Morphometric analysis of heparin coated versus standard intra-aortic balloons

The adverse effects of systemic heparin administration has led to the development of heparin coated devices. Intra-aortic balloons are frequently used in clinical settings in which complications of systemic heparin, especially bleeding, are feared. The current study evaluated the thromboresistance of heparin coated intra-aortic balloons. Six bovine calves were chosen for the experiment. In each animal, three intra-aortic balloons were inserted, and set to the automatic mode: two in the vena cava for 15 min and 45 min, respectively, and one in the aorta for 6 hr. There were nine standard and nine heparin coated intra-aortic balloons. At the end of the procedures, three samples of each intra-aortic balloon were analyzed with scanning electron microscopy for computed analysis of the balloon surface covered with fibrin and cells. The scanning electron microscopy analysis showed no deposit at any time interval on the heparin coated sample surfaces, whereas 3.6% +/- 9.2% (mean +/- SD) of the standard sample surfaces were covered with deposits at 15 min (p = 0.06), 14.8% +/- 24.3% at 45 min (p = 0.01), and 4.4% +/- 12.4% at 6 hr (p = 0.06). Strikingly, none of the 27 heparin coated samples showed any microscopic deposits, whereas 11 of the 27 standard samples did (p < 0.002). Heparin coated intra-aortic balloons appear to be a promising strategy, especially for patients with absolute or relative contraindications to systemic heparinization.     

Transchoroidal approach to the third ventricle: an anatomic study of the choroidal fissure and its clinical application

OBJECTIVE: We review the anatomic features of the lateral ventricle, the foramen of Monro, the third ventricle, and the choroidal fissure, and we describe the transchoroidal approach to the third ventricle. This approach consists of opening the taenia fornicis of the choroidal fissure in the body of the lateral ventricle and approaching the third ventricle between the two internal cerebral veins. This route allows further posterior enlargement of the foramen of Monro without sacrificing any neural structures. When necessary, the anterior septal vein can be sacrificed. METHODS: Twenty adult cadaveric brains and four adult cadaveric heads were studied, using a magnification ranging from 3 times to 40 times, after perfusion of the arteries and veins with colored latex. RESULTS: The choroidal fissure is a natural cleft between the thalamus and the fornix, and it is identified by following the choroid plexus in the lateral ventricle. The choroid plexus in the body of the lateral ventricle originates from the tela choroidea of the roof of the third ventricle and is apparently attached to the fornix by the taenia fornicis and to the thalamus by the taenia choroidea. The taenia is actually the ependyma that covers the internal wall of the ventricular cavity and the choroid plexus. CONCLUSION: An understanding of the choroidal fissure is fundamental for use of the transchoroidal approach. Unlike transforaminal, subchoroidal, subforniceal, and interforniceal approaches to the third ventricle, which sacrifice some neural or vascular structures, the transchoroidal approach follows a natural route, and certainly it is one of the options to be considered when entry into the third ventricle is required.     

The use of nonhomologous scatchard analysis in the evaluation of ligand-protein interactions

Scatchard plots are widely used for the graphical presentation of receptor-ligand binding data. When a combination of labelled and unlabelled ligand molecules is used in a binding assay, equations for Scatchard plots are readily available if the labelled and unlabelled ligands have similar binding affinities. In this article, Everardus van Zoelen, Roel Kramer, Herman van Moerkerk and Jacques Veerkamp present mathematical equations to obtain the binding characteristics of an unlabelled ligand in a Scatchard plot, which has a dissociation equilibrium constant different from that of the labelled ligand used.     

Managing the uncertainties of low-level radioactive waste disposal

A special program developed by the authors, called Pombe, identifies protein coding regions in the Schizosaccharomyces pombe genome. Linear discriminant analysis was applied to predict 5'-terminal, internal, 3'-terminal exons (coding-exon) and introns. The accuracy of the prediction was tested by cross verifications. The sensitivity, specificity and correlation coefficient for the internal exon prediction were 98.5%, 99.9% and 98.3% respectively at the nucleotide level. Open reading frames were studied and used to predict intron-less genes: 99.0% of such genes were identified with correct stopping sites. The gene structure was determined by dynamic programming and the prediction achieved 97.0% correlation coefficient at the nucleotide level. The program is available at http:(/)/clio.cshl.org/genefinder.