Search

Microplastic pollution and associated chemical contaminants is a topic of growing interest. In recent years, the number of publications reporting the presence of microplastics (MPs) in marine organisms has increased exponentially. However, there is a gap in knowledge about the trophic transfer of contaminants from microplastics to animal tissues, as well as possible health effects. In this study we analyzed the trophic transfer and biomagnification of three chemical pollutants present in microplastics: dichlorodiphenyldichloroethylene (DDE-p,p'), benzophenone 3 (BP-3) and chlorpyrifos (CPS). The reference values used were concentrations found in environmental microplastics in the Canary Islands (minimum and maximum). European seabass (Dicentrarchus labrax) were fed for 60 days with 5 different treatments: A) feed; B) feed with chemical pollutants at maximum concentration; C) feed + 10 % virgin MPs; D) feed + 10 % MPs with chemical pollutants at minimum concentration; E) feed + 10 % MPs with chemical pollutants at maximum concentration. We detected trophic transfer of DDE-p,p', CPS and BP-3 from the feed (treatment B) to the muscle and liver of fish. In the case of DDE-p,p', transfer to liver and muscle was also observed in the treatments consisting of feed plus plastics with different levels of contamination (C, D and E). No effect of the experimental treatments on fish condition indices was observed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Marine microplastic pollution is one of the biggest environmental problems we face. The growth of plastic production has not ceased since the 1950s and it is currently estimated that 368 tons of plastic were produced in 2019 (PlascticsEurope, 2020). Geyer et al. (2017) estimate that 79% of the plastic produced in the world still remains in the environment; this plastic due to the effect of degradation and subsequent fragmentation, is present in the form of microplastics in all oceans and, due to its small size can be ingested by fish and filter-feeding organisms. In addition, microplastics have additives and chemical contaminants associated with them, and the potential effect of microplastic ingestion on marine organisms, and through them, the potential risk to humans, is unknown. In the present study, European seabass (Dicentrarchus labrax) were fed for 60 days with three treatments: Control (feed), MP (feed with 10% virgin microplastics) and EMP (feed with 10% environmental microplastics), being the first study to evaluate long-term accumulation of contaminants due to ingestion of environmental microplastics (EMP) in fish. Both plastic additives such as PBDEs, and chemical contaminants adsorbed from the environment such as PCBs and DDE, were analyzed in the EMP, feed and liver. The concentration of microplastics in the feed was calculated based on the MPs/zooplankton wet weight (WW) ratio of 0.1 found in an area of maximum accumulation in the Canary Islands. Therefore, it is an experiment that simulates real conditions, but in the worst-case scenario, using both, concentrations based on data obtained in oceanographic campaigns and microplastics collected from the environment. Our results show that in this scenario, additives and chemical contaminants adsorbed on EMPs bioaccumulate in fish liver due to long-term ingestion of microplastics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Plastic pollution has become a global problem for marine ecosystems. Microplastics (MPs) are consumed by several marine organisms, including benthic and pelagic fish species that confuse them with food sources, thus contributing to bioaccumulation along the food chain. In addition to structural intestinal damage, ingestion of MPs represents a pathway for fish exposure to potentially hazardous chemicals, too. Most of them are endocrine disrupters, genotoxic or induce immune depression in fish. Accordingly, we assessed the combined toxicological effects of microplastics (MPs) and adsorbed pollutants by adding them to marine fish diet. European sea bass (Dicentrarchus labrax) juveniles were fed for 60 days with feeds containing polypropylene MPs, either virgin or contaminated with chemical pollutants (a blend of dichlorodiphenyldichloroethylene, chlorpyrifos, and benzophenone-3). The data demonstrated a synergic action of MPs and chemical pollutants to induce an inflammatory-like response in distal intestine of sea bass as shown by the up regulation of cytokine il-6 and tnf-α expression. Morphological analysis detected the presence of a focus of lymphocytes in anterior and posterior intestinal segments of fish fed with contaminants in the diet. With regard to microbiota, significant changes in bacterial species richness, beta diversity, and composition of gut microbiota were observed as a consequence of both pollutants and polluted MPs ingestion. These perturbations in gut microbial communities, including the reduction of beneficial lactic acid bacteria and the increase in potential pathogenic microorganism (Proteobacteria and Vibrionales), were undeniable signs of intestinal dysbiosis, which in turn confirmed the signs of inflammation caused by pollutants, especially when combined with MPs. The results