A semi-automated method for measuring the potential for protein covalent binding in drug discovery

INTRODUCTION: Covalent protein binding of metabolically reactive intermediates of drugs has been implicated in drug toxicity including the occurrence of idiosyncratic drug toxicity. Investigators therefore would prefer to avoid developing compounds that produce significant amounts of reactive metabolites. By incubating the radiolabeled drug of interest with liver microsomes it is possible to evaluate the propensity of a drug candidate to covalently bind to proteins. METHODS: Here we present a semi-automated method in which a Brandel cell harvester is used to collect and wash proteins that have been incubated with radiolabeled drug. This method utilizes glass fiber filter paper to capture precipitated protein, rather than the more traditional exhaustive extraction/centrifugation approach. Using model compounds (including [14C]diclofenac, [3H]imipramine, [14C]naphthalene, and [14C]L-746530) we compare the covalent binding results obtained using this method to results generated using the traditional method and we performed cross-laboratory testing of assay reproducibility. RESULTS: It was found that results from new method correlated highly with the traditional method (R2=0.89). The cross-laboratory testing of the method showed an average interlaboratory coefficient of variation of only 18.4%. DISCUSSION: This method provides comparable results to the more traditional centrifugation-based method with considerable time and labor savings.     

The Temporal and Spatial Variations of Acid Aerosols in the GeothermalArea of Metropolitan Taipei, Taiwan

This study involved sampling over 1 year of data on exposure to acid aerosols in the geothermal area of metropolitan Taipei. The temporal and spatial variations of the concentrations of acid aerosols were assessed by sampling at three sites: A, B, and C. Results indicate that the SO₂ concentrations lead the concentrations of other acid aerosols at site C because two active fumaroles surround this site. The mean SO₂ concentrations at sites A, B, and C were 2.4, 2.4, and 6.2 ppb. Previous studies have found that H₂S levels were highest at site C. However, the SO₄⁻² and H⁺ concentrations among the three sites were similar. The mean aerosol SO₄⁻² concentrations were 7.0, 5.7, and 5.7 μg m⁻³ at sites A, B, and C, respectively; their H⁺ concentrations were 5.5, 4.2, and 5.4 nmolm⁻³. No seasonal variations are observed for most of the acid aerosols in the geothermal area except that the types of hot spring affect the SO₄⁻² concentration nearby. The different seasonal fluctuation among the sites reflect the determinant of SO₄⁻² emission from different geothermal sources. Sulfur-rich aerosols and some SO₂ emitted from geothermal sources are obvious. The predominance of nitrogen-containing gases (sum of NO₂ + HNO₂ + HNO₃) over SO₂ indicates the importance of the anthropogenic origin of emissions. The effect of multiple exposures to sulfur-rich aerosol (including H₂S, SO₂, and SO₄⁻²), H⁺, and nitrogen-containing aerosols on the health of nearby residents warrants concern.     

Decrease in anogenital distance among male infants with prenatal phthalate exposure

Prenatal phthalate exposure impairs testicular function and shortens anogenital distance (AGD) in male rodents. We present data from the first study to examine AGD and other genital measurements in relation to prenatal phthalate exposure in humans. A standardized measure of AGD was obtained in 134 boys 2-36 months of age. AGD was significantly correlated with penile volume (R = 0.27, p = 0.001) and the proportion of boys with incomplete testicular descent (R = 0.20, p = 0.02). We defined the anogenital index (AGI) as AGD divided by weight at examination [AGI = AGD/weight (mm/kg)] and calculated the age-adjusted AGI by regression analysis. We examined nine phthalate monoester metabolites, measured in prenatal urine samples, as predictors of age-adjusted AGI in regression and categorical analyses that included all participants with prenatal urine samples (n = 85). Urinary concentrations of four phthalate metabolites [monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP), and monoisobutyl phthalate (MiBP)] were inversely related to AGI. After adjusting for age at examination, p-values for regression coefficients ranged from 0.007 to 0.097. Comparing boys with prenatal MBP concentration in the highest quartile with those in the lowest quartile, the odds ratio for a shorter than expected AGI was 10.2 (95% confidence interval, 2.5 to 42.2). The corresponding odds ratios for MEP, MBzP, and MiBP were 4.7, 3.8, and 9.1, respectively (all p-values < 0.05). We defined a summary phthalate score to quantify joint exposure to these four phthalate metabolites. The age-adjusted AGI decreased significantly with increasing phthalate score (p-value for slope = 0.009). The associations between male genital development and phthalate exposure seen here are consistent with the phthalate-related syndrome of incomplete virilization that has been reported in prenatally exposed rodents. The median concentrations of phthalate metabolites that are associated with short AGI and incomplete testicular descent are below those found in one-quarter of the female population of the United States, based on a nationwide sample. These data support the hypothesis that prenatal phthalate exposure at environmental levels can adversely affect male reproductive development in humans.     

