PMID(sorted ascending)
a study of steroid 11beta-hydroxylation by adrenal mitochondria of marsupials--part ii. the effect of corticotrophin, metopirone and ph on 11beta-hydroxylation of 11-deoxycortisol and 17alpha-oh-progesterone by adrenal mitochondria of possum (trichosurus vulpecula). 197824136
the organization of the facial nucleus of the brush-tailed possum (trichosurus vulpecula).the facial nucleus of the brush-tailed possum has been studied using nissl staining and the horseradish peroxidase (hrp) retrograde tracing technique. in nissl stained sections the nucleus is seen to comprise five distinct subnuclei. injections of hrp into individual facial muscle groups have shown that these subnuclei reflect the peripheral innervation pattern of efferents from this nucleus. although in most cases, injection of hrp into a single facial muscle group resulted in the labelling of ...197765363
the auditory midbrain of a marsupial: the brush-tailed possum (trichosurus vulpecula).a microelectrode survey was made of the midbrain auditory nuclei of the brushtailed possum (trichosurus vulpecula), a common australian marsupial. information was sought on the tuning characteristics of individual neurones, tonotopic organization and mechanisms of sound localization. it was felt that such information would be of use in future studies of the development and evolution of mammalian hearing. twelve possums were anaesthetized with ketamine and chloralose-urethane, and recordings were ...1978208715
aspects of laterality in the marsupial trichosurus vulpecula (brush-tailed possum). 1977280202
changes in steroid biosynthesis by adrenal homogenates of the possum (trichosurus vulpecula) at various stages of sexual maturation with special reference to 5 beta-reductase activity. 1977299622
a study of steroid 11beta-hydroxylation by adrenal mitochondria of marsupials--part i. a comparision of 11beta-hydroxylase activity and specificity for different steroid substrates by possum (trichosurus vulpecula), kangaroo (macropus major) and beef. 1977304122
observations on the secretions of the subcommissural organ and the pineal in the adult brush-talled possum (trichosurus vulpecula).secretory functions of the subcommissural organ (sco) were investigated using mainly transmission and scanning electron microscopes, in 40 adult (19 males, 21 females) trichosurus vulpecula which were caught in different seasons over several years. there is clear evidence of apical secretion, reissner's fiber (rf), a presumptive basal secretory material with associated perivascular space and labyrinthine basal lamina. secretory function does not appear to be related to the sex of the animal or t ...1979440531
metabolism and defluorination of fluoroacetate in the brush-tailed possum (trichosurus vulpecula).the brush-tailed possum (t. vulpecula) from western australia was found to be nearly 150 times more resistant to fluoroacetate intoxication in vivo than the same species from south australia. acetone powder preparations from the liver of animals from both populations showed similar abilities to convert fluoroacetate into fluorocitrate. aconitate hydratase activity in liver preparations from both western australian and south australian animals was similarly and competitively inhibited by fluoroci ...1979485974
a serological survey of australian wildlife for antibodies to leptospires of the hebdomadis serogroup.a serological survey for antibodies to leptospira interrograns serovar hardjo was conducted on 574 serum samples from 10 native and 4 introduced wildlife species in south-eastern australia. the microscopic agglutination (ma) test was used, and titres to hardjo antigen were detected in 33.5% of 352 brushtailed possums (trichosurus vulpecula) sampled in several areas of victoria. prevalence of reactors ranged from 14 to 66% in 4 populations examined intensively. serovar balcanica was isolated from ...1979485984
a sero-epidemiological study of leptospira interrogans serovar balcanica in four brush-tailed possum populations in victoria, australia.the microscopic agglutination (ma) test was utilised to study the prevalence of antibodies to leptospira interrogans serovar hardjo in 4 populations of brush-tailed possums (trichosurus vulpecula). the overall antibody prevalence varied from 14% to 66%; however, the age distribution of ma test titres was remarkably similar in all 4 populations. antibody prevalence was similar in both males and females and demonstrable antibodies were limited to sexually mature animals. the greater prevalence of ...1979485985
expression of pgk-a in the australian brush-tailed possum, trichosurus vulpecula (kerr), consistent with paternal x extensive survey of erythrocytes of marsupials other than kangaroos for electrophoretic variation if x-linked enzymes revealed two rare pgk-a phenotypes in the phalangerid trichosurus vupecula and one in trichosurus caninus. four putatively heterozygous females expressed only the variant allelic isozyme in some tissues but expressed a trace of the normal isozyme in others. a putatively hemizygous male expressed only the variant isozyme in all tissues. the phenotypic patterns were consistent w ...1979486075
the subcommissural organ of the adult and pouch-young brush-tailed possum (trichosurus vulpecula). a scanning electron microscopic study. 1979509507
ratio of inferior olivary cells to purkinje cells in a marsupial (trichosurus vulpecula).an indirect estimate of the extent of branching of the olivary axons in the cerebellum in a marsupial (trichosurus vulpecula) was carried out. the cells in the inferior olivary nuclear complex (ioc) of both sides were estimated (mean = 57,200), as were the cerebellar purkinje cells (mean = 881,300). assuming that all climbing fibers arise from ioc cells and that each purkinje cell receives a climbing fiber input, each ioc cell sends climbing fiber terminals to 15 purkinje cells.2004525234
experimental infections of brush-tailed possums, common wombats and water rats with leptospira interrogans serovars balcanica and hardjo.of 12 brush-tailed possums (trichosurus vulpecula) inoculated with leptospira interrogans serovar balcanica 11 developed migroagglutination (ma) antibody to jardjo antigen by 14 days postincubation (pi). leptospiruria was observed in 2 possums 117 to 145 days pi. of 6 possums inoculated with serovar hardjo 4 developed low short-lived titres by day 18 pi. two of 3 wombats (vombatus ursinus) inoculated with balcanica had high ma titres (greater than or equal to 1:128) by day 16 pi and leptospiruri ...1979533478
