Beckman EL-ISE电解质分析仪准确性及故障的分析判断

0 引言为了克服离子选择电极（ISE）法的微量电位信号极易受环境温度变化及电子噪声的干扰问题,该仪器采用了参考电极,把参考电极与其测定电极装在同一测量室内,保持其相同的物理环境,使干扰源对所有电极的影响相同. 以内参液作为参考电极的测量对象,测得一个参考电极电位值,再测样品的电极电位值,二者相抵就消除了所叠加的干扰信号.     

How sociodemographics, presence of oncology specialists, and hospital cancer programs affect accrual to cancer treatment trials.

PURPOSE: We chose to examine the impact of socioeconomic factors on accrual to National Cancer Institute (NCI)-sponsored cancer treatment trials. PATIENTS AND METHODS: We estimated the geographic and demographic cancer burden in the United States and then identified 24,332 patients accrued to NCI-sponsored cancer treatment trials during a 12-month period. Next, we examined accrual by age, sex, geographic residence, health insurance status, health maintenance organization market penetration, several proxy measures of socioeconomic status, the availability of an oncologist, and the presence of a hospital with an approved multidisciplinary cancer program. RESULTS: Pediatric patients were accrued to clinical trials at high levels, whereas after adolescence, only a small percentage of cancer patients were enrolled onto clinical trials. There were few differences by sex. Black males as well as Asian-American and Hispanic adults were accrued to clinical trials at lower rates than white cancer patients of the same age. Overall, the highest observed accrual was in suburban counties. Compared with the United States population, patients enrolled onto clinical trials were significantly less likely to be uninsured and more like to have Medicare health insurance. Geographic areas with higher socioeconomic levels had higher levels of clinical trial accruals. The number of oncologists and the presence of approved cancer programs both were significantly associated with increased accrual to clinical trials. CONCLUSION: We must work to increase the number of adults who enroll onto trials, especially among the elderly. Ongoing partnership with professional societies may be an effective approach to strengthen accrual to clinical trials.     

The international collaborative study of maternal phenylketonuria: status report 1994

Neonatal screening for phenylketonuria (PKU) has created a problem as females with PKU are reaching child-bearing age. Surveys have revealed that maternal phenylalanine blood concentrations greater than 1200 μmol/l are associated with fetal microcephaly, congenital heart defects and intrauterine growth retardation. It is estimated that as many as 3000 hyperphenylalaninemic females may be at risk of producing these fetal abnormalities. To examine this problem, the international maternal PKU collaborative study was developed to evaluate the efficacy of a phenylalanine-restricted diet in reducing fetal morbidity. Preliminary findings have indicated that phenylalanine restriction should begin before conception for females with PKU planning a pregnancy. Dietary control should maintain maternal blood phenylalanine levels between 120 and 360 μmol/l and should provide adequate energy, protein, vitamin and mineral intake. Pregnant hyperphenylalaninemic females who achieved metabolic control after conception or by the 10th week of pregnancy had a better offspring outcome than anticipated. The results of 402 pregnancies are reviewed.     

HIV-1 diversity and prevalence differ between urban and rural areas in the Mbeya region of Tanzania

OBJECTIVE: To characterize HIV-1 strains in a potential vaccine trial cohort (CODE) in the Mbeya region of southwest Tanzania. DESIGN: Study volunteers (n = 3096) were recruited from urban areas in Mbeya Town, using two different recruitment strategies, and in a nearby rural village. METHODS: Cryopreserved plasma from 507 HIV-1 prevalent cases was the source of viral RNA for HIV-1 genotyping by the Multi-region Hybridization Assay, the MHA(acd), and selected strains were confirmed by complete genome sequencing. RESULTS: The overall HIV-1 prevalence was 16.6% [95% confidence interval (CI), 15.3-17.9] within the cohort. HIV-1 prevalence was higher among women, and in urban areas. Recruitment through advertisement targeted a high-risk urban male population for HIV-1 infection [adjusted odds ratio (adj. OR), 1.68; 95% CI, 1.13-2.51] when compared with men recruited door-to-door. The complexity of the HIV-1 epidemic was also higher in urban areas evidenced by the high-risk of HIV-1 infection with a recombinant strain (adj. OR, 2.69; 95% CI, 1.08-6.69) and HIV-1 dual infection (adj. OR, 5.16; 95% CI, 1.07-24.9), mainly driven by urban men recruited through advertisement. CONCLUSIONS: Overall the urban epidemic was more genetically complex, with higher prevalence and more recombinants and dual infections. Vaccine trials in Mbeya region can assess a complex HIV-1 population dynamic and determine vaccine efficacy in relationship to the genetic diversity of HIV-1 strains that challenge vaccines.