Cellular injury and lipid peroxidation induced by hexavalent chromium in isolated rat hepatocytes

In order to elucidate the relationship between cellular injury and lipid peroxidation induced by hexavalent chromium (CrVI), isolated rat hepatocytes treated with any one of scavengers of active oxygen species, antioxidants or antichromium agent were incubated with K2Cr2O7 as CrVI (1 mM Cr). After the incubation, the development of lipid peroxidation was determined as thiobarbituric acid (TBA)-reacting materials in total lipid extracts from the incubated hepatocytes. Cellular injury was observed as a leakage of lactate dehydrogenase (LDH) from hepatocytes into incubation medium. The contents of reduced glutathione (GSH) in hepatocytes were also assessed. Results obtained were as follows: (1) CrVI facilitated lipid peroxidation in isolated hepatocytes after 20 min of incubation. On the other hand, the cellular injury induced by CrVI was barely observed even after 60 min of incubation. (2) The CrVI-induced lipid peroxidation was inhibited by catalase and mannitol as scavengers of active oxygen species, or N,N'-diphenyl-p-phenylenediamine and alpha-tocopherol as antioxidants. However the cytotoxicity of CrVI could not be prevented by these chemicals. (3) CrVI depleted the contents of intracellular GSH and diminished the activities of glutathione reductase (GR) and glutathione-S-transferase (GST) except glutathione peroxidase. (4) The scavengers of active oxygen species and the antioxidants could not prevent the depletion of intracellular GSH induced by CrVI. (6) Ascorbic acid, antichromium agent, prevented all of the lipid peroxidation, the cellular injury and intracellular GSH depletion induced by CrVI.(ABSTRACT TRUNCATED AT 250 WORDS)     

Competitive enzyme-linked immunosorbent assay for the detection of the antibodies specific to akabane virus.

A competitive enzyme-linked immunosorbent assay (C-ELISA) using neutralizing monoclonal antibodies (MAbs) against Akabane virus (AKAV) was developed to detect antibodies to AKAV in cattle sera. The performance of the test using 7 different competitor MAbs was evaluated in sequential serum samples and sera from cattle infected with various bovine arboviruses. The dynamics of the antibody response expressed by percentage of inhibition (PI) in C-ELISA coincided with those of neutralizing antibody titers in sequential serum samples from 2 cattle experimentally infected with AKAV. The value of PI in C-ELISA for convalescent sera from cattle infected with arboviruses correlated with the neutralizing antibody titer to AKAV but was unaffected by the antibodies to other arboviruses. In the validation experiment of C-ELISA using 286 bovine sera previously examined for the AKAV antibody by serum neutralization (SN) test, the relative specificity of C-ELISA was more than 98%, whereas the relative sensitivities of individual MAbs ranged from 49% to 82.2%. Overall agreement between C-ELISA and the SN test varied from 72% to 90% depending on the MAb. These results suggest that the C-ELISA is acceptable as a rapid and specific method for detecting antibodies to AKAV and is a potential alternative to the SN test.     

Myofibrillar proteolysis in chick muscle cell cultures during heat stress

The effect of heat stress on protein oxidation and myofibrillar proteolysis in chick myotubes was investigated. Myotubes were incubated at 37 or 41°C for 6 and 24 h. Protein carbonyl content, as an index of protein oxidation, increased more at 41°C than at 37°C for 6 and 24 h incubations. N^τ‐methylhistidine release as an index of myofibrillar proteolysis also increased more at 41°C than at 37°C for 6 and 24 h incubations. Proteasome activity also increased more under those same conditions. Calpain and cathepsin D but not B + L activities showed a greater increase at 41°C than at 37°C for 24 but not the 6 h incubation. These results indicate that heat stress increases protein oxidation and proteasome activity, resulting in an increase in myofibrillar proteolysis for short‐term incubation and, for long‐term incubation, it increases calpain, proteasome and cathepsin D activities, finally accelerating myofibrillar proteolysis in chick myotubes.     

Mesh-like vascular changes in copper deficiency-induced rat cardiomyopathy

The pathological effects of copper deficiency (COD) are well known. However, the pathogenesis of cardiomyopathy resulting from COD remains unclear. In this study, aimed to elucidate the pathogenesis of COD-induced cardiomyopathy by examining the morphology of the cardiovascular system in copper-deficient rats using histopathology, immunohistochemistry, and scanning and transmission electron microscopy. Changes detected in the myocardium and interstitium were consistent with those reported for COD. Morphological changes included mesh-like changes in the capillary endothelial cells that appear to be a novel finding in COD-induced cardiomyopathy. These changes are hypothesized to result from abnormal vascular remodeling following damage to the basement membrane and due to the mechanical effects of myocardial contractions. Although cardiomyopathy may be associated with microcirculatory disorders arising from these lesions, further investigations are necessary to demonstrate a causal relationship between the pathogenesis of cardiomyopathy and the contribution of these lesions to disease progression.     

