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Biomedical subjects

K Miyahara

Publications and source records attributed to K Miyahara.

At least 163 records · Page 9Linked to original sources
PubMed1992

[A case of isolated tricuspid regurgitation associated with persistent left superior vena cava].

We presented a rare case of isolated tricuspid regurgitation (TR) associated with persistent left superior vena cava (PLSVC). A 69-year old female was admitted to our hospital because of arrhythmia and cardiomegaly. Pansystolic cardiac murmur of Levine 2/6 was heard in her Erb's area. Remarkable cardiomegaly was revealed as 78% of cardiothoracic ratio and electrocardiographic findings showed atrial fibrillation. Echocardiographically, obvious dilatation of coronary sinus, right atrium and right ventricle were recognized and left atrium was also dilated moderately. Although results of right cardiac catheterization showed almost normal pressure, remarkable TR of grade IV was registered by Doppler echocardiography. Additional diagnosis of PLSVC drained to dilated coronary sinus was made by venography from the left antecubital vein. But evidence of other cardiac shunt diseases and other abnormalities which might be a cause of TR was negligible. It is reported, in general, that PLSVC drained to coronary sinus occurs asymptomatically, and there is no accepted theory that PLSVC is able to be a cause of TR alone. So, we diagnosed our case as rare isolated TR associated with PLSVC, and because only two such cases are reported in Japanese, we reported it.

Aged↗
PubMed1992

[A case of acute extrinsic malfunction of prosthetic valve due to suture tag causing incomplete closure of the disc].

A 56-year-old woman who had suffered from both aortic and mitral valve stenosis and regurgitation was treated by replacement of valves with 23 mm and 27 mm Björk-Shiley valves respectively. After weaning from cardiopulmonary bypass, the arterial systolic pressure rose to 100 mmHg but the diastolic pressure fell to 40 to 50 mmHg. Studies including transesophageal echocardiogram and fluoroscopy during operation revealed the valves functioning normally. Because low diastolic pressure and low cardiac output continued during postoperative period, fluoroscopy was carried out again. It showed incomplete diastolic closure of the disc of the prosthetic aortic valve. The emergency operation was performed. At reoperation, it was found that one of the end of suture knots located between the valve ring and the disc prevented the occluder from seating completely and caused aortic regurgitation. The suture end was cut shorter and the prosthesis within the sewing ring was rotated so that the occluder was kept away from the suture end.

Aortic Valve↗
PubMed1991

An optimum dose of c-H-ras is a prerequisite for hormone-dependent conversion of a cell between cancerous and normal states in tissue culture.

We have established a few cell lines which can be reversibly converted from cancerous to normal and vice versa by the addition to, or removal from the culture medium of glucocorticoid hormone. These cell lines were derived from mouse NIH 3T3 cells and possessed the integrated gene pairs on chromosomes, which are composed of human mutated c-H-ras fused with mouse mammary tumour virus long terminal repeat and E. coli xanthine-guanine phosphoribosyltransferase gene with the SV40 promoter. We have characterised these cell lines in order to elucidate an essential requirement for the conversion of the state of a cell. It was found that the presence of at least two to three copies of the gene pair per diploid genome are essential. An approximate threshold level of c-H-ras 1.6 kb RNA required for reversible conversion was estimated.

Animals↗
PubMed1991

Molecular relationships between human parainfluenza virus type 2, and simian viruses 41 and 5: determination of nucleoprotein gene sequences of simian viruses 41 and 5.

The nucleotide sequences of cDNAs of the simian virus 5 (SV5) nucleoprotein (NP) gene, and the 3' end of the genome and NP gene of SV41 were determined. The open reading frames of the SV5 and SV41 NP genes encode polypeptides with Mrs of 56,582 and 60,575, respectively, values which are consistent with those estimated by SDS-PAGE. The NP of human parainfluenza virus type 2 (hPIV-2) was more closely related to that of SV41 (amino acid sequence identity 70.5%) than that of SV5 (57.0%); the amino acid sequence identity between the NPs of SV41 and SV5 was 63.3%. The sequence of the 3' end of the genome of SV41 showed a high level of similarity to that of hPIV-2, the terminal 18 nucleotides being identical. It is concluded from these findings that SV41 is related most closely to hPIV-2, even though SV5 had been thought to be an animal type of hPIV-2.

Amino Acid Sequence↗
PubMed1991

Remnant valve of inferior vena cava dislodged by Swan-Ganz catheter.

