Spontaneous hypertension and its sequelae in woolly monkeys (Lagothrix lagotricha)

Arteriolar nephrosclerosis was observed at necropsy in 26 of 38 woolly monkeys (Lagothrix lagotricha). This lesion is the earliest histologic change associated with hypertension in humans. Seventeen of the monkeys had died of congestive heart failure, renal failure or acute cardiovascular accident, complications similar to those seen in human hypertension. All monkeys known to be over 4 years of age were affected. Direct blood pressure measurements in nine otherwise healthy woolly monkeys revealed systolic pressures of 194 +/- 20 mmHg. Our physiologic, clinical and pathologic studies suggest that woolly monkeys develop hypertension spontaneously and could be a useful model for the study of human hypertension.     

Traditions in monkeys

Traditions, defined as relatively long‐lasting behavioral practices shared among members of a group partly via social learning, were studied in monkeys, specifically Japanese macaques, before being studied in great apes. Although apes and humans may share some social learning capacities that are absent in monkeys, a complete understanding of the roots of human culture requires attention to the socioecological conditions favoring traditions, however generated, in animals generally and in multiple behavioral domains. Using the four criteria of intergroup variation, observation of the origin and spread of a novel behavior, dissemination patterned according to age or kinship, or individuals' close observation of others' performance of the behavior before engaging in it, over twenty‐five behaviors have been nominated as traditions in free‐ranging monkey populations. Tolerant gregariousness has been proposed to increase the likelihood of the emergence of traditions in any behavioral domain. Omnivory and extractive foraging should favor the emergence of foraging‐related traditions; strong cooperative relationships and flexible coalitionary structure should favor the emergence of social conventions that function to test social bonds. These conditions are taxonomically widespread. Thus, the current restriction of most reported free‐ranging monkey traditions to two taxa (Macaca fuscata and Cebus) is likely to reflect variation in primatologists' research goals, methods, and concepts rather than real interspecific variation in the propensity to generate traditions.     

Stress in Yucatan spider monkeys: effects of environmental conditions on fecal cortisol levels in wild and captive populations

In the Yucatán Peninsula, spider monkeys Ateles geoffroyi yucatanensis are generally found in two contrasting conditions: large tracts of conserved forest or small fragments surrounded by human populations. In the present study, we analyzed fecal cortisol levels of spider monkeys to investigate whether environmental conditions have an influence on stress; specifically, we compared fecal cortisol across individuals living in conserved forests, fragmented forests and captive conditions (zoos and pets). Radioimmunoanalysis of fecal samples from 121 individuals indicated significant differences in mean cortisol for A. g. yucatanensis based on habitat type, with the lowest levels found in the conserved forest condition. The higher cortisol levels in both fragmented forest populations and in captive individuals may be the result of metabolic and behavioral stress. The mean male fecal cortisol concentration was significantly higher than that of females, and the fecal cortisol concentration was higher in the dry season compared with the wet season in a conserved habitat. Therefore, we emphasize the importance of considering sex and seasonality when monitoring fecal cortisol concentrations of spider monkeys, and more generally of frugivores, as they face a seasonal variation in food availability. Finally, our results suggest that forest fragmentation may create long-term stressors for spider monkeys, affecting the viability of populations living under such conditions.     

Stress Doppler echocardiography for early detection of systemic sclerosis-associated pulmonary arterial hypertension

IntroductionIn patients with systemic sclerosis (SSc), associated pulmonary arterial hypertension (SSc-APAH) is the leading cause of death. The objective of this prospective screening study was to analyse sensitivity and specificity of stress Doppler echocardiography (SDE) in detecting pulmonary hypertension (PH).MethodsPulmonary artery pressures and further parameters of PH were assessed by echocardiography and right heart catheterisation (RHC) at rest and during exercise in patients with SSc. Investigators of RHC were blinded to the results of non-invasive measurements.ResultsOf 76 patients with SSc (64 were female and mean age was 58±14 years), 22 (29 %) had manifest PH confirmed by RHC: four had concomitant left heart diseases, three had lung diseases, and 15 had SSc-APAH. Echocardiography at rest missed PH diagnosis in five of 22 patients with PH when a cutoff value for systolic pulmonary arterial pressure (PASP) was more than 40 mm Hg at rest. The sensitivity of echocardiography at rest was 72.7 % (95 % confidence interval (CI) 0.52–0.88), and specificity was 88.2 % (95 % CI 0.78–0.95). When a cutoff value for PASP was more than 45 mm Hg during low-dose exercise, SDE missed PH diagnosis in one of the 22 patients with PH and improved sensitivity to 95.2 % (95 % CI 0.81–1.0) but reduced specificity to 84.9 % (95 % CI 0.74–0.93). Reduction of specificity was partly due to concomitant left heart disease.ConclusionsThe results of this prospective cross-sectional study using RHC as gold standard in all patients showed that SDE markedly improved sensitivity in detecting manifest PH to 95.2 % compared with 72.7 % using echocardiography at rest only. Thus, for PH screening in patients with SSc, echocardiography should be performed at rest and during exercise.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01387035","term_id":"NCT01387035"}}NCT01387035. Registered 29 June 2011.     

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.     

Growth in Howler monkeys

Howler monkeys (Alouatta caraya) were studied in northern Argentina and subjected to complete post-mortem examination in connection with field observations of atherosclerosis. In order to estimate age of the animals, data was obtained on gross body dimensions, dental age, and organ weights in 298 animals covering the range of about 1–10 kg. The animals were divided into four size groups, and into male, non-pregnant and pregnant female categories. Statistical parameters were obtained for relative organ weights, organ allometry coefficients, gross body lengths, a body length formula based on the Ponderal Index and dental age. The parameters from howlers were compared with those for rhesus monkeys, chimpanzees, human and general primate organ allometric formulas, and differences due to sex and pregnancy reviewed. It is concluded that the growth pattern in howlers is rather similar to that reported for other primates, which makes it possible to estimate maturity satisfactorily, but that further methods must be developed for post-maturity dating.Publication No. 190 of the Oregon Regional Primate Research Center, Beaverton, Oregon, supported in part by Grants FR 00163 and GM 13605 of the National Institutes of Health.     

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.     

Horseshoe kidneys in vervet monkeys

Two cases of horseshoe kidneys in vervet monkeys are described. Apart from the fusion, the rest of the urogenital system was anatomically normal and renal function was apparently not affected by this condition. The microanatomy was normal in both cases.     

Drinking competition in vervet monkeys

During a period of water shortage, adult female and adult male vervet monkeys (Cercopithecus aethiops) obtained water by different methods. Females drank from tree-holes within their normal home range, while males invaded the territories of neighbouring groups. Higher-ranking females had access to preferred tree-holes. The mortality rate was high in both sexes and was greater in low-ranking than in high-ranking animals.