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PubMedDate not supplied

Changes in social dynamics associated to the menstrual cycle in the vervet monkey (Cercopithecus aethiops).

Behavioral changes associated to the menstrual cycle in a social group of vervet monkeys (Cercopithecus aethiops) were studied. Three adult females were used as experimental subjects and in these, vaginal smears were taken every other day in order to detect their menstrual cycles. Only the dominant and the mid-ranking female showed regular cycles while the low-ranking female showed amenorrhea. The menstrual cycles were divided into five periods (menstrual, premenstrual, luteal, ovulatory and follicular) which were related to the behavioral data. Social behavior recordings were taken during one hour daily for five consecutive months; the data were adjusted twice in order to follow the cycles of the females with regular menstruations. By plotting in a matrix the relative frequencies of joins and displacements, the social position of each animal as well as the group's social organization and dynamics were evaluated. A clear tendency towards social rejection (emitting less joins and increasing the amount of displacements) was detected during the premenstrual periods of the dominant female which abruptly changed towards affiliation during menstruation. This observation was detected in all group members no matter their age-sex class or social position during the five months of observation. When the data were analyzed following the mid-ranking female's cycle, no consistent changes were apparent. The importance of social stimuli in the modulation and expression of hormone-related behavior is stressed, as well as the need of using social settings in the experimental analyses of premenstrual mood and behavior disorders.

Animals↗
PubMed1988

Retinal epithelial fine structure in the vervet monkey (Cercopithecus aethiops).

The morphology of the retinal pigment epithelium (RPE) and closely associated Bruch's membrane (complexus basalis) and choriocapillaris have been investigated by electron microscopy in the vervet monkey (Cercopithecus aethiops). The RPE is composed of a single layer of cuboidal cells joined laterally by apically-located junctional complexes. Basally (sclerally) these cells display numerous infoldings while apically (vitreally) abundant processes enclose and interdigitate with rod outer segments. Internally the large vesicular nucleus is centrally located and smooth endoplasmic reticulum, mitochondria and lysosome-like bodies, are plentiful. Rough endoplasmic reticulum, polysomes and melanosomes while present are not abundant. Phagosomes of outer segment discs are noted in various stages of uptake and degradation. The choriocapillaris is highly fenestrated over large areas. Bruch's membrane shows the typical pentalaminate structure noted in other mammalian species without a tapetum lucidum.

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PubMed1987

Photoreceptor fine structure in the vervet monkey (Cercopithecus aethiops).

The structure of the photoreceptors of the vervet monkey (Cercopithecus aethiops) has been investigated by light and electron microscopy. In this species the photoreceptors can be readily differentiated and adequately described by the classical terminology of rods and cones, with rods being the more numerous. Rods are long, slender cells while cones are shorter and stouter. Both rods and cones are highly differentiated cells and consist of an outer segment, a connecting cilium, and inner segment, a nuclear region and a synaptic process leading to a synaptic ending. Morphological differences are noted between rods and cones for the various regions of these cells.

Animals↗
PubMed1982

[Cell kinetics and radiosensitivity of Cercopithecus aethiops sabaceus lymphocytes stimulated by phytohemagglutinin].

The use of the BudR-Giemsa technique has shown that the peripheral blood lymphocytes of Cercopithecus aethiops sabaceus display a very fast answer to PHA-stimulation. At 32 h culture time numerous mitoses are already present and at 48 h more than 30% of the dividing cells are in second mitosis. Exposure to X-irradiation results in a higher incidence of unstable aberrations than in human lymphocytes.

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PubMed1984

Pathologic changes of experimental simian varicella (Delta herpesvirus) infection in African green monkeys (Cercopithecus aethiops).

Gross and microscopic lesions of experimental simian varicella (Delta herpesvirus) infection in African green monkeys (Cercopithecus aethiops) are described. In stratified squamous epithelium, such as the epidermis, tongue, and esophagus, focal areas of epidermal hyperplasia, ballooning degeneration, and blood-filled vesicle formation with ulceration were apparent. Most visceral organs were involved, and the changes included necrosis, hemorrhage, and characteristic intranuclear eosinophilic inclusions in a variety of cells. A generalized vascular involvement was present with intranuclear inclusions in the endothelial and smooth muscle cells in various organs. The nervous system was normal on gross and microscopic examination. Virus titer and serum transferase values were correlated with the clinical signs of infection.

