The threshold hypothesis: solving the equation of nurture vs nature in type 1 diabetes

For more than 40 years, the contributions of nurture (i.e. the environment) and nature (i.e. genetics) have been touted for their aetiological importance in type 1 diabetes. Disappointingly, knowledge gains in these areas, while individually successful, have to a large extent occurred in isolation from each other. One reason underlying this divide is the lack of a testable model that simultaneously considers the contributions of genetic and environmental determinants in the formation of this and potentially other disorders that are subject to these variables. To address this void, we have designed a model based on the hypothesis that the aetiological influences of genetics and environment, when evaluated as intersecting and reciprocal trend lines based on odds ratios, result in a method of concurrently evaluating both facets and defining the attributable risk of clinical onset of type 1 diabetes. The model, which we have elected to term the 'threshold hypothesis', also provides a novel means of conceptualising the complex interactions of nurture with nature in type 1 diabetes across various geographical populations.

Abstract 3189: Misclassification of cervical precancer: Impact of a new colposcopy protocol on disease ascertainment and biomarker performance

Introduction: Cytology-based screening for and treatment of cervical precancers has led to substantial reduction of cervical cancer incidence and mortality worldwide. Current screening approaches have limited accuracy, however, and lead to misclassification of cervical precancer at the levels of primary screening, colposcopic evaluation, and histological evaluation. We designed the Biopsy Study to systematically evaluate the extent of misclassification of cervical precancer at colposcopy.

Methods: Previously-untreated women referred to the University of Oklahoma colposcopy clinic for abnormal screening results were enrolled. Before colposcopy, a specimen was taken for liquid-based cytology, HPV genotyping, and biomarker studies. During colposcopy, a digital image of the cervix was taken and annotated for observed lesions and biopsy sites. Up to four colposcopically directed biopsies were taken from distinct lesions; if less than four targeted biopsies were obtained, a random biopsy was added. All biopsies were ranked by severity based on visual impression and evaluated individually in histology. Three cervical cancer screening tests, Pap cytology, HPV DNA testing, and p16/ki67 cytology, were evaluated against disease endpoints based on the most severely appearing biopsy (representing the current clinical standard) and based on the worst histology result from all four biopsies.

Results: To date, more than 450 women have been enrolled in the study; 86% of women had at least three, and 64% had four biopsies taken. For 377 women, a histological diagnosis was available. Forty-one of 377 women (10.8%) had CIN3, 119 (31.6%) had CIN2, 82 (35.3%) had CIN1, and 84 (22.3%) had benign changes or normal results as worst histological result. In 70.7% of women, the precancer was detected in the first biopsy, in 22.0% it was found at the second biopsy and in 7.3% it was detected in the third or fourth biopsies. Cervical cancer screening tests were evaluated in a subset of 241 women. The specificity of HPV DNA, Pap cytology, and p16/ki67 for the detection of CIN2+ increased by 6%, 7.5%, and 11.8%, respectively when the improved gold standard was applied. Meanwhile, the sensitivity of all screening tests was not reduced.

Discussion: Current colposcopy-biopsy protocols have limited sensitivity in detecting prevalent cervical precancer. In our study, we quantified the incremental benefit of taking multiple biopsies to detect cervical precancer. In the interim analysis, adding a second targeted biopsy improved disease detection by over 20%. The improved sensitivity of colposcopy resulted in decreased misclassification of cervical disease and a more accurate evaluation of cervical cancer screening tests.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3189. doi:10.1158/1538-7445.AM2011-3189

A qualitative assessment of perspectives on the inclusion of adolescents in HIV vaccine trials in South Africa

Adolescents are at high risk for HIV acquisition, and thus need to be included in HIV vaccine trials. In preparation for inclusion of adolescents in HIV vaccine trials in an urban community in Cape Town with a high antenatal HIV prevalence, the study assessed the attitudes towards the inclusion of adolescents in HIV vaccine trials. A total of 18 focus group discussions were conducted using a semistructured interview guide. The participants (n = 200) were adolescents, young adults, parents and other key informants. Participants from all groups welcomed the inclusion of adolescents in HIV vaccine trials due to their high-risk status. There were, however, concerns about sexual disinhibition, fear of side-effects, fear of HIV testing and disclosure of HIV status, mistrust of nurses and clinics. The study highlighted a number of ethical and social issues that need to be addressed before the trials.

