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Summary:

Of 48 privately-owned bitches evaluated 30 to 35 days after a single, unplanned breeding, 30 (62%) dogs were determined not to be pregnant by abdominal ultrasonography and 18 dogs were confirmed to be pregnant. Each pregnant dog was hospitalized, allotted to a treatment group, and given prostaglandin F_2α, sc, at 1 of 3 dosages: group 1, 0.1 mg/kg of body weight, every 8 hours; group 2, 0.25 mg/kg, every 12 hours; and group 3, 0.1 mg/kg, every 8 hours for 2 days and then 0.2 mg/kg every 8 hours thereafter. Plasma from each dog was assayed for progesterone concentration before treatment and daily until abortion was completed. Physical examinations and abdominal ultrasonography were performed every 12 and 48 hours, respectively. Treatment was continued until abortion was complete as determined by results of abdominal ultrasonography. Ultrasonography was performed earlier than the scheduled 48 hours if abdominal contractions, fetuses, or bloody or dark colored vaginal discharge was observed.

Dogs of 14 breeds were treated; body weight ranged from 5.4 to 37.7 kg. All dogs aborted all fetuses within 9 days of beginning treatment. Abdominal palpation was not satisfactory in confirming whether the abortion process had been completed; however, results of ultrasonography were a reliable indicator. Plasma progesterone concentrations prior to treatment were typical of the middle phase of gestation, with all concentrations > 6.0 ng/ml. The plasma progesterone concentration decreased significantly in each dog after the first 48 hours of therapy. None of the bitches aborted any fetal material until at least 24 hours after the plasma progesterone concentration was < 2.0 ng/ml. Side effects of the initial injection of prostaglandin F_2α included panting (n = 14), excess salivation (n = 13), vomiting (n = 12), defecation (n = 10), and urination (n = 3). Side effects were not life threatening, lasted < 30 minutes in all but 2 dogs, and were less severe with each subsequent treatment.

Prostaglandin F_2α provided a safe, reliable, effective, and practical abortifacient in pregnant bitches treated at 30 to 35 days after an unplanned breeding. The results of all 3 protocols were satisfactory.

SUMMARY

Serum glucose and immunoreactive insulin concentrations were monitored after topical administration of an insulin-containing ophthalmic solution in 20 clinically normal cats. Three ophthalmic surface-acting agents, benzalkonium chloride, dimethyl sulfoxide, and proparacaine hydrochloride, were evaluated individually for their effectiveness in enhancing absorption of topically applied insulin. The ophthalmic effects of insulin-containing ophthalmic preparations were assessed by complete ophthalmic examination before and at the conclusion of each test period. Withholding of food overnight (12 hours) preceded each topical application of insulin-containing ophthalmic solution (12.25 to 26.4 U/cat), either alone or in combination with surface-acting agents, after which blood samples were drawn serially from an indwelling iv catheter over a period of 8 hours. Baseline serum insulin concentration, after food was withheld for 12 hours, in nonstressed cats was 6.0 μU/ml (geometric mean), and an exponentiation of the logarithmic quantity (mean ± sd) yielded values of 1.5 to 23.0 μU/ml. All ophthalmic solutions tested failed to significantly lower serum glucose concentration or increase serum insulin concentration. Solutions used did not induce deleterious effect on ocular structures. Results indicate that topical administration of insulin-containing ophthalmic solution, either alone at the concentrations used or in combination with surfaceacting agents, did not result in effective absorption of insulin across the conjunctival and lacrimal nasal mucosa in biologically relevent quantities. Thus, this route of insulin administration, under these specific conditions, is not an effective alternative or adjunct to SC administration of insulin for treatment of cats with insulin-dependent diabetes mellitus or severe noninsulin-dependent diabetes mellitus.

Abstract

Objective—To evaluate adrenal sex hormone concentrations in response to ACTH stimulation in healthy dogs, dogs with adrenal tumors, and dogs with pituitary- dependent hyperadrenocorticism (PDH).

Design—Prospective study.

Animals—11 healthy control dogs, 9 dogs with adrenal-dependent hyperadrenocorticism (adenocarcinoma [ACA] or other tumor); 11 dogs with PDH, and 6 dogs with noncortisol-secreting adrenal tumors (ATs).

Procedure—Hyperadrenocorticism was diagnosed on the basis of clinical signs; physical examination findings; and results of ACTH stimulation test, low-dose dexamethasone suppression test, or both. Dogs with noncortisol-secreting ATs did not have hyperadrenocorticism but had ultrasonographic evidence of an AT. Concentrations of cortisol, androstenedione, estradiol, progesterone, testosterone, and 17-hydroxyprogesterone were measured before and 1 hour after IM administration of 0.25 mg of synthetic ACTH.

Results—All dogs with ACA, 10 dogs with PDH, and 4 dogs with ATs had 1 or more sex hormone concentrations greater than the reference range after ACTH stimulation. The absolute difference for progesterone, 17-hydroxyprogesterone, and testosterone concentrations (value obtained after ACTH administration minus value obtained before ACTH administration) was significantly greater for dogs with ACA, compared with the other 3 groups. The absolute difference for androstenedione was significantly greater for dogs with ACA, compared with dogs with AT and healthy control dogs.

