Disappearance of the ovulation stigma in baboons (Papio anubis, Papio cynocephalus) as determined by serial laparoscopies during the luteal phase

OBJECTIVE: To investigate how long an ovulation stigma remains visible as determined by serial laparoscopies performed during the luteal phase in baboons. SUBJECTS AND SETTING: Sixteen female baboons with a normal pelvis (n = 6) and with endometriosis (n = 10) housed at the Institute of Primate Research, Nairobi, Kenya. INTERVENTIONS: Fifty-six laparoscopies were carried out before ovulation (n = 7) and serially during the luteal phase (n = 49; 3 +/- 1 per baboon): 1 to 2 days (n = 2), 4 to 5 days (n = 15), 8 to 9 days (n = 11), 12 to 13 days (n = 12), and 16 to 17 days (n = 9) after ovulation. MAIN OUTCOME MEASURE: During each laparoscopy the ovaries were screened systematically for the presence and size of an ovulation stigma and/or corpus luteum (CL). RESULTS: When the laparoscopy was done within 5 days after ovulation, a fresh ovulation stigma was observed in all nine baboons with a normal pelvis or minimal endometriosis, but only in four of seven animals with mild to severe disease. If a fresh ovulation stigma had been observed within 5 days after ovulation (n = 13), it gradually became smaller but remained visible 8 to 9 days after ovulation in 91%, at 12 to 13 days after ovulation in 75%, and at 16 to 17 days after ovulation in 50% of the primates. CONCLUSION: If a fresh ovulation stigma was observed in baboons within 5 days after ovulation, it diminished in size but remained visible up to 8, 12, and 16 days after ovulation in 91%, 75%, and 50% of animals, respectively. Therefore, diagnostic laparoscopies for the detection of an ovulation stigma in baboons should be performed in the early luteal phase.     

Serial laparoscopies over 30 months show that endometriosis in captive baboons (Papio anubis, Papio cynocephalus) is a progressive disease

OBJECTIVE: To test the hypothesis that spontaneous endometriosis is a progressive disease in baboons. DESIGN AND SETTING: Prospective cohort study, Institute of Primate Research, Nairobi, Kenya. PARTICIPANTS: Twelve baboons with histologically proven spontaneous endometriosis. INTERVENTIONS: Fifty-four serial laparoscopies (4.2 +/- 1.9 per animal, range 1 to 7) were performed after 1 to 3 months (n = 2), 4 to 6 months (n = 1), 7 to 9 months (n = 6), 10 to 12 months (n = 17), 13 to 15 months (n = 7), 16 to 18 months (n = 1), 19 to 21 months (n = 8), 22 to 24 months (n = 8), 25 to 27 months (n = 2), and 30 to 32 months (n = 2). MAIN OUTCOME MEASURE: During each laparoscopy the pelvis was examined for the presence of endometriosis. The number, size, and type of endometriotic implants were noted on a pelvic map and both endometriosis score and stage were calculated. Remodeling was defined as a change in laparoscopic appearance (typical, subtle, suspicious) of an individual endometriotic lesion. Data were analyzed by a signed rank test. RESULTS: Endometriosis was progressive as shown by the significant increase in the number and surface of lesions and in endometriosis scores after 24 months. The total number of endometriotic lesions after 24 months consisted of 69% new (and mostly subtle) implants, 10% remodeled lesions, and 21% unchanged implants. CONCLUSIONS: This study demonstrated that endometriosis in captive baboons undergoing repeated laparoscopies is a dynamic and moderately progressive disease with periods of development and regression and active remodeling between different types of lesions.     

A serial section study of visually normal posterior pelvic peritoneum from baboons (Papio cynocephalus, Papio anubis) with and without spontaneous minimal endometriosis

