The prematurity paradox of the small Indian baby

Prematurity in Indian births is modeled, based on the hypothesis that reduced protein and glucose and aminoacids and maternal anemia and preeclampsia lead to placental dysfunction which is also affected by metabolic disturbance and fetal circulation related to cellular growth and questions about genetics. There may be an ethnic propensity for early maturation of the fetus which affects the higher stillbirth rates and perinatal mortality. It was observed that among, for instance, black and Indian racial groups there may be meconium release and fetal distress. The significance is that physicians should increase antenatal surveillance before 40 weeks. Maternal nutrition should be advanced and hyperalimentation by cordocentesis. Other interventions such as glucose, oxygen, and aspirin administration are still very experimental. The evidence that velocity of growth is different and low birth weight is due to abnormal growth and shortened gestation is currently being researched among different ethnic groups. The discussion is concerned with reports of ethnic variation among Indian and Malay babies in Singapore and babies of French or African ancestry in France. In these studies findings were that the Indians and Malays in Singapore vs. the Chinese had higher mortality, and black African ancestry in mixed ancestry babies was related to higher infant mortality. Another study on neonatal mortality in India led to the recommendation that 2000 gm be established as the limit for defining low birth weight. In the 1501- 2000 gm birth weight groups, 30-45% are preterm, and the remainder are term or postterm. Low birth weight may transcend generations in India even with emigration. Experimental studies show that intrauterine weight is related to placental volume. Reduced growth and lower fetal insulin/glucose ratio with elevated fetal glycine/valine ratio was found to be related to reduced glucose supply among fetuses with fetal hypertriglyceridemia. Fat seems to be lacking among low birth weight fetuses. Studies of somatomedin and somatostatin in metabolism are helping to provide greater understanding of fetal growth processes.     

Maternal-neonatal serum vitamin A concentrations

Prevention of neonatal vitamin A deficiency is related to the adequacy of maternal vitamin A stores. In this study we investigated maternal and cord serum vitamin A and retinol-binding protein (RBP) values in an Indian population including, for the first time, clinically vitamin A-deficient mothers. Twenty-eight maternal-neonatal pairs were selected from maternal cohorts of high socioeconomic status without clinical evidence of vitamin A deficiency (group I) and low socioeconomic status with conjunctival xerosis and Bitot's spots (group II). Maternal education, caloric and vitamin A intakes, weight, height, hemoglobin, and birth weight were significantly lower in group II. Serum vitamin A levels were significantly higher in group I mothers and newborns as were RBP levels in group I mothers. However, a significant difference between groups I and II in cord blood RBP was not observed. Upon correlation of maternal vitamin A levels with cord blood vitamin A levels, a logarithmic relationship was revealed, suggesting saturable transplacental transport of vitamin A.     

维生素A与哮喘关系的研究进展

维生素A缺乏是哮喘发病的危险因素之一.维生素A具有拮抗气道氧化性损伤、促进气道损伤的修复、抑制气道高反应、诱导免疫耐受、调节气道炎症等功能.维生素A用于哮喘防治成为研究热点,但其效益性仍存在争议.维生素A的受体广泛表达、信号通路复杂,维生素A与哮喘发病相关机制有待更深入的研究.目前,维生素A用于哮喘防治的临床研究已有报道,但结果尚不一致.哮喘是一种由环境和遗传因素共同作用的多基因遗传病,今后维生素A用于哮喘防治的基础和临床研究可结合遗传和环境的群体差异.该文就维生素A与哮喘关系的研究进展进行综述.     

The effect of vitamin A status in children treated for cancer

Chemotherapy for cancer can cause immunocompromise. The authors speculated that children with cancer and low vitamin A plasma levels were more susceptible to cancer treatment-related complications than children who are not vitamin A deficient. A cohort of 49 children with cancer were followed from diagnosis until death or for at least 5 years. Plasma retinol levels were determined at diagnosis. Complications of treatment were recorded. Children with low retinol levels at diagnosis tended to have more chance to develop febrile neutropenia (p = .052). Children with fever had lower mean vitamin A levels at diagnosis than those who did not suffer febrile episodes. In a childhood population with a high prevalence of vitamin A deficiency, routine vitamin A assessment and supplementation in children with cancer appears indicated.     

维生素 A 水平与儿童肺炎支原体感染的关系

目的探讨维生素A(VA)水平与肺炎支原体(MP)感染的相关性。方法随机选取2015年3月—2015年12月因呼吸道急性感染性疾病住院的0~12岁儿童为研究对象。采用高效液相色谱法(HPLC)检测血清VA水平,聚合酶链反应(PCR)检测鼻咽拭子MP-DNA,酶联免疫吸附法(ELISA)检测血清MP-Ig M。分析和比较亚临床VA缺乏(SVAD)、可疑亚临床维生素A缺乏(SSVAD)和VA正常患儿间MP感染情况。结果 600例患儿中SVAD 83例(13.83%),SSVAD193例(32.17%),1岁、1~3岁、6岁以及~6岁组间SVAD及SSVAD发生率的差异有统计学意义(P均0.001),其中1岁婴儿SVAD及SSVAD发生率最高,分别为26.36%和49.10%。600例患儿中MP阳性病例201例(33.5%),其中SVAD 57例(28.35%),SSVAD 70例(34.83%);MP阳性患儿的SVAD发生率高于阴性患儿,差异有统计学意义(P0.001)。201例MP阳性患儿不同年龄组间SVAD、SSVAD以及VA正常儿童分布的差异有统计学意义(P=0.003),1岁婴儿SVAD发生率(48.39%)较高。结论 SSVAD、SVAD以1岁婴儿最多,SVAD与儿童MP感染可能相关。     

维生素A在小儿呼吸道感染性疾病中的应用

维生素A作为一种最早被认识并应用于临床的维生素 ,有维持上皮完整性、提高机体免疫力及抗感染的作用 ,被称为“抗感染维生素”而用于防治小儿呼吸道感染性疾病。但是它的缺乏与感染之间的关系及其抗感染的机制尚没有统一的结论。该文就维生素A与呼吸道感染性疾病的相关性及其在呼吸道感染性疾病中的应用综述如下。     

Risk of vitamin A toxicity from candy-like chewable vitamin supplements for children

Numerous vitamin supplements are available over-the-counter to the general public. Some such supplements are available as candy-like chewable preparations to encourage consumption by children. We report 3 cases of overdose of such preparations. Each patient had taken an estimated 200,000 to 300,000 IU of vitamin A. Their circulating vitamin A (retinol and retinyl palmitate) concentrations were monitored over a 6-month period. There were no clinical or biochemical complications noted. However, there were marked increases in both retinol and retinyl palmitate concentrations above age-related reference ranges. In particular, it took 1 to 3 weeks for the serum retinol concentrations to peak and many months for them to normalize. Parents should be warned about the dangers of excessive vitamin consumption. Clinicians should be aware of the late peak in serum retinol concentrations, which may lead to late complications of vitamin A overdose.