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Biomedical subjects

J Kobayashi

Publications and source records attributed to J Kobayashi.

At least 127 records · Page 7Linked to original sources
PubMed2000

Comparative studies on the efficacy of three anthelminthics on treatment of human strongyloidiasis in Okinawa, Japan.

A study was undertaken to compare the efficacy of three drugs in the treatment of uncomplicated strongyloidiasis in Okinawa, Japan. Two hundred and eleven patients with confirmed Strongyloides stercoralis infection were given either ivermectin, 6 mg in a single dose, albendazole, 400 mg/day for 3 days or pyrvinium pamoate, 5 mg/kg/day for 3 days. For each treatment, the same regimen was repeated once 2 weeks later. Efficacy was evaluated at 2 weeks, 6 months and 12 months after the second course of treatment. Each follow-up examination included a parasitological examination of z stool specimens, using the agar-plate culture method. Coprological cure was obtained in 65 of the 67 patients treated with ivermectin (97.0%), in 65 of the 84 patients treated with albendazole (77.4%) and only in 14 of the 60 patients who were given pyrvinium pamoate (23.3%). The cure rates were lower in males and in the patients with concurrent HTLV-1 infection. An epidemiological feature of Strongyloides infection in recent Okinawa might allow workers to evaluate the exact efficacy of the treatment for an extended period, over a year, without the possibility of reinfection from the environment.

Adult↗
PubMed2000

A new sandwich enzyme immunoassay for measurement of plasma pre-beta1-HDL levels.

Pre-beta1-HDL, a putative discoid-shaped high density lipoprotein (HDL) of approximately 67-kDa mass that migrates with pre-beta mobility in agarose gel electrophoresis, contains apolipoprotein A-I (apoA-I), phospholipids, and unesterified cholesterol. It participates in the retrieval of cholesterol from peripheral tissues. In this study we established a new sandwich enzyme immunoassay (EIA) for measuring plasma pre-beta1-HDL using mouse anti-human pre-beta1-HDL monoclonal antibody (MAb 55201) and goat anti-human apoA-I polyclonal antibody. MAb 55201 reacted with apoA-I in lipoprotein [A-I] with molecular mass less than 67 kDa, and with pre-beta1-HDL separated by nondenaturing two-dimensional electrophoresis, whereas it did not react with apoA-I in alpha-HDL. Pre-beta1-HDL levels measured by this method declined when incubated at 37 degrees C for 2 h, whereas this decrease was not observed in the presence of 2 mM lecithin:cholesterol acyltransferase inhibitor 5,5'-dithiobis (2-nitrobenzoic acid). To clarify the clinical significance of measuring pre-beta1-HDL by this method, 47 hyperlipidemic subjects [male/female 22/25; age 55 +/- 14 years; body mass index 25 +/- 4.5 kg/m(2); total cholesterol (TC) 245 +/- 64 mg/dl; triglyceride (TG) 232 +/- 280 mg/dl; HDL cholesterol (HDL-C) 51 +/- 23 mg/dl] and 25 volunteers (male/female 15/10; age 36 +/- 9.3 years; body mass index 23 +/- 3.5 kg/m(2); TC 183 +/- 28 mg/dl; TG 80 +/- 34 mg/dl; HDL-C 62 +/- 15 mg/dl) were involved. Plasma pre-beta1-HDL levels were significantly higher in hyperlipidemic subjects than in volunteers (39.3 +/- 10.1 vs. 22.5 +/- 7.5 mg/ml, P < 0.001) whereas plasma apoA-I levels did not differ (144.2 +/- 28.4 vs. 145.3 +/- 16.3 mg/dl). These results indicate that this sandwich EIA method specifically recognizes apoA-I associated with pre-beta1-HDL.

Adult↗
PubMed2000

Community control studies on Strongyloides infection in a model island of Okinawa, Japan.

