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Biomedical subjects

K Nishimura

Publications and source records attributed to K Nishimura.

At least 415 records · Page 23Linked to original sources
PubMed1996

Phylogeny of Epidermophyton floccosum and other dermatophytes.

Eleven strains of Epidermophyton floccosum were compared with 5 Microsporum and 5 Trichophyton species with respect to the restriction fragment length polymorphism (RFLP) of the mitochondrial DNA to reveal their phylogenetic relationships. The phylogeny of 11 species showed that the three dermatophyte genera could not be separated from each other and could be considered to be congeneric. This result is not inconsistent with the results from ribosomal RNA sequences.

DNA, Fungal↗
PubMed1996

Management of subarachnoid fluid collection in infants based on a long-term follow-up study.

We report the natural history and management of subarachnoid fluid collections in infants and their management based on a longterm follow-up study in 20 cases. These subarachnoid fluid collections were resolved spontaneously in 17 of 20 patients and only 3 by surgical intervention at the age of 2. In our 20 patients the natural history of subarachnoid fluid collection in infants was benign unless the patients sustained head trauma. Surgical treatment was performed in the cases where a subarachnoid fluid collection developed into a subdural haematoma. Head trauma may precipitate subdural haematoma in patients with subarachnoid fluid collection. All patients except one who underwent the placement of subdural-peritoneal shunt, attained normal psychomotor development in time. During the follow-up period of 3 to 10 years after resolution of the fluid collection, no patient has had a recurrence once it resolved.

Cerebrospinal Fluid Shunts↗
PubMed1996

99mTc-MIBI accumulation in the parathyroid autograft in a patient with recurrent hyperparathyroidism.

A case with recurrent hyperparathyroidism secondary to chronic renal insufficiency is reported. The patient had undergone total parathyroidectomy and autotransplantation of parathyroid tissue five years ago. Bone scintigraphy clearly demonstrated skeletal involvement of secondary hyperparathyroidism and 99mTc-methoxyisobutylisonitrile scintigraphy clearly demonstrated a hyperfunctioning parathyroid autograft.

Bone and Bones↗
PubMed1996

Effect of the insect growth regulators, N-tert-butyl-N, N'-dibenzoylhydrazines, on neural activity of the American cockroach.

N-tert-Butyl-N,N'-dibenzoylhydrazines, agonists of 20-hydroxyecdysone, decelerated the rising and falling phases of an action potential, which had been electrically induced in the cockroach giant axon, at moderately high concentrations. 4-Aminopyridine, a blocker of potassium channels of nerve, selectively decelerated the falling phase of the action potential. This class of compounds caused convulsions in American cockroaches when injected. The convulsive activity seemed to be positively related to the activity to decelerate the falling phase of the action potential.

4-Aminopyridine↗
PubMed1996

Analysis of right ventricular function during bypass of the left side of the heart by afterload alterations in both normal and failing hearts.

This study investigated the mechanism of right ventricular failure during bypass of the left side of the heart by precisely assessing right ventricular function with use of a conductance catheter. Bypass of the left side of the heart was established with a centrifugal pump in 10 mongrel dogs weighing 11 to 19 kg. Right ventricular function during left heart bypass was evaluated by two parameters that were both derived from measurement of relative change in right ventricular volume by the conductance catheter technique. One parameter was the right ventricular end-systolic pressure-volume relationship as a load-independent index, and the other was the peak right ventricular pressure-right ventricular stroke volume relationship as a "force-velocity relationship." These parameters were measured in both normal and failing hearts while afterload was increased by bilateral intrapulmonary balloon inflation. Moreover, changes in these relationships were observed by varying assist ratios of left heart bypass from 0% to 100%. Failing heart models were induced by normothermic aortic clamping for 20 minutes. The right ventricular end-systolic pressure-volume relationship in normal hearts did not change, irrespective of the assist ratio of left heart bypass, whereas that in failing hearts decreased from 4.25 +/- 1.41 mm Hg/ml without bypass of the left side of the heart to 3.53 +/- 1.30 mm Hg/ml after 100% assist of left heart bypass (p < 0.05). In the peak right ventricular pressure-right ventricular stroke volume relationship, right ventricular stroke volume was almost constant in normal hearts when afterload was increased regardless of the assist ratio of left heart bypass. Moreover, right ventricular stroke volume was maintained at a higher level during bypass of the left side of the heart compared with that without left heart bypass. However, that slope of the relationship in failing hearts was inversely linear and became significantly steeper after 100% assist of bypass of the left side of the heart compared with that without left heart bypass (-0.131 +/- 0.042 versus -0.051 +/- 0.038, p < 0.005). Therefore ++these two slopes of the relationship intersected at a point that was considered the critical point of afterload during bypass of the left side of the heart. In other words, right ventricular stroke volume was decreased by 100% left heart bypass above the critical point of afterload. In conclusion, this study demonstrates not only that bypass of the left side of the heart results in an increase in right ventricular stroke volume in both normal and failing hearts at the physiologic range of afterload, but also that right ventricular function against higher afterload is impaired by 100% assist of bypass of the left side of the heart in failing hearts.

