Oxidant-induced haemoprotein degradation in rat tissue slices: effect of bromotrichloromethane, antioxidants and chelators

Haemoprotein degradation and lipid peroxidation were evaluated in rat liver, kidney and heart slices incubated for 2 h in the presence and absence of bromotrichloromethane, antioxidants and chelators to obtain information about the relationship between oxidants and damage to haemoproteins. Haemoproteins were modified by bromotrichloromethane, and this modification, measured as loss of ferrohaemoproteins, generally was concurrent with lipid peroxidation measured as thiobarbituric acid-reactive substances. These two processes occurred simultaneously as a function of incubation time and oxidant concentration. Inhibition of the two processes by nordihydroguaiaretic acid, butylated hydroxyanisole and Trolox C, and lack of inhibition by mannitol, catalase and superoxide dismutase also were coincident. However, Methylene blue, EDTA, sodium fluoride, 2,4-dinitrophenol, N-ethylmaleimide and o-phenanthroline affected the two processes differently. The results suggested that haemoproteins may compete with other molecules for oxidant radicals, thus serving as protectors of cells against oxidant radicals. Products of haemoprotein degradation such as protein polymers, free amino acids and bilirubin may be indicators of in vivo oxidative stress.     

Inhibitors of sphingolipid metabolism enzymes

Sphingolipids are a family of lipids that play essential roles both as structural cell membrane components and in cell signalling. The cellular contents of the various sphingolipid species are controlled by enzymes involved in their metabolic pathways. In this context, the discovery of small chemical entities able to modify these enzyme activities in a potent and selective way should offer new pharmacological tools and therapeutic agents.     

Deciphering the Metabolic Changes Associated with Diapause Syndrome and Cold Acclimation in the Two-Spotted Spider Mite Tetranychus urticae

Diapause is a common feature in several arthropod species that are subject to unfavorable growing seasons. The range of environmental cues that trigger the onset and termination of diapause, in addition to associated hormonal, biochemical, and molecular changes, have been studied extensively in recent years; however, such information is only available for a few insect species. Diapause and cold hardening usually occur together in overwintering arthropods, and can be characterized by recording changes to the wealth of molecules present in the tissue, hemolymph, or whole body of organisms. Recent technological advances, such as high throughput screening and quantification of metabolites via chromatographic analyses, are able to identify such molecules. In the present work, we examined the survival ability of diapausing and non-diapausing females of the two-spotted spider mite, Tetranychus urticae, in the presence (0 or 5°C) or absence of cold acclimation. Furthermore, we examined the metabolic fingerprints of these specimens via gas chromatography-mass spectrophotometry (GC-MS). Partial Least Square Discriminant Analysis (PLS-DA) of metabolites revealed that major metabolic variations were related to diapause, indicating in a clear cut-off between diapausing and non-diapausing females, regardless of acclimation state. Signs of metabolic depression were evident in diapausing females, with most amino acids and TCA cycle intermediates being significantly reduced. Out of the 40 accurately quantified metabolites, seven metabolites remained elevated or were accumulated in diapausing mites, i.e. cadaverine, gluconolactone, glucose, inositol, maltose, mannitol and sorbitol. The capacity to accumulate winter polyols during cold-acclimation was restricted to diapausing females. We conclude that the induction of increased cold hardiness in this species is associated with the diapause syndrome, rather than being a direct effect of low temperature. Our results provide novel information about biochemical events related to the cold hardening process in the two-spotted spider mite.     

Sex differences in intraventricular hemorrhage rates among very low birth weight newborns

Background: The influence of male or female sex on newborn outcomes has been recognized for >30 years. Several studies have observed higher mortality and morbidity in males than in females. It is not clear how this sex difference is sustained in postnatal complications such as intraventricular hemorrhage (IVH), especially in very low birth weight (VLBW) newborns.Objective: This study examined possible sex-related differences in IVH rates among VLBW neonates.Methods: In a retrospective observational study conducted in Hospital Privado, Córdoba, Argentina, data from 332 consecutive VLBW newborns in a 12-year period were reviewed. Maternal factors, labor and delivery characteristics, and neonatal parameters, including the results of cranial ultrasound examination to detect IVH, were compared for males and females. Bivariate and multivariate logistic regression analyses were performed.Results: A total of 322 VLBW newborns were included, 168 males and 154 females. Compared with female neonates, male neonates had a higher risk of overall IVH (26.8% vs 9.7%; odds ratio [OR] = 3.4 [95% CI, 1.8–6.4]; P < 0.001) and for grades III or IV on the Papile scale (16.1% vs 1.9%; OR = 9.6 [95% CI, 2.9–32.5]; P < 0.001). In the multivariate logistic regression model, male sex sustained the association with a greater risk of IVH (OR = 6.8 [95% CI, 3.8–12.0]).Conclusions: IVH was significantly associated with male sex in these VLBW newborns. Because other factors affect these differences, further research is required.