A Programme for Oestrus Synchronization and Embryo Transfer in Sheep     

B. Larsson  A. Gustafsson  A. Nasholm  L. Bjurström 《Reproduction in domestic animals》1991,26(6):301-308

Eighty-five animals were used to develop an embryo transfer programme including a study on how oestrus synchronization influenced the ovulation rate. The animals, both ewes and ewe lambs, were divided into three groups: donors, recipients and controls. Oestrus was synchronized in donors and recipients by the use of progesterone-impregnated vaginal pessaries. The donors also received one injection of 600 IU PMSG. Samples for microbiological investigation of the vaginal flora were taken in connection with synchronization. The ovulation rate was determined by laparoscopy in the control animals and by laparotomy in the donors and recipients. The embryos were surgically recovered from the donors by flushing of the uterine horns seven days after pessary removal. The embryos were classified according to developmental stage and quality. At transfer each recipient received 2–4 embryos (moruhs or blastocysts) by a surgical method. A ± 1 day asynchrony in oestrus between donors and recipients was tolerated. All synchronized animals came into oestrus within 2.5 days after pessary removal. The interval was shorter if the animals had been injected with PMSG. The largest number of ovulations occuwed in the synchronized and PMSG-treated animals (mean 4.5 ± 2.1). Synchronized animals that did not receive PMSG had almost the same ovulation rate as the control animals (2.6 ± 0.9 versus 2.5 ± 0.7). The pessary treatment influenced the bacterial flora of the vagina. The number of ewes with bacterial growth in the vagina increased. The number of isolated organisms also increased. The embryo recovery rate was 80.8% and 3.7 ± 2.7 ovas was recovered on average. Eighty-eight percent of all donors yielded transferable embryos. Morulas and blastocysts comprised 84.4% of the recovered oocytes/embryos. Only 5.2% of these were of poor quality. Of the transferred embryos, 65.1% developed into lambs and 91.3% of the recipients lambed. The ewe lambs were as suitable as donors and recipients as the older ewes.  相似文献   

The use of remote sensing and geographic information systems in UNICEF's dracunculiasis (Guinea worm) eradication effort   总被引：1，自引：0，他引：1  

Keith C. Clarke  Jeffrey P. Osleeb  James M. Sherry  Jean Pierre Meert  Robert W. Larsson 《Preventive veterinary medicine》1991,11(3-4):229-235

Dracunculiasis (Guinea worm disease) is a parasitic disease which is endemic in 18 African and two Asian countries. It has a marked potential for eradication by a combination of water supply management, health education and controlled medical intervention. While data on the disease are, in many cases, both in short supply and unreliable, increasingly the tools of remote sensing and geographic information systems (GIS) are becoming important components of the eradication effort. In particular, remotely sensed data from LANDSAT have allowed the identification and location of remote and small settlements in dracunculiasis-endemic areas. When coupled with additional information available in remotely sensed data from LANDSAT, and when used in conjunction with a GIS containing digitized maps and field data collected from hand-held global positioning system receivers, the eradication effort has developed an epidemiological tool of potential power. While at first this system is finding uses in managing existing data in a unified inventory, the system shows potential for use as an effective management decision-making tool as the control effort moves from disease reduction to disease eradication. This paper will use a single province within one country, the Zou Province of Benin, to demonstrate the varied data sources involved in the system, the software and hardware components of the system, and to discuss the specific problems involved in using the system in the field. Of particular consideration, and of potential use to other similar programs, is a consideration of the management and implementation of the system. The paper concludes that a combination of remote sensing and GIS technologies offers the epidemiologist a new and important means by which to effectively implement solutions to public health management problems.  相似文献   

CULTURE OF BOVINE IVM/IVF EMBRYOS UP TO BLASTOCYST STAGE IN DEFINED MEDIUM USING INSULIN, TRANSFERRIN AND SELENIUM OR GROWTH FACTORS     

M. Shamsuddin  B. Larsson  H. Rodriguez-Martinez 《Reproduction in domestic animals》1993,28(3):209-210

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In vitro production of antibodies to bovine virus diarrhoea virus by peripheral blood mononuclear cells from cattle immunized by infection     

