No evidence of increased risk for certain highly atherogenic lipoprotein phenotypes in HIV-infected patients.

BACKGROUND: There is a need to assess whether human immunodeficiency virus (HIV)-infected patients are more likely than noninfected individuals to have any of the specific lipoprotein combination profiles identified as the best predictors of future cardiovascular disease in the general population. METHODS: One hundred five infected patients, randomly selected from a Mexican HIV clinic, and 105 age- and gender-matched noninfected community volunteers, were enrolled to study the prevalence of each of three highly atherogenic lipoprotein phenotypes [high apolipoprotein (Apo)B/ApoA-I ratio, hypertriglyceridemia with high ApoB and hypoalphalipoproteinemia with high ApoB], and the relationship between time of exposure to antiretroviral therapy (ART) drug class and lipid changes. RESULTS: The highly atherogenic lipoprotein phenotypes were similarly frequent in both groups. There was a nonsignificant increased risk of dyslipidemia with longer exposure to any of the ART drug classes, although this hazard seems to be greater in patients with central fat accumulation. CONCLUSIONS: No evidence of increased risk for certain highly atherogenic lipoprotein phenotypes in HIV-infected patients was found. More than one pathogenic mechanism for ART-associated dyslipidemia is postulated.

Human immunodeficiency virus-infected subjects have no altered myocardial perfusion.

We assessed myocardial perfusion (blinded interpretation of a single-photon emission computed tomography) and known risk factors for atherosclerosis in 105 randomly selected human immunodeficiency virus (HIV)-infected patients in a clinic in Mexico City and in a community sample of 105 age and gender-matched infection-free subjects. An abnormal scan was obtained in 4.8% of the infected and in 7.6% of the non-infected subjects. Severity of scintigraphic abnormalities was similar in both groups. In these Mexican HIV-infected patients, despite a long time of infection and of exposure to combined antiretroviral therapy and to other classical risk factors for atherosclerosis, there was no evidence of increased risk for abnormal myocardial perfusion. Dissimilar magnitude in the hazard of coronary heart disease may occur among infected populations with different frequencies of traditional predisposing factors for cardiovascular illness.

Arginine-vasopressin mediates central and peripheral glucose regulation in response to carotid body receptor stimulation with Na-cyanide.

Hypoxic stimulation of the carotid body receptors (CBR) results in a rapid hyperglycemia with an increase in brain glucose retention. Previous work indicates that neurohypophysectomy inhibits this hyperglycemic response. Here, we show that systemic arginine vasopressin (AVP) induced a transient, but significant, increase in blood glucose levels and increased brain glucose retention, a response similar to that observed after CBR stimulation. Comparable results were obtained after intracerebral infusion of AVP. Systemic AVP-induced changes were maintained in hypophysectomized rats but were not observed after adrenalectomy. Glycemic changes after CBR stimulation were inhibited by pharmacological blockage of AVP V1a receptors with a V1a-selective receptor antagonist ([beta-Mercapto-beta,beta-cyclopentamethylenepropionyl1,O-me-Tyr2, Arg8]-vasopressin). Importantly, local application of micro-doses of this antagonist to the liver was sufficient to abolish the hyperglycemic response after CBR stimulation. These results suggest that AVP is a mediator of the hyperglycemic reflex and cerebral glucose retention following CBR stimulation. We propose that hepatic activation of AVP V1a receptors is essential for this hyperglycemic response.

Applicability of the National Cholesterol Education Program III (NCEP-III) guidelines for treatment of dyslipidemia in a non-Caucasian population: a Mexican nation-wide survey.

We assessed the impact of the NCEP-III recommendations in a population-based, nation-wide Mexican survey. Information was obtained from 15,607 subjects aged 20 to 69 years. In this report, only samples obtained after a 9 to 12 hours fast are included (2,201 cases). A cardiovascular risk equivalent was found in 10.5% and > or = 2 risk factors were present in 41.7% of the population. In 10% of cases, the LDL-C concentration was high enough to be an indication for a lipid-lowering drug (> 160 mg/dL), independent of the presence of risk factors. A quarter of the population was eligible for some form of treatment (lifestyle modifications in 15.9%, drug therapy in an additional 11.7%). Among cases with > or = 2 risk factors, a small percentage (1.8%) were identified as having a 10 year-risk > 20% and 86.3% were considered as having a 10 year-risk < 10%. The majority of the metabolic syndrome cases (84%) were identified as low-risk subjects. As a result, only 17.6% of them qualified for drug-based LDL-C lowering. Our data helps to estimate of the magnitude of the burden imposed on the Mexican health system, of lowering LDL-C for cardiovascular prevention. If we apply our results to the 2,000 Mexican population census more than 5.8 million cases nationwide may require LDL lowering drug therapy following the NCEP-III criteria.

