Role of the Glycine Receptor ß Subunit in Synaptic Localization and Pathogenicity in Severe Startle Disease.

Startle disease is due to the disruption of recurrent inhibition in the spinal cord. Most common causes are genetic variants in genes (GLRA1, GLRB) encoding inhibitory glycine receptor (GlyR) subunits. The adult GlyR is a heteropentameric complex composed of α1 and ß subunits that localizes at postsynaptic sites and replaces embryonically expressed GlyRα2 homomers. The human GlyR variants of GLRA1 and GLRB, dominant and recessive, have been intensively studied in vitro. However, the role of unaffected GlyRß, essential for synaptic GlyR localization, in the presence of mutated GlyRα1 in vivo is not fully understood. Here, we used knock-in mice expressing endogenous mEos4b-tagged GlyRß that were crossed with mouse Glra1 startle disease mutants. We explored the role of GlyRß under disease conditions in mice carrying a missense mutation (shaky) or resulting from the loss of GlyRα1 (oscillator). Interestingly, synaptic targeting of GlyRß was largely unaffected in both mouse mutants. While synaptic morphology appears unaltered in shaky animals, synapses were notably smaller in homozygous oscillator animals. Hence, GlyRß enables transport of functionally impaired GlyRα1 missense variants to synaptic sites in shaky animals, which has an impact on the efficacy of possible compensatory mechanisms. The observed enhanced GlyRα2 expression in oscillator animals points to a compensation by other GlyRα subunits. However, trafficking of GlyRα2ß complexes to synaptic sites remains functionally insufficient, and homozygous oscillator mice still die at 3 weeks after birth. Thus, both functional and structural deficits can affect glycinergic neurotransmission in severe startle disease, eliciting different compensatory mechanisms in vivo.

Direct 3D-Bioprinting of hiPSC-Derived Cardiomyocytes to Generate Functional Cardiac Tissues.

3D-bioprinting is a promising technology to produce human tissues as drug screening tool or for organ repair. However, direct printing of living cells has proven difficult. Here, a method is presented to directly 3D-bioprint human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes embedded in a collagen-hyaluronic acid ink, generating centimeter-sized functional ring- and ventricle-shaped cardiac tissues in an accurate and reproducible manner. The printed tissues contain hiPSC-derived cardiomyocytes with well-organized sarcomeres and exhibit spontaneous and regular contractions, which persist for several months and are able to contract against passive resistance. Importantly, beating frequencies of the printed cardiac tissues can be modulated by pharmacological stimulation. This approach opens up new possibilities for generating complex functional cardiac tissues as models for advanced drug screening or as tissue grafts for organ repair or replacement.

Super-resolution imaging pinpoints the periodic ultrastructure at the human node of Ranvier and its disruption in patients with polyneuropathy.

The node of Ranvier is the key element in saltatory conduction along myelinated axons, but its specific protein organization remains elusive in the human species. To shed light on nanoscale anatomy of the human node of Ranvier in health and disease, we assessed human nerve biopsies of patients with polyneuropathy by super-resolution fluorescence microscopy. We applied direct stochastic optical reconstruction microscopy (dSTORM) and supported our data by high-content confocal imaging combined with deep learning-based analysis. As a result, we revealed a âˆ¼ 190 nm periodic protein arrangement of cytoskeletal proteins and axoglial cell adhesion molecules in human peripheral nerves. In patients with polyneuropathy, periodic distances increased at the paranodal region of the node of Ranvier, both at the axonal cytoskeleton and at the axoglial junction. In-depth image analysis revealed a partial loss of proteins of the axoglial complex (Caspr-1, neurofascin-155) in combination with detachment from the cytoskeletal anchor protein ß2-spectrin. High content analysis showed that such paranodal disorganization occurred especially in acute and severe axonal neuropathy with ongoing Wallerian degeneration and related cytoskeletal damage. We provide nanoscale and protein-specific evidence for the prominent, but vulnerable role of the node of Ranvier for axonal integrity. Furthermore, we show that super-resolution imaging can identify, quantify and map elongated periodic protein distances and protein interaction in histopathological tissue samples. We thus introduce a promising tool for further translational applications of super resolution microscopy.

