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Possums
Kinds of Possums Selected AbstractsPOSSUM scoring for laparoscopic cholecystectomy in the elderlyANZ JOURNAL OF SURGERY, Issue 7 2005Andrew L. Tambyraja Background: Physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM) scoring is a validated scoring system in the audit of surgical outcomes; however, evaluation of this system has mostly been applied to open surgical techniques. The present study examines the validity of POSSUM in predicting morbidity and mortality in patients undergoing laparoscopic cholecystectomy (LC) with the recognized risk factor for postoperative mortality of advanced age. Methods: All patients aged 80 years or over undergoing LC in one surgical unit between January 1993 and December 1999 were identified from the surgical operations database of the hospital. Case-note review was used to collate data in terms of clinical and operative factors as described in POSSUM. Observed/POSSUM estimated (O/E) ratio of morbidity and 30-day mortality were calculated. Results: Laparoscopic cholecystectomy was performed in 76 patients aged 80 years or over during the study period. Of these patients, case notes for 70 patients (92%) were available for review. Median (range) age was 83 years (80,93 years) and median (range) American Society of Anesthesiologists score was 2 (2,4). Twenty-six (34%) of 70 patients underwent cholecystectomy during an acute admission. The mean physiology severity score was 23 and operative severity score, 8. A significant postoperative morbidity was observed in 15 (22%) of 70 patients. There was no 30-day mortality. Using exponential analysis, POSSUM predicted morbidity in 15 patients and mortality in seven patients. Thus, O/E ratios for morbidity and mortality were 1 and 0, respectively. Conclusion: POSSUM scoring performs well in predicting morbidity, but overpredicts mortality, after LC in patients aged over 80 years. An assessment of its application to other laparoscopic procedures merits evaluation. [source] Elderly POSSUM, a dedicated score for prediction of mortality and morbidity after major colorectal surgery in older patientsBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 3 2010P. Tran Ba Loc Background: Several scores have been developed to evaluate surgical unit mortality and morbidity. The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) and derivatives use preoperative and intraoperative factors, whereas the Surgical Risk Scale (SRS) and Association Française de Chirurgie (AFC) score use four simple factors. To allow for advanced age in patients undergoing colorectal surgery, a dedicated score,the Elderly (E) POSSUM,has been developed and its accuracy compared with these scores. Methods: From 2002 to 2004, 1186 elderly patients, at least 65 years old, undergoing major colorectal surgery in France were enrolled. Accuracy was assessed by calculating the area under the receiver operating characteristic curve (AUC) (discrimination) and calibration. Results: The mortality and morbidity rates were 9 and 41 per cent respectively. The E-POSSUM had both a good discrimination (AUC = 0·86) and good calibration (P = 0·178) in predicting mortality and a reasonable discrimination (AUC = 0·77) and good calibration (P = 0·166) in predicting morbidity. The E-POSSUM was significantly better at predicting mortality and morbidity than the AFC score (Pc = 0·014 and Pc < 0·001 respectively). Conclusion: The E-POSSUM is a good tool for predicting mortality, and the only efficient scoring system for predicting morbidity after major colorectal surgery in the elderly. Copyright © 2010 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Evaluation of various POSSUM models for predicting mortality in patients undergoing elective oesophagectomy for carcinomaBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 9 2007F. Lai Background: The aim of the study was to validate the use of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM), Portsmouth (P) POSSUM and upper gastrointestinal (O) POSSUM models in patients undergoing elective thoracic oesophagectomy for carcinoma. Methods: The observed in-hospital mortality rates in 545 patients undergoing elective thoracic oesophagectomy for squamous cell carcinoma of the oesophagus in all public hospitals in Hong Kong was compared with rates predicted by POSSUM, P-POSSUM and O-POSSUM. The discriminatory power of these models was assessed using receiver,operator characteristic (ROC) curve analysis. Results: The observed mortality rate was 5·5 per cent, whereas rates predicted by POSSUM, P-POSSUM and O-POSSUM were 15·0, 4·7 and 10·9 per cent respectively. P-POSSUM showed no lack of fit (P = 0·814), but POSSUM (P < 0·001) and O-POSSUM (P = 0·002) showed lack of fit against observed mortality. POSSUM overpredicted mortality across nearly all risk groups, whereas O-POSSUM overpredicted mortality in patients with low physiological scores and in older patients. POSSUM (area under ROC curve 0·776) and P-POSSUM (0·776) showed equally good discriminatory power but O-POSSUM (0·676) was inferior. Conclusion: P-POSSUM provided the most accurate prediction of in-hospital mortality in this group of patients who had elective oesophagectomy. Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Predicting postoperative morbidity by clinical assessmentBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 1 2005P. M. Markus Background: The aim of this study was to determine the accuracy of prediction of the surgeon's ,gut-feeling' in estimating postoperative outcome. Methods: A prospective series of 1077 consecutive patients undergoing major hepatobiliary or gastrointestinal surgery were studied. Patients having elective (n = 827) and emergency (n = 250) procedures were included. The surgeon predicted the development of postoperative complications immediately after completion of surgery on a scale from 0 to 100 per cent. These predictions were compared with the actual outcome and with predictions made using the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM). The Portsmouth predictor equation (P-POSSUM) was applied for the estimation of mortality. Results: The observed morbidity and mortality rates were 29·5 and 3·4 per cent respectively. POSSUM predicted a morbidity rate of 46·4 per cent and P-POSSUM a mortality rate of 6·9 per cent. The surgeon's gut-feeling was more accurate in the prediction of morbidity at 32·1 per cent. On the basis of gut-feeling, surgeons overpredicted morbidity in elective surgery, but underestimated the risk of complications in the emergency setting. The (P)-POSSUM scoring system overpredicted morbidity and mortality for elective and emergency operations. Conclusion: The surgeon's gut-feeling is a good predictor of postoperative outcome, especially after elective surgery. (P)-POSSUM overpredicted morbidity and mortality in this series of major gastrointestinal and hepatobiliary operations. Copyright © 2005 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Development of a dedicated risk-adjustment scoring system for colorectal surgery (colorectal POSSUM),,BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 9 2004P. P. Tekkis Background: The aim of the study was to develop a dedicated colorectal Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (CR-POSSUM) equation for predicting operative mortality, and to compare its performance with the Portsmouth (P)-POSSUM model. Methods: Data were collected prospectively from 6883 patients undergoing colorectal surgery in 15 UK hospitals between 1993 and 2001. After excluding missing data and 93 patients who did not satisfy the inclusion criteria, 4632 patients (68·2 per cent) underwent elective surgery and 2107 had an emergency operation (31·0 per cent); 2437 operations (35·9 per cent) for malignant and 4267 (62·8 per cent) for non-malignant diseases were scored. Stepwise logistic regression analysis was used to develop an age-adjusted POSSUM model and a dedicated CR-POSSUM model. A 60 : 40 per cent split-sample validation technique was adopted for model development and testing. Observed and expected mortality rates were compared. Results: The operative mortality rate for the series was 5·7 per cent (387 of 6790 patients) (elective operations 2·8 per cent; emergency surgery 12·0 per cent). The CR-POSSUM, age-adjusted POSSUM and P-POSSUM models had similar areas under the receiver,operator characteristic curves. Model calibration was similar for CR-POSSUM and age-adjusted POSSUM models, and superior to that for the P-POSSUM model. The CR-POSSUM model offered the best overall accuracy, with an observed : expected ratio of 1·000, 0·998 and 0·911 respectively (test population). Conclusion: The CR-POSSUM model provided an accurate predictor of operative mortality. External validation is required in hospitals different from those in which the model was developed. Copyright © 2004 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Evaluation of POSSUM and P-POSSUM scoring systems in assessing outcome after laparoscopic colectomy (Br J Surg 2003; 90: 1280,1284)BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 12 2003K. Slim No abstract is available for this article. [source] The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) (Br J Surg 2003; 90: 157,165)BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 5 2003A. L. Tambyraja No abstract is available for this article. [source] Delayed stoma formation in Fournier's gangreneCOLORECTAL DISEASE, Issue 6 2004C. S. Bronder Abstract Fournier's gangrene is traditionally treated with prompt surgical debridement and in many cases a diverting colostomy is also fashioned during the same procedure. We present four cases where stoma formation was delayed until the second look procedure. The physiological states at the time of either procedure were compared using POSSUM. The results showed an improvement in the physiological condition in all patients at the time of the second operation, suggesting that a delay can potentially improve prognosis in such cases. [source] Diet selection in the green ringtail possum (Pseudochirops archeri): A specialist folivore in a diverse forestAUSTRAL ECOLOGY, Issue 7 2006KATHERINE M. W. JONES Abstract This study investigated the feeding ecology of the green ringtail possum, Pseudochirops archeri (Pseudocheiridae) in a tropical rainforest with 94 plant species in the canopy. Over 50% of tree use was from only four tree species, Aleurites rockinghamensis, Ficus fraseri, Arytera divaricata and Ficus copiosa. These species were used significantly more frequently than would be expected if tree species were selected randomly in proportion to their relative abundance in the forest. Conversely, 88 other tree species present were used less frequently than expected. Possums also favoured particular individual trees within some of the preferred tree species. In 91% of feeding observations, possums consumed mature leaves only. The availability of young leaves, flowers and fruit varied throughout the year, with a peak in availability of these resources during the early wet season. By primarily selecting mature leaves, green ringtail possums reduce their dependence on seasonally variable resources. We suggest that green ringtail possums should be considered as specialist folivores, focusing on only a few of the tree species available, possibly due to advantages associated with limiting the number of plant secondary metabolites in their diet. Furthermore, they favour certain individual trees within species, perhaps due to intraspecific variation in plant secondary metabolites or nutrient content, behaviour that has been well established in eucalypt folivores. We conclude that green ringtail possums are highly specialized in their feeding