| nerve growth factor promotes in vitro proliferation of neural stem cells from tree shrews. | neural stem cells promote neuronal regeneration and repair of brain tissue after injury, but have limited resources and proliferative ability in vivo. we hypothesized that nerve growth factor would promote in vitro proliferation of neural stem cells derived from the tree shrews, a primate-like mammal that has been proposed as an alternative to primates in biomedical translational research. we cultured neural stem cells from the hippocampus of tree shrews at embryonic day 38, and added nerve grow ... | 2016 | 27212919 |
| the recombined cccdna produced using minicircle technology mimicked hbv genome in structure and function closely. | hbv covalently closed circular dna (cccdna) is drug-resistant and responsible for viral persistence. to facilitate the development of anti-cccdna drugs, we developed a minicircle dna vector (mc)-based technology to produce large quantity of recombined cccdna (rcccdna) resembling closely to its wild-type counterpart both in structure and function. the rcccdna differed to the wild-type cccdna (wtcccdna) only in that it carried an extra 36-bp dna recombinant product attr upstream of the prec/c gene ... | 2016 | 27174254 |
| high activity of the stress promoter contributes to susceptibility to stress in the tree shrew. | stress is increasingly present in everyday life in our fast-paced society and involved in the pathogenesis of many psychiatric diseases. corticotrophin-releasing-hormone (crh) plays a pivotal role in regulating the stress responses. the tree shrews are highly vulnerable to stress which makes them the promising animal models for studying stress responses. however, the mechanisms underlying their high stress-susceptibility remained unknown. here we confirmed that cortisol was the dominate corticos ... | 2016 | 27125313 |
| erratum to: injection of aβ1-40 into hippocampus induced cognitive lesion associated with neuronal apoptosis and multiple gene expressions in the tree shrew. | | 2016 | 27055829 |
| development of a tree shrew metabolic syndrome model and use of umbilical cord mesenchymal stem cell transplantation for treatment. | the aim of this study was to establish a tree shrew metabolic syndrome model and demonstrate the utility of mscs in treating metabolic syndrome. we used tree shrew umbilical cord mesenchymal stem cell (ts-uc-msc) transplantation for the treatment of metabolic syndrome to demonstrate the clinical application of these stem cells and to provide a theoretical basis and reference methods for this treatment. tree shrew metabolic syndrome model showed significant insulin resistance, high blood sugar, l ... | 2016 | 27000263 |
| tree shrew as a new animal model for the study of lung cancer. | animal models play a key role in identifying treatments for various types of cancer, including lung cancer. the aim of the present study was to develop a new animal model for lung cancer induction using tree shrews from the yunnan region in china. tree shrews are suitable for a full simulation of human disease because their structure, function and metabolism are adequately close to human. this animal may offer a new experimental animal model to be used in the study of lung cancer. in the present ... | 2016 | 26998127 |
| a comparative analysis of the endocannabinoid system in the retina of mice, tree shrews, and monkeys. | the endocannabinoid (ecb) system is widely expressed in various parts of the central nervous system, including the retina. the localization of the key ecb receptors, particularly cb1r and cb2r, has been recently reported in rodent and primate retinas with striking interspecies differences. little is known about the distribution of the enzymes involved in the synthesis and degradation of these ecbs. we therefore examined the expression and localization of the main components of the ecb system in ... | 2016 | 26977322 |
| the effects of the auditory brainstem response before and after fluoro-gold injection in medial geniculate body. | this study aimed to use the tree shrew as an otological model, not only to verify the location of the auditory pathway in tree shrews by fluoro-gold (fg) but also to elucidate the effects of the auditory brainstem response (abr) before and after fg injection. | 2015 | 26921579 |
| injection of aβ1-40 into hippocampus induced cognitive lesion associated with neuronal apoptosis and multiple gene expressions in the tree shrew. | alzheimer's disease (ad) can incur significant health care costs to the patient, their families, and society; furthermore, effective treatments are limited, as the mechanisms of ad are not fully understood. this study utilized twelve adult male tree shrews (ts), which were randomly divided into pbs and amyloidbetapeptide1-40 (aβ1-40) groups. ad model was established via an intracerebroventricular (icv) injection of aβ1-40 after being incubated for 4 days at 37 °c. behavioral, pathophysiological ... | 2016 | 26897171 |
| neural coding of image structure and contrast polarity of cartesian, hyperbolic, and polar gratings in the primary and secondary visual cortex of the tree shrew. | we comprehensively characterize spiking and visual evoked potential (vep) activity in tree shrew v1 and v2 using cartesian, hyperbolic, and polar gratings. neural selectivity to structure of cartesian gratings was higher than other grating classes in both visual areas. from v1 to v2, structure selectivity of spiking activity increased, whereas corresponding vep values tended to decrease, suggesting that single-neuron coding of cartesian grating attributes improved while the cortical columnar org ... | 2016 | 26843607 |
| the effect of intravitreal injection of vehicle solutions on form deprivation myopia in tree shrews. | lntravitreal injection of substances dissolved in a vehicle solution is a common tool used to assess retinal function. we examined the effect of injection procedures (three groups) and vehicle solutions (four groups) on the development of form deprivation myopia (fdm) in juvenile tree shrews, mammals closely related to primates, starting at 24 days of visual experience (about 45 days of age). in seven groups (n = 7 per group), the myopia produced by monocular form deprivation (fd) was measured d ... | 2016 | 26836248 |
| refractive plasticity of the developing chick eye: a summary and update. | to summarize the opo 1992 classic paper: refractive plasticity of the developing chick eye (12: 448-452) and discuss recent findings in refractive development. | 2015 | 26497292 |
| effects of the synthetic neurosteroid: 3β-methoxypregnenolone (map4343) on behavioral and physiological alterations provoked by chronic psychosocial stress in tree shrews. | most currently available active antidepressant drugs are selective serotonin/noradrenaline reuptake inhibitors. however, as their clinical efficacy is not immediate, long-term administration is often accompanied by substantial side effects, and numerous patients remain non- or partial responders. we have recently found that the synthetic neurosteroid derivative 3β-methoxypregnenolone, which binds to the microtubule-associated protein-2, can provide a novel therapeutic approach in experimental mo ... | 2016 | 26476437 |