B Larsson  C Fossum  N Juntti 《Veterinary microbiology》1990,22(2-3):161-170

A method for in vitro production of antibodies to bovine virus diarrhoea virus (BVDV) by peripheral blood mononuclear cells (PBMC) was developed. The PBMC were cultured in microtitre plates coated with detergent-solubilized BVDV and the supernatants were tested in an enzyme-linked immunosorbent assay which detects IgG antibodies to BVDV. Following incubation of PBMC with an optimal concentration of pokeweed mitogen for 5 days, antibodies to BVDV were detected in culture supernatants of PBMC from immune cattle, but not in supernatants of PBMC from seronegative cattle, from persistently BVDV-infected cattle or from a 5-day-old calf that received BVDV antibodies via colostrum. This antibody-production assay may therefore be used as a tool to discriminate between passively acquired antibodies and those actively induced.  相似文献   

Ultrastructure of the Uterotubal Junction in Preovulatory Pigs   总被引：2，自引：0，他引：2  

H. Rodriguez-Martinez  L. Nicander    S. Viring    S. Einarsson  K. Larsson  † 《Anatomia, histologia, embryologia》1990,19(1):16-36

The ultrastructure of the surface epithelia from the uterotubal junction (UTJ), and the adjacent tubal isthmic and endometrial regions, was studied in preovulatory oestrus gilts, either unmated or inseminated 12 h before with fresh boar semen. The simple columnar epithelium of the UTJ consisted of non-ciliated (secretory) and ciliated cells. Secretory vesicles occurred in the secretory cells, especially in inseminated gilts. Lymphocytes, monocytes and macrophages were found dispersed basally among the epithelial cells. Phagocytosis of epithelial cells undergoing apoptosis was seen throughout the UTJ at oestrus, increasing after insemination. Neutrophilic granulocytes were found in the lamina propria of the uterine component of the UTJ, but only occasionally in the epithelium. After insemination, neutrophils invaded the uterine epithelium, to actively participate in intraepithelial phagocytosis or move into the lumen, engulfing spermatozoa. Neutrophils were absent from the UTJ proper and the isthmic epithelium, irrespective of the presence of spermatozoa in the lumen. Those spermatozoa in the uterine lumen that escaped phagocytosis had severely damaged plasma membranes, whereas those in the UTJ proper--concentrated towards the deep furrows of the diverticulae--mostly showed normal sperm ultrastructure.  相似文献   

Performance of second-season grazing cattle following different levels of parasite control in their first grazing season     

Larsson A  Uggla A  Waller PJ  Höglund J 《Veterinary parasitology》2011,175(1-2):135-140

A 3-year grazing trial was performed during 2003-2005 on a commercial steer-producing farm in Sweden to study performance of second-season grazing (SSG) cattle following different levels of parasite exposure during their first grazing season. Initially, groups of 10 first-season grazing (FSG) cattle were each year assigned to four parasite control strategies: (1) turn-out onto pasture that during the previous year was grazed by SSG cattle, followed by a mid-July move to aftermath, (2) supplementation with concentrate and roughage for 4 weeks after turn-out, (3) no treatment, or (4) anthelmintic treatment (injectable doramectin) every fourth week. All animals were set stocked, except for those in group one. Next spring and following housing the cattle were turned out for their second grazing season onto approximately 25 ha communal pasturelands as a common mob. Weighing, faecal sampling and blood collection were performed at turn-out and then every 4 weeks for the 20-week grazing season. Faecal samples were also collected on day 10 after turn-out for detection of coccidian oocysts. Antibodies to Dictyocaulus viviparus were analysed at the time of their second housing period, and when elevated levels were recorded, stored serum samples from seropositive animals were analysed retrospectively. Results showed early-season weight losses of up to 47 kg in the SSG cattle. However, faecal egg counts were generally low and there was no correlation between SSG performance and treatment history as FSG cattle. Still, cumulative egg counts were significantly higher in animals that had been treated with anthelmintic as FSG cattle but serum pepsinogen concentrations showed no significant differences and the output of Eimeria alabamensis oocysts seldom exceeded 10,000 oocysts per gram faeces. Antibodies to D. viviparus were observed from July 2004 and from June 2005 but not in 2003. In 2004 and 2005, 64% and 83% of the animals, respectively, were seropositive for D. viviparus. It is concluded that weight gain penalties resulting from different levels of parasite infections the first grazing season remained during the second grazing season in 2004 and 2005 but no differences in weight gain could be identified in SSG cattle that had experienced different parasite control measures during their first grazing season. This was under conditions where the level of pasture infectivity was low to moderate during the second grazing period. However, D. viviparus was demonstrated in SSG animals during the two last years of the study and was an important confounding factor.  相似文献   

