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M Auger

Publications and source records attributed to M Auger.

At least 37 records · Page 2Linked to original sources
PubMed1997

Fine-needle aspiration cytology of pleomorphic lobular carcinoma of the breast. Comparison with the classic type.

BACKGROUND: The pleomorphic variant of invasive lobular carcinoma shares the typical infiltrating histologic pattern of classic invasive lobular carcinoma, but differs from it in its nuclear pleomorphism and aggressive behavior. The purpose of this study was to describe the fine-needle aspiration (FNA) cytologic findings of the pleomorphic variant of lobular carcinoma and to compare them with those of classic lobular carcinoma. METHODS: Among 405 breast FNA performed in 1995, 7 examples of classic infiltrating lobular carcinoma and 4 cases of this neoplasm's pleomorphic variant were identified; all were histologically confirmed. The FNA from three of the four pleomorphic variant cases and from two of the seven classic lobular carcinoma cases were diagnostic of malignancy; these were evaluated for a variety of cytologic criteria, which were graded from 0 to 3. RESULTS: Although exhibiting many cytologic features in common with the classic type, such as indian files and cytoplasmic vacuoles, the FNA of the pleomorphic variant differed in their tendency to yield greater cellularity, larger cell size, and, particularly, more pleomorphic nuclei. CONCLUSIONS: The FNA cytologic findings of the pleomorphic variant of lobular carcinoma are characteristically hybrid between those of classic lobular carcinoma and ductal carcinoma.

Biopsy, Needle↗
PubMed1997

Differentiating cytological features of bronchioloalveolar carcinoma from adenocarcinoma of the lung in fine-needle aspirations: a statistical analysis of 27 cases.

Bronchioloalveolar carcinoma (BAC) is an uncommon type of lung carcinoma that is important to distinguish from adenocarcinoma (adenoCA) because of its different biological behavior. Although the features of BAC have often been described in cytological material other than fine-needle aspirations (FNA), they have rarely been detailed in FNA specimens. We undertook to delineate the differentiating cytological features of 13 cases of BAC (7 of the nonsecretory type and 6 of the secretory type) and of 14 cases of bronchogenic adenoCA in FNA material, looking at 17 cytological criteria and using statistical analysis. When statistically analyzed with chi-square and Pearson's correlation, only 3 of the 17 features were found to be good discriminants for distinguishing nonsecretory BAC (NS-BAC) from adenoCA: prominence of monolayered tumor sheets, fine chromatin pattern, and mild cellular pleomorphism correlated significantly with NS-BAC. On the other hand, only the prominence of nuclear grooves and the abundance of extracellular mucin correlated significantly with secretory BAC (S-BAC) when compared to adenoCA. When using a logistic regression analysis, NS-BAC and S-BAC were best discriminated from adenoCA by the prominence of monolayered tumor sheets and by the abundance of extracellular mucin, respectively. We conclude that, in most instances, it is possible to make an accurate diagnosis of BAC and to distinguish it from adenoCA of the lung in FNA material.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1997

Multinuclear solid-state NMR spectroscopy of envelopes from virgin and explanted silicone breast prostheses: an exploratory study.

The structure and dynamics of silicone envelopes from virgin and explanted breast prostheses have been studied by 1H, 13C, and 29Si high-resolution solid-state NMR spectroscopy. The results indicate that this combination of techniques can be used to unambiguously identify the presence of methyltrifluoropropylsiloxane units and diphenylsiloxane units at concentrations of about 2.0% and 3.5%, respectively, in some of the envelopes. The presence of about 10% silica also was detected and a trace of lipids was found in the explanted silicone envelopes. We have also measured the proton T2 and T1 relaxation times of the envelopes to characterize the dynamics of the silicone in the envelopes.

Breast Implants↗
PubMed1997

Membrane structure and dynamics as viewed by solid-state NMR spectroscopy.

The purpose of the present study is the investigation of the structure and dynamics of biological membranes using solid-state nuclear magnetic resonance (NMR) spectroscopy. Two approaches are used in our laboratory. The first involves the measurement of high-resolution 13C and 1H spectra obtained by the magic angle spinning (MAS) technique while the second approach involves the measurement of 31P and 2H powder spectra in static samples. This paper will present some recent results obtained by high-resolution solid-state 1H NMR on the conformation of gramicidin A incorporated in a phosphatidylcholine bilayers. More specifically, we were able to observe changes in the gramicidin spectra as a function of the cosolubilization solvent initially used to prepare the samples. The interaction between lipid bilayers and an anticancer drug derived from chloroethylurea was also investigated using proton NMR spectroscopy. Finally, we have studied the interaction between cardiotoxin, a toxic protein extracted from snake venom, and negatively charged lipid bilayers using 31P solid-state NMR spectroscopy.

