Thrombospondin mediates the cytoadherence of Plasmodium falciparum- infected red cells to vascular endothelium in shear flow conditions

Cerebral malaria is thought to involve specific attachment of Plasmodium falciparum-infected knobby red cells to venular endothelium. The nature of surface ligands on host endothelial cells that may mediate cytoadherence is poorly understood. We have investigated the effects of soluble thrombospondin, rabbit antiserum raised against thrombospondin, and human immune serum on cytoadherence of parasitized erythrocytes in ex vivo mesocecum vasculature. Preincubation of infected red cells with soluble thrombospondin or human immune serum inhibits binding of infected red cells to rat venular endothelium. Infusion of the microcirculatory preparation with rabbit antithrombospondin antibodies before perfusion of parasitized erythrocytes also resulted in decreased cytoadherence. In addition, incubation of infected cells with human immune sera obtained from malaria patients significantly inhibited the observed cytoadherence. Our results indicate that thrombospondin mediates binding of infected red cells to venular endothelium and may thus be involved in the pathogenesis of cerebral malaria.     

Prevention of nevirapine-associated exanthema using slow dose escalation and/or corticosteroids

OBJECTIVE: The appearance of rash is one of the most frequent and limiting side-effects during the first 4 weeks of treatment with nevirapine (NVP). We explored the efficacy and safety of four different strategies for reducing the incidence of this complication. PATIENTS AND METHODS: Four-hundred and sixty-nine patients were assigned randomly to accomplish the induction phase of NVP following either the standard recommendation of 200 mg daily during the first 2 weeks (n = 166), or any of three new strategies: adding prednisone 50 mg each other day during the first 2 weeks (n = 93); using a slowly escalating dose, beginning with 100 mg daily the first week, and increasing the dose by 100 mg/week up to the full daily dose of 400 mg (n = 107); and combining both the addition of prednisone with the slowly escalating dose (n = 103). A pharmacokinetic substudy was performed in seven patients receiving 100 mg of NVP during the first week. RESULTS: The incidence of rash diminished from 18.7% using the standard recommendation to 9.2% using the alternative approaches (P = 0.003). Rash appeared in 11.2%, 8.6%, and 7.7% of subjects assigned to receive the slowly escalating dose, prednisone, or both, respectively, without significant differences among them. The rate of drug discontinuation was also diminished by one-half using the new approaches (8.5% versus 4.3%; P = 0.06). NVP plasma concentrations within the first week of treatment using 100 mg daily were above the 90% inhibitory concentration for wild-type HIV-1 in all instances. CONCLUSION: The incidence of rash complicating the first few weeks of treatment with NVP can be diminished by adding corticosteroids for 2 weeks to the standard recommendation, or by using a slowly escalating dose. This second approach is proven to be pharmacokinetically safe.     

Distal Radial Artery Approach to Prevent Radial Artery Occlusion Trial

ObjectivesThe aim of this study was to compare the rate of proximal radial artery occlusion (RAO) with Doppler ultrasound between distal and conventional radial access 24 h and 30 days after a transradial coronary procedure.BackgroundThe use of distal radial access to prevent proximal RAO (PRAO) in the proximal segment at 24 h and 30 days after a procedure, compared with conventional radial access, is unknown.MethodsThis was a prospective, comparative, longitudinal, randomized study. A total of 282 patients were randomized to either proximal radial access (n = 142) or distal radial access (n = 140) to evaluate the superiority of the distal approach in the prevention of PRAO with Doppler ultrasound 24 h and 30 days after a transradial coronary procedure.ResultsIn the per protocol analysis, the rates of PRAO at 24 h and 30 days were 8.4% and 5.6% in the proximal group and 0.7% and 0.7% in the distal group, respectively (24 h: odds ratio [OR]: 12.8; 95% confidence interval [CI]: 1.6 to 100.0; p = 0.002; 30 days: OR: 8.2; 95% CI: 1.0 to 67.2; p = 0.019). In an intention-to-treat analysis, the 24-h and 30-day rates of PRAO were 8.8% and 6.4% for proximal radial access and 1.2% and 0.6% in the distal radial access group (24 h: OR: 7.4; 95% CI: 1.6 to 34.3; p = 0.003; 30 days: OR: 10.6; 95% CI: 1.3 to 86.4; p = 0.007).ConclusionsDistal radial access prevents RAO in the proximal segment at 24 h and 30 days after the procedure compared with conventional radial access.     

