Traumatic esophageal rupture: unusual cause of acute mediastinal widening

We have presented the case of a 32-year-old man who sustained blunt trauma to the chest in a motor vehicle accident. Plain roentgenograms showed a widened mediastinum and pneumomediastinum, and an esophagogram with water-soluble contrast material showed an esophageal laceration at the T-4 level.     

Office-based laryngeal laser surgery: a review of 443 cases using three wavelengths.

BACKGROUND: Unsedated office-based laser surgery (UOLS) of the larynx and trachea has significantly improved the treatment options for patients with laryngotracheal pathology including recurrent respiratory papillomas, granulomas, leukoplakia, and polypoid degeneration. UOLS delivered by flexible endoscopes has dramatically impacted office-based surgery by reducing the time, costs, and morbidity of surgery. OBJECTIVES: To review our experience with 443 laryngotracheal cases treated by UOLS. METHODS: The laser logbooks at the Center for Voice and Swallowing Disorders were reviewed for UOLS, and the medical and laryngological histories were detailed, as were the treatment modalities, frequencies, and complications. RESULTS: Of the 443 cases, 406 were performed with the pulsed-dye laser, 10 with the carbon-dioxide laser, and 27 with the thulium: yttrium-aluminum-garnet laser. There were no significant complications in this series. A review of indications and wavelength selection criteria is presented. CONCLUSION: Unsedated, office-based, upper aerodigestive tract laser surgery appears to be a safe and effective treatment option for many patients with laryngotracheal pathology.     

TNO-6 has no effect in gastrointestinal cancer: N-acetyl-glucosaminidase shows renal damage

Twenty-five patients, 16 with gastric cancer and nine with colonic cancer, received TNO-6 30 mg m-2 every four weeks. No objective tumour response was recorded. Nausea and vomiting occurred in 21 patients and was severe in 17. Severe marrow suppression developed in five patients. Renal function was unaffected in all but one patient who developed renal failure, probably as a result of septicaemia. However, the renal tubular enzyme N-acetyl-beta-D-glucosaminidase was measured in six patients and showed a rise in all. In this study TNO-6 had no anti-tumour activity in gastrointestinal malignancy, but produced significant renal tubular damage.     

Relative effect of surgery and radiotherapy on the internal jugular vein following functional neck dissection

We examined the internal jugular veins in three groups of patients who had undergone (1) a functional neck dissection and radiotherapy, (2) a functional neck dissection alone, or (3) radiotherapy alone, using a noninvasive color Doppler ultrasound scan. The internal jugular veins were ultrasonically bilaterally normal in 18% of patients who had undergone a functional neck dissection and radiotherapy, in 88% of patients who had undergone a functional neck dissection alone, and in 57% of patients who had undergone radiotherapy alone. The combination of a functional neck dissection and radiotherapy significantly affected the internal jugular vein when compared with a functional neck dissection alone.     

Conformational preference for the binding of biaryl substrates and inhibitors to the active site of phenylethanolamine N-methyltransferase

We have previously described regions of steric bulk tolerance in the aromatic-ring binding site of phenylethanolamine N-methyltransferase (PNMT, EC 2.1.1.28) for phenylethanolamine substrates and alpha-methylbenzylamine inhibitors. For bound substrates, this region is located in the vicinity of the para position of the aromatic ring, while for bound alpha-methylbenzylamine inhibitors, it is located in the region complementary to the meta position. In the present study, we sought to determine the preferred conformation of the biaryl portion of (m-phenylphenyl)- and (p-phenylphenyl)ethanolamine (4 and 5, respectively) as well as for m-phenyl- and p-phenyl-alpha-methylbenzylamine (7 and 8, respectively) for PNMT active site interactions. Planar derivatives of 4, 5, 7, and 8 were obtained through the synthesis of 2-(1-fluorenyl)-2-hydroxyethylamine (9), 2-(2-fluorenyl)-2-hydroxyethylamine (10), 1-(1-fluorenyl)ethylamine (11), and 1-(2-fluorenyl)ethylamine (12). The four fluorene derivatives were examined for in vitro activity as substrates and inhibitors of the PNMT-catalyzed reaction. As in the case of 4, 5, 7, and 8, we have observed a positional preference for the alkylamine side chain with respect to the biphenyl skeleton present in 9-12. Thus, fluorenylethanolamine 10 ("p-biphenyl") displays a Michaelis constant (Km = 26 microM) that is approximately 10 times lower than that for 9 ("m-biphenyl", Km = 297 microM); in the alpha-methylbenzylamine inhibitors, fluorenyl derivative 11 ("m-biphenyl", Ki = 4.14 microM) is approximately 40 times better than 12 ("p-biphenyl", Ki = 185 microM) for in vitro inhibition of PNMT. In each case, conformational restriction of the biaryl system present in 4, 5, 7, and 8, such that the aromatic rings are coplanar, resulted in enhanced affinity for the PNMT active site. Thus, conformational restriction of ethanolamine 5 (Km = 82 microM) as in 10 (Km = 26 microM) and alpha-methylbenzylamine 7 (Ki = 89 microM) as in 11 (Ki = 4.14 microM) leads, in each case, to a stronger enzyme-ligand dissociable complex. These results, in conjunction with others from these laboratories, indicate that the PNMT active site beyond the zone that interacts with the central aromatic ring portion of phenylethanolamine substrates and alpha-methylbenzylamine inhibitors is essentially a flat, hydrophobic pocket.     

Amount and distribution of dietary protein affects clinical response to levodopa in Parkinson's disease

Reducing dietary protein improves the effectiveness of levodopa (LD) but the most effective distribution of a low-protein diet (0.8 g/kg) is unclear. We compared a 1.6 g/kg protein diet, a 0.8 g/kg diet with protein evenly distributed between meals, and a 0.8 g/kg diet with protein restricted to the evening meal in 5 parkinsonian patients with motor fluctuations. We monitored clinical response, plasma LD, and plasma large amino acids (LNAAs) hourly throughout the day. Mean "on" times were 51% (1.6 g/kg diet), 67% (0.8 g/kg evenly distributed), and 77% (0.8 g/kg restricted). Hourly averages of plasma LD did not differ between the diets. The mean plasma LNAAs were 732 nmol/ml (1.6 g/kg diet), 640 (0.8 g/kg distributed), and 542 (0.8 g/kg restricted), and the diurnal pattern reflected the distribution of protein intake. In conclusion, the amount and distribution of dietary protein affect clinical response to LD. These effects are not related to LD absorption but are explained by the variation in plasma LNAAs.