262 research outputs found

    Ischemic stroke as a complication of cryptococcal meningitis and immune reconstitution inflammatory syndrome: a case report.

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    BACKGROUND: Cryptococcal meningitis remains the leading cause of adult meningitis in Sub-Saharan Africa. Immune Reconstitution Inflammatory Syndrome (IRIS) following anti-retroviral therapy (ART) initiation is an important complication. Here we report the first documented case of a IRIS reaction presenting as an ischemic stroke. CASE PRESENTATION: A 38 year old newly diagnosed HIV-infected, ART naive Malawian male presented to a tertiary referral hospital in Blantyre, Malawi with a 2 week history of headache. A diagnosis of cryptococcal meningitis was made and the patient was started on 1200 mg fluconazole once daily and flucytosine 25 mg/kg four times daily as part of the Advancing Cryptococcal Treatment for Africa (ACTA) clinical trial. There was an initial clinical and microbiological response to anti-fungal treatment and anti-retroviral therapy was started at week 4. The patient re-presented 16 days later with recurrence of headache, fever, and a sudden onset of left sided weakness in the context of rapid immune reconstitution; peripheral CD4 count had increased from a baseline of 29 cells/μl to 198 cells/μl. Recurrence of cryptococcal meningitis was excluded through CSF examination and fungal culture. Magnetic Resonance Imaging (MRI) of the brain demonstrated multi-focal DWI (diffusion weighted imaging) positive lesions consistent with an ischemic stroke. Given the temporal relationship to ART initiation, these MRI findings in the context of sterile CSF with raised CSF protein and a rapid immune reconstitution, following an earlier favorable response to treatment is most consistent with a paradoxical Immune Reconstitution Inflammatory Syndrome. CONCLUSIONS: Stroke is an increasing cause of morbidity and mortality amongst HIV infected persons. Ischemic stroke is a recognized complication of cryptococcal meningitis in the acute phase and is thought to be mediated by an infectious vasculitis. This is the first time an ischemic stroke has been described as part of a paradoxical IRIS reaction. This report adds to the spectrum of clinical IRIS presentations recognized and highlights to clinicians the potential complications encountered at ART initiation in severely immunocompromised patients

    Pathophysiological classification of chronic rhinosinusitis

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    BACKGROUND: Recent consensus statements demonstrate the breadth of the chronic rhinosinusitis (CRS) differential diagnosis. However, the classification and mechanisms of different CRS phenotypes remains problematic. METHOD: Statistical patterns of subjective and objective findings were assessed by retrospective chart review. RESULTS: CRS patients were readily divided into those with (50/99) and without (49/99) polyposis. Aspirin sensitivity was limited to 17/50 polyp subjects. They had peripheral blood eosinophilia and small airways obstruction. Allergy skin tests were positive in 71% of the remaining polyp subjects. IgE was<10 IU/ml in 8/38 polyp and 20/45 nonpolyp subjects (p = 0.015, Fisher's Exact test). CT scans of the CRS without polyp group showed sinus mucosal thickening (probable glandular hypertrophy) in 28/49, and nasal osteomeatal disease in 21/49. Immunoglobulin isotype deficiencies were more prevalent in nonpolyp than polyp subjects (p < 0.05). CONCLUSION: CRS subjects were retrospectively classified in to 4 categories using the algorithm of (1) polyp vs. nonpolyp disease, (2) aspirin sensitivity in polyposis, and (3) sinus mucosal thickening vs. nasal osteomeatal disease (CT scan extent of disease) for nonpolypoid subjects. We propose that the pathogenic mechanisms responsible for polyposis, aspirin sensitivity, humoral immunodeficiency, glandular hypertrophy, eosinophilia and atopy are primary mechanisms underlying these CRS phenotypes. The influence of microbial disease and other factors remain to be examined in this framework. We predict that future clinical studies and treatment decisions will be more logical when these interactive disease mechanisms are used to stratify CRS patients

