Blood lipid profile and myocardial superoxide dismutase in swim-trained young and middle-aged rats: comparison between left and right ventricular adaptations to oxidative stress

Region-wise interactive effects of age, swim intensity, and duration on exercise performance in the myocardium and serum lipid profile in young (4 months) and middle-aged (12 months) rats were examined. Animals were allocated to the sedentary control (SE-C) or one of the nine trainee groups. Swim training was for 6 days/week and for 4 weeks at 3 durations (20, 40, and 60 min/day) and intensities (2%, low; 3%, medium; 5%, high). Swim velocity and external work showed an age-related decline with low-intensity of 20 min/day in the middle aged. Reduction in serum cholesterol, low-density lipoproteins (LDLs), and triglycerides were accompanied by elevated levels in high-density lipoprotein in the low-to-moderately trained ones for 20 and 40 min/day. Training at 2%, intensity for 20 min/day was sufficient to alter the blood lipid profile and improve swim performance, and endurance in terms of blood lactate. A concomitant increase in Mn-superoxide dismutase (Mn-SOD) activity and reduced malondialdehyde in the left ventricle (LV) and right ventricle (RV) were evident. Lipofuscin was higher in the LV compared to RV. Our results reflect the minimization of free radical generation through appropriate exercise protocols. Our findings on improved blood lipid profile could be related to lower free radicals, which would otherwise oxidize LDLs. Further, swim training when initiated in the young and middle age for as low as 20 min/day at 2% intensity improves the Mn-SOD in the LV and RV. However, the adaptive response of the LV was weaker when compared to the RV, more so in the middle aged.     

Phylogeographic analysis elucidates the influence of the ice ages on the disjunct distribution of relict dragonflies in Asia

Unusual biogeographic patterns of closely related groups reflect events in the past, and molecular analyses can help to elucidate these events. While ample research on the origin of disjunct distributions of different organism groups in the Western Paleartic has been conducted, such studies are rare for Eastern Palearctic organisms. In this paper we present a phylogeographic analysis of the disjunct distribution pattern of the extant species of the strongly cool-adapted Epiophlebia dragonflies from Asia. We investigated sequences of the usually more conserved 18 S rDNA and 28 S rDNA genes and the more variable sequences of ITS1, ITS2 and CO2 of all three currently recognised Epiophlebia species and of a sample of other odonatan species. In all genes investigated the degrees of similarity between species of Epiophlebia are very high and resemble those otherwise found between different populations of the same species in Odonata. This indicates that substantial gene transfer between these populations occurred in the comparatively recent past. Our analyses imply a wide distribution of the ancestor of extant Epiophlebia in Southeast Asia during the last ice age, when suitable habitats were more common. During the following warming phase, its range contracted, resulting in the current disjunct distribution. Given the strong sensitivity of these species to climatic parameters, the current trend to increasing global temperatures will further reduce acceptable habitats and seriously threaten the existences of these last representatives of an ancient group of Odonata.     

Urinary metabolomic phenotyping of nickel induced acute toxicity in rat: an NMR spectroscopy approach

The metabolomic approach has been widely used in toxicology to investigate mechanisms of toxicity. To understand the mammalian system??s response to nickel exposure, we analysed the NiCl₂ induced metabolomic changes in urine of rats using ¹H nuclear magnetic resonance (¹H NMR) spectroscopy together with clinically relevant biochemical parameters. Male Sprague?CDawley rats were administered intraperitoneally with NiCl₂ at doses of 4, 10 and 20?mg/kg body weight. Urine samples were collected at 8, 16, 24, 72, 96 and 120?h post treatment. The metabolomic profile of rat urine showed prominent changes in citrate, dimethylamine, creatinine, choline, trimethylamine oxide (TMAO), phenyl alanine and hippurate at all doses. Principal component analysis of urine ¹H NMR spectra demonstrated the dose and time dependent development of toxicity. The metabolomic time trajectory, based on pattern recognition analysis of ¹H NMR spectra of urine, illustrated clear separation of pre and post treatments (temporal). Only animals treated with a low dose of NiCl₂ returned to normal physiology. The ¹H NMR spectral data correlated well with the clinically relevant nephrotoxic biomarkers. The urinary metabolomic phenotyping for NiCl₂ induced nephrotoxicity was defined according to the predictive ability of the known metabolite biomarkers, creatinine, citrate and TMAO. The current approach demonstrates that metabolomics, one of the most important platform in system biology, may be a promising tool for identifying and characterizing biochemical responses to toxicity.     

A novel mathematical model of bone remodelling cycles for trabecular bone at the cellular level

After an initial phase of growth and development, bone undergoes a continuous cycle of repair, renewal and optimisation by a process called remodelling. This paper describes a novel mathematical model of the trabecular bone remodelling cycle. It is essentially formulated to simulate a remodelling event at a fixed position in the bone, integrating bone removal by osteoclasts and formation by osteoblasts. The model is developed to construct the variation in bone thickness at a particular point during the remodelling event, derived from standard bone histomorphometric analyses. The novelties of the approach are the adoption of a predator-prey model to describe the dynamic interaction between osteoclasts and osteoblasts, using a genetic algorithm-based solution; quantitative reconstruction of the bone remodelling cycle; and the introduction of a feedback mechanism in the bone formation activity to co-regulate bone thickness. The application of the model is first demonstrated by using experimental data recorded for normal (healthy) bone remodelling to predict the temporal variation in the number of osteoblasts and osteoclasts. The simulated histomorphometric data and remodelling cycle characteristics compare well with the specified input data. Sensitivity studies then reveal how variations in the model's parameters affect its output; it is hoped that these parameters can be linked to specific biochemical factors in the future. Two sample pathological conditions, hypothyroidism and primary hyperparathyroidism, are examined to demonstrate how the model could be applied more broadly, and, for the first time, the osteoblast and osteoclast populations are predicted for these conditions. Further data are required to fully validate the model's predictive capacity, but this work shows it has potential, especially in the modelling of pathological conditions and the optimisation of the treatment of those conditions.     

Synthesis and antihyperglycemic activity of novel N-acyl-2-arylethylamines and N-acyl-3-coumarylamines

A series of novel N-acyl-2-arylethylamines and N-acyl-3-coumarylamines were synthesized and evaluated for their antihyperglycemic activity. Compounds 3g and 6d exhibited lowering of postprandial plasma glucose by 30.7%, 23.3% in SLM and 25.6%, 25.4% in STZ models respectively which is significant compared to metformin and glybenclamide. Other compounds exhibited moderate to good activity ranging from 19.5% to 32.8% in SLM and 3.26% to 25.4% in STZ models.     

Effect of aspirin on serum lipoprotein profile in rats subjected to myocardial stress by isoproterenol.

The effect of isoproterenol on the levels of serum lipoprotein profile were studied in rats. Rats were treated with isoproterenol (200 mg/100 g body weight, sc twice at an interval of 24 hr) for 2 days. Aspirin was administered orally 1.2 mg/100 g body weight, daily for 60 days. Isoproterenol treated rats showed decrease in the activities of hepatic and extrahepatic lipoprotein lipase. HDL cholesterol level was found to be decreased, significantly with increase in LDL cholesterol in isoproterenol treated rats. Aspirin treated rats showed marked reversal of these metabolic changes. The lipoprotein changes were minimum in rats treated with both aspirin and isoproterenol.