Biomedical subjects

D L Panciera

Publications and source records attributed to D L Panciera.

At least 19 recordsLinked to original sources

PubMed2001

Conditions associated with canine hypothyroidism.

Careful review of the literature regarding clinical signs caused by hypothyroidism in dogs has shown that some assumptions regarding the relation of hypothyroidism to other conditions are based on anecdotal evidence. Cutaneous manifestations are present in most hypothyroid dogs, but the specific abnormalities and breed variations remain to be clearly defined. Decreased metabolic rate manifested by obesity and lethargy is also common. Neurologic manifestations, although uncommon, clearly occur in hypothyroid dogs. Cardiac abnormalities seem to be common, but their clinical significance is questionable. The only consistent hematologic abnormality that occurs in hypothyroid dogs is anemia; evidence for acquired von Willebrand's disease or other bleeding disorders is negligible. Reproductive dysfunction secondary to hypothyroidism is unlikely to occur in male dogs, and there is no evidence to support abnormalities in female dogs. The relation of megaesophagus, laryngeal paralysis, ocular abnormalities, and gastrointestinal disorders with hypothyroidism remains to be established. Future research into canine hypothyroidism may serve to convert dogma into a more clear understanding of the manifestations and pathophysiologic findings of this common endocrinopathy.

Anemia↗

PubMed1999

Is it possible to diagnose canine hypothyroidism?

A definitive diagnosis of hypothyroidism can be difficult because of the many clinical abnormalities associated with thyroid hormone deficiency, and the lack of readily available diagnostic tests with high sensitivity and specificity. Thyroid function tests should be performed only in dogs with clinical findings consistent with hypothyroidism. Measurement of serum total thyroxine (T4) concentration is a useful initial screening test since most hypothyroid dogs have values below the reference range. Serum free T4 concentration measured by equilibrium dialysis is a more sensitive and specific test of thyroid function than total T4 and is particularly useful in dogs with non-thyroidal illness or atypical clinical signs. Measurement of serum endogenous thyroid-stimulating hormone concentration is also helpful, but many hypothyroid dogs have normal results. The gold standard for diagnosis of hypothyroidism remains the thyroid-stimulating hormone response test. It should be used to confirm hypothyroidism when other tests do not agree with the clinical impression or if atypical signs or non-thyroidal illness exist or there has been administration of drugs known to alter thyroid function tests. Ultimately, a positive response to treatment is expected in hypothyroid dogs treated appropriately with levothyroxine.

Animals↗

PubMed1998

The effect of dehydroepiandrosterone combined with a low-fat diet in spontaneously obese dogs: a clinical trial.

Dehydroepiandrosterone (DHEA) has been shown to have antiobesity activity in rodents and spontaneously obese dogs. This study evaluated the effect of DHEA or placebo combined with a low-fat/high-fiber diet in spontaneously obese dogs in a clinical trial. Spontaneously obese, euthyroid dogs, referred to the University of Wisconsin School of Veterinary Medicine for treatment of their obesity, were evaluated for percent overweight, rate of weight loss, serum cholesterol, plasma lipoprotein and serum biochemistry profiles, complete blood count, and endocrine profiles (T4, T3, cortisol, insulin, and DHEA-sulfate). DHEA-treated dogs had a significantly increased rate of actual and percent excess weight loss compared with placebo-treated dogs. Serum cholesterol decreased in both treatment groups; however, DHEA-treated dogs had a significantly greater reduction than placebo-treated dogs. DHEA-treated dogs had a significant 32% reduction in total plasma cholesterol, which was due to a 27% reduction in the lipoprotein fraction containing the high-density lipoprotein (HDL) and a 50% reduction in the lipoprotein fraction containing the low-density lipoprotein (LDL). Placebo-treated dogs did not have a significant reduction in total plasma cholesterol or in the fraction containing LDL; however, they did have a significant 11% reduction in the fraction containing HDL. Significant decreases in serum T4 and T3 observed in dogs receiving DHEA were not noted in dogs receiving placebo. DHEA in combination with caloric restriction results in a faster rate of weight loss than does caloric restriction alone. In addition, DHEA has hypocholesterolemic activity, particularly affecting the lipoprotein fraction containing the LDL cholesterol.