the organization of neocortical projections from the ventrolateral thalamic nucleus in the brush-tailed possum, trichosurus vulpecula, and the problem of motor and somatic sensory convergence within the mammalian brain.the retrograde transport of hrp was used to determine the extent and organizational details of the vl neocortical projection in trichosurus. the major, or external, part of vl projects homotypically to the anteromedial part of the parietofrontal cortex, overlapping the vp cortical projection field extensively, but not completely. overlap between the vl field and smi is most extensive in the area of rear limb representation, and decreases considerably in the area of the head representation. a sma ...1979536306
a scanning electron microscope study of the pineal recess of the adult brush-tailed possum (trichosurus vulpecula).the ventricular surface features of the pineal recess of 35 adult brush-tailed possums (trichosurus vulpecula) were studied, mainly with the scanning microscope. the complex and interesting details observed have not been reported before. the pineal recess shows three distinct zones, and it is suggested that these be called: central, paracentral, and peripheral. the surface cells of the central zone show neither cilia nor microvilli, the paracentral zone shows microvilli (in a polygonal and homog ...1979541240
marsupial cells in long-term culture.cell lines have been developed from several species of australian marsupials and studied during long-term growth. cell lines developed from macropodid skin or heart tissues all had reproducible finite life-spans. however, cell lines developed from dasyurids showed bariable behavior in culture: lines developed from antechinus stuartii and dasyurus viverrinus had finite life-spans, while lines developed from sminthopsis crassicaudata had indefinite life-spans. s. crassicaudata lines usually became ...1977559639
isolation of leptospira interrogans, serotype balcanica from a brush-tailed opossum (trichosurus vulpecula) 1977612328
the number and distribution of ganglion cells in the retina of the brush-tailed possum, trichosurus vulpecula.the distribution of ganglion cells in the retina of the adult brush-tailed possum was determined by light microscopy of nissl stained retinal whole mounts. qualitatively, the distribution in this marsupial retina shows features, such as an area centralis and a visual streak, which are found separately or together in eutherian mammals. the possum retina is avascular and the eye has a weak tapetum in the superior fundus.the retinal area is 260 mm2 and there are about 280,000 ganglion cells. the di ...1978624790
the optic nerve of the brush-tailed possum, trichosurus vulpecula: fibre diameter spectrum and conduction latency groups.the principal findings of this report on the morphology and electrophysiology of the possum optic nerve are: (i) there are about 230,000 fibres in the optic nerve. this fibre count, based on electron microscopy, is slightly less than a previously reported estimate of the total number of ganglion cells in the possum retina. (ii) the majority (greater than 98%) of the fibres of the optic nerve are myelinated axons of retinal ganglion cells. the diameters of these fibres range from 0.4--4.6 microme ...1978641234
the retinal origins of the optic nerve conduction latency groups in the brush-tailed possum, trichosurus vulpecula. 1978641235
an atlas of the dorsal thalamus of the marsupial brush-tailed possum, trichosurus several respects the dorsal thalamus of trichosurus presents a level of organizational complexity considerably in advance of that seen in didelphis. in particular, such features as the lamination of the dorsal lateral geniculate, the distinct subdivisions of the ventroposterior and lateroposterior complexes, and the more pronounced separation of the ventroanterior from the ventrolateral nucleus, are similar to conditions found in many eutherians. on the other hand, some features which trichos ...1978670061
altered retinal projections in brushtailed possum, trichosurus vulpecula, following removal of one eye. 1978681552
the organization of neocortical projections from the ventroposterior thalamic complex in the marsupial brush-tailed possum, trichosurus vulpecula: a horseradish peroxidase study.retrograde transport of horseradish peroxidase (hrp) was used to determine the extent and some of the organizational details of the cortical projection of the ventroposterior thalamic complex (vp) in the marsupial brush-tailed possum, trichosurus vulpecula. the cortical projection field of vp is coincident with si as determined by electrophysiological methods, and would appear not to overlap fully the primary motor cortex. thus, in trichosurus it appears that the motor and somatic sensory cortic ...1978689987
the effect of intravenous infusion of angiotensin ii on drinking in the australian marsupial trichosurus vulpecula.1. when marsupial brush-tailed possums were maintained on a normal fruit and vegetable diet with access to water ad libitum, i.v. infusion of synthetic angiotensin ii at rates of 0.035-3.5 mug/kg. min caused short-latency drinking in up to seven of eleven animals tested. these rates also had significant pressor effects.2. there was a positive correlation between the rate of angiotensin infusion and the percentage of tested animals which responded by drinking, as well as the amount of water drunk ...1978690940
prostatic function in the brush-tailed possum, trichosurus vulpecula. 1978690986
the serologic and cultural prevalence of leptospira interrogans serovar balcanica in possums (trichosurus vulpecula) in new a serologic and cultural survey of 127 brush-tailed possums (trichosurus vulpecula) occupying pasture land in new zealand, leptospires of the hebdomadis serogroup were obtained from 48 (38%) of the animals sampled. eight isolates were identified by cross-absorption agglutin ation studies as being leptospira interrogans serovar balcanica. there was a marked age difference in prevalence with 41 positive cultures from 64 mature adults (64%) and no recoveries being made from juveniles. isolation ...1978691129
morphological variation in the brain of the marsupial brush-tailed possum, trichosurus vulpecula.the brush-tailed possum, trichosurus vulpecula, displays an unusual amount of phenotypic variation within its central nervous system. these variations are expressed in terms of gross brain morphology, as evidenced by the occurrence of both highly lissencephalic and gyrencephalic neocortices in apparently normal adult animals; by displacement and asymmetry of certain internal structures, notably within the ventral thalamic nuclei; and by the inconstant occurrence of at least one cell group within ...1978737529
ultrastructure of glomerulus in trichosurus vulpecula (possum). 1978755173
