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Biomedical subjects

T Mukai

Publications and source records attributed to T Mukai.

At least 307 records · Page 17Linked to original sources
PubMed1985

Nucleotide sequence of a cDNA clone for human aldolase: a messenger RNA in the liver.

Nearly complete cDNA clones for human aldolase A mRNA were isolated from human liver cDNA library and the nucleotide sequence determined. Using the cDNA clone as a probe the length of human aldolase A mRNAs, isolated from the skeletal muscle, liver and placenta tissues, was measured by RNA blotting and estimated to be 1,600 nucleotides for skeletal muscle mRNA and 1,700 nucleotides for both the liver and placenta mRNAs, indicating that different species of mRNA coding for human aldolase A were expressed in the different tissues.

Amino Acid Sequence↗
PubMed1985

Human aldolase isozyme gene: the structure of multispecies aldolase B mRNAs.

A complete nucleotide sequence of human aldolase B mRNA was determined with a recombinant cDNA (pHABL120-3). The cDNA insert was composed of 1,652 bases excluding poly(A) tail and the sequence was consistent with the previous results reported by others. However, S1 nuclease mapping and subsequent genomic analysis allowed us to know that the clone possesses two more sites corresponding to 5'-termini in the 5'-noncoding region and another site of polyadenylation in the 3'-noncoding region. In fact, the major aldolase B mRNA species occupying 90% of the total mRNAs initiated at the predominant position corresponding to the position around -82 of the 5'-noncoding sequence in pHABL120-3 and terminated at the distal polyadenylation site. Second species accounting for 9% of the mRNAs initiated at the same site and terminated at the proximal polyadenylation site. The remainings have a longer 5'-noncoding sequence which starts from further upstream region of the major one and pHABL120-3 corresponds to one of these largest clones.

Amino Acid Sequence↗
PubMed1985

Determination of protein spots separated by two-dimensional polyacrylamide gel electrophoresis.

A simple method for quantitating proteins in the spots on two-dimensional polyacrylamide gel electropherograms is described. The system consists in three steps: (1) O'Farrell's two-dimensional gel electrophoresis of the proteins to be analysed; (2) staining of the gels with Coomassie brilliant blue; and (3) determination of the area and integrated density of the stained spots by the Joyce Loebl Magiscan-1 image analysis system. The method can be used for the determination of proteins in the range 0.5-100 micrograms/cm2; the amount of protein involved in most spots detected by the staining method actually falls within this range. As the minimum spot diameter that can easily be handled by the method is about 2 mm, as much as 30 ng of protein in such a spot can be determined. The method can also be applied to autoradiograms.

Autoradiography↗
PubMed1985

Structure and genomic organization of the rat aldolase B gene.

The structure of the chromosomal gene encoding rat aldolase isozyme B has been elucidated by sequence analysis of cloned genomic DNA. This gene comprises about 14 X 10(3) base-pairs of DNA, and is separated into nine exons by eight intervening sequences. A presumed transcription-initiation site was assigned by S1 nuclease protection mapping, and T-A-T-A and C-C-A-A-T boxes were found to be 25 and 126 base-pairs, respectively, upstream from this initiation site. There are three characteristic sequences of 100 to 200 base-pairs within the region of 870 base-pairs flanking the 5' side of the gene. These sequences are flanked on either side by direct repeats and terminate with an A-rich stretch of nucleotides. One of them has block homology with a region in an "ID sequence", which is reported to be an element for tissue-specific gene regulation and differentiation. The other two are analogous at the sequence organizational level with a sort of dispersed repeat, the "Alu family". These features suggest that these regions are involved in gene regulation and, also, imply evolutionary events such as duplication or insertion. Comparison of this gene sequence with the rabbit aldolase A complementary DNA sequence revealed some bias in the frequency of nucleotide replacement among the exons, suggesting selective evolutionary conservation of particular exons encoding functional domains. Comparison with the human aldolase B complementary DNA sequence revealed no such tendency; the homology between the two sequences was very high (about 89%), and nucleotide replacements were randomly distributed throughout the protein-coding region.

Animals↗
PubMed1985

Rat aldolase A messenger RNA: the nucleotide sequence and multiple mRNA species with different 5'-terminal regions.

The nucleotide sequence of aldolase A mRNA in rat skeletal muscle was determined using recombinant cDNA clones and a cDNA synthesized by primer extension. The sequence is composed of 1343 nucleotides (nt) except for the poly(A) tail. Based on the sequence analysis we have deduced an open reading frame with 363 amino acids (aa) (Mr 39134). The sequence suggests several nt polymorphisms in the mRNA population, one of which causes an aa change. The determined sequence of rat aldolase A mRNA was compared with the published ones of rabbit aldolase A or rat aldolase B mRNAs. The homology between rat and rabbit aldolase A mRNA sequences is greater than that between rat aldolase A and B mRNA sequences. Multiple aldolase A mRNAs having different Mrs were detected in the various tissues, and appeared to be expressed in a tissue-specific manner. Further analysis suggests that differences in mRNA length are due to differences in the 5'-noncoding terminal region.

