The Role of Apparent Diffusion Coefficient Values in Glioblastoma: Differentiating Tumor Progression Versus Treatment-Related Changes.

OBJECTIVE: Glioblastoma represents the most common primary brain malignancy with a median survival of 15 months. Follow-up examinations are crucial to establish the presence of tumor recurrence, as well as treatment-associated changes such as ischemic infarction and radiation effects. Even though magnetic resonance imaging is a valuable tool, a histopathological diagnosis is often required because of imaging overlap between tumor recurrence and treatment associated changes. We set out to measure the apparent diffusion coefficient (ADC) values of the lesions in magnetic resonance imaging scans of treated glioblastoma patients to investigate if ADC values could accurately differentiate between tumor progression, radiation-related changes, and ischemic infarctions. METHODS: We evaluated ADC values among 3 groups, patients with tumor progression, radiation necrosis, and ischemic infarctions. The regions of interest were placed in the areas of greatest hypointensity among solid lesions using the ADC maps, excluding areas with necrotic, cystic, or hemorrhagic changes. The ADC values of the contralateral normal appearing white matter were also measured as the reference value for each patient. The relative ADC (rADC) values were measured for all 3 groups. Comparison between lesions and normal white matter was evaluated by Wilcoxon signed test. RESULTS: A total of 157 patients were included in the study; 49 patients classified as tumor progression, 58 patients as radiation necrosis, and 50 patients as ischemic infarctions. The mean ± SD ADC value was 752.8 ± 132.5 for tumor progression, 479.0 ± 105.2 for radiation-related changes, and 250.1 ± 57.2 for ischemic infarctions. The mean ± SD rADC value was 1.07 ± 0.22 for tumor progression, 0.66 ± 0.14 for radiation necrosis, and 0.34 ± 0.08 for ischemic infarctions. The mean rADC values were significantly higher in tumor progression, compared with both radiation necrosis and ischemic changes ( P < 0.001). CONCLUSIONS: The present study demonstrates that ADC values are a helpful tool to differentiate between tumor progression, radiation necrosis, and posttreatment ischemic changes.

Retroperitoneal Peripancreatic Ganglioneuroma Encasing the Celiac Trunk and Superior Mesenteric Artery.

A retroperitoneal ganglioneuroma is an exceptionally rare surgical entity, even more so in pancreaticoduodenal tumors. These well-differentiated neuroepithelial tumors originate in the neural crest, emerge in the sympathetic nervous system, and consist of ganglion cells and stromal Schwann cells. Generally, these tumors, despite being mostly benign, may be associated with venous or arterial vascular involvement. The symptomatology presented will depend on the mass effect due to tumor growth, and surgical excision is the only therapeutic option offered today to these patients. However, encapsulation of the main vessels represents a great surgical complexity. Various surgical approaches have been employed throughout history; however, the current preferred method is an open midline laparotomy, involving an extensive Kocher maneuver and an artery-first approach, aiming for an R0 resection of the tumor with total vascular preservation to the greatest extent possible. We present a case of an R2 resection involving a 95 mm x 85 mm retroperitoneal peripancreatic ganglioneuroma with double vascular involvement (celiac trunk and superior mesenteric artery). The procedure utilized an artery-first approach with total vascular preservation in a 17-year-old woman who had long-standing gastrointestinal symptoms due to the mass effect.

Tests and evaluation of a variable focus liquid lens for curvature wavefront sensors in astronomy.

Curvature wavefront sensors (WFSs), which obtain the wavefront aberrations from two defocused intensity images at each side of the pupil plane, have shown to be highly efficient for astronomical applications. We propose here an alternative defocusing mechanism for curvature sensors, based on an electrowetting-based variable focus liquid lens. Typically, the sampling rates of a WFS for active optics are of the order of 0.01 Hz, and the focus modulation can be done by simply moving the detector back and forth. On the other hand, adaptive optics may require speeds of up to several hundred hertz, and the modulation is then done by using a fast vibrating membrane mirror. We believe variable focus liquid lenses may be able to perform this focus modulation, reducing the overall size of the system and without the need of extra moving parts. We have done a full characterization of the Varioptic Arctic 416 liquid lens, and we have evaluated its potential performance in different curvature configurations.

Introducing the "Temporal Thumb Sign" in Pediatric Patients With New-Onset Idiopathic Seizures With and Without Elevated Cerebrospinal Fluid Opening Pressure.

