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Biomedical subjects

T Mukai

Publications and source records attributed to T Mukai.

At least 325 records · Page 18Linked to original sources
PubMed1984

Nucleotide sequence of the gene for Escherichia coli ribosomal protein S15 (rpsO).

The nucleotide sequence of the ribosomal protein gene rpsO (S15) and its flanking region were determined. The amino acid sequence of S15 protein deduced from the nucleotide sequence is in good agreement with the published amino acid sequence with one exception. The nucleotide sequence shows two probable promoter sites about 100 nucleotides upstream from the initiation codon (AUG) of rpsO. Inspection of the sequence also revealed structural homology between the distal part of rpsO and the reported S15 binding region in 16S rRNA.

Bacterial Proteins↗
PubMed1984

Stress thallium-201 transaxial emission computed tomography: quantitative versus qualitative analysis for evaluation of coronary artery disease.

Stress thallium-201 myocardial distribution was quantitatively evaluated by emission transaxial tomography in 104 patients who underwent coronary arteriography. The initial uptake and percent washout of thallium were assessed by the circumferential profile curves of the three short-axis sections and one middle right anterior oblique long-axis section. This quantitative tomographic analysis showed abnormal distribution in all but two patients (98%) with coronary artery disease, whereas qualitative analysis showed abnormality in 76 of the patients (93%). Quantitative analysis showed better sensitivity (91%) for detecting involved coronary vessels than qualitative analysis (80%, p less than 0.01), especially in three vessel disease (82 versus 67%, p less than 0.05). For localization of individual vessel involvement, quantitative analysis showed high sensitivity (right coronary artery: 96%, left anterior descending artery: 90% and left circumflex artery: 88%) as compared with qualitative analysis (88, 83 and 63%, respectively, p less than 0.05), while similar specificity was observed (92% for quantitative and 93% for qualitative analyses). Furthermore, in the study of patients without infarction, myocardial segments supplied by coronary vessels with moderate stenosis (51 to 75%) revealed abnormality more often with quantitative (81%) than with qualitative (56%) analysis. Thus, quantitative analysis of stress thallium emission tomography provides improved sensitivity for the detection of diseased coronary vessels in patients with three vessel disease and those with moderate stenosis. It is a valuable technique for the evaluation of coronary artery disease.

Cardiac Catheterization↗
PubMed1984

Spontaneous mutations modifying the activity of alcohol dehydrogenase (ADH) in Drosophila melanogaster.

In a marked-inversion balanced lethal system of the second chromosome of Drosophila melanogaster, mutations were accumulated under minimum pressure of natural selection in 1000 individual lines that originated essentially from two individuals. After about 300 generations, the specific activities of alcohol dehydrogenase of 69 randomly selected individual lines were measured with replications using four replicated vials (on 2 days--two replications per day) by observing the reduction of NAD+ to NADH at 340 nm. Total soluble protein as the basis of standardization of enzyme activity was measured by the Lowry method for each vial. A control experiment was made immediately after the establishment of 20 individual lines from a single genotype. A significant increase in genetic variance was observed among the mutation-accumulating lines but was not detected in the control experiment. The statistical analysis of the data on the basis of the one-band/one-gene hypothesis suggests that many mutations controlling the activity of alcohol dehydrogenase occurred in regions different from the alcohol dehydrogenase locus itself, mainly in the noncoding DNA. Furthermore, it is suggested that transposon-like elements are related to the induction of these changes in alcohol dehydrogenase specific activities. Additional experimental evidence supporting this conclusion is also given.

Alcohol Oxidoreductases↗
PubMed1983

Rat aldolase isozyme gene.

