Effect of ozone exposure on allergic sensitization and airway inflammation induced by dendritic cells

BACKGROUND: Epidemiological studies suggest that ozone exposure is related to increased asthma symptoms. Dendritic cells (DCs) are the principal antigen-presenting cells in the airways. OBJECTIVE: We have examined whether ambient doses of ozone (100 ppb for 2 h) enhance allergic sensitization and/or airway inflammation in a mouse model. METHODS: C57BL/6 mice were sensitized to inhaled ovalbumin (OVA) by intratracheal instillation of OVA-pulsed DCs on day 0. Daily exposure to OVA aerosol on days 14-20 resulted in an eosinophilic airway inflammation, as reflected in bronchoalveolar lavage fluid and lung histology. In a first experiment, mice were exposed to ozone or room air immediately prior to and following sensitization. Subsequently, we tested the effect of ozone exposure during antigen challenge in DC-sensitized mice. RESULTS: Exposure to ozone during sensitization did not influence airway inflammation after subsequent allergen challenge. In contrast, in sensitized mice, challenge with OVA together with ozone (days 14-20) resulted in enhanced airway eosinophilia and lymphocytosis, as compared with mice exposed to OVA and room air (1.91 x 106 +/- 0.46 x 106 vs. 0.16 x 106 +/- 0.06 x 106 eosinophils/mL lavage fluid; P = 0.015; 0.49 x 106 +/- 0.11 x 106 vs. 0.08 x 106 +/- 0.03 x 106 lymphocytes/mL lavage fluid; P = 0.004). Ozone exposure without subsequent OVA exposure did not cause airway inflammation. CONCLUSION: Ozone exposure does not increase allergic sensitization but enhances antigen-induced airway inflammation in mice that are sensitized via the airways.     

Influence of matching for exposure time on estimates of attributable mortality caused by nosocomial bacteremia in critically ill patients.

OBJECTIVE: To evaluate the influence of matching on exposure time on estimates of attributable mortality of nosocomial bacteremia as assessed by matched cohort studies. DESIGN: Two retrospective, pairwise-matched (1:2) cohort studies. SETTING: A 54-bed intensive care unit (ICU) in a university hospital. PATIENTS: Patients with nosocomial Escherichia coli bacteremia (n = 68) and control-patients without nosocomial bacteremia (n = 136 for each matched cohort study). INTERVENTION: In both matched cohort studies, the same set of bacteremic patients was matched with control-patients using the APACHE II system. In the first study, control-patients were required to have an ICU stay at least as long as the respective bacteremic patient prior to onset of bacteremia (matching on exposure time). In the second study, control-patients were required to have an ICU stay shorter than the stay prior to the development of bacteremia in the respective bacteremic patient (no matching on exposure time). RESULTS: For bacteremic patients, the mean ICU stay before onset of the bacteremia was 9 days (median, 6 days). In the first matched cohort study, hospital mortality was not different between bacteremic patients and control-patients (44.1% vs 43.4%; P = .999). In the second study, mortality of bacteremic patients and control-patients was also not different (44.1% vs 47.8%; P = .657). Mortality rates between control groups were not different (43.4% vs 47.8%; P = .543). CONCLUSION: Matching or not matching on exposure time did not alter the estimate of attributable mortality for ICU patients with E. coli bacteremia.     

Thyromental distance measurement – fingers don't rule

Thyromental distance (TMD) measurement is commonly used to predict difficult intubation. We surveyed anaesthetists to determine how this test was being performed. Comparative accuracy of ruler measurement and other forms of measurement were also assessed in a meta-analysis of published literature. Of respondents, 72% used fingers for TMD measurement and also considered three finger widths the minimum acceptable TMD. In terms of distance, the minimum acceptable TMD was felt to be 6.5 cm by 55% of respondents. However, the actual width of three fingers was (range) 4.6–7.0 cm (mean 5.9 cm), with significant differences between genders and between proximal and distal interphalangeal joints. The meta-analysis showed ruler measurement increased test sensitivity (48% (95% CI 43–53) vs 16% (95% CI 14–19) without a ruler), when predicting difficult intubation.     