Cell Membrane↗
PubMed1996

Interaction of 4-tert-butyl-[3-(2-chloroethyl) ureido] benzene with phosphatidylcholine bilayers: a differential scanning calorimetry and infrared spectroscopy study.

We have investigated the interaction between a new antineoplastic drug, 4-tert-butyl-[3-(2-chloroethyl)ureido] benzene (tBCEU), and distearoylphosphatidylcholine bilayers using differential scanning calorimetry, Fourier transform infrared spectroscopy (FT-IR), and high-pressure infrared spectroscopy. The results obtained with the three different techniques indicate that the drug incorporates in the lipid bilayer. More specifically, the incorporation of the tBCEU results in a decrease in the phase transition temperature of the lipid and in an increase in the amount of gauche conformers in the liquid-crystalline phase. In the gel phase, high-pressure FT-IR results indicate that the incorporation of tBCEU decreases the acyl chain packing. In addition, the results suggest the presence of hydrogen bonding between the lipid carbonyl group and a hydrogen bond donor in the tBCEU molecule. A possible candidate for this donor is the NH group adjacent to the phenyl ring. A model is proposed for the incorporation of tBCEU in lipid bilayers, with the hydrophobic portion of the drug intercalated between the lipid bilayers and the hydrophilic region located close to the interfacial region of the bilayer.

Antineoplastic Agents↗
PubMed1996

Membrane fluidity response to odorants as seen by 2H-NMR and infrared spectroscopy.

Fourier transform infrared spectroscopy (FTIR) and deuterium nuclear magnetic resonance spectroscopy (2H-NMR) have been used to study the location of two odorants, beta-ionone and menthone, in a model membrane of dimyristoylphosphatidylcholine, as well as the effect of the odorants on the structure and dynamics of the phospholipids. The interaction has been investigated for two lipid-to-odorant molar ratios, 10:1 and 1:1. The two odorants were found to affect the fluidity of the membrane. More specifically, the 2H-NMR results indicate that at a lipid-to-odorant molar ratio of 10:1, both beta-ionone and menthone increase the order of the deuterons in the interfacial and headgroup regions of the lipid while the incorporation of the odorants at a lipid-to-odorant molar ratio of 1:1 decreases the order of both the lipid headgroup and acyl chains. On the other hand, the infrared results show that the incorporation of beta-ionone and menthone decreases the phase transition temperature and cooperativity of the lipid acyl chains. The results suggest that the site of incorporation of beta-ionone and menthone is very similar in DMPC membranes.

Dimyristoylphosphatidylcholine↗
PubMed1996

Fine-needle aspiration cytology of ovarian cysts in in vitro fertilization patients: a study of 125 cases.

Fine-needle aspiration (FNA) cytology of ovarian cysts, especially in in vitro fertilization (IVF) patients, has been only rarely reported. The aim of this study was to describe the spectrum of cytological findings seen in FNA specimens of 125 ovarian cysts obtained from 84 IVF patients at our institution from 1989-1993. The Papanicolaou-stained slides made following cytocentrifuge or membrane-filter preparation were reviewed blindly by two independent pathologists, and the consensus diagnoses were compiled and correlated with clinical and radiological findings as well as surgical pathology when available. Eight aspirates derived from 4 different patients contained neoplastic cells and, of these, one patient was later found to have a serous cystadenocarcinoma of low malignant potential, while another had a serous cystadenoma. The other 2 patients with neoplastic cells in their ovarian aspirates have persistent ovarian cysts that are being followed clinically for preservation of fertility. The breakdown of the cytological diagnoses of the other aspirates is as follows: 30 follicular cysts, 5 corpus luteum cysts, and 16 endometriotic cysts. The exact underlying nature of 66 cysts could not be determined as the aspirates consisted of foamy macrophages only. This study demonstrates that the nature of ovarian cysts in IVF patients can be determined in many cases by their cytological features, information that may help in defining an unsuspected cause for infertility (such as endometriosis), and in choosing the most appropriate therapy. This study also illustrates that FNA cytology of ovarian cysts can play a role in the detection of occult ovarian neoplasms in the IVF patients population.