Animals↗
PubMed1996

Influence of baseline airway calibre and pulmonary emphysema on bronchial responsiveness in patients with chronic obstructive pulmonary disease.

STUDY OBJECTIVE: Bronchial hyper-responsiveness (BHR) is widely observed in patients with chronic obstructive pulmonary disease (COPD). However, its clinical significance in COPD has not yet been established. To determine the factors that influence BHR in COPD, multiple linear regression analysis was used to analyse the relationship between BHR to methacholine and baseline forced expiratory volume in 1 s (FEV1), vital capacity (VC), residual volume (RV)/total lung capacity (TLC), static compliance (Cst), transfer coefficient of the lung (Kco), and the percentage of low attenuation area (%LAA) determined by computed tomographic (CT) scan. METHODS: Bronchial responsiveness to methacholine was determined in 63 patients with COPD by the dosimeter method and expressed as PD20FEV1. Residual volume and TLC were determined by body plethysmography. The percentage of low attenuation area was defined as the percentage of area less than -960 Hounsfield unit on a CT scan of the thorax. RESULTS: Forced expiratory volume in 1s (%predicted) and %LAA correlated with BHR (P = 0.023 and 0.020, respectively), while VC (%pred), RV/TLC, Cst and Kco did not. The coefficient of determination was 0.43. The regression analysis showed that a 10% increase in FEV1 (%pred) and a 10% decrease in %LAA would increase log(PD20FEV1) by 0.145 and 0.117, respectively. CONCLUSIONS: A considerable proportion of the BHR in COPD is related to functional abnormalities and morphologic changes of emphysema, such as decreased baseline airway calibre and destruction of the lung parenchyma.

Aged↗
PubMed1996

Dysfunction of cholinergic and dopaminergic neuronal systems in beta-amyloid protein--infused rats.

Accumulations of beta-amyloid protein are characteristic and diagnostic features of the brain of Alzheimer's disease patients; however, the physiological role of this protein in CNS is unknown. We have previously reported that continuous infusion of beta-amyloid protein into rat cerebral ventricle impairs learning ability and decreases choline acetyltransferase activity, a marker enzyme of cholinergic neuron. In this study, the effects of beta-amyloid protein infusion on the release of neurotransmitters in cholinergic and dopaminergic neuronal systems were investigated by using an in vivo brain microdialysis method. Nicotine-stimulated release of acetylcholine and dopamine in these animals was significantly lower than that in vehicle-infused rats. Further, dopamine release induced by high-K stimulation was decreased in beta-amyloid protein-infused rats compared with vehicle-infused rats. These results suggest that the release of the two transmitters, acetylcholine and dopamine, was decreased by beta-amyloid protein and that learning deficits observed in the beta-amyloid protein-infused rats are partly due to the impairment of neurotransmitter release. Furthermore, continuous infusion of beta-amyloid protein may be a useful method to produce the animal model of Alzheimer's disease.

Acetylcholine↗
PubMed1996

Effects of endothelin-1 on optic nerve head blood flow in cats.

