Aircraft and road traffic noise and children's cognition and health: a cross-national study

BACKGROUND

Exposure to environmental stressors can impair children's health and their cognitive development. The effects of air pollution, lead, and chemicals have been studied, but there has been less emphasis on the effects of noise. Our aim, therefore, was to assess the effect of exposure to aircraft and road traffic noise on cognitive performance and health in children.

METHODS

We did a cross-national, cross-sectional study in which we assessed 2844 of 3207 children aged 9-10 years who were attending 89 schools of 77 approached in the Netherlands, 27 in Spain, and 30 in the UK located in local authority areas around three major airports. We selected children by extent of exposure to external aircraft and road traffic noise at school as predicted from noise contour maps, modelling, and on-site measurements, and matched schools within countries for socioeconomic status. We measured cognitive and health outcomes with standardised tests and questionnaires administered in the classroom. We also used a questionnaire to obtain information from parents about socioeconomic status, their education, and ethnic origin.

FINDINGS

We identified linear exposure-effect associations between exposure to chronic aircraft noise and impairment of reading comprehension (p=0.0097) and recognition memory (p=0.0141), and a non-linear association with annoyance (p<0.0001) maintained after adjustment for mother's education, socioeconomic status, longstanding illness, and extent of classroom insulation against noise. Exposure to road traffic noise was linearly associated with increases in episodic memory (conceptual recall: p=0.0066; information recall: p=0.0489), but also with annoyance (p=0.0047). Neither aircraft noise nor traffic noise affected sustained attention, self-reported health, or overall mental health.

INTERPRETATION

Our findings indicate that a chronic environmental stressor-aircraft noise-could impair cognitive development in children, specifically reading comprehension. Schools exposed to high levels of aircraft noise are not healthy educational environments.

Human sealpox resulting from a seal bite: confirmation that sealpox virus is zoonotic

The case of a marine mammal technician who sustained a seal-bite to the hand that produced a lesion clinically very similar to orf is described. Sequence analysis of the viral DNA amplified from the lesion by the polymerase chain reaction indicated that it was sealpox virus in origin. This is the first report providing unequivocal evidence that sealpox may be transmitted to humans and causes lesions very similar to orf.

A model for cardiopulmonary bypass redesign

INTRODUCTION

A portion of patients undergoing cardiac surgery may develop focal and/or subtle brain injuries secondary to cardiac surgery. There is evidence that, in some cases, these injuries may be related to cardiopulmonary bypass (CPB). Embolism and hypoperfusion are the dominant mechanisms for focal neurologic injuries among coronary artery bypass graft (CABG) surgery patients. Recent studies suggest that these mechanisms may also produce the more prevalent subtle neurological deficits. The aim of our current work is to obtain a thorough understanding of the processes of care associated with the production of embolic activity, cerebral hypoperfusion, and hemodynamic aberrations that often occur during CPB.

METHODS

We developed a system for simultaneous recording of physiologic parameters, embolic activity in the CPB circuit and in the cerebral arteries, and near infrared regional cerebral oxyhemoglobin saturation (NIRS) during cardiac surgery. All data were synchronized with a video recording of the surgical procedure. Periods of embolic activity and NIRS were subsequently related to surgical and CPB processes of care through a systematic review of the patient's surgical case video.

RESULTS

To date, we have enrolled 47 patients undergoing coronary and/or valvular procedures. We have observed wide variation across patients in detected cerebral embolic counts, NIRS and physiologic parameters. We have identified increased embolic counts in the CPB circuit related to specific processes and events such as the method of venous drainage, the entrainment of air in the venous line, the injection of medications into the CPB circuit and blood sampling from the CPB circuit. A portion of detected changes in NIRS were related to periods of hypotension and positioning of the heart during the construction of distal coronary artery grafts on the posterior coronary artery vessels.

SUMMARY

Use of this model provides the surgical team with detailed information regarding the contribution of CPB to the creation of precursors of neurological injury. This system provides meaningful data to guide the surgical team in the redesign of the CPB system and associated techniques.

