Shear-induced detachment of biofilms from hollow fiber silicone membranes.

A suite of techniques was utilized to evaluate the correlation between biofilm physiology, fluid-induced shear stress, and detachment in hollow fiber membrane aerated bioreactors. Two monoculture species biofilms were grown on silicone fibers in a hollow fiber membrane aerated bioreactors (HfMBR) to assess detachment under laminar fluid flow conditions. Both physiology (biofilm thickness and roughness) and nutrient mass transport data indicated the presence of a steady state mature biofilm after 3 weeks of development. Surface shear stress proved to be an important parameter for predicting passive detachment for the two biofilms. The average shear stress at the surface of Nitrosomonas europaea biofilms (54.5 ± 3.2 mPa) was approximately 20% higher than for Pseudomonas aeruginosa biofilms (45.8 ± 7.7 mPa), resulting in higher biomass detachment. No significant difference in shear stress was measured between immature and mature biofilms of the same species. There was a significant difference in detached biomass for immature vs. mature biofilms in both species. However, there was no difference in detachment rate between the two species.

Juvenile Huntington disease: CT and MR features.

PURPOSE: To describe the clinical and radiologic manifestations of juvenile Huntington disease and to determine whether adult imaging criteria for Huntington disease are helpful for pediatric patients. METHODS: Six patients (3 to 18 years of age; mean age, 9.8 +/- 5.6 years; 3 female, 3 male) with juvenile Huntington disease were studied with CT (n = 6) and/or MR (n = 3). CT and MR studies were evaluated for frontal horn distance/intercaudate distance and bicaudate ratios, which were compared with those of 24 age-matched healthy children and 12 age-matched patients with Leigh (n = 9) or Wilson (n = 3) disease. RESULTS: Atrophy of the caudate nuclei was identified in all Huntington patients. The frontal horn distance/intercaudate distance (1.64 +/- 0.39) and bicaudate (0.205 +/- 0.060) ratios of the patients with juvenile Huntington disease were found to be significantly different from those of healthy children and that of those patients with Leigh/Wilson disease. The 3 patients with Huntington disease who underwent MR evaluation were noted to have increased proton density- and T2-weighted signal in the caudate nuclei and putamina. CONCLUSION: As in adult patients, the use of frontal horn distance/intercaudate distance and bicaudate ratios are helpful for the diagnosis of Huntington disease in pediatric patients. On MR, increased proton density- and T2-weighted signal in the atrophic caudate nuclei and putamina are additional features of juvenile Huntington disease.

Diffuse hepatic hemangiomas: percutaneous transcatheter embolization with detachable silicone balloons.

Two infants with severe congestive cardiac failure secondary to diffuse hepatic hemangiomas were treated by percutaneous transcatheter embolization of the hepatic arteries using detachable silicone balloons. One infant experienced dramatic improvement of the cardiac failure and showed no impairment of hepatic function. The other infant remained in a low cardiac output state following the procedure and developed acute hepatic and renal failure followed by generalized sepsis and death. Autopsy examination revealed massive hepatic hemangioendothelioma as well as areas of necrotic and viable liver parenchyma. A review of reported patients with hepatic hemangiomas treated by hepatic artery ligation or embolization showed no others who had hepatic failure. These techniques were curative in 14 of 18 patients (78%), an improvement compared with the results of other available methods of therapy.

Conventional metrizamide myelography (MM) and computed tomographic metrizamide myelography (CTMM) in scoliosis. A comparative study.

A retrospective examination was performed to assess the accuracy of metrizamide myelography (MM) and computed tomographic metrizamide myelography (CTMM) in scoliosis. Of 81 consecutive scoliotic children studied by myelography, 30 had only MM while the remaining 51 had CTMM immediately afterward. CTMM added essential diagnostic information in 13 cases of dysraphism and 4 cases of idiopathic scoliosis; in the remaining cases, both methods gave the same information. The authors conclude that in patients with severe scoliosis, dysraphism, and scoliosis with localized neurological disturbances, CTMM should always be added to MM or be the only examination; while in idiopathic scoliosis with vague neurological disturbances a survey of the entire spine is essential, preferably with MM.