Heterosexual transmission of HIV

3-Hydroxyphthaloyl-β-Lactoglobulin. II. Anti-Human Immunodeficiency Virus Type 1 Activity in in Vitro Environments Relevant to Prevention of Sexual Transmission of the Virus

It is anticipated that the rate of sexual transmission of viruses could be substantially decreased by the use of topical chemical barrier methods. Chemical modification of bovine (β-lactoglobulin (β-LG), the major protein of whey, led to the generation of a potent inhibitor (designated 3HP-β-LG) of human immunodeficiency virus type 1 (HIV-1) infection which was also active against herpesviruses. Compounds intended for topical application to prevent sexual transmission of viruses need to maintain their antiviral activity at pH <<7, corresponding to an acidic vaginal environment, and in the presence of seminal fluid. Results presented here show that the binding of 3HP-β-LG to the CD4 receptor for HIV, involved in the anti-HIV-1 activity of this compound, decreases with decreasing pH. The presence of seminal fluid also decreased the binding of 3HP-β-LG to CD4 and diminished the inhibitory effect of the compound on CD4-gp120 binding. 3HP-β-LG was shown to bind Zn++, and the inhibitory effect of seminal fluid could be substantially diminished by chelating Zn++ with ethylenediaminetetraacetate. Saliva had no effect on 3HP-β-LG binding to CD4 or on its interference with gp120-CD4 binding. The decreased 3HP-β-LG-CD4 binding and the concomitant reduction of gp120-CD4 binding inhibition by 3HP-β-LG at low pH and in the presence of seminal fluid could be compensated for by an increase of the 3HP-β-LG concentration and by adding Zn++ chelators to 3HP-β-LG. These results provide a background for the design of 3HP-β-LG formulations for topical use.

Factors Important to the Prioritization and Development of Successful Topical Microbicides for HIV-1

Significant advancements in topical microbicide development have occurred since the prevention strategy was first described as a means to inhibit the sexual transmission of HIV-1. The lack of clinical efficacy of the first generation microbicide products has focused development attention on specific antiretroviral agents, and these agents have proven partially successful in human clinical trials. With greater understanding of vaginal and rectal virus infection, replication, and dissemination, better microbicide products and delivery strategies should result in products with enhanced potency. However, a variety of development gaps exist which relate to product dosing, formulation and delivery, and pharmacokinetics and pharmacodynamics which must be better understood in order to prioritize microbicide products for clinical development. In vitro, ex vivo, and in vivo models must be optimized with regard to these development gaps in order to put the right product at the right place, at the right time, and at the right concentration for effective inhibition of virus transmission. As the microbicide field continues to evolve, we must harness the knowledge gained from unsuccessful and successful clinical trials and development programs to continuously enhance our preclinical development algorithms.

Vaginal microbicides to prevent human immunodeficiency virus infection in women: perspectives on the female genital tract, sexual maturity and mucosal inflammation

Topically applied vaginal microbicides to protect against human immunodeficiency (HIV) virus infection offer an important female-controlled prevention strategy. Microbicides have been in development for more than 2 decades, and have included various agents that disrupt cellular and microbial membranes (surfactants), restore the natural acidic protective pH of the vagina (acid buffers), and those that interfere with interactions between HIV envelope proteins and cellular receptors (anionic polymers). Although none of these candidate microbicides have shown significant protection against HIV in clinical trials, a topical gel, including the antiretroviral drug tenofovir (TFV) 1% was the first microbicide to be tested to show some protection against HIV infection. This review explores the effect of female genital tract biology and anatomy, mucosal inflammation, and age on the effectiveness of microbicides to prevent HIV infection.

Characterization of nitric oxide-releasing microparticles for the mucosal delivery

For the treatment of female sexual arousal disorder (FSAD), we developed microparticles made of PLGA containing nitric oxide (NO) donor (DETA NONOate) to efficiently deliver NO to vaginal mucosa. The NO-releasing microparticles were prepared by various emulsion methods. SEM and DSC studies were performed to examine the microparticles. The release studies were conducted under various conditions to optimize the loading dose in the microparticles. NO diffusivity through vaginal epithelial cells was evaluated and pharmacological activity of NO-releasing microparticles was examined by assessment of intracellular cGMP level in vaginal cells. Through the modified double emulsion solvent evaporation method (w/o/w(a)), the acid labile DETA NONOate was stabilized during the fabrication process and homogenous morphology and high entrapment efficiency were achieved. DETA NONOate was protected under the acidic conditions of the vagina and NO was released from the microparticles in a controlled manner. A significant amount of NO produced from DETA NONOate penetrated through the vaginal epithelial cells. The intracellular cGMP level increased with the treatment of NO-releasing microparticles in vaginal cells. These findings suggest that NO-releasing microparticles could improve the vaginal blood perfusion and open up the possibilities of novel treatment of FSAD.

