Der Weg vom Heterogenen Immunoassay zum Immunosensor: Prinzipien und Applikationen im Bereich der Klinischen Chemie

Immunosensoren sind ligandenaffinitäts-messende Sensoren, bei denen immunochemische Reaktionen über eine Transducerschaltung aufgezeichnet werden. Das fundamentale Merkmal aller Immunosensoren ist hierbei die Spezifität von Antikörpern zu geeigneten Analyten unter Ausbildung eines stabilen Immunkomplexes. Dies ist auch die Basis der Immunoassay-Methodologie. Im Vergleich beider Methoden ermöglicht die Transducer-Tech-nologie eine markierungsfreie Detektion und zugleich eine Quantifizierung des gebildeten Immunkomplexes. In den letzten Jahren wurden Immunoassays auch verstärkt zur Spurenanalyse von toxischen Substanzen in der pharmazeutischen und der Nahrungsmittelindustrie sowie in der Umweltanalytik eingesetzt. Entsprechende Mess-ungen können hierbei jedoch nur diskontinuierlich erfolgen. Um eine kontinuierliche Analytik zu ermöglichen, er-scheint der Einsatz von Immunosensoren besonders vielversprechend. Auch im Bereich der klinischen Diagnostik gibt es viele Anwendungsgebiete, für die ein kontinuierliches „Monitoring“ von verschiedenen Analyten von großem Nutzen wäre. Deshalb sollten gerade Labormediziner die Vorteile des Einsatzes von Immunosensoren in der klinische Diagnostik und Laboratoriumsmedizin bedenken. Dieser Vortrag wendet sich somit vor allem an Klinische Chemiker, Biochemiker, Physiker und Ingenieure mit Schwerpunkt Immunoassayentwicklung und Biosensortechnologie. Ziel des Vortrags ist es, die Entwicklungen in den Bereichen Immunoassay und Immunosensoren zusammenfassend darzulegen und auf das enorme Potential,wie auch auf das konkurrenzstarke Umfeld der Immunosensortechnologie in der klinischen Diagnostik hinzuweisen

Publicações de teatro em 2013

O texto procede ao levantamento bibliográfico, selecção da tipologia e listagem das edições de / sobre teatro no ano indicado, inclui adenda aos anos anterioresinfo:eu-repo/semantics/publishedVersio

Selective Attenuation of Norepinephrine Release and Stress-Induced Heart Rate Increase by Partial Adenosine A1 Agonism

The release of the neurotransmitter norepinephrine (NE) is modulated by presynaptic adenosine receptors. In the present study we investigated the effect of a partial activation of this feedback mechanism. We hypothesized that partial agonism would have differential effects on NE release in isolated hearts as well as on heart rate in vivo depending on the genetic background and baseline sympathetic activity. In isolated perfused hearts of Wistar and Spontaneously Hypertensive Rats (SHR), NE release was induced by electrical stimulation under control conditions (S1), and with capadenoson 6 · 10−8 M (30 µg/l), 6 · 10−7 M (300 µg/l) or 2-chloro-N6-cyclopentyladenosine (CCPA) 10−6 M (S2). Under control conditions (S1), NE release was significantly higher in SHR hearts compared to Wistar (766+/−87 pmol/g vs. 173+/−18 pmol/g, p<0.01). Capadenoson led to a concentration-dependent decrease of the stimulation–induced NE release in SHR (S2/S1 = 0.90±0.08 with capadenoson 6 · 10−8 M, 0.54±0.02 with 6 · 10−7 M), but not in Wistar hearts (S2/S1 = 1.05±0.12 with 6 · 10−8 M, 1.03±0.09 with 6 · 10−7 M). CCPA reduced NE release to a similar degree in hearts from both strains. In vivo capadenoson did not alter resting heart rate in Wistar rats or SHR. Restraint stress induced a significantly greater increase of heart rate in SHR than in Wistar rats. Capadenoson blunted this stress-induced tachycardia by 45% in SHR, but not in Wistar rats. Using a [35S]GTPγS assay we demonstrated that capadenoson is a partial agonist compared to the full agonist CCPA (74+/−2% A1-receptor stimulation). These results suggest that partial adenosine A1-agonism dampens stress-induced tachycardia selectively in rats susceptible to strong increases in sympathetic activity, most likely due to a presynaptic attenuation of NE release

Hyaluronan Export through Plasma Membranes Depends on Concurrent K+ Efflux by Kir Channels