Perceptions regarding preventive sexual practices and communication with sexual partners among Chinese college students

PURPOSE: To assess the relation between Chinese college students' perceptions and attitudes regarding preventive sexual behaviors, their sexual knowledge, and their use of protective sexual behaviors. METHODS: A subsample of 133 sexually active college students (18-25 years old) was obtained to identify factors related to protective sexual behaviors (e.g., knowledge of partner's sexual history, condom use). RESULTS: Seventy-five percent of the sexually active students were male. Significantly more females had discussed AIDS and sexually transmitted diseases (STDs) issues with their partners and had asked their partners about their sexual histories than males. Students endorsing the use of preventive behaviors were more likely to have discussed AIDS issues with their partners, used condoms, and known their partner's sexual history. CONCLUSIONS: Student perceptions about preventive behaviors have a significant impact on their knowledge of their sexual partners and their own sexual behaviors. These findings, as well as the presence of significant gender differences in perceptions and communications with their partners, have major implications for risk reduction programs.     

Comparison of coronary artery calcium screening image quality between C-150 and e-Speed electron beam scanners

RATIONALE AND OBJECTIVE: The newest generation of electron beam tomographic scanner (e-Speed) has increased spatial and temporal resolution compared with the C-150 XP scanner. The aim of this study was to evaluate coronary artery calcium screening image quality between the e-Speed and C-150 scanners (GE Imatron, San Francisco, CA). MATERIALS AND METHODS: Studies from 41 patients (14 women and 27 men) who underwent serial coronary artery calcium screening with the C-150 (first study) and the e-Speed (second study) were analyzed. Individual computed tomography (CT) slices were assessed for coronary artery motion artifacts, and CT Hounsfield units (HU) and noise values (CT HU standard deviation) at 16 discrete cardiac sites were measured and averaged. RESULTS: With the e-Speed scanner, there were significant decreases in right coronary artery motion artifacts compared with the C-150 scanner (0.3% versus 1.8%, P < .001) as well as decreased noise values (24.3 versus 32.0 HU, P < .001). CONCLUSION: Image quality is significantly improved with use of the e-Speed scanner, due to its improved temporal and spatial resolution, compared with the C-150 scanner.     

Magnetic resonance diffusion-weighted imaging in the diagnosis of diffuse liver diseases in rats

Background The diagnosis of diffuse hepatic lesions in early stage is a tough task at any time for clinical conventional imaging. Magnetic resonance diffusion-weighted imaging (MR DWI) can detect the changes of tissue structure at molecular level. This study was designed to determine the value of DWI in the diagnosis of diffuse liver lesions in early stage.
Methods Diffuse liver lesions were induced by diethylnitrosamine in 42 rats of test group. Fourteen rats in control group were fed with pure water. Dynamic changes of MR DWI were observed every week in both groups during the early stage of diffuse liver lesions (1 to 12 weeks after drug administration in the test group). Apparent diffusion coefficient (ADC) values of liver parenchyma in different stages and pathologic changes were analyzed.
Results The process of diffuse hepatic lesions in the test group was classified into three stages according to pathological changes, namely hepatitis, hepatic fibrosis and cirrhosis. No obvious morphological changes were shown by conventional imaging in both groups during this stage. But MR DWI demonstrated heterogeneous signal changes in early stage of hepatic cirrhosis in the test group. No significant change of ADC values was found in the control group between different weeks (P>0.05). The ADC values of the test group declined from the fifth week, and after the tenth week the ADC values were significantly different between the test and control groups at gradient factor (b) value 300 sec/mm2 (P<0.05). At b value 600 and 1000 sec/mm2, significant difference was seen between the two groups from the sixth week onward. The range of ADC value of the groups was (1.7-0.9)±(0.40-0.04) mm2/sec (b=600) and (1.38-0.75)±(0.07-0.35) mm2/sec (b=1000), respectively. Dominant pathological changes included swelled hepatocytes within 1 to 4 weeks after the administration of diethylnitrosamine in the test group, hyperplasia of fibrous tissues in 5-8 weeks and formation of cirrhotic nodules in 9-12 weeks.
Conclusions MR functional DWI could detect diffuse liver lesions earlier than conventional morphological imaging. ADC value as a marker for early diagnosis of diffuse liver lesions could also be used to inspect changes of the lesions.
     

