From imaging to precision: low cost and accurate determination of stereotactic coordinates for brain surgery Sapajus apella using MRI.

The capuchin monkey (Sapajus apella), a New World monkey species, exhibits prominent characteristics that make it an ideal model for neuroscience research. These characteristics include its phylogenetic traits, telencephalization coefficient, anatomical structures and pathways, genetic profile, immune responses, cognitive abilities, and complex behavioral repertoires. Traditionally, methodologies for stereotactic neurosurgery in research models have relied on the use of brain atlases. However, this approach can lead to errors due to the considerable variation in brain size and shape among individual monkeys. To address this issue, we developed a protocol for deriving individual coordinates for each monkey using a straightforward and relatively inexpensive method involving MRI imaging. Our protocol utilizes a specially designed, 3D-printed stereotactic head-holder that is safe to use with an MR magnet, non-invasive placement of fiducial markers, and post-processing with open-source software. This approach enhances MRI data visualization, improves anatomical targeting, and refines the design of neurosurgical experiments. Our technique could also prove beneficial in other areas of neuroscience research that require accurate calculation of stereotaxic coordinates. Furthermore, it could be useful for other nonhuman primate species for which brain atlases are typically unavailable.

Novel N-terminal mutation of human apolipoprotein A-I reduces self-association and impairs LCAT activation.

We have identified a novel mutation in apoA-I (serine 36 to alanine; S36A) in a human subject with severe hypoalphalipoproteinemia. The mutation is located in the N-terminal region of the protein, which has been implicated in several functions, including lipid binding and lecithin:cholesterol acyltransferase (LCAT) activity. In the present study, the S36A protein was produced recombinantly and characterized both structurally and functionally. While the helical content of the mutant protein was lower compared with wild-type (WT) apoA-I, it retained its helical character. The protein stability, measured as the resistance to guanidine-induced denaturation, decreased significantly. Interestingly, native gel electrophoresis, cross-linking, and sedimentation equilibrium analysis showed that the S36A mutant was primarily present as a monomer, notably different from the WT protein, which showed considerable oligomeric forms. Although the ability of S36A apoA-I to solubilize phosphatidylcholine vesicles and bind to lipoprotein surfaces was not altered, a significantly impaired LCAT activation compared with the WT protein was observed. These results implicate a region around S36 in apoA-I self-association, independent of the intact C terminus. Furthermore, the region around S36 in the N-terminus of human apoA-I is necessary for LCAT activation.

Reticulated platelets and thrombopoietin in schistosomiasis patients.

Schistosomiasis mansoni is a non-cirrhotic liver disease. In cirrhosis patients with portal hypertension, a decreased number of reticulated platelets associated with increased thrombopoietin serum levels were reported. We previously reported a 120/nl platelet cutoff level as a marker of clinically significant portal hypertension in schistosomiasis patients. To evaluate reticulated platelet counts and thrombopoietin serum levels (TPO) in schistosomiasis patients and correlate them with portal hypertension markers. Thirty-three schistosomiasis patients without co-morbidities were endoscopically classified as those with (n = 19) or without (n = 14) clinically significant portal hypertension. Flow cytometric determination of reticulated platelets was performed using CD41 antibody and thiazol orange. Ultrasonographic examinations were performed according to the Niamey protocol. TPO and hyaluronic acid serum levels were determined in duplicate using ELISA methods. The platelet number of 120/nl discriminates the two groups with 100% accuracy and 100% positive and negative predictive values, and correlates with spleen length and portal and splenic vein diameters. Differences in reticulated platelets and hyaluronic acid serum levels between both groups were significant (P = 0.025 and 0.012, respectively), but thrombopoietin serum levels were not (P = 0.769). Schistosomiasis patients with portal hypertension have increased reticulated platelets associated with normal TPO serum levels.

Diagnóstico prenatal de teratoma sacrococcígeo, utilidad del ultrasonido y resonancia magnética / Sacrococcygeal teratoma prenatal diagnosis, utility of ultrasound and magnetic resonance image

El teratoma sacrococcígeo (TS) es una malformación de muy baja frecuencia y de alta letalidad. El objetivo de este trabajo es presentar un caso clínico de diagnóstico prenatal de teratoma sacrococcígeo, utilizando ultrasonido y resonancia magnética. Paciente de 21 semanas de gestación es enviada para segunda opinión a nuestro centro. Realizamos examen ultrasonográfico que reveló una lesión perineal quística predominante externa de gran tamaño, con componente presacro de menor volumen y escasos vasos sanguíneos en su pared, lo que sugiere el diagnóstico de teratoma quístico. Se realiza resonancia magnética que comprueba el diagnóstico de TS quístico predominantemente externo. El resto de la evaluación anatómica y hemodinámica fue normal. Evoluciona con aumento del tamaño de la lesión, sin complicaciones maternas o fetales. A las 38 semanas de gestación, se realiza operación cesárea que comprueba diagnóstico de TS, y a las 24 horas de vida se efectúa extirpación del tumor en su totalidad con resección del cóccix y parte del sacro, con plastía del defecto remanente. El diagnóstico prenatal de TS quístico, en nuestro caso, mediante el uso de ultrasonido y resonancia magnética permite por una parte predecir una evolución favorable durante la gestación, y por otra, posibilita el manejo multidisciplinario con interrupción programada y cirugía definitiva del TS.