Human Inhalation Study with Zinc Oxide: Analysis of Zinc Levels and Biomarkers in Exhaled Breath Condensate.

Workers in the zinc processing, for example, welding or hot-dip galvanizing, are exposed to aerosols consisting of particles and gases, including zinc oxide (ZnO), which can affect human health. In this study, we addressed the effects of short-term controlled exposure to nano-sized ZnO on the airway inflammatory markers in healthy volunteers. To this end, we determined the influence of ZnO inhalation on the content of zinc and biomarkers (leukotriene B4 (LTB4), peptide leukotrienes (LTC4/D4/E4), 8-iso-PGF2α, pH, and prostaglandin E2 (PGE2)) in exhaled breath condensate (EBC). Sixteen non-smoking subjects (8 females, 8 men) were exposed to filtered air (sham) or ZnO nanoparticles (0.5, 1.0, and 2.0 mg/m3) for 4 h. EBC samples were collected according to specific study design. We found that the peptide leukotrienes were below the limit of quantification (LOQ) in all the EBC samples. ZnO exposure showed no detectable effect on any other parameters investigated when comparing the two groups. The content of Zn in EBC was unaffected by ZnO inhalation at any concentration used. Therefore, we conclude that the evaluation of Zn and biomarker content in EBC would not be a suitable way to assess the exposure to inhaled ZnO.

Methodological Implications and Repeatability of Nasal Nitric Oxide: Relevance for Challenge Studies.

There is an interest in assessing changes in nasal NO (nNO) levels as an effect marker of upper airways. In this study, we examined methodologic influences on short and long term repeatability of nNO levels assessed by a portable electrochemical analyzer. Nine atopic and eighteen healthy subjects were exposed for 4 h to ethyl acrylate concentration of 0.05 ppm (sham) and mean concentrations of 5 ppm (either constant 5 ppm or variable 0 to 10 ppm). Sampling of nNO was performed by using passive aspiration during both breath-holding (634 ppb) or calm tidal breathing (364 ppb, p < 0.0001). The intra-session (between-session) repeatability in terms of coefficient of variation was 16.4% (18.5%) using the tidal-breathing and 8.6% (13.0%) using the breath-holding method, respectively. Atopic subjects demonstrated a significant increase in nNO (breath-holding mean 16%, tidal-breathing mean 32%) after applying a constant ethyl acrylate concentration (5 ppm). Our findings suggest that the less elaborate tidal-breathing method might be sufficient to detect significant changes at a group level. Given a lower coefficient of variation of breath-holding we assume there is an advantage of that approach at an individual level. Further research is needed to validate the usefulness of nNO in the evaluation of irritative, non-allergic responses.

[Temporary arthrodesis of the knee in two-stage septic prosthesis exchange : In vitro analysis of adhesion of Staphylococcus aureus on steel and carbon fiber rods]. / Temporäre Arthrodese des Kniegelenks bei zweizeitigem septischen Prothesenwechsel : In-vitro-Analyse der Adhäsion von Staphylococcus aureus auf Stahl- und Kohlefaserstäben.

BACKGROUND: In two-stage septic revision arthroplasty of the knee, a temporary intramedullary fixation with an antibiotic-containing polymethyl methacrylate (PMMA) spacer is often performed in cases of extensive bone defects after endoprosthesis explantation. A common method is the use of conventional steel or carbon fiber rods, which are connected via a tube-to-tube connector and finally reinforced near the joint with bone cement. OBJECTIVE: As the surface of foreign materials plays a critical role in the colonization and biofilm formation in the treatment of periprosthetic joint infections (PJI), the steel and carbon fiber rods were examined and compared with respect to bacterial surface adhesions. MATERIAL AND METHODS: Carbon fiber and steel rods of external fixator systems were used for this experimental study. The sample material was placed in a substrate enriched with S. aureus. The adherent bacteria were examined both by fluorescence microscopy and quantitatively after ultrasonic detachment (sonication) in a smear preparation. In addition, scanning electron micrograph (SEM) images were taken to analyze the topography of bacterial adhesions. RESULTS: The fluorescence microscopy revealed a uniform surface distribution for both materials. The observation of the SEM images showed that for carbon fiber rods the growth of bacteria ran in unison with the direction of the fiber, while for the steel rods an arbitrary arrangement was found. With the help of sonication a significant difference in the number of adherent micro-organisms between the two materials could not be determined using the Wilcoxon test (significance level p < 0.05). CONCLUSION: Both materials can be used to perform PMMA-reinforced intramedullary fixation without fear of sacrificing therapeutic success. From an economic point of view, the use of steel rods seems reasonable as the material costs are significantly lower.

