| gonadal sex differentiation in embryos and neonates of the marsupial, monodelphis domestica: arrest of testis development in postterm embryos. | growth and histological differentiation were studied in 8 litters of embryos and 4 litters of neonate grey short-tailed opossums, monodelphis domestica. the embryonic litters included 2 that had passed their expected birth date, and whose weights exceeded the usual birthweights; we refer to these litters as 'postmature'. there was an abrupt increase in the growth rate of xy gonads after birth, but this was not seen in xx gonads. although there was evidence of testicular differentiation in xy gon ... | 1993 | 8376201 |
| development of connections by axons growing through injured spinal cord of neonatal opossum in culture. | the ability of neurites to grow through a lesion and form synaptic connections has been analyzed in a developing mammalian spinal cord in vitro. after isolation of the entire central nervous system (cns) of the newly born south american opossum (monodelphis domestica) the spinal cord was crushed. outgrowth through and beyond the lesion was observed in living preparations for 2-5 days by staining axons with carbocyanine dyes. the structure of the acute crush and the growing neurites was examined ... | 1993 | 8478604 |
| a high-resolution banding pattern idiogram of monodelphis domestica chromosomes (marsupialia, mammalia). | | 1993 | 8485993 |
| the sensory innervation of the periodontium of the third premolar in monodelphis domestica. | location and structure of sensory nerve endings in the periodontium of the third premolar in monodelphis domestica have been investigated by means of light and electron microscopy. the periodontal cleft of the tooth is apically enlarged. the number of nerve endings increases towards apex. three types of sensory nerve endings have been observed: free nerve endings, ruffini nerve endings and lamellated corpuscles. free nerve endings could only be identified by electron microscopy. ruffini nerve en ... | 1993 | 8434506 |
| the sensory innervation of the gingiva and mucosa in monodelphis domestica: an ultrastructural study. | the location and structure of sensory nerve endings was examined in the mucosa and in the gingiva propria adjacent to the third premolar of monodelphis domestica by light and electron microscopy. the mucous membrane of the gingiva propria is covered with a stratified keratinized squamous epithelium. the mucous membrane of the adjacent inner aspect of the lip and of the vestibulum oris were covered with a nonkeratinized squamous epithelium. free nerve endings, merkel nerve endings and lamellated ... | 1993 | 8434505 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| onset of neocortical synaptogenesis in neonatal monodelphis domestica (south american grey short-tailed opossum). | | 1992 | 1557699 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| care and breeding of the gray, short-tailed opossum (monodelphis domestica) | | 1991 | 1658456 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| naturally occurring malignant melanoma in the south american opossum (monodelphis domestica). | | 1990 | 2309386 |
| [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 |
| acid phosphatase polymorphism in a laboratory marsupial, monodelphis domestica. | | 1989 | 2627200 |
| genetic variation in adenylate kinase 1, glyceraldehyde-3-phosphate dehydrogenase, and glutamic-pyruvate transaminase in the marsupial monodelphis domestica. | | 1989 | 2560631 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| loss of photoreversibility of sunburn cell induction in monodelphis domestica. | | 1987 | 3628517 |
| 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 |
| 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 |
| 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 |
| characterization of oestrus and timed collection of oocytes in the grey short-tailed opossum, monodelphis domestica. | a system of test-pairing was used to detect reproductive behaviour in the grey short-tailed opossum. this enabled timing and characterization of the development of pro-oestrous and oestrous behaviour, and facilitated collection of ovulated and unovulated oocytes. oestrus was induced 8.5 days (n = 80, 95% confidence limits 7.56-9.21) after the introduction of a male. timed examination of the ovaries by laparotomy indicated that ovulation occurred 14-16 h after the first onset of oestrous behaviou ... | 1987 | 3820163 |
| [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 |
| the immunocytochemical localization of luteinizing hormone-releasing hormone in the brain of the gray short-tailed opossum (monodelphis domestica). | | 1987 | 3329468 |
| 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 |
| the effects of diet on growth and reproduction in gray short-tailed opossums (monodelphis domestica). | in order to develop standard conditions for rearing the gray short-tailed opossum, monodelphis domestica, as a potentially useful experimental laboratory animal, the effects of four different diets on growth and reproduction were assessed. one diet was a meat-based diet prepared in the laboratory. the other three diets were commercially produced fox foods designated reproduction diet, lactation diet, and growing and furring diet. all pairs of m. domestica fed the reproduction diet produced at le ... | 1985 | 4056701 |
| ultraviolet radiation-induced histopathologic changes in the skin of the marsupial monodelphis domestica. ii. quantitative studies of the photoreactivation of induced hyperplasia and sunburn cell formation. | induction of sunburn cells (sbcs) and hyperplasia of the epidermis of the marsupial monodelphis domestica by ultraviolet radiation (uvr) has been studied. a dose of 500 j/m2 (approximately 1 minimal erythemal dose) from an fs-40 sunlamp induced measurable numbers of sbcs with a peak number at 32-48 h post-uvr exposure of skin to photoreactivating light suppressed the induction of sbcs by approximately 75%. pre-uvr exposure to photoreactivating light had no effect on the induction of sbcs. induct ... | 1985 | 4045223 |
| evidence for the activation of female reproduction by males in a marsupial, the gray short-tailed opossum (monodelphis domestica). | although social factors are known to influence reproduction in a number of eutherian mammals, the effect of these factors on marsupial reproduction has not heretofore been studied. in this study, the temporal pattern of births and of the appearance of vaginal estrus following pairing with a male were examined in the gray short-tailed opossum, a small brazilian didelphid. although the estrous cycle is approximately 32 days long in this species, 75% of conceptions occurred within 9 days and 91.6% ... | 1985 | 4063435 |
| ultraviolet radiation-induced histopathological changes in the skin of the marsupial monodelphis domestica. i. the effects of acute and chronic exposures and of photoreactivation treatment. | post-ultraviolet radiation (uvr) treatment of the south american opossum, monodelphis domestica with long-wavelength radiation (320-400 nm) suppressed the induction of histopathological alterations in the skin. this study identifies dna as a primary chromophore involved in the induction of various photobiological responses of the skin such as hyperplasia and sunburn cell formation, and also identified pyrimidine dimers as one responsible dna lesion. the histology of skin from opossums exposed to ... | 1985 | 4027189 |
| photoreactivation of uv-induced pyrimidine dimers and erythema in the marsupial monodelphis domestica. | post-uv treatment of the gray, short-tailed opossum monodelphis domestica with photoreactivating light (320-400 nm) suppressed the appearance of uv-induced erythema as evidenced by an increase in the dose of uv required to elicit an erythemal response. the average erythema dose for animals held in the dark following uv exposure was 620 +/- 40 j/m2, whereas 2460 +/- 110 j/m2 were required for erythema induction with animals exposed to 90 min of photoreactivating light post-uv. pre-uv exposure to ... | 1985 | 3857591 |
| characteristics of the oestrous cycle and influence of social factors in grey short-tailed opossums (monodelphis domestica). | characteristics of the oestrous cycle of grey short-tailed opossums were studied by vaginal smears. the period of oestrus was identified by a sudden proliferation of epithelial cells which lasted about 6 days (range 3-12 days), followed by a leucocytic infiltration. oestrous cycle length showed a bimodal distribution of 14.4 days (5 cycles, range 11-17 days) and 32.3 days (10 cycles, range 28-39 days). females housed with males showed more days of epithelial cell proliferation than did females h ... | 1985 | 4039362 |
| early differentiation of the afferent nervous system in glabrous snout skin of the opossum (monodelphis domesticus). | early differentiation of afferent fibers innervating the snout skin of monodelphis domesticus was studied by electron microscopy and by light-microscopic silver staining techniques. this study was undertaken to investigate the relationship between dermal and epidermal innervation in the neonate opossum while correlating these findings with behavioral responses. the advantage of using this species is that the neonate is born in a very immature stage and has a rostrocaudal development of the perip ... | 1985 | 3835670 |
| photorepair of pyrimidine dimers in the epidermis of the marsupial monodelphis domestica. | | 1984 | 6483989 |
| differential nor activities in somatic and germ cells of monodelphis domestica (marsupialia, mammalia). | somatic and germ cells of the gray short-tailed opossum (monodelphis domestica) were analyzed cytogenetically by c-banding, g-banding, and silver staining. the diploid chromosome number was found to be 18. c-banding revealed constitutive heterochromatin at the centromeres of all chromosomes, with additional heterochromatin on one arm of the y. silver staining for the localization of nucleolus organizer regions (nors) showed nors on the x and on a pair of autosomes, tentatively designated as chro ... | 1983 | 6617263 |
| skin structure in newborn marsupials with focus on cutaneous gas exchange. | a morphological and morphometric study of the skin of a variety of newborn marsupials (dasyurus viverrinus, monodelphis domestica, trichosurus vulpecula, isoodon obesulus, perameles nasuta, phascolarctos cinereus, potorous tridactylus, petrogale penicillata, thylogale thetidi, macropus dorsalis) and of a monotreme hatchling (ornithorhynchus anatinus) was undertaken to assess the possibility of cutaneous gas exchange. additionally, the lungs of some of these species were investigated to assess it ... | 2018 | 29947022 |
| mining and functional verification of calcitonin genes from the genome database. | with more countries in the world entering elderly society, osteoporosis is a common disease among the elderly, especially middle-aged and elderly women. although calcitonin is an effective drug used to treat osteoporosis in clinical practice, it also exists such problems as high cost, short half-life, and high immunogenicity. therefore, to explore more efficient calcitonin has important clinical significance. | 2018 | 29745315 |
| resistance of south american opossums to vwf-binding venom c-type lectins. | opossums in the clade didelphini are well known to be resistant to snake venom due to endogenous circulating inhibitors which target metalloproteinases and phospholipases. however, the mechanisms through which these opossums cope with a variety of other damaging venom proteins are unknown. a protein involved in blood clotting (von willebrand factor) has been found to have undergone rapid adaptive evolution in venom-resistant opossums. this protein is a known target for a subset of snake venom c- ... | 2020 | 32135198 |
| the embryo of the silky shrew opossum, caenolestes fuliginosus (tomes, 1863): first description of the embryo of paucituberculata. | the development of caenolestid marsupials (order paucituberculata) is virtually unknown. we provide here the first description of caenolestes fuliginosus embryos collected in the colombian central andes. our sample of four embryos comes from a single female caught during a fieldtrip at río blanco (manizales, caldas), in 2014. the sample was processed for macroscopic description using a standard event system and for histological descriptions (sectioning and staining). the grade of development of ... | 2020 | 31984547 |
| parotid salivary gland basal cell adenocarcinoma in a big-eared opossum (didelphis aurita). | the opossum (family didelphidae) is a marsupial endemic to the americas. apart from the south american short-tailed opossum (monodelphis domestica) and the virginia opossum (didelphis virginiana), there is considerable lack of knowledge about the health and diseases of most opossum species. among these, the big-eared opossum (didelphis aurita) is found in argentina, brazil and paraguay. natural and experimental studies have shown this species to be susceptible to infectious agents with zoonotic ... | 2018 | 29599001 |
| the rod signaling pathway in marsupial retinae. | the retinal rod pathway, featuring dedicated rod bipolar cells (rbcs) and aii amacrine cells, has been intensely studied in placental mammals. here, we analyzed the rod pathway in a nocturnal marsupial, the south american opossum monodelphis domestica to elucidate whether marsupials have a similar rod pathway. the retina was dominated by rods with densities of 338,000-413,000/mm². immunohistochemistry for the rbc-specific marker protein kinase cα (pkcα) and the aii cell marker calretinin reveale ... | 2018 | 30157204 |
| uterine epithelial remodelling during pregnancy in the marsupial monodelphis domestica (didelphidae): implications for mammalian placental evolution. | mammalian pregnancy involves remodelling of the uterine epithelium to enable placentation. in marsupials, such remodelling has probably played a key role in the transition from ancestral invasive placentation to non-invasive placentation. identifying uterine alterations that are unique to marsupials with non-invasive placentation can thus elucidate mechanisms of marsupial placental evolution. we identified apical alterations to uterine epithelial cells prior to implantation in monodelphis domest ... | 2020 | 32052440 |
| identification of a novel antisense noncoding rna, alid, transcribed from the putative imprinting control region of marsupial igf2r. | genomic imprinting leads to maternal expression of igf2r in both mouse and opossum. in mouse, the antisense long noncoding (lnc) rna airn, which is paternally expressed from the differentially methylated region (dmr) in the second intron of igf2r, is required to silence the paternal igf2r. in opossum, however, intriguingly, the dmr was reported to be in a different downstream intron (intron 11) and there was no antisense lncrna detected in previous analyses. therefore, clarifying the imprinting ... | 2018 | 30268152 |
| downregulation of trkc receptors increases dendritic arborization of purkinje cells in the developing cerebellum of the opossum, monodelphis domestica. | in therian mammals, the cerebellum is one of the late developing structures in the brain. specifically, the proliferation of cerebellar granule cells occurs after birth, and even in humans, the generation of these cells continues during the first year of life. the main difference between marsupials and eutherians is that the majority of the brain structures in marsupials develop after birth. herein, we report that in the newborn laboratory opossum (monodelphis domestica), the cerebellar primordi ... | 2020 | 33013328 |
| bone biomarkers in koalas: validation of assays and preliminary analyses. | traumatic injury, including bone fracture, is, to date, one of the leading causes of koala mortality in the south east queensland region of australia. further, the specialist diet of koalas, which is restricted to certain eucalyptus spp., may impact their normal bone physiology. considering the dramatic koala population decline and high incidence of trauma, a greater understanding of koala bone physiology may support conservation. we retrieved from genbank the protein sequences of parathyroid ho ... | 2020 | 32917121 |
| gene expression profiling of postnatal lung development in the marsupial gray short-tailed opossum (monodelphis domestica) highlights conserved developmental pathways and specific characteristics during lung organogenesis. | after a short gestation, marsupials give birth to immature neonates with lungs that are not fully developed and in early life the neonate partially relies on gas exchange through the skin. therefore, significant lung development occurs after birth in marsupials in contrast to eutherian mammals such as humans and mice where lung development occurs predominantly in the embryo. to explore the mechanisms of marsupial lung development in comparison to eutherians, morphological and gene expression ana ... | 2018 | 30290757 |
| rodents and other small mammal reservoirs in plague foci in northeastern brazil. | plague is an acute, infectious zoonotic disease, primarily of wild rodents and their fleas, that affects humans and other mammals. in brazil, several plague foci are located in the northeast region. plague surveillance based on monitoring of rodents was discontinued in 2007, and the current information on rodent populations is unsatisfactory. our purpose was to update the information on rodents and other small mammals in plague foci in northeastern brazil. | 2017 | 30943181 |
| trunk movements during locomotion in the marsupial monodelphis domestica (didelphidae). | the small didelphid cmarsupial, monodelphis domestica, uses a lateral sequence walk during slow treadmill locomotion and gradually shifts to a trot as speed increases. at higher speeds it changes abruptly to a half-bound. cinematographic records suggest significant lateral bending but no sagittal bending of the trunk during the slow walk and a reduced amount of lateral bending during the fast walk. there is slight lteral, but no sagittal, bending during the trot. sagittal bending is obvious duri ... | 1992 | 29865578 |
| ticks, rickettsial and erlichial infection in small mammals from atlantic forest remnants in northeastern brazil. | we evaluated infection by rickettsia spp. and ehrlichia spp in small mammals and their ticks from two atlantic forest conservation areas in the state of rio grande do norte, northeastern brazil. a total of 39 small mammals were captured during 2012-2013, encompassing 33 marsupials (29 didelphis albiventris, four monodelphis domestica), three cricetidae rodents (two necromys lasiurus, one rattus rattus), one caviomorpha rodent (thrichomys apereoides) and two armadillos (euphractus sexcinctus). th ... | 2018 | 30370217 |
| helicobacter monodelphidis sp. nov. and helicobacter didelphidarum sp. nov., isolated from grey short-tailed opossums (monodelphis domestica) with endemic cloacal prolapses. | in a search for potential causes of increased prolapse incidence in grey short-tailed opossum colonies, samples from the gastrointestinal tracts of 94 clinically normal opossums with rectal prolapses were screened for helicobacter species by culture and pcr. forty strains of two novel helicobacter species which differed from the established helicobacter taxa were isolated from opossums with and without prolapses. one of the helicobacter species was spiral-shaped and urease-negative whereas the o ... | 2020 | 33079029 |
| j. p. hill and katherine watson's studies of the neural crest in marsupials. | in the early part of the 20th century, j. p. hill and k. p. watson embarked on a comprehensive study of the development of the brain in australian marsupials. their work included series from three major groups: dasyurids, peramelids, and diprotodonts, covering early primitive streak through brain closure and folding stages. while the major part of the work was on the development of the brain, in the course of this work they documented that cellular proliferations from the neural plate provided m ... | 2020 | 32960453 |
| a single-cell transcriptome atlas of marsupial embryogenesis and x inactivation. | single-cell rna sequencing of embryos can resolve the transcriptional landscape of development at unprecedented resolution. to date, single-cell rna-sequencing studies of mammalian embryos have focused exclusively on eutherian species. analysis of mammalian outgroups has the potential to identify deeply conserved lineage specification and pluripotency factors, and can extend our understanding of x dosage compensation. metatherian (marsupial) mammals diverged from eutherians around 160 million ye ... | 2020 | 32814901 |
| identification of regenerative processes in neonatal spinal cord injury in the opossum (monodelphis domestica): a transcriptomic study. | this study investigates the response to spinal cord injury in the gray short-tailed opossum (monodelphis domestica). in opossums spinal injury early in development results in spontaneous axon growth through the injury, but this regenerative potential diminishes with maturity until it is lost entirely. the mechanisms underlying this regeneration remain unknown. rna sequencing was used to identify differential gene expression in regenerating (sci at postnatal day 7, p7sci) and nonregenerating (sci ... | 2020 | 32710567 |
| opossum mammary maturation as it relates to immune cell infiltration and nutritional gene transcription. | the mammary gland has evolved to accommodate the developmental needs of offspring in species-specific ways. this is particularly true for marsupials. marsupial milk content changes dramatically throughout lactation in ways appearing timed with neonatal ontogeny and behavior. here we investigate morphological restructuring within the mammaries throughout lactation in the gray short-tailed opossum, monodelphis domestica. substantial remodeling of the mammaries occurs throughout the first half of a ... | 2020 | 32551417 |
| opossum cathelicidins exhibit antimicrobial activity against a broad spectrum of pathogens including west nile virus. | this study aimed to characterize cathelicidins from the gray short-tailed opossum in silico and experimentally validate their antimicrobial effects against various pathogenic bacteria and west nile virus (wnv). genome-wide in silico analysis against the current genome assembly of the gray short-tailed opossum yielded 56 classical antimicrobial peptides (amps) from eight different families, among which 19 cathelicidins, namely modocath1 - 19, were analyzed in silico to predict their antimicrobial ... | 2020 | 32194564 |
| experimental infection of monodelphis domestica with rickettsia parkeri. | this study aimed to evaluate the infection of the marsupial monodelphis domestica (the gray short-tailed opossum) by rickettsia parkeri and its role as an amplifier of the bacterium for amblyomma ticks. ten m. domestica males were inoculated with phosphate-buffered saline (pbs) and 106 vero cells infected with r. parkeri. in seven animals, inoculation was intramuscular, and in three intraperitoneal. one male (control) received 1 ml of the same vehicle used for inoculation intraperitoneally. the ... | 2020 | 31883908 |
| evidence for regulation of the complement system during pregnancy being ancient and conserved in mammals. | here we demonstrate that regulation of the complement (c') components of the immune system is an ancient and conserved feature of mammalian pregnancy. transcript levels were reduced for complement components c3 and c4 throughout pregnancy in a marsupial, monodelphis domestica. downstream c' component transcripts were significantly less abundant relative to non-pregnant controls at the start of pregnancy but increased during late pregnancy, in some cases peaking close to parturition. these result ... | 2020 | 31785265 |
| cooperative inflammation: the recruitment of inflammatory signaling in marsupial and eutherian pregnancy. | the evolution of viviparity in therian mammals, i.e. marsupials and "placental" mammals, occurred by retention of the conceptus in the female reproductive tract and precocious "hatching" from the shell coat. both eutherian embryo implantation and the opossum embryo attachment reaction are evolutionarily derived from and homologous to a defensive inflammatory process induced after shell coat hatching. however, both lineages, marsupials and placental mammals, have modified the inflammatory respons ... | 2020 | 31783286 |
| aged opossums show alterations in spatial learning behavior and reduced neurogenesis in the dentate gyrus. | in many mammalian species including opossums, adult neurogenesis, the function of which is not completely understood, declines with aging. aging also causes impairment of cognition. to understand whether new neurons contribute to learning and memory, we performed experiments on young and aged laboratory opossums, monodelphis domestica, and examined the association between spatial memory using the morris water maze test and the rate of adult neurogenesis in the dentate gyrus (dg). modification of ... | 2019 | 31780889 |
| influence of biological sex on social behavior, individual recogntion, and non-associative learning in the adult gray short-tailed opossum (monodelphis domestica). | social behavior is critical for relationship formation and is influenced by myriad environmental and individual factors. basic and preclinical research typically relies on rodent models to identify the mechanisms that underlie behavior; however, it is important to use non-rodent models as well. a major objective of the present study was to test the hypothesis that biological sex and social experience modulate the expression of social behavior in the adult gray short-tailed opossum (monodelphis d ... | 2019 | 31465782 |
| sequence alteration in the enhancer contributes to the heterochronic sox9 expression in marsupial cranial neural crest. | neonates of marsupial mammals are altricial at birth, because their gestation period is relatively short compared to placental mammals. yet, as they need to travel to the teat from the birth canal, and suckle on the mother's milk, forelimbs and jaws develop significantly early. previous studies in opossum (monodelphis domestica), an experimental marsupial model, have revealed that cranial neural crest cells are generated significantly early compared to those in placental mammals, such as mouse, ... | 2019 | 31430446 |
| progesterone signaling during pregnancy in the lab opossum, monodelphis domestica. | to investigate subtle pregnancy-associated changes in the lab opossum, monodelphis domestica, an induced ovulator, we compared pregnant with non-pregnant and pseudopregnant animals with regard to serum p4 levels and progesterone receptor (pr) expression. using video-verified, time-mated lab opossums as sources of biological material, we compared ovaries, uteri and sera obtained on odd-numbered days of the 14.5-day pregnancy in this animal. females that mated successfully but did not produce embr ... | 2019 | 31254723 |