Male F1-mice (C3H/He X C57B1/6J) were exposed to styrene by inhalation (150 and 300 ppm; 6 h per day; 5 days) or intraperitoneally (175, 350 and 700 mg/kg per day, 5 days). No statistically significant increase was detected in the frequency of abnormal sperm heads 3 weeks (spermatids exposed) or 5 weeks (late spermatogonia/early spermatocytes exposed) after the beginning of the exposures.

Animals↗

PubMedDate not supplied

Co-occurrence of body dysmorphic disorder and Tourette's disorder. Three patient examples.

Explore the source record for details and available documents.

Adolescent↗

PubMedDate not supplied

Spectrofluorimetric methods for the measurement of the so called "microviscosity" of lipidic structures.

The cellular interactions involving the membrane depend on its physico-chemical nature and on the topographical distribution of the membrane receptors. At present, the role of the lipidic regions is not well defined; however, it is known than the fluidity or "microviscosity" of the lipidic components controls important processes in cellular biology. Different spectrofluorimetric methods, continuous or time resolved, susceptible to the cohesion of lipidic regions have been developed: 1. The anisotropy of fluorescence where the rotation of probes is studied (linked to the coefficient of diffusional rotation). 2. The inhibition of fluorescence where the kinetics of the reaction is practically diffusion controlled. 3. The formation of emissive intramolecular complexes where the internal rotations of interchromophoric bonds are studied. After the development of kinetic models, the methods have been tested with synthetic and natural organized assemblies. The values of "microviscosity" obtained with these methods may be different because the environments of probes are different. Therefore, the concept of "microviscosity", applied to biological membranes is limited.

Chemical Phenomena↗

PubMedDate not supplied

Membrane labelling by fluorescent probes: incorporation of TMA-DPH in erythrocyte membranes.

A study of the labelling of isolated resealed erythrocyte membranes by TMA-DPH has been carried out. A quantitative study shows that saturation appears to take place when increasing the relative quantity of probe bulk concentration to membrane concentration; this is readily interpreted by a simple incorporation model with a limited number of sites in the membrane. A qualitative study shows that an increase in the labelling leads to an evolution of the probe fluorescence properties; the existence of different types of sites is involved in the interpretation but the system is too complex to allow it to be represented by a simple model. As a consequence of this study, care has to be taken in labelling biological material so as to avoid excessive probe incorporation.

Diphenylhexatriene↗

PubMedDate not supplied

[Genetic control of the H-2 region of the cell surface: cationic amino groups in the periphery of T lymphocytes].

Spleen lymphocytes and erythrocytes from congenic mice of diffrent haplotypes were characterized on a precise biophysical basis (the anodic electrophoretic mobility, EPM) to correlate any subtle differences in the cell surface topochemistry with the H-2 specificity. Spleen T lymphocytes from A.CA (H-2f) and A.SW (H-2s) mice exhibited high values EPM, which were significantly different. In contrast, significant differences in the EPM of B cells and erythrocytes were not observed. Cell electrophoresis of spleen T lymphocytes (without " contaminating " B cells), before and after the chemical modification of the cell surface by treatment with small/non-toxic concentrations of maleic anhydride, showed the number of lysine side chain amino-groups in the periphery of cells with H-2f specificity to be about twice those on cells with H-2s haplotype. Such a difference was observed both in the case of premature T lymphocytes and mature T lymphocytes. The difference in the number of cationogenic amino-groups in the cell periphery contributing a positive charge, would explain the oberved difference in the EPM of H-2f and H-2s spleen T lymphocytes, and suggest that the macromolecules coded by the H-2 genes or other genes under H-2 control lead to delicate differences in the chemical composition of the surface membranes of cells of the two H-2 haplotypes, expressed only on high EPM lymphocytes of spleen (T or T-like cells).

Animals↗