Entamoeba species infect humans and non-human primates, raising concerns associated with potential zoonotic transmission. Therefore, the prevalence of human Entamoeba infections is crucial for its management in areas, where macaques exhibit high infection rates. Previously, we demonstrated prevalent E. nuttalli infections in rhesus macaques in Kathmandu, Nepal. In this study, we surveyed Entamoeba infection among 185 schoolchildren from two schools visited by wild rhesus macaques to assess the risk of transmission. PCR-based screening for Entamoeba species identified E. coli in 13 % and E. dispar in 0.5 % of the human stool samples. However, E. nuttalli and E. chattoni infections, prevalent in macaques, were not detected in human samples. This suggests that Entamoeba spp. are not transmitted through macaques in the school environment. We surveyed the rhesus macaques living in the temple near schools as well as the rhesus and Assam macaques inhabiting Shivapri Nagarjun National Park, Kathmandu. Among the 49 macaque stool samples, E. chattoni, E. coli, E. nuttalli, and E. dispar were detected in 92 %, 86 %, 41 %, and 18 % of the samples, respectively. Notably, E. dispar infections in macaques were mostly prevalent in the temple. A sample isolated from Nagarujun showed an identical genotype at two tRNA-linked short tandem repeat loci to that of E. dispar isolated from humans, suggesting potential transmission from humans to macaques. Genotypic analysis of cultured E. nuttalli strains obtained from the macaques colonizing three locations demonstrated that the geographical distance rather than differences in macaque species played a crucial role in the genetic diversity of the parasites. The phylogenetic tree of E. nuttalli strains, including the previously isolated strains, reflected the geographical distribution of the isolation sites. This study sheds light on the intricate dynamics of Entamoeba transmission and genetic diversity in macaques and humans.

Single-unit (SU) activity-action potentials isolated from one neuron-has traditionally been employed to relate neuronal activity to behavior. However, recent investigations have shown that multiunit (MU) activity-ensemble neural activity recorded within the vicinity of one microelectrode-may also contain accurate estimations of task-related neural population dynamics. Here, using an established model-fitting approach, we compared the spatial codes of SU response fields with corresponding MU response fields recorded from the frontal eye fields (FEFs) in head-unrestrained monkeys (Macaca mulatta) during a memory-guided saccade task. Overall, both SU and MU populations showed a simple visuomotor transformation: the visual response coded target-in-eye coordinates, transitioning progressively during the delay toward a future gaze-in-eye code in the saccade motor response. However, the SU population showed additional secondary codes, including a predictive gaze code in the visual response and retention of a target code in the motor response. Further, when SUs were separated into regular/fast spiking neurons, these cell types showed different spatial code progressions during the late delay period, only converging toward gaze coding during the final saccade motor response. Finally, reconstructing MU populations (by summing SU data within the same sites) failed to replicate either the SU or MU pattern. These results confirm the theoretical and practical potential of MU activity recordings as a biomarker for fundamental sensorimotor transformations (e.g., target-to-gaze coding in the oculomotor system), while also highlighting the importance of SU activity for coding more subtle (e.g., predictive/memory) aspects of sensorimotor behavior.

Social living affords primates (including humans) many benefits. Communication has been proposed to be the key mechanism used to bond social connections, which could explain why primates have evolved such expressive faces. We assessed whether the facial expressivity of the dominant male (quantified from the coding of anatomically based facial movement) was related to social network properties (based on social proximity and grooming) in nine groups of captive rhesus macaques (Macaca mulatta) housed in uniform physical and social environments. More facially expressive dominant male macaques were more socially connected and had more cohesive social groups. These findings show that inter-individual differences in facial expressivity are related to differential social outcomes at both an individual and group level. More expressive individuals occupy more beneficial social positions, which could help explain the selection for complex facial communication in primates.

