A novel method for the accurate quantification of two isomeric mercapturic acids of 1,3-dichlorobenzene in human urine using isotope dilution online-SPE-LC-MS/MS.

1,3-dichlorobenzene (1,3-DCB) is an aromatic solvent that might be formed during thermal decomposition of bis(2,4-dichlorobenzoyl)peroxide used as initiator in silicone rubber production with many workers exposed worldwide. During metabolism of 1,3-DCB, two isomeric mercapturic acids can be formed from ring oxidation of 1,3-DCB in the liver, namely 2,4-dichlorophenylmercapturic acid (24CPhMA) and 3,5-dichlorophenylmercapturic acid (35CPhMA). These urinary mercapturic acids might serve as biomarkers of the toxicologically relevant absorbed dose of 1,3-DCB and have not been determined so far. Thus, we were aimed to develop an analytical method for quantification of these biomarkers. Authentic standards of both mercapturic acids as well as deuterium-labelled analogues were self-synthesized. A method for the quantification of both CPhMAs in human urine using online-SPE LC/MS/MS was developed and validated with an LOQ of 0.1 ng mL-1 for both CPhMAs. The analytes were extracted from urine by online-SPE on a restricted access material phase, transferred to the analytical column and quantified by tandem mass spectrometry. Interday (n = 6) and Intraday (n = 10) precision for both CPhMAs ranged from 1.7 to 4.3 % with accuracies between 99.4 and 109.9 % at concentrations of 0.6 and 3 ng mL-1. We applied the method on post-shift urine samples of 16 workers of the silicone rubber industry with occupational exposure to 1,3-DCB. Both CPhMAs were above LOQ in 15 of 16 urine samples with median levels (range) for 24CPhMA and 35CPhMA of 1.64 ng mL-1 (<0.1 - 8.2 ng mL-1) and 3.98 ng mL-1 (0.36 - 24.1 ng mL-1), respectively. This is the first report on specific urinary mercapturic acids of 1,3-DCB in humans. Our results show that ring oxidation of 1,3-DCB is considered to be a toxicologically relevant metabolic pathway in humans. This might improve risk assessment of 1,3-DCB-emissions in silicone rubber industry.

New data on the metabolism of chloromethylisothiazolinone and methylisothiazolinone in human volunteers after oral dosage: excretion kinetics of a urinary mercapturic acid metabolite ("M-12").

Methylisothiazolinone (MI) as well as the mixture of chloromethylisothiazolinone/methylisothiazolinone [MCI/MI (3:1)] are biocides that are used in a variety of products of every-day life. Due to the skin sensitizing properties of these biocides, their use has come under scrutiny. We have previously examined the human metabolism of MI and MCI after oral dosage of isotope-labelled analogues in human volunteers and confirmed N-methylmalonamic acid to be a major, but presumably unspecific human urinary metabolite. In the present study, we have investigated the urinary kinetics of a mercapturic acid metabolite of MI and MCI using the same set of samples. Four human volunteers received 2 mg of isotopically labelled MI and MCI separately and at least 2 weeks apart. Consecutive urine samples were collected over 48 h and were examined for the content of the (labelled) 3-mercapturic acid conjugate of 3-thiomethyl-N-methyl-propionamide ("M-12"), a known metabolite in rats. On a molar basis, M-12 represented 7.1% (3.0-10.1%) of the dose excreted in urine after dosage of MI. Excretion of this mercapturate was fast with a mean half-life of 3.6 h. Surprisingly, for MCI the mercapturate M-12 represented only 0.13% of the dose excreted in urine. Thus, this biomarker is highly specific for exposures to MI and might be used to distinguish between different exposure patterns of these biocides [use of MI or MCI/MI (3:1)] in the general population.

[Update of the AWMF S2k Guideline "Diagnostics and Assessment of Occupational Asbestos-Related Diseases" - What's New?] / Update der AWMF-S2k-Leitlinie "Diagnostik und Begutachtung asbestbedingter Erkrankungen" ­ Was gibt es Neues?

