Publications

trypanosoma (megatrypanum) samueli n. sp., a trypanosomatidae isolated from monodelphis domesticus (wagner, 1842) (marsupiala).		2007	931316
antithrombin iii (at3) polymorphism in the marsupial monodelphis domestica: identification and genetics.	antithrombin iii polymorphism was observed in the gray short-tailed opossum, monodelphis domestica, by either one-dimensional polyacrylamide gel electrophoresis (page; ph 7.9), two-dimensional page (agarose, ph 5.4; 12% t, ph 7.9), or isoelectric focusing (ph 4.2-4.9) followed by immunoblotting with rabbit antiserum to human antithrombin iii. family studies demonstrated an inheritance of three codominant autosomal alleles, at3a, at3b, and at3c, and a population study revealed frequencies of 0.70 ...	1992	1296573
ultrastructural aspects of oocyte growth in the marsupial monodelphis domestica (grey short-tailed opossum).	the growth of the opossum monodelphis oocyte does not correspond to the strict biphasic pattern so far described in eutherians and marsupials. the oocyte increases appreciably in size during the last stage of antral follicle development. during the primordial and primary follicle stage balbiani bodies or paranuclear complexes are not detectable in monodelphis oocytes. organelles are randomly distributed. in addition to the nucleolus, perichromatin and ribonucleoprotein particles are other intran ...	1992	1304586
genetic diversity of laboratory gray short-tailed opossums (monodelphis domestica): effect of newly introduced wild-caught animals.	the colony of gray, short-tailed opossums (monodelphis domestica) at the southwest foundation for biomedical research, the primary supplier of this species for research purposes, was founded with nine animals trapped in 1978 in the state of pernambuco, brazil. since 1984, 14 newly acquired founders from the state of paraiba, brazil have contributed to the gene pool of the colony. the animals from paraiba and their descendants are significantly larger than the founders from pernambuco and their d ...	1981	1320155
unexpected oocyte growth after follicular antrum formation in four marsupial species.	during examination of maturing preovulatory marsupial oocytes we noted that oocyte diameters were invariably about 50% greater than the figures reported in earlier histological studies. as all previous investigations were limited to small follicles (at most 25% the size of the ovulating follicle), the present study was initiated to examine oocyte growth during the whole period of follicular development. oocyte and follicle diameters were measured for three australian (trichosurus vulpecula, macr ...	1992	1339855
olfactory bulb organization and development in monodelphis domestica (grey short-tailed opossum).	the olfactory bulbs of adult and developing monodelphis domestica were examined with a number of techniques. golgi, nissl, and timm stains as well as acetylcholinesterase histochemistry revealed a high degree of order within the adult bulb. all major cell classes characteristic of most mammalian species were observed. tufted cells appeared to be restricted to the superficial portion of the external plexiform layer. developing monodelphis pups were examined with nissl-stained semithin sections an ...	1992	1378458
purification and characterization of fibroblast growth factors from the opossum, monodelphis domestica, brain.	an extract from the brain of the opossum monodelphis domestica was fractionated by heparin affinity chromatography. a major peak of mitogenic activity (heparin binding growth factor 2, hbgf-2) eluted from heparin-sepharose between 1.7 and 2.0 m nacl. antisera specific for bovine bfgf detected four polypeptides of 17.5-23 kda in opossum brain hbgf-2 preparations. opossum brain heparin binding growth factor 1 (hbgf-1), a minor peak of activity, eluted from heparin-sepharose at 1.1 nacl and contain ...	1992	1380142
galanin-like immunoreactivity in the adult and developing brazilian opossum brain.	the distribution of galanin-like immunoreactivity has been characterized in the brain of the adult and developing brazilian opossum (monodelphis domestica). two commercially available antisera were used to examine the distribution of galanin-like immunoreactive (gal-ir) cells and fibers. nuclear groups containing gal-ir cell bodies and fibers were seen throughout the adult opossum brain. the distribution of gal-ir elements seen is similar to that reported for other mammals. based on these findin ...	1992	1380900
the origins of supraspinal projections to the cervical and lumbar spinal cord at different stages of development in the gray short-tailed brazilian opossum, monodelphis domestica.	we have used the retrograde transport of fast blue (fb) to study the origins of supraspinal projections to the lumbar and cervical spinal cord at different stages of development in the brazilian, short-tailed opossum, monodelphis domestica. monodelphis was chosen for study because its young are born in a very immature state, 14-15 days after copulation, making it possible to manipulate its nervous system in an embryonic state without intra-uterine surgery. when injections of fb were made into th ...	1992	1382891
evidence that cortical granule formation is a periovulatory event in marsupials.	formation of cortical granules was examined in superovulated oocytes from three marsupial species, brushtail possums (trichosurus vulpecula) tammar wallabies (macropus eugeniii) and grey short-tailed opossums (monodelphis domestica) and in oocytes obtained during natural cycles in macropus eugenii. superovulation was induced by pregnant mares' serum gonadotrophin/gonadotrophin-releasing hormone (pmsg/gnrh) protocols and natural ovulation by removal of pouch young. oocytes were collected after ov ...	1992	1404089
estrogen in peripheral plasma during postnatal development in gray short-tailed opossums.	plasma samples obtained from gray short-tailed opossums (monodelphis domestica) at selected ages through adulthood were assayed for estrogen (e). levels of e in one mixed-sex plasma pool of animals aged postnatal day (pd) 4 and one of two mixed-sex plasma pools of animals aged pd 8 were over 300 pg/ml. on pd 16, e levels in males and females averaged 30 and 47 pg/ml, respectively. while no significant sex differences in e levels were seen on pd 30 or pd 60, mean e levels for animals on pd 30 wer ...	1992	1409929
effects of chronic blood loss in a marsupial (monodelphis domestica).	monodelphis domestica, the gray short-tailed opossum, is used increasingly as an animal model in studies that require repeated blood sampling. consequently, it is important to establish safe bleeding regimens. we investigated the effects of repeated blood loss on various hematologic values and on different organs in this species. approximately 2 ml of blood were taken weekly from 20 animals for 13 weeks. the animals were then necropsied; members of an age- and sex-matched control group were bled ...	1992	1479808
