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Biomedical subjects

A Larsson

Publications and source records attributed to A Larsson.

At least 487 records · Page 27Linked to original sources
PubMed1979

Ketotic hypoglycemia of childhood--a clinical trial of several unifying etiological hypotheses.

We have studied 15 children referred to St. Göran's Children's Hospital because of suspected ketotic hypoglycemia. The patients were investigated according to a program designed to test several hypotheses--old and new--postulated to explain the etiology of ketotic hypoglycemia. We have used the classical ketogenic provocation with a low calorie, high fat diet and measured the blood levels of several substrates and hormones as well as the urinary excretion of certain metabolites and hormones. Out of the 15 children, 6 will fill the criteria of ketotic hypoglycemia at the time of study. The most remarkable finding in these 6 children in contrast to the other children studied was that they did not decrease their peripheral glucose utilization (measured as Kg) during starvation. These 6 children seemed to be more "advanced" in their adaptation to ketogenic diet in all other parameters studied. The children with ketotic hypoglycemia did not differ from the other children in plasma level of cortisol or urinary excretion of nitrogen, urea, 3-methylstidine and catecholamines. We favour the concept that the children with ketotic hypoglycemia represent the tail of the gaussian curve in the normal age-dependent development of the adaptation to starvation.

Alanine↗
PubMed1979

Potential inhibitors of rat tooth alkaline phosphatase studied by means of different histochemical techniques.

Two histochemical methods for demonstration of alkaline phosphatase activity, a lead pyrophosphate- anda naphtholphosphate technique, were compared. Since different results may be due to methodological differences as well as different enzyme activities, the enzymatic hydrolysis of the naphtholphosphate was visualized both by means of an azo-dye coupler and by lead-capturing of the liberated phosphate ion. Various potential inhibitors of alkaline phosphatase activity (diphosphonate, D-penicillamine, and sodium fluoride) were also tested. The use of diphosphonate and D-penicillamine resulted in inhibited or reduced staining, which could mainly be explained by an interference by these compounds with components in the incubation media rather than with the enzyme itself. The addition of sodium fluoride had no effect on the naphtholphosphate staining pattern irrespective of capturing method, whereas the odontoblastic pyrophosphate splitting alkaline phosphatase appeared to be sensitive to sodium fluoride, suggesting the presence of two alkaline phosphatases in odontoblasts.

Alkaline Phosphatase↗
PubMed1979

Studies of renal urea cycle enzymes. I. Renal concentrating ability and urea cycle enzymes in the rat during protein deprivation.

Activities of renal urea enzymes were studied in normally fed (21% dietary protein) rats and rats deprived of protein (6% dietary protein) for 3 weeks. Protein deprivation resulted in growth retardation and defective urine concentrating ability. Compared to rats on an optimal diet containing 21% of protein, the protein starved animals had decreased concentrations of protein and urea in serum, reduced urinary excretion of urea and decreased levels of all five urea cycle enzyme activities in the liver. In the kidney, however, protein malnutrition resulted in a significant increase in arginase specific activity from 11.5 +/- 1.1 to 16.3 +/- 1.5 (M +/- SD) whereas the other urea cycle enzymes remained unchanged. It is postulated that this increase in renal arginase might be an early compensatory mechanism to preserve a net synthesis of urea in a situation involving arginine deficiency, thereby preserving an intact hypertonic gradient in the renal medulla.

Animals↗
PubMed1978

Trisodium phosphonoformate, a new antiviral compound.

Trisodium phosphonoformate selectively inhibits cell-free DNA polymerase activity induced by herpesvirus. The new inhibitor has an antiviral effect on herpes simplex virus types 1 and 2, pseudorables virus, and infectious bovine rhinotracheitis virus in cell culture. It has a good therapeutic activity against cutaneous herpes simplex virus infection in guinea pigs.

Animals↗
PubMed1978

Glutathione and gamma-glutamylcysteine in whole blood, plasma and erythrocytes.

A method for the simultaneous determination of glutathione and gamma-glutamylcysteine in capillary blood samples is described. The whole blood levels of glutathione and gamma-glutamylcysteine are t.09 +/- 0.20 mmol/l and 25 +/- 8 mumol/l (M +/- S.D.), respectively. The plasma concentration is approximately 4 mumol/l for both compounds. It is important to treat the blood samples with a reducing agent before protein precipitation to release glutathione and gamma-glutamylcysteine from disulfide linkages since, otherwise, 30--40% of the glutathione and 80% of the gamma-glutamylcysteine is lost with the protein precipitate. Whole blood is preferable to washed erythrocytes for the analysis since the washing procedure involves losses of, especially, gamma-glutamylcysteine.

