神经肽DGAVP和Org2766对神经细胞内游离Ca2+的影响

运用Ca²⁺指示剂Fura-2作为细胞内钙离子的荧光探针,利用AR—CM—MIC阳离子测定系统,检测了分离的神经细胞内游离钙及其变化,并观测了DGAVP和Org2766对蛋白质合成抑制剂茴香霉素(ANI)引起细胞内钙离子浓度([Ca²⁺]_i)变化的影响。结果表明茴香霉素可使[Ca²⁺]_i显著升高,且有量效关系;DGAVP本身并不引起[Ca²⁺]_i发生显著变化,但适当剂量的DGAVP可显著对抗一定剂量范围内ANI升高[Ca²⁺]_i的作用,提示DGAVP对抗ANI的蛋白质合成抑制效应可能是通过拮抗ANI升高[Ca²⁺]_i这一途径实现的,另一神经肽Org2766则可能不是通过这一机制发生作用。从细胞内Ca²⁺的角度看,这两种肽的作用机理显然是不同的。     

Repetitive and ritualistic behaviour in children with Prader–Willi syndrome and children with autism

Background Recent research has shown that the range of repetitive behaviour seen in individuals with Prader–Willi syndrome (PWS) extends beyond food‐related behaviour. Methods The presence and intensity of repetitive, rigid and routinized behaviour in children with PWS was compared with that seen in children with another neurodevelopmental condition in which repetitive behaviour is common: children with autism. Parents completed the Childhood Routines Inventory (CRI). Results Contrary to our predictions, controlling for developmental level, children with PWS and children with autism showed similar levels of repetitive and ritualistic behaviour overall and on the two CRI factors measuring ‘just right’ and ‘repetitive’ behaviour. Indeed, the majority of the sample of parents of children with PWS endorsed most items on the CRI. However there was some specificity at the level of individual items with parents of children with PWS more frequently endorsing an item on ‘collecting and storing objects’ and parents of children with autism more frequently endorsing ‘lining up objects’, ‘has a strong preference for certain foods’ and ‘seems aware of detail at home’. Conclusions These findings confirm the range of repetitive behaviours that form part of the behavioural phenotype of PWS, including insistence on sameness and ‘just right’ behaviours, and uncover a surprising overlap with those seen in children with autism. Clinical management for children with PWS should include advice and education regarding management of repetitive and rigid behaviour. Future research should investigate whether the repetitive behaviours that form part of the behavioural phenotype of both PWS and autism are associated with a common neuropsychological, neurotransmitter or genetic origin.     

Book review

Books reviewed in this article:
Problems in Optometry Series Volume 4 No: Ocular Vertical and Vertical and Cyclovertical Deviations Edited by Richard London.     

Auditory discrimination and auditory sensory behaviours in autism spectrum disorders

It has been hypothesised that auditory processing may be enhanced in autism spectrum disorders (ASD). We tested auditory discrimination ability in 72 adolescents with ASD (39 childhood autism; 33 other ASD) and 57 IQ and age-matched controls, assessing their capacity for successful discrimination of the frequency, intensity and duration differences in pairs of sounds. At the group level, auditory discrimination ability did not differ between the adolescents with and without ASD. However, we found a subgroup of 20% of individuals in the ASD group who showed ‘exceptional’ frequency discrimination skills (defined as 1.65 SDs above the control mean) and who were characterised by average intellectual ability and delayed language onset. Auditory sensory behaviours (i.e. behaviours in response to auditory sensory input) are common in ASD and we hypothesised that these would relate to auditory discrimination ability. For the ASD group, poor performers on the intensity discrimination task reported more auditory sensory behaviours associated with coping with loudness levels. Conversely, those who performed well on the duration discrimination task reported more auditory sensory behaviours across the full range measured. Frequency discrimination ability did not associate with auditory sensory behaviours. We therefore conclude that (i) enhanced frequency discrimination is present in around 1 in 5 individuals with ASD and may represent a specific phenotype; and (ii) individual differences in auditory discrimination ability in ASD may influence the expression of auditory sensory behaviours by modulating the degree to which sounds are detected or missed in the environment.     

Guilt in obsessive-compulsive disorder

Despite the phenomenological and theoretical importance of guilt in obsessive-compulsive disorder, research in this area has been conducted primarily on normal populations and has produced contradictory results. This study had two aims. First, to compare the guilt of subjects with obsessive-compulsive disorder (n = 30) to the guilt of normal controls (n = 30); second, to examine the relationships among guilt, anxiety, depression, and obsessions in an obsessional and normal population. Obsessional subjects reported significantly more trait guilt, state guilt, and higher moral standards than normal controls. In both populations, trait guilt significantly predicted obsessional compulsive complaints, independent of anxiety and depression. The results are considered in relation to the literature on inflated perceived responsibility for threat; the specific nature of obsessional guilt is discussed.     

MEASUREMENT OF THE AXIAL WAVEFRONT ABERRATION OF THE HUMAN EYE

An objective variation of Howland and Howland's subjective crossed-cylinder aberroscope method of estimating ocular aberration is described. An ophthalmoscopic arrangement allows the distorted retinal image of the aberroscope grid to be directly photographed for later analysis. Results for 10 subjects show that the ocular wavefront aberration near the visual axis is rarely symmetrical about the pupil centre and that, as a result, the phase transfer function is generally non-zero. Calculated modulation transfer functions at various pupil diameters broadly agree with those of earlier authors but suggest that marked differences occur between individual eyes when the pupil diameter exceeds about 3 mm.     

Accommodation and convergence: effects of lenses and prisms in ''closed-loop'' conditions

Experiments are described in which the steady-state accommodation response to binocularly viewed targets at various distances in the range 0.2-5 m was measured by laser optometry in normal, near-emmetropic subjects. Responses were determined with naked-eye viewing and when equal pairs of either spherical lenses or base-in or base-out prisms were placed before the eyes. Snellen acuity was also measured under the same range of conditions. The results show that, although the most accurate accommodation responses were found under natural viewing, the response accuracy was remarkably robust against both lenses and prisms. There was, however, always some change in response level to any increment in lens or prism power. The results are discussed in terms of earlier theories and data on the general relationship between accommodation and convergence.