| dental maturation, eruption, and gingival emergence in the upper jaw of newborn primates. | in this report we provide data on dental eruption and tooth germ maturation at birth in a large sample constituting the broadest array of non-human primates studied to date. over 100 perinatal primates, obtained from natural captive deaths, were screened for characteristics indicating premature birth, and were subsequently studied using a combination of histology and micro-ct. results reveal one probable unifying characteristic of living primates: relatively advanced maturation of deciduous teet ... | 2015 | 26425925 |
| ultrastructure of geniculocortical synaptic connections in the tree shrew striate cortex. | to determine whether thalamocortical synaptic circuits differ across cortical areas, we examined the ultrastructure of geniculocortical terminals in the tree shrew striate cortex to compare directly the characteristics of these terminals with those of pulvinocortical terminals (examined previously in the temporal cortex of the same species; chomsung et al. [] cereb cortex 20:997-1011). tree shrews are considered to represent a prototype of early prosimian primates but are unique in that sublamin ... | 2016 | 26399201 |
| spatiotemporal profile of voltage-sensitive dye responses in the visual cortex of tree shrews evoked by electric microstimulation of the dorsal lateral geniculate and pulvinar nuclei. | the primary visual cortex (v1) receives its main thalamic drive from the dorsal lateral geniculate nucleus (dlgn) through synaptic contacts terminating primarily in cortical layer iv. in contrast, the projections from the pulvinar nucleus to the cortex are less clearly defined. the pulvinar projects predominantly to layer i in v1, and layer iv in extrastriate areas. these projection patterns suggest that the pulvinar nucleus most strongly influences (drives) activity in cortical areas beyond v1. ... | 2015 | 26311771 |
| [study of the changes on tree shrew bronchial epithelium
induced by xuanwei bituminous coal dust]. | lung cancer is the type of cancer with the highest incidence and mortality in numerous countries and regions. establishing an appropriate animal model that can be used to simulate lung cancer etiology, pathogenesis, and similar processes, is urgent. we explore the feasibility of establishing a lung cancer model induced by xuanwei bituminous coal dust pm10 (particulate matter with diameters of 10 μm or less), which affects bronchial epithelium of tree shrews. | 2015 | 26302342 |
| the formation and extinction of fear memory in tree shrews. | fear is an emotion that is well-studied due to its importance for animal survival. experimental animals, such as rats and mice, have been widely used to model fear. however, higher animals such as nonhuman primates have rarely been used to study fear due to ethical issues and high costs. tree shrews are small mammals that are closely related to primates; they have been used to model human-related psychosocial conditions such as stress and alcohol tolerance. here, we describe an experimental para ... | 2015 | 26283941 |
| human and tree shrew alpha-synuclein: comparative cdna sequence and protein structure analysis. | the synaptic protein alpha-synuclein (α-syn) is associated with a number of neurodegenerative diseases, and homology analyses among many species have been reported. nevertheless, little is known about the cdna sequence and protein structure of α-syn in tree shrews, and this information might contribute to our understanding of its role in both health and disease. we designed primers to the human α-syn cdna sequence; then, tree shrew α-syn cdna was obtained by rt-pcr and sequenced. based on the ac ... | 2015 | 26265394 |
| establishment of the tree shrew as an alcohol-induced fatty liver model for the study of alcoholic liver diseases. | currently, the pathogenesis of alcoholic liver diseases (alds) is not clear. as a result, there is no effective treatment for alds. one limitation is the lack of a suitable animal model for use in studying alds. the tree shrew is a lower primate animal, characterized by a high-alcohol diet. this work aimed to establish a fatty liver model using tree shrews and to assess the animals' suitability for the study of alds. tree shrews were treated with alcohol solutions (10% and 20%) for two weeks. he ... | 2015 | 26030870 |
| bony labyrinth morphometry indicates locomotor adaptations in the squirrel-related clade (rodentia, mammalia). | the semicircular canals (scs) of the inner ear detect angular acceleration and are located in the bony labyrinth of the petrosal bone. based on high-resolution computed tomography, we created a size-independent database of the bony labyrinth of 50 mammalian species especially rodents of the squirrel-related clade comprising taxa with fossorial, arboreal and gliding adaptations. our sampling also includes gliding marsupials, actively flying bats, the arboreal tree shrew and subterranean species. ... | 2015 | 26019162 |
| the modified hole board--measuring behavior, cognition and social interaction in mice and rats. | this protocol describes the modified hole board (mhb), which combines features from a traditional hole board and open field and is designed to measure multiple dimensions of unconditioned behavior in small laboratory mammals (e.g., mice, rats, tree shrews and small primates). this paradigm is a valuable alternative for the use of a behavioral test battery, since a broad behavioral spectrum of an animal's behavioral profile can be investigated in one single test. the apparatus consists of a box, ... | 2015 | 25938188 |
| changing material properties of the tree shrew sclera during minus lens compensation and recovery. | to estimate two collagen-specific material properties (crimp angle and elastic modulus of collagen fibrils) of the remodeling tree shrew sclera during monocular -5 diopter (d) lens wear and recovery. | 2015 | 25736788 |
| scleral gene expression during recovery from myopia compared with expression during myopia development in tree shrew. | during postnatal refractive development, the sclera receives retinally generated signals that regulate its biochemical properties. hyperopic refractive error causes the retina to produce "go" signals that, through the direct emmetropization pathway, cause scleral remodeling that increases the axial elongation rate of the eye, reducing the hyperopia. myopia causes the retina to generate "stop" signals that produce scleral remodeling, slowing the axial elongation rate and reducing the myopia. our ... | 2014 | 25540576 |
| the position of tree shrews in the mammalian tree: comparing multi-gene analyses with phylogenomic results leaves monophyly of euarchonta doubtful. | the well-accepted euarchonta grandorder is a pruned version of archonta nested within the euarchontoglires (or supraprimates) clade. at present, it includes tree shrews (scandentia), flying lemurs (dermoptera) and primates (primates). here, a phylogenomic dataset containing 1912 exons from 22 representative mammals was compiled to investigate the phylogenetic relationships within this group. phylogenetic analyses and hypothesis testing suggested that tree shrews can be classified as a sister gro ... | 2015 | 25311886 |
