Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
Environ Pollut ; 349: 123844, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38580065

RESUMEN

Increasing nitrogen depositions adversely affect European landscapes, including habitats within the Natura2000 network. Critical loads for nitrogen deposition have been established to quantify the loss of habitat quality. When the nitrogen deposition rises above a habitat-specific critical load, the quality of the focal habitat is expected to be negatively influenced. Here, we investigate how the quality of habitat types is affected beyond the critical load. We calculated response curves for 60 terrestrial habitat types in the Netherlands to the estimated nitrogen deposition (EMEP-data). The curves for habitat types are based on the occurrence of their characteristic plant species in North-Western Europe (plot data from the European Vegetation Archive). The estimated response curves were corrected for soil type, mean annual temperature and annual precipitation. Evaluation was carried out by expert judgement, and by comparison with gradient deposition field studies. For 39 habitats the response to nitrogen deposition was judged to be reliable by five experts, while out of the 41 habitat types for which field studies were available, 25 showed a good agreement. Some of the curves showed a steep decline in quality and some a more gradual decline with increasing nitrogen deposition. We compared the response curves with both the empirical and modelled critical loads. For 41 curves, we found a decline already starting below the critical load.


Asunto(s)
Ecosistema , Monitoreo del Ambiente , Nitrógeno , Nitrógeno/análisis , Monitoreo del Ambiente/métodos , Países Bajos , Suelo/química , Plantas/metabolismo
3.
Leukemia ; 31(11): 2398-2406, 2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-28804124

RESUMEN

Chronic myeloid leukemia (CML)-study IV was designed to explore whether treatment with imatinib (IM) at 400 mg/day (n=400) could be optimized by doubling the dose (n=420), adding interferon (IFN) (n=430) or cytarabine (n=158) or using IM after IFN-failure (n=128). From July 2002 to March 2012, 1551 newly diagnosed patients in chronic phase were randomized into a 5-arm study. The study was powered to detect a survival difference of 5% at 5 years. After a median observation time of 9.5 years, 10-year overall survival was 82%, 10-year progression-free survival was 80% and 10-year relative survival was 92%. Survival between IM400 mg and any experimental arm was not different. In a multivariate analysis, risk group, major-route chromosomal aberrations, comorbidities, smoking and treatment center (academic vs other) influenced survival significantly, but not any form of treatment optimization. Patients reaching the molecular response milestones at 3, 6 and 12 months had a significant survival advantage. For responders, monotherapy with IM400 mg provides a close to normal life expectancy independent of the time to response. Survival is more determined by patients' and disease factors than by initial treatment selection. Although improvements are also needed for refractory disease, more life-time can currently be gained by carefully addressing non-CML determinants of survival.


Asunto(s)
Antineoplásicos/uso terapéutico , Mesilato de Imatinib/uso terapéutico , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Análisis de Supervivencia , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Relación Dosis-Respuesta a Droga , Femenino , Trasplante de Células Madre Hematopoyéticas , Humanos , Leucemia Mielógena Crónica BCR-ABL Positiva/terapia , Masculino , Persona de Mediana Edad , Adulto Joven
4.
Leukemia ; 31(4): 829-836, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-28074067

