The Experts below are selected from a list of 12 Experts worldwide ranked by ideXlab platform
Karen Lisa Hulme-moir - One of the best experts on this subject based on the ideXlab platform.
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Structure and Function of Leukocytes in the Family Macropodidae
2020Co-Authors: Karen Lisa Hulme-moirAbstract:Leukocytes play a central role in protecting the body against infectious organisms and their research is essential for understanding the mechanisms of immunity. By studying Leukocytes across a range of species, insights are provided into differing strategies employed to ensure resistance to disease. Surprisingly, the Structure and function of marsupial Leukocytes has received very limited study. Marsupials represent a major evolutionary pathway with distinct differences in reproduction and development from placental mammals. These differences in the life history of marsupials place unique challenges on the immune system, and differences in Leukocyte Structure and function could be reasonably expected. In this thesis, studies were undertaken to examine the cytochemical, ultrastructural and functional features of Leukocytes from species of marsupials, belonging to the family Macropodidae (kangaroos and wallabies). The aim of these studies was to elucidate the characteristics of macropodid Leukocytes and to compare and contrast these features with the known characteristics of other mammalian Leukocytes. Leukocytes from two species of macropodid, the tammar wallaby (Macropus eugenii) and the western grey kangaroo (Macropus fuliginosis), formed the basis of this study with additional material provided from quokka (Setonix brachyurus), woylie (Bettongia pencillata) and red kangaroo (Macropus rufus). Staining characteristics of cells were examined following reaction with Sudan black B, peroxidase, chloroacetate esterase, naphthyl butyrate esterase, alkaline phosphatase and periodic acid-Schiff. Peroxidase and Sudan Black B reactions were similar to domestic animal species but chloroacetate esterase and naphthyl butyrate esterase were unreliable as markers for macropodid neutrophils and monocytes, respectively. Significant variation in staining for alkaline phosphatase was seen between species of macropodid. Tammar wallabies and quokka demonstrated strong neutrophil alkaline phosphatase activity whereas western grey kangaroos, red kangaroos and woylies contained no activity within their Leukocytes. Peroxidase and alkaline phosphatase cytochemistry were also assessed at the ultrastructural level with transmission electron microscopy. This allowed the identification of distinct granule populations within macropodid neutrophils. Two subcellular compartments containing alkaline phosphatase activity were identified within tammar wallaby neutrophils. These were considered equivalent to secretory vesicles and a subpopulation of specific granules. Tubular vesicles containing alkaline phosphatase were also identified within the eosinophils of tammar wallabies. These Structures were a novel finding having not been reported previously in the eosinophils of other animal species. In addition to cytochemistry, the general ultraStructure of Leukocytes from tammar wallabies and western grey kangaroos were reported. Results were similar to previous reports for other marsupial species. The current body of knowledge was extended by the first detailed description of the ultraStructure of basophils in a marsupial. To assess functional aspects of macropdid neutrophils, flow cytometric assays were performed examining oxidative burst responses and phagocytosis. Reactive oxygen species were generated by neutrophils from tammar wallabies and western grey kangaroos in response to phorbol 12-myristate 13-acetate but not N-formyl-Met-Leu-Phe or opsonised bacteria. Phagocytosis of opsonised bacteria was also measured in neutrophils from tammar wallabies, which was poor in contrast to ovine neutrophils. However, flow cytometric studies were limited by sample preparation. Further optimisation of isolation methods for tammar wallaby Leukocytes should be undertaken before dogmatic conclusions are drawn. Overall, the results of this thesis demonstrate that, in the areas examined, the general characteristics of Leukocyte Structure and function of mammals are present in macropodids. However differences were identified both within and outside of the macropodid group. These differences have important ramifications for the use of ‘model’ species in the study of Leukocyte biology in marsupials. The results also provide potentially useful tools for the clinical diagnosis of haematological disease in macropodids and may be of interest to those studying comparative and evolutionary aspects of Leukocyte Structure and function.
Janet M. Lanyon - One of the best experts on this subject based on the ideXlab platform.
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Hematology of dugongs (Dugong dugon) in southern Queensland
Veterinary Clinical Pathology, 2015Co-Authors: Lucy Woolford, Arthur Wong, Helen L. Sneath, Trevor Long, Susan P. Boyd, Janet M. LanyonAbstract:Background: Little is known of the hematology of the dugong (Dugong dugon), a secretive and endangered coastal marine mammal. Objectives: This paper reports hematologic reference intervals (RI) for dugongs and characterizes morphologic, cytochemical, and ultrastructural features of dugong Leukocytes. Methods: Blood was collected from live, apparently healthy dugongs and analyzed using Cell-Dyn 3700 or Sysmex XT-2000iV hematology analyzers. Blood films were subjected to a series of cytochemical stains, and Leukocyte Structure was examined using transmission electron microscopy. Results: Reference intervals were established for 14 hematologic variables, total solids, and fibrinogen for 92 dugongs. Significant differences in some variables were found for animal size class, sex, and pregnancy status, and between analyzers. Subadults had higher Leukocyte and lymphocyte counts than adults. Males had higher total solids and fibrinogen than females. Pregnant females had higher HCT, MCV, and circulating nucleated RBC, and lower platelet counts than nonpregnant females. Lymphocytes were usually the predominant circulating Leukocyte. Heterophil cytoplasmic granules were abundant, fine, round to ovoid, and intensely eosinophilic, and round to ovoid or rod-shaped, and variably electron dense in electron microscopy. Eosinophils contained larger round eosinophilic to orange cytoplasmic granules, which ultrastructurally were bicompartmental with a round eccentric electron-dense core. Cytochemical staining of dugong heterophils suggests biochemical similarity to those of manatees and elephants, and for eosinophils, similarity to those of elephants, ruminants, and equids. Conclusions: Generation of hematologic RI and characterization of Leukocyte morphology improves evaluation of dugong health across this population and serves as a reference for other populations outside southern Queensland.
