Advances in research on the use of biochar in soil for remediation: a review

Purpose: Soil contamination mainly from human activities remains a major environmental problem in the contemporary world. Significant work has been undertaken to position biochar as a readily-available material useful for the management of contaminants in various environmental media notably soil. Here, we review the increasing research on the use of biochar in soil for the remediation of some organic and inorganic contaminants.  Materials and methods: Bibliometric analysis was carried out within the past 10 years to determine the increasing trend in research related to biochar in soil for contaminant remediation. Five exemplar contaminants were reviewed in both laboratory and field-based studies. These included two inorganic (i.e., As and Pb) and three organic classes (i.e., sulfamethoxazole, atrazine, and PAHs). The contaminants were selected based on bibliometric data and as representatives of their various contaminant classes. For example, As and Pb are potentially toxic elements (anionic and cationic, respectively), while sulfamethoxazole, atrazine, and PAHs represent antibiotics, herbicides, and hydrocarbons, respectively.  Results and discussion: The interaction between biochar and contaminants in soil is largely driven by biochar precursor material and pyrolysis temperature as well as some characteristics of the contaminants such as octanol-water partition coefficient (KOW) and polarity. The structural and chemical characteristics of biochar in turn determine the major sorption mechanisms and define biochar’s suitability for contaminant sorption. Based on the reviewed literature, a soil treatment plan is suggested to guide the application of biochar in various soil types (paddy soils, brownfield, and mine soils) at different pH levels (4–5.5) and contaminant concentrations ( 50 mg kg−1).  Conclusions: Research on biochar has grown over the years with significant focus on its properties, and how these affect biochar’s ability to immobilize organic and inorganic contaminants in soil. Few of these studies have been field-based. More studies with greater focus on field-based soil remediation are therefore required to fully understand the behavior of biochar under natural circumstances. Other recommendations are made aimed at stimulating future research in areas where significant knowledge gaps exist

Pre-Exposure Prophylaxis for HIV Prevention : Safety Concerns

Available evidence supports the efficacy of pre-exposure prophylaxis (PrEP) in decreasing the incidence of human immunodeficiency virus (HIV) infection among high-risk individuals, especially when used in combination with other behavioural preventive methods. Safety concerns about PrEP present challenges in the implementation and use of PrEP. The aim of this review is to discuss safety concerns observed in completed clinical trials on the use of PrEP. We performed a literature search on PrEP in PubMed, global advocacy for HIV prevention (Aids Vaccine Advocacy Coalition) database, clinical trials registry " http://www.clinicaltrials.gov " and scholar.google, using combination search terms 'pre-exposure prophylaxis', 'safety concerns in the use of pre-exposure prophylaxis', 'truvada use as PrEP', 'guidelines for PrEP use', 'HIV pre-exposure prophylaxis' and 'tenofovir' to identify clinical trials and literature on PrEP. We present findings associated with safety issues on the use of PrEP based on a review of 11 clinical trials on PrEP with results on safety and efficacy as at April 2016. We also reviewed findings from routine real-life practice reports. The pharmacological intervention for PrEP was tenofovir disoproxil fumarate/emtricitabine in a combined form as Truvada®or tenofovir as a single entity. Both products are efficacious for PrEP and seem to have a good safety profile. Regular monitoring is recommended to prevent long-term toxic effects. The main adverse effects observed with PrEP are gastrointestinal related; basically mild to moderate nausea, vomiting and diarrhea. Other adverse drug effects worth monitoring are liver enzymes, renal function and bone mineral density. PrEP as an intervention to reduce HIV transmission appears to have a safe benefit-risk profile in clinical trials. It is recommended for widespread use but adherence monitoring and real-world safety surveillance are critical in the post-marketing phase to ensure that the benefits observed in clinical trials are maintained in real-world use

Association Between the Occurrence of Adverse Drug Events and Modification of First-Line Highly Active Antiretroviral Therapy in Ghanaian HIV Patients

