Adipose tissue and skeletal muscle lipoprotein lipase and hepatic lipase activities in cholesterol-fed guinea pigs.

In control and in cholesterol-fed (1%) guinea pigs, the lipoprotein lipase activities of adipose tissue and skeletal muscle and the hepatic lipase activity were assayed after elution of the enzymes from tissues by heparin. The lipoprotein lipase activities were similar in the two groups of animals; the hepatic lipase activity was found be significantly increased in the animals fed cholesterol.

Serum lipoprotein(a) in patients with diabetes mellitus.

OBJECTIVE: To investigate subjects with different types of diabetes mellitus regarding their serum levels of lipoprotein(a). High serum Lp(a) concentration is associated with a high risk of coronary heart disease. Diabetic patients are prone to developing coronary heart disease. RESEARCH DESIGN AND METHODS: The subjects were 66 type I diabetic patients, 100 type II diabetic patients treated with diet alone or diet combined with oral hypoglycemic agents, and 46 insulin-requiring type II diabetic patients. Subjects were compared with 142 nondiabetic outpatients. RESULTS: Subjects with insulin-requiring type II diabetes mellitus were found to have an increase both in serum Lp(a) concentration and in prevalence of serum Lp(a) concentration > 30 mg/dl compared with the other groups of diabetic patients and nondiabetic control subjects. A nonsignificant increase in the prevalence of coronary heart disease was also found in insulin-requiring type II diabetic patients. The levels of serum concentrations of Lp(a) were not significantly related to the degree of glycemic control, duration of diabetes, presence of macrovascular disease, or intake of female hormone therapy. High levels of Lp(a) in this group of diabetic patients could not be explained by the presence of albuminuria. CONCLUSIONS: Insulin-requiring type II diabetic patients have high levels of Lp(a). Chronic hyperinsulinemia might be an eventual causal factor.

Variable regions of chromosome 11 loss in different pathological tissues of a patient with the multiple endocrine neoplasia type I syndrome.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited disorder characterized by nodular proliferation of the parathyroid glands and tumors of the anterior pituitary gland, the endocrine pancreas, and the neuroendocrine cell system of the gut. Loss of the putative tumor suppressor effect of the MEN1 gene is probably responsible for the development of MEN1-associated tumors. We report here a genetic study of a female MEN1 patient with the association of nodular hyperplasia of two parathyroid glands, an insulinoma, multiple duodenal gastrinomas, a prolactinoma, and a gastric carcinoid. We performed loss of heterozygosity (LOH) studies of chromosome 11 on all affected tissues except the insulinoma. Allelic losses of chromosome 11 were detected in several tumors, but the chromosomal regions of LOH were different, suggesting that different somatic mutational events are involved in the pathogenesis of these tumors. LOH of chromosome 11 was also detected in the prolactinoma of this patient, which indicates that the MEN1 gene has a tumor suppressor effect in the pituitary.

LDL oxidation: therapeutic perspectives.

The peroxidation step of lipid transormation is considered to be essential in the pathogenesis of atherosclerosis. Although data concerning the mechanisms by which lipid peroxidation occurs in vivo are scarce, several lines of evidence suggest that some endogenous and exogenous compounds with antioxidant activity could have some beneficial effects in the prevention of atherosclerosis. Ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E) act as the most important hydrophilic and lipophilic antioxidants, respectively in vivo. Accordingly, animal and human studies suggest that these compounds may have some preventive effect against the development of clinical coronary heart disease. Many plant phenols and flavonoids may be important dietary antioxidants and it has been speculated that these compounds in red wine or in the Mediterranean diet could explain the 'French paradox'. Several studies show that antioxidants such as probucol and butylated hydroxytoluene can inhibit development of atherosclerotic lesions in Watanabe and cholesterol-fed rabbits. Some drugs such as beta-blockers, calcium antagonists, hypolipodemic drugs,...appear to have at least in vitro antioxidant effects but the clinical relevance of these properties remains unkonwn. Moreover, some interventions aimed to decrease the LDL-oxidative susceptibility have not been shown to attenuate atherogenesis when cholesterol levels remain markedly elevated.

The use of Achilles tendon ultrasonography for the diagnosis of familial hypercholesterolemia.

