| plague foci in viet nam: zoological and parasitological aspects. | reported are the results of studies over the period 1989-94 on host-flea complexes in small mammals and their flea ectoparasites in and around a number of human settlements in viet nam in which human cases of plague had been found. collections were also made in savanna and tropical forest areas within a 10-km radius of the settlements. the greatest numbers of small mammals, for the most part rattus spp., and of the flea ectoparasite xenopsylla cheopis were found in inhabited areas. x. cheopis wa ... | 1997 | 9185363 |
| active emmetropization--evidence for its existence and ramifications for clinical practice. | there is increasing evidence from animal studies in support of the concept of an active emmetropization mechanism which has potentially important clinical ramifications for the management of refractive errors. recent research into refractive development and emmetropization is reviewed, with emphasis given to work involving the chick, tree shrew and monkey, which represent the three most widely used animal models in this field. the findings of this research are reviewed in a clinical context. com ... | 1997 | 9390372 |
| proliferation of granule cell precursors in the dentate gyrus of adult monkeys is diminished by stress. | although granule cells continue to be added to the dentate gyrus of adult rats and tree shrews, this phenomenon has not been demonstrated in the dentate gyrus of adult primates. to determine whether neurons are produced in the dentate gyrus of adult primates, adult marmoset monkeys (callithrix jacchus) were injected with brdu and perfused 2 hr or 3 weeks later. brdu is a thymidine analog that is incorporated into proliferating cells during s phase. a substantial number of cells in the dentate gy ... | 1998 | 9501234 |
| effects of gamma-aminobutyric acid, progesterone and ionophore a23187 on acrosome reaction of tree shrew sperm in vitro: examination of acrosome reaction with an improved fluorescence microscopy. | a number of acrosome reaction (ar) initiators have been found to be effective in inducing ar of human, laboratory and domestic animal sperm. using an improved simple fluorescence microscopy, effects of gamma-aminobutyric acid (gaba), progesterone and ionophore a23187 on sperm ar of tree shrew, a useful animal model in biomedical research, have been investigated. spontaneous ar in 4.92-7.53% of viable sperm was observed. complete ar in 10.31-18.25% of viable tree shrew sperm was obviously induced ... | 1997 | 9505115 |
| structural organization of a conserved gene cluster of tupaia herpesvirus encoding the dna polymerase, glycoprotein b, a probable processing and transport protein, and the major dna binding protein. | the tupaia herpesviruses (thvs) have been isolated from malignant lymphoma tissue cultures and from degenerating lung and spleen cell cultures of tree shrews (tupaia spp.). recently we succeeded in the localization of the gene locus of the thv dna polymerase (dpol) gene within the viral genome. based on these results the highly conserved gene cluster of herpesviruses encoding the dpol, the glycoprotein b (gb), a probable processing and transport protein (prtp), and the major dna binding protein ... | 1999 | 10392721 |
| sharp vision: a prerequisite for compensation to myopic defocus in the chick? | compensatory responses to focusing errors imposed by spectacle lenses in chicks, tree shrews and primates leave little doubt that active emmetropization can occur, and debate is now centered on whether this process is uni-directional or bi-directional in nature. to provide further insight into this emmetropization process, the studies reported in this paper addressed the question of whether access to sharp vision is necessary for compensation to myopic defocus in the chick. | 1998 | 9543642 |
| classes of axons and their distribution in the optic nerve of the tree shrew (tupaia belangeri). | it has been suggested that retinal ganglion cells (rgcs) of tupaia can be subdivided into three classes that correspond to the x, y, and w classes in the cat. estimates of these classes as determined by electrophysiological experiments and by histological studies of the retina are at variance. because the rgc classes differ in axon diameter, this parameter could serve as a reliable criterion for the evaluation of rgc classes and their proportions. | 1997 | 9294655 |
| serological evidence of natural infection of wild rodents (rattus spp and tupaia glis) with rickettsiae in malaysia. | | 1998 | 10437957 |
| comparative studies on mammalian müller (retinal glial) cells. | müller cells from 22 mammalian species were subjected to morphological and electrophysiological studies. in the 'midperiphery' of retinae immunocytochemically labeled for vimentin, estimates of müller cell densities per unit retinal surface area, and of neuron-to-(müller) glia indices were performed. müller cell densities were strikingly similar among the species studied (around 8000-11,000 mm-2) with the extremes of the horse (< or = 5000 mm-2) and the tree shrew (> or = 20,000 mm-2). by contra ... | 1997 | 9306243 |
| cloning of glucocorticoid receptor and mineralocorticoid receptor cdna and gene expression in the central nervous system of the tree shrew (tupaia belangeri). | the glucocorticoid (gr) and the mineralocorticoid (mr) receptor mediate corticosteroid actions in the mammalian brain. here, we report the sequence and distribution of both receptor subtype mrnas in the central nervous system of the tree shrew tupaia belangeri, a non-rodent mammal, phylogenetically located between insectivores and primates. the specific glucocorticoid and mineralocorticoid receptor cdnas were cloned, employing polymerase chain reaction (pcr) based methods. the gr cdna and mr cdn ... | 1998 | 9582428 |
| transmission of hepatitis c virus infection to tree shrews. | although hepatitis c virus (hcv) infection can be reproduced in chimpanzees, these animals are rare and expensive. tree shrews (tupaias) are small animals, closely related to primates, which adapt easily to a laboratory environment. in this work we have investigated the susceptibility of tupaia belangeri chinensis to hcv infection. tupaias caught in the wild in yunnan (china) were inoculated in china with hcv genotype 1b (study a) and in spain with a mixture of genotypes 1b, 1a, and 3 (study b). ... | 1998 | 9601519 |
| cryptococcosis in tree shrews (tupaia tana and tupaia minor) and elephant shrews (macroscelides proboscides). | fungal infections due to cryptococcus neoformans occurred in seven short-eared elephant shrews (macroscelides proboscides), six large tree shrews (tupaia tana), and five lesser tree shrews (tupaia minor) at the national zoological park during a 30-mo period in 1991-1993. clinical signs were absent or included weight loss, shivering, dyspnea, and/or neurologic disease. definitive antemortem diagnostic techniques included tracheal lavage and serum cryptococcal antigen latex agglutination titers. t ... | 1997 | 9279407 |
