Temporal changes in calcium-binding proteins in the medial geniculate nucleus of the monkey Sapajus apella

The subdivisions of the medial geniculate complex can be distinguished based on the immunostaining of calcium-binding proteins and by the properties of the neurons within each subdivision. The possibility of changes in neurochemistry in this and other central auditory areas are important aspects to understand the basis that contributing to functional variations determined by environmental cycles or the animal's cycles of activity and rest. This study investigated, for the first time, day/night differences in the amounts of parvalbumin-, calretinin- and calbindin-containing neurons in the thalamic auditory center of a non-human primate, Sapajus apella. The immunoreactivity of the PV-IR, CB-IR and CR-IR neurons demonstrated different distribution patterns among the subdivisions of the medial geniculate. Moreover, a high number of CB- and CR-IR neurons were found during day, whereas PV-IR was predominant at night. We conclude that in addition to the chemical heterogeneity of the medial geniculate nucleus with respect to the expression of calcium-binding proteins, expression also varied relative to periods of light and darkness, which may be important for a possible functional adaptation of central auditory areas to environmental changes and thus ensure the survival and development of several related functions.

Capuchin monkey tool use: Overview and implications

Nutcracking capuchins are mentioned in reports dating as far back as the sixteenth century,(1,2) as well as in Brazilian folklore.(3) However, it was barely a decade ago that primatologists ""discovered"" the spontaneous use of stones to crack nuts in a semi-free ranging group of tufted capuchin monkeys. Since then, we have found several more capuchin populations in savanna-like environments which(5-7) employ this form of tool use. The evidence so far only weakly supports geneti cally based behavioral differences between populations and does not suggest that dietary pressures in poor environments are proximate determinants of the likelihood of tool use. Instead, tool use within these capuchin populations seems to be a behavioral tradition that is socially learned and is primarily associated with more terrestrial habits. However, differences in the diversity of ""tool kits"" between populations remain to be understood.

Anatomical and radiographic appearance of the capuchin monkey thoracic cavity (Cebus apella)

The capuchin monkey is widespread both north and south of the Legal Amazon and in the Brazilian cerrado. Ten clinically healthy capuchin monkeys were submitted to an anatomical and radiographic study of their thoracic cavities. The radiographic evaluation allowed the description of biometric values associated with the cardiac silhouette and thoracic structures. Application of the VHS (vertebral heart size) method showed positive correlation (P<0.05) with depth of the thoracic cavity, as well as between the body length of vertebrae T 3, T 4, T 5 and T 6 and the cardiac length and width. The lung fields showed a diffuse interstitial pattern, more visible in the caudal lung lobes and a bronchial pattern in the middle and cranial lung lobes. The radiographic examination allowed preliminary inferences to be made concerning the syntopy of the thoracic structures and modifiication of the pulmonary patterns and cardiac anatomy for the capuchin monkey.

Intrinsic organization of the suprachiasmatic nucleus in the capuchin monkey

The suprachiasmatic nucleus (SCN), which is the main circadian biological clock in mammals, is composed of multiple cells that function individually as independent oscillators to express the self-sustained mRNA and protein rhythms of the so-called clock genes. Knowledge regarding the presence and localization of the proteins and neuroactive substances of the SCN are essential for understanding this nucleus and for its successful manipulation. Although there have been advances in the investigation of the intrinsic organization of the SCN in rodents, little information is available in diurnal species, especially in primates. This study, which explores the pattern of expression and localization of PER2 protein in the SCN of capuchin monkey, evaluates aspects of the circadian system that are common to both primates and rodents. Here, we showed that PER2 protein immunoreactivity is higher during the light phase. Additionally, the complex organization of cells that express vasopressin, vasoactive intestinal polypeptide, neuron-specific nuclear protein, calbindin and calretinin in the SCN, as demonstrated by their immunoreactivity, reveals an intricate network that may be related to the similarities and differences reported between rodents and primates in the literature.

Human TOP1 residues implicated in species specificity of HIV-1 infection are required for interaction with BTBD2, and RNAi of BTBD2 in old world monkey and human cells increases permissiveness to HIV-1 infection

Host determinants of HIV-1 viral tropism include factors from producer cells that affect the efficiency of productive infection and factors in target cells that block infection after viral entry. TRIM5 restricts HIV-1 infection at an early post-entry step through a mechanism associated with rapid disassembly of the retroviral capsid. Topoisomerase I (TOP1) appears to play a role in HIV-1 viral tropism by incorporating into or otherwise modulating virions affecting the efficiency of a post-entry step, as the expression of human TOP1 in African Green Monkey (AGM) virion-producing cells increased the infectivity of progeny virions by five-fold. This infectivity enhancement required human TOP1 residues 236 and 237 as their replacement with the AGM counterpart residues abolished the infectivity enhancement. Our previous studies showed that TOP1 interacts with BTBD1 and BTBD2, two proteins which co-localize with the TRIM5 splice variant TRIM5 in cytoplasmic bodies. Because BTBD1 and BTBD2 interact with one HIV-1 viral tropism factor, TOP1, and co-localize with a splice variant of another, we investigated the potential involvement of BTBD1 and BTBD2 in HIV-1 restriction.