ecology, limiting their diet to a small number of continuously available food items. [source] Correlative and mechanistic models of species distribution provide congruent forecasts under climate changeCONSERVATION LETTERS, Issue 3 2010Michael R. Kearney Abstract Good forecasts of climate change impacts on extinction risks are critical for effective conservation management responses. Species distribution models (SDMs) are central to extinction risk analyses. The reliability of predictions of SDMs has been questioned because models often lack a mechanistic underpinning and rely on assumptions that are untenable under climate change. We show how integrating predictions from fundamentally different modeling strategies produces robust forecasts of climate change impacts on habitat and population parameters. We illustrate the principle by applying mechanistic (Niche Mapper) and correlative (Maxent, Bioclim) SDMs to predict current and future distributions and fertility of an Australian gliding possum. The two approaches make congruent, accurate predictions of current distribution and similar, dire predictions about the impact of a warming scenario, supporting previous correlative-only predictions for similar species. We argue that convergent lines of independent evidence provide a robust basis for predicting and managing extinctions risks under climate change. [source] Ultrastructural characteristics of the process of cornification in developing claws of the brushtail possum (Trichosurus vulpecula)ACTA ZOOLOGICA, Issue 3 2009Lorenzo Alibardi Abstract Cornification of developing claws in the brush possum has been analysed by electron microscopy and compared with the process in other tetrapods. Newborns from 3 to 60 days postparturition were studied. After formation of symmetric and round outgrowth in digits the epidermis becomes thicker in the dorsal with respect to the ventral digit tip. The claw elongates forming the unguis and a shorter subunguis. Spinosus keratinocytes in both unguis and subunguis accumulate tonofilaments that fill their cytoplasm. Keratohyaline-like granules are formed in early stages of differentiation in both unguis and subunguis but they later disappear in highly cornified corneocytes. Tonofilaments become electron-dense in keratinocytes of the precorneous layer in the large corneocytes of the unguis and in narrow corneocytes of the subunguis. Keratin bundles transform into an amorphous corneous material that embeds or masks the original keratin intermediate filaments. Nucleated corneocytes are accumulated in the unguis while thinner corneocytes are present in the subunguis. The latter contain a dense material, possibly containing high sulphur keratin associated proteins, as occurs during cornifcation of the cortex and cuticle hair cells and in the nail. The process of cornification of mammalian claws is compared with that of reptilian and avian claws. [source] Electrical activation of common bile duct nerves modulates sphincter of Oddi motility in the Australian possumHPB, Issue 4 2005Y. Sonoda Abstract Background: Sphincter of Oddi (SO) motility is regulated by extrinsic and intrinsic nerves. The existence of neural circuits between the SO and the proximal extrahepatic biliary tree has been reported, but they are poorly understood. Using electrical field stimulation (EFS), we determined if a neural circuit exists between the common bile duct (CBD) and the SO in anaesthetized Australian brush-tailed possums. Methods: The gallbladder, cystic duct or CBD were subjected to EFS with a stimulating electrode. Spontaneous SO phasic waves were measured by manometry. Results: EFS at sites on the distal CBD (12,20 mm proximal to the SO), but less commonly at more proximal CBD, evoked a variety of responses consisting of an excitatory and/or inhibitory phase. Bi-phasic responses consisting of an excitation followed by inhibition were the most common. Tri-phasic responses were also observed as well as excitation or inhibition only. These evoked responses were blocked by topical application of local anaesthetic to the distal CBD or transection of the CBD. EFS at sites on the gallbladder body, neck or cystic duct did not consistently evoke an SO response. Pretreatment with atropine or guanethidine reduced the magnitude of the evoked response by about 50% (p<0.05), pretreatment with hexamethonium had no consistent effect and pretreatment with a nitric oxide synthase inhibitor increased the response. Discussion: A neural circuit(s) between the SO and the distal CBD modulates SO motility. Damage to this area of the CBD during bile duct exploration surgery could adversely affect SO motility. [source] cDNA cloning of the polymeric immunoglobulin receptor of the marsupial Macropus eugenii (tammar wallaby)INTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2002C. L. Taylor Summary cDNA encoding a marsupial polymeric immunoglobulin receptor (pIgR) was isolated from Macropus eugenii (tammar wallaby) mammary lymph node primarily by reverse transcriptase coupled polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) PCR. This resulted in a 5, truncated clone and, in order to obtain the full-length sequence, genomic walking PCR was utilized. The complete sequence consists of 2696 bp of cDNA and encodes a predicted polypeptide of 732 amino acids. The wallaby sequence is highly conserved in relation to the only other reported marsupial pIgR sequence, that of Trichosurus vulpecula (brushtail possum), having a nucleotide identity of 86.7% and a deduced amino acid identity of 79.9%. The wallaby nucleotide sequence also has a moderate degree of similarity with the pIgR sequences of eutherian mammals, being most similar to that of the rat, with an identity of 63.1%. At the amino acid level, in comparison to eutherian sequences, the wallaby pIgR is most similar to that of humans with an identity of 52.6%. pIgR