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Biomedical subjects

D B Church

Publications and source records attributed to D B Church.

At least 37 records · Page 2Linked to original sources
PubMed1998

Plasma cortisol responses to three corticotrophic preparations in normal dogs.

OBJECTIVE: To compare cortisol responses to three corticotrophic preparations in normal dogs. ANIMALS: Eight clinically normal dogs (four intact males, four intact females) of medium size. PROCEDURES: Each dog received four treatments on four separate occasions in a duplicated Latin square pattern. Treatments were two adrenocorticotrophin (ACTH) preparations given intramuscularly at 2.2 U/kg, one of the ACTH preparations given intramuscularly at 1 U/kg and a synthetic polypeptide with ACTH-like activity (tetracosactrin, cosyntropin) given intravenously at 5 micrograms/kg. Plasma samples were taken for cortisol assay before and at 0.5, 1, 2 and 4 h after treatment. RESULTS: Plasma cortisol concentrations were similar with the two ACTH preparations and at both dose rates. Tetracosactrin produced smaller mean peak cortisol concentrations, which tended to occur earlier than with ACTH, and smaller values for the area under the curve of plasma cortisol concentration from zero time to 4 h. CONCLUSION: The findings suggest that canine adrenal function can be tested adequately by giving ACTH intramuscularly at 1 U/kg and measuring plasma cortisol in samples taken at 0 and 2 h, or by giving tetracosactrin intravenously at 5 micrograms/kg and determining cortisol concentration at 0 and 1 h.

Adrenal Cortex Function Tests↗
PubMed1998

Effects of delmadinone acetate on pituitary-adrenal function, glucose tolerance and growth hormone in male dogs.

OBJECTIVE: To characterise the effects of delmadinone acetate on the pituitary-adrenal axis, glucose tolerance and growth hormone concentration in normal male dogs and dogs with benign prostatic hyperplasia. DESIGN: A prospective study involving nine normal male dogs and seven with prostatic hyperplasia. PROCEDURE: Delmadinone acetate was administered to six normal male dogs and seven dogs with benign prostatic hyperplasia at recommended dose rates (1.5 mg/kg subcutaneously at 0, 1 and 4 weeks). Three normal controls received saline at the same intervals. Blood concentrations of ACTH, cortisol, glucose, insulin and growth hormone were measured over 50 days. Intravenous glucose tolerance and ACTH response tests were performed before and after treatment in the nine normal animals. RESULTS: A substantial suppression of basal and 2 h post-ACTH plasma cortisol secretion was demonstrated after one dose in all dogs given delmadinone acetate. Individual responses after the second and third administration varied between recovery in adrenal responsiveness to continued suppression. Plasma ACTH concentration was also diminished after one treatment. No effects were evident on glucose tolerance or serum growth hormone concentrations. CONCLUSION: Delmadinone acetate causes adrenal suppression from inhibition of release of ACTH from the pituitary gland. Treated dogs may be at risk of developing signs of glucocorticoid insufficiency if subjected to stressful events during or after therapy. Neither glucose intolerance nor hypersomatotropism seems likely in male dogs given delmadinone acetate at the recommended dose rate, but the potential for excessive growth hormone secretion in treated bitches remains undetermined.

Adrenal Cortex↗
PubMed1998

Myotonia associated with hyperadrenocorticism in two dogs.

Two dogs developed a disabling gait abnormality characterised by stiffness. The abnormality was consistent with a diagnosis of myotonia secondary to hyperadrenocorticism. The first dog had iatrogenic hyperadrenocorticism, and its signs improved substantially after corticosteroid administration was gradually withdrawn. The second had pituitary-dependent hyperadrenocorticism, but myotonic signs progressed despite effective mitotane therapy. Procainamide administration reduced the myotonic stiffness in the second case.

Adrenocortical Hyperfunction↗
PubMed1997

Excision of a locally invasive thymoma causing cranial vena caval syndrome in a dog.

