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Ecological data about three free-ranging groups of C. penicillata (black-pincelled marmoset) were observed between March and December 1996, in one cerradão patch (in the Ecological Reserve of Brazilian Institute of Geography and Statistics, RECOR) and two patches of dense cerrado (one in the RECOR and another in the Botanical Garden of Brasília, JBB), situated in the APA (area of environmental protection) of the Gama/Cabeça-de-Veado, Distrito Federal. Each area was visited weekly during three periods of two months--end of the rainy season (01/04 to 31/05), dry season (16/06 to 15/08) and beginning of the rainy season (14/10 to 15/12)--and instantaneous scan records at fifteen minute intervals were made for the vertical and horizontal position of each visible individual of the target group. The group size ranged between 4 and 11 elements. In September, the birth of twins in both groups of the RECOR was observed. Home-range varied from 8.25 to 18.5 hectares, while density ranged from 0.4 to 0.82 ind/ha. Twenty two species of nine tree families were identified as exudate sources. Qualea grandiflora (Vochysiaceae), Vochysia thyrsoidea (Vochysiaceae), Scheflera macrocarpum (Araliaceae) and Qualea parviflora (Vochysiaceae) were more explored. Fruits (14 species, two of which were exotics), nectar, honey, arthropods (mainly orthopterans) and bird eggs complete their diet. The main sleep-tree species was Emmotum nitens (Icacinaceae). Data from different seasons and studied groups/areas were compared along previous data from this primate species in gallery forests. In the cerradão and dense cerrado areas C. penicillata had a similar group size, however a larger home-range and smaller density than in gallery forests were observed in this study.
A sex hormone binding globulin (SHBG) similar to human SHBG was identified in marmoset serum based on its gel electrophoretic mobility, isoelectric point and steroid binding properties. Levels of serum SHBG were measured in immature and mature males, immature females and females during the luteal phase and pregnancy; serum progesterone, 5 alpha-dihydrotestosterone (5 alpha-DHT), testosterone, oestradiol-17 beta and oestrone were also measured. Mean (+/- S.E.M.) concentrations of SHBG in immature males (336 +/- 19 nmol/l) were higher (P less than 0.01) than those in mature males (251 +/- 13 nmol/l), whereas values in the groups of females were similar (359 +/- 12, 395 +/- 17, 397 +/- 39 nmol/l in immature, non-pregnant and pregnant females respectively). There was an inverse relationship between SHBG and the levels of testosterone (r = -0.67) and 5 alpha-DHT (r = -0.86) in males, but the correlation was significant (P less than 0.05) only for 5 alpha-DHT. There was no correlation between levels of SHBG and oestrogens in males or between levels of SHBG and any of the steroids measured in females. Equilibrium dialysis was used to assess the percentage of steroid in serum in the unbound form. Mean percentage values for unbound testosterone and 5 alpha-DHT were lower in immature males than in mature males (P less than 0.01) and negatively correlated with levels of SHBG (r = -0.78, testosterone; r = -0.56, 5 alpha-DHT).
Unlike in other non-human primates, ovariectomy of the female marmoset did not alter heterosexual interactions. Proceptive behaviour bouts retained the same cyclicity, duration and frequency within tests as during the ovarian cycle. Significant rises in plasma levels of cortisol, progesterone, oestrone and testosterone were found during these proceptive behaviour bouts and in cortisol, progesterone and oestrone at their onset. Results suggest a role for adrenocortical steroids in both maintaining female sexuality and regulating its cyclicity during ovarian cycles in this primate.
