The effects of dietary polyunsaturated fatty acids (PUFA) on ex vivo bone prostaglandin E(2) (PGE(2)) production and bone formation rate were evaluated in rats. Weanling male Sprague-Dawley rats were fed AIN-93G diet containing 70 g/kg of added fat for 42 d. The dietary lipid treatments were formulated with safflower oil and menhaden oil to provide the following ratios of (n-6)/(n-3) fatty acids: 23.8 (SMI), 9.8 (SMII), 2.6 (SMIII), and 1.2 (SMIV). Ex vivo PGE(2) production in liver homogenates and bone organ cultures (right femur and tibia) were significantly lower in rats fed diets with a lower dietary ratio of (n-6)/(n-3) fatty acids than in those fed diets with a higher dietary ratio. Regression analysis revealed a significant positive correlation between bone PGE(2) and the ratio of arachidonic acid (AA)/eicosapentaenoic acid (EPA), but significant negative correlations between bone formation rate and either the ratio of AA/EPA or PGE(2) in bone. Activities of serum alkaline phosphatase isoenzymes, including the bone-specific isoenzyme (BALP), were greater in rats fed a diet high in (n-3) or a low ratio of (n-6)/(n-3), further supporting the positive action of (n-3) fatty acids on bone formation. These results demonstrated that the dietary ratio of (n-6)/(n-3) modulates bone PGE(2) production and the activity of serum BALP in growing rats.

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The results of clinical and pulmonary functional evaluation of 24 cats with bronchopulmonary disease and 15 healthy cats are presented. Affected cats had historical evidence of excessive reflexes (coughing, sneezing); physical evidence of airway secretions (crackles), obstruction (wheezing), and increased tracheal sensitivity; radiographic evidence of bronchial and interstitial lung disease; and cytological evidence of airway inflammation or mucous secretions. Bacterial isolates from healthy and affected cats were predominantly Gram-negative rods, indicating that bronchi of cats are not always sterile and that normal flora should be considered in interpreting cultures from cats with suspected bronchopulmonary disease. Cats were grouped according t o relative disease severity based on scored historical, physical, and radiographic abnormalities. The mean (? standard deviation) baseline lung resistance measurement in healthy cats was 28.9 cm H,O/L/s (?6.2 cm H,O/L/s), whereas in mildly, ronchopulmonary disease in the cat represents a group B of poorly understood airway and alveolar space disorder^.'.^ Clinical signs are thought to be due, in part, to underlying airway obstruction. Factors contributing to the development of airway obstruction presumably include development of airway inflammation and mucosal edema, development of airway smooth muscle hypertrophy and constriction, and excessive production or retention of pulmonary secretions. Actual measurements of pulmonary function in cats with bronchopulmonary disease have not been available previously. We obtained pulmonary functional measurements from cats with naturally occurring disease and from clinically healthy cats in an attempt to better assess the presence and degree of airway obstruction in affected cats. Healthy cats were defined as subjects with no known historical or physical findings indicating respiratory disease. A complete clinical database (including historical, physical, and radiographic assessments) was obtained for all cats and also was used to quantify the relative clinical severity of respiratory disease. Measurements of baseline lung resistance (RL) and dynamic lung compliance (Cdyn) were obtained, and airway cytological and microbial culture data were collected. Whenever possible, evaluation also included IV administration of a bronchodilator (BD) to assess reversibility of the airway obstruction, or alternatively, an aerosolized bronchoprovocative challenge to assess the ease with which airway obstruction could be induced (ie, the degree of airway responsiveness [AR] present). Materials and Methods CatsTwenty-four cats with naturally occurring bronchopulmonary disease and 15 clinically healthy cats were evaluated in a cross-sectional study conducted over a 1-year period. The cats with bronchopulmonary disease included 21 cats presented or referred to the University of Illinois Veterinary Medicine Teaching Hospital (UIVMTH) for a variety of clinical signs suggestive of lower respiratory disease. One

Abstract. Aspiration of lytic bone lesions is an excellent diagnostic test in the initial evaluation of primary bone neoplasia. However, cytologically, it can be difficult to differentiate osteosarcoma (OSA) from other bone neoplasms, including fibrosarcoma, chondrosarcoma, synovial cell sarcoma, and plasma cell myeloma. The purpose of this study is to determine the sensitivity and specificity of alkaline phosphatase (ALP) staining to differentiate OSA from other tumors that express vimentin by immunocytochemistry or immunohistochemistry. ALP is a hydrolytic enzyme present in multiple tissues including liver, kidney, intestine, placenta, and bone. Hypothetically, neoplasms actively producing bone should be specifically positive for ALP staining. Unstained, cytologic specimens were incubated for 8-10 minutes with nitroblue tetrazolium chloride/5-bromo-4-chloro-3-indolyl phosphate toluidine salt-phosphatase substrate. A positive reaction stains the membrane of the cells gray to black. Samples were counterstained with a Romanowsky's stain to determine whether the sample was of representative cellularity. A total of 61 vimentin-positive neoplasms have been evaluated and confirmed histopathologically. Tumors that expressed vimentin and were positive for ALP included 33 OSAs, one multilobular tumor of bone, one amelanotic melanoma, and one chondrosarcoma. Tumors that expressed vimentin and were negative for ALP included chondrosarcomas (three of four), multiple fibrosarcomas, and multiple synovial cell sarcomas. The sensitivity is 100%, and the specificity is 89%. In conclusion, ALP appears to be a highly sensitive and fairly specific marker in the diagnosis of OSA.Key words: Alkaline phosphatase; bone; cytology; osteosarcoma.Osteosarcoma (OSA) is the most common primary bone tumor of dogs, accounting for 85% of reported skeletal malignancies. 4,14 Biologically, the tumor is locally aggressive, with a high metastatic rate. 16 The majority of OSAs are appendicular, 75% of which originate from the distal radius or proximal humerus. 7 Histopathologically, OSA is described as a malignant spindle cell tumor characterized by the production of an osteoid matrix by tumor cells. 16 The gold standard for diagnosis is considered biopsy with histopathologic evaluation. 7 Bone biopsy is an invasive procedure, often with a delayed diagnosis because of the decalcification process. In addition, bone biopsies can have complications, such as an increased risk of pathologic fracture at the biopsy site. Fine needle aspiration of lytic bone lesions is becoming more common in human medicine. 1,9,18 In one study, fine needle aspiration and cytology of bone tumors revealed a sensitivity of 86% and a specificity of 94.7%, with histopathology as the gold standard. 1 In veterinary medicine, aspiration of lytic lesions is gradually being used more frequently. In a recent study by Cohen et al., the overall sensitivity and specificity of cytology was evaluated. Although this study was not limited to bone, nine bone aspirations were evaluated, with...

