Comparison of a commercially available veterinary digital refractometer to analogue refractometer and laboratory chemistry analyzer in the evaluation of canine serum total protein.

OBJECTIVE: To assess the agreement between measurements of total protein (TP) concentrations in canine serum samples between a commercially available veterinary digital refractometer (DR), an analog handheld refractometer (AR), and a laboratory-based chemistry analyzer (LAB). An additional objective was to assess the effects of various potential interferents (ie, hyperbilirubinemia, increased BUN, hyperglycemia, hemolysis, and lipemia) on DR measurements. SAMPLE: 108 canine serum samples. PROCEDURES: Serum samples were measured in duplicate on the DR, which reported TP concentration, assessed via optical reflectance and critical angle measurement. These serum samples were also assessed on the AR and LAB for comparison. Serum samples with grossly visible lipemia, hemolysis, and icterus were noted. Medical records were retrospectively assessed to determine concentrations of BUN, glucose, and bilirubin. RESULTS: Method comparisons among the various data generated by the analyzers were completed using linear regression, Bland Altman, and calculation of intraclass coefficients. Mean bias between DRTP and LABTP in samples without potential interferents was 0.54 g/dL with 95% limits of agreement of -0.17 to 1.27 g/dL. One-third of DRTP samples without potential interferents had > 10% difference from their LABTP comparison. Interferents, particularly marked hyperglycemia, can result in inaccurate measurements on the DR. CLINICAL RELEVANCE: There was a statistically significant difference between DRTP and LABTP measurements. TP measurements in samples with any potential interferent, particularly hyperglycemia, should be assessed cautiously on DR and AR.

Effects of potential confounding variables on accuracy of a commercially available veterinary point-of-care hematocrit meter in the evaluation of blood samples from dogs and cats.

OBJECTIVE: To assess the agreement in measurements of Hct values and hemoglobin (Hgb) concentrations in blood samples from dogs and cats between a commercially available veterinary point-of-care (POC) Hct meter and a laboratory-based (LAB) analyzer and to determine the effects of various conditions (ie, lipemia, hyperbilirubinemia, hemolysis, autoagglutination, and reticulocytosis) on the accuracy of the POC meter. SAMPLES: Blood samples from 86 dogs and 18 cats. PROCEDURES: Blood samples were run in duplicate on the POC meter, which reported Hgb concentration, measured via optical reflectance, and a calculated Hct value. The POC meter results were compared with results from a LAB analyzer. Blood samples with grossly visible lipemia, icterus, hemolysis, and autoagglutination were noted. RESULTS: Mean ± SD values for LAB Hct were 33.9 ± 15.73% (range, 3.9% to 75.8%), and for LAB Hgb were 11.2 ± 5.4 g/dL (range, 1 to 24.6 g/dL). Mean bias between POC Hct and LAB Hct values was -1.8% with 95% limits of agreement (LOAs) of -11.1% to 7.5% and between POC Hgb and LAB Hgb concentrations was -0.5 g/dL with 95% LOAs of -3.8 to 2.8 g/dL. There was no influence of lipemia (14 samples), icterus (23), autoagglutination (14), hemolysis (12), or high reticulocyte count (15) on the accuracy of the POC meter. The POC meter was unable to read 13 blood samples; 9 had a LAB Hct ≤ 12%, and 4 had a LAB Hct concentration between 13% and 17%. CONCLUSIONS AND CLINICAL RELEVANCE: Overall, measurements from the POC meter had good agreement with those from the LAB analyzer. However, LOAs were fairly wide, indicating that there may be clinically important differences between measurements from the POC meter and LAB analyzer.

A comparison of body and organ weights, physiologic parameters, and pathologic changes in target organs of rats given combinations of exercise, anabolic hormone, and protein supplementation.

This study was engineered to closely mimic the training protocol of a competitive athlete using repetitive exercise sessions, dietary protein supplementation, and anabolic steroids. The length of the study was 37 days. Thirty-four Sprague Dawley male rats Crl:CD(SD)BR in the weight range of 150 to 175 grams were used. These were randomly divided into four exercise groups, varying protein consumption and anabolic hormone administration. Eight nonexercised control rats were kept separate from the study to act as a comparison for organ weight, hematology, and serology. Exercise consisted of a 30 minute swim three times a week. Parameters recorded were total body weight and percent gain, wet and dry muscle weight of the isolated anterior tibialis, weights of designated organs, hematologic profiles, and serum chemistries including triglycerides, high density and low density lipids. Histopathology of known "target organs" was performed and bone marrow aspirates were taken. Body weights of rats given anabolic steroid, protein supplement, and exercise were the lowest of all groups. Testicular weight was significantly decreased in the anabolic groups. Anabolic groups had the lowest hematocrits of the exercised groups. All serology values were within normal ranges and no pathologic changes were seen in any of the tissues taken from specific "target organs."