The suppression of ovulation in subordinate female marmosets was associated with suppressed pituitary LH secretion and reduced pituitary LH response to gonadotrophin-releasing hormone (GnRH). In subordinate females, basal plasma LH concentrations were commonly below 2 IU/l (n = 5) (maximum 10.7 IU/l). Plasma oestrogen concentrations were similarly low (maximum 0.62 nmol/l) and plasma progesterone concentrations of below 30 nmol/l confirmed the anovulatory condition. This infertility condition was rapidly reversed when subordinate females (n = 5) were removed from their social groups and housed singly, when plasma LH (maximum 140.0 IU/l) and oestrogen (maximum 7.84 nmol/l) concentrations increased preceding ovulation. Infertility was rapidly reimposed when these singly housed females were re-introduced to subordinate status in new social groups, when plasma LH concentrations fell to their previous low values within 4 days; no ovulation occurred thereafter. Plasma oestrogen levels also fell, but less dramatically. The luteal phases of three of the subordinate females were shortened following the re-instatement of subordinate status. The maximum LH response of subordinate females to the highest dose of GnRH (200 ng) was only 19.1 +/- 6.7 IU/l (mean +/- S.E.M.; n = 8): this contrasted with that in dominant females in either the follicular phase (40.0 +/- 13.3 IU/l; n = 6) or the luteal phase (126.7 +/- 24.9 IU/l; n = 10) of the ovarian cycle. These results suggest that the social suppression of fertility in subordinate female marmosets is mediated by impaired hypothalamic GnRH secretion. Such an immediate and precise behavioural control of LH secretion and ovulation is without equal in anthropoid primates.
Stressful stimuli associated with aggressive encounters and low social rank may affect female fertility in a variety of mammalian species. In these experiments we examined the effects of aggressive encounters and physical restraint in a primate chair on the patterns of LH secretion in ovariectomized, oestrogen-primed female marmosets. Receipt of aggression from a female conspecific, followed by physical restraint for collection of blood samples (at 10-min intervals for 4 h), resulted in marked declines in LH concentrations during oestradiol-induced LH surges in five animals (from 112 +/- 24 micrograms/l to 45 +/- 12 micrograms/l; group means +/- S.E.M.; P less than 0.05). This was due to reductions in LH pulse amplitude rather than to changes in pulse frequency. Decreases in plasma concentrations of LH were reversed by treating females with exogenous LH-releasing hormone (LHRH). Cortisol treatment had no effect on LH levels during oestrogen-induced LH surges. Effects of aggressive encounters and physical restraint on plasma LH were not therefore due to reduced pituitary responsiveness to LHRH or to increased plasma concentrations of cortisol. In separate experiments it was found that physical restraint alone had no effect on plasma LH in habituated subjects, and that decreases in plasma LH after receipt of aggression only occurred if animals were subsequently placed in the restraint chair. A summation of stressful effects is therefore required to produce the fall in circulating LH. A summation of social and other environmental stressors may also underlie the reduced fertility seen in free-living animals.
The application of an in vitro microdialysis system (MDS) for studies on the gonadotrophic control of luteal progesterone secretion in the marmoset monkey is described. Luteal tissue collected from a total of six animals (9 +/- 1 days after ovulation) was perfused with Ringer solution (without and with lipoprotein, 0.6 microgram/ml). The tissue was exposed to repeated applications of human LH (hLH) and human chorionic gonadotrophin (hCG) (1, 10 and 100 IU/ml) each of 60 min duration. Perfusate was collected in 15-min fractions and assayed for progesterone content. Results showed that addition of lipoproteins to the Ringer solution had a marked effect of progesterone secretion in terms of maintaining stable baseline levels and improving reproducibility of gonadotrophin-induced responses. Progesterone secretion was significantly stimulated by both gonadotrophins at each dose tested. Maximal elevations were obtained with 10 IU/ml and there were no apparent differences in responses to hLH and hCG in terms of either magnitude or duration. This study indicates that MDS provides a useful in vitro approach for studying the gonadotrophic control of the corpus luteum in non-human primates. The results did not demonstrate disparate actions of hLH and hCG in their ability to stimulate luteal progesterone secretion.
