Summary Background There are few data on the epidemiology and outcomes of influenza infection in recipients of solid-organ transplants. We aimed to establish the outcomes of pandemic influenza A H1N1 and factors leading to severe disease in a cohort of patients who had received transplants. Methods We did a multicentre cohort study of adults and children who had received organ transplants with microbiological confirmation of influenza A infection from April to December, 2009. Centres were identified through the American Society of Transplantation Influenza Collaborative Study Group. Demographics, clinical presentation, treatment, and outcomes were assessed. Severity of disease was measured by admission to hospital and intensive care units (ICUs). The data were analysed with descriptive statistics. Proportions were compared by use of χ2 tests. We used univariate analysis to identify factors leading to pneumonia, admission to hospital, and admission to an ICU. Multivariate analysis was done by use of a stepwise logistic regression model. We analysed deaths with Kaplan-Meier survival analysis. Findings We assessed 237 cases of medically attended influenza A H1N1 reported from 26 transplant centres during the study period. Transplant types included kidney, liver, heart, lung, and others. Both adults (154 patients; median age 47 years) and children (83; 9 years) were assessed. Median time from transplant was 3.6 years. 167 (71%) of 237 patients were admitted to hospital. Data on complications were available for 230 patients; 73 (32%) had pneumonia, 37 (16%) were admitted to ICUs, and ten (4%) died. Antiviral treatment was used in 223 (94%) patients (primarily oseltamivir monotherapy). Seven (8%) patients given antiviral drugs within 48 h of symptom onset were admitted to an ICU compared with 28 (22.4%) given antivirals later (p=0.007). Children who received transplants were less likely to present with pneumonia than adults, but rates of admission to hospital and ICU were similar. Interpretation Influenza A H1N1 caused substantial morbidity in recipients of solid-organ transplants during the 2009–10 pandemic. Starting antiviral therapy early is associated with clinical benefit as measured by need for ICU admission and mechanical ventilation.
Most Apicomplexan parasites, including the human pathogens Plasmodium, Toxoplasma, and Cryptosporidium, actively invade host cells and display gliding motility, both actions powered by parasite microfilaments. In Plasmodium sporozoites, thrombospondin-related anonymous protein (TRAP), a member of a group of Apicomplexan transmembrane proteins that have common adhesion domains, is necessary for gliding motility and infection of the vertebrate host. Here, we provide genetic evidence that TRAP is directly involved in a capping process that drives both sporozoite gliding and cell invasion. We also demonstrate that TRAP-related proteins in other Apicomplexa fulfill the same function and that their cytoplasmic tails interact with homologous partners in the respective parasite. Therefore, a mechanism of surface redistribution of TRAP-related proteins driving gliding locomotion and cell invasion is conserved among Apicomplexan parasites.
IMPORTANCE Congenital cytomegalovirus (cCMV) infection is a major cause of childhood deafness. Most cCMV infections are not diagnosed without newborn screening, resulting in missed opportunities for directed care.OBJECTIVE To estimate the cost-effectiveness of universal and targeted newborn cCMV screening programs compared with no cCMV screening. DESIGN, SETTING, AND PARTICIPANTS Models were constructed using rates and outcomes from prospective cohort studies of newborn cCMV screening in US postpartum care and early hearing programs. Costs of laboratory testing, treatment, and hearing loss were drawn from Medicaid data and published estimates. The benefits of cCMV screening were assumed to come from antiviral therapy for affected newborns to reduce hearing loss and from earlier identification of hearing loss with postnatal onset. Analyses were performed from July 2014 to March 2016.INTERVENTIONS Models compared universal or targeted cCMV screening of newborns with a failed hearing screen, with standard care for cCMV infection. MAIN OUTCOMES AND MEASURESThe incremental costs of identifying 1 cCMV infection, identifying 1 case of cCMV-related hearing loss, and preventing 1 cochlear implant; the incremental reduction in cases of severe to profound hearing loss; and the differences in costs per infant screened by universal or targeted strategies under different assumptions about the effectiveness of antiviral treatment.
