Vacuum-Assisted Therapy for Combined Volar-Dorsal Soft-Tissue Defects of the Hand: A Case Report

ABSTRACT

Application of negative-pressure wound therapy dressings to the web spaces and small, often moist, areas of the hand can be technically demanding and time consuming. The researchers present a case report and technique for managing a devastating hand infection and soft-tissue defects by creating a self-fabricated sponge glove that is easily reproducible. Vacuum-assisted therapy for combined volar dorsal soft-tissue defects of the hand, or "Hand Vac," is a novel approach for treating extensive hand wounds. This technique was used in a patient with diabetes with a deep space infection of the hand following serial debridements and antibiotic bead therapy. A single, medium-size sponge was cut using a knife and scissors to create an easily applied glove that was then sealed with adhesive dressing and a single suction port. The patient avoided complete amputation of the hand and deep infection was eradicated. The wounds had progressive granulation and healing and were eventually covered with split-thickness skin grafts. The authors conclude that severe soft-tissue defects involving both the volar and dorsal aspects of the hand can be effectively managed with a single glove-like sponge and suction port.

Fragility Fractures of the Pelvis and Sacrum: Current Trends in Literature

Fragility fractures of the pelvis (FFP) and fragility fractures of the sacrum (FFS), which are emerging in the geriatric population, exhibit characteristics that differ from those of pelvic ring disruptions occurring in the younger population. Treatment of FFP/FFS by a multidisciplinary team can be helpful in reducing morbidity and mortality with the goal of reducing pain, regaining early mobility, and restoring independence for activities of daily living. Conservative treatment, including bed rest, pain therapy, and mobilization as tolerated, is indicated for treatment of FFP type I and type II as loss of stability is limited with these fractures. Operative treatment is indicated for FFP type II when conservative treatment has failed and for FFP type III and type IV, which are displaced fractures associated with intense pain and increased instability. Minimally invasive stabilization techniques, such as percutaneous fixation, are favored over open reduction internal fixation. There is little evidence regarding outcomes of patients with FFP/FFS and more literature is needed for determination of optimal management. The aim of this article is to provide a concise review of the current literature and a discussion of the latest recommendations for orthopedic treatment and management of FFP/FFS.

Pilon Fractures: Challenges and Solutions

Pilon fractures include a wide range of complexity. The timing and type of definitive fixation is dictated by the soft tissue injury and energy imparted to the fracture. One should have a low threshold for staged protocols and delayed definitive fixation to avoid complications. Proper radiographs and advanced imaging should be obtained for an exacting diagnosis and preoperative planning. Diligent management of the soft tissue and anatomic restoration of the articular surface, length, rotation, and axial alignment with stable fixation to the diaphysis should be obtained once feasible. Intramedullary implants with percutaneous articular fixation for simple or extra-articular patterns provide good results with little soft tissue insult in the zone of injury. Minimally invasive plate osteosynthesis techniques can help mitigate some concerns with soft tissue compromise while obtaining good articular alignment. Locking or conventional plating with lag screw fixation is used for complex articular injuries with or without fibular fixation. External fixators are generally used for temporizing measures but can be utilized as definitive fixation when indicated. There is a role for acute fusion in severely comminuted, osteoporotic, or arthritic fractures in patients with poor healing potential. This article outlines the diagnostic workup and treatment of these vexing injuries with solutions to challenges that arise.

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Development and validation of a phosphorylated SMAD ex vivo stimulation assay

Assessing the pharmacodynamics (PD) of a potential therapeutic through the use of a downstream biomarker is essential. This is traditionally performed in the target tissue but limited volume and invasiveness of sampling pose challenges with solid tumours. Currently, there are several small molecule receptor kinase inhibitors and large molecule therapeutic antibodies in clinical trials that interfere with TGFbeta signalling to treat various forms of cancer. With the advent of these new therapies, there is a need for a surrogate tissue that is easily accessible and indicative of tumour response. We propose the use of an ex vivo TGFbeta1 stimulation of peripheral blood mononuclear cells (PBMCs) coupled with the measurement of phosphorylated SMAD2 (Sma/Mothers Against dpp, a downstream transcriptional activator) using a sandwich ELISA. TGFbeta is involved in many different cellular responses, such as proliferation, angiogenesis, migration, invasion and immunomodulation. SMAD2 and SMAD3 are phosphorylated as a result of the canonical cascade through ligand binding and receptor kinase activation. These phosphorylated SMADs (pSMAD) associate with SMAD4, a co-SMAD, and transcriptionally activate TGFbeta-mediated genes. This paper describes the novel method for measuring the downstream effects of inhibiting canonical TGFbeta signalling using ex vivo stimulation of surrogate tissue to predict tumour response. In addition, we present the assay validation rationale and data. This novel, validated assay can be used to gain insight into clinical trials regarding TGFbeta signal modulation by multiple inhibitor platforms for both large and small molecules.

