The multiple drug resistance gene,MDR1: Expression at the protein and RNA levels

A comparison of three different approaches to detect MDR₁ expression in myeloid leukemia cells was undertaken. With respect to the 4 different antibodies studied, a high proportion of false positive reactions were detected. Substantial discordance between MDR₁ expression as indicated by Northern blot analysis, PCR, and immunohistochemistry was found. These findings complicate the clinical interpretation of data derived from these methods.     

Intrauterine cerebral infarcts and bilateral frontal cortical leukomalacia following chronic maternal inhalation of carburetor cleaning fluid during pregnancy.

Little is known about the effect of inhalation of methanol and other solvents on the pregnancy and the growth of the fetus. We report a preterm male infant who developed cerebral infarcts in utero, leading to large areas of bilateral frontal cortical leukomalacia following chronic maternal inhalation of carburetor-cleaning fluid during pregnancy. The infant presented with acute fetal distress with significant metabolic acidosis at birth. Initial hypotonia was followed by generalized hypertonicity. This infant did not exhibit typical facial features of fetal alcohol syndrome.     

Selective sensitivity of synaptosomal membrane function to cerebral cortical hypoxia in newborn piglets

The effect of hypoxia on the structure and function of the synaptosomal membranes and myelin fraction (glial cells, neuronal cell bodies and axonal membranes) was investigated by measuring Na⁺,K⁺-ATPase activity and levels of lipid peroxidation products in cerebral cortical synaptosomal membranes and myelin fractions obtained from newborn piglets. Hypoxic hypoxia was induced and cerebral hypoxia was documented as a decrease in the ratio of phosphocreatine to inorganic phosphate (PCr/Oi) using³¹P-NMR spectroscopy. PCr/Pi decreased from baseline of2.93 ± 0.76to0.61 ± 0.36 during hypoxia. The synaptosomal membrane Na⁺,K⁺-ATPase activity decreased from a control value of56.6 ± 3.7to40.4 ± 6.0 μgmol Pi/mg protein/h during hypoxia. The level of conjugated dienes increased from zero (reference value) to4.5 ± 2.7 nmol/mg lipid and the level of fluorescent compounds increased from23.5 ± 2.2to92.6 ± 46.4 ng quinine sulfate/mg lipid in the synaptosomal membranes during hypoxia. No change in myelin fraction Na⁺,K⁺-ATPase activity or levels of lipid peroxidation products were noted. These data indicate that sunaptosomal membranes, rich in polyunsaturated fatty acids, are more susceptible to oxygen free radical mediated lipid peroxidative damage during hypoxia.     

No evidence for humoral autoimmunity against cardiomyocytes,adrenergic or muscarinic receptors in patients with Tako-Tsubo cardiomyopathy

Background

An association between Tako-Tsubo cardiomyopathy (TTC) and underlying malignancies has been observed, suggesting that TTC might be the consequence of paraneoplastic phenomena. This study investigates the presence of autoantibodies against cardiomyocytes as well as adrenergic (β₁, β₂) and muscarinic (M2) receptors in patients with TTC.

Human interleukin 7 is a B cell growth factor for activated B cells

We investigated the capacity of human interleukin (IL) 7 to induce proliferation of B cells. Purified tonsillar B cells were cultured in the presence of IL7 with Staphylococcus aureus Cowan I (SAC) or anti-μ beads as co-mitogens. IL 7 supported a dose-dependent proliferation of anti-μ-activated B cells but did not significantly support proliferation of SAC-activated B cells. When B cells were separated on Percoll gradient into small (60%-80%) and large (50%–60%) B cells and then cultured with anti-μ beads, IL7 acted on both cell populations equally well. IL7 and BCGF (low molecular weight) were synergistic in their proliferative action on anti-μ-activated B cells in a 5-day culture. On the other hand, synergistic effect of IL 7 on activated B cells was not evident in the presence of any other factor recombinant [(r)IL 1β, rIL2, rIL3, rIL4, rIL5, rIL6, recombinant tumor necrosis factor-α, recombinant lymphotoxin, recombinant granulocyte-monocyte colony-stimulating factor and recombinant interferon-γ] we tested. IL7 did not induce IgG secretion by activated B cells.     

Paraoxonase 1 status in the Thai population

Human serum paraoxonase 1 (PON1), a high-density lipoprotein (HDL)-associated enzyme, has been shown to reduce the oxidation of low-density lipoprotein (LDL) and HDL by degrading lipid peroxides. This property of PON1 accounts for its ability to protect against atherosclerosis. In this study, we identified four polymorphisms in both the coding (L55M and Q192R) and regulatory regions (T-108C and G-909C) of the human PON1 gene in 202 healthy Thai individuals and investigated the influence of these polymorphisms on serum PON1 activity towards three substrates, namely, paraoxon, phenylacetate and diazoxon. The PON1 L55M, Q192R and G-909C polymorphisms significantly affected the variation in serum PON1 activity towards paraoxon. Serum PON1 activity towards paraoxon was significantly different among the genotype groups, as follows: 55LL > 55LM/55MM, 192RR > 192QR > 192QQ and –909CC > –909CG > –909GG. The PON1 Q192R and G-909C polymorphisms also influenced the variation in serum PON1 activity towards diazoxon but in the opposite direction to the activity towards paraoxon. Only the PON1 L55M polymorphism was associated with significant variation in serum PON1 activity towards phenylacetate while the PON1 T-108C polymorphism had no significant effect on serum PON1 activity towards any substrate. We also found linkage disequilibrium among the polymorphic sites, including Q192R versus L55M, Q192R versus T-108C and Q192R versus G-909C. Serum PON1 activity towards both paraoxon and phenylacetate, but not diazoxon, was positively correlated with HDL cholesterol (HDL-C) and apo AI concentrations. None of the PON1 polymorphisms significantly affected serum lipid, lipoprotein or apolipoprotein concentrations. Our findings suggest that the physiological relevance of the PON1 polymorphisms is that they are associated with significant differences in serum PON1 activity, and the impact of PON1 polymorphisms on this activity is substrate-dependent.     