Rat aldolase B mRNA was partially purified from liver polysomes by an immunochemical technique followed by oligo(dT)-cellulose column chromatography. Double-stranded cDNA, synthesized from this mRNA, was inserted into the PstI site of plasmid pBR322 employing the oligo(dC)-oligo(dG) tailing method. Clones containing aldolase B cDNA inserts were selected by colony hybridization using 32P-labeled purified mRNA as a specific probe. Several recombinant plasmids containing 600 to 1000 base pair inserts were isolated. Hybrid selection-translation experiments showed that they hybridize specifically with aldolase B mRNA. By overlapping restriction maps of several individual cDNA inserts, it was found that they spanned 1200 base pairs, which represented about 70% of the aldolase B mRNA sequence. The nucleotide sequence of the cDNA was then determined and the sequence of 180 amino acids from the COOH terminus and the entire 3' untranslatable nucleotide sequence were clarified. Although the complete amino acid sequence of rat aldolase B has not yet been reported, it was found that several amino acids neighboring the COOH-terminal tyrosine obtained by carboxypeptidase digestion completely coincided with those determined from the cDNA sequence; i.e. -Ser-Leu-Phe-Thr-Ala-Ser-Tyr-Thr-Tyr. Furthermore, a putative active site peptide appeared and is extensively homologous to those of rabbit aldolases A and B.

Amino Acid Sequence↗
PubMed1983

Reexamination of diversifying selection of polymorphic allozyme genes by using population cages in Drosophila melanogaster.

Several investigators have reported increased heterozygosity for allozyme markers in laboratory experiments simulating a variable environment and have concluded that there is diversifying selection for allozyme variants. We found no change in heterozygosity in 28 large population cages where temperature, food, and light were each set at three levels, two constant and one variable, in a factorial design. Specifically, there was no change in heterozygosity when 0, 1, 2, or 3 factors were variable. The discrepancy between our negative results and earlier positive ones is that our experiments were started from a large caged population of flies which had been maintained for 6 years-long enough to be very near to linkage equilibrium. We suggest that the earlier results may have been the result of linkage between neutral, or nearly neutral, allozyme markers and selected loci or in some cases, inversions.

Journal Article↗
PubMed1983

Superimposition of Krypton-81m single photon emission CT and X-ray CT images for cerebral blood flow evaluation.

Selective arteriographic infusion of krypton-81m was used to obtain cerebral single photon emission computed tomograms. These were then superimposed on X-ray computed tomograms to assess topographically the perfusion of the entire brain. This method enhances the detecting capability for abnormal perfusion areas and has been used in 21 patients with various brain diseases.

Carotid Artery Thrombosis↗
PubMed1983

Studies on the structure of a novel peptide antibiotic, K-582.

A novel peptide antibiotic, K-582, which exhibited significant growth inhibition of Candida, viruses and ascites tumor in mice, was found in the culture medium of a strain of Metarhizium anisopliae by Kondo et al. (J. Antibiotics 33, 535-542 (1980) ]. K-582 consisted of two components, designated K-582 A and K-582 B. Threonine, tyrosine, ornithine, and an unusual amino acid were common in both peptides, but lysine was an extra component of K-582 A. The unusual amino acid was identified to be threo-gamma-hydroxy-L-arginine (OHArg) by means of mass, nuclear magnetic resonance and infrared spectrometries of the derivatives and the related compounds. The threonine and the arginine were assigned to be L-configuration, and the ornithine and the tyrosine to be D-configuration in both K-582 A and K-582 B, and the lysine to be L-configuration by comparison of their optical rotatory dispersion spectra with those of standard amino acids. The elucidation of primary structure revealed that they were closely related heptapeptides with the following sequence: K-582 A:H-Arg-OHArg-Orn-Thr-Orn-Lys-Tyr-OH; K-582 B:H-Arg-OHArg-Orn-Thr-Orn-OHArg-Tyr-OH, and had the identical sequence in terms of the configuration of their constituents, namely L-L-D-L-D-L-D.

Amino Acid Sequence↗
PubMed1983

Multiaxial tomography of heart chambers by gated blood-pool emission computed tomography using a rotating gamma camera.

