Variant termination of the common carotid artery: Cases of quadrifurcation and pentafurcation

Knowledge of variant termination of common carotid artery is important to prevent inadvertent vascular injury during surgical, interventional and diagnostic radiological neck procedures. The variations show population differences but there are scanty data from the black African populations. Further, though trifurcations have been reported, quadrifurcations and pentafurcations are hitherto undocumented. This study therefore examined the pattern of termination of 208 left common carotid arteries in the black Kenyan population by cadaveric dissection at the Department of Human Anatomy, University of Nairobi. The conventional bifurcation into internal and external carotid arteries occurred in only 128 (61.5%) of cases. Trifurcation occurred in 66 (31.7%), quadrifurcation in 11(5.4%) and pentafurcation in 3 (1.4%). In all cases of trifurcation, superior thyroid artery was the third branch. The common carotid artery quadrifurcated into external, internal carotid, superior thyroid and ascending pharyngeal arteries. The pentafurcations comprised internal carotid, external carotid, superior thyroid, occipital and posterior auricular arteries. These findings imply that the black Kenyan population has over 38% frequency of variant termination of common carotid arteries comprising trifurcation, quadrifurcation and pentafurcation which may complicate radical neck dissection, vascular surgery, carotid catheterization and selective embolization. Surgeons and radiologists should approach the common carotid bifurcation with extra caution.Keywords: Common carotid, Trifurcation, Quadrifurcation, Pentafurcation, African, Ascending Pharyngeal, Occipital, Posterior auricular arterie

ranching pattern of the left anterior descending coronary artery in a black Kenyan Population

Branching pattern of the left anterior descending coronary artery is important in explaining variations in occurrence of coronary atherosclerosis, informing management strategies for coronary heart disease and interventional cardiology. Data on African populations are, however, scarce. Since coronary heart disease is increasing in Africa, the aim of this study was to describe branching pattern of the left anterior descending coronary artery in an indigenous Kenyan population. Two hundred and eight hearts obtained during autopsy were dissected at the Department of Human Anatomy, University of Nairobi, Kenya. The entire left anterior descending coronary artery was exposed. Number of branches, pattern of termination and level of bifurcation were determined. Images of representative patterns were taken using a high resolution digital camera. Data are presented in macrographs and tables. The number of septal and diagonal branches varied between 1 and 3. Termination occurred in the posterior interventricular sulcus in 68.8% and at the apex in 23% cases. Most common mode of terminal branching was bifurcation (76.9%) followed by trifurcation (11.3%), quadrifurcation (3.4%) and pentafurcation (1.5%). Bifurcation occurred in the distal segment in 48.8% and in the proximal segment in 15% of cases. The left anterior descending coronary artery displays high variability in number of septal and diagonal branches, level of termination, mode of terminal branching and level of terminal bifurcation. These patterns may constitute risk factors for atherosclerosis and should also be acknowledged during cardiac procedures. Pre – operative ultrasound evaluation is recommended to minimize inadvertent iatrogenic injury.Keywords: Left anterior descending, branching, termination, atherosclerosi

