Magnetoencephalography reveals differences in brain activations for fast and slow responses to simple multiplications

Despite decades of studies, it is still an open question on how and where simple multiplications are solved by the brain. This fragmented picture is mostly related to the different tasks employed. While in neuropsychological studies patients are asked to perform and report simple oral calculations, neuroimaging and neurophysiological studies often use verification tasks, in which the result is shown, and the participant must verify the correctness. This MEG study aims to unify the sources of evidence, investigating how brain activation unfolds in time using a single-digit multiplication production task. We compared the participants' brain activity-focusing on the parietal lobes-based on response efficiency, dividing their responses in fast and slow. Results showed higher activation for fast, as compared to slow, responses in the left angular gyrus starting after the first operand, and in the right supramarginal gyrus only after the second operand. A whole-brain analysis showed that fast responses had higher activation in the right dorsolateral prefrontal cortex. We show a timing difference of both hemispheres during simple multiplications. Results suggest that while the left parietal lobe may allow an initial retrieval of several possible solutions, the right one may be engaged later, helping to identify the solution based on magnitude checking.

Clinical outcomes of Clostridium difficile infection according to strain type. A prospective study in medical wards

OBJECTIVES

To describe clinical characteristics and outcome of Clostridium difficile infection (CDI) patients in Internal Medicine, to identify ribotypes (RTs); to evaluate the association between RT and patient clinical characteristics and report outcome.

METHODS

One year prospective cohort study. Clinical data, Barthel Index (BI) and outcomes were collected for all inpatients suffering from CDI (n = 148) in hospital wards in Northern Italy. 84 fecal samples were analysed for molecular typing.

RESULTS

12 RTs were identified, predominantly RT018 (42.9%, n = 36/84) and RT356/607 (40.5%, n = 34/84). Patients with dementia were more frequent among those infected by RT018 [55.6% (n = 20/36) vs. 32.4% (n = 11/34), p = 0.05]. The median BI score of patients with RT018 was lower than BI score of patients with RT356/607 [10 (IQR 0-32) vs. 15 (IQR 5-50), p = 0.06]. RT018 infection was associated to higher levels of C-reactive protein [7.2 mg/dl (IQR 4.1-14.7) vs. 4.0 mg/dl (IQR 2.2-6.8), p = 0.01] and white blood cells ≥15,000/dl [33.3% (n = 12/36) vs. 14.7% (n = 5/34) of patients, p = 0.07]. Higher mortality was noted among RT018 infected patients. We found a continuous mortality increase according to the ATLAS score.

CONCLUSIONS

Our results confirm that RT018 and RT356/607 are the two major RTs causing CDI in older patients with a high degree of disability in Northern Italy and RT018 is associated with more serious outcomes.

Analysis of nosocomial acquired Clostridium difficile infection in an Italian research and teaching hospital

BACKGROUND

Clostridium difficile (Cd) infection is a nosocomial plague which is correlated with several clinical and medical factors such as antibiotics intake. It is known that prevention is possible through infection control measures both clinical and epidemiological.

METHODS

We examined the data from a study about Cd infection in four internal medicine wards in a teaching and research hospital in the north part of Italy in a two years period. The wards are only slightly different in size, plan, structures, nursing staff and patient's characteristics but have a different room' organization, lay out and different level of continuous education programs for nursing personnel.

RESULTS

We reported a high incidence of the infection and a non-significant difference between wards also looking to the different possibility-capacity of taking preventive measures and the different level of nursing staff continuous educational performance.

CONCLUSION

The analysis of the data we obtained was the basis to write a protocol and to start a training course for the medical and nursing personnel of the four wards on the managing of patients infected with Cd infection. On March 2011 we started a one year longitudinal study about the Cd infections in the same wards with the purpose of evaluating the adherence to the protocol, monitoring the incidence of infection and studying the risk factors of the infected patients related to the proper use of the protocol on Cd.

