Reticulocytosis in non-anaemic cats and dogs

OBJECTIVE

To evaluate the proportion of blood samples diagnosed with reticulocytosis without anaemia in cats and dogs and report the aetiology and mortality rate of affected animals.

MATERIALS AND METHODS

Retrospective multicentre study including haematological examination of 3956 cats and 11,087 dogs admitted to seven German veterinary clinics (2012 to 2014). The proportion of blood samples with reticulocytosis without anaemia was calculated, and after exclusion of multiple measurements of the same animal, clinical data were evaluated. Animals with reticulocytosis without anaemia were classified as healthy or diseased, and diseased patients were assigned to 12 disease groups. Pretreatment (i.e. non-steroidal anti-inflammatory drugs, glucocorticoids, dipyrone) was recorded.

RESULTS

The proportion of blood samples with reticulocytosis without anaemia was 3·1% (124/3956) in cats and 4·4% (492/11,087) in dogs. Overall, 1·8% (2/111) of cats and 1·5% (7/458) of dogs with reticulocytosis without anaemia were healthy. Blood loss/anaemia, cardiac/respiratory disorders, gastrointestinal disorders and inflammatory disorders as well as cancer were the most frequent underlying diseases. Pretreatment was noted in 39·5% (43/111) of cats and 42·4% (194/458) of dogs. The mortality rate was 37·8% (42/111) in cats and 29·7% (136/458) in dogs with reticulocytosis without anaemia; the median survival time in non-survivors was 1 day (range: 0 to 376 days in cats, 0 to 444 days in dogs).

CLINICAL SIGNIFICANCE

In both species, reticulocytosis without anaemia was observed in a low proportion of blood samples (dogs>cat). Though a bias towards sick animals is possible in our sample, reticulocytosis without anaemia was mainly seen in diseased animals and associated with a mortality rate of approximately one-third of patients.

POTENTIATION OF BROMOBENZENE-INDUCED PNEUMOTOXICITY BY PHENOBARBITAL AS DETERMINED BY BRONCHOALVEOLAR LAVAGE FLUID ANALYSIS

Bromobenzene produces pulmonary, renal and hepatic damage in the rat. Phenobarbital potentiates bromobenzene-induced hepatotoxicity. Studies were initiated to determine if phenobarbital potentiates the pulmonary damage produced by bromobenzene. In a dose ranging study, adult male rats were treated daily for 4 days with phenobarbital (80 mg/kg, ip) and on the fifth day were dosed with 0, 2, 3, or 4 mmoles/kg, ip, bromobenzene. In a larger study phenobarbital was given for 4 days (80 mg/kg, ip), and bromobenzene (3.3 mmoles/kg, ip) was given on the fifth day. Pulmonary damage was assessed 24 hours later in the first study and 12 hours later in the second study by bronchoalveolar lavage fluid analysis (BALF), microsomal mixed function oxidase measurements and histopathological evaluations. BALF biochemical markers employed were gamma-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH) and total protein. Phenobarbital treatment greatly enhanced bromobenzene-induced GGT and LDH release into the lavage fluid in a dose-dependent manner. Phenobarbital treatment increased microsomal 7-O-dealkylation of both ethoxy- and pentoxyresorufin in the liver without affecting these activities in the lung. Bromobenzene treatment decreased the hepatic microsomal dealkylation of decreased the hepatic microsomal dealkylation of pentoxyresorufin in a dose-dependent manner. Since known rat pulmonary P450 isozymes have been reported to be insensitive to phenobarbital induction, it may be that the toxicity is due to transport of a reactive metabolite(s) formed in the liver to the lung or bromobenzene is activated by some other pulmonary P450 isozyme responsive to phenobarbital.

Pretreatment tumor prostaglandin E2 concentration and cyclooxygenase-2 expression are not associated with the response of canine naturally occurring invasive urinary bladder cancer to cyclooxygenase inhibitor therapy

The purpose of this study was to determine the extent to which pretreatment prostaglandin E2 (PGE2) concentration and cyclooxygenase-2 (cox-2) expression could be used to predict the antitumor activity of cox inhibitor treatment in naturally occurring canine transitional cell carcinoma of the urinary bladder (TCC). Snap frozen tissues (to measure PGE2) and formalin-fixed TCC samples (for cox-2 immunohistochemistry) were obtained by cystoscopy or surgery. Complete tumor staging was performed before and after one month of treatment with the cox inhibitor, piroxicam (0.3 mg/kg q24 h po). The pretreatment PGE2 concentration ranged from 57 to 1624 ng/g of TCC tissue; n=18 dogs). Cox-2 immunoreactivity was observed in all TCC samples. There was no association between PGE2 concentration, cox-2 expression, and change in tumor volume with piroxicam treatment. In conclusion, cox-2 expression or PGE2 concentration alone, or the combination of the two was not useful in predicting response to piroxicam treatment in canine TCC.

Expression of cyclooxygenase-1 and 2 in naturally-occurring canine cancer

The purpose of this work was to determine cox-1 and cox-2 expression by immunohistochemistry in forms of naturally occurring canine cancer in order to identify animal systems for pre-clinical evaluation of cox inhibitors and cox-2 inhibitors in cancer. Canine lymphoma (LSA), prostatic carcinoma (PCA), osteosarcoma (OSA), oral melanoma (MEL), oral squamous cell carcinoma (SCC), oral fibrosarcoma (FSA), mammary carcinoma (MCA), and normal tissues were included. Cox-2 was expressed in epithelial tumors (17 of 26 SCC, 8 of 13 MCA, 5 of 9 PCA cases) and MEL (9 of 15 cases), but was generally absent in normal tissues. Cox-2 expression was minimal or absent in mesenchymal tumors and LSA. Cox-1 was expressed in normal epithelial tissues and in some osteoclast and osteoblast in bone, but was absent in normal lymph node. In conclusion, forms of canine cancer were identified for in vivo studies of the effects of cox inhibitors and selective cox-2 inhibitors on cancer.

Penile prolapse and urethral obstruction secondary to lymphosarcoma of the penis in a dog

A 5-year-old Chihuahua presented for clinical signs of dysuria and penile prolapse. Radiographic studies identified a urethral obstruction distal to the junction of the proximal and middle third of the os penis that appeared to be secondary to swelling of the penis. Penile resection combined with a scrotal urethrostomy was performed. Histopathological examinations of tissue samples of the body of the penis revealed lymphosarcoma. Lymphosarcoma of the penis is a rare finding in all species. It can occur as a primary tumor of the penis in dogs. Penile lymphosarcoma should be considered in the differential diagnosis of dogs affected with penile prolapse and dysuria.

Evaluation of piroxicam for the treatment of oral squamous cell carcinoma in dogs

OBJECTIVE

To evaluate the use of piroxicam for the treatment of oral squamous cell carcinoma in dogs.

DESIGN

Prospective case series.

ANIMALS

17 dogs with measurable oral squamous cell carcinoma.

