18F-fallypride binding potential in patients with schizophrenia compared to healthy controls.

BACKGROUND: Molecular imaging of dopaminergic parameters has contributed to the dopamine hypothesis of schizophrenia, expanding our understanding of pathophysiology, clinical phenomenology and treatment. Our aim in this study was to compare (18)F-fallypride binding potential BP(ND) in a group of patients with schizophrenia-spectrum illness vs. controls, with a particular focus on the cortex and thalamus. METHODS: We acquired (18)F-fallypride positron emission tomography images on 33 patients with schizophrenia spectrum disorder (28 with schizophrenia; 5 with schizoaffective disorder) and 18 normal controls. Twenty-four patients were absolutely neuroleptic naïve and nine were previously medicated, although only four had a lifetime neuroleptic exposure of greater than two weeks. Parametric images of (18)F-fallypride BP(ND) were calculated to compare binding across subjects. RESULTS: Decreased BP(ND) was observed in the medial dorsal nucleus of the thalamus, prefrontal cortex, lateral temporal lobe and primary auditory cortex. These findings were most marked in subjects who had never previously received medication. CONCLUSIONS: The regions with decreased BP(ND) tend to match brain regions previously reported to show alterations in metabolic activity and blood flow and areas associated with the symptoms of schizophrenia.

Electrical Fields in the Vicinity of Small Wounds in Notophthalmus viridescens Skin.

The transepithelial potential (TEP) across the skin of Notophthalmus viridescens hindlimb digits was measured in animals immersed in artificial pond water (APW) that was 1.5 mM in NaCl, 0.06 mM in KCl, and 0.1 mM in CaCl2, before and after making a wound in the digit tip. Before wounding, the TEP of the digit skin averaged 35.3 mV ± 5.5 mV (S.E.M.), inside positive. After wounding, the TEP at locations distant from the wound approximated the TEP before wounding, but, at points progressively closer to the wound surface, the measured TEP was progressively less. The slope of this change in TEP, the lateral wound potential, averaged 41.7 mV/mm ± 9.5 mV/mm, with the regions closer to the wound being more negative than those away from the wound. When the Na+ channels of the outer surface of the external epidermal cells were blocked with benzamil (30 µM in APW), the TEP of the unwounded skin was reversed, to an average of - 14.1 mV ± 3.7 mV (inside negative). After benzamil-blocked digits were wounded, the lateral wound potentials averaged -21.5 mV/mm ± 4.0 mV/mm, with the polarity reversed: regions close to the wound were more positive than those away from the wound. The magnitudes of both the normal and the reversed wound fields are greater than those known to promote the migration of cells in vitro. What remains to be determined is how Notophthalmus viridescens epidermal cells and fibroblasts behave in such fields, and how this behavior relates to the process of wound healing under normal and modulated wound field conditions.