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Lower leg growth was determined by knemometry in 11 children with short stature, before and during therapy with growth promoting drugs. The growth response of lower leg length was determined by comparing growth velocities over periods of 6 weeks. The growth response of total body height was determined by comparing the growth velocity during 3 months of therapy with the growth velocity over 1 year before therapy. Significant knemometric growth responses were always associated with positive height responses, but smaller knemometric responses were associated with positive as well as negative height responses.
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We investigated the effects of various growth inhibitory substances on fibronectin secretion in cultured normal human keratinocytes. Fibronectin secretion in keratinocytes was expressed by two methods: immunofluorescent staining of cells with anti-human fibronectin antibody, and sodium dodecyl-sulphate-polyacrylamide gel electrophoresis of [35S]-labeled proteins secreted by the cells followed by autoradiography. With immunofluorescent staining, the extracellular fibronectin was observed as coarse fibrils only in some cells of the control culture, while cells treated with 20 ng/ml transforming growth factor-beta 1 (TGF-beta 1) showed intense fluorescences in a radiating pattern around most of the cells, indicating that TGF-beta 1 markedly increased fibronectin secretion in keratinocytes. Analysis of [35S]-methionine labeled proteins also revealed that TGF-beta 1 increased fibronectin secretion eight fold in culture medium. TGF-beta 2 has also induced weak increase of fibronectin secretion 1.8 fold in keratinocytes. In contrast, other growth inhibitory substances, such as tumor necrosis factor-alpha, 1,25-dihydroxyvitamin D3 and cyclosporin A, did not show any significant effects on fibronectin secretion. These results indicated that increase of fibronectin secretion is not associated with growth inhibitory effect, but rather with a specific effect of TGF-beta.
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A number of growth promoting substances used in plant tissue culture were investigated for their effect on cultures of malaria parasites. In all, seven such growth promoting substances were employed. Out of these, only three substances, namely indoleacetic acid, indolebutyric acid and gibberellic acid improved P. falciparum growth in vitro.
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Serum-free chemically defined medium for hybridoma and parental myeloma cultivation was developed on the basis of testing of individual substances supporting hybridoma growth under serum-free conditions. Optimized concentrations of transferrin, insulin, ethanolamine, linoleic acid, serum albumin, ascorbic acid, hydrocortisone, and trace elements could substitute serum. Developed serum-free hybridoma (SFH) medium differs from analogous previously described media mainly by a more complete combination of growth-supporting supplements and by the presence of ascorbic acid and hydrocortisone. Growth comparable with that in the medium supplemented with 10% bovine serum was achieved with four hybridomas and two myelomas. SFH medium was also suitable for long-term cultivation of hybridomas without cessation of monoclonal antibody production. Growth potency and the specific growth requirements of hybridomas in serum-free medium are, to a large degree, determined by parental myeloma.
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The purpose was to observe the effect on sarcomagenesis of 3 substances reported to inhibit neoplastic growth--interferon alpha-2/alpha-1 hybrid (IFN), 5-iodo-2-deoxyuridine (IUdR) and methylglyoxal bis(guanylhydrazone) (MGBG). Inhibitory effect might help diminish the sarcoma risk of human implants. The substances were applied respectively to groups of 25mm cellulose filters which were implanted subcutaneously 1 per animal in randomly assigned respective groups of 50 female BALB/c mice. The implant sites were palpated weekly. On detection of a tumour the animal was sacrificed. The number of tumours arising and the accumulated weeks of exposure to the implants were recorded per group and compared to those of controls with untreated filters. Tumour incidence in the 2 IFN groups was 33/45 and 35/48 mice--160 per cent that of the controls, 22/48 (chi-square p < 0.05). In the IUdR group tumour incidence was 24/44 mice--194 per cent that of controls (p < 0.05), and in the MGBG group 15/43--122 per cent that of controls (p < 0.75). Although the substances inhibit tumour growth in man, they did not inhibit but increased film sarcomagenesis, not significant for MGBG. Observation of the effects of such substances with dual neoplastic activity may furnish clues to the control processes of neoplasia.
The investigation studied the occurrence of growth-inhibitory substances in barley grain during postharvest ripening cultivated in different climatic zones. It was shown that the amount of inhibitory substances accumulated in grain was higher under unfavourable ripening conditions. Heat treatment of freshly harvested barley accelerated their disintegration. The disappearance of growth-inhibitory substances coincided with the termination of postharvest ripening of barley grain.