Conclusions and Clinical Relevance—Dogs with ACA secrete increased concentrations of adrenal sex hormones, compared with dogs with PDH, noncortisol-secreting ATs, and healthy dogs. Dogs with noncortisol-secreting ATs also have increased concentrations of sex hormones. There is great interdog variability in sex hormone concentrations in dogs with ACA after stimulation with ACTH. (J Am Vet Med Assoc 2005;226:556–561)

Abstract

Objective—To compare incidence of diabetes mellitus in cats that had undergone renal transplantation with incidence in cats with chronic renal failure, compare mortality rates in cats that underwent renal transplantation and did or did not develop diabetes mellitus, and identify potential risk factors for development of posttransplantation diabetes mellitus (PTDM) in cats.

Design—Retrospective case series.

Animals—187 cats that underwent renal transplantation.

Procedures—Medical records were reviewed.

Results—26 of the 187 (13.9%) cats developed PTDM, with the incidence of PTDM being 66 cases/1,000 cat years at risk. By contrast, the incidence of diabetes mellitus among a comparison population of 178 cats with chronic renal failure that did not undergo renal transplantation was 17.9 cases/1,000 cat years at risk, and cats that underwent renal trans-plantation were 5.45 times as likely to develop diabetes mellitus as were control cats with chronic renal failure. The mortality rate among cats with PTDM was 2.38 times the rate among cats that underwent renal transplantation but did not develop PTDM. Age, sex, body weight, and percentage change in body weight were not found to be significantly associ-ated with development of PTDM.

Conclusions and Clinical Relevance—Results suggest that cats that undergo renal transplantation have an increased risk of developing diabetes mellitus, compared with cats with chronic renal failure, and that mortality rate is higher for cats that develop PTDM than for cats that do not.

Abstract

Objective—To describe the clinicopathologic features of a cohort of dogs with adrenocortical masses that underwent laparoscopic adrenalectomy and to compare perioperative morbidity and mortality rates in these dogs with rates for dogs that underwent open adrenalectomy for resection of similarly sized (maximal diameter, ≤ 5 cm) adrenocortical masses.

Design—Retrospective case series.

Animals—48 client-owned dogs that underwent laparoscopic (n = 23) or open (25) adrenalectomy for noninvasive tumors (ie, tumors that did not invade the vena cava or other surrounding organs).

Procedures—Medical records were reviewed. History, clinical signs, physical examination findings, clinicopathologic findings, imaging results, and surgical variables were recorded. A 3- or 4-port approach was used for laparoscopic adrenalectomy. Surgical time, perioperative complications, postoperative and overall hospitalization times, and perioperative deaths were recorded and compared between groups.

Results—The surgical method for 1 dog was converted from a laparoscopic to an open approach. Perioperative death occurred in no dogs in the laparoscopic group and 2 dogs in the open adrenalectomy group. Surgical time was shorter for laparoscopic (median, 90 minutes; range, 40 to 150 minutes) than for open (median, 120 minutes; range, 75 to 195 minutes) adrenalectomy. Laparoscopic adrenalectomy was associated with shorter hospitalization time and more rapid discharge from the hospital after surgery, compared with the open procedure.

Conclusions and Clinical Relevance—With careful patient selection, laparoscopic adrenalectomy was associated with a low complication rate and low conversion rate for resection of adrenocortical masses as well as shorter surgical and hospitalization times, compared with open adrenalectomy.

• The most common cause of naturally developing acromegaly in cats is a growth hormone-secreting adenoma of the pituitary pars distalis somatotropic cells.

• Irradiation of pituitary gland tumors in cats with acromegaly may result in transient or long-term resolution of acromegaly and diabetes mellitus.

• Diabetic cats with acromegaly may have a history of weight loss instead of weight gain.

Summary

Magnetic resonance imaging was used to determine the prevalence of visible pituitary masses in 21 dogs with recently diagnosed and untreated pituitary-dependent hyperadrenocorticism. All dogs had clinical signs and routine database values (CBC, serum biochemical panel, and urinalysis) consistent with a diagnosis of hyperadrenocorticism, and none had clinical signs suggestive of an intracranial mass. Each dog had plasma cortisol concentrations after adrenocorticotropic hormone administration or low-dose dexamethasone administration consistent with hyperadrenocorticism. Pituitary-dependent hyperadrenocorticism was confirmed by the finding of 2 equal-size adrenal glands on abdominal ultrasonography and by results of plasma endogenous adrenocorticotropic hormone concentration and high-dose dexamethasone suppression testing. Sagittal and transverse Tl-weighted magnetic resonance images of the brain were obtained before and after IV administration of gadopentenate dimeglumine.

Eleven dogs had visible masses, ranging in size from 4 to 12 mm at greatest vertical height. Mean age and body weight of dogs with a visible pituitary mass was not significantly different from dogs without a visible mass. There was no significant difference in endocrine test results when comparing dogs with a visible pituitary mass to dogs without. The prevalence of visible pituitary masses in dogs with pituitary-dependent hyperadrenocorticism was greater than suggested by the prevalence of clinical neurologic signs.

