Enhanced cytotoxicity of rituximab following genetic and biochemical disruption of glycosylphosphatidylinositol anchored proteins

Rituximab, an anti-CD20 monoclonal antibody used to treat B cell lymphoproliferative disorders and autoimmune diseases, kills cells through complement dependent cytotoxicity, antibody-dependent cellular toxicity and apoptosis. A mechanism of resistance to rituximab is upregulation of the complement regulatory proteins, CD59 and CD55. Paroxysmal nocturnal hemoglobinuria (PNH) is a hematopoietic disorder caused by PIGA mutations that lead to a loss of all glycosylphospatidylinositol (GPI)-anchored proteins including, CD55 and CD59. We compared the cytotoxic activity of rituximab against a PNH B cell line, LD -, and the isogenic cell line LD - PIGA + in which GPI-anchor expression was restored by stable transfection of PIGA. The PNH cell line was more sensitive to rituximab-mediated killing than the LD - PIGA + cells. Biochemical disruption of GPI anchors with phosphatidylinositol specific phospholipase C (PIPLC), a phospholipase that cleaves GPI-anchored proteins, also increased rituximab-mediated killing. Thus, genetic and biochemical interruption of GPI anchor proteins augments sensitivity to rituximab.     

Prospective comparative study of the safety and effectiveness of ginger for the treatment of nausea and vomiting in pregnancy

OBJECTIVES: The primary objective of our study was to examine the safety and the secondary objective was to examine the effectiveness of ginger for nausea and vomiting of pregnancy (NVP). STUDY DESIGN: Pregnant women who called the Motherisk Program who were taking ginger during the first trimester of pregnancy were enrolled in the study. The women were compared with a group of women who were exposed to nonteratogenic drugs that were not antiemetic medications. The women were followed up to ascertain the outcome of the pregnancy and the health of their infants. They were also asked on a scale of 0 to 10 how effective the ginger was for their symptoms of NVP. RESULTS: We were able to ascertain the outcome of 187 pregnancies. There were 181 live births, 2 stillbirths, 3 spontaneous abortions, and 1 therapeutic abortion. The mean birth weight was 3542+/-543 g, the mean gestational age was 39+/-2 weeks, and there were three major malformations. There were no statistical differences in the outcomes between the ginger group and the comparison group with the exception of more infants weighing less than 2500 g in the comparison group (12 vs 3, P < or =.001). There were a total of 66 completed effectiveness scores with the mean score of 3.3+/-2.9 SD. CONCLUSION: These results suggest that ginger does not appear to increase the rates of major malformations above the baseline rate of 1% to 3% and that it has a mild effect in the treatment of NVP.     

Enhanced erythrocyte adhesiveness/aggregation in obesity corresponds to low-grade inflammation

OBJECTIVE: Previous studies have suggested that obesity enhances the inflammatory response, producing macromolecules involved in the induction and/or maintenance of increased erythrocyte aggregation. The objectives of this study were to evaluate the correlation between inflammation markers, erythrocyte adhesiveness/aggregation, and the degree of obesity and to assess phosphatidylserine expression on erythrocyte surface membrane of obese vs. nonobese individuals. RESEARCH METHODS AND PROCEDURES: Erythrocyte adhesiveness/aggregation in the peripheral venous blood was evaluated by using a new biomarker, phosphatidylserine expression was assessed by means of flow cytometry, and markers of inflammation were measured in 65 subjects: 30 obese [body mass index (BMI) = 41 +/- 7.7 kg/m(2)] and 35 nonobese (BMI = 24 +/- 2.7 kg/m(2)) individuals. Pearson correlations and Student's t test were performed. RESULTS: A highly significant difference was noted in the degree of erythrocyte adhesiveness/aggregation and markers of inflammation between the study groups. BMI correlated with erythrocyte adhesiveness/aggregation (r = 0.42, p = 0.001), erythrocyte sedimentation rate (r = 0.42, p = 0.001), high-sensitive C-reactive protein (r = 0.55, p < 10(-4)), fibrinogen (r = 0.37, p = 0.004), and white blood cell count (r = 0.45, p < 10(-4)). The degree of erythrocyte adhesiveness/aggregation correlated with erythrocyte sedimentation rate (r = 0.5, p < 10(-4)), high-sensitive C-reactive protein (r = 0.56, p < 10(-4)), fibrinogen (r = 0.54, p < 10(-4)), and white blood cell count (r = 0.32, p = 0.01). DISCUSSION: Our results suggest that obesity-related erythrocyte adhesiveness/aggregation is probably mediated through increased concentrations of adhesive macromolecules in the circulation and not necessarily through hyperlipidemia or phosphatidylserine exposure on erythrocyte's membrane.     

