A multiple-capillary electrophoresis system for small-scale DNA sequencing and analysis.
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A five-capillary system has been developed for DNA sequencing and analysis. The post-column fluorescence detector is based on a sheath-flow cuvette. The instrument provides uniform and continuous illumination of the samples. The cuvette virtually eliminates cross-talk in the fluorescence signal between capillaries. Discrete single-photon counting avalanche photodiodes provide high efficiency light detection. The instrument has detection limits (3sigma) of 130 +/- 30 fluorescein molecules injected onto each capillary. Over 650 bases of sequence at 98.8% accuracy were generated in 100 min at 50 degrees C from M13mp18. Separation and detection of short tandem repeats proved efficient and accurate with the use of internal standards for direct comparison of migration times between capillaries. (+info)
A new bronchoscopic method to measure airway size.
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Bronchoscopic evaluation of stenosis is limited due to radial distortion of bronchoscopic images and the unknown distance between the endoscope and the stenotic area. The purpose of this study was the development and validation of a method for measuring cross-sectional areas in large airways. Distance measurements were performed using a laser probe inserted into the working channel of a bronchoscope. The laser probe was positioned to the locus of interest in the airway, a ring of light (helium/neon) projected on to the luminal wall and the images acquired using an electronic bronchoscope. The images taken were distortion-corrected by means of a computer program. The method was validated by simulating airways using tubes of known diameter. Additionally, distortion-corrected bronchoscopic images were compared with distortion-free videoscopic image analysis of tracheal slices taken from pigs. In the case of the plastic tubes, Pearson's correlation coefficient (r) as well as the intraclass correlation coefficient (ICC) were slightly higher (r=0.99, p<0.01, ICC=0.97) than the correlation of cross-sectional areas between bronchoscopic and videoscopic images of tracheal slices (r=0.88, p<0.01, ICC=0.87). This concept allows accurate and reproducible determination of cross-sectional areas in large airways. (+info)
Incidence of bacteraemia following fibreoptic bronchoscopy.
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Guidelines for antibiotic prophylaxis of infective endocarditis prior to fibreoptic bronchoscopy, are based on only five studies, which showed a bacteraemia rate of <1% among 291 patients studied. T his study was designed to expand the current data regarding the frequency of bacteraemia following fibreoptic bronchoscopy. Aerobic and anaerobic cultures of venous blood and of lavage fluid were drawn from 200 consecutive patients undergoing fibreoptic bronchoscopy without respiratory infection or antibiotic treatment prior to the procedure. The true bacteraemia rate was calculated after excluding probable "contaminated" blood cultures. A possible correlation between type of procedure performed during the bronchoscopy and occurrence of bacteraemia was investigated. Positive blood cultures were noted following 26 bronchoscopy examinations. Coagulase negative Staphylococcus was found in the cultures of 18 patients, coagulase positive Staphylococcus in 3 patients, nonhaemolytic streptococci and a Klebsiella species in 2 patients each, and beta haemolytic streptococcus in one patient. After exclusion of 13 "contaminated" specimens the bacteraemia rate was 6.5% (13/200 patients). This study showed a bacteraemia rate of 6.5%, significantly higher than previously recognized in a cohort of patients undergoing fibreoptic bronchoscopy without either pulmonary infection or an unusually high rate of invasive procedures. These findings should be taken into account in future evaluations of recommendations for antibiotic prophylaxis of endocarditis. (+info)
Modulation of adhesion molecule profiles on alveolar macrophages and blood leukocytes.