Hyaluronan is synthesized within the cytoplasm and exported into the extracellular matrix through the cell membrane of fibroblasts by the MRP5 transporter. In order to meet the law of electroneutrality, a cation is required to neutralize the emerging negative hyaluronan charges. As we previously observed an inhibiting of hyaluronan export by inhibitors of K+ channels, hyaluronan export was now analysed by simultaneously measuring membrane potential in the presence of drugs. This was done by both hyaluronan import into inside-out vesicles and by inhibition with antisense siRNA. Hyaluronan export from fibroblast was particularly inhibited by glibenclamide, ropivacain and BaCl2 which all belong to ATP-sensitive inwardly-rectifying Kir channel inhibitors. Import of hyaluronan into vesicles was activated by 150 mM KCl and this activation was abolished by ATP. siRNA for the K+ channels Kir3.4 and Kir6.2 inhibited hyaluronan export. Collectively, these results indicated that hyaluronan export depends on concurrent K+ efflux

Evaluation of the sensitivity and specificity of a novel line immunoassay for the detection of criteria and non-criteria antiphospholipid antibodies in comparison to established ELISAs.

BackgroundPersistent antiphospholipid antibodies (aPL) constitute the serological hallmark of the antiphospholipid syndrome (APS). Recently, various new assay technologies for the detection of aPL better suited to multiplex reaction environments than ELISAs emerged. We evaluated the diagnostic performance of such a novel line immunoassay (LIA) for the simultaneous detection of 10 different aPL.MethodsFifty-three APS patients and 34 healthy controls were investigated for criteria (antibodies against cardiolipin [aCL], β2-glycoprotein I [aβ2-GPI]) and non-criteria aPL (antibodies against phosphatidic acid [aPA], phosphatidyl-choline [aPC], -ethanolamine [aPE], -glycerol [aPG], -inositol [aPI], -serine [aPS], annexin V [aAnnV], prothrombin [aPT]) IgG and IgM by LIA. Criteria aPL were additionally determined with the established Alegria (ALE), AcuStar (ACU), UniCap (UNI), and AESKULISA (AES) systems and non-criteria aPL with the AES system. Diagnostic performance was evaluated with a gold standard for criteria aPL derived from the results of the four established assays via latent class analysis and with the clinical diagnosis as gold standard for non-criteria aPL.ResultsAssay performance of the LIA for criteria aPL was comparable to that of ALE, ACU, UNI, and AES. For non-criteria aPL, sensitivities of the LIA for aPA-, aPI-, aPS-IgG and aPA-IgM were significantly higher and for aPC-, aPE-, aAnnV-IgG and aPC- and aPE-IgM significantly lower than AES. Specificities did not differ significantly.ConclusionsThe LIA constitutes a valuable diagnostic tool for aPL profiling. It offers increased sensitivity for the detection of aPL against anionic phospholipids. In contrast, ELISAs exhibit strengths for the sensitive detection of aPL against neutral phospholipids

Renal and circulatory effects of large volume plasma expansion in patients with hepatorenal syndrome type 1(◆)(◆) This work was financed by departmental funds. No grants were received. Wolfgang Huber is a member of the medical advisory board of Pulsion medical Systems, Munich, Germany.The other authors declare no conflict of interest.

Introduction. Hepatorenal syndrome type I (HRS I) may be a consequence of circulatory dysfunction in cirrhotic patients with portal hypertension. This uncontrolled interventional pilot study examines the hemodynamic and renal effects of large volume plasma expansion in HRS I.Material and methods. 14 cirrhotic patients (8 m, 6 f, age 60 (58-65) years) with HRS I received large volume plasma expansion with up to 400 mL of 20% human albumin solution per 12 over 48 h under hemodynamic monitoring by transpulmonary thermodilution. Creatinine clearances (ClCreat) were calculated for 12-h periods. Plasma expansion was withheld if criteria of volume overload [Extravascular lung Water Index (ELWI) > 9 mL/kg or Global End-Dias-tolic Volume Index (GEDI) > 820 mL/m2] were met. Paracentesis was performed according to clinical necessity and treatment continued for 48 h thereafter. Serum creatinine values were observed for 12 days.Results. Patients received 1.6 (1.5-2.0) g of albumin per kg bodyweight and day for 48 to 96 h. During the treatment period, GEDVI [724 (643-751) mL/m2 vs. 565 (488-719) mL/m2; p = 0.001], cardiac index (CI) [4.9 (4.1-6.15) L/min/m2 vs. 3.9 (3.4-5.0) L /min/m2; p = 0.033], urinary output [25 (17-69) mL/h vs. 17 (8-39) mL/h; p = 0.016) and ClCreat [20 (15-47) vs. 12 (6-17); p = 0.006] increased whereas systemic vascular resistance index (SVRI), plasma renin activity (PRA) and plasma aldosterone were significantly reduced. At 48 h there were two complete responses (serum creatinine < 133 umol/L) and on day 12, 8 patients had a complete response.Conclusion. HRS I may respond to large volume plasma expansion with or without paracentesis