Integrative analysis of gene expression profiling and high-resolution genomic copy number in gastrointestinal stromal tumor (GIST)

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Background: Besides mutually exclusive cKIT or PDGFRA mutations, sequential accumulation of other genetic events may be involved in GISTs development and progression, but very few data is still available. Methods: Fresh tissues specimens of GISTs from 10 patients (9 gastric and 1 intestinal) were collected and used for RNA and DNA extraction, labeled and hybridized to HG-U133Plus 2.0 and SNP array 6.0, respectively (Affymetrix). Six patients had exon 9 or exon 11 c-KIT mutation, two PDGFRA mutation, and other two wild-type disease. Gene expression data were quantified by the RMA algorithm, filtered and analysed with supervised techniques (SAM algorithm). Genomic copy number data were analysed with Partek Genomic Suite software against a reference set of 90 Ceu HapMap individuals using a segmentation algorithm with stringent p-value cutoff. Results: Almost all patients exhibited both macroscopic cytogenetic alterations and cryptic microdeletions or amplifications by SNP-array copy number data analysis. The most frequent chromosomal alterations were: 14q complete or partial deletion (7/10), chromosome 19 monosomy (3/10), 22q and 1p deletion (2/10), chromosome 5 trisomy (2/10). The minimal overlapping region ranged from 14q22.3 to 14q32.33, covering a region including 320 genes. The integration of copy number and gene expression data showed that at least 40% of the genes inside the 14q deleted region were significantly downregulated (FDR<10%) in comparison to 14q-diploid patients. In this region several tumor suppressor genes involved in cell cycle checkpoint control (SNW1, CHES1, PPP2R5E), apoptosis induction (PPM1A, MOAP1, PPP1R13B), DNA damage response (MLH3, TDP1), WNT/Notch pathway inhibition (NUMB, DACT1, SEL1L) are located. Conclusions: A wide spectrum of genetic aberrations in GISTs may occur besides c-KIT and PDGFRA mutations. The most frequent is 14q deletion that leads to a significant downregulation of many putative tumor suppressor genes. Combining gene expression and high resolution genomic copy number analysis could identify new haploinsufficient tumor suppressor genes involved in GISTs pathogenesis and tumor progression.

No significant financial relationships to disclose.

Immune response in healthy volunteers vaccinated with killed leishmanial promastigotes plus BCG. I: Skin-test reactivity, T-cell proliferation and interferon-gamma production

This study reports the results of a vaccine trial established to study the cellular immune responses in vivo (skin-test reactivity) and in vitro (T-cell proliferation and interferon-gamma production) to both leishmanial and mycobacterial antigens following vaccination of healthy volunteers from a leishmaniasis-endemic area with killed leishmanial promastigotes, with or without BCG (Bacille Calmètte-Guerin). Skin tests were performed using purified protein derivative of tuberculin (PPD) and leishmanial antigen in 692 volunteers, and 208 doubly negative subjects (< or = 7 mm induration) were selected to participate in the trial. The study subjects were divided into four vaccine groups: (A) killed promastigotes plus BCG, (B) BCG alone, (C) killed promastigotes alone, and (D) placebo. Three vaccine doses were administered at 6-10-week intervals. The skin-test responses to PPD and leishmanial antigen were reassessed at 4-6- and 12-18-month follow-ups. The results of this trial demonstrated that the combined vaccine, i.e. killed promastigotes of Leishmania plus BCG, results in the stimulation of an immune response to both leishmania and mycobacterial antigens in a high percentage of vaccines (> 85%), manifested either by skin-test conversion, lymphocyte proliferation and/or interferon-gamma production. This was evident after the first dose of vaccine for lymphocyte proliferation and interferon-gamma production and was maintained for a year after the three doses of vaccine. Group B (which received BCG alone), responded as well as group A to PPD but not as well to leishmanial antigen. The reverse was true for group C which received promastigotes alone. Group A attained a 38% leishmanin skin-test conversion at the 4-6-month follow-up, which was associated with double PPD/leishmanial antigen responder status. In contrast, a 35% skin-test conversion was found at the 12-18-month follow-up in group C (promastigotes alone), but this was not associated with responses to PPD. A significant percentage of conversion was observed in the placebo group at the 12-18-month follow-up, both to PPD (58%) and leishmanial (21%) antigens, which suggests either environmental exposure to mycobacterial or leishmanial antigens during the vaccine trial or, more probably, a response to the repeated leishmanial skin tests. Further studies are required to determine whether the presence of proliferative and/or interferon-gamma responses in the absence of a skin-test response are sufficient indicators of potential vaccine success.

