Publications

the effect of enzyme replacement on red cell adenine deoxyribonucleotides in adenosine deaminase-deficient erythrocytes of the opossum, didelphis virginiana.	1. polyethyleneglycol-modified bovine adenosine deaminase was administered (10-20 u/kg/week) intramuscularly to two opossums for 15 weeks and changes in red cell adenine ribo- and deoxyribonucleotides quantitated by hplc. 2. only a moderate decline of erythrocyte daxp was observed at the end of the study when compared to results of enzyme replacement seen in human adenosine deaminase deficient patients. 3. opossum red cells salvage substantial amounts of deoxyadenosine provided in physiologic (5 ...	1993	8281757
2'-deoxyadenosine metabolism in human and opossum didelphis virginiana erythrocytes in vitro.	1. in erythrocytes of both species, deamination and phosphorylation of dado was completely inhibited by 5 microm 2'deoxycoformycin and 10 microm 5-itu respectively. 2. under physiologic conditions, provided with nanomolar concentrations of dado there was complete deamination of dado in human red cells. in opossum erythrocytes deamination and phosphorylation of the deoxynucleoside were nearly; additionally, 1-2% of the substrate was metabolized to axp. 3. with ada inhibited in intact red cells, a ...	1993	8281758
development of the eye in the north american opossum (didelphis virginiana).	marsupials are unique models for developmental biology-oriented research because of the immature state of their development at birth. the north american opossum (didelphis virginiana) has several advantages over other marsupials, including large litter size, short prenatal period (12.5 d), an extended postnatal period while accessible in the pouch, and its ability to reproduce reliably in captivity. studies of ocular development in this species have not been reported previously. the aim of the p ...	1993	8300421
characterization of mannose 6-phosphate receptors (mprs) from opossum liver: opossum cation-independent mpr binds insulin-like growth factor-ii.	bovine, human, and rat cation-independent mannose 6-phosphate receptors (ci-mprs) are capable of binding both mannose 6-phosphate and insulin-like growth factor-ii (igf-ii). however, the receptor isolated from either chicken or frog lacks the high affinity igf-ii-binding site. to determine whether ci-mprs isolated from a species that is closely related to placental mammals can bind igf-ii, the mprs were purified from a marsupial, the american opossum (didelphis virginiana), by phosphomannan-seph ...	1993	8344189
characterization of a marsupial sperm protamine gene and its transcripts from the north american opossum (didelphis marsupialis).	a synthetic oligonucleotide primer, designed from marsupial protamine protein-sequence data [balhorn, r., corzett, m., matrimas, j. a., cummins, j. & faden, b. (1989) analysis of protamines isolated from two marsupials, the ring-tailed wallaby and gray short-tailed opossum, j. cell. biol. 107] was used to amplify, via the polymerase chain reaction, protamine sequences from a north american opossum (didelphis marsupialis) cdna. using the amplified sequences as probes, several protamine cdna clone ...	1993	8344286
opossum serum alpha 1-proteinase inhibitor: purification, linear sequence, and resistance to inactivation by rattlesnake venom metalloproteinases.	opossum (didelphis virginiana) serum was fractionated with (nh4)2so4 and then chromatographed on deae-sepharose and phenyl-sepharose. affinity chromatography on a protein a-sepharose-antibody column removed traces of opossum serum metalloproteinase inhibitors, and resulted in a homogeneous preparation of opossum alpha 1-proteinase inhibitor (alpha 1-pi). the inhibitor is a single-chain glycoprotein (17.7% carbohydrate) with an estimated m(r) = 54,000. an opossum liver cdna library was immunoscre ...	1993	8422360
parasitic arthropods of sympatric opossums, cotton rats, and cotton mice from merritt island, florida.	six species of parasitic arthropods were collected from 12 opossums (didelphis virginiana), 8 species were obtained from 28 cotton rats (sigmodon hispidus), and 4 species were collected from 10 cotton mice (peromyscus gossypinus) from merritt island, brevard county, florida. the flea polygenis gwyni was the only parasite that infested all 3 host species, and it was present in very high densities (mean intensity = 73.7) on the opossums. the american dog tick, dermacentor variabilis, and the tropi ...	1993	8459341
the development of myelin in the spinal cord of the north american opossum and its possible role in loss of rubrospinal plasticity. a study using myelin basic protein and galactocerebroside immuno-histochemistry.	the aims of this study were to observe the timing and sequence of myelin formation in the opossum's spinal cord by using myelin basic protein (mbp) immuno-histochemistry and to determine whether the onset of myelination, as demonstrated by the presence of mbp or galactocerebroside (galc)-like immuno-reactivity (li), correlates temporally with the end of the critical period for rubrospinal plasticity. rubral axons grow around a lesion of their pathway during early development but they do not do s ...	1993	7680969
release of nitric oxide by activation of nonadrenergic noncholinergic neurons of internal anal sphincter.	the purpose of the present study was to investigate the direct release of nitric oxide (no) in response to the stimulation of nonadrenergic noncholinergic (nanc) nerves. the studies were performed on isolated smooth muscle strips of the opossum (didelphis virginiana) internal anal sphincter (ias). electrical field stimulation (efs) using the appropriate parameters caused a frequency-dependent fall in the resting tone of the ias. the release of no was measured directly by the chemiluminescence me ...	1993	8430806
morphological observations on the unique paired capillaries of the opossum retina.	light-microscopic and ultrastructural analysis of the ocular tissues of the north american opossum (didelphis virginiana) revealed that the arterial and venous segments of retinal vessels, including capillaries of the smallest calibre, occur in pairs. they do not form anastomotic networks, the common pattern in mammals with vascularised retinae, but instead the two segments of the pair join to form hairpin end loops. the paired vessels, with the arteriolar limb usually on the vitread aspect, pen ...	1993	8472304
the origins of descending projections to the lumbar spinal cord at different stages of development in the north american opossum.	we have employed the retrograde transport of fast blue (fb) to identify the origins of descending projections to the lumbar cord of the opossum from postnatal day (pd)1, 12-13 days after conception, to maturity. when fb injections were made into the lumbar cord at pd1, supraspinal labeling was sparse and limited to the hypothalamus, the reticular formation, the coeruleus complex, the caudal raphe, and, in one case, the interstitial nucleus of the medial longitudinal fasciculus and the lateral ve ...	1993	8457879
maximum discharge rates of respiratory neurons during opossum development.	the observed low frequencies of action potentials observed in medullary respiratory neurons of immature opossums (didelphis virginiana) could occur because these cells are incapable of achieving higher sustained firing rates. nonsustainability of firing might also help explain why the inspired breath is brief (approximately 0.1 s) in the youngest opossums and rises very slowly during postnatal life. firing frequencies of medullary respiratory neurons were examined in spontaneously breathing thio ...	1993	8307857