PROCEDURE

Dogs were treated with piroxicam at a dosage of 0.3 mg/kg (0.14 mg/lb) of body weight, PO, every 24 hours until progressive disease or unacceptable signs of toxicosis developed or the dog died.

RESULTS

One dog had a complete remission (maxillary tumor), and 2 dogs had partial remissions (lingual tumor and tonsillar tumor). An additional 5 dogs had stable disease, including 1 with a maxillary tumor, 2 with mandibular tumors, and 2 with tonsillar tumors. Variables associated with tumor response were not identified. Median and mean times to failure for the 3 dogs that had a remission were 180 and 223 days, respectively. Median and mean times to failure for the 5 dogs with stable disease were 102 and 223 days, respectively. Time to failure was positively associated with tumor response and negatively associated with tumor size. One dog had mild adverse gastrointestinal tract effects that resolved with the addition of misoprostol to the treatment regimen.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that piroxicam may be useful in the treatment of dogs with oral squamous cell carcinoma; response rate was similar to that reported for other cytotoxic treatments. Larger-scale studies are warranted to determine what role piroxicam may have, alone or in combination with other treatments, for the treatment of dogs with oral squamous cell carcinoma.

Clinical signs, evaluation of bronchoalveolar lavage fluid, and assessment of pulmonary function in horses with inflammatory respiratory disease

OBJECTIVE

To evaluate the association among clinical signs, results of cytologic evaluation of bronchoalveolar lavage (BAL) fluid, and measures of pulmonary function in horses with inflammatory respiratory disease.

ANIMALS

9 healthy horses, 5 horses with inflammatory airway disease (IAD), and 9 horses with chronic obstructive pulmonary disease (COPD).

PROCEDURES

Clinical examination, lung function tests, and BAL were performed on each horse.

RESULTS

Standard lung mechanics of horses with exacerbated COPD differed significantly from those of healthy horses; however, there were few differences among horses with IAD, horses with COPD during remission, and healthy horses. Most variables for forced expiration (FE) in horses with COPD or IAD differed significantly from those for healthy horses. Results of clinical examination had low to moderate sensitivity and predictive values for a diagnosis of COPD (range, 67 to 80%). Results of FE tests had high sensitivity, specificity, and predictive values for a diagnosis of COPD (79 to 100%), and results of standard lung mechanics tests had low sensitivity and predictive values (22 to 69%). Percentage of neutrophils in BAL fluid was highly sensitive (100%) but moderately specific (64%) for a diagnosis of COPD.

CONCLUSIONS AND CLINICAL RELEVANCE

Clinical examination is moderately accurate for establishing a diagnosis of COPD. Forced expiration tests can specifically detect early signs of airway obstruction in horses with COPD and IAD that may otherwise be inapparent. Cytologic evaluation of BAL fluid allows early detection of inflammatory respiratory disease, but it is not specific for COPD.

Prostaglandin E2 concentrations in naturally occurring canine cancer

The purpose of this study was to determine the PGE2 concentration in naturally-occurring cancer in pet dogs and in canine cancer cell lines in order to identify specific types of canine cancer with high PGE2 production which could serve as preclinical models to evaluate anticancer strategies targeting PGE2. PGE2 concentrations were measured by enzyme immunoassay in canine melanoma, soft tissue sarcoma, transitional cell carcinoma, osteosarcoma, and prostatic carcinoma cell lines; in 80 canine tumor tissue samples including oral melanoma (MEL), oral squamous cell carcinoma (SCC), transitional cell carcinoma of the urinary bladder (TCC), lymphoma (LSA), mammary carcinoma (MCA), osteosarcoma (OSA), prostatic carcinoma (PCA); and in corresponding normal organ tissues. High concentrations of PGE(2)(range 400-3300 pg/10(4)cells) were present in cell culture medium from the transitional cell carcinoma, prostatic carcinoma, and osteosarcoma cell lines. PGE2 concentrations in tumor tissues were elevated (tumor PGE2 concentration>mean+2X sd PGE(2)concentration of normal organ tissue) in 21/22 TCC, 5/6 PCA, 7/10 SCC, 5/10 MEL, 3/8 MCA, 4/15 OSA, and 0/9 LSA. Results of this study will help guide future investigations of anticancer therapies that target cyclooxygenase and PGE2.

Cisplatin versus cisplatin combined with piroxicam in a canine model of human invasive urinary bladder cancer

PURPOSE

More than 12,000 people are expected to die from invasive transitional cell carcinoma (TCC) of the urinary bladder each year in the United States, indicating that more effective therapy is needed. Drugs inhibiting cyclooxygenase (cox) have recently been found to have chemopreventive and antitumor activity and may potentiate the effects of chemotherapy. The purpose of this study was to determine whether cisplatin combined with the cox-inhibitor piroxicam would induce remission more frequently than cisplatin alone in a relevant animal model of human invasive TCC.

METHODS

Pet dogs with naturally occurring, histopathologically confirmed, measurable TCC of the urinary bladder were randomized to receive cisplatin (60 mg/m2 i.v. every 21 days) or cisplatin (same dosage) combined with piroxicam (0.3 mg/kg orally every 24 h). Complete staging was performed prior to and at 6-week intervals during therapy.

RESULTS

After eight dogs had been evaluated in each treatment group, a significant difference in remission rate was noted (Fisher's Exact test, P < 0.004). Tumor responses in the cisplatin/piroxicam group included two complete remissions (CR), four partial remissions (PR), two stable disease (SD), and no progressive disease (PD). Tumor responses to cisplatin alone in eight dogs were no CR, no PR, four SD, and four PD. Six additional dogs were treated with cisplatin/piroxicam, and in total 10 of 14 dogs had remission (two CR, eight PR). Renal toxicity of cisplatin/ piroxicam was frequent and dose limiting.

CONCLUSIONS

Cisplatin/piroxicam induced remission more frequently than cisplatin alone in a canine model of human invasive TCC. Strategies to reduce renal toxicity need to be developed prior to evaluation of cisplatin/piroxicam in humans or general use of this treatment in pet dogs.

Diagnosis of sporotrichosis in a donkey using direct fluorescein-labeled antibody testing

A 4-year-old female donkey residing in an open field in Indiana was admitted for evaluation of facial lesions of 2 years duration. Cytologic and histologic examination of exudate and tissue from the lesions revealed a pyogranulomatous inflammatory reaction with numerous yeasts. Sporothrix schenckii was suspected to be the infectious agent; however, multiple culture attempts did not provide positive identification of the organism. Serologic examination supported infection with S. schenckii. A specific direct immunofluorescent antibody test performed on paraffin-embedded tissue sections confirmed the organism as S. schenckii. Clinical signs resolved after appropriate iodide therapy.

