Cell proliferation in the basal layer of the stratified squamous epithelium of the esophagus in hypophysectomized rats

Some different types of models of cell proliferation are discussed. The importance of basing the models on experimental data is emphasised, but warnings are given about some of the pitfalls in fitting models of data. The importance of investigating alternative models which might lead to similar experimental findings is stressed. The use of simulation to assess the ability of an analytical method to extract correct information from experimental data is advocated. In this instance, the modelling process takes place in advance of the data collection. Models described relate to cell proliferation in a transplantable tumor, the prostate of the castrate mouse stimulated with testosterone, and stratified squamous epithelium. Experimental techiques include measurment of tumor size, calculation of labelling and mitotic indices over time, and the fraction labelled mitoses method.

Download Full-text

Some preliminary observations on the histological development of the fore-stomachs of the lamb I. Histological changes due to age in the period from 46 days of foetal life to 77 days of post-natal life

The Journal of Agricultural Science ◽

10.1017/s0021859600049303 ◽

1961 ◽

Vol 57 (3) ◽

pp. 335-341 ◽

Cited By ~ 36

Author(s):

I. D. Wardrop

Keyword(s):

Squamous Epithelium ◽

Basal Layer ◽

Mucosal Surface ◽

Age Changes ◽

General Survey ◽

Histological Changes ◽

Foetal Life ◽

Stratified Squamous Epithelium

1. A general survey of the histological changes of the fore-stomachs of the lambs from 46 days of foetal life to 77 days of post-natal life is presented.2. In all the rumen foetal specimens the mucosal surface was smooth. At birth small, conical papillae were visible and from this age onwards these papillae increased rapidly in size and tended to be long and tongue-shaped in appearance. Little change occurred in the appearance of the rumen papillae after 56 days of age.3. The outlines of the reticulum reticular ribs were visible in the 100-day-old foetal specimen. At birth the normal honeycomb-like structure of the reticulum was well developed, but the papillae on and between the reticular ribs were small and had rounded tips. From 20 days of age onwards the reticulum features increased in size and the papillae became pointed in shape.4. At 46 days of foetal life the omasum wall was folded to form developing laminae and by 70 days of foetal life laminae of four orders were present. The main age changes in the appearance of the mucosal surface from this age onward was an increase in the length of the laminae, the formation of small conical papillae on the laminae, and an increase in the inter-laminae spaces.5. All three fore-stomachs showed the same general histological changes with age. The epithelium changed from a stratified cuboidal type in the foetal specimens to a keratinized, stratified, squamous epithelium in the post-natal specimens. The basal layer of the epithelium became folded to form papillae, reticular ribs and laminae, and in the rumen and reticulum further folding of this layer took place to form papillary bodies.

Download Full-text

Prenatal development of the lingual epithelium in goat (Capra hircus)

Journal of Applied and Natural Science ◽

10.31018/jans.v9i1.1207 ◽

2017 ◽

Vol 9 (1) ◽

pp. 421-426

Author(s):

Yousuf Dar ◽

Kamal Sarma ◽

Shalini Suri ◽

Jonali Devi

Keyword(s):