供、受者细胞因子及其受体单核苷酸多态性对肾移植近期急性排斥反应的影响

目的研究肾移植供受者的细胞因子和细胞因子受体单核苷酸多态性对术后早期移植物急性排斥反应的影响。方法（1）根据有无急性排斥发生,129例肾移植受者分成急性排斥组和无排斥组（6个月内）,根据HIJA—A—B—DR错配、神经钙蛋白抑制剂、肾功能延迟恢复、ATG或MAb诱导治疗、冷缺血时间等情况,对两组患者进行比较,并比较两组5种细胞岗子及5种受体的21个位点的基因型分布情况。（2）根据HLA—DR配型情况分成0～1个HLADR位点错配组（0—1MM）、HLA—DR完全错配组（2MM）,比较两组基因多态性的分布情况。结果（1）129例肾移植受者中,39例（30．2％）发生急性排斥反应。（2）急性排斥组HLA—DR错配数和无排斥组中差异有统计学意义（P〈0．05）。（3）细胞因子和细胞因子受体位点的多态性在急性排斥组和无排斥组中的分布有明显不同,差异有统计学意义。（4）HIA—DR完全错配组（2MM组）和0～1个位点错配组（0～1MM组）进行比较,两者多态性分布亦有不同。结论肾移植供受者不同基因多态性对预测排斥的发生有指导意义。     

老年髋部骨折的牵引治疗

目的了解因全身其他因素,不能接受手术治疗的老年髋部骨折患者,进行牵引治疗的结果。方法2000年11月至2005年1月共有102例老年髋部骨折患者,因伴有心脏病、糖尿病、高血压等内科疾病而行牵引治疗。其中股骨颈骨折37例,股骨粗隆间骨折65例,年龄48～98岁,平均75．8岁。所有病例均在家中接受牵引治疗。结果1年内死亡9例,死亡率8．8％（9／102）。其他并发症依次为褥疮30例,发生率29．4％（30／102）,肺部感染6例,发生率5．9％（6／102）,下肢深静脉血栓2例,肺栓塞1例,泌尿系感染1例。股骨颈骨折愈合15例,愈合率51．7％（15／29）。股骨粗隆间骨折愈合40例,愈合率97．6％（40／41）。调查时与伤前Harris评分比较,股骨颈骨折组平均下降23．1分,股骨粗隆间骨折组下降15．6分。结论对于无移位或稳定的股骨颈骨折,以及部分粗隆间骨折,牵引治疗可以获得良好的结果,且其花费低,在现阶段仍具有一定的适用范围。     

Persistent efficacy of live attenuated hepatitis A vaccine (H2-strain) after a mass vaccination program

Background Live attenuated hepatitis A vaccine （ H2 strain） is widely applied in prevention of hepatitis A epidemic in China and other countries now. It is essential to observe and confirm the vaccine immune efficacy, population antibody level and its persistent efficacy after mass immunization. Methods A total of 220 children with negative anti-HAV antibody （ aged 1-3 years） were taken for follow-up assay to observe seroconversion and geometric mean titre（GMT） level 2 months, 12 months, 6 years, and 10 years after inoculation. Another survey sampled from subjects of different age groups （3, 6, 9, 15, 18, 25 and 35 years） to compare anti-HA antibody positive rate before and after inoculation performed 10 years previously. Epidemiological observations were taken for 10 years to evaluate the relationship between vaccine coverage and hepatitis A morbidity. Serum antibody to HAV was detected by enzyme linked immunoassay （ELISA, calibrated by WHO international reference） and ABBOTY Axsym HAVAB microparticle enzyme immunoassay. Results Seroconversion in follow-up assay 2 months and 10 years after inoculation was 98.6% and 80. 2% respectively. For children, the vaccination anti-HA antibody positive rates were significantly different before and after 10 years, 7.69% cf 70.45% （aged 3 years） and 52. 58% cf 71.78% （aged 18 years）. When vaccine coverage rose from 57% to 74%, there were no any HA epidemics. When vaccine coverage reached 85%, there were no any HA cases. With vaccine coverage between 85% and 91%, there were no any HA cases in cohorts from the age of 1 year to 15 years during the 10 years. Conclusions Live attenuated hepatitis A vaccine has an obvious long-term effectiveness in prevention and control of HA epidemics through mass vaccination.