Early influences on the secular change in adult height between the parents and children of the 1958 birth cohort

The present account is of data available from the 1958 British national birth cohort and its follow-up to the age of 23 years. It shows an increase in adult height between the cohort members and their parents, amounting to an average 1.2 +/- 0.11 (SEM) cm between the daughters and their mothers and 3.0 +/- 0.12 cm between the sons and their fathers. Factors in early life which contributed jointly to a significant increase in adult height included, as well as sex and parental height, birthweight and maternal pre-pregnant weight, while increasing gestational age had a negative effect. Overall these factors accounted for 71% of the variance of the cohort members' height. Measuring the intergenerational difference between individual pairs of sons and father and daughters and mothers allows to some extent for social and genetic influences. This showed that the size of the difference was increased by increasing intrauterine growth rate, and falling paternal social class. These findings demonstrate again the lifelong influence on offspring of circumstances pertaining at their birth and explain why it may take more than one generation to overcome the effects of childhood disadvantage.

Mercury in the stomach contents of dab (Limanda limanda) from the North East Irish Sea and Mersey Estuary

A study of mercury concentrations in the stomach contents of fish from the north-east Irish Sea and Mersey Estuary has been shown to provide a means for surveillance of geographical and time-based changes in environmental exposure of fish biota to mercury in marine and estuarine ecosystems. This paper describes data for the flatfish dab (Limanda limanda), caught during the period 1986-1988. The low degree of variability in the data enables confirmation of clear trends in mercury concentration in stomach contents over time. As the inputs of mercury to the sewage sludge dumping ground in Liverpool Bay have decreased, there has been a corresponding decrease in mercury in fish food items. The mean mercury value in stomach contents around the dump site has declined to 100 microg kg(-1) (wet weight) which now predominates over the whole of Liverpool Bay. In 1986, mercury concentrations in stomach contents of fish ranged to over 750 microg kg(-1) although the majority of values were below 200 microg kg(-1). Most of the sites within the Mersey Estuary produced mean concentrations which were similar to those in the open sea, except for Garston which is the site closest to an inland, and principal alternative, source of mercury.

An inverse relationship between serum zinc and C-reactive protein levels in acutely ill elderly hospital patients

Serum zinc and C-reactive protein (CRP) levels were measured in two groups of acutely ill geriatric hospital in-patients. Serum CRP levels were greater than 10 mg/l in 62% of the first group and 47% of the second. There was a significant negative correlation between zinc and CRP in both groups (r = -0.33, P less than 0.001, n = 103) and (r = -0.29, P less than 0.001, n = 135 respectively). The serum CRP was raised in 30% of long stay patients (n = 50) and 23% of a control group of elderly hospital patients with a normal serum albumin (n = 71), but there was no correlation between zinc and CRP in these patient groups. The results indicate that an acute phase response influences serum zinc levels in acutely ill geriatric patients. There is reason to believe that a distinction should be made between true zinc deficiency and a low serum zinc secondary to acute zinc redistribution during an inflammatory response. Measurement of CRP may help to distinguish between these two situations. We advise that if the serum zinc is low and CRP is significantly raised, zinc supplements should be avoided and a source of infection should be sought. Following recovery from severe infection low serum zinc levels return to normal while elevated CRP levels fall.

Cerebral palsy: why we must plan for survival

The survival of children in the South East Thames region, born between 1970 and 1979 and diagnosed as having some form of cerebral palsy was investigated. Of the 732 children studied, 651 (90%) are still alive, and hence cerebral palsy must be regarded as a condition with which people live rather than a condition of which they die. Survival varies considerably among the different diagnostic groups: those suffering from spasic quadriplegia, dyskinetic and 'mixed' cerebral palsy are most severely affected. Our evidence suggests that, though immobility and severe mental subnormality are the strongest predictors of mortality in children with cerebral palsy, the majority of even the most severely affected patients survive to adulthood. It is therefore appropriate to plan for their survival by funding and evaluating programmes to maximise health, independence, and quality of life.

Statistics for medical students in the 1990's: how should we approach the future?

