Digital Staining of White Blood Cells With Confidence Estimation.

Chemical staining of the blood smears is one of the crucial components of blood analysis. It is an expensive, lengthy and sensitive process, often prone to produce slight variations in colour and seen structures due to a lack of unified protocols across laboratories. Even though the current developments in deep generative modeling offer an opportunity to replace the chemical process with a digital one, there are specific safety-ensuring requirements due to the severe consequences of mistakes in a medical setting. Therefore digital staining system would profit from an additional confidence estimation quantifying the quality of the digitally stained white blood cell. To this aim, during the staining generation, we disentangle the latent space of the Generative Adversarial Network, obtaining separate representation s of the white blood cell and the staining. We estimate the generated image's confidence of white blood cell structure and staining quality by corrupting these representations with noise and quantifying the information retained between multiple outputs. We show that confidence estimated in this way correlates with image quality measured in terms of LPIPS values calculated for the generated and ground truth stained images. We validate our method by performing digital staining of images captured with a Differential Inference Contrast microscope on a dataset composed of white blood cells of 24 patients. The high absolute value of the correlation between our confidence score and LPIPS demonstrates the effectiveness of our method, opening the possibility of predicting the quality of generated output and ensuring trustworthiness in medical safety-critical setup.

Precise blood proteome profiling in an undiagnosed population with COVID-19.

Self-sampled blood provided valuable information about the COVID-19 seroprevalence in the general population. To enable an even deeper understanding of pathophysiological processes following SARS-CoV-2 infections, 276 circulating proteins were quantified by proximity extension assays in dried blood spots (DBS). Samples from undiagnosed individuals collected during the first wave of the pandemic were selected based on their serological immune response and matched on self-reported symptoms. We stratified these as seropositive (IgM+IgG+; N = 41) or seronegative (IgM-IgG-; N = 37), and to represent the acute (IgM+IgG-; N = 26) and convalescent phases (IgM-IgG+; N = 40). This revealed proteins from a variety of clinical processes including inflammation and immune response (MBL2, MMP3, IL2RA, FCGR2A, CCL5), haemostasis (GP1BA, VWF), stress response (ANG), virus entry (SDC4) or nerve regeneration (CHL1). The presented approach complements clinical surveys and enables a deep molecular and population-wide analysis of COVID-19 from blood specimens collected outside a hospital setting.

Change in out-of-hospital 12-lead ECG diagnostic classification following resuscitation from cardiac arrest.

INTRODUCTION: We evaluated the incidence of change in serial 12-lead electrocardiogram (ECG) diagnostic classifications in patients resuscitated from out-of-hospital (OH) cardiac arrest (OHCA) comparing OH to emergency department (ED) ECGs. METHODS: This retrospective case series included: 1) adults (≥ 18 years old), 2) resuscitated from OHCA, 3) ≥ 1 OH and 1 ED ECG/patient, and 4) emergency medical services (EMS) transport to the study hospital. OH and ED ECGs were classified as: 1) STEMI (ST-segment Elevation Myocardial Infarction), 2) Ischemic, and 3) Non-ischemic. Two ED physicians and one cardiologist independently classified all ECGs, then generated a consensus opinion classification for each ECG based on American Heart Association's 2018 Expert Consensus criteria. The most ischemic OH ECG classification was compared with the last ED ECG classification. RESULTS: From 7/27/12 to 7/18/19, 176 patients were entered with a mean age of 61.2 ± 16.6 years; 102/176 (58%) were male. Overall, 504 OH and ED 12-lead ECGs were acquired (2.9 ECGs/patient). ECG classification inter-rater reliability kappa score was 0.63 ± 0.02 (substantial agreement). Overall, 86/176 (49%) changed ECG classification from the OH to ED setting; 69/86 (80%) of these ECGs changed from more to less ischemic classifications. Of 49 OH STEMI ECG classifications, 33/49 (67%) changed to a less ischemic (non-STEMI) ED ECG classification. CONCLUSIONS: Change in 12-lead ECG classification from OH to ED setting in patients resuscitated from OHCA was common (49%). The OH STEMI classification changed to a less ischemic (non-STEMI) ED classification in 67% of cases.

