Simplified method for the detection of apo(a) isoforms.

Apolipoprotein a, is a high molecular weight glycoproteic component of Lp(a), a molecule associated with coronary arterial disease. Apo(a) exhibits considerable size heterogeneity due to variable repetitions of the carbohydrate-containing structural unit, termed kringle. There are five different kringle forms and 10 different kringle 4 types. Apo(a) polymorphism and molecular weight depend on the number of copies of kringle 4 type 2. In this paper we describe a modified 3.75% and 6% discontinuous polyacrylamide gel system and Western-blot technique that shortness the assay time and improves the identification of apo(a) isoforms with a theoretical error of less than 1 kringle. The assay uses a standard curve prepared with five different recombinant apo(a) molecules, detected up to 50 ng of protein in Lp(a), showed a maximal resolution of 2 kringles and, with the use of third degree polynominal regression analysis, had an error of 0.01275. The inter-assay coefficient of variation was 1.7, 2, and 1.4 for the 14 K, 18 K, and 22 K phenotypes, whereas the intra-assay coefficient of variation was 0.32%, 0.18%, and 0.17%, respectively. It is possible that this modified method will diminish the number of putative null alleles so far detected in various studies, but most of all, we are certain that it can be of use in epidemiological studies due to its ease of use, speed, low cost, and enhanced number of samples that can be tested.

Masa ósea medida con radiogrametría en una muestra de mujeres limeñas sanas / Bone mass measured by radiogrammetry in a sample of healthy women from Lima

Para determinar la curva de masa ósea normal y sus cambios con la edad, evaluamos a 147 mujeres sanas, cuyas edades fluctuaron entre 20 y 88 años, todas de raza mestiza, elegidas al azar, empleando la técnica de la radiogrametría. Con el fin de obtener los valores del espesor de la cortical, todas fueron sometidas a una radiografía de mano derecha según las técnicas estandarizadas. La medición del valor del espesor de la cortical (D-d) se realizó en el punto medio del segundo metacarpio derecho, para lo cual se restó del diámetro periosteal (D) el diámetro endosteal (d), los que se midieron mediante una lente de aumento milimetrada, por un observador debidamente instruido y entrenado en la medición de dichas placas. Los valores promedios del diámetro periosteal (D) por grupos etáreos fueron: de 20 a 34 años: 7,78 mm; de 35 a 44 años: 7,88 mm; de 45 a 54 años: 8,02 mm; de 55 a 64 años: 7,94 mm; de 65 a 74 años: 7,77 mm y de 75 a más: 8,06 mm. Los valores promedios del diámetro endosteal (d) por grupos etáreos fueron: de 20 a 34 años: 3,21 mm; de 35 a 44 años: 3,09 mm; de 45 a 54 años: 3,68 mm; de 55 a 64 años: 4,35 mm; de 65 a 74 años: 4,44 mm; y de 75 a más: 5,12 mm. Los valores promedios del espesor de la cortical (D-d) por grupos etáreos fueron: de 20 a 34 años: 4,57 mm; de 35 a 44 años: 4,79 mm; de 45 a 54 años: 4,34 mm; de 55 a 64 años: 3,58 mm; de 65 a 74 años: 3,33 mm; y de 75 a más: 2,96 mm. Un hallazgo importante fueron los cambios en los promedios encontrados en las mediciones del diámetro periosteal (D) y diámetro endosteal (d) con la edad, mientras que el diámetro periosteal se mantuvo uniforme, el endosteal se incrementó con la edad, causando la disminución progresiva del espesor de la cortical conforme se aumentaba la edad. El pico máximo de masa ósea que alcanzó nuestra población femenina limeña sana fué entre los 35 a 44 años, mientras que la menopausia se presentó como edad promedio a los 45 años, momento a partir del cual, empieza a disminuir progresivamente la masa ósea. Estos hallazgos concuerdan con los encontrados en las diferentes poblaciones estudiadas, siendo muy similares a las reportadas en la población española.

