Biomedical subjects

S J Gibson

Publications and source records attributed to S J Gibson.

At least 19 recordsLinked to original sources

PubMed2004

Methodologic factors which contribute to variations in experimental pain threshold reported for older people.

Using the same study groups and psychophysical methods, we have tested the hypothesis that variations in pain threshold with advancing age are best explained by variations in stimulus duration. Fifteen young adults and 15 older people without clinical evidence of neurologic disease or psychologic dysfunction had pain thresholds determined with heat and electrical stimuli using the method of limits; for electrical stimulation a double random staircase design was used. The stimulus duration was 1-100 s for heat and 50-5000 ms for electrical stimulation. It was found that older people have an increased threshold for thermal and electrically induced pain if the stimulus duration is kept short. This result explains much of the variability in age associated pain threshold in the literature.

Adult↗

PubMed2001

The epidemiology of pain in elderly people.

Acute pain probably occurs at much the same rate across all age groups. On the other hand, self-report of chronic pain seems to increase up to, but not beyond, the seventh decade of life. Chronic pain in older people is more often experienced in major joints, the back, legs and feet, whereas visceral pain and headache are reported less often. There is a divergence between an increasing load of pain-associated disease and a plateau of chronic pain complaint in old age that probably reflects impairment in the nociceptive function of the nervous system. However, the contribution of social, behavioral, cognitive, and affective dimensions of the pain experience to this divergence between disease and pain have not been fully evaluated. Most of the answers to these and other questions require longitudinal studies with pain as the predominant focus of attention rather than addressing the symptom of pain as an ancillary measure relevant to other aspects of aging.

Age Factors↗

PubMed2001

Age-related differences in pain perception and report.

The clinical and laboratory-based evidence for age-related differences in pain perception and report are reviewed. Most clinical studies suggest a relative decrease in the frequency and intensity of pain symptoms associated with myocardial complaints, visceral infections, musculoskeletal conditions, and postoperative and malignant pain problems in adults of advanced age. The findings from experimentally controlled laboratory investigations are more equivocal and vary according to the type and intensity of noxious stimulation. Nonetheless, such studies also provide some additional support for the notion of an age-related decrease in pain perception and report. Evidence has not determined whether the observed changes are caused by the aging process or reflect other age-associated effects, including an increased presence of comorbid disease, biocultural cohort effects, or altered psychosocial influences.

Adolescent↗

PubMed2001

Development of a pain attitudes questionnaire to assess stoicism and cautiousness for possible age differences.

This study aimed to develop a pain attitudes questionnaire (PAQ) and examine its reliability and validity for use in assessing the constructs of stoicism and cautiousness relevant to pain perception. The questionnaire was administered to 373 healthy community-dwelling individuals who were subsequently divided into four age groups to test for differences in stoicism and cautiousness, two attitudes that have previously been claimed to influence pain perception and report among older adults. Factor analysis revealed that two dimensions of stoicism and two dimensions of cautiousness are measured by the scale, with reticence and superiority characterizing the first construct and self-doubt and reluctance characterizing the second. There was support for the scale's reliability and validity. Age-related increase in degree of reticence to pain, self-doubt, and reluctance to label a sensation as painful was found, emphasizing the need for careful consideration of pain attitudes in older patients who may underreport their pain symptoms.

Adolescent↗

PubMed2001

An examination of pain perception and cerebral event-related potentials following carbon dioxide laser stimulation in patients with Alzheimer's disease and age-matched control volunteers.