Variant anatomy of the testicular artery among black Kenyans

Variant anatomy of the testicular artery is important for safe surgery in the retroperioneal area, and accurate diagnosis of testicular and renal disease. The pattern of origin, number, course and branching display ethnic and geographical variations. Data from black African populations and especially Eastern Africa is scarce. The objective of this study was, therefore, to describe the topography of the intraabdominal part of testicular artery in a sample of the Kenyan population. This was a descriptive crosssectional study on one hundred (100) testicular arteries at the Department of Human Anatomy, University of Nairobi. The samples were obtained from autopsy cases and cadaveric specimens. Standard midline abdominal incisions were made, flaps of the anterior abdominal wall reflected and the intestines, mesentery and pariental peritoneum retracted systematically to expose the testicular arteries. Their site and level of origin, number, course and branching were examined. Macrographs of representative variations were taken using a high resolution digital camera. The results were analysed using SPSS version 21, and are presented using macrographs and frequency tables. Thirty three (33%) of the arteries displayed a variant anatomy, with regard to their site of origin (8%), number (4%), course (14%) and branching pattern (7%). Among the 14 cases of aberrant course, five (5%) arched over the left renal vein, eight (8%) were retrocaval and one (1%) had a retroureteric course. Seven (7%) bifurcated within the abdomen. The level of origin along the aorta varied from 1 centimetre above the renal arteries to 5.5 centimetres below them while the vertebral level of origin ranged from T12 to L4. This shows that the testicular artery among Kenyans displays a high prevalence of variant anatomy characterized by origin from the accessory renal artery, high level of aortic origin, duplication, retrocaval course and intraabdominal; division. Preopertaive evaluation of renal and gonadal vasculature is recommended to minimize misdiagnosis and inadvertent injury retroperitoneal surgery

Health promotion: From malaria control to elimination

Here we reflect on the achievement of some of the diverse activities that have brought malaria under control, highlight key challenges and propose specific health promotion interventions required to move South Africa’s malaria programme from control to elimination

Anatomical features of renal artery in a black Kenyan population: Correlation with markers of atherosclerosis

Knowledge of anatomical features of the renal artery is important in prediction,  management and control of atherosclerotic renal artery stenosis. These features show population variations but data from black African populations are scarce. The aim of this study was therefore to describe the anatomical features of the renal artery in a black Kenyan population. Six hundred and ten (610) single renal arteries from 305 adult black Kenyans [206 males, 99 females; age range 22 – 79 years] were studied by dissection at Department of Human Anatomy, University of Nairobi, Kenya. Specimens with macroscopic features of stenosis and dilatation were excluded. The implantation angle, length and branching pattern were studied. These features were correlated with intima-media thickness and luminal diameter. The  latter were determined by micrometry on Eosin/hematoxylin stained 5 micron  sections obtained from the proximal segment of the renal artery. Data was analysed by SPSS version 16.0. Student’s t-test, was used to test for statistical significance at 95% confidence interval where P value of < 0.05 was taken as significant. The results are presented in a bar graph, tables and macrographs. The mean  implantation angle was 940±150 (range 580-1250). In 26.7% cases, the angle was more than 1000. Mean length was 34±1.4 mm with 21.6 % of arteries measuring ≤ 20 mm. Variant branching pattern was present in 40.5 % of cases. It comprised trifurcation (33 %), quadrifurcation (6.6 %) and pentafurcation (0.8 %). Higher implantation angle, short arteries and variant branching were associated with  statistically significant higher intima - media thickness and luminal diameter. These results suggest that higher implantation angle, shorter length and variant branching pattern constitute geometric risk factors for renal artery atherosclerosis.  Ultrasound screening for individuals with suboptimal geometric features for renal artery atherosclerosis is recommended.Keywords: anatomical risk factors, atherosclerosis, renal arter

Variations in branching pattern of external carotid artery in a black Kenyan population

Knowledge of variations in branching of external carotid artery is important to minimise inadvertent injury and confusion in identification during neck and craniofacial surgery and interventional neuroradiology. These variations show ethnic differences. Procedures in head and neck are increasing but data on these variations among black populations are scarce. This study therefore examined the branching pattern of external carotid artery in a black Kenyan population. Two hundred and twenty-four common carotid arteries of 112 black adult Kenyans were exposed by cadaveric dissection at Department of Human Anatomy, University of Nairobi, Kenya. The sternocleidomastoid muscle and body of mandible were removed and the external carotid artery and its branches exposed. The conventional pattern of branching was observed in only 41.1% of cases. The variant patterns observed were trifurcation (26.8)%, bifurcation (17.9%) and quadrifurcation (8.9%). There were 20 (5.3%) cases of early division. Linguofacial trunk was observed in 44.7% cases. Frequency of variant branching pattern of external carotid artery in the population studied is high. Interventional radiologists, vascular, craniofacial and neck surgeons should be aware of these. Preoperative sonographic evaluation of the carotid arterial system is recommended.Keywords: External carotid artery, Variation, Trifurcation, Quadrifurcation, Africa