| varied behavioral responses induced by morphine in the tree shrew: a possible model for human opiate addiction. | tree shrews represent a suitable animal model to study the pathogenesis of human diseases as they are phylogenetically close to primates and have a well-developed central nervous system that possesses many homologies with primates. therefore, in our study, we investigated whether tree shrews can be used to explore the addictive behaviors induced by morphine. firstly, to investigate the psychoactive effect of morphine on tree shrews' behavior, the number of jumping and shuttling, which represent ... | 2014 | 25294994 |
| gene expression signatures in tree shrew choroid in response to three myopiagenic conditions. | we examined gene expression in tree shrew choroid in response to three different myopiagenic conditions: minus lens (ml) wear, form deprivation (fd), and continuous darkness (dk). four groups of tree shrews (n=7 per group) were used. starting 24 days after normal eye opening (days of visual experience [dve]), the ml group wore a monocular -5d lens for 2 days. the fd group wore a monocular translucent diffuser for 2 days. the dk group experienced continuous darkness binocularly for 11 days, start ... | 2014 | 25072854 |
| bone-marrow mesenchymal stem cell transplantation to treat diabetic nephropathy in tree shrews. | diabetic nephropathy (dn) is a common microvascular complication of diabetes. we used a new dn model in tree shrews to validate the use of bone-marrow mesenchymal stem cell (bm-msc) transplantation to treat dn. the dn tree shrew model was established by a high-sugar and high-fat diet and four injections of streptozotocin. 4',6-diamidino-2-phenylindole labelled bm-mscs were injected into tree shrews. the dn tree shrew model was successfully established. blood glucose was significantly increased ( ... | 2014 | 24867093 |
| mapping bone cell distributions to assess ontogenetic origin of primate midfacial form. | midfacial reduction in primates has been explained as a byproduct of other growth patterns, especially the convergent orbits. this is at once an evolutionary and developmental explanation for relatively short snouts in most modern primates. here, we use histological sections of perinatal nonhuman primates (tamarin, tarsier, loris) to investigate how orbital morphology emerges during ontogeny in selected primates compared to another euarchontan (tupaia glis). we annotated serial histological sect ... | 2014 | 24861725 |
| ndrg2 as a marker protein for brain astrocytes. | the protein ndrg2 (n-myc downregulated gene 2) is expressed in astrocytes. we show here that ndrg2 is located in the cytosol of protoplasmic and fibrous astrocytes throughout the mammalian brain, including bergmann glia as observed in mouse, rat, tree shrew, marmoset and human. ndrg2 immunoreactivity is detectable in the astrocytic cell bodies and excrescencies including fine distal processes. glutamatergic and gabaergic nerve terminals are associated with ndrg2 immunopositive astrocytic process ... | 2014 | 24816982 |
| gene expression signatures in tree shrew choroid during lens-induced myopia and recovery. | gene expression in tree shrew choroid was examined during the development of minus-lens induced myopia (lim, a go condition), after completion of minus-lens compensation (a stay condition), and early in recovery (rec) from induced myopia (a stop condition). five groups of tree shrews (n = 7 per group) were used. starting 24 days after normal eye-opening (days of visual experience [dve]), one minus-lens group wore a monocular -5 d lens for 2 days (lim-2), another minus-lens group achieved stable ... | 2014 | 24742494 |
| optogenetic assessment of horizontal interactions in primary visual cortex. | columnar organization of orientation selectivity and clustered horizontal connections linking orientation columns are two of the distinctive organizational features of primary visual cortex in many mammalian species. however, the functional role of these connections has been harder to characterize. here we examine the extent and nature of horizontal interactions in v1 of the tree shrew using optical imaging of intrinsic signals, optogenetic stimulation, and multi-unit recording. surprisingly, we ... | 2014 | 24695715 |
| phylogenetic affinity of tree shrews to glires is attributed to fast evolution rate. | previous phylogenetic analyses have led to incongruent evolutionary relationships between tree shrews and other suborders of euarchontoglires. what caused the incongruence remains elusive. in this study, we identified 6845 orthologous genes between seventeen placental mammals. tree shrews and primates were monophyletic in the phylogenetic trees derived from the first or/and second codon positions whereas tree shrews and glires formed a monophyly in the trees derived from the third or all codon p ... | 2014 | 24333622 |
| gene expression signatures in tree shrew sclera in response to three myopiagenic conditions. | we compared gene expression signatures in tree shrew sclera produced by three different visual conditions that all produce ocular elongation and myopia: minus-lens wear, form deprivation, and dark treatment. | 2013 | 24045991 |
| agomelatine in the tree shrew model of depression: effects on stress-induced nocturnal hyperthermia and hormonal status. | the antidepressive drug agomelatine combines the properties of an agonist of melatonergic receptors 1 and 2 with an antagonist of the 5-ht2c receptor. we analyzed the effects of agomelatine in psychosocially stressed male tree shrews, an established preclinical model of depression. tree shrews experienced daily social stress for a period of 5 weeks and were concomitantly treated with different drugs daily for 4 weeks. the effects of agomelatine (40 mg/kg/day) were compared with those of the agon ... | 2014 | 23978391 |
| transformation of receptive field properties from lateral geniculate nucleus to superficial v1 in the tree shrew. | tree shrew primary visual cortex (v1) exhibits a pronounced laminar segregation of inputs from different classes of relay neurons in the lateral geniculate nucleus (lgn). we examined how several receptive field (rf) properties were transformed from lgn to v1 layer 4 to v1 layer 2/3. the progression of rf properties across these stages differed markedly from that found in the cat. v1 layer 4 cells are largely similar to the the lgn cells that provide their input, being dominated by a single sign ... | 2013 | 23843520 |
| faster scaling of auditory neurons in cortical areas relative to subcortical structures in primate brains. | allometric studies in primates have shown that the cerebral cortex, cerebellum, and remaining brain structures increase in size as a linear function of their numbers of neurons and nonneuronal cells across primates. whether such scaling rules also apply to functionally related structures such as those of the auditory system is unknown. here, we investigate the scaling of brain structures in the auditory pathway of six primate species and the closely related tree shrew. using the isotropic fracti ... | 2013 | 23712070 |
