Biomedical subjects
Publications and source records attributed to F Imani.
Intradural hydatidosis is a very uncommon form of vertebrospinal hydatidosis. We report a intradural lumbar localization, presenting the magnetic resonance imaging findings. We emphasize MRI for diagnosis and follow-up in search for residual or recurrent lesions.
We report 4 cases of malignant thoraco-pulmonary small-cell tumors (Askin tumor). Only two cases were operated. We emphasize the difficult histological diagnosis and demonstrate the importance of complete removal for survival. Prognosis remains poor.
OBJECTIVES: To describe the renewed interest in Candida infections in general and urinary tract infections in particular, due to a recrudescence of immunodepressed patients and a better knowledge of their clinical and radiological manifestations. MATERIAL AND METHODS: The authors report 2 cases of Candida bezoars diagnosed by IVU, ultrasonography and CT scan in two insulin-dependent diabetics. RESULTS: The first case presented with right renal involvement, in the form of delayed renal secretion on IVU with the presence of a pelvic filling defect, dilatation of the upper tract cavities on ultrasonography with a dilated renal pelvis occupied by an echogenic formation with no posterior acoustic shadow. CT showed a slightly heterogeneous low-density lesion with no contrast enhancement. The second case presented with right pelvic and vesical involvement. The diagnosis of urinary candidiasis was confirmed, in the first case, by the presence of whitish lumps on catheterization, for which analysis and culture were in favour of candidiasis and, in the second case, by direct examination and urine culture. Treatment with amphotericin B led to improvement followed by disappearance of the signs in both cases. CONCLUSION: In addition to laboratory examinations, noninvasive imaging techniques, mainly ultrasonography and CT, but also percutaneous aspiration, constitute a decisive element in the diagnostic and therapeutic management of urinary candidiasis.
Hydatid thymic cyst is exceptional. The diagnosis is suspected by radiology and epidemiology. Serology tests provide variable results and surgery is the only treatment. We report a case of thymic hydatid cyst in a 20-year-old man who had no other localizations. Diagnosis was confirmed at surgery and by histology.
The protein tyrosine kinase Csk downregulates the activity of the Src family of kinases and has a negative effect on signal transduction through several Src kinase-associated receptors. Because the Src-family kinase Lyn plays a pivotal role in FcepsilonRI-mediated cellular activation, we examined whether Csk is involved in FcepsilonRI signaling events. Using anti-Csk antibodies and recombinant fusion proteins we detected a single tyrosine-phosphorylated protein of 60 kD (herein referred to as 'p60') that associates with the SH2 domain of Csk after stimulation of the FcepsilonRI. p60 phosphorylation reached a maximum within one minute and remained constant while the receptors were aggregated; disaggregation of the receptors resulted in rapid dephosphorylation of p60. The phosphorylation of p60 was only detected after activation by IgE and antigen and not by stimulation with PMA and/or ionomycin. Phosphorylated p60 was associated entirely with the membrane fraction of the cells. A considerable fraction of Csk was associated with the membrane in both unstimulated and stimulated cells, this fraction did not change upon activation. p60 coprecipitated with Csk from both unstimulated and FcepsilonRI stimulated cells and was phosphorylated by the immunocomplex. Total kinase activity of Csk immunoprecipitates increased upon FcepsilonRI stimulation. p60 did not react with antibodies to a number of known signaling molecules, including the recently cloned, GAP-associated protein, p62dok. Our data demonstrate that Csk associates with a membrane-anchored protein complex that is directly involved in FcepsilonRI signal transduction.
