PubMed Health⌕ Search

Biomedical subjects

M Auger

Publications and source records attributed to M Auger.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1993

Solid-state 13C NMR study of a transglutaminase-inhibitor adduct.

We have used solid-state 13C NMR to study the structure of the adduct resulting from the inactivation of the enzyme transglutaminase by 3-halo-4,5-dihydroisoxazoles. These inhibitors were conceived on the assumption that they would inhibit transglutaminase by attack of an enzyme active site cysteine thiol on the imine carbon of the dihydroisoxazole ring. The tetrahedral intermediate formed could then break down with the loss of the halide group and the subsequent formation of a stable imino thioether adduct. We have compared the 13C CPMAS spectra of the chloro-, bromo-, and (ethylthio)dihydroisozazole inhibitors, and the results indicate that the chemical shift of the C-3 carbon is sensitive to the nature of the heteroatom. Subtraction of the natural-abundance 13C solid-state NMR spectrum of the enzyme from that of the enzyme inactivated by C-3-labeled chlorodihydroisoxazole reveals a broad peak at 156 ppm. The chemical shift of this peak is very close to that observed for a model 3-ethylthio compound and suggests the formation of a stable imino thioether enzyme adduct. Similar results were obtained for lyophilized enzyme adducts and for frozen solutions of the enzyme adduct in the absence and presence of Ca2+. We have also compared these results with those obtained by solution NMR on an aqueous solution of the enzyme-inhibitor complex. The 13C-labeled C-3 resonance was not observed in this case.

Animals↗
PubMed1993

Fine-needle aspiration cytology of sarcomatoid renal cell carcinoma: a morphologic and immunocytochemical study of 15 cases.

Sarcomatoid renal cell carcinoma (SRCC), which accounts for 5% of all renal cell carcinomas (RCC), has a worse prognosis than conventional nonsarcomatoid RCC, making accurate diagnosis important. This study reports on the morphologic and immunocytochemical features of 15 cases of SRCC (9 primary tumors and 6 metastases) diagnosed by fine-needle aspiration (FNA) biopsy. All but three cases showed a dimorphic cell population consisting of varying proportions of a high-grade epithelial component, either clear or granular-cell type and a spindle cell (sarcomatoid) component, of either fibrosarcomatous, malignant fibrous histiocytoma (MFH), or unclassified types. The sarcomatoid component in the biphasic and monophasic tumors stained positively for cytokeratin in 12 of 14 (85%) cases, for vimentin in 10 of 11 (91%) cases, and for muscle-specific action in 4 of 11 (36%) cases. Of note, the three cases that demonstrated a purely sarcomatoid morphology stained positively for cytokeratin. Unlike in studies performed on surgically resected specimens, neither the proportion of the sarcomatoid component nor the presence of necrosis had prognostic significance, the discrepancy most likely being related to the sampling. We conclude that SRCC, both primary and metastatic, can be accurately diagnosed by FNA when cytologic features are evaluated in conjunction with immunocytochemical findings.

Adult↗
PubMed1993

Solvent history dependence of gramicidin-lipid interactions: a Raman and infrared spectroscopic study.

We have investigated the interactions between gramicidin and a model membrane composed of one phospholipid, dimyristoylphosphatidylcholine, as a function of the cosolubilization solvent and incubation time used in the sample preparation. Three organic solvents have been used; trifluoroethanol, a mixture of methanol/chloroform (1:1 v/v), and ethanol. Using Fourier transform infrared spectroscopy, we have demonstrated that the conformation adopted by gramicidin in the membrane is dependent upon the cosolubilization solvent used, and, only with trifluoroethanol, it is possible to incorporate gramicidin entirely as a beta 6.3-helix. Moreover, Raman spectroscopy results indicate that the orientation of the tryptophan side chains in gramicidin and their interaction with the hydrocarbon chains and the carbonyl groups of the lipids are also dependent on the cosolubilization solvent. On the other hand, the effect of the incorporation of gramicidin on the thermotropism of the lipid bilayer was found to be dependent upon the conformation of gramicidin in the lipid bilayers.

