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Biomedical subjects

H Yasuda

Publications and source records attributed to H Yasuda.

At least 253 records · Page 14Linked to original sources
PubMed1997

Axonal contact regulates expression of alpha2 and beta2 isoforms of Na+, K+-ATPase in Schwann cells: adhesion molecules and nerve regeneration.

Three isoforms of catalytic alpha subunits and two isoforms of beta subunits of Na+,K+-ATPase were detected in rat sciatic nerves by western blotting. Unlike the enzyme in brain, sciatic nerve Na+,K+-ATPase was highly resistant to ouabain. The ouabain-resistant alpha1 isoform was demonstrated to be the predominant form in rat intact sciatic nerve by quantitative densitometric analysis and is mainly responsible for sciatic nerve Na+,K+-ATPase activity. After sciatic nerve injury, the alpha3 and beta1 isoforms completely disappeared from the distal segment owing to Wallerian degeneration. In contrast, alpha2 and beta2 isoform expression and Na+,K+-ATPase activity sensitive to pyrithiamine (a specific inhibitor of the alpha2 isoform) were markedly increased in Schwann cells in the distal segment of the injured sciatic nerve. These latter levels returned to baseline with nerve regeneration. Our results suggest that alpha3 and beta1 isoforms are exclusive for the axon and alpha2 and beta2 isoforms are exclusive for the Schwann cell, although axonal contact regulates alpha2 and beta2 isoform expressions. Because the beta2 isoform of Na+,K+-ATPase is known as an adhesion molecule on glia (AMOG), increased expression of AMOG/beta2 on Schwann cells in the segment distal to sciatic nerve injury suggests that AMOG/beta2 may act as an adhesion molecule in peripheral nerve regeneration.

Animals↗
PubMed1997

Multiple endocrine neoplasia type 1 presented with manic-depressive disorder: a case report with an identified MEN1 gene mutation.

We report a case of multiple endocrine neoplasia type 1 who had repeated hypoglycemic episodes and had previously been diagnosed with bipolar manic-depressive disorder. The patient had a positive family history of multiple endocrine neoplasia type 1 and had multiple pancreatic endocrine tumors, hyperparathyroidism and possibly a pituitary tumor. The pancreatic tumors were resected by subtotal pancreatectomy and examined by histochemical staining and gene analysis. The tumor cells were positive for immunoreactive insulin and glucagon. A microsatellite polymorphism analysis revealed loss of heterozygosity on 11q13 in the tumors. By polymerase chain reaction-based nucleotide sequencing, we identified a germline mutation 483del2 of the MEN1 gene in the normal pancreatic tissue of the patient. This mutation causes a shift of the reading frame of menin mRNA at codon 125. It seems that the wild type allele of the MEN1 gene had been lost in the tumor cells whereas the mutant allele remained intact. This is the first identified MEN1 gene mutation in Japanese families and is different from all MEN1 gene mutations reported previously.

Adult↗
PubMed1997

A case of pseudovascular adenoid squamous cell carcinoma of the skin with spindle cell pattern.

We report a case of pseudovascular adenoid squamous cell carcinoma which was in the form of a dome-shaped, cherry red tumor on the right cheek of an 86-year-old Japanese woman. Histologically, two types of atypical cells were identified; round cells in the upper part and spindle cells in the lower part. In the upper part, inter-anastomosing sinusoid-like pseudolumina were observed between the cords of the tumor cells. Immunohistochemically, the tumor cells did not express Factor VIII-related and CD34 antigens or bind Ulex europaes I agglutinin, except for only one anti-cytokeratin antibody. Ultrastructurally, the tumor cells contained tonofilaments and desmosomes and represented acantholysis. From the electron microscopy, possible role of capillary hyperpermeability on the acantholytic process of the neoplastic cells was suggested.

Aged↗
PubMed1997

A unique case of squamous cell carcinoma showing adenocarcinomatous features with focal apocrine differentiation.