RESUMEN

It is unknown, why only a minority of chronic myeloid leukemia (CML) patients sustains treatment free remission (TFR) after discontinuation of tyrosine kinase inhibitor (TKI) therapy in deep molecular remission (MR). Here we studied, whether expression of the T-cell inhibitory receptor (CTLA-4)-ligand CD86 (B7.2) on plasmacytoid dendritic cells (pDC) affects relapse risk after TKI cessation. CML patients in MR displayed significantly higher CD86+pDC frequencies than normal donors (P<0.0024), whereas TFR patients had consistently low CD86+pDC (n=12). This suggested that low CD86+pDC might be predictive of TFR. Indeed, in a prospective analysis of 122 patients discontinuing their TKI within the EURO-SKI trial, the one-year relapse-free survival (RFS) was 30.1% (95% CI 15.6-47.9) for patients with >95 CD86+pDC per 105 lymphocytes, but 70.0% (95% CI 59.3-78.3) for patients with <95 CD86+pDC (hazard ratio (HR) 3.4, 95%-CI: 1.9-6.0; P<0.0001). Moreover, only patients with <95 CD86+pDC derived a significant benefit from longer (>8 years) TKI exposure before discontinuation (HR 0.3, 95% CI 0.1-0.8; P=0.0263). High CD86+pDC counts significantly correlated with leukemia-specific CD8+ T-cell exhaustion (Spearman correlation: 0.74, 95%-CI: 0.21-0.92; P=0.0098). Our data demonstrate that CML patients with high CD86+pDC counts have a higher risk of relapse after TKI discontinuation.


Asunto(s)
Antígeno B7-2/metabolismo , Antígeno CTLA-4/metabolismo , Células Dendríticas/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Adulto , Anciano , Antígeno B7-2/genética , Biomarcadores , Recuento de Células , Células Dendríticas/inmunología , Femenino , Expresión Génica , Humanos , Inmunofenotipificación , Estimación de Kaplan-Meier , Leucemia Mielógena Crónica BCR-ABL Positiva/diagnóstico , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/mortalidad , Masculino , Persona de Mediana Edad , Pronóstico , Inhibidores de Proteínas Quinasas/uso terapéutico , Recurrencia , Inducción de Remisión , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Resultado del Tratamiento , Adulto Joven
5.
Z Orthop Unfall ; 154(6): 601-605, 2016 Dec.
Artículo en Alemán | MEDLINE | ID: mdl-27389387

RESUMEN

Background: This study reports one year post-operative monitoring of the efficacy and safety of iFuse Implant System® in patients with sacroiliac joint syndrome. Material and Methods: After 6 months of inadequate conservative treatment, patients with properly proven ISG syndrome were selected for surgery. The iFuse implants had a triangular profile and coating of porous titanium plasma spray and were used in the minimally invasive procedures. The procedure was performed under general anaesthesia and fluoroscopic control. In each case, three implants were placed. Results: 24 patients (22 f; 92 %; 54.9 ± 14 years) participated in the study. The operations were performed in 11 patients (46 %) on the left and in 13 patients (54 %) on the right. The mean operative time was 42.4 minutes (95 % CI: 35.6-49.3). The reduction in pain intensity on the VAS scale was 58 ± 11 mm (68 ± 7 %). The Oswestry score showed a median decrease of 44 percentage points (57 %). After 12 months, 15 patients (63 %) reported that they were taking no more painkillers. Conclusion: The minimally invasive treatment of patients with sacroiliac joint syndrome using the iFuse Implant System leads to significant analgesic effects over the period of one year; it also contributes significantly to improving the functioning of the patient.


Asunto(s)
Artritis/cirugía , Dolor de la Región Lumbar/prevención & control , Prótesis e Implantes , Articulación Sacroiliaca/patología , Articulación Sacroiliaca/cirugía , Fusión Vertebral/instrumentación , Artritis/complicaciones , Artritis/diagnóstico , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Dolor de la Región Lumbar/diagnóstico , Dolor de la Región Lumbar/etiología , Masculino , Persona de Mediana Edad , Implantación de Prótesis/métodos , Articulación Sacroiliaca/diagnóstico por imagen , Fusión Vertebral/métodos , Síndrome , Resultado del Tratamiento
6.
Leukemia ; 29(5): 1123-32, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25676422

