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Biomedical subjects

Y Oishi

Publications and source records attributed to Y Oishi.

At least 91 records · Page 5Linked to original sources
PubMed1996

[Diffuse proliferative lupus nephritis in a patient with ulcerative colitis].

A 31 year-old man treated with sulfasalazine for ulcerative colitis, developed nephrotic syndrome, photosensitivity, alopecia, lymphopenia and hypocomplementemia. Anti-nuclear antibody (speckled) and antibodies to single-stranded DNA and SS-A were positive, while those against native DNA and histon were negative. Renal biopsy revealed diffuse proliferative lupus nephritis. His nephrotic syndrome partially improved with corticosteroid therapy combined with cessation of sulfasalazine. His complement level became normal, however it decreased again during the gradual reduction of corticosteroid dosage. In conclusion, we diagnosed the patient's illness as an idiopathic syntemic lupus erythematosus rather than sulfasalazine-induced lupus.

Adult↗
PubMed1995

Effects of hypobaric hypoxia on histochemical fibre-type composition and myosin heavy chain isoform component in the rat soleus muscle.

Histochemical fibre-type composition and myosin heavy chain isoform component in the soleus muscle were studied in normoxic rats at postnatal ages of 5, 10, 15, and 20 weeks and in rats exposed to hypobaric hypoxia (460 torr) for 5 weeks from postnatal ages of 5, 10, and 15 weeks. The increase in the percentage of type I fibres and the concomitant decrease in that of type IIa fibres in the soleus muscle of normoxic rats were observed until 15 weeks of age. On the other hand, no change in the fibre-type composition of the muscle during postnatal development was observed in hypoxic rats, irrespective of the age at which they were exposed to hypoxia. The changes in the myosin heavy chain isoform component (MHC I and MHC IIa) of the muscle during postnatal development and by hypoxia corresponded well with those in the muscle fibre-type composition. It is concluded that hypobaric hypoxia inhibits the growth-related shift of muscle fibre-types from type IIa to type I and of myosin heavy chain isoforms from MHC IIa to MHC I in the rat soleus muscle, and that there are no changes in the muscle fibre-type composition or the myosin heavy chain isoform component caused by hypoxia after the shifts in these parameters which occur during postnatal development are completed.

Aging↗
PubMed1995

[Quinolone-resistant mutations in Neisseria gonorrhoeae].

For 10 strains of Neisseria gonorrhoeae exhibiting decreased susceptibility to new quinolones (MIC, > or = 0.1 microgram/ml) isolated and preserved from patients with gonococcal urethritis during the period from February 1991 through January 1992. We investigated the mechanisms for development of resistance to new quinolones. After selecting 3 PCG-sensitive and new quinolone-resistant strains from among these strains, we first carried out transformation experiments of N. gonorrhoeae using a plasmid carrying the E. coli gyrA gene. We then determined the base sequence on the N. gonorrhoeae gyrA gene by PCR method. Of the 3 strains in which transformation experiments were carried out, 2 strains yielded transformants, one of which was 8 times more sensitive to norfloxacin (NFLX) than the original strain, and it was assumed that this strain has a mutation in the gyrA gene. In our study of the base sequence on the N. gonorrhoeae gyrA gene using the PCR method, both strains had the mutation of Ser 83 (TCC)-->Phe (TTC), and in addition to this mutation of Ser-->Phe, one other strain had the mutation of Asp-87 (GAC)-->Gly (GGC). This type of mutation of quinolone-resistant N. gonorrhoeae on the gyrA gene has high homology with the mutations reported for Escherichia coli and other strains and there appears to be a close correlation between the increasing frequency of use of the new quinolones in this country and the spread of such resistant strains of N. gonorrhoeae.

Drug Resistance, Microbial↗
PubMed1995

Lower number and thinner myelin of large myelinated fibers in human cervical compression radiculopathy.

The authors conducted a morphometric investigation of the histopathological alterations in myelinated fibers (MFs) of the nerve roots of C-6, which showed macroscopic indentation, presumably due to cervical spondylotic radiculopathy. In six cadavers, designated as the radiculopathy group, in which the nerve roots of C-6 showed indentation due to compression on one side (indented side) and the remaining nerve roots (normal side) showed a normal appearance macroscopically, morphometric findings of the nerve roots and the MFs on both the indented and normal sides were evaluated and subjected to blind comparison. Seven cadavers with normal-appearing C-6 nerve roots served as controls. In the control group, there were no differences in the morphometric parameters: that is, total transverse fascicular area, total number of small and large MFs, and relationship between myelin thickness and the radius of the axon between the right and left sides in either the ventral or dorsal roots. There was no evidence found of axonal degeneration, ongoing demyelination, or loss of MFs in either the ventral or dorsal roots in the radiculopathy group on the indented side. However, there were significantly lower numbers of large MFs per root and significantly thinner myelin sheaths relative to axon size on the indented side compared with those on the normal side in both the ventral and dorsal roots. These findings are characteristic alterations of the MFs produced by chronic low-grade compression.

