deposits arise from the circulation, and that after GBM trapping, circulating small-sized IC can pass through the LD to reach the subepithelial side of GBM.

Animals↗
PubMed1989

[Studies on the mechanism of glomerular localization of immune complexes (2). Localization of non-dissociable immune complexes on the subepithelial side of the glomerular basement membrane].

In order to investigate whether preformed (circulating) immune complexes (IC) can localize in the subepithelial side of the glomerular basement membrane (GBM), non-dissociable covalently cross-linked IC (cov. IC) composed of native ferritin (NF) and anti NF antibody (aNFab) were preformed in a 2 step reaction using the bifunctional reagent, toluene-2,4-diisocyanate (TDI). Molecular weight of cov. IC was about 58 x 10(4) dalton, which suggests that the cov. IC was composed of Ag1Ab1 lattices. The GBM of mice given cov. IC intravenously showed that deposition of cov. IC was not only in the lamina rara interna but also, with time, in the lamina densa and lamina rara externa. The size of cov. IC and the distribution in the GBM described above were similar to those we studied previously using preformed dissociable NF and aNFab complexes in a 40-fold antigen great excess. From these results, we concluded that preformed immune complex in vitro can pass through the lamina densa as intact IC to give rise to the subepithelial area without dissociation or reformation. That is, the subepithelial IC deposits arise from the trapping of small-sized IC derived from the circulation.

Animals↗
PubMed1989

Antitumor activity of an extract of Cordyceps sinensis (Berk.) Sacc. against murine tumor cell lines.

A warm water-extract (ECS) prepared from dried Cordyceps sinensis (Berk.) Sacc., a Chinese traditional medicine, was tested for antitumor activity in vivo and in vitro. Ehrlich ascites carcinoma cells (EAC), allogeneic to ICR mice and Meth A fibrosarcoma (Meth A), syngeneic to BALB/c mice were used as the target tumor cell lines. Mice were inoculated i.p. with 1 x 10(6) EAC or 1 x 10(5) Meth A on Day 0, and ECS or saline (control) was injected i.p. to the mice from Day 1 to Day 4. ECS-treatment increased the median survival time of the allogeneic mice inoculated with EAC to 316% of the control. Eight of the 10 ECS-treated mice survived on the 60th day (Day 60) after EAC implantation. ECS-treatment also increased the median survival time of the syngeneic mice inoculated with Meth A to 312% of the control. Half of the ECS-treated mice survived on Day 60. On the other hand, no cytotoxic effect of ECS was found on either EAC or Meth A in vitro. The antitumor effect of ECS seen in the allogeneic mice was significantly reduced when the mice received whole body X-irradiation (5 Gy) before EAC implantation. These results suggest that the antitumor effect of ECS may be mediated through its immunomodulating action.

Animals↗