Stable isotope analysis (SIA) has proven to be a useful tool in reconstructing diets, characterizing trophic relationships, elucidating patterns of resource allocation, and constructing food webs. Consequently, the number of studies using SIA in trophic ecology has increased exponentially over the past decade. Several subdisciplines have developed, including isotope mixing models, incorporation dynamics models, lipid-extraction and correction methods, isotopic routing models, and compound-specific isotopic analysis. As with all tools, there are limitations to SIA. Chief among these are multiple sources of variation in isotopic signatures, unequal taxonomic and ecosystem coverage, over-reliance on literature values for key parameters, lack of canonical models, untested or unrealistic assumptions, low predictive power, and a paucity of experimental studies. We anticipate progress in SIA resulting from standardization of methods and models, calibration of model parameters through experimentation, and continued development of several recent approaches such as isotopic routing models and compound-specific isotopic analysis.
Background
Cryptococcal meningitis (CM) remains a common AIDS-defining illness in Africa and Asia. Sub-clinical cryptococcal antigenemia is frequently unmasked with antiretroviral therapy (ART). We sought to define the cost-effectiveness of serum cryptococcal antigen (CRAG) screening to identify persons with sub-clinical cryptococcosis and the efficacy of preemptive fluconazole.
Methods
609 ART-naïve adults with AIDS initiating ART in Kampala, Uganda had a serum CRAG prospectively measured during 2004–2006. The number needed to test/treat (NNT) with a positive CRAG was assessed for ≥30-month outcomes.
Results
In the overall cohort, 50 persons (8.2%) were serum CRAG positive when starting ART. Of 295 people with CD4+ ≤ 100cells/μL and without prior CM, 26 (8.8%: 95% CI: 5.8–12.6%) were CRAG positive of whom 21 were promptly treated with fluconazole (200–400mg) for 2–4 weeks. Clinical CM developed in 3 fluconazole-treated persons, and 30-month survival was 71% (95% CI: 48%–89%). In the 5 CRAG positive persons with CD4+≤ 100 cell/μL treated with ART but did not fluconazole, all died within 2 months of ART initiation.
The NNT with CRAG screening and fluconazole to prevent one CM case is 11.3 (95%CI: 7.9–17.1) at costs of $190 (95%CI: $132–$287). The NNT to save one life is 15.9 (95%CI: 11.1–24.0) at costs of $266 (95% CI: $185–$402). The cost per disability-adjusted life year (DALY) saved is $21 (95%CI: $15 to $32).
Conclusions
Integrating CRAG screening into HIV care, specifically targeting people with severe immunosuppression (CD4+≤ 100 cells/μL) should be implemented in treatment programs in resource-limited settings. ART alone is insufficient treatment for CRAG-positive persons.
Seborrheic dermatitis (SD) is characterized by erythematous pruritic patches and plaques with greasy scale that occur in sebaceous areas. It is common, affecting up to 3% of the population. Past treatments have relied on a wide variety of anti-inflammatory and antifungal agents, but corticosteroids have limited use because of long-term adverse effects. Topical calcineurin inhibitors provide a safe alternative for the treatment of SD, as these drugs block the inflammatory cascade involved in the disease process and pose no risk of skin atrophy. Studies of topical pimecrolimus and tacrolimus in the treatment of SD have found that improvement occurred within 2 weeks, and if SD recurred after stopping treatment, it was significantly less severe. There have been no studies of the comparative efficacy of pimecrolimus versus tacrolimus for the treatment of SD. Common adverse effects of mild burning and irritation have been associated with the use of both of these agents. Safety profile studies are limited to studies of atopic dermatitis, which show no increase in infection rate, photocarcinogenicity, or signs of immunosuppression in patients using topical calcineurin inhibitors for long-term treatment. This article reviews the clinical trials of pimecrolimus and tacrolimus in the treatment of SD, focusing on efficacy and safety.
We assessed the clinical course of patients after store and forward teledermatology in comparison with conventional consultations. Patients being referred from primary care to dermatology clinics were randomly assigned to teledermatology or a conventional consultation. A total of 392 patients were randomized; 261 patients completed the study and were included in the analysis. Their clinical course was rated on a five-point scale by a panel of three dermatologists, blinded to study assignment, who reviewed serial digital image sets. The clinical course was assessed by comparing images sets between baseline and first clinic visit (if one occurred) and between baseline and nine months. There was no evidence to suggest a difference between the two groups in either clinical course between baseline and nine months post-referral (P = 0.88) or between baseline and the first dermatology clinic visit (P = 0.65). Among teledermatology referrals, subsequent presentation for an in-person dermatology clinic visit was significantly correlated with clinical course (P = 0.023). Store and forward teledermatology did not result in a significant difference in clinical course at either of two post-referral time periods.
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