The S2k guideline "Diagnostics and assessment of occupational asbestos-related diseases" was updated in November 2020. This article summarizes the most important changes. There is a new reference to the risk of potentially high exposures to asbestos fibers when renovating plaster, fillers and adhesives containing asbestos.Biomarkers such as mesothelin and calretinin should currently only be used in the context of research. The "asbestos airways disease", which can only be diagnosed histologically, is included in the guideline as an early form of asbestosis. Since the UIP pattern is not characteristic of asbestosis, computed tomography cases with UIP patterns alone cannot be assigned reliably to asbestosis without the simultaneous detection of pleural plaques. With regard to the evaluation of the functional damage, attention is drawn to the importance of flow volume curve, whole-body plethysmography, diffusion capacity and exercise testing. If available, the reference values ​​according to GLI are the basis of the assessment. The guideline contains specific recommendations on prevention, medical treatment and, for the first time, on the importance of outpatient rehabilitation and training therapy. There are also references to the assessment of the new occupational disease ovarian cancer after occupational exposure to asbestos.

Neuropsychological effects of occupational exposure to polychlorinated biphenyls.

In the context of a health surveillance program for former PCB-exposed workers of a transformer and capacitor recycling company in Germany, their family members, employees of surrounding companies and area residents a broad range of cognitive functions covering attention, executive processing, reasoning, memory and motor performance was examined. The study aimed at identifying potential adverse effects of PCB load on cognitive functions. Detailed analysis of PCB burden of the participants revealed rather high correlations of lower and higher chlorinated as well as dioxin-like PCBs. Nearly one half of the participants exhibited increased burden in all three PCB classes whereas only 33 out of 237 participants did not show any increased PCB burden. Thus, data analysis followed a two-fold strategy: (1) Based on studies providing data on PCB exposure of the German general population the PCB burden of every participant was classified as normal (percentile rank PR <95) or increased (PR ≥95). Increased burden with respect to lower (LPCBs) and higher chlorinated (HPCBs) as well as dioxin-like (dlPCBs) PCBs was assumed if a participant showed at least one congener surpassing the PR95 criterion for the respective congener class and (2) Overall plasma PCB level per congener class was used as measure of PCB load. In a multivariate approach using structural equation modelling and multiple regression analysis we found a significant impact of PCBs on word fluency and sensorimotor processing irrespective of the measure of PCB burden (PR95 criterion or overall plasma level). However, no effect of PCB burden on memory, attention, and cognitive flexibility could be demonstrated. Particularly, an increase of LPCBs was associated with an overall reduction of verbal fluency of letter and semantic word generation as well as word production based on a single or two alternating criteria. In addition, participants with increased burden of LPCBs exhibited a time-on-task effect in terms of a stronger decline of performance with increasing duration of the verbal fluency task. Moreover, we found adverse effects of HPCBs on Aiming and of dlPCBs on Line Tracking. Results are discussed in terms of (1) a decrease of cerebral dopamine (DA) with non-coplanar PCBs resulting in an impact on fronto-striatal cerebral structures subserving verbal fluency and motor processing, (2) a PCB-induced reduction of norepinephrine leading to the time-on-task effect with verbal fluency, and (3) adverse effects of PCBs on dopaminergic receptors in the cerebellum resulting in impaired fine motor function.

Quantification of six potential unspecific human biomarkers of 1-vinyl-2-pyrrolidone exposure in Sprague-Dawley rat urine using gas chromatography coupled with triple mass spectrometry.

RATIONALE: The monomer 1-vinyl-2-pyrrolidone (VP) is a substance with excellent solvent features. It is used in a wide variety of pharmaceutical, cosmetic, food industrial or technical applications and produced on an industrial scale. Since VP has caused adenocarcinoma of the nasal cavity and liver cell carcinoma in long-term experiments with rats, a human biomarker would be appreciated for risk assessment. METHODS: A sensitive analytical electron ionization gas chromatography/tandem mass spectrometry (GC/MS/MS) method for the determination of six possible biomarkers for VP in urine was established and validated. Two isotope-labeled internal standards (ISTD) were used for quantification. A simple and easy to use freeze-drying step was performed prior to derivatization with N-tert-butyldimethylsilyl-N-methyltrifluoracetamide (MTBSTFA) and following sample extraction for cleanup purposes. RESULTS: A calibration curve with six calibration standards ranging from 50 µg/L to 2000 µg/L (10-fold higher for H-OPAA) in urine was prepared. Validation results were satisfactory with recoveries ranging from 88.2 to 110.2 % with two exceptions for the lowest quality control for two substances without ISTD (126.4 % and 139.3 %). Three of the substances could be identified as VP metabolites in an exposure study with Sprague-Dawley (SD) rats. CONCLUSIONS: A quick and easy to use method has been established for six target molecules investigated for a better understanding of the metabolism of VP. Two of three substances identified as metabolites of VP could serve as a nonspecific human biomarker for VP exposure as shown with an excerpt of an exposure study performed in SD rats.

