Health Sciences Center
Hospital and Clinic
Primate Center
Public Health
Tropical Medicine

(Reproductive Physiology)

Professor
Ph.D.: Michigan State University

Primary research interests are directed towards three main areas:

maternal-fetal transmission of viruses, interrelationship of reproductive hormones to the immune system,and cryopreservation of nohuman primate gamates and early embryos.

Maternal-Fetal Transmission of Viruses

Some viruses, such as HIV, infect infants either (1) through transplacental passage of the virus during gestation or (2) during the birth process. The presence of antibodies in the newborn may be maternal antibodies that have crossed the placenta in utero. Detection of virus particles in the newborn are indicative of in utero infection only if it can be established that infection did not occur at birth. Collaborative studies with Dr. Michael Murphey-Corb in Microbiology involve time-breeding sessions, ultrasound detection of pregnancy and gestational growth, and infection of mothers prior to or at various times after conception.

Interrelationship of Reproduction Hormones and the Immune System

rogesterone is reported to have immunosuppressive properties. Studies are directed towards determining if the immune responsiveness of lymphocytes is changed during normal menstrual cycles, during prolonged periods of estrogen or progesterone maintenance, or in castrated nonhuman primates. Such studies may be useful in explaining cyclic infections in women especially urinary tract infections in elderly females.

Cryopreservation of Nonhuman Primate Gametes and Embryos.

These studies include both those directed at the control of ovulation and cryopreservation of nonhuman primate sperm.

The time of ovulation can be preselected in rhesus and patas monkeys by the administration and withdrawal of exogenous progesterone. Future studies will be directed towards a more precise delimitation of the time of ovulation by non-invasive procedures and means for detecting the pregnancy within 14-16 days after ovulation.

No term pregnancies have been reported in nonhuman primates as a result of artificial insemination using post-thawed cryopreserved sperm. We have found that good motility immediately upon thawing does not mean that the sperm will remain motile for more than an hour. Current efforts are directed towards changes in the methods used to dehydrate the sperm before freezing and for rehydration immediately after thawing. Collaborative efforts are also directed towards the establishment of a cryobank of gametes and early embryos.

Recent Publications:

A PubMed listing of research publications for Richard M. Harrison, Ph.D.

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