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Biomedical subjects

E F Graham

Publications and source records attributed to E F Graham.

At least 55 records · Page 3Linked to original sources
PubMed1978

Current status of semen preservation in the ram, boar and stallion.

From the studies cited it was concluded that short and long term preservation of stallion semen has encountered major obstacles. Fertilizing capacity of extended or extended and cooled spermatozoa has been impaired. With the hydrogen ion extenders, the fertility was depressed either with or without glycerol when the semen was inseminated immediately after extension. With the cream-gel extender, fertility was not impaired when inseminated immediately after extension, but was impaired after storage at 5 C for 24 hr or in the presence of glycerol. The fertilizing capacity of extended frozen spermatozoa particularly from some stallions has been more adversely affected than that of others. These studies show that the pregnancy rate range was from 50 to 80% for raw semen from the same stallion used in the frozen studies. Pregnancy rate with this magnitude of difference must be carefully weighed in applying the results from a few stallions to the population. Sufficient information has been generated to suggest that the preservation of stallion spermatozoa is possible but the fertilizing capacity is impaired. Causes of this impairment must be further investigated. When this is accomplished, the number of motile spermatozoa needed per insemination and the frequency of insemination required for optimal fertilization reported in this review must then be reevaluated.

Animals↗
PubMed1976

Freeze-drying of spermatozoa.

Bull semen was diluted to a concentration of 2 X 10(8) cells/ml, cooled to 5 degrees C in 5 h, frozen in 0.025 ml spheres on the surface of solid carbon dioxide, and stored in liquid nitrogen. 50% by volume of the diluent was 325 m0sm Tes:N-tris (hydroxymethyl) methyl-2-amino ethane sulfonic acid titrated to pH 7.2 with 325 m0sm Tris:tris (hydroxymethyl) amino methane. The diluent also contained 30% by volume isotonic sodium citrate and 20% by volume egg yolk. The frozen spermatozoa were freeze-dried in 400 mg quantities in test tubes at -50 degrees C with a condenser at -196 degrees C. Moisture content was determined by weighing the individual samples before and after freeze-drying. Drying the samples for several days at 20 degrees C removed 868 mg from each gram of frozen material and this was considered the zero moisture level. Samples were stored at 20 degrees C or -196 degrees C after freeze-drying. The freezer-dried samples were rehydrated by flooding with five times their original volume of isotonic sodium citrate. Tests of the recovered spermatozoa included percentage motile cells, acrosome damage, enzyme release, protein denaturation, hypotonic swelling and fertility testing. Sperm motility decreased with dryness until it reached zero at 3% moisture. Acrosome morphology and enzyme release appeared normal down to 1% moisture. Preliminary results showed some fertility at all levels of dryness with -196 degrees C storage, and fertility at less than 1% moisture with 20 degrees C storage. Additional fertility testing is underway.

Animals↗
PubMed1975

Effect of low doses of alpha-chlorohydrin on fertility and semen characteristics and binding of the drug of spermatozoa in swine.

Daily feeding of 1 mg of alpha-chlorohydrin per kg body weight to boars prevented fertility completely when the ejaculate was used for insemination. The semen charactreated than in untreated boars, but the sperm morphology was otherwise normal. In vitro addition of 5 mg/epididymal contents from the treated boars revealed normal Na+, K+ and glycerylphosphorylcholine concentrations. The movement of sperm cytoplasmic droplets was completed on all spermatozoa more distally in treated than in untreated boars, but the sperm morphology was otherwise normal. In vitro addition of 5 mg/100 ml of alpha-chlorohydrin to ejaculate boar semen completely inhibited and 2.5 mg/100 ml decreased fertility. Removal of the alpha-chlorohydrin prior to insemination partially restored fertility. 14C-alpha-chlorohydrin was shown to be more firmly bound to boar spermatozoa than 14C-carboxyinulin and could not be removed from the spermatozoa with 3 washings. The contraceptive mechanism of the drug is suggested to be alkylation of the sperm membrane by free alpha-chlorohydrin in the epididymis.

Animals↗