Search PubMed⌕ Search

Biomedical subjects

M Yasuda

Publications and source records attributed to M Yasuda.

At least 163 records · Page 9Linked to original sources
PubMed1998

Delusions of oral parasitosis.

1. The authors present a case of a 76-year-old man with delusional disorders, somatic type, who strongly believed that his mouth was infested with worms. 2. Such a case has not previously been described in the literature and the authors refer to the syndrome as delusions of oral parasitosis. 3. The authors examined the effect of pimozide, whose efficacy on delusional skin parasitosis has been proven. Taking the neuroleptic at a dose of 2 mg daily relieved the symptoms.

Aged↗
PubMed1998

Temporary scapho-trapezoidal joint fixation for Kienböck's disease in a 12-year-old girl: a case report.

Temporary scapho-trapezoidal joint fixation with Kirschner wires was performed for stage IIIB Kienböck's disease in a 12-year-old girl. Preoperative evaluation with radiographs and magnetic resonance imaging confirmed the diagnosis. After 4 months of fixation, wrist range of motion was improved and pain was decreased. Postoperative magnetic resonance imaging revealed revascularization and fracture healing. Temporary scapho-trapezoidal fixation may be useful in the treatment of selected cases of Kienböck's disease in children.

Bone Nails↗
PubMed1998

Diversity revealed by a novel family of cadherins expressed in neurons at a synaptic complex.

In mammals, neurons are highly differentiated and play distinctive functions even in the same brain region. We found a novel cadherin-related neuronal receptor (Cnr) gene family by studying Fyn-binding activity in mouse brain. CNR1 protein is located in the synaptic junction and forms a complex with Fyn. Sequence analysis of eight Cnr products of approximately 20 genes indicates that these comprise a novel cadherin family of the cadherin superfamily. The expression patterns of each member of this novel family were grossly similar to each other but restricted to subpopulations of neurons of the same type. The diversity of the Cnr family genes suggests that there are molecular mechanisms that govern highly differentiated neural networks in the mammalian CNS.

Animals↗
PubMed1998

Isoform-specific redistribution of calcineurin A alpha and A beta in the hippocampal CA1 region of gerbils after transient ischemia.

To investigate isoform-specific roles of Ca2+/calmodulin-dependent phosphatase [calcineurin (CaN)] in ischemia-induced cell death, we raised antibodies specific to CaN A alpha and CaN A beta and localized the CaN isoforms in the hippocampal CA1 region of Mongolian gerbils subjected to a 5-min occlusion of carotid arteries. In the nonischemic gerbil, immunoreactions of both isoforms were highly enriched in CA1 regions, especially in the cytoplasm and apical dendrites of CA1 pyramidal neurons. At 4-7 days after the induced ischemia, immunoreactivities of the CaN A alpha isoform in CA1 pyramidal cells were markedly reduced, whereas they were enhanced in the CA1 radiatum and oriens layers. In contrast, CaN A beta immunoreactivities were reduced in all layers of the ischemic CA1 region, whereas they were enhanced in activated astrocytes, colocalizing with glial fibrillary acidic protein. These findings suggest that up-regulation of CaN A alpha in afferent fibers in CA1 and up-regulation of CaN A beta in reactive astrocytes may be involved in neuronal reorganization after ischemic injury.

Animals↗
PubMed1998

Lack of association of apolipoprotein E epsilon4 allele dose with cerebral glucose metabolism in Alzheimer disease.

Parietal cerebral glucose metabolism is reduced before substantial impairments appeared in subjects carrying the apolipoprotein E (APOE) epsilon4 allele, but the effect of the APOE epsilon4 allele on cerebral metabolism in Alzheimer disease (AD) is still undetermined. To investigate the effect of the APOE epsilon4 allele on cerebral metabolism in AD, we examined regional cerebral glucose metabolism in 83 patients with AD by using 18F-fluorodeoxyglucose and positron emission tomography. Cerebral glucose metabolism in the fronto-parieto-temporal association and limbic cortices was significantly decreased in the AD patients compared with 26 age- and sex-matched normal controls. Regional cerebral glucose metabolic rate was not correlated significantly with the number of APOE epsilon4 alleles in any region, which was consistent even after controlling the effects of age, sex, and severity of dementia, and in a subgroup analysis of those aged between 60 and 75. These results supported the view that the APOE epsilon4 allele is not associated with specific deficits in brain metabolism in AD despite evidence of preclinical alterations.

Aged↗
PubMed1998

Serous borderline ovarian tumor with functioning stroma in a postmenopausal woman: immunohistochemical analysis of steroidogenic pathway.

