Crosswire for recanalization of total occlusive coronary arteries

Coronary angioplasty of total occlusions is technically difficult and is associated with limited success rates. The procedural outcome is mainly determined by the underlying pathological process. Recanalization of total occlusions is aimed at finding the passage with least resistance, without causing dissection or perforation. Several techniques have been advocated to improve the overall success rate. Recently, a new 0.014" Nitinol wire (Crosswire, Terumo) has been introduced as a tool, to achieve higher success rates for total occlusion angioplasty. The wire consists of an extremely flexible Nitinol-core, a platinum/iridium coil at the distal tip, and a hydrophilic polymer coating. Balloon angioplasty was attempted in 30 totally occluded coronary arteries with mean age of occlusion being 5 +/- 4 months (range 2-14 months). The initial five procedures were performed following failure of the conventional angioplasty guidewires. Subsequently, Cross-wire was used electively in all the cases. The lesion was crossed successfully in 90% (27/30) cases. Dissection of the coronary artery with subintimal entry was seen in two (7%) cases, and the rest (three cases) could not be crossed. Balloon angioplasty and stenting (n = 21) were performed with good immediate angiographic results. There were no myocardial infarctions or deaths. Fourteen of 16 patients, who had completed 6 months follow-up, were asymptomatic. Angiographic evidence of in-stent restenosis was demonstrable in one case. Successful recanalization of total coronary occlusions by using Cross-wire can be expected in 83% cases, with reasonable safety.     

The pea (Pisum sativum L.) genes sym33 and sym40 control infection thread formation and root nodule function

Two novel non-allelic mutants that were unable to fix nitrogen (Fix ) were obtained after EMS (ethyl methyl sulfonate) mutagenesis of pea (Pisum sativum L.). Both mutants, SGEFix(-)-1) and SGEFix(-)-2, form two types of nodules: SGEFix(-)-1 forms numerous white and some pink nodules, while mutant SGEFix(-)-2 forms white nodules with a dark pit at the distal end and also some pinkish nodules. Both mutations are monogenic and recessive. In both lines the manifestation of the mutant phenotype is associated with the root genotype. White nodules of SGEFix(-)-1 are characterised by hypertrophied infection threads and infection droplets, mass endocytosis of bacteria, abnormal morphological differentiation of bacteroids, and premature degradation of nodule symbiotic structures. The structure of the pink nodules of SGEFix(-)-1 does not differ from that of the parental line, SGE. White nodules of SGEFix(-)-2 are characterised by "locked" infection threads surrounded with abnormally thick plant cell walls. In these nodules there is no endocytosis of bacteria into host-cell cytoplasm. The pinkish nodules of SGEFix(-)-2 are characterised by virtually undifferentiated bacteroids and premature degradation of nodule tissues. Thus, the novel pea symbiotic genes, synm40 and sym33, identified after complementation analysis in SGEFix(-)-1 and SGEFix(-)-2 lines, respectively, control early nodule developmental stages connected with infection thread formation and function.     

Plasticity of hippocampal corticosteroid receptors during aging in the rat

OBJECTIVE: The purpose of this study was to describe and validate an image-quality phantom to be used in dental radiography for comparison of film and digitally acquired images. STUDY DESIGN: An aluminum block of 12 steps, with 7 holes in each step, was covered by acrylic blocks. This phantom was radiographed with Kodak Ultra-speed and Ektaspeed Plus films at 70, 65, and 60 kVp with the whole exposure range available. All together, 50 dental films were randomly sequenced and presented to 7 observers. The average number of perceptible holes from all steps was plotted against exposure for each tube voltage and film type, generating a modified perceptibility curve. The tentative optimum exposure level was determined from perceptibility curves in each experimental condition and compared with that determined by means of the standard aluminum stepwedge and the preset time of the x-ray machine. The density range of this phantom at the optimum exposure was compared with that of clinical dental radiographs. Validity of the phantom was evaluated according to the optimum exposure level from the modified perceptibility curves and the overall density range. Finally, the average maximum numbers of perceptible holes at the tentative optimum exposure level were compared for each tube voltage and film type. The statistical test used was a 2-way factorial analysis of variance. RESULTS: The exposure at the perceptibility curve peak approximated that obtained by means of the standard aluminum step-wedge and the time preset by the manufacturer. The overall density range at the perceptibility curve peak covered the clinical density range for each tube voltage and film type. There were no statistically significant differences between film types or among tube voltages. CONCLUSIONS: The x-ray attenuation range for this phantom seemed to approximate clinical conditions. In addition, differences in image quality could be quantitatively evaluated by means of the number of the holes seen in the phantom.     