Analysis of the biliostatic potential of two sealants in a standardized porcine model of liver resection.

BACKGROUND: Improved resection techniques has decreased mortality rate following liver resections(LRx). Sealants are known as effective adjuncts for haemostasis after LRx. We compared biliostatic effectiveness of two sealants in a standardized porcine model of LRx. MATERIAL AND METHODS: We accomplished left hemihepatectomy on 27 pigs. The animals were randomized in control group(n = 9) with no sealant and treatment groups (each n = 9), in which resection surfaces were covered with TachoSil® and TissuFleece®/Tissucol Duo®. After 5 days the volume of ascites(ml), bilioma and/or bile leakages and degree of intra-abdominal adhesions were analysed. RESULTS: Proportion of ascites was lower in TissuFleece/Tissucol Duo® group. The ascites volume was lower in TachoSil® group. In sealant groups, increased adhesion specially in the TachoSil® group was seen. A reduction of the "bilioma rate" was seen in sealant groups, which was significantly lower in TissuFleece®/Tissucol Duo® group. CONCLUSION: In a standardized condition sealants have a good biliostatic effect but with heterogeneous potentials. This property in combination with the cost-benefit analysis should be the focus of future prospective studies.

Imetelstat, a telomerase inhibitor, differentially affects normal and malignant megakaryopoiesis.

Imetelstat (GRN163L) is a specific telomerase inhibitor that has demonstrated clinical activity in patients with myeloproliferative neoplasms (MPN) and in patients with solid tumors. The antitumor effects were associated with the development of thrombocytopenia, one of the common side effects observed in patients treated with imetelstat. The events underlying these adverse effects are not apparent. In this report, we investigated the potential mechanisms that account for imetelstat's beneficial effects in MPN patients and the manner by which imetelstat treatment leads to a reduction in platelet numbers. Using a well-established system of ex vivo megakaryopoiesis, we demonstrated that imetelestat treatment affects normal megakaryocyte (MK) development by exclusively delaying maturation of MK precursor cells. By contrast, additional stages along MPN MK development were affected by imetelstat resulting in reduced numbers of assayable colony-forming unit MK and impaired MK maturation. In addition, treatment with imetelstat inhibited the secretion of fibrogenic growth factors by malignant but not by normal MK. Our results indicate that the delay observed in normal MK maturation may account for imetelstat-induced thrombocytopenia, while the more global effects of imetelstat on several stages along the hierarchy of MPN megakaryopoiesis may be responsible for the favorable clinical outcomes reported in MPN patients.

Quantification of N-methylmalonamic acid in urine as metabolite of the biocides methylisothiazolinone and chloromethylisothiazolinone using gas chromatography-tandem mass spectrometry.

Methylisothiazolinone and the mixture of chloromethylisothiazolinone/methylisothiazolinone (MCI/MI, 3:1) are widespread biocides used in cosmetic and household products. Due to their skin permeability, they might be taken up by the general population via use of products containing these biocides. As both compounds are known skin sensitizers, the use of these products is under discussion by regulatory agencies. In order to evaluate the possible uptake of MI and/or MCI/MI by human biomonitoring, we have developed and validated a highly sensitive and specific GC/MS/MS-method for the quantification of N-methylmalonamic acid (NMMA), a known metabolite of MI and MCI in urine of rats. After freeze-drying of urine, the analyte is derivatised with pentafluorobenzyl bromide in anhydrous solution and the PFB-derivative is extracted into n-hexane. After concentration, the derivative is finally quantified by GC/MS/MS in EI-mode using 13C3-NMMA as internal standard. The limit of quantification for NMMA was 0.5ngmL-1 urine. Precision within and between-series was determined to range between 3.7-10.9% using native and spiked quality control samples. Accuracy ranged between 89 and 114%. In a pilot study we applied this method to spot urine samples of 63 persons not knowingly exposed to MI and/or MCI/MI. NMMA was quantifiable in every urine sample analysed, with no significant difference in urinary levels between male and female participants. The median (95th percentile) levels for urinary NMMA were 3.6 (7.4) ngmg-1 creatinine and 2.9 (9.1) ngmg-1 creatinine for males (n=32) and females (n=31), respectively. In a volunteer experiment, a relation of exposure to MI and/or MCI/MI and subsequent NMMA-excretion was shown. Our method is the first to report human urinary background levels of NMMA. However, the possibility of formation and urinary excretion of NMMA within physiological processes cannot be ruled out.