Gestational Age ◽

Squamous Epithelium ◽

Age Groups ◽

Basal Layer ◽

Prenatal Development ◽

Capra Hircus ◽

Lingual Epithelium ◽

Stage Of Development ◽

Group I ◽

Stratified Squamous Epithelium

The present study was conducted on the tongue of 18 goat foetii divided into three prenatal age groups viz- Group I ( below 50 days of gestation), Group II ( between 50-100 days of gestation) and Group III ( above 100 days of gestation to up to full term) containing 6 number of foetii in each group to study the sequential events in regard to histological development of the same in goat foetii. The tongue was lined by 3-4 layered epithelium in the foetus at 40 days of gestation (CRL= 2.40cm). The lingual epithelium consisted of a basal layer of cuboidal cells with squamous to cuboidal shaped more superficial layers. At 62 days of gestation (CRL= 10.10 cm), the lamina epithelialis of the tongue of goat foetus was distinctly stratified. At this stage of development, the epithelial layers could be divided into dark basal and a light apical or superficial zones. At 80-84 days of gestation (CRL=15.3 to 16.0 cm), the stratified squamous epithelium of the tongue was better developed both on the dorsum and ventral surfaces. At 93 days of gestation (CRL= 20.6 cm), the stratified squamous epithelium of the tongue was well developed and all the layers of the epithelium could be observed. In the foetii of gestational age of 100 days onwards, the lingual epithelium of the tongue showed various degrees of keratinization. Thus, it was concluded that the tongue of goat was lined with 3-4 layers of epithelial cells. The degree of stratification increased with an increase in gestational age. Also with age there was an increase in the degree of keratinization. This research further implicated that with further advancement of age the basal layer of the epithelium comprised high cylindrical cells along with well defined basement membrane. The decrepancy of histogenesis and keratogenesis between different species may be due to difference in the duration of the gestation period.

Download Full-text

Comparison of Multiple Injections with Continuous Infusion of Tritiated Thymidine, and Estimation of the Cell Cycle Time

Journal of Cell Science ◽

10.1242/jcs.5.3.575 ◽

1969 ◽

Vol 5 (3) ◽

pp. 575-582

Author(s):

W. K. BLENKINSOPP ◽

C. W. GILBERT

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Continuous Infusion ◽

Cycle Time ◽

Squamous Epithelium ◽

Tritiated Thymidine ◽

Intraperitoneal Administration ◽

Cell Cycle Time ◽

Multiple Injections ◽

Stratified Squamous Epithelium

Labelled nuclei were counted in stratified squamous epithelium in mice killed after 24 h intraperitoneal administration of tritiated thymidine to label cells synthesizing deoxyribonucleic acid. Multiple injections produced the same result as an infusion of tritiated thymidine given after 24 h infusion of saline, but infusion of tritiated thymidine alone produced a different result. Thus, cell proliferation was depressed during the first 24 h of continuous infusion but was normal during the second 24 h. Comparison of proliferation of the oesophageal epithelium at the level of the thyroid and at the level of the diaphragm showed no difference between the two. Comparison of male with female mice given 72-h infusions of tritiated thymidine showed that cell proliferation occurred at the same rate in both. The cell cycle time was estimated in the epithelium of the oesophagus and tongue by comparison of mice given a single injection with mice given multiple injections of tritiated thymidine.

Download Full-text

Junction of the Epithelium and Lamina Propria of the Bovine Rumen Mucosa

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060350 ◽

1967 ◽

Vol 25 ◽

pp. 68-69

Author(s):

Al W. Stinson

Keyword(s):

Osmium Tetroxide ◽

Squamous Epithelium ◽

Short Chain Fatty Acids ◽

Chloride Ions ◽

Fermentation Products ◽

Ruminant Species ◽

Protective Shield ◽

Stratified Squamous Epithelium ◽

Lead Hydroxide ◽

Acetic Acids

The stratified squamous epithelium which lines the ruminal compartment of the bovine stomach performs at least three important functions. (1) The upper keratinized layer forms a protective shield against the rough, fibrous, constantly moving ingesta. (2) It is an organ of absorption since a number of substances are absorbed directly through the epithelium. These include short chain fatty acids, potassium, sodium and chloride ions, water, and many others. (3) The cells of the deeper layers metabolize butyric acid and to a lesser extent propionic and acetic acids which are the fermentation products of rumen digestion. Because of the functional characteristics, this epithelium is important in the digestive process of ruminant species which convert large quantities of rough, fibrous feed into energy.Tissue used in this study was obtained by biopsy through a rumen fistula from clinically healthy, yearling holstein steers. The animals had been fed a typical diet of hay and grain and the ruminal papillae were fully developed. The tissue was immediately immersed in 1% osmium tetroxide buffered to a pH of 7.4 and fixed for 2 hrs. The tissue blocks were embedded in Vestapol-W, sectioned with a Porter-Blum microtome with glass knives and stained with lead hydroxide. The sections were studied with an RCA EMU 3F electron microscope.

Download Full-text