Toxoplasma gondii-like organisms in skin aspirates from a cat with disseminated protozoal infection

An 8-year-old, male domestic shorthair cat was referred to the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania with a 3-day history of lethargy, inappetance, hyperemic skin nodules, coughing, and vomiting. Laboratory results included nonregenerative anemia, lymphopenia, thrombocytopenia, hypoalbuminemia, hyponatremia, and increased alanine aminotransferase and aspartate aminotransferase activities. Cytology of the skin nodules revealed many spindle- to crescent-shaped protozoal organisms, with morphology consistent with Toxoplasma gondii or Neospora caninum. Gross necropsy, histopathologic, immunohistochemical, and transmission electron microscopic findings confirmed a systemic protozoal infection; however, the organism exhibited characteristics of both N caninum and T gondii. Diagnosis of a T gondii-like infection was based on internal structures of the organism and positive reaction to rabbit polyclonal antibodies to T gondii. Reports of toxoplasmic dermatitis are rare in the cat and dog, and this is the first reported diagnosis of T gondii-like protozoa in skin aspirates.     

Correlation of rhinoscopic signs of inflammation with histologic findings in nasal biopsy specimens of cats with or without upper respiratory tract disease

OBJECTIVE: To investigate the correlation of cumulative rhinoscopic findings of hyperemia, mucus accumulation, and turbinate destruction with the type and severity of inflammatory infiltrates in nasal biopsy specimens of cats with or without upper respiratory tract disease. DESIGN: Prospective study. ANIMALS: Cats with (n = 11) and without (6) upper respiratory tract disease and cats with unknown medical histories (27). PROCEDURES; Lesions of hyperemia, mucus accumulation, and turbinate destruction detected rhinoscopically were each scored (scale, 0 [absent] to 3 [severe]), and a cumulative rhinoscopic score for each nasal cavity was calculated. Fifty biopsy specimens were examined histologically, and inflammatory infiltrates (lymphoplasmacytic or neutrophilic) were graded as absent, mild, moderate, or severe. Cumulative rhinoscopic scores and inflammation grades were compared for each specimen-cavity combination. RESULTS: In cats of known disease status, there was a positive but weak correlation between cumulative rhinoscopic scores and inflammation grades in biopsy specimens. In cats of unknown disease status, there was no similar correlation. Biopsy specimens with minimal inflammation were commonly obtained from nasal cavities with low rhinoscopic scores; specimens with moderate or severe inflammatory changes were frequently obtained from cavities that appeared normal rhinoscopically. Type of inflammatory infiltrates was not correlated with rhinoscopic signs of inflammation. CONCLUSIONS AND CLINICAL RELEVANCE: The correlation of rhinoscopic findings with inflammation severity in nasal biopsy specimens (determined histologically) was weak or lacking in cats of known and unknown disease status, respectively. Results indicated that rhinoscopy with biopsy provides more complete evaluation of nasal disease than rhinoscopy alone in cats.     

Differences in expression of retinal pigment epithelium mRNA between normal canines

A reference database of differences in mRNA expression in normal healthy canine retinal pigment epithelium (RPE) has been established. This database identifies non-informative differences in mRNA expression that can be used in screening canine RPE for mutations associated with clinical effects on vision. Complementary DNA (cDNA) pools were prepared from mRNA harvested from RPE, amplified by PCR, and used in a subtractive hybridization protocol (representational differential analysis) to identify differences in RPE mRNA expression between canines. The effect of relatedness of the test canines on the frequency of occurrence of differences was evaluated by using 2 unrelated canines for comparison with 2 female sibling canines of blue heeler/bull terrier lineage. Differentially expressed cDNA species were cloned, sequenced, and identified by comparison to public database entries. The most frequently observed differentially expressed sequence from the unrelated canine comparison was cDNA with 21 base pairs (bp) identical to the human epithelial membrane protein 1 gene (present in 8 of 20 clones). Different clones from the same-sex sibling RPE contained repetitions of several short sequence motifs including the human epithelial membrane protein 1 (4 of 25 clones). Other prevalent differences between sibling RPE included sequences similar to a chicken genetic marker sequence motif (5 of 25), and 6 clones with homology to porcine major histocompatibility loci. In addition to identifying several repetitively occurring, noninformative, differentially expressed RPE mRNA species, the findings confirm that fewer differences occurred between siblings, highlighting the importance of using closely related subjects in representational difference analysis studies.     

A comprehensive study of Easter lily poisoning in cats.

This study was conducted with 3 objectives in mind: first, to identify the toxic fraction (aqueous or organic) in leaves and flowers; second, to identify diagnostic marker(s) of toxicosis in cats; and, third, to evaluate the morphologic effects of intoxication. The study was conducted in 2 phases. Phase 1 was to identify which extract, organic or aqueous, was nephrotoxic and also to determine the appropriate dose for use in the phase 2 studies. Results indicated that only the aqueous extracts of leaves and flowers were nephrotoxic and pancreotoxic. To identify the proximate toxic compound, cats in the phase 2 study were orally exposed to subfractions of the aqueous flower extract, 1 subfraction per cat. Results confirmed vomiting, depression, polyuria, polydipsia, azotemia, glucosuria, proteinuria, and isosthenuria as toxic effects of the Easter lily plant. Another significant finding in serum was elevated creatinine kinase. Significant histologic kidney changes included acute necrosis of proximal convoluted tubules and degeneration of pancreatic acinar cells. Renal ultrastructural changes included swollen mitochondria, megamitochondria, edema, and lipidosis. Subfraction IIa3 of the aqueous floral extract contained most of the toxic compound(s). These studies reproduced the clinical disease, identified the most toxic fraction of the Easter lily, and helped characterize the clinical pathology, histopathology, and ultrastructural pathology associated with the disease.     

