Lymphocyte-induced angiogenesis: a morphometric study in the chick embryo chorioallantoic membrane.

A morphometric analysis was carried out on the chorioallantoic membrane (CAM) vasculature in chicken embryos treated (1) with phytohemagglutinin (PHA), (2) with supernatants of cell cultures of normal human T lymphocytes and (3) of T lymphocytes stimulated with PHA in order to evaluate their angiogenic properties. In the left chorioallantoic artery, the number of primary collaterals, and the number and length of secondary and tertiary collaterals were measured. In the series treated applying procedures 1 and 3, the mean value of the total number of all the collaterals was higher than that of the normal-developing CAM vessels, while the length of the secondary and tertiary collaterals was lower than that of the normal-developing blood vessels. In the series treated following procedure 2, no statistically significant differences were observed between experimental and control series in any parameters evaluated. The possible significances of these morphological findings are discussed with reference to the angiogenic roles played by human T lymphocytes, probably determined by lymphokines released after the activation of these cells by PHA, and by PHA alone, probably dependent on its aspecific mitotic activity.     

Computerized morphometric analysis of the chick embryo duodenum organogenesis

A computerized morphometric analysis was performed on histological sections of the proximal and distal limbs of the chick embryo duodenum, from the 8th to the 15th day of incubation, with the aim of evaluating the quantitative aspects of organogenesis. A semiautomatic digital system was used. The areas of total section, of the lumen, of the wall and of its components (subserous stratum, muscle layer, lamina propria, epithelium) and the thickness of the epithelium and muscle layer were measured; the mean +/- S.E.M. of the values obtained was calculated. The percentage of shrinkage, due to the histological procedures, was calculated for each day. The values obtained were added to the measurements of each area and thickness thus giving the true value of each parameter measured. The differences between the mean values of the areas of the proximal and the distal tract were statistically evaluated. Exponential curves and r coefficient were determined to evaluate the general growing pattern of the mean area of the components of the duodenal wall, as a function of age. The main results are the following: the areas of the wall components of the proximal limb are always greater than the corresponding areas of the distal limb of the duodenum. There are some differences between the proximal and the distal limbs of the duodenum in the growing pattern of the intestinal wall components. The anlage of the duodenum also has a different developmental pattern compared with that of the chick embryo ileum.     

Early development of the chick embryo

The ultrastructure of the early chick embryo was investigated, using scanning (SEM) and transmission electron microscopy (TEM). Eggs were obtained from the shell gland by injecting hens intravenously with a synthetic prostaglandin or arginine vasopressin. Embryos were examined during late cleavage (stages IV–VI, Eyal-Giladi and Kochav, '76), formation of the area pellucida (stages VII–XI), and formation of the hypoblast (stages X–XIV). SEM highlighted the reduction in cell number at the underside of the embryo during formation of the area pellucida although it became apparent that the thickness of the embryo is not reduced to a single layer of cells at stage X. In addition, blastomeres at the perimeter of embryos (stages V–VI) project filopodial extensions onto a smooth membrane that separates the sub-embryonic cavity from the yolk. During hypoblast formation, epiblast cells generate stellate projections at their basal aspect, thus providing a meshwork for the advancing secondary hypoblast cells. By stage XII the epiblast was one cell thick and reminiscent of a columnar epithelium when viewed transversely. Cells of the deep portion of the posterior marginal zone were distinguished morphologically in the stage XII embryo by their many cell surface projections and ruffled appearance. Blastomeres at the perimeter of stage V–VI embryos projected filopodial extensions onto a smooth membrane which separates the sub-embryonic cavity from the yolk. This membrane is presumed to be confluent with the cytolemma. Evidence is presented demonstrating the presence of intracellular membrane-bound droplets which are hypothesised to contain sub-embryonic fluid. © 1993 Wiley-Liss, Inc.     

Kynurenine metabolism in the development chick embryo

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1. In the embryonic chick liver during the midperiod of development (8–12 days), kynureninase is the primary enzyme involved in the catabolism of kynurenine. Kynurenine aminotransferase was not found.     

Histochemical analysis of goblet cell mucins in the chick embryo colon

The histochemical characteristics of colonic epithelial mucins were investigated in the chick embryo. At the 14th day of incubation it was possible to demonstrate the presence of glycogen. At the 15th day a few epithelial cells showed the presence of neutral and sialylated mucins. On the 16th day, also sulfated secretory material was detectable together with neutral and sialylated mucins in cells with the typical shape of goblet cells. From the 17th day to the 20th day of incubation the two types of acid mucins appeared in some cells to be placed in distinct zones of the supranuclear cytoplasm. At the 21st day, neutral, sialylated and sulfated mucins were all present in the majority of goblet cells, which were found mainly in the epithelium lining the crypts.     

beta-N-acetylhexosaminidase isoenzymes during chick embryo development

1. Two forms (I and II) with acidic pH optima and a neutral form of beta-hexosaminidase has been separated by DEAE-cellulose chromatography and characterized in skin and lung of 7, 9, 11, 14 day chick embryos and 1 day old chicken. 2. Forms I and II are similar to hexosaminidase A and B for their behaviour on DEAE-cellulose chromatography, Concanavalin A-Sepharose column and thermal stability. 3. Neutral form has a neutral pH optimum and higher molecular weight and a more acidic I. P. than forms I and II, a low beta-N-acetylgalactosaminidase activity and it is not bound by a Concanavalin A-Sepharose column and in that resemble hexosaminidase C and/or other neutral hexosaminidases. 4. We have found differences in the percentage of neutral form and in the specific activities of the extracts in the skin in different stages of development. 5. No significant differences were observed in the lung.