Therapy of calcium oxalate urolithiasis in a rhesus macaque (Macaca mulatta)

A rhesus macaque (Macaca mulatta) was presented for anuria. Examination revealed calcium oxalate concrements in the bladder. A cystotomy was performed, and a therapy with alfuzosin was conducted. Over 1 year after the treatment, the rhesus macaque had not shown any more signs of stranguria. This is the first case reporting the successful treatment of urolithiasis in a rhesus macaque.     

Growth of the masseter muscle in rhesus monkeys (Macaca mulatta)

The growth of the masseter muscle in eight infant, juvenile, and adolescent female rhesus monkeys (M. mulatta) was examined over a 2.5 year period using serial radiographic cephalometric techniques with the aid of radiopaque muscle markers. The radiopaque markers, which are composed of small pieces of root canal broach inserted into the muscle belly, make it possible to determine longitudinal masseter muscle growth as well as migration of the masseter muscle relative to the mandible. It was found that the masseter muscle increased in length by 64% during the total growth period, most of which occurred between 6 and 18 months of age. Relative to the cranium, the masseter muscle grew markedly inferiorly and only slightly posteriorly. Relative to the mandible, the masseter migrated in a posterior and slightly superior direction, keeping pace with the ramus and condyle as they grew posteriorly and posterosuperiorly throughout the study period. It was concluded that: 1) radiopaque muscle markers are a valuable tool for analysis of muscle growth and alteration of muscle location; 2) the masseter muscle in the rhesus monkey undergoes elongation, probably due to addition of sarcomeres at the fiber-tendon junctions; and 3) posterior migration of the masseter muscle relative to the corpus of the mandible, probably due to the nature of its periosteal attachment, results in a stability of the anteroposterior position of the masseter muscle despite the anterior displacement of the mandible.     

Colon cancer in aged captive rhesus monkeys (Macaca mulatta)

The age-related incidence of malignant neoplasia was surveyed from a total of 301 necropsy cases of rhesus monkeys ranging in age from 13–37 years performed in the Pathology Service Unit of the Wisconsin Regional Primate Research Center during the past 15 years. All our aged monkeys lived in indoor cages and were fed with monkey chow and supplemental fruits during the past decades. In this survey, we found a total of 51 malignant neoplasms, and among them 25 cases were colon cancer. The incidence of colon cancer increased with advancing age: 3.2% at 13–19 years, 9.2% at 20–25 years, 13.5% at 26–29 years, and 20.7% at 30–37 years. Most cancers were located in the cecum and transverse regions with a unicentric origin. Two multicentric cases were associated with chronic hypertrophic colitis. Precancerous polypous lesions were not found in all cases. Histologically, all cases were mucinous adenocarcinoma and had local invasion to the muscular wall. Metastasis to the mesenteric lymph nodes was found in only two cases. As in humans, colon cancer is a common outcome of aging in nonhuman primates. Am. J. Primatol. 44:19–27, 1998. © 1998 Wiley-Liss, Inc.     

Gestation length in rhesus macaques (Macaca mulatta)

We describe some of the sources of variation in gestation length among rhesus macaques. the data were obtained from the timed-mating breeding program at the California Regional Primate Research Center (CRPRC). Information about approximately 700 pregnancies that resulted in spontaneous vaginal deliveries of liveborn young is presented. The average length of these pregnancies was 166.5 days. In this population, older females with higher parities had significantly longer pregnancies and significantly heavier infants than other females did. Other factors, including infant sex, month of conception, maternal reproductive history, and paternal identity, had no consistent effect upon gestation length.     

Paternity exclusion in six captive groups of rhesus monkeys (Macaca mulatta)

Five genetic markers were employed to attempt to identify the fathers of 135 Macaca mulatta offspring living in large outdoor field cages. Family studies of two of these markers to confirm mode of inheritance of phenotypes had not heretofore been reported. Of the 284 exclusions required to identify the fathers of all 135 monkeys, 198 (or 70 percent) were possible using only these five genetic polymorphisms. For 58 (or 43 percent) of these 135 offspring the father was identified. These data were applied to estimate the association between dominance rank of fathers and reproductive success. Fertility of first- and second-ranking fathers was judged to be about twice as high as that of third- and fourth-ranking fathers.     

