Stroke injury, cognitive impairment and vascular dementia

AbstractThe global burden of ischaemic strokes is almost 4-fold greater than haemorrhagic strokes. Current evidence suggests that 25–30% of ischaemic stroke survivors develop immediate or delayed vascular cognitive impairment (VCI) or vascular dementia (VaD). Dementia after stroke injury may encompass all types of cognitive disorders. States of cognitive dysfunction before the index stroke are described under the umbrella of pre-stroke dementia, which may entail vascular changes as well as insidious neurodegenerative processes. Risk factors for cognitive impairment and dementia after stroke are multifactorial including older age, family history, genetic variants, low educational status, vascular comorbidities, prior transient ischaemic attack or recurrent stroke and depressive illness. Neuroimaging determinants of dementia after stroke comprise silent brain infarcts, white matter changes, lacunar infarcts and medial temporal lobe atrophy. Until recently, the neuropathology of dementia after stroke was poorly defined. Most of post-stroke dementia is consistent with VaD involving multiple substrates. Microinfarction, microvascular changes related to blood–brain barrier damage, focal neuronal atrophy and low burden of co-existing neurodegenerative pathology appear key substrates of dementia after stroke injury. The elucidation of mechanisms of dementia after stroke injury will enable establishment of effective strategy for symptomatic relief and prevention. Controlling vascular disease risk factors is essential to reduce the burden of cognitive dysfunction after stroke. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock

Dietary Effect of Substituting \u3cem\u3ePanicum maximum\u3c/em\u3e with \u3cem\u3eTithonia diversifolia\u3c/em\u3e Forage on Performance of Yankasa Sheep

Ruminant livestock production in Nigeria is based predominantly on native grassland (especially Panicum maximum); the nutritive value of the natural pasture varies drastically according to season (Ademosun.1992). Changes in nutritional status of these native plants result in very irregular growth and marked fluctuations in seasonal weights of farm animals. Consequently, it becomes imperative to source for alternative feed resources which are more efficient, economical and can be incorporated into ruminant’s diet with a view to reducing feed costs and hence, achieving a greater profit margin for the producer. Tithonia diversifolia is an herbaceous weed of field crops and is widely distributed in the humid and sub-humid tropical Africa. Tithonia diversifolia could be considered a higher ranking forage species considering its crude protein content that varies between 14.8 and 28.8% (Navarro and Rodriguez 1990), the average of this values compared favourably with the protein content of Gliricidia (14.7%) Leucaena (22.2%) and Peppiginna (21.4%) as reported by Rosales (1996). However, there is dearth of information on its use as ruminant feed in Nigeria. Therefore, this study was designed to evaluate the dietary effect of substituting Panicum maximum with Tithonia diversifolia forage on performance of Yankasa sheep

Aflatoxin contamination of maize vended in Ondo state, Nigeria, and health risk assessment

Aflatoxin contamination of maize is a serious food safety problem worldwide. Despite the widespread consumption of maize in Nigeria, there is limited data on aflatoxin contents of maize vended in open markets in Ondo state, Nigeria. A total of 140 maize samples randomly purchased from major markets in four locations in Ondo state, were screened for total aflatoxins using an ELISA method. Exposure and health risk assessments were performed for the maize consumers by the deterministic and Margin of exposure (MOE) approaches, respectively. About 99% of the maize were contaminated with total aflatoxins (range: 0.65–265 µg/kg; mean: 125.9 µg/kg). Aflatoxin levels exceeding the 4 µg/kg set by the European Union for total aflatoxins were found in 88% of the maize whilst more than one half contained at least 100 µg/kg aflatoxins. The average probable daily intake values were 830, 332 and 138 ng/kg bw/day for the average children, adolescent and adult populations, respectively. Consequently, MOEs for the respective populations were 0.20, 0.51 and 1.23, suggesting a high level of health risk for consumers of maize vended in open markets in Ondo state due to high aflatoxin levels. Maize farmers and households in Ondo state need urgent aflatoxin mitigation interventions

Teaching strategy preferences in upper basic schools in Ilorin west local government area, Kwara state, Nigeria

Introduction: Several studies have been carried out on various teaching strategy broadly categorised as teacher-centred, student-centred and student-teacher centred. This study was premised on investigating preferences for these strategies among basic school teachers. Purpose: This study aimed to investigate teacher's teaching strategy preferences in classroom situations in teaching and learning in Upper Basic Classroom situations. Methodology: The study adopted a descriptive research design of survey type. Teachers in Ilorin West Local Government area of Kwara State constituted the study population while the target population was all Upper Basic school teachers sampled randomly. The instrument used to collect data was a questionnaire tagged "Teachers' Teaching Strategy Preferences Questionnaire" (TTSPQ) which was face and content validated by measurement and evaluation experts. The reliability of the instrument was ascertained using Cronbach's alpha with a reliability index of 0.78. The validated instrument was administered electronically via Google Forms. Data were analysed using percentages, t-test and ANOVA statistics. Results: Results showed that teacher-student centred strategy using discussion, demonstration, question & answer, field trip, and reciprocal methods were preferred while there was a significant difference in teaching strategy preferences based on teaching the subject with Mathematics teachers most contributors to the significance. Recommendations/Classroom Implications: It was recommended that schools constantly organise training and workshops to better expose all teachers to deploying student-teacher-centred teaching and learning methods

