排序方式： 共有24条查询结果，搜索用时 31 毫秒
1.
2.
3.
Biological potencies of three 29 amino acid growth hormone-releasing hormone analogs (GHRH[1-29]) were determined in the bovine and compared to synthetic human GHRH (44 amino acids; hGHRH[1-44]NH2) for their ability to increase serum growth hormone (GH) concentrations. Four prepubertal Holstein heifers (179 +/- 10 kg) received hGHRH(1-44)NH2 or analogs (D-Ala2, Nle27, Agm29 GHRH[1-29], [JG-73]; D-N-MeAla2, Nle27, Agm29 GHRH[1-29], [JG-75]; and desamino-Tyr1, D-Ala2, Nle27, Agm29 GHRH[1-29], [JG-77]) at the following doses: 0, 6.25, 25, 100 and 400 micrograms/animal. All treatment-dose combinations were administered to each heifer with at least a 1-d interval between treatments. Sixteen blood samples were collected via jugular cannulas 20 min before and up to 6 h after treatment injection. There was a linear dose-dependent GH release in response to hGHRH(1-44)NH2 and the three analogs. Growth hormone peak amplitudes for the three analogs were similar to those observed after administration of the hGHRH(1-44)NH2 (P greater than .05). However, when total area under the GH response curves for each treatment was averaged over all the doses, JG-73 stimulated greater GH release than hGHRH(1-44)NH2 (P less than .05) Heifers injected with the 400-microgram dose of hGHRH(1-44)NH2 or the three analogs showed a primary release of GH followed by a secondary release 1 h later. At all other doses, only a primary GH release was observed.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
4.
F Minervini R Guastamacchia F Pizzi ME Dell’Aquila VL Barile 《Reproduction in domestic animals》2013,48(2):317-324
Flow cytometry is a useful tool that provides an accurate, objective and rapid evaluation of semen quality. The use of this technique could significantly improve the quality of buffalo semen samples used in artificial insemination. This study was carried out to evaluate, by flow cytometry, frozen–thawed buffalo spermatozoa quality parameters such as sperm viability by SYBR‐14/propidium iodide staining; mitochondrial function by JC‐1 potentiometric probe; sperm chromatin stability (SCSA) by acridine orange; and acrosome reaction (AR) by FITC‐PNA staining. Semen samples from five Italian Mediterranean buffalo bulls were used. Sperm viability was not different between bulls and ranged from 33.4% to 43.6%. A consistent rate (55.1 ± 10.8%) of sperm cells showed high mitochondrial membrane potential (Δψhigh), with no significant differences between subjects. Sperm chromatin structure assay differed significantly between the five buffalo bulls; moreover, data showed high stability within each buffalo. DNA fragmentation indexes (DFI), such as %‐DFI, ‐DFI, SD‐DFI, were 11.2 ± 8.6, 153.3 ± 24.6 and 81.6 ± 21.2, respectively. Regarding AR, the percentage of acrosome‐reacted live (ARL) and acrosome‐reacted dead (ARD) spermatozoa was 0.3 ± 0.2 and 15.3 ± 5.5, respectively. This functional parameter differed significantly between buffalo bulls and showed high stability. Following to Ca2+ ionophore A23187 for 3 h, AR significantly differed between subjects and was characterized by an increase in both ARL (10.8%) and ARD population (22.0%). This study indicates that flow cytometry could be a useful tool for a quick multiparametric evaluation of sperm quality in buffalo. In particular, SCSA and AR resulted in sperm functional parameters sensitive enough for the diagnosis of frozen‐thawed semen fertilizing potential. 相似文献
5.
6.
D M Grieger R Scarborough D M deAvila H E Johnson J J Reeves 《Journal of animal science》1990,68(11):3755-3764
Objectives were to evaluate the dose (Exp. 1) and purity of LH preparations (Exp. 2) on the anti-LH antibody response in heifers. Experiment 3 evaluated the longevity of LH immunization on sterility in heifers. In Exp. 1, 115 crossbred heifers were injected every 3 wk for 6 wk with .1, .33, 1.0, 3.0 or 9.0 mg of LH-ovalbumin. Concentrations of anti-LH antibodies generated were quantified by determining the percentage of binding of [125I]LH in serum. Mena LH binding over wk 0 to 12 was greater in heifers immunized with 1.0 mg conjugate than in heifers immunized with other doses (P less than .05). In Exp. 2, LH-ovalbumin conjugates were made from either LH-1, LH-2 or LH-3, which had relative immunological potencies of 2.1, 1.5 and 1.2 x NIH-LH-S1 units/mg, respectively. Forty-eight crossbred beef heifers were immunized against one of these three LH-ovalbumin conjugates, against LH conjugated without ovalbumin (LH-LH), or against ovalbumin alone (Oval). Estrous cycle activity was monitored by measuring serum progesterone concentration. Potency of the LH preparation used in the LH-ovalbumin conjugate was correlated (r = .94) with its ability to produce LH antibodies. In Exp.3, heifers were injected with 1 mg antigen every 2 wk for 10 wk. Five LH-1 heifers and five control heifers were slaughtered for examination of ovaries 10 wk after the last booster injection. The remaining five LH-I and five control animals were placed with a bull 8 wk after the last booster. All five control heifers conceived by 4 +/- 1 wk after placement with the bull whereas the LH-immunized heifers remained acyclic for 42 to 96 wk. 相似文献
7.
