Abordaje posterior como tratamiento del ganglioneuroma retrorrectal, un tumor infrecuente / Posterior approach as treatment of retrorrectal ganglioneuroma, a rare tumor

Los ganglioneuromas son tumores benignos del sistema nervioso simpático, con origen en las células de la cresta neural. Forman parte del grupo de tumores neurogénicos, segundo en frecuencia en la clasificación de tumores retrorrectales. Describimos el caso de una mujer de 71 años que presenta una lesión en el espacio retrorrectal izquierdo de unos 45 X 21 X 56mm con una biopsia guiada por TC preoperatoria que descarta malignidad. Se decide exéresis de la tumoración a través de un abordaje posterior, realizando una incisión parasacrococcígea izquierda. El estudio anatomopatológico de la pieza quirúrgica describe un ganglioneuroma con bordes de resección libres. Los tumores de localización retrorrectal son infrecuentes y a pesar de no ser sintomáticos, se recomienda su exéresis. Por tanto, un correcto estudio preoperatorio para una estrategia quirúrgica adecuada es esencial. La RMN es el método diagnóstico de elección y fundamental para elegir el abordaje quirúrgico. De manera general, lesiones con límite superior por encima de S3 o con invasión locorregional de estructuras pelvianas, requerirían un aborde abdominal o en ocasiones combinado. Por tanto, una amplia exéresis del tumor es el pilar fundamental del tratamiento. La recurrencia postoperatoria y la trasformación maligna, aunque están descritas en la literatura hasta la fecha, son extraordinarias

Ganglioneuromas are benign lesions arising from sympathetic ganglion cells. They are in the neurogenic group, second in frequency in retrorectal tumors clasification. We present a case of a 71-year-old woman who presented a lesion in the left retrorectal space around 45 X 21 X 56 mm with a preoperative CT-guided biopsy that ruled out malignancy. The tumor was excised through a posterior approach, using a left parasacrococcygeal incision. Postoperative histopathologic study confirmed the lesion as a ganglioneuroma. Retrorectal tumors are uncommon and may be incidental, but their excision is recommended. Therefore, a correct preoperative study is essential. Pelvic MRI is the best imaging modality and aids surgical planning. In general, lesions with an upper limit above S3 or with locoregional invasion of pelvic structures would require an abdominal or combined approach. Therefore, a complete excision of the tumor is the mainstay of the treatment. Postoperative recurrence and malignant transformation, although described in the literature, are extraordinary

Iriomoteolides: novel chemical tools to study actin dynamics.

Despite its promising biological profile, the cellular targets of iriomoteolide-3a, a novel 15-membered macrolide isolated from Amphidinium sp., have remained unknown. A small library of non-natural iriomoteolide-3a analogues is presented here as a result of a novel, highly convergent, catalysis-based scaffold-diversification campaign, which revealed the suitable sites for chemical editing in the original core. We provide compelling experimental evidence for actin as one of iriomoteolides' primary cellular targets, establishing the ability of these secondary metabolites to inhibit cell migration, induce severe morphological changes in cells and cause a reversible cytoplasmic retraction and reduction of F-actin fibers in a time and dose dependent manner. These results are interpreted in light of the ability of iriomoteolides to stabilize F-actin filaments. Molecular dynamics simulations provide evidence for iriomoteolide-3a binding to the barbed end of G-actin. These results showcase iriomoteolides as novel and easily tunable chemical probes for the in vitro study of actin dynamics in the context of cell motility processes including cell invasion and division.

Biphasic effect of insulin on beta cell apoptosis depending on glucose deprivation.

Insulin resistant states are associated with an increase in the beta cell mass and also high levels of circulating insulin. Ultimately the beta cells undergo a failure that leads to diabetes. At this stage, a question arises if those persistent high levels of circulating insulin may contribute to beta cell damage. To address this important issue, we submitted beta cells to a prolonged effect of increasing concentrations of insulin. We observed that a prolonged effect of high levels of insulin on the presence of serum (15-24h) in glucose-deprived beta cells induced apoptosis. This apoptotic effect was both dose- and cycloheximide-dependent.

Cyclizations of enynes catalyzed by PtCl2 or other transition metal chlorides: divergent reaction pathways.

1-en-6-ynes react with alcohols or water in the presence of PtCl2 as catalyst to give carbocycles with alkoxy or hydroxy functional groups at the side chain. The reaction proceeds by anti attack of the alkene onto the (eta2-alkyne)platinum complex. The formation of the C-C and C-O bonds takes place stereoselectively by trans addition of the electrophile derived from the alkyne and the nucleophile to the double bond of the enyne. Formation of five- or six-membered carbo- or heterocycles could be obtained from 1-en-6-ynes depending on the substituents on the alkene or at the tether. Although more limited in scope, Ru(II) and Au(III) chlorides also give rise to alkoxy- or hydroxycyclization of enynes. On the basis of density functional theory (DFT) calculations, a cyclopropyl platinacarbene complex was found as the key intermediate in the process. In the presence of polar, nonnucleophilic solvents, 1-en-6-ynes are cycloisomerized with PtCl2 as catalyst. Formation of a platinacyclopentene intermediate is supported by DFT calculations. The reaction takes place by selective hydrogen abstraction of the trans-allylic substituent. Cycloisomerization of enynes containing disubstituted alkenes could be carried out using RuCl3 or Ru(AsPh3)4Cl2 in MeOH.