We report an 85-year-old man with squamous cell carcinoma on the right pinna. Two years after the excision of the lesion, metastatic foci were found extending from the right retromandibular to the mastoid region and into the parapharyngeal space. Histopathologically, the primary tumor showed interconnecting nests of atypical cells invading into the dermis from multiple epidermal and infundibular foci. The tumor had both squamous and glandular differentiation. A peculiar finding was the presence of decapitation secretion in the glandular foci. To our knowledge, definite apocrine differentiation in squamous cell carcinoma has not previously been reported.

Adenocarcinoma↗
PubMed1997

Germline mutations of the MEN1 gene in Japanese kindred with multiple endocrine neoplasia type 1.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant familial cancer syndrome. The responsible gene MEN1 has recently been isolated, and its germline mutations have been identified in affected individuals in the United States, Canada and Europe. We screened for MEN1 mutations by direct nucleotide sequencing of all protein-coding regions, and identified five distinct germline mutations in five among six Japanese kindreds with familial MEN1 or familial hyperparathyroidism. The mutations were dispersed across the gene. These findings suggest that, because of the absence of an obvious founder effect, the entire MEN1 gene region should be examined for germline mutations in the probands of MEN1 and related syndromes in Japanese families.

DNA, Neoplasm↗
PubMed1997

Deleted form of hepatocyte growth factor (dHGF) increases the number of platelets in rats with liver cirrhosis.

The effect of the deleted form of hepatocyte growth factor (dHGF) on thrombopoiesis was studied in rats. When normal rats were injected with dHGF (0.5 mg/kg i.v. twice a day), the number of platelets increased to about 1.5-fold the initial level. In addition, the treatment with dHGF (0.5 mg/kg i.v. twice daily) significantly increased the number of platelets in rats with liver cirrhosis induced by carbon tetrachloride and phenobarbital. When dHGF was given to rats at a dose of 0.05 or 0.5 mg/kg from the beginning of the induction of dimethylnitrosamine liver cirrhosis to day 28, dHGF dose-dependently ameliorated thrombocytopenia and completely prevented it at a dose of 0.5 mg/kg. These results indicate that dHGF may be applicable to the treatment of thrombocytopenia associated with liver cirrhosis.

Animals↗
PubMed1997

In vitro and in vivo antibacterial activities of CS-834, a novel oral carbapenem.

CS-834 is a novel oral carbapenem antibiotic. This compound is an ester-type prodrug of the active metabolite R-95867. The antibacterial activity of R-95867 was tested against 1,323 clinical isolates of 35 species and was compared with those of oral cephems, i.e., cefteram, cefpodoxime, cefdinir, and cefditoren, and that of a parenteral carbapenem, imipenem. R-95867 exhibited a broad spectrum of activity covering both gram-positive and -negative aerobes and anaerobes. Its activity was superior to those of the other compounds tested against most of the bacterial species tested. R-95867 showed potent antibacterial activity against clinically significant pathogens: methicillin-susceptible Staphylococcus aureus including ofloxacin-resistant strains, Streptococcus pneumoniae including penicillin-resistant strains, Clostridium perfringens, Neisseria spp., Moraxella catarrhalis, most members of the family Enterobacteriaceae, and Haemophilus influenzae (MIC at which 90% of strains are inhibited, < or =0.006 to 0.78 microg/ml). R-95867 was quite stable to hydrolysis by most of the beta-lactamases tested except the metallo-beta-lactamases from Stenotrophomonas maltophilia and Bacteroides fragilis. R-95867 showed potent bactericidal activity against S. aureus and Escherichia coli. Penicillin-binding proteins 1 and 4 of S. aureus and 1Bs, 2, 3, and 4 of E. coli had high affinities for R-95867. The in vivo efficacy of CS-834 was evaluated in murine systemic infections caused by 16 strains of gram-positive and -negative pathogens. The efficacy of CS-834 was in many cases superior to those of cefteram pivoxil, cefpodoxime proxetil, cefdinir, and cefditoren pivoxil, especially against infections caused by S. aureus, penicillin-resistant S. pneumoniae, E. coli, Citrobacter freundii, and Proteus vulgaris. Among the drugs tested, CS-834 showed the highest efficacy against experimental pneumonia in mice caused by penicillin-resistant S. pneumoniae.