Differentiating FH from other causes of hypercholesterolemia has important clinical and therapeutic implications but is often not possible by standard clinical criteria. As accumulation of cholesterol in tendon is generally considered as pathognomonic of FH, we evaluated the sensitivity and specificity of clinical and ultrasonographic tendon characteristics using the data of 127 genetically ascertained FH and 160 controls with various lipid profiles. Upon clinical examination, none of the controls and 29% of FH individuals (17% FH women and 38% FH men) presented with xanthomata in Achilles tendons, but no female and only 6% of male FH patients also showed xanthomata in the extensor tendon of the hand. Amongst all possible quantitative parameters (thickness, breadth, section and roundness) of Achilles tendon (AT) measured by ultrasonography, the thickness presented the best receiver operating curves. AT thickness above 5.8 mm was the most useful threshold for diagnosis of FH, procuring sensitivity of 75% and specificity of 85%. Analysis of variation of AT thickness with age and sex indicated that this clinical criterion performed better in females older than 45 and in males under 45. In patients carrying the APOB-R3500Q mutation, AT-thickness appeared significantly less important compared with those carrying LDLR mutations. In conclusion, this study recommends identification of possible FH individuals amongst hypercholesterolemic patients using a criteria of AT-thickness over 5.8 mm eventually associated with a specific genetic test for APOB-R3500Q mutation.

Plasma lipid concentrations and lecithin:cholesterol acyltransferase activity in normolipidemic subjects given fenofibrate and colestipol.

Plasma lipids and lipoprotein cholesterol concentrations and lecithin:cholesterol acyltransferase activity were measured in 7 normolipidemic subjects before, and 7 days after, the administration of fenofibrate (300 mg daily) and colestipol (15 g daily) taken separately or simultaneously. Fenofibrate provoked a significant decrease in the mean plasma triglycerides (26%) and cholesterol (10%) concentration; only plasma cholesterol concentrations were significantly lowered by colestipol (26%). The cholesterol lowering effects of the two drugs were additive as was observed when colestipol was added to fenofibrate. The mean plasma high density lipoprotein cholesterol (HDL-C) concentration was significantly increased by fenofibrate (10%) and when colestipol was added to fenofibrate (15%), but not by colestipol alone. Both fenofibrate and colestipol caused significant reduction of the mean plasma low density lipoprotein cholesterol (LDL-C) concentration and the mean plasma LDL-C/HDL-C ratio (13% and 18%, respectively, with fenofibrate, 44% and 52% with colestipol, and 53% and 62% with colestipol added to fenofibrate). The mean plasma fractional esterification rate was significantly increased by 25% and 12%, respectively, with fenofibrate and colestipol when taken separately, and still more (91%) when colestipol was added to fenofibrate. The mean plasma molar esterification rate was significantly lowered by colestipol, but remained unchanged with the other drug regimens. This study shows that fenofibrate and colestipol given to normolipidemic subjects can induce in a very short period of time (7 days) marked changes in lipoprotein metabolism. Interpretations of the findings in relation to lipoprotein metabolism are discussed.

Short-term effects of beta blockers atenolol, nadolol, pindolol, and propranolol on lipoprotein metabolism in normolipemic subjects.

The short-term effect of the blockade of the beta-adrenergic receptors on serum lipoproteins and the plasma activities of the enzymes involved in the metabolism of the serum lipoproteins: lipoprotein lipase (LPL), hepatic lipase (HL) and lecithin: cholesterol acyltransferase (LCAT) was evaluated in ten healthy normolipemic and normotensive subjects. In the first part of the study, the first three-day period of placebo was followed by another three-day period during which propranolol (120 mg/d) was given. In the second, third, and fourth part of the study, the same schedule was used but pindolol (15 mg/d), nadolol (160 mg/d), atenolol (100 mg/d) were given respectively instead of propranolol. The four drugs induced a significant blockade of the beta-adrenergic receptors as evaluated by the measurement of the double two-step test of Master (-45%). Despite similar blockade, the effect on serum lipid concentrations depended on the type of drug: propranolol induced an increase in triglycerides and apoprotein B-concentrations and a decrease in serum high density lipoprotein cholesterol (HDL-C) and apoprotein AI-concentrations. Pindolol provoked only a slight decrease of serum HDL-C concentration. Nadolol and atenolol elicited a lowering of the same magnitude in HDL-C. Except for a possible slight increase in plasma LCAT activity on propranolol, there was no significant change in the plasma activities of LPL, HL, and LCAT during the blockade of the beta-adrenergic receptors with the drugs used.(ABSTRACT TRUNCATED AT 250 WORDS)

Fast separation of the three main plasma lipoprotein classes by ultracentrifugation using vertical rotor and multiple discontinuous density gradient.

