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Biomedical subjects

M Hayashi

Publications and source records attributed to M Hayashi.

At least 181 records · Page 10Linked to original sources
PubMed2001

Rare case of biphasic tumor of the breast with prominent CD34-positive spindle cells.

We report an unusual case of biphasic tumor of the breast with prominent CD34-positive spindle cells. A 53-year-old woman presented with a mass in her right breast. Following an incisional biopsy, a partial mastectomy was done. Histologically, the tumor was a biphasic variant of a malignant spindle cell tumor of the breast. The lack of a leaf-like structure, together with the apparent myoid features of the spindle-shaped tumor cells, made it difficult to distinguish from malignant phyllodes tumor and from myoepithelial carcinoma. Immunohistochemistry revealed the spindle-shaped tumor cells to be myofibroblastic, but not myoepithelial in nature, ultimately categorizing this tumor as a malignant phyllodes tumor with prominent myofibroblastic differentiation.

Antigens, CD34↗
PubMed2001

A randomized comparison of the straight linear approach with electrogram mapping focal approach in selective slow pathway ablation.

The aim of this study was to evaluate the efficacy and safety of the anatomic linear approach in selective AVN slow pathway ablation, in comparison to the widely used electrogram mapping focal approach. It remains undetermined whether or not anatomic linear ablation has a greater potential for eliminating slow pathway conduction than does focal ablation. Fifty consecutive patients (21 men, 29 women, age 56 +/- 14 years) with common type AVNRT were randomly assigned to the linear approach (25 patients) or local electrogram mapping approach (25 patients). A linear lesion was created between the tricuspid annulus, at the midlevel of the coronary sinus (CS) ostium, and the anterior aspect of the CS infundibulum. In 22 (88%) patients in the linear group, the AVNRT was successfully eliminated by 1.5 +/- 0.8 linear RF applications without any complications. All 25 patients in the focal group satisfied the endpoint criteria after 3.8 +/- 2.4 focal RF deliveries. The success rate did not significantly differ between the two groups. Out of the 22 patients with a successful outcome in the linear group, 17 (77%) attained complete abolition of the slow pathway conduction, whereas this was observed in only eight (32%) patients in the focal group (P < 0.005). The session time was significantly shorter in the linear group. Recurrence of the tachycardia was not documented in any patient during a mean follow-up of 18 +/- 8 months except one with residual slow pathway conduction in the focal ablation group. In conclusion, the anatomic linear approach can be performed safely and possesses a greater potential for slow pathway interruption compared to the electrogram mapping focal approach.

Adult↗
PubMed2001

Eccrine syringofibroadenoma: case report and review of the literature.

Eccrine syringofibroadenoma (ESFA) is a rare disorder that shows differentiation toward eccrine sweat apparatus. There is a controversy concerning the pathogenesis and differentiation of this tumour. We report a case of ESFA in a 63-year-old Japanese man. We review the literature presenting a classification, including a newly reported subtype. Clinically and pathogenically, ESFA is probably a group of heterogeneous disorders.

Adenoma, Sweat Gland↗
PubMed2001

Growth/differentiation factor 7 is preferentially expressed in the primary motor area of the monkey neocortex.

We applied a differential display PCR technique to isolate molecules that are area-specific in expression in the primate neocortex, and found that growth/differentiation factor 7 (GDF7), a member of the bone morphogenetic protein (BMP)/transforming growth factor (TGF) beta super-family, is preferentially expressed in the primary motor area of African green monkeys (Cercopithecus aethiops). We proved that GDF7 is 10 times more abundant in the motor cortex than in the visual cortex by northern blotting and quantitative RT-PCR. When we examined the neocortex of closely related rhesus monkeys (Macaca mulatta), GDF7 was also most abundant in the motor cortex, although the regional difference was reduced to 3-fold. This differential expression pattern was observed in both newborn and infant rhesus monkeys. We found that several type I/II receptors of BMP, candidates of the receptors for GDF7, are uniformly expressed in the mature neocortex. The unique expression pattern of GDF7 suggests that it may play an active role in the motor area of the primate neocortex.

Aging↗
PubMed2001

Phosphorylation of a new member of the bicarbonate cotransporter superfamily.

