Nonrandom,diversifying processes are disproportionately strong in the smallest size classes of a tropical forest

A variety of ecological processes influence diversity and species composition in natural communities. Most of these processes, whether abiotic or biotic, differentially filter individuals from birth to death, thereby altering species’ relative abundances. Nonrandom outcomes could accrue throughout ontogeny, or the processes that generate them could be particularly influential at certain stages. One long-standing paradigm in tropical forest ecology holds that patterns of relative abundance among mature trees are largely set by processes operating at the earliest life cycle stages. Several studies confirm filtering processes at some stages, but the longevity of large trees makes a rigorous comparison across size classes impossible without long-term demographic data. Here, we use one of the world’s longest-running, plot-based forest dynamics projects to compare nonrandom outcomes across stage classes. We considered a cohort of 7,977 individuals in 186 species that were alive in 1971 and monitored in 13 mortality censuses over 42 y to 2013. Nonrandom mortality with respect to species identity occurred more often in the smaller rather than the larger size classes. Furthermore, observed nonrandom mortality in the smaller size classes had a diversifying influence; species richness of the survivors was up to 30% greater than expected in the two smallest size classes, but not greater than expected in the larger size classes. These results highlight the importance of early life cycle stages in tropical forest community dynamics. More generally, they add to an accumulating body of evidence for the importance of early-stage nonrandom outcomes to community structure in marine and terrestrial environments.Processes that operate nonrandomly with respect to species identity contribute to the structure of natural communities (1–3). Evidence from diverse rain forests includes demographic transitions from seeds to seedlings (4, 5), at the seedling (6, 7) and sapling stages (8) and among large trees (9–12). Although the relative contributions of nonrandom processes at each life cycle stage to determining patterns of abundance and diversity in the mature canopy are unknown, one long-standing paradigm is that community assembly is mediated primarily by events occurring from seed dispersal through seedling germination and small-sapling establishment (13–17). However, despite suggestive patterns (6, 7, 18, 19), evidence is lacking for the comparative strength of early-stage dynamics in determining canopy abundance and diversity.Numerous studies demonstrate significant interspecific variation in the susceptibility of tropical tree seedlings to postgermination hazards, including natural enemies (20, 21), adverse climatic or edaphic conditions (22), physical damage (23), and the crowding or shared-enemies effects of con- and heterospecific neighbors (24, 25). In other words, the per capita probability of seedling mortality is nonrandom because the probability of death is not the same for all individuals in a local community – it is dependent to some degree on species identity. In plant communities in which generation times are relatively short, experiments have demonstrated that nonrandom mortality through these early transitions can be sufficiently strong to affect the species composition of mature plants (26–29). Such demonstrations are impossible in studies of a few decades or less in duration when generation times are long and even juveniles live for several decades or centuries, such as in many tropical forests. Even so, some hypotheses explicitly identify stressors that affect plants at the earliest life cycle stages (such as pests and pathogens, 13, 14, 30) as disproportionately influential. In addition, some empirical studies find a lack of support for nonrandom processes operating among larger stems (31, 32). Together these hypotheses and observations provide the rationale underpinning the considerable body of research on seed and seedling dynamics in tropical forests worldwide. However, no empirical or experimental assessment has been made of the relative contributions across life cycle stages from nonrandom mortality.Here, we evaluate the comparative contribution of early-stage dynamics using a multidecadal study of a tropical forest dynamics plot initiated by one of us (J.H.C.) in 1963 at a site in north Queensland, Australia. We considered a cohort of 7,977 individuals in 186 species that were alive on the plot in 1971, from tiny seedlings to large canopy trees, whose fates were monitored in 13 mortality censuses over 42 y to 2013. Individuals were assigned to one of six size classes (

Effects of metoprolol,methyldopa, and nifedipine on endothelial progenitor cells in patients with gestational hypertension and preeclampsia

Endothelial progenitor cells (EPCs) are critical for vascular regeneration and function, but are reduced in hypertensive disorders of pregnancy. We aimed to determine the possible effects of antihypertensive drugs, such as metoprolol, methyldopa, and nifedipine, on EPC number and functions in patients with gestational hypertension and preeclampsia. We collected blood samples from 30 normal pregnant women, 67 patients with gestational hypertension and 48 patients with preeclampsia. The patients received no drug or an antihypertensive drug, such as metoprolol, methyldopa, or nifedipine, between 20 and 24 weeks of gestation. The number of EPCs and circulating endothelial cells (CECs) in the blood was measured by flow cytometry. Moreover, colony formation and migration assays were performed on the isolated EPCs. Both the systolic and diastolic blood pressure (BP) increased, while the percentage of flow‐mediated vasodilatation (FMD) decreased in patients with gestational hypertension and preeclampsia, compared to the healthy controls at 20 weeks of gestation. CEC number increased in the patients, whereas EPC counts decreased. Furthermore, EPC colony formation and migration abilities were also impaired in the patients. However, administration of metoprolol, methyldopa, or nifedipine effectively restored the systolic and diastolic BP, FMD%, EPCs, and CEC numbers, as well as EPC migration capacity. Endothelial progenitor cells colony formation ability selectively improved with methyldopa and nifedipine. In patients receiving no drugs, most of these indexes worsened within 4 weeks (study duration). This study revealed a new pharmacological action of these antihypertensive drugs against gestational hypertension and preeclampsia, thus supporting their clinical use.     