Adult↗
PubMed1996

Model of interaction between a cardiotoxin and dimyristoylphosphatidic acid bilayers determined by solid-state 31P NMR spectroscopy.

The interaction of cardiotoxin IIa, a small basic protein extracted from Naja mossambica mossambica venom, with dimyristoylphosphatidic acid (DMPA) membranes has been investigated by solid-state 31P nuclear magnetic resonance spectroscopy. Both the spectral lineshapes and transverse relaxation time values have been measured as a function of temperature for different lipid-to-protein molar ratios. The results indicate that the interaction of cardiotoxin with DMPA gives rise to the complete disappearance of the bilayer structure at a lipid-to-protein molar ratio of 5:1. However, a coexistence of the lamellar and isotropic phases is observed at higher lipid contents. In addition, the number of phospholipids interacting with cardiotoxin increases from about 5 at room temperature to approximately 15 at temperatures above the phase transition of the pure lipid. The isotropic structure appears to be a hydrophobic complex similar to an inverted micellar phase that can be extracted by a hydrophobic solvent. At a lipid-to-protein molar ratio of 40:1, the isotropic structure disappears at high temperature to give rise to a second anisotropic phase, which is most likely associated with the incorporation of the hydrophobic complex inside the bilayer.

Aniline Compounds↗
PubMed1995

The zinc-binding site of Escherichia coli glutamyl-tRNA synthetase is located in the acceptor-binding domain. Studies by extended x-ray absorption fine structure, molecular modeling, and site-directed mutagenesis.

The zinc contents of fragments of Escherichia coli glutamyl-tRNA synthetase, as well as the conservation of the CYC sequence only in zinc-containing glutamyl-tRNA synthetases, suggested that the 98CYCX24-CRHSHEHHADDEPC138 includes some or all residues involved in binding its zinc atom (Liu, J., Lin, S.-X., Blochet, J.-E., Pézolet, M., and Lapointe, J. (1993) Biochemistry 32, 11390-11396). Extended x-ray absorption fine structure (EXAFS) shows that this zinc atom has a four-coordinate non-planar coordination environment with 3 sulfur and 1 nitrogen atoms with bond lengths, respectively, 2.37 +/- 0.02 A and 2.01 +/- 0.02 A, presumably belonging to 3 cysteine residues and 1 histidine residue. Conservative replacement of each histidine and cysteine residue of the 98C-138C segment, respectively, with glutamine (Q) and serine (S), yields variants H129Q, H131Q, H132Q, and C138S (which sustain the growth at 42 degrees C of E. coli JP1449, whose glutamyl-tRNA synthetase is thermosensitive) and C98S, C100S, C125S, and H127Q (which do not). The amount of this enzyme in these mutants is at least 1 order of magnitude larger than that in a wild type strain; however, no glutamyl-tRNA synthetase activity is detectable in extracts of the variants C100S and C125S, whereas its specific activity in those of C98S and H127Q is about 10-fold lower than in cells overproducing the wild type enzyme or the variants H129Q, H131Q, H132Q, and C138S. These results indicate that the zinc atom present in E. coli glutamyl-tRNA synthetase is bound by the 2 evolutionarily conserved cysteines at positions 98 and 100, and by Cys125 and His127. Molecular modeling of the N-terminal half of this enzyme, using the known structure of E. coli glutaminyl-tRNA synthetase, supports this conclusion and suggests that the 98C-127H segment does not have the characteristics of the classical zinc fingers.

Absorptiometry, Photon↗
PubMed1995

Cytospins--an alternative method for fine-needle aspiration cytology of the breast: a study of 148 cases.

The aim of this study was to evaluate the cytospin technique as an alternative method to prepare fine-needle aspiration (FNA) specimens of the breast. To do so, the cytology of 148 breast FNAs that had been prepared by the cytospin technique and that had histologic correlation, was reviewed. All the cases that were diagnosed as malignant by cytology were proved malignant after surgical excision, and there were no false-positive results. All but two cases diagnosed as benign by cytology proved to be benign on excision. The two false-negative cases were missed due to sampling error. The cytological features seen on cytospins were similar to those seen on conventional direct smears. The major advantage of this method is that no aspirate is unsatisfactory due to unskilled direct smear technique. This, along with its good correlation with histology, proves that the cytospin method is an effective alternative to conventional direct smears for breast FNA.

