Solute diffusion is hindered in the mitochondrial matrix

Intracellular chemical reactions generally constitute reaction-diffusion systems located inside nanostructured compartments like the cytosol, nucleus, endoplasmic reticulum, Golgi, and mitochondrion. Understanding the properties of such systems requires quantitative information about solute diffusion. Here we present a novel approach that allows determination of the solvent-dependent solute diffusion constant (D(solvent)) inside cell compartments with an experimentally quantifiable nanostructure. In essence, our method consists of the matching of synthetic fluorescence recovery after photobleaching (FRAP) curves, generated by a mathematical model with a realistic nanostructure, and experimental FRAP data. As a proof of principle, we assessed D(solvent) of a monomeric fluorescent protein (AcGFP1) and its tandem fusion (AcGFP1(2)) in the mitochondrial matrix of HEK293 cells. Our results demonstrate that diffusion of both proteins is substantially slowed by barriers in the mitochondrial matrix (cristae), suggesting that cells can control the dynamics of biochemical reactions in this compartment by modifying its nanostructure.     

Combined suicide and cytokine gene therapy for peritoneal carcinomatosis

BACKGROUND: Gene therapy is a novel approach for the treatment of cancers, and tumours disseminated in the peritoneal cavity are suitable for in situ delivery of a therapeutic gene. AIMS: The efficacy of a therapy combining a suicide gene (herpes simplex virus type I thymidine kinase (HSV-TK)) and cytokine genes was investigated in a model of peritoneal carcinomatosis induced by colon carcinoma cells in syngeneic rats. MATERIAL AND METHODS: Pre-established macroscopic tumours in BDIX rats were treated by intraperitoneal injections of retrovirus producing cells (FLYA13 TK, FLYA13 granulocyte macrophage-colony stimulating factor (GM-CSF), FLYA13 interleukin 12 (IL-12)) and ganciclovir (GCV). RESULTS: TK/GCV treated animals showed a slight increase in survival time (72 days) compared with the control group (63 days) while the association of cytokine and TK/GCV gene therapy resulted in significantly improved survival, with a large proportion of animals remaining tumour free on day 480 (60% and 40% for TK/GCV/GM-CSF and TK/GCV/IL-12 treated animals, respectively). Histological analysis of treated animals showed that the remaining tumour nodes were infiltrated by mononuclear cells but no major differences were observed between the various treatments. Immunohistochemical analysis revealed that lymphoid CD4(+) and CD8(+) T cells as well as macrophages accumulated outside untreated tumour nodes while CD8(+) and CD25(+) activated T cells and macrophages heavily infiltrated the tumours after the different treatments. CONCLUSIONS: Our data indicate that combined suicide and cytokine gene therapy is a powerful approach for the treatment of macroscopic peritoneal carcinomatosis.     

Kommentar zu den Leitlinien der Europ?ischen Gesellschaft für Kardiologie (ESC) zur Diagnostik und Therapie des akuten Koronarsyndroms ohne persistierende ST-Streckenhebung

Non-ST-elevation acute coronary syndromes (NSTE-ACS) comprise a wide spectrum of disease severities and mortality risks. Next to establishing the diagnosis, clinical management therefore also requires risk stratification in order to adequately select the intensity and urgency of further work-up and treatment. In September 2011 updated recommendations for the management of patients with NSTE-ACS were published by the European Society of Cardiology. Major innovations included the use of highly sensitive troponin assays, including the resulting possibility of establishing a fast-track protocol, the routine recommendation of echocardiography in all patients and the introduction of coronary computed tomography (CT) angiography as a possibility to rule out coronary disease in selected individuals. The importance of risk stratification is emphasized throughout the document and routine use of the GRACE risk score as well as the CRUSADE bleeding risk score is encouraged. The recommendations reflect the availability of new antithrombotic agents and new timelines for invasive work-up are introduced. This comment in German summarizes the ESC guidelines and highlights relevant amendments as compared to the previous version.     

