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Biomedical subjects

L A Carlson

Publications and source records attributed to L A Carlson.

At least 163 records · Page 9Linked to original sources
PubMed1975

Conversion of type III hyperlipoproteinaemia to type IV hyperlipoproteinaemia by a fat-free, carbohydrate rich diet.

Hyperlipoproteinaemia type III has been considered a clear cut clinical entity characterized by the presence of cholesterol rich "floating" beta very low density lipoproteins (VLDL) after ultracentrifugation. Carbohydrate inducibility is pronounced in type III. This study was undertaken to elucidate the effect of a high carbohydrate diet in type III as an effort to clarify a suggested association between type III and IV hyperlipoproteinaemia. On an isocaloric fat free carbohydrate rich diet the lipoprotein pattern changed as the VLDL triglycerides increased 31 per cent on average and LDL and HDL cholesterol decreased by 40 and 22 per cent. The high ratio cholesterol/triglycerides in VLDL was normalized. The lipoprotein levels in serum after carbohydrate induction showed all characteristics of a type IV with high VLDL triglycerides, normal cholesterol/triglyceride ratio in VLDL, subnormal cholesterol levels in LDL and HDL with changed relation between LDL1 and LDL2. On electrophoresis the floating beta band disappeared. It is probable that depending on the nutritional situation, the metabolic defect in type III may be expressed either as a type III or a type IV. An explanation of the effects of the carbohydrate rich diet on the lipoprotein pattern is suggested.

Cholesterol↗
PubMed1975

Frequency of ischaemic exercise E.C.G. Changes in symptom-free men with various forms of primary hyperlipaemia.

Serum cholesterol and triglycerides were measured in approximately 12,000 men attending a screening centre. 130 symptom-free men (aged thirty-five to sixty-five) were selected from the top 2% with the highest lipid values. They, and 59 normolipaemic controls, were studied by recording electrocardiograms (E.C.G.) before and during exercise. The frequency of so-called ischaemic E.C.G. changes (ST-segment depressions Minnesota code 4.1-4.4) increased with age both in controls and in the hyperlipaemic group. Ischaemic E.C.G. changes were significantly more common in all types of hyperlipaemia (types IIA, IIB, III, and IV) than in controls. The high frequency of the exercise E.C.G. changes in symptom-free hyperlipaemic men reinforces the argument for early treatment of hyperlipaemia to prevent ischaemic heart-disease.

Adult↗
PubMed1975

Serum lipoprotein composition in different types of hyperlipoproteinemia.

Fasting serum lipoproteins (LP) were separated into VLDL, LDL and HDL by ultracentrifugation and the content of cholesterol and triglycerides analyzed in each LP class in 69 consecutive men attending a lipid clinic. The effect of using different cut off points in the definition of HLP was discussed. It was pointed out that by using lower values for the cut off points there is only an increase in the number of subjects with hyperlipoproteinemia (HLP) but also shifts in the proportions between the various types of HLP, particularly with increase in the amount of types IIB and IV. In addition to the LP abnormalities inherent in the definition of each type of HLP other LP abnormalities were observed. Thus type IIA HLP had cholesterol rich VLDL with an increased ratio cholesterol/triglycerides. The types of HLP with increased VLDL triglycerides had characteristic changes in both LDL and HDL. For LDL its triglyceride content was increased and HDL showed a lowering of its cholesterol content and a rise in triglycerides. These changes were more pronounced the higher the VLDL triglyceride concentration was. Both normo- and hyperlipoproteinemic subjects having the second pre-beta LP on agarose gel electrophoresis of the VLDL fraction called LPB (Late Pre Beta) had two characteristic LP features. VLDL had an increased cholesterol/triglyceride ratio. LDL had a raised triglyceride content. The relation of LPB to so called intermediary particles was discussed. When the SPB (Sinking Pre Beta) LP variant was present this had negligible effects on the LP composition. Type IIA was present in 14 percent of the 609 men. None had tendinous xanthomata. The LP pattern of this common type IIA was compared to the LP pattern of the uncommon type IIA where tendinous xanthomata are present, called IIA-X. Type IIA-X had much higher LDL cholesterol and in relation to the triglyceride content a more cholesterol rich LDL. Furthermore type IIA-X had lower VLDL lipids than the common type IIA, but type IIA-X was more cholesterol rich. The differences in clinical appearance as well as in quantitative and qualitative LP composition between the common type IIA and type IIA-X makes it important to separate these two types of HLP from each other.

