Gestational exposure to chlorpyrifos: dose response profiles for cholinesterase and carboxylesterase activity

This study investigates the in vivo dose response profiles of the target enzyme cholinesterase (ChE) and the detoxifying enzymes carboxylesterase (CaE) in the fetal and maternal compartments of pregnant rats dosed with chlorpyrifos [(O,O'-diethyl O-3,5,6-trichloro- 2-pyridyl) phosphorothionate], a commonly used organophosphorus insecticide. Pregnant rats were dosed daily (po) with chlorpyrifos in corn oil (0, 3, 5, 7, or 10 mg/kg) on gestational days (GD) 14-18. Animals were sacrificed 5 h after the last chlorpyrifos dose (time of maximum brain cholinesterase inhibition) for analysis of ChE and CaE activity in maternal blood, liver, brain, placenta, and fetal liver and brain. The in vitro sensitivity (i.e., IC50, 30 min, 26 degrees C) of CaE also was determined by assaying the activity remaining after incubation with a range of chlorpyrifos-oxon concentrations. In vivo exposure to 10 mg/kg chlorpyrifos from GD14-18 caused overt maternal toxicity, with dose-related decreases in ChE activity more notable in maternal brain than fetal brain. Dose-related effects were also seen with chlorpyrifos-induced inhibition of fetal liver ChE and maternal brain CaE activities. Gestational exposure caused no inhibition of placental ChE or CaE, fetal brain CaE, or maternal blood CaE. ChE activities in the maternal blood and liver, as well as fetal and maternal liver CaE, however, were maximally inhibited by even the lowest dosage of chlorpyrifos. The in vitro sensitivity profiles of CaE to chlorpyrifos-oxon inhibition were valuable in predicting and verifying the in vivo CaE response profiles. Both the in vivo and in vitro findings indicated that fetal liver CaE inhibition was an extremely sensitive indicator of fetal chlorpyrifos exposure.      

A randomized double-blind, placebo-controlled trial of the EMLA® patch for the reduction of pain associated with intramuscular injection in four to six-year-old children

The effectiveness of a eutectic mixture lidocaine-prilocaine topical anaesthetic cream (EMLA) patch compared with a placebo patch in the reduction of pain associated with intramuscular immunization was evaluated. As part of the study, 161 children (aged 4-6-y) undergoing routine diphtheria, pertussis, tetanus and polio (DPTP) immunization in five urban and five rural private office settings were randomly assigned to an EMLA patch (n = 83) or a placebo patch control group (n = 78). Pain measurements included: child's self-report on a Faces Pain Scale; facial action on the Child Facial Coding System; the Children's Hospital of Eastern Ontario Pain Scale and parent and technician ratings on a Visual Analogue Scale. Parents also rated their own and their child's immunization-related anxiety on a Visual Analogue Scale. The EMLA patch group had significantly less pain on all four pain measures compared with the placebo group. Of the children in the placebo group, 43% had clinically significant pain, compared with 17% of children in the EMLA patch group. No severe adverse symptoms occurred as a result of either EMLA or placebo patch application. CONCLUSION: The EMLA patch reduced immunization pain in 4 to 6-y-old children during needle injection.     

A contrast correction method for dental images based on histogram registration

Contrast correction is often required in digital subtraction radiography when comparing medical data acquired over different time periods owing to dissimilarities in the acquisition process. This paper focuses on dental radiographs and introduces a novel approach for correcting the contrast in dental image pairs.The proposed method modifies the subject images by applying typical registration techniques on their histograms. The proposed histogram registration method reshapes the histograms of the two subject images in such a way that these images are matched in terms of their contrast deviation. The method was extensively tested over 4 sets of dental images, consisting of 72 registered dental image pairs with unknown contrast differences as well as 20 dental pairs with known contrast differences. The proposed method was directly compared against the well-known histogram-based contrast correction method.The two methods were qualitatively and quantitatively evaluated for all 92 available dental image pairs. The two methods were compared in terms of the contrast root mean square difference between the reference image and the corrected image in each case. The obtained results were also verified statistically using appropriate t-tests in each set.The proposed method exhibited superior performance compared with the well-established method, in terms of the contrast root mean square difference between the reference and the corrected images. After suitable statistical analysis, it was deduced that the performance advantage of the proposed approach was statistically significant.     

