Management and outcome of cats with ureteral calculi: 153 cases (1984-2002)

OBJECTIVE: To determine outcome of medical and surgical treatment in cats with ureteral calculi. DESIGN: Retrospective study. ANIMALS: 153 cats. PROCEDURE: Medical records were reviewed. Owners and referring veterinarians were contacted for follow-up information. RESULTS: All cats were initially treated medically before a decision was made to perform surgery. Medical treatment included parenteral administration of fluids and diuretics to promote urine production and passage of the ureteral calculus and supportive treatment for renal failure. Ureteral calculi in the proximal portion of the ureter were typically removed by ureterotomy, whereas ureteral calculi in the distal portion of the ureter were more likely to be removed by partial ureterectomy and ureteroneocystostomy. Ureterotomy could be performed without placement of a nephrostomy tube for postoperative urine diversion. Postoperative complication rate and perioperative mortality rate were 31% and 18%, respectively. The most common postoperative complications were urine leakage and persistent ureteral obstruction after surgery. Chronic renal failure was common at the time of diagnosis and continued after treatment, with serum creatinine concentration remaining greater than the upper reference limit in approximately half the cats. Twelve-month survival rates after medical and surgical treatment were 66% and 91%, respectively, with a number of cats dying of causes related to urinary tract disorders, including ureteral calculus recurrence and worsening of chronic renal failure. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that medical and surgical management of ureteral calculi in cats are associated with high morbidity and mortality rates. Treatment can stabilize renal function, although many surviving cats will continue to have impaired renal function.     

Surgical management of adrenal gland tumors with and without associated tumor thrombi in dogs: 40 cases (1994-2001)

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.     

Confounding of patch quality and matrix effects in herbivore movement studies

Although the landscape matrix is increasingly incorporated into spatial-ecological population studies, little consideration has been given to the likely possibility that patch quality is confounded with the composition of the matrix surrounding each patch. For example, the nutritional quality of host-plant patches to an herbivore may be highly correlated with matrix composition, consequently obfuscating the importance of the matrix itself to interpatch dispersal. From a literature survey of the effects of the matrix on herbivore movement among host-plant patches, we found that 55% of the studies (6/11) failed to experimentally or statistically isolate the effects of the matrix from potential patch-quality effects on dispersal. Most studies consisted of mark-recapture experiments in natural landscapes where patch equality was not controlled or manipulated. Of the few studies that evaluated the relationship between matrix composition and patch quality, all of them (3/3) found that these two landscape factors covaried. These data suggest that in most matrix studies, effects of the matrix on dispersal may be wholly, or in part, due to underlying differences in patch quality. This revised version was published online in May 2005 with corrections to the Cover Date. This revised version was published online in July 2006 with corrections to the Cover Date.     

Hematologic and plasma biochemical changes associated with fenbendazole administration in Hermann's tortoises (testudo hermanni).

Toxicosis associated with benzimidazole anthelmintics has been reported with increasing frequency in zoologic collections. Clinical signs, clinicopathologic abnormalities, and gross and histologic lesions are primarily the result of damage to the gastrointestinal and hematopoietic systems. Profound leukopenia, especially granulocytopenia, is the most common and severe clinicopathologic change associated with benzimidazole administration. Death usually occurs from overwhelming systemic bacterial and/or fungal infections secondary to severe immunosuppression. In this 125-day study, six male Hermann's tortoises (Testudo hermanni) were treated orally with two 5-day courses of fenbendazole 2 wk apart at a dosage of 50 mg/kg. Serial blood samples were used to assess hematologic and plasma biochemical changes before, during, and following the treatment period. Although the tortoises remained healthy, blood sampling indicated an extended heteropenia with transient hypoglycemia, hyperuricemia, hyperphosphatemia, and equivocal hyperproteinemia/hyperglobulinemia, which were considered to be in response to fenbendazole administration. Changes in several other clinicopathologic parameters appeared to correlate with fenbendazole administration. The hematologic and biochemical changes seen in the healthy animals in this study should be considered when treating compromised tortoises with fenbendazole. Hematologic and plasma biochemical status of tortoises/reptiles should be determined before treatment and monitored during the treatment period. The risk of mortality of an individual from nematode infection should be assessed relative to the potential for metabolic alteration and secondary septicemia following damage to hematopoietic and gastrointestinal systems by fenbendazole.     

Serum free thyroxine levels in cats maintained on diets relatively high or low in iodine

Excessive or deficient intake of iodine may play a role in the development of goitre and hyperthyroidism in cats. Previous investigations have shown that the serum free thyroxine level of cats is affected by brief administration of food high or low in iodine content. We have now measured serum free thyroxine levels in groups of cats fed relatively high or low iodine diets for much longer periods (5 months). In contrast to our earlier findings, the chronic ingestion of relatively high or low iodine diets did not lead to statistically significant differences in serum free thyroxine levels. The results of the present investigations show that the cat is able to maintain normal levels of thyroid hormone despite prolonged high or low iodine diets. It may be that the adaptive mechanisms that are called into play during chronic high or low iodine intake lead to thyroid disease, particularly in certain predisposed individuals.     

