Induction of endothelial cell proliferation by recombinant and microparticle-tissue factor involves β1-integrin and extracellular signal regulated kinase activation

Objective: Increased levels of circulating tissue factor (TF) in the form of microparticles increase the risk of thrombosis. However, any direct influence of microparticle-associated TF on vascular endothelial cell proliferation is not known. In this study, the influence of recombinant and microparticle- associated TF on endothelial cell proliferation and mitogen-activated protein kinase signaling mechanisms was examined. Methods and Results: Incubation of human coronary artery endothelial cells with lipidated recombinant full-length TF, or TF-containing microparticles (50 to 200 pmol/L TF), increased the rate of cell proliferation and induced phosphorylation of extracellular signal regulated kinase 1 in a TF-dependent manner. Inhibition of extracellular signal regulated kinase 1/2 using PD98059 or extracellular signal regulated kinase 1/2 antisense oligonucleotides or inhibition of c-Jun N-terminal kinase reduced recombinant TF-mediated cell proliferation. PD98059 also reduced cell proliferation in response to TF-containing microparticles. Inclusion of FVIIa (5 nmol/L) and FXa (10 nmol/L) or preincubation of cells with an inhibitory anti-FVIIa antibody had no additional influence on TF-mediated cell proliferation. However, preincubation of exogenous TF with a β1-integrin peptide (amino acids 579 to 799) reduced TF-mediated proliferation. Conclusion: High concentrations of recombinant or microparticle-associated TF stimulate endothelial cell proliferation through activation of the extracellular signal regulated kinase 1/2 pathway, mediated through a novel mechanism requiring the interaction of exogenous TF with cell surface β1-integrin and independent of FVIIa. © 2010 American Heart Association, Inc

Filamin-A is required for the incorporation of tissue factor into cell-derived microvesicles

We previously reported that the incorporation of tissue factor (TF) into cell-derived microvesicles (MVs) is regulated by the phosphorylation of the cytoplasmic domain of TF. Since the cytoskeletal protein filamin-A is known to bind to the cytoplasmic domain of TF in a phosphorylation-dependent manner, the involvement of filamin-A in the incorporation of TF into MVs was examined. Endothelial cells were transfected to express TF, whereas MDA-MB-231 cells were used to examine endogenously expressed TF. MV release was induced by activating protease-activated receptor-2 (PAR2). Partial suppression of filamin-A expression using two different filamin-A siRNA sequences resulted in significant reductions in the incorporation of TF antigen into MVs as determined by TF-ELISA and western blot analysis, and was reflected in reduced thrombin-generation and FXa-generation capacities of these MVs. Deletion of the cytoplasmic domain of TF also resulted in reduced incorporation of TF into MVs, whereas the suppression of filamin-A expression had no additional effect on the incorporation of truncated TF into MVs. Partial suppression of filamin-A expression had no effect on the number and size distribution of the released MVs. However, >90 % suppression of filamin-A expression resulted in increased MV release, possibly as a result of increased instability of the plasma membrane and underlying cytoskeleton. In conclusion, the presence of filamin-A appears to be essential for the incorporation of TF into MVs following PAR2 activation, but is not required for the process of MV formation and release following PAR2 activation

Tuning terahertz transitions in a double-gated quantum ring

We theoretically investigate the optical functionality of a semiconducting quantum ring manipulated by two electrostatic lateral gates used to induce a double quantum well along the ring. The well parameters and corresponding inter-level spacings, which lie in the THz range, are highly sensitive to the gate voltages. Our analysis shows that selection rules for inter-level dipole transitions, caused by linearly polarized excitations, depend on the polarization angle with respect to the gates. In striking difference from the conventional symmetric double well potential, the ring geometry permits polarization-dependent transitions between the ground and second excited states, allowing the use of this structure in a three-level lasing scheme.Comment: 7 pages, 6 figure

Influence of human pressures on large river structure and function

A large river study was conducted as part of the Cross Departmental Research Pool (CDRP) ecological integrity project to (i) provide an overview of the macroinvertebrate faunas of large rivers, including those in deep-water habitats, and (ii) to elucidate links between these faunas, river function and anthropogenic stressors. Eleven sites on 6th-order or 7th-order rivers were sampled; four in the South Island and seven in the North Island. We measured (i) macroinvertebrate communities colonising wood, riffles (where present), littoral habitats (1.5 m deep) (ii) ecosystem metabolism using a single-station open-channel approach based on natural changes in dissolved oxygen concentration over a 24-hour period, and (iii) wood and cellulose breakdown. Relationships were investigated between these response variables and reach-scale assessments of habitat quality, underlying upstream and segment environmental variables provided in the Freshwater Environments of New Zealand (FWENZ) database, and anthropogenic pressure variables provided by the Waters of National Importance (WONI) database