We experienced a rare case of a patient with acute myocardial infarction. It was rare in that a piece of tissue, probably a remnant valve of the inferior vena cava in the right atrium, was dislodged by the Swan-Ganz catheter during a right heart catheterization study in the chronic phase of the disease. As far as we know, no other such case has been reported. Such remnants are considered to be present in 2 to 3% of the general population. Therefore, it is necessary to determine the presence or absence of a remnant before cardiac catheterization and to modify the procedure, such as by changing the catheter's approach, when a remnant is present.

Aged↗
PubMed1991

[Congenital bicuspid aortic valve associated with aberrant coronary artery origin: a case report].

A 61-year-old man with congenital bicuspid aortic valve associated with aberrant coronary artery origin is presented. His aortic valve was severely stenotic with marked calcification. At the aortic valve replacement, it was found that the valve was markedly calcified and the bicuspid valve and both coronary ostia were very close to each other in a posteriorly positioned sinus of Valsalva. There have been a few reports concerning the combination of the bicuspid aortic valve and aberrant coronary artery origin, and it is well known that the bicuspid aortic valve more frequently accompanies short left main trunk or left coronary arterial dominance than a normal aortic valve. Some genetic mechanisms surrounding the coronary artery, aortic valve and aorta are suggested to occur with such anomalies.

Aortic Valve↗
PubMed1990

Cloning and expression of a cDNA for human cytochrome P-450aldo as related to primary aldosteronism.

A cDNA clone encoding human aldosterone synthase cytochrome P-450 (P-450aldo) has been isolated from a cDNA library derived from human adrenal tumor of a patient suffering from primary aldosteronism. The insert of the clone contains an open reading frame encoding a protein of 503 amino acid residues together with a 3 bp 5'-untranslated region and a 1424 bp 3'-untranslated region to which a poly(A) tract is attached. The nucleotide sequence of P-450aldo cDNA is 93% identical to that of P-450(11) beta cDNA. Catalytic functions of these two P-450s expressed in COS-7 cells are very similar in that both enzymes catalyze the formation of corticosterone and 18-hydroxy-11-deoxycorticosterone using 11-deoxycorticosterone as a substrate. However, they are distinctly different from each other in that P-450aldo preferentially catalyzes the conversion of 11-deoxycorticosterone to aldosterone via corticosterone and 18-hydroxycorticosterone while P-450(11)beta substantially fails to catalyze the reaction to form aldosterone. These results suggest that P-450aldo is a variant of P-450(11)beta, but this enzyme is a different gene product possibly playing a major role in the synthesis of aldosterone at least in a patient suffering from primary aldosteronism.

Amino Acid Sequence↗
PubMed1990

Cloning of cDNA and genomic DNA for human cytochrome P-45011 beta.

A full-length cDNA clone encoding steroid 11 beta-hydroxylase (P-45011 beta) has been isolated from a cDNA library derived from human adrenal tumor. The insert of the clone contains an open reading frame encoding a protein of 503 amino acid residues together with a 4 bp 5'-untranslated region and a 576 bp 3'-untranslated region to which a poly(A) tract is attached. The promoter region of the P-450(11) beta gene has also been isolated from a genomic library derived from human pre-B cells. It contains a TATA box, a putative cAMP-responsive element, several repeated sequences and two sequence elements similar to the consensus sequence for binding of AP-1. A transient expression assay in Y-1 adrenal tumor cells demonstrates that the promoter activity is remarkably enhanced by treatment of the cells with cAMP. In addition, analysis using deletion mutants containing various lengths of the 5'-flanking region of the gene suggests that several cis-acting elements participate in transcriptional regulation of human P-450(11) beta gene.

Adrenal Gland Neoplasms↗
PubMed1990

Scammonins I and II, the resin glycosides of radix scammoniae from Convolvulus scammonia.

The ether-soluble resin glycoside ('jalapin') fraction obtained from scammony roots, on alkaline hydrolysis, gave a glycosidic acid, scammonic acid A, together with isobutyric, 2S-methylbutyric and tiglic acids. In addition, two kinds of resin glycosides, named scammonin I and II, were isolated and characterized, respectively, as (11S)-hydroxyhexadecanoic acid, 11-[( O-6-deoxy-4-O-(2(E)-methyl-1-oxo-2- butenyl)-beta-D-glucopyranosyl-(1----4)-O-6-deoxy-2-O-(2-methyl-1-oxobut yl)- alpha-L-mannopyranosyl-(1----2)-O-beta-D-glucopyranosyl-(1----2)-6-deoxy -beta- D-glucopyranosyl]oxy)-, intramol. 1,3"'-ester and (11S)-hydroxyhexadecanoic acid, 11-[( O-beta-D-glucopyranosyl-(1----4)-O-6-deoxy-2-O-(2-methyl-1-oxobutyl)- alpha-L-mannopyranosyl-(1----2)-O-beta-D-glucopyranosyl-(1----2)-6-deoxy -beta-D - glucopyranosyl]oxy)-, intramol. 1,3"'-ester.