[Intramedullary nailing in diaphyseal clavicle fractures using minimally invasive percutaneous reduction]. / Die intramedulläre Nagelung der diaphysären Klavikulafraktur in minimal-invasiver Repositionstechnik.

OBJECTIVE: Closed reduction and intramedullary nailing is common in diaphyseal clavicle fractures. The aim of this report is to demonstrate a surgical method with minimally invasive percutaneous reduction in cases where closed reduction fails. The procedure is associated with good cosmetic results. INDICATIONS: Percutaneous reduction using two reduction forceps enables intramedullary nailing without an open procedure. CONTRAINDICATIONS: Open, multifragmented or non-dislocated fractures, oblique fractures due to postoperative dislocation or shortening risk, fracture having potential to become compound fractures, neurovascular complications, pseudoarthroses. SURGICAL TECHNIQUE: The patient is in beach-chair position. After an incision, the nail is entered from medial, two reduction forceps are mounted percutaneously at the lateral and medial fragment. After reduction the nail is pushed forward into the lateral fragment. Thereby, the fracture hematoma is not disturbed for the most part. POSTOPERATIVE MANAGEMENT: Early functional rehabilitation with maximal abduction and anteversion of 90° for 6 weeks. RESULTS: Anatomic reduction can be achieved with mild cosmetic impairment.

[Guideline (S2k, AWMF) of the Deutsche Gesellschaft für Pneumologie und Beatmungsmedizin and the Deutsche Gesellschaft für Arbeitsmedizin und Umweltmedizin "Diagnostics and Expert Opinion in the Occupational Disease No. 4101 Silicosis (Including Coal Worker's Pneumoconiosis)"]. / S2k-Leitlinie nach AWMF-Schema der Deutschen Gesellschaft für Pneumologie und Beatmungsmedizin und der Deutschen Gesellschaft für Arbeitsmedizin und Umweltmedizin "Diagnostik und Begutachtung der Berufskrankheit Nr. 4101 Quarzstaublungenerkrankung (Silikose) der Berufskrankheitenverordnung".

