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L Adrian

Publications and source records attributed to L Adrian.

8 recordsLinked to original sources
PubMed2001

Transformation of 2,2'-dichlorodiisopropyl ether in mixed and pure culture.

An aerobic enrichment culture derived from a groundwater contaminated with organic and chloroorganic compounds was adapted to the transformation of 2,2'-dichlorodiisopropyl ether (DDE) in a continuous fixed-bed bioreactor. Continuous DDE removal efficiencies over 90% were achieved with a model water containing 3.3 mM methanol as co-substrate at DDE loading rates of up to 150 micromol l(-1) day(-1) with a hydraulic retention time of 24 h. In batch cultures, a stoichiometric release of 2 micromol chloride per micromol DDE transformed was observed. From the mixed culture, a strain was isolated that is able to grow on DDE as the sole energy and carbon source, tolerating DDE concentrations of up to 1 mM. Based on 16S rRNA sequencing, the strain is affiliated with the genus Rhodococcus.

Aerobiosis↗
PubMed2000

Bacterial dehalorespiration with chlorinated benzenes.

Chlorobenzenes are toxic, highly persistent and ubiquitously distributed environmental contaminants that accumulate in the food chain. The only known microbial transformation of 1,2,3,5-tetrachlorobenzene (TeCB) and higher chlorinated benzenes is the reductive dechlorination to lower chlorinated benzenes under anaerobic conditions observed with mixed bacterial cultures. The lower chlorinated benzenes can subsequently be mineralized by aerobic bacteria. Here we describe the isolation of the oxygen-sensitive strain CBDB1, a pure culture capable of reductive dechlorination of chlorobenzenes. Strain CBDB1 is a highly specialized bacterium that stoichiometrically dechlorinates 1,2,3-trichlorobenzene (TCB), 1,2,4-TCB, 1,2,3,4-TeCB, 1,2,3,5-TeCB and 1,2,4,5-TeCB to dichlorobenzenes or 1,3,5-TCB. The presence of chlorobenzene as an electron acceptor and hydrogen as an electron donor is essential for growth, and indicates that strain CBDB1 meets its energy needs by a dehalorespiratory process. According to their 16S rRNA gene sequences, strain CBDB1, Dehalococcoides ethenogenes and several uncultivated bacteria form a new bacterial cluster, of which strain CBDB1 is the first, so far, to thrive on a purely synthetic medium.

Bacteria↗
PubMed2000

Bacterial growth based on reductive dechlorination of trichlorobenzenes.

An anaerobic mixed bacterial culture was enriched for bacteria dechlorinating 1,2,3- and 1,2,4-trichlorobenzene (TCB) to dichlorobenzenes by exclusive use of non-fermentable substrates and the application of vancomycin. Growth and dechlorination occurred in a purely synthetic medium with formate or hydrogen, acetate, and TCB. Neither acetogenesis nor methanogenesis was detected in the culture. Repeated subculturing maintaining high dechlorinating activities was also achieved when only hydrogen and TCB were supplied. This indicated that reductive dechlorination of TCB was the primary energy conservating process. The number of dechlorinating bacteria was strictly limited by the amount of TCB supplied in the medium. In addition, the dechlorinating activity could be maintained only in the presence of TCB. A most probable number analysis showed that the dechlorinating species amounted to at least 6 x 10(5) cells per ml at a total cell number of about 2 x 10(6) cells per ml. Vitamin B12 significantly stimulated the dechlorinating activity.

Anaerobiosis↗
PubMed1998

Physiological characterization of a bacterial consortium reductively dechlorinating 1,2,3- and 1,2,4-trichlorobenzene.

A bacterial mixed culture reductively dechlorinating trichlorobenzenes was established in a defined, synthetic mineral medium without any complex additions and with pyruvate as the carbon and energy source. The culture was maintained over 39 consecutive transfers of small inocula into fresh media, enriching the dechlorinating activity. In situ probing with fluorescence-labeled rRNA-targeted oligonucleotide probes revealed that two major subpopulations within the microbial consortium were phylogenetically affiliated with a sublineage within the Desulfovibrionaceae and the gamma subclass of Proteobacteria. The bacterial consortium grew by fermentation of pyruvate, forming acetate, propionate, CO2, formate, and hydrogen. Acetate and propionate supported neither the reduction of trichlorobenzenes nor the reduction of sulfate when sulfate was present. Hydrogen and formate were used for sulfate reduction to sulfide. Sulfate strongly inhibited the reductive dechlorination of trichlorobenzenes. However, when sulfate was depleted in the medium due to sulfate reduction, dechlorination of trichlorobenzenes started. Similar results were obtained when sulfite was present in the cultures. Molybdate at a concentration of 1 mM strongly inhibited the dechlorination of trichlorobenzenes. Cultures supplied with molybdate plus sulfate did not reduce sulfate, but dechlorination of trichlorobenzenes occurred. Supplementation of electron-depleted cultures with various electron sources demonstrated that formate was used as a direct electron donor for reductive dechlorination, whereas hydrogen was not.

