Neurobiology of social behavior abnormalities in autism and Williams syndrome

Social behavior is a basic behavior mediated by multiple brain regions and neural circuits, and is crucial for the survival and development of animals and humans. Two neuropsychiatric disorders that have prominent social behavior abnormalities are autism spectrum disorders (ASD), which is characterized mainly by hyposociability, and Williams syndrome (WS), whose subjects exhibit hypersociability. Here we review the unique properties of social behavior in ASD and WS, and discuss the major theories in social behavior in the context of these disorders. We conclude with a discussion of the research questions needing further exploration to enhance our understanding of social behavior abnormalities

Polyamine biosynthesis inhibitors combined with systemic hyperthermia in cancer therapy.

A Phase I clinical trial has been initiated at the University of Arizona Cancer Center which combines escalating oral doses of the polyamine biosynthesis inhibitor alpha-difluoromethylornithine (DFMO), with systemic hyperthermia (approximately 41.5 degrees C) in the treatment of metastatic melanoma. The rationale for the combination of hyperthermia and polyamine biosynthesis inhibitors in the treatment of human cancers includes studies which show that depletion of endogenous polyamines, as a result of treatment with DFMO, sensitizes both rodent and human tumor cells to the cytotoxic effects of hyperthermia. Heat shock induces the first enzyme in polyamine catabolism, spermidine/spermine N1-acetyltransferase (N1-SAT). The consequently acetylated forms of spermidine and spermine are then constitutively oxidized by the enzyme polyamine oxidase (PAO). Both CHO and human A549 lung cancer cells exhibit heat-inducible polyamine acetylation, display potent heat sensitization after polyamine depletion, and ultimately reveal prolonged expression of thermotolerance. Conversely, HeLa cells do not demonstrate heat-inducible polyamine catabolism, are not sensitized to heat with DFMO, and display more rapid kinetics of thermotolerance decay. These laboratory studies suggest that enhancement of the cytotoxic action of hyperthermia by DFMO occurs as a consequence of the inhibition of polyamine catabolism, a heat-inducible process that affords some form of protection to cells undergoing heat stress. Human melanoma cultures demonstrate heat-inducible polyamine catabolism and are sensitized to hyperthermic cytotoxicity by DFMO. To date, 24 systemic hyperthermia treatments have been delivered to nine patients with metastatic melanoma in conjunction with oral DFMO under this Phase I clinical trial

Mutant small heat-shock protein 27 causes axonal Charcot-Marie-Tooth disease and distal hereditary motor neuropathy

Charcot-Marie-Tooth disease (CMT) is the most common inherited neuromuscular disease and is characterized by considerable clinical and genetic heterogeneity. We previously reported a Russian family with autosomal dominant axonal CMT and assigned the locus underlying the disease (CMT2F; OMIM 606595) to chromosome 7q11-q21 (ref. 2). Here we report a missense mutation in the gene encoding 27-kDa small heat-shock protein B1 (HSPB1, also called HSP27) that segregates in the family with CMT2F. Screening for mutations in HSPB1 in 301 individuals with CMT and 115 individuals with distal hereditary motor neuropathies (distal HMNs) confirmed the previously observed mutation and identified four additional missense mutations. We observed the additional HSPB1 mutations in four families with distal HMN and in one individual with CMT neuropathy. Four mutations are located in the Hsp20-alpha-crystallin domain, and one mutation is in the C-terminal part of the HSP27 protein. Neuronal cells transfected with mutated HSPB1 were less viable than cells expressing the wild-type protein. Cotransfection of neurofilament light chain (NEFL) and mutant HSPB1 resulted in altered neurofilament assembly in cells devoid of cytoplasmic intermediate filaments