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PubMed1991

Listeria monocytogenes isolates can be classified into two major types according to the sequence of the listeriolysin gene.

The nucleotide sequence of a 3.5-kb BamHI fragment from Listeria monocytogenes 12067, a human clinical isolate of serotype 4b, has been determined. The DNA fragment harbors the gene for listeriolysin, part of the gene for a phosphatidylinositol-specific phospholipase C, and part of the gene for a metalloprotease. Comparison of the sequence with corresponding sequences from two other L. monocytogenes isolates revealed a significant number of nucleotide differences. Several of the differences give rise to amino acid substitutions. The most variable region was the examined part of the mpl gene, whereas the lisA gene showed a relatively high degree of conservation, particularly at the amino acid level. To analyze the pattern of sequence variability in the lisA gene, a 160-bp region covering nine nucleotide differences was sequenced from 36 isolates of different origins. This work showed that the strains can be grouped into two major types according to the nucleotide sequences. Oligonucleotide probing of a larger number of L. monocytogenes isolates showed that the observed differences can be used to subdivide the species. The data suggest a correspondence between the sequence type of the lisA gene and flagellar antigens. Assays based on hybridization or the polymerase chain reaction with type-specific oligonucleotides may provide fast and easy alternative methods for strain typing.

Amino Acid Sequence↗

PubMed1992

Coordinate regulation of virulence genes in Listeria monocytogenes requires the product of the prfA gene.

The prfA gene of Listeria monocytogenes encodes a protein that activates transcription of the listeriolysin gene (lisA). In order to explore the role of the prfA gene product in the pathogenesis of listerial infection, we constructed a site-directed insertion mutation in prfA by the chromosomal integration of a novel suicide vector containing a portion of the prfA coding region. This mutation not only transcriptionally silenced the listeriolysin (lisA) gene but also abrogated production of specific RNA transcripts corresponding to the phosphatidylinositol-specific phospholipase C (pic) and metalloprotease (mpl) genes, two further virulence gene products expressed only by pathogenic Listeria strains. The strain was also found to be avirulent when tested in a mouse model of listerial infection. The concomitant loss of multiple characteristics such as production of LisA, Pic, Mpl, and loss of virulence in a mouse infection model is the result of a mutation in a single gene and demonstrates that the prfA gene product is a positive regulator of multiple virulence determinants in L. monocytogenes.

Animals↗

PubMed2001

Communicating with children and adolescents about their cancer.

BACKGROUND: Communication with children and adolescents with cancer about their disease and treatment and the implications of these is an important aspect of good quality care. It is often poorly performed in practice. Various interventions have been developed that aim to enhance communication involving children or adolescents with cancer. OBJECTIVES: To examine the effects of interventions to enhance communication with children and/or adolescents about their cancer, its treatment and their implications. SEARCH STRATEGY: The following electronic databases were searched: Cochrane Library; Medline; PsycLit; Cinahl; Cancerlit; EMBASE; Sociofile; Health Management Information Consortium; ASSIA; LISA; ERIC; PAIS; Information Science Abstracts; Dissertation Abstracts; JICST; Pascal; Linguistics and Language Behavior Abstracts; Mental Health Abstracts; AMED; MANTIS. Bibliographies of identified studies were also checked and contact made with experts in the field. SELECTION CRITERIA: Randomised and non-randomised controlled trials and before and after studies that evaluated the effects of interventions to enhance communication with children and/or adolescents about their cancer, treatment and related issues. DATA COLLECTION AND ANALYSIS: Data relating to the interventions, populations and outcomes studied and the design and methodological quality of included studies were extracted by one reviewer and checked by another reviewer. A narrative summary of the results is presented. MAIN RESULTS: Six studies met the criteria for inclusion. They were diverse in terms of the interventions evaluated, study designs used, types of people who participated and the outcomes measured. One study of a computer-assisted education programme reported improvements in knowledge and understanding about blood counts and cancer symptoms. Two out of two studies of school reintegration programs reported improvements in some aspects of psychosocial wellbeing (one in anxiety and one in depression), social wellbeing (two in social competence and one in social support) and behavioural problems; and one reported improvements in physical competence. REVIEWER'S CONCLUSIONS: Interventions to enhance communication involving children and adolescents with cancer have not been widely or rigorously assessed. The weak evidence that exists suggests that some children and adolescents with cancer may derive some benefit from specific information-giving programs and from interventions that aim to facilitate their reintegration into school and social activities. More research is needed to investigate the effects of these and other related interventions.

