Evaluation of QSAR and ligand enzyme docking for the identification of ABCB1 substrates

P-glycoprotein (P-gp) is an efflux pump that belongs to ATP-binding cassette (ABC) transporter family embedded in the membrane bilayer. P-gp is a polyspecific protein that has demonstrated its function as a transporter of hydrophobic drugs as well as transporting lipids, steroids and metabolic products. Its role in multidrug resistance (MDR) and pharmacokinetic profile of clinically important drug molecules has been widely recognised. In this study, QSAR and enzyme-ligand docking methods were explored in order to classify substrates and non-substrates of P-glycoprotein. A set of 123 compounds designated as substrates (54) or non-substrates (69) by Matsson et al., 2009 was used for the investigation. For QSAR studies, molecular descriptors were calculated using ACD labs/LogD Suite and MOE (CCG Inc.). P-glycoprotein structures available in the Protein data bank were used for docking studies and determination of binding scores using MOE software. Binding sites were defined using co-crystallised ligand structures. Three classification algorithms which included classification and regression trees, boosted trees and support vector machine were examined. Models were developed using a training set of 98 compounds and were validated using the remaining compounds as the external test set. A model generated using BT was identified as the best of three models, with a prediction accuracy of 88%, Mathews correlation coefficient of 0.77 and Youden’s J index of 0.80 for the test set. Inclusion of various docking scores for different binding sites improved the models only marginally

Moments in transformation: Trainee and newly qualified Lifelong learning teachers’ reconceptualization of assessment in practice

This study investigates the pre-and post-training conceptualisations of assessment amongst trainee and recently qualified teachers in the lifelong learning sector in the UK. Using the lens of transformative learning, the study maps out the process, influential factors and time in the shift in conceptualisation. Though designed as a qualitative iterative study, the study employed a combination of statistical tools and content analysis in data analysis. It found that the dominant pre-training conceptualisation of assessment was in its summative essence as a tool for testing and examination and that reconceptualization occurred mostly during practice. The study calls for a review of the structure and content of teacher education in the area of assessment and proposed that post-training development programmes for newly and recently qualified teachers must acknowledge these findings in their teacher development programmes

Microanatomical effects of ethanolic extract of Cola nitida on the stomach mucosa of adult wistar rats

The study investigated the microanatomical effects of the extracts of Cola nitida on the stomach mucosa of adult male Wistar rats. Twenty adult male wistar rats were randomly divided into four equal groups of A, B, C and D (n=5). Animals in experimental groups B, C and D were given 600mg/kg body weight of crude extract of Cola nitida each by oral intubation for five, seven and nine consecutive days respectively, while group A (control) received equivalent volume of distilled water. Twenty four hrs after the last administration, the animals were sacrificed; tissues were harvested and fixed in 10% formol saline for histological analysis. The study revealed necrotized surface epithelium, degenerated gastric mucosa, and loss of glandular elements in the stomachs of experimental groups’ vis-à-vis the control group. These observations were days-dependent; as those groups which received the extract for higher number of days were seen to be adversely affected. In conclusion, Cola nitida at 600mg/kg body weight can cause gastric lesion in animals. This lesion may be pronounced if the administration continued for days. Cola nitida should, therefore, be taken with caution to avoid gastric complications.Keyword: Cola nitida, necrotized, degenerated, stomach mucosa, microanatomy, glandular element

Prevalence, pattern and risk factors for retinal vascular occlusions in a tertiary hospital in Jos, Nigeria

Introduction: Retinal vascular occlusions are the second most common retinal vascular diseases following diabetic retinopathy. They are associated with several systemic and ocular pathologies and are significant causes of visual loss.Objective: This study aims to determine the prevalence, pattern and risk factors for retinal vascular occlusions in a tertiary hospital in Jos,Nigeria.Methodology: A retrospective review of all cases of retinal vascular occlusions seen in the eye clinic from January 2011 to December 2014 was carried out.The patients were identified from the clinic register and their case folders retrieved.The following data were then extracted from the files; patients' age, sex, presenting visual acuity, presence of any systemic disorders and type of retinal vascular occlusion.Data analysis was done using Epi Info 7.Results: Three thousand eight hundred and twenty one new patients were seen during the study period and there were 52 (1.36%) cases of retinal vascular occlusions.Only the case files of 44(84.6%) patients were available and were analysed. These were made up of 17 (39%) males and 27 (61%) females.These had a total of 46 retinal vascular occlusions made up of 37 (80.4%)retinal vein occlusions,8 (17.4%) central retinal artery occlusions and a case (2.2%) of combined central retinal artery and vein occlusion. Hypertension and diabetes were the most common systemic risk factors while glaucoma was the most common ocular association.Conclusion: Retinal vascular occlusions are uncommon in our centre butlead to severe visual loss and are associated with significant systemic pathologies.Keywords: Retinal vein occlusion,retinal artery occlusio

Determinants of maternal mortality in south-western Nigeria: Midwives’ perceptions