RESUMEN

Tyrosine kinase inhibitors (TKI) have changed the natural course of chronic myeloid leukemia (CML). With the advent of second-generation TKI safety and efficacy issues have gained interest. The randomized CML - Study IV was used for a long-term evaluation of imatinib (IM). 1503 patients have received IM, 1379 IM monotherapy. After a median observation of 7.1 years, 965 patients (64%) still received IM. At 10 years, progression-free survival was 82%, overall survival 84%, 59% achieved MR(5), 72% MR(4.5), 81% MR(4), 89% major molecular remission and 92% MR(2) (molecular equivalent to complete cytogenetic remission). All response levels were reached faster with IM800 mg except MR(5). Eight-year probabilities of adverse drug reactions (ADR) were 76%, of grades 3-4 22%, of non-hematologic 73%, and of hematologic 28%. More ADR were observed with IM800 mg and IM400 mg plus interferon α (IFN). Most patients had their first ADR early with decreasing frequency later on. No new late toxicity was observed. ADR to IM are frequent, but mostly mild and manageable, also with IM 800 mg and IM 400 mg+IFN. The deep molecular response rates indicate that most patients are candidates for IM discontinuation. After 10 years, IM continues to be an excellent initial choice for most patients with CML.


Asunto(s)
Antineoplásicos/administración & dosificación , Benzamidas/administración & dosificación , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Piperazinas/administración & dosificación , Pirimidinas/administración & dosificación , Anciano , Antineoplásicos/efectos adversos , Benzamidas/efectos adversos , Progresión de la Enfermedad , Supervivencia sin Enfermedad , Femenino , Estudios de Seguimiento , Proteínas de Fusión bcr-abl/genética , Proteínas de Fusión bcr-abl/metabolismo , Humanos , Mesilato de Imatinib , Interferón-alfa/uso terapéutico , Masculino , Persona de Mediana Edad , Proyectos Piloto , Piperazinas/efectos adversos , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/efectos adversos , Pirimidinas/efectos adversos , Inducción de Remisión , Resultado del Tratamiento
7.
Leukemia ; 28(10): 1988-92, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24798484

RESUMEN

UNLABELLED: Early assessment of response at 3 months of tyrosine kinase inhibitor treatment has become an important tool to predict favorable outcome. We sought to investigate the impact of relative changes of BCR-ABL transcript levels within the initial 3 months of therapy. In order to achieve accurate data for high BCR-ABL levels at diagnosis, beta glucuronidase (GUS) was used as a reference gene. Within the German CML-Study IV, samples of 408 imatinib-treated patients were available in a single laboratory for both times, diagnosis and 3 months on treatment. In total, 301 of these were treatment-naïve at sample collection. RESULTS: (i) with regard to absolute transcript levels at diagnosis, no predictive cutoff could be identified; (ii) at 3 months, an individual reduction of BCR-ABL transcripts to the 0.35-fold of baseline level (0.46-log reduction, that is, roughly half-log) separated best (high risk: 16% of patients, 5-year overall survival (OS) 83% vs 98%, hazard ratio (HR) 6.3, P=0.001); (iii) at 3 months, a 6% BCR-ABL(IS) cutoff derived from BCR-ABL/GUS yielded a good and sensitive discrimination (high risk: 22% of patients, 5-year OS 85% vs 98%, HR 6.1, P=0.002). Patients at risk of disease progression can be identified precisely by the lack of a half-log reduction of BCR-ABL transcripts at 3 months.


Asunto(s)
Antineoplásicos/uso terapéutico , Benzamidas/uso terapéutico , Proteínas de Fusión bcr-abl/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Piperazinas/uso terapéutico , Pirimidinas/uso terapéutico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Supervivencia sin Enfermedad , Femenino , Glucuronidasa/metabolismo , Humanos , Mesilato de Imatinib , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Masculino , Persona de Mediana Edad , Pronóstico , Modelos de Riesgos Proporcionales , Riesgo , Sensibilidad y Especificidad , Resultado del Tratamiento , Adulto Joven
8.
Leukemia ; 27(6): 1254-62, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23212150

