RESUMEN
OBJECTIVE: To assess the agreement of different diagnostic methods for the diagnosis and confirmation of the clinical suspicion of Plasmodium infection in children in Tanzania and Kenya. METHOD: Blood samples were collected by the finger prick method from 338 children. Blood samples were collected from 338 children with the clinical suspicion of uncomplicated malaria in health clinics in Tanzania and Kenya. The presence of Plasmodium parasites was assessed with microscopy, rapid diagnostic tests (RDTs) and the molecular assays, quantitative nucleic acid sequence based amplification (QT-NASBA) and polymerase chain reaction (PCR). The results were compared and analysed for agreement. RESULTS: There was a high degree of agreement (88.6-100%) between RDTs or molecular tests and microscopy. In rural Kenya, with a high incidence of malaria cases, the correlation coefficient ranged from 0.94 for RDTs to 0.76 for PCR. In urban Tanzania, where there was a low incidence of cases, R for RDTs was 1.0 but only 0.25 for PCR and 0.33 for NASBA. CONCLUSION: Malaria is overestimated if the diagnosis is based solely on clinical signs. Therefore, laboratory confirmation is essential. Microscopy is a reliable method in rural areas where malaria is prevalent, but RDTs offer a good alternative with the advantage that it is an easy and rapid method. Molecular tests are more sensitive but difficult to implement in rural areas. In areas with lower incidence, molecular tests detect a significantly higher number of Plasmodium infections than RDTs or microscopy. Although implementation of molecular tools can be difficult, the prospect of an easy and cheap detection system makes them promising tools for the near future.
Asunto(s)
Antígenos de Protozoos/análisis , Malaria/diagnóstico , Niño , Preescolar , Pruebas Diagnósticas de Rutina/métodos , Femenino , Humanos , Incidencia , Lactante , Kenia/epidemiología , Malaria/epidemiología , Malaria/parasitología , Malaria Falciparum/diagnóstico , Malaria Falciparum/epidemiología , Malaria Falciparum/parasitología , Masculino , Microscopía/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Recuento de Huevos de Parásitos , Reacción en Cadena de la Polimerasa/métodos , Estudios Prospectivos , Salud Rural , Tanzanía/epidemiología , Salud UrbanaRESUMEN
Deletions in the short arm of chromosome 1 (1p36) and MYCN amplification are common in neuroblastoma. Previously we showed evidence of at least two different neuroblastoma tumor-suppressor loci on 1p. One is associated with MYCN single-copy tumors and maps distal on 1p36.3. A second, more proximal locus maps to 1p36.1 and is deleted in about 90% of neuroblastomas with MYCN amplification. The cell line UHG-NP has the smallest 1p36 deletion of all neuroblastoma cell lines with MYCN amplifications. We assume that the more proximal locus maps within this deletion, close to its proximal border. Here we present the exact localization of the 1p deletion breakpoint of UHG-NP. A 600-kb PAC contig spanning the breakpoint was analyzed for genes and aberrations. Two more neuroblastoma-associated aberrations were mapped within 150 kb of the UHG-NP breakpoint. Within the contig, we identified nine genes expressed in neuroblastoma cells. One of these genes, AML2, maps 200 kb distal to the UHG-NP breakpoint but is expressed only rarely in neuroblastoma and showed no mutations.
Asunto(s)
Aberraciones Cromosómicas/genética , Cromosomas Humanos Par 1/genética , Neuroblastoma/genética , Composición de Base , Southern Blotting , Rotura Cromosómica/genética , Deleción Cromosómica , ADN de Neoplasias/análisis , Duplicación de Gen , Genes myc/genética , Humanos , Familia de Multigenes/genética , Células Tumorales CultivadasRESUMEN
Neuroblastoma is an embryonal tumor originating from neural crest-derived cells. Here we present the serendipitous cloning of amplified sequences of chromosome 2p15 in neuroblastoma cell line IMR32. The amplified region was analyzed for oncogene activation using a SAGE (serial analysis of gene expression) library of IMR32. SAGE permits a quantitative analysis of all transcripts of a tissue or cell line. The expression of genes and ESTs mapping within a 30-cR region covering the amplicon was compared to 4 additional SAGE libraries of neuroblastomas and 12 SAGE libraries of other tissues in the CGAP databases. The IMR32 SAGE database revealed increased expression of the MEIS1 oncogene, whereas other SAGE libraries showed little or no MEIS1 expression. MEIS1 turned out to be highly amplified and overexpressed in IMR32. Analysis of 24 neuroblastoma cell lines and 22 tumors showed high-level expression in about 25% of the cases. The MEIS1 homeobox protein forms a complex with the HOXA9 and PBX proteins that are implicated in human leukemia. MEIS1 is a target of retroviral insertion in murine leukemia. This is the first report of a MEIS1 amplification and high expression levels in human cancer and the first time that identification of a candidate target of amplification is facilitated by high-throughput mRNA expression profiling.
