Thiol dependent NF-κB suppression and inhibition of T-cell mediated adaptive immune responses by a naturally occurring steroidal lactone Withaferin A.

Withaferin A (WA), a steroidal lactone isolated from ayurvedic medicinal plant Withania somnifera, was shown to inhibit tumor growth by inducing oxidative stress and suppressing NF-κB pathway. However, its effect on T-cell mediated adaptive immune responses and the underlying mechanism has not been investigated. Since both T-cell responses and NF-κB pathway are known to be redox sensitive, the present study was undertaken to elucidate the effect of WA on adaptive immune responses in vitro and in vivo. WA inhibited mitogen induced T-cell and B-cell proliferation in vitro without inducing any cell death. It inhibited upregulation of T-cell (CD25, CD69, CD71 and CD54) and B-cell (CD80, CD86 and MHC-II) activation markers and secretion of Th1 and Th2 cytokines. WA induced oxidative stress by increasing the basal ROS levels and the immunosuppressive effects of WA were abrogated only by thiol anti-oxidants. The redox modulatory effects of WA in T-cells were attributed to its ability to directly interact with free thiols. WA inhibited NF-κB nuclear translocation in lymphocytes and prevented the direct binding of nuclear NF-κB to its consensus sequence. MALDI-TOF analysis using a synthetic NF-κB-p50 peptide containing Cys-62 residue suggested that WA can modify the cysteine residue of NF-κB. The pharmacokinetic studies for WA were also carried out and in vivo efficacy of WA was studied using mouse model of Graft-versus-host disease. In conclusion, WA is a potent inhibitor of T-cell responses and acts via a novel thiol dependent mechanism and inhibition of NF-κB pathway.

Extreme harmonic generation in electrically driven spin resonance.

We report the observation of multiple harmonic generation in electric dipole spin resonance in an InAs nanowire double quantum dot. The harmonics display a remarkable detuning dependence: near the interdot charge transition as many as eight harmonics are observed, while at large detunings we only observe the fundamental spin resonance condition. The detuning dependence indicates that the observed harmonics may be due to Landau-Zener transition dynamics at anticrossings in the energy level spectrum.

Exploration of 2, 4-diaminopyrimidine and 2, 4-diamino-s-triazine derivatives as potential antifilarial agents.

In view of the mandate from the World Health Organization (WHO) for developing novel drug candidates against human lymphatic filariasis, dihydrofolate reductase (DHFR) inhibitors are explored as potential antifilarial agents. The in vitro biological evaluation of an in-house library of 12 diverse antifolate compounds with 2,4-diaminopyrimidine and 2,4-diamino-s-triazine structural features against Brugia malayi is reported. To confirm the DHFR inhibitory potential of these compounds, reversal studies using folic acid and folinic acid were undertaken. Inhibition of DHFR can induce apoptosis; in this light, preliminary evidence of apoptosis by test compounds was detected using ethidium bromide-acridine orange staining and the poly(adenosine diphosphate-ribose) polymerase (PARP) inhibition assay. Among the evaluated compounds, 3 showed significant activity against both microfilariae and adult worms. The effects of 2 of these compounds were mostly reversed by folic acid, validating DHFR inhibitory activity. Partial reversal of the effect of 2 compounds by folinic acid and non-reversal of the effect of the third compound both by folic and folinic acids are discussed. This study opens new avenues for the discovery of lead molecules by exploiting the folate pathway against one of the major neglected tropical diseases, filariasis.

[Notes on rapid diagnostic tests for chronic Chagas disease]. / Notes sur les tests de diagnostic rapide pour la maladie de Chagas en phase chronique.

A rapid diagnostic test (RDT) is a test that can quickly determine (from minutes up to 2 h) a diagnosis. It is a simple, quick, and inexpensive technique that does not require complex equipment or specialized staff. For this reason, such tests have been proposed for the diagnosis of Chagas Disease (CD), which affects populations difficult to reach, or migrants in nonendemic areas, where there is a low prevalence of the disease. With these notes we take into consideration one of the best RDTs for CD currently available on the market as an example and make some comments on its use in the field on the base of the current evidences.

Seroprevalence of five neglected parasitic diseases among immigrants accessing five infectious and tropical diseases units in Italy: a cross-sectional study.

OBJECTIVE: This multicentre cross-sectional study aims to estimate the prevalence of five neglected tropical diseases (Chagas disease, filariasis, schistosomiasis, strongyloidiasis and toxocariasis) among immigrants accessing health care facilities in five Italian cities (Bologna, Brescia, Florence, Rome, Verona). METHODS: Individuals underwent a different set of serological tests, according to country of origin and presence of eosinophilia. Seropositive patients were treated and further followed up. RESULTS: A total of 930 adult immigrants were enrolled: 477 men (51.3%), 445 women (47.9%), eight transgender (0.8%); median age was 37.81 years (range 18-80 years). Most of them had come from the African continent (405/930, 43.5%), the rest from East Europe, South America and Asia, and 9.6% (89/930) were diagnosed with at least one of the infections under study. Seroprevalence of each specific infection varied from 3.9% (7/180) for Chagas disease to 9.7% (11/113) for toxocariasis. Seropositive people were more likely to be 35-40 years old and male, and to come from South East Asia, sub-Saharan Africa or South America. CONCLUSIONS: The results of our study confirm that neglected tropical diseases represent a substantial health problem among immigrants and highlight the need to address this emerging public health issue.

[Evaluation of the new ImmunoCard STAT!® CGE test for the diagnosis of Amebiasis]. / Évaluation d'un nouveau test ImmunoCard STAT!® CGE pour le diagnostic de l'amibiase.

For many years, microscopic examination of stool samples has been considered to be the "gold standard" for diagnosis of intestinal parasites although the Polymerase Chain Reaction (PCR) analysis is increasingly utilized due to its high accuracy. Recently, PCR has been approved by the World Health Organization as the current method of choice for the diagnosis of Entamoeba histolytica infection. In this study we evaluated a novel immunochromatographic antigen detection rapid test, ImmunoCardSTAT CGE (Meridian Bioscence, Milan, Italy), which has been proposed for the diagnosis of infections caused by Cryptosporidium parvum-Giardia intestinalis-Entamoeba histolytica. There is another rapid test with a similar name, the ImmunoCard STAT! Crypto/Giardia, but it is just for Cryptosporidium and Giardia. We aimed to compare E. histolytica results obtained from the rapid test with those of a rt-PCR for the detection of E. histolytica / E. dispar DNA. The new ImmunoCard rapid antigen detection test exhibited 88% sensitivity and 92% specificity (if assessed on rt-PCR negative samples) but showed a high proportion of cross-reaction between the pathogenic E. histolytica and the non pathogenic E. dispar.