The CT halo sign: a new finding in intestinal lymphangiectasia

A "halo sign" has been described in patients with Crohn disease, ulcerative colitis, radiation enteritis, ischemic colitis, and pseudomembranous colitis. This sign is characterized by an inner ring of low CT attenuation surrounded by a higher attenuation outer ring. We present a patient with primary intestinal lymphangiectasia in whom CT demonstrated a halo sign correlated with mucosal biopsy.     

Current practices of preoperative bowel preparation among North American colorectal surgeons

In North America, the rate of infections following colorectal surgery decreased after the introduction of oral antibiotic bowel preparation against colonic microflora. Eight hundred eight board-certified colorectal surgeons were surveyed for their current bowel preparation practices before elective procedures. The 471 responders (58%) all use mechanical preparation: oral polyethylene glycol solution (70.9% of the respondents), oral sodium phosphate solution with or without bisacodyl (28.4%), and "traditional" methods of dietary restriction, cathartics, and enemas (28.4%). Most surgeons (86.5%) add oral and parenteral antibiotics to the regimen; 11.5% add only parenteral antibiotics, 1.1% add only oral antibiotics, and 0.9% add no antibiotics. Generally (77.8% of cases), oral neomycin and erythromycin or metronidazole are combined with a perioperative parenteral antibiotic. Most individuals start the preparation as outpatients the day before surgery, and the parenteral drugs are added to the regimen 1-2 hours before the procedure. The use of outpatient bowel preparation is increasing; however, patient selection is critical, and education is needed to reduce the rate of complications.     

Attitudes, beliefs, and practices regarding smoking and smoking cessation among African-American physicians and dentists

African-American physicians and dentists in metropolitan Atlanta were surveyed to assess smoking cessation practices and perceptions. Questionnaires were mailed to 373 physicians and 90 dentists. A total of 154 questionnaires were returned, for an overall response rate of 33.3%. More physicians than dentists considered smoking a "very serious" threat to patients' health, and physicians were more likely to document smoking status in charts and to counsel smokers to quit. Physicians also were approached more frequently by patients seeking cessation advice. Both types of practitioners considered the nicotine patch, formal cessation programs, and behavior modification/psychotherapy to be among the most effective cessation methods, and nicotine gum and acupuncture to be among the least effective. These results indicate African-American physicians are much more involved than dentists in promoting smoking cessation among patients. Advice of health professionals generally is viewed as a powerful influence for African-American patients. Further work is needed to utilize fully the power of health care providers, especially dentists, in the fight against tobacco-related morbidity and mortality.     

Building laminate veneers and fixed bridges with polymer glass technology

A new type of material is being introduced to American dentistry. The material is a polymer glass, tested in Europe as Artglass. The material is purported to be equal to or better than porcelain for esthetic dentistry. The strength, color translucency, and color vitality allow minimal destruction of enamel for esthetics. An Artglass occlusal is less abrasive to enamel than porcelain and approximates gold. The characteristics of this material system introduces "minimal invasive dentistry" to routine dental repair and reconstruction. A case study of the senior author's reconstruction of his anterior teeth is presented.     

Effect of antacid on bioavailability of a sustained-release theophylline preparation

The effect of coadministration of an antacid on bioavailability of a sustained-release theophylline tablet preparation (Theo-Dur) was studied by crossover comparison in five young, healthy, nonsmoking volunteers. Water 90 ml, or "high potency" aluminum-magnesium hydroxide antacid (Mylanta II) 10 ml and water 80 ml were administered concurrently with sustained-release theophylline 600 mg. Eleven blood samples were collected over the next 24 hours. Serum was analyzed with high pressure liquid chromatography technique to determine theophylline concentration. Peak serum concentration (Cmax) and time to peak concentration (tmax) were determined, and area under the 24-hour serum concentration-time curve (AUC) was calculated by the trapezoidal rule for each subject at each study interval. The Student's paired t-test was used to compare Cmax, tmax, and AUC for both treatments. A uniform difference was found between groups in Cmax. Cmax was higher in subjects when treated with the antacid (10.45 +/- 3.03 vs. 8.30 +/- 2.90 micrograms/ml, p less than 0.05) than when given theophylline alone. The mean tmax for the two treatments did not differ (10.4 +/- 1.67 h-combination vs. 10.8 +/- 1.1 h-theophylline, p greater than 0.05). Likewise, mean AUC was unchanged by the coadministration of antacid (140.65 +/- 41.6 micrograms/ml.h--combination vs. 155.13 +/- 46.6 micrograms/h--theophylline, p greater than 0.05). The use of a high-potency antacid product did not decrease the extent of theophylline absorption from this sustained-release product, but did increase Cmax and, presumably, rate of absorption. High-potency aluminum-magnesium antacids can probably be used in combination with this sustained-release theophylline tablet without detriment to therapy.     

