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Biomedical subjects

M Ohnishi

Publications and source records attributed to M Ohnishi.

At least 73 records · Page 4Linked to original sources
PubMed2000

Spironolactone inhibits the transcardiac extraction of aldosterone in patients with congestive heart failure.

OBJECTIVES: The study evaluated the transcardiac extraction or spillover of aldosterone (ALDO) in normal subjects and in patients with congestive heart failure (CHF). BACKGROUND: Aldosterone promotes collagen synthesis and structural remodeling of target organs such as the heart. Spironolactone, an ALDO receptor antagonist, has recently been reported to reduce the mortality of patients with CHF; however, the effects of spironolactone on the transcardiac gradient of ALDO have not been clarified. METHODS: We measured plasma ALDO in the aortic root (AO) and coronary sinus (CS) in normal subjects and 113 consecutive CHF patients and also measured plasma procollagen type III aminoterminal peptide (PIIINP) in CS, a biochemical marker of myocardial fibrosis. RESULTS: Plasma ALDO was significantly lower in the CS than in the AO in normal subjects (n = 15; 61.2 +/- 9.3 vs. 83.1 +/- 11.8 pg/ml, p < 0.0001). In 96 CHF patients who did not receive spironolactone, plasma ALDO was significantly lower in the CS than in the AO (59.3 +/- 3.9 vs. 73.8 +/- 4.9 pg/ml, p < 0.0001). In contrast to the difference in these 96 patients, there was no significant difference in ALDO between the AO and CS in 17 patients who received spironolactone (127.4 +/- 20 vs. 124.0 +/- 19 pg/ml, p = 0.50). Stepwise multivariate analyses showed that spironolactone therapy had an independent and significant negative relationship with the transcardiac gradient of plasma ALDO in patients with CHF. In addition, significant positive correlations were seen between the transcardiac gradient of plasma ALDO and PIIINP (r = 0.565, p < 0.0001) and the left ventricular end-diastolic volume index (r = 0.484, p < 0.0001). CONCLUSIONS: These results indicate that plasma ALDO is extracted through the heart in normal subjects and in CHF patients who do not receive spironolactone and that spironolactone inhibits the transcardiac extraction of ALDO in CHF patients, suggesting that spironolactone blocks the effects of ALDO on the failing heart in patients with CHF.

Adolescent↗
PubMed2000

Sex dependence of the components and structure of urinary calculi induced by biphenyl administration in rats.

To obtain definitive information about the mechanisms of urinary calculus formation and the structural characteristics of the calculi induced by biphenyl administration in rats, with a focus on the sex dependency, the constituents of the urinary calculi were analyzed by HPLC, inductively coupled plasma spectroscopy (ICP), micro Fourier transform infrared spectroscopy (mFT-IR), and ion chromatography (IC), and structural analyses were carried out by microscopy, mFT-IR, and the electron probe microanalyzer (EPMA) method. We attempted to account for the appreciably higher incidence of calculi in males than in females. mFT-IR analysis revealed that the biphenyl-induced urinary calculi in male rats are composed mainly of potassium 4-hydroxybiphenyl-o-sulfate (4-HBPOSK), whereas the calculi in female rats are composed mainly of 4-hydroxybiphenyl (4-HBP) and KHSO(4) produced by the hydrolysis of 4-HBPOSK. Observations of photomicrographs and the results of mFT-IR analysis indicated that the calculi in males have a multilayer structure consisting of alternating layers of 4-HBPOSK and calcium phosphate, whereas the calculi in females have no multilayer structure, but open holes in which needle-shaped crystals are present in some places. In view of the results of these analyses, including the EPMA analysis, it appears that calculus formation in males may involve a series of successive and irreversible reactions, whereas calculus formation in females may result from a series of reversible reactions, including the hydrolysis of 4-HBPOSK. It was inferred that the series of irreversible reactions involved in calculus formation in males is relatively more stable than that in the case of females, and thus, a sex difference in the reaction features may be responsible for the observed difference in the incidence of calculus formation.

Animals↗
PubMed2000

Role of P-selectin in the migration of neutrophils to chemoattractant-induced cutaneous inflammation in mice.

