SK channels and the varieties of slow after-hyperpolarizations in neurons

Action potentials and associated Ca2+ influx can be followed by slow after-hyperpolarizations (sAHPs) caused by a voltage-insensitive, Ca2+-dependent K+ current. Slow AHPs are a widespread phenomenon in mammalian (including human) neurons and are present in both peripheral and central nervous systems. Although, the molecular identity of ion channels responsible for common membrane potential mechanisms has been largely determined, the nature of the channels that underlie the sAHPs in neurons, both in the brain and in the periphery, remains unresolved. This short review discusses why there is no clear molecular candidate for sAHPs.     

Pathways of removal of free DNA vector ends in normal and DNA-PKcs-deficient SCID mouse hepatocytes transduced with rAAV vectors

Elucidation of the mechanisms of transformation of single-stranded (ss) recombinant adeno-associated virus (rAAV) vector genomes into a variety of stable double-stranded (ds) forms is key to a complete understanding of rAAV vector transduction in vivo. Ds monomer genome formation and cellular ds DNA break (DSB) repair pathways that remove free vector ends toxic to cells, presumably play a central role in this process. By delivering rAAV and naked ds linear DNA vectors into livers of DNA-dependent protein kinase catalytic subunit (DNA-PKcs)-deficient severe combined immunodeficiency (SCID) and wild-type mice, we demonstrate the presence of three major pathways for free ds vector end removal: (1) DNA-PKcs-dependent self-circularization, (2) DNA-PKcs-independent self-circularization, and (3) DNA-PKcs-independent concatemerization. By using the DNA-PKcs-independent pathways, mouse hepatocytes efficiently removed free ds rAAV vector ends even in the absence of DNA-PKcs. Our studies suggest a hierarchical organization of these processes; self-circularization is the preferred pathway over concatemerization, although the former has a limited capacity to remove free vector ends. These studies shed new light on the molecular mechanisms of rAAV vector transduction in vivo.     

Differential effects of saturated and monounsaturated fats on postprandial lipemia and glucagon-like peptide 1 responses in patients with type 2 diabetes

BACKGROUND: Postprandial lipemia is important in the development of coronary artery disease because of elevated postprandial triacylglycerol-rich plasma lipoproteins and suppressed HDL-cholesterol concentrations. We showed in healthy subjects a possible association between postprandial lipid metabolism and the responses of the duodenal incretin hormones glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide after meals rich in saturated and monounsaturated fatty acids (oleic acid), respectively. OBJECTIVE: The objective was to compare the postprandial responses (8 h) of glucose, insulin, fatty acids, triacylglycerol, gastric inhibitory polypeptide, and GLP-1 to saturated- and monounsaturated-rich test meals. DESIGN: Twelve overweight patients with type 2 diabetes ingested 3 meals randomly: an energy-free soup with 50 g carbohydrate (control meal), the control meal plus 100 g butter, and the control meal plus 80 g olive oil. Triacylglycerol responses were measured in total plasma and in a chylomicron-rich and a chylomicron-poor fraction. RESULTS: No significant differences in the glucose, insulin, or fatty acid responses to the 2 fat-rich meals were seen. The plasma triacylglycerol and chylomicron triacylglycerol responses were highest after the butter meal. HDL-cholesterol concentrations decreased significantly after the butter meal but did not change significantly after the olive oil meal. GLP-1 responses were highest after the olive oil meal. CONCLUSIONS: Olive oil induced lower triacylglycerol concentrations and higher HDL-cholesterol concentrations than did butter, without eliciting significant changes in glucose, insulin, or fatty acids. Furthermore, olive oil induced higher concentrations of GLP-1, which may indicate a relation between fatty acid composition, incretin responses, and triacylglycerol metabolism postprandially in patients with type 2 diabetes.     

Liposomes to target the lymphatics by subcutaneous administration

Liposomes have been proposed as carriers for the delivery of therapeutic and diagnostic agents to the lymphatic system. Subcutaneous (s.c.) injection is the route of administration most extensively studied for this purpose. Decisive factors influencing lymphatic absorption and lymph node uptake of s.c. administered liposomes are liposome size and the anatomical site of injection. Generally, other factors such as lipid composition, charge and the presence of a hydrophilic PEG-coating on the liposome surface do not substantially affect lymphatic absorption and lymph node uptake of s.c. administered liposomes. Studies on the intranodal fate of liposomes demonstrate that phagocytosis by macrophages is the most important mechanism for lymph node uptake of liposomes. The observation of relatively high uptake of liposomes in regional lymph nodes after s.c. administration has stimulated research on lymphatic targeting of liposomes for diagnostic and therapeutic applications.     

