Mercury accumulation in fishes from tropical aquatic ecosystems in the Niger Delta, Nigeria

Fishes are important biomarkers of trace elements in aquatic ecosystems, and are used to evaluate the status of water pollution by mercury in tropical aquatic ecosystems in Nigeria. Common fishes, Chrysichthys nigrodigitatus,Brycinus nurse, Hemichromis fasciatus, Lutianus ava, Oreochromis nilotica, Pomadasys jubelini, Stellifer stellifer and Tilapia guineensis were analysed for Hg accumulation using the cold vapour atomic absorption spectrophotometry technique. The results showed that Hg concentration in P. jubelini was relatively the highest, with a mean concentration of 0.063 ± 0.03 mg kg–1. Other concentration values were 0.044 ± 0.031 mg kg–1 for O. nilotica, 0.026 ± 0.013 mg kg–1 for B. nurse, 0.034 ± 0.034 mg kg–1 for H. fasciatus, 0.023 ± 0.020 mg kg–1 for C. nigrodigitatus and 0.33 ± 0.016 mg kg–1 for L. ava. Concentrations of Hg accumulated by the fishes were low and within internationally accepted limit, not likely to cause mercury poisoning. Because of the high Hg accumulating potential of P. jubelini, it is recommended as a biomarker for assessment of Hg toxicity in a tropical aquatic environment

Adjunctive interferon-γ immunotherapy for the treatment of HIV-associated cryptococcal meningitis: a randomized controlled trial.

BACKGROUND: Interferon-gamma (IFNγ) is of key importance in the immune response to Cryptococcus neoformans. Mortality related to cryptococcal meningitis remains high, and novel treatment strategies are needed. We performed a randomized controlled trial to determine whether addition of IFNγ to standard therapy increased the rate of clearance of cryptococcal infection in HIV-associated cryptococcal meningitis. METHODS: Patients were randomized to amphotericin B 1 mg/kg per day and 5FC 100 mg/kg per day for 2 weeks (standard therapy), standard therapy and IFNγ1b 100 μg days 1 and 3 (IFNγ two doses), or standard therapy and IFNγ1b 100 μg days 1, 3, 5, 8, 10 and 12 (IFNγ six doses). Primary outcome was rate of clearance of cryptococcus from the cerebrospinal fluid (CSF) (early fungicidal activity, EFA) calculated from serial quantitative cultures, previously shown to be independently associated with survival. RESULTS: Rate of fungal clearance was significantly faster in IFNγ containing groups than with standard treatment. Mean EFA [log colony forming unit (CFU)/ml per day] was -0.49 with standard treatment, -0.64 with IFNγ two doses, and -0.64 with IFNγ six doses. Difference in EFA was -0.15 [confidence interval (95% CI) -0.02 to -0.27, P=0.02] between standard treatment and IFNγ two doses, and -0.15 (95% CI -0.05 to -0.26, P=0.006) between standard treatment and IFNγ six doses. Mortality was 16% (14/88) at 2 weeks and 31% (27/87) at 10 weeks, with no significant difference between groups. All treatments were well tolerated. CONCLUSION: Addition of short-course IFNγ to standard treatment significantly increased the rate of clearance of cryptococcal infection from the CSF, and was not associated with any increase in adverse events. Two doses of IFNγ are as effective as six doses

A comparison of the use of X-ray and neutron tomographic core scanning techniques for drilling projects: insights from scanning core recovered during the Alpine Fault Deep Fault Drilling Project

Abstract. It is now commonplace for non-destructive X-ray computed tomography (CT) scans to be taken of core recovered during a drilling project. However, other forms of tomographic scanning are available, and these may be particularly useful for core that does not possess significant contrasts in density and/or atomic number to which X-rays are sensitive. Here, we compare CT and neutron tomography (NT) scans of 85 mm diameter core recovered during the first phase of the Deep Fault Drilling Project (DFDP-1) through New Zealand's Alpine Fault. For the instruments used in this study, the highest resolution images were collected in the NT scans. This allows clearer imaging of some rock features than in the CT scans. However, we observe that the highly neutron beam attenuating properties of DFDP-1 core diminish the quality of images towards the interior of the core. A comparison is also made of the suitability of these two scanning techniques for a drilling project. We conclude that CT scanning is far more favourable in most circumstances. Nevertheless, it could still be beneficial to take NT scans over limited intervals of suitable core, where varying contrast is desired. </jats:p

