Genotoxicity and physicochemical characteristics of traffic-related ambient particulate matter

Exposure to ambient particulate matter (PM) has been linked to several adverse health effects. Since vehicular traffic is a PM source of growing importance, we sampled total suspended particulate (TSP), PM(10), and PM(2.5) at six urban locations with pronounced differences in traffic intensity. The mutagenicity, DNA-adduct formation, and induction of oxidative DNA damage by the samples were studied as genotoxicological parameters, in relation to polycyclic aromatic hydrocarbon (PAH) levels, elemental composition, and radical-generating capacity (RGC) as chemical characteristics. We found pronounced differences in the genotoxicity and chemical characteristics of PM from the various locations, although we could not establish a correlation between traffic intensity and any of these characteristics for any of the PM size fractions. Therefore, the differences between locations may be due to local sources of PM, other than traffic. The concentration of total (carcinogenic) PAHs correlated positively with RGC, direct and S9-mediated mutagenicity, as well as the induction of DNA adducts and oxidative DNA damage. The interaction between total PAHs and transition metals correlated positively with DNA-adduct formation, particularly from the PM(2.5) fraction. RGC was not associated with one specific PM size fraction, but mutagenicity and DNA reactivity after metabolic activation were relatively high in PM(10) and PM(2.5), when compared with TSP. We conclude that the toxicological characteristics of urban PM samples show pronounced differences, even when PM concentrations at the sample sites are comparable. This implies that emission reduction strategies that take chemical and toxicological characteristics of PM into account may be useful for reducing the health risks associated with PM exposure.     

Increasing trend of Cesarean deliveries in HIV-infected women in the United States from 1994 to 2000

BACKGROUND: Meta-analysis and randomized clinical trial results reported in June 1998 indicated a significant reduction in perinatal HIV transmission rates among mothers undergoing a cesarean section (C-section). OBJECTIVE: The objective of this study was to examine recent trends in and factors associated with C-section deliveries among HIV-infected women in the United States. DESIGN: A multisite pediatric medical record review of a cohort of HIV-exposed and HIV-infected infants in the Pediatric Spectrum of HIV Disease (PSD) Cohort study (n = 6467) and the national Pediatric HIV/AIDS Reporting System (HARS) (n = 8,306) was conducted. SETTING/PATIENTS: All infants born between 1994 and 2000 to HIV-positive mothers referred to the PSD study or to a Pediatric HARS hospital or clinic site were enrolled. RESULTS: The proportion of deliveries by C-section was steady at about 20% from 1994 through June 1998. From July 1998 through December 2000, this proportion increased to 44% in the PSD study and to nearly 50% in the Pediatric HARS. On analysis by multiple logistic regression, delivery of infants by C-section was associated with the release of study results (OR = 2.83), delivery in four PSD sites in reference to Texas (OR: 2.02-1.43), having private medical care reimbursement (OR = 1.62), and having maternal prenatal care (OR = 1.43). CONCLUSIONS: The PSD and Pediatric HARS data demonstrate a sharp increase in C-section rates mainly among HIV-infected women in the United States after the release of the meta-analysis and randomized clinical trial results in 1998. This finding highlights the rapid impact of study results on obstetric practice. It underscores the critical role of prenatal care in offering perinatal interventions such as scheduled C-section when indicated to reduce the likelihood of HIV transmission.     

Selective inhibition by dactinomycin of NANC sensory bronchoconstriction and [125I]NKA binding due to NK-2 receptor antagonism.

