Serotonin antagonists do not attenuate activity-induced phase shifts of circadian rhythms in the Syrian hamster

A variety of observations from several rodent species suggest that a serotonin (5-HT) input to the suprachiasmatic nucleus (SCN) circadian pacemaker may play a role in resetting or entrainment of circadian rhythms by non-photic stimuli such as scheduled wheel running. If 5-HT activity within the SCN is necessary for activity-induced phase shifting, then it should be possible to block or attenuate these phase shifts by reducing 5-HT release or by blocking post-synaptic 5-HT receptors. Animals received one of four serotonergic drugs and were then locked in a novel wheel for 3 h during the mid-rest phase, when novelty-induced activity produces maximal phase advance shifts. Drugs tested at several doses were metergoline (5-HT_1/2 antagonist; i.p.), (+)-WAY100135 (5-HT_1A postsynaptic antagonist, which may also reduce 5-HT release by an agonist effect at 5-HT_1A raphe autoreceptors; i.p.), NAN-190 (5-HT_1A postsynaptic antagonist, which also reduces 5-HT release via an agonist effect at 5-HT_1A raphe autoreceptors; i.p.) and ritanserin (5-HT_2/7 antagonist; i.p. and i.c.v.). Mean and maximal phase shifts to running in novel wheels were not significantly affected by any drug at any dose. These results do not support a hypothesis that 5-HT release or activity at 5HT1, 2 and 7 receptors in the SCN is necessary for the production of activity-induced phase shifts in hamsters.     

Biophysical membrane correlates of tolerance and dependence on alcohol

A large number of studies have given clear indications that ethanol does affect the physicochemical properties of the membrane. Membrane reorganization and adaptation can develop against the acute disordering effect of ethanol during chronic intoxication. Nevertheless, there has been so far no direct evidence of correlations between functional tolerance or dependence and membrane physical states. Membrane physical state can be assessed by fluorescence polarization of DPH in the absence (measure of membrane 'fluidity') or presence (measured of membrane sensitivity) of ethanol added in vitro. Functional tolerance has been already correlated with a reduced synaptic membrane sensitivity to ethanol (membrane tolerance). Behavioural dependence was shown to be quantifiable by measurement of alcohol intake in a free choice situation (water/alcohol) solution). This dependence model allowed us to define a membrane dependence which consists in an increased membrane rigidity (or decrease in 'fluidity') persistent after withdrawal, and which was correlated to the intensity of the behavioural dependence. This biophysical expression of dependence seems rather independent of the biophysical membrane tolerance (resistance to the acute ethanol fluidizing effect), which was found to be rapidly reversible after withdrawal and re-induced by alcohol re-intake, requiring recent periods of current abuse to be expected.     

Chromosome aberrations in 500 couples referred for in-vitro fertilization or related fertility treatment

Cytogenetic studies were performed in 500 couples referred forin-vitro fertilization or gamete (zygote) intra-Fallopian transfer.Thirteen individuals (1.3%) with chromosomal abnormalities werefound. Four major types of anomalies were observed: reciprocaltranslocations (n = 3), inversions (n = 2), iso-Xq chromosomes(n = 2) and sex chromosome number mosaics (n = 4). Moreovertwo males with respectively a 47,XYY and a 47,XY, mar⁺ karyotypewere identified. These data pointed to a higher incidence ofchromosomal aberrations in this infertile population as comparedto a neonatal population without obvious chromosomal pathology.Analysis of the chromosomes which were involved in hyperdiploidyand hypodiploidy in the 30 000 metaphases evaluated, showeda high proportion of cells that had lost or gained an X-chromosome.A puzzling finding was the statistically significant low incidenceof 45,X metaphases (0.9) in women of couples treated on andrological indication as compared to the frequencyof 45,X chromosome complements in women with tubal disease (4.0) or of couples with an idiopathic (4.3) or mixed female and male (6.7) indication.     

Simultaneous expression of keratin and glial fibrillary acidic protein by the same cells in epiretinal membranes.

The identification of cells comprising epiretinal membranes is difficult because of the phenotypic changes that occur. Examination of intermediate filament protein content by immunocytochemical analysis can help to identify some cells with altered ultrastructure but is not always definitive because altered expression of intermediate filament proteins can also occur. To examine this issue further, the authors utilized a postembedding immunocytochemical technique with epiretinal membranes in which they were able to double label for keratin, a useful marker for identifying retinal pigment epithelial cells, and glial fibrillary acidic protein (GFAP), a useful marker for identifying glial cells. Nine of ten idiopathic epiretinal membranes contained cells that labeled for GFAP and not keratin. Two of these membranes also contained cells that labeled only for keratin and one membrane contained cells that simultaneously labeled for both GFAP and keratin. Other types of epiretinal membranes had an equal participation by cells that expressed only GFAP or keratin (12 of 17 membranes contained cells positive for keratin; 13 of 17 contained cells positive for GFAP). Ten of 17 nonidiopathic membranes contained cells simultaneously expressing GFAP and keratin, although they comprised only a minor subpopulation of the total number of cells present. These findings demonstrate that keratin and GFAP are not mutually exclusive intermediate filament proteins in cells of epiretinal membranes and that, although each may provide a helpful adjunct for cell type identification, neither is an absolutely specific marker.     

Verruciform xanthoma of the oral mucosa

The verruciform xanthoma is a rather rare lesion that is mostly confined to the oral mucosa. The clinical picture may vary considerably. The diagnosis is based on the presence of numerous xanthoma cells in the connective tissue papillae. A case of verruciform xanthoma in the floor of the mouth in a 45-year-old woman is presented. The findings reported in the literature are also discussed.