Applicability of the National Cholesterol Education Program III (NCEP-III) Guidelines for treatment of dyslipidemia in a non-Caucasian population: A Mexican Nation-Wide Survey / Aplicabilidad del III Programa Nacional de Educación en Colesterol (NCEP-III). Guías para el tratamiento de la dislipidemia en una población no caucásica: Un estudio en toda la nación mexicana

We assessed the impact of the NCEP-III recommendations in a population-based, nation-wide Mexican survey. Information was obtained from 15,607 subjects aged 20 to 69 years. In this report, only samples obtained after a 9 to 12 hours fast are included (2,201 cases). A cardiovascular risk equivalent was found in 10.5% and > 2 risk factors were present in 41.7% of the population. In 10% of cases, the LDL-C concentration was high enough to be an indication for a lipid-lowering drug (> 160 mg/dL), independent of the presence of risk factors. A quarter of the population was eligible for some form of treatment (lifestyle modifications in 15.9%, drug therapy in an additional 11.7%). Among cases with > 2 risk factors, a small percentage (1.8%) were identified as having a 10 year-risk > 20% and 86.3% were considered as having alO year-risk < 10%. The majority of the metabolic syndrome cases (84%) were identified as low-risk subjects. As a result, only 17.6% of them qualified for drug-based LDL-C lowering. Our data helps to estimate of the magnitude of the burden imposed on the Mexican health system, of lowering LDL-C for cardiovascular prevention. If we apply our results to the 2,000 Mexican population census more than 5.8 million cases nationwide may require LDL lowering drug therapy following the NCEP-III criteria.

Evaluamos el impacto de las recomendaciones del Programa Nacional de Educación en Colesterol (NCEP-III) en muestra poblacíonal. La información proviene de 2,201 sujetos de 20 a 69 años cuyas muestras se obtuvieron después de un ayuno de 9 a 12 horas. Una condición con riesgo cardiovascular equivalente al de la cardiopatía isquémica se encontró en 10.5%; > 2 factores de riesgo se encontraron en 41.7%. El colesterol LDL (LDL-C) fue suficientemente alto (> 160 mg/dL) para indicarse tratamiento hipolipemiante con medicamentos, en ausencia de otros factores de riesgo en 10% de los participantes. El 25% de la población calificó para recibir tratamiento hipolipemiante (cambios del estilo de vida 15.9% y tratamiento farmacológico en 11.7%). En casos con > 2 factores de riesgo, un pequeño porcentaje (1.8%) fue identificado con riesgo mayor a > 20% de tener un evento cardiovascular a 10 años; 86.3% fue identificado con bajo riesgo (< 10% a 10 años). La mayoría de los casos con síndrome metabólíco (84%) fueron identificados en el grupo de bajo riesgo. Como resultado, sólo 17.6% de ellos calificó para disminuir su LDL-C con medicamentos. Nuestros datos demuestran el reto que representa la prevención de complicaciones cardiovasculares por medio de la reducción de la concentración del LDL-C. Extrapolando nuestros datos al censo 2000, más de 5.8 millones de mexicanos califican para recibir tratamiento farmacológico de acuerdo con los criterios del NCEP-III.

High prevalence of metabolic syndrome in Mexico.

BACKGROUND: Our objective was to describe the prevalence of the metabolic syndrome using World Health Organization (WHO) and National Cholesterol Education Program (NCEP-III) definitions in a population-based survey. METHODS: We performed an analysis of data from a Mexican nationwide, population-based study. The population was composed of 2,158 men and women aged 20-69 years sampled after a 9-12 h fasting period. Prevalence of the metabolic syndrome as defined by the NCEP-III definition and WHO criteria was estimated and case characteristics were assessed. RESULTS: Age-adjusted prevalence was 13.61% for WHO criteria and 26.6% for the NCEP-III definition. Prevalence was 9.2 and 21.4%, respectively, in subjects without diabetes. Thirty five percent of affected cases were <40 years of age. In addition to criteria used for diagnosis, ca. 90% were either overweight or obese. In cases detected using WHO criteria, antihypertensive treatment or blood pressure reading >140/90 was found in 61.8%. The proportion of subjects who qualified for hypolipemiant treatment was lower: lifestyle modifications were needed in 42.1% and drug therapy was required in 18.9%. The same trends were found for cases detected using the NCEP definition. CONCLUSIONS: Prevalence of the metabolic syndrome in Mexico is high. A large proportion of affected cases qualify for preventive actions for complications of the metabolic syndrome (i.e., weight loss, antihypertensive or hypolipemiant treatment). These results provide data for planning therapeutic programs for Mexican patients with the metabolic syndrome.