Impact of recent intravenous chemotherapy on outcome in severe sepsis and septic shock patients with hematological malignancies

Objective To compare the characteristics and outcome of patients with hematological malignancies referred to the ICU with severe sepsis and septic shock who had or had not received recent intravenous chemotherapy, defined as within 3 weeks prior to ICU admission. Design and setting Retrospective observational cohort study on prospectively collected data in a medical ICU of a university hospital. Patients 186 ICU patients with hematological malignancies with severe sepsis or septic shock (2000–2006). Measurements and results There were 77 patients admitted with severe sepsis and 109 with septic shock; 91 (49%) had received recent intravenous chemotherapy. Patients with recent chemotherapy more often had a high-grade malignancy and were more often neutropenic, less often had pulmonary infiltrates, and less often required mechanical ventilation. ICU, 28-day, in-hospital, and 6-month mortality rates were 33% vs. 48.4%, 40.7% vs. 57.4%, 45.1% vs. 58.9%, and 50.5% vs. 63.2% in patients with and without recent chemotherapy, respectively. Logistic regression identified four variables independently associated with 28-day mortality: SOFA score at ICU admission, pulmonary site of infection, and fungal infection were associated with worse outcome whereas previous intravenous chemotherapy was protective at borderline significance. After adjustment with a propensity score for recent chemotherapy, chemotherapy was not associated with outcome. Conclusions Patients referred to the ICU with severe sepsis and septic shock complicating active chemotherapeutic treatment have better prognosis than commonly perceived. This article is discussed in the editorial available at: .     

The effect of polarized light on wound healing

. Recent investigations have reported contradictory results on the influence of low-power lasers and polarized light on wound healing. Different biologic effects have been observed after light irradiation but the real benefits of phototherapy in the healing of wounds in patients are still controversial. This article reports on a randomized, prospective single blind study that was set up to evaluate the effect of polarized light (wave length 400–2000 nm, degree of polarization >95%, power density 40 mW/cm², light energy 2.4 J/cm²) on the healing of standardized wounds. Twenty pairs of identical donor areas of split thickness skin grafts, taken on a similar location on each of the 20 patients, were treated according to an identical wound care protocol. The only difference was that one side was treated with polarized light and the other side without. The healing of these paired wounds was evaluated in a standardized manner and on a daily basis by two independent and blinded observers. The parameters assessed were: the degree of epithelialization, the quality of the granulation tissue, the degree of inflammation, the degree of infection, the aspect of the early scar tissue, blister formation, and the subjective feeling of the patient. Every parameter was scored on a 1–5 scale, with score 1 for the worst and score 5 for the best outcome. Long-term follow-up was performed after 1 month, 3 months, 6 months and 1 year. For all variables, except for infection and blister formation which was not seen in either group, highly significantly better scores were obtained in the donor sites treated with polarized light. Inter-observer agreement was acceptable to very good in all outcome variables. The results of this study demonstrated that polarized light had a beneficial effect on the healing of these standardized wounds, resulting in a faster epithelialization and an improved quality of early scar tissue formation.     

Quantitative evaluation of a beam-matching procedure using one-dimensional gamma analysis

This article provides a quantitative evaluation of Varian Medical Systems' beam matching procedure. A one-dimensional y analysis is employed to investigate the level of agreement of matched beams. A customized concept of one-dimensional gamma evaluation was designed. Our algorithm first performs a "local" fit of the reference and the evaluated datasets. For a particular point on the fitted evaluated curve, the y is derived as the shortest distance between the point and the fitted reference curve. This approach removes variations of the obtained y value related to the discrete character and noise in the original datasets. Criteria of 1 mm distance-to-agreement and 1% dose difference were used to evaluate the level of agreement of according profiles. Relative point and profile measurements were performed for all photon and electron beams of two Varian Clinacs 2100C/D. Matched beams show a good level of agreement. 70% of profiles completely pass the chosen criteria. The analysis of remaining 30% of the profiles demonstrates that measurement error becomes a limiting factor in achieving a better score. The highest obtained y value was 1.70. The quality of beam matching allowed us to treat according beams of both treatment units as "identical" and to use the reference beam data for the new unit. Nevertheless, the vendor's acceptance criteria of beam matching are much more benevolent. It might happen that the acceptance criteria are met, however, resulting quality of beam matching does not allow full interchangeability of beams.