地衣芽孢杆菌对儿童诺如病毒性肠炎患者血清PCT、IL6、IL8水平的影响

目的探讨地衣芽孢杆菌对诺如病毒性肠炎患儿血清前降钙素(PCT)、白介素-6(IL-6)和白介素-8(IL-8)水平的影响。方法将86例诺如病毒性肠炎患儿随机分为观察组和对照组,各43例。两组患儿均予以蒙脱石散等对症治疗,观察组患儿加用地衣芽孢杆菌活菌胶囊,1粒/次,3次/d,连续治疗7 d。采用免疫荧光法测定患儿血清PCT水平,采用ELISA法测定患儿IL-6和IL-8的水平,观察两组患儿治疗前后PCT、IL-6和IL-8水平的变化。结果治疗后,观察组患儿血清PCT、IL-6和IL-8水平分别为(4.1±1.8)μg/L、(26.5±5.4)ng/L和(33.5±4.9)ng/L,对照组患儿血清PCT、IL-6和IL-8水平分别为(7.2±2.3)μg/L、(51.2±8.3)ng/L和(58.4±9.0)ng/L,与治疗前相比均显著降低,且观察组各指标水平显著优于对照组(t=6.960、16.357、15.934,均P0.001)。结论地衣芽孢杆菌活菌胶囊辅助治疗能显著降低诺如病毒性肠炎患儿血清PCT、IL-6和IL-8水平,抑制炎症反应,值得推广使用。     

老年脓毒血症患者血清中白细胞介素及外周血淋巴细胞亚群变化的临床意义

目的分析不同预后老年脓毒血症患者血清中白细胞介素(IL)-18、IL-35及外周血淋巴细胞亚群的差异,分析其变化的临床意义。方法选取第三军医大学西南医院重症医学科2012年4月至2015年4月收治的157例老年脓毒血症患者,纳入实验组,并选取同期150例健康体检者,纳入正常对照组,比较两组受试者血清IL-18、IL-35及外周血淋巴细胞亚群水平。按照患者病变进展情况,分别于其病情进展至脓毒血症期、严重脓毒血症期、脓毒血症休克期时采血,再次检查其血清IL-18、IL-35水平,并按照患者预后分为存活组、死亡组,比较各组患者血清IL-18、IL-35及外周血淋巴细胞亚群水平。采用单因素方差分析,组间两两比较采用LSD-t检验。结果实验组IL-18、CD_8~+水平分别为(103.89±19.57)μg/L、(23.87±6.02)﹪,显著高于对照组(t_1=9.376,t_2=3.509,P均0.01),其IL-35、CD_4~+、CD_4~+/CD_8~+水平分别为(157.59±46.42)μg/L、(26.27±4.86)﹪、(1.23±0.15),显著低于对照组(t_1=10.442,t_2=5.347,t_3=3.226,P均0.05);随着患者病变程度进展,其IL-18、CD_8~+水平显著升高,IL-35、CD_4~+、CD_4~+/CD_8~+水平显著下降;存活组患者IL-18、CD_8~+水平分别为(87.81±20.36)μg/L、(22.09±5.41)﹪,显著低于死亡组(t_1=9.950,t_2=3.998,P均0.05),其IL-35、CD_4~+、CD_4~+/CD_8~+水平分别为(170.58±34.71)μg/L、(27.31±6.25)﹪、(1.24±0.27),显著高于死亡组,差异有统计学意义(t_1=8.423,t_2=4.512,t_3=5.368,P均0.05)。结论老年脓毒血症患者IL-18、CD_8~+表达水平上升,IL-35、CD_4~+、CD_4~+/CD_8~+表达水平下降,随其病情加重与预后变差,上述指标变化更为明显,联合检测血清IL-18、IL-35及外周血淋巴细胞亚群水平有望早期指导预后判断。     

