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Biomedical subjects

S G Ratcliffe

Publications and source records attributed to S G Ratcliffe.

33 records · Page 2Linked to original sources
PubMed1982

Klinefelter's syndrome in adolescence.

Twelve boys with Klinefelter's syndrome (47,XXY) identified by sex chromatin screening at birth were examined at between ages 16 and 18 years, together with 12 controls matched for social class and birth order from the same newborn population. Physical examination, psychometric assessment, personality, and degree of psychosexual development were assessed without knowledge of the karyotype. Anthropometry showed increased leg length and decreased head circumference in the XXY boys. Gynaecomastia was present in 4 boys, and testicular volume was reduced in the majority but one boy had normal sized testes. On the Wechsler intelligence scale there was a significant reduction in verbal score but not in either performance or full-scale score compared with the controls. Although appreciable differences were found in growth, personality, intelligence test scores, and psychosexual development, these were of small degree.

Adolescent↗
PubMed1981

Inheritance of a ring 14 chromosome.

A family is described in which the mother, her two live offspring, and a therapeutically aborted fetus each had a ring 14 chromosomes. The two children were mentally retarded and the mother's intelligence was at the lower end of the normal range. In addition, the mother had two spontaneous abortions, one of which was shown to be chromosomally normal.

Adult↗
PubMedDate not supplied

Assessing non-linear estimation procedures for human growth models.

BACKGROUND: In the last 20 years several non-linear models with a relatively small number of parameters have provided useful descriptions of the complete human growth curve. However, some aspects of the estimation procedures used have not been properly studied, e.g. estimation of biases, measures of non-linearity, and the possibility of autocorrelated errors and heteroscedasticity. OBJECTIVES: To present a detailed analysis of these aspects for five well-known non-linear models (Preece-Baines, Shohoji-Sasaki and three models proposed by Jolicoeur et al.) and a large data set (the MRC Edinburgh Longitudinal Study). SUBJECTS: A cohort of 74 females and 103 males collected for the Edinburgh Longitudinal Study for the MRC Human Genetics Unit, Edinburgh, UK, comprising approximately quarterly height measurements for small ages and semestral height measurements for the remaining ages up to the early twenties. RESULTS: We found little evidence of extreme curvature and relatively small, cyclical patterns in the residuals. The estimates obtained with ordinary non-linear least squares were very close to those obtained with more complicated estimation procedures. CONCLUSIONS: The five models studied are reasonably robust against most of the problems encountered when fitting non-linear models to human growth data; this confirms some conjectures which have been taken for granted by a large number of authors. The presence of cyclical patterns is a consequence of the global description of growth attempted by these five models.

Female↗
PubMedDate not supplied

The cyclical nature of prepubertal growth.

We have examined the complete longitudinal height velocity (HV) data of 135 (80 male and 55 female) chromosomally normal children from the Edinburgh Longitudinal Growth Study who were measured six-monthly between age 3 years and the onset of the adolescent growth spurt. Individual HV curves appeared to consist of a regular series of accelerations and decelerations in a cyclical fashion. After excluding variations due to measurement error, and basing the analysis on the pattern of acceleration, we were able to identify a number of spurts of regular occurrence. The mid-childhood spurt was clearly identified at ages 7.0 in boys and 6.7 years in girls, and could be identified in all children except one girl. Other spurts were also apparent; a pre-school spurt at ages 4.8 and 4.6, a late-childhood spurt at ages 9.2 and 8.6, and in children with an average-to-late onset of puberty, a prepubertal spurt at ages 10.8 and 10.0 years in boys and girls respectively. Synchronization at peak HV was performed for each spurt as described by Shuttleworth (1937) for the adolescent growth spurt. The overall pattern of growth appeared to be cyclical with a mean peak interval of 2.2 years in boys and 2.1 years in girls, the cycles appearing to continue until interrupted by the onset of the adolescent growth spurt. Sitting height velocity (SHV) and leg length velocity (LLV) curves also showed a cyclical pattern, but each varied independently. The magnitude of the HV spurts in an individual was dependent on the synchrony between the phases of SHV and LLV spurts. The cyclical pattern of prepubertal growth with its rapid changes in HV should be taken into account when assessing the growth of any child and in the response to any treatment offered.

Adolescent↗
PubMedDate not supplied

A new method of deriving velocity and acceleration curves for height from the kernel estimation of distance.

Further development of the optimal kernel (OK) method of growth curve analysis of Gasser et al. (1984b) is presented with the aim of eliminating the necessity of repeated changes in bandwidth to suit different characteristics of the velocity and acceleration curves at varying ages. After using the OK method to obtain a distance curve for height, we introduce a new method (VADK) to derive velocity and acceleration curves from the fitted distance curve. The results from growth data on 16 boys and 15 girls from the Edinburgh Longitudinal Study are presented in a preliminary test of this method in comparison with the OK estimation.

Age Factors↗
PubMedDate not supplied

Growth during puberty in the XYY boy.

The availability of a cohort of eight unselected XYY boys identified by newborn cytogenetic screening has enabled their growth to be studied longitudinally in comparison with controls from the same population. While no difference had been found in dimensions at birth, increased height velocity in childhood resulted in the XYY boys being 7.6 cm taller at the onset of their pubertal growth spurt. Increased intensity of growth at puberty with a peak height velocity of 10.6 cm/year contributed to their adult height of 188.1 cm. XYY boys showed twice the male-female difference in height implying that genes on the Y chromosome exert a quantitative effect on the sexual dimorphism of growth.

Body Height↗
PubMedDate not supplied

The growth of XXX females: population-based studies.

Longitudinal measurements of height, sitting height and leg length are compared between 11 XXX girls identified by cytogenetic screening, and 16 chromosomally normal controls from the same population using a nonparametric method. While height velocity did not differ between the two groups either during the pubertal or the mid-childhood spurts, leg length velocity was significantly increased during the mid-childhood spurt, between 4 and 9 years of age. A further contribution to the increased leg length came from the slower decline in leg length velocity at the end of the pubertal spurt. The possible mechanisms involved in these changes are discussed.

Adolescent↗