Lead: Tiny but Mighty Poison

The documentation of lead toxicity (plumbism) dates back to the times when man learnt its various applications. This versatile heavy metal is non-degradable and its ability to get accumulated in the body that goes undiagnosed, makes it a serious environmental health hazard. Lead is now known to affect almost every organ/tissue of the human body. With irreversible effects on neurobiological development of young children and foetus, its toxicity has lasting implications on the human life. Outlining the symptoms, diagnosis and treatment therapy for lead poisoning, the present review elaborates the pathophysiological effects of lead on various organs. This will be of immense help to the health professionals so as to inculcate a better understanding of the lead poisoning which otherwise is asymptomatic. With chelation therapy being the classic path of treatment, new strategies are being explored as additive/adjunct therapy. It is now understood that lead toxicity is completely preventable. In this regard significant efforts are in place in the developed countries whereas much needs to be done in the developing countries. Spreading the awareness amongst the masses by educating them and reducing the usage of lead following stricter industry norms appears to be the only roadmap to prevent lead poisoning. Efforts being undertaken by the Government of India and other organisations are also mentioned.     

Perfectionism and training distress in junior athletes: The mediating role of coping tendencies

Training distress occurs when athletes fail to cope with physiological and psychological stress and can be an early sign of overtraining syndrome. Recent research has found that perfectionism predicts increases in training distress in junior athletes over time. The current study provides the first empirical test of the possibility that coping tendencies mediate the perfectionism-training distress relationship. Adopting a cross-sectional design, 171 junior athletes (mean age?=?18.1 years) completed self-report measures of perfectionistic strivings, perfectionistic concerns, problem-focused coping, avoidant coping, and training distress. Structural equation modelling revealed that avoidant coping mediated the positive relationship between perfectionistic concerns and training distress, and mediated the negative relationship between perfectionistic strivings and training distress. Problem-focused coping did not mediate any relationships between dimensions of perfectionism and training distress. The findings suggest that the tendency to use coping strategies aimed at avoiding stress may partly explain the relationship between perfectionism and training distress but the tendency to use, or not use, problem-focussed coping does not.     

Lysyl Oxidase: Its Diversity in Health and Diseases

The mechanical properties of extracellular matrix (ECM) and connective tissues is largely dependent on the collagen and elastin structure. Lysyl oxidase (LOX) plays a critical role in the formation and repair of the ECM by oxidizing lysine residues in elastin and collagen, thereby initiating the formation of covalent cross linkages which stabilize these fibrous proteins. Due to its multiple functions both extracellularly and intracellularly, lysyl oxidase is involved in several processes in the tumorigenic pathway, in many different cancer types and stages. Alteration in LOX activity is implicated in many diseases and disorders including inflammation and inflammatory diseases, fibrosis of distinct organs and fibrotic disorders, cancer promotion and progression. There are only sparse reports of mutations or epigenetic alterations in the LOX gene. This review provides the recent clinical developments in the molecular mechanisms and pathologic process, pointing out LOX as a potential therapeutic target in translational medicine.     

Circadian Periodicity of Circulating Plasma Lipid Peroxides,Uric Acid and Ascorbic Acid in Renal Stone Formers

Circadian periodicity of plasma lipid peroxides and serum ascorbic acid and uric acid levels were studied in one hundred renal stone formers (55 women and 45 men; age 20–60 years) and 50 clinically healthy volunteers (21 women and 29 men; age 21–45 years) with diurnal activity from 06:00 to 22:00 and nocturnal rest. A marked circadian variation was demonstrated by population-mean-cosinor for all studied variables in stone formers and healthy subjects. By comparison to the healthy controls, parameter tests indicate that the stone formers had a higher MESOR (±SE) of MDA (2.90 ± 0.03 vs. 2.28 ± 0.06; F = 94.929, p < 0.001), a lower MESOR of serum ascorbic acid (0.722 ± 0.010 vs. 0.839 ± 0.10; F = 32.083, p < 0.001), and a similar MESOR of serum uric acid. Furthermore, the patients also differed from the healthy subjects in terms of their circadian amplitude and acrophase (tested jointly) of all three variables (p < 0.001). The demonstration herein of a circadian rhythm in MDA, serum ascorbic and uric acid suggests that these variables could also serve as markers to optimize the timing of treatment and to assess the patient’s response to treatment for further management.     

