Compliance with a WHO guideline for cardiovascular disease prevention. A population based cross-sectional study in Argentina

INTRODUCTION

Current recommendations for cardiovascular disease (CVD) prevention are guided CVD risk classification. This study aims to analyze the level of compliance with pharmacological and non-pharmacological recommendations outlined in the World Health Organization (WHO) CVD prevention clinical practice guideline within the general population of two cities in Argentina.

METHODS

We analyzed the compliance with preventive recommendations from the WHO 2007 Guidelines for Management of Cardiovascular Risk in two cities of Argentina participating in the CESCAS population-based study in the Southern Cone of Latin America.

RESULTS

3990 participants were included. Considering the WHO recommendations, the use of antiplatelet medication was 5.6% (95% CI 3.5, 8.9) in primary prevention and 20.5% (95%= CI 16.0, 25.9) in secondary prevention. Regarding lipid-lowering medication, it was 6.7% (CI 95%= 4.4, 10.1) and 15.4% (CI 95%= 11.6, 20.1), respectively. As per non-pharmacological recommendations in the general population: low intake of fruit and vegetables was 78.4% (CI 95%= 76.8, 79.9); low physical activity was 26.9% (CI 95%= 25.3, 28.5), current cigarette smoking was 28.3% (CI 95%= 26.6, 30.0), overweight/obesity was 73.9% (CI 95%= 72.3, 75.6), and excessive alcohol intake was 2.6% (CI 95%= 2.1, 3.4).

CONCLUSIONS

It was observed a significantly low compliance with pharmacological and non-pharmacological recommendations for CVD prevention in the general population of two cities in Argentina. Urgent efforts are needed to improve compliance to cardiovascular preventive recommendations promoted by CPG, especially in Low- and Middle- Income Countries.

Dietary patterns and blood pressure in Southern Cone of Latin America

BACKGROUND AND AIMS

in the Southern Cone of Latin America, previous studies have shown that blood hypertension is one of the most significant risk factor for cardiovascular disease, and diet plays a fundamental role. We analyzed the cross-sectional relationship between dietary patterns (DP) and blood pressure values in people involved in the CESCAS I Study.

METHODS AND RESULTS

the participants (n = 4626) were derived from randomly selected samples in 4 cities (Bariloche and Marcos Paz, Argentina; Temuco, Chile; and Pando-Barros Blancos, Uruguay). To define DP, a food-frequency questionnaire was applied and principal component analysis was performed. Blood pressure was determined according to standardized guidelines. A multivariate regression model was developed to determine the association between each DP and blood pressure values, according to the quartile (Q) of adherence to DP. Two predominant DP were detected, Prudent (PDP, higher consumption of fruits, vegetables, legumes, whole grains, fish, seafood and nuts) and Western (WDP, higher consumption of red and processed meats, dressings, sweets, snacks and refined grains). A significant inverse association was found between adherence to PDP and systolic and diastolic blood pressure (-1.85 and -1.29 mmHg for Q4 vs Q1, respectively). Adherence to WDP was positively associated with systolic blood pressure (2.09 mmHg for Q4 vs Q1).

CONCLUSION

the WDP detected in the studied population is positively associated with higher levels of blood pressure, while greater adherence to healthy DP has a positive impact on blood pressure.

Attributes of the food and physical activity built environments from the Southern Cone of Latin America

Previous studies have shown the influence of the physical and social environments on the development of obesity and non-communicable diseases (NCD). An obesogenic environment promotes higher dietary energy intakes and sedentary behaviors while limiting opportunities or incentives for active living. This paper presents a dataset with key attributes of the food and physical activity built environment, including green spaces, quality of streets and sidewalks, and different types of food retail outlets in four cities of the Southern Cone of Latin America. A total of 139 representative neighborhoods randomly selected from: Marcos Paz and Bariloche (Argentina), Temuco (Chile) and Canelones-Barros Blancos (Uruguay) were evaluated, where standardized community walks were conducted for direct observation of the built environment. This dataset will contribute valuable data to the evaluation of obesogenic environments in the region, and could be linked to additional ecological information about risk factors for NCDs and socio-economic features from other sources. Understanding environmental influences on cardiovascular risk factors and individual habits may help explain NCD outcomes and plan urban policies.

Association between drinking patterns and cardiovascular risk: a population-based study in the Southern Cone of Latin America

BACKGROUND

Using data from general adult population, this study aims to describe epidemiology of alcohol consumption patterns and their association with cardiovascular risk.

METHODS

CESCAS I is a population-based study from four mid-sized cities in Argentina, Chile and Uruguay. Associations between diabetes, hypertension, dyslipidemia, cardiovascular disease (CVD) risk and history of CVD and drinking patterns were assessed using crude prevalence odds ratios (ORs) and adjusted OR.

RESULTS

A total of 37.2% of the studied population never drank and 18.3% reported to be former drinkers. Among current drinkers, moderate drinking was the most frequent pattern (24.2%). For women with light and moderate consumption, the odds of having >20% CVD risk was ~40% lower than that of never drinkers. The odds of having a history of CVD was 50% lower in those with moderate consumption. For men with heavy consumption, the odds of having >20% CVD risk was about twice as high as for never drinkers.

CONCLUSIONS

A harmful association was observed between heavy drinking and having >20% CVD risk for men. However, for women, an apparently protective association was observed between light and moderate drinking and having >20% CVD risk and between moderate drinking and having a history of CVD.

Suicidal ideation is associated with cardiovascular disease in a large, urban cohort of adults in the Southern Cone of Latin America

INTRODUCTION

To examine the relationship between suicidal ideation (SI) and cardiovascular disease (CVD) in the general adult population of four cities in the Southern Cone of Latin America (Argentina, Uruguay, Chile) and the role that depression, stressful life events (SLEs) and physical functional impairment may play in this association.

METHODS

A population-based cross-sectional study was conducted among 7524 adults between 35 and 74 years old, randomly selected. History of CVD included acute myocardial infarction, stroke and central or peripheral revascularization. SI in the past two weeks was measured using the last item of the Patient Health Questionnaire (PHQ-9), quality of life was assessed with the 12-item Short Form Survey (SF-12), and having experience of a SLE was determined by asking participants whether they had experienced at least one of a list of events in the past year. Multiple logistic regression was used to examine the association between SI and CVD overall and by sex.

RESULTS

The prevalence of SI was 8.3% (95% CI = 7.5, 9.0) and twice as high among women than men (11.1% vs. 5.1%). History of CVD was associated with almost twice the odds of SI (OR = 1.9, 95% CI = 1.5, 2.4). This association remained strong and significant after adjusting for potential confounders (OR = 1.8, 95% CI = 1.2, 2.7). Three additional models were tested to further adjust for depression severity, functional impairment, and SLEs separately. Adjustment for depression severity yielded no association between CVD and SI (OR = 1.1, 95% CI = 0.6, 1.7), adjustment for functional impairment yielded a marginal statistically significant association (OR = 1.5; 95% CI = 1.0, 2.4) and adjustment for SLE didn't modify either the magnitude or the statistical significance of the association.

CONCLUSIONS

There is a significant association between SI and CVD, particularly among women, which may be driven, at least in part, by depression and physical functional impairment.

