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Biomedical subjects

L Lévy

Publications and source records attributed to L Lévy.

16 recordsLinked to original sources
PubMed2005

[Presentation of the French translation of the Breast Imaging Reporting System and Data System (BI-RADS)].

BI-RADS is a system of assistance to the drafting of the reports more and more used in the world and soon directly implemented on mammography and ultrasound units. The categories of evaluation of the BI-RADS allow a clear synthesis of the descriptive data resulting from the use of the lexicon and invite the radiologist to a reasoned, objective and less intuitive step. They give an action to be taken and responsibility to the radiologist and the referring physicians in the assumption of the patients. The 4th edition of the BI-RADS mammography appeared in 2003, and is now associated with the first editions of the BI-RADS ultrasound and MRI.

Breast Diseases↗
PubMed2004

[Mammographic stable lesions and carcinomas].

Stable breast carcinomas at mammography are infrequent and typically correspond to low-grade non-invasive neoplasms. Diagnosis may be delayed by several months to a few years. This time delay to diagnosis may be reduced by using optimal mammographic technique and careful image interpretation. These lesions frequently are misclassified as BIRADS class III lesions. Comparison with prior mammograms is mandatory for accurate diagnosis of these lesions.

Breast Neoplasms↗
PubMed2002

[Digital mammography and computer assisted diagnosis].

Until recently, the film has remained the only medium of information in mammography. The film is used to record, to exploit, to store and to transmit the image. Computerization of images allows to dissociate and to optimize these different functions. Among classical factors of image quality (spatial resolution, contrast, noise), new factors should be added like the detective quantum efficiency and the conversion factor. Radioluminescent screens, then digital sensors for breast stereotactic imaging have been marketed. Manufacturers are now testing full field digital mammographs. Digital imaging allows many applications (computed-aided diagnostic, 3D imaging.) and permits the easy transfer of images for diagnosis and teaching. Three parts are presented in this chapter. The first one describes the different imaging modalities and gives a reminder of the different elements related to image quality. The second one is related to the practical aspects of full field mammography, the reading of mammograms on a review station, ergonomy in full field mammography and to possible changes for screening mammography. The third part is devoted to computed aided diagnosis and its possible application in screening.

Diagnosis, Computer-Assisted↗
PubMed1997

Somatostatin and growth hormone-releasing hormone in normal and tumoral human breast tissue: endogenous content, in vitro pulsatile release, and regulation.

Endogenous production of SRIH and GHRH was analyzed in human breast tissue. SRIH precursor (pro-SRIH) was identified after Sephadex G-50 filtration of acetic acid extracts of normal and tumoral human breast samples. SRIH-(1-14) or -(1-28) could not be detected in breast tissue, whereas the immunoreactive SRIH released in vitro was characterized as SRIH-(1-28). Endogenous production of GHRH was assessed by identification of GHRH messenger ribonucleic acid by PCR followed by sequencing of the amplified complementary DNA and by high performance liquid chromatographic characterization of immunoreactive GHRH contained in the tissue and released in vitro. There were no differences in pro-SRIH or GHRH-(1-44) tissue contents between normal and tumoral samples. The release of both peptides was evidenced in perifusion and static incubation. Perifusion of normal breast tissue (n = 3) showed pulsatile release of SRIH and GHRH. Perifusion of tumors (n = 4) showed SRIH release in 50% of the cases. SRIH release was pulsatile in one case. GHRH release was observed in the four tumoral samples analyzed, but was pulsatile in only one case. In static incubation, tumors (n = 6) secreted 13 times more GHRH than did normal samples (n = 3; 383 +/- 92 vs. 29.6 +/- 4.6 fmol/mg protein; P < 0.05). Stimulation of GHRH release by exogenous SRIH was observed only with the normal tissue. Together these data provide evidence for the existence of local production of SRIH and GHRH by human breast. Hypersecretion of GHRH by breast tumors indicates that this peptide could play a role in maintaining epithelial cell proliferation as is the case for other peptides produced locally.

Breast↗
PubMed1994

Ca(2+)-dependent protein kinase C isoforms in rat pituitary hyperplasia: effect of in vivo treatment with quinagolide.

Ca(2+)-dependent protein kinase C (PKC) activity, diacylglycerol levels and PKC alpha, beta I, beta II and gamma expression were analyzed in the pituitary of female rats treated with estradiol alone (2 months) or in combination with quinagolide in the second month. Polymerase chain reaction (PCR) and Western blot analysis revealed the presence of PKC alpha, beta I and beta II isoenzymes in the rat pituitary gland but not of PKC gamma isoenzymes. Increases in pituitary weight and plasma prolactin levels induced by estradiol were associated with an increase in diacylglycerol pituitary content (1.55 +/- 0.06 versus 1.12 +/- 0.17 nmol diacylglycerol/mg protein in controls, P < 0.01). Cotreatment with quinagolide reversed these effects. Changes in PKC activity were accompanied by parallel changes in PKC alpha and beta I expressions. Estradiol treatment increased the expression of these isoforms whereas cotreatment with quinagolide antagonized these effects. PKC beta II expression was not affected. In conclusion, Ca(2+)-dependent PKC activity and protein expression are increased in hyperplastic pituitary cells, suggesting the involvement of this class of PKCs in the rat pituitary cell proliferation and/or hormonal secretion. This is further assessed by the fact that the dopamine receptor agonist treatment decreases activity and expression of these PKCs in parallel with the decrease in hormonal secretion and cell proliferation.

Aminoquinolines↗
PubMed1993

Invasive human pituitary tumors express a point-mutated alpha-protein kinase-C.

Protein kinase-C (PKC) is a ubiquitous eukaryotic kinase that plays a key role in transmembrane signaling and influences important cellular processes, such as proliferation. Increases in its activity and expression have been demonstrated in adenomatous human pituitaries, with protein expression being the highest in invasive tumors (1). Moreover, in these same invasive tumors, the mean increase in expression (8.9-fold) does not correlate with the mean increase in activity (2.6-fold), suggesting a dysfunction in PKC in these tumors. Here, we show that the PKC alpha-isoform (alpha PKC) is overexpressed in human pituitary tumors. The complete sequencing of the PKC cDNA from four invasive tumors has revealed a point mutation that is absent in the noninvasive tumors analyzed. The point mutation is located at position 294 of the protein, in the V3 region, leading to a substitution of a negatively charged aspartic acid by an apolar glycine. Thus, not only is alpha PKC overexpressed in human pituitary tumors, but it is also structurally altered in the invasive subpopulation of these tumors.

Amino Acid Sequence↗
PubMed1991

[Thyroid cancer revealed by a suppressive hot nodule].

We report the case of a 62-year old woman in euthyroidism who presented with a thyroid cancer located within a hot nodule. The nodule was partially extinctive, and the triiodothyronine test showed incomplete suppression. Fine needle cytology showed no malignant cells. Systematic lobectomy was performed, and the diagnosis of cancer was made at pathology. This rare situation does not mean that all non-toxic hot nodules must be removed, but if surgery is decided an extemporaneous histological examination is mandatory. Besides, such cases provide an additional argument in favour of surgery or treatment of toxic adenomas.

Female↗