Metabolism of styrene by mouse and rat isolated lung cells

Styrene is pneumotoxic in mice. It is metabolized by pulmonary microsomes of both mouse and rat to styrene oxide (SO), presumed to be the toxic metabolite of styrene, and known to be genotoxic. To determine which pulmonary cell types are responsible for styrene metabolism, and which cytochromes P450 are associated with the bioactivation of styrene, we isolated enriched fractions of mouse and rat Clara and type II cells in order to determine the rate of styrene metabolism, with and without chemical inhibitors. Mouse Clara cells readily metabolized styrene to SO. Diethyldithiocarbamate, a CYP2E1 inhibitor, caused less inhibition of SO formation in Clara cells isolated from mice than previously found with pulmonary microsomes. As in microsomes, 5-phenyl-1-pentyne, a CYP2F2 inhibitor, inhibited the formation of both enantiomers. alpha-Naphthoflavone, a CYP1A inhibitor, did not inhibit SO formation in Clara cells. alpha-Methylbenzylaminobenzotriazole, a CYP2B inhibitor, exhibited minimal inhibition of SO production at 10 microM and less at 1 microM. The microsomal and isolated cell studies indicate that CYP2E1 and CYP2F2 are the primary cytochromes P450 involved in pulmonary styrene metabolism. Styrene metabolizing activity was much greater in Clara cells than in type II pneumocytes, which demonstrated essentially no activity. Styrene-metabolizing activity was several-fold higher in the mouse than in rat Clara cells. The more pneumotoxic and genotoxic form, R-SO, was preferentially formed in mice, and S-SO was preferentially formed in rats. These findings indicate the importance of Clara cells in styrene metabolism and suggest that differences in metabolism may be responsible for the greater susceptibility of the mouse to styrene-induced toxicity.

Avian pox in sanderlings from Florida

Asian pox was diagnosed in three sanderlings (Calidris alba) on Sanibel Island, Florida (USA) in February 1997. All three cases had large tumor-like lesions which contributed significantly to their mortality. Poxvirus infection was confirmed by cytology, histopathology, and electron microscopy. This is the first report of poxvirus infection in sanderlings.

Discospondylitis in association with an intra-abdominal abscess in a dog

An 11-year-old German shepherd dog cross was presented with a six-week history of weight loss and abdominal distension. A diagnosis of abdominal abscess and discospondylitis was made. The dog responded to surgical excision of the abscess and conservative medical treatment for discospondylitis.

Minimal effects of acrylonitrile on pulmonary and hepatic cell injury enzymes in rats with induced cytochrome P450

Acrylonitrile (AN) has many industrial applications but is a known carcinogen in animals and a suspect human carcinogen. Its toxicity is generally associated with its bioactivation, the initial step of which is epoxidation by cytochrome P450. While the hepatotoxicity and pneumotoxicity of AN in naive rats is generally low, the purpose of this study was to investigate the pneumotoxicity and hepatotoxicity of AN in adult male Sprague-Dawley rats and evaluate interactions with agents that may alter its metabolism. Five agents, phenobarbital, beta-naphthoflavone, pyridine, ethanol, and acetone, were administered prior to AN as inducers of CYP2B, CYP1A, and CYP2E1. Pneumotoxicity was measured as increases in y-glutamyltranspeptidase (GGT) and lactate dehydrogenase (LDH) in bronchoalveolar lavage fluid (BALF). Hepatotoxicity was measured as increases in serum sorbitol dehydrogenase (SDH). AN (1 mmol/kg ip) had little effect on liver or lung, even when given following most of the inducing agents. AN (1.5 mmol/kg) caused an increase in GGT, but had little effect on SDH or LDH. Acetone plus AN caused an increase in mortality and some indication of pneumotoxicity, but lung and liver were histologically normal. Thus AN alone even at a high dose had no effect on the liver or lung and minimal effects following induction of cytochrome P450 by acetone.

Phase II clinical trial of carboplatin in canine transitional cell carcinoma of the urinary bladder

Fourteen dogs with histologically-confirmed transitional cell carcinoma (TCC) of the urinary bladder were treated with 300 mg/m2 carboplatin every 3 weeks. Response to therapy was assessed with abdominal radiography, double contrast cystography, urinary bladder ultrasonography and thoracic radiography before therapy and at 6-week intervals during therapy. Dogs were monitored for hematologic toxicity with a CBC and platelet count performed immediately before and 10 to 14 days after carboplatin treatment. Tumor responses included progressive disease in 11 dogs and stable disease in 1 dog. Two dogs were euthanized due to carboplatin toxicity before assessment of tumor response. Toxicity included thrombocytopenia with or without neutropenia in 7 dogs and gastrointestinal toxicity in 6 dogs. Carboplatin therapy was not beneficial in the treatment of TCC in the 14 dogs in this study.

Effect of cytoxan-induced heteropenia on the response of specific-pathogen-free chickens to infectious bronchitis

Epithelial damage in infectious bronchitis occurs early in the disease process. Heterophil infiltration into the tracheal mucosa is greatest at that time. To determine the contribution of heterophils to tracheal epithelial damage of infectious bronchitis, eight 3-wk-old specific-pathogen-free chickens were made heteropenic by four daily intramuscular injections of cyclophosphamide at 75 mg/kg body weight. Infection with Massachusetts 41 infectious bronchitis virus was timed to coordinate heteropenia with peak tracheal epithelial damage. Heteropenia was monitored by total leukocyte and differential cell counts of peripheral blood. Tissue damage and heterophil infiltrate were monitored by histopathology of tissues taken at termination of the study. Heteropenic birds had lower peripheral blood and tracheal heterophil numbers than nonheteropenic birds. No difference was found in epithelial damage of heteropenic and nonheteropenic birds. Epithelial damage in infectious bronchitis is most likely due to damage by the virus and not due to the infiltrated heterophils.

Effects of glucocorticoid therapy on urine protein-to-creatinine ratios and renal morphology in dogs

Glomerulonephritis has been associated with exogenous glucocorticoid administration and spontaneous hyperadrenocorticism in the dog. The purpose of this study was to determine the effects of long-term glucocorticoid therapy on urine protein:creatinine ratios (UP/Cs) and renal morphology. Nine young-adult male dogs were determined to be healthy and have normal renal function as assessed by physical examination, CBC, serum biochemistry analysis, Knott's test for Dirofilaria immitis, urinalysis, urine culture, urine protein electrophoresis, endogenous creatinine clearance, 24-hour urinary protein excretion, and UP/C. Prednisone was administered to each dog at a dosage of 2.2 mg/kg PO bid for 42 days. Urinalysis and UP/C were performed on days 0, 7, 14, 21, 28, and 42 of treatment. Mean UP/C on day 0 was 0.29 +/- 0.10. Mean UP/C increased progressively to a maximum of 1.27 +/- 1.02 on day 28. Mean UP/C on day 42 decreased slightly (0.92 +/- 0.56) but remained significantly increased above baseline. The most consistent renal light microscopic finding on necropsy examination was generalized hypercellular glomerular tufts, suggestive of mesangial cell proliferation. Four dogs also had occasional adhesions of glomerular tufts to Bowman's capsule, accompanied by thickening of the capsule. Direct immunofluorescence for immunoglobulin deposition was negative in all dogs. Electron microscopy, evaluated in 7 dogs, was characterized by occasional mild segmental thickening of basement membranes, fusion of visceral cell foot processes, and glomerular adhesions. The results of this study indicate that long-term administration of glucocorticoids results in significant proteinuria and glomerular changes in the dog.

