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Compositional changes in the tracheal and bronchial cartilages can affect respiratory ventilation and lung function. We aimed to elucidate element accumulation in the tracheal and bronchial cartilages of monkeys and divided it into four sites: the tracheal, tracheal bifurcation, left bronchial, and right bronchial cartilages. The elemental content was analyzed using inductively coupled plasma atomic emission spectrometry. The average calcium content was two to three times higher in the tracheal cartilage than in the other three cartilages. The trends of phosphorus and zinc were similar to those of calcium. The average calcium, phosphorus, and zinc cartilage contents were the highest in the tracheal cartilage and decreased in the following order: the left bronchial, right bronchial, and tracheal bifurcation cartilages. These findings revealed that differences existed in element accumulation between different sites within the same airway cartilage and that calcium, phosphorus, and zinc accumulation mainly occurred in the tracheal cartilage. A substantial direct correlation was observed between age and calcium content in the tracheal and bronchial cartilages and all such monkeys with high calcium content were > four years of age. These results suggest that calcium accumulation occurs in the tracheal and bronchial cartilages after reaching a certain age. An extremely substantial direct correlation was observed between calcium and phosphorus contents in the tracheal and bronchial cartilages. This finding is similar to the previously published calcium and phosphorus correlations in several other cartilages, suggesting that the calcium and phosphorus contents of cartilage exist in a certain ratio.

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To survive in nature, it is crucial for animals to promptly and appropriately respond to visual information, specifically to animacy cues that pose a threat. The subcortical visual pathway is thought to be implicated in the processing of visual information necessary for these responses. In primates, this pathway consists of retina-superior colliculus-pulvinar-amygdala, functioning as a visual pathway that bypasses the geniculo-striate system (retina-lateral geniculate nucleus-primary visual cortex). In this mini review, we summarize recent neurophysiological studies that have revealed neural responses to threatening animacy cues, namely snake images, in different parts of the subcortical visual pathway and closely related brain regions in primates. The results of these studies provide new insights on (1) the role of the subcortical visual pathway in innate cognitive mechanisms for predator recognition that are evolutionarily conserved, and (2) the possible role of the medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC) in the development of fear conditioning to cues that should be instinctively avoided based on signals from the subcortical visual pathway, as well as their function in excessive aversive responses to animacy cues observed in conditions such as ophidiophobia (snake phobia).

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Trophoblast stem cells (TSCs), derived from the trophectoderm of the blastocyst, are used as an in vitro model to reveal the mechanisms underlying placentation in mammals. In humans, suitable culture conditions for TSC derivation have recently been established. The established human TSCs (hTSCs) differentiate efficiently toward two trophoblast subtypes: syncytiotrophoblasts (STBs) and extravillous trophoblasts (EVTs). However, the efficiency of differentiation is lower in macaque TSCs than in hTSCs. Here, we demonstrate that the activation of Wnt signaling downregulated the expression of inhibitory G protein and induced trophoblastic lineage switching to the STB progenitor state. The treatment of macaque TSCs with a GSK-3 inhibitor, CHIR99021, upregulated STB progenitor markers and enhanced proliferation. Under the Wnt signaling-activated conditions, macaque TSCs effectively differentiated to STBs upon dbcAMP and forskolin treatment. RNA-seq analyses revealed the downregulation of inhibitory G protein, which may make macaque TSCs responsive to forskolin. Interestingly, this lineage switching appeared to be reversible as the macaque TSCs lost responsiveness to forskolin upon the removal of CHIR99021. The ability to regulate the direction of macaque TSC differentiation would be advantageous in elucidating the mechanisms underlying placentation in non-human primates.