Preclinical evaluation of lime juice as a topical microbicide candidate

BACKGROUND

The continued growth of the global HIV epidemic highlights the urgent need to develop novel prevention strategies to reduce HIV transmission. The development of topical microbicides is likely to take a number of years before such a product would be widely available. This has resulted in a call for the rapid introduction of simpler vaginal intervention strategies in the interim period. One suggested practice would be vaginal douching with natural products including lime or lemon juice. Here we present a comprehensive preclinical evaluation of lime juice (LiJ) as a potential intervention strategy against HIV.

RESULTS

Pre-treatment of HIV with LiJ demonstrated direct virucidal activity, with 10% juice inactivating the virus within 5 minutes. However, this activity was significantly reduced in the presence of seminal plasma, where inactivation required maintaining a 1:1 mixture of neat LiJ and seminal plasma for more than 5 minutes. Additionally, LiJ demonstrated both time and dose-dependent toxicity towards cervicovaginal epithelium, where exposure to 50% juice caused 75-90% toxicity within 5 minutes increasing to 95% by 30 minutes. Cervicovaginal epithelial cell monolayers were more susceptible to the effects of LiJ with 8.8% juice causing 50% toxicity after 5 minutes. Reconstructed stratified cervicovaginal epithelium appeared more resilient to LiJ toxicity with 30 minutes exposure to 50% LiJ having little effect on viability. However viability was reduced by 75% and 90% following 60 and 120 minutes exposure. Furthermore, repeat application (several times daily) of 25% LiJ caused 80-90% reduction in viability.

CONCLUSION

These data demonstrate that the virucidal activity of LiJ is severely compromised in the presence of seminal plasma. Potentially, to be effective against HIV in vivo, women would need to apply a volume of neat LiJ equal to that of an ejaculate, and maintain this ratio vaginally for 5-30 minutes after ejaculation. Data presented here suggest that this would have significant adverse effects on the genital mucosa. These data raise serious questions about the plausibility and safety of such a prevention approach.

Lubricants containing N-9 may enhance rectal transmission of HIV and other STIs

It has been shown that men who have sex with men actively seek lubricants that contain nonoxynol-9 (N-9) because they believe that N-9 may help to prevent infection by HIV. However, indirect evidence suggests that N-9 may actually enhance infection. Microscopic examination of rectal lavage and biopsy specimens collected at different time points following rectal application of a lubricant containing 2% N-9 showed rapid exfoliation of the rectal epithelium. Because the rectal epithelium protects target cells in the submucosa from HIV, we conclude that lubricants containing N-9 should be avoided during rectal sex.

Why consider vaginal drug administration?

OBJECTIVE

To review the anatomy and physiology of the vagina, the merits of vaginal drug administration, and the currently available vaginal drug-administration systems.

DESIGN

Review of basic and clinical research.

RESULT(S)

Although clinicians commonly use topically administered drugs in the vagina, this route for systemic drug administration is somewhat novel. Experience with a variety of products demonstrates that the vagina is a highly effective site for drug delivery, particularly in women's health. The vagina is often an ideal route for drug administration because it allows for the administration of lower doses, steady drug levels, and less frequent administration than the oral route. With vaginal drug administration, absorption is unaffected by gastrointestinal disturbances, there is no first-pass effect, and use is discreet. Knowledge of anatomy, physiology, histology, and immunology of the vagina should allow clinicians to reassure their patients concerning this mode of delivery. Greater understanding and experience by clinicians should lead to increased use and acceptance of the vagina as a route for drug administration.

CONCLUSION(S)

The safety and efficacy of vaginal administration have been well established. The vaginal route of drug delivery is acceptable and may even be a preferable route of administration for many drugs, particularly hormones, whether for contraception or postmenopausal estrogen therapy.