Immunohistochemistry of γ‐H2AX as a method of early detection of urinary bladder carcinogenicity in mice

Phosphorylated histone H2AX (γ‐H2AX) has been demonstrated as a DNA damage marker both in vitro and in vivo. We previously reported the effects of genotoxic carcinogens in the urinary bladder of rats by immunohistochemical analysis of γ‐H2AX using samples from 28‐day repeated‐dose tests. To evaluate the application of γ‐H2AX as a biomarker of carcinogenicity in the bladder, we examined species differences in γ‐H2AX formation in the urinary bladder of mice. Six‐week‐old male B6C3F₁ mice were treated orally with 12 chemicals for 4 weeks. Immunohistochemical analysis demonstrated that N‐butyl‐N‐(4‐hydroxybutyl)nitrosamine, p‐cresidine and 2‐acetylaminofluorene (2‐AAF), classified as genotoxic bladder carcinogens, induced significant increases in γ‐H2AX levels in the bladder urothelium. In contrast, genotoxic (2‐nitroanisole, glycidol, N‐nitrosodiethylamine and acrylamide) and non‐genotoxic (dimethylarsinic acid and melamine) non‐bladder carcinogens did not upregulate γ‐H2AX. Importantly, 2‐nitroanisole, a potent genotoxic bladder carcinogen in rats, significantly increased the proportion of γ‐H2AX‐positive cells in rats only, reflecting differences in carcinogenicity in the urinary bladder between rats and mice. Significant upregulation of γ‐H2AX was also induced by uracil, a non‐genotoxic bladder carcinogen that may be associated with cell proliferation, as demonstrated by increased Ki67 expression. 2‐AAF caused γ‐H2AX formation mainly in the superficial layer, together with reduced and disorganized expression of uroplakin III, unlike in rats, suggesting the mouse‐specific cytotoxicity of 2‐AAF in umbrella cells. These results suggest γ‐H2AX is a useful biomarker reflecting species differences in carcinogenicity in the urinary bladder.     

酚妥拉明联合亚胺培南西司他丁治疗重症新生儿肺炎的疗效分析

目的 研究酚妥拉明联合亚胺培南西司他丁治疗重症新生儿肺炎的疗效。方法 选择2015年1月-2017年12月驻马店市中心医院收治的108例重症新生儿肺炎患者,随机分为两组。对照组单独采用亚胺培南西司他丁治疗,每次0.5 g,每6 h给药1次;观察组在对照组基础上联合给予酚妥拉明0.2 mg/kg,每天给药2次。两组均治疗5 d。比较两组的症状改善情况、血清炎症因子和肺功能的改变情况。结果 与对照组有效率74.07%比较,观察组有效率88.89%明显提高,差异有统计学意义（P<0.05）。观察组的体温恢复正常时间、每天吸痰次数以及肺部啰音消失时间明显低于对照组,差异有统计学意义（P<0.05）。两组治疗后的血清C反应蛋白（CRP）、白介素-4（IL-4）以及白介素-6（IL-6）水平均明显降低,白介素-10（IL-10）水平明显升高,同组治疗前后比较差异均有统计学意义（P<0.05）;且观察组明显优于对照组,组间差异有统计学意义（P<0.05）。两组治疗后的第一秒最大呼气量（FEV1）、用力肺活量（FVC）、用力呼气25%流速（MEF25）、最大呼气流速峰值（PEF）及用力呼气50%流速（MWV50）均明显升高,同组治疗前后比较差异有统计学意义（P<0.05）;且观察组以上指标明显高于对照组,组间差异有统计学意义（P<0.05）。结论 酚妥拉明联合亚胺培南西司他丁治疗重症新生儿肺炎的效果较为确切,值得应用推广。     