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In humans, cognitive aging is highly variable, with some individuals experiencing decline while others remain stable, and different cognitive domains exhibiting uneven vulnerability to aging. The neural mechanisms driving this intra- and inter-individual variability are not fully understood, making longitudinal studies in translational models essential for elucidating the timelines and processes involved. The common marmoset (Callithrix jacchus), a short-lived nonhuman primate, offers an unprecedented opportunity to conduct longitudinal investigations of aging and age-related disease over a condensed time frame, in a highly translatable animal model. The potential of the marmoset as a model for cognitive aging is indisputable, but a comprehensive cognitive battery tailored for longitudinal aging studies has not yet been developed, applied, or validated. This represents a critical missing piece for evaluating the marmoset as a model and understanding the extent to which marmoset cognitive aging mirrors the patterns found in humans, including whether marmosets have individual variability in their vulnerability to age-related cognitive decline. To address this, we developed a comprehensive touchscreen-based neuropsychological test battery for marmosets (MarmoCog), targeting five cognitive domains: working memory, stimulus-reward association learning, cognitive flexibility, motor speed, and motivation. We tested a large cohort of marmosets, ranging from young adults to geriatrics, over several years. We found significant variability in cognitive aging, with the greatest decline occurring in domains dependent on the prefrontal cortex and hippocampus. Additionally, we observed significant inter-individual variability in vulnerability to age-related cognitive decline: some marmosets declined across multiple domains, others in just one, and some showed no decline at all. This pattern mirrors human cognitive aging, solidifies the marmoset as an advantageous model for age-related cognitive decline, and provides a strong foundation for identifying the neural mechanisms involved.

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A captive 17-year-old male cynomolgus monkey (Macaca fascicularis) developed diffuse large B-cell lymphoma (DLBCL). This was the first report of DLBCL presenting with a mandible mass and violation of the paranasal sinus in a cynomolgus monkey. The neoplasm showed marked microscopical malignant aspects. Immunohistochemical staining showed strong positive expression of CD20. These features may contribute to the diagnosis and therapeutics of DLBCL in NHPs.

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Introduction: Today, high-voltage (HV) lines create a pernicious environment for humans living or working in the vicinity and even under these lines. The male rhesus monkey is used to investigate the effects of fields produced by HV towers. This study examines the function and level of impact in rhesus monkeys' brains from the cerebellum's cognitive, biological, and structural perspective. Methods: Two monkeys have been used, one as a control and the second as a test. The monkey under test was subjected to a simulated HV electrical field of 3 kV/m, 4 hours a day, for 1 month. Behavioral tests were performed using a device designed and built for this purpose. Concentration analysis of adrenocorticotropic hormones (ACTH) and inspection of glucocorticoid receptor gene's (GR) expression were performed by the reverse transcription polymerase chain reaction method. Changes in cerebellar anatomy were examined with magnetic resonance imaging (MRI). All tests were performed before and after the study period and compared with the control monkey. Results: Cognitive tests showed a significant reduction for the monkey exposed to the HV electrical field in the first week after imposition compared with the same time before. Also, the expression of the GR gene decreased, and the concentration of ACTH hormone in plasma increased. Surveying the level of cerebral MRI images did not show any difference, but hemorrhage was evident in a part of the cerebellum. Conclusion: The tested monkey's cognitive, biological, and MRI results showed a decrease in visual learning and memory indices.

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Natal dispersal is an important life-history stage influencing individual fitness, social dynamics of groups and population structure. Understanding factors influencing dispersal is essential for evaluating explanations for the evolution and maintenance of social organization, including parental care and mating systems. The social and mating systems of Azara's owl monkeys (Aotus azarae) are infrequent among mammals; these primates are pair-living, serially and genetically monogamous and both sexes directly care for offspring. To evaluate the role that competition and inbreeding avoidance play in shaping dispersal patterns, we used 25 years of demographic and genetic data to examine how variation in timing of natal dispersal is related to social (adult replacements, step-parents, births and group size) and ecological factors (seasonal abundance of resources) in a wild population of A. azarae in Formosa, Argentina. We found that all males and females dispersed from their natal groups, but subadults delayed dispersal when a step-parent of the opposite sex joined the group, indicating that they may perceive these step-parents as potential mates. Dispersal was more probable when resource conditions were better, regardless of age. Overall, agonistic conflict over food and potential mates with adults in the natal group, as well as inbreeding avoidance, contribute to regulating dispersal.

