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Biomedical subjects

J J Michels

Publications and source records attributed to J J Michels.

At least 19 recordsLinked to original sources
PubMed2006

[Vacuum-assisted stereotactic biopsy: experience of the regional cancer center of Caen].

PURPOSE: To report our experience with macrobiopsy under stereotaxy. MATERIALS AND METHODS: Retrospective study of 248 procedures in 236 patients for microcalcifications in 95% of cases. The macrobiopsies were performed under Mammotome for lesions graded ACR 3, ACR 4 and ACR 5 in 8.4%, 81.6% and 14.8% of cases respectively. RESULTS: From a technical point of view, 91% of procedures had no technical problem. The image guided excision was complete in 68% of cases with lesions less than 1 cm in size and in 6% of cases for lesions larger than 1 cm. The rate of a misdiagnosis of ductal carcinoma in situ for patients with invasive carcinoma was 27% whereas the rate of a misdiagnosis of atypical ductal hyperplasia in patients with ductal carcinoma in situ was 25% knowing that patients with atypical ductal hyperplasia for which all microcalcifications had been fully removed by macrobiopsy and without risk factors did not undergo surgery. CONCLUSION: Even if macrobiopsy of microcalcifications is a reliable method, its main limitation remains the risk of misdiagnosis of borderline lesions.

Biopsy, Needle↗
PubMed2003

Double immunohistochemical labeling technique applied to different types of cytokeratins in epithelial proliferations of the breast.

The double labeling technique using peroxidase and alkaline phosphatase for immunohistochemistry is well known, but must be adapted according to the antibodies used, fixation, and technical conditions. The technique allows identification on one slide of two antigens that are localized in the same or different cells of the same lesion. The aim of this paper is to describe the adaptation of this technique to cytokeratins of normal mammary tissue and proliferative lesions of the breast.

Animals↗
PubMed2001

Improved measurement of formaldehyde in water-soluble polymers by high-performance liquid chromatography coupled with post-column reaction detection.

An improved methodology for the analysis of free formaldehyde in water-soluble polymers used for industrial water treatment is reported. Previously, derivatization prior to HPLC or colorimetric techniques has been used. The data generated by these approaches are suspect in that the derivatizing agent can react with the polymer or other sample components to produce high results. Post-column reaction derivatization is applied after separation of the free formaldehyde from the product interferences. The type of polymer product analyzed influences the choice of column(s). The degree of high bias of the commonly used 2,4-dinitrophenylhydrazine pre-column derivatization is reported and the results are compared to those with the post-column reaction for two polymer products. This method, being more selective, should be applicable to any polymer containing formaldehyde.

Chromatography, High Pressure Liquid↗
PubMed2001

Reaction of acylated homoserine lactone bacterial signaling molecules with oxidized halogen antimicrobials.

Oxidized halogen antimicrobials, such as hypochlorous and hypobromous acids, have been used extensively for microbial control in industrial systems. Recent discoveries have shown that acylated homoserine lactone cell-to-cell signaling molecules are important for biofilm formation in Pseudomonas aeruginosa, suggesting that biofouling can be controlled by interfering with bacterial cell-to-cell communication. This study was conducted to investigate the potential for oxidized halogens to react with acylated homoserine lactone-based signaling molecules. Acylated homoserine lactones containing a 3-oxo group were found to rapidly react with oxidized halogens, while acylated homoserine lactones lacking the 3-oxo functionality did not react. The Chromobacterium violaceum CV026 bioassay was used to determine the effects of such reactions on acylated homoserine lactone activity. The results demonstrated that 3-oxo acyl homoserine lactone activity was rapidly lost upon exposure to oxidized halogens; however, acylated homoserine lactones lacking the 3-oxo group retained activity. Experiments with the marine alga Laminaria digitata demonstrated that natural haloperoxidase systems are capable of mediating the deactivation of acylated homoserine lactones. This may illustrate a natural defense mechanism to prevent biofouling on the surface of this marine alga. The Chromobacterium violaceum activity assay illustrates that reactions between 3-oxo acylated homoserine lactone molecules and oxidized halogens do occur despite the presence of biofilm components at much greater concentrations. This work suggests that oxidized halogens may control biofilm not only via a cidal mechanism, but also by possibly interfering with 3-oxo acylated homoserine lactone-based cell signaling.