An epithelial ovarian tumor with estrogenic manifestations (vaginal bleeding, vaginal softening) was encountered in a 70-year-old woman. The preoperative serum levels of estrone, estradiol, and testosterone were elevated. A right ovarian serous papillary tumor of borderline malignancy was removed and found to have a cellular, focally luteinized stroma. Steroidogenic enzymes, including 3beta-hydroxysteroid dehydrogenase and P450 cytochromes specific for cholesterol side-chain cleavage (P450scc), 17alpha-hydroxylation (P45017alpha), and aromatization (P450arom), were immunohistochemically demonstrated in the stromal cells. Immunohistochemical evaluation of these enzymes suggest significant functional differences among the enzymatically-activated stromal cells. That only rare stromal cells were immunoreactive for P450arom suggests that most of the testosterone synthesized in the tumor is extragonadally converted to estrogen, resulting in tumor-associated estrinism.

3-Hydroxysteroid Dehydrogenases↗
PubMed1998

Electrophysiological characteristics during slow pathway ablation of posterior atrioventricular junctional reentrant tachycardia.

The purpose of this study was to compare the electrophysiological characteristics of posterior and anterior atrioventricular junctional reentrant tachycardia (AVJRT) during radiofrequency (RF) catheter ablation of a slow pathway. Twenty-four patients with common AVJRT, including 4 posterior (P) and 20 anterior AVJRT (A) were studied. We analyzed the retrograde atrial activation sequence of junctional rhythm and the presence of transient HA block during slow pathway ablation. When HA block developed, the AH interval before ablation and immediately after the end of energy delivery was measured. Successful ablation sites were divided into three groups; high (H), middle (M), and low (L) from the His bundle to the floor of the coronary sinus orifice. The results were: (1) the number of successful ablation sites were H 0, M 1, L 3 in P and H 1, M 8, L 11 in A; (2) the HA interval during AVJRT in P was longer than that in A (109 +/- 48 ms vs 43 +/- 6 ms, P < 0.01); (3) the retrograde atrial activation sequence during junctional rhythm was strictly concordant with that during AVJRT in both groups, but HA block developed during slow pathway ablation more often in P than in A (100% vs 30%, P < 0.01); and (4) The AH interval did not lengthen after HA block developed in P. These data suggest that another pathway does exist from the AV node to the atrium in addition to anterograde fast pathway and slow pathway, and that this pathway is used as the retrograde limb of P.

Cardiac Pacing, Artificial↗
PubMed1998

Effect of radiofrequency catheter ablation on parasympathetic denervation: a comparison of three different ablation sites.

UNLABELLED: Radiofrequency (RF) catheter ablation of supraventricular tachycardias (SVT) has been shown to result in local parasympathetic denervation. The purpose of this study was to estimate the correlation between RF cumulative energy and parasympathetic denervation at three different ablation sites. METHODS: 45 patients who underwent RF ablation of 36 AV reentrant tachycardias and 9 AV nodal reentrant tachycardias were studied. Twenty patients had left free-wall accessory pathways (group L), 8 patients right free-wall accessory pathways (group R), and 17 patients septal accessory pathways (n = 8) or slow pathways (n = 9) (group S). Time and frequency domain analysis of heart rate variability on 24-hour ambulatory ECG recordings was performed before and after RF ablation. pNN50 and the high frequency (0.15 to 0.40 Hz, HF) component were measured to examine the effects on parasympathetic nerve activity. The values of delta pNN50 and delta HF were expressed as the percent change of pNN50 and HF that occurred after versus before RF ablation. RESULTS: Both pNN50 and HF significantly decreased after RF ablation in all three groups. In group S, there was a significant correlation between RF cumulative energy and delta pNN50 (r = 0.66, P < 0.01) or delta HF (r = 0.58, P < 0.05). In contrast, there was no correlation between RF cumulative energy and delta pNN50 or delta HF in either group L or group R. CONCLUSION: These data suggest that RF ablation produces parasympathetic denervation at all three sites along the mitral or tricuspid annulus and that parasympathetic fibers may be located predominantly in the septal area.

Adult↗
PubMed1998

Expression of type I and type III collagens during the course of dimethylnitrosamine-induced hepatic fibrosis in rats.

