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Biomedical subjects

Y Chiba

Publications and source records attributed to Y Chiba.

At least 145 records · Page 8Linked to original sources
PubMed1996

Small cell carcinoma of the uterine cervix with syndrome of inappropriate antidiuretic hormone secretion.

In a 59-year-old woman suffering from the syndrome of inappropriate antidiuretic hormone secretion, a small cell carcinoma of the uterine cervix was detected. The tumor was immunoreactive for antidiuretic hormone as well as for neuron specific enolase, chromogranin A, and Leu-7, but not vimentin. Electron microscopic examination of the tumor revealed neurosecretory granules. To our knowledge, this is only the second report of the syndrome of inappropriate antidiuretic hormone secretion with small cell carcinoma of the uterine cervix and the first one confirmed immunohistopathologically.

CD57 Antigens↗
PubMed1996

[Analysis of maternal and fetal risk in 594 pregnancies with heart disease].

The purpose of this study was to estimate the risk of heart diseases in pregnancy. A total of 594 patients with heart diseases treated at the National Cardiovascular Center between 1982 and 1993 were evaluated. The heart diseases were classified into eight categories: congenital heart disease with or without pulmonary hypertension (8 cases (1%) and 219 cases (37%), respectively), mitral valve prolapse (38 cases (6%)), valvular heart disease with or without valve replacement (9 cases (2%) and 54 cases (9%), respectively), arrhythmia (222 cases (37%)), cardiomyotitis (15 cases (3%)) and miscellaneous (29 cases (5%)). Maternal risk was estimated from the incidence of maternal mortality and artificial preterm delivery. Maternal death within two years after delivery was observed in 7 cases (1.2%): 4 cases with cardiomyotitis (3 DCM and 1 HCH), 2 cases with heart disease with pulmonary hypertension (1 PPH and 1 PDA), and a single case with valvular heart disease with aortic valve replacement. Artificial preterm delivery was carried out in 32 cases (5.4%), most frequently in cases with congenital heart disease with pulmonary hypertension (6/8, 75%) which follows cardiomyotitis (4/15, 27%) and cases with valvular heart disease with valve replacement (2/9, 22%). Fetal risk was measured by the incidence of fetal death, fetal growth retardation and congential heart disease of the fetus. IUFD because of maternal heart disease was observed in 4 cases: two cases with valvular heart disease with valve replacement, a single case with Marfan's syndrome and a single case with DCM. Fetal growth retardation was observed in 59 cases, most frequently in cases with congenital heart disease with pulmonary hypertension and cases with valvular heart disease with valve replacement (3/8 (38%) and 3/9 (33%), respectively). Neonatal congenital heart disease was found in 8 of 228 neonates (3.5%) whose mothers also had congenital heart disease. It is therefore suggested that intensive medical care be recommended in pregnancies complicated with congenital heart disease with pulmonary hypertension or with valvular heart disease with valve replacement, which increase both maternal and fetal risk, and in pregnancies complicated with cardiomyotitis which significantly increases the maternal risk.

Arrhythmias, Cardiac↗
PubMed1996

[Pneumocystis carinii pneumonia associated with high levels of serum KL-6].

In May 1995, a 52-year-old man complaining of fever and dyspnea was admitted to a hospital. Based on clinical and radiographic findings, hypersensitivity pneumonitis was suspected. Steroid pulse therapy was unsuccessful, and he was then transferred to our hospital. A chest X-ray film showed bilateral ground-glass shadows and a high-resolution CT scan showed cystic air spaces. The number of CD4-positive lymphocytes in peripheral blood was very low. A test for anti-human immunodeficiency virus antibody was positive and Pneumocystic carinii was found in bronchoalveolar lavage fluid. The acquired immunodeficiency syndrome and Pneumocystis carinii pneumonia were diagnosed. In this patient, the level of serum KL-6, a new marker of interstitial pneumonitis, was very high, and KL-6 was expressed on type II pneumocytes. The level of serum KL-6 may be useful as a marker of the activity of Pneumocystis carinii pneumonia.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Cloning and expression of the carboxypeptidase gene from Aspergillus saitoi and determination of the catalytic residues by site-directed mutagenesis.