phylogenetic trees were constructed for tammar wallaby, brushtail possum and several eutherian mammal cDNA and deduced amino acid sequences. In both DNA and protein analyses, the eutherian sequences formed a sister clade to the exclusion of the marsupial sequences, in agreement with the current view of mammalian evolution. [source] Molecular cloning of four lambda light chain cDNAs from the Australian brushtail possum Trichosurus vulpeculaINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2002K. Belov Summary A brushtail possum mesenteric lymph node cDNA library was screened with a grey short-tail opossum C, probe and four immunoglobulin lambda cDNAs were isolated. Two of the isolated clones (L5 and L10) contained identical framework 4 regions and constant regions (but different variable regions), suggesting that the possum lambda locus is organized as multiple J-C pairs , a feature seen in the opossum and placental mammals. The cloning of the lambda light chain cDNAs signifies the completion of the basic molecular characterization of the brushtail possum immunoglobulin repertoire. The availability of this sequence data will allow extensive analysis of the immune response of the brushtail possum at the molecular level, as well as the development of specific immunological reagents for detection of immunoglobulin molecules at the protein level. [source] BRIEF COMMUNICATION: Histology of the pouch epithelium and the mammary glands during chemically induced oestrus in the brushtail possum (Trichosurus vulpecula)JOURNAL OF ANATOMY, Issue 1 2005Julie M. Old Abstract Changes in the epithelium of the maternal pouch and the mammary gland of brushtail possums (Trichosurus vulpecula) were examined after animals were treated to induce ovulation with follicle-stimulating hormone (FSH), luteinizing hormone (LH), pregnant mares' serum gonadotrophin (PMSG) and oestradiol. The mammary glands were similar in appearance to those described in eutherian mammals and in previous studies on other marsupials. Exposure of possums to these compounds, particularly PSMG, appeared to result in changes in the mammary glands that could be associated with milk/secretion production. In contrast, the pouch epithelium had a similar histological appearance to that of epithelium from other parts of the body regardless of whether the animal was exposed to stimulants. These preliminary observations are discussed in the context of the purported role of the pouch epithelium and the mammary gland in production of secretions at oestrus and provision of immunological protection to the neonatal marsupial. [source] Blowfly succession from possum (Trichosurus vulpecula) carrion in a sheep-farming zoneMEDICAL AND VETERINARY ENTOMOLOGY, Issue 4 2006M. D. LANG Abstract The significance of brushtail possum, Trichosurus vulpecula Kerr (Diprotodontia: Phalangeridae) carcasses to the succession and production of Diptera species and its relevance to fly strike management in Tasmania, Australia was examined. Calliphora stygia (Fabricius), Lucilia sericata (Meigen) and Calliphora vicina Robineau,Desvoidy (Diptera: Calliphoridae) were found to be the most abundant and Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae) always the least abundant (< 1%) of the putative primary fly invading species to emerge. Carcasses that were left for up to 15 days in the field before being exposed to flies for 2 days also acted as breeding sites for large numbers of all primary fly species, with the exception of L. cuprina. Ordination analysis revealed no relationship between possum carcasses according to their length of exposure but did show significant negative associations between the number of putative secondary invaders (Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae), Chrysomya varipes (Macquart) (Diptera: Calliphoridae) and putative tertiary flies (Hydrotaea rostrata Robineau,Desvoidy (Diptera: Muscidae)) to the number of C. vicina or C. stygia to emerge. There was enormous variability in the numbers of secondary/tertiary fly species to emerge from carcasses (0,11 450) that negatively correlated with the proportion of all flies to emerge that were primary, and with the mean size of adult L. sericata. Although carcass temperatures, especially those with a large larval population, were elevated, this did not appear to result in significant pre-adult fly mortality. The most important primary fly strike species L. cuprina was only found in insignificant numbers, whereas three other members of the fly strike fauna C. stygia, L. sericata and Ch. rufifacies did use possum carrion as an important breeding resource, but left implications for fly strike management inconclusive. [source] Towards a ZP-based contraceptive for marsupials: Comparative analysis and developmental expression of marsupial ZP genesMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 12 2007Carmen A. McCartney Abstract Fertility control in the form of a zona pellucida (ZP)-based immunocontraceptive has shown potential as a humane form of control for overabundant marsupials including the brushtail possum and macropods. Further refinement and development of a ZP-based vaccine requires detailed knowledge of the protein structure and expression in order to ensure maximum efficacy and specificity. Sequencing and comparative analysis of the ZP3 protein from three marsupial orders in this study found a high overall level of conservation; within order Diprotodontia, the ZP3 protein is 86.9,98.9% identical. ZP3 identity falls to 56.6,57.2%, when the grey, short-tailed opossum (a Didelphimorphian) is compared to dasyurid and diprotodontan marsupials. This is similar to its amino acid identity with ZP3 from eutherian species (50.7,52.8%). Comparison of a 21 amino acid epitope in marsupial ZP3 that has shown contraceptive effects, reveals 95,100% identity between the four macropodid species, 