Infectious exposure in the first year of life and risk of central nervous system tumors in children: analysis of day care, social contact, and overcrowding.

Little is known regarding the aetiology of central nervous system tumors in children. Recent studies have speculated on a potential infectious aetiology, but no clear associations have been found. This article uses parent reported questionnaire data from the UK Childhood Cancer Study (UKCCS), a population-based case-control study, to examine the relationship between the infectious exposure in the first year of life and the likelihood of developing a CNS tumor. The variables representing infectious exposure were social contact (including social contact with other infants and attendance at informal and formal day care), sharing a bedroom with another child, birth order, and exposure to a school-age child within the home. Children reported to have had no social contact with other infants in the first year of life displayed an increased risk of developing a CNS tumor when compared to those who had (OR 1.37, 95% CI 1.08-1.75). This effect was most prominent in the primitive neuroectodermal tumor/medulloblastoma subgroup (OR 1.78, 95% CI 1.12-2.83). Those who had attended informal (OR 0.86, 95% CI 0.68-1.09) or formal day care (OR 0.93, 95% CI 0.68-1.26) showed slightly non-statistically significant reduced risks when compared to those reporting social contact only. No association with any of the other variables was observed. Overall, the inconsistent findings by variable and tumor subtype suggest that an early exposure to infections is not strongly implicated in the aetiology of CNS tumors. However, the effect for social contact outside the home, particularly for PNET/medulloblastomas warrants further investigation.

Atopic dysfunction and risk of central nervous system tumours in children.

Risk factors for central nervous system (CNS) tumours in children remain largely unknown. Evidence of an inverse relationship between atopy and tumour development exists in adults but little is known about childhood tumours. This study aims to examine the risk of childhood CNS tumours given a history of eczema and asthma. Cases of children diagnosed with CNS tumours (n=575) and controls (n=6292) from the UK Childhood Cancer Study (UKCCS) were analysed using conditional logistic regression comparing reported histories of allergic disease. Asthma was statistically significantly and negatively associated with all CNS tumours (odds ratios, OR 0.75, confidence of interval, CI(95%): 0.58-0.97), though this was not observed for eczema (OR 0.94, CI(95%): 0.74-1.18). Individuals who had suffered both asthma and eczema showed the most significant reduction in risk (OR 0.48, CI(95%): 0.28-0.81). Analysis by tumour subtype showed the strongest effect for the medulloblastoma/PNET group. These results may have a biological explanation with raised immunosurveillance in atopic individuals protecting against the development of brain tumours. Alternative explanations might include bias, reverse causality or confounding.

Cellular localisation of taurine in the organ of Corti.

The cellular localisation of taurine in the organ of Corti has been established using a monoclonal antibody and confocal fluorescence microscopy. The bulk of the taurine was found in the outer hair cells with very little present in the inner hair cells and supporting structures. The outer hair cells which probably function as an amplification/attenuation gain system, control inner hair cell output to the brain. Taurine is tentatively postulated as being related to calcium fluxes involved in outer hair cell response to sound or olivocochlear bundle stimulation. Other possibilities are also discussed.

Improving information for nuclear medicine department outpatients.

In two large inner city hospitals we have conducted a survey of the letters sent to patients before their attendance at a nuclear medicine department. The majority of questions asked for a graded answer (poor, fair, ok, good, excellent). Patients were handed the survey form when they had completed their test and the survey was continued until 100 valid replies had been received at each hospital. Information leaflets, as recommended by the British Nuclear Medicine Society (BNMS), were subsequently issued to all patients and at one hospital the patient information letters were rewritten. The surveys were then repeated. There was a significant (P < 0.001) improvement in patient satisfaction with the information provided. In some areas, for example, instructions about getting to the hospital, no different information was provided and there was no change between the surveys, as would be expected. Curiously, questions allowing free text answers were more often completed by patients from Dudley Road Hospital, Birmingham, than from Guy's Hospital, London. Some possible explanations for this difference are discussed. Particularly reassuring was that more women understood about precautions regarding pregnancy or breastfeeding as a result of the leaflets. We would recommend the advice of the BNMS to other nuclear medicine departments.

The radiation dose to accompanying nurses, relatives and other patients in a nuclear medicine department waiting room.

The radiation dose to accompanying nurses, relatives and other patients in a nuclear medicine department waiting room was assessed at 5 min intervals by observing the seating arrangement. The total radiation dose to each person was calculated, using fixed values of dose rate per 100 MBq activity for radionuclides, and applying the inverse square law. Radioactive decay and attenuation effects due to intervening persons were also taken into account. The median radiation doses to accompanying nurses, relatives and other patients were 2.3, 2.0 and 0.2 microSv with maximum values of 17, 33 and 5 microSv respectively. In all cases, the radiation dose received by patients was less than 0.2% of the radiation dose resulting from their own investigation. Also, the maximum radiation dose received by an accompanying nurse or friend was less than 1% of their appropriate annual dose limit. Similar values were obtained with calculations based on a 15 min time interval. The radiation doses received by those in a nuclear medicine department waiting room are small, and separate waiting room facilities for radioactive patients are unnecessary.

Breastfeeding and risk of childhood CNS tumours.

We investigated infant feeding habits in relation to risk of childhood central nervous system tumours among 633 cases in the UK Childhood Cancer Study (UKCCS). No significant effect of breastfeeding was detected overall (odds ratio 1.01, confidence interval: 0.85-1.21) nor in any morphological subgroup. Similarly, no effect for the duration of breastfeeding or any other feeding practices was observed.