development of an astrocytic response to lesions of the spinal cord in the north american opossum: an immunohistochemical study using anti-glial fibrillary acidic protein.	we have shown previously that rubral axons grow around a lesion of their pathway in developing opossums and that a critical period exists for that plasticity. the critical period begins when rubral axons first reach the level of the lesion and ends sometime between postnatal days (pd) 26 and 30. the aim of the present study was to examine the development of an astrocytic response to lesioning the spinal cord to determine if there is a temporal correlation between the development of such a respon ...	1993	8244527
development of radial glia and astrocytes in the spinal cord of the north american opossum (didelphis virginiana): an immunohistochemical study using anti-vimentin and anti-glial fibrillary acidic protein.	we have shown previously that rubrospinal axons grow around a lesion of their pathway in developing opossums and that a critical period exists for that plasticity. as a first step toward addressing the possibility that glial maturation and/or the development of an astrocytic response to lesioning contribute to loss of rubrospinal plasticity, we have studied the normal development of radial glia and astrocytes in the spinal cord of the opossum by immunostaining for vimentin (vim) and glial fibril ...	1993	8244526
gestation and placentation in two new world opossums: didelphis virginiana and monodelphis domestica.	estrus, gestation, and placentation were studied in the virginia opossum (didelphis virginiana) and the gray short-tailed oppossum (monodelphis domestica), representatives of the prototypic, new world marsupial family didelphidae. didelphis is a large (3,000 g), pouched opossum that exhibits a 28-day estrous cycle, spontaneous estrus and ovulation, and a high ovulation rate (60 ova per cycle). monodelphis is a small (100 g), pouchless opossum with male-induced estrus and ovulation and a moderate ...	1993	8371092
heavy metals in the hair of opossum from palo verde, costa rica.	levels of lead, cadmium, mercury, chromium, and manganese were measured in the hair of opossum (didelphis virginiana) from palo verde, guanacaste, costa rica. this area has some agriculture, but is slated for extensive water development that will increase ecosystem exposure to a variety of agricultural chemicals. metal levels were generally not intercorrelated except for chromium and lead, chromium and cadmium, and cadmium and lead. there were significant gender differences only for lead and chr ...	1994	7811107
brain growth and neocortical development in the opossum.	general brain growth and differentiation of the neocortex have been studied in the marsupial, didelphis virginiana from the 10.5 day embryo through adulthood. didelphis is born after a short gestation period of about 12.5 days, at a time when the telencephalic wall consists only of two layers and is considered to be at an embryonic stage of development. the cortical plate does not appear until late in the first postnatal week, thus neocortical development is totally a postnatal phenomenon in did ...	1994	7978336
hearing in primitive mammals: monodelphis domestica and marmosa elegans.	although opossums of the family didelphidae usually serve as a parsimonious starting point for tracing the otological and neurological evolution of modern mammals, audiological data for didelphid opossums is available only for the north american opossum (didelphis virginiana) which because of its large size, may be one of the least representative genera of the family. the present report extends the audiological data to two other species of didelphid opossums, monodelphis domestica, and marmosa e ...	1994	7928716
x-chromosome replication patterns in adult, newborn and prenatal opossums.	somatic cells from the opossums monodelphis domestica and didelphis virginiana were labelled with 5-bromodeoxyuridine (brdu), treated with colchicine, stained with acridine orange and examined using fluorescence microscopy. brdu-incorporated metaphase spreads from females of m. domestica at developmental stages from late bilaminar blastocysts to adults showed replication asynchrony of the two (acrocentric) x chromosomes. the long arm of one x chromosome was the latest replicating region in the e ...	1994	7878226
timetable of in vivo embryonic development in the grey short-tailed opossum (monodelphis domestica).	the timing of development was examined in 496 embryos from female monodelphis domestica collected at known time intervals after video recorded mating. ovulation occurred approximately 20 hr (day 1) after mating, and fertilization was observed by 24 hr. transport through the oviducts was rapid, and pronuclear stage embryos were recovered from the uterus as early as 24 hr after mating. second cleavage had occurred by 55 hr after mating. three-celled embryos were among those collected on day 3 afte ...	1994	7893485
colocalization of nadph-diaphorase activity and certain neuropeptides in the esophagus of opossum (didelphis virginiana).	nitric oxide and various neuropeptides in the myenteric plexus regulate esophageal motility. we sought colocalization of nitric oxide synthase and neuropeptides in frozen sections of mid-portion of smooth-muscled opossum esophagus using nadph-diaphorase activity to mark the synthase and immunoreactivity to detect peptides. the peptides, all with demonstrated physiological activity in this organ, were calcitonin gene-related peptide, galanin, neuropeptide y, substance p, and vasoactive intestinal ...	1994	7531620
developmental plasticity of reticulospinal and vestibulospinal axons in the north american opossum, didelphis virginiana.	we have shown previously that rubral axons grow around a lesion of their spinal pathway in the north american opossum if it is made at early stages of development. in the present experiments, we have asked whether reticular and vestibular axons have the same ability. the spinal cord was hemisected at postnatal day 20, 12, or 5, well within the critical period for rubrospinal plasticity, and, approximately 30 days later, bilateral injections of fast blue were made about four segments caudal to th ...	1994	7860784
early development of cerebellar afferent systems that contain corticotropin-releasing factor.	corticotropin-releasing factor (crf) and crf binding sites have been described in the cerebellum of several species, including the north american opossum (didelphis marsupialis virginiana), the species used in the present study. inotophoretic application of this peptide in the adult cerebellum enhances the spontaneous and amino acid-induced firing rate of purkinje cells and overcomes the gaba-induced suppression of purkinje cell activity. the present account provides immunohistochemical evidence ...	1994	7890829
distribution of cholecystokinin binding sites in the north american opossum cerebellum.	previous studies in our laboratory have reported on the differential distribution of several neuropeptides, including the octapeptide cholecystokinin (cck8), in the cerebellar cortex and nuclei of the north american opossum (didelphis marsupialis virginiana). the present account reports on the distribution of cck8 binding sites as determined from serial autoradiographic images of the cerebellum which were labelled by using [125i]bolton hunter sulfated cck8. evidence for the limited presence of c ...	1994	7802965
