Intensity of RNA and protein synthesis in fibroblasts of mice in wound healing]

The RNA and protein synthesis in mouse fibroblasts was studied on the 3d and 7th day of wound healing by electron-microscopic autoradiography with double-labeling technique. It was shown that the ratio between the protein synthesis in cytoplasm and the RNA synthesis in the nucleus of some cells significantly differed resulting in relative predominance of one of the two processes studied in the fibroblasts during both terms of wound healing. On an average the fibroblasts were characterized by a higher level of the protein synthesis on the 3d day of wound healing. This average high level was provided by an increase in the fibroblasts, in which the protein synthesis prevailed over the RNA one.     

Autoradiographic analysis of the effect of potassium orotate on the intensity of uridine-5 3H and proline-3H incorporation into wound fibroblasts]

The intensity of uridine-53H and proline-3H incorporation into fibroblast nuclei and cytoplasm as well as into intercellular spaces was studied in wound healing of mice given potassium orotate and in the control animals. It was shown that proline-3H incorporation was more intensive than that of uridine-53H. At the same time a significant increase in RNA synthesis in fibroblasts under the action of potassium orotate, and a less pronounced rise in proline-containing protein synthesis were noted in similar conditioelationships correlate with the fibroblast ultrastructural changes in the process of their differentiation.     

Cytophotometric study of blood neutrophil and wound exudate myeloperoxidase in experimental wound healing

Changes in the activity of blood neutrophil and wound exudate myeloperoxidase (MP) have been studied cytophotometrically on the models of aseptic and infected experimental wounds in 220 male Wistar rats on the 1st-10th, 12th and 15th day after wounding. It has been established that changes in MP activity reflect the nature and stages of the pathological process and the animals' reaction to it. MP activity is significantly higher in animals with infected wounds, which indicates the intensity and duration of the inflammatory process and is of prognostic value.     

Modelling the interaction of keratinocytes and fibroblasts during normal and abnormal wound healing processes

The crosstalk between fibroblasts and keratinocytes is a vital component of the wound healing process, and involves the activity of a number of growth factors and cytokines. In this work, we develop a mathematical model of this crosstalk in order to elucidate the effects of these interactions on the regeneration of collagen in a wound that heals by second intention. We consider the role of four components that strongly affect this process: transforming growth factor-β, platelet-derived growth factor, interleukin-1 and keratinocyte growth factor. The impact of this network of interactions on the degradation of an initial fibrin clot, as well as its subsequent replacement by a matrix that is mainly composed of collagen, is described through an eight-component system of nonlinear partial differential equations. Numerical results, obtained in a two-dimensional domain, highlight key aspects of this multifarious process, such as re-epithelialization. The model is shown to reproduce many of the important features of normal wound healing. In addition, we use the model to simulate the treatment of two pathological cases: chronic hypoxia, which can lead to chronic wounds; and prolonged inflammation, which has been shown to lead to hypertrophic scarring. We find that our model predictions are qualitatively in agreement with previously reported observations and provide an alternative pathway for gaining insight into this complex biological process.     

Control of protein synthesis in human fibroblasts by intracellular potassium

Intracellular potassium ion (K⁺) in cultured human fibroblasts (HF cells) was maintained at reduced steady-state levels by incubating cells in various ouabain concentrations. Small decreases in cell K⁺ had no effect on protein synthesis and cell growth, but when cell K⁺ fell below 60–80% of control levels, the rate of protein synthesis decreased in proportion to further reductions in K⁺. DNA synthesis was also inhibited, presumably because of its dependence on protein synthesis. On the other hand, RNA synthesis remained uninhibited over a wide range of K⁺ concentrations, an effect characteristic of many specific inhibitors of protein synthesis.In ouabain-treated cells neither levels of ATP nor transport of amino acids was limiting for protein synthesis. Loss of activity of messenger or other species of RNA was not responsible for inhibition of protein synthesis, since in the presence of actinomycin D, the rate of protein synthesis could be decreased or increased solely by adjusting cell K⁺. Release from ouabain inhibition restored K⁺ levels, macromolecular synthesis, and cell growth, but there was no resulting synchrony of cell division. In cell populations partially synchronized by serum starvation and refeeding protein synthesis was sensitive to reduction in K⁺ levels throughout the cell cycle.Our quantitative results show that cell K⁺ levels, when sufficiently reduced, can determine the rate of protein synthesis and hence the rate of cell growth.     

Phosphatase activity of blood leukocytes and wound exudate during the experimental healing of an aseptic wound

Cytochemical investigations of plain aseptic wounds simulated in 110 Wistar rats revealed a clear-cut dependence between the variations in the activity of alkaline and acid phosphatases in neutrophilic leukocytes, monocytes and lymphocytes of the blood and wound exudate and the stage of the healing process. Elevated activity of the blood alkaline phosphatase correlated with the term of inflammation phase.     