Animals↗
PubMed1985

Rapid change in mutation rate in a local population of Drosophila melanogaster.

The lethal and detrimental loads per second chromosome rapidly increased from 1968 to 1970 in a local population of Drosophila melanogaster in Japan (lethal load, from about 0.16 to 0.38; detrimental load, from 0.125 to 0.231 [Watanabe, T. K., Watanabe, T. & Oshima, C. (1976) Evolution 30, 109-118]). When the homozygous loads were measured in 1983, the lethal load had decreased to approximately the original amount (0.19) but the detrimental load had stayed high (0.241). The rise and fall of the lethal load can be accounted for by a P-type element that invaded a population with M cytotype, producing a high mutation rate. The mutation rate fell back to the earlier value after the cytotype became P. That the detrimental load did not decrease can be explained by assuming a longer persistence for detrimental mutations in the population. Evidence for a P-type mutator factor is that the mutation rate of the wild-type chromosomes differs between the different cytoplasmic and chromosomal backgrounds, being lower in the background from which the chromosomes were taken.

Animals↗
PubMed1985

[Evaluation of myocardial viability in myocardial infarction by thallium-201 emission computed tomography].

Stress thallium-201 emission computed tomography (ECT) was performed for 24 patients with myocardial infarction for quantitative evaluation of regional thallium redistribution and washout. ECT was performed using a rotating gamma camera 10 minutes and 2.5 hours after thallium injection during maximal exercise. Three short-axis sections and one central long-axis section were selected for the circumferential profile curves. Redistribution (%) and washout (%) were calculated from the stress and redistribution profile curves in each section. These parameters were evaluated by comparison with regional wall motion on radiographic contrast ventriculography. Forty-eight of the 52 segments (92%) with normal thallium uptake showed normal wall motion. Among the segments with abnormal thallium uptake, normal or hypokinetic wall motion was observed in 12 of 13 segments (92%) with more than 20% redistribution and in 16 of 19 segments (84%) with 10-20% redistribution, while it was observed in only 15 of 36 segments (42%) without redistribution (p less than 0.001). Among 48 infarcted segments, 16 segments (33%) showed significant redistribution on ECT analysis. Normal or hypokinetic wall motion was observed in three of five segments (60%) with more than 20% redistribution, and in 10 of 11 segments (91%) with 10-20% redistribution, while it was seen in only eight of 30 segments (17%) without redistribution (p less than 0.005).

Heart↗
PubMed1985

[Aldolase isozyme gene: on the structure and the tissue-specific expression of a muscle type aldolase gene].

A muscle-type aldolase gene known to be a tumor marker enzyme was analyzed. It was found that three different molecular species of the mRNA exist and are expressed in a tissue-specific manner. These mRNAs have identical coding and 3' noncoding sequences and differ only at the 5' end of the sequence. Genomic DNA analysis indicated that a single aldolase gene for one muscle type specifies three different mRNAs by organizing as a leader sequence a region corresponding to each distinct 5' end of the mRNA followed by a shared common structural gene in the genome.

Animals↗
PubMed1984

Nucleotide sequence of rat liver aldolase B messenger RNA.

The nucleotide sequence of messenger RNA encoding rat liver aldolase B has been determined by sequence analysis using recombinant cDNAs cloned in bacterial plasmids. The sequence contains part of the 5'-untranslatable region (68 nucleotides), the entire coding region (1092 nucleotides), and the complete 3'-untranslatable region (387 nucleotides), excluding the poly(A) tail. A potential ribosomal-binding site is located about 30 nucleotides upstream from the initiation codon. The amino acid sequence of rat liver aldolase B is composed of 364 amino acids and has 70% homology with rabbit muscle aldolase A.

Amino Acid Sequence↗
PubMed1984

Different expression of rat aldolase A mRNA in the skeletal muscle and ascites hepatoma cells.