Lucy Woolford - One of the best experts on this subject based on the ideXlab platform.
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Hematology of dugongs (Dugong dugon) in southern Queensland
Veterinary Clinical Pathology, 2015Co-Authors: Lucy Woolford, Arthur Wong, Helen L. Sneath, Trevor Long, Susan P. Boyd, Janet M. LanyonAbstract:Background: Little is known of the hematology of the dugong (Dugong dugon), a secretive and endangered coastal marine mammal. Objectives: This paper reports hematologic reference intervals (RI) for dugongs and characterizes morphologic, cytochemical, and ultrastructural features of dugong Leukocytes. Methods: Blood was collected from live, apparently healthy dugongs and analyzed using Cell-Dyn 3700 or Sysmex XT-2000iV hematology analyzers. Blood films were subjected to a series of cytochemical stains, and Leukocyte Structure was examined using transmission electron microscopy. Results: Reference intervals were established for 14 hematologic variables, total solids, and fibrinogen for 92 dugongs. Significant differences in some variables were found for animal size class, sex, and pregnancy status, and between analyzers. Subadults had higher Leukocyte and lymphocyte counts than adults. Males had higher total solids and fibrinogen than females. Pregnant females had higher HCT, MCV, and circulating nucleated RBC, and lower platelet counts than nonpregnant females. Lymphocytes were usually the predominant circulating Leukocyte. Heterophil cytoplasmic granules were abundant, fine, round to ovoid, and intensely eosinophilic, and round to ovoid or rod-shaped, and variably electron dense in electron microscopy. Eosinophils contained larger round eosinophilic to orange cytoplasmic granules, which ultrastructurally were bicompartmental with a round eccentric electron-dense core. Cytochemical staining of dugong heterophils suggests biochemical similarity to those of manatees and elephants, and for eosinophils, similarity to those of elephants, ruminants, and equids. Conclusions: Generation of hematologic RI and characterization of Leukocyte morphology improves evaluation of dugong health across this population and serves as a reference for other populations outside southern Queensland.
Bryan Larsen - One of the best experts on this subject based on the ideXlab platform.
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Effect of gliotoxin on human polymorphonuclear neutrophils.
Infectious Diseases in Obstetrics & Gynecology, 1998Co-Authors: D.t. Shah, Susan H. Jackman, J. Engle, Bryan LarsenAbstract:OBJECTIVES: Candida albicans is known to produce gliotoxin, which has several prominent biological effects, including immunosuppression. Interference with host defenses may arise from the effects of this toxin on Leukocyte Structure and function. METHODS: Flow cytometric analysis revealed that polymorphonuclear Leukocytes (PMN) were more sensitive to gliotoxin than were mononuclear cells. Structural and various functional aspects of PMN exposed to gliotoxin were studied. RESULTS: Gliotoxin at (1 microgram/mL) did not affect the viability but did diminish PMN chemotaxis and reduced their ability to ingest particles. Other functional aberrations included decreased nitroblue tetrazolium dye reduction, decreased superoxide production, and release of lactoferrin suggesting by degranulation. Gliotoxin also affected the ability of PMN to kill Escherichia coli. CONCLUSIONS: This study suggests a previously unrecognized potential virulence factor of C. albicans that could contribute to persistence of yeast colonization or recurrence of symptomatic infection through diminished host resistance.
Arthur Wong - One of the best experts on this subject based on the ideXlab platform.
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Hematology of dugongs (Dugong dugon) in southern Queensland
Veterinary Clinical Pathology, 2015Co-Authors: Lucy Woolford, Arthur Wong, Helen L. Sneath, Trevor Long, Susan P. Boyd, Janet M. LanyonAbstract:Background: Little is known of the hematology of the dugong (Dugong dugon), a secretive and endangered coastal marine mammal. Objectives: This paper reports hematologic reference intervals (RI) for dugongs and characterizes morphologic, cytochemical, and ultrastructural features of dugong Leukocytes. Methods: Blood was collected from live, apparently healthy dugongs and analyzed using Cell-Dyn 3700 or Sysmex XT-2000iV hematology analyzers. Blood films were subjected to a series of cytochemical stains, and Leukocyte Structure was examined using transmission electron microscopy. Results: Reference intervals were established for 14 hematologic variables, total solids, and fibrinogen for 92 dugongs. Significant differences in some variables were found for animal size class, sex, and pregnancy status, and between analyzers. Subadults had higher Leukocyte and lymphocyte counts than adults. Males had higher total solids and fibrinogen than females. Pregnant females had higher HCT, MCV, and circulating nucleated RBC, and lower platelet counts than nonpregnant females. Lymphocytes were usually the predominant circulating Leukocyte. Heterophil cytoplasmic granules were abundant, fine, round to ovoid, and intensely eosinophilic, and round to ovoid or rod-shaped, and variably electron dense in electron microscopy. Eosinophils contained larger round eosinophilic to orange cytoplasmic granules, which ultrastructurally were bicompartmental with a round eccentric electron-dense core. Cytochemical staining of dugong heterophils suggests biochemical similarity to those of manatees and elephants, and for eosinophils, similarity to those of elephants, ruminants, and equids. Conclusions: Generation of hematologic RI and characterization of Leukocyte morphology improves evaluation of dugong health across this population and serves as a reference for other populations outside southern Queensland.