[Segmental motor paralysis caused by the varicella zoster virus. Clinical study and functional prognosis]. / Parálisis motora segmentaria por virus varicela-zoster. Estudio clínico y pronóstico funcional.

INTRODUCTION: Segmental motor paralysis of the limbs (SMP) complicates 2-3% of the cases of cutaneous herpes zoster. Viral invasion and inflammation of the motor neurons of the anterior horn cells by the varicella-zoster virus (VVZ) causes clinical weakness at the same time and site as the cutaneous eruption. OBJECTIVES: To analyze the clinical findings, complementary investigations and functional prognosis of patients with SMP at brachial plexus and lumbosacral levels. PATIENTS AND METHODS: We made a retrospective study of 10 patients with SMP admitted to the Hospital Universitario Gregorio Maranon de Madrid during 1989-1999, aged between 38 and 84 years (6 women, 4 men). Neurological examination was done, including muscle balance, complementary studies including microbiology (serum and CSF serology, viral PCR-ADN), neurophysiology using MNR of the spine and plexuses and functional prognosis on the NDS, NSS and RANKIN scales. RESULTS: There is a close relationship between dermatome and myotome involvement (90%). The brachial and lumbosacral plexuses were equally affected (50%). Plasma and CSF VVZ serology was positive in 50% of the cases, permitting diagnosis of a patient with no cutaneous lesions (zoster sine herpete). Denervation of the myotomes involved and the paraspinal muscles was shown on neurophysiological studies. In most cases there was functional improvement, with complete functional recovery in 80% of the cases after 12 months. CONCLUSIONS: VVZ should be considered amongst the aetiologies of SMP, even in the absence of cutaneous lesions (zoster sine herpete). The SMP coincides in time and place with the dermatome lesions. In most patients there is complete functional recovery within 12 months.

Parálisis motora segmentaria por virus varicela-zoster. Estudio clínico y pronóstico funcional / Segmental motor paralysis due to varicella-zoster virus. A clinical and functional prognosis study

Introducción. La parálisis motora segmentaria en miembros (PMS) complica el 2-3 por ciento de los casos de herpes zoster cutáneo.La invasión vírica y la inflamación de las motoneuronas del asta anterior por el virus varicela-zoster (VVZ) provoca un cuadro de debilidad coincidente en tiempo y distribución con la erupción cutánea.Objetivos. Analizar los hallazgos clínicos, exploraciones complementarias y pronóstico funcional en los pacientes con PMS en plexos braquial y lumbosacro. Pacientes y métodos. Se han estudiado retrospectivamente 10 pacientes afectados de PMS, ingresados en el Hospital General Universitario Gregorio Marañón de Madrid (España) entre 1989 y 1999, con edades comprendidas entre 34-84 años (6 mujeres y 4 varones). Se realizó exploración neurológica con balance muscular, estudios complementarios con microbiología (serología en suero y líquido cefalorraquídeo (LCR), reacción en cadena de la polimerasa-ADN vírico), neurofisiología, neuroimagen con resonancia magnética espinal y de plexos, y pronóstico funcional mediante las escalas Neurological Disability Scale (NDS), Neurological Symptom Score (NSS) y Rankin. Resultados. Existió una estrecha relación entre la afectación dermatómica y la miotómica (90 por ciento). La afectación fue proporcional en plexos braquial y lumbosacro (50 por ciento). La serología para VVZ fue positiva en suero y LCR en el 50 por ciento de los casos; este hecho permitió el diagnóstico en un paciente sin lesiones cutáneas (zoster sine herpete). En el estudio neurofisiológico existía desnervación en miotomas afectos y musculatura paraespinal. La evolución funcional fue favorable en la mayoría de los pacientes, con recuperación funcional completa en el 80 por ciento de los casos en 12 meses.Conclusiones. Debemos considerar al VVZ dentro de las etiologías de la PMS, incluso en ausencia de lesiones cutáneas (zoster sine herpete). La PMS coincide en tiempo y localización con las lesiones dermatómicas. La recuperación funcional es completa en la mayoría de los pacientes al cabo de 12 meses (AU)

[Acute phenytoin poisoning secondary to an interaction with ticlopidine]. / Intoxicación aguda por fenitoína secundaria a interacción con ticlopidina.

INTRODUCTION: Ticlopidine and phenytoin are two drugs which are widely used in everyday clinical practice, the first as a platelet anti-aggregant and the second as an anti-epileptic agent. Their association is not uncommon, since there is a high incidence of epileptic crises of vascular origin in adults. CLINICAL CASE: We present the case of a 77 year old man who had been treated for twenty years with phenytoin for partial crises secondary to a left frontal hematoma. He then followed treatment with ticlopidine for a femoropopliteal bypass, and the dose was later increased because of a vertebro-basilar ictus. On both occasions he presented with ataxia, dysarthria and nausea due to phenytoin intoxication. The blood levels of this drug were above the therapeutic level. The symptoms disappeared and the patient returned to normal after reduction of the dose of phenytoin and suspending treatment with ticlopidine. DISCUSSION: The mechanism of action of ticlopidine at cytochrome P450 level, inhibiting the metabolic clearance of phenytoin, was responsible for this interaction. We have found only three other cases of interaction between these drugs in the literature, and ours is the first to be published in Spain. CONCLUSION: We emphasize the importance of checking plasma phenytoin levels when starting treatment with ticlopidine, since it may be necessary to reduce the dose of phenytoin.