Transplacental IgG Subclass Concentrations in Pregnancies at Risk of Haemolytic Disease of the Newborn

The relationship of haemolytic disease of the newborn (HDN) to the transplacental passage of the four IgG subclasses was assessed at varous gestational ages by comparing the maternal and fetal IgG subclass concentrations in 34 pregnancies at risk of HDN with those in 30 pregnancies not at risk. Higher maternal and fetal IgG1 levels were attained in pregnancies at risk of HDN than in pregnancies not at risk. In contrast, a slight decrease in maternal IgG2 and IgG4 levels occurred in pregnancies at risk of HDN, as compared with a slight rise in maternal IgG2 and IgG4 levels in pregnancies not at risk of HDN. Changes in fetal IgG2 and 4 concentrations in either type of pregnancy were very similar, showing only slight increases between the 19th and 34th week of gestation. A slight decrease in maternal IgG3 occurred in both types of pregnancy. In contrast, higher and fairly steady levels of fetal IgG3 were observed in fetuses not at risk of HDN throughout gestation, when compared with those in 'at risk' pregnancies. However, the statistical reliability of these results is not clear since only small numbers of samples were tested and because wide variations in IgG concentrations were observed. The IgG subclass concentrations in 50 paired maternal and cord blood samples were also measured and revealed that IgG1 levels were substantially higher in cord rather than maternal blood; cord and maternal IgG2, 3 and 4 levels, on the other hand, were fairly similar.     

Effects of hydro-ethanolic extract of leaves of Maesa lanceolata (Mursinaceae) on acetic acid-induced ulcerative colitis in rats

Inflammopharmacology - Ulcerative colitis is a form of inflammatory bowel disease that is characterized by acute and chronic inflammation. The aim of this work was to evaluate the efficacy of...     

Collective many-body van der Waals interactions in molecular systems

Van der Waals (vdW) interactions are ubiquitous in molecules and condensed matter, and play a crucial role in determining the structure, stability, and function for a wide variety of systems. The accurate prediction of these interactions from first principles is a substantial challenge because they are inherently quantum mechanical phenomena that arise from correlations between many electrons within a given molecular system. We introduce an efficient method that accurately describes the nonadditive many-body vdW energy contributions arising from interactions that cannot be modeled by an effective pairwise approach, and demonstrate that such contributions can significantly exceed the energy of thermal fluctuations-a critical accuracy threshold highly coveted during molecular simulations-in the prediction of several relevant properties. Cases studied include the binding affinity of ellipticine, a DNA-intercalating anticancer agent, the relative energetics between the A- and B-conformations of DNA, and the thermodynamic stability among competing paracetamol molecular crystal polymorphs. Our findings suggest that inclusion of the many-body vdW energy is essential for achieving chemical accuracy and therefore must be accounted for in molecular simulations.     

An open-label, sequential, dose-finding study of peginesatide for the maintenance treatment of anemia in chronic hemodialysis patients

ABSTRACT: BACKGROUND: Peginesatide is a peptide-based erythropoiesis-stimulating agent that was designed and engineered to stimulate specifically the erythropoietin receptor dimer that governs erythropoiesis. The primary objective of this phase 2 dose-finding study was to determine the once-monthly peginesatide dosing strategy that would maintain hemoglobin within [PLUS-MINUS SIGN]1.0 g/dL of baseline values after conversion from epoetin alfa; the safety of peginesatide was evaluated concurrently. METHODS: Chronic hemodialysis patients on stable regimens of epoetin alfa were sequentially assigned to cohorts that differed on (1) how the peginesatide starting dose was determined (using a single epoetin alfa--to-peginesatide dose conversion ratio or a tiered, weight-based or absolute-dose conversion table) and on (2) whether or not a 1-week erythropoiesis-stimulating agent-free interval was used. Peginesatide doses were titrated to maintain hemoglobin levels within [PLUS-MINUS SIGN]1.0 g/dL from baseline. RESULTS: A total of 164 patients were enrolled and received intravenous peginesatide every 4 weeks for up to 6 doses; the duration of the study including follow-up was [LESS-THAN OR EQUAL TO]29 weeks. Overall, the proportion of patients with hemoglobin levels within [PLUS-MINUS SIGN]1.0 g/dL of baseline increased over the course of the study from 39% (Weeks 2--13) to 54% (Weeks 18--25). Cohorts that used tiered dose conversion tables trended towards having more stable peginesatide doses than did those cohorts that used a single dose conversion ratio. Moreover, cohorts that used an erythropoiesis-stimulating agent-free interval did not have the substantial initial increase in hemoglobin levels that was seen in those cohorts that did not use such an interval. In this study, the safety profile of peginesatide was consistent with those of marketed erythropoiesis-stimulating agents. CONCLUSIONS: The results of this study were used to guide the dosing regimens used subsequently in phase 3 studies. Once-monthly peginesatide is feasible in hemodialysis patients.Trial registrationClinicalTrials.gov registration: NCT00228449.     

