RESUMEN
42 dyslexic and 42 ordinary readers were given a rapid sequential short-term memory task using materials adapted from the Illinois Test of Psycholinguistic Abilities Visual Sequential Memory subset. Dyslexic readers performed at a similar level to ordinary readers. In Study 2, the same readers were given a 10-piece form board to complete as quickly as possible. Dyslexic readers were significantly slower on this task. Since short-term memory was not a feature of the second task, it was reasoned that short-term memory problems were unlikely to be a feature of dyslexic's performances on rapid sequential processing tasks.
Asunto(s)
Atención , Dislexia/psicología , Tiempo de Reacción , Aprendizaje Seriado , Adolescente , Niño , Dislexia/diagnóstico , Femenino , Humanos , Masculino , Recuerdo Mental , Reconocimiento Visual de ModelosRESUMEN
Six laboratories participated in the Fifth International Workshop on Lymphocyte Alloantigens of the Horse, testing 132 alloantisera against lymphocytes of 880 horses chosen to represent different families and breeds. Most of the alloantisera were produced by lymphocyte immunization between horses matched at the ELA-A locus. All horses were also tested with antisera contributed to the workshop by participating laboratories which identified ELA specificities A1-A10 and W12-W21. Previously identified workshop specificities ELA-W14, W15 and W19 were accepted as products of the ELA-A locus based on family and population studies by the workshop. Their designations were changed to ELA-A14, ELA-A15 and ELA-A19, respectively. Two new specificities were identified, namely ELA-W22 (W22) and ELA-W23 (W23). Population and family studies indicated that W22 and W23 as well as W13 are products of an ELA locus other than ELA-A. The presence of these specificities was correlated with the presence of certain ELA-A locus specificities, e.g. W13 with A3, W22 with A2 and W23 with A5. However, the association was not complete and W13, W22 and W23 also segregated with other ELA-A specificities in some families. Evidence for recombination was found between the ELA-A locus and the locus or loci encoding these specificities resulting in seven recombinant haplotypes found among the data presented in this workshop. Further studies are required for definitive assignment of the specificities to a class I or class II locus.
Asunto(s)
Caballos/inmunología , Isoantígenos/análisis , Linfocitos/inmunología , Animales , Tipificación y Pruebas Cruzadas Sanguíneas/veterinaria , Epítopos/genética , Epítopos/inmunología , Frecuencia de los Genes , Antígenos de Histocompatibilidad/análisis , Antígenos de Histocompatibilidad/genética , Antígenos de Histocompatibilidad/inmunología , Antígenos de Histocompatibilidad Clase II/análisis , Antígenos de Histocompatibilidad Clase II/genética , Antígenos de Histocompatibilidad Clase II/inmunología , Caballos/genética , Isoantígenos/genética , Isoantígenos/inmunología , Complejo Mayor de HistocompatibilidadRESUMEN
The effects of the existing filtration system upon a narrow, parallel beam of X rays were considered. The profile of a Cu filter to be placed on the tube-side A1 wedge was calculated on the basis that the total energy incident on the detector box would remain unchanged when the other A1 wedge was removed. A Cu wedge was machined according to this profile. The effects of this modification on surface radiation dose delivered to a 25 cm EMI water phantom were both predicted and measured for horizontal traverses, and were in broad agreement. The reduction in integral radiation dose to the 25 cm water phantom was predicted as 39%. Dose reductions measured at several points on the surface and within an Alderson Rando anthropomorphic phantom head averaged 53% and 20% respectively. The modified system was evaluated in terms of imaging ability, and although some degradation was seen, images of the EMI composite phantom remained "diagnostic" in quality, despite non-ideal responses of some photomultiplier tubes at intermediate and extreme positions of the traverse periphery.
Asunto(s)
Tomografía Computarizada por Rayos X/instrumentación , Cobre , Filtración/instrumentación , Modelos Estructurales , Dosis de RadiaciónRESUMEN
The count rate responses of a gamma camera and data analysis system have been shown to behave as two separate components. Five systems made up of combinations of two static gamma cameras, two data analysis systems, and a mobile gamma camera system were investigated. Camera and data analysis system dead times are quoted and percentage corrections are plotted against radioactivity of 99 Tcm in a patient phantom within the field of view. It is recommended that such a detailed study should be performed for any gamma camera system as part of a quality assurance programme.
Asunto(s)
Conteo por Cintilación , Rayos gamma , Conteo por Cintilación/instrumentaciónRESUMEN
Axillary lymphoscintigraphy using 99Tcm antimony sulphide colloid has been carried out in 29 patients with suspected breast cancer and was correlated with histology. Of the 23 with proved tumour, axillary node metastases were found in 19 and, although 10 did have diminished uptake on the side of the lesion, 5 had an equal uptake in both sides and 4 had an increased uptake on the side of the lesion. Further, some of the nodes in which the high uptake had occurred were those heavily infiltrated by tumour. It is concluded that: a, lymphoscintigraphy with antimony sulphide colloid is not a reliable technique for the detection of metastatic disease in the regional nodes; b, any lymphoscintigraphy with this or any other agent requires more meticulous histological correlation than hitherto before it can be assumed to have any proved clinical value.