In the present study, dactinomycin (10(-5) M) inhibited the non-adrenergic, non-cholinergic bronchoconstriction upon antidromic vagal nerve stimulation (1 Hz for 1 min) in the isolated perfused guinea-pig lung by 84%. The release of calcitonin gene-related peptide was unchanged, however, suggesting a postjunctional action. Dactinomycin (10(-5), 5 x 10(-5) M) also reduced non-adrenergic non-cholinergic bronchial contractions (maximally by 75%) induced by electrical field stimulation or capsaicin, while the cholinergic component and non-adrenergic non-cholinergic relaxation remained intact. The neurokinin-2 receptor antagonist L-659,877 (10(-6) M) had a similar effect as dactinomycin, inhibiting the non-adrenergic non-cholinergic bronchial contractions by 69%, while the neurokinin-1 receptor antagonist CP-96,345 (10(-6) M) had no effect. The bronchoconstriction evoked by neurokinin A, the selective neurokinin-2 receptor agonist Nle10neurokinin A (4-10) and capsaicin was markedly inhibited by dactinomycin while the contraction induced by substance P (SP), the selective neurokinin-1 receptor agonist Sar9Met(O2)11SP, endothelin-1 and acetylcholine was not affected. In autoradiographic experiments on guinea-pig lung, [125I]neurokinin A-labelled sections showed dense binding in the bronchial smooth muscle layer. Dactinomycin inhibited the specific binding of [125I]neurokinin A in a concentration-dependent manner (IC50 = 6.3 x 10(-6) M) and 66% of [125I]neurokinin A total binding was inhibited by 10(-4) M dactinomycin. In the rat colon, [125I]neurokinin A binding to neurokinin-2 sites on circular smooth muscle was inhibited by dactinomycin with an IC50 value of 7.9 x 10(-6) M. Dactinomycin failed to reduce increased nerve-evoked contractions or those caused by Nle10neurokinin A (4-10) per se in the rat vas deferens, which are considered to be mediated by neurokinin-2 receptor activation. In the rat portal vein, dactinomycin did not influence the contractions caused by the neurokinin-3 selective agonist Pro7neurokinin B. In conclusion, dactinomycin selectively inhibited neurokinin-2 receptor activation in guinea-pig lung and rat colon, but not in rat vas deferens, which may depend on the existence of different neurokinin-2 receptor subtypes. Neurokinin A is most likely the main endogenous excitatory non-adrenergic non-cholinergic transmitter in guinea-pig bronchi.     

Detecting DNA repair capacity of peripheral lymphocytes from cancer patients with UVC challenge test and bleomycin challenge test

The objective of this study was to evaluate DNA repair capacity of cancer patients with the bleomycin (BLM) challenge test and the UVC challenge test. The human peripheral lymphocytes were collected from 33 patients with different kinds of cancers and 33 controls in the same hospital. The lymphocytes of each subject were divided into two groups: (1) In the BLM challenge test, the lymphocytes were treated with BLM (20 microgml(-1)) for 30 min, and repaired for 15 min. The DNA damage before and after BLM exposure was detected with comet assay to assess DNA repair capacity. (2) In the UVC challenge test, the lymphocytes were exposed to UVC (254 nm) at the dose of 1.5 Jm(-2). DNA damage of lymphocytes was measured before UVC exposure and at 90 and 240 min after UVC exposure using comet assay, then DNA repair percentage (DRP) was calculated. The results of this study indicate that the average DRPs of cancer patients were 75.63 +/- 3.11 and 68.98 +/- 4.19% calculated with tail length (TL) and tail moment (TM), respectively, in the BLM challenge test, which were significantly lower than those (91.11 +/- 1.09 and 88.19 +/- 1.71%) of controls (P < 0.01). Also, the mean DRPs of cancer patients were 49.19 +/- 3.47 and 58.27 +/- 3.64% calculated with TL and TM, respectively, in the UVC test, which were significantly lower than those (77.52 +/- 2.06 and 83.12 +/- 2.36%) of controls (P < 0.01). The correlation between the DRPs (%) drawn with TL and TM in the BLM test or between the DRPs (%) drawn with mean TL and mean TM in the UVC challenge test were significant (P < 0.05). The DNA repair capacity measured with the BLM and UVC challenge tests in 33 cancer patients was significantly lower than that in controls.     