Acid-base balance is regulated by cortical collecting duct cells in kidney, where the transporter functions of beta-intercalated cells are controlled by such factors as isoproterenol, cyclic adenosine monophosphate (cAMP), and the protein kinase A (PKA) pathway. The apical anion exchanger (AE) in beta-intercalated cells is thought to be involved in the secretion of bicarbonate into urine. In isolated cells, the Cl- channel was shown to be activated by isoproterenol via the PKA pathway. The importance of the PKA pathway and phosphorylation in the regulation of its transporter activity is not yet known.

Animals↗
PubMed2001

Relationship between plasma levels of cardiac natriuretic peptides and soluble Fas: plasma soluble Fas as a prognostic predictor in patients with congestive heart failure.

BACKGROUND: Cardiac natriuretic peptides may induce apoptosis in myocytes; however, the relationship between plasma levels of cardiac natriuretic peptides and those of soluble Fas (sFas) and tumor necrosis factor (TNF)-alpha remains unknown in patients with congestive heart failure (CHF). METHODS AND RESULTS: We measured plasma levels of sFas and TNF-alpha and those of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), norepinephrine, and endothelin 1 in 96 patients with CHF (ejection fraction < 45%). The patients were monitored for 3 years. Plasma levels of sFas and TNF-alpha increased with the severity of CHF. There was no significant correlation between sFas plasma levels and those of ANP and BNP. Cox proportional hazard analysis showed that high levels of sFas (P = .009) and BNP (P < .0001) and a low ejection fraction (P = .019) were independent significant prognostic predictors. CONCLUSIONS: There is no significant correlation between cardiac natriuretic peptide and sFas levels in plasma. Plasma sFas is a useful prognostic marker independent of neurohumoral factors, suggesting that immune activation and/or apoptosis play a significant role in the pathogenesis of CHF.

Age Factors↗
PubMed2001

Involvement of inducible nitric oxide synthase in cataract formation in Shumiya cataract rat (SCR).

PURPOSE: Our previous results showed that the oral administration of aminoguanidine (AG), an inhibitor of inducible nitric oxide synthase (iNOS), strongly suppresses lens opacification in Shumiya cataract rat (SCR). Therefore, we examine whether iNOS is upregulated and involved in cataract formation in SCR. METHODS: The expressions of iNOS mRNA and iNOS protein in SCR lenses were examined by RT-PCR and Western blotting, respectively. Calpain-mediated alphaB-crystallin proteolysis was analyzed by Western blotting using antibody specific to the calpain-generated fragment of alphaB-crystallin. Lens opacification was analyzed using computerized image analysis software connected to the Anterior Eye Segment Analysis System (EAS-1000, Nidek). Calcium contents in lenses were measured by atomic absorption spectrophotometry. RESULTS: High levels of iNOS mRNA and iNOS protein are expressed in cataractous lenses compared with normal lenses. The increases in their expression are markedly suppressed by the oral administration of AG, which acts to prevent lens opacification. The induction of iNOS protein is observed before the elevation in calcium content and the acceleration of calpain-mediated proteolysis, both of which are closely related to the development of lens opacification. CONCLUSIONS: These findings strongly suggest that iNOS is involved in cataract formation in SCR. The induction of iNOS occurs prior to the elevation of calcium content and its induction is inhibited by AG-treatment. Considering our previous result that the elevation of calcium content is also prevented by AG-treatment, it is conceivable that upregulation of iNOS causes calcium influx into lens cells and the subsequent activation of calpain.

Animals↗
PubMed2001

Lack of interaction between bropirimine and 5-fluorouracil on human dihydropyrimidine dehydrogenase.

1. Bropirimine (2-amino-5-bromo-6-phenyl-4-pyrimidinone) is a member of a class of antineoplastic agents that are administered concomitantly or sequentially with anticancer 5-fluorouracil (5-FU) prodrugs in clinical patients. Interactions between bropirimine and 5-fluorouracil (5-FU) were investigated on dihydropyrimidine dehydrogenase (DPD) activity, the rate-limiting enzyme of 5-FU metabolism, in human liver cytosol. Apparent DPD activity was determined by measuring the recovery of [14C]5-FU by HPLC. 2. The apparent activity of 5-FU metabolism (2.1-100 microM) showed a linear relationship in the Eadie-Hofstee plot in the pooled cytosol, suggesting that a single enzyme is responsible for apparent 5-FU metabolism. Km and Vmax were estimated to be 23 microM and 0.32 nmol min(-1) mg(-1) protein, respectively. Apparent DPD activity for 5-FU (25 microM) in the cytosol from 12 individual donors ranged from 0.017 to 0.39 (0.16 +/- 0.12) nmol min(-1) mg(-1) protein, indicating a large intersubject variance. 3. The suicidal inactivators of the DPD enzyme, (E)-5-(2-bromovinyl)uracil and 5-bromouracil (6.3-50 microM), illustrated concentration-dependent inhibition on DPD activity. Isocytosine (6.3-100 microM), used as a negative control, did not affect DPD activity. Bropirimine (6.3-100 microM) also did not show any inhibition of DPD activity. Therefore, bropirimine is unlikely to cause increases in 5-FU levels in clinical patients after co-administration of bropirimine with 5-FU prodrugs.