Wire fractures in Solysafe septal occluders: a single center experience

Objectives : To determine the incidence of device fractures (DF) after implantation of a Solysafe® Septal Occluder (iSSO) and to assess the spectrum of associated problems. Background : In August 2010, after initial unpublished reports on DF, the manufacturer issued an “urgent field safety notice,” prompting all medical care providers to re‐examine all patients after iSSO. Methods : Prospective single center study. Extended follow‐up examination, including standardized fluoroscopy (sF), was performed in all patients after iSSO. Results : A total of 111 patients had undergone iSSO at our institution between June 2005 and July 2010. Median age and body weight were 50 years (9.3–79.6) and 75 kg (29–122), respectively. Indications for iSSO were (1) patent foramen ovale in patients with a history of cryptogenic stroke (n = 84; 76%) and (2) hemodynamically significant atrial septal defect of the secundum type (n = 27; 24%). A total of 113 devices were implanted. Complete follow‐up was available in 103 patients (92.8%). Median follow‐up was 1.9 years (0–5.2). There were no postimplantation neurological events or symptoms. The closure rate was 97.1%. DF was suspected on a chest X‐ray in one patient and documented in 10 patients by sF. The overall probability of freedom from DF was 82.3% after 5 years. One patient had embolization of a device fragment to the right pulmonary artery. So far, all patients with DF have been managed conservatively. Conclusions : The incidence of DF after iSSO is unacceptably high. sF is imperative for accurate diagnosis of DF. Further, follow‐up is needed to determine the risk of clinical complications and to optimize management. © 2012 Wiley Periodicals, Inc.     

Coronary artery bypass grafting using two different anesthetic techniques: Part 3: Adrenergic responses.

Twenty patients were studied during and after coronary artery bypass grafting (CABG). The patients were randomly assigned to two groups. In 10 patients, intraoperative general anesthesia (GA) was based on a combination of intravenous (IV) sufentanil and midazolam. In 10 other patients, thoracic epidural analgesia (TEA) with 0.375% bupivacaine plus sufentanil, 1:200,000 (5 micrograms/mL), and intraoperative GA with midazolam/N2O were used. During the prebypass period, lower heart rates (HR), less variability in mean arterial pressure (MAP), and systemic vascular resistance (SVR) was accompanied by less variability in plasma norepinephrine (NE) concentrations in the TEA group. Although no differences were observed between the groups in perfusion pressure and the amount of vasoactive drugs used during the bypass period, variability in SVR was less in the TEA group. This was accompanied by less increase in NE and less variability in epinephrine (E) plasma concentrations. However, cortisol (Co) release was higher during this period in the TEA group. Weaning from bypass was accompanied by higher MAP and SVR in the TEA group at a lower HR, whereas no differences were observed in the E, NE, and Co plasma concentrations between the groups. During the first and second postoperative days, better pain relief and lower E and Co plasma concentrations were found in the TEA group. It can be concluded that better hemodynamic stability during the prebypass and bypass periods was accompanied by less E and NE release during these periods. Co release in the TEA group was higher during the bypass period. Weaning from bypass was characterized by better hemodynamics in the TEA group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coronary artery bypass grafting using two different anesthetic techniques: Part 2: Postoperative outcome.

The aim of the present investigation was to study the effects of intraoperative and postoperative epidural pain management during and after coronary artery bypass grafting (CABG) on the recovery time, postoperative pulmonary and cardiac parameters, visual analog scale (VAS) scores, and sedation scores (SS) compared with patients anesthetized with general anesthesia (GA) whose postoperative pain was relieved with intermittent intravenous (IV) administration of nicomorphine. Fifty-four patients were studied postoperatively after uncomplicated CABG. In the thoracic epidural analgesia (TEA) group (n = 27), intraoperative analgesia was based on high TEA in combination with GA. In the GA group (n = 27), IV anesthesia with high-dose sufentanil and midazolam was used. Postoperative pain management in the GA group consisted of intermittent IV administration of nicomorphine, 0.1 mg/kg every 6 hours, whereas for the TEA group continuous high TEA with 0.125% bupivacaine plus sufentanil, 1:1,000,000 (0.05 mL/cm body length/hr) was used. Patients in the TEA group awakened earlier (148 [34] minutes vs 335 [51] minutes), resumed spontaneous respiration earlier (326 [79] minutes vs 982 [52] minutes), and were extubated earlier (463 [79] minutes vs 1140 [58] minutes). VAS score, SS, and postoperative PaO2 were significantly (P less than or equal to 0.01) better in the TEA group. The incidence of tachycardia (15 vs 2 patients) and postoperative myocardial ischemia (12 vs 4 patients) was higher in the GA group. It is concluded that intraoperative and postoperative pain treatment with epidurally administered bupivacaine plus sufentanil improved the recovery time, as well as pulmonary and cardiac outcome after CABG, when compared with IV postoperative pain treatment after intraoperative GA with sufentanil and midazolam.