Airborne rhinovirus detection and effect of ultraviolet irradiation on detection by a semi-nested RT-PCR assay

BACKGROUND: Rhinovirus, the most common cause of upper respiratory tract infections, has been implicated in asthma exacerbations and possibly asthma deaths. Although the method of transmission of rhinoviruses is disputed, several studies have demonstrated that aerosol transmission is a likely method of transmission among adults. As a first step in studies of possible airborne rhinovirus transmission, we developed methods to detect aerosolized rhinovirus by extending existing technology for detecting infectious agents in nasal specimens. METHODS: We aerosolized rhinovirus in a small aerosol chamber. Experiments were conducted with decreasing concentrations of rhinovirus. To determine the effect of UV irradiation on detection of rhinoviral aerosols, we also conducted experiments in which we exposed aerosols to a UV dose of 684 mJ/m(2). Aerosols were collected on Teflon filters and rhinovirus recovered in Qiagen AVL buffer using the Qiagen QIAamp Viral RNA Kit (Qiagen Corp., Valencia, California) followed by semi-nested RT-PCR and detection by gel electrophoresis. RESULTS: We obtained positive results from filter samples that had collected at least 1.3 TCID(50 )of aerosolized rhinovirus. Ultraviolet irradiation of airborne virus at doses much greater than those used in upper-room UV germicidal irradiation applications did not inhibit subsequent detection with the RT-PCR assay. CONCLUSION: The air sampling and extraction methodology developed in this study should be applicable to the detection of rhinovirus and other airborne viruses in the indoor air of offices and schools. This method, however, cannot distinguish UV inactivated virus from infectious viral particles

Physiology and Pathophysiology of Wound Healing in Diabetes

Wound healing is a dynamic process comprising of overlapping phases of hemostasis, inflammation, proliferation, and remodeling that involve multiple cell types. This highly organized and coordinated series of processes result in the restoration of tissue integrity. Deregulation in any of these processes leads to a delayed or nonhealing phenotype as seen in diabetic foot ulcers (DFUs). The functions and cell-to-cell communication between different cell types contributing to wound healing (keratinocytes, fibroblasts, endothelial cells, neutrophils, and macrophages) and their deregulation in chronic nonhealing ulcers are discussed in detail. The balance of signaling factors, including growth factors and gene expression regulators such as microRNA, and their spatiotemporal control is indispensable for successful wound healing, while their dysregulation contributes to pathophysiology of DFUs. Additional factors that contribute to the delayed healing seen in diabetes include macro- and microvascular, neuropathic, immune functions, and microbiome abnormalities. Novel therapeutic approaches including cell therapy, stem cells, and micrografting that provide perspective on how to efficiently treat patients with DFUs are also discussed