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Biomedical subjects

M Ito

Publications and source records attributed to M Ito.

At least 55 records · Page 3Linked to original sources

Alterations of benzodiazepine receptor binding in tremor rats with absence-like seizures.

Tremor rats begin to exhibit clinical or electrical absence-like seizures after 6 weeks of age, and by 14 weeks of age, all have seizures. Central-type benzodiazepine receptor binding was investigated in tremor rats and control rats, aged 4 weeks and 16 weeks. Significantly lower benzodiazepine receptor density and no differences in affinity were found in the hippocampus of the tremor rats in comparison with that of control rats at both ages. This abnormality is considered to be due to a tremor gene and may be the cause of absence-like seizures in tremor rats. A significantly lower receptor density was found in the cerebellum at 4 weeks of age in the tremor rats than in the control rats. These changes may be related to tremorous movements in the tremor rats. Receptor density was significantly lower in the brainstems of tremor rats and control rats at 16 weeks of age than at 4 weeks of age, and the decrease was more marked in control rats. These facts may reflect a reduced decrease in the response to the dysfunction of gamma-aminobutyric acidergic neurons, or the function of the gamma-aminobutyric acid/benzodiazepine receptor system may be secondarily increased to suppress seizures in 16-week-old tremor rats.

Animals

Intrinsic and drug-induced seizures of adult and developing gerbils.

Seizures elicited by posture change and intraperitoneal administration of convulsants were studied ontogenetically in the Mongolian gerbil (Meriones unguiculatus). In posture change, the first signs of seizure appeared after age 6 weeks with maximal frequency at 8-9 weeks. Adults developed complex, but stereotyped, seizures. Facial twitch was followed by the generalized convulsion, further progressing to trembling of the limbs and then kicking of the hindlimb (full seizure) after 55 days of age. Pentylenetetrazole induced a seizure similar to the full event in gerbils as young as 37 days of age. The seizure pattern elicited by strychnine or glutamate was different from that of pentylenetetrazole.

Animals

Monoclonal antibody analysis of keratin expression in carcinomas of sweat glands.

Characteristics of keratins of five carcinomas of sweat gland origin were immunohistochemically investigated with several antikeratin monoclonal antibodies with differing specificities. Specimens were obtained from two cases of mucinous carcinoma of the skin, two cases of classic type of eccrine adenocarcinoma, and a case of eccrine porocarcinoma. The tumor cells of mucinous carcinoma expressed only simple epithelial keratins. In a case of eccrine adenocarcinoma, simple epithelial keratin 19 was diffusely expressed. The expression of the other simple epithelial keratins was confined to the luminal cells, whereas the remaining tumor cells further expressed stratified epithelial keratins. Eccrine porocarcinoma and a second case of eccrine adenocarcinoma did not express simple epithelial keratins, although stratified epithelial keratins were diffusely expressed. These data suggest that carcinomas of sweat glands express various combinations of simple and stratified epithelial keratins. Development of additional data along these lines may help to further define their classification.

Adenocarcinoma

Simultaneous visualization of cortical barrels and horseradish peroxidase-injected layer 5b vibrissa neurones in the rat.

1. Using diaminobenzidine (DAB) as a chromagen, horseradish peroxidase-injected neurones and cytochrome oxidase-stained barrels were visualized simultaneously in the rat vibrissa cortex. Neurones were initially tested during extracellular recording for responses to whisker deflections. This was followed by intracellular injection of the soma with horseradish peroxidase (HRP) and histological processing to visualize the HRP-stained neurone in an incubation solution which contained, in addition to DAB, cytochrome C for cytochrome oxidase (CO) reaction of the barrels. 2. Recording and intracellular staining were made in layer 5b under urethane anaesthesia. CO-stained barrels were observed in layer 4. Physiologically and morphologically characterized neurones were mostly large pyramidal neurones that responded to more than one whisker and displayed transient-type responses. 3. In tangential sections, the apical dendrite of the HRP-filled neurone was followed from the soma level upward as it ascended through the barrelfield in layer 4. The cross-section of the apical dendrite was found in the periphery of the CO-stained barrel. Using the apical dendrite as a guide, the basal dendritic field of the layer 5b pyramidal neurone was aligned on the pattern of layer 4 barrels. The soma was seen to project basal dendrites in all directions, involving one or two neighbouring barrels/columns. 4. In sixteen neurones examined in tangential sections, a complete spatial tuning map constructed by measuring sensitivity of the neurone to different whiskers could be compared to the basal dendritic field in relation to the pattern of overlying layer 4 barrels. The mean receptive field size in terms of the number of effective whiskers was 5.8 whereas the mean dendritic field size in terms of the number of barrels/columns involved was 2.2. In addition to the well-documented role of intracortical connectivity in elaboration of multi-whisker receptor fields in the cortical neurones, the role played by direct inputs from multi-whisker thalamic ventrobasal neurones was discussed.