I. Lysogenic B. megatherium 899a (de Jong, 1931) produces two types of phage (Gratia, 1936 c) T and C. The T phage forms cloudy plaques and gives rise to fresh lysogenic strains (Gratia, 1936 b) when added to the sensitive strain of megatherium. It may or may not cause lysis, depending on the media (Northrop, 1951). The C phage occurs very rarely) forms clear plaques, does not give rise to lysogenic strains, and causes complete lysis of the sensitive strain under all conditions tested, provided infection occurs. If C phage is added to the sensitive strain, and the mixture allowed to stand, or made into a hanging drop preparation, the infected cells stop growing and lyse completely after 60 to 80 minutes with the liberation of from 50 to 200 phage particles per cell. If, however, C phage is added to a rapidly growing culture of B. megatherium and the suspension shaken at 34 degrees , the cells continue to grow and divide for 50 to 60 minutes, after infection has occurred. They then lyse, with the liberation of from 1000 to 2500 phage particles per cell. II. The following determinations have been made on megatherium sensitive cells growing in 5 per cent peptone at different stages of growth. (1) Growth rate of infected and uninfected cells; (2) RNA, DNA, and protein content; (3) volume of the cell; (4) phage yield per cell by plaque count; (5) phage yield per cell by cell and plaque count; (6) lysis time. The growth rate decreases as the cell concentration increases. The lysis time and the protein N per cell are nearly independent of the growth rate; all the other values increase as the growth rate increases. The ratio See PDF for Equation is nearly constant. RNA and DNA per cell increase less rapidly than the volume, so that NA per unit volume is not constant, but decreases as the size of the cell increases. The phage yield measured under conditions in which the infected cells do not grow (by plaque count) is very nearly proportional to the size of the cell. The phage yield per cell, under conditions in which the infected cells do grow, increases more rapidly than the size of the cells. The phage yield per cell under these conditions may be calculated by the equation See PDF for Equation The determining factor for the variation in phage yield is the growth rate of the cells. This, in turn, is determined by the composition of the medium. III. The growth and phage production of megatherium 899a have been determined in the presence of the following substances: aureomycin, bacitracin, chloromycetin, gramicidin, Merck AB631, Merck AB191, Merck AB624, penicillin, streptomycin, terramycin, tyrothricin, usnic acid, acetone, chloroform, ethyl alcohol, formaldehyde, gentian violet, glycerin, maleic hydrazide, methyl alcohol, phenyl mercuric acetate, sodium fluoride, sulfanilamide, toluene, and urethane. In every case, the lowest concentration of the substance which completely inhibits growth, is also the lowest concentration which completely inhibits phage production. One antibiotic, Merck AB81, causes increased phage production in concentrations which partially inhibit growth, and low phage production in concentrations which completely inhibit growth (as determined by turbidity). Short exposure to ultraviolet light also decreases the growth rate, with increase in phage production. Longer exposure, which completely inhibits growth (as determined by turbidity) results in lysis and phage liberation.
The human renal carcinoma cell (RCC) line ACHN proliferates in the absence of exogenous growth factors and secretes a 178-kilodalton growth-promoting substance (GPS). Complementary DNA (cDNA) was isolated that coded for polypeptides antigenically cross-reactive with GPS. Nucleotide sequencing of the cDNA showed strong homology with human fibronectin (FN). The deletion of an adenine in human FN codon 1482 caused a reading-frame shift that predicted early termination of translation after 1518 amino acid residues. Western immunoblotting human FN and GPS with anti-human FN antibodies showed that GPS was a truncated FN. Previous work found that malignant cells synthesized, bound, and deposited into the extracellular matrix decreased amounts of FN. Addition of this substance to transformed cells changed their morphology but not their rate of growth. By contrast, partial proteolysis of FN resulted in a prominent 180-kilodalton fragment that stimulated DNA synthesis. Similar to this finding, the authors showed that truncation of fibronectin during synthesis appeared to unmask latent DNA synthetic stimulating activity. Polymerase chain reaction methods using genomic DNA from normal kidneys and RCC and primers specific for the GPS-human FN gene showed two products of identical size, indicating that genomic amplification did not cause activation of the human FN gene in RCC to produce GPS. Restriction-fragment length analysis demonstrated identical patterns in DNA extracted from both normal kidneys and RCC, suggesting that chromosomal rearrangements did not activate the GPS-human FN gene. This study showed that genetic changes detectable only by DNA sequencing can explain the activation of the normal human FN gene to produce GPS, a product important for autologous growth stimulation of RCC.
