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Biomedical subjects

E Christensen

Publications and source records attributed to E Christensen.

At least 217 records · Page 12Linked to original sources
PubMed1982

Metabolic events in infants of diabetic mothers during first 24 hours after birth. III. Changes in plasma amino acids.

Plasma amino acid concentration (AAC) were studied in 31 diabetic mothers (10 of White class A, 10 of B-C and 11 of D-F) and their 32 infants during the first 24 hours after birth. Only minor differences between the 3 groups were found at birth and 2 hours, and none at 12 and 24 hours after birth. The individual AAC in umbilical vein plasma did not correlate with birthweight. All AAC except aspartic acid, asparagine, cystine and glutamic acid were higher in umbilical venous plasma than in maternal plasma. Umbilical venous-arterial differences of amino acids did not correlate with maternal or umbilical vein insulin concentrations except for threonine and valine. In general essential amino acids decreased after birth. In 8 infants with hypoglycemia and hyperinsulinism at 2 hours of age several plasma amino acids were lower than in the normoglycemic infants.

Adult↗
PubMed1982

Studies on pyruvate carboxylase, pyruvate decarboxylase and lipoamide dehydrogenase in subacute necrotizing encephalomyelopathy.

In two autopsy-proven cases of subacute necrotizing encephalomyelopathy (SNE, Leigh's Disease) the activities of pyruvate carboxylase, pyruvate decarboxylase and lipoamide dehydrogenase were investigated in cultured fibroblasts. Normal activities of pyruvate carboxylase and lipoamide dehydrogenase were found in both cases. The activity of pyruvate decarboxylase was low in one of the cases (p less than 0.05), while the activity in the other was within normal limits. The concentrations of alanine, lactate and pyruvate were normal or only slightly increased. The relationship between SNE and a defect in pyruvate metabolism is under discussion, and it is concluded that the general assumption that pyruvate carboxylase deficiency is the cause of SNE is not in agreement with our results or the present literature. However, pyruvate decarboxylase deficiency may in some cases contribute to the development of SNE.

Alanine↗
PubMed1982

Acclimatization to dry heat: active men vs. active women.

Physiological responses to exercise in dry heat were compared between six active men [maximum O2 consumption (VO2max), 51.4 +/- 1.2 ml . kg-1 . min-1] and four active women (VO2max, 47.2 +/- 1.3 ml . kg-1 . min-1) before, during, and after heat acclimatization. Subjects cycled a maximum of 2 h at 40% VO2max at 45 degrees C dry-bulb temperature, 23 degrees C wet-bulb temperature for 11 days. Prior to acclimatization there were no sexual differences for performance time, rate of increase of rectal temperature (delta Tre), or sweat rate per degree C increase of rectal temperature (msw/delta Tre). Sweat rate (msw) was greater for the men than for the women. Although there was no difference in the rate of increase of heart rate (delta HR), HR for the women was maintained 15-20 beats . min-1 higher than for the men. Acclimatization occurred for both sexes as indicated by reduced Tre and HR and increased msw and performance time. With acclimatization the women had longer performance times than the men. Even though the men still had greater msw, delta Tre was also greater; therefore msw/delta Tre for the men was less than for the women. Neither HR nor delta HR was different between the sexes. Throughout, resting hematocrit for the women was less than for the men; no changes in hematocrit were observed during exercise or with acclimatization. Plasma protein concentration increased during exercise on all days; no changes in plasma osmolality were observed. It is concluded that active women perform exercise of equal relative intensity in dry heat as well as active men. Moreover active women acclimatized to heat at a faster rate or to a greater extent than did active men.

Acclimatization↗
PubMed1982

Prenatal cytodifferentiation in the pars distalis of the dwarf mutant mouse.

The pars distalis of the pituitary gland was studied by means of electron microscopy in 14- to 18-day dwarf embryos (dw/dw) obtained from matings of dwarf homozygotes in which reproductivity was induced by hormone supplementation and pituitary transplants to the renal capsule. At 14 days of gestation the dwarf pars distalis shows fewer granulated cells than in the normal. Although somatotroph-like and mammotroph-like cells are identifiable in the normal pars distalis as early as 15 days, comparable cells are not present in the dwarf. By 17 and 18 days, the dwarf exhibits an ambiguous cell-type with a combination of somatotroph and mammotroph characteristics. At 18 days the dwarf also continues to show numerous nongranulated cells with large aggregates of glycogen, whereas in the normal pars distalis comparable glycogen-containing cells are relatively scarce.

