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Biomedical subjects

G M Berger

Publications and source records attributed to G M Berger.

At least 55 records · Page 3Linked to original sources
PubMed1983

Apolipoprotein B detected in the plasma of a patient with homozygous hypobetalipoproteinaemia: implications for aetiology.

A hypobetalipoproteinaemic kindred is described in which the proband manifested the clinical and biochemical features of the homozygous state. Unlike the apparent complete absence of apolipoprotein B in the plasma of the five cases of homozygous hypobetalipoproteinaemia reported so far, we were able to demonstrate minute quantities of this protein (approximately 0.025% of normal) in the plasma of the proband. This finding suggests that the disorder may not result from a structural gene defect but may rather reflect a failure of secretion.

Apolipoproteins↗
PubMed1983

Absence of serum-stimulated lipase activity and altered lipid content in milk from a patient with type I hyperlipoproteinaemia.

We measured the serum-stimulated lipase activity, fatty acid content, and various biochemical parameters in the breast milk of a lactating mother suffering from familial lipoprotein lipase deficiency and of healthy control subjects. Serum-stimulated lipase activity was virtually undetectable in milk from our patient and the total fatty acid content was low. The fatty acid composition differed from normal showing a marked absolute and relative increase in the content of lauric (C12:0) and myristic (C14:0) fatty acids and considerably reduced levels of oleic (C18:1) and especially linoleic (C18:2) acids. Other fatty acid species showed lesser changes in concentration. Besides a reduced calcium concentration in the milk from our patient, other biochemical parameters were not significantly different from control subjects.

Adult↗
PubMed1982

Chylomicron and very-low-density lipoprotein levels in type I hyperlipoproteinaemia. The role of the liver in determining biochemical phenotype.

Patients with type 1 hyperlipoproteinaemia present with relatively normal plasma levels of very-low-density lipoprotein (VLDL) together with marked hyperchylomicronaemia. Since the aetiological basis for the type 1 phenotype is a severe reduction in peripheral lipoprotein lipase (LPL) activity, the discrepancy between the two triglyceride-rich lipoprotein fractions is paradoxical. In order to account for these observations we have previously proposed (G.M.B) that the hepatic secretion of lipoproteins in these patients is characterized by the production of chylomicron-like particles rather than VLDL. The implications of this hypothesis were examined in 3 patients with type 1 hyperlipoproteinaemia. A high-carbohydrate diet led to the enhancement of hyperchylomicronaemia in 2 of the 3 subjects. The severity of the defect in peripheral LPL activity correlated with the tendency to hyperchylomicronaemia, and in vitro assay suggested that hepatic lipase was capable of hydrolysing chylomicron triglyceride when present at the high concentrations characteristic of type 1 hyperlipoproteinaemia. These results were compatible with the above hypothesis implicating the liver as a partial determinant of the type 1 phenotype.

Adolescent↗
PubMed1981

Iatrogenic hyperosmolality in a neonate. A case report.

An infant presented in the first week postpartum with markedly elevated serum osmolality of unknown origin. The cryptic osmols were identified as glycerol and alcohol and were traced to the contents of local phenobarbitone elixir administered to control neonatal convulsions. This report highlights the importance of recognizing the potential dangers inherent in the nominally inert components of medication and stresses the extreme care required when modifying well-established formulations.

Drug Combinations↗
PubMed1979

Galactosaemia in three Rhodesian infants.

The clinically relevant types of genetic galactosaemia involve deficiency of galactose-1-phosphate uridyltransferase (EC 2.7.7.12) or galactokinase (EC 2.7.1.6). Specific diagnosis is made by quantitative assay of these two enzymes. Seven Black patients were referred from Harare Hospital, Rhodesia, with features suggestive of galactosaemia. Enzyme assay identified classic homozygous transferase deficiency in 3 of these patients. The incidence in this population was calculated to be 1:52 000.

Clinical Enzyme Tests↗
PubMed1979

Why very low density lipoprotein levels are normal in familial hyperchylomicronaemia.

