Significance of 'Langer's axillary arch' in axillary dissection

The axillary arch is reported to occur in 7% of the population, but in our experience has only been observed in 0.25%. The anatomical features are described and its importance in axillary dissection is indicated. In addition, its relevance to the prevention of lymphoedema and to the construction of latissimus dorsi flaps is discussed. The axillary arch should be considered in the differential diagnosis of axillary swellings.     

Extreme bradycardia during sleep apnea caused by myxedema

A 52-year-old man with myxedema was evaluated for anterior chest pain that was considered to be compatible with myocardial ischemia. The night after admission he developed extreme bradycardia, hypotension, and apneic episodes lasting up to 25 s. Continuous positive airway pressure and administration of medroxyprogesterone acetate prevented further episodes and relieved much of the somnolence and lethargy that had contributed to the evidence for myxedema. Alveolar hypoventilation caused by decreased sensitivity to carbon dioxide, inadequate central neural drive, peripheral muscle force, and obesity all may have contributed to the apnea. Chest pain has not recurred, and results of electrocardiography have remained normal following full thyroid hormone replacement. The early recognition of myxedema causing sleep apnea will allow specific treatment to avoid the cardiovascular risks related to prolonged apnea and will help avoid confusion with other etiologies of cardiovascular abnormalities.     

Differential binding of P. aeruginosa and S. aureus to corneal epithelium in culture

Adherence of bacteria to corneal epithelium is a prerequisite for corneal infection. We used two methods to study the binding of Pseudomonas aeruginosa and Staphylococcus aureus to rabbit corneal epithelial cells in culture. In the first method, rabbit corneal epithelial cells grown on glass slides were incubated with P. aeruginosa or S. aureus (10(7) CFU/ml) at room temperature for 90 min, and the bacterial binding to the epithelial cells was examined by light microscopy. Both P. aeruginosa and S. aureus bound to epithelial cells. P. aeruginosa was bound to the cell periphery whereas S. aureus was bound randomly to the cell surface. In the second method, suspension cultures of corneal epithelial cells were used. In contrast to the findings in cultures on slides, binding pattern with cells in suspension was similar for both species and resembled that for S. aureus in cultures on slides. A much greater number of P. aeruginosa (186 +/- 11 bacteria/epithelial cell) than S. aureus (30 +/- 1.5 bacteria/epithelial cell) bound to epithelial cells grown on glass slides. In contrast, a similar number of P. aeruginosa (25 +/- 5.1) and S. aureus (20 +/- 4.7) bound to epithelial cells grown in suspension cultures. Using either method, Escherichia coli and Streptococcus pyogenes did not bind significantly (less than 5/cell) to corneal epithelial cells. The above methods should prove useful for characterization of bacterial binding to corneal epithelial cells in culture.     

Rehabilitation of the patient with chronic back pain. A search for outcome predictors

This prospective study was initiated 3 years ago to evaluate the outcome and to identify predictors of success or failure in patients admitted to a rehabilitation program for chronic low-back pain. Multiple parameters were evaluated, including psychologic data (MMPI, personal interview, pain drawing, etc.), physical measurements (flexibility, strength and endurance), and demographic data concerning the patient's home and working environment. Information was available on each patient admitted to the program prior to his admission, at completion of the program, 6 weeks following completion of the program and 3 months following completion of the program. A telephone interview was carried out 2 1/2 years following the patient's discharge from the program. Linear regression analysis was used to identify the important independent variables with regard to the dependent variables of relief of back pain, return to work and increased activities at home. Demographic data were of no value as a predictor with the exception of age and returning to work. The patients over the age of 50 returned to work with much less frequency than those less than 50. Psychologic information from the MMPI and similar tests were of no value. The personal preadmission interview of a trained psychologist, however, was a good predictor of an individual's eventual return to work and overall improvement. Worker's Compensation and other litigation was a negative factor in a patient's prognosis. The treatment team's prognosis at the time of discharge from the program was the best overall predictor of a patient's chance of success or failure in the longterm.     

Progesterone potentiation of bupivacaine arrhythmogenicity in pentobarbital-anesthetized rats and beating rat heart cell cultures.

The effects of progesterone treatment on bupivacaine arrhythmogenicity in beating rat heart myocyte cultures and on anesthetized rats were determined. After determining the bupivacaine AD50 (the concentration of bupivacaine that caused 50% of all beating rat heart myocyte cultures to become arrhythmic), we determined the effect of 1-hour progesterone HCl exposure on myocyte contractile rhythm. Each concentration of progesterone (6.25, 12.5, 25, and 50 micrograms/ml) caused a significant and concentration-dependent reduction in the AD50 for bupivacaine. Estradiol treatment also increased the arrhythmogenicity of bupivacaine in myocyte cultures, but was only one fourth as potent as progesterone. Neither progesterone nor estradiol effects on bupivacaine arrhythmogenicity were potentiated by epinephrine. Chronic progesterone pretreatment (5 mg/kg/day for 21 days) caused a significant increase in bupivacaine arrhythmogenicity in intact pentobarbital-anesthetized rats. There was a significant decrease in the time to onset of arrhythmia as compared with control nonprogesterone-treated rats (6.2 +/- 1.3 vs. 30.8 +/- 2.5 min, mean +/- SE). The results of this study indicate that progesterone can potentiate bupivacaine arrhythmogenicity both in vivo and in vitro. Potentiation of bupivacaine arrhythmia in myocyte cultures suggests that this effect is at least partly mediated at the myocyte level.     

Certification: serving the public interest

The certification program has undergone an exciting change. The AOTA leadership and AOTA members are to be applauded for making this important step. The AOTCB is still a fledgling organization; nonetheless, it has already made great strides in carrying out its mission. The AOTCB will continue to build on the very excellent foundation AOTA has laid for the certification program. The AOTCB welcomes questions, comments, and suggestions concerning the certification program. To contact AOTCB, write to AOTCB, 1383 Piccard Drive, Rockville, MD 20850-4375 or call (301) 948-9626.