177 research outputs found

    Osedax borings in fossil marine bird bones

    Get PDF
    The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We provide the first evidence that Osedax was, and most likely still is, able to consume non-mammalian bones, namely bird bones. Borings resembling those produced by living Osedax were found in bones of early Oligocene marine flightless diving birds (family Plotopteridae). The species that produced these boreholes had a branching filiform root that grew to a length of at least 3Β mm, and lived in densities of up to 40 individuals per square centimeter. The inclusion of bird bones into the diet of Osedax has interesting implications for the recent suggestion of a Cretaceous origin of this worm because marine birds have existed continuously since the Cretaceous. Bird bones could have enabled this worm to survive times in the Earth’s history when large marine vertebrates other than fish were rare, specifically after the disappearance of large marine reptiles at the end-Cretaceous mass extinction event and before the rise of whales in the Eocene

    Cervical Cancer Screening among Patients Receiving ARVs in a Resource-Limited Environment

    Get PDF
    Significance Cervical cancer is the most common cancer worldwide with increased risk among women living with HIV in a resource limited environment. Hence the need to determine factors affecting awareness, prior uptake of cervical cancer screening and willingness to screen among patients receiving Antiretroviral (ARV) drugs. Data analysis The data was collected by administered questionnaires to patients presenting for monthly ARV refills in a HIV clinic in Dodoma, Tanzania. A total of 421 women in the clinic with an average monthly income of 39 (USD) were interviewed. A total of 306 (73%) were aware of cervical cancer. Among those who were aware, 84 % (257) did not recall been screened for cervical cancer. A total of 231 (90%) expressed willingness to be screened among patients who have never screened for cervical cancer. The average years since HIV infection for the subjects was 5.4 years; average age was 44. A logistic regression model was used to examine factors associated with awareness of cervical cancer, prior uptake of screening and willingness to be screened. Urban dwellers were found to have higher odds of awareness than rural dwellers (OR: 3.68 95% CI: 2.12-6.38). Prior uptake of screening was found higher among urban vs. rural dwellers, OR: 3.43, 95% CI: 1.02-11.51. The willingness to be screened decreased with age (OR: 0.93, 95% CI: 0.88-0.97). Conclusion This study have indicated the problem of access among rural dwellers to cervical cancer screening. Willingness to screen among younger patients could be due to increased awareness of the disease among younger patients than older patients. However, the older and rural patients are at higher risk of cervical cancer and should be targeted for primary prevention. Category Advocacy and Health Policyhttps://digitalcommons.unmc.edu/coph_pres/1007/thumbnail.jp

    Cytosolic Fc receptor TRIM21 inhibits seeded tau aggregation

    Get PDF
    Alzheimer's disease (AD) and other neurodegenerative disorders are associated with the cytoplasmic aggregation of microtubule-associated protein tau. Recent evidence supports transcellular transfer of tau misfolding (seeding) as the mechanism of spread within an affected brain, a process reminiscent of viral infection. However, whereas microbial pathogens can be recognized as nonself by immune receptors, misfolded protein assemblies evade detection, as they are host-derived. Here, we show that when misfolded tau assemblies enter the cell, they can be detected and neutralized via a danger response mediated by tau-associated antibodies and the cytosolic Fc receptor tripartite motif protein 21 (TRIM21). We developed fluorescent, morphology-based seeding assays that allow the formation of pathological tau aggregates to be measured in situ within 24 h in the presence of picomolar concentrations of tau seeds. We found that anti-tau antibodies accompany tau seeds into the cell, where they recruit TRIM21 shortly after entry. After binding, TRIM21 neutralizes tau seeds through the activity of the proteasome and the AAA ATPase p97/VCP in a similar manner to infectious viruses. These results establish that intracellular antiviral immunity can be redirected against host-origin endopathogens involved in neurodegeneration

    Genetic Markers of IgG Influence The Outcome of Infection with Hepatitis C Virus

    Get PDF
    We examined the role that immunoglobulin GM and KM allotypesβ€”genetic markers of Ξ³ and ΞΊ chains, respectivelyβ€”play in the outcome of hepatitis C virus (HCV) infection in white Americans. A total of 119 persons who had cleared HCV and 111 with persistent HCV infection were genotyped for the presence of several GM and KM determinants. Persistent HCV infection was more than three times as likely (odds ratio, 3.50; P = .01) in subjects who were carriers of the GM3 allele than in those who were noncarriers. These results show that particular GM alleles may be important determinants of the outcome of HCV infection

    Hemophilic Siblings With Chronic Hepatitis C: Familial Aggregation of Spontaneous and Treatment-Related Viral Clearance

    Get PDF
    Hemophilic siblings provide a unique population to explore the natural history of chronic hepatitis C

