中国汉族乡村成年人的身高与体质量的地理性分布

目前尚未见大样本的中国乡村汉族人随纬度、经度增长,身高、体质量值的变化规律的报道。为此,2009～2013年测量了16501例汉族人(共36个调查地区)乡村成人的身高、体质量等13项指标值,并计算了3项指数。研究不同纬度、经度地区汉族乡村成人的身高、体质量值变化规律以及这种规律形成的原因。研究发现,汉族人的身高、体质量与纬度、经度均呈正相关。随纬度增加,男性和女性的躯干、下肢的高度值均增大是身高与纬度呈正相关的原因。随纬度增加,男性身高的增加、躯干的增粗共同促进体质量与纬度呈正相关,女性身高、躯干围度、四肢围度、背部皮下脂肪厚度值的增大是体质量与纬度呈正相关的原因。男性随经度增加,身高增大,躯干部的增粗是导致体质量与经度相关的原因。而四肢和躯干的皮下脂肪、四肢的围度并不随经度的增加而线性增大。随经度增加,女性的身高、臀围呈线性增大,这是导致女性体质量与经度相关的主要原因。遗传、环境、经济发展水平的差异是导致身高、体质量与纬度、经度呈正相关的因素。     

Immunological characterization of thioltransferase from pig liver

Polyclonal antibodies against pig liver thioltransferase were raised in a New Zealand rabbit. These antibodies completely neutralized the thioltransferase activity of the homogeneous enzyme and that in the crude cytosolic homogenate at an equivalent titer. The antibodies also cross-reacted equally with calf thymus glutaredoxin and calf liver thioltransferase, but not with Escherichia coli thioredoxin, suggesting that thioltransferase and glutaredoxin from the same species are identical. Immunoblotting analysis of the cytosolic proteins from 14 different pig tissues revealed that most pig tissues contain a 12-kDa protein which reacts with these antibodies. This protein is found in greater abundance in stomach, small intestine, liver, skeletal muscle, kidney, heart, lung, and cerebral cortex, whereas retina, cerebellum, spleen, pancreas, and thymus have low levels of the protein. No reactive protein was detected in the lens. The tissue distribution of the protein was also determined by assay of the enzyme activity and was generally in good agreement with that obtained from the immunoblotting survey. Pig liver thioltransferase was cleaved by trypsin, chymotrypsin, Staphylococcus aureus V8 protease, and cyanogen bromide. The selected peptides purified by reversed phase high performance liquid chromatography or ion exchange fast protein liquid chromatography were subjected to reaction with the polyclonal antibodies against pig liver thioltransferase. Four antigenically reactive fragments were detected by dot-blotting analysis. These peptides are located in the first 30-amino acid residues from the NH2 terminus and the sequence from amino acid residues 39-67, indicating that the active site of the enzyme, Cys22 and Cys25, is located on one of the antigenic determinant domains.     

High-level expression in Escherichia coli of a chemically synthesized gene for [Leu-28]echistatin

A gene (Ecs) encoding a platelet aggregation inhibitor, echistatin (Ecs), has been chemically synthesized. Met at position 28 of the native protein was replaced by Leu in the recombinant Ecs. To express this synthetic gene in Escherichia coli, an expression vector, pJC264, was constructed by inserting portions of the E. coli cheB and cheY gene complex into the plasmid pUC13. High-level expression of the synthetic [Leu-28]Ecs was achieved by its fusion with the E. coli cheY gene in the expression vector. Recombinant [Leu-28]Ecs was liberated from the fusion protein by CNBr cleavage at the Met inserted between the CheY protein and [Leu-28]Ecs. The recombinant [Leu-28]Ecs was purified to homogeneity by reverse-phase high-performance liquid chromatography. The refolded [Leu-28]Ecs was identical to native Ecs in inhibiting platelet aggregation, suggesting that Met at position 28 is not essential for the biological activity of this platelet aggregation inhibitor.     