AIMS/BACKGROUND: We wished to clarify the mechanisms that account for the increase in hepatic collagen accumulation during hepatic fibrosis. METHODS: The gene expression of type I and type III procollagens and matrix metalloproteinase-1 (MMP-1) was measured by Northern blot analysis; immunolocalization of both types of collagen was estimated by indirect immunohistochemical assay; and the hepatic content of collagen and malondialdehyde (MDA), a product of lipid peroxidation, were assayed in hepatic fibrosis induced in rats with a single dose of dimethylnitrosamine (DMN). RESULTS: During the experimental period, more type I procollagen mRNA was found than type III procollagen mRNA. The immunoreactive intensity of type I collagen was greater in necrotic areas near central veins 3 days after DMN treatment than it was on day 9, whereas the type III collagen immunodeposition for the latter period of the hepatic fibrosis was stronger than it was on day 3. As compared with controls, hepatic collagen content increased significantly after 3 days and continued, increasing gradually, as did type I and III procollagen mRNA levels. On day 14, fibrosis was greatest and both types of procollagen gene expression were at their highest, and type I and III procollagen mRNA levels and hepatic collagen content increased as the dosage of DMN was raised. MMP-1 mRNA levels increased early in hepatic fibrogenesis, and increased on day 14 when DMN dosages were low. Hepatic MDA levels increased rapidly for 3 days after DMN treatment, remaining significantly higher than control values and showing a significant increase even in response to low DMN doses on day 14. CONCLUSIONS: Our results suggested that fibrotic liver collagen content may make its first notable increase due in part to the balance between type I collagen and MMP-1 expression rates. Also, lipid peroxidation may be important in the mechanism of hepatofibrogenesis.

Animals↗
PubMed1998

Alteration in the GyrA subunit of DNA gyrase and the ParC subunit of DNA topoisomerase IV in quinolone-resistant clinical isolates of Staphylococcus epidermidis.

We examined 22 clinical isolates of Staphylococcus epidermidis to analyze the association of alterations in GyrA and ParC with fluoroquinolone resistance. The simultaneous presence of GyrA and ParC alterations was associated with a high level of fluoroquinolone resistance in the clinical isolates of S. epidermidis.

4-Quinolones↗
PubMed1998

Alterations in the GyrA subunit of DNA gyrase and the ParC subunit of DNA topoisomerase IV associated with quinolone resistance in Enterococcus faecalis.

The gyrA and parC genes of 31 clinical isolates of Enterococcus faecalis, including fluoroquinolone-resistant isolates, were partially sequenced and analyzed for target alterations. Topoisomerase IV may be a primary target in E. faecalis, but high-level fluoroquinolone resistance was associated with simultaneous alterations in both GyrA and ParC.

4-Quinolones↗
PubMed1998

Suppressive effect of oestradiol on chemical hepatocarcinogenesis in rats.

AIMS: To examine the effects of oestradiol and testosterone on the early carcinogenic changes expressed in rat liver from the diethylnitrosamine (DEN), 2-acetylaminofluorene (AAF), partial hepatectomy (PH) model of hepatocarcinogenesis. METHODS: Preneoplastic liver lesions were evaluated using immunohistochemical analysis of glutathione-S-transferase placental form (GST-P) expression; oestrogen and androgen receptor levels were measured by radioimmunoassay. RESULTS: Oestradiol administration to non-castrated DEN-AAF-PH treated males resulted in a decrease in the area of GST-P positive foci, while testosterone increased the serum oestradiol level and reduced the area. In males, castration alone and castration with oestradiol replacement significantly reduced the GST-P positive area, and increased the hepatic oestrogen receptor level. In DEN-AAF-PH treated females, castration with testosterone replacement was associated with a significant increase in the GST-P positive area and the hepatic androgen receptor level. CONCLUSION: These findings suggest that exogenous and endogenous oestradiol can suppress chemical hepatocarcinogenesis. It appears that oestrogen receptors may be involved in the inhibition of malignant transformation of preneoplastic liver cells, while androgens and androgen receptors are involved in hepatocarcinogenesis.

2-Acetylaminofluorene↗
PubMed1998

Factors associated with psychotic symptoms in Alzheimer's disease.

OBJECTIVES: Many clinical and biological factors have been reported to be associated with the presence of psychosis in patients with Alzheimer's disease, although the associations were variable. The aim of this study was to clarify factors associated with the presence of psychosis in patients with Alzheimer's disease. METHODS: Psychiatric functioning was studied in 228 patients with Alzheimer's disease based on the results of the behavioural pathology in Alzheimer's disease rating scale or the neuropsychiatric inventory. The effects of sex, education level, age, duration of illness, cognitive function, and apolipoprotein E genotype were investigated for dichotomous psychotic status with a multiple logistic regression analysis. RESULTS: Of the 228 patients with Alzheimer's disease, 118 (51.8%) showed evidence of delusions or hallucinations. Of these, 94 had delusions only, three had hallucinations only, and 21 had both. Older age, female sex, longer duration of illness, and more severe cognitive impairment were the factors independently associated with the presence of psychosis. The presence of psychosis was not significantly related to either educational level or apolipoprotein E genotype. CONCLUSIONS: Age, sex, and severity of illness were independent factors associated with the presence of psychosis in patients with Alzheimer's disease. The reason why some patients with Alzheimer's disease develop psychosis remains unclear. There may be distinctive subtypes of Alzheimer's disease or the presence of individual factors which affect the development of psychosis.

Aged↗
PubMed1998

Apolipoprotein E epsilon 4 allele and whole brain atrophy in late-onset Alzheimer's disease.