Estimating prevalence of chronic obstructive pulmonary disease in the Southern Cone of Latin America: how different spirometric criteria may affect disease burden and health policies

Background

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide. The study aimed to determine and compare the prevalence of COPD in the general population aged 45-74 years old according to fixed ratio and lower limit of normal (LLN) thresholds in four cities in the Southern Cone of Latin America.

Methods

The Pulmonary Risk in South America (PRISA) study used a 4-stage stratified sampling method to select 5814 participants from 4 cities in the Southern Cone of Latin America (Bariloche and Marcos Paz, Argentina; Temuco, Chile; and Pando-Barros Blancos, Uruguay). Data on demographic information, medical history, risk factors, pre-bronchodilator and post-bronchodilator spirometry were obtained using a standard protocol. According to GOLD, COPD was defined as a post-bronchodilator ratio of forced expiratory volume in one second (FEV1) over forced vital capacity (FVC) less than 70%. The LLN threshold was defined as the lower fifth percentile for predicted FEV1/FVC, and was evaluated as an alternative COPD definition.

Results

Overall COPD prevalence was 9.3% (95% CI 8.4, 10.2%), and men had a higher prevalence [11.8% (95% CI 10.3, 13.3%)] than women [7.3% (95% CI 6.2, 8.3%)] with the fixed ratio. Overall COPD prevalence using LLN was 4.7% (95% CI 4.1, 5.3%), higher in men: 5.8% (95% CI 4.7, 6.8%) than women: 3.9% (95% CI 3.1, 4.7%). COPD prevalence was significantly higher among those who were older, had <high-school education and lower body-mass index, were cigarette smokers, and had self-reported history of asthma and tuberculosis.

Conclusions

First, COPD and its risk factors are highly prevalent in the general population of Argentina, Chile, and Uruguay. Second, the prevalence of COPD by LLN criterion was significantly lower with lesser degrees of severity compared to fixed ratio of FEV1/FVC. Implementing LLN criterion instead of fixed ratio of FEV1/FVC may reduce the risk of over-diagnosis of COPD, although further prognostic studies of COPD adverse outcomes should be conducted using both definitions. Third, these data suggest that national efforts on the prevention, treatment, and control of COPD should be a public health priority in the Southern Cone of Latin America.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0537-9) contains supplementary material, which is available to authorized users.

Prevalence, awareness, treatment and control of diabetes and impaired fasting glucose in the Southern Cone of Latin America

AIMS

To determine the prevalence, treatment and control of diabetes mellitus (DM) and impaired fasting glucose (IFG) as well as associated factors in the adult population of four cities of the Southern Cone of Latin America (SCLA).

METHODS

This is a cross-sectional population-based study that included 7407 adults between 35 and 74 years old in four cities of the SCLA: Temuco (Chile), Marcos Paz and Bariloche (Argentina), and Pando-Barros Blancos (Uruguay). DM was defined as fasting plasma glucose ≥126 mg/dL or self-reported history of diabetes. Awareness, treatment, and control of DM were defined as subjects self-reporting a DM previous diagnosis, the use of a prescription medication or nonpharmacological intervention for DM, and fasting plasma glucose <126 mg/dl, respectively.

RESULTS

Prevalence of DM varied among cities, between 8.4% in Bariloche and 14.3% in Temuco. Prevalence of IFG varied at different sites, from 3.5% in Barros Blancos to 6.8% in Marcos Paz. Of the total number of people with diabetes, 20% were newly diagnosed at the time of the study. Overall, 79.8% of patients with diabetes were aware of their condition. The treatment and control rate were 58.8% and 46.2%, respectively. Older age, family history of diabetes, lower educational attainment, overweight, obesity, central obesity, low physical activity, hypertension, hypercholesterolemia and hypertriglyceridemia were all significantly associated with an increased risk of diabetes.

CONCLUSIONS

The prevalence of DM and IFG in the adult population of the SCLA is high and varies among cities. These conditions represent a public health challenge since the rates of awareness, treatment, and control are still low.

Collecting Evidence to Inform Salt Reduction Policies in Argentina: Identifying Sources of Sodium Intake in Adults from a Population-Based Sample

The maximum content of sodium in selected processed foods (PF) in Argentina was limited by a law enacted in 2013. Data about intake of these and other foods are necessary for policy planning, implementation, evaluation, and monitoring. We examined data from the CESCAS I population-based cohort study to assess the main dietary sources among PF and frequency of discretionary salt use by sex, age, and education attainment, before full implementation of the regulations in 2015. We used a validated 34-item FFQ (Food Frequency Questionnaire) to assess PF intake and discretional salt use. Among 2127 adults in two Argentinean cities, aged 35-76 years, mean salt intake from selected PFs was 4.7 g/day, higher among male and low education subgroups. Categories of foods with regulated maximum limits provided near half of the sodium intake from PFs. Use of salt (always/often) at the table and during cooking was reported by 9% and 73% of the population, respectively, with higher proportions among young people. Reducing salt consumption to the target of 5 g/day may require adjustments to the current regulation (reducing targets, including other food categories), as well as reinforcing strategies such as education campaigns, labeling, and voluntary agreement with bakeries.

Drug-induced liver injury 2017: the diagnosis is not easy but always to keep in mind

A drug-induced liver injury (DILI) is defined as a liver injury caused by exposure to a drug or a non-infectious toxic agent with a variable degree of organ dysfunction. A better understanding of DILI epidemiology has been obtained in recent years with the institution of international registries in the United States and Europe. Despite the advances in the understanding and characterization of the phenomenon, DILI remains an exclusion diagnosis so, probability scores and the analysis of literature reports are useful tools in dealing with a suspected DILI. Idiosyncratic DILI can be considered a relatively rare event but it is one of the leading causes of acute liver failure. Thus, proper management is essential to avoid serious consequences. Here, we present an updated review of diagnostic and classification criteria of DILI. Prognostic tools, and principles of management and therapy have also been briefly discussed.

Prevalence, Patterns, and Correlates of Physical Activity Among the Adult Population in Latin America: Cross-Sectional Results from the CESCAS I Study

BACKGROUND

Few data are available on population level regarding domain-specific correlates of physical activity (PA) in Latin America.

OBJECTIVE

The aim of this study was to examine the relationships among PA patterns and their main sociodemographic determinants and cardiovascular risk factors in the Southern Cone of Latin America.

METHODS

CESCAS I is a population-based prospective cohort study with a 4-stage stratified sampling of a general population of 7,524 adults aged 35 to 74 years from 4 midsized cities in Argentina, Chile, and Uruguay. PA was assessed using the transcultural adaptation of the International Physical Activity Questionnaire long form. The questionnaire asked about frequency (days per week) and duration (minutes per day) of moderate and vigorous intensity activities in 3 different domains: work, leisure time, and active transportation (walking and bicycling). PA levels of ≥600 metabolic equivalent tasks (MET) minutes per week was considered sufficiently active. Odds ratios for associations of sufficiently active status with sociodemographic determinants and cardiovascular risk factors were obtained using multivariable-adjusted logistic regression models.

