Biomedical subjects
Publications and source records attributed to R Gilles.
Imaging is crucial in early diagnosis of breast cancer. Mammography is still the most simple and reproducible method, except in dense breast. In these circumstances, ultrasonography may be helpful. Magnetic resonance imaging has some indications such as the diagnosis of local relapses and preoperative staging.
AIM: To determine the accuracy of dynamic contrast-enhanced subfraction MRI to diagnose nonpalpable breast lesions in a prospective multicenter study. MATERIAL AND METHODS: From June to November 1994, 72 patients had a surgical biopsy for a nonpalpable breast lesion and a preoperative dynamic MR after an informed consent was obtained. MR examinations were performed on 0.5, 1 and 1.5T MR unit. Each center underwent dynamic sequences either in spin or gradient echo in T1 weighted images obtained in less than two minutes before and after injection of Gadolinium-DOTA. The presence/absence of contrast enhancement within two minutes after injection of Gadolinium were considered as positive/negative findings respectively. RESULTS: These 72 women had mammographic (n = 80) or ultrasonographic lesions (n = 2). Mammograms showed mass (n = 23), asymmetrical density (n = 2), architectural distorsion (n = 8), clustered microcalcifications (n = 47) or was normal (n = 2). Dynamic Breast MR imaging showed early contrast enhancement in 44 malignant lesions (sensitivity: 89.8%) and 13 benign lesions (specificity: 60.6%). Five intraductal carcinoma of comedo (n = 1) or non-comedo (n = 4) type did not demonstrate any early contrast enhancement. CONCLUSION: This prospective mulcentric study confirms the high sensitivity of dynamic breast MRI whatever the type of MR unit or sequences.
The authors report a case of tricuspid blood culture-negative endocarditis where serologic investigations showed high titers of antibodies against. Chlamydia pneumoniae, thus suggesting its possible role as the causal agent. The treatment consisted of polymicrobial therapy using ciprofloxacine and doxycycline with favorable response thus avoiding surgical intervention. In all cases of culture-negative endocarditis not responding to classic empiric antibiotics, Chlamydia infection should be suspected. Although rare cases of endocarditis due to Chlamydia pneumoniae have been reported in the literature, to our knowledge, this is the first case of isolated tricuspid valve endocarditis due to this agent to be reported.
L-929 cells acclimated to media made hyperosmotic (600 mosmol/kgH2O) by addition of NaCl, sorbitol, or mannitol show, on SDS-polyacrylamide gels, a markedly enhanced protein band at 40 kDa, most likely corresponding to the enzyme aldose reductase. The effect was not observed in cells acclimated to a medium rendered hyperosmotic by addition of proline. The major organic osmolyte accumulated is sorbitol in cells acclimated to high-sorbitol or high-NaCl medium, proline in cells acclimated to high-proline medium. Cells acclimated to any of these hyperosmotic media display unaltered Na+ levels and similarly increased K+ levels and decreased Cl-levels. These results are interpreted in terms of the mechanisms involved in aldose reductase induction and in regulation of the enzyme activity in long-term acclimation to hyperosmotic media.
The Trasylol manufacturing process was investigated with respect to its capacity for the inactivation/removal of infectivity causing bovine spongiform encephalopathy (BSE). Four process steps were selected for this investigation and scaled down to laboratory scale. Authentic samples of bovine lungs used in the Trasylol manufacturing plant were taken and spiked in laboratory scale experiments with high infectious titres of the rodent adapted scrapie strain ME 7 which served as model for BSE. After performing the respective process steps the output samples collected were tested in C57BL mice carrying the Sinc gene. An overall reduction of the infectious agent in the order of 18 log10 was observed, indicating a very high capacity of the Trasylol process for the inactivation/removal of the BSE/scrapie agent. The discussed safety strategy for the product leads to the conclusion that Trasylol is BSE safe.
