糖尿病性心血管病变与血清微量元素铁、铬、锰水平的相关性研究

本文研究糖尿病并发心血管病变时血清脂类、脂类过氧化产物与微量元素水平的相关性,结果发现:血清微量元素铁(Fe)与总胆固醇(T—ch)水平呈负相关,与水溶性荧光物质(WSFS)呈正相关;血清微量元素锰(Mn)与极低密度脂蛋白—胆固醇(VLDL—ch)呈负相关,与丙二醛(MDA)呈正相关;微量元素铬(Cr)与高密度脂蛋白—胆固醇(HDL—ch)呈正相关。提示:微量元素Fe、Cr、Mn为糖尿病性心血管病变的易患元素。     

低角度青少年特发性脊柱侧凸女性患者的骨密度分析

目的分析低角度青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)女性患者的骨密度(BMD)和骨矿含量(BMC),探讨其与年龄、生长发育、人体测量学和侧凸角度等的相关性。方法研究对象为218例Cobb角15～40°的女性AIS患者。运用双能X线骨密度吸收仪测定非优势侧股骨颈和腰椎的BMC/BMD。探讨这两个部位的BMC/BMD与患者的年龄、生长发育、人体测量学和侧凸角度等的相关性。结果所有患者的年龄平均为(13.4±1.4)岁,Cobb角平均为(28.3±6.2)°。股骨颈BMD平均为(0.827±0.103)g/cm2,腰椎BMD平均为(0.887±0.124)g/cm2,显著低于同龄健康女性儿童;股骨颈BMC平均为(3.49±0.56)g,腰椎BMC平均为(29.78±7.37)g。患者的BMC/BMD与Cobb角无显著相关,而与体重、身高、Risser征、月经状况、BMI和年龄显著相关。逐步回归分析显示,体重和年龄是影响患者BMD的主要因素。结论低角度女性AIS患者存在全身性的骨量减低,且与Cobb角无显著相关,而与生长发育和人体测量学相关指标显著相关。这提示AIS患者的骨量减低与生长发育和低体重有关。     

高效液相色谱法测定去氧氟尿苷含量及其有关物质

目的 用高效液相色谱法（HPLC法）测定去氧氟尿苷的含量及其有关物质。方法 采用Diamonsil C—粒（250mm×4．6mm，5μm），流动相为乙腈-水（1：1），检测波长为269nm，流速为0．8mL／min。结果 去氧氟尿苷质量浓度在10．0～200．4μg／mL范围内与峰面积线性关系良好，r：0．9999（n：5），平均回收率为100．2％，RSD=0．14％。结论 HPLC法简便、准确，专属性好，灵敏度高，可用于去氧氟尿苷含量及有关物质的测定。     

健康儿童血浆游离氨基酸与体格生长的研究

本文采用丹酰氯聚酰胺薄层分析法研究了65名3～7岁健康儿童的血浆游离氨基酸,研究其与体格生长的关系.结果表明:赖氨酸,甘氨酸,羟脯氨酸,与年龄别身高、体重和身高别体重百分位成正相关.并有显著意义.异亮氨酸.赖氨酸.甘氨酸在营养优组中显著高于差组.提示血浆游离氨基酸对健康学龄前儿童的体格生长发挥重要的生理作用.     

经咽旁入路选择性切除大鼠垂体前叶的研究

目的研究经咽旁入路选择性的切除大鼠垂体前叶，以制备大鼠垂体前叶激素缺乏模型如生长激素（GH）缺乏模型。方法经腹侧咽旁入路，运用显微神经外科技术经基蝶骨底选择性地切除垂体前叶。然后采用竞争免疫沉淀法检测大鼠生长激素的含量，术后统计死亡率、成功率。结果切除垂体前叶后大鼠的死亡率为26．7％，成活率为73．3％，全切率为91％；成功制备大鼠模型的GH显著低于假手术组和对照组。结论运用显微外科技术可以成功的选择性的切除大鼠垂体前叶，制备出垂体前叶激素如生长激素缺乏的动物模型。     