The anomalous finding that very low density lipoprotein levels are relatively normal in patients with familial hyperchylomicronaemia has never been satisfactorily explained, particularly in view of the marked reduction or absence of peripheral lipoprotein lipase activity characteristic of this condition. I propose that the discrepancy between the plasma levels of the two triglyceride-rich lipoprotein fractions in these patients is due to the secretion by the liver of triglyceride in the form of chylomicron-like particles, rather than as very low density lipoprotein. The proposed "switch" in the spectrum of lipoproteins secreted by the liver is probably contingent upon the activity of the hepatic lipase present on the liver cell plasma membrane.

Cholesterol↗
PubMed1978

High-density lipoproteins in the prevention of atherosclerotic heart disease. Part I. Epidemiological and family studies.

It has recently been proposed that the concentration of the high-density lipoprotein (HDL) fraction in plasma bears a negative relationship to the incidence of atherosclerotic heart disease. The biological and environmental factors affecting plasma HDL levels and the evidence pertaining to the proposed 'negative risk potential' of this lipoprotein are reviewed. HDL concentrations are low at birth, but rise rapidly in early infancy to adult or above-normal adult levels. This trend is influenced by biological factors such as sex and ethnicity and by a host of environmental variables. Despite methodological inadequacies in some studies, the epidemiological evidence consistently reflects an inverse relationship between the level of HDL in the plasma and the risk of ischaemic heart disease. Investigations on families suffering from genetic dyslipoproteinaemias, characterized by reduced levels of low-density lipoprotein (LDL) relative to HDL, suggest that the LDL:HDL ratio is itself an important determinant of atherosclerotic heart disease. The practical application of this information is limited by the lack of reliable reference ranges in various population groups and the absence of quantitative data regarding the 'negative risk potential' of any given concentration of plasma HDL in the presence of other positive and negative risk factors.

Adolescent↗
PubMed1978

High-density lipoproteins in the prevention of atherosclerotic heart disease. Part II. Biochemical role in the pathogenesis of atherosclerosis.

Evidence is presented that high-density lipoprotein (HDL) promotes the efflux of cholesterol from cells in vitro, and may thus play an important role in the transport of cholesterol from non-hepatic tissues to the liver for excretion. Hypothetical schemes are presented whereby this may be achieved in vivo. This putative function of HDL may be of particular importance in situations in which the capacity of cells to limit the uptake of cholesterol is exceeded, and may therefore constitute the basis for the proposed antiatherogenic action of plasma HDL. However, direct data on the transport function of HDL in intact organisms are meagre. Furthermore, a characteristic of mature atherosclerotic lesions is the extracellular, rather than the intracellular, deposition of cholesterol and other lipids, and the degree to which HDL may influence this process has not been demonstrated. Finally, in inherited disorders which markedly impair the putative HDL transport pathway, atherosclerotic heart disease is generally not an early or severe complication. Despite these caveats, the physiological significance of HDL deserves further attention in order to clarify the uncertainties enumerated above. The clinical application of plasma HDL assay is limited at present to excluding the clinically non-deleterious condition of hyperalpha (HDL)-lipoproteinaemia in patients suffering from familial hypercholesterolaemia.

Adrenal Cortex↗
PubMed1978

Continuous flow plasma exchange in the treatment of homozygous familial hypercholesterolemia.

We report the clinical and laboratory effects of continuous-flow plasma exchange in two patients suffering from homozygous familial hypercholesterolemia. In one (Case 1) plasmapheresis was performed at fortnightly intervals over a period of 18 months; in the other (Case 2) the necessity for surgical relief of an associated supravalvular aortic stenosis resulted in premature termination of the trial. The plasma cholesterol levels in both patients fell by 35 per cent from the mean before study in the course of treatment. In Case 1 this was associated with marked regression of the patient's xanthomas, disappearance of the S-T segment depression seen on effort electrocardiograms obtained prior to the introduction of plasmapheresis, possible widening of the stenosis present at the origin of the left anterior descending coronary artery, and a marked increase in exercise tolerance and diminished frequency of anginal attacks. Cessation of cholestyramine and clofibrate administration during this study did not in any way reverse the reduction of plasma cholesterol achieved by means of plasmapheresis combined with drug therapy. We conclude that plasmapheresis has a role to play in the management of patients with homozygous familial hypercholesterolemia.

