Lykkegaardtennant9022

The importance of thyroid hormones in the regulation of development, growth, and energy metabolism is well known. Over the last decades, mass spectrometry has been extensively used to investigate thyroid hormone metabolism and to discover and characterize new molecules involved in thyroid hormones production, such as thyrotropin-releasing hormone. In the earlier period, the quantification methods, usually based on gas chromatography-mass spectrometry, were complicated and time consuming. They were mainly focused on basic research, and were not suitable for clinical diagnostics on a routine basis. The development of the modern mass spectrometers, mainly coupled to liquid chromatography, enabled simpler sample preparation procedures, and the accurate quantification of thyroid hormones, of their precursors, and of their metabolites in biological fluids, tissues, and cells became feasible. Nowadays, molecules of physiological and pathological interest can be assayed also for diagnostic purposes on a routine basis, and mass spectrometry is slowly entering the clinical laboratory. This review takes stock of the advancements in the field of thyroid metabolism that were carried out with mass spectrometry, with special focus on the use of this technique for the quantification of molecules involved in thyroid diseases.Microbes live in dense and diverse communities where they deploy many traits that promote the growth and survival of neighbouring species, all the while also competing for shared resources. Because microbial communities are highly dynamic, the costs and benefits of species interactions change over the growth cycle of a community. How mutualistic interactions evolve under such demographic and ecological conditions is still poorly understood. Here, we develop an eco-evolutionary model to explore how different forms of helping with distinct fitness effects (rate-enhancing and yield-enhancing) affect the multiple phases of community growth, and its consequences for the evolution of mutualisms. We specifically focus on a form of yield-enhancing trait in which cooperation augments the common pool of resources, termed niche expansion. We show that although mutualisms in which cooperation increases partners growth rate are generally favoured at early stages of community growth, niche expansion can evolve at later stages where densities are high. Further, we find that niche expansion can promote the evolution of reproductive restraint, in which a focal species adaptively reduces its own growth rate to increase the density of partner species. Our findings suggest that yield-enhancing mutualisms are more prevalent in stable habitats with a constant supply of resources, and where populations typically live at high densities. In general, our findings highlight the need to integrate different components of population growth in the analysis of mutualisms to understand the composition and function of microbial communities.

Flavones are significant indicators of quality in traditional Chinese medicines (TCMs) and thus play a significant role in the quality control of TCMs in the pharmaceutical industry. Most flavones in Dendrobium nobile Lindl, a TCM with a long cultivation history and rich sources, have not been identified. This study was aimed at identifying the flavones in D. nobile from various habitats.

High-performance liquid chromatography (HPLC) coupled with diode-array detection and HPLC multiple-stage tandem mass spectrometry was used to identify the chemical constituents of D. nobile from various habitats, and a method was established to determine the content of vicenin II, violanthin and isoviolanthin. Hierarchical cluster analysis, principal component analysis and orthogonal partial least-squares discriminant analysis were used to analyze the variations among 26 batches from different habitats.

A total of 33 flavones were tentatively identified. Bisindolylmaleimide I cell line Twenty-five flavones, previously undescribed in D. nobile, were acylated by p-coumaroyl, feruloyl, sinapoyl or 3-hydroxy-3-methylglutaryl. The D. nobile habitats were distinguished by significant differences in their flavone content. The C-glycosyl flavones were demonstrated to be characteristic compounds for evaluating D. nobile from various habitats. In particular, flavones acylated with 3-hydroxy-3-methylglutaryl were specific compounds that were only detected in samples from Yunnan.

The results of this study could be used to improve the quality control of D. nobile and could provide references for the identification of acylated C-glycosyl flavones in other natural products.

The results of this study could be used to improve the quality control of D. nobile and could provide references for the identification of acylated C-glycosyl flavones in other natural products.

Abdominoperineal excision (APE) is the operation chosen when a patient has low rectal cancer unamenable to sphincter preserving surgery. Perineal flap reconstruction is associated with less wound morbidity but little is known about oncological outcomes. The objective was to compare outcomes in patients undergoing APE before and after the introduction of a program that utilized flap reconstruction of the perineum.

A retrospective review of a prospectively maintained database was performed. Patients who underwent APE followed by primary closure or flap reconstruction between 1998 and 2018 were selected. The cohorts were divided according to the implementation of the flap reconstruction program in July 2009. Clinicopathological data, recurrence and survival were compared between the cohorts.

One hundred and forty nine patients underwent APE for rectal adenocarcinoma between 1998 and 2018. There were 57 patients in the pre-flap era and 92 in the post-flap era. Forty-six patients underwent flap reconstruction in the latter cohort (50%). More patients in the post-flap era underwent neoadjuvant chemoradiotherapy (85.9% vs. 63.2%; p < .01). Margin positivity rates decreased from 21.1% in the pre-flap era to 10.9% in the post-flap era (p = .10) and there was an associated improvement in incidence and time to local recurrence (p = .03).

The use of perineal flap reconstruction is associated with a longer median time to local recurrence. Perineal flap reconstruction may contribute to reduced margin positivity.

The use of perineal flap reconstruction is associated with a longer median time to local recurrence. Perineal flap reconstruction may contribute to reduced margin positivity.