specific chromosomal defects associated with ultraviolet radiation-induced cutaneous tumors in monodelphis domestica (marsupialia, mammalia).	cytogenetic analysis of eight ultraviolet radiation (uvr)-induced cutaneous tumors and one spontaneously transformed fibroblast cell line of monodelphis domestica showed that two of the tumor cell lines were of murine origin and that the remaining six marsupial tumor cell lines had hyperdiploid stemline numbers ranging from 21 to 31. each tumor cell line showed structural and numerical abnormalities. the single transformed fibroblast cell line also showed a hyperdiploid chromosome number with st ...	1992	1486565
sexual maturation in female gray short-tailed opossums, monodelphis domestica, is dependent upon male stimuli.	the development of physiological responsiveness to male stimuli in peripubertal female gray short-tailed opossums was examined in this study. prepubertal females were exposed directly or indirectly to male chemicals (odors) or to no male stimuli. all females exposed directly to deposited male stimuli (22/22) showed estrus at a mean (+/- sem) age of 127 +/- 2 days. only 59% (13/22) of females exposed indirectly showed estrus, and at an older mean age of 162 +/- 5 days (p less than 0.01). vaginal ...	1992	1536905
evidence for high levels of androgen in peripheral plasma during postnatal development in a marsupial: the gray short-tailed opossum (monodelphis domestica).	plasma samples were assayed for androgen in gray short-tailed opossums (monodelphis domestica) on the day of birth and at selected ages through adulthood. levels of androgen in mixed-sex plasma pools of animals 4 and 8 days of age were higher than in either sex at all other ages examined. at postnatal days 16, 30, and 60 (weaning), levels of androgen were equivalent in males and females and as high as in adult males. in both sexes, androgen levels were lower at postnatal day 84 (juveniles) than ...	1992	1547307
the differentiation of the skin and its appendages. i. normal development of papillary ridges.	in the present study, the normal development of papillary ridges was studied in the volar pads of both fore and hindpaws of the opossum, monodelphis domesticus. at birth, the developmental state of the opossum's paws is equivalent to that of a six-week human embryo. the development of papillary ridges in the opossum occurs entirely postnatally and the hindpaw lags behind the forepaw by at least four days in most developmental parameters. papillary ridge formation is preceded by four events: skin ...	1992	1554108
onset of neocortical synaptogenesis in neonatal monodelphis domestica (south american grey short-tailed opossum).		1992	1557699
identification of a transforming ras oncogene in an ultraviolet radiation-induced corneal tumor of monodelphis domestica.	chronic exposure of the gray, short-tailed oppossum, monodelphis domestica to ultraviolet radiation (uvr) induces mesenchymal tumors of the cornea. high molecular weight dna samples from 6 uvr-induced corneal tumors were assayed for their ability to transform nih 3t3 cells to tumorigenicity. nih 3t3 cells transfected with dna from 5 of the corneal tumors produced 14 tumors in nude mice. cell lines were established from these tumors. dna from 13 of 14 tumor cell lines contained repetitive opossum ...	1992	1561240
early differentiation of the gonads in the gray short-tailed opossum (monodelphis domestica).	the time course for gonadal development in gray short-tailed opossums was examined in this study. it was found that the gonads were not differentiated on day 1 of postnatal life (the day of birth). while testis development was seen by postnatal day 4, ovarian development did not occur until after postnatal day 16. in both sexes, primordial germ cells were not identified until after postnatal day 1. these findings are discussed with respect to gonadal differentiation in other marsupial species.	1992	1567932
proliferative responses of lymphocytes to mitogens in the gray, short-tailed opossum, monodelphis domestica.	a south american opossum (monodelphis domestica) is a model animal for studies on the health effects of exposure to ultraviolet radiation (uvr). as part of a broad evaluation of immune function in this animal, we have tested in vitro mitogenic responses using whole blood cultures. lymphocytes proliferated in the presence of phytohemagglutinin (pha), concanavalin a (con a), and pokeweed mitogen (pwm), but were unresponsive to bacterial lipopolysaccharide (lps).	1992	1570674
severely reduced recombination in females of the south american marsupial monodelphis domestica.	the gray short-tailed opossum, monodelphis domestica, is a model species for studying the underlying mechanisms that govern recombination. we have identified a new marker, pi (protease inhibitor), in m. domestica and demonstrate its linkage to ak1 (adenylate kinase 1). the rate of recombination in females of this species is approximately one fifth the rate in males, as might be predicted from the difference in chiasma frequency between the two sexes.	1992	1582262
biochemical genetics of alcohol dehydrogenase isozymes in the gray short-tailed opossum (monodelphis domestica).	polyacrylamide gel-isoelectric focusing (page-ief) methods were used to examine the multiplicity, tissue distribution, and biochemical genetics of alcohol dehydrogenase (adh) isozymes among gray short-tailed opossums (monodelphis domestica). seven adh isozymes were resolved and distinguished on the basis of their isoelectric points, tissue distributions, and substrate and inhibitor specificities. adh1 and adh2 exhibited class i properties and were observed in liver (and intestine) extracts. adh3 ...	1992	1616478
evidence from plasma progesterone concentrations for male-induced ovulation in the brush-tailed bettong, bettongia penicillata.	female brush-tailed bettongs, bettongia penicillata, were housed with either an intact or vasectomized male or isolated from males in the peripartum period. development of the quiescent corpus luteum formed at the post partum oestrus was initiated by removing the pouch young. blood samples for analysis of plasma progesterone were collected from the females 2 days before removal of pouch young, daily for 5 or 6 days and then 2-3 times each week until 19 days after removal of pouch young. plasma p ...	1992	1625245
hormonal evidence for induced ovulation in monodelphis domestica.	breeding activity in the south american grey opossum, monodelphis domestica, is stimulated by the presence of males. this study presents the first analysis of changes in concentrations of plasma progesterone during pregnant and nonpregnant cycles. in expt 1, females were paired with either intact or vasectomized males to stimulate a reproductive cycle, or were isolated from males. within 4-8 days of pairing, females showed marked changes in the size of the urogenital opening (vulva), which were ...	1992	1625246
dramatic differences in lipoprotein composition among gray short-tailed opossums (monodelphis domestica) fed a high cholesterol/saturated fat diet.	lipoproteins of gray short-tailed opossums (monodelphis domestica) were characterized to determine the basis of differences among individuals in response to a challenge diet enriched in saturated fat and cholesterol. animals were selected from two phenotypic groups (high and low plasma cholesterol response to the challenge diet). half of the animals in each group were fed basal diet (8.1% fat and 0.04% cholesterol by weight), and the remainder were fed challenge diet (17.7% fat and 0.61% cholest ...	1992	1627618
