Interleukin-1 modulates GABAergic and glutamatergic function in brain

Interleukin-1 is a polypeptide cytokine involved in the acute-phase response. We examined the effects of IL-1 on the major inhibitory and excitatory neurotransmitter systems in brain mediated by GABA and glutamate, respectively. IL-1 enhanced the effects of GABA as determined by GABA-dependent chloride uptake at 1 and 10 ng/ml in cortical synaptoneurosomes. This effect was attenuated by pretreatment with the IL-1 receptor antagonist. Neither IL-6 nor TNF was effective in this system. IL-1 decreased the effect of NMDA and glycine on intracellular calcium concentrations in cultured chick cortical neurons in both the presence and absence of the endogenous polyamine spermine. This effect was attenuated by pretreatment with the AMPA/kainate antagonist CNQX. These data indicate that IL-1 modulates both inhibitory and excitatory neurotransmitter function in brain.

Degradation of methyl bromide by methanotrophic bacteria in cell suspensions and soils

Cell suspensions of Methylococcus capsulatus mineralized methyl bromide (MeBr), as evidence by its removal from the gas phase, the quantitative recovery of Br- in the spent medium, and the production of 14CO2 from [14C]MeBr. Methyl fluoride fluoride (MeF) inhibited oxidation of methane as well as that of [14C]MeBr. The rate of MeBr consumption by cells varied inversely with the supply of methane, which suggested a competitive relationship between these two substrates. However, MeBr did not support growth of the methanotroph. In soils exposed to high levels (10,000 ppm) of MeBr, methane oxidation was completely inhibited. At this concentration, MeBr removal rates were equivalent in killed and live controls, which indicated a chemical rather than biological removal reaction. At lower concentration (1,000 ppm) of MeBr, methanotrophs were active and MeBr consumption rates were 10-fold higher in live controls than in killed controls. Soils exposed to trace levels (10 ppm) of MeBr demonstrated complete consumption within 5 h of incubation, while controls inhibited with MeF or incubated without O2 had 50% lower removal rates. Aerobic soils oxidized [14C]MeBr to 14CO2, and MeF inhibited oxidation by 72%. Field experiments demonstrated slightly lower MeBr removal rates in chambers containing MeF than in chambers lacking MeF. Collectively, these results show that soil methanotrophic bacteria, as well as other microbes, can degrade MeBr present in the environment.

Interaction of central and peripheral benzodiazepine sites in benzodiazepine tolerance and discontinuation

1. Chronic administration of benzodiazepines is associated with the development of tolerance and discontinuation effects in humans and in a mouse model. 2. Co-administration of compounds active at the "peripheral" benzodiazepine site may alter chronic benzodiazepine effects. 3. During chronic lorazepam administration, addition of the peripheral site antagonist PK11195 attenuates behavioral tolerance and receptor downregulation. 4. In mice treated with both lorazepam and PK11195, discontinuation effects were also attenuated compared to lorazepam alone. 5. Specificity of the action of PK11195 was confirmed by antagonism of its action by the peripheral-site agonist Ro5-4864.

Isolation, Growth, and Metabolism of an Obligately Anaerobic, Selenate-Respiring Bacterium, Strain SES-3

A gram-negative, strictly anaerobic, motile vibrio was isolated from a selenate-respiring enrichment culture. The isolate, designated strain SES-3, grew by coupling the oxidation of lactate to acetate plus CO 2 with the concomitant reduction of selenate to selenite or of nitrate to ammonium. No growth was observed on sulfate or selenite, but cell suspensions readily reduced selenite to elemental selenium (Se 0 ). Hence, SES-3 can carry out a complete reduction of selenate to Se 0 . Washed cell suspensions of selenate-grown cells did not reduce nitrate, and nitrate-grown cells did not reduce selenate, indicating that these reductions are achieved by separate inducible enzyme systems. However, both nitrate-grown and selenate-grown cells have a constitutive ability to reduce selenite or nitrite. The oxidation of [ 14 C]lactate to 14 CO 2 coupled to the reduction of selenate or nitrate by cell suspensions was inhibited by CCCP (carbonyl cyanide m -chlorophenylhydrazone), cyanide, and azide. High concentrations of selenite (5 mM) were readily reduced to Se 0 by selenate-grown cells, but selenite appeared to block the synthesis of pyruvate dehydrogenase. Tracer experiments with [ 75 Se]selenite indicated that cell suspensions could achieve a rapid and quantitative reduction of selenite to Se 0 . This reduction was totally inhibited by sulfite, partially inhibited by selenate or nitrite, but unaffected by sulfate or nitrate. Cell suspensions could reduce thiosulfate, but not sulfite, to sulfide. These results suggest that reduction of selenite to Se 0 may proceed, in part, by some of the components of a dissimilatory system for sulfur oxyanions.