Impact of Internal and External Factors on EBC-pH and FeNO Changes in Humans Following Challenge with Ethyl Acrylate.

Acute effects of ethyl acrylate exposure at 5 ppm for 4 h include changes of pH in exhaled breath condensate (EBC-pH) and exhaled nitric oxide (FeNO). So far, few data have been reported for atopic persons or the impact of the exposure conditions on biomarkers, e.g., constant versus variable application of irritants. Nine atopic and eighteen healthy volunteers without bronchial hyperresponsiveness were exposed for 4 h to ethyl acrylate concentrations of 0.05 ppm (sham), 5 ppm (constant concentration), and 0-10 ppm (variable, mean concentration of 5 ppm) in an exposure laboratory. A positive atopic status was defined according to specific IgE concentrations to common inhalant allergens (sx1 ≥ 0.35 kU/L). Biomarker levels were assessed before and after challenge and adjusted for levels after sham exposure (net response). Ethyl acrylate at constant, but not at variable concentrations induced a significant change in the net responses of EBC-pH and FeNO. Concerning FeNO, this could be observed only for atopic persons. The changes of biomarker levels were related to their baseline values. Biomarker responses to challenge with ethyl acrylate may be influenced by the patterns of application as well as baseline airway inflammation and atopic status of the volunteers.

Clinical Effects, Exhaled Breath Condensate pH and Exhaled Nitric Oxide in Humans After Ethyl Acrylate Exposure.

Ethyl acrylate is an irritant known to affect the upper airways and eyes. An increase of the eye blink frequency in humans was observed during exposure to 5 ppm. Studies on the lower airways are scant and our study objective was the evaluation of pH in exhaled breath condensate (EBC-pH) and nitric oxide in exhaled breath (FeNO) as markers of inflammation. Sixteen healthy volunteers were exposed for 4 h to ethyl acrylate at a concentration of 5 ppm and to sham (0.05 ppm) in an exposure laboratory. Clinical irritation symptoms, EBC-pH (at a pCO2 of 5.33 kPa) and FeNO were assessed before and after exposure. Differences after ethyl acrylate exposure were adjusted for those after sham exposure. 5 ppm ethyl acrylate induced clinical signs of local irritation in the nose and eyes, but not in lower airways. Exposure produced a subtle, but statistically significant, decrease in breathing frequency (1 breath/min; p = 0.017) and a lower EBC-pH (by 0.045 units; p = 0.037). Concerning FeNO, we did not observe significant changes compared to sham exposure. We conclude that local effects induced by 5 ppm ethyl acrylate consist of sensory irritation of eyes and nose. In addition, acute ethyl acrylate exposure to 5 ppm resulted in a net decrease of EBC-pH. Whether that can be interpreted in terms of additional lower airway irritation or already inflammatory alterations set in needs further investigations.

Different Patterns in Changes of Exhaled Breath Condensate pH and Exhaled Nitric Oxide After Ozone Exposure.