obtained in this study provide, therefore, new insights into the potential risks of ingesting MPs as pollutant carriers in marine fish., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background and Aims: Epidemiological studies show that obese adolescents are candidates to suffer cardiovascular pathologies in adulthood. In order to detect subfractions with a diagnostic value for future cardiovascular disorders, we analyzed the complete lipoprotein profile of severely obese adolescents., Methods and Results: Twenty-eight obese adolescents free from comorbidities were admitted into a weight reduction program. Anthropometric parameters were monitored. The circulating lipoproteins and glycemia were measured at the beginning and at the end of the study by conventional blood analysis as well as by using lipoprotein electrophoresis. Twenty-one puberty-matched normal-weight adolescents were recruited as controls. After 4 months, participants improved anthropometric parameters. Blood analysis indicated that circulating lipoproteins were in the healthy range during intervention. Nevertheless, results obtained from lipoprotein electrophoresis showed a significant increase in the large high-density lipoprotein subfraction in the obese population at the end of intervention, but significantly lower than normal-weight counterparts. In addition, intermediate- and low-density lipoprotein subfractions were in the healthy range in controls and in obese adolescents during intervention., Conclusions: Altogether, it seems that the obese adolescents with no comorbidities do not develop a clear dyslipidemia. However, low values of large high-density lipoprotein subfractions could be considered as candidate predictors to develop cardiovascular disease in the future. For this reason, diet and exercise are key tools to fight against this pathology., Registration Number for Clinical Trials: ISRCTN99414527., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2021 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

The production of erythropoietin (Epo) is modulated by renal tissue oxygen tension, which in principle depends on both arterial oxygen content (CaO2) and arterial oxygen tension (PaO2). Uncontrolled observational studies suggest that alterations in CaO2 fundamentally regulate Epo synthesis. We sought to establish whether reduced CaO2 enhances plasma Epo concentration independently of PaO 2 . In a blinded crossover study, 8 healthy young subjects were exposed to three conditions: room air (normoxia); 11% oxygen balanced in nitrogen, which lowers both CaO2 and PaO2 (hypoxia); and carbon monoxide plus normoxia, which decreases CaO2 to the same degree as hypoxia while preserving PaO2 (hypoxemia). Arterial blood samples were obtained prior to and throughout the 5 hours of exposure to each condition. In the hypoxic conditions, average CaO2 was reduced to similar levels, whereas PaO2 was only decreased with exposure to hypoxia. Plasma Epo concentration was increased in both hypoxic conditions relative to normoxia after 150 min of exposure and was augmented more than two-fold after 300 min, with no difference between hypoxic conditions. Reduced CaO2 induces similar increases in circulating Epo concentration irrespective of PaO2 manipulation, demonstrating that CaO2 is the critical variable regulating Epo production., (Copyright © 2018 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Traditionally, a major part of aquaculture technology requires fish oil (FO) and fish meal (FM) to produce the aquafeed for farmed species. FO is the main source of persistent organic pollutants (POPs) in fish feed. In recent years, the use of vegetable-origin ingredients in fish feeds has been increasingly studied as an alternative to reduce the levels of these lipophilic pollutants in farmed species. The aim of this study was to evaluate the effect of the use of dietary vegetable oils in the farming of European sea bass (Dicentrarchus labrax) on the contents in persistent - polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) - and semi persistent pollutants - polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (BDEs) - of their edible parts. A total of 60 seabass muscle pools were obtained from fish farmed employing six experimental diets, which contained different percentages of FO (6 vs. 3%) and FM (20%, 10% and 5%). We did not observe differences in the contamination level of seabass muscle in relation to the percentage of FM in their diet. However, the fish farmed using feed which had lower levels of FO (3%) showed significantly lower muscle levels of ΣPCBs and carcinogenic PAHs (Σc-PAHs), with a reduction of 25.6% and 95.11% (respectively), as compared with those fished raised with feed with higher levels of FO (6%). Also much lower levels were found in OCPs such as sum of DDTs (30.88% of reduction), sum of chlordanes (42.85% of reduction), and sum of BDEs (48.16% of reduction) in those seabass fed with a lower percentage of FO. The results of this study indicate that the use of alternative feed ingredients that allow the employment of low percentage of FO in feeds help to reduce the load of several toxic pollutants in the fillets of European