Medical statistics teaching in the U.K. has moved over the past twenty years from needing justification to acceptability. In the future teachers need to involve statistical and medical colleagues to improve the content and presentation of their material. While some techniques must continue to be taught, the conceptual aspects of scientific evaluation and assessment will need to increase.

Sperm morphological analysis: comparison of two methods in human semen

Sperm morphological analysis was performed by 2 methods: light microscopy on Papanicolaou stained material and scanning electron microscopy. Both methods were found to have acceptably low levels of observer error and a positive correlation existed between them. Sperm morphology was analysed by both methods in 2 groups: (1) 104 proven "fertile" men, husbands of women who had just given birth and whose paternity had been proven by HLA studies with greater than 95.5% certainty; (2) 53 infertile men from primary infertile marriages in whom no female cause could be found and excluding those with azoospermia. There was no statistically significant difference in medians between the 2 groups when sperm morphology was analysed by light microscopy, but analysis by scanning electron microscopy did show a significant difference.

A study of serum zinc, albumin, alpha-2-macroglobulin and transferrin levels in acute and long stay elderly hospital patients

Serum zinc levels measured by atomic absorption spectrophotometry were found to be low (less than 10.5 mumols/l) in 38% of acute geriatric admissions, 69% of long stay geriatric patients and 19% of a control group of elderly hospital patients with a normal serum albumin. There was a significant positive correlation between serum zinc and serum albumin in all groups. In acutely ill geriatric patients only, there was a weak but statistically significant positive correlation between serum zinc and alpha-2-macroglobulin (A2M) (r = 0.20), P less than 0.05). Serum transferrin was low in 46% of acute geriatric patients and 22% of long stay geriatric patients but there was no correlation between serum zinc and serum transferrin levels in any patient group. There were significant differences in serum zinc, A2M and transferrin levels between the acute and long stay geriatric patients. The differences in serum zinc levels between these patients groups could not be explained by changes in serum A2M, transferrin or albumin. Changes mediated by an acute phase response may have influenced results in the acute geriatric group of patients.

Sperm motility, velocity and migration

Four different methods for evaluating sperm motility were analysed for experimental error: subjective assessment of a wet film preparation, sperm velocity measured by time-lapse photography, sperm velocity measured by computer analysis and sperm migration across a nucleopore membrane. Subjective assessment of motility was found to be inaccurate, within single observer and between 2 observers. Both methods of measuring mean sperm velocity were accurate, particularly that using the computer analysis system; a high technical failure rate was found using time-lapse photography. Sperm migration across a nucleopore membrane was found to be highly inaccurate. Two groups were then analysed for the predictive value of these tests (excluding sperm migration): 104 proven fertile men and 53 infertile men. Although subjective motility was able to predict from which group the sample came at optimum cut-off with 78% accuracy, computer analysed sperm velocity could predict with overall 91% accuracy at optimum cut-off. Computer analysis of sperm velocity offers a rapid, objective and predictive assessment of sperm function.

Sperm density measurement: should this be abandoned?

Sperm density measurement by means of the Makler chamber was performed on a single semen specimen from 2 groups: 104 proven fertile men and 53 infertile men; 11.5% of the fertile population had a sperm density less than 20 million/ml (median 84, mean 91.3, SD 60.5) and 33% of the infertile population had a sperm density greater than 20 million/ml (median 10, mean 26.9, SD 34.8). There was a statistically significant difference in median between the 2 groups, but when a discriminant analysis was applied, sperm density could predict fertile status with only 68% accuracy at optimum cut-off. Sperm density is valueless in distinguishing fertile from infertile men and is neither useful in diagnosis nor in monitoring the progress of treatment for male infertility. It should be abandoned as a quotable measurement of male fertility.

The measurement of migration of the acetabular component of hip prostheses

Individual components of a total hip replacement are difficult to evaluate and quantify. We have studied the assessment of the acetabular component, and conclude that the measurement of migration allows the comparison of implants, although there is no established link between migration and significant loosening. A method of measurement based on clinical radiographs has been developed, and its limitations estimated. The accuracy of the technique was calculated to be +/- 3 mm.

Automatic speech recognition--can it improve the man-machine interface in medical expert systems?