Rat aldolase A mRNAs from the skeletal muscle and ascites hepatoma cells are compared by RNA blot hybridization. The hepatoma AH60C and AH130 mRNA are about 1600 bases long, some 50 bases longer than the skeletal muscle transcript. Aldolase A enzymes encoded by these mRNAs, however, are indistinguishable in electrophoresis on cellulose polyacetate strips and two-dimensional polyacrylamide gel. In addition, comparison of the thermal stability of hybrids between the mRNAs from the skeletal muscle and hepatoma cells and a cDNA probe (pRAAM83) made from the aldolase A mRNA of the skeletal muscle indicate that the mRNAs have extremely high sequence homology, at least, within the most part of coding region in addition to the 3' noncoding region. These findings indicate that these mRNA may be transcribed by the use of different promoter sites and the common structural gene.

Animals↗
PubMed1984

A case report of pancreatic metastasis of an intracranial angioblastic meningioma (hemangiopericytoma) and a review of metastatic tumor to the pancreas.

The authors report a case of solitary metastasis to the pancreas from an intracranial angioblastic meningioma (hemangiopericytoma) and discuss secondary (metastatic) tumors of the pancreas. A 65-year-old man developed a pancreatic tumor 15 years after the craniotomy was performed for a parasagittal meningioma. Histological investigation of the pancreatic tumor excised as a biopsy on exploratory laparotomy revealed a tumor identical to the intracranial meningioma. It was concluded that the intracranial angioblastic meningioma had recurred and metastasized to the pancreas.

Aged↗
PubMed1984

Segmental analysis of stress thallium myocardial emission tomography for localization of coronary artery disease.

The value of stress thallium 201 myocardial emission computed tomography (ECT) in the assessment of coronary artery disease (CAD) was analyzed in 75 patients admitted for coronary arteriography. The ECT provided contiguous transaxial, short-axis, and long-axis sections of the myocardium and the myocardial images were divided into nine segments. The sensitivity and specificity in the diagnosis of CAD were 95% and 93%, respectively. Using selected segments, the ECT identified 97 of 111 (83%) major vessels involved: 89% for right coronary artery (RCA), 88% for left anterior descending (LAD), and 70% for left circumflex (LCx). Among the 75 cases, 35 underwent stress conventional planar imaging within 3 months. The planar imaging provided high sensitivity (90%) and specificity (100%) for the detection of CAD patients as well, but it showed lower sensitivity (57%, P less than 0.001) in identifying individual vessels involved: 55% for RCA (P less than 0.01), 70% for LAD, and 36% for LCx (P less than 0.05). Stress ECT detected vessel involvement more in two-vessel disease (85%) and three-vessel disease (78%) than the planar imaging (50%: P less than 0.05 and 44%: P less than 0.01, respectively). Thus, segmental analysis of stress ECT yielded as high sensitivity and specificity in the diagnosis of CAD as the planar imaging. This can improve sensitivity in identifying individual vessels involved in deep myocardial regions, especially in those with multivessel disease.

Adolescent↗
PubMed1984

Clinical evaluation of 99mTc-pyrophosphate myocardial emission computed tomography: comparison with planar imaging.

To depict the three-dimensional distribution of 99mTc-pyrophosphate in the heart, emission computed tomography (ECT) was performed, following the conventional planar imaging, in 32 cases with suspected acute myocardial infarction (AMI). There were 23 cases with evidence of AMI, 7 with unstable angina (UA), and 2 with dilated cardiomyopathy (DCM). While the planar images showed discrete cardiac activity in only 11 of the 23 cases (48%) with AMI, the ECT images delineated focal myocardial uptake clearly in 20 of them (87%). On the other hand, the ECT images revealed cardiac blood-pool activity without significant myocardial uptake in all cases with UA and DCM in which the planar images showed diffuse activity. Thus, the ECT imaging of 99mTc-pyrophosphate seems to be a valuable technique for assessing the presence and localization of myocardial necrosis, especially in cases showing diffuse cardiac activity in the planar imaging.

Adult↗
PubMed1984

Quantitative evaluation of tricuspid regurgitation by digital simulation of cardiac time-activity curves.

To estimate tricuspid regurgitation (TR) quantitatively, a curve fitting method by computer has been employed. Transport in the right cardiac chambers after intravenous bolus injection of macro-aggregated albumin labeled with technetium 99m (99mTc-MAA) was recorded in anterior view by a gammacamera system. Disturbance of the dilution curves from the left heart can be avoided by using 99mTc-MAA injection. To know the radioisotope activity during the transport, time-activity curves are recorded for the superior vena cava, right atrium, and right ventricle. Parametric differential equations, obtained from compartmental analysis, interpret these curves mathematically. The rate of regurgitation is determined by comparison, using an iterative process, between the original and simulated curves. The whole process is performed automatically by computer. The calculated regurgitation value correlated well with the value from the analog simulation. The method clearly separated those with TR from those without TR. This digital simulation for estimating parameters using a compartmental model is a feasible tool in detecting and quantifying TR.

Computers↗