In vivo evaluation in cynomolgus monkey brain and metabolism of [¹⁸F]fluorodeprenyl: a new MAO-B pet radioligand

In this study, we evaluated the in vivo characteristics of a new monoamine oxidase type B (MAO-B) radioligand, [¹⁸F]fluorodeprenyl, by positron emission tomography (PET) in two cynomolgus monkeys. The brain uptake of [¹⁸F]fluorodeprenyl was more than 7% (600% SUV) of the total injected radioactivity and similar to that of [¹¹C]deprenyl, an established MAO-B radioligand. The highest uptake was observed in the striatum, one of the MAO-B-rich regions, with a peak at approximately 2-3 min after injection, followed by lower uptake in the thalamus and the cortex and lowest uptake in the cerebellum. Brain uptake of [¹⁸F]fluorodeprenyl was largely inhibited by preadministration of the MAO-B inhibitor, L-deprenyl, whereas clorgyline, a MAO Type A blocker, had no significant inhibitory effect, thus demonstrating selectivity for MAO-B. [¹⁸F]Fluorodeprenyl showed relatively slow metabolism with the presence of two radiometabolite peaks with similar retention time as the labeled metabolites of [¹¹C]deprenyl. These results suggest that [¹⁸F]fluorodeprenyl is a potential PET radioligand for visualization of MAO-B activity.

Fenofibrate metabolism in the cynomolgus monkey using ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry-based metabolomics

Fenofibrate, widely used for the treatment of dyslipidemia, activates the nuclear receptor, peroxisome proliferator-activated receptor alpha. However, liver toxicity, including liver cancer, occurs in rodents treated with fibrate drugs. Marked species differences occur in response to fibrate drugs, especially between rodents and humans, the latter of which are resistant to fibrate-induced cancer. Fenofibrate metabolism, which also shows species differences, has not been fully determined in humans and surrogate primates. In the present study, the metabolism of fenofibrate was investigated in cynomolgus monkeys by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS)-based metabolomics. Urine samples were collected before and after oral doses of fenofibrate. The samples were analyzed in both positive-ion and negative-ion modes by UPLC-QTOFMS, and after data deconvolution, the resulting data matrices were subjected to multivariate data analysis. Pattern recognition was performed on the retention time, mass/charge ratio, and other metabolite-related variables. Synthesized or purchased authentic compounds were used for metabolite identification and structure elucidation by liquid chromatographytandem mass spectrometry. Several metabolites were identified, including fenofibric acid, reduced fenofibric acid, fenofibric acid ester glucuronide, reduced fenofibric acid ester glucuronide, and compound X. Another two metabolites (compound B and compound AR), not previously reported in other species, were characterized in cynomolgus monkeys. More importantly, previously unknown metabolites, fenofibric acid taurine conjugate and reduced fenofibric acid taurine conjugate were identified, revealing a previously unrecognized conjugation pathway for fenofibrate.

Multispecies Epidemiologic Surveillance Study after an Outbreak of Yersiniosis at an African Green Monkey Research Facility.

After an outbreak of Yersinia enterocolitica at a NHP research facility, we performed a multispecies investigation of the prevalence of Yersinia spp. in various mammals that resided or foraged on the grounds of the facility, to better understand the epizootiology of yersiniosis. Blood samples and fecal and rectal swabs were obtained from 105 captive African green monkeys (AGM), 12 feral cats, 2 dogs, 20 mice, 12 rats, and 3 mongooses. Total DNA extracted from swab suspensions served as template for the detection of Y. enterocolitica DNA by real-time PCR. Neither Y. enterocolitica organisms nor their DNA were detected from any of these samples. However, Western blotting revealed the presence of Yersinia antibodies in plasma. The AGM samples revealed a seroprevalence of 91% for Yersinia spp. and of 61% for Y. enterocolitica specifically. The AGM that were housed in cages where at least one fatality occurred during the outbreak (clinical group) had similar seroprevalence to that of AGM housed in unaffected cages (nonclinical group). However, the nonclinical group was older than the clinical group. In addition, 25%, 100%, 33%, 10%, and 10% of the sampled local cats, dogs, mongooses, rats, and mice, respectively, were seropositive. The high seroprevalence after this outbreak suggests that Y. enterocolitica was transmitted effectively through the captive AGM population and that age was an important risk factor for disease. Knowledge regarding local environmental sources of Y. enterocolitica and the possible role of wildlife in the maintenance of yersiniosis is necessary to prevent and manage this disease.

Ionotropic Glutamate Receptors Show Unique Distribution and Localization in the Dorsal Cochlear Nucleus of the Rhesus Monkey

The dorsal cochlear nucleus (DCN) receives auditory information via the auditory nerve coming from the cochlea. It is responsible for much of the integration of auditory information, and it projects this auditory information to higher auditory brain centers for further processing. This study focuses on the DCN of adult Rhesus monkeys to characterize two specific cell types, the fusiform and cartwheel cell, based on morphometric parameters and type of glutamate receptor they express. The fusiform cell is the main projection neuron, while the cartwheel cell is the main inhibitory interneuron. Expression of AMPA glutamate receptor subunits is localized to certain cell types. The activity of the CN depends on the AMPA receptor subunit composition and expression. Immunocytochemistry, using specific antibodies for AMPA glutamate receptor subunits GluR1, GluR2/3 and GluR4, was used in conjunction with morphometry to determine the location, morphological characteristics and expression of AMPA receptor subunits in fusiform and cartwheel cells in the primate DCN. Qualitative as well as quantitative data indicates that there are important morphological differences in cell location and expression of AMPA glutamate receptor subunits between the rodent DCN and that of primates. GluR2/3 is widely expressed in the primate DCN. GluR1 is also widely expressed in the primate DCN. GluR4 is diffusely expressed. Expression of GluR2/3 and GluR4 in the primate is similar to that of the rodent. However, expression of GluR1 is different. GluR1 is only expressed by cartwheel cells in the rodent DCN, but is expressed by a variety of cells, including fusiform cells, in the DCN of the primate.