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Biomedical subjects

J Kobayashi

Publications and source records attributed to J Kobayashi.

At least 19 recordsLinked to original sources
PubMed1995

Structure-activity relationship of bromoeudistomin D, a powerful Ca2+ releaser in skeletal muscle sarcoplasmic reticulum.

Bromoeudistomin D and 9-methyl-7-bromoeudistomin D which have a beta-carboline skeleton are powerful Ca2+ releasers from skeletal muscle sarcoplasmic reticulum exhibiting caffeine-like properties. We examined the effects of bromoeudistomin D analogues on Ca(2+)-induced Ca2+ release from skeletal muscle sarcoplasmic reticulum. Among bromoeudistomin D analogues, the Ca(2+)-releasing activities of carboline derivatives were higher than those of carbazole derivatives, suggesting that a carboline skeleton is significantly important for the manifestation of Ca(2+)-releasing activity and Ca2+ sensitivity of Ca(2+)-induced Ca2+ release. On the contrary, the analogues which have a carbazole skeleton and bromine at C-6 inhibit both Ca(2+)- and caffeine-induced Ca2+ release. 9-Methyl-substitution of the analogue elevated its Ca(2+)-releasing activity. Moreover, there is a close correlation between the enhancement of [3H]ryanodine binding to sarcoplasmic reticulum by the analogues and the activation of Ca2+ release by them. Bromoudistomin D analogues may provide valuable information about the structure-function relationship of the ryanodine receptor/Ca2+ release channels in skeletal muscle sarcoplasmic reticulum.

Animals↗
PubMed1995

Reduced dimerization of lipoprotein lipase in post-heparin plasma of a patient with hyperchylomicronemia.

As in post-heparin plasma of control subjects, post-heparin plasma of a patient with hyperchylomicronemia contained lipoprotein lipase (LPL) subunits with M(r) = 57,000. But although the amount of LPL was the same as in post-heparin plasma of controls, no LPL activity was detectable. Nearly all the LPL in post-heparin plasma of controls bound to heparin-Sepharose and this LPL bound was mainly eluted with 1.5 M NaCl in parallel with the activity. In post-heparin plasma of the patient, 58% of the LPL subunits did not bind to heparin-Sepharose and 23% was eluted with 0.6 M NaCl. Studies by sucrose density gradient centrifugation showed that almost all the LPL in post-heparin plasma of controls was recovered in the peak with a sedimentation coefficient of 6.8 S, corresponding to the position of a dimeric form of LPL, in parallel with the activity; little LPL was recovered in the peak with a sedimentation coefficient of 4.0 S, corresponding to the position of a monomeric form of LPL. In post-heparin plasma of the patient, 35% of the LPL subunits was recovered in fractions with larger sedimentation coefficients at the bottom of the centrifuge tube, indicating the presence of an aggregated form(s) of LPL; the amount of the monomeric form of LPL was increased, while that of the dimeric form was decreased. Thus, defect of LPL activity in post-heparin plasma of the patient with hyperchylomicronemia could result from reduced dimerization of LPL subunits.

Adolescent↗
PubMed1995

Isolation of p10 gene from Bombyx mori nuclear polyhedrosis virus and study of its promoter activity in recombinant baculovirus vector system.

A homologue of Autographa californica NPV (AcNPV) p10 gene was identified and cloned from Bombyx mori NPV (BmNPV). BmNPV p10 gene encodes truncated protein of 70 amino acid residues that lacks carboxyl terminus comparing with the p10 protein encoded by AcNPV. The putative TATA box sequence and the ATAAG motif which is the consensus sequence of baculovirus very late promoter were conserved. A transfer vector, pBNT1, which includes the p10 promoter region of BmNPV for foreign gene expression was constructed. By using pBNT1, a recombinant BmNPV, Bmp10-Luc, in which the p10 gene was replaced by the firefly luciferase gene, was obtained. We also obtained another recombinant virus, BmPH-Luc, in which the polyhedrin gene was replaced by the luciferase gene. The luciferase activity detected in BoMo-15AIIc insect cells infected with Bmp10-Luc was approximately 50% of that infected with BmPH-Luc, suggesting that although both the p10 and polyhedrin promoters of BrnNPV are effective in high-level expression of foreign genes, the p10 promoter is not so strong as the polyhedrin promoter.