BACKGROUND: Temporal lobe changes, such as anterior temporal lobe meningoceles or encephaloceles, have been documented as possible epileptogenic foci in a subset of pediatric patients with seizures. In our study, we aim to analyze a different structural change in the temporal lobe, remodeling of the posterior temporal skull base by the inferior temporal gyrus called the "temporal thumb sign" (TTS), in pediatric patients presenting with new-onset seizures with or without elevated opening pressure (OP), patients presenting with confirmed diagnosis of idiopathic intracranial hypertension (IIH) without seizure presentation, and healthy controls. METHODS: Magnetic resonance imaging scans of 163 pediatric patients were studied retrospectively for the presence of TTS. We analyzed the scans of 43 patients with elevated OP and confirmed IIH, 40 patients with elevated OP and new-onset idiopathic seizures, 40 patients with normal OP and new-onset idiopathic seizures, and 40 age- and sex-matched healthy controls. RESULTS: The TTS was detected most frequently in patients with elevated OP and seizures at 72.5% compared with patients with IIH with no seizures and patients with normal OP and seizures (32.6% and 27.5%, respectively). The TTS had a frequency of 12.5% in the control group. The TTS had the highest combination of specificity and sensitivity (72.5% and 72.5%) in patients with seizures and elevated OP compared with patients with seizures and normal OP (P value < 0.001). CONCLUSIONS: Our results suggest the Kamali "temporal thumb sign" is a novel imaging feature that may be used as a sensitive and specific imaging finding associated with seizures and elevated OP in the pediatric population.

Thermal stability analyses of human PERIOD-2 C-terminal domain using dynamic light scattering and circular dichroism.

At the molecular level, the circadian clock is regulated by a time delayed transcriptional-translational feedback loop in which the core proteins interact with each other rhythmically to drive daily biological rhythms. The C-terminal domain of a key clock protein PER2 (PER2c) plays a critically important role in the loop, not only for its interaction with the binding partner CRY proteins but also for the CRY/PER complex's translocation from the cytosol to the nucleus. Previous circular dichroism (CD) spectroscopic studies have shown that mouse PER2c (mPER2c) is less structured in solution by itself but folded into stable secondary structures upon interaction with mouse CRYs. To understand the stability and folding of human PER2c (hPER2c), we expressed and purified hPER2c. Three oligomerization forms of recombinant hPER2c were identified and thoroughly characterized through a combination of biochemical and biophysical techniques. Different to mPER2c, both thermal unfolding DLS and CD analyses suggested that all forms of hPER2c have very stable secondary structures in solution by themselves with melting temperatures higher than the physiological body temperature, indicating that hPER2c does not require CRY to fold. Furthermore, we examined the effects of EDTA, salt concentration, and a reducing agent on hPER2c folding and oligomerization. The ability of hPER2c forming oligomers reflects the potential role of hPER2c in the assembly of circadian rhythm core protein complexes.

Efectividad del fenobarbital, diazepam y antipirético para prevenir recurrencias en niños con una primera convulsión febril

El propósito de este estudio fue comparar la efectividad de estos tres tipos de tratamiento para prevenir las recurrencias de las convulsiones febriles durante el primer año posterior a la primera convulsión febril. Se trata de un trabajo prospectivo, tipo ensayo clínico controlado, abierto, no aleatorio. Se incluyeron finalmente 87 niños que consultaron al servicio de urgencias del Hospital Militar Central, por presentar una primera convulsión febril durante el período comprendido entre marzo de 1990 a junio de 1992. Los tres grupos de tratamiento se recomendaron así: fenobarbital como profilaxis continua 5 mg/Kg/día; diazepam 0,5 mg/Kg sublingual o rectal cada 12 horas en caso de presentar fiebre y acetaminofen 10 mg/Kg cada seis horas también en caso de fiebre. Presentaron recurrencias 2/29 pacientes tratados con diazepam, 9/28 niños tratados con fenobarbital y 12/30 casos que recibieron acetaminofen. Encontrándose una diferencia estadísticamente significativa (p<0.025) a favor del tratamiento con diazepam. En este trabajo no se encontró ninguna justificación para continuar recomendando la administración continua de fenobarbital en niños sanos con convulsiones febriles.

Estudio clínico de la epilepsia mioclónica juvenil

El objetivo de este trabajo es evaluar la frecuencia de presentación, características clínicas y respuesta al tratamiento en escolares y adolescentes con diagnóstico de epilepsia mioclónica juvenil. Es un estudio retrospectivo de una serie de casos de niños con epilepsia mioclónica juvenil del Servicio de Neurología Infantil del Hospital Militar Central (HMC) en el período comprendido entre el 1o. de noviembre de 1989 y el 31 de octubre de 1991. Se recopilaron 17 pacientes durante el período de tiempo evaluado, con un predominio de mujeres 12/17 casos. La distribución por edad osciló entre los ocho y los 14 años siendo más frecuente entre los ocho y los diez años. Los antecedentes familiares de epilepsia primaria fueron positivos en 30 por ciento, mioclonías asociadas a crisis tónico-clónicas generalizadas en 12 por ciento. El tratamiento instaurado con ácido valproico se realizó en 16/17 pacientes obteniéndose control de las crisis en 81 por ciento; 3/17 pacientes requirieron asociación de clobazam con ácido valproico para el control; un paciente se manejó con clobazam únicamente. La epilepsia mioclónica juvenil es el síndrome epiléptico primario más frecuente encontrado en el grupo de escolares y adolescentes de la Clínica de Epilepsia del Servicio de Neurología Infantil de HMC. La sospecha clínica de esta entidad es básica para un diagnóstico adecuado, especialmente cuando el primero o el único tipo de crisis son mioclonías matinales.