Hepatic venous pressure gradients measured by duplex ultrasound.

AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r=0.83, P<0.0001) and with the Child-Pugh score (r=0.63, P<0.0001). An acceleration index cut-off value of 1m.s(-2) provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient>12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r=0.45,P=0.01) and portal vein velocity (r=0.40,P=0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension.

Inhibition of IgE-mediated mast cell activation by the paired Ig-like receptor PIR-B.

The potential of the paired Ig-like receptors of activating (PIR-A) and inhibitory (PIR-B) types for modifying an IgE antibody-mediated allergic response was evaluated in mouse bone marrow-derived mast cells. Although mast cells produced both PIR-A and PIR-B, PIR-B was found to be preferentially expressed on the cell surface, where it was constitutively tyrosine phosphorylated and associated with intracellular SHP-1 protein tyrosine phosphatase. PIR-B coligation with the IgE receptor (FcepsilonRI) inhibited IgE-mediated mast cell activation and release of serotonin. Surprisingly, the inhibitory activity of PIR-B was unimpaired in SHP-1-deficient mast cells. A third functional tyrosine-based inhibitory motif, one that fails to bind the SHP-1, SHP-2, and SHIP phosphatases, was identified in parallel studies of FcepsilonRI-bearing rat basophilic leukemia (RBL) cells transfected with constructs having mutations in the PIR-B cytoplasmic region. These results define the preferential expression of the PIR-B molecules on mast cells and an inhibitory potential that can be mediated via a SHP-1-independent pathway.

[Evaluation of plain abdominal radiography prescriptions in a university hospital center]. / Evaluation de la prescription des radiographies de l'abdomen sans préparation dans un centre hospitalier.

OBJECTIVES: The aim of this study was to evaluate the prescription, impact and diagnostic utility of plain abdominal radiography in a University Hospital. METHODS: Plain abdominal radiography series performed over 15 consecutive days were evaluated for quality and agreement with the patient's clinical status. Agreement between the final diagnosis and the radiographic findings were also compared. Contribution of plain abdominal radiography to final diagnosis was assessed on the basis of the conclusions on the hospital discharge report or from those drawn from a telephone survey. The same relationship was also assessed in terms of clinician status (medical student, resident physician, senior physician). RESULTS: The series included 175 radiography series (11.6 per day). In 86% of the cases, the choice of views was adapted to the clinical context. In 14% it was not. The quality of the x-rays was found to be unsatisfactory in 17%, good in 63% and excellent in 20%. The radiography was considered to be contributive to the final diagnosis in 13% of the cases and non-contributive in 87%. Clinician status was not correlated with the degree of usefulness for final diagnosis. Finally, the prescription was in agreement with standard guidelines in 28% of the cases and not in agreement in 72%. CONCLUSION: Plain abdominal radiographs are neither sensitive nor specific, frequently misleading, and costly per specific and correct diagnosis. Better physician awareness is required to limit the number of unnecessary examinations.

MR evaluation of factors predicting the development of rotator cuff tears.

PURPOSE: The purpose of this work was to assess the incidence of various factors predicting impingement in the shoulder. METHOD: MR examination was used to assess various anatomic parameters in 46 patients with clinical abnormalities of the shoulder and 40 asymptomatic volunteers. All patients had undergone surgery, showing no rotator cuff tear. RESULTS: A few of the parameters evaluated were significantly different in the two groups: The acromion was more frequently curved or hook-shaped in patients than in volunteers. The acromiohumeral distances differed (4.87 mm in patients and 6.05 mm in volunteers); so did the coracohumeral distances (7.9 mm in patients and 8.9 mm in volunteers). The shape of the acromioclavicular joint and the anterior covering of the humerus, defined on the coronal view, also differed (1.07 mm in patients and 1.49 mm in volunteers). Only the shapes of the acromioclavicular joint and of the acromion were linked with age. CONCLUSION: All these factors reflected a decrease in the acromiohumeral space, except for the anterior covering of the acromial arch, which could be due to anterior instability.

[Imaging of acute urinary infections in adults. Radiologic findings and strategy for imaging procedures]. / Infection urinaire aiguë non tuberculeuse de l'adulte. Aspects radiologiques et stratégie d'exploration.