Abstract

Objective—To determine concentrations of 17α-hydroxyprogesterone (17OHP) in serum of healthy bitches during various stages of the reproductive cycle and in bitches with hyperadrenocorticism and to compare the dynamics of 17OHP with those of progesterone.

Design—Prospective evaluation study.

Animals—15 healthy sexually intact bitches and 28 spayed bitches with hyperadrenocorticism.

Procedures—11 healthy bitches were evaluated during estrus, nonpregnant diestrus, and anestrus (group 1); 4 other healthy bitches were evaluated during pregnancy and after ovariohysterectomy (group 2). Cycle stages were determined via physical examination, vaginal cytologic evaluation, and serum progesterone concentration. Bitches with hyperadrenocorticism were evaluated once at the time of diagnosis (group 3). Serum hormone concentrations were determined with immunoassays.

Results—In group 1, the serum 17OHP concentration was significantly higher in diestrus (median, 1.8 ng/mL) than in estrus (median, 1.1 ng/mL) and anestrus (median, 0.2 ng/mL) and higher in estrus than in anestrus. Changes in serum progesterone concentrations accounted for 22% (estrus) or 23% (diestrus) of the variation in serum 17OHP concentrations. In group 2, 17OHP and progesterone concentrations were significantly higher during pregnancy than after ovariohysterectomy. The serum 17OHP concentration in group 3 was significantly lower (median, 0.2 ng/mL) than in group 1 in estrus and diestrus and in group 2 during pregnancy (median, 0.7 ng/mL) but was not different from 17OHP concentrations in anestrus or after ovariohysterectomy (median, 0.2 ng/mL).

Conclusions and Clinical Relevance—Serum 17OHP concentrations in healthy bitches increased during estrus, diestrus, and pregnancy and at those times were higher than in spayed bitches with hyperadrenocorticism.

Abstract

Objective—To evaluate effects of dietary insoluble fiber on control of glycemia in cats with naturally acquired diabetes mellitus.

Design—Randomized controlled crossover trial.

Animals—16 cats with naturally acquired diabetes mellitus.

Procedure—Cats were fed a diet high in insoluble fiber (HF) containing 12% cellulose (dry-matter basis) or a diet low in insoluble fiber (LF) for 24 weeks; they were fed the other diet for the subsequent 24 weeks. Caloric intake and insulin treatment were adjusted to maintain stable body weight and control of glycemia, respectively. Cats were allowed an adaption period of 6 weeks after initiation of a diet, after which control of glycemia was evaluated at 6-week intervals for 18 weeks. Variables assessed included serum glucose concentration measured during the preprandial state, blood glycated hemoglobin concentration, serum glucose concentration measured at 2-hour intervals for 12 hours beginning at the time of the morning insulin injection, 12-hour mean serum glucose concentration, and mean fluctuation in serum glucose concentration from the 12-hour mean serum glucose concentration.

Results—Mean daily caloric intake, body weight, or daily insulin dosage did not differ significantly between cats when fed HF and LF diets. Mean preprandial serum glucose concentration, most postprandial serum glucose concentrations, and the 12-hour mean serum glucose concentration were significantly lower when cats consumed the HF diet, compared with values when cats consumed the LF diet.

Conclusions and Clinical Relevance—These results support feeding a commercially available diet containing approximately 12% insoluble fiber (dry-matter basis) to cats with naturally acquired diabetes mellitus. (J Am Vet Med Assoc 2000;216:1082–1088)

Abstract

Objective—To compare pathologic findings and results of adrenalectomy for adrenal gland tumors in dogs with and without vena caval tumor thrombi.

Design—Retrospective study.

Animals—40 dogs with adrenal gland tumors.

Procedure—Medical records were examined. An exact logistic regression analysis was used to evaluate associations between tumor type or right-sided versus left-sided tumor involvement and development of caval tumor thrombi and associations between tumor thrombi, tumor type, or right- versus left-sided location and perioperative complications and mortality rate. Survival was compared between dogs with and without tumor thrombi.

Results—Caval thrombi were detected in 25% of dogs, including 3 of 28 (11%) dogs with an adrenocortical tumor and 6 of 11 dogs with a pheochromocytoma. A caval tumor thrombus was detected in 6 of 17 right-sided and 4 of 20 left-sided tumors. Sensitivity and specificity of abdominal ultrasonography for detection of caval thrombi were 80 and 90%, respectively. Intraoperative and postoperative complications developed in 15 and 51% of dogs, respectively. The mortality rate was 22%. There were no significant differences in perioperative morbidity and mortality rates between dogs with and without tumor thrombi.

Conclusions and Clinical Relevance—Caval thrombi associated with adrenal gland tumors are amenable to adrenalectomy and thrombectomy without significantly increased perioperative morbidity and mortality rates, assuming the surgeon is experienced in appropriate techniques. (J Am Vet Med Assoc 2003;223: 654–662)