An international outbreak of salmonellosis associated with raw almonds contaminated with a rare phage type of Salmonella enteritidis

During the winter of 2000 to 2001, an outbreak due to Salmonella Enteritidis (SE) phage type 30 (PT30), a rare strain, was detected in Canada. The ensuing investigation involved Canadian and American public health and food regulatory agencies and an academic research laboratory. Enhanced laboratory surveillance, including phage typing and pulsed-field gel electrophoresis, was used to identify cases. Case questionnaires were administered to collect information about food and environmental exposures. A case-control study with 16 matched case-control pairs was conducted to test the hypothesis of an association between raw whole almond consumption and infection. Almond samples were collected from case homes, retail outlets, and the implicated processor, and environmental samples were collected from processing equipment and associated farms for microbiological testing. One hundred sixty-eight laboratory-confirmed cases of SE PT30 infection (157 in Canada, 11 in the United States) were identified between October 2000 and July 2001. The case-control study identified raw whole almonds as the source of infection (odds ration, 21.1; 95% confidence interval, 3.6 to infinity). SE PT30 was detected in raw whole natural almonds collected from home, retail, distribution, and warehouse sources and from environmental swabs of processing equipment and associated farmers' orchards. The frequent and prolonged recovery of this specific organism from a large agricultural area was an unexpected finding and may indicate significant diffuse contamination on these farms. Identification of almonds as the source of a foodborne outbreak is a previously undocumented finding, leading to a North American recall of this product and a review of current industry practices.

Gene expression during formation of earlywood and latewood in loblolly pine: expression profiles of 350 genes

The natural variability of wood formation in trees affords opportunities to correlate transcript profiles with the resulting wood properties. We have used cDNA microarrays to study transcript abundance in developing secondary xylem of loblolly pine (Pinus taeda) over a growing season. The cDNAs were selected from a collection of 75 000 ESTs that have been sequenced and annotated (http://web.ahc.umn.edu/biodata/nsfpine/). Cell wall thickness and climatic data were related to earlywood and latewood formation at different time points during the growing season. Seventy-one ESTs showed preferential expression in earlywood or latewood, including 23 genes with no significant similarity to genes in GenBank. Seven genes involved in lignin synthesis were preferentially expressed in latewood. The studies have provided initial insights into the variation of expression patterns of some of the genes related to the wood formation process.

MRI and CSF studies in the early diagnosis of Alzheimer's disease

The main goal of our studies has been to use MRI, FDG-PET, and CSF biomarkers to identify in cognitively normal elderly (NL) subjects and in patients with mild cognitive impairment (MCI), the earliest clinically detectable evidence for brain changes due to Alzheimer's disease (AD). A second goal has been to describe the cross-sectional and longitudinal interrelationships amongst anatomical, CSF and cognition measures in these patient groups. It is now well known that MRI-determined hippocampal atrophy predicts the conversion from MCI to AD. In our summarized studies, we show that the conversion of NL subjects to MCI can also be predicted by reduced entorhinal cortex (EC) glucose metabolism, and by the rate of medial temporal lobe atrophy as determined by a semi-automated regional boundary shift analysis (BSA-R). However, whilst atrophy rates are predictive under research conditions, they are not specific for AD and cannot be used as primary evidence for AD. Consequently, we will also review our effort to improve the diagnostic specificity by evaluating the use of CSF biomarkers and to evaluate their performance in combination with neuroimaging. Neuropathology studies of normal ageing and MCI identify the hippocampal formation as an early locus of neuronal damage, tau protein pathology, elevated isoprostane levels, and deposition of amyloid beta 1-42 (Abeta42). Many CSF studies of MCI and AD report elevated T-tau levels (a marker of neuronal damage) and reduced Abeta42 levels (possibly due to increased plaque sequestration). However, CSF T-tau and Abeta42 level elevations may not be specific to AD. Elevated isoprostane levels are also reported in AD and MCI but these too are not specific for AD. Importantly, it has been recently observed that CSF levels of P-tau, tau hyperphosphorylated at threonine 231 (P-tau231) are uniquely elevated in AD and elevations found in MCI are useful in predicting the conversion to AD. In our current MCI studies, we are examining the hypothesis that elevations in P-tau231 are accurate and specific indicators of AD-related changes in brain and cognition. In cross-section and longitudinally, our results show that evaluations of the P-tau231 level are highly correlated with reductions in the MRI hippocampal volume and by using CSF and MRI measures together one improves the separation of NL and MCI. The data suggests that by combining MRI and CSF measures, an early (sensitive) and more specific diagnosis of AD is at hand. Numerous studies show that neither T-tau nor P-tauX (X refers to all hyper-phosphorylation site assays) levels are sensitive to the longitudinal progression of AD. The explanation for the failure to observe longitudinal changes is not known. One possibility is that brain-derived proteins are diluted in the CSF compartment. We recently used MRI to estimate ventricular CSF volume and demonstrated that an MRI-based adjustment for CSF volume dilution enables detection of a diagnostically useful longitudinal P-tau231 elevation. Curiously, our most recent data show that the CSF isoprostane level does show significant longitudinal elevations in MCI in the absence of dilution correction. In summary, we conclude that the combined use of MRI and CSF incrementally contributes to the early diagnosis of AD and to monitor the course of AD. The interim results also suggest that a panel of CSF biomarkers can provide measures both sensitive to longitudinal change as well as measures that lend specificity to the AD diagnosis.

