Phase-changing sacrificial layer fabrication of multilayer polymer microfluidic devices. (57/216)

We present a new approach for fabricating multilayer microfluidic devices in poly(methyl methacrylate). Paraffin wax was used as a phase-changing sacrificial layer to protect microstructures during solvent bonding. Microchannels in the top and bottom pieces were aligned with through-holes in the middle layer, resulting in microchannels that cross one another. No discernible delamination of the layers or leakage between channels was observed at pressures as high as 300 psi. The current versus voltage linearity in the crossover channel indicates that no Joule heating occurs at voltages of at least 2.0 kV. Moreover, a potential in the crossover channel did not affect the current in the separation channel. Rapid and efficient separation of fluorescently labeled amino acids was performed in these devices. Pressurized buffer flow or voltage applied in the crossover channel caused no leakage into or electrical interference with the separation channel. Our results demonstrate that sacrificial layers with solvent bonding can be implemented readily in the fabrication of robust and fluidically complex multilayer polymer microchips. These capabilities should facilitate the development of a new generation of sophisticated microfluidic systems.  (+info)

Accidental paraffin poisoning in Kenyan children. (58/216)

 (+info)

Automated FISH analysis using dual-fusion and break-apart probes on paraffin-embedded tissue sections. (59/216)

 (+info)

PCR amplification from paraffin-embedded tissues: recommendations on fixatives for long-term storage and prospective studies. (60/216)

The development of polymerase chain reaction (PCR) DNA amplification methods has afforded molecular studies of fixed paraffin-embedded tissue samples and other archival material. Some fixation methods damage DNA, and thus deleteriously affect subsequent PCR analysis. This study addressed the effect of short- and long-term storage (2 hr to 30 days) in a variety of fixatives (10% buffered-neutral formalin [BNF], 95% ethanol, acetone, and OmniFix) before paraffin embedding. We tested the ability of prepared tissue sections to yield DNA amplification products ranging from 268 to 1327 bp. Results indicated that tissues fixed for 8 days in BNF were able to amplify 536-bp but very little 989-bp DNA fragments; after 30 days of BNF fixation only a 268-bp fragment was amplifiable. Samples fixed in OmniFix and acetone yielded products of 989 and 1327 bp, respectively, after 8 days of fixation; both fixatives yielded 989-bp amplification products after 30 days of fixation. Tissues fixed in 95% ethanol for up to 30 days efficiently produced DNA amplification fragments of up to 1327 bp in length. The results provide important information for prospective studies that involve PCR analysis from archival material. Furthermore, fixation and long-term storage in ethanol should prove particularly useful in remote areas where refrigeration or immediate sample-processing is unavailable.  (+info)

Gene expression predicts overall survival in paraffin-embedded tissues of diffuse large B-cell lymphoma treated with R-CHOP. (61/216)

 (+info)

National Mesothelioma Virtual Bank: a standard based biospecimen and clinical data resource to enhance translational research. (62/216)

 (+info)

Immunohistological diagnosis of "plasmacytoid T cell lymphoma" in paraffin wax sections. (63/216)

An immunohistological study of paraffin wax embedded tissue from three cases of plasmacytoid monocyte neoplasms, using a panel of antibodies which react with fixation resistant leucocyte markers, is reported. This neoplasm was found to have a distinctive antigenic profile, being negative for CD3 and elastase, but positive for CD43 and CD68. This immunological phenotype, coupled with its characteristic morphological features, should facilitate the recognition of this rare neoplasm in routinely processed tissue. Furthermore, the term "plasmacytoid monocyte sarcoma" is proposed to designate it because it is inappropriate to refer to it as a lymphoma. As all cases have been associated with a myeloproliferative disorder (usually an acute or chronic myeloid leukaemia), these tumours probably represent the accumulation in lymphoid tissue of neoplastic cells which have differentiated along the plasmacytoid monocyte pathway.  (+info)

Breslow thickness of cutaneous malignant melanoma in paraffin wax and frozen sections. (64/216)

Breslow tumour thickness was measured in frozen and paraffin wax sections from 21 excision biopsies of cutaneous malignant melanomas by two observers. There was no consistent variation between frozen and paraffin wax sections, with recorded differences ranging from +0.3 mm to -0.2 mm. Interobserver differences ranged from +0.4 mm to -0.2 mm. The interobserver variations exceeded the intraobserver variations, but neither were significant. These findings show conclusively that, when using high quality frozen sections, there is no significant difference between Breslow thickness measured in frozen or paraffin wax sections and therefore that frozen sections can be used to microstage melanoma. Interobserver variations seem to be a more likely source of erroneous measurements of tumour thickness.  (+info)