An ultracentrifugation technique for isolation of the various lipoprotein fractions using a vertical rotor is described. By the use of a multiple discontinuous density gradient, very low density lipoproteins, low density lipoproteins and high density lipoproteins are sharply separated, without contamination of other lipoproteins or albumin. Centrifugation time is 80 min. The densities, electrophoretic mobilities, electron microscopic appearance and chemical composition are those of the expected classes of lipoproteins. Two different gradients are used to enhance the separation of very low density lipoproteins from low density lipoproteins on one hand and high density lipoproteins from infranatant on the other.

An improvement of Barter's method for assaying plasma cholesterol ester transfer activity: experimental and clinical applications.

The use of a discontinuous density gradient and of a vertical rotor to separate plasma lipoproteins are modifications of Barter's described method for assaying cholesteryl ester transfer activity (CETA) in plasma. The original feature of our approach is the fast preparation of the labeled substrate by a physiologic-like process, which renders the assay easy and suitable for measurement of this activity in both man and animals.

Cholesterol esterifying capacity of various organs in cholesterol-fed guinea pigs.

In guinea pigs fed a diet enriched with 1% cholesterol, the liver, adrenals, spleen, and small intestine accumulated cholesterol much more than the lungs and kidneys. The cholesterol content of the aorta, stomach and colon was not increased by the diet. Cholesteryl ester was the predominant form of cholesterol deposited in the organs richest in this sterol and the total cholesterol content of a tissue tended to increase with the proportion of cholesteryl ester. Cholesterol esterifying activity (ACAT) was found in most tissues and paralleled the cholesteryl ester content of these tissues, being highest in the adrenals, liver, spleen and the proximal part of the small intestine. ACAT activity was enhanced by the cholesterol diet and its elevation was fairly well correlated with the increase in the cholesterol content of the organs. However, the liver and adrenals tended to accumulate more cholesterol than anticipated from their cholesteryl ester content and their ACAT activity. Cholesterol esterification may play a major role in the ability of organs to accumulate cholesterol.

[Hypoxic hepatitis. Prospective, clinical and hemodynamic study of 45 cases]. / Hépatite hypoxique. Etude prospective, clinique et hémodynamique de 45 épisodes.

The authors report 45 episodes of centrilobular liver cell necrosis, called ischemic hepatitis, in 43 cardiac patients. In 75 percent of the episodes, centrilobular liver cell necrosis was preceded by a period of progressive deterioration of myocardiac function. In 100 percent of the episodes, liver cell necrosis occurred after an acute clinical event inducing a transient fall of cardiac output. Shock was observed in only 47 percent of the episodes. The biological hallmarks of this centrilobular liver cell necrosis were a massive increase in serum aminotransferase levels and in 85 percent of the episodes, a decrease in the prothrombine time below 50 percent of control level. The mortality rate, 15 days after admission, was 42 percent. Prognosis was mainly related to cardiac function. The hemodynamic comparison between the 45 episodes of centrilobular liver cell necrosis and 22 cases of cardiogenic shock without liver cell necrosis showed that, besides hepatic ischemia, passive venous congestion of the liver and arterial hypoxemia were also involved in the onset of liver cell necrosis in these cardiac patients. Among these 45 episodes of liver cell necrosis of cardiac origin, a unique case of hepatic necrosis secondary to major hypoxemia and passive venous congestion, despite an high cardiac output was observed and is reported in detail. Accordingly, the appellation "hypoxic hepatitis" seems to be more appropriate than "ischemic hepatitis".

An unusual variant of Klippel-Trenaunay syndrome. Association of total hemihypertrophy, hemimegalencephaly and bilateral extremity enlargement (case report).

The case reported is the first description of an unusual form of Klippel-Trenaunay syndrome associating total hemihypertrophy to hemimegalencephaly and bilateral extremity enlargement. The patient complaints are related to her lower limb inequality; she presents dizziness, tinnitus and nystagmus which could be unusual consequences of hemimegalencephaly, disclosed at the EEG. Angiodysplasia is mild in regard to the hypertrophy whose cause is discussed.

[Unexplained fever or inflammatory syndrome. Diagnostic value of liver puncture-biopsy]. / Fièvre ou syndrome inflammatoire inexpliqués. Intérêt diagnostique de la ponction-biopsie hépatique.

