Exercise training (Ex) has been recommended for its beneficial effects in hypertensive states. The present study evaluated the time-course effects of Ex without workload on mean arterial pressure (MAP), reflex bradycardia, cardiac and renal histology, and oxidative stress in two-kidney, one-clip (2K1C) hypertensive rats. Male Fischer rats (10 weeks old; 150–180 g) underwent surgery (2K1C or SHAM) and were subsequently divided into a sedentary (SED) group and Ex group (swimming 1 h/day, 5 days/week for 2, 4, 6, 8, or 10 weeks). Until week 4, Ex decreased MAP, increased reflex bradycardia, prevented concentric hypertrophy, reduced collagen deposition in the myocardium and kidneys, decreased the level of thiobarbituric acid-reactive substances (TBARS) in the left ventricle, and increased the catalase (CAT) activity in the left ventricle and both kidneys. From week 6 to week 10, however, MAP and reflex bradycardia in 2K1C Ex rats became similar to those in 2K1C SED rats. Ex effectively reduced heart rate and prevented collagen deposition in the heart and both kidneys up to week 10, and restored the level of TBARS in the left ventricle and clipped kidney and the CAT activity in both kidneys until week 8. Ex without workload for 10 weeks in 2K1C rats provided distinct beneficial effects. The early effects of Ex on cardiovascular function included reversing MAP and reflex bradycardia. The later effects of Ex included preventing structural alterations in the heart and kidney by decreasing oxidative stress and reducing injuries in these organs during hypertension.

O objetivo deste estudo foi determinar parâmetros de caracterização da variabilidade da frequência cardíaca (VFC) em indivíduos saudáveis e doentes que permitam a sua discriminação. Os parâmetros usados descrevem as diferentes componentes de memória (curta e longa) da VFC e são calculados por métodos paramétricos e não paramétricos. Assim, foram consideradas as componentes espectrais das baixas frequências (LF) e altas frequências (HF) associadas à memória curta e o parâmetro de memória longa (d) obtidos por modelação autoregressiva de médias móveis integrados fracionariamente (ARFIMA). Analogamente, no contexto não paramétrico, foi utilizado o método detrended fluctuation analysis (DFA) no cálculo dos parâmetros de memória curta (α1) e longa (α2). A amostra foi constituída por 30 registos de 24 horas da base de dados Noltisalis: 10 indivíduos saudáveis, 10 doentes com insuficiência cardíaca e 10 doentes após transplante cardíaco. Observou-se que os parâmetros que caracterizam a memória curta apresentam valores mais elevados para o grupo dos indivíduos saudáveis, enquanto os parâmetros de memória longa têm valores mais elevados para os grupos dos doentes. Concluiu-se que a modelação ARFIMA permite discriminar os 3 grupos de dados em estudo, apresentando vantagens sobre o DFA.

This study aimed to find parameters to characterize heart rate variability (HRV) and discriminate healthy subjects and patients with heart diseases. The parameters used for discrimination characterize the different components of HRV memory (short and long) and are extracted from HRV recordings using parametric as well as non parametric methods. Thus, the parameters are: spectral components at low frequencies (LH) and high frequencies (HF) which are associated with the short memory of HRV and the long memory parameter (d) obtained from autoregressive fractionally integrated moving average (ARFIMA) models. In the non parametric context, short memory (α1) and long memory (α2) parameters are obtained from detrended fluctuation analysis (DFA). The sample used in this study contains 24-hour Holter HRV recordings of 30 subjects: 10 healthy individuals, 10 patients suffering from congestive heart failure and 10 heart transplanted patients from the Noltisalis database. It was found that short memory parameters present higher values for the healthy individuals whereas long memory parameters present higher values for the diseased individuals. Moreover, there is evidence that ARFIMA modeling allows the discrimination between the 3 groups under study, being advantageous over DFA.

