Treatment-associated polymorphisms in protease are significantly associated with higher viral load and lower CD4 count in newly diagnosed drug-naive HIV-1 infected patients

Background

Bone marrow stromal cell antigen 2 (BST-2) is a cellular factor that restricts the egress of viruses such as human immunodeficiency virus (HIV-1) from the surface of infected cells, preventing infection of new cells. BST-2 is variably expressed in most cell types, and its expression is enhanced by cytokines such as type I interferon alpha (IFN-??). In this present study, we used the beta-retrovirus, mouse mammary tumor virus (MMTV) as a model to examine the role of mouse BST-2 in host infection in vivo.

Results

By using RNA interference, we show that loss of BST-2 enhances MMTV replication in cultured mammary tumor cells and in vivo. In cultured cells, BST-2 inhibits virus accumulation in the culture medium, and co-localizes at the cell surface with virus structural proteins. Furthermore, both scanning electron micrograph (SEM) and transmission electron micrograph (TEM) show that MMTV accumulates on the surface of IFN??-stimulated cells.

Conclusions

Our data provide evidence that BST-2 restricts MMTV release from naturally infected cells and that BST-2 is an antiviral factor in vivo.     

Lack of association between glucocorticoid use and presence of the metabolic syndrome in patients with rheumatoid arthritis: a cross-sectional study

Lupus nephritis is a major contributor to morbidity and mortality in systemic lupus erythematosus, but little is known about the pathogenic processes that underlie the progressive decay in renal function. A common finding in lupus nephritis is thickening of glomerular basement membranes associated with immune complex deposition. It has been speculated that alterations in the synthesis or degradation of membrane components might contribute to such changes, and thereby to initiation and progression of nephritis through facilitation of immune complex deposition. Matrix metalloproteinases (MMPs) are enzymes that are intimately involved in the turnover of major glomerular basement membrane constituents, including collagen IV and laminins. Alterations in the expression and activity of MMPs have been described in a number of renal diseases, suggesting their relevance to the pathogenesis of various glomerulopathies. The same is true for their natural inhibitors, the tissue inhibitor of metalloproteinase family. Recent data from our group have identified an increase in proteolytic activity within the glomerulus coinciding with the development of proteinuria in the mouse model of systemic lupus erythematosus. (NXB × NZW)F₁ Here we review current understanding of MMP/tissue inhibitor of metalloproteinase function within the kidney, and discuss their possible involvement in the development and progression of lupus nephritis.     

赤红壤早稻田甲烷排放通量及其影响因素

用封闭箱法对广东省赤红壤早稻田CH4排放通量进行了观测。结果表明,CH4排放有明显的季节变化规律,3个排放高峰分别出现在水稻分蘖末期、孕穗抽穗期和乳熟期,平均通量为5.7mg.m-2.h-1。在测定期内,CH4排放与5和10cm土壤温度呈显著正相关,与土壤Eh呈显著负相关,与土壤pH值、水层深浅相关不明显。     

In situ fluorescent nick translation procedure for plant chromosomes

Pectinase and cellulase, which are used to macerate plant material, always show traces of DNase activities that result in DNA nicking. Moreover, the DNA polymerase I usually applied in the in situ nick translation techniques shows both 5' to 3' and 3' to 5' exonuclease activities. As a result, significant nonspecific labeling appears in control preparations that are not digested by a restriction endonuclease. Our procedure includes blocking nonspecific nick labeling before incubation with restriction enzymes (HpaII and HaeIII). This is achieved by incorporation of ddGTP into DNA by the Taq polymerase which lacks 3' to 5' exonuclease activity. This method gives satisfactory results because it eliminates nonspecific nick translation signals that are present after applying the methods described for animal material.     

A Dutch guideline for the treatment of scoliosis in neuromuscular disorders

Background

Children with neuromuscular disorders with a progressive muscle weakness such as Duchenne Muscular Dystrophy and Spinal Muscular Atrophy frequently develop a progressive scoliosis. A severe scoliosis compromises respiratory function and makes sitting more difficult. Spinal surgery is considered the primary treatment option for correcting severe scoliosis in neuromuscular disorders. Surgery in this population requires a multidisciplinary approach, careful planning, dedicated surgical procedures, and specialized after care.