Phenobarbital (PB) therapy is frequently associated with elevated serum alanine aminotransferase (ALT) and alkaline phosphatase (AP) activities in dogs without clinical signs of liver disease. The goal of this study was to determine if increased serum ALT and AP activities in clinically healthy PB-treated epileptic dogs are due to hepatic enzyme induction or to subclinical liver injury. Liver biopsies were obtained from 12 PB-treated dogs without clinical signs of liver disease but with elevated serum ALT and/or AP activities or both. Liver biopsies were obtained from eight healthy control dogs not receiving PB. Biopsies were evaluated histopathologically (all dogs) and liver homogenates were assayed for ALT (all dogs) and AP (six treated dogs, all controls) activities. As a positive control, liver cytochrome P4502B, an enzyme known to be induced by PB, was measured by benzyloxyresorufin-O-dealkylase activity and immunoblotting (five treated dogs, all controls). Serum AP isoenzyme analyses were performed. Results showed that ALT and AP activities in liver homogenates were not increased in treated dogs compared with controls, whereas the positive control for induction, CYP2B, was dramatically increased in treated dogs. Histopathological examination of liver biopsies revealed more severe and frequent abnormalities in treated dogs compared to controls, but similar types of abnormalities were found in both groups. Serum AP isoenzyme analyses in treated dogs demonstrated increased corticosteroid-induced and liver isoenzyme activities compared to controls. Results do not support induction of ALT or AP in the liver as the cause of elevated serum activities of these enzymes due to PB.

On the basis of this study, the DGGR method is considered adequate for assaying serum lipase activity in dogs. The high sensitivity of the DGGR assay suggests it may be a useful screening test for canine pancreatitis.

Sixty-one dogs with appendicular osteosarcoma were treated with amputation and chemotherapy of cisplatin and doxorubicin. Serum samples were obtained before and after treatment for determination of total alkaline phosphatase (TALP) activity as well as the activities of the constituent bone (BALP), liver (LALP), and corticosteroid-induced (CALP) isoenzymes. The relationship between alkaline phosphatase activities and survival was examined by Cox proportional hazards regression analysis and KaplanMeier log rank analysis. Mean activity of TALP, BALP, and LALP decreased significantly after treatment (P Ͻ .001). TALP and LALP activities before treatment were significantly correlated with survival (P ϭ .006 and .001, respectively). The correlation between BALP activity before treatment and survival approached significance (P ϭ .054). CALP activity and TALP, BALP, and LALP activities after treatment were not significantly correlated with survival. Dogs with normal pretreatment TALP and BALP activities survived significantly longer than dogs with increased pretreatment activities (P ϭ .001 and .003, respectively). Median survival times for dogs with normal or increased TALP activities before treatment were 12.5 and 5.5 months, respectively; and median survival times for dogs with normal or increased BALP activities before treatment were 16.6 and 9.5 months, respectively. In the design of future clinical trials involving dogs with osteosarcoma, consideration should be given to stratifying the randomization according to alkaline phosphatase activity. In addition, alkaline phosphatase activity should be a factor considered by clinicians attempting to tailor the aggressiveness of adjuvant chemotherapy to the needs of individual patients or owners.

Serum and urinary assays of bone markers provide a noninvasive alternative to bone biopsy in the study of bone metabolism in humans. Many of the commercial assays that were originally developed for use in humans have been shown to cross-react in dogs, and it should therefore be possible to use these assays to study bone remodeling in dogs. The interpretation of bone marker data in humans is hampered by extensive inter- and intra-subject variability. The specific aim of this study was therefore to determine the extent of biological variability in bone markers in dogs. Serum and urine samples were collected every 4 hours over a 24-hour period (short-term study), and every week over a 12-week period (long-term study). Serum bone-specific alkaline phosphatase (BALP) and urinary deoxypyridinoline (Dpd) and N-terminal telopeptide of collagen (NTx) were measured with commercial enzyme immunoassays. Serum osteocalcin (OC) and carboxyterminal crosslinked telopeptide of type I collagen (ICTP) were measured with commercial radioimmunoassays. In the short-term study, statistically significant diurnal rhythms were identified for OC, BALP, ICTP, and Dpd. No clear rhythm was evident for NTx. There was no evidence of statistically significant long-term variability in marker excretion over the 12 weeks. Our findings confirm the utility of these assays in dogs. However, as in humans, care must be taken to ensure that specimens are collected at a consistent time of day. Moreover, given the inherent variability in marker excretion in individual animals, the most appropriate use for these assays is as a screening tool for cohort studies, rather than as a diagnostic or prognostic tool in the individual animal.