Administration, Oral↗
PubMed1997

Lack of association between the Trp64 Arg mutation in the beta 3-adrenergic receptor gene and obesity in Japanese men: a longitudinal analysis.

The beta 3-adrenergic receptor (beta 3AR) is implicated in the regulation of thermogenesis and lipolysis, and it is suggested that the Trp64 Arg mutation in this receptor may contribute to the development of obesity. To examine whether the Trp64 Arg mutation had any effect on body weight during adult life, the beta 3AR genotype was determined in 186 unselected Japanese men, most of whom had records of body weight measured yearly from 25-53 yr of age. Of them, 26 subjects were diagnosed as having noninsulin-dependent diabetes mellitus (NIDDM) and 41 as having impaired glucose tolerance. There were 6 subjects (3%) with homozygous mutation, 67 (36%) with heterozygous mutation, and 113 (61%) with normal allele. Among the 3 genotypes, there were no significant differences in body mass index (BMI) at any age between 25-53 yr and the prevalence of NIDDM at the age of 53 yr. When longitudinal changes in body weight were compared between subjects with and without mutation, the former were less prone to gain weight than the latter. The frequency of the mutant allele was 1) not different among obese (BMI, > 26.4), intermediate (BMI, 22-26.4), and nonobese (BMI, < 22.0) subjects (0.21, 0.22, and 0.26, respectively; P = 0.77); 2) lower in subjects with NIDDM than in those without it, but the difference was insignificant (0.12 vs. 0.23; P = 0.07); and 3) similar between 186 unselected men and another group of 100 patients with NIDDM that were randomly selected for comparison (0.21 vs. 0.23). These results suggest that the beta 3AR is not a major contributing factor to obesity or NIDDM in Japanese men.

Adult↗
PubMed1997

The coexistence of abdominal aortic aneurysm and advanced gastric cancer associated with recurrent angina after coronary artery bypass grafting.

A 76-year-old man with abdominal aortic aneurysm (AAA) and concomitant gastric cancer, who had undergone coronary artery bypass grafting (CABG), presented with recurrent exertional angina. Both lesions, the AAA and advanced gastric cancer, exhibited an absolute indication for urgent surgery. Coronary revascularization with percutaneous transluminal coronary angioplasty (PTCA) was carried out successfully before abdominal surgery. A one-stage abdominal operation was performed safely. The need for coronary revascularization complicates the treatment strategy for these patients with associated coronary artery disease. PTCA is the best option, especially if the patient presents with recurrent angina after prior CABG.

Aged↗
PubMed1997

Diabetic lipemia with maturity-onset diabetes of the young.

A 19-year-old woman with diabetic lipemia and maturity-onset diabetes of the young (MODY) is reported. Though her insulin secretory activity was preserved, she fell into mild diabetic ketoacidosis (DKA) and showed type V hyperlipidemia. Post-heparin plasma activity of lipoprotein lipase (LPL) was decreased even 10 days after initiating insulin injection but not deficient. The abnormalities in lipid metabolism were improved by long-term insulin treatment. Though the contribution of the genetic background to the lipid abnormalities is not clear, the characteristics of MODY in this patient including insulin secretory capacity under stress conditions such as DKA might play a role in the development of diabetic lipemia.

Adult↗
PubMed1997

Synthesis and structure-activity relationships of a novel oral carbapenem, CS-834.

We have studied an ester prodrug of a carbapenem to develop a potent orally active beta-lactam antibiotic. A variety of 1 beta-methylcarbapenem derivatives have been synthesized. We have found that some derivatives having an amide group in the C-2 side chain show potent and well balanced antibacterial activities as well as high stability against dehydropeptidase-I. Oral absorption of derivatives has been optimized by modifying the C-3 ester promoiety. Pivaloyloxymethyl (1R, 5S, 6S)-6-[(R)-1-hydroxyethyl]-l-methyl-2-[(R)-5-oxopyrrolidin-3-yl thio]- l-carbapen-2-em-3-carboxylate, CS-834, has been selected as the most promising compound for further evaluation.