Bacteria↗
PubMed1996

Brain relapses in chemotherapy-treated small cell lung cancer: a retrospective review of two time-dose regimens of therapeutic brain irradiation.

The incidence of brain metastases secondary to small cell lung cancer (SCLC) is about 35% and the treatment strategy of brain irradiation with respect to dose and fractionation is controversial. In order to evaluate treatment outcome of brain irradiation in SCLC patients with brain relapse, we retrospectively evaluated all patients treated with brain irradiation in the eastern part of Denmark from 1988 to 1992 (PCI patients excluded). During this 5-year period, 101 evaluable patients were included (44 females, 57 males) (median age 61 years; range, 39-75 years). Forty-four patients, of whom 43 were in extracerebral complete remission (CR), received extended course (EC) brain irradiation (> 45 Gy, treatment schedule > 4 weeks). Fifty-seven patients received short course (SC) brain irradiation (< 30 Gy, treatment schedule < 1 week). Among the SC treated patients, 14 were in CR, 20 had partial remission or stable disease and 23 had progressive extracerebral disease. The median survival (from diagnosis of brain metastases) in the group receiving irradiation with EC (44 patients) was 160 days (range, 74-2021 days), while the 57 patients treated with SC had a median survival of 88 days (range, 20-948 days) (P = 0.00001, Log-Rank analysis). In a subgroup of 14 patients in extracerebral CR, receiving SC irradiation, the median survival was 83 days (range, 15-948 days). When the latter patients were compared to the 43 patients in CR in the group treated with EC, a statistically significant difference was shown (P = 0.034, Log-Rank analysis). Using Cox-hazard regression analysis with backward elimination, liver metastases and poor performance status were adverse prognostic signs, although the only significant parameters of survival were gender (female vs. male, relative risk of dying 1 and 1.52, P = 0.05) and schedule of brain irradiation (extended course vs. short course, relative risk of dying, 0.36 and 1, P < 0.001). Extended course irradiation of brain relapse secondary to SCLC seems in general to be of limited value, although a significant prolonged survival at approximately 7 weeks, was obtained. The prolongation of survival does not seem worthwhile considering the length of treatment time (5-6 weeks) compared to SC treatment (1 week). However, the data do not permit evaluation of the quality of life of the patients. This retrospective evaluation suggests the need for randomized trials with carefully planned quality-of-life assessments.

Adult↗
PubMed1991

A regional prospective study of in-hospital mortality associated with coronary artery bypass grafting. The Northern New England Cardiovascular Disease Study Group.

OBJECTIVE: A prospective regional study was conducted to determine if the observed differences in in-hospital mortality rates associated with coronary artery bypass grafting (CABG) are solely the result of differences in patient case mix. DESIGN-Regional prospective cohort study. Data including patient demographic and historical data, body surface area, cardiac catheterization results, priority of surgery, comorbidity, and status at hospital discharge were collected. This study presents data for 3055 CABG patients between July 1, 1987, and April 15, 1989. SETTING: This study includes data from all surgeons performing cardiothoracic surgery in Maine, New Hampshire, and Vermont; the data were collected from five regional medical centers. PATIENTS: Data were collected from all consecutive isolated CABG surgery patients during the study period. MAIN OUTCOME MEASURES: Crude and adjusted in-hospital mortality rates associated with CABG. MAIN RESULTS: The overall crude in-hospital mortality rate for isolated CABG was 4.3%. The rate varied among centers (range, 3.1% to 6.3%) and among surgeons (range, 1.9% to 9.2%). Predictors of in-hospital mortality included increased age, female gender, small body surface area, greater comorbidity, reoperation, poorer cardiac function as indicated by a lower ejection fraction, increased left ventricular end diastolic pressure and emergent or urgent surgery. After adjusting for the effects of potentially confounding variables, substantial and statistically significant variability was observed among medical centers (P = .021) and among surgeons (P = .025). CONCLUSION: We conclude that the observed differences in in-hospital mortality rates among institutions and among surgeons in northern New England are not solely the result of differences in case mix as described by these variables and may reflect differences in currently unknown aspects of patient care. Understanding this variation requires a detailed understanding of the processes of care.

Adult↗