Food safety in the face of climate change: consequences for consumers

Food safety encompasses the elimination of biological, chemical, and physical hazards along the food chain; however, climate change, an abnormal change in weather conditions, is a threat to food safety due to irregularities in the elements of weather essential for food production. Such factors include elevated atmospheric carbon (IV) oxide (CO2), precipitation, rainfall, and temperature. Considering that the aim of food safety is to eliminate food hazards along the food chain, it is threatened by climate change in several ways, resulting in adverse effects such as severe consequences for livestock production, harmful algal bloom, mycotoxins (produced by mycotoxigenic fungi on crops), residues of pesticides and tenacious contaminants, and pathogenic microorganisms from contaminated water. These climate changes include landslides and avalanches, drought and extreme heat waves, drought, heavy precipitation, flooding and tropical storms, ocean warming, climate change related acidification, and changes in ocean salinity. Therefore, there is a great need to employ adaptive strategies such as the establishment of a food safety management programme which would expound on the need to detect food hazards in food as a result of climate change. This programme should include setting up awareness for consumers, the improvement of epidemiological surveillance, improved co-ordination among food safety organizations, public health officials, and veterinary officials, amongst others. Thus, to achieve the sustainable development goal two, of eradicating hunger, it is imperative to harness the strategies for reducing the food safety hazards associated with climate change

Intraligamentary Extrauterine Pregnancy Delivered at Term: A Case Report and Review of Literature

Intraligamentary pregnancy is extremely rare. Preoperative diagnosis is often difficult. We report a case of a 33 year old female who had an ectopic pregnancy in the right broad ligament. The pregnancy remained viable till term, but unfortunately resulted in a perinatal death prior delivery. Diagnosis was not made until laparotomy and a well formed still born was delivered. A high index of suspicion and prompt therapeutic intervention are necessary to prevent adverse fetal and or maternal outcome. Keywords: Intraligamentary pregnancy, Full term fetus, Nigeria

PERFORMANCE EVALUATION OF TROPICAL BIOFUELLED FISH SMOKING STRUCTURES

Environmental and hygienic concerns associated with traditional fish smoking structures restrict the sale and consumption of smoked products to local markets. This study evaluated the performance of three(improved kiln oven (IKO), mud-type ovens (MTO) and extended drum ovens (EDO)) locally available Biofuelledfish smoking structures and proposed modifications to improve product quality.Three groups of prepared freshwater catfish (Clarias gariepinus) with average live weights of 1.93 kg±46 g, 1.92 kg±50 g and 1.86 kg±50 g was used as test samples. Smoking profiles, final moisture content (FMC), smoking time, smoking temperatures, percentage weight loss (WL) and organoleptic evaluation (ORE) were the performance indicators used during evaluatio

Loss of capillary pericytes and the blood–brain barrier in white matter in poststroke and vascular dementias and Alzheimer’s disease

White matter (WM) disease is associated with disruption of the gliovascular unit, which involves breach of the blood‐brain barrier (BBB). We quantified pericytes as components of the gliovascular unit and assessed their status in vascular and other common dementias. Immunohistochemical and immunofluorescent methods were developed to assess the distribution and quantification of pericytes connected to the frontal lobe WM capillaries. Pericytes with a nucleus were identified by collagen 4 (COL4) and platelet derived growth factor receptor‐β (PDGFR‐β) antibodies with further verification using PDGFR‐β specific ELISA. We evaluated a total of 124 post‐mortem brains from subjects with post‐stroke dementia (PSD), vascular dementia (VaD), Alzheimer’s disease (AD), AD‐VaD (Mixed), and post‐stroke non‐demented (PSND) stroke survivors as well as normal ageing controls. COL4 and PDGFR‐β reactive pericytes adopted the characteristic “crescent” or nodule‐like shapes around capillary walls. We estimated densities of pericyte somata to be 225 ±38 and 200 ±13 (SEM) per COL4 mm2 area or 2.0 ±0.1 and 1.7 ±0.1 per mm capillary length in young and older ageing controls. Remarkably, WM pericytes were reduced by ~35‐45 percent in the frontal lobe of PSD, VaD, Mixed and AD subjects compared to PSND and controls subjects (P<0.001). We also found pericyte numbers were correlated with PDGFR‐β reactivity in the WM. Our results first demonstrate a reliable method to quantify COL4‐positive pericytes and then indicate that deep WM pericytes are decreased across different dementias including PSD, VaD, Mixed and AD. Our findings suggest that down regulation of pericytes is associated with the disruption of the BBB in the deep WM in several ageing‐related dementias