care and breeding of the gray, short-tailed opossum (monodelphis domestica)		1991	1658456
ontogeny of the thymus gland of a marsupial (monodelphis domestica).	the gray short-tailed opossum (monodelphis domestica) has recently been established as a laboratory animal; consequently, its utility as an animal model is enhanced as more of its basic biologic characteristics become defined. to this end, we studied the ontogeny of the thymus gland in m. domestica ranging in age from the day of birth to over three years. in contrast to most australian marsupials, m. domestica possesses only a thoracic thymus. the thymus is large in neonates and remains large un ...	1991	1658459
the intact central nervous system of the newborn opossum in long-term culture: fine structure and gaba-mediated inhibition of electrical activity.	1. the entire central nervous system (cns) of the newly born, south american opossum (monodelphis domestica) was isolated and maintained in basal medium, eagle's (bme) with 0.2% foetal calf serum and antibiotics. isolated cns preparations remained electrically excitable for up to 10 days. the fine structure of the spinal cord was normal after 5 days in culture: axons, synapses, dendrites and glia were virtually unchanged. signs of degeneration were evident only in dorsal areas of the spinal cord ...	1991	1661773
regulation of gabab receptors by histamine and neuronal activity in the isolated spinal cord of neonatal opossum in culture.	the aim of these experiments has been to analyse the properties of receptors for the transmitter gamma-aminobutyric acid (gaba) in developing mammalian nervous system. changes in responses of gabab receptors have been measured after alterations of the chemical environment and the level of electrical activity. we have previously shown that when the central nervous system (cns) of the new-born opossum, monodelphis domestica, is cultured for three to five days in the presence of histidine, inhibiti ...	1991	1684671
hindiii rflp for nras in monodelphis domestica.		1991	1684857
the origins of supraspinal projections to lumbosacral and cervical levels of the spinal cord in the gray short-tailed brazilian opossum, monodelphis domestica.	retrograde tracing techniques were used to identify supraspinal neurons that project to sacral, lumbar and cervical levels of the spinal cord in the gray short-tailed brazilian opossum, monodelphis domestica. injections of fast blue, true blue or wheat germ agglutinin conjugated to horseradish peroxidase into the sacral or lumbar cord labeled neurons in hypothalamic and brainstem nuclei reported to innervate the same levels in other mammals. injections at cervical levels produced extensive label ...	1991	1684917
entrainment of circadian phase in developing gray short-tailed opossums: mother vs. environment.	in a marsupial species, the gray short-tailed opossum (monodelphis domestica), the suprachiasmatic nuclei (scn), the site of a circadian clock, are formed postnatally and begin oscillating as a circadian clock on day 20. in this study, we examined how the timing (phase) of the scn clock in the developing opossum is coordinated to the environmental light-dark cycle. when pups were reared from birth in darkness by intact dams, the circadian phases in scn metabolic activity (monitored by 2-deoxy-d- ...	1990	1698034
dna damage is involved in the induction of opacification and neovascularization of the cornea by ultraviolet radiation.	studies were conducted to examine ultraviolet radiation (uvr)-induced alterations of the cornea of the gray, short-tailed opossum. monodelphis domestica, and the effect of post-uvr illumination to photoreactivation light (prl, 320-500 nm). as photoreactivation treatment specifically monomerizes pyrimidine dimers, an amelioration of the uvr-induced biological end-point would implicate dna as being a primary chromophore for induction of that end-point. corneas of anesthetized, four-month-old, opos ...	1991	1709874
restoration of conduction and growth of axons through injured spinal cord of neonatal opossum in culture.	the ability of neurons in the central nervous system to grow through a lesion and restore conduction has been analyzed in a developing spinal cord. the preparation consists of the entire central nervous system of the newly born opossum (monodelphis domestica), isolated and maintained in culture. cell division, cell migration, and reflexes are maintained in such preparations for up to 8 days in culture. in the present experiments, massive lesions were produced by crushing the spinal cord, which a ...	1992	1729714
photoreactivation of ultraviolet radiation-induced skin and eye tumors of monodelphis domestica.	chronic exposure of the opossum monodelphis domestica to uv radiation (uvr) leads to the formation of cutaneous and corneal tumors. groups of shaved opossums were exposed 3 times/week to: (a) uvr alone; (b) uvr followed immediately by 1 h of photoreactivating light (prl) (320-700 nm); (c) 1 h of prl followed by uvr; and (d) 1 h of prl alone. exposures were terminated after 70 weeks of treatment. analysis of data plotted as probability of tumor formation versus weeks from first exposure shows tha ...	1991	1742727
milk composition in an american marsupial (monodelphis domestica).	1. twenty one sequential milk samples from an american marsupial (monodelphis domestica) were analyzed. 2. the solids fraction was relatively low initially (10% w/w) and then increased to about 30% at mid-lactation where it remained until lactation ceased. 3. during the first 50 days of lactation the relative proportions of protein, fat and carbohydrate were 36, 28 and 34%, respectively, of the solids fraction. 4. sodium and magnesium concentrations were constant; however levels of potassium and ...	1991	1769214
monodelphis domesticus: a model for early developmental wound healing.	fetuses heal significantly differently than adults; amniotic fluid and the fetal environment have profound effects on the fetus' response to excisional wounding. the brazilian gray short-tailed opossum (monodelphis domesticus) is presented as a new model for early developmental wound healing. this is a small, docile, pouchless marsupial whose young, at birth, are equivalent to an 8-week gestational age human, which allows investigations of early developmental wound healing exclusive of the amnio ...	1991	1772223
production of interleukin-1 in a south american opossum (monodelphis domestica).	a homologous thymocyte costimulatory assay using thymocytes from a south american opossum (monodelphis domestica) detected and measured interleukin-1 (il-1). opossum il-1 was obtained from lipopolysaccharide-stimulated macrophage and skin cultures and its molecular weight was determined to be 15,000 to 17,000. opossum il-1 did not stimulate proliferation of murine thymocytes; conversely, neither human nor murine il-1 stimulated opossum thymocytes. anti-human il-1 antibodies were also not reactiv ...	1991	1773863