Animals↗
PubMed1980

Eosinophilic, electron-dense bodies in the tongue of Cercopithecus pygerythrus.

Dorsal glossal mucosa from healthy southern African vervet monkeys (Cercopithecus pygerythrus) invariably contained intra-cytoplasmic eosinophilic bodies in the prickle cells between and beneath the filiform papillae. Ultrastructurally, the bodies were relatively homogeneous, electron-dense structures of varying size and resembled structures previously described as keratohyaline in the hamster and the dog. No similar bodies were found in tongues from humans and Cape chacma baboons.

Animals↗
PubMed1995

Age-related expression of the CD15 (3-fucosyl-N-acetyl-lactosamine) epitope in the monkey (Cercopithecus aethiops aethiops L.) lateral geniculate nucleus.

The profile of the CD15 epitope-expression was studied in the lateral geniculate nucleus (LGN) of a monkey species (Cercopithecus aethiops aethiops L.) during the peri- and postnatal development. Intense labeling of the neuropil and of astroglial cells was detected. Morphological examination of the spatio-temporal appearance of the CD15-expression showed different consecutive patterns of expression: expression of the CD15 epitope was high one week prenatally and during the first postnatal weeks. During this perinatal period it was mainly expressed in the interlaminar zone of the magnocellular portion of the LGN. This was followed by a time period when immunoreactivity gradually decreased to become almost absent by approximately 10 weeks of age. Toward adulthood a different pattern of immunoreactivity occurred, revealing a pattern of lamination that was attributable to CD15 positive astrocytes, most prominent in the cellular layers 1 and 2. They were later on seen spread out through the entire LGN such that the LGN of adult animals was entirely filled with positive material. From the temporal correlation of CD15-expression and LGN histogenesis it is concluded that the high level of CD15, that is observed in the neuropil during the perinatal period, matches with high synaptic plasticity within the visual system; in contrast, low levels of CD15-expression correlate with synaptic reorganization processes.

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PubMed1994

Trypanosoma brucei rhodesiense: use of an antigen detection enzyme immunoassay for evaluation of response to chemotherapy in infected vervet monkeys (Cercopithecus aethiops).

Thirty eight Trypanosoma brucei rhodesiense-infected vervet monkeys (Cercopithecus aethiops) in the late (meningoencephalitic) stage of disease, treated with various trypanocidal drugs, were monitored for a period of more than 600 days to assess the rate of clearance of trypanosome antigens from serum and cerebrospinal fluid (CSF). There was a complete but gradual reduction in antigen titres, as assessed by ELISA, in animals treated intravenously with melarsoprol, the standard drug for the late stage disease. In 8 of the 9 monkeys treated with melarsoprol, the antigen titres, as assessed by optical density values, dropped by 50% within 252 days (mean value 68 days for antigens in CSF and 116 for serum) following treatment. The remaining animal in this group, that displayed persistent antigenaemia, had been treated with a sub-curative drug dosage level. Thus, if time to 50% reduction in antigen levels were to be taken as an index to predict cure, the follow-up period after melarsoprol treatment could have been reduced from 600 to 252 days for 8 of the 9 animals, leaving only one animal for further follow up. The animals treated with experimental drug combinations displayed a variable picture. Five monkeys showed a persistence of antigens in both serum and CSF throughout the observation period, suggesting failure of the drugs to cure the infection. Parasitologically confirmed relapse of the infection was indeed observed in all the five monkeys. In some monkeys, the parasite antigens eventually cleared from serum and CSF completely, but this took a longer time duration than in the melarsoprol treated animals; others showed persistence of parasite antigens in serum, but the parasites were not detected in blood or CSF throughout the entire follow-up period. These results suggest that the experimental drug combinations used were not effective in clearing the parasites from cryptic foci and hence the persistence of antigens in serum and/or CSF.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1993

Comparative susceptibility of African green monkeys (Cercopithecus aethiops) to experimental infection with Leishmania leishmania donovani and Leishmania leishmania infantum.