Methods

The guideline is based on scientific evidence and expert opinions. A multidisciplinary working group representing experts from all relevant specialties performed the research. A literature search was conducted to collect scientific evidence in answer to specific questions posed by the working group. Literature was classified according to the level of evidence.

Results

For most aspects of the treatment scientific evidence is scarce and only low level cohort studies were found. Nevertheless, a high degree of consensus was reached about the management of patients with scoliosis in neuromuscular disorders. This was translated into a set of recommendations, which are now officially accepted as a general guideline in the Netherlands.

Conclusion

In order to optimize the treatment for scoliosis in neuromuscular disorders a Dutch guideline has been composed. This evidence-based, multidisciplinary guideline addresses conservative treatment, the preoperative, perioperative, and postoperative care of scoliosis in neuromuscular disorders.     

Antibodies to mutated citrullinated vimentin and disease activity score in early arthritis: a cohort study

Introduction  

The aim of our study was to investigate the association between arthritic disease activity and antibodies to mutated citrullinated vimentin (anti-MCV), because such a relation has been suggested.     

Singlet Oxygen Is the Major Reactive Oxygen Species Involved in Photooxidative Damage to Plants

Reactive oxygen species act as signaling molecules but can also directly provoke cellular damage by rapidly oxidizing cellular components, including lipids. We developed a high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry-based quantitative method that allowed us to discriminate between free radical (type I)- and singlet oxygen (¹O₂; type II)-mediated lipid peroxidation (LPO) signatures by using hydroxy fatty acids as specific reporters. Using this method, we observed that in nonphotosynthesizing Arabidopsis (Arabidopsis thaliana) tissues, nonenzymatic LPO was almost exclusively catalyzed by free radicals both under normal and oxidative stress conditions. However, in leaf tissues under optimal growth conditions, ¹O₂ was responsible for more than 80% of the nonenzymatic LPO. In Arabidopsis mutants favoring ¹O₂ production, photooxidative stress led to a dramatic increase of ¹O₂ (type II) LPO that preceded cell death. Furthermore, under all conditions and in mutants that favor the production of superoxide and hydrogen peroxide (two sources for type I LPO reactions), plant cell death was nevertheless always preceded by an increase in ¹O₂-dependent (type II) LPO. Thus, besides triggering a genetic cell death program, as demonstrated previously with the Arabidopsis fluorescent mutant, ¹O₂ plays a major destructive role during the execution of reactive oxygen species-induced cell death in leaf tissues.Plant leaves capture sun-derived light energy to drive CO₂ fixation during photosynthesis. During this process, leaves need to cope with photooxidative stress when the balance between energy absorption and consumption is disturbed. Excess excitation energy in the photosystems (PSI and PSII) leads to the inhibition of photosynthesis via the production of various reactive oxygen species (ROS) at different spatial levels of the cell (Apel and Hirt, 2004; Asada, 2006; Van Breusegem and Dat, 2006). Both exposure to high light intensities and decreased CO₂ availability direct linear electron transfer toward the reduction of molecular oxygen, generating superoxide radicals (O₂^−.) at PSI (the Mehler reaction). Superoxide dismutation generates hydrogen peroxide (H₂O₂), which is detoxified in the chloroplast by ascorbate peroxidases. As such, this so-called water-water cycle participates in the dissipation of excess energy (Asada, 2006). Decreased CO₂ availability affects the first step in CO₂ fixation by shifting the carboxylation of Rubisco by the Rubisco carboxylase-oxygenase enzyme toward oxygenation, a process called photorespiration. This leads, through the action of glycolate oxidase, to peroxisomal H₂O₂ production that is counteracted by catalases. Finally, when the intersystem electron carriers are overreduced, triplet excited P680 in the PSII reaction center as well as triplet chlorophylls in the light-harvesting antennae are produced, with the production of singlet oxygen (¹O₂) as a consequence (Krieger-Liszkay, 2005). In photosynthetic membranes, ¹O₂ is quenched by carotenoids and tocopherols. When antioxidant mechanisms are overwhelmed, increased cellular ROS levels trigger signal transduction events related to stress signaling and programmed cell death (Mittler et al., 2004; Van Breusegem and Dat, 2006). On the other hand, excessive ROS accumulation damages pigments, proteins, nucleic acids, and lipids (Halliwell and Gutteridge, 2007), thereby contributing to or executing cell death.Since under environmental stress conditions different ROS are produced simultaneously, a causal link between the accumulation of a specific ROS and its signaling or damaging effects has always been difficult to establish. In recent years, the production of various transgenic Arabidopsis (Arabidopsis thaliana) plants with compromised levels of specific antioxidant enzymes and the identification of the conditional fluorescent (flu) mutant provided important tools to assess the specific effects of O₂^−., H₂O₂, and ¹O₂ within a particular subcellular compartment (Dat et al., 2003; op den Camp et al., 2003; Pnueli et al., 2003; Rizhsky et al. 2003; Vandenabeele et al., 2004; Wagner et al., 2004; Queval et al., 2007). For example, with catalase-deficient [Cat(−)] plants, the signaling effects of increased photorespiratory H₂O₂ levels could be identified (Dat et al., 2003; Vandenabeele et al., 2004; Queval et al., 2007). Similarly, in the conditional flu mutant increased plastid ¹O₂ levels were shown to induce a genetic program leading to cell death (op den Camp et al., 2003; Wagner et al., 2004). Nevertheless, whereas careful monitoring of gene expression on the whole-genome level enables to pinpoint specific signaling capacities for diverse ROS (Mittler et al., 2004; Gadjev et al., 2006), it remained impossible to discriminate between the oxidative damaging effects on cellular components of different ROS.One consequence of ROS formation is lipid peroxidation (LPO; Halliwell and Gutteridge, 2007). Two nonenzymatic reaction types lead to specific patterns of oxidized membrane polyunsaturated fatty acids (PUFAs; Stratton and Liebler, 1997; Montillet et al., 2004; Mueller et al., 2006). Type I reactions are initiated by free radicals (FRs) having high redox potential, such as hydroxyl radicals (^.OH) or organic oxyl and peroxyl radicals, and type II reactions are the result of ¹O₂ action. Notably, O₂^−. and H₂O₂ are not sufficiently reactive to oxidize any PUFA. However, both ROS can be nonenzymatically converted to ^.OH through Fenton-type reactions in the presence of transition metal ions such as Fe²⁺ (Halliwell and Gutteridge, 2007). Both type I and type II reactions lead to the formation of respective oxygenated fatty acids. Here, we propose a novel and quantitative approach to distinguish between FR- and ¹O₂-mediated LPO in plants by quantifying type II oxidation-specific hydroxy fatty acids with HPLC-tandem mass spectrometry (MS/MS), allowing us to monitor the relative contribution of LPO caused by PSI-dependent O₂^−./H₂O₂, photorespiratory H₂O₂, and photosynthetic ¹O₂ during photooxidative stress and cell death. We demonstrate that nonenzymatic LPO in leaves is almost exclusively mediated by ¹O₂ and that photooxidative stress-dependent cell death involves ¹O₂ production in its final stage.     