Computer-aided medical diagnosis has existed for two decades, but has not yet attained widespread acceptance among physicians. It is proposed that automatic speech recognition may be a significant factor in the eventual acceptance of the technology by the medical profession. The current state-of-the-art of automatic speech recognition is briefly surveyed, and problems with the technology are discussed. A potential natural language interface with DIAG, an expert system for aiding in dermatologic diagnosis, is described. A system that has been developed for accepting input of body parts in freestyle format is presented as a prototype for a natural language interface with an automatic speech recognition device.

Lymphoproliferative cancer and other malignancy in patients with rheumatoid arthritis treated with azathioprine: a 20 year follow up study

Two hundred and two patients with rheumatoid arthritis (RA) starting treatment with large doses of azathioprine (median 300 mg/day) between 1964 and 1974 were followed up until March 1984. All but one patient (99.5%) were traced from either hospital or general practice records; and death certificates, where relevant, were obtained. A comparison group of 202 patients with RA not treated with azathioprine was selected from the diagnostic index of another rheumatology unit and followed up in 1985 to assess their status retrospectively at March 1984. Each patient treated with azathioprine was matched for year of birth, year of diagnosis, sex, and serostatus with a control patient from the latter group. Four lymphoproliferative cancers occurred in the azathioprine treated group compared with two in the control group. Further analysis of these findings suggested an increased risk of lymphoma of one case per 1000 patient years of azathioprine treatment. The lymphoma rates were then compared with those expected based on the incidence in the general population. This comparison suggested a fivefold increase in the RA control group and a 10-fold increase in the azathioprine treated group. There was also an excess of patients with non-lymphoproliferative cancers, including one with myeloma in the azathioprine group (29 v 19), the excess being greater in the group with the longest duration of treatment. This significantly increased risk did not, however, persist on matched analysis, was not related to maximum daily dose, and was not site specific. These results from a possibly unique series of patients treated with high dose azathioprine give some reassurance about the magnitude of the previously postulated carcinogenic risk of such treatment in RA.

Relative power of clinical, exercise test, and angiographic variables in predicting clinical outcome after myocardial infarction: the Newham and Tower Hamlets study

The interrelations of clinical, exercise test, and angiographic variables and their relative values in predicting specific clinical outcomes after myocardial infarction have not been fully established. Of 302 consecutive stable survivors of infarction, 262 performed a predischarge submaximal exercise test. In the first year after infarction patients with a "positive" exercise test were 13 times more likely to die, 2.8 times more likely to have an ischaemic event, and 2.3 times more likely to develop left ventricular failure than patients with negative tests. Patients with positive exercise tests underwent cardiac catheterization. Features of the history, 12 lead electrocardiogram, in-hospital clinical course, exercise test, and left ventricular and coronary angiograms that predicted these clinical end points were identified by univariate analysis. Then multivariable analysis was used to assess the relative powers of all variables in predicting end points. Certain features of the exercise test remained independent predictors of future ischaemic events and the development of overt left ventricular failure, but clinical and angiographic variables were more powerful predictors of mortality. Because the exercise test is also used to select patients for angiography, however, the results of this study strongly support the use of early submaximal exercise testing after infarction.

How can we design trials to detect clinically important changes in disease severity?

1. Forty-eight British rheumatologists judged the change in disease activity in 50 sets of patient data drawn from life and presented as 'paper patients'. Each set comprised two values, recorded a year apart, for 10 commonly measured clinical variables. Doctors recorded the size of improvement or deterioration on a visual analogue scale (VAS) and whether the change was clinically important or not. 2. Clinical judgement policies were modelled using linear regression of the clinical variables on the VAS score. 3. Doctors showed little agreement over which patients had improved and which had not. Possible reasons could be discovered by inspecting their judgement policies. 4. The weights attributed to the clinical variables differed considerably between doctors. Furthermore weights the doctors believed they attached to the variables frequently differed from the weights in the regression models. 5. These models could be used to calculate the smallest change required in any clinical variable before it would be considered clinically important. However, the size of such changes was often outside the observed clinical range suggesting that the use of single outcome variables is unrealistic. 6. The modelling procedure described can be applied during the planning stage of the trial to participating physicians, patients, health economists or any other group having an interest in the results. The models themselves can then be used to reach a consensus policy for judging what is a successful outcome. This may be expressed as a linear combination of specific outcome measures. Its use may improve the power of clinical trials and the relevance of their results.