Carbohydrate Sequence↗
PubMed1990

Flow cytometric analysis of cellular DNA content in ovarian cancer.

A total of 169 paraffin-embedded tissue sections from 42 patients with epithelial ovarian cancer were subjected to analysis of cellular DNA content by flow cytometry. Twenty-three cases were found to be homogenously diploid, whereas 19 cases were aneuploid. A "mosaic" type containing both aneuploid and diploid cell populations was found in 11 of 19 aneuploid cases. Clinical features showed significant correlation with tumor ploidy of FIGO stage and bulky disease. In evaluation of the prognostic value of tumor ploidy, "mosaic" tumors were frequently observed in women who died of disease (DOD), whereas women with diploid tumors survived longer than those with "mosaic" tumors. The present results suggest that determination of DNA heterogeneity may be a valuable parameter in the prognosis of epithelial ovarian cancer.

DNA↗
PubMed1990

Preparations of 5-alkylmethylidene-3-carboxymethylrhodanine derivatives and their aldose reductase inhibitory activity.

Reactions of 3-carboxymethylrhodanine (1) with aldehydes (2a-u) afforded stereoselectively the 5-mono-alkylmethylidene-3-carboxymethylrhodanines (3a-u). The configuration of the 5-monoalkylmethylidene-3-carboxymethylrhodanine (3k) were examined by X-ray structure analysis and confirmed to be Z-configuration. The stereoselective reaction path was discussed. Several 5-dialkylmethylidene-3-carboxymethylrhodanines (15a-f) and alkylamino derivatives of 3-carboxymethylrhodanines (18a-o) were also prepared. These products were evaluated for aldose reductase-inhibitory potency and half of them exhibited valuable inhibitory potency.

Aldehyde Reductase↗
PubMed1990

Myocardial infarction induced by coronary venous thrombosis--an experimental study.

In a previous study, we proved experimentally that transmural infarction was produced in the area of the left anterior descending artery (LAD) by coronary sinus occlusion attributable to thrombus formation. In an attempt to produce infarction due to thrombus formation and to investigate the influence of thrombosis, the anterior interventricular vein (AIV) was occluded in this study. In each of 6 adult mongrel dogs, a balloon-tipped catheter was wedged in the AIV via the jugular vein. After the occlusion of blood flow by inflation of the balloon, thrombin (30-50 IU) was injected into the AIV to produce thrombi and the balloon was removed 60 min later. As a result, ischemic changes of ST and T in an ECG were clearly observed in all 6 dogs, and serum levels of myocardial enzymes supported the development of myocardial necrosis. Coronary arteriography performed 48 hours after the occlusion of the AIV showed normal findings in all 6 dogs, and residual thrombi in the AIV were observed in 5 dogs by coronary venography. In these 5 dogs, very local contraction band necrosis (CBN) was noted in the epicardium surrounding the AIV. These experimental findings indicate the following: 1) CBN can also be induced by coronary venous occlusion, 2) once the occlusive mechanism acts on the coronary venous system, the changes which are clinically similar to myocardial infarction can be induced regardless of its causes, 3) ischemic changes in myocardium can be localized in the epicardium irrespective of its causes. Therefore, these findings are considered to be important in the investigation of the clinical onset mechanism of myocardial infarction.

Animals↗
PubMed1990

Changes of lymphocyte subpopulations and natural killer cells in mice sensitized with Toxoplasma lysate antigen before and after Babesia infection.