Time-course comparison of pulmonary inflammation induced by intratracheal instillation of four different nickel oxide nanoparticles in male Fischer rats

Occupational exposure to nickel oxide (NiO) is an important cause of respiratory tract cancer. Toxicity is known to be associated with the dissociated component, i.e. nickel (II) ions. To address the relationship between physicochemical properties, including solubility in artificial lysosomal fluid, of NiO and time-course changes in the pulmonary response, we conducted an intratracheal instillation study in male Fischer rats using four different well-characterized NiO products, US3352 (NiO A), NovaWireNi01 (NiO B), I small particle (NiO C), and 637130 (NiO D). The NiOs were suspended in purified water and instilled once intratracheally into male F344 rats (12 weeks old) at 0 (vehicle control), 0.67, 2, and 6 mg/kg body weight. The animals were euthanized on days 3, 28, or 91 after instillation, and blood analysis, bronchoalveolar lavage fluid (BALF) testing, and histopathological examination were performed. The most soluble product, NiO B, caused the most severe systemic toxicity, leading to a high mortality rate, but the response was transient and surviving animals recovered. The second-most-soluble material, NiO D, and the third, NiO A, caused evident pulmonary inflammation, and the responses persisted for at least 91 days with collagen proliferation. In contrast, NiO C induced barely detectable inflammation in the BALF examination, and no marked changes were noted on histopathology. These results indicate that the early phase toxic potential of NiO products, but not the persistence of pulmonary inflammation, is associated with their solubility.     

Genetic analysis for sow stayability at different parities in purebred Landrace and Large White pigs

Genetic parameters for sow stayability were estimated from farrowing records of 10,295 Landrace sows and 8192 Large White sows. The record for sow stayability from parity k to parity k + 1 (k = 1, …, 6) was 0 when a sow had a farrowing record at parity k but not at parity k + 1, and 1 when a sow had both records. Heritability was estimated by using single-trait linear and threshold animal models. Genetic correlations among parities were estimated by using two-trait linear–linear and single-trait random regression linear animal models. Genetic correlations with litter traits at birth were estimated by using a two-trait linear–linear animal model. Heritability estimates by linear model analysis were low (0.065–0.119 in Landrace & 0.061–0.157 in Large White); those by threshold model analysis were higher (0.136–0.200 & 0.110–0.283). Genetic correlations among parities differed between breeds and models. Genetic correlation between sow stayability and number born alive was positive in many cases, implying that selection for number born alive does not reduce sow stayability. The results seem to be affected by decisions on culling made by farmers.     

Lactobacillus rhamnosus GG SpaC pilin subunit binds to the carbohydrate moieties of intestinal glycoconjugates

Lactobacillus rhamnosus GG (LGG) is a well‐established probiotic strain. The beneficial properties of this strain are partially dependent on its prolonged residence in the gastrointestinal tract, and are likely influenced by its adhesion to the intestinal mucosa. The pilin SpaC subunit, located within the Spa pili structure, is the most well studied LGG adhesion factor. However, the binding epitopes of SpaC remain largely unknown. The aim of this study was to evaluate the binding properties of SpaC to the carbohydrate moieties of intestinal glycoconjugates using a recombinant SpaC protein. In a competitive enzyme‐linked immunosorbent assay, SpaC binding was markedly reduced by addition of purified mucin and the mucin oligosaccharide fraction. Histochemical staining revealed that the binding of SpaC was drastically reduced by periodic acid treatment. Moreover, in the surface plasmon resonance‐based Biacore assay, SpaC bound strongly to the carbohydrate moieties containing β‐galactoside at the non‐reducing terminus of glycolipids. We here provide the first demonstration that SpaC binds to the oligosaccharide chains of mucins, and that the carbohydrate moieties containing β‐galactoside at the non‐reducing termini of glycoconjugates play a crucial role in this binding. Our results demonstrate the importance of carbohydrates of SpaC for mucus interactions.     

Canine fetal echocardiography: correlations for the analysis of cardiac dimensions

The aim of this study was to develop regression models for correlation of canine fetal heart development with body size to characterize normal development or suggest cardiac anomalies. Twenty clinically healthy pregnant bitches, either brachycephalic and non-brachycephalic, were examined ultrasonographically. Transabdominal fetal echocardiography was conducted every 4 days from the beginning of cardiac chambers differentiation until parturition. Ten cardiac parameters were measured: length, width and diameter of the heart; heart area; left and right ventricular dimensions; left and right atrial dimensions; and aortic and pulmonary artery diameter. Femoral length, biparietal diameter and abdominal cross-sectional area were also recorded. Regression equations were developed for each parameter of fetal body size, and linear and logarithmic models were compared. The model with the highest correlation coefficient was chosen to produce equations to calculate relative dimensions based on the correlations. Only the left-ventricular chamber differed between the two racial groups. Biparietal diameter was the independent parameter that produced the highest correlation coefficient for the most fetal cardiac dimensions, although good correlations were also observed using femoral length and abdominal cross-sectional area. Heart width and heart diameter were used as surrogates of cardiac development, as these measurements showed the best statistical correlation. Quantitative evaluation of fetal cardiac structures can be used to monitor normal and abnormal cardiac development.