发情周期和妊娠早期牦牛乳汁中孕酮含量的变化

本试验采用放射免疫分析(RIA)方法对牦牛发情周期和妊娠早期乳汁中孕酮的含量进行了测定。在发情周期的1d和3d,礼汁中孕酮含量分别为0.4±0.08ng/ml和0.55±0.12ng/ml。而后开始显著升高,15d时达到峰值(21.37±6.58ng/ml)。随后出现下降,19,21d时降至发情之初的水平,分别为0.93±0.16ng/ml和0.42±0.07ng/ml。妊娠早期牦牛从发情配种开始到怀孕14d内乳汁中孕酮水平与发情周期牦牛乳汁中孕酮水平基本一致(P>0.05)。在怀孕的15d出现一短暂而明显的下降(15.47±2.68ng/ml)。而后含量继续升高。妊娠的19d,21d时,乳汁中孕酮含量分别为32.32±9.73ng/ml和36.45±7.56ng/ml,极显著的高于发情周期牛(P<0.001)随后妊娠早期的60d内呈持续上升的趋势。     

菜籽粕对公母仔鸡甲状腺功能影响的比较研究

用放射免疫分析法研究了菜籽粕对公母仔鸡血清中三碘甲腺原氨酸和甲状腺素浓度影响的性别差异,考察了甲状腺肿效应与血清中甲状腺激素浓度变化关系。结果表明:①12%菜籽粕使仔母鸡血清三碘甲腺原氨酸浓度均值极显著降低(P<0.01),尤其在饲喂菜籽粕4周以内影响更大;而对仔公鸡没有显著影响(P>0.05);②12%菜籽粕对仔鸡血清甲状腺素浓度无显著影响(P>0.05);但前期血清甲状腺素浓度略有增加,后期略为下降;③12%菜籽粕导致8周龄仔鸡甲状腺极显著增大(P<0.01),而对肝重、肾重和脾重则无显著影响(P>0.05)。因此,菜籽粕对仔鸡血清甲状腺激素浓度的影响,存在性别差异,雌性比雄性反应敏感。在公母仔鸡饲粮中,菜籽粕用量应有所不同。     

Application of a radioimmunoassay for detection of the major internal antigen (p24) of bovine leukemia virus from cultured lymphocytes of cattle

A sensitive and specific radioimmunoassay for the major internal antigen of bovine leukemia virus has been applied to detecting this protein in cultured lymphocytes of infected cattle. The specificity inherent in this assay offers obvious advantages over a previously described syncytium induction assay for infectious bovine leukemia virus, because false positive reactions due to other viruses such as bovine syncytial virus are avoided. Investigations of various culture conditions indicated that maximal amounts of antigen had been produced after incubation for 72 hr at 37°C. Lymphocyte concentrations of 10⁶?5×10⁷ cells/ml gave satisfactory results. Tests of cultured lymphocytes from bovine leukemia virus infected or bovine leukemia virus-free cattle indicated a comparable sensitivity between the radioimmunoassay and syncytium induction assay in the detection of bovine leukemia virus infections.     

Preliminary study on relationship between renin-angiotensin-aldosterone system and hypertension in coal miners

AIM: To study the relationship between renin-angiotensin-aldosterone system and hypertension in coal miners. METHODS: The coal miners received questionnaire investigation and their blood pressure, height and weight were measured, plasma renin activity (PRA), plasma angiotensin Ⅱ(Ang Ⅱ) and aldosterone (ALD) were tested by means of radio immunoassay in coal miners with hypertension and nor-hypertension. RESULTS: It was found that levels of PRA, Ang Ⅱ and ALD were significantly higher in hypertensive group than in nor-hypertensive group (all P<0.01), average blood pressure had positive correlation with levels of PRA, Ang Ⅱ and ALD in all miners (r=0.371, r=0.412 and r=0.352). In coal miners with hypertension, levels of PRA, Ang Ⅱand ALD were significantly higher in underpit operation group than in ground operation group (all P<0.01), and install-repair group's were highest in underpit operation group; Levels of PRA, Ang Ⅱand ALD were significantly higher in high-salt diet group than in normal diet group (all P<0.01), but there was no significant change in age, length of service, family history, body mass index, smoking and alcoholism on levels of PRA, Ang Ⅱ and ALD. CONCLUSION: The renin-angiotensin-aldosterone system may potentially mediate underpit operation-and salt-induced hypertension pathogenesis in coal miners.     