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With the development and widespread application of electromagnetic technology, the health hazards of electromagnetic radiation have attracted much attention and concern. The effect of electromagnetic radiation on the nervous system, especially on learning, memory, and cognitive functions, is an important research topic in the field of electromagnetic biological effects. Most previous studies were conducted with rodents, which are relatively mature. As research has progressed, studies using non-human primates as experimental subjects have been carried out. Compared to rodents, non-human primates such as macaques not only have brain structures more similar to those of humans but also exhibit learning and memory processes that are similar. In this paper, we present a behavioral test system for the real-time evaluation of the working memory (WM) of macaques in a microwave environment. The system consists of two parts: hardware and software. The hardware consists of four modules: the operation terminal, the control terminal, the optical signal transmission, and detection module and the reward feedback module. The software program can implement the feeding learning task, the button-pressing learning task, and the delayed match-to-sample task. The device is useful for the real-time evaluation of the WM of macaques in microwave environments, showing good electromagnetic compatibility, a simple and reliable structure, and easy operation.

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Clostridium perfringens is a leading cause of human gastroenteritis. The genome sequence of C. perfringens CP201 from an asymptomatic rhesus monkey, Macaca mulatta, consists of one chromosome (3,241,413 bp; 30.22% G + C) and one plasmid (92,983 bp; 28.43% G + C), encoding 2,935 genes, 94 tRNAs, 30 rRNAs, and 1 CRISPR array.

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Temporal discounting, in which the recipient of a reward perceives the value of that reward to decrease with delay in its receipt, is associated with impulsivity and psychiatric disorders such as depression. Here, we investigate the role of the serotonin 5-HT4 receptor (5-HT4R) in modulating temporal discounting in the macaque dorsal caudate nucleus (dCDh), the neurons of which have been shown to represent temporally discounted value. We first mapped the 5-HT4R distribution in macaque brains using positron emission tomography (PET) imaging and confirmed dense expression of 5-HT4R in the dCDh. We then examined the effects of a specific 5-HT4R antagonist infused into the dCDh. Blockade of 5-HT4R significantly increased error rates in a goal-directed delayed reward task, indicating an increase in the rate of temporal discounting. This increase was specific to the 5-HT4R blockade because saline controls showed no such effect. The results demonstrate that 5-HT4Rs in the dCDh are involved in reward-evaluation processes, particularly in the context of delay discounting, and suggest that serotonergic transmission via 5-HT4R may be a key component in the neural mechanisms underlying impulsive decisions, potentially contributing to depressive symptoms.

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The pharmacokinetics and tissue distribution of renadirsen sodium, a dystrophin exon-skipping phosphorothioate-modified antisense oligonucleotide with 2'-O,4'-C-ethylene-bridged nucleic acid (ENA), after subcutaneous or intravenous administration to cynomolgus monkeys were investigated. The plasma concentration of renadirsen after subcutaneous administration at 1, 3, and 10 mg/kg increased with the dose. The absolute bioavailability at 3 mg/kg after subcutaneous administration was calculated as 88.6%, and the time to reach maximum plasma concentration of renadirsen was within 4 h, indicating the efficient and rapid absorption following subcutaneous administration. The exposure of muscle tissues to renadirsen was found to increase with repeated dosing at 6 mg/kg, and higher exposure was observed in the diaphragm and heart than in the quadriceps femoris and anterior tibialis muscles. Renadirsen achieved more exon 45-skipped dystrophin mRNA in the diaphragm and heart than in the quadriceps femoris and anterior tibialis muscles. Renadirsen also showed a cumulative skipping effect in a repeated-dose study. The findings on exon 45-skipped dystrophin mRNA in these muscle tissues were consistent with the concentration of renadirsen in these tissues. Because it is not feasible to directly evaluate drug concentration and exon skipping in the heart and diaphragm in humans, the pharmacokinetics and pharmacodynamics of renadirsen in these tissues in monkeys are crucial for the design and interpretation of clinical settings.

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Recent research suggests that socio-ecological factors such as dietary specialization and social complexity may be drivers of advanced cognitive skills among primates. Therefore, we assessed the ability of 12 black-handed spider monkeys (Ateles geoffroyi), a highly frugivorous platyrrhine primate with strong fission-fusion dynamics, to succeed in a serial visual reversal learning task. Using a two-alternative choice paradigm we first trained the animals to reliably choose a rewarded visual stimulus over a non-rewarded one. Upon reaching a pre-set learning criterion we then switched the reward values of the two stimuli and assessed if and how quickly the animals learned to reverse their choices, again to a pre-set learning criterion. This stimulus reversal procedure was then continued for a total of 80 sessions of 10 trials each. We found that the spider monkeys quickly learned to reliably discriminate between two simultaneously presented visual stimuli, that they succeeded in a visual reversal learning task, and that they displayed an increase in learning speed across consecutive reversals, suggesting that they are capable of serial reversal learning-set formation with visual cues. The fastest-learning individual completed five reversals within the 80 sessions. The spider monkeys outperformed most other primate and nonprimate mammal species tested so far on this type of cognitive task, including chimpanzees, with regard to their learning speed in both the initial learning task and in the first reversal task, suggesting a high degree of behavioral flexibility and inhibitory control. Our findings support the notion that socio-ecological factors such as dietary specialization and social complexity foster advanced cognitive skills in primates.