Multi-Task Multi-Domain Learning for Digital Staining and Classification of Leukocytes.

This paper addresses digital staining and classification of the unstained white blood cell images obtained with a differential contrast microscope. We have data coming from multiple domains that are partially labeled and partially matching across the domains. Using unstained images removes time-consuming staining procedures and could facilitate and automatize comprehensive diagnostics. To this aim, we propose a method that translates unstained images to realistically looking stained images preserving the inter-cellular structures, crucial for the medical experts to perform classification. We achieve better structure preservation by adding auxiliary tasks of segmentation and direct reconstruction. Segmentation enforces that the network learns to generate correct nucleus and cytoplasm shape, while direct reconstruction enforces reliable translation between the matching images across domains. Besides, we build a robust domain agnostic latent space by injecting the target domain label directly to the generator, i.e., bypassing the encoder. It allows the encoder to extract features independently of the target domain and enables an automated domain invariant classification of the white blood cells. We validated our method on a large dataset composed of leukocytes of 24 patients, achieving state-of-the-art performance on both digital staining and classification tasks.

SLC37A4-CDG: Mislocalization of the glucose-6-phosphate transporter to the Golgi causes a new congenital disorder of glycosylation.

Loss-of-function of the glucose-6-phosphate transporter is caused by biallelic mutations in SLC37A4 and leads to glycogen storage disease Ib. Here we describe a second disease caused by a single dominant mutation in the same gene. The mutation abolishes the ER retention signal of the transporter and generates a weak Golgi retention signal. Intracellular mislocalization of the transporter leads to a congenital disorder of glycosylation instead of glycogen storage disease.

End tidal CO2 and cerebral oximetry for the prediction of return of spontaneous circulation during cardiopulmonary resuscitation.

BACKGROUND: End Tidal CO2 (ETCO2) is a reasonable predictor of Return of Spontaneous Circulation (ROSC) in cardiac arrest (CA), though with many limitations. Cerebral Oximetry (CerOx) non-invasively measures brain O2 saturation and correlates with flow. OBJECTIVES: This study compares ETCO2 and CerOx for ROSC prediction during both out of hospital (OHCA) and emergency department cardiac arrests (EDCA). METHODS: We conducted a prospective study on CA patients resuscitated in the ED. ETCO2 and CerOx simultaneously measured during ED CPR. Data was analyzed with logistic regression modeling and area under the curve (AUC). RESULTS: 176 patients were analyzed, 66.7% were witnessed, 52.8% had bystander CPR. EMS alert to ED arrival was 27.0 ± 10.6 min. Initial rhythm was 31.8% asystole, 27.8% PEA, 25.6% VF/VT with 26.1% achieving ROSC. AUC predictors of ROSC were: last 5 min trend [CerOx = 0.82 ; ETCO2 = 0.74], delta first to last [CerOx = 0.86 ; ETCO2 = 0.73], the penultimate minute [CerOx = 0.81 ; ETCO2 = 0.76], and final minute [CerOx = 0.89 ; ETCO2 = 0.77]. AUC comparison of simultaneous measurements (n = 125) revealed: last 5 min trend [CerOx = 0.80 ; ETCO2 = 0.79], delta first to last [CerOx = 0.83 ; ETCO2 = 0.75], penultimate minute [CerOx = 0.83 ETCO2 = 0.74], and final minute [CerOx = 0.89 ; ETCO2 = 0.75]. CONCLUSIONS: Our data shows, both ETCO2 and rSO2 are good predictors of ROSC. We found CerOx superior to ETCO2 in predicting ROSC.

Enabling SDN in VANETs: What is the Impact on Security?