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BACKGROUND: Cell adhesion molecules are believed to be essential for blood cell recruitment to the lung and for the movement of alveolar macrophages (AM) within the lung. OBJECTIVE: To investigate the expression pattern of L-selectin and beta(2) integrins on blood leukocytes and AM, including AM of various maturity. METHODS: Flow cytometry was used to study the expression of L-selectin (CD62L) and of the beta(2) integrins CD11a, CD11b, and CD11c on AM (including density-defined subpopulations), monocytes (Mo), polymorphonuclear neutrophils (PMN) and lymphocytes (Ly) sampled from healthy individuals, during incubation with and without lipopolysaccharide (LPS). RESULTS: A significantly different modulation pattern of beta(2) integrins and L-selectin was demonstrated on Mo and AM, cells of the same differentiation lineage. In contrast to AM, Mo had a marked ability to respond to LPS stimulation by increased expression of CD11a, CD11b and CD11c and decreased expression of L- selectin. These molecules were expressed to a similar degree on AM, whereas the basal levels of CD11b and L-selectin were considerably higher on Mo than on AM. A significantly different expression of CD11a as well as differences in the regulation of L-selectin during incubation were also demonstrated between density-defined subpopulations of AM. CD11a could not be upregulated on PMN, otherwise the modulation patterns of CD11b, CD11c and L-selectin were similar to that on Mo. The expression of CD11a on Ly was 3- to 6-fold higher than on Mo, PMN and AM. The level of CD11b decreased significantly upon incubation (uninfluenced by LPS stimulation), and CD11c was hardly expressed on Ly. The level of L-selectin on Ly was higher than on Mo, AM and PMN and was not decreased during incubation. CONCLUSION: Developmental origin, degree of cell differentiation (maturity) as well as different environmental conditions all heavily influence the expression and modulation pattern of beta(2) integrins and L-selectin on leukocytes and Mo-derived AM. (+info)
Concentrations of moxifloxacin in serum and pulmonary compartments following a single 400 mg oral dose in patients undergoing fibre-optic bronchoscopy.
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The concentrations of moxifloxacin achieved after a single 400 mg dose were measured in serum, epithelial lining fluid (ELF), alveolar macrophages (AM) and bronchial mucosa (BM). Concentrations were determined using a microbiological assay. Nineteen patients undergoing fibre-optic bronchoscopy were studied. Mean serum, ELF, AM and BM concentrations at 2.2, 12 and 24 h were as follows: 2.2 h: 3.2 mg/L, 20.7 mg/L, 56.7 mg/L, 5.4 mg/kg; 12 h: 1.1 mg/L, 5.9 mg/L, 54.1 mg/L, 2.0 mg/kg; 24 h: 0.5 mg/L, 3.6 mg/L, 35.9 mg/L, 1.1 mg/kg, respectively. These concentrations exceed the MIC(90)s for common respiratory pathogens such as Streptococcus pneumoniae (0.25 mg/L), Haemophilus influenzae (0.03 mg/L), Moraxella catarrhalis (0.12 mg/L), Chlamydia pneumoniae (0.12 mg/L) and Mycoplasma pneumoniae (0. 12 mg/L) and indicate that moxifloxacin should be effective in the treatment of community-acquired, lower respiratory tract infections. (+info)
Efficiency of a new fiberoptic stylet scope in tracheal intubation.
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BACKGROUND: Failed or difficult tracheal intubation is an important cause of morbidity and mortality during anesthesia. Although a number of fiberoptic devices are available to circumvent this problem, many do not allow manual control of the flexion of the tip and necessitate time-consuming preparation, special training, or the use of an external light source. To improve these limitations, the authors designed a new fiberoptic stylet scope (FSS) that has a simple form of a standard stylet with the fiberoptic view and maneuverability of its tip. This study was undertaken to prospectively evaluate the effectiveness of the FSS in tracheal intubation. METHODS: Thirty-two patients undergoing general surgery participated in this study. The authors used a standard laryngoscope only to elevate the tongue, then tracheal intubation was attempted with the glottic opening being viewed only through the FSS. The success rate, time necessary for intubation, hemodynamics, and adverse effects were recorded. RESULTS: The success rate of tracheal intubation on the first attempt using the FSS was 94% (30 of 32 patients), and the remaining two patients were intubated successfully on the second attempt. The mean time necessary for the intubation procedure was 29+/-14 s in all patients (mean +/- SD). Changes in hemodynamics during intubation were well within acceptable ranges. There were no major adverse effects, but minor sore throat (28%) and minor hoarseness (25%) on the first postoperative day. CONCLUSIONS: Tracheal intubation using the FSS proved to be a simple and effective technique for airway management. (+info)
Pharyngeal mucosal pressure and perfusion: a fiberoptic evaluation of the posterior pharynx in anesthetized adult patients with a modified cuffed oropharyngeal airway.
