Altered Methionine Metabolism in Cancer Cells.

Many different types of cancer cells have been shown to be methionine (MET) dependent. Cancer cells, unlike normal cells, grow poorly or not at all when MET is restricted. Cancer cells have an elevated requirement for exogenous MET for growth, despite high levels of endogenous synthesis.

Methylnaltrexone: its pharmacological effects alone and effects on morphine in healthy volunteers.

Rationale: Methylnaltrexone bromide (MTNX) is a peripherally acting mu-opioid receptor antagonist, prescribed for the treatment of opioid-induced constipation in patients with advanced illness who are receiving palliative care. Studies have used this drug to determine if other opioid-induced effects besides constipation are altered by MTNX in humans and have suggested, based on their results, that these other effects are altered by peripheral opioid actions.

Objective: The primary objective of this report is to present results that provide indirect evidence that MTNX has centrally mediated effects, albeit slight, and secondarily to describe the effects of MTNX on psychopharmacological effects of morphine.

Separate and combined psychopharmacological effects of alprazolam and oxycodone in healthy volunteers.

Background: There are epidemiological data indicating that medical and/or nonmedical use of prescription opioids oftentimes involves concurrent use of other substances. One of those substances is benzodiazepines. It would be of relevance to characterize the effects of an opioid and a benzodiazepine when taken together to determine if measures related to abuse liability-related effects and psychomotor performance impairment are increased compared to when the drugs are taken alone.

Subjective, psychomotor, and physiological effects of pregabalin alone and in combination with oxycodone in healthy volunteers.

Pregabalin is an anticonvulsant drug indicated for neuropathic disorders and fibromyalgia. Some chronic pain patients suffering from these disorders take both this drug and an opioid for pain relief. Pregabalin is a scheduled drug under the Controlled Substances Act.

Characterizing the subjective and psychomotor effects of carisoprodol in healthy volunteers.

Carisoprodol is a centrally acting drug used to relieve skeletal muscle spasms and associated pain in acute musculoskeletal conditions. There is evidence from different sources that this oral muscle relaxant is abused and that it is associated with impairment leading to arrests for "driving under the influence" as well as increased risk of automobile accidents. Its subjective and psychomotor effects in healthy volunteers at therapeutic and supratherapeutic doses have not been well-characterized, and form the basis of this report.

Subjective and psychomotor effects of carisoprodol in combination with oxycodone in healthy volunteers.

Background: Some chronic pain patients on long-term opioid therapy also take centrally active skeletal muscle relaxants. One of those muscle relaxants is carisoprodol, a drug that is abused and capable of producing impairment. It would be of relevance to characterize the effects of an opioid and carisoprodol when taken together to determine if abuse liability-related measures and psychomotor impairment are increased compared to when the drugs are taken alone.

Analysis of WAIS-IV index score scatter using significant deviation from the mean index score.

The Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) does not include verbal IQ and performance IQ scores, as provided in previous editions of the scale; rather, this edition provides comparisons among four index scores, allowing analysis of an individual's WAIS-IV performance in more discrete domains of cognitive ability. To supplement the pairwise index score comparisons included in the WAIS-IV manuals, this article describes the use of the mean of the four index scores (the average index score) as a baseline for analyzing index score variability and as a method for identifying strengths and weaknesses within an individual's index score pattern. Davis's formula was used to calculate critical values for the identification of index scores with a statistically significant difference from the average index score.

Effects of naloxone on nitrous oxide actions in healthy volunteers.

A number of studies have examined the effects of naloxone on nitrous oxide-induced analgesia with conflicting results. In the present study the effects of a relatively high dose of naloxone was examined to determine its effects on nitrous oxide-induced analgesia, as well as on the subjective and psychomotor effects of nitrous oxide. Fourteen subjects participated in a four-session crossover trial in which they received intravenous injections of either saline or 30mg/70kg naloxone 10min into a 35min period in which they were inhaling either 100% oxygen or 30% nitrous oxide in oxygen.

The effects of subanesthetic concentrations of sevoflurane and nitrous oxide, alone and in combination, on analgesia, mood, and psychomotor performance in healthy volunteers.

Unlabelled: We studied the effects of subanesthetic concentrations of sevoflurane and nitrous oxide, alone and in combination, on analgesia, mood, and psychomotor performance in human volunteers. We hypothesized that nitrous oxide and sevoflurane would produce both opposing and potentiating effects within the same study. Over the course of three sessions, 20 subjects inhaled 0%, 0.

Subjective, psychomotor, cognitive, and analgesic effects of subanesthetic concentrations of sevoflurane and nitrous oxide.

Background: Sevoflurane is a volatile general anesthetic that differs in chemical nature from the gaseous anesthetic nitrous oxide. In a controlled laboratory setting, the authors characterized the subjective, psychomotor, and analgesic effects of sevoflurane and nitrous oxide at two equal minimum alveolar subanesthetic concentrations.

Methods: A crossover design was used to test the effects of two end-tidal concentrations of sevoflurane (0.

Effects of information on the reinforcing, subjective, and psychomotor effects of nitrous oxide in healthy volunteers.

The purpose of this study was to characterize the reinforcing, subjective, and psychomotor effects of nitrous oxide (N2O) in healthy volunteers who were given different amounts of information regarding the drugs they were being administered in the experiment. A choice procedure was used in which subjects first sampled a placebo and a given concentration of N2O and then chose between the two. N2O concentration varied across the four-session experiment from 10-40%.

Analgesic and psychomotor effects of thiopental at subanesthetic concentrations in human volunteers.

