Qualitative difference between the cytotoxic T lymphocyte responses to melanocyte antigens in melanoma and vitiligo

Vitiligo is a skin disorder characterized by depigmented macules secondary to melanocyte loss. An unusual facet is its relation to melanoma: cytotoxic T lymphocytes directed to melanocyte antigens are found in both conditions and imply a breakdown of tolerance, yet the resulting immune reaction is the opposite. The mechanisms at the basis of these opposite effects are not known. Here, we performed a direct comparison of whole melanocyte-specific T cell populations in the two diseases. We demonstrate that neither precursor frequencies of Melan-A/MART-1-specific T lymphocytes nor their status of activation differ significantly. However, by using a tetramer-based T cell receptor down-regulation assay, we documented a higher affinity of vitiligo T cells. We calculated that the peptide concentration required for 50% of maximal receptor down-regulation differed by 6.5-fold between the two diseases. Moreover, only vitiligo T cells were capable of efficient receptor down-regulation and IFN-gamma production in response to HLA-matched melanoma cells, suggesting that this difference in receptor affinity is physiologically relevant. The differences in receptor affinity and tumor reactivity were confirmed by analyzing Melan-A/MART-1-specific clones established from the two diseases. Our results suggest that the quality, and not the quantity, of the melanocyte-specific cytotoxic responses differs between the two pathologies.     

Risk factors for pneumonia in urban-dwelling HIV-infected women: a case-control study in Nairobi,Kenya

In sub-Saharan Africa, respiratory tract infections (RTI) are the leading cause of serious morbidity and mortality in HIV-infected persons. This study sought to investigate demographic, socioeconomic, and environmental risk factors for pneumonia in a cohort of HIV-infected women. The authors performed a nested case-control study in a cohort of HIV-1-infected adults followed in Nairobi, Kenya. Thirty-nine women who developed pneumonia during the follow-up period were selected as cases, and 66 women who did not develop pneumonia were randomly chosen to serve as control subjects. A questionnaire was administered in subjects' homes that assessed demographics, home environment, and socioeconomic status. Women were followed in the cohort for a median of 36.8 months (range, 27.3-39.3). Adjusting for length of follow-up period, factors associated with lower socioeconomic status (lower monthly spending [OR = 3.2; 95% CI, 1.2-8.4 per 10,000 Kenyan shilling decrease], having no savings [OR = 4.1; 95% CI, 1.4-11.9], less sturdy home construction material such as mud or cement walls [OR = 2.6; 95% CI, 1.1-5.9] or dirt floors [OR = 2.8; 95% CI, 1.0-7.6], and lack of a window in the home [OR = 5.5; 95% CI, 0.9-32.2]) and being widowed (OR = 4.3; 95% CI, 1.2-15.1) or single (OR = 3.3; 95% CI, 1.0-11.2) were associated with an increased risk of pneumonia. In multivariate analysis, widowed (AOR = 5.9; 95% CI, 1.3-26.3), single (AOR = 7.7; 95% CI, 1.6-36.4), and divorced (AOR = 4.5; 95% CI, 1.0-20.1) women, those without savings (AOR = 3.7; 95% CI, 1.2-11.7), and those living in more crowded and contagious conditions (AOR = 1.5; 95% CI, 1.1-2.1) remained at increased risk of pneumonia. If confirmed by prospective investigation, these findings could help identify persons and subpopulations of HIV-infected women with the greatest risk of pneumonia.     

Long-term outcome of Hodgkin disease patients following high-dose busulfan, etoposide, cyclophosphamide, and autologous stem cell transplantation.

Busulfan (Bu)-based preparative regimens have not been extensively investigated in Hodgkin disease (HD). The purposes of this study were to investigate the toxicity and efficacy of a novel preparative regimen of Bu 14 mg/kg, etoposide 50-60 mg/kg, and cyclophosphamide 120 mg/kg in patients with primary refractory and relapsed HD. One hundred twenty-seven patients with a median age of 33 years (range, 14-67 years) underwent transplantation. The regimen was well tolerated, with 5.5% treatment-related mortality at 100 days after transplantation. With a median follow up of 6.7 years, the 5-year progression-free survival was 48 +/- 5%, and the 5-year overall survival was 51 +/- 5%. A Cox proportional hazards model identified refractory disease at time of transplantation as the only significant factor affecting relapse and overall survival, whereas disease bulk >10 cm affected overall survival. Five patients died between 5.3 and 9.3 years of late complications, including secondary myelodysplasia or acute myeloid leukemia, secondary solid malignancies, and pulmonary toxicity. This novel Bu regimen is comparable to other radiation-free preparative regimens in its effectiveness in the control of HD and with a low-risk of early treatment-related mortality.     

