维生素A缺乏致小儿贫血的可能机制

小儿维生素A(VA)缺乏和贫血都是世界公共卫生问题。由于VA 缺乏不仅会引起小儿严重眼部疾病,还可导致小儿呼吸系统、免疫系统、消化系统、血液系统、生殖系统等多个系统多种疾病的发生发展;贫血对儿童的生长发育、免疫功能、学习能力等方面也有着重要影响。许多研究已证实VA缺乏可导致小儿贫血,但具体的机制目前尚无统一说法。以下就VA引起小儿贫血的病因机制做一综述。     

维生素A缺乏对儿童生长发育的影响及我国儿童维生素A营养现状

维生素A是儿童生长发育过程中不可缺少的微量营养素,其缺乏对儿童生长会有很大的影响.本文从维生素A缺乏对儿童生长发育、免疫功能方面的影响及我国儿童维生素A营养现状及干预措施作一综述.     

维生素A强化食用油干预对少年儿童免疫功能的改善作用

目的:观察维生素A(VA)强化食用油营养干预对少年儿童免疫功能的改善作用。方法:在四个不同地区选择VA缺乏的小学生作为研究对象,用VA含量为7500μg/kg的食用油对受试儿童进行5个月营养干预,观察血清VA水平、免疫球蛋白(IgA,IgG,IgM)和补体C3含量的变化。结果:干预组儿童的血清VA水平明显高于对照组,血清IgA和补体C3含量得到显著改善,但IgG,IgM含量与对照组未见明显差别。结论:VA强化食用油可以有效改善儿童的VA营养状况,提高其免疫功能。     

维生素A缺乏对儿童免疫功能的影响

本实验以2～7岁幼儿园儿童为研究对象进行膳食调查、体格检查及血液学分析。排除营养不良、近期感染等因素的影响。由于未发现维生素A(VA)缺乏体征,根据血清VA水平筛选出VA缺乏或不足(VA<0.0070mmol/L为缺乏,<0.011mmol/L为不足)和正常对照儿童(VA>0.011mmol/L)。于补充VA前后,检测免疫学指标。结果表明:VA缺乏对儿童IgG、IgA、IgM及PHA皮试等无明显影响;而对S-IgA、C_3,溶菌酶及PHA淋巴细胞转化,缺乏组和对照组相比,差异有显著性;经过补充VA三个月后,上述免疫指标均能恢复。由此表明:即便是VA亚临床缺乏,对免疫功能的影响亦是多方面的,经过短期改善VA摄入。低下的免疫功能是可逆转的。     

维生素A对实验动物T淋巴细胞亚群的影响

某些研究结果已证实,婴幼儿通常存在潜在维生素A(VA)缺乏的危险性。在局部地区进行VA干预性试验结果表明,接受VA强化的儿童中,呼吸道和消化道感染性疾病的发生率明显下降。这些临床观察说明,VA在免疫功能方面起着重要的作用,但VA和人体免疫反应之间的许多机制还不清楚。本实验的目的是观察VA对兔细胞免疫功能的影响,从而为探索VA和细胞免疫之间的关系提供实验基础。     

补充维生素A与铁对改善学龄前儿童贫血和免疫功能的影响

目的为观察学龄前儿童亚临床维生素A(VA)缺乏状态缺铁时,机体免疫功能的变化以及VA与铁同时补充对改善儿童铁营养状况和免疫功能的影响.方法检测北京农村270名3～7岁儿童血清VA含量和血红蛋白(Hb)、血清铁(SI)、运铁蛋白饱和度(TS)及血清铁蛋白(SF)后,将其分为正常、低 VA、低铁和低VA低铁4组,每组选40人,检测血清免疫球蛋白IgA、IgG、IgM 与白细胞介素-2(IL-2).然后将低VA低铁组儿童随机分为补铁组 (每日口服相当于30 mg元素铁的硫酸亚铁,连续8周)和补VA+铁组(口服VA胶丸12 500 IU /次,2次/周,连续8周;口服铁量同补铁组,连续8周),分别进行干预.干预后重复检测血清VA、血液铁生化指标和以上免疫指标,进行两组间比较,并与干预前比较. 结果低VA低铁组儿童血清IgM为(1 260±310) mg/L显著高于正常组的(1 0 7 0±170) mg/L.对其实施VA+铁联合干预后,血清TS为(26.5±8.6)%,明显高于补铁前的(16.2±1.6)%和单纯补铁组的(22.3±3.8)%;IL-2在VA与铁同时补充后为(2 78.9±117.7) ng/L,显著高于补充前的(161.6±90.3) ng/L和单纯补铁组的(189 .5 ±89.3)ng/L的水平;其他铁生化指标和免疫指标无明显变化.结论对存在亚临床VA缺乏状态的缺铁儿童实施一定剂量的VA+铁联合干预,对改善机体铁营养状况和免疫功能有明显作用.     