Critical elements in the design of culturally appropriate interventions intended to reduce health disparities: immunization rates among Hispanic seniors in New Mexico

The importance of immunization in protecting seniors against influenza and pneumonia has long been recognized. Nevertheless, immunization rates among Medicare beneficiaries continue to fall short of what is both desirable and achievable. The problem is even more acute among certain racial and ethnic groups in the United States within which rates are below the rate for the country as a whole. This is true in New Mexico where 40 percent of the population is estimated to be Hispanic. As part of its work on behalf of the Centers for Medicare & Medicaid Services (CMS), the New Mexico Medical Review Association (NMMRA) undertook a project aimed both at reducing the disparities that exist in immunization status between the Hispanic and non-Hispanic population in the state and attempting to increase overall rates in the state for all groups. Developing interventions to reduce disparaties in immunization rates between Hispanic seniors and the rest of the senior population requires more than a straightforward review of the literature and must take into account not only the cultural differences that exist between Hispanics and non-Hispanics but, certainly, in the case of New Mexico, it must attempt to understand the richness and diversity that exists within the Hispanic communities across the state. To do otherwise runs the risk of designing interventions that are at best ineffective and at worst culturally insensitive and potentially damaging to future efforts to improve health status. This article describes the process undertaken by NMMRA, a Medicare Quality Improvement Organization (QIO), to collect qualitative data from three culturally different groups of Hispanics in New Mexico. The data are used to design interventions that will increase immunization rates for all Hispanics in New Mexico.     

The influence of anticonvulsant and antioxidant drugs on nitric oxide level and lipid peroxidation in the rat brain during penthylenetetrazole-induced epileptiform model seizures

Nitric oxide (NO) generation in the brain cortex of Wistar rats was measured by direct method of electron paramagnetic resonance (EPR) spectroscopy. Dramatic (fivefold) elevation of NO production was found during penthylenetetrazole (PTZ)-induced epileptiform seizures. The level of secondary products of lipid peroxidation (LPO; thiobarbituric acid reactive substances, TBARS) was also significantly increased in the cerebral cortex of rats with PTZ-evoked seizures. The effects of anticonvulsant drugs phenobarbital, lamotrigine, phenazepam, as well as antioxidant substances alpha-tocopherol and novel original Russian synthetic drug mexidol (2-ethyl-6-methyl-3-oxypiridine succinate), were investigated. All the substances studied significantly decreased seizure manifestations and partially prevented both enhancement of NO generation and increase in TBARS formation. Mexidol and phenobarbital were found to be the most effective in the preventing of PTZ-induced seizures among all the substances studied. The data obtained support our speculation that neuroprotective action of mexidol may correlate with its ability to inhibit not only excessive reactive oxygen species (ROS) formation but also NO generation. While the molecular mechanism underlying action of mexidol and phenobarbital still remains unclear, it is likely that the effect of these drugs on NO production is contributing to their neuroprotective action. It might be concluded that both the suppression of seizure-induced NO generation and LPO enhancement may be involved in the mechanism of action of antiepileptic drugs.     

Tropomyosin isoforms from the gamma gene differing at the C-terminus are spatially and developmentally regulated in the brain

Tropomyosin is an actin-binding protein responsible for stabilizing the actin microfilament system in the cytoskeleton of nonmuscle cells and is involved in processes such as growth, differentiation, and polarity of neuronal cells. From the gamma gene, at least 11 different isoforms have been described, with three different C-terminal exons used (9a, 9c, 9d). The precise roles that the different isoforms play are unknown. To examine the localization and hence determine the function of these isoforms in developing mouse, specific antibodies to exons 9a and 9c were made. These were used with previously developed 9d and N-terminal 1b antibodies on Western blots and immunohistochemical analysis of mouse brains. We were able to show that all three C-termini are used in the brain. 9c isoforms are highly enriched in brain and neural cells, and we also detected significant amounts of 9a-containing isoforms in brain. gamma gene activity is relatively constant in the brain, but the choice of C-terminus is developmentally regulated. A more detailed study of the brain revealed regional expression differences. The hippocampus, cerebellum, and cortex were analyzed in depth and revealed that different isoforms could be sorted into different neuronal compartments, which change with development for 9d. Furthermore, a comparison with a homologous exon to 9c from the alpha-tropomyosin gene showed that expression from these exons is related to the maturational state of the neuron, even though both are sorted differently intracellularly. These data suggest that the large numbers of tropomyosin isoforms are likely to have specific roles in microfilament dynamics and neural cell function.     

TRPV6 is not required for 1α,25-dihydroxyvitamin D3-induced intestinal calcium absorption in vivo

The requirement for TRPV6 for vitamin D-dependent intestinal calcium absorption in vivo has been examined by using vitamin D-deficient TRPV6 null mice and littermate wild-type mice. Each of the vitamin D-deficient animals received each day for 4 days 50 ng of 1,25-dihydroyvitamin D₃ in 0.1 ml of 95% propylene glycol:5% ethanol vehicle or vehicle only. Both the wild-type and TRPV6 null mice responded equally well to 1,25-dihydroxyvitamin D₃ in increasing intestinal calcium absorption. These results, along with our microarray data, demonstrate that TRPV6 is not required for vitamin D-induced intestinal calcium absorption and may not carry out a significant role in this process. These and previous results using calbindin D9k null mutant mice illustrate that molecular events in the intestinal calcium absorption process in response to the active form of vitamin D remain to be defined.