C. Perillan

C-reactive protein is elevated in the offspring of parents with essential hypertension

Background: Hypertension is a risk factor for cardiovascular disease (CVD). Studies in adults have shown that high sensitivity C-reactive protein (CRP) levels are associated with increased risk of CVD and essential hypertension (EHT). Genetic background is widely accepted as a risk factor for CVD. The aim of the present study was to analyse the association of high sensitivity CRP levels with other cardiovascular risk factors in children and young adults with at least one parent with EHT. Methods: Fifty one healthy children and young adults (28 boys) with at least one parent with hypertension and 69 (41 boys) whose parents did not have hypertension were recruited prospectively from primary care centres. High sensitivity CRP, fasting lipid profile, blood pressure (BP) and anthropometric variables were obtained for all participants. Results: CRP values were higher in the study group than in controls (logCRP mean difference: −0.69; 95% confidence interval: −1.05 to −0.33), even when differences were adjusted for age, gender, body mass index (BMI) and triglyceride levels (p = 0.01). No differences were observed in BP values between groups. In the study group, 35.3% of the participants had a CRP level ⩾1 mg/l compared to 14.5% in the control group (p = 0.009). CRP showed a significant correlation with body weight (rho = 0.28, p = 0.04), BMI (rho = 0.32; p = 0.02) and ponderosity index (rho = 0.28; p<0.05). Conclusions: CRP is significantly higher in the offspring of parents with EHT. A significant positive relationship exists between BMI and serum CRP levels in this high risk group of children and young adults.

Thirst changes in offspring of hyperreninemic rat dams

The aim of this study was to investigate the changes in thirst dependence on the renin-angiotensin system (RAS), in offspring of hyperreninemic, hyperdipsic, and natriophilic rat dams. Female rats underwent a partial aortic ligature between the renal arteries (PAL) or were sham-operated (SHAM). At 6 days of age, offspring of PAL (O-PAL) and SHAM (O-SHAM) dams were injected with isoproterenol (subcutaneously, 500 microg/kg body weight) or vehicle. Pretreatment with captopril (intraperitoneally, 50 mg/kg) on isoproterenol-induced thirst was also studied. Plasma renin activity in dams and hematocrit and osmolality in pups were measured. O-PAL had a greater water intake than O-SHAM. However, they responded similarly to isoproterenol or isoproterenol with captopril pretreatment. Only minor differences in hematocrit and osmolality were found between O-SHAM and O-PAL rats after isoproterenol or vehicle treatment. Beta-adrenergic or angiotensinergic responsivity seems not to be altered in offspring of hyperrenimic, hyperdipsic, and natriophilic dams. Nevertheless, other thirst responses of offspring may be critically dependent upon uterine conditions.

Maternal RAS influence on the ontogeny of thirst

Perillan, C., Costales, M., Vijande, M., and J. Arguelles. Maternal RAS influence on the ontogeny of thirst. Physiol Behav XX (X) 000-000, 2006. The main objective of this study was to investigate the effect of an altered ambiance in utero, on the development of thirst mechanisms in the offspring. Female rats underwent a partial ligature of the aorta (PAL), which induces an intrinsic activation of the renin angiotensin system (RAS), thirst and sodium appetite. A second group of female rats was treated with desoxycorticosterone (DOCA) which depresses the RAS. The offspring of these two groups were tested for their responses to several thirst stimuli at 2, 4 and 6 days of age. The offspring from PAL mothers responded like their controls to cellular dehydration (NaCl hypertonic injection) at 2 days of age, and also did to extracellular dehydration by polyethyleneglycol at 4 days. Nevertheless, they responded more to isoproterenol at 6 days of age in comparison to their control group. The offspring from DOCA treated mothers did not show statistically significant responses (in comparison with vehicle injected pups) to hypertonic NaCl at two days nor to polyethyleneglycol at four days. Water intake at 6 days of age after isoproterenol administration in DOCA was statistically enhanced, but not differently from the response obtained from pseudo-DOCA treated pups. In particular, rats developed in a hypereninemic ambiance (O-PAL) during gestation, responded with higher water intake when treated with a strong RAS and thirst activator (isoproterenol) but responded normally to a more gentle and complex stimulus (PG). Therefore it seems that in utero conditions can determine the chronology and intensity of thirst responses in offspring.

Developmental programing of thirst and sodium appetite

Thirst and sodium appetite are the sensations responsible for the motivated behaviors of water and salt intake, respectively, and both are essential responses for the maintenance of hydromineral homeostasis in animals. These sensations and their related behaviors develop very early in the postnatal period in animals. Many studies have demonstrated several pre- and postnatal stimuli that are responsible for the developmental programing of thirst and sodium appetite and, consequently, the pattern of water and salt intake in adulthood in need-free or need-induced conditions. The literature systematically reports the involvement of dietary changes, hydromineral and cardiovascular challenges, renin-angiotensin system and steroid hormone disturbances, and lifestyle in these developmental factors. Therefore, this review will address how pre- and postnatal challenges can program lifelong thirst and sodium appetite in animals and humans, as well as which neuroendocrine substrates are involved. In addition, the possible epigenetic molecular mechanisms responsible for the developmental programing of drinking behavior, the clinical implications of hydromineral disturbances during pre- and postnatal periods, and the developmental origins of adult hydromineral behavior will be discussed.

