Increased high-latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition.

Arctic and boreal ecosystems play an important role in the global carbon (C) budget, and whether they act as a future net C sink or source depends on climate and environmental change. Here, we used complementary in situ measurements, model simulations, and satellite observations to investigate the net carbon dioxide (CO2 ) seasonal cycle and its climatic and environmental controls across Alaska and northwestern Canada during the anomalously warm winter to spring conditions of 2015 and 2016 (relative to 2010-2014). In the warm spring, we found that photosynthesis was enhanced more than respiration, leading to greater CO2 uptake. However, photosynthetic enhancement from spring warming was partially offset by greater ecosystem respiration during the preceding anomalously warm winter, resulting in nearly neutral effects on the annual net CO2 balance. Eddy covariance CO2 flux measurements showed that air temperature has a primary influence on net CO2 exchange in winter and spring, while soil moisture has a primary control on net CO2 exchange in the fall. The net CO2 exchange was generally more moisture limited in the boreal region than in the Arctic tundra. Our analysis indicates complex seasonal interactions of underlying C cycle processes in response to changing climate and hydrology that may not manifest in changes in net annual CO2 exchange. Therefore, a better understanding of the seasonal response of C cycle processes may provide important insights for predicting future carbon-climate feedbacks and their consequences on atmospheric CO2 dynamics in the northern high latitudes.

Changing the Paradigm of Daily Prevention to Achieve Whole Mouth Health in the 21st Century.

A comprehensive mechanical plaque control program - designed, monitored, and reinforced by dental professionals - can help patients achieve excellent oral hygiene and oral health. However, this approach to prevention is impractical for many individuals, so dental caries and periodontal disease are highly prevalent globally. Experts recently agreed that a toothpaste with fluoride and a plaque control agent can augment mechanical procedures to simultaneously prevent caries and periodontal disease. Notwithstanding this, it is timely to rethink prevention and oral health promotion. A new definition of oral health raises awareness of its different dimensions and empowers dentistry to move from treating disease to supporting prevention. In addition, a deeper understanding of the relationship between oral biofilms and the host facilitates new opportunities for disease prevention. The knowledge that health-associated biofilms help prevent establishment of pathogenic species, regulate the potentially damaging host response, and provide essential benefits to health and well-being is paramount to changing the paradigm of prevention of dental disease. Ecological approaches to biofilm control can reduce plaque sufficiently to reduce disease risk, while creating and supporting the beneficial functions of biofilms consistent with health. The knowledge that the oral soft tissues are the primary reservoir of bacteria for tooth recolonization and that reducing bacteria on soft tissues results in improved plaque control and consequently better oral health is also salient. Indeed, a toothpaste that delivers 12-hour protection to the hard and soft tissues (whole mouth protection) and multiple oral health benefits (whole mouth health) could become the future cornerstone of prevention. An innovative fluoride toothpaste with a Dual Zinc plus Arginine multi-functional therapeutic agent offers whole mouth protection against daily oral challenges and whole mouth health for the patient. Within a patient-centered preventive program, next to messaging that motivates towards improved self-care, this toothpaste empowers patients to achieve effective prevention of common oral diseases and better oral health compared to just brushing with an ordinary toothpaste.

Ecological Therapeutic Opportunities for Oral Diseases.

The three main oral diseases of humans, that is, caries, periodontal diseases, and oral candidiasis, are associated with microbiome shifts initiated by changes in the oral environment and/or decreased effectiveness of mucosal immune surveillance. In this review, we discuss the role that microbial-based therapies may have in the control of these conditions. Most investigations on the use of microorganisms for management of oral disease have been conducted with probiotic strains with some positive but very discrete clinical outcomes. Other strategies such as whole oral microbiome transplantation or modification of community function by enrichment with health-promoting indigenous oral strains may offer more promise, but research in this field is still in its infancy. Any microbial-based therapeutics for oral conditions, however, are likely to be only one component within a holistic preventive strategy that should also aim at modification of the environmental influences responsible for the initiation and perpetuation of microbiome shifts associated with oral dysbiosis.

Coffee Intake Is Associated with a Lower Liver Stiffness in Patients with Non-Alcoholic Fatty Liver Disease, Hepatitis C, and Hepatitis B.

