The Value and Potential of Qualitative Research Methods in Neurosurgery.

OBJECTIVE: To explore the value and potential of qualitative research to neurosurgery and provide insight and understanding to this underused methodology. METHODS: The definition of qualitative research is critically discussed and the heterogeneity within this field of inquiry explored. The value of qualitative research to the field of neurosurgery is articulated through its contribution to understanding complex clinical problems. DISCUSSION: To resolve some of the misunderstanding of qualitative research, this paper discusses research design choices. We explore approaches that use qualitative techniques but are not, necessarily, situated within a qualitative paradigm in addition to how qualitative research philosophy aids researchers to conduct interpretive inquiry that can reveal more than simply what was said by participants. Common research designs associated with qualitative inquiry are introduced, and how complex analysis may contribute more in-depth insights is explained. Approaches to quality are discussed briefly to support improvements in qualitative methods and qualitative manuscripts. Finally, we consider the future of qualitative research in neurosurgery, and suggest how to move forward in the qualitative neurosurgical evidence base. CONCLUSIONS: There is enormous potential for qualitative research to contribute to the advancement of person-centered care within neurosurgery. There are signs that more qualitative research is being conducted and that neurosurgical journals are increasingly open to this methodology. While studies that do not engage fully within the qualitative paradigm can make important contributions to the evidence base, due regard should be given to immersive inquiry within qualitative paradigms to allow complex, in-depth, investigations of the human experience.

A Candida albicans surface antigen mediating adhesion and autoaggregation in Saccharomyces cerevisiae.

In a previous study (M. Barki, Y. Koltin, M. Yanko, A. Tamarkin, and M. Rosenberg, J. Bacteriol. 175:5683-5689, 1993), a 3.3-kb DNA fragment from Candida albicans which confers adhesion and autoaggregation in Saccharomyces cerevisiae was isolated and partially characterized. In this report, evidence is presented that the adhesion-autoaggregation phenotype observed in S. cerevisiae cells transformed with the candidal DNA fragment is due to expression of a C. albicans surface antigen. Rabbit antiserum, prepared against transformant S. cerevisiae cells, was adsorbed with S. cerevisiae bearing the vector alone. Immunofluorescence micrography showed that the adsorbed antiserum bound to the surface of transformant S. cerevisiae cells as well as to C.albicans cells, but only marginally to the S. cerevisiae control. The absorbed antiserum specifically inhibited autoaggregation of transformant cells. Further adsorption of the antiserum with transformant cells eliminated both inhibition and immunofluorescence. Autoaggregative activity and immunofluorescence of transformant cells were abolished following proteolytic treatment. Western blot (immunoblot) analysis of candidal extracts revealed that the absorbed antiserum recognized a major candidal antigen of ca. 30 kDa which was present on both yeast-phase and germ tube cells. The data suggest that the observed adhesion-autoaggregation phenotype is due to the presence of a specific candidal antigen on the outer surface of the transformant cells.

Isolation of a Candida albicans DNA sequence conferring adhesion and aggregation on Saccharomyces cerevisiae.

Candida albicans is an opportunistic pathogen which may give rise to superficial and systemic infections. In the present study, C. albicans adhesion was studied by expression of C. albicans DNA sequences encoding adhesion functions in a nonadherent strain of Saccharomyces cerevisiae. Adherent transformant cells of S. cerevisiae harbouring a C. albicans genomic library cloned in a yeast-Escherichia coli shuttle vector were selected by using tissue culture-treated polystyrene as the attachment substratum. One transformant exhibited enhanced adhesion to treated and untreated polystyrene as well as autoaggregation, unlike control cells bearing the vector alone. Analysis of this clone revealed an insert of ca. 4.5 kb from C. albicans. Curing of the plasmid resulted in loss of adhesion and autoaggregation properties. A subclone bearing a reduced insert of 3.3 kb retained the ability to autoaggregate, to bind to treated and untreated polystyrene, and to adhere to buccal epithelial cells, unlike appropriate controls. Further subcloning of the insert to 2.7- and 1.9-kb fragments resulted in incremental decreases in adhesion and autoaggregation, whereas smaller fragments did not confer these properties. Hybridization of the 2.7-kb segment with C. albicans and S. cerevisiae DNA confirmed its origin as a single-copy sequence in the C. albicans genome as well as the absence of a homologous sequence in the genome of S. cerevisiae. The data suggest that the adhesion and aggregation phenomena of the transformant cells are related to expression of a C. albicans surface antigen encoded by the cloned DNA fragment.