BACKGROUND: Pain perception is known to depend on integrated cognitive processing. Alzheimer's disease affects 5% to 10% of older adults, but the impact of this disease on pain sensitivity and report has yet to be fully investigated. AIM OF INVESTIGATION: The present study examined pain threshold, the reliability of pain report and the central nervous system processing of noxious input, as indexed by cerebral event-related potentials (CERP). METHODS: Carbon dioxide laser detection and heat pain thresholds were determined on the hand dorsum of 15 healthy older adults (Mini-Mental State Examination [MMSE] score 29.9 +/- 0.3) and 15 persons with cognitive impairment (MMSE score 12.7 +/- 6.1). Using an array of 15 silver/silver chloride scalp electrodes, the CERP and subjective rating of stimulus intensity were recorded after fixed intensity, 25 W laser stimuli. RESULTS: Compared with age-matched controls, the detection threshold for just noticeable sensation was significantly increased in elderly adults suffering from Alzheimer's disease. There was no difference in pain threshold intensity between persons with cognitive impairment and controls, although the former group was less reliable in reporting detection and pain threshold sensations. The subjective rating of a 25 W stimulus was virtually identical in both groups, and the amplitude of the major CERP component (P400) was similar; however, cognitively impaired adults exhibited a significant increase in the latency of the P400 response. CONCLUSIONS: The present findings indicate that pain perception in response to an acute heat pain stimulus is not diminished in older persons with cognitive impairment. Patients with Alzheimer's disease may be slightly less reliable in threshold pain report, although the subjective rating of evoked pain and the level of poststimulus cortical activation following noxious stimulation were found to be similar to those of controls. A longer latency of the CERP may suggest slower cortical processing of nociceptive input by persons with Alzheimer's disease.

Aged↗

PubMed2000

Adjuvant activities of immune response modifier R-848: comparison with CpG ODN.

R-848 and imiquimod belong to a class of immune response modifiers that are potent inducers of cytokines, including IFN-alpha, TNF-alpha, IL-12, and IFN-gamma. Many of these cytokines can affect the acquired immune response. This study examines the effects of R-848 on aspects of acquired immunity, including immunoglobulin secretion, in vivo cytokine production, and Ag-specific T cell cytokine production. Results are compared with those of Th1 CpG ODN. R-848 and CpG ODN are effective at skewing immunity in the presence of Alum toward a Th1 Ab response (IgG2a) and away from a Th2 Ab response (IgE). R-848 and CpG ODN are also capable of initiating an immune response in the absence of additional adjuvant by specifically enhancing IgG2a levels. Both R-848 and imiquimod showed activity when given subcutaneously or orally, indicating that the compound mechanism was not through generation of a depot effect. Although CpG ODN behaves similarly to R-848, CpG ODN has a distinct cytokine profile, is more effective than R-848 when given with Alum in the priming dose, and is active only when given by the same route as the Ag. The mechanism of R-848's adjuvant activity is linked to cytokine production, where increases in IgG2a levels are associated with IFN-alpha, TNF-alpha, IL-12, and IFN-gamma induction, and decreases in IgE levels are associated with IFN-alpha and TNF-alpha. Imiquimod also enhances IgG2a production when given with Ag. The above results suggest that the imidazoquinolines R-848 and imiquimod may be attractive compounds for use as vaccine adjuvants and in inhibiting pathological responses mediated by Th2 cytokines.

Adjuvants, Immunologic↗

PubMed2000

Age-related differences in the time course of capsaicin-induced hyperalgesia.

The effect of age on hyperalgesia, one of the most common signs of injury, has not been previously examined in humans. A psychophysical study was conducted in 10 young (26.9+/-4.6 years) and 10 older (79. 0+/-5.7 years) healthy volunteers to investigate the effect of age on the development of hyperalgesia induced by topical application of capsaicin (0.1 ml, 5 mg/ml). The capsaicin patch (diameter 2 cm) was applied for 1 h. The intensity of capsaicin-induced spontaneous sensation, mechanical pain threshold, area of flare, heat and punctate hyperalgesia were measured hourly for 3 h after the application. Older adults took a longer period to report first pain. There was no age effect on the magnitude of spontaneous sensation, flare size and area of heat hyperalgesia. The area of heat hyperalgesia rapidly decreased over time in both age groups. In marked contrast, the area of punctate hyperalgesia and associated reduction in the mechanical pain threshold were maintained in older adults over the entire 3 h test period, but resolved rapidly in young adults. We conclude that, given the same intensity of noxious stimulation, older adults display a similar magnitude of hyperalgesia as younger persons. However, once initiated, punctate hyperalgesia appears to resolve more slowly in older people. This finding may indicate age differences in the plasticity of spinal cord neurons following an acute injury.

Administration, Topical↗

PubMed2000

A community-based program that provides free choice of intervention for older people with chronic pain.

