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Biomedical subjects

R Ekman

Publications and source records attributed to R Ekman.

At least 271 records · Page 15Linked to original sources
PubMed1983

Neuropeptides in the thyroid gland: distribution of substance P and gastrin/cholecystokinin and their effects on the secretion of iodothyronine and calcitonin.

Previously, vasoactive intestinal polypeptide was localized to intrathyroidal nerve fibers. It stimulates iodothyronine secretion in mice. In the present study two populations of nerve fibers containing substance P and gastrin/cholecystokinin (CCK)-like immunoreactivity, respectively, were demonstrated in the thyroid gland of several mammals. The substance P fibers occurred around blood vessels and follicles, whereas the gastrin/CCK fibers occurred mainly around follicles. In the chicken thyroid and ultimobranchial glands only substance P-containing fibers could be demonstrated. Such fibers were particularly numerous in the ultimobranchial gland. CCK-4, CCK-8, and substance P did not increase thyronine secretion measured as release of radioiodine into the circulation of mice pretreated with Na125I and T4. The TSH-induced release of radioiodine was also unaffected. Calcitonin secretion in rats was stimulated by CCK-4, CCK-8, substance P, and vasoactive intestinal polypeptide.

Animals↗
PubMed1982

Radioimmunoassay of pro-gamma-melanotropin, the amino-terminal fragment of proopiolipomelanocortin.

A RIA has been developed for natural porcine pro-gamma MSH, the 103-amino acid peptide that represents the amino-terminal part of proopiolipomelanocortin. Rabbits were immunized with the purified peptide polymerized with glutaraldehyde. The antiserum is directed against the amino-terminal end of the antigen and does not cross-react with corticotropin, beta-lipotropin, beta-endorphin, gamma 3MSH, or gamma 2MSH. The minimum detectable concentration is 0.15 ng/ml standard pro-gamma MSH (15 pg/tube). Pro-gamma MSH-like immunoreactivity was detected in plasma and extracts of the hypothalamus and pituitary of pigs. Gel chromatography of these extracts revealed at least three immunoreactive peaks in the anterior and neurointermediate lobes of the pituitary, whereas two immunoreactive peaks were found in extracts of the hypothalamus.

Amino Acid Sequence↗
PubMed1981

Evidence for the presence of pro-gamma-melanotropin, the NH2-terminal fragment of the corticotropin-beta-lipotropin precursor, in corticotropin-producing tumours.

Five corticotropin-producing tumours were examined for peptides related to the corticotropin-beta-lipotropin precursor. Two were basophil pituitary adenomas and three were bronchial carcinoids. The cells of the two pituitary adenomas stained with antisera against beta-endorphin and against pro-gamma-melanotropin, the NH2-terminal fragment of the corticotropin-beta-lipotropin precursor, but not with antisera against alpha-melanotropin or beta-lipotropin. The corticotropin-storing tumor cells of the bronchial carcinoids stained with antisera against beta-endorphin, beta-lipotropin or pro-gamma-melanotropin. Only one of the three bronchial carcinoids contained cells reacting with the antiserum against alpha-melanotropin. Although the two types of corticotropin-storing tumours (pituitary adenoma and bronchial carcinoid) differed with respect to beta-lipotropin content, the over-all picture indicates that the proteolytic processing of the corticotropin precursor proceeds along similar lines in tumour cells and in pituitary corticotrophs. An acetic acid extract of one of the bronchial tumours was subjected to gel chromatography and immunochemical analysis of material related to pro-gamma-melanotropin. The immunoreactive material displayed a considerable size heterogeneity, with the predominant components having a molecular weight larger than that of authentic pro-gamma-melanotropin.

Adenoma, Basophil↗
PubMed1980

High content of tyrosine and arginine in peptides and proteins from the growth hormone producing cells of the adenohypophysis.

Fluorescence histochemistry has demonstrated an abundance of tyrosine and arginine residues in the growth hormone (GH) producing cells of the pituitary of several mammals. Granules from pig pituitaries were purified by passage through a succession of Millipore filters followed by centrifugation on a continuous sucrose gradient. One granular fraction, rich in GH, was found to contain proteins or peptides rich in tyrosine and arginine. Gel chromatography of the acid-soluble components from sedimented pituitary granules revealed that the arginine- and tyrosine-rich material was heterogeneous. The arginine-containing peptides and proteins could be separated into several peaks with molecular weights from 5000-10,000 and higher. The tyrosine-containing material comprised one peptide with a molecular weight of 5000-10,000 and another much smaller peptide. Since GH itself is not excessively rich in either tyrosine or arginine, the tyrosine- and arginine-containing proteins or peptides probably constitute as yet unidentified granular components, distinct from GH itself.

