Detection of altered acrosomal physiology of cryopreserved human spermatozoa after sperm residence in the female reproductive tract.

At least some of the spermatozoa that remain motile following cryopreservation have sustained sublethal damage that reduces their functional capacity in vivo. Although it is believed that acrosomal damage is partly responsible for impaired sperm function in vivo, direct evidence for this hypothesis is lacking because spermatozoa have not been collected from the female reproductive tract for evaluation. In the study reported here, cervical mucus was collected from women 24 h after artificial insemination by cervical cup. For both cryopreserved and nonfrozen inseminates, spermatozoa within the cervical mucus and spermatozoa that migrated out of mucus into culture medium (t = 1 h) were viable and had intact acrosomes. However, although nonfrozen spermatozoa did not initially respond to induction of the acrosome reaction with follicular fluid, a significant proportion of cryopreserved spermatozoa did respond. These results demonstrate that cryopreservation increases the acrosomal lability of spermatozoa residing in the female reproductive tract. An in vitro test was developed to detect this form of cryodamage. Sperm-free mucus was collected before insemination and spermatozoa from the inseminate were allowed to swim into this column of mucus in vitro. Spermatozoa recovered from this mucus sample were compared with spermatozoa from the paired sample collected from the cervix 24 h later. This in vitro test could detect acrosomal lability in cryopreserved semen samples, and this approach may prove valuable for studying sublethal cryodamage to the acrosome.

Long-term transdermal estradiol therapy: effects on endometrial histology and bleeding patterns.

Sixty postmenopausal women were enrolled in a 2-year randomized unmasked trial to determine the long-term safety of estradiol (E2) administration by a transdermal therapeutic system. Group I subjects received 0.1 mg of transdermal E2 for 24.5 days of each 28-day cycle for 96 weeks. Group II subjects received the same dosage of transdermal E2 plus 10 mg of medroxyprogesterone acetate, given orally from days 13-25 of each cycle. Vaginal bleeding patterns and endometrial histology were characterized. The subjects recorded bleeding patterns daily. Endometrial biopsies were performed during scheduled follow-up visits at 48 and 96 weeks or as needed to evaluate abnormal bleeding. Data were analyzed by intention to treat. Ten and four subjects dropped out of the study from groups I and II, respectively. A total of 575 and 627 treatment cycles were observed in the same respective groups. Vaginal bleeding was observed in 980 cycles: 381 of 575 cycles in group I (66.3%) and 599 of 627 cycles in group II (95.5%). Bleeding onset, duration, and quantity were similar for both groups. The incidence of hyperplasia was 42 and 4% for groups I and II, respectively, over the 96-week study period. All cases of hyperplasia in group I were treated with sequential medroxyprogesterone acetate for 12 weeks, followed by rebiopsy. In ten of 11 cases, the progestin therapy converted the hyperplasia to a normal endometrium. In one case, the endometrium became hyperplastic again at 96 weeks, but reverted to normal with 12 weeks of medroxyprogesterone acetate.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of continuous versus sequential estrogen and progestin therapy in postmenopausal women.

A pilot study was performed comparing the efficacy and safety of continuous versus sequential schedules of the two most commonly prescribed medications for ovarian hormone replacement, conjugated equine estrogens and medroxyprogesterone acetate. Bleeding patterns, endometrial histology, and metabolic parameters were studied in 48 postmenopausal women prospectively randomized to a continuous schedule (daily estrogen and progestin) or a sequential schedule (conjugated estrogen on days 1-25, medroxyprogesterone acetate on days 16-25). Doses studied were 0.625 and 1.25 mg of conjugated estrogens and 10 mg of medroxyprogesterone acetate. Significantly greater bleeding was observed with the 1.25-mg dosage of conjugated estrogens. Bleeding patterns were similar between schedules, with the exception that amenorrhea was more prevalent in the women using the 1.25-mg dosage of estrogen and the continuous progestin schedule. More frequent endometrial atrophy was observed with the continuous schedule, supporting the concept that prolonged use of this schedule may promote amenorrhea in most patients. Both doses and schedules were associated with modest and insignificant increases in high-density lipoprotein cholesterol. Sequential therapy did not prevent the estrogen-induced decrease of low-density lipoprotein cholesterol, whereas the continuous schedule did, particularly with 0.625-mg dosage of conjugated estrogens. Significant increases of triglycerides were also seen with the continuous but not with the sequential schedule. Because of reports that the continuous schedule using the 2.5-mg dosage of medroxyprogesterone acetate does not elicit these actions on circulating lipids, attention should be directed toward examining the long-term effects of this lower dosage given continuously.

Sperm as activating cofactors in HIV sexual transmission.

PIP: Researchers at the University of California at Los Angeles and at the National Institute for Immunology in New Delhi, India conducted parallel laboratory studies which indicate that sperm may augment HIV infectivity. The studies showed that HIV binds easily to sperm. Further, sperm infects target peripheral blood leukocytes (PBLs) proficiently. In addition, sperm binds to HLA-DR molecules which can transduce signals. Similar to what happens when an immobilized anti HLA-DR antibody binds with the surface of HLA-DR which in turn activates HLA-DR expressing cells, sperm binding with HLA-DR also activates HLA-Dr expressing cells. The sperm/HLA-DR binding serves to transduce receptor coupled signals and expands and divides target cells. Target cell activation increases HIV entry and initiates latency. Furthermore new virus replication needs activation. If indeed sperm can activate HLA-DR bearing cells, this may explain both sperm increased HIV infectivity observed for PBLs in vitro and the efficiency of semen for transmitting HIV in vivo. Besides, HLA-DR bearing cells exist in great numbers in the female reproductive tract. In fact, some even express the HIV receptor CD4. These results suggest that sperm play an important role in the microenvironment leading to HIV infection. They also emphasize the significance of spermicide use with condoms to protect against HIV transmission.^ieng