Intrathoracic negative pressure therapy for pleural empyema using an open-pore drainage film.

BACKGROUND: We report our initial experience with intrathoracic negative pressure therapy (ITNPT) in the stage-adjusted treatment of pleural empyema (PE) based on a case series. MATERIALS AND METHODS: ITNPT represents a further development for intrathoracic use. After thoracic surgical open debridement, an intrathoracic negative pressure dressing was inserted. The drainage elements were a thin open-pore double-layer drainage film (OF) with open-pore polyurethane foams (PUF). Only the OF was placed in direct contact with the lung parenchyma. Negative pressure was generated using an electronic pump (continuous suction, -75 mm Hg). In revision thoracotomies, ITNPT was stopped or continued depending on local findings. RESULTS: In total, 31 patients with stage II and III pleural empyema underwent ITNPT, which was administered during the primary procedure (n = 17) or at revision (n = 14). Treatment duration was a mean of 10 days (2-18 days) with a mean change interval of 4 days (2-6 days). Intrathoracic negative pressure dressings were applied a mean of 3.5 (1-6) times. The empyema cavity continuously reduced in size and was cleansed by the suction. The OF has a minimum intrinsic volume with maximum absorption surface. Once negative pressure is established, there is no intrathoracic dead volume and the parenchyma can expand. The protective material properties of OF make ITNPT suitable for the treatment of pleural empyema. Targeted local intrathoracic drainage of the septic focus is a possible adjunct to surgery. The surgical dressings must be changed repeatedly. The method is suitable for the treatment of complex stage II and III pleural empyemas. CONCLUSION: The OF can be used as an intrathoracic drainage element for ITNPT in pleural empyema. This new application option expands the range of indications for negative pressure therapy.

Wave packet dynamics in the optimal superadiabatic approximation.

We explain the concept of superadiabatic representations and show how in the context of electronically non-adiabatic transitions they lead to an explicit formula that can be used to predict transitions at avoided crossings. Based on this formula, we present a simple method for computing wave packet dynamics across avoided crossings. Only knowledge of the adiabatic potential energy surfaces near the avoided crossing is required for the computation. In particular, this means that no diabatization procedure is necessary, the adiabatic electronic energies can be computed on the fly, and they only need to be computed to higher accuracy when an avoided crossing is detected. We test the quality of our method on the paradigmatic example of photo-dissociation of NaI, finding very good agreement with results of exact wave packet calculations.

Use of genetically modified muscle and fat grafts to repair defects in bone and cartilage.

We report a novel technology for the rapid healing of large osseous and chondral defects, based upon the genetic modification of autologous skeletal muscle and fat grafts. These tissues were selected because they not only possess mesenchymal progenitor cells and scaffolding properties, but also can be biopsied, genetically modified and returned to the patient in a single operative session. First generation adenovirus vector carrying cDNA encoding human bone morphogenetic protein-2 (Ad.BMP-2) was used for gene transfer to biopsies of muscle and fat. To assess bone healing, the genetically modified ("gene activated") tissues were implanted into 5mm-long critical size, mid-diaphyseal, stabilized defects in the femora of Fischer rats. Unlike control defects, those receiving gene-activated muscle underwent rapid healing, with evidence of radiologic bridging as early as 10 days after implantation and restoration of full mechanical strength by 8 weeks. Histologic analysis suggests that the grafts rapidly differentiated into cartilage, followed by efficient endochondral ossification. Fluorescence in situ hybridization detection of Y-chromosomes following the transfer of male donor muscle into female rats demonstrated that at least some of the osteoblasts of the healed bone were derived from donor muscle. Gene activated fat also healed critical sized defects, but less quickly than muscle and with more variability. Anti-adenovirus antibodies were not detected. Pilot studies in a rabbit osteochondral defect model demonstrated the promise of this technology for healing cartilage defects. Further development of these methods should provide ways to heal bone and cartilage more expeditiously, and at lower cost, than is presently possible.

Delayed administration of adenoviral BMP-2 vector improves the formation of bone in osseous defects.

The direct, local, administration of adenovirus carrying human BMP-2 cDNA (Ad.BMP-2) heals critical-sized femoral bone defects in rabbit and rat models. However, the outcome is suboptimal and the technology needs to provide a more reliable and uniform outcome. To this end, we investigated whether the timing of Ad.BMP-2 administration influenced the formation of mineralized tissue within the defect. Critical-sized defects were created in the femora of 28 Sprague-Dawley rats. Animals were injected intralesionally with a single, percutaneous injection of Ad.BMP-2 (4 x 10(8) plaque-forming units) either intraoperatively (day 0) or 24 h (day 1), 5 days or 10 days after surgery. The femora were evaluated 8 weeks after surgery by X-ray, microcomputed tomography, dual-energy X-ray absorptiometry and biomechanical testing. The incidence of radiological union was markedly increased when administration of Ad.BMP-2 was delayed until days 5 and 10, at which point 86% of the defects healed. These time points also provided greater bone mineral content within the defect site and improved the average mechanical strength of the healed bone. Thus, delaying the injection of Ad.BMP-2 until 5 or 10 days after surgery enables a greater percentage of critical-sized, segmental defects to achieve radiological union, producing a repair tissue with enhanced mineralization and greater mechanical strength.

Immunocytochemical detection of Ig-positive cells in blood, lymphoid organs and the gut associated lymphoid tissue of the turbot (Scophthalmus maximus).

The present study was designed to search for the sites of the B-cell lineage in the different lymphoid organs of turbot (Scophthalmus maximus) by immunoperoxidase staining with a rabbit polyclonal antiserum against deglycosylated turbot IgM (TUDG-6). A turbot immunoglobulin (Ig) fraction, isolated by protein A, was checked for purity by gel filtration and SDS-PAGE under reducing conditions. The turbot IgM was deglycosylated and used to raise an antiserum. The antiserum titre was evaluated in ELISA. It was then used to analyse turbot peripheral blood leucocytes for membrane and cytoplasmic Ig and for immunohistochemistry with turbot lymphoid tissues. Very low numbers of Ig+ cells were found in thymus sections. In sections of spleen, Ig+ cells were observed in white pulp, around ellipsoids but were mostly concentrated and associated with melanomacrophage centers (MMCs). The lymphoid Ig+ cells in the kidney tended to be dispersed among haematopoietic and granulopoietic cell populations and were in intimate association with the MMCs and blood vessels. This association between MMCs and Ig+ cells in the spleen and the kidney, is discussed with respect to the role played by these organs in the immune system of fish. Last, the lymphoid population in the gut associated lymphoid tissue (GALT) of turbot was characterised with respect to staining for Ig. Immunoreactive cells were rarely detected in the epithelial layer although many lymphocytes were present, but they were frequently observed in the lamina propria, presumably as part of the GALT and involved in mucosal immune responses.