When 8-week-old BALB/c mice were sensitized with two intramuscular injections of Toxoplasma lysate antigen (TLA) at 2 week interval, the numbers of sIg(+), Thy-1,2(+), Lyt-1,2(+) Lyt-2,2(+), and Asialo GM1(ASGM1)(+) cells in the spleen, liver and peripheral blood increased by 2 to 4 times over those found in unsensitized mice of the same age. When TLA-sensitized and unsensitized mice were infected with Babesia, 4 of 10 (40%) of the TLA-sensitized mice survived infection, while none of the unsensitized control mice lived longer than 14 days after Babesia infection. By contrast, sensitization of nude mice with TLA had no effect on survival, and mice did not live more than 12 days. The number of thymic Thy-1,2(+) cells decreased in TLA-sensitized and unsensitized BALB/c mice by almost 80% within 10 days after infection (AI). During the same time, the numbers of B cells, T cells, and NK cells increased in the spleen, liver and peripheral blood of both sensitized and unsensitized mice. Especially notable were increases in numbers of Lyt-2,2(+) cells in the spleen and blood and increases in numbers of NK cells in the spleen, liver and blood in both TLA-sensitized and unsensitized mice. When spleen cells from TLA-sensitized and unsensitized mice were cultured in the presence or absence of TLA for 6 days, assays for cytotoxicity using NK-insensitive P-815 target cells and NK-sensitive YAC-1 target cells demonstrated higher rates of cytotoxicity in cultures of TLA-sensitized spleen cells.

Animals↗
PubMed1990

The current therapeutic approaches to advanced ovarian cancer.

One hundred and fifty-nine cases of stage III or IV ovarian cancer treated at Kurume University and affiliated hospitals over the decade from 1978 to 1987 were analysed for their clinical outcome in relation to the therapeutic methods. The following results were obtained. 1) Two definite groups of patients were identified, one having a favourable prognosis with all patients surviving for at least three years after the initial treatment and the other, group of patients with poor prognosis who died within two years. There were significant differences in the clinical features of the two groups mentioned, i.e. in the performance status, the clinical stage, the type of operation carried out, the residual tumor, the application of second look laparotomy (SLO), the type of anti-cancer drug given and the use of maintenance chemotherapy. 2) The operations performed were primary surgery, including hysterectomy, bilateral adnexectomy and omentectomy or exploratory laparotomy. There was also a significant difference in the prognosis of those who received primary surgery compared to those given exploratory laparotomy. 3) A significant difference was also noted in the prognosis of cases with residual tumors less than 1 cm in diameter when compared to those which had larger residual tumors. 4) The application of SLO did not affect the prognosis. 5) Favourable results were obtained in the survival rate of cases who received cisplatin and also, 6) Favourable results were obtained in the survival rate of those patients who were given maintenance chemotherapy.

Adenocarcinoma↗
PubMed1989

Plasticity of DNA conformation around the Drosophila melanogaster alcohol dehydrogenase gene under torsional stress.

Genomic DNA of eukaryotes is thought to be organized into multiple topological domains whose conformation can be independently regulated by torsional stress. We have demonstrated the formation of altered DNA structures around the Drosophila melanogaster alcohol dehydrogenase (Adh) gene by sensitivity to endonucleases and by binding single-strand binding (SSB) protein. Several altered DNA structures were detected only on torsionally stressed DNA at specific sites. Some corresponded to the two initiation cap sites and the poly(A) addition sites and others were found in the 5'-flanking regions of both the adult and larval cap sites and in the 3'-flanking region of the Adh gene. In particular, the 5'-flanking regions both exhibited a plasticity of DNA conformation according to the strength of torsional stress and the concentration of Mg2+. SSB protein bound preferentially to the non-coding regions of the Adh gene only on torsionally stressed DNA and not on relaxed or linear DNA. The observed binding preference appeared to correspond to the thermodynamic stability of the base-pairs involved. These results suggest that DNA conformation is specifically organized around the Adh gene for gene function. The plasticity of DNA may play a role in the regulation of transcriptional activation.

Alcohol Dehydrogenase↗
PubMed1989

A study of drug efficacy in the treatment of ovarian cancer.

One hundred and nine cases of common epithelial ovarian cancer treated in our department during the past decade were entered into this study, which dealt with direct therapeutic effects and prognosis, comparing the groups administered cisplatin with those administered other anticancer drugs. 1) In 38 patients with measurable lesions, high response rates were achieved through the administration of anticancer drugs containing cisplatin in both the primary cancer and recurrent cancer groups. 2) Preventive chemotherapy was performed in patients in whom complete surgery was achieved at the initial operation. No significant difference in prognosis was observed through the administration of cisplatin and other anticancer drugs. 3) In patients in whom reduction surgery was carried out to the maximum possible degree at the initial operation, an improvement in prognosis was observed through the administration of cisplatin. These results imply that a cisplatin-based regimen should be aggressively used, except in cases that underwent complete debulking surgery.

Adenocarcinoma↗