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Biomedical subjects

D Gaillard

Publications and source records attributed to D Gaillard.

At least 109 records · Page 6Linked to original sources
PubMed1988

[Subperiosteal chondroma. Diagnostic contribution of x-ray computed tomography. Apropos of 2 cases].

Results of CT scan exploration are reported in two cases of subperiosteal chondroma, one in a 4 year old child affecting the anterior tibial tuberosity the other in a 9 year old child involving the upper end of humerus. Data from CT scan imaging were undoubtedly superior to those of conventional radiography and appear to be characteristic of this benign cartilaginous tumor, greatly facilitating correlation between clinical, radiological and pathologic findings. The scanner should allow certain situations to be dedramatized and the surgical attitude adapted when the functional prognosis is involved.

Bone Neoplasms↗
PubMed1987

Growth-promoting activity in serum-free medium of kallikreinlike arginylesteropeptidases from rat submaxillary gland.

The characterization and purification of the growth-promoting activity present in rat submaxillary gland extracts, known to be required for the proliferation of adipose precursor cells in serum-free medium, have been undertaken. Fractionation of the extracts by ion-exchange chromatography, gel filtration, and affinity chromatography on immobilized benzamidine allowed the copurification of the mitogenic activity with two distinct arginylesteropeptidases of apparent molecular weight 25,000; one of these enzymes has been purified to homogeneity and shown to be immunologically related to tonin, a well-characterized kallikreinlike protease from submaxillary gland. The specificity of both enzymes was similar to that of plasma and glandular kallikreins, as indicated by the relative rates of hydrolysis of peptide p-nitroanilide substrates. Prior treatment of the kallikreinlike proteases with phenylmethylsulfonylfluoride or aprotinin abolished completely both mitogenic and arginylesteropeptidase activities, indicating that enzymatic activity was essential for the manifestation of their growth-promoting ability. The kallikreinlike proteases from rat submaxillary gland were able to replace thrombin to support the proliferation of Chinese hamster lung fibroblasts in serum-free medium. These results underline the role of proteases in controlling cell growth and are discussed in light of adipose tissue development.

Animals↗
PubMed1987

[Value of a meiotic study of male sterility].

Both in men where the somatic karyotype is abnormal as well as in cases where it is normal, it is worth while studying meiosis in the male. The picture of meiosis has been studied in the main from testicular biopsies and also partly from spermatic line cells found in sperm. Studying the haploid portion of the male pronucleus using the hamster test reflects the process of meiosis. In this way it has been possible to individualise different pathological entities such as asynapsis or desynapsis, alterations in synaptic complexes, the presence of several nucleoli or micronucleoli in the pachytene stage, hyper or hypo polidies, the presence of univalents and the breakdown of bivalents, oligochiasmatasis, chain or ring pictures or early desynapsis of the sexual vesicle in the diacinesis and in the first metaphase stage. Aneuploidies have been found in the second metaphase stage or when carrying out chromosome analysis on the male pronucleus. The abnormalities in the number of chromosomes which are found with the formula 47,XXY, may be due to faults in spermatogenesis, but in the case of the double Y in 47,XYY the extra Y will rarely be found during meiotic divisions. The Robertsonian translocations causing abnormalities in structure are due to the formation of trivalents whereas reciprocal translocations give rise to the idea of quadrivalent pictures mainly associated with faults in spermatogenesis. Finally, autosomal chromosome translocations seem to have more severe meiotic repercussions, particularly in cases where the inactive autosomal X chromosome is involved. Even where a somatic karyotype is normal in a fertile subject that does not mean that there is no meiotic abnormality present, because 8-10% of the cells that were studied showed such an abnormality.

Chromosome Aberrations↗
PubMed1986

Telangiectatic osteosarcoma.

Two cases of telangiectatic osteosarcoma are described. The difficulty in differentiating this tumour from aneurysmal bone cyst is emphasized both from the pathological and radiological aspects.

Adolescent↗
PubMed1986

[Familial esophageal leiomyomatosis associated with Alport's syndrome in a 9-year-old boy].

The authors describe a family in which the mother and one son are affected by oesophageal leiomyomatosis and nephritis with haematuria. The mother also presents hypertrophy of vulva and clitoris, and her son has perceptive deafness and congenital cataract. In the medical literature only 15 cases of oesophageal leiomyomatosis in children and adolescents could be found. The association with Alport's syndrome was first described by Torres and Guarner in 1983.

Adult↗
PubMed1985

Fetuin modulates growth and differentiation of Ob17 preadipose cells in serum-free hormone-supplemented medium.

A serum-free hormone-supplemented medium able to support the growth of rodent adipose precursor cells has been used to characterize additional components from serum required for the differentiation of preadipose Ob17 cells into adipose-like cells. Fetuin is shown to behave as a growth-promoting agent for these cells. In addition to growth hormone, triiodothyronine and a low-molecular weight component(s) also purified from serum, fetuin is required for the full expression of the differentiation program. Other serum proteins as well as other mitogenic factors are unable to substitute for fetuin. A possible role of fetuin in the development of adipose tissue is discussed.