Animals↗
PubMed1981

Urinary excretion of succinylacetone and delta-aminolevulinic acid in patients with hereditary tyrosinemia.

Succinylacetone was excreted in the urine from four patients, with hereditary tyrosinemia i.e., two patients with the severe infantile type with fatal outcome and two patients with less severe juvenile form. In the urine from two patients with neonatal transient tyrosinemia and from normal individuals succinylacetone was not detectable. The urinary excretion of delta-aminolevulinic acid was also increased in all patients with hereditary tyrosinemia compared to patients with neonatal transient tyrosinemia and to normal individuals. The results presented support the hypothesis of a deficiency of fumarylacetoacetase in hereditary tyrosinemia. Furthermore an analytical method for the quantitative determination of succinylacetone in urine using GC-MS is described.

Acetoacetates↗
PubMed1981

Formiminoglutamic aciduria in a slightly retarded boy with chronic obstructive lung disease.

A 2-year-old boy excreted massive amounts of formiminoglutamic acid in urine. The substance was identified as authentic formiminoglutamic acid by two-dimensional thin-layer chromatography, column chromatography and enzymatic determination. After alkaline hydrolysis the substance was converted to glutamic acid. Serum amino acid concentrations were normal. The patient had normal serum and erythrocyte folate levels. The red blood cell picture was normal. The leukocytes showed slight hypersegmentation. From the age of 3 months he exhibited recurrent otitis media and severe pulmonary infections. He had a peculiar narrow-headed look and marked universal hypotonia. The mental development was slightly retarded. Glutamate formiminotransferase deficiency is postulated. The findings lend support to the theory of glutamate formiminotransferase deficiency being a rather benign disorder of metabolism.

Child, Preschool↗
PubMed1981

Fine structure of somatotrophs and mammotrophs in the pituitary pars distalis of the little (lit) mutant mouse.

The cellular pathology and postnatal differentiation of somatotrophs and mammotrophs in the pars distalis of little (lit/lit) and normal (+/+; lit/+) mice were studied by means of electron microscopy. The results indicate that in little the pituitary at birth contains recognizable somatotrophs and mammotrophs; however, between 14 and 24 days of age a contrast between little and normal becomes conspicuous with respect to the somatotrophs. Little somatotrophs are less heavily populated with granules, have granules of smaller size, and show less developed organelles than do normal somatotrophs at comparable stages. Beyond 24 days the little somatotrophs become more difficult to locate, and those that do occur show a minimal increase in complexity from that present at 14 days. In contrast, the mammotrophs in little are similar in appearance to normal mammotrophs and show increasing complexity as development proceeds, often sending forth cellular processes between neighboring cells, as do normal mammotrophs.

Animals↗
PubMed1981

Clinical relevance of restrictive morphological criteria for the diagnosis of cirrhosis in liver biopsies.

Material obtained by needle biopsy of the liver from 532 patients with cirrhosis who had previously been examined has been re-evaluated using new and more restrictive histological criteria for the diagnosis of cirrhosis. The material was divided into four main groups: (A) cirrhosis, 287 biopsies; (B) probably cirrhosis, 101 biopsies; (C) compatible with but not diagnostic for cirrhosis, 89 biopsies; and (D) probably not cirrhosis, 11 biopsies. Group E consisted of 44 cases where no or insufficient material was available. The survival curves of the groups were significantly (P less than 0.05) different, with group D having the best survival followed by C, B and A. Clinical and laboratory manifestations of cirrhosis (more than five spider naevi, presence of ascites, daily alcohol intake of more than 50 g) were found significantly (P less than 0.05) more often among patients from group A, followed by patients from groups B, C and D. It is concluded that the more restrictive histological criteria for the diagnosis of cirrhosis in liver biopsies have clinical relevance, due to the prognostic and therapeutic implications of the diagnosis. The study also underlines the importance of specifying the criteria used when studies of patients with cirrhosis are reported.

