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Biomedical subjects

P Davidoff

Publications and source records attributed to P Davidoff.

17 recordsLinked to original sources
PubMed1991

[LP (a) lipoprotein: a new independent risk factor for atherogenesis].

LP(a) lipoprotein, discovered by Berg, appears as an independent risk factor for atherogenesis with a weight similar to that of the total to HDL cholesterol ratio. It is probably synthesized in the liver and its metabolism is similar to that of LDL; however degradation is preferential mediated by monocytes and macrophages. It is structurally related to plasminogen and may interfere with fibrinolysis. In vitro, its atherogenic power surpasses that of LDL. Elevated levels of LP(a) are inherited as an autosomic codominant trait. Increased atherogenic risk, both at coronary and cerebrovascular sites, is associated to plasma LP(a) levels in excess of 20 mg/dl. Its plasma level increases during pregnancy, after menopause, with renal failure and in decompensated insulin dependent diabetes. Plasma levels are decreased by stanozolol and chronic alcoholism. Diet therapy is of no value for control of high LP(a) levels; only neomycin associated to nicotinic acid has proven effective.

Arteriosclerosis↗
PubMed1991

[Cholesterol and triglycerides in atherosclerosis: epidemiologic and physiopathologic considerations].

Increased cholesterol levels above 200 mg/dl, LDL levels above 130 mg/dl and total cholesterol/HDL ratio above 4.5 in males and above 5.0 in females are recognized as indicators of increased risk of atherosclerosis. Risk associated to increased triglyceride levels (above 200 mg/dl) must be judged in relation to associated factors such as family history of coronary heart disease, presence of remnants (type III hyperlipidemia), presence of Lp(a), increased levels of Apo B, reduced levels of HDL2 or Apo A1. VLDL and chylomicron remnants and Lp(a) have an atherogenic power in vitro 2 to 4 times that of LDL. There is a correlation between hypertriglyceridemia and reduced HDL2 and Apo A1 levels. Hypertriglyceridemia is frequently associated to other risk factors like diabetes, obesity, hyperinsulinism, and high blood pressure. Finally, VLDL may elevate levels of plasma plasminogen inhibitor. Thus, hypertriglyceridemia should be investigated when, evaluating risk of atherosclerosis.

Arteriosclerosis↗
PubMed1991

[Acipimox in primary hyperlipidemias: safety and efficacy evaluated in six months].

The efficacy and tolerance of 750 mg of Acipimox was tested in 38 pts with primary dyslipidemias: 20 type IIa, 12 type IIb, and 6 type IV. All pts had been poor responders to a 2 month diet according to the recommendations of the National Cholesterol Education Program. Clinical examination, eye fundus, and the following laboratory tests: total cholesterol (TC), HDL, triglycerides (TG), total bilirubin, alkaline phosphatase, oxalacetic and pyruvic transaminases, uric acid, plasmatic creatinine, albumin, postprandial glucose test, hematocrit, white blood and platelet count were performed 60 days before drug initiation, 60 and 180 days after treatment had been started. No side effects were observed (myositis, visual gastrointestinal). 50% of the pts had slight to moderate flushing which appeared the first 3 days and lasted 14 +/- 7 days after treatment had been started. Plasmatic creatinine increased from 0.89 to 1.86 mg/dl in pt with one kidney, returning to normal levels 30 days after Acipimox interruption. After 180 days of therapy in the IIa group TC was -27% (p < 0.001), HDL + 15% (p < 0.001); in the IIb group: TC-23% (p < 0.001), HDL +9% (NS), TG -48% (p < 0.001); and in the IV group: TC-10% (p < 0.05), HDL +20% (p < 0.001), TG-53% (p < 0.001). Acipimox is well tolerated and is useful as a lipid-lowering drug in type IIa, IIb and IV dyslipidemias. Further studies are necessary to clear effects of the drug on renal metabolism and on long term survival of coronary pts.

Adolescent↗
PubMed1991

[Pharmacologic treatment of dyslipidemias: Analysis of initiation recommendations and drug selection].

