Mucosal vaccination with formalin-inactivated avian metapneumovirus subtype C does not protect turkeys following intranasal challenge.

Studies were performed to determine if mucosal vaccination with inactivated avian metapneumovirus (aMPV) subtype C protected turkey poults from clinical disease and virus replication following mucosal challenge. Decreases in clinical disease were not observed in vaccinated groups, and the vaccine failed to inhibit virus replication in the tracheas of 96% of vaccinated birds. Histopathologically, enhancement of pulmonary lesions following virus challenge was associated with birds receiving the inactivated aMPV vaccine compared to unvaccinated birds. As determined by an enzyme-linked immunosorbent assay (ELISA), all virus-challenged groups increased serum immunoglobulin (Ig) G and IgA antibody production against the virus following challenge; however, the unvaccinated aMPV-challenged group displayed the highest increases in virus-neutralizing antibody. On the basis of these results it is concluded that intranasal vaccination with inactivated aMPV does not induce protective immunity, reduce virus shedding, or result in decreased histopathologic lesions.

General mortality from 1944 through 1994 for a silicon-based chemical company.

The objective of this study is to reevaluate the statistically significant elevated risk of lung cancer among men with >or=20 years of employment at Dow Corning Corporation, a manufacturer of silicon-based materials. The cohort included 712 deaths among 8266 employees who were hired from 1943 to 1992 with follow-up through 1994. Standardized mortality ratios (SMRs) were calculated for 63 causes of death. Analysis confirmed a statistically significant increased mortality from cancer of the bronchus, trachea, and lung among men, prior to 1985, who jointly classified with >or=30 years of work duration and >or=30 years since first employed. SMRs for lung cancer after 1985, however, were not statistically significant and were inconsistent across work duration and years since first employed intervals. The study provides no evidence for elevated mortality among Dow Corning workers since the 1991 cohort mortality study. This study describes the updated mortality experience of a large employee cohort from a major silicon-based manufacturer. It illustrates that a well-designed mortality study can be a key component of employee health surveillance efforts in an industrial setting with potential hazardous workplace exposures.

Women's psychosocial outcomes of breast augmentation with silicone gel-filled implants: a 2-year prospective study.

This study examined the experiences of 360 women receiving bilateral breast augmentation with Dow Corning's Silastic MSI (textured) or Silastic II (smooth) gel-filled mammary implants. Before surgery, the women completed a quantitative assessment of their surgical expectations and concerns. At 6, 12, and 24 months postoperatively, they rated their satisfaction with surgery and its specific psychosocial outcomes, their concerns, and benefits-to-risks appraisals of the augmentation. The women reported very high levels of satisfaction with the procedure and its psychosocial outcomes, which did not change over time. Throughout the 2-year period, over 90 percent of the women were satisfied with surgery and their resultant body-image changes. Their concerns about risks, reported by 19 percent before surgery, declined after surgery and remained subsequently stable. Most participants (75 to 85 percent) reported that the benefits of surgery exceeded its risks. Postoperative events such as significant capsular contracture that compromised aesthetic results diminished aspects of satisfaction, whereas less obvious events did not. Systematic analysis of attrition (i.e., missing assessments) did not indicate any biases because of complications or psychosocial outcomes. Evaluation of a possible impact of the publicity surrounding the Food and Drug Administration's voluntary moratorium on the use of silicone gel-filled breast implants, which occurred during the study, revealed a limited effect, if any, on women's psychosocial outcomes. Findings are discussed in relation to the study's methodological strengths and limitations and with respect to the broader context of patient care.

Silicone gel breast implant rupture rates: research issues.

Documenting the rate of rupture of silicone breast implants appears to be deceptively easy. Largely because of the phenomenon of "silent rupture," it isn't. The authors explore the various technical biases (selection, misclassification, and confounding) and methodological problems that have plagued much of the research conducted to date. By means of a series of illustrations, they argue that explantation has limited utility. Noninvasive techniques have to be used to gather the proper type of data on the timing and frequency of these events. Only with the proper incidence data will researchers be able to identify better the different mechanisms underlying implant rupture and the relative importance of each. The authors recommend that better and standardized definitions of implant rupture be developed, that greater recognition be given to the technical biases and a greater effort be made to eliminate them from investigations of implant rupture, and that more research be conducted by multidisciplinary teams. Because of the growing awareness of the complexity of this issue, the authors also recommend that properly constituted advisory teams be used to provide comprehensive oversight of future research projects from beginning to end.