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PURPOSE: To assess contrast material-enhanced computed tomography (CT) of breast for diagnosing local recurrence after conservative therapy. MATERIALS AND METHODS: In 111 patients, 118 lesions were evaluated with unenhanced and enhanced CT. Criterion for cancer recurrence was detection of a lesion with an enhancement of 45 HU or more. RESULTS: One group comprised 52 lesions with pathologic diagnoses, obtained within 1 month of CT, of malignancy in 43 and benignancy in nine. Scans were positive in 40 of 43 recurrences and negative in six of nine benign lesions. Seventeen recurrent lesions were nonpalpable, and contrast-enhanced CT results were true-positive in 15 of these. A second group comprised 66 lesions with a mean follow-up of the treated breast of 28 months after CT. In 56 lesions, the scans were negative, with no recurrence in 55; local recurrence was proved with a 14-month delayed surgical biopsy in one. In 10 lesions, scans were positive, with a delayed diagnosis of recurrence 5 and 6 months after CT in two and no evidence of recurrence in eight (false-positive results). The sensitivity of breast CT for both groups was 91% (42 of 46 lesions) with a specificity of 85% (61 of 72 lesions). CONCLUSION: Contrast-enhanced CT is sensitive in the diagnosis of local recurrence of breast cancer, even in nonpalpable lesions, and may be a useful tool in patients with equivocal clinical and/or mammographic findings during follow-up after conservative therapy.
Fourty-four CT-guided adrenal biopsies were performed on 43 patients aged 12-74 years old (mean 57 years). The results (benign adrenal tissue, malignant tissue, and nondiagnostic) were compared with outcomes. Diagnostic samples were obtained in 86% of patients. Among the 37 proved cases with diagnostic results (10 benign, 27 malignant), there were 26 true-positives, 1 false-negatives and 10 true-negatives. CT-guided adrenal biopsy had an accuracy of 82%, a sensitivity of 96%, a negative predictive value of 83%. In the 6 patients with nondiagnostic samples 1 mass proved malignant and two masses proved benign. Seven minor complications occurred in 7 patients (6 pneumothoraces and 1 retroperitoneal hemorrhage). CT-guided adrenal biopsy is a simple safe and well tolerated technique. In oncologic patients, obtaining benign adrenal tissue was highly predictive of benignity.
L929 and MDCK cells acclimated to sorbitol, proline or taurine media can tolerate a NaCl load that they would be unable to stand when cultured in normal conditions. The protecting effect is observed only at high concentrations, between 100 and 300 mM. In that range, the effect is increasing with increasing concentration. The presence of the compound is not necessary, in the extracellular medium, to induce tolerance. These results are discussed in the framework of the theory considering preferential interactions of proteins with solvent components to explain the protecting effect of such compounds.
Kidney medulla cells of mammals have to cope with large changes in environmental osmolarity, a challenge most other mammalian cells never have to experience. In these last cells, application of osmotic shocks induces dramatic modifications in chromatin organization. The present paper reports on the changes of medulla cell chromatin in situ, in rat kidney slices submitted to osmotic challenges and in vitro, on preparations of extracted chromatin submitted to changes in environmental ion concentrations. Our results show that the chromatin of kidney medulla cells: (1) does not behave differently from the other mammalian chromatins when submitted in situ or in vitro to osmotic challenges; (2) presents in vitro physico-chemical characteristics similar to those of the other mammalian chromatins; and (3) is protected in vitro, as the other mammalian chromatins, from the disrupting effects of increases in inorganic ion concentrations by different compensatory organic solutes. The ability of kidney medulla cells to adapt to large increases in osmolarity could thus be related to a rapid control of the level of such compounds rather than to some rather specific, intrinsic molecular adaptations of macromolecules.