Aged↗
PubMed1994

Changes in fibre-type composition and myosin heavy-chain IId isoform in rat soleus muscle during recovery period after hindlimb suspension.

We examined the changes in myosin heavy-chain (HC) isoforms and fibre-type composition in rat soleus muscle using both myosin adenosine triphosphatase staining and sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE) analyses during the recovery period after 4 weeks of hindlimb suspension. Although there was no change in type IIc fibres after the suspension, an increase in this type of fibres was observed during the 1- to 4-week recovery period. The increase in type IIc fibres was considered to be due to a shift from type IIa to IIc fibres. The SDS-PAGE analysis revealed the presence of the HC IId isoform, which was not observed in the control muscle, after a 4-week hindlimb suspension. The HC IId isoform gradually decreased over 3 weeks of recovery and disappeared in the 4th week of recovery after the suspension. These results suggest that the hypogravity conditions induced by hindlimb suspension stimulated the synthesis of the HC IId isoform, whereas an increase in mechanical load to the muscle accelerated the degradation of the HC IId isoform and the synthesis of type IIc fibres during the recovery period after hindlimb suspension.

Animals↗
PubMed1994

Decreased collagenase expression in cultured systemic sclerosis fibroblasts.

One cause of the excessive deposition of collagen in systemic sclerosis is thought to be abnormal functioning of fibroblasts. The purpose of this study is to determine whether there is decreased expression of collagenase in systemic sclerosis fibroblasts. In this study, we analyzed collagen and collagenase expression in dermal fibroblasts derived from eight patients with systemic sclerosis and compared the findings with those from nine sex- and age-matched healthy subjects. Increased collagen synthesis accompanying enhanced mRNA levels was observed in two of eight strains, whereas all eight strains showed remarkable decreases in collagenase activity and production. There were no differences in the levels of collagenase mRNA between the systemic sclerosis strains and the normal strains. Results suggest that decreased collagenase expression is a characteristic of systemic sclerosis fibroblasts, and both increased collagen expression and decreased collagenase expression in systemic sclerosis fibroblasts may result in the excessive accumulation of collagen in patients with systemic sclerosis. It is also suggested that decreased collagenase expression is altered at translational and/or post-translational levels.

Adult↗
PubMed1994

Morphogenesis of esophageal carcinoma induced by N-methyl-N'-nitro-N-nitrosoguanidine in the house musk shrew, Suncus murinus (Insectivora).

The histological changes occurring in the esophageal mucosa of shrews (Suncus murinus) after N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) treatment were investigated sequentially. Six-week-old female shrews were given a 50 micrograms/ml MNNG solution as drinking water for 30 weeks, and 5 selected at random were killed at 10 and 20 weeks of age, and thereafter at 5-week intervals until 45 weeks of age. Controls were killed at 45 weeks of age. The MNNG-induced esophageal lesion in shrews began from basal cell hyperplasia at 20 weeks of age, followed by dysplasia occurring at 25 weeks of age, then progressed toward intraepithelial carcinoma to invasive squamous cell carcinoma at 35 weeks of age. Apparent sequential dysplasia-carcinoma transition was seen. Papillomas were seen from 25 weeks of age but there was no evidence of papilloma-carcinoma sequence. Five MNNG-untreated shrews killed at the end of the experiment were free of esophageal tumors.

Animals↗
PubMed1994

[Analysis of computed X-ray tomography of the brain in incontinence patients with senile dementia. Relationship between circulatory defect of the brain, brain atrophy and urinary incontinence].