| synergistic effect of hepatitis b virus and aflatoxin b1 in hepatocarcinogenesis in tree shrews. | an animal experiment with tree shrews was performed to detect the synergistic effects of hepatitis b virus (hbv) infection and dietary aflatoxin b1 (afb1) in hepatocarcinogenesis. adult healthy tree shrews (tupaia belangeri chinensis) were divided into four groups: group a (hbv + afb1)--animals were infected with human hbv serum at first, then fed afb1 diluted with milk, 150 ug/kg.bw/day, 6 days/week for 105 weeks. group b (hbv)--animals were infected with human hbv as group a, but no afb1 treat ... | 1999 | 10374028 |
| effect of interrupted lens wear on compensation for a minus lens in tree shrews. | when a young animal wears a monocular minus (concave) lens that shifts the focal plane away from the cornea, the vitreous chamber elongates over a period of days, shifting the retinal location to compensate for the altered focal plane. we examined the effect of removing the lens for a portion of each day on the amount of compensation in tree shrews. | 1999 | 10375247 |
| fmrfamide immunoreactivity and the invasion of adenohypophyseal cells into the neural lobe in the developing pituitary of the tree shrew tupaia belangeri. | ontogenetic development of fmrfamide immunoreactivity in the cells and nerve fibers of the pituitary was studied in the tree shrew tupaia belangeri. up to the 26th day of gestation (e26), no fmrfamide immunoreactivity was visible. from e27 onwards it increased continuously until prenatally, on e41, the adult pattern was reached in the adenohypophysis, although at a lower intensity. in the adult tupaia, as in the other mammals studied so far, a finely stained fmrfamide-immunoreactive fiber networ ... | 1999 | 10407096 |
| two related g protein-coupled receptors: the distribution of gpr7 in rat brain and the absence of gpr8 in rodents. | gpr7 and gpr8, orphan g protein-coupled receptor (gpcr) genes, expressed in the brain and periphery share highest sequence identity to each other and significant similarity with opioid and somatostatin receptors. to further our knowledge of gpr7's physiological function, we performed in situ hybridization analyses of rat brain to reveal specific patterns of expression in the brain. gpr7 mrna was found to be discretely localized in areas of the amygdala, hippocampus, hypothalamus and cortex. we p ... | 1999 | 10407191 |
| immunohistochemical survey of the gut endocrine cells in the common tree shrew (tupaia belangeri). | regional distribution and relative frequency of endocrine cells in the gastrointestinal tract of the common tree shrew (tupaia belangeri) were studied immunohistochemically. ten types of immunoreactive endocrine cells were localized in the gastric mucosa, i.e., chromogranin-, serotonin-, gastrin-, somatostatin-, bovine pancreatic polypeptide (bpp)-, enteroglucagon-, pancreatic glucagon-, peptide tyrosine tyrosine (pyy)-, motilin-, and substance p (sp)-immunoreactive (ir) cells. in the intestine, ... | 1999 | 10458098 |
| primate-like amyloid-beta sequence but no cerebral amyloidosis in aged tree shrews. | a central pathological feature of alzheimer's disease is the profuse deposition of amyloid-beta protein (abeta) in the brain parenchyma and vessel walls. abeta also forms deposits in the brains of a variety of mammals, including all aged non-human primates studied to date. the sequence of abeta in these animals is identical to that in humans. no abeta deposits have been found in the brains of wild-type rats and mice, suggesting that the three amino acid differences between their abeta and that o ... | 1999 | 10466892 |
| spontaneous tumours in tree shrews (tupaia belangeri): population studies. | in a necropsy series at the german primate centre, 63 of 1132 tree shrews were found to have tumours. the youngest affected animal was < 6 months old, but the incidence of tumours increased strikingly beyond 2 years of age; of 17 animals aged > 8 years, no less than 14 (82.4%) were affected. the sites of neoplasia were the genital system (22 cases), haematopoietic system (18 cases of malignant lymphoma, many involving the digestive tract), lungs (14 cases), integument (five cases), digestive tra ... | 1998 | 9651807 |
| age-related levels of urinary free cortisol in the tree shrew. | there are still controversies concerning the effect of aging on the basal glucocorticoid concentration in mammals, including humans. some studies reported an elevated glucocorticoid concentration in older subjects, while other reports showed no increases with age. these discrepancies may be caused by different experimental designs, gender differences, or varying sampling time points. the bulk of animal studies reporting increases of glucocorticoids with age were performed in rats. the present st ... | 1998 | 9733169 |
| attenuation of hippocampal 11beta-hydroxysteroid dehydrogenase type 1 by chronic psychosocial stress in the tree shrew. | 11beta-hydroxysteroid dehydrogenase type 1 (11beta-hsd-1) catalyses the interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone, thus regulating glucocorticoid access to intracellular receptors. in rats, chronic glucocorticoid excess or stress increases 11beta-hsd-1 in the hippocampus, producing suggestions that it may attenuate the deleterious effects of chronic glucocorticoid excess. however, 11beta-hsd-1 predominantly catalyses 11beta-reduction ... | 1997 | 9787261 |
| immunocytochemical localization of the postsynaptic density protein psd-95 in the mammalian retina. | synapse-associated proteins are the scaffold for the selective aggregation of ion channels at synapses; they provide the link to cytoskeletal elements and possibly are involved with the regulation of synaptic efficacy by electrical activity. the localization of the postsynaptic density protein psd-95 was studied in different mammalian retinae (rat, monkey, and tree shrew) by using immunocytochemical methods. immunofluorescence for psd-95 was most prominent in the outer plexiform layer (opl). the ... | 1998 | 9822767 |
| differential effects of chronic stress on memory processes in the tree shrew. | unpredictable and uncontrollable stressful events have been shown to affect cognitive processes. interestingly, only hippocampus-mediated memory processes are thought to be sensitive to the effects of chronic stress. in contrast, the hippocampus-independent memory processes have been shown to be resistant to chronic stressful experiences. a central feature of the stress response is the activation of the hypothalamus-pituitary-adrenocortical (hpa)-axis, resulting in increased plasma levels of glu ... | 1999 | 9838198 |
| corticotropin-releasing factor receptor type 1 from tupaia belangeri--cloning, functional expression and tissue distribution. | a cdna clone encoding corticotropin-releasing factor (crf) type 1 (crf-r1) has been isolated from the tree shrew tupaia belangeri with a pcr-based approach. the full-length cdna encoded a 415-amino-acid protein with highest sequence identity (approximately 98%) to human crf-r1 and slightly less identity to rat or mouse crf-r1 (approximately 97%). only eight amino acids (residues 3, 4, 6, 35, 36 and 39 in the n-terminus, residue 232 in transmembrane domain 4 and residue 410 in the c-terminus) dif ... | 1998 | 9851694 |
| [clinical and experimental study on treatment of chronic hepatitis b with yanggan aoping mixture]. | to assess the efficacy of yanggan aoping mixture (ygapm) in treating hepatitis b. | 1997 | 9863082 |