3,3'-Diaminobenzidine

Effects of vagal stimulation on cesium-induced early afterdepolarizations and ventricular arrhythmias in rabbits.

BACKGROUND: Previous evidence has shown that increased sympathetic tone enhances the cesium chloride (Cs)-induced early afterdepolarizations (EADs) and ventricular tachycardias (VTs). METHODS AND RESULTS: We assessed the effects of vagal stimulation on Cs-induced EADs and ventricular arrhythmias in the rabbit heart. Monophasic action potentials (MAPs) of the left ventricular endocardium were recorded simultaneously with surface ECG. Two protocols were used: 1) While in their intrinsic sinus rhythm, 11 rabbits were given three intravenous Cs injections (1 mM/kg) 20 minutes apart, and the effects of vagal stimulation on the ventricular arrhythmias thus induced were examined. 2) Under constant atrial pacing (cycle length, 250 msec), EAD amplitude was measured after Cs injection (1 mM/kg) without (five rabbits, control group) or with (four rabbits, vagal stimulation group) vagal stimulation. We observed the following. 1) Cs produced EADs and VTs of polymorphic (PVT) and monomorphic (MVT) types. During PVT, the take-off potential of repetitive premature action potentials in MAP recordings was about the same as the peak level of EADs, and during MVT, the take-off potential was the level of full repolarization. Vagal stimulation suppressed PVT but not MVT. Vagal stimulation after spontaneous termination of MVT restarted MVT of the same morphology at a rate much slower than the preceding sinus rate. 2) EAD amplitude was significantly smaller in the vagal stimulation group than in the control group. CONCLUSIONS: The results suggest that PVT originated from triggering by EADs, whereas MVT was of different origin, and that vagal stimulation suppressed PVT by decreasing the amplitude of EADs.

Action Potentials

[Studies on anti-nephritic effects of plant components (5). Effects of pherodendrin on original and crescentic-type anti-GBM nephritis in rats].

Effects of pherodendrin (OB-5) on anti-GBM nephritis were investigated. OB-5 (50 mg/kg/day, i.p.) prevented the urinary protein excretion in original and crescentic-type anti-GBM nephritis in rats. In addition, OB-5 also inhibited the elevation of serum creatinine, urea nitrogen and cholesterol contents in both models of nephritis. Histopathological observations indicated that OB-5 prevented the hypercellularity, crescent formation, adhesion and fibrinoid necrosis in the glomeruli of nephritic rats. OB-5 and cyclosporine A, a positive control drug, prevented the increase in the number of OX-1, CD8 and ED-1 positive cells in the glomeruli. These results indicated that OB-5 may be effective in human glomerulonephritis, and anti-nephritic mechanisms of OB-5 may be due to its inhibition of the activation of macrophages or cytotoxic T cells.

Animals

Studies on the antinephritic effect of plant components (4): Reduction of protein excretion by berberine and coptisine in rats with original-type anti-GBM nephritis.

The present study was conducted to investigate the antinephritic effects of berberine and coptisine, which are contained in Coptidis rhizoma, on original-type anti-GBM nephritis in rats. Berberine and coptisine at the doses of 0.5, 1.0 and 5.0 mg/kg/day, i.p. were effective in inhibiting urinary protein excretion, elevation of serum cholesterol and creatinine contents as well as glomerular histopathological changes. In addition, berberine at 20 mg/kg/day, p.o. also inhibited urinary protein excretion throughout the experimental periods. Berberine and coptisine inhibited platelet aggregation in both in vitro and in vivo assays, and berberine inhibited the decline of renal blood flow. Although berberine inhibited an increase in thromboxane B2 formation, it increased the formation of 6-keto-prostaglandin F1 alpha in platelets and isolated glomeruli. These results indicate that the antinephritic effects of berberine and coptisine may be partly due to antiplatelet action and improved renal hemodynamics via changing prostanoid synthesis.

