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Biomedical subjects

M Cayer

Publications and source records attributed to M Cayer.

11 recordsLinked to original sources
PubMed2004

Novel p21-activated kinase-dependent protrusions characteristically formed at the edge of transformed cells.

During long-term culture, certain lines become neoplastic while accumulating changes in cell shape. Early and late cell populations have characteristic shape phenotypes that have been quantified by computerized assay. Phenotypes are determined from variables describing three-dimensional aspects of the subcellular distribution of mass. The features of cells can be recognized by use of latent factors, which are theoretical variables based on the covariance of the primary variables. Factor #7 represented a cell edge feature different from filopodia. We studied the morphological characteristics and morphogenesis of the feature. Brief exposure of cells from rat tracheal epithelium to phorbol 12-myristate 13-acetate (PMA) enhanced #7 values. The time to reach maximal #7 values was prolonged if PMA was administered with calcium ionophore or lysophosphatidic acid (LPA). Factor #7 was elevated during periods of ruffling suppression and stress fiber reorganization. Cells showing high #7 values were examined by scanning electron microscopy (SEM) and found to exhibit strap-shaped and cupola-shaped projections. Because RhoA regulates stress fiber formation, we sought to perturb #7 features by introducing dominant-acting negative and positive constructs of RhoA, RhoA-N19, and RhoA-V14. Neither affected #7 values. Although overexpression of the kinase inhibitory domain of p21-activated kinase 1 (PAK) had no effect on #7 values, they were affected by overexpression of a domain binding PAK-interacting guanine nucleotide exchange factor (PIX). Because a PAK-PIX complex is implicated in the remodeling of focal complexes (FCs) and recycling of PAK to the cytoplasm, the results implicate a component of FCs in the formation of #7 features. The data suggested that feature formation is driven by activated Cdc42-binding kinase (ACK) and Rac. Moreover, they suggested that the #7 protrusions are neurite-like structures and that their development involves FC regulation.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2000

Prolongation of brainstem auditory-evoked responses in autistic probands and their unaffected relatives.

BACKGROUND: Brain function, as indexed by brain electrical activity, is heritable in humans, and it may be impaired in autism. Autism also has strong genetic determinants, and like all major psychiatric disorders, its complex clinical phenotype renders genetic studies difficult. Innovative strategies focused on alternative biological phenotypes are needed. METHODS: The early brain auditory-evoked response was assessed in 73 autistic probands and 251 relatives who were compared with 521 normal controls. RESULTS: We first confirmed in the autistic probands the presence of a slowing in nerve conduction in the auditory system as expressed by the prolongation of early brain auditory-evoked response under the form of I-III interpeak latencies (IPLs). Furthermore, we observed the same I-III IPL prolongation in the unaffected first degree relatives of the autistic probands compared with controls. Despite clear evidence of a coaggregation of autism and I-III IPL prolongation in families, the IPLs did not seem to be the sole liability factor for autism as suggested by the observation of 52% of families in which the autistic proband and relatives showed normal IPLs. CONCLUSION: A prolongation of the early brain auditory-evoked response IPLs may be a marker for one of several deficits underlying autism and deserves further analysis as a potential alternative phenotype for the disorder.

Adult↗
PubMed1999

Evidence of linkage in subtypes of alcoholism.

We believed that subtyping alcoholism might be an efficient strategy for mapping susceptibility genes. Cluster analysis is one of the possible statistical techniques for such a purpose. We required that, ideally, the variables to be used in cluster analysis should be: 1) related to alcoholism, 2) related to the severity of alcoholism, and 3) familial, i.e., correlated within families. Only three variables met all three conditions. Those included age of onset of ALDX1, smoking, and TPQ-HA. A global score of symptoms of alcoholism was systematically introduced as one of the variables composing a subset for cluster analysis, although this score did not show any familial aggregation. Our strategy led to a strong evidence of linkage at D15S230 in only 20 families whose members are mainly characterized by heavy smoking.

Age of Onset↗
PubMed1989

[Care of persons with cognitive deficiencies].

Care of those with cognitive deficits. Even a decade ago, articles on aging and those with cognitive deficits attracted relatively little attention. Now, educators, health care professionals and researchers alike consider the aged and maintenance of their autonomy to be priorities. Yet in spite of the good intentions of these groups, there will be no significant changes in care of the elderly and those with cognitive deficits without the cooperation and commitment of health care administrators, say these authors. As such, they raise questions about the way health institutions and more precisely care services and units are administered. The article also examines how history affects the organization of care--in particular, daily care. It is written in administrative terminology.