OBJECTIVES: To determine if microscopic endometriosis exists in visually normal pelvic peritoneum from baboons with and without endometriosis. DESIGN: Observational histologic study at Institute of Primate Research, Nairobi, Kenya. SUBJECTS: Seventeen baboons including 13 adult females (5 with histologically proven endometriosis, 8 with a normal pelvis) and 4 juveniles (1 female and 3 males). INTERVENTIONS: Diagnostic laparoscopy with identification of visually normal pelvic peritoneum before euthanasia, followed by laparotomy with excision of a large area (at least 4 x 6 cm or 24 cm2 per animal, 408 cm2 surface in all baboons) of this visually normal-appearing peritoneum. MAIN OUTCOME MEASURE: Presence of microscopic endometriosis (endometrial glands and stroma) in serial sections of visually normal pelvic peritoneum. RESULTS: Two adjacent glandular structures compatible with endometriosis were found in normal peritoneum obtained during menses from one female baboon without macroscopic disease. Microscopic endometriosis was not detected in the other female primates with or without macroscopic disease or in male animals. CONCLUSION: Microscopic endometriosis was found in only 1 of 14 female baboons (prevalence 7%; 95% confidence interval 0% to 33%) with visually normal pelvic peritoneum. These findings suggest that, with the paucity of human data available, more studies are needed before concluding that massive microscopic disease exists in visually normal-appearing peritoneum of women.     

The effect of dexamethasone administration at different stages of gestation on maternal plasma steroid concentrations in the baboon (Papio cynocephalus)

Dexamethasone administration at different stages of gestation in the baboon was studied for its effect on maternal steroid hormone concentrations. Dexamethasone (2 mg i.m. at 12 h intervals for three doses) was administered at early (days 37-39), mid (days 76-85) or late (days 112-123) gestation and morning blood samples were collected before, during and after dexamethasone suppression for 6 consecutive days. Dexamethasone treatment, at all stages of pregnancy, resulted in a significant decline in maternal serum cortisol concentrations, which rapidly return to normal concentrations after treatment. Progesterone concentrations were not affected by dexamethasone at any stage of gestation. Serum concentrations of oestradiol, testosterone and androstenedione were unchanged following dexamethasone administration in early pregnancy. A trend toward lower serum oestradiol was observed following dexamethasone administration in both mid and late gestation, but this was not significant. Both testosterone and androstenedione were significantly decreased following dexamethasone in both mid and late pregnancy and recovered to pretreatment concentrations within a few days after cessation of treatment. These results confirm other studies which demonstrate that adrenal precursors (maternal or fetal) are a major contributor to maternal serum concentrations of oestradiol. They also demonstrate that these adrenal precursors increase serum concentrations of testosterone and androstenedione in the pregnant baboon. Since these changes are only evident after that time (>40 days) when the fetal adrenal is steroidogenically competent, a role for fetal adrenal involvement in maternal serum androgen concentrations is suggested.     

The responses of female baboons (Papio cynocephalus ursinus) to anomalous social interactions: Evidence for causal reasoning?

Baboons' (Papio cynocephalus ursinus) understanding of cause–effect relations in the context of social interactions was examined through use of a playback experiment. Under natural conditions, dominant female baboons often grunt to more subordinate mothers when interacting with their infants. Mothers occasionally respond to these grunts by uttering submissive fear barks. Subjects were played causally inconsistent call sequences in which a lower ranking female apparently grunted to a higher ranking female, and the higher ranking female apparently responded with fear barks. As a control, subjects heard a sequence made causally consistent by the inclusion of grunts from a 3rd female that was dominant to both of the others. Subjects responded significantly more strongly to the causally inconsistent sequences, suggesting that they recognized the factors that cause 1 individual to give submissive vocalizations to another. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maternal effects on the development of social rank and immunity trade-offs in male laboratory mice (Mus musculus)

Social status in randomly constituted groups of male CFLP mice was predictable from early suckling behaviour and rate of weight gain in natal litters. High-ranking males were those that had suckled on more anterior teats and gained weight more quickly. Rank was not predicted by any measures of sibling interaction or hormone (testosterone, corticosterone) concentration. Aggressiveness in eventual high-rankers was associated negatively with the proportion of males in the litter at birth and the amount of maternal attention received. Aggressive social relationships within natal litters did not predict polarized rank relationships in randomized groups. Nevertheless, while still in their natal litters, and in the absence of aggressive rank relationships, eventual rank categories showed the same difference in modulation of testosterone concentration in relation to current immunocompetence (low-rankers modulating, high-rankers not), as has repeatedly been found in randomized groups by earlier studies. The role of maternal condition in determining rank-related life-history development in male mice is discussed.     

