Development of an experimental model of neurocysticercosis-induced hydrocephalus. Pilot study

ABSTRACT PURPOSE: To develop an experimental model of neurocysticercosis-induced hydrocephalus METHODS: There were used 17 rats. Ten animals were inoculated with Taenia crassiceps cysts into the subarachnoid. Five animals were injected with 0.1ml of 25% kaolin (a standard solution for the development of experimental hydrocephalus) and two animals were injected with saline. Magnetic resonance imaging (MRI) was used to evaluate enlargement of the ventricles after one or three months of inoculation. Volumetric study was used to quantify the ventricle enlargement. RESULTS: Seven of the 10 animals in the cyst group developed hydrocephalus, two of them within one month and five within three months after inoculation. Three of the five animals in the kaolin group had hydrocephalus and none in the saline group. Ventricle volumes were significantly higher in the 3-months MRI cyst subgroup than in the 1-month cyst subgroup. Differences between cyst subgroups and kaolin group did not reach statistical significance. CONCLUSION: The developed model may reproduce the human condition of neurocysticercosis-related hydrocephalus, which exhibits a slowly progressive chronic course.

Changes caused by hidrocephalus, induced by kaolin, in the corpus callosum of adult dogs / Alterações causadas pela hidrocefalia, induzida por caulim, no corpo caloso de cães adultos

PURPOSE: To analyze the ventricular enlargement and myelination of the corpus callosum in adult dogs after four and eight weeks of kaolin-induction of hydrocephalus. METHODS: 36 dogs were randomly divided into 3 groups: 1 - without hydrocephalus, 2 - kaolin-induction of hydrocephalus until the fourth week, and 3 - kaolin-induction of hydrocephalus until the eighth week. Ventricular ratios and volumes were calculated using magnetic resonance images, and myelination of the corpus callosum were histologically evaluated using solocromo-cianin stain. RESULTS: Radiological hydrocephalus was observed in 93.75 percent and overall mortality was 38.4 percent. Ventricular volumes and ratios were higher in groups 2 and 3 compared to group 1 and similar when measures in the fourth and eighth weeks were compared in the group 3. Indices of luminescence in the knee and in the splenium of the corpus callosum were higher in group 2 than in group 1 indicating that there was loss of myelin in group 2, and similar in groups 1 and 3, showing a tendency to remyelination after 8 weeks. CONCLUSION: The corpus callosum of dogs with kaolin-induced hydrocephalus responds with demyelination of the knee and splenium by the fourth week with a tendency to remyelination by the eighth week.

OBJETIVO: Analisar a dilatação ventricular e a mielinização do corpo caloso em cães adultos após quatro e oito semanas da indução de hidrocefalia por caulin. MÉTODOS: 36 cães foram aleatoriamente divididos em 3 grupos: 1- sem hidrocefalia, 2- quatro semanas de hidrocefalia induzida por caulin, 3- oito semanas de hidrocefalia induzida por caulin. As razões e volumes ventriculares foram calculados utilizando imagens de ressonância magnética, e, a mielinização do corpo caloso por estudo histológico (coloração com solocromo- cianina). RESULTADOS: Hidrocefalia foi observada radiologicamente em 93,75 por cento e a mortalidade global foi de 38,4 por cento. Os volumes e as razões ventriculares foram maiores nos grupos 2 e 3 em relação ao grupo 1 e semelhantes nas quarta e oitava semanas no grupo 3. Índices de luminescência no joelho e no esplênio do corpo caloso foram maiores no grupo 2 em relação ao grupo 1, indicando que houve perda de mielina no grupo 2, e semelhantes nos grupos 1 e 3, mostrando uma tendência à remielinização em torno de 8 semanas. CONCLUSÃO: O corpo caloso de cães com hidrocefalia induzida por caulin responde com desmielinização no joelho e esplênio em torno de quatro semanas com tendência à remielinização em torno da oitava semana.

Low Molecular Weight Heparin Treatment in Pregnant Women with a Mechanical Heart Valve Prosthesis

No definitive recommendation is available concerning optimal antithrombotic therapy in pregnant women with a mechanical heart valve. The purpose of the current study was to evaluate the clinical results of nadroparin treatment with respect to pregnancy outcome and maternal complications. From 1997 to 2005, 31 pregnancies were reviewed in 25 women. Nadroparin (7,500 U, twice daily) was used in 23 pregnancies between 6 and 12 weeks of gestation and close-to-term only, and coumarin derivatives were used with aspirin at other times. Eight pregnant women treated with coumarin derivatives throughout pregnancy were compared to evaluate the safety and efficacy of nadroparin. No maternal death or bleeding complication occurred in either of the two groups, and frequencies of maternal thromboembolism including valve thrombosis (8.7% vs. 12.5%, p>0.05) were similar. However, the frequencies of live born (91.3% vs. 50%, p=0.01) and healthy babies (90.4% vs. 25%, p<0.01) were significantly higher, and the fetal loss rate was significantly lower (8.7% vs. 50%, p=0.01) in the nadroparin-treated group. Regarding the efficacy and safety of antithrombotic treatment in pregnant women with prosthetic heart valves, nadroparin treatment during the first trimester is an acceptable regimen and produces better results than coumarin derivatives.

Morphometry of mitochondria in the choroidal ependyma of hydrocephalic guineapigs.

Fifteen young guineapigs were made hydrocephalic by intracisternal injection of kaolin and 16 guineapigs were used as control. Volume, number and surface areas of both the outer and inner membranes of the mitochondria of the choroidal ependyma of these animals were studied, using a coherent multipurpose test system. Volume, number and surface area of the outer membrane of the mitochondria did not show any significant difference between the two groups. However, surface area of the inner membrane of the mitochondria including cristae showed a significant decrease in the hydrocephalic animals. This reduction in the surface area could probably be attributed to the reduced activity of the choroidal ependymal cells in obstructive hydrocephalus.