RESUMEN
Numerous medical on-line services have already been established in the world-wide internet. In connection with the Information service TELESCAN, sponsored by the EU, a pilot project has been initiated which offers a radiological "second opinion" via the transmission of radiological findings and images that have been previously rendered anonymous. In addition to a description of the basic implementation, tests of the diagnostic certainty of the transmitted cranial computed tomographs have been performed. The CT images were digitized with a document camera, transmitted over the Internet, and then evaluated on the receiver's monitor. Both the transfer of originally generated digital image files (in ACR-NEMA or DICOM) as well as graphic files after digitization of X-ray films, for example by a document camera, is possible via electronic post (e-mail). Visualization by the receiver requires the use of current proprietary software for special medical image formats, while standard graphic formats such as GIFF or JPEG can be visualized with the usual Internet software. In an ROC analysis, 56 individual images of cranial computed tomographs, half with pathological findings such as space-occupying lesions, infarcts, or brain edema, were tested with regard to the diagnostic certainty after digitization and transmission. In comparison with the original film findings, there was a slight but statistically not significant reduction in diagnostic certainty of the images evaluated on screen after transfer via the Internet. We believe that this result is due to the low local resolution, low dynamic range, the high image noise and of CT arising from the window technique. The same parameters are probably valid for MRI. The result cannot be applied to conventional radiography including mammography because, in comparison to the mentioned image techniques, their local resolution is high and image noise is considerably lower.
Asunto(s)
Redes de Comunicación de Computadores/instrumentación , Derivación y Consulta , Telerradiología/instrumentación , Sistemas de Computación , Humanos , Reproducibilidad de los Resultados , Programas Informáticos , Tomografía Computarizada por Rayos X/instrumentaciónRESUMEN
A generalised registration-randomisation package, known as paradigm, has been developed by the Netherlands Cancer Institute and the MRC Cancer Trials Office initiated in association with the EORTC within the EuroCODE project and partially funded by the European Community. This randomisation software takes into account requirements of four major data centres in Belgium, France, The Netherlands and the UK and is suitable for use at further European Clinical Trial data centres to enable remote entry of patients into trials. The system became operational at the start of 1994, and is now in use at three hospitals and data centres.
Asunto(s)
Ensayos Clínicos Controlados Aleatorios como Asunto , Programas Informáticos , Interpretación Estadística de Datos , Unión Europea , Humanos , Selección de Paciente , Garantía de la Calidad de Atención de Salud , Proyectos de InvestigaciónRESUMEN
We have reported the generation and characterization of four HIV-1 neutralizing human monoclonal antibodies. Three antibodies recognize a conformational epitope within the CD4-binding site of HIV-1 gp120 and one recognizes a linear epitope located within the hypervariable V3 domain of gp120. In the present study we report the nucleotide sequences of the cDNAs encoding the variable regions of the heavy and light chains of these antibodies. Molecular characteristics, closet germline genes, and the putative extent of somatic mutation are presented. Two of the four heavy chain variable (VH) regions are derived from the VH1 gene family, one from the VH3 gene family, and one from the VH5 gene family. In addition, the VH chain of a previously described human monoclonal antibody, directed against HIV-1 gp41, is derived from the VH3 gene family. The degree of nucleotide variation between these five antibodies and their closest germline counterparts ranges from 4 to 12%, mainly located in the complementarity-determining regions. Significant nucleotide sequence homology with previously described germline diversity (D) genes could be found for only two of five antibody D segments. Joining (JH) gene segments utilized are JH4 or JH6. Two light chain variable (VL) regions are derived from a VK1 gene segment, one from a V kappa 4, one from a V lambda 2, and one from a lambda 6 gene segment.
