Treatment of canine sinonasal aspergillosis with clotrimazole infusion in patients with cribriform plate lysis.

OBJECTIVE: To describe the treatment of sinonasal aspergillosis with topical 1% clotrimazole solution in dogs with cribriform plate lysis. MATERIALS AND METHODS: This retrospective study includes data retrieval from medical records of dogs with sinonasal aspergillosis and cribriform plate lysis that underwent topical treatment with 1% clotrimazole solution. RESULTS: Five dogs with sinonasal aspergillosis, cribriform plate lysis diagnosed on CT scans, and normal neurologic examinations were treated with a single (n=3) or multiple (n=2) infusions of clotrimazole solution. No dogs developed clinical neurologic disease after therapy. CLINICAL SIGNIFICANCE: In this study, a topical clotrimazole solution was not associated with adverse neurologic effects in neurologically normal dogs with sinonasal aspergillosis and cribriform plate lysis.

A cysteine protease inhibitor protects dogs from cardiac damage during infection by Trypanosoma cruzi.

Cruzain is an essential cysteine protease of Trypanosoma cruzi and a therapeutic target for Chagas' disease. Eight dogs were infected with T. cruzi; three were treated with an inhibitor of cruzain, K777, for 14 days. Treatment with K777 abrogated myocardial damage by T. cruzi, as documented by histopathological lesion scores and serum troponin I levels.

Effect of dietary protein on lean body wasting in dogs: correlation between loss of lean mass and markers of proteasome-dependent proteolysis.

To determine the effect of dietary protein intake on lean body wasting in adult canines a study was undertaken to investigate the Ubiquitin Proteasome (UP) pathway and concurrent changes in lean and fat body mass of canines fed variable sources and concentrations of dietary protein. Purpose-bred, intact female canines (56) between the ages of 2 and 3 years were fed either 12 or 28% protein diet for 10 weeks. Each diet contained variable amounts of corn gluten meal and chicken protein sources in ratios of 100 : 0, 67 : 33, 33 : 67 and 0 : 100 per cent (w/w), respectively. All diets were isocaloric with calories coming from protein : fat : carbohydrate at the respective ratios of 12 : 40 : 48% for the 12% diets, and 28 : 40 : 32% for the 28% diets. Standard dual energy X-ray absorptiometry was performed to assess total body lean and fat mass at weeks 0 and 10 of the dietary trial. Muscle biopsies were also taken and processed for protein determination and standard gel electrophoresis with subsequent Western blotting for 20S proteasome and PA700 regulatory cap subunit p31. Statistical analysis revealed a moderate degree of correlation between increasing quantities of corn gluten, which is low in essential amino acids (i.e. lysine, tryptophan), and increasing loss of lean body mass over the 10-week study (R = 0.56). Furthermore, a moderate degree of correlation was observed between increasing concentrations of corn gluten protein and decreased expression of the p31 subunit of the 26S proteasome (R = 0.49). Additionally, the dogs consuming the 12% protein diets had a significant increase in fat mass regardless of the protein source. These findings suggest that lean body wasting in adult canines can be associated with the consumption of low protein diets consisting of predominantly corn gluten, which is likely due to imbalances or subclinical deficiencies of specific essential amino acids, and that low protein diets may augment accumulation of adipose tissue. Although the mechanisms remain unclear, alteration of molecular targets of skeletal muscle proteolysis, specifically involving the UP pathway occur.

Upregulation of cardiac cell plasma membrane calcium pump in a canine model of Chagas disease.