To evaluate the condition of incontinence in patients with senile dementia, we performed computed tomography X-rays to the brain and analyzed the relationship among the circulatory defect of the brain, the brain atrophy and the degree of incontinence. There were 92 patients subjected to this study who were hospitalised due to senile dementia; 74 patients had vascular dementia, 10 patients had senile dementia of Alzheimer type, and 8 patients had the mixed type. (age ranged: 54-95 years; mean: 80.3 years). The degree of incontinence in these patients varied as follows: 18 patients with continence, 16 patients with moderate incontinence, 58 patients with total incontinence. The diagnosis of circulatory defect of the brain was based on computed tomography observation of periventricular lucency (P.V.L.), and the degree of brain atrophy was evaluated based on 4 criteria: the Lateral body ratio, the Huckman number, the Evans ratio, and the enlargement of the subarachnoid space. Among the 92 patients, P.V.L. was present in 31 patients, among them 27 patients suffered from incontinence. There was a significant correlation between P.V.L. and incontinence (p < 0.001). As the incontinence progressively worsened (Continence, Moderate incontinence Total incontinence), the lateral body ratio increased to 24.8, 27.8, 28.6, (p < 0.05). The Huckman number also increased to 18.3, 19.3, 21.3, (p < 0.01), and the evans ratio likewise 29.9, 32.3, 33.7 (p < 0.01). The enlargement of the subarachnoid space was also correlated with the severity of incontinence. We conclude that urinary incontinence originating from senile dementia is connected to brain atrophy and is strongly influenced by the circulatory disorders of the brain.

Aged↗
PubMed1993

Cellular proliferation in the anterior pituitary gland of normal adult rats: influences of sex, estrous cycle, and circadian change.

Proliferative activity of the anterior pituitary gland in 10 week-old male and female rats under normal conditions was investigated by counting mitotic figures and using single and double immunostaining of 5-bromo-2'-deoxyuridine (BrdU), proliferating cell nuclear antigen (PCNA), and six pituitary hormones. To determine which proliferative changes depend on the estrous cycle and circadian changes, respectively, six groups of female and two groups of male rats were studied at various times of day. Additionally, BrdU-incorporated cells were further classified by the six types of hormones they contained, or as immunonegative cells. Cell proliferative activity in the females fluctuated drastically with the highest activity in estrus and the lowest in diestrus. In the males, proliferative activity was at a relatively low level, and was similar to that in females in proestrus or early estrus, with the greater activity at night. Identified by their pituitary hormones, the distribution of the proliferating cells was almost the same in each sex, with prolactin (PRL) cells accounting for the highest proportion, followed by growth hormone (GH) cells, and adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), follicle stimulating hormone (FSH), and thyroid stimulating hormone (TSH) cells. These percentages agreed well with previously reported levels of cell types among all pituitary cells of the rat. It is therefore suggested that the life span and cycle of rat pituitary cells does not differ among cell types. In another test, male and female rats were given BrdU continuously via an osmotic pump for 8 days to compare cell proliferative activity between sexes, exclusive of the influence of estrous cycle and circadian changes. In this way, we were able to demonstrate that the cumulative incorporation of BrdU in females was consistently twice as high as in males over a constant period of time, and to conclude that cell renewal occurs at a doubled rate in the pituitary of female rat.

Animals↗
PubMed1993

Relationship between myosin heavy chain IId isoform and fibre types in soleus muscle of the rat after hindlimb suspension.

The relationship between the myosin heavy chain (HC) IId isoform and histochemically defined fibre types was investigated in the rat soleus muscle after hindlimb suspension. After 4 weeks of suspension, right and left muscles were removed and fibre type composition and total fibre number were examined by histochemical myosin adenosine triphosphatase staining sections. Myosin HC isoforms were analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis. After the suspension, there was a significant decrease in the percentage of type I fibres and a concomitant increase in that of type IIa fibres. However, the total number of fibres was not affected by suspension. The synthesis of HC IId isoform, which was not found in the control, and the decrease in the ratio of slow type myosin heavy chain isoform (HC I) were observed after suspension. These results would may suggest that the change of fibre type composition was caused by a shift from type I to IIa fibres after suspension. Furthermore, it could be suggested that the synthesis of HC IId isoform occurred during the stage of type shift from type I to IIa fibres.

Animals↗
PubMed1993

The high incidence of atrial thrombosis in mice given doxorubicin.

Doxorubicin (DX)-treated mice represent an animal model for studying new drugs for heart disease. Coincidentally, in the collection of damaged myocardial tissue, thrombosis was detected in the atrium. The incidence reached 75% in mice given 4 mg/kg DX iv 10 times. They were white thrombi consisting of the fibrin, platelets, and neutrophils. Cardiac muscle damage was more prominent in the atria than in the ventricles. Light microscopically, vacuolization and degeneration of atrial myocytes and interstitial inflammatory cell infiltration were observed. Electron microscopy revealed dilatation of the sarcoplasmic reticulum and an increase in number of normal and/or degenerate mitochondria. Inflammation extended from the cardiac muscle to the endocardium. The cause of atrial thrombosis in DX-treated mice is unknown but may relate to endocardial damage and changes of blood flow in the atrium secondary to cardiac muscle damage. DX-treated mice could serve as an experimental animal model for the evaluation of efficacy and toxicity of antithrombotic or antiplatelet drugs.