Adolescent↗
PubMed2001

Significance of platelet aggregability immediately after blood sampling and effect of cigarette smoking.

A novel type platelet aggregometer, a WBA Analyzer, has enabled us to obtain the platelet aggregability data immediately after blood sampling, which is considered to closely reflect in vivo platelet function. Using this analyzer, we measured the platelet aggregatory threshold index (PATI) 5 min after blood sampling and compared it with that 60 min after blood sampling in 20 healthy male volunteers (10 smokers and 10 non-smokers). In the non-smokers, PATI was 10.3+/-2.3 microM 5 min after blood sampling, and it decreased to 4.7+/-1.5 (P<0.001) 60 min after blood sampling. In the smokers, the PATI was 7.7+/-2.9 microM 5 min after blood sampling, and it decreased to 3.8+/-1.5 (P<0.001) at 60 min after blood sampling. In the smokers, the PATI 5 min after blood sampling increased after a 4-week cessation of smoking (10.4+/-2.9, P<0.01), although the PATI 60 min after blood sampling did not change (4.2+/-1.6 microM). The measurement of platelet aggregability immediately after blood sampling using a WBA Analyser may be useful to evaluate not only platelet function in various thrombotic disorders, but also the effects of various anti-platelet drugs. Cessation of smoking should also be encouraged in the light of the adverse effects on platelet function.

Adult↗
PubMed2001

Oxidative stress and disturbed glutamate transport in hereditary nucleotide repair disorders.

Xeroderma pigmentosum group A (XPA) and Cockayne syndrome (CS) are hereditary DNA repair disorders complicated by progressive neurodegeneration. Here we immunohistochemically examine the in situ expression of materials that are produced by oxidative stress and glutamate transporters (which can contribute to prevention of glutamate neurotoxicity) in the brains of 5 autopsied patients each of XPA, CS, and control groups. All oxidative products, including nitrotyrosine, advanced glycation end product, and 4-hydroxy-2-nonenal-modified protein (HNE) were deposited in large amounts in the globus pallidus of CS patients compared to XPA patients. They were frequently recognized in the pseudocalcified foci and free minerals in the neuropil, and more rarely in foamy spheroids. In addition, the deposition of HNE was observed also in hippocampal and cerebellar dentate neurons of both CS and XPA patients. The expression of glial glutamate transporters, EAAT1 and GLT-1, was affected in the globus pallidus in 5 CS patients and 3 XPA patients. They were also altered in the cerebellar cortex in most of the CS patients. These data suggest that oxidative stress and disturbed glutamate transport may be involved in pallidal and/or cerebellar degeneration in hereditary nucleotide repair disorders.

ATP-Binding Cassette Transporters↗
PubMed2001

Pumpkin peroxisomal ascorbate peroxidase is localized on peroxisomal membranes and unknown membranous structures.

To investigate the roles of peroxisomal membrane proteins in the reversible conversion of glyoxysomes to leaf peroxisomes, we characterized several membrane proteins of glyoxysomes. One of them was identified as an ascorbate peroxidase (pAPX) that is localized on glyoxysomal membranes. Its cDNA was isolated by immunoscreening. The deduced amino acid sequence encoded by the cDNA insert does not have a peroxisomal targeting signal (PTS), suggesting that pAPX is imported by one or more PTS-independent pathways. Subcellular fractionation of 3- and 5-d-old cotyledons of pumpkin revealed that pAPX was localized not only in the glyoxysomal fraction, but also in the ER fraction. A magnesium shift experiment showed that the density of pAPX in the ER fraction did not increase in the presence of Mg(2+), indicating that pAPX is not localized in the rough ER. Immunocytochemical analysis using a transgenic Arabidopsis which expressed pumpkin pAPX showed that pAPX was localized on peroxisomal membranes, and also on a unknown membranous structure in green cotyledons. The overall results suggested that pAPX is transported to glyoxysomal membranes via this unknown membranous structure.

