Oxygen derived free radicals in clinical context

Oxygen derived free radicals have been implicated in a number of clinical disorders including atherosclerosis (1), ischemic heart disease (IHD) (2), post ischemic reperfusion injury (3) and respiratory distress syndrome (4). These radical are generated by sequential reduction of molecular oxygen; the primary product being superoxide anion (O₂ ^.−) which is subsequently reduced to hydrogen peroxide (H₂O₂), hydroxy1 radical (OH^.) and singlet oxygen (¹O₂). However the evidence for ODFR induced cell damage in various clinical disorders is still debated and rests largely on free radical scavenging studies, through electron paramagnetic resonance spectroscopic (EPRS) studies have provided direct evidence for ODFR generation following coronary artery ligation (5). By definition, a free radical is an atom, ion or molecule with one or more unpaired electrons (the presence of unpaired electron in a free radical being represented by a superscribed bold dot-R^.) and may be formed as a result of homolytic fission of a covalent bond or by electron transfer reactions, and may have cationic (NH₃ ⁺), anionic (O₂ ^.−) or neutral (NO) characteristics. The most important in vivo source for these radical species have been found to be univalent biochemical redox reactions involving oxygen. (a) A:B→A^.+B^. (b) A:+B→A^.+B^.     

Discrimination‐Related Stress Effects on the Development of Internalizing Symptoms Among Latino Adolescents

This three‐wave longitudinal study of 173 Latino adolescents (M = 16.16 years, SD = 0.65) is designed to understand the role of discrimination‐related stress in mental health trajectories during middle to late adolescence with attention to differences due to immigration status. The results of the growth curve analysis showed that anxious‐depressed, withdrawn‐depressed, and somatic complaints significantly decreased over time. Furthermore, although discrimination‐related stress was found to be significantly related to the trajectories of three types of mental health symptoms, the results revealed that immigration status moderated these relations such that discrimination‐related stress was significantly related to these outcomes for Latino youth whose parents were born in the United States, while this relation was not significant for Latino children of immigrants.     

Kinetic analysis of LDL oxidation in IHD and IHD risk subjects in Indian population

High plasma concentration of low-density lipoprotein (LDL) is associated with increased risk of atherosclerosis. Modified forms of LDL, especially oxidized LDL play a major role in its pathogenesis. This article gives detailed insight into the kinetics ofin vitro LDL oxidation by copper at different concentrations in normal and high-risk group subjects. Basal level of oxidatively modified LDL was significantly higher in ischaemic heart disease (IHD) and IHD hyperlipidemic subjects compared to normolipidemic and, hyperlipidemic control subjects, respectively. Derivatization of amino groups of apo-lipoprotein as monitored by estimating free amino groups concentration, was significantly higher in high-risk group and established IHD cases. Kinetics of oxidation was studied with two different concentrations of CuSO₄ (2.5 mM and 7.5 mM). thiobarbituric acid reactive substances (TBARS) level increases with time, and up to 95% oxidation was observed in 8 hr. About 60–65% less free amino groups were observed in native-LDL isolated from IHD patients compared to normal subjects. Study also showed an increase in two oxidative products studied, 20α-OH-cholesterol and 4-cholesten-3-one with oxidation time accompanied by corresponding decrease in LDL cholesterol. Increase in oxidative species was more evident in high-risk group and IHD patient. Basal level of oxidatively modified LDL measured in terms of TBARS was significantly higher in present study, strongly support that the extent of LDL oxidation monitored as TBARS and FAG level in circulating-LDL could be used as risk marker for high risk group.     