Scedosporium prolificans Septic Arthritis

Scedosporium prolificans is an emerging fungal pathogen that can cause significant morbidity, and even mortality, in both immunocompromised and immunocompetent patients. Approximately 10% of patients affected by this rare fungal pathogen present with septic osteomyelitis or arthritis. Overall, the rate of mortality is close to 50%, and several patients with orthopedic infections have required amputations.1 Our patient is a 59-year-old woman, with a history of rheumatoid arthritis requiring immunosuppressants, who presented with a 5-month history of right wrist pain and swelling. She described an oscillating course of swelling, erythema, and pain involving the dorsal aspect of her wrist that did not show sustained response to antibiotics or a radiocarpal joint steroid injection given by other providers. On initial examination, she was afebrile with dorsal wrist swelling. There was no erythema, but wrist mobility was limited. She had tenderness throughout the wrist, but no fluctuance or drainage. All initial laboratory work was normal. Right wrist X-ray showed severe osteopenia with some mild evidence of cortical erosion. Despite the normal laboratory values, her presenting findings of swelling, radiographic erosions, and immunocompromised state prompted concern for atypical septic arthritis. The patient subsequently underwent wrist exploration for tissue and culture harvest. In addition to extensive wrist synovectomy, the proximal pole of the scaphoid, lunate, triquetrum, capitate, hamate, and metacarpal bases all showed evidence of necrosis that required debridement. One week later, her fluid aspirate and bone cultures unexpectedly grew an unidentified fungal species, and she was taken back to the operating room for further debridement and placement of a voriconazole-impregnated cement spacer. The culture grew pan-resistant Scedosporium prolificans, and based on recommendations from Rheumatology and Infectious Disease, the patient was started on a 6-week course of intravenous micafungin, and immunosuppressive medications were stopped. She returned to the operating room for debridement and serial treatments with polyhexamethylene biguanide (PHMB) irrigation until intraoperative tissue cultures showed no growth. PHMB is an antiseptic medication that has been described as a local adjunct to the treatment of resistant fungal infections.2–4 After successful eradication of her infection, she underwent wrist reconstruction and fusion with a double-barrel free fibula osteocutaneous flap. She is now 18 months out from her reconstruction, has healed uneventfully, and has a functional, painless upper extremity

Accumulation of tissue factor in endothelial cells induces cell apoptosis, mediated through p38 and p53 activation

We previously reported that high levels of tissue factor (TF) can induce cellular apoptosis in endothelial. In this study, TF-mediated mechanisms of induction of apoptosis were explored. Endothelial cells were transfected to express wild-type TF. Additionally, cells were transfected to express Asp253-substituted, or Ala253-substitued TF to enhance or prevent TF release respectively. Alternatively, cells were pre-incubated with TF-rich and TF-poor microvesicles. Cell proliferation, apoptosis and the expression of cyclin D1, p53, bax and p21 were measured following activation of cells with PAR2-agonist peptide. Greatest levels of cell proliferation and cyclin D1 expression were observed in cells expressing wild-type or Asp253-substituted TF. In contrast, increased cellular apoptosis was observed in cells expressing Ala253-substituted TF, or cells pre-incubated with TF-rich microvesicles. The level of p53 protein, p53-phosphorylation at ser33, p53 nuclear localisation and transcriptional activity, but not p53 mRNA, were increased in cells expressing wild-type and Ala253-substituted TF, or in cells pre-incubated with TF-rich microvesicles. However, the expression of bax and p21 mRNA, and Bax protein were only increased in cells pre-incubated with TF-rich microvesicle and in cells expressing Ala253-substituted TF. Inhibition of the transcriptional activity of p53 using pifithrin-α suppressed the expression of Bax. Finally, siRNA–mediated suppression of p38α, or inhibition using SB202190 significantly reduced the p53 protein levels, p53 nuclear localisation and transcriptional activity, suppressed Bax expression and prevented cellular apoptosis. In conclusion, accumulation of TF within endothelial cell, or sequestered from the surrounding can induce cellular apoptosis through mechanisms mediated by p38, and involves the stabilisation of p53

Bistable molecular conductors with a field-switchable dipole group

A class of bistable "stator-rotor" molecules is proposed, where a stationary bridge (stator) connects the two electrodes and facilitates electron transport between them. The rotor part, which has a large dipole moment, is attached to an atom of the stator via a single sigma bond. Hydrogen bonds formed between the rotor and stator make the symmetric orientation of the dipole unstable. The rotor has two potential minima with equal energy for rotation about the sigma bond. The dipole orientation, which determines the conduction state of the molecule, can be switched by an external electric field that changes the relative energy of the two potential minima. Both orientation of the rotor correspond to asymmetric current-voltage characteristics that are the reverse of each other, so they are distinguishable electrically. Such bistable stator-rotor molecules could potentially be used as parts of molecular electronic devices.Comment: 8 pages, 7 figure

Distant Light: Songs on Texts by Richard Boada

Distant Light: Songs on Texts by Richard Boada is a collection of songs for baritone voice, piano, alto saxophone, and percussion (vibraphone and marimba). The texts do not present a continuous narrative, but they share common themes. Most are set in the rural South and deal with the conflict between nature and industrial development. This piece functions as a cohesive whole, but each song could be performed separately and would be effective out of the context of the entire work. Distant Light is made up of eight songs and is approximately 23 minutes in duration

A study of the 'industrial factor' in the rheumatic diseases : with special reference to chronic arthritis

All of the evidence, clinical and statistical, that have been collected and analysed in this paper tended to show that there were certain industrial or occupational factors in the aetiology of the Chronic Arthritic Diseases and that those same factors were possibly of importance also in the aetiology of the Fibrositic Diseases.At the same time, the evidence strongly suggested that 'industrial rheumatism' - in the sense of the Rheumatic Diseases from which the industrial workers suffer - was determined more by Social (and perhaps by personal) factors than by strictly occupational factors.If these conclusions were sound, the practical outcome of this study would be that Industry ought not to be expected or asked to shoulder The financial burden- of the whole of Industrial Rheumatism. It should be held responsible only for that part of the whole mass of the Rheumatic Diseases in which a clear and significant industrial factor can be shown to be at work.From the scientific and medical points of view, the most important conclusions to be drawn concerns the unanimity with which the clinical evidence, the sickness records and the Chronic Arthritis Mortality records point to 'exposure to damp' as the most important, strictly occupational, factor in the aetiology of Chronic Arthritis, and perhaps in the aetiology of the Fibrositic Rheunatisms