| identification and characterization of the tupaia herpesvirus dna polymerase gene. | tupaia herpesviruses (thvs) have been isolated from malignant lymphomas and from degenerating lung or spleen cell cultures of tree shrews (tupoia spp.), but because of a lack of genetic information the final classification of thvs is still open. in the present work the viral dna polymerase (dpol) gene was mapped within the genome of the different thv strains using pcr and degenerate oligonucleotide primers. nucleotide sequences of the dpol genes of thv strains 1 to 5 were determined and used for ... | 1998 | 9880021 |
| the susceptible period for deprivation-induced myopia in tree shrew. | to examine the susceptible period for deprivation-induced myopia, six groups of tree shrew pups (tupaia glis belangeri) were monocularly deprived for 12 days with an opaque occluder starting 7, 15, 21, 33, 48, or 63 days after natural eyelid opening. compared to the untreated fellow control eye, significant myopia and vitreous chamber elongation were produced by the deprivation in all six groups. the effect was greater in the middle three groups in comparison with the youngest and the two oldest ... | 1998 | 9893785 |
| prk-induced anisometropia in the rabbit as a model of myopia. | current animal models of myopia, such as the chick and the tree shrew, have characteristics that limit their applicability to human myopia and/or their use among researchers. the purpose of this study was to establish a rabbit model of myopia based on photorefractive keratectomy (prk)-induced anisometropia. | 1999 | 9987634 |
| borna disease virus: new aspects on infection, disease, diagnosis and epidemiology. | a 'disease of the head' affecting horses, as described in the 17th century is now known as borna disease. research over the past 100 years has established that the aetiological agent, borna disease virus (bdv), is an unsegmented, single- and negative-stranded, enveloped ribonucleic acid (rna) virus which represents the family bornaviridae in the order mononegavirales. the virus exists world-wide in horses, sheep, cattle, cats, dogs and ostriches. the infection can be fatal, but the majority of c ... | 2000 | 11189720 |
| hippocampal neurogenesis in adult old world primates. | the production of new hippocampal neurons in adulthood has been well documented in rodents. recent studies have extended these findings to other mammalian species, such as tree shrews and marmoset monkeys. however, hippocampal neurogenesis has not been demonstrated in adult old world primates. to investigate this possibility, we injected 11 adult old world monkeys of different ages (5-23 years) with the thymidine analog bromodeoxyuridine and examined the fate of the labeled cells at different su ... | 1999 | 10220454 |
| cellular distribution of the calcium-binding proteins parvalbumin, calbindin, and calretinin in the neocortex of mammals: phylogenetic and developmental patterns. | the three calcium-binding proteins parvalbumin, calbindin, and calretinin are found in morphologically distinct classes of inhibitory interneurons as well as in some pyramidal neurons in the mammalian neocortex. although there is a wide variability in the qualitative and quantitative characteristics of the neocortical subpopulations of calcium-binding protein-immunoreactive neurons in mammals, most of the available data show that there is a fundamental similarity among the mammalian species inve ... | 1999 | 10223310 |
| organization of somatosensory areas i and ii in marsupial cerebral cortex: parallel processing in the possum sensory cortex. | organization of somatosensory areas i and ii in marsupial cerebral cortex: parallel processing in the possum sensory cortex. controversy exists over the organization of mammalian thalamocortical somatosensory networks. an issue of particular contention is whether the primary and secondary somatosensory areas of cortex (si and sii) are organized in a parallel or serial scheme for processing tactile information. the current experiments were conducted in the anesthetized brush-tail possum (trichosu ... | 1999 | 10322068 |
| isolation and pharmacological characterization of two functional splice variants of corticotropin-releasing factor type 2 receptor from tupaia belangeri. | from brain, heart and muscle tissue of the tree shrew (tupaia belangeri), a higher order mammal, cdna clones were isolated that encoded two functional splice variants of the corticotropin-releasing factor (crf) type 2 receptor (crf-r2). the first, full-length splice variant, amplified from brain and heart tissue, encoded a crf receptor protein that is 410 amino acids in length and approximately 96% homologous to human crf-r2alpha. the second, full-length splice variant, derived from skeletal mus ... | 1999 | 10336722 |
| isolation and molecular characterization of a novel cytopathogenic paramyxovirus from tree shrews. | a cytopathic infectious agent was isolated from the kidneys of an apparently healthy tree shrew (tupaia belangeri) that had been captured in the area around bangkok. the infectivity was propagated in tupaia fibroblast and kidney cell cultures. paramyxovirus-like pleomorphic enveloped particles and helical nucleocapsids were observed by electron microscopy and accordingly the infectious agent was termed tupaia paramyxovirus (tpmv). however, no serological cross-reactions were detected between tpm ... | 1999 | 10366580 |
| the expression of insulin-like growth factor ii, hepatitis b virus x antigen and p21 in experimental hepatocarcinogenesis in tree shrews. | the purpose of this paper was to study the mechanism of synergistic effect in hepatocarcinogenesis induced by hepatitis b virus (hbv) infection and aflatoxin b1 (afb1) intake. immunohistochemical staining was used in formalin-fixed, paraffin-embedded sections of cancer and liver tissues. the incidence of hepatocellular carcinomas (hccs) was 52.9% in experimental tree shrews that received both hbv and afb1. it was significantly higher than that of animals exposed to hbv (11.1%, group b), or (afb1 ... | 1999 | 10374027 |
| mapping of cytoskeletal components in the hippocampal formation of the tree shrew (tupaia belangeri). | the distribution of the major cytoskeletal components in frontal cryosections of the hippocampal formation of adult male tree shrews (tupaia belangeri) was immunohistochemically investigated by using commercially available antibodies. actin-immunolabeling was evident in all layers of the dentate gyrus as well as in the regio superior (ca1) and the regio inferior (ca3). neurofilament 160 was detected only in the molecular layer of the dentate gyrus and in the axons of the granule cells (mossy fib ... | 1999 | 10585159 |
| defining the ancestral karyotype of all primates by multidirectional chromosome painting between tree shrews, lemurs and humans. | we used multidirectional chromosome painting with probes derived by bivariate fluorescence-activated flow sorting of chromosomes from human, black lemur (eulemur macaco macaco) and tree shrew (tupaia belangeri, order scandentia) to better define the karyological relationship of tree shrews and primates. an assumed close relationship between tree shrews and primates also assists in the reconstruction of the ancestral primate karyotype taking the tree shrew as an "outgroup" species. the results in ... | 1999 | 10591999 |
