Esophageal perforation. An unusual presentation with a benign clinical course

A case of esophageal perforation occurring in a 75-year-old man is presented. The clinical presentation was benign and the diagnosis of esophageal perforation was made incidental to an upper gastrointestinal barium examination. Conservative management consisting of nasogastric suctioning, antibiotics and antacids was effective in minimizing the clinical course. This represents a rare instance of a successful nonsurgical approach to esophageal perforation.     

Dexamethasone 21-mesylate: an affinity label of glucocorticoid receptors from rat hepatoma tissue culture cells

We recently described the biological properties of an alpha-keto mesylate derivative of cortisol, cortisol-Mes. Cortisol-Mes exhibited long-term antiglucocorticoid activity, but there was no firm evidence that this activity was irreversible or receptor-mediated. Here we report that dexamethasone mesylate (Dex-Mes), which is the alpha-keto mesylate derivative of the more active glucocorticoid dexamethasone, is a candidate for a steroid-specific affinity label of glucocorticoid receptors. Dex-Mes is relatively stable, like cortisol-Mes, but possesses greater whole-cell antiglucocorticoid activity. However, Dex-Mes also possesses partial agonist activity, which is expressed at somewhat higher concentrations of Dex-Mes than the antagonist activity. Dex-Mes is more efficient than cortisol-Mes in competing for dexamethasone binding to glucocorticoid receptors. Furthermore, Dex-Mes is effective at lower concentrations than cortisol-Mes in causing long-term apparently irreversible antiglucocorticoid effects in whole and broken cells. The cell-free effect of Dex-Mes is specifically prevented by coincubation with an excess of cortisol. These facts argue that the apparently irreversible effects of Dex-Mes are steroid mediated. [3H]Dex-Mes has been used to identify a glucocorticoid-specific, covalently labeled fraction on sodium dodecyl sulfate/polyacrylamide gels with a molecular weight of approximately 85,000. Thus Dex-Mes appears to have been established as an affinity label for glucocorticoid receptors.     

Relationship of somatic cell count and cell volume analysis of goat's milk to intramammary infection with coagulase-negative staphylococci

The prevalence of intramammary infection in 4 commercial goat herds was studied in conjunction with electronic somatic cell count and volume analysis determined using a Coutler Counter and volume analyser. Neither streptococci nor mycoplasma were isolated from any half and the prevalence of intramammary infection with Staphylococcus aureus ranged from 0 to 3% between herds. For coagulase-negative staphylococci the range from infected halves was 36-71%. There was no significant difference between the mean total microscopic somatic cell count for halves infected with coagulase-negative staphylococci and those free from infection. A similar trend was observed for electronic somatic cell counts although the mean electronic cell count was greater than the mean total microscopic count on the 2 occasions that they were compared. The correlation coefficients between the 2 cell counting methods were 0.86 and 0.94. Between herds there were significant differences in mean electronic somatic cell count, with herd means ranging from 438 x 103 to 1684 x 103 cells/ml. In 2 of the 4 herds studied, milk samples from halves infected with coagulase-negative staphylococci had a significantly higher prevalence of cell volume distributions with a modal cell volume between 65 mu 3 and 100 mu 3. This was attributed to a higher proportion of polymorphonuclear neutrophils. Use of electronic somatic cell count and cell volume analysis were considered of little value in predicting infection caused by coagulase-negative staphylococci as there was a high proportion of false negative and false positive predictions.     

Calibration and evaluation of nitric acid and ammonia permeation tubes by UV optical absorption

An ultraviolet (UV) optical absorption system has been developed for absolute calibrations of nitric acid (HNO3) and ammonia (NH3) permeation tube emission rates. Using this technique, dilute mixtures containing NH3 or HNO3, both of which interact strongly with many surfaces, are accurately measured at levels below a part per million by volume. This compact and portable instrument operates continuously and autonomously to rapidly (<1 h) quantify the emission of trace gases from permeation devices that are commonly used to calibrate air-monitoring instruments. The output from several HNO3 and NH3 permeation tubes, with emission rates that ranged between 13 and 150 ng/min, was examined as a function of temperature, pressure, and carrier gas flow. Absorptions of 0.015% can be detected which allows a precision (3sigma) of +/-1 ng/min for the HNO3 and NH3 permeation tubes studied here. The accuracy of the measurements, which relies on published UV absorption cross sections, is estimated to be +/-10%. Measurements of permeation tube emission rates using ion chromatography analysis are made to further assess measurement accuracy. The output from the HNO3 and NH3 permeation tubes examined here was stable over the study period, which ranged between 3 months and 1 year for each permeation tube.     

Moderating effects of sensitivity to punishment and sensitivity to reward on associations between marijuana effect expectancies and use.

The study examined associations between sensitivity to reward (SR), sensitivity to punishment (SP), positive and negative expectancies, and marijuana use in a college sample (N = 809). Marijuana users (n = 227) reported lower SP and greater SR than nonusers. SR attenuated the association between SP and the probability of marijuana use. SP attenuated the association between positive expectancies and the probability of marijuana use as well as the frequency of use among users. SP potentiated the association between negative expectancies and use. The results indicate that SP and SR have interactive effects and that SP moderates the strength of positive and negative cues for risk behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Advances in Space Traveling-Wave Tubes for NASA Missions

Significant advances in the performance and reliability of traveling-wave tubes (TWTs) utilized in amplifying space communication signals for NASA missions have been achieved over the last three decades through collaborative efforts between NASA and primarily L-3 Communications Electron Technologies, Inc. (L-3 ETI). This paper summarizes some of the key milestones during this period and includes development of TWTs for the Communications Technology Satellite, Cassini, and Lunar Reconnaissance Orbiter missions. Technical advances in computer modeling, design techniques, materials, and fabrication have enabled power efficiency to increase by almost 40% and the output power/mass figure-of-merit to increase by an order of magnitude during this period.