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M Auger

Publications and source records attributed to M Auger.

At least 73 records · Page 4Linked to original sources
PubMed1989

Cystosarcoma phylloides of the breast and its mimics. An immunohistochemical and ultrastructural study.

Cystosarcoma phylloides of the breast is a tumor composed of breast ducts and a cellular stromal component that can be benign or malignant. The origin of the stromal cells is controversial. We undertook an immunohistochemical and ultrastructural study of 11 cases of cystosarcoma phylloides to assess the histogenesis of the stromal component. By light microscopy, 4 were diagnosed as benign, and 7 were diagnosed as malignant. Antibodies to vimentin, desmin, actin, high- and low-molecular-weight keratins, and S100 protein were used for immunohistochemical staining. In the 4 benign cases of cystosarcoma phylloides, the stromal cells stained positively only for vimentin. In the malignant tumors, the spindle cell component stained for vimentin in all the cases. In addition, the malignant stromal cells coexpressed desmin in two cases and keratin and S 100 protein in another case. By electron microscopy the stromal component in the benign case and in two of five malignant cases was composed of a mixture of fibroblasts and myofibroblasts. The entire neoplastic stroma in two other malignant cases showed features of smooth-muscle differentiation, whereas in another case all the stromal cells showed myoepithelial differentiation. Thus, in benign and malignant cystosarcoma phylloides, the stromal component consists of a mixture of fibroblasts and myofibroblasts. Leiomyosarcomas and myoepitheliomas can mimic malignant cystosarcoma phylloides, but immunohistochemistry and electron microscopy can differentiate these entities. This is important since their biologic behavior is different.

Adolescent↗
PubMed1989

Renal oncocytoma in pregnancy: a case report.

Oncocytoma is an uncommon renal tumour and this is the first report of such a tumour occurring in a pregnant woman. Optimal treatment is nephrectomy and the prognosis is usually good, though metastasis has been reported. It is unknown whether pregnancy alters tumour behaviour or the prognosis.

Adenoma↗
PubMed1988

Effects of the local anesthetic tetracaine on the structural and dynamic properties of lipids in model membranes: a high-pressure Fourier transform infrared study.

High-pressure Fourier transform infrared (FT-IR) spectroscopy was used to study the effects of a local anesthetic, tetracaine, on the structural and dynamic properties of lipids in model membranes. The model membrane systems studied were multilamellar aqueous dispersions of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-di-O-hexadecyl-sn-glycero-3-phosphocholine (DHPC) in the absence and presence of a physiological concentration of cholesterol (30 mol %). 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 indicate that the effects of tetracaine on the structure of pure DMPC bilayers in the gel state are dependent on the state of charge of the anesthetic. The uncharged tetracaine disorders the lipid acyl chains while the charged form induces the formation of an interdigitated gel phase. The presence of cholesterol in the latter system prevents the formation of the interdigitated phase, whereas in the former system it disorders the lipid acyl chains in the gel state. Moreover, it is shown that the addition of uncharged tetracaine to interdigitated DHPC bilayers does not alter the interdigitated state of the hydrocarbon chains.

Cholesterol↗
PubMed1988

Interactions of the local anesthetic tetracaine with membranes containing phosphatidylcholine and cholesterol: a 2H NMR study.

The interactions of the local anesthetic tetracaine with multilamellar dispersions of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cholesterol have been investigated by deuterium nuclear magnetic resonance of specifically deuteriated tetracaines, DMPC and cholesterol. Experiments were performed at pH 5.5, when the anesthetic is primarily charged, and at pH 9.5, when it is primarily uncharged. The partition coefficients of the anesthetic in the membrane have been measured at both pH values for phosphatidylcholine bilayers with and without cholesterol. The higher partition coefficients obtained at pH 9.5 reflect the hydrophobic interactions between the uncharged form of the anesthetic and the hydrocarbon region of the bilayer. The lower partition coefficients for the DMPC/cholesterol system at both pH values suggest that cholesterol, which increases the order of the lipid chains, decreases the solubility of tetracaine into the bilayer. For phosphatidylcholine bilayers, it has been proposed [Boulanger, Y., Schreier, S., & Smith, I. C. P. (1981) Biochemistry 20, 6824-6830] that the charged tetracaine at low pH is located mostly at the phospholipid headgroup level while the uncharged tetracaine intercalates more deeply into the bilayer. The present study suggests that the location of tetracaine in the cholesterol-containing system is different from that in pure phosphatidylcholine bilayers: the anesthetic sits higher in the membrane. An increase in temperature results in a deeper penetration of the anesthetic into the bilayer. Moreover, the incorporation of the anesthetic into DMPC bilayers with or without cholesterol results in a reduction of the lipid order parameters both in the plateau and in the tail regions of the acyl chains, this effect being greater with the charged form of the anesthetic.