Herbicide loss following application to a roadside

Risk assessments for herbicides applied to roads are limited by the lack of knowledge on the fate and behaviour of the compounds in the urban environment. This study was designed to address this deficiency by quantifying the percentage loss of six herbicides following application to a roadside. Herbicides were applied on two occasions to a 16-m length of roadside and kerb edge. An automatic water sampler was used to collect run-off, draining to a single gulley pot, until 25 mm of rain had fallen. Samples were analysed for glyphosate, atrazine, diuron, oxadiazon and oryzalin, and peak concentrations were 650, 2210, 1810, 390 and 70 micrograms litre-1 respectively. Isoxaben was also applied, but concentrations in run-off were below the limit of detection (10 micrograms litre-1). Herbicide concentrations all followed a similar pattern of rapid decline throughout the first rain event following application, with the majority of loss occurring within the first 10 mm of accumulated rainfall, but compounds of high solubility and low Koc produced the highest peak concentrations. For those compounds of relatively low solubility and moderate Koc, application rate may be an influential factor in determining herbicide loss for these compounds. The percentage loss of the active substances applied differed between compounds, ranging from < 10% to 73%. The ecotoxicological significance of the results is discussed.     

Constitutive expression of a phenylalanine ammonia-lyase gene from Stylosanthes humilis in transgenic tobacco leads to enhanced disease resistance but impaired plant growth

Transgenic tobacco plants expressing a phenylalanine ammonia-lyase cDNA (ShPAL), isolated from Stylosanthes humilis, under the control of the 35S promoter of the cauliflower mosaic virus were produced to test the effect of high level PAL expression on disease resistance. The transgenic plants showed up to eight-fold PAL activity and were slowed in growth and flowering relative to non-transgenic controls which have segregated out the transgene. The expression of the ShPAL transgene and elevated PAL levels were correlated and stably inherited. In T₁ and T₂ tobacco plants with increased PAL activity, lesion expansion was significantly reduced by up to 55% on stems inoculated with the Oomycete pathogen Phytophthora parasitica pv. nicotianae. Lesion area was significantly reduced by up to 50% on leaves inoculated with the fungal pathogen Cercospora nicotianae. This study provides further evidence that PAL has a role in plant defence.     

Evaluation of a laparoscopic technique for collection of serial full-thickness small intestinal biopsy specimens in standing sedated horses

OBJECTIVE: To assess a technique for laparoscopic collection of serial full-thickness small intestinal biopsy specimens in horses. ANIMALS:13 healthy adult horses. PROCEDURES: In the ex vivo portion of the study, sections of duodenum and jejunum obtained from 6 horses immediately after euthanasia were divided into 3 segments. Each segment was randomly assigned to the control group, the double-layer hand-sewn closure group, or the endoscopic linear stapler (ELS) group. Bursting strength and bursting wall tension were measured and compared among groups; luminal diameter reduction at the biopsy site was compared between the biopsy groups. In the in vivo portion of the study, serial full-thickness small intestinal biopsy specimens were laparoscopically collected with an ELS from the descending duodenum and distal portion of the jejunum at monthly intervals in 7 sedated, standing horses. Biopsy specimens were evaluated for suitability for histologic examination. RESULTS: Mean bursting strength and bursting wall tension were significantly lower in the ELS group than in the hand-sewn and control groups in both the duodenal and jejunal segments. Use of the hand-sewn closure technique at the biopsy site reduced luminal diameter significantly more than use of the stapling technique. In the in vivo part of the study, all 52 biopsy specimens collected during 26 laparoscopic procedures were suitable for histologic examination and no clinically important perioperative complications developed. CONCLUSIONS AND CLINICAL RELEVANCE: Laparoscopic collection of serial full-thickness small intestinal biopsy specimens with a 45-mm ELS may be an effective and safe technique for use in healthy adult experimental horses.     

Role of bacteria in the pathogenesis of recurrent uveitis in horses from the southeastern United States

OBJECTIVE: To determine the role of intraocular bacteria in the pathogenesis of equine recurrent uveitis (ERU) in horses from the southeastern United States by evaluating affected eyes of horses with ERU for bacterial DNA and intraocular production of antibodies against Leptospira spp. SAMPLE POPULATION: Aqueous humor, vitreous humor, and serum samples of 24 clinically normal horses, 52 horses with ERU, and 17 horses with ocular inflammation not associated with ERU (ie, non-ERU inflammation). PROCEDURES: Ribosomal RNA quantitative PCR (real-time PCR) assay was used to detect bacterial DNA in aqueous humor and vitreous humor from clinically normal horses (n = 12) and horses with chronic (> 3-month) ERU (28). Aqueous humor and serum were also evaluated for anti-Leptospira antibody titers from clinically normal horses (n = 12), horses with non-ERU inflammation (17), and horses with confirmed chronic ERU (24). RESULTS: Bacterial DNA was not detected in aqueous humor or vitreous humor of horses with ERU or clinically normal horses. No significant difference was found in titers of anti-Leptospira antibodies in serum or aqueous humor among these 3 groups. Only 2 horses, 1 horse with ERU and 1 horse with non-ERU inflammation, had definitive intraocular production of antibodies against Leptospira organisms. CONCLUSIONS AND CLINICAL RELEVANCE: In horses from the southeastern United States, Leptospira organisms may have helped initiate ERU in some, but the continued presence of the organisms did not play a direct role in the pathogenesis of this recurrent disease.