Cryopreservation of Immature Bovine Oocytes to Reconstruct Artificial Gametes by Germinal Vesicle Transplantation     

AM Luciano  F Franciosi  V Lodde  F Perazzoli  M Slezáková  S Modina 《Reproduction in domestic animals》2009,44(3):480-488

Joining immature gamete cryopreservation and germinal vesicle transplantation (GVT) technique could greatly improve assisted reproductive technologies in animal breeding and human medicine. The present work was aimed to assess the most suitable cryopreservation protocol between slow freezing and vitrification for immature denuded bovine oocytes, able to preserve both nuclear and cytoplasmic competence after thawing. In addition, the outcome of germinal vesicle transfer procedure and gamete reconstruction was tested on the most effective cryopreservation system. Oocytes, isolated from slaughterhouse ovaries, were stored after cumulus cells removal either by slow freezing or by vitrification in open pulled straws. After thawing, oocytes were matured for 24 h in co-culture with an equal number of just isolated intact cumulus enclosed oocytes, and fixed in order to evaluate the stage of meiotic progression and cytoskeleton organization. Our results showed that after warming, vitrified oocytes reached metaphase II (MII) in a percentage significantly higher than oocytes cryopreserved by slow freezing (76.2% and 36.5% respectively, p < 0.05). Moreover, vitrification process preserved the organization of cytoskeleton elements in a higher proportion of oocytes than slow freezing procedure. Therefore vitrification has been identified as the elective method for denuded immature oocytes banking and it has been applied in the second part of the study. Our results showed that 38.3% of oocytes reconstructed from vitrified gametes reached the MII of meiotic division, with efficiency not different from oocytes reconstructed with fresh gametes. We conclude that vitrification represents a suitable method of GV stage denuded oocyte banking since both nuclear and cytoplasmic components derived from cryopreserved immature oocytes can be utilized for GVT.  相似文献   

Sulfur-associated polioencephalomalacia in cattle grazing plants in the Family Brassicaceae     

RA McKenzie  AM Carmichael  ML Schibrowski  SA Duigan  JA Gibson  JD Taylor 《Australian veterinary journal》2009,87(1-2):27-32

Polioencephalomalacia was diagnosed histologically in cattle from two herds on the Darling Downs, Queensland, during July–August 2007. In the first incident, 8 of 20 18-month-old Aberdeen Angus steers died while grazing pastures comprising 60% Sisymbrium irio (London rocket) and 40% Capsella bursapastoris (shepherd's purse). In the second incident, 2 of 150 mixed-breed adult cattle died, and another was successfully treated with thiamine, while grazing a pasture comprising almost 100% Raphanus raphanistrum (wild radish). Affected cattle were either found dead or comatose or were seen apparently blind and head-pressing in some cases. For both incidents, plant and water assays were used to calculate the total dietary sulfur content in dry matter as 0.62% and 1.01% respectively, both exceeding the recommended 0.5% for cattle eating more than 40% forage. Blood and tissue assays for lead were negative in both cases. No access to thiaminase, concentrated sodium ion or extrinsic hydrogen sulfide sources were identified in either incident. Below-median late summer and autumn rainfall followed by above-median unseasonal winter rainfall promoted weed growth at the expense of wholesome pasture species before these incidents.  相似文献   

Activated coagulation times in normal cats and dogs using MAX-ACT^TM tubes     

AM See  KL Swindells  MJ Sharman  KL Haack  D Goodman  A Delaporta  I Robertson  SF Foster 《Australian veterinary journal》2009,87(7):292-295

Objective  To establish reference values for activated coagulation time (ACT) in normal cats and dogs, by visual assessment of clot formation using the MAX-ACT^TM tube.
Subjects  We recruited 43 cats and 50 dogs for the study; 11 cats and 4 dogs were excluded from the statistical analysis because of abnormalities on clinical examination or laboratory testing including anaemia, prolonged prothrombin time (PT) or activated partial thromboplastin time (APTT), or insufficient plasma volume for comprehensive laboratory coagulation testing.
Procedure  Blood samples were collected via direct venipuncture for MAX-ACT, packed cell volume/total solids, manual platelet estimation and PT/APTT measurement. Blood (0.5 mL) was mixed gently in the MAX-ACT tube at 37°C for 30 s, then assessed for clot formation every 5 to 10 s by tipping the tube gently on its side and monitoring for magnet movement. The endpoint was defined as the magnet lodging in the clot. The technique was tested with 10 dogs by collecting two blood samples from the same needle insertion and running a MAX-ACT on each simultaneously.
Results  In normal cats the mean MAX-ACT was 66 s (range 55–85 s). In normal dogs the mean was 71 s (range 55–80 s). There was no statistical difference between the first and second samples collected from the same needle insertion.
Conclusions and Clinical Relevance  In both cats and dogs, a MAX-ACT result >85 s should be considered abnormal and further coagulation testing should be performed. Additionally, failure to discard the first few drops of the sample does not appear to significantly affect results.  相似文献   