CONCLUSIONS

Almost 65%) of the participants reported ≥600 MET minutes per week. The lowest prevalence of sufficiently active individuals was seen in Temuco, Chile (58.0%), among women (58.7%), older individuals (55.4%), those with higher educational level (61.6%), and homemakers (53.4%). Approximately 22.8% of the population reported no PA. In multivariable analysis, PA levels were lower among women, individuals who were older, obese, university educated, with clerical work, retired/unemployed or homemakers, and those with physical limitations. Future interventions to increase PA levels in the Southern Cone of Latin America must take into account disparities by gender and socioeconomic status. The promotion of PA during leisure time in women--unemployed and homemakers--and of active transportation for those performing office or clerical work should be a priority in this population.

Prevalence, Awareness, Treatment, and Control of Hypertension in the Southern Cone of Latin America

BACKGROUND

Hypertension is the leading global preventable risk factor for premature death. While hypertension prevalence has been declining in high-income countries, it has increased continuously in low- and middle-income countries.

METHODS

We conducted a cross-sectional survey in 7,524 women and men aged 35-74 years from randomly selected samples in 4 cities (Bariloche and Marcos Paz, Argentina; Temuco, Chile; and Pando-Barros Blancos, Uruguay) in 2010-2011. Three blood pressure (BP) measurements were obtained by trained observers using a standard mercury sphygmomanometer. Hypertension was defined as a mean systolic BP ≥140mm Hg and/or diastolic BP ≥90mm Hg and/or use of antihypertensive medications.

RESULTS

An estimated 42.5% of the study population (46.6% of men and 38.7% of women) had hypertension and an estimated 32.5% (36.0% of men and 29.4% of women) had prehypertension. Approximately 63.0% of adults with hypertension (52.5% of men and 74.3% of women) were aware of their disease condition, 48.7% (36.1% of men and 62.1% of women) were taking prescribed medications to lower their BP, and only 21.1% of all hypertensive patients (13.8% of men and 28.9% of women) and 43.3% of treated hypertensive patients (38.1% of men and 46.5% of women) achieved BP control.

CONCLUSIONS

This study indicates that the prevalence of hypertension is high while awareness, treatment, and control are low in the general population in the Southern Cone of Latin America. These data call for bold actions at regional and national levels to implement effective, practical, and sustainable intervention programs aimed to improve hypertension prevention, detection, and control.

Prevalence, Distributions and Determinants of Obesity and Central Obesity in the Southern Cone of America

BACKGROUND

Obesity is a major determinant of cardiovascular disease in South America. However, population-based data are limited.

METHODS

A total of 7,524 women and men, aged 35 to 74 years old, were randomly selected from 4 cities in the Southern Cone of Latin America between February 2010 and December 2011. Obesity clinical measurements and cardiovascular risk factors were measured using standard methodology.

RESULTS

The prevalence of obesity and central obesity were 35.7% and 52.9%, respectively. The prevalence of obesity and central obesity were higher in women, and even higher in women with lower education compared with women with higher education. In men and women obesity was associated with a higher prevalence of diabetes, odds ratio (OR) 2.38 (95% Confidence Interval [CI]: 1.86 to 3.05) and 3.01 (95%CI 2.42 to 3.74) respectively, hypertension (OR 2.79 (95%CI 2.32 to 3.36) and 2.40 (95%CI 2.05 to 2.80) respectively, dyslipidemia (OR 1.83 (95%CI 1.50 to 2.24) and 1.69 (95%CI 1.45 to 1.98), respectively, low physical activity (OR 1.38(95%CI 1.14 to 1.68) and 1.38 (95%CI 1.18 to 1.62) respectively and a lower prevalence of smoking (OR, 0.65 (95%CI 0.53 to 0.80) and 0.58(95%CI 0.48 to 0.70) respectively.

CONCLUSIONS

Obesity and central obesity are highly prevalent in the general population in the Southern Cone of Latin America and are strongly associated with cardiovascular risk factor prevalence. These data suggest that efforts toward prevention, treatment, and control of obesity should be a public health priority in the Southern Cone of Latin America.

Avaliação histopatológica de órgãos reprodutivos e bexiga de fêmeas suínas descartadas

Em um sistema intensivo de produção de suínos, as falhas reprodutivas são uma das principais razões de descarte de matrizes e queda nos índices produtivos. A infecção urinária (cistite) e as endometrites são consideradas importantes causas de descarte em fêmeas suínas, por terem consequências reprodutivas relevantes e elevarem a taxa de reposição do plantel. O presente estudo teve o objetivo de avaliar o aparelho reprodutivo e a bexiga de fêmeas suínas de descarte normal de granjas, bem como investigar a existência de relação entre as patologias encontradas. Foram examinadas 79 matrizes suínas oriundas de 20 rebanhos localizados no Estado de Santa Catarina. De cada fêmea foram coletados os ovários, fragmentos de útero e bexiga. Dentre as fêmeas avaliadas, 32 (40,5%) tinham diferentes graduações de cistite, 24 (30,4%) tinham algum tipo de inflamação uterina, e 9 (11,4%) estavam em anestro, com ovários inativos. Contudo, não foi observada dependência significativa entre cistite e endometrite nas amostras analisadas.

Long-acting beta-agonists and their association with inhaled corticosteroids in COPD

Inhaled bronchodilators, including beta(2)-agonists and antimuscaric receptor antagonists, are the mainstay of pharmacotherapy in chronic obstructive pulmonary disease (COPD). The short-acting beta(2)-agonists, including salbutamol, and fenoterol, have a rapid onset of action, a bronchodilating effect for 3-6 h and are used on demand. The long-acting beta(2)-agonists (LABAs), including salmeterol and formoterol, have 12-hour duration of action and are used with a twice-daily dosing regimen for long-term COPD treatment. Unlike salmeterol, formoterol has a rapid onset of action. Pharmacological characteristics required by novel inhaled LABAs include 24 h bronchodilator effect in vivo which would make them suitable for once daily administration (ultra-LABA), high potency and selectivity for beta(2)-adrenoceptors, rapid onset of action, low oral bioavailability (< 5%) after inhalation, and high systemic clearance. Indacaterol, which has been approved for long-term treatment of COPD in Europe and in the USA, has a 24-h duration of action and a once-daily dosing regimen. Newer ultra-LABAs, including olodaterol, vilanterol, milveterol, carmoterol, and abediterol, are in development. Combination with ICS (fluticasone/salmeterol, budesonide/formoterol, beclomethasone/formoterol) appears to provide an additional benefit over the monocomponent therapy, although the extent of this benefit is variable and often not clinically significant in all the endpoints assessed. In patients with COPD, treatment with ICS is associated with increased risk of pneumonia which should be carefully considered when assessing the risk/benefit ratio of ICS/LABA combinations. Subphenotyping of patients with COPD (e.g., frequent exacerbations, sputum eosinophilia, mixed asthma/COPD phenotype) might help identify those patients who are most likely to benefit from addition of ICS to bronchodilating treatment. Ultra-LABA/ long-acting muscarinic receptor antagonist (LAMA) combination treatment is under development and is likely to become a standard pharmacological strategy for COPD. Dual-pharmacology inhaled muscarinic antagonist-beta(2) agonist (MABA) molecules provide a new approach to the treatment of COPD.

