HIV-associated neurocognitive disorders in sub-Saharan Africa: a pilot study in Cameroon

<p>Abstract</p> <p>Background</p> <p>The disease burden of human immunodeficiency virus (HIV) - acquired immunodeficiency syndrome (AIDS) is highest in sub-Saharan Africa but there are few studies on the associated neurocognitive disorders in this region. The objectives of this study were to determine whether Western neuropsychological (NP) methods are appropriate for use in Cameroon, and to evaluate cognitive function in a sample of HIV-infected adults.</p> <p>Methods</p> <p>We used a battery of 19 NP measures in a cross-sectional study with 44 HIV+ adults and 44 demographically matched HIV- controls, to explore the validity of these NP measures in Cameroon, and evaluate the effect of viral infection on seven cognitive ability domains.</p> <p>Results</p> <p>In this pilot study, the global mean z-score on the NP battery showed worse overall cognition in the HIV+ individuals. Significantly lower performance was seen in the HIV+ sample on tests of executive function, speed of information processing, working memory, and psychomotor speed. HIV+ participants with AIDS performed worse than those with less advanced HIV disease.</p> <p>Conclusions</p> <p>Similar to findings in Western cohorts, our results in Cameroon suggest that HIV infection, particularly in advanced stages, is associated with worse performance on standardized, Western neurocognitive tests. The tests used here appear to be promising for studying NeuroAIDS in sub-Saharan Africa.</p

Epidemiology of neurodegenerative diseases in sub-Saharan Africa: a systematic review

BACKGROUND:Sub-Saharan African (SSA) countries are experiencing rapid transitions with increased life expectancy. As a result the burden of age-related conditions such as neurodegenerative diseases might be increasing. We conducted a systematic review of published studies on common neurodegenerative diseases, and HIV-related neurocognitive impairment in SSA, in order to identify research gaps and inform prevention and control solutions. METHODS: We searched MEDLINE via PubMed, 'Banque de Donnees de Sante Publique' and the database of the 'Institut d'Epidemiologie Neurologique et de Neurologie Tropicale' from inception to February 2013 for published original studies from SSA on neurodegenerative diseases and HIV-related neurocognitive impairment. Screening and data extraction were conducted by two investigators. Bibliographies and citations of eligible studies were investigated. RESULTS: In all 144 publications reporting on dementia (n=49 publications, mainly Alzheimer disease), Parkinsonism (PD, n=20), HIV-related neurocognitive impairment (n=47), Huntington disease (HD, n=19), amyotrophic lateral sclerosis (ALS, n=15), cerebellar degeneration (n=4) and Lewy body dementia (n=1). Of these studies, largely based on prevalent cases from retrospective data on urban populations, half originated from Nigeria and South Africa. The prevalence of dementia (Alzheimer disease) varied between <1% and 10.1% (0.7% and 5.6%) in population-based studies and from <1% to 47.8% in hospital-based studies. Incidence of dementia (Alzheimer disease) ranged from 8.7 to 21.8/1000/year (9.5 to 11.1), and major risk factors were advanced age and female sex. HIV-related neurocognitive impairment's prevalence (all from hospital-based studies) ranged from <1% to 80%. Population-based prevalence of PD and ALS varied from 10 to 235/100,000, and from 5 to 15/100,000 respectively while that for Huntington disease was 3.5/100,000. Equivalent figures for hospital based studies were the following: PD (0.41 to 7.2%), ALS (0.2 to 8.0/1000), and HD (0.2/100,000 to 46.0/100,000). CONCLUSIONS: The body of literature on neurodegenerative disorders in SSA is large with regard to dementia and HIV-related neurocognitive disorders but limited for other neurodegenerative disorders. Shortcomings include few population-based studies, heterogeneous diagnostic criteria and uneven representation of countries on the continent. There are important knowledge gaps that need urgent action, in order to prepare the sub-continent for the anticipated local surge in neurodegenerative diseases

Timing of hospital arrival in stroke patients in Benin City Nigeria

Introduction: The aim of this study was to observe the time of arrival to hospital of stroke patients in Benin City, Edo state and to present the predictors of delayed presentation after acute stroke.Method: This is an observational cross sectional study which was carried out in the medical wards of Central Hospital, Benin City and University of Benin Teaching Hospital, Benin City. We studied one hundred patients with a clinical diagnosis of stroke and also with neuro-imaging (CT scan brain) findings consistent with stroke, for timing of hospital arrival and predictors of delayed presentation.Results: A total of one hundred patients were seen during the study period. Sixty males and forty females. The mean age of patients was 61±12.7 years. The median time of presentation to hospital was 48hours. 38% of patients presented within 3hours, while 62% presented after 3hours. Patients older than 65years of age and patients who were referred from another center were significantly more likely to present late after a stroke.Conclusion: Our study supports the need for educational programs and stroke campaigns to increase awareness of the public and health professionals to improve early arrival of patients to hospital

Is there a change in the prevalence of stroke risk factors over the past decade in Benin City, Nigeria?