Petroleum hydrocarbons and limiting nutrients in Macura reptantia, Procambarus clarkii and benthic sediment from Qua Iboe Estuary, Nigeria

The levels of total petroleum hydrocarbons in two commonly consumed benthopelagic shellfishes, Macura reptantia and Procambarus clarkii, harvested from benthic sediment of Qua Iboe Estuary were determined using a gas chromatography with flame-ionization detector. Seventy-two (72) samples each of benthic sediment and the shellfishes were collected monthly between June 2003 and February 2004 covering the peak periods of the wet and dry seasons. Concentrations of hydrocarbons were highly variable and ranged between 5.00 and 232.00 μg/g dry weight of benthic sediment, 3.05 and 11.30 μg/g dry weight of M. reptantia, 1.62 and 9.00 μg/g dry weight of P. clarkii. Pearson’s correlation analysis of total hydrocarbon concentrations in subtidal sediments with levels in the fauna species yielded positive significant (P < 0.05) correlations in M. reptantia (r = 0.737) and P. clarkii (r = 0.924). This is indicative of a long term and chronic accumulation of hydrocarbons in the estuarine ecosystem, reflecting the potential for exposure of the resident biota and the risk to human health

Symptomatic relapse of HIV-associated cryptococcal meningitis in South Africa: the role of inadequate secondary prophylaxis.

OBJECTIVES: Cryptococcal meningitis is the commonest cause of adult meningitis in Southern Africa. A sizeable proportion of this disease burden is thought to be due to symptomatic relapse of previously treated infection. We carried out a study to examine the contribution of inadequate secondary fluconazole prophylaxis to symptomatic relapses of cryptococcal meningitis. DESIGN: A prospective observational study of patients presenting with laboratory-confirmed symptomatic relapse of HIV-associated cryptococcal meningitis between January 2007 and December 2008 at GF Jooste Hospital, a public sector adult referral hospital in Cape Town. OUTCOME MEASURES: Relapse episodes were categorized into 1) patients not taking fluconazole prophylaxis, 2) immune reconstitution inflammatory syndrome (IRIS) and 3) relapses occurring prior to ART in patients taking fluconazole. In-hospital mortality was recorded. RESULTS: There were 69 relapse episodes, accounting for 23% of all cases of cryptococcal meningitis. 43%(n=30) of relapse episodes were in patients not taking fluconazole prophylaxis, 45%(31) were due to IRIS and 12%(8) were in patients pre-ART taking fluconazole. Patients developing relapse due to inadequate secondary prophylaxis had severe disease and high in-hospital mortality (33%). Of the 30 patients not taking fluconazole, 47% (14) had not been prescribed secondary prophylaxis by their healthcare providers. Importantly, we documented no relapses due to fluconazole resistance in this cohort of patients who has received amphotericin B as initial therapy. CONCLUSIONS: Large numbers of relapses of cryptococcal meningitis are due to failed prescription, dispensing, referral for or adherence to secondary fluconazole prophylaxis. Interventions to improve the use of secondary fluconazole prophylaxis are essential

Petroleum Hydrocarbons Accumulation Potential of Shellfishes from Littoral Waters of the Bight of Bonny, Niger Delta, Nigeria.

