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- Author or Editor: Richard W. Nelson x
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Abstract
Objective—To compare aesthesiometer-determined corneal sensitivity between diabetic and nondiabetic dogs and to investigate the correlation between corneal sensitivity and duration of diabetes or status of glycemic control, as estimated by use of glycated blood protein concentrations.
Animals—23 diabetic and 29 nondiabetic normoglycemic dogs.
Procedure—A Cochet-Bonnet aesthesiometer was used to measure corneal touch threshold (CTT) in 5 corneal regions of each dog. At the time of ocular examination, duration of diabetes mellitus was estimated from the history, and blood was drawn for assessment of blood glycosylated hemoglobin and serum fructosamine concentrations.
Results—Median CTT for central, nasal, dorsal, temporal, and ventral corneal regions in nondiabetic dogs (1.6, 2.3, 2.8, 2.8, and 5.1 g/mm2, respectively) was significantly lower than in diabetic dogs (2.8, 4.0, 5.1, 5.1, and 6.6 g/mm2, respectively). Median regional CTT in diabetic dogs was not significantly correlated with estimated duration of diabetes mellitus or blood glycated protein concentrations. No significant difference was found in regional CTT between eyes of normoglycemic dogs with unilateral cataracts.
Conclusion and Clinical Relevance—Diabetic dogs have significantly reduced corneal sensitivity in all regions, compared with nondiabetic normoglycemic dogs. Regional variation in corneal sensitivity is similar in diabetic and normoglycemic dogs. Neither glycemic control nor duration of diabetes, as estimated, is significantly correlated with corneal hyposensitivity. Corneal nerve dysfunction may be associated with recurrent or nonhealing ulcers in diabetic dogs for which no other underlying cause can be found. (Am J Vet Res 2003;64:7–11)
Abstract
Objective—To determine toxic effects of streptozocin given in combination with a diuresis protocol in dogs and establish whether streptozocin is efficacious in treatment of pancreatic islet cell tumors in dogs.
Design—Retrospective study.
Animals—17 dogs.
Procedure—Medical records were reviewed to obtain information regarding signalment, tumor stage and staging tests performed, number of streptozocin treatments, adverse effects, results of biochemical and hematologic monitoring during streptozocin treatment, tumor dimensions, duration of normoglycemia, and date of death, when applicable. Dogs were compared with a historical control group of 15 dogs treated surgically and medically.
Results—58 treatments were administered to the 17 dogs. Only 1 dog developed azotemia. Serum alanine aminotransferase activity increased in some dogs but decreased when treatment was discontinued. Hematologic toxicoses were rare. Vomiting during administration was uncommon but occasionally severe. Two dogs developed diabetes mellitus after receiving 5 doses. Median duration of normoglycemia for 14 dogs with stage-II or -III insulinoma treated with streptozocin was 163 days (95% confidence interval, 16 to 309 days), which was not significantly different from that for the control dogs (90 days; 95% confidence interval, 0 to 426 days). Two dogs had rapid resolution of paraneoplastic peripheral neuropathy, and 2 others had measurable reductions in tumor size.
Conclusions and Clinical Relevance—Results suggest that streptozocin can be administered safely to dogs at a dosage of 500 mg/m2, IV, every 3 weeks when combined with a protocol for induction of diuresis and may be efficacious in the treatment of dogs with metastatic pancreatic islet cell tumors. (J Am Vet Med Assoc 2002;221:811–818)
Abstract
Objective—To compare the sensitivity and specificity of serologic evaluation and fungal culture of tissue for diagnosis of nasal aspergillosis in dogs.
Design—Prospective study.
Animals—58 dogs with nasal discharge and 26 healthy dogs.