Pro-oxidant and anti-oxidant status in patients of sickle cell anaemia

The role of oxidant damage to red cells in sickle cell anaemia has been of interest in recent years. Although, available reports suggest that sickle cell erythrocytes are susceptible to endogenous free radical mediated oxidant damage there remains discrepancy in the status of antioxidant enzymes and antioxidant vitamins in these patients. In view of this, 107 cases of sickle cell anaemia (36 ‘SS’ and 71 ‘AS’ pattern—as confirmed by haemoglobin electrophoresis) were subjected to analysis of malondialdehyde, ascorbic acid, superoxide dismutase and albumin. The results were compared with 54 age and sex matched healthy controls. The results indicate a marked increase in lipid peroxidation and superoxide dismutase levels in both ‘SS’ and ‘AS’ types of sickle cell anaemia as compared to controls. Although no difference was observed in the levels of albumin in these groups the levels of ascorbic acid were significantly depleted in sickle cell anaemia patients. The results are indicative of enhanced lipid peroxidation along with imbalance in the pro-oxidant and antioxidant status in patients of sickle cell anaemia.     

Hypoxia-Induced Inflammatory Chemokines in Subjects with a History of High-Altitude Pulmonary Edema

High altitude hypoxia is known to induce an inflammatory response in immune cells. Hypoxia induced inflammatory chemokines may contribute to the development of high altitude pulmonary edema (HAPE) by causing damage to the lung endothelial cells and thereby capillary leakage. In the present study, we were interested to know whether chronic inflammation may contribute to HAPE susceptibility. We examined the serum levels of macrophage inflammatory protein-1α (MIP-1α), monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 in group (1) HAPE Susceptible subjects (n = 20) who had past history of HAPE and group (2) Control (n = 18) consist of subjects who had stayed at high altitude for 2 years without any history of HAPE. The data obtained confirmed that circulating MCP-1, MIP-1α were significantly upregulated in HAPE-S individuals as compared to the controls suggestive of chronic inflammation. However, it is not certain whether chronic inflammation is cause or consequence of previous episode of HAPE. The moderate systemic increase of these inflammatory markers may reflect considerable local inflammation. The existence of enhanced level of inflammatory chemokines found in this study support the hypothesis that subjects with past history of HAPE have higher baseline chronic inflammation which may contribute to HAPE susceptibility.     

Chemical composition of biliary calculi from Kanpur region

Gallstones from 24 female patients were subjected to quantitative chemical analysis. Two main categories of stones were identified: (1) Ten cholesterol stones with 93.38% cholesterol and only 0.17% bilirubin. (2) Mixed stones with cholesterol below 65%. They were sub-divided in two groups: (a) Six stones having 0.5% bilirubin and (b) Eight stones having 0.5% bilirubin. The calcium of cholesterol and mixed stones was comparable while phosphorus contents in cholesterol stones were low by over 30% in mixed stones.     

Glycosylated haemoglobin-a diagnostic tool in pregnant diabetics

Blood samples of 40 pregnant women were analysed for glycosylated haemoglobin (HbA1c) and blood sugar. The patients were followed up till delivery and their obstetric outcome was analysed in conjunction with the glycaemic profile and the level of glycosylated haemoglobin. Group I comprising the normal pregnant women showed a mean HbA1c of 6.23% at 20–40 weeks of gestation. In contrast the diabetic pregnant women (group II) at the same gestation demonstrated an HbA1c of 9.4%. Further group IIA of gestational diabetic women showed an HbA1c of 8.97% and group IIB comprising the overt diabetics had HbA1c of 9.86%. The mother who delivered a congenitally malformed child had an elevated HbA1c of 10.4% during pregnancy. Seven cases of macrosomia were reported and the mean HbA1c of their mothers at 20–40 weeks of gestation was found to be 9.91%. Six mothers delivered infants who developed respiratory distress syndrome (RDS) soon after birth and all these six had elevated HbA1c with a mean of 8.9%. Abortions were also associated with elevated HbA1c of 10.3% antenatally. One case of still birth was reported and the mother demonstrated an elevated glycosylated haemoglobin during pregnancy. An HbA1c of 10% or more was associated with abortion, still-birth, or congenitally malformed babies.