Massive endometriosis in two rhesus monkeys

Massive endometriosis was found in two rhesus monkeys during a chronic toxicological experiment. These cases had metastatic lesions in lymph nodes in addition to the foci on the serosal wall of pelvic organs. Invasion to the intestinal mucosal layer was also noted in a case. These observation indicated that endometriosis in the rhesus monkey might behave like a malignant neoplasm.     

Hydranencephaly in two rhesus monkeys (Macaca mulatta)

Spontaneously occurring hydranencephaly was diagnosed at necropsy and confirmed histologically in two stillborn fetuses that were delivered from young female rhesus macaques (Macaca mulatta).     

Self-agency in rhesus monkeys

Rhesus monkeys (Macaca mulatta) have shown the ability to monitor their own mental states, but fail the mirror self-recognition test. In humans, the sense of self-agency is closely related to self-awareness, and results from monitoring the relationship between intentional, sensorimotor and perceptual information. Humans and rhesus monkeys were trained to move a computer icon with a joystick while a distractor icon partially matched their movements. Both humans and monkeys were able to monitor and identify the icon they were controlling, suggesting they have some understanding of self-agency.     

Endocardiosis in rhesus monkeys

Endocardiosis was diagnosed as an incidental finding in two rhesus monkeys. The gross and histologic appearance of the lesions was described, and the similarity of this lesion to lesions of endocardiosis as found in dogs and man was discussed.The animals used in this study were handled in accordance with the Guide for Laboratory Animal Facilities and Care established by the National Academy of Science, National Research Council.     

Dominance order reversal between two groups of free-ranging rhesus monkeys

A rank reversal between two groups of free-ranging rhesus monkeys (Macaca mulatta) was observed.The group which became dominant through the reversal had been transplanted from another free-ranging colony eight months before. The actions of peripheral adult males of this group were important in effecting the reversal. Support of the peripheral males by the rest of the group was crucial in effecting the reversal.The development of the reversal indicates that social tradition and individual relationships between monkeys are important in maintaining and establishing intergroup rank.     

Cholesterol absorption and turnover in rhesus monkeys as measured by two methods

We compared the absorption of cholesterol in seven rhesus monkeys (four high-responders and three low-responders) as measured by two methods: 1) the dual isotope plasma ratio method of Zilversmit (1972. Proc. Soc. Exp. Biol. Med. 140: 862) and 2) the single isotopic meal feeding technique of Borgstr?m (1969. J. Lipid Res. 10: 331). We also compared the cholesterol pool sizes calculated by kinetic analysis of the plasma cholesterol specific activity decay curves obtained after simultaneous administration of [(3)H]- and [(14)C]cholesterol, one given intravenously and the other orally. The ratio of orally to intravenously administered cholesterol radioactivity in plasma did not attain constancy until 6 weeks after isotope administration. Therefore, the percent absorption of cholesterol was calculated by the Zilversmit method 8 weeks after the administration of isotopes. The mean percent absorption of cholesterol by the Borgstr?m method was 66.3 +/- 5.1 (S.E.) and by the Zilversmit method was 70.3 +/- 7.4. The differences were not statistically significant. However, in two of seven monkeys the percent absorption of cholesterol calculated by the Zilversmit method was higher by 10.4 and 22.6 percentage points than the values obtained by the Borgstr?m method. Cholesterol absorption by either method was higher in the high-responding monkeys than in the low-responding group. The sizes of the rapidly exchangeable pool or the minimum estimate of the total body pool of cholesterol were similar for all monkeys or for either the low-responding or the high-responding animals and were also similar when calculated using the data from either the orally or the intravenously administered radioactive cholesterol. Cholesterol synthesis was significantly higher in the low-responding monkeys (115 mg/day) than in the high-responding (64 mg/day). The present study and our previous studies support the hypothesis that a major factor causing the difference in response of plasma cholesterol to dietary cholesterol between the high- and low-responding rhesus monkeys is a difference in the intestinal absorption of cholesterol.-Bhattacharyya, A. K., and D. A. Eggen. Cholesterol absorption and turnover in rhesus monkeys as measured by two methods.     

Menopause in female rhesus monkeys

Fifteen female rhesus monkeys (Macaca mulatto), ranging in age from 8 to 34 years, were studied for one year to characterize the endocrine and menstrual changes associated with menopause in this species. Five monkeys were premenopausal; these younger monkeys, ages 8–11 years, menstruated and showed cyclic ovarian activity during the 12–month study period, as evidenced by menses and periodic elevations of serum estradiol (E₂) and luteinizing hormone (LH) concentrations. Four females, ages 24–26 years, were in transition to menopause. Two of these perimenopausal females menstruated and secreted E₂ and LH in a periodic fashion; the other two females showed elevated LH concentrations, consistently low E₂ levels, and no evidence of menstruation. Six females, ages 27–34 years, were clearly postmenopausal; LH concentrations were high, whereas E₂ concentrations were uniformly low. There was a significant inverse correlation between basal E₂ concentrations and age, and a significant positive correlation between age and LH concentrations across all 15 animals. Hormonal changes indicative of ovulation, when they occurred, were generally restricted to the winter and early spring months. Histological analysis of ovaries from four postmenopausal females revealed little or no evidence of active folliculogenesis. These data indicate that menopause in female rhesus monkeys does not occur until the second half of thethird decade of life. © 1995 Wiley-Liss, Inc.     

UDP-glucuronyltransferase activity exhibits two developmental groups in liver from foetal rhesus monkeys.

UDP-glucuronyltransferase was assayed in liver from adult rhesus monkeys and foetuses during late gestation. Activities toward 2-aminophenol, 5-hydroxytryptamine, 1-naphthol and 4-nitrophenol in the foetal liver ranged from 46 to 114% of adult values, whereas activities toward bilirubin, oestradiol and testosterone were less than 5% of adult values. This suggests that in primates UDP-glucuronyltransferase develops differentially in two clusters analogous to that in the rat.     

Replication of herpes simplex virus in two cell systems derived from rhesus monkeys

The replication of herpes simplex virus (HSV) in two cell systems derived from rhesus monkeys (LLC-MK2 and DBS-FRhL-2) was studied. In LLC-MK2, the growth of HSV-1 was abortive or extremely limited regardless of the multiplicity of infection, while that of HSV-2 was productive only on infection at high multiplicities. DBS-FRhL-2 cells supported growth of both types of HSV, although growth was highly dependent on the age of monolayers and the infectious dose of virus inocula. Plaques were produced in DBS-FRhL-2 cell monolayers inoculated with HSV-2 but not with HSV-1, although the efficiency of their formation in the former system was much less than in a system of FL and HSV-2. On the other hand, plaques were not produced in LLC-MK2 cell monolayers by either type of HSV. The growth of adapted variants of HSV-1 was also studied. In contrast to the parental strain, these variants replicated well in LLC-MK2 even at a low multiplicity of infection and produced clear plaques in the monolayers. Furthermore, persistent infections of HSV-2 were established in DBS-FRhL-2 cell monolayers under routine culture conditions.