Brainstem auditory evoked response development in preterm and term baboons (Papio hamadryas)

Brainstem auditory evoked responses were recorded longitudinally from 11 neonatal baboons (Papio hamadryas), 6 of which were preterm. Recordings were made in unsedated animals from day 161 to day 362 after conception (term = 182 days). The pattern of development of both waveform morphology and of wave latency was consistent with that seen in the human neonate, with a rapid maturation of the response during the perinatal period, and then a slower development to adult values. Brainstem conduction time was measured from the wave I to wave IV interval, and this demonstrated a similar pattern, with a rapid decrease in latency up to term, and then decreasing more slowly to reach adult values by 4 months of age in the baboon.     

Zoonotic intestinal parasites of hamadryas baboons Papio hamadryas in the western and northern regions of Saudi Arabia

Six hundred and thirty-three faecal samples were randomly collected and examined for ova and cysts of intestinal parasites from five groups of hamadryas baboons of different population densities, with different human contact and in different ecological conditions (Al-Baha, Turabah and Al-Taif in south-western and Al-Rihat and Al-Akhal in north-western Saudi Arabia). Nine parasites were recorded (Giardia lamblia, Entamoeba histolytica, Escherichia coli, Balantidium coli, Enterobius sp., Trichuris sp., Hookworm, Hymenolepis nana and Schistosoma mansoni) in 274 samples (43.28%). The prevalence of parasites was high (36.0-58.5%) in areas of mild, cool climatic conditions, where baboons were at high density and had maximum human contact. However, in an area (Al-Akhal) of hot, dry climatic conditions, low baboon density and minimum human contact, the parasites' prevalence was very low (9.5%). The concentration of parasites (ova or cysts per g of faeces) was medium. Post-mortem examination of 24, 20, 19 and 13 baboons from Al-Baha, Al-Taif, Turabah and Al-Rihat revealed most of the parasites recorded in random faecal samples at prevalence rates of 37.5, 30.0, 36.0 and 23.0% respectively. The overall prevalence rate was 32.9%. Most of the parasites recorded in baboons were also recorded in humans in the areas of study.     

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)     

Diet, plasma lipoproteins and experimental atherosclerosis in baboons (Papio sp.)

Diet-induced hyperlipidaemia in baboons is similar to that in humans. As in humans, the ratio between low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol is a major determinant of atherosclerosis. Baboons, like humans and other non-human primates, vary in their lipaemic responses to dietary lipids. By selective breeding based on variability in plasma and lipoprotein cholesterol response to diet, lines of baboons with high and low responses of various lipoproteins have been developed. Genetic analyses suggest that lipoprotein patterns in response to dietary cholesterol and fat are heritable. Metabolic and molecular studies of high and low LDL and HDL cholesterol responses to dietary lipids have suggested that different mechanisms regulate plasma LDL cholesterol on the chow and on the high cholesterol-high fat (HCHF) diet. On the chow diet, plasma LDL cholesterol levels are positively associated with cholesterol absorption and negatively associated with hepatic LDL receptor levels and, thus, cholesterol absorption and LDL receptors seem to regulate plasma LDL cholesterol levels. However, when the animals consume a human-like fat- and cholesterol-enriched diet, plasma LDL cholesterol levels are not associated with either cholesterol absorption or hepatic LDL receptor mRNA levels, but are negatively associated with plasma 27-hydroxycholesterol concentrations, hepatic sterol 27-hydroxylase activity, and mRNA levels. Hepatic sterol 27-hydroxylase activity and mRNA levels are induced by dietary cholesterol and fat in low responding baboons more than in high responding baboons. Thus, the ability to induce sterol 27-hydroxylase determines the LDL cholesterol response in baboons. High HDL response baboons often have high levels of HDL1 in their plasma. Our studies suggest that the N-terminal fragment of apo C-I with 38 amino acids and a molecular weight of approximately 4 kDa acts as a cholesteryl ester transfer inhibitor peptide in high HDL1 baboons. The inhibitor peptide associates with apo A-1 in HDL to produce a modified apo A-1 protein with a molecular weight of approximately 31 kDa. The inhibitor peptide is a gene product and the presence of this peptide produces an antiatherogenic high HDL1 phenotype.     

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.     

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.     

Inferential reasoning and modality dependent discrimination learning in olive baboons (Papio hamadryas anubis).

