The specific inhibition of the cardiac electrogenic sodium/bicarbonate cotransporter leads to cardiac hypertrophy.

Two alkalinizing mechanisms coexist in cardiac myocytes to maintain intracellular pH: sodium/bicarbonate cotransporter (electroneutral isoform NBCn1 and electrogenic isoform NBCe1) and sodium/proton exchanger (NHE1). Dysfunction of these transporters has previously been reported to be responsible for the development of cardiovascular diseases. The aim of this study was to evaluate the contribution of the downregulation of the NBCe1 to the development of cardiac hypertrophy. To specifically reduce NBCe1 expression, we cloned shRNA into a cardiotropic adeno-associated vector (AAV9-shNBCe1). After 28 days of being injected with AAV9-shNBCe1, the expression and the activity of NBCe1 in the rat heart were reduced. Strikingly, downregulation of NBCe1 causes significant hypertrophic heart growth, lengthening of the action potential in isolated myocytes, an increase in the duration of the QT interval and an increase in the frequency of Ca2+ waves without any significant changes in Ca2+ transients. An increased compensatory expression of NBCn1 and NHE1 was also observed. We conclude that reduction of NBCe1 is sufficient to induce cardiac hypertrophy and modify the electrical features of the rat heart.

Elimination of factor VIII-specific B cells by immunotoxins composed of a single factor VIII domain fused to Pseudomonas exotoxin A.

Essentials There is still a need for novel therapeutic approaches for hemophilia A patients with inhibitors. A factor VIII domain was used as the targeting moiety for elimination of FVIII-specific B cells. The immunodominant C2 domain was fused to exotoxin A from Pseudomonas aeruginosa (hC2-ETA). Murine C2 domain-specific B cells were selectively and efficiently eliminated by hC2-ETA ex vivo. SUMMARY: Background Today, the most serious complication for patients with hemophilia A undergoing factor VIII (FVIII) replacement therapy is the development of neutralizing antibodies (inhibitors). Although inhibitors can be eradicated by application of high doses of FVIII, the immune tolerance induction therapy fails in up to 30% of patients. Hence, there is still an urgent need for novel therapeutic approaches for patients with persisting inhibitors. Objectives In the present study, the potential use of immunotoxins containing exotoxin A (ETA) from Pseudomonas aeruginosa for selective elimination of FVIII-specific B cells was explored. Methods The immunodominant C2 domain of human FVIII was used as a targeting moiety instead of the full-length FVIII protein and the resulting human C2 domain-ETA fusion protein (hC2-ETA) was produced in Escherichia coli. Results Binding studies with monoclonal C2 domain-specific antibodies confirmed the conformational integrity of the C2 domain in hC2-ETA. The functionality of hC2-ETA was tested ex vivo by incubation of splenocytes from inhibitor-positive FVIII knockout mice with hC2-ETA and controls. FVIII-specific memory B cells from splenocytes were differentiated by FVIII stimulation in antibody-secreting cells (ASC) and detected by an enzyme-linked immunospot assay. Although the controls showed no effect, incubation of splenocytes with hC2-ETA reduced the number of C2-specific ASC in a dose-dependent fashion, indicating specific and efficient elimination of C2-specific memory B cells. Conclusions Overall, the results of the study support the fact that FVIII domain immunotoxins might be a potential new tool for the elimination of FVIII-specific B cells in patients with hemophilia A and persisting inhibitors.

Anti-factor VIII antibodies in brothers with haemophilia A share similar characteristics.

INTRODUCTION: The development of neutralizing antibodies (inhibitors) against coagulation factor VIII (FVIII) is currently the most serious complication for patients with haemophilia A undergoing FVIII replacement therapy. Several genetic factors have been acknowledged as risk factors for inhibitor development. AIM: To analyze the influence of genetic factors on the nature of the humoral immune response to FVIII in eight brother pairs with inhibitors. METHODS: The domain specificity of FVIII-specific IgG was analysed by antibody binding to FVIII fragments and homologue-scanning mutagenesis (HSM). The FVIII-specific IgG subclasses were measured by direct ELISA. RESULTS: Of the 16 patient analysed with both methods, 12 had A2- and 13 had C2-specific IgG. The presence of A1-, A3- or C1-specific IgG was identified in nine of 14 patients analysed by HSM. IgG1, IgG2 and IgG4 subclasses contributed to the anti-FVIII IgG response, and the amount of FVIII-specific IgG1 (r = 0.66) and IgG4 (r = 0.69) correlated significantly with inhibitor titres. Patients with high concentrations of total anti-FVIII IgG (r = 0.69) or high inhibitor titres (r = 0.52) had a high proportion of FVIII-specific IgG4. Statistical analysis revealed trends/evidence that the subclass distribution (P = 0.0847) and domain specificity to HC/LC (P = 0.0883) and A2/C2 (P = 0.0011) of anti-FVIII IgG were more similar in brothers compared to unrelated subjects. CONCLUSION: Overall, our data provide a first hint that anti-FVIII IgG characteristics are comparable among haemophilic brothers with inhibitors. Whether genetic factors also influence the nature of patients' antibodies needs to be confirmed in a larger study population.

