Pediatric laryngeal carcinoma in a heterozygous carrier of Fanconi anemia

A case of invasive, keratinizing squamous cell carcinoma of the larynx in an 8-year-old female treated with laryngectomy is presented. Perinatal exposure to human papilloma virus and constitutional heterozygosity for a FANCC mutation were identified, though FANCC heterozygosity is not known to be cancer predisposing. An additional tumor-associated mutation in NOTCH1 was also identified potentially contributing to oncogenesis. This case illustrates an exceedingly rare type of cancer in the pediatric population and discusses diagnostic workup, evaluation of risk factors for head and neck cancer, and treatment options.

Identification of a Novel Allosteric Inhibitory Site on Tryptophan Hydroxylase 1 Enabling Unprecedented Selectivity Over all Related Hydroxylases

Pulmonary arterial hypertension (PAH) has demonstrated multi-serotonin receptor dependent pathologies, characterized by increased tone (5-HT_1B receptor) and complex lesions (SERT, 5-HT_1B, 5-HT_2B receptors) of the pulmonary vasculature together with right ventricular hypertrophy, ischemia and fibrosis (5-HT_2B receptor). Selective inhibitors of individual signaling elements – SERT, 5-HT_2A, 5HT_2B, and combined 5-HT2_A/B receptors, have all been tested clinically and failed. Thus, inhibition of tryptophan hydroxylase 1 (TPH1), the rate limiting step in 5-HT synthesis, has been suggested as a more broad, and thereby more effective, mode of 5-HT inhibition. However, selectivity over non-pathogenic enzyme family members, TPH2, phenylalanine hydroxylase, and tyrosine hydroxylase has hampered therapeutic development. Here we describe the site/sequence, biochemical, and biophysical characterization of a novel allosteric site on TPH1 through which selectivity over TPH2 and related aromatic amino acid hydroxylases is achieved. We demonstrate the mechanism of action by which novel compounds selectively inhibit TPH1 using surface plasma resonance and enzyme competition assays with both tryptophan ligand and BH4 co-factor. We demonstrate 15-fold greater potency within a human carcinoid cell line versus the most potent known TPH1/2 non-specific inhibitor. Lastly, we detail a novel canine in vivo system utilized to determine effective biologic inhibition of newly synthesized 5-HT. These findings are the first to demonstrate TPH1-selective inhibition and may pave the way to a truly effective means to reduce pathologic 5-HT and thereby treat complex remodeling diseases such as PAH.

Adenovirus type 8 keratoconjunctivitis--an outbreak and its treatment with topical human fibroblast interferon

An outbreak of keratoconjunctivitis is described which involved at least 186 people; adenovirus type 8 was identified in 50 of the cases. Topical human fibroblast interferon was assessed in a double-blind, placebo-controlled study in which 34 patients participated. Seventeen of the 34 trial patients yielded adenovirus type 8; three were infected with adenovirus type 7. The outbreak was curtailed by control of infection measures: principally careful hand-washing by medical personnel between cases and by discouraging attendance of new cases at the Eye Infirmary. Consequently the trial numbers are small. In addition there was a wide interpatient variation in the severity of infection. Therefore it was not possible to make any statistically valid conclusions concerning the recovery rate of patients receiving interferon or placebo.