The value of transcutaneous biopsy of the liver was assessed in a series of 110 cases of fever of unknown origin or of unexplained inflammatory syndrome. Liver histology was useful to the ultimate etiological diagnosis in 12 cases (11 per cent). The result of a transcutaneous biopsy of the liver was considered an essential aid to the ultimate diagnosis in 7 of these 12 cases. A hepatic lesion regarded as useless for the ultimate diagnosis was present in 16 cases (14.5 per cent). In the other cases, hepatic histology was normal or showed a non-specific reactive hepatitis. Unicteric cholestasis was present in 73 per cent of the cases but was of no predictive value for the detection of a useful hepatic lesion. On the other hand, serum transaminase levels were significantly higher when a useful lesion of the liver was observed.

[Lipoprotein (a) in liver diseases. Correlation between low levels and liver function]. / La lipoprotéine(a) dans les hépatopathies. Corrélation entre sa diminution et l'état fonctionnel du foie.

OBJECTIVES: To analyze the role of the liver function on the serum levels of lipoprotein(a) (Lp(a)), a lipoprotein considered to be a risk factor for atherosclerosis. METHODS: To measure the Lp(a) levels in patients with liver disease (n = 68) due to various causes and in patients with no liver disease and of similar age and sex-ratio (n = 62) and to analyze the relationship between Lp(a) levels on one hand and liver function and lipid and apoprotein levels on the other hand. RESULTS: Patients with liver disease had significantly lower levels of Lp(a). Lp(a) levels were significantly lower in patients with more severe liver disease (Child Turcotte classification) and significantly correlated with liver function tests, in particular those related to the microsomal function and the synthetic capacity of the liver (albumin, coagulation tests, apoprotein A-II). In patients with liver disease, mean Lp(a) levels were not significantly different between those with and those without chronic alcohol intake. CONCLUSIONS: Patients with liver disease have low levels of Lp(a) that are related to reduced synthetic capacity of this organ and are not linked to a specific cause of liver disease, in particular excess alcohol intake.

Management of familial hypercholesterolemia in children and young adults: consensus paper developed by a panel of lipidologists, cardiologists, paediatricians, nutritionists, gastroenterologists, general practitioners and a patient organization.

UNLABELLED: Since heterozygous familial hypercholesterolemia (HeFH) is a disease that exposes the individual from birth onwards to severe hypercholesterolemia with the development of early cardiovascular disease, a clear consensus on the management of this disease in young patients is necessary. In Belgium, a panel of paediatricians, specialists in (adult) lipid management, general practitioners and representatives of the FH patient organization agreed on the following common recommendations. 1. Screening for HeFH should be performed only in children older than 2 years when HeFH has been identified or is suspected (based on a genetic test or clinical criteria) in one parent.2. The diagnostic procedure includes, as a first step, the establishment of a clear diagnosis of HeFH in one of the parents. If this precondition is satisfied, a low-density-lipoprotein cholesterol (LDL-C) levelabove 3.5 mmol/L (135 mg/dL) in the suspected child is predictive for differentiating affected from non-affected children. 3. A low saturated fat and low cholesterol diet should be started after 2 years, under the supervision of a dietician or nutritionist.4. The pharmacological treatment, using statins as first line drugs, should usually be started after 10 years if LDL-C levels remain above 5 mmol/L (190 mg/dL), or above 4 mmol/L (160 mg/dL) in the presence of a causative mutation, a family history of early cardiovascular disease or severe risk factors. The objective is to reduce LDL-C by at least 30% between 10 and 14 years and, thereafter, to reach LDL-C levels of less than 3.4 mmol/L (130 mg/dL). CONCLUSION: The aim of this consensus statement is to achieve more consistent management in the identification and treatment of children with HeFH in Belgium.

Generics: need for clinical concern?

The market of generic drugs is in continuous development in all countries, including Belgium. Their low cost explains their success in western and developed countries. However, clinical concerns have been raised when generics are used. Indeed, various studies suggest that generic substitution can be associated with reduced efficacy or (and) increased side-effects, particularly with drugs used in severe diseases or pathological states such as epilepsy, cardiac arrhythmia, prevention of graft-rejection, ... The generic drugs must have systemic bioavailability similar to that of the original drug. Thus, they have supposed similar therapeutic bioequivalence. However, similar pharmacokinetics does not imply identical therapeutic activity, particularly with drugs having narrow therapeutic indices such as anti-epileptics, anti-arrythmics ... In this case, switchability rather than prescribability may cause problems. Low pharmaceutical quality is more frequent when drugs are produced in certain countries, in some cases causing a real concern when activity and safety are considered.