Recent reports show ethylene-dependent reductions in stomatal sensitivity to abscisic acid (ABA) under ozone stress. These changes reduce stomatal control of plant water loss in drying soil. Here we ...review evidence that ABA and ethylene, and interactions between these two stress-induced hormones, control many of the responses of intact plants to drought and ozone stress, with emphasis on effects on stomata and shoot growth. We draw attention to convergent signalling and response pathways induced by ozone and drought that can increase production of hydrogen peroxide (H₂O₂) and nitric oxide (NO). Stomatal responses to a wider range of stresses and developmental cues may also be controlled via the same sets of signalling pathways. Other hormones, or effectors such as xylem/apoplastic pH or changes in plant water status, also play a role in signalling within and between organs. We discuss the implications, for crops, natural ecosystems and water catchment processes, of ethylene's antagonism of the stomatal response to ABA, against a back-drop of predictions for reduced precipitation and increasing ozone pollution, as part of global climate change and increasing urbanization and industrial development.
•Lytic polysaccharide monooxygenases are newly discovered copper oxygenases.•LPMOs open up new thinking about oxidation mechanisms.•Copper histidine brace active site is challenging precepts in ...bioinorganic chemistry.•The catalytic mechanism of LPMOs is an area of intense study.•LPMOs are important factors in commercial biofuel production.
Lytic polysaccharide monooxygenases (LPMOs) are recently discovered copper-containing oxygenases. LPMOs oxidise recalcitrant polysaccharides such as chitin and cellulose, thereby making these substrates more tractable to canonical chitinase or cellulase action. As such, LPMOs are attracting much attention not only for their capacity to greatly increase the efficiency of production of cellulosic-based biofuels, but also for the new questions they pose about the mechanisms of biological oxidation of recalcitrant substrates. This review draws together the current thinking on the catalytic mechanisms of LPMOs and other copper catalysed oxygenations and provides a blueprint for further investigation into the mechanisms of action of these intriguing enzymes.
Summary
While many women with polycystic ovary syndrome (PCOS) are overweight, obese or centrally obese, the effect of excess weight on the outcomes of PCOS is inconsistent. The review aimed to ...assess the effects of overweight, obesity and central obesity on the reproductive, metabolic and psychological features of PCOS. MEDLINE, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials (CENTRAL) and PSYCINFO were searched for studies reporting outcomes according to body mass index categories or body fat distribution. Data were presented as mean difference or risk ratio (95% confidence interval). This review included 30 eligible studies. Overweight or obese women with PCOS had decreased sex hormone‐binding globulin (SHBG), increased total testosterone, free androgen index, hirsutism, fasting glucose, fasting insulin, homeostatic model assessment‐insulin resistance index and worsened lipid profile. Obesity significantly worsened all metabolic and reproductive outcomes measured except for hirsutism when compared to normal weight women with PCOS. Overweight women had no differences in total testosterone, hirsutism, total‐cholesterol and low‐density lipoprotein‐cholesterol compared to normal weight women and no differences in SHBG and total testosterone compared to obese women. Central obesity was associated with higher fasting insulin levels. These results suggest that prevention and treatment of obesity is important for the management of PCOS.
Summary
Grass pollens of the temperate (Pooideae) subfamily and subtropical subfamilies of grasses are major aeroallergen sources worldwide. The subtropical Chloridoideae (e.g. Cynodon dactylon; ...Bermuda grass) and Panicoideae (e.g. Paspalum notatum; Bahia grass) species are abundant in parts of Africa, India, Asia, Australia and the Americas, where a large and increasing proportion of the world's population abide. These grasses are phylogenetically and ecologically distinct from temperate grasses. With the advent of global warming, it is conceivable that the geographic distribution of subtropical grasses and the contribution of their pollen to the burden of allergic rhinitis and asthma will increase. This review aims to provide a comprehensive synthesis of the current global knowledge of (i) regional variation in allergic sensitivity to subtropical grass pollens, (ii) molecular allergenic components of subtropical grass pollens and (iii) allergic responses to subtropical grass pollen allergens in relevant populations. Patients from subtropical regions of the world show higher allergic sensitivity to grass pollens of Chloridoideae and Panicoideae grasses, than to temperate grass pollens. The group 1 allergens are amongst the allergen components of subtropical grass pollens, but the group 5 allergens, by which temperate grass pollen extracts are standardized for allergen content, appear to be absent from both subfamilies of subtropical grasses. Whilst there are shared allergenic components and antigenic determinants, there are additional clinically relevant subfamily‐specific differences, at T‐ and B‐cell levels, between pollen allergens of subtropical and temperate grasses. Differential immune recognition of subtropical grass pollens is likely to impact upon the efficacy of allergen immunotherapy of patients who are primarily sensitized to subtropical grass pollens. The literature reviewed herein highlights the clinical need to standardize allergen preparations for both types of subtropical grass pollens to achieve optimal diagnosis and treatment of patients with allergic respiratory disease in subtropical regions of the world.