RESUMEN

Minimal residual disease (MRD) after allogeneic stem cell transplantation (SCT) for Ph+ acute lymphoblastic leukemia (ALL) is predictive of relapse. Imatinib administration subsequent to SCT may prevent relapse, but the role of scheduling and its impact on outcome are not known. In a prospective, randomized multicenter trial, we compared the tolerability and efficacy of post-transplant imatinib administered either prophylactically (arm A; n=26) or following detection of MRD (arm B; n=29). Prophylactic imatinib significantly reduced the incidence of molecular recurrence after SCT compared with MRD-triggered imatinib (40% vs 69%; P=0.046). Median duration of PCR negativity was 26.5 and 6.8 months, respectively (P=0.065). Five-year survival in both interventional groups was high (80 and 74.5%), despite premature discontinuation of imatinib in the majority of patients because of poor tolerability. Relapse probability was significantly higher in patients who became MRD positive (P=0.017). In conclusion, post-transplant imatinib results in a low relapse rate, durable remissions and excellent long-term outcome in patients with BCR-ABL1-positive ALL irrespective of whether it is given prophylactically or MRD-triggered. Reappearance of BCR-ABL1 transcripts early after SCT or at higher levels identifies a small subset of patients who do not benefit sufficiently from imatinib, and in whom alternative approaches should be explored.


Asunto(s)
Antineoplásicos/uso terapéutico , Benzamidas/uso terapéutico , Neoplasia Residual , Piperazinas/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Pirimidinas/uso terapéutico , Trasplante de Células Madre , Adolescente , Adulto , Antineoplásicos/efectos adversos , Benzamidas/efectos adversos , Terapia Combinada , Femenino , Humanos , Mesilato de Imatinib , Masculino , Persona de Mediana Edad , Cooperación del Paciente , Piperazinas/efectos adversos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Pirimidinas/efectos adversos , Análisis de Supervivencia , Adulto Joven
9.
Leukemia ; 26(9): 2096-102, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22446502

RESUMEN

In the face of competing first-line treatment options for CML, early prediction of prognosis on imatinib is desirable to assure favorable survival or otherwise consider the use of a second-generation tyrosine kinase inhibitor (TKI). A total of 1303 newly diagnosed imatinib-treated patients (pts) were investigated to correlate molecular and cytogenetic response at 3 and 6 months with progression-free and overall survival (PFS, OS). The persistence of BCR-ABL transcript levels >10% according to the international scale (BCR-ABL(IS)) at 3 months separated a high-risk group (28% of pts; 5-year OS: 87%) from a group with >1-10% BCR-ABL(IS) (41% of pts; 5-year OS: 94%; P=0.012) and from a group with ≤1% BCR-ABL(IS) (31% of pts; 5-year OS: 97%; P=0.004). Cytogenetics identified high-risk pts by >35% Philadelphia chromosome-positive metaphases (Ph+, 27% of pts; 5-year OS: 87%) compared with ≤35% Ph+ (73% of pts; 5-year OS: 95%; P=0.036). At 6 months, >1% BCR-ABL(IS) (37% of pts; 5-year OS: 89%) was associated with inferior survival compared with ≤1% (63% of pts; 5-year OS: 97%; P<0.001) and correspondingly >0% Ph+ (34% of pts; 5-year OS: 91%) compared with 0% Ph+ (66% of pts; 5-year OS: 97%; P=0.015). Treatment optimization is recommended for pts missing these landmarks.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/mortalidad , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Benzamidas , Citarabina/administración & dosificación , Análisis Citogenético , Progresión de la Enfermedad , Femenino , Proteínas de Fusión bcr-abl/genética , Humanos , Mesilato de Imatinib , Interferones/administración & dosificación , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Masculino , Persona de Mediana Edad , Piperazinas/administración & dosificación , Pronóstico , Pirimidinas/administración & dosificación , Inducción de Remisión , Tasa de Supervivencia , Adulto Joven
10.
Acta Neurochir Suppl ; 114: 161-4, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22327684

