Cardiotoxicity testing using pluripotent stem cell-derived human cardiomyocytes and state-of-the-art bioanalytics: a review

In this article, recent progress in cardiotoxicity testing based on the use of immortalized cell lines or human embryonic stem cell (hESC) derived cardiomyocytes in combination with state-of-the-art bioanalytical methods and sensors is reviewed. The focus is on hESC-derived cells and their refinement into competent testing cells, but the access and utility of other relevant cell types are also discussed. Recent developments in sensor techniques and bioanalytical approaches for measuring critical cardiotoxicity parameters are highlighted, together with aspects of data evaluation and validation. Finally, recommendations for further research are given.     

Maternal sociodemographic characteristics and risk factors of antepartum fetal death

The objectives of this study were to assess the sociodemographic profile and to identify the risk factors of ante-partum fetal death which occurs after the age of viability of fetus. This prospective observational study was conducted in the Obstetrics department of Ad-din Women Medical College Hospital during the period of June, 2009 to July, 2010. A total of 14,015 pregnant patients were admitted in the study place after the age of viability, which was taken as 28 weeks of gestation for our facilities. Eighty-three (0.59%) of them were identified as intrauterine fetal death. Assessment of maternal sociodemographic characteristics and maternal-fetal risk factors were evaluated with a semi structured questionnaire pretested. Majority (81.92%, n=68) of the patients were below 30 years of age, 78.31% belonged to middle socioeconomic group. Almost 58% women had education below SSC level and 28.91% took regular antenatal checkup. About 61.45% patients were multigravida. Most (59.04%) ante-partum deaths were identified below 32 weeks of pregnancy. Out of 83 patients, maternal risk factors were identified in 41(49.59%) cases where fetal risk factors were found in 16(19.27%) cases; no risk factors could be determined in rests. Hypertension (48.78%), diabetes (21.95%), hyperpyrexia (17.3%), abruptio placentae (4.88%) and UTI (7.36%) were identified as maternal factors; and congenital anomaly (37.5%), Rh incompatibility (37.5%), multiple pregnancy (12.5%) and post-maturity (12.5%) were the fetal risk factors. Here, proximal biological risk factors are most important in ante-partum fetal deaths. More investigations and facilities are needed to explain the causes of antepartum deaths.     

Oxidative stress and toxicity induced by the nucleoside reverse transcriptase inhibitor (NRTI)--2',3'-dideoxycytidine (ddC): relevance to HIV-dementia

Human immunodeficiency virus dementia (HIVD) is the most common form of dementia occurring among young adults. In HIVD, neuronal cell loss occurs in the absence of neuronal infection. With the advent of highly active anti-retroviral therapy (HAART), the incidence of HIVD has drastically reduced, though prevalence of milder forms of HIVD continues to rise. Though these agents have been used successfully in suppressing viral production, they have also been associated with a number of side effects. Here we examine the possible role of NRTIs, in particular 2',3'-dideoxycytidine (ddC), in the neuropathology of HIVD. Synaptosomes and isolated mitochondria treated and incubated for 6 h with CSF-achievable concentrations of ddC, i.e., 6-11 ng/ml, were found to show a significant increase in oxidative stress with 40 nM ddC as measured by protein carbonyls and 3-nitrotyrosine (3NT), effects that were not observed in the more tolerable NRTI, 3TC. Protection against protein oxidation induced by ddC was observed when brain mitochondria were isolated from gerbils 1 h after injection i.p. with the brain accessible antioxidant and glutathione mimetic, tricyclodecan-9-yl-xanthogenate (D609). In addition, there is a significant reduction in the levels of anti-apoptotic protein Bcl-2 and a significant increase in cytochrome c release and also a significant increase in the expression of pro-apoptotic protein caspase-3 after mitochondria were treated with 40 nM ddC. The results reported here show that ddC at 40 nM can induce oxidative stress, cause the release of cytochrome c, and in addition, reduce the levels of anti-apoptotic proteins, increase the levels of pro-apoptotic proteins, thereby increasing the possibility for induction of apoptosis. These findings are consistent with the notion of a possible role of the NRTIs, and in particular, ddC, in the mechanisms involved in HIVD.     