距离分析方法与杂种优势

对于75个小麦品种两年的试验结果,采用不同方法进行距离比较分析。结果表明:用表型平均值相关阵经主成分转换,计算品种间欧氏距离,再用类平均法聚类,似乎是适宜的距离分析方法。D~2值在年份间较稳定,不同年份的D~2估值,可用于预测杂种优势。根据13个性状估算的品种间距离(D~2)与株粒重杂种优势(H)之间呈曲线关系,其理论方程是:Y=-3.65 6.665X--0.1288X~2。根据该方程推算:D~2=25.87时,H出现最大值。     

北京地区全新世植被和气候变化研究进展

该文综述了北京地区全新世以来植被演替和气候变化的相关研究资料,这些资料反映了当前阶段对该地区该时段植被与气候环境格局特征的认识。北京地区全新世早期(约12 000–8 000 cal a B.P.)植被为森林草地和/或针叶树占主导的针阔混交林,森林中阔叶树类群逐渐增多,指示了气候由寒冷干燥转为温暖湿润;全新世中期(约8 000–2 000 cal a B.P.前后)植被为暖温带针阔混交林,指示暖湿气候;全新世晚期(约2 000 cal a B.P.以来)转为森林草地和/或针叶树占主导的针阔混交林,气候转向凉干。植被演替反映的湿润度变化与季风区其它地区变化趋势一致。值得注意的是,前人研究揭示北京地区山区与平原中植被类型和类群组成已经出现空间分异。今后如能深入开展定量古气候重建研究,有可能精确描述其气候变化的过程,增进中国不同地理单元同时期气候变化的对比。     

Enhancement of acid-sensing ion channel activity by metabotropic P2Y UTP receptors in primary sensory neurons

Peripheral purinergic signaling plays an important role in nociception. Increasing evidence suggests that metabotropic P2Y receptors are also involved, but little is known about the underlying mechanism. Herein, we report that selective P2Y receptor agonist uridine 5′-triphosphate (UTP) can exert an enhancing effect on the functional activity of acid-sensing ion channels (ASICs), key sensors for extracellular protons, in rat dorsal root ganglia (DRG) neurons. First, UTP dose-dependently increased the amplitude of ASIC currents. UTP also shifted the concentration–response curve for proton upwards, with a 56.6?±?6.4 % increase of the maximal current response to proton. Second, UTP potentiation of proton-gated currents can be mimicked by adenosine 5′-triphosphate (ATP), but not by P2Y1 receptor agonist ADP. Potentiation of UTP was blocked by P2Y receptor antagonist suramin and by inhibition of intracellular G protein, phospholipase C (PLC), protein kinase C (PKC), or protein interacting with C-kinase 1 (PICK1) signaling. Third, UTP altered acidosis-evoked membrane excitability of DRG neurons and caused a significant increase in the amplitude of the depolarization and the number of spikes induced by acid stimuli. Finally, UTP dose-dependently exacerbated nociceptive responses to injection of acetic acid in rats. These results suggest that UTP enhanced ASIC-mediated currents and nociceptive responses, which reveal a novel peripheral mechanism underlying UTP-sensitive P2Y₂ receptor involvement in hyperalgesia by sensitizing ASICs in primary sensory neurons.     

Left ventricular diastolic dysfunction in type 2 diabetes patients: a novel 2D strain analysis based on cardiac magnetic resonance imaging

Objective: This study was to develop a strain analysis method to evaluate the left ventricular (LV) functions in type 2 diabetic patients with an asymptomatic LV diastolic dysfunction. Methods: Two groups (10 asymptomatic type 2 diabetic subjects and 10 control ones) were considered. All of the subjects had normal ejection fraction values but impaired diastolic functions assessed by the transmitral blood flow velocity. For each subject, based on cardiac MRI, global indexes including LV volume, LV myocardial mass, cardiac index (CI), and transmitral peak velocity, were measured, and regional indexes (i.e., LV deformation, strain and strain rate) were calculated through an image-registration technology. Results: Most of the global indexes did not differentiate between the two groups, except for the CI, LV myocardial mass and transmitral peak velocity. While for the regional indexes, the global LV diastolic dysfunction of the diabetic indicated an increased strain (0.08?±?0.044 vs. ?0.031?±?0.077, p?=?0.001) and a reduced strain rate (1.834?±?0.909 vs. 3.791?±?2.394, p?=?0.033) compared to the controls, moreover, the local LV diastolic dysfunction reflected by the strain and strain rate varied, and the degree of dysfunction gradually decreased from the basal level to the apical level. Conclusions: The results showed that the strain and strain rates are effective to capture the subtle alterations of the LV functions, and the proposed method can be used to estimate the LV myocardial function based on cardiac MRI.     