This study sought to evaluate the efficacy of a community-based intervention program that provides free choice of intervention for improving outcomes for community-dwelling older people with chronic nonmalignant pain. A quasiexperimental before and after nonequivalent group design was used. The treated group was composed of 71 participants, and the untreated group was composed of 40 individuals. A 6-month follow-up measurement was included to determine the long-term effects of the program. The findings of the program showed significant benefits for those who completed the program compared with those who did not participate. Evaluation of the program suggested that an initial educational seminar had a positive impact that empowered the participants to make more informed choices regarding interventions for managing pain. Significant reduction in pain intensity and improved level of physical activity were reported by the participants at completion of the interventions. However, results of a 6-month follow-up showed that only the benefits for physical activity were maintained. The findings show that the present program improved the short-term outcomes for older people with chronic pain and has potential as a clinical option for accessible and low-cost pain management for older people with chronic pain.

Journal Article↗

PubMed2000

Increased movement pain in osteoarthritis of the hands is associated with A beta-mediated cutaneous mechanical sensitivity.

The relationship between joint pain and hyperalgesia has been explored in animal models of articular inflammation, but is yet to be shown in the most common rheumatologic condition: osteoarthritis. In this study, cutaneous thermal and mechanical pain thresholds were measured over the thumb of patients with osteoarthritis of the hands. In symptomatic patients, pain was manipulated through resisted active movement of the thumb. Provocation of movement pain (MP) was associated with a sustained fall in mechanical pain thresholds. Thermal pain thresholds remained stable during increases in joint pain. Increased mechanical sensitivity after exacerbation of MP was alleviated by A beta fiber blockade. It appears that superficial tenderness over the osteoarthritic thumb fluctuates with pain arising from movement of the joint. It is concluded that dorsal horn mechanisms contribute to MP-related hyperalgesia in osteoarthritis of the hands.

Journal Article↗

PubMed1999

Dendritic cell maturation and subsequent enhanced T-cell stimulation induced with the novel synthetic immune response modifier R-848.

Agents that enhance dendritic cell maturation can enhance T-cell activation and therefore may improve the efficiency of vaccines or improve cellular immunotherapy. Previously, we demonstrated that a novel low-molecular-weight synthetic immune response modifier, R-848, induces IL-12 and IFN-alpha secretion from monocytes and macrophages. Here we report that R-848 induces the maturation of human monocyte-derived dendritic cells. Characteristic of dendritic cell maturation, R-848 treatment induces cell surface expression of CD83 and increases cell surface expression of CD80, CD86, CD40, and HLA-DR. Additionally, R-848 induces cytokine (IL-6, IL-12, TNF-alpha, IFN-alpha) and chemokine (IL-8, MIP-1alpha, MCP-1) secretion from dendritic cells. Most significantly, R-848 enhances dendritic cell antigen presenting function, as measured by increased T-cell proliferation and T-cell cytokine secretion in both allogeneic and autologous T-cell systems. Consequently, low-molecular-weight synthetic molecules such as R-848 and its derivatives may be useful as vaccine adjuvants or as ex vivo stimulators of dendritic cells for cellular immunotherapy.

Antigens, CD↗

PubMed1999

Modulation of TH1 and TH2 cytokine production with the immune response modifiers, R-848 and imiquimod.

Cytokines produced by antigen-presenting cells are known to affect the development and cytokine profile of T cells. The immune response modifiers imiquimod and R-848 were previously shown to stimulate human and mouse cultures to secrete interferon-alpha. Results from the present study demonstrate that R-848 and imiquimod are capable of inducing interleukin-12 and interferon-gamma in mouse and human cell cultures. Both CD4(+) and CD8(+) T lymphocytes were responsible for producing IFN-gamma following stimulation with R-848. Macrophages were required for induction of interferon-gamma by R-848 and the cytokines IFN-alpha and IL-12 mediated this response. R-848 and imiquimod were also found to inhibit IL-4 and IL-5 production in mouse and human culture systems. The inhibition of IL-5 in response to R-848 is seen in cultures containing CD4(+) lymphocytes and macrophages and is mediated in part by IFN-alpha. These data suggest that imiquimod and R-848 may have clinical utility in diseases where cell-mediated immune responses are important and in diseases associated with overexpression of IL-4 or IL-5 such as atopic disease.

Adjuvants, Immunologic↗

PubMed1999

Factors associated with analgesic and psychotropic medications use by community-dwelling older people with chronic pain.