Amino Acid Sequence↗
PubMed2001

Developmental analysis of a putative ATP/ADP carrier protein localized on glyoxysomal membranes during the peroxisome transition in pumpkin cotyledons.

In order to clarify the peroxisomal membrane proteins (PMPs), we characterized one of the major PMPs, PMP38. The deduced amino acid sequence for its cDNA in Arabidopsis thaliana contained polypeptides with 331 amino acids and had high similarity with those of Homo sapiens PMP34 and Candida boidinii PMP47 known as homologues of mitochondrial ATP/ADP carrier protein. We expected PMP38 to be localized on peroxisomal membranes, because it had the membrane peroxisomal targeting signal. Cell fractionation and immunocytochemical analysis using pumpkin cotyledons revealed that PMP38 is localized on peroxisomal membranes as an integral membrane protein. The amount of PMP38 in pumpkin cotyledons increased and reached the maximum protein level after 6 d in the dark but decreased thereafter. Illumination of the seedlings caused a significant decrease in the amount of the protein. These results clearly showed that the membrane protein PMP38 in glyoxysomes changes dramatically during the transformation of glyoxysomes to leaf peroxisomes, as do the other glyoxysomal enzymes, especially enzymes of the fatty acid beta-oxidation cycle, that are localized in the matrix of glyoxysomes.

Amino Acid Sequence↗
PubMed2001

Evidence that human epididymal protein ARP plays a role in gamete fusion through complementary sites on the surface of the human egg.

Human epididymal sperm protein ARP, a member of the cysteine-rich secretory proteins (CRISP) family, exhibits significant homology with rat epididymal protein DE, a candidate molecule for mediating sperm-egg fusion in rodents. The aim of this study was to investigate the involvement of ARP in human gamete fusion. Sequential extraction of proteins from ejaculated human sperm revealed the existence of a population of ARP that is tightly associated with the sperm surface and thus, potentially capable of participating in gamete interaction. Exposure of capacitated human sperm to a polyclonal antibody against recombinant ARP (anti-ARP) produced a significant and concentration-dependent inhibition in the ability of human sperm to penetrate zona-free hamster eggs. This inhibition was not due to a deleterious effect on the gametes because anti-ARP affected neither sperm viability or motility, nor egg penetrability. The antibody did not inhibit the occurrence of spontaneous or Ca(2+) ionophore-induced acrosome reaction, nor did it inhibit the ability of sperm to bind to the oolema, supporting a specific inhibition of the antibody at the sperm-egg fusion level. As a relevant evidence for a role of ARP in gamete fusion, the existence of complementary sites for this protein on the surface of human eggs was investigated. Experiments in which zona-free human oocytes discarded from in vitro fertilization programs were exposed to ARP, fixed, and subjected to indirect immunofluorescence revealed the presence of specific ARP-binding sites on the entire surface of the human egg, in agreement with the fusogenic properties of the human oolema. Together, these results strongly support the participation of ARP in the sperm-egg fusion process, suggesting that this protein would be the functional homologue of DE in humans.

Animals↗
PubMed2001

Increased excretion of N-acetyl-beta-D-glucosaminidase and beta2-microglobulin in gestational week 30.

BACKGROUND: Little is known about when the urinary excretion of a combination of N-acetyl-beta-D-glucosaminidase (NAG) and beta2-microglobulin (beta2MG) concentration [relative to creatinine (Cr)] reaches maximal values during uncomplicated normotensive pregnancy. This study was thus designed to analyze when urinary excretion of biochemical parameters was increased during normotensive pregnancy. METHODS: NAG, beta2MG, total protein, albumin, and Cr were simultaneously measured in random (untimed) midstream urine samples from 22 healthy nonpregnant women and from 82 normotensive pregnant women (22 in gestational week 20, 25 in week 30, and 35 in week 37). RESULTS: NAG/Cr and beta2MG/Cr ratios were significantly higher (P < 0.01-0.05) in the normotensive pregnant women in gestational week 30 than in the nonpregnant control subjects and normotensive pregnant women in gestational week 20. The NAG/Cr and beta2MG/Cr ratios showed maximal values in gestational week 30. The total protein/Cr ratio was significantly higher in gestational weeks 20, 30, and 37 than in the control subjects. The albumin/Cr ratio was significantly higher in women in gestational week 30 and 37 than in women in gestational week 20 and in the control subjects. CONCLUSIONS: The excretion of both NAG and beta2MG relative to Cr was increased and showed the maximal values in gestational week 30 during normotensive pregnancy. The increase in a tubular enzyme (NAG) might be caused by renal tubular damage, and that in a low molecular weight protein (beta2MG) might result from decreased renal tubular reabsorption. These findings suggest that renal tubular damage and reabsorption dysfunction were increased in gestational week 30.