ontogeny of cholecystokinin-like immunoreactivity in the brazilian opossum brain.	we have studied the anatomical distribution of cholecystokinin-like immunoreactive (cck-ir) somata and fibers in the brain of the adult and developing brazilian short-tailed opossum, monodelphis domestica. animals ranged in age from the day of birth (1pn) to young adulthood (180pn). a nickel enhanced, avidin-biotin, indirect immunohistochemical technique was used to identify cck-ir structures. somata containing cck immunoreactivity were observed in the cerebral cortex, hippocampus, hypothalamus, ...	1991	1786635
ontogeny of cells containing estrogen receptor-like immunoreactivity in the brazilian opossum brain.	in this study, we have used the brazilian short-tailed opossum (monodelphis domestica) as a model to study the ontogeny of estrogen receptors in the mammalian brain. monodelphis is a small, pouchless marsupial which breeds well under laboratory conditions and whose young are born in an immature sexually undifferentiated state. the abbott h222 monoclonal rat estrogen receptor antibody (gift of abbott laboratories) was utilized in an indirect immunohistochemical procedure to detect estrogen recept ...	1991	1790590
the development of enamel tubules during the formation of enamel in the marsupial monodelphis domestica.	in monodelphis domestica, although both processes from odontoblasts and projections from ameloblasts were found in developing enamel, the majority of the contents of enamel tubules were probably processes that originated from odontoblasts. processes from odontoblasts penetrating into enamel touched part of the ameloblasts in the stage of enamel formation. no specialised cell junctions were seen at the adherence between the two. there were no enamel tubules in the aprismatic and pseudoprismatic e ...	1991	1817141
cellular immune response of a marsupial, monodelphis domestica.	marsupials are interesting subjects for studies of comparative and developmental immunology because they separated from eutherian mammals over 100 million years ago and because the newborns are still in a fetal state. we studied cellular immunity in a fully pedigreed colony of the marsupial, m. domestica (commonly called the gray short-tailed opossum). peripheral blood lymphocytes were separated on nylon wool columns into adherent cells bearing surface immunoglobulin (b cells) and nonadherent ce ...	1991	1829419
localization of cells containing estrogen receptor-like immunoreactivity in the brazilian opossum brain.	the brazilian opossum (monodelphis domestica) is a small, pouchless marsupial whose young are born in an immature, sexually undifferentiated state. etgen and fadem, and handa and coworkers have biochemically detected and characterized estrogen receptors in the forebrain of the brazilian opossum. in this study, we have examined the distribution of estrogen receptor-like immunoreactive (er-li) cells in the brains of gonadectomized male and female brazilian opossums using abbott h222 rat monoclonal ...	1991	1855151
aldehyde dehydrogenase (aldh) isozymes in the gray short-tailed opossum (monodelphis domestica): tissue and subcellular distribution and biochemical genetics of aldh3.	polyacrylamide gel isoelectric focusing (page-ief), cellulose acetate electrophoresis, and histochemical techniques were used to examine the tissue and subcellular distribution, genetics and biochemical properties of aldehyde dehydrogenase (aldh) isozymes in a didelphid marsupial, the gray short-tail opossum (monodelphis domestica). at least 14 zones of activity were resolved by page-ief and divided into five isozyme groups and three aldh classes, based upon comparisons with properties previousl ...	1991	1859355
changes in actin distribution during sperm development in the opossum, monodelphis domestica.	the distribution of actin in spermatogenic cells and epididymal spermatozoa of the opossum, monodelphis domestica, was examined by immunofluorescence microscopy to identify its potential function in the major structural events of sperm development. in spermatogenic cells actin was located at the site of initial interaction between the nucleus and acrosome and remained present through subsequent acrosome morphogenesis. actin was also associated both with the posterior pole of the nucleus, at the ...	1991	1867397
macroscopic and histologic study to differentiate large glands and bulbi in the perianal body region of the male gray short-tailed opossum, monodelphis domestica.	on either side of the cloaca of the male monodelphis domestica, there is a large pack of globular structures lying between the external skin and the ischial arch. the structures within each of these bilateral complexes can be classified into three groups. group 1 comprises different kinds of glands. there are two large glands, "paraproctic glands" according to schaffer (1940), whose spacious cavity is bounded by a secretory epithelium. the secretion is holocrine in a way that cells are shed into ...	1991	1883869
[the hypophysis of monodelphis domestica (marsupialia): the state of organ development and cell differentiation in the adenohypophysis on different days post partum].	in the newborn gray short-tailed opossum, monodelphis domestica, the fusion of the neurohypophysis and adenohypophysis has not finished. a compression of the adenohypophyseal vesicle is exerted by the neurohypophysis. the latter, as can be seen in a 12-day old specimen, finally, will be almost completely wrapped into the adenohypophysis. the adenohypophysis of the newborn and early pouch-young shows substantial growing on the basis of mitoses mainly in the pars intermedia, but in the pars distal ...	1991	1889364
mammary glands in male marsupials. 2. development of teat primordia in didelphis virginiana and monodelphis domestica.	young and adults of both sexes of two didelphid marsupials, didelphis virginiana and monodelphis domestica, were examined externally for evidence of mammary gland development. female young possessed teat numbers typical of adult females (13-15 in d. virginiana; 11-13 in m. domestica). male young showed variable teat numbers which were always low compared with females, with the majority possessing 2-4 in anterior positions. teats were also present in adult males of both species, in similar number ...	1991	1947228
characterization and distribution of estrogen receptors in the diencephalon of the gray short-tailed opossum.	the brazilian gray short-tailed opossum is a pouchless marsupial whose young are born sexually undifferentiated making this animal ideal for developmental studies. previously, etgen and fadem (dev. brain res., 49 (1989) 131-133; gen. comp. endocrinol., 66 (1987) 441-446) detected estrogen receptor (er) in the hypothalamus-preoptic area, and compared males and females in the adult and during development. in this study we characterized the er and determined its distribution in specific diencephali ...	1991	2015504
ultraviolet radiation-induced skin tumors in a south american opossum (monodelphis domestica).	a total of 19 male and 21 female south american opossums (monodelphis domestica) were exposed to 250 j/m2 ultraviolet radiation from fs-40 sunlamps (280-400 nm) three times weekly for 70 weeks. the backs of the opossums were shaved as necessary to remove hair. in order to prevent photoreactivation of ultraviolet radiation-induced pyrimidine dimers by the light-dependent photolyase enzyme of the opossum, ultraviolet radiation-exposed opossums were housed under red lights (600-800 nm). the opossum ...	1991	2017828