Asunto(s)
Proteínas de Homeodominio/genética , Proteínas de Neoplasias/genética , Neuroblastoma/metabolismo , Células Tumorales Cultivadas/metabolismo , Northern Blotting , Cromosomas Humanos Par 2/genética , Clonación Molecular , Perfilación de la Expresión Génica , Biblioteca de Genes , Humanos , Datos de Secuencia Molecular , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide , Neuroblastoma/etiología , Neuroblastoma/patología , Oncogenes/genética , Mapeo de Híbrido por Radiación , Análisis de Secuencia de ADNRESUMEN
A previous loss of heterozygosity (LOH) study of a series of 91 neuroblastomas suggested that the 1p35-36 region encodes at least two tumor suppressor genes (TSGs) of importance in neuroblastoma development. Here we present the results of a study including 205 neuroblastomas that were analyzed for LOH at chromosome 1 and MYCN amplification. The results corroborate the existence of two TSGs on 1p. Distinct 1p loci seem to be involved in MYCN single copy vs. MYCN amplified neuroblastoma, as these tumors display a different type of shortest region of overlap (SRO). About 15% of MYCN single copy neuroblastomas show 1p deletions of variable length with an SRO of 47 cR at 1p36.3. The lost alleles are preferentially of maternal origin (P = 0.0002), suggesting parental imprinting of the locus. MYCN amplified neuroblastomas have a contrasting pattern of 1p loss. These tumors display much larger deletions of at least 89 cR comprising the region from 1p36.1 to the telomere. LOH of 1p is detected in 86% of the cases. The lost alleles are of random parental origin, suggesting inactivation of a non-imprinted TSG.
Asunto(s)
Cromosomas Humanos Par 1/genética , Genes Supresores de Tumor/genética , Impresión Genómica/genética , Neuroblastoma/genética , Bandeo Cromosómico , Femenino , Amplificación de Genes/genética , Eliminación de Gen , Dosificación de Gen , Genes myc/genética , Humanos , Pérdida de Heterocigocidad/genética , MasculinoRESUMEN
Common genetic aberrations of neuroblastoma are deletions of the short arm of chromosome 1 (1p36) and MYCN amplification. Our deletion analysis of 25 tumor cell lines and 171 tumors strongly suggests that 1p harbors several tumor suppressor loci. Distinct loci are involved in MYCN single-copy versus MYCN-amplified neuroblastoma. Deletions in MYCN single-copy tumors have a shortest region of overlap (SRO) of 20 cM at 1p36.3. MYCN-amplified tumors have large deletions with an SRO of about 60 cM, from 1p36.1 to the telomere. This SRO is defined by D1S7 (1p36.1), which was the most distal locus retained. Therefore, a suppressor gene associated with MYCN-amplified tumors probably maps within a few megabases distal of D1S7. In order to map this locus, we further refined this SRO. We mapped the breakpoint of the MYCN-amplified neuroblastoma with the smallest 1p deletion between 56.6 and 57.2 cM from 1pter. Pulsed-field gel electrophoresis and radiation hybrid mapping were used to construct a 5-Mb physical map of this region. The map includes the region from 82.73 till 92.89 cR from 1pter. About half of it was isolated in P1 and PAC clones. The region harbors the genes FGR, SLC9A1, HMG17, EXTL1, AML2, RH, OP18, four ESTs, and a newly identified gene with a transcript size of approximately 7 Kb. Several of the mapped genes have a putative role in cell growth, differentiation, and morphogenesis. Genes Chromosomes Cancer 27:143-152, 2000.
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Cromosomas Humanos Par 1/genética , Neuroblastoma/genética , Mapeo Físico de Cromosoma , Bacteriófago P1 , Mapeo Contig , Electroforesis en Gel de Campo Pulsado , Etiquetas de Secuencia Expresada , Amplificación de Genes , Genes/genética , Genes myc/genética , Marcadores Genéticos , Vectores Genéticos , Humanos , Células Híbridas , Datos de Secuencia Molecular , Neuroblastoma/etiología , Células Tumorales CultivadasRESUMEN
Recently, the EXTL1 gene, a member of the EXT tumor suppressor gene family, has been mapped to 1p36, a chromosome region which is frequently implicated in a wide variety of malignancies, including breast carcinoma, colorectal cancer and neuroblastoma. In this study, we show that the EXTL1 gene is located between the genetic markers D1S511 and D1S234 within 200 kb of the LAP18 gene on chromosome 1p36. 1, a region which has been proposed to harbor a tumor suppressor gene implicated in MYCN-amplified neuroblastomas. In addition, we determined the genomic structure of the EXTL1 gene, revealing that the EXTL1 coding sequence spans 11 exons within a 50-kb region.
