Bilateral skin fold rotation-advancement flaps for the closure of large lumbosacral wounds in three dogs

Three dogs were presented for the management of disease processes resulting in large skin defects over the dorsal lumbosacral region. One had severe dog bite wounds, one had a large burn sustained from a heating pad and one had a large myxosarcoma in the region. In each case, the extent and location of the resulting skin defect were assessed as factors likely to prevent reconstruction using simple tension-relieving techniques alone or in combination with established reconstructive techniques, such as axial pattern flaps or skin stretching devices. Bilateral skin fold rotation-advancement flaps (SFRAFs) based on the flank folds were mobilised dorsally and allowed complete wound closure in two dogs and subtotal closure in the other dog. All wounds healed without major complications and an acceptable cosmetic outcome was achieved in each case. Minor flap debridement was required in two dogs. The use of bilateral SFRAFs is a useful technique alone or in combination with other reconstructive techniques for the closure of large dorsal lumbosacral skin defects when existing techniques are not sufficient. Small flank folds, such as those of obese dogs, may yield unexpectedly large SFRAFs.

The use of the cemented Exeter Universal femoral stem in a District General Hospital

We describe the survivorship of the Exeter femoral component in a District General Hospital. Between 1994 and 1996, 230 Exeter Universal cemented femoral components were implanted in 215 patients who were reviewed at a mean of 11.2 years (10 to 13). We used one acetabular implant, the Elite Ogee component, in 218 of the 230 hips.

During the period of this study 76 patients (79 hips) died. Of the remaining 139 patients (151 hips), 121 were able to attend for radiological analysis at a minimum of ten years. One patient was lost to follow-up.

No femoral component was revised for aseptic loosening. Three hips were revised for deep infection and six acetabular components required revision, four for loosening and two for recurrent dislocation. Taking the ‘worst-case scenario’ including the one patient lost to follow-up, the overall survival rate was 94.4% at 13 years.

Our results confirm excellent medium-term results for the Exeter Universal femoral component, implanted in a general setting. The excellent survival of this femoral component, when used in combination with the Ogee acetabular component, suggests that this is a successful pairing.

The Role of the Kidney in Blood Volume Regulation: The Kidney as a Regulator of the Hematocrit

The kidney plays a pivotal role in the regulation of blood volume by controlling the plasma volume and red blood cell (RBC) mass. Further, it is proposed that the kidney coordinates the relative volumes of these 2 blood components and in so doing regulates the hematocrit. This novel function as proposed is a functional concept whereby the kidney does not simply produce erythropoietin, but that the kidney regulates the hematocrit is termed the critmeter function. The kidney is unique in that it can indirectly report on blood volume as a tissue oxygen signal. It is proposed that the kidneys detect small changes in tissue oxygen tension for erythropoietin production at the critmeter, a functional unit of marginal oxygen tension within the kidneys. As the production of erythropoietin is modulated by angiotensin II, the renin-angiotensin system entrains the production of erythropoietin as part of the effector signals of the feedback loop of blood volume regulation. Collectively, the consideration of these points generates a paradigm shift in our understanding of blood volume regulation in that the role of the kidney may be expanded from simply "producing" erythropoietin to regulating the hematocrit. Further, this concept broadens the scope of the traditionally identified effector mechanisms of plasma volume regulation to include the modulation of erythropoietin production and hence RBC mass. The inclusion of both plasma volume and RBC mass as factors targeted by the effector signals recapitulates that whole blood volume is sensed and reported in the afferent signals. In summary, distinct sensing and effector mechanisms for regulating the volume of the two components of whole blood (plasma and red cell mass) are recognized. The coupling of the regulation of these 2 components of blood volume is highlighted.

Prevention and treatment of musculoskeletal disease in the haemophilia population: role of prophylaxis and synovectomy

Prophylaxis is defined as primary (started before the onset of joint damage) or secondary (started after the onset of joint damage). The aim of primary prophylaxis is to prevent recurrent bleeding into joints and the development of chronic arthropathy in later life. When started early, and at most after two joint bleeds, the result is predictably excellent if there is compliance with the primary prophylaxis regimen. In order to decrease the need for central venous access devices to assure reliable venous access, a number of centres start primary prophylaxis with once weekly infusions with dose-escalation based on frequency of joint bleeding. A major unanswered question is whether primary prophylaxis can be safely discontinued in adolescents/young adults and if so, when. A promising predictor for the milder bleeding phenotype in persons with severe haemophilia is a later onset of joint bleeding. Once joint damage has occurred as a result of recurrent bleeding, secondary prophylaxis can only retard, but not prevent, ongoing joint damage. Other strategies to decrease recurrent bleeding from target joints include surgical synovectomy (ideally performed using an arthroscopic technique), radionuclide synovectomy and chemical synovectomy. These interventions have very good outcomes when performed by an experienced team. Given the very high cost of factor concentrates required for programmes of prophylaxis prospective studies that document benefits to the child and family, e.g. quality of life are to be encouraged.