[Fasting and postprandial lipids and lipoproteins during the chronic administration of antihypertensive drugs]. / Lípidos y lipoproteínas de ayuno y postprandiales durante la administración crónica de fármacos antihipertensivos.

To evaluate the effect of various antihypertensive drugs on fasting and postprandial lipids and lipoproteins, we studied 39 normolipidemic hypertensive patients, 28 men and 11 women aged 52.3 +/- 9.0 and 58.5 +/- 7 years, respectively. After four weeks of placebo administration, lipids and lipoproteins were measured in the fasting state and every three hours for a period of nine hours after intake of a standardized fat mixed load (65 g/m2). Following this test, the patients were randomly assigned to one of four treatment groups: group I metoprolol (n = 10), 100 mg/day; group II nicardipine (n = 9), 90 mg/day; group III captopril (n = 11), 75 mg/day. At the end of week four of treatment the fasting and postprandial lipid measurements were repeated. Blood pressure mean values were significantly (p < 0.05) reduced in the four treatment groups. We found no statistically significant lipids or lipoproteins changes neither in the fasting nor in the postprandial state, but a trend toward lower concentrations in the postprandial lipemia after treatment was observed in three groups (metoprolol, nicardipine and captopril), whereas no change was observed in the chlorthalidone group. These data confirm that fasting lipids and lipoproteins in normolipidemic hypertensive patients are not unfavorably changed by low doses of the drugs studied. In addition, we inform that postprandial lipemia is not affected by these four drugs in the doses used.

Long distance runners and body-builders exhibit elevated plasma levels of lipoprotein(a).

A one-point cross-sectional study of 20 sedentary individuals, 20 low-aerobic athletes (body-builders), and 20 high-aerobic athletes (long distance, endurance runners) was conducted in Mexico City, Mexico to determine the influence of these diverse life-styles on the plasma levels of Lp(a). Only non-obese male subjects, aged 23-33, who were nonsmokers, non-alcoholics, and had never used anabolic steroids were included in this study. Blood samples were drawn 24 h following the last period of physical activity, and after a 12-14-h fast-period and a 15-min sitting-rest. Plasma levels of Lp(a) and other parameters, including postheparin lipoprotein lipase (LPL) and hepatic lipase (HL) activities, triglycerides (TG), total cholesterol (TC), LDL cholesterol (LDL-C), and HDL cholesterol (HDL-C), as well as % body fat and muscle mass, and maximum aerobic capacity (VO2max) were measured to determine possible correlations with Lp(a) and to serve as convenient internal standards. Mean Lp(a) concentrations were significantly higher in the runners (52 +/- 19 mg/dl) than in the body-builders (40 +/- 6.4 mg/dl, P < 0.05) and the sedentary subjects (24 +/- 5 mg/dl, P < 0.001). Positive correlations between Lp(a) and Vo2max (P < 0.001), HDL-C (P < 0.005) and HDL2-C subfraction (P < 0.005), and a negative correlation with TG were determined. Agglomerative cluster methods suggested three close-distance clusters and a fourth cluster which is composed of four runners who exhibited low LDL-C/HDL-C and high LPL/HL ratios, high mean Lp(a), HDL2-C, and Vo2max levels, but low TG levels. These data show that some individuals who maintain a life-style of very high level physical exertion may have remarkably elevated plasma Lp(a) concentrations. The highly increased concentrations of Lp(a) in high exercise athletes may represent a normal metabolic response to repeated small tissue injuries resulting from frequent and prolonged large muscle movement.

[Premature atherosclerosis in a 17-year-old male with diabetes mellitus and familial dyslipoproteinemia]. / Aterosclerosis prematura en un joven de 17 años con diabetes mellitus y una dislipoproteinemia familiar.

A 17-year-old male was admitted with an acute myocardial infarction. A coronarography showed 90% occlusion in of the descendent anterior artery. A coronary angioplasty was done with excellent response. As coronary risk factors he had diabetes mellitus for 5 years and dyslipidemia with a phenotype IIb and hypo-alpha-lipoproteinemia. The case is discussed in regard to the possible etiopathogenic causes for his premature atherosclerosis.