Endogenous cytokinin levels of table grape vines during spring budburst as influenced by hydrogen cyanamide application and pruning

Cytokinins play an important role in budburst, flowering and fruit set in table grapes. Rest-breaking treatments with hydrogen cyanamide and pruning practices modify budburst and reproductive development in table grapes, especially in regions with low and often inadequate winter chilling. The effect of these treatments on the xylem sap and bud Zeatin riboside (ZR) content was determined during late winter and budburst in ‘Sultanina’, ‘Sunred Seedless’, and ‘Alphonse Lavalleé’ canes in a total of nine trials conducted between 1997 and 2001. Bud ZR levels of hydrogen cyanamide treated ‘Sultanina’ canes showed an earlier and increased cytokinin peak, in particular in the distal buds. Large ZR peaks before budburst and noticeable differences between distal and proximal buds were absent on non-sprayed canes. The xylary ZR content of long pruned ‘Sultanina’, ‘Sunred Seedless’, and ‘Alphonse Lavaleé’ canes showed a significantly higher and earlier cytokinin peak than in short pruned spurs. By contrast, the bud ZR content tended to be higher in spurs than canes. Pruning and rest-breaking treatments enhanced budburst and increased endogenous cytokinins in these experiments. Long pruning in ‘Sultanina’ and ‘Sunred Seedless’ (both parthenocarpic) is necessary for acceptable fruit set and yields. Possibly, in longer canes more cytokinin is available for reproductive development. ‘Alphonse Lavaleé’ (seeded) is sufficiently fruitful and produces adequate yields following spur pruning.     

The relations among PAMP,ADM and AngⅡ on vascular tissue

AIM: To elucidate the relations among proadrenomedullin N terminal 20 peptide(PAMP), adrenomedullin(ADM)and angiotensin(Ang).METHODS: Tissue slices of rat aorta were incubated as follows:(I) increasing concentrations of AngⅡ(10^-9, 10^-8, 10^-7 mol/L); increasing concentrations of PAMP(10^-9,10^-8,10^-7mol/L).The tissue and incubation concentrations of PAMP,ADM and AngⅡ were measured by the radioimmunoassay (RIA).RESULTS: The tissue and incubation concentrations of PAMP and ADM were concentration-dependently increased by AngⅡ,but the tissue and incubation concentrations of AngⅡ can not effected by PAMP.CONCLUSION: AngⅡ markedly stimulate the release of ADM and PAMP.It may be one of the factors which regulate the synthesis and release of ADM and PAMP.The regulation may play an important role in homeostasis regulation of cardiovascular system.     

葡萄果实脱落酸含量的放射免疫测定

以红富士葡萄果实为试材,以水为脱落酸的浸提剂,利用ＡＢＡ单克隆抗体ＭＡＣ６２,建立一套适合葡萄果实微量样品,且样品浸提液不需进一步纯化就可直接用于ＡＢＡ测定的放射免疫测定技术。把ＲＩＡ法与高效液相色谱法进行了比较,ＲＩＡ以其简便快捷,灵敏度高,专一性强,测得结果重复性好为显著特点,显示出比ＨＰＬＣ更大的优越性。     

