Type II and VI collagen in nasal and articular cartilage and the effect of IL-1α on the distribution of these collagens

The distribution of type II and VI collagen was immunocytochemically investigated in bovine articular and nasal cartilage. Cartilage explants were used either fresh or cultured for up to 4 weeks with or without interleukin 1α (IL-1α). Sections of the explants were incubated with antibodies for both types of collagen. Microscopic analyses revealed that type II collagen was preferentially localized in the interchondron matrix whereas type VI collagen was primarily found in the direct vicinity of the chondrocytes. Treatment of the sections with hyaluronidase greatly enhanced the signal for both types of collagen. Also in sections of explants cultured with IL-1α a higher level of labeling of the collagens was found. This was apparent without any pre-treatment with hyaluronidase. Under the influence of IL-1α the area positive for type VI collagen that surrounded the chondrocytes broadened. Although the two collagens in both types of cartilage were distributed similarly, a remarkable difference was the higher degree of staining of type VI collagen in articular cartilage. Concomitantly we noted that digestion of this type of cartilage hardly occurred in the presence of IL-1α whereas nasal cartilage was almost completely degraded within 18 days of culture. Since type VI collagen is known to be relatively resistant to proteolysis we speculate that the higher level of type VI collagen in articular cartilage is important in protecting cartilage from digestion

Deficiency in the autophagy modulator Dram1 exacerbates pyroptotic cell death of Mycobacteria-infected macrophages

DNA damage regulated autophagy modulator 1 (DRAM1) is a stress-inducible regulator of autophagy and cell death. DRAM1 has been implicated in cancer, myocardial infarction, and infectious diseases, but the molecular and cellular functions of this transmembrane protein remain poorly understood. Previously, we have proposed DRAM1 as a host resistance factor for tuberculosis (TB) and a potential target for host-directed anti-infective therapies. In this study, we generated a zebrafish dram1 mutant and investigated its loss-of-function effects during Mycobacterium marinum (Mm) infection, a widely used model in TB research. In agreement with previous knockdown analysis, dram1 mutation increased the susceptibility of zebrafish larvae to Mm infection. RNA sequencing revealed major effects of Dram1 deficiency on metabolic, immune response, and cell death pathways during Mm infection, and only minor effects on proteinase and metabolic pathways were found under uninfected conditions. Furthermore, unchallenged dram1 mutants did not display overt autophagic defects, but autophagic targeting of Mm was reduced in the absence of Dram1. The phagocytic ability of macrophages in dram1 mutants was unaffected, but acidification of Mm-containing vesicles was strongly reduced, indicating that Dram1 is required for phagosome maturation. By in vivo imaging, we observed that Dram1-deficient macrophages fail to restrict Mm during early stages of infection. The resulting increase in bacterial burden could be reverted by knockdown of inflammatory caspase a (caspa) and gasdermin Eb (gsdmeb), demonstrating pyroptosis as the mechanism underlying premature cell death of Mm-infected macrophages in dram1 mutants. Collectively, these data demonstrate that dissemination of mycobacterial infection in zebrafish larvae is promoted in the absence of Dram1 due to reduced maturation of mycobacteria-containing vesicles, failed intracellular containment, and consequent pyroptotic death of infected macrophages. These results provide new evidence that Dram1 plays a central role in host resistance to intracellular infection, acting at the crossroad of autophagy and cell death

Mycobacteria counteract a TLR-mediated nitrosative defense mechanism in a zebrafish infection model.

Pulmonary tuberculosis (TB), caused by the intracellular bacterial pathogen Mycobacterium tuberculosis (Mtb), is a major world health problem. The production of reactive nitrogen species (RNS) is a potent cytostatic and cytotoxic defense mechanism against intracellular pathogens. Nevertheless, the protective role of RNS during Mtb infection remains controversial. Here we use an anti-nitrotyrosine antibody as a readout to study nitration output by the zebrafish host during early mycobacterial pathogenesis. We found that recognition of Mycobacterium marinum, a close relative of Mtb, was sufficient to induce a nitrosative defense mechanism in a manner dependent on MyD88, the central adaptor protein in Toll like receptor (TLR) mediated pathogen recognition. However, this host response was attenuated by mycobacteria via a virulence mechanism independent of the well-characterized RD1 virulence locus. Our results indicate a mechanism of pathogenic mycobacteria to circumvent host defense in vivo. Shifting the balance of host-pathogen interactions in favor of the host by targeting this virulence mechanism may help to alleviate the problem of infection with Mtb strains that are resistant to multiple drug treatments

Statistical design and analysis in trials of proportionate interventions: a systematic review

Background: In proportionate or adaptive interventions, the dose or intensity can be adjusted based on individual need at predefined decision stages during the delivery of the intervention. The development of such interventions may require an evaluation of the effectiveness of the individual stages in addition to the whole intervention. However, evaluating individual stages of an intervention has various challenges, particularly the statistical design and analysis. This review aimed to identify the use of trials of proportionate interventions and how they are being designed and analysed in current practice. Methods: We searched MEDLINE, Web of Science and PsycINFO for articles published between 2010 and 2015 inclusive. We considered trials of proportionate interventions in all fields of research. For each trial, its aims, design and analysis were extracted. The data synthesis was conducted using summary statistics and a narrative format. Results: Our review identified 44 proportionate intervention trials, comprising 28 trial results, 13 protocols and three secondary analyses. These were mostly described as stepped care (n=37) and mainly focussed on mental health research (n=30). The other studies were aimed at finding an optimal adaptive treatment strategy (n=7) in a variety of therapeutic areas. Further terminology used included adaptive intervention, staged intervention, sequentially multiple assignment trial or a two-phase design. The median number of decision stages in the interventions was two and only one study explicitly evaluated the effect of the individual stages. Conclusions: Trials of proportionate staged interventions are being used predominantly within the mental health field. However, few studies consider the different stages of the interventions, either at the design or the analysis phase, and how they may interact with one another. There is a need for further guidance on the design, analyses and reporting across trials of proportionate interventions

[Definition study: Source-risk model for radon.]