The effects of the prostaglandins (PG) E2 and F2alpha on progesterone secretion in luteal tissue (32 corpora lutea) explanted from the mid-luteal ovary of the marmoset monkey (n=13) were investigated using an in vitro microdialysis system. Consecutive applications of 1, 10 and 100 microg/ml PGE2 resulted in a significant increase in secretion of progesterone at the maximum dose of 100 microg/ml, which was shown to be the stimulatory dose in both long-period and 20-min pulse (time to collect one fraction) applications. The response varied individually between 1.4- and 3. 4-fold above the baseline concentrations. Application of 500 microg/ml PGF2alpha led to similar hormone responses. In contrast, lower doses of PGF2alpha (0.5, 5 and 50 microg/ml) resulted in significantly increased levels of secretion of progesterone, to approximately 1.4-fold baseline values, only after the application was terminated (echo effect). Responses were less variable when a short pulse of 20 min duration was applied, instead of long applications of 1-2 h. On the basis of the passage rates measured for tritiated PGF2alpha, transfer through the dialysis membrane was assumed to be in the range of 1% for both PGs. Ultrastructurally, luteal cells lying in a sheath of five to seven cell layers around the dialysis tubing appeared intact and were interconnected by gap junctions. Vesiculation of the smooth endoplasmic reticulum was more prominent after PG treatment, indicating a stimulation of cellular synthesis/secretory activities that was in accordance with the stimulatory action of both PGs on progesterone release under these in vitro conditions.
Benzylmercapturic acid is a major metabolite of [methylene-14C]benzyl chloride in the marmoset, as in the rat. The excretion of the minor metabolites benzylmercapturic acid sulphoxide and benzylcysteine accounted for a greater proportion of the dose than in the rat. Excretion of hippuric acid as a metabolite of benzyl chloride was variable in the marmoset. Acetylation of S-benzyl- and S-pentyl-L-cysteine to the corresponding mercapturic acids was extensive in the marmoset. Trace amounts of the sulphoxides of these acids were also excreted.
Inhibition of CD40-CD40 ligand interaction is a potentially effective approach for treatment of autoimmune diseases, such as multiple sclerosis. We have investigated this concept with a chimeric antagonist anti-human CD40 mAb (ch5D12) in the marmoset monkey experimental autoimmune encephalomyelitis (EAE) model. Marmosets were immunized with recombinant human myelin oligodendrocyte glycoprotein (rMOG) and treated from the day before immunization (day -1) until day 50 with either ch5D12 (5 mg/kg every 2-4 days) or placebo. On day 41 after the induction of EAE, four of four placebo-treated monkeys had developed severe clinical EAE, whereas all animals from the ch5D12-treated group were completely free of disease symptoms. High serum levels of ch5D12 associated with complete coating of CD40 on circulating B cells were found. At necropsy placebo- and ch5D12-treated animals showed similar MOG-specific lymphoproliferative responses in vitro, but ch5D12 treatment resulted in strongly reduced anti-MOG IgM Ab responses and delayed anti-MOG IgG responses. Most importantly, treatment with ch5D12 prevented intramolecular spreading of epitope recognition. Postmortem magnetic resonance imaging and immunohistologic analysis of the CNS showed a markedly reduced lesion load after ch5D12 treatment. In conclusion, the strong reduction of clinical, pathological, and radiological aspects of EAE by ch5D12 treatment in this preclinical model points to a therapeutic potential of this engineered antagonist anti-CD40 mAb for multiple sclerosis.