Dimyristoylphosphatidylcholine↗
PubMed1993

Histopathologic classification of cervical carcinomas and recognition of mucin-secreting squamous carcinomas.

Recently, cervical mucin-secreting squamous carcinomas have been reported to be more common in younger women than in older women, leading some to conclude that any histologic classification of cervical carcinoma should include a specific category of this tumor type. One hundred and ninety-six invasive cervical carcinomas were classified using two histologic classification systems--the World Health Organization (WHO) and a system that recognized mucin-secreting squamous carcinomas (Fox). Analyses were performed to determine whether there was an association between age and glandular tumor types in either system. In the WHO System, 72% were classified as squamous carcinoma, 22% adenocarcinoma, and 6% adenosquamous. In the Fox System, 54% were squamous carcinoma, 22% adenocarcinoma, 4% adenosquamous, and 20% squamous carcinoma with mucin secretion. Specimen type did not significantly affect the classification of a carcinoma. No association was established between age and a diagnosis of adeno- and adenosquamous carcinomas in the WHO System, or age and adeno-, adenosquamous, and mucin-secreting squamous carcinomas in the Fox System. We conclude that use of the WHO Classification System does not obscure significant epidemiologic trends that are evident in a classification system that identifies mucin-secreting squamous carcinomas.

Adenocarcinoma↗
PubMed1993

Quantitation of immunocytochemical estrogen and progesterone receptor content in fine needle aspirates of breast carcinoma using the SAMBA 4000 image analysis system.

Evaluation of estrogen receptors (ER) and progesterone receptors (PR) in breast carcinoma using ER and PR immunocytochemical assays (ER-ICA and PR-ICA) has traditionally been semiquantitative at best. We investigated the use of the SAMBA 4000 image analysis system for quantitation of immunocytochemical ER content in 23 cases and PR content in 20 cases of breast carcinoma after obtaining cytology specimens by fine needle aspiration (FNA). We compared the quantitative assessment obtained by image analysis, the quick score (QS), to the biochemical assay as well as to the ER-ICA and PR-ICA semiquantitative visual histochemical score (H-score). Using Pearson's linear correlation coefficient, we demonstrated that for both ER and PR, the QS obtained by the "area" or "nuclear" programs correlated significantly with the H-scores. However, while the QS obtained on the area program for both ER and PR correlated significantly with the biochemical assay, the QS obtained on the nuclear program did not. The discrepancy might reflect the smaller number of cells evaluated with the nuclear program as compared to the area one. These results show that the SAMBA 4000 system provides an objective means of quantitating ER and PR content by immunocytochemical methods.

Biopsy, Needle↗
PubMed1992

Expression and amplification of neu oncogene in pleomorphic adenomas of salivary gland.

Amplification of the neu oncogene and overexpression of its product was found to be a potential marker for aggressive biological behavior in breast cancer. However, the expression of the neu oncoprotein in normal breast ducts and myoepithelial cells has also been demonstrated. Hence, we examined normal salivary gland tissue and 15 cases of pleomorphic adenoma for the expression of the neu oncoprotein by immunohistochemistry using two polyclonal antibodies and 12 cases for the amplification of the neu oncogene using slot blot hybridization. Immunohistochemistry in the normal salivary gland revealed positive staining of all ductal cells. In the pleomorphic adenomas all cellular elements stained to a variable degree. The positive staining was seen in the ductal cells, in the solid sheets, and in chondroid, myxoid, and metaplastic foci. The normal salivary gland and 11 of 12 cases of pleomorphic adenoma showed no increase in copy number of the neu oncogene, whereas one case showed threefold amplification. These results indicate that the neu oncoprotein is expressed but the neu copy number is not increased in normal salivary gland epithelium and in most pleomorphic adenomas. The threefold amplification of the gene in one case may indicate an aggressive biological behavior.

Adenoma, Pleomorphic↗
PubMed1991

An unusual peptide conformation may precipitate amyloid formation in Alzheimer's disease: application of solid-state NMR to the determination of protein secondary structure.

The formation of insoluble proteinaceous deposits is characteristic of many diseases which are collectively known as amyloidosis. There is very little molecular-level structural information available regarding the amyloid deposits due to the fact that the constituent proteins are insoluble and noncrystalline. Therefore, traditional protein structure determination methods such as solution NMR and X-ray crystallography are not applicable. We report herein the application of the solid-state NMR technique rotational resonance (R2) to the accurate measurement of carbon-to-carbon distances in the amyloid formed from a synthetic fragment (H2N-LeuMetValGlyGlyValValIleAla-CO2H) of the amyloid-forming protein of Alzheimer's disease (AD). This sequence has been implicated in the initiation of amyloid formation. Two distances measured by R2 indicate that an unusual structure, probably involving a cis amide bond, is present in the aggregated peptide amyloid. This structure is incompatible with the accepted models of fibril structure. A relationship between this structure and the stability of the amyloid is proposed.

Alzheimer Disease↗
PubMed1991

Beta 1-6 branched oligosaccharides as a marker of tumor progression in human breast and colon neoplasia.

Malignant transformation of murine and human cells is commonly associated with increased--GlcNAc beta 1-6Man alpha 1-6Man beta--branching in asparagine-linked oligosaccharides. Somatic mutations and drugs which block expression of the beta 1-6 branched oligosaccharides are potent inhibitors of tumor cell invasion and metastasis in animal models. This suggests that the oligosaccharides are required for metastasis to occur and therefore their increased presence in primary tumors may be diagnostic of metastatic disease. Although antibodies to the beta 1-6 branched portion of the oligosaccharides are not available, a plant lectin leukoagglutinin (L-PHA) has been shown to bind specifically to this structure. L-PHA lectin histochemistry was performed on paraffin sections of human breast and colon tissues. All breast carcinomas and epithelial hyperplasia with atypia showed significantly increased L-PHA staining compared to fibroadenomas and hyperplasia without atypia. In histological sections of colon, adenomas showed a small but significant increase in L-PHA staining compared to normal colonic epithelium, while carcinomas showed greatly increased reactivity. In addition, Dukes stage C tumors showed higher levels of L-PHA staining than stage A tumors. These results demonstrate that L-PHA-reactive beta 1-6 branched N-linked oligosaccharides are consistently increased in neoplasias of human breast and colon and that the level of L-PHA staining correlates with the pathological staging of the diseases.

Adenofibroma↗
PubMed1991

Slow motions in lipid bilayers. Direct detection by two-dimensional solid-state deuterium nuclear magnetic resonance.

Two-dimensional solid-state 2H NMR spectroscopy of specifically deuteriated lipids is used to detect and to characterize the rate and mode of slow motions in two lipid bilayer systems. Lateral diffusion of lipid molecules over the curved surface of dipalmitoylphosphatidylcholine liposomes can be detected by two-dimensional exchange 2H NMR and it is shown that molecular orientational exchange is complete on the timescale of 100 ms. In contrast, it is shown that for the glycolipid 1,2-di-O-tetradecyl-3-O-Beta-D-glucopyranosyl)-sn-glycerol (beta-DTGL), there is no evidence of a corresponding orientational exchange in the liquid-crystalline phase suggesting that this lipid forms relatively flat bilayers. In the gel phase of hydrated multibilayers of beta-DTGL, a slow (10(3) s(-1)) whole molecule axial motion is demonstrated at 40 degrees C. Comparison of the experimental and simulated 2D-NMR ridge patterns suggests that large angle jumps about the long molecular axis, rather than small step Brownian diffusion, can best account for the 2D-exchange spectra of beta-DTGL in the gel phase. The significance of this technique for the study of dynamics in other biological systems is discussed.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1991

Molecular details of anesthetic-lipid interaction.

By means of isotopic labeling with deuterium (2H) and observation by nuclear magnetic resonance (NMR), it has been possible to measure the conformational ordering and dynamics of lipids and anesthetics in membranes. The local anesthetic tetracaine causes disordering in the acyl chains of the lipids, very little effect near the glyceryl residue, and minor ordering effects in the charged head group. The anesthetic itself is well ordered within the lipid matrix. The magnitudes of these effects depend upon the nature of the lipid, and upon whether or not the anesthetic is charged. A model can be constructed for the location of the anesthetic within the lipid bilayers. Confirmation of the model comes from Fourier transform infrared spectroscopy (FTIR), which also shows directly the pressure-driven exclusion of local anesthetic from lipid, and the augmentation of this effect by the presence of cholesterol. Future studies by solid-state NMR of protein, and neutron diffraction of specifically deuterated components of anesthetic-nerve systems, should reveal even more precise details of the molecular events involved in anesthesia.