Long‐term Effects of Pyrethrin and Cyfluthrin,a Type II Synthetic Pyrethroid,Insecticide Applications on Bull Reproductive Parameters 
下载免费PDF全文
下载免费PDF全文 JL Stewart CF Shipley FA Ireland VL Jarrell CL Timlin DW Shike TL Felix 《Reproduction in domestic animals》2016,51(5):680-687
The objectives of this study were to determine effects of cyfluthrin and pyrethrin spray products, used in combination with cyfluthrin topical and ear tag applications, on bull reproductive parameters over 18 weeks. Angus or Angus x Simmental bulls were randomly assigned to one of three treatment groups: (i) no exposure to pyrethrins/cyfluthrin (CONT; n = 10), (ii) cyfluthrin ear tag and topical applications (ET; n = 10), or (iii) cyfluthrin ear tag, topical, premise spray and pyrethrin fog spray applications (ET+S; n = 8). Bull body weight was measured every 3 week, and body condition score and scrotal circumference were recorded on weeks 0, 9 and 18. Semen and serum were collected every 3 weeks for sperm evaluation and testosterone measurement, respectively. There was a treatment × week interaction (p < 0.01) for sperm with primary defects; bulls in CONT group had a greater (p = 0.01) percentage of sperm with primary defects than bulls treated with insecticides at week 18. Overall and progressive sperm motility, normal sperm morphology, secondary sperm defects and serum testosterone concentrations changed (p < 0.01) over time in all bulls; however, treatment did not affect (p ≥ 0.13) any of these parameters. There were also no treatment effects (p ≥ 0.08) on bull body weight, body condition score or scrotal circumference. The use of pyrethrin‐ and cyfluthrin‐based insecticides, regardless of application, did not negatively affect reproductive parameters in beef bulls when administered over 18 weeks. 相似文献
8.
OBJECTIVES: This paper describes the development of an online questionnaire for testing nutrition professionals' perceptions of the 'healthiness' of individual foods and the results of administering that questionnaire. The questionnaire was designed to produce a standard ranking of foods that can be used as a tool for testing nutrient profile models. DESIGN: The questionnaire asked respondents to categorise 40 foods (from a master list of 120) in one of six positions, ranging from less to more healthy. The 120 foods were selected to be representative of the British diet. The questionnaire was sent via email to nutrition professionals from the British Dietetic Association and the (British) Nutrition Society. RESULTS: Eight hundred and fifty responses were received. These responses were used to rank the 120 foods by the average score which they received from the nutrition professionals. A regression analysis was also carried out to examine the relationship between the scores awarded by the nutrition professionals and various features of the foods: their nutritional content, their average serving size, their frequency of consumption, whether they were drinks or foods, etc. Nearly 50% of the variance in the average scores was explained by the nutritional content of the foods. When other variables were included in the analysis the percentage of variance that was explained increased to 64%. CONCLUSIONS: The average scores of the foods produce a standard ranking, which can be used as a tool for validating and comparing nutrient profile models. The regression analysis provides some information about how nutrition professionals rank the 'healthiness' of individual foods. 相似文献
9.
OBJECTIVE: To compare nutrient profile models with a standard ranking of 120 foods. DESIGN: Over 700 nutrition professionals were asked to categorise 120 foods into one of six positions on the basis of their healthiness. These categorisations were used to produce a standard ranking of the 120 foods. The standard ranking was compared with the results of applying eight different nutrient profile models to the 120 foods: Models SSCg3d and WXYfm developed for the UK Food Standards Agency, the Nutritious Food Index, the Ratio of Recommended to Restricted nutrients, the Naturally Nutrient Rich score, the Australian Heart Foundation's Tick scheme, the American Heart Association's heart-check mark and the Netherlands tripartite classification model for foods. Rank correlation was assessed for continuous models, and dependence was assessed for categorical models. RESULTS: The continuous models each showed good correlation with the standard ranking (Spearman's rho = 0.6-0.8). The categorical models achieved high chi(2) results, indicating a high level of dependence between the nutrition professionals' and the models' categorisations (P < 0.001). Models SSCg3d and WXYfm achieved higher scores than the other models, implying a greater agreement with the standard ranking of foods. CONCLUSIONS: The results suggest that Models SSCg3d and WXYfm rank and categorise foods in accordance with the views of nutrition professionals. 相似文献
10.
Physiological role of silent receptors of atrial natriuretic factor 总被引：33，自引：0，他引：33
T Maack M Suzuki F A Almeida D Nussenzveig R M Scarborough G A McEnroe J A Lewicki 《Science (New York, N.Y.)》1987,238(4827):675-678
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. 相似文献