KEPADATAN TULANG METACARPAL SIMPANSE USIA 0 SAMPAI 44 TAHUN

Sifat fisik tulang merupakan indikator yang baik untuk studi pertumbuhan dan penuaan. Tulang adalah jaringan dinamis karena adanya proses modeling dan remodeling. Tulang berubah tidak hanya pada ukuran dan bentuknya, tetapi juga kepadatannya yang disebabkan karena perubahan kandungan mineralnya. Osteoporosis atau kekeroposan tulang merupakan salah satu tanda umum penuaaan manusia. Osteoporosis di kalangan anthropoid masih belum diketahui. Dalam penelitian ini kami melakukan pengukuran kepadatan korteks tulang metacarpal simpanse (Pan troglodytes) usia 0 sampai 44 tahun berdasarkan radiografi. Pengukuran dilakukan dengan metode mikro-densitometri pada 68 simpanse betina dan 49 simpanse jantan. Kami menemukan bahwa kepadatan tulang meningkat pesat sampai usia sekitar 10 tahun. Pada simpanse jantan kepadatan tulangnya terus meningkat sampai usia 44 tahun, sedangkan pada simpanse betina kepadatan tulangnya menurun mulai usia 20 tahun. Penurunan kepadatan tulang simpanse betina dapat disebabkan karena kalsium tulang digunakan pada masa kehamilan dan menyusui. Namun demikian, simpanse betina diketahui tidak mengalami menopause. Jadi tidak seperti wanita, kejadian osteoporosis pada simpanse betina bukanlah ak ibat dari menopause. Kemungkinan hal ini berkaitan dengan berkurangnya kadar estrogen pada simpanse lanjut usia. Kata Kunci: osteoporosis, kepadatan tulang, metakarpal, simpans

KEPADATAN TULANG METACARPAL SIMPANSE USIA 0 SAMPAI 44 TAHUN

ABSTRAK   Sifat fisik tulang merupakan indikator yang baik untuk studi pertumbuhan dan penuaan. Tulang adalah jaringan dinamis karena adanya proses modeling dan remodeling. Tulang berubah tidak hanya pada ukuran dan bentuknya, tetapi juga kepadatannya yang disebabkan  karena perubahan kandungan mineralnya. Osteoporosis atau kekeroposan tulang merupakan salah satu tanda umum penuaaan manusia. Osteoporosis di kalangan anthropoid masih belum diketahui. Dalam penelitian ini kami melakukan pengukuran kepadatan korteks tulang metacarpal simpanse (Pan troglodytes) usia 0 sampai 44 tahun berdasarkan radiografi. Pengukuran dilakukan dengan metode mikro-densitometri pada 68 simpanse betina dan 49 simpanse jantan. Kami menemukan bahwa kepadatan tulang meningkat pesat sampai usia sekitar 10 tahun. Pada simpanse jantan kepadatan tulangnya terus meningkat sampai usia 44 tahun, sedangkan pada simpanse betina kepadatan tulangnya menurun mulai usia 20 tahun. Penurunan kepadatan tulang simpanse betina dapat disebabkan karena kalsium tulang digunakan pada masa kehamilan dan menyusui. Namun demikian, simpanse betina diketahui tidak mengalami menopause. Jadi tidak seperti wanita, kejadian osteoporosis pada simpanse betina bukanlah akibat dari menopause. Kemungkinan hal ini berkaitan dengan berkurangnya kadar estrogen pada simpanse lanjut usia.   Kata Kunci: osteoporosis, kepadatan tulang, metakarpal, simpans

Growth Pattern of Body Size in Baduy People

Understanding body size growth pattern is one of the best ways to find out biological variation in phenotypic plasticity, health and nutritional statuses, and quality of life. Optimum environment and better nutrition are associated with rapid growth, tall stature, and early puberty. However, poor living condition impacts every stage of development, which results in variation in growth rates, growth periods, and body sizes across populations. Baduy is one of traditional populations who inhabit mountainous area in Kanekes Village, Lebak Regency, Banten Province, Indonesia. The traditional obligatory duties and taboos resulted in genetic, geographic, and cultural isolations. This leads to question whether the biocultural condition affects the growth pattern of their body size. We measured the body height, weight, and mass index of 340 girls and 239 boys aged 4–30 years sampled from 39 of 61 hamlets using cross-sectional method. We found that Baduy people had prolonged growth resulting in small body size because of slow rate and low spurt. This might be a selection to save body maintenance costs in biocultural condition with poor nutrition and high physical activity