The albumin polymorphism and bilirubin binding in rhesus monkeys (Macaca mulatta)

Family studies confirmed a codominant mode of inheritance of albumin phenotypes identified in Macaca mulatta. Preliminary epidemiological and bilirubin binding studies suggest that selection favors the variant allele by reducing risks of hyperbilirubinemia and might be responsible for this otherwise rare polymorphism.     

Segregation distortion and differential fitness at the albumin locus in rhesus monkeys (Macaca mulatta)

The observed patterns of segregation of two co-dominant alleles at the macaque albumin locus in 400 rhesus monkey offspring were compared with those expected for five segregating mating phenotypes. Rates of reproductive loss and conception were also compared among females of each albumin phenotype. The common albumin allele in macaques, Al^A_mac, segregated more frequently than expected when the mother was heterozygous but less frequently than expected when she was homozygous for Al^B_mac. In both cases, the phenotype identical to that of the mother appeared to be favored. Mothers who were either homozygous for Al^A_mac or heterozygous were also found to experience higher conception rates than mothers homozygous for Al^B_mac. It is hypothesized that phenotypic differences in bilirubin binding, and in competitive binding by dietary constituents, by albumin influences both these results and the nonrandom distribution of Al^B_mac in Asian macaques.     

Decrease in sexual initiative and responsiveness in female rhesus macaques (Macaca mulatta) during pregnancy

Although the sexual behavior of female rhesus macaques (Macaca mulatta) has been reported to decrease during pregnancy, systematic studies have been largely confined to reports of male behavior. Therefore, we designed a study to examine changes in female sexual behavior during pregnancy. Six cycling multiparous female rhesus macaques were paired during the periovulatory period of the menstrual cycle and during the first and second halves of pregnancy with six sexually experienced males of the same species. Each female was paired with the same male in all tests. The means of the behavioral measures scored on days 11–13 of the menstrual cycle, 35–56 of pregnancy, and 147–168 of pregnancy were compared. Females showed a significant decrease in the present contact ratio and the rate of threat-aways during pregnancy. Males showed lower rates of threatening-away, contacting, mounting, intromitting, and ejaculating when females were pregnant. The extent to which the decrease in male sexual behavior can be accounted for by an increase in female rejection is uncertain, but it is probably as significant as any loss of attractiveness that might accompany pregnancy.     

Fetal gender determination in early first trimester pregnancies of rhesus monkeys (Macaca mulatta) by fluorescent PCR analysis of maternal serum

Non-human primate fetal gender determination can be a powerful tool for research study design and colony management purposes. The recent discovery of the presence of fetal DNA in maternal serum has offered a new non-invasive approach for identification of fetal gender. We present a rapid and simple method for the sexing of developing rhesus monkeys in the first trimester by polymerase chain reaction (PCR) analysis of maternal serum. Serum samples were obtained from 72 gravid rhesus monkeys during 20-32 days of gestation (term 165 +/- 10 days). Fetal gender and the quantity of circulating fetal DNA were determined by real-time PCR analysis of the rhesus Y-chromosomal DNA sequences. The sensitivity for identifying a male fetus was 100% by 30 days gestation, and no false-positive results were observed. This study demonstrates that fetal gender can be reliably determined in the early first trimester from maternal serum samples, a non-invasive method for routine gender screening.     

Study of three non‐syndromic cases of congenital thumb aplasia in captive rhesus monkeys

Although congenital thumb absence has been reported frequently in humans, their occurrence in macaques is rare. We observed three cases of spontaneous thumb defects in captive female rhesus monkeys. One animal exhibited bilateral absence and two other presented unilateral thumb absence, all with metacarpal integrity. This report presents the clinical, radiological, and genealogical details as well as possible etiologies in an attempt to draw a parallel with humans and other primate species.     

