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PubMed1997

Distribution of endocrine cells displaying immunoreactivity for one or more peptides in the pancreas of the adult vervet monkey (Cercopithecus aethiops).

BACKGROUND: Our previous studies on the Chacma baboon revealed that the most striking difference between islets of the ventral and dorsal regions of the pancreas was their content of A and pancreatic polypeptide (PP) cells with A cells predominating in the tail and PP cells in the uncinate and head. Cells displaying dual immunoreactivity for both glucagon and PP were also observed. The objective of this study was to establish baseline parameters of the adult Vervet monkey (Cercopithecus aethiops) pancreas so that it could be used as a primate model to investigate possible therapies for diabetes. METHODS: Vervet-monkey pancreas was divided into uncinate, head, and tail regions, and the tissue processed for immunolabelling for pancreatic peptides using avidin-biotin-peroxidase as marker. Dot-blotting and absorption controls for antibody specificity were included because of the shared amino acid sequences in pancreatic polypeptide (PP), neuropeptide Y (NPY), and peptide YY (PYY). Endocrine cell distributions and the percentages of each cell type per region were calculated for each monkey. RESULTS: A significant difference in the percentages of PP cells (P = 0.02) was observed between uncinate and tail regions, the distribution of NPY cells was similar to that of the PP cells, and all other distributions were similar to those reported in the literature for most animals studied. Cells displaying dual immunoreactivity for glucagon and PP or NPY, PYY and NPY, or PP, PP and somatostatin and glucagon and insulin were identified and mapped throughout the pancreas. Most co-localizations occurred in the uncinate region. Co-localization of glucagon and insulin has not, to our knowledge, been reported previously in the adult pancreas. CONCLUSIONS: Pancreatic endocrine cell distribution in the adult Vervet monkey was found to be very similar to most other animals studied. The occurrence of cells displaying dual immunoreactivity for a number of different combinations of pancreatic peptides suggests an interesting plasticity of endocrine cells even in the adult animal.

Animals↗

PubMed1999

Differential habitat utilization by patas monkeys (Erythrocebus patas) and tantalus monkeys (Cercopithecus aethiops tantalus) living sympatrically in northern Cameroon.

In order to obtain reliable evidence for differences in habitat preferences between two closely related savanna-dwelling primate species, namely, patas monkeys (Erythrocebus patas) and tantalus monkeys (Cercopithecus aethiops tantalus), I collected data on vegetation and patterns of range use concurrently at a single study site, Kala Maloue, Cameroon, in a similar manner for a group of each species. Kala Maloue consisted of 64% grassland mostly dominated by Gramineae spp. and the rest was woodland. Tantalus monkeys showed preference for woodland, especially gallery forest, much more than did the patas irrespective of the season. Moreover, patas preferentially established their home range in grassland in the wet season. Interspecific and seasonal differences in habitat preferences could be interpreted on the basis of interspecific and seasonal differences in preferences for main food. In dry season, tantalus utilized water-containing areas at a frequency closely in proportion to the availability of such areas while the patas utilized water-containing areas more frequently than expected. This is because tantalus established a smaller home range along the river where water was never completely depleted throughout the dry season. Both the patas and the tantalus preferred woodland to grassland as sleeping sites possibly owing to predation avoidance. Both the daily travel distance per group weight and the home range size per group weight were greater for patas than for tantalus partly because of higher preference for grassland with low habitat quality in the case of patas. It is suggested, however, that high locomotive ability enabled patas to effectively utilize small and widely dispersed items of food such as grasshoppers and to explore areas with high availability of food and water and with preferable sleeping sites.

Animals↗

PubMed2002

Comparison of responses to alarm calls by patas (Erythrocebus patas) and vervet (Cercopithecus aethiops) monkeys in relation to habitat structure.

We studied responses to alarm calls of sympatric patas (Erythrocebus patas) and vervet (Cercopithecus aethiops) monkeys in relation to habitat structure, with the intention of understanding the relationship between the environment and predator avoidance. Patas and vervet monkeys are phylogenetically closely related and overlap in body size. However, while patas monkeys are restricted to nonriverine habitats at our study site, vervets use both nonriverine and riverine habitats, allowing us to "vary" habitat structure while controlling for effects of group size, composition, and phylogeny. Patas monkeys in the nonriverine habitat responded to mammalian predator alarm calls with a greater variety of responses than did vervets in the riverine habitat, but not when compared with vervets in the nonriverine habitat. Ecological measurements confirm subjective assessments that trees in the riverine habitat are significantly taller and occur at lower densities than trees in the nonriverine habitat. Despite the lower density of trees in the riverine habitat, locomotor behavior of focal animals indicates that canopy cover is significantly greater in the riverine than the nonriverine habitat. Differences in responses to alarm calls by the same groups of vervets in different habitat types, and convergence of vervets with patas in the same habitat type, suggest that habitat type can be a significant source of variation in antipredator behavior of primates.