| on the relation between receptive field structure and stimulus selectivity in the tree shrew primary visual cortex. | there are notable differences in functional properties of primary visual cortex (v1) neurons among mammalian species, particularly those concerning the occurrence of simple and complex cells and the generation of orientation selectivity. here, we present quantitative data on receptive field (rf) structure, response modulation, and orientation tuning for single neurons in v1 of the tree shrew, a close relative of primates. we find that spatial rf subfield segregation, a criterion for identifying ... | 2014 | 23696278 |
| light levels, refractive development, and myopia--a speculative review. | recent epidemiological evidence in children indicates that time spent outdoors is protective against myopia. studies in animal models (chick, macaque, tree shrew) have found that light levels (similar to being in the shade outdoors) that are mildly elevated compared to indoor levels, slow form-deprivation myopia and (in chick and tree shrew) lens-induced myopia. normal chicks raised in low light levels (50 lux) with a circadian light on/off cycle often develop spontaneous myopia. we propose a mo ... | 2013 | 23680160 |
| [measurement and analysis of anatomical parameter values in tree shrews]. | anatomical parameter values in tree shrews are major biological characteristic indicators in laboratory animals. body size, bones and mammilla, organ weights, coefficient intestinal canal and other anatomical data were measured and analyzed in laboratory domesticated tree shrews (7 to 9 months of age). measurement of 31 anatomical parameters showed that body height, width of the right ear, ileum and colon had significant differences between males and females (p<0.05). highly significant differen ... | 2013 | 23572364 |
| [molecular evidence on the phylogenetic position of tree shrews]. | the tree shrew is currently located in the order scandentia and is widely distributed in southeast asia, south asia, and south china. due to its unique characteristics, such as small body size, high brain-to-body mass ratio, short reproductive cycle and life span, and low-cost of maintenance, the tree shrew has been proposed as an alternative experimental animal to primates in biomedical research. however, there is unresolved debate regarding the phylogenetic affinity of tree shrews to primates ... | 2013 | 23572355 |
| response to interrupted hyperopia after restraint of axial elongation in tree shrews. | to determine if early restraint of axial elongation in response to plus lenses increases the subsequent response to interrupted hyperopia in tree shrews. | 2013 | 23314128 |
| neuropeptide alterations in the tree shrew hypothalamus during volatile anesthesia. | neuropeptides are critical signaling molecules, involved in the regulation of diverse physiological processes including energy metabolism, pain perception and brain cognitive state. prolonged general anesthesia has an impact on many of these processes, but the regulation of peptides by general anesthetics is poorly understood. in this study, we present an in-depth characterization of the hypothalamic neuropeptides of the tree shrew during volatile isoflurane/nitrous oxide anesthesia administered ... | 2013 | 23228960 |
| inferring host specificity and network formation through agent-based models: tick-mammal interactions in borneo. | patterns of host-parasite association are poorly understood in tropical forests. while we typically observe only snapshots of the diverse assemblages and interactions under variable conditions, there is a desire to make inferences about prevalence and host-specificity patterns. we studied the interaction of ticks with non-volant small mammals in forests of borneo. we inferred the probability of species interactions from individual-level data in a multi-level bayesian model that incorporated envi ... | 2013 | 23108423 |
| tuning of color contrast signals to visual sensitivity maxima of tree shrews by three bornean highland nepenthes species. | three species of nepenthes pitcher plants (nepenthes rajah, nepenthes lowii and nepenthes macrophylla) specialize in harvesting nutrients from tree shrew excreta in their pitchers. in all three species, nectaries on the underside of the pitcher lid are the focus of the tree shrews' attention. tree shrews are dichromats, with visual sensitivity in the blue and green wavebands. all three nepenthes species were shown to produce visual signals, in which the underside of the pitcher lid (the area of ... | 2012 | 22902686 |
| cortical networks for ethologically relevant behaviors in primates. | parietal-frontal networks in primate brains are central to mediating actions. physiological and anatomical investigations have shown that the parietal-frontal network is consistently organized across several branches of primate evolution that include prosimian galagos, new world owl and squirrel monkeys, and old world macaque monkeys. electrical stimulation with 0.5-sec trains of pulses delivered via microelectrodes evoked ethologically relevant actions from both posterior parietal cortex (ppc) ... | 2013 | 22865408 |
| high levels of gene expression in the hepatocytes of adult mice, neonatal mice and tree shrews via retro-orbital sinus hydrodynamic injections of naked plasmid dna. | hydrodynamic-based gene delivery has emerged as an efficient and simple method for the intracellular transfection of naked plasmid dna (pdna) in vivo. in this system, a hydrodynamic injection via the tail vein is the most effective non-viral method of liver-targeted gene delivery. however, this injection is often technically challenging when used in animals whose tail veins are difficult to visualize or too small to operate on. to overcome this limitation, an alternative in vivo gene delivery me ... | 2012 | 22609275 |
| analysis of multiple quaternary ammonium compounds in the brain using tandem capillary column separation and high resolution mass spectrometric detection. | endogenous quaternary ammonium compounds are involved in various physiological processes in the central nervous system. in the present study, eleven quaternary ammonium compounds, including acetylcholine, choline, carnitine, acetylcarnitine and seven other acylcarnitines of low polarity, were analyzed from brain extracts using a two dimension capillary liquid chromatography-fourier transform mass spectrometry method. to deal with their large difference in hydrophobicities, tandem coupling betwee ... | 2012 | 22533909 |
| chromosome painting of the pygmy tree shrew shows that no derived cytogenetic traits link primates and scandentia. | we hybridized human chromosome paints on metaphases of the pygmy tree shrew (tupaia minor, scandentia). the lack of the ancestral mammalian 4/8 association in both primates and scandentia was long considered a cytogenetic landmark that phylogenetically linked these mammalian orders. however, our results show that the association 4/8 is present in tupaia along with not previously reported associations for 1/18 and 7/10. altogether there are 11 syntenic associations of human chromosome segments in ... | 2012 | 22488112 |
