Biomedical subjects
Publications and source records attributed to M Sakai.
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We have used a rat glutathione S-transferase P (GST-P) complementary DNA as a probe to screen a human placenta complementary DNA library constructed in the lambda gt11 vector. One of the positive clones contained the complete coding region (630 base pair) and the entire 3'-noncoding region (78 base pair) of the putative human glutathione S-transferase pi (GST-pi) subunit mRNA. From the nucleotide sequence we deduced the complete amino acid sequence of the GST-pi subunit. It contained 209 amino acids with the relative molecular mass of Mr 23,224. Comparison of the amino acid sequences between GST-pi and GST-P subunits suggests that they are the corresponding enzymes in these species. GST-pi and GST-P both consist of 209 amino acids and differ in only 30 amino acids (85.6% homology). The difference in amino acid composition can explain the large difference in isoelectric point between GST-pi subunit (pI 5.5) and GST-P subunit (pI 6.9). The expression of GST-pi mRNA in some normal and cancerous tissues, including some hepatoma cell lines, hepatoma, and colon carcinoma specimens was determined using complementary DNA as a probe. The results indicate that the mode of the expression of GST-pi in humans is different from that of GST-P in rats.
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For the purpose of characterizing the estrogen binding domain of porcine estrogen receptor (ER), we have made use of affinity labeling of partially purified ER with [3H]tamoxifen aziridine. The labeling is very efficient and selective particularly after partial purification of ER. A 65,000-dalton (65-kDa) band was detected on the fluorogram of a sodium dodecyl sulfate-polyacrylamide gel, together with a 50-kDa band and a few more smaller bands. The 50-kDa protein appears to be a degradation product of the 65-kDa protein in view of the similar peptide map. ER was affinity labeled before or after controlled limited proteolysis with either trypsin, papain, or alpha-chymotrypsin. The labeling patterns of limited digests indicate that a fragment of about 30 kDa is relatively resistant to proteases and has a full and specific binding activity to estrogen, whereas smaller fragments have lost much of the binding activity. This fragment is very hydrophobic and probably corresponds to the carboxy half of ER.
Antisera raised against glutamate or aspartate bound to bovine serum albumin were purified by affinity chromatography, and their specificities were verified by immunoblotting and by enzyme-linked immunosorbent assay. Immunohistochemical investigation using materials perfusion-fixed after long flushing demonstrated distinct laminar terminals with glutamate- or aspartate-like immunoreactivity throughout the limbic structures. This technique may offer a valuable tool for revealing the distribution of glutamatergic or aspartatergic nerve terminals.
A cDNA clone of rat uterus estrogen receptor (ER) has been isolated and sequenced. This clone contains a complete open reading frame encoding 600 amino acid residues which is 5 and 11 amino acids larger than the corresponding molecules of human and chicken, respectively. The molecular weight of this protein is calculated to be 67,029. When this clone was ligated to the pSV2 vector and transfected into COS7 cells, a protein was produced that had the same affinity to estrogen as rat uterus ER. This sequence shows 88% homology with human ER; 528 amino acids are identical and 14 amino acids are conservative substitutions. The comparison of rat, human and chicken ER sequences indicate the presence of three highly conserved regions suggesting that these regions play important roles in ER function. The putative DNA-binding domain is completely identical in rat, human and chicken. The C-terminal half region which is thought to be the estrogen binding domain is also highly conserved and is rich in hydrophobic amino acid residues. Southern blot analysis of genomic DNA with ER cDNA as a probe has shown that related sequences are present in the genome.
Using the peroxidase-antiperoxidase immunohistochemical technique, carnosine-like immunoreactivity was demonstrated to localize specifically within the primary olfactory neuron.
