The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform
John M Kreeger - One of the best experts on this subject based on the ideXlab platform.
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diabetes mellitus in a domesticated Spanish Mustang
Javma-journal of The American Veterinary Medical Association, 2005Co-Authors: Philip J Johnson, Nicole C Scotty, Charles E Wiedmeyer, Nat T Messer, John M KreegerAbstract:: An 18-year-old Spanish Mustang mare was referred for evaluation of progressive weight loss and persistent hyperglycemia. Clinicopathologic abnormalities included marked hyperglycemia and glycosuria. Serum cortisol concentration was appropriately decreased following administration of dexamethasone, indicating that the horse did not have pituitary pars intermedia dysfunction. Serum insulin and plasma C-peptide concentrations were low, suggesting that hyperglycemia was a result of decreased secretion of insulin by pancreatic beta cells. In addition, glucose concentration did not return to the baseline concentration until 5 hours after i.v. administration of a glucose bolus, suggesting that insulin secretion, insulin effect, or both were reduced. However, i.v. administration of insulin caused only a slight decrease in the plasma glucose concentration, giving the impression that the action of insulin was impaired. Within 5 hours after administration of a combination of glyburide and metformin, which is used to treat diabetes mellitus in humans, the glucose concentration was within reference limits. The horse was euthanized, and a postmortem examination was done. Immunohistochemical staining of sections of the pancreas revealed attenuation of the pancreatic islet beta-cell population, with beta cells that remained generally limited to the periphery of the islets. These findings indicate that, albeit rare, pancreatic beta-cell failure may contribute to the development of diabetes mellitus in horses.
Philip J Johnson - One of the best experts on this subject based on the ideXlab platform.
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diabetes mellitus in a domesticated Spanish Mustang
Javma-journal of The American Veterinary Medical Association, 2005Co-Authors: Philip J Johnson, Nicole C Scotty, Charles E Wiedmeyer, Nat T Messer, John M KreegerAbstract:: An 18-year-old Spanish Mustang mare was referred for evaluation of progressive weight loss and persistent hyperglycemia. Clinicopathologic abnormalities included marked hyperglycemia and glycosuria. Serum cortisol concentration was appropriately decreased following administration of dexamethasone, indicating that the horse did not have pituitary pars intermedia dysfunction. Serum insulin and plasma C-peptide concentrations were low, suggesting that hyperglycemia was a result of decreased secretion of insulin by pancreatic beta cells. In addition, glucose concentration did not return to the baseline concentration until 5 hours after i.v. administration of a glucose bolus, suggesting that insulin secretion, insulin effect, or both were reduced. However, i.v. administration of insulin caused only a slight decrease in the plasma glucose concentration, giving the impression that the action of insulin was impaired. Within 5 hours after administration of a combination of glyburide and metformin, which is used to treat diabetes mellitus in humans, the glucose concentration was within reference limits. The horse was euthanized, and a postmortem examination was done. Immunohistochemical staining of sections of the pancreas revealed attenuation of the pancreatic islet beta-cell population, with beta cells that remained generally limited to the periphery of the islets. These findings indicate that, albeit rare, pancreatic beta-cell failure may contribute to the development of diabetes mellitus in horses.
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Methemoglobinemia and eccentrocytosis in equine erythrocyte flavin adenine dinucleotide deficiency.
Veterinary Pathology, 2003Co-Authors: J. W. Harvey, Philip J Johnson, Steven L. Stockham, Michael A. Scott, J. J. Donald, C. J. ChandlerAbstract:This report describes erythrocyte biochemical findings in an adult Spanish Mustang mare that exhibited persistent methemoglobinemia, eccentrocytosis, and pyknocytosis that were not related to the con- sumption or administration of an exogenous oxidant. The methemoglobinemia was attributed to a deficiency in cytochrome-b5 reductase (Cb5R) activity, and the eccentrocytes and pyknocytes were attributed to a marked deficiency in reduced nicotinamide adenine dinucleotide phosphate-dependent glutathione reductase (GR) ac- tivity that resulted in decreased reduced glutathione concentration within erythrocytes. The GR activity increased to a near-normal value after addition of flavin adenine dinucleotide (FAD) to the enzyme assay, indicating a deficiency of FAD in erythrocytes. The methemoglobinemia, eccentrocytosis, and pyknocytosis were attributed to deficiency of FAD in erythrocytes because the GR and Cb 5R enzymes use FAD as a cofactor. This deficiency in FAD results from a defect in erythrocyte riboflavin metabolism, which has not been documented previously in animals.
Patricia M. Gaffney - One of the best experts on this subject based on the ideXlab platform.