Adolescent↗

PubMed1994

The early effects of gamma knife on 40 cases of acoustic neurinoma.

Early results of gamma radiosurgery on 44 cases of acoustic neurinoma were studied by follow-up MRIs and changes of neurological signs every 3 months. Mean follow-up period was 12 (3 to 20) months. Enhanced MRI revealed that the central low intensity signal area (LISA) appeared at 3 to 6 months after the treatment, which was re-enhanced at 6 to 9 months, then the tumours begun to decrease in size at 9 to 12 months, which observation was noted in 11 out of 44 cases (25%). The other tumours were unchanged in size. Regarding the side effects, facial palsy appeared in 7 cases (16%) after the treatment, of whom 3 cases have improved. Trigeminal nerve palsy was found in 3 cases (7%). Deterioration of hearing was found in 11 out of 21 cases (52%) who had hearing disturbances before treatment. The pathological study of a treated tumour at 11 months revealed that central LISA was found as complete necrosis and degeneration of tumour cells and vessels with thickening walls found at the margin of the tumour. MRI is not only useful for the dose planning of radiosurgery but valuable for the follow-up study of treated tumours.

Adult↗

PubMed2004

Detection of PCR amplicons from bacterial pathogens using microsphere agglutination.

For rapid and inexpensive detection of polymerase chain reaction (PCR) amplicons, a novel microsphere agglutination assay has been developed. PCR is carried out using biotinylated forward and reverse primers, and the amplified DNA fragments are able to agglutinate streptavidin-coated microspheres (5.7 microm in diameter). Purification of PCR amplicons is unnecessary when initial primer concentrations are 250 nM. Agglutination can be identified visually within 2 min without any additional equipment or reagents. Using listeriolysin (lisA)-specific biotinylated primers, we have successfully detected and identified Listeria monocytogenes lisA+ cells among Salmonella typhimurium, Staphylococcus aureus, Campylobacter jejuni and Escherichia coli O157:H7 cells. The simplicity of this protocol considerably reduces the time and cost of diagnostic PCR experiments. This procedure is potentially useful for various studies and field applications.

Agglutination↗

PubMed1999

A comparison of ELISA assays as routine diagnostic test for detection of autoantibodies against extractable nuclear antigens.

OBJECTIVE: In an analytical evaluation, commercially available ELISA test kits for detection of antibodies directed against extractable nuclear antigens (ENA) were compared with the currently used combination of counterimmunoelectrophoresis and immunoblotting. DESIGN: Three screening ELISAs and two typing ELISAs were tested. These methods were fairly simple, easy to perform and "user friendly," because most of the reagents were ready to use. RESULTS: The agreement with the current methods was good, but the screening as well as typing ELISAs proved to be more sensitive, especially with regard to detection of SS-A auto-antibodies. The cut-off range of one screening assay was not well established and one typing assay suffered from problems with inaccuracy of package insert, purity of antigen and standardisation of reactivity (possibly caused by differences in amount of coated antigen). The other three ELISAs were reliable and sensitive for detection of ENA auto-antibodies. CONCLUSIONS: The ELISA ENA screen assays ENA-LISA polyvalent and Milenia ENA screen and typing assays ENA-LISA are reliable and sensitive for detection of autoantibodies in clinical specimens without substantial false negatives.

Autoantibodies↗

PubMed2002

Kinetic and mechanistic study of the atmospheric oxidation by OH radicals of allyl acetate.

