Regression and simulation models for human and baboon brain parameters / Modelo regresivo y simulación para los parámetros cerebrales humanos y del babuino

The variations in morphometric parameter of mammalian brains may be influenced by process of functional complexity, evolution and adaptation. Comparative analysis of linear measurements of cerebrum in the human and baboon has shown morphometric differences. In the present study linear measurements from human and baboon cerebrum (n=10 each) were used to predict various values for human and baboon brain and body parameters through multiple regression models. The average brain weights were found to be 2.08 percent and 0.84 percent of the body weights for humans and baboons respectively. The elasticity of regression models revealed that unit percentage increase in Occipital-Frontal (OF) distance would increase the human brain weight by 66.19 percent, while the baboon brain weight would increase by 7.63 percent. The unit percentage increase in the Height of Temporal Lobe (HTL) would increase the human brain weight by 16.28 percent, while the baboon brain weight would increase by only 0.28 percent. Unit percentage increase in Frontal-Temporal (FT) distance would decrease the human and baboon brain weights by 14.04 percent and 0.46 percent respectively. Inter-species values were also predicted through simulation techniques by using the ratios of model parameters with application of programming language Python. The OF, FT and HTL values for human were found to be 2.01 times, 1.55 times and 1.91 times respectively to that of baboon.

Las variaciones en los parámetros morfométricos del cerebro de los mamíferos pueden estar influenciadas por el proceso de complejidad funcional de la evolución y adaptación. Análisis comparativo de las mediciones lineales del cerebro en el humano y babuino han puesto de manifiesto las diferencias morfométricas. En este estudio las mediciones lineales del cerebro humano y babuinos (n = 10 cada uno) fueron utilizados para predecir los valores distintivos para el cerebro de humanos y monos babuinos y los parámetros del cuerpo a través de modelos de regresión múltiple. El peso medio del cerebro resultó ser 2,08 por ciento y 0,84 por ciento del peso corporal de los seres humanos y los babuinos, respectivamente. La elasticidad de los modelos de regresión reveló que el aumento de una unidad porcentual en la distancia occipital-frontal (DE) aumentaría el peso del cerebro humano en 66,19 por ciento, mientras que el peso del cerebro babuino se incrementaría en 7,63 por ciento. El porcentaje de aumento en la altura de lóbulo temporal (HTL) aumentaría el peso del cerebro humano en 16,28 por ciento, mientras que el peso del cerebro babuino aumentaría en sólo el 0,28 por ciento. Si aumenta la distancia frontal-temporal (FT) se reduciría el peso del cerebro humano y babuinos en 14,04 por ciento y 0,46 por ciento, respectivamente. También se prevéen valores entre las especies a través de técnicas de simulación, mediante el uso de proporciones de los parámetros del modelo con la aplicación del lenguaje de programación Python. Los valores humanos de DE, FT y HTL resultaron ser 2,01, 1,55 y 1,91 veces, respectivamente con respecto a la de los babuinos.

Position and blood supply of the carotid body in a Kenyan population / Posición y suministro sanguíneo del cuerpo carotídeo en una población de Kenia

Position and source of blood supply to the human carotid body displays population variations. These data are important during surgical procedures and diagnostic imaging in the neck but are only scarcely reported and altogether missing for the Kenyan population. The aim of this study was to describe the position and blood supply of the carotid body in a Kenyan population. A descriptive cross-sectional study at the Department of Human Anatomy, University of Nairobi, was designed. 136 common carotid arteries and their bifurcations were exposed by gross dissection. The carotid body was identified as a small oval structure embedded in the blood vessel adventitia. Position and source of blood supply were photographed. Data are presented by tables and macrographs. 138 carotid bodies were identified. Commonest position was carotid bifurcation (75.4 percent) followed by external carotid artery (10.2 percent), internal carotid artery (7.2 percent) and ascending pharyngeal artery (7.2 percent). Sources of arterial blood supply included the carotid bifurcation (51.4 percent), ascending pharyngeal (21.0 percent), external carotid (17.4 percent) and internal carotid (10.2 percent) arteries. Position and blood supply of the carotid body in the Kenyan population displays a different profile of variations from those described in other populations. Neck surgeons should be aware of these to avoid inadvertent injury.

