To evaluate the role of mediastinal irradiation (RT) following surgery for invasive thymomas, a clinical and pathologic review of 117 patients with the diagnosis of thymoma was completed. Fourteen cases were excluded because of the lack of histologic criteria for a thymic tumor, and the remaining 103 were classified according to a staging system as follows: stage I, completely encapsulated (43); stage II, extension through the capsule or pericapsular fat invasion (21); stage III, invasion of adjacent structures (36); and stage IV, thoracic dissemination or metastases (3). The 5-year actuarial survival and relapse-free survival rates were 67% and 100% for stage I, 86% and 58% for stage II, and 69% and 53% for stage III. No recurrences occurred among stage I patients after total resection without RT. However, eight of 21 patients with invasive (stage II or III) thymomas had mediastinal recurrence as the first site of failure following total resection without RT. The 5-year actuarial mediastinal relapse rate of 53% in this group compares unfavorably with the mediastinal relapse rate seen among stage II or III cases following total resection with RT (0%) or following subtotal resection/biopsy with RT (21%). Despite attempted salvage therapy, five of eight patients with mediastinal relapse following total resection alone died of progressive disease. No significant difference was observed in the local relapse rate, overall relapse rate, or survival between those patients undergoing biopsy and RT v subtotal resection and RT for invasive thymomas (stages II and III). Total resection alone appears to be inadequate therapy resulting in an unacceptably high local failure rate with poor salvage therapy results.

Recently, we reported an increased incidence of soft tissue sarcomas in a biopsy population of cats at the University of Pennsylvania School of Veterinary Medicine.8 Epidemiologic evidence indicated that this increase coincided with enactment of a Pennsylvania state law requiring rabies vaccination of cats, and the majority of these sarcomas were in areas routinely used by veterinarians for vaccination (dorsal neck/ interscapular, dorsolateral thorax, hindlimb, dorsal lumbar). Many of the sarcomas were surrounded and partially infiltrated by an inflammatory infiltrate of lymphocytes and macrophages. A similar inflammatory infiltrate had previously been reported to occur subsequent to subcutaneous injection of rabies vaccines in cats and dogs.' Furthermore, aluminum was identified in macrophages surrounding the sarcomas by electron probe x-ray microanalysis. Aluminum, in the form of aluminum hydroxide or aluminum phosphate, is an adjuvant in approximately 20% of vaccines for feline use. It was our interpretation that persistence of the inflammatory and immunologic reactions associated with the presence of the aluminum in the vaccination sites predisposes the cat to a derangement of its fibrous connective tissue repair response, occasionally leading to neoplasia. It is now apparent that vaccine-associated sarcomas are being recognized throughout the United S t a t e~.~. '~ Here we describe the histology and immunohistochemical marker staining of postvaccinal sarcomas. We hope this will increase the recognition of these sarcomas by pathologists and shed some light on the pathogenesis of this intriguing syndrome.The information presented here is based on 46 feline sarcomas in the surgical pathology files of the School of Veterinary Medicine of the University of Pennsylvania. These sarcomas were received during 1991 and 1992 and were documented by Veterinarians responding to an epidemiological survey to have occurred at sites at which there had been previous vaccination (unpublished data). Sarcomas were fixed in 10% formalin and routinely processed for histologic examination. Five-micrometer sections were cut from paraffinembedded blocks and stained with hematoxylin and eosin. A previously described avidin-biotin immunoperoxidase complex technique was used on representative sarcoma^.^ Briefly, paraffin-embedded sections, 5 pm in thickness, were cut and carefully melted at 58-60 C. After deparaffinization and rehydration, slides were incubated in 0.3% H 2 0 2 in absolute methanol for 45 minutes. Sequential incubations in 20% normal goat serum (30 minutes), primary antiserum (1 hour at room temperature or overnight at 4 C), secondary biotinylated antibody (45 minutes), and avidin-biotin complex reagent (45 minutes) followed. Sections were then exposed to the chromagen reaction solution (0.035% diaminobenzidine in 10 ml Tris buffer, filtered, and brought to 0.03% H202) for 5 minutes. Sections were counterstained in Mayer's hematoxylin, dehydrated, cleared, and mounted.For certain antisera (see below), sections were pretr...

Social media poses a threat to public health by facilitating the spread of misinformation. At the same time, however, social media offers a promising avenue to stem the distribution of false claims-as evidenced by real-time corrections, crowdsourced fact-checking, and algorithmic tagging. Despite the growing attempts to correct misinformation on social media, there is still considerable ambiguity regarding the ability to effectively ameliorate the negative impact of false messages. To address this gap, the current study uses a meta-analysis to evaluate the relative impact of social media interventions designed to correct health-related misinformation (k = 24; N = 6,086). Additionally, the meta-analysis introduces theory-driven moderators that help delineate the effectiveness of social media interventions. The mean effect size of attempts to correct misinformation on social media was positive and significant (d = 0.40, 95% CI [0.25, 0.55], p =.0005) and a publication bias could not be excluded. Interventions were more effective in cases where participants were involved with the health topic, as well as when misinformation was distributed by news organizations (vs. peers) and debunked by experts (vs. non-experts). The findings of this meta-analysis can be used not only to depict the current state of the literature but also to prescribe specific recommendations to better address the proliferation of health misinformation on social media.

Margins > or =10 mm independently predicted longer LRFI and are optimal for extremity STS resection. Adjuvant radiotherapy should be considered for all STS resected with margins <10 mm, and margin width should be considered when reporting and interpreting LR outcomes for these patients.