Effect of a gradually increasing temperature on the behavioural and physiological response of juvenile Hippocampus erectus: Thermal preference, tolerance, energy balance and growth.

The physiological and behavioural responses of ectotherms to temperature is strongly dependent on the individuals' previous thermal history. Laboratory based studies investigating the mechanisms of thermoregulation in marine ectotherms, however, rarely consider key temporal elements of thermal exposure, such as the rate at which temperature changes. We tested the hypothesis that juvenile seahorses, Hippocampus erectus, from a tropical coastal lagoon in Yucatan, Mexico, would exhibit variations in physiological and behavioural descriptors of thermoregulation when submitted to contrasting regimes during 30 days: temperature constant at 25 °C (C 25); gradually increasing 1 °C every 5 days from 25 to 30 °C (GI 25-30); and constant at 30 °C (C 30). Immediately after exposure, critical maximum temperature, thermal preference, oxygen consumption, partial energy balance, growth rate and survival of seahorses were measured. Seahorses exposed to GI 25-30 showed a significantly higher critical thermal maxima (37.8 ±â€¯0.9 °C), preference (28.7 ±â€¯0.4 °C), growth (1.10 ±â€¯0.49%) and survival (97.6%) than those exposed to C 30 (36.5 ±â€¯1, 29.4 ±â€¯0.3 °C, 0.48 ±â€¯0.32%, 73.8%, respectively). Both high temperature regimes induced metabolic depression, but ramping resulted in a greater amount of energy assimilated (278.9 ±â€¯175.4 J g-1 day-1) and higher energy efficiency for growth (89.8%) than constant exposure to 30 °C (115.4 ±â€¯63.4 J g-1 day-1, 65.3%, respectively). Gradually increasing temperature allowed physiological mechanisms of thermal adjustment to take place, reflecting the capacity of juvenile H. erectus to respond to environmental change. Despite its advantage, this capacity is limited in time, since the cumulative effect of thermal exposure affected metabolic performance, eventually compromising survival. The study of seahorse response to thermal variations in the context of ocean warming needs to consider the temporal elements of thermal exposure to foresee its vulnerability under future scenarios.

Direct evidence of luteal insufficiency in women with habitual abortion.

Plasma levels of progesterone were measured during the luteal phase in 10 of 15 women with clinical histories of at least three spontaneous abortions in the last three gestations, and in 15 healthy nonpregnant women during the same phase of the ovarian cycle. Progesterone values found in the women with habitual abortion were lower (P less than 0.05-0.005) than in the nonpregnant group almost throughout the period of observation. The habitually aborting women who became pregnant again aborted between the seventh and 12th weeks. Their progesterone concentrations were less than 6 ng/ml, 48-72 hours before vaginal bleeding or abortion. These values were compared with those found during the first 12 weeks in normal pregnancy (P less than 0.001). The results suggest a useful method of evaluating the treatment of habitual abortion.

[Postpartum ovarian physiology. Pituitary gonadotropins, estradiol and prolactin during 12 months of postpartum physiology]. / Fisiología ovárica postparto. Gonadotropinas hipofisarias, estradiol y prolactina durante 12 meses a la resolución del embarazo.

In order to establish a relationship between hyperprolactinemia and FSH-LH associated to the ovarian physiology postpartum, a clinical/endocrinological follow-up was performed during a period of twelve months in a cohorte of seventeen women beginning pregnancy resolution. The study had two phases: Lactancy (LAC) and Post-lactancy (LAC) and Post-lactancy (POST-LAC). In both phases blood samples were obtained every week from the first one through the 52nd, to quantitate FSH, LH, prolactin (PRL) and estradiol (E-2). PRL levels were significantly higher during LAC as compared to POST-LAC: an inverse relationship in E-2/PRL was seen through the study. No significant changes for LH and FSH were attained in both phases. Concentrations of these gonadotropins were at the physiological levels and no differences in either one of the two phases were shown when compared to a nonlactating subject. There was a negative association in prolactin levels and the weeks postpartum, and on the contrary, a positive one for E-2. Thus, ovarian follicular development apparently is independent to the gonadotropic-hypophysis stimulus.

Maternal mortality rates in eclampsia.

This study evaluates the dominant factors that influence the course of eclampsia toward a lethal outcome by means of statistical analysis of various clinical, laboratory, and morphologic data of 365 cases of toxemia with convulsions, that included 49 deaths and 33 autopsies, registered during a 9 year period. This communication suggests that the death of eclamptic patients resulted from a combination of several factors that showed a very wide individual variation. Since advancing age of the mother was associated with a high incidence of coincidental renal and vascular diseases, this was the most clearly influential factor. The presence of twins, delay in hospitalization, under haste in deciding upon cesarean delivery, and underestimation of the initial clinical condition were all influential factors, although without statistical significance. Cesarean section, performed in 141 instances of ante- and intrapartum eclasmpsia (40.4 per cent), was not associated with a higher maternal mortality rate.