RESUMEN

INTRODUCTION: Continuous bedside brain tissue oxygenation (p(br)O(2)) monitoring using the Licox system is an established method for detecting secondary ischemia in comatose patients with acute brain injury. The purpose of the current study was to compare the newly introduced Raumedic p(br)O(2) probe with the established standard. METHODS: Eighteen patients with acute traumatic brain injury or aneurysmal subarachnoid hemorrhage had p(br)O(2) probes of both types implanted side by side in the same vascular territory at risk of ischemia. Data were analyzed by the Bland-Altman method as well as random effect regression models to correct for multiple measurements per individual. RESULTS: Both types of probes were able to display spontaneous fluctuations of p(br)O(2) as well as reactions to therapy. Mean measurement difference between the Licox and Raumedic probes was -2.3 mmHg, with corresponding 95% limits of agreement of -32.3 to 27.5 mmHg. Regarding an ischemia threshold of 15 mmHg, both probes were in agreement in 78% and showed disparate results in 22%. CONCLUSIONS: Our data suggest that the p(br)O(2) measurements of the two systems cannot be interchanged. Although we were unable to determine which system delivers more valid data, we do think that more rigorous testing is necessary before implementing the new probe in clinical routine.


Asunto(s)
Encéfalo/irrigación sanguínea , Circulación Cerebrovascular/fisiología , Monitoreo Fisiológico/normas , Oxígeno/análisis , Algoritmos , Encéfalo/patología , Lesiones Encefálicas/patología , Humanos , Monitoreo Fisiológico/métodos , Hemorragia Subaracnoidea/patología , Tomografía Computarizada por Rayos X
11.
Acta Neurochir Suppl ; 114: 187-90, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22327690

RESUMEN

INTRODUCTION: Since its introduction into clinical practice, the Bowman Hemedex® regional cerebral blood flow (CBF) monitor has provided a valuable tool for the bedside assessment of CBF in neurointensive care. The purpose of our study was to estimate the accuracy of CBF measurements between automatically performed self-calibration cycles at regular intervals. METHODS: We analyzed data from 75 CBF probes, predominantly implanted into patients after severe subarachnoid hemorrhage. Automatic recalibration of the regional CBF device was performed every 30 min. CBF data were averaged once per minute and the measurement cycles pooled. Statistical analysis was performed with generalized additive modeling and bootstrapping methods. RESULTS: Mean regional CBF was 24 mL/100 g/min after calibration and showed a mean drift of 2.3 mL/100 g/min per measurement cycle (p < 0.001). In every patient, the drift over the measurement cycle followed an exponential trend, with large heterogeneity between patients (-3.67 to 12.0 mL/100 g/min). A highly significant difference in drift was found for the internal software versions of the monitoring devices (p < 0.001). CONCLUSIONS: Data from the Bowman Hemedex® regional CBF monitor shows an upward measurement drift of clinically relevant magnitude. As the drift follows a stable exponential function over time, recalculation of drift-corrected data is possible after termination of the measurement.


Asunto(s)
Corteza Cerebral/irrigación sanguínea , Circulación Cerebrovascular/fisiología , Monitoreo Fisiológico/instrumentación , Monitoreo Fisiológico/métodos , Tiempo de Circulación Sanguínea , Velocidad del Flujo Sanguíneo/fisiología , Temperatura Corporal , Calibración , Humanos , Modelos Estadísticos , Flujo Sanguíneo Regional/fisiología
13.
Neuroimage ; 6(1): 13-25, 1997 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9245652

