Intestinal Absorptive Surface in Mammals of Different Sizes

ISBN-13: 9783540629863 / Angielski / Miękka / 1997 / 90 str.

Robert L. Snipes

Opis

1. 1 Scientific Aims In recent years, there has been a definite trend away from the casuistic scientific thinking which has dominated the scientific world, at least in the field of medicobi- ological research. Now, in the last decade of this century, scientists are returning to a conceptual way of thinking that characterized the beginning of this century, namely organismal thinking. The holistic concept is not a new one; it was rekindled by a small group of scientists who, in the previous two decades, have begun to warn against too great an emphasis being placed on a molecular casuistic approach as the final pursuit to science (see Duncker 1983). These thinkers were perhaps instrumental in helping to turn the tide, to instruct and encourage fellow researchers to extend their findings from the molecular and to the organismal (see Duncker 1983, 1992a, b; Duncker and Kreite 1987). Having observed the ceca of many different animals for many years and having described their morphology at different levels of study -from the macroscopic to the electron microscopy level - the need to compare and observe these morphological entities in a quantitiative way became increasingly imminent. Quantitative methodol- ogy in morphology requires the use of morphometry, which in the most general terms can be described as the measurement of the forms of animals. As defined by Reith and Meyhew (1988), it is quantitative morphology, i. e., the measurement of structures by any method, including stereology.

Spis treści

1 Introduction.- 1.1 Scientific Aims.- 1.2 General Introduction.- 1.3 Literature Survey.- 1.3.1 General Information - Alimentary Canal.- 1.3.2 Morphometry, Morphometric Techniques, and Quantitative Surveys.- 1.4 Primary Objectives.- 2 Methodology.- 2.1 Introductory Word on Techniques.- 2.2 Methods.- 2.2.1 Animals.- 2.2.2 Fixation.- 2.2.3 Determination of Ground Level of Basal Surface Area.- 2.2.3.1 Small Intestine.- 2.2.4 Determination of Second-Order Enlargement of the Surface Area.- 2.2.4.1 Sampling and Further Fixation.- 2.2.5 Tissue Embedding.- 2.2.5.1 Vertical Sections.- 2.2.6 Determination of Sampling Sites.- 2.2.6.1 Pilot Study.- 2.2.6.2 Alternative Methods for Large Animals.- 2.2.7 Measurements.- 2.2.7.1 Aim.- 2.2.7.2 Calibration.- 2.2.8 Measuring Devices.- 2.2.8.1 Advantages of the Semi-automatic Videoplan Analyzing System.- 2.2.9 Measurement of Microvilli: Pilot Experiment.- 2.2.10 Shrinkage.- 2.3 Discussion.- 2.3.1 Statistical Confirmation.- of Using Three Animals Per Group.- 2.3.2 Fixation.- 2.3.2.1 Method of Choice: Intracorporeal/Intraluminal Fixation.- 2.3.2.2 Other Considerations of Fixed Material.- 2.3.3 Morphometric Techniques.- 2.3.3.1 Measurement of Surface Enlargement.- 2.3.3.2 Changes in Measured Structures Dependent on External Factors.- 2.3.3.3 Microvilli Considerations.- 2.3.4 Scaling Considerations: Relationship to Body Weight.- 2.3.5 Conclusions.- 3 Morphology of the Mammalian Cecum and Colon.- 3.1 Introduction.- 3.2 General Aspects.- 3.3 Terminology.- 3.4 Methodology.- 3.5 Observations.- 3.5.1 Gross Anatomical Aspects.- 3.5.2 Second-Order Enlargements.- 4 Morphometry of the Mammalian Cecum and Colon.- 4.1 Application.- 4.1.1 Areas.- 4.1.2 Volumes.- 4.1.3 Coefficients.- 4.1.3.1 Areas (Coefficient of Gut Differentiation).- 4.1.3.2 Volumes (Coefficient of Volume).- 4.1.4 Area to Unit Volume Relationships.- 4.2 Concluding Discussion.- 4.2.1 Areas.- 4.2.2 Volume.- 4.2.3 Coefficients.- 4.2.3.1 Areas.- 4.2.3.2 Volumes.- 4.2.4 Area to Unit Volume Relationships.- 5 Summary.- References.

Blurb

This treatise combines a detailed methodology that is simple to follow and reconstruct, and can be universally used to determine the surface area or tubular organs, in this special case development for the intestines. It is especially appropriate for large intestine, but can be used for small intestine also. The great advantage is the applicability at the macroscopic and microscopic levels, measuring the entire intestine for determination of a ground or basal area, and using a large encompassing sampling technique to obtain a factor of surface enlargment due to such structural entitities as folds and plicae. A technique to determine the factor of increase due to microvilli is also introduced. Various factors that may influence the measurements are discussed. Application of the technique is presented within the concept of scaling. Numerous regression curves are presented to represent how intestinal surface area correlates with body weight. A unifying and correlating concept between morphology and morphometry is developed. Over 20 species are included.