We determined the effects of endothelin-1 on optic nerve head (ONH) blood flow in anesthetized cats. Endothelin-1 (50-2500 pmol) injected into the vitreous produced a dose-related and sustained decrease (22 +/- 6% by 500 pmol and 36 +/- 11% by 2500 pmol) in the ONH blood flow. Blood pressure (BP) and heart rate (HR) remained, however, unchanged. In contrast, intravenous (i.v.) injected endothelin-1 (0.004-0.4 nmol kg-1) produced a dose-related and short-lasting increase in the ONH blood flow; its maximum increase by 0.4 nmol kg-1 was 135 +/- 34%. Endothelin-1, at 0.4 nmol kg-1, i.v., produced a transient decrease followed by a more sustained increase in BP, but had no remarkable effect on HR. The increase in ONH blood flow by i.v. injection of endothelin-1 was abolished by N(G)-nitro-L-arginine methyl ester (L-NAME, 5 mg kg-1 min-1, i.v.). The suppression of blood flow by L-NAME was reversed by the addition of L-arginine (50 mg kg-1 min-1). Pressor responses to endothelin-1 (0.4 nmol kg-1, i.v.) were augmented in the presence of L-NAME, but reversed in combination with L-arginine. These findings suggest that i.v. injection of endothelin-1 causes NO release from endothelial cells which increases ONH blood flow, whereas intravitreal injection of endothelin-1 decreases ONH blood flow by its vasoconstrictive effect. Different populations of ET receptors on vascular smooth muscles or endothelial cells would reflect the opposing effects of endothelin-1.

Animals↗
PubMed1996

Bronchial mucoid impaction due to the monokaryotic mycelium of Schizophyllum commune.

We report, to our knowledge, the first case of mucoid impaction of the bronchi due to a hypersensitivity reaction to the monokaryotic mycelium of Schizophyllum commune. The patient was hospitalized because of mild asthma attacks, persistent cough, peripheral eosinophilia, and "gloved finger" shadows on a chest roentgenogram. Bronchoscopic examination disclosed mucoid impactions that consisted of accumulations of eosinophils, Charcot-Leyden crystals, and nondichotomously branched hyphae in B3, B9, and B10 of the left lung. Cultures of the mucous plugs and sputum samples yielded white, felt-like mycelial colonies that were later identified as the monokaryotic mycelium of S. commune by use of mating tests with established monokaryotic and dikaryotic strains of S. commune. The results of tests for serum antibody to S. commune cytosol antigen were positive. Repeated bronchoscopies for performing bronchial toilet were effective in removing the mucous plugs and relieving the patient's symptoms. We suggest that the monokaryotic mycelium of S. commune should be considered as one of the fungi that can cause hypersensitivity-related lung diseases.

Aged↗
PubMed1996

Expression of the puf operon in an aerobic photosynthetic bacterium, Roseobacter denitrificans.

The effects of oxygen and light on the expression of the puf operon were investigated in Roseobacter denitrificans in a comparison with those in Rhodobacter sphaeroides. In darkness, the levels of the total puf mRNA in Ros. denitrificans were about 1.3 times those in Rb. sphaeroides at low concentrations of oxygen, reflecting the accumulation of bacteriochlorophyll and carotenoids. The oxygen tension, up to 94% saturation of dissolved oxygen, did not affect the levels of the total puf transcripts in Ros. denitrificans, whereas those in Rb. sphaeroides were reduced to 55% of the maximum level even at 50% saturation. Four puf-specific transcripts were detected: a 0.5-kb transcript was the most abundant; 1.2-kb and 1.9-kb transcripts accumulated at low levels; and a 3.5-kb transcript accumulated at very low levels under all conditions tested. The levels of the individual transcripts were barely affected by molecular oxygen. An S-1 nuclease protection assay revealed that the 0.5-kb transcript encoded the LHI-alpha and LHI-beta subunits (pufBA), the 1.2-kb transcript encoded puf-BA and part of pufL, and the 1.9-kb transcript encoded pufBAL and part of pufM. It was not clear whether the 3.5-kb transcript encoded the entire pufBALM and the gene for the polypeptide moiety of cytochrome c. The difference in levels between the 0.5-kb transcript and the other transcripts (1.2 kb, 1.9 kb, and 3.5 kb) was presumed to be due to the presence of several stem-loop structures at the 3' terminus of the 0.5-kb transcript which acted as terminators of transcription and, possibly, as protection against nucleolytic digestion. Light inhibited the expression of the puf operon in Ros. denitrificans more effectively than that in Rb. sphaeroides. The insensitivity to oxygen, as well as the sensitivity to light, of the expression of the puf operon in Ros. denitrificans, which was different from that in Rb. sphaeroides, seemed to represent a mode of adaptation that allowed the former cells to avoid photodynamic damage by light under highly aerobic conditions.

