Equilibrium and kinetic studies of the stannate(IV)-polyol reaction

The stability constants of 1:1 stannate(IV)-polyol complexes in aqueous media have been determined using a conductimetric technique. The constants are fairly large, and lie in the range 5.3-123.0 for the ten ligands investigated. These values were subsequently used in conjunction with kinetic data to postulate a mechanism involving the species Sn(OH)5- as intermediate in the formation of the chelates. The stannate(IV)-polyol reaction, though taking place at higher pH values, is acid-catalysed and follows first-order kinetics in the oxyanion, but at large ligand-oxyanion mole ratios the reaction exhibits zero-order rate dependence on the polyol. These features taken together are consistent with a unimolecular nucleophilic substitution on the oxyanion. KEY WORDS: Hexahydroxystannate(IV), Polyol, Stability constants, Conductimetric method, Mechanism  Bull. Chem. Soc. Ethiop. 2010, 24(3), 447-456

Drop amalgam voltammetric study of lead complexation by natural inorganic ligands in a salt lake

A study of inorganic complexation of lead using drop amalgam voltammetry is described. The study has been carried out in simulated salt lake water and at ionic strength of 7.35 M, the predetermined ionic strength of Lake Katwe. The complexation of lead with the simple ligands (Cl-, CO32-) created anodic waves and the shifts of the peak potentials of lead with the introduction of varying concentrations of each ligand measured. The analysis of these shifts furnished information about the stability constants of the lead complexes which was employed in the calculation of lead species distribution. These mathematical treatments revealed the existence of two lead chloride complexes with corresponding stability constants log b1 = 0.88, log b2 = 2.95; and two carbonate complexes with log b1 = 8.50 and log b2 = 9.62. The results obtained indicate that in Lake Katwe water (25 oC, carbonate alkalinity = 0.11 M, pH 11) approximately 0.00% of total inorganic lead exists as the free ion, and at chloride concentration of 1.8 M only 1.3% of lead exists as the free ion. KEY WORDS: Drop amalgam, Lead speciation, Stability constants, Lake Katwe, Voltammetric complexation, Species distributionBull. Chem. Soc. Ethiop. 2004, 18(1), 91-100. 

The Efficacy of compost, limestone and growth of Leucaena leucocephala (Lam.) de wit, Senna siamea (Lam.) and Eucalyptus grandis W. Hill ex Maid. for the restoration of bacterial functional diversity in the rhizosphere in copper tailings and pyrite soils

The potential of compost, limestone and growth of Leucaena leucocephala (Lam.) de wit, Senna siamea (Lam.) H.S Irwin & Barneby, and Eucalyptus grandis W. Hill ex Maid for the restoration of rhizospheric bacterial functional diversity of pyrite soil and copper tailings was assessed in the field. Pyrite soil and copper tailings were amended with limestone, compost followed by planting of experimental trees after homogenisation. The experimental setup was of split block design with site as a blocking factor; amendment application and growth of trees as the treatment factors. After 12 months of growth, background and rhizospheric pyrite and copper tailings were sampled and their physico-chemical characteristics analysed. The Community Level Physiological Profiles (CLPP) of the same samples were determined using Biolog EcoPlate™. The functional diversity was assessed from the Biolog data using various indices including Average Well Colour Development (AWCD), substrate richness (S) and Shannon-Wiener index (H). Background and rhizospheric untreated pyrite and copper tailings were extremely acidic, with low organic matter content, available phosphorous, total nitrogen, and relatively higher concentrations of available heavy metals and low bacterial functional diversity. Application of amendments and growth of the tree species effectively increased the pH, organic matter content, available phosphorous, total nitrogen, growth of understory plant species, bacterial functional diversity and lowered the available concentrations of heavy metals. AWCD, bacterial species diversity and richness were higher in rhizospheres of leguminous tree species than the non leguminous Eucalyptus grandis, suggesting the suitability of the former for remediation of pyrite and copper tailings. Keywords: efficacy, compost, restoration, bacterial functional diversity, rhizosphere, Biolog Ecoplate