We have previously demonstrated that cardiac myocytes isolated from the hearts of adult dogs develop rapid repetitive cytosolic Ca2+ transients, membrane depolarization, and cell contraction by mobilization of sarcoplasmic reticulum Ca2+ stores when exposed to a soluble factor from the trypomastigotes of Trypanosoma cruzi. These findings led us to investigate the regulatory mechanisms of cytosolic Ca2+ in cardiac tissues from dogs chronically infected with T. cruzi. Expression of the plasma membrane calcium pump (PMCA) RNA and protein was determined by Northern and Western blotting, respectively, followed by densitometric analyses. A 642-bp PMCA 1b complementary DNA probe derived from canine epicardial tissue hybridized to 2 major transcripts (7.3 and 5.3 kb) in canine epicardium. Expression of the dominant transcript (7.3 kb) was 77% greater in cardiac tissues obtained from dogs with chronic T. cruzi infection (140 days after inoculation) in comparison with constitutive expression levels in normal dogs. Monoclonal antibody 5F10, known to recognize all isoforms of the PMCA, was used to detect expression of the PMCA protein in epicardial tissue. Expression of a 142-kDa protein was increased by 58% in the cardiac tissues of infected dogs when compared with those from uninfected dogs. To establish a link between the upregulation of PMCA in dogs chronically infected with Chagas disease and the ventricular-based arrhythmias and myocardial failure that occur during this stage of disease both in dogs and humans, further study will be required.

Characterization of a serine protease activity in Sarcocystis neurona merozoites.

Sarcocystis neurona merozoites were examined for their ability to invade and divide in bovine turbinate (BT) cell cultures after treatment with cysteine (iodoacetamide), aspartic (pepstatin A), metallo-(1,10-phenanthroline and ethylene glycol-bis(aminoethylether)-tetraacetic acid [EGTA]), or serine (4-[2-aminoethyl]-benzenesulfonyl fluoride hydrochloride [AEBSF], phenylmethane sulphonyl fluoride [PMSF], and tosyl lysyl chloramethyl ketone [TLCK]) protease inhibitors. Significant (P < 0.01) inhibition of serine protease activity by PMSF and TLCK led to a reduction of 86 and 78% in merozoites produced in BT cell cultures, respectively, whereas AEBSF (1 mM) led to a 68% reduction in merozoites produced in BT cell cultures and a reduction of 84 and 92% at higher AEBSF concentrations (2 and 3 mM, respectively). Pepstatin A and iodoacetamide failed to cause any inhibition in merozoite production, whereas 1,10-phenanthroline and EGTA caused slight, but not significant, inhibition at 6 and 17%, respectively. In zymograms, 2 bands of protease activity between 65- and 70-kDa molecular weight were seen. The protease activity was inhibited by AEBSF but not by E-64 (cysteine protease inhibitor), EGTA, iodoacetamide, or pepstatin A. In native zymograms, the protease activity was highest between a pH range of 8 and 10. These data suggest that merozoites of S. neurona have serine protease activity with a relative molecular weight range between 65 and 70 kDa and optimal pH range between 8 and 10, which is essential for host cell entry at least in vitro. The protease activity described here could be a potential target for chemotherapy development.

Effect of carprofen on hemostatic variables in dogs.

OBJECTIVE: To evaluate the effect of carprofen on hemostatic variables in clinically normal dogs. ANIMALS: 12 clinically normal Labrador Retrievers. PROCEDURE: 10 dogs (6 females, 4 males) received carprofen (2.2 mg/kg of body weight, PO, q 12 h) for 5 days. Two dogs (untreated control group; 1 female, 1 male) did not receive carprofen. Hemostatic variables (platelet count, activated partial thromboplastin time, prothrombin time, fibrinogen, platelet aggregation, and bleeding time) were assessed for all dogs prior to treatment, on day 5 of treatment, and 2 and 7 days after discontinuation of the drug (days 7 and 12). Serum biochemical variables and Hct were assessed prior to treatment and on days 5 and 12. RESULTS: In dogs receiving carprofen, platelet aggregation was significantly decreased, and onset of aggregation was significantly delayed on days 5, 7, and 12, compared with pretreatment values. Activated partial thromboplastin time was significantly increased on days 5, 7, and 12 over pretreatment values in treated dogs, but values remained within reference ranges. Significant differences were not detected in buccal mucosal bleeding time, other serum biochemical and hemostatic variables, or Hct, compared with pretreatment values and the internal control group. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of carprofen for 5 days causes minor but not clinically important alterations in hemostatic and serum biochemical variables in clinically normal Labrador Retrievers. Carprofen is commonly used to treat osteoarthritis and chronic pain in dogs, but prior to this study, its effect on platelet aggregation and hemostatic variables was unknown.

Successful treatment of feline pancreatitis using an endoscopically placed gastrojejunostomy tube.

