Impact of direct laryngoscopy vs. videolaryngoscopy on signal quality of recurrent laryngeal nerve monitoring in thyroid surgery: a randomised parallel group trial.

In thyroid surgery, intra-operative neuromonitoring signals of the recurrent laryngeal nerve can be detected by surface electrodes on a tracheal tube positioned at the vocal fold level. The incidence of difficult tracheal intubation in patients undergoing thyroidectomy for nodular goitre ranges from 5.3% to 20.5%. The aim of this study was to compare videolaryngoscopy with conventional direct laryngoscopy as methods for proper placement of the surface electrode to prevent insufficient intra-operative nerve signal quality. In this prospective randomised trial, adult patients requiring tracheal intubation during thyroid surgery were randomly allocated to two groups of C-MAC® (Macintosh style blade) videolaryngoscope or direct laryngoscopy using the Macintosh laryngoscope. Primary outcome was the incidence of insufficient signal electromyogram amplitude level (< 500 µV) after successful tracheal intubation. A total of 260 (130 per group) participants were analysed. An insufficient signal was more frequent with direct laryngoscopy (35/130, 27%), compared with C-MAC (12/130, 9%, p < 0.001). First-pass tracheal intubation success rate was lower with direct laryngoscopy (86/130 (66%)) compared with the C-MAC (125/130 (96%)) (p < 0.0001). Cormack and Lehane grade ≥ 3 was observed more frequently with direct laryngoscopy (16/130 (12%)), compared with the C-MAC (0/130, (0%)) (p < 0.0001). The results suggest that videolaryngoscopy has an impact on the quality of the initial intra-operative neuromonitoring signal in patients undergoing thyroid surgery, and this technique can provide optimised surface electrode positioning.

Molecular epidemiology of Candida albicans colonization and fungemia in very low birthweight infants.

OBJECTIVE: This study investigated the relationship between colonization and fungemia. DESIGN: This was a prospective study involving surveillance cultures of the nares, base of umbilicus, point of entry of umbilical catheter and parenteral fluids. Blood cultures were done when sepsis was suspected. All Candida albicans isolates were typed using restriction enzyme analysis of DNA. SETTING: Patients were from the neonatal intensive care unit of a tertiary care hospital. POPULATION STUDIED: Twenty-nine very low birthweight infants. MAIN RESULTS: Eleven babies were colonized with C albicans and five of these babies developed fungemia, including five of seven who were colonized at the point of entry of the umbilical catheter. Three different strains of C albicans caused fungemia. In four of the five patients, initial catheter entry site isolates were identical to the subsequent blood isolates. Occasionally, infants were colonized with more than one strain of C albicans. CONCLUSIONS: Preceding colonization with C albicans and, in particular, colonization at the site of entry of umbilical vascular catheters are risk factors for subsequent development of C albicans fungemia. Fungemic and colonizing isolates are usually identical to one another by DNA typing.

Chlamydia trachomatis elementary bodies possess proteins which bind to eucaryotic cell membranes.

Chlamydia trachomatis proteins were electrophoresed and then transferred to nitrocellulose paper to detect chlamydial proteins which bind to eucaryotic cell membranes. Resolved polypeptides of C. trachomatis serovars J and L2 were reacted with iodinated HeLa cell membranes and autoradiographed. Infectious elementary bodies of both serovars possess 31,000- and 18,000-dalton proteins which bind to HeLa cells. In contrast, noninfectious reticulate bodies do not possess eucaryotic cell-binding proteins. Both proteins are antigenic when reacted with hyperimmune rabbit antisera in immunoblots and antisera raised against the 31,000- and 18,000-dalton proteins are inhibitory to chlamydia-host cell association. In addition, these antisera exhibit neutralizing activity. Our data suggest that these putative chlamydial adhesins play a key role in the early steps of chlamydia-host cell interaction and that antibody directed against them may be protective.

Antigenic analysis of Giardia duodenalis strains isolated in Alberta.

Giardia duodenalis is a common intestinal parasite in most parts of the world. In Canada it is associated with both endemic and epidemic infections that are often transmitted by the waterborne route. Although G. duodenalis strains have been isolated from several animals, the role of other mammals in human infection is unclear. We have isolated and cultured G. duodenalis trophozoites from domestic and wild animals in Alberta and compared them with a human isolate by protein gel electrophoresis and immunoblot analysis. All strains examined share a similar polypeptide profile and important protein antigens. Prominent antigens of 62, 52, 38, and 31 kilodaltons are conserved. The 52- and 31-kilodalton proteins are the major surface-exposed trophozoite components. The high degree of antigenic sharing among strains from different hosts suggests that there may be a wide range of potential reservoirs for G. duodenalis infections.

Chlamydia trachomatis RNA polymerase alpha subunit: sequence and structural analysis.

We describe the cloning and sequence analysis of the region surrounding the gene for the alpha subunit of RNA polymerase from Chlamydia trachomatis. This region contains genes for proteins in the order SecY, S13, S11, alpha, and L17, which are equivalent to Escherichia coli and Bacillus subtilis r proteins. The incorporation of chlamydial alpha subunit protein into the E. coli RNA polymerase holoenzyme rather than its truncated variant lacking the amino terminus suggests the existence of structural conservation among alpha subunits from distantly related genera.

56K fibroblast protein not specific for Duchenne muscular dystrophy but for skin biopsy site.

Recently, we reported the detection by two-dimensional gel electrophoresis of a 56,000 (56K)-molecular weight polypeptide that was present in cultured skin fibroblasts from normal males but was not detectable in fibroblasts from Duchenne muscular dystrophy (DMD) patients. Since then we have established that the 56K polypeptide is not present in skin fibroblasts from normal females, DMD carrier females, or in normal male fibroblasts obtained from sources other than the Repository for Mutant Human Cell Strains, Montreal. Further inquiry has led to the discovery that all the normal male fibroblast cultures obtained from the Montreal repository had been established from preputial skin. Fibroblast cultures from DMD patients, DMD carriers, as well as other normal individuals, had been derived from non-genital skin biopsies. Thus, the absence of the 56K polypeptide is not specific for DMD, but rather is related to the site of skin biopsy.

Characterization of an immunodominant Giardia lamblia protein antigen related to alpha giardin.

The trophozoites of Giardia lamblia possess several protein antigens, predominant among them a protein of approximately 32,000 Da. In the present study, we used monospecific antibodies that recognize this protein to demonstrate its presence on a variety of G. lamblia isolates from human and animal sources. Immune electron microscopy was used to localize 32-kDa antigen on the trophozoite membrane and disk. Immunofluorescent assays employing monospecific antibodies confirmed the presence of 32-kDa antigen on the membrane and disk and its absence on flagella or nuclei. The N-terminal 17 amino acids of the 32-kDa antigen are identical to alpha-1-giardin, a protein component of microribbons on the ventral disk. These results suggest that the 32-kDa immunodominant trophozoite antigen is alpha-1-giardin.