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At least 541 records · Page 30Linked to original sources
PubMed2002

Endoscopy in patients receiving radiation therapy to the thorax.

Radiation therapy for thoracic malignancies is often complicated by radiation-induced esophagitis. Symptoms of radiation esophagitis are nonspecific and include dysphagia, odynophagia, and chest pain. Patients receiving radiation therapy are also at risk for infectious esophagitis, which can be indistinguished clinically from radiation-induced esophagitis. We retrospectively reviewed data on patients who had esophagitis symptoms during or after thoracic radiation therapy and were referred for upper endoscopy. We sought to determine how often infectious esophagitis or cancer was present, as compared to radiation-induced esophagitis alone. Twenty-four upper endoscopies were performed on 16 patients over a three-year period to evaluate esophagitis symptoms. Forty-four percent of the patients endoscoped had infectious esophagitis or recurrent cancer diagnosed by endoscopy. No complications occurred from the procedures. Esophagoscopy is a safe procedure that should be considered, to exclude infection or cancer, in patients who develop esophagitis symptoms during or after thoracic radiation.

Diagnosis, Differential↗
PubMed2000

Computing and visualizing electric potentials and current pathways in the thorax.

The long-term goal of electrocardiography is to relate electric potentials on the body surface with activities in the heart. Many previously reported studies have focused on direct links between heart and body surface potentials. The goals of this study were first to validate computational methods of determining volume potentials and currents with high-resolution experimental measurements and then to use interactive visualization of thoracic currents to understand features of the electrocardiographic fields from measured cardiac sources. We developed both simulation and experimental studies based on a realistic shaped torso phantom containing an isolated, perfused dog heart. Interventions included atrial pacing, single pacing and simultaneously pacing at multiple locations on the ventricles. Simulated torso volume potentials closely matched measured potentials in the torso-tank preparation (mean correlation coefficients of 0.95). Simulation further provided a means of estimating the current field in the torso from the computed torso volume potentials and the local geometric and conductive properties of the medium. Applying these techniques to the torso electric fields under a variety of pacing conditions, we have further demonstrated that thoracic current can provide many insights into the relationship between heart surface potential and body surface potentials. Specifically, we have shown that geometric factors including cardiac source configuration and location play an important role in determining to what extent electric activity in the heart is directly visible on the body surface electrocardiogram. The computation and visualization toolkit we developed in this study to explore current fields associated with cardiac events may provide new insights into electrocardiology.

Action Potentials↗
PubMed2000

JNK and decapentaplegic signaling control adhesiveness and cytoskeleton dynamics during thorax closure in Drosophila.

One of the fundamental events in metamorphosis in insects is the replacement of larval tissues by imaginal tissues. Shortly after pupariation the imaginal discs evaginate to assume their positions at the surface of the prepupal animal. This is a very precise process that is only beginning to be understood. In Drosophila, during embryonic dorsal closure, the epithelial cells push the amnioserosa cells, which contract and eventually invaginate in the body cavity. In contrast, we find that during pupariation the imaginal cells crawl over the passive larval tissue following a very accurate temporal and spatial pattern. Spreading is driven by filopodia and actin bridges that, protruding from the leading edge, mediate the stretching of the imaginal epithelia. Although interfering with JNK (Jun N-terminal kinase) and dpp (decapentaplegic) produces similar phenotypic effects suppressing closure, their effects at the cellular level are different. The loss of JNK activity alters the adhesion properties of larval cells and leads to the detachment of the imaginal and larval tissues. The absence of dpp signaling affects the actin cytoskeleton, blocks the emission of filopodia, and promotes the collapse of the leading edge of the imaginal tissues. Interestingly, these effects are very similar to those observed after interfering with JNK and dpp signaling during embryonic dorsal closure.

Animals↗
PubMed1996

Changes in myocardial and circulating atrial natriuretic peptide following thorax irradiation in rat.

The effect of thoracic irradiation on plasma and myocardial atrial natriuretic peptide (ANP) was studied in rat. The animals were irradiated with a dose of 20 Gy to the heart. After, 1, 12, 26 and 52 weeks, plasma ANP concentration and ANP in atrial and ventricular myocardium were determined. Plasma ANP levels were increased to 140% of control values from 3 months onwards and remained elevated for the next 9 months. Atrial ANP concentrations remained unaltered in the first 6 months post-treatment, but became reduced after 1 year to 37% of control values. Ventricular ANP concentration in irradiated rats rose 20-fold within 3 months, remained at that level up to 6 months and fell to six times control values at 1 year. An inverse relationship between plasma and atrial ANP concentration was found, while plasma and ventricular ANP concentrations were positively correlated. The results obtained in the present study suggest that in radiation-induced heart disease, plasma ANP concentration can be used as a marker for early stage cardiac dysfunction.

Animals↗