seabass., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: The use of medications to treat attention deficit hyperactivity disorder (ADHD) has increased, but the prevalence of ADHD medication use across different world regions is not known. Our objective was to determine regional and national prevalences of ADHD medication use in children and adults, with a specific focus on time trends in ADHD medication prevalence., Methods: We did a retrospective, observational study using population-based databases from 13 countries and one Special Administrative Region (SAR): four in Asia and Australia, two in North America, five in northern Europe, and three in western Europe. We used a common protocol approach to define study populations and parameters similarly across countries and the SAR. Study populations consisted of all individuals aged 3 years or older between Jan 1, 2001, and Dec 31, 2015 (dependent on data availability). We estimated annual prevalence of ADHD medication use with 95% CI during the study period, by country and region and stratified by age and sex. We reported annual absolute and relative percentage changes to describe time trends., Findings: 154·5 million individuals were included in the study. ADHD medication use prevalence in 2010 (in children aged 3-18 years) varied between 0·27% and 6·69% in the countries and SAR assessed (0·95% in Asia and Australia, 4·48% in North America, 1·95% in northern Europe, and 0·70% in western Europe). The prevalence of ADHD medication use among children increased over time in all countries and regions, and the absolute increase per year ranged from 0·02% to 0·26%. Among adults aged 19 years or older, the prevalence of any ADHD medication use in 2010 varied between 0·003% and 1·48% (0·05% in Asia and Australia, 1·42% in North America, 0·47% in northern Europe, and 0·03% in western Europe). The absolute increase in ADHD medication use prevalence per year ranged from 0·0006% to 0·12%. Methylphenidate was the most commonly used ADHD medication in most countries., Interpretation: Using a common protocol and data from 13 countries and one SAR, these results show increases over time but large variations in ADHD medication use in multiple regions. The recommendations of evidence-based guidelines need to be followed consistently in clinical practice. Further research is warranted to describe the safety and effectiveness of ADHD medication in the short and long term, and to inform evidence-based guidelines, particularly in adults., Funding: None., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Severe exercise intolerance (EI), demonstrated by impaired peak oxygen consumption, intrinsically characterizes heart failure with preserved ejection fraction (HFpEF). Controversy exists on the determinants of EI in patients with HFpEF according to case-control studies. The purpose of this study is to systematically review and clarify the main (Fick) determinants of EI in HFpEF., Methods: We conducted a systematic search of MEDLINE, Scopus and Web of Science since their inceptions until January 2017 for articles assessing peak cardiac output and/or arteriovenous oxygen difference (a-vO 2diffpeak ) with incremental exercise in patients diagnosed with HFpEF and age-matched control individuals. Meta-analyses were performed to determine the standardized mean difference (SMD) in peak cardiac index (CI peak ) and a-vO 2diffpeak between HFpEF and control groups. Subgroup and meta-regression analyses were used to evaluate potential moderating factors., Results: Ten studies were included after systematic review, comprising a total of 213 HFpEF patients and 179 age-matched control individuals (mean age=51-73years). After data pooling, CI peak (n=392, SMD=-1.42; P<0.001) and a-vO 2diffpeak (n=228, SMD=-0.52; P=0.002) were impaired in HFpEF patients. In subgroup analyses, a-vO 2diffpeak was reduced in HFpEF versus healthy individuals (n=114, SMD=-0.85; P<0.001) but not compared with control patients without heart failure (n=92, SMD=-0.12; P=0.57). The SMD in a-vO 2diffpeak was negatively associated with age (B=-0.05, P=0.046), difference in % females (B=-0.01, P=0.026) and prevalence of hypertension (B=-0.01, P=0.015) between HFpEF and control groups., Conclusions: HFpEF is associated with a predominant impairment of CI peak , accompanied by sex- and comorbidity-dependent reduced oxygen extraction at peak exercise., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The marine environment acts as a sink for diverse anthropogenic pollutants, although the environmental contamination may be non-uniformly distributed. In recent decades, the aquaculture sector has experienced a steady growth postulating as a good alternative for seafood production. However, a social debate exits about the differential level of pollutants in wild and farmed species. This study was designed to evaluate the level of pollutants in a sentinel species: Bogue (Boops boops) associated and non-associated to fish-farm cages. A total of 82 chemical substances were determined by gas chromatography-mass spectrometry, including persistent (polychlorobiphenyls (PCBs) and organochlorine pesticides (OCPs)), semi-persistent (bromodiphenyl ethers (BDEs) and polycyclic aromatic hydrocarbons (PAHs)), and emerging pollutants (such as organophosphate flame retardants (OPFRs) and UV-filters). In general, aquaculture-associated bogues showed lower levels of semi-persistent and emerging pollutants than wild-caught fish, especially when sums were considered. Thus, sum of BDEs was significantly lower in the aquaculture group (p=0.01). A similar trend was also observed for benzo(a)anthracene, the UV-filter 2-ethylhexyl-p-methoxycinnamate and some OPFRs. In the case of persistent pollutants, the sum of dioxin-like PCBs and sum of DDTs were lower in the group of wild-caught bogues (p=0.034 and p=0.003, respectively) than in aquaculture-associated bogues, as previously described for some aquaculture species. Fish feed appear as an important factor in the uptake of such substances suggesting a diet intervention to reduce their levels in the aquaculture products. Another interesting result is that for almost all chemical substances analyzed, bogues captured near sewage outfalls showed the highest levels of pollutants, pointing out the need of stringent measures for wastewater treatment units discharging in coastal areas. On the light of these results, further research in specific farmed and wild fish species in relation to their dietary value and pollutant's levels seems to be mandatory., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background: Erythropoiesis is partly regulated through classic feedback pathways that govern blood volume (BV) as sensed by veno-atrial but also arterial stretch receptors. Hence, the total volume of red blood cells (RBCV) could be associated with arterial stiffness (AS), although such hypothesis has not yet been tested. Therefore, we sought to investigate the association of AS with hematological variables including RBCV., Methods: Fourteen healthy physically active individuals volunteered for the study (age=23±2). RBCV, plasma volume (PV), and BV were calculated from measures of hematocrit and total hemoglobin mass (Hbmass) determined by CO-rebreathing. Carotid compliance with ultrasonography and carotid-ankle pulse wave velocity (PWV) were determined at rest and immediately after a maximal exercise test. The rationale for assessment of AS after exercise derives from the potential marked role of AS in the regulation of erythropoiesis in the setting of reduced central venous pressure., Results: At rest, carotid compliance was positively associated with Hbmass, RBCV, BV, but not PV, with coefficients of determination (R(2)) ranging from 0.39 to 0.57. Following exercise, closer positive associations were observed between carotid compliance and Hbmass, RBCV, or BV. Moreover, carotid-ankle PWV was negatively associated with all hematological variables after exercise except for PV, with R(2) ranging from 0.49 to 0.75. Similar results were observed when adjusted by body weight., Conclusions: AS is strongly and inversely associated with RBCV in healthy individuals. These findings suggest that AS may adversely intercede in the regulation of erythropoiesis through the alteration of mechanisms that control BV., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Introduction: Whilst the relationship between lipids and cardiovascular mortality has been well studied and appears to be controversial, very little has been explored in the context of rural-to-urban migration in low-resource settings., Objective: Determine the profile and related factors for HDL-c patterns (isolated and non-isolated low HDL-c) in three population-based groups according to their migration status, and determine the effect of HDL-c patterns on the rates of cardiovascular outcomes (i.e. non-fatal stroke and non-fatal myocardial infarction) and mortality., Methods: Cross-sectional and 5-year longitudinal data from the PERU MIGRANT study, designed to assess the effect of migration on cardiovascular risk profiles and mortality in Peru. Two different analyses were performed: first, we estimated prevalence and associated factors with isolated and non-isolated low HDL-c at baseline. Second, using longitudinal information, relative risk ratios (RRR) of composite outcomes of mortality, non-fatal stroke and non-fatal myocardial infarction were calculated according to HDL-c levels at baseline., Results: Data from 988 participants, rural (n = 201), rural-to-urban migrants (n = 589), and urban (n = 199) groups, was analysed. Low HDL-c was present in 56.5% (95%CI: 53.4%-59.6%) without differences by study groups. Isolated low HDL-c was found in 36.5% (95%CI: 33.5-39.5%), with differences between study groups. In multivariable analysis, urban group (vs. rural), female gender, overweight and obesity were independently associated with isolated low HDL-c. Only female gender, overweight and obesity were associated with non-isolated low HDL-c. Longitudinal analyses showed that non-isolated low HDL-c increased the risk of negative cardiovascular outcomes (RRR = 3.46; 95%CI: 1.23-9.74)., Conclusions: Isolated low HDL-c was the most common dyslipidaemia in the study population and was more frequent in rural subjects. Non-isolated low HDL-c increased three-to fourfold the 5-year risk of cardiovascular outcomes., (Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.)