The demand for safe and secure journeys over roads and highways has been growing at a tremendous pace over recent decades. At the same time, the smart city paradigm has emerged to improve citizens' quality of life by developing the smart mobility concept. Vehicular Ad hoc NETworks (VANETs) are widely recognized to be instrumental in realizing such concept, by enabling appealing safety and infotainment services. Such networks come with their own set of challenges, which range from managing high node mobility to securing data and user privacy. The Software Defined Networking (SDN) paradigm has been identified as a suitable solution for dealing with the dynamic network environment, the increased number of connected devices, and the heterogeneity of applications. While some preliminary investigations have been already conducted to check the applicability of the SDN paradigm to VANETs, and its presumed benefits for managing resources and mobility, it is still unclear what impact SDN will have on security and privacy. Security is a relevant issue in VANETs, because of the impact that threats can have on drivers' behavior and quality of life. This paper opens a discussion on the security threats that future SDN-enabled VANETs will have to face, and investigates how SDN could be beneficial in building new countermeasures. The analysis is conducted in real use cases (smart parking, smart grid of electric vehicles, platooning, and emergency services), which are expected to be among the vehicular applications that will most benefit from introducing an SDN architecture.

The cervical vertebrae maturation (CVM) method cannot predict craniofacial growth in girls with Class II malocclusion.

INTRODUCTION: The cervical vertebrae maturation (CVM) method is used to determine the timing of treatment of Class II malocclusion. Because its performance has not been tested in patients with Class II, the objective of this study was to evaluate the effectiveness of the CVM method in predicting craniofacial growth in Class II malocclusion. METHODS: Twenty-nine untreated girls with Class II malocclusion were identified among participants of the Nijmegen Growth Study. Each girl had a series of cephalograms taken semi-annually from 9 to 14 years of age. The CVM status was established by five observers on a cephalogram taken at 9 years; mandibular and maxillary length and anterior face height were assessed on all available cephalograms. Method error was evaluated with kappa statistics and Bland-Altman (BA) plots. Regression analysis was used to determine if CVM grade can predict the amount of facial growth. RESULTS: The mean kappa for intra-rater agreement during grading with CVM was 0.36 (fair agreement). BA plots demonstrated acceptable agreement for cephalometric measurements. The regression analysis demonstrated that the only chronologic age was associated with the facial growth. The largest effect of age was for condylion-gnathion (Cd-Gn) and articulare-gnathion (Ar-Gn)-for every additional 6 months the Cd-Gn increases by 1.8mm [95 per cent confidence interval (CI): 1.7, 1.9, P < 0.001] and Ar-Gn increases by 1.59mm (95 per cent CI: 1.52, 1.67, P < 0.001). The CVM grade could not predict the change of cephalometric variables. CONCLUSIONS: There is no evidence to support the hypothesis that the CVM method can predict the amount of craniofacial growth in girls with Class II malocclusion.

3ß,5α,6ß-Cholestanetriol and 25-hydroxycholesterol accumulate in ATP-binding cassette transporter G1 (ABCG1)-deficiency.

OBJECTIVE: Oxysterols are oxidized derivatives of sterols that have cytotoxic effects and are potent regulators of diverse cellular functions. Efficient oxysterol removal by the sub-family G member 1 of the ATP-binding cassette transporters (ABCG1) is essential for cell survival and control of cellular processes. However, the specific role of ABCG1 in the transport of various oxysterol species has been not systematically investigated to date. Here, we examined the involvement of ABCG1 in the oxysterol metabolism by studying oxysterol tissue levels in a mouse model of Abcg1-deficiency. METHODS AND RESULTS: Analysis of lung tissue of Abcg1(-/-) mice on a standard diet revealed that 3ß,5α,6ß-cholestanetriol (CT) and 25-hydroxycholesterol (HC) accumulated at more than 100-fold higher levels in comparison to wild-type mice. 24S-HC and 27-HC levels were also elevated, but were minor constituents. A radiolabeled assay employing regulable ABCG1-expressing HeLa cell lines revealed that 25-HC export to albumin was dependent on functional ABCG1 expression and could be blocked by an excess of unlabeled 25-HC or 27-HC. In this cell line, 25-HC at low doses triggered mitochondrial membrane potential, and reactive oxygen species production, which are both indirect indicators of cellular energy expenditure. CONCLUSION: Our results suggest that 25-HC and CT are physiologic substrates for ABCG1. Excessive accumulation of these oxysterols may explain the increased rate of cell death and the inflammatory phenotype observed in Abcg1-deficient animals and cells.

