Effects of tumor promoters and steroidal anti-inflammatory agents on skin of newborn mice in vivo and in vitro.
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Animals↗
Biomedical subjects
K Elgjo
Publications and source records attributed to K Elgjo.
Relative value of sternal aspiration, iliac crest biopsy and biopsy imprint in the diagnosis of secondary cancer involvement of the bone marrow.
Sternal aspirates, iliac crest biopsies and biopsy imprints from 31 patients with verified metastatic cancer to bone marrow were reviewed. All three methods were shown to be complementary, as cancer cell deposits were detected in some cases by one procedure and missed by the others.
Biopsy↗
Peroperative endoscopic diagnosis of small intestinal bleeding.
Two patients with recurrent bleeding from vascular anomalies in the small intestine are described. In both patients intestinal angiography had shown either pathological vessels or extravasation of blood into the proximal part of jejunum, but during explorative laparotomy the source of bleeding had not been found. The diagnosis was made by performing peroperative endoscopy. After resection of the involved small bowel segment one patient with cavernous hemangioma has remained asymptomatic. In the other patient, who suffered from a combination of multiple arteriovenous malformations and a congenital platelet defect, limited surgical resection did not influence the need of blood transfusions. This investigational approach should become the method of choice in patients suspected of bleeding from the small intestine.
Aged↗
Quantification of gastrin-producing cells (G cells) and parietal cells in relation to histopathological alterations in resected stomachs from patients with peptic ulcer disease.
The distribution and numbers of G cells and of parietal cells were related to the distribution and severity of histopathological alterations (inflammatory cell infiltration, atrophy and intestinal metaplasia) in corresponding mucosal tissue blocks from resected stomachs (12 patients with gastric ulcer, 11 with duodenal ulcer, and 14 with duodenal ulcer and uremia). In all patients the histopathological features were more severe in the pyloric antrum than in the body, and the change in severity corresponded well with the disapperance of G cells at the body-antrum border. The transitional body-antrum zone was histopathologically similar to the remaining antrum. A marked individual heterogeneity of the histopathological alterations was observed. An increasing grade of atrophy was associated with increased severity of inflammation, and the presence of intestinal metaplasia was especially associated with atrophy. No significant correlation was found between the antral G-cell number and the grade of antral inflammatory cell infiltration, whereas there was a reduction in cell number with increasing grade of atrophy in all patient categories. The parietal-cell density in the body mucosa was decreased with increasing grade of inflammation as well as with increasing grade of atrophy. The presence of patchy intestinal metaplasia resulted in a complete absence of G cells and of parietal cells from the corresponding part of the mucosa in the antrum and body respectively.
Adult↗
Partial purification of epidermal G2 chalone.
A partial purification of epidermal G2 chalone from crude epidermal cell extracts from hairless mice is described. The procedure involved the sequential use of ammonium sulphate precipitation, affinity chromatography and gel filtration. Mitosis-inhibiting activity at each stage in the purification was tested in an in vitro assay system employing human epidermoid carcinoma cells in exponential growth phase and Colcemid (Ciba) for arresting mitoses. This assay system is much more rapid and convenient than conventional in vivo systems. By the procedure described, a 10,000-fold material purification of the active component has been obtained. This corresponds to a 3,000-fold purification measured by protein content, and a 300-fold increase in mitosis-inhibiting activity per unit we;ght. The active component is acidic, contains sugar residues and has gel chromatographic properties characteristic of a substance with molecular weight of approximately 20,000. On SDS polyacrylamide gel electrophoresis, however, three weak bands were found. The active component is resistant to trypsin and protease and stable between pH 6.0 and 8.5. It is easily inactivated at pH values below 6.0. At the present stage of purification, several components other than the active one still remain in our material and further purification steps must be eventually employed.
Animals↗
Growth kinetics in newborn mouse epidermis: response to epidermal chalone.
Epidermal DNA synthesis, the epidermal mitotic rate, and the responsiveness to the epidermal G1 and G2 inhibitors were examined in newborn mice at different times after birth. The rate of epidermal cell renewal was in general low during the first two weeks of life. Later the two growth parameters increased and reached very high values at 32-33 days after birth. The rate of epidermal cell proliferation then decreased to a level comparable with that found in adult hairless mouse epidermis at 40-45 days. A single i.p. injection of skin extract containing the two epidermal growth inhibitors induced varying types of responses. The epidermal G2 inhibitor stimulated the mitotic rate on day 2 and day 10, but inhibited it on all other days. The epidermal G1 inhibitor brought about an increase in epidermal DNA synthesis on day 6 and possibly on the following days. No response at all seen at 2, 4, 17, and 32 days after birth. At the other examined times the inhibition was similar to that found in adult mice. These findings differed from those made in vitro on separated newborn mouse epidermal cells (our own unpublished data), and we suggest that the variability of newborn mouse epidermis could be an expression of the immaturity of the skin as a whole, and that dermis in some way modifies the response of epidermis to exogenous epidermal chalone. Our study did not support the theory that the nonresponsiveness of newborn mouse epidermal at certain times could be due to the presence of nonresponsive stem cells in epidermis.