Background: While aerobic exercise training may decrease arterial stiffness, the impact of combined aerobic and resistance training is unclear. Therefore, the aim of this study was to systematically review and quantify the effect of combined aerobic and resistance training on arterial stiffness, as determined by arterial pulse wave velocity (PWV), and compare it with aerobic training., Methods: MEDLINE, EMBASE and Web of Science were searched through November 2013 for randomized controlled trials evaluating the effect of aerobic or combined aerobic and resistance training on PWV. A meta-analysis was performed to determine the standardized mean difference (SMD) in PWV between exercise and control groups. Subgroup analyses were used to study potential moderating factors., Results: Twenty-one randomized controlled trials comparing exercise and control groups (overall n=752), met the inclusion criteria. After data pooling, PWV was decreased in aerobic trained groups compared with controls (10 trials, SMD=-0.52, 95% CI= -0.76, -0.27; P<0.0001) but did not reach statistical significance in combined trained groups compared with controls (11 trials, SMD=-0.23, 95% CI=-0.50, 0.04; P=0.10). The effect in aerobic trained groups did not differ compared with combined trained groups (P=0.12). In addition, aerobic training resulted in significantly lower SMD in PWV compared with combined training in interventions including a higher volume of aerobic training or assessing carotid-femoral PWV., Conclusions: These data suggest that combined aerobic and resistance training interventions may have reduced beneficial effects on arterial stiffness compared with control interventions, but do not appear to differ significantly with aerobic training alone., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: Debate concerning aerobic exercise decreasing arterial stiffness in pre- and hypertensive individuals still exists. We sought to systematically review and quantify the effect of aerobic exercise training on arterial stiffness in pre- and hypertensive subjects., Methods: MEDLINE, Cochrane, Scopus and Web of Science were searched up until August 2013 for trials assessing the effect of aerobic exercise interventions lasting 4 or more weeks on arterial stiffness in (pre)hypertensive subjects. Standardized mean difference (SMD) in arterial stiffness parameters (PWV, B-stiffness, Compliance, AIx) was calculated using a random-effects model. Subgroup and meta-regression analyses were used to study potential moderating factors., Results: Fourteen trials comprising a total of 472 (pre)hypertensive subjects met the inclusion criteria. Arterial stiffness was not significantly reduced by aerobic training in (pre)hypertensive subjects (14 trials, SMD=-0.19; P=.06). Likewise, post-intervention arterial stiffness was similar between the aerobic exercise-trained and control (pre)hypertensive subjects (8 trials, SMD=-0.10; P=.43). Neither heterogeneity nor publication bias was detected in either of these analyses. In the subgroup analyses, arterial stiffness was significantly reduced in aerobic exercise-trained (pre)hypertensive subgroups below the median value in post minus pre-intervention systolic blood pressure (SBP) (SMD=-0.38, P=.04) and in subgroups above the median value in the duration of the intervention (SMD=-0.28, P=.03). Similar results were obtained in the meta-regression analysis., Conclusions: Arterial stiffness is not reduced in (pre)hypertensive subjects in response to aerobic training unless associated with a substantial reduction in SBP and/or prolonged duration., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Objective: This study was undertaken to test the hypothesis of an association between pharmacologic agents used for labor induction, in particular dinoprostone, and postpartum disseminated intravascular coagulation (DIC)., Study Design: A retrospective hospital-based case-control study. Adjusted odds ratios (AOR) were calculated by a conditional logistic regression., Results: Forty valid cases of