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Query: HUMANGGP:031673 (collagen)
 124,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adult rat parenchymal hepatocytes can be maintained in primary culture on floating collagen membranes of prolonged periods of time. In this system the enzyme tyrosine aminotransferase is induced by glucagon, (10(-6) to 10(-8) M) hydrocortisone (10(-5) to 10(-8) M), and cyclic adenosine 3':5'-monophosphate (cAMP) (10(-4) to 10(-5) M). Epinephrine (10(-4) M) induces the enzyme only in the presence of hydrocortisone. Addition of actinomycin D inhibited the induction of tyrosine aminotransferase by hydrocortisone and cAMP. Maintenance of the cultured hepatocytes in the presence of glucose (3g/liter) results in partial suppression of the inducing effects of glucagon and cAMP. Cyclic quanosine 3':5'-monophosphate does not mimic the effects of glucose. These results demonstrate that the phenomenon of glucose repression of enzyme induction, demonstrated in vivo in mammalian liver, is independent of changes in levels of serum hormones, which occur in vivo as a result of glucose administration. This study also demonstrates that glucose repression is not mediated by changes in intracellular levels of cAMP and cyclic quanosine 3':5'-monophosphate.
Cancer Res 1978 Jun
PMID:Hormonal regulation and the effects of glucose on tyrosine aminotransferase activity in adult rat hepatocytes cultured on floating collagen membranes. 2 9

A specific collagenase (EC 3.4.24.3) has been found and purified from serum-free culture medium of 11095 epidermoid carcinoma of rat prostate. The molecular weight of this collagenase was estimated at 71 000 and the pH optimum was approx. 7. At 26 degrees C, the collagenase cleaved collagen at a site 3/4 the length from the N-terminus. At 37 degrees C, this collagenase degraded collagen to smaller peptides. The enzyme activity was inhibited by serum, cysteine and EDTA, but not by protease inhibitors. The presence of collagenase in rat tumor tissue suggests that this enzyme might play a significant role in tissue invasion by cancer cells.
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PMID:Collagenase activity in cultures of rat prostate carcinoma. 3 9

Bleomycin treatment produced dose-dependent changes in lung collagen content and in several measurable histopathological parameters. NIH/Swiss mice were treated twice weekly for 6 weeks with bleomycin, 0, 1, 20, or 40 mg/kg s.c. The two highest doses produced mortalities of 35 and 100%, respectively, as well as loss of body weight and increase in lung wet weight. Lung hydroxyproline content, an index of collagen, increased to 40 to 50% above control levels at 6 and 8 weeks after initiation of treatment with bleomycin 20 mg/kg. Morphometric analysis was applied to the following parameters at light microscopy: number of intraalveolar macrophages and leukocytes, total pulmonary cell count, alveolar wall thickness, and percentage of consolidation of lung parenchyma. The two highest doses produced increases in all of these parameters as compared to controls. The most marked changes occurred in the number of intraalveolar cells, which in the group given 20 mg/kg rose to 150, 190, and 210% of controls at 4, 6, and 8 weeks. The lowest dose of bleomycin, 1 mg/kg twice weekly for 6 weeks, evoked no pulmonary or other toxicity by the parameters examined. This model of chronic pulmonary toxicity may be useful in analog development, in testing potential antidotes, and in examining the effects of other factors that might modify the pulmonary toxicity of bleomycin.
Cancer Res 1978 Mar
PMID:Quantification of bleomycin pulmonary toxicity in mice by changes in lung hydroxyproline content and morphometric histopathology. 7 60

The effects of three different dosage schedules on both therapeutic effect and pulmonary toxicity of bleomycin were studied in mice. Therapy was assessed by both survival and decreased tumor size in mice bearing Lewis lung carcinoma. Lung toxicity was estimated in nontumored mice as increases in lung collagen content by measuring lung hydroxyproline concentrations. In the first set of experiments, bleomycin injections twice daily (low-dose, high-frequency) produced a significant (34%) increase in lifespan over controls, whereas the same total dose given twice weekly did not result in increased survival. Both schedules produced pulmonary toxicity. Continuous sc infusion of bleomycin via an osmotic minipump was compared to these two schedules of intermittent injection. Identical total doses of drug were administered in all three schedules. Continuous infusion for 7 days produced marked inhibition of tumor growth (T/C = 16%), which was significantly better than twice weekly or ten-times weekly injection of the same total dose. Furthermore, at a total dose of 40 mg/kg of bleomycin, continuous infusion did not result in measurable pulmonary toxicity, whereas both schedules of bolus injection produced significant increases in lung collagen content. Thus, continuous infusion of bleomycin improved its therapeutic effect against Lewis lung carcinoma and also reduced its pulmonary toxicity.
Cancer Treat Rep 1978 Dec
PMID:Improved therapeutic index of bleomycin when administered by continuous infusion in mice. 8 69