Adipose Tissue↗
PubMed1985

Characterization of ouabain-resistant mutants of the preadipocyte Ob17 clonal line. Adipose conversion in vitro and in vivo.

After exposure to a mutagenic drug (ethylmethanesulfonate), mutant clones of Ob17 preadipose cells resistant to the cytotoxic action of ouabain have been isolated. Their ability to grow in serum-supplemented medium containing greater than or equal to 3 mM ouabain is consistent with the decreased ouabain sensitivity of K+ transport observed in one of these clones (Ob17-OR11). Ouabain-resistant mutants retain their ability to convert into adipose-like cells in vitro with a frequency similar to that of original Ob17 cells. Long-term maintenance of Ob17-OR11 cells in ouabain-enriched medium leads to a higher frequency of adipose conversion, which is linked to a rather specific and limited growth-promoting effect of the drug. Undifferentiated Ob17-OR11 cells, when injected subcutaneously into athymic mouse, give rise in vivo to a fat pad containing ouabain-resistant mature adipocytes. Therefore, Ob17-OR11 clone should be a useful tool to distinguish in vivo between intrinsic and extrinsic factors involved in the differentiation of adipose precursor cells.

Adipose Tissue↗
PubMed1985

Small, asymptomatic angiomyolipomas of the kidney.

Ultrasound (US) detected 27 small, asymptomatic renal angiomyolipomas in 18 patients. Twenty-five lesions were diffusely hyperechoic and 2 were heterogeneous. Nephrotomography was positive in 8 out of 12 patients (67%), CT in 12/14 (86%), and angiography in 10/14 (71%). Percutaneous fine-needle biopsy confirmed the diagnosis in 8 out of 12 patients (67%). Nephrotomography and angiography were nonspecific, whereas CT and biopsy were most specific because of the presence of fatty tissue. Angiography helped clarify the degree of vascularity of the masses. If the diagnosis can be made preoperatively, more conservative management can be undertaken.

Adolescent↗
PubMed1985

[Lipoprotein lipase and adipocyte differentiation].

Some hormonal factors, possibly involved in the proliferation and differentiation of adipose precursor cells in vivo, have been characterized in vitro using different preadipocyte cell lines established from rodent adipose tissue. The process of adipose conversion has also been studied using these cell lines; in this process, stem cells (adipoblasts) were committed at any cell division during the growth phase. At confluence, committed cells (preadipocytes) underwent a limited number of mitoses and differentiated into adipose cells, whereas the uncommitted cells remained as stem cells in the cell population. This stochastic model could be extended to the development of rat adipose tissue in vivo. The study of adipose conversion showed the early emergence of lipoprotein lipase (LPL) and monoglyceride lipase (MGL). LPL activity appeared in the cells before any triglyceride accumulation. In contrast, this accumulation seemed dependent upon the emergence of glycerol-3-phosphate dehydrogenase. In vitro experiments clearly established that LPL-containing (differentiating) cells underwent postconfluent mitoses. This limited proliferation was in agreement with previous data obtained in vivo and indicates that only triglyceride-containing (mature) cells could not divide.

Adipose Tissue↗
PubMed1985

Adipose conversion of ob17 cells and hormone-related events.

The ob17 preadipocyte clonal line has been established from the adipocyte fraction of the epididymal fat pads of adult C57 BL/6J ob/ob mice. In vivo, injection of ouabain-resistant mutant cells (ob 17OR11 cell line) into athymic mice is followed by the formation of fat pads containing ouabain-resistant mature fat cells. In vitro, ob17 cells develop after confluence biochemical and morphological characteristics of adipocytes. The adipose conversion process is best represented by a stochastic model in which a pool of stem cells (adipoblasts) give rise to clusters of adipose cells and to additional stem cells that remain in the population. The role of the different factors involved in such conversion is discussed; (1) factors that enhance the number of susceptible cells (ACF or ACF-like compounds), (2) factors without which no adipose conversion takes place (triiodothyronine, growth hormone and other factors still to be characterized), (3) factors that enhance the expression of the differentiation program (insulin). The early emergence of lipoprotein lipase occurs normally in insulin-depleted medium. The separation of ob17 cells by isopycnic centrifugation shows that lipoprotein lipase is present at high levels in early differentiating cells which are still devoid of late markers, ie glycerol-3-phosphate dehydrogenase and triglycerides. These results are discussed with respect to the determination of cellularity during development of adipose tissue in vivo.

Adipose Tissue↗
PubMed1985

[Laurence-Moon-Bardet-Biedl syndrome, chronic diffuse tubulo-interstitial nephritis and liver involvement].

The authors report the case of a 6-year-old girl with Laurence-Moon-Bardet-Biedl syndrome and chronic tubulo-interstitial nephritis with glomerulosclerosis requiring chronic peritoneal dialysis, then haemodialysis. One year later, minimal hepatic involvement occurs, leading to portal hypertension. The liver biopsy reveals periportal fibrosis with many small bile ducts.

Bile Ducts, Intrahepatic↗