| the patterns of cell death and of macrophages in the developing forebrain of the tree shrew tupaia belangeri. | the patterns of cell death and of macrophages were investigated in the forebrain and eyes of the tree shrew tupaia belangeri during five phases of optic cup formation. seventeen embryos were studied. three- dimensional reconstructions were made from one embryo of each phase. in phase 1 (v-shaped optic evagination) a midline band of cell death passes through the closing anterior neuroporus. from phases 2 (optic vesicle) to 5 (far-advanced invagination) the midline band of cell death extends in th ... | 2000 | 10664177 |
| "rodent-like" and "primate-like" types of astroglial architecture in the adult cerebral cortex of mammals: a comparative study. | previous observations disclosed that astroglia with interlaminar processes were present in the cerebral cortex of adult new and old world monkeys, but not in the rat, and scarcely in the prosimian microcebus murinus. the present report is a more systematic and comprehensive comparative analysis of the occurrence of such processes in the cerebral cortex of several mammalian species. brain samples were obtained from adult individuals from the following orders: carnivora (canine), rodentia (rat and ... | 2000 | 10672363 |
| dendritic organization of neurons of the superior colliculus in animals with different visual capability. | the aim of the study was to compare several morphological characteristics of neurons in the superficial layers of the superior colliculus in diurnal and nocturnal mammals with different visual specialization. thus, we investigated the rat (rattus norvegicus), a nocturnal animal; the tree shrew (tupaia glis), a diurnal animal, and the mongolian rodents, microtus brandti (nocturnal) and alticola barakshin (diurnal). the investigation was focused on the study of the organization and extent of dendr ... | 2000 | 10718518 |
| reduction of aflatoxin b(1) adduct biomarkers by oltipraz in the tree shrew (tupaia belangeri chinensis). | the risk of liver cancer is greatest in people both infected with hepatitis b virus (hbv) and highly exposed to aflatoxin b(1) (afb(1)). the tree shrew (tupaia belangeri chinensis) is a unique species that can be infected with human hbv, is susceptible to afb(1)-induced liver cancer, and shows a synergistic interaction between hbv and afb(1) for liver cancer. in this regard, the tree shrew may be useful for evaluating experimental chemoprevention strategies relevant to high-risk human population ... | 2000 | 10799742 |
| occurrence of orientia tsutsugamushi in chiggers (acari: trombiculidae) and small animals in an orchard near bangkok, thailand. | the ecology of orientia tsutsugamushi (hayashi) was studied in chiggers and small animals in an orchard near bangkok, thailand. small animals were trapped monthly between july and november 1992 and examined for the presence of o. tsutsugamushi and ectoparasitic chiggers. a total of 40 rattus rattus (l.) and 16 tupaia glis (diard) was trapped. o. tsutsugamushi was isolated from liver and spleen samples of 30.8% of r. rattus and 18.6% of t. glis. antibodies to o. tsutsugamushi were detected in 95% ... | 1999 | 10467771 |
| geographical variation of the skull morphology of the common tree shrew (tupaia glis). | geographical variation was examined morphologically in the common tree shrew (tupaia glis) in some indochinese and malayan regions. osteometrical examination and principal component analysis elucidated the morphological differences among various populations. the populations from southern and western thailand were distinguished morphologically from the other populations. variation in males from south thailand and kuala lumpur suggests that the isthmus of kra may have an influence on the variation ... | 1999 | 10535508 |
| localization of dopamine receptors in the tree shrew brain using [3h]-sch23390 and [125i]-epidepride. | the tree shrew is a mammalian species, which is phylogenetically related to insectivores and primates. the aim of the present study was to investigate the distribution of dopamine receptor d1- and d2-like binding sites in the brain of this non-rodent, non-primate mammal. using in vitro autoradiography and employing the radioligands [3h]-sch23390 and [125i]-epidepride, dopamine receptors were mapped and quantified. significant findings with regard to the d1-like binding pattern include the presen ... | 1999 | 10546993 |
| coexistence of linear zones and pinwheels within orientation maps in cat visual cortex. | revealing the layout of cortical maps is important both for understanding the processes involved in their development and for uncovering the mechanisms underlying neural computation. the typical organization of orientation maps in the cat visual cortex is radial; complete orientation cycles are mapped around orientation singularities. in contrast, long linear zones of orientation representation have been detected in the primary visual cortex of the tree shrew. in this study, we searched for the ... | 2000 | 10805812 |
| multivariate analysis in skull osteometry of the common tree shrew from both sides of the isthmus of kra in southern thailand. | the isthmus of kra in southern thailand consists of a lowland of about 70 km in length. it has been suggested that the isthmus may sink beneath the sea surface according to the change of level of the sea, and may function as a zoogeographical barrier in land mammals in this region. so, the geographical variation was osteometrically examined in skull of the common tree shrew (tupaia glis) from the both sides of isthmus of kra. the osteometrical examination demonstrated that the skull is larger in ... | 2000 | 10823723 |
| mutations in the p53 tumor suppressor gene in tree shrew hepatocellular carcinoma associated with hepatitis b virus infection and intake of aflatoxin b1. | infection with hepadnaviruses and exposure to aflatoxin b1 (afb1) are considered to be major risk factors in the development of hepatocellular carcinoma (hcc) in humans. a high rate of p53 mutations at codon 249 has been reported in these tumors. the tree shrew (tupaia belangeri chinensis) is a useful animal model for the development of hcc after human hepatitis b virus (hbv) infection or afb1 treatment. therefore, it was of particular interest to determine whether the p53 gene in tree shrew hcc ... | 2000 | 10863098 |
| induced myopia associated with increased scleral creep in chick and tree shrew eyes. | to investigate the role of scleral creep in the axial elongation of chick and tree shrew eyes with induced myopia. | 2000 | 10892839 |
| cerebral microvascular architecture in the common tree shrew (tupaia glis) revealed by plastic corrosion casts. | the vascularization of the cerebrum (cerebral cortex and basal ganglia) in the common tree shrew (tupaia glis) has been studied in detail using vinyl injection and vascular corrosion cast/sem techniques. it is found that the arterial supply of the cerebral cortex are from cortical branches of the middle cerebral artery (mca) and of the anterior cerebral artery (aca). these arteries are in turn branches of the internal carotid artery (ica). in addition, the cerebral cortex receives the blood from ... | 2000 | 10941177 |