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Sexual behavior in animals fulfills reproductive and social functions, extending beyond the traditional focus on reproduction. Same-sex sexual behavior, defined as genital contact or manipulation between individuals of the same sex, occurs in various primate species. In spider monkeys, grappling, a behavior involving prolonged mutual embraces, face greeting, tail intertwining, and genital manipulation, occurs primarily between males. Here, we report a novel incidence of same-sex sexual behavior and grappling between two subadult male brown-headed spider monkeys (Ateles fusciceps fusciceps). Our observation contributes to the understanding of the social functions of sexual behavior and to the broader appreciation of primate sexuality.

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Papillomaviruses (PVs) are double-stranded, circular, epitheliotropic DNA viruses causing benign warts (papillomas) or inducing dysplasia that can progress to cancer. Although they have been identified in all vertebrate taxa, most classified types are human PVs (HPVs); relatively little is known about PVs in other species. Here we characterize a novel Gammapapillomavirus type, PtepPV1, from a nasal swab of a wild red colobus (Piliocolobus tephrosceles) in Kibale National Park, Uganda. The virus has a genome of 6576 bases, encoding the seven canonical early (E) ORFs (E6, E7, E1, E2, E4, E1^E4 and E8^E2) and two late (L) ORFs (L1 and L2) of the gammapapillomaviruses, and is 81.0% similar to HPV-mSK_118, detected in a cutaneous wart from an immunocompromised human patient, in the L1 gene at the amino acid level. Alphapapillomaviruses (genus Alphapapillomavirus) cause anogenital carcinomas such as cervical cancer and have been described previously in several nonhuman primates. However, the first gammapapillomavirus (genus Gammapapillomavirus), which cause transient cutaneous infections, was not described until 2019 in a healthy rhesus macaque (Macaca mulatta) genital swab. The new virus from red colobus, PtepPV1, has many genomic features encoded by high-risk oncogenic PVs, such as the E7 gene LXSXE and CXXC motifs, suggesting potential for pRb and zinc-finger binding, respectively. To our knowledge, PtepPV1 is also the first reported nonhuman primate PV found in the nasal cavity. PtepPV1 expands the known host range, geographical distribution, tissue tropism and biological characteristics of nonhuman primate PVs.

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BACKGROUND AND OBJECTIVE: Viral respiratory infections stand as a considerable global health concern, presenting significant risks to the health of both humans and animals. This study aims to conduct a preliminary analysis of the time series of viral load in the nasal cavity-nasopharynx (NC-NP) of the human and rhesus macaque (RM). METHODS: Taking into account the random uniform distribution of virus-laden droplets with a diameter of 10 µm in the mucus layer, this study applies the computational fluid dynamics-host cell dynamics (CFD-HCD) method to 3D-shell NC-NP models of human and RM, analyzing the impact of initial distribution of droplets on the viral dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), estimating parameters in the HCD model based on experimental data, integrating them into simulations to predict the time series of viral load and cell counts, and being visualized. The reproductive number (R0) are calculated to determine the occurrence of infection. The study also considers cross-parameter combinations and cross-experimental datasets to explore potential correlations between the human and RM. RESULTS: The research findings indicate that the uniform distribution of virus-laden droplets throughout the whole NC-NP models of human and RM is reasonable for simulating and predicting viral dynamics. The visualization results offer dynamic insights into virus infection over a period of 20 days. Studies involving parameter and dataset exchanges between the two species underscore certain similarities in predicting virus infections between the human and RM. CONCLUSIONS: This study lays the groundwork for further exploration into the parallels and distinctions in respiratory virus dynamics between humans and RMs, thus aiding in making more informed decisions in research and experimentation.

