Examining the relation between bilingualism and age of symptom onset in frontotemporal dementia

Bilingualism is thought to confer advantages in executive functioning, thereby contributing to cognitive reserve and a later age of dementia symptom onset. While the relation between bilingualism and age of onset has been explored in Alzheimer's dementia, there are few studies examining bilingualism as a contributor to cognitive reserve in frontotemporal dementia (FTD). In line with previous findings, we hypothesized that bilinguals with behavioral variant FTD would be older at symptom onset compared to monolinguals, but that no such effect would be found in patients with nonfluent/agrammatic variant primary progressive aphasia (PPA) or semantic variant PPA. Contrary to our hypothesis, we found no significant difference in age at symptom onset between monolingual and bilingual speakers within any of the FTD variants, and there were no notable differences on neuropsychological measures. Overall, our results do not support a protective effect of bilingualism in patients with FTD-spectrum disease in a U.S. based cohort.

Abstract P4-10-09: Delay in diagnosis of breast cancer in Mexican young women: Report of the “Joven y Fuerte” prospective cohort pilot phase

Background: Delay in diagnosis and treatment initiation of breast cancer (BC) has been associated with advanced stages and poor outcome. In developed countries, age has not been solely reported as an independent predictor of diagnosis delay. In Mexico, median time since tumor detection to treatment initiation is about 7 months, but young women are underrepresented in these studies. We aim to describe time intervals related to diagnosis in Mexican young women with BC (YWBC).

Methods: Newly diagnosed YWBC were invited to participate as part of this prospective cohort. Patient accrual began in November 2014 at two public cancer centers in Mexico. Patients completed self-report surveys including questions regarding mode of detection, time from first symptom to medical appointment (patient interval) and time from first symptom to diagnosis (total interval). Pearson chi-square tests were used to examine the effects of patient and clinical characteristics on patient interval and clinical stage.

Results: 96 YWBC with median age at diagnosis of 35 y (range 21-40) were enrolled in our pilot phase. 82.3% had tumor detected by self or partner. 62.5% of YWBC were diagnosed as locally advanced disease (IIB-IIIC). Median tumor size was 3.5 cm (0.5-12.0), with node involvement in 66.7%. 53.1% of YWBC had a patient interval of <6 months, but roughly 27.1% had a total interval <6 months. While only 13.5% had a patient interval >12 months, 39.6% reached a total interval >12 months. Patient interval and clinical stage were not significantly associated with occupation, education, marital status, current partner or method of detection.

 N(%)TimePatient intervalTotal interval<1 month29 (30.2)7 (7.3)1-3 months18 (18.8)9 (9.4)4-6 months4 (4.2)10 (10.4)7-12 months10 (10.4)24 (25.0)>12 months13 (13.5)38 (39.6)No symptoms0 (0.0)3 (3.1)NA22 (22.9)5 (5.2)Method of Detection Patient/Partner detected tumor79 (82.3)Clinical detection0 (0.0)Image detected9 (94)NA8 (8.3)Clinical stage 02 (2.1)IA13 (13.5)IB1 (1.0)IIA14 (14.6)IIB17 (17.7)IIIA28 (29.2)IIIB8 (8.3)IIIC7 (7.3)IV6 (6.2)

Conclusions: In this cohort, most patients had a greater total delay than previously reported in Mexico, possibly attributed to long health-system intervals, which could contribute to worse outcomes in YWBC. The prospective nature of this study allows the recollection of biologic characteristics, treatment scheme and adherence to treatment, to determine their impact on clinical outcome besides diagnosis delay. “Joven & Fuerte”, the first dedicated program for the care of young breast cancer patients in Latin America, aims to develop YWBC-tailored interventions to early diagnose or “downstage” BC among young women by endorsing patient navigation, increasing general population awareness and improving providers' knowledge in low-middle income countries, such as Mexico.