6-Ketoprostaglandin F1 alpha

Preventive actions of N-(3-aminopropionyl)-L-histidinato zinc (Z-103) through increases in the activities of oxygen-derived free radical scavenging enzymes in the gastric mucosa on ethanol-induced gastric mucosal damage in rats.

Z-103 at 1 to 25 mg/kg, p.o. prevented 100% ethanol-induced gastric mucosal lesions in a dose-dependent manner. Z-103 at 3 to 25 mg/kg, p.o. significantly elevated gastric mucosal superoxide dismutase (SOD)-like activity 1 hr after its administration to normal rats. In addition, Z-103 at doses (10 and 25 mg/kg, p.o.) which prevented 100% ethanol-induced gastric lesion further increased gastric mucosal SOD-like and glutathione peroxidase (GSH-px) activities elevated by 60% ethanol. Z-103 (10 and 25 mg/kg) significantly inhibited the increase in thiobarbituric acid-reactive substances in gastric mucosa injured by 60% ethanol. The combination with cycloheximide, a protein synthesis inhibitor, completely abolished the prevention of 60% ethanol-induced gastric mucosal lesions and the elevation of both free radical scavenging enzyme activities in the mucosa by Z-103 (10 mg/kg, p.o.). These results suggest that Z-103 may partly protect rat gastric mucosa against ethanol-induced damage by scavenging oxygen-derived free radicals via increases in the synthesis of SOD-like and GSH-px enzymes in the mucosa.

Administration, Oral

Increased proportions of peripheral blood gamma delta T cells in patients with pulmonary tuberculosis.

There is a small population of peripheral T cells bearing the gamma delta T-cell receptor, which may be involved in the defense against invading microorganisms and tumor cells. The present study was designed to evaluate the levels of gamma delta T cells in patients with pulmonary tuberculosis, bacterial pneumonia, chronic lower respiratory tract infection, lung cancer, and normal control subjects with or without old tuberculous lesion. The results showed that only patients with tuberculosis had significantly increased proportions of peripheral blood gamma delta T cells. This study suggests that the increased proportions of gamma delta T cells in tuberculosis could be related to T-cell activation by Mycobacterium tuberculosis, although it remains to be investigated which components of mycobacteria are the major ligands for gamma delta T cells.

Adolescent

Interleukin 6 activity in pleural effusion. Its diagnostic value and thrombopoietic activity.

We measured interleukin 6 (IL-6) concentrations in the pleural fluid of various patients to determine its role in pathophysiology and diagnosis by using specific functional bioassay. IL-6 levels were significantly higher in exudate than in transudate (79.3 +/- 176.2 U/ml [n = 55] vs 1.7 +/- 1.8 U/ml [n = 12]; p < 0.01). Tuberculous effusion contained a significantly higher amount of IL-6 than malignant effusion (181.3 +/- 176.2 U/ml [n = 13] vs 29.4 +/- 71.5 U/ml [n = 29]; p < 0.005). Pleural IL-6 levels were invariably higher than serum IL-6 levels, and both were significantly correlated (n = 21, r = 0.632; p < 0.02). Pleural IL-6 levels were significantly correlated with lactate dehydrogenase (LDH) in pleural fluid (r = 0.392; p < 0.01), ratio of pleural/serum LDH (r = 0.571; p < 0.01), pleural adenosine deaminase activity (r = 0.599; p < 0.01), and serum C-reactive protein (r = 0.494; p < 0.01). Furthermore, IL-6 levels were significantly correlated with peripheral blood platelet counts (r = 0.447; p < 0.001). These results suggest that (1) IL-6 is produced locally in pleural space, (2) pleural IL-6 level is helpful for differential diagnosis, and (3) locally produced IL-6 could leak to circulation and cause systemic effects such as the induction of C-reactive protein and thrombocytosis.

Adenosine Deaminase

Mexiletine and disopyramide suppress ventricular premature contractions (VPC) irrespective of the relationship between the VPC and the underlying heart rate.

