Cryofixation, ultracryomicrotomy, and X-ray microanalysis of enterocytes from chick duodenum: Vitamin-D-induced formation of an apical tubulovesicular system
- Baylor Univ. Medical Center, Dallas, TX (USA)
New methods of tissue preparation were developed to study the morphology and distribution of calcium ions in duodenal enterocytes from normal, rachitic, and vitamin D-replete (either cholecalciferol (CC) or 1,25-dihydroxycholecalciferol (1,25-DHCC) treated) chicks. Frozen hydrated sections were prepared from cryofixed tissues by ultracryomicrotomy at -125 degrees C. Sections were subsequently freeze-dried by increasing the temperature to -100 degrees C. The latter temperature was maintained throughout both the structural and elemental analyses. In cells from normal, rachitic, and vitamin D-treated (CC) animals the brush border from lanthanum-infused tissues was electron dense and calcium-lanthanum positive by x-ray analysis. In the absence of lanthanum, i.e., sucrose-infused duodena, the microvilli were still calcium positive. In the terminal web region of normal and CC-treated enterocytes, numerous, apparently interconnected, tubules and vesicles were seen. Vacuole-like structures were also seen. Such structures were especially prominent in the enterocytes from the vitamin-treated (CC) animals. Except for the vacuoles, the tubules and vesicles were electron dense in the lanthanum-infused duodena, and clear in sucrose-infused tissues. In both instances, the structures were calcium positive. Similar, but even larger structures were seen below the terminal web. Here however, the tubules and vesicles seemed to be organized into multiple complex interconnecting networks, i.e., tubulo-vesicular complexes. Both the tubules and the vesicles seemed to be interconnected via smaller channel-like entities. The extensiveness of this structure was better appreciated in the enterocytes from lanthanum-infused tissues, where it appeared similar in structure and complexity to an en face view of the sarcoplasmic reticulum of skeletal muscle.
- OSTI ID:
- 5799624
- Journal Information:
- Anatomical Record; (USA), Vol. 229:2; ISSN 0003-276X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM COMPOUNDS
TISSUE DISTRIBUTION
SMALL INTESTINE
ELECTRON MICROPROBE ANALYSIS
VITAMIN D
BIOLOGICAL EFFECTS
CHICKENS
CYTOPLASM
HISTOLOGICAL TECHNIQUES
MORPHOLOGY
RICKETS
SAMPLE PREPARATION
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
BIRDS
BODY
CELL CONSTITUENTS
CHEMICAL ANALYSIS
DIGESTIVE SYSTEM
DISEASES
DISTRIBUTION
FOWL
GASTROINTESTINAL TRACT
INTESTINES
METABOLIC DISEASES
MICROANALYSIS
ORGANS
SKELETAL DISEASES
VERTEBRATES
VITAMINS
550602* - Medicine- External Radiation in Diagnostics- (1980-)