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Biomedical subjects

J Frohlich

Publications and source records attributed to J Frohlich.

At least 109 records · Page 6Linked to original sources
PubMed1982

A prospective study of 18 patients with cholestasis of pregnancy.

In this prospective study we evaluate the role of serum bile acids in the investigation and management of cholestasis of pregnancy in a detailed study of 18 patients. Bile acids were the most sensitive diagnostic test. The increased incidence of fetal distress (33.3% in this series) and meconium-stained fluid (58.3%) did not correlate with very high values of bile acids in maternal serum, umbilical cord serum, or amniotic fluid. Treatment of pruritus with cholestyramine and/or phenobarbital is ineffective in this condition, induction of labor is suggested once fetal lung maturity is established.

Adolescent↗
PubMed1982

Promotion of sterol efflux and net transport by apolipoprotein E in lecithin:cholesterol acyltransferase deficiency.

In the plasma of 4 subjects homozygous for deficiency of lecithin:cholesterol acyltransferase, the level of many apolipoproteins (apo A-I, apo A-II, apo B, apo D) was greatly relative to normal, while that of apo E is increased 5-fold. The lipoprotein complex containing lecithin:cholesterol acyltransferase with apo A-I and apo D in normal plasma is completely absent. The major part of apo E is unassociated with other apolipoproteins. The apoprotein-dependence of sterol efflux and net transport from human skin fibroblasts into plasma was determined by immunoaffinity chromatography. In normal plasma the major component of efflux of sterol radioactivity from labeled fibroblasts was dependent upon unassociated apo A-I. In LCAT-deficient plasma, apoprotein-dependent efflux was largely a function of unassociated apo E. When fibroblasts were incubated with fibrinogen-free unfractionated LCAT-deficient plasma, there was no spontaneous net transport of sterol either into or from the cells, indicating that efflux and influx rates were in balance. When apo E was removed by affinity chromatography, there was net transport from plasma to cells. These findings suggest a novel metabolic role for apo E in the promotion of sterol transport uncoupled to LCAT-activity.

Apolipoproteins↗
PubMed1982

Lecithin: cholesterol acyl transferase (LCAT).

Esterification of cholesterol in plasma is mediated by LCAT. The mechanism of the three reactions catalysed by the enzyme is beginning to be understood. LCAT has been purified from human plasma and partially characterized. The enzyme is closely associated with HDL and exists most likely as a complex with its activator apo A-I and apo D. Antibodies were raised against LCAT and the enzyme concentration in plasma has been estimated to range between 4.5 and 8.0 mg/L. In patients with familial LCAT deficiency only trace amounts or no LCAT protein is found. Heterozygotes for this disorder have approximately half the normal amount of the enzyme. LCAT reactivity is essential for normal lipoprotein metabolism and for a proper equilibrium between tissue and plasma cholesterol.

Animals↗
PubMed1982

Unusual renal biopsy findings in a patient with familial lecithin:cholesterol acyltransferase deficiency.

Familial lecithin:cholesterol acyltransferase deficiency is a rare autosomal recessive disorder associated with significant renal complications. A 16-year-old boy with the typical clinical and laboratory characteristics of this disease had a renal biopsy because of proteinuria and hematuria. The histologic findings were those of membranous glomerulonephritis with very few intracapillar foam cells. Ultrastructural study revealed numerous vacuolated deposits containing irregular profiles of electron-dense membrane-like material predominantly along with the subepithelial aspect of the glomerular basement membranes but also within the basement membranes, the subendothelial space, the mesangium, the capillary lumina, Bowman's capsule, and tubular basement membranes. The unusual aspects of this case are the relative paucity of intraglomerular foam cells and the predominantly subepithelial location of the lipid-like deposits.

Adolescent↗
PubMed1982

Detection of heterozygotes for familial lecithin: cholesterol acyltransferase (LCAT) deficiency.