SR-PSOX at sites predisposed to atherosclerotic lesion formation mediates monocyte-endothelial cell adhesion.

OBJECTIVE: The scavenger receptor SR-PSOX/CXCL16, which is identical to the chemokine CXCL16, is thought to be involved in atherogenesis. However, the presence and function of SR-PSOX/CXCL16 in the endothelium of atherosclerotic arteries has not been substantiated. METHODS AND RESULTS: In rabbit aorta immunocytochemistry revealed SR-PSOX/CXCL16 primarily in the endothelium at sites predisposed to lesion formation, in the endothelium of early atherosclerotic lesions, and mainly in intimal macrophages of more developed lesions, indicating that SR-PSOX/CXCL16-expression shifts during atherogenesis. In addition to its function as scavenger receptor and chemokine, SR-PSOX mediated the adhesion of THP-1 monocytes to endothelial cells in vitro. Both THP-1 monocytes and endothelial cells express SR-PSOX/CXCL16, and THP-1 monocytes express CXCR6, the specific receptor for SR-PSOX/CXCL16. Anti-SR-PSOX/CXCL16 and anti-CXCR6 antibody block monocyte adhesion, showing that SR-PSOX/CXCL16-CXCR6 interaction mediates monocyte-endothelial cell adhesion. SR-PSOX/CXCL16 expression of endothelial cells is upregulated by pro-inflammatory cytokines, and is reversed by incubation with ciglitazone and lovastatin. CONCLUSIONS: We suggest that SR-PSOX/CXCL16 may promote the adhesion of monocytes to the endothelium during early atherogenesis and that accumulating cytokines enhance SR-PSOX/CXCL16-mediated adhesion by upregulating SR-PSOX/CXCL16 expression. Manipulation of SR-PSOX/CXCL16 expression with anti-inflammatory agents may be of therapeutic value.

Apolipoprotein E induces antiinflammatory phenotype in macrophages.

OBJECTIVE: Apolipoprotein E (apoE) exerts potent antiinflammatory effects. Here, we investigated the effect of apoE on the functional phenotype of macrophages. METHODS AND RESULTS: Human apoE receptors very-low-density lipoprotein receptor (VLDL-R) and apoE receptor-2 (apoER2) were stably expressed in RAW264.7 mouse macrophages. In these cells, apoE downregulated markers of the proinflammatory M1 phenotype (inducible nitric oxide synthase, interleukin [IL]-12, macrophage inflammatory protein-1α) but upregulated markers of the antiinflammatory M2 phenotype (arginase I, SOCS3, IL-1 receptor antagonist [IL-1RA]). In addition, M1 macrophage responses (migration, generation of reactive oxygen species, antibody-dependent cell cytotoxicity, phagocytosis), as well as poly(I:C)- or interferon-γ-induced production of proinflammatory cytokines; cyclooxygenase-2 expression; and activation of nuclear factor-κB, IκB, and STAT1, were suppressed in VLDL-R- or apoER2-expressing cells. Conversely, the suppression of the M2 phenotype and the enhanced response to poly(I:C) were observed in apoE-producing bone marrow macrophages derived from VLDL-R-deficient mice but not wild-type or low-density lipoprotein receptor-deficient mice. The modulatory effects of apoE on macrophage polarization were inhibited in apoE receptor-expressing RAW264.7 cells exposed to SB220025, a p38 mitogen-activated protein kinase inhibitor, and PP1, a tyrosine kinase inhibitor. Accordingly, apoE induced tyrosine kinase-dependent activation of p38 mitogen-activated protein kinase in VLDL-R- or apoER2-expressing macrophages. Under in vivo conditions, apoE-/- mice transplanted with apoE-producing wild-type bone marrow showed increased plasma IL-1RA levels, and peritoneal macrophages of transplanted animals were shifted to the M2 phenotype (increased IL-1RA production and CD206 expression). CONCLUSIONS: ApoE signaling via VLDL-R or apoER2 promotes macrophage conversion from the proinflammatory M1 to the antiinflammatory M2 phenotype. This effect may represent a novel antiinflammatory activity of apoE.