We have isolated the rat placental-type glutathione S-transferase (GST-P) gene from a lambda phage library using GST-P cDNA clone, pGP5 (Sugioka, Y., Kano, T., Okuda, A., Sakai, M., Kitagawa, T., and Muramatsu, M. (1985) Nucleic Acids Res. 13, 6049-6057), as a probe. The rat GST-P gene is about 3 kilobase pairs long and contains 7 exons and 6 introns, encoding the same GST-P protein specified by pGP5. The cap site maps 70 nucleotides upstream from the translation initiation site. The canonical promoter "TATA" box was found 27 base pairs upstream from the putative cap site. Two hundred base pairs upstream from the cap site are rich in G + C residues (61%), and the hexanucleotide sequence 5'-GGGCGG-3' is found at position -47 to -42. We have also isolated several processed-type pseudogenes which were presumably originated by reverse transcription followed by insertion at target sites.
Effects of alpha-human atrial natriuretic polypeptide (alpha-hANP) on neuronal membrane-bound adenosine triphosphatases (ATPases) (Na, K-ATPase, Cl-stimulated Mg-ATPase and anion-insensitive Mg-ATPase) were examined using rat brain microsomes. This peptide inhibited Cl-stimulated Mg-ATPase in a dose-dependent manner. The inhibition was non-competitive with respect to ATP, and was not affected by Cl-, the most potent stimulator of this enzyme. The activities of Na,K-ATPase and anion-insensitive Mg-ATPase were not changed by alpha-hANP at all.
Neuroendocrine functions in depressed patients with major affective disorders were serially investigated by the Dexamethasone Suppression Test (DST), the thyrotropin-releasing hormone (TRH) stimulation test, and the plasma TRH-like immunoreactivity (TRH-LI) measurement. Prior to antidepressant therapy, the sensitivity for nonsuppression to the DST was 36.0%, whereas that for blunted thyroid-stimulating hormone (TSH) response to TRH was 28.0%. Both DST nonsuppression and TSH blunting appeared to be state-related markers for depressed patients. Specifically, a significant increase of maximum TSH response to TRH after 4 weeks of antidepressant therapy was associated with clinical improvement. Plasma TRH-LI in depressed patients was significantly lower than that of healthy controls. It is possible that the lower plasma TRH-LI level is related to the pathophysiology of some depressed patients with major affective disorders.
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The portal hemodynamics were studied in ten patients with portal hypertension, including three patients who had interposition mesocaval shunt (IMCS), three patients who had distal splenorenal shunt (DSRS), one patient who had gastrocaval shunt (GCS), and three patients who had splenectomy. Portal blood flow was measured by an ultrasonic Doppler duplex system, and portal venous pressure was measured by portal catheterization before, during, and after operation. The portal blood flow, and especially the splenic venous blood flow, was less during operation than before operation. Blood flow through the IMCS was greater than that through the DSRS, and the shunt flow had a tendency to increase after operation. The portal venous pressure measured during operation was slightly higher than that measured percutaneously before operation. In the patients who had the shunt operation, the portal venous pressure tended to decrease after operation. Study of portal hemodynamics, especially with the ultrasonic Doppler method, is useful in analysis and follow-up of patients who have shunt operations since the same method can be used before, during, and after operation.
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To assess accurately the indication and effects of aorto-coronary bypass graft surgery (ACBG) to the myocardium infarction area, 35 patients with myocardial infarction were analyzed by using exercise thallium-201 myocardial imagings. The patients were classified into group I (18 cases) and group II (17 cases) before ACBG. Group I consisted of patients with regional hypoperfusion in the initial image who showed redistribution in the delayed image to the infarction area of myocardium. Group II consisted of those with regional hypoperfusion in the initial image without redistribution in the delayed image. Group I showed a significant improvement in myocardial perfusion (p less than 0.01), pressure rate product (p less than 0.01), global left ventricular ejection fraction (p less than 0.01), segmental wall motion abnormality (p less than 0.01), and exercise tolerance when compared with those of group II before and after ACBG. The above study showed that the pre- operative redistribution of the infarction area in the delayed image suggests myocardial viability and ACBG will be effective.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.