Effect of a sustained release formulation of diltiazem on the development of atherosclerosis in cholesterol-fed rabbits.

Cholesterol-fed rabbits were used to test potential anti-atherosclerotic effects of diltiazem, a calcium antagonist of the benzothiazepine type. Two groups of 7 rabbits each were fed standard laboratory chow supplemented with 1% cholesterol. One group received a 60 mg sustained release diltiazem capsule twice a day and the other group received a placebo capsule twice a day. A third group of control animals were fed an unmodified basal diet under conditions exactly the same as the experimental groups. All groups were studied over a period of 16 weeks. The cholesterol-fed animals showed a marked increase in plasma total cholesterol which was not significantly different for the diltiazem and placebo groups. Plasma calcium levels, blood pressure, and heart rate were also unchanged from the control animals. In the diltiazem-treated animals, 47.5 +/- 10.5% of the aortae showed atherosclerotic lesions; the value for the placebo group was 43.1 +/- 8.1%. Similar results were obtained for the coronary arteries. These results show that diltiazem treatment in the doses employed in this study had no effect on the reduction of atherosclerosis in this animal model.

Effect of coadministration of phenobarbital sodium on N-nitrosodiethylamine-induced gamma-glutamyltransferase-positive foci and hepatocellular carcinoma in rats.

The effect of concurrent administration of phenobarbital on the hepatocarcinogenicity of N-nitrosodiethylamine (diethylnitrosamine; DENA) in rats was investigated by determination of the incidence of gamma-glutamyltransferase (gamma-glutamyltranspeptidase) (GGT)-positive foci and liver tumors. Male outbred Sprague-Dawley rats received either a weekly oral dose of DENA (0.08 mol/kg), phenobarbital sodium (500 ppm) in their drinking water, or DENA and phenobarbital sodium concurrently. After 16 weeks, only the animals treated concurrently with DENA and phenobarbital sodium had GGT-positive foci (3.65 foci/cm2). At 30 weeks, the group treated with DENA and phenobarbital sodium exhibited more foci (23.6 foci/cm2) compared to the group that received only DENA (3.08 foci/cm2). The average size of foci in both of the DENA-treated groups was the same. The tumors in the group that received DENA plus phenobarbital sodium showed a greater incidence of GGT activity compared to the tumors in the DENA group. Under the conditions of this study the incidence of GGT-positive foci did not predict the incidence of hepatocellular carcinomas.

Effects of strain, sex, route of administration and partial hepatectomy on the induction by chemical carcinogens of gamma-glutamyltranspeptidase foci in rat liver.

The incidence of gamma-glutamyltranspeptidase (GGT)-positive foci induced by 0.3 mmol/kg diethylnitrosamine (DENA) followed by promotion with 500 ppm sodium phenobarbital in drinking water and was the same in Fischer 344, Sprague-Dawley and Wistar-Lewis rats. There was no difference in the level of GGT-foci initiated by DENA, 7,12-dimethylbenz[a]-anthracene (DMBA), or 1,2-dimethylhydrazine (DMH) followed by promotion with phenobarbital with respect to sex or route of administration including gavage and intraperitoneal injection. Maximal stimulation by partial hepatectomy of DENA initiation of GGT-foci occurred when the DENA was administered 18 h after the operation. Our results indicate that the optimal protocol for the rat liver foci assay consists of using partial hepatectomized rats of 1 of the 3 strains and of either sex. The test substance should be administered by either gavage or intraperitoneal injection so that maximal DNA binding coincides with the maximal rate of DNA replication resulting from partial hepatectomy.

Effect of dibutylnitrosamine and saccharin on glutamyl transpeptidase-positive foci and liver cancer.

Consistent with the proposed precursor relationship of GGTase-positive foci to hepatocarcinogenesis, the induction of foci by DBN was associated with the induction of hyperplastic nodules and hepatocellular carcinoma and the concurrent administration of sodium saccharin in the diet with DBN in the drinking water increased the tumorigenic response in the liver to DBN.

Characteristics of 85 pediatric tumors heterotransplanted into nude mice.

