Analysis of CT and MRI Manifestations of Joubert Syndrome.

Objective: To investigate the computed tomography and magnetic resonance imaging manifestations of Joubert syndrome (JS). Method: In this retrospective analysis, we investigated the clinical and imaging characteristics of JS in a cohort of twelve pediatric patients with confirmed diagnoses. Specifically, we analyzed both computed tomography (CT) and magnetic resonance imaging (MRI) manifestations in this population. CTs were performed on four patients and MRIs were performed on twelve, respectively. Results: JS is characterized by specific CT and MRI findings, including midline fissure, batwing, or triangular formations of the fourth ventricle between the bilateral cerebellar hemispheres, and molar sign at the midbrain level. All twelve cases in this cohort exhibited these traits, along with other cerebral abnormalities, such as dysplasia of the corpus callosum in two cases, gray matter heterotopia in one case, and occipital meningocele in one case. Conclusion: JS has distinctive CT and MRI characteristics that can be clinically identified.

Association of CT and MRI Manifestations with Pathology in Dysembryoplastic Neuroepithelial Tumors.

Objective: To investigate the CT, MRI and pathological features of dysembryoplastic neuroepithelial tumor (DNET). Methods: The CT and MRI features of six cases of pathologically confirmed DNET were retrospectively analyzed and compared with pathology. Results: All six cases of DNET were solitary, and lesion in one case was located in the right parietal lobe, one case in the right frontal lobe, one case in the cerebellar vermis, one case in the right temporo-parietal occipital lobe, one case in the left basal ganglia, and one case in the pineal gland. CT and MRI showed cystic solid tumor in all six cases, of which four showed calcification. In CT images, the cystic components appeared low-density, solid nodules, septa, and cyst walls were slightly high-density, and calcifications were high-density. In MRI images, the cystic components were hypointense on T1WI and hyperintense on T2WI, solid nodules, septa and cyst walls were iso-intense or slightly hyperintense on T1WI and T2WI sequences, and calcifications were all hypointense. On enhanced scan, the cystic components were not enhanced, and the solid nodules, septa, and cyst walls were inhomogeneously enhanced. Conclusion: The imaging manifestations of DNET are characteristic, and the combination of clinical and imaging features can greatly improve diagnostic accuracy.

Circulating TNFR1 exosome-like vesicles partition with the LDL fraction of human plasma.

Extracellular type I tumor necrosis factor receptors (TNFR1) are generated by two mechanisms, proteolytic cleavage of TNFR1 ectodomains and release of full-length TNFR1 in the membranes of exosome-like vesicles. Here, we assessed whether TNFR1 exosome-like vesicles circulate in human blood. Immunoelectron microscopy of human serum demonstrated TNFR1 exosome-like vesicles, with a diameter of 27-36nm, while Western blots of human plasma showed a 48-kDa TNFR1, consistent with a membrane-associated receptor. Gel filtration chromatography revealed that the 48-kDa TNFR1 in human plasma co-segregated with LDL particles by size, but segregated independently by density, demonstrating that they are distinct from LDL particles. Furthermore, the 48-kDa exosome-associated TNFR1 in human plasma contained a reduced content of N-linked carbohydrates as compared to the 55-kDa membrane-associated TNFR1 from human vascular endothelial cells. Thus, a distinct population of TNFR1 exosome-like vesicles circulate in human plasma and may modulate TNF-mediated inflammation.

Monoclonal antibodies reactive with the BAF155 (SMARCC1) and BAF170 (SMARCC2) components of human SWI/SNF-related complexes.

Mammalian SWI/SNF-related chromatin remodeling complexes are required for transcription controls that underlie differentiation, development, and tumor suppression. The complexes each consist of an ATPase of the SWI2/SNF2 family and approximately seven stably associated non-catalytic subunits. In spite of the importance of these complexes to biological processes, monoclonal antibodies to the various subunits have not been readily available. Mammalian complexes can vary in subunit composition, but the BAF155 (SMARCC1) subunit and a closely related protein, BAF170 (SMARCC2), appear to be ubiquitous components. Here we report the development of antibodies raised against a BAF155-derived peptide. The antibodies were raised against a single peptide of 18 amino acids. However, hybridomas expressing antibodies of two different specificities were isolated. One, designated DXD7, is specific for BAF155. The other, designated DXD12, is reactive with both BAF155 and BAF170. The antibodies are reactive against both native and denatured proteins, and are suitable for immunoprecipitation and Western blots. The DXD7 antibody is suitable additionally for immunofluorescence assays.

Proteasome inhibition induces TNFR1 shedding from human airway epithelial (NCI-H292) cells.

The type 1 55-kDa TNF receptor (TNFR1) is an important modulator of lung inflammation. Here, we hypothesized that the proteasome might regulate TNFR1 shedding from human airway epithelial cells. Treatment of NCI-H292 human airway epithelial cells for 2 h with the specific proteasome inhibitor clasto-lactacystin beta-lactone induced the shedding of proteolytically cleaved TNFR1 ectodomains. Clasto-lactacystin beta-lactone also induced soluble TNFR1 (sTNFR1) release from the A549 pulmonary epithelial cell line, as well as from primary cultures of human small airway epithelial cells and human umbilical vein endothelial cells. Furthermore, sTNFR1 release induced by clasto-lactacystin beta-lactone was not a consequence of apoptosis or the extracellular release of TNFR1 exosome-like vesicles. The clasto-lactacystin beta-lactone-induced increase in TNFR1 shedding was associated with reductions in cell surface receptors and intracytoplasmic TNFR1 stores that were primarily localized to vesicular structures. As expected, the broad-spectrum zinc metalloprotease inhibitor TNF-alpha protease inhibitor 2 (TAPI-2) attenuated clasto-lactacystin beta-lactone-mediated TNFR1 shedding, which is consistent with its ability to inhibit the zinc metalloprotease-catalyzed cleavage of TNFR1 ectodomains. TAPI-2 also reduced TNFR1 on the cell surface and attenuated the clasto-lactacystin beta-lactone-induced reduction of intracytoplasmic TNFR1 vesicles. This suggests that TNFR1 shedding induced by clasto-lactacystin beta-lactone involves the zinc metalloprotease-dependent trafficking of intracytoplasmic TNFR1 vesicles to the cell surface. Together, these data are consistent with the conclusion that proteasomal activity negatively regulates TNFR1 shedding from human airway epithelial cells, thus identifying previously unrecognized roles for the proteasome and zinc metalloproteases in modulating the generation of sTNFRs.