Voltage gating and permeation in a gap junction hemichannel

Gap junction channels are formed by members of the connexin gene family and mediate direct intercellular communication through linked hemichannels (connexons) from each of two adjacent cells. While for most connexins, the hemichannels appear to require an apposing hemichannel to open, macroscopic currents obtained from Xenopus oocytes expressing rat Cx46 suggested that some hemichannels can be readily opened by membrane depolarization [Paul, D. L., Ebihara, L., Takemoto, L. J., Swenson, K. I. & Goodenough, D. A. (1991), J. Cell Biol. 115, 1077-1089]. Here we demonstrate by single channel recording that hemichannels comprised of rat Cx46 exhibit complex voltage gating consistent with there being two distinct gating mechanisms. One mechanism partially closes Cx46 hemichannels from a fully open state, gammaopen, to a substate, gammasub, about one-third of the conductance of gammaopen; these transitions occur when the cell is depolarized to inside positive voltages, consistent with gating by transjunctional voltage in Cx46 gap junctions. The other gating mechanism closes Cx46 hemichannels to a fully closed state, gammaclosed, on hyperpolarization to inside negative voltages and has unusual characteristics; transitions between gammaclosed and gammaopen appear slow (10-20 ms), often involving several transient substates distinct from gammasub. The polarity of activation and kinetics of this latter form of gating indicate that it is the mechanism by which these hemichannels open in the cell surface membrane when unapposed by another hemichannel. Cx46 hemichannels display a substantial preference for cations over anions, yet have a large unitary conductance (approximately 300 pS) and a relatively large pore as inferred from permeability to tetraethylammonium (approximately 8.5 angstroms diameter). These hemichannels open at physiological voltages and could induce substantial cation fluxes in cells expressing Cx46.     

Synthesis and anti-inflammatory activity of some potential cyclic phenothiazines

Some new schiff's bases (IVa-IVe), thiazolidinones (Va-Ve), delta 2-triazolines (VIa-VIe) and formazans (VIIa-VIIe) of 2-chlorophenothiazine have been synthesized and screened against Carrageenin induced oedema in albino rats. Some compounds of the series have shown promising activity. The most active compound is 2-chloro-10[5-(2-fluorophenyl-2-oxo-4 thiazolidin-1-yl)-amino acetyl] phenothiazine was found to be most potent. This compound (Vb) was further evaluated in detail and compared with phenylbutazone for its relative anti inflammatory potency (ED50), ulcerogenic liabilities (UD50) and acute toxicity (ALD50). It was found to be almost comparable to phenylbutazone as regards anti-inflammatory activity was concerned but and minimum ulcerogenic liability and cardiovascular effects. Hence, it seems promising as an anti-inflammatory agent in our preliminary studies.     

The effect of the morphofunctional state of the thrombocytes on the activation of destabilization processes in patients with acute forms of ischemic heart disease

With the purpose of assessing the influence that platelet morphofunctional state may have on the degree of destabilization in patients with different forms of unstable angina we examined 198 patients using stress tests, Holter ECG monitoring, studying activation of thrombocytes with the aid of a luminescent-microscopy technique, and performing an analysis of aggregation. Important differences have been revealed in the studied parameters in those patients presenting with freshly detected and progressive stenocardia and with a developing, despite of the treatments administered, myocardial infarction, that might be caused by abnormal shifts in the thrombocyte intact/activated forms ratio.