Chronic shift-lag alters the circadian clock of NK cells and promotes lung cancer growth in rats

Prolonged subjection to unstable work or lighting schedules, particularly in rotating shift-workers, is associated with an increased risk of immune-related diseases, including several cancers. Consequences of chronic circadian disruption may also extend to the innate immune system to promote cancer growth, as NK cell function is modulated by circadian mechanisms and plays a key role in lysis of tumor cells. To determine if NK cell function is disrupted by a model of human shift-work and jet-lag, Fischer (344) rats were exposed to either a standard 12:12 light-dark cycle or a chronic shift-lag paradigm consisting of 10 repeated 6-h photic advances occurring every 2 d, followed by 5-7 d of constant darkness. This model resulted in considerable circadian disruption, as assessed by circadian running-wheel activity. NK cells were enriched from control and shifted animals, and gene, protein, and cytolytic activity assays were performed. Chronic shift-lag altered the circadian expression of clock genes, Per2 and Bmal1, and cytolytic factors, perforin and granzyme B, as well as the cytokine, IFN-γ. These alterations were correlated with suppressed circadian expression of NK cytolytic activity. Further, chronic shift-lag attenuated NK cell cytolytic activity under stimulated in vivo conditions, and promoted lung tumor growth following i.v. injection of MADB106 tumor cells. Together, these findings suggest chronic circadian disruption promotes tumor growth by altering the circadian rhythms of NK cell function.     

Th2 cytokines and asthma — Interleukin-9 as a therapeutic target for asthma

Asthma is a complex heritable inflammatory disorder of the airways in which the development of clinical disease depends on environmental exposure. It has been well established that T helper type 2 (T_H2) lymphocytes and their cytokines have an important role in allergic asthma. Interleukin (IL)-9, a member of the T_H2 cytokine family, has recently been implicated as an essential factor in determining mucosal immunity and susceptibility to atopic asthma. In this review we examine the critical experiments and observations that support this hypothesis. We also discuss these results in comparison with the experiments supporting the involvement of other T_H2 cytokines such as IL-4, IL-5 and IL-13.     

How can malaria rapid diagnostic tests achieve their potential? A qualitative study of a trial at health facilities in Ghana

Malaria is still a major public health problem in Brazil, with approximately 306 000 registered cases in 2009, but it is estimated that in the early 1940s, around six million cases of malaria occurred each year. As a result of the fight against the disease, the number of malaria cases decreased over the years and the smallest numbers of cases to-date were recorded in the 1960s. From the mid-1960s onwards, Brazil underwent a rapid and disorganized settlement process in the Amazon and this migratory movement led to a progressive increase in the number of reported cases. Although the main mosquito vector (Anopheles darlingi) is present in about 80% of the country, currently the incidence of malaria in Brazil is almost exclusively (99,8% of the cases) restricted to the region of the Amazon Basin, where a number of combined factors favors disease transmission and impair the use of standard control procedures. Plasmodium vivax accounts for 83,7% of registered cases, while Plasmodium falciparum is responsible for 16,3% and Plasmodium malariae is seldom observed. Although vivax malaria is thought to cause little mortality, compared to falciparum malaria, it accounts for much of the morbidity and for huge burdens on the prosperity of endemic communities. However, in the last few years a pattern of unusual clinical complications with fatal cases associated with P. vivax have been reported in Brazil and this is a matter of concern for Brazilian malariologists. In addition, the emergence of P. vivax strains resistant to chloroquine in some reports needs to be further investigated. In contrast, asymptomatic infection by P. falciparum and P. vivax has been detected in epidemiological studies in the states of Rondonia and Amazonas, indicating probably a pattern of clinical immunity in both autochthonous and migrant populations. Seropidemiological studies investigating the type of immune responses elicited in naturally-exposed populations to several malaria vaccine candidates in Brazilian populations have also been providing important information on whether immune responses specific to these antigens are generated in natural infections and their immunogenic potential as vaccine candidates. The present difficulties in reducing economic and social risk factors that determine the incidence of malaria in the Amazon Region render impracticable its elimination in the region. As a result, a malaria-integrated control effort - as a joint action on the part of the government and the population - directed towards the elimination or reduction of the risks of death or illness, is the direction adopted by the Brazilian government in the fight against the disease.     