Effect of buffers on the properties of microbicidal hydrogels containing monoglyceride as the active ingredient

Hydrogel formulations containing the monoglyceride monocaprin have shown potent microbicidal activity against several sexually transmitted viruses and bacteria. It is recommended that formulations for preventing infection in the vagina have a low pH as the HIV virus is inactivated at low pH. The object of the work was to investigate how incorporation of buffers into the hydrogel formulations affects physicochemical properties and microbicidal activity of the active substance. Two series of gels were formulated using carbomer (Carbopol 934) and sodium carboxymethylcellulose (NaCMC) as gel-forming agents. The presence of buffers in the gels caused a lowering in gel viscosity, with carbomer gels being more sensitive to buffer presence than NaCMC gels. To obtain viscosity similar to that of a gel without buffer, the amount of polymer needs to be increased. An increase in the amount of NaCMC by 60-70% is needed to obtain the same viscosity as in gel without buffers; but for carbomer, the amount of polymer needs to be doubled. It appears that the effect of maleate buffer on NaCMC gel formation is greater than that of the citrate/lactate buffer; but for carbopol gels, the effects of the buffer systems tested on gel viscosity were equal. The virucidal activity of NaCMC gel buffered with citrate/lactate buffer against herpes simplex virus type 1 and HIV was not reduced by the presence of buffer. The results show that the presence of buffers in the hydrogel formulations affects gel viscosity, but the virucidal effect of the active compound, monocaprin, is not diminished.

Development pharmaceutics of microbicide formulations. Part I: preformulation considerations and challenges

Microbicides, the compounds and formulations that can prevent transmission of sexually transmitted diseases (STDs)/HIV are being pursued actively as a promising AIDS intervention. The drug development chain for a topical microbicide differs significantly from that of any systemic or topical compound/formulation regarding to time line, cost, activities, and milestones. This is in part because of the lack of standard in vitro models to assess efficacy, and complex ethical issues in clinical trials of microbicides. Several factors, including changes in the physiology of the cervix and vagina with age and menstrual cycle, intercourse, as well as leakage of the formulation from the vagina may affect their design, development, and performance. Selection and development of optimal microbicide delivery systems (gel/cream, pessary, film, tablet, foam, etc.), their inactive ingredients, manufacturing details, and packaging system are dependent on the properties of active drug, or their preformulation parameters (PP). The PP of the active drug substance needs to be evaluated in initial stages of drug discovery and development so that the most suitable delivery system can be selected. Some PP of microbicide agents include physical state, organoleptic properties (color, odor, appearance, taste, etc.), molecular weight, aqueous solubility, hygroscopicity, acidity/alkalinity, permeability and absorption characteristics, stability in solid/solution state, and inherent bioadhesiveness. Thus, a well-coordinated, planned, and implemented preformulation program can help in not only accelerating microbicide formulation development, but also to minimize unforeseen failures in subsequent stages of the development. The objective of this review is to highlight the significance of PP, suggesting a systematic preformulation program.

Use of mandelic acid condensation polymer (SAMMA), a new antimicrobial contraceptive agent, for vaginal prophylaxis

OBJECTIVE

To assess the contraceptive properties, antimicrobial activity, and safety of mandelic acid condensation polymer (SAMMA).

DESIGN

Experimental study of SAMMA's in vitro and in vivo properties.

SETTING

Academic research laboratories.

PATIENT(S)

Healthy volunteers for semen donation in an academic research environment.

INTERVENTION(S)

Inhibition of sperm function indicators, conception, sexually transmitted infection-causing pathogens (including HIV), and lactobacilli was evaluated. Safety indicators were studied.

MAIN OUTCOME MEASURE(S)

Quantitation of SAMMA's effect on microbial infectivity or multiplication and on sperm function in vitro; evaluation of contraceptive efficacy in vivo; assessment of safety in vitro and in vivo.

RESULT(S)

Mandelic acid condensation polymer is not cytotoxic toward lactobacilli, microbial host cells, and spermatozoa. The compound inhibits hyaluronidase and acrosin, induces sperm acrosomal loss, and is contraceptive in the rabbit model. Mandelic acid condensation polymer prevents infectivity of HIV and herpesviruses 1 and 2 and, to a lesser extent, of Chlamydia trachomatis. It inhibits the multiplication of Neisseria gonorrhoeae. Mandelic acid condensation polymer is not mutagenic, has low acute oral toxicity, and is safe in the rabbit vaginal irritation assay.