[Effects of aerobic physical conditioning on the profile of plasma lipoproteins in a group of healthy volunteers]. / Efectos del acondicionamiento físico aeróbico sobre el perfil de lipoproteinas plasmáticas en un grupo de voluntarios sanos.

To evaluate the effects of aerobic physical conditioning on plasma lipoproteins, we studied 26 previously untrained, apparently healthy, non obese volunteers. All participants underwent a treadmill test performed according to the protocol of Bruce with the direct measurement of maximal oxygen consumption (VO2max). A program of aerobic exercise was prescribed for each volunteer at 70% of their corresponding VO2max. At baseline and at the end of weeks 4, 8 and 12 of the exercise program, cholesterol and triglycerides were measured by enzymatic analysis in total plasma and in the lipoprotein fractions separated by preparative ultracentrifugation and precipitation methods. At the end of week 12, the VO2max measurement was repeated. At the end of the protocol, mean VO2max increased from the value of 39.9 observed at baseline to 94.4 ml/kg/min (p less than 0.01). There were no variations in mean body weight, diet or smoking status of the participants during the exercise program. Cholesterol associated with High-density lipoproteins (C-HDL) increased from 42.5 to 46.1 mg/dl (p less than 0.05). This effect was first noticeable at week 8. We didn't observe significant changes in Total Cholesterol nor the Cholesterol fraction associated with Low-density lipoproteins (C-LDL). Total triglycerides decreased at weeks 4 and 8 but returned to near baseline values at week 12. The C-LDL/C-HDL ratio considered as an index of a high coronary risk decreased from 2.32 at baseline to 2.02 (p less than 0.05) at week 12. Thirteen of the twenty six initial volunteers completed the physical conditioning program as planned, the rest were eliminated at different stages of the protocol due to incomplete adherence to their exercise schedules.(ABSTRACT TRUNCATED AT 250 WORDS)

[Autoimmunity in thyroid disease secondary to amiodarone: heredofamilial aspects]. / Autoinmunidad en distiroidismo secundario a amiodarona: aspectos heredofamiliares.

Spontaneous autoimmune thyroid disease (SATD) shows familial aggregation. Some patients receiving amiodarone treatment have been found to develop thyroid dysfunction. Previously, we reported genetic predisposition among this group of patients, now we inform a prospective study which includes the search for autoantibodies and family history to identify risk factors in amiodarone treated patients, 40 of them with amiodarone related thyroid disfunction, and 100 without it; for comparison, 30 patients with SATD and a control group of healthy subjects were also studied. We looked for the presence of autoantibodies against thyroglobulin, smooth muscle, gastric mucosa, myocardium, mitochondria, epithelial intercellular substance, and basal membrane as well as antinuclear antibodies and rheumatoid factors; in addition the history of thyroid disease in first degree relatives was investigated. Organ-specific antibodies anti-thyroglobulin, gastric mucosa and myocardium were found with increased frequency in the three groups of patients compared with controls (p less than 0.05). The frequency of antihydroglobulin antibodies was similar in patients receiving amiodarone with or without thyroid dysfunction. Prognostic stratification revealed that this finding is independent of sex, age, dosage or duration of treatment. A family history of thyroid dysfunction was found more frequently among patients with SATD and amiodarone related dysthyroidism in comparison with patients receiving amiodarone without altered thyroid function (p less than 0.005). The appearance of clinical thyroid disease depends on individual genetical predisposition. In patients with a positive family history, the risk of developing clinical, thyroid disease is 7.6 when treated with amiodarone.

Effect of pertussis toxin on the heart muscarinic-cholinergic receptors and their function.