The American Diabetes Association and the European Association for the Study of Diabetes have briefly updated their 2018 recommendations on management of hyperglycaemia, based on important research ...findings from large cardiovascular outcomes trials published in 2019. Important changes include: (1) the decision to treat high-risk individuals with a glucagon-like-peptide 1 (GLP-1) receptor agonist or sodium–glucose cotransporter 2 (SGLT2) inhibitor to reduce major adverse cardiovascular events (MACE), hospitalisation for heart failure (hHF), cardiovascular death or chronic kidney disease (CKD) progression should be considered independently of baseline HbA
1c
or individualised HbA
1c
target; (2) GLP-1 receptor agonists can also be considered in patients with type 2 diabetes without established cardiovascular disease (CVD) but with the presence of specific indicators of high risk; and (3) SGLT2 inhibitors are recommended in patients with type 2 diabetes and heart failure, particularly those with heart failure with reduced ejection fraction, to reduce hHF, MACE and CVD death, as well as in patients with type 2 diabetes with CKD (eGFR 30 to ≤60 ml min
−1
1.73 m
−2
or urinary albumin-to-creatinine ratio >30 mg/g, particularly >300 mg/g) to prevent the progression of CKD, hHF, MACE and cardiovascular death.
The American Diabetes Association and the European Association for the Study of Diabetes convened a panel to update the prior position statements, published in 2012 and 2015, on the management of ...type 2 diabetes in adults. A systematic evaluation of the literature since 2014 informed new recommendations. These include additional focus on lifestyle management and diabetes self-management education and support. For those with obesity, efforts targeting weight loss, including lifestyle, medication, and surgical interventions, are recommended. With regards to medication management, for patients with clinical cardiovascular disease, a sodium-glucose cotransporter 2 (SGLT2) inhibitor or a glucagon-like peptide 1 (GLP-1) receptor agonist with proven cardiovascular benefit is recommended. For patients with chronic kidney disease or clinical heart failure and atherosclerotic cardiovascular disease, an SGLT2 inhibitor with proven benefit is recommended. GLP-1 receptor agonists are generally recommended as the first injectable medication.
Pacific oysters are now one of the most ‘globalised’ marine invertebrates. They dominate bivalve aquaculture production in many regions and wild populations are increasingly becoming established, ...with potential to displace native species and modify habitats and ecosystems. While some fishing communities may benefit from wild populations, there is now a tension between the continued production of Pacific oysters and risk to biodiversity, which is of particular concern within protected sites. The issue of the Pacific oyster therefore locates at the intersection between two policy areas: one concerning the conservation of protected habitats, the other relating to livelihoods and the socio-economics of coastal aquaculture and fishing communities. To help provide an informed basis for management decisions, we first summarise evidence for ecological impacts of wild Pacific oysters in representative coastal habitats. At local scales, it is clear that establishment of Pacific oysters can significantly alter diversity, community structure and ecosystem processes, with effects varying among habitats and locations and with the density of oysters. Less evidence is available to evaluate regional-scale impacts. A range of management measures have been applied to mitigate negative impacts of wild Pacific oysters and we develop recommendations which are consistent with the scientific evidence and believe compatible with multiple interests. We conclude that all stakeholders must engage in regional decision making to help minimise negative environmental impacts, and promote sustainable industry development.
Aim
To assess the comparative efficacy and safety of sodium‐glucose co‐transporter‐2 (SGLT2) inhibitors in adults with type 2 diabetes.
Methods
We electronically searched randomized controlled trials ...(≥24 weeks) including canagliflozin, dapagliflozin or empagliflozin that were published up to 3 November 2015. Data were collected on cardiometabolic and safety outcomes and synthesized using network meta‐analyses.
