Biomedical subjects

M Kobayashi

Publications and source records attributed to M Kobayashi.

At least 577 records · Page 32Linked to original sources

PubMed2000

[Virucidal activity of disinfectants: virucidal activities of disinfectants on some viruses coated on several materials and its durability].

First, four disinfectants were tested for virucidal activity on viruses coated upon materials. Disinfectants of the aldehyde and halogen groups had a destructive effect on both enveloped and non-enveloped DNA and RNA viruses coated on a cotton gauze, stainless chips, wood shavings, polyplopylene resin chips and latex resin chips, respectively. Disinfectant of the biguanide group had a virucidal activity on both enveloped DNA and RNA viruses. Secondary, five disinfectants were tested for the durability of their virucidal activity on two DNA and RNA viruses after preparing working solutions. The disinfectants of the aldehyde group maintained their virucidal efficiency for 2 to 3 days. Disinfectants of the invert and amphoteric soap groups, the biguanide group and the halogen group maintained their virucidal efficiency for 1 to 2 days. In the presence of bovine serum, the virucidal activity of the aldehyde group and the halogen group were not influenced but that of the invert and amphoteric soap groups were strongly influenced and lost their effect.

Adenoviruses, Human↗

PubMed2000

[Virucidal activity of disinfectants. Influence of the serum protein upon the virucidal activity of disinfectants].

Five disinfectants were tested for virucidal activity on three DNA viruses and three RNA viruses in the presence or absence of serum protein. Disinfectants of the aldehyde and halogen groups had a virucidal activity on human herpes virus, bovine rhabdo virus, human immunodeficiency virus, human adeno virus, porcine parvo virus, and polio virus. Disinfectants of the invert and amphoteric soap groups, and biganide group had a destructive effect on RNA and DNA viruses possessing an envelope. The presence of serum protein exerted great influence upon the virucidal activity of disinfectants of the invert and amphoteric soap groups.

Adenoviridae↗

PubMed2000

[Serial measurement of anti-interleukin-8 IgG autoantibody in cerebrospinal fluid of infants with bacterial meningitis].

We serially measured concentrations of interleukin (IL)-8 and anti-IL-8 IgG autoantibody in cerebrospinal fluid of infants with bacterial meningitis, and also measured these concentrations in cerebrospinal fluid obtained from infants without meningitis on admission. We have reported that the IL-8 concentration in cerebrospinal fluid of infants with purulent meningitis rapidly decreases after the initiation of therapy. Thus, in the present study, the IL-8 concentration in infants with purulent meningitis only before the initiation of therapy was significantly higher compared with that in infants without meningitis. However, the concentration of anti-IL-8 IgG autoantibody was still high after the initiation of therapy. The concentration of anti-IL-8 IgG autoantibody was significantly higher compared with that in infants without meningitis until the 15th day after the initiation of therapy. The time lag between the decrease of IL-8 and anti-IL-8 IgG autoantibody demonstrated in the present study could be used to indicate the past presence of a large amount of IL-8, even if the IL-8 concentration was already low.

Autoantibodies↗

PubMed2000

Inactivation of the glutamate decarboxylase gene in Lactococcus lactis subsp. cremoris.

Lactococcus lactis subsp. lactis strains show glutamate decarboxylase activity, whereas L. lactis subsp. cremoris strains do not. The gadB gene encoding glutamate decarboxylase was detected in the L. lactis subsp. cremoris genome but was poorly expressed. Sequence analysis showed that the gene is inactivated by the frameshift mutation and encoded in a nonfunctional protein.

Base Sequence↗

PubMed2000

Interaction of recombinant norwalk virus particles with the 105-kilodalton cellular binding protein, a candidate receptor molecule for virus attachment.

Norwalk virus (NV), responsible for outbreaks of acute gastroenteritis, comprises the species of the genus Norwalk-like viruses in the family Caliciviridae. Although the study of the molecular biology of NV has been hampered by a lack of culture systems or small experimental animal models, virus-like particles (VLPs) generated with recombinant baculoviruses harboring the capsid protein gene of NV provide a useful tool for investigating NV-cell interactions. In this study, the attachment of the recombinant VLPs derived from the Ueno virus (UEV), a strain belonging to the genogroup II NVs, to mammalian and insect cells was examined. Kinetic analyses of the binding of the recombinant VLPs of the UEV (rUEVs) to Caco-2 cells demonstrated that the binding was specific and occurred in a dose-dependent manner. Approximately 7.5% of the prebound rUEVs were internalized into the Caco-2 cells. Enzymatic and chemical modification of Caco-2 cell surface molecules suggested that the binding was directly mediated by a protein-protein interaction. A virus overlay protein-binding assay (VOPBA) indicated that rUEVs appeared to bind to a 105-kDa molecule, designated as the NV attachment (NORVA) protein. Furthermore, the assay indicated that its native conformational structure was indispensable for the binding activity. In Caco-2 cells, the NORVA protein was detected when VOPBA was carried out with the VLPs from Seto and Funabashi viruses, which are serologically different NVs from UEV, used as probes. The binding of rUEVs to NORVA protein was also observed in six mammalian cell lines other than Caco-2. These data suggest that the attachment of NV to mammalian cells is mediated by NORVA protein, which is ubiquitously expressed in the mammalian cells. The present study is the first report on the role of the cellular molecule in the binding of recombinant VLPs of NV.