Biopsy, Needle↗
PubMed1995

High resolution solid-state 29Si NMR spectroscopy of silicone gels used to fill breast prostheses.

We have used 29Si solid-state nuclear magnetic resonance (NMR) spectroscopy to study the chemical structure of the silicone gels in virgin and explanted breast prostheses. Despite evidences of alteration in the morphological appearance of the silicone gel inside the breast prosthesis, our results do not reveal changes in the chemical nature and structure of the silicone gels after implantation. In addition to the main 29Si resonance peak at -22.26 ppm that corresponds to the resonance frequency of the D repeat unit of the polysiloxane chains, the high sensitivity of our NMR technique allows the detection of very low concentrations of silicone compounds. Within our experimental detection limit of 0.2%, no signal between -90 ppm and -150 ppm are observed. This indicates that no silica products are present inside the gel of the prostheses. Furthermore, our 29Si NMR spectra indicate differences in the chemical compositions of the silicone gels from different manufacturers.

Breast Implants↗
PubMed1995

High resolution 1H nuclear magnetic resonance of a transmembrane peptide.

Although the strong 1H-1H dipolar interaction is known to result in severe homogeneous broadening of the 1H nuclear magnetic resonance (NMR) spectra of ordered systems, in the fluid phase of biological and model membranes the rapid, axially symmetric reorientation of the molecules about the local bilayer normal projects the dipolar interaction onto the motional symmetry axis. Because the linewidth then scales as (3 cos2 theta-1)/2, where theta is the angle between the local bilayer normal and the magnetic field, the dipolar broadening has been reduced to an "inhomogeneous" broadening by the rapid axial reorientation. It is then possible to obtain high resolution 1H-NMR spectra of membrane components by using magic angle spinning (MAS). Although the rapid axial reorientation effectively eliminates the homogeneous dipolar broadening, including that due to n = 0 rotational resonances, the linewidths observed in both lipids and peptides are dominated by low frequency motions. For small peptides the most likely slow motions are either a "wobble" or reorientation of the molecular diffusion axis relative to the local bilayer normal, or the reorientation of the local bilayer normal itself through surface undulations or lateral diffusion over the curved surface. These motions render the peptide 1H-NMR lines too broad to be observed at low spinning speeds. However, the linewidths due to these slow motions are very sensitive to spinning rate, so that at higher speeds the lines become readily visible. The synthetic amphiphilic peptide K2GL20K2A-amide (peptide-20) has been incorporated into bilayers of 1,2-di-d 27-myristoyl-sn-glycero-3-phosphocholine (DMPC-d54) and studied by high speed 1H-MAS-NMR. The linewidths observed for this transbilayer peptide, although too broad to be observable at spinning rates below -5 kHz, are reduced to 68 Hz at a spinning speed of 14 kHz (at 500C). Further improvements in spinning speed and modifications in sample composition designed to reduce the effectiveness of the slow motions responsible for the linewidth should result in significant further reduction in peptide linewidths. With this technique, there is now the potential for the use of 1H-MAS-NMR for the study of conformation, folding, and dynamics of small membrane peptides and protein fragments.

Anisotropy↗
PubMed1995

High-speed magic angle spinning solid-state 1H nuclear magnetic resonance study of the conformation of gramicidin A in lipid bilayers.

One- and two-dimensional solid-state 1H nuclear magnetic resonance spectra of gramicidin A incorporated in a dimyristoylphosphatidylcholine membrane have been obtained with use of high-speed magic angle spinning. By rotating the sample at 13 kHz, it is possible to observe signals in the 1H spectra between 6.0 and 9.0 ppm attributable to the aromatic protons of the tryptophan residues and the formyl group proton of gramicidin A. Two-dimensional solid-state COSY spectra provided information for the peak assignments. Moreover, changes in the 1H spectra have been observed as a function of the co-solubilization solvent initially used to prepare the samples and therefore as a function of the conformation adopted by gramicidin A. Three organic solvents have been used: trifluoroethanol, a mixture of methanol/chloroform (1:1 v/v), and ethanol. The conformational interconversion of gramicidin A from the double helix conformation to the channel structure for the sample prepared from ethanol was confirmed by following the time evolution of the proton spectra.

Biophysical Phenomena↗
PubMed1995

New approach to study fast and slow motions in lipid bilayers: application to dimyristoylphosphatidylcholine-cholesterol interactions.