CONCLUSION(S)

Mandelic acid condensation polymer inhibits sperm function, is contraceptive, has broad-spectrum antimicrobial activity, and is highly safe. Further development as a microbicide is warranted.

The innate and early immune response to pathogen challenge in the female genital tract and the pivotal role of epithelial cells

The female reproductive tract is immunologically unique in its requirement for tolerance to allogeneic sperm and, in the upper tract, to the conceptus. However, it must also be appropriately protected from, and respond to, a diverse array of sexually transmitted pathogens. Some of these infections can be lethal (e.g. Human Immunodeficiency Virus (HIV), Human Papilloma Virus (HPV)), and others (e.g. Chlamydia trachomatis and Neisseria gonorrhoeae) can have potentially devastating reproductive sequelae. Interactions between a host and a pathogen are complex, diverse and regulated, and are a function of the individual pathogen, and host immunity. Although there is undoubtedly commonality in the mucosal immune response, there is also evidence of a degree of site-specificity in immune mechanisms, dependent upon the function and anatomical location of an organ. In this article, we review the evidence on the pivotal role of epithelial cells in the innate and early immune response to pathogen challenge in female genital tract tissues, and examine the evidence that the 'sterile' upper and the 'non-sterile' lower female genital tract may maintain a different immunological surveillance milieu, and may also respond differentially to pathogen challenge. We also review the unique characteristics, and subsequent ramifications of the acute cervical immune response to C. trachomatis, and discuss how natural antimicrobial mediators of immunity may be utilized to decrease the spread of sexually transmitted infections.

An Update on Vaginal Microbicides

In response to an increasing prevalence of sexually transmitted diseases, especially AIDS, efforts to prevent further infections have been heightened. One of those approaches has been the development of topical microbicidal agents or microbicides. These are compounds designed to protect the body's mucosal surfaces from infection by sexually transmitted disease-causing pathogens. Numerous candidates are currently in preclinical stages; however, only a handful have been tested for safety, and even fewer are ready for clinical efficacy trials. In this update, we describe some of the specific features of microbicide research and development, including preclinical screening algorithms, candidate's ideal properties, examples of compounds presently in the pipeline, and future prospects.

Properties of a new acid-buffering bioadhesive vaginal formulation (ACIDFORM)

Vaginal prophylactic methodology may prevent heterosexual transmission of the HIV and other sexually transmitted disease-causing organisms as well as unplanned pregnancies. A new delivery system (ACIDFORM) was designed with acid-buffering, bioadhesive, and viscosity-retaining properties to (1) maintain the acidic vaginal milieu (the low pH inactivates many pathogens and spermatozoa), (2) form a protective layer over the vaginal/cervical epithelium (minimizing contact with pathogenic organisms), and (3) provide long-term vaginal retention. A Phase I clinical study with ACIDFORM provided initial information about its safety and showed the formation of a layer over the vaginal/cervical epithelium [1; Amaral et al., Contraception 1999;60:361-6]. To study the properties of the gel (without active ingredient) in more detail, ACIDFORM's acid-buffering, bioadhesive, viscosity-retaining, and spermicidal properties were compared in vitro to marketed formulations, and its long-term stability was assessed. ACIDFORM, either when titrated with NaOH or when mixed directly with semen, is highly acid buffering and much more effective than Aci-Jel, a commercial acid-buffering vaginal product. ACIDFORM adheres well to two model membranes (excised sheep vagina and cellophane) and is more bioadhesive than Conceptrol, Advantage S, Replens, Aci-Jel, and K-Y jelly. On dilution, ACIDFORM also retains its viscosity better than these marketed products. ACIDFORM is spermicidal and is stable for at least 2 years. These results suggest that ACIDFORM has advantages over presently marketed vaginal delivery systems. The gel may either be useful by itself as an antimicrobial contraceptive product or as a formulation vehicle for an active ingredient with antimicrobial and/or contraceptive properties.