Acetates are emitted into the atmosphere by several anthropic and natural sources. To better evaluate the environmental impact of these compounds, OH-induced oxidation kinetic and mechanism of allyl acetate (CH3C(O)OCH2-CH=CH2) have been investigated at room temperature and atmospheric pressure using three environmental chambers: an indoor Teflon-film bag (LISA, Créteil), an indoor Pyrex photoreactor (LISA, Créteil), and the outdoor Smog chamber EUPHORE (Valencia). Rate constant of the reaction of allyl acetate with OH radicals was determined by relative rate technique in the indoor Teflon-film bag. It is (30.6 +/- 3.1) x 10(-12) cm3 molecule-1 s-1. Mechanistic experiments were performed in the indoor photoreactor and in the outdoor Smog chamber EUPHORE. The main oxidation products observed by FTIR in both chambers were acetoxyacetaldehyde and formaldehyde. From these data, a mechanism was developed to describe the OH-induced oxidation of this acetate in the presence of NOx. Finally, atmospheric impact of allyl acetate emissions was evaluated using kinetic and mechanistic results.

Acetates↗

PubMed2003

A symbolic-connectionist theory of relational inference and generalization.

The authors present a theory of how relational inference and generalization can be accomplished within a cognitive architecture that is psychologically and neurally realistic. Their proposal is a form of symbolic connectionism: a connectionist system based on distributed representations of concept meanings, using temporal synchrony to bind fillers and roles into relational structures. The authors present a specific instantiation of their theory in the form of a computer simulation model, Learning and Inference with Schemas and Analogies (LISA). By using a kind of self-supervised learning, LISA can make specific inferences and form new relational generalizations and can hence acquire new schemas by induction from examples. The authors demonstrate the sufficiency of the model by using it to simulate a body of empirical phenomena concerning analogical inference and relational generalization.

Generalization, Psychological↗

PubMed1990

Identification of a gene that positively regulates expression of listeriolysin, the major virulence factor of listeria monocytogenes.

We have isolated, by molecular cloning and genetic complementation of a listeriolysin-negative mutant, a gene required for the expression of this virulence factor in Listeria monocytogenes. The mutant strain SLCC53, which was nonhemolytic and avirulent, harbored a deletion of 450 base pairs located approximately 1500 base pairs upstream of the listeriolysin gene. No transcripts corresponding to the listeriolysin gene were detected in the mutant. DNA sequencing of this region from the hemolytic strain EGD revealed that the region deleted in the mutant would abrogate expression of a 27-kDa polypeptide. Introduction of a recombinant plasmid expressing this 27-kDa polypeptide restored hemolytic activity to the mutant and increased the hemolytic activity of the wild-type L. monocytogenes strain EGD. We have designated the gene encoding the 27-kDa polypeptide prfA, for positive regulatory factor of listeriolysin (lisA) expression. The prfA gene regulates transcription of the lisA gene positively.

Amino Acid Sequence↗

PubMed2004

School-based prevention of depressive symptoms in adolescents: a 6-month follow-up.

OBJECTIVE: Depressive disorders in adolescents are a widespread problem with extensive psychosocial consequences. The authors designed a school-based program to prevent the increase in depressive symptoms. The authors expect the program to reduce dysfunctional automatic thoughts and improve social skills and thus prevent the increase in depressive symptoms. METHOD: The design includes a training group and a nontreatment control group with pre- and post-measurement and 3- and 6-month follow-up. The authors followed up 324 eighth graders in both groups. School classes were randomly assigned to one of the two groups. The prevention program, LISA-T, is based on cognitive-behavioral therapy concepts and targets of cognitive and social aspects. It comprises 10 meetings of 1.5 hours in a regular school setting. RESULTS: Increases in depressive symptoms in nondepressed adolescents in the training group were prevented over a 6-month period. Furthermore, adolescents with subsyndromal depression in the training group reported fewer symptoms, whereas depressive symptoms within the control group did not change. However, the groups did not differ with regard to social skills, frequency of negative automatic thoughts, and depressive symptoms before the prevention program. CONCLUSIONS: LISA-T is an effective school-based prevention program for eighth graders with minimal to mild depressive symptoms, but further research is needed.