Effect of estrogen and progesterone on the expression of hepatic and extrahepatic sterol 27-hydroxylase in baboons (Papio sp)

Sterol 27-hydroxylase plays an important role in cholesterol metabolism in hepatic and extrahepatic tissues. To determine whether female sex steroid hormones influence its expression, we measured plasma and hepatic 27-hydroxycholesterol, hepatic mRNA levels, activity of sterol 27-hydroxylase, and adrenal mRNA levels of this enzyme in baboons (n = 6 per group) treated with placebo, estrogen, estrogen + progesterone, and progesterone. We also measured hepatic cholesterol concentration and hepatic acyl coenzyme A:cholesterol acyltransferase (ACAT) activity to determine their relationship with hepatic sterol 27-hydroxylase activity. Plasma 27-hydroxycholesterol concentration was increased by estrogen and estrogen + progesterone and was negatively correlated with plasma (P = .090) and LDL (P = .026) cholesterol concentrations. Similarly, hepatic sterol 27-hydroxylase activity was increased by estrogen and estrogen + progesterone and was negatively correlated with plasma (P = .056) and LDL (P = .052) cholesterol concentrations but was positively correlated with hepatic and plasma 27-hydroxycholesterol concentrations (P < .001). Hepatic ACAT activity was increased by progesterone (P < .004) and was positively correlated with plasma (P = .002) and LDL (P = .009) cholesterol concentrations but was negatively correlated with hepatic sterol 27-hydroxylase activity (P = .035). Hepatic and adrenal gland mRNA levels for sterol 27-hydroxylase were increased by estrogen alone or in combination with progesterone (P < .05). Hepatic sterol 27-hydroxylase activity was positively correlated with hepatic mRNA levels (P < .001), an observation suggesting that estrogen increases the activity of sterol 27-hydroxylase by increasing its synthesis. Hepatic cholesterol concentration was not influenced by the hormone treatment. These observations suggest that estrogen alone or in combination with progesterone increases the synthesis of sterol 27-hydroxylase in hepatic and extrahepatic tissues, and the increased activity of hepatic sterol 27-hydroxylase resulting from the increased synthesis is associated with a hypolipidemic effect on plasma LDL levels. Furthermore, progesterone alone increases the hepatic ACAT activity, but given in combination with estrogen progesterone does not have the same effect on hepatic ACAT activity. The effect of estrogen on hepatic ACAT activity may be mediated by sterol 27-hydroxylase and its effect on cholesterol metabolism (decreased cholesterol synthesis and increased output of cholesterol in the bile) in liver.     

Object manipulation and the use of tools by infant baboons (Papio cynocephalus anubis).

Infant baboons in a captive peer group used objects as containers, drinking utensils, and sponges in the context of play. The baboons later used paper, browse, and other materials as tools to extract sweet liquids from apparatus designed to accommodate sponging and probing behavior. Results demonstrate flexible combinatorial manipulation and spontaneous use of tools by infant baboons. These data are consistent with hypotheses that (1) an evolutionary history of omnivorous extractive foraging is associated with the use of tools and (2) free play in an object-enriched captive environment may facilitate combinatorial manipulation in nonhuman primates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mother-infant relationships in baboons (Papio hamadryas): Predictors of differences and discontinuities in developmental pathways.

This study uses hierarchical linear regression modeling to analyze sources of variation in the developmental pathways of mother-infant relationships and to search for behavioral discontinuities. The data come from 23 mother-infant dyads of baboons (Papio hamadryas), whose interactions were recorded longitudinally during the infants' 1st year of life. The infant's sex and the mother's age and reproductive experience accounted for part of the variation observed in the developmental pathways of 11 of 20 behavioral measures analyzed; however, some of them did so only in some periods but not in others. The authors proposed that this can reflect the occurrence of reorganizations or discontinuities in the mother-infant relationship that can be related to important life events such as the mother's resumption of sexual activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of melatonin, constant light, or blinding on reproductive system of gerbils (Meriones unguiculatus)

Male and female gerbils were implanted s.c. with a pellet containing 2 mg melatonin/23 mg beeswax every 2 weeks for a total of 3 implants. A significant depression of ovarian and uterine weight was noted in female gerbils receiving melatonin implants. In the melatonin-treated male gerbils, growth of the accessory organs was significantly inhibited although testis size was not depressed.     

