Publications

There is increased interest in and use of cardiac computed tomographic and magnetic resonance imaging as the technology continues to improve. We have many small single-center trials on the diagnostic accuracy of these techniques, but no studies that show a patient benefit from testing. The American College of Cardiology has recently tackled the "appropriateness challenge" for imaging tests, including computed tomographic and magnetic resonance imaging. The importance of outcomes data and risks of continuing our investment in computed tomography without outcomes data on benefits for patient care are discussed in this paper.

Matrix metalloproteinases (MMPs) are central to the development and progression of dysfunctional ventricular remodeling after tissue injury. We studied 6 month old heterozygous mice with cardiac-specific transgenic expression of active MMP-2 (MMP-2 Tg). MMP-2 Tg hearts showed no substantial gross alteration of cardiac phenotype compared to age-matched wild-type littermates. However, buffer perfused MMP-2 Tg hearts subjected to 30 min of global ischemia followed by 30 min of reperfusion had a larger infarct size and greater depression in contractile performance compared to wild-type hearts. Importantly, cardioprotection mediated by ischemic preconditioning (IPC) was completely abolished in MMP-2 Tg hearts, as shown by abnormalities in mitochondrial ultrastructure and impaired respiration, increased lipid peroxidation, cell necrosis and persistently reduced recovery of contractile performance during post-ischemic reperfusion. We conclude that MMP-2 functions not only as a proteolytic enzyme but also as a previously unrecognized active negative regulator of mitochondrial function during superimposed oxidative stress.

Allergic and parasitic worm immunity is characterized by infiltration of tissues with interleukin (IL)-4- and IL-13-expressing cells, including T-helper-2 cells, eosinophils and basophils. Tissue macrophages assume a distinct phenotype, designated alternatively activated macrophages. Relatively little is known about the factors that trigger these host responses. Chitin, a widespread environmental biopolymer of N-acetyl-beta-D-glucosamine, provides structural rigidity to fungi, crustaceans, helminths and insects. Here, we show that chitin induces the accumulation in tissue of IL-4-expressing innate immune cells, including eosinophils and basophils, when given to mice. Tissue infiltration was unaffected by the absence of Toll-like-receptor-mediated lipopolysaccharide recognition but did not occur if the injected chitin was pre-treated with the IL-4- and IL-13-inducible mammalian chitinase, AMCase, or if the chitin was injected into mice that overexpressed AMCase. Chitin mediated alternative macrophage activation in vivo and the production of leukotriene B(4), which was required for optimal immune cell recruitment. Chitin is a recognition element for tissue infiltration by innate cells implicated in allergic and helminth immunity and this process can be negatively regulated by a vertebrate chitinase.

STUDY DESIGN

This is a 4-month randomized controlled trial to evaluate the effect of chair design on neck/shoulder pain among sewing machine operators.

OBJECTIVE

Determine whether a chair with a curved seat pan leads to improved changes in monthly neck/shoulder pain scores compared with a control intervention.

SUMMARY OF BACKGROUND DATA

Sewing machine operators experience a high prevalence and severity of neck and shoulder pain in comparison to other working populations probably due to the sustained shoulder abduction and neck and upper back flexion required of the task. An adjustable height task chair that supports a forward sitting posture may reduce these posture-related risk factors and reduce neck/shoulder pain.

MATERIALS AND METHODS

A total of 277 sewing machine operators with neck/shoulder pain were assigned to receive 1) miscellaneous items (control group), 2) a chair with a flat seat pan plus miscellaneous items, or 3) a chair with a curved seat pan plus miscellaneous items. Participants completed a monthly questionnaire assessing neck/shoulder pain severity.

RESULTS

Based on estimates of pain score changes from a repeat-measures linear regression, participants who received the flat seat chair experienced a decline in pain of 0.14 (95% confidence interval, 0.07-0.22) points per month compared with those in the control group, while those who received the curved seat experienced a decline of 0.34 (95% confidence interval, 0.28-0.41) points per month compared with those in the control group. These estimates did not change after adjustment for potential covariates.

CONCLUSIONS

These findings demonstrate that an adjustable height task chair with a curved seat pan can reduce neck and shoulder pain severity among sewing machine operators.

Serum mast cell tryptase levels are used as a diagnostic criterion and surrogate marker of disease severity in mastocytosis. Approximately 29% of the healthy population lacks alpha tryptase genes; however, it is not known whether lack of alpha tryptase genes leads to variability in tryptase levels or impacts on disease severity in mastocytosis. We have thus analyzed tryptase haplotype in patients with mastocytosis, computing correlations between haplotype and plasma total and mature tryptase levels; and disease category. We found: (1) the distribution of tryptase haplotype in patients with mastocytosis appeared consistent with Hardy-Weinberg equilibrium and the distribution in the general population; (2) the disease severity and plasma tryptase levels were not affected by the number of alpha or beta tryptase alleles in this study; and (3) information about the tryptase haplotype did not provide any prognostic value about the severity of disease. Total and mature tryptase levels positively correlated with disease severity, as well as prothrombin time and partial thromboplastin time, and negatively correlated with the hemoglobin concentration.