Carboxypeptidase from Aspergillus saitoi removes acidic, neutral and basic amino acids as well as proline from the C-terminal position at pH 2-5. cpdS, a cDNA encoding A. saitoi carboxypeptidase, was cloned and expressed. Analysis of the 1816-nucleotide sequence revealed a single open reading frame coding for 523 amino acids. When A. saitoi carboxypeptidase cDNA was expressed in yeast cells, carboxypeptidase activity was detected in the cell extract and was immunostained with a 72 kDa protein with polyclonal anti-(A. saitoi carboxypeptidase) serum. The recombinant enzyme treated with glycopeptidase F migrated with an apparent molecular mass of 60 kDa on SDS/PAGE, which was the same as that of the de-N-glycosylated carboxypeptidase from A. saitoi. Site-directed mutagenesis of the cpdS indicated that Ser-153, Asp-357 and His-436 residues were essential for the enzymic catalysis. It can be concluded that A. saitoi carboxypeptidase has a catalytic triad comprising Asp-His-Ser and is a member of serine carboxypeptidase family (EC 3.4.16.1).

Amino Acid Sequence↗
PubMed1995

Alteration in Ca2+ availability involved in antigen-induced airway hyperresponsiveness in rats.

The origin of Ca2+ contributing to the enhancement of acetylcholine-induced bronchial smooth muscle constriction in airway hyperresponsiveness induced by antigen challenge was investigated. Under Ca(2+)-free (concomitant with 10(-6) M nicardipine) conditions, the contractile responses of bronchial rings to 1 mM acetylcholine were significantly greater in rings from rats with hyperresponsive airways (0.15 +/- 0.04 g) than those of rings from normal rats (0.02 +/- 0.004 g; P < 0.05). The cumulatively administered Ca2+ induced a markedly greater bronchoconstriction in rings from rats with hyperresponsive airways in Ca(2+)-free solution when muscles were pretreated with 1 mM acetylcholine (in the presence of 10(-6) M nicardipine) than in rings from normal rats, whereas no significant difference in Ca(2+)-induced bronchoconstriction was observed between the two groups when muscles were pretreated with 60 mM K+ (in the presence of 10(-6) M atropine). These findings suggest that enhancement of the availability of Ca2+ released from intracellular stores and/or influxed through receptor-operated Ca2+ channels in airway smooth muscles might be involved in the airway hyperresponsiveness to acetylcholine in rats.

Acetylcholine↗
PubMed1995

The successful repair of annuloaortic ectasia using Cabrol's operation in a 5-year-old child with Marfan's syndrome of the forme fruste type.

This report describes our experience of treating a 5-year-old boy with annuloaortic ectasia and a presumptive diagnosis of Marfan's syndrome. He had elongation of the distal aortic arch and dilatation of the abdominal aorta. Surgical repair of annuloaortic ectasia was successfully carried out using Cabrol's operation, following which no significant perioperative complications developed. To our knowledge, this is the first reported case of Cabrol's operation being successfully performed on a child aged 5 years or less.

Aortic Diseases↗
PubMed1995

Characteristics of muscarinic cholinoceptors in airways of antigen-induced airway hyperresponsive rats.

The antagonist and agonist binding sites of muscarinic receptors were investigated by using membrane preparations of airways from nonsensitized normal control, sensitized control and repeatedly antigen challenged rats. The in vitro bronchial responsiveness to ACh was markedly increased in repeatedly antigen challenged group but not in sensitized control group. No significant difference was observed in receptor density and antagonist affinity among these three groups. The affinity of ACh for high-affinity agonist binding sites of repeatedly antigen challenged group was much greater than those in the other groups; the affinity significantly reduced in the presence of GTP gamma S. We concluded that enhanced G protein level might be involved in inducing airway hyperresponsiveness in rats.

Acetylcholine↗
PubMed1995

Massive subcutaneous emphysema, pneumomediastinum, and spinal epidural emphysema as complications of violent coughing: a case report.

A 28-year-old man who manifested subcutaneous emphysema extending from the skull base and face to the chest, mediastinum and spinal epidural space following severe coughing caused by acute bronchitis is reported. Subcutaneous emphysema is a manifestation of non-surgical intrathoracic pathophysiology. In this patient percutaneous diagnostic peritoneal lavage resulted in the release of a large quantity of air and was negative for bleeding or contamination. No treatment other than antibiotics was prescribed. In this report, computer tomography study successfully demonstrated the areas of massive subcutaneous emphysema and the disappearance of the entrapped air, that might be absorbed into the tissues in the occupied sites within 7 days, except the air of epidural space, of a patient who manifested as a consequence of severe coughing caused by acute bronchitis.