Apocrine gland adenocarcinoma and pheochromocytoma in a cat

A 15-year-old, castrated male domestic shorthair was presented for a recurrent, perineal apocrine gland adenocarcinoma. A right adrenal mass was identified on abdominal radiography and ultrasonography performed as routine staging prior to surgical excision of the perineal tumor. An ultrasonographic-guided biopsy of the adrenal mass was performed and a pheochromocytoma was diagnosed upon histopathology. The perineal and adrenal tumors were removed surgically. The cat developed fatal thromboembolic disease following surgery and was euthanized. This is the third reported case of phenochromocytoma in a cat and is unusual in that two rare tumors were identified in one animal.

Cisplatin treatment of transitional cell carcinoma of the urinary bladder in dogs: 18 cases (1983-1993)

OBJECTIVE

To determine whether cisplatin administered at a dosage of 60 mg/m2 of body surface area, IV, every 21 days, would induce remission of transitional cell carcinoma of the urinary bladder in dogs.

DESIGN

Retrospective analysis of medical records.

ANIMALS

18 dogs with histologically confirmed transitional cell carcinoma of the urinary bladder.

PROCEDURE

Clinical staging was performed by means of physical examination, contrast cystography or ultrasonography, and thoracic radiography prior to and 42 days after the initiation of cisplatin treatment. Dogs with clinical signs of tumor progression were reevaluated earlier than 42 days in some instances. Complete remission (CR) was defined as complete resolution of measurable tumor. Partial remission (PR) was defined as a > or = 50% reduction in tumor volume without development of new tumors. Stable disease was defined as < 50% change in tumor volume at 42 days without development of new lesions. Progressive disease (PD) was defined as > or = 50% increase in tumor volume or development of new tumors at any time. Dogs were reevaluated at 42-day intervals until they had a CR, developed PD, or developed unacceptable adverse effects.

RESULTS

Three dogs had a PR, 4 had stable disease, and 9 had PD. Tumor response could not be assessed in 2 dogs: 1 dog developed grand mal seizures 3 hours after the first dose of cisplatin was given and was euthanatized; the other dog continued to have clinical signs of urinary tract obstruction and was euthanatized 8 days after the first dose of cisplatin. Four dogs developed renal azotemia that was suspected to be secondary to cisplatin nephrotoxicity.

CLINICAL IMPLICATIONS

The cisplatin dosage was higher than that reported in studies of dogs with transitional cell carcinoma of the bladder. Even with this higher dosage, none of the dogs had a CR, and only 3 of 18 had a PR. A more effective, less toxic treatment for transitional cell carcinoma in dogs is needed.

Nephrotoxicity of amphotericin B administered to dogs in a fat emulsion versus five percent dextrose solution

OBJECTIVE

To determine whether administration of amphotericin B in a fat emulsion solution would reduce the nephrotoxicity of amphotericin B, compared with that associated with administration of amphotericin B in 5% dextrose solution.

DESIGN

Prospective controlled study.

ANIMALS

2 groups of 5 adult male Beagles.

PROCEDURE

Dogs received amphotericin B (1 mg/kg of body weight/d) prepared in 5% dextrose solution or in 20% fat emulsion daily for 6 doses. Serum biochemical analysis, CBC, urinalysis, and endogenous creatinine clearance was performed on days 0 and 8, 2 days after the last dose of amphotericin B. On day 8, dogs were euthanatized and gross necropsies were performed. Unbiased semiquantitative scoring of the kidneys for the degree of injury was performed by use of light microscopy.

RESULTS

There were no significant differences in serum creatinine, urea nitrogen, or potassium concentrations, urine specific gravity, endogenous creatinine clearance, or degree of tubulo-interstitial injury between the 2 groups.

CONCLUSION

In this model, the degree of nephrotoxicity of amphotericin B was not significantly different for dogs receiving the drug in a fat emulsion versus its administration in 5% dextrose.

Pneumotoxicity and hepatotoxicity of styrene and styrene oxide

The purpose of this study was to investigate the toxicity of styrene and styrene oxide in the lung in comparison to the toxicity in the liver. Pneumotoxicity caused by styrene or styrene oxide was measured by elevations in the release of gamma-glutamyltranspeptidase (GGT) and lactate dehydrogenase (LDH) into bronchoalveolar lavage fluid (BALF), while hepatotoxicity was measured by increases in serum sorbitol dehydrogenase (SDH) in non-Swiss Albino (Hsd:NSA) mice. Intraperitoneal administration of styrene at doses of 500-1000 mg/kg caused consistent dose-dependent increases in both sets of biomarkers with the hepatic effect appearing earlier than the pulmonary effect. Pyridine, phenobarbital, and beta-naphthoflavone, inducers of CYP2E1, CYP2B, and CYP1A, respectively, increased the toxicity of styrene. Pyridine and phenobarbital treatments increased mortality due to styrene. Styrene oxide exists in two enantiomeric forms: (R)- and (S)-styrene oxide, and the differential toxicities of the two enantiomers and racemic styrene oxide were compared. In all studies, (R)-styrene oxide caused greater toxicity than the (S) enantiomer, especially in the liver. Trichloropropene oxide, an epoxide hydrolase inhibitor, was used to inhibit styrene oxide detoxification and increased its hepatotoxicity, while buthionine sulfoxamine, a glutathione depletor, did not. These results demonstrated the greater role of epoxide hydrolase in styrene oxide detoxification.

Pancreatic pseudocyst associated with chronic-active necrotizing pancreatitis in a cat

A 13-year-old, neutered female domestic shorthair was referred for evaluation of chronic, intermittent vomiting of approximately two years' duration. On physical examination, a fluctuant mass was palpated in the left cranial abdominal quadrant. Significant laboratory findings included neutrophilia, hyperglycemia, hyperlipasemia, and proteinuria. A distinct mass within the left cranial quadrant was noted on abdominal radiographs. Ultrasonographically, the pancreas appeared slightly hyperechoic with a hypoechoic mass arising from its left lobe. A cystic mass in the left lobe of the pancreas was identified during an exploratory celiotomy. The mass and affected areas of the pancreas and a portion of the spleen were resected. The cat recovered completely. Cytological, histological, and laboratory evaluations of the mass were consistent with pancreatic pseudocyst formation, which has been reported in dogs and humans but has not yet been reported in cats.