Asunto(s)
Anticuerpos Monoclonales/genética , Anticuerpos Anti-VIH/genética , Cadenas Pesadas de Inmunoglobulina/genética , Cadenas Ligeras de Inmunoglobulina/genética , Región Variable de Inmunoglobulina/genética , Secuencia de Aminoácidos , Anticuerpos Monoclonales/inmunología , Linfocitos B/inmunología , Secuencia de Bases , ADN Complementario , Anticuerpos Anti-VIH/inmunología , Proteína gp120 de Envoltorio del VIH/inmunología , Seropositividad para VIH/inmunología , Humanos , Región de Unión de la Inmunoglobulina/genética , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido NucleicoRESUMEN
BACKGROUND: In allergic and nonallergic asthma, eosinophils play an important effector role. However, because the pathogenesis of these types of asthma seems different, the mechanisms responsible for the tissue mobilization of those cells may be different. The in vivo and in vitro migratory response of eosinophils from patients with allergic and nonallergic asthma toward 20-hydroxy-leukotriene B4 (20-OH-LTB4), which is reported here, illustrates this. METHODS: By means of the Rebuck skin window technique the in vivo skin mobilizing capacity of intracutaneously applied buffer, LTB4, and 20-hydroxy (OH)-LTB4 was evaluated in healthy subjects (n = 6), subjects with allergic asthma (n = 14), and subjects with nonallergic asthma (n = 17). Also the in vitro chemotactic responsiveness of eosinophils from the circulation of both patient groups (both n = 8) toward buffer, LTB4, and 20-OH-LTB4 were tested by use of a microchemotaxis chamber technique. RESULTS: Although none of the substances were capable of inducing macroscopic observable skin reactions, intracutaneously applied 20-OH-LTB4 had an almost similar capacity to mobilize eosinophils in the skin of the subjects with nonallergic asthma as allergens had in subjects with allergic asthma. In 92% of the tested subjects with nonallergic asthma significant skin eosinophilia was observed. By contrast, LTB4 did not induce significant skin eosinophilia in both patient groups compared with buffer solution. This in vivo eosinophil mobilizing capacity of 20-OH-LTB4 in subjects with nonallergic asthma was confirmed by in vitro chemotaxis studies. Dose ranges of both LTB4 and 20-OH-LTB4 proved to be potent chemoattractants for eosinophils from patients with nonallergic asthma, but not for those of healthy subjects and those with allergic asthma. CONCLUSIONS: Our results indicate that 20-OH-LTB4 may be involved in the tissue mobilization of eosinophils in nonallergic asthma and that in vitro 20-OH-LTB4 (and LTB4) may act as potent chemotactic factors on eosinophils from those patients.
Asunto(s)
Asma/patología , Eosinófilos/patología , Hipersensibilidad/patología , Piel/patología , Adulto , Asma/etiología , Quimiotaxis de Leucocito/efectos de los fármacos , Eosinófilos/efectos de los fármacos , Femenino , Humanos , Hipersensibilidad/complicaciones , Leucotrieno B4/farmacología , Masculino , Valores de Referencia , Técnica de Ventana CutáneaRESUMEN
Rat basophilic leukemia cells exhibit 12-lipoxygenase activity only upon cell disruption. 12-Lipoxygenase may also possess 15-lipoxygenase activity, as is indicated by the formation of low amounts of 15(S)-HETE, in addition to the predominant product 12(S)-HETE, upon incubation of partially purified 12-lipoxygenase with arachidonic acid. With 5(S)-HPETE as substrate not only 5(S), 12(S)-diHETE and 5(S), 15(S)-diHETE are formed, but also LTA4, as was indicated by the presence of LTA4-derived LTB4-isomers. 12-Lipoxygenase from rat basophilic leukemia cells has many features in common with 12-lipoxygenase from bovine leukocytes. As was suggested for the latter enzyme, 12-lipoxygenase from rat basophilic leukemia cells may represent the remaining LTA4-synthase activity of 5-lipoxygenase, of which the 5-dioxygenase activity has disappeared upon cell disruption. Such a possible shift from 5-lipoxygenase activity to 12-lipoxygenase activity could not simply be induced by interaction of cytosolic 5-lipoxygenase with a membrane fraction after cell disruption, but may involve release of membrane-associated 5-lipoxygenase upon disruption of activated rat basophilic leukemia cells.
Asunto(s)
Araquidonato 12-Lipooxigenasa/metabolismo , Araquidonato 5-Lipooxigenasa/metabolismo , Leucemia Basofílica Aguda/enzimología , Animales , Araquidonato 12-Lipooxigenasa/aislamiento & purificación , Araquidonato 5-Lipooxigenasa/aislamiento & purificación , Fraccionamiento Celular , Cromatografía Líquida de Alta Presión , Citosol/enzimología , Ácidos Hidroxieicosatetraenoicos/aislamiento & purificación , Ácidos Hidroxieicosatetraenoicos/metabolismo , Cinética , Ratas , Células Tumorales CultivadasRESUMEN
Numbers of circulating basophils are increased in asthmatic subjects, compared to normal subjects. Basophil enriched cell preparations from normal and asthmatic subjects were challenged in vitro with the calcium ionophore A23187, anti-IgE, or opsonized zymosan to study leukotriene C4 formation, histamine release, and prostaglandin D2 formation. No prostaglandin D2 formation by basophils was observed. Furthermore, opsonized zymosan was not capable of inducing any mediator formation or release from basophils. At optimal stimulation conditions no differences were found between basophils from normal and asthmatic subjects concerning A23187 or anti-IgE induced leukotriene C4 formation or histamine release. A23187 and anti-IgE induced leukotriene C4 formation were in the range of 1-20 and 0.6-4.8 pmol/10(6) basophils respectively.