A narrow and highly significant linkage signal for severe bipolar disorder in the chromosome 5q33 region in Latin American pedigrees

We previously reported linkage of bipolar disorder to 5q33-q34 in families from two closely related population isolates, the Central Valley of Costa Rica (CVCR) and Antioquia, Colombia (CO). Here we present follow up results from fine-scale mapping in large CVCR and CO families segregating severe bipolar disorder, BP-I, and in 343 population trios/duos from CVCR and CO. Employing densely spaced SNPs to fine map the prior linkage peak region increases linkage evidence and clarifies the position of the putative BP-I locus. We performed two-point linkage analysis with 1134 SNPs in an approximately 9 Mb region between markers D5S410 and D5S422. Combining pedigrees from CVCR and CO yields a LOD score of 4.9 at SNP rs10035961. Two other SNPs (rs7721142 and rs1422795) within the same 94 kb region also displayed LOD scores greater than 4. This linkage peak coincides with our prior microsatellite results and suggests a narrowed BP-I susceptibility regions in these families. To investigate if the locus implicated in the familial form of BP-I also contributes to disease risk in the population, we followed up the family results with association analysis in duo and trio samples, obtaining signals within 2 Mb of the peak linkage signal in the pedigrees; rs12523547 and rs267015 (P = 0.00004 and 0.00016, respectively) in the CO sample and rs244960 in the CVCR sample and the combined sample, with P = 0.00032 and 0.00016, respectively. It remains unclear whether these association results reflect the same locus contributing to BP susceptibility within the extended pedigrees.

Cost-effectiveness of rituximab in refractory cold agglutinin disease

Cold haemagglutinin disease (CHAD) is an uncommon condition frequently associated with B-cell lymphoproliferative disorders and is refractory to conventional treatments used in autoimmune haemolytic anaemia. Rituximab has been used in this condition with favourable and lasting responses. Cost has been a major limitation to its use in such indication. We present cost-effectiveness analysis of the use of rituximab in two patients with CHAD. Rituximab successfully controlled haemolysis in both cases of CHAD and was found to be cost-effective through reducing transfusion needs.

Factors associated with teachers’ implementation of HIV/AIDS education in secondary schools in Cape Town, South Africa

This study investigated the factors influencing whether high school teachers implemented HIV/AIDS education. The independent variables included constructs derived from expectancy value theories, teachers' generic dispositions, their training experience, characteristics of their interactive context and the school climate. We conducted a postal survey of 579 teachers responsible for AIDS education in all 193 public high schools in Cape Town. Questionnaires were completed and returned by 324 teachers (56% response rate) from 125 schools. Many teachers (222; 70%) had implemented HIV/AIDS education during 2003, and female teachers were more likely to have implemented than males (74% vs. 58%). The teacher characteristics associated with teaching HIV/AIDS were previous training, self-efficacy, student-centeredness, beliefs about controllability and the outcome of HIV/AIDS education, and their responsibility. The existence of a school HIV/AIDS policy, a climate of equity and fairness, and good school-community relations were the school characteristics associated with teaching HIV/AIDS. These findings demonstrate the value of teacher training and school policy formulation. They also demonstrate the value and importance of interventions that go beyond a sexual health agenda, focussing on broader school development to improve school functioning and school climate.

Downregulation of the inhibitor of apoptosis protein survivin in keratinocytes and endothelial cells in psoriasis skin following infliximab therapy

BACKGROUND

Survivin, an inhibitor of apoptosis protein (IAP), has been implicated in endothelial cell stability, through inhibition of apoptosis and in cell proliferation.

OBJECTIVES

To evaluate the effect of antitumour necrosis factor (TNF)-alpha therapy on survivin expression in psoriasis skin at 0, 2 and 12 weeks after infliximab therapy.

METHODS

Skin biopsies were obtained from 16 patients; 11 also had arthritis with active skin/joint disease. Clinical scores [Psoriasis Area and Severity Index (PASI), involved body surface area (BSA), Disease Activity Score (DAS28) and Health Assessment Questionnaire] were recorded. Inflammatory infiltration and survivin protein expression were examined and graded by immunohistochemical staining, and mRNA levels were determined by real-time polymerase chain reaction.