Adolescent↗
PubMed1977

Selective protamine sulphate inactivation of lipoprotein lipase and hepatic lipase in human post-heparin plasma: specific lipase levels in normals and in type I hyperlipoproteinaemia.

The rate of inactivation of triglyceride hydrolase activity by protamine sulphate was determined in pooled, normal, post-heparin plasma. Two distinct first-order rates of inactivation were obtained and the derived constants used to calculate the lipoprotein lipase and hepatic lipase contributions to the total post-heparin triglyceride hydrolase activity in normal controls and in patients with familial hyperchylomicronaemia. The lipoprotein lipase was reduced in the patients whereas the hepatic lipase was normal. There was however a marked age-related increase in the hepatic enzyme activity in normal subjects. Post-heparin lipolytic activity, assayed in vitro against lipoproteins of d less than 1.006 derived from the patients, was markedly reduced in our hyperchylomicronaemic subjects. This assay correlated well with the lipoprotein lipase activity determined by selective protamine sulphate inactivation.

Adolescent↗
PubMed1977

Familial hyperchylomicronaemia in four families. Problems in diagnosis, management, and aetiology reviewed.

We report on the clinical and biochemical findings of 8 patients with familial hyperchylomicronaemia (type I hyperlipoproteinaemia) from 4 separate kindreds. The diagnosis is generally easily established by the presence, in standing plasma, of a creamy chylomicron layer over a clear infranatant and by the large predominance of triglycerides over cholesterol in the plasma. Additional aids are the presence of chylomicrons on lipoprotein electrophoresis and the markedly reduced liberation of lipolytic activity into the plasma of these patients, after the administration of heparin. Difficulties in diagnosis may arise in patients on reduced fat diets, resulting in an increase of very low density lipoproteins and a type IV or V phenotype. The precise nature of the primary genetic defect remains to be established but the disorder appears to be aetiologically distinct from type IV or V hyperlipoproteinaemia. Reduction of chylomicron, and hence of triglyceride values in the plasma, is wholly dietary.

Adolescent↗
PubMed1977

Experience with the EMIT method of determining anticonvulsant levels in serum.

Clinical and laboratory experience with the EMIT immunoassay method for the determination of serum phenobarbitone levels is reported. A modification of the published laboratory method permitting manual operation in a general clinical chemistry laboratory was used. In 42 of the 75 children monitored, the serum levels of phenobarbitone indicated a change of the prescribed dosage.

Adolescent↗
PubMed1976

Amylase: creatinine clearance ratio and urinary excretion of lysozyme in acute pancreatitis and acute duodenal perforation.

The amylase:creatinine clearance ratio in patients suffering from acute pancreatitis or acute duodenal perforation was higher than normal in both groups of patients. These findings cast doubt on the value of this parameter as a specific index of acute pancreatitis. The mechanism or mechanisms underlying the increased amylase excretion have not been determined. However, the markedly elevated urinary excretion of lysozyme observed in some patients suggests, by analogy, that diminished tubular reabsorption of amylase may contribute towards the elevated amylase:creatinine ratio.

Acute Disease↗
PubMed1976

Portacaval shunt in two patients with homozygous type II hyperlipoproteinaemia.

We report the clinical and biochemical course of 2 patients who underwent portacaval shunting for the relief of homozygous type II hyperlipoproteinaemia. In our first patient, the initial favourable clinical and biochemical response subsequently deteriorated and a splenoportogram revealed the presence of a blocked splenic vein with a large collateral blood supply to the liver. The second patient has responded quite dramatically; there has been relief of her preoperative anginal attacks and a significant fall in her plasma cholesterol concentration. The present role of portacaval shunts in the management of this conditions is discussed.

Child, Preschool↗
PubMed1976

Alpha fetoprotein in the antenatal diagnosis of the congenital nephrotic syndrome.

In the congenital nephrotic syndrome (Finnish type), concentrations of alpha fetoprotein in the amniotic fluid and maternal serum are markedly elevated in the second trimester of pregancncy. Demonstration of this alteration allows early prenatal diagnosis of this fatal condition and elective termination of the pregnancy before 20 week's gestation.

Adult↗