A cat with pancreatitis, diagnosed using abdominal ultrasonography, fine-needle aspirate cytopathology, and increased concentration of serum trypsin-like immunoreactive substance, was treated successfully using jejunal alimentation provided through a percutaneous gastrojejunostomy tube. This method of jejunal feeding is less technically difficult, less stressful for the patient, and has fewer complications than surgically placed jejunostomy tubes. Nutritional support with jejunal feeding is superior to total parenteral nutrition, as it maintains gut integrity, decreases septic complications, and may reduce exogenous insulin requirements. The methods of tube insertion and maintenance, and the physiological advantages over other feeding methods are described.

The analysis of group truncated binary data with random effects: injury severity in motor vehicle accidents.

The analysis of group truncated binary data has been previously considered by O'Neill and Barry (1995b, Biometrics 51, 533-541), where the analysis assumed that responses within each group were independent. In this paper, we consider the analysis of such data when there is group-level heterogeneity. A generalized linear mixed model is hypothesized to model the response and maximum likelihood estimates are derived for the truncated case. A score test is derived to test for heterogeneity. Finally, the method is applied to a set of traffic accident data.

Hematologic, hemostatic, and biochemical effects in cats receiving an oral chondroprotective agent for 30 days.

The objective of this study was to evaluate the effects of a chondroprotective agent on hematologic, hemostatic, and biochemical variables in clinically normal cats when administered at twice the recommended levels for 30 days. Fifteen clinically normal female domestic shorthaired cats were used. Twelve cats were given a chondroprotective agent orally, twice daily for 30 days. Three cats served as environmental controls and did not receive any treatment. The Wilcoxon's rank sum with a Bonferroni correction was used to evaluate the data statistically. Hematologic, hemostatic, and biochemical variables were assessed before treatment and on days 3, 14, and 30 of treatment. All cats remained healthy and showed no adverse reactions to treatment. No clinically and statistically significant shift outside a standard reference range was noted for any parameter. Hematocrit and red blood cell concentrations were decreased from pretreatment concentrations during days 3, 14, and 30 of treatment; however, these values were within a standard reference range at all time points. No significant changes were noted in platelet count, prothrombin time, or activated partial thromboplastin time. There were significant decreases in platelet aggregation response to high and low concentrations of collagen on day 3 and to the high concentration of collagen on days 14 and 30 compared with pretreatment values, but these values were not different from those of untreated cats. There was an increased time to response with the high concentration but not the low concentration of collagen on days 3, 14, and 30. Some parameters, such as potassium, anion gap, alkaline phosphatase, and bicarbonate, showed changes from pretreatment values at some but not all days of treatment. However, median concentrations remained within normal reference ranges, suggesting that these minor shifts were not indicative of clinical significance. Oral chondroprotective agents are widely prescribed in veterinary medicine for the treatment of degenerative joint disease. Safety studies have been performed in dogs; however, to date little is known about the safety of their use in cats. In this study, administration of this chondroprotective agent did not result in any clinically important change in hematologic, biochemical, and hemostatic variables when administered to healthy adult cats for 30 days at twice the recommended dosage.

Efficacy of a drug combination of praziquantel, pyrantel pamoate, and febantel against giardiasis in dogs.

OBJECTIVE: To evaluate efficacy of a combination of praziquantel, pyrantel pamoate, and febantel at 2 dosages for treating naturally acquired giardiasis in dogs. ANIMALS: 6 male and 9 female Beagles. PROCEDURE: Dogs were identified as naturally infected with Giardia sp, using the zinc sulfate concentration technique (ZSCT), and were allocated to 1 of 3 groups. Group-1 dogs were treated orally with a praziquantel (5.4 to 7 mg/kg of body weight), pyrantel pamoate (26.8 to 35.2 mg/kg), and febantel (26.8 to 35.2 mg/kg) combination, every 24 hours for 3 doses. Group-2 dogs were treated with the combination once. Group-3 dogs were nontreated controls. Four fecal samples were examined, using the ZSCT, from each dog of each group within 6 days of the last treatment. Dogs were considered to have giardiasis if 1 or more of the fecal samples had positive results for Giardia cysts. Dogs were examined daily for at least 10 days after the last treatment. RESULTS: Giardia cysts were not detected in the feces of any group-1 dog or in the feces of 2 of 5 group-2 dogs. Cysts were detected in the feces of 5 of 5 group-3 (nontreated control) dogs. Signs of toxicosis were not observed in any dog. CONCLUSION AND CLINICAL RELEVANCE: The current labeled dose (for treatment of various nematodes and cestodes, but not Giardia sp) of the combination given orally once reduces cyst excretion in Giardia-infected dogs, and should be considered for treatment of dogs shedding Giardia cysts, whether or not they have clinical signs of infection.