Prolonged maturation of prefrontal white matter in chimpanzees

Delayed maturation in the prefrontal cortex, a brain region associated with complex cognitive processing, has been proposed to be specific to humans. However, we found, using a longitudinal design, that prefrontal white matter volume in chimpanzees increased gradually with age, and the increase appears to continue beyond the onset of puberty, as in humans. This provides the first evidence for a prolonged period of prefrontal connection elaboration in great apes

Ontogenetic Allometry of Body Height and Body Mass of Girl in Baduy, Indonesia

Several small-scale populations exhibited phenotypic plasticity whereby growth spurt of body height occurred much earlier than age at menarche and this was not followed by same early spurt of body weight. This leads to question whether growth trajectory of stature follow the same growth trajectory of body mass and whether the trajectory itself is associated to sexual maturity. We evaluated developmental plasticity observed in Baduy girl, a traditional population in Indonesia, in facing strenuous environmental and biocultural conditions. We measured stature and body mass cross-sectionally. We determined age at menarche as population average of age of girls that had already got their first menstruation. Growths of body fat and weight followed a same mode and timing and their spurts pivoted on the age at menarche. In contrast, growth spurt of body height occurred four years earlier than menarche and velocity curve of body linearity progressed in opposite direction to that of body ponderality. The prevailing poor nutrition and high physical activity elicited principle of ontogenetic allometry to synchronize the acceleration and deceleration of growths in body linearity and ponderality whereby growth in body height functions to reach the body size target and to provide skeletal framework for development of body mass. The biocultural conditions lead to slow bodily growth rate with low spurt resulting in the characteristics of Baduy girl that was small in size and late in both sexual maturity and full-grown ages

Secondary contact and genomic admixture between rhesus and long‐tailed macaques in the Indochina Peninsula

Understanding the process and consequences of hybridization is one of the major challenges in evolutionary biology. A growing body of literature has reported evidence of ancient hybridization events or natural hybrid zones in primates, including humans; however, we still have relatively limited knowledge about the pattern and history of admixture because there have been little studies that simultaneously achieved genome‐scale analysis and a geographically wide sampling of wild populations. Our study applied double‐digest restriction site‐associated DNA sequencing to samples from the six localities in and around the provisional hybrid zone of rhesus and long‐tailed macaques and evaluated population structure, phylogenetic relationships, demographic history, and geographic clines of morphology and allele frequencies. A latitudinal gradient of genetic components was observed, highlighting the transition from rhesus (north) to long‐tailed macaque distribution (south) as well as the presence of one northern population of long‐tailed macaques exhibiting unique genetic structure. Interspecific gene flow was estimated to have recently occurred after an isolation period, and the migration rate from rhesus to long‐tailed macaques was slightly greater than in the opposite direction. Although some rhesus macaque‐biased alleles have widely introgressed into long‐tailed macaque populations, the inflection points of allele frequencies have been observed as concentrated around the traditionally recognized interspecific boundary where morphology discontinuously changed; this pattern was more pronounced in the X chromosome than in autosomes. Thus, due to geographic separation before secondary contact, reproductive isolation could have evolved, contributing to the maintenance of an interspecific boundary and species‐specific morphological characteristics

The Japan Monkey Centre Primates Brain Imaging Repository for comparative neuroscience: an archive of digital records including records for endangered species

Advances in magnetic resonance imaging (MRI) and computational analysis technology have enabled comparisons among various primate brains in a three-dimensional electronic format. Results from comparative studies provide information about common features across primates and species-specific features of neuroanatomy. Investigation of various species of non-human primates is important for understanding such features, but the majority of comparative MRI studies have been based on experimental primates, such as common marmoset, macaques, and chimpanzee. A major obstacle has been the lack of a database that includes non-experimental primates’ brain MRIs. To facilitate scientific discoveries in the field of comparative neuroanatomy and brain evolution, we launched a collaborative project to develop an open-resource repository of non-human primate brain images obtained using ex vivo MRI. As an initial open resource, here we release a collection of structural MRI and diffusion tensor images obtained from 12 species: pygmy marmoset, owl monkey, white-fronted capuchin, crab-eating macaque, Japanese macaque, bonnet macaque, toque macaque, Sykes’ monkey, red-tailed monkey, Schmidt’s guenon, de Brazza’s guenon, and lar gibbon. Sixteen postmortem brain samples from the 12 species, stored in the Japan Monkey Centre (JMC), were scanned using a 9.4-T MRI scanner and made available through the JMC collaborative research program (http://www.j-monkey.jp/BIR/index_e.html). The expected significant contributions of the JMC Primates Brain Imaging Repository include (1) resources for comparative neuroscience research, (2) preservation of various primate brains, including those of endangered species, in a permanent digital form, (3) resources with higher resolution for identifying neuroanatomical features, compared to previous MRI atlases, (4) resources for optimizing methods of scanning large fixed brains, and (5) references for veterinary neuroradiology. User-initiated research projects beyond these contributions are also anticipated