INTRODUCTION: Patients initiated on highly active antiretroviral therapy (HAART) generally remain on medication indefinitely. A modification in the HAART regimen may become necessary because of possible acute or chronic toxicities, concomitant clinical conditions, development of virological failure or the advent of adverse drug events. The study documents adverse drug events of HIV-positive Ghanaian patients with HAART modifications. It also investigates the association between documented adverse drug events and HAART modification using an unmatched case-control study design. METHOD: The study was conducted in the Fevers Unit of the Korle Bu Teaching Hospital and involved patients who attended the HIV Care Clinic between January 2004 and December 2009. Data from 298 modified therapy patients (cases) were compared with 298 continuing therapy patients (controls) who had been on treatment for at least 1 month before the end of study. Controls were sampled from the same database of a cohort of HIV-positive patients on HAART, at the time a case occurred, in terms of treatment initiation ±1 month. Data were obtained from patients' clinical folders and the HIV clinic database linked to the pharmacy database. The nature of the documented adverse drug events of the cases was described and the association between the documented adverse drug events and HAART modification was determined by logistic regression with reported odds ratios (ORs) and their 95 % confidence interval (CI). RESULTS: Among the 298 modified therapy patients sampled in this study, 52.7 % of them had at least one documented adverse drug event. The most documented adverse drug event was anaemia, recorded in 18.5 % of modified therapy patients, all of whom were on a zidovudine-based regimen. The presence of documented adverse drug events was significantly associated with HAART modification [adjusted OR = 2.71 (95 % CI 2.11-3.48), p < 0.001]. CONCLUSION: Among HIV patients on HAART, adverse drug events play a major role in treatment modification. Occurrence of adverse drug events may be used as a predictor for possible therapy modification. We recommend the institution of active pharmacovigilance in HIV treatment programmes as it permits the proper identification and characterisation of drug-related adverse events. This can help develop approaches towards their management and also justify therapy modifications

Tenofovir-associated renal toxicity in a cohort of HIV infected patients in Ghana

OBJECTIVE: Tenofovir disoproxil fumarate (TDF) is a nucleotide analogue recommended in international HIV treatment guidelines. Purpose of this study was to estimate the long term effects of TDF on renal profile in a cohort of HIV patients in Ghana. Three hundred (300) consecutive HIV-positive patients who initiated TDF-based antiretroviral treatment in 2008 at the Korle-Bu Teaching Hospital were sampled. Creatinine clearance (CrCl) was calculated using the Cockcroft-Gault equation at baseline and renal impairment was defined as CrCl values of 30.0-49.9 mL/min (moderate renal impairment) and < 30 mL/min (severe renal impairment) as per institutional guidelines for renal function test. RESULTS: Median follow up time was 2.9 years (IQR 2.3-3.4 years). At study endpoint, 63 participants (21.0% [95% CI 6.5-26.1]) recorded CrCl rate below 50 mL/min indicating incident renal impairment, made up of 18.3% moderate renal impairment and 2.3% severe renal impairment. Factors associated with incidence of renal impairment were increasing age, decrease in creatinine clearance rate at baseline, WHO HIV stage III/IV and participants with BMI of < 18.5 kg/m2. Patients with identified renal impairment risk factors at ART initiation should be targeted and monitored effectively to prevent renal injury

Adverse events and adherence to HIV post-exposure prophylaxis : a cohort study at the Korle-Bu Teaching Hospital in Accra, Ghana