An epidemiologic association between viral infections and the onset of asthma and allergy has been documented. Also, evidence from animal and human studies has suggested an increase in antigen-specific immunoglobulin E (IgE) production during viral infections, and elevated levels of IgE are characteristic of human asthma and allergy. Here, we provide molecular evidence for the roles of viral infection and of activation of the antiviral protein kinase (PKR) (double-stranded-RNA [dsRNA]-activated protein kinase) in the induction of IgE class switching. The presence of dsRNA, a known component of viral infection and an activator of PKR, induced IgE class switching as detected by the expression of germ line epsilon in the human Ramos B-cell line. Furthermore, dsRNA treatment of Ramos cells resulted in the activation of PKR and in vivo activation of the NF-kappaB complex. Interestingly, infection of Ramos cells with rhinovirus (common cold virus) serotypes 14 and 16 resulted in the induction of germ line epsilon expression. To further evaluate the role of PKR in the viral induction of IgE class switching, we infected Ramos cells with two different vaccinia virus (cowpox virus) strains. Infection with wild-type vaccinia virus failed to induce germ line epsilon expression; however, a deletion mutant of vaccinia virus (VP1080) lacking the PKR-inhibitory polypeptide E3L induced the expression of germ line epsilon. Collectively, the results of our study define a common molecular mechanism underlying the role of viral infections in IgE class switching and subsequent induction of IgE-mediated disorders such as allergy and asthma.
The authors report the case of a 28-year-old man in whom the diagnosis of hydatic cyst of the heart was strongly suspected on echocardiography and CT-scan and confirmed by surgery. The interest of this case is based the total clinical latency of this hydatic cyst discovered by echocardiography during a systematic checkup for cerebrovascular disorders. Echocardiography and spiral scanography with bidimensionnal reconstruction in coronal and sagittal planes allowed a rapid anatomic and topographic diagnosis. CT-scan also identified spread of echinococcosis and discovered a calcifield hydatid cyst of the liver and a multivesicular hydatid cyst of the left kidney.
Among epithelial tumors, squamous cell carcinomas represent only 3 to 7% of the cases in the temperate countries, but constitute the most frequent histologic kind in bilharzien endemic zones and 17% of intradiverticulars tumors. The adenocarcinoma is found most often in the bladder dome, representing only 0.3 to 3% of all bladder tumors. Invasive cancer in a neighboring organ (digestive tract, genital organs) must be eliminated. In most cases, combining ultrasonography and intravenous urography can be helpful for diagnosis of intradiverticular carcinoma or bladder dome tumor. Computed tomography and magnetic resonance images are the best methods for positive diagnosis and extension exploration for tumors of the dome and base of the bladder. In this work, we report a series of five cases of uncommon bladder carcinoma. Three of the cases were intradiverticular squamous cell tumors and two were adenocarcinoma of the bladder dome.
Unlike epithelial tumors, connective tissue tumors are uncommon, representing only 3% of all bladder tumors. Leiomyoma of the bladder is the most frequent non-epithelial benign tumor of the bladder. Magnetic resonance imaging (MRI) is highly useful for diagnostic purposes and to determine the degree of extension. Only few reports of sonographic findings have been reported for leiomyoma of the bladder. The tumor usually develops within the bladder. Extravesicular formations have also been reported as well as a few intramural localizations. The characteristic feature is the absence of mucosal involvement. We analyzed the MRI findings in a case of leiomyoma of the bladder with intra and extravesicular development, inflammatory reaction of the bladder wall and uterine adherences in a woman with a past history of chronic cystitis. The role of diagnostic MRI is discussed.
Dilatation of the common bile duct is rarely caused by cystic formations. Though the pathogenesis is uncertain, congenital disorders have been suggested. Most cases are observed in small children (80% female predominance) with only 20% of the cases reported in adults. Clinical signs vary. Recurrent acute pancreatitis has been reported but is rare. New imaging techniques using CT-scan cholangiography and sometimes MR cholangiography have greatly improved the diagnostic approach. MR of the bile ducts is a recent noninvasive technique enabling an analysis of the biliopancreatic ducts without contrast injection into the bile. To our knowledge, cystic dilatation of the common bile duct has not been previously reported in the literature. We report an interesting case in a 25-year-old woman who developed an episode of acute pancreatitis during the post partum period. We describe the clinical aspects and the different imaging findings, including magnetic resonance cholangiography results.