| functional and laminar dissociations between muscarinic and nicotinic cholinergic neuromodulation in the tree shrew primary visual cortex. | acetylcholine is an important neuromodulator involved in cognitive function. the impact of cholinergic neuromodulation on computations within the cortical microcircuit is not well understood. here we investigate the effects of layer-specific cholinergic drug application in the tree shrew primary visual cortex during visual stimulation with drifting grating stimuli of varying contrast and orientation. we describe differences between muscarinic and nicotinic cholinergic effects in terms of both th ... | 2012 | 22487086 |
| statistical structure of lateral connections in the primary visual cortex. | the statistical structure of the visual world offers many useful clues for understanding how biological visual systems may understand natural scenes. one particularly important early process in visual object recognition is that of grouping together edges which belong to the same contour. the layout of edges in natural scenes have strong statistical structure. one such statistical property is that edges tend to lie on a common circle, and this 'co-circularity' can predict human performance at con ... | 2011 | 22330062 |
| broad characterization of endogenous peptides in the tree shrew visual system. | endogenous neuropeptides, acting as neurotransmitters or hormones in the brain, carry out important functions including neural plasticity, metabolism and angiogenesis. previous neuropeptide studies have focused on peptide-rich brain regions such as the striatum or hypothalamus. here we present an investigation of peptides in the visual system, composed of brain regions that are generally less rich in peptides, with the aim of providing the first broad overview of peptides involved in mammalian v ... | 2012 | 22326962 |
| the effect of daily transient +4 d positive lens wear on the inhibition of myopia in the tree shrew. | negative-lens-induced defocus causes accelerated ocular elongation and myopia, whereas positive-lens-induced defocus produces reduced ocular elongation and hyperopia. short durations of positive lens wear result in markedly stronger temporal effects than do short periods of negative lens wear in the chick model of refractive development. in mammalian and nonhuman primate models, there have been equivocal results in inhibiting myopia by short periods of positive lens wear when compared with data ... | 2012 | 22323488 |
| inner ear evolution in primates through the cenozoic: implications for the evolution of hearing. | mammals are unique in being the only group of amniotes that can hear sounds in the upper frequency range (>12 khz), yet details about the evolutionary development of hearing patterns remain poorly understood. in this study, we used high resolution x-ray computed tomography to investigate several functionally relevant auditory structures of the inner ear in a sample of 21 fossil primate species (60 ma to recent times) and 25 species of living euarchontans (primates, tree shrews, and flying lemurs ... | 2012 | 22282428 |
| thalamic burst firing propensity: a comparison of the dorsal lateral geniculate and pulvinar nuclei in the tree shrew. | relay neurons in dorsal thalamic nuclei can fire high-frequency bursts of action potentials that ride the crest of voltage-dependent transient (t-type) calcium currents [low-threshold spike (lts)]. to explore potential nucleus-specific burst features, we compared the membrane properties of dorsal lateral geniculate nucleus (dlgn) and pulvinar nucleus relay neurons using in vitro whole-cell recording in juvenile and adult tree shrew (tupaia) tissue slices. we injected current ramps of variable sl ... | 2011 | 22114295 |
| alterations in protein expression in tree shrew sclera during development of lens-induced myopia and recovery. | during the development of, and recovery from, negative lens-induced myopia there is regulated remodeling of the scleral extracellular matrix (ecm) that controls the extensibility of the sclera. difference gel electrophoresis (dige) was used to identify and categorize proteins whose levels are altered in this process. | 2012 | 22039233 |
| diffuse and specific tectopulvinar terminals in the tree shrew: synapses, synapsins, and synaptic potentials. | the pulvinar nucleus of the tree shrew receives both topographic (specific) and nontopographic (diffuse) projections from superior colliculus (sc), which form distinct synaptic arrangements. we characterized the physiological properties of these synapses and describe two distinct types of excitatory postsynaptic potentials (epsps) that correlate with structural properties of the specific and diffuse terminals. synapses formed by specific terminals were found to be significantly longer than those ... | 2011 | 21858222 |
| nocturnal hyperthermia induced by social stress in male tree shrews: relation to low testosterone and effects of age. | stress is known to elevate core body temperature (cbt). we recorded cbt in a diurnal animal, the male tree shrew, during a one-week control period and a one-week period of social stress using a telemetric system. during the stress period, when animals were confronted with a dominant male for about 1h daily, cbt was increased throughout the day. we analyzed cbt during the night when animals were left undisturbed and displayed no locomotor activity. to determine whether nocturnal hyperthermia may ... | 2011 | 21827778 |
| patterns of mrna and protein expression during minus-lens compensation and recovery in tree shrew sclera. | to increase our understanding of the mechanisms that remodel the sclera during the development of lens-induced myopia, when the sclera responds to putative "go" signals of retinal origin, and during recovery from lens-induced myopia, when the sclera responds to retinally-derived "stop" signals. | 2011 | 21541268 |
| toll-like receptor 4 is involved in ischemic tolerance of postconditioning in hippocampus of tree shrews to thrombotic cerebral ischemia. | toll-like receptor 4 (tlr4) is an important mediator of the innate immune response. it significantly contributes to neuroinflammation and may be involved in ischemic tolerance. it is unknown how cerebral ischemia in the cortex and postconditioning might affect inflammatory reactions in the hippocampus or whether tlr4 expression plays a role. | 2011 | 21315690 |
| mutualism between tree shrews and pitcher plants: perspectives and avenues for future research. | three species of nepenthes pitcher plants from borneo engage in a mutualistic interaction with mountain tree shrews, the basis of which is the exchange of nutritional resources. the plants produce modified "toilet pitchers" that produce copious amounts of exudates, the latter serving as a food source for tree shrews. the exudates are only accessible to the tree shrews when they position their hindquarters over the pitcher orifice. tree shrews mark valuable resources with faeces and regularly def ... | 2010 | 20861680 |