PURPOSE: Experimental manipulations of visual experience are known to affect the growth of the eye and the development of refractive state in a variety of species including human and nonhuman primates. For example, it is well established that visual form deprivation causes elongation of the eye and myopia. The effects of such manipulations have generally been examined in neonatal or juvenile animals. Whether adolescent common marmosets (a new world primate) are susceptible to form deprivation myopia was studied. METHODS: Five adolescent marmosets were used in this study. Monocular form deprivation was induced by lid closure for 12 to 20 weeks, starting between 299 and 315 days of age. The effects of deprivation were assessed with keratometry, A-scan ultrasonography, and cycloplegic refractions. Both eyes (treated and fellow control) were measured before lid-closure, at the end of the deprivation period, and several times over the following 8 to 12 weeks. RESULTS: Adolescent marmosets are susceptible to visual form deprivation myopia. The experimental eyes showed significant axial elongation and myopia relative to the fellow control eyes. These changes were smaller, however, than those observed in younger eyes deprived for comparable periods. Like juvenile animals, the adolescent marmosets did not show recovery from myopia over the period monitored. CONCLUSIONS: The period for susceptibility to form deprivation myopia in the marmoset monkey extends beyond the early developmental period when ocular growth is rapid and emmetropization normally takes place. Visual form deprivation in adolescent marmosets with adult-sized eyes results in increased ocular growth and myopia. These data suggest that visual factors may influence the growth and refractive development of the human eye after puberty and may be involved in late-onset myopia.
The present study investigated the topographical distribution of P2X(1)-P2X(6) receptor subtypes in the rat and common marmoset hindbrain by immunohistochemistry. In addition, double-labeling immunofluorescence was used to determine the extent of colocalization between catecholamine cell groups and the various P2X receptors. The data demonstrate a widespread distribution pattern for all six P2X receptors throughout both the rat hindbrain and the marmoset hindbrain, although distinctions between species, brain nuclei, and P2X receptor subtypes exist. In rat, dense staining for the P2X receptors was found in the nucleus of the solitary tract (NTS), medial vestibular nucleus, and medial and lateral parabrachial nuclei. Moderate staining was observed in the hypoglossal nucleus, cuneate nucleus, inferior olive, prepositus hypoglossi, rostral ventrolateral medulla (RVLM), and locus coeruleus. Staining was also observed in the gracile nucleus, the mesencephalic trigeminal nucleus, and the central pontine gray. In marmoset, prominent P2X receptor-like immunoreactivity occurred in the NTS, medial cuneate nucleus, prepositus hypoglossi, and medial vestibular nucleus. Moderate staining was observed in the area postrema, dorsal motor nucleus of the vagus, lateral cuneate, lateral reticular, spinal trigeminal nucleus, RVLM, and inferior olive. Immunofluorescent double labeling of tyrosine hydroxylase (TH)-containing cells revealed that all subtypes of P2X receptors show some degree of colocalization with TH. The highest proportion of TH and P2X receptor double labeling was in the A5 region (with the P2X(2) subunit), whereas the lowest proportion of double-labeled cells occurred in the C2 region of the NTS for the P2X(5) subunit. These findings support a role for extracellular adenosine 5'-triphosphate in fast synaptic neurotransmission within the brainstem.
PURPOSE: The lacrimal gland is often selected for microscopic examination in toxicologic studies. However, this gland is difficult to find within the orbit in marmosets at necropsy. Therefore, we examined the extraorbital lacrimal glands in marmosets. METHODS: The formalin-fixed craniums of four marmosets were used in a topographic study to confirm location of the lacrimal gland, and the results were applied to a routine toxicologic study in marmosets. RESULTS: The extraorbital lacrimal gland was located on the temporal surface of the zygomaticofrontal process and was covered with the temporalis muscle. The gland was easily detached from the surrounding tissue, and its histologic features were the same as those of the intraorbital lacrimal gland. CONCLUSIONS: The extraorbital lacrimal glands have been reported in some New World monkeys, but to the authors' knowledge, this is the first report in marmosets. Identification and characterization of this gland will be useful for toxicologic studies in marmosets.