OBJECTIVE: The present study sought to examine use prevalence and factors associated with use of analgesic and psychotropic medications in community-dwelling older people with chronic non-malignant pain. METHOD: The study group comprised 193 community-dwelling older people with daily chronic non-malignant pain who were selected from a random sample of 1,000 older people in Melbourne. RESULTS: The use prevalence for the study group was 63% for analgesics and 39% for psychotropic medications, which is higher than the general older population without chronic pain (p < 0.00001). More women with chronic pain used analgesics, while psycho-social factors such as problems with sleeping and living at home alone were found to be associated with an increased use of psychotropic medications. CONCLUSION: A high proportion of community-dwelling older people with chronic non-malignant pain use analgesic and psychotropic medications. IMPLICATIONS: These findings provide the basis for further investigation into the level and appropriateness of analgesic and psychotropic medication use by older people with chronic pain.

Aged↗

PubMed1998

The psychosocial health status of carers of persons with dementia: a comparison with the chronically ill.

This project aimed to determine overall psychosocial health (measured using the psychosocial dimension of the Functional Limitations Profile) and factors which influence this in a group of carers of those with dementia and to compare their psychosocial health with that of older people attending general practitioners (GPs); arthritis support groups and a pain clinic (out-patients) and a group of community dwellers undergoing renal dialysis. The carer group showed a significant decrease in recreation and pastimes and social interactions compared to older GP attenders. The carers showed similar restrictions in social interactions and recreation to those with chronic arthritis, but the latter were more impaired in the domains of emotional behaviour and sleep and rest. The older people attending a pain clinic did not differ in the areas of alertness and social interactions compared to the carer group. The dialysis group demonstrated the greatest dysfunction overall. These results suggest that the psychosocial health of carers of those with dementia is impaired, the profile of which differs from those suffering with chronic diseases. Social and recreation activities appear most affected in the carers. Commensurate with studies exploring the health status of those suffering from diseases, the measurement of the psychosocial health status of carers should also be considered in the scope of assessment and intervention.

Analysis of Variance↗

PubMed1998

Cytokine induction in hairless mouse and rat skin after topical application of the immune response modifiers imiquimod and S-28463.

ALDARA (imiquimod cream 5%) recently became available for the treatment of genital and perianal warts; however, the topical mechanism of action of imiquimod is not fully understood. Imiquimod, and its analogs R-842, S-27609, and S-28463, are potent anti-viral and anti-tumor agents in animal models. Much of the biologic activity of these compounds can be attributed to the induction of cytokines, including interferon-alpha, tumor necrosis factor-alpha, interleukins-1, -6, -8, and others. This study was performed to characterize the response of mice and rats to topical application of imiquimod and S-28463 and also to evaluate these agents in cultures of murine and human skin cells. Topical administration of imiquimod or S-28463 to the flanks of hairless mice and rats leads to increases in local concentrations of interferon and tumor necrosis factor in the skin. The concentrations of interferon and tumor necrosis factor were higher at the site of drug application than in skin from the contralateral flank or skin from untreated animals. Interferon-alpha mRNA levels were also elevated in the skin of mice after topical application of either imiquimod or S-28463. In vitro, both imiquimod and S-28463 induced increases in interferon and tumor necrosis factor in cultures of cells isolated from hairless mouse skin. Imiquimod also increased interleukin-8 concentrations in human keratinocyte and fibroblast cultures, whereas S-28463 induced increases in tumor necrosis factor in fibroblast cultures. These results demonstrate that imiquimod and S-28463 stimulate production of cytokines in the skin after topical application, which may play a major role in its activity in genital wart patients.

Adjuvants, Immunologic↗

PubMed1997

Induction of cytokines in cynomolgus monkeys by the immune response modifiers, imiquimod, S-27609 and S-28463.