甲泼尼龙联合拉氧头孢治疗儿童重症社区获得性肺炎的临床研究

目的探讨注射用甲泼尼龙琥珀酸钠联合注射用拉氧头孢钠治疗儿童重症社区获得性肺炎的临床疗效。方法选取2017年8月—2018年8月西安交通大学第一附属医院收治的重症社区获得性肺炎患儿80例作为研究对象,采用随机对照表法将所有患儿分为对照组和治疗组,每组各40例。对照组患儿静脉滴注注射用拉氧头孢钠,40mg/(kg·d),2次/d,静脉滴注30 min以上。治疗组患者在对照组基础上静脉滴注注射用甲泼尼龙琥珀酸钠30 mg/kg,静脉滴注30 min以上。两组患儿均持续治疗7 d。观察两组患者的临床疗效,同时比较两组治疗前后的临床症状改善时间、动脉血气指标和血清炎性因子水平。结果治疗后,治疗组的总有效率为92.50%,显著高于对照组的82.50%,两组比较差异具有统计学意义(P0.05)。治疗后,治疗组患儿发热缓解时间、憋喘缓解时间、肺部啰音消失时间、咳嗽消失时间均显著短于对照组,两组比较差异具有统计学意义(P0.05)。治疗后,两组动脉血氧饱和度(SaO2)均显著升高,二氧化碳分压(p CO2)显著下降,同组治疗前后比较差异具有统计学意义(P0.05);治疗后,治疗组动脉血气指标明显优于对照组,两组比较差异具有统计学意义(P0.05)。治疗后,两组患儿超敏C反应蛋白(hs-CRP)、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)水平均显著降低,同组治疗前后比较差异具有统计学意义(P0.05);治疗后,治疗组血清炎性因子水平显著低于对照组,两组比较差异具有统计学意义(P0.05)。结论注射用甲泼尼龙琥珀酸钠联合注射用拉氧头孢钠治疗儿童重症社区获得性肺炎具有较好的临床疗效,能够显著改善患儿临床症状和动脉血气指标,降低血清炎性因子水平,具有一定的临床推广应用价值。     

美罗培南持续泵入联合乌司他丁治疗重症肺炎的临床研究

目的探讨注射用美罗培南持续泵入联合注射用乌司他丁治疗重症肺炎的临床疗效。方法选取2015年6月—2018年6月天津市宁河区医院收治的104例重症肺炎患者作为研究对象,采用随机数字表法将所有患者分为静脉滴注美罗培南组(33例)、持续泵入美罗培南组(35例)、联合组(36例)。静脉滴注美罗培南组采用静脉滴注注射用美罗培南,将1 g与0.9%氯化钠注射液250mL混合,1次/8h;持续泵入美罗培南组持续泵入注射用美罗培南,将3g与0.9%氯化钠注射液50mL混合,1次/d;联合组在持续泵入美罗培南组的基础上静脉注射注射用乌司他丁,将25万U加入0.9%氯化钠注射液100 mL混合,2次/d。3组患者均治疗7 d。观察患者的临床疗效,同时比较3组的临床症状消失时间、急性生理与慢性健康状况评估Ⅱ评分(APACHEⅡ)、动脉血气指标和血清炎症因子水平。结果治疗后,静脉滴注美罗培南组、持续泵入美罗培南组和联合组的总有效率分别为60.61%、74.29%、91.67%,组间比较差异具有统计学意义(P0.05)。治疗后,持续泵入美罗培南组、联合组的退热时间、肺部啰音消失时间、咳嗽消失时间均明显短于静脉滴注美罗培南组,且联合组明显低于持续泵入美罗培南组,组间比较差异具有统计学意义(P0.05)。治疗后,3组氧分压(pO_2)和氧合指数(OI)水平均显著升高,同组治疗前后比较差异具有统计学意义(P0.05);治疗后,联合组pO_2水平显著高于静脉滴注美罗培南组和持续泵入美罗培南组,组间比较差异具有统计学意义(P0.05);治疗后,持续泵入美罗培南组、联合组OI水平均显著高于静脉滴注美罗培南组,且联合组高于持续泵入美罗培南组,组间比较差异具有统计学意义(P0.05)。治疗后,3组患者血清中白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)、降钙素原(PCT)、C反应蛋白(CRP)水平均显著降低,同组治疗前后比较差异具有统计学意义(P0.05);治疗后,持续泵入美罗培南组、联合组血清炎症因子水平均显著低于静脉滴注美罗培南组,且联合组低于持续泵入美罗培南组,组间比较差异具有统计学意义(P0.05)。治疗后,3组APACHEⅡ评分均低于治疗前,同组治疗前后比较差异具有统计学意义(P0.05);治疗后,持续泵入美罗培南组、联合组的APACHEⅡ评分均显著低于静脉滴注美罗培南组,且联合组明显低于持续泵入美罗培南组,组间比较差异具有统计学意义(P0.05)。结论注射用美罗培南持续泵入联合注射用乌司他丁治疗重症肺炎具有较好的临床疗效,可有效改善患者病情,降低机体炎症反应,改善患者动脉血气指标,无严重并发症,具有一定的临床推广应用价值。     