Urinary infection is very common in women. Generally no imaging is needed. The role of imaging is mandatory in the following cases: renal infection, urinary obstructive syndrome, immuno-compromised patients. The results of imaging in pathology are described: pyelonephritis, renal and perinephric abscesses with or without phlegmon, perinephritis and emphysematous perinephritis. A strategy for imaging procedures is proposed.

Primary malignant lymphoma of the urinary bladder: report of three cases and review of the literature.

We report three cases of a primary malignant lymphoma of the urinary bladder. The radiological features revealed a sessile mass of the lateral wall for one case, a circumferential thickening in the second, and two separated masses of the bladder wall in the last case. Primary malignant lymphoma of the urinary bladder is extremely rare. From a review of the literature, the clinical and radiological findings are discussed. In this paper we report the first case of urinary bladder lymphoma presented on CTas multiple masses.

[Evaluation of radiological medical practice at a hospital during night duty]. / Evaluation de l'activité radiologique de garde dans un centre hospitalier.

PURPOSE: To evaluate the radiological activity during night duty, in a University Hospital. Materials and methods. During 100 days, the radiological activity has been evaluated from examinations requiring radiologist (including US and CT, special X-ray examinations). The urgent nature and the agreement between the suspected disease and the final diagnose have been compared with the level of the clinician (medical student, resident, senior). RESULTS: 981 radiological examinations were performed on an emergency basis. In 39%, the examination was urgent or very urgent and for 61%, little urgent or non-urgent. The level of the clinician was correlated with the degree of emergency evaluated by the radiologist and with the agreement between suspected disease and the final diagnose (p<0. 0001). CONCLUSION: During night duty, the medical activity in radiology is not justified only by emergency, but also by the continuous hospital activities. Better formation of the physician is required to limit the number of examinations.

Signaling pathways engaged by NK cell receptors: double concerto for activating receptors, inhibitory receptors and NK cells.

Despite the absence of antigen-specific receptors at their surface, NK cells can selectively eliminate virus-infected cells, tumor cells and allogenic cells. A dynamic and precisely coordinated balance between activating and inhibitory receptors governs NK cell activation programs. Multiple activating and inhibitory NK cell surface molecules have been described, a group of them acting as receptors for MHC class I molecules. In spite of their heterogeneity, activating NK cell receptors present remarkable structural and functional homologies with T cell- and B cell-antigen receptors. Inhibitory NK cell receptors operate at early stages of activating cascades by recruiting protein tyrosine phosphatases via intra- cytoplasmic motifs (ITIM), a strategy which is widely conserved in hematopoietic and non-hematopoietic cells.

Early signaling via inhibitory and activating NK receptors.

This review focuses on recent findings on the structural features of inhibitory NK cell receptors containing immunoreceptor tyrosine-based inhibition motif (ITIM) and of NK cell activating receptors, both in human and mouse. First, the study of the inhibitory killer cell immunoglobulin-like receptors (KIR) unveiled the presence of intracytoplasmic ITIM and their capacity to recruit protein tyrosine phosphatases such as SHP-1 in vivo. A brief summary of the known SHP-1 targets may help us to understand the inhibition mediated by the KIR. The characterization of ITIM thus allowed the definition of a large group of inhibitory cell surface receptors. The second part of the review describes the known NK cell activating receptors. Most of them require association with ITAM-containing polypeptides in order to mediate cell activation.

Intraluminal duodenal diverticulum: radiological and endoscopic ultrasonography findings of an unusual cause of acute pancreatitis.

Intraluminal duodenal diverticulum is a rare congenital web of membrane which may be symptomatic when it becomes distended. This report describes a case revealed by presenting as an acute pancreatitis. The radiological findings are reported. The findings at CT, upper gastro-intestinal series, endoscopic ultrasound and endoscopic retrograde cholangiopancreatography are described and differential diagnostic features from choledochocele and duodenal duplication are discussed. By endoscopic ultrasonography, observation of a thin wall, without different layers such as choledochocele or duodenal duplication, may be useful for diagnosis.