自身免疫性肝炎大鼠模型外周血淋巴细胞体外培养与褪黑素的影响

目的:观察褪黑素对体外培养淋巴细胞增殖及促进细胞因子分泌的作用。方法:实验于2004-10/2006-10在解放军第一二三医院南京军区肝病中心实验室完成。①实验材料:Wistar大鼠,雄性,3月龄,体质量(230±20)g,购自上海斯莱克实验动物有限责任公司。褪黑素:美国Sigma公司产品。②实验方法:采用弗氏完全佐剂加肝细胞特异性脂蛋白法建立自身免疫性肝炎大鼠模型。分别抽取正常大鼠及模型大鼠的外周血,实验室常规培养,并将其分为3组:褪黑素组培养基中加褪黑素使终浓度为2mg/L;促肝细胞生长素组培养基中加促肝细胞生长素使终浓度为2mg/L;空白对照组培养基中不加任何细胞分裂刺激剂。③实验评估:培养48h后,对外周血淋巴细胞进行常规计数并采用液体闪烁计数仪记录1min计数结果值。用于观察褪黑素与促肝细胞生长素促进外周血淋巴细胞增殖的效果。并检测培养上清液中的各细胞因子浓度,用于观察褪黑素与促肝细胞生长素促进外周血淋巴细胞分泌细胞因子的作用。结果:①褪黑素对正常大鼠外周血淋巴细胞有促进增殖作用,细胞数与1min计数值较空白对照组明显升高(P<0.05),促肝细胞生长素无促进外周血淋巴细胞增殖作用。②褪黑素对模型大鼠外周血淋巴细胞有促进增殖作用,细胞数与1min计数值较空白对照组明显升高(P<0.05),促肝细胞生长素无促进外周血淋巴细胞增殖作用。③在褪黑素作用下,正常大鼠Th1细胞因子IL-2和IFN-γ水平明显高于空白对照组和促肝细胞生长素组(P<0.01),Th2细胞因子IL-6明显升高(P<0.05),IL-4水平与空白对照组比较,差异不显著(P>0.05),促肝细胞生长素组Th1和Th2细胞因子与空白对照组无明显差异(P>0.05)。④在褪黑素作用下,模型大鼠Th1细胞因子IL-2和IFN-γ水平较空白对照和促肝细胞生长素组明显升高(P<0.05),Th2细胞因子IL-4和IL-6水平与空白对照和促肝细胞生长素组无明显差异(P>0.05)。结论:褪黑素对自身免疫性肝炎大鼠外周血淋巴细胞有较强的刺激分裂作用。     

Chloramphenicol-dependent antibody: a case report

BACKGROUND: Chloramphenicol-dependent antibodies are a rare cause of interference in pretransfusion serologic testing. Their presence can be confirmed by the testing of red cells in both the presence and absence of chloramphenicol. CASE REPORT: A 29-year-old, group A, Rh-positive man with no history of chloramphenicol exposure was found to have a chloramphenicol-dependent panagglutinin in his serum. The antibody was IgM with a titer of 8. It showed no blood group specificity when tested with common and rare red cell phenotypes, and it failed to react with platelets and granulocytes. Confirmation attempts using a chloramphenicol sodium succinate solution as the cell-suspending medium led to negative results. The antibody reacted serologically only in the presence of chloramphenicol, which arises from the succinate derivative by the action of blood esterases. CONCLUSION: This case is an additional example of a chloramphenicol-dependent antibody. It demonstrates how the laboratory investigation of drug-related phenomena is dependent on testing the drug from that reacts in vivo.     

Improvement in lipids after switch to boosted atazanavir or darunavir in children/adolescents with perinatally acquired HIV on older protease inhibitors: results from the Pediatric HIV/AIDS Cohort Study

Objectives

Dyslipidaemia is common in perinatally HIV‐infected (PHIV) youth receiving protease inhibitors (PIs). Few studies have evaluated longitudinal lipid changes in PHIV youth after switch to newer PIs.

Methods

We compared longitudinal changes in fasting lipids [total cholesterol (TC), triglycerides (TG), low‐density lipoprotein cholesterol (LDL‐C), high‐density lipoprotein cholesterol (HDL‐C), and TC:HDL‐C ratio] in PHIV youth enrolled in the Pediatric HIV/AIDS Cohort Study (PHACS) Adolescent Master Protocol (AMP) study who switched to atazanavir/ritonavir (ATV/r)‐ or darunavir/ritonavir (DRV/r)‐based antiretroviral therapy (ART) from an older PI‐based ART and those remaining on an older PI. Generalized estimating equation models were fitted to assess the association of a switch to ATV/r‐ or DRV/r‐based ART with the rate of change in lipids, adjusted for potential confounders.

