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Biomedical subjects

L M Cruz Orive

Publications and source records attributed to L M Cruz Orive.

5 recordsLinked to original sources
PubMed1980

On the estimation of particle number.

Two methods are proposed for estimating the number of separated particles within a solid structure per unit volume of structure, Nv. Apart from being arranged with independence of any size parameter, no special assumptions upon the size, shape and orientation of the particles are made. The first method is based on the identity NV = (NA)u . microunits-1, where (NA)u is the mean number of particle sections per unit area of a plane probe Tu which is uniform random within the structure and perpendicular to a given direction u, whereas microunits is the mean particle caliper length along u. The second method uses NV - AA . v-1, where AA is the mean areal fraction of the particles per unit area of section, whereas v is the mean particle volume. The estimation of (NA)u, microunits and v requires the examination of parallel serial sections above and below Tu. Particle model reconstructions are not needed, however. Previous approaches to the problem are discussed.

Anatomy↗
PubMed1979

A rapid method for estimating volume ratios.

A rapid stereological method is proposed for estimating the volume ratio V(K2)/V(K1) of two bodies K1, K2 such that K2 is embedded in K1. If K1, K2 fit approximately into a 'star specimen' model, then a single section, taken at a certain level through K1, provides a rather accurate estimate of V(K2,/V(K1). For a population of moderately similar star specimens, a constant sectioning level can be estimated from a sample using a least squares criterion. A pilot experiment involving mouse lymph nodes, aimed at estimating the mean and the variance of the individual fractions V (paracortex)/V(node), indicates a fair robustness against deviations from the model.

Anatomy↗
PubMed1976

Correction of stereological parameters from biased samples on nucleated particle phases. I. Nuclear volume fraction.

Stereologists are aware that the experimental evaluation of component volume fractions and surface-to-volume ratios are subject to systematic errors whenever the requirements for cell identification impose the necessity for component-biased sectioning. Mathematical corrections of biased volume proportion data have recently been published; these corrections assume that the components under analysis are spherical, and that the nucleated particle phase is monodispersed. In this report, general methods for obtaining corrections of biased nuclear volume fraction data are set out for polydispersed phases of nucleated particles, in terms of the relevant shapes and joint size distribution of nucleus and cell; the scope and limitations of these methods are thereby discussed. Explicit corrections of an immediate applicability are obtained, together with their standard errors, for monodispersed phases where nucleus and cell are two dissimilar biaxial ellipsoids (spheroids). When nucleus and cell are two concentric and similar convex bodies of a certain class--to which triaxial ellipsoids belong--the corrections are shown to be very simple. The corrections for the spheroid-spheroid systems are easily accessible with the aid of a small programmable calculator, whereas those for the sphere-spheroid models are directly obtainable from two nomograms.

Cell Nucleus↗
PubMed1976

Correction of stereological parameters from biased samples on nucleated particle phases. II. Specific surface area.

General formulations for correcting component-biased S/V estimates on polydispersed phases of nucleated particles are set out. Direct application of these corrections to monodispersed phases where nucleus and cell are spheroids, yield explicit corrections. As a rule, the corrected specific surface area of the containing bodies equals the product of the nuclear-biased estimate times a correction coefficient, which is bigger than one, and depends upon the shape of the components and the relative volume of nucleus-in-cell. Reference curves which allow a rapid obtention of the correction factor, are provided. Simple formulae for correcting biased surface density and surface-to-volume ratio estimates other than the specific surface area, are also given, together with the standard errors of the corrected parameters.

Anterior Horn Cells↗