Reproductive and hormonal patterns in the African green monkey (Cercopithecus aethiops).

The results of breeding Cercopithecus aethiops under time-mated laboratory conditions and analysis of total estrogen, progesterone, and LH concentrations in plasma during the menstrual cycle and plasma estrogen and progesterone concentrations during pregnancy indicate that this species is a suitable alternative for the rhesus monkey as a model for investigations of reproductive function in man.     

Early placentation in the African green monkey (Cercopithecus aethiops)

Placentation in the green monkey (Cercopithecus aethiops) from gestational ages of 18-30 days was studied by light and electron microscopy. The placentae show many features in common with that of the rhesus monkey and other related macaques. Implantation is superficial and bidiscoid, and the placenta is classified as villous and hemomonochorial. Epithelial plaque formation and a moderate stromal reaction occur. Plaque cells are large, with massive deposits of glycogen and marginal pleomorphic dense bodies. Observations further support the concept that chorionic blood vessels, angioblastic and mesenchymal cells are not derived by delamination from cytotrophoblast. Capillary formation is by attachment of one or more mesenchymal cells and/or their processes. Embryonic blood was not observed in the villi until after day 22.     

Ultrastructure of sensory nerve terminals in the penis in green monkey (Cercopithecus aethiops sabaeus).

Tje paper describes the ultrastructure of axons in the endings of various types from the corium in the glans penis in green monkey. In the Meissner's endings the axons are mostly completely enveloped in the plasma of Schwann cells. They contain numerous mitochondria which are partially vacuolated or are quite converted into vacuoles. Next, there are pseudomyelinated figures, light vesicles and further organelles. In the papillar simple glomerular endings with accumulation of Schwann cells there are axons irregular in shape, eccentrically placed in the plasma of Schwann cell, rounded smaller axons either completely or partially surrounded by the plasma of Schwann cell and finally axons with a concentric system of lamellae up to four in number, In the complicated glomerular endings the axons vary in appearance and are enveloped in one to five lamellae of Schwann cells, which is typical of those formations. About some of these systems there is a sign of a capsule formed by an elongated lamella probably of the perineurium. When the axons are not enveloped in the plasma of Schwann cell, they are covered by the basement membrane. In close neighbourhood of the epidermis so-called free endings forming groups were found. The plasma of Schwann cell covers them either partially or completely or it again forms around them a lamellar system amounting up to four layers. It is noticeable that these axons are very poor in organelles. A comparison of the simple sensory corpuscles in the nose skin in hedgehog, the funtional properties of Meissner's endings and the simple corpuscles results in the view that the complexes having a larger amount of lamellae correspond to an extent to the simple sensory corpuscles ant that the Meissner's endings and the complicated glomerules are probably a morphological and functional equivalent of simple sensory corpuscles in the non-primate mammals and that the gloverular endings may also be the first (developmental) stage of the simple sensory corpuscles.     

Circadian rhythm of cholesterol-7alpha-hydroxylase and cortisol in the African green monkey (Cercopithecus aethiops).

Cholesterol-7alpha-hydroxylase in African green monkey liver had an apparent Km of 1.65-10(-4) M cholesterol and a pH optimum of 7.4. The amplitudes of the circadian maxima of enzyme activity and serum cortisol levels were significantly greater in vervets than in grivets. Fluctuations in enzyme activity and cortisol levels during the circadian cycle were positively correlated (r = 0.89). Enzyme activities and hormone levels were 2.7-fold lower over a 24-h period in the grivet than in the vervet. Cholesterol feeding reduced the enzyme activity by 40% and serum cortisol was reduced to 38% of control levels at the diurnal peak. Serum glucocorticoids may be important physiological regulators of cholesterol-7alpha-hydroxylase in non-human primates. The concentration of cortisol and its time of release appear to be factors in the hyperresponsive trait of grivets. Genetic differences between vervet and grivet races may account for differences in the amplitude and timing of the circadian rhythm of cholesterol-7alpha-hydroxylase activity possibly influenced by cortisol.     

Variable satellite DNA's in the African green monkey Cercopithecus aethiops

A heavy component of Cercopithecus aethiops DNA has been observed which comprises a small but variable portion of the monkey genome. This variability exists both within and among different monkey cell lines. In general, cell lines with larger amounts of this heavy component showed virus-induced host DNA synthesis on lytic infection with SV-40 virus. The heavy component, which has a buoyant density of about 1.711 g/ml in CsCl, consists of at least two minor satellite DNA's, designated components and . By in situ hybridization, component was localized to the pericentromeric heterochromatin of monkey chromosomes in all cell lines examined. In contrast, component sequences were scattered over the monkey karyotype. Component reassociated with more precision than component . However, neither component nor component reassociated as rapidly and completely as component , the major monkey satellite DNA which comprises 20–25 percent of the monkey genome.     

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.     

T-cell lymphosarcoma in a female African green monkey (Cercopithecus aethiops)

A female African green monkey developed a generalized lymphosarcoma spontaneously that clinically and pathologically resembled malignant lymphoma in human beings infected with human T-lymphotropic virus type I. The monkey was serologically positive for simian T-lymphotropic virus. Immunocytochemical analysis of routinely fixed and paraffin embedded tumor tissue demonstrated neoplastic cells that stained positive with antihuman monoclonal UCHL1 which recognized a T-cell-restricted isotype of leukocyte common antigen.     

Pulmonary immunoreactive calcitonin in the African green monkey (Cercopithecus aethiops): Anatomic distribution

The hormone calcitonin, which occurs predominantly within the C cells of the mammalian thyroid gland, is also found within the pulmonary endocrine cells of the epithelium of the tracheobronchial tree. A study was made of the distribution of immunoreactive calcitonin (iCT) in the African green monkey. Using two different region-specific antisera, the total respiratory iCT comprised 2.5% and 5.8% of the total thyroid iCT. The mean concentration of iCT in the right lung exceeded that in the left, and the mean concentration of the right middle or right upper lobe exceeded that of all other lobes. Embryologically, the ultimobranchial bodies contribute their iCT-producing C cell primordia to the thyroid gland near the level of the primitive laryngotracheal cleft and shortly after the early arborization of the bronchial tree. In monkeys and most other mammals, the right main stem bronchus is larger and develops earlier than the left. The data suggest an early migration of cells from the ultimobranchial bodies to the bronchi, eventually giving rise to the iCT-containing pulmonary endocrine cells.     

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.     

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.