Background: Studies of the effects of barbiturates on the modulation of pain have produced mixed results. In a prospective, double-blind, randomized, placebo-controlled trial, we studied the effects of thiopental at presumed steady-state, "conscious sedation" levels on cold-pressor-induced pain in 12 healthy volunteers.

Methods: Five drug conditions were used, each condition consisting of an injection (either drug or placebo) with a 20-min infusion and a 160-min recovery period.

The effects of alcohol history on the reinforcing, subjective and psychomotor effects of nitrous oxide in healthy volunteers.

The purpose of this study was to characterize the reinforcing, subjective and psychomotor effects of nitrous oxide in healthy volunteers with different alcohol histories. Subjects were divided into two groups: light drinkers (n = 9) and moderate drinkers (n = 10). A choice procedure was used in which subjects first sampled placebo and a given concentration of nitrous oxide, and then chose between the two.

The reinforcing effects of brief exposures to nitrous oxide in healthy volunteers.

The reinforcing and subjective effects of brief (about 1.5 min) exposures to nitrous oxide, ranging from inspired concentrations of 20-80% in oxygen, were examined in 11 healthy volunteers. A choice procedure was used in which during each of four sessions, subjects first sampled a given concentration of nitrous oxide and placebo oxygen, and then chose between the two.

Midazolam does not influence intravenous fentanyl-induced analgesia in healthy volunteers.

The effects of saline and intravenous midazolam (0.5, 1, and 2 mg per 70 kg) in combination with intravenous fentanyl (0.1 mg/70 kg) were examined on pain induced by a cold pressor test.

Awakening, clinical recovery, and psychomotor effects after desflurane and propofol anesthesia.

We compared postanesthetic and residual recovery of desflurane versus propofol anesthesia. Twenty volunteers were anesthetized for 1 h at 1-wk intervals with either propofol (induction) plus desflurane (1.25 minimum alveolar anesthetic concentration) in O2 (PD), propofol plus desflurane in N2O-O2 (PDN), propofol plus propofol infusion with N2O-O2 (PPN), or desflurane (induction) plus desflurane in O2 (DD).

Propofol at conscious sedation doses produces mild analgesia to cold pressor-induced pain in healthy volunteers.

Study Objective: To determine whether subanesthetic doses of propofol have analgesic effects in healthy volunteers.

Design: Prospective, double-blind, placebo-controlled, randomized, crossover trial.

Setting: Human psychomotor performance laboratory within our anesthesia and critical care department.

Lack of acute tolerance development to the subjective, cognitive, and psychomotor effects of nitrous oxide in healthy volunteers.

A crossover, double-blind trial was conducted using eleven healthy volunteers to determine whether and the degree to which acute drug tolerance occurred to the subjective, cognitive, and psychomotor effects of a range of subanesthetic nitrous oxide doses (0, 10, 20, 30, and 40%). There was little evidence of acute drug tolerance to the subjective measures or to the cognitive/psychomotor impairing effects of nitrous oxide at any of the concentrations tested over the course of the 120-min inhalation.

Differential acute tolerance development to effects of nitrous oxide in humans.

The analgesic, subjective, and psychomotor effects of 0, 10, 20, 30, and 40% nitrous oxide in oxygen were studied in 10 volunteers to determine if acute tolerance developed differentially to these variables. In this prospective, randomized, crossover, double-blind study, volunteers inhaled either placebo (100% oxygen) or one of the aforementioned doses of nitrous oxide for 120 min. During this period, volunteers immersed their non-dominant forearm, for 3 min, in ice-cold water at 25, 70 and 115 min from the onset of the inhalation.

Examining the subjective, psychomotor and reinforcing effects of nitrous oxide in healthy volunteers: a dose-response analysis.

The present study examined the subjective, psychomotor and reinforcing effects of 10%, 20%, 30% and 40% nitrous oxide in oxygen in 16 healthy volunteers using a choice procedure in which sampling (e.g. 20% nitrous oxide and oxygen-placebo) and choice trials (e.

The acute and residual effects of subanesthetic concentrations of isoflurane/nitrous oxide combinations on cognitive and psychomotor performance in healthy volunteers.

A blind, randomized, cross-over trial was conducted to determine the degree of psychomotor/cognitive impairment and the recovery profile produced by combinations of subanesthetic concentrations of isoflurane and nitrous oxide in healthy volunteers. In the experiment, subjects (n = 10) inhaled 100% oxygen-placebo, 30% nitrous oxide in oxygen, and 0.2% and 0.

Flumazenil may attenuate some subjective effects of nitrous oxide in humans: a preliminary report.

Two double-blind, randomized, crossover trials were conducted to study whether the benzodiazepine antagonist, flumazenil, would interact with the subjective and psychomotor effects of nitrous oxide in healthy volunteers. In both experiments, eight subjects inhaled 30% nitrous oxide in oxygen for 35 min and were challenged, 10 min into the inhalation, with flumazenil. Experiment 1 tested a range of flumazenil doses used clinically (0, 0.

A dose-response study of the effects of intravenous midazolam on cold pressor-induced pain.

The effects of intravenous midazolam (0.75, 1.5, and 3 mg/70 kg) were examined and compared to that of fentanyl (0.

Effects of naloxone on the subjective and psychomotor effects of nitrous oxide in humans.

The effects of naloxone on the mood-altering and psychomotor-impairing effects of nitrous oxide were examined in two studies. Each of the double-blind, randomized trials tested effects of three doses of naloxone or saline placebo during inhalation of 30% nitrous oxide in oxygen or 100% oxygen placebo. Experiment 1 tested a range of naloxone doses used clinically to reverse opiate-induced respiratory depression (0, 0.