distribution of heat-stable enterotoxin/guanylin receptors in the intestinal tract of man and other mammals.	the human intestinal tract, as well as that of several eutherian and metatherian mammals, was examined for the distribution of heat-stable enterotoxin (st)/guanylin receptors. these receptors were confined to the intestinal epithelium lining the lumen and forming the intestinal glands throughout the length of both the small intestine and colon of all species examined. in man and most other mammalian species, there appeared to be a decrease in receptor density distally along the longitudinal axis ...	1994	8014132
experimental ureteral obstruction in the fetal opossum: histologic assessment.	in the north american opossum, didelphis virginiana unilateral complete ureteral obstruction (eco) and partial unilateral (epo) ureteral obstruction were created during the early metanephric stage of kidney development in pups attached to the teat (approximately 4.5 cm. long, 20 days old). at 70 days of pouch life (full-term equivalent in the human) some completely obstructed ureters were unobstructed with reanastomosis in the bladder (reco). other pups underwent unilateral complete ureteral lig ...	1994	7966702
projection of visuotopically organized afferents to the dorsal thalamus in the opossum, monodelphis domestica.	retrogradely transported dyes, fluorogold and fast blue were injected into both sides of the dorsal thalamus in the monodelphis opossum. projection of the presumed primary visual cortical area, superior colliculus and parabigeminal nucleus to the dorsal lateral geniculate nucleus and the lateral posterior--lateral intermedius nuclear complex were described. they show close similarities to the homologous projections in the north american opossum, insectivores and some rodents. in comparison with ...	1994	7887182
the marsupial mitochondrial genome and the evolution of placental mammals.	the entire nucleotide sequence of the mitochondrial genome of the american opossum, didelphis virginiana, was determined. two major features distinguish this genome from those of other mammals. first, five trna genes around the origin of light strand replication are rearranged. second, the anticodon of trna(asp) is posttranscriptionally changed by an rna editing process such that its coding capacity is altered. when the complete protein-coding region of the mitochondrial genome is used as an out ...	1994	8056314
murine typhus: updated roles of multiple urban components and a second typhuslike rickettsia.	studies using serologic and polymerase chain reaction-(pcr) facilitated analysis of field samples from southern texas indicate the presence of rickettsia typhi and elb agent infected cat fleas, ctenocephalides felis (bouché), and the first observation of elb infected vertebrates (opossums). the elb agent is a recently described typhus-like rickettsia that is not distinguished from r. typhi or r. prowazekii by currently available serologic reagents. restriction digests of pcr products from 399 fl ...	1994	7966170
ectoparasites of opossums and raccoons in southeastern georgia.	twelve species of ectoparasites (four fleas, three ticks, three chiggers, one macronyssid mite, and one atopomelid mite) were recovered from 42 opossums, didelphis virginiana kerr, live-trapped from september 1992 through april 1994 in southeastern georgia. the fleas, ctenocephalides felis (bouché) (prevalence = 19%) and polygenis gwyni (c. fox) (36%); the ticks, dermacentor variabilis (say) (40%) and ixodes scapularis say (19%); and the macronyssid mite, ornithonyssus wernecki (fonseca) (21%), ...	1994	7815408
development of early cell lineages in marsupial embryos: an overview.	all major embryonic and extra-embryonic cell lineages are established before implantation in marsupials. in reptiles, birds, monotremes and most marsupials, the zygote is polarized, sometimes markedly so, and the cleavage pattern in relation to the polarized state provides the mechanism for the generation of positional signals. these ensure that the embryonic cell lineages develop in the centre of the developing blastoderm or blastocyst epithelium and the extra-embryonic lineages at the peripher ...	1994	7878224
locomotory energetics and metabolic fuel reserves of the virginia opossum.	marsupials have lower resting metabolic rates than placental mammals, but it is not clear whether particular species can extend this energetic advantage to locomotion. some active marsupials have a low cost of locomotion, but other more sedentary species, such as the virginia opossum, appear to run very inefficiently. steady-state rates of o2 consumption (vo2) and co2 production (vco2) were measured at rest and during horizontal treadmill exercise in wild-caught, trained opossums. average daily ...	1994	7852899
perivitelline space of marsupial oocytes: extracellular matrix of the unfertilized oocyte and formation of a cortical granule envelope following the cortical reaction.	the purpose of this study was to characterize the structure of the vestments surrounding unfertilized and cortical granule-reacted oocytes from a marsupial, the grey short-tailed opossum monodelphis domestica and to determine if a cortical granule envelope (cge) forms in the perivitelline space (pvs) following the cortical reaction. unfertilized oocytes collected from mature ovarian follicles and oviducal oocytes that had undergone a cortical reaction were fixed for electron microscopy in the pr ...	1995	8588937
nucleotide sequence of a marsupial line-1 element and the evolution of placental mammals.	l1 (line-1) elements, previously described in several placental species, were shown to exist in several thousands of copies dispersed in the genome of a marsupial (the north american opossum, didelphis virginiana). a restriction fragment containing the partial nucleotide sequence of the reverse transcriptase gene (orf-2) from the marsupial l1 element was cloned and sequenced. the element was shown to evolve in concert within the marsupial when compared to placental mammals. when the marsupial l1 ...	1995	7476141
insulin-like growth factor improves renal architecture of fetal kidneys with complete ureteral obstruction.	others have previously demonstrated that the administration of insulin-like growth factor-i accelerates recovery from ischemic acute tubular necrosis in the rat kidney. we investigated the effect of insulin-like growth factor-i on the histology of unilaterally obstructed kidneys in the pouch young of the north american opossum, didelphis virginiana. in this model complete unilateral ureteral obstruction reliably induces statistically significant degrees of caliceal dilatation, tubular cystic cha ...	1995	7609156
the distribution of gap-43 immunoreactivity in the central nervous system of adult opossums (didelphis virginiana) with notes on their development.	the distribution of the growth associated protein gap-43 has been described in the brain and spinal cord of rats and other placental mammals but not marsupials. in order to provide such information, we employed a monoclonal antibody to immunostain for gap-43 in the central nervous system of adult and developing opossums, didelphis virginiana. the gap-43 immunoreactivity was widely distributed in the brain of adult opossums, but it was particularly dense within specific layers of the olfactory bu ...	1995	7749727
effect of deer exclusion on the abundance of immature ixodes scapularis (acari: ixodidae) parasitizing small and medium-sized mammals.	effects of deer exclusion on abundance of immature ixodes scapularis say parasitizing small and medium-sized mammals, and the role mammals have in introducing ticks to exclosure areas, were examined at two sites in westchester county, new york. in total, 686 mammal captures representing nine species were obtained, with white-footed mice, peromyscus leucopus rafinesque, composing > 80% of all captures, followed by raccoons, procyon lotor (l.); opossums, didelphis virginiana (kerr); and striped sk ...	1995	7869342
