Biomedical subjects

K J Kennedy

Publications and source records attributed to K J Kennedy.

4 recordsLinked to original sources

PubMed1992

Reductive dehalogenation of chlorophenols by Desulfomonile tiedjei DCB-1.

Reductive dehalogenation of chlorophenols has been reported in undefined anaerobic cultures but never before in an anaerobic pure culture. We found that the sulfate-reducing bacterium Desulfomonile tiedjei DCB-1 reductively dehalogenates pentachlorophenol (PCP) and other chlorophenols. The maximum rate of PCP dechlorination observed was 54 mu mol of Cl- h-1 g of protein-1. 3-Chlorobenzoate appeared to serve as a required inducer for PCP dehalogenation; however, neither PCP nor 3-chlorophenol induced dehalogenation. Dehalogenation was catalyzed by living cells, and formate served as a required electron donor. D. tiedjei dehalogenated meta-chlorine substituents of chlorophenols (i.e., PCP was degraded to 2,4,6-trichlorophenol). Generally, more highly chlorinated phenol congeners were more readily dechlorinated, and 3-chlorophenol was not dehalogenated. Growing cultures dehalogenated PCP, but greater than 10 microM PCP (approximately 1.7 mmol g of protein-1) reversibly inhibited growth.

Bacteria, Anaerobic↗

PubMed1992

Limited degradation of chlorophenols by anaerobic sludge granules.

To better understand the fate of chlorophenols treated in upflow anaerobic sludge bed reactors, we examined the ability of sludge granules from such bioreactors to degrade two trichlorophenols and one dichlorophenol in batch incubations under controlled conditions. Biodegradation was primarily limited to two distinct activities, reductive dehalogenation of ortho- and of meta-chlorine substituents. Both 3- and 4-monochlorophenol were persistent degradation products, while 2-monochlorophenol was further degraded. We also examined factors potentially affecting the rate and extent of 2,3,6-trichlorophenol degradation. An initial concentration of up to 1.75 mM (346 mg/liter) was dehalogenated. At that concentration, dehalogenation was partially inhibited but methanogenesis from formate was not. The initial concentration affected both the extent of dehalogenation and which products were detected. The maximum dechlorination rate observed was 1.4 mumol of Cl- h-1 g of volatile suspended solids-1. Dechlorination had a temperature optimum of 50 degrees C, was inhibited by added electron acceptors, and was not appreciably affected by added electron donors. The availability of electron acceptors and electron donors did not affect the extent of chlorophenol degradation. These particular sludge granules do not appear to be capable of mineralizing phenols with meta- or para-chlorine substituents.

Anaerobiosis↗

PubMed1991

Diazepam and intubation in emergency treatment of seizures in children.

STUDY OBJECTIVES: This study was undertaken to determine the incidence of endotracheal intubation after the use of diazepam compared with phenobarbital or phenytoin in emergency treatment of seizures in children. DESIGN: The records of all children (98) were reviewed in a case-control fashion. A logistic regression model was used to determine whether there was an association between diazepam administration and intubation, adjusting for all other covariates (age, weight, convulsion time before first anticonvulsant was given, response latency, diagnosis, and therapy). SETTING: All children were treated in an emergency department and then transported to a tertiary pediatric center by a pediatric transport team. TYPE OF PARTICIPANTS: All patients were children, with a median age of 2.7 years (range 0.17 to 15.3 years). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Only the use of diazepam was found to be significantly associated with intubation after adjusting for all other covariates (adjusted odds ratio, 49.4; P less than .001). In the comparison of diazepam versus phenobarbital or phenytoin used as the first anticonvulsant, median response latency did not differ (27.0 vs 32.5 minutes, P greater than .83). CONCLUSION: A significant association was found between diazepam use and intubation. Response latency was not shorter when diazepam was used as the initial anticonvulsant compared with phenobarbital or phenytoin.

Adolescent↗

PubMed1981

Age effects on Trail Making Test performance.

The Trail Making Test, used in differentiating brain-damaged from non-brain-damaged individuals, was administered to 150 non-brain-damaged subjects classified into five age decades to determine the effects of age on performance. Between-group comparisons as well as correlational data indicated that older subjects performed significantly more poorly than younger subjects. Significant small negative correlations of performance with education and intelligence suggested that lower intelligence and education also may adversely affect performance. Some implications of these findings for clinical neuropsychology are discussed.

Adult↗