The role of P selectin in the accumulation of neutrophils at acute dermal inflammatory sites induced by chemoattractants, LTB4 and IL-8 was investigated in the mouse. A mouse P-selectin-human IgG chimera bound to mouse neutrophils in vitro in a calcium-dependent manner, as detected by flow cytometry. A rat monoclonal antibody (mAb) against mouse P-selectin, RB40.34 abolished P-selectin-IgG chimera binding to mouse neutrophils, but a control antibody did not. Intradermal injection of LTB4 at a dose of 100 ng/site caused neutrophil accumulation to increase by 3-4 fold, as detected by measuring myeloperoxidase activity. Neutrophil extravasation to perivascular tissue was detected by histochemical observation. The intravenous injection of RB40.34 or the specific LTB4 antagonist, SM-15178, at doses at 5 mg/kg attenuated the accumulation of neutrophils by 55.6% and 70.3%, respectively, but a control antibody showed no effect. Similarly, intradermal administration of IL-8 at a dose of 5 microg/site induced significant neutrophil migration into the interstitial tissue of the skin, as followed by measuring myeloperoxidase activity and histopathologic analysis. The intravenous injection of RB40.34 at a dose of 5 mg/kg reduced the neutrophil accumulation by 59.2% in contrast, a control antibody showed no effect. To our knowledge, this is the first direct demonstration that P-selectin plays a substantial role in LTB4- and IL-8-induced neutrophil accumulation in mouse skin.

Animals↗
PubMed2000

The R-type pyocin of Pseudomonas aeruginosa is related to P2 phage, and the F-type is related to lambda phage.

Pseudomonas aeruginosa produces three types of bacteriocins: R-, F- and S-type pyocins. The S-type pyocin is a colicin-like protein, whereas the R-type pyocin resembles a contractile but non-flexible tail structure of bacteriophage, and the F-type a flexible but non-contractile one. As genetically related phages exist for each type, these pyocins have been thought to be variations of defective phage. In the present study, the nucleotide sequence of R2 pyocin genes, along with those for F2 pyocin, which are located downstream of the R2 gene cluster on the chromosome of P. aeruginosa PAO1, was analysed in order to elucidate the relationship between the pyocins and bacteriophages. The results clearly demonstrated that the R-type pyocin is derived from a common ancestral origin with P2 phage and the F-type from lambda phage. This notion was supported by identification of a lysis gene cassette similar to those for bacteriophages. The gene organization of the R2 and F2 pyocin gene cluster, however, suggested that both pyocins are not simple defective phages, but are phage tails that have been evolutionarily specialized as bacteriocins. A systematic polymerase chain reaction (PCR) analysis of P. aeruginosa strains that produce various subtypes of R and F pyocins revealed that the genes for every subtype are located between trpE and trpG in the same or very similar gene organization as for R2 and F2 pyocins, but with alterations in genes that determine the receptor specificity.

Amino Acid Sequence↗
PubMed2000

Phage conversion of exfoliative toxin A production in Staphylococcus aureus.

The staphylococcal exfoliative toxins (ETs) are extracellular proteins that cause splitting of human skin at the epidermal layer during infection in infants. Two antigenically distinct toxins possessing identical activity have been isolated from Staphylococcus aureus, ETA and ETB. The gene for ETA (eta) is located on the chromosome, whereas that for ETB is located on a large plasmid. The observation that relatively few clinical isolates produce ETA suggests that the eta gene is acquired by horizontal gene transfer. In this study, we isolated a temperate phage (phiETA) that encodes ETA and determined the complete nucleotide sequence of the phiETA genome. phiETA has a head with a hexagonal outline and a non-contractile and flexible tail. The genome of phiETA is a circularly permuted linear double-stranded DNA, and the genome size is 43 081 bp. Sixty-six open reading frames (ORFs) were identified on the phiETA genome, including eta, which was found to be located very close to a putative attachment site (attP). phiETA converted ETA non-producing strains into ETA producers. Southern blot analysis of chromosomal DNA from clinical isolates suggested that phiETA or related phages are responsible for the acquisition of eta genes in S. aureus.

Animals↗
PubMed2000

Significant roles of endothelin-A- and -B-receptors in renal function in congestive heart failure.

Endothelin-1 (ET-1) not only causes potent vasoconstriction but also leads to fluid retention, both actions mediated by ET(A)- and/or ET(B)-receptors. Selective ET(A)- and combined ET(A)/ET(B)-receptor antagonists improve hemodynamics in heart failure; however, it is also important to evaluate the effects of these antagonists on urine output in heart failure. We administered an acute dose of either the selective ET(A)-receptor antagonist FR139317 (FR, n=5, 1 and 3 mg/kg) or the mixed ET(A)/ET(B)-receptor antagonist TAK-044 (TAK, n = 5, 1 and 3 mg/kg) to dogs with heart failure induced by rapid ventricular pacing. Renal hemodynamic and tubular functions were subsequently investigated. FR increased urinary excretion in association with increased renal plasma flow (RPF) and glomerular filtration rate (GFR) with no significant changes in the fractional reabsorption of water distally (FRWD). In contrast, despite increased GFR, TAK did not alter urine volume or RPF with significantly increased FRWD. The increase of GFR and RPF induced by FR was significantly larger than that of TAK. These findings indicate that ET(B)-receptor activation may result in diuresis by renal vasodilatation and reduction of water reabsorption in the distal tubules and collecting ducts. Acute ET(A)-receptor antagonism may therefore be more beneficial to diuresis than dual ET(A)/ET(B)-receptor inhibition in heart failure.