Citation Format: Castro-Sanchez A, Barragan-Carrillo R, Miaja M, Platas A, Martinez Cannon BA, Fonseca A, Vega Y, Bukowski A, Chapman J-A, Goss P, St. Louis J, Bargallo-Rocha JE, Mohar A, Peña-Curiel O, Villarreal-Garza CM. Delay in diagnosis of breast cancer in Mexican young women: Report of the “Joven y Fuerte” prospective cohort pilot phase [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-10-09.

Abstract P4-20-04: Young women with breast cancer in Mexico: A report of the pilot phase of the “Mujer Joven y Fuerte” prospective cohort

Background: Despite high rates of breast cancer in young women from low-and-middle-income countries (LMICs), their needs and concerns are not systematically studied or addressed. Understanding the characteristics of young women with breast cancer (YWBC) and the issues they face is of great relevance to the medical community, in order to tailor clinical interventions and supportive care for this unique and understudied patient population. The Mexican cohort “Mujer Joven y Fuerte” (Young and Strong Woman) has the goal of comprehensively characterizing and assessing the needs of YWBC in Mexico using patient- and physician-based surveys. Methods: A prospective cohort of newly diagnosed YWBC was established in November 2014 at two Mexican cancer centers in Mexico City and Monterrey. Eligible women answer web-based surveys on relevant topics including physical activity, genetics, psychosocial needs, and fertility. Clinicians complete pre-specified surveys using the US NIH BOLD Task Force common data elements registering clinical/pathologic characteristics and outcomes. Patients are evaluated at diagnosis, after 6 months, and annually for 5 years. Sub-studies assessing changes in cognition, sexual function and satisfaction, quality of life and depression/anxiety are being conducted, and biologic samples are stored for future research. Results: 96 YWBC with median age at diagnosis of 34 (21-41 y) were accrued to our pilot phase. 26% were single and 25% childless. 43% had higher education and 28% were employed. 90% presented with a self-detected mass. Clinical stage at diagnosis was distributed as follows: stage 0: 2%; I: 15%; IIA: 13%; IIB: 17%; III: 47%, and stage IV: 6%. The most frequent molecular subtype was HR+/HER2- (47%), followed by HER2+ (26%) and triple negative (21%). First follow-up results will be available shortly. Conclusions: To our knowledge, this represents the first prospective cohort of YWBC in Latin America. We are expanding this project to other centers in the region. Our findings will help develop culturally tailored interventions aimed at improving the psychosocial and medical outcomes of this vulnerable patient population.

Citation Format: Villareal-Garza CM, Platas A, Castro-Sánchez A, Miaja M, Bargalló-Rocha E, Martinez-Cannon BA, Vega Y, Fonseca A, Ramos-Elias P, Márquez-Perez CJ, Bukowski A, Goss P, St. Louis J, Chapman J-A, Partridge A, Meneses A, Mohar A. Young women with breast cancer in Mexico: A report of the pilot phase of the “Mujer Joven y Fuerte” prospective cohort [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-20-04.

[Rapid spread of the HIV-1 circular recombinant CRF02-AG in Russia and neighboring countries]

The spread of the HIV-1circular recombinant CRF02-AG in countries of the former Soviet union (Commonwealth of Independent States, CIS) was studies using partial and full genome sequences. The full-genome sequence of the CRF02-AG recombinant circulating in Russia was obtained for the first time. A Global phylogenetic tree of CRF02-AG full-genome sequences was constructed. Three distinct groups of the sequences were detected as clustered by the geographical location (CIS, South Korea, and France), which is indicative of the single-virus introduction in each of the regions mentioned above. The CIS cluster exhibiting minimum genetic diversity was, therefore, relatively young. The phylogenetic analysis of the env gene sequences within the CIS cluster made it possible to clearly discriminate three branches: two of Russian and one of Uzbek origin. The low genetic diversity within the two Russian subclusters provides evidence of at least two recent independent introductions of the CRF02-AG recombinant from Central Asia into Russia. This work was performed within the framework of the 7th Federal Research Program (FP&), Project EURIPRED (European Research Infrastructures for Poverty Related Diseases), grant agreement No.312661.