| the representation of s-cone signals in primary visual cortex. | recent studies of middle-wavelength-sensitive and long-wavelength-sensitive cone responses in primate primary visual cortex (v1) have challenged the view that color and form are represented by distinct neuronal populations. individual v1 neurons exhibit hallmarks of both color and form processing (cone opponency and orientation selectivity), and many display cone interactions that do not fit classic chromatic/achromatic classifications. comparable analysis of short-wavelength-sensitive (s) cone ... | 2010 | 20685977 |
| trap geometry in three giant montane pitcher plant species from borneo is a function of tree shrew body size. | *three bornean pitcher plant species, nepenthes lowii, n. rajah and n. macrophylla, produce modified pitchers that 'capture' tree shrew faeces for nutritional benefit. tree shrews (tupaia montana) feed on exudates produced by glands on the inner surfaces of the pitcher lids and defecate into the pitchers. *here, we tested the hypothesis that pitcher geometry in these species is related to tree shrew body size by comparing the pitcher characteristics with those of five other 'typical' (arthropod- ... | 2010 | 20100203 |
| comparative functional morphology of the primate peroneal process. | the first metatarsal of living primates is characterized by a well-developed peroneal process, which appears proportionally larger in prosimians than in anthropoids. a large peroneal process has been hypothesized to: 1) reflect powerful hallucal grasping, 2) act as a buttress to reduce strain from loads acting on the entocuneiform-first metatarsal joint during landing and grasping after a leap, and/or 3) correlate with differences in physiological abduction of the hallux. in this study, we addre ... | 2009 | 19765802 |
| synaptic organization of connections between the temporal cortex and pulvinar nucleus of the tree shrew. | we examined the synaptic organization of reciprocal connections between the temporal cortex and the dorsal (pd) and central (pc) subdivisions of the tree shrew pulvinar nucleus, regions innervated by the medial and lateral superior colliculus, respectively. both pd and pc subdivisions project topographically to 2 separate regions of the temporal cortex; small injections of anterograde tracers placed in either pd or pc labeled 2 foci of terminals in the temporal cortex. pulvinocortical pathways i ... | 2010 | 19684245 |
| a precise form of divisive suppression supports population coding in the primary visual cortex. | the responses of neurons in the primary visual cortex (v1) to an optimally oriented grating are suppressed when a non-optimal grating is superimposed. although cross-orientation suppression is thought to reflect mechanisms that maintain a distributed code for orientation, the effect of superimposed gratings on v1 population responses is unknown. using intrinsic signal optical imaging, we found that patterns of tree shrew v1 activity evoked by superimposed equal-contrast gratings were predicted b ... | 2009 | 19396165 |
| possible mechanisms of cyclosporin a ameliorated the ischemic microenvironment and inhibited mitochondria stress in tree shrews' hippocampus. | the ischemic brain damage is always accompanied by the significant accumulation of glutamate and calcium ions (ca(2+)). our objectives were to observe the effects of glutamate and ca(2+) overloading in tree shrew's hippocampal microenvironment on mitochondrial stress resulting in cytochrome c release and caspase apoptotic gene activation, and to explore the possible mechanism of cyclosporin a (csa) inhibiting mitochondrial stress. | 2009 | 19303263 |
| expression of muscarinic receptor subtypes in tree shrew ocular tissues and their regulation during the development of myopia. | muscarinic receptors are known to regulate several important physiologic processes in the eye. antagonists to these receptors such as atropine and pirenzepine are effective at stopping the excessive ocular growth that results in myopia. however, their site of action is unknown. this study details ocular muscarinic subtype expression within a well documented model of eye growth and investigates their expression during early stages of myopia induction. | 2009 | 19262686 |
| retinal and choroidal tgf-beta in the tree shrew model of myopia: isoform expression, activation and effects on function. | a visually evoked signalling cascade, which begins in the retina, transverses the choroid, and mediates scleral remodelling, is considered to control eye growth. the ubiquitous cytokine tgf-beta has been associated with alterations in ocular growth, where alterations in scleral tgf-beta isoforms mediate the scleral remodelling that results in myopia. however, while the tgf-beta isoforms have been implicated in the scleral change during myopia development, it is unclear whether alterations in ret ... | 2009 | 19046968 |
| sonu20176289, a compound combining partial dopamine d(2) receptor agonism with specific serotonin reuptake inhibitor activity, affects neuroplasticity in an animal model for depression. | we investigated the efficacy of sonu20176289, a member of a group of novel phenylpiperazine derivatives with a mixed dopamine d(2) receptor partial agonist and specific serotonin reuptake inhibitor (ssri) activity, in a chronic stress model of depression in male tree shrews. animals were subjected to a 7-day period of psychosocial stress before treatment for 28 days with sonu20176289 (6 mg/kg/day, p.o.), during which stress was maintained. stress reduced the in vivo brain concentrations of n-ace ... | 2008 | 18822282 |
| ultrastructural examination of diffuse and specific tectopulvinar projections in the tree shrew. | two pathways from the superior colliculus (sc) to the tree shrew pulvinar nucleus have been described, one in which the axons terminate in dense (or specific) patches and one in which the axon arbors are more diffusely organized (luppino et al. [1988] j. comp. neurol. 273:67-86). as predicted by lyon et al. ([2003] j. comp. neurol. 467:593-606), we found that anterograde labeling of the diffuse tectopulvinar pathway terminated in the acetylcholinesterase (ache)-rich dorsal pulvinar (pd), whereas ... | 2008 | 18615501 |
| the effect of positive lens defocus on ocular growth and emmetropization in the tree shrew. | optical defocus influences postnatal ocular development in animal models. induced negative lens defocus results in accelerated ocular elongation and myopia. positive lens-induced defocus findings across animal models have been inconsistent. specifically, in the tree shrew, positive lens-induced defocus has produced equivocal results. this study evaluated the response of the tree shrew to induced positive lens defocus. one treatment group wore positive lenses binocularly, which were increased in ... | 2008 | 18484807 |
| layer 2/3 synapses in monocular and binocular regions of tree shrew visual cortex express machr-dependent long-term depression and long-term potentiation. | acetylcholine is an important modulator of synaptic efficacy and is required for learning and memory tasks involving the visual cortex. in rodent visual cortex, activation of muscarinic acetylcholine receptors (machrs) induces a persistent long-term depression (ltd) of transmission at synapses recorded in layer 2/3 of acute slices. although the rodent studies expand our knowledge of how the cholinergic system modulates synaptic function underlying learning and memory, they are not easily extrapo ... | 2008 | 18480372 |