The effect of chalone on the cell cycle in the epidermis during wound healing

A cut was made on the ear conch of mouse and an extract containing epidermal chalone was injected subcutaneously 2 days later. The time changes after the chalone administration in the number of cells labeled with ³H-thymidine, in the number of grains on labeled cells and in the number of mitoses within the regenerating epidermis surrounding the wound were investigated by means of autoradiography (ARG). Grain counts decreased temporarily in early phase (0–2 h) after chalone injection. This decrease in grain count resulted in a decrease in the number of labeled cells on the ARG of a short exposure but not in that on the ARG of a long exposure. A decrease in the number of labeled cells on the ARG of a long exposure was evident at 6 h when the grain counts reverted to a level similar to the control without chalone. The number of mitoses reached a minimum at 2 h and then recovered quickly, indicating a rapid disappearance of the inhibition of cells in G 2 from entering M phase. Mitoses decreased again thereafter, presumably as a result caused by inhibition of cells in the preceding S phase from completing DNA synthesis. The extract made similarly from liver or kidney affected neither the mitotic nor the DNA synthetic activities.These results indicate that the epidermal chalone or chalones inhibit the epidermal cell proliferation in, at least, 3 different processes of the cell cycle; the DNA synthesis in S phase, the transition from G 1 to S phase and the transition from G 2 to M phase.     

Nicotine and its effect on wound healing

Our data demonstrate that nicotine impairs wound contraction in the rabbit ear model from the 4th to the 10th day of wound healing. However, the wounds contracted at essentially the same rate from the 12th to the 20th day in the experimental and control groups of animals. This study would suggest that cigarette smoking, with its associated nicotine ingestion, is adverse for a time to wound healing. It is clearly possible that in cases of extremity injury, or surgery, cigarette smoking may adversely affect wound healing.     

Cytophotometric evaluation of alkaline phosphatase activity in neutrophilic granulocytes and fibroblasts during wound healing in rats

The most informative indexes of alkaline phosphatase activity in neutrophil granulocytes from the peripheral blood and in neutrophil granulocytes and fibroblasts from the wound were defined in the experimental study carried out on 60 rats. These indexes were used to reveal the relationship between blood system reactions and inflammatory and regeneration processes in the wound tissue. The division of neutrophil granulocytes into three functional groups in accordance with alkaline phosphatase activity was demonstrated to be reasonable. The progress of inflammatory and regeneration processes in the wound tissues was shown to be adequately reflected in changes of both general and relative number of blood circulating neutrophil granulocytes of the third functional group characterized by high alkaline phosphatase activity. The results of the study demonstrate that the cytophotometric method is highly informative. It can be used in the clinical practice for an objective evaluation of the wound healing process as well as for an estimation of the treatment efficacy.     

The effect of canavanine on protein synthesis and protein degradation in IMR-90 fibroblasts

Proteins of IMR-90 fibroblasts incorporating [³⁵S]methionine during a 1 h labelling period in the presence of the arginine analogue canavanine were degraded twice as rapidly in the cells as were proteins similarly made in the presence of arginine. Using both isoelectric focusing and SDS-polyacrylamide gel electrophoretic analyses, the banding patterns of proteins labelled in the presence of canavanine and arginine were found to differ. This banding difference was detected as early as 15 min after canavanine treatment. With the exception of one minor band in isoelectric focusing gel, the relative intensity of labelled protein bands for the control samples remained unchanged during the 2 h period of protein degradation being investigated. This was also true for the proteins labelled in the presence of canavanine, despite the increase in their rate of degradation. Banding difference between canavanine and arginine treatment was also detected in an in vitro reticulocyte lysate translation system dependent on fibroblast mRNA. Proteins labelled in the presence of a different analogue, p-fluorophenylalanine instead of phenylalanine, however, had similar banding patterns as the control both in the lysate system and in intact cells.     

Effect of cyclic guanidine monophosphate on experimental wound healing

Studies on the effect of cGMP on the proliferation of granulation tissue and collagenogenesis in experimental wound healing have shown that cGMP promoted more rapid formation and differentiation of fibroblasts rose thereby promoting an accelerated formation of collagen. Histological and biochemical findings correlated with wound planimetry data. In the course of stimulation the wound healing surfaces diminished more quickly as compared to the control.     

Structure of the liver after correction of experimental chronic hepatitis with benzonal and potassium orotate

As a result of the experimental investigation of the liver damaged with CCL4, its essential structural changes have been revealed. They resemble those specific for a chronic toxic hepatitis. Administration of potassium orothate (100 mg/kg) increases proliferative activity of hepatocytes without any essential influence on intracellular regeneration. Under conditions of a delayed differentiation and lack of resorption of an abundantly outgrowing connective tissue, this results in a more profound pathological process in the liver. Benzonal administration (50 mg/kg) facilitates structural normalization of the chronically damaged liver, owing to activation of both cellular and intracellular regeneration.     

Time course and localization of DNA synthesis during wound healing of potato tuber tissue

DNA synthesis is induced in potato tuber tissue by wounding and starts after a lag period of about 8 hr. As demonstrated by the incorporation of labeled precursors, it reaches its peak between 14 and 18 hr after cutting, and returns to the initial low level before 24 hr, the time of first cell divisions. DNA synthesis is confined to those 2 or 3 cell layers below the wound, where cell division and starch degradation are observed later. Protein synthesis and increase in respiration extend much deeper into the tissue. Both the time course of DNA synthesis and its spatial distribution show patterns different from those of other wound-induced metabolic activities. As wound healing in potato tuber tissue involves the establishment of specific patterns with respect to the time course of induced metabolic activities as well as their spatial distribution, it should be considered and studied as a developmental process. The practical advantages of the system are discussed.