High-speed gel microelectrophoresis, a new and easy approach for detection of PCR-amplified microbial DNA from environmental and clinical samples in microgels using conventional equipment

AIMS

Microelectrophoresis allows the detection of DNA bands using minimal amounts of sample in a short time, but commonly requires the use of special equipment which is not available in all laboratories. This fact has limited the application of this technique in microbiology despite its advantages. In this work, we describe a new approach to perform gel microelectrophoresis, named high-speed gel microelectrophoresis (HSGME), and its application for rapid detection of bacteria, protozoa and viruses in clinical, vegetal and environmental samples.

METHODS AND RESULTS

Aliquots of 0.4-1 microl of PCR product were loaded in 2 cm 1% agarose microgels and electrophoresed at high voltage (125 V cm(-1)) in conventional submarine horizontal mini-slabs. By using HSGME, single-DNA bands obtained after specific-PCR useful in diagnosis of different diseases caused by micro-organisms were detected in 5 min.

CONCLUSIONS

HSGME is a rapid and easy procedure applicable to detection of microbial genes, which is carried out using conventional equipment and thus can be performed in any research and diagnostic laboratory.

SIGNIFICANCE AND IMPACT OF THE STUDY

The performance of HSGME saves up to 90% time, material and energy costs, as well as laboratory hazardous wastes including carcinogenic agents used for visualizing DNA bands.

Comparative study of red blood cell method in rat and calves blood as alternatives of Draize eye irritation test

INTRODUCTION

Red blood cell assay (RBC) is used to estimate potential irritation of tensioactive agents and detergents. Cell membrane lysis and cell protein denaturation are measured photometrically. This study was aimed to determine if rat blood cells can be used to predict eye potential irritation in the same way of calves blood cells in RBC assay.

METHODS

We evaluated 20 cosmetic formulations using rat and calves blood according to INVITOX protocol No 37. Data of media hemolysis concentration, denaturation index and the ratio of both parameters were compared with in vivo data of eye irritancy.

RESULTS

There was a significant difference (p<0.01) between H50 value when evaluated the standard SDS with red blood cell method in rat and calves blood. According to the exact probability of Fisher taking as approach the acceptance or rejection of the substance there are no significant differences between in vitro assay with calves blood and in vivo results. Not happening the same way for the RBC assay with rat blood where significant differences were obtained (p<0.01) among the classification of in vitro and in vivo test.

DISCUSSION

The RBC assay using calves blood showed better results. Several test substances were false negatives with rat blood. This high false negative rate would be correctly identified by the animal test but it may also lead to increased animal consumption. For that RBC assay with calf blood cells is preferable to the employment of rat blood as screening method with a reduction and refinement strategy.

Analysis of drug resistance-associated mutations in treatment-naïve individuals infected with different genetic forms of HIV-1 circulating in countries of the former Soviet Union

There are few data on drug resistance-associated mutations in the former Soviet Union since, studies have usually been focused on the env or gag genes for subtype information. This study examines the prevalence and patterns of resistance-associated mutations to reverse transcriptase and protease inhibitors (RTI, PRI) in 278 HIV-1-infected treatment-naïve subjects from countries of Eastern Europe, and defines characteristic polymorphisms of RT and PR sequences in HIV-1 subtype A viruses. Blood samples were collected between 1997 and 2004. Plasma RNA was used for PR-RT amplification by reverse transcription coupled with nested PCR and sequencing. Phylogenetic analysis was done with neighbor-joining trees and bootscanning. Analysis of drug resistance mutations, with Stanford University HIV Drug Resistance Database's algorithm, resulted in an overall prevalence of 12.9% resistance to RTI and 3.9% to PRI. The most frequent substitutions in the RT region were at positions 62 and 236. V77I substitution in PR was found in 47.8% of samples. Polymorphisms in subtype A sequences were identified. This is the first study reporting the prevalence and patterns of both PRI and RTI resistance-associated mutations in naïve HIV-1 infected patients from the former Soviet Union. These data underline the importance of genotypic resistance testing of chronically HIV-1-infected patients before initiating treatment, in order to select the most suitable drug regimen.