Apes use inferential reasoning by exclusion to locate food both in the visual and auditory domain. To test whether olive baboons (Papio hamadryas anubis) show similar abilities as the apes object choice experiments with differing information about food located in 1 of 2 cups were conducted in the visual and auditory modality. Although all baboons (N = 7) were able to locate the reward when they had previously seen it, they failed to make use of auditory cues or arbitrary acoustic signals. When only partial information was given (i.e., only 1 cup was opened) 4 of the baboons were apparently able to infer the location of the reward by reasoning, whereas the other 3 may have adopted an alternative strategy (“avoid the empty cup”). In addition, 3 of the baboons were able to use arbitrary visual markers to locate the food reward. The results suggest that inferential reasoning is not restricted to apes but is shared with Old World monkeys. Furthermore, they also highlight some important differences in the processing of auditory versus visual information in operant conditioning settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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.     

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.     

Changes of extracellular matrix in a baboon (Papio hamadryas) model of insulin dependent diabetes: studies using electron microscopy and X-ray diffraction techniques

Extracellular matrix plays an important role in many physiological functions and its abnormalities are thought to play a key role in the pathogenesis of diabetic complications. In this paper we used the techniques of electron microscopy, immunostaining and X-ray diffraction to document some of the early events in the changes of extracellular matrix in a model of insulin dependent diabetes in baboons. Our results show that thickening of basement membrane and enlargement of mesangium are demonstrable in the glomeruli of prepubertal diabetic baboons within 2 years from the onset of diabetes. Concomitant with this was the accumulation of type IV collagen and laminin in the mesangium. By contrast, even the very sensitive technique of X-ray diffraction failed to demonstrate changes in the equatorial direction of collagen molecules of the skin and tendon. We conclude that changes of glomerular extracellular matrix are demonstrable early in insulin dependent diabetes even in prepubertal baboons. These can be used as endpoints in evaluating the efficacy of pharmacological agents such as aminoguanidine in preventing diabetic complications.     

Linkage mapping in Papio baboons: conservation of a syntenic group of six markers on human chromosome 1

We have established multipoint genetic linkage among six loci in baboons (Papio hamadryas). Published PCR primers designed to amplify five human microsatellite loci were used to amplify homologous loci in 229 pedigreed baboons. Southern blotting was used to type two RFLPs in a functional gene (anti-thrombin III) in a subset of those animals. All six loci are known to map to human chromosome 1q, a region of the genome predicted by karyotype studies to be conserved in baboons. Pairwise recombination frequencies and lod scores indicate that the six loci are also linked in baboons. Recombination distances among the loci are similar to those reported for humans. Like humans, the baboons exhibit higher rates of recombination in females than in males. This study demonstrates that (1) microsatellite loci first described and characterized in the human genome can be effectively used for genetic linkage mapping in non-human primates, (2) a group of genetic loci known to be linked on human chromosome 1q are also linked in the baboon genome, and (3) sex differences in recombination frequencies among loci on human chromosome 1q are also observed in the genome of this Old World monkey. This constitutes the first reported multipoint linkage map in any nonhuman primate.     

Ageing and social rank effects on the reproductive system of free-ranging yellow baboons (Papio cynocephalus) at Mikumi National Park, Tanzania

The Wnts can be classified into two classes based on their ability to transform cells. The Wnt5a class can antagonize the effects of transforming Wnts partly through effects on cell migration. To understand the mechanisms of regulation of Wnt5a, we investigated its expression in human normal and breast cancer cell lines. Elevation of Wnt5a in HB2, a normal breast epithelial cell line, was linearly correlated with cell density, but this did not occur in cancer cell lines. We examined intracellular events responsible for the regulation of Wnt5a by cell to cell contacts, using various metabolic agents known to affect signal transduction pathways. Agents that selectively blocked protein kinase C (calphostin C) or protein tyrosine kinases (genistein) reduced the level of Wnt5a expression markedly. Protein kinase C activation by phorbol 12-myristate 13-acetate up-regulated Wnt5a partly through prolongation of Wnt5a mRNA half-life. Cytoskeleton reorganization following cytochalasin D treatment caused an induction of Wnt5a, which was associated with changes in cell morphology. Calphostin C did not block these effects, showing that protein kinase C is acting upstream of cytoskeletal modulation. However, the cancer cell lines treated with cytochalasin D showed no changes in cell morphology or Wnt5a induction, suggesting disruption of this regulatory pathway in cancer.     

Ontogenetic changes in the comprehension and production of vervet monkey (Cercopithecus aethiops) vocalizations.