Cyclophosphamide (Cytoxan)-induced hematologic alterations in specific-pathogen-free chickens

Cyclophosphamide (Cytoxan) was given at 75 mg/kg body weight via daily intramuscular injections for 4 days to 3-week-old specific-pathogen-free (SPF) chickens in an attempt to determine if heteropenia could be induced in chickens. Control birds were given a like quantity of phosphate-buffered saline, the diluent for Cytoxan. Peripheral blood heterophil numbers were determined and monitored by total leukocyte and differential cell counts. Birds were grouped in pairs on day 0 based on total leukocyte count. The number of heterophils each bird had on day 0 served as a baseline heterophil count for that bird. Thereafter heterophil numbers were determined on the last day of drug treatment and every other day until blood heterophil numbers were 20% of that bird's baseline heterophil count (heteropenia). The effects of Cytoxan on trachea, lung, liver, kidney, bursa of Fabricius, bone marrow, spleen, and thymus were determined by microscopic examination of those tissues collected the day following heteropenia. Cytoxan had no effect on trachea, lung, liver, kidney, and thymus. Bursa of Fabricius and spleen had decreased amounts of lymphoid aggregates. Bone marrow of Cytoxan-treated chickens was hypocellular. The study was then repeated to determine the reversibility of Cytoxan-induced heteropenia. Cytoxan-treated birds were allowed to recover until blood heterophil numbers equaled or exceeded those of control birds. Cytoxan, through bone marrow suppression, induced a reversible heteropenia that developed between treatment days 10 and 12. In addition, Cytoxan induced a reversible lymphocytopenia between days 4 and 10 and a regenerative anemia between days 8 and 10. The ability to produce heteropenia in SPF chickens will allow the use of a heteropenic model for further study of the heterophil's contribution to the inflammatory response.

Ultrastructure and cytochemical staining characteristics of canine natural killer cells

BACKGROUND

The purpose of this work was to describe the ultrastructure and cytochemical staining characteristics of canine peripheral blood lymphocytes with natural killer (NK) cell activity, with comparison made to non-NK lymphocytes.

METHODS

Canine lymphocyte populations evaluated for ultrastructure, cytochemical staining, and NK function (by 51chromium release assay) included: peripheral blood lymphocytes; lymphocytes from band 1 (NK-enriched), band 2, and the pellet of a 45/50% percoll gradient; lymphocytes from the supernatant fluid (non-conjugated lymphocytes) and pellet (lymphocytes conjugated to tumor cell targets) of a 17% percoll gradient; and null (CD4-CD8-) and CD4-CD8+ lymphocytes.

RESULTS

NK activity was concentrated in band 1 lymphocytes of the 45/50% percoll gradient with further enhancement of activity occurring in sorted null cells. Canine NK cells were 5.5 to 6.5 microns in diameter with a reniform (kidney bean shape) nucleus, and electron-dense cytoplasmic granules. NK cells (percoll band 1 cells and null cells) had larger cell and nuclear area, and less round nuclei when compared to non-NK lymphocytes. The overall cytochemical staining (chloracetate esterase, peroxidase, sudan black B, naphthyl acetate esterase, naphthyl butyrate esterase periodic acid-Schiff stain, and acid phosphatase with and without tartrate) pattern was similar in all the lymphocyte populations evaluated.

CONCLUSIONS

This work confirms the usefulness of a 45/50% percoll gradient in obtaining a NK-enriched fraction of canine lymphocytes, and shows further enhancement of NK activity in sorted CD4- CD8- cells. The ultrastructure of canine NK cells is similar to that reported for human NK cells, but is different from that of other canine peripheral blood lymphocytes. Standard cytochemical staining does not discriminate canine NK cells from other lymphocytes.

Total laryngectomy and permanent tracheostomy for treatment of laryngeal rhabdomyosarcoma in a dog

An extensive, laryngeal tumor was identified in a nine-year-old, spayed female, mixed-breed dog. Clinical staging of the tumor included computed tomography. Six days prior to surgery, a percutaneous gastrostomy tube was placed under endoscopic guidance. Surgical treatment included total laryngectomy and permanent tracheostomy. The histologic diagnosis of the tumor was rhabdomyosarcoma. There were no major postoperative complications, and there have been no signs of local recurrence, metastatic disease, or long-term complications associated with the surgical procedure during an 18-month follow-up period.

Cytological analysis of bronchoalveolar lavage fluid in the diagnosis of spontaneous respiratory tract disease in dogs: a retrospective study

Results of cytological analysis of bronchoalveolar lavage (BAL) fluid were compared with clinical diagnoses in dogs that presented with signs of respiratory disease to referral hospitals. Of 68 dogs in which a clinical diagnosis was possible, BAL cytological findings were considered definitive for the diagnosis in 17 cases (25%), supportive of the diagnosis in 34 cases (50%), and not helpful in 17 cases (25%). Findings were most often considered supportive of or definitive for the clinical diagnosis in dogs with alveolar or bronchial radiographic patterns, or the presence of pulmonary masses. BAL results among lung lobes differed in 23 of 63 dogs (37%) with diffuse radiographic patterns. Tracheal wash cytology differed from BAL fluid cytology in 45 of 66 dogs (68%). Bronchoalveolar lavage was a clinically useful procedure for the diagnostic evaluation of dogs with signs of respiratory disease.

Response to high-dose radioactive iodine administration in cats with thyroid carcinoma that had previously undergone surgery

Seven cats with thyroid carcinomas that had previously undergone surgical removal of neoplastic tissue were treated with 30 mCi of radioactive iodine (131I). Six of the cats had clinical signs of hyperthyroidism; 1 did not. There were no complications associated with 131I treatment, and clinical signs resolved in all cats. Technetium scans of 4 cats made after treatment did not have evidence of isotope uptake. In the remaining 3 cats, small areas of isotope uptake, the intensity of which was equal to or less than the intensity of uptake in the salivary glands, were seen. All 7 cats became hypothyroid after treatment; 4 required L-thyroxine supplementation. One cat was alive 33 months after treatment. The other 6 cats were euthanatized because of unrelated diseases 10 to 41 months after treatment.

Treatment of nonregenerative anemia with human gamma-globulin in dogs

Five dogs with nonregenerative anemia were treated with human immunoglobulin as a 12-hour IV infusion, at dosages ranging from 0.5 to 1.5 g/kg of body weight. All dogs had a rapid response to treatment, with reticulocytosis within 1 to 4 days and a substantial increase in hematocrit within 3 to 8 days of treatment. In 2 of 5 dogs, the hematocrit returned to values within reference range and remained in the reference range for 8 to 14 months after treatment, despite discontinuing or tapering prednisone treatment to a low dose. In 3 of 5 dogs, the hematocrit did not return to the reference range. In 1 of these 3 dogs, the hematocrit remained at the new, increased value (26 to 28%) for 248 days after treatment, at which time the dog was euthanatized. In the other 2 dogs, the hematocrit had decreased to pretreatment values by 52 days after treatment. Retreatment of these 2 dogs resulted in a similar, but blunted, response to human immunoglobulin. Human immunoglobulin may be an effective treatment for some dogs with immune-mediated anemia that fail to respond to conventional treatment.

