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.

[Sarcoidosis gastropathy: diagnosis and contribution of echo-endoscopy]. / Gastropathie sarcoïdosique: diagnostic et apport de l'écho-endoscopie.

We report a case of gastric sarcoidosis in a 36-year old woman. The clinical and endoscopic ultrasonography findings initially suggested linitis plastica. Subsequently the discovery of unexpected gastric and then, bronchial granulomas after bronchoscopy and bilateral ocular fixation on gallium scanning, led to the diagnosis of sarcoidosis. Endoscopic ultrasonography showed abnormal hypertrophy of the third hyperechoic layer. These findings usually suggest among the etiologies of giant gastric folds, malignant diseases and particularly linitis plastica.

[Hepatocellular carcinoma in cirrhosis: semeiology and performance of magnetic resonance imaging and lipiodol computed tomography]. / Carcinome hépatocellulaire sur cirrhose: sémiologie et performances de l'imagerie par résonance magnétique et de la tomodensitométrie après artériographie lipiodolée.

OBJECTIVES: a) Describe hepatocellular semiology in magnetic resonance imaging and lipiodol computerized tomography in patients with cirrhosis, who are candidates for surgery; b) Clarify the respective roles of magnetic resonance imaging and lipiodol computerized tomography in hepatocellular detection. METHODS: Twenty four patients with suspected hepatocellular carcinoma underwent successive magnetic resonance imaging and lipiodol computerized tomography. Thirty-four of the 67 lesions seen by lipiodol computerized tomography and 28 of 52 lesions seen by magnetic resonance imaging were confirmed histologically. RESULTS: In lipiodol computerized tomography, 44% of hepatocellular carcinomas had a dense and homogeneous pattern; 24% had a homogeneous but slightly dense pattern. Sixteen distinct deposits were described: 4 were confirmed as hepatocellular carcinoma and 12 were not controlled histologically. In magnetic resonance imaging 57% of hepatocellular carcinomas have a high intensity on T1 and T2 weighted spin echo images, 38% were hyperintense on T2 and hypo or isointense on T1 weighted images. Eighty-six percent of hyperintense T1 and T2 weighted images were hepatocellular carcinoma. When the gold standard was histology, lipiodol computerized tomography sensitivity (81%) was higher than magnetic resonance imaging (68%). When the gold standard was lipiodol computerized tomography, the sensitivity of magnetic resonance imaging was 47 +/- 12%. CONCLUSIONS: a) The sensitivity of lipiodol computerized tomography was better than resonance magnetic imaging; b) the homogeneous and slightly dense pattern corresponded to a hepatocellular carcinoma in 50% of cases; c) on magnetic resonance imaging any lesions with high intensity on T1 and T2 spin echo images strongly suggests hepatocellular carcinoma; d) if surgical resection after ultrasonography is being considered, the second step should be an magnetic resonance imaging.