In utero extracellular dehydration modifies thirst in neonatal rats.

The main aim of this study was to investigate the effect of maternal extracellular dehydration during pregnancy in rats on the development of thirst mechanisms in the offspring. Pregnant rats underwent three episodes of extracellular dehydration induced by injecting s.c. 15ml/kg b.w. of a 20% wt/vol solution of polyethylene glycol (PEG) in saline. The treatment given on days 14, 17 and 20 postconception is thought to induce endocrine and natriophilic responses similar to those elicited by vomiting. The offspring were tested for their responses to three different thirst stimuli at 2, 4 and 6 days of age. Like the controls, the offspring from PEG-treated mothers responded to beta stimulation by isoproterenol at 6 days of age. However, they failed to respond to cellular dehydration (NaCl hypertonic injection) at 2 days of age or to extracellular dehydration by PEG on day 4. In conclusion, offspring exposed to in utero extracellular dehydration do not respond to cellular dehydration at 2 days of age or to extracellular dehydration at 4 days of age, whereas control pups had already developed an appropriate response to these stimuli. According to these results, it therefore seems that in utero conditions determine the development of adaptive thirst responses in offspring.

Progressive training effects on neuronal hypothalamic activation in the rat.

The purpose of this study was to examine whether progressive training exercise resulted in changes in neuronal expression of c-Fos in the hypothalamic regions (paraventricular nucleus, supraoptic nucleus and suprachiasmatic nucleus) and subfornical organ of Wistar rats and its relation to hydromineral parameters such as plasma proteins, osmolality and hematocrit. Rats were trained progressively in a running wheel over four days, while control rats were not provided with the opportunity to exercise. c-Fos cellular activity was immunohistochemically stained in accordance with the ABC method. The number of c-Fos immunoreactive cells was counted using standard imaging software. c-Fos in the PVN and SO nuclei was found to be significantly increased in trained rats 1h post-exercise compared with control and 24h post-exercise groups. However, no significant differences were found between trained and control rats in the SQ and SFO. These findings provide useful information of interest for future studies on brain specific regions involved in hydromineral balance in response to progressive exercise.

Partial aortic ligature induces selective long-term c-fos like immunoreactivity in the organum vasculosum of the lamina terminalis, medial preoptic area and choroid plexus in the rat

Partial aortic ligature causes an increase in water and sodium intake. Circumventricular brain regions are known to be involved in the regulation of these processes. In this work we use c-fos-like immunoreactivity to detect active areas involved in the long-term control of increased water and sodium intake due to partial aortic ligature. A significant increase in water intake was found on the first day after the induction, while natriophilia was observed on the fourth day. c-fos-like immunoreactivity was found selectively in the subfornical organ, the organum vasculosum of the lamina terminalis, the medial preoptic area, and the choroid plexus of the third ventricle. Present results provide further evidence for the involvement of circumventricular organs and the preoptic area in the regulation of hydromineral balance. Moreover, they suggest a maintained and long-term regulation of sodium intake by these same brain areas.

Circadian urinary citrate excretion in a rat model of exercise

Aims: Circadian rhythms are the approximate 24 h biological cycles that function to prepare an organism for daily environmental changes. Circadian rhythms unquestionably play critical roles in metabolic homeostasis and the exercise has emerged as a strong non‐photic time cue or zeitgeber in animal models and humans. Numerous studies about the effects of exercise on the citrate synthase activity have been published. Citrate is used to assess energy production or expenditure because it is a substrate of the Krebs Cycle, a cycle for oxidative energy production. Main methods: We tested the existence of a rhythmic urinary citrate excretion in a rat model that is made to exercise at six different points during the day. Key findings: The data obtained by the enzyme assays were fitted to a mathematical model (Fourier series), showing for the first time, the existence of a distinct ultradian rhythm in the urinary citrate excretion. The aerobic exercise led to the increase in the period length of the ultradian rhythm and raised the acrophase value of the urinary citrate excretion. Therefore, the urinary citrate excretion pattern changed after exercise, showing a clear circadian rhythm fitted to the mathematical model. Significance: The citrate urine samples could provide accurate data for ranking an individuals metabolic status. Using exercise to maintain the circadian clock at an appropriate phase and amplitude might be effective to prevent cardiometabolic disease development.