Animals↗
PubMed2000

Chronic effects of an orally active selective endothelin-B-receptor antagonist in experimental congestive heart failure.

Endothelin-B- (ETB) receptors located in vascular beds mainly mediate vasorelaxation, however, long-term treatment with a mixed ETA/ETB receptor antagonist has been shown to improve the survival rate of rats with heart failure in a similar way to ETA-receptor inhibitors. The inhibition of ETB-receptor-mediated action should therefore be beneficial in preventing the deterioration seen in heart failure, despite various adverse hemodynamic effects. We administered K-8794 (Kowa Co. Ltd, Japan, 2mg/kg/day, n = 6), an orally active selective ETB-receptor antagonist, to dogs with heart failure induced by rapid right ventricular pacing for 14 days, commencing 8 days after pacing. Control dogs were given a placebo (n = 6). Mean arterial pressure decreased and systemic vascular resistance increased in both groups at the end of the protocol. In the K-8794 group, however, those values were higher than in the control group. Cardiac output decreased in both groups, but there were no significant differences observed between the two groups. Plasma renin activity and aldosterone increased in both groups at the end of the protocol, however levels in the K-8794 group were significantly lower than those in the control group. In the K-8794 group, it was quite interesting to note that Na excretion and urine flow rate were higher than in the control group. Our findings thus suggest that, although ETB-receptor antagonism produces some hemodynamic disadvantages, it can successfully prevent body fluid retention through the suppression the activation the renin-angiotensin-aldosterone system in dogs with heart failure.

Administration, Oral↗
PubMed2000

Molecular analysis of the folC gene of Pseudomonas aeruginosa.

We have cloned the Pseudomonas aeruginosa folC gene coding for folylpolyglutamate synthetase-dihydrofolate synthetase, which was located between the trpF and purF loci, and determined the nucleotide sequence of the folC gene and its flanking region. The deduced amino acid sequence of P. aeruginosa FolC was highly homologous to that of Escherichia coli FolC. The cloned gene complemented E. coli folC mutations and was found to encode both folylpolyglutamate synthetase and dihydrofolate synthetase activities. The gene organization around the folC gene in P. aeruginosa was completely conserved with that in E. coli; the accD gene was located upstream of the folC gene, and dedD, cvpA and purF genes followed the folC gene in this order. The gene arrangement and the result of the promoter activity assay suggested that the P. aeruginosa accD and folC genes were co-transcribed.

Acetyl-CoA Carboxylase↗
PubMed2000

Triple marker screening for trisomy 21, trisomy 18 and open neural tube defects in singleton pregnancies of native Japanese pregnant women.

OBJECTIVE: To report the results of prenatal triple marker screening on a population of Japanese pregnant women. METHODS: From April 1994 through March 1999, a total of 32,925 native Japanese women with singleton pregnancies requested a triple marker-screening test. Multiples of the median values for 3 markers and individual risks for each patient were calculated following adjustment for the Japanese weight correction factor. The risk cut-off values used for Down syndrome (T21), open spina bifida (OSB) and trisomy 18 (T18) were 1: 295, 1: 290, and 1: 100, respectively. Follow-up information was collected postpartum and statistically analyzed. RESULTS: Detection rates (DR) of T21 for women less than 35 years, over 35 years and overall were 58, 94, and 83%, respectively. DR of T18 for women less than 35 years, over 35 years and overall were 75, 79, and 79%, respectively. DR of open neural tube defects (ONTD) was 100%. CONCLUSIONS: The first cumulative data of an intervention program and prospective follow-up studies in Japan have proven to be similar to other published reports. Individual risk values were calculated for each pregnancy for T21, T18 and ONTD. This screening program is more effective than age-dependent screening for detecting T21, T18 and ONTD pregnancies.

Adult↗
PubMed2000

Cerebrosides in grapevine leaves: distinct composition of sphingoid bases among the grapevine species having different tolerances to freezing temperature.