溃疡性结肠炎患者外周血C 反应性蛋白、血清降钙素原及白细胞介素-6 水平及临床意义

目的:分析溃疡性结肠炎(Ulcerative colitis,UC)患者血清降钙素原(Procalcitonin,PCT)、C反应蛋白(C-reactive protein,CRP)及白细胞介素-6(Interleukin-6,IL-6)水平与病情严重程度的关系。方法:选择2013年5月-2015年5月在我院就诊的溃疡性结肠炎患者91例作为研究对象,另选择同期在我院接受健康体检的志愿者69例作为对照组。检测并比较两组研究对象血清降钙素原(PCT)、C反应性蛋白(CRP)及白细胞介素-6(IL-6)的水平,并分析PCT,CRP及IL-6水平与溃疡性结肠炎的相关性。结果:溃疡性结肠炎患者PCT水平为(1.24±0.23)ng/m L,对照组PCT水平为(0.12±0.10)ng/m L,溃疡性结肠炎患者PCT水平显著高于对照组,差异具有统计学意义(P0.05);溃疡性结肠炎患者CRP水平为(105.27±19.93)mg/m L,对照组CRP水平为(7.62±2.97)mg/m L,溃疡性结肠炎患者血清CRP水平显著高于对照组,差异具有统计学意义(P0.05);溃疡性结肠炎患者IL-6水平为(248.15±35.60)ng/m L,对照组IL-6水平为(144.05±20.26)ng/m L,溃疡性结肠炎患者血清IL-6水平显著高于对照组,差异具有统计学意义(P0.05)。溃疡性结肠炎患者血清PCT,IL-6及CRP水平之间均呈正相关关系(r=0.301,0.468,0.413,P0.01)。结论:溃疡性结肠炎患者血清PCT,CRP及IL-6水平均显著高于健康人群,其水平变化与患者病情严重程度有关。因此,我们在临床实践中应予以重视。     

血清CRP, PCT 水平在脓毒血症患者中的早期诊断及预后评估价值

目的:探讨血清C反应蛋白(CRP)、降钙素原(PCT)水平在脓毒血症患者中的早期诊断及预后评估价值。方法:100例重症患者按照是否发生全身感染分为脓毒血症组67例、非脓毒血症组33例;脓毒血症组按照预后分为存活组42例、死亡组25例,同时选取健康者30例为正常对照组,进入重症监护室24小时后,抽取患者静脉血8ml,CRP采用免疫比浊法,PCT采用免疫层析法检测,分析CRP、PCT水平在脓毒血症患者早期诊断及预后价值。结果:CRP、PCT水平在组间差异具有统计学意义(P0.05),其中脓毒血症组和非脓毒血症组水平均高于对照组,脓毒血症组水平高于非脓毒血症组,差异具有统计学意义(P0.05);脓毒血症存活组患者CRP、PCT随着住院时间延长逐渐降低,差异具有统计学意义(P0.05),死亡组从第3天较第1天升高,第7、9天逐渐降低,但降低幅度不大,差异无统计学意义(P0.05);同一住院时间死亡组CRP、PCT水平均高于存活组,差异具有统计学意义(P0.05)。CRP、PCT联合并联检测对于早期发现脓毒血症具有较高的灵敏度。结论:PCT、CRP联合并联检测对于脓毒血症有更好的早期诊断价值,其表达水平可以较好地反映患者预后。     

脐血IL-6、IL-8、TNF-a在早产儿脑损伤中的临床意义及预测价值

目的研究脐血白介素-6(IL-6)、白介素-8(IL-8)和肿瘤坏死因子-a(TNF-a)在34周前早产儿脑损伤中的临床意义及预测价值。方法对59例34周前出生早产儿用酶联免疫吸附试验检测脐血IL-6、IL-8、TNF-a;将母亲的胎盘胎膜组织行病理学检查,诊断有无绒毛膜羊膜炎;早产儿出生后72 h内头颅超声检查,诊断有无脑损伤。结果 (1)早产儿脑损伤组脐血IL-6[(7.69±1.69)μg/L]、IL-8[(3.87±0.26)μg/L]及TNF-a[(3.67±1.12)μg/L]明显高于无脑损伤组[分别为(5.78±0.59)μg/L、(1.79±0.66)μg/L、(1.91±0.37)μg/L],2组比较差异有统计学意义(P<0.05);母亲患绒毛膜羊膜炎组脐血IL-6[(6.98±0.17)μg/L]、IL-8[(3.27±0.27)μg/L]和TNF-a[(3.24±1.37)μg/L]明显高于无绒毛膜羊膜炎组[分别为(6.13±0.15)μg/L、(2.04±0.79)μg/L、(2.07±0.54)μg/L],2组比较差异有统计学意义(P<0.05);(2)应用ROC工作曲线进行分析,脐血IL-6≥6.46μg/L、IL-8≥2.0μg/L、TNF-a≥2.42μg/L作为诊断早产儿脑损伤标准时,其灵敏度分别为95.5%、95.5%和100%;特异度分别为94.6%、70.3%和97.3%;(3)母亲有绒毛膜羊膜炎时,早产儿脑损伤发生率明显升高。结论脐血IL-6、IL-8和TNF-a不仅反映母亲的感染情况和早产儿脑损伤,并且对早产儿脑损伤具有一定的预测价值。     