Administration of pertussis toxin to rats induced a significant increase in heart rate that was evident as soon as 24 hours after the administration of the toxin and that persisted for at least 15 days. Electrical stimulation of the vagus decreased dramatically the heart rate of control animals but was unable to do it so in rats treated with pertussis toxin. In cardiac membranes muscarinic agonists decreased adenylate cyclase activity (approximately equal to 20-25%); no effect was observed in membranes obtained from toxin-treated animals. Agonist displacement of antagonist binding [( 3H] Quinuclidinyl benzilate) indicated that treatment with pertussis toxin decreased the proportion of receptors in the high affinity state for agonists. All these data suggest that blockade of the parasympathetic tone plays a key role in the induction of tachycardia by pertussis toxin.

Effect of pertussis toxin on the heart acetylcholine muscarinic receptor affinity.

The effect of pertussis toxin on the affinity for agonists and antagonists of the heart muscarine acetylcholine receptor was studied using the radiolabeled antagonist [3H]quinuclidinyl benzylate ([3H]QNB). In cardiac membranes from control rats the displacement of [3H]QNB by carbachol was consistent with two classes of binding sites, kDH 25 +/- 10 nM and kDL 3,006 +/- 869 nM. The proportion of sites in the high and low affinity state for agonists was 55 and 45% respectively. In the presence of 100 microM guanyl-5'-yl imidodiphosphate (Gpp(NH)p), only the low affinity state for agonists was observed (kDL 3,804 +/- 759 nM). In cardiac membranes from pertussis toxin-treated rats, two classes of binding sites with affinities similar to those seen in the controls were also observed in the absence of guanine nucleotide (kDs 39 +/- 12 and 3,315 +/- 845 nM) but the proportion of sites were 20 and 80% for high and low affinity respectively. Gpp(NH)p shifted the remaining 20% of sites from the high affinity to the low affinity state (KD 4,093 +/- 744 nM). The receptor KD for antagonists was decreased by pretreatment with pertussis toxin from 83 +/- 7 to 56 +/- 5 pM (P less than 0.01); Gpp(NH)p induced a further change in the affinity for the antagonist in membranes from both control and pertussis toxin-treated rats. The change suggested positive cooperativity. The total number of sites was not modified significantly by either pertussis toxin treatment or guanine nucleotides. These results are consistent with a possible reciprocal modulation of the affinity for agonists and antagonists of the cardiac muscarine receptor.

[Evaluation of sympathetic tone in essential hypertension by the clonidine suppression test]. / Valoración del tono simpático en la hipertensión esencial mediante la prueba de supresión por clonidina.

Recent evidences suggest that the sympathetic nervous system plays a major role in the pathogenesis and maintenance of several clinical forms of hypertensive disease. The clonidine suppression test allows us to uncover the subtle changes in neuronal noradrenaline release in essential hypertension. To prove this possibility, we selected 16 patients: 7 borderline hypertensives (BH) (4 males and 3 females), mean age: 24 years; and 9 established hypertensives (EH) (6 males and 3 females), mean age: 25 years. In both groups, the heart rate (HR) and blood pressure (BP) were registered every 30 min and by intravenous catheter plasma catecholamines (PCA) and plasma renin activity (PRA) were measured before and after (180 and 240 min) one oral dosis of clonidine (300 mcg) had been administered. Patients remained in clinostatism for 180 and and orthostatism for 60 min. HR and BP diminished in BH and EH after clonidine during clinostatism in comparison to preclonidine period. PCA also showed reduction in 180 min with respect to the basaline period. PRA did not present change in 180 min in either groups in relation to time O. During orthostatism, HR increased in both groups with respect to the baseline period. BP remained low in relation to baseline time. PCA were increased with respect to preclonidine period. PRA showed a slight tendency to increase in relation to time O in both groups. CAP baseline level are not reliable indexes of the role of the sympathetic tone in maintenance of high BP values in hypertensive disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Guanine nucleotide-induced positive cooperativity in muscarinic-cholinergic antagonist binding.