Proteasomes degrade most of the proteins inside eukaryotic cells, including transcription factors and regulators of cell cycle progression.Here we show that nanomolar concentrations of lactacystin, a specific irreversible inhibitor of the 20S proteasome, inhibit development of the exoerythrocytic and erythrocytic stages of the malaria parasite. Although lactacystin-treated Plasmodium berghei sporozoites are still invasive, their development into exoerythrocytic forms (EEF) is inhibited in vitro and in vivo. Erythrocytic schizogony of P. falciparum in vitro is also profoundly inhibited when drug treatment of the synchronized parasites is prior, but not subsequent, to the initiation of DNA synthesis, suggesting that the inhibitory effect of lactacystin is cell cycle specific. Lactacystin reduces P. berghei parasitemia in rats, but the therapeutic index is very low. Along with other studies showing that lactacystin inhibits stage-specific transformation in Trypanosoma and Entamoeba spp., these findings highlight the potential of proteasome inhibitors as drugs for the treatment of diseases caused by protozoan parasites. MATERIALS AND METHODS Drugs.Lactacystin and lactacystin analogs were synthesized as previously described (4,13,22). 7-Ethyl lactacystin and des-7-methyl lactacystin were synthesized in the Harvard laboratory. All drugs, except clasto-lactacystin -lactone, were dissolved in H 2 O to 1 mM and stored at 4°C until use. clasto-lactacystin -lactone was solubilized in dimethyl sulfoxide to 10 mM and stored at Ϫ20°C until use. Lactacystin for injection into rats was dissolved in phosphate-buffered saline (PBS), pH 7.4, immediately before use.Assay for EEF development in vitro. This assay was performed as described previously (19) with a few modifications. Briefly, HepG2 cells (ATCC HB8065; American Type Culture Collection, Manassas, Va.) were plated in chamber slides (model 4808; Lab-tek, Naperville, Ill.) 48 h before each experiment. Plasmodium berghei sporozoites were dissected from mosquito salivary glands and resuspended in Dulbecco modified Eagle medium (Gibco BRL, Gaithersburg, Md.) supplemented with 10% fetal calf serum (HyClone Laboratories, Logan, Utah) and 20 mM HEPES (Sigma, St. Louis, Mo.). Approximately 50,000 sporozoites were added per well, and the parasites were allowed to adhere to and invade the HepG2 cells for 2 h. The wells were washed, and the cells were grown for an additional 2 days after which they were fixed with methanol. The EEF were then revealed with monoclonal antibody (MAb) 2E6 (34) followed by goat anti-mouse immunoglobulin (Ig) conjugated to horseradish peroxidase (Accurate Chemical Corp., Westbury, N.Y.) and 3,3Ј-diaminobenzidine (Sigma). The EEF in each well were counted microscopically with a 20ϫ light microscope objective.Microscopic assay for quantification of sporozoite invasion. This assay was conducted according to the method described by Renia et al. (27) with a few modifications. HepG2 cells were plated in chamber slides as described above. P. berghei sporozoites ...
Loop-mediated isothermal amplification (LAMP) is an isothermal nucleic acid amplification (iNAAT) technique known for its simplicity, sensitivity and speed. Its low-cost feature has resulted in its wide scale application, especially in low resource settings. The major disadvantage of LAMP is its heavy reliance on indirect detection methods like turbidity and non-specific dyes, which often leads to the detection of false positive results. In the present work, we have developed a direct detection approach, whereby a labelled loop probe quenched in its unbound state, fluoresces only when bound to its target (amplicon). Henceforth, referred to as Fluorescence of Loop Primer Upon Self Dequenching-LAMP (FLOS-LAMP), it allows for the sequence-specific detection of LAMP amplicons. The FLOS-LAMP concept was validated for rapid detection of the human pathogen, Varicella-zoster virus, from clinical samples. The FLOS-LAMP had a limit of detection of 500 copies of the target with a clinical sensitivity and specificity of 96.8% and 100%, respectively. The high level of specificity is a major advance and solves one of the main shortcomings of the LAMP technology, i.e. false positives. Self-quenching/de-quenching probes were further used with other LAMP primer sets and different fluorophores, thereby demonstrating its versatility and adaptability.
The sporozoite stage of the Plasmodium parasite is formed by budding from a multinucleate oocyst in the mosquito midgut. During their life, sporozoites must infect the salivary glands of the mosquito vector and the liver of the mammalian host; both events depend on the major sporozoite surface protein, the circumsporozoite protein (CS). We previously reported that Plasmodium berghei oocysts in which the CS gene is inactivated do not form sporozoites. Here, we analyzed the ultrastructure of P.berghei oocyst differentiation in the wild type, recombinants that do not produce or produce reduced amounts of CS, and corresponding complemented clones. The results indicate that CS is essential for establishing polarity in the oocyst. The amounts of CS protein correlate with the extent of development of the inner membranes and associated microtubules underneath the oocyst outer membrane, which normally demarcate focal budding sites. This is a first example of a protein controlling both morphogenesis and infectivity of a parasite stage.
Thrombospondin-related anonymous protein (TRAP), a candidate malaria vaccine antigen, is required for Plasmodium sporozoite gliding motility and cell invasion. For the first time, the ability of antibodies against TRAP to inhibit sporozoite infectivity in vivo is evaluated in detail. TRAP contains an A-domain, a wellcharacterized adhesive motif found in integrins. We modeled here a three-dimensional structure of the TRAP A-domain of Plasmodium yoelii and located regions surrounding the MIDAS (metal ion-dependent adhesion site), the presumed business end of the domain. Mice were immunized with constructs containing these Adomain regions but were not protected from sporozoite challenge. Furthermore, monoclonal and rabbit polyclonal antibodies against the A-domain, the conserved N terminus, and the repeat region of TRAP had no effect on the gliding motility or sporozoite infectivity to mice. TRAP is located in micronemes, secretory organelles of apicomplexan parasites. Accordingly, the antibodies tested here stained cytoplasmic TRAP brightly by immunofluorescence. However, very little TRAP could be detected on the surface of sporozoites. In contrast, a dramatic relocalization of TRAP onto the parasite surface occurred when sporozoites were treated with calcium ionophore. This likely mimics the release of TRAP from micronemes when a sporozoite contacts its target cell in vivo. Contact with hepatoma cells in culture also appeared to induce the release of TRAP onto the surface of sporozoites. If large amounts of TRAP are released in close proximity to its cellular receptor(s), effective competitive inhibition by antibodies may be difficult to achieve.
By capturing exposures and acquisition events, we found that the incidence and risk factors of infection vary by HHV type. HSV-1 infection, unlike other HHV infections, caused acute clinical illness in these infants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.