RESULTS

Survivin mRNA and protein were demonstrated in all baseline lesional biopsies. Survivin mRNA and protein expression was significantly greater in lesional compared with nonlesional baseline skin (P < 0.05). Differential cellular localization of survivin was demonstrated with cytoplasmic survivin protein expression localized to the perivascular/endothelial regions and strong nuclear staining localized in the basal layer of the epidermis. Infliximab produced a dramatic clinical response in skin and joints (P < 0.05), paralleled by significant reduction in the inflammatory infiltrate and survivin protein expression (P < 0.05) which was reflected at the mRNA level where expression was significantly reduced by week 12 (P < 0.01). Survivin protein levels before and after treatment significantly correlated with PASI (r = 0.478, P < 0.05) and BSA scores (r = 0.528, P < 0.024). PASI strongly correlated with BSA (r = 0.949, P < 0.0001) and DAS28 (r = 0.717, P < 0.002) scores.

CONCLUSIONS

Survivin correlates with disease activity in patients with psoriasis and is significantly downregulated following anti-TNF-alpha treatment. Understanding the role of IAPs in cell survival/antiapoptosis and proliferation mechanisms may provide important insights into downstream therapeutic targeting in inflammation.

DNA vaccination with an insulin construct and a chimeric protein binding to both CTLA4 and CD40 ameliorates type 1 diabetes in NOD mice

Type 1 diabetes (T1D), a T-cell-mediated autoimmune disease, could be attributed to many defects in nonobese diabetic (NOD) mice, including deficient expressions of costimulatory molecules that impair antigen presentation. Thus, this deficient antigen presentation may result in a reduced ability to induce a tolerogenic response through negative selection/regulation of autoreactive T cells. Improperly activated T cells seem to be able to induce autoimmune responses causing diabetes. To re-establish tolerance to autoantigens by modulating costimulation, we constructed and tested a new type of DNA vaccine encoding a membrane-bound preproinsulin (mbPPI) and a chimeric gene vector encoding mutant B7.1/CD40L (mB7.1/CD40L) fusion protein. This mutant B7.1 binds CTLA4 but not CD28. We report that young NOD mice immunized with mbPPI along with mB7.1/CD40L DNA vectors significantly reduced diabetes incidence while treatment with CTLA4/IgG1 exacerbated diabetes. In conclusion, the combination of mbPPI and mB7.1/CD40L was able to protect against autoimmunity and diabetes in NOD mice possibly by promoting a more efficient presentation of autoantigen PPI and inducing specific tolerance to PPI by negatively regulating autoreactive T cells.

Improving the accessibility of condoms in South Africa: the role of informal distribution

Lack of access to condoms presents a fundamental barrier to HIV prevention across most of sub-Saharan Africa. One strategy to enhance the accessibility of condoms is to promote their informal distribution outside of health facilities through existing social networks. To investigate the prevalence and practices of informal condom distribution, we administered a questionnaire to individuals procuring condoms at 12 public health facilities in four regions of South Africa. Of the 554 individuals interviewed, 269 (48%) reported either giving or receiving condoms informally in the month before the study. In multivariate analysis, reporting informal condom distribution was associated with increased education, male gender, multiple sex partners and recent condom use. The specific practices involved in giving or receiving condoms differed between males and females, with women more likely to involve family members and men more likely to involve friends. These results indicate that informal condom distribution is surprisingly common among individuals procuring public sector condoms in South Africa, and begin to suggest the gendered nature of informal condom distribution networks. While these findings require confirmation in other populations, the practices of informal condom distribution described here provide an excellent opportunity for enhancing condom accessibility and delivering other interventions for HIV prevention.

Long-term methadone treatment: effect on CD4+ lymphocyte counts and HIV-1 plasma RNA level in patients with HIV infection

The objective was to examine the effect of methadone on CD4+ lymphocyte counts and viral load and to expect to document the safety of methadone maintenance in patients with human immune deficiency syndrome. This is a retrospective chart analysis comparing the trends in CD4+ count and viral load in two populations of 21 human immunodeficiency virus (HIV) infected patients, one on methadone maintenance and a methadone non-using group. Each methadone user was matched with a control methadone non-user that had a similar CD4+ at the beginning of the study. For the CD4+ count we compared the slope of regression for each couple of patients. In 15 patients we also collected the viral load, which was measured at 4-6 monthly intervals. The mean length of follow-up was 811 days for the methadone group and 797 days in the control group. There was no statistical difference in the treatment received by the two groups of patients during the study. The slope of regression of CD4+ count showed a significantly steeper decline in the methadone-using patients compared with the methadone non-users (r= 0.487; p< 0.05). The evolution of the HIV-1 RNA levels was the same during the follow-up of mean 186 months in a few of the patients in each of the two groups. Long-term methadone use was associated with a significantly faster decrease of CD4+ count in HIV-1 affected patients compared with methadone non-users. HIV-1 RNA data were found in too few patients to enable any conclusions about the development of viral load in the two groups.