Study objective was the evaluation of pH in exhaled breath condensate (EBC-pH) and nitric oxide in exhaled breath (FeNO) as biomarkers of ozone induced inflammation. We recently demonstrated that an ozone exposure of 240 ppb is sufficient to reduce lung function indices. We enrolled ten healthy subjects exposed in an intermittent exercise protocol to ozone concentrations of 240 ppb and 40 ppb (sham exposure). EBC-pH and FeNO were assessed before (pre), immediately post (post), and 16 h after exposure (16 h). Findings are that compared to baseline, EBC-pH was significantly higher immediately after sham and ozone exposures, but not 16 h later. There was a negative net change in EBC-pH after adjusting for effects after sham exposure (net-ΔpHpost -0.38%, net-ΔpH16h -0.23%). Concerning FeNO, we observed no changes of values after sham exposure compared to baseline, but measured a significant lower net response at the end of exposure (net-ΔFeNOpost -17.5%) which was transient within 16 h (net-ΔFeNO16h -9.4%). We conclude that exercise known to enhance EBC-pH may compensate for EBC acidification associated with inflammation resulting in diminished change of this biomarker. Ozone imposes an oxidative burden and reactions between reactive oxygen species and NO might be an explanation for reduced FeNO levels.

Bone grafting in oblique versus prepared rectangular uncontained glenoid defects in reversed shoulder arthroplasty. A biomechanical comparison.

BACKGROUND: How the shape of the glenoid defect being reconstructed influences stability in reversed shoulder arthroplasty has never been evaluated. The purpose of this study was to compare the reconstruction of two different shaped defects in reversed shoulder arthroplasty. METHODS: Two groups (ten Sawbone scapulae each) of oblique- and rectangular-shaped glenoid defects were tested biomechanically. On the anterior half of the glenoid, bony defects (rectangular and oblique shaped) were prepared and reconstructed subsequently with a graft and reversed shoulder arthroplasty. As a control group, Sawbones without glenoid deficiency were used. In addition, these tests were reproduced in cadavers. FINDINGS: In Sawbones, no significant difference in initial stability was found between the two groups (p>0.05). Additionally, in the cadaver tests no significant difference was found between the groups with different defects (p>0.05). During the preparation, macroscopic loosening of the oblique bone grafts was found in three cases after the performance of the reversed shoulder arthroplasty due to the lack of medial support. The localization of the highest micromotion were measured primarily between the scapula bone and the graft compared to the measured micromotions between glenoid implant and the graft. INTERPRETATION: If the oblique-shaped bone graft was secured under the baseplate, the rectangular defect preparation did not show a significantly higher primary stability. However, the advantage of medial support in rectangular defects leads to more stability while placing the bone graft and baseplate during the surgical technique and should therefore be considered a preferable option.

Influence of different peg length in glenoid bone loss: A biomechanical analysis regarding primary stability of the glenoid baseplate in reverse shoulder arthroplasty.

BACKGROUND: There is no biomechanical basis to determine the influence of different length of the central peg of the baseplate anchored within the native scapula in glenoid defect reconstruction in cases of degenerative or posttraumatic glenoid bone loss in reversed shoulder arthroplasty. OBJECTIVE: The purpose of this study was to analyse the stability of different peg lengths used in glenoid bone loss in reversed shoulder arthroplasty. METHODS: Different lengths of metaglene pegs with different depths of peg anchorage performed with or without metaglene screws in sawbone foam blocks were loaded in vertical and horizontal directions for differentiating load capacities. Simulated physiological loadings were then applied to the peg implants to determine the limits of loading in each depth of anchorage. RESULTS: The loading capacity of the implant was reduced as less of the peg was anchored. The vertically loaded implants showed a significantly higher stability, in contrast to those loaded horizontally at a corresponding peg length and depth of anchorage (p < 0.05). The tests revealed that the metaglene screws are more essential for primary stability than is the peg particularly in the vertically directed loadings (2/3 anchored: peg contributed to 28% of the stability, 1/3 anchorage: peg contributed to 12%). Under the second test conditions, the lowest depth of peg anchorage (1/3) resulted in 322 Newtons [N] in the long peg with a vertical loading direction, and in 130 N in the long peg with a horizontal loading direction (p < 0.05). CONCLUSION: The pegs should be anchored as deeply as possible into the native scapula bone stock. The metaglene screws play a major role in the initial stability, in contrast to the peg, and they become more important when the depth of the peg anchorage is reduced. If possible, four metaglene screws should be used in cases of uncontained bone loss to guarantee the highest stability.