The Japan Monkey Centre Primates Brain Imaging Repository of high-resolution postmortem magnetic resonance imaging: the second phase of the archive of digital records

超高磁場MRIで見る霊長類「全脳」神経回路の多様性 --分野横断型の霊長類脳標本画像リポジトリ：ヒト脳と精神・神経疾患の理解を加速する国際研究基盤--. 京都大学プレスリリース. 2023-05-22.A comparison of neuroanatomical features of the brain between humans and our evolutionary relatives, nonhuman primates, is key to understanding the human brain system and the neural basis of mental and neurological disorders. Although most comparative MRI studies of human and nonhuman primate brains have been based on brains of primates that had been used as subjects in experiments, it is essential to investigate various species of nonhuman primates in order to elucidate and interpret the diversity of neuroanatomy features among humans and nonhuman primates. To develop a research platform for this purpose, it is necessary to harmonize the scientific contributions of studies with the standards of animal ethics, animal welfare, and the conservation of brain information for long-term continuation of the field. In previous research, we first developed a gated data-repository of anatomical images obtained using 9.4-T ex vivo MRI of postmortem brain samples from 12 nonhuman primate species, and which are stored at the Japan Monkey Centre. In the present study, as a second phase, we released a collection of T2-weighted images and diffusion tensor images obtained in nine species: white-throated capuchin, Bolivian squirrel monkey, stump-tailed macaque, Tibet monkey, Sykes’ monkey, Assamese macaque, pig-tailed macaque, crested macaque, and chimpanzee. Our image repository should facilitate scientific discoveries in the field of comparative neuroscience. This repository can also promote animal ethics and animal welfare in experiments with nonhuman primate models by optimizing methods for in vivo and ex vivo MRI scanning of brains and supporting veterinary neuroradiological education. In addition, the repository is expected to contribute to conservation, preserving information about the brains of various primates, including endangered species, in a permanent digital form

Developmental trajectory of the corpus callosum from infancy to the juvenile stage: Comparative MRI between chimpanzees and humans

[email protected] brains develop during early life is one of the most important topics in neuroscience because it underpins the neuronal functions that mature during this period. A comparison of the neurodevelopmental patterns among humans and nonhuman primates is essential to infer evolutional changes in neuroanatomy that account for higher-order brain functions, especially those specific to humans. The corpus callosum (CC) is the major white matter bundle that connects the cerebral hemispheres, and therefore, relates to a wide variety of neuronal functions. In humans, the CC area rapidly expands during infancy, followed by relatively slow changes. In chimpanzees, based on a cross-sectional study, slow changes in the CC area during the juvenile stage and later have also been reported. However, little is known about the developmental changes during infancy. A longitudinal study is also required to validate the previous cross-sectional observations about the chimpanzee CC. The present longitudinal study of magnetic resonance imaging scans demonstrates that the CC development in chimpanzees and humans is characterized by a rapid increase during infancy, followed by gradual increase during the juvenile stage. Several differences between the two species were also identified. First, there was a tendency toward a greater increase in the CC areas during infancy in humans. Second, there was a tendency toward a greater increase in the rostrum during the juvenile stage in chimpanzees. The rostral body is known to carry fibers between the bilateral prefrontal and premotor cortices, and is involved in behavior planning and control, verbal working memory, and number conception. The rostrum is known to carry fibers between the prefrontal cortices, and is involved in attention control. The interspecies differences in the developmental trajectories of the rostral body and the rostrum might be related to evolutional changes in the brain systems. © 2017 Sakai et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited