巯基棉富集尿镉的火焰原子吸收光谱法

本文报道了用巯基棉富集,盐酸溶液解吸,直接测定尿中镉的火焰原子吸收光谱法。巯基棉富集尿镉的pH为5.0～6.0,最佳解吸酸度为0.2mol/L HCl。该法样品不需消化处理,操作简便,其检测限为0,22μg/L,回收率为99.8～101.4%,变异系数为1.2～4.9%。本法可用于生物监测和职业病诊断。     

水中痕量铅、镉的在线螯合树脂富集火焰原子吸收测定法

目的探讨天然水体中痕量铅、镉的测定方法。方法利用蠕动泵与火焰原子吸收的提升作用,让试液先通过树脂柱再进入火焰,调节试液酸度为pH=5．7,使试液中痕量的铅、镉富集在树脂柱上,然后让1．5mol／LHNO3溶液通过树脂柱,将铅、镉以6．0ml／min快速洗脱并喷入火焰中,记录瞬时峰高。结果在线螯合树脂富集火焰原子吸收法测定水中铅、镉的检出限分别为0．500、0．02μg／L,比单纯火焰原子吸收法检出限(均为10．0μg／L)分别降低2—3个数量级,相对标准偏差分别为2．3％,1．7％,精密度好于石墨炉法,回收率为94％-104．4％。结论该方法适合对天然水体中痕量铅、镉的火焰法快速测定。     

大连市12种海产贝螺生物体中铅和镉含量的调查

目的测定大连沿海中鲍鱼、海螺、牡蛎等12种海产贝螺生物体中铅、镉的含量,分析贝螺生物体富集铅镉的能力。方法采用高氯酸-硝酸消化法消解试样,采用火焰原子吸收光谱法(FAAS)测定生物体样品中铅、镉的含量。结果FAAS法测定贝螺生物体中铅的含量为0.1323～2.199μg/g,镉的含量为0.1983～3.613μg/g。且同一生物体不同组织器官对铅、镉积累能力存在明显差异。结论贝螺生物体不同种属间铅镉含量存在差异,且常见的可以容易区分的内脏和肉的贝螺的不同组织对铅、镉富集能力存在差异。     

微波消解-石墨炉原子吸收光谱法测定血和尿中的铅和镉

目的建立微波消解-石墨炉原子吸收光谱法测定血和尿中铅和镉含量的方法,为临床铅镉中毒提供诊疗依据。方法取0.50 ml血液和尿液,在HNO3/H2O2消解剂中微波消解5 min,然后以硫酸铵-磷酸二氢铵混合溶液为基体改进剂,采用石墨炉原子吸收光谱法对消解液中的铅镉含量进行测定。结果铅、镉在分别在0.0~160μg/L和0.0~16.0μg/L范围内线性良好(相关系数分别为铅0.9993,镉0.9987),方法检出限(3 s/b)分别为0.36μg/L和3.24μg/L。加标回收率在97.8%~103.0%之间,测定值的相对标准偏差(n=6)在1.76%~6.81%之间。结论该方法快速灵敏,精密度和准确度均符合要求,可为临床诊断铅镉中毒提供一个简便准确的检测方法。     

水中痕量锰的浊点萃取-火焰原子吸收光谱测定法

目的建立水中痕量锰的浊点萃取-火焰原子吸收光谱测定方法。方法选用非离子表面活性剂聚乙二醇辛基苯基醚（Triton X-114）作为浊点萃取剂,1-（2-吡啶偶氮）-2-萘酚（PAN）作为螯合剂,富集、分离水中痕量锰,采用火焰原子吸收光谱法进行检测。结果在优化的实验条件下,采用该方法测定50ml样品,结果显示,锰的检测限为0.28μg/L,富集倍率为65倍,线性范围为0.93－120μg/L,r=0.999,回收率在98.0%－101.5%之间,相对标准偏差为2.17%。结论该方法具有简单、安全、快捷、灵敏、高效的特点,适用于环境水样中痕量锰的测定。     