Cytokine-mediated deployment of SDF-1 induces revascularization through recruitment of CXCR4+ hemangiocytes

The mechanisms through which hematopoietic cytokines accelerate revascularization are unknown. Here, we show that the magnitude of cytokine-mediated release of SDF-1 from platelets and the recruitment of nonendothelial CXCR4+ VEGFR1+ hematopoietic progenitors, 'hemangiocytes,' constitute the major determinant of revascularization. Soluble Kit-ligand (sKitL), thrombopoietin (TPO, encoded by Thpo) and, to a lesser extent, erythropoietin (EPO) and granulocyte-macrophage colony-stimulating factor (GM-CSF) induced the release of SDF-1 from platelets, enhancing neovascularization through mobilization of CXCR4+ VEGFR1+ hemangiocytes. Although revascularization of ischemic hindlimbs was partially diminished in mice deficient in both GM-CSF and G-CSF (Csf2-/- Csf3-/-), profound impairment in neovascularization was detected in sKitL-deficient Mmp9-/- as well as thrombocytopenic Thpo-/- and TPO receptor-deficient (Mpl-/-) mice. SDF-1-mediated mobilization and incorporation of hemangiocytes into ischemic limbs were impaired in Thpo-/-, Mpl-/- and Mmp9-/- mice. Transplantation of CXCR4+ VEGFR1+ hemangiocytes into Mmp9-/- mice restored revascularization, whereas inhibition of CXCR4 abrogated cytokine- and VEGF-A-mediated mobilization of CXCR4+ VEGFR1+ cells and suppressed angiogenesis. In conclusion, hematopoietic cytokines, through graded deployment of SDF-1 from platelets, support mobilization and recruitment of CXCR4+ VEGFR1+ hemangiocytes, whereas VEGFR1 is essential for their angiogenic competency for augmenting revascularization. Delivery of SDF-1 may be effective in restoring angiogenesis in individuals with vasculopathies.

Complete genome sequence of Vibrio fischeri: a symbiotic bacterium with pathogenic congeners

Vibrio fischeri belongs to the Vibrionaceae, a large family of marine gamma-proteobacteria that includes several dozen species known to engage in a diversity of beneficial or pathogenic interactions with animal tissue. Among the small number of pathogenic Vibrio species that cause human diseases are Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus, the only members of the Vibrionaceae that have had their genome sequences reported. Nonpathogenic members of the genus Vibrio, including a number of beneficial symbionts, make up the majority of the Vibrionaceae, but none of these species has been similarly examined. Here we report the genome sequence of V. fischeri ES114, which enters into a mutualistic symbiosis in the light organ of the bobtail squid, Euprymna scolopes. Analysis of this sequence has revealed surprising parallels with V. cholerae and other pathogens.

Threshold effects of glucose transporter-4 (GLUT4) deficiency on cardiac glucose uptake and development of hypertrophy

The aim of this study was to investigate the metabolic and structural consequences of a decrease in glucose transporter-4 (GLUT4) levels on the heart. The CreLoxP system was utilised to delete GLUT4 in muscle tIssue including heart. The presence of the PGK-neoR cassette in the GLUT4-Lox mice resulted in reduced expression in all tIssues to levels 15-30% of wild-type control mice. In mice expressing Cre recombinase, there was a further reduction of GLUT4 in cardiac tIssue to almost undetectable levels. Cardiac glucose uptake was measured basally and during a euglycaemic/hyperinsulinaemic clamp using 2-deoxy-[1-(14)C]glucose. Insulin-stimulated glucose uptake was normal in hearts expressing 15% of normal GLUT4 levels but markedly reduced in mice with more profound reduction in GLUT4. Cardiac enlargement occurred only when GLUT4 levels were less than 5% of normal values. In heart there is a threshold level of GLUT4 above which insulin-stimulated glucose uptake is maintained. As little as 5% of normal GLUT4 levels expressed in heart is sufficient to prevent the development of cardiac hypertrophy.

G-CSF: function and modes of action (Review)

Since the observations in the 1960s that granulocyte-colony stimulating factor (G-CSF) stimulated the proliferation of granulocytic cells in semisolid cultures of bone marrow cells, G-CSF has established itself as a useful clinical agent for increasing levels of neutrophilic granulocytes. However, these early findings did not firmly establish whether G-CSF is a genuine regulator of granulocyte formation under normal physiological conditions or rather acts as an emergency regulator, playing an important role only under stress conditions. The advent of <gene-knockout technology> has allowed us to evaluate these questions in a physiological setting through analysis of mice with a targeted mutation of G-CSF or its receptor, while the development of relevant cell models has enabled us to dissect the molecular basis of G-CSF action. This review discusses our current state of knowledge regarding the role of G-CSF in granulopoiesis.

Three dimensional Monte Carlo code for photon migration through complex heterogeneous media including the adult human head

We describe a novel Monte Carlo code for photon migration through 3D media with spatially varying optical properties. The code is validated against analytic solutions of the photon diffusion equation for semi-infinite homogeneous media. The code is also cross-validated for photon migration through a slab with an absorbing heterogeneity. A demonstration of the utility of the code is provided by showing time-resolved photon migration through a human head. This code, known as 'tMCimg', is available on the web and can serve as a resource for solving the forward problem for complex 3D structural data obtained by MRI or CT.

Clinical trials update: Highlights of the Scientific Sessions of Heart Failure 2001, a meeting of the Working Group on Heart Failure of the European Society of Cardiology. CONTAK-CD, CHRISTMAS, OPTIME-CHF

This article continues a series of reports summarising recent research developments pertinent to the topic of heart failure. This is a summary of presentations made at Scientific Sessions of Heart Failure 2001, a meeting of the Working Group on Heart Failure of the European Society of Cardiology. Clinical studies of particular interest to people caring for patients with heart failure include CONTAK-CD, CHRISTMAS and further updates on OPTIME-CHF. A brief review of the current status of cardiac resynchronisation therapy is included.