sarcocystis falcatula from passerine and psittacine birds: synonymy with sarcocystis neurona, agent of equine protozoal myeloencephalitis.	equine protozoal myeloencephalitis (epm) is a neurologic disease of horses caused by sarcocystis neurona. the horse is a dead-end host for s. neurona and the definitive and intermediate hosts have not previously been identified. we hypothesized that s. neurona is actually sarcocystis falcatula, a parasite that cycles in nature between virginia opossums (didelphis virginiana) and any of a variety of avian intermediate hosts. we extracted dna from s. falcatula sarcocysts in the muscle of a brown-h ...	1995	8544067
man and the chimaera. selective versus neutral oxytocin evolution.	the oxytocin/vasopressin superfamily encompasses vertebrate and invertebrate peptides and therefore the ancestral gene encoding the precursor protein antedates the divergence between the two groups, about 700 million years ago. the preserved nonapeptide pattern indicates that both the precursor structures and the processing enzymatic machinery were greatly conserved to ensure the building of a specific conformation. substitutions, which may be neutral or selective, occurred in precise positions. ...	1995	8714026
identification of opossums (didelphis virginiana) as the putative definitive host of sarcocystis neurona.	sarcocystis neurona is an apicomplexan that causes equine protozoal myeloencephalitis (epm) in north and south america. horses appear to be an aberrant host, because the merozoites continually divide in the central nervous system, without encysting. the natural host species has not previously been identified. the small subunit ribosomal rna (ssurna) gene of s. neurona was compared to those of sarcocystis muris, sarcocystis cruzi, toxoplasma gondii, and cryptosporidium parvum to identify a unique ...	1995	8544064
molecular anatomy of an endodermal gland: investigations on mucus glycoproteins and cell turnover in brunner's glands of didelphis virginiana using lectins and pcna immunoreactivity.	brunner's glands are located in the submucosa of the proximal duodenum and are unique to mammalian species. the north american opossum (didelphis virginiana) is generally regarded as a prototype marsupial that closely resembles fossil didelphids which can be placed at the beginning of mammalian evolution. the current investigation provided an opportunity for the analysis of secretory products from these glands in a species thought to be more closely related to earlier evolutionary forms. extract ...	1995	7642723
effects on breathing of medullary bicuculline microinjections in immature opossums.	the role of medullary gamma-aminobutyric acid a (gabaa)-receptor activation in the expression of breathing was studied in suckling opossums (didelphis virginiana) from 4 to 8 wk of age. animals were anesthetized with a thiobarbiturate, and the ventral medulla was exposed so that drugs could be microinjected into the medulla with a two-barrel glass micropipette. the gabaa antagonist bicuculline at approximately 1-3 pmol total dose was injected in volumes < 1 nl; injections of saline with pontamin ...	1995	8594928
cytoarchitecture of the substantia nigra pars lateralis in the opossum (didelphis virginiana): a correlated light and electron microscopic study.	the substantia nigra has been divided into three subdivisions. however, the cytoarchitecture of one of these subdivisions, the pars lateralis (snl), has not been previously examined in detail at the light and electron microscopic levels in any species. in the adult opossum, the three nigral subdivisions can be easily distinguished as distinct, rostrocaudally oriented cell groups separated by neuron-free zones. thus it was possible to determine the boundaries of the snl unambiguously. this report ...	1995	7604970
developmental progression of gpd expression from the inactive x chromosome of the virginia opossum.	metatherian (marsupial) mammals possess a non-random form of x-chromosome inactivation in which the paternally-derived x is always the one inactivated. to examine the progression of x-linked gene expression during metatherian development, we compared relative levels of the maternally and paternally encoded gpd gene products in heterozygous female virginia opossums (didelphis virginiana) across a major portion of the developmental period. panels of tissues obtained from fetuses, newborns, and pou ...	1995	7641417
distribution of corticotropin-releasing factor (crf) binding sites in the opossum cerebellum.	corticotropin-releasing factor (crf) has been demonstrated in the hypothalamic-pituitary-adrenal axis and studied in extrahypothalamic sites throughout the brain. localization of crf immunoreactivity, crf mrna, and crf receptors within specific brain areas supports an extrahypothalamic function for crf. previous reports have revealed the localization of several peptides, including crf, in the cerebellar cortex and nuclei of the north american opossum (didelphis marsupialis virginiana); climbing ...	1995	7746352
adenosine deaminase isoenzymes of the opossum didelphis virginiana: initial chromatographic and kinetic studies.	extracts of liver and spleen were used to isolate opossum adenosine deaminase isoenzymes (ada1 and ada2) and to determine their activities with adenosine and 2'-deoxyadenosine as substrates. km values (microm) for adenosine and 2'-deoxyadenosine, respectively, as substrates for partially purified opossum liver adenosine deaminase isoenzymes were ada1: 57 +/- 7 vs. 26 +/- 4 and ada2: 285 +/- 25 vs. 580 +/- 92. in crude spleen extract, ada2 activity was stable at 56 degrees c during 40 min of incu ...	1995	7599990
milk composition in the north american opossum (didelphis virginiana).	the composition of milk samples collected from captive opossums (didelphis virginiana) was determined at various intervals during lactation. the milk solids increased from 9% at week one to a maximum of 34% at 11 weeks post-partum. there were changes in the relative proportions of protein, lipid and carbohydrate at different stages of lactation. lipid represented the greatest fraction of the solids except for a period at mid-lactation when there was a peak in protein concentration. the concentra ...	1996	8829811
evidence for gap-43 within descending spinal axons in the north american opossum, didelphis virginiana.	we have shown previously that gap-43, a growth associated protein characteristically present in growing and regenerating axons, is relatively abundant in the spinal cord of adult opossums. in the present study, we combined the orthograde transport of the fluorescent marker fluoro-ruby with immunofluorescence for gap-43 to determine if any of it is present within descending spinal axons. when fluoro-ruby was injected into the red nucleus and midbrain tegmentum, the medial pontine or medullary ret ...	1996	9156783
auditory quality cues are more effective than auditory location cues in a r--no r (go--no go) differentiation: the extension of the rule to primitive mammals (american opossum, didelphis virginiana).	discrimination learning of instrumental responses to auditory compound stimuli was investigated in opossums using the r-no r (go-no go) differentiation. each compound stimulus consisted of two factors: quality and location. each correct response performed to the conditioned positive, or "safe" stimulus, was rewarded by food and never punished. each incorrect response performed to the conditioned negative, or "warning" stimulus, was punished by an electric shock. in subsequent testing, each oposs ...	1996	9033130
