Differential expression and characterization of a member of the mucin-associated surface protein family secreted by Trypanosoma cruzi

We describe the characterization, purification, expression, and location of a 52-kDa protein secreted during interaction between the metacyclic form of Trypanosoma cruzi and its target host cell. The protein, which we have named MASP52, belongs to the family of mucin-associated surface proteins (MASPs). The highest levels of expression of both the protein and mRNA occur during the metacyclic and bloodstream trypomastigote stages, the forms that infect the vertebrate host cells. The protein is located in the plasma membrane and in the flagellar pockets of the epimastigote, metacyclic, and trypomastigote forms and is secreted into the medium at the point of contact between the parasite and the cell membrane, as well as into the host-cell cytosol during the amastigote stage. IgG antibodies specific against a synthetic peptide corresponding to the catalytic zone of MASP52 significantly reduce the parasite's capacity to infect the host cells. Furthermore, when the protein is adsorbed onto inert particles of bentonite and incubated with a nonphagocytic cell culture, the particles are able to induce endocytosis in the cells, which seems to demonstrate that MASP52 plays a role in a process whereby the trypomastigote forms of the parasite invade the host cell.     

Migratory activation of primary cortical microglia upon infection with Toxoplasma gondii

Disseminated toxoplasmosis in the central nervous system (CNS) is often accompanied by a lethal outcome. Studies with murine models of infection have focused on the role of systemic immunity in control of toxoplasmic encephalitis, while knowledge remains limited on the contributions of resident cells with immune functions in the CNS. In this study, the role of glial cells was addressed in the setting of recrudescent Toxoplasma infection in mice. Activated astrocytes and microglia were observed in the close vicinity of foci with replicating parasites in situ in the brain parenchyma. Toxoplasma gondii tachyzoites were allowed to infect primary microglia and astrocytes in vitro. Microglia were permissive to parasite replication, and infected microglia readily transmigrated across transwell membranes and cell monolayers. Thus, infected microglia, but not astrocytes, exhibited a hypermotility phenotype reminiscent of that recently described for infected dendritic cells. In contrast to gamma interferon-activated microglia, Toxoplasma-infected microglia did not upregulate major histocompatibility complex (MHC) class II molecules and the costimulatory molecule CD86. Yet Toxoplasma-infected microglia and astrocytes exhibited increased sensitivity to T cell-mediated killing, leading to rapid parasite transfer to effector T cells in vitro. We hypothesize that glial cells and T cells, besides their role in triggering antiparasite immunity, may also act as "Trojan horses," paradoxically facilitating dissemination of Toxoplasma within the CNS. To our knowledge, this constitutes the first report of migratory activation of a resident CNS cell by an intracellular parasite.     

Clinical impact of unclassified variants of the BRCA1 and BRCA2 genes

Women who carry a pathogenic mutation in BRCA1 or BRCA2 have high risks of developing breast and ovarian cancers. The functional effect of many missense variants on BRCA1 and BRCA2 protein function is not known. Here, the authors construct a historical cohort of 4030 female first-degree relatives of 1345 unselected patients with ovarian cancer who have been screened for BRCA1 and BRCA2 mutations. The authors compared the risks by the age of 80 years for all cancers combined in female first-degree relatives of women with a pathogenic mutation, women with a variant of unknown significance (unclassified variant) and non-carriers. The cumulative risk of cancer among the relatives of patients with a pathogenic mutation was much higher than the risk in relatives of non-carriers (50.2% vs 28.5%; HR=2.87, p<10(-4)). In contrast, the cumulative risk of cancer among relatives of patients carrying an unclassified variant was similar to the risk of cancer for relatives of non-carriers (27.6% vs 28.5%; HR=1.08, p=0.79). The authors used three different algorithms to predict the pathogenicity of unclassified variants and compared their penetrance with non-carriers. In this sample, only Align Grantham Variation Grantham Deviation appeared to predict penetrance based on first-degree relatives.     

Sketching the first 45 years of the journal Psychophysiology (1964-2008): a co-word-based analysis

This article presents a keyword-based bibliometric study of the thematic evolution of the journal Psychophysiology since its first publication in 1964 until 2008. Bibliometric maps showing the most relevant associations among the main topics treated by the journal are provided separately for the periods 1964-1978, 1979-1988, 1989-1998, and 1999-2008. These maps offer insight into the conceptual structure of psychophysiology as a research discipline and help to visualize the division of the field into several interconnected subfields. Bibliometric maps created by co-word analysis can be used by both experts and novices to understand the current state of the art of a scientific field and to predict where future research could lead.     

High-resolution melting analysis for identification of the Cryptococcus neoformans-Cryptococcus gattii complex

We have developed a two-step method based on high-resolution melting (HRM) that reliably identifies species from the Cryptococcus species complex (Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, and Cryptococcus gattii). Our results indicate that HRM can provide a fast protocol to identify and distinguish among the main Cryptococcus species.     