Natural resistance-associated mutations to Enfuvirtide (T20) and polymorphisms in the gp41 region of different HIV-1 genetic forms from T20 naive patients

BACKGROUND

The natural occurrence of primary resistance mutations in reverse transcriptase (RT) and protease (PR) genes of HIV-1 isolates from untreated patients has been reported and it may have important implications for the response to drug treatment. It is predictable that the same occurs in the HR1 region of gp41 sequence from patients who have never received T20 therapy, and in this regard it would be important to know not only the mutation frequencies at HR1 region but also the natural polymorphisms at resistance-associated positions present in the absence of this drug.

OBJECTIVES

The objectives of this study are to investigate the existence of natural resistance-associated mutations to T20 in HR1 gp41 region corresponding to different HIV-1 genetic forms from T20 naive patients and to determine their prevalence.

STUDY DESIGN

Two hundred HIV-1 gp41 sequences were included: subtype B: 164 (81.3%); subtype A: 15 (8.2%); subtype G: 10 (4.6%); subtype F: 6 (3.5%); subtype C: 3 (1.8%); subtype K: 1 (0.6%); and subtype D: 1 (0.6%). We analyzed the resistance-associated mutations previously described: Q32H/R, G36D/S, I37V, V38A/M, Q39R/H, Q40H, N42T/D/Q/H, N43D/S/K/Q, L44M, L45M, R46M and V69I.

RESULTS

Natural resistance mutations to T20 were found at a high frequency: 10.5%, corresponding to 9.1% in subtype B and 16.7% in non-B subtype samples. Polymorphisms were more frequent in non-B and recombinant forms than in subtype B (p<0.001). Different substitutions were related to subtypes: N42S in subtypes A, B, G and C, but not in F, Q56R in subtype A from CRF02_AG, and L54M in subtype B from CRF14_BG.

CONCLUSIONS

To our knowledge this is the first study describing natural-resistance to T20 among different HIV-1 subtypes, warranting a study of the biological significance of this mutations and their clinical relevance. The detection of differences between subtypes may have an influence on the rate and patterns of resistance in patients undergoing T20 treatment.

A role for ActA in epithelial cell invasion by Listeria monocytogenes

We assessed the role of the actin-polymerizing protein, ActA, in host cell invasion by Listeria monocytogenes. An in frame DeltaactA mutant was constructed in a hyperinvasive strain of prfA* genotype, in which all genes of the PrfA-dependent virulence regulon, including actA, are highly expressed in vitro. Loss of ActA production in prfA* bacteria reduced entry into Caco-2, HeLa, MDCK and Vero epithelial cells to basal levels. Reintroduction of actA into the DeltaactA prfA* mutant fully restored invasiveness, demonstrating that ActA is involved in epithelial cell invasion. ActA did not contribute to internalization by COS-1 fibroblasts and Hepa 1-6 hepatocytes. Expression of actA in Listeria innocua was sufficient to promote entry of this non-invasive species into epithelial cell lines, but not into COS-1 and Hepa 1-6 cells, indicating that ActA directs an internalization pathway specific for epithelial cells. Scanning electron microscopy of infected Caco-2 human enterocytes suggested that this pathway involves microvilli. prfA* bacteria, but not wild-type bacteria (which express PrfA-dependent genes very weakly in vitro) or prfA* DeltaactA bacteria, efficiently invaded differentiated Caco-2 cells via their apical surface. Microvilli played an active role in the phagocytosis of the prfA* strain, and actA was required for their remodelling into pseudopods mediating bacterial uptake. Thus, ActA appears to be a multifunctional virulence factor involved in two important aspects of Listeria pathogenesis: actin-based motility and host cell tropism and invasion.