Biopsy↗
PubMed1981

Aspects of the natural history of gastrointestinal bleeding in cirrhosis and the effect of prednisone.

The natural history of gastrointestinal bleeding in cirrhosis has been studied using prospectively collected data of 532 patients included in a randomized clinical trial with a regular follow-up of up to 12 yr. Of the total 199 patients who experienced gastrointestinal bleeding, 95 (48%) bled from esophageal or gastric varices, 67 (34%) bled from peptic ulcer or gastritis, and 37 (18%) had either insufficient evidence of the source (33) or mixed sources (4). In the total group of patients the cumulative percentage of patients in whom varices had been demonstrated of patients in whom varices had been demonstrated by radiography increased from 12 to 90 in 10 yr, while that of bleeding from varices increased from 7 to 40. In 104 patients who bled for the first time during the trial period (trial bleeding patients) the median number of bleeding episodes was one (range 1-8). In these patients the fatality from bleeding from varices was 82%. The risk of rebleeding from varices was 81%, and 4 yr after the first bleeding the cumulative survival had decreased to less than 10%. Rebleeding was significantly less frequent and survival significantly higher in patients bleeding from sources other than varices. Prednisone reduced the occurrence rate of varices, bleeding from varices, and death from bleeding varices in nonalcoholic females without ascites, 40% of whom fulfilled the histologic criteria of chronic active hepatitis. Prednisone significantly increased the occurrence rate of varices inpatient with ascites and of bleeding from varices in alcoholic patients. Prednisone significantly increased the occurrence rate of peptic ulcer in males and in patients without chronic active hepatitis.

Clinical Trials as Topic↗
PubMed1981

Fine structure of somatotrophs and mammotrophs during development of the dwarf (dw) mutant mouse.

The differentiation of somatotrophs and mammotrophs in the pars distalis of dwarf (dw/dw) and normal (+/+; dw/+) litter mates was studied by means of electron microscopy from the day of birth to 24 days, as well as in adults at 3-4 months of age. On the basis of a combination of growth measurements, including weight, total body length, and tail length, dwarfs were identifiable with certainty as early as 5 days in litters from heterozygous matings (dw/+ x dw/+). Newborn dwarfs were obtained from homozygous matings (dw/dw x dw/dw) of adult dwarfs which had been brought to sexual maturity by hormone supplementation. The results indicate that the dwarf pituitary is already abnormal at birth. In contrast to the pars distalis in the normal newborn mouse, somatotrophs and mammotrophs cannot be distinguished from one another nor can they be distinguished as a group from other cell types in the dwarf. However, as development progresses, the dwarfs show a large population of an ambiguous somatotroph-mammotroph-like cell with fine structural characteristics of both somatotrophs and mammotrophs; these ambiguous cells also occur in the 3-4 months old adult.

Aging↗
PubMed1980

Postnatal development of somatotrophs and mammotrophs in the pars distalis of the C57BL mouse.

The pars distalis of the pituitary gland of the C57BL mouse was studied by means of electron microscopy during postnatal stages of males ranging in age from newborn through 24 days, with particular emphasis on the somatotrophs and mammotrophs. During this period, growth curves were plotted in order to correlate postnatal growth patterns with the state of differentiation of the somatotrophs in the pars distalis. In the newborn, the somatotrophs show well developed organelles, including rough endoplasmic reticulum and Golgi complexes. These cells are not as densely packed with granules as the adult somatotrophs; however, from days 5 through 24, they show a progressive accumulation of granules. Although mammotrophs are scarce in the newborn, they are readily distinguishable in the pars distalis at 5 days. Male mice in small litters show a progressive increase in body weight between birth and 11-12 days, at which time the rate slackens until 18-19 days when the rate again increases. Growth curves for mice from large litters are similar to those from smaller litters, except that the transitory decrease in rate is more prominent.

Animals↗
PubMed1980

Studies on pyruvate carboxylase from cultured human fibroblasts and amniotic fluid cells.

