Patients with sickle cell disease (SCD) suffer from intravascular hemolysis associated with vascular injury and dysfunction in mouse models, and painful vaso-occlusive crisis (VOC) involving increased attachment of sickle erythrocytes and activated leukocytes to damaged vascular endothelium. Patrolling monocytes, which normally scavenge damaged cells and debris from the vasculature, express higher levels of anti-inflammatory heme oxygenase 1 (HO-1), a heme degrading enzyme. Here, we show that HO-1-expressing patrolling monocytes protect SCD vasculature from ongoing hemolytic insult and vaso-occlusion. We found that a mean 37% of patrolling monocytes from SCD patients express very high levels of HO-1 (HO-1) vs 6% in healthy controls and demonstrated that HO-1 expression was dependent on uptake of heme-exposed endothelium. SCD patients with a recent VOC episode had lower numbers of HO-1 patrolling monocytes. Heme-mediated vaso-occlusion by mouse SCD red blood cells was exacerbated in mice lacking patrolling monocytes, and reversed following transfer of patrolling monocytes. Altogether, these data indicate that SCD patrolling monocytes remove hemolysis-damaged endothelial cells, resulting in HO-1 upregulation and dampening of VOC, and that perturbation in patrolling monocyte numbers resulting in lower numbers of HO-1 patrolling monocyte may predispose SCD patients to VOC. These data suggest that HO-1 patrolling monocytes are key players in VOC pathophysiology and have potential as therapeutic targets for VOC.
Abscesses in the head and neck frequently have odontogenic sources. As bacterial pathogens and antibiotic resistance patterns may change over time and based on location, we describe the current common bacteria found in odontogenic abscesses, the prevalence of antibiotic resistance, and differences in each between pediatric and adult patients in Upstate New York. This is a retrospective review of patients who underwent drainage of odontogenic abscesses (n = 131) from 2002 to 2012 at an academic institution. The medical records were reviewed for results of abscess cultures, comorbidities, and drainage procedures. Polymicrobial sources were identified in 60.3% and monomicrobial in 33.6%. Overall, the most common bacteria were alpha hemolytic Streptococci (33.6%), Streptococcus milleri (32.1%), Prevotella (16.8%), and coagulase-negative Staphylococcus (14.5%). Candida and Morganella spp were more common in children than in adults. Overall, antibiotic resistance was observed in seven different pathogens. The most common antibiotic resistances were to clindamycin and erythromycin, which should be considered when deciding initial antibiotic therapy, especially in adult patients, who trended in this study toward having pathogens with higher rates of resistance.
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