Investigating women with postmenopausal bleeding: The utility of endometrial thickness in transvaginal ultrasound.

BACKGROUND: Australian clinical guidelines recommend further investigation in females with postmenopausal bleeding (PMB) and endometrial thickness (ET) of ≥4 mm on transvaginal ultrasound (TVUS). However, the literature indicates that an ET of ≥3 mm as an upper limit is a more sensitive predictor of endometrial malignancy (EM) in females with PMB. AIMS: To assess whether Australian guidelines for PMB with an upper limit of 4 mm ET on ultrasound investigation, is sensitive enough for malignancy detection. MATERIAL AND METHODS: A retrospective study was performed on tissue results in PMB presentations to the Gold Coast Hospital and Health Service between 2011 and 2015. RESULTS: Twenty point nine percent of women with PMB had a malignancy. With an upper limit of 4 mm in ET on ultrasound, malignancy was present in 22% of participants. [Correction added on 10 July 2020, after first online publication: percentage of women with PMB that had a malignancy has been amended to twenty point nine percent.] CONCLUSIONS: A limit of 3 mm for ET in PMB, along with office endometrial biopsy, should be considered to ensure timely diagnoses.

Three Wzy polymerases are specific for particular forms of an internal linkage in otherwise identical O units.

The Wzx/Wzy-dependent pathway is the predominant pathway for O-antigen production in Gram-negative bacteria. The O-antigen repeat unit (O unit) is an oligosaccharide that is assembled at the cytoplasmic face of the membrane on undecaprenyl pyrophosphate. Wzx then flips it to the periplasmic face for polymerization by Wzy, which adds an O unit to the reducing end of a growing O-unit polymer in each round of polymerization. Wzx and Wzy both exhibit enormous sequence diversity. It has recently been shown that, contrary to earlier reports, the efficiency of diverse Wzx forms can be significantly reduced by minor structural variations to their native O-unit substrate. However, details of Wzy substrate specificity remain unexplored. The closely related galactose-initiated Salmonella O antigens present a rare opportunity to address these matters. The D1 and D2 O units differ only in an internal mannose-rhamnose linkage, and D3 expresses both in the same chain. D1 and D2 polymerases were shown to be specific for O units with their respective α or ß configuration for the internal mannose-rhamnose linkage. The Wzy encoded by D3 gene cluster polymerizes only D1 O units, and deleting the gene does not eliminate polymeric O antigen, both observations indicating the presence of an additional wzy gene. The levels of Wzx and Wzy substrate specificity will affect the ease with which new O units can evolve, and also our ability to modify O antigens, capsules or secreted polysaccharides by glyco-engineering, to generate novel polysaccharides, as the Wzx/Wzy-dependent pathway is responsible for much of the diversity.