Disseminação do vírus da doença de Aujeszky, envolvendo o comércio de reprodutores suínos de reposição

Relata-se a disseminação da infeção pelo vírus da doença de Aujeszky (VDA) a partir da comercialização de reprodutores suínos oriundos de duas granjas de reprodutores suídeos certificada (GRSC) que tiveram surto da DA. Após a confirmação do diagnóstico de DA, os suínos comercializados 37 a 45 dias anteriores aos surtos foram recolhidos, submetidos ao exame sorológico para o VDA e enviados ao abate. Nos rebanhos-destino foram realizados exames sorológicos para o VDA 17 a 37 dias após o recolhimento, naqueles que estavam lojados nas baias vizinhas àquelas onde haviam sido alojados os suínos comprados; seis meses mais tarde, foi realizada outra sorologia por amostragem dos reprodutores. No total, 52 rebanhos compraram suínos das duas granjas, e, destes, 37 (69,8%) receberam, pelo menos, um animal com sorologia positiva para o VDA. Somente sete (18,9%) deles apresentaram sorologia positiva para o VDA, e em 30 (81,1%), não houve indícios de disseminação da infecção. A contaminação pelo VDA de granjas GRSC representa enorme potencial para a disseminação da infecção, por meio do comércio de suínos de reposição. A rastreabilidade dos animais comercializados em um período anterior ao diagnóstico, com imediata remoção dos lotes de suínos dos rebanhos-destino, evitou a disseminação da infecção.

Tumor necrosis factor-alpha antagonism improves endothelial dysfunction in patients with Crohn's disease

This study assessed the presence of endothelial dysfunction in patients with inflammatory bowel diseases (IBDs) and evaluated the possible role of tumor necrosis factor (TNF)-alpha in the pathophysiology of this abnormality. Similar elevations in circulating markers of inflammation (C-reactive protein and interleukin-6) were observed in Crohn's disease and ulcerative colitis compared to controls. Endothelium-dependent vasodilation to acetylcholine was impaired in Crohn's disease, but not in ulcerative colitis. Endothelium-independent vasodilation to sodium nitroprusside, by contrast, was not different among the three groups. The TNF-alpha neutralizing antibody, infliximab, enhanced the responsiveness to acetylcholine, but not to nitroprusside, in Crohn's disease, without modifying vascular responses to both drugs in ulcerative colitis. In conclusion, despite comparable degrees of systemic inflammation in the two IBDs, endothelial dysfunction is a selective feature of Crohn's disease and is beneficially affected by intravascular TNF-alpha neutralization. These findings underscore the role of selective cytokine targeting in improving endothelial function in patients with Crohn's disease.

Regulation of Ca2+-sensitive adenylyl cyclase in gonadotropin-releasing hormone neurons

In immortalized GnRH neurons, cAMP production is elevated by increased extracellular Ca2+ and the Ca2+ channel agonist, BK-8644, and is diminished by low extracellular Ca2+ and treatment with nifedipine, consistent with the expression of adenylyl cyclase type I (AC I). Potassium-induced depolarization of GT1-7 neurons causes a dose-dependent monotonic increase in [Ca2+]i and elicits a bell-shaped cAMP response. The inhibitory phase of the cAMP response is prevented by pertussis toxin (PTX), consistent with the activation of G(i)-related proteins during depolarization. Agonist activation of the endogenous GnRH receptor in GT1-7 neurons also elicits a bell-shaped change in cAMP production. The inhibitory action of high GnRH concentrations is prevented by PTX, indicating coupling of the GnRH receptors to G(i)-related proteins. The stimulation of cAMP production by activation of endogenous LH receptors is enhanced by low (nanomolar) concentrations of GnRH but is abolished by micromolar concentrations of GnRH, again in a PTX-sensitive manner. These findings indicate that GnRH neuronal cAMP production is maintained by Ca2+ entry through voltage-sensitive calcium channels, leading to activation of Ca2+-stimulated AC I. Furthermore, the Ca2+ influx-dependent activation of AC I acts in conjunction with AC-regulatory G proteins to determine basal and agonist-stimulated levels of cAMP production.

Estudo da transmissão horizontal de Mycobacterium avium-intracellulare em suínos

O trabalho teve como objetivo estudar a transmissão horizontal de Mycobacterium avium-intracellulare (MAI) entre suínos. Doze suínos com 35 a 42 dias de idade, divididos em três grupos de quatro e alojados em salas independentes, foram inoculados por via oral com as cepas VPS1, SC1 e ATCC-13950 de Mycobacterium avium-intracellulare. A seguir, quatro suínos não inoculados foram colocados em cada grupo e mantidos na mesma baia até o abate aos 150 dias da idade. Outro grupo de quatro suínos não inoculados foi utilizado como controle. Pelo exame de fezes verificou-se que houve excreção ativa de MAI entre 14 e 42 dias pós-inoculação. A transmissão da infecção foi avaliada pelo teste de tuberculina aos 140 dias de idade e pelos exames de patologia macro e microscópica e de isolamento do MAI de órgãos. Os quatro suínos em contato com aqueles inoculados com a cepa SC1 foram contaminados, enquanto que com a cepa VPS1 apenas um e com a ATCC-13950 somente dois. Concluiu-se que houve transmissão de MAI entre os suínos mantidos na mesma baia, com as três cepas utilizadas, mas foi mais evidente com a cepa SC1, indicando que o suíno pode ser importante fonte de infecção na disseminação da doença.

Local Regulation of Gonadotroph Function by Pituitary Gonadotropin-Releasing Hormone

Cultured rat pituitary cells and immortalized pituitary gonadotrophs (alphaT3-1 cells) express specific messenger RNA transcripts for GnRH and exhibit positive immunostaining for the GnRH peptide. Each cell type released GnRH during both static culture and perifusion, albeit in lesser amounts than cultured hypothalamic cells and GT1-7 neurons. In perifused pituitary cells, exposure to a GnRH agonist stimulated the release of GnRH as well as LH. In contrast, treatment with a GnRH receptor antagonist or with GnRH antiserum decreased basal LH release. In pituitary cell cultures, a small proportion of gonadotrophs exhibited high amplitude and low frequency baseline Ca2+ oscillations in the absence of GnRH stimulation. Such spontaneous oscillations were comparable to those induced by picomolar concentrations of GnRH and could be abolished by treatment with a GnRH antagonist. These in vitro findings indicate that locally produced GnRH causes low level activation of pituitary GnRH receptors, induces spontaneous intracellular Ca2+ oscillations, and contributes to basal LH secretion in cultured pituitary cells. In vivo, such autocrine or paracrine actions of pituitary-derived GnRH could provide a mechanism for the maintenance of optimal responsiveness of the gonadotrophs to pulses of GnRH arising in the hypothalamus. The presence and actions of GnRH in the anterior pituitary gland, the major site of expression of GnRH receptors, suggest that local regulatory effects of the neuropeptide could supplement the primary hypothalamic mechanism for the control of episodic gonadotropin secretion.