Cholesterol↗
PubMed1975

Association between a low adipose tissue content of polyunsaturated fatty acids and both glucose intolerance and hypertriglyceridemia in apparently healthy men.

The fatty acid spectrum of adipose tissue (AT) lipids has been determined in 43 apparently healthy men with different levels of plasma triglycerides (TG) and different degrees of glucose tolerance (GT). Compared to men with normal plasma TG levels those with hypertriglyceridemia (HTG) had a similar percentage of linoleic acid (18:2) but lower amount of fatty acids, tentatively identified as linolenic (18:3) and arachidonic (20:4) acid. Men with HTG also had lower k-values for the i.v. GT. The content of 18:3 and 20:4 was positively correlated to the k-value of the GT and negatively to plasma TG. These correlations were independent of each other. As usual there was a negative correlation between plasma TG levels and the k-value, which however disappeared after partial correlation analysis when 18:3 was kept constant. Apparently a low content of 18:3 in AT is common both in HTG and glucose intolerance (GI) and might partly explain the often seen association between these two metabolic abnormalities. Since the content of 18:2 was normal it is suggested that the low amount of 18:3 and 20:4 was caused by metabolic rather than dietary factors. The possibility that a low content of 18:3 and 20:4 might play a role in the pathogenesis of GI and HTG is discussed.

Adipose Tissue↗
PubMed1975

Changes in insulin immunoreactivity across the coronary circulation in man during infusions of glucose and a fat emulsion.

The extraction of immunoreactive insulin by the human heart has been examined using the technique of coronary sinus catheterisation. The subjects were 12 male volunteers. During the study infusions of a fat emulsion and glucose were given in an effort to create a "steady fed state". The higher arterial insulin immunoreactivities which were observed during the infusions were associated with greater arterial coronary sinus differences in insulin immunoreactivity. The possibility of insulin degradation by the heart is discussed. During prolonged exercise the process of insulin removal by the heart appeared more active.

Adult↗
PubMed1975

Extraction of endogenous plasma triglycerides by the working human forearm muscle in the fasting state.

The extraction of triglycerides (TG) by the working forearm was determined in eight healthy fasting men, both by the measurement of chemical arterial-deep venous (a-dv) TG differences and by the a-dv differences in TG radioactivity after endogenous labeling with tritiated palmitate. Measurements were made before and then during nicotinic acid infusion. Correction for plasma water shift in the forearm vasculature was made by estimating the (125I)albumin activity after an intravenous injection. The overall mean value +/- S.E.M. without and with nicotinic acid was for TG arterial concentration (mumol/1) 713 +/- 153 and 695 +/- 140, TG a-dv concentration difference (mumol/1)-14 +/- 7 and -6 +/- 4, TG arterial radioactivity (cpm/ml) 1650 +/- 469 and 1471 +/- 342, TG a-dv radioactivity difference 12 +/- 24 and -2 +/- 13. The average standard errors for the determinations of triglycerides were 0.85% and 1.5% for the chemical and the isotope methods, respectively. In conclusion, no significant average a-dv difference in TG concentration as determined by either the chemical or the isotope method was detected. With the standard errors achieved, however, a-dv differences of less than around 20 mumol/lcould not be discovered. Such an extraction of endogenous plasma TG could, if oxidized, account for about 25% of the oxygen extraction by the eercising forearm.

Adult↗
PubMed1975

Studies in asymptomatic primary hyperlipidaemia. I. Types of hyperlipoproteinaemias and serum lipoprotein concentrations, compositions and interrelations.

1. In order to study lipoprotein (LP) abnormalities in asymptomatic subjects with hyperlipidaemia, serum cholesterol and triglycerides (TG) were determined in about 20 000 active professional men and women attending a health control linked to their employment. 2. Quantitative LP analysis with preparative ultracentrifugation, separating very low (VLDL), low (LDL) and high (HDL) density LP was subsequently performed on the sera of 314 asymptomatic subjects, who at the screening had serum cholesterol larger than or equal to 350 mg/100 ml and/or TG larger than or equal to 3.5 mmol/l. Cholesterol and TG concentrations were serum and on the top and bottom fractions after separation in the ultracentrifuge at d=1.006. Typing of hyperlipoproteinaemia (HLP) was based on the concentration of VLDL TG and LDL cholesterol and in addition, in the case of type III and V HLP, the presence of a "floating beta" LP and fasting chylomicronaemia, respectively. 3. To illustrate the lipid values in the screened total population distributions of serum cholesterol and TG are given in the age range 41-45 years. In this age range mean serum cholesterol in fasting/non-fasting state was 239+/-2/238+/-1 mg/100 ml in males and 232+/-2/239+/-2 mg/100 ml in females.