Interleukin 4 (IL-4) is a potent cytokine produced by T cells and to a lesser extent by tumor-associated natural killer cells, basophils, and mast cells. IL-4 treatment of T cells and macrophages leads to augmentation of their cytotoxic activity. In human B cells, IL-4 is a potent stimulator of Ig class switching from IgM to IgE. The diverse biological responses induced by IL-4 are mediated through a high affinity receptor complex (IL-4R). Although a wealth of information has accumulated regarding IL-4R, the exact mechanisms of IL-4R-mediated signaling pathways in human B cells are not well defined. In an attempt to characterize the IL-4-induced signals in human B cells, we have found that IL-4 treatment induced rapid dephosphorylation of the 85-kDa regulatory subunit of phosphatidylinositol 3-kinase. To identify the protein-tyrosine phosphatase involved in the IL-4-mediated dephosphorylation, we performed Western blot analysis using monoclonal antibodies specific to protein-tyrosine phosphatases. Upon IL-4 treatment, SHP-1 was specifically translocated to the cellular membrane fraction. Furthermore, immunoprecipitation studies revealed that SHP-1 could be specifically coimmunoprecipitated with the IL-4R as well as with phosphatidylinositol 3-kinase (p85). Collectively, our observations suggest that in addition to protein phosphorylation, protein tyrosine dephosphorylation may play a role in the IL-4-induced signaling pathways.
Venous leiomyosarcomas are rare and predominantly arise in the inferior vena cava (IVC). The clinical findings, often not very suggestive and nonspecific, sometimes precede the diagnosis by several years. According to the literature, leiomyosarcoma of the IVC generally occurs in middle-aged women. Modern imaging techniques, especially magnetic resonance imaging (MRI) can now establish the diagnosis of leiomyosarcoma of the IVC with a high probability and allow assessment of operability. The authors report a case of leiomyosarcoma of the IVC in a 24-year-old male patient, confirmed by intravenous biopsy. They present the MR features of this malignant tumour, rarely reported in the literature, and emphasize the value of this examination in the operability staging. The 3D imaging provided by MRI allows intra and extraluminal staging and involvement of adjacent organs. It also allows optimal evaluation of the effects on flow, circulatory slowing or thrombosis and, due to its high contrast resolution, it is more sensitive to distinguish clot from tumour nodule.
The rupture of hydatid cysts into the abdominal aorta is an exceptional and serious complication of the hydatid disease. We report a case of hydatid false-aneurysm of the abdominal aorta, explored by US Doppler, C.T. and arteriography.
BACKGROUND: Advanced glycation end products (AGE), the reactive derivatives of nonenzymatic glucose-protein condensation reactions, are implicated in the multiorgan complications of diabetes and aging. An AGE-specific cellular receptor complex (AGE-R) mediating AGE removal as well as multiple biological responses has been identified. By screening an expression library using antibody against a previously identified component of the AGE-R complex p90, a known partial cDNA clone was isolated with homology to galectin-3, a protein of diverse identity, and member of the galectin family. MATERIALS AND METHODS: To explore this unexpected finding, the nature of the interactions between galectin-3 and AGE was studied using intact macrophage-like RAW 264.7 cells, membrane-associated and recombinant galectin-1 through -4, and model AGE-ligands (AGE-BSA, FFI-BSA). RESULTS: Among the members of this family (galectin-1 through 4), recombinant rat galectin-3 was found to exhibit high-affinity 125I-AGE-BSA binding with saturable kinetics (kD 3.5 x 10(7) M-1) that was fully blocked by excess unlabeled naturally formed AGE-BSA or synthetic FFI-BSA, but only weakly inhibited by several known galectin-3 ligands, such as lactose. In addition to the p90, immunoprecipitation with anti-galectin-3, followed by 125I-AGE-BSA ligand blot analysis of RAW 264.7 cell extracts, revealed galectin-3 (28 and 32 kD), as well as galectin-3-associated proteins (40 and 50 kD) with AGE-binding activity. Interaction of galectin-3 with AGE-BSA or FFI-BSA resulted in formation of SDS-, and beta-mercaptoethanol-insoluble, but hydroxylamine-sensitive high-molecular weight complexes between AGE-ligand, galectin-3, and other membrane components. CONCLUSIONS: The findings point toward a mechanism by which galectin-3 may serve in the assembly of AGE-R components and in the efficient cell surface attachment and endocytosis by macrophages of a heterogenous pool of AGE moieties with diverse affinities, thus contributing to the elimination of these pathogenic substances.