The properties of pyruvate carboxylase in cultured human fibroblasts were investigated. A pH optimum around pH 7.6 was found in Tris buffer at 37 degrees C. The apparent Km for pyruvate and bicarbonate were 0.22 mmol/l and 2.1 mmol/l respectively. The activity of the crude homogenate was most stable at room temperature. The major end product was identified as citric acid during the assay conditions used. During growth the specific activity increased from 0.5 to 2 nmol/min per mg protein. The activity of pyruvate carboxylase in the crude homogenate from cultured human fibroblasts was 0.76 +/- 0.12 nmol/min per mg protein, while the activity in cultured amniotic fluid cells was 0.66 +/- 0.17 nmol/min per mg protein, suggesting the possibility of prenatal diagnosis of pyruvate carboxylase deficiency.

Amniotic Fluid↗
PubMed1980

Excretion pattern of branched-chain amino acid metabolites during the course of acute infections in a patient with methylmalonic acidaemia.

A 1-year-old boy with a typical B12-responsive form of methylmalonic acidaemia was hospitalized twice due to acute bacterial infections. On both occasions, the child was lethargic with a severe ketoacidosis on admission. Intensive therapy with protein restriction, intravenous administration of electrolytes and antibiotics was effective within 4 days on both occasions. The urinary excretion of organic acids showed the same pattern on both occasions. There were rising excretion concentrations, reaching a peak value within the first 24-hour period, for the following compounds: 3-hydroxybutyric acid, 3-hydroxypropionic acid, 3-hydroxyisobutyric acid and 3-hydroxyisovaleric acid. Excretion concentrations of the following rose for 48 h: isobutyric acid, 2-methylbutyric acid, isovaleric acid, lactic acid and the 2-oxo-acids. There was no increase until 12-24 h after the onset of severe illness in the excretion of propionic acid and methylmalonic acid. Propionic acid excretion was maximal at about 48 h, while peak excretion of methylmalonic acid was delayed until about 72 h after the onset of severe illness; at this time there was clinical improvement. The biochemical implications of this excretion pattern are discussed.

Acute Disease↗
PubMed1980

Biochemical studies in a patient with defects in the metabolism of acyl-CoA and sarcosine: another possible case of glutaric aciduria type II.

The clinical and biochemical abnormalities in a neonate, who died in coma accompanied by severe hypoglycaemia at the age of 3 days, are described. The study of the urinary metabolic profiles of organic acids and amino acids revealed that the excretion rates of glutaric acid, isovaleric acid, isovalerylglycine, 3-hydroxyisovaleric acid and isobutyric acid were very high. Increased excretion rates were also found for 2-methylbutyric acid, adipic acid, caproylglycine, 5-hydroxycaproic acid, caproic acid and butyric acid. The amino acid, sarcosine, was excreted in enhanced amounts and the patient had lactic aciduria, whereas the excretion of 3-hydroxybutyric acid was only moderately increased. This abnormal excretion pattern is consistent with a defect in the metabolism of acyl-CoAs and sarcosine. Normal activity of glutaryl-CoA dehydrogenase was found, excluding glutaryl-CoA dehydrogenase deficiency (glutaric aciduria type I).

Acyl Coenzyme A↗
PubMed1980

Citrullinaemia: the possibility of prenatal diagnosis.

Argininosuccinate synthetase activity in amniotic fluid cells from a fetus at risk for citrullinaemia was low compared to the activity in amniotic fluid cells from a normal fetus, but five times the activity in fibroblasts from a patient with citrullinaemia. These enzyme values indicated indicated a normal or heterozygous fetus. Chromosome analysis of the amniotic fluid cells from the fetus at risk, however, showed an unusual X/20 translocation. As we could not guarantee the delivery of a normal child, the parents chose to have a therapeutic abortion. Argininosuccinate synthetase activity in the liver and kidney of the aborted fetus was in the normal and heterozygous range respectively, confirming the prenatal diagnosis. The activity in the father's fibroblasts was low, less than 10% of normal. The difficulty of interpreting the results of prenatal diagnosis in such a family and the importance of studying parental cells are discussed.

Abortion, Therapeutic↗