Language and social behaviour in severely educationally subnormal children

There is a strong positive relationship between age and the number of social interactions a child is likely to initiate during a typical classroom free-play period. The type of interaction which shows the largest increase is verbally initiated child-child interactions. Verbally initiated child-teacher interactions also increase with age, though not so markedly as child-child interactions. There appears to be no significant change in non-verbal initiations of interactions with age, either to the teacher or to peers. These results give support to the use of observational techniques for language assessment in that they give further information about the growth of productive language skills as reported in a population survey of language abilities in mentally handicapped school children.     

Figure copying in Williams syndrome and normal subjects

We evaluated the copying abilities of ten subjects with Williams syndrome (WS; age 6–14 years) and ten normally developing children (age 3–6 years) matched for mental age using the matrices component of the Kaufman Brief Intelligence Test (mKBIT). Each subject copied six figures, including line drawings of closed and open geometrical shapes (alone and in combination), crossed lines, and geometrical shapes made of distinct small, filled circles. Qualitatively, subjects of both groups made comparable copies, although several subjects with WS drew a continuous line when copying figures composed of distinct circles. Quantitatively, the goodness of the copies was assessed by three human observers who rated on an analog scale the similarity of each copy to its visual template. Ratings were converted to a scale from zero (completely different) to 100 (the same) for statistical analyses. We found the following. First, the overall goodness of copies of the templates was very similar between the WS and control groups (WS: mean=46.7, range=0.89–95.4; control: mean=54.5, range=0.89–98.2). Second, there were systematic differences in the goodness of copies between the two groups, depending on the features of the figures. Specifically, the goodness of copies of control subjects was almost the same as that of WS subjects for simple line figures, but was consistently better for composite line figures, and even better for figures in which the shape was made of small, filled circles. Third, there was a significant relation between the goodness of copies (dependent variable) and mental age (mKBIT, independent variable) in both groups, although it was stronger and more highly statistically significant in the control than the WS group. These findings indicate that the principles guiding copying are similar in the two groups and suggest that WS is a case of developmental rather than deviance disorder.An erratum to this article can be found at     

Age-related increase of mitomycin C-induced micronuclei in lymphocytes from Down's syndrome subjects

Peripheral blood lymphocytes from 7 patients with Down's syndrome (DS; trisomy 21) and 14 healthy age-matched controls were studied for the induction of micronuclei (MN) by the cytokinesis-block method. The spontaneous incidence of MN in lymphocytes from DS subjects was lower than that of control cultures. When lymphocytes were treated with mitomycin C (MMC) at the beginning of the culture period, an increase in MN formation was found in cells from both DS and control subjects. In DS subjects this increase was much more marked than in control donors. This effect had to be ascribed to cells from older DS subjects (37–55 years old), which showed an MMC-induced MN formation that was markedly and significantly higher than that observed in cells from younger (9–16 years old) DS subjects.These data indicate that age has to be considered a major variable when studies on the genetic instability of DS subjects are performed.     

Distribution of anti-keratins and anti-thymostimulin antibodies in normal and in Down's syndrome human thymuses.

The localization of three monoclonal (A,B,C) anti-cytokeratin antibodies and of an anti-thymostimulin antibody were studied in normal children's thymuses, aged from 2 months to 10 1/2 years and in Down's children thymuses, aged from 5 months to 6 1/2 years. Two anti-cytokeratins were positive in the thymus: the anti-B was found in the epithelial cells of all thymic zones, the anti-C only in the external cells of Hassall's corpuscles. The distribution and the intensity of immuno-reactions were the same in normal and in Down's thymuses. The distribution of anti-thymostimulin was superimposed to the distribution of anti-cytokeratin B and was similar in normal and in the youngest Down's thymuses, whereas in the 6 1/2 years-old Down's thymuses there was a loss of anti-TS reaction in the subcapsular zone. A relationship between the reduction of anti-thymostimulin immuno-reaction and the beginning of an eventual loss of T-lymphocyte differentiation was supposed.     