A mock circulation loop to test extracorporeal CO2 elimination setups.

BACKGROUND: Extracorporeal carbon dioxide removal (ECCO2R) is a promising yet limited researched therapy for hypercapnic respiratory failure in acute respiratory distress syndrome and exacerbated chronic obstructive pulmonary disease. Herein, we describe a new mock circuit that enables experimental ECCO2R research without animal models. In a second step, we use this model to investigate three experimental scenarios of ECCO2R: (I) the influence of hemoglobin concentration on CO2 removal. (II) a potentially portable ECCO2R that uses air instead of oxygen, (III) a low-flow ECCO2R that achieves effective CO2 clearance by recirculation and acidification of the limited blood volume of a small dual lumen cannula (such as a dialysis catheter). RESULTS: With the presented ECCO2R mock, CO2 removal rates comparable to previous studies were obtained. The mock works with either fresh porcine blood or diluted expired human packed red blood cells. However, fresh porcine blood was preferred because of better handling and availability. In the second step of this work, hemoglobin concentration was identified as an important factor for CO2 removal. In the second scenario, an air-driven ECCO2R setup showed only a slightly lower CO2 wash-out than the same setup with pure oxygen as sweep gas. In the last scenario, the low-flow ECCO2R, the blood flow at the test membrane lung was successfully raised with a recirculation channel without the need to increase cannula flow. Low recirculation ratios resulted in increased efficiency, while high recirculation ratios caused slightly reduced CO2 removal rates. Acidification of the CO2 depleted blood in the recirculation channel caused an increase in CO2 removal rate. CONCLUSIONS: We demonstrate a simple and cost effective, yet powerful, "in-vitro" ECCO2R model that can be used as an alternative to animal experiments for many research scenarios. Moreover, in our approach parameters such as hemoglobin level can be modified more easily than in animal models.

Foam formation in biogas plants caused by anaerobic digestion of sugar beet.

The use of sugar beet in anaerobic digestion (AD) during biogas production can lead to process upsets such as excessive foaming in fermenters. In the present study, foam formation in sugar beet-fed digestates was studied in foaming tests. The increasing disintegration grade of sugar beet was observed to have a promoting effect on foaming in the digestate but did not affect the biogas yield. Chemical analysis of foam and digestate from sugar beet silage AD showed high concentrations of pectin, other carbohydrates and N-containing substances in the foam. Both pectin and sucrose showed little foaming in AD. Nevertheless, sucrose and calcium chloride had a promoting effect on foaming for pectin AD. Salts of divalent ions also enhanced the foam intensity in the case of sugar beet silage AD, whereas ammonium chloride and urea had a lessening effect on sugar beet-based foaming.

Prognostic factors for remission of and survival in acquired hemophilia A (AHA): results from the GTH-AH 01/2010 study.

Acquired hemophilia A (AHA) is caused by autoantibodies against factor VIII (FVIII). Immunosuppressive treatment (IST) results in remission of disease in 60% to 80% of patients over a period of days to months. IST is associated with frequent adverse events, including infections as a leading cause of death. Predictors of time to remission could help guide IST intensity but have not been established. We analyzed prognostic factors in 102 prospectively enrolled patients treated with a uniform IST protocol. Partial remission (PR; defined as no active bleeding, FVIII restored >50 IU/dL, hemostatic treatment stopped >24 hours) was achieved by 83% of patients after a median of 31 days (range 7-362). Patients with baseline FVIII <1 IU/dL achieved PR less often and later (77%, 43 days) than patients with ≥1 IU/dL (89%, 24 days). After adjustment for other baseline characteristics, low FVIII remained associated with a lower rate of PR (hazard ratio 0.52, 95% confidence interval 0.33-0.81, P < .01). In contrast, PR achieved on steroids alone within ≤21 days was more common in patients with FVIII ≥1 IU/dL and inhibitor concentration <20 BU/mL (odds ratio 11.2, P < .0001). Low FVIII was also associated with a lower rate of complete remission and decreased survival. In conclusion, presenting FVIII and inhibitor concentration are potentially useful to tailor IST in AHA.