Adult↗
PubMed1995

Inhibition of neutral endopeptidase increases airway responsiveness to ACh in nonsensitized normal rats.

The effects of sensory neuropeptides on the airway responsiveness to acetylcholine (ACh) were investigated in normal nonsensitized rats. The airway responsiveness to inhaled ACh was significantly increased after treatment with neurokinin A (NKA; 0.001%) or substance P (SP; 0.01%) aerosol in the presence of the neutral endopeptidase (NEP) inhibitor. NKA had a more potent effect than SP. Interestingly, the intravenous treatment with NEP inhibitor alone also induced airway hyperresponsiveness (AHR) to inhaled ACh. This AHR was significantly attenuated by pretreatment with a nonselective NK-receptor antagonist, [D-Pro2,D-Trp7,9]SP, systemic capsaicin, or bilateral cervical vagotomy, indicating that decreased NEP activity results in accumulation of endogenous sensory neuropeptide(s) and enhancement of vagal reflex to cause AHR. The airway responsiveness to ACh of isolated left main bronchus was also increased after treatment with 10(-6) M NKA, but not SP, together with 10(-6) M phosphoramidon. This in vitro AHR to ACh induced by phosphoramidon plus NKA was significantly attenuated by pretreatment with 10(-6) M tetrodotoxin. These findings suggest that overaccumulated sensory neuropeptides, especially NKA, may enhance the probability of transmitter release, probably via NK2 receptors, and that the enhanced transmitter release might be involved in AHR in rats.

Acetylcholine↗
PubMed1995

Direct in vivo observation of subendocardial arteriolar response during reactive hyperemia.

To study the vasodilatory capacity of subendocardial (ENDO) arterioles, we evaluated the reactive hyperemic responses of ENDO as well as subepicardial (EPI) arterioles in 40 dogs by our needle-probe intravital microscope. We also examined the individual and combined effects of an ATP-sensitive K+ channel blocker (glibenclamide, 200 micrograms/kg), an inhibitor of nitric oxide synthase (NG-monomethyl-L-arginine [L-NMMA], 2 mumol/min, 20 minutes), and an adenosine-receptor antagonist (8-phenyltheophylline [8PT], 0.75 mumol/min, 15 minutes). The percent increase in end-diastolic diameter of ENDO arterioles was larger (P < .01) than that of EPI arterioles during reactive hyperemia, especially for the arterioles larger than 120 microns (P < .01). The diastolic-to-systolic vascular pulsation amplitude at the peak flow was greater in ENDO than EPI arterioles (25% versus 6%, P < .05). Compared with control conditions, the presence of both glibenclamide and L-NMMA suppressed the vasodilation responses of ENDO arterioles (P < .01 for both) and EPI arterioles (P < .05 for both). The effect of L-NMMA was greater in ENDO arterioles (P < .01), but that of glibenclamide was not different between ENDO and EPI arterioles. 8PT influenced the hyperemic response, although statistical significance was found only in the flow response. The effect of combined infusion of L-NMMA and glibenclamide with or without 8PT was greater than that of individual infusions in both ENDO and EPI arterioles. Conclusions are as follows: (1) The vasodilatory response of ENDO arterioles was even larger than that of EPI arterioles. Thus, the smaller flow reserve of ENDO arterioles may be caused by other factors, including the greater effects of myocardial compression and nitric oxide on the ENDO arterioles. (2) The vascular responses of ENDO and EPI arterioles were modulated by both endothelium-independent and -dependent vasodilative factors, and the effect of each factor including adenosine was associated with the effects of others.

Adenosine↗
PubMed1995

Structure-activity relationship study of TXA2 receptor antagonists. 4-[2-(4-substituted phenylsulfonylamino)ethylthio]phenoxyacetic acids and related compounds.

We have recently reported that 4-[2-(4-substituted phenylsulfonylamino) ethylthio]phenoxyacetic acids and related compounds showed potent thromboxane A2 (TXA2) receptor antagonist activity. To understand how substituents affect the biological activity, the quantitative structure-activity relationship (QSAR) was analyzed by using the Hansch-Fujita method for 36 compounds, including newly synthesized compounds. The positive coefficient for pi R and FR in the results of the QSAR study suggested that a hydrophobic an sigma electron-withdrawing substituent R at the para-position of the phenylsulfonyl moiety is required to improve the activity. Further, a substituent R which is long and moderately wide, was suggested to be preferable for the activity. The positive coefficients for pi X,Y,W-COOH and sigma Q(1)-(6) may indicate that the introduction of a hydrophobic and electron-withdrawing group on the benzene ring of the phenoxy acetic acid moiety enhances the activity. The length of the W-COOH moiety may also be important. On the other hand, the effect of the presence of methylene (n = 1) was not clear.