How to extinguish lymphocyte activation, immunotyrosine-based inhibition motif (ITIM)-bearing molecules a solution?

ITIM-bearing molecules represent a novel family of inhibitory receptors expressed widely through the hematopoietic compartment. These molecules share certain features such as the presence in their intracytoplasmic domain of the so-called motif ITIM (ImmunoTyrosine-based Inhibition Motif). These molecules are able to recruit phosphatases on their phosphorylated ITIM and thus mediate a localized inhibition of the transduction pathways. The molecular basis of this inhibitory pathway is discussed below.

[Emphysematous pyelonephritis: apropos of 4 cases]. / Pyélonéphrite emphysémateuse: à propos de quatre observations.

PURPOSE: The propose of this study was to describe the imaging findings in four patients with emphysematous pyelonephritis and to perform a review of the literature. MATERIAL AND METHODS: Four cases of emphysematous pyelonephritis are presented. US and CT examinations were available for all patients. RESULTS: Gas within the kidney may be diagnosed by plain film or rarely by ultrasound, but its location and its extent are best evaluated by CT. A review of the literature shows that emphysematous pyelonephritis is a rare and life-threatening infection typically occurring in diabetic patients. CONCLUSION: CT is useful for diagnosing emphysematous pyelonephritis, especially when symptoms fail to resolve promptly with medical therapy.

Gene structure, expression pattern, and biological activity of mouse killer cell activating receptor-associated protein (KARAP)/DAP-12.

Natural killer cell and T cell subsets express at their cell surface a repertoire of receptors for MHC class I molecules, the natural killer cell receptors (NKRs). NKRs are characterized by the existence of inhibitory and activating isoforms, which are encoded by highly homologous but separate genes present in the same locus. Inhibitory isoforms express an intracytoplasmic immunoreceptor tyrosine-based inhibition motif, whereas activating isoforms lack any immunoreceptor tyrosine-based inhibition motif but harbor a charged amino acid residue in their transmembrane domain. We previously characterized KARAP (killer cell activating receptor-associated protein), a novel disulfide-linked tyrosine-phosphorylated dimer that selectively associates with the activating NKR isoforms. We report here the identification of the mouse KARAP gene, its localization on chromosome 7 and its genomic organization in five exons. Point mutation and transfection studies revealed that KARAP is a novel signaling transmembrane subunit whose transduction function depends on the integrity of an intracytoplasmic immunoreceptor tyrosine-based activation motif. In contrast to previous members of the immunoreceptor tyrosine-based activation motif polypeptide family, KARAP is ubiquitously expressed on hematopoietic and nonhematopoietic cells, suggesting its association with a broad range of activating receptors in a variety of tissues.

The paired Ig-like receptor PIR-B is an inhibitory receptor that recruits the protein-tyrosine phosphatase SHP-1.

An emerging family of cell surface inhibitory receptors is characterized by the presence of intracytoplasmic immunoreceptor tyrosine-based inhibition motifs (ITIM). These ITIM-bearing inhibitory receptors, which are typically paired with activating isoforms, associate with Src homology domain 2-containing phosphatases following ITIM tyrosine phosphorylation. Two categories of phosphatases are recruited by the ITIM-bearing receptors: the protein-tyrosine phosphatases, SHP-1 and SHP-2, and the polyphosphate inositol 5-phosphatase, SHIP. The dynamic equilibrium of B cell activation is partially controlled by two well known ITIM-bearing receptors, CD22 and FcgammaRIIB, a low affinity receptor for IgG. We describe here that a murine ITIM-bearing molecule, PIR-B, can also negatively regulate B cell activation. Tyrosine-phosphorylated ITIMs allow PIR-B to associate with SHP-1 but not with SHIP. Engagement of PIR-B thereby initiates a SHP-1-dependent inhibitory pathway that may play an important role in regulating B lymphocyte activation.

[Imaging of prostatic leiomyosarcoma and contribution of MRI]. / Imagerie d'un léiomyosarcome prostatique et apport de l'IRM.

A case of leiomyosarcoma of the prostate is presented. Adult prostatic leiomyosarcoma is a rare tumor with a poor prognosis. US-CT and MRI findings are described.