Wide dispersion of ST175 clone despite high genetic diversity of carbapenem-nonsusceptible Pseudomonas aeruginosa clinical strains in 16 Spanish hospitals

During the COMParative Activity of Carbapenems Testing (COMPACT) surveillance study, 448 Pseudomonas aeruginosa clinical isolates were obtained from 16 Spanish hospitals. Nonsusceptibility (EUCAST breakpoints) to imipenem (35%), meropenem (33%), and/or doripenem (33%) was observed with 175 isolates (39%). Simultaneous resistance to these three drugs was observed with 126 of the 175 isolates (72%). Except for colistin, high resistance rates were observed among noncarbapenem antibiotics. Clonal relatedness was investigated by pulsed-field gel electrophoresis (PFGE) with SpeI, discriminating 68 patterns. Multilocus sequence typing (MLST) was performed on 84 isolates representing different PFGE types and all participating hospitals. Thirty-nine sequence types (STs) could be distinguished, and of these, ST175 (48 isolates, 10 hospitals), ST646 (16 isolates, 4 hospitals), ST532 (13 isolates, 3 hospitals), and ST111 (13 isolates, 7 hospitals) were the most frequently encountered. Minimum-spanning tree analysis confirmed a wide dissemination of different clones among participant hospitals, particularly ST175. PFGE pattern comparison within the four most frequent STs revealed that ST175 isolates were relatively uniform, while ST646, ST532, and ST111 isolates were highly diverse, with almost every isolate belonging to a unique pulsotype, even when originating from the same center. The population of carbapenem-nonsusceptible P. aeruginosa isolates from 16 hospitals is highly diverse, with one ST (ST175) representing a highly conserved clone disseminated in 10 of the 16 participant hospitals. This ST175 clone should be added to the list of P. aeruginosa clones at high risk for epidemic spread, such as the Liverpool, Manchester, and Melbourne clones previously found in cystic fibrosis patients and ST235 in the nosocomial setting.     

Individual effect-site concentrations of propofol at return of consciousness are related to the concentrations at loss of consciousness and age in neurosurgical patients

Study ObjectiveTo investigate whether a patient's propofol effect-site concentration at return to consciousness (ROC) was related to the propofol effect-site concentration at loss of consciousness (LOC) and to patients' individual demographic parameters.DesignProspective study.SettingOperating room.Patients31 ASA physical status I and II neurosurgical patients with Glasgow Coma Score > 15, and scheduled to receive total intravenous anesthesia with effect-site target controlled infusion (TCI) of propofol and remifentanil.InterventionsA constant propofol infusion was administered until LOC. At LOC, remifentanil started with a plasma concentration target of 2.5 ng mL^?1.Main ResultsPropofol concentration at LOC was 4.9 ± 1 μg mL^?1. At ROC, propofol and remifentanil concentrations were 1.16 ± 0.3 μg mL^?1 and 3.41 ± 1.5 ng mL^?1. Significant correlation was observed between propofol concentrationa at ROC and LOC, between propofol concentration at ROC and patient age (48.7 ± 15 yrs), and between propofol concentrations at ROC and LOC, divided by patient's age.ConclusionsThe correlation between propofol concentrations at ROC and LOC was improved by inclusion of patient age data.     

Beneficio de la biopsia del ganglio linfático centinela en pacientes con carcinoma in situ de mama

Introduction

Patients with a diagnosis of breast ductal carcinoma in situ (DCIS) have a low risk of developing axillary metastases. The use of sentinel node biopsy in this group of patients is controversial. The objective of this study is to determine if the sentinel node biopsy benefits a subgroup of patients with DCIS.

Patients and method

Between April 2002 and December 2007, patients with a diagnosis of DCIS and who underwent a sentinel node biopsy were included in the study. In our centre the sentinel node biopsy was performed in patients with DCIS who required a mastectomy, high grade and >2 cm DCIS and palpable DCIS.

Results

Forty-seven patients were included in the study. In all cases the sentinel node was identified. Twenty-five (53.1%) patients underwent a mastectomy due to extensive DCIS; 14 of these (56%) with immediate reconstruction with implants. Twenty-five (53.1%) patients had high grade DCIS. In 7 (14.8%) patients the tumour was palpable. Fourteen patients (29.7%) were upgraded to invasive breast cancer in the definitive histology. In 2 (4.2%) patients who underwent a mastectomy a positive sentinel node was found.

Conclusions

Performing sentinel node biopsy in this group of DCIS patients has lead us to identify 4% of patients with positive sentinel nodes. Furthermore, 29.7% of the patients have avoided a second invasive diagnostic procedure for definitive histology. For these reasons we consider it appropiate to perform sentinel node biopsy in this subgroup of patients with DCIS of the breast.     

A single-center study of C1q nephropathy in children

C1q nephropathy (C1qN) is a rare idiopathic glomerulopathy typically seen in adolescents and young adults. All kidney biopsies done from 2002 to 2007 were analyzed (264). Thirteen cases of C1qN from 212 (6.6%) native biopsies and one case out of 52 (1.9%) transplant biopsies were reviewed regarding demographic features, clinical presentation, histopathology, treatment, and outcome. Age varied from 1 to 18 years; half were boys. Ten children (71.4%) presented with nephrotic syndrome (NS). The most common histopathology found was diffuse mesangial proliferative glomerulonephritis (DMP) by light microscopy (LM), with diffuse granular staining for C1q predominantly in the mesangium. Children with either NS or persistent gross hematuria received prednisone and angiotensin-converting enzyme inhibitors (ACEi) (11). Median follow-up was 36 months. Steroid response was complete in 6 patients (54.5%). Those with steroid resistance (5) or steroid dependence (2) received further immunosuppression with mycophenolate mofetil (MMF) or tacrolimus (Tac). Three children achieved complete remission and four partial remission. Frequent relapses were seen in 4/14 patients. Renal survival was 100%. Our report reveals a high incidence of C1qN in pediatric patients, with variable clinical presentation. Despite a high incidence of steroid resistance among those with NS, an excellent response was observed with the addition of further immunosuppression.