81,86% amino acid identity between brushtail possum and the macropods and 67,71% identity between the diprotodontans and the fat-tailed dunnart (a dasyurid). This is comparable to the level of identity between related eutherian mammals. The expression pattern of three ZP genes during brushtail possum and tammar wallaby pouch young development was examined by RT-PCR. This analysis of ZP gene expression has confirmed that ZP mRNA transcription begins in the ovary during pouch young development by about 51 days of age. The presence of ZP transcripts at this stage in pouch young development suggests that marsupial ZP gene transcription begins before the onset of follicular development. Mol. Reprod. Dev. 74: 1581,1589, 2007. © 2007 Wiley-Liss, Inc. [source] Predicting the unexpected: using a qualitative model of a New Zealand dryland ecosystem to anticipate pest management outcomesAUSTRAL ECOLOGY, Issue 4 2009DAVID S. L. RAMSEY Abstract Pest management is expensive and there is often uncertainty about the benefits for the resources being protected. There can also be unintended consequences for other parts of the ecosystem, especially in complex food webs. In making decisions managers generally have to rely on qualitative information collected in a piecemeal fashion. A method to assist decision making is a qualitative modelling approach using fuzzy cognitive maps, a directed graphical model related to neural networks that can take account of interactions between pests and conservation assets in complex food webs. Using all available information on relationships between native and exotic resources and consumers, we generated hypotheses about potential consequences of single-species and multi-species pest control on the long-term equilibrium abundances of other biotic components of an ecosystem. We applied the model to a dryland ecosystem in New Zealand because we had good information on its trophic structure, but the information on the strength of species interactions was imprecise. Our model suggested that pest control is unlikely to significantly boost native invertebrates and lizards in this ecosystem, suggesting that other forms of management may be required for these groups. Most of the pest control regimes tested resulted in greater abundances of at least one other pest species, which could potentially lead to other management problems. Some of the predictions were unexpected, such as more birds resulting from possum and mouse control. We also modelled the effects of an increase in invasive rabbits, which led to unexpected declines of stoats, weasels, mice and possums. These unexpected outcomes resulted from complex indirect pathways in the food web. Fuzzy cognitive maps allow rapid construction of prototype models of complex food webs using a wide range of data and expert opinion. Their utility lies in providing direction for future monitoring efforts and generating hypotheses that can be tested with field experiments. [source] Diet selection in the green ringtail possum (Pseudochirops archeri): A specialist folivore in a diverse forestAUSTRAL ECOLOGY, Issue 7 2006KATHERINE M. W. JONES Abstract This study investigated the feeding ecology of the green ringtail possum, Pseudochirops archeri (Pseudocheiridae) in a tropical rainforest with 94 plant species in the canopy. Over 50% of tree use was from only four tree species, Aleurites rockinghamensis, Ficus fraseri, Arytera divaricata and Ficus copiosa. These species were used significantly more frequently than would be expected if tree species were selected randomly in proportion to their relative abundance in the forest. Conversely, 88 other tree species present were used less frequently than expected. Possums also favoured particular individual trees within some of the preferred tree species. In 91% of feeding observations, possums consumed mature leaves only. The availability of young leaves, flowers and fruit varied throughout the year, with a peak in availability of these resources during the early wet season. By primarily selecting mature leaves, green ringtail possums reduce their dependence on seasonally variable resources. We suggest that green ringtail possums should be considered as specialist folivores, focusing on only a few of the tree species available, possibly due to advantages associated with limiting the number of plant secondary metabolites in their diet. Furthermore, they favour certain individual trees within species, perhaps due to intraspecific variation in plant secondary metabolites or nutrient content, behaviour that has been well established in eucalypt folivores. We conclude that green ringtail possums are highly specialized in their feeding ecology, limiting their diet to a small number of continuously available food items. [source] Phylogenetic analysis of Porphyromonas species isolated from the oral cavity of Australian marsupialsENVIRONMENTAL MICROBIOLOGY, Issue 9 2008Deirdre Mikkelsen Summary Porphyromonas species are frequently isolated from the oral cavity and are associated with periodontal disease in both animals and humans. Black, pigmented Porphyromonas spp. isolated from the gingival margins of selected wild and captive Australian marsupials with varying degrees of periodontal disease (brushtail possums, koalas and macropods) were compared phylogenetically to Porphyromonas strains from non-marsupials (bear, wolf, coyote, cats and dogs) and Porphyromonas gingivalis strains from humans using 16S rRNA gene sequence analysis. The results of the phylogenetic analysis identified three distinct groups of strains. A monophyletic P. gingivalis group (Group 1) contained only strains isolated from humans and a Porphyromonas gulae group (Group 2) was divided into three distinct subclades, each containing both marsupial and non-marsupial strains. Group 3, which contained only marsupial strains, including all six strains isolated