[the topography of the abdominal organs of monodelphis domestica (marsupialia)].	30 adult animals (14 females, 16 males) were studied macroscopically. the main findings are as follows: 1. the intestine is without striking macroscopic features that characterize the different parts of it. a variation of position of ileum, cecum, and colon, respectively, is due to the length of their mesenteries. 2. in adult males, the intestines are displaced from their position in the caudal part of the abdomen by the urethra (the urethral diameter is even wider than that of the gut, because ...	1990	2082622
mammary glands in male marsupials: i. primordia in neonatal opossums didelphis virginiana and monodelphis domestica.	neonates of the american didelphid marsupials didelphis virginiana and monodelphis domestica were sexed by karyotype and histologically examined on the day of birth. mammary anlagen were found in both sexes of both species, but the neonatal males had less than one-third of the full female complement of mammary glands. male neonates of both species also had paired scrotal bulges anterior to the genital tubercle but these were never present in females, once again raising the question of whether th ...	1990	2133544
age effects on hematologic and serum chemical values in gray short-tailed opossums (monodelphis domestica).	hematologic and serum chemical values were determined in groups of gray short-tailed opossums (monodelphis domestica) that differed in age by increments of 6 months throughout the normal adult lives of m. domestica in captivity (6 months to 3.5 years). significant age related differences were observed for some characteristics in both sexes. previously reported sex differences in hematologic characteristics were confirmed. the means, ranges and standard deviations for the values presented here ca ...	1990	2157102
the luteinizing hormone-releasing hormone (lh-rh) system in neonatally estradiol-feminized male gray short-tailed opossums (monodelphis domestica).	in this study, the luteinizing hormone-releasing hormone (lh-rh) system was examined in adult gray short-tailed opossums that had been treated with estradiol benzoate (eb) on days 1 and 3 of postnatal life, a treatment which results in complete block of testicular development. the finding that the organization of the lh-rh system in neonatally eb-treated males did not differ from that of neonatally untreated animals indicates that the lh-rh system can develop normally despite the absence of gona ...	1990	2190714
synaptology of luteinizing hormone-releasing hormone (lhrh)-immunoreactive cells in the nervus terminalis of the gray short-tailed opossum (monodelphis domestica).	light and electron microscopic immunocytochemistry were used to examine the structure of lhrh neurons and fibers in the nervus terminalis of the gray short-tailed opossum (monodelphis domestica). lhrh-immunoreactive neurons and fibers form a loose plexus within the fascicular network of the ganglion terminale on the median surface of the olfactory bulb. there are at least two populations of lhrh-immunoreactive neurons within the network of the ganglion terminale: fusiform and round neurons simil ...	1990	2193040
chicken gnrh ii occurs together with mammalian gnrh in a south american species of marsupial (monodelphis domestica).	two molecular forms of gonadotropin-releasing hormone (gnrh) were demonstrated in hypothalamic extracts of m. domestica using high performance liquid chromatography and radioimmunoassay with specific gnrh antisera. one form eluted in the same position as synthetic mammalian gnrh and was quantified equally by two mammalian gnrh antisera, while the second form coeluted with synthetic chicken gnrh ii and was quantified equally with two chicken gnrh ii antisera. the finding of chicken gnrh ii in a s ...	1990	2199949
reflexes, fictive respiration and cell division in the brain and spinal cord of the newborn opossum, monodelphis domestica, isolated and maintained in vitro.	1. the entire central nervous system (cns) was isolated from 1- to 4-day-old newborn south american opossums (monodelphis domestica). at this stage the cns has only an embryonic forebrain (two-layered) and no cerebellum and corresponds to a 14-day rat embryo. its eyes, ears and hind-limbs are only at an early stage of formation. the isolated cns preparations continue to develop and to produce electrical signals for up to 4 days in oxygenated krebs' fluid at 23 degrees c. 2. the longitudinal axis ...	1990	2230634
genetics of alcohol dehydrogenase and aldehyde dehydrogenase from monodelphis domestica cornea: further evidence for identity of corneal aldehyde dehydrogenase with a major soluble protein.	a didelphid marsupial, the gray short-tailed opossum (monodelphis domestica), was used as a model species to study the biochemical genetics of alcohol dehydrogenases (adhs) and aldehyde dehydrogenase (aldh) in corneal tissue. isoelectric point variants of corneal aldh (designated aldh3) and a major soluble protein in corneal extracts were observed among eight families of animals used in studying the genetics of these proteins. both phenotypes exhibited identical patterns following page-ief and w ...	1990	2272517
the effects of gonadal hormones on scent marking and related behavior and morphology in female gray short-tailed opossums (monodelphis domestica).	the hormonal control of scent marking and related behavior and morphology was examined in female gray short-tailed opossums. females rarely scent marked when intact or following ovariectomy. testosterone (t) but not estradiol (e) treatment stimulated chest marking while either hormone stimulated head marking in ovariectomized females tested alone. when the same females were tested with males, t-treated females showed little scent marking of any type; e-treated females showed hip marking in signi ...	1990	2286362
organization and postnatal development of zebrin ii antigenic compartmentation in the cerebellar vermis of the grey opossum, monodelphis domestica.	the mammalian cerebellar cortex consists of a number of parasagittal purkinje cell compartments that can be demonstrated cytochemically. the afferent inputs to the cerebellum are also compartmentalized, and a complex but reproducible relationship exists between the afferents and the intrinsic maps. developmental studies in the rat have shown that many of the main features of compartmentation are already established at birth, and are therefore not easily manipulated experimentally. the compartmen ...	1990	2298942
naturally occurring malignant melanoma in the south american opossum (monodelphis domestica).		1990	2309386
cgrp-like immunoreactivity in sensory nerve endings of the golgi tendon organ. a light- and electron-microscopic study in the grey short-tailed opossum (monodelphis domestica).	using light- and electron-microscopic immunohistochemistry, it was shown that primary sensory nerve endings in golgi tendon organs of the grey short-tailed opossum (monodelphis domestica) contain immunoreactivities to a polyclonal antibody directed against calcitonin gene-related peptide (cgrp). myelinated afferent axons (6-9 microns in diameter) of the golgi tendon organs stained moderately for cgrp. sensory nerve endings within the sensory compartment of the golgi tendon organs displayed elect ...	1990	2349873