There is emerging evidence for the positive effects or benefits of coffee in patients with liver disease. We conducted a retrospective cross-sectional study on patients with non-alcoholic fatty liver disease (NAFLD), hepatitis C virus (HCV), and hepatitis B virus (HBV) infection to determine the effects of coffee intake on a non-invasive marker of liver fibrosis: liver stiffness assessed by transient elastography (TE). We assessed coffee and tea intake and measured TE in 1018 patients with NAFLD, HCV, and HBV (155 with NAFLD, 378 with HCV and 485 with HBV). Univariate and multivariate regression models were performed taking into account potential confounders. Liver stiffness was higher in males compared to females (p < 0.05). Patients with HBV had lower liver stiffness than those with HCV and NAFLD. After adjustment for age, gender, smoking, alcohol consumption, M or XL probe, and disease state (NAFLD, HCV, and HBV status), those who drank 2 or more cups of coffee per day had a lower liver stiffness (p = 0.044). Tea consumption had no effect (p = 0.9). Coffee consumption decreases liver stiffness, which may indicate less fibrosis and inflammation, independent of disease state. This study adds further evidence to the notion of coffee maybe beneficial in patients with liver disease.

Sorafenib in the treatment of hepatocellular carcinoma: a multi-centre real-world study.

OBJECTIVE: Sorafenib is an oral multikinase inhibitor that improves survival in advanced hepatocellular carcinoma (HCC). In the absence of alternative therapies, sorafenib is often continued despite advancing liver disease or tumour progression. Real world studies are important to better characterise outcomes in these populations. Our aim was to review patterns of sorafenib use across eight Australian tertiary hospitals, defining variables associated with clinical outcomes. MATERIAL AND METHODS: Retrospective cohort study of medical records of 320 patients treated with sorafenib for HCC. Baseline clinical parameters, dosage, adverse effects, and survival from initiation of treatment were collected. Time to radiological progression and 3-month alpha-fetoprotein (AFP) levels were available for a subset of patients. RESULTS: Adverse effects occurred in 79% of patients, requiring dose reduction in 31% of patients. Multivariate analysis identified an increased rate of mortality with Child-Pugh C (HR 5.52, p = 0.012), ECOG performance status 2-3 (HR 2.84, p = 0.001), and extrahepatic metastases (HR 1.54, p = 0.04), and decreased rate of mortality with an AFP reduction of at least 20% at 3 months (HR 0.38, p = 0.001). An increased rate of radiological progression was associated with ECOG performance status 2-3 (HR 2.34, p = 0.041), whilst a decreased rate of radiological progression was associated with development of on-treatment diarrhoea (HR 0.55, p = 0.015). CONCLUSIONS: Survival in patients with Child-Pugh C liver function or advanced functional impairment treated with sorafenib is poor and thus routine use of this agent in these patients does not appear justified, particularly given the high rate of adverse effects. AFP concentration on therapy may help identify favourable response to treatment.

Mycobacterium tuberculosis Is Resistant to Isoniazid at a Slow Growth Rate by Single Nucleotide Polymorphisms in katG Codon Ser315.

An important aim for improving TB treatment is to shorten the period of antibiotic therapy without increasing relapse rates or encouraging the development of antibiotic-resistant strains. In any M. tuberculosis population there is a proportion of bacteria that are drug-tolerant; this might be because of pre-existing populations of slow growing/non replicating bacteria that are protected from antibiotic action due to the expression of a phenotype that limits drug activity. We addressed this question by observing populations of either slow growing (constant 69.3h mean generation time) or fast growing bacilli (constant 23.1h mean generation time) in their response to the effects of isoniazid exposure, using controlled and defined growth in chemostats. Phenotypic differences were detected between the populations at the two growth rates including expression of efflux mechanisms and the involvement of antisense RNA/small RNA in the regulation of a drug-tolerant phenotype, which has not been explored previously for M. tuberculosis. Genotypic analyses showed that slow growing bacilli develop resistance to isoniazid through mutations specifically in katG codon Ser315 which are present in approximately 50-90% of all isoniazid-resistant clinical isolates. The fast growing bacilli persisted as a mixed population with katG mutations distributed throughout the gene. Mutations in katG codon Ser315 appear to have a fitness cost in vitro and particularly in fast growing cultures. Our results suggest a requirement for functional katG-encoded catalase-peroxide in the slow growers but not the fast-growing bacteria, which may explain why katG codon Ser315 mutations are favoured in the slow growing cultures.

