Mycotic carotid aneurysm.

Mycotic aneurysms of the extracranial internal carotid artery are rare; they usually appear as an enlarging pulsatile neck mass with associated pain, tenderness, and fever. This case report illustrates the need for prompt diagnosis and urgent surgical intervention. The most common organisms found with these aneurysms have been Staphylococcus aureus and Streptococcus pyogenes. We report a case of a mycotic internal carotid artery aneurysm resulting from Salmonella enteritidis. A 20-year review of both the foreign and English language literature revealed only one other case of a mycotic carotid aneurysm resulting from Salmonella infection. The cornerstone of therapy in the past had been proximal ligation. More recently, primary reconstructive procedures with either an end-to-end anastomosis or an interposition vein graft have been described. The present case was managed with an end-to-end technique with the use of a Pruitt-Inahara shunt.

Model studies on distributions of blood cells at microvascular bifurcations.

To model the flow behavior of white and red blood cells at microvascular branch points, the distribution of neutrally buoyant spherical and disk-shaped particles at a symmetric T bifurcation was investigated for low Reynolds number flows (0.01-0.1). The particle distribution was represented by the fractional particle flux to a daughter branch as a function of the fractional volumetric bulk flow to the same branch. Particle-to-tube diameter ratios of 0.32-0.79 were studied for the spherical particles and 0.4-0.8 for the disks. As the particle dimensions approach that of the tube, the relation between the fractional particle flux and fractional bulk flow changes from a linear relation of unity slope to a nonlinear S-shaped curve. Measurements of the flow divider at the entrance to the bifurcation and the eccentricity distributions for the spheres and disks were used to develop a model that permits prediction of the observed particle distributions. These results can be used to interpret the distribution of white and red blood cells in microvascular bifurcations with dimensions close to the cell size.