Naturally acquired leptospirosis in 36 dogs: serological and clinicopathological features.

Case records of 36 dogs with confirmed leptospirosis diagnosed at the New York State College of Veterinary Medicine from 1980 to 1995 were reviewed retrospectively, and clinical, serological and pathological findings were recorded to characterise the epidemiology of this disease in upstate New York. Titres were directed predominantly against serovars grippotyphosa and/or pomona in 31 of 34 dogs. Convalescent titres were measured for 53 per cent of dogs. The most common clinical presentation was acute renal failure. Increased liver enzyme activity was documented in 22 of 36 dogs. It is clear from this study that Leptospira pomona and grippotyphosa are important pathogens capable of causing severe renal and hepatic injury in dogs.

Effects of tromethamine buffer on coagulation variables and ionized calcium concentration in dogs.

OBJECTIVE: To evaluate coagulation variables in 2 groups of dogs after tromethamine administration. ANIMALS: 13 Beagles. PROCEDURES: Both groups of dogs received a 30-minute IV infusion of 10 ml of 0.3M tromethamine/kg of body weight. In unsedated dogs (group 1, n = 8), prothrombin time, activated partial thromboplastin time, normalized ionized calcium concentration, platelet numbers, and platelet function were measured prior to treatment, at the end of the infusion, and 1 hour after the infusion. In xylazine-sedated dogs (group 2, n = 5), buccal mucosal bleeding time and plasma percentage of von Willebrand factor antigen were measured before and 1 hour after infusion, and fibrin degradation products concentration was measured 1 hour after infusion. Platelet function was assessed by determining platelet aggregation and by measuring ATP release from the aggregating platelets over 6 minutes, using a whole blood aggregometer, with 20, 10, and 5 microM ADP and 5 and 10 micrograms of collagen/ml as platelet activation agonists. RESULTS: There was no significant change in any of the variables measured in either group of dogs, compared with baseline values. CONCLUSIONS AND CLINICAL RELEVANCE: When administered to healthy dogs, tromethamine does not change the coagulation indices measured.

Development of bone marrow toxicosis after albendazole administration in a dog and cat.

Bone marrow toxicosis was detected in a dog and cat following albendazole administration. Both animals were admitted with pancytopenia. In the dog, pancytopenia was attributed to severe panmarrow hypoplasia, whereas the cat had hypoplasia of erythroid and megakaryocytic series, but with a left-shifted granulocytic hyperplasia. Results of cytologic examination of bone marrow from both animals were compatible with acute injury. Both animals had been treated with albendazole for giardiasis prior to the onset of clinical signs. Bone marrow toxicosis was attributed to albendazole administration for the following reasons: this was the only or most recent drug administered, other causes of bone marrow toxicosis were not found, and both animals recovered rapidly with supportive care that consisted of fluid and antibiotic administration. Albendazole induced toxicosis appeared to be dose related in the dog and idiosyncratic in the cat. On the basis of the findings in this report, there is a potential for the development of albendazole induced bone marrow toxicosis in dogs and cats; therefore, veterinarians should exercise caution when using this drug.

Restoration of the transient outward potassium current by noradrenaline in chagasic canine epicardium.

