An evaluation of a model ecosystem with DDT

The reproducibility, variability, and reliability of a simple aquatic-terrtestrial model ecosystem experiment was tested with p,p'-DDT. The variation among the model replicates as well as within the units was studied by using hierarchal analysis of variance. the complete budget of the chemical was calculated and a theoretical transport model was constructed. The degradation and accumulation of DDT was followed by gas chromatographic residue analysis, which showed good reproducibility of the experimental design. The degradation of DDT in the model was similar to that found in the field, but the determination of concentration factors was questionable. The material balance tables revealed that the soil and bottom substrates were the main contributors, which regulated the fate of the chemical in the model. The usefulness of the model is presented in this report.     

Phase II trial of docetaxel: a new, highly effective antineoplastic agent in the management of patients with anthracycline-resistant metastatic breast cancer

PURPOSE: To determine the efficacy (objective response rate and duration of response and survival) and toxicity of docetaxel in patients with strictly defined anthracycline-resistant metastatic breast cancer (MBC). PATIENTS AND METHODS: Thirty-five patients with bidimensionally measurable MBC who had progressive disease while receiving anthracycline-containing chemotherapy were registered onto the phase II trial. Docetaxel was administered at a dose of 100 mg/m2 over 1 hour every 21 days. RESULTS: Thirty-four patients were assessable for disease response; 18 (53%; 95% confidence interval [CI], 35% to 70%) achieved a partial response. The median times to disease progression and survival duration were 7.5 and 13.5 months, respectively, for responding patients. The median overall survival duration was 9 months. Two hundred eight cycles (median, five) of docetaxel were administered. Neutropenia with less than 500 cells/microL developed in 31 of 35 patients; it was complicated by fever in 30 (14%) of 208 cycles and in 18 (51%) of 35 patients, including one treatment-related death. Fluid retention was seen in 15 (43%) of 35 patients, including pleural effusions in 11 patients (31%). Moderate skin toxicity, asthenia, and myalgia were observed in 16%, 58%, and 37% of cycles, respectively. CONCLUSION: Docetaxel has the highest reported antitumor activity in anthracycline-resistant MBC. High objective response rates were seen in patients with visceral-dominant involvement, multiple metastatic sites, or extensive previous therapy. Docetaxel is associated with severe but reversible neutropenia, asthenia, and cumulative dose-related fluid retention. Dexamethasone decreased the frequency and severity of skin toxicity and appeared to ameliorate fluid retention.     

Diuretics and diabetes mellitus

The term "diuretics" describes a concerning pharmacological action and side effects heterogeneous class of drugs. The special advantage of using diuretics includes reducing edema and expanded plasma volume often associated with hypertension and cardiovascular disease. Diuretics are one of the 5 major classes of antihypertensive agents recommended for the initial drug therapy of hypertension. However, currently treatment of hypertension with diuretics is controversial, because of potentially adverse effects on the cardiovascular risk profile, including deterioration in glucose control especially in patients with impaired glucose tolerance. Additionally there is concern about excess mortality associated with diuretic therapy and diabetes mellitus. The metabolic side effects on glucose metabolism and lipid profile are related to the type of diuretic and its dosage. The adverse effects of thiazides on insulin action, glycemia and lipid profile are dose dependent and can be minimized by using low doses. In contrast, indapamide seems not to alter glucose metabolism and lipid profile. The choice of diuretic depends on concomitant disease. In patients with nephropathy potassium sparing agents should not be used, however furosemid can be used even in high doses. Beside focus on indication of diuretics in patients with diabetes and their metabolic side effects treatment of therapy resistant hypertension in these patients are discussed in this review.     