Amino Acid Sequence↗

PubMed2000

Cell-type-specific regulation of the retinoic acid receptor mediated by the orphan nuclear receptor TLX.

Malformations in the eye can be caused by either an excess or deficiency of retinoids. An early target gene of the retinoid metabolite, retinoic acid (RA), is that encoding one of its own receptors, the retinoic acid receptor beta (RARbeta). To better understand the mechanisms underlying this autologous regulation, we characterized the chick RARbeta2 promoter. The region surrounding the transcription start site of the avian RARbeta2 promoter is over 90% conserved with the corresponding region in mammals and confers strong RA-dependent transactivation in primary cultured embryonic retina cells. This response is selective for RAR but not retinoid X receptor-specific agonists, demonstrating a principal role for RAR(s) in retina cells. Retina cells exhibit a far higher sensitivity to RA than do fibroblasts or osteoblasts, a property we found likely due to expression of the orphan nuclear receptor TLX. Ectopic expression of TLX in fibroblasts resulted in increased sensitivity to RA induction, an effect that is conserved between chick and mammals. We have identified a cis element, the silencing element relieved by TLX (SET), within the RARbeta2 promoter region which confers TLX- and RA-dependent transactivation. These results indicate an important role for TLX in autologous regulation of the RARbeta gene in the eye.

Amino Acid Sequence↗

PubMed2000

Localisation of cyclooxygenase 1 and cyclooxygenase 2 in Helicobacter pylori related gastritis and gastric ulcer tissues in humans.

BACKGROUND: Prostaglandin endoperoxide synthase/cyclooxygenase (COX) is the key enzyme in gastric mucosal protection and repair but its cellular localisation in the human stomach is still unclear. AIMS: To investigate immunohistochemically the cellular distribution of COX-1 and COX-2 proteins in the human stomach with or without gastritis or ulceration. PATIENTS AND METHODS: Tissues were obtained by surgical resection of gastric ulcers associated with perforation (n = 9) or by biopsy from Helicobacter pylori positive patients with gastric ulcers (n = 45) and H pylori negative healthy subjects (n = 15). COX expression was detected by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), western blotting, and light and electron microscopic immunohistochemistry. RESULTS: COX-2 mRNA and protein were detected in gastric ulcer tissues but not in intact gastric mucosa. COX-1 mRNA and protein were detected in the intact mucosa. COX-2 immunostaining was exclusively localised in macrophages and fibroblasts between necrotic and granulation tissues of the ulcer bed. The percentage of COX-2 expressing cells was significantly higher in open than in closed ulcers, and in gastritis than in gastric mucosa without H pylori infection. COX-1 immunoreactivity localised in lamina propria mesenchymal cells was similar in various stages of ulcer disease and in intact gastric mucosa. Electron microscopic immunohistochemistry revealed both COX-1 and COX-2 on the luminal surfaces of the endoplasmic reticulum and nuclear envelope of macrophages and fibroblasts. CONCLUSIONS: Our results showed that COX-2 protein was induced in macrophages and fibroblasts in gastric ulcers and H pylori related gastritis, suggesting its involvement in the tissue repair process.

Adult↗

PubMed2000

Primary structures of PYY, [Pro(34)]PYY, and PYY-(3-36) confer different conformations and receptor selectivity.

