Protein A is the von Willebrand factor binding protein on Staphylococcus aureus

Endovascular infection is a highly critical complication of invasive Staphylococcus aureus disease. For colonization, staphylococci must first adhere to adhesive endovascular foci. Von Willebrand factor (vWF) is a large, multimeric glycoprotein mediating platelet adhesion at sites of endothelial damage. Earlier it was demonstrated that vWF binds to and promotes the surface adhesion of S. aureus, prompting this effort to identify the vWF adhesin. In Western ligand assays of S. aureus lysates, staphylococcal protein A (SPA) was recognized by purified vWF. Surface plasmon resonance demonstrated the binding of soluble vWF to immobilized recombinant protein A with a K(d) of 1.49 x 10(-8) mol/L. Using flow cytometry, the binding of fluorescein isothiocyanate-labeled vWF to S. aureus was found to be saturable and inhibitable by unlabeled vWF, antiprotein-A antibodies, or IgG. Isogenic Deltaspa::Tc(r) mutants were constructed by the insertion of a tetracycline resistance cassette into spa using allelic replacement, and it exhibited decreased binding of soluble vWF and decreased adhesion to vWF-adsorbed surfaces. The interaction was restored on complementation of the mutants with spa-containing plasmid pSPA7235. In conclusion, protein A confers interaction of S. aureus with soluble and immobilized vWF in a newly discovered function characterizing protein A as a novel member of the staphylococcal surface protein adhesin superfamily and suggesting its potential role in the pathogenesis of endovascular staphylococcal disease.     

Cord blood transplantation in Western Australia

Background/Aims: Thirty‐one umbilical cord blood transplants performed in Western Australia were retrospectively examined in order to document local experience and relevant prognostic factors. Three cord units were from human leucocyte antigen‐matched siblings and the remainder were unrelated single (n= 22) or double (n= 6) cord blood transplants. Methods: Twenty patients were transplanted for malignant conditions and 11 for non‐malignant conditions. Cord units contained a median of 5.6 × 10⁷ total nucleated cells/kg and 1.4 × 10⁵ CD34+ cells/kg. Cumulative incidence of neutrophil engraftment was 76% at day 60. Results: Of those who did not engraft, two patients remain alive following subsequent allogeneic bone marrow transplant. There were no deaths caused by graft‐versus‐host disease. Overall survival at median follow up of 28 months was 62%. Two year overall survival was influenced by type of disease (non‐malignant = 91 ± 9% vs malignant = 41 ± 13%, P= 0.005), total nucleated cell dose (>3.5 × 10⁷/kg = 87 ± 9% vs <3.5 × 10⁷/kg = 34 ± 15%, P= 0.01) and CD34 dose (>1.7 × 10⁵/kg = 92% vs <1.7 × 10⁵/kg = 46%, P= 0.04). Age and human leucocyte antigen match did not influence survival. Four relapses occurred, all of which were fatal. Conclusion: Cord blood transplantation for malignant and non‐malignant disease is practised in Western Australia and outcomes are satisfactory. Trends and techniques in cord blood transplantation in this state are comparable with those observed nationally and overseas. Although numbers are small, cell dose appears to be predictive of overall survival.     

Spectral monitoring of two-spotted spider mite damage to pepper leaves

Two-spotted spider mites (TSSM; Tetranychus urticae Koch) cause significant damage to crops and yields, in the field as well as in greenhouses. By feeding, TSSM destroy chloroplast-containing cells; this damage can be spectrally detected in the reflectance of the visible and near-infrared regions. This study focuses on hyperspectral reflectance data of greenhouse pepper (Capsicum annuum) leaves, obtained by integrated sphere. The reflectance data were transformed into vegetation indices allowing early TSSM damage detection by separation between leaf damage levels. One-way analysis of variance of coupled damage levels was applied to each of the vegetation indices. We concluded that early identification of TSSM greenhouse pepper leaf damage can be obtained by multispectral means. Furthermore, the proposed methods may identify the damage on the upper side of the leaves although the TSSM feed on the underside of leaves.     

Endoscopic Therapy of Early Colorectal Cancer (pT1) - A Prospective Study

INTRODUCTION: In a prospective study initiated in 1982, we have been investigating the question as to whether - and if so, which - pT1 carcinomas of the colorectum can be treated exclusively via the endoscope. METHOD: In the period between February 1, 1982 and April 30, 2001, a total of 5,470 polyps were removed endoscopically at the Medical Department I of the Klinikum Ludwigsburg. Among these lesions, a total of 144 (2.6 %) pT1 carcinomas were found in 141 patients. We were able to follow 120 patients with 123 pT1 carcinomas over a mean follow-up period of 46 months (range: 1-60). In low-risk situations (definitive removal in healthy tissue, G1-G2, no lymphatic involvement), endoscopic treatment alone usually represented sufficient treatment. In high-risk cases (removal in healthy tissue uncertain or negative, and/or lymphatic vessel involvement, and/or G3/G4), subsequent surgical resection was carried out. RESULTS: 64 cases were classified as high-risk, 59 as low-risk. Nevertheless, 9 patients with 10 low-risk carcinomas were submitted to surgery (young age, patient's own request). In none of these 10 cases was residual tumour or lymph node metastasis detected in the surgical specimen. 47 patients with 49 low-risk carcinomas were treated solely by endoscopic polypectomy using the diathermy snare, and 45 patients with 47 carcinomas remained recurrence-free during the follow-up period. In a single case, a local recurrence was detected 2 months after polypectomy and underwent curative resection. In another case, peritoneal carcinosis with tumour infiltrating into the colon developed 8 months after initial treatment; this, however, was most probably a recurrence of a previously operated carcinoma of the uterus. Among the high-risk cases, 10 were not submitted to surgery on account of advanced age and/or rejection of an operation by the patient; all remained recurrence-free. Among the surgically treated high-risk carcinomas, 3 surgical specimens contained residual tumour, while 2 revealed a lymph node metastasis. In our group of patients, no tumour-related mortality was seen among endoscopically treated patients. DISCUSSION: In the light of the fact that the reported mortality rate associated with open surgery for colorectal carcinoma is 3 % as compared with about 1 % risk of lymph node metastasis and 0,1 % mortality rate for the endoscopic modality, endoscopic removal of a pT1 tumour in a low-risk situation followed by appropriate surveillance can be considered as adequate treatment.