Impact of asthma and air pollution on school attendance of primary school children: are they at increased risk of school absenteeism?

AIM: The aim of this study was to determine the impact of asthma and air pollution on school attendance of primary school children 6 to 12 years of age in Qatar. STUDY DESIGN: This was a cross-sectional population-based study. SUBJECTS: The total 31,400 Qatari school children at the primary school (16,130 boys and 15,270 girls) 6 to 12 of age were studied to investigate school absenteeism caused by asthma and wheezing during the academic year October 2003 to July 2004. METHODS: We have used the School Health Registry for obtaining the student information and school absenteeism due to asthma and wheezing. Again we had double confirmation on the data obtained on asthmatic children by using the modified version of the International Study of Asthma and Allergies in Childhood [ISAAC] questionnaire. RESULTS: A total of 3,270 (10.4%) pupils were diagnosed as having asthma and wheezing. Overall 2,516 (8.02%) pupils were absent from the school for at least one day during the year. There was a statistically significant difference between asthmatic and wheezing students in number of days absent from the school (p < 0.0001). Most absenteeism occurred during spring for both boys (45%) and girls (47%), followed by autumn for boys (33%) and girls (36%). The measured pollutants reached a peak during the spring season and then in autumn of the studied academic year. CONCLUSION: Children with known asthma miss more days of school than those who do not have asthma. This study finding shows that air pollution has an impact on asthma, which results in significant school absenteeism.     

Strain-specific alterations in consumption of a palatable diet following repeated stressor exposure.

Exposure to acute inescapable shock caused reductions in the consumption of a highly palatable diet. The magnitude and duration of the reduction varied across strains of mice. With repeated exposure to footshock, consumption of the diet returned to baseline levels, although alterations of weight appeared to be more persistent. The course of the adaptation varied across strains of mice; however, the rate of adaptation was unrelated to the extent of the alterations of consumption induced by the acute stressor. When mice were exposed to a series of different stressors, the adaptation progressed less readily, and reductions of diet consumption were apparent in strains that had not shown such an effect following acute stressor application or when repeatedly exposed to a single type of stressor. Data were discussed with respect to the mechanisms that might be operative in subserving stressor-induced anhedonia.     

Operant Conditioning of Heart Rate: Somatic Correlates

The relationships between heart rate (HR) and several parameters of somatic activity were evaluated in human subjects when shuck avoidance was made contingent on either increases or decreases in HR. In order to depict any influence of the contingency specific 10 HR, somatic activity was controlled to varying degrees by instructions and the use of non-contingent control groups. When increases in HR were reinforced, the contingency we found to influence somatic activity but an effect specific to HR was also observed. When decreases in HR were reinforced, there was no evidence that HR were influenced independently of somatic activity. The result are discussed with respect to several current issues.     

Monoclonal antibody purified beta 2-microglobulin: heterogeneity revealed by radioimmunoassay

A monoclonal antibody, CMRF1, to human beta 2-microglobulin (beta 2m) was used to purify antigen to develop an in-house beta 2m radioimmunoassay. This immunoadsorption purified material was used to prepare a rabbit anti-beta 2m serum and was radiolabelled for the radioimmunoassay. The assay compared favourably with a widely used commercial radioimmunoassay but the immunological potency of the in-house standard was lower than that of the commercial reagent. This potency difference was not accounted for by antigenic denaturation. Subsequent two-dimensional gel electrophoresis revealed a second 12,000 dalton protein with a higher isoelectric point than beta 2m in the immunoadsorption purified material, which was also present, although in lesser amounts, in the commercial product. The different relative content of the additional 12,000 dalton protein appeared to explain the immunological potency difference between the in-house and the commercial standard. These results strengthen suggestions that there may be some heterogeneity or polymorphism in human beta 2m.     

Delusions in Alzheimer's disease: spet evidence of right hemispheric dysfunction

Delusional thinking and related behaviours are common symptoms in Alzheimer's disease (AD). The aim of the study was to determine if any consistent cerebral image pattern can be identified using Tc99m-hexamethylpropyleneamine (HMPAO) SPET in AD patients with and without delusions. 18 AD patients with delusion and 15 AD patients without delusion underwent neuropsychological testing and regional cerebral blood flow imaging using Tc99m-HMPAO SPET. The reconstructed data was compared using regions of interest drawn over each cerebral lobe and a statistical parametric mapping (SPM) approach. The neuropsychological testing showed that there was no difference in the profiles of the deluded and non deluded AD patients. The imaging results showed a significant degree of image asymmetry. This took the form of a right hemisphere hypoperfusion mainly in the right frontal and limbic regions. The results do not indicate a specific focal site of hypoperfusion in the patients with delusion. They do, however, indicate that delusions in AD may be associated with areas of hypoperfusion in the right anterior hemisphere.     

Health risks associated with cigar smoking

This article summarizes principal findings from a conference convened by the American Cancer Society in June 1998 to examine the health risks of cigar smoking. State-of-the-science reports were presented and 120 attendees (representing government and private agencies, academia, health educators, and tobacco control experts) participated in panels and summary development discussions. The following conclusions were reached by consensus: (1) rates of cigar smoking are rising among both adults and adolescents; (2) smoking cigars instead of cigarettes does not reduce the risk of nicotine addiction; (3) as the number of cigars smoked and the amount of smoke inhaled increases, the risk of death related to cigar smoking approaches that of cigarette smoking; (4) cigar smoke contains higher concentrations of toxic and carcinogenic compounds than cigarettes and is a major source of fine-particle and carbon monoxide indoor air pollution; and (5) cigar smoking is known to cause cancers of the lung and upper aerodigestive tract. JAMA. 2000;284:735-740     

Isoflurane alters the recirculatory pharmacokinetics of physiologic markers

BACKGROUND: Earlier studies have demonstrated that physiologic marker blood concentrations in the first minutes after administration, when intravenous anesthetics exert their maximum effect, are determined by both cardiac output and its distribution. Given the reported vasodilating properties of isoflurane, we studied the effects of isoflurane anesthesia on marker disposition as another paradigm of altered cardiac output and regional blood flow distribution. METHODS: The dispositions of markers of intravascular space and blood flow (indocyanine green), extracellular space and free water diffusion (inulin), and total body water and tissue perfusion (antipyrine) were determined in four purpose-bred coonhounds. The dogs were studied while awake and while anesthetized with 1.7%, 2.6%, and 3.5% isoflurane (1.15, 1.7, and 2.3 minimum alveolar concentration, respectively) in a randomized order determined by a Latin square experimental design. Marker dispositions were described by recirculatory pharmacokinetic models based on very frequent early, and less frequent later, arterial blood samples. These models characterize the role of cardiac output and regional blood flow distribution on drug disposition. RESULTS: Isoflurane caused a significant and dose-dependent decrease in cardiac output. Antipyrine disposition was profoundly affected by isoflurane anesthesia, during which nondistributive blood flow was maintained despite decreases in cardiac output, and the balance between fast and slow tissue volumes and blood flows was altered. CONCLUSIONS: The isoflurane-induced changes in marker disposition were different than those the authors reported previously for halothane anesthesia, volume loading, or hypovolemia. These data provide further evidence that not only cardiac output but also its peripheral distribution affect early drug concentration history after rapid intravenous administration.