During the last 1.5 years an update of the guideline on silicosis was made by an interdisciplinary working group. New medical and scientific knowledge and the experience in expert opinion practice were taken into account.By preparing the initial guideline in 2010 standardization of diagnostics and adaption of the "Moers convention" which was not based on medical knowledge was in the focus, whereas the current update deals with fine emendation and extension, especially of the compensation rate (adaption with the Reichenhall recommendation).The diagnosis of silicosis (including mixed dust pneumoconiosis) is based on a detailed occupational history, and predominantly on the typical radiological findings. However, at initial diagnosis the standardized LD-HRCT takes an important role because of its high sensitivity and specificity. Exceptional cases are those with characteristic findings in chest X-ray follow-up. Correspondingly, it is mentioned in the guideline: "The standardized appraisal of the Low-Dose-Volume HRCT requires application of the CT classification (ICOERD, International Classification of Occupational and Environmental Respiratory diseases). In order to diagnose silicosis in CT scan opacities with sharp borders in both central upper lung fields and their circumferencies have to be documented. By comparing with ILO standard radiographs at least profusion category 1 in the right and left upper lung fields has to be reached (total profusion category 2)."The pathologic minimal requirement for the diagnosis of silicosis which has undergone controversial discussion has now also been defined. Corresponding to Hnizdo et al. 2000 it is now mentioned: "Finding of less than 5 silicotic granuloma per lung lobe by palpation is regarded as insignificant." This is a convention and not a threshold based on detailed medical scientific and statistical studies; it is based on extended experience in the South African gold mines.This guideline also deals with silicotic hilar (and sometimes mediastinial) lymph nodes; according to the guideline working group they do not closely correlate with the degree of pulmonary involvement. Extended conglomerating and enduring lymph-node processes may lead to dislocation of the hili with impairment of large bronchi and vessels. Shell-like calcifications dominating in the periphery of lymph nodes produce so-called egg-shell hili.The paragraph on exercise testing is now extended: if neither ergometry nor spiroergometry can be performed a 6 minute walking test by measuring oxygen saturation should be done.Furthermore, in individual expert opinion examinations right heart catheterization (the patient is not obliged to give informed consent) may be recommended, if echo cardiography gives evidence for pulmonary hypertension or if it is difficult to differentiate between right and left heart failure. The presence of pulmonary hypertension which is of prognostic relevance has to be considered when grading reduction in earning capacity.For interpretation of spirometry values the new GLI reference values has to be applied. Grading of impairment is due to the recommendation of the DGP.According to current medical scientific knowledge it is unclear, whether certain disorders of the rheumatic group such is scleroderma or Caplan syndrome which are sometimes associated with silicosis (or coal workers' pneumoconiosis) belong in toto to the occupational disease number 4101 (silicosis). Within this context, additional studies are needed to clarify the role of occupational quartz exposure and other risk factors.The guideline working group hopes that this update will help to optimize diagnostics and expert opinion of silicotic patients.

IL-6, a central acute-phase mediator, as an early biomarker for exposure to zinc-based metal fumes.

AIMS: Systemic C-reactive protein (CRP) increases 1day after short-term inhalation of welding fumes containing zinc and/or copper. The aim of the current study was to find further, possibly earlier systemic biomarkers after inhalation of different welding fumes containing zinc and traces of aluminum, with or without copper, as these metal combinations become more common in modern joining technology. METHODS: The study group consisted of 15 non-smoking male volunteers with healthy lung function data and without any occupational metal fume exposure. On 4 different exposure days, the members of the study group were exposed under controlled conditions to ambient air or 3 different welding fumes for 6h. Spirometric and impulse oscillometric measurements and differential blood counts were performed and serum samples were collected before exposure and 6, 10 and 29h after start of exposure. The biomarker concentrations in serum were measured by electrochemiluminescent assays. RESULTS: Systemic increases of IL-6 peaked significantly at 10h compared to baseline ("ZincZinc": P=0.0005 (median increase (m. incr.)=1.36pg/mL); "ZincAlu": P=0.0012 (m. incr.=1.48pg/mL); "AluBronze": P=0.0005 (m. incr.=2.66pg/mL)). At 29h, CRP and serum amyloid A (SAA) increased distinctively ("ZincZinc": P=0.032 (m. incr.=0.65µg/mL) [CRP], 0.077 (m. incr.=0.61µg/mL) [SAA]; "ZincAlu": P=0.001 (m. incr.=1.15µg/mL) [CRP], 0.0024 (m. incr.=0.94µg/mL) [SAA]; "AluBronze": P=0.002 (m. incr.=2.5µg/mL) [CRP], 0.002 (m. incr.=0.97µg/mL) [SAA]). The median increases of CRP and IL-6 were most pronounced for the welding fume which contained besides zinc also copper (AluBronze). For differentiating AluBronze from control exposure, receiver operating characteristic (ROC) curve analysis was performed and the area under the ROC curve (AUC) for the IL-6 increases (10h versus 0h) was 0.931. The additional inflammatory mediators [vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), interferon-γ (IFN-γ), cell counts] and the lung function parameters did not show any significant changes after exposure. CONCLUSIONS: Consistent with its role of the mediation of the acute-phase response, systemic increases of IL-6 after welding fume exposure peak at 10h before the increases of the acute-phase reactants CRP and SAA at 29h. IL-6 may represent a highly sensitive and early biomarker for the exposure to metal fumes containing zinc and copper. As IL-6, CRP and SAA are independent, strong risk markers for future cardiovascular diseases, these data may particularly be important for long-term welders with respect to their cardiovascular health.