An increase in S-glutathionylated proteins in the Alzheimer's disease inferior parietal lobule, a proteomics approach

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by neurofibrillary tangles, senile plaques, and loss of synapses. Many studies support the notion that oxidative stress plays an important role in AD pathogenesis. Previous studies from our laboratory employed redox proteomics to identify oxidatively modified proteins in the AD inferior parietal lobule (IPL) and hippocampus. The proteins were consistent with biochemical or pathological alterations in AD and have been central to further investigations of the disease. The present study focused on the identification of specific targets of protein S-glutathionylation in AD and control IPL by using a redox proteomics approach. For AD IPL, we identified deoxyhemoglobin, alpha-crystallin B, glyceraldehyde phosphate dehydrogenase (GAPDH), and alpha-enolase as significantly S-glutathionylated relative to these brain proteins in control IPL. GAPDH and alpha-enolase were also shown to have reduced activity in the AD IPL. This study demonstrates that specific proteins are sensitive to S-glutathionylation, which most likely is due to their sensitivity to cysteine oxidation initiated by the increase in oxidative stress in the AD brain.     

Redox proteomics identification of oxidatively modified brain proteins in Alzheimer's disease and mild cognitive impairment: insights into the progression of this dementing disorder

Alzheimer disease is a common age-related neurodegenerative disease characterized pathologically by senile plaques, neurofibrillary tangles, synaptic disruption, and progressive neuronal deficits. The senile plaques contain amyloid-beta (1-42) and amyloid-beta (1-40), that has been shown by a number of laboratories to induce oxidative stress and as well as neurodegeneration, although the exact mechanisms remained to be defined. Our laboratory showed an increased oxidative stress in AD and MCI brain as indexed by protein oxidation and lipid peroxidation. In the present review, we summarize our finding of oxidatively modified proteins using a redox proteomics approach in AD and MCI brain to investigate the mechanism that may be involved in MCI and AD pathogenesis and discuss our findings in terms of AD progression and pathogenesis.     

A new depsidone and antibacterial activities of compounds from Usnea undulata Stirton

Usnea undulata Stirton (Usneaaceae) is a fruticose lichen used locally in ethnoveterinary medicine to treat mammary infections in cattle while human beings use it for the treatment of wounds in Eastern Cape, South Africa. Bioactivity-guided fractionation of its extracts led to the isolation and characterization of a new depsidone, 2'-O-methylhypostictic acid (8), together with seven known compounds, i.e. methyl β-orsellinate, norstictic acid, menegazziaic acid, (+) usnic acid, hypoconstictic acid, salazinic acid, and galbinic acid. The structures of the compounds were elucidated on the basis of their spectral analysis including homo- and hetero-nuclear correlation NMR experiments (COSY, NOESY, HMQC, and HMBC) and mass spectra as well as by comparison with available data in the literature. The minimum inhibitory concentrations (MICs) values of the compounds against six bacteria were determined. Compound 8 showed inhibitory activity against Bacillus cereus, Bacillus subtilis, and Staphylococcus epidermidis with MICs of 31, 62.5, 62.5 μg/ml, respectively. (+) Usnic acid was most active against B. subtilis, B. cereus, Staphylococcus aureus, and Escherichia coli with MICs of 8, 8, 31, and 31 μg/ml, respectively, while other compounds exhibited moderate activity.     