Tw osteosarcomas of jaw bones have been studied by electron microscopy. The objectives were to examine the specific cell types in relation to functions and ultrastructural features, and to examine matrices produced by tumor cells. The osteosarcoma cells were subdivided into four cell types: anaplastic, chondroblastic, osteoblastic, and osteocytic--giant cells were not considered in the present investigation. Compared to normal bone cells, no specific sign of malignancy was found. However, tumor cells seem to lose functional abilities, i.e. a modification of matrix. Consequently, tumor matrix has altered organic and inorganic components with impairment of collagen maturation and matrix mineralization. The alteration in both processes may be related to a diminished production of proteoglycans. The cytogenic hypothesis of a tumor stem cell may be supported by the identification of anaplastic osteosarcoma cells resembling immature reticulum cells. One may speculate on transformation of this cell type as a genetically predetermined osteoprogenitor cell of malignant potential.
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PMID:Ultrastructural study of tumor cell differentiation in osteosarcoma of jaw bones. 9 36

Lesions of the lip seen over a 7-year period at a central laboratory serving the Igbos of Nigeria are reviewed. In approximately 8,500 surgical specimens, there were 63 jaw tumors but only 16 lip lesions. Two of lip lesions alone were carcinomas. Both were (a) squamous celled, (b) associated with sunlight-induced degeneration of the dermal collagen, and (c) found in young adult albinos. Accordingly, albinism should be recognized as one of the etiologic factors in lip cancer. The appropriate preventive action is the wearing of wide-brim hats by albinos.
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PMID:Lip lesions in Nigerian Igbos. 9 62

Primary cultures of epidermal cells from newborn mouse skin have been established. These cultures proliferate and express typical epidermal functions for limited time in vitro. The cultured cells keratinize and exhibit strong reactivity with an epidermis specific membrane antiserum. These cells can be transformed with DMBA either in standard cultures or more easily in cultures using 3T3 feeder cells. Transformed cells have increased proliferation rate. They do not pile up or form multilayered cultures like normal counterparts. They also keratinize less. When transformed cells were grown in the air on collagen gels they formed irregular clumps with central (horn-pearl) keratinization whereas normal controls formed stratified structures. Transofmred cells exhibited reduced reactivity with tissue specific membrane antiserum. There was masking or rearrangement of tissue specific membrane antigens with simultaneous exposition of new fetal-like antigens. Their reactivity with histocompatibility antisera was only slightly reduced. Transformed cells had both numerical and structural chromosome aberrations. They grew in soft agar and they induced tumors upon transplantation in the convenient host. When transplanted as cultures (on collagen) or as suspensions into the host, transformed cells were able to form epithelial cell cords invading the underlying mesenchyme with histological aspect typical of carcinoma. Cell cultures derived from in vivo DMBA induced tumors behaved like in vitro transformed cells.
Bull Cancer 1978
PMID:Characteristics of chemically transformed mouse epidermal cells in vitro and in vivo. 10 84

The ultrastructural features of a juvenile ossifying fibroma of the maxilla are described. The stromal portion of the tumor was composed of osteoblasts and to a lesser extent of fibroblasts. The bone spicules were rimmed by osteoblasts and osteoclasts. Calcification was seen to occur along the collagen fiber matrix, corresponding to calcification of osteoid, and also in the form of intracellular and extracellular crystallization. The latter form of calcification corresponded to so-called psammoma-like bodies, and was considered characteristic of this subtype of ossifying fibroma.
Cancer 1978 Dec
PMID:Juvenile ossifying fibroma: an ultrastructural study. 10 13

Collagen synthesis is increased over three-fold in capsules surrounding dimethylbenzanthracene-induced rat breast tumors compared to the tumor parenchyma and over six-fold compared to normal breast connective tissue. Increased collagen synthesis is independent of the rate of tumor growth and final tumor size. Pretreatment of animals with beta-aminopropionitrile to inhibit collagen cross-linking caused an 82% decrease in tumor formation and a significant reduction in tumor volume (approximately 0.4 cu cm) compared to controls (approximately 10 cu cm). The four small tumors that did develop in the lathyritic animals had increased collagen synthesis in the interior tumor stroma and reduced collagen synthesis in the tumor capsule. These findings suggest that the collagenous capsule surrounding dimethylbenzanthracene tumors functions as a physical barrier to protect the tumor from the immune system of the host. The apparent antitumor effects of beta-aminopropionitrile may be due to immunopotentiation and/or cytotoxic actions of the drug.
Cancer Res 1979 Aug
PMID:Collagen synthesis in capsules surrounding dimethylbenzanthracene-induced rat breast tumors and the effect of pretreatment with beta-aminopropionitrile. 11 Apr 42

The mechanism of stroma-formation and rearrangement of the stroma was studied on 221 cases of cancer of the lung, stomach and mammary gland using histological, histochemical and electron-microscopy methods of investigation. It was established that multiplying epithelial elements of teh tumour induced proliferation of histiogenic and vascular fibroblasts, activating them. Active fibroblasts play a double role: they either produce fibres and interstitial matter of the tumorous stroma, or participate in desintegration of preceding and newly formed collagenous structures. The processes of stroma-formation comply with the conventional schemes of normal fibrillogenesis and rearrangement of the interstitial tissue. It was shown that fibroblasts of the tumour stroma was capable of phagocytosis of a mature collagen. It is supposed that in the course of the tumorous growth correlation between the parenchyma and stroma is maintained, the leading role being played by the epithelium.
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PMID:[Stroma formation in epithelial malignant tumors]. 12 65


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