Application of Microalgal Physiological Response as Biomarker for Evaluating the Toxicity of the Textile Dye Alizarin Red S

Textile dyes are becoming a growing threat to the environment. This report presents the findings of the study on the toxicity of the textile dye Alizarin Red S on two freshwater microalgae. The acute toxicity assay revealed that 96-h EC₅₀ values of Chlorella vulgaris and Spirulina platensis were 29.81 mg/L and 18.94 mg/L respectively. The pigments chlorophyll-a, b and carotenoids in C. vulgaris on 96-h exposure to the dye were 2.91, 3.29 and 3.01 times lower in analogy to control whereas Spirulina platensis showed 2.89and 2.56 fold decrease in chlorophyll-a and carotenoid content than control. After the test period of 96-h with dye, the protein content of C. vulgaris and S. platensis were 2.33 and 1.77 times lower compared to the control. The growth inhibition rate, pigment as well as the protein content declined in compliance with the rise in dye concentration, which anticipate paradigm about the toxic effects of the textile dye.

     

Induction of cell cycle arrest and apoptosis by the proteasome inhibitor PS-341 in Hodgkin disease cell lines is independent of inhibitor of nuclear factor-kappaB mutations or activation of the CD30, CD40, and RANK receptors.

PURPOSE: The malignant Hodgkin and Reed-Sternberg cells of Hodgkin disease (HD) are known to constitutively express high levels of activated nuclear factor kappaB (NF-kappaB), which plays an important role in their survival. The proteasome inhibitor PS-341 has been recently shown to modulate tumor cell proliferation and survival by inhibiting NF-kappaB and modulating critical cellular regulatory proteins, but its activity in cells carrying IkappaBalpha gene mutations has not been reported previously. Experimental Design: The activity of PS-341 in four well-characterized, HD-derived cell lines. Cell proliferation and apoptosis were determined by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfonyl)-2H-tetrazolium (MTS) and Annexin-V binding methods, respectively. Cell cycle analysis was determined by flow cytometry. Intracellular protein levels were determined by Western blot. RESULTS: PS-341 demonstrated a strong antiproliferative activity, which was irrespective of the status of mutations in IkappaBalpha and even the presence of CD30, CD40, or RANK receptor activation. This effect was attributable to the induction of apoptosis and cell cycle arrest at the G(2)-M phase. PS-341 not only inhibited nuclear localization of NF-kappaB but also activated the caspase cascade, increased p21 and Bax levels, and decreased Bcl-2 levels. Furthermore, PS-341 enhanced the effect of gemcitabine chemotherapy and potentiated the effect of tumor necrosis factor-related apoptosis-inducing ligand/APO2L and two agonistic antibodies to tumor necrosis factor-related apoptosis-inducing ligand death receptors R1 and R2. CONCLUSIONS: The in vitro activity of PS-341 against HD-derived cell lines suggests that PS-341 may have a therapeutic value for the treatment of HD.     

Safety,tolerability, and effectiveness of oral zonisamide therapy in comparison with intramuscular adrenocorticotropic hormone therapy in infants with West syndrome

West syndrome is a distinct, infantile onset, epileptic encephalopathy, associated with poor neurodevelopmental outcome. The present study was designed as a randomized, open-label, pilot study to evaluate the safety, feasibility, and effectiveness of oral zonisamide therapy in comparison with adrenocorticotropic hormone therapy in infants with West syndrome. Thirty infants with West syndrome were randomized to receive treatment with either synthetic, intramuscular adrenocorticotropic hormone (30–60 IU) or oral zonisamide (4–25 mg/kg/day). The study participants had a long treatment lag and preponderance of male sex (90%). The primary effectiveness outcome measure was the cessation of epileptic spasms at 2 weeks of initiation of therapy and persistent till 6 weeks as per West Delphi consensus statement recommendations. Comparison of efficacies of zonisamide versus adrenocorticotropic hormone was as following: the cessation of epileptic spasms (27% vs. 40%, p = 0.70), resolution of hypsarrhythmia at 14 days (20% vs. 33%, p = 0.68) and resolution of hypsarrhythmia at 6 weeks (36% vs. 71%, p = 0.14). Overall, the study observed a poor efficacy of both adrenocorticotropic hormone and zonisamide therapy, which is probably due to long treatment lag and a high proportion of structural aetiology. However, oral zonisamide appeared to be safe and tolerable in the study.