The effect of guanine nucleotides on the binding of [3H] Quinuclidinyl benzilate to heart muscarinic receptors was studied. It was observed that GTP and Gpp (NH)p increased antagonist binding. Scatchard transformation of the data resulted in curvilinear plots (downward concavity) consistent with positive cooperativity. Graphic analysis for cooperativity indicated that guanine nucleotides: a) increased slightly but consistently the affinity for the antagonist (independent of receptor occupancy) and b) induce positive cooperativity in the binding of [3H]QNB (dependent of receptor occupancy).

[Perioperative management of the diabetic patient in cardiac surgery with extracorporeal circulation]. / Manejo perioperatorio del paciente diabético en cirugía cardíaca con circulación extracorporea.

The hyperglycemia usually observed in patients undergoing heart surgery with extracorporeal circulation (EC) represents a difficult therapeutic problem. We studied the effects of several regimens of insulin therapy on serum glucose (SG) in 24 noninsulin dependent diabetic patients (NIDDs). The patients were randomly divided in five groups; group A received on IV bolus of 10.0-50.0 U/h according to glycosuria; groups B, C, D and E were given a continuous iv insulin infusion of 2.5, 5.0, 7.5 and 10.0 U/h respectively. In 10 non-diabetic patients (NDP) SG levels were also measured, but insulin was not given. A mean of 5.0 l/m2 of body surface of fluids containing 300 g of glucose were administered to all patients during surgery. At the operations SG levels rose progressively soon after the anesthesia was started, reached the highest values during the period of EC, and decreased slowly in blood samples taken after the EC phase and by 24h. This patterns was shown by all groups studied statistically significant lower SG levels, however, were observed in patients of group C, whose values were similar to those seen in the NDP group. Groups D and E had slightly higher SG levels than those of group C. An additional NIDDM patient with advanced chronic renal failure (CRF), had a tendency to hypoglycemia even during the EC period in response to relatively low doses of insulin (2.5 U/h), given by a continuous iv infusion and, although the insulin administration was stopped, his SG levels remained well below the mean values of the other patients for the rest of the operation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Thyroid dysfunction induced by amiodarone]. / Disfunción tiroidea inducida por amiodarona.

Amiodarone (2-n-butyl-3,4-diethylaminoethoxy-3',-diiodobenzoyl-benzofurone ) is a drug widely used for the treatment of cardiac arrhythmias. Due to its high iodine content and structural similarity to thyroxine it produces abnormalities in thyroid hormone metabolism and, in some cases, clinical thyroid dysfunction as well. We report 18 patients, 11 females and 7 males, whose thyroid disease developed during treatment with amiodarone (A). Age ranged from 13 to 64 years. A history of thyroid disease in a first-degree relative was present in five, and three patients had goiter prior to A therapy. Fifteen patients had atrial arrhythmias, and 3 had ventricular arrhythmias. Amiodarone was being given in doses of 200 to 800 mg daily. Thyroid function abnormalities appeared between 1 and 29 months after starting A therapy. Nine patients became clinically and chemically thyrotoxic; three patients developed diffuse thyroid enlargement and had total T4 concentration and FI4I increased with normal T3 and no signs of hyperthyroidism; and the six remaining patients became clinically hypothyroid with low values of total T4 and FTI and raised basal TSH. No relationship between dosages of A or duration of treatment and the appearance or severity of thyroid dysfunction was found. Regression of symptoms occurred in all but two patients with simple goiter between 1 and 8 months after amiodarone was discontinued and appropriate treatment was given. Our observations confirm the potential of A to induce thyroid abnormalities in patients with and without preexistent thyroid disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effect of pertussis toxin on the affinity state for agonists of renal alpha 1- and alpha 2- adrenoceptors.