Imiquimod, S-27609 and S-28463 are imidazoquinolines known to have antiviral and antitumour properties mediated by the induction of cytokines, in particular interferon alpha (IFN-alpha). This study evaluated these compounds for their ability to induce cytokines and cytokine specific messenger RNAs (mRNA) in cynomologus monkeys (Macaca fascicularis). Peripheral blood mononuclear cell (PBMC) cultures from monkeys produced IFN, interleukin 1beta (IL-1beta), IL-6 and IL-8 after treatment with imiquimod, S-27609 and S-28463. Tumour necrosis factor alpha (TNF-alpha) was also increased in cultures stimulated with S-27609 or S-28463. Monkey PBMCs stimulated with imiquimod, S-27609 and S-28463 showed increased mRNA levels of IFN-alpha, IL-1alpha, IL-6 and the IFN inducible protein, MxA above those seen in untreated cultures. S-27609 and S-28463 also had higher TNF-alpha mRNA expression than cultures not receiving drugs. When compared to lipopolysaccharide (LPS), S-27609 was less effective at inducing IL-1beta, IL-6, IL-8 and TNF-alpha but induced higher concentrations of IFN. Similar results were seen when evaluating cytokine mRNA levels. Upon oral administration to monkeys, S-28463 stimulated a dose-dependent increase in serum concentrations of IFN, TNF-alpha, IL-1 receptor antagonist (IL-1Ra) and IL-6, while imiquimod induced increases in IFN and IL-1Ra concentrations. Finally, skin biopsies from monkeys treated topically with S-28463 had increases over baseline in mRNA for IFN-alpha, IL-1alpha, IL-6 and MxA protein. The data show that imidazoquinolines induce cytokines and cytokine specific mRNA in cynomolgus monkeys. These results demonstrate the usefulness of human amplimers and human ELISAs in the detection of cytokine specific mRNAs and proteins in cynomolgus monkeys.

Adjuvants, Immunologic↗

PubMed1997

The measurement of mood states in older adults.

This study examined the reliability and validity of the Profile of Mood States (POMS) questionnaire when administered to 479 community-dwelling older adults. Factor analysis replicated the original factor structure identified in young-adult samples, suggesting that older adults adopt the same underlying constructs of mood when responding to the POMS. There was strong support for concurrent validity, and this instrument was able to discriminate between healthy adults and patients with known mood disturbance. Excellent internal consistency of POMS subscales and very good retest reliability were noted. A significant age-related decline in self-reported mood states emphasizes the need for age-specific norms, although response bias rather than age itself was shown to account for this decline. Overall, the POMS can be recommended as a reliable and valid measure of mood states in older adults, although it is clear that normative values for this test vary considerably over the age spectrum.

Affect↗

PubMed1997

The classification of patients with chronic pain: age as a contributing factor.

OBJECTIVE: To explore the influence of age on the empirical classification of patients with chronic pain. DESIGN: Cluster analyses of two cohorts defined by age. SETTING: Two outpatient pain management clinics for young and older people. SAMPLE: The sample consisted of 340 patients between the ages of 17 and 93 years, who were consecutively assessed on admission to the multidisciplinary pain clinics. The subjects were allocated to two groups according to age; either 17 to 65 years or 66 years and older. MEASUREMENTS: Clustering was carried out using standardised scores from measures of pain (McGill Pain Questionnaire), depression (Zung or Geriatric Depression Scales), and impact of pain (Sickness Impact Profile adapted for pain). RESULTS: Previous classifications of younger adults were replicated in the clusters of: "Good Pain Control," "Positive Adaption to Pain," and "Chronic Pain Syndrome." A fourth cluster, "High Impact," was identified in the older group and subsequently replicated in the combined sample. This group consisted of subjects with high levels of impact of pain and depression and low levels of pain. CONCLUSION: Age differences are present in the clinical presentation of chronic pain patients. Some older patients with chronic pain present with a unique constellation of clinical symptoms, and the classic patient profile of high pain, high impact, and high mood disturbance (i.e., Chronic Pain Syndrome) identified in younger to middle-aged adults does not occur as frequently in older patients. A number of explanations are presented to account for these differences, including comorbidity as well as other medical, psychological, and social factors.

Adolescent↗

PubMed1997

Labor positions on worksite tobacco control policies: a review of arbitration cases.

Although worksite smoking restrictions have become increasingly common in recent years, organized labor has generally not been involved in the adoption of these policies; some evidence suggests that unions often oppose the adoption of worksite smoking policies. To contribute to an understanding of labor's role in tobacco control policies, this paper reports the results of a review of 85 arbitration cases and 5 cases of unfair labor practices charges published between 1986 and 1994. In most of the cases reviewed, management unilaterally imposed a new smoking policy, which the union then grieved. Union opposition to the policy generally focused on the process by which the policy was adopted, rather than the content of the policy; the concern was that management had breached its duty to bargain with the union regarding the adoption of the policy. These results underline the importance of joint labor-management actions on worksite tobacco control policies.

Employee Grievances↗