Left atrial myxoma: diagnosis by digital subtraction intravenous angiography

Digital subtraction intravenous angiography (DSIVA) represents an important technical advance in angiographic diagnosis. Herein we present three patients with left atrial myxoma assessed by DSIVA. We review the role of DSIVA in evaluation of patients with suspected cardiac tumors and the importance of careful atrial-phase scrutiny in examinations obtained for other purposes (ie, pulmonary angiography and assessment of ventricular function).     

Expression and functional activity of CXCR-4 and CCR-5 chemokine receptors in human thymocytes

In this paper we addressed the expression of the HIV co-receptors CXCR-4 and CCR-5 in human thymocytes by phenotypic, molecular and functional approaches. Cytofluorimetric analysis disclosed that CXCR-4 was constitutively expressed by freshly isolated thymocytes (~10 000 molecules/cell in about 30% of thymocytes); the receptor was endowed with functional activity, as it mediated polarization, migration and intracellular Ca2+ increase in response to its ligand, SDF-1. On the contrary, CCR-5 expression in freshly isolated thymocytes was significantly lower (<4000 molecules/cell in less than 5% of the cells), and no functional response to CCR-5 agonists could be documented. Northern blot analysis of freshly isolated thymocytes showed high CXCR-4 mRNA levels, whereas the message for CCR-5 was barely detectable. On the other hand, a modest increase in the expression of CCR-5 was associated with in vitro thymocyte stimulation, and CCR-5 density at the cell surface attained CXCR-4 figures in most cases. None the less, no functional response to CCR-5 agonists could be documented in in vitro stimulated thymocytes. In vitro infection of thymocytes by CAT-expressing recombinant HIV bearing the envelope glycoproteins from different isolates showed that T-tropic strains, which use CXCR-4 as a co-receptor, were more efficient in infecting thymocytes than M-tropic strains, which preferentially use CCR-5. Altogether, these data indicate that expression of the major co-receptors involved in infection by M-tropic HIV strains is very poor in human thymocytes, and would suggest that thymocyte infection by M-tropic HIV strains may be a rare event in vivo.     

Loci on murine chromosomes 7 and 13 that modify the phenotype of the NOA mouse, an animal model of atopic dermatitis

The NOA (Naruto Research Institute Otsuka Atrichia) mouse is an animal model of allergic or atopic dermatitis, a condition characterized by ulcerative skin lesions with accumulation of mast cells and increased serum IgE. We reported earlier that a major gene responsible for dermatitis in the NOA mouse lay in the middle of chromosome 14, and that the incidence of disease clearly differed according to parental strain; the mode of inheritance was autosomal recessive with incomplete penetrance. In the study reported here, we searched for genes that might modify the NOA phenotype, and we identified two candidate loci that appeared to contain genes capable of modifying atopic or allergic dermatitis, one in the middle of chromosome 7 (χ² = 14.66; P = 0.00013 for D7Mit62) and the other in the telomeric region of chromosome 13 (χ² = 15.352; P = 0.000089 for D13Mit147). These loci correspond to regions of synteny in human chromosomes where linkages to asthma, atopy, or related phenotypes, such as serum IgE levels, have been documented. Received: December 18, 2000 / Accepted: January 19, 2001     

Using an Ultrasound Elasticity Microscope to Map Three-Dimensional Strain in a Porcine Cornea

An ultrasound elasticity microscope was used to map 3-D strain volume in an ex vivo porcine cornea to illustrate its ability to measure the mechanical properties of this tissue. Mechanical properties of the cornea play an important role in its function and, therefore, also in ophthalmic diseases such as kerataconus and corneal ectasia. The ultrasound elasticity microscope combines a tightly focused high-frequency transducer with confocal scanning to produce high-quality speckle over the entire volume of tissue. This system and the analysis were able to generate volume maps of compressional strain in all three directions for porcine corneal tissue, more information than any previous study has reported. Strain volume maps indicated features of the cornea and mechanical behavior as expected. These results constitute a step toward better understanding of corneal mechanics and better treatment of corneal diseases.