微波消解-石墨炉原子吸收光谱法测定土壤中铅和镉

[目的]建立微波消解-石墨炉原子吸收光谱测定土壤中铅和镉的分析方法。[方法]土壤样品研磨过100目筛,用硝酸-氢氟酸-过氧化氢混合消解液微波消解后,石墨炉原子吸收光谱测定。[结果]铅浓度为5.0~40.0μg/L、镉浓度为0.20~2.00μg/L时,石墨炉原子吸收光谱测定土壤中铅和镉的方法线性良好,相关系数均为0.9999。铅和镉的方法定量检出限分别为5.0、0.040mg/kg。加标回收率为90.0%~110.0%,相对标准偏差为4.1%~6.9%,标样的测定结果在不确定度范围内。[结论]该方法简便、快速,基体干扰少,结果准确,适用于土壤中铅、镉含量的测定。     

微波消解-石墨炉原子吸收光谱法测定蔬菜水果中铅、镉、镍、铬含量的探讨

目的建立使用微波消解样品,石墨炉原子吸收光谱法测定蔬菜和水果中铅、镉、镍、铬的方法。方法样品加8 ml硝酸,预消化1 h左右,再经微波消解,并优化灰化原子化温度,以氯化钯-磷酸二氢铵混合溶液为基体改进剂测定铅、镉、镍含量,铬检测不加基改,用石墨炉原子吸收光谱法测定。结果铅、镉、镍、铬的线性范围分别在0~50μg/L、0~4μg/L、0~40μg/L、0~16μg/L,方法检出限分别为0.413μg/L、0.043μg/L、0.154μg/L和0.130μg/L。铅、镉、镍、铬标准曲线相关系数分别为0.9958、0.9973、0.9984和0.9992,相对标准偏差为0.85%~3.87%,样品加标回收率为91.5%-101.8%。结论该方法精密度高,样品加标回收率好,可作为检测蔬菜水果中铅、镉、镍、铬含量快捷、可靠的方法。     

微波消解-石墨炉原子吸收法测定滩涂中的铅和镉

目的:建立滩涂中铅和镉的微波消解-石墨炉原子吸收光谱测定方法。方法:以磷酸二氢铵-硝酸镁作基体改进剂,采用硝酸-氢氟酸进行微波消解,利用塞曼扣背景,石墨炉原子吸收法测定滩涂中的铅和镉含量。结果:铅和镉分别在2.0μg/L～50.0μg/L和0.2μg/L～5.0μg/L范围内具有良好的线性,相关系数大于0.999,加标回收率为90%～103%,RSD均小于5.0%。结论:建立的方法具有简便、灵敏、准确的特点,适合于高盐滩涂中铅镉的测定。     

微波消解-石墨炉原子吸收法测定小海鲜产品中的铅和镉

目的:建立小海鲜产品中铅和镉的微波消解-石墨炉原子吸收光谱测定方法。方法:以磷酸二氢铵-硝酸镁作基体改进剂,采用硝酸进行微波消解,利用塞曼扣背景,石墨炉原子吸收法测定小海鲜产品中的铅和镉含量。结果:铅和镉分别在2.0μg/L～50.0μg/L和0.2μg/L～5.0μg/L范围内具有良好的线性,相关系数大于0.999,铅镉的的最低检出限为5.4μg/kg湿重和0.31μg/kg湿重,加标回收率为90.0%～102.0%,RSD均小于5.0%,采用本法对国家标准物质贻贝GBW08571进行测定,经t检验(P>0.05),测定结果与标准值无显著性差异。结论:建立的方法具有简便、灵敏、准确的特点,适合于高盐海产品中铅镉的测定。     

磷酸氢铈纳米吸附剂预富集-火焰原子吸收法 测定水中痕量铅

摘要:目的　建立磷酸氢铈（CeP）一维纳米吸附剂预富集-火焰原子吸收法测定水体中痕量铅的新方法。方法　用10 mg CeP 对pH为2～9的200 ml水样中的Pb2+吸附富集30 min,抽滤后再用4.00 ml 2 mol/L的硝酸溶液解吸60 min,用火焰原子吸收法测定解吸液中的Pb2+。结果　该方法测定Pb2+的线性范围为10～400 μg/L,回归方程为y＝0.0011x + 0.0043,线性相关系数r＞0.999,检出限为1.14 μg/L,相对标准偏差为1.12%（n＝9,80 μg/L）,加标回收率为99.8%～107.5%。结论　本方法线性范围宽,灵敏度高,准确度和精密度良好,操作条件简单,测定成本低,可应用于环境水样中痕量铅的测定。     