The community control program for Strongyloides infection was conducted by fecal examination and subsequent treatment of the population on a model island (Kume Island) in Okinawa, Japan, for 5 years from 1993 to 1997. More than 1,200 persons, accounting for 17% to 20% of the persons subjected, received fecal examinations each year. The positive rate in 1993 was found to be 9.7% (133/1,374). The positive rate decreased to 6.5% (95/1,468) in 1994, then 4.8% (60/1,245) in 1995, 2.2% (27/1,225) in 1996 and 2.7% (33/1,217) in 1997 through treatment with albendazole or ivermectin on the positive persons detected each year. Among the positive persons detected after operation of the control program, more than 70% were newly detected persons who did not receive an examination in the previous year or were falsely-negative in the previous examination. The low enforcement of procuring fecal examinations, as well as low sensitivity of fecal examination, might have had an effect on the relatively gradual decrease in the prevalence rate, in spite of the high efficacy of the treatment. The results indicate that continuation of the control program for several years is needed to effectively reduce the prevalence of the parasitic infection in the community.

Adult↗
PubMed1999

Expression of full-length NBS1 protein restores normal radiation responses in cells from Nijmegen breakage syndrome patients.

Cells from Nijmegen breakage syndrome (NBS) display multiple phenotypes, such as chromosomal instability, hypersensitivity to cell killing from ionizing radiation, and possibly abnormal cell cycle checkpoints. NBS1, a gene mutated in NBS patients, appears to encode a possible repair protein, which could form the foci of a sensor-like molecular complex capable of detecting DNA double strand breaks, however, it has no kinase domain for signaling DNA damage. Here, we report that the stable expression of NBS1 cDNA in NBS cells after transfection results in the complete restoration of foci formation in the nucleus, and in normal cell survival after irradiation. The prolonged G2 block observed after irradiation was also abolished by expression of NBS1, providing additional confirmation that the G2 checkpoint is abrogated in NBS cells. These results suggest that a defective NBS1 protein could be the sole cause of the NBS phenotype, and that NBS1 likely interacts with another protein(s) to produce the entire range of NBS phenotypic expression.

Base Sequence↗
PubMed1999

Fluorescence in situ hybridization with Y chromosome-specific probe in decondensed bovine spermatozoa.

This study was carried out to demonstrate bovine Y chromosome-bearing spermatozoa by rapid fluorescence in situ hybridization (FISH), using a digoxigenin (Dig)-labeled DNA probe specific to bovine Y chromosome. Before the FISH procedure, sperm heads were treated for decondensation with dithiothreitol (DTT) and glutathione (GSH) with or without heparin supplementation. Concentrations of either above 2 mM DTT or above 100 mM GSH induced swelling of the sperm head, which resulted in sufficient detection of the Y chromosome signal in sperm nuclei by rapid FISH (49.8 to 53.4%). When FISH was used with 2 mM DTT or 100 mM GSH on specimens from 7 sires, the rate of detection of the Y chromosome signal varied among sires (5.4 to 49.6%), especially that of the GSH treatment. Supplementation of GSH with heparin (100 U/mL), however, could induce reliable, repeatable detection of the Y chromosome signal in sperm nuclei of all the 7 sires (48.4 to 50.3%). These results show that in bovine spermatozoa decondensed with GSH and heparin, rapid FISH can detect Y chromosome-bearing spermatozoa.

Animals↗
PubMed1999

Reactive oxygen species as a risk factor in verotoxin-1-exposed rats.

It has been suggested the the interaction of Escherichia coli O157-derived verotoxins (VTs) with the vascular endothelium plays a central role in the pathogenesis of the thrombotic microangiopathy and ischemic lesions characteristic of hemolytic uremic syndrome (HUS) and E. coli O157-associated hemorrhagic colitis. Intravenous administration of both E. coli O157-derived VT1 and lipopolysaccharide (LPS) in the rat induced a synergistic increase in thiobarbituric acid (TBA) values in those animal's plasma, as compared with that injected with VT1 or LPS alone. We then hypothesized that an increase in lipid peroxidation in the rat plasma was due to an enhanced production of endothelial cell-derived reactive oxidant. Based on determination of rat sera and cultured human aortic endothelial cells (HAECs), VT1 had little if any effect on LPS-stimulated increase of nitric oxide and the resultant peroxynitrite generations. Both RT-PCR and Western blot studies of reactive oxygen species-related enzymes showed that VT1 markedly decreased the expression of catalase mRNA and protein in HAECs, but caused less alteration in the levels of Cu, Zn-superoxide dismutase, and NADPH oxidase mRNA. Further studies by spin trapping analysis using 5, 5-dimethyl-1-pyrroline-N-oxide (DMPO) revealed a time-dependent increase in hydroxyl radicals by VT1 in HAECs. The accumulated data thus suggest that bacterial VT1 reduces mainly catalase levels in endothelial cells, which is synergistically potentiated by LPS, and that the resulting hydroxyl radical participates in endothelium injury through a marked enhancement of lipid peroxidation, leading to HUS.