Adolescent↗

PubMed2003

Simulation of Lamb wave propagation for the characterization of complex structures.

Reliable numerical simulation techniques represent a very valuable tool for analysis. For this purpose we investigated the applicability of the local interaction simulation approach (LISA) to the study of the propagation of Lamb waves in complex structures. The LISA allows very fast and flexible simulations, especially in conjunction with parallel processing, and it is particularly useful for complex (heterogeneous, anisotropic, attenuative, and/or nonlinear) media. We present simulations performed on a glass fiber reinforced plate, initially undamaged and then with a hole passing through its thickness (passing-by hole). In order to give a validation of the method, the results are compared with experimental data. Then we analyze the interaction of Lamb waves with notches, delaminations, and complex structures. In the first case the discontinuity due to a notch generates mode conversion, which may be used to predict the defect shape and size. In the case of a single delamination, the most striking "signature" is a time-shift delay, which may be observed in the temporal evolution of the signal recorded by a receiver. We also present some results obtained on a geometrically complex structure. Due to the inherent discontinuities, a wealth of propagation mechanisms are observed, which can be exploited for the purpose of quantitative nondestructive evaluation (NDE).

Algorithms↗

PubMed2006

Evaluation of eight commercial tests for Mycoplasma pneumoniae antibodies in the absence of acute infection.

Eight commercially available tests for Mycoplasma pneumoniae (Serodia-Myco II, Labsystems IgM and IgG EIA, IgM and IgG LISA tests, ImmunoWell IgG test and SeroMP IgM and IgG) were compared using 204 single sera from healthy individuals. IgM peaked in late childhood and then declined, while IgG rose progressively into adulthood. Inter-assay agreement was poor. Positivity in Serodia-Myco II and LISA IgG was associated with blood group or Coombs positivity, suggesting non-specific reactions. The study confirmed that single serum serology is unsuitable for the diagnosis of M. pneumoniae infection, and that commercially available tests need further improvement.

Adolescent↗

PubMed2000

Scattering of ultrasonic waves by void inclusions.

The Local Interaction Simulation Approach (LISA) has been applied to study the propagation of ultrasonic pulses in materials containing void inclusions. First the case of a single scatterer has been considered, with the conclusion that a void must be represented by at least four cells of the discretization lattice. Then the case of ultrasound propagation in a material with both a regular and random distribution of inclusions has been studied. Interesting interference effects have been obtained and it can be concluded that in both cases LISA allows reliable and efficient simulations to be performed.

Humans↗

PubMed1992

The expression of virulence genes in Listeria monocytogenes is thermoregulated.

The expression of listeriolysin, a major virulence factor of the gram-positive facultative intracellular pathogen Listeria monocytogenes, is positively regulated by a transcriptional activator, the prfA gene product. We had previously shown that mutations within the prfA gene lead to loss of listeriolysin production. In this communication, the regulation of expression of listeriolysin by a specific environmental condition, namely, temperature, was studied in wild-type strains of Listeria monocytogenes. We found that expression of the hemolysis phenotype was thermoregulated. A lisA::lacZ fusion was constructed, and its expression in the wild-type strain was studied at various growth temperatures. The results showed that the fusion beta-galactosidase activity was expressed only when cultures were grown at temperatures above 30 degrees C. This activity could be either specifically repressed or induced, depending on growth temperature. No change in activity was detected in a strain harboring a control beta-galactosidase fusion at the various growth temperatures tested. Northern (RNA) blot analysis of lisA-specific RNA transcripts showed that thermoregulation is manifested at the level of transcription. We also found that the transcription of other PrfA-regulated virulence genes in L. monocytogenes was similarly affected by growth temperature. Hence, as in other facultative intracellular pathogens, Shigella and Yersinia spp., temperature is an important cue in the induction of expression of virulence genes in L. monocytogenes. Our studies revealed that a higher level of regulation is imposed on the PrfA-mediated activation of virulence genes in pathogenic L. monocytogenes.