脓毒症患儿血浆miR-146a、miR-223表达与IL-6、IL-10、TNF-α 水平变化的临床意义分析

目的:探讨脓毒症患儿血浆微RNA-146a(miR-146a)、miR-223表达及与白细胞介素-6(IL-6)、IL-10和肿瘤坏死因子(TNF-α)的关系。方法:选取2016年2月至2017年2月在我院治疗的脓毒症患儿44例作为脓毒症组,同时选取32例全身性炎症反应综合征(SIRS)患儿(SIRS组)和40例健康儿童(对照组),检测和比较各组患儿血浆miR-146a、miR-223、IL-6、IL-10和TNF-α的表达,同时采用序贯器官衰竭估计评分(SOFA评分)评价脓毒症患儿的病情。结果:脓毒症组miR-146a、miR-223、IL-6和IL-10表达分别为(5.90±1.22)×10~(-5)、(13.17±2.13)×10~(-4),20.21(12.06,64.13)ng/L和17.60(8.94,70.11)pg/m L,明显高于SIRS组和对照组(P0.05);脓毒症组和SIRS组血浆TNF-水平分别为(22.50(22.50,29.80)pg/m L和(23.40(19.41,30.01)pg/m L,明显高于对照组(P0.05);患儿miR-146a、miR-223与SOFA评分呈正相关(rs=0.411和0.321,P0.05),而血浆IL-6、IL-10及TNF-α水平与SOFA评分无显著相关性(P0.05);miR-146a与血浆IL-6、IL-10水平呈显著正相关(rs=0.297和0.301,P0.05),miR-223与血浆TNF-α水平呈正相关(rs=0.284,P0.05)。结论:脓毒症患儿血浆miR-146a和miR-223表达、IL-6、IL-10和TNF-α水平均异常上调,且血浆miR-146a和miR-223表达与IL-6、IL-10、TNF-水平及病情程度显著相关。     

PCT和CRP在感染性疾病诊断中的临床意义

目的:探讨PCT、CRP在感染性疾病诊断中的价值,评价两者与感染类型的相关性。方法:回顾性统计分析420例发热待查的患者血清PCT,血浆CRP浓度与感染的关系,采用胶体金法检测血清中PCT的浓度,免疫荧光比色法检测血浆中CRP浓度,血培养及血清学的方法检测感染是否存在及感染类型。结果:通过血培养或血清学鉴定出132例存在细菌感染(细菌组),病毒感染103例(病毒组),细菌病毒混合感染76例(混合感染组),109例阴性(非感染组)。PCT在细菌组水平最高(20.6±6.7)μg/L,非感染组水平最低(8.7±2.3)μg/L,四组间差异有统计学意义(F=34.69,P0.05)。CRP在混合组中水平最高(18.1±3.7)mg/L,在非感染组水平最低(5.8±1.7)mg/L,四组间差异有统计学意义(F=23.55,P0.05)。PCT对细菌感染检测的敏感度为92.7%,特异度为63.2%。PCT对病毒感染检测的敏感度为78.7%,特异性为46.0%。细菌感染组、病毒感染组和混合感染组血清CRP和PCT均呈正相关(P=0.000.05)。结论:细菌感染的PCT、CRP血清浓度明显高于病毒感染,两者对细菌感染患者的特异性均明显高于病毒感染,细菌感染PCT血清浓度较CRP变化敏感。     