Biliary epithelial cell proliferation following alpha-naphthylisothiocyanate (ANIT) treatment: relationship to bile duct obstruction

These studies were designed to evaluate the importance of bile duct obstruction in the pathogenesis of alpha-naphthylisothiocyanate (ANIT)-induced biliary epithelial cell (BEC) hyperplasia in rats. Hepatobiliary function and morphology were evaluated in adult male Sprague-Dawley rats 16, 24, 48, 72, 120, and 168 hr after a single oral dose of ANIT (0, 25, 75, or 150 mg/kg). After 75 or 150 mg/kg ANIT, multifocal bile duct obstruction was observed at 48 and 72 hr and preceded BEC hyperplasia which occurred at 120 and 168 hr. BEC proliferation, reflected by 5-bromo-2'-deoxyuridine (BrdU) incorporation, occurred at doses and at time points coinciding with BEC necrosis and/or bile duct obstruction. In contrast, 25 mg/kg ANIT produced minimal BEC damage and no evidence of bile duct obstruction or BEC hyperplasia. In a separate experiment, BEC proliferation was evaluated following bile duct ligation or ANIT treatment (150 mg/kg). The onset and peak of BEC proliferation occurred 24 and 48 hr, respectively, following bile duct obstruction resulting from either ligation or ANIT treatment. Furthermore, BEC proliferation occurred at all levels of the biliary tree in both bile duct-ligated and ANIT-treated rats. These data indicate that (a) dose-response curves for ANIT-induced bile duct obstruction and BEC hyperplasia are similar; (b) ANIT-induced BEC proliferation and bile duct obstruction precedes BEC hyperplasia; (c) BEC proliferation occurred at doses/timepoints associated with BEC damage and bile duct obstruction; and (d) once ANIT-induced bile duct obstruction occurs, the spatial and temporal aspects of BEC proliferation are comparable to those following biliary obstruction induced by bile duct ligation. Collectively, these data suggest that ANIT-induced BEC hyperplasia is secondary to intrahepatic bile duct obstruction.

Immunoreactivity of canine epithelial and nonepithelial neoplasms with monoclonal antibody B72.3

Monoclonal antibody (MAb) B72.3, which binds to a human tumor-associated glycoprotein termed TAG-72, was applied to a wide range of epithelial and nonepithelial neoplasms from dogs. Immunoreactivity was detected by the use of an avidin-biotin complex (ABC) immunoperoxidase method. A variety of epithelial neoplasms, but none of the nonepithelial neoplasms, were positive (> or = 5% staining) for MAb B72.3. MAb B72.3 stained 100% (4/4) of gastric, 100% (6/6) of intestinal, 50% (2/4) of pancreatic, and 80% (4/5) of rectal adenocarcinomas but only 20% (1/5) of squamous cell carcinomas and 20% (1/5) of complex tubular mammary gland adenocarcinomas. None of the hepatocellular carcinomas and perianal and sebaceous gland adenocarcinomas stained. Most types of benign epithelial neoplasms did not stain, except for 75% (6/8) of rectal adenomas and 25% (1/4) of squamous cell papillomas. Normal gastrointestinal mucosa adjacent to and entrapped in neoplasms did stain with MAb B72.3. None of the benign and malignant nonepithelial neoplasms of mesenchymal, neuroendocrine, or lymphohematopoietic tissue origin stained. The results of this study demonstrate that MAb B72.3 has selective immunoreactivity for adenocarcinomas, especially those arising from the digestive tract; however, limited immunoreactivity was observed for other types of carcinomas and benign epithelial neoplasms and for normal gastrointestinal mucosa in the dog.

Immunoreactivity of canine transitional cell carcinoma of the urinary bladder with monoclonal antibodies to tumor-associated glycoprotein 72

Tumor-associated glycoprotein 72 (TAG-72) is a large, high molecular weight, mucinlike antigen that is expressed in a wide variety of human carcinomas. Three different TAG-72 monoclonal antibodies (MAbs), designated B72.3, CC49, and CC83, were applied to the following archived samples from the dog: 1) 51 transitional cell carcinomas of the urinary bladder, 2) 15 hyperplastic/inflamed urinary bladders, and 3) eight normal urinary bladders. Immunoreactivity was detected with an avidin-biotin complex immunoperoxidase method. Fifty-three percent (27/51) of transitional cell carcinomas were positive (> or = 5% staining) for MAb B72.3. MAb B72.3 staining of these transitional cell carcinomas did not statistically correlate with any of the examined features of malignancy, including histologic grade, clinical stage, DNA ploidy, or presence of vascular/lymphatic invasion. In regard to the staining of transitional cell carcinoma by the other two TAG-72 antibodies, 53% (27/51) of the samples were positive for MAb CC83 and 63% (32/51) were positive for MAb CC49. The finding that similar populations of neoplastic urothelial cells in serial sections from the same neoplasm stained with all three TAG-72 antibodies supports the hypothesis that an antigen similar to TAG-72 was expressed in canine transitional cell carcinoma. None of the normal urinary bladders nor any of the hyperplastic/inflamed urinary bladders stained with any of the three TAG-72 antibodies tested. The results of these studies demonstrated that the staining of canine transitional cell carcinoma with all three TAG-72 antibodies was specific for neoplastic urothelial cells and that an antigen similar to TAG-72 was expressed.

Giant cell variant of malignant fibrous histiocytoma in dogs: 10 cases (1986-1993)

Signalment, tumor sites, clinicopathologic, radiographic, and ultrasonographic features, as well as treatment protocols and survival information, were evaluated for 10 dogs with a histologic diagnosis of giant cell variant of malignant fibrous histiocytoma. Common clinical findings included subcutaneous masses, weight loss, anorexia, and lethargy. Laboratory abnormalities included anemia, hypoalbuminemia, and high concentrations of serum hepatic enzymes. Radiography and ultrasonography were useful in staging the extent of metastasis. Seven dogs had tumor metastasis at the time of diagnosis. Two other dogs developed evidence of metastasis during the course of treatment. The most common sites of tumor involvement were subcutaneous tissues, lymph nodes, liver, and lungs. Treatment protocols included surgical resection, intraoperative radiotherapy, and chemotherapy. Median survival time of all dogs was 61 days. Median survival time of the 6 treated dogs was 161 days. Findings on necropsy revealed metastasis with multiple organ involvement. The giant cell variant of malignant fibrous histiocytoma was determined to be a highly metastatic neoplasm in dogs, which may be responsive to surgical excision, chemotherapy, or radiotherapy.

Evaluation of immunoreactivity of normal tissues from dogs, using monoclonal antibody B72.3

Monoclonal antibody (MAB) B72.3, which recognizes human tumor-associated glycoprotein-72, has immunoreactivity for malignant epithelial neoplasms in human beings and dogs. To further characterize the range of immunoreactivity of MAB B72.3 in canine tissues, MAB B72.3 and 2 other tumor-associated glycoprotein-72 antibodies (MAB CC49 and CC83) were tested against a wide spectrum of normal tissues from dogs. Immunoreactivity was detected, using an avidin-biotin-complex immunoperoxidase method. Monoclonal antibody B72.3 did not stain most types of normal canine tissues, but various types of epithelial cells within the gastrointestinal and respiratory tract mucosae, salivary gland, esophagus, epididymis, uterus, thymus, hair follicle, and apocrine glands of the anal sac had variable staining with MAB B72.3. A similar range of immunoreactivity in comparable types of normal tissues was seen for MAB CC49 and CC83; however, MAB CC49, but not MAB B72.3 and CC83, stained the endothelium of capillaries and small vessels in most normal tissues. Staining of frozen and paraffin-embedded tissues was similar. In conclusion, we found that MAB B72.3, CC49, and CC83 had selected immunoreactivity for specific types of normal canine epithelial cells, especially those involved with mucin production.