Bacterial vaginosis in pregnancy

Bacterial vaginosis is a clinical condition caused by replacement of the normal hydrogen peroxide producing Lactobacillus sp. in the vagina with high concentrations of characteristic sets of aerobic and anaerobic bacteria. Bacterial vaginosis is the most prevalent cause of vaginal discharge or malodor, although 50 percent of women who meet the criteria for this condition are asymptomatic. Bacterial vaginosis is reported in 10 to 41 percent of women, and new evidence has shown association with maternal and fetal morbidity. Studies have shown that spontaneous abortion, preterm labor, premature birth, preterm premature rupture of the membranes, amniotic fluid infection, postpartum endometritis, and postcesarean wound infections are increased because of infection with bacterial vaginosis during pregnancy. Clinical trials demonstrated important reductions in many of these adverse events with appropriate screening and antimicrobial treatment protocols. New low-cost, diagnostic, point-of-care screening tools are available for rapid screening of patients, affording the physician the opportunity to potentially make a dramatic clinical and cost impact in preventing preterm birth and the costly sequelae of prematurity. Practicing physicians need to be aware of current guidelines for screening and treating pregnant patients for bacterial vaginosis. The authors recommend that all pregnant women be screened and treated with the Centers for Disease Control and Prevention (CDC-P) recommended oral regimens early in pregnancy. Each treated women should be evaluated for "test of cure" 1 month after treatment. Mothers likely to benefit from "screen and treat" approaches include 1) those with the highest concentrations of genital anaerobes and mycoplasmas, 2) women with prior preterm birth or who have low body mass (BMI < 19.8 kg/m2), 3) those with evidence of endometritis before pregnancy, and 4) those who are treated with oral agents effective for both presumed intrauterine mycoplasmas and other bacterial vaginosis flora (i.e., oral clindamycin or erythromycin and metronidazole).

Is There a Protective Role for Vaginal Flora?

The notion of a protective vaginal flora is relatively new. Resident flora manifest colonization resistance to prevent or reduce the likelihood of exogenous microorganisms, viruses, bacteria, yeast, or parasites becoming established in the lower genital tract of women following sexual (HIV, Neisseria gonorrhoeae, Escherichia coli, Candida albicans, Trichomonas vaginalis) or nonsexual (uropathogenic E. coli) transmission. The concept of preserving or reestablishing protective flora has been hastened by several factors, including the potential widespread use of vaginal microbicides, the increased heterosexual spread of HIV, and the imminent availability of exogenous Lactobacillus species probiotic therapy.

Changing testicular histology in AIDS: its implication for sexual transmission of HIV

OBJECTIVES

The understanding of testicular histology in acquired immunodeficiency syndrome (AIDS) is essential, because the sexual route is one of the main means of transmission of the human immunodeficiency virus, which is localized primarily in the germ cells of the testes. It is important to determine whether any changes have occurred in the testicular histologic patterns in the course of the AIDS epidemic.

METHODS

One hundred forty testicular specimens were available from AIDS autopsies during the AIDS epidemic (1981 to 1998). The epidemic was divided into pre-zidovudine (pre-AZT) therapy (1981 to 1987) and antiviral therapy (1988 to 1998) periods; the latter period was further subdivided on the basis of the particular treatment used. Testicular histology was evaluated and correlated with patient age, CD4 T-cell counts, and pathologic findings in other parts of the body.

RESULTS

Testicular histologic findings were categorized into three groups: hypospermatogenesis (group S), spermatogenic arrest (group A), and Sertoli cell only (group O). The percentage of AIDS patients with group S histologic findings remained constant throughout the study period: 26% in the pre-AZT and 28% in the antiviral therapy periods. However, there was a reversal in the percentages of patients in groups A and O: group A decreased from 48% (pre-AZT) to 28% (antiviral) and group O increased from 26% (pre-AZT) to 44% (antiviral). There was no correlation between testicular histologic results and patient age or CD4 count. Opportunistic infections and testicular neoplasms were also identified.

CONCLUSIONS

This study demonstrates that current therapy and prolongation of survival in AIDS patients are associated with a shift in the histologic findings of testes toward a more pronounced loss of germ cells. However, 28% of patients still show significant spermatogenesis at the time of death from AIDS and this subgroup cannot be identified by age or CD4 T-cell counts. The presence of large numbers of residual germ cells in these patients suggests that they may continue to be infectious throughout their disease course.

