The effect of substrate bulk stiffness on focal and fibrillar adhesion formation in human abdominal aortic endothelial cells.

Endothelial cell (EC) dysfunction contributes to atherosclerosis, which is associated with arterial stiffening and fibronectin (FN) deposition, by ECs and smooth muscle cells (SMCs). The effect of stiffness on the EC/FN interaction and fibrillar adhesion formation has been poorly studied. An in vitro model was prepared that included FN-coated polydimethylsiloxane (PDMS) films with similar hydrophobicity and roughness but distinct Young's modulus values, mimicking healthy (1.0 MPa) and atherosclerotic (2.8 MPa) arteries. Human aortic abdominal endothelial cells (HAAECs) seeded on 1.0 MPa PDMS films spread over time and reached their maximum surface area faster than on 2.8 MPa PDMS films. In addition, HAAECs appeared to organize focal adhesion more rapidly on 1.0 MPa PDMS films, despite the similar cell binding domain accessibility to adsorbed FN. Interestingly, we also observed up to a ~5-fold increase in the percentage of HAAECs that had a well-developed fibrillar adhesion on 1.0 MPa compared to 2.8 MPa PDMS films as verified by integrin α5 subunits, tensin, and FN staining. This variation did not affect EC migration. These results suggest that there are favourable conditions for FN matrix assembly by ECs in early atherosclerosis rather than at advanced stages. Our in vitro model will therefore be helpful to understand the influence of bulk stiffness on cells involved in atherosclerosis.

The MAN antigens are non-lamin constituents of the nuclear lamina in vertebrate cells.

The characterization of the human antiserum designated MAN has led to the identification of a subset of non-lamin proteins that are exclusively located at the nuclear periphery in all vertebrate cell types examined, from human to fish. Immunoreactive protein species were shown to comprise three major polypeptides of Mr 78000, 58000 and 40000. These antigens co-partitioned with the nuclear lamina during in situ isolation of nuclear matrices from lamin A/C-positive and -negative mammalian cells. Using double immunofluorescence, the spatial relationship of MAN antigens to type-A and type-B lamins was further examined throughout the cell cycle of lamin A/C-positive mammalian cells. In interphase HeLa and 3T3 cells, MAN antigens colocalized with both types of lamins at the periphery of the nucleus, but were absent from intranuclear foci of lamin B. As HeLa cells proceeded into mitosis, MAN antigens were seen to segregate from lamins A/C and coredistribute with lamin B. Lamins A/C disassembled during late prophase/early prometaphase and reassociated with chromatin in telophase/cytokinesis. In contrast, MAN antigens and lamin B dispersed late during prometaphase and reassembled on chromosomes in anaphase. Altogether, our data suggest that MAN antigens may play key functions in the maintenance of the structural integrity of the nuclear compartment in vertebrate cells.

Ultraviolet exposure to children from sunlight: a study using personal dosimetry.

Childhood exposure to ultraviolet (UV) radiation in sunlight may be an important risk factor for later development of skin diseases. We quantified the UVB radiant exposure on the wrist and face of children performing mixed outdoor activities at a summer camp. Polysulfone film badges were attached directly to the skin for several hours and simultaneously were used to measure ambient UVB levels. The results for the ratio of site-specific exposure to ambient exposure indicate a high degree of intersubject variability, a parity of samples taken in right and left positions, and a significantly higher exposure on the wrist compared with the face. The technique was well accepted by the subjects but some badges could not be read because of loss or damage. Measurement of exposure ratios in additional settings as well as data on childhood activity patterns are needed for an overall assessment of childhood exposure.

[Singh femoral index in vertebral osteoporosis]. / L'indice fémoral de Singh dans l'ostéoporose vertébrale.

In 48 patients with osteoporosis and at least one vertebral fracture, the Singh vertebral index, which assesses the femoral trabeculation, was compared to the Meunier vertebral radiologic index, which is determined according to the number and severity of vertebral deformations. The femoral index was abnormal in all patients. However, the threshold level, set by Singh at Stage IV, which supposedly discriminates between subjects with and without osteoporosis could not be confirmed as one-third of the patients with at least one vertebral fracture were Stage V. A statistically significant correlation was found between the femoral index and the vertebral radiological index.

Comparative force-velocity relation and analyses of myosin of dog atria and ventricles.

The isolated muscle and purified myofibrillar proteins of canine atria and ventricles were compared relative to force-velocity relations and rate of adenosine 5'-triphosphatase (ATPase) activity as a function of calcium concentrations. The maximal stress development of isolated trabeculae of canine atria was similar to that of canine right ventricular papillary muscles when analyzed at saturating calcium concentrations (7.5 mM); however, stress was less in the atria when studied at normal calcium concentrations (2.5 mM). The maximal velocity of shortening of atrial trabeculae was about 2.3 times higher than that of ventricular muscle. Regulated actomyosin characterized from the myofibrillar proteins of the two tissues gave directionally similar calcium sensitivity. The maximum velocity of shortening for actin-activated atrial myosin of the dog was approximately 1.8 times higher when the latter was analyzed as a function of actin concentration. Both maximal tension of isolated muscle and regulated actomyosin ATPase activity were dependent on calcium concentration.

Comparative evaluation of carprofen and indomethacin in rheumatoid patients.

Thirty-six patients with definite or classical rheumatoid arthritis were studied in a 6-week double-blind parallel trial. They were randomly divided into three groups and received either carprofen stepwise 150, 200, and 250 mg/day, carprofen 350, 400, and 450 mg/day or indomethacin 100 mg/day. Classical methods and parameters for evaluating the disease activity of rheumatoid arthritis were used. A large panel of laboratory tests were also involved in the assessment of toxicity. Although the incidence of adverse effects was similar for both drugs, cutaneous and gastrointestinal symptoms were more frequent with carprofen than with indomethacin, whereas central nervous system reactions were elicited more often with the latter drugs. For most of the efficacy variables studied, the carprofen high dosage regimen at weeks 5 and 6 was shown statistically superior or at least not different from the indomethacin group; both of these were superior to the carprofen low dosage regimen.