重组人生长激素对荷人胃癌裸鼠移植瘤血管内皮生长因子表达的影响

目的研究重组人生长激素（rhGH）对生长激素受体（GHR）不同表达状态裸鼠人胃癌移植瘤生长及血管内皮生长因子（VEGF）表达的影响。方法采用免疫细胞化学染色法筛选出GHR阳性和阴性表达的细胞株各1株，分别接种于24只裸鼠皮下。将两种细胞接种裸鼠均随机分为对照组（0．9％NaCl，0．2ml／d）、低剂量rhGH组（0．5U·kg^-1·d^-1，0．2ml／d）和高剂量rhGH组（2．5U·kg^-1·d^-1，0．2mL／d）3组，每组8只，各组均连续给药14d，观察并记录裸鼠体重和肿瘤体积变化；采用酶联免疫吸附法测定各组裸鼠血清VEGF含量，免疫组织化学方法检测胃癌组织中VEGF蛋白表达，RT-PCR方法检测胃癌组织VEGFmRNA水平变化。结果筛选出GHR阳性表达的人胃癌细胞株SGC-7901和阴性表达的MKN-45。对于GHR^＋SGC-7901接种裸鼠，rhGH给药组皮下移植瘤体积较对照组增大（P〈0．05），且高剂量rhGH组促增长效应最为显著（P〈0．05），3组间体重差异无统计学意义（P〉0．05）；高剂量rhGH组的血清VEGF浓度为（252．94±15．32）ng／L，明显高于对照组的（49．94±5．73）ng／L和低剂量rhGH组的（167．60±9．54）ng／L（P〈0．05）；对照组VEGF表达为中度阳性，rhGH给药组呈强阳性；高剂量rhGH组肿瘤组织中VEGFmRNA相对表达量为0．6470±0．0447，明显高于对照组的0．3230±0．0258和低剂量rhGH组的0．4120±0．0351（P〈0．05）。对于GHR—MKN-45接种裸鼠，rhGH给药组体重明显大于对照组（P〈0．05）；肿瘤体积大小、血清VEGF水平、肿瘤组织VEGF蛋白及mRNA表达，3组间差异均无统计学意义（P〉0．05）。结论rhGH能促进GHR阳性表达的SGC-7901移植瘤生长，并促进VEGF表达增高；对于GHR阴性的MKN-45移植瘤，则没有表现出明显的促肿瘤生长及促VEGF表达效应。GHR存在可能是rhGH影响VEGF分泌的关键靶点。     

An approach to protein restriction in children with renal insufficiency

Children with mild to moderate renal insufficiency may be at an increased risk for developing glomerulosclerosis and subsequent renal failure. Low protein diets (LPD) have been shown to delay the progression of renal insufficiency in laboratory animals and may be of benefit in adult humans. The nutritional costs of a LPD in adults are reportedly minimal. We review the protein and caloric requirements of growing children and discuss the potential harmful effects and benefits of an LPD in this population. We also discuss dietary adherence and the difficulty of designing an LPD for children. We conclude that the protein content of a typical American diet can safely be reduced to, but not below, the recommended daily allowance for protein if diets are carefully planned, patients and their parents extensively counseled, and if dietary supplements are given to help meet the caloric and vitamin-mineral nutrient needs of growing children. In addition, ongoing nutritional assessment, counseling, and frequent monitoring of growth, diet and biochemical indicators of protein status are essential for maintaining the health of these children.     