Segregation of human immunodeficiency virus type 1 subtypes by risk factor in Australia

The aim of this study was to determine which human immunodeficiency virus type 1 (HIV-1) subtypes were circulating in Australia and to correlate the subtypes with risk factors associated with the acquisition of HIV-1 infection. DNA was extracted from peripheral blood mononuclear cells, and HIV-1 env genes were amplified and subtyped using heteroduplex mobility analysis, with selected samples sequenced and phylogenetic analysis performed. The HIV-1 env subtypes were determined for 141 samples, of which 40 were from female patients and 101 were from male patients; 13 samples were from children. Forty-seven patients were infected by homosexual or bisexual contact, 46 were infected through heterosexual contact, 21 were infected from injecting drug use (IDU), 13 were infected by vertical transmission, 8 were infected from nosocomial exposure, and 6 were infected by other modes of transmission, including exposure to blood products, ritualistic practices, and two cases of intrafamilial transmission. Five subtypes were detected; B (n = 104), A (n = 5), C (n = 17), E (CRF01_AE; n = 13), and G (n = 2). Subtype B predominated in HIV-1 acquired homosexually (94% of cases) and by IDU (100%), whereas non-subtype B infections were mostly seen in heterosexually (57%) or vertically (22%) acquired HIV-1 infections and were usually imported from Africa and Asia. Subtype B strains of group M viruses predominate in Australia in HIV-1 transmitted by homosexual or bisexual contact and IDU. However, non-B subtypes have been introduced, mostly acquired via heterosexual contact.     

Induction of micronucleated cells in the shed skin of salamanders (Ambystoma sp.) treated with colchicine or cyclophosphamide

The micronucleus (MN) assay can be used to detect the genotoxic effects of chemical agents in virtually any cell that divides frequently. Salamanders (Ambystoma sp.) are amphibians that can be easily maintained and bred in the laboratory and spontaneously shed their skin every 2.5-4 days. In this present study, we have evaluated the usefulness of this shed skin for the MN assay. We exposed salamanders to different concentrations of both the aneugen colchicine (COL) and the clastogen cyclophosphamide (CP) and we determined the frequency of micronucleated cells (MNCs) in their sheds. Fragments of shed skin were placed on clean slides, fixed, stained, observed with a light microscope, and the number of MNCs was counted. The MNC frequency was increased significantly by all doses of COL and CP tested, administered either as single or repeated exposures. The presence of MNCs in the shed skin and the speed of sloughing lead us to propose that the sheds of Ambystoma sp., or other amphibians that slough their skin, are suitable alternative models for detecting genotoxic exposures relevant to aquatic environments.     

Galaxy: a platform for interactive large-scale genome analysis

Accessing and analyzing the exponentially expanding genomic sequence and functional data pose a challenge for biomedical researchers. Here we describe an interactive system, Galaxy, that combines the power of existing genome annotation databases with a simple Web portal to enable users to search remote resources, combine data from independent queries, and visualize the results. The heart of Galaxy is a flexible history system that stores the queries from each user; performs operations such as intersections, unions, and subtractions; and links to other computational tools. Galaxy can be accessed at http://g2.bx.psu.edu.     

Rapid genotyping of single nucleotide polymorphisms using novel minor groove binding DNA oligonucleotides (MGB probes)

Novel fluorescent oligonucleotides that contain a 3' minor groove binding group (MGB) hybridize to single-stranded targets with increased sequence-specificity compared to ordinary DNA probes. This reduces non-specific probe hybridization and results in low background fluorescence during the 5' nuclease PCR assay (TaqMan, Applied Biosystems, Foster City, CA). We developed a method for closed-tube genotyping using two allele-specific MGB probes labeled with different fluorophores in one reaction. After PCR, tubes were transported to a fluorescence plate-reader for analysis of fluorescence. Common spreadsheet software was used for automated genotype assignment. As an example, DNA samples from 172 hemochromatosis patients were selected and tested for molecular defects in the HFE gene, i.e., mutations in codon 63 and 282. Tight genotype clusters were observed for both codons and results with MGB probes were identical to conventional genotyping (PCR + restriction-fragment-length-polymorphism). We show that this fast and easy method can be used for large-scale (high-throughput) genetic studies but also for routine molecular diagnostics without post-PCR manipulation of amplicons or the need for real-time quantitative PCR machines. Hum Mutat 19:554-559, 2002.     

The expectations and realities of nutrigenomic testing in australia: A qualitative study

BackgroundConsumer genomic testing for nutrition and wellness, (nutritional genomics), is becoming increasingly popular. Concurrently, health‐care practitioners (HPs) working in private practice (including doctors interested in integrative medicine, private genetic counsellors, pharmacists, dieticians, naturopaths and nutritionists) are involved as test facilitators or interpreters.ObjectiveTo explore Australian consumers’ and HPs’ experiences with nutrigenomic testing.MethodSemi‐structured in‐depth interviews were conducted using predominantly purposive sampling. The two data sets were analysed individually, then combined, using a constant comparative, thematic approach.ResultsOverall, 45 interviews were conducted with consumers (n = 18) and HPs (n = 27). Many of the consumer interviewees experienced chronic ill‐health. Nutrigenomic testing was perceived as empowering and a source of hope for answers. While most made changes to their diet/supplements post‐test, self‐reported health improvements were small. A positive relationship with their HP appeared to minimize disappointment. HPs’ adoption and views of nutrigenomic testing varied. Those enthusiastic about testing saw the possibilities it could offer. However, many felt nutrigenomic testing was not the only ‘tool’ to utilize when offering health care.DiscussionThis research highlights the important role HPs play in consumers’ experiences of nutrigenomics. The varied practice suggests relevant HPs require upskilling in this area to at least support their patients/clients, even if nutrigenomic testing is not part of their practice.Patient or public contributionAdvisory group included patient/public group representatives who informed study design; focus group participants gave feedback on the survey from which consumer interviewees were sourced. This informed the HP data set design. Interviewees from HP data set assisted with snowball sampling.