from captive koalas, was genetically distinct from P. gulae and may constitute a new Porphyromonas species. [source] Electrical activation of common bile duct nerves modulates sphincter of Oddi motility in the Australian possumHPB, Issue 4 2005Y. Sonoda Abstract Background: Sphincter of Oddi (SO) motility is regulated by extrinsic and intrinsic nerves. The existence of neural circuits between the SO and the proximal extrahepatic biliary tree has been reported, but they are poorly understood. Using electrical field stimulation (EFS), we determined if a neural circuit exists between the common bile duct (CBD) and the SO in anaesthetized Australian brush-tailed possums. Methods: The gallbladder, cystic duct or CBD were subjected to EFS with a stimulating electrode. Spontaneous SO phasic waves were measured by manometry. Results: EFS at sites on the distal CBD (12,20 mm proximal to the SO), but less commonly at more proximal CBD, evoked a variety of responses consisting of an excitatory and/or inhibitory phase. Bi-phasic responses consisting of an excitation followed by inhibition were the most common. Tri-phasic responses were also observed as well as excitation or inhibition only. These evoked responses were blocked by topical application of local anaesthetic to the distal CBD or transection of the CBD. EFS at sites on the gallbladder body, neck or cystic duct did not consistently evoke an SO response. Pretreatment with atropine or guanethidine reduced the magnitude of the evoked response by about 50% (p<0.05), pretreatment with hexamethonium had no consistent effect and pretreatment with a nitric oxide synthase inhibitor increased the response. Discussion: A neural circuit(s) between the SO and the distal CBD modulates SO motility. Damage to this area of the CBD during bile duct exploration surgery could adversely affect SO motility. [source] Husbandry and breeding of the Striped possum Dactylopsila trivirgata at London ZSLINTERNATIONAL ZOO YEARBOOK, Issue 1 2005A. McKENNA Detailed information on either wild or captive Striped possums Dactylopsila trivirgata (Gray, 1858) is sparse. In 1996 a number of specimens became available to the European Monotreme and Marsupial Taxon Advisory Group (TAG), which recommended that the animals should be distributed to three zoos (London ZSL, Poznan Zoo and Berlin Zoologischer Garten) so that a management and breeding protocol could be developed in case this fairly common species becomes threatened in the future. London ZSL acquired 3.3 Striped possums to establish a founder captive population and two joeys were born, one in April 1999 and the other in March 2000. This article charts the husbandry protocols, breeding behaviour and infant development for Striped possums in captivity. [source] BRIEF COMMUNICATION: Histology of the pouch epithelium and the mammary glands during chemically induced oestrus in the brushtail possum (Trichosurus vulpecula)JOURNAL OF ANATOMY, Issue 1 2005Julie M. Old Abstract Changes in the epithelium of the maternal pouch and the mammary gland of brushtail possums (Trichosurus vulpecula) were examined after animals were treated to induce ovulation with follicle-stimulating hormone (FSH), luteinizing hormone (LH), pregnant mares' serum gonadotrophin (PMSG) and oestradiol. The mammary glands were similar in appearance to those described in eutherian mammals and in previous studies on other marsupials. Exposure of possums to these compounds, particularly PSMG, appeared to result in changes in the mammary glands that could be associated with milk/secretion production. In contrast, the pouch epithelium had a similar histological appearance to that of epithelium from other parts of the body regardless of whether the animal was exposed to stimulants. These preliminary observations are discussed in the context of the purported role of the pouch epithelium and the mammary gland in production of secretions at oestrus and provision of immunological protection to the neonatal marsupial. [source] Predicting the effects of perturbations on ecological communities: what can qualitative models offer?JOURNAL OF ANIMAL ECOLOGY, Issue 5 2005DAVE RAMSEY Summary 1Quantitative predictions of the effects of perturbations on communities of interacting species have often proved to be difficult. However, if precise predictions are not a requirement then qualitative models of community dynamics offer an alternative method for predicting species responses to perturbations. 2We used two qualitative modelling approaches to predict the effects of predator control on the fledging rate of an endangered New Zealand bird, the North Island kokako. The first approach was based on loop analysis and provided predictions on the probable direction of change in species abundances to single species perturbations. The second approach, ,fuzzy interaction webs', used fuzzy logic in the framework of a fuzzy cognitive map to provide predictions on the probable magnitude of change in species abundances to perturbations. 3Using both methods, we predicted the qualitative change in the equilibrium fledging rates of kokako under various regimes of single- and multispecies predator control (ship rats, brushtail possums and stoats). Single species control was insufficient to lift the fledging rate from ,low' to ,moderate'. However, simultaneous control of both ship rats and possums had the greatest influence on the fledging rates compared with any other combination as a result of the additional indirect effect of ship rat control on stoat abundance. 