The ARF-like GTPase ARFRP1 is essential for lipid droplet growth and is involved in the regulation of lipolysis.

ADP-ribosylation factor (ARF)-related protein 1 (ARFRP1) is a GTPase regulating protein trafficking between intracellular organelles. Here we show that mice lacking Arfrp1 in adipocytes (Arfrp1(ad-/-)) are lipodystrophic due to a defective lipid droplet formation in adipose cells. Ratios of mono-, di-, and triacylglycerol, as well as the fatty acid composition of triglycerides, were unaltered. Lipid droplets of brown adipocytes of Arfrp1(ad-/-) mice were considerably smaller and exhibited ultrastructural alterations, such as a disturbed interaction of small lipid-loaded particles with the larger droplets, suggesting that ARFRP1 mediates the transfer of newly formed small lipid particles to the large storage droplets. SNAP23 (synaptosomal-associated protein of 23 kDa) associated with small lipid droplets of control adipocytes but was located predominantly in the cytosol of Arfrp1(ad-/-) adipocytes, suggesting that lipid droplet growth is defective in Arfrp1(ad-/-) mice. In addition, levels of phosphorylated hormone-sensitive lipase (HSL) were elevated, and association of adipocyte triglyceride lipase (ATGL) with lipid droplets was enhanced in brown adipose tissue from Arfrp1(ad-/-) mice. Accordingly, basal lipolysis was increased after knockdown of Arfrp1 in 3T3-L1 adipocytes. The data indicate that disruption of ARFRP1 prevents the normal enlargement of lipid droplets and produces an activation of lipolysis.

Biomechanical evaluation of knotless anatomical double-layer double-row rotator cuff repair: a comparative ex vivo study.

BACKGROUND: The layered configuration of the rotator cuff tendon is not taken into account in classic rotator cuff tendon repair techniques. HYPOTHESIS: The mechanical properties of (1) the classic double-row technique, (2) a double-layer double-row (DLDR) technique in simple suture configuration, and (3) a DLDR technique in mattress suture configuration are significantly different. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-four sheep shoulders were assigned to 3 repair groups of full-thickness infraspinatus tears: group 1, traditional double-row repair; group 2, DLDR anchor repair with simple suture configuration; and group 3, DLDR knotless repair with mattress suture configuration. After ultrasound evaluation of the repair, each specimen was cyclically loaded with 10 to 100 N for 50 cycles. Each specimen was then loaded to failure at a rate of 1 mm/s. RESULTS: There were no statistically significant differences among the 3 testing groups for the mean footprint area. The cyclic loading test revealed no significant difference among the 3 groups with regard to elongation. For the load-to-failure test, groups 2 and 3 showed no differences in ultimate tensile load when compared with group 1. However, when compared to group 2, group 3 was found to have significantly higher values regarding ultimate load, ultimate elongation, and energy absorbed. CONCLUSION: The DLDR fixation techniques may provide strength of initial repair comparable with that of commonly used double-row techniques. When compared with the knotless technique with mattress sutures, simple suture configuration of DLDR repair may be too weak. Knotless DLDR rotator cuff repair may (1) restore the footprint by the use of double-row principles and (2) enable restoration of the shape and profile. CLINICAL RELEVANCE: Double-layer double-row fixation in mattress suture configuration has initial fixation strength comparable with that of the classic double-row fixation and so may potentially improve functional results of rotator cuff repair.