福建省5岁以下儿童维生素A缺乏流行病学调查

【目的】了解福建省5岁以下儿童维生素A(vitamin A，VA)缺乏现状及其影响因素。【方法】对儿童进行体检、病史询问、膳食调查和血清VA检测。【结果】福建省5岁以下儿童VA亚临床缺乏患病率为6．3％，可疑缺乏患病率为26．3％，未发现有临床表现的VA缺乏。亚临床VA缺乏的患病率存在地区差异，影响VA的缺乏因素有父母的文化程度、职业、家庭经济收入及摄入胡萝卜、深色蔬菜、蛋、动物肝脏、牛奶、水果、鱼肝油的量、近3个月是否有患腹泻、呼吸道感染、贫血等疾病。【结论】采取干预措施来改善儿童VA营养状况是非常必要的，也将是有效的。     

维生素A缺乏的危害研究进展

维生素 A( Vitamin A,VA)是人体所需的重要营养素之一 ,其主要功能是构成视觉细胞内的感光物质 ,对维持暗光下的视觉功能有重要作用 ,且可促进儿童身高和体重的增长。VA与机体的抗感染作用有关 ,曾被称为“抗感染维生素”。VA缺乏会引起免疫功能异常 ,导致许多感染性疾病的发生。近年来 ,随着对 VA在细胞和分子水平作用机制的进一步研究 ,VA引起了营养学家和分子生物学家的注意。本文就 VA缺乏与机体的免疫功能和感染性疾病之间的关系及其研究进展作一综述1　VA缺乏与亚临床 VA缺乏VA缺乏症是目前世界上主要的营养缺乏病之一 ,可分…     

甘肃省某农村地区7~12岁学龄儿童维生素A营养改善研究

目的 调查甘肃省某贫困农村地区7~12岁学龄儿童维生素A （vitamin A,VA）营养状况,对VA营养干预效果进行评价。方法 采用随机整群抽样的方法对甘肃省兰州市两贫困地区的396名7~12岁学龄儿童进行膳食调查、血清VA水平检测。干预组儿童进行VA营养饼干干预,对照组正常饮食,六个月后再次进行血清VA测定。结果 该地区7~12岁儿童膳食VA平均水平为328.45 μgRE,血清VA平均水平为433.19 μg/L,VA缺乏率为4.29%,VA边缘缺乏率为12.37%。干预六个月后,干预组儿童血清VA水平增长值为（44.03±6.48）μg/L,对照组儿童血清VA水平增长值为（6.65±4.34）μg/L,两组差异具有统计学意义（t=56.451,P<0.001）;干预后干预组儿童血清VA缺乏率为1.06%,对照组缺乏率为3.54%,两组差异无统计学意义（χ2=1.610,P=0.204）,干预组血清VA边缘缺乏率为3.53%,对照组血清VA边缘缺乏率为9.73%,差异有统计学意义（χ2=6.183,P=0.013）。结论 甘肃省某农村地区学龄儿童处于VA轻度缺乏状态,补充红棕榈油营养饼干能明显改善儿童VA营养缺乏的状况,这可能成为当地解决儿童VA缺乏问题的有效途径。     

学龄前儿童维生素A营养状况与常见感染性疾病的关系

维生素A(VA)缺乏(VAD)是由于膳食中所含VA或VA的前体物质不足,不能满足生长发育、日常生理功能的需要,以及因为疾病导致阶段性的需要量增加.目前世界上每年约有1.4亿学龄前儿童存在VAD问题[1].VAD是WHO确认的儿童常见四大营养缺乏病之一.在许多国家,特别是发展中国家,VAD与感染性疾病有密切关系.据估计,每年全世界由于VAD导致的不可逆性失明儿童中,有60%～80%死于合并的各种感染性疾病.VAD导致的感染以腹泻和严重呼吸道感染为主.同时,感染性疾病也会导致VAD,并且感染越严重,血清VA降低越明显.严重威胁学龄前儿童的健康.因此预防学龄前儿童VAD,及时进行有效的营养干预是非常重要的.     

Trends in meningococcal disease in Italy in 1988

Meningococcal disease in Italy decreased 15% in 1988 from the previous year (290 vs. 342 cases). The decline was particularly evident in military cases (1.7/100,000 in 1988 vs. 5/100,000 in 1987) reflecting the full coverage of bivalent serogroup (A + C) meningococcal polysaccaride vaccine in army recruits, achieved since January 1988. The highest proportion of cases was seen in people older than 25 years of age (25%). Serogroup C constituted 60% of the isolates, while 19% belonged to serogroup B. The proportion of strains resistant to sulphonamides was 45%, while 15% were resistant to Minocycline and none to Rifampin. Out of the five military cases, only one (due to serogroup C) was attributable to the vaccine failure. A single coprimary case, but no secondary cases occurred among civilians. These findings are consistent with the trends reported in Italy in the previous years.     

Benzene in blood and phenol in urine in monitoring benzene exposure in industry

Determinations of benzene concentration in blood and of phenol in urine were made by head-space gas chromatography techniques on samples taken near the end of the work day from two groups of workers potentially exposed to low levels of benzene in the work-place atmosphere. Preliminary results suggest that benzene in blood is more reliable than phenol tests for assessing both exposure and uptake of benzene. Normal values of phenol in urine (10 mg/liter or less) were found in nearly all those cases in which benzene was detected in the blood.     

2015年郑州市饮用水放射性水平状况调查

目的了解郑州市不同地区、不同季节、不同水源类型的放射性水平。方法分别于丰水期和枯水期采集郑州市区黄河水源水、井水源水、丹江口水源水、出厂水和末梢水各一份;以县为单位,每单位采集出厂水、末梢水、水库水、河水、井水各1份,按《生活饮用水生活标准检验方法》(GB/T 5750.13-2006)检测饮用水中总α和总β放射性水平,依据《生活饮用水卫生标准》(GB 5749-2006)进行判定。结果丰水期、枯水期水体总α、总β放射性水平均低于国家标准限值。结论郑州市不同水源类型均处于正常的天然放射性本底水平。     

Occupational stress in nurses in psychiatric institutions in Taiwan

Nurses are known to be exposed to occupational stress. However, occupational stress is not well documented for nurses in psychiatric institutions in Taiwan. A cross-sectional study was conducted to explore the work-related stress and risk factors of nurses in psychiatric institutions in Taiwan. A structured questionnaire was distributed to nurses at five state-owned psychiatric hospitals in Taiwan in 2001. Demographic information, working environment, and personal health status were inquired. Occupational stress was assessed based on the Chinese version of Job Content Questionnaire (JCQ). General health status and mental health were evaluated by the International Quality of Life Assessment Short Form-36 (IQOLA SF-36). A total of 573 questionnaires were disseminated to nurses and 518 (90.4%) were satisfactorily completed by nurses, including 408 female full-time nurses who had been in their current work for more than 6 months. In the past one month, 17.2% of nurses reported being under significant stress often or always. Assault episodes were reported by 45.1% of nurses in the past 6 months. Among the nurses, 16.9%, 25.2%, 50.0%, and 7.8% belong to the "High strain", "Low strain", "Active", and "Passive" groups, respectively. Perceived occupational stress was associated with young age, widowed/divorced/separated marital status, high psychological demand, low workplace support, and threat of assault at work. Lower general health score was associated with low job control, high psychological demand, and perceived occupational stress. A lower mental health score was associated with low job control, high psychological demand, low workplace support, and perceived occupational stress. We concluded that nurses in psychiatric institutions are under significant stress related to work factors.     

Changes in nursing administration in supporting transplantation in Brazil

This historical and bibliographic study aimed to understand how Nursing was organized to support care in transplantation. The HISA, LILACS, BDENF, PERIENF and DEDALUS databases were consulted, and thirteen references were found, ten of which were scientific articles, two were master's dissertations and one was a doctoral thesis. The span of time chosen for study ranges from the date of the first kidney transplant in Brazil (1965), to the date of publication of the last scientific article found in the databases mentioned above (2003). After reading these articles, the ones that were similar in topic were grouped together, thus creating the thematic axis for the presentation of the results. The results showed that the Nursing profession has played an important and active role in transplants ever since the first procedure in 1965.     

2019年中国肿瘤流行病学研究进展

恶性肿瘤已成为中国居民的主要死因之一。近些年来,中国政府积极推进肿瘤预防和控制领域的研究工作,取得了很大的进步。本文简要汇总中国在肿瘤流行病学领域的研究进展,具体包括2019年的肿瘤负担、癌症危险因素及其干预、筛查和早期发现、癌症防治专项行动(2019-2022年)方案等方面,以期为我国肿瘤防治工作的有效开展提供技术支撑和理论依据。     

2012年绵阳市蔬菜中农药残留状况

目的 了解绵阳市2012年市售蔬菜中农药残留情况,为食用蔬菜监管提供依据.方法 全部样品均按照GB/T 5009-2003的方法进行农药的残留检测.依据GB 2763-2005《食品中农药最大残留限量》进行判定.结果 2012年共检测蔬菜165份,农药检出率和超标率分别为72.12％和23.64％.豆类、根茎类、叶菜类、瓜果菜类和食用菌类蔬菜检测农药残留超标率分别为8.00％、23.53％、36.00％、5.26％和27.03％,差异有统计学意义(x2=11.41,P＜0.01).不同种类农药超标率差异有统计学意义(x2 =62.42,P＜0.01).夏季和冬季蔬菜农药超标率差异无统计学意义(x2=3.44,P＞0.05).结论 绵阳市叶菜类蔬菜中农药残留情况较为严重,应采取有效措施,加强蔬菜的监督管理,从源头禁止高毒农药的使用,加大蔬菜种植、销售环节的监测,确保市民食用蔬菜的安全.