Animals↗
PubMed1999

Amphidinolide B, a powerful activator of actomyosin ATPase enhances skeletal muscle contraction.

Amphidinolide B caused a concentration-dependent increase in the contractile force of skeletal muscle skinned fibers. The concentration-contractile response curve for external Ca2+ was shifted to the left in a parallel manner, suggesting an increase in Ca2+ sensitivity. Amphidinolide B stimulated the superprecipitation of natural actomyosin. The maximum response of natural actomyosin to Ca2+ in superprecipitation was enhanced by it. Amphidinolide B increased the ATPase activity of myofibrils and natural actomyosin. The ATPase activity of actomyosin reconstituted from actin and myosin was enhanced in a concentration-dependent manner in the presence or absence of troponin-tropomyosin complex. Ca2+-, K+-EDTA- or Mg2+-ATPase of myosin was not affected by amphidinolide B. These results suggest that amphidinolide B enhances an interaction of actin and myosin directly and increases Ca2+ sensitivity of the contractile apparatus mediated through troponin-tropomyosin system, resulting in an increase in the ATPase activity of actomyosin and thus enhances the contractile response of myofilament.

Actomyosin↗
PubMed1999

Modulation of multidrug resistance in tumor cells by taxinine derivatives.

Among a series of taxinine (1) and its designed derivatives (2-33), two taxoids (29 and 33) increased cellular accumulation of vincristine in multidrug-resistant tumor cells more potently than verapamil, while the activities of eight taxoids (11, 14-16, 22, and 30-32) were comparable with that of verapamil. These results reveal that some taxinine derivatives are good modifiers of multidrug resistance in tumor cells.

Animals↗
PubMed1999

An outbreak of Escherichia coli O157:H7 infection from unpasteurized commercial apple juice.

BACKGROUND: Escherichia coli O157:H7 infections have traditionally been associated with animal products, but outbreaks associated with produce have been reported with increasing frequency. In fall 1996, a small cluster of E. coli O157:H7 infections was epidemiologically linked to a particular brand (brand A) of unpasteurized apple juice. OBJECTIVE: To define the extent of the outbreak, confirm the source, and determine how the apple juice became contaminated. DESIGN: Descriptive epidemiologic study and traceback investigation. SETTING: Western United States and British Columbia, Canada. PATIENTS: Patients with E. coli O157:H7 infection who were exposed to brand A apple juice. MEASUREMENTS: Clinical outcome and juice exposure histories of case-patients, pulsed-field gel electrophoresis of case and juice isolates, and juice production practices. RESULTS: Seventy persons with E. coli O157:H7 infection and exposure to brand A unpasteurized apple juice were identified. Of these persons, 25 (36%) were hospitalized, 14 (20%) developed the hemolytic uremic syndrome, and 1 (1%) died. Recalled apple juice that was produced on 7 October 1996 grew E. coli O157:H7 with a pulsed-field gel electrophoresis pattern indistinguishable from that of case isolates. Apple juice produced on 7 October 1996 accounted for almost all of the cases, and the source of contamination was suspected to be incoming apples. Three lots of apples could explain contamination of the juice: Two lots originated from an orchard frequented by deer that were subsequently shown to carry E. coli O157:H7, and one lot contained decayed apples that had been waxed. CONCLUSIONS: Standard procedures at a state-of-the-art plant that produced unpasteurized juices were inadequate to eliminate contamination with E. coli O157:H7. This outbreak demonstrated that unpasteurized juices must be considered a potentially hazardous food and led to widespread changes in the fresh juice industry.

Adolescent↗
PubMed1999

Correlation of anatomic and hemodynamic features with aortic valve leaflet deformity in doubly committed subarterial ventricular septal defect.

