Isolation and sequence analysis of the genomic DNA fragment encoding an aspartic proteinase inhibitor homologue from potato (Solanum tuberosum L.)

A genomic DNA clone encoding an aspartic proteinase inhibitor of potato was isolated from a lambda EMBL3 phage library using the aspartic proteinase inhibitor cDNA as a hybridization probe. The gene has all characteristic sequences normally found in eucaryotic genes. Typical CAAT and TATA box sequences were found in the 5-upstream region. In this part are also two putative regulatory AGGA box sequences located. In the genomic sequence there are no intron sequences interrupting the coding region. An open reading frame of the gene encodes a precursor protein of 217 amino acids which shows high percent identity with the aspartic proteinase inhibitor cDNA.     

Immune Activation in the Female Genital Tract: Expression Profiles of Soluble Proteins in Women at High Risk for HIV Infection

Soluble cervicovaginal biomarkers of inflammation, immune activation and risk of HIV acquisition are needed to reliably assess the safety of new biomedical prevention strategies including vaccines and microbicides. However, a fuller understanding of expression profiles in women at high risk for HIV infection is crucial to the effective use of these potential biomarkers in Phase 3 trial settings. We have measured 45 soluble proteins and peptides in cervicovaginal lavage samples from 100 HIV negative women at high risk for HIV infection. Women were followed over one menstrual cycle to investigate modulation by hormonal contraception, menstrual cycle phase, recent sexual exposure and intravaginal practices. Women using injectable DMPA had increased concentration of several soluble proteins of the innate and adaptive immune system, including IL-1α, IL-1β, IL-2, MIP-1β, IP-10, IL-8, TGF-β, HBD4, IgA, IgG1, and IgG2. Women using combined oral contraceptives had a similar signature. There were differences in concentrations among samples from post-ovulation compared to pre-ovulation, notably increased immunoglobulins. Increased prostate-specific antigen, indicative of recent sexual exposure, was correlated with increased IL-6, MCP-1, and SLPI, and decreased GM-CSF and HBD3. The identified signature profiles may prove critical in evaluating the potential safety and impact on risk of HIV acquisition of different biomedical intervention strategies.     

Rapid increase in prevalence of male circumcision in rural Tanzania in the absence of a promotional campaign

Objectives

To estimate the prevalence of circumcision among young men in rural Mwanza, North-Western Tanzania, and document trends in circumcision prevalence over time. To investigate associations of circumcision with socio-demographic characteristics, reported sexual behaviours and sexually transmitted infections (STIs).

Design

A cross-sectional survey in communities which had previously participated in a cluster-randomized trial of an adolescent sexual health intervention that did not include male circumcision in 20 rural communities.

Methods

In 2007/08, 7300 young men (age 16–23 years) were interviewed and examined by a clinician. The prevalence of circumcision by age was compared with data collected during the trial in 1998–2002. Odds ratios (OR) and 95% confidence intervals (CI) for the association of circumcision with socio-demographic characteristics, reported sexual behaviours and with HIV and other STIs were estimated using multivariable conditional logistic regression.

Results

The prevalence of male circumcision was 40.6%, and age-specific prevalence had more than doubled since 2001/2002. Circumcised men reported less risky sexual behaviours, being more likely to report having ever used a condom (adjusted OR = 2.62, 95%CI:2.32–2.95). Men circumcised before sexual debut were at reduced risk of being HIV seropositive compared with non-circumcised men (adjusted OR = 0.50, 95%CI:0.25–0.97), and also had reduced risks of HSV-2 infection and genital ulcer syndrome in the past 12 months compared with non-circumcised men.

Conclusions

There was a steep increase in circumcision prevalence between 2001/02 and 2007/08 in the absence of a promotional campaign. Circumcised men reported safer sexual practices than non-circumcised men and had lower prevalence of HIV and HSV-2 infection.     