A 9-year-old female Golden Retriever was examined because of inappetance, labored breathing, edema, and distension of the veins of the neck. Thoracic radiography revealed pleural effusion and a cranial mediastinal mass. Biopsy results obtained by use of fine-needle aspiration were consistent with thymoma. At surgery, the tumor was found to have invaded the cranial vena cava. Extra- and intravascular portions were removed without complications, and the dog's clinical signs resolved. To our knowledge, this is the first documented report of an invasive thymoma causing cranial vena caval syndrome that has been successfully treated in a dog. In this instance, the simplest surgical method, namely venotomy and tumor extraction using venous inflow occlusion, was successful, obviating the need for temporary or permanent vascular conduits or grafts. These findings indicate that there is potential for surgical correction of invasive thymoma with cranial vena caval syndrome in some animals, and the prognosis is not always poor.

Animals↗
PubMed1997

Benign cranial mediastinal lesions in three cats.

Cranial mediastinal lesions were detected in three cats, associated with respiratory impairment (case one), spontaneous pneumothorax (case two) and myasthenia gravis (case three), respectively. On gross and histological examination, the first case was considered either a lymphangioma or a branchial cystic mass of the thymic region of the mediastinum; a cystic lesion was suggested by sonographic detection of multiple anechoic cavitations within a circumscribed mass, while fine needle aspiration cytology excluded lymphosarcoma. The second case was diagnosed histologically as a cystic thymoma, but the third case was not examined microscopically. The masses were amenable to surgical excision in the first two cats, while this proved unnecessary in the third case because of resolution following treatment with dexamethasone. Corticosteroid responsiveness was unhelpful in distinguishing between these benign lesions and lymphosarcoma, as in two cases there was a partial or complete response to dosing with prednisolone or dexamethasone. These cases are presented to emphasise that conditions other than lymphosarcoma can produce cranial mediastinal lesions in cats, and that the prognosis for surgical treatment of lymphangiomas, multilocular thymic cysts and cystic thymomas can be excellent.

Animals↗
PubMed1997

Nasopharyngeal cryptococcosis.

Naturally occurring cryptococcosis in five cats, a dog and a koala is described. Involvement of the nasopharynx was documented in all patients, and nasopharyngeal mass lesions accounted for the major presenting complaints in four. Signs referable to nasopharyngeal disease included snoring, stertor, inspiratory dyspnoea and aerophagia. Diagnoses were made by caudal rhinoscopy using a retroverted flexible endoscope, vigorous orthograde flushing with saline, or at necropsy. Concurrent cryptococcal rhinitis was present in all cases, although involvement appeared limited to the caudal nasal cavity in most cases. Typical signs of nasal cavity disease, such as sneezing and nasal discharge, were often absent. Treatment of nasopharyngeal cryptococcosis should include physical dislodgement or debulking of lesion(s) to provide immediate alleviation of upper airway obstruction, followed by systemic antifungal therapy to eliminate residual infection from the nasal cavity. Infections caused by Cryptococcus neoformans var gattii accounted for a disproportionately large number of these cases.

Animals↗
PubMed1996

Use of anti-inflammatory and analgesic drugs in dogs and cats.

Responses (486) were collared from a survey of 5054 Australian veterinarians on their use of anti-inflammatory and analgesic drugs in dogs and cats. Almost all respondents used glucocorticoids (usually prednisolone) to treat allergic, pruritic dermatoses in dogs, while two-thirds also gave fatty acid supplements and one-half used antihistamines. Almost 60% of respondents initially injected a glucocorticoid (frequently a long-acting preparation) when treating inflammatory skin diseases in dogs. More than 90% of respondents used glucocorticoids to treat immune-mediated haemolytic anaemia or thrombocytopenia, and about one-third also gave cytotoxic drugs. Administration of prednisolone on alternate days was generally favoured for long-term enteral steroid therapy. Phenylbutazone was the most preferred treatment for painful or inflammatory musculoskeletal disorders of dogs, but aspirin and pentosan polysulphate were also used widely. Regarding the use of analgesics drugs generally, both narcotic analgesics and non-steroidal anti-inflammatory drugs (NSAIDs) were used more widely in dogs than in cats, but alpha-2 agonists were used similarly in both species. The most commonly used narcotic analgesics were pethidine and buprenorphine in both species, while the NSAIDs used most often were flunixin and dipyrone in dogs and ketoprofen in cats. More than 80% of respondents generally used analgesic drugs with potentially painful surgical procedures, with doses given usually before anaesthetic recovery. Analgesic use rates varied with the condition, ranging from 94% for patients with acute severe trauma, through 60% for cruciate ligament repair and 29% for perineal herniorrahphy, to about 5% for ovariohysterectomy and dog castration. The three clinical signs most frequently nominated as indicators of pain in dogs and cats were (in descending order) vocalisation, response to handling or palpating the affected area, and mental depression. Other items mentioned frequently were behavioural changes and immobility (in both species), inappetence/anorexia in cats, and altered respiration in dogs.

