Legionella pneumophila is an intracellular bacterial parasite of freshwater protozoa and an accidental waterborne human pathogen. L. pneumophila is highly pleomorphic showing several forms that differentiate within its developmental cycle. In water, L. pneumophila produces viable but non-culturable cells (VBNCCs), which remain largely uncharacterized. We produced VBNCCs from two developmental forms of L. pneumophila [stationary phase forms (SPFs) and mature infectious forms (MIFs)] in two water microcosms [double-deionized (dd) and tap water] at 45°C. In contrast with SPFs, MIFs upheld a robust ultrastructure and high viability in the two water microcosms. In dd-water, MIFs and SPFs lost their culturability faster than in tap water and did not consume their poly-β-hydroxybutyrate inclusions. Resuscitation in Acanthamoeba castellani was only possible for VBNCCs produced from SPFs in tap water. Addition of salts to dd-water prolonged L. pneumophila culturability to tap water levels, suggesting that L. pneumophila requires ions to maintain its readiness to resume growth. VBNCCs resisted detergent lysis and digestion in the ciliate Tetrahymena, except for VBNCCs produced from SPFs in dd-water. L. pneumophila VBNCCs thus show distinct traits according to its originating developmental form and the surrounding water microcosm.
Objective Pathologic tumor size assessment highly depends on the gross specimen size once microscopic cancer size exceeds its macroscopic size, in particular if the dimension along the plane of sectioning is the greatest. We hypothesize that the method by which the specimen size is estimated can yield significantly different tumor size measurements and thus affect breast cancer staging and treatment. Methods The size in the plane of sectioning of 50 lumpectomies over 4 cm was examined by 5 methods: measured grossly in the fresh state and postfixation, and calculated from the gross measurements by 3 different methods. For 15 mastectomies, we measured and calculated the span of the middle 4 and 6 slices using 3 methods. Results For all 50 lumpectomies, fresh measurement yielded the largest size. The difference in size of lumpectomies was greater with increasing specimen size ( P < .001). Using the method of adding 0.4 cm per each submitted sequential section yielded the smallest size in most cases. In mastectomies the span of the middle 4 and 6 slices was significantly larger if calculated from the average slice thickness based on the specimen size. Conclusion The method of specimen size measurement has implications in estimation of tumor size and patient management. It is essential that pathologists be aware of the technique used and its limitations. For individual slice thickness, we highly recommend using the measurements obtained at the time of grossing rather than calculating the average slice thickness from the specimen size.
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