OBJECTIVE: Diffuse brain atrophy is one of the gross pathological features of Alzheimer's disease and is a result of degenerative changes. The epsilon 4 allele of apolipoprotein E (APOE) is a risk factor or susceptibility gene in late-onset sporadic Alzheimer's disease and may influence the pathological changes associated with the disease. The aim of this study was to examine the relationship between the APOE epsilon 4 allele and whole brain atrophy. METHOD: Whole brain volume was quantified by using high-resolution magnetic resonance imaging and the computerized brain segmentation technique in 178 patients with late-onset sporadic Alzheimer's disease who carried no APOE epsilon 4 alleles (N = 62), one epsilon 4 allele (N = 93), or two (N = 23) and had comparable clinical severity of dementia. RESULTS: An apparent positive correlation was found between normalized whole brain volume (relative to total intracranial volume) and number of APOE epsilon 4 alleles; i.e., patients carrying two APOE epsilon 4 alleles had the least brain atrophy. This association between the APOE epsilon 4 allele and brain volume was similar in women and men and was independent of age, level of education, duration of illness since symptom onset, and severity of dementia. CONCLUSIONS: The results indicate that cognitive dysfunction progresses before severe brain atrophy develops in patients carrying the APOE epsilon 4 allele and suggest that an APOE epsilon 4-allele-related mechanism that affects neuronal function before a decrement in brain matter is involved in the development of dementia.

Aged↗
PubMed1998

Therapeutic usefulness of wild-type p53 gene introduction in a p53-null anaplastic thyroid carcinoma cell line.

Anaplastic thyroid carcinomas very often harbor the mutations in the tumor suppressor gene p53. We have previously shown that wild-type (wt) p53 gene introduction led to cell growth arrest, but not apoptosis, in p53-null anaplastic thyroid carcinoma cells. The present studies were designed to evaluate other therapeutic effects of wt-p53 gene introduction on p53-null thyroid carcinoma cells, as chemo- and radiosensitization and inhibition of angiogenesis have also been described recently as additional therapeutic advantages of wt-p53 gene introduction in tumor cells with p53 mutations. A p53-null anaplastic thyroid carcinoma cell line, FRO, and a FRO subline stably expressing a temperature-sensitive (ts) mutant of p53 (p53Val138), tsFRO, were used. ts-p53 functions as mutant and wt at nonpermissive (37 C) and permissive (32 C) temperatures, respectively. tsFRO showed a prolonged cell doubling time compared to parental FRO when cultured at 32 C, but the cell growth rate was similar between FRO and tsFRO at 37 C. The cytotoxic and clonogenic assays demonstrated that although the sensitivity to three different anticancer agents (cisplatin, 5-fluorocytosine, and doxorubicin) was unaltered, radiosensitivity was enhanced in tsFRO compared to FRO at 32 C. Unexpectedly, in studies on angiogenesis, expression levels of vascular endothelial growth factor (an angiogenic factor) messenger ribonucleic acid were similar between FRO and tsFRO, and thrombospondin-1 (an antiangiogenic factor) messenger ribonucleic acid and protein levels were about 2.5-fold lower in tsFRO than FRO at 32 C, although any difference could not be detected in their ability to inhibit in vitro angiogenesis with the culture medium conditioned by tsFRO and FRO at 32 C. These results suggest that p53-defective thyroid carcinomas may benefit from the combination of p53 gene therapy and radiotherapy. However, further study will be necessary to clarify the pathological significance of thrombospondin-1 in angiogenesis and thyroid tumor growth.

Antimetabolites, Antineoplastic↗
PubMed1998

A specific and rapid method for determination of adenosine 3'-monophosphate (3'-AMP) content and 3'-AMP forming enzyme activity in rat liver mitochondria, using reversed-phase HPLC with fluorescence detection.

To study the physiological significance of adenosine 3'-monophosphate (3'-AMP), an intracellular P-site inhibitor of adenylate cyclase, in rat liver mitochondria, a specific, rapid and reliable assay method for determination of 3'-AMP and the activity of its forming enzyme is required. 3'-AMP in rat liver was determined to be ca. 23+/-7 nmol/g wet weight, but no 2-deoxy-3'-AMP, another P-site inhibitor of adenylate cyclase, was detected, even when using a reversed-phase HPLC column with a fluorescent-reaction, as established in this study. By using the optimized assay method developed here, 3'-AMP forming enzyme activity in rat crude mitochondrial extract was found to be enhanced by EDTA and inhibited by p-chloromercurybenzoate. The optimum pH was ca. 5.8 and no divalent cation was required for activity. From these results, 3'-AMP forming enzyme(s) in rat liver mitochondria could be classified as acid exoribonuclease, which mainly existed in an active form. The results obtained in this study will help to gain more insight into the physiological roles of 3'-AMP in living systems.

Adenosine Monophosphate↗