During normal aging and in chronic diabetes the excessive accumulation of reactive glucose-protein or glucose-lipid adducts known as advanced glycosylation endproducts (AGEs) has been shown to induce tissue dysfunction, in part through interaction with AGE-specific receptors on monocyte/macrophages and other cells. Recognizing that circulating lymphocytes trafficking through tissues interact with tissue AGEs, we searched for the expression of AGE-binding sites on peripheral blood T lymphocytes. Resting rat and human T cells bound 125I-AGE-albumin with an affinity of 7.8 x 10(7) M-1, whereas, after stimulation with phytohemagglutinin (PHA) for 48 h, binding affinity increased to 5.8 x 10(8) M-1. Flow cytometric analysis of resting rat T cells using polyclonal antibodies raised against rat liver AGE-binding proteins (p60 and p90) revealed the constitutive expression of both immunoreactivities. The number of resting CD4+ and CD8+ T cells positive for anti-p60 antibody binding (34.2 and 58.5%, respectively) increased to 92 and 90% of cells after 48-h stimulation with PHA. Exposure of PHA-activated T lymphocytes to AGE-albumin enhanced expression of interferon gamma (IFN-gamma) mRNA 10-fold and induced greater elaboration of the mature protein than did exposure to unmodified protein or PHA treatment alone. These data indicate that T cells contain an inducible system of surface receptors for AGE-modified proteins, and that receptor occupancy is linked to lymphokine production. This T cell AGE-receptor system might serve to target lymphocytes to AGE-rich tissues and involve them in the regulation of tissue homeostasis either by assisting in macrophage-dependent clearance of AGE-proteins, or by exerting direct antiproliferative action on mesenchymal cells. Under conditions of excessive AGE-protein and AGE lipid accumulation (e.g., aging and diabetes), enhanced production of AGE-induced IFN-gamma may accelerate immune responses that contribute to tissue injury.
The authors report about 40 cases of Behçet's disease with vascular involvement, i.e. 32% of a 125 case series. The results were marked by the high frequency of venous involvement (36 cases, including 28 thrombophlebitis of the deep trunks of the lower limbs) and the rarity of arterial involvement (6 cases). Arterial and venous involvements were associated in only 2 cases. Inferior vena caval thrombosis was recognized in 4 cases, including 3 with associated lower limb thrombosis. Superior vena caval thrombosis is found in 6 cases. Superior cavography has allowed demonstrating thrombosis and assessing its extent, to the innominate veins in all cases, to the subclavian veins in 3 cases, and to the axillary veins in 1 case. Cases of arterial involvement include 5 cases of pulmonary arterial aneurysm and 1 of upper limb arteritis affecting the humeral and cubital arteries. It has been revealed by hemoptysis in all cases. Angiography has allowed establishing the diagnosis of aneurysm in 4 cases (3 with partial thrombosis and 1 without thrombosis). CT revealed the diagnosis of completely thrombosed aneurysms not opacified by angiography in another case.
The authors report about a series of 38 patients with hepatic cysts (HHC) that had a pseudotumoral form on sonography (type IV in Gharbi's classification), that were explored both with sonography and with CT. While sonography had made the diagnosis of HHC possible in 4 cases out of 38 only, CT easily established this diagnosis in all cases. In addition, the latter technique has demonstrated the various tissue components accounting for the pseudotumoral sonographic image (hydatid sand, parietal calcifications, daughter cysts, intracystic air). It also allows assessing the number of sites and, better than with sonography, the signs of rupture of a hydatid cysts.
Persistent sciatic is a vascular malformation resulting in the embryo from the preferential growth of the ischiatic posterior axis remaining atrophic. We report here two cases of unilateral, complete and incompleted, persistent sciatic arteries, complicated by buttock aneurysm.