Animals↗
PubMed1995

Substrate binding ability of chemically inactivated pectinase for the substrate pectic acid.

Pectinase (polygalacturonase) was purified from a commercial pectinase preparation from a mold. Substrate binding of pectinase was measured by centrifugal affinity chromatography using an immobilized substrate, pectic acid. Desorption of pectinase from the affinity matrix with the substrate pectin and pectic acid gave Kd values of 5.3 and 8.5 mg/ml, respectively. Chemical modification of pectinase by 1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimide (EDC) and diethyl pyrocarbonate (DEP) caused a loss of most of the enzyme activity, but the substrate binding ability was not impaired. Thus, the pectinase preparation was digested with lysyl endopeptidase and the resulting peptides were treated with pectic acid-affinity gel. Three peptide fragments, which were recovered from the affinity column and sequenced, were identical to sequences in the second pectinase gene from Aspergillus niger. The first peptide contained 17 amino acids, Asp101-Ser117, and the second and third peptides corresponded to 18 amino acids of Asn152-Asp169. These results indicate that the inactivated pectinase retained substrate binding ability and would function as an acidic polysaccharide recognizing protein.

Amino Acid Sequence↗
PubMed1995

Comparison of o-phthalaldehyde modification of alpha-amylases from porcine pancreas and Bacillus subtilis with Taka-amylase A.

A fluorescent reagent, o-phthalaldehyde (OPA), competitively inhibited porcine pancreatic alpha-amylase (PPA) with Ki values of 0.7-0.9 mM, while alpha-amylase from Bacillus subtilis (BS) was uncompetitively inhibited, with Ki values of 5.8-7.6 mM. In both cases, OPA gave a time-dependent irreversible inactivation, where the amylase activity was lost faster than the maltosidase activity. Zymograms of the course of OPA modification showed that PPA was converted into at least six, faster moving components and BS gave two components. The OPA modification was retarded by the addition of the substrate analog, cyclodextrins, and the OPA modified enzymes decreased in affinity for the substrate soluble starch. Stoichiometric measurement showed that both PPA and BS was inactivated by the incorporation of 1 mol of OPA per mol of enzyme. The role of OPA modification of alpha-amylases was discussed in relation to the regulation of catalytic activity of enzymes.

Animals↗
PubMed1995

Ritsu: a rhythm mutant from a natural population of Drosophila melanogaster.

We found a new clock mutation, ritsu (rit), in an inbred strain separated from a natural population of Drosophila melanogaster in Yamaguchi, Japan. This mutation lengthens the free-running period of the wild-type locomotor activity rhythm from ca. 24 hr to ca. 27 hr by lengthening both active and rest phases equally. To determine the loci involved, we established eight lines of chromosomal substituted flies between the inbred strain and Canton-S, and found that a major gene is located on the second chromosome. Furthermore, the result of recombination analysis suggested that the locus might be near or to the left of cl (2-18.8).

Animals↗
PubMed1995

[A case of simultaneous treatment with mitral valve replacement and aorto-coronary bypass grafting of hypertrophic obstructive cardiomyopathy and coronary artery disease].

A case of surgical treatment of coexistent hypertrophic obstructive cardiomyopathy (HOCM) and coronary artery disease (CAD) in a 65-year-old male patient is reported. He had been diagnosed as HOCM and treated conservatively with beta-blocker and Ca-antagonist, but his complaints of chest oppression and palpitation had increased. Echocardiography revealed a systolic anterior motion of the mitral valve and mitral regurgitation. Cardiac catheterization showed a severe mitral regurgitation and peak systolic pressure gradient of 35 mmHg between the left ventricular and systemic artery. In addition, selective coronary angiography demonstrated a 99% stenosis in segment 7. He underwent aortocoronary bypass grafting and concomitant mitral valve replacement, and marked symptomatic and hemodynamic benefit could be achieved. This case shows the coexistence of HOCM and CAD in the same patient and suggest not only HOCM but also CAD should be routinely examined in the patient with angina, particularly when operative management is contempted. This case further suggests that simultaneous treatment of both diseases is more beneficial than single treatment of CAD or HOCM.

Aged↗