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Biomedical subjects

D Roy

Publications and source records attributed to D Roy.

At least 379 records · Page 21Linked to original sources
PubMed1976

Human alpha-crystallin: characterization of the protein isolated from the periphery of cataractous lenses.

alpha-Crystallin has been isolated from the peripheral region of old cataractous lenses. It was found to be closely related to bovine alpha-crystallin and to human newly synthesized alpha-crystallin in terms of its amino acid composition, the size of its polypeptide chains and the lack of free NH2-terminal groups. However, in contrast to the simple urea gel electrophoretic polypeptide patterns obtained with the reference proteins, 11 polypeptides were detected in the preparation. Ten of the polypeptides were isolated and shown to be either A or B chains on the basis of their amino acid compositions and comparison of the peptide maps of their tryptic hydrolysates. The four B chains as well as the six A chains were closely related, with most of the tryptic peptides being common to all members of their respective group. A nomenclature based upon the urea gel electrophoretic mobilites of the polypeptides has been proposed to define each chain. It was found that this alpha-crystallin preparation is composed of at least two populations of macromolecules, one of which contains macromolecules greater than 5 X 10(6) daltons on the basis of gel filtration with Bio-Gel A-5m. The compositions of the two fractions were found to be essentially identical.

Aged↗
PubMed1976

The response of the hospital doctor to the health requirements of a changing society.

Before the advent of the National Health Service in 1948 most hospital doctors were in close contact with the primary care of, at least, a section of the community both by their continuing close contacts with general practitioners and as a result of often having spent some part of their careers as general practitioners. Since 1948 this awareness of the health aspirations of the community has weakened as a result of advances in the care of disease which have made the hospital doctor increasingly dependent on sophisticated facilities and, thus, focused his attention on hospital care rather than on the community. Hospital staff must re-establish their link with primary care and must perceive clearly the ways in which they contribute to the health of their community. They must be conscious of the proportion of available resources that are used in hospital and be prepared to regulate demands so that there is equality in the distribution of resources in the health field. Hospitals are not only expensive but have become extravagant; it is the responsibility of the hospital doctor to curb extravagance. If private practice is to continue, it must be integrated into the health service, not excluded from it. Finally, the patient must be recognized as a member of a family and of a community that is both curious and concerned about health. The hospital doctor must communicate with patience, understanding and clarity. In this relationship he also has a part to play in health education and prevention of disease. He must remove the mystery from his art and enter into useful discussions with government and community.

Community Health Services↗
PubMed1976

Elevation of serum creatine kinase in severe hypokalemic hyperaldosteronism.

The association between hypokalemia and increased serum creatine kinase has been investigated. Two patients were found who had severe hypokalemic hyperaldosteronism who had elevation of serum creatine kinase activity. The CPK activity returned to normal values after fluid and potassium replacement. In a prospective study of 129 patients with hypokalemia which did not include any patients with hyperaldosteronism, 12 were found to have increased CPK activity but each of these had some other severe disease process which could account for the increased CPK. Three other patients with K+ (2.2 MEq/1 did not have increased CPK. It is concluded that patients with severe hypokalemia such as that occurring in hyperaldosteronism with muscle weakness may have elevated CPK directly related to their hypokalemia. In other patients with hypokalemia, 10% may have increased CPK but this is related to other disease processes.

Adult↗
PubMed1976

Absence of low-molecular-weight alpha crystallin in nuclear region of old human lenses.

Examination of old human lenses indicates that low-molecular-weight alpha crystallin is not present in the inner 30-40%, the nucleus, of the lens. The remainder of such lenses, the periphery, contains normal levels of this protein. This finding is in marked contrast to observations in young lenses, where a large quantity of this protein is found throughout the tissue.

Aging↗
PubMed1976

Human alpha-crystallin. I. The isolation and characterization of newly synthesized alpha-crystallin.

Studies of the incorporation of 14C amino acids into human lens proteins demonstrate that an alpha-crystallin fraction takes up more than six times as much radioactivity as any other lens protein. Based on analyses with a calibrated Bio-Gel A-1.5 m column, a molecular weight of 4.9 x 10(5) +/- 5 per cent was obtained for this protein while sedimentation equilibrium analyses indicated a weight average molecular weight, Mw, of 7.5 x 10(5) +/- 4 per cent at 10,000 r.p.m. Gel electrophoresis in sodium dodecyl sulfate revealed two components with molecular weights of 22,000 and 20,000, values similar to those found with calf alpha-crystallin. Alkaline urea gel electrophoresis indicated one major polypeptide with a mobility similar to the B2 chain of calf alpha-crystallin and two major bands with mobilities between those of the calf alpha-crystallin A2 and A1 chains. Amino acid analyses of this newly synthesized alpha-crystallin gave a composition which with a few exceptions is very similar to that of calf alpha-crystallin. All three major polypeptides contained 14C amino acids. However, from the present data, it cannot be determined whether the three polypeptides were independently synthesized or a rapid transformation produced one of the labeled polypeptides in the A region. There appears to be between three and four times as many presumptive A as B polypeptides.

Amino Acids↗
PubMed1976

Human alpha-crystallin-III isolation and characterization of protein from normal infant lenses and old lens peripheries.

Alpha-crystallin isolated from the peripheries of old normal or cataractous lenses appears to be identical, consisting of eleven polypeptides, five B, and six A chains. In contrast, alpha-crystallin isolated from normal six-week-old human lenses has only three major polypeptides, corresponding to B1, A1, and A2 of the old human lens protein as well as small amounts of some of the other components. Comparisons with bovine alpha-crystallin are also reported. Based on gel filtration experiments with Bio-Gel A-1.5m, two distinct populations of alpha-crystallin were found in old lens periphery, one containing species greater than 1.5 X 10(6) daltons and another of approximately 9 X 10(5) daltons. In the cataract preparations, the higher molecular weight fraction is predominant. This fraction is not present in young lenses.

Aged↗
PubMed1971

[The L.S.D. Trip].

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Identity Crisis↗