Animals↗

PubMed1997

Insulin overdose in dogs and cats: 28 cases (1986-1993).

OBJECTIVE: To characterize the frequency, medical history, clinical signs, methods of treatment, and outcome of insulin-induced hypoglycemia and to identify predisposing factors. DESIGN: Retrospective study. ANIMALS: 8 dogs and 20 cats with diabetes mellitus that developed hypoglycemia because of insulin overdose. PROCEDURE: Medical records of dogs and cats receiving insulin for treatment of diabetes mellitus were reviewed. Medical records of dogs and cats that had an episode of hypoglycemia were reviewed in detail. RESULTS: Overdosing of insulin was more common in cats than in dogs. Median weight of diabetic cats that became hypoglycemic was significantly greater than that of the hospital population of diabetic cats at diagnosis. Eighty percent of cats that became hypoglycemic were receiving insulin doses > 6 U/injection, administered once or twice daily. Dose and type of insulin did not correlate with duration or severity of hypoglycemia. In 7 of 8 dogs and 10 of 20 cats, management factors or concurrent medical problems were considered to be predisposing causes for insulin overdose. Two dogs and 2 cats did not have clinical signs of hypoglycemia, despite documented low concentrations of glucose in their blood. CLINICAL IMPLICATIONS: Diabetic cats, especially if obese, are at greater risk of insulin overdose than are diabetic dogs. The reason for overdose may not be evident. Diabetic dogs and cats may become hypoglycemic without developing autonomic warning signs of hypoglycemia, or these signs may not be recognized (hypoglycemia unawareness).

Animals↗

PubMed1995

Acute effects of continuous infusions of human recombinant interleukin-2 on serum thyroid hormone concentrations in dogs.

The effect of human recombinant interleukin-2 (IL-2) on serum thyroid hormone concentrations in dogs was studied. Four normal adult dogs received two consecutive weekly cycles of continuous infusions of 3 x 10(6) U m-2 daily for four days per week (days 1 to 4 and 8 to 11). The serum concentrations of IL-2, thyroxine (T4) and 3, 5, 3'-triiodothyronine (T3) were measured before and on days 2, 3 and 4, and 9, 10 and 11 of the infusions. There was a significant decrease in the mean serum concentrations of T4 and T3 at all times during the infusion of IL-2; the serum T4 concentrations decreased by 50 to 75 per cent and serum T3 by 70 to 80 per cent of the pretreatment concentrations in all the dogs. No antithyroglobulin antibodies were detected in the serum of any of the dogs on days 10 and 11 of the infusions. The concentrations of circulating thyroid hormones decreased rapidly in the dogs during the infusion of IL-2, as in the euthyroid sick syndrome.

Animals↗

PubMed1994

Plasma von Willebrand factor antigen concentration in dogs with hypothyroidism.

Plasma von Willebrand factor antigen concentration was measured in 10 dogs with hypothyroidism, before and after administration of a replacement dose of levothyroxine for 67 +/- 12 days. Results were reported as a percentage of normal activity, with plasma pooled from clinically normal dogs given a value of 100%. Plasma von Willebrand factor antigen concentration was within reference limits in dogs with hypothyroidism (126 +/- 41%) and was significantly (P < 0.01) decreased (94 +/- 39%) after treatment with levothyroxine. Contrary to findings in some other studies, a deficiency of plasma von Willebrand factor did not appear to result from hypothyroidism.

Animals↗

PubMed1994

An echocardiographic and electrocardiographic study of cardiovascular function in hypothyroid dogs.

Echocardiograms and ECG were obtained for 11 hypothyroid dogs before and after levothyroxine supplementation (0.022 mg/kg of body weight, q 12 h for 64 +/- 12 days). Evidence of impaired left ventricular function was found in the dogs before treatment. A significant decrease in shortening fraction and velocity of circumferential fiber shortening, increase in left ventricular end-systolic diameter, and prolongation of preejection period was noted when comparing measurements before and after levothyroxine supplementation. Amplitude of the P and R waves was significantly higher after treatment than before. It was concluded that changes in cardiac function can be reversed in hypothyroid dogs.

Animals↗

PubMed1994

Hypothyroidism in dogs: 66 cases (1987-1992).

