Significant Difference In Mean Levels Research Articles

The Measurement of High Density Lipoprotein Subtractions in Patients with Primary Gout Using a Simple Precipitation Method

We have evaluated a simple dextran sulphate precipitation method for measuring high density lipoprotein cholesterol (HDL) subfractions and have used this method to measure plasma HDL2 and HDL3 in a group of 28 patients with primary gout. These patients were found to have significantly lower levels of plasma HDL and HDL2 than a group of healthy controls, matched for age and sex and of similar body mass index (BMI); no significant difference in mean levels of the HDL3 subfraction was found however. We have confirmed the high prevalence of hypertriglyceridaemia in subjects with gout compared to controls and the mean serum triglyceride levels were significantly higher (P less than 0.01) in the gout group than in controls. We have also shown that subjects with high serum triglyceride levels tend to have low plasma HDL2 concentrations, a finding which is consistent with an inverse relationship between these two parameters. These lipid abnormalities may partly explain the high prevalence of premature atherosclerosis in patients with primary gout.

A comparison of response profiles obtained on the mcgill pain questionnaire and an adjective checklist

The response profiles on the McGill Pain Questionnaire (MPQ) were compared with those obtained from a checklist format, consisting of the 78 MPQ words arranged in random order. Both forms were administered to 3 patient groups: (a) primiparae experiencing post-episiotomy pain (n = 60); (b) outpatients attending a rheumatology clinic wisdom tooth extraction (n = 60); and (c) inpatients having undergone wisdom tooth extraction (n = 60). The order of administration was balanced, so that within each patient group 40 patients received either one of the study forms and 20 both, yielding total sample sizes of 120 and 60 for further statistical analyses. Comparison of numbers of words checked in the two formats showed considerable similarity and so for purposes of further comparison, the MPQ structure was imposed on the checklist. This permitted comparison of summary scores, with no significant differences in mean level, with the sole exception of the evaluative subscale. Comparison of individual subgroup profiles on both forms also showed considerable similarity. A second objective was to compare the format in discriminating between patient groups. It was found that the MPQ offered a higher correct classification rate, although there was little in it, with MPQ subgroup scores rather than subscale scores showing marginally better results.

Prevalence of ischaemic heart disease and associations with serum lipoproteins in subjects aged 45 to 64 years. The Speedwell study.

A longitudinal study has been set up to examine the incidence of ischaemic heart disease and its associations with serum lipoproteins including high density lipoprotein cholesterol and its subfractions, certain haemostatic factors, and other "risk' factors. We report here on our pilot study findings. Cross-sectional data were available on 283 men and 68 women aged 45 to 64 representing 85% of the available population randomly selected from the lists of 16 general practitioners. Reproducibility of the measurements of total serum cholesterol, triglyceride, and low density lipoprotein cholesterol was acceptable. The reproducibility of some of the other serum lipid fractions, for example high density lipoprotein cholesterol, was less good, in part because of the small range of the values found for these components. Univariate associations of physical and behavioural characteristics and serum lipoproteins of men and women, with and without ischaemic heart disease, disclosed small and statistically nonsignificant differences except for levels of blood pressure. In particular, there was no significant difference in mean levels of serum high density lipoprotein cholesterol between men with ischaemic heart disease (0.91 mmol/l) and men without it (0.94 mmol/l). In examining our data for the determinants of serum high density lipoprotein cholesterol using a linear multiple regression model, sex, serum high density lipoprotein cholesterol, and very low density lipoprotein triglyceride were the major factors, each individually explaining about 7% of the variance of serum high density lipoprotein cholesterol levels. In addition, alcohol intake and obesity each explained a further 2% of the variance. The experience of the pilot study has led to modifications in the collection of blood samples and the subsequent estimation of lipid fractions.

Pubertal gynecomastia: Evidence for a possible role of the adrenal gland

As part of a longitudinal study of normal puberty, 14 boys who developed gynecomastia and 6 normal boys were followed at 6 month intervals from age 11 to 17 years. Serum levels of E1, E2, Δ4, T, DHEA, DHEA-S and PRL were measured at each interval. Mean age at onset of gynecomastia was 14.0±0.28 years, mean bone age 13.0±0.26 years and mean pubertal stage 2.9±0.13. Over the course of puberty there were no significant differences in mean levels of these hormones. However, ratios of E1/Δ4, E1/DHEA and E1/DHEA-S were consistently higher in the gynecomastia group between ages 12½ and 15 years. The same tendency was noted for these ratios for bone age years 12½ to 15 and pubertal stages 2 through 4. Conversely the ratio of E2/T remained essentially the same between the two groups. These results suggest that either adrenal secretions or increased peripheral conversion of Δ4 to E1 may play a role in the appearance of pubertal gynecomastia in normal boys.

Volume Reverberation as a Function of Single Frequency Pulse Lengths and FM Sweep Rates

Volume-reverberation tests were conducted with a vertically directional transducer at a frequency of 15.4 kHz. For each of two source levels, the system was capable of transmitting single frequency (SF) pulses of 10-, 50-, 100-, 300-, and 1000-msec duration and 1000-msec frequency-modulated (FM) pulses swept 100, 200, and 400 cycles. The relationship between volume reverberation level and pulse length is investigated. The data show a less than linear dependence of volume reverberation on pulse length and a linear dependence on source level. Reverberation levels for FM and SF pulses of 1000-msec duration are discussed. Although the amplitudes of the deviations from the mean reverberation are lower in the FM mode than the SF mode, no significant difference in mean levels is observed.