Therapeutic efficacy of liposomal gentamicin in clinically relevant rat models

Sterically stabilized liposomes are able to localize selectively at sites of infection, potentially permitting targeted drug delivery. Up to now, the majority of studies investigating therapeutic efficacy of liposomes have been conducted in animals with an intact host defense infected with high antibiotic-susceptible bacteria. In the present study, the therapeutic efficacy of gentamicin encapsulated in sterically stabilized liposomes, alone or in combination with the free drug was studied in rats with intact host defense as well as leukopenic rats. Rats were inoculated with a high gentamicin-susceptible or low-gentamicin susceptible Klebsiella pneumoniae in the left lung, resulting in an acute unilateral pneumonia. Survival rates demonstrate the valuable therapeutic properties of the liposome-encapsulated drug in these clinically relevant animal models.     

Lipid-coated polyplexes for targeted gene delivery to ovarian carcinoma cells

A nonviral gene delivery vector has been developed in our laboratory based on the cationic polymer, poly(2-(dimethylethylamino)ethyl methacrylate) (p(DMAEMA)). p(DMAEMA)-based polyplexes have been successfully used for the transfection of OVCAR-3 cells in vitro. However, these polyplexes were unable to transfect OVCAR-3 cells growing in the peritoneal cavity of nude mice after intraperitoneal administration, which could be ascribed to inactivation by components (including hyaluronic acid) present in the tumor ascitic fluid. The present work aimed at (a) protecting p(DMAEMA)-based polyplexes against destabilization or inactivation by polyanions such as hyaluronic acid present in tumor ascitic fluid and (b) enhancing cellular uptake of the protected p(DMAEMA)-based polyplexes by targeting with antibody Fab' fragments. To fulfill these requirements, we have developed a detergent removal method to coat polyplexes with anionic lipids. With this method, spherical particles of approximately 125 nm, which were protected from destabilization by polyanions, were obtained. More importantly, the transfection efficiency of lipopolyplexes was unaffected in the presence of hyaluronic acid, indicating that lipid coating of polyplexes protects against destabilization by hyaluronic acid. By conjugating antibody Fab' fragments directed against the epithelial glycoprotein-2 to the lipidic surface of these lipopolyplexes, target cell-specific transfection of OVCAR-3 cells could be obtained in vitro.     

Verapamil and risk of cancer in patients with coronary artery disease. DAVIT Study Group. Danish Verapamil Infarction Trial

The risk of cancer in users of verapamil was assessed in a long-term follow-up of 1,775 patients who were randomized to verapamil or matching placebo in the Danish Verapamil Infarction Trial-II in the years 1985 to 1987. During 10,474 patient-years, no increased risk of cancer was observed for the verapamil-treated men or women compared with the age- and sex-matched background population.     

Effects and Clinical Significance of GII.4 Sydney Norovirus,United States, 2012–2013

During 2012, global detection of a new norovirus (NoV) strain, GII.4 Sydney, raised concerns about its potential effect in the United States. We analyzed data from NoV outbreaks in 5 states and emergency department visits for gastrointestinal illness in 1 state during the 2012–13 season and compared the data with those of previous seasons. During August 2012–April 2013, a total of 637 NoV outbreaks were reported compared with 536 and 432 in 2011–2012 and 2010–2011 during the same period. The proportion of outbreaks attributed to GII.4 Sydney increased from 8% in September 2012 to 82% in March 2013. The increase in emergency department visits for gastrointestinal illness during the 2012–13 season was similar to that of previous seasons. GII.4 Sydney has become the predominant US NoV outbreak strain during the 2012–13 season, but its emergence did not cause outbreak activity to substantially increase from that of previous seasons.     

Seromukotympanon bei Neugeborenen mit Down-Syndrom

Hintergrund: Bei mehr als der H?lfte der Kinder mit Down-Syndrom tritt eine H?rst?rung auf. Als h?ufigste Ursache gelten chronische bzw. rezidivierende Paukenergüsse (Seromukotympanon), die mit einer H?ufigkeit von etwa 60% beobachtet werden.