Transcriptional responses of Mycobacterium tuberculosis exposed to adverse conditions in vitro.

Mycobacterium tuberculosis encounters a range of stimuli in the host. Understanding the environmental cues that initiate the transcriptional response of M. tuberculosis, which enable the bacterium to replicate and/or survive in the host, will provide markers that are specific to different stages of disease, further refining the search for improved treatments and vaccines. Studying M. tuberculosis gene expression in vivo is technically challenging and more amenable in vitro experiments are being used to aid interpretation and to dissect the signals that are responsible for controlling subsets of genes. Key parameters that affect the growth of a pathogen in the host include nutrient status, environmental pH, oxygen availability, and host defences. Studying gene expression, pathogenicity, and physiology of M. tuberculosis that has been exposed to these relevant host conditions in vitro will further increase our understanding of the virulence factors that M. tuberculosis requires to establish disease. Complementary information obtained by metabolic flux analysis, proteomics, and regulatory networks analysis will enable a clearer picture of how transcriptional responses translate to changes in the metabolome and physiology of the organism.

Dental plaque as a biofilm and a microbial community - implications for health and disease.

Dental plaque is a structurally- and functionally-organized biofilm. Plaque forms in an ordered way and has a diverse microbial composition that, in health, remains relatively stable over time (microbial homeostasis). The predominant species from diseased sites are different from those found in healthy sites, although the putative pathogens can often be detected in low numbers at normal sites. In dental caries, there is a shift toward community dominance by acidogenic and acid-tolerating species such as mutans streptococci and lactobacilli, although other species with relevant traits may be involved. Strategies to control caries could include inhibition of biofilm development (e.g. prevention of attachment of cariogenic bacteria, manipulation of cell signaling mechanisms, delivery of effective antimicrobials, etc.), or enhancement of the host defenses. Additionally, these more conventional approaches could be augmented by interference with the factors that enable the cariogenic bacteria to escape from the normal homeostatic mechanisms that restrict their growth in plaque and out compete the organisms associated with health. Evidence suggests that regular conditions of low pH in plaque select for mutans streptococci and lactobacilli. Therefore, the suppression of sugar catabolism and acid production by the use of metabolic inhibitors and non-fermentable artificial sweeteners in snacks, or the stimulation of saliva flow, could assist in the maintenance of homeostasis in plaque. Arguments will be presented that an appreciation of ecological principles will enable a more holistic approach to be taken in caries control.

Evaluation of vaccines in the EU TB Vaccine Cluster using a guinea pig aerosol infection model of tuberculosis.

The TB Vaccine Cluster project funded by the EU Fifth Framework programme aims to provide novel vaccines against tuberculosis that are suitable for evaluation in humans. This paper describes the studies of the protective efficacy of vaccines in a guinea pig aerosol-infection model of primary tuberculosis. The objective was to conduct comparative evaluations of vaccines that had previously demonstrated efficacy in other animal models. Groups of 6 guinea pigs were immunized with vaccines provided by the relevant EU Vaccine Cluster partners. Survival over 17 or 26 weeks was used as the principal measure of vaccine efficacy following aerosol challenge with H37Rv. Counts of mycobacteria in lungs and spleens, and histopathological changes in the lungs, were also used to provide evidence of protection. A total of 24 vaccines were evaluated in 4 experiments each of a different design. A heterologous prime-boost strategy of DNA and MVA, each expressing Ag85A and a fusion protein of ESAT-6 and Ag85B in adjuvant, protected the guinea pigs to the same extent as BCG. Genetically modified BCG vaccines and boosted BCG strategies also protected guinea pigs to the same extent as BCG but not statistically significantly better. A relatively high aerosol-challenge dose and evaluation over a protracted time post-challenge allowed superior protection over BCG to be demonstrated by BCG boosted with MVA and fowl pox vectors expressing Ag85A.