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Biomedical subjects

R Gilles

Publications and source records attributed to R Gilles.

At least 55 records · Page 3Linked to original sources
PubMed1994

Apocrine carcinoma: clinical and mammographic features.

PURPOSE: To describe the mammographic features of apocrine carcinoma and assess the patterns of calcifications associated with these lesions. MATERIALS AND METHODS: Clinical and mammographic features from 17 patients with apocrine carcinoma were retrospectively reviewed. Special attention was paid to the presence of mixed form, diffusely scattered microcalcifications on mammograms. RESULTS: Patients were referred for clinical (n = 10), mammographic (n = 2), or both clinical and mammographic (n = 5) abnormalities. Findings at clinical examination included a palpable breast mass (n = 12), multiple breast masses (n = 1), and bloody nipple discharge (n = 2); two patients had normal findings. Fourteen patients had opacities at mammography. These opacities were associated with microcalcifications in 10 cases. Three patients had microcalcifications without opacities; one of those three patients exhibited a mixed form of diffusely scattered calcifications. CONCLUSION: Clinical and mammographic features of apocrine carcinoma do not differ from those of invasive ductal carcinoma.

Adult↗
PubMed1994

Nonpalpable breast tumors: diagnosis with contrast-enhanced subtraction dynamic MR imaging.

PURPOSE: To determine the accuracy of contrast material-enhanced subtraction dynamic magnetic resonance (MR) imaging in the diagnosis of nonpalpable breast tumors. MATERIALS AND METHODS: One hundred forty-three patients underwent surgical biopsy of a nonpalpable breast lesion. Their mammograms showed microcalcifications (n = 80), opacity (n = 52), architectural distortion (n = 10), or asymmetric density (n = 1). All patients underwent a preoperative gadolinium tetraazacyclododecanetetraacetic acid-enhanced subtraction dynamic study. Any early contrast enhancement in the breast parenchyma was considered pathologic. RESULTS: At histologic analysis, 27 intraductal carcinomas, 37 invasive carcinomas, and 79 benign lesions were found. Dynamic MR studies showed early contrast enhancement in 61 of 64 breast cancers (sensitivity, 95%) and in 37 of 79 benign lesions (specificity, 53%). Two invasive lobular carcinomas and one tubular carcinoma showed no early contrast enhancement. CONCLUSION: Subtraction dynamic MR imaging may be helpful to rule out malignancy in nonpalpable breast tumors.

Adult↗
PubMed1994

Locally advanced breast cancer: contrast-enhanced subtraction MR imaging of response to preoperative chemotherapy.

PURPOSE: To determine the value of contrast material-enhanced subtraction magnetic resonance (MR) imaging in assessment of response to chemotherapy in locally advanced breast cancer. MATERIALS AND METHODS: Eighteen women treated with chemotherapy because of locally advanced breast cancer underwent preoperative MR examination including both routine and dynamic MR sequences after injection of gadolinium tetraazacyclododecanetetraacetic acid. Any early contrast enhancement, concomitant with early vascular enhancement during the dynamic MR study, was considered pathologic. RESULTS: Dynamic MR studies showed early contrast enhancement in all women with residual tumor except one with nodular residual tumor. Histopathologic analysis and dynamic MR images of contrast-enhanced lesions correlated well, but in one patient, intraductal extension was not seen on MR images, and in another, additional isolated tumor cells were seen in the histologic specimen. Subtraction images always facilitated visualization of vascular and pathologic contrast enhancement. CONCLUSION: Dynamic MR contrast-enhanced subtraction studies are useful in assessment of residual tumor after chemotherapy.

Adult↗
PubMed1994

Focal areas of increased opacity in ductal carcinoma in situ of the comedo type: mammographic-pathologic correlation.

PURPOSE: To determine a histopathologic explanation for focal areas of increased opacity on mammograms of ductal carcinoma in situ of the comedo type (comedocarcinoma). MATERIALS AND METHODS: From January 1991 to January 1993, mammograms from 36 patients with comedocarcinomas were reviewed. Each mammogram was screened for microcalcifications and/or any focal area of increased opacity. The presence or absence of infiltrating components was confirmed at pathologic examination, with particular emphasis placed on the search for any stromal reaction. RESULTS: The clinical examination revealed a palpable tumor in five patients (14%) and a bloody discharge from the nipple in two (5%). Isolated clusters of microcalcifications were seen at mammography in 24 patients (67%). Nine patients (25%) had clusters associated with focal areas of increased opacity; three patients (8%) had no microcalcifications. Histologic analysis demonstrated an intense, periductal, inflammatory reaction in all 12 patients with focal areas of increased opacity. CONCLUSION: Focal areas of increased opacity are not always indicative of an infiltrating component and may merely represent intense stromal reaction.