HIV infection and disturbances of vaginal flora during pregnancy

Disturbances of vaginal flora are common among women of reproductive age. In areas of sub-Saharan Africa where the prevalence of HIV is high, the frequency of bacterial vaginosis (BV) is also high. In this study, we assessed the association of BV and other disturbances of vaginal flora with prevalent HIV infection in two cross-sectional studies among pregnant women in urban Malawi. The prevalence of HIV-1 was 23% in 1990 and 30% in 1993. Overall, 30% of the women had BV, 59% had mild or moderate disturbance of vaginal flora, and only 11% had normal vaginal flora. Increasing prevalence of HIV was significantly associated with increasing severity of disturbance of vaginal flora (p < .00001, chi2 trend test). This trend of increased prevalence persisted after controlling for concurrent sexually transmitted diseases (STDs), sexual activity, and socioeconomic factors. After multivariate adjustment for potential confounders, the odds ratio for the association of BV with prevalent HIV infection was 3.0 (95% confidence interval [CI], 2.4-3.8), that of moderate vaginal disturbance with HIV infection was 2.2 (95% CI, 1.7-2.8), and that of mild vaginal disturbance with HIV infection was 1.6 (95% CI, 1.3-2.1). Among women with BV, HIV infection was higher among younger women than older, implying more recent infection. Although these studies were cross-sectional, our data suggest that BV could be associated with increased susceptibility to HIV infection.

Bacterial vaginosis and disturbances of vaginal flora: association with increased acquisition of HIV

BACKGROUND

Cross-sectional studies suggest an association between bacterial vaginosis (BV) and HIV-1 infection. However, an assessment of a temporal effect was not possible.

OBJECTIVES

To determine the association of BV and other disturbances of vaginal flora with HIV seroconversion among pregnant and postnatal women in Malawi, Africa.

DESIGN

Longitudinal follow-up of pregnant and postpartum women.

METHODS

Women attending their first antenatal care visit were screened for HIV after counselling and obtaining informed consent. HIV-seronegative women were enrolled and followed during pregnancy and after delivery. These women were again tested for HIV at delivery and at 6-monthly visits postnatally. Clinical examinations and collection of laboratory specimens (for BV and sexually transmitted diseases) were conducted at screening and at the postnatal 6-monthly visits. The diagnosis of BV was based on clinical criteria. Associations of BV and other risk factors with HIV seroconversion, were examined using contingency tables and multiple logistic regression analyses on antenatal data, and Kaplan-Meier proportional hazards analyses on postnatal data.

RESULTS

Among 1196 HIV-seronegative women who were followed antenatally for a median of 3.4 months, 27 women seroconverted by time of delivery. Postnatally, 97 seroconversions occurred among 1169 seronegative women who were followed for a median of 2.5 years. Bacterial vaginosis was significantly associated with antenatal HIV seroconversion (adjusted odds ratio = 3.7) and postnatal HIV seroconversion (adjusted rate ratio = 2.3). There was a significant trend of increased risk of HIV seroconversion with increasing severity of vaginal disturbance among both antenatal and postnatal women. The approximate attributable risk of BV alone was 23% for antenatal HIV seroconversions and 14% for postnatal seroconversions.

CONCLUSIONS

This prospective study suggests that progressively greater disturbances of vaginal flora, increase HIV acquisition during pregnancy and postnatally. The screening and treating of women with BV could restore normal flora and reduce their susceptibility to HIV.

In vivo semen-associated pH neutralization of cervicovaginal secretions

Physiological cervicovaginal acidity can partly inactivate human immunodeficiency virus (HIV). Basic semen components should be able to partially neutralize in vivo cervicovaginal pH. The goals of the study were to evaluate the relationship between cervicovaginal pH and presence of semen components in sexually active African women and to assess whether vaginal douching with water performed just after sexual intercourse could significantly reduce semen components and restore physiological cervicovaginal pH. Cervicovaginal secretion (CVS) from 56 heterosexual African women (19 to 45 years old), living in Bangui, Central African Republic, were evaluated for pH, semen components (prostatic acid phosphatase [PAP] and prostatic specific antigen [PSA]), cellularity, and hemoglobin at inclusion and after vaginal douching with 100 ml of water by using a bock. Before douching, semen components were found in 46 of 56 CVS (82%). The mean vaginal pH was 5.2 (range, 3.6 to 7.7), and concentrations of both PAP and PSA correlated positively and strongly with cervicovaginal pH (P < 0.001). After douching, semen components were found in 35 of 56 CVS (62%) (P = 0.03). Cervicovaginal PAP and PSA levels were significantly decreased (respectively, P < 0.0001 and P < 0.01; PAP, -72%; PSA, -87%), as was the total cell count (-60%; P < 0.0001). Furthermore, in CVS previously positive for both PAP and PSA, the mean vaginal pH was significantly decreased (6.5 versus 5.3, P < 0.01); no genital bleeding was observed. Frequent persistence of semen in CVS from heterosexually active African women leads to a shift from acidity to neutrality that could favor male to female HIV transmission. Vaginal douching provides significant elimination of semen after sexual intercourse; it should be considered for study as a supplementary means for the prevention of heterosexual HIV transmission.