Results
A total of 38 trials (23 997 participants) were included. Compared with placebo, all SGLT2 inhibitors reduced glycated haemoglobin (HbA1c), fasting plasma glucose (FPG), body weight and blood pressure, and slightly increased HDL cholesterol. Canagliflozin 300 mg reduced HbA1c, FPG and systolic blood pressure and increased LDL cholesterol to a greater extent compared with other inhibitors at any dose. At their highest doses, canagliflozin 300 mg reduced: HbA1c by 0.2% 95% confidence interval (CI) 0.1–0.3 versus both dapagliflozin 10 mg and empagliflozin 25 mg; FPG by 0.6 mmol/l (95% CI 0.3–0.9) and 0.5 mmol/l (95% CI 0.1–0.8) versus dapagliflozin and empagliflozin, respectively; and systolic blood pressure by 2 mmHg (95% CI 1.0–3.0) versus dapagliflozin; and increased LDL cholesterol by 0.13 mmol/l (95% CI 0.03–0.23) and 0.15 mmol/l (95% CI 0.06–0.23) versus dapagliflozin and empagliflozin, respectively. The highest doses of inhibitors had similar effects on body weight reduction. Canagliflozin 300 and 100 mg increased the risk of hypoglycaemia versus placebo, dapagliflozin 10 mg and empagliflozin 10 mg odds ratios (ORs) 1.4–1.6. Dapagliflozin 10 mg increased the risk of urinary tract infection versus placebo and empagliflozin 25 mg (ORs 1.4). All inhibitors similarly increased the risk of genital infection (ORs 4–6 versus placebo).
Conclusions
Although they increase the risk of genital infection, SGLT2 inhibitors are effective in improving cardiometabolic markers in type 2 diabetes, with canagliflozin 300 mg performing better in this respect than other inhibitors. Further studies will clarify whether these differences are likely to translate into differing long‐term outcomes.
Diabetes mellitus is a complex metabolic disorder associated with an increased risk of microvascular and macrovascular disease; its main clinical characteristic is hyperglycaemia. The last century ...has been characterised by remarkable advances in our understanding of the mechanisms leading to hyperglycaemia. The central role of insulin in glucose metabolism regulation was clearly demonstrated during the early 1920s, when Banting, Best, Collip and Macleod successfully reduced blood glucose levels and glycosuria in a patient treated with a substance purified from bovine pancreata. Later, during the mid-1930s, clinical observations suggested a possible distinction between 'insulin-sensitive' and 'insulin-insensitive' diabetes. Only during the 1950s, when a reliable measure of circulating insulin was available, was it possible to translate these clinical observations into pathophysiological and biochemical differences, and the terms 'insulin-dependent' (indicating undetectable insulin levels) and 'non-insulin-dependent' (normal or high insulin levels) started to emerge. The next 30 years were characterised by pivotal progress in the field of immunology that were instrumental in demonstrating an immune-mediated loss of insulin-secreting β-cells in subjects with 'insulin-dependent' diabetes. At the same time, new experimental techniques allowing measurement of insulin 'impedance' showed a reduced peripheral effect of insulin in subjects with 'non-insulin-dependent' diabetes (insulin resistance). The difference between the two types of diabetes emerging from decades of observations and experiments was further formally recognised in 1979, when the definitions 'type I' and 'type II' diabetes were introduced to replace the former 'insulin-dependent' and 'non-insulin-dependent' terms. In the following years, many studies elucidated the natural history and temporal contribution of insulin resistance and β-cell insulin secretion in 'type II' diabetes. Furthermore, a central role for insulin resistance in the development of a cluster of cardiometabolic alterations (dyslipidaemia, inflammation, high blood pressure) was suggested. Possibly as a consequence of the secular changes in diabetes risk factors, in the last 10 years the limitation of a simple distinction between 'type I' and 'type II' diabetes has been increasingly recognised, with subjects showing the coexistence of insulin resistance and immune activation against β-cells. With the advancement of our cellular and molecular understanding of diabetes, a more pathophysiological classification that overcomes the historical and simple 'glucocentric' view could result in a better patient phenotyping and therapeutic approach.
Microneedle-based microdevices promise to expand the scope for delivery of vaccines and therapeutic agents through the skin and withdrawing biofluids for point-of-care diagnostics – so-called ...theranostics. Unskilled and painless applications of microneedle patches for blood collection or drug delivery are two of the advantages of microneedle arrays over hypodermic needles. Developing the necessary microneedle fabrication processes has the potential to dramatically impact the health care delivery system by changing the landscape of fluid sampling and subcutaneous drug delivery. Microneedle designs which range from sub-micron to millimetre feature sizes are fabricated using the tools of the microelectronics industry from metals, silicon, and polymers. Various types of subtractive and additive manufacturing processes have been used to manufacture microneedles, but the development of microneedle-based systems using conventional subtractive methods has been constrained by the limitations and high cost of microfabrication technology. Additive manufacturing processes such as 3D printing and two-photon polymerization fabrication are promising transformative technologies developed in recent years. The present article provides an overview of microneedle systems applications, designs, material selection, and manufacturing methods.
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