Acute metabolic responses to a 24-h ultra-marathon race in male amateur runners

The study was conducted to evaluate the metabolic responses to a 24 h ultra-endurance race in male runners. Paired venous and capillary blood samples from 14 athletes (mean age 43.0 ± 10.8 years, body weight 64.3 ± 7.2 kg, VO_2max 57.8 ± 6.1 ml kg⁻¹ min⁻¹), taken 3 h before the run, after completing the marathon distance (42.195 km), after 12 h, and at the finish of the race, were analyzed for blood morphology, acid–base balance and electrolytes, lipid profile, interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP), and serum enzyme activities. Mean distance covered during the race was 168.5 ± 23.1 km (range 125.2–218.5 km). Prolonged ultra-endurance exercise triggered immune and inflammatory responses, as evidenced by a twofold increase in total leukocyte count with neutrophils and monocytes as main contributors, nearly 30-fold increase in serum IL-6 and over 20-fold rise in hsCRP. A progressive exponential increase in mean creatine kinase activity up to the level 70-fold higher than the respective pre-race value, a several fold rise in serum activities of aspartate aminotransferase and alanine aminotransferase, and a fairly stable serum γ-glutamyl transferase level, were indicative of muscle, but not of liver damage. With duration of exercise, there was a progressive development of hyperventilation-induced hypocapnic alkalosis, and a marked alteration in substrate utilization towards fat oxidation to maintain blood glucose homeostasis. The results of this study may imply that progressive decline in partial CO₂ pressure (hypocapnia) that develops during prolonged exercise may contribute to increased interleukin-6 production.     

血卟啉对人胰腺癌细胞Panc-1的光动力作用及机制

目的: 研究光敏剂血卟啉的光动力作用对人胰腺癌细胞Panc-1的体外杀伤效应及其主要机制。方法: 将光敏剂浓度和光照剂量2个因素按不同水平分组,以CCK-8实验的吸光度值为检测指标并转换为细胞存活率,研究这2个因素对光动力作用的影响及其规律。在此基础上,先后以荧光显微镜、流式细胞仪、Western blotting测定这一过程中细胞内活性氧的水平、细胞坏死及凋亡比率以及caspase-3蛋白的表达,探讨光动力作用的主要机制。结果: 随着光敏剂浓度和光照剂量的增加,光动力治疗(PDT)后Panc-1细胞存活率相应下降,并分别在光敏剂浓度10 mg/L、光照剂量20 J/cm²达到最大杀伤效应。光敏剂浓度和光照剂量之间对降低细胞存活率有协同作用。单独给予光敏剂和光照均不对细胞存活率产生影响。PDT作用可使 Panc-1细胞内产生活性氧,并随光敏剂浓度和光照剂量的增加而增多。PDT后细胞出现凋亡和坏死,二者比例随光敏剂浓度和光照剂量的增加而增加,但始终表现为凋亡率＞坏死率。PDT使细胞内caspase-3表达增强,并随光敏剂浓度和光照剂量的增加而增加。结论: 血卟啉光动力治疗对人胰腺癌细胞株Panc-1具有明确的杀伤作用,但是光敏剂和激光照射本身并不具有独立的杀伤效应。光敏剂浓度和光照剂量2个影响因素在一定范围内与PDT效应之间呈正相关的关系,二者之间存在协同作用。PDT的作用机制主要在于其产生的各种活性氧成分,通过各种途径激活caspase-3,最终导致细胞凋亡。     

人结肠癌细胞系SP细胞microRNA表达谱的初步分析

 目的：探讨结肠癌侧群（SP）细胞在结肠癌多药耐药性中的作用及其microRNA生物标志。方法：结肠癌SP细胞的分选采用流式细胞术,细胞活力的测定采用MTT法,microRNA表达谱的检测采用microRNA芯片,microRNA表达的验证采用实时荧光定量PCR。结果：（1）HCT-15、HT-29及LoVo结肠癌细胞系中SP细胞的比例分别为16.75%、13.02%及9.52%。（2） 化疗药（5-氟尿嘧啶、草酸铂及阿霉素）对3种结肠癌细胞系SP细胞的 IC50均明显高于对非SP细胞的IC50（P<0.05）。（3）microRNA芯片检测表明miR-5000-3p、miR-5009-3p及miR-552在3种结肠癌细胞系的SP细胞中表达均上调,实时荧光定量PCR亦证实此结果。结论：miR-5000-3p、miR-5009-3p及miR-552在结肠癌细胞系的SP细胞中表达上调,有可能成为结肠癌SP细胞的潜在microRNA生物标志。     