Liquid chromatographic analysis of halofantrine from dosage form and its metal interaction studies

The reversed-phase high-performance liquid chromatographic method has been developed for the determination of halofantrine from dosage form in presence of losartan potassium as an internal standard. Separation was performed on a Chrompack hypersil C₁₈ (150 × 4.6 mm) analytical reversed-phase column. Mobile phase consisted of methanol–water (70:30, v/v) pH was adjusted to 3.2 with 85% orthophosphoric acid. Mobile phase was pumped at a flow rate of 0.5 mL min⁻¹ and UV detection was performed at 248 nm. The method was validated for linearity, precision, accuracy and specificity. The linearity was observed in the concentration range 1.0–50 μg mL⁻¹ with correlation coefficient (r ²) of 0.9998. Accuracy was ranged 98–100% with precision less than 1%. The limits of detection (LOD) and (LOQ) were 0.01 and 0.03 μg mL⁻¹, respectively. This method was applied to study the drug–metal (calcium, magnesium, manganese, cobalt, ferrous, ferric chromium, zinc, nickel, cadmium, iron and copper) interaction studies which were carried out at 37 °C. These studies were beneficial to determine the drug in therapeutic concentrations inside human body as well as its complexation with metal ions. The proposed method is rapid, accurate, economical and selective because of its sensitivity and reproducibility.     

Effects of in utero arsenic exposure on child immunity and morbidity in rural Bangladesh

Chronic exposure to arsenic, a potent carcinogen and toxicant, via drinking water is a worldwide public health problem. Because little is known about early-life effects of arsenic on immunity, we evaluated the impact of in utero exposure on infant immune parameters and morbidity in a pilot study. Pregnant women were enrolled at 6–10 weeks of gestation in Matlab, a rural area of Bangladesh, extensively affected by arsenic contamination of tubewell water. Women (n = 140) delivering at local clinics were included in the study. Anthropometry and morbidity data of the pregnant women and their children, as well as infant thymic size by sonography were collected. Maternal urine and breast milk were collected for immune marker and arsenic assessment. Maternal urinary arsenic during pregnancy showed significant negative correlation with interleukin-7 (IL-7) and lactoferrin (Ltf) in breast milk and child thymic index (TI). Urinary arsenic was also positively associated with fever and diarrhea during pregnancy and acute respiratory infections (ARI) in the infants. The effect of arsenic exposure on ARI was only evident in male children. The findings suggest that in utero arsenic exposure impaired child thymic development and enhanced morbidity, probably via immunosuppression. The effect seemed to be partially gender dependent. Arsenic exposure also affected breast milk content of trophic factors and maternal morbidity.     

Liposomal drug delivery systems: an update review

The discovery of liposome or lipid vesicle emerged from self forming enclosed lipid bi-layer upon hydration; liposome drug delivery systems have played a significant role in formulation of potent drug to improve therapeutics. Recently the liposome formulations are targeted to reduce toxicity and increase accumulation at the target site. There are several new methods of liposome preparation based on lipid drug interaction and liposome disposition mechanism including the inhibition of rapid clearance of liposome by controlling particle size, charge and surface hydration. Most clinical applications of liposomal drug delivery are targeting to tissue with or without expression of target recognition molecules on lipid membrane. The liposomes are characterized with respect to physical, chemical and biological parameters. The sizing of liposome is also critical parameter which helps characterize the liposome which is usually performed by sequential extrusion at relatively low pressure through polycarbonate membrane (PCM). This mode of drug delivery lends more safety and efficacy to administration of several classes of drugs like antiviral, antifungal, antimicrobial, vaccines, anti-tubercular drugs and gene therapeutics. Present applications of the liposomes are in the immunology, dermatology, vaccine adjuvant, eye disorders, brain targeting, infective disease and in tumour therapy. The new developments in this field are the specific binding properties of a drug-carrying liposome to a target cell such as a tumor cell and specific molecules in the body (antibodies, proteins, peptides etc.); stealth liposomes which are especially being used as carriers for hydrophilic (water soluble) anticancer drugs like doxorubicin, mitoxantrone; and bisphosphonate-liposome mediated depletion of macrophages. This review would be a help to the researchers working in the area of liposomal drug delivery.