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D M Brunette

Publications and source records attributed to D M Brunette.

79 records · Page 5Linked to original sources
PubMed1975

A reliable method of quantifying G-band position in chromosomes.

The locations of chromosomal bands in the muntajac (Muntiacus muntjak, Zimmerman) are shown to be constant, that is the bands occupy the same relative position regardless of the state of contraction of the chormosome. Each band can thus be assigned a precise location. Different banding techniques produce bands at identical locations and thus precisely similar patterns, with one notable exception in which certain bands disappear. It it proposed that this more exact procedure be used to identify chromosomal bands, especially in cases of chromosomal rearrangement. It may be of particular use in computer analyses of karyotypes.

Animals↗
PubMed1975

The interactions of benzo(a)pyrene with cell membranes: uptake into Chinese hamster ovary (CHO) cells and fluorescence studies with isolated membranes.

The interactions of benzo(a)pyrene (B(a)P) with the cell surface membrane were studied by measuring B(a)P uptake into intact mammalian cells and by determining B(a)P fluorescence in the presence of isolated cell surface membranes. It was found that 0.19 mu-g B(a)P were taken up by 10-6 Chinese hamster ovary (CHO) cells after 30 min exposure to a solution containing 0.59 mu-g/ml. Culture conditions were found to markedly alter B(a)P uptake. Low cell culture densities resulted in a four-fold increase in rate of B(a)P uptake per cell relative to confluent monolayer cultures. The uptake rate of B(a)P was reduced in the presence of bovine serum (BS) and, under some conditions, perylene. This information should be considered in the design of experiments on the biological effects of B(a)P. Another aspect of B(a)P membrane interaction was that the binding of B(a)P to cell surface membranes could be measured by fluorescence. The additional B(a)P fluorescence, found in the presence of cell surface membranes, was sufficiently large that the methods of data treatment used in the study of fluorescent probe-membrane interactions could be applied to get quantitative information on B(a)P-membrane interactions. It was found that 0.6 x 10-8 moles B(a)P were bound per mg membrane protein and that the apparent statistical dissociation constant for the complex was 3.8 x 10-7 M. The data suggest that the mechanism of uptake of B(a)P is probably passive diffusion.

Anilino Naphthalenesulfonates↗
PubMedDate not supplied

Response of single, pairs, and clusters of epithelial cells to substratum topography.

Cells cultured on grooved substrata change their shape, orientation, and direction of locomotion in response to substratum topography, a phenomenon called contact or topographic guidance. Porcine epithelial cells (E-cells) spread on micromachined grooved or smooth control surfaces were examined by epifluorescence and confocal microscopy to determine area, cell shape, and orientation in conjunction with distributions and orientations of actin filaments and microtubules. Single cells, cells within a pair or cluster, and pairs or clusters considered as a unit were compared. As expected, cell contact increased cell spreading, but surprisingly, increased cell contact influenced cell shape on smooth and grooved surfaces and increased alignment of cells spread on grooves. Both actin filaments and microtubules aligned initially and most consistently along the walls and ridge-groove edges. Single E-cells displayed the least variability of aligned cytoskeletal patterns. E-cells within clusters displayed the most variability as local topographic effects on the cytoskeleton could be overridden by adjacent cell contact. Overall, contact guidance of E-cells was neither synonymous with nor contingent upon an elliptical morphology oriented to the topography. E-cells also differed from fibroblasts in their response to cell contact and in their lack of a relationship between cell polarity and locomotion.

Actins↗
PubMedDate not supplied

Wavelength-dependent roughness: a quantitative approach to characterizing the topography of rough titanium surfaces.

Topographies of grit-blasted, etched, grit-blasted and etched, and microfabricated and etched surfaces of commercially pure titanium have been investigated. Such surface topographies vary across the scale range of interest for dental implants, extending from nanometers to millimeters. The complete characterization of topography requires the use of complementary methods. This study compared the topographic characterization methods of non-contact laser profilometry, interference microscopy, stereo-scanning electron microscopy (stereo-SEM), and atomic force microscopy. Non-contact laser profilometry was shown to be a useful method to characterize topographic features in the micron to millimeter range, whereas interference microscopy and stereo-SEM can be employed down to the submicron range. Stereo-SEM is particularly useful for quantifying topographies with complex, strongly corrugated ("sharp"), and high-aspect-ratio features and was shown to be complementary to non-contact laser profilometry and interference microscopy. Because of tip-related envelope problems, atomic force microscopy was not found to be suitable for the type of surfaces investigated in this study. Independent of the method used, the commonly used "integral" amplitude roughness parameters, such as Ra, Rq, or Rt, were often of limited value in the description of actual implant surfaces. The application of the wavelength-dependent roughness approach was shown to be an effective method for the description of surface topographies in the complete range of characteristic roughness and is also a useful means of examining the effects of surface treatment processes.

Analysis of Variance↗