Protective effect of CardiPro against doxorubicin-induced cardiotoxicity in mice

The effect of CardiPro, a polyherbal formulation, with an antioxidant property, has been studied on doxorubicin (DXR)-induced cardiotoxicity in mice. CardiPro (150 mg/kg b.w., twice daily was administered orally for 7 weeks along with four equal injections (each containing 4.0 mg/kg b.w., DXR) intraperitoneally, once weekly (cumulative dose 16 mg/kg). After a 3-week post DXR treatment period, cardiotoxicity was assessed by noting mortality, volume of ascites, liver congestion, changes in heart weight, myocardial lipid peroxidation, antioxidant enzymes and histology of heart. DXR-treated animals showed higher mortality (50%) and more ascites. Myocardial SOD and glutathione peroxidase activity were decreased and lipid peroxidation was increased. Histology of heart of DXR-treated animals showed loss of myofibrils and focal cytoplasmic vacuolization. CardiPro significantly protected the mice from DXR-induced cardiotoxic effects as evidenced by lower mortality (25%), less ascites, myocardial lipid peroxidation, normalization of antioxidant enzymes and minimal damage to the heart histologically. Our data confirm the earlier reports that DXR cardiotoxicity is associated with the free radical-induced tissue damage. Administration of CardiPro, with an antioxidant property, protected the DXR-induced cardiotoxicity in mice.     

Osmolyte accumulation in different rape genotypes under sodium chloride salinity

Physiological mechanisms of two rape (Brassica napus L.) genotype adaptation to chlorine salinity were investigated. The plants of two cultivars (Olga and Westar) differing in salt tolerance were grown in the pots filled with Perlite on the Hoagland and Snyder’s medium under controlled conditions. At a stage of 3–4 true leaves, the plants experienced 7-day-long salinity induced by a single addition of NaCl to the nutrient medium in order to attain desired final salt concentration (from 50 to 400 mM). The obtained results showed that a greater salt tolerance of cv. Olga plants (as compared with cv. Westar) could be accounted for by a capability of their root cells to uptake water under high salinity (300–400 mM NaCl), which is evident from a greater content of water in the tissues of cv. Olga. This was ensured by a sharp fall of the osmotic potential of the cellular contents (down to −2.3 MPa) at a low water potential of nutrient solution owing to more active uptake of Na⁺ (57–61 μeq/g fr wt) and K⁺ (210–270 μeq/g fr wt) as well as active accumulation of proline (30–50 μmol/g fr wt). The latter is caused by a reduced activity of proline dehydrogenase and retarded degradation of this osmolyte. It is important that, in contrast to less tolerant genotype, the rape plants of salt-resistant cultivar were able to maintain the K⁺/Na⁺ ratio at a rather high level at salinity of different degree, which made it possible to preserve ionic homeostasis under adverse conditions. Original Russian Text ? A.M. Mokhamed, G.N. Raldugina, V.P. Kholodova, Vl.V. Kuznetsov, 2006, published in Fiziologiya Rastenii, 2006, Vol. 53, No. 5, pp. 732–738.     

Hydrogen sulfide donor sodium hydrosulfide-improved heat tolerance in maize and involvement of proline

Hydrogen sulfide (H₂S) has long been considered as a phytotoxin, but nowadays as a cell signal molecule involved in growth, development, and the acquisition of stress tolerance in higher plants. In the present study, hydrogen sulfide donor, sodium hydrosulfide (NaHS), pretreatment markedly improved germination percentage of seeds and survival percentage of seedlings of maize under heat stress, and alleviated an increase in electrolyte leakage of roots, a decrease in tissue vitality and an accumulation of malondialdehyde (MDA) in coleoptiles of maize seedlings. In addition, pretreatment of NaHS could improve the activity of Δ¹-pyrroline-5-carboxylate synthetase (P5CS) and lower proline dehydrogenase (ProDH) activity, which in turn induced accumulation of endogenous proline in maize seedlings. Also, application of proline could enhance endogenous proline content, followed by mitigated accumulation of MDA and increased survival percentage of maize seedlings under heat stress. These results suggest that sodium hydrosulfide pretreatment could improve heat tolerance of maize and the acquisition of this heat tolerance may be involved in proline.     