    Evidence against a role for jaagsiekte sheep retrovirus in human lung cancer

    Get PDF
    Background: Jaagsiekte sheep retrovirus (JSRV) causes a contagious lung cancer in sheep and goats that can be transmitted by aerosols produced by infected animals. Virus entry into cells is initiated by binding of the viral envelope (Env) protein to a specific cell-surface receptor, Hyal2. Unlike almost all other retroviruses, the JSRV Env protein is also a potent oncoprotein and is responsible for lung cancer in animals. Of concern, Hyal2 is a functional receptor for JSRV in humans. Results: We show here that JSRV is fully capable of infecting human cells, as measured by its reverse transcription and persistence in the DNA of cultured human cells. Several studies have indicated a role for JSRV in human lung cancer while other studies dispute these results. To further investigate the role of JSRV in human lung cancer, we used highly-specific mouse monoclonal antibodies and a rabbit polyclonal antiserum against JSRV Env to test for JSRV expression in human lung cancer. JSRV Env expression was undetectable in lung cancers from 128 human subjects, including 73 cases of bronchioalveolar carcinoma (BAC; currently reclassified as lung invasive adenocarcinoma with a predominant lepidic component), a lung cancer with histology similar to that found in JSRV-infected sheep. The BAC samples included 8 JSRV DNA-positive samples from subjects residing in Sardinia, Italy, where sheep farming is prevalent and JSRV is present. We also tested for neutralizing antibodies in sera from 138 Peruvians living in an area where sheep farming is prevalent and JSRV is present, 24 of whom were directly exposed to sheep, and found none. Conclusions: We conclude that while JSRV can infect human cells, JSRV plays little if any role in human lung cancer

    Role of Exonic Variation in Chemokine Receptor Genes on AIDS: CCRL2 F167Y Association with Pneumocystis Pneumonia

    Get PDF
    Chromosome 3p21–22 harbors two clusters of chemokine receptor genes, several of which serve as major or minor coreceptors of HIV-1. Although the genetic association of CCR5 andCCR2 variants with HIV-1 pathogenesis is well known, the role of variation in other nearby chemokine receptor genes remain unresolved. We genotyped exonic single nucleotide polymorphisms (SNPs) in chemokine receptor genes: CCR3, CCRL2, and CXCR6 (at 3p21) and CCR8 and CX3CR1 (at 3p22), the majority of which were non-synonymous. The individual SNPs were tested for their effects on disease progression and outcomes in five treatment-naΓ―ve HIV-1/AIDS natural history cohorts. In addition to the known CCR5 and CCR2associations, significant associations were identified for CCR3, CCR8, and CCRL2 on progression to AIDS. A multivariate survival analysis pointed to a previously undetected association of a non-conservative amino acid change F167Y in CCRL2 with AIDS progression: 167F is associated with accelerated progression to AIDS (RHβ€Š=β€Š1.90, Pβ€Š=β€Š0.002, corrected). Further analysis indicated that CCRL2-167F was specifically associated with more rapid development of pneumocystis pneumonia (PCP) (RHβ€Š=β€Š2.84, 95% CI 1.28–6.31) among four major AIDS–defining conditions. Considering the newly defined role of CCRL2 in lung dendritic cell trafficking, this atypical chemokine receptor may affect PCP through immune regulation and inducing inflammation

    Genetic Variants in Nuclear-Encoded Mitochondrial Genes Influence AIDS Progression

    Get PDF
    Background: The human mitochondrial genome includes only 13 coding genes while nuclear-encoded genes account for 99% of proteins responsible for mitochondrial morphology, redox regulation, and energetics. Mitochondrial pathogenesis occurs in HIV patients and genetically, mitochondrial DNA haplogroups with presumed functional differences have been associated with differential AIDS progression. Methodology/Principal Findings: Here we explore whether single nucleotide polymorphisms (SNPs) within 904 of the estimated 1,500 genes that specify nuclear-encoded mitochondrial proteins (NEMPs) influence AIDS progression among HIV-1 infected patients. We examined NEMPs for association with the rate of AIDS progression using genotypes generated by an Affymetrix 6.0 genotyping array of 1,455 European American patients from five US AIDS cohorts. Successfully genotyped SNPs gave 50% or better haplotype coverage for 679 of known NEMP genes. With a Bonferroni adjustment for the number of genes and tests examined, multiple SNPs within two NEMP genes showed significant association with AIDS progression: acyl-CoA synthetase medium-chain family member 4 (ACSM4) on chromosome 12 and peroxisomal D3,D2-enoyl- CoA isomerase (PECI) on chromosome 6. Conclusions: Our previous studies on mitochondrial DNA showed that European haplogroups with presumed functional differences were associated with AIDS progression and HAART mediated adverse events. The modest influences of nuclearencoded mitochondrial genes found in the current study add support to the idea that mitochondrial function plays a role in AIDS pathogenesis
    • …
    corecore