postpartum DIC were compared against 197 matched controls. Labor was induced in 17% of controls, and 56% of cases (AOR = 7.2; 95% CI: 2.1-24.6). The association was observed for both dinoprostone (AOR = 6.7; 95% CI: 1.7-26.5) and oxytocin (AOR = 8.4; 95% CI: 1.4-50.9). Other risk factors identified were as follows: a maternal age older than 34 years (AOR = 9.5; 95% CI: 2.4-37.7), complications during pregnancy (AOR = 5.5; 95% CI: 1.3-22.8), and a gestational age of over 40 weeks (AOR = 3.5; 95% CI: 1.1-11.1). Such factors were shown to also have an interaction with the induction of labor. Oxytocin augmentation showed a negative association (AOR = 0.1; 95% CI: 0.02-0.4). The absolute risk attributable to induction was estimated in 5 per 10,000 deliveries., Conclusion: The pharmacologic induction of labor is associated with an increased risk of postpartum DIC, regardless the substance used. Although the absolute risk seems to be quite low, the obstetricians should not neglect it, in particular for the special risk groups identified.

Several antidepressant drugs were given to pregnant rats in the last 15 days of gestation and 3H-imipramine binding (3H-IMI) was subsequently measured in the cerebral cortex of the offspring. The selective serotonin (5-HT) uptake blockers chlorimipramine and fluoxetine as well as the selective monoamine oxidase (MAO) inhibitors clorgyline and deprenyl induced, after prenatal exposure, a down-regulation of 3H-IMI binding sites at postnatal day 25. The density of these binding sites was still reduced at postnatal day 90 in rats exposed in utero to the MAO inhibitors. The antidepressants desipramine and nomifensine were ineffective in this respect. After chronic treatment of adult animals, only chlorimipramine was able to down-regulate the 3H-IMI binding sites. Consequently, prenatal exposure of rats to different antidepressant drugs affecting predominantly the 5-HT systems induces more marked and long-lasting effects on cortical 3H-IMI binding sites. The results suggest that the developing brain is more susceptible to the actions of antidepressants.

We studied the effect of alpha-1 and alpha-2 blockers (prazosin and yohimbine) on systolic blood pressure (SBP) and on renal norepinephrine (NE) content in Sprague-Dawley normotensive and DOCA-salt rats. The administration of desoxycorticosterone acetate (DOCA) to these rats for 6 weeks increased their SBP from 137 to 183 mmHg (p less than .001). This increase was prevented by simultaneous administration of prazosin (p less than .001), yohimbine (p less than .01), or prazosin + yohimbine (p less than .001). DOCA rats on saline and on yohimbine had lower renal NE content (p less than .05 and p less than .001, respectively) than normotensive rats. Renal NE content of DOCA rats on yohimbine decreased with respect to those treated with prazosin (p less than .001) or prazosin + yohimbine (p less than .05). Besides, renal NE content of DOCA rats on prazosin increased when compared to control DOCA rats (p less than .05). However, these drugs showed no effect on SBP and on renal NE content in normotensive rats. These findings further confirm that the alpha adrenoceptor blockade can prevent the hypertension of DOCA-salt rats in such a way that their blood pressure stabilizes at similar levels to those observed in normotensive treated animals.

Platelet 3H-imipramine binding, platelet serotonin content, and plasma cortisol were measured in 10 healthy female volunteers. Samples were taken on 5 occasions with a 6-hr interval during a 24-hr period within 1 week in May. Although there were individual variations in the biochemical parameters over a 24-hr period, we could not establish a clear common circadian rhythm for all subjects in platelet 3H-imipramine binding and platelet serotonin concentrations. During the night, there was a significant decrease in Bmax values and a slight, but not significant, increase in serotonin concentrations. A distinct circadian rhythm was obtained for plasma cortisol, with lowest values during the night.