Adult↗
PubMed1975

Comparison of behaviour of very low density lipoproteins of type III hyperlipoproteinaemia on electrophoresis on paper and on agarose gel with a note on a late (slow) pre-beta VLDL liproprotein.

The diagnosis of type III hyperlipoproteinaemia is based on the presence of a very low density lipoprotein (VLDL) that on electrophoresis has beta instead of the usual pre-beta mobility. This definition is based on paper electrophoresis. Lipoproteins of type III sera were studied by simultaneous electrophoresis on paper and on agarose gel. On paper the ultracentrifugally isolated VLDL had beta mobility, but on agarose gel their mobility was slightly more rapid than beta. It is thus important to consider the electrophoretic conditions in the diagnosis of type III. The diagnosis of type III is further complicated by the presence of agarose gel electrophoresis - contrary to paper - of a second, a 'late pre-beta VLDL' lipoprotein (LPbeta) in 20-30 per cent of both normal and hyperlipoproteinaemic sera. Quantitative lipoprotein analysis of 609 consecutive sera showed that when LPbeta was present, both in normo- and hyperlipoproteinaemia, certain significant lipoprotein changes occurred. Thus VLDL had a high cholesterol content and a raised cholesterol to triglyceride ratio. Furthermore, the triglyceride content of low density lipoproteins (LDL) was increased. These lipoprotein abnormalities are also seen in type III hyperlipoproteinaemia. With regard both to chemical composition of VLDL and LDL and to electrophoretic mobility on agarose gel of VLDL, type III hyperlipoproteinaemia and LPbeta are similar. The possibility of a metabolic relation is discussed.

Cholesterol↗
PubMed1975

Serum lipoprotein abnormalities in ischaemic heart disease.

Quantitative lipoprotein level data was obtained from healthy subjects and patients with ischaemic heart disease or peripheral vascular disease in four European communities. Hypertriglyceridaemia, due mainly to an increase in VLDL triglyceride, was commoner in London and Uppsala than in Naples and Geneva. In three communities there were significant increases in total serum cholesterol due to both increases in LDL and in VLDL cholesterol. Hypercholesterolaemic and hypertriglyceridaemic status were over-represented in both ischaemic heart disease and peripheral vascular disease patients.

Cholesterol↗
PubMed1975

Cholestyramine, clofibrate and nicotinic acid as single or combined treatment of type IIa and IIb hyperlipoproteinaemia.

1. In type IIa and IIb hyperlipoproteinaemia, treatment with 16 g cholestyramine daily reduced the cholesterol concentration 23%. By adding clofibrate this effect was enhanced to a 29% reduction and at the same time clofibrate reduced the triglyceride (TG) concentration 33%. 2. The optimal cholesterol reduction with clofibrate in type II was 17% and was found after treatment with 1.5 g clofibrate/day. The optimal TG reduction appeared to be achieved with a daily dose of 2 g.3. Nicotinic acid in the form of niceritrol had another type of dose-response in type II with doses from 3 to 6 g/day. It appeared as if the optimal dose probably was above 6 g daily. The 6 g dose produced a cholesterol reduction of 22% and in type IIb there was at the same time a 50% reduction of the TG concentration. 4. By combining 3 g niceritrol with 2 g clofibrate almost the same effect on serum lipids was obtained as with 6 g niceritrol. When choosing a drug for treatment of hyperlipoproteinaemia it is necessary to consider not only the lipid lowering effect but also the side effects which are not discussed here. By combining clofibrate with either cholestyramine or niceritrol it was possible to improve the lipid lowering effect. There were no side effects which were not seen when the drugs were used alone. A more frequent use of combinations to improve the treatment of hyperlipoproteinaemia is recommended.

Cholestyramine Resin↗