Administration, Oral↗
PubMed1997

[Combination effect between panipenem and vancomycin on highly methicillin-resistant Staphylococcus aureus].

We investigated the in vitro and in vivo combination effects between panipenem (PAPM) and vancomycin (VCM) on highly methicillin-resistant strains of Staphylococcus aureus (MRSA) isolated from various clinical specimens. Examination of combination between panipenem and vancomycin using checkerboard titration showed a good effect with mean fractional inhibitory index of 0.32 +/- 0.12 on 40 MRSA strains, and the effects were judged as synergistic against 33 strains (83%) and additive against 7 strains (17%). In the combination of PAPM and VCM at 1/4 MIC each against exponentially growing MRSA, bactericidal activity was found when PAPM was added at 1 hour or 2 hours prior to VCM-addition, and PAPM with VCM was added simultaneously, although bactericidal activity was scarcely demonstrated when VCM was added at 1 hour or 2 hours prior to PAPM-addition. Bactericidal activity was enhanced against MRSA in the combination of PAPM and VCM at 1/4 MIC each for MRSA than the bactericidal activity of VCM at 1 MIC alone, and the combination showed a strong bactericidal activity against P. aeruginosa. VCM alone, however, had no bactericidal activity in the in vitro mixed cultures of the two bacteria. Furthermore, the combination of PAPM and VCM induced a marked damage to cell surface and bacteriolysis against MRSA and P. aeruginosa in the mixed cultures, although VCM alone induced only slight morphological alterations. Penicillin-binding proteins (PBPs) including MRSA-specific PBP 2' were decreased greatly in the amounts in MRSA-cells with the increase of VCM-treated concentration. The combination therapy of PAPM and VCM showed a greater efficacy than the therapeutic efficacy of each antibiotic alone against mixed infection in burned mice caused by MRSA and P. aeruginosa, and the activity was judged as synergistic based on the FED index smaller than 0.34.

Animals↗
PubMed1996

Vanadate triggers the transition from chromosome condensation to decondensation in a mitotic mutant (tsTM13) inactivation of p34cdc2/H1 kinase and dephosphorylation of mitosis-specific histone H3.

At the nonpermissive temperature (39 degrees C), chromosomes remain condensed in a temperature-sensitive cell mutant (tsTM13) arrested in the late stage of mitosis. Highly increased activity of histone H1 kinase, hyperphosphorylation of histone H1, and mitosis-specific histone H3 phosphorylation are maintained, even in telophase. In the present study, the defect of chromosome decondensation in tsTM13 cells was found to be partially normalized by a tyrosine phosphatase inhibitor, vanadate, with induction of chromosome decondensation and the formation of multinucleated cells. In the presence of vanadate, the H1 kinase activity dropped to near normal levels and the amount of the inactive from of p34cdc2 protein phosphorylated at a tyrosine residue was increased. H1 and H3 were also extensively de- phosphorylated, the latter being tightly associated with chromosome decondensation. Serine/threonine-protein phosphatase in late mitosis of the mutant works normally at 39 degrees C. The results indicate that (a) the genetic defect in the mutant may be involved in the control mechanism of the p34cdc2/H1 kinase activity in the late M phase rather than the phosphatase, (b) normalization of the defect of the mutant by vanadate results from inactivation of H1 kinase, and (c) late mitosis-specific events (p34cdc2/H1 kinase inactivation, mitosis-specific dephosphorylation of histone H1 and H3) are closely operating with chromosome decondensation.

CDC2 Protein Kinase↗
PubMed1996

Role of the prenyl group on the G protein gamma subunit in coupling trimeric G proteins to A1 adenosine receptors.