A Method to Quantify Cell-Free Fetal DNA Fraction in Maternal Plasma Using Next Generation Sequencing: Its Application in Non-Invasive Prenatal Chromosomal Aneuploidy Detection

Objective

The fraction of circulating cell-free fetal (cff) DNA in maternal plasma is a critical parameter for aneuploidy screening with non-invasive prenatal testing, especially for those samples located in equivocal zones. We developed an approach to quantify cff DNA fractions directly with sequencing data, and increased cff DNAs by optimizing library construction procedure.

Methods

Artificial DNA mixture samples (360), with known cff DNA fractions, were used to develop a method to determine cff DNA fraction through calculating the proportion of Y chromosomal unique reads, with sequencing data generated by Ion Proton. To validate our method, we investigated cff DNA fractions of 2,063 pregnant women with fetuses who were diagnosed as high risk of fetal defects. The z-score was calculated to determine aneuploidies for chromosomes 21, 18 and 13. The relationships between z-score and parameters of pregnancies were also analyzed. To improve cff DNA fractions in our samples, two groups were established as follows: in group A, the large-size DNA fragments were removed, and in group B these were retained, during library construction.

Results

A method to determine cff DNA fractions was successfully developed using 360 artificial mixture samples in which cff DNA fractions were known. A strong positive correlation was found between z-score and fetal DNA fraction in the artificial mixture samples of trisomy 21, 18 and 13, as well as in clinical maternal plasma samples. There was a positive correlation between gestational age and the cff DNA fraction in the clinical samples, but no correlation for maternal age. Moreover, increased fetal DNA fractions were found in group A compared to group B.

Conclusion

A relatively accurate method was developed to determine the cff DNA fraction in maternal plasma. By optimizing, we can improve cff DNA fractions in sequencing samples, which may contribute to improvements in detection rate and reliability.     

Immunoassay of <Emphasis Type="Italic">S</Emphasis>-adenosylmethionine and <Emphasis Type="Italic">S</Emphasis>-adenosylhomocysteine: the methylation index as a biomarker for disease and health status

Background

S-Adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) are relevant to a variety of diseases. Previous reports that quantified SAM and SAH were based on HPLC or LC–MS/MS. No antibody against SAM has been generated, and the antibody against SAH cannot be used with blood samples. Immunoassays have not been used to measure SAM and SAH. In this study, ELISA was used to measure blood SAM and SAH levels.

Results

Specific antibodies against SAM were produced for the first time using a stable analog as the antigen. The monoclonal antibodies against SAM and SAH were characterized. No cross-reactivity was detected for the analyzed analogs. For the anti-SAM antibodies, the ELISA sensitivity was ~2 nM, and the affinity was 7.29 × 10¹⁰ L/mol. For the anti-SAH antibodies, the sensitivity was ~15 nM, and the affinity was 2.79 × 10⁸ L/mol. Using high-quality antibodies against SAM and SAH, immunoassays for the detection of SAM and SAH levels in blood and tissue samples were developed. Clinical investigations using immunoassays to measure SAM, SAH and the methylation index (MI) in normal and diseased samples indicated that (1) the SAM level is age and gender dependent; (2) the SAM level is associated with the severity of liver diseases, inflammatory reactions and other diseases; and (3) the methylation index (MI) is significantly reduced in many diseases and may serve as a screening biomarker to identify potentially unfavorable health conditions.

Conclusion

It is possible to generate antibodies against active small biomolecules with weak immunogenicity, such as SAM and SAH, using traditional hybridoma technology. The antigens and antibodies described here will contribute to the development of immunoassays to measure SAM, SAH and related molecules. These assays enable the MI to be measured specifically, accurately, easily and quickly without costly equipment. This preliminary study indicates that the MI could be an effective indicator of general health, except under conditions that may alter the value of the MI, such as special diets and medications.