| sympatric distribution of the two morphological types of the common tree shrew in hat-yai districts (south thailand). | the two color types (grayish northern and reddish southern types) of the common tree shrew (tupaia glis and tupaia belangeri) were co-distributed in hat-yai region (south thailand). although the isthmus of kra in south thailand has been considered as distribution barrier of the two types, the sympatric distribution of both types was confirmed in southern side of the isthmus. in the principal component analysis, the skull measurement character from hat-yai region could also be separated into the ... | 2000 | 10945296 |
| regulation of alpha(2a)-adrenoceptor expression by chronic stress in neurons of the brain stem. | alpha(2)-adrenoceptors are supposed to be important regulatory elements in responses to stress. previous receptor binding studies in male tree shrews have shown that chronic psychosocial stress down-regulates binding sites for alpha(2)-adrenergic ligands in several brain stem nuclei. the aim of the present study was to quantify effects of chronic subordination stress on expression of the alpha(2)-adrenoceptor subtype a gene in identified neurons of the brain stem. we partially cloned the alpha(2 ... | 2000 | 11032999 |
| central gabaergic innervation of the mammalian pineal gland: a light and electron microscopic immunocytochemical investigation in rodent and nonrodent species. | light and electron microscopic immunocytochemical observations were made to demonstrate central pinealopetal fibers immunoreactive for gamma-aminobutyric acid (gaba) and synapses between their terminals and pinealocytes in the pineal gland of four rodent (wistar-king rat; mouse; syrian hamster, mesocricetus auratus; hartley strain guinea pig) and one nonrodent (tree shrew, tupaia glis) species. gaba-immunoreactive myelinated and unmyelinated fibers and endings were found in the parenchyma of the ... | 2001 | 11135246 |
| hepatitis b virus (hbv) virion and covalently closed circular dna formation in primary tupaia hepatocytes and human hepatoma cell lines upon hbv genome transduction with replication-defective adenovirus vectors. | hepatitis b virus (hbv), the causative agent of b-type hepatitis in humans, is a hepatotropic dna-containing virus that replicates via reverse transcription. because of its narrow host range, there is as yet no practical small-animal system for hbv infection. the hosts of the few related animal viruses, including woodchuck hepatitis b virus and duck hepatitis b virus, are either difficult to keep or only distantly related to humans. some evidence suggests that tree shrews (tupaias) may be suscep ... | 2001 | 11152483 |
| molecular phylogenetics and the origins of placental mammals. | the precise hierarchy of ancient divergence events that led to the present assemblage of modern placental mammals has been an area of controversy among morphologists, palaeontologists and molecular evolutionists. here we address the potential weaknesses of limited character and taxon sampling in a comprehensive molecular phylogenetic analysis of 64 species sampled across all extant orders of placental mammals. we examined sequence variation in 18 homologous gene segments (including nearly 10,000 ... | 2001 | 11214319 |
| structural organization and analysis of the viral terminase gene locus of tupaia herpesvirus. | tupaia herpesvirus (thv) was isolated from spontaneously degenerating tissue cultures of malignant lymphoma, lung, and spleen cell cultures of tree shrews (tupaia spp.). in order to determine the phylogenetic relatedness of thv the complete nucleotide sequence of the viral terminase (vter) gene locus (6223 bp) of tupaia herpesvirus strain 2 (thv-2) was elucidated and analysed. the vter gene locus, encoding one of the most highly conserved herpes viral proteins is composed of two exons. the intro ... | 2001 | 11226571 |
| animal models of myopia: learning how vision controls the size of the eye. | as they grow up, approximately 25% of children in the united states become myopic (nearsighted). a much smaller fraction become significantly hyperopic (farsighted), while the majority develop little or no refractive error and are emmetropic. the causes of refractive error, especially myopia, have been the subject of debate for more than a century. some have held that myopia is primarily an inherited disorder, and others, that myopia is caused by protracted near work and, especially, by accommod ... | 1999 | 11304585 |
| analysis and characterization of the complete genome of tupaia (tree shrew) herpesvirus. | the tupaia herpesvirus (thv) was isolated from spontaneously degenerating tissue cultures of malignant lymphoma, lung, and spleen cell cultures of tree shrews (tupaia spp.). the determination of the complete nucleotide sequence of the thv strain 2 genome resulted in a 195,857-bp-long, linear dna molecule with a g+c content of 66.5%. the terminal regions of the thv genome and the loci of conserved viral genes were found to be g+c richer. furthermore, no large repetitive dna sequences could be ide ... | 2001 | 11312357 |
| cold adaptive thermogenesis in small mammals from different geographical zones of china. | the mechanisms of thermogenesis and thermoregulation were studied in the tree shrew (tupaia belangeri) and greater vole (eothenomys miletus) of the subtropical region, and brandt's vole (microtus brandti), mongolian gerbil (meriones unguiculatus), daurian ground squirrel (spermophilus dauricus) and plateau pika (ochotona curzoniae) of the northern temperate zone. resting metabolic rate (rmr) and non-shivering thermogenesis (nst) increased significantly in t. belangeri, e. miletus, m. brandti and ... | 2001 | 11440879 |
| stress-induced changes in cerebral metabolites, hippocampal volume, and cell proliferation are prevented by antidepressant treatment with tianeptine. | stress-induced structural remodeling in the adult hippocampus, involving debranching and shortening of dendrites and suppression of neurogenesis, provides a cellular basis for understanding the impairment of neural plasticity in the human hippocampus in depressive illness. accordingly, reversal of structural remodeling may be a desirable goal for antidepressant therapy. the present study investigated the effect of tianeptine, a modified tricyclic antidepressant, in the chronic psychosocial stres ... | 2001 | 11675510 |
| [clone and tissue expression of tree shrew apolipoprotein ai cdna]. | to clone apolipoprotein ai (apoai) gene from tree shrew (ts) which is an animal insusceptible to atherosclerosis and to analyze the characteristics of the gene. | 1999 | 11715479 |
| adrenal glands in small smooth-tailed tree shrew (dendrogale murina). | adrenal glands of small smooth-tailed tree shrews (dendrogale murina), four males and two females, caught and fixed in thailand were observed macroscopically and histologically. they were located at the cranio-medial sides of the kidney. they were elongated in shape and consisted of a cortex and medulla. the cortex could be subdivided into three zones by the cell arrangement and the morphology of nuclei, cytoplasm and cell strands, like in other mammalian species. the tree shrew seemed to share ... | 2001 | 11769551 |