Pyridinium crosslinks of collagen as a marker of bone resorption rates in children and adolescents: Normal values and clinical application

The aim of our study was to establish normal values of urinary pyridinoline (Pyr) and deoxypyridinoline (DPyr) excretion for children aged 3–18 years, examine the biological variability of the marker, and assess its clinical value for pediatric patients with growth hormone deficiency. Pyr and DPyr was measured in first void urine samples from 692 healthy subjects (340 boys, 352 girls) by high-performance liquid chromatography. At sampling, age, body height, and weight was recorded for all individuals. Short-term variability in crosslinks excretion was examined in four healthy children. The clinical value of the marker was studied in seven patients with growth hormone (GH) deficiency. In childhood, crosslinks excretion exceeded normal adult values by about fivefold and declined during puberty. In the age range of 13–18 years, gender-related differences in Pyr and DPyr levels were observed, presumably resulting from the earlier onset of puberty in girls. Urinary levels of Pyr and DPyr were highly correlated both in males and females. Pyr/DPyr ratio was significantly higher in adolescents than children, suggesting enhanced release of Pyr from extraosseous sources. In both genders, neither age nor anthropometric variables showed a linear effect on crosslinks excretion. The range of within-subject, short-term variability in urinary Pyr and DPyr was relatively high (CV: 6%–21%), indicating that single measurements of crosslinks excretion may not adequately reflect bone resorption rates in children. Pyr and DPyr levels were significantly lower in GH-deficient patients and normalized during human growth hormone (hGH) therapy. Significant correlations between growth velocity (GV) and crosslinks levels were found, but individual prediction of GV increment during hGH treatment may be inaccurate. Pyr/DPyr ratio was not related to GV. It is concluded that measurement of urinary Pyr and DPyr excretion in children may be a valuable tool to assess bone resorption rates in population-based studies. In individual patients, however, only qualitative evaluation of disease severity and response to treatment seems justified.     

Secretogranin I (chromogranin B) mRNA accumulation is hormonally regulated in GH3B6 rat pituitary tumor cells

Secretogranin I (SgI; chromogranin B) belongs to a class of acidic tyrosine-sulfated secretory proteins believed to play a role in the secretory process of endocrine cells. Our aim here was to compare the levels of SgI mRNA to that of prolactin (PRL) and growth hormone (GH), using rat pituitary cell lines. As far as the constitutive expression is concerned, we found a positive correlation between SgI mRNA and PRL mRNA levels. However, the neuropeptide TRH (50 nM) inhibited the accumulation of SgI mRNA in GH3B6 cells whereas, as expected, it induced a rapid and sustained increase in PRL mRNA accumulation. By contrast, 17β-estradiol (1 nM) stimulated the accumulation of both SgI and PRL mRNAs, with the same EC₅₀ (18–59 pM). Reciprocally, treatment with dexamethasone (100 nM) reduced the level of SgI and PRL mRNAs to 23% and 29% of control, respectively, but led to a 2.1-fold increase in the GH mRNA level. Altogether, the present work shows that SgI gene expression is subject to multiple hormonal regulations and occasionally parallels the regulation of the PRL gene but never that of the GH gene, under the conditions tested.     

Interactions between growth hormone and dexamethasone in skeletal growth and bone structure of the young mouse

Summary The present study investigated the interactions of growth hormone (GH) and glucocorticoid on skeletal growth and bone structure in young mice. The purpose of this study was to examine the possible prevention by GH of the damage inflicted by dexamethasone (Dex) at sites of skeletal growth and ossification. Dex (1 mg/kg) with or without rat GH (rGH) or bovine GH (bGH), 1 mg/kg, was given for 4 weeks, from age 3–7 weeks, to female ICR mice. Tibiae, humerus, and vertebrae were analyzed morphometrically and biochemically. Growth, as determined by the mouse weight, tibial length, and humerus protein content was found to be compromised by dexamethasone. This was prevented by rGH or bGH. The epiphyseal growth plate width, trabecular bone volume, cortical bone width, mineral bone content, and alkaline and acid phosphatase activity were decreased by dexamethasone. These were prevented by rGH or by bGH. The findings of the present study suggest that in the mouse, GH can decrease or even avoid some of the pathological features in growing bones inflicted by high-dose glucocorticoid treatment.