Aging↗
Retinyl acetate modulation of cell growth kinetics and carcinogen--cellular interaction in mouse epidermal cell cultures.
Exposure of mouse epidermal cell cultures to beta-retinyl acetate (RA) affects a number of parameters presumed to be important in chemical carcinogenesis. (1) RA alters the course of differentiation of the epidermal cells in culture resulting in a reduced rate of cell death which normally follows cellular maturation during the first two weeks in culture. The extended life span of the cultures appeared due to prolonged survival of cells and not to increased growth rate since RA inhibited the rate of cellular proliferation. This inhibition took place only after completion of a full cell cycle in the presence of RA. (2) DNA repair in response to physical and chemical agents was quantitatively unaffected in the presence of RA. (3) The activity of constitutive aryl hydrocarbon hydroxylase (AHH) was slightly decreased after exposure to RA but the level of enzyme induced by benz[a]anthracene was strongly reduced to 20% of the controls. (4) In the presence of RA, binding of 7,12-dimethylbenz[a]anthracene to epidermal cell DNA was markedly decreased. In contrast, binding to cellular protein was significantly increased by the retinoid.
Animals↗
Morphology of mouse epidermal cells in vitro: a scanning electron microscopy study.
Scanning electron microscopy of isolated epidermal cells from newborn mice grown in vitro showed that the cultures consisted of several morphologically different types of cells. Young cultures had many smooth, round cells while older cultures contained more cells with rough or ruffled surface and a varying number of flat, irregular cells. Probably, the various cell types corresponded to different stages of differentation (keratinization). Cultures that were grown in the presence of retinyl acetate (12.5 microgram/ml) had more round and smooth cells after several days in vitro than the controls. This could indicate that retinyl acetate delayed or altered cell differentiation. Scanning electron microscopy of the cultures consistently showed that the cells were situated at different layers. The apparent monolayer seen by phase contrast microscopy therefore seems to be an optical phenomenon due to projection of the cells onto the same plane.
Animals↗
Effects of bleomycin on the epidermal content of growth-regulatory substances (chalones).
Hairless male mice were given 2 mg Bleomycin i.p. on two successive days. At different time intervals from 1 to 10 days after the last Bleomycin injection, groups of animals were killed and water extracts of hemogenized skin were made. These extracts, supposed to contain the epidermal G1 and G2 chalones, were injected into female hairless mice, and their growth inhibitory potency determined by two methods. 5 mg of lyophilized crude skin extract were injected i.p. together with Colcemid, and the animals killed 4 hr later. The number of Colcemid-arrested mitoses was determined, and was considered to be a measure of the G2 inhibitor present in the skin extracts. 10 mg of the same extracts were injected i.p., and these animals also got 3H-TdR i.p. 12 hr later, and were killed after a subsequent 30 min. The epidermal LI was determined, and was considered to be a measure of the epidermal G1 factor in the skin extracts. The results obtained were compared to the effect of Bleomycin alone and to the effects of skin extracts from non-Bleomycin-treated animals. The results show that Bleomycin provoked slight alterations in the growth-inhibitory potency of the G1 chalone, whereas significant effects were seen in the G2 chalone, There was an increased amount of growth-inhibiting factors on days 2 and 3, and on days 8-10. The results are discussed and it is concluded that the most probable hypothesis is that Bleomycin, in addition to its known inhibition by accumulation of cells with high growth inhibitory potency. An initial, additional direct effect of Bleomycin on the chalone system cammot be excluded.
Animals↗
Amyloidosis and Crohn's disease.
Amyloidosis associated with Crohn's disease was found in 7 patients among 85 subjected to intestinal resection for granulomatous enterocolitis. Most of the patients had symptoms of inflammatory bowel disease of relatively short duration before the diagnosis of amyloidosis was made and were without suppurative complications. Systemic involvement was seen in 6 of the patients. One died postoperatively from renal failure, and in 2 other patients kidney transplantation was performed because of deterioration of a pre-existent renal insufficiency. Six patients were alive 6 months to 10 years after amyloidosis was diagnosed. There is great risk of rapid deterioration of kidney function postoperatively in these patients. However, our experience suggests that in some cases the progression of amyloidosis may be delayed or even brought to a halt after surgical treatment of Crohn's disease.