| primary hepatocytes of tupaia belangeri as a potential model for hepatitis c virus infection. | hepatitis c virus (hcv) is a major cause of chronic hepatitis worldwide, but the study of hcv infection has been hampered by the lack of an in vitro or in vivo small animal model. the tree shrew tupaia belangeri is susceptible to infection with a variety of human viruses in vivo, including hepatitis viruses. we show that primary tupaia hepatocytes can be infected with serum- or plasma-derived hcv from infected humans, as measured by de novo synthesis of hcv rna, analysis of viral quasispecies ev ... | 2002 | 11805134 |
| effects of brief periods of unrestricted vision on the development of form-deprivation myopia in monkeys. | to characterize the temporal integration properties of the mechanisms responsible for form-deprivation myopia (fdm), the effects of brief daily periods of unrestricted vision on the degree of fdm were investigated in infant monkeys. | 2002 | 11818369 |
| how tree shrews (tupaia belangeri) perform in a searching task: evidence for strategy use. | this study investigated how male tree shrews (tupaia belangen) performed in a searching task while in their home cages and assessed whether different food distributions affected their performance. the animals were faced with a holeboard containing 9 food sources arranged in a 3 x 3 matrix or in 3 clusters, each containing 3 sources. animals tended to start and end the trials from preferred locations, thereafter solving the task by strategically organizing the reward collection according to a min ... | 2001 | 11824897 |
| retinal acetylcholine content in normal and myopic eyes: a role in ocular growth control? | retinal neurotransmitters are known to play a role in postnatal ocular development and eye growth. the success of muscarinic antagonists in blocking form-deprivation myopia has implicated retinal acetylcholine in the control of ocular growth. the present study investigated whether steady-state content of acetylcholine (ach) and its metabolite choline (ch) are altered in the retina of eyes developing axial myopia, in both tree shrews and chicks. retinal ach and ch content were measured using reve ... | 2001 | 11829303 |
| ovulation in the tree shrew (tupaia belangeri) induced by gonadotrophins. | the induction of ovulation by exogenous gonadotrophins is an important approach for recovering oocytes used for studies on the reproductive biology of some mammals. in the present study, pregnant mare serum gonadotrophin (pmsg) and human chorionic gonadotrophin (hcg) were used to induce ovulation in the tree shrew (tupaia belangeri) using the following regimens. groups a1-a3, multiple injections of pmsg (30-60 iu) followed by a single dose of hcg (30-60 iu); b1, combination of a single injection ... | 2001 | 11833933 |
| chromosome painting reveals that galagos have highly derived karyotypes. | the differences in chromosome number between otolemur crassicaudatus (2n = 62) and galago moholi (2n = 38) are dramatic. however, the total number of signals given by hybridizing human chromosome paints to galago metaphases is similar: 42 in o. crassicaudatus and 38 g. moholi. many human chromosome homologs are found fragmented in each species, and numerous translocations have resulted in chromosomal syntenies or hybridization associations which differ from those found in humans. only 7 human au ... | 2002 | 11920367 |
| torque patterns of the limbs of small therian mammals during locomotion on flat ground. | in three species of small therian mammals (scandentia: tupaia glis, rodentia: galea musteloides and lagomorpha: ochotona rufescens) the net joint forces and torques acting during stance phase in the four kinematically relevant joints of the forelimbs (scapular pivot, shoulder joint, elbow joint, wrist joint) and the hindlimbs (hip joint, knee joint, ankle joint, intratarsal joint) were determined by inverse dynamic analysis. kinematics were measured by cineradiography (150 frames s(-1)). synchro ... | 2002 | 11948209 |
| analysis of distributions of amino acids in the primary structure of tumor suppressor p53 family according to the random mechanism. | it is well known that the evolutionary process leads to the majority of amino acids clustering in some regions rather than being homogenously distributed along a protein. among numerous factors affecting the evolutionary process is chance, whose impact therefore should be present in a protein primary structure. the issue of how to measure the random distribution of amino acids in a primary structure is of importance for the understanding of protein structure and functions. in this study, we use ... | 2002 | 12111387 |
| a comparative study on the cortico-hypoglossal connections in primates, using biotin dextranamine. | the anterograde projections of the motorcortical tongue area to the hypoglossal nucleus and neighbouring structures were studied in the rhesus monkey, squirrel monkey, saddle-back tamarin and tree shrew. biotin dextranamine served as tracer. direct projections into the hypoglossal nucleus were only found in the rhesus monkey and squirrel monkey. all four species, however, showed a direct projection into the dorsal and parvocellular reticular formation which in turn projects into the hypoglossal ... | 2002 | 12147317 |
| the cdna sequence and its tissue expression of tree shrew apolipoprotein ci. | the mrna was isolated and purified from tree shrew (ts) liver tissue. a cdna library of the liver tissue was then constructed by using the mrna as the template by reverse transcription. two apolipoprotein ci (apoci) cdna clones were identified in the library with an anti-serum to ts apoci. sequencing and analysizing of the clones showed that both were the apoci cdna sequences in which the larger one was determined as 380 nucleotides. it contains 21 bp and 95 bp in 5' and 3' untranslated regions ... | 1998 | 12174255 |
| cytogenetic differentiation of two sympatric tree shrew taxa found in the southern part of the isthmus of kra. | sympatric populations of the genus tupaia encompassing two cytotypes (cyt60, 2n = 60 and cyt62, 2n = 62) were found in the southern part of the isthmus of kra (the middle region of the malay peninsula, thailand). c-bands, location of rdna, and location of non-essential telomeric repeats (trs) were investigated in detail for 23 animals captured in the area. such chromosomal traits definitely reveal that two distinct cytotypes exist in the sympatric population, though the external morphological tr ... | 2002 | 12199145 |
| convergences in the modular and areal organization of the forebrain of mammals: implications for the reconstruction of forebrain evolution. | early efforts to reconstruct the course of the evolution of the human brain relied on comparing the brains of a few related mammals with brains at successively higher levels of complexity. this clark or ladder of levels approach is now seen as having limited usefulness in that species are not easily assigned to levels, and extant mammals are now recognized as mosaics of primitive and derived features. in addition, direction of change does not necessarily proceed from simple to complex, small to ... | 2002 | 12207083 |
| pika and vole mitochondrial genomes increase support for both rodent monophyly and glires. | complete mitochondrial genomes are reported for a pika (ochotona collaris) and a vole (volemys kikuchii) then analysed together with 35 other mitochondrial genomes from mammals. with standard phylogenetic methods the pika joins with the other lagomorph (rabbit) and the vole with the other murid rodents (rat and mouse). in addition, with hedgehog excluded, the seven rodent genomes consistently form a homogeneous group in the unrooted placental tree. except for uncertainty of the position of tree ... | 2002 | 12234673 |