Cerebrosides from leaves of three grapevine species were analyzed in detail. The relative proportions of 8-E/Z isomers of 4-hydroxy-8-sphingenines [i.e. 8-E/Z t18:1(8E) and (8Z)] differed amongst the species in respect to freezing tolerance. This suggests that the occurrence of high levels of t18:1(8Z) in cerebrosides is correlated with freezing tolerance in these species.

Acclimatization↗
PubMed2000

[IL-1 and TNF-alpha-mediated regulation of IL-6, IL-8, and GM-CSF release from cultured nasal epithelial cells].

IL-6, IL-8 and GM-CSF regulate inflammatory cell infiltration and survival at sites of inflammation. IL-1, TNF-alpha, IL-6, IL-8 and GM-CSF have been reported to be released from cultured nasal epithelial cells (CNEC). Here, focusing on IL-1 and TNF-alpha as key cytokines, we examined whether these two cytokines could regulate the release of IL-6, IL-8 and GM-CSF from CNEC. CNEC were treated with antibodies to IL-1 alpha and TNF-alpha at various doses for a period of 48 hrs. The levels of IL-6, IL-8 and GM-CSF in the culture supernatants were then estimated by ELISA. Treatment of CNEC with antibodies to IL-1 alpha and TNF-alpha inhibited the release of IL-6, IL-8 and GM-CSF from them in a dose-dependent manner. The inhibition of IL-6 and GM-CSF release was significantly greater after treatment of the CNEC with the antibodies to IL-1 alpha. Furthermore CNEC expressed IL-1 receptors and TNF receptors. These results suggest that the epithelial cell-derived IL-1 alpha and TNF-alpha can regulate the release of other cytokines like IL-6, IL-8 and GM-CSF in an autocrine manner.

Adult↗
PubMed2000

[Anesthesia for MIDCAB (minimally invasive direct coronary bypass) in a patient with Tangier disease: a case report].

Tangier disease is a rare, autosomally-inherited disorder of lipoprotein metabolism characterized by absence or marked deficiency of normal high density lipoprotein (HDL) cholesterol in plasma resulting in the accumulation of cholesteryl esters in various organs. The patient was a 55-yr-old male diagnosed as Tangier disease 16 years before. He had angina on exercise and his coronary angiogram revealed triple vessel disease including left main trunk (LMT) lesion. Stenosis of the right coronary artery was treated by percutaneous transluminal coronary angioplasty (PTCA). He was scheduled for a MIDCAB for further PTCA to be performed to relieve the stenosis of LMT. Preoperative laboratory data and physical examination showed total cholesterol 36 mg.dl-1, HDL-cholesterol 2 mg.dl-1, apoprotein A-I not-detected, pancytopenia, hyperplastic orange tonsils, splenomegaly and hepatomegaly. Clonidine 0.225 mg was orally given as a preanesthetic medication. Anesthesia was induced with fentanyl and midazolam and maintained with propofol, sevoflurane and supplemental fentanyl. Nitroglycerin and diltiazem were infused continuously. ST segment was elevated transiently during the clamping of the left anterior descending branch. Hemodynamic parameters were stable during the operation. He was extubated 2 hours after the end of the operation. No significant changes were found in postoperative EKG, total cholesterol, HDL-cholesterol and triglyceride. Perioperative course was uneventful.

Anesthesia↗
PubMed2000

[A comparison between three methods to investigate falls among the elderly living in the community].

PURPOSE: Interview survey is the often selected method to investigate falls among the elderly. However, the reliability of data obtained by that method has not be confirmed. The aim of this study is to clarify the number of intervals of recollection that should be specified to ensure accurate data when we investigate falls by using interview surveys among the elderly. METHODS: We carried out a total health survey among the elderly in Shigenobu town, and reported about the frequency of falls and its relating factors. Sex, age, walking ability over a distance of 1 km and hospitalization experience for past 1 year were related to falls significantly. In this study, we set 3 groups matching for the above factors in addition to history of falls during the preceding a year, and for one year we asked about falls every month for the first group (116 participants), every 3 months for the second group (116 participants) respectively. The third group (118 participants) was asked once at the end of this study. These three groups totaled 350 persons who were participants of physical fitness measurements that we carried out in Shigenobu town. The existence of falls was investigated by mail, and the nonrespondents were questioned by direct telephone calls. RESULTS: For reasons such as death, moving out, hospitalization and answer denial, persons whose answer was not obtained were excluded from the analysis. Finally, 87.1% in the 1st group, and 89.7% in the 2nd group and 96.6% in the 3rd group were analyzed. Statistically significant difference for the above factors related to falls did not exist among the 3 groups. Annual incidence for falls tended to be more frequent in the 1st group that in the 3rd group (20.5% in the 1st group, 15.9% in the 2nd group and 6.4% in the 3rd group) in males. In females, such a difference was not observed. (26.3% in the 1st group, 18.3% in the 2nd group and 20.9% in the 3rd group). CONCLUSIONS: There were no significant differences for the factors related to falls in 3 groups, therefore, the groups had almost similar backgrounds. In men, the difference of annual reported incidence between the 1st group and the 3rd group may be due to differences in the method of recollection.