Positive selection of mutations leading to loss or reduction of transcriptional activity of PrfA, the central regulator of Listeria monocytogenes virulence

Transcription factor PrfA controls the expression of virulence genes essential for Listeria monocytogenes pathogenesis. To gain insight into the structure-function relationship of PrfA, we devised a positive-selection system to isolate mutations reducing or abolishing transcriptional activity. The system is based on the observation that the listerial iap gene, encoding the p60 protein, is lethal if overexpressed in Bacillus subtilis. A plasmid in which the iap gene is placed under the control of the PrfA-dependent hly promoter was constructed and introduced into B. subtilis. This strain was rapidly killed when expression of iap was induced by introduction of a second plasmid carrying prfA. Two classes of B. subtilis survivor mutants were identified: one carried mutations in iap, and the second carried mutations in prfA. Sequence analysis of the defective prfA genes identified mutations in three regions of the PrfA protein: region A, between amino acids 58 and 67 in the beta-roll domain of PrfA; region B, between amino acids 169 and 193, which corresponds to the DNA-binding helix-turn-helix motif; and region C, comprising the 38 C-terminal amino acids of PrfA, which form a leucine zipper-like structure. PrfA proteins with mutations in regions B and C were unable to bind to the PrfA-binding site in the target DNA, while mutations in region A resulted in a protein still binding the target DNA but unable to form a stable complex with RNA polymerase and initiate transcription in vitro.

SmcL, a novel membrane-damaging virulence factor in Listeria

We describe here the fourth listerial membrane-damaging virulence factor, a sphingomyelinase C (SMase) that is produced specifically by the ruminant pathogen Listeria ivanovii. Its coding gene, smcL, is a monocistron expressed independently of PrfA. The smcL product, SmcL, is highly similar to the staphylococcal beta-toxin and is responsible for the differential hemolytic properties of L. ivanovii (bizonal hemolysis and CAMP-like reaction with R. equi). The role of SmcL in virulence was assessed by gene disruption and complementation. Our data show that SmcL mediates disruption of the membrane of primary phagosomes, thereby promoting bacterial intracellular proliferation. They also suggest that SmcL may play a role in host tropism. smcL is located in LIPI-2, a novel 18-kb pathogenicity island which also contains a cluster of internalin genes. LIPI-2 is unstable, L. ivanovii-specific and required for full virulence in mice and lambs.

The smcL gene of Listeria ivanovii encodes a sphingomyelinase C that mediates bacterial escape from the phagocytic vacuole

The ruminant pathogen Listeria ivanovii differs from Listeria monocytogenes in that it causes strong, bizonal haemolysis and a characteristic shovel-shaped co-operative haemolytic ('CAMP-like') reaction with Rhodococcus equi. We cloned the gene responsible for the differential haemolytic properties of L. ivanovii, smcL. It encodes a sphingomyelinase C (SMase) highly similar (> 50% identity) to the SMases from Staphylococcus aureus (beta-toxin), Bacillus cereus and Leptospira interrogans. smcL was transcribed monocistronically and was expressed independently of PrfA. Low-stringency Southern blots demonstrated that, within the genus Listeria, smcL was present only in L. ivanovii. We constructed an smcL knock-out mutant. Its phenotype on blood agar was identical to that of L. monocytogenes (i.e. weak haemolysis and no shovel-shaped CAMP-like reaction with R. equi ). This mutant was less virulent for mice, and its intracellular proliferation was impaired in the bovine epithelial-like cell line MDBK. The role of SmcL in intracellular survival was investigated using an L. monocytogenes mutant lacking the membrane-damaging determinants hly, plcA and plcB, being thus unable to grow intracellularly. Complementation of this mutant with smcL on a plasmid was sufficient to promote bacterial intracellular proliferation in MDBK cells. Transmission electron microscopy showed that SmcL mediates the disruption of the phagocytic vacuole and the release of bacteria into the cytosol. Therefore, L. ivanovii possesses a third phospholipase with membrane-damaging activity that, together with PlcA and PlcB, may act in concert with the pore-forming toxin Hly to mediate efficient escape from the vacuolar compartment. The 5' end of smcL is contiguous with the internalin locus i-inlFE, which is also specific to L. ivanovii and is required for full virulence in mice. Thus, smcL forms part of a novel virulence gene cluster in Listeria that is species specific.