The effects of experimental gestational hypertension on maternal blood pressure and fluid intake and pre-weanling hypothalamic neuronal activity

To examine the fetal programming effects of maternal hypertension, natriophilia and hyperreninemia [experimentally induced in rats by partial inter-renal aortic ligature (PAL) prior to mating] fos immunoreactivity was studied in 6-day-old offspring of PAL and control mothers. The purposes of the present set of experiments were twofold. The first was to characterize the effects of PAL on the mothers arterial blood pressure and intake of salt (1.8% NaCl solution) and water over the course of gestation. Second, was to study the pattern of neuronal activation in key brain areas of 6-day-old offspring treated with the dipsogen isoproterenol that were from PAL and control mothers. Beta-adrenergic receptor agonist-treated pups allowed the determination whether there were neuroanatomical correlates within the neural substrates controlling thirst and the enhanced water intake evidenced by the isoproterenol treated pups of PAL mothers. Hydromineral ingestive behavior along with blood pressure and heart rate of PAL (M-PAL) and control (M-sPAL) dams throughout gestation was studied. Higher salt and water intakes along with blood pressures and heart rates were found during gestation and lactation in the M-PAL group. Maternal PAL evoked significantly increased isoproterenol-elicited Fos staining in brain regions (e.g. subfornical organ, organum vasculosum of the lamina terminalis, supraoptic nucleus, hypothalamic paraventricular nucleus and median preoptic nucleus) of 6-day-old pups, which is the age of animals shown enhanced thirst responses in PAL offspring. These results indicate that PAL is compatible with pregnancy, producing a sustained increase in blood pressure and heart rate, along with increased water and salt intake. The present study demonstrates that the neural substrates involved in cardiovascular homeostasis and fluid balance in adult rats are responsive in six-day-old rats, and can be altered by fetal programming.

Adaptación y aplicación del cuestionario CLASS (Colorado Learning Attitudes about Science Survey) para la valoración de actitudes y creencias científicas en alumnos de enseñanza secundaria y universitaria

espanolIntroduccion. La evaluacion de conocimientos y habilidades ha sido objeto de estudio durante muchos anos; sin embargo, la valoracion de las actitudes requiere un abordaje diferente. Objetivo. Utilizar una herramienta metodologica sencilla (cuestionario CLASS-Bio) que permita comparar la evolucion de las percepciones acerca de la disciplina de biologia y fisiologia de los estudiantes noveles, comparandola con las de estudiantes de cursos superiores, con el fin de poder analizar la influencia de la docencia sobre estas percepciones y actitudes. Sujetos y metodos. Los participantes fueron 288 estudiantes, pertenecientes a dos grupos: un grupo de bachillerato (41 alumnos de primero y 59 de segundo curso) y un grupo de universitarios de primer curso (92 alumnos de enfermeria, 53 de fisioterapia y 25 de logopedia). La puntuacion favorable representa el porcentaje en que el estudiante contesta como experto. Resultados. Los resultados fueron mas proximos a los obtenidos por el grupo de expertos en segundo curso de bachillerato, con un desplazamiento hacia la mejoria, comparado con los obtenidos en el curso anterior. Las respuestas de grupos de universitarios de enfermeria y fisioterapia arrojaron resultados similares, evolucionando hacia unas percepciones mas proximas a las de los expertos, y al mismo tiempo bastantes diferentes a las obtenidos con los alumnos de logopedia. Conclusiones. La adaptacion al castellano del cuestionario CLASS-Bio puede utilizarse como herramienta metodologica valida para valorar el proceso continuo de ensenanza-aprendizaje y evaluar la influencia de la docencia sobre las creencias y actitudes de los estudiantes. EnglishIntroduction. Over the last years, evaluation of knowledge and attitudes in biology education has received a strong call to improve. Aim. To use an easy methodological tool (CLASS-Bio questionnaire) that allows measuring novice-to-expert-like perceptions evolution about Biology and/or Physiology disciplines. In this way, we will be able to analyze the influence over the perceptions and attitudes. Subjects and methods. The participants were 288 students distributed in two groups: a group of high school students (41 of senior secondary school, 1st course; and 59 of senior secondary school, 2nd course), and another one of undergraduate students (1st year): 92 of Nursing Degree, 53 of Physiotherapy Degree and 25 of Speech Therapist Degree. The favorable rating is quantified by comparing students’ responses with a consensus expert response. Results. The 2nd senior secondary school students’ results were more similar to the expert responses than the 1st senior secondary school students; this displacement or shifts indicated an improvement at the 2nd year in the high school. Responses found in the groups of Nursing and Physiotherapy students were similar, evolving closer to the expert perceptions, and quite different compared with the Speech Therapist students responses. It is gratifying to consider how health biosciences students observe these basic subjects more connected to the real world. Conclusions. Spanish adaptation of CLASS-Bio questionnaire could be used as an accessible methodological tool in order to analyze the continuous evolution of teaching and learning process at different academic stages.