Treatment of superficial cutaneous vascular lesions: experience with the KTP 532�nm laser

Whilst most facial telangiectasias respond well to short-pulse-duration pulsed dye laser therapy, studies have shown that for the treatment of larger vessels these short-duration pulses are sub-optimal. Long-pulse frequency-doubled neodymium:YAG lasers have been introduced with pulse durations ranging from 1-50 ms and treatment beam diameters of up to 4 mm. We report the results of KTP/532 nm laser treatment for superficial vascular skin lesions. The aim was to determine the efficacy of the KTP/532 nm laser in the treatment of superficial cutaneous vascular lesions at a regional dermatology centre in a 2 year retrospective analysis. Patients were referred from general dermatology clinics to a purpose-built laser facility. A test dose was performed at the initial consultation and thereafter patients were reviewed and treated at 6 week intervals. Outcome was graded into five classifications by the patient and operator independently based on photographic records: clear, marked improvement, partial response, poor response, and no change or worsening. Over the 2 year period, 204 patients with 246 diagnoses were treated [156 female; median age 41 (range 1-74) years; Fitzpatrick skin types I-III]. Equal numbers of spider angioma (102) and facial telangiectasia (102) were treated. Of those patients who completed treatment and follow up, 57/58 (98%) of spider angiomas and 44/49 (90%) of facial telangiectasia markedly improved or cleared. Satisfactory treatment outcomes, with one clearance and two partial responses, occurred in three of five patients with port-wine stain. Few patients experienced adverse effects: two declined further treatment due to pain, and a small area of minimal superficial scarring developed in one case. Two patients developed mild persistent post-inflammatory hyperpigmentation, and one subject experienced an episode of acute facial erythema, swelling and blistering after one treatment. The KTP/532 nm frequency-doubled neodymium:YAG laser is a safe and effective treatment for common superficial cutaneous vascular lesions in patients with Fitzpatrick skin types I-III.

Scalp necrosis in temporal arteritis

Giant cell arteritis is a systemic disease of the elderly which affects large and medium-sized arteries and which may occur in association with polymyalgia rheumatica. Scalp necrosis is a rare cutaneous complication of giant cell arteritis, and this dermatological presentation is not commonly reported.1-4 Giant cell arteritis should be considered in all elderly patients with scalp ulceration. We describe two patients who presented in this manner.