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Insulin-dependent diabetes mellitus associated with presumed autoimmune polyendocrine syndrome in a mare
Canadian Veterinary Journal-revue Veterinaire Canadienne, 2011Co-Authors: Jill K. Giri, K G Magdesian, Patricia M. GaffneyAbstract:Diabetes mellitus (DM) is associated with persistent hyperglycemia due to deficient production of or reduced sensitivity to insulin (1). Diabetes is classified into insulin-dependent diabetes mellitus (IDDM or type 1) and noninsulin-dependent diabetes mellitus (NIDDM or type 2). Other categories in humans include secondary diabetes mellitus (type S), impaired glucose tolerance (IGT), and gestational diabetes (1,2). Diabetes mellitus is uncommon in horses and the few reported cases have included insulin resistant and type S DM, secondary to pituitary-dependent hyperadrenocorticism (1,3–11). Other reported causes of diabetes in horses include chronic pancreatitis, granulosa cell ovarian tumor, and pregnancy (1,6,8,11). Type I diabetes is even less common in horses (3,6). Johnson et al (3) recently reported a case of IDDM in a Spanish Mustang mare, diagnosed with an abnormally low serum insulin concentration [21 pmol/L, reference interval (RI): 30 to 300 pmol/L] in the face of persistent hyperglycemia (20.2 mmol/L, RI: 4.0 to 6.3 mmol/L) (3). Insulin-dependent diabetes mellitus occurs as a result of insulin deficiency due to destruction of pancreatic beta cells; in humans this usually progresses to a state of absolute insulin deficiency (2). In most human patients, an autoimmune process is thought to play a significant role in the development of IDDM (2). Insulin-dependent diabetes mellitus is successfully managed in several species, most notably humans, dogs, and cats. Of the many challenges in the treatment of IDDM in horses, among the most significant is the paucity of clinical and reported experience with long-term administration of insulin, the absence of monitoring tools, and little experience regarding dietary and exercise management.
Nat T Messer - One of the best experts on this subject based on the ideXlab platform.
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diabetes mellitus in a domesticated Spanish Mustang
Javma-journal of The American Veterinary Medical Association, 2005Co-Authors: Philip J Johnson, Nicole C Scotty, Charles E Wiedmeyer, Nat T Messer, John M KreegerAbstract:: An 18-year-old Spanish Mustang mare was referred for evaluation of progressive weight loss and persistent hyperglycemia. Clinicopathologic abnormalities included marked hyperglycemia and glycosuria. Serum cortisol concentration was appropriately decreased following administration of dexamethasone, indicating that the horse did not have pituitary pars intermedia dysfunction. Serum insulin and plasma C-peptide concentrations were low, suggesting that hyperglycemia was a result of decreased secretion of insulin by pancreatic beta cells. In addition, glucose concentration did not return to the baseline concentration until 5 hours after i.v. administration of a glucose bolus, suggesting that insulin secretion, insulin effect, or both were reduced. However, i.v. administration of insulin caused only a slight decrease in the plasma glucose concentration, giving the impression that the action of insulin was impaired. Within 5 hours after administration of a combination of glyburide and metformin, which is used to treat diabetes mellitus in humans, the glucose concentration was within reference limits. The horse was euthanized, and a postmortem examination was done. Immunohistochemical staining of sections of the pancreas revealed attenuation of the pancreatic islet beta-cell population, with beta cells that remained generally limited to the periphery of the islets. These findings indicate that, albeit rare, pancreatic beta-cell failure may contribute to the development of diabetes mellitus in horses.
Charles E Wiedmeyer - One of the best experts on this subject based on the ideXlab platform.
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diabetes mellitus in a domesticated Spanish Mustang
Javma-journal of The American Veterinary Medical Association, 2005Co-Authors: Philip J Johnson, Nicole C Scotty, Charles E Wiedmeyer, Nat T Messer, John M KreegerAbstract:: An 18-year-old Spanish Mustang mare was referred for evaluation of progressive weight loss and persistent hyperglycemia. Clinicopathologic abnormalities included marked hyperglycemia and glycosuria. Serum cortisol concentration was appropriately decreased following administration of dexamethasone, indicating that the horse did not have pituitary pars intermedia dysfunction. Serum insulin and plasma C-peptide concentrations were low, suggesting that hyperglycemia was a result of decreased secretion of insulin by pancreatic beta cells. In addition, glucose concentration did not return to the baseline concentration until 5 hours after i.v. administration of a glucose bolus, suggesting that insulin secretion, insulin effect, or both were reduced. However, i.v. administration of insulin caused only a slight decrease in the plasma glucose concentration, giving the impression that the action of insulin was impaired. Within 5 hours after administration of a combination of glyburide and metformin, which is used to treat diabetes mellitus in humans, the glucose concentration was within reference limits. The horse was euthanized, and a postmortem examination was done. Immunohistochemical staining of sections of the pancreas revealed attenuation of the pancreatic islet beta-cell population, with beta cells that remained generally limited to the periphery of the islets. These findings indicate that, albeit rare, pancreatic beta-cell failure may contribute to the development of diabetes mellitus in horses.