Animals↗
PubMed1979

Medicinal iron to low birth weight infants.

Serum ferritin concentrations were measured during the first 6 months of life in 28 low birth weight infants (mean birth weight 1820 g range 900-2460; mean gestational age 34 weeks range 29-37) fed a standard formula fortified with ferrous sulphate. Fifteen of the infants received supplementary medicinal iron (ferrous succinate) from 3 weeks of age, and 13 only from 2 months of age. All were given vitamin E from 10 days of age. The serum ferritin values did not differ between the groups at 1-2 days, 8-10 weeks or at 6 months. Furthermore, there were no signs of hyperhaemolysis at 8-10 weeks in the group receiving medicinal iron early. The data indicate that the iron content in the formula is sufficient until 2 months of age, but also that thereis no disadvantage in starting medicinal iron at 3 weeks of age, if the diet is sufficient in vitamin E.

Breast Feeding↗
PubMed1979

Variation of serum ferritin in low birth weight infants with maternal ferritin, birth weight and gestational age.

Serum ferritin measured at birth in 69 low birth weight infants proved to vary with gestational age as well as with weight. The increase with gestational age was even more striking when the infants small for gestational age were excluded. The relation between maternal and infant serum ferritin concentration was investigated for 2 groups of infants and their mothers (*preterm and term infants, respectively). Neither in preterm nor in term infants was the serum ferritin found to vary with that in the respective mothers.

Birth Weight↗
PubMed1979

The effect of short-term high-dose treatment with methenamine hippurate of urinary infection in geriatric patients with indwelling catheters. II. Evaluation by means of a quantified urine sediment.

The urine sediment of 12 geriatric patients with indwelling catheters was quantified by the glutaraldehyde-cytocentrifuge method prior to, during and after a clinical trial of methenamine hippurate (MH), 2 g x 3 daily given for 34 days as the sole therapeutic agent for the urinary tract infection. The median leukocyte concentration in the urine of these patients was 100 cells/microliter (Q1 - Q3 50-350), i.e. tenfold higher than the upper normal limits reported in healthy probands. The median bacteriuria in the control period was 12 x 10(5) bacteria/ml urine, interquartile range 10-60 x 10(5) bacteria/ml and extreme individual values 300-500 x 10(5) bacteria/ml. Hematuria, defined as greater than or equal to 24 erythrocytes/microliter urine, was not prominent and could not be correlated with MH treatment, nor with catheter changes. The reported observations suggest that short-term high-dose treatment with MH as sole therapeutic agent reduced pyruria and bacteriuria in the group of patients studied.

Aged↗
PubMed1978

Plasma lipoprotein separations by zonal ultracentrifugation.

Procedures for the separation of plasma lipoprotein classes and subclasses by zonal ultracentrifugation are described. The main density classes, very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL), in plasma can be separated in a single run for 20 hours. For the isolation of VLDL-LDL a centrifugation time of only 90 minutes is needed. Separations can be performed on plasma volumes varying from 10 to 400 ml in the Ti-14 rotor used; VLDL can in this way be isolated from 400 ml plasma in 30 minutes. The advantages and disadvantages of zonal ultracentrifugation in comparison with the commonly employed differential ultracentrifugation for separation of lipoproteins are discussed.

Centrifugation, Zonal↗
PubMed1978

Changes in plasma high density lipoproteins in chronic male alcoholics during and after abuse.

Alterations in plasma high density lipoproteins (HDL) were studied in thirty-eight male chronic alcoholics. Twenty-four (63%) of the patients had increased HDL protein (measured immunochemically) and twenty-five (66%) had increased HDL cholesterol (determined after polyanion precipitation of very low density lipoproteins (VLDL) and low density lipoproteins (LDL)). A statistically significant correlation was found between HDL protein and HDL cholesterol (r = 0.39). gamma-Glutamyltransferase (GT) was elevated in eighteen (47%) of the alcoholics. No significant correlations were found between GT and HDL protein or HDL cholesterol. The increase in HDL, as studied by rate zonal ultracentrifugation, was heterogeneous with changes in the HDL2 as well as HDL3 subfractions. It is suggested that determination of HDL total cholesterol, in combination with GT, may represent a valuable and sensitive test for detection of alcoholism.

Adult↗