Faculty Bibliography

Many neurons in the mammalian central nervous system communicate through electrical synapses, defined here as gap junction-mediated connections. Electrical synapses are reciprocal pathways for ionic current and small organic molecules. They are often strong enough to mediate close synchronization of subthreshold and spiking activity among clusters of neurons. The most thoroughly studied electrical synapses occur between excitatory projection neurons of the inferior olivary nucleus and between inhibitory interneurons of the neocortex, hippocampus, and thalamus. All these synapses require the gap junction protein connexin36 (Cx36) for robust electrical coupling. Cx36 appears to interconnect neurons exclusively, and it is expressed widely along the mammalian neuraxis, implying that there are undiscovered electrical synapses throughout the central nervous system. Some central neurons may be electrically coupled by other connexin types or by pannexins, a newly described family of gap junction proteins. Electrical synapses are a ubiquitous yet underappreciated feature of neural circuits in the mammalian brain.

Cyclooxygenase (COX) is involved in modulating inflammatory response through the synthesis of prostaglandins. The inducible isoform of the enzyme, COX-2, is overexpressed in some malignant and premalignant lesions. Several preclinical and clinical studies have reported COX-2 inhibition as an effective strategy for chemoprevention. Nonsteroidal anitinflammatory drugs (NASIDs) such as celecoxib, are the most widely investigated COX-2 inhibitors. The oil-soluble diallyl sulfides (DAS) include monosulfides (DAMS), disulfides (DADS) and trisulfides (DATS). They were found to be effective against canine and human tumors, the mechanism of which remains unresolved. We attempted a comparative evaluation of the antiproliferative effect of DAS in HEK 293T cells. The cells were treated with increasing concentrations of DAMS, DADS and DATS. There were significant differences between the IC50 values of DAMS, DADS and DATS. RT-PCR was performed and the expression of COX-2 was compared with that of b actin. DATS inhibited COX-2 gene expression significantly stronger than DAMS and DADS. The data are suggestive of antineoplastic effect of DAS, mediated by controlling COX-2 expression.

Malignant tumors are extremely uncommon in infants, specifically in the head and neck region. We present a three-day-old infant with a large, polypoid, soft tissue mass arising from the floor of the mouth. Histologically, this neoplasm consisted of hypercellular and myxoid areas. A mixture of poorly oriented, small, undifferentiated, hyperchromatic, and round to elongate spindle cells was seen. A high degree of striated muscle differentiation was present, along with areas marked by a herringbone pattern, as well as hemangiopericytic vessels and rare mitosis. Immunohistochemical examinations revealed strong nuclear staining for myogenin and diffuse cytoplasmic staining for desmin and muscle-specific actin (HHF-35). The tumor did not stain for S-100. Based on histologic results and immunostains, this lesion was diagnosed as spindle cell rhabdomyosarcoma. This type of lesion involving the tongue is rarely seen in females, neither in association with a herringbone pattern nor with hemangiopericytic vessels. Furthermore, rare benign and malignant spindle lesions, such as cellular fibromatosis, fetal rhabdomyoma, infantile hemangiopericytoma, infantile rhabdomyofibrosarcoma, and infantile fibrosarcoma, should be in the differential diagnosis and excluded

INTRODUCTION: A retrospective review of 91 patients with brain metastases from malignant melanoma treated at New York University Medical Center between 1989-1999. Overall survival was the outcome evaluated. METHODS: Charts of 91 patients having malignant melanoma with brain metastases were reviewed. Cases were stratified according to therapy: surgical excision, surgical excision plus whole brain radiation therapy, gamma knife stereotactic radiosurgery, gamma knife stereotactic radiosurgery plus whole brain radiation therapy, and whole brain radiation therapy alone. Patients treated with gamma knife stereotactic radiosurgery plus radiation therapy were combined with patients treated with surgical excision plus radiation therapy and compared to those treated with radiation therapy alone. Prognostic characteristics of the two groups were compared and survival curves were generated using the Kaplan-Meier method. The Cox proportional hazards model was used to control for prognostic factors that differed between the groups. RESULTS: Patients treated with gamma knife stereotactic radiosurgery or surgical excision plus radiation therapy were younger, less likely to present with symptoms, and presented with fewer metastases to the brain than patients treated with radiation therapy alone. A survival benefit of 7.3 months (p = 0.05) was found to be associated with gamma knife radiosurgery or surgical excision plus radiation therapy over radiation therapy alone after controlling for differences in age, number of brain lesions, and presence of symptoms. DISCUSSION: This retrospective study of 91 patients treated for melanoma metastases to the brain attempts to examine the effectiveness of different treatments in prolonging survival. Our results suggest that surgical excision or stereotactic radiosurgery with gamma knife in addition to radiation therapy may be more effective than radiation alone at prolonging survival for patients with a limited number of brain lesions. CONCLUSION: Survival of patients with melanoma metastases to the brain may be prolonged by treatment with gamma knife stereotactic radiosurgery or surgical excision plus whole brain radiation therapy