Animals↗

PubMed1978

Developmental staging and thalidomide teratogenicity in the green monkey (Cercopithecus aethiops).

The developmental stages of 11 Cercopithecus aethiops embryos, 24 to 45 days post-mating, are described. The onset of organogenesis in this species is approximately five to seven days later than that reported for macaques and baboons. This temporal difference in the embryonic period is an important factor in the analysis of the subsequent teratogenic study. Oral administration of thalidomide in single or multiple (3-day) treatment periods to pregnant green monkeys between days 28 and 33 resulted in defects of the limbs which resemble those observed in macaques and baboons. However, the sensitive period occurs approximately four days later than that reported for another nonhuman primates. These results indicate that the sensitive period of the limbs to thalidomide coincides with their earliest development.

Abnormalities, Drug-Induced↗

PubMed1991

Retention of leptospiral agglutinins and long-term response to administration of monoclonal antibodies in vervet monkeys (Cercopithecus aethiops) on Barbados.

In a study of 21 wild-caught Barbadian vervet monkeys (Cercopithecus aethiops sabaeus), naturally-acquired leptospiral agglutinins were found to persist for over five years. Groups of seropositive as well as seronegative vervets were given a placebo, or full-strength monoclonal antibodies MCA F12C3 (Icterohaemorrhagiae copenhageni), or diluted F12C3 MCAs. They were challenged 24 hours later with a suspension of highly virulent leptospires (copenhageni) administered intraperitoneally. Immunoprotection was evident in animals receiving full strength MCAs as measured by their failure to develop any substantial antibody response and by their lower geometric mean titres over a period of 142 weeks (maximum GMT of 113 compared with a maximum of 1280 in the placebo group). Diluted MCAs had little or no protective value. The serological response of the monkeys which were seropositive at capture to challenge with virulent copenhageni antigen was strongly anamnestic both in those given MCAs and those given placebo. None of the naturally or experimentally infected vervets showed clinical signs of leptospiral illness.

Agglutinins↗

PubMed1986

Immunocytochemical localization of S-100 protein in stellate cells (folliculo-stellate cells) of the adenohypophysis in the monkeys Macaca irus and Cercopithecus aethiops.

With the use of an antibody against bovine S-100 protein, it was possible to reveal a characteristic cell type in the pars distalis and the pars tuberalis of the monkey Macaca irus. In the adenohypophysis of Cercopithecus aethiops, labeled cells were present in the pars distalis, pars tuberalis, and pars intermedia. These cells, so-called folliculo-stellate cells, were found in all pituitaries studied. Surprisingly, an antibody against human S-100 protein did not label the stellate cells of the adenohypophysis. However, in Macaca irus, this antibody gave a strong positive reaction with various other cell types (interstitial cells of the pineal gland, Müller cells of the retina, autonomic ganglionic cells, glial cells of the central nervous system, Schwann cells, Bergmann glia of the cerebellum, fat cells, reticular cells of lymphoid organs). By use of double immunoenzymatic labeling, it was evident that stellate cells are spatially related either to somatotropes, prolactin cells, "corticotropes", or to glycoprotein-containing cells. Thus, a specific relationship to a particular endocrine-cell type could not be observed.

Animals↗

PubMed1981

Immunohistochemical localization of FSH and LH in the pars distalis of vervet (Cercopithecus aethiops) and baboon (Papio hamadryas) pituitaries.

Antisera against oLH, beta oLH and beta hFSH were used to localize gonadotropic cells in the pars distalis of Cercopithecus aethiops and Papio hamadryas. Three separate cell types were observed for FSH and LH: 85% of immunohistochemically identified gonadotropic cells reacted to all the various antisera; 10% reacted with the anti-beta oLH antibody only; and 5% with the anti-beta hFSH antibody only. Comparisons between adjacent serial sections treated with various antisera, other than anti-gonadotropic hormones, demonstrated that the "gonadotropic cells" of these monkeys did not respond to these antisera.

Animals↗

PubMed1980

Scanning electron microscopy of frozen-cracked, dry-cracked, and enzyme-digested retinal tissue of a monkey (Cercopithecus aethiops) and of man.

