Development of a polymerase chain reaction-based method to identify species-specific components in dog food

OBJECTIVES: To determine whether there is a relationship between species-specific mitochondrial DNA (mtDNA), especially canine and feline mtDNA, and detectable amounts of pentobarbital in previously analyzed dog food samples. SAMPLE POPULATION: 31 dog food samples previously analyzed for pentobarbital (limit of detection, 1 microg/kg). PROCEDURE: Polymerase chain reaction (PCR) analysis was performed on dog food samples by use of PCR primers specific for either canine, feline, equine, bovine, porcine, ovine, or poultry mtDNA. RESULTS: PCR amplicons specific for feline or canine mtDNA at a 0.007% (70 microg/g [wt/wt basis]) or 0.0007% (7 microg/g) level, respectively, were not found in the 31 dog food samples. Most of the 31 dog food samples had a PCR amplicon on PCR analysis when a PCR primer set capable of simultaneously detecting mtDNA of cows, pigs, sheep, goats, deer, elk, and horses was used. Results of PCR analysis by use of primers specific for bovine, swine, sheep and goat, or horse mtDNA revealed amplicons specific for bovine or swine mtDNA only in 27 of the 31 samples. Analysis of the remaining 4 samples failed to yield amplicons for any mammalian mtDNA. Pentobarbital was detected in 2 of these 4 samples. Results of PCR analysis correlated with the stated ingredient list for most, but not all samples. CONCLUSIONS AND CLINICAL RELEVANCE: Because canine and feline mtDNA were not found in a set of retail dog food samples, these results indicate that the source of pentobarbital in dog food is something other than proteins from rendered pet remains.     

The effect of strenuous exercise on mRNA concentrations of interleukin-12, interferon-gamma and interleukin-4 in equine pulmonary and peripheral blood mononuclear cells

The effect of strenuous exercise on the mRNA concentrations of interleukin-12p35 subunit (IL-12p35), interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in equine pulmonary and peripheral blood mononuclear cells (PBMCs) was investigated. We hypothesized that strenuous exercise would suppress the expression of IL-12p35, IFN-gamma and augment the expression of IL-4. Eleven horses were randomly divided into two groups, a stall-confined control group (n=5) and an exercise-conditioned treatment group (n=6). Bronchoalveolar and PBMCs were obtained from horses in the treatment group prior to the commencement of a 9-week conditioning program and 24h after the completion of a maximum exercise test conducted in week 12. Samples were obtained simultaneously from control horses. Differential counts were performed on the bronchoalveolar lavage cells. Real-time PCR was performed on the pulmonary and PBMCs to quantitate cytokine expression using equine-specific primers and Taqman probes. Target gene expression was normalized to 18s rRNA expression. With the exception of IL-4 in the BALF cells, mRNA for the three cytokines was detected in the mononuclear cells from all horses at both sampling times. There were no significant differences in the cytokine mRNA concentrations between the two groups of horses at either of the sampling times. These findings demonstrate that strenuous treadmill exercise does not exert a deleterious effect on gene expression for IL-12p35, IFN-gamma or IL-4 when assessed in horses 24h following the intense physical activity.     

Portal streamlining as a cause of nonuniform hepatic distribution of sodium pertechnetate during per-rectal portal scintigraphy in the dog

