Variability in reproductive success viewed from a life‐history perspective in baboons

Nonhuman primates, like humans, mature slowly and have low fertility during a relatively long life. As data have accumulated on life‐history patterns of nonhuman primates, comparative studies have yielded important insights into the evolution of this slow life‐history style of primates. However, in order to understand selection pressures and evolutionary potential within species, it is important to complement comparative studies with detailed studies of life‐history variability within species and to identify sources of this variability. Here we present a summary of how foraging environment, social status, and group size (a measure of population density) contribute to within‐population variance in reproductive success for savannah baboons. We also discuss the extent to which savannah baboons, with their highly flexible and adaptable behavior, change their foraging environments by shifting home ranges and seeking rich food sources and how low‐ranking females, which disproportionately bear the costs of social life, may mitigate those costs. Am. J. Hum. Biol. 15:401–409, 2003. © 2003 Wiley‐Liss, Inc.     

Variability in ratings of trustworthiness across the menstrual cycle

This study investigated how trusting behavior varies in naturally cycling women, as a function of sex and attractiveness of players in a trust game, at three distinct phases of the menstrual cycle. Women acted more cautiously in an investment game at the preovulatory phase, compared to the menstrual and the mid-luteal phase. Reduced willingness to trust in strangers was particularly expressed toward male players at this time. The increase of estradiol levels from menses to the preovulatory phase was negatively correlated with trust in attractive male other players, whereas the increase of progesterone levels from menses to the mid-luteal phase was positively associated with trust in unattractive female other players. No particular contribution of a single hormone level could be identified for the generally reduced willingness to trust in strangers in the preovulatory phase. Thus, the results emphasize the impact of the menstrual cycle on interpersonal trust, although the exact mode of hormonal action needs to be further investigated.     

Placentophagia in rabbits: incidence across the reproductive cycle

Rabbits show placentophagia at parturition, but the regulation of this behavior and its incidence across the reproductive cycle are unknown. By testing estrous, midpregnant, prepartum (day 1), and postpartum (days 1 and 5) food-deprived rabbits with liver and placenta, we found an absence or infrequency (<%) of placentophagia in the former three groups, an invariable occurrence at parturition, and a persistence into postpartum days 1 and 5 (50 and 48%, respectively). Most placentophagic females also ate liver on postpartum day 1, but not on postpartum day 5. In different food-deprived rabbits, tested every 2 hr with placenta and food pellets, placentophagia incidence was 20% at 8 hr prepartum, 100% at parturition, and 67 and 21% at 8 and 24 hr postpartum, respectively. Most placentophagic rabbits also ate food pellets in postpartum (but not in prepartum) tests. Results suggest that somatosensory, hormonal, or both factors of the peripartum period regulate placentophagia expression.     

Systematic review of gamma-aminobutyric-acid inhibitory deficits across the reproductive life cycle

Deficiencies in the inhibitory functioning of gamma-aminobutyric acid (GABA) have been implicated in the pathophysiology of depressive disorders. Reproductive life cycle events, including menstruation, pregnancy, and menopause, are consistently associated with increased psychopathology, in particular mood disorders. Given that GABA-inhibitory activity may be modulated directly or indirectly by estrogen, progesterone, and their metabolites receptors, it has been hypothesized that GABA deficits may be evident during these reproductive periods. We aimed to compare GABA function among women during these “high-risk” reproductive periods to GABA function among women at other time periods. We conducted a systematic review of studies comparing women during reproductive life stages associated with depressive disorder risk (luteal phase of the menstrual cycle, perinatal period, and menopausal transition) to women at other time periods. The study outcome was GABA function. The review included 11 studies, 9 focused on the menstrual cycle, and 2 focused on the perinatal period. GABA-inhibitory function fluctuated across the menstrual cycle, with differing patterns in women with and without depressive disorders. GABA-inhibitory function was reduced in pregnancy and early postpartum compared to the nonpregnant state. Key limitations were the absence of studies evaluating the menopausal transition, and the heterogeneity of GABA outcome measures. GABA-inhibitory function fluctuates across the menstrual cycle and is reduced perinatally. This has potential implications for a role of GABAergically mediated interventions in the prevention and treatment of menstrual cycle-related and perinatal depressive disorders.     

Spermatozoal nuclear determinants of reproductive outcome: implications for ART

A male factor is implicated in more than 50% of couples treated with IVF. However, neither the routine testing of male fertility potential nor its treatment address the specific mechanisms by which spermatozoal factors may impact upon reproductive outcome. An important function of spermatozoa is to deliver the paternal genome to the oocyte. Recently, a number of acquired spermatozoal nuclear factors that may have implications on reproductive outcome have been described. These include non-specific DNA strand breaks, numerical abnormalities in spermatozoal chromosome content, Y chromosome microdeletions and alterations in the epigenetic regulation of paternal genome. The exact mechanisms by which these factors affect reproduction are unknown and their implications for assisted reproduction technology outcome need to be further investigated. These recent findings point to the need for novel and more personalized approaches to test and treat male factor infertility.     

The septal social cohesiveness effect: its robustness and main determinants

Rats prepared with lesions of the forebrain septum and placed within an open field exhibit strong tendencies to maintain contacts with each other. The expressed doubts of other workers notwithstanding, the effect is robust and enduring, as is shown by an experiment with one pair of rats and a review of past experiments. Moreover, although septal rats are fearful when alone within a field, they will actively approach cats or rabbits, which suggests that the effect is primarily a function of release of the contact-comfort motive.     