evidence for growth of supraspinal axons through the lesion after transection of the thoracic spinal cord in the developing opossum didelphis virginiana.	in the present study, we asked whether supraspinal axons grow through a complete transection of the spinal cord in the developing opossum didelphis virginiana. when the thoracic cord was transected at postnatal day (pd) 5 and bilateral injections of fast blue (fb) were made four segments caudal to the lesion 30-40 days later, fb-containing neurons were found in each of the supraspinal nuclei labeled by comparable injections in age-matched unlesioned controls. continuity between the cut ends of t ...	1996	8835721
growth of dorsal spinocerebellar axons through a lesion of their spinal pathway during early development in the north american opossum, didelphis virginiana.	supraspinal axons grow around or through lesions of their spinal pathway during specific critical periods of mammalian development, but comparable plasticity has not been documented for axons which form ascending tracts. in the present study, we asked whether axons of the dorsal spinocerebellar tract (dsct) are capable of such growth. the spinal cord of the north american opossum, didelphis virginiana, was hemisected at mid-thoracic levels between postnatal day (pd) 5 and 68 and after varying su ...	1996	8804690
topography, architecture, and connections of somatosensory cortex in opossums: evidence for five somatosensory areas.	microelectrode maps of somatosensory inputs were related to cortical architecture and patterns of cortical connections to provide evidence for five subdivisions of the somatosensory or sensorimotor cortex in north american opossums (didelphis marsupialis). microelectrode recordings revealed three systematic representations of the body surface. a large mediolaterally oriented representation was identified as the primary somatosensory area (s1) by its relative position, somatotopy, architecture, a ...	1996	8866849
evolution of transthyretin gene expression in the liver of didelphis virginiana and other american marsupials.	the occurrence of the thyroid hormone-binding plasma protein transthyretin in the bloodstream was investigated for four american marsupial species. serum samples were analyzed by incubation with radioactive t4, followed by electrophoresis, then autoradiography, and western blotting. transthyretin was found in serum from monodelphis domestica, didelphis virginiana, caluromys lanatus, and dromiciops australis. for unambiguous identification, transthyretin from d, virginiana was purified from serum ...	1996	8754780
ontogeny of suckling mechanisms in opossums (didelphis virginiana).	although adult mammals have several different mechanisms for drinking liquids, relatively little is known about the variation in mechanisms used by infants for suckling and how the mechanics of suckling change as a function of ontogeny. we examined suckling in infant opossums, animals that as adults use a lapping mechanism to drink. the youngest infants (45 days old) used a suction, pumping mechanism, based on dorsal/ventral tongue movements, similar to what has been documented in infant primate ...	1996	8872320
ticks (acari: ixodidae) in bulloch county, georgia.	an 18-mo study was conducted in bulloch county, georgia, to determine tick species composition, seasonal activity of individual tick species, and host-tick associations. the following 7 methods of tick collection were included: (1) live trapping of potential host animals, (2) checking wild game, (3) drag sampling, (4) carbon dioxide attraction, (5) checking livestock, road kills, nests, and burrows, (6) samples submitted from veterinarians, and (7) ticks collected by local residents and submitte ...	1996	8742526
a molecular and evolutionary study of the beta-globin gene family of the australian marsupial sminthopsis crassicaudata.	beta-globin gene families in eutherians (placental mammals) consist of a set of four or more developmentally regulated genes which are closely linked and, in general, arranged in the order 5'-embryonic/fetal genes-adult genes-3'. this cluster of genes is proposed to have arisen by tandem duplication of ancestral beta-globin genes, with the first duplication occurring 200 to 155 mybp just prior to a period in mammalian evolution when eutherians and marsupials diverged from a common ancestor. in t ...	1996	8752008
morphological observations on the mesonephros in the postnatal opossum, didelphis virginiana.	the mesonephros of the opossum persists for 3-4 weeks into the postnatal period. based on our observations of its structure, and the vital dye experiments of others, it appears that the opossum mesonephros is functional during the first 10 days of the postnatal period. the mesonephros of the newborn opossum consists of 35-45 nephron units which are structurally very similar to metanephric nephrons except that they lack a loop of henle. by the end of the first postnatal week, regression which pro ...	1996	500493
methylation analysis of a marsupial x-linked cpg island by bisulfite genomic sequencing.	paternal x chromosome inactivation occurs in rodent extraembryonic membranes and in all tissues of marsupials. methylation of cpg islands occurs on the inactive x in eutherians and is considered to be a stabilizing mechanism. the only previous study of a marsupial x-linked cpg island was of the g6pd gene of the virginia opossum, in which the paternally derived allele is not completely repressed. we have cloned the 5' end of the g6pd gene from an australian marsupial, the common wallaroo, and seq ...	1996	8919690
development of the lymphoid tissues of the tammar wallaby macropus eugenii.	a study has been made of the development of four lymphoid tissues from birth to maturity in the tammar wallaby macropus eugenii--the cervical and thoracic thymus, lymph nodes and gut-associated lymphoid tissue (galt). the development of these tissues in the tammar wallaby is similar to that in two other marsupials, the quokka setonix brachyurus and the virginian opossum didelphis virginiana. lymphocytes were first detected in the cervical thymus of the tammar at day 2 post partum and in the thor ...	1997	9208435
experimental induction of equine protozoal myeloencephalitis in horses using sarcocystis sp. sporocysts from the opossum (didelphis virginiana).	sarcocystis sp. sporocysts isolated from eight feral opossums (didelphis virginiana) were pooled and fed to 18 commercially reared budgerigars (melopsittacus undulatus), 14 wild-caught sparrows (passer domesticus), one wild-caught slate-colored junco (junco hyemalis) and five weanling horses (equus caballus). all budgerigars died within 5 weeks post inoculation (wpi). histologic examination revealed meronts within the pulmonary epithelia and typical sarcocystis falcatula sarcocysts developing in ...	1997	9066066
early development and developmental plasticity of the fasciculus gracilis in the north american opossum (didelphis virginiana).	the first objective of the present study was to ask when axons of the fasciculus gracilis reach the nucleus gracilis in the north american opossum (didelphis virginiana). when fast blue (fb) was injected into the lumbar cord on postnatal day (pd) 1 and the pups were killed 2 days later, labeled axons were present within a distinct fasciculus gracilis at thoracic and cervical levels of the cord. when comparable injections were made at pd3 or 5 and the pups were allowed to survive for the same tim ...	1997	9051256
