McMaster University

About: McMaster University is a education organization based out in Hamilton, Ontario, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 41361 authors who have published 101269 publications receiving 4251422 citations.

Meta-analysis of dose-fractionation radiotherapy trials for the palliation of painful bone metastases

Abstract: Purpose: To compare pain relief among various dose-fractionation schedules of localized radiotherapy (RT) in the treatment of painful bone metastases. Methods and Materials: A systematic search for randomized trials of localized RT on bone metastases using different dose fractionations was performed using Medline (1966 to February 2001) and other sources. The primary outcomes of interest were complete and overall pain relief. The studies were divided into three groups: comparisons of doses given as a single fraction, single vs. multiple fractions, and comparisons of doses given as multiple fractions. The complete and overall pain responses for studies comparing single vs. multiple fractions were pooled. Exploratory analyses of the dose-response relationship, using the biologic effective dose (α/β = 10), were performed using results from all three groups of trials. Results: Two trials comparing single vs. single, eight trials comparing single vs. multiple, and six trials comparing multiple vs. multiple fractions were included. The complete and overall response rates from studies comparing single-fraction RT (median 8 Gy, range 8–10 Gy) against multifraction RT (median 20 Gy in 5 fractions, range 20 Gy in 5 fractions to 30 Gy in 10 fractions) were homogeneous and allowed pooling of data. Of 3260 randomized patients in seven studies, 539 (33.4%) of 1613 and 523 (32.3%) of 1618 patients achieved a complete response after single and multifraction RT, respectively, giving a risk ratio of 1.03 (95% confidence interval 0.94–1.14; p = 0.5). The overall response rate was in favor of single-fraction RT (1011 [62.1%] of 1629) compared with multifraction (958 [58.7%] of 1631; risk ratio 1.05, 95% confidence interval 1.00–1.11, p = 0.04), reaching statistical significance. However, when the analysis was restricted to evaluated patients alone, the overall response rates were similar for single fraction and multifraction RT, at 1011 (72.7%) of 1391 and 958 (72.5%) of 1321, respectively (risk ratio 1.00; p = 0.9). Exploratory analyses by biologic effective dose did not reveal any dose-response relationship among the fractionation schedules used (single 8 Gy to 40 Gy in 15 fractions). Of the other results and observations reported in the trials, only the re-irradiation rates were consistently different between the treatment arms (more frequent re-irradiation in lower dose arms among trials reporting re-irradiation rates). Conclusion: Meta-analysis of reported randomized trials shows no significant difference in complete and overall pain relief between single and multifraction palliative RT for bone metastases. No dose-response relationship could be detected by including data from the multifraction vs. multifraction trials. Additional data are needed to evaluate the role of re-irradiation and the impact of RT on other treatment end points such as quality of life.

Aging, frailty and age-related diseases

Abstract: The concept of frailty as a medically distinct syndrome has evolved based on the clinical experience of geriatricians and is clinically well recognizable. Frailty is a nonspecific state of vulnerability, which reflects multisystem physiological change. These changes underlying frailty do not always achieve disease status, so some people, usually very elderly, are frail without a specific life threatening illness. Current thinking is that not only physical but also psychological, cognitive and social factors contribute to this syndrome and need to be taken into account in its definition and treatment. Together, these signs and symptoms seem to reflect a reduced functional reserve and consequent decrease in adaptation (resilience) to any sort of stressor and perhaps even in the absence of extrinsic stressors. The overall consequence is that frail elderly are at higher risk for accelerated physical and cognitive decline, disability and death. All these characteristics associated with frailty can easily be applied to the definition and characterization of the aging process per se and there is little consensus in the literature concerning the physiological/biological pathways associated with or determining frailty. It is probably true to say that a consensus view would implicate heightened chronic systemic inflammation as a major contributor to frailty. This review will focus on the relationship between aging, frailty and age-related diseases, and will highlight possible interventions to reduce the occurrence and effects of frailty in elderly people.

Stress, social support and depression in single and married mothers.

Abstract: Background: This study examined the effect of stress and social support on the relationship between single-parent status and depression. Method: A secondary data analysis of the 1994–95 National Population Health Survey was conducted. Single and married mothers who participated in the survey were derived from the general sample (N = 2,921). Logistic regression techniques were used to assess the mediating and moderating effects of stress and social support on the relationship between family structure and depression. Results: Bivariate analyses showed that, compared to married mothers, single mothers were more likely to have suffered an episode of depression (12-month prevalence), to report higher levels of chronic stress, more recent life events and a greater number of childhood adversities. Single mothers also reported lower levels of perceived social support, social involvement and frequency of contact with friends and family than married mothers. The results of the multivariate analyses showed that, together, stress and social support account for almost 40% of the relationship between single- parent status and depression. We also found a conditional effect of stress on depression by family structure. Life events were more strongly related to depression in married than in single mothers. Conclusions: A substantial part of the association between single-parent status and depression can be accounted for by differences in exposure to stress and social support.Our results suggest that it is important to examine multiple sources of stress, as exposure to both distal and proximal stressors were higher among single mothers. Limitations and directions for future research are discussed.

Ringing Ears: The Neuroscience of Tinnitus

Abstract: Tinnitus is a phantom sound (ringing of the ears) that affects quality of life for millions around the world and is associated in most cases with hearing impairment. This symposium will consider evidence that deafferentation of tonotopically organized central auditory structures leads to increased neuron spontaneous firing rates and neural synchrony in the hearing loss region. This region covers the frequency spectrum of tinnitus sounds, which are optimally suppressed following exposure to band-limited noise covering the same frequencies. Cross-modal compensations in subcortical structures may contribute to tinnitus and its modulation by jaw-clenching and eye movements. Yet many older individuals with impaired hearing do not have tinnitus, possibly because age-related changes in inhibitory circuits are better preserved. A brain network involving limbic and other nonauditory regions is active in tinnitus and may be driven when spectrotemporal information conveyed by the damaged ear does not match that predicted by central auditory processing.

Merkel cell carcinoma: changing incidence trends.

Abstract: Background The objective of this study was to define the incidence trends of Merkel cell carcinoma (MCC), a rare and aggressive cutaneous malignancy. Materials and Methods All cases of MCC of the skin between 1986 and 2001 were identified using the surveillance, epidemiology, and end results (SEER) program. Overall age-adjusted, gender-specific, age-specific, stage-specific, and regional incidence rates were calculated. All rates are per 100,000 and age-adjusted to the 2000 US standard population. Estimated annual percent change (EAPC) was calculated using a linear least squares model. Results A total of 1,124 cases of MCC were identified in the SEER registries. The rate of MCC increased from 0.15 cases per 100,000 in 1986 to 0.44 cases per 100,000 in 2001. The EAPC for the time period was 8.08%. This was statistically significant (95% CI: 6.29, 9.90, P-value < 0.05). Age-specific incidence (5-year age groups) were highest in the elderly, 4.28 per 100,000 in the 85+ age group. Conclusions MCC incidence rates have increased threefold over the 1986–2001 period. Rates are highest in the elderly population. Further etiologic studies and identification of high-risk populations are warranted. J. Surg. Oncol. 2005;89:1–4. © 2004 Wiley-Liss, Inc.