nonrandom sex-chromosome association and constitutive heterochromatin in the brush-tailed possum, trichosurus vulpecula (marsupialia: phalangeridae).nonrandom associations between the short arms of the sex chromosomes of six trichosurus vulpecula were studied in 455 cells from the spleen and bone marrow. the association occurs in both sexes and was found to be independent of age. there was, however, a significant difference in the degree of association between the two tissues studied. regions of constitutive heterochromatin were found to be located in the short arms of the x and y chromosomes by using a c-banding technique. nucleolar organiz ...1977862434
morphology and histochemistry of the mandibular gland of the australian brush-tail possum trichosurus vulpecula (marsupialia).a histological, ultrastructural and histochemical study of the mandibular gland of the australian possum trichosurus vulpecula revealed essentially similar features as those described earlier for the mandibular gland of the taxonomically relatively unrelated american opossum didelphis. the secretory endpieces consist of a branched tubular part, composed of serous cells whose secretion granules contain neutral glycoproteins, and terminal acini, consisting of seromucous cells containing small amou ...1977900527
ultrastructural changes in spermatozoa of the brush-tailed possum, trichosurus vulpecula (marsupialia), during epididymal transit. part ii: the acrosome.the acrosome in spermatozoa from the caput epididymidis of the australian brush-tailed possum, trichosurus vulpecula, typically forms a cup-like structure, sitting on the anterior third of the dorsal surface of the nucleus. the base of the acrosomal 'cup' is narrowly separated from the nuclear surface, while the body of the 'cup' projects voluminously away from the nucleus. during epididymal transit these pronounced marginal extensions of the acrosome are retracted towards the nucleus, and the e ...1976963735
spermiogenesis in the brush-tailed possum, trichosurus vulpecula (marsupialia). the development of the acrosome.acrosome development in the australian brush-tailed possum, trichosurus vulpecula, displays a number of extraordinary features. this is particularly evident in the later stages of spermiogenesis, when the area of the nuclear surface bounded by the nuclear ring, and covered by the acrosome, is reduced considerable. as a result, the acrosomal material becomes located over its definitive position on the anterior third of the dorsal nuclear surface; in this process it is thrown into a series of fold ...1976963736
spinocerebellar tracts in the brush-tailed possum, trichosurus vulpecula.the direct projections of the spinal cord onto the cerebellar cortex were traced using nauta method following the placement of cervical or thoracic spinal cord hemisections in six brush-tailed possums. degenerating fibres reached the cerebellum via typically placed dorsal and ventral spinocerebellar tracts. although complete differentiation of the terminations of ventral and dorsal tracts was not possible, it was found that the dorsal tract terminates mainly in the ipsilateral anterior lobe ermi ...1976990905
the features of sperm maturation in the epididymis of a marsupial, the brushtailed possum trichosurus vulpecula.possum spermatozoa undergo a distinctive process of maturation in the epididymis, as shown by change in the properties of the sperm surface, by modification of their morphology and by their increasing capacity for progressive motility. modification of the sperm surface over the head and tail is demonstrated by the different affinities of sperm from successive regions of the epididymis for fitc-conjugated wheat germ agglutinin and concanavalin a, and for cationic ferric oxide colloidal particles. ...19761008039
letter: leptospirosis in the opossum (trichosurus vulpecula). 19751060978
letter: isolation of leptospira hardjo from the opossum (trichosurus vulpecula). 19751060979
observations on the ultrastructure of a fiber network in the flagellum of sperm of the blush tailed phalanger, trichosurus vulpecula. 19751090744
steroid formation by the adrenal tissue of the possum (trichosurus vulpecula). 19751122716
experimental gastroesophageal reflux in the australian brush-tailed has been suggested that the lower esophageal sphincter (les) plays an important role in preventing gastroesophageal reflux. this study was designed to determine if abolition of the les alone is sufficient to induce gastroesophageal reflux and esophagitis. studies were performed in the australian brush-tailed possum (trichosurus vulpecula) which has a lower esophagus resembling that of man. esophageal manometry, esophagoscopy, and contrast radiography of the lower esophagus and stomach were pe ...19751158080
uterine response to ovariectomy during the proliferative and luteal phases in the marsupial, trichosurus vulpecula.the uterine luteal phase in t. vulpecula is not dependent upon the secretions of the cl throughout its duration. ablation of the cl or ovariectomy after day 7 of the 26-day oestrous cycle does not result in the termination of the uterine secretory phase. the dependence of the luteal phase on the secretions of the cl is demonstrated by ablation of the cl or ovariectomy on days 2, 4, 8, 12 and 24 of the oestrous cycle. ablation of the cl before day 8 resulted in the inhibition of the impending lut ...19751167910
ultrastructural changes in spermatozoa of the brush-tailed possum, trichosurus vulpecula (marsupialia), during epididymal transit. part i: the flagellum.during epididymal transit, a fibre network and an array of vesicles develop in the posterior two-thirds of the midpiece in sperm of the brush-tailed possum, trichosurus vulpecula. the fibre network is developed by the time the sperm reach the corpus epididymidis, and is composed of evenly spaced, helically arranged fibres lying immediately beneath the plasma membrane. the angle of these fibrous helices is always counter to that of the underlying mitochondrial helix. separating the fibre network ...19751201595
corticobulbar fibres in the north american opossum (didelphis marsupialis virginiana) with notes on the tasmanian brust-tailed possum (trichosurus vulpecula) and other marsupials.corticobulbar projections have been studied in the american opossum by both degeneration and autoradiographic methods and, for the most part, the results confirm our earlier observations (martin & west, 1967; martin, 1968). however, we have obtained evidence for certain connexions not previously described and have delineated the origin(s) of several connexions more precisely by paying particular attention to the degeneration present at thalamic levels in all cases and by the use of autoradiograp ...19751213949
