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.

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.