4-Butyrolactone↗
PubMed2000

Degradation pathway of homoserine lactone bacterial signal molecules by halogen antimicrobials identified by liquid chromatography with photodiode array and mass spectrometric detection.

The degradation pathway of acylated homoserine lactone bacterial signaling molecules by oxidizing hypochlorite and stabilized hypobromite antimicrobials has been characterized. A reversed-phase HPLC separation using a cyano column was developed to detect the parent lactones, lactone-hydrolysis products, and halogenation products. Elucidation of the structures of the reaction products was done with the aid of online photodiode array UV spectroscopy and atmospheric pressure chemical ionization mass spectrometry. Quantitative output of the HPLC method was also used to estimate the kinetics of the degradation pathway. The results of this work found that only beta-keto-amide signal molecules are halogenated, where normal amide signals are not, and may represent one possible mechanism for control of industrial biofilms.

4-Butyrolactone↗
PubMed2000

Variation of flow cytometric DNA measurement in 1,485 primary breast carcinomas according to guidelines for DNA histogram interpretation.

From 1990-1996, 1,485 previously untreated invasive breast carcinomas were sampled by a pathologist for flow cytometric DNA analysis. The aim of the present work was to study the variations of flow cytometric DNA ploidy and S-phase evaluation according to the conditions of DNA histogram interpretation. Results obtained with the American Consensus guidelines of 1993 and the François Baclesse Department of Pathology's own guidelines are presented. According to the percentage of events taken into account to identify a DNA aneuploid peak, the proportion of DNA diploid cases can change from 35-39%. For S-phase evaluation, although the two guidelines were quite different, the results of S-phase cutoff were identical. Whichever guidelines were used, there was a strong relationship between DNA ploidy and/or S-phase and classical clinicopathological factors (T, N, histological type, grade, receptor status, or lymphatic invasion), with the exception of age, whose correlation was discrepant with S phase according to the set of guidelines. Whichever guidelines were used, ploidy and S phase correlated strongly with survival (overall, metastasis-free, or recurrence-free). Hence we recommend the use of the American consensus guidelines, despite minor imperfections, because they are now well-known, allow a high yield in the ratio of assessable S phases, and permit standardization in the technical processing and reporting of S phases, thanks to the use of terciles.

Aneuploidy↗
PubMed2000

Flow cytometry in primary breast carcinomas. Prognostic impact of proliferative activity.

From 1990 to 1996, 607 previously untreated, node-negative, invasive breast carcinomas were sampled by a pathologist for flow-cytometric DNA analysis. The aim of the present work was to study the correlations between flow cytometric results obtained thanks to the American Consensus (AC) guidelines of 1993 and the established clinico-pathological prognostic factors (T, grade, receptors), and despite a short global follow-up (mean of 4 years), to correlate flow cytometry with the outcome of the patients. In this study S-phase fraction (SPF) correlated strongly with tumor size, histological grade, lack of steroid receptors, histological type and was together with the mitotic activity a paramount prognostic factor even after multivariate analysis. This study compared also the technical criteria proposed by the AC with our own more stringent ones and concluded that the criteria of the AC are relevant and allow, thanks to the use of tertiles in the reporting of SPF values, a comparison of values obtained by different teams. Our review of the literature, focused on series using fresh material, enabled us to show that there is a rather wide agreement concerning the relationship between SPF and prognosis most often after multivariate analysis. This despite the lack of standardization in the design of the studies (implementation of the technical steps or reporting of results). When estimated from fresh or frozen material following AC's guidelines. SPF along with mitotic activity should become a prognostic factor used in the daily practice by oncologists in the management of breast carcinomas.

Adult↗
PubMed2000

[Atypical prostatic leiomyoma: a new case with cytodensitometric analysis].

Atypical prostatic leiomyoma is a very rare benign tumor. We report here a new case with a cytodensitometric analysis. The result of cytodensitometry is a polyploid tumor that is well correlated with the morphology of nuclear multilobulated cells of this tumor. The differential diagnosis is essentially the leiomyosarcoma which is characterized by the absence of mitotic activity.

Aged↗
PubMed1997

[Flow cytometry in ORL cancers].