The leishmaniases are global health problems that affect both humans and animals. The availability of nonhuman primate models is desirable for such important areas as testing candidate vaccines and newly developed chemo- and immunotherapeutic agents. Visceral leishmaniasis was experimentally induced in African green monkeys (Cercopithecus aethiops) by intravenously inoculating 10(7) amastigotes/kg of body weight of either Leishmania leishmania donovani of human origin (group 1) or L. l. infantum of canine origin (group 2). The infected monkeys were monitored for 12 weeks. The monkeys developed persistent infections, became emaciated, and lost between 9 and 22% of their body weights. Splenomegaly developed by 6 to 10 weeks postinfection. All infected monkeys developed normocytic, normochromic anemia (3.5 to 3.8 x 10(6)/microliters), leukopenia (3,000 to 3,700/microliters), and neutropenia of varying severity. Hyperproteinemia with hyperglobulinemia (5.22 to 6.12 g/dl) was present in all monkeys to various degrees. Antibody responses gradually increased to peak values at 2 weeks postinfection in the L. l. donovani group and by 6 weeks postinfection in the L. l. infantum group. Lymphocyte blastogenesis proliferation responses were mildly decreased in all infected monkeys at 10 to 12 weeks postinfection. Parasite numbers were consistently higher in the livers than in spleens, and parasites were present in smears or cultures of the liver, spleen, bone marrow, and lymph nodes. Contrasting data between the two groups included 20-fold-higher parasite numbers in the livers (3.23 to 9.48 x 10(9)) and 39-fold-higher parasite numbers in the spleens (6.7 x 10(8) to 2.69 x 10(9)) of group 1. Granulomatous inflammatory reactions of various severity and intensity were observed in the liver, spleen, lymph nodes, thymus, and bone marrow of all infected monkeys. Within the granulomatous inflammatory reactions, clusters of macrophages, often containing amastigotes, were present. The morphologic changes in the bone marrow suggested a myelophthisic disease and those in lymph nodes and spleen suggested a B-cell proliferation. The clinicopathologic changes, mild suppression of cell-mediated immunity, and high antibody response in all infected monkeys indicated that African green monkeys can be a useful laboratory model for studying the clinicopathologic and immunopathologic changes induced by both L. l. donovani and L. l. infantum.

Animals↗
PubMed1996

Effect of protein deficient cassava diet on Cercopithecus aethiops hearts and its possible role in the aetiology and pathogenesis of endomyocardial fibrosis in man.

Despite the current hypotheses for its causation, the exact cause of endmyocardial fibrosis is unknown. However, endomyocardial fibrosis being a disease of the low socio-economic groups who feed on low protein high carbohydrate diets consisting exclusively of cassava in Uganda and the demonstration by the author of a bimodal age distribution among the female patients and monomodal pattern in the male patients, led the author to suspect protein deficiency and cassava as aetiological factors thereby attributing the first mode to the increased but unmet protein needs for childhood growth and the second mode to the increased but unmet protein needs for pregnancies and lactation in the 20-40 year age groups. Consequently a new hypothesis that "prolonged ingestion of tuber (cassava/tapioca) crops associated with extreme deprivation of protein causes EMF" was formulated. In order to verify this hypothesis, three Cercopithecus aethiops were fed on uncooked banana diet while another three were fed on uncooked cassava and hearts harvested for histology whenever the animal health deteriorated. Changes in the endomyocardium included cell vacuolation, interstitial fibrosis and endocardial thickening by the 130th day in the animals on cassava but the animals on bananas were free from such changes. By the 160th day, the former exhibited marked thickening of the endocardium, interstitial fibrosis, fibrous septa formation, pappillary muscle fibrosis as well as apical fibrosis of the left ventricle, which findings occur in the human disease. Calcification and inflammatory cells were absent. A repeat of the experimental feeding with cassava using a batch of five animals, one of which survived up to seven months revealed cardiac findings similar to those seen at 160 days. Thus, the pathogenetic process, hitherto obscure, begins with cardiac cell necrosis followed by fibrosis consequent upon the failure of cardiac cell repair due to protein deficiency caused by the protein free cassava diets since the animals on bananas, which also lacked protein did not develop similar changes. The low plasma amino acid profiles in EMF prone subjects, the poor blood supply and the great apical mechanical stress are incriminated for the severe apical lesions. This study shows that the disease can be experimentally induced in the monkey thereby validating the postulated hypothesis.