photoreactivation of cyclobutane dimers and (6-4) photoproducts in the epidermis of the marsupial, monodelphis domestica.	radioimmunoassays were used to investigate the repair of cyclobutane pyrimidine dimers and pyrimidine (6-4)pyrimidone photoproducts ((6-4] photoproducts) in the epidermis of the south american opossum, monodelphis domestica. in the absence of photoreactivating light, both types of photodamage were excised with similar kinetics, 50% of the damage remaining 8 h after uv irradiation in vivo. exposure of uv-irradiated skin to photoreactivating light resulted in removal of most of the cyclobutane dim ...	1990	2367561
the cytoskeletal system of mammalian primitive erythrocytes: studies in developing marsupials.	seeking to resolve conflicting literature on cytoskeletal structure in mammalian "primitive" generation erythrocytes, we have utilized the circulating blood of developing marsupials. in young of the tammar wallaby (macropus eugenii) and the gray short-tailed opossum (monodelphis domestica), relatively large, nucleated primitive erythrocytes constituted nearly 100% of the circulating population at birth (= day 0) and in fetuses (tammar) several days before birth. these cells were discoidal or ell ...	1990	2376068
immunohistochemical localization of cholecystokinin in the medial preoptic area and anterior hypothalamus of the brazilian gray short-tailed opossum: a sex difference.	we have studied the anatomical localization of cholecystokinin-like immunoreactivity (cck ir) in somata and fibers in the medial preoptic area (mpa) and anterior hypothalamus (ah) of the brazilian gray short-tailed opossum, (monodelphis domestica). with the aid of an avidin-biotin, nickel-enhanced, immunohistochemical technique, cck ir neuronal elements were found within the mpa and ah. a large number of cck ir cell bodies were located in the mpa of colchicine-treated opossums. the mpa also cont ...	2008	2394987
gonadal sex differentiation in the neonatal marsupial, monodelphis domestica.	a quantitative and histological study of the gonads of newborn grey short-tailed opossums, monodelphis domestica, is described. the pups were karyotyped, and comparisons were made within litters segregating for xx and xy sex chromosomes. a total of four litters including 25 pups were available. on the day of birth, developing testes were significantly larger than the ovaries of litter mates, and testes could be histologically distinguished by the formation of sex cords and a tunica albuginea. th ...	1990	2401220
thermogenic capabilities of the opossum monodelphis domestica when warm and cold acclimated: similarities between american and australian marsupials.	1. monodelphis domestica is a small marsupial mammal from south america. its thermogenic abilities in the cold were determined when the opossums were both warm (wa) and cold (ca) acclimated. maximum heat production of m. domestica was obtained at low temperatures in helium-oxygen. 2. basal metabolic rate (bmr) in the wa animals was 3.2 w/kg and mean body temperature was 32.6 degrees c at 30 degrees c. these values were lower than those generally reported for marsupials. nevertheless, these m. do ...	1988	2450718
the morphogenesis of the posterior neural tube and tail in monodelphis domesticus.	the process of secondary neuralation has been studied in the brazilian opossum, monodelphis domesticus. secondary neuralation in this mammal was found to have qualities of secondary neuralation that were present in both the chick and the mouse. in this study, four stages of secondary neuralation were found beginning with the medullary cord stage. other stages in the differentiation of the secondary neural tube were: differentiation of the neuroepithelium, cavitation of the medullary cord, and pr ...	1989	2505824
identification of the molecular target for the suppression of contact hypersensitivity by ultraviolet radiation.	this study was conducted to explore the involvement of dna damage in the suppression of contact hypersensitivity (chs) by uv irradiation. the opossum, monodelphis domestica, was used because cells of these marsupials have an enzyme that is activated by visible light (photoreactivating enzyme) and repairs ultraviolet radiation (uvr)-induced pyrimidine dimers in dna. a single dose of 1,500 j/m2 of uvb (280-320 nm) radiation, representing 2 minimal erythema doses, was administered to the dorsal ski ...	1989	2529340
genetic variation in adenylate kinase 1, glyceraldehyde-3-phosphate dehydrogenase, and glutamic-pyruvate transaminase in the marsupial monodelphis domestica.		1989	2560631
limb defects in gray short-tailed opossums (monodelphis domestica) following postnatal injection with ethanol or saline.	because the hindlimbs of marsupials at birth are in an embryonic stage of development, this group can prove useful for studies of limb teratology. in this study, injection of neonatal gray opossums with 2 mg ethanol (etoh) or saline (sal) in the right or left hindquarter resulted in defects of the associated limb in 44% of etoh animals and 16% of sal animals. affected sal animals showed gait abnormalities, foot clubbing, and moderately reduced limb size. affected etoh animals showed these abnorm ...	1989	2567065
comparative biochemistry of hepatic arylsulfatases from north and south american opossums.	1. the virginia opossum (didelphis virginiana) possessed an arylsulfatase which had a relative molecular weight of 130 +/- 12 kda, displayed anomalous kinetics, hydrolysed aa2s, and exhibited other properties of arylsulfatase a. no arylsulfatase b was found. 2. the arylsulfatase present in the gray short-tailed opossum (monodelphis domestica) had a relative molecular weight of 56 +/- 4 kda, exhibited linear kinetics, was inhibited by chloride, and possessed other characteristics of arylsulfatase ...	1989	2574650
monodelphis domestica (grey short-tailed opossum): an accessible model for studies of early neocortical development.	the development of the neocortex of the marsupial monodelphis domestica has been studied from birth until adulthood. monodelphis is born after a gestational period of 14 days, a time when the neocortex is still at a two-layered "embryonic" stage of development, that is equivalent to a 13-14 day rat embryo or 6 week human embryo. the cortical plate does not begin to appear until 3 to 5 days postnatal. thus the whole of neocortical development is a postnatal phenomenon in this species, as has been ...	1989	2596703
acid phosphatase polymorphism in a laboratory marsupial, monodelphis domestica.		1989	2627200
proteins in cerebrospinal fluid and plasma of postnatal monodelphis domestica (grey short-tailed opossum).	1. the protein composition and concentrations of total protein in cerebrospinal fluid (csf) and plasma of opossum (monodelphis domestica) from birth until adulthood have been estimated. 2. total protein in csf increased from birth to a peak concentration between 5 and 10 days (500 mg/100 ml) after which it declined rapidly. 3. total protein in plasma started at a low level at birth (below 400 mg/100 ml) and increased progressively to the adult value (8500 mg/100 ml). 4. proteins identified in cs ...	1989	2706945
