SH-It happens: S-H bonds as intrinsic 2D-IR labels in proteins.

Cysteine S-H bonds have a spectroscopically convenient stretching frequency of ∼2550 cm-1. However, their cross section is low, and the band can be strongly broadened in heterogeneous environments, making detection very challenging. With two-dimensional infrared (2D-IR) setups achieving ever higher sensitivities in recent years, systematic use of the weak cysteine sulfhydryls (Cys-SHs) absorption band is now within reach, even at low millimolar protein concentrations. Here, we demonstrate the capabilities of Cys-SH as an intrinsic 2D-IR label in pyruvate oxidase from E. coli, an enzyme with ten cysteines in its native sequence. 1D-IR measurements on the wild-type and individual cysteine knock-out variants show that two such residues have especially narrow SH signatures, caused by their intrahelical hydrogen bonding. 2D-IR analysis of these bands reveals an extraordinarily high anharmonicity (∼110 cm-1) and a long vibrational lifetime (∼4 ps). This allows monitoring spectral diffusion via center line slope analysis for up to 10 ps-separately for both the ground and excited states. The unique spectroscopic features and its ease of introduction make Cys-SH a useful IR spectroscopic label.

Evaluation of coverall field dry aerosol decontamination methods using a manikin.

A full-size manikin dressed in fire-resistant coveralls coated in 120 g of sodium bicarbonate was randomly given one of three treatments for dry aerosol decontamination. The three treatments were high-efficiency particulate air (HEPA) vacuum, a commercially available air shower, and the no treatment control. Immediately after the treatment, the coveralls were doffed and an air sample was taken in the breathing zone of the manikin to estimate airborne total and respirable dust concentrations to an unprotected worker post decontamination. Each treatment was applied four times for a total of 12 trials. Using analysis of variance (ANOVA) with alpha =.05 and Tukey's Honestly Significant Difference multiple comparison post-test, it was determined that HEPA vacuuming was not significantly different from the air shower for respirable dust, but only the air shower was significantly better than no decontamination (p =.037). For total dust, HEPA was not significantly different from the air shower, but both were significantly better than no treatment (p =.007, p =.004, respectively).

[Postoperative intensive care after thymectomy for myasthenia gravis]. / La réanimation post-opératoire après thymectomie pour myasthénie.

The post-operative management of the myasthenic patient after thymectomy through sternotomy has changed in the last decades. After years of routine preoperative tracheostomies followed by routine prolonged intubation nowadays it is possible to wean the patients from the ventilation and to extubate them early after surgery while reintroducing the acetylcholinesterase inhibitors therapy. A series of 15 patients operated on between 1985 and 1988 for removal of thymic rests or thymoma is presented and confirms this evolution. The clinical and gazometric criteria allowing an early weaning from the ventilator are analyzed. However certain patients with the most severe forms of myasthenic still need prolonged ventilatory support.