The purpose of this study was to evaluate nonuniform patterns of vascular distribution of pertechnetate in the dog during per-rectal portal scintigraphy. Ninety-two studies were reviewed retrospectively to document the patterns of radionuclide distribution. Forty-five studies were classified as normal and 47 were classified as diagnostic for a macrovascular portosystemic shunt. In these dogs, shunt fractions were calculated and compared using a t-test. In dogs with sufficient liver radioactivity for evaluation, the study was classified as having uniform, dorsal, central, or ventral radiopharmaceutical distributions. There were 51 animals (45 normal and six dogs with low-magnitude portosystemic shunts) with sufficient liver activity to assess the radionuclide distribution within the liver. A one-way ANOVA was used to compare shunt fractions between each of the distribution patterns. Two dogs were anesthetized and selective portovenograms were performed. Portovenograms were compared with the scintigraphic images to correlate the vascular distribution of the right, central, and left divisional branches of the portal vein. The shunt fraction in the 45 normal dogs was significantly lower than in the dogs with portosystemic shunts (5.7% +/- 4.8% vs. 78.6% +/- 20.0% (mean +/- SD), P < 0.001). Of the 51 dogs with sufficient liver activity to classify the pattern of distribution, there were 15/51 (31.4%) with uniform radionuclide distribution, 10/51 (19.6%) with focal dorsal distribution, 15/51 (29.4%) with focal ventral distribution, and 10/51 (19.6%) with focal central distribution. There was no significant difference in the shunt fractions between the groups. There were six dogs diagnosed with low-magnitude portosystemic shunt with sufficient liver radioactivity to categorize the vascular distribution of the radionuclide within the liver. Of these six dogs, two had focal dorsal distribution, one had focal central, one had focal ventral and two had uniform distribution. Focal dorsal distribution could result from streamlining of the radionuclide into the right divisional branch of the portal vein. Focal ventral distribution could result from streamlining the radionuclide into the left divisional branch of the portal vein. Focal central distribution could result from streamlining the radionuclide into the central divisional branch of the portal vein.     

VALIDATION OF DECONVOLUTIONAL ANALYSIS FOR THE MEASUREMENT OF HEPATIC FUNCTION IN DOGS WITH TOXIC-INDUCED LIVER DISEASE

The extraction of the hepatobiliary radiopharmaceutical ^99mTc-mebrofenin ( Choletec ) by the liver can be used to evaluate the severity of hepatocellular disease. The hepatic parenchymal cells extract mebrofenin from the blood by the same active transport mechanism as bilirubin. The ability of the liver to extract ^99mTc-membrofenin is a measure of hepatic parenchymal cell function. In this study, we induced hepatocellular disease by administration of a hepatotoxic drug and compared a direct method of determining the hepatic extraction of ^99mTc-membrofenin to hepatic extraction fraction derived from deconvolutional analysis. We also compared both methods of calculating the hepatic extraction of ^99mTc-membrofenin to liver histopathology. Hepatic extraction fraction derived from deconvolutional analysis correlated very well to the direct measurement technique (R=0.922, p<0.001). Both methods of determining hepatic extraction correlated well to quantitative histopathology, having the same correlation coefficient and p values. (R=-0.833, p=0.003). As the hepatic extraction ^99mTc-membrofenin decreased, the severity of the histopathologic lesions of the liver increased in a linear fashion. There was a significant correlation of the hepatic excretion T_1/2 to quantititative histopathology (R=0.949, p<0.001). The hepatic excretion T_1/2 increased as the severity of the histopathologic lesions of the liver increased. Hepatic extraction (HEF) and excretion of ^99mTc-membrofenin are good predictors of the severity of hepatocellular damage in toxic induced liver disease. This study helps validate the premise that HEF derived from deconvolutional analysis ois a good predictor of the actual first pass hepatic extraction of ^99mTc-membrofenin.     

Selection for increased incidence of double‐yolked eggs in white leghorn chickens

1. Eleven generations of selection on two White Leghorn lines resulted in birds which, on the average, laid at least 30 double‐yolked eggs to 40 weeks of age.

2. The total number of yolks laid to 40 weeks was comparable with that of a control line selected for high egg number.

3. At peak production an F₁ cross of the two inbred lines laid 140 yolks per hundred hens per day.

4. Double‐yolk selected lines when crossed produced hens with a 20% increased body weight.

5. By the 10th and 11th generations the incidence of eggs with three or four yolks was increasing.     

Pesticide residues in the total diet in Canada. III—1971

Foods, representing an average Canadian diet, were cooked, grouped by type of product and made into composites which were then analysed for organochlorine and organophosphorus pesticides and arsenic. The amounts found were at a consistently low level and would contribute approx. 22 μg total pesticide residues and 25 μg arsenic/person/day.     