Acute effects of benzodiazepines on operant behavior and in vivo receptor binding in mice

Lorazepam and alprazolam produced dose-dependent decreases in the rate of fixed-ratio (FR) 20 schedules of food presentation in which either a nose-poke or a lever-press defined the operant and under a fixed-interval (FI) 2-min lever-press schedule of food presentation. In contrast, under FI 2-min and differential reinforcement of low response rate (DRL) 20-s schedules of nose-poke responding for food, intermediate doses of alprazolam produced increases in response rate. Lorazepam, however, only decreased overall response rates under the FI schedule and produced some increases in responding under the DRL schedule. Acute in vivo benzodiazepine receptor binding experiments showed that low to intermediate doses of alprazolam produced significant increases in the binding of [3H]flumazenil in all brain areas tested, while lorazepam produced increases in the brain stem only. The acute effects on binding produced by both drugs were positively and significantly correlated with their acute effects on response rate only under the FR lever-press procedure. These results indicate that the effects of benzodiazepines on in vivo binding may be related to their effects on FR lever-press responding.

Managing provider networks through expert systems: use of patterns of treatment to address overutilization

Among the most important contributors to rising health care costs is excess utilization of services. Sophisticated clinical criteria, encoded as an expert system in software, allow identification of probable excess utilization in large claims data sets. These systems can be used to adjudicate claims, resulting in direct cost savings, or to profile physicians and other providers, facilitating creation and maintenance of networks. These systems are used by traditional payers to promote quality, control costs, and enhance competitiveness and are beginning to be used by nontraditional payers, such as physician groups and hospital-based networks.

Isolation and characterization of the promoter of the human GABAA receptor alpha 1 subunit gene

The GABAA receptor, as assessed by ligand binding and chloride flux measurement in vivo and in vitro, is down-regulated in response to chronic benzodiazepine exposure. The mRNA levels of the alpha 1 and gamma 2 subunits of the receptor are also reduced. We have isolated the promoter of the gene encoding the alpha 1 subunit of the GABAA receptor to elucidate the regulatory mechanism of its expression. A DNA segment 650 bp long has been isolated that includes 151 bp of untranslated 5' end of the cDNA sequence and 500 bp of potential promoter-enhancer region. The transcriptional activity of this DNA segment linked to the firefly luciferase gene showed a strong orientation specificity. The promoter activity was localized to a 60-bp segment by deletion mapping. Mobility shift binding assay results suggest that this segment may interact with one or more factors in HeLa cell nuclear extracts to form a transcriptional complex. Primary cultures of embryonic chick cortical cells transfected with the promoter-luciferase construct were treated chronically with lorazepam. Transcriptional activity of this promoter construct was strongly repressed by chronic administration of lorazepam.

Application of actigraphy in the clinical setting: use in children with attention-deficit hyperactivity disorder

Clinicians rely primarily on subjective behavioral questionnaires in assessing attention-deficit hyperactivity disorder (ADHD). The new mini-motion logger actigraph, which is a wrist-worn minicomputer, can add an objective element to this assessment and is especially useful in children due to its small size. We applied this technology as an outcome measure in evaluating drug therapy in two children with ADHD who were receiving methylphenidate and pemoline, respectively. We also assessed preliminary findings from an additional 13 children.