[Plasma homocysteine concentrations in Mexican patients with ischemic heart disease]. / Concentraciones de homocisteína plasmática en pacientes mexicanos con cardiopatía isquémica.

AIMS: Several risk factors for the development of coronary atherosclerosis (CA) have been identified. These included hyperlipidemia, hypertension, smoking and diabetes mellitus. As well as elevated plasma homocysteine (tHcys) levels, is considered an independent risk factor for CA in some American and Europeans studies, but its association are scare in Latin-American population. We therefore conducted a case-control study to explore this issue in Mexican population. PATIENTS AND METHOD: Eighty eight patients with scintigraphic evidence of CAD or history of myocardial infarction compared with a control group of 96 individuals were analyzed. tHcys were measured in all subject's serum samples. Conventional risk factors were also analyzed. RESULTS: A high prevalence of hyperhomocystinemia with no significant difference between the 2 groups was found. The mean concentration of tHcys was 13.9 micromol/L (SD +/- 6.9) in the CA group; and 14.8 micromol/L (SD +/- 7.3) in the control group. We did not obtain a statistical difference on tHcys concentration between patients with and without others risk factors, like diabetes mellitus, hyperlipidemia, hypertension, smoking and obesity. CONCLUSION: Ours results shown a high prevalence of hyperhomocystinemia (> 12 micromol/L) in Mexican people. However these high levels were not associated with evidence of CA. More studies in our population are warranted to clarify the possible influence of homocysteine on coronary atherosclerosis.

Induction of brain glucose uptake by a factor secreted into cerebrospinal fluid.

It is well established that the carotid body receptors (CBR), at the bifurcation of the carotid artery, inform the brain of changes in the concentration of CO(2) and O(2) in arterial blood. More recent work suggests that these receptors are also extremely sensitive to blood glucose levels suggesting that they may play an important role as sensors of blood components important for brain energy metabolism. Much less is known about changes in brain glucose metabolism in response to CBR activation. Here we show that 2-8 min after local injection of sodium cyanide (NaCN) into the CBR or after electrical stimulation of the carotid sinus nerve in dogs and rats, brain glucose uptake increased fourfold. Cerebrospinal fluids (CSF) transferred from dogs, 2-8 min after CBR stimulation, into the cisterna magna of non-stimulated dogs or rats induced a similar increase in brain glucose uptake. CSF from stimulated dogs was also active when injected intravenously in anesthetized or awake rats. The activity was destroyed when the stimulated CSF was heated to 100 degrees C or treated with trypsin. We conclude that a peptide important for brain glucose regulation appears in the CSF shortly after CBR stimulation.

Prevalence and characteristics of early-onset type 2 diabetes in Mexico.

OBJECTIVE: To investigate the prevalence and characteristics of patients with type 2 diabetes diagnosed before the age of 40 years (early-onset disease) in a nationwide, population-based study. METHODS: Using a multistage sampling procedure, we enrolled a representative sample of Mexican urban adults aged 20 to 69 years. Weight, height, blood pressure, and plasma levels of glucose, insulin, and other metabolic parameters were measured in all subjects. RESULTS: We identified 993 subjects with type 2 diabetes, including 143 subjects aged 20 to 39 years (14% of those with diabetes). Subjects with early-onset diabetes had a greater prevalence of obesity and higher plasma insulin and lipid levels than did age-matched controls, and a greater prevalence of high-density lipoprotein cholesterol levels <35 mg/dL and severe hypertriglyceridemia than did older subjects with diabetes. Those (n = 32) with a normal body mass index (20 to 25 kg/m(2)) tended to have insulin deficiency as the main abnormality, whereas the "metabolic syndrome" characterized the remaining 111 subjects with early-onset diabetes. CONCLUSION: Most patients with early-onset type 2 diabetes in Mexico are obese or overweight, suggesting that obesity treatment and prevention programs may be effective in reducing the prevalence of this disease.