ultraviolet radiation--induced malignant melanoma in monodelphis domestica.	several lines of evidence support the hypothesis that ultraviolet radiation (uvr) is involved in the etiology of cutaneous melanoma in humans. however, progress in understanding the mechanisms involved in induction of melanotic tumors by uvr has been hindered by lack of a suitable animal model. during the course of multiple exposures (3 times/wk for 70 wk) of the south american opossum, monodelphis domestica, to uvr, we first observed the appearance of areas of dermal melanocytic hyperplasia (mh ...	1989	2762379
immune response of a marsupial (monodelphis domestica) to sheep red blood cells.	a study of the humoral immune response of a marsupial, monodelphis domestica, was performed using sheep red blood cells as the immunogen and a hemolytic titration as the assay. the primary response to a single intramuscular injection was similar to that observed in other mammalian species, except that the titers remained high for as long as 37 weeks after the initial injection. the secondary response was weaker than the primary response and diminished as early as 15 weeks after the initial injec ...	1989	2767312
ontogeny of estrogen binding sites in the brain of gray short-tailed opossums (monodelphis domestica).	this study evaluated the binding of [3h]estradiol to brain cytosols from gray short-tailed opossums ranging in age from newborn to 63 days postnatal. estrogen binding was undetectable in whole-brain cytosol of newborn opossums. by postnatal day 4, high affinity (kd = 0.2 nm), saturable (bmax = 3 fmol/mg protein) estrogen binding sites were present, and estrogen binding in whole-brain remained low but detectable (2-5 fmol/mg) through day 63. in contrast, estrogen binding sites in the hypothalamus ...	1989	2791259
the hormonal control of scent marking and precopulatory behavior in male gray short-tailed opossums (monodelphis domestica).	little is known about the hormonal control of behavior in marsupials. in the present study, the effects of castration and of testosterone or estradiol replacement therapy on scent marking and precopulatory behavior in male gray short-tailed oppossums (monodelphis domestica) were examined. it was found that castration resulted in decreases in chest and flank/hip marking displayed by male gray opossums. testosterone but not estradiol stimulated chest marking in castrates. males treated with either ...	1989	2793079
the effects of pheromonal stimuli on estrus and peripheral plasma estradiol in female gray short-tailed opossums (monodelphis domestica).	exposure to male pheromones is associated with the activation of vaginal estrus in gray short-tailed opossums. the effects of such exposure on peripheral plasma estradiol-17 beta (e) levels in this marsupial species were examined in this study. mean e levels of 27.8 pg/ml +/- 4.4 in diestrous females living in a room containing only females were similar to those seen in other marsupials. direct naso/oral exposure to pheromonal cues provided by males resulted in vaginal estrus in 75% of these fem ...	1989	2804214
photoreversal of the ultraviolet radiation-induced disappearance of atpase-positive langerhans cells in the epidermis of monodelphis domestica.	the present study was undertaken to explore the possible causes of ultraviolet radiation (uvr)-induced disappearance of atpase-positive, epidermal langerhans cells (lc). monodelphis domestica was used because it has the capacity for photoreactivation of uvr-induced pyrimidine dimers in epidermal dna. single, 330 j/m2 (ears) or 500 j/m2 (back) uvr exposures (fs-40 sunlamps) reduced the numbers of atpase-positive epidermal lc in m. domestica ears to approximately 15% of those in unirradiated ears ...	1988	2973509
immunocytochemical localization of luteinizing hormone-releasing hormone (lhrh) in the brain and nervus terminalis of the adult and early neonatal gray short-tailed opossum (monodelphis domestica).	luteinizing hormone-releasing hormone (lhrh) was detected by immunocytochemical procedures in cells and fibers in the brain and in the nervus terminalis of the adult and neonatal gray, short-tailed opossum (monodelphis domestica). as in several species of eutherian mammals, lhrh-immunoreactive cells and fibers were seen in the medial septal nuclei, nucleus, and tract of the diagonal band and olfactory tubercle. surprisingly, few lhrh-immunoreactive cells were found in the hypothalamus or in the ...	1988	3056990
an evaluation of three anaesthetic regimes in the gray short-tailed opossum (monodelphis domestica).	the effect of several anaesthetic agents on the gray short-tailed opossum (monodelphis domestica) was investigated. pentobarbitone sodium at a dose of 50 mg/kg sedated the animals but did not produce analgesia or anaesthesia. a combination of ketamine hydrochloride and xylazine at 40 mg/kg and 5 mg/kg, respectively, sedated the animals, but anaesthetic levels were not attained. halothane was most effective in producing anaesthesia in monodelphis domestica. hypothermia was a major side effect wit ...	1988	3172709
transplantation, growth, and regression of mouse melanoma xenografts in neonatal marsupials.	marsupials are useful for cancer research since they are born in a fetal stage of development with little immunologic competence. in this study, mouse melanoma xenografts were grown in neonatal gray opossums (monodelphis domestica) injected at 12-32 days of age. tumors appeared between 1 and 3 weeks postinjection and at least 73% of tumor-bearing animals rejected their tumors. initiation of tumor growth was rare in animals over 24 days of age and, in most cases, tumors size peaked at about 50 da ...	1988	3179772
anatomic and functional development of the suprachiasmatic nuclei in the gray short-tailed opossum.	the anatomic and functional development of the suprachiasmatic nuclei (scn) was studied in the gray short-tailed opossum, monodelphis domestica. to provide a background for developmental studies, daily patterns of wheel-running behavior and scn metabolic activity were studied in adult animals. adult opossums manifested robust circadian rhythms in locomotor activity that were entrained by the daily light-dark cycle. the temporal course of scn metabolic activity, studied by the 14c-labeled deoxygl ...	1988	3183724
reproduction, development and physiology of the gray short-tailed opossum (monodelphis domestica).	the gray short-tailed opossum (monodelphis domestica) has become a useful marsupial for biomedical research since it breeds reliably in the laboratory. during a 3 year period (1983-1986), a total of 129 litters were born in the colony at njms resulting in five generations of captive-born animals. litter size ranged from 2 to 13 and the average sex ratio at weaning was 1:1. mean body temperature of m. domestica was approximately 32.3 degrees c and respiratory rate approximately 54 breaths/minute. ...	1987	3312806