Identification of two novel Mycobacterium avium allelic variants in pig and human isolates from Brazil by PCR-restriction enzyme analysis

Mycobacterium avium complex (MAC) is composed of environmental mycobacteria found widely in soil, water, and aerosols that can cause disease in animals and humans, especially disseminated infections in AIDS patients. MAC consists of two closely related species, M. avium and M. intracellulare, and may also include other, less-defined groups. The precise differentiation of MAC species is a fundamental step in epidemiological studies and for the evaluation of possible reservoirs for MAC infection in humans and animals. In this study, which included 111 pig and 26 clinical MAC isolates, two novel allelic M. avium PCR-restriction enzyme analysis (PRA) variants were identified, differing from the M. avium PRA prototype in the HaeIII digestion pattern. Mutations in HaeIII sites were confirmed by DNA sequencing. Identification of these isolates as M. avium was confirmed by PCR with DT1-DT6 and IS1245 primers, nucleic acid hybridization with the AccuProbe system, 16S ribosomal DNA sequencing, and biochemical tests. The characterization of M. avium PRA variants can be useful in the elucidation of factors involved in mycobacterial virulence and routes of infection and also has diagnostic significance, since they can be misidentified as M. simiae II and M. kansasii I if the PRA method is used in the clinical laboratory for identification of mycobacteria.

No cardiovascular effects of single-dose pseudoephedrine in patients with essential hypertension treated with beta-blockers

OBJECTIVE

The use of the decongestant pseudoephedrine has been cautioned in patients with arterial hypertension, due to the possible rise in blood pressure induced by the sympathostimulatory properties of the drug. This effect could be enhanced in hypertensives treated with beta-blockers, in whom the vasoconstrictor effect of alpha-adrenergic stimulation is unbalanced. The purpose of this study was to investigate the cardiovascular response to pseudoephedrine in hypertensive patients treated with different types of beta-blockers.

METHODS

We recruited 29 (18 males) mild-to-moderate essential hypertensive patients [mean age 49(2) years] in a randomized, placebo-controlled, crossover trial. All participants received either placebo, or a nonselective (propranolol 160 mg once daily) or a selective (atenolol 100 mg once daily) beta-blocker for 1 week. At the end of each period, all patients received a single oral dose of pseudoephedrine (60 mg) and their blood pressure and heart rate were monitored at repeated intervals for 2 h.

RESULTS

After 1 week of propranolol or atenolol, patients had significantly lower systolic blood pressure and heart rate than after placebo, whereas diastolic blood pressure was not significantly modified. The acute administration of pseudoephedrine did not change systolic and diastolic blood pressure and heart rate from baseline at the end of any of the treatment periods.

CONCLUSIONS

A standard oral dose of pseudoephedrine does not significantly affect blood pressure values in hypertensive patients treated with beta-blockers, and therefore may be safely used in this subset of patients.

Autocrine regulation of gonadotropin-releasing hormone secretion in cultured hypothalamic neurons

Episodic hormone secretion is a characteristic feature of the hypothalamo-pituitary-gonadal system, in which the profile of gonadotropin release from pituitary gonadotrophs reflects the pulsatile secretory activity of GnRH-producing neurons in the hypothalamus. Pulsatile release of GnRH is also evident in vitro during perifusion of immortalized GnRH neurons (GT1-7 cells) and cultured fetal hypothalamic cells, which continue to produce bioactive GnRH for up to 2 months. Such cultures, as well as hypothalamic tissue from adult rats, express GnRH receptors as evidenced by the presence of high-affinity GnRH binding sites and GnRH receptor transcripts. Furthermore, individual GnRH neurons coexpress GnRH and GnRH receptors as revealed by double immunostaining of hypothalamic cultures. In static cultures of hypothalamic neurons and GT1-7 cells, treatment with the GnRH receptor antagonist, [D-pGlu1, D-Phe2, D-Trp(3,6)]GnRH caused a prominent increase in GnRH release. In perifused hypothalamic cells and GT1-7 cells, treatment with the GnRH receptor agonist, des-Gly10-[D-Ala6]GnRH N-ethylamide, reduced the frequency and increased the amplitude of pulsatile GnRH release, as previously observed in GT1-7 cells. In contrast, exposure to the GnRH antagonist analogs abolished pulsatile secretion and caused a sustained and progressive increase in GnRH release. These findings have demonstrated that GnRH receptors are expressed in hypothalamic GnRH neurons, and that receptor activation is required for pulsatile GnRH release in vitro. The effects of GnRH agonist and antagonist analogs on neuropeptide release are consistent with the operation of an ultrashort-loop autocrine feedback mechanism that exerts both positive and negative actions that are necessary for the integrated control of GnRH secretion from the hypothalamus.

Mediation of cyclic AMP signaling by the first intracellular loop of the gonadotropin-releasing hormone receptor

The gonadotropin-releasing hormone (GnRH) receptor, which is a unique G protein-coupled receptor without a C-terminal cytoplasmic domain, activates both inositol phosphate (InsP) and cAMP signaling responses. The function of the highly basic first intracellular (1i) loop of the GnRH receptor in signal transduction was evaluated by mutating selected residues located in its N and C termini. Replacements of Leu58, Lys59, Gln61, and Lys62 at the N terminus, and Leu73, Ser74, and Leu80 at the C terminus, caused no change in binding affinity. The agonist-induced InsP and cAMP responses of the Q61E and K59Q,K62Q receptors were also unaffected, but the L58A receptor showed a normal InsP response and an 80% decrease in cAMP production. At the C terminus, the InsP response of the L73R receptor was normal, but cAMP production was reduced by 80%. The EC50 for GnRH-induced InsP responses of the S74E and L80A receptors was increased by about one order of magnitude, and the cAMP responses were essentially abolished. These findings indicate that cAMP signaling from the GnRH receptor is dependent on specific residues in the 1i loop that are not essential for activation of the phosphoinositide signaling pathway.

Muscarinic regulation of intracellular signaling and neurosecretion in gonadotropin-releasing hormone neurons

Agonist activation of cholinergic receptors expressed in perifused hypothalamic and immortalized GnRH-producing (GT1-7) cells induced prominent peaks in GnRH release, each followed by a rapid decrease, a transient plateau, and a decline to below basal levels. The complex profile of GnRH release suggested that acetylcholine (ACh) acts through different cholinergic receptor subtypes to exert stimulatory and inhibitory effects on GnRH release. Whereas activation of nicotinic receptors caused a transient increase in GnRH release, activation of muscarinic receptors inhibited basal GnRH release. Nanomolar concentrations of ACh caused dose-dependent inhibition of cAMP production that was prevented by pertussis toxin (PTX), consistent with the activation of a plasma-membrane Gi protein. Micromolar concentrations of ACh also caused an increase in phosphoinositide hydrolysis that was inhibited by the M1 receptor antagonist, pirenzepine. In ACh-treated cells, immunoblot analysis revealed that membrane-associated G(alpha q/11) immunoreactivity was decreased after 5 min but was restored at later times. In contrast, immunoreactive G(alpha i3) was decreased for up to 120 min after ACh treatment. The agonist-induced changes in G protein alpha-subunits liberated during activation of muscarinic receptors were correlated with regulation of their respective transduction pathways. These results indicate that ACh modulates GnRH release from hypothalamic neurons through both M1 and M2 muscarinic receptors. These receptor subtypes are coupled to Gq and Gi proteins that respectively influence the activities of PLC and adenylyl cyclase/ion channels, with consequent effects on neurosecretion.