内毒素、PCT联合NLR对经皮肾镜碎石术后患者尿源性脓毒血症的预测价值

摘要 目的：探讨内毒素、降钙素原（PCT）联合中性粒细胞与淋巴细胞比值（NLR）对经皮肾镜碎石术（PCNL）术后患者发生尿源性脓毒血症的预测价值。方法：选取2020年5月-2023年5月于西安医学院第二附属医院和空军军医大学第一附属医院泌尿外科行PCNL的患者750例作为研究对象。根据尿源性脓毒症发生情况分为尿源性脓毒血症组（n=45）和非脓毒血症组（n=705）。检测PCNL术前血清内毒素、PCT、中性粒细胞与淋巴细胞水平，并计算NLR。对比两组血清内毒素、PCT水平及NLR。采用多因素Logistic回归模型分析PCNL术后患者发生尿源性脓毒血症的影响因素。绘制受试者工作特征（ROC）曲线分析血清内毒素、PCT联合NLR预测PCNL术后患者发生尿源性脓毒血症的临床效能。结果：与非脓毒血症组相比，尿源性脓毒血症组血清内毒素、PCT及NLR更高（P<0.05）。多因素Logistic回归模型分析结果显示，血清内毒素升高、PCT升高、NLR升高、尿白细胞阳性、术前发热及鹿角型结石是PCNL术后患者发生尿源性脓毒血症的独立危险因素（P<0.05）；ROC曲线分析结果显示，血清内毒素、PCT联合NLR检测预测PCNL术后患者发生尿源性脓毒血症的曲线下面积（AUC）为0.913，高于上述各指标单独检测。结论：PCNL术前血清内毒素、PCT和NLR升高可能与术后患者发生尿源性脓毒血症有关。血清内毒素、PCT水平升高、NLR升高、术前发热、尿白细胞阳性、鹿角型结石是PCNL术后患者发生尿源性脓毒血症的危险因素。血清内毒素、PCT联合NLR检测对PCNL术后患者发生尿源性脓毒血症具有较高预测价值。     

高原寒环境暴露对急进入高原健康人群肾功能的影响

目的:探讨高原低压低氧寒环境对急进高原的平原健康人群肾功能的影响。方法:选取30例长期居住兰州地区急进高原(海拔3300米、日平均气温-4度)健康人群,对比分析所有受试者进驻高原前和进驻高原后第24 h、72 h、7天、14天、28天尿IL-18(白介素-18)、尿NAGL(中性粒细胞明胶酶相关性脂质运载蛋白)、尿KIM-1(肾损伤因子-1)及血肌酐水平的变化。结果:共28人完成全部6次尿液及血标本采集并检测,其中2名女性因某次采集点处于月经期剔除,其中男性17人、女性11人,平均年龄26.8±3.2岁(男性28.3±4.2岁,女性24.8±2.6岁)。进入高原前和进驻高原后第24 h、72 h、7天、14天、28天尿IL-18检测值分别为3.62±0.32 ng/L、11.20±0.65 ng/L(P<0.001,较进入前组比较)、6.32±0.46 ng/L(P<0.001)、4.36±0.68 ng/L(P<0.05)、3.58±0.71 ng/L、3.32±0.46 ng/L;尿NAGL水平分别为0.126±0.20μg/L、0.513±0.003μg/L(P<0.001)、0.116±0.006μg/L、0.009±0.001μg/L、0.121±0.010μg/L、0.632±0.009μg/L;尿KIM-1水平分别为2.61±0.22 ng/L、18.20±0.69 ng/L(P<0.001)、6.32±0.46 ng/L(P<0.001)、6.36±0.68 ng/L(P<0.001)、2.58±0.31 ng/L、2.32±0.26 ng/L;血肌酐水平分别为61.0±9.16μmol/L、58.5±8.13μmol/L、80.3±10.38μmol/L(P<0.05)、76.5±12.04μmol/L(P<0.05)、62.6±10.14μmol/l、62.3±8.18μmol/L。结论:急进高原健康入群早期肾功能有改变,其中尿IL-18、尿KIM-1、尿NAGL水平较血肌酐水平变化更早、更敏感。     

脑血疏口服液联合依达拉奉对高血压脑出血的治疗效果及对血清IL-6，IL-1β，MMP-9的影响

目的:研究脑血疏口服液联合依达拉奉对高血压脑出血的治疗效果及对血清白介素-6(IL-6)、IL-1β、基质金属蛋白酶-9(MMP-9)的影响。方法:选取2014年10月至2016年9月我院收治的102例高血压脑出血患者,根据入院顺序分为观察组和对照组,51例每组。对照组使用常规治疗,观察组在此基础上采取脑血疏口服液联合依达拉奉完成治疗。比较两组患者临床疗效,神经功能评分、血肿周围水肿量、血肿量,血清IL-6、IL-1β、MMP-9水平。结果:治疗后,观察组临床总有效率显著高于对照组[94.12%(48/51)比78.43%(40/51)](P0.05);神经功能评分、血肿量、周围水肿量显著低于对照组[(11.04±1.21)分、(8.65±0.54)m L、(5.87±0.54)m L比(19.87±1.76)分、(13.56±1.23)m L、(9.65±0.92)m L](P0.05);血清IL-6、IL-1β、MMP-9水平低于对照组[(8.98±0.87)ng/m L、(12.34±1.21)ng/L、(74.21±8.42)ng/L比(11.21±1.02)ng/m L、(23.87±2.37)ng/L、(92.17±9.86)ng/L](P0.05)。两组患者不良反应的发生率比较差异无统计学意义(P0.05)。结论:脑血疏口服液联合依达拉奉治疗高血压脑出血的临床疗效明显优于常规治疗,可能与其有效降低患者血清IL-6、IL-1β、MMP-9水平有关。     

