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Biomedical subjects

K Kamide

Publications and source records attributed to K Kamide.

23 records · Page 2Linked to original sources

Links between hypertension and myocardial infarction.

The mechanisms through which hypertension contributes to the occurrence of myocardial infarction should be discussed from two points of view: (1) common risk factors for the two diseases, such as genetic risk, insulin resistance, sympathetic hyperactivity, and vasoactive substances such as angiotensin K, and (2) linking factors that are induced by hypertension and contribute to the development of atherosclerosis and myocardial infarction, such as atherosclerosis and left ventricular hypertrophy. Mechanical stress on blood vessels because of high blood pressure is an especially important factor in endothelial dysfunction, the progression of atherosclerosis, and plaque rupture. This article concentrates on these factors from the perspective of their relationship with the renin-angiotensin system, because recent multicenter trials have demonstrated that angiotensin-converting enzyme inhibitors are effective for preventing recurrence of myocardial infarction.

Arteriosclerosis↗

Ferredoxin and ferredoxin-NADP reductase from photosynthetic and nonphotosynthetic tissues of tomato.

Ferredoxin and ferredoxin-NADP+ oxidoreductase (FNR) were purified from leaves, roots, and red and green pericarp of tomato (Lycopersicon esculentum, cv VFNT and cv Momotaro). Four different ferredoxins were identified on the basis of N-terminal amino acid sequence and charge. Ferredoxins I and II were the most prevalent forms in leaves and green pericarp, and ferredoxin III was the most prevalent in roots. Red pericarp of the VFNT cv yielded variable amounts of ferredoxins II and III plus a unique form, ferredoxin IV. Red pericarp of the Momotaro cv contained ferredoxins I, II, and IV. This represents the first demonstration of ferredoxin in a chromoplast-containing tissue. There were no major differences among the tomato ferredoxins in absorption spectrum or cytochrome c reduction activity. Two forms of FNR were present in tomato as judged by anion exchange chromatography and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. FNR II had a lower apparent relative molecular weight, a slightly altered absorption spectrum, and a lower specific activity for cytochrome c reduction than FNR I. FNR II could be a partially degraded form of FNR I. The FNRs from the different tissues of tomato plants all showed diaphorase activity, with FNR II being more active than FNR I. The presence of ferredoxin and FNR in heterotrophic tissues of tomato is consistent with the existence of a nonphotosynthetic ferredoxin/FNR redox pathway to support the function of ferredoxin-dependent enzymes.

Amino Acid Sequence↗

Characterization and N-terminal sequence of a 5 kDa polypeptide in the photosystem I core complex from spinach.

Photosystem I core complexes were isolated from spinach photosystem I particles after heat treatment in the presence of 50% (v/v) ethylene glycol (heat/EG treatment). The core complex from 58 degrees C/EG-treated particles was composed of polypeptides with apparent molecular masses of 63, 60 and 5 kDA; this complex contained the iron sulfur center Fx but lacked center FA and FB. The core complex obtained from the 70 degrees C/EG-treated preparation lacked FX and contained a lesser amount of the 5 kDa polypeptide. The N-terminal amino acid sequence of the 5 kDa polypeptide did not correspond to the sequence derived from any possible reading frame in the chloroplast DNA of liverwort or tobacco. Twelve of the first 29 N-terminal amino acids were hydrophobic, suggesting that this protein is intrinsic to the photosystem I reaction center.

Amino Acid Sequence↗