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BACKGROUND: Pharyngeal airway devices can exert substantial pressures against the pharyngeal mucosa. The authors assess the relation between pharyngeal mucosal perfusion and directly measured mucosal pressure (MP) in the posterior pharynx using a fiberoptic technique with a modified cuffed oropharyngeal airway (COPA). The authors also measure in vivo intracuff pressure (CP), airway sealing pressure and MP at four locations using an unmodified COPA. METHODS: Twenty adult patients, American Society of Anesthesiologists status I or II, undergoing general anesthesia were allocated randomly to receive either (1) a COPA with a millimeter microchip sensor fixed on the external cuff surface to record distal posterior pharyngeal MP or (2) a COPA with a fiberoptic scope inserted inside the cuff to record digitized images of the distal posterior pharyngeal mucosa. MP and digitized images were obtained at the same location over an in vivo CP range of 10-160 cm H2O in 10- to 20-cm H2O increments. The digitized images were scored according to blood vessel caliber and mucosal color by two investigators blinded to MP and CP. In an additional 20 matched patients, in vivo CP, airway sealing pressure, and MP was measured at four different cuff locations (corresponding to the anterior, lateral, and posterior pharynx and the distal oropharynx) with increasing cuff volume. RESULTS: Blood vessel caliber and mucosal color was normal in all patients when the mean mucosal pressure was 17 cm H2O. Blood vessel caliber was first reduced when the mean mucosal pressure was 34 cm H2O. There was a progressive incremental reduction in blood vessel caliber and mucosal color when the mean mucosal pressure increased from 34 to 80 cm H2O (P < or = 0.05). Complete blood vessel collapse and mucosal paling first occurred with the mean mucosal pressure was 73 cm H2O and was present in 90% of patients when the mean mucosal pressure was 80 cm H2O. Mean MP was always higher in the posterior pharynx compared with the other locations when the cuff volume was 20 ml or greater (P < 0.001). In vivo CP is an excellent predictor of mucosal pressure. Mean (95% confidence interval [CI]) MP in the posterior pharynx was 35 (5-67) and 78 (50-109) cm H2O when the airway sealing pressure was 10 (6-16) and 17 (13-21) cm H2O respectively. CONCLUSION: Pharyngeal mucosal perfusion is reduced progressively in the posterior pharynx when MP is increased from 34 to 80 cm H2O with the COPA. CP provides reliable information about MP and should be less than 120 cm H2O to prevent mucosal ischemia. (+info)
Preparing to perform an awake fiberoptic intubation.
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Fiberoptically guided tracheal intubation represents one of the most important advances in airway management to occur in the past thirty years. Perhaps its most important role is in management of the anticipated difficult airway. This is a situation in which the dangers of encountering the life-threatening "can't intubate, can't ventilate" situation can be avoided by placement of an endotracheal tube while the patient is awake. Although skill at the procedure of endoscopy is obviously necessary in this setting, these authors hold that success or failure of the technique frequently depends on the adequacy of preparation. These measures include 1) pre-operative assessment of the patient; 2) careful explanation of what lies in store; 3) "setting the stage"; 4) preparing the equipment to be used; and 5) preparing the patient (antisialogue, sedation, application of topical anesthesia to the upper airway). If these preparatory measures are carried out meticulously, the likelihood of performing a successful and comfortable awake fiberoptic tracheal intubation is greatly increased. (+info)