| colugos: obscure mammals glide into the evolutionary limelight. | substantial molecular evidence indicates that tree-shrews, colugos and primates cluster together on the mammalian phylogenetic tree. previously, a sister-group relationship between colugos and primates seemed likely. a new study of colugo chromosomes indicates instead an affinity between colugos and tree-shrews. | 2008 | 18466644 |
| intrinsic hand proportions of euarchontans and other mammals: implications for the locomotor behavior of plesiadapiforms. | arboreal primates have distinctive intrinsic hand proportions compared with many other mammals. within euarchonta, platyrrhines and strepsirrhines have longer manual proximal phalanges relative to metacarpal length than colugos and terrestrial tree shrews. this trait is part of a complex of features allowing primates to grasp small-diameter arboreal substrates. in addition to many living and eocene primates, relative elongation of proximal manual phalanges is also present in most plesiadapiforms ... | 2008 | 18440594 |
| chronic psychosocial stress affects corticotropin-releasing factor in the paraventricular nucleus and central extended amygdala as well as urocortin 1 in the non-preganglionic edinger-westphal nucleus of the tree shrew. | stressful stimuli evoke neuronal and neuroendocrine responses helping an organism to adapt to changed environmental conditions. chronic stressors may induce maladaptive responses leading to psychiatric diseases, such as anxiety and major depression. a suitable animal model to unravel mechanisms involved in the control of adaptation to chronic stress is the psychological subordination stress in the male tree shrew. subordinate male tree shrews exhibit chronic hypothalamo-pituitary-adrenal (hpa) a ... | 2008 | 18394812 |
| frontal fusion: collapse of another anthropoid synapomorphy. | we test the hypothesis that the fused interfrontal suture of anthropoids is a uniquely distinguishing feature and a derived characteristic indicative of their monophyletic origin. our survey of nonanthropoid primates and several archontan families indicates frontal fusion is widespread. it is most variable (fused, open or partially fused) inter- and intra-specifically among strepsirhines. the frontal bone is more commonly fused in living lemuroids and indrioids than among lorisoids. it appears t ... | 2008 | 18231970 |
| spermiogenesis and chromatin condensation in the common tree shrew, tupaia glis. | we have investigated the cellular characteristics, especially chromatin condensation and the basic nuclear protein profile, during spermiogenesis in the common tree shrew, tupaia glis. spermatids could be classified into golgi phase, cap phase, acrosome phase, and maturation phase. during the golgi phase, chromatin was composed of 10-nm and 30-nm fibers with few 50-nm to 60-nm knobby fibers. the latter were then transformed into 70-nm knobby fibers during the cap phase. in the acrosome phase, al ... | 2008 | 18095001 |
| selective modulation of scleral proteoglycan mrna levels during minus lens compensation and recovery. | to better characterize the role of proteoglycans in scleral tissue remodeling during the development of minus lens induced myopia and during recovery in tree shrews. | 2007 | 17960126 |
| improving effect of ginkgolide b on mitochondrial respiration of ischemic neuron after cerebral thrombosis in tree shrewa. | it has been known that platelet activating factor receptors (pafr) may mediate many acute pathological responses and that pafr antagonist ginkgolide b (gb) possesses multiple effects, but the actions of gb on pafr affinity and mitochondrial respiration in the ischemic neuron were unclear until now. this study explored the possible effects of gb on pafr and the mitochondrial respiration of the neuron in the ischemic microenvironment. | 2007 | 17908463 |
| first evidence of melatonin receptors distribution in the suprachiasmatic nucleus of tree shrew brain. | in this study we investigated the distribution of melatonergic receptors in the tree shrew brain. the psychosocial stress in the tree shrew is a validated model of depression with disturbance of circadian rhythms. | 2007 | 17627260 |
| modulation of glycosaminoglycan levels in tree shrew sclera during lens-induced myopia development and recovery. | in juvenile tree shrews, positioning a negative-power lens in front of an eye produces a hyperopic shift in refractive state and causes a compensatory increase in axial length over several days so that the eye is myopic when the lens is removed. during negative lens compensation, the scleral extracellular matrix is remodeled. a biomechanical property of the sclera, creep rate, increases; during recovery from induced myopia, the creep rate decreases below normal levels. changes in glycosaminoglyc ... | 2007 | 17591859 |
| [the effect of ginkgolide b on astrocyte gfap expression after the focal cerebral ischemia]. | to observe the effect of platelet activating factor (paf) antagonist, ginkgolide b (gb), on the expression of glial fibrillary acidic protein (gfap) in astrocytes during focal cerebral ischemia, of which the mechanism will be explored too. | 2007 | 17441350 |
| neurogenesis and depression: what animal models tell us about the link. | there is growing evidence that stress causes a decrease of neurogenesis in the dentate gyrus and antidepressant treatment in turn stimulates the cell proliferation in the dentate gyrus. this has led to the hypothesis that a decreased neurogenesis might be linked to the pathophysiology of major depression. the article reviews the relationship of depressive-like behavior and neurogenesis in three animal models of depression with high validity: learned helplessness, chronic mild stress and chronic ... | 2007 | 17401725 |
| luminance-evoked inhibition in primary visual cortex: a transient veto of simultaneous and ongoing response. | large-scale changes in luminance are known to exert a significant suppressive or masking effect on visual perception, but the neural substrate for this effect remains unclear. in this report, we describe the results of experiments using in vivo intracellular recording to explore the impact of luminance transients on the responses of orientation-selective neurons in layer 2/3 of tree shrew primary visual cortex. by measuring changes in excitatory and inhibitory conductances, we find that instanta ... | 2006 | 17192437 |
| darkness causes myopia in visually experienced tree shrews. | to examine the effect of a period of continuous darkness on the refractive state and vitreous chamber depth of normal light-reared juvenile tree shrew eyes, and to learn whether eyes that developed myopia in response to monocular minus-lens wear will recover in darkness. | 2006 | 17065476 |
| effectiveness of hyperopic defocus, minimal defocus, or myopic defocus in competition with a myopiagenic stimulus in tree shrew eyes. | to examine the ability of hyperopic defocus, minimal defocus, and myopic defocus to compete against a myopiagenic -5-d lens in juvenile tree shrew eyes. | 2006 | 17065475 |