Bladder tissue regeneration using acellular bi-layer silk scaffolds in a large animal model of augmentation cystoplasty

Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a porcine model of augmentation cystoplasty. Two bi-layer matrix configurations were fabricated by solvent-casting/salt leaching either alone (Group 1) or in combination with silk film casting (Group 2) to yield porous foams buttressed by heterogeneous surface pore occlusions or homogenous silk films, respectively. Bladder augmentation was performed with each scaffold group (6 × 6 cm²) in juvenile Yorkshire swine for 3 m of implantation. Augmented animals exhibited high rates of survival (Group 1: 5/6, 83%; Group 2: 4/4, 100%) and voluntary voiding over the course of the study period. Urodynamic evaluations demonstrated mean increases in bladder capacity over pre-operative levels (Group 1: 277%; Group 2: 153%) which exceeded nonsurgical control gains (144%) encountered due to animal growth. Similarly, elevations in bladder compliance were substantially higher in augmented animals from baseline (Group 1: 357%; Group 2: 147%) in comparison to controls (41%). Gross tissue evaluations revealed that both matrix configurations supported extensive de novo tissue formation throughout the entire original implantation site which exhibited ultimate tensile strength similar to nonsurgical counterparts. Histological and immunohistochemical analyses showed that both implant groups promoted comparable extents of smooth muscle regeneration and contractile protein (α-smooth muscle actin and SM22α) expression within defect sites similar to controls. Parallel evaluations demonstrated the formation of a transitional, multi-layered urothelium with prominent cytokeratin, uroplakin, and p63 protein expression in both matrix groups. De novo innervation and vascularization processes were evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Ex vivo organ bath studies demonstrated that regenerated tissues supported by both silk matrices displayed contractile responses to carbachol, α,β-methylene-ATP, KCl, and electrical field stimulation similar to controls. Our data detail the ability of acellular silk scaffolds to support regeneration of innervated, vascularized smooth muscle and urothelial tissues within 3 m with structural, mechanical, and functional properties comparable to native tissue in a porcine model of bladder repair.     

A mechanical microconnector system for restoration of tissue continuity and long-term drug application into the injured spinal cord

Complete transection of the spinal cord leaves a gap of several mm which fills with fibrous scar tissue. Several approaches in rodent models have used tubes, foams, matrices or tissue implants to bridge this gap. Here, we describe a mechanical microconnector system (mMS) to re-adjust the retracted spinal cord stumps. The mMS is a multi-channel system of polymethylmethacrylate (PMMA), designed to fit into the spinal cord tissue gap after transection, with an outlet tubing system to apply negative pressure to the mMS thus sucking the spinal cord stumps into the honeycomb-structured holes. The stumps adhere to the microstructure of the mMS walls and remain in the mMS after removal of the vacuum. We show that the mMS preserves tissue integrity and allows axonal regrowth at 2, 5 and 19 weeks post lesion with no adverse tissue effects like in-bleeding or cyst formation. Preliminary assessment of locomotor function in the open field suggested beneficial effects of the mMS. Additional inner micro-channels enable local substance delivery into the lesion center via an attached osmotic minipump. We suggest that the mMS is a suitable device to adapt and stabilize the injured spinal cord after surgical resection of scar tissue (e.g., for chronic patients) or traumatic injuries with large tissue and bone damages.     