4We propose qualitative modelling of community dynamics as a method suitable for predicting the effects of perturbations in complex ecological communities that can encapsulate diverse sources of knowledge about food web interactions. We believe that these methods are a useful set of heuristic tools that can be used to propose testable hypotheses about ecosystem functioning that can complement existing statistical and quantitative modelling approaches. [source] The effects of reducing population density on contact rates between brushtail possums: implications for transmission of bovine tuberculosisJOURNAL OF APPLIED ECOLOGY, Issue 5 2002Dave Ramsey Summary 1Interactions during mating are thought to be an important mechanism for transmission of tuberculosis (Tb) Mycobacterium bovis in the brushtail possum Trichosurus vulpecula . However, little information is available on the frequency of contacts between males and females in oestrus during the breeding season, and the relationship between mating contacts and population density. 2We used radio-telemetry to record contacts between male and oestrous and non-oestrous female possums, and determined paternity of offspring using DNA analysis. This was repeated following the removal of c . 70% of the resident possums to determine the effect of reducing density on the contact rate. 3We could not detect any significant differences in the contact rate between oestrous and non-oestrous females and males, either before or after the density reduction, even when paternity was positively identified from DNA analysis. This suggests that actual mating contacts could not be distinguished from other agonistic or affiliative contact behaviours. 4Despite this, the relationships between male,female and male,male contact rates and population density were non-linear convex-up, implying that the contact rate during the breeding season did not decrease in proportion to reductions in density. This appeared to be driven by the enlargement of male ranges and a corresponding increase in male overlap of female ranges following the density reduction. 5The form of the contact rate function will influence predictions of disease spread in epidemiological models for Tb in wildlife. This has major implications for the development of tactical approaches to disease management based on such models. [source] Glide angle in the genus Petaurus and a review of gliding in mammalsMAMMAL REVIEW, Issue 1 2000Stephen M. Jackson ABSTRACT The gliding angle of the Mahogany Glider Petaurus gracilis and the Sugar Glider Petaurus breviceps was determined from field studies by measuring the height of launch and landing of glides and the distance travelled. This showed no significant difference between these two species in glide ratio, which averaged 1.91 and 1.82 m distance per 1 m loss in altitude, respectively, nor in glide angle which averaged 28.26° and 29.69° for the Mahogany Glider and Sugar Glider, respectively. Significant differences were found between them for height of launch (19.75 and 11.96 m, respectively), height of landing (4.48 and 1.95 m, respectively), diameter at breast height of landing tree (44.12 and 23.22 cm, respectively), and glide distance (29.71 and 20.42 m, respectively). An examination of the ratio of interorbital width to maximum skull width of gliding and nongliding possums was measured from museum skulls to examine whether gliders have eyes wider apart, to allow triangulation of distance in preparation for gliding. Gliding possums showed a trend toward having a larger interorbital width than nongliding possums, although there appear to be several factors acting on the interorbital width. Museum study skins of all gliding marsupials were measured to determine the relationship between patagium surface area and body mass which showed a clear relationship (r2 = 0.9688). A comparison of gliding behaviour, patagium, development of limbs, tail morphology and mass was also made between gliding marsupials and other gliding mammals. [source] Secretin induces variable inhibition of motility in different parts of the Australian possum sphincter of OddiNEUROGASTROENTEROLOGY & MOTILITY, Issue 5 2001B. O. Al-Jiffry The sphincter of Oddi (SO) may not function as a single structure. We aimed to determine the response of the proximal and distal segments of the bile duct (BD-SO) and pancreatic duct (PD-SO) components of the SO to secretin, with and without neural blockade with tetrodotoxin (TTX). In anaesthetized Australian possums, separate manometry catheters were placed in the proximal and distal BD-SO or PD-SO segments to record motility. Secretin, 50,1000 ng kg,1, was administered, followed by TTX, and re-administration of secretin, 500 and 1000 ng kg,1. Changes in the motility index (MI, frequency × mean amplitude) were determined. Statistical analysis utilized repeated-measures ANOVA. Secretin produced a dose-dependent decrease in MI from the proximal and distal BD-SO and PD-SO (all P < 0.001). The maximum inhibition, at 1000 ng kg,1, was 21 ± 4%, 33 ± 6% and 42 ± 5% of control (mean ± SEM), for proximal and distal BD-SO, and distal PD-SO, respectively. The proximal PD-SO MI, however, was inhibited to 62 ± 6% of control, at 1000 ng kg,1. TTX enhanced the secretin-induced response to the same level at the four sites (P < 0.02). We conclude that secretin inhibits the motility of the possum SO in a nonuniform manner and is modulated by neural activity. [source] Early ontogenetic trajectories vary among defence chemicals in seedlings of a fast-growing eucalyptAUSTRAL ECOLOGY, Issue 2 2010CLARE MCARTHUR Abstract Ontogenetic changes in leaf chemistry can affect plant,herbivore interactions profoundly. Various theoretical models predict different ontogenetic trajectories of defence chemicals. Empirical tests do not consistently support one model. In Eucalyptus nitens, a fast-growing tree, we assessed early developmental changes to seedlings, in foliage concentrations of nitrogen and the full suite of known secondary (defence) chemicals. This included the terpene, ,-pinene, whose impact on marsupial herbivory is unknown. To test for the influence of abiotic conditions on the ontogenetic trajectories we overlaid a nutrient treatment. Ontogenetic