north american opossum didelphis virginiana as a fetal nephrotoxicity model: histologic and ultrastructural assessment of uranyl nitrate (un)-induced damage.	we have used our opossum model of fetal nephrotoxicity to investigate uranyl nitrate-induced morphologic changes in the developing kidney. the present study establishes a renal dose response curve for the uranyl nitrate (un). we find that pups treated with nonlethal doses of un do not demonstrate growth retardation compared to saline-treated controls. the kidneys of un-treated pups are heavier than the control animals, an effect less apparent the longer the pups are followed. a low dose of 60 mg ...	1997	9372500
glucose kinetics of the virginia opossum: possible implications for predicting glucose turnover in mammals.	primed continuous infusions of 6-3h-glucose, respirometry and measurements of nitrogen excretion were carried out in adult virginia opossums (didelphis virginiana). our goals were to determine resting glucose turnover rate, to establish the relative importance of this oxidative fuel in the energy budget of this species, to assess whether metabolic rate is a better predictor of glucose turnover rate than body mass and to demonstrate that glucose kinetics can be measured in the opossum for future ...	1997	9406445
developmental plasticity of selected spinocerebellar axons. studies using the north american opossum, didelphis virginiana.	when the thoracic spinal cord of the opossum is hemisected at postnatal day 5 or 8, but not at day 12 or later ages, spinocerebellar axons which originate from spinal border cells, the sacral/coccygeal ventrolateral nucleus, and stilling's nucleus grow through the lesion and reach the cerebellum. the critical period for such growth is comparable to that reported previously for spinocerebellar axons originating within clarke's nucleus and for axons of the fasciculus gracilis, but shorter than tha ...	1997	9352116
l-arginine deficiency causes suppression of nonadrenergic noncholinergic nerve-mediated smooth muscle relaxation: role of l-citrulline recycling.	studies were performed on the internal anal sphincter (ias) smooth muscle strips obtained from opossums (didelphis virginiana). isometric tension and l-arginine levels of the tissues were measured under basal conditions, in the presence of electrical field stimulation (efs) and after treatment with different concentrations of arginase. for the nonadrenergic noncholinergic nerve stimulation, short trains (4 sec) as well as continuous efs were used. during continuous efs, after the initial ias rel ...	1997	9223577
ontogeny and limb bone scaling in two new world marsupials, monodelphis domestica and didelphis virginiana.	this study examines the growth of two species of marsupials who share common ancestry and are born at the same neonatal size of a little less than 1 g. despite this similarity at birth, adult size of these two species differs by about 50 times, with the smaller species believed to be the more ancestral. we quantified the growth in the limb bones (humerus, femur, ulna, tibia, metacarpal, and metatarsal) beginning around 40 days of age until adult size was reached. results indicate that the larger ...	1997	8989872
didelphid behavior.	there are approximately 75 species of american opossums (didelphids). systematic behavioral research has been reported for only a small number of species, namely, monodelphis domestica and didelphis virginiana. observational studies and field reports on several other didelphid species have also been published. the current review covers behavioral studies on didelphids including research on territoriality, reproductive behaviors, parturition, maternal behaviors, nest-building, vocalizations, scen ...	1997	9168270
snake envenomation and protective natural endogenous proteins: a mini review of the recent developments (1991-1997).	the properties of several factors--antihaemorrhagic, antineurotoxic, antimyotoxic--isolated from the blood serum or plasma of different animals are described with more emphasis placed on the structural differences and similarities among the factors of the snake (trimeresurus flavoviridis) and mammals (didelphis marsupials and herpestes edwardsii). classification of antihaemorrhagic factors of snake and mammals according to structural homologies, and their effectiveness in neutralizing venom haem ...	1998	9792161
a review of histogenesis/organogenesis in the developing north american opossum (didelphis virginiana).		1998	9816726
a review of histogenesis/organogenesis in the developing north american opossum (didelphis virginiana).		1998	9816723
origin, course, and laterality of spinocerebellar axons in the north american opossum, didelphis virginiana.	spinocerebellar axons have been studied extensively in placental mammals, but there have been no full reports on their origin, laterality, or spinal course in any marsupial. we have used the north american opossum (didelphis virginiana) to obtain such information and to ask whether any spinocerebellar neurons innervate both the anterior and posterior lobes of the cerebellum through axonal collaterals. to identify spinal neurons that project to the cerebellum, we employed the retrograde transport ...	1998	9713988
regeneration of supraspinal axons after transection of the thoracic spinal cord in the developing opossum, didelphis virginiana.	when the thoracic spinal cord of the north american opossum is transected early in development, supraspinal axons grow through the lesion. in the experiments reported here, we asked whether regeneration of cut axons contributes to such growth. fast blue (fb) was injected into the lumbar cord on postnatal day (pd)5, 8, 15, or 20. five days later, fb was removed by gentle suction, and the spinal cord was transected at thoracic levels. fourteen days later, rhodamine b dextran was injected between t ...	1998	9703028
adult opossums (didelphis virginiana) demonstrate near normal locomotion after spinal cord transection as neonates.	when the thoracic spinal cord of the north american opossum (didelphis virginiana) is transected on postnatal day (pd) 5, the site of injury becomes bridged by histologically recognizable spinal cord and axons which form major long tracts grow through the lesion. in the present study we asked whether opossums lesioned on pd5 have normal use of the hindlimbs as adults and, if so, whether that use is dependent upon axons which grow through the lesion site. the thoracic spinal cord was transected o ...	1998	9582254
the detection of hemorrhagic proteins in snake venoms using monoclonal antibodies against virginia opossum (didelphis virginiana) serum.	most snakes and a few warm-blooded animals have a resistance to snake venoms because of naturally occurring antihemorrhagins found in their sera. the antihemorrhagins in serum of virginia opossum (didelphis virginiana) neutralize hemorrhagic activity by binding to hemorrhagins in snake venoms. the binding characteristic of antihemorrhagins in d. virginiana serum was used to develop a five-step western blot. the detection of hemorrhagic proteins were measured indirectly with antihemorrhagins in v ...	1998	9723843