Cracking and enzyme-digestion methods were applied to retinal tissue from a monkey (cercopithecus aethiops) and from man. By scanning electron microscopy (SEM) of the various layers of the retina, as well as of single cells, cell connections and cell interiors were demonstrated in a three-dimensional form. The methods were particularly successful in demonstrating the fibre baskets of Müller cells and the tongue-like processes of the inner photoreceptor segments surrounding the outer segment. Cristae-like protrusions of the inner segments lying in rows along the axis of the segment, possibly disconnected interphotoreceptor contacts, were clearly seen.

Animals↗

PubMed2002

The finding of an inverse relationship between social dominance and feeding priority among pairs of unfamiliar adult male vervet monkeys (Cercopithecus aethiops sabaeus).

Dominance is often presumed to confer priority of access to resources. This study evaluated the relationship between two assessments of dominance: (1) social dominance, based on agonistic interactions and (2) feeding priority among pairs of unfamiliar adult vervet monkeys (Cercopithecus aethiops sabaeus) differing in scrotal colour, but matched for height, weight and testicular volume, during paired introduction experiments. Results of this investigation showed that neither size differences nor scrotal colour were predictive of feeding priority, and social dominance was inversely related to feeding priority. This finding demonstrates that different assessments of dominance can yield different outcomes even within the same primate taxon. I propose that male dominance rank may best predict access to resources when there is direct contest competition over a resource, which is not immediately exhaustible, whereas highly impulsive low ranking males may gain a competitive edge in scramble competitions for ephemeral and small resources.

Aggression↗

PubMed1976

Characterization of a spontaneous undifferentiated carcinoma from an African green monkey (Cercopithecus aethiops).

An adult male African green monkey (Cercopithecus aethiops) with an undifferentiated carcinoma, probably originating from the nasal mucosa, was received from the Akron, Ohio zoo. Cultivation of this tumor in vitro resulted in a mixture of fibroblastic and epithelial cells which was subsequently separated using differential trypsinization. The neoplastic nature of the cultured epithelial cells was verified by their ability to transplant into athymic nude, or antithymocyte serum-treated mice, where poorly differentiated carcinomas were produced, and cultures of the tumors that arose in nude mice were morphologically similar to pretransplantation cultures. Early cultures showed a normal male karyotype characteristic of the species; however, in long-term cultures, a clearly defined, small submetacentric Y chromosome was not observed. Electron microscopic examination of tumor tissue and cultured tumor cells revealed desmosomes and the presence of cytoplasmic (keratin-type) fibrils, which tended to be organized around the nucleus. In addition to the keratin-type fibrils, the cultured tumor cells also contained a large amount of cytoplasmic inclusion material that may represent keratohyalin granules. There was no evidence of a viral association with tumor material or cultured cells. The cultures were susceptible to infection by vesicular stomatitis virus, Herpesvirus hominis type 1, and H. saimiri, but were resistant to the Epstein-Barr virus.

Animals↗

PubMed2001

Toxicokinetics of ochratoxin A in vervet monkeys (Cercopithecus aethiops).

The toxicokinetics of ochratoxin A were investigated in vervet monkeys (Cercopithecus aethiops). Three female monkeys were treated intravenously with ochratoxin A at doses, respectively, of 0.8, 1.5 and 2 mg/ kg body weight (BW). Blood and urine samples were collected over a period of 21 days. Plasma and urine extracts were analysed by high-performance liquid chromatography (HPLC) with either fluorescence or negative ion electrospray ionization mass spectrometric detection. The clearance of ochratoxin A from plasma followed a two-compartment model. The elimination half-life of ochratoxin A in the monkeys was determined to be 19-21 days and the average total body clearance was 0.22 +/- 0.07 ml/h per kg and the average apparent distribution volume of the central compartment was 59 +/- 9 ml/kg and the peripheral compartment was 59 +/- 20 ml/kg. No evidence was found for any metabolic conversion of ochratoxin A.

Animals↗

PubMed2005

Probing the limits of tool competence: experiments with two non-tool-using species (Cercopithecus aethiops and Saguinus oedipus).