The records of 153 patients with doubly committed subarterial ventricular septal defect (DCVSD) who underwent intracardiac repair were analyzed to evaluate factors responsible for aortic valve leaflet deformity. The patients were divided into two groups according to their echocardiographic and angiographic features as well as anatomic findings at operation: DCVSD without (17/153, 11.1%) and with arterial valve offsetting (136/153, 88.9%). Aortic regurgitation (AR) was much more prevalent in the patients with (50.0%) than in those without leaflet deformity (2.2%, P < 0.01). Arterial valve offsetting is one of the major contributing factors to the development of leaflet deformity, accounting for 5.9% in the patients without offsetting and 46.3% in those with offsetting (P < 0.01). Among the patients with arterial valve offsetting, the pulmonary-to-systemic pressure ratio was significantly higher (P < 0.01) in the patients without (0.76 +/- 0.14) than in those with leaflet deformity (0.36 +/- 0.12), suggesting that pulmonary hypertension might prevent the aortic valve leaflet from prolapsing in DCVSD. In addition, increased severity of aortic valve leaflet deformity and subsequent AR were observed with increasing age. These results suggest that aging and the presence of arterial valve offsetting as well as the absence of pulmonary hypertension might be factors responsible for aortic valve leaflet deformity and subsequent AR in DCVSD. The anatomic and hemodynamic features in DCVSD have a great impact on the development of aortic valve leaflet deformity and subsequent AR.

Adolescent↗
PubMed1999

A novel frameshift mutation in exon 6 (the site of Asn 291) of the lipoprotein lipase gene in type I hyperlipidemia.

A new heterozygous lipoprotein lipase gene defect has been identified in a type I hyperlipidemic patient at the position of notable amino acid Asn 291. The patient is a 33-year-old male. His body mass index (BMI) was 18.5 kg/m2. The total cholesterol (TC), triglycerides (TG) and high density lipoprotein-cholesterol (HDL-C) concentration from his fasting plasma were 4.8, 11.9 and 0.4 mmol/l, respectively. The lipoprotein lipase (LPL) activity and mass in the postheparin plasma (PHP) from the patient were 0.58 mmol/ml/h (normal range: 7.7+/-2.6) and 244 ng/ml (normal range: 192+/-30), respectively. The hepatic lipase activity of the PHP from the patient was 10.6 mmol/ml/h (normal range: 9.9+/-3.6). DNA analysis of the LPL gene revealed that this patient had a heterozygous one nucleotide deletion of A coding Asn 291, resulting in a premature termination of the LPL protein at amino acid residue 303. The other abnormality in the LPL gene of the proband was an amino acid residue 194 defect (Ile194-->Thr), which is known to cause a defective enzyme. A medium-chain triglyceride (MCT) loading test was conducted to find how this triglyceride affects plasma lipoprotein metabolism in this patient in a short term (Fig. 3). The plasma total cholesterol (TC) or high density lipoprotein (HDL)-C levels did not change significantly after oral administration of a fatty meal containing long chain triglycerides (LCT) or MCT. The plasma TG level, on the other hand, increased from 11.9 to 19.2 mmol/l (+61%) at 6 h after loading a fatty meal containing LCT, whereas the plasma TG levels tended to even decrease at 6 h after oral administration of an MCT, tricaprin (from 11.6 to 10.5 mmol/l (-9.4%)). These results suggest that MCT, as opposed to LCT, is useful for treatment of type I hyperlipidemia with a novel mutation at the notable amino acid Asn 291 of the LPL gene.

Adult↗
PubMed1999

Claudin-1 contributes to the epithelial barrier function in MDCK cells.

