Succession and fluctuation in the vegetation of a Dutch beach plain

The development of the vegetation of a brackish sand flat with scattered embryo-dunes on one of the West Frisian islands, Schiermonnikoog (The Netherlands), was recorded over a ten-year period. Some persisting trends, as well as pronounced annual fluctuations, were observed. Therophyte populations are especially vulnerable to environmental fluctuation. The behaviour of various species populations is discussed in relation to environmental instability and life-forms. Special attention is paid to the shuttling of populations of short-lived species on the dune slope. The zonation of the latter may vary, which could be ascribed to their reaction on abiotic conditions as affected by specific life-history characteristics, viz. the germination period, the duration of the life-cycle and the mode of reproduction. Some concluding remarks are made about succession and the role species of different life-forms play in this process.     

Triloborhynchus psilastericola n. sp., a parasitic turbellarian (Fam. Pterastericolidae) from the starfish Psilaster andromeda (Müller and Troschel)

The turbellarian Triloborhynchus psilastericola n.sp. (family Pterastericolidae) occurs in the starfish Psilaster andromeda. On approaching maturation it moves from the host's coelom into the glandular pockets of the pyloric caeca with simultaneous loss of almost the entire ciliation. Mature turbellarians feed on the tissue of the pyloric caeca.     

Avian scale development. VI. Ultrastructure of the keratinizing cells of reticulate scales

Reticulate scales develop as radial symmetrical anlagen, in contrast to scuttate scales which appear initially as “epidermal placodes.” Unlike scuttate scales whose outer and inner epidermal surfaces elaborate β-and α-type keratins, respectively, reticulate scales elaborate only one type of epidermal surface which has been reported to give an α-type, X-ray diffraction pattern. We find that, histologically and ultrastructurally, this surface differs from either epidermal surface of scuttate scales. The keratinizing cells become filled with long interweaving bundles of α-filaments which aggregate into rather homogeneous α-fibrils. Keratohyalin granules, which have been shown to be associated with other keratinizing regions in the bird, do not form during the keratinization of reticulate scale epidermis.     

Chemoreception of host volatiles in the bark beetleIps typographus

Summary In the bark beetleIps typographus the stimulating effects of host odour constituents were studied by linking a gas Chromatograph (GC) with electrophysiological recordings from single olfactory receptor cells. Cells were exposed to the complete aroma of natural bark, extracts from host and non-host trees and fractions of these stimuli separated via a GC column. Four minor fractions belonging to two extracts were found to excite olfactory receptor cells. Responsive cells were divided into two main groups reacting exclusively to one fraction and suggesting that the cells were highly specialized to a particular host odour constituent. However, an effective extract or fraction could not be found for half of the olfactory units responding to natural bark, indicating that the relevant stimulatory compounds were lost during the extraction and/or GC procedure.Abbreviations EAG electroantennogram - GC gas-chromatograph     

Bariatric surgery for patients with type 2 diabetes mellitus requiring insulin: Clinical outcome and cost-effectiveness analyses

BackgroundAlthough bariatric surgery is well established as an effective treatment for patients with obesity and type 2 diabetes mellitus (T2DM), there exists reluctance to increase its availability for patients with severe T2DM. The aims of this study were to examine the impact of bariatric surgery on T2DM resolution in patients with obesity and T2DM requiring insulin (T2DM-Ins) using data from a national database and to develop a health economic model to evaluate the cost-effectiveness of surgery in this cohort when compared to best medical treatment (BMT).Methods and findingsClinical data from the National Bariatric Surgical Registry (NBSR), a comprehensive database of bariatric surgery in the United Kingdom, were extracted to analyse outcomes of patients with obesity and T2DM-Ins who underwent primary bariatric surgery between 2009 and 2017. Outcomes for this group were combined with data sourced from a comprehensive literature review in order to develop a state-transition microsimulation model to evaluate cost-effectiveness of bariatric surgery versus BMT for patients over a 5-year time horizon. The main outcome measure for the clinical study was insulin cessation at 1-year post-surgery: relative risks (RR) summarising predictive factors were determined, unadjusted, and after adjusting for variables including age, initial body mass index (BMI), duration of T2DM, and weight loss. Main outcome measures for the economic evaluation were total costs, total quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) at willingness-to-pay threshold of GBP£20,000.A total of 2,484 patients were eligible for inclusion, of which 1,847 had 1-year follow-up data (mean age of 51 years, mean initial BMI 47.2 kg/m², and 64% female). 67% of patients no longer required insulin at 1-year postoperatively: these rates persisted for 4 years. Roux-en-Y gastric bypass (RYGB) was associated with a higher rate of insulin cessation (71.7%) than sleeve gastrectomy (SG; 64.5%; RR 0.92, confidence interval (CI) 0.86–0.99) and adjustable gastric band (AGB; 33.6%; RR 0.45, CI 0.34–0.60; p < 0.001). When adjusted for percentage total weight loss and demographic variables, insulin cessation following surgery was comparable for RYGB and SG (RR 0.97, CI 0.90–1.04), with AGB having the lowest cessation rates (RR 0.55, CI 0.40–0.74; p < 0.001). Over 5 years, bariatric surgery was cost saving compared to BMT (total cost GBP£22,057 versus GBP£26,286 respectively, incremental difference GBP£4,229). This was due to lower treatment costs as well as reduced diabetes-related complications costs and increased health benefits. Limitations of this study include loss to follow-up of patients within the NBSR dataset and that the time horizon for the economic analysis is limited to 5 years. In addition, the study reflects current medical and surgical treatment regimens for this cohort of patients, which may change.ConclusionsIn this study, we observed that in patients with obesity and T2DM-Ins, bariatric surgery was associated with high rates of postoperative cessation of insulin therapy, which is, in turn, a major driver of overall reductions in direct healthcare cost. Our findings suggest that a strategy utilising bariatric surgery for patients with obesity and T2DM-Ins is cost saving to the national healthcare provider (National Health Service (NHS)) over a 5-year time horizon.

Emma Rose McGlone and colleagues report the clinical and cost- effectiveness of bariatric surgery for patients with Type 2 diabetes.