Procedures—Dogs with nasal discharge were anesthetized and underwent computed tomography and rhinoscopy; nasal tissues were collected for histologic examination and fungal culture. Sera were assessed for antibodies against Aspergillus spp (healthy dog sera were used as negative control specimens). Nasal aspergillosis was diagnosed in dogs that had at least 2 of the following findings: computed tomographic characteristics consistent with aspergillosis, fungal plaques detected during rhinoscopy, and histologically detectable fungal hyphae in nasal tissue. Histologic characteristics of malignancy were diagnostic for neoplasia. Without evidence of neoplasia or fungal disease, nonfungal rhinitis was diagnosed.
Results—Among the 58 dogs, 21 had nasal aspergillosis, 25 had nonfungal rhinitis, and 12 had nasal neoplasia. Fourteen aspergillosis-affected dogs and 1 dog with nonfungal rhinitis had serum antibodies against Aspergillus spp. Fungal culture results were positive for Aspergillus spp only for 17 dogs with aspergillosis. With regard to aspergillosis diagnosis, sensitivity, specificity, and positive and negative predictive values were 67%, 98%, 93%, and 84%, respectively, for serum anti-Aspergillus antibody determination and 81%, 100%, 100%, and 90%, respectively, for fungal culture.
Conclusions and Clinical Relevance—Results suggest that seropositivity for Aspergillus spp and identification of Aspergillus spp in cultures of nasal tissue are highly suggestive of nasal aspergillosis in dogs; however, negative test results do not rule out nasal aspergillosis.
Abstract
Objective—To evaluate the reliability of history and physical examination findings for assessing control of glycemia in insulin-treated diabetic dogs.
Design—Retrospective study.
Animals—53 insulin-treated dogs with diabetes mellitus.
Procedure—Medical records of insulin-treated diabetic dogs from June 1995 to June 1998 were reviewed, and information on owner perception of their dog's response to insulin treatment, physical examination findings, body weight, insulin dosage, and concentrations of food-withheld (ie, fasting) blood glucose (FBG), mean blood glucose (MBG) during an 8-hour period, blood glycosylated hemoglobin (GHb), and serum fructosamine was obtained. Owner's perception of their dog's response to insulin treatment, physical examination findings, and changes in body weight were used to classify control of glycemia as good or poor for each dog. The FBG, MBG/8 h, blood GHb, and serum fructosamine concentrations were compared between well-controlled and poorly controlled insulin-treated diabetic dogs.
Results—Presence or absence of polyuria, polydipsia, polyphagia, lethargy, and weakness were most helpful in classifying control of glycemia. Mean FBG and MBG/8 h concentrations, blood GHb concentrations, and serum fructosamine concentrations were significantly decreased in 25 well-controlled diabetic dogs, compared with 28 poorly controlled diabetic dogs. Most well-controlled diabetic dogs had concentrations of FBG between 100 and 300 mg/dl, MBG/8 h ≤ 250 mg/dl, blood GHb ≤ 7.5%, and serum fructosamine ≤ 525 µmol/L, whereas most poorly controlled diabetic dogs had results that were greater than these values.
Conclusion and Clinical Relevance—Reliance on history, physical examination findings, and changes in body weight are effective for initially assessing control of glycemia in insulin-treated diabetic dogs. (J Am Vet Med Assoc 2000;217:48–53)
Abstract
Objective—To determine prevalence of pituitary tumors, detectable by means of computed tomography or magnetic resonance imaging, in cats with insulin resistance suspected to have acromegaly or hyperadrenocorticism versus cats with well-controlled diabetes mellitus.
Design—Case series.
Animals—16 cats with insulin resistance that were also suspected to have acromegaly (n = 12) or pituitary-dependent hyperadrenocorticism (4) and 8 cats with well-controlled diabetes mellitus.
Procedure—Computed tomography was performed on all 16 cats with insulin resistance and 2 cats in which diabetes mellitus was well-controlled. The remaining 6 cats in which diabetes mellitus was wellcontrolled underwent magnetic resonance imaging. Images were obtained before and immediately after IV administration of contrast medium.