Glucocerebrosidase inhibition causes mitochondrial dysfunction and free radical damage

Mutations of the gene for glucocerebrosidase 1 (GBA) cause Gaucher disease (GD), an autosomal recessive lysosomal storage disorder. Individuals with homozygous or heterozygous (carrier) mutations of GBA have a significantly increased risk for the development of Parkinson’s disease (PD), with clinical and pathological features that mirror the sporadic disease. The mechanisms whereby GBA mutations induce dopaminergic cell death and Lewy body formation are unknown. There is evidence of mitochondrial dysfunction and oxidative stress in PD and so we have investigated the impact of glucocerebrosidase (GCase) inhibition on these parameters to determine if there may be a relationship of GBA loss-of-function mutations to the known pathogenetic pathways in PD. We have used exposure to a specific inhibitor (conduritol-β-epoxide, CβE) of GCase activity in a human dopaminergic cell line to identify the biochemical abnormalities that follow GCase inhibition. We show that GCase inhibition leads to decreased ADP phosphorylation, reduced mitochondrial membrane potential and increased free radical formation and damage, together with accumulation of alpha-synuclein. Taken together, inhibition of GCase by CβE induces abnormalities in mitochondrial function and oxidative stress in our cell culture model. We suggest that GBA mutations and reduced GCase activity may increase the risk for PD by inducing these same abnormalities in PD brain.     

Probing antioxidant activity of 2′-hydroxychalcones: Crystal and molecular structures, in vitro antiproliferative studies and in vivo effects on glucose regulation

In order to better understand the antioxidant behavior of a series of polyphenolic 2′-hydroxychalcones, we describe the results of several chemical and biological studies, in vitro and in vivo. Single crystal X-ray methods elucidated their molecular structures and important intermolecular interactions such as H-bonding and molecular stacking in the crystal structures that contribute to our knowledge in explaining antioxidant activity. The results of experiments using the 1,1-diphenyl-2-dipicrylhydrazyl (DPPH) UV–vis spectroscopic method indicate that a hydroxyl group in position 5′ induces the highest antioxidant activity. Consequently, 2,2′,5′-trihydroxychalcone was selected for further study in vitro towards ROS scavenging in L-6 myoblasts and THP-1 human monocytes, where it shows an excellent antioxidant activity in a concentration range lower than that reported by most studies of related molecules. In addition, this chalcone shows a very selective activity: it inhibits the proliferation of leukemic cells, but it does not affect the normal L-6 myoblasts and human fibroblasts. In studying 2,2′,5′-trihydroxychalcone's effect on weight gain and serum glucose and insulin levels in Zucker fatty (fa⁻/fa⁻) rats we found that supplementing the diet with a 10 mg/kg dose of this chalcone (3 times weekly) blunted the increase in glucose that co-occurs with weight gain over the 6-week treatment period. It is concluded that 2,2′,5′-trihydroxychalcone has the potential to serve as a protective agent for some debilitating diseases.     

Regio- and stereoselective oxygenation of proline derivatives by using microbial 2-oxoglutarate-dependent dioxygenases

We evaluated the substrate specificities of four proline cis-selective hydroxylases toward the efficient synthesis of proline derivatives. In an initial evaluation, 15 proline-related compounds were investigated as substrates. In addition to l-proline and l-pipecolinic acid, we found that 3,4-dehydro-l-proline, l-azetidine-2-carboxylic acid, cis-3-hydroxy-l-proline, and l-thioproline were also oxygenated. Subsequently, the product structures were determined, revealing cis-3,4-epoxy-l-proline, cis-3-hydroxy-l-azetidine-2-carboxylic acid, and 2,3-cis-3,4-cis-3,4-dihydroxy-l-proline.     