Reliability of computerized image analysis for the evaluation of serial synovial biopsies in randomized controlled trials in rheumatoid arthritis

Analysis of biomarkers in synovial tissue is increasingly used in the evaluation of new targeted therapies for patients with rheumatoid arthritis (RA). This study determined the intrarater and inter-rater reliability of digital image analysis (DIA) of synovial biopsies from RA patients participating in clinical trials. Arthroscopic synovial biopsies were obtained before and after treatment from 19 RA patients participating in a randomized controlled trial with prednisolone. Immunohistochemistry was used to detect CD3⁺ T cells, CD38⁺ plasma cells and CD68⁺ macrophages. The mean change in positive cells per square millimetre for each marker was determined by different operators and at different times using DIA. Nonparametric tests were used to determine differences between observers and assessments, and to determine changes after treatment. The intraclass correlations (ICCs) were calculated to determine the intrarater and inter-rater reliability. Intrarater ICCs showed good reliability for measuring changes in T lymphocytes (R = 0.87), plasma cells (R = 0.62) and macrophages (R = 0.73). Analysis by Bland–Altman plots showed no systemic differences between measurements. The smallest detectable changes were calculated and their discriminatory power revealed good response in the prednisolone group compared with the placebo group. Similarly, inter-rater ICCs also revealed good reliability for measuring T lymphocytes (R = 0.68), plasma cells (R = 0.69) and macrophages (R = 0.72). All measurements identified the same cell types as changing significantly in the treated patients compared with the placebo group. The measurement of change in total positive cell numbers in synovial tissue can be determined reproducibly for various cell types by DIA in RA clinical trials.     

Distinct intracellular signaling mediates C‐MET regulation of dendritic growth and synaptogenesis

Hepatocyte growth factor (HGF) activation of the MET receptor tyrosine kinase influences multiple neurodevelopmental processes. Evidence from human imaging and mouse models shows that, in the forebrain, disruptions in MET signaling alter circuit formation and function. One likely means of modulation is by controlling neuron maturation. Here, we examined the signaling mechanisms through which MET exerts developmental effects in the neocortex. In situ hybridization revealed that hgf is located near MET‐expressing neurons, including deep neocortical layers and periventricular zones. Western blot analyses of neocortical crude membranes demonstrated that HGF‐induced MET autophosphorylation peaks during synaptogenesis, with a striking reduction in activation between P14 and P17 just before pruning. In vitro analysis of postnatal neocortical neurons assessed the roles of intracellular signaling following MET activation. There is rapid, HGF‐induced phosphorylation of MET, ERK1/2, and Akt that is accompanied by two major morphological changes: increases in total dendritic growth and synapse density. Selective inhibition of each signaling pathway altered only one of the two distinct events. MAPK/ERK pathway inhibition significantly reduced the HGF‐induced increase in dendritic length, but had no effect on synapse density. In contrast, inhibition of the PI3K/Akt pathway reduced HGF‐induced increases in synapse density, with no effect on dendritic length. The data reveal a key role for MET activation during the period of neocortical neuron growth and synaptogenesis, with distinct biological outcomes mediated via discrete MET‐linked intracellular signaling pathways in the same neurons. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1160–1181, 2016     

Dopamine-beta-hydroxylase activity in plasma obtained from the pulmonary artery and left ventricle of man

Dopamine-β-hydroxylase activity (DBH) has been measured in plasma obtained simultaneously from the pulmonary artery and left ventricle of fourteen patients who underwent diagnostic cardiac catheterisation. In the majority of these subjects the levels of enzyme activity in the arterial and venous blood were similar, indicating that inactivation of DBH had not occurred in its passage through the pulmonary circulation. One patient with pulmonary hypertension had a large a-v difference in enzyme activity that may have been caused by altered pulmonary haemodynamics. Three of the five subjects that undertook a standardised exercise test on a bicycle ergometer showed a significant increase in plasma DBH activity. There was no correlation between the increases in DBH activity and in cardiac index and heart rate.