Artificial Feeding of Neonatal Rats

Newborn rats, fed either cow's milk or rat's milk by tube, developed a "bloat" and the time required for emptying the stomach increased. When these animals were allowed to suckle on nonlactating foster mothers, no evidence of this syndrome was observed. Based on these observations, a technique was developed for the artificial feeding of newborn rats. When the diet was rat's milk, growth equivalent to that of animals fed solely by lactating females was obtained. A diet of cow's milk did not support adequate growth.     

牛生长激素催乳作用研究进展

牛生长激素（ｂＧＨ）是由脑垂体产生的一种不含糖的单链多肽,含１９０或１９１个氨基酸序列。其主要作用包括：增加脂解作用、致糖尿作用,促进骨生成、糖异生、乳腺发育及维持泌乳。近年来ｂＧＨ再次成为研究热点,一方面是因为ｂＧＨ能显著提高奶畜奶产量,并改善家畜的增重速度、胴体品质及饲料利用率;另一方面是基因工程的迅速发展为大量生产蛋白质激素开辟了广阔前景,使ｂＧＨ的研究有了药源保证。近年来的研究工作主要集中     

Genetic engineering of livestock

Genetic engineering of livestock is expected to have a major effect on the agricultural industry. However, accurate assessment of the consequences of transgene expression is impossible without multigenerational studies. A systematic study of the beneficial and adverse consequences of long-term elevations in the plasma levels of bovine growth hormone (bGH) was conducted on two lines of transgenic pigs. Two successive generations of pigs expressing the bGH gene showed significant improvements in both daily weight gain and feed efficiency and exhibited changes in carcass composition that included a marked reduction in subcutaneous fat. However, long-term elevation of bGH was generally detrimental to health: the pigs had a high incidence of gastric ulcers, arthritis, cardiomegaly, dermatitis, and renal disease. The ability to produce pigs exhibiting only the beneficial, growth-promoting effects of growth hormone by a transgenic approach may require better control of transgene expression, a different genetic background, or a modified husbandry regimen.     

重组牛生长激素对山羊卵泡卵母细胞体外成熟的影响

将３０７枚Ａ、Ｂ级卵丘－卵母细胞复合体（ＣＯＣ）分别培养于：改良ＴＣＭ１９９＋ＦＳＨ（１０μｇ／ｍｌ）＋ＬＨ（２０μｇ／ｍｌ）＋２０％ＮＣＳ（Ａ液）、Ａ液＋重组牛生长激素（ｒｂＧＨ）１５ｎｇ／ｍｌ、改良ＴＣＭ１９９＋ｈＣＧ（２０μｇ／ｍｌ）＋ｒｂＧＨ＋２０％ＮＣＳ三种培养基中，获得５３１％、６７９％和６３５％的成熟率。结果表明，ｒｂＧＨ对山羊卵泡卵母细胞的体外成熟是有益的。     

Agricultural research and farm structural change: Bovine growth hormone and beyond

Emerging bovine somatotropin (or “bovine growth hormone” [bGH]) technology has become highly controversial even though the technology is one to two years from commercial introduction. The bGH controversy is discussed and placed in the context of the evolution of the American public agricultural research system and farm structural change over the past 15 years. It is argued that while many observers tend to overestimate the degree to which bGH will be representative of other biotechnologies applied to agriculture, the bGH case may well reflect a more general pattern of the changing clientele relations of the land-grant system and of the changing character of technology developed within the public agricultural research system. In particular, these new clientele and technical relations may portend a new era in which farmers begin to scrutinize the land-grant research portfolio, which might in turn lead to diminished political support by state-level farmers' groups for agricultural research appropriations.     

氰戊菊酯的毒性研究

氰戊菊酯是第一个非三碳环骨架的拟除虫菊酯。在本研究中,对大、小鼠的经口LD_(50)分别为215mg/kg和93.33mg/kg,具中等毒性。其中毒症状与α-CN拟除虫菊酯的Ⅱ型(CS型)症状(不安、流涎、抽搐和后肢姿态异常)相符合。对大鼠的蓄积系数为6.8,无明显的蓄积毒性。其5％的水乳剂对眼和皮肤不呈现通常的刺激征象(红肿等),但对皮肤可出现一种感觉神经过敏的刺激反应。对小鼠骨髓细胞微核试验呈阴性结果。     

牛生长激素基因外显子5序列变异及其分子进化特征

通过双向直接测序法测定中国5个牛种生长激素(GH)基因外显子5序列,并且在分析序列变异的基础上探讨GH基因外显子5序列的分子进化特征.序列分析表明,5个牛种GH基因外显子5的遗传变异水平较低,平均核苷酸变异率约为3.48%,而且绝大多数位点的核苷酸替换是同义突变,仅发现1个错义突变位点;从GH基因外显子5序列单倍型构建的分子进化树来看,水牛与普通牛、瘤牛、牦牛及大额牛的分化相对比较明显,其他4个牛种之间并无明显分化,还享有共同的祖先序列.研究结果也说明牛GH基因外显子5在进化过程中由于功能的约束表现相当保守,进化速率缓慢.     