Comparative performance of the Mbita trap, CDC light trap and the human landing catch in the sampling of Anopheles arabiensis, An. funestus and culicine species in a rice irrigation in western Kenya

BACKGROUND: Mosquitoes sampling is an important component in malaria control. However, most of the methods used have several shortcomings and hence there is a need to develop and calibrate new methods. The Mbita trap for capturing host-seeking mosquitoes was recently developed and successfully tested in Kenya. However, the Mbita trap is less effective at catching outdoor-biting Anopheles funestus and Anopheles arabiensis in Madagascar and, thus, there is need to further evaluate this trap in diverse epidemiological settings. This study reports a field evaluation of the Mbita trap in a rice irrigation scheme in Kenya METHODS: The mosquito sampling efficiency of the Mbita trap was compared to that of the CDC light trap and the human landing catch in western Kenya. Data was analysed by Bayesian regression of linear and non-linear models. RESULTS: The Mbita trap caught about 17%, 60%, and 20% of the number of An. arabiensis, An. funestus, and culicine species caught in the human landing collections respectively. There was consistency in sampling proportionality between the Mbita trap and the human landing catch for both An. arabiensis and the culicine species. For An. funestus, the Mbita trap portrayed some density-dependent sampling efficiency that suggested lowered sampling efficiency of human landing catch at low densities. The CDC light trap caught about 60%, 120%, and 552% of the number of An. arabiensis, An. funestus, and culicine species caught in the human landing collections respectively. There was consistency in the sampling proportionality between the CDC light trap and the human landing catch for both An. arabiensis and An. funestus, whereas for the culicines, there was no simple relationship between the two methods. CONCLUSIONS: The Mbita trap is less sensitive than either the human landing catch or the CDC light trap. However, for a given investment of time and money, it is likely to catch more mosquitoes over a longer (and hence more representative) period. This trap can therefore be recommended for use by community members for passive mosquito surveillance. Nonetheless, there is still a need to develop new sampling methods for some epidemiological settings. The human landing catch should be maintained as the standard reference method for use in calibrating new methods for sampling the human biting population of mosquitoes

Circulation Patterns Associated with Current and Future Rainfall over Ethiopia and South Sudan from a Convection-Permitting Model

Ethiopia and South Sudan contain several population centers and important ecosystems that depend on July–August rainfall. Here we use two models to understand current and future rainfall: the first ever pan-African numerical model of climate change with explicit convection and a parameterized model that resembles a typical regional climate model at 4.5 and 25 km horizontal grid-spacing, respectively. The explicit convection and higher resolution of the first model offer a greatly improved representation of both the frequency and intensity of rainfall, when compared to the parametrized convection model. Furthermore, only this model has success in capturing the east–west propagation of rainfall over the full diurnal cycle. Enhanced low-level westerlies were found for extremely wet days, though this response was weaker in the explicit convection model. The increased orographic detail in the explicit model resulted in the splitting of the low-level Turkana Jet core into smaller cores, and inhibited its penetration far into South Sudan. Some projected changes were found to be independent of model, such as changes in the strength of Somali and Turkana jets, as well as the shifting of Turkana jet core to lower levels. However, the explicit model end-of-century projections showed a larger and clearer decrease in wet days, accompanied by an increase in wet day intensity and extreme rainfall. This study highlights serious limitations of relying solely on simulations which parameterize convection to inform decisions in the region of South Sudan and Ethiopia

Il contributo degli esuli italiani alla riflessione sui caratteri dei totalitarismi: alcuni casi di studio

Il saggio esami la riflessione sviluppata da alcuni grandi esuli italiani sui caratteri dei totalitarism