Identification and Analysis of Adulterants in Aphrodisiac Herbal Medicines Sold by Private Herbal Clinics, Pharmacies and Herbal Drug Shops in Kampala, Uganda

High performance thin layer chromatography (HPTLC), high performance liquid chromatography (HPLC), column chromatography and Fourier transform infrared spectrophotometer (FTIR) were used for the identification and analysis of three phosphodiesterase type-5 (PDE-5) inhibitors in 50 randomly selected aphrodisiac herbal samples. Twenty-seven samples were found to contain one or two or all three synthetic PDE-5 inhibitors representing 54% of the analyzed samples. The FTIR spectral characteristics obtained from the isolated compounds were found to be in conformity with those of sildenafil, tadalafil and vardenafil reference standards. Patients who use these herbal sexual enhancers with the notion that they are safe and natural are likely to be exposed to serious health risks related to safety and quality of the herbal products. There is need for additional effort to effectively regulate herbal medicines in order to protect the consumers from the threat of adulteration

Does chronic alcohol use by HIV-infected patients on d4T/3TC/NVP drug regimen effect the HIV viral load and what is the therapeutic window of the drugs, CD4+ count and WBC count in patients with high viral load during the 9 months period of follow up?

The study investigated the effects of chronic alcohol use on HIV viral load in HIV-infected patients on d4T/3TC/NVP drug regimen during 9 months follow up period. It also determined plasma drug concentrations of d4T, 3TC and NVP; CD4+ and WBC counts for patients with high HIV viral load. A case-control study using repeated measures with serial measurements was used. A total of 41 patients (20 alcohol group and 21 control group) were screened for alcohol use using WHO AUDIT tool and chronic alcohol use biomarkers. Blood sampling was done at 3 month intervals for a period of 9 months. HIV viral load was determined using Roche Amplicor HIV-1 monitor test, version 1.5 (Amplicor). The d4T, 3TC and NVP concentrations were determined by Shimadzu Class-VPTM HPLC Chromatography data system version 6.1. The CD4+ cell count was determined using FACSCalibur flow cytometer. The WBC was determined using automated hematological Coulter CBC-5 Hematology Analyzer system. Results show that % patients with HIV viral load ≥400 copies/ml in control group was highest (23.8%, n=5) at 3 month while in chronic alcohol use group, it was at 0 month (35%, n=7) for both WHO AUDIT tool and chronic alcohol-use biomarkers groups. Generally patients with high viral load ≥400 copies/ml was observed in chronic alcohol use as compared to control group in both WHO AUDIT tool and biomarkers group despite of patients having high steady state d4T, 3TC and NVP plasma drug concentrations in circulation that is available to suppress HIV virus. The high viral load could be associated with the emergence of resistance of the HIV virus and these patients generally had a low CD4+ cell count. Some of these patients had no detectable d4T plasma drug concentrations in circulation and most of them with high viral load had sub-therapeutic NVP plasma drug concentrations in their blood circulation. Chronic ethanol use by HIV-infected patients on d4T/3TC/NVP drug regimen increased HIV viral load and the patients with high viral load had sub-therapeutic NVP plasma drug concentrations and some with undetectable d4T drug concentrations in their blood circulation

Chronic alcohol use affects therapeutic steady state plasma drug concentrations of stavudine, lamivudine and nevirapine in HIV-infected patients during 9 months follow up period: WHO AUDIT tool application G