Total hydrocarbons concentration in four commercially available shellfishes (Ocypoda africanus, Macura reptantia, Procambarus clarkii and Penaeus notialis) from coastal waters of the Niger Delta region of Nigeria were investigated between June 2003 and February 2004 using standard methods. Levels of total hydrocarbons varied significantly depending on biota species, feeding habit and season. The seasonal mean concentrations reported were: 3.98±0.69, 7.95±1.18, 2.24±0.39 and 5.85±0.57 μg g -1 dry weight for M. reptantia, O. africanus, P. clarkii and P. notialis respectively during the wet season. Enhanced concentrations recorded during the dry season were 7.81±2.32, 11.59±2.63, 6.16±2.12 and 9.69±1.90 μg g-1 dry weight for M. reptantia, O. africanus, P. clarkii and P. notialis, respectively. The results obtained indicated seasonal variations which might have been associated with an incidental crude oil spill recorded during the investigation. In general, O. africanus showed higher levels of total hydrocarbons than other species investigated. However, biota species demonstrated hydrocarbon bioaccumulation potential. Regression between the monthly concentrations of total hydrocarbons in each of the biospecimens with the levels in the surface water and sediments indicated statistically significant (p&lt;0.05) relationships. Moreover, comparison of the seasonal mean concentrations using paired sample t-test at 95% confidence level indicated that the concentrations between the dry and wet seasons were statistically significant

Symptomatic relapse of HIV-associated cryptococcal meningitis in South Africa: The role of inadequate secondary prophylaxis

Objectives. Cryptococcal meningitis is the most common cause of adult meningitis in southern Africa. Much of this disease burden is thought to be due to symptomatic relapse of previously treated infection. We studied the contribution of inadequate secondary fluconazole prophylaxis to symptomatic relapses of cryptococcal meningitis. Design. A prospective observational study of patients presenting with laboratory-confirmed symptomatic relapse of HIV-associated cryptococcal meningitis between January 2007 and December 2008 at GF Jooste Hospital, a public sector adult referral hospital in Cape Town. Outcome measures. Relapse episodes were categorised into: (i) patients not taking fluconazole prophylaxis; (ii) immune reconstitution inflammatory syndrome (IRIS); and (iii) relapses occurring prior to ART in patients taking fluconazole. In-hospital mortality was recorded. Results. There were 69 relapse episodes, accounting for 23% of all cases of cryptococcal meningitis; 43% (N=30) of relapse episodes were in patients not receiving fluconazole prophylaxis, 45% (N=31) were due to IRIS, and 12% (N=8) were in patients pre-ART taking fluconazole. Patients developing relapse due to inadequate secondary prophylaxis had severe disease and high in-hospital mortality (33%). Of the 30 patients not taking fluconazole, 47% (N=14) had not been prescribed secondary prophylaxis by their health care providers. We documented no relapses due to fluconazole resistance in these patients who received amphotericin B as initial therapy. Conclusions. A large number of relapses of cryptococcal meningitis are due to failed prescription, dispensing and referral for or adherence to secondary fluconazole prophylaxis. Interventions to improve the use of secondary fluconazole prophylaxis are essential

6'-Methoxy Raloxifene-analog enhances mouse bone properties with reduced estrogen receptor binding

Raloxifene (RAL) is an FDA-approved drug used to treat osteoporosis in postmenopausal women. RAL suppresses bone loss primarily through its role as a selective estrogen receptor modulator (SERM). This hormonal estrogen therapy promotes unintended side effects, such as hot flashes and increased thrombosis risk, and prevents the drug from being used in some patient populations at-risk for fracture, including children with bone disorders. It has recently been demonstrated that RAL can have significant positive effects on overall bone mechanical properties by binding to collagen and increasing bone tissue hydration in a cell-independent manner. A Raloxifene-Analog (RAL-A) was synthesized by replacing the 6-hydroxyl substituent with 6-methoxy in effort to reduce the compound's binding affinity for estrogen receptors (ER) while maintaining its collagen-binding ability. It was hypothesized that RAL-A would improve the mechanical integrity of bone in a manner similar to RAL, but with reduced estrogen receptor binding. Molecular assessment showed that while RAL-A did reduce ER binding, downstream ER signaling was not completely abolished. In-vitro, RAL-A performed similarly to RAL and had an identical concentration threshold on osteocyte cell proliferation, differentiation, and function. To assess treatment effect in-vivo, wildtype (WT) and heterozygous (OIM+/-) female mice from the Osteogenesis Imperfecta (OI) murine model were treated with either RAL or RAL-A from 8 weeks to 16 weeks of age. There was an untreated control group for each genotype as well. Bone microarchitecture was assessed using microCT, and mechanical behavior was assessed using 3-point bending. Results indicate that both compounds produced analogous gains in tibial trabecular and cortical microarchitecture. While WT mechanical properties were not drastically altered with either treatment, OIM+/- mechanical properties were significantly enhanced, most notably, in post-yield properties including bone toughness. This proof-of-concept study shows promising results and warrants the exploration of additional analog iterations to further reduce ER binding and improve fracture resistance