Small bowel disease in children: diagnosis with CT

The computed tomographic (CT) scans of 22 children with small bowel disease and those of 110 children with no small bowel disease were analyzed by two observers who were blinded with respect to clinical history and final diagnoses in order to determine which CT findings reliably indicated neoplastic, inflammatory, or noninflammatory processes. Bowel-wall thickening was the most reliable sign of disease. Five of six patients (83%) with bowel-wall thickness greater than 1 cm had neoplastic disease. Nine of ten patients (90%) with bowel-wall thickness between 3 mm and 1 cm had inflammatory disease, while four of six patients (66%) with wall thickness less than 1 cm and increased attenuation of mesenteric fat or an increase in the number of mesenteric vessels had noninflammatory edema. The presence of mesenteric masses was not a helpful sign for differentiating various disease processes. The results of this retrospective study suggest that the identification and classification of small bowel disease in children is possible from the objective analysis of CT findings.

A comparison of excitatory amino acid antagonists acting at primary afferent C fibres and motoneurones of the isolated spinal cord of the rat

The potency of 7 excitatory amino acid antagonists had been measured at kainate receptors on primary afferent C fibres using isolated dorsal roots from immature rats. Two of the compounds were tested as antagonists of excitant amino acids at motoneurones using isolated hemisected spinal cord preparations. Mean dose-ratios for antagonism of kainate at C fibres, produced by 1 mM antagonist in at least four preparations, ranged from 2.1 +/- 0.5 (mean +/- s.e.mean) with 2-amino-5-phosphonopentanoate (AP5) to 17.6 +/- 2.4 with 1-(p-bromobenzoyl)-piperazine-2, 3-dicarboxylate (BBpzD). The rank order of potency of antagonists at C fibres was similar to that obtained previously for antagonism of kainate at motoneurones. The potency of kynurenate as an antagonist of kainate at C fibres (apparent Kd 70 +/- 4.3 microM (mean +/- s.e.mean), n = 12) was significantly different (P less than 0.005, Wilcoxon rank sum) from its potency at motoneurones (apparent Kd 164 +/- 14 microM, n = 13). Kynurenate also was significantly (P less than 0.025 Wilcoxon rank sum) more potent at antagonizing kainate- than quisqualate (apparent Kd 258 +/- 28 microM, n = 12)-induced depolarization of motoneurones. Kynurenate and BBpzD (0.25, 1.0 and 4.0 mM) were compared as antagonists of N-methyl-D-aspartate (NMDA) at motoneurones and the slope of the Gaddum-Schild plot for kynurenate was markedly greater than 1 (2.01 +/- 0.22, 95% confidence limits). A greater than additive antagonism of NMDA-induced depolarizations was produced by combinations of kynurenate with, either AP5, or magnesium ions. 5. The results suggest that the kainate receptor on C fibres may be different from the kainate receptor on motoneurones and that antagonism of NMDA-induced depolarization by kynurenate may not be entirely competitive.

Blood pressure and migration: a study of Bengali immigrants in East London

The role of blood pressure in explaining the increased risk of ischaemic heart disease (IHD) in Bengali immigrants living in the East End of London was studied in a comparative population study. In addition the effect on blood pressure of age, body mass, and duration of stay in the UK was evaluated. The Bengalis had significantly lower mean systolic and diastolic blood pressures though these differences disappeared after adjustment for age and body mass. Both groups, however, showed similar rises of blood pressure with increasing age and body mass. The effect on blood pressure of duration of time spent in the UK by the Bengalis could not be separated from that due to age, given the association between them. It seems unlikely that increasing duration of stay in inner London per se has a hypertensive effect on Bengali immigrants coming from a rural community. Further, the increased IHD risk in this group is not explained, even in part, by an increase in blood pressure.