Anesthesia↗
PubMed1991

Smith-Magenis syndrome: a new contiguous gene syndrome. Report of three new cases.

Interstitial deletion of the short arm of chromosome 17 was detected in three patients. They all had a similar phenotype with mental retardation, behavioural problems, facial dysmorphism, brachycephaly, a broad face with a flat midface, and short and broad hands. All three cases were ascertained over a six month period by two neuropaediatricians aware of this specific anomaly, which suggests that this microdeletion is not particularly rare. Comparison of the clinical and cytogenetic findings in a total of 24 patients allows a new contiguous gene syndrome to be defined that only high resolution analysis can detect. In two cases, molecular analysis confirmed the cytogenetic results. The Charcot-Marie-Tooth type Ia gene has recently been localised to the 17p11.2 sub-band.

Abnormalities, Multiple↗
PubMed1990

Glycerolipids: common features of molecular motion in bilayers.

In the present study, analysis of 2H NMR line-shape and spin-lattice relaxation behavior has been used to investigate the dynamics of several glycolipid and phospholipid bilayers. The gel-phase spectra of these lipids labeled at the C3 position of the glycerol backbone are broad (approximately 90 kHz) and characteristic of fast-limit axially asymmetric motion. Moreover, anisotropic spin-lattice relaxation is observed in all of these systems. The line-shape and relaxation features of the lipids in the gel phase were best simulated by using a fast-limit three-site jump model, with relative site populations of 0.46, 0.34, and 0.20. This motion is associated with an internal jump about the C2-C3 bond of the glycerol backbone. A second motion, rotation about the long axis of the molecule, is needed to account for the observed temperature dependence of the quadrupolar echo amplitude and the spectral line shape above and below the gel to liquid-crystalline phase transition temperature. On the other hand, the gel-phase spectra of phospholipids labeled at the C2 position of the glycerol backbone are also characterized by a fast internal motion, which is simulated by a two-site librational jump. The results indicate that the glycerol backbone dynamics of the glycolipid and phospholipid systems investigated in this study can be described in terms of common fast internal motions and a slower whole molecule axial motion. These results are compared with previous dynamic studies of similar systems.

Computer Simulation↗
PubMed1990

High-pressure infrared study of phosphatidylserine bilayers and their interactions with the local anesthetic tetracaine.

High-pressure Fourier-transform infrared (FT-IR) spectroscopy was used to study the barotropic behavior of phosphatidylserine bilayers and their interactions with the local anesthetic tetracaine. The model membrane systems studied were multilamellar aqueous dispersions of 1,2-dimyristoyl-sn-glycero-3-phospho-L-serine (DMPS) and 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) in the absence and the presence of tetracaine at pH 5.5 and 9.5. The infrared spectra were measured at 28 degrees C in a diamond anvil cell as a function of pressure up to 25 kbar. The results show that the barotropic behavior of the negatively charged phosphatidylserine bilayers is very similar to that observed for zwitterionic phospholipids, such as phosphatidylcholine and phosphatidylethanolamine, with corresponding acyl chains. The results also indicate that the local anesthetic partitions into phosphatidylserine bilayers in an environment close to the membrane-water interface and interacts electrostatically with the lipid head group. Application of high hydrostatic pressure on the lipid-anesthetic systems results in the pressure-induced expulsion of the anesthetic from a membrane to an aqueous environment. The pressures required for expulsion of anesthetic from bilayers are much higher for the unsaturated lipid (DOPS) than for the saturated lipid (DMPS) (approximately 6 kbar vs approximately 2 kbar, respectively). Whereas incorporation of the anesthetic into DOPS bilayers does not affect significantly the structural and dynamic properties of the disordered acyl chains in the liquid-crystalline phase, it orders the DMPS acyl chains in the gel phase.