Genetic changes in quantity and composition of vegetable oils

Summary The oil contents of single kernels of corn can be determined by wideline nuclear magnetic resonance spectroscopy. Since this analytical procedure does not alter seed composition or viability, it could accelerate the development of crops having higher oil contents. A highly significant correlation was found between the oil contents of single kernels of corn and their progeny ears. This indicates that single-kernel differences in oil content are heritable. The importance of this development in terms of the increasing world-wide demand for polyunsaturated oils is discussed.

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Zusammenfassung Der Öl-Gehalt einzelner Maiskörner kann durch kernmagnetische Resonanz-Spektroskopie festgestellt werden. Da dieses analytische Verfahren weder die Samenzusammensetzung noch die Lebensfähigkeit des Samens ändert, könnte sie dazu benutzt werden, die Entwicklung von Maisbeständen mit höherem Ölgehalt zu beschleunigen. Es wurde eine höchst beachtliche Korrelation zwischen dem Ölgehalt der einzelnen Kerne und dem der daraus entstehenden Kerne gefunden. Dies weist darauf hin, daß Einzel-Kern-Unterschiede im Ölgehalt vererbbar sind. Die Bedeutung dieser Entwicklung in Bezug auf die weltweite Nachfrage nach mehrfach ungesättigten Ölen wird besprochen.

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Résumé La quantité d'huile contenue dans les grains de maïs isolés peut être déterminée par la spectroscopie à résonance magnétique nucléaire à grande amplitude. Comme ce procédé ne cause aucune altération de la composition ou de la viabilité de la semence il pourrait accélérer la production de récoltes a rendement d'huile élevé. Une corrélation très étroite a été établie entre la quantité d'huile contenue dans les grains individuels et celle contenue dans leur progéniture. Ceci indique que la difference entre les quantités d'huile contenues dans deux grains individuels peut-être héritée. Cet article traite de l'importance de cette application scientifique en liaison avec la demande croissante d'huiles polyinsaturées dans le monde entier.

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with 4 figs.

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Paper presented at 6th International Congress of Nutrition, Edinburgh, August 9–15, 1963.     

Comparison of a human portable glucometer and an automated chemistry analyzer for measurement of blood glucose concentration in pet ferrets (Mustela putorius furo)

This study compared blood glucose concentrations measured with a portable blood glucometer and a validated laboratory analyzer in venous blood samples of 20 pet ferrets (Mustela putorius furo). Correlation and agreement were evaluated with a Bland-Altman plot method and Lin’s concordance correlation coefficient. Blood glucose concentrations measured with the laboratory analyzer and the glucometer ranged from 1.9 to 8.6 mmol/L and from 0.9 to 9.2 mmol/L, respectively. The glucometer had a poor agreement and correlation with the laboratory analyzer (bias, −0.13 mmol/L; level of agreement, −2.0 to 3.6 mmol/L, concordance correlation coefficient 0.665). The relative sensitivity and specificity of the portable blood glucometer for detection of hypoglycemia were 100% (95% CI: 66% to 100%) and 50% (95% CI: 20% to 80%), respectively. Positive and negative predictive values were 67% (95% CI: 39% to 87%) and 100% (95% CI: 46% to 100%), respectively. Based on these results, clinicians are advised to be cautious when considering the results from this handheld glucometer in pet ferrets, and blood glucose concentrations should be determined with a laboratory analyzer validated for this species.     

Strong association of de novo copy number mutations with autism

We tested the hypothesis that de novo copy number variation (CNV) is associated with autism spectrum disorders (ASDs). We performed comparative genomic hybridization (CGH) on the genomic DNA of patients and unaffected subjects to detect copy number variants not present in their respective parents. Candidate genomic regions were validated by higher-resolution CGH, paternity testing, cytogenetics, fluorescence in situ hybridization, and microsatellite genotyping. Confirmed de novo CNVs were significantly associated with autism (P = 0.0005). Such CNVs were identified in 12 out of 118 (10%) of patients with sporadic autism, in 2 out of 77 (3%) of patients with an affected first-degree relative, and in 2 out of 196 (1%) of controls. Most de novo CNVs were smaller than microscopic resolution. Affected genomic regions were highly heterogeneous and included mutations of single genes. These findings establish de novo germline mutation as a more significant risk factor for ASD than previously recognized.