trajectories varied among compounds. Sideroxylonals and cineole were barely detected in very young seedlings, but increased substantially over the first 200 days. Total phenolic concentration increased fourfold over this time. In contrast, ,-pinene concentration peaked within the first 60 days and again between 150 and 200 days. Nutrients altered the degree but not the direction of change of most chemicals. A shorter trial run at a different season showed qualitatively similar patterns, although ,-pinene concentration started very high. We investigated the effect of detected levels of ,-pinene and cineole on food intake by two mammalian herbivores, common brushtail possums (Trichosurus vulpecula) and red-bellied pademelons (Thylogale billardierii). Under no-choice conditions neither terpene reduced intake; but with a choice, possums preferred ,-pinene to cineole. The ontogenetic trajectories of most compounds were therefore consistent with models that predict an increase as plants develop. Published data from later developmental stages in E. nitens also confirm this pattern. ,-Pinene, however, was the only secondary compound found at significant levels in very young seedlings; but it did not constrain feeding by marsupial herbivores. Models must allow for different roles of defensive secondary chemicals, presumably associated with different selective pressures as plants age, which result in different ontogenetic trajectories. [source] Predicting the unexpected: using a qualitative model of a New Zealand dryland ecosystem to anticipate pest management outcomesAUSTRAL ECOLOGY, Issue 4 2009DAVID S. L. RAMSEY Abstract Pest management is expensive and there is often uncertainty about the benefits for the resources being protected. There can also be unintended consequences for other parts of the ecosystem, especially in complex food webs. In making decisions managers generally have to rely on qualitative information collected in a piecemeal fashion. A method to assist decision making is a qualitative modelling approach using fuzzy cognitive maps, a directed graphical model related to neural networks that can take account of interactions between pests and conservation assets in complex food webs. Using all available information on relationships between native and exotic resources and consumers, we generated hypotheses about potential consequences of single-species and multi-species pest control on the long-term equilibrium abundances of other biotic components of an ecosystem. We applied the model to a dryland ecosystem in New Zealand because we had good information on its trophic structure, but the information on the strength of species interactions was imprecise. Our model suggested that pest control is unlikely to significantly boost native invertebrates and lizards in this ecosystem, suggesting that other forms of management may be required for these groups. Most of the pest control regimes tested resulted in greater abundances of at least one other pest species, which could potentially lead to other management problems. Some of the predictions were unexpected, such as more birds resulting from possum and mouse control. We also modelled the effects of an increase in invasive rabbits, which led to unexpected declines of stoats, weasels, mice and possums. These unexpected outcomes resulted from complex indirect pathways in the food web. Fuzzy cognitive maps allow rapid construction of prototype models of complex food webs using a wide range of data and expert opinion. Their utility lies in providing direction for future monitoring efforts and generating hypotheses that can be tested with field experiments. [source] Resilience of arboreal folivores to habitat damage by a severe tropical cycloneAUSTRAL ECOLOGY, Issue 4 2008ROBYN F. WILSON Abstract Severe tropical cyclones greatly modify habitat of arboreal folivores by destroying forest canopy, reducing structure and complexity and defoliating remaining trees. We hypothesized that forest modification following severe Cyclone Larry would stress arboreal folivores of the Family Pseudocheiridae and be reflected in increased home ranges and a decrease in body condition. We conducted 19 pre-cyclone and 24 post-cyclone spotlighting surveys at a site with severe cyclone damage, and 18 post-cyclone surveys at a site with minor damage. We detected a greater number of lemuroid, Hemibelideus lemuroides and green, Pseudochirops archeri, ringtail possums as these possums remained in the severely damaged canopy and forest edge. In contrast, Herbert River ringtail possums, Pseudochirulus herbertensis, were detected in smaller numbers. We radio-tracked eight P. herbertensis before the cyclone, following two of these and nine new animals after the category 4 cyclone. No significant post-cyclone alteration in home range area or span was recorded in data pooled across the two sites or in limited post-cyclone data at the severely disturbed site, but a greater variability in home range was observed after cyclone (pooled across sites: 1.72 ± 0.77 ha; 197 ± 47 m) than before the cyclone (1.35 ± 0.30 ha; 196 ± 23 m). In contrast, pooled pre- and post-cyclone home range areas and spans were larger at the severely-disturbed site (2.08 ± 0.56 ha; 231 ± 32 m) than at the site with minor damage (0.68 ± 0.11 ha; 114 ± 25 m), suggesting resources were more widely spread at the former site. Post-cyclone home ranges were also larger at the severely damaged site (severe: 3.33 ± 1.36 ha, n = 3; minor: 0.52 ± 0.07 ha, n = 4). Condition of P. herbertensis (mass/tail length) did not differ significantly pre- and post-cyclone or between less and severely disturbed sites. These results and observations of breeding after cyclone suggest that possum populations may be resilient to severe cyclone damage under the relatively wet conditions experienced post-Cyclone Larry. [source] | |||||||||||||