Lipid Bilayers↗
PubMed1990

Detection of metastatic vulvar and cervical squamous carcinoma in regional lymph nodes by use of a polyclonal keratin antibody.

A polyclonal keratin antibody (pK), a marker for epithelial cells, was used to evaluate lymph nodes (LNs) from patients with invasive squamous carcinomas of the cervix (CxCa) or vulva (VCa) to determine whether this technique could increase the detection of metastases (mets) over that obtained by light microscopy using a routine hematoxylin and eosin (H&E)-stained slide. The LN status of 15 cases of stage 1B CxCa and 14 cases of VCa was determined using a routine H&E slide. Subsequently, all LNs were resectioned and examined using a pK immunoperoxidase stain. In 329 lymph nodes from 14 cases of CxCa and 9 cases of VCa originally classified as LN-negative, only a single met was detected by the pK technique. In five cases of VCa and one case of CxCa (121 LNs), with LN mets or LN tumor emboli on the original H&E, three additional microscopic foci of mets were detected by pK. Of the four foci of mets discovered by pK, one was visible in retrospect on the original H&E section, and all four were easily identified on examination of a serial H&E section adjacent to the pK section. These results suggest that pK stains are unlikely to significantly increase our sensitivity in detecting mets in CxCa and VCa, beyond merely further sectioning and H&E staining of nodes.

Biomarkers, Tumor↗
PubMed1990

Diagnosis of a peripheral neuroectodermal tumour by fine needle aspiration.

One case of malignant peripheral neuroectodermal tumour successfully diagnosed by cytology is presented. Although a Papanicolaou stained smear could not lead to a diagnosis more specific than a malignant small cell tumour, ancillary analytic methods performed on the cytologic material including immunocytochemistry and electron microscopy yielded the correct diagnosis of peripheral neuroectodermal tumour. This case demonstrates that a precise categorization of small round cell tumours may be achieved by cytology as long as some material is kept for immunocytochemical and ultrastructural studies.

Adolescent↗
PubMed1989

Interactions of the local anesthetic tetracaine with glyceroglycolipid bilayers: a 2H-NMR study.

We have examined the effects of the local anesthetic tetracaine on the orientational and dynamic properties of glycolipid model membranes. We elected to study the interactions of tetracaine with the pure glycolipid 1,2-di-O-tetradecyl-3-O-(beta-D-glucopyranosyl)-sn-glycerol (beta-DTGL) and a mixture of beta-DTGL (20 mol%) in dimyristoylphosphatidylcholine (DMPC) by deuterium NMR (2H-NMR) spectroscopy. 2H-NMR spectra of beta-DTGL have been measured as a function of temperature in the presence of both the charged (pH 5.5) and uncharged forms (pH 9.5) of tetracaine. The results indicate that the anesthetic induces the formation of non-lamellar phases. Specifically, the incorporation of uncharged tetracaine results in the formation of a hexagonal phase which is stable from 52 to 60 degrees C. At lower pH, the spectrum at 52 degrees C is very reminescent of that of the beta-glucolipid alone in a bilayer environment, while as the temperature is elevated to 60 degrees C, a transition from a spectrum indicative of axial symmetry to one due to nearly isotropic motion or symmetry occurs, which may result from the formation of a cubic phase. Although it leads to an alteration in the phase behavior, the presence of tetracaine does not induce large changes in the headgroup orientation of beta-DTGL. In contrast to the pure glycolipid situation, the interaction of tetracaine with beta-DTGL (20 mol%) in DMPC does not trigger the formation of non-lamellar phases, but leads to a slight reduction in molecular ordering. The presence of the charged form of the local anesthetic near the aqueous interface of the bilayer appears to induce a small change in the conformation about the C2-C3 bond of the glycerol backbone of beta-DTGL in the mixed lipid system. Thus, the major influence of the local anesthetic on glycolipids is a change in the stability of the lamellar phase, facilitating conversion to phases with hexagonal or isotropic environments for the lipid molecules.

Chemical Phenomena↗