The coupling of receptors to heterotrimeric G proteins is determined by interactions between the receptor and the G protein alpha subunits and by the composition of the betagamma dimers. To determine the role of the gamma subunit prenyl modification in this interaction, the CaaX motifs in the gamma1 and gamma2 subunits were altered to direct modification with different prenyl groups, recombinant betagamma dimers expressed in the baculovirus/Sf9 insect cell system, and the dimers purified. The activity of the betagamma dimers was compared in two assays: formation of the high affinity agonist binding conformation of the A1 adenosine receptor and receptor-catalyzed exchange of GDP for GTP on the alpha subunit. The beta1gamma1 dimer (modified with farnesyl) was significantly less effective than beta1gamma2 (modified with geranylgeranyl) in either assay. The beta1gamma1-S74L dimer (modified with geranylgeranyl) was nearly as effective as beta1gamma2 in either assay. The beta1gamma2-L71S dimer (modified with farnesyl) was significantly less active than beta1gamma2. Using 125I-labeled betagamma subunits, it was determined that native and altered betagamma dimers reconstituted equally well into Sf9 membranes containing A1 adenosine receptors. These data suggest that the prenyl group on the gamma subunit is an important determinant of the interaction between receptors and G protein gamma subunits.

Animals↗
PubMed1996

Modulation of rhythmical slow activity, long-term potentiation and memory by muscarinic receptor agonists.

We investigated the cholinergic modulation of hippocampal rhythmical slow activity (or theta activity), long-term potentiation and a behavioral memory task. The intravenous administration of the muscarinic receptor agonists, AF102B ((+/-)-cis-2-methyl-spiro(1,3-oxathiolane-5,3') quinuclidine hydrochloride hemihidrate) and oxotremorine, induced rhythmical slow activity at doses of 1.0 mg/kg and 0.01 mg/kg, respectively. Long-term potentiation of population spike amplitude in the hippocampal CA1, which was induced by tetanic stimulation to the Schaffer collateral/commissural fiber, was increased by AF102B (1.0 mg/kg i.v.) and oxotremorine (0.01 mg/kg i.v.). Oral administration of AF102B and oxotremorine improved scopolamine-induced memory deficits in a passive avoidance task in mice at doses of 1.0 mg/kg and 0.2 mg/kg, respectively. The correspondence of the effective doses of muscarinic receptor agonists in these three experiments suggested the cholinergic correlation of rhythmical slow activity, long-term potentiation and memory.

Administration, Oral↗
PubMed1996

Rapid growth of hepatocellular carcinoma after or during interferon treatment of chronic hepatitis C: report of three cases.

We report herein the cases of three patients in whom marked rapid growth of hepatocellular carcinoma (HCC) became evident after or during interferon (IFN) treatment for chronic hepatitis C. The HCC tumors were 10, 4.7, and 3.1 cm in size, and were found 7 months, 10 weeks, and 10 weeks after the initiation of IFN, respectively, in cases 1, 2, and 3. The clinical courses of these three patients suggest that the progression of HCC was more rapid during the IFN treatment period. Thus, we propose that abdominal ultrasonic (US) examination should be performed monthly in patients with chronic hepatitis who undergo IFN treatment.

Adult↗
PubMed1996

Alpha N-catenin expression in the normal and regenerating chick sciatic nerve.

The Ca(2+)-dependent intercellular adhesion molecule cadherin is known to be linked to the cytoskeleton by the protein catenin, an association of which appears to be important for the cell-adhesion function of cadherin. Catenin consists of three subtypes-alpha, beta, and gamma. In our previous study, N-cadherin was shown to be localized on the plasmalemma of normal and regenerating chick peripheral nerve. Thus, as alpha N-catenin is a subtype of alpha-catenin (which is specifically associated with N-cadherin), we investigated the immunolocalization of alpha N-catenin in normal and regenerating chick sciatic nerve. In normal nerve, unmyelinated axons exhibited either intense or weak alpha N-catenin immunoreactivity throughout the axoplasm, whereas myelinated axons were completely immunonegative. Regenerating axons, including those derived from parent myelinated axons, showed alpha N-catenin immunoreactivity of variable intensities in growth cones and axon shafts. Schwann cells were invariably devoid of immunoreactivity. Thus alpha N-catenin is not necessarily bound to the surface plasmalemma, but is distributed throughout the cytoplasm, suggesting that most alpha N-catenin molecules are dissociated from N-cadherin.

Animals↗