effect of cortisol on utilization and hepatic release of glucose in the marsupial brush-tailed opossum, trichosurus vulpecula.brush-tailed opossums were prepared surgically with indwelling heatic and jugular venous catheters for blood sampling without disturbance in the conscious state. hepatic extraction of rose bengal was 21 +3 (s.d.) % and hepatic clearance, used as a measure of hepatic blood flow, was 42.5 +7 ml/kg/min. hepatic relaease of new glucose, calculated from the thorias vena caval-hepatic venous difference in glucose specific activity at equilibrium during i.v. infusion of [14c]glucose and hepatic blood f ...19761255041
corticosteroid binding by plasma proteins and the effects of oestrogens in the marsupial brush-tailed opossum, trichosurus vulpecula (kerr).using the techniques of equilibrium dialysis at 36 degrees c and gel filtration at 4 degrees c, a high-affinity, transcortin-like, corticosteroid binding system has been demonstrated in the blood plasma of the marsupial trichosurus vulpecula. the affinity constant for non-albumin binding was 4-018 +/- 1-032 x 10(7) (s.c.) 1/mol for males and 4-046 +/- 0.981 x 10(7) for females. the concentration of non-albumin binding sites was 1-82 +/- 0.76 x 10(-7) mol/1 in males and 1-86 +/- 0-57 x 10(-7) mol ...19761255062
long spinal and pyramidal actions on hindlimb motoneurons of the marsupial brush-tailed possum, trichosurus vulpecula.the existence of descending propriospinal reflex linkages between forelimbs and hindlimbs has been established in the brush-tailed possum (trichosurus vulpecula). in animals under chloralose anesthesia and with intact brain stem, forelimb volleys evoked facilitation of flexor and extensor monosynaptic reflexes of both hindlimbs, more pronounced on the ipsilateral side. powerful inhibition of briefer latency and restricted to ipsilateral flexor digitorum longus (fdl) motoneurons was also brought ...19861255227
proceedings: ultrastructure of the mid-piece of the spermatozoon in the marsupial, trichosurus vulpecula. 19761255593
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 ...19921339855
a light-microscopic immunocytochemical study of the endocrine pancreas in the australian fat-tailed dunnart (sminthopsis crassicaudata).the endocrine pancreas of the australian fat-tailed dunnart (sminthopsis crassicaudata) was investigated by means of immunocytochemistry using the avidin-biotin-peroxidase technique. this was a light microscopic study using this established technique and has not been previously investigated. serial paraffin sections were stained individually with primary antibodies for anti-porcine glucagon, anti-beef pork insulin, anti-human somatostatin, and anti-avian pancreatic polypeptide (app), anti-bovine ...19921352914
the transfer of thyroxine from the mother to the young of the marsupials, the bandicoot (isoodon macrourus) and the possum (trichosurus vulpecula).1. the young of the bandicoot and possum are of similar weight at birth (200-250 mg) but by day 50 post-partum have weights of 100 and 20 g, respectively. the aim of this study was to determine whether the disparate growth rate was associated with a difference in the transfer of thyroxine from mother to young. 2. radioactive thyroxine was injected intramuscularly into the lactating female and 24 hr later a blood sample was obtained from the mother and the pouch young removed. the amount of radio ...19921358508
galanin is more common than npy in vascular sympathetic neurons of the brush-tailed possum.the distribution of galanin (gal) in sympathetic vascular neurons of adult and juvenile brush-tailed possums (trichosurus vulpecula), was examined using double-labelling immunohistochemistry. this was compared with the distribution of neuropeptide y (npy) in the same tissues. immunoreactivity (ir) to galanin was present in the majority (64-99%) of nerve cell bodies in paravertebral sympathetic ganglia, where it mostly co-existed with ir to the catecholamine-synthesizing enzyme, tyrosine hydroxyl ...19921371612
a light-microscopic immunocytochemical study of the endocrine pancreas in the australian brush-tailed possum (trichosurus vulpecula).the endocrine pancreas of the australian brush-tailed possum (trichosurus vulpecula) was investigated by means of immunocytochemistry using the avidin-biotin-peroxidase technique. this was a light microscopic study using this established technique. serial paraffin sections were stained individually with primary antibodies for glucagon, insulin, somatostatin, and pancreatic polypeptide (pp), showing the same islet. cells immunoreactive to glucagon, insulin, somatostatin and pp were found in endoc ...19921380858
the role of photoperiod on the initiation of the breeding season of the brushtail possum (trichosurus vulpecula).the role of photoperiod on the initiation of the breeding season of brushtail possums was investigated in possums housed in three light regimens: a short-day, a natural and a long-day photoperiod. seven possums were housed in a natural photoperiod. four possums were transferred to a short-day photoperiod (10 h light, 14 h dark) and eight possums to a long-day photoperiod (14 h light, 10 h dark) on 22 november, when the daylength was 13.34 h. the first rises in plasma progesterone concentrations ...19921404087
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 ...19921404089
mapping human x-linked genes in the phalangerid marsupial trichosurus vulpecula.we mapped 15 human x-chromosome markers in the common brush-tailed possum, trichosurus vulpecula (kerr), which represents the australian marsupial family phalangeridae. in situ hybridization was used to localize highly conserved human x-linked genes to chromosomes of t. vulpecula diploid lines. ten genes located on the long arm of the human x (human xq genes) all mapped to the possum x chromosome. however, all five genes located on the short arm of the human x (human xp genes) mapped to autosome ...19921427847
biphasic retinal neurogenesis in the brush-tailed possum, trichosurus vulpecula: further evidence for the mechanisms involved in formation of ganglion cell density gradients.we investigated cell generation in the retina of the brush-tailed possum (trichosurus vulpecula) by using tritiated (3h)-thymidine labelling of newly generated cells. animals aged between postnatal day (p) 5 and 85 each received a single injection of 3h-thymidine. following autoradiographic processing, maps of labelled cells were constructed from retinal sections. retinal cell generation takes place in two phases, the first is concluding in the retinal periphery at p53 as the second is seen to c ...19921469115
brain content and plasma concentrations of arginine vasopressin in an australian marsupial, the brushtail possum trichosurus vulpecula.arginine vasopressin (avp) has been identified and quantified in the brain and plasma of the possum using a highly specific radioimmunoassay and high-performance liquid chromatography. large amounts of avp were found in the pituitary (16.3 +/- 0.56 micrograms/pituitary, n = 5) and hypothalamus (398 +/- 82.5 ng/hypothalamus), and significant amounts of avp were also present in the cerebral cortex (26.8 +/- 11.5 ng/cortex). plasma avp concentrations were significantly lower (2.2 +/- 0.45 pg/ml, n ...19921478438