Physiological role of silent receptors of atrial natriuretic factor

A ring-deleted analog of atrial natriuretic factor--des[Gln18, Ser19, Gly20, Leu21, Gly22] ANF4-23-NH2 (C-ANF4-23)--binds with high affinity to approximately 99% of ANF receptors in the isolated perfused rat kidney. In this preparation, C-ANF4-23 is devoid of detectable renal effects and does not antagonize any of the known renal hemodynamic and natriuretic actions of biologically active ANF1-28. In contrast, both C-ANF4-23 and ANF1-28 increase sodium excretion and decrease blood pressure in intact anesthetized rats. This apparent contradiction is resolved by the finding that the ring-deleted analog markedly increases plasma levels of endogenous immunoreactive ANF in the rat. The results show that the majority of the renal receptors of ANF are biologically silent. This new class of receptors may serve as specific peripheral storage-clearance binding sites, acting as a hormonal buffer system to modulate plasma levels of ANF.     

水牛初乳粉对新生仔猪肠道黏膜和肝脏IGF-I及IGF-IR基因表达的影响

水牛初乳富含免疫球蛋白和生长因子等活性物质,对新生哺乳动物具有良好的营养作用.选用新生仔猪为试验对象,分别饲喂水牛初乳粉（SCR组）、水牛常乳粉（SC组）、葡萄糖盐水（PY组）,并以0日龄新生仔猪作为对照（XD组）.研究水牛初乳粉对新生仔猪肠道粘膜及肝脏IGF-I、IGF-IR表达量的影响.结果表明,水牛初乳粉使新生仔猪在最初发育的3d内,肠道粘膜和肝脏中IGF-I基因表达量大幅度增加,IGF-I mRNA/β-actin比值高于XD组且P＜0.01;通过IGF-IR基因表达的研究发现,水牛初乳粉能增加肠粘膜中IGF-IR的表达量,但增幅小于IGF-I表达量;在肝脏中,水牛初乳粉使IGF-IR基因表达量略有降低,但与其它两个试验组相比,降低值最小,PY组次之,SC组降低值最大.水牛初乳能显著促进新生仔猪肠道和肝脏IGF-I基因表达,而对IGF-IR基因表达的影响表现为肠粘膜中表达量增加,脏脏中表达量降低.     

中国荷斯坦牛乳成分数量性状表型参数分析

根据工农联盟奶牛一场（１９９６～１９９８年）９３４头中国荷斯坦牛的乳脂率、乳蛋白率和干物质含量的测定,按不同胎次统计分析获得如下牛乳成分表型参数：乳脂率３．８１±０．３９２％,乳蛋白率３．１０±０．２３６％,干物质含量１２．２６±０．６７０％,其中各胎次乳成分为：第１胎最高,乳脂率３．９６％,乳蛋白率３．１４％,干物质含量１２．６３％,以后随胎次增长有下降趋势。     

Effects of tyrosine administration on serum biopterin in normal controls and patients with Parkinson's disease

After administration of tyrosine, total concentration of biopterin, the cofactor for tyrosine hydroxylase, was increased in the striatum, adrenal glands, and serum of rats, and in the serum of humans. Serum biopterin is lower in patients with Parkinson's disease than in normal controls. After oral administration of tyrosine, the increase in serum biopterin concentration was smaller in patients with Parkinson's disease (less than twofold) than in healthy controls (three-to sevenfold). These results suggest that tyrosine may have a regulatory role in biopterin biosynthesis and that patients with Parkinson's disease may have some abnormality in the regulation of biopterin biosynthesis.     

At least three human type alpha interferons: structure of alpha 2

The sequence of a human leukocyte-derived complementary DNA (cDNA), Hif-2h, which directs the formation in Escherichia coli of a polypeptide, IFN-alpha 1, with interferon (IFN) activity has been described. A second IFN cDNA, Hif-SN206, which also elicits synthesis of a biologically active IFN, IFN-alpha 2, is described in this article. Whereas IFN-alpha 2 is twice as active on human as on bovine cells, IFN-alpha 1 is 10 to 20 times more active on bovine than on human cells. As deduced from the cDNA's, the messenger RNA's for the two IFN's differ in length and in 20 percent of the nucleotides; the mature IFN polypeptides differ in 17 percent of the amino acids. Both IFN-alpha 1 and IFN-alpha 2 differ from the lymphoblastoid IFN described by others. Therefore, at least three different IFN-alpha genes are expressed in man; studies on genomic DNA reveal the presence of at least eight IFN-related genes.     