Histochemical and lectinhistochemical studies on nasal mucosa of pigs with or without respiratory diseases

Histochemical and lectinhistochemical examinations were carried out on nasal mucosa of pigs with or without respiratory diseases. As the results, both acid and neutral mucins coexisted in nasal mucosa of normal pigs while acid sialomucins were mainly observed in nasal mucosa of pigs infected with Bordetella bronchiseptica and/or Pasteurella multocida. Lectinhistochemistry revealed that the nasal epithelial cells of normal pigs were rich in N-acetylgalactosamine, fucose and N-acetyl-glucosamine residues which showed a tendency to disappear in porcine cytomegalovirus infection and to increase in atrophic rhinitis, respectively.

Extracellular sodium removal increases release of neuropeptide Y-like immunoreactivity from rat brain hypothalamic synaptosomes: involvement of intracellular acidification

Rat hypothalamic synaptosomes were exposed via superfusion to various stimuli and the release of neuropeptide Y-like immunoreactivity (NPY-LI) was measured by means of radioimmunoassay procedures. High KCl (15-50 mM) concentration dependently evoked NPY-LI release; the evoked overflow reached a plateau at 30 mM KCl and was abolished in the absence of Ca2+ ions. Furthermore, a remarkable NPY-LI overflow was obtained when extracellular Na+ ions were removed. Low external Na(+)-evoked NPY-LI release was independent of the presence of Ca2+ ions from the superfusion medium. It is well known that the reduction of external Na+ ions activates the release of several neurotransmitters through an inversion of the uptake-carrier working direction; but such mechanisms, involving Na(+)-dependent uptake, have never been described for neuropeptides. The alteration of the extracellular Na+ concentration is able to modify the concentration of the intracellular Ca2+ and H+ ions. In fact, the concentrations of these two ions are regulated through Na(+)-dependent exchange mechanisms across the membrane. Amiloride, blocking the Na+/H+ exchanger, was able to maintain low Na(+)-evoked NPY-LI release, underlying that the blockade of the exchanger preserves the H+ accumulation induced by the reduction of the external Na+ ions. NPY-LI release could also be stimulated by nigericine, a proton ionophore, showing that the intracellular acidification is responsible for NPY-LI release. Intracellular acidification may stimulate Ca2+ ion release from intracellular stores, as has been shown by other workers. Large dense-core vesicles containing the peptide appear to be more sensitive to local intracellular Ca2+ release compared with extracellular Ca2+ ion entry through voltage-dependent channels.

Platelet alpha 2-adrenergic receptors in hypercholesterolemia: relationship between binding studies and epinephrine-induced platelet aggregation

BACKGROUND

Platelets isolated from patients with hypercholesterolemia are more sensitive in vitro to various aggregating agents, including epinephrine, than those isolated from normocholesterolemic subjects. Increased platelet reactivity is one mechanism that may explain the enhanced risk of thromboembolism in hypercholesterolemia. This study assessed whether platelet hyperreactivity to epinephrine in hypercholesterolemia is associated with higher alpha 2-adrenergic receptor density or affinity for epinephrine.

METHODS

Platelet aggregation and binding studies, with use of [3H]yohimbine as ligand, were performed on platelets isolated from 30 patients with type IIa hypercholesterolemia and 23 control subjects.

RESULTS

Platelet aggregation in response to epinephrine was significantly higher in patients with hypercholesterolemia than in control subjects. A statistically significantly higher alpha 2-adrenergic receptor density was observed in a subgroup of 13 patients with hypercholesterolemia than in 13 sex- and age-matched control subjects (280 +/- 61 and 230 +/- 49 fmol/mg protein respectively; p < 0.03), but no difference was observed in receptor affinity for the ligand. In these subgroups plasma total and levels of low-density lipoprotein (LDL) cholesterol were inversely correlated with platelet aggregation but directly correlated with platelet receptor density.

CONCLUSION

Platelet alpha 2-adrenergic receptor density is increased in hypercholesterolemia and directly correlates with plasma total and levels of LDL cholesterol, providing at least a partial explanation for the enhanced platelet response to epinephrine that is observed in hypercholesterolemia.

Activation of LH receptors expressed in GnRH neurons stimulates cyclic AMP production and inhibits pulsatile neuropeptide release

The GT1-7 cell line of immortalized GnRH neurons has been shown to express receptors for GnRH, LH, and prolactin, as well as a variety of other hormones and transmitters. Treatment of GT1-7 cells with hCG caused a dose-dependent increase in cAMP production, with a rapid increase during the first 15 min and a subsequent decrease that was prevented by pre-treatment with pertussis toxin. Furthermore, the stimulatory effect of cholera toxin on cAMP production was inhibited by hCG in a dose-dependent manner. These data indicate that the LH receptors expressed in GT1-7 cells are coupled to adenylyl cyclase both stimulatory (Gs) and inhibitory (Gi) proteins. In perifused cell cultures, treatment with forskolin and 8-bromo cAMP increased the amplitude of spontaneous GnRH release. However, treatment with nanomolar concentrations of hCG abolished pulsatile GnRH release from both GT1-7 cells and rat hypothalamic cells. The similarity of hCG action on pulsatile GnRH release to that of extracellular Ca2+ depletion and calcium channel antagonists, and its partial resistance to potassium-induced depolarization, suggest that it results from inhibition of plasma-membrane ion channel activity. It is probable that the inhibitory action of hCG on pulsatile GnRH release is responsible for initiation of the suppression of pituitary LH secretion during pregnancy.

Presynaptic A2-adrenoceptors and neuropeptide Y Y2 receptors inhibit [3H]noradrenaline release from rat hypothalamic synaptosomes via different mechanisms

Presynaptic receptors may reduce transmitter release with different mechanisms. Both the alpha 2-agonist, clonidine and the Y2-agonist, neuropeptide Y fragment 13-36 (NPY 13-36), induce a concentration-dependent inhibition of the 4-aminopyridine (4-AP)-evoked [3H]noradrenaline ([3H]NA) release from hypothalamic synaptosomes. Changes in alpha 2- and Y2-modulation of noradrenaline (NA) release were observed by lowering the calcium influx with the use of omega-conotoxin (omega-CgTx), a calcium-channel blocking agent. In these experimental conditions, clonidine was less active, whereas NPY 13-36 preserved its efficacy. It therefore seems possible that presynaptic alpha 2-adrenoceptors can primarily inhibit NA release by reducing calcium influx via voltage-sensitive calcium channels (VSCC), while Y2-receptors may inhibit the intracellular release process with a mechanism independent of the calcium entry.

Platelet alpha 2-adrenoceptors and diurnal changes of platelet aggregability in hypertensive patients

OBJECTIVE

To analyse whether platelets from hypertensive patients have an increased responsiveness to aggregating agents during morning hours and whether these changes might be related to concurrent changes in platelet membrane alpha 2-adrenoceptor characteristics, plasma catecholamine and cortisol levels, and blood pressure values.