81 primary pediatric tumors and 4 tumor lines were heterotransplanted into nude mice with an overall success rate of 38.3%. There was variability in success between tumor types. Bone sarcomas were highly successful while brain, lymphoid, and benign tumors in general did poorly. With increasing passage lag times decreased but actual growth rates in general did not change. Results suggested that tumors obtained prior to therapy which grew in nude mice were more likely to recur in the patient. During the observation period 7 spontaneous mouse tumors developed, distinguished from human tumors by histology, cytogenetics, and isoenzyme studies.

Initiation/promotion assay for chemical carcinogens in rat liver.

A short-term initiation/promotion bioassay has been developed in rat liver using putative preneoplastic foci as the endpoint for the detection of chemical carcinogens. The two protocols of the bioassay used in this study were varied according to the time 2/3 partial hepatectomy was performed in relation to when the initiator or test substance was given. After 7 weeks of promotion with phenobarbital in the drinking water, the rats were killed and the liver was sectioned, stained and scored for gamma-glutamyl transpeptidase (GGTase)-positive foci. The appearance of GGTase-positive foci was taken as an indication of initiation of carcinogenesis by the chemical. Acetylaminofluorene (AAF), aflatoxin B1 (AFB1), benzo(a)pyrene (BaP), diethylnitrosamine (DENA), 7,12-dimethylbenzo(a)anthracene, (DMBA), dimethylhydrazine (DMH), dimethylnitrosamine (DMN) and urethane were positive in the assay, while benzene and N-methyl-N-nitro-N-nitrosoguanidine (MNNG) were negative. Phenobarbital promoted the response of AAF, AFB1, BaP, DENA, DMBA, DMH and DMN. Partial hepatectomy 24 h prior to initiation increased the response of AAF, BaP, DENA, DMBA and DMH. The initiation/promotion assay in rat liver which includes (1) partial hepatectomy at 24 h prior to administering the test chemical; (2) phenobarbital promotion, and (3) GGTase-positive foci as an indication of carcinogenic activity: appears to be sensitive to a wide variety of chemical carcinogens.

Promotion by polychlorinated biphenyls of enzyme-altered foci in rat liver.

Aroclor 1254 is a complex mixture of polychlorinated biphenyls (PCB) that upon prolonged administration has been reported to produce hepatic tumors in mice and rats. The ability of Aroclor 1254 to promote enzyme-altered foci was determined in an initiation/promotion bioassay in rat liver. Initiation was accomplished in rats that received a 2/3 partial hepatectomy followed in 24 h by diethylnitrosamine (DENA). Aroclor 1254 was administered to each rat 7, 28 and 49 days after the DENA and some of the rats were killed 21 days after each dose of Aroclor. The liver of rats that received Aroclor 1254 on either day 7 or on day 7 and 28 contained an increased incidence of gamma-glutamyltranspeptidase (GGTase)-positive foci compared to partial hepatectomized and DENA treated rats given tricaprylin (the solvent for Aroclor 1254). Therefore, Aroclor 1254 was demonstrated to enhance the appearance of enzyme-altered foci after only a single oral dose.

Sex difference in enhancement of GGTase-positive foci by hexachlorobenzene and lindane in rat liver.

The ability of hexachlorobenzene and lindane in diethylnitrosamine (DENA) pretreated rats to enhance the incidence of gamma-glutamyltranspeptidase (GGTase)-positive foci was determined. In rats that received either DENA followed by a basal agar diet or hexachlorobenzene or lindane without prior administration of DENA, the incidence of GGTase-positive foci was negligible. When hexachlorobenzene or lindane were administered in the diet to rats that previously received a 2/3 partial hepatectomy prior to the DENA. The results suggest that hepatocarcinogenicity of hexachlorobenzene and lindane results from tumor promotion.

Polyserositis and arthritis due to Escherichia coli in gnotobiotic pigs.

Forty gnotobiotic pigs from six litters were exposed orally to Escherichia coli 083:K.:NM at 69 to 148 hours of age, while 17 pigs from the same litters served as unexposed controls. Clinical signs of infection included fever, anorexia, diarrhea, lameness, and reluctance to move.Eighty-four percent of the exposed pigs in four litters died, while only 13% in two litters died. Gross and microscopic lesions included serofibrinous to fibrinopurulent polyserositis in 96% of the exposed pigs in four litters and 33% of the exposed pigs in two litters. A few pigs had gross and/or microscopic lesions of arthritis. Escherichia coli was routinely isolated from the serous and synovial cavities of infected pigs.Anti-hog cholera serum administered orally as a colostrum substitute gave partial protection against E. coli infection.