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Biomedical subjects

K Godfrey

Publications and source records attributed to K Godfrey.

13 recordsLinked to original sources
PubMed1990

Linear IgA disease of adults: association with lymphoproliferative malignancy and possible role of other triggering factors.

Seventy patients with linear IgA disease of adults were followed up for a mean of 8.5 years and all malignant diseases in this group were ascertained. There were three cases of lymphoproliferative malignancy, which constituted a significant excess over the 0.2 cases that would be expected by comparison with an age- and sex-matched population using National Cancer Registry statistics. In contrast, the non-lymphoid malignancy rate of 13% is almost identical to the expected 14%. A subgroup of 35 of the adult linear IgA disease patients were assessed with respect to the possible precipitating illnesses or drugs, as well as co-existing medical conditions. Almost one-third of patients described an event that was felt could possibly have triggered the linear IgA disease, the most frequent being non-steroidal anti-inflammatory or antibiotic drug therapy, trauma/burns and upper respiratory tract infections. However, it is difficult to determine how often the preceding event is coincidental, and how often, if at all, it is causal.

Adolescent↗
PubMed1990

Assessment and predictability of ANB angle.

This cephalometric study consisting of thirty three orthodontic patients in the age group of 13 to 15 years was carried out to: 1. Evaluate the relationship between angle ANB and horizontal distance between jaws at the level of point A (r = 0.99); 2. Evaluate the relationship between angle ANB and Wits appraisal (r = 0.95 when mandibular plane angle is within normal limits of 32 +/- 5); 3. Predict angle ANB from Wits appraisal and vice versa (which was 90 percent correct in mesofacial type and obtained by the regression equation: angle ANB = 2.31 + 1.00 x Wits value; and 4. Evaluate the validity of angle ANB compared to other methods (angle ANB 78.5 percent in agreement with the standard followed by Wits 64.28 percent).

Adolescent↗
PubMed1990

The reproducibility of Johnston's cephalometric superimposition method.

A method of cephalometric superimposition, described by Johnston (1986), was evaluated to determine its reliability. Fifteen pairs of before- and after-treatment cephalograms, were measured five times, and an analysis of variance (ANOVA) was carried out on the measurements to check for any significant differences between the repeated measures. The results of the analysis found Johnston's method of cephalometric superimposition to be reliable and consistent, with lower standard deviations in the measurements found, compared to other commonly used methods.

Analysis of Variance↗
PubMed1985

Simple linear regression in medical research.

This article discusses the method of fitting a straight line to data by linear regression and focuses on examples from 36 Original Articles published in the Journal in 1978 and 1979. Medical authors generally use linear regression to summarize the data (as in 12 of 36 articles in my survey) or to calculate the correlation between two variables (21 of 36 articles). Investigators need to become better acquainted with residual plots, which give insight into how well the fitted line models the data, and with confidence bounds for regression lines. Statistical computing packages enable investigators to use these techniques easily.

Humans↗
PubMed1985

Statistics in practice. Comparing the means of several groups.

This article discusses statistical methods for comparing the means of several groups and focuses on examples from 50 Original Articles published in the Journal in 1978 and 1979. Although medical authors often present comparisons of the means of several groups, the most common method of analysis, multiple t-tests, is usually a poor choice. Which method of analysis is appropriate depends on what questions the investigators wish to ask. If the investigators want to identify which of the groups under study are different from the rest, they will need a different method from the one required if they wish simply to decide whether or not the groups share a common mean. More complicated questions about the group means call for more sophisticated techniques. Of the 50 Journal articles examined, 27 (54 per cent) used inappropriate statistical methods to analyze the differences between group means. Investigators need to become better acquainted with statistical techniques for making multiple comparisons between group means.

Analysis of Variance↗