BACKGROUND: There is strong evidence that post-exposure prophylaxis (PEP) with antiretroviral drugs in the timely management of occupational exposures sustained by healthcare workers decreases the risk of HIV infection and PEP is now widely used. Antiretroviral drugs have well documented toxicities and produce adverse events in patients living with HIV/AIDS. In the era of "highly active antiretroviral therapy", non-adherence to treatment has been closely linked to the occurrence of adverse events in HIV patients and this ultimately influences treatment success but the influence of adverse events on adherence during PEP is less well studied. METHODS: Following the introduction of a HIV post-exposure prophylaxis program in the Korle-Bu Teaching Hospital in January 2005, the incidence of adverse events and adherence were documented in occupationally-exposed healthcare workers (HCWs) and healthcare students (HCSs). Cohort event monitoring was used in following-up on exposed HCWs/HCSs for the two study outcomes; adverse events and adherence. All adverse events reported were grouped by MedDRA system organ classification and then by preferred term according to prophylaxis regimen. Adherence was determined by the completion of prophylaxis schedule. Cox proportional regression analysis was applied to determine the factors associated with the cohort study outcomes. Differences in frequencies were tested using the Chi square test and p < 0.05 was considered statistically significant. RESULTS: A total of 228 exposed HCWs/HCSs were followed up during the study, made up of 101 exposed HCWs/HCSs administered lamivudine/zidovudine (3TC/AZT) for 3 days; 75 exposed HCWs/HCSs administered lamivudine/zidovudine (3TC/AZT) for 28 days; and 52 exposed HCWs/HCSs administered lamivudine/zidovudine/lopinavir-ritonavir (3TC/AZT/LPV-RTV) for 28 days. The frequency of adverse events was 28% (n = 28) in exposed HCWs/HCSs administered 3TC/AZT for 3 days, 91% (n = 68) in exposed HCWs/HCSs administered 3TC/AZT for 28 days and 96% (n = 50) in exposed HCWs/HCSs administered 3TC/AZT/LPV-RTV for 28 days. Nausea was the most commonly reported adverse events in all three regimens. Adherence was complete in all exposed HCWs/HCSs administered 3TC/AZT for 3days, 56% (n = 42) in exposed HCWs/HCSs administered 3TC/AZT for 28 days and 62% (n = 32) in exposed HCWs/HCSs administered 3TC/AZT/LPV-RTV for 28 days. In the Cox regression multi-variate analysis, exposed HCWs/HCSs administered 3TC/AZT for 3 days were 70% less likely to report adverse events compared with exposed HCWs/HCSs administered 3TC/AZT for 28 days (Adjusted HR = 0.30 [95% CI, 0.18-0.48], p < 0.001). Exposed HCWs/HCSs administered 3TC/AZT for 3 days were 75% more likely to adhere to the schedule compared with exposed HCWs/HCSs administered 3TC/AZT for 28 days (Adjusted HR = 1.75 [95% CI, 1.16-2.66], p = 0.008). CONCLUSION: The intolerance to adverse events was cited as the sole reason for truncating PEP, thereby indicating the need for adequate, appropriate and effective counselling, education, active follow-up (possibly through mobile /phone contact) and management of adverse events. Education on the need to complete PEP schedule (especially for exposed HCWs/HCSs on 28-day schedule) can lead to increased adherence, which is very critical in minimizing the risk of HIV sero-conversion. The present results also indicate that cohort event monitoring could be an effective pharmacovigilance tool in monitoring adverse events in exposed HCWs/HCSs on HIV post-exposure prophylaxis

Adverse events and adherence to HIV post-exposure prophylaxis: a cohort study at the Korle-Bu Teaching Hospital in Accra, Ghana