La posición y la fuente de suministro sanguíneo del cuerpo carotídeo humano muestra variaciones en la población. Estos datos son importantes durante los procedimientos quirúrgicos y de diagnóstico por imagen en el cuello, pero son poco informados e inclusive faltan por completo en la población de Kenia. El objetivo de este estudio fue describir la posición y el aporte sanguíneo del cuerpo carotídeo en una población de Kenia. Se diseñó un estudio descriptivo de corte transversal en el Departamento de Anatomía Humana de la Universidad de Nairobi. 136 arterias carótidas comunes y sus bifurcaciones fueron expuestas mediante disección simple. El cuerpo carotídeo fue identificado como una pequeña estructura oval ubicada en la adventicia del vaso sanguíneo. La posición y la fuente de suministro sanguíneo fueron fotografiados. Los datos obtenidos fueron presentados en las tablas y fotomacrografías. 138 cuerpos carotídeos fueron identificados. La posición más frecuente fue la bifurcación carotídea (75,4 por ciento), seguida de la arteria carótida externa (10,2 por ciento), arteria carótida interna (7,2 por ciento) y la arteria faríngea ascendente (7,2 por ciento). Las fuentes de suministro sanguíneo arterial incluyeron la bifurcación carotídea (51,4 por ciento), arteria faríngea ascendente (21,0 por ciento), arteria carótida externa (17,4 por ciento) y arterias carótidas internas (10,2 por ciento). La posición y el suministro sanguíneo del cuerpo carotídeo en la población de Kenia muestra un perfil de variaciones diferente a las descritos en otras poblaciones. Los cirujanos de cuello deben conocer estas variaciones para así evitar lesiones accidentales.

Comparative functional structure of the olfactory mucosa in the domestic dog and sheep.

Olfactory acuity differs among animal species depending on age and dependence on smell. However, the attendant functional anatomy has not been elucidated. We sought to determine the functional structure of the olfactory mucosa in suckling and adult dog and sheep. Mucosal samples harvested from ethmoturbinates were analyzed qualitatively and quantitatively. In both species, the olfactory mucosa comprised olfactory, supporting and basal cells, and a lamina propria containing bundles of olfactory cell axons, Bowman's glands and vascular elements. The olfactory cells terminated apically with an expanded knob, from which cilia projected in a radial fashion from its base and in form of a tuft from its apex in the dog and the sheep respectively. Olfactory cilia per knob were more numerous in the dog (19 ± 3) compared to the sheep (7 ± 2) (p<0.05). In the dog, axonal bundles exhibited one to two centrally located capillaries and the bundles were of greater diameters (73.3 ± 10.3 µm) than those of the sheep (50.6 ± 6.8 µm), which had no capillaries. From suckling to adulthood in the dog, the packing density of the olfactory and supporting cells increased by 22.5% and 12.6% respectively. Surprisingly in the sheep, the density of the olfactory cells decreased by 26.2% while that of the supportive cells showed no change. Overall epithelial thickness reached 72.5 ± 2.9 µm in the dog and 56.8 ± 3.1 µm in the sheep. These observations suggest that the mucosa is better structurally refined during maturation in the dog than in the sheep.

Anatomy and prevalence of atlas vertebrae bridges in a Kenyan population: An osteological study.

Atlas bridges are bony outgrowths over the third segment of the vertebral artery. They may exist as incipient, incomplete, or complete bridges, converting the groove into a deep sulcus, incomplete, or complete foramen respectively. These bridges and their associated foramina display bilateral and sex differences in their prevalence and type. Occurrence of these bridges may predispose to vertebrobasilar insufficiency and Barre-Lieou syndrome. The coexistence of lateral and posterior bridges as well as side predilection is not clear in either sex. Their relative occurrence may also point to some evolutionary patterns. We studied the prevalence, side predilection, coexistence, and anatomical features of atlas bridges using 102 dry atlases (49 males and 53 females) obtained from the osteology department of the National Museums of Kenya. Complete posterior bridges occurred in 14.7% and 13.7% on the right and left sides, respectively. A lateral bridge was found in 3.9% of cases on the right side only. There was positive correlation in the coexistence of the bridges. A retrotransverse foramen was found in 13% of cases. This study has found that posterior and lateral atlas bridges occur in association especially on the right side. Complete bridges were more prevalent in females and were more often present on the right side. This pattern seems to mirror the sexual predilection of vertebral artery compression syndromes. Gender roles may have an influence on the occurrence of these bridges and therefore the syndromes as well.

Course of the hepatic inferior vena cava in a Kenyan population.

The course of the hepatic inferior vena cava (HIVC) has a wide range of variations which are relevant in hepato-vascular surgery and liver transplantation. Eighty livers were studied for hepatic course and axial orientation of the HIVC. The HIVC was found to run in an incomplete tunnel in 43.8% of the cases (n = 35), complete tunnel in 32.5% of the cases (n = 26) while in the rest, it was contained in a shallow groove on the retrohepatic surface. It assumed an oblique course in relation to the longitudinal axis of the liver in 60% of the cases (n = 48). The findings of this study vary to a wide range from those reported previously, and call for extra caution during surgical operations involving the HIVC region.