A definition study for the development of a model describing the complete chain ; source -> exhalation -> dispersion -> exposure -> effect/risk for radon is performed. The purpose of a source-risk model is to support policy making on radon mitigation by comparing effects of various policy options and to enable optimisation of counter measures applied to different parts of the source-risk chain. There are several advantages developing and using a source-risk model. - Risk calculations are standardized. The calculations are done with most appropriate models available at a moment. Parameter values are used consistently in the entire source-risk chain. - The effects of measures applied to different parts of the source-risk chain can be better compared because interactions are included. - Sensitivity analyses can be used to determine the most important parameters within the total source-risk chain. After making up an inventory of processes and sources to be included in the source-risk chain, we investigated the models presently available in the Netherlands by interviewing several owners of models. The models were screened for completeness, validation and operational status. The investigation made clear that, by choosing for each part of the source-risk chain the most convenient model, a source-risk chain model for radon may be realised. However, the calculation of dose out of the radon concentrations and the status of the validation of most models should be improved. Calculations with the proposed source-risk model will give estimations with a large uncertainty at the moment. Still, realisation of the proposed source-risk model is recommended because the investigations made clear that the use of a source-risk model will have a surplus value over the use of single models. For further development of the source-risk model an interaction between the source-risk model and experimental research is recommended.NOVE

[Research programme on the presence and consequences of enhanced levels of Ra-226 in polders where harbour sludge was used as landfill - Definition report.]

Abstract niet beschikbaarIn this study on three construction sites in the Rijnmond area (around the Rotterdam harbour) which were elevated with dredged sediment from the New Waterway area, the radium level of the soil has been determined and data on the groundwater level and the thickness of the (natural) soil horizon have been collected. On all the sites the average radium level was found to be above 60 Bq/kg. The calculated radium levels ranged from 54-143 Bq/kg for Spaland to 90-96 Bq/kg for Stormpolder-Noord. There is no clear explanation for the large variation in the results. For the Spaland site the available data show that the groundwater level in the built-up section remains constantly above the dredged sediment-soil horizon interface. For the Stormpolder-Noord (built-up section) site the groundwater level is found below the soil horizon. Data collected in 1990-1992 show that for part of the year the groundwater level for the site in Spijkenisse remains below the soil horizon-dredged sediment interface.DGM/SV

Interim measuring method for the radon exhalation of building materials

In het Beleidsstandpunt Radon kiest het Ministerie van VROM voor een stand-still tot 1996, gevolgd door een reductie, van de risico's door radon en gammastraling uit bouwmaterialen. Op verzoek van de Directie Stoffen, Veiligheid en Straling van VROM/DGM heeft het RIVM advies uitgebracht over een interim-methode voor het meten van de radonexhalatie van bouwprodukten. Als meetmethode wordt de voorkeur gegeven aan het principe van de drukvrije exhalatiekamer, met een doorgaande stikstofstroom en een radonabsorber in de uitgaande gasstroom. Dit principe benadert het beste de vrije, diffusiegestuurde exhalatie. Tevens wordt, vanwege de betere aansluiting bij de praktijk-situatie, gekozen voor het meten van de een-dimensionale exhalatie van monsters bouwprodukt geconditioneerd bij 50% relatieve vochtigheid en 20 graden C. Aanbevolen wordt door middel van modelberekeningen en praktijkonderzoek het belang van drukgestuurde radonexhalatie vast te stellen. Voorts wordt een aantal aanbevelingen gedaan op het terrein van vergroting van de kennis over radonexhalatie, kwaliteitsborging van de meetmethode en het waarborgen van de optimale bruikbaarheid van de verkregen meetresultaten. Na publikatie van een Nederlandse Voornorm terzake (NVN 5699), naar verwachting medio 1995, vervalt dit RIVM-advies en dient NVN 5699 te worden toegepast bij het meten van de radonexhalatie van bouwprodukten.In the framework of its Policy Paper on Radon, the Ministry of Housing, Physical Planning and Environment (VROM) has chosen for a stand-still until 1996, followed by a future reduction, of the radiation risks due to radon and gamma radiation originating from building materials. Standard methods for the determination of the radon exhalation are lacking. RIVM has been asked by the VROM Directorate of Substances, External Safety and Radiation (VROM/DGM/SVS) to advise on such a measuring method. This report recommends using the principle of a pressure-free exhalation chamber as a measuring method, in which a continuous nitrogen flow and a radon absorber in the outgoing flow is applied. This principle gives the best approximation of free, diffusion-controlled radon exhalation. Furthermore, one-dimensional exhalation has been concluded to best simulate common building practices. Measuring of samples conditioned at 50% relative humidity and 20 degrees C is proposed as a standard. Additional research on the importance of pressure-driven exhalation, using model calculations and laboratory tests, is recommended. Further research, quality assurance of the measurement method and optimalization of the use of measuring data are also advised. After publication of pre-standard NVN 5699 by the Netherlands Normalization Institute, which is expected in 1995, this interim method will expire and NVN 5699 will have to be used in exhalation measurements.DGM/SV