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Biomedical subjects

R Smith

Publications and source records attributed to R Smith.

At least 1,297 records · Page 72Linked to original sources
PubMed1984

Studies of the hypercalcaemia of sarcoidosis: effect of steroids and exogenous vitamin D3 on the circulating concentrations of 1,25-dihydroxy vitamin D3.

Hypercalcaemia in six patients with sarcoidosis was associated with elevated circulating 1,25-dihydroxy vitamin D3 (187-475 pmol/l): the concentration of this metabolite of vitamin D was a function of the concentration of its precursor, 25-hydroxy vitamin D which remained within the normal range. Corticosteroids, in reducing serum calcium, eliminated this abnormal substrate--product relationship by rapidly reducing circulating 1,25-dihydroxy vitamin D3 while having no effect on 25-hydroxy vitamin D. The fall in circulating 1,25-dihydroxy vitamin D3 preceded the fall of calcium. Studies on the clearance of exogenous 1,25-dihydroxy vitamin D3 indicated that during hypercalcaemic episodes, the plasma disappearance time of the sterol was delayed and that this reverted to normal with steroid therapy. Administration of vitamin D3 to these patients with sarcoidosis increased the circulating concentration of 1,25-dihydroxy vitamin D3 and this resulted in hypercalcaemia, thus accounting for their hypersensitivity to vitamin D and sunlight.

Adult↗
PubMed1984

Hypercalcaemia. Presentation.

The symptoms produced by hypercalcaemia are often sufficiently specific for the disorder to be suspected from the history alone; and in most instances appropriate enquiry will make it possible to establish the most likely cause.

Calcinosis↗
PubMed1983

Endorphin-related peptides in rat cerebrospinal fluid.

Cerebrospinal fluid (CSF) samples were taken from rats implanted with chronic cisternal cannulae and assayed for methionine-enkephalin, beta-endorphin and corticotropin (ACTH). Immobilization stress had little apparent effect on immunoreactive levels of the peptides in the CSF. Gel chromatographic analysis of the beta-endorphin- and ACTH-immunoreactive profiles in rat CSF revealed several peaks. beta-Endorphin-immunoreactive peaks were present at the expected positions of pro-opiocortin, beta-lipotropin and beta-endorphin. ACTH-immunoreactive peaks eluted at positions corresponding to pro-opiocortin, the 20-23K ACTH biosynthetic intermediate, 14K ACTH, and 4.5K ACTH. These results suggest that rat CSF contains peptides of the pro-opiocortin family similar to those previously described in rat pituitary.

Adrenocorticotropic Hormone↗
PubMed1983

Crisis upon crisis.

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Costs and Cost Analysis↗
PubMed1983

Shark CNS myelin contains four polypeptides related to the PNS protein Po of higher classes.

The relationship between the proteins of shark central nervous system (CNS) myelin and those of myelin from higher classes has been investigated using antibodies raised against a 31,500 molecular weight polypeptide from shark myelin. The antibodies cross-reacted with 3 shark CNS polypeptides apart from the original antigen, with 2 major polypeptides from shark peripheral nervous system myelin, with the Po protein from chicken and sheep peripheral nervous system myelin, but with none of the components of bovine CNS myelin. It appears that the oligodendroglial cells of the shark synthesize a protein closely related to the Po protein produced by Schwann cells of vertebrate classes above and including chondrichthytes.

Animals↗
PubMed1983

Coronary care at Hutt Hospital 1980-1981.

Three hundred and forty-one patients were admitted to the coronary care unit, Hutt Hospital during twelve months from 1980-1981. Of the 60 with myocardial infarction, 75% developed symptoms at home, 49% came to hospital without first seeing a doctor and 60% arrived by ambulance. The median admission delay from onset of symptoms of infarction was 3.4 hours, one hour of which was spent in the A and E department. Only 5% of all admissions were defibrillated in the coronary care unit. The higher mortality with infarction in older patients was confirmed. The practical implications of our findings are discussed.

Adult↗
PubMed1983

31P nuclear magnetic resonance studies of the association of basic proteins with multilayers of diacyl phosphatidylserine.

Lysozyme, cytochrome c, poly(L-lysine), myelin basic protein and ribonuclease were used to form multilayer dispersions containing about 50% protein (by weight) with bovine brain diacyl phosphatidylserine (PS). 31P nuclear magnetic resonance shift anisotropies, spin-spin (T2) and spin-lattice (T1) relaxation times for the lipid headgroup phosphorus were measured at 36.44 MHz. At pH 7.5, lysozyme, cytochrome c, poly(L-lysine) and ribonuclease were shown to increase the chemical shift anisotropy of PS by between 12-20%. Myelin basic protein altered the shape of the phosphate resonance, suggesting the presence of two lipid components, one of which had a modified headgroup conformation. The presence of cytochrome c led to the formation of a narrow spike at the isotropic shift position of the spectrum. Of the various proteins or peptides we have studied, only poly(L-lysine) and cytochrome c had any effect on the T1 of PS (1050 ms). Both caused a 20-30% decrease in T1 of the lamellar-phase phosphate peak. The narrow peak in the presence of cytochrome c had a very short T1 of 156 ms. The possibility is considered that the cytochrome Fe3+ contributes to the phosphate relaxation in this case. The effect of all proteins on the T2 of the phosphorus resonance was to cause an increase from the value for pure PS (1.6 ms) to between 2 and 5 ms. The results obtained with proteins are compared with the effects of small ions and intrinsic membrane proteins on the order and motion of the headgroups of lipids in bilayers.

Animals↗
PubMed1983

Biological membranes are rich in low-frequency motion.

Using 13C cross-polarization NMR techniques, we have found that the effect of protein on the dynamics of the hydrocarbon interior of a series of biological membranes is to depress the intensity of motion on the nanosecond timescale (i.e., T1 becomes longer) and to enhance the intensity of motion on the timescale of tens of microseconds (i.e., T1p becomes shorter.)

Animals↗