Transposition of gram-positive transposon Tn916 in Acholeplasma laidlawii and Mycoplasma pulmonis   总被引：16，自引：0，他引：16  

K Dybvig  G H Cassell 《Science (New York, N.Y.)》1987,235(4794):1392-1394

Mycoplasma genetics has been limited by a lack of genetic tools such as selectable markers, methods to transfer DNA, and suitable vectors for cloning. Studies were undertaken to examine the potential of using the streptococcal transposon Tn916 as a mycoplasma genetic tool. The Escherichia coli plasmid pAM120, which contains Tn916, was transformed into Acholeplasma laidlawii and Mycoplasma pulmonis. Transposition of Tn916 into the mycoplasma chromosome apparently occurred by an excision-insertion mechanism. This example shows that newly introduced DNA from other bacteria can be successfully expressed in mycoplasma and that Tn916 should serve as a powerful genetic tool for the study of mycoplasmas.  相似文献   

A new agent-based model provides insight into deep uncertainty faced in simulated forest management     

Sotnik  Garry  Cassell  Brooke A.  Duveneck  Matthew J.  Scheller  Robert M. 《Landscape Ecology》2022,37(5):1251-1269

Landscape Ecology - Exploratory modeling in forestry uses a variety of approaches to simulate forest management. One important assumption that every approach makes is about the deep...  相似文献   

欧拉羊与山谷型藏羊杂交F_1代羔羊补饲兼放牧育肥试验效果观察     

赵君  让闹日  郭淑珍  马登录  牛小莹  李保民  石少英  尕旦吉  张亚林  李春堂  张海滨 《畜牧兽医杂志》2011,30(3):24-25

用欧拉羊杂交改良山谷型藏羊,对杂交F1代羔羊补饲兼放牧育肥试验,补饲阶段试验结果表明：经过90 d补饲,试验组增重10.88kg,比对照组高4.32 kg（P〈0.01）,平均日增重0.121 kg,比对照组高0.048 kg;放牧育肥阶段试验结果表明：经过3个月放牧育肥,试验组增重9.09 kg,比对照组高2.67 kg（P〈0.05）,平均日增重0.101 kg,比对照组高0.03 kg。  相似文献   

Growth of epitaxial nanowires at the junctions of nanowalls     

Ng HT  Li J  Smith MK  Nguyen P  Cassell A  Han J  Meyyappan M 《Science (New York, N.Y.)》2003,300(5623):1249

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Lesion-induced sprouting in the rat dentate gyrus is inhibited by repeated ethanol administration     

West JR  Lind MD  Demuth RM  Parker ES  Alkana RL  Cassell M  Black AC 《Science (New York, N.Y.)》1982,218(4574):808-810

The effect of ethanol on hippocampal axonal sprouiting was studied with a histochemical technique for identifying acetylcholinesterase. Unilateral lesion of the entorhinal cortex in adult rats produced an increase in the density of acetylcho-linesterase staining in the outer molecular layer and a concomitant increase in the width of the pale-staining commissural-associational zone of the dentate gyrus. Other rats were given ethanol (11.3 +/- 0.45 grams per kilogram) for 2 weeks before and 9 days after receiving the lesion. Ethanol abolished the expansion of the commissural-associational zone. The effect of ethanol on sprouting axons suggests that it may inhibit recovery of function after brain injury.  相似文献   

Clinical report: hyperplastic adipose lids in mackerel scad, Decapterus macarellus (Cuvier)     

Boylan SM  Harms CA  Waltzek T  Law JM  Garner M  Cassell J  Fatzinger MH  Govett P 《Journal of fish diseases》2011,34(12):921-925

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Tiger snake (Notechis scutatus) envenomation in a horse     

AM Cullimore  GD Lester  KL Swindells 《Australian veterinary journal》2013,91(9):381-384

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