Cholesterol↗
PubMed1988

Achondroplasia in sibs of normal parents.

A new case of recurrent achondroplasia in sibs of normal parents is reported. Two sisters and a half sister were affected. Various mechanisms can be postulated to account for unexpected recurrence of achondroplasia in the same sibship. Germinal mosaicism and unstable premutation are discussed here.

Achondroplasia↗
PubMed1987

Pressure-induced exclusion of a local anesthetic from model and nerve membranes.

Because it is well established that the anesthetic state can be reversed by pressure, a number of molecular theories that have been proposed for the mechanism of action of both local and general anesthetics can be tested by varying the pressure. Using Fourier transform infrared spectroscopy, we report here the first direct observation of the expulsion from lipid bilayers of a local anesthetic, tetracaine, by pressure. Moreover, we establish for the first time that this phenomenon is common to both model membranes and to myelinated and unmyelinated nerve membranes, vindicating the utility of model membrane systems. A distinctive feature of this behavior in model systems is that, in saturated phosphatidylcholines at high pH, expulsion only occurs in the presence of cholesterol, whose ordering effect on the acyl chains evidently assists pressure in squeezing the anesthetic out of the bilayer. This pressure-induced phenomenon may provide insight into the molecular mechanisms underlying the antagonistic effect of pressure against anesthesia.

Animals↗
PubMed1985

The use of danazol in the management of chronic immune thrombocytopenic purpura.

Danazol has recently been reported to be an effective mode of treatment for patients with refractory immune thrombocytopenic purpura. Following a 3 month trial of danazol, only one of 10 patients experienced a sustained increase in platelet counts and two other patients had a transient improvement. While the drug was well tolerated, it does not appear to be particularly helpful in the management of these patients.

Adult↗
PubMed1984

[Mental retardation linked to fragility of chromosome X: current knowledge].

The association of the fragile X chromosome with X-linked mental retardation is now well established. The main clinical features are mental retardation, typical facial dysmorphism and macroorchidism. Cytogenetically there is a fragile site in band Xq27-28 which can be demonstrated using specific techniques. The genetic studies are compatible with a X-linked dominant inheritance with an incomplete penetrance. A preliminary estimation of an overall frequency of 1: 2000 males for the fra(X)(q) condition is suggested.

Bromodeoxyuridine↗
PubMed1981

X-linked mental retardation with the fragile X. A study of 15 families.

The clinical and cytogenetic features of 15 families with mental retardation linked to the fragile site on the X chromosome are presented. The 15 propositi were all prepubertal, and one was a girl. Although the clinical picture varied in severity, it was sufficiently constant to suggest the diagnosis from the facial features and the encephalopathy with language retardation and disturbed behavior. Macroorchidism was not seen before puberty. The fragile X chromosome was found in seven of the nine mothers studied and in two mildly retarded sisters and has also been demonstrated in fibroblasts in eleven subjects with the abnormality.

Adolescent↗
PubMed1979

Properties of spermatozoa in relation to their elimination after vasectomy.

