Publications

We report a case of a primary right ventricular leiomyosarcoma in a 58-year-old woman diagnosed by endomyocardial biopsy. Clinical findings included a 5-year history of atypical chest pain and atrial fibrillation as well as a 30-lb weight loss. A ventricular mass was identified by echocardiography and magnetic resonance imaging, and an endomyocardial biopsy was performed. Biopsy was guided by right ventriculography, which revealed a mobile mass in the cavity of the right ventricle. Light microscopy revealed a fasciculated, spindle cell sarcoma, most consistent with leiomyosarcoma, and immunohistochemical staining for muscle-specific actin was strongly positive in nearly all tumor cells, confirming its myogenous differentiation. Endomyocardial biopsy provided a definitive tissue diagnosis of this rare primary malignant cardiac neoplasm without the need for a surgical procedure.

Nuclear expression and consequent biological action of the eukaryotic NF-kappa B transcription factor complex are tightly regulated through its cytoplasmic retention by an ankyrin-rich inhibitory protein termed I kappa B alpha. I kappa B alpha specifically binds to and masks the nuclear localization signal of the RelA subunit of NF-kappa B, thereby effectively sequestering this transcription factor complex in the cytoplasm. Specific cellular activation signals lead to the rapid proteolytic degradation of I kappa B alpha and the concomitant nuclear translocation of NF-kappa B. However, the precise biochemical mechanisms underlying the inhibitory effects of I kappa B alpha on RelA and its inducible pattern of degradation remain unclear. By using HeLa cells transfected with various cDNAs end-coding epitope-tagged mutants of I kappa B alpha, our studies demonstrate the following: (i) sequences within the 72-amino-acid N-terminal region of I kappa B alpha are required for tumor necrosis factor alpha (TNF-alpha)-induced degradation but are fully dispensable for I kappa B alpha binding to and inhibition of RelA; (ii) serine residues located at positions 32 and 36 within the N-terminal region of I kappa B alpha represent major sites of induced phosphorylation (substitution of these serine residues with alanine abrogates TNF-alpha-induced degradation of I kappa B alpha); (iii) the C-terminal 40 residues of I kappa B alpha (amino acids 277 to 317), which include a PEST-like domain, are entirely dispensable for TNF-alpha-induced degradation and inhibition of RelA; (iv) a glutamine- and leucine-rich (QL) region of I kappa B alpha located between residues 263 and 277 and overlapping with the sixth ankyrin repeat is required for both inducible degradation and inhibition of RelA function; (v) regulation of I kappa B alpha degradation by this QL-rich region appears to occur independently of phosphorylation at serines 32 and 36. These findings thus indicate that I kappa B alpha is generally organized within distinct modular domains displaying different functional and regulatory properties. These studies have also led to the identification of a novel class of dominant-negative I kappa B alpha molecules that retain full inhibitory function on NF-kappa B yet fail to undergo stimulus-induced degradation. These molecules, which lack N-terminal sequences, potently inhibit TNF-alpha-induced activation of the human immune deficiency virus type 1 kappa B enhancer, thus indicating their possible use as general inhibitors of NF-kappa B.

STUDY OBJECTIVE

Identify risk factors for work disability among adults with asthma treated by pulmonary and allergy specialists.

DESIGN

Cross-sectional survey, including retrospective work history data.

PARTICIPANTS

Sixty-eight pulmonary and 16 allergy internal medicine subspecialists maintaining a registry of patient visits for asthma; 698 registered patients aged 18 to 50 years, of whom 601 (86%) were studied.

MEASURES

Computer-assisted, telephone-administered structured interview assessing asthma severity, perceived general health status, asthma quality of life, demographics, and work history. Complete work disability defined as total work cessation attributed to asthma; partial work disability defined as change in job, duties, or reduction in work hours attributed to asthma.

RESULTS

Complete cessation of work due to asthma was reported by 40 (7%; 95% confidence interval [CI], 5 to 9%) and partial work disability by 53 (10%; 95% CI, 7 to 12%) of 550 subjects with a history of labor force participation. Severity of asthma score predicted both complete disability (odds ratio [OR], 7.9; 95% CI, 4.2 to 15 per 10-point increment) and partial disability (OR 2.6; 95% CI, 1.6 to 4.2). Taking illness severity into account, job conditions, occupation, and work exertion carried a combined disability OR of 3.9 (95% CI, 1.7 to 8.6).

CONCLUSIONS

Work disability is common among adults with asthma receiving specialist care. Severity of disease is a powerful predictor, but not the sole predictor of disability in this group. Working conditions, including job-related exposures, are associated with added disability risk even after taking illness severity into account.