Non-human animals vary in their ability to make and use tools. The goal of the present study was to further explore what, if anything, differs between tool-users and non-tool-users, and whether these differences lie in the conceptual or motor domain. We tested two species that typically do not use tools-cotton top tamarins (Saguinus oedipus) and vervet monkeys (Cercopithecus aethiops)-on problems that mirrored those designed for prolific tool users such as chimpanzees. We trained subjects on a task in which they could choose one of two canes to obtain an out-of-reach food reward. After training, subjects received several variations on the original task, each designed to examine a specific conceptual aspect of the pulling problem previously studied in other tool-using species. Both species recognized that effective pulling tools must be made of rigid materials. Subsequent conditions revealed significant species differences, with vervets outperforming tamarins across many conditions. Vervets, but not tamarins, had some recognition of the relationship between a tool's orientation and the position of the food reward, the relationship between a tool's trajectory and the substance that it moves on, and that tools must be connected in order to work properly. These results provide further evidence that tool-use may derive from domain-general, rather than domain-specific cognitive capacities that evolved for tool use per se.

Animals↗

PubMed2002

Difference in food selection between patas monkeys (Erythrocebus patas) and tantalus monkeys (Cercopithecus aethiops tantalus) in Kala Maloue National Park, Cameroon, in relation to nutrient content.

Phytochemical or nutrient analyses of primate diets have revealed clues to their food selection in a single species. On the other hand, few interspecific comparisons of phytochemical or nutrient composition of primate diets have been made, although diets are considered to differ in phytochemical or nutrient content from primate species to species, since different species have different body weights and different morphological and physiological characteristics. I compared the nutrient content of diet between patas monkeys ( Erythrocebus patas) and tantalus monkeys ( Cercopithecus aethiops tantalus) living sympatrically in Cameroon. Patas subsisted on a smaller number of food items, most of which were also tantalus food items. Then, I compared the protein-fiber ratio and the available energy content of the food items eaten by patas (patas foods) with those items eaten only by tantalus (tantalus foods). Both variables were higher in patas than tantalus foods, although there was no significant difference in available energy of plant foods. Next, when I performed discriminant analysis for patas foods and tantalus foods, employing the above two variables, a discriminant function with positive coefficients for both variables was obtained. The mean discriminant-function score of patas foods was higher than that of tantalus foods. Despite being somewhat larger in weight, patas selectively fed on a smaller number of foods of higher quality than did tantalus. I discuss why the results are inconsistent with a well known body weight-diet relationship (Jarman-Bell principle). Energy-efficient locomotion enables patas to exploit not only small dispersed food items of high quality but also areas where high-quality foods are distributed in clumps.

Animal Nutritional Physiological Phenomena↗

PubMed1987

Duct-associated lymphoid tissue (DALT) of minor salivary glands in the monkey, Cercopithecus aethiops.

This study reports on the characteristic topographical distribution of DALT within the labial and buccal mucosae of Cercopithecus aethiops. A total of 140 labial and 24 buccal mucosal tissue blocks, originating from 11 animals, were examined light microscopically. All animals revealed DALT in varying numbers of Epon blocks. In C. aethiops, DALT is a comparatively rare phenomenon and appears to develop almost exclusively around MSG duct orifices and along the course of main ducts traversing the subepithelial lamina propria. The location of DALT in C. aethiops, therefore, seems to be anatomically more restricted than in other species (Macaca fascicularis and Macaca mulatta) in which DALT has been studied more extensively.

Animals↗

PubMed1985

Steroid hormone influences on the mating behavior of vervet monkeys (Cercopithecus aethiops).

Eight ovariectomized female vervet monkeys (Cercopithecus aethiops) were tested in heterosexual and isosexual pairs, under estradiol and testosterone treatments. Pairs were tested under two different experimental situations in which the male was either restrained or left free. There were only small behavioral changes across the treatments, involving mainly male responses. Erection time, frequency of intromission, ejaculation, and olfactory investigation increased during estradiol treatment whereas during administration of testosterone erection time, the number of approaches, contacts, and olfactory investigations decreased. Female behaviors were relatively independent of hormone treatment showing only the disappearance of negative responses with estradiol and an increase of yawns with testosterone. Female behaviors were performed at a higher level with male partners than with other females, and the frequencies of spontaneous presents varied with the sex of partner. It is suggested that in vervet monkeys both estradiol and testosterone affect female attractivity, estradiol further influences receptivity, whereas proceptivity appears to be less directly involved in sexual interactions and more related to social context.

Animals↗

PubMed1983

Long-term infection of Schistosoma mansoni in a vervet monkey (Cercopithecus aethiops).