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BACKGROUND: Marmosets, Callithrix spp, are small New World monkeys that have gained importance as an experimental animal model for human. Despite its use, information on its renal morphometry, vascularization, and location are limited. Therefore, this study will supply basic anatomy for applied studies and for comparative anatomy. METHODS: Fifty cadavers of Callithrix spp were collected on highways from the Atlantic Forest biome, identified and injected with a 10% formaldehyde solution. Later, the specimens were dissected and the measurements and topography of the kidneys and renal vessels were recorded. Both left and right kidneys were significantly larger in females. RESULTS: In the specimens studied, the average body length was 20.00 ± 2.46 cm in males and 20.50 ± 1.98 cm in females (p = .43). The kidneys of the Callithrix spp. were symmetrical in shape and resembled a "bean." They were also pale brown with a smooth surface. In males, the most frequent location of the right kidney was at the L1-L2 level (92%), while the location of the left kidney was between L2 and L3 (76%). In females, the most frequent location of the right kidney was at the L1-L2 level (56%), while the location of the left kidney was between L2 and L3 (32%) (Table 1). However, in seven (28%) males and nine (36%) females, the kidneys were at the same level. CONCLUSIONS: In both sexes, there was a positive and significant linear correlation between body length and kidney length. Regardless of the variable location of the kidneys in both sides and in either sexe, the right kidney was always located more cranially than the left, similar to observations in other non-human primates.

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BACKGROUND: Human-wildlife conflict (HWC) is any interaction between humans and wildlife that arises when wildlife necessities encroach on those of the human population. It affects all areas where animal and peoples cohabit regardless of geography or climatic circumstances; but the burden is great in developing nations. De Brazza's monkey (DM) (Cercopithecus neglectus) is one of the most unusual species in the group of Old-World monkeys commonly known as guenons. The De Brazza's monkey is distributed in different parts of African forests from Guinea to Ethiopia. This study was conducted in Kafa Biosphere Reserve, Kafa Zone, South West Ethiopia, to assess the causes of human wildlife conflict in the area. The methods used were, household questionnaire, focus group discussion and direct field observation from June 2022 to May 2023. RESULTS: The study revealed that the major causes of human De Brazza's monkey conflicts were; habitat destruction 52.9%, (n = 72), human proximity to natural forest, 25.7%, (n = 35) and increasing of its population size 8.1 %, (n = 11). These monkeys' raids crop usually early in the morning 42.6%, (n = 58), and late evening 29.4%, (n = 40). Maize was the most damaged crop by De Brazza's monkey followed by coffee. The study also confirmed that guarding was the most common method used to protect crops from crop raiding wildlife in the area. Majority 66.2%, (n= 90) of the informants had negative attitude but 22.1%, (n = 30) had positive attitude towards De Brazza's monkey conservation. CONCLUSION: The study discovered that, in contrast to olive baboons and grivet monkeys in the area, De Brazza's monkeys were not previously identified as crop raiders; however, they are currently causing damage to crops, especially maize and coffee crops. This could be due to habitat destruction and human proximity to the forest boundary. Thus, the conflict between humans and De Brazza's monkeys is escalating. As such, we recommended more research on the population status of the monkeys and strategies for coexist in the area.

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A thorough characterization of induced pluripotent stem cells (iPSCs) used with in vitro models or therapeutics is essential. Even iPSCs derived from a single donor can exhibit variability within and between cell lines, which can lead to heterogeneity in results and hinder the promising future of cell replacement therapies. In this study, the cell seeding density of human and rhesus monkey iPSCs was tested to maximize the cell line-specific yield of the generated cardiomyocytes. We found that, despite using the same iPSC generation and differentiation protocols, the cell seeding density for the cell line-specific best differentiation efficiency could differ by a factor of four for the four cell lines used here. In addition, the cell lines showed differences in the range of cell seeding densities that they could tolerate without the severe loss of differentiation efficiency. Overall, our data show that the cell seeding density is a critical parameter for the differentiation inefficiency of primate iPSCs to cardiomyocytes and that iPSCs generated with the same episomal approach still exhibit considerable heterogeneity. Therefore, individual characterization of iPSC lines is required, and functional comparability with in vivo processes must be ensured to warrant the translatability of in vitro research with iPSCs.

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