Validity and reliability of the Chinese critical thinking disposition inventory

2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Anti-Stress Effects of Carnosine on Restraint-Evoked Immunocompromise in Mice through Spleen Lymphocyte Number Maintenance

Carnosine (β-alanyl-L-histidine), a naturally occurring dipeptide, has been characterized as a putative neurotransmitter and serves as a reservoir for brain histamine, which could act on histaminergic neurons system to relieve stress-induced damages. However, understanding of the role of carnosine in stress-evoked immunocompromise is limited. In this study, results showed that when mice were subjected to restraint stress, spleen index and the number of spleen lymphocytes including Natural Killer (NK) cells were obviously decreased. Results also demonstrated that restraint stress decreased the cytotoxic activity of NK cells per spleen (LU10/spleen) while the activity of a single NK cell (LU10/106 cells) was not changed. However, oral administration of carnosine (150 and 300 mg/kg) increased spleen index and number of spleen lymphocytes (including NK cells), and elevated the cytotoxic activity of NK cells per spleen in restraint-stressed mice. These results indicated that carnosine ameliorated stress-evoked immunocompromise through spleen lymphocyte number maintenance. Carnosine was further found to reduce stress-induced elevation of plasma corticosterone level. On the other hand, results showed that carnosine and RU486 (a glucocorticoids receptor antagonist) treatment prevented the reduction in mitochondrion membrane potential and the release of mitochondrial cytochrome c into cytoplasm, increased Bcl-2/Bax mRNA ratio, as well as decreased terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells in spleen lymphocytes of stressed mice. The results above suggested that the maintenance of spleen lymphocyte number by carnosine was related with the inhibition of lymphocytes apoptosis caused by glucocorticoids overflow. The stimulation of lymphocyte proliferation by carnosine also contributed to the maintenance of spleen lymphocyte number in stressed mice. In view of the elevated histamine level, the anti-stress effects of carnosine on restraint-evoked immunocompromise might be via carnosine-histamine metabolic pathway. Taken together, carnosine maintained spleen lymphocyte number by inhibiting lymphocyte apoptosis and stimulating lymphocyte proliferation, thus prevented immunocompromise in restraint-stressed mice

P3HT-Based Solar Cells: Structural Properties and Photovoltaic Performance

Each year we are bombarded with B.Sc. and Ph.D. applications from students that want to improve the world. They have learned that their future depends on changing the type of fuel we use and that solar energy is our future. The hope and energy of these young people will transform future energy technologies, but it will not happen quickly. Organic photovoltaic devices are easy to sketch, but the materials, processing steps, and ways of measuring the properties of the materials are very complicated. It is not trivial to make a systematic measurement that will change the way other research groups think or practice. In approaching this chapter, we thought about what a new researcher would need to know about organic photovoltaic devices and materials in order to have a good start in the subject. Then, we simplified that to focus on what a new researcher would need to know about poly-3-hexylthiophene:phenyl-C61-butyric acid methyl ester blends (P3HT: PCBM) to make research progress with these materials. This chapter is by no means authoritative or a compendium of all things on P3HT:PCBM. We have selected to explain how the sample fabrication techniques lead to control of morphology and structural features and how these morphological features have specific optical and electronic consequences for organic photovoltaic device applications

Airway obstruction in children with congenital heart disease: Assessment by flexible bronchoscopy

We assessed the spectrum of airway disorders in children with congenital cardiac anomalies, and reviewed our experience in using flexible bronchoscopy for assessment of airway problems in this patient group. The clinical records, flexible bronchoscopic findings, and cardiac imaging results of pediatric cardiac patients who presented with either clinical or radiological signs of airway obstruction between 1992-1999 were reviewed. Frexible bronchoscopic assessment was performed with the patients under sedation and topical anesthesia, using one of two bronchoscopes, i.e., an Olympus BFN20 or Olympus BF3C20. Of a total of 52 patients, 33 had acyanotic cardiovascular lesions, the commonest being left-to-right shunts (61%), while 19 had cyanotic heart lesions, with right ventricular outflow obstruction being the commonest (63%). Twenty-seven patients had undergone either surgical or transcatheter interventions. The median age at bronchoscopic assessment was 6 months (range, 4 days to 6 years). None of the patients developed significant procedural complications. A definitive diagnosis was made in 48 (92%) patients, 8 of whom had abnormalities involving only the upper airways, 35 only the lower airways, and 5 both. Abnormalities of the upper airway included laryngomalacia (n = 6), subglottic stenosis (n = 3), pharyngeal collapse (n = 2), and 1 each of choanal stenosis and supraglottitis. Extrinsic compression was the commonest lower airway abnormality that was found in 27/40 patients (67%), with a predilection for the left main bronchus (18/27, 67%). The structures that caused extrinsic compression included dilated pulmonary arteries with or without left atrial dilation (n = 20), an anomalous aortic or pulmonary arterial course (n = 3), a dilated aorta (n = 1), and a shunt (n = 1), but were not obvious in 2 patients. Intrinsic lower airway abnormalities included bronchomalacia (n = 4), tracheal stenosis (n = 4), and one each of variant bronchial bifurcation and a pouch arising from the tracheal wall. Intraluminal mucus plugging of the lower airways occurred in the remaining 3 patients. Children with congenital heart disease are at risk of airway obstruction both before and after surgery. Flexible bronchoscopy, being safe and effective in diagnosing airway disorders in this patient group, should be considered as the first line of investigation. © 2002 Wiley-Liss, Inc.link_to_subscribed_fulltex

Relation of arterial stiffness with gestational age and birth weight

Background: The cardiovascular risk of individuals who are born small as a result of prematurity remains controversial. Given the previous findings of stiffer peripheral conduit arteries in growth restricted donor twins in twin–twin transfusion syndrome regardless of gestational age, we hypothesised that among children born preterm, only those with intrauterine growth retardation are predisposed to an increase in cardiovascular risks. Aim: To compare brachioradial arterial stiffness and systemic blood pressure (BP) among children born preterm and small for gestational age (group 1, n = 15), those born preterm but having birth weight appropriate for gestational age (group 2, n = 36), and those born at term with birth weight appropriate for gestational age (group 3, n = 35). Methods: Systemic BP was measured by an automated device (Dinamap), while stiffness of the brachioradial arterial segment was assessed by measuring pulse wave velocity (PWV). The birth weight was adjusted for gestational age and expressed as a z score for analysis. Results: The 86 children were studied at a mean (SD) age of 8.2 (1.7) years. Subjects from group 1, who were born at 32.3 (2.0) weeks' gestation had a significantly lower z score of birth weight (-2.29 (0.63), p<0.001), compared with those from groups 2 and 3. They had a significantly higher mean blood pressure (p<0.001) and their diastolic blood pressure also tended to be higher (p = 0.07). Likewise, their brachioradial PWV, and hence arterial stiffness, was the highest of the three groups (p<0.001). While subjects from group 2 were similarly born preterm, their PWV was not significantly different from that of group 3 subjects (p = 1.00) and likewise their z score of birth weight did not differ (-0.01 (0.71) v -0.04 (1.1), p = 1.00). Brachioradial PWV correlated significantly with systolic (r = 0.31, p = 0.004), diastolic (r = 0.38, p<0.001), and mean (0.47, p<0.001) BP, and with z score of birth weight (r = -0.43, p<0.001). Multiple linear regression identified mean BP and z score of birth weight as significant determinants of PWV. Conclusion: The findings of the present study support the hypothesis that among children born preterm, only those with intrauterine growth retardation are disadvantaged as a result of increase in systemic arterial stiffness and mean blood pressure