The long-term impact of the MEMA kwa Vijana adolescent sexual and reproductive health intervention: effect of dose and time since intervention exposure

Background

Despite recent decreases in HIV incidence in many sub-Saharan African countries, there is little evidence that specific behavioural interventions have led to a reduction in HIV among young people. Further and wider-scale decreases in HIV require better understanding of when behaviour change occurs and why. The MEMA kwa Vijana adolescent sexual and reproductive health intervention has been implemented in rural Mwanza, Tanzania since 1999. A long-term evaluation in 2007/8 found that the intervention improved knowledge, attitudes to sex and some reported risk behaviours, but not HIV or HSV2 prevalence. The aim of this paper was to assess the differential impact of the intervention according to gender, age, marital status, number of years of exposure and time since last exposure to the intervention.

Methods

In 2007, a cross-sectional survey was conducted in the 20 trial communities among 13,814 young people (15–30 yrs) who had attended intervention or comparison schools between 1999 and 2002. Outcomes for which the intervention had an impact in 2001 or 2007 were included in this subgroup analysis. Data were analysed using cluster-level methods for stratified cluster-randomised trials, using interaction tests to determine if intervention impact differed by subgroup.

Results

Taking into account multiplicity of testing, concurrence with a priori hypotheses and consistency within the results no strong effect-modifiers emerged. Impact on pregnancy knowledge and reported attitudes to sex increased with years of exposure to high-quality intervention.

Conclusions

The desirable long-term impact of the MEMA kwa Vijana intervention did not vary greatly according to the subgroups examined. This suggests that the intervention can have an impact on a broad cross-section of young people in rural Mwanza.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00248469","term_id":"NCT00248469"}}NCT00248469     

HIV Infection among Young People in Northwest Tanzania: The Role of Biological,Behavioural and Socio-Demographic Risk Factors

Background

Young people are at high risk of HIV and developing appropriate prevention programmes requires an understanding of the risk factors for HIV in this age group. We investigated factors associated with HIV among participants aged 15–30 years in a 2007–8 cross-sectional survey nested within a community-randomised trial of the MEMA kwa Vijana intervention in 20 rural communities in northwest Tanzania.

Methods

We analysed data for 7259(53%) males and 6476(47%) females. Using a proximate-determinant conceptual framework and conditional logistic regression, we obtained sex-specific Odds Ratios (ORs) for the association of HIV infection with socio-demographic, knowledge, behavioural and biological factors.

Results

HSV-2 infection was strongly associated with HIV infection (females: adjOR 4.4, 95%CI 3.2–6.1; males: adjOR 4.2, 95%CI 2.8–6.2). Several socio-demographic factors (such as age, marital status and mobility), behavioural factors (condom use, number and type of sexual partnerships) and biological factors (blood transfusion, lifetime pregnancies, genital ulcers, Neisseria gonorrhoeae) were also associated with HIV infection. Among females, lifetime sexual partners (linear trend, p<0.001), ≥2 partners in the past year (adjOR 2.0, 95%CI 1.4–2.8), ≥2 new partners in the past year (adjOR 1.9 95%CI 1.2, 3.3) and concurrent partners in the past year (adjOR 1.6 95%CI 1.1, 2.4) were all associated with HIV infection.

Conclusions

Efforts must be intensified to find effective interventions to reduce HSV-2. Effective behavioural interventions focusing on reducing the number of sexual partnerships and risk behaviour within partnerships are also needed. An increase in risky sexual behaviour may occur following marriage dissolution or when a young woman travels outside of her community and interventions addressing the needs of these subgroups of vulnerable women may be important.

Trial Registration

ClinicalTrial.gov {"type":"clinical-trial","attrs":{"text":"NCT00248469","term_id":"NCT00248469"}}NCT00248469.     

Uptake of Voluntary Counselling and Testing among Young People Participating in an HIV Prevention Trial: Comparison of Opt-Out and Opt-In Strategies

Background

HIV voluntary counselling and testing (VCT) is an integral component of HIV prevention and treatment programmes. However, testing coverage in sub-Saharan Africa is still low, particularly among young people. As treatment becomes more widely available, strategies to expand VCT coverage are critically important. We compare VCT uptake using two delivery strategies (opt-in and opt-out) within the MEMA kwa Vijana trial in 20 communities in northwest Tanzania.