Desmoplakin and KIF20B as target antigens in patients with paroxysmal nocturnal haemoglobinuria.

At least two hypotheses have been proposed to explain the mechanism of clonal expansion of mutant cells in paroxysmal nocturnal haemoglobinuria (PNH). One hypothesis assumes an immune escape mechanism and another proposes an intrinsic second mutational event within clonal cells. We hypothesised that autoantibodies detected in PNH patients could identify antigens that might play a role in the pathophysiology of this disease and screened a human fetal liver cDNA library for serological reactivity against haematopoietic stem/progenitor cells antigens using the SEREX approach. Two antigens were identified that are constitutively expressed in CD34(+) cells. Three and four of 10 PNH patients showed antibody responses against kinesin family member 20B (KIF20B) (previously termed M-phase phosphoprotein 1, MPP1) and desmoplakin (DSP) respectively. We also found an antibody response in one of 20 healthy volunteers against desmoplakin, yet at a much lower titre than in PNH patients. No response to KIF20B or desmoplakin was detected in five patients with aplastic anaemia without a glycosyl phosphatidyl inositol -deficient clone. We conclude that KIF20B and desmoplakin have been shown to be the first known auto-antigens to be recognised by the immune system of patients with PNH. The analysis of the mechanisms underlying the autoimmune response might contribute to our understanding of the clonal expansion in PNH.

Activation of platelets and fibrinolysis induced by saturated air dives.

INTRODUCTION: The Doppler technique is currently the usual method for detection of bubbles in the circulation following decompression. However, cases of decompression sickness (DCS) frequently occur in the absence of detectable bubbles, so that other markers for increasing risk of DCS would be welcome. This study assessed the hemostatic effects of compressed-air saturation dives that conformed to the "safe" limits of accepted decompression tables. METHODS: We measured coagulation times, thrombin generation, platelets, and fibrinolysis in 21 male divers who were subjected to saturated hyperbaric exposures to 0.28-0.3 MPa (corresponds to 18-20 msw). Each diver did one dive. RESULTS: Pooled before- and after-dive data for all exposures showed after decompression, statistically significant changes included decrease of the mean platelet count after, increased induced platelet aggregation and number of platelet aggregates, increased number of P-selectin (CD62P) positive platelets and CD62P density on platelets, increase of platelet derived microparticles in the blood of the divers, decrease of factor XII, X, and fibrinogen concentrations, and marked increase of plasmin-antiplasmin complex concentration. Thrombin activation markers and coagulation times did not change significantly. CONCLUSIONS: Saturated hyperbaric exposures followed by nominally safe decompression led to activation of platelets and the fibrinolytic system. The probable mechanism for the activation of platelets and fibrinolysis is contact with the surface of evolved bubbles in the divers' circulation.

New molecular defects in the gamma subdomain of fibrinogen D-domain in four cases of (hypo)dysfibrinogenemia: fibrinogen variants Hannover VI, Homburg VII, Stuttgart and Suhl.

Four new molecular abnormalities in the gamma subdomain of the D domain elucidated in three unrelated thrombophilic patients and in one asymptomatic case of hypofibrinogenemia are reported: fibrinogen Suhl, gamma 326, Cys-->Tyr, fibrinogen Hannover VI, gamma 336 Met-->Ile, fibrinogen Stuttgart, gamma 345, Asn-->Asp and fibrinogen Homburg VII, gamma 354,Tyr-->Cys. In all cases, fibrin polymerization in plasma is impaired. In the case of fibrinogen Suhl, there was a normalization of fibrin polymerization in plasma at higher Ca(2+) concentration. The protective effect of Ca(2+) on plasmic degradation of fibrinogen was incomplete with all three variants. The fibrinogen molecules in variants Homburg VII and Suhl contain covalently bound albumin. Fibrin clot structure was abnormal in case of variant Homburg VII, with finer and more branched fibers forming a less porous clot. Experimental data indicate possible effects of the molecular abnormalities on Ca(2+)-binding, D-E interaction and lateral association of protofibrils.

