Enzymes of cultured human fibroblasts. IV. Enzyme activity in trisomy C strains]

The activity of five enzymes (AIP, AcP, GOT, LDH, MDH) was investigated in four cell strains derived from spontaneous abortuses with C-trisomy (three cell strains with trisomy 7, one--with trisomy 9). Significant differences in the activity of three enzymes were revealed. In all the strains AIP activity was lower and GOT activity--higher than in diploid strains. Lowering of AcP level was found in three strains (two cell strains with trisomy 7, one--with trisomy 9). The data obtained are evaluated as a result of disturbed regulatory interrelations in an abnormal genome.     

Effects of neuropeptides on growth of cultivated rat molar pulp fibroblasts

The effect of the neuropeptides substance P (SP), neurokinin A (NKA), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) on DNA synthesis of dental pulp cells was investigated in cells grown from molar tooth bud explants from 4–6 days old rat pups. A concentration response-assay of the proliferative response of pulpal cells was performed with SP, NPY, NKA, CGRP and VIP (0.01 to 1 nM) in the presence of EGF (10 ng/ml), hydrocortisone (0.4 μg/ml) and 3% FCS, using [³H]thymidine incorporation. The results showed that SP, NKA and CGRP, but not NPY and VIP, increased the cell number in a concentration-dependent manner, with maxima at 10⁻¹⁰ – 10⁻⁹ M (SP, NKA) and 10⁻⁷ M (CGRP). No potentiating effect was noted when cells are simultaneously stimulated with SP and CGRP. The finding that SP, NKA and CGRP have growth regulatory properties on pulpal cells in vitro suggests that sensory neuropeptides may be involved during pulpal development or in wound healing after pulpal injury.     

The nutrition of animal tissues cultivated in vitro. IV. Amino acid requirements of chick embryonic heart fibroblasts

1. The amino acid requirements of freshly explanted chick embryonic heart tissues cultivated in completely synthetic media have been determined, employing a nutritional depletion technique. Arginine, histidine, lysine, tyrosine, tryptophan, phenylalanine, cystine, methionine, threonine, leucine, and valine were found to be essential. Serine, isoleucine, glycine, and glutamine were found to be non-essential. Glutamic acid, aspartic acid, alpha-alanine, proline, and hydroxyproline were found to be inhibitory in this test system. 2. A total amino acid level of approximately 100 mg. per cent was found to be optimal and DL-amino acids were found to be non-toxic, unless used in high concentrations. 3. A comparison has been made of the amino acid requirements of various types of tissue cultures, of the chick, and of man and certain differences in these requirements have been discussed.     

Cytologic observations on the effects of metallocene dichlorides on human fibroblasts cultivated in vitro

The effects of the organometallic cytostatic agents titanocene dichloride (TDC) and vanadocene dichloride (VDC) and of the inorganic cytostatic drug cis-diamminedichloroplatinum(II) (DDP) on the morphologic appearance of human embryonal fibroblasts cultivated as monolayers in vitro were analyzed by light and electron microscopy. All three substances induced similar structural changes which consisted of nuclear as well as cytoplasmic alterations. Many fibroblasts enlarged but the nuclear volume increased more extensively than that of the cytoplasm. The nuclear envelopes underwent invagination so that segmented nuclei were formed and the nucleoli increased in size and density. Within the cytoplasm there was evidence of conspicuous protein synthesis, characterized morphologically by an increase in the size and number of mitochondria, Golgi apparatuses and of cisternae of the rER. The phenomena observed are interpreted as indicating unbalanced cell growth characterized by a selective inhibition of DNA synthesis, coupled with progressive RNA and protein syntheses.     

Cytological and cytochemical effects of a liver extract from an adult rat on chick embryo hepatocytes and fibroblasts cultivated in vitro]

The effects of an extract from adult liver on chick embryo hepatocytes and fibroblasts cultivated in vitro are studied with cytological and quantitative cytochemical methods. This substance inhibits the multiplication of hepatocytes adn prevents these cells from entering into the S phase of the cycle. No effect is observed on the chick embryo fibroblasts. Not any morphological alterations are observed in the two cell types.