Arthroscopic reduction and subchondral support of reverse Hill-Sachs lesions with a bioabsorbable interference screw.

Traumatic posterior dislocation of the shoulder is frequently associated with an osteochondral defect on the anterior articular surface of the humeral head (so-called reverse Hill-Sachs lesion). Possible treatment options are either filling or elevation of the osseous defect. Previously, an open technique has been described using a bioabsorbable interference screw. On the basis of a 64-year-old patient presenting with a reverse Hill-Sachs lesion after epileptic seizure, we describe an arthroscopic technique in which the defect is reconstructed under arthroscopic and fluoroscopic control and supported by a bioabsorbable interference screw.

Knotless anatomic double-layer double-row rotator cuff repair: a novel technique re-establishing footprint and shape of full-thickness tears.

The standard technique for restoring footprint after full-thickness tears of the rotator cuff includes double-row or transosseous-equivalent techniques. However, the anatomically typical bird's beak shape and profile of tendon insertion may not be originally restored and biomechanics may be altered. In this report, the authors describe a technique that involves creating two intratendinous stitches at different levels of the torn tendon. The first passes through the bursal-side layer, the second stitch through the joint-side layer. Both stitches may be performed in mattress suture configuration. The anchorage is performed by knotless anchors in order to avoid knots lying within the insertion area. The footprint is restored first medially then laterally by the use of double-row principles. The joint-side suture is anchored within the medially placed anchor. The bursal-side suture is anchored by a laterally placed anchor. The anatomic insertion and restoration of the shape and profile may be enabled by the described double-layer suture technique. Using a double-layer double-row repair may potentially improve functional results of rotator cuff repair constructs.

The surgical approach for locking plate osteosynthesis of displaced proximal humeral fractures influences the functional outcome.

This study evaluated the influence of the surgical approach for locking plate osteosynthesis in proximal humeral fractures during a 1-year period. We performed a comparative study in 83 patients to evaluate possible benefits for an early functional result for function, pain, activity levels, radiographic evaluation, and complications. In 39 cases, the extended anterolateral deltoid-splitting approach was used (group DS); in 44 cases, the deltopectoral approach was used (group DP). The clinical and radiologic follow-up took place 3, 6, and 12 months after the operation. The functional results in the adjusted Constant score after 3 months showed higher values for group DS of 57.9% vs group DP with 49.6%. After 6 months, no significant differences were seen, with 69.4% for group DS and 71.4% for group DP. Finally, after 12 months, group DP showed higher results at 81% compared with 73.1% for DS. In the subgroups of the Constant score, abduction and active anterior elevation showed particularly higher values in group DP. The duration of the operation was 67 minutes in group DS and 86 minutes in group DP. One case of avascular necrosis was observed in group DS and 3 in group DP. We conclude that the choice of approach for exposure of the proximal humerus region may influence the functional outcome. Stable osteosynthesis is important, but the outcome of operatively treated proximal humerus fractures is dependent on soft tissue management as well.

Infiltration of the pes anserinus complex by an extraarticular diffuse-type giant cell tumor (D-TGCT).

This report describes the case of a 26-year-old woman with a recurrent extraarticular diffuse-type tenosynovial giant cell tumor (D-TGCT) of the medial region of the knee affecting the pes anserinus and hamstring tendons. Presurgical MRI did not exclude infiltrative properties of the tumor. In the histological evaluation, the tumor showed an aggressive dispersion by infiltrating the collagenous tissue of the hamstring tendons. The treatment included a resection of the pes anserinus complex with distal semitendinosus and gracilis tendons. Regarding extraarticular D-TGCT a review of the literature showed a predominant affection of the medial region of the knee and thigh.