Results

From 2007 to 2014, 47 PHIV children/adolescents switched to ATV/r or DRV/r, while 120 remained on an older PI [primarily lopinavir/r (72%) and nelfinavir (24%)]. Baseline age ranged from 7 to 21 years. After adjustment for age, Tanner stage, race/ethnicity, and HIV RNA level, a switch to ATV/r or DRV/r was associated with a more rapid annual rate of decline in the ratio of TC:HDL‐C. (β = ?0.12; P = 0.039) than remaining on an older PI. On average, TC declined by 4.57 mg/dL/year (P = 0.057) more in the switch group. A switch to ATV/r or DRV/r was not associated with the rate of HDL‐C, LDL‐C, or TG change.

Conclusions

A switch to ATV/r or DRV/r may result in more rapid reduction in TC and the TC:HDL‐C ratio in PHIV youth, potentially impacting long‐term cardiovascular disease risk.

     

Clinical features and predictors of diphtheritic cardiomyopathy in Vietnamese children

BACKGROUND: Despite the availability of antitoxin and antibiotics, the mortality rate for diphtheria remains high, mostly because of cardiac complications. METHODS: During 1 year, 154 Vietnamese children with diphtheria admitted to a referral hospital were studied prospectively with clinical examination, including a simple pseudomembrane score, 12-lead and 24-hour electrocardiography, measurement of serum cardiac enzyme levels, and estimation of troponin T levels. RESULTS: Thirteen children had diphtheritic cardiomyopathy on admission, and 19 developed it subsequently. Twelve children (8%) died. The combination of pseudomembrane score of >2 and bull neck predicted the development of diphtheritic cardiomyopathy, with a positive predictive value of 83% and a negative predictive value of 93%. Administration of 24-hour electrocardiography on admission improved the ability to predict diphtheritic cardiomyopathy by 57%. Fatal outcome was best predicted by the combination of myocarditis on admission and a pseudomembrane score of >2. Of the cardiac enzyme levels measured, an elevated aspartate aminotransferase level was the best predictor. The presence of troponin T identified additional children with subclinical cardiac damage. CONCLUSIONS: The development of diphtheritic cardiomyopathy can be predicted by means of simple measures.     

Complement-induced vesiculation and exposure of membrane prothrombinase sites in platelets of paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired stem-cell disorder in which the glycolipid-anchored membrane proteins, including the cell-surface complement inhibitors, CD55 and CD59, are partially or completely deleted from the plasma membranes of mature blood cells. To gain insight into the pathogenesis of thrombosis that is frequently observed in this disorder, the procoagulant responses of PNH platelets exposed to the human terminal complement proteins C5b-9 were investigated. C5b-9 complexes were assembled on gel-filtered platelets by incubation with purified C5b6, C7, C9, and limiting amounts of C8. Platelet microparticle formation and exposure of plasma membrane- binding sites for coagulation factor Va were then analyzed by flow cytometry. PNH platelets exhibiting undetectable levels of surface CD59 antigen showed an approximately 10-fold increase in sensitivity to C5b- 9-stimulated expression of membrane-binding sites for factor Va when compared with platelets from normal controls. Expression of catalytic surface for the prothrombinase complex (VaXa) paralleled the exposure of factor Va-binding sites; the rate of prothrombin conversion by C5b-9- treated PNH platelets exceeded that of C5b-9-treated normal controls by approximately 10-fold at the maximal input of C8 tested (500 ng/mL). These data indicate that PNH platelets deficient in plasma membrane CD59 antigen are exquisitely sensitive to C5b-9-induced expression of prothrombinase activity, and suggest that the tendency toward thrombosis in these patients may be due, at least in part, to the deletion of this complement inhibitor from the platelet plasma membrane.     

去糖基化突变体肾素元的分子特点

应用野生体和去糖基化突变体肾素元ｃＤＮＡ，转染ＧＨ４细胞，经３５Ｓ代谢标记表达产物，免疫沉淀，ＳＤＳ／ＰＡＧＥ电泳检测观察去糖基后肾素元结构与功能的变化．发现去糖基化后的肾素元突变体，除半衰期缩短外，其分子粘度明显增高，转染细胞清除作为代谢标记去糖基化肾素元的时间延长。说明肾素元的糖基化的对其分子不仅在自稳中起重要作用，同时在成熟中可能也有重要生物学意义。