Conventional and variant termination of the portal vein in a black Kenyan population

Background: Knowledge of the variant terminations of the portal vein is important in surgical and interventional radiological procedures of the liver. Their pattern and frequency are important in planning surgery to minimize complications. They differ between populations, but data from Africa is unavailable. Aim: To investigate the variant termination of the main portal vein. Materials and Methods: One hundred livers from adult black Kenyans (age range 35 – 79 years) were studied at the Department of Human Anatomy, University of Nairobi, Kenya, by gross dissection. The livers were cleared of blood, fixed with 10% formaldehyde solution and the venous system infused with Acrylate monomers to keep the veins firm. The level of termination relative to the capsule and the branching pattern of the portal vein were examined.  Various patterns were photographed using a digital camera. Data was analyzed using SPSS version 16.0 for windows and presented in tables and macrographs. Results: Main portal vein termination was extracapsular in 14%, capsular in 40% and intrahepatic in 46%. Variant termination occurred in 49% of cases while conventional bifurcation occurred in 51% cases. Types, 2, 3 and 4 pattern of termination of main portal vein occurred in 15%, 22% and 12% cases respectively. The level of termination of the MPV had a positive correlation with its pattern (p=0.05). Conclusions: The high prevalence of variant termination of MPV in the current study suggests that the population is more vulnerable to inadvertent injury during surgery and radiological intervention. Besides, an extra hepatic termination of the MPV is more likely to have a conventional branching pattern compared to an intra-hepatic termination

Variant anatomy of the right portal vein in a black Kenyan population

Surface mapping of the liver before invasive procedures depends on a proper understanding of its segmental vasculature. The right portal vein ramification and lengths show marked variations and these mostly involve its right posterior sectoral branch. Their incidence is variable among populations and altogether undocumented among Africans. One hundred livers obtained during autopsies and dissections at the Department of Human anatomy, University of Nairobi, were used in this study. Gross dissection was done to reveal and determine the branching pattern of the right portal vein and the origin of the right posterior sector branch. The lengths of the right portal vein were also measured and recorded. When present, the right portal vein terminated by bifurcation in 61% of the cases, trifurcated in 20.8% and quadrifircated in 18.2%. Its length was between 0.5cm and 4cm. The right posterior sector vein was given off the main portal vein in 34 cases, the common left portal vein trunk in 15 cases, and the right portal vein in 42 cases. In 9 cases, it was not observed at the porta hepatis. We report significant different incidences of the variant anatomy of the right portal vein compared to those found in previous studies and this should be borne in mind when doing surgical interventions.Keywords: Segmentectomy, transjugular, Surface mapping, Bifurcatio

Placental Structure in Preterm Birth Among HIV-Positive Versus HIV-Negative Women in Kenya.

BackgroundPreterm birth (PTB) is a major cause of infant morbidity and mortality in developing countries. Recent data suggest that in addition to Human Immunodeficiency Virus (HIV) infection, use of antiretroviral therapy (ART) increases the risk of PTB. As the mechanisms remain unexplored, we conducted this study to determine whether HIV and ART were associated with placental changes that could contribute to PTB.SettingWe collected and evaluated placentas from 38 HIV-positive women on ART and 43 HIV-negative women who had preterm deliveries in Nairobi, Kenya.MethodsAnatomical features of the placentas were examined at gross and microscopic levels. Cases were matched for gestational age and compared by the investigators who were blinded to maternal HIV serostatus.ResultsAmong preterm placentas, HIV infection was significantly associated with thrombosis (P = 0.001), infarction (P = 0.032), anomalies in cord insertion (P = 0.02), gross evidence of membrane infection (P = 0.043), and reduced placental thickness (P = 0.010). Overall, preterm placentas in both groups were associated with immature villi, syncytial knotting, villitis, and deciduitis. Features of HIV-positive versus HIV-negative placentas included significant fibrinoid deposition with villus degeneration, syncytiotrophoblast delamination, red blood cell adhesion, hypervascularity, and reduction in both surface area and perimeter of the terminal villi.ConclusionsThese results imply that HIV infection and/or ART are associated with morphological changes in preterm placentas that contribute to delivery before 37 weeks. Hypervascularity suggests that the observed pathologies may be attributable, in part, to hypoxia. Further research to explore potential mechanisms will help elucidate the pathways that are involved perhaps pointing to interventions for decreasing the risk of prematurity among HIV-positive women

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

Morphology of human myocardial bridges and association with coronary artery disease

Background: The functional significance of myocardial bridging remains controversial. The bridge morphology and structure of the tunneled vessels may modify its ultimate clinical effects. Objective: To describe the morphological characteristics of myocardial bridges and their influence on coronary histology. Design: A descriptive cross-sectional study. Methods: One hundred and nine formalin-fixed adult hearts were evaluated by dissection for these data: prevalence, site, lengths and depths of myocardial. Bridges. Vessel segments proximal and distal to the bridged portion were also processed for histology and stained to elaborate smooth muscle, collagen and elastic fibers. Stereology was also employed to compare the relative sizes of the tunica intima and the vessel wall to lumen ratios. Results: Myocardial bridges were found in 40.4% of the hearts, most commonly in the left anterior descending artery (LAD). The average length of the bridges was 22.66 +11.94 mm while the depth was 1.83+ 0.98mm, with only 11 % being long (34.87mm- 50mm) and 9% of them being deep (3.46mm - 5.Oomm). The tunica intima was thickest proximal to and thinnest under the myocardial bridge. The intima of the proximal segment was also more elastic. An elaborate perivascular `cushion′ of adipose tissue intervened between the intramural coronary and the surrounding myocardium. Conclusions: Most myocardial bridges are superficial and short. Tunica intima under myocardial bridges is spared from ". The thick perivascular space around the bridged segment may protect it from extreme compression

Placental Structure in Preterm Birth Among HIV-Positive Versus HIV-Negative Women in Kenya.

BackgroundPreterm birth (PTB) is a major cause of infant morbidity and mortality in developing countries. Recent data suggest that in addition to Human Immunodeficiency Virus (HIV) infection, use of antiretroviral therapy (ART) increases the risk of PTB. As the mechanisms remain unexplored, we conducted this study to determine whether HIV and ART were associated with placental changes that could contribute to PTB.SettingWe collected and evaluated placentas from 38 HIV-positive women on ART and 43 HIV-negative women who had preterm deliveries in Nairobi, Kenya.MethodsAnatomical features of the placentas were examined at gross and microscopic levels. Cases were matched for gestational age and compared by the investigators who were blinded to maternal HIV serostatus.ResultsAmong preterm placentas, HIV infection was significantly associated with thrombosis (P = 0.001), infarction (P = 0.032), anomalies in cord insertion (P = 0.02), gross evidence of membrane infection (P = 0.043), and reduced placental thickness (P = 0.010). Overall, preterm placentas in both groups were associated with immature villi, syncytial knotting, villitis, and deciduitis. Features of HIV-positive versus HIV-negative placentas included significant fibrinoid deposition with villus degeneration, syncytiotrophoblast delamination, red blood cell adhesion, hypervascularity, and reduction in both surface area and perimeter of the terminal villi.ConclusionsThese results imply that HIV infection and/or ART are associated with morphological changes in preterm placentas that contribute to delivery before 37 weeks. Hypervascularity suggests that the observed pathologies may be attributable, in part, to hypoxia. Further research to explore potential mechanisms will help elucidate the pathways that are involved perhaps pointing to interventions for decreasing the risk of prematurity among HIV-positive women