    Oxidation of DJ-1 Induced by 6-Hydroxydopamine Decreasing Intracellular Glutathione

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    DJ-1, the causative gene of a familial form of Parkinson's disease (PD), has been reported to undergo preferential oxidation of the cysteine residue at position 106 (Cys-106) under oxidative stress; however, details of the molecular mechanisms are not well known. In the present study, mechanisms of DJ-1 oxidation induced by 6-hydroxydopamine (6-OHDA) were investigated by using SH-SY5Y cells. The treatment of these cells with 6-OHDA caused an obvious acidic spot sift of DJ-1 due to its oxidation. However, when catalase, which is an hydrogen peroxide (H2O2)-removing enzyme, was added during the treatment, it failed to prevent the oxidation induced by 6-OHDA, suggesting that electrophilic p-quinone formed from 6-OHDA, but not H2O2, was responsible for the DJ-1 oxidation. Benzoquinone, another electrophilic p-quinone, also induced DJ-1 oxidation. The intracellular glutathione (GSH) levels were significantly decreased by 6-OHDA, irrespective of the presence or absence of catalase. The inhibition of GSH synthesis by buthionine sulfoximine resulted in a decrease in GSH levels and enhancement of DJ-1 oxidation. The pretreatment of cells with N-acetyl-cysteine prevented the loss of intracellular GSH and subsequently DJ-1 oxidation induced by 6-OHDA. Collectively, these results suggest that electrophilic p-quinone formed from 6-OHDA induces DJ-1 oxidation by decreasing intracellular GSH

    Discordant American College of Physicians and international rheumatology guidelines for gout management: consensus statement of the Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN).

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    In November 2016, the American College of Physicians (ACP) published a clinical practice guideline on the management of acute and recurrent gout. This guideline differs substantially from the latest guidelines generated by the American College of Rheumatology (ACR), European League Against Rheumatism (EULAR) and 3e (Evidence, Expertise, Exchange) Initiative, despite reviewing largely the same body of evidence. The Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN) convened an expert panel to review the methodology and conclusions of these four sets of guidelines and examine possible reasons for discordance between them. The G-CAN position, presented here, is that the fundamental pathophysiological knowledge underlying gout care, and evidence from clinical experience and clinical trials, supports a treat-to-target approach for gout aimed at lowering serum urate levels to below the saturation threshold at which monosodium urate crystals form. This practice, which is truly evidence-based and promotes the steady reduction in tissue urate crystal deposits, is promoted by the ACR, EULAR and 3e Initiative recommendations. By contrast, the ACP does not provide a clear recommendation for urate-lowering therapy (ULT) for patients with frequent, recurrent flares or those with tophi, nor does it recommend monitoring serum urate levels of patients prescribed ULT. Results from emerging clinical trials that have gout symptoms as the primary end point are expected to resolve this debate for all clinicians in the near term future

    Kinetic Analysis of Substrate Utilization by Native and TNAP-, NPP1-, or PHOSPHO1-Deficient Matrix Vesicles

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    During the process of endochondral bone formation, chondrocytes and osteoblasts mineralize their extracellular matrix by promoting the formation of hydroxyapatite seed crystals in the sheltered interior of membrane-limited matrix vesicles (MVs). Here, we have studied phosphosubstrate catalysis by osteoblast-derived MVs at physiologic pH, analyzing the hydrolysis of ATP, ADP, and PPi by isolated wild-type (WT) as well as TNAP-, NPP1- and PHOSPHO1-deficient MVs. Comparison of the catalytic efficiencies identified ATP as the main substrate hydrolyzed by WT MVs. The lack of TNAP had the most pronounced effect on the hydrolysis of all physiologic substrates. The lack of PHOSPHO1 affected ATP hydrolysis via a secondary reduction in the levels of TNAP in PHOSPHO1-deficient MVs. The lack of NPP1 did not significantly affect the kinetic parameters of hydrolysis when compared with WT MVs for any of the substrates. We conclude that TNAP is the enzyme that hydrolyzes both ATP and PPi in the MV compartment. NPP1 does not have a major role in PPi generation from ATP at the level of MVs, in contrast to its accepted role on the surface of the osteoblasts and chondrocytes, but rather acts as a phosphatase in the absence of TNAP. © 2010 American Society for Bone and Mineral Research