Activated type I TGFbeta receptor kinase enhances the survival of mammary epithelial cells and accelerates tumor progression

We have examined the effects of transforming growth factor-beta (TGFbeta) signaling on mammary epithelial cell survival. Transgenic mice expressing an active mutant of Alk5 in the mammary gland (MMTV-Alk5(T204D)) exhibited reduced apoptosis in terminal endbuds and during postlactational involution. Transgene-expressing mammary cells contained lower Smad2/3 and higher c-myc levels than controls, high ligand-independent phosphatidylinositol-3 kinase (PI3K) and Akt activities, and were insensitive to TGFbeta-mediated growth arrest. Treatment with a proteasome inhibitor increased Smad2/3 levels and ligand-independent Smad transcriptional reporter activity, as well as reduced both c-myc protein and basal cell proliferation. Treatment with an Alk5 kinase small-molecule inhibitor upregulated Smad2/3 levels, reduced PI3K activity, P-Akt, and c-myc, and inhibited cell survival. Although Alk5(T204D)-expressing mice did not develop mammary tumors, bigenic MMTV-Alk(T204D) x Neu mice developed cancers that were more metastatic than those occurring in MMTV-Neu transgenics. These data suggest that (1) TGFbeta can signal to PI3K/Akt and enhance mammary epithelial cell survival in vivo before cytological or histological evidence of transformation, and (2) TGFbeta signaling can provide epithelial cells with a 'gain-of-function' effect that synergizes with oncogene-induced transformation.

Bmp signaling regulates proximal-distal differentiation of endoderm in mouse lung development

In the mature mouse lung, the proximal-distal (P-D) axis is delineated by two distinct epithelial subpopulations: the proximal bronchiolar epithelium and the distal respiratory epithelium. Little is known about the signaling molecules that pattern the lung along the P-D axis. One candidate is Bone Morphogenetic Protein 4 (Bmp4), which is expressed in a dynamic pattern in the epithelial cells in the tips of growing lung buds. Previous studies in which Bmp4 was overexpressed in the lung endoderm (Bellusci, S., Henderson, R., Winnier, G., Oikawa, T. and Hogan, B. L. M. (1996) Development 122, 1693–1702) suggested that this factor plays an important role in lung morphogenesis. To further investigate this question, two complementary approaches were utilized to inhibit Bmp signaling in vivo. The Bmp antagonist Xnoggin and, independently, a dominant negative Bmp receptor (dnAlk6), were overexpressed using the surfactant protein C (Sp-C) promoter/enhancer. Inhibiting Bmp signaling results in a severe reduction in distal epithelial cell types and a concurrent increase in proximal cell types, as indicated by morphology and expression of marker genes, including the proximally expressed hepatocyte nuclear factor/forkhead homologue 4 (Hfh4) and Clara cell marker CC10, and the distal marker Sp-C. In addition, electron microscopy demonstrates the presence of ciliated cells, a proximal cell type, in the most peripheral regions of the transgenic lungs. We propose a model in which Bmp4 is a component of an apical signaling center controlling P-D patterning. Endodermal cells at the periphery of the lung, which are exposed to high levels of Bmp4, maintain or adopt a distal character, while cells receiving little or no Bmp4 signal initiate a proximal differentiation program.

Epithelial/mesenchymal interactions and branching morphogenesis of the lung

The establishment of branched tubular epithelial structures is critical for the viability of multicellular organisms: the tracheal system in Drosophila and the vertebrate lung being two such structures. Although there are obvious differences in the complexity of these branched organs, many of the underlying mechanisms and genes regulating their development appear to have been evolutionarily conserved.

Tumor suppressor Smad4 is a transforming growth factor beta-inducible DNA binding protein

Members of the Smad family of proteins are thought to play important roles in transforming growth factor beta (TGF-beta)-mediated signal transduction. In response to TGF-beta, specific Smads become inducibly phosphorylated, form heteromers with Smad4, and undergo nuclear accumulation. In addition, overexpression of specific Smad combinations can mimic the transcriptional effect of TGF-beta on both the plasminogen activator inhibitor 1 (PAI-1) promoter and the reporter construct p3TP-Lux. Although these data suggest a role for Smads in regulating transcription, the precise nuclear function of these heteromeric Smad complexes remains largely unknown. Here we show that in Mv1Lu cells Smad3 and Smad4 form a TGF-beta-induced, phosphorylation-dependent, DNA binding complex that specifically recognizes a bipartite binding site within p3TP-Lux. Furthermore, we demonstrate that Smad4 itself is a DNA binding protein which recognizes the same sequence. Interestingly, mutations which eliminate the Smad DNA binding site do not interfere with either TGF-beta-dependent transcriptional activation or activation by Smad3/Smad4 cooverexpression. In contrast, mutation of adjacent AP1 sites within this context eliminates both TGF-beta-dependent transcriptional activation and activation in response to Smad3/Smad4 cooverexpression. Furthermore, concatemerized AP1 sites, in isolation, are activated by Smad3/Smad4 cooverexpression and, to a certain extent, by TGF-beta. Taken together, these data suggest that the Smad3/Smad4 complex has at least two separable nuclear functions: it forms a rapid, yet transient sequence-specific DNA binding complex, and it potentiates AP1-dependent transcriptional activation.