Sixty-six dogs with hypothyroidism were identified from dogs examined over a 5-year period. Hypothyroidism was diagnosed only if the dog had a low, resting serum thyroxine concentration and serum thyroxine concentration was not higher than the lower limits of the reference range 6 hours after IV administration of bovine thyrotropin. The prevalence of hypothyroidism was 0.2%. Neutering was determined to be the most significant gender-associated risk factor for development of hypothyroidism. Neutered male and spayed female dogs had a higher relative risk of developing hypothyroidism than did sexually intact females. Sexually intact females had a lower relative risk. Breeds with a significantly increased risk, compared with other breeds, were the Doberman Pinscher and Golden Retriever. The most common clinical findings were obesity (41%), seborrhea (39%), alopecia (26%), weakness (21%), lethargy (20%), bradycardia (14%), and pyoderma (11%). Low voltage R-waves were found on 58% of ECG. Clinicopathologic abnormalities included hypercholesterolemia (73%), nonregenerative anemia (32%), high serum alkaline phosphatase activity (30%), and high serum creatine kinase activity (18%). Serum total triiodothyronine concentrations were within reference ranges in 15% of the hypothyroid dogs. Response to treatment was good in most dogs, but those with severe concurrent disease or neurologic abnormalities were less likely to respond with complete resolution of clinical signs.

Animals↗

PubMed1994

Administration of vancomycin for treatment of ascending bacterial cholangiohepatitis in a cat.

A 12-year-old neutered male domestic shorthair cat, being treated with methimazole for hyperthyroidism, developed chronic cholangitis with portal fibrosis and chronic cholecystitis. The common bile duct was not patent, which necessitated cholecystojejunostomy. Four days after surgery, the cat developed suppurative cholangio-hepatitis caused by a beta-lactam resistant Enterococcus. The cat's condition was further complicated by the concurrent development of hypokalemic polymyopathy. On the basis of minimum inhibitory concentrations, the Enterococcus was determined to be susceptible to vancomycin and resistant to numerous antibiotics commonly used for treatment of infections caused by Enterococcus spp. The cat recovered without evidence of adverse effects attributable to vancomycin.

Animals↗

PubMed1994

Hypotensive shock syndrome associated with acute Babesia canis infection in a dog.

A Doberman Pinscher contracted babesiosis after receiving a fresh blood transfusion from a Greyhound blood donor. Hypotensive shock syndrome was suspected on the basis of arterial hypotension, weakness, and pyrexia in the absence of detectable hemolysis and within hours of detection of low numbers of circulating Babesia canis organisms. Treatment with imidocarb dipropionate appears to have been effective in eliminating circulating B canis organisms and clinical disease. The blood donor, recently acquired from a race track, was healthy and lacked any abnormalities on initial laboratory evaluation; however, its serum antibody titer for B canis was > 1:5,000; B canis organisms were later identified on blood smears after the dog had been splenectomized and treated with corticosteroids at an immunosuppressive dosage. This case draws attention to a potential problem in current screening practices for infectious diseases of retired racing Greyhounds intended for use as blood donors.

Acute Disease↗

PubMed1994

Pharmacokinetics and short-term clinicopathologic changes after intravenous administration of a high dose of methimazole in dogs.

A bolus dose of methimazole (MMI) was administered IV over 1 minute to 5 healthy adult dogs at a dosage (40 mg/kg of body weight) known to impart protection against cisplatin-induced renal disease. Blood and urine samples for pharmacokinetic analysis were collected over a 24-hour period. Physical examination, CBC, determination of serum thyroid hormone concentrations, and serum biochemistry analysis were performed over a 10-day period to evaluate short-term toxicoses. At this dosage, MMI appears to be safe and well tolerated in dogs; only 1 of the 5 dogs had mild and transient increases in serum activity of hepatic enzymes. In addition, MMI did not alter serum thyroid hormone concentrations. Half-life of 8.82 hours and mean residence time of 12.18 hours were determined for MMI. Renal clearance of native MMI, along with sulfate and glucuronide conjugates, represented only 20% of total systemic clearance. Results of this study provide further information concerning clinical use of MMI in dogs and may contribute to better understanding of the mechanism of MMI protection against chemically induced nephrotoxicosis.