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Cromosomas Humanos Par 1 , N-Acetilglucosaminiltransferasas , N-Acetilhexosaminiltransferasas/genética , Proteínas Supresoras de Tumor , Neoplasias de la Mama/genética , Línea Celular , Mapeo Cromosómico , Neoplasias Colorrectales/genética , Exones , Femenino , Marcadores Genéticos , Humanos , Hibridación Fluorescente in Situ , Linfocitos/citología , Neuroblastoma/genética , Sistemas de Lectura AbiertaAsunto(s)
Cromosomas Humanos Par 1/genética , Mapeo Físico de Cromosoma , Animales , Aberraciones Cromosómicas/genética , Biología Computacional , Secuencia Conservada/genética , Evolución Molecular , Enfermedades Genéticas Congénitas/genética , Humanos , Internet , Ratones , Neoplasias/genética , Análisis de Secuencia de ADNRESUMEN
In this paper, the pattern of induction of heat shock proteins (hsps) was studied in cultured Reuber H35 rat hepatoma cells by sequential application of different stressors. We analyzed whether a specific stress condition is able to induce an enhanced sensitivity to a subsequent application of a low dose of either the same or another stressor (self-sensitization and cross-sensitization, respectively). As a measure of sensitization, the stimulation of hsp induction was employed. Three different stressor conditions (heat shock, sodium arsenite and cadmium chloride) were used in doses which exerted a similar impact on overall protein synthesis. A synergistic effect in induction of the synthesis of various hsps was observed when a high stressor dose was followed by an 8-h incubation in a lower stressor dose in both self- and cross-sensitization experiments. The low-dose conditions used as second treatments did not induce any responses in non-pretreated cells. Studies in cultured cells have demonstrated stressor-specific hsp induction patterns. In this study we analyzed whether the pattern of hsps induced by the low-dose condition is characteristic for the first sensitizing stressor or for the secondary stressor applied in a low dose. The pattern of hsps which was induced above the level of the high-dose effect, due to the incubation with the secondary applied low-dose condition, was found to be characteristic for the secondary stressor and not for the sensitizing primary treatment. These results are of importance for an improved understanding of the regulation of heat shock protein synthesis in conditions of self- and cross-sensitization, as well as for a proper use of hsps as biomarkers of exposure to environmental stress.
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Arsenitos/toxicidad , Cloruro de Cadmio/toxicidad , Carcinógenos/toxicidad , Inhibidores Enzimáticos/toxicidad , Proteínas de Choque Térmico/biosíntesis , Calor , Compuestos de Sodio/toxicidad , Animales , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Electroforesis en Gel de Poliacrilamida , Neoplasias Hepáticas Experimentales , Ratas , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/metabolismoRESUMEN
The existence of stressor-specific induction programs of heat shock proteins (hsps) leads us to analyze the possible occurrence of a stressor-specific tolerance induced by either heat shock, arsenite, or cadmium. As a measure of this tolerance re-induction of hsps was studied. In this paper, we tested whether the refractory state is either valid for each specific hsp (implying independent regulation of every member of the heat shock protein family) or extends from small subsets of the hsp-family to even larger groups of proteins (indicating a more common denominator in their regulation). (re-)induction of hsps does not seem to be regulated at the level of each individual hsp since differences in induced synthesis of hsps between two stressor conditions are not supplemented systematically upon the sequential application of the two stressors. The most notable example in this respect is hsp60. A pretreatment with cadmium, which hardly induces synthesis of this hsp, does induce a tolerance to (re)-induction by heat shock, which normally induces hsp60. This suggests the existence of a more common denominator regulating the coordinate expression of at least some hsps. From our data we conclude that the degree, but not the pattern, of hsp re-induction is influenced by the type of stressor used in the pretreatment. The pattern of hsps induced by a secondary applied stressor still shows most of its stressor-specificity and seems to be independent of any pretreatment. The possible implications of stressor-specificity are discussed.
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Regulación de la Expresión Génica/genética , Proteínas de Choque Térmico/metabolismo , Estrés Fisiológico , Animales , Arsenitos/farmacología , Cloruro de Cadmio/farmacología , Electroforesis en Gel de Poliacrilamida , Cinética , Hígado/metabolismo , Ratas , Compuestos de Sodio/farmacología , Temperatura , Células Tumorales CultivadasRESUMEN
E-cadherin is considered to be an invasion suppressor molecule. We have studied the expression and function of E-cadherin in three cell lines derived from a dog mammary tumor, namely SH15, SH24, and SH27. In monolayer culture the cell lines can be distinguished by their morphotype: epithelioid (SH15), fibroblast-like (SH24) and intermediate type (SH27). SH27 was unable to form colonies in collagen gel in contrast to SH15 and SH24. All three cell lines expressed the E-cadherin antigen, as evident from immunocytochemistry, and alpha-, beta-, and gamma-catenins as evident from immunoprecipitation with E-cadherin antibody. Only SH27 showed E-cadherin-dependent aggregation, and little invasion into collagen type 1 gels, in contrast to SH15 and SH24 cells. However, in the precultured embryonic chick heart assay all three cell lines were invasive, demonstrating that invasion depends upon the microenvironment. We assume that in the embryonic chick heart, factors were present or were induced by the SH27 cells, interfering with the function of E-cadherin.