Application of abrupt, large hyperosmotic shocks induces in L929 cultured cells changes similar to those previously described in other cell types, notably a hypercondensation of the nuclear chromatin. This paper shows that; 1) this phenomenon is concomitant with a complete disappearance of deoxyribonucleic acid, as visualized by immunogold labelling, from the nucleoplasmic spaces; 2) acclimation to high osmolarities (600 mOsm) by addition to the culture medium of NaCl, sorbitol or proline protects the cells from these effects, which appear to be largely attenuated-acclimated cells also survive much better to the osmotic shock than do control cells and; 3) the best protection seems to be provided by sorbitol and NaCl. Proline acclimation is less effective. These effects are discussed in terms of increased tolerance to NaCl load induced at the level of different macromolecules by so-called 'compensatory' organic compounds.
BACKGROUND: Previous studies have suggested combining magnetic resonance (MR) imaging and biopsy in patients with lymphoma but association between MR results and clinical symptoms have never been investigated. The purpose of this retrospective study was to better delineate patients profiles requiring bone marrow (BM) imaging in lymphoma. MATERIAL AND METHODS: 50 MR studies and blind biopsies (BB) were reviewed in 40 patients with lymphoma. MR results were compared to clinical, laboratory-based and BM follow-up data to determine potential associations between MR results and these parameters. RESULTS: 46% of MR studies were abnormal with a normal BB; 2% were normal with an abnormal BB. Abnormal MR results were significantly associated with subsequent bone marrow involvement (p < 0.01). Abnormal MR studies were significantly associated with constitutional symptoms, bone pains (p < 0.05) and an elevated alkaline phosphatase level (p < 0.01). MR imaging excluded malignancy in three patients and caused therapy to be modified in three. CONCLUSION: Abnormal clinical and laboratory-based data should be used to screen patients with normal BB for MR imaging, especially in patients with Hodgkin's disease and high grade non-Hodgkin's lymphoma.
This paper presents a computerized method for the automated segmentation of individual microcalcifications in a region of interest (ROI) known to contain a cluster in digital mammograms. Mammographic parenchyma caj be accurately modeled with the fractal approach, but not areas with microcalcifications. The digitized image is divided into 16 x 16-pixel overlapping windows and those accurately modeled by the fractal model are eliminated. The next steps include local thresholding of the ROIs using an iterative method, the elimination of some of the artifacts and identification of the clustered microcalcifications using a clustering algorithm. The evaluation was performed on 81 simulated clusters superimposed on normal mammographic backgrounds and on a representative database of 408 real mammograms. Microcalcification locations were identified by two radiologists independently. These locations were compared to those found by the computer algorithm. An average of 59% of the simulated microcalcifications and 69% of the microcalcifications common to both radiologists were detected. The algorithm described provides a fully automated method for the segmentation of individual microcalcifications in an area of the mammogram known to contain a cluster.
PURPOSE: To correlate histopathologic and magnetic resonance (MR) imaging findings of ductal carcinoma in situ (DCIS). MATERIALS AND METHODS: Thirty-six women with DCIS underwent preoperative contrast material-enhanced subtraction dynamic MR imaging. Concomitant early contrast enhancement in the breast parenchyma with normal vessels was considered a positive finding. The size and shape of early enhancement were correlated with the size and density packing of ducts involved by DCIS. Tumor angiogenesis in the stroma that surrounded the ducts was evaluated with immunoperoxidase staining. RESULTS: Early contrast enhancement was demonstrated in 34 patients with DCIS but not in two patients with comedo-type DCIS. Tumor angiogenesis was demonstrated in the stroma. The size and morphology of contrast-enhanced lesions significantly correlated with the size (P = .0085) and density packing of ducts involved by DCIS (P = .012). CONCLUSION: Contrast enhancement on dynamic MR images of DCIS may be due to the presence of tumor angiogenesis in the stroma.
