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Biomedical subjects

R S Goldsmith

Publications and source records attributed to R S Goldsmith.

At least 37 records · Page 2Linked to original sources
PubMed1979

Calcium, phosphate, and vitamin D.

It is evident that there has been enormous progress within the last decade in our understanding of vitamin D metabolism and its interaction with calcium, phosphate, parathyroid hormone, and a number of other factors. As a result largely of therapeutic trials with various metabolites of vitamin D, we now know something of their probable involvement in the development of rickets and osteomalacia. We do not yet have a clear comprehension of exactly how these metabolites influence bone mineralization other than through their indirect effect on serum calcium and phosphate. Nonetheless it seems likely that at least one, and perhaps more, of the metabolites do exert a more direct effect. One must conclude that a deficiency of the 1alpha-hydroxylase is probably not the only defect in renal insufficiency, although it currently that there must well known. It is premature to go so far as to suggest that there must be another metabolite not being synthesized in the diseased or absent kidney.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1979

Seroepidemiologic studies in Oaxaca, Mexico. II. Survey for arbovirus antibody.

A serologic survey was conducted in south-western Mexico to obtain information on human experience with arbovirus infections. Sera were collected from two semitropical areas along the Pacific coast of Oaxaca State, two mountain areas above 1,700 meters and the interior valley at 1,500 meters. Of the 610 sera tested for group A antibody, 4.9 per cent were positive in the hemagglutination-inhibition (HI) test to Venezuelan (VE), 11 per cent to Eastern, and none to Western encephalitis viruses. In neutralization tests the antibody was shown to be probably due to VE virus infections. When sera were screened for group B antibodies in the HI test, 32 per cent were positive with St. Louis encephalitis (SLE), 19 per cent with Ilhéus, and 4 per cent with yellow fever viruses. The pattern of reactions suggested that SLE or an antigenically related virus was responsible for the antibody detected. An unusually high rate was found in a mountain area at 2,000 meters: 41 per cent of 113 persons tested were seropositive to SLE. Of 493 sera screened by complement-fixation test, 6 per cent were positive to Nepuyo, 4 per cent to Patois, and 3 per cent to Tlacotalpan viruses.

Adolescent↗
PubMed1978

Chronic diarrhea in returing travelers: intestinal parasitic infection with the fluke Metagonimus yokogawai.

An unusual intestinal infection with the parasite Metagonimus yokogawai was acquired by an American traveling in the Orient. Diarrhea began abroad, and recurred at intervals until she was seen 1 1/2 years later. Stool examinations resulted in the recovery of small operculated ova characteristic of intestinal or biliary fluke infection. Treatment with hexylresorcinol failed to eradicate the infection, but subsequent use of tetrachloroethylene was successful and facilitated recovery of adult parasites, leading to the specific diagnosis of metagonimiasis. Metagonimiasis and related intestinal fluke infections should be considered as a possible cause of persistent diarrhea in travelers returning from endemic areas abroad.

Chronic Disease↗
PubMed1978

Calcium flux during hemodialysis.

A system of equations has been derived, and examined, to decribed membrane permeability and calcium fluxes within a commonly used hemodialyzer, the Mini-Kiil. By a statistical technique of sequential multiple regression analysis, factors which might influence these variables were tested on data derived from 74 hemodialysis periods in 5 patients. Calcium flux from plasma to dialysate was influenced positively by dialysate calcium concentration and plasma volume flow and negatively by dialysate volume flow. Calcium flux from dialysate to plasma was influenced positively by dialysate calcium concentration and plasma volume flow and negatively by plasma phosphate concentration. Net calcium flux from dialysate to plasma was influenced positively by the calcium gradient (dialysate calcium minus plasma ultrafiltrable calcium) and plasma volume flow and negatively by plasma phosphate concentration (coefficient of multiple correlation =0.970). Because of the magnitude of regression coefficients, manipulations of the dialysate calcium concentration and plasma phosphate concentration were concluded to be the most practical means of adjusting calcium delivery during dialysis.

Calcium↗
PubMed1977

Components of 25-hydroxyvitamin D in serum of young children in upper midwestern United States.