Polyamine potentiation and inhibition of NMDA-mediated increases of intracellular free Ca2+ in cultured chick cortical neurons

Polyamine potentiation and inhibition of N-methyl-D-aspartate (NMDA) receptor-mediated Ca2+ changes was studied in cultured chick cortical neurons. Spermidine and spermine potentiated the effect of saturating concentrations of NMDA and glycine. No effect of spermidine or spermine was observed in the absence of NMDA or in the presence of either kainate or quisqualate. Similarly, antagonism of the NMDA receptor complex with dizocilpine (an open channel blocker), or with competitive antagonists to the NMDA or glycine binding sites greatly attenuated or completely abolished the combined effects of polyamines plus NMDA and glycine. N-Acetylspermine and N-acetylspermidine, in the presence or absence of NMDA and glycine, were without effect. These data strongly suggest that spermidine and spermine are potent and selective agonists at the polyamine binding site. Putrescine and diethylenetriamine were ineffective as antagonists of NMDA-mediated intracellular free Ca2+ increases in the presence or absence of added spermine or spermidine. Arcaine and 1,10-diaminodecane, however, antagonized NMDA-mediated intracellular free Ca2+ increases in the presence and absence of spermine and spermidine, and therefore appear to act either as inverse agonists at the polyamine binding site or as open channel blockers of the NMDA receptor.

Chronic cocaine administration is associated with behavioral sensitization and time-dependent changes in striatal dopamine transporter binding

Chronic cocaine administration has been associated with sensitization (an increase in drug effect) rather than the tolerance observed with many psychotropic compounds. Because cocaine acts at the presynaptic dopamine transporter, we evaluated sensitization and striatal dopamine transporter binding in vivo in several mouse strains. All strains of mice evaluated showed increased activity after cocaine compared with after saline injections. BALB/cByJ, DBA/2J, B6AF1/J and C57BL6/J mice exhibited sensitization when assayed 72 hr after five daily injections of cocaine at 20 and 40 mg/kg/day, whereas B6AF1/J mice showed sensitization at 20 but not at 40 mg/kg/day. CD-1 mice did not exhibit sensitization at either dose. Striatal dopamine transporter binding in vivo was increased in DBA/2J and B6AF1/J mice when determined 72 hr after five injections of 40 mg/kg/day cocaine. In contrast, a continuous infusion of cocaine at the same dose and duration did not produce sensitization or binding changes in DBA/2J mice. The time course of transporter binding alterations after intermittent cocaine exposure indicated no change at 1 day, increased binding at 3 days, a return to control levels at 7 days and decreased binding at 14 days. These data indicate that both sensitization and alterations in dopamine transporter binding occur after chronic cocaine injection but that these changes are unlikely to be directly related.

Prenatal cocaine exposure: increased striatal dopamine transporter binding in offspring at 3 and 6 months of age

Prior studies indicate that prenatal cocaine exposure can alter dopamine transporter binding in mature mice. To determine the persistence of these effects, pregnant mice were treated with cocaine, 10 mg/kg/d, during days 13 to 20 of gestation and dopamine transporter binding was evaluated in offspring at 3 and 6 months of age. In contrast to prior studies, binding in striatum was significantly increased at both time points in cocaine-exposed mice compared to controls.

Polyamine neurotoxicity is antagonized by dizocilpine in cultured chick cortical neurons

Release of endogenous polyamines may contribute to neuronal loss in ischemia and related conditions. Primary cortical neurons were exposed to spermine and spermidine and subsequently assayed for [3H]ouabain binding to quantify neuronal loss. Neuronal survival was significantly decreased in the presence of spermine at 24 h (500 microM), 48 h (250 microM and 500 microM) and 72 h (10-500 microM) relative to controls. Co-application of 250 microM spermine and 10 microM dizocilpine for 48 h completely inhibited the effect of spermine alone. Spermidine exposure (10-500 microM) did not alter neuronal survival at any of the time points. These data indicate that the polyamine spermine is toxic to neurons in vitro and that toxicity is prevented by the NMDA-associated channel antagonist dizocilpine.