Strain persistence of invasive Candida albicans in chronic hyperplastic candidosis that underwent malignant change

Objectives: The aim of this study was to assess persistence and tissue invasion of Candida albicans strains isolated from a 65 year‐old patient with chronic hyperplastic candidosis (CHC), that subsequently developed into squamous cell carcinoma (SCC). Materials and Methods: C. albicans (n=7) were recovered from the oral cavity of the patient over seven years. Confirmation of CHC and SCC in this patient was achieved by histopathological examination of incisional biopsy tissue. DNA fingerprinting was performed on the seven isolates from the CHC patient together with a further eight isolates from patients with normal oral mucosa (n=2), chronic atrophic candidosis (n=1), SCC (n=1) and CHC (n=4). Genotyping involved the use of inter‐repeat PCR using the eukaryotic repeat primer 1251. Characterisation of the tissue invasive abilities of the isolates was achieved by infecting a commercially available reconstituted human oral epithelium (RHE; SkinEthic, Nice, France). After 24 h. C. albicans tissue invasion was assessed by histopathological examination. Results: DNA fingerprinting demonstrated strain persistence of C. albicans in the CHC patient over a seven year period despite provision of systemic antifungal therapy. The strain of C. albicans isolated from this patient was categorised as a high invader within the RHE compared to other isolates. Conclusions: Candidal strain persistence was evident in a patient with CHC over seven years. This persistence may be due to incomplete eradication from the oral cavity following antifungal therapy or subsequent recolonisation from other body sites or separate exogenous sources. The demonstration of enhanced in vitro tissue invasion by this particular strain may, in part, explain the progression to carcinoma.