Selection and characterisation of FVIII-specific single chain variable fragments.

The development of inhibitory anti-FVIII antibodies is currently the most severe complication in the treatment of haemophilia A patients. Inhibitor eradication can be achieved by immune tolerance induction (ITI). Recent findings suggest a correlation between the FVIII-specific IgG subclass distribution and the duration or outcome of ITI. To quantify FVIII-specific IgG subclasses in patients' plasma FVIII-specific IgG standards are required. Here, the isolation of FVIII-specific single chain variable fragments (scFvs) from synthetic phage display libraries and the characterisation of their FVIII domain specificity are described. The isolated scFv 1G10, which binds to the FVIII A2 domain, was cloned into the context of the four human IgG (hIgG) subclasses and expressed in mammalian cells. Purified 1G10-hIgG1, -hIgG2, -hIgG3 and -hIgG4 are used as standards to determine the absolute amounts and relative contribution of the different FVIII-specific IgG subclasses in future studies. The results from these studies will eventually add to understanding the role of the FVIII-specific IgG subclass distribution as prognostic factor for the outcome of ITI.

Probing Anderson localization of light via decay rate statistics.

We have studied the distribution of resonance widths P(Gamma) in one-, two-, and three-dimensional multiple light scattering systems. P(Gamma) should follow a universal power law P(Gamma) approximately Gamma(-1) in the localized regime as confirmed by extensive numerical calculations. This behavior can be interpreted as an unambiguous signature of exponential Anderson localization of light in open systems.

The top ten pitfalls in managed care contracts.

Managed care contracts may contain clauses that either have no purpose or have a purpose that the provider does not fully understand. Such clauses may go unrecognized by providers until they are invoked by payers during a contract dispute, often to the detriment of providers. Providers should attempt to exclude or modify such clauses. Providers also should define basic concepts, such as identifying the terms of the contract, determining how disputes might arise over these terms, documenting the agreement struck with the payer, selecting an appropriate dispute-resolution mechanism, and developing a strategy for speedy dispute resolution.

[Effect of arterio-venous fistula blood flow dynamics on ECG abnormalities in chronic hemodialysis patients]. / Wplyw dynamiki przeplywu przetoki tetniczo-zylnej na zmiany elektrokardiograficzne u chorych hemodializowanych z powodu krancowej niewydolnosci nerek.

UNLABELLED: The dialysis doses is mostly dependent on well functional permanent vascular access. From the other hand high vascular access blood flow (Qva) may induce cardiac problems in HD patients. The purpose of this study was to investigate the effect of vascular access dynamics on electrocardiographic abnormalities in hemodialysis patients. Therefore, forty non-diabetic, HD patients, with native vascular access (VA) were divided into two equal groups; with Qva > 1500 ml/min (group A), and also Qva < 1500 ml/min (group B). The average of VA survival period was 28 +/- 18 (mean +/- SE) (group A), and 29 +/- 15 (months) (group B). The Qva measurements monitoring by color Doppler sonography included also: maximal velocity (Vmax), time average of maximal velocity (TAMX), pulsate index (PI), and resistive index (RI). Kt/V index was calculated, as classical parameter of adequacy, and also shunt recirculation using 3 urea samples was measured. For estimation of cardiac function we used M-mode echocardiography, and 24-hours ECG (Holter) monitoring. The occurrence of ventricular (VE), and supraventricular extrasystoles (SVE), ST-T, and ST characteristic as well were monitored by 24-hours Holter. CONCLUSIONS: 1. In the group with high Qva (A) we observed significantly higher number of VE, and also of SVE recorded by Holter monitoring compared with the low Qva group (B). 2. The mean number of patients with ST-T changes was higher in group A (12 vs. 7), but number of patients with recorded by Holter ST depression, and ST elevation between investigated groups were similar. 3. The mean number of ventricular arrhythmias of Lown classified as 4A, and 4B of Lown grading was significantly higher in the group with high Qva (A).

[The recurrent laryngeal nerve paralysis as a complication after thyroid surgery]. / Porazenie nerwu krtaniowego wstecznego jako powiklanie operacji tarczycy.

The authors have presented results of otolaryngologic and phoniatric examination of 504 patients after thyroid surgery. 39 patients (7.74%) with recurrent laryngeal nerve paralysis were qualified for thorough phoniatric investigation.

[Videolaryngostroboscopy of the larynx in patients after thyroid surgery]. / Obraz wideolaryngostroboskopowy krtani u chorych po operacji tarczycy.

The authors have presented the video of different stroboscopic pictures of the larynx in patients after thyroid gland surgery.