Results—Computed tomography revealed a mass in the region of the pituitary gland in all 16 cats with insulin resistance. Maximum width of the masses ranged from 4.4 to 12.7 mm; maximum height ranged from 3.1 to 12.6 mm. Results of computed tomography performed on 2 cats with well-controlled diabetes and magnetic resonance imaging performed on the remaining 6 cats were considered normal.
Conclusions and Clinical Relevance—Results suggest that cats with insulin resistance suspected to have acromegaly or pituitary-dependent hyperadrenocorticism are likely to have a pituitary mass detectable by means of computed tomography or magnetic resonance imaging. (J Am Vet Med Assoc 2000;216: 1765–1768)
Abstract
Objective—To evaluate the efficacy and safety of ultrasonographically guided radiofrequency heat ablation of parathyroid masses in dogs with primary hyperparathyroidism.
Design—Clinical trial.
Animals—11 dogs.
Procedure—In all dogs, either 1 or 2 parathyroid masses were evident ultrasonographically. Dogs were anesthetized, and a 20-gauge over-the-needle catheter was directed into the parathyroid mass via ultrasonographic guidance. Radiofrequency heat was applied to the stylet of the catheter until there was sonographically apparent change to the entire parenchyma of the mass. Serum total and ionized calcium and parathyroid hormone concentrations were monitored daily for 5 days after the ablation procedure and again at 1, 2, and 3-month intervals, if possible. Dogs were monitored for adverse effects.
Results—One treatment was required in 6 dogs, 2 treatments were required in 2 dogs, and treatment was unsuccessful in 3 dogs. Serum total and ionized calcium concentrations were within reference ranges within 2 days of the last procedure in all 8 successfully treated dogs. Serum parathyroid hormone concentration was decreased 24 hours after treatment in all 8 dogs. Hypocalcemia developed in 5 of the 8 successfully treated dogs, all of which required treatment. One dog had a transient voice change. Other adverse effects were not reported.
Conclusions and Clinical Relevance—Ultrasonographically guided radiofrequency heat ablation of parathyroid masses is a safe and effective alternative to surgery in dogs with primary hyperparathyroidism. (J Am Vet Med Assoc 2001;218:1106–1110)
Abstract
Objective—To evaluate effects of protamine zinc insulin (PZI) on control of glycemia in cats with newly diagnosed diabetes mellitus or poorly controlled diabetes.
Design—Clinical trial.
Animals—67 diabetic cats.
Procedure—34 cats with newly diagnosed diabetes and 33 cats with poorly controlled diabetes were treated with PZI twice daily for 45 days. Control of glycemia was assessed on days 7, 14, 30, and 45 by evaluation of clinical response, change in body weight, serum fructosamine concentration, blood glucose concentration measured 1, 3, 5, 7, and 9 hours after administration of PZI, lowest blood glucose concentration, and mean blood glucose concentration during the 9-hour period after administration. Adjustments in dosage of PZI were made as needed to attain control of glycemia.
Results—For all cats, a significant increase in mean dosage of PZI and significant decreases in 9-hour mean blood glucose concentration, lowest mean blood glucose concentration, and mean serum fructosamine concentration were detected. For cats with poorly controlled diabetes, 9-hour mean blood glucose concentration and mean serum fructosamine concentration were significantly decreased on day 45, compared with day 0. Ninety percent of owners reported improvement or resolution of clinical signs by day 45.
Conclusions and Clinical Relevance—Results suggest that PZI was effective for control of glycemia in cats with newly diagnosed or poorly controlled diabetes and may be used as an initial treatment or as an alternative treatment in cats that do not respond to treatment with other types of insulin. ( J Am Vet Med Assoc 2001;218:38–42)
Abstract
Objective—To evaluate accuracy of 6 portable blood glucose meters (PBGMs) by comparing results of these meters with results obtained with a reference chemistry analyzer.
Design—Evaluation study.
Animals—49 dogs (158 blood samples).
Procedures—Venous blood samples were tested with the 6 PBGMs, and results were compared with results of a commercially available analyzer that used a reference method based on the hexokinase reaction.