    Sequence Variations of Latent Membrane Protein 2A in Epstein-Barr Virus-Associated Gastric Carcinomas from Guangzhou, Southern China

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    Latent membrane protein 2A (LMP2A), expressed in most Epstein-Barr virus (EBV)-associated malignancies, has been demonstrated to be responsible for the maintenance of latent infection and epithelial cell transformation. Besides, it could also act as the target for a CTL-based therapy for EBV-associated malignancies. In the present study, sequence variations of LMP2A in EBV-associated gastric carcinoma (EBVaGC) and healthy EBV carriers from Guangzhou, southern China, where nasopharyngeal carcinoma (NPC) is endemic, were investigated. Widespread sequence variations in the LMP2A gene were found, with no sequence identical to the B95.8 prototype. No consistent mutation was detected in all isolates. The immunoreceptor tyrosine-based activation motif (ITAM) and PY motifs in the amino terminus of LMP2A were strictly conserved, suggesting their important roles in virus infection; while 8 of the 17 identified CTL epitopes in the transmembrane region of LMP2A were affected by at least one point mutation, which may implicate that the effect of LMP2A polymorphisms should be considered when LMP2A-targeted immunotherapy is conducted. The polymorphisms of LMP2A in EBVaGC in gastric remnant carcinoma (GRC) were for the first time investigated in the world. The LMP2A sequence variations in EBVaGC in GRC were somewhat different from those in EBVaGC in conventional gastric carcinoma. The sequence variations of LMP2A in EBVaGC were similar to those in throat washing of healthy EBV carriers, indicating that these variations are due to geographic-associated polymorphisms rather than EBVaGC-associated mutations. This, to our best knowledge, is the first detailed investigation of LMP2A polymorphisms in EBVaGC in Guangzhou, southern China, where NPC is endemic

    H. pylori-infection and antibody immune response in a rural Tanzanian population

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    BACKGROUND: Helicobacter pylori (H. pylori) infection is ubiquitous in sub-Saharan Africa, but paradoxically gastric cancer is rare. METHODS: Sera collected during a household-based survey in rural Tanzania in 1985 were tested for anti-H. pylori IgG and IgG subclass antibodies by enzyme immunoassay. Odds ratios (OR) and confidence intervals (CI) of association of seropositivity with demographic variables were computed by logistic regression models. RESULTS: Of 788 participants, 513 were aged ≤17 years. H. pylori seropositivity increased from 76% at 0–4 years to 99% by ≥18 years of age. Seropositivity was associated with age (OR 11.5, 95% CI 4.2–31.4 for 10–17 vs. 0–4 years), higher birth-order (11.1; 3.6–34.1 for ≥3(rd )vs. 1(st )born), and having a seropositive next-older sibling (2.7; 0.9–8.3). Median values of IgG subclass were 7.2 for IgG1 and 2.0 for IgG2. The median IgG1/IgG2 ratio was 3.1 (IQR: 1.7–5.6), consistent with a Th2-dominant immune profile. Th2-dominant response was more frequent in children than adults (OR 2.4, 95% CI 1.3–4.4). CONCLUSION: H. pylori seropositivity was highly prevalent in Tanzania and the immunological response was Th2-dominant. Th2-dominant immune response, possibly caused by concurrent bacterial or parasitic infections, could explain, in part, the lower risk of H. pylori-associated gastric cancer in Africa

    Incorporation of lipid nanosystems containing omega‑3 fatty acids and resveratrol in textile substrates for wound healing and anti‑inflammatory applications