Adolescent↗
PubMed1996

Effects of cassava diet on Cercopithecus aethiops livers: a case for cassava as the cause of both tropical splenomegaly syndrome (TSS) and endomyocardial fibrosis (EMF).

The aetiology of endomyocardial fibrosis (EMF) and tropical splenomegaly syndrome (TSS) though speculative, was considered by the author to be the same or related since the two diseases may occur in the same individual and locality. Accordingly, when attempting to prove a hypothesis for the causation of EMF that prolonged ingestion of tuber (cassava/tapioca) associated with extreme deprivation of protein causes EMF; one group of three Cercopithecus aethiops was fed on uncooked cassava while a second group was fed with uncooked bananas and in addition to harvesting the hearts whenever the animal health deteriorated, livers were also harvested for histological changes. While hearts from the animals on cassava revealed changes seen in human EMF the livers from the same animals exhibited Kupffer cell hyperplasia and hypertrophy as well as sinusoidal lymphocytosis, features seen in human TSS thereby confirming that the aetiology of these two diseases is the same. However, the banana diet did not produce such changes.

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PubMedDate not supplied

[Relationship between the level of specific antibodies with disease outcome in Cercopithecus aethiops monkeys in experimental Marburg disease].

The level of specific antibodies in the blood of Cercopithecus aethiops monkeys with experimental Marburg hemorrhagic fever appreciably affects the incidence of lethal outcomes in immunized animals infected with Marburg virus. This effect manifests starting from the titers as low as just 1:100. The level of humoral immunity with the specific antibody titer of at least 1:100 depends on the method of antigen preparation. Humoral response was higher upon challenge with formalin-inactivated virus isolated from the blood plasma of infected guinea pigs.

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PubMed1999

Seed handling in chimpanzees (Pan troglodytes) and redtail monkeys (Cercopithecus ascanius): implications for understanding hominoid and cercopithecine fruit-processing strategies and seed dispersal.

Primates are confronted with an array of constraints in feeding on fruit, including the removal of adhesive, energy-rich pulp from seeds. In this paper, I discuss how primates meet this challenge and present data on the fruit-processing and seed-handling behavior of chimpanzees and redtail monkeys in Kibale National Park, Uganda. These data are then related to these species' services as seed dispersers. Particular attention was paid to the methods by which primates removed pulp from seeds, the density of seed clumps that they deposited (by spitting, dropping, or defecating) to the forest floor, and the distance seeds were moved from parent trees. Distance and density differences in chimpanzee and redtail seed dispersal resulted from distinct fruit-processing and seed-handling methods. It was observed, in general, that redtail monkeys engaged in fine oral processing and were seed spitters: most seeds were dispersed in close proximity to parent trees (84% of spat seeds < 10 m of parent tree), and deposited singly (100% seeds spat singly). In contrast, chimpanzees were coarse fruit processors and seed swallowers: seeds were defecated in denser clumps (e.g., a mean of 149 large seeds/dung sample and hundreds of small seeds/dung sample), far from parent trees. I evaluate the factors that shape patterns of fruit processing in hominoids and cercopithecines, and argue that the observed seed handling differences can be attributed to differences in digestive retention times, oral anatomy, and alternative mechanisms by which to avoid the cost of seed ballast.

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PubMed2000

Foraging ecology of the mountain monkey (Cercopithecus l'hoesti): implications for its evolutionary history and use of disturbed forest.