Factors underlying the development of the East African vervet monkeys' intergroup wrr vocalization were examined. Infants produced the intergroup wrr in appropriate social contexts between 10–28 months, but the acoustic morphology of this call differed significantly from those produced by adults. Auditory and social experience affected the age at which infants produced adult-like exemplars of the call, as well as the age at which they comprehended the call's meaning. Although the developmental time course for the production of intergroup wrrs is gradual, young infants (birth to 3 months) produce a wrr-like call in the context of distress which appears to be articulated in a more adult-like manner than older infants. It is hypothesized that maturational changes in vocal morphology, increasing motoric control and experience are important factors in the ontogeny of nonhuman primate vocal communication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogenetic changes in two forms of the Muller-Lyer illusion in normal and retarded subjects.

Forms A (arrowheads pointing out) and B (arrowheads pointing in) of the Muller-Lyer illusion were administered to normal and retarded Ss to study possible changes in illusion strength in either or both forms. It was found that only Form A changed in strength when (a) age was varied from 8-18 yrs in normal children and (b) when the illusion was presented repeatedly over 8 trials for normal and retarded children. These findings conflict with perceptual theories which assume that both forms of the illusion change with these manipulations. A control condition was also presented and its utility is discussed. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogenetic changes in the modulation of taste aversion learning by home environmental cues in rats.

Conducted 3 experiments using 611 Sprague-Dawley rats to define and analyze an age-related phenomenon of conditioned taste aversion. When consumption of sucrose solution was followed by LiCl-induced illness in Ss' home, acquisition of the aversion to sucrose solution was retarded in preweanling (18-day-old) Ss. This effect was not found in adults or in 21-day-old Ss. Place of testing had no effect in the younger 2 age-groups, but in adults manifestation of the acquired aversion was retarded when they were tested in the home. There was no interaction between place of conditioning and testing for any age. The locus of the environmental influence on conditioning in preweanling Ss was found to be the place of tasting rather than place of illness, retention interval, or testing. Also, the effect was found to be invariant under minor variations in familiarization of Ss with the nonhome environment. The principle emerging from these data and others is that the home environment can have a significant influence on learning and conditioning in the immature rat. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transformation-induced alterations in the regulation of tyrosine aminotransferase expression in fetal rat hepatocytes: changes in hormone inducibility and the DNase-hypersensitive site

Regulation of expression of tyrosine aminotransferase (TAT) is examined in two cell lines (FRL) obtained by chemical transformation of cultured fetal hepatocytes derived from 19-day rat fetuses (FL19). Steroid induction of TAT is unaffected by transformation, while the response to cyclic AMP is attenuated. Consequently a synergistic response elicited by the simultaneous exposure of normal fetal hepatocytes to the inducers is almost abolished in FRL cells. FL19 and FRL are similar with respect to the negative effect of insulin on steroid induction, which is a response restricted to prenatal liver. Detailed examination of chromatin reveals that the attenuated effect of cyclic AMP is consistent with the lack of the DNase I-hypersensitive site located at about the cyclic AMP response element of the TAT promoter. From the studies, we conclude that transformation results in the modification of some aspects of TAT regulation, while others have been retained, and reflects the fetal pattern which is observed in normal embryonic hepatocytes.     

The involvement of innervation in the regulation of fetal adrenal steroidogenesis

Over the last decade, great interest has been generated in evaluation of the extent of neural control of the adrenal cortex and in adrenal cortical/medullary paracrine interactions. The purpose of this review is to summarize current knowledge of fetal adrenal cortical innervation and to present an overview of those studies of fetal adrenal function indicating that adrenal innervation plays a functional role in the control of glucocorticoid secretion under basal conditions and in response to a variety of homeostatic challenges. It will be helpful in understanding both the innervation of the adrenal cortex and the role of adrenal innervation in steroidogenesis during fetal development to briefly review experimental studies that have shed light on adrenal steroidogenesis during postnatal life. This is helpful for two reasons: 1) the vast majority of studies of adrenal innervation and its effect on steroidogenesis have utilized postnatal animals and 2) since the fetus is preparing for postnatal life, evaluating the level of function achieved postnatally provides crucial insights into the developmental stages of adrenal innervation and its role in steroidogenesis in preparing the fetus for an independent postnatal existence.     

Alternanthera philoxeroides (Mavt.) Griseb protection against fetal epidemic hemorrhagic fever virus infection in suckling mice

It has been confirmed that Alternanthera philoxeroides (APG) can markedly protect suckling mice from being infected by epidemic hemorrhagic fever (EHF) virus. After the infected mice were treated with the effective components their survival rate increased, pathological lesion and virus antigen in the tissues mitigated as compared with the controls. Therapeutical dose of APG caused only slight deformation of the hepatic cells.