Tests of Buffergel for contraception and prevention of sexually transmitted diseases in animal models.

BACKGROUND: BufferGel is a novel spermicidal and microbicidal gel formulated to maintain the natural protective acidity of the vagina by acidifying semen, which otherwise alkalinizes the vagina. GOAL: To test the efficacy of BufferGel for preventing sexually transmitted infections and pregnancy in animal models. STUDY DESIGN: Animals were challenged with pathogens or sperm after pretreatment with both test and control agents, or after no pretreatment, then evaluated for infection or pregnancy using standard methods. RESULTS: BufferGel provided significant contraceptive efficacy in the rabbit, and significant protection against vaginal and rectal transmission of herpes simplex virus type 2 (HSV-2) in the mouse, vaginal transmission of Chlamydia trachomatis in the mouse, and skin transmission of cottontail rabbit papillomavirus in the rabbit. It did not protect against vaginal transmission of Neisseria gonorrhoeae in the mouse. CONCLUSIONS: The protective efficacy of BufferGel in five of the six animal models suggests that this microbicide warrants clinical evaluation for both contraception and disease prevention.

Controlled atmosphere stunning of poultry.

For more than 20 yr Stork PMT has carried out a lot of research into stunning and killing of poultry with electrical and mechanical methods and by applying gas mixtures. For the past 3 yr, research was carried out under the European umbrellas (AIR and EUREKA) together with BOC, The Spelderholt, CIVO, and Bristol University. This research program involved tests on broiler stunning or killing with various gas mixtures. The effect on meat quality, bleeding, and plucking was studied, as well as the use of gas as a humane way of killing broilers. The study of meat quality was based on tenderness tests conducted on the shear force principle, meat color, and drip and cooking losses. The percentage of blood loss in bleeding, blood spots, and the amount of blood in the veins in relation to the gas mixtures and time of hanging were measured. The effect of gas killing on the plucking characteristics was studied by determining the feather release force and product handling. The behavior of the birds, reflexes, the onset of convulsions, electroencephalograms, and evoked responses were studied in relation to the humanness of gas killing. Anoxia generated through argon or a mixture of argon and carbon dioxide or hypercapnic hypoxia seems to be very promising. The tests revealed that meat tenderness and drip losses will improve. The blood spots, especially those on the thighs and breasts caused by stunning and hanging, disappear altogether. It also appeared that animal welfare will be drastically improved. From a technological point of view, broiler killing in a controlled gas atmosphere is considered to be the optimal process. However, successful introduction of the process requires legislative changes and poultry processors must be made aware of its economic benefits.

Contraceptive testing of vaginal agents in rabbits.

Development of new vaginal products, such as microbiocides and contraceptives, requires in vivo testing of their effect on fertility. Rabbits, unlike smaller laboratory animals such as rats and mice, which inseminate in the uterus, inseminate vaginally and thus are valuable as animal models for testing vaginal agents for contraceptive effects. Rabbits are inexpensive and easy to handle compared to nonhuman primates, and have frequently been used for testing the effects of vaginal agents on fertility. We review the pertinent literature and report findings that provide guidance for effectively using and improving the rabbit contraceptive model in testing new vaginal products.

Contraceptive effect of sperm-agglutinating monoclonal antibodies in rabbits.

Immune infertility in humans correlates clinically with the presence of anti-sperm antibodies that trap (agglutinate) sperm in semen and cervical mucus. To test whether sperm-agglutinating antibodies can be effective contraceptive agents, several mouse anti-rabbit sperm (MARS) sperm-agglutinating monoclonal antibodies (mAbs) were developed that rapidly and completely agglutinate sperm: MARS-M3 (IgM), MARS-G16 (IgG3), and MARS-G17 (IgG3). Contraceptive efficacy of these mAbs was tested by mixing the mAb with 0.1 ml semen (approximately 1/5 of a whole ejaculate) immediately before artificially inseminating rabbits paracervically. This paracervical dose of semen provided a rigorous test since it delivered several thousand times more fertilizing doses than does a human ejaculate. All of the mAbs were contraceptively effective, and MARS-G16 reduced the number of fetuses per animal by 88% and 95% with doses of 150 microg and 2 mg, respectively. The contraceptive efficacy of the MARS mAbs in the rabbit suggests that human sperm-agglutinating mAbs may be effective agents for vaginal contraception in humans.

Passive immunization of the vagina protects mice against vaginal transmission of genital herpes infections.

Vaginal application of human herpes simplex virus (HSV) antiserum, complement-inactivated antiserum, or IgG purified from antiserum protected mice (P < .001, P < .001, and P < .01, respectively) from visible signs of genital HSV-2 infection after subsequent vaginal inoculation with HSV-2 (10 ID50). Vaginal application of an anti-HSV-2 monoclonal antibody (MAb III-174) also protected mice against infection. This MAb, a neutralizing mouse IgG2A against glycoprotein D, prevented infection as determined by viral shedding from the vagina (P < .05), blocked 50% of visible signs of genital herpes infection at a vaginal dose of approximately 10 ng, and blocked 100% of visible signs of infection at a vaginal dose of 1 microgram (P < .001). These results suggest that vaginal applications of anti-HSV antibodies may help prevent sexual transmission of genital herpes infection.

Nonoxynol-9 protects mice against vaginal transmission of genital herpes infections.

A vaginal application of a commercially available contraceptive jelly containing nonoxynol-9 (N9) prevented vaginal transmission of herpes simplex virus type 2 (HSV-2) infections in the mouse. When N9 jelly was delivered to the vagina with the virus inoculum, 20 s before inoculum, or 5 min before inoculum, mice were completely protected from visible infection (P < .001). Protection lasted for at least 30 min (P < .03), and significant protection occurred even when the N9 jelly was delivered 15 min after the HSV-2 inoculum (P < .05). These results are consistent with results of studies using N9 products in other animal models and suggest that N9-based contraceptive products can provide significant protection against vaginal transmission of enveloped virus infections in animals.