Adult↗
PubMed1993

Polyhedral microcalcifications at mammography: histologic correlation with calcium oxalate.

Pathologists have associated calcium oxalate dihydrate (weddellite) in breast biopsy specimens with benign or borderline lesions and rarely with malignancy. These microcalcifications may have a polyhedral shape in histologic specimens owing to their crystalline structure. A retrospective radiologic-histologic correlation study was performed on 300 clusters of microcalcifications to determine if microcalcifications with a polyhedral shape could be found at mammography. In 19 cases (6.3%), polyhedral microcalcifications (PMs) were detected by two radiologists. In 12 of these 19 cases, weddellite crystals were found in the histologic specimen under polarized light; in seven cases, no calcification was found. Although rare, PMs can be found at mammography by radiologists aware of their existence. They are due to weddellite crystals and in this series were associated with benign disease in 89% of cases. Prospective studies are required to determine the frequency of PMs on screening mammograms and to evaluate their negative predictive value.

Breast↗
PubMed1993

Assessment of breast cancer recurrence with contrast-enhanced subtraction MR imaging: preliminary results in 26 patients.

Local relapse was suspected in 26 women treated conservatively for breast cancer. All women underwent routine magnetic resonance (MR) imaging and a dynamic MR subtraction study after injection of gadolinium-tetraazacyclododecanetetra-acetic acid. Twelve women had no local relapse. Surgical biopsy enabled confirmation of recurrence in 14 patients. Routine MR imaging did not allow differentiation of recurrence from glandular or scar tissue. Except for one case of fat necrosis, patients without local relapse showed no contrast enhancement 1 minute 34 seconds after injection. At dynamic MR imaging, all recurrences showed contrast enhancement 1 minute 34 seconds after injection. Nodular enhancement (n = 11) was found in invasive carcinoma, whereas linear enhancement was seen in intraductal carcinoma (n = 3). Subtraction of precontrast from postcontrast images always allowed better visualization of contrast enhancement. Contrast-enhanced subtraction dynamic MR imaging may prove to be accurate in diagnosis of local relapses of breast cancer.

Adult↗
PubMed1993

Case report: clear cell adenocarcinoma of the vagina: MR features.

Clear cell adenocarcinoma (CCA) of the vagina and the cervix is a rare tumour. Since 1971 its increased incidence has been ascribed to intrauterine exposure to diethylstilboestrol (DES) and as a consequence the US Food and Drug Administration has banned the use of all DES-type medications during pregnancy. We report a case of CCA demonstrated by magnetic resonance imaging.

Adenocarcinoma↗
PubMed1992

Imaging in the follow-up of soft tissue tumors.

Local recurrences of aggressive soft tissue tumors are frequent and very difficult to detect clinically after surgery and radiation therapy. Ultrasound is limited because the skin is thick. On contrast-enhanced CT, both scars and recurrences increase their signal. MRI is the best technique, and the only one we presently use in the detection of recurrent tumors. We are reporting 511 follow-up examinations in 182 patients after tumor removal. All patients had histologic confirmation or at least 6 months follow-up. There were 164 malignant tumors and 18 cases of aggressive fibromatosis.

Contrast Media↗
PubMed1991

Volume regulation in rat pheochromocytoma cultured cells submitted to hypoosmotic conditions.

The mechanisms at work in cell volume regulation have been studied in PC12 cultured cells. Results show, for the first time to our knowledge, that the volume readjustment process occurring after application of a hypoosmotic saline is sensitive to amiloride, IBMX and forskoline. The process is also inhibited by quinine hydrochloride and trifluoperazine. Volume readjustment is concomtant with a decrease in K+ and Cl- intracellular levels. The decrease in K+ level can be related to an assymetrical change in the fluxes in and out of the ion as shown by flux kinetics studies using Rb86. These results are interpreted considering that the control of the activity of the ion channel pathways associated with volume readjustment in PC12 cells may implicate the Ca(2+)-calmodulin - cAMP system.

1-Methyl-3-isobutylxanthine↗
PubMed1990

Comparative studies of volume restoration following cold-stress induced swelling in renal tissues--I. Effects of ouabain, K+ free medium, colchicine and cytochalasin B on rat and rabbit kidney cortex slices.

1. Cold-stress-induced swelling in rabbit and rat kidney cortex slices cannot be due to the sole inhibition of a Na+/K+ exchange system. In these tissues indeed, ouabain induces no swelling and an exchange of Na+ for K+ or a l/l basis. Inhibition of K+ extrusion at low temperature has also to be taken into consideration. 2. Volume restoration at 27 degrees C after cold-stress-induced swelling is inhibited by ouabain in rabbit slices, not in rat ones. The inhibition in rabbit slices is concomitant with an increase in Na+ at levels higher than equilibrium with the external medium. 3. Volume restoration does not seem to implicate colchicine or cytochalasin B sensitive processes.