Degradation and conversion of somatostatin in normal and diabetic rats in vivo and in vitro

Plasma somatostatin-like immunoreactivity in the portal and jugular veins of streptozotocin diabetic rats was compared with that in normal control rats. In the diabetic group, somatostatin levels in the portal (p less than 0.05) and jugular (p less than 0.01) veins were both elevated compared with those in the control group. Moreover, the degree of elevation was greater in the jugular vein than in the portal vein. To further investigate the role of the liver in the clearance of somatostatin-28 in vivo, 2 micrograms of somatostatin-28 was administered as a bolus into the external jugular vein of intact and functionally hepatectomized rats. The mean half-time of somatostatin-28 was significantly longer in intact diabetic rats than in controls (p less than 0.05). The functional hepatectomy did not cause a significant difference in the half-time in diabetic rats but made it longer in control rats. These results suggest that the longer half-time of somatostatin-28 in diabetic rats in vivo is due to its slower hepatic clearance. The hepatic clearance of somatostatin-28 and somatostatin-14 was further studied in vitro using a recirculating liver perfusion method. The hepatic clearance of 1.2 nM of either somatostatin-28 or somatostatin-14 was significantly lower in diabetic rats than in controls (p less than 0.01). This indicates that elevated plasma somatostatin levels in diabetic rats are caused at least in part by decreased hepatic clearance of somatostatin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Production of arsine and methylarsines in soil and in culture

Arsenate, arsenite, monomethylarsonate, and dimethylarsinate were added to different soils, and evolution of gaseous arsenical products was determined over 3 weeks. Arsine was produced in all three soils from all substrates, whereas methylarsine and dimethylarsine were produced only from methylarsonate and dimethylarsinate, respectively. At least three times more arsine than dimethylarsine was produced in soil incubated with dimethylarsinate. Resting cell suspensions of Pseudomonas and Alcaligenes produced arsine as the sole product when incubated anaerobically in the presence of arsenate or arsenite. In all instances, no trimethylarsine was observed, nor could any evidence be shown for the methylation of any arsenical substrate in soil or in culture. It was concluded that reduction to arsine, not methylation to trimethylarsine, was the primary mechanism for gaseous loss of arsenicals from soil.     

Growth and mitogenic effects of arylphorin in vivo and in vitro

In insects, developmental responses are organ- and tissue-specific. In previous studies of insect midgut cells in primary tissue cultures, growth-promoting and differentiation factors were identified from the growth media, hemolymph, and fat body. Recently, it was determined that the mitogenic effect of a Manduca sexta fat body extract on midgut stem cells of Heliothis virescens was due to the presence of monomeric alpha-arylphorin. Here we report that in primary midgut cell cultures, this same arylphorin stimulates stem cell proliferation in the lepidopterans M. sexta and Spodoptera littoralis, and in the beetle Leptinotarsa decemlineata. Studies using S. littoralis cells confirm that the mitogenic effect is due to free alpha-arylphorin subunits. In addition, feeding artificial diets containing arylphorin increased the growth rates of several insect species. When tested against continuous cell lines, including some with midgut and fat body origins, arylphorin had no effect; however, a cell line derived from Lymantria dispar fat body grew more rapidly in medium containing a chymotryptic digest of arylphorin.     

Antiplatelet and antithrombotic activities of purpurogallin in vitro and in vivo

Enzymatic oxidation of pyrogallol was efficiently transformed to an oxidative product, purpurogallin (PPG). Here, the anticoagulant activities of PPG were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin and activated factor X (FXa). And, the effects of PPG on expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated in tumor necrosis factor (TNF)-α activated human umbilical vein endothelial cells (HUVECs). Treatment with PPG resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, as well as inhibited production of thrombin and FXa in HUVECs. In addition, PPG inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. PPG also elicited anticoagulant effects in mice. In addition, treatment with PPG resulted in significant reduction of the PAI-1 to t-PA ratio. Collectively, PPG possesses antithrombotic activities and offers a basis for development of a novel anticoagulant. [BMB Reports 2014; 47(7): 376-381]     

Growth and reproduction of Arabidopsis thaliana in relation to storage of starch and nitrate in the wild-type and in starch-deficient and nitrate-uptake-deficient mutants

