Primates in medicine最新文献

Brain homogenates (10% w/v) from five of seven kuru patients inoculated intracerebrally (i.c., 0.1 ml) into marmosets (Saguinus sp.) induced a rapidly progressive CNS disease 26, 31, 36, 76 and 94 months postinoculation. Serial marmoset passages of kuru were accomplished by i.c. inoculation of neonatal marmosets with brain homogenates from marmosets with experimentally induced kuru. The incubation periods ranged from 1.5 to 11 months (average 7.3) in 19 animals, 20-25 months in four animals and greater than 26 months in two animals. Symptoms and brain lesions of the induced disease were compatible with kuru as observed in humans and other nonhuman primates. Creutzfeldt-Jakob disease (CJD) has been induced by i.c. inoculation of marmosets with brain homogenates from two of four human CJD patients with incubation periods of 43 and 54 months and is in serial passage.

The inoculation of a cotton-topped marmoset with B95-8 strain of EBV resulted in the induction of a multifocal lymphoma and lymphoblastoid cell lines were established from liver, spleen and mesenteric lymph node tumors. The cell lines were remarkably similar to each other with respect to the presence of EBV and its expression, the surface properties of the cells and their stability, and the functional products of the cells. Karyotypic examination of the cell lines revealed the common loss of a single chromosome. The slight differences noted in karyotypes suggest some divergence from a tumor stem cell and imply a clonal origin. Thus, EBV-induced lymphomas in cotton-topped marmosets resemble Burkitt's lymphoma in man.

The field studies reviewed above raise some doubts about the laboratory concept of the extended family as the basic social unit of the Callithricidae. As Dawson [6] suggests, wild groups might more closely approximate artificial laboratory groups. They probably consist of a dominant, monogamous breeding pair, its dependent offspring and separate hierarchies of subdominant males and females who stay associated with the group for various lengths of time. Some of these subdominants might be offspring or relatives of the breeding pair. As the field studies show, these groups are more or less open to immigrants coming from other groups. They possibly tolerate transient relatives more easily and for longer periods of time than nonrelated individuals. In spite of the relative tolerance of wild groups towards strange conspecifics, it appears most practical to maintain laboratory breeders as families and remove the offspring after they have participated in the care of their younger siblings. In this way their reproductive capacities can be utilized as soon as their parental behavior has developed adequately. Moreover, possible losses caused by keeping nonrelated adults of the same sex together are avoided. As pointed out above, some species are very aggressive towards strange adult conspecifics and some seem to defend territories in the wild. It seems advisable therefore to house them in cages which provide a certain degree of isolation from neighboring groups. We have found this to be more important in S. fuscicollis than in C. jacchus, particularly in densely populated colony rooms. We therefore house our animals in cages which allow no visual contact with any other group, and by doing so have reduced the general level of excitement in the colony room. We believe that aggressive displays between groups are responsible for a large amount of redirected aggression between mates and for some of the abortions we have seen in our colony. Moreover, Rothe's [28, 29] observation that the parturient female withdraws from her group and gives birth in relative isolation should be taken into consideration when designing breeding cages. Although not all individuals of all species might show this behavior [see 32] it seems to be widespread enough to be an important factor in breeding efficiency and might figure in some of the infanticides observed by us and other authors.

The induction of chromosome aberrations by low LET radiations was studied in peripheral lymphocytes and spermatogonial stem cells of the male marmoset. The data showed that there was not significant difference in the sensitivity of the lymphocytes whether they were irradiated in vitro or in vivo, but the frequency of heritable translocations recovered in the primary spermatocytes were considerably lower than that calculated to occur in the lymphocytes. The data are used to make estimates of human genetic risk from radiation based on limited interspecific comparisons.

Using skin test response and lymphocyte blastogenesis as indicators of cell-mediated immunity, we have been able to demonstrate in vivo transfer of cell-mediated immunity to marmosets both with dialyzable transfer factor (TFd) prepared from a human donor and transfer factor (TF) from baboon whole cell lysates. We were able to protect marmosets with TFd from fatal Herpesvirus hominis type 1 (HVH-1) disease. When TFd was administered prior to challenge with HVH-1, 50% of the marmosets survived. Of the untreated control animals and those first treated on day 0 or postinfection, 100% succumbed to disseminated HVH-1 disease. In addition, when TF prepared from TFd-treated marmosets which had survived HVH-1 disease, was given to other marmosets, it conferred protection from subsequent HVH-1 challenge.

The rufiventer marmoset proved equally satisfactory to S. mystax for studies of human hepatitis A virus. C. jacchus, C. argentata, S. weddelli, and S. oedipomidas oedipus were not satisfactory. Livers of rufiventer marmosets produced satisfactory CR326 strain hepatitis A antigen for immune adherence tests both in amount and specificity. Rufiventer marmosets infected with human hepatitis A virus showed enzyme elevations and high titers of viral antigen in their livers as early as seven days after viral inoculation, indicating that a primary viral infection can cause hepatitis without need for a secondary autoimmune response to liver tissue.

Marmoset lymphocytes were highly reactive to general mitogens, participate in direct cytotoxicity (purportedly mediated by T-cells) and particpate in an antibody dependent lymphocyte cytotoxicity assay (K-cell). The distribution of lymphocyte subpopulations among various species showed that the percent T-cells ranged from 46.4 to 66.6% in different species while complement receptor cells ranged from 10.3 to 19.0%. Surface immunoglobulin (SIg) stable B-cells ranged from 10.6 to 16.4% while the SIg labile L-cells ranged from 26.9 to 37.5%. A fourth receptor, Fc, was demonstrated on 23.7 to 31.7% of the marmoset lymphocytes.

Brazilian and Guianan callitrichids are categorized as endangered, vulnerable, common or status unknown. Endangered species should not be used in biomedical research and a continuing supply of wild-caught vulnerable species is also out of the question. Common species, on the other hand, could withstand limited sustained yield cropping without difficulty. Species categorized as status unknown should not be used until more data on them become available. Callitrichids have a higher reproductive potential than other New World monkeys, are for the most part quite adaptable, and are rarely hunted for food or captured as pets locally. Widespread habitat destruction is the major threat to their survival and species with naturally small ranges in areas of high human activity (e.g. Leontopithecus, Callithrix flaviceps) are in the greatest danger.