二维平面有限单元法在坝体渗流稳定评价中的应用——以赤泥堆场4~#坝北坝段渗流稳定分析评价为例

中铝贵州分公司赤泥堆场4#坝为库中坝,坝为赤泥堆砌而成,其北坝段位于二叠系茅口组、龙潭组交接地段附近,随着该坝的不断加高使用,对该坝北段的渗流稳定进行了分析,其间用到的一些计算方法值得借鉴。     

光学旋光法的血糖浓度测量

采用光学法检测血糖浓度是现今国际研究的热门课题,目的是实现对糖尿病患者进行快速、无创、频繁、实时的血糖监测。本文介绍了光学旋光法检测血糖浓度的原理,对基于光学旋光法进行无创血糖检测技术的研究状况进行综述,讨论了各测量法的优缺点。     

超滤运行过程中膜表面亲水性的变化特征

为了研究膜亲水性在超滤运行过程中的变化规律,采用小试装置,研究了在不同运行状况下的膜接触角变化。结果表明,在长期的运行过程中,膜接触角均不同程度地下降。单独水反冲洗和化学加强反洗对接触角的影响较小。膜接触角在过滤周期内先升高再降低。随着通量的增加,膜接触角逐渐降低。与沉后水相比,活性炭过滤出水更易引起膜接触角下降。随着pH升高,膜接触角会上升。化学清洗使膜接触角增加,当用NaOH清洗时,接触角变化不大;而用HCl和NaClO清洗时,接触角明显增加。总之,膜表面亲水性在运行过程中会发生一定变化,并且受到原水水质、操作参数和反冲洗方式等方面影响。     

Uniparental disomy for chromosome 6 results in steroid 21-hydroxylase deficiency: evidence of different genetic mechanisms involved in the production of the disease

Congenital adrenal hyperplasia (CAH) is an inherited recessive disorder of adrenal steroidogenesis caused by mutations in the steroid 21-hydroxylase gene (CYP21) in more than 90% of affected patients. The CYP21 gene is located within the HLA complex locus on chromosome 6 (6p21.3). During a molecular characterisation study of a group of 47 Mexican families with 21-hydroxylase deficiency, we identified nine in which the mutation or mutations found in the patient did not appear to originate from one of the parents. Through DNA fingerprinting, paternity was established in all nine families with a probability of non-paternity in the range of 10(-19) to 10(-23). Among these families, we identified one patient with exclusive paternal inheritance of all eight markers tested on chromosome 6p, despite normal maternal and paternal contributions for eight additional markers on three different chromosomes. We did not identify duplication of paternal information for markers in the 6q region, consistent with lack of expression of transient neonatal diabetes owing to genomic imprinting in this patient. Our results substantiate evidence for the existence of different genetic mechanisms involved in the expression of this recessive condition in a substantial portion (approximately 19%) of affected Mexican families. In addition to the identification of a patient with paternal uniparental disomy, the occurrence of germline mutations may explain the unusual pattern of segregation in the majority of the remaining eight families.     

In situ analysis of adhesion molecule expression in kidneys infected with murine malaria

Two toluene-sensitive mutants were generated from Pseudomonas putida IH-2000, the first known toluene-tolerant isolate, by Tn5 transposon mutagenesis. These mutants were unable to grow in the presence of toluene (log P(ow) 2.8) but they could grow in medium overlaid with organic solvents having a log P(ow) value higher than that of toluene such as p-xylene (log P(ow) 3.1), cyclohexane (log P(ow) 3.4) and n-hexane (log P(ow) 3.9). The Tn5 transposable element knocked out a cyoB-like gene in one mutant and a cyoC-like gene in the other mutant. Seven open reading frames were found in a 5.5-kb region containing the cyoB- and cyoC-like genes of strain IH-2000. ORFs 3.7 showed significant identity to the cyoABCDE gene products of Escherichia coli, but ORFs 1 and 2 showed no significant homology to any protein reported so far. The growth patterns of the Tn5 mutants with the inactivated cyo-like gene were similar to that of the wild-type strain in the absence of organic solvents, although the doubling times were slightly longer than that of the wild-type strain. Our findings indicate that cyo is an important gene for toluene tolerance, although its role is still unclear.