Life Sciences Commons^™

Quantitative Measurement From Vascular Casts, Ralph G. Kratky, Christine M. Zeindler, Dorian K. C. Lo, Margot R. Roach

Scanning Microscopy

A review of quantitative measurements show casting materials shrink from 0.2 - 20% and have viscosities ranging from 1.4 - 100,000 centipoise. Blood vessels have highly variable mechanical properties. Some microvessels are very stiff having little change in dimensions with pressure. Larger vessels generally change diameter significantly but show highly variable changes in length with pressure. Perfusion fixation does not fix the dimensions of blood vessels. Dog carotid arteries well fixed with glutaraldehyde at physiologic dimensions retain ≈20% of their elastic recoil circumferentially and ≈30% longitudinally. We recommend vascular casting as a method of accurately measuring the vasculature if care …

The Opisthonephric Blood Vascular System Of The Chicken Embryo As Studied By Scanning Electron Microscopy Of Microvascular Corrosion Casts And Critical Point Dried Preparations, H. Ditrich, H. Splechtna

Scanning Microscopy

Microvascular corrosion casts of chicken embryos between four and 19 days after fertilization have been prepared. The developing kidney was investigated with scanning electron microscopy (SEM). The injection technique and resin composition were modified in order to facilitate the complete replication of native blood vascular systems of specimens as small as 15 mm body length. The development of the opisthonephros was followed from near the beginning of its function until a vascular development comparable to the adult situation was reached. Critical point dried glomeruli show the differentiation of the glomerular visceral epithelium (podocytes) from initially epithelioid to highly branched forms. …

Calcium Levels In Ruffle-Ended And Smooth-Ended Maturation Ameloblasts, S. H. Ashrafi, D. R. Eisenmann, A. E. Zaki

Scanning Microscopy

Scanning electron microscopy was used to distinguish the topographical characteristics of two maturation ameloblast types in freeze-dried blocks of enamel organ tissue. This distinction was based primarily upon the configuration of the distal ends of the ameloblasts and the presence or absence of wide intercellular spaces.

Energy dispersive x-ray spectrometry was applied to compare calcium levels in various regions of tissue identified as constituting either ruffle-ended or smooth ended ameloblasts. Greater levels of calcium were found in the distal ends of the ruffle-ended cells than in their proximal ends. In addition, greater calcium levels were found in the distal ends …

An Electron Microscopic Study Of The Adherence Of Lactobacillus Acidophilus To Human Intestinal Cells In Vitro, S. K. Hood, E. A. Zottola

Food Structure

In this study, transmission electron microscopy was used to visualize the adherence of Lactobacillus acidophilus to human intestinal tissue cells (HITC) in vitro. There appeared to be a layer of electron dense material on the bacterial cell and on the intestinal cell which may mediate adherence. When L. acidophilus attached to intestinal tissue cells after a short contact period, it did not appear to disrupt the integrity of the intestinal cell. Treatment of the bacterium with sodium periodate and concanavalin A reduced the adherence to HITC, suggesting that a carbohydrate was involved. Electron micrographs of periodate-treated cells revealed that the …