Initial testing of a novel urine culture device.

The Diaslide urine culture device consists of a hinged case containing two opposing agar media separated by a sampler with a handle at one end and two bent sampler tips at the opposite end. The tips of the sampler are first dipped into the urine. The sampler is then pulled out through the casing, simultaneously inoculating both agar surfaces with a streaking dilution. As a result, individual colonies can be observed even when bacterial concentrations exceed 10(6) CFU/ml. The number of colonies on the Diaslide correlated linearly with CFU per milliliter as determined by dilution plating. The clinical performance of the Diaslide was compared with those of ordinary dipslides and conventional cultures with a sample of 473 prescreened hospital urine specimens. The sensitivity, specificity, and positive predictive value of Diaslide versus those of culture at the 10(4)-CFU/ml cutoff level were 97.5, 98.3, and 98.3%, respectively, compared with 98.8, 95.7, and 97.2%, respectively, for dipslide versus culture. Similar results were found at the 10(5)-CFU/ml cutoff level. Only 5.5% of the Diaslides required subculturing, compared with 14.7 and 9.4% of the dipslides and conventional cultures, respectively. The Diaslide proved more convenient than an ordinary dipslide for sampling low volumes of urine. These data suggest that the Diaslide is a simple, effective device for culturing of urine specimens.

Day-long reduction of oral malodor by a two-phase oil:water mouthrinse as compared to chlorhexidine and placebo rinses.

Few scientific investigations have addressed the ability of mouthrinses to reduce oral malodor for periods longer than 3 hours. In the present report, we have employed simple, recently described techniques to assess the day-long reduction in oral malodor of a novel 2-phase oil:water mouthrinse (TPM), as compared to a corresponding placebo rinse, and to a commercial 0.2% chlorhexidine mouthrinse. Sixty dental students were divided randomly into 3 groups, and instructed to use one of the rinses prior to bedtime and the following morning. Measurements carried out in the late afternoon, about 8 to 10 hours following rinsing, were compared with baseline measurements carried out in the late afternoon of the previous day. Volatile sulphide levels were measured using a portable industrial sulphide monitor. Microbial levels were estimated using a simple rinsing technique employing sterilized milk. These quantitative techniques were corroborated by organoleptic (hedonic) ratings of a single odor judge. Both TPM and chlorhexidine brought about significant decreases in volatile sulphides (P less than 0.05) as compared to the placebo group. These results were corroborated by the organoleptic data. Similarly, both chlorhexidine and TPM were highly effective in reducing microbial levels as measured by the rinsing technique, in comparison to the placebo group. Chlorhexidine appeared to be more effective than TPM in all measurement categories, although only in the case of microbial activity was there a significant (P less than 0.05) difference between the two groups.

[Influence of chronic smoking on leukocytes]. / Influence du tabagisme chronic sur les leucocytes.

The authors showed a significant increase in total leukocyte count (2p less than 0.001), neutrophil concentration (2p less than 0.001) and lymphocyte concentration (2p less than 0.01) in 21 chronic smokers compared to 22 non-smokers. However, only the total leukocyte count and the neutrophil count proved to be correlated to carboxyhemoglobin saturation. Slightly different hypotheses are proposed to explain the increase in leukocyte count: the carbon monoxide and/or the carboxyhemoglobin acts directly on peripheral blood leukocytes or indirectly, via the adrenalin secretion. The average leukocyte count in smokers corresponds to the upper borderline in nonsmokers; therefore, it seems pertinent to take into consideration the number of cigarettes smoked per day when assessing a smoker's leukocytosis.