Transfer of learning after updating training mediated by the striatum     

Dahlin E  Neely AS  Larsson A  Bäckman L  Nyberg L 《Science (New York, N.Y.)》2008,320(5882):1510-1512

Process-specific training can improve performance on untrained tasks, but the magnitude of gain is variable and often there is no transfer at all. We demonstrate transfer to a 3-back test of working memory after 5 weeks of training in updating. The transfer effect was based on a joint training-related activity increase for the criterion (letter memory) and transfer tasks in a striatal region that also was recruited pretraining. No transfer was observed to a task that did not engage updating and striatal regions, and age-related striatal changes imposed constraints on transfer. These findings indicate that transfer can occur if the criterion and transfer tasks engage specific overlapping processing components and brain regions.  相似文献   

Pituitary gastrins occur in corticotrophs and melanotrophs   总被引：7，自引：0，他引：7  

L I Larsson  J F Rehfeld 《Science (New York, N.Y.)》1981,213(4509):768-770

The gut hormone gastrin was identified in pituitary cells containing adrenocorticotropic hormone and alpha-melanocyte--stimulating hormone by region-specific immunocytochemistry and radioimmunoassay. Smaller amounts of gastrin were found in nerve fibers of the neural lobe and pituitary stalk. Since adrenocorticotropic hormone--like peptides occur in antropyloric gastrin cells, these data indicate a considerable similarity in peptide composition of pituitary and gastrointestinal endocrine cells and reinforces questions of multiple hormone production.  相似文献   

Effects of salinity on growth and mortality of migratory and resident forms of Eurasian perch in the Baltic Sea     

Petter Tibblin  Per Koch‐Schmidt  Per Larsson  Patrik Stenroth 《Ecology of Freshwater Fish》2012,21(2):200-206

Abstract – In the coastal areas of the Baltic Sea, there are two forms of perch (Perca fluviatilis). One of the forms is migratory and spawns in streams entering the Baltic Sea. The other form is resident and spawns in brackish water. Both forms utilise the coastal habitat for foraging. We examined the spawning success of the two forms in fresh and brackish water (7‰, equal to salinity in the south Baltic Sea). The experiments showed that hatching success was equally high in freshwater and in brackish water despite female origin. The survival of yellow‐sac and free swimming fry was significantly reduced in brackish water, which was independent if the fish was of migratory or brackish resident origin. Further, growth rate of perch fry was severely reduced in brackish water. The results indicate that perch has not developed any tolerance to brackish water in the young life stages. The migratory life strategy of perch can thus be explained by higher survival of fry in freshwater.  相似文献   

Diatom derived polyunsaturated aldehydes do not structure the planktonic microbial community in a mesocosm study     

Paul C  Reunamo A  Lindehoff E  Bergkvist J  Mausz MA  Larsson H  Richter H  Wängberg SÅ  Leskinen P  Båmstedt U  Pohnert G 《Marine drugs》2012,10(4):775-792

Several marine and freshwater diatoms produce polyunsaturated aldehydes (PUA) in wound-activated processes. These metabolites are also released by intact diatom cells during algal blooms. Due to their activity in laboratory experiments, PUA are considered as potential mediators of diatom-bacteria interactions. Here, we tested the hypothesis that PUA mediate such processes in a close-to-field mesocosm experiment. Natural plankton communities enriched with Skeletonema marinoi strains that differ in their PUA production, a plankton control, and a plankton control supplemented with PUA at natural and elevated concentrations were observed. We monitored bacterial and viral abundance as well as bacterial community composition and did not observe any influence of PUA on these parameters even at elevated concentrations. We rather detected an alternation of the bacterial diversity over time and differences between the two S. marinoi strains, indicating unique dynamic bacterial communities in these algal blooms. These results suggest that factors other than PUA are of significance for interactions between diatoms and bacteria.  相似文献