Influenza A plasma and serum virus antibody detection comparison in dogs using blocking enzyme-linked immunosorbent assay.

BACKGROUND AND AIM: The influenza A virus (IAV) is an important zoonotic pathogen with infections also reported in dogs. IAV infections can be detected through the presence of antibodies using the enzyme-linked immunosorbent assay (ELISA). Serum is the only standard sample source; however, there is no information on the availability of other sample sources for IAV antibody detection in dogs. Compared with serum, plasma is more widely employed in most animal hospitals. The object of this study is to investigate whether plasma collected in ethylenediaminetetraacetic acid (EDTA) tubes (EDTA plasma) or heparin tubes (heparin plasma) could be used in the ELISA protocol instead of serum for IAV antibody detection in dogs. MATERIALS AND METHODS: Totally, 82 matched EDTA plasma and serum sample pairs and 79 matched heparin plasma and serum sample pairs were employed using blocking enzyme-linked immunosorbent assay (bELISA). The agreement and correlation between the plasma (EDTA or heparin plasma) and serum were assessed using the agreement index kappa (kD) calculation and Pearson correlation coefficient, respectively. RESULTS: The agreement index kD of EDTA plasma and serum was 1.0, and that of heparin plasma and serum was 0.85. The Pearson correlation coefficient of EDTA plasma and serum was 0.87 (p<0.01), and that of heparin plasma and serum was 0.82 (p<0.01). CONCLUSION: The results proved that plasma, especially EDTA plasma, could be substituted for serum in the bELISA test. This might greatly expand the clinical applicability of IAV antibody detection in dogs.

A morphometric quantitation of developmental changes in elastic fibers in rat lung parenchyma: variability with lung region and postnatal age.

Elastin has long been thought to play a pivotal role in alveolar septal development by providing the structural framework around which new alveoli develop in the immature lung. This theory was derived from observations that the dramatic increase in lung elastin and alveolar septal development occurred during the same time period, days 4 to 13 in the rat. Using stereologic techniques, we evaluated volume density of respiratory tissue in parenchyma and total length of parenchymal elastic fibers in the lungs of neonatal rats ranging in age from 4 to 26 days. Lung tissue was obtained from each of the four right lung lobes and from the upper, middle, and lower regions of the left lung. When changes in these two parameters in the lung as a whole were considered by averaging values for each of the seven regions, a continuous increase was observed in both the volume of parenchymal tissue in parenchyma and the total length of elastic fibers from days 4 to 22. A significant correlation was found between the volume of respiratory tissue in parenchyma and the length of parenchymal elastic fibers from days 4 to 26, supporting the existing theory that a causal relationship exists between these two parameters. A comparison of the ratios of elastic fiber length to volume density of respiratory tissue in parenchyma (Lv/Vrp) from each of the seven lung regions sampled indicated a significant variability in Lv/Vrp within different regions of the same lung. In addition, the effects of postnatal age and lung region on Lv/Vrp were interdependent; the lung regions that differed with respect to the length density of elastic fibers varied with postnatal age.(ABSTRACT TRUNCATED AT 250 WORDS)

Endurance training reduces the magnitude of exercise-induced hyperammonemia in humans.

The purpose of this study was to determine the influence of endurance-type exercise training on alterations of the ammonia content of blood in exercising humans. Seven females and four males trained 6 days/wk for 7 wk alternating days of continuous cycling (40 min) and interval running (five 5-min bouts). The NH3 content of blood was determined before and during cycle ergometer (CE) exercise (4 min) at power outputs (PO) of 119, 172, and 241 W pretraining and of 163, 230, and 271 W posttraining. These PO for each occasion represent relative work loads of approximately 65, 90, and 115% of peak CE maximum O2 uptake (PCE VO2), respectively. Training increased (P less than 0.05) PCE VO2 approximately 32% (2.72 +/- 0.25 to 3.56 +/- 0.29 l/min or 38.5 +/- 1.9 to 51.2 +/- 2.3 ml X kg-1 X min-1). Both pre- and posttraining the NH3 content of blood increased (P less than 0.05) with increasing intensity of exercise. Training did not influence the measure of these responses during exercise at the same relative intensity. During exercise at the same absolute PO, approximately 168 or 235 W, however, increases in blood NH3 were less (P less than 0.05) after training. The results indicate that the magnitude of increase in blood NH3 during exercise is determined by the energy requirement of the absolute work load, relative to an individual's aerobic power.

Effects of pulmonary metabolites of prostaglandins E2 and F2alpha on guinea-pig respiratory tract.

The effects of three pulmonary metabolites of prostaglandins E2 and F2alpha on the guinea-pig tracheal muscle in vitro and on lung resistance in vivo were investigated. Prostaglandin F2alpha, 13,14-dihydro PGF2alpha and 13,14-dihydro 15-oxo PGF2alpha produced contractions on the tracheal muscle in vitro. 15-oxo PGF2alpha relaxed some tracheal preparations but stimulated others, the stimulant action having a threshold dose range some 10-25 times lower than the relaxant doses. Prostaglandin F2alpha and 13,14-dihydro PGF2alpha increased lung resistance in anaesthetized guinea-pigs. Prostaglandin E2 and its three pulmonary metabolites produced relaxation of guinea pig trachea in vitro and decreased lung resistance in vivo. All three metabolites were less active than PGE2 in both the systems. The in vitro effects of PGF2alpha and its metabolites were selectively blocked by polyphloretin phosphate.

Mechanism of relaxant action of prostaglandin F2alpha on the guinea-pig isolated trachea.

Prostaglandin F2alpha consistently produced a dose-related triphasic response in guinea-pig isolated tracheal chain preparations. The response consisted of an initial transient contraction followed by a transient relaxation, followed by a further contraction. The relaxant action was not due to adrenergic or histaminergic transmission, but might be due to a PG-like material released by the PGF 2alpha-induced contraction.