erythromycin and motilin stimulate sphincter of oddi motility and inhibit trans-sphincteric flow in the australian possum.the actions of erythromycin lactobionate and porcine motilin on trans-sphincteric flow and simultaneous sphincter of oddi motility were studied in 15 anaesthetized australian brush-tailed possums (trichosurus vulpecula). erythromycin (25-200 micrograms/kg) and motilin (25-200 ng/kg) were administered as graded doses by close intraarterial injection. trans-sphincteric flow was measured as inflow and outflow. both motilin and erythromycin decreased trans-sphincteric inflow (both p < 0.0001) and ou ...19921484568
motilin and erythromycin enhance the in vitro contractile activity of the sphincter of oddi of the australian brush-tailed possum.erythromycin has been shown to interact with gastrointestinal smooth muscle in a similar manner to motilin, and has been postulated as a motilin receptor agonist. we report that in isolated preparations from the biliary tract of thirty one australian brush-tailed possums (trichosurus vulpecula) erythromycin acts in a similar manner to motilin. in all muscle strips from the sphincter of oddi, prepared in both the circular and longitudinal orientation, both synthetic porcine motilin (10(-10) m-10( ...20061538793
oxytocin receptors in the mammary gland and reproductive tract of a marsupial, the brushtail possum (trichosurus vulpecula).previous studies of marsupial lactation have shown that the milk-ejection reflex changes in sensitivity, being greater in small mammary glands sucked by small pouch young and lesser in larger glands supplying milk to larger young. the involvement of oxytocin receptors in these changes was examined in the brushtail possum trichosurus vulpecula. oxytocin receptors were measured in the mammary glands, uterus, and medial vaginal sacs by radioreceptor assay, using [3h]oxytocin as radioligand. in the ...19911661615
bile acids of marsupials. 2. hepatic formation of vulpecholic acid (1 alpha,3 alpha,7 alpha-trihydroxy-5 beta-cholan-24-oic acid) from chenodeoxycholic acid in a marsupial, trichosurus vulpecula (lesson).free vulpecholic acid (1 alpha,3 alpha,7 alpha-trihydroxy-5 beta-cholan-24-oic) is the major biliary component of the australian opossum (trichosurus vulpecula), accompanied only by a few percent of its taurine conjugate. in order to exclude a microbial involvement in its formation (i.e., secondary origin) four sets of experiments were performed. it was found that a) the level of vulpecholic acid remained unchanged in the bile of opossums fed with neomycin and kanamycin for 7 days prior to bile ...19911753212
stability of the acrosome of the brush-tailed possum (trichosurus vulpecula) and tammar wallaby (macropus eugenii) in vitro and after exposure to conditions and agents known to cause capacitation or acrosome reaction of eutherian spermatozoa.ejaculated spermatozoa from brush-tailed possums and tammar wallabies were washed by a 'swim up' procedure into hanks balanced salt solution (hbss), and then exposed to test solutions. spermatozoa were incubated at 33 degrees c, or room temperature when long-term sperm survival (greater than 10 h) was required. exposure of spermatozoa to calcium ionophore a23187, cyclic nucleotides, phosphoinositide pathway intermediates, lysophospholipids, trypsin or 'capacitating' high ionic-strength medium (3 ...19911847424
whey proteins of the common brushtail possum (trichosurus vulpecula): isolation, characterization and changes in concentration in milk during lactation of transferrin, alpha-lactalbumin and serum albumin.1. transferrin and serum albumin were purified from both whey and serum and alpha-lactalbumin was purified from whey from the common brushtail possum (trichosurus vulpecula). 2. the n-terminal amino acid sequences for transferrin and serum albumin were identical for the proteins from both whey and serum and showed homologies with transferrin or serum albumin from other species. 3. n- and c-terminal regions of possum alpha-lactalbumin were also sequenced and have been compared with wallaby alpha- ...19911868684
spontaneous or experimentally induced formation of a special zone in the adrenal cortex of the adult brush-tailed possum (trichosurus vulpecula).the cytology and ultrastructure of the hypertrophied special zone, which is formed spontaneously in the adrenal cortex of adult female brush-tailed possums (trichosurus vulpecula), was compared to the adrenocortical tissue in adult males in which the special zone, normally absent, was induced following castration alone or by additional treatment with follicle-stimulating hormone (fsh). the special zone in females was situated between the zona fasciculata and the zona reticularis, the latter bein ...19911901439
marsupial possum neurotensin: a unique mammalian regulatory peptide exhibiting structural homology to the avian analogue.neurotensin has been isolated from small intestinal extracts of an australian marsupial, the brush-tailed possum (trichosurus vulpecula). the primary structure was determined as: pglu-leu-his-val-asn-lys-ala-arg-arg-val-tyr-ile-leu. when compared with bovine neurotensin, marsupial possum neurotensin exhibits four amino acid substitutions. his for tyr3, val for glu4 and ala for pro7 are identical with those found in chicken neurotensin. in addition, substitution of pro10 with val is unique among ...19911924896
a simple glycerol-based freezing protocol for the semen of a marsupial trichosurus vulpecula, the common brushtail possum.frozen storage of semen and embryos is now a well established part of the breeding of many eutherian mammals but it has not been applied to marsupials. this paper reports the first successful technique for the frozen preservation of marsupial spermatozoa. semen was collected by electroejaculation under anaesthesia from a pool of five brushtail possums. the ejaculated semen was diluted 1:1 with krebs henseleit ringer, centrifuged at 800 g for 5 min, resuspended in the test cryoprotectant media at ...19911947217
uterine oxytocin receptors in an australian marsupial, the brushtail possum, trichosurus vulpecula.1. oxytocin receptors in the uterus of the brushtail possum (t. vulpecula) were characterized by radioreceptor assay and compared with those of the sheep and rat uterus. 2. a single oxytocin binding site was found with an affinity (kd) and receptor concentration (ro) of 3.0 +/- 0.8 nmol/l and 200 +/- 60 fmol/mg protein, respectively (sem; n = 5). the receptor was stable at -20 degrees c; divalent ions were required for optimum binding. 3. competitive displacement curves with related peptides sho ...19901968806