Bacteria↗
PubMed1996

A transcription factor with a leucine-zipper motif involved in light-dependent inhibition of expression of the puf operon in the photosynthetic bacterium Rhodobacter sphaeroides.

In the purple nonsulfur photosynthetic bacterium Rhodobacter sphaeroides the synthesis of components of the photosystem is regulated in response to oxygen tension and light intensity. We have purified and cloned a trans-acting protein (SPB) that binds to the promoter region of the puf operon, which encodes the apoproteins of light-harvesting complex I and the reaction center. The SPB was composed of a single polypeptide with an apparent molecular mass of 15.0 kDa. The nucleotide sequence of the spb gene was determined. The gene encoded 104 amino acid residues, which correspond to a molecular mass of 11.5 kDa. SPB exhibited 53% homology to HvrA in Rhodobacter capsulatus. The deduced amino acid sequence indicated that SPB contained a region with homology to the leucine-zipper motif of c-JUN, a transcription factor in eukaryotes, and SPB also had a DNA-binding domain on the amino-terminal side of the leucine-zipper motif. The leucine-zipper motif of SPB might contribute to the formation of a dimer. Northern analysis indicated that spb was constitutively and monocistronically transcribed in R. sphaeroides, irrespective of growth conditions. Structural and functional differences between SPB and HvrA are discussed.

Amino Acid Sequence↗
PubMed1996

Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max.

This study consists of two training experiments using a mechanically braked cycle ergometer. First, the effect of 6 wk of moderate-intensity endurance training (intensity: 70% of maximal oxygen uptake (VO2max), 60 min.d-1, 5 d.wk-1) on the anaerobic capacity (the maximal accumulated oxygen deficit) and VO2max was evaluated. After the training, the anaerobic capacity did not increase significantly (P > 0.10), while VO2max increased from 53 +/- 5 ml.kg-1 min-1 to 58 +/- 3 ml.kg-1.min-1 (P < 0.01) (mean +/- SD). Second, to quantify the effect of high-intensity intermittent training on energy release, seven subjects performed an intermittent training exercise 5 d.wk-1 for 6 wk. The exhaustive intermittent training consisted of seven to eight sets of 20-s exercise at an intensity of about 170% of VO2max with a 10-s rest between each bout. After the training period, VO2max increased by 7 ml.kg-1.min-1, while the anaerobic capacity increased by 28%. In conclusion, this study showed that moderate-intensity aerobic training that improves the maximal aerobic power does not change anaerobic capacity and that adequate high-intensity intermittent training may improve both anaerobic and aerobic energy supplying systems significantly, probably through imposing intensive stimuli on both systems.

Adult↗
PubMed1996

Th2 suppressor cells are more susceptible to sphingosine than Th1 cells in murine contact photosensitivity.

