Characterization and degradation mechanism of a newly isolated hydrolyzed polyacrylamide-degrading bacterium Alcaligenes faecalis EPDB-5 from the oilfield sludge.

Hydrolyzed polyacrylamide (HPAM) is posing serious threats to ecosystems. However, biodegradation is an effective method to remove HPAM owing to its low cost and environmental friendliness. In this study, Alcaligenes faecalis EPDB-5 was isolated as a highly efficient HPAM degrading strain from sludge contaminated with polymerized produced water from Daqing oilfield.

Teaching substance abuse screening, assessment, and brief intervention to vocational rehabilitation counselors.

Vocational rehabilitation counselors are in key positions to screen clients for alcohol and drug abuse. An educational program improved counselors understanding of this process.

Tolerance and physical dependence to a short-acting benzodiazepine, midazolam.

Midazolam is a new ultra short-acting benzodiazepine whose physical dependence properties have not been well characterized. Our laboratory has demonstrated previously that physical dependence to the long-acting chlordiazepoxide in the rat is inducible by a single intoxicating dose, whereas maximal dependence required chronically equivalent maximally tolerable dosing b.i.

Pharmacologic characterization of acute chlordiazepoxide dependence in the rat.

A single intoxicating dose of chlordiazepoxide HCl (p.o.) in the rat can induce quantifiable manifestations of physical dependence.

Benzodiazepine tolerance, physical dependence and withdrawal: electrophysiological study of spinal reflex function.

The in situ segmental spinal reflex system of the rat was used to determine changes in excitatory and inhibitory synaptic function associated with benzodiazepine tolerance, physical dependence and withdrawal. Rats were made physically dependent on chlordiazepoxide using a chronically equivalent dosing method. After spinalization, dorsal and ventral lumbar roots (L5 or L6) were isolated for extracellular stimulation and recording.

Phenobarbital tolerance and physical dependence: chronically equivalent dosing model.

A rat model of phenobarbital tolerance and physical dependence has been developed based on the 'maximally tolerable, chronically equivalent' dosing paradigm. Sodium phenobarbital was administered orally twice daily for 35 days in individually adjusted doses to achieve mean daily peak CNS depression culminating in severe ataxia. Dose to dose continuity of CNS depression was maintained throughout treatment.

Experimental induction of benzodiazepine tolerance and physical dependence.

To initiate studies of benzodiazepine tolerance and physical dependence, a reproducible animal model has been developed utilizing chlordiazepoxide in rats. Based on the "chronically equivalent" dosing principle, a regimen has been devised to maintain rats in a state of quantifiable intoxication for 5 weeks. Chlordiazepoxide was delivered intragastrically on a b.

Physical dependence to barbital compared to pentobarbital. IV. Influence of elimination kinetics.

The withdrawal characteristics of barbital and pentobarbital after "chronically equivalent" treatment suggested that the longer acting barbital was less liable to produce physical dependence. Therefore, to distinguish this potential pharmacodynamic difference from the known pharmacokinetic differences between the two drugs, the rate of elimination of each was adjusted to mimic that of the other. The rate of barbiturate elimination after chronically equivalent pentobarbital dosing was reduced by barbital substitution or by first-order pentobarbital dose reduction, with the result that withdrawal signs became mild and appeared later (3 days postdrug).

Physical dependence to barbital compared to pentobarbital. III. Withdrawal characteristics.

After "chronically equivalent" barbital and pentobarbital dosing for 5 weeks, treatments were abruptly stopped and the animals were carefully observed for signs of barbiturate withdrawal. The severity of withdrawal was assessed at preset times by counting the number of grand mal type convulsions and subjectively rating 20 additional motor, autonomic and behavioral signs including tremors, twitches, myoclonic jerks, postural disturbances and motor incoordination. Ratings achieved at peak intensity (raw scores) and their incidences were used to compute "total intensity scores" for each graded sign.

Physical dependence to barbital compared to pentobarbital. II. Tolerance characteristics.

This study describes the tolerance characteristics of barbital compared to pentobarbital, the standard drug, during "chronically equivalent" treatment. Barbiturate tolerance was assessed as the increase in dose from the beginning to the end of treatment required to achieve equieffective peak effect. Dispositional tolerance was assessed as a reduction in the elimination half-life of barbiturate from blood.

Evaluation of anticonvulsants in barbiturate withdrawal.

Four prototypic anticonvulsants were tested for their effectiveness against barbiturate withdrawal in cats. The effects were evaluated on a total of over 20 motor, autonomic and behavioral withdrawal signs. The animals were made physically dependent by 5 weeks of twice daily "maximally tolerable" sodium pentobarbital dosing intragastrically.

Withdrawal characteristics following chronic pentobarbital dosing.

Experiments were performed to provide a quantitative description of the barbiturate withdrawal syndrome. Physical dependence was produced in 63 cats by 'maximally tolerable' dosing with sodium pentobarbital. After 5 weeks of chronic treatment each animal was placed in an activity monitoring cage and observed closely for signs of barbiturate abstinence.

Effect of chronic pentobarbital treatment on blood-cerebrospinal fluid kinetics.

Cats were made tolerant and physically dependent by twice daily equieffective anesthetic dosing with sodium pentobarbital intragastrically for 5 weeks. Serial blood and CSF samples were simultaneously collected on day 1 and day 35 and analyzed for pentobarbital by a gas chromatographic method. Pentobarbital penetration into CSF was rapid and unchanged by chronic treatment.

Tolerance characteristics produced during the maximally tolerable chronic pentobarbital dosing in the cat.

The method of "maximally tolerable" dosing technique for establishing a reproducible state of barbiturate dependence in cats was used for the study. The development of tolerance in animals treated by this method has been quantitatively assessed. Sodium pentobarbital was administered morning and evening for 35 days via a plastic tube implanted into the stomach through the abdominal wall.