Asunto(s)
Asma/sangre , Basófilos/metabolismo , SRS-A/biosíntesis , Anticuerpos Antiidiotipos/fisiología , Asma/inmunología , Basófilos/efectos de los fármacos , Calcimicina/farmacología , Liberación de Histamina , Humanos , Inmunoglobulina E/inmunología , Inmunoglobulina E/fisiología , Proteínas Opsoninas , Prostaglandina D2/biosíntesis , SRS-A/sangre , ZimosanRESUMEN
12-Lipoxygenase from rat basophilic leukemia cells was purified about 300-fold by protein-HPLC in a single run. Maximal 12-lipoxygenase activity was observed at pH 7.5, while the enzyme became almost inactive at pH 6 and 9. Although Ca2+ was not essential for 12-lipoxygenase activity, the partially purified enzyme was stimulated approx. 2-fold in the presence of 0.1-5.0 mM Ca2+. Contrary to 5-lipoxygenase from RBL-1 cells, 12-lipoxygenase was not inactivated by preincubation with Ca2+ for 1-10 min, nor was it stimulated by 0.1-10 mM ATP.
Asunto(s)
Araquidonato 12-Lipooxigenasa/aislamiento & purificación , Leucemia Basofílica Aguda/enzimología , Animales , Araquidonato 12-Lipooxigenasa/metabolismo , Araquidonato 5-Lipooxigenasa/metabolismo , Calcio/metabolismo , Cromatografía Líquida de Alta Presión , Concentración de Iones de Hidrógeno , Inhibidores de la Lipooxigenasa , Ratas , Células Tumorales Cultivadas/enzimologíaRESUMEN
12-Lipoxygenase and 5-lipoxygenase from rat basophilic leukemia cells were separated by protein-HPLC in a single step. Upon incubation in the presence of Ca2+, 12-lipoxygenase converted arachidonic acid into 12(S)-hydroxyeicosatetraenoic acid and linoleic acid into 13(S)-hydro(pero)xyoctadecadienoic acid. The reaction products were analyzed by reversed-phase and chiral straight-phase HPLC with ultraviolet-detection. Using the cytosolic fraction of rat basophilic leukemia cells, optimal 12-lipoxygenase activity was observed at 10 degrees C. At 37 degrees C 12-lipoxygenase was very rapidly inactivated by its own product, hydroperoxy fatty acid, at low concentrations (10-100 nM).
Asunto(s)
Araquidonato 12-Lipooxigenasa/metabolismo , Leucemia Experimental/enzimología , Animales , Araquidonato 12-Lipooxigenasa/aislamiento & purificación , Ácido Araquidónico , Ácidos Araquidónicos/metabolismo , Cromatografía DEAE-Celulosa , Cromatografía en Gel , Ácidos Grasos/metabolismo , Ratas , Temperatura , Células Tumorales CultivadasRESUMEN
The presence of Fc receptors for IgE on epidermal Langerhans cells (LC) from patients with atopic dermatitis (AD) was demonstrated by three different types of experiments. Firstly, cell-bound IgE on LC was removed by acid elution and restored by highly purified human myeloma IgE (IgE kappa). Secondly, after pepsin digestion of cell-bound IgE the number of LC staining with anti-human light chain (kappa, lambda) antibodies significantly decreased in contrast to the number of LC staining with anti-human epsilon heavy chain antibody. Thirdly, LC formed rosettes with sheep red blood cells (SRBC) coated with IgE kappa. Epidermal LC from normal non-atopic controls, did not form rosettes with SRBC-IgE. The SRBC-IgE rosette formation could be inhibited by preincubation with IgE kappa and BB10 (MoAb directed against the Fc receptor for IgE on human eosinophils, platelets and macrophages), but also with human IgG, whereas the SRBC-IgG rosette formation could be inhibited neither by IgE kappa nor by BB10. Both the SRBC-IgE and the SRBC-IgG rosette formation could be inhibited by OKT6 (anti-CD1) antibody. The results of inhibition studies with OKT6 antibody on the reconstitution of IgE on epidermal LC after acid elution suggest an associated expression of the CD1 antigen and the Fc receptor for IgE.
Asunto(s)
Antígenos de Diferenciación de Linfocitos B/análisis , Dermatitis Atópica/inmunología , Inmunoglobulina E/inmunología , Células de Langerhans/inmunología , Receptores Fc/análisis , Antígenos de Diferenciación/análisis , Antígenos de Superficie/análisis , Humanos , Inmunoglobulina G/inmunología , Receptores de IgE , Formación de RosetaRESUMEN
A combination of non-interactive statistical methods is discussed to analyze multiparametric light-scatter data obtained by means of computer-assisted centrifugal elutriation.