Amino Acid Sequence↗
PubMed1995

Eicosapentaenoic acid modulates arachidonic acid metabolism in rat alveolar macrophages.

Eicosapentaenoic acid (EPA) is an unsaturated fatty acid contained in fish oils. In order to clarify the mechanism of its anti-inflammatory effects on the lung, we studied arachidonic acid (AA) metabolism by in vitro exposure of rat alveolar macrophages to EPA. EPA was found to inhibit the endogenous production of leukotriene B4 (LTB4) from AA. At a low concentration of EPA, generation of LTB5 was increased, while at a high concentration it was decreased. These results suggest that at a lower concentration EPA may be competitive with AA as a substrate, and that at a higher concentration it may directly inhibit AA metabolism via inhibition of 5-lipoxygenase or phospholipase A2.

Animals↗
PubMed1995

Pulmonary vascular resistance during exercise late after repair of large ventricular septal defects. Relation to age at the time of repair.

Postoperative pulmonary artery pressure and resistance were assessed during exercise in 32 patients late after repair of large ventricular septal defect with pulmonary hypertension. Nineteen patients had a preoperative pulmonary-to-systemic resistance ratio of between 0.15 and 0.50 (group 1) and 13 had a ratio between 0.50 and 0.96 (group 2). Age at the time of operation was 0.9 to 13.0 years (4.6 +/- 3.6) in group 1 and 0.8 to 15.8 years (4.3 +/- 4.2) in group 2. Age at the time of restudy was 9 to 21 years (14.5 +/- 3.0) in group 1 and 9 to 22 years (13.5 +/- 4.1) in group 2. Pulmonary artery pressure was measured in the supine position at rest and during exercise, as were the measurements underlying the calculations of pulmonary vascular resistance. Mean pulmonary artery pressure was 13 to 21 mm Hg (17 +/- 2) and 10 to 26 mm Hg (20 +/- 5) in groups 1 and 2, respectively, at rest, and this increased to 17 to 27 mm Hg (22 +/- 3) and 14 to 39 mm Hg (27 +/- 7) in groups 1 and 2, respectively, during exercise (p < 0.05). Pulmonary vascular resistance was 0.51 to 3.40 U.m2 (1.93 +/- 0.63) and 0.79 to 3.31 U.m2 (2.05 +/- 0.65) in groups 1 and 2 at rest. It was 0.58 to 2.24 U.m2 (1.36 +/- 0.57) and 0.81 to 3.85 U.m2 (2.18 +/- 0.97) in groups 1 and 2 during exercise (p < 0.01). Postoperative pulmonary vascular resistance during exercise correlated well with age at the time of repair in both groups (r = 0.65, p < 0.05 in group 1; r = 0.86, p < 0.001 in group 2). These data suggest that 85% of patients with a preoperative pulmonary-to-systemic resistance ratio of between 0.15 and 0.50 would have normal pulmonary vascular resistance during exercise when operated on at younger than 3.8 years old and 85% of those with a preoperative pulmonary-to-systemic resistance ratio of more than 0.50 would have normal pulmonary vascular resistance during exercise when operated on at younger than 1.1 years.

Adolescent↗
PubMed1995

Xestobergsterol C, a new pentacyclic steroid from the Okinawan marine sponge Ircinia Sp. and absolute stereochemistry of xestobergsterol A.