We have investigated the interactions between resource assimilation and storage in rosette leaves, and their impact on the growth and reproduction of the annual species Arabidopsis thaliana. The resource balance was experimentally perturbed by changing (i) the external nutrition, by varying the nitrogen supply; (ii) the assimilation and reallocation of resources from rosette leaves to reproductive organs, by cutting or covering rosette leaves at the time of early flower bud formation, and (iii) the internal carbon and nitrogen balance of the plants, by using isogenic mutants either lacking starch formation (PGM mutant) or with reduced nitrate uptake (NU mutant). When plants were grown on high nitrogen, they had higher concentrations of carbohydrates and nitrate in their leaves during the rosette phase than during flowering. However, these storage pools did not significantly contribute to the bulk flow of resources to seeds. The pool size of stored resources in rosette leaves at the onset of seed filling was very low compared to the total amount of carbon and nitrogen needed for seed formation. Instead, the rosette leaves had an important function in the continued assimilation of resources during seed ripening, as shown by the low seed yield of plants whose leaves were covered or cut off. When a key resource became limiting, such as nitrogen in the NU mutants and in plants grown on a low nitrogen supply, stored resources in the rosette leaves (e.g. nitrogen) were remobilized, and made a larger contribution to seed biomass. A change in nutrition resulted in a complete reversal of the plant response: plants shifted from high to low nutrition exhibited a seed yield similar to that of plants grown continuously on a low nitrogen supply, and vice versa. This demonstrates that resource assimilation during the reproductive phase determines seed production. The PGM mutant had a reduced growth rate and a smaller biomass during the rosette phase as a result of changes in respiration caused by a high turnover of soluble sugars ( Caspar et al. 1986 ; W. Schulze et al. 1991 ). During flowering, however, the vegetative growth rate in the PGM mutant increased, and exceeded that of the wild-type. By the end of the flowering stage, the biomass of the PGM mutant did not differ from that of the wild-type. However, in contrast to the wild-type, the PGM mutant maintained a high vegetative growth rate during seed formation, but had a low rate of seed production. These differences in allocation in the PGM mutant result in a significantly lower seed yield in the starchless mutants. This indicates that starch formation is not only an important factor during growth in the rosette phase, but is also important for whole plant allocation during seed formation. The NU mutant resembled the wild-type grown on a low nitrogen supply, except that it unexpectedly showed symptoms of carbohydrate shortage as well as nitrogen deficiency. In all genotypes and treatments, there was a striking correlation between the concentrations of nitrate and organic nitrogen and shoot growth on the one hand, and sucrose concentration and root growth on the other. In addition, nitrate reductase activity (NRA) was correlated with the total carbohydrate concentration: low carbohydrate levels in starchless mutants led to low NRA even at high nitrate supply. Thus the concentrations of stored carbohydrates and nitrate are directly or indirectly involved in regulating allocation.     

Importance of guanine nitration and hydroxylation in DNA in vitro and in vivo

Guanine (Gua) modification by nitrating and hydroxylating systems was investigated in DNA. In isolated calf thymus DNA, 8-NO(2)-Gua and 8-oxo-Gua were dose-dependently formed with peroxynitrite, and 8-NO(2)-Gua was released in substantial amounts. Myeloperoxidase (MPO) with H(2)O(2) and NO(2)(-) reacted with calf thymus DNA to form 8-NO(2)-Gua dose dependently without release of 8-NO(2)-Gua. The frequency of strand breaks was higher than the sum of 8-NO(2)-Gua and 8-oxo-Gua, particularly in the MPO-treated DNA, indicating the importance of other types of damage. The activation of human neutrophils and lymphocytes with phorbol ester did not induce 8-NO(2)-Gua and 8-oxo-Gua in their nuclear DNA. However, 8-NO(2)-Gua was found in calf thymus DNA co-incubated with activated neutrophils in the presence of NO(2)(-). No significant formation of 8-NO(2)-Gua was found in liver DNA from mice treated with Escherichia coli lipopolysaccharide. The incubation of peroxynitrite or MPO-H(2)O(2)-NO(2)(-)-treated DNA with formamidopyrimidine glycosylase (Fpg) released 8-oxo-Gua, but not 8-NO(2)-Gua, indicating that 8-NO(2)-Gua is not a substrate for Fpg. Although 8-NO(2)-Gua was generated in isolated DNA by different nitrating systems, other types of damage were formed in abundance, and the lesion could not be found reliably in nuclear DNA, suggesting that the biological importance is limited.