A TaqMan-based real-time PCR qualitative assay for the detection of three species of malaria parasitesPlasmodium falciparum, P. ovale, and P. vivax-was devised and evaluated using 122 whole-blood samples from patients who had traveled to areas where malaria is endemic and who presented with malaria-like symptoms and fever. The assay was compared to conventional microscopy and to an established nested-PCR assay. The specificity of the new assay was confirmed by sequencing the PCR products from all the positive samples and by the lack of cross-reactivity with Toxoplasma gondii and Leishmania infantum DNA. Real-time PCR assay showed a detection limit (analytical sensitivity) of 0.7, 4, and 1.5 parasites/l for P. falciparum, P. vivax, and P. ovale, respectively. Real-time PCR, like nested PCR, brought to light errors in the species identification by microscopic examination and revealed the presence of mixed infections (P. falciparum plus P. ovale). Real-time PCR can yield results within 2 h, does not require post-PCR processing, reduces sample handling, and minimizes the risks of contamination. The assay can therefore be easily implemented in routine diagnostic malaria tests. Future studies are warranted to investigate the clinical value of this technique.
Objectives To investigate thyroid function testing abnormalities in older persons and to explore the relationship between thyroid dysfunction and cognition. Design Cross-sectional study Setting Community-based Participants 1171 men and women aged 23-102 yrs Measurements Thyroid function was evaluated by measuring plasma concentrations of thyrotropin (TSH), free thyroxine (FT4), and free triiodothyronine (FT3). Cognition was evaluated by the Mini Mental State Examination (MMSE). Prevalence of overt and subclinical thyroid dysfunction was evaluated in different age groups (<65 versus ≥65 years). Age trends in TSH, FT4, and FT3 were examined in euthyroid participants. The cross-sectional association of thyroid dysfunction with MMSE score was evaluated adjusting for confounders. Results Both subclinical hypothyroidism and subclinical hyperthyroidism were more prevalent in older than in younger participants (Subclinical hypothyroidism, 0.4 % vs 3.5 % in younger vs older participants, respectively, P<.03 Subclinical hyperthyroidism, 1.9 % vs 7.8 % in younger vs older participants, respectively, P<.002). In euthyroid participants TSH and FT3 declined with age while FT4 increased. Old participants with subclinical hyperthyroidism had a lower MMSE score than euthyroid subjects (22.61 ± 6.88 vs 24.72 ± 4.52, P<.03). In adjusted analyses, participants with subclinical hyperthyroidism were significantly more likely to have cognitive dysfunction (HR: 2.26, P= .003). Conclusion Subtle age-related changes in FT3, FT4 and TSH occur in individuals who remain euthyroid. Subclinical hyperthyroidism is the most prevalent thyroid dysfunction in Italian older persons and is associated with cognitive impairment.
Detection of Plasmodium ovale by use of a nested PCR assay with a novel Plasmodium ovale primer set was superior to detection of Plasmodium ovale by real-time PCR assays. Nested PCR was also better at detecting P. malariae. The detection of P. ovale in many patients first admitted >2 months following their return to Italy indicated that P. ovale relapses are common.
A progressive, systemic, and low-grade proinflammatory status is one of the major characteristics of immunosenescence. Emerging data suggest a possible contribution of CMV, known to chronically infect a large proportion of humans, lifelong from newborns to centenarians. To test this hypothesis, we evaluated functional T cell responses to two CMV immunogenic proteins, pp65 and IE-1, in 65 chronically infected subjects aged 25–100 years. PBMC were stimulated with mixtures of peptides spanning the entire sequence of both proteins, and Ag specificity and magnitude of intracellular IFN-γ- and TNF-α-positive cells were then analyzed within both CD4+ and CD8+ T cells. Results indicate that pp65 and, to a lesser extent, IE-1 constitute major Ags against which aged people target functionally efficient T cell effector responses with massive production of Th1 cytokines and exhibition of CD107a degranulation marker. As a result, the production of IFN-γ induced in T cells by both Ags was seven to eight times greater in very old than in young subjects. The comparative analysis of pp65-specific responses in these very long-term carriers revealed a reciprocal relationship between CD4+ and CD8+ producing IFN-γ in the same individuals. These results indicate that CMV represents an important pathogen responsible for a strong immune activation in human aging. Such a remarkable burden of effector CD4+ and CD8+ T cells may be necessary to protect the elderly from CMV endogenous reactivation, but can turn detrimental by giving a substantial contribution to the proinflammatory status that accompanies the main age-related diseases.
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