[The effect of foridon on the cerebral circulation in non-narcotized animals]

In chronic experiments in rabbits, foridone, 0.3 mg/kg, i.v., caused a significant increase in overall and local cerebral circulation and pO2 in various brain regions. In conscious rats, foridone given in the same dose under 30-min carotid occlusion resulted in a less profound decrease in brain blood supply to the baseline level during recirculation and prevented disturbances in oxidative processes in brain tissue and development of brain edema.

Selective Inhibition of Ammonium Oxidation and Nitrification-Linked N 2 O Formation by Methyl Fluoride and Dimethyl Ether

Methyl fluoride (CH 3 F) and dimethyl ether (DME) inhibited nitrification in washed-cell suspensions of Nitrosomonas europaea and in a variety of oxygenated soils and sediments. Headspace additions of CH 3 F (10% [vol/vol]) and DME (25% [vol/vol]) fully inhibited NO 2 - and N 2 O production from NH 4 + in incubations of N. europaea , while lower concentrations of these gases resulted in partial inhibition. Oxidation of hydroxylamine (NH 2 OH) by N. europaea and oxidation of NO 2 - by a Nitrobacter sp. were unaffected by CH 3 F or DME. In nitrifying soils, CH 3 F and DME inhibited N 2 O production. In field experiments with surface flux chambers and intact cores, CH 3 F reduced the release of N 2 O from soils to the atmosphere by 20- to 30-fold. Inhibition by CH 3 F also resulted in decreased NO 3 - + NO 2 - levels and increased NH 4 + levels in soils. CH 3 F did not affect patterns of dissimilatory nitrate reduction to ammonia in cell suspensions of a nitrate-respiring bacterium, nor did it affect N 2 O metabolism in denitrifying soils. CH 3 F and DME will be useful in discriminating N 2 O production via nitrification and denitrification when both processes occur and in decoupling these processes by blocking NO 2 - and NO 3 - production.

Disposition of olsalazine and metabolites in breast milk

This study examined the disposition of olsalazine and its metabolites into breast milk after the ingestion of a single dose of 500 mg olsalazine. Blood and serum samples were obtained for 48 hours after the ingestion of 500 mg olsalazine in a 39-year-old lactating woman. Blood samples were obtained at .0, .5, 1, 2, 4,6, 24.5, 26, and 48 hours. Maternal milk samples were obtained at .0, .5, 2, 4, 6, 14, 24, 28, 36, and 48 hours. Olsalazine and olsalazine-S underwent high-pressure liquid chromatography analysis, and 5-ASA and Ac 5-ASA underwent fluorometric detection. Acetylated-5-ASA achieved concentrations of .8, .86, and 1.24 mumol/L in breast milk at 10, 14, and 24 hours, respectively. Olsalazine, olsalazine-S, and 5-ASA were undetectable in the breast milk for 48 hours after drug administration. Clinically significant drug exposure in the breast-fed infant is unlikely after a maternal single dose of olsalazine. Idiosyncratic hypersensitivity, however, remains a possibility even if the infant is exposed to only minute quantities.

Prenatal cocaine exposure: decreased sensitization to cocaine and decreased striatal dopamine transporter binding in offspring

Pregnant mice were treated with cocaine, 10 mg/kg/day, during days 13 to 20 of gestation. Cocaine sensitization and dopamine transporter binding were evaluated in offspring at 6 weeks of age. Sensitization, defined as the increase in activity after 5 injections of cocaine compared to 1 injection, was reduced in cocaine-exposed mice. Dopamine transporter binding in striatum was also significantly reduced in cocaine-exposed mice compared to controls.