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    In the present work, lipid nanosystems containing omega-3 fatty acid (nanostructured lipid carriers, NLCs) or omega-3 fatty acid and resveratrol (liposomes) were developed to improve cotton textile substrates as dressings with anti-inflammatory properties for wound healing applications. Lipid nanosystems were incorporated into woven, non-woven and knitted cotton substrates by exhaustion and impregnation. Based on physical–chemical characterization of the textile substrates, the textile structure and type of lipid nanosystems dictated the adsorption efficiency. In the case of NLCs, the woven substrate functionalized by exhaustion had a higher omega-3 release being the most promising for wound dressing application. Whereas for liposomes, the most adequate textile was the cationized knitted fabric functionalized by impregnation, that showed a more prolonged release profile of resveratrol.This work is financed by Project UID/CTM/00264/2019 of 2C2T - Centro de Ciencia e Tecnologia Textil, funded by National Founds through FCT/MCTES. The authors also acknowledge the Portuguese Foundation for Science and Technology (FCT) for financial support in the framework of the Strategic Funding UID/Multi/04546/2013 and UID/FIS/04650/2019 in the ambit of the project POCI-01-0145-FEDER-032651, co-financed by the European Regional Development Fund (ERDF), through COMPETE 2020, under Portugal 2020

    Visualizing early splenic memory CD8+ T cells reactivation against intracellular bacteria in the mouse

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    International audienceMemory CD8(+) T cells represent an important effector arm of the immune response in maintaining long-lived protective immunity against viruses and some intracellular bacteria such as Listeria monocytogenes (L.m). Memory CD8(+) T cells are endowed with enhanced antimicrobial effector functions that perfectly tail them to rapidly eradicate invading pathogens. It is largely accepted that these functions are sufficient to explain how memory CD8(+) T cells can mediate rapid protection. However, it is important to point out that such improved functional features would be useless if memory cells were unable to rapidly find the pathogen loaded/infected cells within the infected organ. Growing evidences suggest that the anatomy of secondary lymphoid organs (SLOs) fosters the cellular interactions required to initiate naive adaptive immune responses. However, very little is known on how the SLOs structures regulate memory immune responses. Using Listeria monocytogenes (L.m) as a murine infection model and imaging techniques, we have investigated if and how the architecture of the spleen plays a role in the reactivation of memory CD8(+) T cells and the subsequent control of L.m growth. We observed that in the mouse, memory CD8(+) T cells start to control L.m burden 6 hours after the challenge infection. At this very early time point, L.m-specific and non-specific memory CD8(+) T cells localize in the splenic red pulp and form clusters around L.m infected cells while naïve CD8(+) T cells remain in the white pulp. Within these clusters that only last few hours, memory CD8(+) T produce inflammatory cytokines such as IFN-gamma and CCL3 nearby infected myeloid cells known to be crucial for L.m killing. Altogether, we describe how memory CD8(+) T cells trafficking properties and the splenic micro-anatomy conjugate to create a spatio-temporal window during which memory CD8(+) T cells provide a local response by secreting effector molecules around infected cells

    Systematic characterization of deubiquitylating enzymes for roles in maintaining genome integrity.

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    DNA double-strand breaks (DSBs) are perhaps the most toxic of all DNA lesions, with defects in the DNA-damage response to DSBs being associated with various human diseases. Although it is known that DSB repair pathways are tightly regulated by ubiquitylation, we do not yet have a comprehensive understanding of how deubiquitylating enzymes (DUBs) function in DSB responses. Here, by carrying out a multidimensional screening strategy for human DUBs, we identify several with hitherto unknown links to DSB repair, the G2/M DNA-damage checkpoint and genome-integrity maintenance. Phylogenetic analyses reveal functional clustering within certain DUB subgroups, suggesting evolutionally conserved functions and/or related modes of action. Furthermore, we establish that the DUB UCHL5 regulates DSB resection and repair by homologous recombination through protecting its interactor, NFRKB, from degradation. Collectively, our findings extend the list of DUBs promoting the maintenance of genome integrity, and highlight their potential as therapeutic targets for cancer.This is the author's accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/ncb302
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