Serum electrophoretic patterns of karyotypically defined owl monkeys (Aotus trivirgatus).

Sera were electrophoretically separated and examined from 238 karyotyped Aotus trivirgatus and 29 unkaryotyped offspring. Albumin polymorphism was observed with high frequency and found to conform to a codominant allele mode of transmission. A unique alpha globulin was identified in Karyotypes I, VII and unkaryotyped offspring, of which one parent was a Karyotype I. This alpha globulin phenotype appears to be a dominant characteristic.     

Eosinophilic myelocytoma in an owl monkey (Aotus trivirgatus)

A mass found in the anterior mediastinum at necropsy of an adult female owl monkey (Aotus trivirgatus) was morphologically consistent with an eosinophilic myelocytoma. Lymph nodes, kidneys, bone marrow, and other tissues were diffusely infiltrated by neoplastic cells. Intracellular and extracellular Charcot-Leyden crystals were present in the neoplasm.     

Two new karyotypes in the Peruvian owl monkey (Aotus trivirgatus)

The observation of remarkable karyotypic variation in owl monkeys (Aotus trivirgatus) stimulated us to study the chromosomal evolution of this New World genus. As an extension of this project, we examined the chromosome complement of a “phenotype-B” Aotus population from Peru. In addition to karyotype V(2n = 46), two new karyotypes with diploid numbers of 47 and 48 were identified. A G-band comparison of these karyotypes indicated that the chromosome number polymorphism in these Peruvian owl monkeys resulted from a single fusion or fission event involving a single metacentric and two acrocentric chromosome pairs. This mechanism is also known to be responsible for the chromosome number polymorphism in at least two other populations of phenotype B Aotus, one from Colombia and the other from Panama.     

Breeding the owl monkey (Aotus trivirgatus) in a laboratory environment.

A breeding colony of owl monkeys (Aotus trivirgatus) established in 1972 produced 35 live infants during the first 3 years from an average daily population of 30 monogamous pairs. Initial productivity was poor, but once the breeding pairs were set up by karyotypes, reproductive performance improved. No seasonal influence on births was observed and most births occurred during daylight hours. Uterine size during gestation ranged from about 1 cm in diameter at 30 days after conception to 7--8 cm (transverse diameter) x 18--20 cm (longitudinal diameter) at 115 days after conception. The fetal head was palpable at 85 days. A gestation period of 120-140 days was estimated from extrapolation of uterine palpation data and interbirth intervals. Vaginal swabs collected from six females during two separate 1-month periods did not consistently reveal estrous cycles. An analysis of owl monkey milk showed it to contain 88.2% water, 2.16% crude protein, 2.09% fat, 7.52% lactose, and 0.36% ash.     

Cardiomyopathy in captive owl monkeys (Aotus nancymae)

Dilated cardiomyopathy (DCM) was identified histopathologically in a colony of owl monkeys (Aotus nancymae) over a 15-year period. We characterized the incidence of cardiac disease echocardiographically in the colony over a 14-month period. Of 77 monkeys, 21 had systolic myocardial failure, and postmortem examination confirmed the antemortem diagnosis of DCM in eight animals. Monkeys with a questionable diagnosis at the first examination demonstrated progression of disease with time. Left ventricular end-systolic cross-sectional area and left ventricular fractional area change were the indices that most reliably discriminated between normal and diseased animals. Serum cardiac troponin I concentrations were below detectable limits in normal and diseased monkeys. The apparent high prevalence of disease in this colony precluded establishment of reference intervals for Aotus nancymae. Our study provides the first comprehensive echocardiographic evaluation of owl monkeys with cardiomyopathy.     

Banded chromosomes of the owl monkey, Aotus trivirgatus.

