Biomedical subjects
Publications and source records attributed to R V Short.
The volume of the left and right breasts was measured daily in four nulliparous women during normal menstrual cycles and after the use of oral contraceptives. Breast volume increased significantly in the second half of both normal and contraceptive-controlled cycles. The mean total change in volume throughout the cycle was 100 ml under natural conditions and 66 ml on oral contraceptives.
Explore the source record for details and available documents.
A detailed investigation of testicular meiosis in a mule, a hinny and a Przewalski horse/domestic horse hybrid were made. Abnormalities of pairing were observed in the mule and hinny in most germ cells at the pachytene stage of meiotic prophase, and spermatogenesis was alsmot totally arrested. A few mature spermatozoa were recovered from the ejaculate and epididymal flushings of the hinny. The Przewalski horse/domestic horse hybrid was fertile and showed normal spermatogenesis. Chromosome banding studies showed a close homology between the karyotypes of the Prezwalski horse (Equus przewalskii, 2n = 66) and the domestic horse (E. caballus, 2n = 64), and it is evident that a single Robertsonian translocation has occurred transforming four acrocentric chromosomes of E. przewalskii into two metacentric chromosomes in E. caballus. The investigations showed that a trivalent is formed at meiosis in the hybrid (2n = 65), segregation from which gives two classes of genetically balanced spermatozoa. Both of these are capable of producing normal offspring if they fertilize the eggs of a domestic mare.
Chromosomal abnormalities have been detected in seven mares isolated by their poor reproductive performance. All had small or rudimentary gonads and absent or irregular oestrous cycles. Two mares had an XO genotype, one was a 65,XXX female and another a 64,XY sex-reversed female. Two other mares were sex chromosome mosaics of the 63,X/64,XX type. The seventh mare showed a normal female karyotype but a small extra autosomal fragment was found in a few cells.
The infertility of the mule has proved a continuing challenge to scientific thought. Since the chromosomal differences between the two parental species are so great as to render normal meiosis impossible, it is postulated that all mules and hinnies are sterile. The problem now is to explain how mules and hinnies can occasionally produce spermatozoa or ova. The appearance of the mule was sufficient to persuade the ancients that both parents, not just the male, must contribute to the make-up of the offspring. The mule has also taught us that, when the number of oocytes in the ovary is reduced, the ovary becomes the time-clock that regulates the length of the oestrous cycle. A study of gonadotrophin production in horses and donkeys bearing hybrid foals has yielded fascinating results about the immunology of pregnancy. The behaviour of the sex chromosomes of female mules and hinnies has helped to confirm the Lyon hypothesis about X-chromosome inactivation. The mule has also provided spectacular proof of the doctrine of hybrid vigour, and the marked deficiency of males at birth confirms the general truth of Haldane's Law. The mule and the hinny remain man's only successful attempt at the production of a commercially viable interspecific mammalian hybrid.
Explore the source record for details and available documents.
Human granulosa cells growing in culture were used to study the effects of sera from twenty-three patients with idiopathic Addison's disease. There were two women with primary amenorrhoea, thirteen with premature ovarian failure following a normal menarche, and one man with testicular atrophy in this group. The sera from all twenty-three patients contained antibodies which reacted with fresh sections of human corpus luteum using an in vitro immunoflorescence test. Serum fron nine of the twenty-three patients contained antibodies which were cytotoxic to human granulosa cells in tissue culture; the cytotoxic effect was complement dependent, and related to the immunofluorescent staining properties of the serum and dilution of antibody present. No cytotoxic effect was observed when granulosa cells were cultured in serum from the remaining fourteen Addisonian patients, or from normally menstruating women, post-menopausal women or in serum containing organ-specific antibodies to other endocrine tissues. The cytotoxic effect was paralleled by a fall in progesterone production by the granulosa cells. The production of progesterone by cells cultured in any of the non-cytotoxic sera was significantly greater than that produced by cells in the presence of cytotoxic antibody.
Explore the source record for details and available documents.