Planned postradiotherapy bilateral neck dissection for head and neck cancer.

PURPOSE: This is a retrospective analysis of 50 patients with squamous cell carcinoma of the head and neck treated with radiotherapy (RT) to the primary site and bilateral neck followed by a planned bilateral neck dissection approximately 4 to 6 weeks after completion of RT. PATIENTS AND METHODS: Between November 1964 and March 1997, 50 patients underwent bilateral neck dissections after RT, with minimum 2-year follow-up. Forty-eight patients had bilateral positive neck nodes. RESULTS: At 5 years, the rates of neck disease control, local-regional control, and cause-specific survival were 76%, 70%, and 39%, respectively. Five severe complications developed after surgery, and 1 developed after RT. CONCLUSIONS: Radiotherapy followed by a planned bilateral neck dissection resulted in a high rate of local-regional control with acceptable morbidity. The likelihood of severe complications after simultaneous (as opposed to staged) neck dissection was not significantly different (P =.24).

Dynamic modulation of the regulatory domain of myosin heads by pH, ionic strength, and RLC phosphorylation in synthetic myosin filaments.

The position of the myosin head with respect to the filament backbone is thought to be a function of pH, ionic strength (micro) and the extent of regulatory light chain (RLC) phosphorylation [Harrington (1979) Proc. Natl. Acad. Sci. U.S.A. 76, 5066-5070]. The object of this study is to examine the dynamics of the proximal part of the myosin head (regulatory domain) which accompany the changes in head disposition. The essential light chain was labeled at Cys177 with the indanedione spin-label followed by the exchange of the labeled proteins into myosin. The mobility of the labeled domain was investigated with saturation transfer electron paramagnetic resonance in reconstituted, synthetic myosin filaments. We have found that the release of the heads from the myosin filament surface by reduction of electrostatic charge is accompanied by a 2-fold increase in the mobility of the regulatory domain. Phosphorylation of the RLC by myosin light chain kinase resulted in a smaller 1. 5-fold increase of motion, establishing that the head disordering observed by electron microscopy [Levine et al. (1996) Biophys. J. 71, 898-907] is due to increased mobility of the heads. This result indirectly supports the hypothesis that the RLC phosphorylation effect on potentiation of force arises from a release of heads from the filament surface and a shift of the heads toward actin.

Wrist joint motion simulator.

A computer controlled wrist joint motion simulator has been developed that actively moves forearms from cadavers through cyclic planar flexion-extension motions, planar radial-ulnar deviation motions, and combined motions such as circumduction. Hybrid position-force feedback control algorithms are used to determine the wrist flexor and extensor tendon forces necessary to achieve the desired motions. The simulator was used in a series of 12 fresh cadaver forearms to produce both flexion-extension and radial-ulnar deviation motions and was found to cause repeatable, physiological movements. In these experiments, the extensor tendon forces were greater than those of the flexors, typically by a factor of two.

Measurements of fentanyl and sufentanil in blood and urine after surgical application. Implication in detection of abuse.

An increase in cases of death from overdose and abuse from fentanyl or sufentanil is being encountered by the Bexar County Forensic Science Center in San Antonio, Texas. These drugs have been abused almost solely by health care professionals. The fentanyl derivatives cannot currently be detected by routine laboratory drug-screening programs. Forensic toxicology assays that identify the specific analyte must be used. We report a sensitive assay for detection of fentanyl and sufentanil with a detection limit of -0.5 ng/ml. In addition, results from the analysis of urine and blood samples obtained up to 72 h after drug administration to five patients undergoing cardiac bypass surgery who had received either fentanyl or sufentanil are described. The new procedure enables detection of these drugs more readily, in smaller amounts, and for a longer period of time after use than previously possible. We hope this will lead to intervention and treatment in those abusing the drugs.

Eye injuries with metal missiles presenting to an emergency center: a three year study.

The authors retrospectively evaluated 33 eye injuries due to metal missiles in 31 patients presenting to our emergency center over the last 3 years. Injuries occurred most frequently when the patients were grinding metal or working on their cars. The type of metal involved in the injury often dictates the type of ophthalmic reaction that will occur. A discussion of intraocular metallic foreign bodies with an emphasis on electroretinograms and metal analysis is presented.

Telemetry instrumentation for kinesiologic studies of knee motion.

A low-cost FM/FM radio telemetry system is detailed, designed for motion analysis of the knee joint during walking in total knee replacement patients.