2,252 research outputs found

    Ca 125 in the physiology and pathology of the female reproductive tract: With particular reference to the diagnosis of ovarian cancer

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    This thesis addresses the hypothesis that "the CA 125 tumour associated antigen is of value in the diagnosis of ovarian cancer". The literature concerning CA 125 and diagnostic aspects of ovarian cancer are reviewed in chapter 1 and the research methodology and the characteristics of CA 125 assay systems are described in chapters 2 and 3. Chapters 4-6 describe studies of the compartmental distribution of CA 125 in the female reproductive tract in physiological and pathological states. The results suggest that CA 12 5 is a product of normal endometrium, pregnancy endometrium and benign ovarian tumours as well as malignant ovarian tumours, and that there is a physiological rise in serum CA 125 levels during menstruation and early pregnancy. It is concluded that the main factor influencing serum levels of CA 12 5 is the integrity of the blood: tissue barrier. Chapter 7 describes a prospective study to evaluate serum CA 125 measurement in the preoperative diagnosis of ovarian cancer. The results indicate that the accuracy of CA 125 measurement is superior to clinical criteria and similar to ultrasound. The highest diagnostic accuracy was achieved by combining CA 125, ultrasound and menopausal status in a risk of malignancy index. Chapter 8 describes phase 1 of a prospective study of screening for ovarian cancer amongst postmenopausal women. The results indicate that to achieve satisfactory specificity will require a multimodal approach combining CA 125 measurement with either pelvic examination or ultrasonography. Chapter 9 is a report of a phase 2 study of screening for ovarian cancer using the sequential combination of CA 125 and ultrasound. The preliminary results in 20,000 postmenopausal volunteers suggest that the lead time achieved over clinical presentation using this screening protocol is greater than 1 year. It is concluded that despite limitations of specificity and sensitivity, CA 125 is of value in the preoperative diagnosis of ovarian cancer and may have a role in a multimodal screening protocol for early stage disease

    Properties Of Simultaneous Discrete Occasion Setters

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    This series of experiments used 80 to 120 day old water-deprived rats (Rattus norvegicus) to investigate whether simultaneously presented discrete occasion setters shared two properties of serially presented discrete occasion setters. Results of Experiment 1 revealed that all groups showed a strong reinstatement effect. In the second experiment a target stimulus was first trained as a predictor of shock and then paired with a simultaneously presented occasion setter to inhibit responding to the target stimulus. The occasion setter was then paired with a shock. Due to a limitation of the procedures, results from Experiment 2 were inconclusive. The third experiment tested whether simultaneously presented occasion setters would only transfer to other targets that underwent occasion setting training. Results from Experiment 3 revealed strong contextual control over behavior that overshadowed the ability of the features to modulate responding to the targets. A fourth experiment addressed limitations from Experiment 3. Results from Experiment 4 revealed that simultaneous discrete occasion setters were unable to transfer to another target stimulus. Overall results from this experiment indicate that simultaneously presented cues do not act as occasion setters

    An investigation of best practices in youth development programmes at selected football academies in the Western Cape.

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    Magister Artium (Sport, Recreation and Exercise Science) - MA(SRES)Football around the globe has been used as a vehicle for youth development initiatives. Youth development programmes foster social change in communities and provide an ideal development context that often results in active sport participation. In South Africa, there are a number of youth development programmes that not only use football, but also other sporting codes to implement and create sustainable youth development programmes. Therefore, the aim of this study was to explore best practices in youth development programmes of selected football academies in the Western Cap

    HIV-1 TAT1-86 INDUCED EFFECTS ON EXTINCTION AND RELAPSE IN FEAR CONDITIONING LEARNING

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    HIV-1 Associated Neurocognitive Disorder (HAND) is a neurodegenerative condition affecting roughly 30-50% of HIV-1 infected individuals. Symptoms include a wide range of cognitive impairments, but this series of experiments focuses on deficits in learning and memory. Specifically, these experiments investigate behavioral deficits in associative learning using fear conditioning methodology. The transactivator of transcription (Tat), In humans, the severity of symptoms is most strongly correlated with the severity of synaptic disruption and dendritic injury. Of the HIV-1 viral proteins, Tat plays a key role in facilitating structural and functional dendritic defects in neurons. Within the brain, Tat has several direct and indirect effects that result in structural and functional changes to regions of the brain crucial for associative learning. Fear conditioning using a Tat transgenic mouse model of HAND allows for the study of these affected regions while minimizing the influence of motivational systems. In fear conditioning, subjects are presented with a conditioned stimulus (CS) followed by unconditioned stimulus (US). The subject learns an association between the two, and performs a conditioned response (CR), indicative of learning, in preparation for the US. The acquisition of this response can then undergo extinction in which the US is presented multiple times without the US, thus reducing the conditioned response. Finally, relapse in conditioned responding can be observed due to changes in context, and reminders of the US. There are regionspecific contributions to each of these learning processes, allowing for the connection between specific deficits and associated brain regions. The current series of experiments investigated acquisition, extinction, and relapse of conditioned responding.Results from these experiments reveal transient deficits in acquisition for male and female Tat(+) subjects and a transient deficit in extinction learning seen only in male Tat(+) subjects. These findings indicate disruption to amygdala and prefrontal cortex circuitry. Renewal, a contextual form of relapse, was not observed while reinstatement, a US reminder form of relapse, was. These results indicate that the failure to observe renewal were not due to failure to recall acquisition memories. Overall, these experiments establish clear methodology for investigating associative learning deficits in the Tat transgenic mouse model of HAND and demonstrate transient deficits related to acquisition and extinction.Doctor of Philosoph

    Systematic review of predictive performance of injury severity scoring tools

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    Many injury severity scoring tools have been developed over the past few decades. These tools include the Injury Severity Score (ISS), New ISS (NISS), Trauma and Injury Severity Score (TRISS) and International Classification of Diseases (ICD)-based Injury Severity Score (ICISS). Although many studies have endeavored to determine the ability of these tools to predict the mortality of injured patients, their results have been inconsistent. We conducted a systematic review to summarize the predictive performances of these tools and explore the heterogeneity among studies. We defined a relevant article as any research article that reported the area under the Receiver Operating Characteristic curve as a measure of predictive performance. We conducted an online search using MEDLINE and Embase. We evaluated the quality of each relevant article using a quality assessment questionnaire consisting of 10 questions. The total number of positive answers was reported as the quality score of the study. Meta-analysis was not performed due to the heterogeneity among studies. We identified 64 relevant articles with 157 AUROCs of the tools. The median number of positive answers to the questionnaire was 5, ranging from 2 to 8. Less than half of the relevant studies reported the version of the Abbreviated Injury Scale (AIS) and/or ICD (37.5%). The heterogeneity among the studies could be observed in a broad distribution of crude mortality rates of study data, ranging from 1% to 38%. The NISS was mostly reported to perform better than the ISS when predicting the mortality of blunt trauma patients. The relative performance of the ICSS against the AIS-based tools was inconclusive because of the scarcity of studies. The performance of the ICISS appeared to be unstable because the performance could be altered by the type of formula and survival risk ratios used. In conclusion, high-quality studies were limited. The NISS might perform better in the mortality prediction of blunt injuries than the ISS. Additional studies are required to standardize the derivation of the ICISS and determine the relative performance of the ICISS against the AIS-based tools
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