Pain
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Randomised controlled trials (RCTs) alone are unlikely to provide reliable estimates of the incidence of rare events because of their limited size. Cohort, case control, and other observational studies have large numbers but are vulnerable to various kinds of bias. Wanting to estimate the risk of death from bleeding or perforated gastroduodenal ulcers with chronic usage of non-steroidal anti-inflammatory drugs (NSAIDs) with greater precision, we developed a model to quantify the frequency of rare adverse events which follow a biological progression. ⋯ From these numbers we calculated the number-needed-to-treat for one patient to die due to gastroduodenal complications with chronic (>/=2 months) NSAIDs as 1/((0.69x¿6-16%, average 12%¿)-0.002%))=909-2500 (average 1220). On average 1 in 1200 patients taking NSAIDs for at least 2 months will die from gastroduodenal complications who would not have died had they not taken NSAIDs. This extrapolates to about 2000 deaths each year in the UK.
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Much of our current understanding about chronic pain and the mechanisms of nociception has been derived from animal models (Bennett GJ. Animal models of neuropathic pain. In: Gebhart, GF, Hammond DL, Jensen TS, editors. ⋯ One such model that is frequently used in animals to study pain associated with inflammation is the subcutaneous injection of complete Freund's adjuvant (CFA). For ethical reasons, however, little information is available from humans concerning pain associated with this form of inflammation. Due to an inadvertent subcutaneous injection of CFA into the terminal phalanx of this investigator, a study with an N of 1, was conducted to compare the subjective effects of CFA-induced inflammation with objective measurements.
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This study presents the sociodemographic distribution of tooth pain and the dental care utilization of affected individuals. Data for adults 20 years of age and over were derived from the 1989 National Health Interview Survey's supplements on dental health, orofacial pain, and health insurance (n=33073). Prevalence of tooth pain by socioeconomic status (SES) and adjusted odds ratios of reporting tooth pain in the past 6 months and of having no dental visits in the past year among persons reporting pain in the previous 6 months were computed taking into account the survey's complex sample design. ⋯ In the younger age group, tooth pain was more likely to be reported by those with low SES than it was by those with high SES; in the older age group, tooth pain was more likely reported by non-Hispanic blacks than it was by non-Hispanic whites or Hispanics. Of those reporting pain, younger and older non-Hispanic blacks and persons with lower educational attainment were more likely not to have a dental visit in the previous 12 months. Persons with low SES characteristics were more likely to report tooth pain and to endure their pain without the benefit of dental care while the pain was present.
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The study of neonatal gender differences in pain expression is important since neonatal pain behavior occurs prior to any learned reaction pattern. The objective of this study was to verify the presence of gender differences in pain expression in preterm and term newborn infants. Sixty-five consecutive neonates (37 female and 28 male infants) with gestational age between 28 and 42 weeks and with 25-120 h of life were studied. ⋯ No significant interactions between gestational age and time, nor between gestational age and gender were noted, for both NFCS and NIPS. In conclusion, recently born female neonates of all gestational ages expressed more facial features of pain than male infants, during the capillary puncture and 1 min afterwards. Maybe differences in pain processing and/or pain expression among genders may explain this finding.
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A total of 68 neurons were recorded from the ventro-postero-lateral nucleus of thalamus (VPL) in rats with a unilateral chronic constriction injury (CCI) of the sciatic nerve (n=20), sham operation (n=24) and naive rats (n=24), and effects of the lesion of dorsal column (DC) pathway [DC lesion or DC+gracile nucleus lesions] on VPL nucleus neuronal activities were studied. In the VPL nucleus contralateral to the CCI (receiving input from the injured nerve), response latencies of low threshold mechanoreceptive (LTM) and wide dynamic range (WDR) neurons to electrical stimulation of the sciatic nerve were significantly longer than that in the contralateral VPL nucleus receiving input from the sham-operated side (P<0.05). In contrast, response latencies of LTM and WDR neurons to DC stimulation were not different between the sham operated and CCI sides (0.05). ⋯ The decrease in noxious stimulus-evoked responses of WDR neurons in the VPL nucleus contralateral to the CCI side after DC and DC+gracile nucleus lesions was greater than that in the VPL nucleus contralateral to the sham operated side and naive animals. These results indicated that DC and DC+gracile nucleus lesions produced selective and stronger effect on noxious responses of VPL nucleus WDR neurons receiving input from the site of nerve injury. The findings suggest that the gracile nucleus-thalamic pathway conveys, or modulates, nociceptive information to the VPL nucleus following peripheral nerve injury, resulting in an increase in VPL nucleus response to noxious stimuli that contributes to the development of mechanical hyperalgesia.