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1.
J Gen Virol ; 90(Pt 11): 2731-2738, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19625458

ABSTRACT

Although the Enders strain of mumps virus (MuV) encodes a functional V protein that acts as an interferon (IFN) antagonist, in multi-cycle growth assays MuV Enders grew poorly in naïve ('IFN-competent' Hep2) cells but grew to high titres in 'IFN-compromised' Hep2 cells. Even so, the growth rate of MuV Enders was significantly slower in 'IFN-compromised' Hep2 cells when compared with its replication rate in Vero cells and with the replication rate of parainfluenza virus type 5 (a closely related paramyxovirus) in both naïve and 'IFN-compromised' Hep2 cells. This suggests that a consequence of slower growth is that the IFN system of naïve Hep2 cells can respond quickly enough to control the growth of MuV Enders. This is supported by the finding that rapidly growing variants of MuV Enders that were selected on 'IFN-compromised' Hep2 cells (i.e. in the absence of any selection pressure exerted by the IFN response) also grew to high titres on naïve Hep2 cells. Sequencing of the complete genome of one of these variants identified a single point mutation that resulted in a substitution of a conserved asparagine by histidine at position 498 of the haemagglutinin-neuraminidase protein, although this mutation was not present in all rapidly growing variants. These results support the concept that there is a race between the ability of a cell to detect and respond to virus infection and the ability of a virus to block the IFN response. Importantly, this emphasizes that factors other than viral IFN antagonists influence the sensitivity of viruses to IFN.


Subject(s)
Interferons/antagonists & inhibitors , Interferons/immunology , Mumps virus/immunology , Mumps virus/physiology , Virus Replication , Amino Acid Substitution/genetics , Animals , Cell Line , Chlorocebus aethiops , DNA Mutational Analysis , HN Protein/genetics , Humans , Mutation, Missense , Viral Plaque Assay
2.
Comput Biol Med ; 39(4): 396-403, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19268924

ABSTRACT

Searching biomedical information in a large collection of medical data is a complex task. The use of tools and biomedical resources could ease the retrieval of the information desired. In this paper, we use the medical ontology MeSH to improve a Multimodal Information Retrieval System by expanding the user's query with medical terms. In order to accomplish our experiments, we have used the dataset provided by ImageCLEFmed task organizers for years 2005 and 2006. This dataset is composed of a multimodal collection (images and text) of clinical cases, a list of queries for each year, and a list of relevance judgments for each query to evaluate the results. The results from the experiments show that the use of a medical ontology to expand the queries greatly improves the results.


Subject(s)
Informatics/methods , Information Storage and Retrieval , Algorithms , Artificial Intelligence , Computer Graphics , Database Management Systems , Databases, Bibliographic , Decision Support Systems, Clinical , Humans , Natural Language Processing , Pattern Recognition, Automated , Software , User-Computer Interface , Vocabulary, Controlled
3.
Medicina (B Aires) ; 61(6): 825-9, 2001.
Article in Spanish | MEDLINE | ID: mdl-11808422

ABSTRACT

In immunocompromised patients, diagnosis of Cytomegalovirus (CMV) active infection is of utmost importance for the initiation, monitoring and ending of antiviral therapy. Therefore, the presence of viral replication should be demonstrated. Isolation in tissue culture is one of the standard methods. The objective of the present paper was to compare two isolation procedures for CMV: conventional cell culture (CC) and rapid shell vial (SV) assay in human fibroblasts. A total of 584 clinical samples were studied between 1991 and 1998. CMV was isolated in 14.4% of the samples, 11.8% of which were positive by SV and 7.7% by CC. Out of 84 positive samples, concordance between both methods was observed in 36% of the cases. We found that 46% of the samples were positive only by SV, while 18% were positive only by CC. The average time required for obtaining the results by CC was 22.6 +/- 2.3 days. Out of the 69 samples positive by SV, 43% were already positive after 24 hours and the rest after 48 hours. These results indicate that SV was more sensitive and rapid than CC. The main advantage of CC, despite its time-consuming process, is the ability to recover the viral strain for both antiviral susceptibility phenotypical tests and strain characterization. Furthermore, in this study, absence of CC would have resulted in the loss of 18% of the positive diagnoses. In conclusion, simultaneous use of both methods is suggested in order to obtain a rapid result and the highest sensitivity.


Subject(s)
Cytomegalovirus Infections/diagnosis , Cytomegalovirus/isolation & purification , Humans , Sensitivity and Specificity , Virus Cultivation/methods , Virus Replication
4.
Medicina [B Aires] ; 61(6): 825-9, 2001.
Article in Spanish | BINACIS | ID: bin-39365

ABSTRACT

In immunocompromised patients, diagnosis of Cytomegalovirus (CMV) active infection is of utmost importance for the initiation, monitoring and ending of antiviral therapy. Therefore, the presence of viral replication should be demonstrated. Isolation in tissue culture is one of the standard methods. The objective of the present paper was to compare two isolation procedures for CMV: conventional cell culture (CC) and rapid shell vial (SV) assay in human fibroblasts. A total of 584 clinical samples were studied between 1991 and 1998. CMV was isolated in 14.4


of the samples, 11.8


of which were positive by SV and 7.7


by CC. Out of 84 positive samples, concordance between both methods was observed in 36


of the cases. We found that 46


of the samples were positive only by SV, while 18


were positive only by CC. The average time required for obtaining the results by CC was 22.6 +/- 2.3 days. Out of the 69 samples positive by SV, 43


were already positive after 24 hours and the rest after 48 hours. These results indicate that SV was more sensitive and rapid than CC. The main advantage of CC, despite its time-consuming process, is the ability to recover the viral strain for both antiviral susceptibility phenotypical tests and strain characterization. Furthermore, in this study, absence of CC would have resulted in the loss of 18


of the positive diagnoses. In conclusion, simultaneous use of both methods is suggested in order to obtain a rapid result and the highest sensitivity.

5.
Eur J Nucl Med ; 22(11): 1274-7, 1995 Nov.
Article in English | MEDLINE | ID: mdl-8575476

ABSTRACT

The objective of this study was to search for regional cerebral blood flow (rCBF) abnormalities in adolescents with initial-stage schizophrenia by means of brain single-photon emission tomography (SPET) using technetium-99m hexamethylpropylene amine oxime (HMPAO). SPET studies were performed on a homogeneous sample of 15 carefully selected adolescents with a recent diagnosis of schizophrenia, and without previous electroconvulsive or antipsychotic drug treatment. Computed tomography (CT) and electro-encephalographic (EEG) studies were performed in all patients. Qualitative and semiquantitative analysis of 99mTc-HMPAO SPET studies showed an impaired rCBF in 12 patients (80%). The most common pattern was a decreased uptake of 99mTc-HMPAO in the frontal lobes, usually in the left hemisphere. Conventional and quantitative EEG was positive in 12 (80%) and 15 (100%) patients, respectively. CT findings were positive in two patients (13%). There was a high level of concordance between SPET and EEG results and between SPET and clinical features (P>0.05). This study suggests that previously untreated patients in the first stages of schizophrenia present functional abnormalities that are revealed by brain SPET.


Subject(s)
Brain/diagnostic imaging , Organotechnetium Compounds , Oximes , Schizophrenia/diagnostic imaging , Tomography, Emission-Computed, Single-Photon , Adolescent , Cerebrovascular Circulation , Electroencephalography , Female , Humans , Male , Schizophrenia/physiopathology , Technetium Tc 99m Exametazime , Tomography, X-Ray Computed
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