Características de los casos con dislipidemias mixtas en un estudio de población: resultados de la Encuesta Nacional de Enfermedades Crónicas / Characteristics of mixed hyperlipidemia cases in a population-based study: results from the Mexican National Survey of Chronic Diseases

Objetivo. Describir las características de los pacientes con hiperlipidemia mixta de acuerdo con los datos derivados de la Encuesta Nacional de Enfermedades Crónicas. Material y métodos. Se realizó una entrevista en 1993, en 417 ciudades del país, y se midieron las concentraciones sanguíneas de lípidos séricos, glucosa e insulina en 2 206 casos en un estudio poblacional. La diferencia entre los pacientes con dislipidemias mixtas y el resto de la población se estableció utilizando análisis de varianza o la prueba de ji cuadrada. Resultados. La hiperlipidemia mixta se encontró en 282 casos (12.8 por ciento). Los individuos afectados tenían 42.7 ± 12.6 años. El 56 por ciento eran hombres; 46.4 por ciento tenían un colesterol HDL < 0.9 mmol/l. La presencia de otros factores de riesgo fue común. La prevalencia de las hiperlipidemias mixtas fue alta aun en adultos jóvenes. Por medio de un modelo de regresión logística fue posible identificar la obesidad, la edad, el género, la región del país en donde residía el sujeto, la presencia de diabetes o de hipertensión arterial y la concentración de insulina de ayuno >21 mU/ml como anormalidades asociadas a las dislipidemias mixtas. Conclusiones. La dislipidemia mixta es muy frecuente en adultos mexicanos. Se observa predominantemente en hombres mayores de 30 años y los casos tienen otros factores de riesgo cardiovascular. Los datos sugieren que el síndrome metabólico participa en la génesis de la dislipidemia mixta

Apolipoprotein B and A-I distribution in Mexican urban adults: results of a nationwide survey.

The apolipoprotein (apo) B and A-I distribution found in a survey performed in 417 Mexican cities is described. Information was obtained from 15,607 subjects aged 20 to 69 years. In this report, only samples obtained after a 9- to 12-hour fast were included (1,674 cases, 652 men and 1,022 women). The population is representative of the Mexican urban adults. Mean lipid concentrations were: cholesterol,182.7 mg/dL; triglycerides, 213 mg/dL; high-density lipoprotein (HDL) cholesterol, 38.3 mg/dL; and low-density lipoprotein (LDL) cholesterol, 116 mg/dL. The mean concentration of apo B was 77.8 +/- 25.9 mg/dL and 71 +/- 22.8 in men and women, respectively. A continuous increase of apo B was observed as subjects got older. A tendency to decrease after age 60 was observed in men, but not in women. The body mass index (BMI) is a major determinant for the apo B concentrations. The 90th percentile of the apo B concentration identifies a similar proportion of abnormal subjects than the LDL cholesterol concentration of 160 mg/dL. The 120 mg/dL concentration, upper normal limit level used in other populations, identified as abnormal only 3.8% of the cases. Regardless of the lipid abnormality, an apo B above the 90th percentile was associated with higher levels of glucose, cholesterol, triglycerides, and non-HDL cholesterol, despite a similar age and BMI. The overall mean concentration of apo A-I was 122.3 +/- 31 mg/dL and 129 +/- 34 in men and women, respectively. In conclusion, our data show that the apo B and apo A-I concentrations in Mexican urban adults are lower compared with the levels reported in other ethnic groups. Previously used reference ranges are not useful in the population report herein. These observations strengthen the need for obtaining data in population-based studies worldwide.

[Characteristics of mixed hyperlipidemia cases in a population-based study: results from the Mexican National Survey of Chronic Diseases]. / Características de los casos con dislipidemias mixtas en un estudio de población: resultados de la Encuesta Nacional de Enfermedades Crónicas.