A study of digestive absorption in four cases of Down's syndrome. Down's syndrome, malnutrition, malabsorption, and Alzheimer's disease

Many data suggest that patients with Down's syndrome (DS) suffer from digestive malabsorption. A fecal test of absorption (search for undigested meat fibers following the ingestion of a measured diet) was conducted in 4 patients with DS. The results point to malabsorption in these patients and support the hypothesis of malabsorption in DS. The etiology of probable malabsorption in DS is discussed. Data are presented suggesting that chronic malnutrition caused by malabsorption could be the cause of the neuropathologic signs of Alzheimer's disease occurring at or slightly before the fourth decade in all patients with DS.     

Developmental pattern of muscarinic receptors in normal and Down's syndrome fetal brain--an autoradiographic study.

The ontogeny of muscarinic cholinergic receptors in developing human brain was analyzed by in vitro receptor autoradiography with [3H]Quinuclidinyl Benzilate. It was found that muscarinic receptors develop relatively early; the levels at 24 weeks of gestation were comparable or even higher then the values in the adult brain, and that the levels of both M1 and M2 receptors increase with age. M1 receptors were concentrated mainly in forebrain regions while M2 receptors dominated in the thalamus. Scatchard analysis revealed Kd and Bmax values which are comparable to the adult values. Three brains of aborted Down's syndrome fetuses were examined in parallel and exhibited comparable levels and similar distribution to normal non-Down fetuses except for a modest increase of receptor levels which was observed in the striatum.     

Kell types in Down's syndrome

To test for linkage of the Kells locus to the chromosome trisomic in Down's syndrome, 585 mongoloid and 585 non-mongoloid retardates matched for county of residence were tested. No significant difference in the frequencies of Kell types was detected. The frequency of Kell positives among mongoloids was almost identical to that observed in an independent sample of blood donors drawn from one community in North Carolina. Efforts to detect doasage effects using twofold dilutions of anit-K and anti-k were unsuccessful. Though no evidence for linkage was detected, it is recognized that the possibility of linkage has not been absolutely excluded bt only made less probable.     

Pulmonary hypoplasia in Down's syndrome

We studied the lungs of seven patients of various ages who had Down's syndrome, to determine whether they had abnormalities in pulmonary development. Six of the seven had hypoplastic lungs. Five had congenital heart disease, but pulmonary hypoplasia was of equal severity, irrespective of the presence or absence or the type of congenital heart disease. Three other patients with congenital heart disease but without Down's syndrome had lungs that were equally diminished in volume. However, these lungs lacked the structural abnormalities seen in Down's syndrome, which consisted of a diminished number of alveoli in relation to acini and enlarged alveoli and alveolar ducts. The patients with Down's syndrome also had a smaller total number of alveoli and a smaller alveolar surface area. We speculate that the smaller alveolar surface area is accompanied by loss of capillary surface area, which is responsible for the aggravation of pulmonary hypertension in Down's syndrome.     

Alzheimer's disease and Down's syndrome

The neuropathology of Down's syndrome at middle age is compared with that of Alzheimer's disease at that age, through a review of the published literature and from the author's personal observations. The pathological changes of Down's syndrome at middle age, i.e. the form and distribution of senile plaques and neurofibrillary tangles, and the pattern of involvement (atrophy) of neuronal systems are qualitatively the same as those of Alzheimer's disease at that age. Quantitative differences do occur and these may relate to biological or sociological variations inherent to the two parent populations. It is concluded that, in pathological terms, patients with Down's syndrome at middle age do indeed have Alzheimer's disease. Some ways in which a study of patients with Down's syndrome can give insight into the nature and development of the pathological changes of Alzheimer's disease are put forward and discussed.     

Erythrocyte anomalies in Down's syndrome

It is suggested that anomalies in Down's syndrome /DS/ erythrocyte /E/ features are due to accelerated E aging. This, in turn, can be conditioned by augmented free-radical exposure. Accelerated cell aging in DS may be the reason for immune system derangement.     

Platelet abnormalities in Down's syndrome

Nine individuals with Down's syndrome and 12 normal children were studied. Platelets from Down's syndrome (DS) were smaller than normal and had reduced numbers and volumes of electron dense bodies. Whole cell and dense body calcium levels were lower than normal, while platelet surface net negative charge and anionic sites were found to be elevated in DS platelets. The findings suggest a calcium-related membrane abnormality as one of the defects in DS platelets.