A new pentacyclic steroid, xestobergsterol C [1], possessing a cis C/D ring junction, has been isolated together with two known compounds, xestobergsterols A [2] and B [3], from the Okinawan marine sponge Ircinia sp., and the structure determined on the basis of spectral data. Reexamination of the nmr data of xestobergsterols A [2] and B [3] resulted in revision of the configuration at C-23 and of the conformation of ring D in 2 and 3. The absolute stereochemistry of xestobergsterol A [2] was established by the cd exciton chirality method.

Animals↗
PubMed1995

4,6-Dibromo-3-hydroxycarbazole (an analogue of caffeine-like Ca2+ releaser), a novel type of inhibitor of Ca(2+)-induced Ca2+ release in skeletal muscle sarcoplasmic reticulum.

1. 4,6-Dibromo-3-hydroxycarbazole (DBHC) was synthesized as an analogue of bromoeudistomin D (BED), a powerful Ca2+ releaser, and its pharmacological properties were examined. 2. In Ca2+ electrode experiments, DBHC (100 microM) markedly inhibited Ca2+ release from the heavy fraction of sarcoplasmic reticulum (HSR) induced by caffeine (1 mM) and BED (10 microM). 3. DBHC (0.1 to 100 microM) inhibited 45Ca2+ release induced by Ca2+ from HSR in a concentration-dependent manner. 4. DBHC (100 microM) abolished 45Ca2+ release induced by caffeine (1 mM) and BED (10 microM) in HSR. 5. Inhibitory effects of calcium-induced calcium release (CICR) blockers such as procaine, ruthenium red and Mg2+ on 45Ca2+ release were clearly observed at Ca2+ concentrations from pCa 7 to pCa 5.5, and were decreased at Ca2+ concentrations higher than pCa 5.5 or lower than pCa 7. However, DBHC decreased Ca2+ release induced by Ca2+ over the wide range of extravesicular Ca2+ concentrations. 6. [3H]-ryanodine binding to HSR was suppressed by ruthenium red, Mg2+ and procaine, but was not affected by DBHC up to 100 microM. 7. [3H]-ryanodine binding to HSR was enhanced by caffeine and BED. DBHC antagonized the enhancement in a concentration-dependent manner. 8. 9-[3H]-Methyl-7-bromo-eudistomin D, an 3H-labelled analogue of BED, specifically bound to HSR. Both DBHC and caffeine increased the KD value without affecting the Bmax value, indicating a competitive mode of inhibition. 9. These results suggest that DBHC binds to the caffeine binding site to block Ca2+ release from HSR. This drug is a novel type of inhibitor for the CICR channels in SR and may provide a useful tool for clarifying the Ca2+ releasing mechanisms in SR.

Animals↗
PubMed1995

Molecular epidemiology of a fast-food restaurant-associated outbreak of Escherichia coli O157:H7 in Washington State.

We studied the molecular epidemiology of the recent fast-food restaurant chain-associated Escherichia coli O157:H7 outbreak in Washington State. Genomic DNAs prepared from strains isolated from 433 patients were probed with radiolabelled Shiga-like toxin (SLT) I and SLT II genes and bacteriophage lambda DNA and were subsequently analyzed for their restriction fragment length polymorphism (RFLP) patterns. The SLT RFLP and lambda RFLP profiles of an E. coli O157:H7 strain isolated from the incriminated beef and prototype patient were compared with those of the patient isolates for determination of the concordance between patterns. Of the 377 patients with primary and secondary cases of infection epidemiologically linked to the outbreak, isolates from 367 (97.3%) of the patients displayed SLT RFLP and lambda RFLP profiles identical to those of the outbreak strains. Isolates from 10 of the 377 (2.6%) patients possessed SLT RFLP and lambda RFLP profiles different from those of the outbreak strains, and the patients from whom those isolates were obtained were subsequently characterized as having non-outbreak-related infections. The E. coli O157:H7 strains isolated from 31 of 44 (70.4%) patients who were epidemiologically excluded from the outbreak were linked to the outbreak by RFLP typing. Our results indicate that SLT RFLP and lambda RFLP analyses are stable and sensitive methods, and when they are used in conjunction with an epidemiological investigation they could result in an earlier recognition of outbreaks and their sources, hence prompting measures to prevent the continued transmission of E. coli O157:H7.