The role of parasite-induced immunodepression, rank and social environment in the modulation of behaviour and hormone concentration in male laboratory mice (Mus musculus)

Peripheral immune responsiveness in male laboratory mice was reduced by infection with the trichostrongyloid nematode Heligmosomoides polygyrus. Responsiveness was also lower among high-ranking (aggressive) males regardless of infection status. Reduced responsiveness in both infected animals and high rankers was associated with elevated serum corticosterone concentration (a potential immunodepressant) and was compounded among high-ranking males by subsequent high aggressiveness. As in previous experiments, only low rankers modulated testosterone secretion in relation to current immunocompetence and corticosterone concentration. The lack of any downregulation of aggression in response to parasite-induced immunodepression contrasted with previous results using antithymocyte serum and may be due to the more localized nature of immunodepression during H. polygyrus infection. However, the additional increase in corticosterone concentration resulting from exposure to female odour and destabilized aggressive social relationships did result in downregulation of aggression among high rankers and of testosterone among mice generally, suggesting that modulation rules of thumb are at least partly dependent on the proximate cues associated with immunodepression.     

Integrating behavioral and social sciences research at the National Institutes of Health, U.S.A

Readers of Social Science & Medicine may find it interesting to know that in 1993 the United States Congress established the Office of Behavioral and Social Sciences Research (OBSSR) at the National Institutes of Health (NIH) in the belief that scientific research on behavioral and social factors in order to facilitate a growth in this important area of research. As is discussed in this paper, the philosophy of the OBSSR is that, although discoveries in the behavioral and social sciences are as critical for health as those from the biomedical sciences, knowledge from both areas must ultimately be integrated. Such integration will accelerate our understanding and treatment of physical and mental illnesses in both the developed and the developing world. This paper briefly presents the scientific evidence supporting this philosophy, outlines the mandated responsibilities of the OBSSR, and discusses some of its current and planned activities.     

Comparative studies on the in vitro decidualization process in the baboon (Papio anubis) and human

Blood supply is essential for the maintenance of epididymal function. Since there is no considerable neovascularization in the epididymis, this tissue could represent a suitable model to study the vascular endothelial growth factor (VEGF) effect for vascular permeability. We studied the expression and function of VEGF and its receptors fms-like tyrosine kinase (Flt-1) and fetal liver kinase (designated as kinase insert domain-containing receptor, KDR in the human) in the human epididymis. VEGF and VEGF receptors mRNA were detected in the human epididymal tissue. VEGF protein was localized in peritubular and in ciliated cells of efferent ducts as well as in peritubular and basal cells of the epididymal duct. Vascular endothelial cells did not express VEGF. Flt-1 protein was localized in ciliated cells of efferent ducts and in lymphatic vessels. Vascular endothelial cells were negative for Flt-1 but positive for KDR. In vitro VEGF165 treatment of epididymal tissue induced endothelial fenestrations and opening of interendothelial junctions. Additionally, we observed for the first time that VEGF could induce transendothelial gaps. We conclude that these gaps might be of importance not only for molecular transport but also for cell passage across the vessel wall, which may be significant for tumor metastasis. VEGF may act as a paracrine effector to influence the permeability of lymphatic vessels via Flt-1, and of blood vessels via KDR.     

The effect of ascorbic acid on the activity of lipoprotein lipase in the baboon (Papio ursinus)

The intravenous administration of heparin-released lipoprotein lipase (LPL) into the circulatory system of the baboon (Papio ursinus) is described. After a single heparin injection, a peak value of LPL activity appeared in the circulation with 5 minutes. At low doses of heparin (less than 100 units heparin/kg body mass), LPL disappeared from the circulation in an exponential fashion with a half-life of about 20 minutes. An increase in the heparin dose increased the amount of LPL released into the circulation. In baboons which were deficient in ascorbic acid, less LPL was released into the circulation after specific doses of heparin than in animals that were amply supplied with this vitamin (ascorbic acid 16 mg/kg body mass/day). The separation of plasma LOL, released by heparin, on Sephadex G-150, revealed several distinct molecular species of LPL in the eluant from the columns. In vitro studies indicated that ascorbic acid inhibited cardiac LPL strongly, whereas it had little effect on "post-heparin plasma" LPL. 2somolar concentrations of another reducing agent, mercapto-ethanol, slightly stimulated cardiac LPL in baboons.