Isotope-dilution method for the determination of 1-vinyl-2-pyrrolidone-mercapturic acid as a potential human biomarker for 1-vinyl-2-pyrrolidone via online SPE ESI-LC/MS/MS in negative ionization mode.

We established and validated a specific and sensitive analytical method for the determination of 1-vinyl-2-pyrrolidone (VP) as 1-vinyl-2-pyrrolidone-mercapturic acid (VPMA) in urine using an electrospray liquid chromatography tandem mass spectrometry (ESI-LC/MS/MS) column switching method. An online solid phase extraction (SPE) for sample cleanup was performed by column switching to a restricted access material and back-flushing to the analytical column. A Phenomenex Luna C8 column was used for sample separation (150mm; ID 4,6mm; 3µm). D4-VPMA served as an isotope labeled internal standard and was detected in negative multiple-reaction monitoring (MRM) mode. The Limit of quantification (LOQ) for VPMA was 1.5µg/L, the intra-day precision of three concentrations (2µg/L, 75µg/L and 400µg/L) of spiked urine samples ranged from 2.7 to 7.3%, the inter-day precision from 3.4 to 14.4%. The accuracy ranged from 6.2 to 9.0%, for the intra-day experiments and from 0.3 to 6.9% for the inter-day experiments. The method was applied to urines of Sprague-Dawley rats exposed to VP as a proof of principle of VPMA as a potential biomarker.

Acute MCL and ACL injuries: first results of minimal-invasive MCL ligament bracing with combined ACL single-bundle reconstruction.

BACKGROUND: There is an on-going discussion whether to operatively treat combined grade II and III lesions of the medial collateral ligament (MCL) with anterior cruciate ligament (ACL) in the acute phase rather than conservative treatment of the MCL lesion with a delayed unitary ACL replacement. Another issue is the question how to technically address these MCL lesions. The aim of this study was, therefore, to analyze the results of simultaneous ACL replacement (hamstrings) in a single-bundle technique with a simultaneous MCL ligament bracing procedure. METHODS: In this prospective non-randomized trial,, 16 patients were included with grade II and III lesions of the MCL. Surgical treatment was performed within 14 days (mean 10.4 days, SD ±2.3 days) by one single expert orthopedic surgeon using the semitendinosus tendon and Rigidfix® system for femoral and tibial fixation and 3.5 mm screws with one 1.3 mm PDS Cord for minimal-invasive MCL ligament bracing with screw fixation. Knee stability was measured with the Rolimeter® and KT-1000®. MCL stability was assessed in clinically and radiographically with valgus stress projections. RESULTS: The mean patient age was 36.4 with six female and ten male patients. There were no surgical complications such as infections or healing disturbances. Mean operation time was 64 ± 6 min. The arthrofibrosis rate was 0 %. Medial knee stability was normal in full extension for all cases with no intra-individual side-to-side difference. Radiological assessed MCL stability revealed Δ values with a mean of 1.1 ± 1.3 mm compared to the contra-lateral side. The Lachman Test revealed a side-to-side difference of 1.6 mm with the KT-1000® and 2.6 ± 0.9 mm when measured with the Rolimeter®. Subjective clinical assessment revealed good results with a mean Lysholm Score of 89.1 points. CONCLUSION: Acute ACL replacement and MCL ligament bracing with this novel technique revealed in this study good clinical results and objective restored knee stability without cases of knee stiffness or arthrofibrosis. The remarkable shortcoming is the small cohort number making further studies necessary.

Biological effects of inhaled nitrogen dioxide in healthy human subjects.

PURPOSE: Several epidemiological studies indicate that inhaled nitrogen dioxide (NO2) at low concentrations have been statistically associated with adverse health effects. However, these results are not reflected by exposure studies in humans. The aim of the study was to assess the acute functional and cellular responses to different NO2 concentrations in healthy human subjects with various techniques. METHODS: Twenty-five subjects were exposed for 3 h to NO2 concentrations 0, 0.1, 0.5, and 1.5 ppm in a randomized crossover study design during 4 consecutive weeks. In each subject, lung function, diffusion capacity and exhaled nitric oxide were measured and inflammation markers were assessed in blood, nasal secretions, induced sputum and exhaled breath condensate. RESULTS: From all lung function indices under consideration, only intrathoracic gas volume was borderline significantly increased after 0.5 ppm (p = 0.048) compared to 0.1 ppm NO2. Regarding the cellular effect parameters, the macrophage concentration in induced sputum decreased with increasing NO2 concentration, although these changes were only borderline significant (p = 0.05). CONCLUSION: These results do not suggest a considerable acute adverse response in human subjects after 3 h of exposure to NO2 in the NO2 concentration range investigated in this study.