女性生殖器结核的临床表现及腹腔镜与宫腔镜检查特点分析

目的探讨女性生殖器结核(FGT)的临床表现,以及在腹腔镜、宫腔镜检查的表现特点,提高临床对FGT的诊断和鉴别诊断能力。 方法选择2010年1月至2016年12月,于首都医科大学附属北京妇产医院妇科微创中心进行腹腔镜和(或)宫腔镜检查,并经抗酸染色法和(或)活组织病理学检查,以及腹水培养病原学检查确诊为FGT的33例患者为研究对象。其年龄为17～73岁,平均为(31.4±5.6)岁。采用回顾性分析方法,收集所有患者的不孕、腹部异常症状、月经改变等临床表现,胸部X射线摄片、CT检查等影像学辅助检查结果,以及腹腔镜探查、宫腔镜检查、活组织病理学检查结果,并进行统计学分析。对于患者的不孕、腹部异常症状、月经改变等临床表现发生率,以及腹腔镜、宫腔镜检查结果所占比例等计量资料,采用率(%)表示。 结果①本研究33例FGT患者的临床表现中,以不孕最为多见,为21例(63.6%,21/33)。其他临床表现包括：下腹胀痛为7例(21.2%,7/33),腹水为5例(15.2%,5/33),盆腔包块为5例(15.2%,5/33),月经量过少或闭经为4例(12.1%,4/33),月经不规律为2例(6.1%,2/33),痛经为1例(3.0%,1/33),绝经后出血为1例(3.0%,1/33)。②本研究33例FGT患者中,经活组织病理学检查确诊为FGT者为26例,其中,17例确诊为输卵管结核,3例确诊为输卵管结核合并卵巢结核,6例确诊为子宫内膜结核,病理学诊断FGT阳性率为78.8%(26/33);1例(3%,1/33)抗酸染色结果呈强阳性,确诊为输卵管结核;4例(12.1%,4/33)经腹部X射线摄片检查确诊为输卵管结核;2例(6.1%,2/33)经诊断性抗结核治疗后,确诊为输卵管结核。③本研究33例FGT患者的影像学辅助检查结果提示,该检查对诊断FGT的符合率为21.2%(7/33)。④本研究33例FGT患者的腹腔镜检查结果如下：合并腹水者为7例(21.2 %,7/33),腹膜粟粒样改变者为16例(48.5%,16/33),输卵管积水与周围组织包裹成团者为10例(30.3%,10/33),输卵管增粗,呈串珠样、腊肠样改变者为13例(39.4%,7/33),输卵管伞端有黄色脓液流出者为1例(3.0%,1/33),卵巢呈苍白样改变、质硬者为2例(6.1%,2/33),盆、腹腔内可见干酪样坏死物者为13例(39.4%,13/33)。⑤本研究33例FGT患者中,25例因合并不孕或月经改变,接受腹腔镜检查的同时进行宫腔镜检查的结果显示,6例(24.0%,6/25)宫角局部子宫内膜增厚不平,输卵管开口细小;1例(4.0%,1/25)子宫内膜变薄,呈不规则苍白样改变;4例(16.0%,4/25)为宫腔黏连,其中1例(4.0%,1/25)可见干酪样钙化灶;其余14例(56.0%,14/25)宫腔镜检查结果均为正常宫腔形态。 结论腹腔镜和(或)宫腔镜检查可清晰显示FGT病灶的部位、大小、形态及病变周围情况,对于FGT的诊断和鉴别诊断具有重要意义。     

Raccoons and skunks as sentinels for enzootic tularemia

We analyzed sera from diverse mammals of Martha's Vineyard, Massachusetts, for evidence of Francisella tularensis exposure. Skunks and raccoons were frequently seroreactive, whereas white-footed mice, cottontail rabbits, deer, rats, and dogs were not. Tularemia surveillance may be facilitated by focusing on skunks and raccoons.     

Multidisciplinary and Evidence-based Method for Prioritizing Diseases of Food-producing Animals and Zoonoses

To prioritize 100 animal diseases and zoonoses in Europe, we used a multicriteria decision-making procedure based on opinions of experts and evidence-based data. Forty international experts performed intracategory and intercategory weighting of 57 prioritization criteria. Two methods (deterministic with mean of each weight and probabilistic with distribution functions of weights by using Monte Carlo simulation) were used to calculate a score for each disease. Consecutive ranking was established. Few differences were observed between each method. Compared with previous prioritization methods, our procedure is evidence based, includes a range of fields and criteria while considering uncertainty, and will be useful for analyzing diseases that affect public health.     