Allogrooming is a widespread, pervasive activity among non-human primates. Besides its hygienic function, it is thought to be instrumental in maintaining social bonds and establishing hierarchical structures within groups. However, the question arises as to whether the physiological and social benefits derived from social touch stem directly from body stimulation, or whether other mechanisms come into play. We address this question by analyzing an elaborate social behavior that we observed in two adult male macaques. This behavior demonstrates the existence of a persistent motivation to interact through a form of simulated grooming, as the animals were housed in adjacent enclosures separated by a glass panel preventing direct tactile contact. We find that such virtual grooming produces similar physiological sensations and social effects as allogrooming. We suggest that this behavior engages affective and reward brain circuits to the same extent as real social touch, and that this is probably achieved through high level processes similar to those involved in bodily illusions or synaesthetic phenomena previously described in humans. This observation reveals the unsuspected capacity of non-human primates to invent alternative, quasi-symbolic strategies to obtain effects similar to those provided by direct bodily interaction, which are so important for maintaining social bonds.

In this brief review, we discuss our efforts to validate nanoplatforms for imaging and treatment of endometriosis. We specifically highlight our use of nonhuman primates and primate tissues in this effort. Endometriosis is a painful disorder of women and nonhuman primates where endometrium-like tissue exists outside of the uterus. There are no reliable, specific, and noninvasive diagnostic tests for endometriosis. Laparoscopic imaging remains the gold standard for identifying small endometriotic lesions in both women and monkeys. Visualizing and surgically removing microscopic lesions remains a clinical challenge. To address this challenge, we have created nanoparticle reagents that, when administered intravenously, enter endometriotic lesions both passively and by targeting endometriotic cells. The particles can carry payloads, including near-infrared fluorescent dyes and magnetic nanoparticles. These agents can be used for imaging and thermal ablation of diseased tissues. We evaluated this approach on macaque endometriotic cells, human and macaque endometrium engrafted into immunodeficient mice, in endometrium subcutaneously autografted in macaques, and in rhesus monkeys with spontaneous endometriosis. Employing these models, we report that nanoplatform-based reagents can improve imaging and provide thermal ablation of endometriotic tissues.

The error-related negativity and an N2-component recorded over medial frontal cortex index core functions of cognitive control. While they are known to originate from agranular frontal areas, the underlying microcircuit mechanisms remain elusive. Most insights about microcircuit function have been derived from variations of the so-called canonical microcircuit model. These microcircuit architectures are based extensively on studies from granular sensory cortical areas in monkeys, cats, and rodents. However, evidence has shown striking cytoarchitectonic differences across species and differences in the functional relationships across cortical layers in agranular compared to granular sensory areas. In this minireview, we outline a tentative microcircuit model underlying cognitive control in the agranular frontal cortex of primates. The model incorporates the main GABAergic interneuron subclasses with specific laminar arrangements and target regions on pyramidal cells. We emphasize the role of layer 5 pyramidal cells in error and conflict detection. We offer several specific questions necessary for creating a specific intrinsic microcircuit model of the agranular frontal cortex.

Telomeres are specialized terminal sections of chromosomes that ensure the stability of the latter. DNA duplication during cell division is associated with telomere shortening due to the phenomenon of terminal underreplication. As cells divide, shortening of telomere length is considered to be one of the most important causes of cell aging. Estimation of telomere length still remains the subject of scientific research in gerontology and it is not used in clinical practice. Most often, rodents are used as a model object for studying the aging process, but the neuroendocrine mechanisms that influence, among other things, the regulation of the aging process differ in rodents and humans. The model objects closest in phylogenetic relation to humans are monkeys. In particular, Rhesus macaques is one of the representatives of the Old World most often used in biomedical research. However, data on age-related changes in telomere length in monkeys are extremely scarce. We studied the absolute average length of telomeres in DNA from blood leukocytes of 29 clinically healthy male rhesus monkeys aged from 4 to 24 years using quantitative PCR-method. The data obtained did not correspond to the normal distribution and the correlation analysis showed the absence of a significant dependence of telomere length on the age of the animals (rs=0,27; p>0,05). Thus, our study does not confirm the dependence of changes in the average length of telomeres of blood leukocytes with age.
Теломеры представляют собой специализированные концевые участки хромосом, обеспечивающие стабильность последних. Удвоение ДНК при делении клетки связано с укорочением теломер вследствие феномена концевой недорепликации. По мере деления клеток укорочение длины теломер считается одной из важнейших причин старения клетки. Оценка длины теломер до настоящего времени остается предметом научных исследований в области геронтологии и не применяется в клинической практике. Чаще всего в качестве модельного объекта изучения процессов старения используют грызунов, однако нейроэндокринные механизмы, влияющие в том числе на регуляцию процесса старения, отличаются у грызунов и человека. Наиболее близким в филогенетическом отношении к человеку модельным объектом являются обезьяны, в частности макаки резусы — один из чаще всего используемых в биомедицинских исследованиях представителей Старого Света. Однако данные об изменении длины теломер у низших обезьян с возрастом крайне немногочисленны. Мы изучили абсолютную среднюю длину теломер ДНК лейкоцитов крови у 29 клинически здоровых самцов макак резусов 4–24 лет методом количественной ПЦР. Полученные данные не соответствовали нормальному характеру распределения, а корреляционный анализ показал отсутствие значимой зависимости длины теломер от возраста животных (rs=0,27, p>0,05). Таким образом, наше исследование не подтверждает зависимость изменения средней длины теломер лейкоцитов крови с возрастом.