Immunotherapeutic effects of recombinant adenovirus encoding granulocyte–macrophage colony‐stimulating factor in experimental pulmonary tuberculosis

BALB/c mice with pulmonary tuberculosis (TB) develop a T helper cell type 1 that temporarily controls bacterial growth. Bacterial proliferation increases, accompanied by decreasing expression of interferon (IFN)‐γ, tumour necrosis factor (TNF)‐α and inducible nitric oxide synthase (iNOS). Activation of dendritic cells (DCs) is delayed. Intratracheal administration of only one dose of recombinant adenoviruses encoding granulocyte–macrophage colony‐stimulating factor (AdGM‐CSF) 1 day before Mycobacterium tuberculosis (Mtb) infection produced a significant decrease of pulmonary bacterial loads, higher activated DCs and increased expression of TNF‐α, IFN‐γ and iNOS. When AdGM‐CSF was given in female mice B6D2F1 (C57BL/6J X DBA/2J) infected with a low Mtb dose to induce chronic infection similar to latent infection and corticosterone was used to induce reactivation, a very low bacilli burden in lungs was detected, and the same effect was observed in healthy mice co‐housed with mice infected with mild and highly virulent bacteria in a model of transmissibility. Thus, GM‐CSF is a significant cytokine in the immune protection against Mtb and gene therapy with AdGM‐CSF increased protective immunity when administered in a single dose 1 day before Mtb infection in a model of progressive disease, and when used to prevent reactivation of latent infection or transmission.     

Factor V deficiency in Philadelphia-positive chronic myelogenous leukemia

Factor V deficiency has been identified in 8 of 8 patients 7--20 yr of age, with Philadelphia-positive (Ph1+) chronic myelogenous leukemia (CML). In these 8 patients, factor V deficiency was not due to hepatic dysfunction, factor V inhibitors, or disseminated intravascular coagulation. In 3 patients, factor V activity rose 10%--12% (0.10--0.12 U/ml) after the infusion of 28--31 ml/kg body weight of fresh frozen plasma (FFP). The rise persisted less than 14 hr. The mean measured postinfusion rise in factor V was 18% of the expected rise calculated from the volume of FFP infused in the patients' plasma volume. In 4 patients, a small transient rise in factor V activity occurred after splenectomy or plateletpheresis. Factor V deficiency was completely corrected after a marked reduction in bone marrow cellularity in 2 patients with Ph1+ CML treated with extensive chemotherapy, total body irradiation, and bone marrow transplantation. Factor V deficiency was retrospectively observed in 6 of 20 patients, ages 20--80 yr, with Ph1+ CML and 3 of 6 patients with other myeloproliferative disorders. The factor V deficiency appears to be associated with the large myeloid- megakaryocytic cell mass characteristic of CML and other myeloproliferative disorders.     

Genetic Characterization of Goutanap Virus,a Novel Virus Related to Negeviruses,Cileviruses and Higreviruses

Pools of mosquitoes collected in Côte d’Ivoire and Mexico were tested for cytopathic effects on the mosquito cell line C6/36. Seven pools induced strong cytopathic effects after one to five days post infection and were further investigated by deep sequencing. The genomes of six virus isolates from Côte d’Ivoire showed pairwise nucleotide identities of ~99% among each other and of 56%–60% to Dezidougou virus and Wallerfield virus, two insect-specific viruses belonging to the proposed new taxon Negevirus. The novel virus was tentatively named Goutanap virus. The isolate derived from the Mexican mosquitoes showed 95% pairwise identity to Piura virus and was suggested to be a strain of Piura virus, named C6.7-MX-2008. Phylogenetic inferences based on a concatenated alignment of the methyltransferase, helicase, and RNA-dependent RNA polymerase domains showed that the new taxon Negevirus formed two monophyletic clades, named Nelorpivirus and Sandewavirus after the viruses grouping in these clades. Branch lengths separating these clades were equivalent to those of the related genera Cilevirus, Higrevirus and Blunervirus, as well as to those within the family Virgaviridae. Genetic distances and phylogenetic analyses suggest that Nelorpivirus and Sandewavirus might form taxonomic groups on genus level that may define alone or together with Cilevirus, Higrevirus and Blunervirus a viral family.