"Rocket" immunoelectrophoresis using specific anti-lecithin: cholesterol acyltransferase (LCAT) antiserum showed no immunoreactive protein in two patients with familial LCAT deficiency. Subnormal quantity of plasma LCAT was found in the maternal grandmother, the parents, and in two of four siblings of the patients (3.3-3.4 mg/l vs. 5.4 +/- 0.5 mg/l in 12 controls). The immunochemical quantitation of the enzyme correlated well (r = .93) with LCAT activity in an artificial substrate assay. These two methods allow detection of heterozygotes for LCAT deficiency.

Female↗
PubMed1981

The effects of age, smoking, and alcohol on routine laboratory tests.

The effects of age, smoking, and alcohol intake on the results of some routine hematology and clinical chemistry tests have been determined for a group of 1,826 healthy male workers. Increasing age was significantly associated with higher hemoglobin, hematocrit, SGOT, BUN, and creatinine levels and with lower total protein concentration, but there was no significant association with leukocyte count, total bilirubin, or alkaline phosphatase. Smoking was significantly associated with higher hemoglobin, hematocrit, leukocyte count, and alkaline phosphatase, and with lower total bilirubin, SGOT, total protein, and BUN, but there was no significant association with creatinine levels. Alcohol consumption was significantly associated with higher hematocrit, bilirubin, and SGOT and with lower BUN and creatinine, but there was no significant association with hemoglobin, leukocyte count, alkaline phosphatase, or total protein. The possible reasons for these effects, and their implications, are discussed.

Adult↗
PubMed1981

Further studies on plasma proteins, lipids, and dye- and drug-binding in a child with analbuminemia.

A previously reported patient with analbuminemia was re-investigated after 4 1/2 years, at age 6. The serum albumin concentration was 150 mg/L by radioimmunoassay. Most of the observed increase in total plasma protein over the 4 1/2 years was attributable to gamma-globulin. Concentrations of total and high-density lipoprotein cholesterol were increased; the esterified:free ratio and the lecithin-cholesterol acyltransferase activity were both normal. Albumin is apparently not essential for binding of lysolecithin generated by the acyltransferase-catalyzed reaction. The binding of bromphenol blue suggested that analbuminemic serum has about 25% of normal binding capacity for bilirubin (more than expected in a patient with analbuminemia), which may explain why newborns with this disorder do not develop kernicterus. Binding by the patient's plasma of diazepam (1020 mg/L) and warfarin (1040 mg/L), which bind primarily to albumin, as well as of propranolol (1.05 g/L), which binds primarily to alpha 1-acid glycoprotein, was also studied. The proportions of free diazepam (14.4%) and warfarin (4.8%) were about 10-fold normal. In contrast, the proportion of propranolol in the free form was decreased (4.5%). Evidently, other plasma proteins are partly compensating for the deficiency of albumin.

Blood Proteins↗
PubMed1981

Erythrocyte alterations in praseodymium-induced lecithin:cholesterol acyltransferase (LCAT) deficiency in the rat: comparison with familial LCAT deficiency in man.

The intravenous administration of praseodymium nitrate (PrN) to rats was associated with parallel decreases in plasma lecithin: cholesterol acyltransferase (LCAT) activity and erythrocyte osmotic fragility at low doses (20 and 40 mg/kg) while higher doses (80 mg/kg) resulted in increases in both. Erythrocyte membranes from rats with PrN-induced LCAT deficiency exhibited small increases in cholesterol content, but not other alterations (e.g., in phospholipid profiles and sulfhydryl group latency) which characterize erythrocytes in familial LCAT deficiency in man. The administration of PrN caused a time- and dose-dependent accumulation of praseodymium in liver with hepatic levels being substantially greater in animals given the high (protective) as compared with the low (toxic) doses of PrN. Hepatic levels of glutathione were not altered by PrN administration, but hexobarbital sleeping time was markedly prolonged in animals receiving a toxic dose of PrN. It is suggested that dose-dependent alterations in the subcellular distribution of praseodymium may explain the paradoxical pathophysiological effects of high and low doses of PrN.

Animals↗