We examined the effect of exercise training (Ex) without (Ex 0%) or with a 3% workload (Ex 3%) on different cardiac and renal parameters in renovascular hypertensive (2K1C) male Fisher rats weighing 150-200 g. Ex was performed for 5 weeks, 1 h/day, 5 days/week. Ex 0% or Ex 3% induced similar attenuation of baseline mean arterial pressure (MAP, 119 ± 5 mmHg in 2K1C Ex 0%, N = 6, and 118 ± 5 mmHg in 2K1C Ex 3%, N = 11, vs 99 ± 4 mmHg in sham sedentary (Sham Sed) controls, N = 10) and heart rate (HR, bpm) (383 ± 13 in 2K1C Ex 0%, N = 6, and 390 ± 14 in 2K1C Ex 3%, N = 11 vs 371 ± 11 in Sham Sed, N = 10,). Ex 0%, but not Ex 3%, improved baroreflex bradycardia (0.26 ± 0.06 ms/mmHg, N = 6, vs 0.09 ± 0.03 ms/mmHg in 2K1C Sed, N = 11). Morphometric evaluation suggested concentric left ventricle hypertrophy in sedentary 2K1C rats. Ex 0% prevented concentric cardiac hypertrophy, increased cardiomyocyte diameter and decreased cardiac vasculature thickness in 2K1C rats. In contrast, in 2K1C, Ex 3% reduced the concentric remodeling and prevented the increase in cardiac vasculature wall thickness, decreased the cardiomyocyte diameter and increased collagen deposition. Renal morphometric analysis showed that Ex 3% induced an increase in vasculature wall thickness and collagen deposition in the left kidney of 2K1C rats. These data suggest that Ex 0% has more beneficial effects than Ex 3% in renovascular hypertensive rats.

Our hypothesis is that iron accumulated in tissue, rather than in serum, may compromise cardiovascular control. Male Fischer 344 rats weighing 180 to 220 g were divided into 2 groups. In the serum iron overload group (SIO, N = 12), 20 mg elemental iron was injected ip daily for 7 days. In the tissue iron overload group (TIO, N = 19), a smaller amount of elemental iron was injected (10 mg, daily) for 5 days followed by a resting period of 7 days. Reflex heart rate responses were elicited by iv injections of either phenylephrine (0.5 to 5.0 µg/kg) or sodium nitroprusside (1.0 to 10.0 µg/kg). Baroreflex curves were determined and fitted to sigmoidal equations and the baroreflex gain coefficient was evaluated. To evaluate the role of other than a direct effect of iron on tissue, acute treatment with the iron chelator deferoxamine (20 mg/kg, iv) was performed on the TIO group and the baroreflex was re-evaluated. At the end of the experiments, evaluation of iron levels in serum confirmed a pronounced overload for the SIO group (30-fold), in contrast to the TIO group (2-fold). Tissue levels of iron, however, were higher in the TIO group. The SIO protocol did not produce significant alterations in the baroreflex curve response, while the TIO protocol produced a nearly 2-fold increase in baroreflex gain (-4.34 ± 0.74 and -7.93 ± 1.08 bpm/mmHg, respectively). The TIO protocol animals treated with deferoxamine returned to sham levels of baroreflex gain (-3.7 ± 0.3 sham vs -3.6 ± 0.2 bpm/mmHg) 30 min after the injection. Our results indicate an effect of tissue iron overload on the enhancement of baroreflex sensitivity.