Bacterial Toxins↗

PubMed2006

[Maternal and child health indicators in Belo Horizonte, Minas Gerais State, Brazil, 2001: an analysis of intra-urban differences].

Spatial analysis of health indicators is as an important methodology for detection of intra-urban differences. This study aimed to examine the spatial distribution of all live births in Belo Horizonte, analyzing the presence of spatial clusters of health indicators for newborns and their mothers, using data from the Information System on Live Births. For each area covered by a Primary Health Care Unit, we calculated the indicators using empirical Bayesian methods. For spatial analysis, the indicators obtained from the global Moran (I) index and Local Indicators of Spatial Association (LISA) were used. Analysis using LISA showed the presence of relevant spatial clusters for adolescent mothers and those with low schooling, stillbirths in previous pregnancies, cesarean sections, and low attendance at prenatal care, especially in areas with low socio-demographic characteristics. The methodology adopted was configured as a key instrument for detecting risk areas where clustering occurs. The method can easily be incorporated into health surveillance systems as a mechanism for controlling events related to births in a given area.

Adolescent↗

PubMed2005

[Violence clusters in Pernambuco, Brazil].

OBJECTIVES: To analyze the spatial distribution of homicide mortality rates among males 15 to 49 years old in the state of Pernambuco, Brazil, for the periods of 1980 to 1984 and 1995 to 1998, and to identify violence clusters. METHODS: Mortality data were obtained from the Brazilian Ministry of Health's Mortality Information System. The mean homicide mortality rate was estimated for each municipality in the state for the two periods. The Moran coefficient was calculated to determine spatial autocorrelation. (The Moran coefficient ranges from -1 to +1, with a positive coefficient indicating a cluster of similar values, and a negative coefficient indicating adjacent dissimilar values.) To identify clusters of municipalities with either high or low homicide mortality rates, the local indicator of spatial association (LISA) was used. Finally, a Moran map was constructed to identify municipalities with statistically significant LISA values and to identify clusters of municipalities with either high or low homicide mortality rates. RESULTS: The Moran coefficient for 1980-1984 was 0.392, and for 1995-1998 it was 0.291 (P < 0.001). In the 1980-1984 period, one cluster of high homicide mortality rates was found in the Mata Sul region of the state, close to the metropolitan region of the state capital, Recife. In the 1995-1998 period, two violence clusters were identified: a predominantly urban one in the Recife metropolitan region, and the other in the state interior, in an area known as the "Marijuana Polygon" (Polígono da Maconha). CONCLUSION: This study suggests that the violence clusters are not the result of the socioeconomic conditions per se, but rather the consequence of the interaction between poor economic conditions and drug trafficking.

Adolescent↗

PubMed2006

Endocrinology and the skin.

CASE STUDY: 'I've got these ugly red blotches on my legs and they are getting worse?' Lisa, 32 years of age, is an accountant who always presents herself meticulously. You can understand why she doesn't like the raised red brown blotches on her shins. The lesions are raised, indurated with follicular accentuation. They are an uneven red-brown colour that doesn't fade with pressure, nor does the tissue pit. Lisa seems more upset and agitated than you expected. When you ask if she's under stress at work she breaks down in tears and says she feels 'agitated and on edge all the time and can't sit still for a minute'.

Adult↗

PubMed1993

A place to call home.

When 54 year old Lisa was admitted to the Western Division of the Toronto Hospital in November 1987, it was for removal of a benign cranio-cerebral tumor. The pulmonary compromise she had lived with for many years--the result of a congenitally short spine--was accentuated during the months following surgery. With breathing difficulties and recurrent pneumonia, Lisa required assisted ventilation. And though she tolerated being off the ventilator for a total of five hours during the day, repeated attempts to wean her were unsuccessful.

Brain Neoplasms↗