According to the NCEP resins and nicotinic acid were selected as drugs of choice to treat hypercholesterolemia. Gemfibrozil and nicotinic acid were recommended for patients with HDL cholesterol below 35 mg/dl. Current concepts of efficacy and side effects lead to the following recommendations. a) type IIa severe hypercholesterolemia (LDL > 220 mg/dl): HGMC inhibitors or combined therapy with resins and nicotinic acid, fenofibrate, or bezafibrate. b) Moderate hypercholesterolemia (LDL < 220 mg/dl): bezafibrate and/or acipimox if HDL is < 35 mg/dl; fenofibrate, bezafibrate and/or acipimox if HDL > 35 mg/dl. As second line drugs, the HGMC inhibitors. c) Type IIb hyperlipidemia: first line, acipimox; second line, fibrates associated to acipimox. d) Type III hyperlipidemia: first line, fibrates; second line, an association of HGMC inhibitors and fibrates or acipimox. e) Type IV moderate hyperlipidemia (TG < 500 mg/dl): first line, acipimox, second line, fibrates alone or in association with acipimox. As general remarks, lovastatin has been effective and well tolerated in 98% of cases. Pravastatin seems to have very little side effects. Acipimox, a nicotinic acid derivative is especially effective in elevating HDL2b levels and decreasing LDL III. Given its adequate tolerance, acipimox has replaced nicotinic acid.

Female↗
PubMed1990

Unawareness of hypoglycemia by insulin-dependent diabetics.

After several years of insulin therapy, about 20% of insulin-dependent diabetics have little or no perception of hypoglycaemia because of a loss of the adrenergic warning symptoms. This defect, poorly correlated with the presence of autonomic neuropathy, has been classically explained by a defect in the catecholamine secretion. We compared the hormonal counterregulation during hypoglycaemia induced by subcutaneous injection of insulin in 7 insulin-dependent diabetics with poor perception of hypoglycaemia and experiencing repeated episodes of severe hypoglycaemia (group A) and 7 insulin-treated diabetics with very good perception of hypoglycaemia and not experiencing severe hypoglycaemia (group B). Groups A and B were similar in terms of age, duration of diabetes, HbA1c level and degenerative complications. The glucagon levels were identical and non-reactive in the two groups. The basal levels and secretion peaks of adrenaline, noradrenaline, growth hormone and cortisol were similar between the two groups, but there was a significant delay in secretion in group A with a blood glucose threshold of adrenergic secretion of between 3.1 +/- 0.5 and 1.6 +/- 0.2 mmoles/l in group A and between 4.6 +/- 0.3 and 3.2 +/- 0.2 mmoles/l in group B (P less than 0.05). This delayed secretion could be explained by desensitisation of the hypothalamic glucostat and could be due to the frequency and/or severity of hypoglycaemic episodes.

Adult↗
PubMed1989

[Screening of subjects at high risk for diabetic microangiopathies].

Chronic hyperglycemia is the single most important pathogenic factor in the diabetic triad: retinopathy, glomerulopathy and neuropathy. But at equal serum glucose balance, diabetics are not equally at risk of microangiopathy. Hence the importance of timely screening of patients who should be convinced to accept the constraints and risk of perfect serum glucose balance or to whom specific therapy independent from serum glucose balance could be proposed. But at present, there is no genetic or immunologic marker allowing for the individual identification of at risk patients. Attention is thus directed towards factors which may be directly involved in the pathogenesis of diabetic microangiopathy: --Special sensitivity of vascular collagen to protein glycosylation which could be reflected in the involvement of tendon and aponeurotic collagen, --platelet abnormalities of which the exacerbating role appears to be confirmed by the significant efficacy of aspirin in the treatment of nonproliferative retinopathy in insulin-independent diabetics, --rheological abnormalities which might essentially be secondary to chronic hyperglycemia, --hormonal abnormalities, in particular hypersecretion of growth hormone and/or somatomedin C, whose role has long been suspected and could be established by therapeutic trials with new somatostatin analogues. But the most recent advances concern the study of hemodynamic factors. Irreversible organic diabetic microangiopathy is thought to be preceded by a phase of reversible functional microangiopathy, characterized by increased capillary blood flow, vascular dilatation, hyperpermeability and altered regulation of flow. Thus, diabetic glomerulopathy with decreased glomerular filtration is preceded by a phase of renal "hyperfunctioning" and irreversible proteinuria is the outcome of a progressive increase in microalbuminuria, reversible at least while the levels are not too high.(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetic Angiopathies↗
PubMedDate not supplied

[Lipoprotein Lp(a): a new risk factor of atherogenesis].

Lp(a) is a lipoprotein present in all individuals in concentrations that are genetically determined. Its structure is characterized by the presence of an apoprotein with a high carbohydrate content called apoprotein a. Since 1972, numerous concordant data have endowed Lp(a) with a high risk of atherogenesis. This risk applies to the coronary and cervico-encephalic arteries. For the latter, Lp(a) even is a lipid parameter regarded as a major risk factor. The origin and metabolism of Lp(a) are little known, by they seem to differ from those of low-density lipoproteins. Its specific apoprotein of Lp(a). At the moment, there is no simple dietetic or medicinal treatment that can lower substantially the serum level of Lp(a).

Arteriosclerosis↗