The use of hamstrings in anterior cruciate ligament reconstruction in patients over 40 years.

INTRODUCTION: Anterior cruciate ligament reconstruction is an increasingly established method even in patients over 40 years old. Recent studies with regard to this procedure used BTB transplants. We did a retrospective follow-up examination on over-40-year-old patients with anterior cruciate ligament reconstruction using hamstring transplants and compared them to a younger control group. Our hypothesis is that functional outcome after ACL-reconstruction is comparable in patients under and over 40 years of age. MATERIALS AND METHODS: Retrospective follow-up examinations in 28 patients, 11 women and 17 men. The average age at the time of operation was 43.5 years (range 40-61). The average follow-up period was 30.4 months. Half of the patients had a femoral fixation in TransFix technique (Arthrex, Naples, USA), while the other 14 patients had a femoral bioscrew fixation (Arthrex, Naples, USA). Objectivity was ensured by measurements of anterior tibial translation with the rolimeter (Aircast). The functional outcome was determined by clinical scores (Tegner activity scale, Lysholm knee score, OAK score and IKDC score). The degree of arthrosis was defined on the basis of tunnelview radiographs and compared to the non-operated site. Functional results and degree of laxity was compared to a sex matched control group (mean age 28.0). RESULTS: The median values for the Lysholm knee score were 91.5 points (range 69-100), for the OAK score 93.5 points (range 67-100) and for the IKDC score 83.35 points (range 62.1-100). For the Tegner activity scale values of 4.5 points (range 3-8) were obtained. In the IKDC knee examination form we found normal and nearly normal values in 86% and in the OAK examination score good and very good results in 82%. Ninety-three percent had an AP side-to-side difference of <5 mm in the operated knee. Subjectively, 75% reported that they had no feeling of instability, even when practising sport. No significant correlation between functional outcome and patients' age was present. Furthermore there were no significant differences between the investigated and the younger control group. The most advanced signs of arthrosis were found in the medial compartment of the operated side (degree A: 36%; degree B: 46%; degree C: 14%; degree D: 4%). CONCLUSION: The predominantly good results and a high level of patient satisfaction show that anterior cruciate ligament reconstruction is justified even in over-40-year-old patients with persistend subjective symptomatic anterior knee instability. The indication for reconstruction should be based on individual factors such as level of activity or subjective feeling of instability rather than on a dogmatic age limit. Advanced arthrotic changes compared to the healthy side, might be due to a too long period of preoperative decision making.

Expression of ATP binding cassette-transporter ABCG1 prevents cell death by transporting cytotoxic 7beta-hydroxycholesterol.

Oxysterols result from cholesterol by enzymatic or oxidative processes. Some exert cytotoxic effects leading to necrosis or apoptosis. Detoxification of these compounds mainly occurs in the liver and requires transport from peripheral tissues towards it. Some ATP-binding cassette transporters are involved in export of cytotoxic compounds. In the current study, we investigated whether ABC transporter family member G1 (ABCG1) may be involved in oxysterol transport, since its gene expression is highly responsive to oxysterol loading. TetOff HeLa cells stably expressing ABCG1 showed decreased mass uptake of 7beta-hydroxycholesterol (7beta-HC) whereas that of other physiologically relevant oxysterols was unaffected. Application of 7beta-HC to ABCG1 expressing cells induced hyperpolarization of mitochondrial membrane potential and production of reactive oxygen species, indicating energy consumption by the ATP-binding cassette transporter when it is activated by its correct substrate. Our study points to detoxification as one of potential cellular functions of ABCG1. We assume that ABCG1 protects against 7beta-HC-induced cell death, an important role in prevention of neurodegenerative and cardiovascular disease.