Fractionation of sperm
First Claim
1. A process for increasing the proportion of Y-sperm in mammalian sperm, which comprises the steps of a) maintaining at least the sperm portion of progressively motile sperm-containing semen, either as such or suspended in an aqueous suspending vehicle physiologically acceptable to the sperm, as an upper layer in vertical interfacial contact, at a temperature at which the motile sperm are motile, with a lower discrete layer of a first aqueous contacting medium physiologically acceptable to the sperm and in which the motile sperm migrate downwardly at a slower rate than in the upper layer, until a portion only of the motile sperm of the semen having migrated downwardly into the contacting medium, thereby producing a contacting medium containing a higher proportion of Y to X sperm than in the starting sperm, and b) repeating the step at least once, employing in the upper layer the motile sperm which have migrated to the first aqueous contacting medium and as the lower layer a second aqueous contacting medium physiologically acceptable to the sperm and in which the motile sperm migrate downwardly at a slower rate than in the first contacting medium.
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Accused Products
Abstract
Motile sperm are separated from immotile and abnormal sperm of mammalian semen by maintaining, at a temperature at which the motile sperm are motile, a layer of at least the sperm portion of the semen in interfacial contact with a discrete lower layer of an aqueous contacting medium physiologically acceptable to the sperm in which the motile sperm have a lower migration rate than in the upper layer, until the motile sperm of the semen have migrated at a preferential rate to the contacting medium, thereby providing a sperm fraction consisting essentially of normal motile sperm with enhanced Y-sperm content. Repeating the process with a second contacting medium physiologically acceptable to the sperm which further retards the migration rate of the motile sperm increases substantially the Y- to X-sperm ratio of the sperms which migrate thereto. The resulting sperm fraction, because of its enhanced Y-sperm content, can be used for artificial insemination to increase the incidence of male offspring. The first step alone can be used to improve the quality of semen having an abnormally low normal motile sperm content, thereby increasing the chances of a successful insemination.
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Citations
37 Claims
- 1. A process for increasing the proportion of Y-sperm in mammalian sperm, which comprises the steps of a) maintaining at least the sperm portion of progressively motile sperm-containing semen, either as such or suspended in an aqueous suspending vehicle physiologically acceptable to the sperm, as an upper layer in vertical interfacial contact, at a temperature at which the motile sperm are motile, with a lower discrete layer of a first aqueous contacting medium physiologically acceptable to the sperm and in which the motile sperm migrate downwardly at a slower rate than in the upper layer, until a portion only of the motile sperm of the semen having migrated downwardly into the contacting medium, thereby producing a contacting medium containing a higher proportion of Y to X sperm than in the starting sperm, and b) repeating the step at least once, employing in the upper layer the motile sperm which have migrated to the first aqueous contacting medium and as the lower layer a second aqueous contacting medium physiologically acceptable to the sperm and in which the motile sperm migrate downwardly at a slower rate than in the first contacting medium.
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22. A process for increasing the proportion of motile to immotile sperm in mammalian sperm, which comprises the steps of a) separating the sperm from the other components of the semen;
- b) suspending the separated sperm portion of the semen in an aqueous suspending vehicle physiologically acceptable to the sperm and which does not substantially retard the downward migration rate of motile sperm;
c) maintaining the sperm-containing suspending vehicle as an upper layer in interfacial contact, at a temperature at which the motile sperm are motile, with a lower discrete layer of an aqueous contacting medium which is physiologically acceptable to the sperm and in which the motile sperm migrate downwardly at a slower rate than in the suspending vehicle, until at least a portion of the motile sperm of the separated sperm have migrated downwardly into the contacting medium, thereby producing a sperm fraction having a higher proportion of motile sperm than in the starting sperm; and
d) thereafter separating the contacting medium, containing the motile sperm enhanced fraction of the starting sperm, from the suspending vehicle layer. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
- b) suspending the separated sperm portion of the semen in an aqueous suspending vehicle physiologically acceptable to the sperm and which does not substantially retard the downward migration rate of motile sperm;
Specification