Melanocitoma meníngeo del ángulo pontocerebeloso: claves imagenológicas para su abordaje / Cerebellopontine meningeal melanocytoma: keys for imaging diagnostic approach

Resumen: Las lesiones del ángulo pontocerebeloso (APC) representan el 6 al 10% de las neoplasias intracraneales, siendo los schwannomas vestibulares y meningiomas los más comunes. Sin embargo, hasta el 15% pueden ser otras lesiones, entre ellas las derivadas a partir de restos de células melanocíticas presentes en las leptomeninges. El diagnóstico diferencial de las patologías tumorales del APC es extenso, siempre teniendo en cuenta las lesiones más comunes. Sin embargo, cuando las características radiológicas no son las esperadas, el enfoque debe orientarse hacia las lesiones inusuales, poniendo en contexto las diferentes estirpes celulares que pueden dar origen a las neoplasias en esta localización, como las neoplasias melanocíticas. Se presenta el caso de un masculino de 74 años con síndrome cerebeloso de tórpida evolución, al cual se le realiza RM de cerebro contrastada, identificando una lesión de base dural en el APC izquierdo, con hiperintensidad de señal en T1 e hipointensidad en T2, atípico para las lesiones más comunes en esta región, que sugiere su contenido melanocítico.

Abstract: Cerebellopontine angle tumors (CPA) represent approximately 6 to 10% of intracranial tumors. Vestibular Schwannomas and meningiomas are the most common, however up to 15% can be of other origin, including from melanocytes derived from the neural crest. The differential diagnosis of CPA pathologies is extensive, always taking into account the most common ones. However, if the radiological characteristics are not the expected, the approach should be directed towards unusual lesions, putting into context the different cell lines that can give rise to the neoplasm at this location, such as melanotic neoplasms. We present a case of a 74-year-old male, who presented with a cerebellar syndrome. Due to an atypical clinical evolution, a contrast enhanced head MRI was performed, revealing a dural based tumor on the left CPA, which was hyperintense on T1 and hypointense on T2 weighted sequences, which is not expected from the common lesions at this region and suggested it's melanotic content.

Resistive switching control for conductive Si-nanocrystals embedded in Si/SiO2 multilayers.

In this paper, we report on the enhanced control of resistive switching in multilayer Si/SiO2 structures, which permit the formation of Si nanocrystals with a typical size of 5.88 nm and overall good shape homogeneity. The deposition of a different number of Si and SiO2 bilayers (6, 8 and 10) allowed control of SET/RESET voltages in negative bias ranges 4.5-10 V and 6.3-13 V for six- and ten-bilayer devices, respectively. The corresponding resistance ratio between ON/OFF states varied in the ranges 107-105 for the aforementioned number of bilayers. Based on the result of XPS measurements, we suggest that the resistive switching in the studied system occurs due to the formation and annihilation of Si-Si and Si-O bonds, which serve as conductive pathways and isolating material, respectively.

Polymorphism rs2073618 of the TNFRSF11B (OPG) Gene and Bone Mineral Density in Mexican Women with Rheumatoid Arthritis.

Osteoporosis (OP) is highly prevalent in rheumatoid arthritis (RA) and is influenced by genetic factors. Single-nucleotide polymorphism (SNP) rs2073618 in the TNFRSF11B osteoprotegerin (OPG) gene has been related to postmenopausal OP although, to date, no information has been described concerning whether this polymorphism is implied in abnormalities of bone mineral density (BMD) in RA. We evaluated, in a case-control study performed in Mexican-Mestizo women with RA, whether SNP rs2073618 in the TNFRSF11B gene is associated with a decrease in BMD. RA patients were classified as follows: (1) low BMD and (2) normal BMD. All patients were genotyped for the rs2073618 polymorphism by PCR-RFLP. The frequency of low BMD was 74.4%. Higher age was observed in RA with low BMD versus normal BMD (62 and 54 years, resp.; p < 0.001). Worse functioning and lower BMI were observed in RA with low BMD (p = 0.003 and p = 0.002, resp.). We found similar genotype frequencies in RA with low BMD versus RA with normal BMD (GG genotype 71% versus 64.4%, GC 26% versus 33%, and CC 3% versus 2.2%, resp.; p = 0.6). We concluded that in Mexican-Mestizo female patients with RA, the rs2073618 polymorphism of the TNRFS11B gene is not associated with low BMD.

[Elbow dislocation]. / Luxación de codo.

Elbow dislocation is the most frequent dislocation in the upper limb after shoulder dislocation. Closed reduction is feasible in outpatient care when there is no associated fracture. A review is presented of the different reduction procedures.

Utilidad del índice de presión arterial tobillo-tobillo en pacientes con trauma en extremidad inferior y signos blandos de lesión vascular / Significance and utility of the ankle-ankle systolic pressure index in inferior limb trauma patients and soft signs of vascular injury

