CT findings in 14 patients with Mycobacterium chelonae pulmonary infection

OBJECTIVE: The purpose of this report is to describe helical and high-resolution CT findings in 14 patients with pulmonary infection caused by Mycobacterium chelonae, a nontuberculous mycobacterial species that has become increasingly recognized as a rare but significant cause of chronic lung infection in immunocompetent patients. CONCLUSION: Bronchiectasis, nodules, and consolidation are the most common CT features of M. chelonae pulmonary infection. Cavities are less common. These CT findings resemble those reported for Mycobacterium avium complex. In this study, M. chelonae pulmonary infection occurred exclusively in middle-aged and older women.     

Quantitative results

Detailed analysis of information obtained is still under way, but initial trends appear to show stable enrollment, maintenance of minimum service levels, and lower hospital utilization.     

An evaluation of chemical photoreactivity and the relationship to phototoxicity

The existing regulatory guidance for photosafety testing of new drug products states that studies are warranted for those chemicals that both absorb light in the range of 290–700 nm, and that are either applied locally/topically, or “reach” (EMEA)/“significantly partition” (FDA) to the skin or eyes. The initial in vitro study recommended for the assessment of phototoxic potential is the 3T3 Neutral Red Uptake (NRU) Assay. The current study was undertaken to establish superior triggers for the initiation of biological photosafety testing. In this study, photophysical and photochemical parameters for 40 drug or drug-like molecules were studied. Principal Component Analysis (PCA), Partial Least Squares-Discriminant Analysis (PLS-DA), and a fivefold cross-validation PLS algorithm were used to evaluate the relationship between subsets of photophysical and photochemical parameters with the 3T3 NRU PIF/MPE (Photo Irritation Factor/Mean Photo Effect) results. The parameters most indicative of a 3T3 NRU positive PIF or MPE score were the extent of degradation in solution, the quantum yield of formation of singlet oxygen and the relative formation of superoxide anion. The results demonstrate that while absorption of light is critical to the induction of a light-induced process, it is the resultant events that may be used to predict the 3T3 NRU assay result. It is therefore proposed that the trigger for photosafety testing be revised to include a molecular basis for photoreactivity. From this limited investigation, estimated thresholds leading to 3T3 NRU positive results due to photodegradation, formation of singlet oxygen quantum yield or a relative superoxide anion formation value are proposed.     

Expression of HLA class I and II antigens on cells of the human trabecular meshwork

Human corneoscleral tissue containing trabecular meshwork and cultured human trabecular cells were examined for HLA-ABC (class I) and HLA-DR (class II) antigens of the major histocompatibility complex using an indirect immunofluorescence assay. Class I antigens were detected in the trabecular meshwork on frozen sections and on cultured trabecular cells. Class II antigens were constitutively expressed on some, but not all, cells within the trabecular meshwork. Many more cells could be induced to express class II antigens by pre-incubation in human gamma interferon. Cultured trabecular cells did not express class II antigens constitutively, but expression could be induced by gamma interferon. This study suggests that, in addition to Langerhans' cells at the limbus, other cell types within the anterior segment express major histocompatibility complex-encoded class II antigens either constitutively or inducibly. These cells may be important for the initiation and regulation of ocular immunity.