Aged↗
PubMed1985

Two-dimensional impedance studies of BSA buoyant density separated human erythrocytes.

Combined DC (Coulter Volume) and radio frequency impedance studies were performed on human erythrocytes which had been separated by buoyant density in linear, neutral, isotonic bovine serum albumin gradients. The individual buoyant density fractions showed no reproducible shift in volume with buoyant density but did show a shift with opacity, radio frequency impedance divided by dc impedance. This new electronic parameter of opacity can be related to cell age, since both it and cell age are directly related to buoyant density. This increase in opacity with buoyant density is correlated with a change in shape.

Adult↗
PubMed1982

Immunochemical studies of infectious mononucleosis--X. Characterization of a glycoprotein from horse erythrocytes which reacts with Paul-Bunnell antibody.

A highly purified preparation of horse erythrocyte glycoprotein was prepared from an aqueous ethanolic extract of hemoglobin-free membranes. The subunit apparent mol. wt was 30,000. In aqueous solution the glycoprotein formed globular aggregates of 93 +/- 16 A diameter. The glycoprotein had a receptor for the Paul-Bunnell antibody of infectious mononucleosis which was associated with an O-glycosidically linked oligosaccharide and dependent on the presence of N-glycolylneuraminic acid. In addition the glycoprotein had a neuraminidase-sensitive receptor for human peripheral blood lymphocytes. Fifty per cent inhibition of the rosetting of sheep red cells by 4 x 10(5) lymphocytes was caused by 30 microgram of glycoprotein.

Amino Acids↗
PubMed1982

Immunochemical studies of infectious mononucleosis. VIII. A glycoprotein from sheep erythrocytes with sialic acid-dependent receptor properties.

A glycoprotein was solubilized from sheep erythrocyte membranes with hot aqueous ethanol. The glycoprotein was purified by phosphocellulose chromatography, ethanol precipitation, lipid solvent extraction, and DEAE chromatography. In water solution the glycoprotein existed as globular aggregates with a diameter of 7.1 +/- 2.2 nm. In the presence of sodium dodecyl sulfate, 80% of the material exhibited a subunit m.w.app of 27,000. Approximately 10% of the material had a m.w.app of only 9000 and another 10% had a m.w.app of 35,000. All three fractions were reactive with Paul-Bunnell heterophile antibody from the sera of patients with infectious mononucleosis and with Limulus polyphemus lectin. These activities were destroyed by neuraminidase treatment. Complete inhibition of the rosetting of sheep red blood cells by 4 X 10(5) human peripheral blood lymphocytes was seen at 100 to 200 micrograms glycoprotein/ml. Neuraminidase-treated glycoprotein was not inhibitory. Pronase-derived sialoglycopeptide was inhibitory. Most likely, the receptor for lymphocytes resides in the carbohydrate portion of the glycoprotein. By using 125I-glycoprotein, binding studies were carried out that yielded an estimate of approximately 2 X 10(5) binding sites for sheep erythrocyte glycoprotein per lymphocyte. Purified glycoprotein contained 44.4% amino acid. Carbohydrate components and their molar ratios were sialic acid (1.0): galactose (1.0):N-acetylglucosamine (1.3): N-acetylgalactosamine (1.2).

Animals↗
PubMed1977

A procedure for dissociating Ayre scrape samples.

The dissociation of cervical cell suspensions after various chemical and enzymatic treatments was monitored by using the Centrifugal Cytology rotor to produce glutaraldehyde-fixed dispersions on conventional microscope slides and subsequent Pap staining. A special program was written in RPG II to record and analyze the results of the dissociation experiments in terms of white blood cells and the true cervical cells ("other cells"), and the degree of dissociation and recovery of both classes of cells. Since accurate differential counts on the untreated Ayre scrapes were difficult, the samples were syringed gently to break up the large or adventitious clumps. Cumulated results from control preparations indicate that the white blood cells and "other cells" are composed respectively of 92 and 63% single cells. The cells were further dissociated by: dissolving the cervical mucin sequentially with dithiothreitol and iodoacetic acid; depolymerizing the nucleohistone gel with ribonuclease; solubilizing the desmosomes with EDTA; removing the remaining cellular agglutinins with Varidase; and finally mechanical dispersion by hypertonic shock. The optimum procedure for dissociation involves the use of ribonuclease, dithiothreitol, iodoacetic acid EDTA, Varidase and sucrose shock. The white blood cells are now monodisperse and 81% of the "other cells" are found as single cells. If nuclear separation by two diameters is considered sufficient 98% of the "other cells" are single. The slide preparations are now sufficiently good that a scanning system is feasible.

Autoanalysis↗