Murine contact photosensitivity (CPS) to 3,3',4',5-tetrachlorosalicylanilide (TCSA) is a cutaneous delayed-type hypersensitivity reaction in which both positive and negative regulatory pathways exist. The latter pathway is mediated by antigen-specific, CD4+ suppressor T cells (CPS-Ts) that are Th2 cells. We examined the effects of sphingosine and synthetic cell-permeable analogs of ceramide on the cellular kinetics of CPS-Ts and immune lymph node cells from TCSA-photosensitized mice (CPS-LNC), along with other murine T-cell populations. The addition of sphingosine at 10 or 3 microM to in vitro cultures suppressed DNA synthesis of CPS-Ts and Th2 clones, including D10 cells and 24-2 cells, but not that of CPS-LNC or Thl clones, including 23-1-8 and 28-4 cells. This suggested that sphingosine exerts its inhibitory effects preferentially on the proliferation of Th2 cells. Although suppressing DNA synthesis, sphingosine augmented the production and mRNA expression of interleukin-4 (IL-4) and enhanced the expression of the IL-4 receptor in CPS-Ts. In addition, the ability of sphingosine to induce signal transduction of CPS-Ts was confirmed by elevation of the intracellular free Ca++ concentration. Because CPS-Ts exposed to sphingosine exhibited a lower G2M/G1 ratio than control, these seemingly ambivalent phenomena may be caused by retardation of the G1 to S phase progression, a cell-cycle dysregulation known to augment cytokine production. In contrast to sphingosine, cell-permeable ceramide did not affect the proliferation of these cells when stimulated with mitogen/antigen and did not augment IL-4 production by CPS-Ts. Our study suggests that sphingosine modifies the Th1/Th2 balance by preferentially affecting the cellular kinetics of Th2.

Allergens↗
PubMed1996

Inhibitors of sphingolipid synthesis modulate interferon (IFN)-gamma-induced intercellular adhesion molecule (ICAM)-1 and human leukocyte antigen (HLA)-DR expression on cultured normal human keratinocytes: possible involvement of ceramide in biologic action of IFN-gamma.

To elucidate the participation of sphingosine and ceramide in the biologic action of cytokines on epidermal keratinocytes, we studied whether inhibitors of sphingolipid synthesis modulate interferon (IFN)-gamma-induced intercellular adhesion molecule (ICAM)-1 and human leukocyte antigen (HLA)-DR expression on cultured normal human keratinocytes. Pretreatment of keratinocytes with L-cycloserine or fumonisin B1, but not 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), significantly suppressed both ICAM-1 and HLA-DR expression induced by IFN-gamma. Because the synthesis of all kinds of sphingolipids is blocked by L-cycloserine and all except that of sphinganine by fumonisin B1, whereas PDMP inhibits the synthesis of glucosylceramide and glycosphingolipids, the result suggests the participation of ceramide and/or sphingosine in IFN-gamma-induced ICAM-1 and HLA-DR expression. Exogenous C2-ceramide reversed the effects of L-cycloserine and fumonisin B1. On the other hand, sphingosine reversed the effect of L-cycloserine, but not of fumonisin B1. These results indicate that ceramide participates in this pathway, as fumonisin B1, but not L-cycloserine, inhibits the synthesis of ceramide from sphingosine. In addition, reverse transcriptase polymerase chain reaction showed that L-cycloserine reduced the mRNA for ICAM-1, HLA-DR alpha, and HLA-DR beta induced by IFN-gamma, and C2-ceramide and sphingosine antagonized the effect of L-cycloserine. Furthermore, the degradation rate of fluorescent sphingomyelin into ceramide in keratinocytes was increased by IFN-gamma, suggesting that IFN-gamma activates sphingomyelin hydrolysis in keratinocytes. These observations suggest the possible role of ceramide in IFN-gamma-induced ICAM-1 and HLA-DR expression on keratinocytes. Ceramide may function as an endogenous modulator mediating the cytokine signals in keratinocytes.

Base Sequence↗
PubMed1996

Bladder cancer producing granulocyte colony-stimulating factor: a case report.

A rare case of bladder cancer producing granulocyte colony-stimulating factor (G-CSF) is reported. A 63-year-old man with a progressive, grade 3 transitional cell bladder carcinoma, showed marked leukocytosis (maximum 181,800/mm3) and an elevated serum G-CSF to 131.7 pg/mL. After radical cystectomy and neoadjuvant chemotherapy, the tumor recurred locally. Immunohistochemical examination with monoclonal antibody specific for G-CSF revealed positive staining in the local recurrent tumor. To our knowledge, there have been only seven cases reported of bladder cancer producing G-CSF.

Carcinoma, Transitional Cell↗