PAI-1 Study in Thalassemia Major Patients Receiving Multiple Blood Transfusion

Thalassemia is a congenital hemolytic disease which is treated by repeated blood transfusion. Chronic iron overload is currently considered to be the primary cause of mortality in β-thalassemia, mainly due to the induction of left-sided cardiac failure. Iron overload results from a number of mechanisms associated with the disease itself. In addition to chronic iron overload thalassemic patients are more prone for procoagulant status which in turn lead to clinical thrombotic events. The hypercoagulable state in thalassemia is due to multiple elements, a combination of which is often the drive behind a clinical thromboembolic events. PAI-1 study was done in thalassemia major patients receiving multiple blood transfusion as a marker for procoagulant status. Total of 30 thalassemic patients on repeated blood transfusion was included in the study and total of 30 healthy age and sex matched controls were included in the study. It was also found that there was significant differences between cases and controls. The mean level of PAI 1 in controls was 3047 ± 414 pg/ml, the value in cases was 3683 ± 358 pg/ml. The level was significantly increased (p < 0.05) in the cases compared to controls. PAI-1 levels were also compared with the total number of blood transfusion which correlates well.     

A metric measure for direct comparison of competing models in covariance structure analysis

Comparing the fit of alternative models has become a standard procedure for analyzing covariance structure analysis. Comparison of alternative models is typically accomplished by examining the fit of each model to sample data. It is argued that rather than using this indirect approach, one should do direct comparisons of the similarities and differences among competing models. It is shown that among the existing good‐ness‐of‐fit indexes, the root mean square residual (RMSR) is the only one that can be used for this purpose. However, the RMSR fails to satisfy some important statistical desiderata. Rao's Distance (RD), an alternate measure, is shown to overcome this limitation of RMSR. The preference for RD over RMSR for model comparisons is illustrated through a detailed analysis of a particular sample of multitrait‐multimethod data. A simulation study conducted to empirically investigate the sampling behavior of RD reveals that the true orderings of intermodel proximities are recovered (on average) with a fair degree of accuracy.     

An Examination of Factors Influencing Students Selection of Business Majors Using TRA Framework

Making decisions regarding the selection of a business major is both very important and challenging for students. An understanding of this decision‐making process can be valuable for students, parents, and university programs. The current study applies the Theory of Reasoned Action (TRA) consumer decision‐making model to examine factors that influence college students’ intentions to choose a business major. A total of 670 undergraduate students enrolled at a large midwestern university participated in the study. Social image, job availability, and aptitude were found to be significant factors that impact students’ decisions to select a business major. The results also reveal that family, high‐school counselors, and professors have a major influence on students’ decisions. Furthermore, some unique differences were found related to gender and decided/undecided status of students. The implications of these results for promoting different majors and future research are discussed.     

Purification and characterization of chymotrypsin-like enzyme from rat plasma

A chymotrypsin-like enzyme was purified from rat plasma, involving ammonium sulfate fractionation and chromatographgy on CM-sephadex and red sepharose. The purified enzyme effectively hydrolysed the ester substrates for chymotrypsin (N-acetyl L-tyrosine ethyl ester and N-acetyl L-tryptophan ethyl ester). The Km values for the two substrates were 2.2×10^?3M and 9.0×10^?3M respectively. The hydrolytic activity of the enzyme was inhibited by phenylmethyl sulfonyl fluoride and tosylphenylalanine chloromethylketone, suggesting the presence of serine and histidine at the active centre. The enzyme exhibited anionic nature and possessed a high molecular weight (MW 71,000) as observed by gel exclusion chromatography on Sephadex G-200. The enzyme was stable upon exposure to pH 7.0–9.0, but was inactivated upon heat treatment at 60°C for 5 min.     

Sialic acid in cardiovascular diseases

Sialic acid, the acylated derivatives of 9-carbon sugar neuraminic acid, present as terminal component of oligosaccharide chains of many glycoproteins and glycolipids, has been recognized to be involved in the regulation of a great variety of biological phenomena. Studies have shown that serum sialic acid predicts both coronary heart disease and stroke mortality and reflects the existence or activity of an atherosclerotic process. Most of the studies have shown an elevation in serum sialic acid concentration in coronary heart disease and a positive correlation between the raised serum sialic acid and the severity of the coronary lesions is observed. However, a few contradictory reports are also available. Racial differences in serum sialic acid have also been reported and correlated with international differences in the prevalence of atherosclerosis. Reduced sialic acid content of platelets, erythrocytes and lipoproteins may play important role in the pathogenesis of atherosclerosis. Elucidation of the mechanism of alternation in sialic acid concentration may throw more light on its potential clinical utility. Hence more studies are needed to designates sialic acid as a cardiovascular risk factor/marker.