Piroxicam therapy in 34 dogs with transitional cell carcinoma of the urinary bladder

Thirty-four dogs with histopathologically confirmed, measurable, nonresectable transitional cell carcinoma of the urinary bladder were treated with piroxicam (0.3 mg/kg PO sid) and were evaluated for tumor response and drug toxicity. Dogs were evaluated at the Purdue University Veterinary Teaching Hospital by means of physical examination, thoracic and abdominal radiography, cystography, complete blood count, serum biochemistry profile, and urinalysis. In selected cases, prostaglandin E2 (PGE2) concentrations in plasma and in supernatants of stimulated monocytes, and natural killer cell activity were quantified. Dogs were evaluated before therapy and at 28 and 56 days after initiation of therapy. Dogs with stable disease or remission at 56 days remained on the study and were evaluated at 1 to 2 months intervals. Tumor responses were 2 complete remissions, 4 partial remissions, 18 stable diseases, and 10 progressive diseases. The median survival of all dogs was 181 days (range, 28 to 720+ days), with 2 dogs still alive. Piroxicam toxicity consisted of gastrointestinal irritation in 6 dogs and renal papillary necrosis (detected at necropsy) in 2 dogs. Monocyte production of PGE2 appeared to decrease with therapy in dogs whose tumors were decreasing in size, and increased in dogs with tumor progression. A consistent pattern in natural killer cell activity was not observed. In vitro cytotoxicity assays against 4 canine tumor cell lines revealed no direct antitumor effects of piroxicam. In summary, antitumor activity, which was not likely the result of a direct cytotoxic effect, was observed in dogs with transitional cell carcinoma of the bladder treated with piroxicam.

Flow cytometric DNA ploidy analysis in canine transitional cell carcinoma of urinary bladders

Flow cytometric analysis of DNA ploidy was performed on 51 formalin-fixed, paraffin-embedded samples of canine transitional cell carcinoma of the urinary bladder. The DNA ploidy data obtained were compared to several clinicopathologic features. In addition, the DNA ploidy of 15 hyperplastic/inflamed and 8 normal canine urinary bladders was measured. Forty-three of the 51 neoplastic samples had interpretable DNA histograms. DNA aneuploidy was found in 34/43 (79%) of the transitional cell carcinoma samples. Of the 34 aneuploid neoplasms, 16 (47%) were hyperdiploid, 17 (50%) were tetraploid, and 1 (3%) was hypertetraploid. No significant correlation was found between the presence of DNA aneuploidy and the growth pattern, histologic grade, clinical stage, or individual morphologic features of this neoplasm. Additionally, the DNA ploidy was not related to the sex, age, or survival time of dogs with transitional cell carcinoma. All of the normal and all but one of the hyperplastic/inflamed urinary bladders were diploid. The results from this study demonstrated that DNA ploidy can be measured from paraffin-embedded canine samples by flow cytometry, a majority of the canine transitional cell carcinomas were aneuploid, and a significant correlation did not exist between the DNA ploidy and specific clinicopathologic features of this neoplasm.

Confirmation of a pulmonary component of multicentric lymphosarcoma with bronchoalveolar lavage in two dogs

Histologic examination of lung tissue has been the only definitive diagnostic procedure used to confirm pulmonary involvement with lymphosarcoma (LSA) in dogs. Lung involvement with LSA was diagnosed by cytologic examination of bronchoalveolar lavage fluid in 2 dogs with multicentric LSA. Both dogs had cough or dyspnea, in addition to peripheral lymphadenopathy or visceral organomegaly. Both dogs had nonspecific, abnormal thoracic radiographic findings, including diffuse pulmonary interstitial pattern, hydrothorax, and mediastinal and retrosternal lymphadenopathy. In these 2 dogs, postmortem lung histologic examination, performed immediately after bronchoalveolar lavage, confirmed the cytologic diagnosis of pulmonary infiltration with LSA.

Comparison of image analysis and flow cytometric measurements of DNA content of canine transitional cell carcinomas

The DNA content of neoplasms is generally determined by flow cytometry, but quantitative microscopic image analysis is an alternative technique for DNA quantification. To compare these two methods, the DNA content of 31 paraffin-embedded canine transitional cell carcinomas was measured by flow cytometry and image analysis. Interpretable data were available for 26 samples by flow cytometry and 27 samples by image analysis. For 23 neoplasms with interpretable data by both methods, a good correlation (r = .80, P < .001) was obtained between the DNA indices determined by flow cytometry and image analysis. Concordance of DNA ploidy classification was reached in 21 samples; however, for 4 samples an aneuploid cell population, usually tetraploid, was identified by image analysis and not by flow cytometry. Two samples also had aneuploid peaks by flow cytometry and not by image analysis. Although a good correlation was seen between the measurement of DNA content of paraffin-embedded canine tissue by image analysis and flow cytometry, this study did demonstrate that aneuploid cell populations can be missed by both methods and that image analysis was better than flow cytometry in the detection of aneuploid cell populations, particularly tetraploid ones, in samples with excessive cellular debris.

Cytologic analysis of bronchoalveolar lavage fluid from 47 dogs with multicentric malignant lymphoma

Bronchoalveolar lavage (BAL) was performed in 47 dogs with multicentric malignant lymphoma (ML). Cytologic results were evaluated, and ability to detect pulmonary involvement with ML, using BAL, was compared with ability to detect pulmonary involvement, using thoracic radiography and tracheal wash. Lung lobes were considered to be involved with ML on the basis of BAL fluid findings if morphologically abnormal lymphocytes were present in the fluid. Total nucleated cell count, relative lymphocyte count, and absolute lymphocyte count were greater (P < 0.001) in BAL fluid from dogs with multicentric ML than in BAL fluid from histologically normal dogs. Pulmonary involvement with ML was detected by BAL fluid cytologic examination in 89 of 135 lung lobes lavaged (66%). Lung lobes involved with ML were from 31 of the 47 dogs with multicentric ML (66%). Radiographic abnormalities supportive of pulmonary parenchymal involvement with ML were detected in 16 of the 47 dogs (34%). Of these 16 dogs, 15 (94%) had pulmonary involvement with ML on the basis of BAL fluid cytologic findings. Tracheal wash fluid contained abnormal lymphocytes in 4 of 41 dogs (10%). In all 4 dogs, BAL fluid also contained abnormal lymphocytes. Cytologic evaluation of BAL fluid was more sensitive in detecting pulmonary involvement with ML, compared with radiographic evaluation of the lungs or tracheal wash.