Enhancing catch-and-release science with biotelemetry

Catch‐and‐release (C&R) angling is widely practised by anglers and is a common fisheries management strategy or is a by‐product of harvest regulations. Accordingly, there is a growing body of research that examines not only the mortality associated with C&R, but also the sublethal physiological and behavioural consequences. Biotelemetry offers a powerful means of remotely monitoring the behaviour, physiology and mortality of fish caught and released in their natural environment, but we contend that its usefulness is still underappreciated by scholars and managers. In this study, we review the applications of biotelemetry in C&R science, identify novel research directions, opportunities and challenges. There are now about 250 C&R studies but only one quarter of these utilize biotelemetry. In fact, almost all of the C&R studies that have used biotelemetry have been conducted within the last decade. We found that the majority of C&R telemetry studies used either radio or acoustic telemetry, while comparatively few studies have used satellite technologies. Most C&R biotelemetry studies have been used to assess mortality rates, behavioural impairments or to evaluate the effects of displacement on fish. A small fraction of studies (<8%) have used physiological sensors despite the fact that these tools are highly applicable to understanding the multiple sublethal consequences of C&R and are useful for providing mechanistic insights into endpoints such as death. We conclude that C&R science has the potential to benefit greatly from biotelemetry technology, particularly with respect to providing more robust short‐term and delayed mortality estimates and adopting a more integrative and comparative approach to understanding the lethal and sublethal impacts of C&R. However, there are still a number of challenges including (i) the need for appropriate controls and methodological approaches, (ii) the need for accounting for tagging and handling stress and mortality, and (iii) the need for certainty in assessing mortality. However, the benefits associated with C&R biotelemetry outweigh its disadvantages and limitations and thereby offer C&R researchers a suite of new tools to enhance fisheries management and conservation.     

Effects of fragmentation on the seed predation and dispersal by rodents differ among species with different seed size

Fragmentation influences the population dynamics and community composition of vertebrate animals. Fragmentation effects on rodent species in forests may, in turn, affect seed predation and dispersal of many plant species. Previous studies have usually addressed this question by monitoring a single species, and their results are contradictory. Very few studies have discussed the fragmentation effect on rodent–seed interaction among tree species with different seed sizes, which can significantly influence rodent foraging preference and seed fate. Given that fruiting periods for many coexisting plant species overlap, the changing foraging preference of rodents may substantially alter plant communities. In this study, we monitored the dispersal and predation by rodents of 9600 seeds, belonging to 4 Fagaceae species with great variation in seed size, in both the edge and interior areas of 12 tropical forest fragments ranging in area from 6.3 to 13872.9 ha in Southwest China. The results showed that forest fragmentation altered the seed fates of all the species, but the intensity and even the direction of fragmentation effect differed between species with large versus small seeds. For the seeds harvested, fragment size showed negative effects in forest interiors but positive effects at edges for the 2 large‐seeded species, but showed little effect for the 2 small‐seeded species. For the seeds removed, negative effects of fragment size only existed among the small‐seeded species. The different fragmentation effect on seed dispersal and predation among plant species may, in turn, translate into the composition differences of the regeneration of the whole fragmented forest.     

Suspected myelodysplastic/myeloproliferative neoplasm in a feline leukemia virus‐negative cat

A 10‐year‐old castrated Domestic Short‐Haired cat was presented to a primary care veterinarian for a wellness examination and laboratory examination for monitoring of diabetes mellitus. The CBC revealed marked thrombocytosis, leukopenia and macrocytic, normochromic anemia. The cat tested negative for FeLV and feline immunodeficiency virus, but was positive for Mycoplasma haemominutum by PCR. Hematologic abnormalities were not responsive to therapy, so a repeat CBC and a bone marrow aspiration for cytology were performed. Additional blood smear findings included anisocytosis with megaloblastic erythroid precursors, large platelets, eosinophilic myelocytes and metamyelocytes, and rare unidentified blasts. The bone marrow smear was highly cellular, and the cytologic pattern was consistent with myelodysplastic syndrome with an erythroid predominance. At that time, 15% blasts were present. The cat was treated with a vitamin K₂ analog, doxycycline, and prednisolone, but without a clinical response. Within 3 months, euthanasia was elected due to declining quality of life, and a necropsy was performed. Postmortem bone marrow smears were highly cellular and dominated by monomorphic blasts of unknown line of origin (52%), persistent marked erythroid and megakaryocytic dysplasia, and ineffective erythropoiesis and granulopoiesis. Immunohistochemical, immunocytochemical, and cytochemical stains resulted in a diagnosis of acute myeloid leukemia of unclassified type. Additional histologic findings included mixed hepatitis with trematode infestation and lymphoplasmacytic interstitial nephritis with fibrosis. The marked thrombocytosis with myelodysplastic syndrome and the FeLV‐negative status of this cat were unusual. The difficulty in classifying the myelodysplasia and subsequent leukemia highlights a need for further reporting and characterization of these types of disease.