The relative importance of cholecalciferof (vitamin D3) and ergocalciferol (vitamin D2) in maintaining the vitamin D level in children (1/2 to 6 years old) living in the upper midwestern United States was determined by measurement of total 25-hydroxyvitamin D (25-OH-D), its components, and other indices of calcium homeostasis in serum. In 38 normal children, mean (range) serum total 25-OH-D was 32.8 (less than 5 to 53) ng/ml; in 25 of the 28 sera partitioned, the major component was 25-OH-D3. Significant seasonal variation in serum 25-OH-D3 (mean, range: 35.2, 17 to 51 ng/ml in summer and 15.9, less than 5 to 32 ng/ml in winter) was not accompanied by changes in mean serum 25-OH-D2, calcium, phosphorus, or alkaline phosphatase values. However, individual serum total 25-OH-D values correlated with serum phosphorus values (r = 0.37; P less than 0.05). The proportion of the total represented by 25-OH-D3 varied widely, with a a mean of 83% in summer and 67% in winter. Sources of D3, which include both dermal synthesis and intestinal absorption of D3 added to milk, appear to be more important than sources of D2 in maintaining vitamin D nutrition of young children throughout the year. However, sources of D2 offset the decrease in total 25-OH-D in winter months.

Alkaline Phosphatase↗
PubMed1976

Dietary protein intake and dynamic aspects of whole body nitrogen metabolism in adult humans.

The constant isotope-infusion method of Picou and Taylor-Roberts was used to study rates of total body protein synthesis and breakdown in adult subjects following acute changes in the level of dietary protein intake. Six healthy adults, four males and two females, were studied after adaptation to dietary protein intakes of 1.5 and 0.38 g of protein/kilogram body weight/day. Dietary periods were from 7 to 15 days duration. 15N-glycine was used as a tracer, and was administered orally for 60 hr at 3-hr intervals, or by continuous intravenous infusion for 48 hr. Results were similar for both routes of isotope administration for the comparison conducted at the higher protein intake. At the 1.5-g protein level the mean N flux was 28.2 mg nitrogen/kg/hr, with total body protein (N x 6.25) synthesis and breakdown rates being 3.0 g/kg/day and 2.7 g/kg/day, respectively. Reducing the protein intake to 0.38 g/kg/day caused an 8% decrease (p less than 0.05) in N flux, a 27% increase (p less than 0.005) in the rate of total body protein breakdown, and a 15% increase (p less than 0.05) in the rate of protein synthesis. Endogenous amino acids were reutilized more efficiently under these conditions. The findings are discussed in relation to the way in which adult subjects adapt to acute changes in dietary protein intake.

Adaptation, Physiological↗
PubMed1976

The effects of calcium and phosphorus in hemodialysis.

Combined use of Ca supplements (orally or by dialysis) to circumvent decreased intestinal Ca absorption and aluminum compounds to reduce plasma [Pi] has been demonstrated to decrease plasma [iPTH], to normal or near normal in many patients, and to decrease the percentage of bone surface involved in bone resorption. A highly significant positive relationship between change in plasma [iPTH] and bone resorbing surface has been reported. It seems evident, therefore, that PTH must be a major factor in the bone resorption of chronic renal failure, despite the relative skeletal resistance to PTH. As a result, correction of factors that increase PTH secretion should be considered a prime goal of therapy in these patients. The osteomalacic element of renal osteodystrophy, on the other hand, is only partially controlled by these maneuvers and probably requires the additional use of vitamin D or one of its active metabolites for full correction.

Animals↗
PubMed1976

Effects of phosphorus supplementation on serum parathyroid hormone and bone morphology in osteoporosis.

The effect of phosphorus (inorganic phosphate) supplementation was studied in seven postmenopausal women with osteoporosis. Prior to supplementation, all chemical parameters studied in serum and urine were normal. Bone density was below the fifth percentile for age in all but one patient, and the percentage of bone surface involved in resorption was higher than normal. During administration of the phosphorus supplement, fasting serum concentrations of calcium and immunoreactive parathyroid hormone showed no significant changes, while serum phosphorus, urinary calcium, and tubular reabsorption of phosphorus decreased. In four patients studied by balance techniques, calcium balance became positive or less negative. Bone-forming surface decreased and bone-resorbing surface increased in all patients. Bone-resorbing surface was highly correlated with total phosphorus intake. Density of the distal radius changed variably, while density of the midradius increased slightly in all patients.

Aged↗
PubMed1976

Plasma ionic calcium levels following injection of chloride, gluconate, and gluceptate salts of calcium.

The ionic equivalency of three calcium salts was tested in 15 patients undergoing cardiac surgery with extracorporeal circulation. Of the three salts tested (chloride, gluconate, gluceptate), only calcium chloride showed a reproducible and highly significant relationship between the increase in total calcium and the increase in ionic calcium. It is suggested that extracorporeal circulation may be one clinical situation in which use of a calcium electrode may be of major value. The marked distortion of plasma proteins and pH, the addition of large amounts of citrate, and the differences between various calcium salts indicate that it is probably not possible to predict ionic calcium with assurance and that direct measurement may be necessary for optimal therapy.

Buffers↗