Stem cells and bFGF in tendon healing: Effects of lentiviral gene transfer and long-term follow-up in a rat Achilles tendon defect model.

BACKGROUND: The influence of stem cells and lentiviral expression of basic fibroblastic growth factor (bFGF) on tendon healing and remodelling was investigated in an in-vivo long-term (12 weeks) rat Achilles tendon defect model. METHODS: In sixty male Lewis rats, complete tendon defects (2.4 mm) were created and either left untreated (PBS) or treated by injection of stem cells lentivirally expressing the enhanced green fluorescence marker gene eGFP (MSC-LV-eGFP) or basic fibroblast growth factor bFGF (MSC-LV-bFGF). Tendons were harvested after 12 weeks and underwent biomechanical and (immuno)-histological analysis. RESULTS: After 12 weeks the mean ultimate load to failure ratio (treated side to contralateral side) in biomechanical testing reached 97 % in the bFGF-group, 103 % in the eGFP-group and 112 % in the PBS-group. Also in the stiffness testing both MSC groups did not reach the results of the PBS group. Histologically, the MSC groups did not show better results than the control group. There were clusters of ossifications found in all groups. In immunohistology, only the staining collagen-type-I was strongly increased in both MSC groups in comparison to PBS control group. However, there were no significant differences in the (immuno)-histological results between both stem cell groups. CONCLUSION: The biomechanical and (immuno)-histological results did not show positive effects of the MSC groups on tendon remodelling in a long-term follow-up. Interestingly, in later stages stem cells had hardly any effects on biomechanical results. This study inspires a critical and reflected use of stem cells in tendon healing.

Predictors of outcome after single-event multilevel surgery in children with cerebral palsy: a retrospective ten-year follow-up study.

AIMS: Single event multilevel surgery (SEMLS) has been shown to improve gait in children with cerebral palsy (CP). However, there is limited evidence regarding long-term outcomes and factors influencing them. METHODS: In total 39 children (17 females and 22 males; mean age at SEMLS ten years four months, standard deviation 37 months) with bilateral CP (20 Gross Motor Function Classification System (GMFCS) level II and 19 GMFCS level III) treated with SEMLS were included. Children were evaluated using gait analysis and the Gait Deviation Index (GDI) before SEMLS and one, two to three, five and at least ten years after SEMLS. A linear mixed model was used to estimate the effect of age at the surgery, GMFCS and follow-up period on GDI. RESULTS: There was a mean improvement of 12.1 (-15.3 to 45.1) GDI points one year after SEMLS (p < 0.001) and 10.3 (-23.1 to 44.2) GDI points ten years after SEMLS compared with before SEMLS (p < 0.001). GMFCS level III children aged ten to 12 years had the most improvement. The GMFCS III group had more surgical procedures at the index SEMLS (p < 0.001) and during the follow-up period (p = 0.039). After correcting for other factors, age at surgery was the only factor predictive of long-term results. Our model was able to explain 45% of the variance of the change in GDI at the different time points. TAKE HOME MESSAGE: Children with GMFCS III level aged ten to 12 are the benchmark responders to SEMLS in the long-term.

[Pearls and pitfalls for the treatment of tibial head fractures]. / Outcome und Komplikationen nach proximalen Tibiafrakturen.