Sperm disposal and the formation of sperm granulomas are two related critical aspects of vasectomy which have been studied in man and several animal models. Since mammalian spermatozoa present a keratinoid quality, a comparison was made of the resistance of human and rat spermatozoa. When exposed to dithiothreitol and sodium dodecyl sulfate, human sperm decondense readily while rat sperm resist decondensation for long periods of time. A cooperative effect in the rate of decondensation was observed for human sperm but not for rat sperm. Oxidation of sulfhydryl groups renders human spermatozoa as resistant as rat spermatozoa, indicating that disulfide crosslinks are involved in this resistance. Human spermatozoa constitute a heterogeneous population with respect to sulfhydryl group content, suggesting variations in the state of maturation and/or elimination. The sulfhydryl group content of rat epididymal spermatozoa was similar from one cell to another, suggesting little sperm reabsorption in the epididymis. Human and rat spermatozoa differ in size, resistance to decondensing agents, cooperative effect during decondensation, and content and localization of sulfhydryl groups; these differences can explain why vasectomized rats invariably develop huge granulomas while this side effect is not severe in vasectomized men.

Animals↗
PubMedDate not supplied

Atypical squamous cells of undetermined significance. A cytohistologic study of 52 cases.

OBJECTIVE: To evaluate the significance of atypical squamous cells of undetermined significance (ASCUS) by correlating the histologic findings following a diagnosis of ASCUS on a cervical cytologic smear. STUDY DESIGN: Eighty-four smears that had been called ASCUS over a five-month period and that had corresponding histologic material were reviewed independently. Only 52 of the 84 cases on which a consensus was reached were retained for the current study. RESULTS: The breakdown of the follow-up histologic diagnoses was as follows: 28 cases (54%) were negative (without squamous intraepithelial lesions [SIL]); 22 cases (42%) showed SILs, of which 14 (27%) were low grade, 5 (10%) were high grade and 3 (5%) had SILs that could not be further classified because of fragmentation of the endocervical curettings. Finally, two cases (4%) proved to be invasive cervical carcinoma on histology despite smears that were satisfactory and not limited by the quantity or quality of material; in these the discrepancy was attributed to sampling error. CONCLUSION: Patients whose cervical cytologic smears fall into the category of ASCUS may, on follow-up, exhibit a wide spectrum of findings, ranging from no pathologic abnormality to frequent SIL and even to invasive carcinoma in rare instances. A diagnosis of ASCUS on smears warrants careful follow-up and investigation.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Cytopathology and ultrastructure of primary rhabdoid tumor of lung.

This case report presents the light microscopy, immunocytochemistry, and ultrastructure of the first unequivocal extrarenal rhabdoid tumor occurring in lung. Smears and cell blocks prepared from a fine-needle aspiration biopsy show the cytopathological features of this unusual neoplasm, in this case presenting in a 74-year-old male. Electron microscopy of the surgically resected circumscribed pulmonary mass assisted in establishing the diagnosis by demonstrating the considerable accumulation of cytoplasmic intermediate filaments that characterize cells in extrarenal rhabdoid tumor and account for the hyaline "inclusion" in this particular lesion.

Aged↗
PubMedDate not supplied

Metastatic intracranial chordoma in a child with massive pulmonary tumor emboli.

A 27-month-old boy of Hispanic background developed multiple cranial nerve palsies, difficulty swallowing, bloody nasal discharge, and irritability. Radiographic evaluations showed extensive destruction of the clivus by a large tumor that invaded the sphenoid bone, left cavernous sinus, ethmoid sinus, nasal cavity, and left orbit. Multiple pulmonary nodules were also noted. The bone marrow and spinal fluid showed no evident tumor cells. Transnasal biopsy revealed a chordoma. Treatment was initiated with a combination of ifosfamide, mesna, and etoposide along with radiation therapy to the cranial tumor. Shifting pulmonary densities were noted on serial films. Despite some clinical improvement, the child developed rapidly progressive hypoxemia 3 weeks after admission and died. Autopsy showed persistent viable tumor in the primary site and massive pulmonary arteriolar tumor emboli, infarcts, and widespread lung parenchymal metastases. No other sites of tumor involvement were discovered. This is the second child reported with intracranial chordoma, pulmonary metastases at diagnosis, and early death attributed to pulmonary tumor emboli.

Brain Neoplasms↗