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The accuracy of an automated system for the microbiological assay of antibiotics was increased by improvement attendant to connection to an on-line computer. The system was used to investigate the suitability of four forms of interpolation formulas by assaying for chlortetracycline and erythromycin. The calibration lines were prepared as point-to-point straight-line approximations and as cubic equations. Cubic equations through four calibration points were preferred. Since the automated system was a four-channel instrument, a separate response line was prepared for each channel. Combining the four response lines into one could substantially degrade the accuracy and precision of assays. A new general equation relating the response of the test organism to concentrations of active materials was used to account for factors in addition to the antibiotic upon the dose-response line. Some of these factors were: diluents, growth substances, relative proportions of mixed antibiotics, pH and buffer capacities of the sample solution and assay broth, salts, and organic compounds in samples and not in standard solutions. The equation was used to show under what conditions the dose-response lines of mixtures and single-component antibiotics could be the same. It could also account for the nonspecific nature of turbidimetric assays. The equation showed assay biases to be caused not by differences in composition of antibiotics in standards and samples but by differences in other substances affecting growth of the test organism. A new dose-response line applicable to assays using Klebsiella pneumoniae was described.
Dimethylsulfoxide-soluble particles (DSP) from cigarette smoke and ultraviolet light caused a low degree (cell death less than 30%) and high degree (cell death 60-90%) injury to bovine arterial endothelial cells and smooth muscle cells in culture. Conditioned medium from low degree injured endothelial cells and smooth muscle cells generally inhibited DNA synthesis in new smooth muscle cells or endothelial cells while high degree injury increased DNA synthesis in new cells. Specifically, the growth stimulating activity from endothelial cells was decreased after low degree injury but increased after high degree. UV light released more growth stimulating substances from smooth muscle cells after both low and high degree injury. The release of growth inhibiting substances was dependent on both cell kind and degree of injury. In co-culture low and high degree DSP injury to endothelial cells inhibited smooth muscle cell proliferation, which was in contrast to the effect of conditioned medium from high degree injured endothelial cells. Conditioned medium from endothelial cells treated with LDL and glucose inhibited DNA synthesis in smooth muscle cells. It is concluded that injury to endothelial cells or smooth muscle cells will modify the release of growth inhibiting and growth stimulating activity and that this release will depend on cell kind as well as degree and kind of the injurious stimulus.
A new type of cell growth inhibitory substance was isolated and purified from a powder of the root of Panax ginseng C.A. Meyer, which has been commonly used for the treatment of various disease as a commercial medical drug by the name of Korean Red Ginseng Powder. Data from the infrared spectra, proton and carbon-13 nuclear magnetic resonance, and high resolution mass spectra were identical with those of authentic panaxytriol. Cell growth inhibition by panaxytriol seemed to be tumor-specific. Its action was supposed to be more dose-dependent than time-dependent. In vivo antitumor efficacy of panaxytriol was tested against C57BL/6 mice transplanted with B 16 melanomas. Panaxytriol (40 mg/kg) administered intramuscularly produced significant tumor growth delays in mice (p less than 0.01).
In this study, we analysed the modulation of keratinocyte growth factor (KGF) mRNA expression in human dermal fibroblasts cultured either in monolayer or within a collagen matrix (dermal equivalent). In monolayer cultures, KGF expression by quiescent fibroblasts was stimulated by different growth substances such as serum, epidermal growth factor and basic fibroblast growth factor. Moreover, we demonstrated that the induction of this gene was mediated by at least 2 different signalling pathways involving protein kinase C (PKC) and cAMP. In dermal equivalents, we observed that the collagen matrix negatively modulated KGF mRNA expression. Indeed, among the growth substances used, only the serum slightly stimulated KGF expression. Nevertheless, as in monolayers, this induction involved at least PKC and cAMP signalling pathways. As the collagen matrix can modulate fibroblast growth, we also studied KGF expression in growing fibroblasts from either monolayer cultures or dermal equivalents. We then showed that this collagen matrix negatively influenced KGF expression independently of the proliferative state of fibroblasts. All these results underline the fact that KGF mRNA expression by human dermal fibroblasts is induced by different substances; however this expression can be modulated by fibroblast-matrix interactions.