Oral-contraceptive-induced hypertension after adrenalectomy and hypophysectomy

The cause of oral-contraceptive-induced hypertension in certain susceptible subjects is obscure. We describe a woman who was receiving replacement doses of fludrocortisone acetate after adrenalectomy and hypophysectomy who developed high blood pressure while ingesting an estrogen-containing oral contraceptive. Renin substrate level was increased, but renin activity was suppressed and unresponsive to tilting. The patient developed a markedly exaggerated natriuresis when infused with saline. Both blood pressure and her responses to infused sodium and tilting normalized after discontinuance of the oral contraceptive medication. In this adrenalectomized patient, the estrogenic component of the pill acting synergistically with a fixed ("nonsuppressible") replacement dose of mineralocorticoid seems to have caused a volume-related hypertension.     

Tools for software verification

Developing tools that are able to perform automatic verification on realistic models of software systems is one of the main challenges facing the formal methods community. We briefly review the research area and introduce three papers selected from the Seventeenth International Conference on Tools and Algorithms for the Construction and Analysis of Systems (tacas 2011).     

Effect of cognitive load on speech prosody in aviation: Evidence from military simulator flights

Mental overload directly affects safety in aviation and needs to be alleviated. Speech recordings are obtained non-invasively and as such are feasible for monitoring cognitive load. We recorded speech of 13 military pilots while they were performing a simulator task. Three types of cognitive load (load on situation awareness, information processing and decision making) were rated by a flight instructor separately for each flight phase and participant. As a function of increased cognitive load, the mean utterance-level fundamental frequency (F0) increased, on average, by 7 Hz and the mean vocal intensity increased by 1 dB. In the most intensive simulator flight phases, mean F0 increased by 12 Hz and mean intensity, by 1.5 dB. At the same time, the mean F0 range decreased by 5 Hz, on average. Our results showed that prosodic features of speech can be used to monitor speaker state and support pilot training in a simulator environment.     

Activation and adherence of lyophilized human platelets on canine vessel strips in the Baumgartner perfusion chamber

The Baumgartner perfusion technique was used to test the ability of rehydrated lyophilized human platelets to adhere to the thrombogenic surface of a denuded arterial vessel segment and to undergo platelet activation under conditions of high shear. Twenty preparations of washed platelets were stabilized by 1-hour or 2-hour exposure to paraformaldehyde before freeze-drying in a Virtis 600 lyophilizer. The response of these fixed-dried preparations was compared with that of non-fixed platelets in fresh citrated whole blood. The outcome of each perfusion experiment was quantified in photomicrographs by morphometric estimation of the percent area of the vessel segment covered by adherent platelets after immunofluorescent staining with monoclonal antibodies to glycoprotein Ib (CD42) or glycoprotein IIbIIIa (CD41a). Evidence of activation in nonadherent platelets was examined by flow cytometry for CD62 and GP53 expression. In addition, thromboxane B2 was measured by radioimmunoassay as an index of platelet responsiveness to activation conditions during perfusion. The percent vessel coverage observed with lyophilized platelets in recombined whole blood was somewhat less than that of platelets in fresh whole blood (39% vs 73%, respectively). In other perfusion experiments performed with non-denuded vessel segments, the percent coverage was reduced by half or more for both types of platelet preparation. Scanning electron microscopy confirmed that the lyophilized platelets did not adhere to areas of intact endothelium. Furthermore, the lyophilized platelets showed a small-but-significant rise in CD62 or CD63 activation antigen expression and generated thromboxane B2 at about one third the rate of fresh platelets in these perfusion experiments. The thromboxane generation during perfusion was inhibited in fresh or lyophilized platelet preparations by pretreatment with indomethacin or PGE-1. We interpret these data as evidence of the ability of our lyophiilized platelet preparations to respond at least partially to physiologic stimuli and to adhere to appropriate thrombogenic sites to support hemostasis.     

Comparison of femoral blood gases and muscle near-infrared spectroscopy at exercise onset in humans

We hypothesized that near-infrared spectroscopy (NIRS) measures of hemoglobin and/or myoglobin O2 saturation (IR-SO2) in the vascular bed of exercising muscle would parallel changes in femoral venous O2 saturation (SfvO2) at the onset of leg-kicking exercise in humans. Six healthy subjects performed transitions from rest to 48 +/- 3 (SE)-W two-legged kicking exercise while breathing 14, 21, or 70% inspired O2. IR-SO2 was measured over the vastus lateralis muscle continuously during all tests, and femoral venous and radial artery blood samples were drawn simultaneously during rest and during 5 min of exercise. In all gas-breathing conditions, there was a rapid decrease in both IR-SO2 and SfvO2 at the onset of moderate-intensity leg-kicking exercise. Although SfvO2 remained at low levels throughout exercise, IR-SO2 increased significantly after the first minute of exercise in both normoxia and hyperoxia. Contrary to the hypothesis, these data show that NIRS does not provide a reliable estimate of hemoglobin and/or O2 saturation as reflected by direct femoral vein sampling.