Results—Plasma glucose concentrations obtained with the reference analyzer ranged from 41 to 639 mg/dL. There were significant correlations between blood glucose concentrations obtained with the 6 PBGMs and plasma glucose concentrations obtained with the reference analyzer (r ≥ 0.96). However, for all 6 PBGMs, results differed from results for the reference analyzer, with the difference increasing as plasma glucose concentration increased. Significant differences in bias were found among meters. For 142 samples classified as hypoglycemic, euglycemic, or hyperglycemic on the basis of results of the reference analyzer, the percentage of samples that were misclassified on the basis of results of the PBGMs ranged from 2.1% to 38.7%.
Conclusions and Clinical Relevance—Results of the present study suggested that there were substantial differences in the accuracy of currently available PBGMs when used to determine blood glucose concentration in dogs.
Abstract
Objective—To determine the effects of racing and nontraining on plasma thyroxine (T4), free thyroxine (fT4), thyroid-stimulating hormone (TSH), and thyroglobulin autoantibody (TgAA) concentrations in sled dogs and compare results with reference ranges established for dogs of other breeds.
Design—Cross-sectional study.
Animals—122 sled dogs.
Procedure—Plasma thyroid hormone concentrations were measured before dogs began and after they finished or were removed from the Iditarod Trail Sled Dog Race in Alaska and approximately 3 months after the race.
Results—Concentrations of T4 and fT4 before the race were less than the reference range for nonsled dogs in 26% and 18% of sled dogs, respectively. Immediately after racing, 92% of sled dogs had plasma T4 concentrations less than the reference range. Three months after the race, 25% of sled dogs had plasma T4 concentrations less than the reference range. For T4, fT4, TSH, and TgAA, significant differences were not detected in samples collected before the race versus 3 months later.
Conclusions and Clinical Relevance—Plasma T4, fT4, and TSH concentrations decreased in dogs that complete a long distance sled dog race. Many clinically normal sled dogs have plasma T4 and fT4 values that are lower than the reference range for nonsled dogs. We suggest that the reference ranges for sled dogs are 5.3 to 40.3 nmol/L and 3.0 to 24.0 pmol/L for plasma T4 and fT4 concentrations, respectively, and 8.0 to 37.0 mU/L for TSH. (J Am Vet Med Assoc 2004;224:226–231)
Abstract
Objective—To determine efficacy and safety of percutaneous radiofrequency heat ablation for treatment of hyperthyroidism in cats.
Design—Prospective study.
Animals—9 cats.
Procedure—Hyperthyroidism was diagnosed via clinical signs and high serum total (TT4) and free thyroxine (fT4) concentrations. One or 2 hyperfunctional cervical thyroid nodules were detected by use of scintigraphy and ultrasonography. If cats had 1 abnormal thyroid lobe, heat ablation was performed on that lobe; if cats had 2 abnormal lobes, heat ablation was applied to the larger lobe. Overall, heat ablation was performed 14 times in the 9 cats. Clinical signs and serum TT4, fT4, and calcium concentrations were monitored daily for 2 days after the procedure, weekly for the first month, and then monthly. Laryngeal function was evaluated and cervical ultrasonography and thyroid scintigraphy were also performed. Monitoring continued for as long as 9 months after heat ablation if a cat became euthyroid or until an owner chose an alternative treatment because of recurrence of hyperthyroidism.
Results—Serum TT4 and fT4 concentrations transiently decreased after all 14 heat ablation procedures (≤ reference range after 10 of 14 treatments) within 2 days after the procedure. Cats were euthyroid for 0 to 18 months (mean, 4 months). Hyperthyroidism recurred in all cats. Adverse effects included transient Horner's syndrome (2 cats) and laryngeal paralysis without clinical signs (1 cat).
Conclusions and Clinical Relevance—Percutaneous heat ablation as a treatment for hyperthyroidism in cats is effective transiently but not permanently. (J Am Vet Med Assoc 2003;223:1602–1607)