Association of ambient air‐pollution levels with acute asthma exacerbation among children in Singapore

BACKGROUND: Air-pollution levels have been shown to be associated with increased morbidity of respiratory diseases. METHODS: Data for ambient air-pollutant levels, meteorologic factors, and hospitalization or emergency room (ER) visits for acute asthma in Singapore children over a 5-year period (1990-4) were obtained and analyzed for associations by time-series methods. RESULTS: Throughout this period, the annual mean and 24-h mean levels for sulfur dioxide (SO2), nitrogen dioxide (NO2), and total suspended particles (TSP) and maximum 1-h daily average for ozone were generally within the air-quality guidelines established by the World Health Organization (WHO). However, positive correlation between levels of each of these pollutants and daily ER visits for asthma was observed in children aged 3-12 years, but not among adolescents and young adults (13-21 years old). The association with SO2 and TSP persisted after standardization for meteorologic and temporal variables. An adjusted increase in 2.9 ER visits for every 20 microg/m3 increase in atmospheric SO2 levels, lagged by 1 day, was observed on days when levels were above 68 microg/m3. With TSP, an adjusted increase of 5.80 ER visits for every 20 microg/m3 increase in its daily atmospheric levels, lagged by 1 day, was observed on days with levels above 73 microg/m3. Similar results were also obtained after controlling for autocorrelation by time-series analysis. CONCLUSIONS: These associations were observed even though the overall levels of all pollutants were generally within the air-quality guidelines established by the WHO. These findings suggest that asthmatic children are susceptible to increased levels of air pollutants, particularly SO2 and TSP, although the ambient levels are generally within "acceptable" ranges.     

Fibrin-polyurethane composites for articular cartilage tissue engineering: a preliminary analysis

In this study we investigated the use of a fibrin hydrogel to improve the potential of a polyurethane (PU) scaffold-based system for articular cartilage tissue engineering. PU-only ("no-fibrin") and PU-fibrin ("fibrin") composites were cultured for up to 28 days and analyzed for DNA content, glycosaminoglycan (GAG) content, type II collagen content, GAG release, and gene expression of aggrecan, collagen I, and collagen II. The use of fibrin allowed for higher viable cell-seeding efficiency (10% higher DNA content on day 2 in fibrin versus no-fibrin composites) and more even cell distribution on seeding, a more than 3-fold increase in the percentage of newly synthesized GAG retained in the constructs, and 2- to 6-fold higher levels of type II collagen and aggrecan gene expression through day 14. Addition of aprotinin to the medium inhibited fibrin degradation, most noticeably in the center of the constructs, but had little effect on biochemical composition or gene expression. Short-term mechanical compression (0-10% sinusoidal strain at 0.1 Hz for 1 h, applied twice daily for 3 days) doubled the rate of GAG release from the constructs, but had little effect on gene expression, regardless of the presence of fibrin. Although further work is needed to optimize this system, the addition of fibrin hydrogel to encapsulate cells in the stiff, macroporous PU scaffold is a step forward in our approach to articular cartilage tissue engineering.     

Laser-ultraviolet-A-induced ultraweak photon emission in mammalian cells

Photobiological research in the last 30 yr has shown the existence of ultraweak photon emission in biological tissue, which can be detected with sophisticated photomultiplier systems. Although the emission of this ultraweak radiation, often termed biophotons, is extremely low in mammalian cells, it can be efficiently increased by ultraviolet light. Most recently it was shown that UV-A (330 to 380 nm) releases such very weak cell radiation in differentiated human skin fibroblasts. Based on these findings, a new and powerful tool in the form of UV-A-laser-induced biophotonic emission of cultured cells was developed with the intention to detect biophysical changes between carcinogenic and normal cells. With suspension densities ranging from 1 to 8 x 10(6) cells/mL, it was evident that an increase of the UV-A-laser-light induced photon emission intensity could be observed in normal as well as melanoma cells. Using this new detection procedure of ultraweak light emission, photons in cell suspensions as low as 100 microL could be determined, which is a factor of 100 lower compared to previous procedures. Moreover, the detection procedure has been further refined by turning off the photomultiplier system electronically during irradiation leading to the first measurements of induced light emission in the cells after less than 10 micros instead of 150 ms, as reported in previous procedures. This improvement leads to measurements of light bursts up 10(7) photons/s instead of several hundred as found with classical designs. Overall, we find decreasing induction ratings between normal and melanoma cells as well as cancer-prone and melanoma cells. Therefore, it turns out that this highly sensitive and noninvasive device enables us to detect high levels of ultraweak photon emission following UV-A-laser-induced light stimulation within the cells, which enables future development of new biophysical strategies in cell research.     