Confirmatory factor analysis of personality structure in adult male rhesus monkeys (Macaca mulatta)

Reports from different laboratories have suggested that nonhuman primates have somewhat similar dimensions of personality. To date, however, no attempts have been made to statistically replicate a specific factor structure. In the present report, two independent observers recorded the behavior of 58 adult male rhesus monkeys, and then rated the animals with the use of a 50-item personality instrument. A confirmatory factor analysis (CFA) of the ratings resulted in the replication of a previously described four-factor personality structure [Maninger et al., American Journal of Primatology 61:73-83, 2003]. The first two dimensions-Sociability and Confidence-showed strong loadings and are similar to Affiliation and Agency dimensions in humans. The remaining dimensions-Equability and Irritability-were less clear, and it is possible that additional traits will have to be identified before a more robust structure can be established for these dimensions.     

Generation of monoclonal antibodies to Macaca mulatta (rhesus) IgA

One IgG1 and five IgM murine monoclonal antibodies (mAb) specific for rhesus (Rh) IgA were generated. These mAbs bound to Rh IgA but not IgG or IgM when tested by enzyme-linked immunosorbent assay. Immunoblotting revealed that the mAbs reacted with the alpha heavy chain of Rh but not human IgA. The IgG1 anti-Rh IgA mAb detected IgA-producing cells in sections of monkey gut examined by immunofluorescent staining. These mAbs should be useful for characterizing IgA responses in the Rh monkey.     

The hemogram,serum biochemistry,and electrolyte profile of the free-ranging Cayo Santiago rhesus macaques (Macaca mulatta)

Sixty-four male and 33 female free-ranging rhesus monkeys (Macaca mulatta) from one of six social groups on the island of Cayo Santiago, Puerto Rico, were surveyed to establish normal values for the hemogram and serum biochemical and electrolytes for the colony. Mean values (± 1 SD) are reported by sex for each of three age groups (2–3, 4–9 and ≥ 10 years). All adult females (≥ 4 years) were pregnant. There were significant differences for a number of variables compared to the range reported in the existing literature, and among the age and sex groups in the sampled population.     

Sexual preferences during artificial menstrual cycles in social groups of rhesus monkeys (Macaca mulatta)

Eight groups of rhesus monkeys each consisting of one male and four ovariectomized females were observed while two of the females were treated with hormones to produce artificial menstrual cycles. These were either synchronized or offset by 7-day increments. Sexually preferred females, defined by the numbers of ejaculations per test, received almost twice as many ejaculations as did non-preferred females during all synchronized and offset cycles and during all cycle phases. However, short-term changes in partner preference occurred when the midcycle phase of non-preferred females coincided with the middle or late progesterone phase of preferred females, suggesting a negative effect of progesterone on behavior during the menstrual cycle. There were highly significant differences between preferred and non-preferred partners for almost all of their sexual and social interactions, and preferred partners showed longer proximity and grooming times as well as higher levels of sexual activity. Partner preferences accounted for more of the behavioral variance between pairs than did female dominance, although males sought the proximity of dominant females independently of their partner preferences. Thus, in a setting uncomplicated by male mate competition, sexual preference by male rhesus monkeys is a robust phenomenon depending on complex interactions between dominance, hormonal status, and the individual behavior of female partners.     

Mandibular growth in the rhesus monkey (Macaca mulatta)

Mandibular growth of 42 rhesus monkeys (Macaca mulatta) was analyzed quantitatively and qualitatively. Four groups of animals were defined according to dentitional age (i.e., infant, juvenile, adolescent, young adult). At each age growth was observed for a 24 week period. Since some animals were observed at more than one stage of development, 57 periods of growth were studied. The growth incremental data were collected by superimposing serial cephalograms on mandibular implants. Growth and remodeling of both the skeletal and dento-alveolar components of the rhesus mandible were greatest in the infant monkeys and were less in successive age groups. Posterior relocation of the ramus was noted in all age groups while bone deposition on the anterior and inferior borders of the mandibular body was greatest in the younger animals. The most pronounced dental changes also occurred in the younger animals while the dentitions of the adolescent and adult animals were generally more stable. This study demonstrates that the rate and direction of normal mandibular growth varies with the age of the animal. Furthermore, mandibular growth is quantified at four defined maturational levels to provide a set of values illustrating normal mandibular growth. These values can also be used as control data for experimental studies.