Animals↗
PubMed1990

Comparative studies of volume restoration following cold-stress induced swelling in renal tissues--II. Effects of furosemide, amiloride and K+ permeability in rabbit cortex slices.

1. Inhibition of volume restoration by ouabain in rabbit kidney cortex slices is related to an increase in Na+ concentration which may reach levels higher than equilibrium with the external medium. 2. The uphill accumulation of Na+ is not sensitive to amiloride and furosemide. It is dependent on the level of K+ in the external medium. 3. Bringing the slices from cold to normal temperature induces a large increase in Rb86 efflux. 4. It is concluded that the Na+ entry inhibiting volume restoration is driven by an increase in K+ expel occurring upon tissue rewarming.

Amiloride↗
PubMed1990

[Effect of long-term administration of vasodilators and "antitrophic" agents on the structure and function of the heart in hypertensive rats].

In this study, we determined whether the persistency of cardiac hypertrophy after chronic vasodilation therapy with minoxidil (minox) was associated with functional or metabolic alterations in hypertensive rat hearts before, during and after an ischemic insult. In addition, we investigated the effects of the simultaneous administration of difluoromethylornithine (dfmo), a substance that could block hypertrophy by a direct inhibition of protein synthesis. Four groups of male Wistar rats were prepared: 1) normotensive controls (n = 8), 2) untreated renovascular hypertensive rats (HT, n = 15), 3) hypertensives treated with minox (8 mg/kg, n = 19), 4) hypertensives treated with minox and dfmo (1.7 g/kg, n = 20). After 21 days of treatment, the animals were sacrificed. In a small number of hearts, ornithine decarboxylase (ODC) activity was assayed in order to verify that dfmo, which is a suicide inhibitor of ODC, had effectively interrupted the polyamines pathway. The other hearts were prepared for retrograde perfusion at 35 degrees C and at constant flow (10 ml/min x g). Cardiac function was monitored via the balloon inserted in the left ventricle (LV) and the following protocol was applied: a) baseline period (24 min), b) ischemia (24 min), c) recovery (36 min). Finally, the hearts were weighed and LV wall thickness and inner radius were measured. Blood pressure was maintained near normotension in the two treated groups. Mean systolic pressure (in mmHg) was 145 +/- 4 with minox and 144 +/- 3 with minox + dfmo versus 181 +/- 4 in the HT group (p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Glycine and other amino compounds prevent chromatin precipitation at physiological ionic strength.

Glycine, proline and taurine, when present in the range 0.1-0.60 M, inhibit chromatin precipitation by sodium chloride. Histone gel electrophoresis revealed that the linker histones H1 and H5 were largely depleted from the supernatant chromatin fraction at 0.2 M NaCl, while this depletion was absent in the presence of glycine. These observations are discussed in relation with the various factors which may be involved in the precipitation process.

Adrenal Gland Neoplasms↗
PubMed1988

Measurement of 3':5'cyclic AMP in biological samples using a specific monoclonal antibody.

A fast and sensitive radioimmunoassay for 3':5'cyclic AMP based on a monoclonal antibody has been worked out. Mice were immunized with protein-conjugated 2'-O-succinyl-3':5'-cyclic AMP. The monoclonal antibody detects 0.1 and 1 pmole cAMP with succinyl cAMP (125I)iodotyrosine methyl ester and (3H) cAMP, respectively, as tracers. It shows no cross-reactivity to other adenosine nucleotides up to the millimolar range; cGMP interferes only if present at a 500 fold excess. Plant and animal tissue samples as well as adenylate cyclase activity were analysed directly or after appropriate purification in case of interfering substances. Cyclic AMP levels measured in various tissues by the antibody binding assay correspond to those obtained by HPLC determination using fluorescent etheno-cAMP.

Adenylyl Cyclases↗
PubMed1988

Relations between cell volume control, microfilaments and microtubules networks in T2 and PC12 cultured cells.

The possible relations between cell volume, microfilaments and microtubules networks have been studied in cultured mice fibrosarcoma cells of line T2 and rat pheochromocytoma cells of line PC12. The obtained results show that: 1. Changes in volume induced by application of hypo-osmotic medium are concomitant with a modification in the organization of the microfilaments network as visualized by immunocytochemistry. The microtubules lattice is not affected in these conditions. 2. Disruption of the microfilaments network by cytochalasin B causes a significant decrease in cell volume in isosmotic conditions. It also deeply affects the volume regulation response of cells swollen in hypo-osmotic media. 3. Disruption of the microtubules lattice by colchicine has no effect on volume in isosmotic conditions nor on the volume regulation that follows application of hypo-osmotic shock. The possible role of microfilaments in cell volume control is discussed.

Actin Cytoskeleton↗