低出生体重儿的发生与母亲既往生育史的相关性分析

目的探讨母亲既往生育史对单胎活产低出生体重儿发生的影响因素。方法选取375名住院产妇所生的单胎活产低出生体重儿（LBW）,与同期分娩的单胎活产正常体重儿5157例进行病例对照分析,比较母亲既往生育史对低出生体重儿发生的影响。结果既往自然流产史、早产史和不良孕产史是LBW发生的危险因素（OR=1.57 95%CI1.110-2.25）、（OR=4.84 95%CI 2.01-11.66）、（OR=2.09 95%CI 1.22-3.57）,并且主要针对于早产LBW（OR=1.6595%CI 1.11-2.44）、（OR=6.55 95%CI 2.70-15.91）、（OR=2.18 95%CI 1.21-3.91）,既往低出生体重史是足月LBW发生的危险因素（OR=7.93 95%CI 1.72-36.46）结论 LBW的发生与既往自然流产史、早产史、不良孕产史、低出生体重史密切相关。对以上这些妇女再次怀孕的孕前、孕期均应做好保健服务,以有效减少LBW的发生。     

Galactose metabolism and reproductive history in women with type 1 neurofibromatosis

To explore a possible relationship between neurofibromatosis and abnormalities of galactose metabolism, we examined the activity and characteristics of red cell galactokinase and galactose-1-phosphate uridyl transferase in 14 white women with type 1 neurofibromatosis and in 28 control women. Women with NF1 had a significantly lower activity of galactokinase and were more likely to have the 3-band pattern on electrophoresis of their transferase enzyme known as the Duarte variant. In addition, we found that women with NF1 were more likely to have reproductive histories suggestive of hypogonadism, including irregular menses, infertility, ovarian cysts, and early menopause. We conclude that abnormalities of galactose metabolism may be linked to abnormalities of both germ cell and neural crest development.     

The effect of reproductive history on future pregnancy outcomes.

The aim of this study was to examine the separate and joint effects of previous pregnancy history, year of pregnancy outcome, maternal age, height, smoking and fertility on risk of fetal death. Data were available from a study of female radiographers. Analyses were carried out on 3053 women with a total of 6993 pregnancies. Women reporting problems with conception or previous fetal losses had an increased risk of a pregnancy ending in a fetal death. In particular, women with primary or secondary infertility had an approximately fourfold increase in risk compared with women who reported no difficulties [odds ratio (OR): 3.92; 95% confidence interval (CI): (3.02, 5.07)]. This relationship was independent of pregnancy order and pregnancy history and was more marked in older maternal ages. The effect of pregnancy history was cumulative and possibly multiplicative in effect, with a threefold increase in the risk of losing a third pregnancy following two previous losses [OR: 3.19; 95% CI: (1.60, 6.35)]. There were no consistent patterns of risk associated with year of pregnancy outcome, maternal age, height or smoking status. These results suggest that previous pregnancy outcomes and problems with conception may be the strongest determinants of fetal loss in subsequent pregnancies.     

Systemic mechanisms of individual reproductive life history in female Medflies

This paper is the second one in a series of two papers hypothesizing and testing systemic grounds of reproductive life history in the female fruit fly. In the first paper, we analyzed mechanisms of individual fecundity scheduling and have drawn the following conclusions. Individual fecundity in female flies is endowed as a flat pattern with a steady-state period of a constant rate of egg-laying. An individual female reveals three stages in her adult life history: maturation, maturity, and senescence. The first stage is a transient period of achieving a steady state at maturity, which can be maintained until the senescence stage. Thus, an individual fecundity pattern has no maximum. The maximums observed experimentally are averaging-caused artifacts. Two natural causes of deaths exist in flies, senescence-caused ones and premature deaths, probably due to a reproductive overload. In this paper, to confirm these findings, we use individual daily scores of egg-laying in four populations of Mediterranean fruit flies. Based on fecundity scores, we divide each Medfly population into four classes, namely zero-egg, short-, medium- and long-lived egg-layers. We demonstrate that, indeed, the three above findings definitely exist in Medflies. Our procedure allows the efficient storage of individual fecundity in parametric form, with only five numbers for each fly. Finally, this protocol will allow a more precise analysis of fecundity-energy trade-offs in flies carrying appropriate longevity mutations.     

A phenotypic in vitro model for the main determinants of human whole heart function

This article details the construction and testing of a phenotypic assay system that models in vivo cardiac function in a parallel in vitro environment with human stem cell derived cardiomyocytes. The major determinants of human whole-heart function were experimentally modeled by integrating separate 2D cellular systems with BioMicroelectromechanical Systems (BioMEMS) constructs. The model features a serum-free defined medium to enable both acute and chronic evaluation of drugs and toxins. The integration of data from both systems produced biologically relevant predictions of cardiac function in response to varying concentrations of selected drugs. Sotalol, norepinephrine and verapamil were shown to affect the measured parameters according to their specific mechanism of action, in agreement with clinical data. This system is applicable for cardiac side effect assessment, general toxicology, efficacy studies, and evaluation of in vitro cellular disease models in body-on-a-chip systems.     

The role of maternal reproductive history in the aetiology of neural tube defects.

The contribution of environmental factors to the aetiology of neural tube defects (NTD) has been stressed over recent years and many different risk factors have been proposed. We evaluated the reproductive history of 113 NTD cases to investigate the possible role of maternal age, gestational age, sex, parity and previous pregnancy. Our results show that parity and previous spontaneous abortion can be considered as risk factors for NTD and that an accurate evaluation of reproductive history can be useful for genetic counselling. The known benefits of periconceptional intervention in reducing the incidence of NTD in high risk populations, together with our results, means that mothers with a positive reproductive history for spontaneous abortion and for multiparity are ideal subjects for folic acid periconceptional management.