seroprevalence of antibodies against toxoplasma gondii in free-ranging mammals in iowa.	serum samples from raccoons (procyon lotor), striped skunks (mephitis mephitis), virginia opossums (didelphis virginiana), and free-ranging house cats trapped in iowa between 1984 and 1988 were tested for antibodies against toxoplasma gondii using the modified direct agglutination test (mat). antibody titers > or = 1:32 were considered indicative of infection. prevalence rates by species were estimated for raccoons at 134/885 (15%), skunks at 38/81 (47%), opossums at 12/53 (23%), and cats at 16/ ...	1998	9813854
mycobacterium bovis in coyotes from michigan.	during a survey for tuberculosis in wild carnivores and omnivores, mycobacterium bovis was cultured from pooled lymph nodes of three adult female coyotes (canis latrans) harvested by hunters in michigan (usa). no gross or histologic lesions suggestive of tuberculosis were seen in these animals. one coyote was taken from montmorency county and two coyotes from alcona county located in the north-eastern portion of michigan's lower peninsula where free-ranging white-tailed deer (odocoileus virginia ...	1998	9706576
isolation in immunodeficient mice of sarcocystis neurona from opossum (didelphis virginiana) faeces, and its differentiation from sarcocystis falcatula.	sarcocystis neurona was isolated in nude mice and gamma-interferon knockout mice fed sporocysts from faeces of naturally infected opossums (didelphis virginiana). mice fed sporocysts became lethargic and developed encephalitis. protozoa were first found in the brain starting 21 days post-inoculation. sarcocystis neurona was recovered in cell culture from the homogenate of liver, spleen and brain of a nude mouse 11 days after feeding sporocysts. the protozoa in mouse brain and in cell culture mul ...	1998	9925260
isolation of a third species of sarcocystis in immunodeficient mice fed feces from opossums (didelphis virginiana) and its differentiation from sarcocystis falcatula and sarcocystis neurona.	opossums (didelphis virginiana) were found to be hosts for 3 species of sarcocystis: sarcocystis falcatula with an avian intermediate host, s. neurona with an undetermined intermediate host, and a third, unnamed, species. sporocysts from the intestines of 2 opossums (nos. 26 and 47) were fed to budgerigars (melopsittacus undulatus), nude mice, and gamma-interferon knockout (ko) mice. sporocysts of s. falcatula were not infective to nude or ko mice. sporocysts of s. neurona induced encephalitis i ...	1998	9920306
the electrocardiogram of the virginia opossum (didelphis virginiana).		1998	106584
postnatal changes in blood respiratory characteristics in an american opossum (didelphis virginiana).	the oxygen affinity of opossum blood changes in the postnatal period. the youngest opossums studied were 53 days of age (dated from the day of transit from vagina to pouch) and still confined to the maternal pouch: they had a blood p50 of 32.6 +/- 2.9 mm hg. the blood p50 value then increased significantly, in two steps. first, while the young were still in the pouch, blood p50 rose secondary to a rise in the concentration of 2,3-diphosphoglycerate (dpg). blood p50 and dpg concentration then rem ...	1999	15307
implications of raccoon latrines in the epizootiology of baylisascariasis.	raccoons (procyon lotor) frequently establish defecation sites, termed latrines, on large logs, stumps, rocks, and other horizontally oriented structures/surfaces. these latrines are important foci of infective eggs of baylisascaris procyonis, a nematode parasite of raccoons which is pathogenic to numerous species of mammals and birds. to examine the role of raccoon latrines in this animal-parasite interaction, we documented animal visitations to raccoon latrines in two large forested tracts and ...	1999	10479081
sarcocystis speeri n. sp. (protozoa: sarcocystidae) from the opossum (didelphis virginiana).	the north american opossum (didelphis virginiana) is host to at least 3 species of sarcocystis: sarcocystisfalcatula, sarcocystis neurona, and a recently recognized sarcocystis sp. a new name, sarcocystis speeri, is proposed for the third unnamed sarcocystis. immunodeficient mice are an experimental intermediate host for s. speeri. sarcocystis speeri sporocysts are 12-15 x 8-10 microm in size, and its schizonts are found in many organs of mice. sarcocysts of s. speeri are found in skeletal muscl ...	1999	10577729
oral rabies vaccine contact by raccoons and nontarget species in a field trial in florida.	rabies is enzootic in raccoons (procyon lotor) in the eastern united states. oral vaccination of free-ranging raccoons against rabies has the potential to control the disease in a principal reservoir and reduce the risk of rabies exposure among domestic animals and humans. free-ranging animal contact with baits containing a vaccinia virus recombinant vaccine expressing the rabies glycoprotein gene (v-rg) was monitored in pinellas county (florida, usa) from february through may 1997. bait contact ...	1999	10574527
are sarcocystis neurona and sarcocystis falcatula synonymous? a horse infection challenge.	equine protozoal myeloencephalitis (epm) is a debilitating neurologic disease of the horse. the causative agent. sarcocystis neurona, has been suggested to be synonymous with sarcocystis falcatula, implying a role for birds as intermediate hosts. to test this hypothesis, opossums (didelphis virginiana) were fed muscles containing s. falcatula sarcocysts from naturally infected brown-headed cowbirds (molothrus ater). ten horses were tested extensively to ensure no previous exposure to s. neurona ...	1999	10219313
subretinal macrophages in the developing eye of eutherian mammals and marsupials.	blood-borne mononuclear cells invade the developing retina via the hyaloid vasculature at the optic nerve head. following removal of apoptotic cell debris they give rise to the network of resident microglia. the population of cells recently described in the peripheral subretinal space of developing human eyes may represent a further population of macrophages destined to become microglia. the aim of the present study was to confirm the presence of subretinal macrophages in the developing eye in o ...	1999	10526023
ticks and antibodies to borrelia burgdorferi from mammals at cape hatteras, nc and assateague island, md and va.	results of a survey for ixodid ticks and/or serum antibodies to borrelia burgdorferi from 14 species of small to large mammals from eastern coastal areas of the united states are presented. most samples were obtained from july 1987 through june 1989 (excluding december-march) at 3 locales: assateague is. national seashore, worcester co., md., and accomack co., va. (approximately 38 degrees 05' n 75 degrees 10' w), and cape hatteras national seashore, dare co., nc (approximately 35 degrees 30' n ...	1999	10534951
patterns of infestation by adult dermacentor variabilis (acari: ixodidae) in a mark-recapture study of raccoons (mammalia: carnivora) and virginia opossums (mammalia: didelphimorphia) in tennessee.	a mark-recapture study of raccoons (procyon lotor l.) and virginia opossums (didelphis virginiana kerr) was conducted from february 1991 through april 1994 to determine host interactions with adult dermacentor variabilis say. we captured 1,293 raccoons and virginia opossums during the 3-yr study (140 individual raccoons and 160 individual virginia opossums) with 1,895 adult d. variabilis collected. raccoons had a significantly higher mean intensity and higher prevalence of adult ticks than virgi ...	1999	10337094