We synthesized PYY-(1-36) (nonselective between Y(1) and Y(2) receptor subtype agonists), [Pro(34)]PYY (selective for Y(1)), and PYY-(3-36) (selective for Y(2)) to determine whether solution conformation plays a role in receptor subtype selectivity. The three peptides exhibited the expected specificities in displacing labeled PYY-(1-36) from cells transfected with Y(1) receptors (dissociation constants = 0.42, 0.21, and 1,050 nM, respectively) and from cells transfected with Y(2) receptors (dissociation constants = 0.03, 710, and 0.11 nM, respectively) for PYY-(1-36), [Pro(34)]PYY, and PYY-(3-36). Sedimentation equilibrium analyses revealed that the three PYY analogs were 80-90% monomer at the concentrations used for the subsequent circular dichroism (CD) and (1)H-nuclear magnetic resonance (NMR) studies. CD analysis measured helicities for PYY-(1-36), [Pro(34)]PYY, and PYY-(3-36) of 42%, 31%, and 24%, suggesting distinct differences in secondary structure. The backbone (1)H-NMR resonances of the three peptides further substantiated marked conformational differences. These patterns support the hypothesis that Y(1) and Y(2) receptor subtype binding affinities depend on the secondary and tertiary solution state structures of PYY and its analogs.

Amino Acid Sequence↗

PubMed2000

Inhibition of baroreflex vagal bradycardia by activation of the rostral ventrolateral medulla in rats.

In stressful conditions, baroreflex vagal bradycardia (BVB) is often suppressed while blood pressure is increased. To address the role of the rostral ventrolateral medulla (RVL), a principal source of sympathetic tone, in inhibition of BVB, we microinjected DL-homocysteic acid (DLH, 6 nmol) into the RVL of chloralose-urethan-anesthetized, sinoaortic-denervated rats to examine the effect on BVB. The BVB was provoked by electrical stimulation of the aortic depressor nerve ipsilateral to the injection sites. DLH microinjection was found to suppress BVB while increasing blood pressure. The inhibition of BVB was observed even during the early phase in which DLH transiently suppressed central inspiratory activity. The inhibition was not affected either by upper spinal cord transection or suprapontine decerebration. Similar results were obtained by microinjection of bicuculline methiodide (160 pmol), a GABA antagonist, into the RVL of carotid sinus nerve-preserved rats due to withdrawal of a tonic GABA-mediated, inhibitory influence including the input from arterial baroreceptors. In conclusion, activation of the RVL inhibits BVB at brain stem level independently of central inspiratory drive.

Animals↗

PubMed2000

Relationship between five-year histological outcome and serial changes in serum alanine aminotransferase in patients with biochemical and virological relapse after interferon treatment for chronic hepatitis C.

OBJECTIVE: The aim of this study was to assess the correlation between serial changes in serum alanine aminotransferase (ALT) levels and histological outcome 5 years after treatment of patients with chronic hepatitis C with interferon (IFN). METHODS: We retrospectively evaluated 61 consecutive patients who underwent two liver biopsies, just before and 5 years after a 6-month course of IFN therapy, and who showed a relapse after therapy. The extent of liver fibrosis was estimated using a scale with seven grades. RESULTS: At the end of 6-month IFN therapy, 40 (65.6%) patients had normal serum ALT concentrations. However, 13 of the 40 patients relapsed within 6 months after IFN therapy. The average ALT during 5 years in 40 patients was less than or equal to 75 IU/l, while in the other 21 patients it was more than 75 IU/l. Among the 40 patients with a mean ALT less than 75 IU/l, 13 (33%) patients showed histological improvement, 26 (65%) showed no changes and only 1 patient (2%) showed worsening of liver fibrosis. On the other hand, among the 21 patients with a mean ALT of more than 75 IU/l, only 1 (5%) patient showed improvement, 8 (38%) showed no changes and 12 patients (57%) showed worsening of liver fibrosis. CONCLUSION: There is a significant relationship between 5-year histological outcome and serial changes in serum ALT in patients with biochemical and virological relapse after IFN treatment for chronic hepatitis C.

Adult↗

PubMed2000

Costello syndrome with decreased gene expression of elastin in cultured dermal fibroblasts.

We report a case of Costello syndrome. A 2-year-old Japanese boy presented with a 'coarse' face, curly hair and loose skin of the dorsal aspect of the hands and feet with dark pigmentation. A skin biopsy of the dorsal aspect of the left hand revealed hyperkeratosis and papillomatosis of the epidermis, hyperpigmentation of the basal layer, and shortening and rupture of elastic fibers of the dermis. Electron microscopy of dermal elastic fibers showed a decreased amount of elastin with an exposed appearance of microfibrils. In Northern blot analysis of cultured dermal fibroblasts, elastin mRNA levels were reduced, suggesting a decrease in elastin production at the lesions of loose skin.

Abnormalities, Multiple↗

PubMed2000

Flow-mediated vasodilation and plasma fibronectin levels in preeclampsia.

