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Biomedical subjects

I Holmberg

Publications and source records attributed to I Holmberg.

At least 37 records · Page 2Linked to original sources
PubMed1982

Survival of female geriatric patients after hip fracture surgery. A comparison of 5 anesthetic methods.

Female geriatric patients (mean age 80.9 years; n = 169) undergoing surgery for hip fracture were given epidural, neurolept analgesia, ketamine, enflurane or halothane anesthesia. The rate of survival in the different groups was studied up to 4 years after the operation and compared with the expected survival of normal groups of women with the same age distribution. Mortality at 1 month (6.5%) was equally distributed between the anesthetic methods and was not correlated to age or the type of fracture. The preoperative condition of the patient seemed to be the most important factor for survival. At 6 months, the rate of mortality was 17.2%. Together with age, the type of fracture was the most important determinant for survival. Differences in late survival between the groups were recorded, but the clinical significance of these differences is uncertain since many factors other than the anesthetic method may be more important.

Aged↗
PubMed1982

Relation between hypercalciuria and vitamin D3-status in patients with urolithiasis.

Patients with urolithiasis were divided into two groups, one (n = 38) with a urinary excretion of calcium exceeding 6.0 mmol/24 h and one (n = 32) with a calcium excretion lower than 6.1 mmol/24 h. The group of patients with a high urinary excretion of calcium had a significantly higher level of 25-hydroxy vitamin D3 (26.2 +/- 1.6 ng/ml) than had the group of patients with a normal urinary excretion of calcium (17.6 +/- 0.9 ng/ml) (p less than 0.001). A highly specific and accurate method, based on isotope dilution--mass spectrometry was used in the assay of 25-hydroxy vitamin D3. There was no over-all correlation between level of 25-hydroxy vitamin D3 and serum level of calcium (r = 0.1). The results are in accordance with the contention that the vitamin D3-status might be of some importance for the development of hypercalciuria in these patients.

Adolescent↗
PubMed1981

Uptake and 25-hydroxylation of vitamin D3 by isolated rat liver cells.

The physiological roles played by hepatocytes and nonparenchymal cells of rat liver in the metabolism of vitamin D3 have been investigated. Tritium-labeled vitamin D3 dissolved in ethanol was administered intravenously to two rats. Isolation of the liver cells 30 and 70 min after the injection showed that vitamin D3 had been taken up both by the hepatocytes and by the nonparenchymal liver cells. The relative proportion of vitamin D3 that accumulated in the nonparenchymal cells increased with time. Perfusion of the isolated rat liver with [3H] vitamin D3 added to the perfusate confirmed the ability of both cell types to efficiently take up vitamin D3 from the circulation. By a method based on high pressure liquid chromatography and isotope dilution-mass fragmentography it was found that isolated liver cells in suspension had a considerable capacity to take up vitamin D3 from the medium. About 2.5 fmol of vitamin D3 were found to be associated with each hepatocyte or nonparenchymal cell after 1 h of incubation. 25-Hydroxylation in vitro was found to be carried out only by the hepatocytes. The rate of hydroxylation was about the same whether the cells were isolated from normal or rachitic rats (3.5 and 4 pmol of 25-hydroxyvitamin D3 formed per h per 10(6) cells, respectively). The possibility that the nonparenchymal cells might serve as a storage site for vitamin D3 in the liver is discussed.

Animals↗
PubMed1979

Assay of 1,25-dihydroxy vitamin D3 by isotope dilution--mass fragmentography.

We describe a specific assay of 1,25-dihydroxy vitamin D3 in human serum, based on isotope dilution-mass fragmentography. We added [26-2H3]-1,25-dihydroxy vitamin D3 to a fixed amount of serum. The steroids were extracted with chloroform/methanol and purified by liquid chromatography. The purified materal was converted into the trimethylsilyl ether and analyzed. Unlabeled 1,25-dihydroxy vitamin D3 was quantitated from the ratio between the tracings at m/e 452 and 455. The two ions used correspond to loss of two trimethylsilyloxo functions from the molecular ion. Essentially the same results, with some problems of interference, were obtained when we used the more intense ions at m/e 131 and 134 (corresponding to cleavage between C-24 and C-25). The detection limit was about 5 ng/L of serum; the coefficient of variation was about 6%. The accuracy of the method was assessed by recovery experiments. 1,25-Dihydroxy vitamin D3 in sera from 15 healthy subjects was found to average 55 +/- 10 ng/L(+/- SD). We believe this represents the first determination of 1,25-dihydroxy vitamin D3 in serum by use of a method not based on radioimmunoassay or receptor assay. Slightly lower values have been reported by those latter techniques.

Chromatography, High Pressure Liquid↗
PubMed1976

A novel specific assay of 25-hydroxy vitamin D.

The synthesis of 25-hydroxy-[26-2H3]vitamin D3 is described. A fixed amount of this compound (usually 250 ng) is added to a fixed amount of serum (usually 2.5 ml) and the mixture is extracted with a chloroform/methanol mixture. The extract is chromatographed on a Sephadex LH-20 column together with a trace amount of 25-hydroxy-[263H3]vitamin D3. The chromatographic fraction corresponding to 25-hydroxy vitamin D3 is converted into trimethylsilyl ether and the amount of unlabeled 25hydroxy vitamin D3 is determined from the ratio between the mass fragmentographic recording at m/e 131 (base peak of unlabeled 25-hydroxy vitamin D3) and m/e 134 (base peak 25-hydroxy-[26-2H3]vitamin D3). The relative standard deviation of the method was about 5%.

Chromatography, Gel↗