Accidental Falls↗
PubMed1999

Chromosome of the enterohemorrhagic Escherichia coli O157:H7; comparative analysis with K-12 MG1655 revealed the acquisition of a large amount of foreign DNAs.

A complete Xba I and Bln I cleavage map was constructed for the chromosome of an enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain isolated from an outbreak in Sakai City, Japan, in 1996. A comparative chromosome analysis with E. coli K-12 strain MG1655 was made. The EHEC chromosome was approximately 5600 kb in length, 1 Mb larger than that of MG1655. Despite the marked difference in chromosome length, the location and direction of seven rRNA operons of the EHEC strain were similar to those for MG1655. Overall organization of genes common in both strains is also highly conserved. Chromosome expansion was observed throughout the EHEC chromosome, albeit in an uneven manner. A large portion of the chromosome enlargement was observed in the region surrounding the replication terminus, particularly in a segment containing the terA locus. Sample sequencing of 3627 random shotgun clones suggested the presence of approximately 1550 kb strain-specific DNAs on the EHEC chromosome, most of which are likely to be of foreign origin.

Bacterial Toxins↗
PubMed1999

Observation of Multi-TeV Gamma Rays from the Crab Nebula using the Tibet Air Shower Array.

The Tibet experiment, operating at Yangbajing (4300 m above sea level), is the lowest energy air shower array, and the new high-density array constructed in 1996 is sensitive to gamma-ray air showers at energies as low as 3 TeV. With this new array, the Crab Nebula was observed in multi-TeV gamma-rays and a signal was detected at the 5.5 sigma level. We also obtained the energy spectrum of gamma-rays in the energy region above 3 TeV which partially overlaps those observed with imaging atmospheric Cerenkov telescopes. The Crab spectrum observed in this energy region can be represented by the power-law fit dJ&parl0;E&parr0;&solm0;dE=&parl0;4.61+/-0.90&parr0;x10-12&parl0;E&solm0;3 TeV&parr0;-2.62+/-0.17 cm-2 s-1 TeV-1. This is the first observation of gamma-ray signals from point sources with a conventional air shower array using scintillation detectors.

Journal Article↗
PubMed1999

Protein phosphatase 2C inactivates F-actin binding of human platelet moesin.

During activation of platelets by thrombin phosphorylation of Thr(558) in the C-terminal domain of the membrane-F-actin linking protein moesin increases transiently, and this correlates with protrusion of filopodial structures. Calyculin A enhances phosphorylation of moesin by inhibition of phosphatases. To measure this moesin-specific activity, a nonradioactive enzyme-linked immunosorbent assay method was developed with the synthetic peptide Cys-Lys(555)-Tyr-Lys-Thr(P)-Leu-Arg(560) coupled to bovine serum albumin as the substrate and moesin phosphorylation state-specific polyclonal antibodies for the detection and quantitation of dephosphorylation. Calyculin A-sensitive and -insensitive protein-threonine phosphatase activities were detected in platelet lysates and separated by DEAE-cellulose chromatography. The calyculin A-sensitive enzyme was identified as a type 1 protein phosphatase. The calyculin A-insensitive enzyme activity was purified to homogeneity by phenyl- Sepharose, protamine-, and phosphonic acid peptide-agarose chromatography and characterized biochemically and immunologically as a 53-kDa protein(s) and a type 2C protein phosphatase (PP2C). Phosphorylation of Thr(558) is necessary for F-actin binding of moesin in vitro. The purified enzyme, as well as bacterially made PP2Calpha and PP2Cbeta, efficiently dephosphorylate(s) highly purified platelet phospho-moesin. This reverses the activating effect of phosphorylation, and moesin no longer co-sediments with actin filaments. In vivo, regulation of these phosphatase activities are likely to influence dynamic interactions between the actin cytoskeleton and membrane constituents linked to moesin.

Actins↗