Chronic alcohol consumption is a common problem among the HIV-infected patients on HAART. The study determined the effect of chronic alcohol use on steady state plasma drug concentrations of stavudine (d4T), lamivudine (3TC) and nevirapine (NVP) in HIV-infected patients during the 9 months follow up period. It also determined whether there were some patients with undetectable plasma drug concentrations in their plasma during the follow up. A case control using repeated measures design with serial measurements model, where plasma drug concentrations were measured at 3 month intervals was used. Chronic alcohol-use using WHO AUDIT tool was used to screen patients. A total of 41 patients (21 alcohol group and 20 control group) were followed up for 9 months with blood sampling done at 3 month intervals. The Shimadzu Class-VPTM HPLC Chromatography data system version 6.1 equipment with UV detector was used to measure the plasma drug concentrations. Data was analyzed using SAS 2003 version 9.1 statistical package with repeated measures fixed the model and means were compared using the student t-test. The mean steady state plasma concentration of both d4T and 3TC in chronic alcohol use group were lower than in the control group all throughout the 9 months period of follow-up. The mean steady state plasma drug concentrations of NVP were higher in the alcohol group at 0 and 3 months and lower in the 6 and 9 months as compared to the control group. The mean total plasma NVP concentration was higher in the chronic alcohol group as compared to the control group and the difference was statistically significant (p≤0.05). However some patients had undetectable plasma drug concentrations despite of having ≥ 95 % adherence rate. Chronic alcohol use by the HIV-infected patients lowers the steady state plasma drug concentrations of d4T, 3TC and NVP in patients

Efficacy of Commercially Used Antibacterial Agents against Oral Bacteria Associated with HIV/AIDS Patients in South Western Uganda

Aims: This was to determine efficacy and resistance profiles against commonly used commercial antibacterial agents in Uganda in the management of oral pathogens in HIV/AIDS patients. Study Design: This was an experimental study. Place and Duration of Study: Microbiology Laboratory, Mbarara University of Science and Technology, Mbarara, Uganda between September 2015 and February 2016. Methodology: Bacterial isolates were tested against commercial antibacterial agents in Uganda. Drug shops, pharmacies and hospitals were purposively and conveniently sampled. Drugs commonly used for the management of opportunistic infections amongst HIV/AIDS patients were purchased and used in the laboratory for susceptibility, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using standard protocols. Results: All the bacterial isolates showed mean total resistance above 60% against erythromycin [85 isolates (69.7%)] and cotrimoxazole [79 isolates, (64.8%)]; with injectable gentamicin [97 isolates (79.5%)] and ceftriaxone [105 isolates (86.0%)] displaying high susceptibility; and ciprofloxacin [65 isolates (53.3%)] showing moderate susceptibility. This shows that national policy on effective regulation of these antibacterial agents needs to be revised to ensure that the situation is reversed. Gentamicin showed increased significant mean activity (P***< .005, ANOVA, multiple comparisons) in MIC and MBC when compared with the other antimicrobial agents. Conclusion: Gentamicin was highly efficacious in this study and resistance of these oral bacteria to common commercial antibacterial agents is a major public health burden especially among Uganda HIV/AIDS patients. Improving drug regulation activities will reduce antibacterial resistance and treatment failures. We recommend a survey on the reasons for efficacy of gentamicin against all the commercially available antimicrobials used in this study. We added a space between “above” and “60%”

Field-adapted sampling of whole blood to determine the levels of amodiaquine and its metabolite in children with uncomplicated malaria treated with amodiaquine plus artesunate combination