Greater Epoetin alfa Responsiveness Is Associated With Improved Survival in Hemodialysis Patients

Background and objectives: Among hemodialysis patients, achieved hemoglobin is associated with Epoetin alfa dose and erythropoietin responsiveness. A prospective erythropoietin responsiveness measure was developed and its association with mortality evaluated.Design, setting, participants, & measurements: Data from 321 participants were used and randomized to the hematocrit normalization arm of the Normal Hematocrit Cardiac Trial. Subjects were to receive a 50% Epoetin alfa dose increase at randomization. The prospective erythropoietin responsiveness measure was defined as the ratio of weekly hematocrit change (over the 3 wk after randomization) per Epoetin alfa dose increase (1000 IU/wk) corresponding to the mandated 50% dose increase at randomization. The distribution of responsiveness was divided into quartiles. Over a 1-yr follow-up, Cox proportional hazard modeling evaluated associations between this responsiveness measure and mortality.Results: Erythropoietin responsiveness values ranged from −2.1% to 2.4% per week per 1000 IU. Although subjects were similar across response quartiles, mortality ranged between 14% and 34% among subjects in the highest and lowest response quartiles (P = 0.0004), respectively. After adjusting for baseline prognostic indicators, highest versus lowest responsiveness was associated with a hazard ratio of 0.41 (95% confidence interval, 0.20 to 0.87).Conclusion: Lower erythropoietin responsiveness is a strong, independent predictor of mortality risk and should be considered when evaluating associations between clinical outcomes and potential prognostic indicators, such as Epoetin alfa dose and achieved hemoglobin values.More than 90% of end-stage renal disease patients require exogenous erythropoietin or transfusion to achieve and maintain target hemoglobin values (1,2) because of decreased endogenous erythropoietin production. The ability to achieve and maintain target hemoglobin levels is complicated by a variety of mediating factors that impact responsiveness to erythropoietin, including comorbidities, inflammation, and malnutrition. These factors are independently associated with poor clinical outcomes (3–9).The impact of erythropoietin responsiveness on mortality is not well understood. Although higher hemoglobin levels have been associated with reduction in mortality in observational studies (10,11), evidence from randomized clinical trials of hemodialysis patients does not suggest a mortality benefit (12). Paradoxically, in the Normal Hematocrit Cardiac Trial (13), the largest randomized trial conducted to date in hemodialysis patients, survival rates were higher among those achieving higher hematocrit values, but targeting a higher hematocrit was associated with a 1.3-fold increased risk of mortality or nonfatal myocardial infarction (95% confidence interval [CI], 0.9 to 1.9). This suggests that unknown/unmeasured patient characteristics associated with the ability to achieve greater hemoglobin values may confound analyses assessing mortality risks among dialysis patients.Achieved hemoglobin level is associated with both the Epoetin alfa doses administered and patient responsiveness to erythropoietin. Greater survival among patients with higher hemoglobin values may be partly due to greater erythropoietin responsiveness (14) in addition to a direct result of anemia correction. Likewise, lower survival among those with lower achieved hemoglobin values may be partly the result of lower relative erythropoietin responsiveness. Patients who require higher Epoetin alfa doses to achieve a given hemoglobin level, that is, who are less responsive to erythropoietin, may experience poorer outcomes at any achieved hemoglobin value (15).In this study, data from the hematocrit normalization arm of the Normal Hematocrit Cardiac Trial (13) were used to develop a prospective measure of erythropoietin responsiveness, which was then evaluated in relation to mortality.