Melatonin Entrains Free‐running Blind People According to a Physiological Dose‐response Curve

The specific circadian role proposed for endogenous melatonin production was based on a study of sighted people who took low pharmacological doses (500 µg) of this chemical signal for the “biological night”: the magnitude and direction of the induced phase shifts were dependent on what time of day exogenous melatonin was administered and were described by a phase‐response curve that turned out to be the opposite of that for light. We now report that lower (physiological) doses of up to 300 µg can entrain (synchronize) free‐running circadian rhythms of 10 totally blind subjects that would otherwise drift later each day. The resulting log‐linear dose‐response curve in the physiological range adds support for a circadian function of endogenous melatonin in humans. Efficacy of exogenous doses in the physiological range are of clinical significance for totally blind people who will need to take melatonin daily over their entire lifetimes in order to remain entrained to the 24 h day. Left untreated, their free‐running endocrine, metabolic, behavioral, and sleep/wake cycles can be almost as burdensome as not having vision.     

Estimation of Free Energy Systematic Errors in Molecular Simulations of Globular Proteins Surrounded by Finite Water Clusters. One Center Multipole Expansion of Reaction Field Differences

Free energy calculated in simulations on the atomic level (Monte Carlo or Molecular Dynamics) has a systematic error, if the water shell surrounding a globular protein is finite. The error (“cluster error”) is equal to a difference of free energies obtained in simulations with an infinite and finite water shell. In this work a continuum dielectric model was used to estimate the “cluster error”. A multipole expansion of the estimate was performed for a water shell with a spherical outer boundary. The expansion has very simple form. Each term is a product of two functions, one of them depending only on the charge's conformation, and the other one only on dielectric properties of the system. There are two practical uses of the expansion. First, it may be used to estimate the “cluster error” in a simulation already made; second, it may be used to plan a simulation in such a way that the “cluster error” is minimal. Numerical values of the largest terms in the multipole expansion corresponding to a typical system in simulations of globular proteins are given.     

Assessment of macrophage migration inhibitory factor in humans: protocol for accurate and reproducible levels

The analytical validation of a possible biomarker is the first step in the long translational process from basic science to clinical routine. Although the chemokine-like cytokine macrophage migration inhibitory factor (MIF) has been investigated intensively in experimental approaches to various disease conditions, its transition into clinical research is just at the very beginning. Because of its presence in preformed storage pools, MIF is the first cytokine to be released under various stimulation conditions. In the first proof-of-concept studies, MIF levels correlated with the severity and outcome of various disease states. In a recent small study with acute coronary syndrome patients, elevation of MIF was described as a new factor for risk assessment. When these studies are compared, not only MIF levels in diseased patients differ, but also MIF levels in healthy control groups are inconsistent. Blood MIF concentrations in control groups vary between 0.56 and 95.6 ng/ml, corresponding to a 170-fold difference. MIF concentrations in blood were analyzed by ELISA. Other than the influence of this approach due to method-based variations, the impact of preanalytical processing on MIF concentrations is unclear and has not been systematically studied yet. Before large randomized studies are performed to determine the impact of circulating MIF on prognosis and outcome and before MIF is characterized as a diagnostic marker, an accurate protocol for the determination of reproducible MIF levels needs to be validated. In this study, the measurement of MIF in the blood of healthy volunteers was investigated focusing on the potential influence of critical preanalytical factors such as anticoagulants, storage conditions, freeze/thaw stability, hemolysis, and dilution. We show how to avoid pitfalls in the measurement of MIF and that MIF concentrations are highly susceptible to preanalytical factors. MIF serum concentrations are higher than plasma concentrations and show broader ranges. MIF concentrations are higher in samples processed with latency than in those processed directly and strongly correlate with hemoglobin in plasma. Neither storage temperature nor storage length or dilution or repeated freezing and thawing influenced MIF concentrations in plasma. Preanalytical validation of MIF is essential. In summary, we suggest using plasma and not serum samples when determining circulating MIF and avoiding hemolysis by processing samples immediately after blood drawing.