Nutritional effect of dairy protein concentrates on protein synthesis in vitro in rat skeletal muscle.
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Biomedical subjects
Publications and source records attributed to B Lund.
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Fifteen acromegalic subjects were found to have elevated plasma levels of both 1,25(OH)2-vitamin D, 65 +/- 23 (SD) pg/ml [normal 33 + 15 pg/ml (SD)] and 24,25(OH)2-vitamin D, 6.8 +/- 1.6 (SD) ng/ml [normal 3.4 + 1.2 ng/ml (SD)]. Treatment with bromocriptine for 6 months reduced the plasma 1,25(OH)2-vitamin D3 level to 40 +/- 13 (SD) pg/ml, p less than 0.01 and the 24,25(OH)2-vitamin D level to 5.4 +/- 1.7 (SD) ng/ml, p less than 0.05.
A sensitive assay is described for measurement of circulating 1,25-dihydroxyvitamin D (1,25-(OH)2D) using rachitic chick intestinal cytosol binding protein. The metabolite was extracted from serum by diethyl ether and chromotographed on a Sephadex LH-20 column followed by high-pressure liquid chromatography. The concentration of 1,25-(OH)2D was then measured by a competitive protein-binding assay. The binding capacity of the protein was unchanged for 4 months. The inter- and intra-assay variations were both 11%. The standard curve was useful at serum concentrations ranging from 14 to 395 pmol/l (6 to 165 pg/ml). The normal mean concentration was 79.6 +/- 36.8 pmol/l (33.1 +/- 15.3 pg/ml). The serum 1,25-(OH)2D was studied in elderly subjects following administration of 1 alpha-hydroxycholecalciferol (1 alpha-OHD3) at different doses. Large variations occurred indicating individual rates of metabolism of 1,25-(OH)2D.
Plasma concentrations of 1,25-dihydroxyvitamin D (1,25--(OH)2D), serum prolactin and serum parathyroid hormone (PTH) were followed during pregnancy and lactation in 16 women. High 1,25--(OH)2D was demonstrated in human pregnancy and lactation. A causative relationship between 1,25--(OH)2D and prolactin is discussed and a possible explanation of the mechanism of the augmented calcium absorption in human pregnancy and lactation is suggested.
A competitive protein-binding assay for 25-hydroxyvitamin D (25-OHD) based upon a specific binding protein in the cytosol from rachitic rat kidneys is described. A diethyl ether extraction followed by separation by freezing was used. The extracts were chromatographed on short silicic acid columns, which separated 25-hydroxycholecalciferol from cholecalciferol, 24,25-dihydroxycholecalciferol, and 1,25-dihydroxycholecalciferol. A small aliquot of the 25-OHD fraction was used in the assay and free and bound vitamin were separated by dextran coated charcoal. The lower detection limit was 0.8 ng/ml (2.0 nmol/l). The levels of 25-OHD were measured in 596 healthy subjects and a seasonal variation was demonstrated. This variation, however, was only found in those without regular vitamin D intake, whereas the level of 25-OHD remained constant throughout the year in subjects with regular vitamin D supplement. The levels of 25-OHD were lower in the elderly subjects compared to younger ones, but seasonal variation was observed in both groups. In the summer months there was a significant correlation between age and the 25-OHD level. The mean levels of 25-OHD in Denmark are within the range of means found in the United States and Sweden but are higher than those reported from England, Belgium and France. This indicates a relatively high vitamin D intake in the Danish population and a low risk of nutritional vitamin D deficiency.
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Vitamin D has been proposed as a risk factor of ischaemic heart disease. In 12 patients with acute myocardial infarction the major circulating vitamin D metabolite, 25-hydroxy-cholecalciferol (25-HCC), did not show any fluctuations during the first 4 days after onset of symptoms. The serum 25-HCC level was then measured in 128 patients consecutively admitted because of chest pain, 53 of whom had myocardial infarction and 75 had angina pectoris. The values found did not differ from those measured in 409 normal persons. The seasonal variations of serum 25-HCC were less pronounced in heart patients than in normals, probably due to less sun exposure in the summer months. The levels of serum 25-HCC did not correlate with the concentrations of serum cholesterol, glycerides, calcium or magnesium. Low serum calcium and magnesium were observed in all patients. Serum calcium was further reduced in the course of acute myocardial infarctions while serum parathyroid hormone rose significantly. We conclude that patients with ischaemic heart disease are not ingesting or producing in their skin elevated amount of vitamin D.
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Young adult rats (body weight 90 g) were given a low protein (3% casein) diet for 6 days. Under these conditions, thymus and spleen organ wet weights and DNA content decreased as compared with control rats given a high protein (20% casein) diet. The in vitro incorporation of amino acids into protein was followed using leucine as the radioactive precursor. Ribosomes of tissues from the dietary rats were incubated together with soluble enzymes from liver of rats fed a stock diet, and cofactors. Ribosomal capacity for leucine incorporation into protein diminished in thymus by 33% per mg ribosomal RNA, 77% per total ribosomal RNA, and 43% per mg DNA. In spleen the corresponding reductions were 29%, 81%, and 31%; in bone marrow the decrease was 29% per mg ribosomal RNA, 56% per total ribosomal RNA, and 19% per mg DNA. A reduction in physiological activity is thus evident in these tissues soon after protein restriction.
The purpose of this study was to investigate whether 600-800 ml of fresh autologous blood, withdrawn just before anesthesia and retransfused at the end of the operation, would reduce early postoperative anemia. Thirty-nine patients undergoing abdominal hysterectomy were autotransfused, while 44, submitted to the same operation, served as controls. Appropriate amounts of lactated Ringer solution were infused during phlebotomy and operation. The cardiovascular system remained stable and diuresis high. Postoperative complications were few and did not prolong hospitalization. The mean peroperative blood loss per patient was 680 ml. Fresh autotransfusion did not improve early postoperative anemia.
A 32-day-old male infant had hypocalcaemic convulsions associated with asymptomatic maternal hyperparathyroidism. Very low total and ionised serum calcium, increased serum phosphate, and normal serum parathyroid hormone (PTH) and 25-hydroxycholecalciferol (25-OHD3) concentrations were found at admission. After treatment with calcium and vitamin D, serum PTH and 25-OHD3 concentrations increased markedly before serum calcium levels returned to normal perhaps indicating an inability to convert 25-OHD3 to the metabolically active 1,25-dihyroxyvitamin D3 during the hyperphosphataemic state. Treatment with 1,25-dihdroxyvitamin D3 or its analogues is recommended.
Serial 99mTc-pyrophosphate (99mTcPP) uptake measurements were performed, during the healing period, in 12 patients with fracture of the distal end of the radius without displacement. A peak value in uptake ratio was seen within 4 weeks in all patients. For clinical reasons the patients were divided into a normal healing and a slow healing group. 99mTcPP uptake at 6 weeks after the fracture was significantly higher in the slow healing group. Quantitation of the healing process in forearm fractures is possible using 99mTcPP and a gamma camera, and concentrating on small selected areas of interest.
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