Evaluation of a video based health education strategy to improve sexually transmitted disease partner notification in South Africa

OBJECTIVES

To evaluate the feasibility and impact of a health education intervention promoting partner notification for sexually transmitted diseases (STDs).

METHODS

The research setting was a busy public health clinic in a rural district in KwaZulu Natal, South Africa. A before/after quantitative study design was used to measure the effect of an audiovisual presentation of a compelling love drama, posters, and pamphlets. Measures collected from all consenting STD index patients during a 6 week pre-intervention (control) phase were compared with those collected during a 6 week intervention phase. A qualitative evaluation assessed whether the intervention accurately portrayed the intended educational messages.

RESULTS

150 index patients (55% female) were interviewed in the control phase and 185 index patients (64% female) in the intervention phase. The intervention phase showed improvements on several measures of self efficacy about notifying casual partners, such as a belief among index patients that a greater proportion of their casual partners would see the importance of seeking treatment as a result of their notification interaction. The rate of contact cards returned per index patient was 0.27 in the intervention phase, compared with 0.20 in the control phase (95% CI for the rate difference: -0.05, 0.17). The qualitative research found that the intervention was thoroughly enjoyed by patients and clinicians, but a fundamental problem with it was that patients received confused messages about the relation between HIV/AIDS and other STDs. This has potentially negative consequences for partner notification.

CONCLUSION

The intervention needs further development, and then could provide a highly acceptable, cost effective model for health education in clinics in developing countries.

The effect of TGF-beta 2 on dentin apposition and hardness in transgenic mice

Transforming growth factor beta, TGF-beta, is expressed during tooth formation and can induce pre-odontoblast differentiation and formation of functional odontoblast-like cells in vitro. In addition, exogenous TGF-beta can increase reparative dentin formation, presumably by acting on odontoblasts. In this study, we examined the tooth phenotype of transgenic mice, in which TGF-beta 2 expression is directed by the osteocalcin promoter. Previous studies have shown that these mice have a bone phenotype that resembles that of human osteoporosis, including the existence of spontaneous fractures. Microhardness testing of the enamel and dentin showed no differences in the molars of these transgenic mice as compared with those of their wild-type littermates. Consistent with the increase in bone mineral apposition rate previously reported in these mice, the dentin apposition rate appeared to be increased in the TGF-beta 2-overexpressing mice. Thus, in teeth, as in bone, TGF-beta 2 appears to stimulate the synthesis and deposition of matrix. Further studies are needed to understand the effect of TGF-beta 2 on distinct mineralized tissues (bone, dentin, and cementum) and to determine whether exogenous TGF-beta 2 may be useful for tooth repair.

A randomized controlled trial assessing the health economics of realtime teledermatology compared with conventional care: an urban versus rural perspective

A randomized controlled trial was carried out to measure the cost-effectiveness of realtime teledermatology compared with conventional outpatient dermatology care for patients from urban and rural areas. One urban and one rural health centre were linked to a regional hospital in Northern Ireland by ISDN at 128 kbit/s. Over two years, 274 patients required a hospital outpatient dermatology referral--126 patients (46%) were randomized to a telemedicine consultation and 148 (54%) to a conventional hospital outpatient consultation. Of those seen by telemedicine, 61% were registered with an urban practice, compared with 71% of those seen conventionally. The clinical outcomes of the two types of consultation were similar--almost half the patients were managed after a single consultation with the dermatologist. The observed marginal cost per patient of the initial realtime teledermatology consultation was 52.85 Pounds for those in urban areas and 59.93 Pounds per patient for those from rural areas. The observed marginal cost of the initial conventional consultation was 47.13 Pounds for urban patients and 48.77 Pounds for rural patients. The total observed costs of teledermatology were higher than the costs of conventional care in both urban and rural areas, mainly because of the fixed equipment costs. Sensitivity analysis using a real-world scenario showed that in urban areas the average costs of the telemedicine and conventional consultations were about equal, while in rural areas the average cost of the telemedicine consultation was less than that of the conventional consultation.