| efficient infection of primary tupaia hepatocytes with purified human and woolly monkey hepatitis b virus. | the asian tree shrew, tupaia belangeri, has been proposed as a novel animal model for studying hepatitis b virus (hbv) infection. here, we describe a protocol for efficient and reproducible infection of primary tupaia hepatocytes with hbv. we report that human serum interferes with hbv binding to the hepatocytes, thus limiting the maximum multiplicity of infection. purification of hbv virions by gradient sedimentation greatly enhances virus binding and infectivity. covalently closed circular dna ... | 2001 | 11333889 |
| marsupials and eutherians reunited: genetic evidence for the theria hypothesis of mammalian evolution. | the three living monophyletic divisions of class mammalia are the prototheria (monotremes), metatheria (marsupials), and eutheria ('placental' mammals). determining the sister relationships among these three groups is the most fundamental question in mammalian evolution. phylogenetic comparison of these mammals by either anatomy or mitochondrial dna has resulted in two conflicting hypotheses, theria and marsupionta, and has fueled a "genes versus morphology" controversy. we have cloned and analy ... | 2001 | 11420613 |
| psychosocial stress, glucocorticoids, and structural alterations in the tree shrew hippocampus. | animal models for chronic stress represent an indispensable preclinical approach to human pathology since clinical data point to a major role of psychological stress experiences, acute and/or chronic, to the development of behavioral and physiological disturbances. chronic emotional arousal is a consequence of various types of social interactions, and one major neurohumoral accompaniment is the activation of the classic stress circuit, the limbic--hypothalamic--pituitary--adrenocortical (lhpa) a ... | 2001 | 11438353 |
| the tree shrews: adjuncts and alternatives to primates as models for biomedical research. | the tree shrews are non-rodent, primate-like, small animals. there is increasing interest in using them to establish animal models for medical and biological research. this review focuses on the use of the tree shrews in in vivo studies on viral hepatitis, hepatocellular carcinoma (hcc), myopia, and psychosocial stress. because of the susceptibility of the tree shrews (tupaia belangeri) and their hepatocytes to infection with human hepatitis b virus (hbv) in vivo and in vitro, these animals have ... | 2003 | 12823622 |
| nonvascular smooth muscle alpha-actin positive cells in the choroid of higher primates. | as an elaborated network of non-vascular smooth muscle alpha-actin positive cells (nvsmc) is present in the human eye, the purpose of this investigation was to describe the presence of nvsmc in the sclera and choroid of different mammals and primates. | 2003 | 12868003 |
| cloning and characterization of cholesteryl ester transfer transfer protein isolated from the tree shrew. | to obtain the nucleotide sequence and deduced amino acid sequence of cholesteryl ester transfer protein (cetp) cdna from the tree shrew (tupaia glis). | 2003 | 12877809 |
| [human hepatitis b virus infection of tree shrews and macaca assamensis in vivo]. | to examine sensitivity of the tree shrews and macaca assamensis to human hepatitis b virus (hhbv) by serologic methods. | 2003 | 12884835 |
| unique mammalian trna-derived repetitive elements in dermopterans: the t-sine family and its retrotransposition through multiple sources. | short interspersed nuclear elements (sines) are dispersed repetitive dna sequences that are major components of all mammalian genomes. they have been described in almost all lineages of euarchontoglires (rodents, rabbits, primates, flying lemurs, and tree shrews), except in flying lemurs. most sine family members are composed of three distinct regions: a 5' trna-related region, a trna-unrelated region, and a short tandem repeat at the 3' end that is at-rich. the newly discovered sine family in c ... | 2003 | 12885966 |
| regulation of slo potassium channel alternative splicing in the pituitary by gonadal testosterone. | slo gene-encoded bk potassium channels are prominent in both adrenomedullary and pituitary tissues. at one alternative splicing site, both tissues express variants with and without the optional 'strex' exon. in adrenal chromaffin cells, this splicing choice, which has important ramifications for cell excitability, has been shown to be regulated by steroid hormones, including glucocorticoids and adrenal androgens. moreover, striking sex differences are seen between male and female tree shrews. he ... | 2004 | 15049854 |
| the tree shrew apolipoprotein c-i cdna: sequence and its expression. | a rabbit anti-serum to tree shrew apolipoprotein c-i (apo c-i) was used to screen an expression cdna library constructed by us from tree shrew (ts) liver tissue. two apo c-i cdna clones were obtained. the longer one consists of 380 nucleotides, including 21 bp and 95 bp at the 5' and 3' end of the non-translated regions respectively, and a 264-bp fragment in an open reading frame encoding 88 amino acids prepropeptide which contains 26 amino acids of signal peptide and a mature protein (62 amino ... | 2001 | 12903754 |
| [analysis of lecithin-cholesterol acyltransferase cdna and protein sequence from tree shrew]. | to acquire cdna sequence of lecithin-cholesterol acyltransferase (lcat) from tree shrew and analyze the sequence structure. | 2002 | 12905792 |
| molecular anatomy of tupaia (tree shrew) adenovirus genome; evolution of viral genes and viral phylogeny. | adenoviruses are globally spread and infect species in all five taxons of vertebrates. outstanding attention is focused on adenoviruses because of their transformation potential, their possible usability as vectors in gene therapy and their applicability in studies dealing with, e.g. cell cycle control, dna replication, transcription, splicing, virus-host interactions, apoptosis, and viral evolution. the accumulation of genetic data provides the basis for the increase of our knowledge about aden ... | 2003 | 12913356 |
| purkinje-like cells in the cochlear nucleus of the common tree shrew (tupaia glis) identified by calbindin immunohistochemistry. | the dorsal cochlear nucleus (dcn) of tree shrews (tupaia glis; n=2) was examined by calbindin (cb) immunohistochemistry for the presence of purkinje-like cells (plcs), detected previously in only four different mammals. we found up to eight cb-immunoreactive plcs in the left and right dcn, and a few axons, likely of plc origin, that appeared to leave the dcn. these findings suggest that plcs may have a wider distribution through mammalian species, and may represent more than just misrouted cells ... | 2003 | 12914985 |
| pre-s1 antigen-dependent infection of tupaia hepatocyte cultures with human hepatitis b virus. | the susceptibility of the tree shrew tupaia belangeri to human hepatitis b virus (hbv) has been demonstrated both in vivo and in vitro. in this study, we show that purified hbv infects primary t. belangeri hepatocyte cultures in a very specific manner, as detected by hbv covalently closed circular dna, mrna, hbv e antigen, and hbsag production. a monoclonal antibody (mab), ma18/7, directed against the pre-s1 domain of the large hbs protein, which has been shown to neutralize infectivity of hbv f ... | 2003 | 12915565 |