The aim of this study is to determine the diagnostic value of magnetic resonance imaging in the diagnosis of local recurrence of breast cancer. From 1991 to 1994, 61 women were studied prospectively using magnetic resonance imaging. All examinations were made on a 1.5 Testa machine with T1 weighted images and after gadolium-dota injection and dynamic images (T1 weighted sequences every 47 seconds during injection of a gadolinium-dota bolus). All the pre-injection, images in the dynamic series were subtracted from the images after injection. A surgical biopsy was obtained in 39 patients yielding a diagnosis of local recurrence (n = 28) or a benign lesion (n = 11). Among the 28 local recurrences, pathology examination reported invasive cancer in 22 and intra-ductal carcinoma in 6. In 22 patients with normal magnetic resonance imaging, follow-up examinations were performed every 6 months. There were no local recurrences within a delay of 6 to 36 months. Twenty-six of the 28 patients with a local recurrence, cystosteatonecrosis and surgery scar tissue less than 6 months old showed contrast uptake 1 min and 34 s after gadolinium injection during the dynamic sequence. This product uptake yielded nodular images within the invasive carcinomas and linear images in the intraductal cancers. In all cases, it is easier to visualize this contrast uptake in subtraction images. In conclusion, magnetic resonance imaging is a simple reliable method for the diagnosis of local recurrence of breast cancer.
Between 1984 and 1990, 16 children who had been treated for a histologically proven head and neck rhabdomyosarcoma developed 19 local recurrences. Fourteen relapses discovered in 11 children (group 1) were based on clinical data acquired 3 to 52 months after completion of treatment. Clinical symptoms (12 patients) or examination (2 patients) led to suspicion of a relapse. The clinical presentation of relapses and that of primary tumour were identical in eight cases. CT scans performed prior to recurrence revealed a stable 'post-therapeutic residue' without mass effect at the original site (12 patients) or was normal (2 patients). Six of these 11 children died at 1 to 15 months and five are alive 12 to 36 months after treatment of recurrence. Five relapses were discovered on CT studies 3 to 15 months after completion of treatment in the remaining five children (group 2). Clinical examination was normal in all cases. CT scans performed 3 months before recurrence showed a stable 'post-therapeutic residue' (4 patients) or was normal (1 patient). All of these five children died 3 to 23 months after the relapse.
A simulation model of clustered microcalcifications superimposed on normal mammographic backgrounds has been developed and evaluated. A cluster is described according to its size, the number of microcalcifications it contains, and their density. A microcalcification is defined on the basis of its size, shape, location within the cluster, its contrast, and the distribution of the gray-level values between pixels that belong to it. Gray-level parameters are dependent on the surrounding tissue, which is also slightly modified. The main dependencies between the parameters are taken into account. All the parameters are randomly sampled using distribution laws determined from the statistical analysis of 408 real clusters containing a total of 8611 microcalcifications. Some statistical characteristics depend on the structural mammographic pattern on which the cluster is superimposed. The evaluation of the simulation model, performed by two radiologists on a test set of 100 real and simulated clusters, did not reveal any statistically significant difference between the simulated clusters and the real ones. This method provides clusters of microcalcifications with well-defined characteristics and can be used to evaluate the accuracy of computerized detection methods.
PURPOSE: To present magnetic resonance (MR) imaging findings from 511 follow-up examinations of aggressive soft-tissue tumors. MATERIALS AND METHODS: One hundred eighty-two patients with aggressive soft-tissue tumours underwent postoperative T1- and T2-weighted imaging; 41 also underwent 51 gadolinium-enhanced T1-weighted examinations, and five underwent dynamic gadolinium-enhanced subtraction imaging. RESULTS: Twenty-four of 25 patients (101 of 102 examinations) without high signal intensity (HSI) at T2-weighted imaging had no recurrence. Among 79 patients (321 examinations) who demonstrated HSI without a mass, only two tumors recurred within 1 year. An HSI mass was found in 88 studies of 78 patients and represented recurrence (n = 60), hygroma (n = 24), or a radiation-induced pseudomass (n = 4). Hygromas did not enhance, while recurrences enhanced at 1-3 minutes and postirradiation change enhanced at 4-7 minutes. CONCLUSION: T2-weighted imaging can be used to identify possible recurrence of aggressive soft-tissue tumors, while gadolinium-enhanced imaging can be used to differentiate recurrences from hygromas and inflammatory change.