RESUMEN

An automated registration algorithm was used to elastically match an anatomical magnetic resonance (MR) atlas onto individual brain MR images. Our goal was to evaluate the accuracy of this procedure for measuring the volume of MRI brain structures. We applied two successive algorithms to a series of 28 MR brain images, from 14 schizophrenia patients and 14 normal controls. First, we used an automated segmentation program to differentiate between white matter, cortical and subcortical gray matter, and cerebrospinal fluid. Next, we elastically deformed the atlas segmentation to fit the subject's brain, by matching the white matter and subcortical gray matter surfaces. To assess the accuracy of these measurements, we compared, on all 28 images, 11 brain structures, measured with elastic matching, with the same structures traced manually on MRI scans. The similarity between the measurements (the relative difference between the manual and the automated volume) was 97% for whole white matter, 92% for whole gray matter, and on average 89% for subcortical structures. The relative spatial overlap between the manual and the automated volumes was 97% for whole white matter, 92% for whole gray matter, and on average 75% for subcortical structures. For all pairs of structures rendered with the automated and the manual method, Pearson correlations were between r = 0.78 and r = 0.98 (P < 0.01, N = 28), except for globus pallidus, where r = 0.55 (left) and r = 0. 44 (right) (P < 0.01, N = 28). In the schizophrenia group, compared to the controls, we found a 16.7% increase in MRI volume for the basal ganglia (i.e., caudate nucleus, putamen, and globus pallidus), but no difference in total gray/white matter volume or in thalamic MR volume. This finding reproduces previously reported results, obtained in the same patient population with manually drawn structures, and suggests the utility/efficacy of our automated registration algorithm over more labor-intensive manual tracings.


Asunto(s)
Algoritmos , Encéfalo/anatomía & histología , Imagen por Resonancia Magnética/métodos , Adolescente , Adulto , Sistemas Especialistas , Humanos , Procesamiento de Imagen Asistido por Computador , Persona de Mediana Edad , Sustancia Gris Periacueductal/anatomía & histología , Esquizofrenia/patología
14.
J Image Guid Surg ; 1(6): 326-38, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-9080353

RESUMEN

The segmentation of MRI scans of patients with white matter lesions (WML) is difficult because the MRI characteristics of WML are similar to those of gray matter. Intensity-based statistical classification techniques misclassify some WML as gray matter and some gray matter as WML. We developed a fast elastic matching algorithm that warps a reference data set containing information about the location of the gray matter into the approximate shape of the patient's brain. The region of white matter was segmented after segmenting the cortex and deep gray matter structures. The cortex was identified by using a three-dimensional, region-growing algorithm that was constrained by anatomical, intensity gradient, and tissue class parameters. White matter and WML were then segmented without interference from gray matter by using a two-class minimum-distance classifier. Analysis of double-echo spin-echo MRI scans of 16 patients with clinically determined multiple sclerosis (MS) was carried out. The segmentation of the cortex and deep gray matter structures provided anatomical context. This was found to improve the segmentation of MS lesions by allowing correct classification of the white matter region despite the overlapping tissue class distributions of gray matter and MS lesion.


Asunto(s)
Algoritmos , Encéfalo/patología , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Esclerosis Múltiple/patología , Humanos
15.
IEEE Trans Med Imaging ; 12(4): 634-42, 1993.
Artículo en Inglés | MEDLINE | ID: mdl-18218457

RESUMEN

A systematic method for the detection and segmentation of microcalcifications in mammograms is presented. It is important to preserve size and shape of the individual calcifications as exactly as possible. A reliable diagnosis requires both rates of false positives as well as false negatives to be extremely low. The proposed approach uses a two-stage algorithm for spot detection and shape extraction. The first stage applies a weighted difference of Gaussians filter for the noise-invariant and size-specific detection of spots. A morphological filter reproduces the shape of the spots. The results of both filters are combined with a conditional thickening operation. The topology and the number of the spots are determined with the first filter, and the shape by means of the second. The algorithm is tested with a series of real mammograms, using identical parameter values for all images. The results are compared with the judgement of radiological experts, and they are very encouraging. The described approach opens up the possibility of a reproducible segmentation of microcalcifications, which is a necessary precondition for an efficient screening program.