Pulmonary pathological features in coronavirus associated severe acute respiratory syndrome (SARS)

BACKGROUND: Severe acute respiratory syndrome (SARS) became a worldwide outbreak with a mortality of 9.2%. This new human emergent infectious disease is dominated by severe lower respiratory illness and is aetiologically linked to a new coronavirus (SARS-CoV). METHODS: Pulmonary pathology and clinical correlates were investigated in seven patients who died of SARS in whom there was a strong epidemiological link. Investigations include a review of clinical features, morphological assessment, histochemical and immunohistochemical stainings, ultrastructural study, and virological investigations in postmortem tissue. RESULTS: Positive viral culture for coronavirus was detected in most premortem nasopharyngeal aspirate specimens (five of six) and postmortem lung tissues (two of seven). Viral particles, consistent with coronavirus, could be detected in lung pneumocytes in most of the patients. These features suggested that pneumocytes are probably the primary target of infection. The pathological features were dominated by diffuse alveolar damage, with the presence of multinucleated pneumocytes. Fibrogranulation tissue proliferation in small airways and airspaces (bronchiolitis obliterans organising pneumonia-like lesions) in subpleural locations was also seen in some patients. CONCLUSIONS: Viable SARS-CoV could be isolated from postmortem tissues. Postmortem examination allows tissue to be sampled for virological investigations and ultrastructural examination, and when coupled with the appropriate lung morphological changes, is valuable to confirm the diagnosis of SARS-CoV, particularly in clinically unapparent or suspicious but unconfirmed cases.     

Rapid and specific detection of Escherichia coli clonal group A by gene-specific PCR

PCR primers specific for the recently described antimicrobial resistance-associated Escherichia coli clonal group A (CGA), a widespread cause of drug-resistant urinary tract infections in the United States, were devised on the basis of a novel single-nucleotide polymorphism identified within the housekeeping gene fumC, i.e., C288T. In comparison with two reference PCR-based fingerprinting methods, ERIC2 PCR and random amplified polymorphic DNA (RAPD) analysis, a PCR assay incorporating the new primers provided 100% sensitivity and 100% specificity for the detection of CGA among 138 diverse clinical and reference E. coli isolates. E. coli reference (ECOR) strain 47 was shown to be a member or a close relative of CGA (by ERIC2 PCR and RAPD analysis, respectively) and yielded a positive assay result. The new CGA-specific PCR assay, which exhibited interlaboratory reproducibility and stability under various experimental conditions, should allow the rapid and specific detection of CGA by any laboratory equipped for diagnostic PCR.     

The segmented regional volumes of the cerebrum and cerebellum in boys with Tourette syndrome

Neuropathological deficits are an etiological factor in Tourette syndrome (TS), and implicate a network linking the basal ganglia and the cerebrum, not a particular single brain region. In this study, the volumes of 20 cerebral and cerebellar regions and their symmetries were measured in normal boys and TS boys by brain magnetic resonance imaging. Brain magnetic resonance images were obtained prospectively in 19 boys with TS and 17 age-matched normal control boys. Cerebral and cerebellar regions were segmented to gray and white fractions using algorithm for semi-automated fuzzy tissue segmentation. The frontal, parietal, temporal, and the occipital lobes and the cerebellum were defined using the semiautomated Talairach atlas-based parcellation method. Boys with TS had smaller total brain volumes than control subjects. In the gray matter, although the smaller brain volume was taken into account, TS boys had a smaller right frontal lobe and a larger left frontal lobe and increased normal asymmetry (left>right). In addition, TS boys had more frontal lobe white matter. There were no significant differences in regions of interest of the parietal, temporal, or the occipital lobes or the cerebellum. These findings suggest that boys with TS may have neuropathological abnormalities in the gray and the white matter of the frontal lobe.     

Differential involvement of GABA system in mediating behavioral and neurochemical effect of acupuncture in ethanol-withdrawn rats

In our previous study we demonstrated that acupuncture at Shenmen (HT7) points suppressed a decrease of accumbal dopamine (DA) release in ethanol-withdrawn rats. Furthermore, here we found that it inhibited behavioral withdrawal signs of ethanol. In an effort to better understand the mechanisms underlying this inhibition, the potential role of GABA receptor system in acupuncture was investigated. Male Sprague–Dawley rats were treated with 3 g/kg/day of ethanol (20%, w/v) or saline by intraperitoneal injection for 21 days. Following 48 or 72 h of ethanol withdrawal, acupuncture was applied at bilateral HT7 for 1 min. The selective GABA_A antagonist bicuculline and the selective GABA_B antagonist SCH 50911 were injected intraperitoneally 20 min before acupuncture, respectively. Importantly, suppressive effects of acupuncture on DA deficiency were completely abolished by SCH 50911, but not by bicuculline, whereas ameliorating effects of acupuncture on ethanol withdrawal syndrome were completely blocked either by SCH 50911 or bicuculline. These results suggest that acupuncture at specific acupoint HT7 may normalize the DA release in the mesolimbic system and attenuate withdrawal syndrome through the GABA_B receptor system in ethanol-withdrawn rats.     

Web-based Diagnostic Imaging Service Using XML Forms

Traditionally, radiology has been conceived as a support department providing patient scanning services to the other clinical departments in a hospital. However, recent advancements in networking technology and related information systems such as picture archiving and communication system (PACS) and radiology information system (RIS) provide new opportunities for inventing different types of diagnostic imaging businesses such as teleradiology. In this article, we examined the business processes of currently operating imaging centers and proposed a prototype of an information system that can facilitate their workflows in a more efficient way. The principal component of our proposed system is a report management module built on extensible markup language (XML) technologies that allows much flexibility and convenience for both imaging technicians and radiologists.