Getting too personal(ized): The importance of feature choice in online adaptive algorithms

Digital educational technologies offer the potential to customize students' experiences and learn what works for which students, enhancing the technology as more students interact with it. We consider whether and when attempting to discover how to personalize has a cost, such as if the adaptation to personal information can delay the adoption of policies that benefit all students. We explore these issues in the context of using multi-armed bandit (MAB) algorithms to learn a policy for what version of an educational technology to present to each student, varying the relation between student characteristics and outcomes and also whether the algorithm is aware of these characteristics. Through simulations, we demonstrate that the inclusion of student characteristics for personalization can be beneficial when those characteristics are needed to learn the optimal action. In other scenarios, this inclusion decreases performance of the bandit algorithm. Moreover, including unneeded student characteristics can systematically disadvantage students with less common values for these characteristics. Our simulations do however suggest that real-time personalization will be helpful in particular real-world scenarios, and we illustrate this through case studies using existing experimental results in ASSISTments. Overall, our simulations show that adaptive personalization in educational technologies can be a double-edged sword: real-time adaptation improves student experiences in some contexts, but the slower adaptation and potentially discriminatory results mean that a more personalized model is not always beneficial.Comment: 11 pages, 6 figures. Correction to the original article published at https://files.eric.ed.gov/fulltext/ED607907.pdf : The Thompson sampling algorithm in the original article overweights older data resulting in an overexploitative multi-armed bandit. This arxiv version uses a normal Thompson sampling algorith

Promoting medical students’ reflection on competencies to advance a global health equities curriculum

Abstract Background The move to frame medical education in terms of competencies – the extent to which trainees “can do” a professional responsibility - is congruent with calls for accountability in medical education. However, the focus on competencies might be a poor fit with curricula intended to prepare students for responsibilities not emphasized in traditional medical education. This study examines an innovative approach to the use of potential competency expectations related to advancing global health equity to promote students’ reflections and to inform curriculum development. Methods In 2012, 32 medical students were admitted into a newly developed Global Health and Disparities (GHD) Path of Excellence. The GHD program takes the form of mentored co-curricular activities built around defined competencies related to professional development and leadership skills intended to ameliorate health disparities in medically underserved settings, both domestically and globally. Students reviewed the GHD competencies from two perspectives: a) their ability to perform the identified competencies that they perceived themselves as holding as they began the GHD program and b) the extent to which they perceived that their future career would require these responsibilities. For both sets of assessments the response scale ranged from “Strongly Disagree” to “Strongly Agree.” Wilcoxon’s paired T-tests compared individual students’ ordinal rating of their current level of ability to their perceived need for competence that they anticipated their careers would require. Statistical significance was set at p < .01. Results Students’ ratings ranged from “strongly disagree” to “strongly agree” that they could perform the defined GHD-related competencies. However, on most competencies, at least 50 % of students indicated that the stated competencies were beyond their present ability level. For each competency, the results of Wilcoxon paired T-tests indicate – at statistically significant levels - that students perceive more need in their careers for GHD-program defined competencies than they currently possess. Conclusion This study suggests congruence between student and program perceptions of the scope of practice required for GHD. Students report the need for enhanced skill levels in the careers they anticipate. This approach to formulating and reflecting on competencies will guide the program’s design of learning experiences aligned with students’ career goals.http://deepblue.lib.umich.edu/bitstream/2027.42/109541/1/12909_2013_Article_919.pd