[Experimental and clinical studies of the action of verapamil (finoptin) on the cerebral circulation in transient cerebral ischemia]

The experiments on unanesthetized rats have established that the intravenous injection of verapamil in a dose of 0.6 mg/kg during 30-minute carotid occlusion with subsequent recirculation prevents postischemic hypoperfusion, normalized oxidative processes and prevents brain tissue edema. In patients with transient cerebral circulatory disorders, a single injection of verapamil in a dose of 10 mg enhances the pulse filling of cerebral vessels. During a course therapy, the drug decreases minor and middle vessel tone, increases the REG amplitude, lowers the interhemispheric asymmetric blood filling rate, and enhances the functional resistance of cerebral vessels.

Chronic benzodiazepine administration. XI. Concurrent administration of PK11195 attenuates lorazepam discontinuation effects

Benzodiazepine discontinuation is associated with alterations in motor activity and gamma-aminobutyric acid-A receptor upregulation in a mouse model. Prior studies indicate that concurrent administration of the compound N-methyl-N-(methyl-1-propyl)chloro-2-phenyl-1-isoquinoline-3- carboxamide (PK1195), a "peripheral" site benzodiazepine antagonist, can attenuate the effects of lorazepam on tolerance and receptor alterations. To evaluate the effects of PK11195 administration on benzodiazepine discontinuation, we administered lorazepam (2 mg/kg per day), PK 11195 (1 to 10 mg/kg per day) or the combination to mice for 7 days, and then evaluated pentylenetetrazole-induced seizure threshold and benzodiazepine binding at days 1, 4, and 7 after discontinuation. Seizure threshold was reduced at 4 days after lorazepam discontinuation; this effect was attenuated by coadministration of PK11195 at 5 mg/kg per day. Lorazepam discontinuation effects were not altered by PK11195 at 1 mg/kg per day, whereas the 10-mg/kg dose was not different from 5 mg/kg per day. The competitive ligand Ro5-4864 at 10 mg/kg per day, blocked the effects of PK11195 on lorazepam discontinuation. Benzodiazepine receptor binding in vivo was increased in the cortex and hippocampus at 4 days postlorazepam discontinuation. This effect was attenuated in the hippocampus but not in the cortex by concurrent administration of PK1195. These data indicate that concurrent administration of PK11195 may attenuate discontinuation effects of lorazepam.

Reducing health care costs using claims adjudication software

An important area for reduction in health care costs is incorrect coding of physician services. Current software systems provide high-volume, consistent claims review with substantial savings for payers. The third generation of such systems offers comprehensive coverage across clinical disciplines, across individual claims, and across an entire history of claims. It is likely that these systems will be useful to both nontraditional payers, such as physician groups and hospital-based networks, and traditional payers seeking to reduce costs and enhance competitiveness.

Fluoxetine-induced SIADH: a geriatric occurrence?

After major depression was diagnosed in a 83-year-old woman, fluoxetine was prescribed. Six days later she became delirious and weak, necessitating hospitalization. She was found to have hyponatremia secondary to fluoxetine-induced syndrome of inappropriate antidiuretic hormone secretion (SIADH). Recovery was complete after discontinuation of the medication.

Benzodiazepine receptor binding of nonbenzodiazepines in vivo: alpidem, zolpidem and zopiclone

Several classes of nonbenzodiazepine compounds, including imidazopyridines such as alpidem and zolpidem and cyclopyrrolones, e.g., zopiclone, have effects similar to benzodiazepines and may act at the benzodiazepine receptor in brain. We characterized the binding of these compounds to the benzodiazepine site in three brain regions using specific uptake of the high-affinity ligand [3H]Ro15-1788 (flumazenil). For alpidem, benzodiazepine binding was decreased in cortex and hippocampus with increasing drug dose. For zolpidem, receptor binding was reduced in cortex without a dose-response effect and no effect was observed on cerebellar binding. Zopiclone did not alter binding except for a decrease in binding at the lowest dose evaluated and an increase in binding above control at the highest dose. These data corroborate prior studies indicating that the imidazopyridines appear to act at the benzodiazepine receptor, but do not support receptor subtype selectivity of zolpidem. The limited effect of zopiclone except for increased binding at high doses is also consistent with prior studies suggesting that zopiclone acts at a site distinct from the benzodiazepine receptor.