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Biomedical subjects

H Rasmussen

Publications and source records attributed to H Rasmussen.

At least 235 records · Page 13Linked to original sources
PubMed1980

Effect of dietary phosphate on transport properties of pig renal microvillus vesicles.

Dietary phosphate manipulation results in stable adaptive changes in the transport functions of microvillus membrane vesicles isolated from pig renal cortex. When assayed under sodium gradient conditions, phosphate uptake is enhanced 200--400% in vesicles prepared from animals maintained on a low-phosphate diet (0.22%) compared to high-phosphate diet controls (0.82%). When transport is assayed in sodium preequilibrated vesicles, a 100% enhancement of phosphate uptake is demonstrable. Stimulation of phosphate uptake into low-phosphate diet vesicles after the imposition of a sodium chloride gradient is equivalent if uptake is measured at pH 6.0 or 8.0 and can be kinetically characterized as resulting from a Vmax alteration in the phosphate transport system. Microvillus membrane vesicle phosphate transport is maximally stimulated after only 2 days of dietary deprivation. Although a longer period (1 and 2 wk) of phosphate restriction does not further stimulate phosphate transport, it does result in an inhibtion of other sodium gradient-dependent transport systems (glucose, alanine).

Animals↗
PubMed1980

Determinants of hypoventilation during wakefulness and sleep in diaphragmatic paralysis.

A 45-yr-old man with limb girdle muscular dystrophy, bilateral diaphragmatic paralysis, chronic carbon dioxide retention, and hypersomnolence was studied to determine the causes of hypoventilation during wakefulness and during sleep. Awake hypoventilation was associated with an insufficient inspiratory effort in the presence of inefficient respiratory muscles and a shortened inspiratory time. During sleep, severe hypoventilation and oxygen desaturation occurred only during REM-induced intercostal and accessory muscle inhibition.

Diaphragm↗
PubMed1980

Assessment of bone mass in the radius by computed tomography.

A reproducible method for quantitative analysis of computed tomographic cross-sections of the distal radius of patients with various metabolic bone diseases is described. A statistically significant correlation between the CT measurements in the radius and quantitative histomorphometric measurement of the trabecular bone volume of corresponding transilial bone biopsies is demonstrated. Selected longitudinal studies are presented to demonstrate the possible clinical applications of this type of CT analysis.

Adult↗
PubMed1980

Definition of the pathway for membrane phospholipid fatty acid turnover in human erythrocytes.

Techniques have been developed to permit detection of acyl thioesters derived from exogenous fatty acids in erythrocytes. These acyl thioesters have been shown to act as intermediates in the acylation of endogenous lysophospholipid. Release of fatty acids from erythrocyte phospholipids has also been detected. Such release reflect the activity of an endogenous phospholipase that utilizes endogenous phospholipid as substrate. These observations permit further definition of the biochemical pathway for erythrocyte phospholipid fatty acid turnover.

Chemical Phenomena↗
PubMed1980

Situs inversus of the descending colon and sigmoid.

A case is described where the descending colon and the sigmoid were sited totally in the right side of the abdomen, verified radiologically and in connection with an operation for perforated tumour of the colon.

Aged↗
PubMed1979

Isolation of specific bone cell types by free-flow electrophoresis.

The bone cells and fibroblasts from fetal rat calvaria can be isolated by collagenase digestion of the collagen matrix and separated into specific cell types by free-flow electrophoresis. The method involves injection of a specially prepared suspension of cells into a stream of buffer across which is maintained an electric field of 60 V/cm. The fetal bone cell types are differentially deflected toward the anode where they can be collected. Free-flow electrophoresis of this heterogenous cell preparation yields three distinguishable peaks which can be identified by morphologic, morphometric, and enzymatic characteristics. All three cell peaks have greater than 95% viability as judged by trypan blue exclusion and will grow to confluent monolayers in culture. The data indicate that these cell peaks may be comprised of osteoclasts and/or preosteoclasts, osteoblasts and/or preosteoblasts, and fibroblasts.

Acetazolamide↗
PubMed1979

Parathyroid function and vitamin D metabolism during human growth hormone replacement.

Changes in calcium and phosphorus metabolism were studied in nine children with GH deficiency before and during human GH replacement therapy. Parathyroid function and serum concentrations of physiologically important vitamin D metabolites were examined to determine their relationship to changes in mineral metabolism. By comparison with pretreatment values, the GH-treated children showed significant increases in growth rate and renal tubular phosphate reabsorption and a significant decrease in urinary calcium excretion after a standardized oral load. There was no significant change in serum concentrations of parathyroid hormone, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, or 24,25-dihydroxyvitamin D or in nephrogenous cAMP excretion. Although GH has been proposed as a regulator of vitamin D metabolism, the present study demonstrates that the anabolic changes in calcium and phosphorus metabolism accompanying GH therapy are not mediated via changes in parathyroid hormone or vitamin D status.

Adolescent↗
PubMed1978

Purification and characterization of chick intestine brush border membrane. Effects of 1alpha(OH) vitamin D3 treatment.

A new technique has been developed for the isolation of membrane vesicles from the vitamin D-deficient and vitamin D-treated chick intestinal brush border membrane. The technique involves removal of nuclei from a low speed pellet by discontinuous sucrose gradient centrifugation. The resulting intact brush borders are then homogenized in 0.5 M Tris and the membrane fragments purified on a glycerol gradient. This preparation represents a 20-fold purification of the brush border marker sucrase. After 1alpha-hydroxyvitamin D3 treatment there is a significant increase in membrane phospholipid phosphorous, an alteration in the fatty acid composition of the phosphatidylcholine fraction of membrane phospholipid, and a decrease in sucrase specific activity.

Animals↗
PubMed1978

Ionic and metabolic requirements for the hydroosmotic response to antidiuretic hormone in toad urinary bladder.

A study has been conducted to determine the ionic and metabolic requirements for full expression of the hydroosmotic response to antidiuretic hormone in the toad urinary bladder. By appropriate manipulation of incubation conditions it can be shown that there is a pool of serosal sodium necessary for a full hormone response. This serosal sodium pool is not related to the transepithelial sodium transport pool A full hydroosmotic response also requires serosal potassium; however, no specific anion requirement was demonstrated. Additionally, anaerobic or aerobic metabolism support a full hydroosmotic response equally well.

Animals↗