Interaction with extracellular matrix proteins influences Lsh/Ity/Bcg (candidate Nramp) gene regulation of macrophage priming/activation for tumour necrosis factor-alpha and nitrite release

The murine resistance gene Lsh/Ity/Bcg regulates activation of macrophages for tumour necrosis factor-alpha (TNF-alpha)-dependent production of nitric oxide mediating antimicrobial activity against Leishmania, Salmonella and Mycobacterium. As Lsh is differentially expressed in macrophages from different tissue sites, experiments were performed to determine whether interaction with extracellular matrix (ECM) proteins would influence the macrophage TNF-alpha response. Plating of bone marrow-derived macrophages onto purified fibrinogen or fibronectin-rich L929 cell-derived matrices, but not onto mannan, was itself sufficient to stimulate TNF-alpha release, with significantly higher levels released from congenic B10.L-Lshr compared to C57BL/10ScSn (Lshs) macrophages. Only macrophages plated onto fibrinogen also released measurable levels of nitrites, again higher in Lshr compared to Lshs macrophages. Addition of interferon-gamma (IFN-gamma), but not bacterial lipopolysaccharide or mycobacterial lipoarabinomannan, as a second signal enhanced the TNF-alpha and nitrite responses of macrophages plated onto fibrinogen, particularly in the Lshr macrophages. Interaction with fibrinogen and fibronectin also primed macrophages for an enhanced TNF-alpha response to leishmanial parasites, but this was only translated into enhanced nitrite responses in the presence of IFN-gamma. In these experiments, Lshr macrophages remained superior in their TNF-alpha responses throughout, but to a degree which reflected the magnitude of the difference observed on ECM alone. Hence, the specificity for the enhanced TNF-alpha responses of Lshr macrophages lay in their interaction with fibrinogen and fibronectin ECM, while a differential nitrite response was only observed with fibrinogen and/or IFN-gamma. The results are discussed in relation to the possible function of the recently cloned candidate gene Nramp, which has structural identity to eukaryote transporters and an N-terminal cytoplasmic proline/serine-rich putative SH3 binding domain.

Filariasis focus due to Mansonella ozzardi and Mansonella perstans in the Amazon Federal Territory of Venezuela

The presence of filariasis was investigated through Knott's method in 40 Curripaco Indians from communities located on the Casiquiare and Guainia Rivers in the Amazon Federal Territory of Venezuela. The results gave an 82.5% prevalence for infections with Mansonella perstans and 30% for infections with M. ozzardi (mixed infections with M. perstans). In almost all the patients the parasite load was greater for M. perstans and varied between 1 and 327 microfilariae per ml. This paper presents for the first time the presence of a transmission focus of M. perstans in the Amazon Federal Territory and confirms the finding of M. ozzardi in the region.

Immunotherapy of localized, intermediate, and diffuse forms of American cutaneous leishmaniasis

The clinical efficacy of immunotherapy for localized American cutaneous leishmaniasis with a combination of heat-killed Leishmania mexicana amazonensis promastigotes and viable BCG (bacille Calmette Guérin) has been compared with meglumine antimoniate chemotherapy and with BCG alone in a controlled clinical study in 217 patients. The results in the first two groups were comparable, with greater than 90% clinical cures with an average time of 16-18 w required for healing. The cure rate was considerably lower (42%) and more prolonged in the group receiving BCG alone. Secondary effects were observed in less than 5% of the patients receiving combined immunotherapy or BCG alone. In contrast, 49% of the patients receiving chemotherapy showed side effects. High therapeutic efficacy was also observed using combined immunotherapy in patients with intermediate and diffuse cutaneous leishmaniasis who were previously unresponsive to chemotherapy. Cure or clinical improvement was seen in all 11 patients with intermediate forms of the disease, and marked clinical improvement was observed in 9 of 10 patients with diffuse disease. The results on the efficacy of the combined vaccine in immunotherapy for American cutaneous leishmaniasis provide a strong rationale for studying its effectiveness in prophylactic trials.