Brain metabolism in the cerebellum and visual cortex correlates with neuropsychological testing in patients with Alzheimer's disease

This study was designed to measure glucose metabolic deficits in areas not typically recognized as abnormal on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans in patients with Alzheimer's disease (AD), and to correlate such findings with subtle neuropsychological impairment. FDG-PET scans on 38 AD patients with no clinical evidence of visual, spatial or motor deficits were acquired on the PET HEAD scanner 40 min following the intravenous administration of 115 microCi.kg-1 of FDG. All FDG-PET scans were analysed blindly using a region of interest (ROI) template with regions for the primary visual cortex (PVC), secondary visual cortex (SVC) and cerebellum. Counts from the ROIs of these regions were normalized to whole brain activity and the results were compared with psychometric and neuropsychological measures. A number of significant correlations were found between these structures and various neuropsychological measures (P<0.05). Specifically, there were significant correlations between clock drawing and the cerebellum activity; memory and activity in the PVC, SVC and cerebellum; social score and activity in the PVC and left cerebellum; judgement and activity in the right SVC and right PVC; and the overall Mini-Mental State Examination and activity in the PVC, SVC and cerebellum. The results of this study suggest that metabolism in areas not typically recognized as abnormal on FDG-PET scans in AD, such as the PVC, SVC and cerebellum, is correlated with deficits in neuropsychological function. This may have important clinical and pathophysiological implications in the study of AD and other illnesses of dementia.

Topical 5-aminolaevulinic acid photodynamic therapy for cutaneous lesions: outcome and comparison of light sources

BACKGROUND

Topical 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) is increasingly used for superficial non-melanoma skin cancers and their precursors.

METHODS

We report our 3-year experience of topical ALA-PDT, with a preliminary comparison of the effects of broadband and laser light sources.

RESULTS

We performed 688 treatments on 483 lesions in 207 patients. Complete clearance was achieved in 222/239 lesions of Bowen's disease (BD), superficial basal cell carcinoma (sBCC) and actinic keratosis (AK) (93%) - 117/129 BD (91%), 84/87 sBCC (97%) and 21/23 AK (91%), with a median follow up of 48 weeks. Broadband and laser light sources were of similar efficacy. Recurrences have occurred in 10.3% BD, 4.8% sBCC and 4.8% AK. Adverse effects from PDT were uncommon but included pigmentary change (2%) and minor scarring (2%). How-ever, severe pain was experienced in 16-21% of treatments using the high-output broadband and laser sources, but in only 2% with the low-output xenon arc source.

CONCLUSION

Topical ALA-PDT is effective for BD, sBCC and AK and has been an invaluable addition to our dermatology service. Efficacy is similar for broadband and laser light sources, although treatment at higher surface irradiance may be painful, and excellent cosmetic results can be achieved.

CYP3A4 and VDR gene polymorphisms and the risk of prostate cancer in men with benign prostate hyperplasia

Prostate cancer (PRCa) is one of the most common causes of cancer death in men and determinants of PRCa risk remain largely unidentified. Benign prostatic hyperplasia (BPH) is found in the majority of ageing men and has been associated with PRCa. Many candidate genes have been suggested to be involved in PRCa, such as those that are central to cellular growth and differentiation in the prostate gland. The vitamin D receptor (VDR) and CYP3A4 have been shown to be involved in the regulation of cell proliferation and differentiation in prostate cells. Genetic variations of these genes have been associated with PRCa in case-control studies and may be useful to detect BPH patients that have a higher risk of developing PRCa. The association between CYP3A4 and VDR TaqI SNPs and the risk of developing PRCa have been investigated in this study by determining the variant genotype frequencies of both SNPs in 400 patients with BPH who have been followed clinically for a median of 11 years. The results of this study showed that the incidence rate of PRCa was higher in BPH patients having CYP3A4 variant genotype compared to those with wild type (relative risk (RR)=2.7; 95% CI=0.77-7.66). No association between variant genotype and risk of developing PRCa was observed with the VDR TaqI variant genotype. In addition, the results of combined genotype analysis of these two SNPs showed a borderline significant association between CYP3A4 and VDR TaqI combined variant genotypes and PRCa risk (RR=3.43; 95% CI=0.99-11.77). While independent confirmation is required in further studies, these results provide a potential tool to assist prediction strategies for this important disease.