In the present study, changes in the immunohistochemical localization of endometrial estrogen receptor (ER) and progesterone receptor (PR) during various stages of the ovarian cyclicity in common marmoset, have been reported. Ovarian cyclicity was monitored by estimating plasma estradiol and progesterone. During the early follicular phase, weak ER immunolocalization was observed in the endometrial stroma. During the late follicular phase under the influence of rising estradiol levels, stromal ER localization was intense. During the luteal phase, ER localization was absent in the stroma indicating that high concentrations of progesterone suppressed ER. PR localization was not observed in the stroma during the early follicular phase, while weak staining was seen in the stroma during the late follicular phase. PR localization was maximum during the mid luteal phase. However in marmoset, endometrial ER and PR localization was restricted only to the stroma. This unique feature may be due to the characteristic reproductive profile of this nonmenstruating species and needs to be studied further. Thus it can be hypothesized that in the marmoset endometrium, steroid hormone mediated effects possibly occur directly in the stroma and are then transmitted to the epithelium by autocrine/paracrine action of growth factors and cytokines.
Few studies of body composition have been done in New World primates. In the study reported here, four methods of assessing body composition (body weight, anthropometry, labeled-water dilution, and total body electroconductivity) were compared in 20 marmosets, aged 0.96 to 7.97 years. Males and females did not differ in any measure (P > 0.05). Body weight ranged from 272 to 466 g, and body fat estimates varied from 1.6 to 19.5%. Strong positive correlations were observed between total body water and total body electroconductivity (R2 = 0.77), body weight and fat-free mass (males R2 = 0.95; females R2 = 0.91), and body weight and fat mass (males R2 = 0.86; females R2 = 0.85; P < 0.01). Male and female slopes were equivalent (P > 0.05) for the regressions of fat and fat-free mass against body weight. Positive correlations also were observed between girth measures and fat-free mass (R2 = 0.48 to 0.78) and fat mass (R2 = 0.60 to 0.74; P < 0.01). A good second- order polynomial relationship was observed between age and fat-free mass for the combined sample (R2 = 0.64). Results indicated that: subjects were lean; there was no sexual dimorphism relative to measures; body weight provided a reliable estimate of fat and fat-free mass; and within-subject body weight changes reflected a similar relationship between body weight and fat-free mass as did that across subjects.
The morphologic differentiation of Sertoli cells isolated from adult and juvenile marmosets and cultured on different extracellular matrices was evaluated by light and electron microscopy and compared to cells in vivo. Both cell types could be maintained in culture for at least 6 days. The degree of cellular differentiation, shape, ultrastructural appearance, and polarity seemed to benefit from laminin-coated substrata, compared with collagen-, fibronectin-, serum-, and heparan sulfate-coated substrata. With the former two substrates, a difference in behavior between juvenile and adult cells was evident. Whereas juvenile cells displayed a lesser degree of differentiation, adult cells exhibited identical morphologic characteristics in culture and in vivo. Cyclicity of morphologic features was not found, neither in vivo nor in vitro. The results indicate that: (1) laminin plays a unique role for marmoset Sertoli cell differentiation in vitro compared with other extracellular components; (2) a greater similarity between cells in vivo and in vitro is evident with adult Sertoli cells; and (3) the adult marmoset monkey could provide a primate model for mature Sertoli cells in culture, since there is a close similarity to human adult Sertoli cells in vitro and in vivo.
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Using specific polyclonal antibodies generated against a 13 Kd human testicular inhibin, immunocytochemical localization was carried out in epididymis of intact and castrated marmoset monkey and rat epididymis. Inhibin was found to be present in the cytoplasm of epithelial cells of caput, corpus and cauda epididymis. The intensity of staining and pattern of distribution did not change following castration. Further, the in vitro biosynthesis of inhibin studied by incorporating 3H-leucine and precipitating it with specific antibody indicated maximum biosynthesis in the corpus epididymis in case of marmosets and cauda in case of rats. Following castration in rats, the epididymal tissue still retained the capacity to biosynthesize inhibin. These studies indicate that marmoset and rat epididymis are capable of biosynthesizing/absorbing inhibin and whose synthesis does not depend on androgens.