Anemia, Hemolytic↗
PubMed1995

Effect of ingesta and of tablets of different strengths on the systemic availability of digoxin in normal dogs.

The plasma concentrations of digoxin were measured in eight normal dogs given digoxin on four occasions, using three different feeding regimens and tablets of two strengths. Although ingesta tended to slow the absorption of digoxin, the systemic availability of the drug, based on measurements of Cmax, tmax and AUC did not differ when digoxin tablets were given with canned food, with dry food, or without food. However, some of the pharmacokinetic characteristics and smaller individual variations with the dry food regimen would be considered advantageous for maintenance therapy. Tablets containing 62.5 micrograms or 250 micrograms of digoxin had a similar relative bioavailability. The peak plasma digoxin concentrations were higher in female dogs, and the trends in other data also suggested that the systemic availability of digoxin was better in female dogs.

Animals↗
PubMed1995

Preferences of veterinarians for drugs to treat heart disease in dogs and cats.

Responses (473) were collated from a questionnaire sent to 5054 veterinarians in Australia enquiring about drug preferences for treating cardiac disease in dogs and cats. When treating a small breed dog with endocardiosis and mild left congestive heart failure, 74% of 472 respondents used a diuretic, 67% a theophylline derivative, 27% a vasodilator and 20% a positive inotrope. Frusemide was the preferred diuretic and digoxin the preferred inotrope, but vasodilator use varied. Low sodium diets were "often recommended" by 71% of respondents. Propranolol was preferred to diltiazem for treating feline hypertrophic cardiomyopathy. Digoxin was clearly preferred for treating supraventricular dysrhythmias, while lignocaine and digoxin were preferred equally for ventricular dysrhythmias. Respondents appeared more willing than US veterinarians to use theophylline derivatives and prasozin, and less inclined to employ nitrates, hydralazine, inotropes other than digoxin, and low sodium diets.

Animals↗
PubMed1995

Effect of enalapril in dogs with pacing-induced heart failure.

A repeated-measures study was conducted on 5 dogs to clinically, radiographically, and echocardiographically characterize the actions of the angiotensin-converting enzyme inhibitor, enalapril, before and after development of experimentally induced heart failure. Heart failure was artificially induced, using a surgically implanted programmable ventricular pacemaker, which stimulated the heart at a rate of 245 beats/min until a low-output cardiomyopathic state developed. This condition was then stabilized by decreasing the pacing rate to 190 beats/min. Pacing-induced heart failure was successfully induced in a mean +/- SD 4.2 +/- 1.95 weeks. The condition closely resembled the clinical, radiographic, and echocardiographic features of naturally acquired idiopathic dilated cardiomyopathy in dogs. Enalapril was well tolerated by dogs, and clinical adverse reactions did not develop. Results of echocardiographic studies indicated that enalapril treatment during the control period resulted in a significant (P < 0.05) increase in velocity of circumferential fiber shortening and a significant (P < 0.05) decrease in left ventricular ejection time. Therapeutic responses to enalapril were evident after development of heart failure. These included reduced severity of clinical signs of disease, evidence of decreased radiographically determined cardiac size (2 of 5 dogs), radiographic evidence of a reduction in pulmonary edema and congestion (4 of 5 dogs), significant (P < 0.05) reductions in left atrial and ventricular chamber dimensions (left atrial dimension, diastolic left ventricular internal dimension as determined echocardiographically), and improvement in some echocardiographic indices of left ventricular performance (velocity of circumferential fiber shortening and left ventricular ejection time).