The domestic cat can be defined as a seasonal poliestrous female. During mating the physical stimulus produce the release of LH and ovulation, which occur during the first 50 hours post mating. The fertilization of oocytes takes place inside the oviduct during the 30 hours post ovulation. The embryos transport on the oviduct takes about 132 hours and when embryos reach the uterus they are already a compacted morulae. After this, the blastocyst migrates to both uterine horns for a period of 80 hours aproximately until implantation ocurrs 12 to 13 days after mating. During the preimplantation period, there is a significant increase in blood progesterone and also in LH lutheal receptors. From the second half of gestation, the production of progesterone decrease and prolactin secretion increase. Thus it is thought that the later would be the main luteotrophic agent in the cat. Also during the second half of gestation the secretion of relaxin increase. The production and function of progesterone during late gestation is controversial. It has been shown that placenta of cats has a steroidogenic function and that it is also to produce progesterone

La gata es una hembra poliéstrica estacional en la cual el estímulo coital desencadena la liberación de LH y la ovulación, fenómenos que ocurren dentro de las primeras 50 horas postcoito. La fecundación de los ovocitos ocurre en el oviducto dentro de 30 horas post-ovulación. El transporte embrionario en oviducto toma alrededor de 132 horas y al momento de ingresar al útero los embriones se encuentran al estado de mórula compacta. A continuación los blastocistos migran entre los cuernos uterinos por aproximadamente 80 horas, hasta producirse la implantación 12 a 13 días post-coito. Durante la etapa preimplantacional existe un aumento significativo de la progesterona sérica así como de los receptores luteales a LH. A partir de la segunda mitad de la gestación, decae la producción de progesterona y aumenta la secreción de prolactina, postulándose que esta última sería el principal agente luteotrófico en la gata. También durante la segunda mitad de la gestación aumenta la secreción de relaxina. La producción y rol de la progesterona en la gestación tardía es un tema controversial. Se ha demostrado que la placenta felina posee actividad esteroidogénica y capacidad de sintetizar progesterona, lo cual sugiere que estaría relacionada con el soporte hormonal de la preñez

Day care centers are a relatively new phenomenon in Brazil that bring together large numbers of young children susceptible to contagious diseases. Haemophilus influenzae (Hi) is an important infection in the age range of those attending day care centers. In the present study, the carriage rate of Haemophilus influenzae was identified in 38 day care attendees age 6 to 37 months, and 23 staff members, at a day care center in Ribeirão Preto-São Paulo, in 1997. To identify the carriers, two nasopharyngeal swabs were collected; one in July and one in December. The rate of H. influenzae carriers among the children was 77%. Only 2 of 23 staff members (9%) had Hi. Among the children, there were 58 isolates in the two sampling periods; 6 of the Hi were serotype b, 1 was serotype e, and 48 isolates were non-typeable. Two were identified as H. parainfluenzae. One adult had a non-typeable Hi and 1 had H. paraphrohaemolyticus. Three of the 6 children with type B had received a conjugate vaccine against H. influenzae type b, but they still carried this bacterium in the nasopharynx (50%). Forty ribotype patterns were found among the isolates, showing a high exchange rate of nontypeable H. influenzae carriers. The results indicate that, because of the high and changing biotype of Hi carriage, day care centers should be carefully monitored as potential point source of HI disease in the community.

Estudamos a modulação da resposta inflamatória granulomatosa em torno de ovos de S. mansoni no fígado de camundongos albinos (Mus musculus), que receberam 7% de etanol como única fonte de líquido. Os animais que receberam etanol aos 60 e 90 dias após a infecção apresentaram granulomas menores do que os controles, quando sacrificados aos 120 dias após a infecção. Não houve diferença no diâmetro dos granulomas quando a ingestão de etanol foi iniciada 4 meses antes e prolongada até 120 dias após a infecção. Nossos resultados indicam que a modulação da inflamação granulomatosa varia de acordo com o tempo e a duração da ingestão do etanol.

We studied the role of ethanol on the modulation of liver granulomata around Schistosoma mansoni eggs in mice. Albino mice, receiving 7% ethanol as the sole drinking liquid, at 60 and 90 days post-infection, presented smaller granulomata than controls did, when sacrificed at 120 days post-infection. No differences in diameters could be observed, when ethanol was given 4 months before up to 120 days after infection. The results suggested that modulation of schistosome granulomata by ethanol ingestion varies with time and duration of drug consumption.