Adult↗
PubMed1978

In vitro interaction between 99Tcm-labeled pyrophosphate, 32P-labeled pyrophosphate and rat tissues.

Whole-body sections from young rats were incubated with solutions containing 32P-labeled pyrophosphate, 99Tcm-labeled pyrophosphate and 99Tcm-pertechnetate, respectively, at pH 7.6 or pH 8.6. After incubation, the sections were used for autoradiography and/or staining in order to visualize tissue affinity for 99 Tcm and areas of pyrophosphatase activity. At pH 7.6, the distribution patterns of 99Tcm-labeled pyrophosphate and 32P-labeled pyrophosphate were similar. When pH was raised to 8.6, 99Tcm-labeled pyrophosphate was degraded before reaching the tissues and their enzymes. The distribution pattern of 99Tcm-labeled pyrophosphate at pH 8.6 was similar to that of 99Tcm-pertechnetate. 32P-labeled pyrophosphate could serve as a substrate for alkaline pyrophosphatase and the enzyme activity was demonstrated autoradiographically.

Animals↗
PubMed1978

The effect of cadmium on the hematology and on the activity of delta-aminolevulinic acid dehydratase (ALA-D) in blood and hematopoietic tissues of the flounder, Pleuronectes flesus L.

Flounders (Pleuronectes flesus) were exposed to sublethal levels of cadmium (5, 50, and 500 micrograms of Cd2+/liter) for periods of 4 and 9 weeks, and the hematological response as well as the effect on the activity of delta-aminolevulinic acid dehydratase (ALA-D) in blood and blood-forming tissues were investigated. Significant reductions of hematocrit, hemoglobin, and red blood cell count were found in the cadmium-exposed fish. This anemic response was apparent even in flounders exposed to the lowest cadmium concentration, approximately corresponding to 1/4000 of the 96-hr LC50 value. The anemia was accompanied by a significant increase of the ALA-D activity in renal tissues. This indicates a compensatory stimulation of the introductory steps of the hemoglobin biosynthesis. However, the formation of hemoglobin does not seem to be accomplished, which might be due to a disturbed iron metabolism. The cadmium exposure also resulted in a significant increase of the number of lymphocytes, indicating an action on the immunological defense of the fish.

Animals↗
PubMed1978

Chronic sclerosing osteomyelitis of the mandible. Scintigraphic and radiographic findings.

Fourteen patients with chronic sclerosing osteomyelitis of the mandible were investigated with 99mTc-labeled bone-seeking agents. Scintigraphic findings were compared with radiographic features. High uptake of diphosphonate and polyphosphate was demonstrated in diseased areas. Good agreement was found between radiography and scintigraphy concerning the extent and activity of each process. The use of bone-seeking radiopharmaceuticals in other types of skeletal lesions and differential diagnostic aspects are discussed.

Adolescent↗
PubMed1978

Intraosseous neurofibroma of the jaws.

Two cases of intraosseous neurofibromas of the mandible are presented. Only 25 cases of this tumor have been published previously. Of the present two cases, one was located at the upper border of the mandible, in the left second molar area where the tooth had been extracted 2 years previously. In the second case, the tumor presented itself as a 10 x 2 cm large destruction, mainly following the course of the alveolar nerve from the mandibular foramen to the mental foramen in the right side of the jaw. The mandibular first right molar was missing but the relationship between the extraction of the tooth and the development of the tumor could not be demonstrated. Histologically, the two tumors differed in the way that case 1 showed a conspicuous amount of delicate, wavy fibrils, some of which showed concentric lamellations resembling the pacinian corpuscle but without neurites containing nerve fiber bundles and also demonstrated a slight pleomorphism.

Adult↗
PubMed1978

Specificity of Fc-receptors on lymphocytes and monocytes for guinea-pig IgG1 and IgG2: phagocytosis of erythrocytes.