Radioreceptor assay of human chorionic gonadotropin: detection of early pregnancy

A rapid, sensitive, and specific radioreceptor assay for the determination of human chorionic gonadotropin and luteinizing hormone in plasma is described. Plasma membranes of bovine corpora lutea of early pregnancy, which bind biologically active labeled human chorionic gonadotropin, have been used as receptor. Pregnancy could be detected by assaying the gonadotropin in plasma samples obtained from day 6 to 8 after conception.     

性激素类物质在农产品中的残留及检测

近年来由于过量使用外源性激素作为动物饲料添加剂和植物生长调节剂,导致部分农产品受到性激素类物质污染并在农产品中残留,此外牛奶等乳制品中雌激素水平也有显著上升.这些性激素残留通过食物链在人体内积累,可诱发癌变,对生殖与神经等系统带来影响,还造成一定的环境问题.目前农产品中的性激素残留可用高效液相色谱法、酶联免疫吸附法等方法进行检测.     

The case against bGH

In the voluminous literature on the subject of bGH we have yet to find an attempt to frame the issue in specifically moral terms or to address systematically its ethical implications. I argue that there are two moral objections to the technology: its treatment of animals, and its dislocating effects on farmers. There are agricultural biotechnologies that deserve funding and support. bGH is not one of them.     

牛乳房炎发病原因探讨

牛乳房炎是给乳牛养殖业带来重大经济损失的疾病之一。伴随着乳量、乳质的下降,异常乳的废弃以及治疗费用的增加,造成经营者意志减退。如果检验不严,使抗菌素乳及带菌乳混入市场,势必给广大消费者的健康带来威胁。因此对乳房炎发病原因进行探讨,对乳房炎的防治以及降低发病率具有重要意义。     

干苹果渣对奶牛产奶量及乳成分的影响

为研究干苹果渣对奶牛产奶量及乳成分的影响,选择27头荷斯坦泌乳奶牛进行试验。将27头荷斯坦奶牛分为A、B、对照3组,在A组的饲粮中添加干苹果渣3 kg/(头.d),B组添加干苹果渣6 kg/(头.d)。结果表明,与不添加干苹果渣的对照组相比,A组、B组奶牛产奶量每头分别提高3.13、2.21 kg/(头.d),增产效果显著(P<0.05)。两试验组乳糖含量均显著高于对照组(P<0.05),其他乳成分差异不显著,提示干苹果渣有提高奶牛产奶量及改善乳品质的作用,且以添加3 kg/(头.d)干苹果渣较为适宜。     

乳铁蛋白牛初乳颗粒的毒理安全性研究

[目的]为判定聪贝优牌乳铁蛋白牛初乳颗粒对人体健康是否产生危害,进行了聪贝优牌乳铁蛋白牛初乳颗粒的安全性毒理学评价。[方法]采用急性毒性试验、Ames试验、小鼠骨髓微核实验、微小鼠精子畸形试验和30 d喂养试验对聪贝优牌乳铁蛋白牛初乳颗粒急性毒性、致突变性以及亚慢性毒性进行了研究。[结果]聪贝优牌乳铁蛋白牛初乳颗粒小鼠急性毒性试验LD50大于20.0 g/(kg.bw),属实际无毒;对基因、体细胞与生殖细胞无明显致突作用;受试物分别按1.00、2.00、4.00 g/(kg.bw)的剂量喂养大鼠30 d,结果表明动物未出现异常。[结论]根据试验结果,可判定聪贝优牌乳铁蛋白牛初乳颗粒为安全性食品。     

酒精阳性乳症牛血液细胞变化的研究

本文对酒精阳性乳症牛血液细胞及某些血液成分进行了检测。结果表明:白细胞总数、红细胞数、血红蛋白含量增加,嗜酸性粒细胞百分比显著增多。特别是后者升高为应激反应的特征。     

Expression of recombinant human butyrylcholinesterase in the milk of transgenic mice

Butyrylcholinesterase (BCHE) is a natural bioscavenger that protects humans against organophosphate toxicity. Due to the limited yield of human BCHE (hBCHE) when purifying from human plasma, it is necessary to find an alternative method to produce this protein. One potential method is to produce transgenic livestock that make modified milk containing high concentration of hBCHE. In this study, we cloned the hBCHEgene into a human lactoferrin (hLF) bacterial artificial chromosome (BAC) construct to make a hLF-hBCHE BAC construct. Subsequently, we injected the BAC construct into pronuclei of mouse fertilized embryos and generated transgenic mice. Expression analysis showed that recombinant hBCHE (rhBCHE) was expressed efficiently in the mammary gland of the transgenic mice and the concentration of rhBCHE in the milk of individual mice ranged from 76±12 to 159±28 mg·L^-1. Protein function tests showed that rhBCHE has the same enzymatic activity as the native hBCHE. Our results pave the way for making transgenic livestock to produce large quantities of rhBCHE.