DESIGN AND METHODS

Blood samples from 14 mild-to-moderate essential hypertensive males were collected in the morning (0700-0900 h) and the evening (1900-2100 h) to determine platelet aggregability responses to adrenaline and ADP, platelet alpha 2-adrenoceptor number and binding affinity to [3H]-yohimbine, plasma catecholamines and cortisol. During the same day patients underwent 24-h ambulatory blood pressure monitoring.

RESULTS

The lowest concentration of adrenaline required to induce biphasic aggregation was significantly lower in the morning than in the evening, indicating an increased morning platelet aggregability to adrenaline; the minimum ADP concentration inducing aggregation was similar in morning and evening samples. There were no significant differences between morning and evening samples in platelet alpha 2-adrenoceptor number and binding affinity. Plasma adrenaline, noradrenaline and cortisol levels were higher in the morning than in the evening, but no correlation was observed between hormonal changes and the morning increase in platelet sensitivity to adrenaline. Ambulatory blood pressure recording showed abrupt morning elevations in systolic and diastolic blood pressures over sleeping values. However, morning blood pressure readings were not significantly different from those recorded during the rest of the day and in the evening. The morning rise in mean arterial pressure displayed a significant inverse correlation with the increased platelet sensitivity to adrenaline that was observed during the same hours.

CONCLUSIONS

The results indicate that the increased morning responsiveness to adrenaline that was observed in platelets obtained from hypertensive patients does not appear to be mediated by changes in the characteristics of platelet membrane alpha 2-adrenoceptors, but morning blood pressure elevations might play some role in inducing this platelet hyper-reactivity.

Effects of benazepril on stress testing blood pressure in essential hypertension

The effects of different doses of the angiotensin-converting enzyme inhibitor benazepril on cardiovascular response to a set of standardized laboratory tasks were analyzed. Eighteen patients (15 men and 3 women) with mild-to-moderate essential hypertension were randomly allocated to receive 10 or 20 mg of benazepril, or placebo, each administered once daily for 2 weeks, according to a double-blind, 3-period design. At the end of each treatment period, patients were examined at resting baseline and while performing mental arithmetic, handgrip and cycle ergometry tests. In comparison with placebo, the average reductions in resting systolic blood pressure (BP) were 8.7 mm Hg (95% confidence intervals [CI] -15.2 to -2.1) with 10 mg of benazepril, and 7.8 mm Hg (95% CI -14.4 to -1.3) with 20 mg; the corresponding reductions in resting diastolic BP were 5.1 mm Hg (95% CI -8.7 to -1.4) and 6.8 mm Hg (95% CI -10.4 to -3.1) (all p < 0.05). During mental arithmetic, the reductions in systolic BP were 10.4 mm Hg (95% CI -17.4 to -3.4) with 10 mg of benazepril, and 13.8 mm Hg (95% CI -20.8 to -6.8) with 20 mg; diastolic BP was reduced by 4.5 mm Hg (95% CI -8.5 to -0.5) and 8.3 mm Hg (95% CI -13.2 to -4.3), respectively (all p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Region-specific inhibition of potassium-evoked [3H]noradrenaline release from rat brain synaptosomes by neuropeptide Y-(13-36). Involvement of NPY receptors of the Y2 type

The effects of the Y2 receptor agonist neuropeptide Y NPY-(13-36) on the depolarization-evoked release of [3H]noradrenaline (NA) from synaptosomal preparations of the medulla oblongata, the hypothalamus, the hippocampal formation and the parieto-occipital cortex of the male rat were studied. NPY-(13-36) (0.1-100 nM) caused a concentration-related inhibition of the depolarization-induced release of [3H]NA in all areas studied, except the parieto-occipital cortex. The results indicate that NPY Y2 receptors are present on NA terminals in all areas studied, except the parieto-occipital cortex and inhibit depolarization-evoked [3H]NA release.

Isolation and identification of chicken infectious anemia virus in Brazil

Seven chicken infectious anemia virus (CIAV) isolates were obtained from seven broiler flocks with poor performance in two states of Brazil. All isolates induced thymus atrophy, bone-marrow aplasia, and low hematocrit values when inoculated into 1-day-old susceptible chicks. The CIAV isolates were resistant to treatment with chloroform and were able to pass through 50-nm-pore-size filters. CIAV-specific antigens could be demonstrated in tissues of experimentally infected chicks using a monoclonal antibody specific for CIAV. These characteristics of the virus and the virus-induced lesions demonstrate that CIAV is present in Brazil and that the virus is associated with production problems.

A discrepancy between platelet alpha 2-receptor density and functional circulatory changes in hypertensives

To investigate whether differences exist in peripheral alpha 2-adrenoceptors between normotensive and hypertensive subjects, we determined platelet alpha 2-adrenoceptor density in 10 (7 males) untreated essential hypertensives (mean age of 51.1 years, range of 44-59 years) and in 10 age- and sex-matched normotensive controls. Moreover, in hypertensive patients, we examined the relationship between receptor density and cardiovascular reactivity to mental arithmetic, static handgrip, and bicycle exercise, to verify the hypothesis that alpha 2-adrenoceptors might play a role in modulation of hemodynamic response to sympathetic stimuli. alpha 2-Adrenoceptor density, as calculated by binding of [3H]yohimbine to platelets, was significantly higher in essential hypertensives (314.8 +/- 38.7 fmol/mg) than in normotensive subjects (213.6 +/- 34.7 fmol/mg) (p less than 0.05), whereas receptor affinity was similar in both groups (4.0 +/- 0.5 nM hypertensives, 4.3 +/- 0.5 nM normotensives; p greater than 0.05). Mental arithmetic increased mean arterial pressure (MAP) by 21.5% from basal values and heart rate (HR) by 13.2%. During isometric exercise, MAP increased by 38.1% and HR by 24.7%, while during bicycle ergometry, mean increases in MAP and HR from baseline were of 27.2 and 54.3%, respectively. No correlation was found between platelet alpha 2-adrenoceptor density and percent changes in MAP induced by all tests, or between adrenoceptors and absolute basal and peak MAP values. Our findings suggest that in hypertensive patients, peripheral alpha 2-adrenoceptors are increased with respect to matched normotensives, but these receptors seem not to be involved in the modulation of cardiovascular adaptation to enhanced sympathetic activity.

Heart rate variability and ventricular ectopic activity in hypertensive patients

In order to investigate whether the severity of ventricular ectopic beats in hypertensive patients is influenced by the autonomic drive to the heart, we evaluated the relationship between the degree of dysrhythmias and 24-h spontaneous heart rate variability, an index of sympatho-vagal balance at cardiac level. Ambulatory 24-h ECG monitoring was used to examine 42 untreated essential hypertensives, previously scored for the presence and the extent of hypertensive target organ damage. No significant difference was found in the prevalence of complex ventricular ectopic beats in patients with a heart rate variability that was lower and higher than the arbitrary cut off points selected to divide subjects into groups. Neither heart rate variability nor the degree of arrhythmias was correlated with blood pressure levels, whereas the degree of ectopy was influenced by the presence of target organ damage and left ventricular hypertrophy (by ECG). Our results seem to exclude an association between dysrhythmias in hypertensives and autonomic outflow to the heart as detected by the analysis of heart rate variability.

