Measurement of 23Na(α,p)26Mg at Energies Relevant to 26Al Production in Massive Stars.

26Al is an important radioisotope in astrophysics that provides evidence of ongoing nucleosynthesis in the Galaxy. The 23Na(α, p)26Mg reaction has been identified by a sensitivity study as being one of the most important reactions for the production of 26Al in the convective C/Ne burning shell of massive stars. Owing to large uncertainties in previous experimental data, model calculations are used for the reaction rate of 23Na(α, p)26Mg in this sensitivity study. Current experimental data suggest a reaction rate a factor of ∼40 higher than model calculations. However, a new measurement of this reaction cross section has been made in inverse kinematics in the energy range E(c.m.)=1.28-3.15 MeV at TRIUMF, and found to be in reasonable agreement with the model calculation. A new reaction rate is calculated and tight constraints on the uncertainty in the production of 26Al, due to this reaction, are determined.

The histology of experimental pleural injury with tetracycline, empyema, and carrageenan.

Models of pleural injury were established with intrapleural tetracycline, intrapleural carrageenan, and empyema in New Zealand White rabbits to evaluate histologically the pleural inflammatory response from 3 to 90 days. Both tetracycline and empyema models produced increases in the pleural connective tissue layers both above and below the fibroelastic membrane associated with angiogenesis and lymphangiogenesis. The influx of fibroblasts from the pleural surface into acellular fibrin strands formed adhesions between the visceral and the parietal pleurae. Injury to the mesothelial cell ranged from a cuboidal transition to total desquamation with the degree of mesothelial injury associated with the amount of fibrin adherence and the propensity toward fibrosis at 90 days. Intervention to promote the resolution of pleural inflammation without fibrosis should be directed toward preservation of the mesothelial surface, removal of pleural fibrin, and inhibition of fibroblast growth and chemotaxis.

A prospective comparison of IMV and T-piece weaning from mechanical ventilation.

Two hundred (200) consecutive medical and surgical patients requiring mechanical ventilation were entered into a prospective randomized trial of weaning by either intermittent mandatory ventilation (IMV) or T-piece. Patients in these groups were of similar age and sex and had the same total ventilation time (TVT). The study design provided equal time for each weaning mode after specific criteria for oxygenation and ventilation were satisfied (PaO2 greater than 55 mm Hg on FIO2 less than 0.5; VE less than 12 L/min and two of the following four parameters: MVV greater than 2 VE, VT greater than 5 ml/kg, FVC greater than 10 ml/kg, NIF less than or equal to -20 cm H2O). Of the original 200 patients 165 were entered into the weaning phase; 35 patients were withdrawn prior to weaning due to the discretion of the attending physician or protocol error. Weaning time was not different between the IMV (5.3 +/- 1.2 h, mean +/- SEM) and T-piece groups (5.9 +/- 1.4 h, p = NS). Of the 165 patients, 155 (93 percent) were weaned successfully by protocol, 79 in the IMV and 76 in the T-piece group. Of 155 patients, 136 (88 percent) were weaned on the first attempt by protocol. Of the 19 who were not weaned, 11 were weaned successfully on the second and five on the third trial; three patients required three-day weans. We conclude that clinically stable patients who require short-term mechanical ventilation and meet standard bedside weaning criteria can be weaned efficiently by protocol using either IMV or T-piece techniques.

Protected transbronchial needle aspiration and protected specimen brush in the diagnosis of pneumonia.

Protected transbronchial needle aspiration (PTBNA) of pneumonic lung theoretically could bypass dislodged upper respiratory tract flora, a potential source of contamination of protected specimen brush (PSB) cultures. To evaluate the usefulness of PSB and PTBNA in establishing the etiology of pneumonia, we prospectively studied 20 patients with acute bacterial pneumonia not receiving antibiotics. After informed consent, patients had fiberoptic bronchoscopy under fluoroscopy to localize the pneumonia, and specimens were obtained by the PSB. The protective plug of a specially devised needle for PTBNA was pneumatically dislodged and aspiration was performed within the infiltrate under fluoroscopy. Quantitative cultures were plated immediately for aerobes, anaerobes, and Legionella. Greater than 4 X 10(3) organisms/brush or 1 X 10(4) organisms/ml needle aspirate were considered to be consistent with infection. The results using PSB and PTBNA were compared in 15 of 20 patients in whom a definitive diagnosis (positive blood or pleural fluid culture) or presumptive diagnosis (expectorated sputum culture, clinical characteristics, and response to specific therapy) was established. The PSB and PTBNA cultures on uninfected control subjects (n = 5) being bronchoscoped for other reasons were negative. The PSB and PTBNA were each diagnostic in 2 of the 5 patients with definitive diagnoses. In the group with a presumptive diagnosis (n = 10), PSB was diagnostic in 7 of 10 and PTBNA in 9 of 10. The overall (definitive plus presumptive) diagnostic yield was 60% for PSB and 73% for PTBNA. Multiple organisms were isolated in high concentrations in 53% of the patients. The most common organisms recovered in addition to the primary pathogen was alpha hemolytic streptococci.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspergilloma in sarcoid and tuberculosis.

The presentation, treatment, and outcome of 28 patients with aspergilloma and cavitary tuberculosis (14) and sarcoidosis (14) were compared. Patients with tuberculosis had localized disease (12 of 14, 86 percent), whereas patients with sarcoidosis had diffuse disease (1 of 14, 7 percent localized). Results indicated that patients with either sarcoid or tuberculosis who developed an aspergilloma had a poor prognosis over the next decade. Patients with sarcoid appeared to have a worse short-term prognosis; surgical resection in the tuberculosis patients may have contributed to their better short-term survival.

Pleuropulmonary complications of enteral tube feedings. Two reports, review of the literature, and recommendations.

Enteral tube feeding is an attractive alternative to intravenous alimentation for nutritional support. As previously used nasogastric tubes have been replaced with narrow-bore nasogastric tubes, the spectrum of complications seen with these devices has changed. We report a previously undescribed event associated with narrow-bore nasogastric tube feeding, review the literature, noting predisposing factors and complications, and suggest guidelines to avoid pitfalls of insertion and the ensuing adverse effects.