The role of AtMSH2 in homologous recombination in Arabidopsis thaliana

During homologous recombination (HR), a heteroduplex DNA is formed as a consequence of strand invasion. When the two homologous strands differ in sequence, a mismatch is generated. Earlier studies showed that mismatched heteroduplex often triggers abortion of recombination and that a pivotal component of this pathway is the mismatch repair Msh2 protein. In this study, we analysed the roles of AtMSH2 in suppression of recombination in Arabidopsis. We report that AtMSH2 has a broad range of anti-recombination effects: it suppresses recombination between divergent direct repeats in somatic cells or between homologues from different ecotypes during meiosis. This is the first example of a plant gene that affects HR as a function of sequence divergence and that has an anti-recombination meiotic effect. We discuss the implications of these results for plant improvement by gene transfer across species.     

Anti-inflammatory and immunosuppressive drugs and reproduction

Rheumatic diseases in women of childbearing years may necessitate drug treatment during a pregnancy, to control maternal disease activity and to ensure a successful pregnancy outcome. This survey is based on a consensus workshop of international experts discussing effects of anti-inflammatory, immunosuppressive and biological drugs during pregnancy and lactation. In addition, effects of these drugs on male and female fertility and possible long-term effects on infants exposed to drugs antenatally are discussed where data were available. Recommendations for drug treatment during pregnancy and lactation are given.     

Surface heparinization of polyurethane via bromoalkylation of hard segment nitrogens

Previous research from our group has demonstrated that bromoalkylation of polyurethane elastomers via base mediated activation of the urethane-hard segment nitrogen groups can be used to either attach bisphosphonate groups to confer calcification resistance or append cholesterol to promote endothelial cell adhesion. In the present studies we further explore the potential of this chemical approach by investigating bulk carboxylation of polyurethanes via bromoalkylation to enable surface heparinization for thromboresistance. Thus, polyurethane (PU) was modified with pendant 7-carboxy-5-thiaheptyl groups using a polymer-analogous reaction of bromobutylated PU with tetrabutylammonium 3-mercaptopropionate in mild conditions. The grafting of polyallylamine (PAA) onto the surface of carboxylated PU via direct coupling of amino and carboxy groups resulted in high levels of PAA (up to 8 mug/cm(2)). The surface-aminated PU was further covalently modified with unfractionated heparin as confirmed by FTIR. Fluorescence labeling of PAA hydrochloride and heparin with BODIPY-FL was used to quantify the extent of surface modifications. Heparin was covalently bound at a high level (1.11 +/- 0.06 mug/cm(2)) and was shown to be active, with demonstrable Factor Xa inhibition and platelet factor IV binding. It is concluded that surface amination of bulk-carboxylated PU represents a novel approach for heparinizing PU; carboxylation followed by surface amination represents another important dimension of bromo-alkyl activation of polyurethane hard segments, thereby enabling heparinization.     

Outcome of cats adopted from a biomedical research program

Adoption of companion animals retired from biomedical research projects can provide an alternative, humane method for their disposition. For more than a decade, the University of Florida College of Veterinary Medicine has allowed investigators to arrange for the adoption of nonhuman animals used in their research. This report directed a survey to caregivers (owners) of 458 cats adopted over a 6-year period. The survey determined (a) retention rate of adopted cats in their original homes, (b) characteristics of adopters and cats, (c) adopters' initial expectations and subsequent experiences with the cats, (d) quality of the human-animal bond, and (e) adopters' perceptions of the adoption process. Completed surveys totaled 275 (60.0% response rate) with a median follow-up interval of 38 months. Of cats surveyed, 91.3% were still in their original homes, 91.0% had seen a veterinarian following adoption, and 80.4% were highly valued family members. The procedures followed to place cats in appropriate homes satisfied the vast majority of adopters surveyed. These results suggest that adoption into private homes is a viable alternative for cats who have completed research studies.     

Immobilization of gene vectors on polyurethane surfaces using a monoclonal antibody for localized gene delivery

BACKGROUND: Conventional strategies of gene therapy using viral vectors result in suboptimal localization and potentially dangerous distal spread of vector. We hypothesized that localized delivery of adenoviral gene vectors could be achieved from a polyurethane (PU) film through a mechanism involving anti-viral antibody tethering. METHODS: PU films were formulated with a collagen coating. Anti-adenoviral monoclonal antibodies were covalently bound to the collagen surface. These antibodies enabled tethering of replication-defective adenoviruses [Ad-GFP (encoding green fluorescent protein)] through highly specific antigen-antibody affinity. The binding stability and in vitro delivery of virus bound on PU films were investigated. Cell culture studies with rat arterial smooth muscle cells (A10) assessed transduction on or near the PU matrix. In vivo experiments with collagen-coated PU films investigated atrial epicardial implant and subdermal implant models in Yorkshire swine. RESULTS: We report for the first time successful PU film-based gene delivery using antibody-tethered adenovirus encoding the green fluorescent protein (GFP), demonstrating efficient and highly localized gene delivery to arterial smooth muscle cells in cell culture and pig implant. In comparison, direct injections of viral vectors into subcutaneous sites gave sparse, needle-track-oriented GFP expression patterns. CONCLUSION: We conclude that PU film is a suitable platform for a localizable viral vector delivery system that also prevents systemic spread of vector. Gene delivery using PU film-based anti-viral antibody tethering of vectors should be suitable for a wide array of single or multiple therapeutic gene strategies, and for further device-based gene delivery therapeutic strategies.     

Impaired neutrophil functions in the pathogenesis of an outbreak of recurrent furunculosis caused by methicillin-resistant Staphylococcus aureus among mentally retarded adults

Staphylococcus aureus is an important cause of skin infections. We recently described an outbreak of recurrent furunculosis involving methicillin-resistant S. aureus among mentally retarded adults. We sought to determine the role of impaired neutrophil functions in its pathogenesis. Blood neutrophil functions were determined during both the outbreak (1997) and a disease-free period (2000). Chemotaxis was measured by migration toward formyl-methionyl-leucyl-phenylalanine (FMLP), specifically and randomly; phagocytosis of opsonized zymosan (OZ) was assessed by microscopy; superoxide production was determined by cytochrome c reduction in unstimulated neutrophils and after stimulation with 50 ng/ml phorbol myristate acetate, 1 mg/ml OZ or 5 x 10(-7)M FMLP. Functions were compared between recurrent furunculosis (n=10) and non-recurrent furunculosis patients (n=13). During 2000, functions were normal among the 23 subjects, except for specific/nonspecific chemotaxis (mean 68%+/-26 and 69%+/-28). During infection, recurrent furunculosis patients had a significantly increased basal superoxide production as compared to disease-free period (10.5+/-4.7 vs. 4.9+/-1.9 nmol O(-)(2)/10(6) cells/min, p=0.003). During the disease-free period, recurrent furunculosis patients had lower basal superoxide production (4.9+/-1.9 vs. 7.7+/-3.5, p=0.067) and impaired specific chemotaxis (57%+/-28 vs. 76%+/-21, p<0.05) as compared to non-recurrent furunculosis patients. Only specific chemotaxis was an independent risk factor for recurrent furunculosis. Mentally retarded adults have impaired chemotaxis, with recurrent furunculosis cases having an even greater impairment. Abnormal specific chemotaxis is an independent risk factor for recurrent furunculosis. Impaired neutrophil functions thus have a role in the pathogenesis of outbreaks of recurrent furunculosis.