| expression of collagen-binding integrin receptors in the mammalian sclera and their regulation during the development of myopia. | the sclera has a collagen-rich extracellular matrix that undergoes significant biochemical and biomechanical remodeling during myopic eye growth. the integrin family of cell surface receptors play critical roles in extracellular matrix and biomechanical remodeling in connective tissues. this study identified the major collagen-binding integrin receptors in the mammalian sclera and investigated their mrna expression during the development of and recovery from experimental myopia. | 2006 | 17065473 |
| [repetitive sequences of the tree shrew genome (mammalia, scandentia)]. | copies of two repetitive elements of the genome of common tree shrew (tupaia glis) were cloned and sequenced. the first element, tu iii, is a approximately 260 bp long short interspersed element (sine) with the 5'-end derived from glycine rna. tu iii carries long polypurine- and polypyrimidine-rich tracts, which may contribute to the specific secondary structure of tu iii rna. this sine was also found in the genome of smooth-tailed tree shrew of another genus (dendrogale). tu iii seems to be con ... | 2006 | 16523694 |
| microvascularization of thalamus and metathalamus in common tree shrew (tupaia glis). | the microangioarchitecture of the thalamus and metathalamus in common tree shrew (tupaia glis) was studied using vascular corrosion cast/stereomicroscope and sem technique. the arterial supply of the thalamus and metathalamus was found to originate from perforating branches of the posterior communicating artery, the posterior cerebral artery, the middle cerebral artery, and the anterior choroidal artery. these perforating arteries gave rise to numerous bipinnate arterioles which in turn, with de ... | 2006 | 16456678 |
| astroglial plasticity in the hippocampus is affected by chronic psychosocial stress and concomitant fluoxetine treatment. | analysis of post-mortem tissue from patients with affective disorders has revealed a decreased number of glial cells in several brain areas. here, we examined whether long-term psychosocial stress influences the number and morphology of hippocampal astrocytes in an animal model with high validity for research on the pathophysiology of major depression. adult male tree shrews were submitted to 5 weeks of psychosocial stress, after which immunocytochemical and quantitative stereological techniques ... | 2006 | 16395301 |
| [a cdna microarray study of the differential expression of genes in signal transduction pathway during hepatocarcinogenesis in tree shrews]. | to study the differential expression of genes in signal transduction pathway (stp) during the hepatocarcinogenesis in tree shrews induced by afb1 and/or hbv and to elucidate the molecular mechanism of hepatocellular carcinoma (hcc) development. | 2005 | 16248950 |
| selective regulation of mmp and timp mrna levels in tree shrew sclera during minus lens compensation and recovery. | in juvenile tree shrews, a minus-power lens placed in front of the eye produces increased axial elongation and a myopic shift in refractive state that compensates for the power of the lens. scleral tissue remodeling and modulation of the mechanical properties of the sclera occur during lens compensation. in this study, the time course of changes in scleral mrna levels of three mmps and three timps during compensation for a minus lens and during recovery was investigated, to determine which, if a ... | 2005 | 16186323 |
| types of vascular wall as related to vasa vasorum in common tree shrew (tupaia glis). | blood vessels of the common tree shrew (tupaia glis) were embedded in araldite, sectioned at 0.5-1 microm thickness, and observed with light microscope (lm). it was found that the vascular wall could be classified into three categories: (1) those with proper vasa vasorum (pvv); (2) those with collaborative vasa vasorum in perimural tissues; (3) those without vasa vasorum. the pvv were located in the the tunica media, between the tunica media and the tunica adventitia, and in the tunica adventiti ... | 2005 | 16173094 |
| dynamic expression of apoptosis-related genes during development of laboratory hepatocellular carcinoma and its relation to apoptosis. | to explore the expression of p53, bcl-2, bax, survivin and the cell apoptosis during the development of tree shrew hepatocellular carcinoma (hcc), the relationship between expression of these genes, its impact on hcc development, and its relation to cell apoptosis. | 2005 | 16094721 |
| age-dependent susceptibility of adult hippocampal cell proliferation to chronic psychosocial stress. | stress inhibits neurogenesis in the adult dentate gyrus. it is not known, however, whether age has any influence on this process. we subjected adult male tree shrews to 5 weeks of psychosocial stress, after which dentate cytogenesis was determined using brdu immunohistochemistry. we found that older animals were significantly more vulnerable to the adverse effect of stress on dentate cell proliferation. | 2005 | 15950198 |
| 5-ht1a receptor expression in pyramidal neurons of cortical and limbic brain regions. | we studied expression of the 5-ht(1a) receptor in cortical and limbic areas of the brain of the tree shrew. in situ hybridization with a receptor-specific probe and immunocytochemistry with various antibodies was used to identify distinct neurons expressing the receptor. in vitro receptor autoradiography with (3)h-8-oh-dpat ((3)h-8-hydroxy-2-[di-n-propylamino]tetralin) was performed to visualize receptor-binding sites. in the prefrontal, insular, and occipital cortex, 5-ht(1a) receptor mrna was ... | 2005 | 15947971 |
| chronic psychosocial stress in tree shrews: effect of the substance p (nk1 receptor) antagonist l-760735 and clomipramine on endocrine and behavioral parameters. | substance p and its preferred receptor, the neurokinin 1 receptor (nk(1)r), have been proposed as possible targets for new antidepressant therapies, although results of a recently completed phase iii trial failed to demonstrate that the nk(1)r antagonist mk-869 is more effective than placebo in the treatment of depression. | 2005 | 15875166 |
| evolution of base-substitution gradients in primate mitochondrial genomes. | inferences of phylogenies and dates of divergence rely on accurate modeling of evolutionary processes; they may be confounded by variation in substitution rates among sites and changes in evolutionary processes over time. in vertebrate mitochondrial genomes, substitution rates are affected by a gradient along the genome of the time spent being single-stranded during replication, and different types of substitutions respond differently to this gradient. the gradient is controlled by biological fa ... | 2005 | 15867428 |
| examining slv-323, a novel nk1 receptor antagonist, in a chronic psychosocial stress model for depression. | substance p antagonists have been proposed as candidates for a new class of antidepressant compounds. | 2005 | 15726334 |