Vaginal pH neutralization by semen as a cofactor of HIV transmission

OBJECTIVE: To explain the high frequency of heterosexual transmission of AIDS in subSaharan countries, by investigating post-intercourse semen retention in the vagina for local pH neutralization as a possible interference factor with acidic inactivation of HIV virions. METHODS: Two semen markers, prostate-specific antigen and prostatic acid phosphatase, were measured and compared with the pH values in the vaginal washes of 69 women from the Central African Republic. The capacity of semen to raise the vaginal pH was also investigated in vitro. RESULTS: Of 61 non-menstrual specimens, 74% contained at least one semen marker. The specimens with high levels of markers (group I) displayed an almost neutral pH (median 6.1), at variance with the semen-free group II (median: 3.7, P<0.003), and with group III (median: 4.0) corresponding to low or past semen retention. The in vitro study confirmed the high neutralization capacity of semen. CONCLUSIONS: It is expected that post-intercourse neutralization of pH will both favor male-to-female transmission and prevent the acidity-associated loss of infectivity of the female-derived virions, thus allowing female-to-male transmission during further sexual contact.

HIV infection and vaginal douching in central Africa

OBJECTIVE

To determine whether vaginal douching is associated with HIV infection.

METHODS

A total of 397 female patients who attended the referral clinic for sexually transmitted diseases in Bangui, Central African Republic, from August 1994 to February 1995, were interviewed regarding sexual behavior, sexual history, and vaginal douching during the previous 3 years. Pelvic examinations were conducted and vaginal and cervical fluids evaluated for genital infections. Blood was drawn for HIV and syphilis serologic testing.

RESULTS

The seroprevalence of HIV infection in the study population was 34%. Twenty-one per cent of the 115 HIV-seropositive women had a consistent practice of douching with commercial antiseptics versus 35% of the 223 HIV-seronegative women [odds ratio (OR), 0.6; 95% confidence interval (CI), 0.4-0.9; after adjusting for lifetime number of sexual partners, marital status, and condom use]. In contrast, a higher percentage of HIV-seropositive than HIV-seronegative women had a consistent practice of douching with a non-commercial preparation (14.8 versus 6.7%; adjusted OR, 1.7; 95% CI, 1.0-3.0).

CONCLUSION

Our results suggest that vaginal douching with non-commercial preparations is associated with an increased prevalence of HIV, whereas douching with commercial antiseptic preparations was associated with a lower prevalence of HIV. The findings from this cross-sectional survey require confirmation in prospective studies.

Women, contraception and STDs including HIV

It is estimated that eight million women are infected with the human immunodeficiency virus (HIV) worldwide. Heterosexual transmission is the predominant mode of HIV transmission on a global basis and is becoming increasingly important in the Western world. Women have long used contraceptives as a means of protection against an unwanted pregnancy, some of which may also protect against sexually transmitted disease (STD) including HIV. We review the relationship between contraceptive methods and STD acquisition and transmission; HIV acquisition and transmission; and the implications of contraceptive use, particularly regarding disease progression, in those women who are already infected with the virus. It is important for all women that protection against both unwanted pregnancy and HIV acquisition and transmission are considered together and not in isolation as nowhere is the argument for a broad based multi-disciplinary approach more cogent.

Lack of evidence for transmission of human immunodeficiency virus through vaginal intercourse

Research in determining risks for human immunodeficiency virus (HIV) transmission is confounded by many issues. They include lack of clarity or specificity in terminology used, respondents misunderstanding of questions, and lying. The base rate of lying (or social desirability responding) by itself is sufficient to account for the small percentage of Americans and Europeans claiming "heterosexual" transmission from partners not known to be intravenous drug users. This study integrates the physiological and epidemiological data on risk factors for HIV transmission with the psychological literature on the frequency of anal intercourse and of lying (in this case to researchers and clinicians about risk factors). When these factors are considered, intravenous and anal activities remain the only clear vectors for HIV transmission. Research suggesting that spermicidals are more effective at inactivating HIV than condoms are at physically containing HIV is also noted.