Animals↗
PubMed1995

The rabbit pulmonary cytochrome P450 arachidonic acid metabolic pathway: characterization and significance.

Cytochrome P450 metabolizes arachidonic acid to several unique and biologically active compounds in rabbit liver and kidney. Microsomal fractions prepared from rabbit lung homogenates metabolized arachidonic acid through cytochrome P450 pathways, yielding cis-epoxyeicosatrienoic acids (EETs) and their hydration products, vic-dihydroxyeicosatrienoic acids, mid-chain cis-trans conjugated dienols, and 19- and 20-hydroxyeicosatetraenoic acids. Inhibition studies using polyclonal antibodies prepared against purified CYP2B4 demonstrated 100% inhibition of arachidonic acid epoxide formation. Purified CYP2B4, reconstituted in the presence of NADPH-cytochrome P450 reductase and cytochrome b5, metabolized arachidonic acid, producing primarily EETs. EETs were detected in lung homogenate using gas chromatography/mass spectroscopy, providing evidence for the in vivo pulmonary cytochrome P450 epoxidation of arachidonic acid. Chiral analysis of these lung EETs demonstrated a preference for the 14(R),15(S)-, 11(S),12(R)-, and 8(S),9(R)-EET enantiomers. Both EETs and vic-dihydroxyeicosatrienoic acids were detected in bronchoalveolar lavage fluid. At micromolar concentrations, methylated 5,6-EET and 8,9-EET significantly relaxed histamine-contracted guinea pig hilar bronchi in vitro. In contrast, 20-hydroxyeicosatetraenoic acid caused contraction to near maximal tension. We conclude that CYP2B4, an abundant rabbit lung cytochrome P450 enzyme, is the primary constitutive pulmonary arachidonic acid epoxygenase and that these locally produced, biologically active eicosanoids may be involved in maintaining homeostasis within the lung.

Animals↗
PubMed1995

KL-6: a serum marker for interstitial pneumonia.

KL-6 is a mucinous high-molecular weight glycoprotein, expressed on type 2 pneumonocytes, which is reported to be elevated in the serum and bronchoalveolar lavage fluid of patients with interstital pneumonia. A total of 118 samples from 112 patients were measured, including 51 samples with three classes of interstital lung disease and 67 samples with 6 classes of noninterstital lung diseases, in order to clarify whether it was a useful marker of pneumonitis activity. The KL-6 level was significantly higher in patients with pneumonitis (1,187 +/- 689 U/mL; range, 224 to 2,656 U/mL) than in patients without pneumonitis (309 +/- 157 U/mL; range, 123 to 855 U/mL). The KL-6 level was also significantly higher in patients with clinically active pneumonitis (1,497 +/- 560) compared with inactive pneumonitis (441 +/- 276) (p < 0.001). The optimal criterion for separating patients with active pneumonitis from patients without pneumonitis was a KL-6 level of 500 to 700 U/mL according to receiver operating characteristic analysis. These results suggest that KL-6 is a useful marker for the clinical diagnosis of pneumonitis and for the evaluation of disease activity.

Antigens↗
PubMed1995

Evaluation of lymph nodes on computed tomography images in epidermoid lung cancer.