Fifteen patients and three volunteers underwent radionuclide blood-pool cardiac studies with electrocardiographic gating. Following conventional planar-gated imaging (anterior and left anterior oblique projections), emission computed tomography (ECT), using a rotating gamma camera, was performed. A series of transaxial tomograms of the cardiac chambers was obtained. The left ventricular short-axis plane, long-axis plane, and four-chamber-view plane were then reorganized; each chamber was visualized separately. Compared to gated planar imaging, this technique showed regional asynergy more clearly in patients with myocardial infarction and demonstrated dilatation of the atria and ventricles more accurately in patients with an atrial septal defect and valvular heart diseases. In addition, when a section of the heart is obtained at any angle with gated blood-pool ECT, three-dimensional assessment of cardiac chambers in motion is more precise; mutual superimposition becomes unnecessary.

Adult↗
PubMed1983

Pulmonary blood flow distribution measured by radionuclide-computed tomography.

Distributions of pulmonary blood flow per unit lung volume were measured with subjects in the prone, supine, and sitting positions by means of radionuclide-computed tomography of intravenously administered 99mTc-labeled macroaggregates of human serum albumin. The blood flow was greater in the direction of gravity in all 31 subjects except one with severe mitral valve stenosis. With the subject in a sitting position, four different types of distribution were distinguished. One type had a three-zonal blood flow distribution as previously reported by West and co-workers (J. Appl. Physiol. 19: 713-724, 1964). Pulmonary arterial pressure and venous pressure estimated from this model showed reasonable agreement with pulmonary arterial pressure and capillary wedge pressure measured by Swan-Ganz catheter in 17 supine patients and in 2 sitting patients. The method makes possible noninvasive assessment of pulmonary vascular pressures.

Adult↗
PubMed1983

Comparison of effects of smooth muscle relaxing drugs in intestinal smooth muscle of guinea pig.

Effects of smooth muscle relaxants on histamine-, Ba2+- and Ca2+-induced contractions, or on electrical activities were examined in the longitudinal smooth muscle of guinea-pig ileum or taenia coli, respectively. Papaverine, D-600 and diltiazem effectively inhibited the Ca2+ responses and the tonic components of the histamine and Ba2+ responses. Especially, D-600 and diltiazem depressed the Ca2+ responses in much lower concentrations than papaverine and theophylline. In contrast, benactyzine and etomidoline were not specific antagonists against the Ca2+ responses, and they were effective inhibitory agents on the phasic responses to histamine and Ba2+. Nitroprusside failed to reduce the three types of contractions effectively. These results suggest that these seven relaxants can be divided into four types. Influence of those relaxants on spontaneously- and Ba2+-evoked electrical activities are compatible with the above differentiation. The four types of relaxants used in this study seem to exert their actions on smooth muscle in different way. Nitroprusside, however, is not a potent relaxant against contractions of the intestinal smooth muscles.

Animals↗
PubMed1983

[A case of alpha-fetoprotein producing embryonal carcinoma of the stomach].

A 67-year-old man with complaints of general malaise and epigastralgia was admitted to our hospital for further examination. Upper GI series and endoscopy showed advanced cancer, Borrmann type II; biopsy specimens revealed pathological pictures of malignancy. The serum alpha-fetoprotein values were remarkably high (473,000 ng/dl); the liver scintigram revealed a space-occupying lesion in the right lobe and the abdominal CT-scan showed ascites and lymphadenopathy of the abdominal para-aortic region. Therefore, double cancer of the stomach and the liver was suspected. The patient died in a state of hepatic coma with a rapid increase of jaundice, ascites and right pleural effusion at 3 weeks after admission despite the anti-cancer treatment. Autopsy revealed embryonal carcinoma with yolk sac tumor elements of stomach origin, extensive metastasis to the liver, lung, peritoneum, and portal vein. The peroxidase anti-peroxidase technique revealed that primary and secondary tumor cells produced alpha-fetoprotein.

Aged↗