Multifunctional, Micropipette-based Method for Incorporation And Stimulation of Bacterial Mechanosensitive Ion Channels in Droplet Interface Bilayers

MscL, a large conductance mechanosensitive channel (MSC), is a ubiquitous osmolyte release valve that helps bacteria survive abrupt hypo-osmotic shocks. ...

Virginia Polytechnic Institute and State University

To evaluate ultrasonography (US)-guided core biopsy in the assessment of 247 patients with cervicofacial lymphadenopathy.

Head and neck lymphadenopathy: evaluation with US-guided cutting-needle biopsy.

To evaluate safety, yield, and accuracy of ultrasonography (US)-guided core-needle biopsy of the thyroid gland.

US-guided core-needle biopsy of the thyroid gland.

Recommended first-line treatment for posttransplant lymphoproliferative disorder (PTLD) is reduction in immunosuppressive therapy, irrespective of histopathological type. Second-line treatment with chemotherapy is generally reserved for tumors that fail to respond to reduced immunosuppression. In view of the similarities between monomorphic PTLD and non-Hodgkin's lymphoma in the general population, our policy is to treat monomorphic PTLD with anthracycline-based chemotherapy as first-line treatment.

Anthracycline-based chemotherapy as first-line treatment in adults with malignant posttransplant lymphoproliferative disorder after solid organ transplantation.

We report an unusual occurrence of spontaneous pigmentary regression with a desmoplastic reaction in a neonatally eroded giant congenital melanocytic nevus. This process has been documented with photographs and skin biopsy specimens. Neonatal histology demonstrated connective tissue proliferation. Histology at age 5 years also demonstrated a very high proportion of amelanotic dermal nevus cells. Regression of pigmentation in our patient may be due to a decrease in melanin production by dermal nevus cells rather than a decrease in their number.

Clinical resolution of a neonatally eroded giant congenital melanocytic nevus.

BIOMED-2 polymerase chain reaction (PCR) assays for clonality analysis of immunoglobulin (IG) and T-cell receptor (TCR) gene rearrangements were evaluated in routine haematopathological practice where paraffin-embedded tissues constitute the majority of specimens. One hundred and twenty-five fresh/frozen and 316 paraffin specimens were analysed for DNA quality and clonality. Seventy-nine per cent of paraffin specimens yielded PCR products of over 300 bp. These specimens and all fresh/frozen specimens were analysed with the complete set of BIOMED-2 reactions for IG (8 reactions) and/or TCR (6 reactions) gene rearrangements. The rate of detection of clonality was 96% in mature B-cell neoplasms and 98% in mature T-cell neoplasms and there were no significant differences in these rates between paraffin and fresh/frozen specimens. As the value of sole use of any individual BIOMED-2 reaction in clonality detection was limited, we assessed combinations of reactions that gave the greatest sensitivity with fewest reactions and were applicable for both fresh/frozen and paraffin specimens. For IG gene rearrangements, three reactions combining one targeting the IG heavy chain framework-2 region and two targeting the IG kappa locus achieved a 91% detection rate. For TCR gene rearrangements, the two TCR gamma reactions gave a 94% detection rate. We therefore recommend this strategy as the first-line assays for routine B- and T-cell clonality analysis in diagnostic haematopathology.

A practical strategy for the routine use of BIOMED-2 PCR assays for detection of B- and T-cell clonality in diagnostic haematopathology.