The effect of pertussis toxin treatment on the guanine nucleotide-induced modulation of the affinity of renal alpha 1- and alpha 2-adrenergic receptors was investigated. Pretreatment of rats with pertussis toxin did not induce any change in the number of or affinity for antagonists of alpha 1- or alpha 2-receptors studied using [3H]prazosin and [3H]yohimbine, respectively. Guanyl-5'-yl imidodiphosphate induced an "up-shift" in the number of alpha 2-adrenergic receptors; this up-shift was not observed for alpha 1-adrenergic receptors. Pertussis toxin treatment decreased the affinity of epinephrine for the [3H]yohimbine-binding sites and reduced the ability of guanine nucleotides to modulate alpha 2-adrenoceptor agonist affinity. The regulation by guanine nucleotides of alpha 1-adrenoceptor affinity for agonists was not altered. These results suggest that the modulation of alpha 1- and alpha 2-adrenoceptors by guanine nucleotides is probably exerted through different molecular entities.

"Pertussis toxin induces tachycardia and impairs the increase in blood pressure produced by alpha 2-adrenergic agonists".

Administration of purified pertussis toxin to rats induced persistent tachycardia, (observed in conscious rats but not after pithing); as little as 0.05 microgram/100 g produced a significant effect. Pertussis toxin-treatment did not affected the pressor response produced in the pithed rats by the alpha 2-adrenergic agonist methoxamine but markedly diminished the pressor effect of the alpha 2-adrenergic agonists clonidine and azepexole. A role of adenylate cyclase inhibition in the action of postsynaptic vascular alpha 2-adrenergic receptors is suggested.

[Pheochromocytoma and catecholamines. Experience in 63 cases studied for 25 years]. / Feocromocitoma y catecolaminas. Experiencia en 63 casos estudiados durante 25 años.

The usefulness of fluorimetric techniques in the diagnosis of pheochromocytoma was investigated. In the 63 cases studied during 25 years by measuring simultaneously various aminergic parameters, including plasma catecholamines and urinary adrenaline (A), noradrenaline (N) and vanilmandelic acid (VMA), we were able to establish the diagnosis of pheochromocytoma in all cases. Adrenaline excretion was found to be higher in patients with tumors located on the adrenal region, whereas N excretion was predominantly increased in patients with extra-adrenal tumors. In patients having tumors smaller than 50 g, A + N excretion was higher and VMA was lower than in those whose tumors were heavier; therefore in cases with small tumors the ratio VMA/A + N was lower than in those with larger tumors. It is concluded that simultaneous measurements of PC, A, N and VMA allow the diagnosis to be made in the most patients with this tumor. On the other hand, the predominant increase in A excretion is suggestive of adrenal pheochromocytoma.

Effect of pertussis vaccine on alpha-adrenoceptors of the circulatory system of the rat.

Administration of pertussis vaccine to rats markedly diminished the sensitivity of their vascular alpha 2-adrenoceptors as evidenced by shifts to the right and decreased maximal pressor responses to clonidine and azepexole in pithed rats. No effect was observed on the sensitivity of alpha 1-adrenoceptors as evidenced by the dose-response curve to methoxamine. A slight persistent tachycardia was also produced by the vaccine. A model to explain the effects of the vaccine on the vascular system of the rat is proposed.

[Effect of inhibition of converting enzyme by captopril on arterial pressure, renin and aldosterone in essential hypertension]. / El efecto de la inhibición de la enzima convertidora con captopril sobre la presión arterial, renina y aldosterona en el hipertenso esencial.

The response of arterial blood pressure, plasma renin activity (PRA) and plasma (PA) or urinary aldosterone (UA) concentrations to the administration of captopril, was studied in patients with established essential hypertension. Captopril was effective in lowering significantly the blood pressure (189.4/111.2 +/- 23.9/9.7 to 163.4/98.1 +/- 20.7/8.6 mmHg. mean +/- SD, p less than 0.01/0.001). Normal arterial blood pressure values (140.4/86.5 +/- 20.7/10.8 mmHg, were achieved by the addition of hydrochlorothiazide. Captopril administration was followed by a decrease in PA and in UA and an increase in PRA, suggesting the inhibition of angiotensin II formation. Captopril attenuated hypokalemia and hyperaldosteronism produced by the simultaneous administration of hydrochlorothiazide.