We present the first systematic field study on the feeding ecology of the mountain monkey (Circopithecus l'hoesti), a semi-terrestrial guenon. We compare our results with findings from a concurrent study of blue monkeys (C. mitis doggetti, which have an overlapping home range) conducted over ten months in the Nyungwe Forest Reserve, Rwanda. The mountain monkeys spent 35% of observation time feeding on terrestrial herbaceous vegetation. Thirty-five fruit and seed species comprised 42% of their diet, and invertebrates composed 9%. They spent 38% of observation time on the ground and 27% of observation time in canopy trees. Individuals were observed for equivalent proportions of time foraging on the ground for herbs and in canopy trees for fruits. Although mountain monkeys primarily foraged in undisturbed open areas, they also used disturbed open habitats for this purpose. Synthesizing our results with Pleistocene forest history and C. l'hoesti evolutionary history, we suggest that, although these monkeys readily use disturbed forest for herb foraging, they are a forest-adapted species which has adopted a terrestrial lifestyle to exploit the abundant herb layer common to montane forests.

Animals↗
PubMed1990

Angiology of the brain of the baboon Papio ursinus, the vervet monkey Cercopithecus pygerithrus, and the bushbaby Galago senegalensis.

The investigation was undertaken to compare the blood supply and venous drainage of the brain of the baboon P. ursinus, the vervet monkey C. pygerithrus, and the bushbaby G. senegalensis with that of man, because these animals are extensively used as research models. The blood supply of the three primates was found to be similar in each case. Like man they have a complete circulus arteriosus; but they have a single anterior cerebral artery, whereas man has paired anterior cerebral arteries. The arterial supply to the cerebellum in the primates is similar to that in man, the main difference being a "common inferior cerebellar artery" which bifurcates to form the anterior inferior cerebellar and posterior inferior cerebellar arteries. In man, these arteries arise separately from the basilar artery and vertebral arteries, respectively. The dural venous drainage was also found to be similar in these primates but was far more extensive than in man. The primates have additional sinuses--the more important of these being the "basisphenoid sinus" and the petrosquamous sinus. The former drains the basilar sinus and is itself drained via the vertebral venous plexus and internal jugular vein. The latter drains via the petrosquamous foramen into the retromandibular vein. The petrosquamous sinus has a rostral extension which drains through the foramen ovale and two lateral and medial connecting sinuses which drain the cavernous and basilar sinuses, respectively. These sinuses are not found in man.

Animals↗
PubMed1976

The cephalometric analysis of Cercopithecus aethiops.

A Steiner-based cephalometric study of 46 adult Vervet monkeys was undertaken using craniometric points as closely correlated to those in the human as possible. On tracings of each cephalogram 13 measurements were recorded. The results were statistically analysed. Whilst the monkey face does vary individually this variation is apparently much less than is that of the human face. It is possible that the positions of the monkey incisor crowns bear a relatively constant relationship to the soft tissue profile. The establishment of some cephalometric norms for the Vervet monkey may be useful for future growth studies.

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PubMed1989

Role of supraspinatus in the quadrupedal locomotion of vervets (Cercopithecus aethiops): implications for interpretation of humeral morphology.

Various researchers have noted that terrestrial and arboreal monkeys often differ in the degree to which the greater tubercle of the humerus projects proximally beyond the profile of the humeral head. These differences have been associated with differing leverage requirements for supraspinatus during quadrupedal locomotion. Although Jolly (The Baboon in Medical Research, Vol. II., pp. 23-50, 1967) suggested that a projecting tubercle can be related to the ability of supraspinatus to control more exactly the passive humeral retraction that occurs during support phase of quadrupedalism, most workers emphasize a link between this bony trait and the need for powerful or rapid protraction of the forelimb during swing phase of terrestrial quadrupedalism. We report on an EMG analysis of supraspinatus function showing that the muscle does not act as a brachial protractor during quadrupedalism, even in the relatively cursorial vervet monkey. We suggest that differences in greater tubercle projection can be related to the degree of mobility of the shoulder, and that supraspinatus size is determined by the interaction of greater tubercle height, adaptive importance of brachial elevation, and body size.

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