<p>Abstract</p> <p>Background</p> <p>Artemisinin combination therapy (ACT) has been widely adopted as first-line treatment for uncomplicated falciparum malaria. In Uganda, amodiaquine plus artesunate (AQ+AS), is the alternative first-line regimen to Coartem^®(artemether + lumefantrine) for the treatment of uncomplicated falciparum malaria. Currently, there are few field-adapted analytical techniques for monitoring amodiaquine utilization in patients. This study evaluates the field applicability of a new method to determine amodiaquine and its metabolite concentrations in whole blood dried on filter paper.</p> <p>Methods</p> <p>Twelve patients aged between 1.5 to 8 years with uncomplicated malaria received three standard oral doses of AQ+AS. Filter paper blood samples were collected before drug intake and at six different time points over 28 days period. A new field-adapted sampling procedure and liquid chromatographic method was used for quantitative determination of amodiaquine and its metabolite in whole blood.</p> <p>Results</p> <p>The sampling procedure was successively applied in the field. Amodiaquine could be quantified for at least three days and the metabolite up to 28 days. All parasites in all the 12 patients cleared within the first three days of treatment and no adverse drug effects were observed.</p> <p>Conclusion</p> <p>The methodology is suitable for field studies. The possibility to determine the concentration of the active metabolite of amodiaquine up to 28 days suggested that the method is sensitive enough to monitor amodiaquine utilization in patients. Amodiaquine plus artesunate seems effective for treatment of falciparum malaria.</p

<b>Drop amalgam voltammetric study of lead complexation by natural inorganic ligands in a salt lake</b>

A study of inorganic complexation of lead using drop amalgam voltammetry is described. The study has been carried out in simulated salt lake water and at ionic strength of 7.35 M, the predetermined ionic strength of Lake Katwe. The complexation of lead with the simple ligands (Cl-, CO32-) created anodic waves and the shifts of the peak potentials of lead with the introduction of varying concentrations of each ligand measured. The analysis of these shifts furnished information about the stability constants of the lead complexes which was employed in the calculation of lead species distribution. These mathematical treatments revealed the existence of two lead chloride complexes with corresponding stability constants log &beta;1 = 0.88, log &beta;2 = 2.95; and two carbonate complexes with log &beta;1 = 8.50 and log &beta;2 = 9.62. The results obtained indicate that in Lake Katwe water (25 oC, carbonate alkalinity = 0.11 M, pH 11) approximately 0.00% of total inorganic lead exists as the free ion, and at chloride concentration of 1.8 M only 1.3% of lead exists as the free ion

Validity of self-reported use of sulphadoxine-pyrimethamine intermittent presumptive treatment during pregnancy (IPTp): a cross-sectional study

Abstract Background Malaria in pregnancy is a major health problem that can cause maternal anaemia, stillbirth, spontaneous abortion, low birth weight and intra-uterine stunting. The WHO recommends use of sulphadoxine-pyrimethamine (SP) for intermittent preventive treatment of malaria during pregnancy (IPTp) in endemic areas. Towards monitoring and assessing IPTp coverage in the population, the Roll Back Malaria Partnership recommends the use of self-reported data. The aim of this study was to assess the validity of self-reported IPTp by testing for sulphadoxine in maternal blood at delivery. Methods Two hundred and four pregnant women were consented and enrolled in a cross-sectional study in Mulago National Referral Hospital in Kampala Uganda. - Participants who reported a history of taking sulpha-containing drugs like co-trimoxazole , those who were not sure of dates relating to last menstrual period or who took IPTp within the first 20 weeks of gestation were excluded from the study. Data on demographic characteristics, obstetric history, and delivery outcome were collected. At birth, maternal venous blood was taken off aseptically and used to make thick blood smears for malaria parasites and plasma for determining sulphadoxine using high performance liquid chromatography (HPLC). Results Of 120 participants who self reported to have used IPTp, 35 (29.2%) tested positive for sulphadoxine by HPLC, while 63 (75%) of 84 patients who reported not having used IPTp tested negative for sulphadoxine. Participants possessing post-primary education were more likely to have reported using IPTp. The low agreement (kappa coefficient = 0.037) between self-report and actual presence of the drug in the blood casts doubt on the validity of self-reported data in estimating IPTp coverage. Conclusions The results of this study question the accuracy of self-reported data in estimating IPTp coverage in the population. More studies on validity of self reported data are recommended. Since the validity of IPTp self reports is vital for guiding policy on malaria control in pregnancy, ways should be sought to improve accuracy of the information from such reports.</p