To clarify the vascular endothelial function in pregnant women with hypertensive disorders, we assessed the flow-mediated vasodilation in the radial artery and compared it with plasma fibronectin levels. We determined flow-mediated vasodilation by measuring the change in radial artery diameter during hyperemia in 58 normal pregnant women, 22 preeclamptic pregnant women, and 15 pregnant women with chronic hypertension. In 41 of the 95 pregnant women, we measured the plasma fibronectin levels. Flow-mediated vasodilation in preeclamptic women was significantly less than that in normal pregnant women (P:<0.001). In chronic hypertensive women, flow-mediated vasodilation was significantly less than that in normal pregnant women (P:<0.001) but more than that in preeclamptic women (P:<0.001). Flow-mediated vasodilation showed significant negative correlation with plasma fibronectin levels (P:<0.001, r=0.73). Our results indicate that the endothelial function can be noninvasively assessed in pregnant women with hypertensive disorders by measuring the flow-mediated vasodilation of the radial artery with high-resolution ultrasound.

Adult↗

PubMed2000

Deteriorating ischemic stroke in 4 clinical categories classified by the Oxfordshire Community Stroke Project.

BACKGROUND AND PURPOSE: The aim of this study was to investigate the frequency, possible predictive factors, and prognosis of deteriorating ischemic stroke in 4 clinical categories according to the classification of the Oxfordshire Community Stroke Project (OCSP). METHODS: A total of 350 patients with first-ever ischemic stroke who presented within 24 hours of onset were enrolled. Based on the OCSP criteria, cerebral infarctions were divided into the following 4 clinical categories: total anterior circulation infarcts (TACI), partial anterior circulation infarcts (PACI), lacunar infarcts (LACI), and posterior circulation infarcts (POCI). Clinical deterioration was defined as a decrease of >/=1 points in the Canadian Neurological Scale (CNS) (in TACI, PACI, and LACI) or Rankin Scale (RS) (in POCI) during 7 days from the onset. In each clinical category, deteriorating (D) and nondeteriorating (ND) patients were compared in terms of their background characteristics, risk factors, vital signs, laboratory data, and cranial CT at the time of hospitalization. The acute-phase mortality and functional outcome were also compared. RESULTS: The subjects comprised 86 patients (24.6%) with TACI, 63 (18.0%) with PACI, 141 (40.3%) with LACI, and 60 (17.1%) with POCI. Overall, 90 patients (25.7%) deteriorated. The frequency was very high in TACI (41.9%), followed by LACI (26.2%) and POCI (21.7%), whereas it was very low in PACI (6. 3%). There were some clinical variables that differed significantly between D and ND groups. In the patients with TACI, early abnormalities of the cranial CT and significant stenoses in corresponding arteries were more frequent in the D than the ND group. In those with LACI, the CNS and hematocrit were lower in the D than the ND group. In those with POCI, cerebral atrophy was more severe and significant stenoses in vertebrobasilar arteries were more frequent in the D than ND group. The mortality of the D groups of patients with TACI and POCI exceeded 35%, and the functional outcome was worse in the D group than in the ND group of patients with TACI, LACI, and POCI. CONCLUSIONS: The frequency of deterioration in acute ischemic stroke significantly differed among the OCSP subgroups, and deterioration worsened the prognosis. There were some factors that could predict deterioration: early CT findings in TACI, large-artery atherosclerosis in TACI and POCI, and stroke severity in LACI. Further research to find sophisticated radiological and chemical markers appears to be needed.

Acute Disease↗

PubMed2000

Effects of antigen-retrieval pretreatments for immunohistochemical detection of Akabane viral antigen.

Effects of various antigen-retrieval pretreatment techniques for immunohistochemical detection of Akabane virus antigen were examined with formalin-fixed, paraffin-embedded tissues taken from mice intracerebrally inoculated with the virus. The results indicated that no pretreatment is necessary for the detection of the antigen, and excessive enzymatic pretreatment of sections may lead to false-negative results.

Animals↗

PubMed2000

Foods and nutrients in relation to bladder cancer risk: a case-control study in Aichi Prefecture, Central Japan.

To elucidate the role of diet in the etiology of bladder cancer, we conducted a case-control study from 1996 to 1999 in Aichi Prefecture, Central Japan. Cases were patients newly diagnosed with bladder cancer, and one hospital control was selected for each case, matching gender, age, and hospital. A well-validated food frequency questionnaire was adopted to estimate intakes of nutrients and food groups. Odds ratios (ORs) adjusted for smoking and occupational history were computed using conditional logistic models. The analyses based on 297 cases and 295 controls revealed the following. 1) The more the intake of milk and dairy products, the lower the OR; the ORs across quartiles in all subjects were 1.02, 0.73, and 0.52. Fruit intake was negatively associated with the risk, particularly in men (ORs across quartiles = 0.76, 0.77, and 0.52). Green-yellow vegetables were associated with a decreased risk in the highest quartile of consumption in men (OR = 0.57). 2) Dietary intakes of retinol and saturated fatty acids were related to a reduced risk in all subjects (ORs across quartiles = 0.75, 0.54, and 0.66 and 0.55, 0.54, and 0.60, respectively). Monounsaturated fatty acids had an inverse association with bladder cancer risk in men.