Alanine Transaminase↗

PubMed1994

Thyroid function in dogs with spontaneous and induced congestive heart failure.

The effects of spontaneous and experimentally induced congestive heart failure on serum thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3'5'-triiodothyronine (reverse T3), free T4, free T3 concentrations, and the serum T4 and T3 concentrations in response to administration of thyrotropin were studied. Serum thyroid hormone concentrations were not different between eight dogs with spontaneous congestive heart failure and normal age matched control dogs. Seven dogs with experimental heart failure were tested before and after induction of congestive heart failure by rapid ventricular pacing. Mean serum T4 and free T3 concentrations were decreased and mean serum reverse T3 concentration was increased following induction of heart failure. The serum T4 and T3 responses to thyrotropin were not altered. Thyroid gland morphology appeared normal in dogs with experimental heart failure. Experimental congestive heart failure, similar to some other nonthyroidal illnesses, alters thyroid hormone secretion and metabolism in dogs.

Animals↗

PubMed1994

Effects of experimentally induced hypothyroidism on the eye and ocular adnexa of dogs.

Schirmer tear test (STT), intraocular pressure (IOP) measurement, slit-lamp biomicroscopy, and indirect ophthalmoscopy were performed on 8 dogs with 131I-induced hypothyroidism and 4 euthyroid control dogs at weeks 0, 9, 13, 17, immediately prior to treatment with levothyroxine, after 5 weeks of levothyroxine administration (0.022 mg/kg of body weight, PO, q 12 h), and at euthanasia 7 weeks after discontinuation of replacement therapy. Although the control group had higher baseline STT values than the hypothyroid group after randomization of dogs into the 2 groups (P < 0.01), STT values remained unchanged from their respective baseline values at all time intervals for both groups. Hypothyroid and control dogs had significant (P < 0.05) reduction in IOP from baseline values at all subsequent time points, but differences were not observed when hypothyroid dogs were compared with controls. Goblet cell indices determined from biopsy samples of the inferior-nasal conjunctival fornix obtained before induction of hypothyroidism (baseline), immediately prior to and at conclusion of levothyroxine therapy, and at euthanasia were not significantly different when values for hypothyroid dogs were compared with their own baseline values or with values for control dogs. Histologic examination of the globes and adnexa at euthanasia also failed to indicate consistent qualitative differences between hypothyroid and control dogs. Marked reduction in serum thyroid hormone concentrations had little effect on the eye and ocular adnexa over the course of the study.

Analysis of Variance↗

PubMed1993

Methimazole as a protectant against cisplatin-induced nephrotoxicity using the dog as a model.

The protective effect of methimazole, a commonly used antithyroid drug, on cisplatin-induced nephrotoxicity was studied. Eight dogs received 80 mg/m2 cisplatin i.v. without saline prehydration. Dogs were randomized into two groups of four dogs each: one group received 40 mg/kg methimazole i.p. at 30 min prior to and 4 h after cisplatin delivery, and the other group received saline placebo i.p. Methimazole protected dogs against the in vivo nephrotoxicity elicited by cisplatin as evidenced by clinicopathologic and histopathologic indices. Protection was not complete, as methimazole-treated animals developed mild histopathologic renal changes. Measures of renal oxidative stress did not differ between the two groups at day 5 following cisplatin treatment. No difference was noted for serum thyroxine concentrations before or after therapy in either group; however, serum levels of 3,5,3'-triiodothyronine were significantly higher on day 5 in both groups of dogs receiving cisplatin, regardless of whether they received methimazole or not. Methimazole as used in this study was found to be well tolerated in dogs over the short term, with no significant clinical or clinicopathologic toxicity being observed. The results of this study support the additional evaluation of methimazole as a protectant against cisplatin-induced nephrotoxicity using the dog as a model.

Animals↗

PubMed1993

Lack of effect of trimethoprim and sulfadiazine in combination in mid- to late gestation on thyroid function in neonatal dogs.