Adolescent↗
Effects of croton oil on epidermal growth regulators (chalones).
Variations in epidermal chalones after a single surface application of methylcholanthrene have been described in previous papers. This paper reports a study of the effect of croton oil on epidermal growth regulators (G1 and G2 chalones). Hairless mice received a single topical application of 0.2 ml 0.25% acetone solution of croton oil. Control mice received only acetone. The short-term effect of croton oil on epidermal DNA synthesis and mitotic rate was studied. Other groups of croton oil-treated and acetone-treated mice were then killed at similar time intervals, and the treated area of skin was homogenized and extracted with water. The inhibitory effect of these extracts on normal epidermal DNA synthesis and mitotic rate was assayed in normal hairless mice. The resulting inhibition was interpreted as an expression of the concentration of G1 and G2 chalones, respectively, in the skin extracts. The first experiment confirmed that a single croton oil application provokes a short block in epidermal mitotic activity and probably also in DNA synthesis. This was followed by bimodal peaks of increased activity, the two maxima of mitotic rate on days 2 and 7. The concentration of the two chalones in the skins of treated animals varied in inverse proportion to the alterations in the DNA synthesis and the mitotic rate, with one exception. There was here initially a depression both of the mitotic rate and a low concentration of G2 chalone. This was interpreted as a short, initial direct effect of croton oil on the G2 chalone present at the time of application. It is concluded that croton oil application injures and kills epidermal cells, with subsequent alterations in the content of G1 and G2 chalones. This theory may explain the changes observed. The effects of croton oil on the amount of G1 and G2 chalones in the skin are probably related to the direct, toxic, cell-killing effect of croton oil, and not to its specific cancer promoting potency.
Animals↗
Classification of liver diseases by clinical chemical laboratory results and cluster analysis.
Patients with liver diseases were classified by cluster analysis using only clinical chemical laboratory results. A strong tendency towards correspondence between this classification, based on functional criteria, and the previous diagnoses, based mainly on liver biopsy findings, was found.
Acute Disease↗
Natural synchrony of newborn mouse epidermal cells in vitro.
Epidermal cells were separated from newborn mouse skin and grown on glass chamber slides or in plastic Petri dishes. Cell proliferation was examined at short intervals during the first 3 to 4 days in culture. DNA synthesis was estimated by the incorporation of [3H]thymidine into epidermal DNA, or by the labeling index. The mitotic rate was estimated by blocking mitotic cells with vinblastine. Reasonable agreement was found with the different methods. The cells grew synchronously with peaks of DNA synthesis at 21 to 23 hr, 35 to 40 hr, and 60 hr; peak mitotic rates were seen at 44 to 48 hr and 72 to 76 hr. The cells appeared to grow exponentially during the first 3 to 4 days in culture, with one main cohort of cells dividing during the successive proliferative peaks.
Animals↗
Effects of methylcholanthrene on epidermal growth regulators. II. Variations in the S-factor.
There is increasing evidence to support the existence of tissue-specific growth-inhibitory chemical substances which can be found in extract homogenized cells. In the epidermis, two such tissue-specific factors (which also have cell-cycle specificity) have been found. These factors act specifically on different phases of the cell cycle (epidermal G1 and G2 chalones, respectively). This paper concerns a study of the effect of 20-methylcholanthrene on the epidermal G1 chalone. The variations in epidermal G2 inhibitor after such treatment were described in a previous paper. Hairless mice received a single topical application of 0.2 ml 0.5% solution of the carcinogen. The short time effect of the carcinogen application on epidermal DNA synthesis was first studied. Other groups of carcinogen-treated mice were then killed at similar time intervals, and the treated area of skin was homogenized and extracted with water. The inhibitory effect of these extracts on normal epidermal G1 cells was assayed in normal hairless mice. The obtained inhibition was registered as an expression of G1 inhibitor concentration in the skin extracts. The first experiment confirmed that a single carcinogen application provokes a short block in epidermal DNA synthesis, followed by a high, biomodal peak of increased activity with the first and maximum peak on day 2, and a smaller peak on day 8 after treatment. The second experiment showed that the content of G1 chalone in the skins of treated animals varied inversely to the alterations in epidermal DNA synthesis, revealing almost no chalone activity on day 2, and reduced chalone activity on day 8.