Cu, Cr and As distribution in soils adjacent to pressure-treated decks, fences and poles

Chromated copper arsenate (CCA)-treated wood has been widely used in the Southeastern United States to protect wood products from microbial and fungal decay. The aims of this study were to (1). determine the distribution of arsenic (As), chromium (Cr), and copper (Cu), in soils surrounding CCA-treated wood structures such as decks, fences and poles; and (2). evaluate the impacts of these structures on As, Cr and Cu loading of the soils. Profile and lateral soil samples were collected under CCA-treated decks and adjacent to poles and fences. The results showed elevation of As, Cr and Cu concentrations close to and under the structures, with mean As concentrations as high as 23 mg x kg(-1) close to utility poles compared with less than 3 mg x kg (-1) at distances of about 1.5 m away. Concentrations of As, Cr, and Cu decreased with depth in areas close to CCA-treated poles. However, these results were only apparent in relatively new structures. A combination of weathering and leaching with time may have reduced the impact in older poles. Increased concentrations of As, Cu and Cr were also observed close to CCA-treated decks and fences, with age showing a similar impact. These results are helpful for CCA-treated wood product users to determine the safe use of these structures.

Evaluation of the epidermal growth factor receptor (EGFR) in colorectal tumours and lymph node metastases

Overexpression of the epidermal growth factor receptor (EGFR) often correlates with an aggressive tumour phenotype and poor prognosis. To examine the relevance of EGFR in colorectal cancer, we determined the expression of EGFR protein in 249 colorectal adenocarcinomas and 42 lymph node metastases using immunohistochemistry. Moreover, we investigated a (CA)(n) dinucleotide repeat polymorphism of the EGFR gene in a subset of 114 tumours. High levels of EGFR protein were observed in 123/249 (49.4%) samples. EGFR expression in colorectal carcinomas correlated with differentiation grade (P=0.014). However, there were no associations with Dukes' stage, site, patient age or gender. EGFR protein expression did not influence survival in this colorectal cancer patient cohort (P>or=0.05). Expression was not identical in paired colorectal tumours and lymph node metastases, with only 17/42 (40.5%) samples showing equivalent EGFR levels (P>0.05). The distribution of the (CA)(n) dinucleotide repeat alleles in colorectal adenocarcinomas was not associated with EGFR protein expression (P>0.05). These results indicate that while EGFR overexpression is a common event in colorectal carcinogenesis, it does not influence patient prognosis.

Distortion correction and robust tensor estimation for MR diffusion imaging

This paper presents a new procedure to estimate the diffusion tensor from a sequence of diffusion-weighted images. The first step of this procedure consists of the correction of the distortions usually induced by eddy-current related to the large diffusion-sensitizing gradients. This correction algorithm relies on the maximization of mutual information to estimate the three parameters of a geometric distortion model inferred from the acquisition principle. The second step of the procedure amounts to replacing the standard least squares-based approach by the Geman-McLure M-estimator, in order to reduce outlier-related artefacts. Several experiments prove that the whole procedure highly improves the quality of the final diffusion maps.

Sleep deprivation as a model experimental antidepressant treatment: findings from functional brain imaging

This paper reviews the functional brain imaging studies in depressed patients treated with sleep deprivation. Sleep deprivation is an excellent experimental model of antidepressant treatments which offer new opportunities to understand the basic neural mechanisms. Its antidepressant effects are efficacious and rapid; sleep deprivation is easy to administer, inexpensive, and relatively safe; it can be studied in patients, normal controls, and animals; and it may lead to new treatments and new paradigms for antidepressant therapies. Seven published papers, coming from five different research centers, using either positron emission tomography (PET) with 18fluorodeoxyglucose (FDG) or single photon emission computerized tomography (SPECT) with Technetium-99-bexamethyl propyleneamine oxime (HMPAO) have relatively consistent findings. First, before sleep deprivation, responders have significantly elevated metabolism compared with non-responders, and usually the normal controls, in the orbital medial prefrontal cortex, and especially in the ventral portions of the anterior cingulate cortex. Secondly, after sleep deprivation, these hyperactive areas normalize in the responders. The magnitude of the clinical improvement was significantly correlated with decreased local glucose metabolic rate or cerebral blood flow in three studies. The results are consistent with some but not all functional brain imaging studies of antidepressant medications in depressed patients. Finally, a SPECT study using a radioactively labeled D2 receptor antagonist suggests that the antidepressant benefits of sleep deprivation are correlated with endogenous release of dopamine.