Efficient stem cell isolation from under vacuum preserved tissue samples.

Different approaches for the isolation of stem/progenitor cells have been reported, including stem cell selection in stringent culture conditions. We evaluated the possibility of isolating human progenitor cells from surgical specimens preserved by under vacuum sealing and cooling, a clinical practice approached by several hospitals as alternative to formalin. Renal tissue samples (n = 20) maintained under vacuum from 6 to 48 h at 4°C were used to isolate human renal CD133(+) progenitor cells.

Critical steps in tissue processing in histopathology.

Histopathological diagnosis using Formalin-Fixed Paraffin Embedded (FFPE) tissues is essential for the prognostic and therapeutic management of cancer patients. Pathologists are being confronted with increasing demands, from both clinicians and patients, to provide immunophenotypic and gene expression data from FFPE tissues to allow the planning of personalized therapeutic regimens. Recent improvements in the protocols for pre-analysis processing of pathological tissues aim to better preserve cellular details and to conserve antigens and nucleic acid sequences.

Hypoxia modulates the undifferentiated phenotype of human renal inner medullary CD133+ progenitors through Oct4/miR-145 balance.

Low-oxygen tension is an important component of the stem cell microenvironment. In rodents, renal resident stem cells have been described in the papilla, a relatively hypoxic region of the kidney. In the present study, we found that CD133(+) cells, previously described as renal progenitors in the human cortex, were enriched in the renal inner medulla and localized within the Henle's loop and thin limb segments.

Formalin fixation at low temperature better preserves nucleic acid integrity.

Fixation with formalin, a widely adopted procedure to preserve tissue samples, leads to extensive degradation of nucleic acids and thereby compromises procedures like microarray-based gene expression profiling. We hypothesized that RNA fragmentation is caused by activation of RNAses during the interval between formalin penetration and tissue fixation. To prevent RNAse activation, a series of tissue samples were kept under-vacuum at 4°C until fixation and then fixed at 4°C, for 24 hours, in formalin followed by 4 hours in ethanol 95%.

Added value of combined gene and protein expression of CK20 and CEA in non-macroscopically involved lymph nodes of colorectal cancer.

A methacarn fixation permits an approach that comprises multiple techniques. In this study the procedure is used to examine 100 mesenteric lymph nodes from patients with colon cancer by means of histology, immunohistochemistry (IHC), and reverse transcriptase polymerase chain reaction (RT-PCR). The evaluated nodes are found to be grossly free of metastases.

Technical limits of comparison of step-sectioning,immunohistochemistry and RT-PCR on breast cancer sentinel nodes: a study on methacarn-fixed tissue.

The optimal pathological assessment of sentinel nodes (SLNs) in breast cancer is a matter of debate. Currently, multilevel histological evaluation and immunohistochemistry (IHC) are recommended, but alternative RT-PCR procedures have been developed. To assess the reliability of these different procedures, we devised a step-sectioning protocol at 100 micron-intervals of 74 SLNs using methacarn fixation.