Immunopolarization of CD4+ and CD8+ T cells to Type-1-like is associated with melanocyte loss in human vitiligo

Vitiligo is an autoimmune condition characterized by loss of epidermal melanocytes. High frequencies of melanocyte-reactive cytotoxic T cells in the peripheral blood of vitiligo patients and the observed correlation between perilesional T-cell infiltration and melanocyte loss in situ suggest the important role of cellular autoimmunity in the pathogenesis of this disease. We isolated T cells from both perilesional and nonlesional skin biopsies obtained from five vitiligo patients, then cloned and analyzed their profile of cytokine production after short-term, nonspecific expansion in vitro. Perilesional T-cell clones (TCC) derived from patients with vitiligo exhibited a predominant Type-1-like cytokine secretion profile, whereas the degree of Type-1 polarization in uninvolved skin-derived TCC correlated with the process of microscopically observed melanocyte destruction in situ. Detailed analysis of broad spectrum of cytokines produced by perilesional- and nonlesional-derived CD4+ and CD8+ TCC confirmed polarization toward Type-1-like in both CD4 and CD8 compartments, which paralleled depigmentation process observed locally in the skin. Furthermore, CD8+ TCC derived from two patients also were analyzed for reactivity against autologous melanocytes. The antimelanocyte cytotoxic reactivity was observed among CD8+ TCC isolated from perilesional biopsies of two patients with vitiligo. Finally, in two of five patients, tetramer analysis revealed presence of high frequencies of Mart-1-specific CD8 T cells in T-cell lines derived from perilesional skin. Altogether our data support the role of cellular mechanisms playing a significant part in the destruction of melanocytes in human autoimmune vitiligo.     

Suicidality in Chinese adolescents in Hong Kong: the role of family and cultural influences

BACKGROUND: Adolescent suicidal ideation has found to predict suicidal behaviors and psychopathology in adulthood. Previous studies focused solely on the medical and environmental risk factors, which were insufficient to give a holistic picture of adolescent suicidality. OBJECTIVES: To assess the role of affective and cognitive attributes in the identification and prevention of adolescent suicidal ideation. METHOD: A community sample of 511 participants (age 15-19 years) were asked to indicate their suicidality in the 12 months and in their lifetime. Generalized estimating equation regression models were used to examine the effect of psychosocial and socio-environmental correlates in relation to adolescent suicidal ideation. RESULTS: The data show that perceived responsibilities for family was the only protective factor, while a coping mechanism by behavioral disengagement, severity of depressive symptoms, a history of deliberate self-harm, chronic physical illness or pain, media reporting of suicide news, and low household income were the risk factors for adolescent suicidal ideation. CONCLUSIONS: The results suggest that a multilayer effort for preventing adolescent suicide is needed by providing support for children in deprived families; enhancing life skills in the teens; strengthening family relationship; improving mental and health services; and promoting responsible media reporting on suicide.     

Pathway to care for postnatal depression after implementation of the Comprehensive Child Development Service in a regional hospital in Hong Kong

Introduction: The Comprehensive Child Development Service (CCDS) launched in Hong Kong in 2005 aimed to identify and manage postnatal depression early. Under the CCDS, postnatal women are screened routinely for depression with the Edinburgh Postnatal Depression Scale. The purpose of the present study was to investigate the pathway to care for postnatal depression after the implementation of CCDS. Methods: During the period from July 2008 to December 2008, 114 Chinese women with postnatal depression were recruited from a perinatal out‐patient psychiatrist clinic which received referrals from the “CCDS route” and the “conventional route”. The participants were interviewed by a semi‐structured questionnaire for their pathway to care, including the duration of untreated depression (DUD) and the carers from whom they sought help for postnatal depression. All the participants were assessed by the Beck Depression Inventory (BDI) and the Global Assessment of Functioning (GAF) scale. Results: Sixty‐six percent of the participants were referred to the clinic through the “CCDS route” and 34% through the “conventional route”. As compared with the CCDS referral group, the conventional group had significantly longer DUD (U [N=114]=446.00, P=0.000), higher BDI score (U [N=114]=393.50, P=0.000) and lower GAF score (U [N=114]=462.50, P=0.000). Discussion: CCDS was found to be associated with the early intervention of postnatal depression.