Roberts铜盐法测定蔗汁葡聚糖含量的热效应——淀粉对受热蔗汁葡聚糖测定的影响

作者从研究中发现:用Roberts铜盐法测定蔗汁样本葡聚糖含量时,所得结果与蔗汁的受热有关,受热蔗汁的测定值高于真实值,作者将这种现象暂称为Roberts铜盐法测定蔗汁样本葡聚糖含量的热效应。研究表明:蔗汁中的淀粉是引起热效应的重要因素。本文最后提出了一种由淀粉引起的热效应的可行校正方法。     

构建基于移动互联网的患者赋能型心衰健康管理平台

目的构建基于移动互联网的患者赋能型心衰健康管理平台,促进心衰患者进行自我管理,改善临床结局。方法开展课题研究型品管圈活动,搜集高质量临床证据,构建患者赋能型心衰健康管理平台,通过平台推广与应用,对心衰患者行为进行干预。结果平台应用后,医护人员心衰知识水平显著提升,心衰患者自我护理能力明显提升,患者再入院率、死亡率明显下降,应用效果良好。结论基于移动互联网的患者赋能型心衰健康管理平台是心衰慢性病管理的有效手段。     

The Protective Roles of Exercise and Maintenance of Daily Living Routines for Chinese Adolescents During the COVID-19 Quarantine Period

PurposeAdolescents are particularly vulnerable during the COVID-19 quarantine periods and may be at risk for developing psychological distress symptoms that extend beyond a crisis, including depression. This study examined adolescents’ postquarantine depressive symptoms associated with pandemic stressors. The primary aim was to identify potential protective factors that may buffer the association between the presence of COVID-19 cases in adolescents’ communities and their postquarantine depressive symptoms.MethodsAdolescents from public schools were recruited from Zhengzhou city, Henan, China (N = 1,487, M_age=13.14 years, 50% girls). Adolescents reported the presence of confirmed or suspected COVID-19 cases in their communities, their daily activities and routines during the 2-month quarantine period, and depressive symptoms after the quarantine period.ResultsThe presence of cases in adolescents’ communities during the quarantine contributed to more depressive symptoms in adolescents after the quarantine. This association was buffered by adolescents’ spending more time on physical activities and better maintenance of daily living routines during the quarantine period. The presence of community infection was also more strongly associated with depressive symptoms in older adolescents.ConclusionsThe presence of COVID-19 cases in communities contributed to adolescents’ poorer mental health, and the association was stronger for older adolescents. Spending time on physical activities and maintaining daily living routines during the quarantine appear to be practical strategies that can be used by adolescents to mitigate the association between pandemic stressors and their diminishing mental health.     

实验性顺铂诱导急性肾功能衰竭动物模型的研究

1目的　建立顺铂 (cisplatin,CP)诱导的急性肾功能衰竭 (acute renal failure,ARF )大鼠模型 ,探讨 ARF的发病机制。2方法　 SD大鼠静脉一次性注射 CP 6 mg/ kg,动态观察大鼠血清肌酐 (Scr)、尿素氮 (BUN)变化以及肾组织形态学改变。 3结果　对照组不同时间 Scr、BUN差异不明显 (P>0 .0 5 ) ,肾组织形态学正常。模型组 Scr、BUN第 4d较第 1d明显升高 (P<0 .0 5 )。肾组织形态学显示 ,肾脏髓质外侧带大部分肾小管坏死 ,细胞核固缩、溶解、消失 ,管腔扩张 ,有坏死脱落碎屑。 4结论　 CP诱导的大鼠 ARF模型为一较为理想的 ARF模型     

肝硬化患者幽门螺杆菌感染的差异性

观察肝硬变患者幽门螺杆菌感染的差异性及其对病情的影响.结果发现随着肝功能的减退,ChildA组,ChildB组,ChildC组HP的感染率逐步升高,CagA、VacA阳性率也逐步升高,ChildC与各组比较HP的感染率,CagA、VacA的阳性率均显著增高,差异有显著性(P<0.05),胃排空无差异(P>0.05).其余各组间比较无差异(P>0.05).提示肝硬变患者与对照组比较HP的感染率及其菌株无显著差异,胃的排空与HP的感染无关,肝脏功能状况与HP感染相关性有待进一步研究.