| protection of tree shrews by pvax-ps dna vaccine against hbv infection. | the immunological protection of pvax-ps, a dna vaccine, was assessed in the tree shrews model. pvax-ps was constructed by inserting the gene encoding the middle (pre-s2 plus s) envelope protein of hbv into a plasmid vector pvax1. tree shrews (tupaia belangeri chinenesis) were experimentally infected with human hbv by inoculation with human serum positive for hbv markers. dna vaccination-induced seroconversion and antibody to hbv surface antigen (anti-hbs) were analyzed by elisa, and protective e ... | 2003 | 12932306 |
| expression and cdna sequence of matrix metalloproteinase-2 (mmp-2) in a mammalian model of human disease processes: tupaia belangeri. | matrix metalloproteinase-2 (mmp-2) is one of a family of proteolytic enzymes that are involved in the remodelling of tissue during normal growth processes and is capable of degrading structural components of the extracellular matrix. increases in mmp-2 expression and activity have been reported in diseases that involve degradation of the extracellular matrix. reported here for the first time are the relative levels of expression of mmp-2 in tissues of the tree shrew along with 2587 bases of the ... | 2004 | 15621657 |
| morphological adaptation of the skull for various behaviors in the tree shrews. | skull size and shape were examined among 14 species of the tree shrews (tupaia montana, t. picta, t. splendidula, t. mulleri, t. longipes, t. glis, t. javanica, t. minor, t. gracilis, t. dorsalis, t. tana, dendrogale melanura, d. murina, and ptilocercus lowii). the bones of face were rostro-caudally longer in t. tana and t. dorsalis, contrasting with t. minor and t. gracilis, d. melanura, d. murina and p. lowii which have smaller facial length ratios. the arbo-terrestrial species (t. longipes an ... | 2003 | 12951419 |
| identification of aflatoxin m1-n7-guanine in liver and urine of tree shrews and rats following administration of aflatoxin b1. | epidemiological studies have shown that exposure to aflatoxin b(1) (afb(1)) and concurrent infection with hepatitis b lead to a multiplicative risk of developing liver cancer. this chemical-viral interaction can be recapitulated in the tree shrew (tupia belangeri chinensis). as an initial characterization of this model, the metabolism of afb(1) in tree shrews has been examined and compared to a sensitive bioassay species, the rat. utilizing lc/ms/ms, an unreported product, aflatoxin m(1)-n(7)-gu ... | 2003 | 12971806 |
| [differentially expressed genes in hepatocellular carcinoma of tree shrew induced by different factors]. | previous studies on differentially expressed genes in hepatocellular carcinoma (hcc) used to perform with para-cancerous tissues as normal control. however, the para-cancerous tissue of hcc is actually abnormal because they frequently contain hepatitis, cirrhosis, hyperplastic nodules or foci, etc. in order to explore the molecular mechanism and the responsible genes for hepatocarcinogenesis, through applying the hcc model of tree shrew (tupaia belangeri chinensis), this study was designed to co ... | 2003 | 14558942 |
| the visual pulvinar in tree shrews i. multiple subdivisions revealed through acetylcholinesterase and cat-301 chemoarchitecture. | tree shrews are highly visual mammals closely related to primates. they have a large visual pulvinar complex, but its organization and relation to visual cortex is only partly known. we processed brain sections through the pulvinar with seven different procedures in an effort to reveal histologically distinct compartments. the results revealed three major subdivisions. a dorsal subdivision, pd, stains darkly for acetylcholinesterase (ache) and occupies the dorsoposterior one-third of the pulvina ... | 2003 | 14624491 |
| the visual pulvinar in tree shrews ii. projections of four nuclei to areas of visual cortex. | patterns of thalamocortical connections were related to architectonically defined subdivisions of the pulvinar complex and the dorsolateral geniculate nucleus (lgn) in tree shrews (tupaia belangeri). tree shrews are of special interest because they are considered close relatives of primates, and they have a highly developed visual system. several distinguishable tracers were injected within and across cortical visual areas in individual tree shrews in order to reveal retinotopic patterns and cor ... | 2003 | 14624492 |
| subordination stress alters alternative splicing of the slo gene in tree shrew adrenals. | it was previously hypothesized that stress hormones regulate the alternative splicing of slo potassium channels, thereby tuning the intrinsic excitability of adrenal chromaffin cells. male tree shrews subjected to chronic stress by exposure to a dominant male develop robust symptoms with parallels to human depression. we report here that adrenals from males subjected to 4-6 weeks of subordination have a significantly smaller proportion of slo transcripts with the optional strex exon (stress-axis ... | 2003 | 12614648 |
| characterization of the complete genome of the tupaia (tree shrew) adenovirus. | the members of the family adenoviridae are widely spread among vertebrate host species and normally cause acute but innocuous infections. special attention is focused on adenoviruses because of their ability to transform host cells, their possible application in vector technology, and their phylogeny. the primary structure of the genome of tupaia adenovirus (tav), which infects tupaia spp. (tree shrew) was determined. tree shrews are taxonomically assumed to be at the base of the phylogenetic tr ... | 2003 | 12634391 |
| [alteration of p53 gene during tree shrews' hepatocarcinogenesis]. | to detect the expression and variation of p53 gene during tree shrews' hepatocarcinogenesis induced by hepatitis b virus (hbv) and aflatoxin b1 (afb1). | 2003 | 12681064 |
| a mechanistic inter-species comparison of flicker sensitivity. | the general validity of both the rovamo [vision res. 39 (1999) 533] and barten (contrast sensitivity of the human eye, spie optical engineering press, 1999), modulation transfer function models for describing flicker sensitivity in vertebrates was examined using published data for goldfish, chickens, tree shrews, ground squirrels, cats, pigeons and humans. both models adequately described the flicker response in each species at frequencies greater than approximately 1 hz. at lower frequencies, r ... | 2003 | 12818343 |
| pattern of retinal projections in the california ground squirrel (spermophilus beecheyi): anterograde tracing study using cholera toxin. | the retinofugal pathways in the california ground squirrel, spermophilus beecheyi, were mapped after intravitreal injections of cholera toxin b-subunit. the results of the current study are consistent with work in other mammals and provide new details relevant to the organization and evolution of the visual system. all retinorecipient nuclei received bilateral input, with a contralateral predominance. the suprachiasmatic nucleus is heavily innervated, and sparse terminals were noted in other hyp ... | 2003 | 12820165 |