Analysis of Variance↗
PubMed1994

Effects of proligestone and megestrol on plasma adrenocorticotrophic hormone, insulin and insulin-like growth factor-1 concentrations in cats.

This paper reports changes in adrenocorticotrophic hormone (ACTH), insulin and insulin-like growth factor-1 (IGF-1) concentrations in cats from a previously published study. The cats were given oral megestrol acetate (MA, 5 mg once daily for 14 days), subcutaneous proligestone (PRG, 100 mg on two occasions one week apart) or subcutaneous saline (1 ml as for PRG). In the cats given saline (n = 6), basal ACTH, insulin and IGF-1 did not change significantly throughout the following seven weeks. The cats given MA (n = 7) developed significant suppression of plasma ACTH concentrations and hyperinsulinaemia during treatment and for two to four weeks after MA dosage ceased. In the cats given PRG (n = 7), plasma ACTH concentrations were not significantly altered although three cats had markedly suppressed values for some time after PRG treatment had ceased. Serum insulin concentrations were not significantly altered in the PRG-treated cats. The results suggest PRG may be a preferable alternative to MA in some situations.

Adrenocorticotropic Hormone↗
PubMed1994

Effect of chronic hypocortisolaemia on plasma cortisol concentrations during intravenous infusions of hydrocortisone sodium succinate in dogs.

Intravenous infusions of hydrocortisone sodium succinate (HSS) were given at 0.625 mg kg-1 hour-1 and 0.312 mg kg-1 hour-1 to six dogs. Plasma cortisol concentrations were measured by radioimmunoassay at 0, 15, 30, 45 and 60 minutes and then every 30 minutes for a further five hours. Chronic hypocortisolaemia was induced and maintained with mitotane and the HSS infusions were repeated after 31 and 50 days. No statistically significant difference was observed in the plasma cortisol concentrations after either period of hypocortisolaemia, but the plasma cortisol concentrations tended to be higher in most of the dogs.

Animals↗
PubMed1994

Effect of non-adrenal illness, anaesthesia and surgery on plasma cortisol concentrations in dogs.

Basal plasma cortisol concentrations in 25 dogs with non-adrenal illness were two to three times higher than in 25 normal dogs (158 +/- 25 nmol litre-1 compared with 65 +/- 22; mean +/- SD). In addition, plasma cortisol concentrations were measured in 12 animals undergoing major abdominal, thoracic or orthopaedic surgery and compared to a group of six anaesthetised dogs. Anaesthesia alone failed to significantly alter plasma cortisol levels, however, all forms of surgery produced a significant increase in plasma cortisol concentration which returned to normal 24 hours after completion of surgery.

Anesthesia, General↗
PubMed1993

Plasma cortisol concentrations in dogs given cortisone or placebo by mouth.

Fasted normal dogs (n = 8) were given fixed doses of cortisone acetate orally as 5 mg and 25 mg tablets; plasma cortisol concentrations were determined, and Cmax, tmax and area under the curve of plasma cortisol concentration plotted against time from zero to 12 hours were compared for the two preparations. In addition, these variables were compared when 25 mg tablets were administered with and without food. No significant difference in cortisol availability was noted for the two preparations and feeding did not apparently affect cortisone absorption. The findings in two hypoadrenocorticoid dogs were similar. Plasma cortisol concentrations in placebo-treated dogs similarly sampled showed minor fluctuations and were generally within accepted reference limits for normal dogs.

Absorption↗
PubMed1993

Treatment of feline hyperthyroidism using orally administered radioiodine: a study of 40 consecutive cases.

Forty cats with hyperthyroidism were treated using 200 to 300 (typically 250) MBq [corrected] of orally administered 131I. Thirty-six cases (90%) were successfully treated, as assessed by resolution of clinical signs and reduction in plasma thyroxine concentrations to normal or reduced values after treatment. Although higher doses of 131I appear to be required when the radioisotope is administered orally rather than intravenously, a less stressful administration procedure and greater availability of therapy capsules offer useful advantages for treating thyrotoxic cats.

Administration, Oral↗