Annals of medicine
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This paper describes the responses of peripheral and central visceral nociceptive systems to acute injury and discusses these observations in relation to the concept of 'pre-emptive analgesia'. Visceral nociceptors are known to respond to injury but are also known to become sensitized to non-noxious stimuli during the inflammatory process that follows intense noxious stimulation. ⋯ Therefore it is proposed that the concept of 'pre-emptive analgesia', as such, has no neurophysiological basis. Any analgesic procedure aimed at reducing postoperative pain must not only prevent the arrival in the CNS of the initial afferent barrage evoked in nociceptive endings but also reduce or eliminate the persistent discharges of sensitized nociceptors during the inflammatory repair process that are critically important for the maintenance of the central pain state.
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Many studies in several species, including humans, have identified a subset of primary afferent nerve fibres that are activated by potential or actual tissue-damaging stimuli. Discharge patterns of these nociceptive afferents faithfully reproduce some aspects of the applied stimuli (e.g. shape of the stimulus-response function) but not others (e.g. time-course of a sustained stimulus). ⋯ Therefore, the painfulness of a stimulus cannot be deduced from nociceptor discharges alone; central processing needs to be taken into account, particularly central summation. In addition to the immediate responses of nociceptive afferents to external stimulation, acute pain mechanisms also comprise the short-term plasticity of the nociceptive system as a consequence of prolonged noxious stimulation.
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Vulvodynia is a complex multifactorial and multidisciplinary clinical syndrome of unexplained vulvar pain, sexual dysfunction, and psychological disability. Because of the absence of abnormal physical findings among such patients, vulvodynia was long thought to be solely a psychosomatic syndrome. The incidence or prevalence of vulvodynia has not been well studied. ⋯ The most common subtypes are vulvar vestibulitis syndrome, cyclic vulvovaginitis and dysesthetic vulvodynia. Simple practice guidelines can be developed to facilitate the evaluation and management of such patients. Systematic epidemiological, etiological and therapeutic studies of vulvodynia are urgently needed.
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The adipsin-ASP pathway provides a mechanism by which the adipocyte is able to regulate its rate of de novo triglyceride synthesis and reesterification. The adipocyte can synthesize and secrete the three proteins necessary for the formation of the effector molecule, acylation stimulating protein (ASP). ASP increases membrane transport of glucose and the activity of diacylglycerol acyltransferase and by virtue of both of these effects markedly increases the rate of triglyceride synthesis. ⋯ Accordingly, the concept of microenvironmental metabolic regulation of triglyceride hydrolysis at the endothelial surface and triglyceride synthesis within the adipocyte will be presented. In addition, the pathogenetic sequence by which dysfunction of this pathway can lead to dyslipoproteinaemia will be reviewed. Emphasis, however, will be placed on the role this pathway may play in the pathogenesis of obesity and the adaptation to negative caloric balance in the obese.