Roads, railways, and childhood cancers

Study OBJECTIVES: To locate geographical sources of engine exhaust emissions in Great Britain and to link them with the birth addresses of children dying from cancer. To estimate the cancer initiating roles of nearby roads and railways and to measure effective ranges. DESIGN: Birth and death addresses of all children born between 1955 and 1980 in Great Britain, and dying from leukaemia or other cancer during those years, were linked to locations of railway stations, bus stations, ferry terminals, railways, roads, canals, and rivers. Nearest distances to births and deaths were measured, and migration data relating to children who had moved house were analysed. Excesses of close to hazard birth addresses, compared with close to hazard death addresses, indicate a high prenatal or early postnatal risk of cancer initiation. SETTING AND SUBJECTS: Child cancer birth and death addresses and their map references were extracted from an earlier inquiry. Map references of putative hazards were downloaded from the Ordnance Survey national digital map of Great Britain. These data are recorded to a precision of one metre and have ground accuracies around 20 metres. MAIN RESULTS: Significant birth excesses were found within short distances of bus stations, railway stations, ferries, railways, and A,B class roads, with a relative risk of 2.1 within 100 m, tapering to neutral after 3.0 km. About 24% of child cancers were attributable to these joint birth proximities. Roads exerted the major effect. CONCLUSIONS: Child cancer initiations are strongly determined by prenatal or early postnatal exposures to engine exhaust gases, probably through maternal inhalation and accumulation of carcinogens over many months. The main active substance is probably 1,3-butadiene.     

Fluoride induces endoplasmic reticulum stress and inhibits protein synthesis and secretion

BACKGROUND: Exposure to excessive amounts of fluoride (F(-)) causes dental fluorosis in susceptible individuals; however, the mechanism of F(-)-induced toxicity is unclear. Previously, we have shown that high-dose F(-) activates the unfolded protein response (UPR) in ameloblasts that are responsible for dental enamel formation. The UPR is a signaling pathway responsible for either alleviating endoplasmic reticulum (ER) stress or for inducing apoptosis of the stressed cells. OBJECTIVES: In this study we determined if low-dose F(-) causes ER stress and activates the UPR, and we also determined whether F(-) interferes with the secretion of proteins from the ER. METHODS: We stably transfected the ameloblast-derived LS8 cell line with secreted alkaline phosphatase (SEAP) and determined activity and localization of SEAP and F(-)-mediated induction of UPR proteins. Also, incisors from mice given drinking water containing various concentrations of F(-) were examined for eucaryotic initiation factor-2, subunit alpha (eIF2alpha) phosphorylation. RESULTS: We found that F(-) decreases the extracellular secretion of SEAP in a linear, dose-dependent manner. We also found a corresponding increase in the intracellular accumulation of SEAP after exposure to F(-). These changes are associated with the induction of UPR proteins such as the molecular chaperone BiP and phosphorylation of the UPR sensor PKR-like ER kinase, and its substrate, eIF2alpha. Importantly, F(-)-induced phosphorylation of eIF2alphawas confirmed in vivo. CONCLUSIONS: These data suggest that F(-) initiates an ER stress response in ameloblasts that interferes with protein synthesis and secretion. Consequently, ameloblast function during enamel development may be impaired, and this may culminate in dental fluorosis.     

Dihydropteroate synthase gene mutations in Pneumocystis and sulfa resistance

Pneumocystis pneumonia (PCP) remains a major cause of illness and death in HIV-infected persons. Sulfa drugs, trimethoprim-sulfamethoxazole (TMP-SMX) and dapsone are mainstays of PCP treatment and prophylaxis. While prophylaxis has reduced the incidence of PCP, its use has raised concerns about development of resistant organisms. The inability to culture human Pneumocystis, Pneumocystis jirovecii, in a standardized culture system prevents routine susceptibility testing and detection of drug resistance. In other microorganisms, sulfa drug resistance has resulted from specific point mutations in the dihydropteroate synthase (DHPS) gene. Similar mutations have been observed in P. jirovecii. Studies have consistently demonstrated a significant association between the use of sulfa drugs for PCP prophylaxis and DHPS gene mutations. Whether these mutations confer resistance to TMP-SMX or dapsone plus trimethoprim for PCP treatment remains unclear. We review studies of DHPS mutations in P. jirovecii and summarize the evidence for resistance to sulfamethoxazole and dapsone.     