The effects of mexiletine (300 mg/day, 24 patients) and disopyramide (300 mg/day, 20 patients) on ventricular premature contractions (VPCs) were studied using a 24-hour ambulatory electrocardiogram. The VPC frequency was evaluated as a function of the underlying heart rate (HR). The VPC-HR correlation was classified into 2 major types, depending on whether the frequency of the VPC increased with the increased HR (positive type) or not (nonpositive type). The effects of the drugs were assessed based on the VPC-HR correlation and on the percent reduction of the VPC frequency. Mexiletine and disopyramide significantly decreased the frequency of the VPCs of both the positive and nonpositive types. Each drug was assumed to be effective when the percent reduction of the VPC frequency exceeded 70%. Mexiletine (300 mg/day) was 58.5% effective in positive type patients and 33.3% effective in nonpositive type patients, with a total efficacy of 45.8%. Disopyramide was effective in 50% of total cases with 44.4% in positive type patients and 54.5% in nonpositive type patients. However, the efficacy of these drugs on the 2 different types of VPCs was the same statistically. The findings strikingly contrasted those obtained with diltiazem and atenolol, which predominantly suppressed VPCs of the positive type which share similar characteristics with a triggered activity in vitro. We conclude that the mode of action of class I antiarrhythmics on the VPCs differs from that of class II or IV antiarrhythmics, as viewed from the VPC-HR relationship, and that the difference probably comes from the different arrhythmogenesis for positive and nonpositive types of VPCs, in addition to the different electrophysiological actions of mexiletine and disopyramide.

Cardiac Complexes, Premature

[Laboratory breeding of the red-backed vole (Clethrionomys rufocanus bedfordiae)].

Laboratory matings were attempted to establish breeding colonies of red-backed voles (Clethrionomys rufocanus bedformidae) as experimental animals. For these mating, 10 pairs of red-backed voles which were captured in the Tohbetsu region of Hokkaido, Japan and their litters were used. In the results for two years, 1987 to 1988, the rates of pregnancy, birth and weaning were 35.4%, 94.5% and 79.5%, respectively. The mean litter size was 5:1 +/- 1.6 with a range of 1 to 9. The mean gestation period was 20.0 +/- 0.7 days with a range of 18 to 22. These results suggest that planned production of red-backed voles in the laboratory is possible. To determine intraregional variations of red-backed voles with a view to the establishment of a strain by inbreeding, restriction patterns of mitochondrial DNAs using seven restriction endonucleases were compared. Four different patterns were obtained from wild red-backed voles used in the present study.

Animals

High-performance liquid chromatographic separation and spectral identification of the photoreaction products of methyl 5,8-epoxyretinoate.

Photoreaction of methyl 5,8-epoxyretinoate was investigated. Irradiation of methyl 5,8-epoxyretinoate in acetonitrile with a light from a high-pressure mercury lamp or a daylight fluorescent lamp afforded three new products, which were purified by high-performance liquid chromatography. They were characterized on the basis of spectroscopic data as 11-(Z), 13-(Z), and 11,13-di(Z) isomers, respectively.

Chromatography, High Pressure Liquid

[A study on relationship between personality and self-acceptance].

UNLABELLED: The purpose is to examine the relationship between self-acceptance and personalities developmentally, as for evaluative and affective dimensions. RESULTS: Males and females showed differences in the formation of adolescent self-acceptance. At junior high school level, the accepted personalities are not yet differentiated as for two dimensions in both males and females. In males, they are differentiated at senior high school, and above this level, they showed a linear increase in differentiation. Females showed emotional differentiation at junior high school, and behavioral differentiation at senior high school, and further emotional differentiation at college level. The transition of male is "from a few limited to diverse", while for females it is "from diverse to a few limited". As the traits to self-acceptance diversify, the self-acceptance score is high.

Adolescent

[Clinical study on cefprozil fine granules].

Cefprozil (CFPZ, BMY-28100), a new non-ester cephem, was administered to 15 pediatric patients with infectious diseases. The patients included 6 boys and 9 girls from 10 months to 11 years old and they were given oral doses of 18.5-41.7 mg/kg/day for 3 to 8 days. Clinical efficacies were excellent in 3 cases and good in 12 cases, hence the total efficacy rate was 100%. Eosinophilia occurred in 1 case as side effect of the drug, but no other side effects were not found during or after the treatment.

Administration, Oral