The possibility to perform flow cytometry was examined in a series of 167 patients with primary untreated head and neck carcinoma referred to our Institution from February 1989 to January 1992. In all cases, flow cytometry was carried out on frozen tumour samples. The Cox model was used including age, tumour size, nodal status on clinical assessment, topography, treatment, malignancy grade, S phase fraction and ploidy as independent variables and overall survival as dependent variable. In this study, ploidy could be assessed in only 73% of cases and S phase fraction and G2M in 65% of the population studied. No correlation could be evidenced between ploidy or SPF with other clinical, pathologic characteristics or clinical outcome. We conclude that flow cytometry should remain a research tool until the method has proved to be relevant in clinical routine, and until the yield of the technique can be improved.

Adult↗
PubMed1997

[Neuroblastoma arising in testicular teratoma].

One case of neuroblastoma arising in an adult immature testicular teratoma is described, with multiple systemic metastases, a partial response to intensive chemotherapy and a swift recurrence leading to death. Such instances of prevailing neuroblastoma with systemic metastases, have only seldomly been reported hitherto. Because of the teratoma and the focal presence of intratubular germ cell neoplasia of unclassified type, we think this tumor must be indeed of germ cell derivation.

Adult↗
PubMed1995

[Extemporaneous histologic examination of cutaneous carcinoma of the face].

One hundred thirty-eight skin cancers of the face were reviewed retrospectively in order to evaluate the extemporaneous histology examination. The results obtained were satisfactory and in agreement with those in the literature. This technique is perfectly adapted to cancers with a facial localization. In our opinion, the indication for extemporaneous examinations should be widened to all cases of epithelioma of the face.

Aged↗
PubMed1990

Estimation of the reversed-phase liquid chromatographic lipophilicity parameter log k'w using ET-30 solvatochromism.

The estimation of the reversed-phase liquid chromatographic lipophilicity parameter log k'w has been studied using the solvatochromic ET(30) polarity scale. Over 200 sets of chromatographic retention data were used to compare the log k'w estimates made from the volume percent of organic modifier (%) and ET(30) models of mobile phase strength. It was found that linear extrapolations of log k' versus ET(30) plots to the polarity of unmodified aqueous mobile phase gave a more reliable value of log k'w than linear regressions of log k' versus volume percent. This evaluation was based upon the relative value of the 95% confidence interval about log k'w, the point of intersection of log k' versus solvent strength plots for different modifiers, the scatter of estimations with different modifiers and the goodness-of-fit of the data to the linear model. Estimations of log k'w using the solvatochromic approach are found to give a more sensitive lipophilicity description than the volume percent approach. Recommended procedures for carrying out lipophilicity estimations with reversed-phase liquid chromatography are also discussed.

Chromatography, High Pressure Liquid↗
PubMed1988

Retention in reversed-phase liquid chromatography: solvatochromic investigation of homologous alcohol-water binary mobile phases.

The mechanism of retention in reversed-phase liquid chromatography (RPLC) has been further investigated using the ET(30) solvatochromic solvent polarity scale. The retention behavior of a variety of solutes was measured using a homologous series of normal alcohols as the organic modifiers in hydroorganic mobile phases. The results imply that a systematic change in the extent of solvation of the stationary phase occurs with respect to the size of the organic modifier. It was also found that a linear extrapolation of the log k' versus ET(30) plots for different mobile phases using methanol, ethanol and acetonitrile (but not n-propanol) as modifiers, intersected at approximately the ET(30) value of pure water. This intersection is further evidence that the ET(30) model of solute retention is a useful tool with which to study the mechanism of retention in RPLC. The extrapolated retention value in water, log k'w, from the ET(30) plots should then prove to be a more reliable means of estimating solute lipophilicity using RPLC than the percent organic modifier model.

Alcohols↗
PubMed1983

[Concept policy plan nursing homes].

The concept report of the administration of the Section Nursing homes of the National Council of Hospitals: 'A policy plan on nursing homes', is reviewed. The conclusion is that the report overestimates the possibilities of nursing home care. This institution is insufficiently equipped for geriatric diagnosis and therapy, for multidisciplinary screening and for supporting home care. The attention paid to the psychogeriatric patient in the plan is insufficient. Views are expressed on, not by the patients, and too much is expected from bureaucratic arrangements. It is a good starting point for discussion.

Health Facilities↗