Pain
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There has been a surge in interest in medicinal cannabis in Canada. We conducted a questionnaire survey to determine the current prevalence of medicinal cannabis use among patients with chronic non-cancer pain, to estimate the dose size and frequency of cannabis use, and to describe the main symptoms for which relief was being sought. Over a 6-week period in mid-2001, 209 chronic non-cancer pain patients were recruited in an anonymous cross-sectional survey. ⋯ We conclude that cannabis use is prevalent among the chronic non-cancer pain population, for a wide range of symptoms, with considerable variability in the amounts used. Discussions between patients and health care providers concerning cannabis use may facilitate education and follow up, and would allow side effects and potential interactions with other medications to be monitored. Clinical trials of cannabis for chronic non-cancer pain are warranted.
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Comparative Study
Visceral and cutaneous hypersensitivity in Persian Gulf war veterans with chronic gastrointestinal symptoms.
Approximately 697000 United States military personnel participated in the Persian Gulf War (PGW) between August 1990 and March 1991. By April 1997, over 25% of veterans reported chronic health complaints of underdetermined etiology. Gastrointestinal symptoms were among the most frequently reported symptoms including abdominal pain and diarrhea. ⋯ Results of the hierarchical regressions indicated that the psychological measures (i.e. anxiety, somatic focus) accounted for a significant amount of variance in each of the pain measures. PGW veterans who developed chronic abdominal pain and diarrhea during their tour of duty exhibit visceral hypersensitivity similar to patients with the irritable bowel syndrome. These veterans also have cutaneous hypersensitivity and higher levels of anxiety and somatic focus accounting for these differences in pain reporting.
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Case Reports
Musculoskeletal pain in the Netherlands: prevalences, consequences and risk groups, the DMC(3)-study.
The objective of this paper was to present estimates on the prevalence of musculoskeletal pain of five different anatomical areas and ten anatomical sites, and their consequences and risk groups in the general Dutch population. Cross-sectional data from a population-based study of a sex-age stratified sample of Dutch inhabitants of 25 years and older were used. With a postal questionnaire data was assessed on musculoskeletal pain, additional pain characteristics (location, duration, course), its consequences (utilization of health care, sick leave and limitation in daily life) and general socio-demographic characteristics. ⋯ Between 33 and 42% of those with complaints consulted their general practitioner about their pain. With the exception of persons who are work disabled, general sociodemographic characteristics cannot be used to identify high risk groups. Musculoskeletal pain is common in all subgroups of the population and has far-reaching consequences for health, work and the use of health care.
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Comparative Study
Transgene-mediated enkephalin release enhances the effect of morphine and evades tolerance to produce a sustained antiallodynic effect in neuropathic pain.
We examined the pharmacologic characteristics of herpes simplex virus (HSV) vector-mediated expression of proenkephalin in the dorsal root ganglion in a rodent model of neuropathic pain. We found that: (i). vector-mediated enkephalin produced an antiallodynic effect that was reversed by naloxone; (ii). vector-mediated enkephalin production in animals with spinal nerve ligation prevented the induction of c-fos expression in second order sensory neurons in the dorsal horn of spinal cord; (iii). the effect of vector-mediated enkephalin enhanced the effect of morphine, reducing the ED(50) of morphine 10-fold; (iv). animals did not develop tolerance to the continued production of vector-mediated enkephalin over a period of several weeks; and, (v). vector transduction continued to provide an analgesic effect despite the induction of tolerance to morphine. This is the first demonstration of gene transfer to provide an analgesic effect in neuropathic pain. The pharmacologic analysis demonstrates that transgene-mediated expression and local release of opioid peptides produce some effects that are distinct from peptide analogues delivered pharmacologically.
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Comparative Study
Affective associative learning modifies the sensory perception of nociceptive stimuli without participant's awareness.
The present experiment examined the possibility to change the sensory and/or the affective perception of thermal stimuli by an emotional associative learning procedure known to operate without participants' awareness (evaluative conditioning). In a mixed design, an aversive conditioning procedure was compared between subjects to an appetitive conditioning procedure. Both groups were also compared within-subject to a control condition (neutral conditioning). ⋯ This experiment shows that it is possible to modify the perception of intensity of thermal stimuli by a non-conscious learning procedure based on the transfer of the valence of the unconditioned stimuli (pleasant or unpleasant slides) towards the conditioned stimuli (non-painful and painful thermal stimuli). These results plead for a conception of pain as a conscious output of complex informational processes all of which are not accessible to participants' awareness. Mechanisms by which affective input may influence sensory experience and clinical implications of the present study are discussed.