Tight junctions (TJs) create a paracellular permeability barrier and also act as a fence preventing intermixing of proteins and lipids between the apical and basolateral plasma membranes. Recently, claudin-1 has been identified as an integral membrane protein localizing at TJs, and introduced claudin-1 can form TJ-like networks in fibroblasts. To investigate the function of claudin-1, MDCK cells were transfected with a mammalian expression vector containing myc-tagged mouse claudin-1, and four stable clones were obtained. The myc-tagged claudin-1 precisely colocalized with both occludin and ZO-1 at cell-cell contact sites, indicating that exogenous claudin-1 was properly targeted to the TJs. Immunoblot analysis revealed that overexpression of claudin-1 increased expression of ZO-1 but not of occludin or ZO-2. The barrier functions of these cells were evaluated by transepithelial electrical resistance (TER) and paracellular flux. Claudin-1-expressing cells exhibited about four times higher TER than wild-type MDCK cells. Consistent with the increase of TER, the cells overexpressing claudin-1 showed reduced paracellular flux, estimated at 4 and 40 kD FITC-dextrans. These results suggest that claudin-1 is involved in the barrier function at TJs.

Animals↗
PubMed1999

Effect of FR167653 on small bowel ischemia-reperfusion injury in dogs.

IL-1 and TNF-alpha are known to be pleiotropic cytokines associated with various inflammatory conditions such as small intestinal injury after ischemia-reperfusion. FR167653 has been characterized as a potent suppressant of IL-1 and TNF-alpha production. The effect of FR167653 on intestinal reperfusion injury was investigated in a warm ischemia model of the canine gut. Sixteen mongrel dogs were divided into two groups: a control group and a FR group to which FR167653 was administered. Both the superior mesenteric artery and vein were clamped for 2 hr. Arterial pH, hepatic venous hemoglobin oxygen saturation, intramucosal pH, and the survival rate were well maintained in the FR group in comparison with the control group after reperfusion. FR167653 inhibited the expression of IL-1beta mRNA. Histologically, ischemia-reperfusion injury was more severe in the control group than the FR group. This study suggests that FR167653 inhibits proinflammatory cytokines and ameliorates ischemia-reperfusion injury of the small intestine.

Animals↗
PubMed1999

Effect of troglitazone on plasma lipid metabolism and lipoprotein lipase.

AIMS: To clarify how troglitazone, an insulin-sensitizing agent, affects lipid metabolism and postheparin plasma lipoprotein lipase (LPL). METHODS: Fifteen patients (3 male, 12 female) (the average age 62+/-7 years; the mean body mass index (BMI) 25+/-3 kg/m2 ) were recruited for this study. The serum lipids and postheparin plasma lipoprotein lipase (LPL) mass before and 4 weeks after oral administration of troglitazone (200 mg day-1 ) were measured. A mouse preadipocyte cell line, 3T3-L1, was incubated with troglitazone and LPL enzyme protein mass in the culture media was measured by an enzyme linked immunosorbent assay. A reverse transcription polymerase chain reaction (RT-PCR) using primers specific for the carboxyl terminal 135 amino acid of mouse LPL cDNA was used to evaluate the effect of troglitazone on expression of LPL and Northern blot analysis carried out to determine expression of LPL. RESULTS: The average levels before treatment of fasting serum total cholesterol, triglycerides, high density lipoprotein cholesterol, plasma glucose and glycohaemoglobin A1c were 5.6+/-0.9, 1.8+/-1.0, 1.5+/-0.5, 8.1+/-1.7 mmol l-1 and 7.8+/-1.6% respectively. Four weeks after treatment, those levels were 5.4+/-0.9, 1.2+/-0.3 (P=0.004), 1.6+/-0.5 (P=0.02) mmol l-1, 7.7+/-2.3 mmol l-1 and 7. 3+/-0.6% (P=0.01), respectively. The postheparin plasma LPL mass increased from 226+/-39 to 257+/-68 ng ml-1 (P=0.03) during that period. The LPL mass in the media of 3T3 L1 cells cultured in the presence of 10, 20 or 30 microm of this compound increased in a dose dependent manner. RT-PCR revealed that the area of the bands of the RT-PCR products on 1.5% agarose gel analyzed with NIH image from the cell extracts cultured in the presence of 10 microm troglitazone was significantly larger (P=0.0069) than that in the absence of this compound. Northern blot analysis revealed that in the cultured 3T3-L1 cells, the expression of LPL was enhanced in the presence of 10 microm troglitazone. CONCLUSIONS: Troglitazone improves plasma triglyceride-rich lipoproteins metabolism by enhancing the expression of LPL in adipocytes.

3T3 Cells↗