16.
Gene ; 86(2): 185-92, 1990 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-2182391

RESUMEN

Cell-cycle-phase-specific cDNA libraries were prepared in the lambda gt10 vector and in the in vitro transcription vector, pBluescript. Plaques of the cDNA libraries prepared in the lambda gt10 vector were differentially screened with (a) in vitro transcripts of the cell-cycle-phase-specific cDNAs cloned in the transcription vector and (b) with first-strand cDNA of mRNA from phase-synchronous cells. The results suggest that first-strand cDNA can be replaced, at least in prescreening experiments, by in vitro transcripts of representative cDNA libraries prepared in in vitro transcription vectors. The fractions of differential clones detected with in vitro transcripts (1.2%) and with first-strand cDNA (1%) were in the same order. Individual clones selected by differential hybridization with in vitro transcripts could be verified by differential hybridization with cell-cycle-phase-specific first-strand cDNA. This indicates that the pattern of stage-specific prevalences of cDNA clones is essentially retained during careful amplifications of large cDNA libraries. The application of in vitro transcripts of stage-specific cDNA for differential screening experiments is of interest in cases where the amount of biological material is either limited or difficult to prepare. It also allows standardization of the probes in repeated screening experiments. Three clones reflecting cell-cycle-phase-specific mRNA prevalences were chosen and analyzed on the sequence level. Two sequences with S-phase prevalences were identified. They code for elongation factor EF1 alpha and for glyceraldehyde-3-phosphate dehydrogenase, respectively. The third sequence reflects the first cDNA of a mRNA with significant prevalence in G2-phase cells.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Carcinoma de Ehrlich/genética , ADN de Neoplasias/genética , Transcripción Genética , Secuencia de Aminoácidos , Animales , Carcinoma de Ehrlich/patología , Ciclo Celular , Células Clonales , Escherichia coli/genética , Amplificación de Genes , Biblioteca de Genes , Técnicas Genéticas , Vectores Genéticos , Proteínas de la Membrana/genética , Ratones , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Señales de Clasificación de Proteína/genética , ARN Mensajero/genética , ARN Mensajero/aislamiento & purificación
19.
Rontgenblatter ; 41(4): 147-51, 1988 Apr.
Artículo en Alemán | MEDLINE | ID: mdl-3387862

RESUMEN

The study aimed at evaluating the effect of different methods of digitisation of radiographic films on the digital classification of pulmonary opacities. Test sets from the standard of the International Labour Office (ILO) Classification of Radiographs of Pneumoconiosis were prepared by film digitisation using a scanning microdensitometer or a video digitiser based on a personal computer equipped with a real time digitiser board and a vidicon or a Charge Coupled Device (CCD) camera. Seven different algorithms were used for texture analysis resulting in 16 texture parameters for each region. All methods used for texture analysis were independent of the mean grey value level and the size of the image analysed. Classification was performed by discriminant analysis using the classes from the ILO classification. A hit ratio of at least 85% was achieved for a digitisation by scanner digitisation or the vidicon, while the corresponding results of the CCD camera were significantly less good. Classification by texture analysis of opacities of chest X-rays of pneumoconiosis digitised by a personal computer based video digitiser and a vidicon are of equal quality compared to digitisation by a scanning microdensitometer. Correct classification of 90% was achieved via the discribed statistical approach.


Asunto(s)
Interpretación de Imagen Asistida por Computador , Interpretación de Imagen Radiográfica Asistida por Computador , Silicosis/clasificación , Algoritmos , Humanos , Microcomputadores , Pronóstico , Silicosis/diagnóstico por imagen
20.
Rofo ; 147(6): 636-9, 1987 Dec.
Artículo en Alemán | MEDLINE | ID: mdl-2827257

RESUMEN

Classification of opacities in pneumoconiosis was accomplished by textural analysis in digitised chest x-rays. A good discrimination was achieved by a set of 10 parameters. These texture measures were computed by algorithms for edge detection, local extremes, difference statistics, the co-occurrence matrix and the power spectrum. The classes of the training set were classified correctly at 99%. A test set comprising additional classes that were not contained in the training set, was classified at 82%.


Asunto(s)
Interpretación de Imagen Asistida por Computador , Pulmón/diagnóstico por imagen , Interpretación de Imagen Radiográfica Asistida por Computador , Algoritmos , Humanos , Métodos , Neumoconiosis/clasificación , Neumoconiosis/diagnóstico por imagen
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...