The aim of this study was to evaluate ultrasound (US)-guided core-needle testicular biopsy. Twelve biopsies were performed in eleven patients, under US guidance using disposable 16- or 18-gauge needles, between April 2003 and October 2006. Details were entered on a database and records reviewed 9 months to 3 years after biopsy. Final diagnoses were based on histology of the biopsy, open surgical resection where performed, and interval follow-up. Biopsies were well tolerated and no complications were encountered apart from a single minor testicular haemorrhage. Benign histology was demonstrated on the core-needle samples of six patients and US follow-up was compatible with these diagnoses. Of five patients whose core-needle biopsies yielded malignancy, two patients had primary testicular tumours; both have been treated successfully with orchiectomy and chemotherapy. Three patients with haematological malignancies had successful chemotherapy without orchiectomy; one of these three underwent post-chemotherapy biopsy demonstrating resolution. There are four main clinical scenarios when core-needle testicular biopsy is performed in our institution: (1) lesions with equivocal malignant US features, (2) discrepancy between radiological and clinical findings, (3) suspected malignant process where orchiectomy is unnecessary, e.g. lymphoma, (4) atrophic testes, where it is frequently difficult to differentiate malignancy from the heterogeneous echo pattern.

Ultrasound-guided core-needle biopsy of the testis for focal indeterminate intratesticular lesions.

B-cell clonality analysis is commonly performed by polymerase chain reaction (PCR) targeting the IGH genes although a high false-negative rate is recognized for germinal centre/post-germinal centre B-cell malignancies, especially follicular lymphoma. We assessed the diagnostic value of BIOMED-2 IGK assays and investigated the cause of IGH PCR failure in 77 patients with follicular lymphoma. Using the full set of BIOMED-2 reactions, clonal immunoglobulin gene rearrangements were detected in 74 (96%) cases. The clonality detection rate was 86% by two IGK reactions but only 68% by five IGH reactions (P < 0·001). Sequencing of the clonal PCR products showed significantly fewer somatic mutations in the rearranged IGKV (9/27 cases, 33%, mean mutation rate 0·5%) than IGHV (17/17 cases, 100%, rate 11·0%) (P < 0·01). All IGHV-IGHJ PCR failures occurred in cases with at least one mutation at the corresponding IGHV primer binding sites. t(14:18)(q32:q21)/IGH-BCL2 was detected in 50 of 71 (70%) cases and the presence of the translocation was not associated with the poor performance of IGH assays. Our results showed that BIOMED-2 IGK assays are significantly more sensitive than IGH assays in follicular lymphoma due to the fact that the rearranged IGKV is less frequently targeted by somatic hypermutation than IGHV, and therefore, are essential in routine clonality analysis of these lymphomas.

BIOMED-2 PCR assays for IGK gene rearrangements are essential for B-cell clonality analysis in follicular lymphoma.

MscL, a stretch-activated channel, saves bacteria experiencing hypo-osmotic shocks from lysis. Its high conductance and controllable activation makes it a strong candidate to serve as a transducer in stimuli-responsive biomolecular materials. Droplet interface bilayers (DIBs), flexible insulating scaffolds for such materials, can be used as a new platform for incorporation and activation of MscL. Here, we report the first reconstitution and activation of the low-threshold V23T mutant of MscL in a DIB as a response to axial compressions of the droplets. Gating occurs near maximum compression of both droplets where tension in the membrane is maximal. The observed 0.1-3 nS conductance levels correspond to the V23T-MscL sub-conductive and fully open states recorded in native bacterial membranes or liposomes. Geometrical analysis of droplets during compression indicates that both contact angle and total area of the water-oil interfaces contribute to the generation of tension in the bilayer. The measured expansion of the interfaces by 2.5% is predicted to generate a 4-6 mN/m tension in the bilayer, just sufficient for gating. This work clarifies the principles of interconversion between bulk and surface forces in the DIB, facilitates the measurements of fundamental membrane properties, and improves our understanding of MscL response to membrane tension.

John W. Grant

Department of Engineering Sciences and Mechanics

Virginia Polytechnic Institute and State University

Multifunctional, Micropipette-based Method for Incorporation And Stimulation of Bacterial Mechanosensitive Ion Channels in Droplet Interface Bilayers

John W. Grant

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Engineering Sciences and Mechanics

Virginia Polytechnic Institute and State University

Multifunctional, Micropipette-based Method for Incorporation And Stimulation of Bacterial Mechanosensitive Ion Channels in Droplet Interface Bilayers

Department of Engineering Sciences and Mechanics