Anatomy of coronary sinus ostium

Background: The coronary sinus is the main cardiac vein and it has become a clinically important structure especially through its role in providing access for different cardiac procedures. Materials and methods: The study was carried out on 100 randomly selected adult human cadaver hearts fixed in 10% formalin. The transverse and craniocaudal diameters of the coronary sinus ostium (CSO) were directly measured. The presence of the Thebesian valve was noted and the anatomical details of the valve were documented in each case in terms of the shape and extent of coverage of the CSO. Results: Considerable variations in the diameter of the CSO were observed. The mean craniocaudal diameter of the CSO was 8.1 ± 1.51 mm, and the mean transverse diameter was 7.67 ± 1.72 mm. Heart specimens without Thebesian valve tended to have larger ostia. The mean craniocaudal diameter and the mean transverse diameter of the CSO were statistically larger in the specimens without Thebesian valves (p = 0.000 and p = 0.001, respectively). Conclusions: The Thebesian valves were observed in 86 hearts, and a wide variety of their morphology was seen. The majority of the Thebesian valves were semilunar in shape (74.42%). The extent to which the valve covered the ostium was variable, including remnant valves that covered < 15% of the CSO (35%), and valves that were large and covered at least 75% of the CSO (22.09%). In 3 specimens the valve completely occluded the ostium.

Basilar artery fenestration

The posterior circulation of the brain constitutes the vertebrobasilar system and its branches, which are responsible for about 30% of the brain’s blood supply. The aim of this study was to describe the anomalies of the basilar artery, especially fenestrations. For that purpose, we examined 50 patients with computed tomography (CT) angiography during an 8-month period. In the CT reports of 2 (4%) patients of the 50 analysed, fenestration was found at the proximal basilar trunk. The two fenestrations in our series were not associated with aneurysms. No collateral branches originated from the two limbs of the fenestration. In conclusion, basilar artery fenestrations are a rare finding. The data derived from this study are useful teaching material for anatomists, and for the radiologists and neurosurgeons they are important for diagnostic and intervention procedures such as CT, magnetic resonance imaging, angiography, and surgical and endovascular procedures. (Folia Morphol 2011; 70, 2: 80–83

Engineering and functional immobilization of opioid receptors

Opioid receptors, like many G protein-coupled receptors (GPCRs), are notoriously unstable in detergents. We have now developed a more stable variant of the mu-opioid receptor (MOR) and also a method for the immobilization of solubilized, functional opioid receptors on a solid phase (magnetic beads). Starting with the intrinsically more stable kappa-opioid receptor (KOR), we optimized the conditions (i.e. detergents and stabilizing ligands) for receptor extraction from lipid bilayers of HEK293T cells to obtain maximal amounts of functional, immobilized receptor. After immobilization, the ligand binding profile remains the same as observed for the membrane-embedded receptor. For the immobilized wild-type mu-opioid receptor, however, no conditions were found under which ligand binding capacity was retained. To solve this problem, we engineered the receptor chimera KKM where the N-terminus and the first transmembrane helix (TM1) of wild-type MOR is exchanged for the homologous receptor parts of the wild-type KOR. This hybrid receptor behaves exactly as the wild-type MOR in functional assays. Interestingly, the modified MOR is expressed at six times higher levels than wild-type MOR and is similarly stable as wild-type KOR after immobilization. Hence the immobilized MOR, represented by the chimera KKM, is now also amenable for biophysical characterization. These results are encouraging for future stability engineering of GPCR

Morphologic characteristics of sacra associated with assimilation of the last lumbar vertebra

Background: The impact of lumbosacral transitional states on biomechanics of load transmission between the spine and the legs has been sporadically reported. The aims of the study were to identify morphostructural alterations of sacra associated with assimilation of the last lumbar vertebra and to analyse them in the light of their biomechanical impact. Materials and methods: Linear dimensions of sacrum, its body and base and articular surfaces were measured in 31 normal and 41 transitory sacra. Nineteen sacra presented articular and 22 osseous fusion of the last lumbar vertebra. Measured parameters were compared between normal sacra and the two variations of transitory sacra. Results: Sacra with articular fusion of the last lumbar vertebra showed more pronounced concavity of the sacral curvature and wider than long sacral bodies. The first sacral segment was modified, broaden, ventrally wider and elevated. Almost the whole segment bore at its sides auricular surfaces. Very small portion of the segment was non-articular with less pronounced wedging. Sacra with osseous fusion of the last lumbar vertebra showed similar concavity of the sacral curvature as normal sacra, but longer than wide sacral bodies. The ventral sloping half of the newly formed first segment bore auricular surfaces. The non-articular part was enlarged with pronounced wedging. Conclusions: The term “sacralisation“ includes both types of transitory sacra with mutually different morphostructural characteristics in contrast to the normal sacra. Analysis of these morphologic variations may help in understanding the different biomechanical properties and patterns of load transmissio