Bee stings (BS) are a life-threatening issue and a growing concern for public health and animals in the Americas. We describe the clinical, pathological, and ultrastructural findings of a massive lethal bee attack in two non-human primates (NHPs). Both animals showed BS scattered throughout the skin, surrounded by a local reaction, diffuse pulmonary congestion, edema, hemorrhage, and remarkable degeneration and necrosis of renal epithelial cells from the proximal and distal tubules, characterizing a systemic bee envenomation reaction.

Olfaction is one of the evolutionarily oldest senses and plays a fundamental role in foraging and social interactions across mammals. In primates, the role of olfaction is now well recognized, but better investigated in strepsirrhine and platyrrhine primates than in catarrhines. We observed the sniffing behavior of semi-free ranging Barbary macaques, Macaca sylvanus, at Affenberg Salem, Germany, to assess how frequently macaques sniff and in which contexts, and how sniffing is affected by sex and age. Focal observations of 24 males and 24 females aged 1-25 years showed that Barbary macaques sniffed, on average, 5.24 times per hour, with more than 80% of sniffs directed at food. Irrespective of the context, younger individuals sniffed more often than older ones. Females\' sniffs were more often directed at food than male sniffs, while males sniffed more often than females in a social context. Sniffs at conspecifics occurred primarily in a sexual context, with 70% of social sniffs directed at female anogenital swellings performed by males. Of the observed 176 anogenital inspections, 51 involved sniffing of the swelling. Olfactory inspections were followed by copulation significantly less often than merely visual inspections, suggesting that anogenital odors may play a role in male mating decisions, but the role of olfaction in sexual interactions warrants further investigations. In sum, results show that Barbary macaques routinely use olfaction during feeding, but also in a socio-sexual context, corroborating the relevance of the olfactory sense in the lives of catarrhine primates.

UNASSIGNED: Functional magnetic resonance imaging (fMRI) visualizes hemodynamic responses associated with brain and spinal cord activation. Various types of pain have been objectively assessed using fMRI as considerable brain activations. This study aimed to develop a pain model in cynomolgus macaques undergoing knee surgery and confirm brain activation due to resting pain after knee surgery.
UNASSIGNED: An osteochondral graft surgery on the femoral condyle in the unilateral knee was performed on four cynomolgus macaques (Macaca fascicularis). Resting pain was evaluated as changes in brain fMRI findings with a 3.0-T MRI scanner preoperatively, postoperatively, and after postoperative administration of morphine. In the fMRI analysis, Z-values >1.96 were considered statistically significant.
UNASSIGNED: Brain activation without stimulation after surgery in the cingulate cortex (3.09) and insular cortex (3.06) on the opposite side of the surgery was significantly greater than that before surgery (1.05 and 1.03, respectively) according to fMRI. After the administration of morphine, activation due to resting pain decreased in the cingulate cortex (1.38) and insular cortex (1.21).
UNASSIGNED: Osteochondral graft surgery on the femoral condyle can lead to postoperative resting pain. fMRI can reveal activation in pain-related brain areas and evaluate resting pain due to knee surgery.