Biomedical subjects
Publications and source records attributed to P Bolton.
We report a male individual with partial tetrasomy 15 and severe mental retardation, who met ICD-10 criteria for autism. The relevance of this to the etiology of autism is discussed.
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Two previous epidemiological studies of autistic twins suggested that autism was predominantly genetically determined, although the findings with regard to a broader phenotype of cognitive, and possibly social, abnormalities were contradictory. Obstetric and perinatal hazards were also invoked as environmentally determined aetiological factors. The first British twin sample has been re-examined and a second total population sample of autistic twins recruited. In the combined sample 60% of monozygotic (MZ) pairs were concordant for autism versus no dizygotic (DZ) pairs; 92% of MZ pairs were concordant for a broader spectrum of related cognitive or social abnormalities versus 10% of DZ pairs. The findings indicate that autism is under a high degree of genetic control and suggest the involvement of multiple genetic loci. Obstetric hazards usually appear to be consequences of genetically influenced abnormal development, rather than independent aetiological factors. Few new cases had possible medical aetiologies, refuting claims that recognized disorders are common aetiological influences.
A young adult female with multiple exostoses, short stature, autism, mental retardation and 46,X,t(X;8)(p22.13;q22.1) is described. Although the clinical features and translocation breakpoints raise the possibility of a number of specific conditions, the constellation of problems is not consistent with any previously reported genetic syndrome. It is argued that her clinical disorder is likely due to the chromosomal abnormality and that further detailed molecular genetic investigation may shed light on the genetic basis to various components of her phenotype including the autism.
The use of the family history method to examine the pattern of recurrence risks for complex disorders such as autism is not straightforward. Problems such as uncertain phenotypic definition, unreliable measurement with increased error rates for more distant relatives, and selection due to reduced fertility all complicate the estimation of risk ratios. Using data from a recent family history study of autism, and a similar study of twins, this paper shows how a latent-class approach can be used to tackle these problems. New findings are presented supporting a multiple-locus model of inheritance, with three loci giving the best fit.
The introduction of computers to Australian general practice will require changes beyond those of simply changing from pen to keyboard. The form in which information is stored has a major impact on how it can be used. General practitioners should be informed about this potential and take part in decision making about the use of computers.
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Family history data on 99 autistic and 36 Down's syndrome probands are reported. They confirmed a raised familial loading for both autism and more broadly defined pervasive developmental disorders in siblings (2.9% and 2.9%, respectively, vs 0% in the Down's group) and also evidence for the familial aggregation of a lesser variant of autism, comprising more subtle communication/social impairments or stereotypic behaviours, but not mental retardation alone. Between 12.4 and 20.4% of the autism siblings and 1.6% and 3.2% of the Down's siblings exhibited this lesser variant, depending on the stringency of its definition. Amongst autistic probands with speech, various features of their disorder (increased number of autistic symptoms; reduced verbal and performance ability) as well as a history of obstetric complications, indexed an elevation in familial loading. No such association was seen in the probands without speech, even though familial loading for the lesser variant in this subgroup, was significantly higher than in the Down's controls. The findings suggest that the autism phenotype extends beyond autism as traditionally diagnosed; that aetiology involves several genes; that autism is genetically heterogeneous; and that obstetric abnormalities in autistic subjects may derive from abnormality in the foetus.
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Rates of birth in the general population show seasonal fluctuations for reasons that are ill understood. Variations from these general population patterns have been reported for several psychiatric conditions and used as the basis for aetiological hypotheses. In this paper, the evidence for alterations in the expected seasonal fluctuation in birth dates of autistic people is evaluated. A national sample of 1435 autistic individuals and a clinic sample of 196 subjects are compared to general population figures and to 121 sibling controls. Compared with the general population, the national sample showed significant deviations from the expected rate of birth by month. In the clinic sample, differences from the anticipated monthly pattern were only evident when this sample was compared to the sibling controls. A variety of models for seasonal trends, including year quarters, temperature and sine wave forms, were fitted to these variations but no consistent picture emerged.
A questionnaire study was conducted in the Mushandike small scale irrigation schemes in Zimbabwe to investigate the following: 1) to establish whether field latrines are used or not; 2) to find out why people visit natural water bodies for bathing and laundry instead of using water from boreholes for these purposes; 3) to assess people's knowledge on the transmission and control of schistosomiasis. Results of the study indicated that the field latrines are utilised and that the borehole water is not preferred for bathing and laundry because of its hardness and oily nature. The results further indicated that the community was aware of schistosomiasis but their knowledge on transmission and control of the disease was limited. Possible reasons for the observations made are discussed in the paper and recommendations emanating from the study are stated.
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Macrophages are a source of many important mediators of wound repair. It was the purpose of this study to see if light could stimulate the release of these mediators. In this study an established macrophage-like cell line (U-937) was used. The cells were exposed in culture to the following wavelengths of light: 660 nm, 820 nm, 870 nm, and 880 nm. The 820-nm source was coherent and polarised, and the others were non-coherent. Twelve hours after exposure the macrophage supernatant was removed and placed on 3T3 fibroblast cultures. Fibroblast proliferation was assessed over a 5-day period. The results showed that 660-nm, 820-nm, and 870-nm wavelengths encouraged the macrophages to release factors that stimulated fibroblast proliferation above the control levels, whereas the 880-nm wavelength either inhibited the release of these factors or encouraged the release of some inhibitory factors of fibroblast proliferation. These results suggest that light at certain wavelengths may be a useful therapeutic agent by providing a means of either stimulating or inhibiting fibroblast proliferation where necessary. At certain wavelengths coherence is not essential.
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The potential contribution by engineers to the control of schistosomiasis in irrigation schemes is examined with reference to work in Zimbabwe. In larger schemes, snail control using molluscicides has proved effective. In smaller schemes, where this is impracticable, careful design and operation may reduce transmission. Appropriate measures are currently being assessed in a pilot project.