Schistosoma mansoni infection in Cercopithecus species monkeys has been previously monitored for up to five years. This is an account of observations made during an autopsy on a male vervet monkey which had harboured the parasite for 15 years. Viable eggs had been recovered from the faeces throughout the infection, being hatched to observe the emergence of miracidia. Apart from a nodular appearance of the liver capsule, which was noted before the perfusion, and localized haemorrhaging in the large bowel there was comparatively little pathology attributable to the parasite. 86 worms were recovered from the mesenteries by perfusion. The distribution of worm eggs in the tissues was mainly in these two organs, although with the remarkably low incidence of granuloma it is likely that the schistosome infection would have been overlooked in a routine autopsy. It is stressed that these observations have been made on an individual animal, but it is felt that there is real significance with respect to the aetiology of natural transmission.

Animals↗

PubMed1993

Autoradiographic localization of putative melatonin receptors in the brains of two Old World primates: Cercopithecus aethiops and Papio ursinus.

The distribution of putative melatonin receptors in the brains of two Old World primates of the superfamily Catarrhina, Cercopithecus aethiops and Papio ursinus, was characterized using 2-[125I]iodomelatonin autoradiography. The specific binding demonstrated a discrete distribution pattern. The median eminence was intensely labelled, and examination at the light microscopic level demonstrated that the binding was confined to the small layer of cells comprising the pars tuberalis of the pituitary gland. The collar of pars distalis, present in the baboon (Papio ursinus), was diffusely labelled. No binding was detected in the pars distalis proper or the neural lobe of the pituitary gland. The binding in the suprachiasmatic nuclei was weaker, but well discernible. Diffuse faint specific binding was found in the frontal cortex and the dentate gyrus of the hippocampus. Two non-neural sites expressed strong, well-delineated binding: the walls of some brain blood vessels (the vertebral and spinal arteries, the inferior cerebellar and acoustic arteries, the basilar, pericallosal, internal carotid arteries, the arteries forming the circle of Willis) and the choroid plexuses. Binding in the arteries of the circle of Willis, the pars tuberalis and the suprachiasmatic nuclei was readily displaceable. Addition of 1 microM unlabelled 2-iodomelatonin following 45 min of preincubation with the radioactive ligand completely abrogated the binding. Co-incubation with guanosine 5'-O-(3-thiotriphosphate) led to a significant decrease in the apparent binding density in the pars tuberalis and abolished binding in the suprachiasmatic nuclei, but was without effect on the binding in the walls of the adjacent arteries, forming the circle of Willis, in the cortex and in the hippocampus. This qualitative distribution pattern demonstrates that in the two primate species studied, melatonin high-affinity, G-protein-linked binding sites are present in the pars tuberalis and the hypothalamic suprachiasmatic nuclei, and that melatonin may be acting as a synchronizer of the endogenous pacemakers' circadian activity, apart from its possible reproductive effects at the level of pars tuberalis, where the highest receptor density was observed. The strongly labelled arterial walls, and the flimsy labelled cortex and hippocampus, expressed different characteristics: though the binding was readily reversible, it was apparently not regulated by a guanine nucleotide-binding protein.

Animals↗

PubMed2004

Zoonotic intestinal parasites in Papio anubis (baboon) and Cercopithecus aethiops (vervet) from four localities in Ethiopia.

A total of 59 faecal samples from ranging Papio anubis (baboons) and another 41 from Cercopithecus aethiops (vervet) from the Rift Valley areas of Ethiopia were microscopically examined to determine the prevalence and species of major gastro-intestinal parasites of zoonotic importance. Faecal smears were prepared from fresh faecal samples, stained using modified Ziehl-Neelsen method and microscopically examined. About 3 gm of the dropping was also preserved separately in clean and properly labelled containers containing 10% formalin. The specimens were microscopically examined after formalin-ether concentration for ova, larvae, cysts and oocyst of intestinal parasites. The results of microscopic examination of faecal samples of baboons demonstrated the presence of Trichuris sp. (27.1%), Strongyloides sp. (37.3%), Trichostrongylus sp. (8.5%), Oesophagostomum sp. (10.2%), Schistosoma mansoni (20.3%), Entamoeba coli (83.1%), Entamoeba histolytica/dispar (16.9%), Blastocystis hominis (3.3%), Cyclospora sp. (13.3%) and Cryptosporidium sp. (11.9%). Likewise, the results of microscopic examination of faecal samples of vervets demonstrated the presence of Trichuris sp. (36.6%), Oesophagostomum sp. (4.9%), E. coli (61.0%), E. histolytica/dispar (24.4%), B. hominis (34.2%), Cyclospora sp. (22.0%) and Cryptosporidium sp. (29.3%). The presence of parasitic protozoa and helminths in baboons and vervets in the study areas is a high risk to human welfare because these non-human primates use the same water sources as humans and range freely in human habitats. An implication of such parasitic infection for the control programme is discussed.

Animals↗