OBJECTIVE: To describe the characteristics of mixed hyperlipidemia cases, using data derived from the Encuesta Nacional de Enfermedades Crónicas (Mexican National Survey of Chronic Diseases, ENEC). MATERIAL AND METHODS: The ENEC was conducted in 1993, in 417 Mexican cities. Blood measurements of lipids, glucose, and insulin were obtained from 2206 cases. Differences between dyslipidemia patients and non cases were obtained using analysis of variance or the chi-squared test. RESULTS: Mixed hyperlipidemia was diagnosed in 282 subjects (12.8%). Cases were 42.7+/-12.6 years old. Fifty six percent were males and 46.4% had HDL cholesterol levels < 0.9 mmol/l. Other cardiovascular risk factors were also present. The prevalence of mixed hyperlipidemia was high even among young adults. A logistic regression model showed that obesity, age, male gender, residence in some regions of Mexico, diabetes, arterial hypertension, and fasting insulin levels >21 mU/ml, were factors associated with mixed hyperlipidemia. CONCLUSIONS: Mixed hyperlipidemia is a very common condition in Mexican adults. It is more common in males older than 30 years, with additional cardiovascular risk factors. Study findings suggest that the metabolic syndrome plays a role in the pathogenesis of this disorder.

Comparative accuracy of glucose monitors

Background. Self-monitoring of blood glucose levels has become an important instrument for the management of patients with diabetes mellitus. Both patients and physicians expect that monitors will provide reliable results. Numerous environmental, physiologic, and operational factors can affects system performance, yielding results that are inaccurate or unpredictable. Methods. This study examined the effect of one factor -high altitude- on the performance of seven blood glucose monitoring systems. The following monitors were compared. two One Touch II; two One Touch Basic; two Reflolux II (Accu-Chec in the USA); two Glucometer 3; one Glucometer 2, and one Accutrend Alpha. Double blood glucose level values were compared with a cotrolled reference laboratory test values, which was unknown to the investigator until the end of the study because the study was double blind. Blood glucose values were obtained using each of the monitors in 200 patients; 150 with diabetes mellitus, and 50 healthy subjects. Results. The One Touch monitors were the only monitors that reported adjusted straight lines (Y0a+bX) that were very similar for all three techniques. In addition, these adjusted straight lines are those closest to the ideal line, Y=X. These same monitors were the only ones that did not reject the null hypothesis Ho: a=0. The relative deviation index at the 20 percent level was less than 3.5 percent for the One Touch II and One Touch Basic monitors; for the rest of the monitors the index was over 14 percent. The clinically accepted EGA region was similar for all study monitors. Conclusions. In conclusion, the One Touch II and One touch Basic Monitors showed greater accuracy in comparison to the other devices. The evaluation of the clinically acceptable region shows practical reliability for all of the monitor used

Alteraciones metabólicas en sobrevivientes de infarto miocardico / Metabolic changes in myocardial infarction survivors

Existen múltiples evidencias que establecen la importancia de las lipoproteínas como factores de riesgo en la génesis de la ateroesclerosis. Los estudios epidemiológicos realizados en paises desarrollados han revelado que aproximadamente un tercio de los sobrevivientes de infarto miocárdico menores de 60 años tienen hiperlipidemia. El estrés que ocurre en las primeras horas a partir del inicio del infarto ocasiona ciertos cambios metabólicos, principalmente una disminución del colesterol total, del colesterol de las lipoproteínas de baja densidad y un incremento generalmente ligero de la glucemia. Con el objeto de establecer la prevalencia y magnitud de los trastornos del metabolismo de las lipoproteínas que ocurren en sobrevivientes de infarto miocárdico residentes en la ciudad de México se realizó un estudio prospectivo en 106 pacientes que fueron internados consecutivamente en la unidad de cuidados coronarios del Instituto Nacional de Cardiología con el diagnóstico comprobado de infarto miocárdico agudo. Se incluyeron únicamente los pacientes menores de 60 años que se encontraban dentro de las primeras 72 del inicio del cuadro clínico y en esta etapa (fase aguda) se obtuvo el perfil de riesgo coronario y una muestra de sangre. En 81 de los 106 pacientes iniciales se contó con otra muestra de sangre tres meses después de ocurrido el infarto (muestra crónica). Al comparar los resultados de las muestras aguda y crónica de estos 81 pacientes se observaron diferencia importantes de los parámetros lipídicos. El valor medio para el colesterol total en la muestra aguda fue de 225 mg/dl., el valor correspondiente para la muestra crónica fue de 240.5 mg/dl (p<0.005). Se observaron cambios similares, altamente significativos para la fracción asociada a las lipoproteínas de baja densidad...