digesta retention and fibre digestion in brushtail possums, ringtail possums and rabbits.1. mean retention times (mrts) of fluid (marked with co-edta), fine particles (mordanted with yb) and large particles (mordanted with cr) were measured in brushtail possums (trichosurus vulpecula), ringtail possums (pseudocheirus peregrinus) and laboratory rabbits fed semipurified diets. 2. in brushtail possums there were no significant differences in mrt among the three digesta markers. 3. in ringtail possums mrts of the fluid and fine particle markers were approximately twice that of the large ...19901976477
retinal epithelial fine structure in the brush-tailed possum (trichosurus vulpecula).as part of a comparative morphological study, the fine structure of the retinal pigment epithelium (rpe), the choriocapillaris and bruch's membrane (complexus basalis) has been studied by electron microscopy in the brush-tailed possum (trichosurus vulpecula), an australian marsupial. in this species, the rpe consists of a single layer of squamous cells which show numerous shallow basal (scleral) infoldings as well as extensive apical (vitreal) processes enclosing rod outer segments. the epitheli ...19912048742
cholinesterase activity in sensory-nerve endings, capillaries and motor end plates of the facial skin of the brush-tailed possum (trichosurus vulpecula).the facial skin of two adult and one 50-day-old pouch animal of the marsupial mammal trichosurus vulpecula was removed after the animals has been suitably anesthetized and perfused for electron microscopy. small blocks of tissue (1 x 0.5 mm) were cut and incubated in acetylthiocholine iodide substrate for cholinesterase studies. the blocks were then subsequently postfixed in osmium tetroxide. thin sections were cut and stained with lead acetate. specific cholinesterase was found within the nerve ...19902075803
mesotocin in the brain and plasma of an australian marsupial, the brushtail possum (trichosurus vulpecula).oxytocic peptides extracted from the brain and plasma of the brushtail possum, trichosurus vulpecula, were separated by reverse-phase high pressure lipid chromatography (hplc) and quantified by specific radioimmunoassays for oxytocin (ot) and mesotocin (mt). the pituitary, hypothalamus and cerebral cortex were found to contain mt only in quantities of 3.9 +/- 0.2 (se) ug, 17.6 +/- 0.6 ng and 21.0 +/- 2.6 ng respectively. the plasma concentration of mt varied according to the degree of stress of ...19902082200
metabolic effects of cortisol, acth, adrenalin and insulin in the marsupial sugar glider, petaurus breviceps.the effects of cortisol, acth, adrenalin and insulin on indices of carbohydrate, fat and protein metabolism were investigated in the conscious marsupial sugar glider petaurus breviceps. short-term i.v. infusion of cortisol at dose rates of 0.02, 0.2 and 1.0 mg/kg per h caused the plasma glucose concentration to rise sharply from the normal range of 3.3-4.4 to 8.1-8.7 mmol/l at the end of the infusion period without significant alteration in plasma free fatty acid (ffa), amino acid or urea concen ...19902174452
an immunohistochemical study of endocrine cells in the proximal duodenum of eight marsupial species.the proximal duodenum of eight marsupial species, (koala, common brushtail possum, ring-tailed possum, common wombat, great grey kangaroo, parma wallaby, short-nosed bandicoot and tiger cat) were investigated immunohistochemically using 12 specific antisera for gut hormones. several types of immunoreactive cells were seen on the intestinal villi and in crypts of these species: 9 types in the koala; 8 types in the common brushtail possum; 7 types in the common wombat; 6 types in the short-nosed b ...19902182587
seasonal breeding in two marsupials, the bandicoot isoodon macrourus and the possum trichosurus vulpecula. 19902200044
neurogenesis in a marsupial: the brush-tailed possum (trichosurus vulpecula). i. visual and auditory pathways.the times of origin of neurons in the visual and auditory systems were studied in a marsupial, the brush-tailed possum, using tritiated thymidine autoradiography. within the subcortical visual pathways, most neurons are generated between postnatal days 5 and 21, and the neurons of the primary visual cortex up to postnatal day 68. in the subcortical auditory pathways, most neurons are generated between postnatal days 5 and 28, and all auditory cortex neurons have appeared by postnatal day 46. neu ...19902245313
neurogenesis in a marsupial: the brush-tailed possum (trichosurus vulpecula). ii. sensorimotor pathways.the times of origin of neurons in sensorimotor pathways of the marsupial brush-tailed possum were determined with 3h-thymidine autoradiography. a series of 20 possums were injected with 3h-thymidine from postnatal days 5-95 and were normally allowed to survive until the brain cytoarchitecture was mature. brain stem and spinal sensorimotor regions were not labelled in our study and presumably form before birth in order to enable the newborn young to make the journey from the birth canal to the po ...19902245314
angiotensin receptors in an australian marsupial, the brushtail possum trichosurus this study, the binding properties of angiotensin receptors were examined in the liver, adrenal, brain, and vascular tissue of the brushtail possum, trichosurus vulpecula. with 125i-ile5-angiotensin ii as the radioligand, the binding affinity (ka) and receptor number (r0) were estimated for the liver (ka = 3.60 +/- 0.31 liters/nmol; r0 = 23.8 +/- 1.30 pmol/g tissue; n = 8) and adrenal (ka = 1.68 +/- 0.29 liters/nmol; r0 = 1.67 +/- 0.23 pmol/g tissue; n = 8). specific binding was not found in ...19902295416
influence of daylength on the initiation of the breeding season of the marsupial possum, trichosurus queensland, possums in the wild and in captivity first give birth during march and continue to give birth throughout the year until november. in this study the effect of short daylengths on the initiation of breeding activity was examined. one male and 4 female possums were transferred from an outside enclosure into a light control room (10 h light, 14 h dark) on 22 november. a control group of possums was housed in outside enclosures. the possums held in the light room gave birth 81.2 +/- 14 ...19902325020
estrogen receptors in the adrenal cortex of the possum (trichosurus vulpecula).1. specific [3h]estradiol binding activity with characteristics of estrogen receptors was found in the cytosols and nuclear extracts of the adrenal cortex proper and special zone of the brushtail possum (trichosurus vulpecula). 2. the specific estradiol receptor had a sedimentation coefficient on sucrose gradients of approximately 9s and a molecular weight on gel filtration of more than 200,000. the adrenal cortex cytosol binds [3h]estradiol with high affinity (ka 5.5 x 10(9) m-1), and limited c ...19902361366
