Magnetically guided recellularization of decellularized stented porcine pericardium-derived aortic valve for TAVI.

Application of somatic stem cells for growth, proliferation, and differentiation in a three-dimensional pattern is an important aspect in tissue engineering. Here, we report on our bioreactor, which we applied for magnetically guided recellularization of nitinol-stented valve. Human-derived unrestricted somatic stem cells were cultured in medium in our pulsatile dynamic bioreactor for 4-6 days. Stented valves were prepared by decellularization of porcine pericardium and construction of stented tissue-engineered valves (n = 8). A magnetic field was created around the bioreactor to prevent the loss of cells. In the control group, no magnetic device was used (n = 4). Morphological characterization was assessed by immunohistochemical staining of paraffin sections and electron microscopy. The bioreactor enabled the preservation of physiologic culture conditions with aerobic cell metabolism and physiological pH values. Histological analysis showed homogeneous seeding of the pericardium with progenitor cells in the recellularized samples, whereas no cell seeding could be observed in the nonmagnetic group. Our magnetically guided multifunctional bioreactor allows for an efficient three-dimensional culturing of somatic stem cells on decellularized organ-specific matrix.

Portal application of human unrestricted somatic stem cells to support hepatic regeneration after portal embolization and tumor surgery.

Insufficient liver remnant volume still precludes patients with potentially resectable tumors from curative surgery. Clinically, it has been demonstrated that transplanted adult stem cells promote liver regeneration. However, the mechanisms of the observed functional improvements are unknown. The aim of our study was to evaluate the impact of transplanted human multipotent cord blood-derived unrestricted somatic stem cells (USSC) on liver regeneration and identify the underlying mechanisms in an ovine model. We performed partial embolization of the right liver lobe and grafted USSC in the portal venous system of the left liver lobe. After 4 weeks, livers were explanted and analyzed for differentiation of USSC into hepatocytes by histopathologic examination and for fusion of USSC with recipient hepatocytes by single-cell polymerase chain reaction. The studies revealed that transplanted USSC differentiate into hepatocytes and produce human albumin. No ovine DNA was found in the hepatocytes with a human phenotype. Transplantation of USSC enhances the number of viable hepatocytes in liver disease by differentiation and opens new therapeutic perspectives.

Virtual-karyotyping with SNP microarrays in morphologically challenging renal cell neoplasms: a practical and useful diagnostic modality.

Approximately 7 % of renal cell tumors are reported to be "unclassified" renal cell carcinoma (RCC) under the current (morphology-based) classification. Genetic lesions characteristic for RCC subtypes can be identified by virtual karyotyping with single nucleotide polymorphisms (SNP) microarrays. In this study, we examined whether virtual karyotypes could be used to better classify a cohort of morphologically challenging/unclassified RCC. Tumor resection specimens from 21 patients were profiled by virtual karyotyping with Affymetrix 10K 2.0 or 250K Nsp SNP mapping arrays and were also evaluated independently by a panel of 7 genito-urinary pathologists. Tumors were classified by the established pattern of genomic imbalances based on a reference cohort of 98 cases with classic morphology and compared with the morphologic diagnosis of the pathologist panel. Virtual karyotyping analysis identified recognized patterns of chromosomal imbalances in all but 1 (16/17 or 94%) cases with successful analysis. Four cases failed owing to low DNA quality. All cases with a panel diagnosis of unclassified RCC and cases in which a majority diagnosis was not reached were classified by their virtual karyotypes. In 1 case, the molecular-based diagnosis was in disagreement with the majority diagnosis. One case with a majority diagnosis of oncocytoma showed a novel genomic pattern not previously identified in the classic morphology cohort. We conclude that virtual karyotypes generated by SNP arrays are a valuable tool for increasing diagnostic accuracy in morphologically challenging or unclassified renal neoplasms. We consider that this technique is a feasible and practical approach for resolving difficult-to-diagnose renal tumors in clinical practice.

Spontaneous bacterial pericarditis with tamponade due to Ureaplasma spp.

Infectious pericardial effusion with tamponade is an uncommon but life-threatening disease. We report an unusual case of spontaneous Ureaplasma pericardial effusion with tamponade associated with pneumonia, pleural effusion, and urinary tract infection. All published cases of clinically invasive Ureaplasma infections in the adult population are also reviewed.

Virtual karyotyping with SNP microarrays reduces uncertainty in the diagnosis of renal epithelial tumors.

BACKGROUND: Renal epithelial tumors are morphologically, biologically, and clinically heterogeneous. Different morphologic subtypes require specific management due to markedly different prognosis and response to therapy. Each common subtype has characteristic chromosomal gains and losses, including some with prognostic value. However, copy number information has not been readily accessible for clinical purposes and thus has not been routinely used in the diagnostic evaluation of these tumors. This information can be useful for classification of tumors with complex or challenging morphology. 'Virtual karyotypes' generated using SNP arrays can readily detect characteristic chromosomal lesions in paraffin embedded renal tumors and can be used to correctly categorize the common subtypes with performance characteristics that are amenable for routine clinical use. METHODS: To investigate the use of virtual karyotypes for diagnostically challenging renal epithelial tumors, we evaluated 25 archived renal neoplasms where sub-classification could not be definitively rendered based on morphology and other ancillary studies. We generated virtual karyotypes with the Affymetrix 10 K 2.0 mapping array platform and identified the presence of genomic lesions across all 22 autosomes. RESULTS: In 91% of challenging cases the virtual karyotype unambiguously detected the presence or absence of chromosomal aberrations characteristic of one of the common subtypes of renal epithelial tumors, while immunohistochemistry and fluorescent in situ hybridization had no or limited utility in the diagnosis of these tumors. CONCLUSION: These results show that virtual karyotypes generated by SNP arrays can be used as a practical ancillary study for the classification of renal epithelial tumors with complex or ambiguous morphology.