1. The transient outward potassium current (Ito) is reduced in canine epicardial myocytes during the acute stage of infection with Trypanosoma cruzi (Chagas' disease). Sympathetic nerve terminals are also destroyed during the acute stage of this disease. To test whether the reduction of Ito is related to the absence of sympathetic innervation, acutely infected isolated epicardial myocytes were exposed in vitro to the sympathetic neurotransmitter noradrenaline (NA) and the effects of NA exposure on Ito were determined. 2. Continuous exposure to NA (1.0 microM) for 0-6 h had no effect on Ito density, whereas exposure to NA for 24 h significantly increased Ito density. Ito was also restored 24 h after a 1 h exposure to NA. Cell capacitance was not significantly affected by NA. 3. The alpha1-adrenergic receptor antagonist prazosin (0.1 microM) blocked the effects of NA on Ito, but the beta-adrenergic receptor antagonist propranolol (20 microM) did not. The beta-adrenergic receptor agonist isoprenaline (1 microM) had no effect on Ito. 4. Restoration of Ito by NA was prevented by pretreatment with neomycin (100 microM), a phospholipase C inhibitor, but not by pretreatment with 100-400 ng ml(-1) pertussis toxin (PTX). 5. The protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (0.1 microM) mimicked the effect of NA on Ito, whereas the inactive analogue 4alpha-phorbol (20 microM) had no effect on Ito. Pretreatment with bisindolylmaleimide (0.1 microM), a specific PKC inhibitor, completely blocked the effect of NA on Ito. 6. Thus, NA restores Ito in chagasic canine epicardial myocytes. The induction of Ito by NA appears to result from alpha1-adrenergic stimulation of PKC via a PTX-insensitive signalling cascade. These results suggest that the reduction of Ito in chagasic myocytes during the acute stage of Chagas' disease may reflect the lack of the trophic effects of sympathetic innervation.

Blastomycosis in six dogs in New York state.

Blastomycosis was diagnosed in 6 dogs living in New York state. To our knowledge, blastomycosis has not been previously reported in dogs in this area, and maps that indicate the prevalence of blastomycosis in North America often partially or completely exclude the state of New York. Environmental characteristics implicated in previous blastomycosis outbreaks in people can be found in New York state, and this may explain how these dogs became infected. Blastomycosis develops in people as well as in dogs, and an understanding of the ecologic and clinical features of blastomycosis can help veterinarians counsel their clients in matters of public health.

Hematologic, hemostatic, and biochemical effects in dogs receiving an oral chondroprotective agent for thirty days.

OBJECTIVE: To evaluate the effect of a chondroprotective agent on hematologic, hemostatic, and biochemical variables in clinically normal dogs when administered over 30 days. ANIMALS: 13 clinically normal Beagles of either sex. PROCEDURE: Hematologic and hemostatic variables were assessed prior to treatment and on days 3, 14, and 30 of treatment. Biochemical variables were assessed before treatment and on day 30 of treatment. RESULTS: Significant (P < 0.05) decreases were noted in hematocrit, hemoglobin, WBC, and segmented neutrophil variables on days 3 and 14 of treatment. A significant decrease in red distribution width was noted on days 3 and 30, in RBC count on day 3, and in lymphocyte numbers on day 30. There were also significant reductions of aggregation in response to adenosine diphosphate and collagen on days 14 and 30. Significant decreases were noted in total ATP release in response to collagen on days 14 and 30, as well as significant decrease in platelet count on days 14 and 30. No changes were noted in prothrombin time, activated partial thromboplastin time, mucosal bleeding time, or biochemical variables during the study. CONCLUSIONS: Administration of this chondroprotective agent causes minor but not clinically important changes in hematologic and hemostatic variables in young, clinically normal dogs. CLINICAL RELEVANCE: Oral chondroprotective agents are widely prescribed in veterinary medicine for the treatment of degenerative joint disease; however, to date, little is known about safety of their use.

A factor from Trypanosoma cruzi induces repetitive cytosolic free Ca2+ transients in isolated primary canine cardiac myocytes.