The capacity of guinea-pig IgG1 and IgG2 antibodies to induce lymphocyte (K-cell) mediated lysis or monocyte/macrophage mediated phagocytosis of erythrocytes was studied with both human and guinea-pig effector cells. For both species, induction of K-cell mediated lysis was restricted to IgG2 whereas both IgG1 and IgG2 could induce monocyte/macrophage mediated phagocytosis. In competitive inhibition experiments, only complexed IgG2 inhibited lysis mediated by K-cells. The results suggest that the fc-receptors on K-cells only recognize IgG2. In contrast, complexes of both subclasses inhibited phagocytosis by human monocytes, regardless of the subclass of the inducing antibodies. Inhibition of guinea-pig macrophage mediated phagocytosis by IgG2 complexes was also independent of the inducing antibody. Hence, Fc-receptors common for IgG1 and IgG2 seem to be involved in themonocyte/macrophage mediated effector reaction. Free IgG1 was significantly less ingibitory than free IgG2 for human monocytes and hardly at all for guinea-pig macrophages. However, free IgG2, which was cytophilic for these cells, was more aggregated than IgG1. Thus, both molecular structure and state of aggregation determine interaction of IgG with cellular Fc-receptors.

Animals↗
PubMed1978

Congenital hypothyroidism in Sweden. Incidence and age at diagnosis.

A total number of 112 children with congenital hypothyroidism were diagnosed in all Children's Hospitals and Pediatric Wards in Sweden during the 7-year period 1969-1975. Since it may be assumed that all cases of congenital hypothyroidism, which were diagnosed during that period were seen in one of these hospitals, the incidence of congenital hypothyroidism in Sweden can be calculated to be 1:6900 live births. In spite of an efficient National Health Care Program for infants the diagnosis was delayed until after an age of three months in 52% of the cases. This fact supports the view that mass screening of newborns for congenital hypothyroidism has to be introduced in Sweden. However, the beneficial effects of such a program cannot be fully elucidated until it has been considered whether earlier instituted treatment would have improved the outcome of children in whom a diagnosis was made after 3 months of age.

Age Factors↗
PubMed1978

The effects of ethylene-1-hydroxy-1, 1-diphosphonate on cellular transformation and organic matrix of the epiphyseal growth plate of the rat--a light microscopic and ultrastructural study.

Ethylene-1-hydroxy-1, 1-diphosphonate (EHDP) was administered intraperitoneally to one-day-old rats. In the first experiment, each animal was given 4 injections of EHDP distributed over two consecutive days and corresponding to a total amount of EHDP of 100 mg/kg bwt/day. The animals were sacrificed 12 hours after the last injection. In the second experiment, each animal was given 3 injections, each containing 50 mg of EHDP/kg bwt, with an interval of 6 hours and were thereafter left to survive for 4 days. Animals in the first experiment showed in comparison to normal controls an increased width of the hypertrophic zone; lack of calcified septa within the zone of provisional calcification; persistent atypical chondrocytes in the calcification zone and a large number of matrix vesicles lacking in crystals. The ground substance showed an accumulation of fine precipitates apparently representing undegraded aggregates of proteoglycan macromolecules. Animals in the second experiment formed a new apparently normal epiphyseal growth plate, while the "old" epiphyseal cartilage formed under the influence of EHDP remained largely unresorbed within the metaphysis. Besides the previously described inhibitory effects of diphosphonates on the crystallization of matrix vesicles and the growth of hydroxyapatite crystals, EHDP, at the doses used, was found to have a profound inhibitory effect on the differentiation and migration of the epiphyseal chondrocytes as well as on the degradation of proteoglycan macromolecules. The observed inhibition of vascular invasion appears to be related to inhibition of enzyme degradation of the ground substance, as evidenced by the observation of extracellular lysosomelike bodies in the erosion zone.

Animals↗
PubMed1978

Reversible inhibition of cellular metabolism by ribavirin.

The broad spectrum antiviral drug ribavirin (Virazole, 1-beta-d-ribofuranosyl-1,2,4-triazole-3-carboxamide) inhibits cellular macromolecular synthesis as well as cell division in eucaryotic cells. The concentration and time dependence have been studied. One-hour treatment with 25 muM ribavirin or 18 h with 2 muM inhibited the deoxyribonucleic acid synthesis to 50%. Higher concentrations of ribavirin were required to obtain a similar inhibition of ribonucleic acid and protein synthesis. This effect on cell metabolism and cell division can be reversed by removing the drug from the cells.

Cell Division↗