This study was undertaken to design the optimal criteria for practical guidelines for lymph node metastasis evaluation in epidermoid lung cancer. Resected lymph nodes (n = 214) were analyzed by preoperative computed tomography (CT) images and postoperative histopathological findings. Definite criteria were defined by efficiency, and possible criteria by receiver operating characteristic (ROC) analysis. Statistical values of highest efficiency in 214 lymph nodes revealed that the minor axis offered the best criteria (minor axis 13 mm; efficiency 93%). ROC curve using the minor axis which showed the highest values of sensitivity and specificity in the optimal criteria (minor axis 9.3 mm; sensitivity 76%, specificity 76%). The criteria of the paratracheal lymph nodes were smaller than those of tracheobronchial and subcarinal nodes. In conclusion, it is desirable to evaluate metastasis of lymph nodes by the minor axis, and criteria should be considered changeable to accommodate the anatomical location in epidermoid lung cancer.

Carcinoma, Squamous Cell↗
PubMed1995

Efficacy of stool examination for detection of Strongyloides infection.

To determine the efficacy of stool examination for detection of Strongyloides infection, 1,350 stool samples collected in Japan, Brazil, and Thailand were examined by four different methods (direct fecal smear, formalin-ether concentration. Harada-Mori filter paper culture, and agar plate culture). The newly developed agar plate culture method was highly effective; more than 96% of the positive cases were diagnosed by this method. The coprologic examination, however, was not sensitive enough for detecting chronic infections because more than 40% of the positive cases were overlooked even when persons with proven Strongyloides infection were re-examined several months later without intervening treatment. Therefore, it is essential to examine stool samples repeatedly to achieve a correct diagnosis, and even so, it is important to note that a negative result does not necessarily indicate the unequivocal absence of the infection.

Animals↗
PubMed1995

Hantavirus infection among Rattus norvegicus in Japan.

Seroepizootiological study of hantavirus infection among 393 urban rats (Rattus norvegicus) captured in six regions in Japan during the period from 1990 to 1994 was carried out by the indirect fluorescent antibody (IFA) test and Western blot (WB). Fifteen out of 393 (3.8%) rat sera were antibody-positive by IFA, i.e., Tokyo Port (12.8%, 6/47), Shimizu Port (5.7%, 2/35), Otaru Port (1.5%, 1/65) and Nagoya City (3.6%, 6/167). In two other regions, i.e., Kasai Seaside Park and Haneda Airport, rat sera were antibody-negative. One serum with a lower IFA titer, 1:64, from Otaru Port was confirmed to be antibody-positive by WB, while two sera from Shimizu Port (IFA titer, 1:32 and 1:64) were not. In Nagoya City, one out of four sera (IFA titer, 1:32) and one of two sera (IFA titer, 1:64) were also confirmed to be antibody-positive by WB. Continuous hantavirus infection among rats in Tokyo Port, Shimizu Port and Nagoya City and the existence of hantavirus among rats in Otaru Port were demonstrated.

Animals↗
PubMed1995

Elevation of tumour markers in serum and bronchoalveolar lavage fluid in pulmonary alveolar proteinosis.

It is unclear whether tumour markers are generally increased in the serum and bronchoalveolar lavage fluid (BALF) of patients with pulmonary alveolar proteinosis (PAP). To clarify this point, levels of tumour markers were measured in the serum and BALF of patients with PAP. Squamous cell carcinoma (SCC) antigen, carcinoembryonic antigen (CEA), and carbohydrate antigens sialyl Lewis (CA 19-9) and sialyl SSEA-1 (SLX) were assayed with radioimmunoassay kits. Cytokeratin 19 fragments (CYFRA) were measured by enzyme-linked immunosorbent assay. Values for the tumour markers in serum, except for SCC, exceeded cut-off values in some PAP patients. Levels of the markers were higher in BALF compared with those in serum, and were significantly elevated in PAP patients compared with control subjects. There was a significant inverse correlation between CA19-9 level in BALF and arterial oxygen tension (PaO2) in PAP patients. A gradual elevation of CA19-9 and SLX was observed in a patient who showed a decrease in PaO2 level during the study period. In the light of these findings, it is possible that levels of tumour markers in BALF, especially levels of CA19-9 and SLX, may reflect the severity of the disease in PAP patients.

Adult↗