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Biomedical subjects

T Tamura

Publications and source records attributed to T Tamura.

At least 1,063 records · Page 59Linked to original sources
PubMed1988

Long-term results of aortic valvuloplasty for aortic regurgitation associated with ventricular septal defect.

Long-term results in 64 patients who underwent aortic valvuloplasty for aortic regurgitation associated with ventricular septal defect are presented. The average age of the patients was 10.2 years and the average cardiothoracic ratio was 0.57 at the time of operation. The average degree of aortic regurgitation, as classified by Sellers, was 2.7. The type of ventricular septal defect was subpulmonic in 31 patients, perimembranous in 20, and was a total conal defect in five patients. Valvuloplasty was performed at one end of an aortic cusp in 23 patients, at two ends in 33, at three ends in six, and at four ends in two patients. There was one operative death (1.6%). The follow-up period was 447.7 patient-years, and there were no late deaths. The actuarial survival rate was 98.3% at 5, 10, and 15 years. Postoperative cardiac catheterization was performed in 40 patients. Valvuloplasty failure was defined as the presence of a cardiothoracic ratio greater than 0.6, a loud regurgitant murmur (Levine grade 3/6 or greater), moderate or severe aortic regurgitation (Sellers grade 3 or 4), or the necessity of reoperation. There were 17 patients whose valvuloplasty failed. The freedom from valvuloplasty failure was 74.2% at 5 and 10 years and 55.3% at 15 years. Eight patients underwent reoperation because of residual aortic regurgitation, and all survived. The freedom from reoperation was 90.1% at 5 years, 80.5% at 10 years, and 63.7% at 15 years. Multiple regression analysis revealed that older age, a greater cardiothoracic ratio, perimembranous ventricular septal defect, and multiple valvuloplasties were significant contributing factors for residual regurgitation after aortic valvuloplasty.

Actuarial Analysis↗
PubMed1988

Potential bile acid metabolites. 13. Improved routes to 3 beta, 6 beta- and 3 beta, 6 alpha-dihydroxy-5 beta-cholanoic acids.

New synthetic routes to three possible stereoisomers of hyodeoxycholic (3 alpha, 6 alpha-dihydroxy-5 beta-cholanic) acid are described. The principal reactions involved were inversion at C-3 of 3 alpha-hydroxy-6-oxo derivatives with diethyl azodicarboxylate-triphenylphosphine-formic acid and with N,N-dimethylformamide, without allomerization to the more stable 5 alpha form. On the basis of physical and chromatographic data, previously reported 3 beta, 6 alpha-dihydroxy-5 beta-cholanic acid and its methyl ester are shown to be C-3 epimeric mixtures. The 13C nuclear magnetic resonance spectra were of key importance in characterizing the stereoisomers and estimating their purity.

Chemical Phenomena↗
PubMed1988

Early and late results of reconstructive operation for congenital mitral regurgitation in pediatric age group.

Sixty-six children aged between 8 months and 15 years (average age 5.5 +/- 3.8 years) underwent mitral reconstructive operations for congenital mitral regurgitation between June 1969 and February 1987. The pathologic findings of the mitral valves were annular dilatation in 37 patients, cleft of the leaflet in eight, hypoplasia of the leaflet in 44, perforation of the leaflet in one, chordal elongation in 22, chordal absence in 16, and chordal shortening in seven. The methods of repair consisted of asymmetric annuloplasty (Kay-Reed method) in 61 patients, De Vega-type annuloplasty in one, plication of redundant leaflet in 15, and closure of cleft or perforation in nine. The single operative death (1.5%) was due to heart block. Follow-up data were available over 373.8 patient-years (average 5.7 years). The four late deaths (6.0%) were due to heart failure in two patients, pneumonia in one, and hepatitis in one. The actuarial survival rate was 93.1% +/- 3.1% at 7 years and 88.4% +/- 5.1% after 17 years. Valvuloplasty failed in 19 of the long-term survivors. One of these patients underwent mitral valve replacement 11 years after initial operation. The rate of freedom from reoperation was 86% +/- 10% after 17 years. The rate of freedom from valvuloplasty failure was 80% +/- 6.7% after 5 years, 67% +/- 7.2% after 10 years, and 44% +/- 11.9% after 15 years.

Adolescent↗
PubMed1987

Capillary gas chromatography of hydroxylated bile acid stereoisomers of the allo and normal series.

Relative retention times and methylene unit (MU) values were determined for 56 bile acids of the allo (5 alpha, A/B-trans) and normal (5 beta, A/B-cis) series, which differ from one another in the number, position and configuration of the hydroxyl groups at positions C-3, C-6, C-7 and/or C-12. The bile acids were derivatized to their methyl ester O-trimethylsilyl ethers (Me-TMS) and methyl ester O-dimethylethylsilyl ethers (Me-DMES), and chromatographed on fused-silica capillary columns, chemically bonded with non-selective OV-1 and selective PEG-20M liquid phases. Of the four possible combinations of derivatives and columns examined, Me-DMES on OV-1 and Me-TMS on PEG-20M were most suitable. The differences in the MU values between the 5 alpha- and 5 beta-series, and between the Me-DMES and Me-TMS ether derivatives, are also summarized. These retention data would be helpful in the identification of closely related bile acid stereoisomers or for estimation of their structures. photolysis.

Bile Acids and Salts↗
PubMed1987

Specific cellular proteins bind to critical promoter sequences of the adenovirus early EIIa promoter.

As an approach to the identification of essential factors required for specific expression of the adenovirus type 2 EIIaE early (EIIaE) promoter, an in vitro system was established. Under appropriate conditions, using crude extracts of non-infected HeLa cells, efficient and accurate EIIaE expression has been reproduced. As in vivo, this transcription was strongly dependent upon the integrity of two non-consensus TATA-like elements, T1 and T2, corresponding to the major (EIIaE1) and minor (EIIaE2) start sites, respectively, as well as upon intact upstream elements (A, between -40 and -50 and B, between -70 and -90) common to both overlapping promoters. The implication of specific DNA-binding proteins in the transcriptional effects mediated by these elements was demonstrated by DNAse I footprinting analyses. Both crude nuclear extracts and partially purified fractions confer specific protection against DNAse I digestion to the T1 and B promoter elements defined above, and to a far upstream region (element C, between -110 and -150), which has previously been identified as a weaker promoter element by in vivo transcriptional studies. Separation of the T1 recognition factor from those which bind to the upstream elements B and C by chromatographic fractionation of the extracts has also been achieved.

Adenovirus Early Proteins↗