A ternary PEDOT-TiO2-reduced graphene oxide nanocomposite for supercapacitor applications

A ternary composite of PEDOT was prepared with TiO2 via emulsion polymerization method adjusting various weight ratios of TiO2 to PEDOT and synthesized rGO was then blended with this composite. The FTIR, UV–Vis and XRD analysis displayed characteristic features of PEDOT and TiO2. The morphology of the nano-hybrid structure was additionally investigated by SEM analysis. Pore size and surface area analysis of particles were characterized by BET method. The electrochemical analysis showed that the specific capacitance (Csp) for PEDOT-TiO2-15-rGO was 18.9 F.cm-2 at 0.1 mA g-1 current density

Annotation Error in Public Databases: Misannotation of Molecular Function in Enzyme Superfamilies

Due to the rapid release of new data from genome sequencing projects, the majority of protein sequences in public databases have not been experimentally characterized; rather, sequences are annotated using computational analysis. The level of misannotation and the types of misannotation in large public databases are currently unknown and have not been analyzed in depth. We have investigated the misannotation levels for molecular function in four public protein sequence databases (UniProtKB/Swiss-Prot, GenBank NR, UniProtKB/TrEMBL, and KEGG) for a model set of 37 enzyme families for which extensive experimental information is available. The manually curated database Swiss-Prot shows the lowest annotation error levels (close to 0% for most families); the two other protein sequence databases (GenBank NR and TrEMBL) and the protein sequences in the KEGG pathways database exhibit similar and surprisingly high levels of misannotation that average 5%–63% across the six superfamilies studied. For 10 of the 37 families examined, the level of misannotation in one or more of these databases is >80%. Examination of the NR database over time shows that misannotation has increased from 1993 to 2005. The types of misannotation that were found fall into several categories, most associated with “overprediction” of molecular function. These results suggest that misannotation in enzyme superfamilies containing multiple families that catalyze different reactions is a larger problem than has been recognized. Strategies are suggested for addressing some of the systematic problems contributing to these high levels of misannotation

Evolution of three human GPCRs for higher expression and stability

We recently developed a display method for the directed evolution of integral membrane proteins in the inner membrane of Escherichia coli for higher expression and stability. For the neurotensin receptor 1, a G-protein-coupled receptor (GPCR), we had evolved a mutant with a 10-fold increase in functional expression that largely retains wild-type binding and signaling properties and shows higher stability in detergent-solubilized form. We have now evolved three additional human GPCRs. Unmodified wild-type receptor cDNA was subjected to successive cycles of mutagenesis and fluorescence-activated cell sorting, and functional expression could be increased for all three GPCR targets. We also present a new stability screening method in a 96-well assay format to quickly identify evolved receptors showing increased thermal stability in detergent-solubilized form and rapidly evaluate them quantitatively. Combining the two methods turned out to be very powerful; even for the most challenging GPCR target-the tachykinin receptor NK(1), which is hardly expressed in E. coli and cannot be functionally solubilized-receptor mutants that are functionally expressed at 1 mg/l levels in E. coli and are stable in detergent solution could be quickly evolved. The improvements result from cumulative small changes in the receptor sequence. This combinatorial approach does not require preconceived notions for designing mutations. Our results suggest that this method is generally applicable to GPCRs. Existing roadblocks in structural and biophysical studies can now be removed by providing sufficient quantities of correctly folded and stable receptor protein

Engineering and functional immobilization of opioid receptors

Opioid receptors, like many G protein-coupled receptors (GPCRs), are notoriously unstable in detergents. We have now developed a more stable variant of the mu-opioid receptor (MOR) and also a method for the immobilization of solubilized, functional opioid receptors on a solid phase (magnetic beads). Starting with the intrinsically more stable kappa-opioid receptor (KOR), we optimized the conditions (i.e. detergents and stabilizing ligands) for receptor extraction from lipid bilayers of HEK293T cells to obtain maximal amounts of functional, immobilized receptor. After immobilization, the ligand binding profile remains the same as observed for the membrane-embedded receptor. For the immobilized wild-type mu-opioid receptor, however, no conditions were found under which ligand binding capacity was retained. To solve this problem, we engineered the receptor chimera KKM where the N-terminus and the first transmembrane helix (TM1) of wild-type MOR is exchanged for the homologous receptor parts of the wild-type KOR. This hybrid receptor behaves exactly as the wild-type MOR in functional assays. Interestingly, the modified MOR is expressed at six times higher levels than wild-type MOR and is similarly stable as wild-type KOR after immobilization. Hence the immobilized MOR, represented by the chimera KKM, is now also amenable for biophysical characterization. These results are encouraging for future stability engineering of GPCRs