Limited Dissemination of Extended-Spectrum β-Lactamase– and Plasmid-Encoded AmpC–Producing Escherichia coli from Food and Farm Animals,Sweden

Extended-spectrum β-lactamase (ESBL)– and plasmid-encoded ampC (pAmpC)–producing Enterobacteriaceae might spread from farm animals to humans through food. However, most studies have been limited in number of isolates tested and areas studied. We examined genetic relatedness of 716 isolates from 4,854 samples collected from humans, farm animals, and foods in Sweden to determine whether foods and farm animals might act as reservoirs and dissemination routes for ESBL/pAmpC-producing Escherichia coli. Results showed that clonal spread to humans appears unlikely. However, we found limited dissemination of genes encoding ESBL/pAmpC and plasmids carrying these genes from foods and farm animals to healthy humans and patients. Poultry and chicken meat might be a reservoir and dissemination route to humans. Although we found no evidence of clonal spread of ESBL/pAmpC-producing E. coli from farm animals or foods to humans, ESBL/pAmpC-producing E. coli with identical genes and plasmids were present in farm animals, foods, and humans.     

Amoeba-resisting bacteria and ventilator-associated pneumonia

To evaluate the role of amoeba-associated bacteria as agents of ventilator-associated pneumonia (VAP), we tested the water from an intensive care unit (ICU) every week for 6 months for such bacteria isolates; serum samples and bronchoalveolar lavage samples (BAL) were also obtained from 30 ICU patients. BAL samples were examined for amoeba-associated bacteria DNA by suicide-polymerase chain reaction, and serum samples were tested against ICU amoeba-associated bacteria. A total of 310 amoeba-associated bacteria from 10 species were isolated. Twelve of 30 serum samples seroconverted to one amoeba-associated bacterium isolated in the ICU, mainly Legionella anisa and Bosea massiliensis, the most common isolates from water (p=0.021). Amoeba-associated bacteria DNA was detected in BAL samples from two patients whose samples later seroconverted. Seroconversion was significantly associated with VAP and systemic inflammatory response syndrome, especially in patients for whom no etiologic agent was found by usual microbiologic investigations. Amoeba-associated bacteria might be a cause of VAP in ICUs, especially when microbiologic investigations are negative.     

Effect of Protein-Rich Breakfast on Subsequent Energy Intake and Subjective Appetite in Children and Adolescents: Systematic Review and Meta–Analysis of Randomized Controlled Trials

Breakfast has been labeled “the most important meal of the day”, especially for children and adolescents. Dietary protein intake may benefit and regulate appetite and energy balance. However, few meta–analyses have been conducted to examine the effect of protein–rich (PR) breakfast on both children and adolescents. This meta–analytic study was conducted to examine the effect of consuming a PR breakfast on short–term energy intake and appetite in children and adolescents. PubMed, Embase, Cochrane Central Register of Controlled Trials, China Biology Medicine disc (CBM), and China National Knowledge Infrastructure (CNKI) were searched for randomized controlled trials (RCTs) published in January 1990–January 2021. The inclusion criteria applied were RCTs in children and adolescents (7–19 year) comparing PR breakfast consumption with normal protein (NP)/traditional breakfast consumption. Finally, ten studies were included in the analysis, eight studies examined the effect of consuming PR breakfast on SEI (n = 824), and nine studies examined the effect on appetite (fullness = 736, hunger = 710). Our meta-analysis using the random–effects model shows that participants assigned to consume PR breakfast had lower SEI (MD, −111.2 kcal; 95% CI: −145.4, −76.9), higher fullness (MD, 7.4 mm; 95% CI: 6.0, 8.8), and lower hunger (MD, −8.5 mm; 95% CI: −9. 7, −7.3) than those assigned to consume NP/traditional breakfast. However, there was considerable inconsistency across the trial results. Our review suggests that the consumption of PR breakfast could be an excellent strategy for weight management by declining SEI and suppressing appetite, and provides new evidence of the relationship between energy balance and obesity. However, since most eligible studies were of low quality, the results ought to be interpreted cautiously.