Animals↗
Growth parameters of the hairless mouse epidermis after bleomycin treatment: possible interaction with epidermal chalones.
Hairless mice were given two injections of 2 mg bleomycin i.p. on two successive days. By a stathmokinetic method, micro-flow fluorometry and autoradiography, many kinetic parameters were measured. Bleomycin affected cell proliferation in epidermis by depressing the number of cells in and the passage of cells through the different cell cycle phases, i.e. S, G2 and M in a biphasic manner. The time between the two minima corresponded to the mean generation time of the basal cells. Skin extracts produced from animals at different time intervals after the bleomycin injection show that bleomycin interferred only slightly with the G1-chalone, but had a more pronounced effect on the content of G2 of the skin, increasing and reducing the chalone effect in a biphasic manner. The study gives some support to the theory that the particularly good effect of bleomycin in squamous cell epithelium may be due to an interference of bleomycin with keratinization and chalone production. The protein synthesis showed only a minimal depression where the kinetic parameters were heavily depressed.
Animals↗
Stimulated DNA synthesis in mouse epidermal cell cultures treated with 12-O-tetradecanoyl-phorbol-13-acetate.
Exposure of mouse epidermal cells in culture to 12-O-tetradecanoyl-phorobol-13-acetate (TPA) results in an initial inhibition of DNA synthesis for 24 hr followed by a 5- to 10-fold stimulation at 72 to 96 hr. A corresponding increase in mitotic rate also occurs at 72 to 96 hr. These responses occur when TPA is continuously present in the medium or if the exposure is as short as 1 hr, but the degree of stimulation was dependent on dose and duration of exposure. Sensitivity to TPA varied with the length of time the cells were in culture prior to treatment. TPA treatment also produced an alteration in morphology from clearly epithelial to a more fibroblastic type. These biochemical and morphological effects did not occur after treatment of epidermal cells with either phorbol-13,20-diacetate or phorbol. Primary dermal fibroblasts in culture did not respond to TPA in this manner, but a line of cultured liver epithelial cells was slightly stimulated by the promoter. This system appears to be a sensitive in vitro model for detecting the hyperplasia-inducing effects of phorbol esters and should be used for mechanistic studies and bioassay.
Animals↗
Polyinosinic-polycytidylic acid: inhibition of cell proliferation in carcinogen-treated epidermis and in carcinogen-induced skin tumors in mice.
After administration of the synthetic double-stranded RNA polyinosinic with polycytidylic acid (poly l with poly C) to hairless mice, cell proliferation kinetics were studied in normal epidermis, in epidermis initiated with 3-methylcholanthrene (MCA), in hyperplastic epidermis treated topically with MCA for 15 weeks, and in MCA-induced skin tumors. Poly l with poly C did not influence the mitotic rate or the transit of cells from the G1 phase to the S phase in normal mouse epidermis. Pretreatment of poly l with poly C inhibited cell proliferation in mouse epidermis initiated with MCA for at least 24 hours. In mouse epidermis made hyperplastic by repeated applications of MCA. Poly L with poly C inhibited G1 cells from starting DNA synthesis. Skin tumor DNA synthesis was also altered after poly l with poly C administration. After a short period of enhanced 3-methylthymidine incorporation, tumor DNA synthesis decreased to less than half the control value. The results indicated thatthe antitumorigenic effect of poly l with poly C could be related to its influence on cell proliferation.
Administration, Topical↗
Epidermal chalone and cyclic AMP: an in vivo study.
Water extracts of skin contain two factors that inhibit epidermal cell proliferation: one substance inhibits epidermal cells in the G2 phase (the epidermal G2 inhibitor), and another inhibits the transit of cells from the G1 phase into the S phase (the epidermal G1 inhibitor). Pretreatment of mice with a beta-receptor antagonist (propranolol) abolished the activity of the G2 inhibitor but not that of the G1 inhibitor. After pretreatment with both propranolol and a phosphodiesterase inhibitor (caffine)the G2 inhibitor had full effect. Cafine alone had a moderately inhibitory effect on epidermal G2 cells and enhanced the depressing effect of the G1 inhibitor on epidermal DNA synthesis. AMP level in epidermis to be active. Cyclic AMP is probably also involved in the regulation of the rate of transit of epidermal G1 cells into the S phase but the epidermal cyclic AMP level seems not to be so critical for the efficacy of the epidermal G2 inhibitor in epidermal cell differentiation.
Animals↗