Methods

We analysed data from 12,590 young persons (median (IQR) age 22 years (20–23)) to assess the effect of delivery strategy on VCT uptake. Ten communities used an opt-in approach and 10 used opt-out, balanced across intervention and control. Conditional logistic regression was used to examine factors associated with uptake within each strategy.

Results

VCT uptake was significantly higher with the opt-out approach (90.9% vs 60.5%, prevalence ratio = 1.51, CI = 1.41–1.62). Among females, uptake in the opt-out approach was associated with decreased knowledge of HIV acquisition, sex with a casual partner, and being HSV-2 seronegative; among males, uptake was associated with lower education and increasing lifetime partners. In contrast, uptake using the opt-in approach varied by ethnic group, religion and marital status, and increased with increasing knowledge of STI acquisition (males) or pregnancy prevention (females).

Conclusion

VCT uptake among young people was extremely high when offered an opt-out strategy. Sociodemographic and knowledge factors affected uptake in different ways depending on delivery strategy. Increased knowledge may increase young persons'' self-efficacy, which may have a different impact on testing uptake, depending on the approach used.     

Long-Term Biological and Behavioural Impact of an Adolescent Sexual Health Intervention in Tanzania: Follow-up Survey of the Community-Based MEMA kwa Vijana Trial

Background

The ability of specific behaviour-change interventions to reduce HIV infection in young people remains questionable. Since January 1999, an adolescent sexual and reproductive health (SRH) intervention has been implemented in ten randomly chosen intervention communities in rural Tanzania, within a community randomised trial (see below; {"type":"clinical-trial","attrs":{"text":"NCT00248469","term_id":"NCT00248469"}}NCT00248469). The intervention consisted of teacher-led, peer-assisted in-school education, youth-friendly health services, community activities, and youth condom promotion and distribution. Process evaluation in 1999–2002 showed high intervention quality and coverage. A 2001/2 intervention impact evaluation showed no impact on the primary outcomes of HIV seroincidence and herpes simplex virus type 2 (HSV-2) seroprevalence but found substantial improvements in SRH knowledge, reported attitudes, and some reported sexual behaviours. It was postulated that the impact on “upstream” knowledge, attitude, and reported behaviour outcomes seen at the 3-year follow-up would, in the longer term, lead to a reduction in HIV and HSV-2 infection rates and other biological outcomes. A further impact evaluation survey in 2007/8 (∼9 years post-intervention) tested this hypothesis.

Methods and Findings

This is a cross-sectional survey (June 2007 through July 2008) of 13,814 young people aged 15–30 y who had attended trial schools during the first phase of the MEMA kwa Vijana intervention trial (1999–2002). Prevalences of the primary outcomes HIV and HSV-2 were 1.8% and 25.9% in males and 4.0% and 41.4% in females, respectively. The intervention did not significantly reduce risk of HIV (males adjusted prevalence ratio [aPR] 0.91, 95%CI 0.50–1.65; females aPR 1.07, 95%CI 0.68–1.67) or HSV-2 (males aPR 0.94, 95%CI 0.77–1.15; females aPR 0.96, 95%CI 0.87–1.06). The intervention was associated with a reduction in the proportion of males reporting more than four sexual partners in their lifetime (aPR 0.87, 95%CI 0.78–0.97) and an increase in reported condom use at last sex with a non-regular partner among females (aPR 1.34, 95%CI 1.07–1.69). There was a clear and consistent beneficial impact on knowledge, but no significant impact on reported attitudes to sexual risk, reported pregnancies, or other reported sexual behaviours. The study population was likely to have been, on average, at lower risk of HIV and other sexually transmitted infections compared to other rural populations, as only youth who had reached year five of primary school were eligible.

Conclusions

SRH knowledge can be improved and retained long-term, but this intervention had only a limited effect on reported behaviour and no significant effect on HIV/STI prevalence. Youth interventions integrated within intensive, community-wide risk reduction programmes may be more successful and should be evaluated.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00248469","term_id":"NCT00248469"}}NCT00248469 Please see later in the article for the Editors'' Summary