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L Malaval

Publications and source records attributed to L Malaval.

42 records · Page 3Linked to original sources
PubMed1984

Serum bone Gla-protein: a specific marker for bone formation in postmenopausal osteoporosis.

Mean (+/- SD) serum bone Gla-protein (BGP or osteocalcin) was normal (7.0 +/- 3.3 ng/ml) in 26 patients with untreated postmenopausal osteoporosis ( PMO ). But 9 patients had values either above (4) or below (5) the normal values obtained in 35 age-matched control women (6.9 +/- 1.25 ng/ml). Serum BGP correlated positively with relative osteoid volume, relative osteoid surfaces, tetracycline labelled surfaces, and bone formation rate but not with resorption surfaces. Based on normal values for osteoid volume, patients were classified as having high (HF, 9 patients), normal (NF, 12 patients) and low osteoid formation (LF, 5 patients). Serum BGP (+/- SEM) was significantly lower in LF group (2.7 +/- 0.9 ng/ml) and significantly higher in HF group (9.7 +/- 0.8 ng/ml) than in the NF group (7.0 +/- 0.6 ng/ml). Serum alkaline phosphatase and urinary hydroxyproline did not discriminate between these three groups and did not correlate significantly with any of the measured histomorphometric indices in biopsy specimens in these patients. Serum BGP appears to be a specific marker for bone formation and can predict the histological profile in PMO . Serum BGP might be useful in investigating patients with PMO and should be valuable in assessing the effects of treatments that increase bone formation.

Aged↗
PubMed1984

[Comparative study of serum osteocalcin and of the histomorphometric evaluation of iliac biopsy in postmenopausal osteoporosis].

The histological examination of iliac biopsies in patients with osteoporosis shows varying stages of remodeling which cannot be detected by the usual laboratory tests. We measured the serum osteocalcin level, a new test, specific for bone, in 26 postmenopausal women with primary osteoporosis. The results were correlated to the findings of the iliac biopsy. Osteocalcin is significantly related to all the parameters of bone formation but not with bone resorption. When patients were divided into 3 groups, depending on the stage of remodeling from the biopsy, osteocalcin was significantly increased in the group with a high level of bone formation, and lowest in the group with decreased osteoblastic activity than in the group with normal remodeling. Neither the serum alkaline phosphatase nor the measurement of urinary hydroxyproline could distinguish between these group.

Aged↗
PubMed1982

Isolation of functional giant smooth muscle cells from an invertebrate: structural features of relaxed and contracted fibers.

The giant smooth muscle fibers of a ctenophore were isolated by enzymatic digestion. These fibers are multinucleated cells, up to 50 micrometers in diameter and 2 cm in length. Their ultrastructure and membrane electrical properties are similar to those of in situ fibers. Relaxed, coiled (partially contracted), and fully shortened states were distinguished in isolated cells and studied by scanning and transmission electron microscopy. Calcium-containing mitochondrial granules were found in the coiled cells but not in either the relaxed or the fully shortened cells. The relaxed cell is characterized in cross section by the density of myosin filaments (457 +/- 15 per micrometer2) and the thin-to-thick filament ratio (5.2 +/- 0.2). In the coiled cell, the muscle lattice does not expand uniformly, as shown by the variability of myosin spacing, and the thin-to-thick filament ratio decreases. Both clockwise and counterclockwise coiling occur along the same fiber. The implications of these findings with respect to the structure of the contractile apparatus are discussed.

Actins↗
PubMed1982

Electron microscopy and x-ray microanalysis of calcium-binding sites of the plasma membrane of Beroe giant smooth muscle fibre.

When they are fixed with glutaraldehyde in the presence of calcium ions, the plasma membranes of Beroe giant smooth muscle fibres display micropapillae filled with an electron-dense deposit. After freeze-fracturing of fixed tissue, the micropapillae are still present, therefore their shape and size are determined during or before glutaraldehyde fixation, and are not due to rearrangement during subsequent steps of tissue processing; intramembranous particles are seen at the periphery rather than at the top of micropapillae. In conventional stained sections, the surface of most micropapillae is surrounded by fine fibrils; when the fuzzy coat is separated from the muscle cell by a clear space, this fibrillar material becomes conspicuous and links the micropapillae to the coat. After calcium-free (EGTA) fixation, the plasma membrane is completely free of electron-dense sites but "empty' micropapillae can be seen. X-ray microanalysis of single electron-dense deposits by wavelength-dispersive spectrometry reveals a high calcium content. A weak osmiophily is suspected, but does not seem to interfere with this analysis of calcium. The highest peak-to-background ratios for calcium were obtained using the smallest aperture of the Wehnelt of the analytical microscope. In the Discussion, the micropapillae are compared to similar structures described by other authors in a variety of cell types.

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