Chromosomes of the owl monkey, Aotus trivirgatus, with 2n=54, 53, or 52, have been stained to show quinacrine (Q-) and Giemsa (G-) bands, and a karyotypic arrangement has been proposed based on lengths, centrometric index, and banding pattern. C-bands were present at the centromeric region of every chromosome and over the entire short arm of certain acrocentric chromosomes; 5-methylcytosine was concentrated in the same regions. Bright Q-bands at the telomeric ends of the short arms of some chromosomes probably represent a second type of repetitive DNA. Ag-staining showed that only the chromosomes bearing a secondary constriction are nucleolus organizer chromosomes.     

Karyotypic variation in susceptibility to hemolytic anemia and idiopathic eosinophilia of owl monkeys,Aotus trivirgatus

Hematologic data gathered over a period of 4.8 years from 196 owl monkeys,Aotus trivirgatus, were analyzed to find if karyotypic differences existed. It was found that none of 30 animals of karyotypes K-I and K-VI developed hemolytic anemia, whereas 46 of 99 animals of K-II, K-III and K-IV did (p<0.005). Analysis of hemograms of normal owl monkeys showed that mean percent eosinophils varied markedly, K-I monkeys having lowest counts, 3.2%, and K-VI animals having the highest, 33%. These results establish that idiopathic eosinophilia and hemolytic anemia in this species are probably unrelated but susceptibility to both has a strong genetic component.     

Visual capacities of the owl monkey (Aotus trivirgatus): temporal contrast sensitivity.

Aotus monkeys were tested in a forced-choice discrimination task to determine their ability to discriminate sinusoidally flickering lights varying in temporal frequency and luminance contrast. Under conditions of moderate light adaptation this primate is maximally sensitive to lights flickering at 10 Hz while the highest frequency they can discriminate is about 42 Hz. At very low light levels (10(-5) ft L) maximum sensitivity is for 2.2--5 Hz flicker. The highest flicker rate that could be discriminated under these conditons was about 29 Hz. In comparison to humans tested in the same situation. Aotus monkeys show relatively lower sensitivity to temporal flicker under conditions of light adaptation but relatively higher sensitivity at very low light levels.     

Mortality causes of owl monkeys (Aotus nancymae and Aotus vociferans) in captivity

To determine the main causes of death in "owl monkeys" (Aotus nancymae and A. vociferans) in captivity, 115 necropsies were performed. According to the macroscopic findings and clinical data, results are as follow: acute lobular pneumonia (25.2%), chronic nephropathy (10.4%), acute catarrhal enteritis (8.7%), acute hemorrhagic enteritis (7%), acute toxic hepatitis (5.2%), trauma (5.2%), and others.     

Pregnancy diagnosis in owl monkeys (Aotus trivirgatus): evaluation of the hemagglutination inhibition test for urinary chorionic gonadotropin.

The Subhuman Primate Pregnancy Test was evaluated as a means of detecting urinary chorionic gonadotropin to aid in pregnancy diagnosis in owl monkeys. Using radioimmunoassay, the excretion pattern of chorionic gonadotropin from pregnant owl monekys was delineated, the hormone being detected from 16 weeks prepartum until birth. By comparison, the pregnancy test kit detected chorionic gonadotropin between the fourteenth week prepartum and the last week of gestation with 94% accuracy. In a 2-year study using a simplified urine collection technique, the Subhuman Primate Pregnancy Test was shown to be a valuable procedure for diagnosing pregnancy and detecting spontaneous abortions in owl monkeys.     

Gestation and inter-birth intervals in the owl monkey (Aotus trivirgatus griseimembra).

A single, timed mating indicated a gestation period of 133 days for Aotus trivirgatus griseimembra. This figure is confirmed by approximate correspondence with minimum inter-birth intervals, results from radioimmunoassay of urinary oestrogens during pregnancy, and general agreement with a logarithmic plot of gestation period against body weight for simian primates. Birth data indicate that owl monkey females in present colonies in captivity breed throughout the year and will, on average, produce 3 infants every 2 years. There is no evidence of a characteristic post-partum oestrus.