Acetylglucosaminidase↗
PubMed2001

Downward extension of the lacrimal gland under the bulbar conjunctiva after trabeculectomy.

PURPOSE: To describe two cases in which the lacrimal gland was considered to extend downward under the bulbar conjuctiva following trabeculectomy. PATIENTS AND METHODS: We report two patients who complained of epiphora after trabeculectomy. A biopsy was performed on the tissue under the bulbar conjunctiva on the periphery of the bleb of case 1. The anatomical relationship between the holes and the avascular filtering bleb in case 2 was investigated using ultrasound biomicroscopy. RESULTS: In case 1, a biopsy showed the lacrimal gland tissue filtrated with mononuclear cells. In case 2, ultrasound biomicroscopy revealed no connection between the multiple leaking holes and localized filtering bleb. CONCLUSION: Following trabeculectomy at the superior temporal quadrant, we should consider downward extension of the lacrimal gland as a possible source of a patient's complaint of epiphora.

Adult↗
PubMed2001

Distribution and diversity of symbiotic thermophiles, Symbiobacterium thermophilum and related bacteria, in natural environments.

Symbiobacterium thermophilum is a tryptophanase-positive thermophile which shows normal growth only in coculture with its supporting bacteria. Analysis of the 16S rRNA gene (rDNA) indicated that the bacterium belongs to a novel phylogenetic branch at the outermost position of the gram-positive bacterial group without clustering to any other known genus. Here we describe the distribution and diversity of S. thermophilum and related bacteria in the environment. Thermostable tryptophanase activity and amplification of the specific 16S rDNA fragment were effectively employed to detect the presence of Symbiobacterium. Enrichment with kanamycin raised detection sensitivity. Mixed cultures of thermophiles containing Symbiobacterium species were frequently obtained from compost, soil, animal feces, and contents in the intestinal tracts, as well as feeds. Phylogenetic analysis and denaturing gradient gel electrophoresis of the specific 16S rDNA amplicons revealed a diversity of this group of bacteria in the environment.

Animals↗
PubMed2001

Role of trehalose in growth at high temperature of Salmonella enterica serovar Typhimurium.

Moderate osmolality can stimulate bacterial growth at temperatures near the upper limit for growth. We investigated the mechanism by which high osmolality enhances the thermotolerance of Salmonella enterica serovar Typhimurium, by isolating bacteriophage MudI1734-induced insertion mutations that blocked the growth-stimulatory effect of 0.2 M NaCl at 45 degrees C. One of these mutations proved to be in the seqA gene (a regulator of initiation of DNA synthesis). Because this gene is cotranscribed with pgm (which encodes phosphoglucomutase), it is likely to be polar on the expression of the pgm gene. Pgm catalyzes the conversion of glucose-6-phosphate to glucose-1-phosphate during growth on glucose, and therefore loss of Pgm results in a deficiency in a variety of cellular constituents derived from glucose-1-phosphate, including trehalose. To test the possibility that the growth defect of the seqA::MudI1734 mutant at high temperature in medium of high osmolality is due to the block in trehalose synthesis, we determined the effect of an otsA mutation, which inactivates the first step of the trehalose biosynthetic pathway. The otsA mutation caused a growth defect at 45 degrees C in minimal medium containing 0.2 M NaCl that was similar to that caused by the pgm mutation, but otsA did not affect growth rate in this medium at 37 degrees C. These results suggest that the growth defect of the seqA-pgm mutant at high temperature could be a consequence of the block in trehalose synthesis. We found that, in addition to the well-known osmotic control, there is a temperature-dependent control of trehalose synthesis such that, in medium containing 0.2 M NaCl, cells grown at 45 degrees C had a fivefold higher trehalose pool size than cells grown at 30 degrees C. Our observations that trehalose accumulation is thermoregulated and that mutations that block trehalose synthesis cause a growth defect at high temperature in media of high osmolality suggested that this disaccharide is crucial for growth at high temperature either for turgor maintenance or for protein stabilization.

Bacterial Outer Membrane Proteins↗