Aim:Stroke remains a major cause of morbidity and mortality all over the world. Our previous study on the reappraisal of risk factors for stroke over a decade ago identified various risk factors for stroke. With increasing trend in stroke mortality and morbidity in Nigerian Africans, are these stroke risk factors still relevant? This study was designed to identify a decade after, if there has been a change in the pattern of risk factors for stroke. Materials/ Methods:This was an observational cross-sectional study, which recruited eighty-four patients with clinical and neuro-imaging diagnosis of stroke. Risk factors for stroke were determined including hypertension, dyslipidemia, diabetes mellitus, smoking habit, alcohol consumption, obesity, history of previous stroke and cardiac factors. These were compared to stroke risk factors identified in our previous study. Results:The mean age of the subjects was 61.1(12.7) years. 81% of participants were hypertensive and hypertension was still the commonest risk factor for stroke identified. 76.3% had dyslipidaemia while 10.7% were obese which were significantly different from the earlier study. A history of previous stroke (P=0.04), a history of significant alcohol consumption (P=0.026) and a history of cigarette smoking (P=0.014) were associated with more severe strokes. . Conclusion:There has been no major change in the pattern of stroke risk factors. Hypertension remains the most dominant and modifiable risk factor for stroke

Value of demand flexibility for managing wind energy constraint and curtailment

The dispatch-down of excess wind energy is a growing concern especially for countries integrating high levels of variable-renewable energy. Demand flexibility presents an opportunity to move consumer loads to periods of excess wind energy, which could provide numerous values to the system. While previous research has focused on managing wind energy curtailment (a system-wide issue), much wind energy is rejected due to constraint (a local issue) and hence can only be resolved by local load on-demand. This paper provides a framework to assess the value of demand flexibility for managing wind energy constraint and curtailment. A methodology to determine the optimal number of subscribers to yield sufficient reduction in excess wind energy while ensuring reasonable cost-savings for the subscribers is developed. Analysis shows that this optimal number of subscribers could provide a 67% reduction in constraint and a 74% reduction in curtailment. Consumers can save up-to £220 per year, depending on their priority in the dispatch process. A 10-MW wind farm could earn £19,400 annually from avoided curtailments. System operators could save up-to 78% on constraint payments. The paper also assesses the network impact of flexible loads and provides a methodology for calculating the heat-pump hosting capacity of the grid

Xanthine Analogs Suppress <i>Trypanosoma cruzi</i> Infection In Vitro Using PDEs as Targets

Trypanosoma cruzi (T. cruzi), the causative agent of Chagas disease, has infected 6 million people, putting 70 million people at risk worldwide. Presently, very limited drugs are available, and these have severe side effects. Hence, there is an urgency to delve into other pathways and targets for novel drugs. Trypanosoma cruzi (T. cruzi) expresses a number of different cyclic AMP (cAMP)-specific phosphodiesterases (PDEs). cAMP is one of the key regulators of mammalian cell proliferation and differentiation, and it also plays an important role in T. cruzi growth. Very few studies have demonstrated the important role of cyclic nucleotide-specific PDEs in T. cruzi’s survival. T. cruzi phosphodiesterase C (TcrPDEC) has been proposed as a potential new drug target for treating Chagas disease. In the current study, we screen several analogs of xanthine for potency against trypomastigote and amastigote growth in vitro using three different strains of T. cruzi (Tulahuen, Y and CA-1/CL72). One of the potent analogs, GVK14, has been shown to inhibit all three strains of amastigotes in host cells as well as axenic cultures. In conclusion, xanthine analogs that inhibit T. cruzi PDE may provide novel alternative therapeutic options for Chagas disease

Neurocognitive impairment associated with predominantly early stage HIV infection in Abuja, Nigeria

Detailed neuropsychological testing was performed on 134 HIV seropositive (SP) and 77 HIV seronegative (SN) individuals, 86% with early stage HIV infection in Nigeria, to determine the frequency of HIV-related neurocognitive impairment among the HIV-infected group. Twenty-two tests were administered to assess the following seven ability domains: speed of information processing (SIP); attention/working memory (AWM); executive functioning (EF); learning (LN); memory (MEM); verbal fluency (VF); and motor speed/dexterity (MSD). Demographically corrected individual test scores and scores for each domain or reflecting a global deficit (a global deficit score, or GDS) were compared for the SP and SN groups. SP participants were older, had fewer years of education, were more likely to be married, differed in ethnicity and had higher depression scores than SN individuals. On the testing, SP performed worse than SN on four tests that individually assessed LN, VF and MSD (the timed gait). SP subjects, however, performed better than SN on the finger-tapping test, also a motor task. Within the seven ability domains, SP performed worse than SN with respect to SIP, EF, LN, MEM and VF and also on the global measure. SP were also more frequently impaired on tests of SIP, and there was a borderline increase in the frequency of global impairment. Performance by SP subjects was not associated with CD4 counts. However, there were significant correlations between viral load measurements and individual tests of SIP, EF, LN and VF and with overall EF and a borderline correlation with the GDS. Depression scores for SP were associated with impairment on only a single test of EF. These results demonstrate that the ability of these assessments to identify areas of impairment that may be specifically linked to a history of HIV infection among individuals in Nigeria. Confirmation of these findings awaits analyses using data from a larger number of control subjects