Natural abundance 13C solid-state nuclear magnetic resonance spectroscopy was used to investigate the effect of the incorporation of cholesterol on the dynamics of dimyristoylphosphatidylcholine (DMPC) bilayers in the liquid-crystalline phase. In particular, the use of a combination of the cross-polarization and magic angle spinning techniques allows one to obtain very high resolution spectra from which can be distinguished several resonances attributed to the polar head group, the glycerol backbone, and the acyl chains of the lipid molecule. To examine both the fast and slow motions of the lipid bilayers, 1H spin-lattice relaxation times as well as proton and carbon spin-lattice relaxation times in the rotating frame were measured for each resolved resonance of DMPC. The use of the newly developed ramped-amplitude cross-polarization technique results in a significant increase in the stability of the cross-polarization conditions, especially for molecular groups undergoing rapid motions. The combination of T1 and T1 rho measurements indicates that the presence of cholesterol significantly decreases the rate and/or amplitude of both the high and low frequency motions in the DMPC bilayers. This effect is particularly important for the lipid acyl chains and the glycerol backbone region.

Carbon Isotopes↗
PubMed1995

Structural model for the beta-amyloid fibril based on interstrand alignment of an antiparallel-sheet comprising a C-terminal peptide.

Amyloids are a class of noncrystalline, yet ordered, protein aggregates. A new approach was used to provide the initial structural data on an amyloid fibril--comprising a peptide (beta 34-42) from the C-terminus of the beta-amyloid protein--based on measurement of intramolecular 13C-13C distances and 13C chemical shifts by solid-state 13C NMR and individual amide absorption frequencies by isotope-edited infrared spectroscopy. Intermolecular orientation and alignment within the amyloid sheet was determined by fitting models to observed intermolecular 13C-13C couplings. Although the structural model we present is defined to relatively low resolution, it nevertheless shows a pleated antiparallel beta-sheet characterized by a specific intermolecular alignment.

Alzheimer Disease↗
PubMed1994

Diagnosis of lymphoma in a continuous ambulatory peritoneal dialysis patient by peritoneal fluid cytology.

A 72-year-old woman with diabetic nephropathy receiving continuous ambulatory peritoneal dialysis for 1 year presented with recurrent episodes of sterile cloudy dialysate. Abdominal ultrasound and computed tomography demonstrated retroperitoneal masses. Cytology of the dialysis fluid revealed large atypical lymphocytes with light chain restriction, strongly suggestive of lymphoma. Fine-needle aspiration of the retroperitoneal masses showed cells with identical cytologic and immunocytochemical staining characteristics. This is the first report of de novo lymphoma diagnosed in a continuous ambulatory peritoneal dialysis patient by cytologic analysis of the dialysis effluent.

Aged↗
PubMed1994

Estrogen receptor immunostaining patterns imaged in breast cancer fine needle aspirates.

Fine needle aspirates (FNA) after estrogen receptor (peroxidase-antiperoxidase) immunostaining were imaged using a SAMBA system. Integrated optical density (IOD) and mean optical density (MOD) was measured in individual nuclei. Receptogram R Analytic software on a remote VAX computer was used to generate log-log scatter, contour and three-dimensional perspective plots of bivariate MOD vs. IOD relationships and for count-dependent Gaussian smoothing of the univariate log histograms. The findings revealed four types of staining patterns among otherwise estrogen receptor immunostaining-positive patients: (I) a discrete, homogeneous subpopulation with unimodal MOD and IOD distributions; (II) coexistent subpopulations of ER+ and ER- cells, revealed by bivariate MOD and IOD distributions; (III) multiple, discrete subpopulations of ER+ cells, revealed in perspective plots of MOD vs. IOD vs. scatter density; and (IV) highly skewed distributions forming a continuum over a broad MOD and IOD range with or without an ER-negative subpopulation. FNA ER-ICA-positive specimens were indistinguishable based upon average nuclear MOD (AV-MOD) or AV-MOD x (% ER-positive cells). Previous evaluation of such patterns in tissue sections revealed failure of tamoxifen response in types II and IV. Staining mosaicism (IV) may correspond to a failure of receptor modulation within defined limits when ER is rendered nonfunctional due to various structural modifications of receptor domains--events that would not affect immunostaining. Failure in type II is ascribed to ascendancy of estrogen-independent ER-negative subpopulations.

Biopsy, Needle↗