胚胎及新生期蛋鸡和肉鸡垂体生长激素基因表达的比较研究

本文采用Northern杂交分析法研究了14胚龄、18胚龄、1日龄、5日龄及10日龄肉鸡和蛋鸡垂体生长激素的基因表达，同时采用放射免疫分析法（RIA）测定了垂体内生长激素的含量。结果表明：14胚龄时在肉鸡和蛋鸡垂体总RNA中均未出生长激素mRNA(GH mRNA)。从18胚龄开始可检测出一条0.8kb的GHmRNA，并且垂体GHmRNA水平的发育性变化在品种间呈现不同的规律：蛋鸡从18胚龄到10日龄垂体GHmRNA水平不断升高，日龄间差异显著（P＜0.05）。肉鸡从18胚龄到出壳1日龄，GHmRNA水平有较大幅度的升高，但从1日龄至10日龄维持在1日龄时的水平。18胚龄肉鸡垂体GH mRNA水平显著高于蛋鸡（P＜0.05），并在1日龄和5日龄均维持在较高水平，与生长速度呈正相关；而10日龄时垂体HGmRNA水平的品种差异发生逆转，蛋鸡GHmRNA水平反而高于肉鸡。垂体HG含量的发育性变化趋势与垂体HGmRNA水平相一致，10日龄时蛋鸡垂体GH含量显著高于肉鸡（P＜0.05），与生长速度呈相反的趋。     

Radioimmunoassay of milk progesterone as a tool for fertility control in smallholder dairy farms

This study focused on the use of radioimmunoassay of progesterone in milk for the diagnosis of post-partum ovarian cyclicity and accurate detection of oestrus and non-pregnancy in cows in the artificial insemination (AI) programme in Bangladesh. In Investigation 1, milk samples were collected on day 0 (day of AI), day 9–13 and day 21–24 from 444 milking cows of various breeds presented for the first post-partum insemination by 413 farmers living at 182 villages/regions in Mymensingh District from 6 AI centres and sub-centres. Each cow was then examined three times after each AI until it stopped returning to oestrus. Sixty to 90 days after the last AI, the cows were examined per rectum to confirm the pregnancy. Milk progesterone data on day 21–24 contributed to a clear diagnosis with respect to non-pregnancy in 100% cows, indicating a possible use of this progesterone assay for identifying non-pregnant cows in AI programmes. In Investigation 2, milk progesterone was monitored two times in a month with a 10-day interval in 88 cows. The samples were taken between 10 days after calving and the first detected oestrus, followed by two more samples 10 days apart. The proportion of cows accurately detected in oestrus was 30%. Another 30% were stated to be in oestrus when they were not (false positive) and 40% were not detected when they were in oestrus (false negative). The mean intervals between calving and oestrus and between calving luteal activity were 40 to 362 days (median = 120, n = 82) and 34 to 398 (median = 111, n = 64) days, respectively. The body condition scores at calving and at the initiation of luteal activity influenced the interval between calving and luteal activity (p < 0.05). Cows suckled twice daily initiated luteal activity earlier than their counterparts suckled several times daily (p < 0.05). Determination of progesterone in milk on day 21–24 is a good means for detecting non-pregnant cows.     

Epidermal growth factor contents in human milk,cow's milk and cow's-milk-based infant formulas

AIM: To determine EGF contents in human milk, frech cow's milk and cow's milk-based infant formulas and the relationship between EGF content of human milk and neonatal maturity. METHODS: EGF contents in 57 human colostrum from mothers delivering prematurely and at term, 4 different fresh cow's milk and 8 different cow's-milk-based infant formulas with hydrolyzed and non-hydrolyzed proteins were determined by radioimmunoassay (RIA). RESULTS: Human milk from mothers of premature infants had higher EGF content compared to that from mothers of term infants . There was a negative correlation between EGF content of human milk and gestational age, birth weight of neonates. The values in fresh cow's milk were similar to that in human term milk. The contents in non-hydrolyzed protein formulas were much lower than that in human milk and fresh cow's milk. No immunoreactive EGF was detected in all hydrolyzed protein formulas. CONCLUSION: The occurrence of high EGF concentration in premature milk may represent a maternal compensatory mechanism to accelerate the growth and maturation in immature infants. Lack of EGF in formulas suggests that they may not suitable for those newborns with immature or damaged gastrointestinal tract.