金水宝胶囊联合舒洛地特治疗早期糖尿病肾病的临床研究

目的探讨金水宝胶囊联合舒洛地特治疗早期糖尿病肾病的临床效果。方法选取2015年1月—2018年1月河北大学附属医院收治的早期糖尿病肾病患者80例,随机分成对照组(40例)和治疗组(40例)。对照组口服舒洛地特软胶囊,1粒/次,2次/d。治疗组在对照组基础上口服金水宝胶囊,6粒/次,3次/d。两组患者均连续治疗4个月。观察两组患者临床疗效,同时比较治疗前后两组患者尿白蛋白排泄率(UAE)、24 h尿蛋白定量(24 h-UTP)值、血清肌酐(Cr)和尿素氮(BUN)水平、血脂、内皮功能、炎症及氧化应激指标和肾动脉血流参数。结果治疗后,对照组的总有效率为75.0%,显著低于治疗组的92.5%,两组比较差异具有统计学意义(P0.05)。治疗后,两组UAE、24 h-UTP值及血清Cr、BUN水平均显著降低(P0.05),且治疗组患者UAE、24h-UTP值及血清Cr、BUN水平明显低于对照组(P0.05)。治疗后,两组血清三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)、内皮素(ET)-1、C反应蛋白(CRP)浓度及外周血中性粒细胞与淋巴细胞比值(NLR)较治疗前均显著降低(P0.05),血清降钙素基因相关肽(CGRP)、超氧化物歧化酶(SOD)水平则均显著升高(P0.05),且治疗组患者上述血脂、内皮功能、炎症及氧化应激指标水平明显好于对照组(P0.05)。治疗后,两组患者肾动脉血流参数RI和PI值均显著降低(P0.05),且治疗组患者RI和PI值明显低于对照组(P0.05)。结论金水宝胶囊联合舒洛地特治疗早期糖尿病肾病能有效减少患者尿蛋白排泄,保护肾功能,纠正脂质代谢紊乱,改善微循环及肾脏血流动力学。     

肾衰宁颗粒联合缬沙坦治疗早期糖尿病肾病的临床研究

目的探讨肾衰宁颗粒联合缬沙坦治疗早期糖尿病肾病的临床疗效。方法选取汉中市铁路中心医院2016年8月—2018年6月收治的早期糖尿病肾病患者110例,随机分为对照组和治疗组,每组各55例。对照组患者口服缬沙坦胶囊,1粒/次,1次/d。治疗组在对照组基础上口服肾衰宁颗粒,1袋/次,3次/d。两组患者均连续治疗2个月。观察两组患者临床疗效,同时比较治疗前后两组患者氧化应激指标、血清胱抑素C(Cys-c)、晚期糖基化终产物(AGEs)、白介素-8(IL-8)、尿白蛋白尿排泄率(UAER)/24 h、尿素氮(BUN)、血肌酐(Scr)、空腹血糖(FPG)和糖化血红蛋白(HbA1c)水平。结果治疗后,对照组和治疗组临床有效率分别为78.18%、90.91%,两组比较差异具有统计学意义(P0.05)。治疗后,两组患者超氧化物歧化酶(SOD)水平显著上升(P0.05),晚期氧化蛋白产物(AOPP)、Cys-c、AGEs、IL-8、UAER/24 h、BUN、Scr、FPG和HbA1c水平显著下降,同组治疗前后比较差异具有统计学意义(P0.05);且治疗后治疗组这些指标水平明显好于对照组,两组比较差异具有统计学意义(P0.05)。结论肾衰宁颗粒联合缬沙坦可有效的减轻早期糖尿病肾病患者氧化应激及炎症反应,降低血糖,改善肾功能。     

老年重型胰腺炎患者机体凝血和抗凝系统的变化情况

目的探讨老年重型胰腺炎患者机体内凝血和抗凝系统的变化情况,分析凝血、抗凝指标对疾病发展程度的意义。方法收集2009年10月-2013年10月湖北医药学院附属太和医院收治的重型胰腺炎老年患者44例作为观察组,同期选择健康人群24例作为对照A组,同期选择老年轻型胰腺炎患者24例作为对照B组,对三组入选受试者进行血液样本采集,检测和记录标本凝血酶原时间(PT)、部分活化凝血酶原时间(APTT)、纤维蛋白原(FIB)D-二聚体。结果观察组PT、APTT、FIB和D-二聚体均明显高于对照A组和对照B组(P0.05)。结论老年重型胰腺炎患者机体内的凝血和抗凝系统明显异于常态时,可以直接影响到正常的微循环,同时凝血和抗凝系统指标患者病情发展的程度,有助于评估。