Adult↗

PubMed2000

A rapamycin-sensitive pathway down-regulates insulin signaling via phosphorylation and proteasomal degradation of insulin receptor substrate-1.

Insulin receptor substrate-1 (IRS-1) is a major substrate of the insulin receptor and acts as a docking protein for Src homology 2 domain containing signaling molecules that mediate many of the pleiotropic actions of insulin. Insulin stimulation elicits serine/threonine phosphorylation of IRS-1, which produces a mobility shift on SDS-PAGE, followed by degradation of IRS-1 after prolonged stimulation. We investigated the molecular mechanisms and the functional consequences of these phenomena in 3T3-L1 adipocytes. PI 3-kinase inhibitors or rapamycin, but not the MEK inhibitor, blocked both the insulin-induced electrophoretic mobility shift and degradation of IRS-1. Adenovirus-mediated expression of a membrane-targeted form of the p110 subunit of phosphatidylinositol (PI) 3-kinase (p110CAAX) induced a mobility shift and degradation of IRS-1, both of which were inhibited by rapamycin. Lactacystin, a specific proteasome inhibitor, inhibited insulin-induced degradation of IRS-1 without any effect on its electrophoretic mobility. Inhibition of the mobility shift did not significantly affect tyrosine phosphorylation of IRS-1 or downstream insulin signaling. In contrast, blockade of IRS-1 degradation resulted in sustained activation of Akt, p70 S6 kinase, and mitogen-activated protein (MAP) kinase during prolonged insulin treatment. These results indicate that insulin-induced serine/threonine phosphorylation and degradation of IRS-1 are mediated by a rapamycin-sensitive pathway, which is downstream of PI 3-kinase and independent of ras/MAP kinase. The pathway leads to degradation of IRS-1 by the proteasome, which plays a major role in down-regulation of certain insulin actions during prolonged stimulation.

3T3 Cells↗

PubMed2000

Effects of dosing time and schedule on cisplatin-induced nephrotoxicity in rats.

Renal dysfunction induced by a single injection of cisplatin depends on the timing of the dose. However, the effects of repeated administration of cisplatin on time-dependent toxicity have not been evaluated despite the fact that in clinical practice high doses are repeatedly injected at intervals or low doses are administered daily. We studied chrononephrotoxicity in rats after weekly or daily cisplatin injections. Weekly high doses (5 mg kg(-1)) or daily low doses (1.2 mg kg(-1)) of cisplatin were injected at four time points (3, 9, 15 and 21 h after the light was turned on (HALO)) for 3 weeks. Changes in body weight after weekly cisplatin administration were independent of the timing of the doses. In the group that received daily cisplatin, the loss in body weight in the 3 HALO group was smaller than in animals receiving injections at 15 and 21 HALO (P < 0.05 and 0.001, respectively). The blood urea nitrogen and serum creatinine levels in the control rats showed a significant circadian change (peak at 15 HALO and trough at 9 HALO), but these parameters were markedly elevated in both trials and their circadian variations were disturbed. In conclusion, cisplatin-induced nephrotoxicity was the lowest at 3HALO compared with other time points of both dose regimens.

Animals↗

PubMed2000

Direct identification of a novel disulfide bond linkage system of new isolated isomer (isomer V) in recombinantly produced h-IGF-I.

Insulin-like growth factor I (IGF-I or somatomedin C) is a serum polypeptide with three intramolecular disulfide bonds. In the course of synthesis by the recombinant DNA method, three disulfide bond isomers, all of which have Cys18-Cys61 with three combinations of two disulfide bonds formed by Cys6, Cys47, Cys48 and Cys52, were identified. Natural type, isomer II, was proved to have a Cys6-Cys48, Cys18-Cys61, Cys47-Cys52 disulfide bond system. Now, the fourth isomer, isomer V which doesn't have Cys18-Cys61 disulfide, has been isolated, and its novel disulfide bond linkage system was identified by a chemical synthetic method. The supposed conformation constrained in 3D structure for isomer V would be discussed for its biological activity.

3T3 Cells↗