A population-based analysis of pediatric breast cancer

Purpose

The purpose of this study was to evaluate trends in demographics and outcomes of pediatric breast cancer in a United States population-based cohort.

A preliminary statistical model for identifying repeaters of parasuicide

This paper presents a statistical model constructed using logisticregression to identify those at high-risk of repeating parasuicide. Thesubjects in the study are Cork city residents who exhibited parasuicidalbehaviour between 1 January and 30 June 1995. Repetition of the behaviourwithin six months of the index episode distinguishes repeaters fromnon-repeaters. The model was designed so that it could be used bynon-clinicians and hence does not require information relating topsychiatric diagnosis or use of psychiatric services. The proportion ofsubjects correctly classified remained stable across a range of cut-pointprobabilities (mean = 86%, range: 83.9–87.5%). Using acut-point of 0.2, 96% of repeaters and 81% of non-repeaters were correctly classified. Using 0.45 led to the correct identification of81% of repeaters and 90% of non-repeaters. If these highlevels of sensitivity and specificity are maintained in validation tests onfuture cohorts in Cork city then the model could form the basis of anintervention programme designed to prevent the repetition of parasuicide.     

Smoking and raven IQ

Nicotine has recently been shown to enhance measures of information processing speed including the decision time (DT) component of simple and choice reaction time and the string length measure of evoked potential waveform complexity. Both (DT and string length) have been previously demonstrated to correlate with performance on standard intelligence tests (IQ). We therefore hypothesised that nicotine is acting to improve intellectual performance on the elementary information processing correlates of IQ. In the current experiment we tested this hypothesis using the Raven Advanced Progressive Matrices (APM) test. APM scores were significantly higher in the smoking session compared to the non-smoking session, suggesting that nicotine acts to enhance physiological processes underlying performance on intellectual tasks.     

Interactions of retinoic acid and androgens in human prostatic tissue.

The effect of retinoic acid (RA) on testosterone metabolic pathway was investigated in hyperplastic and neoplastic human prostatic tissues, and also the effects of steroids on RA binding to its receptor. Steroids only had a minimal effect on the binding of RA by its receptor. The conversion of testosterone to DHT by 5 alpha-reductase was reduced in the presence of retinoic acid. The inhibition was probably due to competition with NADPH for enzyme binding sites. The degree of inhibition found with retinoic acid at a concentration of 10(-4)M was greater for hyperplastic (41%) than that for neoplastic tissue (24%). The inhibition of 5 alpha-reductase by retinoic acid was dose-dependent. The activity of 5 alpha-reductase is significantly less in neoplastic compared with hyperplastic tissue.     

A model of waveform reliability in facial nerve electroneurography

This study identifies four factors that should be considered when evaluating the reliability of new testing methods in facial nerve electroneurography (ENOG): (1) waveform peak-to-peak amplitude; (2) response variability; (3) statistical significance of day-to-day test/retest differences; and (4) waveform morphology. These factors were applied to data gathered on seven normal subjects who had three trials of facial-nerve ENOG on three separate test days in order to determine an optimal recording electrode montage. Both bipolar and monopolar recording-electrode montages were used on the nasal alae and on the nasolabial crease. Resultant peak-to-peak amplitudes of combined motor action potentials were recorded and measured using a clinical evoked-potential instrument. A biphasic waveform shape with optimal peak-to-peak point rather than the nasolabial crease. The contribution to the assessment of response reliability of each of the four factors is discussed.     

Viral dynamics and their relations to baseline factors and longer term virologic responses in treatment-naive HIV-1-infected patients receiving abacavir in combination with HIV-1 protease inhibitors

From a study of 71 HIV-1-infected patients receiving abacavir in combination with 1 of 5 different HIV-1 protease inhibitors (indinavir, ritonavir, saquinavir, nelfinavir, or amprenavir), we found that the baseline HIV-1 RNA levels were highly predictive of the viral decay rates. The baseline HIV-1 RNA levels were negatively correlated with the first phase viral decay rates (r = -0.77, P < 0.001) and positively correlated with the second phase viral decay rates (r = 0.68, P < 0.001). In addition, the first phase viral decay rate was positively correlated with CD4+ cell increases. No significant correlation was found between viral decay rates and longer term (24 weeks) virologic responses, and no difference in viral decay rates was found among the 5 study regimens. These data suggest that the potency of the 5 treatment regimens was similar and was not predictive of long-term virologic failure.