BACKGROUND: Tibial plateau fractures requiring surgery are severe injuries of the lower extremity. Depending on the fracture pattern, the age of the patient, the range of activity and the bone quality there is a broad variation in adequate treatment. In the last decade we have had a tremendous development, might it be the angular stable anatomical plates as well as new approaches to the proximal tibia. Nevertheless in the recent literature there are still many complications reported. Not only for sports professionals, recreational athletes or heavy load workers tibial plateau fractures affect leisure, all day activity and professional life. This article reports the treatment algorithm showing different cases, outlines the pitfalls and explains treatment strategies with a detailed x-ray follow-up. CONCLUSION: After a tibial plateau fracture patients are affected in their sporting activity due to an impaired knee function. Despite a long rehabilitation time and programs, physical activity changes to lower impact sports. Among the usual perioperative complications there are the specific complications of postoperative malalignment, implant infections, osteitis of the tibial head, compartment syndrome, secondary loss of reduction, avascular tibial head necrosis, secondary varus or valgus deformity, post-traumatic arthrosis and lesions of the peroneal nerve. In the literature in up to 43% of the cases complications have been noted. Despite surgery the majority of patients cannot return to their previous level of activity. However, overall about 70% of the patients return to sports after a tibial plateau fracture. For a beneficial outcome a detailed fracture analysis with CT scan and precise planning of the surgical strategies and approaches is mandatory.

[Balloon osteoplasty as reduction technique in the treatment of tibial head fractures]. / Ballonaugmentation als Repositionstechnik bei der Versorgung von Tibiakopffrakturen.

BACKGROUND: Tibial plateau fractures requiring surgery are severe injuries of the lower extremities. Depending on the fracture pattern, the age of the patient, the range of activity and the bone quality there is a broad variation in adequate treatment.  AIM: This article reports on an innovative treatment concept to address split depression fractures (Schatzker type II) and depression fractures (Schatzker type III) of the tibial head using the balloon osteoplasty technique for fracture reduction. METHODS: Using the balloon technique achieves a precise and safe fracture reduction. This internal osteoplasty combines a minimal invasive percutaneous approach with a gently rise of the depressed area and the associated protection of the stratum regenerativum below the articular cartilage surface. This article lights up the surgical procedure using the balloon technique in tibia depression fractures. CONCLUSION: Using the balloon technique a precise and safe fracture reduction can be achieved. This internal osteoplasty combines a minimally invasive percutaneous approach with a gentle raising of the depressed area and the associated protection of the regenerative layer below the articular cartilage surface. Fracture reduction by use of a tamper results in high peak forces over small areas, whereas by using the balloon the forces are distributed over a larger area causing less secondary stress to the cartilage tissue. This less invasive approach might help to achieve a better long-term outcome with decreased secondary osteoarthritis due to the precise and chondroprotective reduction technique.

Simple and sensitive GC/MS-method for the quantification of urinary phenol, o- and m-cresol and ethylphenols as biomarkers of exposure to industrial solvents.

We have developed and validated a simple and sensitive method for the determination of urinary phenol as well as the urinary metabolites of toluene and ethylbenzene in one analytical run. After enzymatic hydrolysis for the cleavage of conjugates overnight, the analytes are extracted from the matrix with a liquid-liquid extraction procedure using toluene as solvent under acidic conditions. The analytes are then derivatised to volatile ethers using N,O-bis(trimethylsilyl) trifluoroacetamid (BSTFA) for cresols and ethylphenols as well as N-tert-butyldimethylsilyl-N-methyltrifluoroacetamid (MTBSTFA) for the determination of phenol. Separation and detection was carried out using capillary gas chromatography with mass-selective detection (GC-MS). Deuterium-labeled o-cresol served as internal standard for the quantification of all metabolites and guaranteed good accuracy of the results. No matrix effects were observed in the quantification of the analytes. The limit of detection for o- and m-cresol and 2- and 4-ethylphenol was 10 and 20µg/l urine and linearity ranged up to 3 and 12mg/L urine, respectively. The limit of detection for urinary phenol was 0.5mg/L with a linear range up to 200mg/L. The relative standard deviation of the within-series imprecision ranged between 3.0 and 7.2% at two spiked concentrations of 60 and 400µg/l and the relative recovery was between 84 and 104%, depending on the analyte. The method was successfully applied in proficiency testing for urinary o-cresol and phenol. This method was used for the analysis of urine samples of 17 non-smoking and 13 smoking persons from the general population without known exposure to solvents. Smokers showed a significantly higher excretion of o-cresol (median: 23 vs. 33µg/l), m-cresol (median: 43 vs. 129µg/l) as well as 4-ethylphenol (median: 25 vs. 124µg/l). Especially excretion of 4-ethylphenol was significantly correlated to smoking habits. The method seems to be suitable for biological monitoring of low-level solvent exposures and allows determination of background values in the general population.