Advantages and disadvantages of cytology and histopathology for the diagnosis of cancer

Histopathology and cytology are both valuable diagnostic tools. An appreciation of the virtues and the limits of each technique is essential if the user is to avoid mistakes in interpretation. It is also important to take full advantage of the many additional techniques that can be applied to cytology smears and histopathology tissue sections to gain maximum clinical information.

Potentiation of carbon tetrachloride-induced hepatotoxicity and pneumotoxicity by pyridine

Induction of P450IIE1 by pyridine was compared with that by ethanol, and the resulting potentiation of the pneumotoxicity and hepatotoxicity following carbon tetrachloride inhalation by pyridine was examined. Rats were treated with ethanol as either a 10% solution in the drinking water or as a daily bolus (3 ml/kg, ip) dose for 7 days or one bolus dose of pyridine (200 mg/kg, ip) and compared for P450IIE1 apoprotein content by immunoblot analysis. Ethanol in the drinking water and pyridine elevated both hepatic and pulmonary P450IIE1 apoprotein content, but bolus dose ethanol did not. The induction was greatest in the pyridine group. In the interaction study, rats were treated with pyridine (200 mg/kg, ip) and 12 hours later were exposed to CCl4 (8000 ppm for 3 hours). Pulmonary injury and hepatic damage were assessed 24 hours later by bronchoalveolar lavage fluid (BALF) analysis [gamma-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH), and total protein] and serum sorbitol dehydrogenase (SDH) activity, respectively. Pyridine alone had no effect on BALF or SDH but enhanced GGT and LDH release into the BALF and SDH release into the serum when compared with CCl4 exposure alone. Evaluation of the liver at the light microscopic level revealed characteristic CCl4-induced centrilobular necrosis which was potentiated by pyridine. No changes were observed in the lung by light microscopic evaluation. Pyridine induced pulmonary and hepatic microsomal apoprotein levels of cytochrome P450IIE1 two- and 2- to sixfold, respectively. Exposure to CCl4 decreased hepatic but not pulmonary P450IIE1 levels. Induction of cytochrome P450IIE1 by pyridine increases the bioactivation of CCl4 in both the liver and lung, leading to enhanced toxicity.

Immunohistochemical evaluation of canine carcinomas with monoclonal antibody B72.3

Monoclonal antibody (MAb) B72.3 reacts with a tumor-associated glycoprotein, designated TAG-72. TAG-72 has been identified in many human carcinomas but generally is not found in normal human tissues. Because of its proven utility in the diagnosis of human carcinomas, MAb B72.3 was applied to several different types of canine carcinomas. Five types of formalin-fixed, paraffin-embedded canine carcinomas were evaluated for immunoreactivity with MAb B72.3 by use of an avidin biotin immunoperoxidase complex method. Samples were considered positive when > or = 5% of all malignant cells contained a distinct intracellular stain. Immunoreactivity for MAb B72.3 was observed in 6/9 (67%) pulmonary adenocarcinomas, 7/13 (54%) transitional cell carcinomas, 7/11 (64%) mammary adenocarcinomas, 7/11 (64%) nasal adenocarcinomas, and 1/2 (50%) prostatic adenocarcinomas. The average cellular staining for positive carcinomas was 25%. Normal canine tissues from similar anatomic sites had little or no individual cell immunoreactivity. These preliminary results indicate that some canine carcinomas may express a tumor-associated antigen that is similar to TAG-72 and that MAb B72.3 immunoreactivity may be of diagnostic significance in classifying animal tumors.

Measurement of NK activity in effector cells purified from canine peripheral lymphocytes

Natural killer (NK) cells spontaneously lyse a variety of tumor cells in vitro, and are believed to play an important role in host resistance to tumor growth and metastasis in vivo. As part of our work in comparative oncology, we have designed and validated a canine NK cell assay. Of several lymphocyte isolation techniques evaluated, sedimentation of whole blood through a two-step Ficoll/Hypaque gradient (sp. gr. 1.066/1.119) followed by plastic adherence of monocytes resulted in the most pure lymphocyte population (> 95% lymphocytes). Of four cell lines evaluated as targets in the NK assay, a canine thyroid adenocarcinoma (CTAC) cell line was determined to be most sensitive, and a lymphoblastoid (CT45-S) cell line was determined to be most resistant to NK lysis. A 15 h effector-target incubation period using these targets resulted in reproducible measurement of cell specific lytic activity. Passage of canine lymphocytes through nylon wool columns did not result in a significant increase in NK activity. A final sedimentation of purified lymphocytes through a 45/50% Percoll gradient concentrated NK activity into a single band of lymphocytes. Lymphocytes forming conjugates with CTAC target cells were 5.5-6.5 microns in diameter, and were characterized by a reniform nucleus and varying numbers of electron-dense cytoplasmic granules.

Cytologic evaluation of the respiratory tract

Evaluation of respiratory tract disease is a challenge for several reasons: no serum biochemical or hematologic tests that localize injury to the respiratory system are available, imaging techniques do not usually lead to etiologic diagnoses, and excisional biopsies are often very difficult to obtain from respiratory lesions. For these reasons, specific diagnosis of respiratory tract disease often resides in cytologic evaluation. This article reviews the various cytologic collection techniques that yield high-quality specimens from the upper and lower respiratory tract. Cytologic features of the normal respiratory tract as well as common respiratory disorders are described and illustrated.

Effect of p-xylene inhalation on the bioactivation of bromobenzene in rat lung and liver

It is unclear whether the pneumotoxicity observed with bromobenzene (BB) in phenobarbital-induced rats is related to BB bioactivation in lung, liver or both. To help differentiate pulmonary from hepatic bioactivation, BB was administered alone and in combination with p-xylene, which inhibits pulmonary but induces hepatic cytochromes P450. Exposure to p-xylene alone (3400 ppm for 4 hr) produced no changes in bronchoalveolar lavage fluid (BALF) measurements (gamma-glutamyl transpeptidase, lactate dehydrogenase, protein, white blood cell count) or serum sorbitol dehydrogenase. p-Xylene increased hepatic microsomal benzyloxy- (BROD), pentoxy- (PROD), and ethoxy- (EROD) resorfuin O-dealkylase activities but decreased pulmonary microsomal BROD and PROD. Immunoblot analysis revealed an induction of hepatic but not pulmonary microsomal P450IIB apoprotein. When rats were exposed to p-xylene (2800 ppm) or room air for 4 hr, treated 12 hr later with BB (0.5 ml/kg, ip) or corn oil, and killed after 12 hr, p-xylene increased hepatic P450IIB (27-fold) concomittant with a similar increase in BROD activity. p-Xylene also increased hepatic P450IA apoprotein (3.4-fold) with a complimentary increase in EROD activity. p-Xylene potentiated BB-induced hepatotoxicity. In pulmonary microsomes p-xylene and BB each produced similar decreases in both EROD and BROD activities. The combination of p-xylene and BB had an additive effect on pulmonary P450IA1 reduction. BALF analysis and histopathology revealed no pneumotoxicity with any treatment. p-Xylene potentiation of BB-induced hepatotoxicity without pneumotoxicity suggests that the liver does not produce metabolites of BB which are directly involved in pulmonary damage.