An unusual 120-kDa alkaline peptidase contained in a trypomastigote soluble fraction (TSF) of Trypanosoma cruzi is associated with the induction of repetitive Ca2+ transients and subsequent invasion by the parasite of a number of mammalian cell lines, including tissue culture L6E2 myoblasts (B. A. Burleigh and N. W. Andrews, J. Biol. Chem. 270:5172-5180, 1995; S. N. J. Moreno, J. Silva, A. E. Vercesi, and R. Docampo, J. Exp. Med. 180:1535-1540, 1994; A. Rodríguez, M. G. Rioult, A. Ora, and N. W. Andrews, J. Cell Biol. 129:1263-1273, 1995; I. Tardieux, M. H. Nathanson, and N. W. Andrews, J. Exp. Med. 179:1017-1022, 1994). Using single cell spectrofluorometry and whole-cell patch clamping, we show that TSF produces rapid repetitive cytosolic Ca2+ transients (each associated with cell contraction) in primary cardiac myocytes isolated from dogs. The response of myocytes to TSF was dose dependent in that increasing numbers of cells responded to increasing concentrations of TSF. The TSF-induced Ca2+ transients could be obliterated when TSF was heated or treated with trypsin or the protease inhibitor leupeptin. Aprotinin, pepstatin A, and E-64 did not affect TSF activity. The TSF-induced Ca2+ transients and trypomastigote cell invasion could not be inhibited by alpha (prazosin)- or beta (propanolol)-adrenergic blockers or L-type Ca2+ channel blockers (verapamil, nisoldipine, or cadmium) or by removal of extracellular Ca2+. However, inhibition of pertussis toxin-sensitive G proteins and Ca2+ release from the sarcoplasmic reticulum (with thapsigargin or ryanodine) prevented the TSF-induced Ca2+ transients and cell invasion by trypomastigotes. These data suggested that cardiac myocyte pertussis toxin-sensitive G proteins are associated with the regulation of TSF-induced Ca2+ transients and myocyte invasion by trypomastigotes but are independent of Ca2+ entry into the cytosol via L-type Ca2+ channels. The Ca2+ transients are dependent on release of Ca2+ from sarcoplasmic reticulum Ca2+ stores, but this release is not dependent on extracellular Ca2+ or on the classic model of Ca2+ -induced Ca2+ release in cardiac myocytes. Further, subthreshold depolarizations, together with cell contraction as demonstrated by whole-cell patch clamping, occurred with each Ca2+ transient. However, the depolarizations were of magnitude insufficient to generate an action potential, providing further evidence for a lack of dependence on L-type Ca2+ channels and other voltage-dependent channels (Na+ and K+ channels) in the generation of TSF-induced Ca2+ transients. Our findings suggest that primary canine cardiac myocytes respond to TSF and parasite invasion in ways similar to those of the in vitro cell lines studied to date. Since cardiac myocytes are primary targets for T. cruzi in the vertebrate host, our study indicates that TSF may play a role in the pathogenesis of Chagas' disease in humans.

Activity of lytic peptides against intracellular Trypanosoma cruzi amastigotes in vitro and parasitemias in mice.

Three cecropin-like lytic peptides (DC-1, DC-2, and DC-2R) were synthesized with virtually no sequence homology with the natural compound (cecropin B) while retaining the charge distribution, amphipathic, and hydrophobic properties of the natural compound. A fourth analog (alpha-Pi) without these later properties, but a similar molecular weight, was also synthesized as a nonlytic peptide control. The 3 lytic peptides were examined for their ability to kill Trypanosoma cruzi trypomastigotes in vitro, intracellular amastigotes in vitro, and their toxicity to a mammalian cell line. DC-2 at 5 microM and DC-1 and DC-2R at 10 microM were 100% effective in killing T. cruzi trypomastigotes in vitro, suggesting at least a 10-fold increase in lytic activity over previous tested lytic peptide analogues, SB-37 and Shiva-1. When T. cruzi-infected Vero cells were treated with a single or double exposure of low concentrations (2.5 microM) of DC-1, DC-2, and DC-2R there was a significant (P < 0.05) reduction in amastigote numbers/cell when compared to untreated and alpha-Pi-treated T. cruzi-infected cells. Vero cells alone treated with the lytic peptides showed no reduction in number or toxicity. One of the peptides (DC-1) was tested for its toxicity in AJ mice and its ability to reduce parasitemias in T. cruzi-infected AJ mice. No untoward effects were seen in AJ mice injected intravenously with 50 micrograms/mouse daily for 10 days. There was a significant (P < 0.05) reduction in parasitemia and mortality by day 14 postinoculation (from 100% to 0%) in T. cruzi-infected AJ mice given 25 micrograms of DC-1/mouse on days 2, 4, 6, 8, and 10 postinoculation.