BACKGROUND: There is strong evidence that post-exposure prophylaxis (PEP) with antiretroviral drugs in the timely management of occupational exposures sustained by healthcare workers decreases the risk of HIV infection and PEP is now widely used. Antiretroviral drugs have well documented toxicities and produce adverse events in patients living with HIV/AIDS. In the era of "highly active antiretroviral therapy", non-adherence to treatment has been closely linked to the occurrence of adverse events in HIV patients and this ultimately influences treatment success but the influence of adverse events on adherence during PEP is less well studied. METHODS: Following the introduction of a HIV post-exposure prophylaxis program in the Korle-Bu Teaching Hospital in January 2005, the incidence of adverse events and adherence were documented in occupationally-exposed healthcare workers (HCWs) and healthcare students (HCSs). Cohort event monitoring was used in following-up on exposed HCWs/HCSs for the two study outcomes; adverse events and adherence. All adverse events reported were grouped by MedDRA system organ classification and then by preferred term according to prophylaxis regimen. Adherence was determined by the completion of prophylaxis schedule. Cox proportional regression analysis was applied to determine the factors associated with the cohort study outcomes. Differences in frequencies were tested using the Chi square test and p < 0.05 was considered statistically significant. RESULTS: A total of 228 exposed HCWs/HCSs were followed up during the study, made up of 101 exposed HCWs/HCSs administered lamivudine/zidovudine (3TC/AZT) for 3 days; 75 exposed HCWs/HCSs administered lamivudine/zidovudine (3TC/AZT) for 28 days; and 52 exposed HCWs/HCSs administered lamivudine/zidovudine/lopinavir-ritonavir (3TC/AZT/LPV-RTV) for 28 days. The frequency of adverse events was 28% (n = 28) in exposed HCWs/HCSs administered 3TC/AZT for 3 days, 91% (n = 68) in exposed HCWs/HCSs administered 3TC/AZT for 28 days and 96% (n = 50) in exposed HCWs/HCSs administered 3TC/AZT/LPV-RTV for 28 days. Nausea was the most commonly reported adverse events in all three regimens. Adherence was complete in all exposed HCWs/HCSs administered 3TC/AZT for 3days, 56% (n = 42) in exposed HCWs/HCSs administered 3TC/AZT for 28 days and 62% (n = 32) in exposed HCWs/HCSs administered 3TC/AZT/LPV-RTV for 28 days. In the Cox regression multi-variate analysis, exposed HCWs/HCSs administered 3TC/AZT for 3 days were 70% less likely to report adverse events compared with exposed HCWs/HCSs administered 3TC/AZT for 28 days (Adjusted HR = 0.30 [95% CI, 0.18-0.48], p < 0.001). Exposed HCWs/HCSs administered 3TC/AZT for 3 days were 75% more likely to adhere to the schedule compared with exposed HCWs/HCSs administered 3TC/AZT for 28 days (Adjusted HR = 1.75 [95% CI, 1.16-2.66], p = 0.008). CONCLUSION: The intolerance to adverse events was cited as the sole reason for truncating PEP, thereby indicating the need for adequate, appropriate and effective counselling, education, active follow-up (possibly through mobile /phone contact) and management of adverse events. Education on the need to complete PEP schedule (especially for exposed HCWs/HCSs on 28-day schedule) can lead to increased adherence, which is very critical in minimizing the risk of HIV sero-conversion. The present results also indicate that cohort event monitoring could be an effective pharmacovigilance tool in monitoring adverse events in exposed HCWs/HCSs on HIV post-exposure prophylaxis

Tenofovir-associated renal toxicity in a cohort of HIV infected patients in Ghana

OBJECTIVE: Tenofovir disoproxil fumarate (TDF) is a nucleotide analogue recommended in international HIV treatment guidelines. Purpose of this study was to estimate the long term effects of TDF on renal profile in a cohort of HIV patients in Ghana. Three hundred (300) consecutive HIV-positive patients who initiated TDF-based antiretroviral treatment in 2008 at the Korle-Bu Teaching Hospital were sampled. Creatinine clearance (CrCl) was calculated using the Cockcroft-Gault equation at baseline and renal impairment was defined as CrCl values of 30.0-49.9 mL/min (moderate renal impairment) and < 30 mL/min (severe renal impairment) as per institutional guidelines for renal function test. RESULTS: Median follow up time was 2.9 years (IQR 2.3-3.4 years). At study endpoint, 63 participants (21.0% [95% CI 6.5-26.1]) recorded CrCl rate below 50 mL/min indicating incident renal impairment, made up of 18.3% moderate renal impairment and 2.3% severe renal impairment. Factors associated with incidence of renal impairment were increasing age, decrease in creatinine clearance rate at baseline, WHO HIV stage III/IV and participants with BMI of < 18.5 kg/m2. Patients with identified renal impairment risk factors at ART initiation should be targeted and monitored effectively to prevent renal injury