Asunto(s)
Antimonio/metabolismo , Neoplasias de la Mama/diagnóstico por imagen , Coloides , Ganglios Linfáticos/metabolismo , Metástasis Linfática/diagnóstico por imagen , Compuestos de Tecnecio , Tecnecio/metabolismo , Axila , Humanos , Metástasis Linfática/metabolismo , Metástasis Linfática/patología , CintigrafíaRESUMEN
In quantitative analyses of dynamic radionuclide studies, using large activities of 99mTc flowing through organs it is necessary to determine accurately count-rate losses and to provide appropriate corrections. A method is described for estimating deadtimes and applying corrections to the observed counting rates using a two component model where the gamma camera is considered to have a purely paralyzable deadtime and the data analysis system a purely non-paralyzable deadtime.
Asunto(s)
Cintigrafía/instrumentación , Tecnecio , Tecnología RadiológicaAsunto(s)
Radioisótopos de Yodo/metabolismo , Protección Radiológica/normas , Glándula Tiroides/efectos de la radiación , Contaminación Radiactiva del Aire/análisis , Carga Corporal (Radioterapia) , Ingestión de Líquidos , Humanos , Radioisótopos de Yodo/análisis , Matemática , Concentración Máxima Admisible , Dosis de Radiación , Respiración , Glándula Tiroides/metabolismo , Factores de Tiempo , Contaminación Radiactiva del Agua/análisisRESUMEN
During the course of a kinetic enzyme study of bisphosphoglyceromutase (EC 2.7.5.4.) a chemiluminescent effect was encountered in the liquid scintillation counting of the beta-emission from 32Pi. A method is described for overcoming the effect, thereby permitting the accurate determination of the radioactive compounds. It is important to check for chemiluminescent effects early in the development of new procedures that involve liquid scintillation counting.
Asunto(s)
Mediciones Luminiscentes , Radioisótopos de Fósforo , Conteo por Cintilación , Concentración de Iones de Hidrógeno , Cinética , Fosfoglicerato Mutasa , Factores de TiempoRESUMEN
Responses from one manual and four automatic gamma counters for assaying (125)I were compared. The resolution times quoted by manufacturers when applied in a standardized correction formula to obtain true counts from observed counting rates above 10(4) counts per second appeared to be inadequate. The need to investigate the errors associated with high counting rates for all instruments and electronic settings employed to determine (125)I in radioimmunoassays is emphasized.
Asunto(s)
Radioisótopos de Yodo/análisis , Radioinmunoensayo/métodos , Semivida , Matemática , Radiometría , Conteo por Cintilación , SolucionesAsunto(s)
Enfermedades de la Tiroides/sangre , Tiroxina/sangre , Absorción , Adolescente , Adulto , Proteínas Sanguíneas , Femenino , Humanos , Hipertiroidismo/sangre , Hipertiroidismo/diagnóstico , Hipotiroidismo/sangre , Hipotiroidismo/diagnóstico , Métodos , Persona de Mediana Edad , Embarazo , Unión Proteica , Pruebas de Función de la Tiroides , Triyodotironina/metabolismoRESUMEN
Evidence from both animal and human studies had been presented by various authors to suggest that reduction of pancreatic function increased iron absorption. The present experimental studies in rats showed that there was increased radioiron ((59)Fe) absorption after pancreatectomy, but this appeared to be due to the operative procedure as there was a similar increased absorption in animals who had sham operations performed. There was no certain evidence that pancreatic enzymes or extract had a specific inhibitory effect on the absorption of iron. But with increased doses of pancreatic extract, above the normal doses, the amount of radioiron absorption was greatly enhanced.A significant increase in hepatic storage iron was found in the groups of rats who had been fed a diet supplemented with dl-ethionine. All these animals showed extensive damage and atrophy of the pancreas, with degeneration and considerable regenerative activity in the liver. The absolute increased hepatic storage iron was not due to the liberation and laying down of haemosiderin from the damaged cells or to decreased liver mass. Rats who had carbon tetrachloride-induced liver cirrhosis without pancreatic damage showed no increased hepatic storage iron. It was observed that in liver damage with considerable cellular proliferation there was increased liver iron content. As this was found only when there was associated pancreatic injury, it is suggested that decreased pancreatic function in the presence of liver cell injury with cellular proliferation leads to increased iron absorption and storage. The relationship of liver injury with cellular proliferation and pancreatic damage to increased hepatic storage iron merits further study.