Four pregnant bitches were randomly selected and were given 25 mg sulfadiazine kg-1 and 5 mg trimethoprim kg-1 orally once daily, starting on day 29 of dioestrus until parturition. Five untreated pregnant bitches were used as controls. At the end of the treatment period (parturition = week 0), one to three pups of each litter, treatment and control group, were randomly selected and blood was obtained by cardiac puncture for serum thyroxine (T4) and triiodothyronine (T3) concentrations. These pups were then killed and the thyroids were harvested and examined histologically. This protocol was repeated three times at weekly intervals. There were no significant differences in mean T4 and T3 concentrations between treated and control groups at any time during the study. Mean concentration of serum T4 and T3 did increase significantly over the 3 weeks of study. Histologically, no significant differences in thyroid structure were observed between treated and control groups. The numbers of stillborn or weak pups did not increase in the treatment group. No differences were observed in the length of gestation between the treated and control groups. Administration of sulfadiazine and trimethoprim does not affect the thyroid gland in the neonate.

Animals↗

PubMed1992

Administration of levothyroxine to euthyroid dogs does not affect echocardiographic and electrocardiographic measurements.

The effects of a replacement dose of levothyroxine on electrocardiographic and echocardiographic parameters in euthyroid dogs were examined. Two-dimensional guided M-mode echocardiograms and electrocardiograms were obtained before and after administration of levothyroxine (0.5 mg m-2 twice a day) to 10 euthyroid dogs for a period of eight weeks; four untreated dogs acted as controls. The resting serum total thyroxine concentration was significantly increased in treated dogs during weeks 4 to 8. There were no significant differences in any of the echocardiographic or electrocardiographic measurements resulting from treatment.

Animals↗

PubMed1992

Effect of oral administration of sulfadiazine and trimethoprim in combination on thyroid function in dogs.

The effect of oral administration of sulfadiazine and trimethoprim in combination on serum concentrations of thyroxine (T4), triiodothyronine (T3) and free thyroxine (fT4) and the thyroid hormone response to thyrotropin administration was assessed. Six dogs were administered sulfadiazine (12.5 mg/kg) and trimethoprim (2.5 mg/kg) orally for 28 days; six untreated dogs acted as controls. Serum T4, T3 and fT4 were determined weekly during and for four weeks after treatment. Thyrotropin response tests were performed prior to treatment, after four weeks of treatment and three weeks after stopping treatment. There were no significant differences in mean serum T4, T3 or fT4 concentrations between treated and control groups at any time during the study. Mean concentration of serum T4 over time did not differ significantly from baseline concentration in either group. Significant differences in the mean serum T3 and fT4 concentrations occurred at several time points in treatment and control groups, and were apparently unrelated to treatment. Significant differences in the T4 or T3 response to thyrotropin administration within or between groups were not present. Serum T3 and fT4 concentrations fluctuate in normal dogs. Administration of sulfadiazine and trimethoprim in combination does not affect tests of thyroid function in the dog.

Administration, Oral↗

PubMed1990

Epizootiologic patterns of diabetes mellitus in cats: 333 cases (1980-1986).

Medical records from 333 cats with diabetes mellitus were studied retrospectively, using epidemiologic methods to determine the incidence of and risk factors for diabetes mellitus in this species. Abstracts were derived, using the Veterinary Medical Data Program with its 17 participating academic institutions in the United States and Canada. A reference population of 135,651 cats was derived from the same hospital population and time span (July 1980 to June 1986). The incidence of diabetes mellitus in cats was determined to be 2.45 cases/1,000 cat-years-of-risk during the 6-year study period. Breed had no detectable effect on risk for diabetes mellitus. In contrast, body weight, age, gender, and neutering had a significant (P less than or equal to 0.01) effect. Body weight of cats was categorized as being less than or greater than or equal to 6.8 kg. The higher body weight, probably indicating obesity, contributed a 2.2-fold increase in risk, even after adjustment for age and gender (adjusted odds ratio). The etiologic fraction for high body weight was 3.8%, suggesting that an estimated 3.8% of cases of diabetes mellitus was attributable to this factor alone. Over 50% of diabetic cats were greater than 10 years old, and the etiologic fraction for age greater than 7 years alone was 73.5%. Age was a significant (P less than 0.001) and the most important single risk factor for development of the disease in cats, with adjusted odds ratios of 8.3 and 14.4 for age 7 to 10 years and greater than 10 years, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