vascular and avascular retinae in mammals. a funduscopic and fluorescein angiographic study.intraretinal blood vessels are present in some and absent in other vertebrate species, including the mammals. among the marsupials, both vascular and avascular retinae are seen. we determined the funduscopic appearance of the eye, investigated the functional aspects of ocular blood flow in both types of retina in marsupials and compared our results with known patterns in placental mammals. the australian polyprotodont marsupials, the tasmanian devil, sarcophilus harrisii, and the quoll, dasyurus ...19902375974
some effects of breeding season and castration on the prostate and epididymis of the brushtail possum, trichosurus an attempt to understand the mechanism(s) responsible for the reported marked seasonal increase in prostatic, but not epididymal, weight in t. vulpecula, a number of parameters were measured in tissues from mature, entire males sampled within and outside of the breeding season and from castrates. conditions for the measurement of cytosol androgen receptors were also established. the weight of both the prostate and the epididymis was significantly elevated in the breeding season but the relati ...19852418813
intestinal lactase (beta-galactosidase) and other disaccharidase activities of suckling and adult common brushtail possums, trichosurus vulpecula (marsupialia:phalangeridae).small-intestinal disaccharidase activities of eight suckling t. vulpecula, aged from 34 to 150 days, and of two adult animals were investigated. intestinal maltase, isomaltase and sucrase activities increased with age, whereas lactase activities decreased. trehalase activities were relatively high in all animals and showed no obvious age-related changes. three separate beta-galactosidase activities, one neutral and two acid, acted on lactose. the neutral beta-galactosidase activity appeared to b ...19892517666
changes in milk carbohydrates during lactation in the common brushtail possum, trichosurus vulpecula (marsupialia:phalangeridae).milk samples (186) were obtained at various stages of lactation from 27 common brushtail possums (trichosurus vulpecula). qualitative and quantitative changes in the milk carbohydrates during early and mid-lactation were similar to those previously seen in other marsupials; the principal carbohydrate was lactose early in lactation and higher oligosaccharides in mid-lactation, and the hexose concentration reached a peak during mid-lactation. however, the late-lactation milk was unusual in that th ...19892561494
changes in milk composition during lactation in the common brushtail possum, trichosurus vulpecula (marsupialia: phalangeridae).the milk constituents of trichosurus vulpecula, a folivorous marsupial, showed marked quantitative and qualitative changes during the course of lactation. the milk produced in the early stages of lactation was dilute, with about 9-13% (w/w) solids during the first 3 weeks, comprising mostly carbohydrate and protein (35-40%). at 20 weeks, about three-quarters of the way through lactation, the milk was much more concentrated, about 28% solids, with lipid the predominant fraction (30-35%), after a ...19892636424
identification of 5 beta-pregnane and 5 beta-androstane derivatives in adrenal venous and peripheral blood plasma of the female possum (trichosurus vulpecula).in the possum a marked sex difference has been found in the steroids in adrenal venous plasma. four 5 beta-pregnane and four 5 alpha (beta) androstane derivatives together with ten 4-ene-3-keto steroids were isolated from the adrenal venous plasma of the female and definitively identified by gas chromatography-mass spectrometry. the major reduced steroids were: 5 beta-pregnane-3 alpha,17 alpha-diol-20-one and 5 beta-pregnane-3 alpha,17 alpha,20 alpha-triol, at concentrations of 52 +/- 12 microgr ...19892724960
identification of 5 alpha-androstane-3 alpha,17 alpha-diol in adrenal venous plasma of female possum (trichosurus vulpecula).two hitherto unidentified c19 steroids were isolated from adrenal venous blood plasma of female possum (trichosurus vulpecula). they were 5 alpha-androstane-3 alpha,17 alpha-diol and its isomer 5 beta-androstane-3 alpha,17 alpha-diol. the compounds were isolated and identified by fractionation on paper chromatograms and hplc, followed by gas chromatography-mass spectrometry after conversion to trimethylsilyl ethers. in adrenal venous plasma the concentrations of the 5 alpha-isomer ranged from 24 ...19892724963
a cyto-architectonic description of the thalamus of the tammar wallaby, macropus eugenii.very few studies are available on the cyto-architectural features of the thalamus of metatherian mammals. most of these studies describe the thalamus of a polyprotodont metatherian, the north american opossum, didelphis virginiana. studies on diprotodont metatherians are fewer still. there are two descriptions of the thalamus of the australian possum trichosurus vulpecula. the only part of the thalamus that has been described in the wallabies is the lateral geniculate nucleus. hence, there was a ...19892765853
immunocytochemical location of oxytocin and mesotocin within the hypothalamus of two australian marsupials, the bandicoot isoodon macrourus and the brushtail possum trichosurus vulpecula.the presence of oxytocin and mesotocin in the hypothalamus of two australian marsupials, the bandicoot (isoodon macrourus) and the brushtail possum (trichosurus vulpecula), was examined by immunocytochemistry. tissue was fixed in paraformaldehyde in phosphate buffer and immunoreactive cells were detected using highly specific rabbit antioxytocin and sheep anti-mesotocin as primary antisera. immunoreactive oxytocin cells were demonstrated in the paraventricular and supraoptic nuclei of bandicoot ...19892767413
neuropeptide y-like immunoreactivity is absent from most perivascular noradrenergic axons in a marsupial, the brush-tailed possum.noradrenergic perivascular axons were demonstrated in all systemic arteries and veins of a marsupial, the brush-tailed possum (trichosurus vulpecula), by a catecholamine fluorescence procedure and with antisera directed against the catecholamine-synthesizing enzymes tyrosine hydroxylase (th) and dopamine-beta-hydroxylase (d beta h). perivascular axons with neuropeptide y-like immunoreactivity (npy-li) were not found in most systemic arteries and veins using antisera which recognize npy and other ...19862879263