Functional similarities between the Listeria monocytogenes virulence regulator PrfA and cyclic AMP receptor protein: the PrfA* (Gly145Ser) mutation increases binding affinity for target DNA

Most Listeria monocytogenes virulence genes are positively regulated by the PrfA protein, a transcription factor sharing sequence similarities with cyclic AMP (cAMP) receptor protein (CRP). Its coding gene, prfA, is regulated by PrfA itself via an autoregulatory loop mediated by the upstream PrfA-dependent plcA promoter. We have recently characterized prfA* mutants from L. monocytogenes which, as a result of a single amino acid substitution in PrfA, Gly145Ser, constitutively overexpress prfA and the genes of the PrfA virulence regulon. Here, we show that about 10 times more PrfA protein is produced in a prfA* strain than in the wild type. Thus, the phenotype of prfA* mutants is presumably due to the synthesis of a PrfA protein with higher promoter-activating activity (PrfA*), which keeps its intracellular levels constantly elevated by positive feedback. We investigated the interaction of PrfA and PrfA* (Gly145Ser) with target DNA. Gel retardation assays performed with a DNA fragment carrying the PrfA binding site of the plcA promoter demonstrated that the PrfA* mutant form is much more efficient than wild-type PrfA at forming specific DNA-protein complexes. In footprinting experiments, the two purified PrfA forms interacted with the same nucleotides at the target site, although the minimum amount required for protection was 6 to 7 times lower with PrfA*. These results show that the primary functional consequence of the Gly145Ser mutation is an increase in the affinity of PrfA for its target sequence. Interestingly, similar mutations at the equivalent position in CRP result in a transcriptionally active, CRP* mutant form which binds with high affinity to target DNA in the absence of the activating cofactor, cAMP. Our observations suggest that the structural similarities between PrfA and CRP are also functionally relevant and support a model in which the PrfA protein, like CRP, shifts from transcriptionally inactive to active conformations by interaction with a cofactor.

Evidence for expressional crosstalk between the central virulence regulator PrfA and the stress response mediator ClpC in Listeria monocytogenes

Virulence is a multifactorial trait which depends on the coordinated expression of many bacterial products, hence it is to be expected that the regulatory circuits that control the relevant genetic determinants are somehow interconnected. Two pleiotropic regulatory elements acting at different levels, the transcription factor PrfA which controls virulence gene expression and the potential chaperone ClpC which is involved in tolerance to environmental stress, are required for Listeria monocytogenes survival within the host. We analyzed the influence of PrfA on clpC expression in L. monocytogenes. clpC transcription is maximal under heat-shock conditions, i.e. at 42 degrees C, and is very weak or undetectable at 37 degrees C. In a prfA* mutant which constitutively overexpresses PrfA and PrfA-dependent virulence genes, clpC transcription dropped to basal levels during exponential growth at 42 degrees C. This repression was not observed during stationary phase, indicating growth phase-dependent regulation of clpC. Culture in charcoal-treated medium, which triggers in wild-type strains the transcriptional activation of the PrfA regulon, also caused a strong downregulation of clpC. Moreover, in a prfA deletion mutant, clpC transcription during exponential growth at 37 degrees C was clearly enhanced, reaching the same high levels of the wild-type at 42 degrees C. Overall, our results indicate that clpC expression is negatively controlled at the transcriptional level, directly or indirectly, by the central virulence regulator PrfA.