site selection by intestinal helminths of the virginia opossum (didelphis virginiana).	digestive tract helminths of the virginia opossum (didelphis virginiana) were examined for site specificity and interspecific interactions. thirty opossums were live-trapped at 2 localities in georgia, killed, and their digestive tracts removed and divided into the following sections; esophagus, stomach, small intestine (20 equal sections), cecum, and large intestine (5 equal sections). helminths present in each section were identified and counted. three trematode, 1 cestode, 2 acanthocephala, a ...	1999	10207354
multiple dna markers differentiate sarcocystis neurona and sarcocystis falcatula.	studies designed to investigate the causative agent of equine protozoal myeloencephalitis and its life cycle have been hampered by the marked similarity of sarcocystis neurona to other sarcocystis spp. present in the same definitive host. random-amplified polymorphic dna techniques were used to amplify dna from isolates of s. neurona and sarcocystis falcatula. dna sequence analysis of polymerase chain reaction (pcr) products was then used to design pcr primers to amplify specific sarcocystis spp ...	1999	10219299
rescue of axotomized rubrospinal neurons by brain-derived neurotrophic factor (bdnf) in the developing opossum, didelphis virginiana.	many rubrospinal neurons die in developing opossums when their axon is cut at thoracic levels of the spinal cord and in the present study we asked whether they can be rescued by brain-derived neurotrophic factor (bdnf). bilateral injections of fast blue (fb) were made into the rostral lumbar cord to prelabel rubrospinal neurons and 5 days later the rubrospinal tract was cut unilaterally by hemisecting the thoracic cord. immediately after hemisection, bdnf-soaked gelfoam was placed into the lesio ...	1999	10611517
screening for fibrinolytic activity in eight viperid venoms.	snake venoms contain direct-acting fibrinolytic metalloproteinases (mmp) that could have important applications in medicine. fibrinolytic enzymes isolated from venom can induce in vitro clot lysis by directly acting on a fibrin clot. the most ideal fibrinolytic enzyme would have high affinity for clots, dissolve clots directly without causing hemorrhage, and would not be neutralized in vivo by endogenous metalloproteinase inhibitors. the purpose of this study was to compare deae/hplc venom profi ...	1999	10579653
characterization of metastatic intestinal adenocarcinoma with differentiation into multiple morphologic cell types in a virginia opossum.	a captively maintained mature male opossum (didelphis virginiana) utilized in a research protocol was presented with clinical signs of chronic diarrhea and severe muscle wasting. at necropsy, there was multifocal mural gastric, intestinal, and urinary bladder thickening, concurrent bilateral hydroureter and hydronephrosis, and extensive fibrous abdominal adhesions. histologic evaluation revealed intestinal adenocarcinoma with coelomic metastasis to the stomach and urinary bladder. the adenocarci ...	1999	10490217
field immobilization and euthanasia of american opossum.	seventeen recently trapped opossum, didelphis virginiana, (median weight 2.45 kg; range = 1.6-5.0 kg; quartiles = 1.8-3.3 kg) were immobilized with either telazol (15 or 30 mg/kg) or a mixture of medetomidine (100 micrograms/kg), butorphanol (0.2 mg/kg), and ketamine hcl (10 mg/kg) based on estimated weights. anesthetized animals were subjected to cardiac puncture for blood withdrawal and toe pinch. euthanasia was accomplished by intracardiac administration of 1 ml of concentrated pentobarbital ...	1999	10073367
developmental plasticity of ascending spinal axons studies using the north american opossum, didelphis virginiana.	the objectives of the present study were to determine if axons of all ascending tracts grow through the lesion after transection of the thoracic spinal cord during development in the north american opossum, and if so, whether they reach regions of the brain they normally innervate. opossum pups were subjected to transection of the mid-thoracic cord at pd5, pd8, pd12, pd20, or pd26 and injections of fast blue (fb) into the lower thoracic or upper lumbar cord 30-40 days or 6 months later. in the p ...	1999	9974160
development of epiphyseal structure and function in didelphis virginiana (marsupiala, didelphidae).	this study addressed the question of how the epiphyses of growing mammals change their external shape and internal architecture during postnatal development. ontogenetic transformations in the external form and internal structure of the fore- and hindlimb epiphyses were examined in a mixed cross-sectional sample of didelphis virginiana using two methods: morphometric analysis of linear epiphyseal dimensions and histological staining of serially sectioned epiphyses. metric data indicate that virg ...	1999	29847889
repair of the transected spinal cord at different stages of development in the north american opossum, didelphis virginiana.	when the thoracic spinal cord is transected on postnatal day (pd) 5 in the north american opossum, descending and ascending axons grow through the lesion site. when the lesion is made on pd20, comparable growth is limited to a subset of descending axons. to better understand the mechanisms underlying these differences, we analyzed the transection site at different times after lesioning at both ages. axons which crossed the lesion site could be identified using silver impregnation and immunostain ...	2000	11179852
regeneration of descending spinal axons after transection of the thoracic spinal cord during early development in the north american opossum, didelphis virginiana.	opossums are born in an immature, fetal-like state, making it possible to lesion their spinal cord early in development without intrauterine surgery. when the thoracic spinal cord of the north american opossum, didelphis virginiana, is transected on postnatal day 5, and injections of fast blue (fb) are made caudal to the lesion site 30-40 days or 6 months later, neurons are labeled in all of the spinal and supraspinal areas that are labeled after comparable injections in age-matched, unlesioned ...	2000	11165803
granulomatous pneumonia in the opossum (didelphis virginiana) associated with an intracellular fungal agent.	two of nine female opossums (didelphis virginiana) in a closed breeding colony were submitted for necropsy due to a history of poor reproductive performance in the absence of overt clinical disease. on histologic examination, marked granulomatous to pyogranulomatous pneumonia was identified in these animals.	2000	10894501
energy metabolism of the virginia opossum during fasting and exercise.	rates of oxygen consumption and co(2) production were measured in virginia opossums (didelphis virginiana) during fasting and prolonged exercise to quantify changes in total energy expenditure and oxidative fuel selection. we hypothesized that fasting would cause metabolic depression and a progressive shift towards lipid utilization to spare alternative substrates. it was also predicted that prolonged exercise would cause the same relative changes in fuel preference as fasting, but on a compress ...	2000	10729284
isolation and characterization of dm40 and dm43, two snake venom metalloproteinase inhibitors from didelphis marsupialis serum.	from didelphis marsupialis serum, two antihemorrhagic proteins were isolated by deae-sephacel, phenyl-sepharose and superdex 200 and characterized. their masses by mass spectrometry were 40318 amu for dm40 and 42373 and 43010 amu for dm43, indicating the presence of isoforms for the last. molecular masses of 44.8 and 47.3 were obtained by sds-page, respectively for dm40 and dm43. both inhibitors showed isoelectric points lower than 3.5 and glycosylation percentages varying from 20.5 to 29.0%, as ...	2000	10779682