induction of adrenocortical special zone in the male possum (trichosurus vulpecula).the induction of adrenocortical special zone (s.z.) by gonadotrophin administration was studied in male brush tailed possums. castrated males injected with porcine fsh (nih-fsh-p2) formed well developed s.z.s, varying in sizes from 5-20% of the gland's volume. pregnant mare serum gonadotrophin (pmsg) was ineffective. from adrenal homogenates of fsh treated possums incubated with [3h]-progesterone the major conversion products were 5 beta-reduced steroid metabolites (72%) and cortisol (4%). the c ...19872881677
immunolocalization of insulin, glucagon, pancreatic polypeptide, and somatostatin in the pancreatic islets of the possum, trichosurus vulpecula.antibodies to insulin, glucagon, pancreatic polypeptide (pp), and somatostatin were used in the immunofluorescence procedure to demonstrate localization of the four hormones in cells of the pancreatic islets of the brushtailed possum, trichosurus vulpecula. most pancreatic islets revealed some differences in the topographical distribution and cell number of each endocrine cell type. insulin immunoreactive cells were observed in most islets where they occurred as groups of cells peripherally and ...19862881838
geographic distribution of restriction types of mycobacterium bovis isolates from brush-tailed possums (trichosurus vulpecula) in new zealand.dna restriction endonuclease analysis was used for intra-specific typing of mycobacterium bovis isolates from 83 brush-tailed possums (trichosurus vulpecula) obtained between 1982 and 1984 from the three major regions in new zealand with endemic bovine tuberculosis. all the isolates were found to be genetically very similar. differentiation of the isolates into 33 restriction types was achieved by using high-resolution electrophoresis and the combined results from separate digestions with the re ...19863016075
a pmsg/gnrh method for the superovulation of the monovulatory brush-tailed possum (trichosurus vulpecula).optimal ovarian stimulation with minimal degenerative changes was achieved in brush-tailed possums 3 days after a subcutaneous injection of 10 i.u. pmsg. this treatment alone did not result in ovulation and only rarely in oocyte maturation. ovulation of 8-24 mature oocytes occurred when on the 3rd day after 10 i.u. pmsg the female received 3 intramuscular injections of 50 micrograms synthetic gonadotrophin-releasing hormone (gnrh) 90 min apart. superovulation was achieved in immature, cycling, p ...19883045309
changes in prolactin in peripheral plasma during lactation in the brushtail possum trichosurus vulpecula.a heterologous double-antibody radioimmunoassay has been validated for prolactin in plasma and pituitary preparations of t. vulpecula. serial dilutions of crude pituitary homogenates and plasmas from several marsupials and purified prolactin from the tammar, macropus eugenii, showed parallel dose response curves. in both male and female possums plasma prolactin concentrations increased in response to a single intravenous injection of thyrotrophin releasing hormone. plasma prolactin concentration ...19863098213
cortico-cortical connections of the motor cortex in the brushtailed possum (trichosurus vulpecula).cortico-cortical connections of motor cortex in the marsupial brushtailed possum were traced by making injections of horseradish peroxidase (hrp) into two parts of motor cortex: the rostral agranular part which does not overlap somatosensory cortex, and the caudal part which does. following injections in motor cortex, labelled neurons were observed on the same side of the brain within somatosensory areas 1 and 2 and in parietal cortex just caudal to s1, with most neurons in cortical layers 2-4. ...20113115935
osteogenesis in two marsupial species, the bandicoot isoodon macrourus and the possum trichosurus vulpecula.skeletal development of two marsupial species, the bandicoot, isoodon macrourus and the brushtail possum, trichosurus vulpecula, has been examined in whole mount preparations using a technique of clearing and differential staining of cartilage and bone. both marsupials possess a complete cartilaginous skeleton at birth and ossification begins in the maxilla, mandible and certain bones of the forelimb soon after birth. the general pattern of ossification in these marsupials is similar to that in ...19883248963
factors influencing prostatic 5 alpha-reductase activity in possum (trichosurus vulpecula).1. there were marked differences in prostatic wts among individual possums, but no evidence of a seasonally related change in wt could be established. it was concluded that the wt differences are mainly due to the changes in secretory activities. after castration the prostate wts fell while after administration of testosterone or oestradiol partially reversed this process. 2. seven steroid conversion products were isolated from prostatic homogenates incubated with [3h] testosterone; 5 alpha-andr ...19883356127
effect of dietary terpenes on glucuronic acid excretion and ascorbic acid turnover in the brushtail possum (trichosurus vulpecula).1. glucuronic acid was excreted in the urine of the brushtail possum, trichosurus vulpecula, in response to dietary terpenes (essential oils found in eucalyptus foliage). 2. the relationship between urinary glucuronic acid and the estimated terpene content of the diet was not equimolar, but varied from 1-17%, with levels of 5-39% found in animals maintained on terpenes or eucalypt leaves for several weeks. 3. blood levels of ascorbate and the turnover rate of ascorbate were increased in the brus ...19883356132
the ultrastructure of the pituitary and the adrenal gland of three newborn marsupials (dasyurus hallucatus, trichosurus vulpecula and isoodon macrourus).the ultrastructure of the pituitary glands of the newborn northern native cat, brushtail possum and the northern brown bandicoot and the adrenal glands of the former two marsupials were examined to determine whether these endocrine glands were functional at birth. the anterior pituitary of all three species was well vascularised and many cells contained electron-dense, membrane bound granules. the adrenal glands were composed of two distinct cell populations. one group of cells possessed dark st ...19883364743
ultrastructural identification of merkel cells around the mouth of the newborn marsupial.the ultrastructure of the epidermal cells surrounding the mouth of three newborn marsupial species, the northern native cat dasyurus hallucatus, the brush tail possum trichosurus vulpecula and the northern brown bandicoot isoodon macrourus were examined. the presence of merkel cells, highly sensitive touch receptors, would suggest that the sense of touch aids the relatively underdeveloped newborn marsupial to move from the urinogenital sinus to the pouch and to locate the teat.19883364744
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