Background Maternal mortality remains one of Nigeria's most significant public health challenges. In order to address this issue sustainably, it is necessary to consider the perceptions of all stakeholders involved, including midwives. Objectives To examine the determinants of maternal mortality in south-western Nigeria from the midwife's perspective. Design A cross-sectional study was employed using mixed methods with a semi-structured questionnaire and an in-depth interview guide. Participants Quantitative data were obtained from 215 midwives using a convenience sampling technique. Qualitative data were obtained from 25 midwives from five government health centres, selected using a stratified sampling technique. Methods Quantitative data were analysed using SPSS Version 20 using descriptive and inferential statistics with 95 % confidence intervals, while qualitative data were analysed using thematic analyses. Findings The mean age and work experience of the participants were 35.2 ± 9.3 years and 8.4 ± 7.0 years, respectively. The midwives perceived that the main determinants of maternal mortality were postpartum haemorrhage (86.5 %), hypertensive disorder in pregnancy (80.9 %), mismanagement at mission homes/traditional birth attendant centres (MH/TBAs) (79.1 %) and sepsis (70.1 %). Some of the priority target areas to improve the well-being of pregnant women as identified by the midwives, were increased awareness of pregnancy danger signs (97 %), destigmatising caesarean section (CS) (96 %), regulation of MH/TBAs (92 %), and increased accessibility of hospitals (84 %). Findings from the qualitative data also affirmed that regulating MH/TBAs, destigmatising CS and subsidising healthcare expenses were prerequisites to curbing maternal mortality. Inferential analysis revealed that determinants such as unsafe abortion (p < 0.001), ectopic pregnancy (p = 0.001), domestic violence (p = 0.023), malaria (p = 0.029), short interbirth interval (p = 0.03), and patients’ negative perceptions of CS delivery (p = 0.036) were more commonly perceived to be associated with maternal mortality by younger midwives (age 17–34 years) compared with older midwives

EVALUATION OF THE AGRONOMIC PERFORMANCE AND NUTRITIVE VALUES OF TEPHROSIA BRACTEOLATA GUILL. & PERR. AND GMELINA ARBOREA ROXB PRUNNINGS AT DIFFERENT STAGES OF GROWTH

This study was carried out to investigate the growth, dry matter yield and chemical composition of Tephrosia bracteolata and Gmelina arborea at Teaching and Research Farm, Federal University of Agriculture, Abeokuta, Nigeria. The objective of this study was to evaluate the effect of different stages of growth of T. bracteolata and G. arborea on their agronomic performance, herbage yield and nutritive value in the humid zone of Nigeria. Data were collected at 8, 12, 16 and 20 weeks after planting (WAP). Results showed that T. bracteolata attained the height of 161 cm at 20 WAP, though not significantly different from the height at 16 WAP. The leaf number (24), branch number (7) and dry matter yield of T. bracteolata were recorded highest at 16 WAP. The height of G. arborea was on constant increase throughout the experimental period. The crude protein (CP) and ether extract (EE) contents of the two browse plants were highest at 8 WAP and thereafter, declined throughout the experimental period. Fibre fractions, the neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) had a least value for both browse species at 8 WAP and highest values at 20 WAP. From the study, considering the dry matter yield and nutritive value, T. bracteolata being an annual species, can be harvested at 16 WAP when the quality and quantity will support livestock productivity and can be conserved to be fed to ruminant animals during dry season when feed availability and quality are extremely low. However, planting of G. arborea should be encouraged being a perennial browse plant that will support livestock productivity during the dry season in the tropics. In conclusion, T. bracteolata and G. arborea grow rapidly and are recommended as forage of high nutritive values that meet ruminant animal protein requirements especially during the dry season

The Influence of Surfactant Concentration and Surfactant Type on the Interfacial Tension of Heavy Crude Oil/Brine/Surfactant System

The interfacial tension that exists amid crude oil and brine can be lowered by chemical surfactant flooding as a result of the mobilization of trapped oil. The influence of surfactants on the interfacial tension (IFT) that exists in a heavy crude oil/ brine system was examined experimentally. The influence of surfactant concentration was observed. The laboratory experiments were performed at ambient and reservoir temperatures. Five different surfactants were made use of; two industrial surfactants (Alpha Olefin Sulfonate and Methyl Ester Sulfonate) and three formulated surfactants from vegetable oils (surfactants from Jatropha, Castor, and Palm kernel oils). The heavy crude oil was acquired from a field X in the Niger Delta, and the brine used was prepared in the laboratory. IFT between brine and heavy crude oil was measured by means of the Du NOUY ring. From the results, it was found that the Castor oil derived surfactant performs best at both ambient and reservoir temperatures

Evaluation of Permeability Impairment Due to Surfactant Flooding

In the course of chemical flooding of crude oil reservoirs with surfactants, retention of surfactant particles in the pores of the reservoir rock can cause a major reduction of the reservoir permeability. This can cause serious problems thus unfavourably influencing the economics of oil recovery. An appropriate assessment of the reduction in permeability is essential for the recovery of hydrocarbons. During tertiary recovery of crude oil, a critical evaluation of formation damage is necessary to evade operating costs, as the reservoir rock is extremely sensitive to chemicals injected. The extent to which permeability is reduced cannot be comprehensive for core field scales; it is consequently paramount to study the reduction in the permeability of a core at laboratory scale before field scale estimation. In this paper, an experimental investigation on the reduction in permeability after surfactant injection cores is presented. Surfactants were used to flood the core samples. The permeability of the cores was calculated at the beginning and end of every flood by measuring the differential pressure during surfactant flooding of the cores. From the results, it is evident that there is a strong influence of surfactants on the process of adsorption on reservoir rocks and consequently leading to reduction in permeability