A randomised controlled trial of 7.5-mm and 7.0-mm tracheal tubes vs. 6.5-mm and 6.0-mm tracheal tubes for men and women during laparoscopic surgery.

Sore throat after tracheal intubation impairs postoperative recovery. We randomly allocated 172 ASA physical status 1-2 participants, scheduled for laparoscopic lower abdominal surgery, to tracheal intubation with larger tubes (n = 88) or smaller tubes (n = 84), with internal diameters 7.5-mm vs. 6.5-mm for men and 7.0-mm vs. 6.0-mm for women. Primary outcome was the rates of no, mild, moderate or severe sore throat 1 h after surgery, which were 60, 10, 17 and 1 with larger tracheal tubes and 79, 5, 0 and 0 with smaller tubes, p < 0.001. The equivalent rates 24 h after surgery were 64, 16, 8 and 0 vs. 74, 6, 3 and 1, p = 0.037. Intra-operative ventilatory variables were unaffected by tube diameter, including peak inspiratory pressure, plateau pressure and end-tidal carbon dioxide partial pressure. In summary, smaller tracheal tubes benefitted patients having laparoscopic operations.

Cryptopain-1, a cysteine protease of Cryptosporidium parvum, does not require the pro-domain for folding.

SUMMARY: Cryptosporidium parvum is an intracellular protozoan parasite that causes cryptosporidiosis in mammals including humans. In the current study, the gene encoding the cysteine protease of C. parvum (cryptopain-1) was identified and the biochemical properties of the recombinant enzyme were characterized. Cryptopain-1 shared common structural properties with cathepsin L-like papain family enzymes, but lacked a typical signal peptide sequence and contained a possible transmembrane domain near the amino terminus and a unique insert in the front of the mature domain. The recombinant cryptopain-1 expressed in Escherichia coli and refolded to the active form showed typical biochemical properties of cathepsin L-like enzymes. The folding determinant of cryptopain-1 was characterized through multiple constructs with or without different lengths of the pro-domain of the enzyme expressed in E. coli and assessment of their refolding abilities. All constructs, except one that did not contain the full-length mature domain, successfully refolded into the active enzymes, suggesting that cryptopain-1 did not require the pro-domain for folding. Western blot analysis showed that cryptopain-1 was expressed in the sporozoites and the enzyme preferentially degraded proteins, including collagen and fibronectin, but not globular proteins. This suggested a probable role for cryptopain-1 in host cell invasion and/or egression by the parasite.