the immunocytochemical localization of luteinizing hormone-releasing hormone in the brain of the gray short-tailed opossum (monodelphis domestica).		1987	3329468
photorepair of ultraviolet radiation-induced pyrimidine dimers in corneal dna.	the induction and photorepair of pyrimidine dimers in dna have been measured in the ultraviolet-irradiated, corneal epithelium of the marsupial, monodelphis domestica, using damage-specific nucleases from micrococcus luteus in conjunction with agarose gel electrophoresis. we observed that fs-40 sunlamps (280-400 nm) induced 7.2 +/- 1.0 x 10(-5) pyrimidine dimers per kilobase (kb) of dna per j/m2. following 100 j/m2, 50% and greater than 90% of the dimers were photorepaired during a 10- and 30-mi ...	1988	3386657
[the angular process of monodelphis domestica (didelphidae, marsupialia) and its relation to the middle ear: an ontogenetic and evolutionary morphologic study].	in most marsupials, the angular process is inflected medially. by using an ontogenetic series of monodelphis domestica, the development of this characteristic structure has been described. in contrast with the eutherian mammals, in marsupials there is retained a close connection between the dentale and the tympanicum and goniale; it is well known that these 2 elements of the middle ear are derived from the angulare and prearticulare of the reptilian lower jaw. at the neonatal stage, the dentale ...	1987	3569814
estrogen binding macromolecules in hypothalamus-preoptic area of male and female gray short-tailed opossums (monodelphis domestica).	estrogen binding sites in the hypothalamus-preoptic area (hpoa) of adult male and female gray opossums (monodelphis domestica) were characterized by incubating cytosols from gonadectomized animals with [3h]estradiol (e2) in the presence or absence of excess unlabeled e2. scatchard analyses revealed that hpoa cytosols from both males and females contained high concentrations (25-30 fmol/mg protein) of binding sites with a very high affinity (kd = 0.08-0.12 nm) for e2. there was no sex difference ...	1987	3609714
the oocyte of a new world marsupial, monodelphis domestica: structure, formation, and function of the enveloping mucoid layer.	ovulated oocytes of the gray short-tailed opossum monodelphis domestica are surrounded by a thin zona pellucida and are devoid of a cumulus oophorus. in the ampulla of the oviduct, oocytes acquire a thick mucoid layer composed of concentrically arranged fibrillar material. exocytosis by the secretory cells of the oviductal epithelium occurs in the region of the oviduct adjacent to the egg. this suggests that the oocyte-zona-mucus layer complex may influence the oviductal epithelium to secrete. d ...	2013	3612053
monodelphis domestica: a new animal model for studies in photodermatology.		2013	3628511
loss of photoreversibility of sunburn cell induction in monodelphis domestica.		1987	3628517
hair growth induction by ultraviolet radiation in the marsupial monodelphis domestica.	hair follicles in the telogen stage of the hair cycle were induced into anagen phase after the skin of the south american opossum, monodelphis domestica, was exposed to levels of ultraviolet b radiation (280 to 320 nm), which induced desquamation. post-ultraviolet b exposure to long-wavelength radiation (320 to 400 nm, ultraviolet a) suppressed the induction of edema and desquamation and the induction of hair growth. hair growth induction was also observed in skin damaged either by mechanical ab ...	1987	3631981
neural modulation of cutaneous differentiation: epidermal hyperplasia and precocious hair development following partial neuralectomy in opossum pups.	the original intent of the present study was to evaluate the compensatory response of the nervous system to areas of denervation. a portion of the spinal cord in the lumbosacral region of one-day opossum pups (monodelphis domesticus) was removed by cauterization. this partial neuralectomy produced an expected compensatory response of neurons in the dorsal root ganglia, but in addition produced unexpected abnormalities of cutaneous differentiation. at 4-6 days following surgery, an increase in th ...	1987	3670733
uv radiation-induced skin tumors in monodelphis domestica.	chronic exposure of the skin of the south american opossum (monodelphis domestica) to ultraviolet radiation (uvr) from an fs-40 sunlamp (280-400 nm) 3 times per week for a total of 200 exposures resulted in the appearance of actinic keratoses, fibrosarcomas, squamous cell carcinomas and keratoacanthomas. at the higher doses of uvr used in this study, moderate to severe hyperplasia was also observed. the susceptibility of this animal to the induction of skin tumors by uvr in conjunction with the ...	1987	3684736
inhibition of testicular development and feminization of the male genitalia by neonatal estrogen treatment in a marsupial.	differentiation of the mammalian gonad is thought to be constitutive, occurring independently of and not significantly altered by gonadal hormones. in this study, estradiol benzoate (eb) and testosterone propionate (tp) were administered to newborn gray opossums (monodelphis domestica) during the first week after birth. it was found that males and females treated with tp and females treated with eb developed normally. in males treated with eb on both day 1 and day 3 of postnatal life, gonads did ...	1986	3708056
nest-building in gray short-tailed opossums: temperature effects and sex differences.	the effects of ambient temperature and of sex on nest-building behavior were studied in a laboratory colony of gray short-tailed opossums, small, brazilian marsupials. at 24 degrees c, both males and females used more nesting material and built larger nests of better quality than at 27 degrees c. although both males and females built nests using the mouth, forelegs, hindlegs and tail, females built nests more reliably at the higher temperature and used more nesting material than males at both te ...	1986	3714839
passively acquired immunity in the newborn of a marsupial (monodelphis domestica).	a colony of fully pedigreed monodelphis domestica has been used to investigate the maternal-fetal relationship in this unique marsupial species. to determine how immunity is transferred from mothers to young in m. domestica, we hyperimmunized females with sheep red blood cells (srbc) before and during gestation. offspring from these females were collected at various times after birth, and saline extracts of the neonates were assayed for hemolysins against srbc. antibodies were present in extract ...	1986	3752338
dietary effects on hematologic and serum chemical values in gray short-tailed opossums (monodelphis domestica).	at the time of weaning (8 weeks), 57 gray short-tailed opossums (monodelphis domestica) were placed in four dietary groups. one group was fed a horsemeat-based diet that had been used for 2.5 years in our colony, and three groups were fed three different commercial fox food diets. after the animals had reached sexual maturity (6 months), blood samples were collected and subjected to standard hematologic and serum chemical assays. significant differences were observed among the dietary groups and ...	2013	3754293