Objetivos: Establecer la utilidad del índice de presión arterial tobillo-tobillo (ITT) en los pacientes con trauma de extremidades inferiores y signos blandos de lesión vascular en términos de sensibilidad, especificidad y valores predictivos según el mejor punto de corte detectado. Material y método: Se incluyeron 120 pacientes con trauma en extremidades inferiores y signos blandos de lesión vascular que ingresaron al Hospital Universitario de Santander (Bucaramanga, Colombia) durante los años 2012 a 2015, a los cuales se les calculó el índice tobillo-brazo (ITB) e ITT. Resultados: Un total de 21 (17,5%) pacientes tuvieron ITB menor a 0,9 al ingreso, los cuales fueron llevados a intervención quirúrgica inmediata, encontrando lesión vascular; 2 (1,6%) pacientes tuvieron ITB menor a 0,9 en el control realizado a las 6 h, los cuales también fueron llevados a intervención quirúrgica, encontrando lesión vascular. Por tanto, se encontraron 23 pacientes con lesión vascular. Las curvas ROC tanto de ITB como de ITT señalan que ambas tienen un muy buen desempeño para diagnosticar las lesiones vasculares en pacientes con signos blandos cuando se emplean una única vez. En ambos casos, el punto de corte propuesto tradicionalmente de 0,90 tiene una capacidad discriminatoria adecuada, con sensibilidad de 91% (IC 95%: 0,71-0,98), especificidad de 100% (IC 95%: 0,96-1,0), valor predictivo positivo de 100% (IC 95%: 0,83-1,0) y valor predictivo negativo de 97% (IC 95%: 0,92-0,99). Conclusión. El índice tobillo-tobillo (ITT) permite descartar lesión vascular en el paciente con trauma en extremidades inferiores y signos blandos.

Objectives: We pretend to establish the utility of the ankle-ankle systolic pressure index (AAI) in patients with trauma in the inferior limbs and soft signs of vascular injury describing its sensitivity, specificity and predictive values according to the best cut-off point. Material and method: The cohort included 120 patients with trauma in the inferior limbs and soft signs of vascular injury who attended the University Hospital of Santander (Bucaramanga, Colombia) over a period of 4 years (2012-2015). Results: 21 (17.5%) patients had an ankle brachial pressure index (ABI) < .9 at the admission and they received immediately surgical management, finding vascular injury in the operating room; 2 (1.6%) patients had an ABI < .9 in the 6 h monitoring control and they also received surgical management finding vascular injury. Therefore, we found 23 patients with vascular injury. The ROC curves for the ABI and AAI show that they both have a good achievement for the diagnosis of vascular injury in patients with soft signs when they were used one time. In both cases, the traditionally point of .90 has a good discriminatory capacity with a sensitivity of 91% (95% CI: .71-.98), specificity of 100% (95% CI: .96-1.0), positive predictive value of 100% (95% CI: .83-1.0) and negative predictive value of 97% (95% CI: .92-.99). Conclusion. The ankle-ankle systolic pressure index (AAI) allows to rule out vascular injury in the patient with trauma in the inferior limbs and soft signs.

Association between -174G/C and -572G/C interleukin 6 gene polymorphisms and severe radiographic damage to the hands of Mexican patients with rheumatoid arthritis: a preliminary report.

Several interleukin 6 gene (IL6) polymorphisms are implicated in susceptibility to rheumatoid arthritis (RA). It has not yet been established with certainty if these polymorphisms are associated with the severe radiographic damage observed in some RA patients, particularly those with the development of joint bone ankylosis (JBA). The objective of the present study was to evaluate the association between severe radiographic damage in hands and the -174G/C and -572G/C IL6 polymorphisms in Mexican Mestizo people with RA. Mestizo adults with RA and long disease duration (>5 years) were classified into two groups according to the radiographic damage in their hands: a) severe radiographic damage (JBA and/or joint bone subluxations) and b) mild or moderate radiographic damage. We compared the differences in genotype and allele frequencies of -174G/C and -572G/C IL6 polymorphisms (genotyped using polymerase chain reaction-restriction fragment length polymorphism) between these two groups. Our findings indicated that the -174G/C polymorphism of IL6 is associated with severe joint radiographic damage [maximum likelihood odds ratios (MLE_OR): 8.03; 95%CI 1.22-187.06; P = 0.03], whereas the -572G/C polymorphism of IL6 exhibited no such association (MLE_OR: 1.5; 95%CI 0.52-4.5; P = 0.44). Higher anti-cyclic citrullinated peptide antibody levels were associated with more severe joint radiographic damage (P = 0.04). We conclude that there is a relevant association between the -174G/C IL6 polymorphism and severe radiographic damage. Future studies in other populations are required to confirm our findings.

The -174G/C Interleukin-6 Gene Promoter Polymorphism as a Genetic Marker of Differences in Therapeutic Response to Methotrexate and Leflunomide in Rheumatoid Arthritis.

Objective. To evaluate the association of -174G/C IL-6 polymorphism with failure in therapeutic response to methotrexate (MTX) or leflunomide (LEF). This prospective, observational cohort included 96 Mexican-Mestizo patients with moderate or severe rheumatoid arthritis (RA), initiating MTX or LEF, genotyped for IL-6 -174G/C polymorphism by PCR-RFLP. Therapeutic response was strictly defined: only if patients achieved remission or low disease activity (DAS-28 < 3.2). Results. Patients with MTX or LEF had significant decrement in DAS-28 (p < 0.001); nevertheless, only 14% and 12.5% achieved DAS-28 < 3.2 at 3 and 6 months. After 6 months with any of these drugs the -174G/G genotype carriers (56%) had higher risk of therapeutic failure compared with GC (RR: 1.19, 95% CI: 1.07-1.56). By analyzing each drug separately, after 6 months with LEF, GG genotype confers higher risk of therapeutic failure than GC (RR = 1.56; 95% CI = 1.05-2.3; p = 0.003), or CC (RR = 1.83; 95% CI = 1.07-3.14; p = 0.001). This risk was also observed in the dominant model (RR = 1.33; 95% CI = 1.03-1.72; p = 0.02). Instead, in patients receiving MTX no genotype was predictor of therapeutic failure. We concluded that IL-6 -174G/G genotype confers higher risk of failure in therapeutic response to LEF in Mexicans and if confirmed in other populations this can be used as promissory genetic marker to differentiate risk of therapeutic failure to LEF.