Peroxidative events in stored platelet concentrates

Changes in metabolic and functional activity of platelets stored as platelet concentrates in plastic bags highly permeable to gases were investigated. The following parameters were measured daily: pH, pO2, pCO2, HCO3, glucose, lactic acid, lactic dehydrogenase, cellular ATP and platelet aggregation induced by different agents (collagen and ADP). As indexes of lipid peroxidative damage, the cellular levels of conjugated dienes, malonyldialdehyde and some antioxidant molecules such as coenzyme Q10 and vitamin E were determined. A marked increase in pO2, conjugated dienes, malonyldialdehyde, lactic acid and lactic dehydrogenase activity was observed during the preservation. Platelet ATP content was unmodified and a remarkable decrease in platelet aggregability was found. pCO2, cyclooxygenase activity, vitamin E, coenzyme Q10, bicarbonate and glucose showed a rapid fall. Our data seem to indicate a preservation of platelet metabolic activity and a correlation between increased lipid peroxidation and functional impairement.

Effects of sustained-release verapamil on 24-hour ambulatory blood pressure and on pressor response to isometric exertion in hypertensive patients

The antihypertensive effect of a drug should be present not only at rest, but also during usual daily activities and pressor stimuli. In our study, we tested the impact of a new formulation of sustained-release (SR) verapamil (240-mg tablets), given once or twice daily, on 24-h ambulatory blood pressure (BP) and on pressor response to isometric exercise (handgrip). Fourteen mildly to moderately essential hypertensive patients were included in a single-blind placebo-controlled trial. The mean titrated dose of verapamil required to normalize office BP was 430 +/- 28 mg/day. Mean 24-h waking (7 a.m.-11 p.m.) and sleeping (11 p.m.-7 a.m.) blood pressures were significantly lower after verapamil than after placebo. The absolute levels of BP achieved at peak of handgrip (30% of maximal voluntary contraction for 3 min) were significantly reduced by verapamil with respect to placebo. However, due to the lower starting values, the pressor increment to the isometric work was not significantly modified by the active treatment. In conclusion, SR verapamil seems to provide a blood pressure lowering effect during all times of the day. It attenuates the surges in BP associated with handgrip exercise.

Twenty-four-hour blood pressure monitoring after a single dose of sustained-release verapamil

The antihypertensive effect of a single dose of 240 mg sustained-release (S-R) verapamil was investigated by ambulatory blood pressure (BP) monitoring in 13 patients with mild to moderate essential hypertension. Following a 2-week washout period, 24-hour BP monitoring was carried out with a Spacelabs ICR 5300 device following random administration of a tablet of S-R verapamil or placebo; BP recording was repeated after crossover 3 to 7 days later. Average whole-day systolic and diastolic BPs were significantly lower after verapamil (130.1 +/- 2.6/87.1 +/- 1.2 mmHg) than after placebo (142.1 +/- 3.3/95.8 +/- 2.1 mmHg) (p less than 0.01). Mean waking BP was 146.4 +/- 3.6/99.1 +/- 2.2 mmHg after placebo and 135.2 +/- 3.3/90.5 +/- 1.7 mmHg after verapamil (p less than 0.01); during sleeping hours BP was 133.8 +/- 3.1/88.7 +/- 2.6 mmHg following placebo and 122.2 +/- 2.3/80.9 +/- 1.8 mmHg following verapamil (p less than 0.01). Blood pressure profile was significantly reduced by verapamil up to 20 hours after tablet administration, while from 21 to 24 hours after drug intake BP values were similar to placebo. Response to verapamil was not correlated to the pretreatment BP values and to the patient's age. In summary, this study suggests that acute administration of 240 mg S-R verapamil in hypertensive patients produces a BP reduction during 24-hour, daytime, and nighttime periods. The hypotensive efficacy is preserved for many hours after tablet intake and seems to be due to individual variation in cardiovascular reactivity to the drug.

Casual versus 24-hour ambulatory blood pressure recording in the evaluation of chronic administration of sustained-release verapamil

Although ambulatory blood pressure monitoring has been used widely for the evaluation of antihypertensive treatment, little information is available regarding the comparison between this method and casual BP measurement during drug trials. In our study, we tested the efficacy of a new formulation of verapamil, 240 mg sustained-release tablets, and compared the degree of BP reduction as detected by casual (standard mercury manometer) and by 24-hour ambulatory recording (Spacelab ICR 5300). A statistically significant fall in casual BP was observed after verapamil with respect to placebo. Moreover, 24-hour, waking and sleeping ambulatory BPs were significantly reduced by verapamil. The mean BP reduction was similar for office (20.1/16.1 +/- 4.3/3.1 mmHg) and for day-time ambulatory monitoring (13.4/10.7 +/- 4.2/1.9 1.9 mmHg), but no correlation was found between BP fall recorded by the two techniques for individual subjects. This study suggests that sustained-release verapamil is an effective antihypertensive drug. Individual mean BP reduction outside the clinic may not be predicted from office readings and therefore ambulatory BP recording seems to provide a better basis for testing the efficacy of drugs.

Effect of sustained-release verapamil therapy on the blood pressure at rest and on the pressor response to isometric exertion in hypertensive patients

The effect of a new formulation of verapamil sustained release (SR) 240 mg tablets on resting blood pressure (BP) and on the pressor response to isometric exertion have been examined in a single-blind, placebo-controlled, cross-over study in 12 hypertensive patients (mean age 45 years). SR verapamil and placebo were administered every 12 h for 6 consecutive weeks. At the end of each period of treatment BP and heart rate (HR) were measured at rest and during isometric exercise, performed as a handgrip (HG) test for 3 min at 30% of the maximum voluntary contraction. There was a significant reduction in resting systolic and diastolic BP, with no change in HR. BP and HR at peak exercise were lower after verapamil than after placebo, but the maximal absolute increase did not change during verapamil therapy. The results are compatible with a role of SR verapamil b.d. in reducing resting BP in hypertension, and in lowering very high pressure at the peak of a HG test, without modifying the physiological reactivity of cardiovascular system.

Biochemistry of packed red blood cell concentrates stored in PAGGS-sorbitol solution for 42 days

We investigated metabolic, blood gas and acid-base balance modifications of erythrocyte concentrates resuspended in PAGGS-sorbitol solution during 6 weeks of storage. Glucose utilization was impaired during the last 2 weeks, while the intraerythrocytic ATP level decreased only 50% from the 1st to the 6th week. The K+ and Hb concentration in the medium showed a progressive increase which was more pronounced during the last 2 weeks. The decrease in pH progressed to reach 6.27 at the 6th week of storage. Intraerythrocytic 2,3-DPG dropped rapidly in the course of the 1st week and the percentage of oxyhemoglobin showed a remarkable increase after the 1st week (90%). Our data suggest that erythrocyte concentrates in PAGGS-sorbitol should be transfused, for optimal efficacy, within 4 weeks.