Smad5 induces ventral fates in Xenopus embryo

The Smad proteins have been implicated in the intracellular signaling of transforming growth factor-beta (TGF-beta) ligands. Here we describe the function of Smad5 in early Xenopus development. Misexpression of Smad5 in the embryo causes ventralization and induces ventral mesoderm. Moreover, Smad5 induces epidermis in dissociated ectoderm cells which would otherwise form neural tissue. Both of these activities require Smad4 (DPC4) activity. We propose that Smad5 acts downstream of the BMP4 signaling pathway in Xenopus embryos and directs the formation of ventral mesoderm and epidermis.

Mammalian dwarfins are phosphorylated in response to transforming growth factor beta and are implicated in control of cell growth

The dwarfin protein family has been genetically implicated in transforming growth factor beta (TGF-beta)-like signaling pathways in Drosophila and Caenorhabditis elegans. To investigate the role of these proteins in mammalian signaling pathways, we have isolated and studied two murine dwarfins, dwarfin-A and dwarfin-C. Using antibodies against dwarfin-A and dwarfin-C, we show that these two dwarfins and an immunogenically related protein, presumably also a dwarfin, are phosphorylated in a time- and dose-dependent manner in response to TGF-beta. Bone morphogenetic protein 2, a TGF-beta superfamily ligand, induces phosphorylation of only the related dwarfin protein. Thus, TGF-beta superfamily members may use overlapping yet distinct dwarfins to mediate their intracellular signals. Furthermore, transient overexpression of either dwarfin-A or dwarfin-C causes growth arrest, implicating the dwarfins in growth regulation. This work provides strong biochemical and preliminary functional evidence that dwarfin-A and dwarfin-C represent prototypic members of a family of mammalian proteins that may serve as mediators of signaling pathways for TGF-beta superfamily members.

A transforming growth factor beta type I receptor that signals to activate gene expression

Transforming growth factor beta (TGF-beta) is a multifunctional factor that regulates many aspects of cellular functions. TGF-beta signals through a heteromeric complex of the type I and type II TGF-beta receptors. However, the molecular mechanism of signal transduction by this receptor complex remains unresolved. The type II receptor belongs to a transmembrane receptor serine-threonine kinase family. A new member of this receptor family (R4) was identified and shown to be a functional TGF-beta type I receptor on the basis of its ability to restore a TGF-beta-induced gene response in mutant cell lines lacking endogenous type I receptor. Both ligand binding and signaling of the R4 protein were dependent on the presence of a functional type II receptor. The type I receptor has an intrinsic serine-threonine kinase activity, which was essential for signal transduction.

Antiproliferative effects of interferons -alpha and -beta in combination with 5-fluorouracil, cisplatin, and cis- and trans-retinoic acid in three human lung carcinoma cell lines

We assessed the antiproliferative effect of human recombinant interferon -alpha (IFN-alpha) or -beta in combination with 5-fluorouracil (5-FU), cisplatin, or cis- or trans-retinoic acid on two human nonsmall cell lung carcinoma cell lines (SK-LU-1 and SK-MES-1) and on one human small cell lung carcinoma cell line (NCI-H69). Results were obtained by direct cell count and/or by the clonigenic assay. The three cell lines differed in their sensitivities to the antiproliferative effects of the different agents. However, both NSCLC cell lines were more responsive to IFN-beta than to IFN-alpha. The SK-MES cell line was more resistant to both IFNs than the SK-LU-1. The NCI-H69 cells were resistant to all the drugs tested, except trans-retinoic acid. The dose and time of exposure were found to be important factors in the case of IFNs and cytotoxic agents, with lower surviving fractions obtained with the higher doses and longer exposures. This finding, however, did not hold true for the retinoic acids, which showed no antiproliferative effect. Within the sensitivity of our system, we did not identify any synergistic interaction in any of the cell lines with IFN-alpha or IFN-beta and 5-FU or cisplatin. A slight synergistic interaction was observed with IFN and cis- or trans-retinoic acid in the SK-LU-1 cell line which was not thought to be clinically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

An estrogen receptor positive MCF-7 clone that is resistant to antiestrogens and estradiol

The antiestrogen tamoxifen has been successfully used to control estrogen receptor (ER) and progesterone receptor positive breast cancer. However, the development of antiestrogen resistance is frequently observed in patients following long term treatment. We have studied the development of antiestrogen resistance in vitro and established an antiestrogen resistant variant of MCF-7 cells (clone 5C) after long term culture in estrogen free medium. The growth of clone 5C cells was not altered by either estradiol-17 beta or the antiestrogens 4-hydroxytamoxifen and ICI 164,384. Estrogen-stimulated progesterone receptor and reporter gene expression were markedly reduced in 5C cells compared to wild type MCF-7 cells. Only minor alteration in the levels of ER and no alteration in the affinity of ER for ligand were found in 5C cells. No mutation of ER cDNA in 5C cells was detected by polymerase chain reaction and DNA sequencing. This study demonstrates that change(s) in ER-mediated gene expression rather than the amino acid sequence of the ER itself may be associated with the development of at least one form of antiestrogen resistance.