On the prophylactic and therapeutic use of danaparoid sodium (Orgaran) in patients with heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is a rare but dangerous complication of heparin prophylaxis or treatment. The present laboratory tests to measure heparin-associated antibodies are not specific. The diagnosis of HIT mainly depends on the decrease in platelet count and on clinical symptoms. To evaluate clinical outcome, bleeding complications and platelet counts were evaluated in 45 patients with HIT type II (HIT II) treated prophylactically (subcutaneous injections) or therapeutically (intravenous infusion) with danaparoid. Group I included 24 patients with HIT II without thromboembolic complications who received danaparoid twice daily subcutaneously (10 IU/kg) for a mean of 16 days. Group II included 21 patients with thromboembolic complications. They were treated with intravenous danaparoid (2.6 IU/kg/h +/- 1.1) for a mean of 17 days. During subcutaneous prophylaxis, mean anti-Xa levels of 0.2 U/mL and during intravenous treatment, mean anti-Xa levels of 0.4 U/mL were reached. No deaths, amputations, or serious bleeding complications occurred, and no new thromboses were observed in both patient groups. Treatment with danaparoid led to a fast normalization of the platelet counts. This normalization occurred earlier and the concentration of platelets was higher in patients treated with intravenous doses. Danaparoid with subsequent vitamin K-antagonist treatment effectively prevents thromboembolic complications in patients with HIT.

In vitro hemocompatibility testing of biomaterials according to the ISO 10993-4.

The development of synthetic materials, textured polymers and metals and their increasing use in medicine make research of biomaterials' hemocompatibility very relevant. Problems arise from the polymorphism and diversity of the different materials, the static and dynamic test models and the patients' individual biologic factors. First, methods, models, tests as well as preanalytical factors have to be standardized according to the current knowledge in medicine laid down in the ISO 10993 part 4. The routine controls used in clinical chemistry and hematology have to be performed. Information about normal ranges (mean value, standard deviation, 95% confidence interval) should be provided. Tests have to be performed within a minimal delay of usually 2 h since some properties of blood change rapidly following collection. Various conditions (depending on the wall shear rate) were simulated within the centrifugation system and a Chandler system. Qualities and aspects of hemocompatibility such as platelet activation, oxidative burst, hemolysis, fibrinolysis, fibrin formation, generation of thrombin, contact activation, and complement activation were analysed and the results were entered non-dimensionally into a non-dimensional score system, where 0 points stand for the best and 65 points for the worst evaluation. We found a good correlation between the total score and contact activation, thrombin generation and leukocyte activation in a low shear stress system and a good correlation between the total score and thrombin generation, hemolysis and platelet activation in the high shear stress system. Further on the effect of additives and sterilization procedures can be measured. The concepts presented underline the relevance/importance of an efficient diagnostic approach to hemocompatibility that takes account of clinical and socio-economic concerns.

[Tissue factor (TF) and inhibitor (TFPI) concentrations in patients with urinary tract tumors and haematological malignancies]. / Stezenie czynnika tkankowego i jego inhibitora u chorych na guzy ukladu moczowego i choroby rozrostowe ukladu krwiotwórczego.

The aim of study was to evaluate TF activity and TFPI concentration in patients with haematological malignancies and urinary tract tumors. TFPI concentration and activity and TF concentration were measured in 20 patients suffering from acute myeloblastic leukaemia (AML), 21 patients with chronic myelogenous leukaemia (CML), 17 patients with chronic lymphatic leukaemia (CLL), 16 patients with multiple myeloma (MM) and 65 healthy adults. TFPI and TF concentrations were measured also in patients with renal cell carcinoma (n = 12) and bladder cancer (n = 17) and patients with benign prostatic hyperplasia (BPH) (n = 15). Patients with AML, CML, CLL, and cancer revealed elevated TFPI concentrations. Patients with AML, CML, CLL, MM showed decreased TFPI activity. However TFPI concentration correlated inversely with TFPI activity only in the AML group. No significant changes were observed in TF concentrations in all investigated groups.