Animals↗
PubMed1993

Effects of hydrochloric acid on the development of enterochromaffin-like (ECL) cell hyperplasia in the rat stomach induced by omeprazole.

In the present study, gastric pH was lowered by hydrochloric acid to investigate whether the cause of enterochromaffin-like (ECL) cell hyperplasia was due to the inhibition of acid secretion by omeprazole or due to the direct action of the drug. Omeprazole was given to female Crj:CD (SD) rats in a daily oral dose of 2 or 8 mg/kg for 13 weeks, and 20 ml/kg of 0.12 N HCl was further given orally to the animals 3 and 6 hours after each dosing. The animals were killed at the end of the dosing period, and the stomach was removed and weighed. The thickness of the gastric wall was measured and ECL cell count and area rate of the cells were calculated with an image analyzer. There were no effects of the treatment with HCl on stomach weight or thickness of the gastric wall, but ECL cell count and area rate of the cells decreased markedly by the treatment with HCl. Therefore, the cause of gastric ECL cell hyperplasia induced by omeprazole was suggested to be sustained high gastric pH levels.

Animals↗
PubMed1992

Surgical excision of hemophilic pseudotumor of the ilium.

The iliac hemophilic pseudotumor is a rare complication of hemophilia occurring in 1-2% of patients with Factor VIII or Factor IX deficiency. It is frequently disabling and life threatening. This report presents a comparative study of postoperative results of two cases of hemophilic pseudotumor of ilium. One patient undergoing partial resection showed a favorable postoperative course, whereas the patient with complete resection of the pseudotumor died of postoperative bleeding and sepsis. Studies on the postoperative results of these two cases indicate that careful preoperative consideration of tumor size and degree of infiltration is of the utmost importance in operative management. Early excision of tumors eliminates the possibility of endogenous infection. Even partial resection of huge tumors, leaving the lateral wall intact for compression, can promote recovery of functions.

Angiography↗
PubMed1992

[Countermeasures for urinary incontinence in patients with senile dementia: correlation between urinary incontinence severity, senile dementia severity, and activity of daily living].

The actual conditions of urinary incontinence in 101 patients with senile dementia (23 men and 78 women, average age 80 years) and their urinary control was studied. The three categories of 1) dementia severity, 2) activity of daily living and 3) degree of urinary incontinence, were each divided into five grades and the patients were evaluated accordingly. The correlation among the grades was studied. Of the 101 patients, 87 had urinary incontinence. These 87 were further subdivided into two groups: an ambulatory patient group (25) in which the patients could manage their own daily activity, and the bedridden group (62). The countermeasures for the first group of patients were, usage of a portable chamber pot for 6 patients and induced urination in 5. An anticholinergic agent was administered to 47 of the bedridden patients. The condition of urinary incontinence was reevaluated in both groups 4 weeks later. A high degree of correlation was observed among the grades of dementia severity, activity of daily living and urinary incontinence severity. After the countermeasures taken, improvement in urinary incontinence was observed in the 6 patients who used a portable chamber pot, and in the 5 patients who were subjected to induced urination. No improvement was seen in urinary incontinence in the bedridden patients who were treated with an anticholinergic agent. In conclusion, countermeasures for urinary incontinence in senile dementia should be indicated primarily for patients who can manage their own daily activity.

Activities of Daily Living↗
PubMed1991

Induction of tumors in the Japanese house musk shrew, Suncus murinus (Insectivora), by dimethylbenz[a]anthracene.

The carcinogenic effect of 7,12-dimethylbenz[a]anthracene (DMBA) was examined in the virgin female Japanese house musk shrew, Suncus murinus (family: Soricidae, order: Insectivora). Leukemia, musk gland tumors, pilosebaceous tumors and sarcomas were induced in the DMBA-treated shrews, whereas none of the controls developed any tumors up to 50 weeks of age. DMBA emulsion was administered i.p. at a dose of 1.25 or 2.5 mg once a week, with either four or eight doses being given from 8 weeks of age. Leukemia developed in 100% (9/9), 50% (5/10), 56% (5/9) and 0% (0/10) of the animals treated with a total dose of 20 mg (8 x 2.5 mg), 10 mg (8 x 1.25 mg), 10 mg (4 x 2.5 mg) and 5 mg (4 x 1.25 mg) of DMBA respectively. Leukemia was of the lymphatic and/or mast cell type, and the spleen was the organ invariably involved. A dose-dependent effect of DMBA was not observed for pilosebaceous and musk gland tumors. When 1 mg of DMBA powder was dusted into the subcutaneous tissue at 4 weeks of age, sarcomas developed at the dusted site (69%; 9/13).

9,10-Dimethyl-1,2-benzanthracene↗