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Results for “Granulation Tissue”

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PubMed2000

Induction of matrix metalloproteinases in keratinocytes by cholesteatoma debris and granulation tissue extracts.

Although it is generally accepted that destruction and remodeling of temporal bone associated with middle ear cholesteatoma is mainly caused by the action of osteoclasts, it has been shown that neutral collagenases also play a role in predigesting the osteoid layer and exposing the mineralized bone to osteoclastic activity. Here we show that gelatinase B (matrix metalloproteinase-9) is over-expressed in cholesteatoma compared to external ear canal skin (EACS). Expression of MMP-9 in cholesteatoma mainly occurs in suprabasal layers, and more rarely in basal layers of cholesteatoma epithelium, as well as in inflammatory cells of the perimatrix. We further analyzed the influence of cholesteatoma debris, cholesteatoma granulation tissue, and cholesteatoma components such as keratin, cholesterol and bacterial endotoxin on the expression of MMPs in EACS keratinocytes. We show that cholesteatoma debris and granulation tissue extract both induced the secretion of MMP-9 by EACS keratinocytes, while keratin. bacterial lipopolysaccharide (LPS) or cholesterol did not show any effect. We further performed co-incubation and immunoprecipitation experiments using neutralizing interleukin-1alpha, EGF, TGF-beta, TGF-alpha, interleukin-6 and TNF-alpha antibodies. Inhibition of MMP-9 up-regulation by debris or granulation tissue extract could be revealed with diverse cytokine antibodies. The results are discussed with regard to previously published studies.

Antibodies↗
PubMed1991

Chronic administration of growth hormone-releasing factor increases wound strength and collagen maturation in granulation tissue.

The effects of chronic administration of growth hormone-releasing factor (GRF) on wound healing were studied in rats. Cutaneous wound strength was measured by tensometry at 5, 10, and 14 days postwounding in rats implanted with a slow-release pellet which contained a compressed mixture of a fatty acid and [desamino Tyr1, D-Ala2, Ala15]hGRF(1-29)NH2 or the fatty acid alone. There was a significant increase in wound tensile strength in GRF-treated rats compared to controls at each measurement: Day 5, 130 +/- 12 vs 97 +/- 14 g; Day 10, 402 +/- 18 vs 280 +/- 11 g; Day 14, 830 +/- 17 vs 614 +/- 14 g (P less than 0.01 for each value). Granulation tissue obtained from subcutaneously implanted polyvinyl alcohol sponges encased in silicone tubing was also studied. The amount of collagen deposited in the granulation tissue was estimated by measuring the hydroxyproline (Hyp) content of sponges retrieved 5, 10, and 14 days postinsertion from GRF-treated and control rats. Hyp content (nmole/mg sponge) was similar in both treated and control animals at each measurement: Day 5, 1.7 +/- 0.2 vs 2.2 +/- 0.2; Day 10, 31.9 +/- 4.1 vs 26.7 + 0.4; and Day 14, 41.6 +/- 7.3 vs 38.5 +/- 4.4. Hyp/proline, Hyp/glycine, and glycine/total amino acid ratios, evaluated after 10 days, were also similar in both groups. Collagen from the granulation tissue of sponges retrieved after 14 days from treated and control rats was studied by electron microscopy (magnifications, 7,100 and 22,720).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Influence of granulation tissue, dental calculus and contaminated root cementum on periodontal wound healing. An experimental study in monkeys.

The rôle of gingival granulation tissue, dental calculus and contaminated root cementum in marginal periodontal formation of new attachment was studied experimentally after chemical conditioning of the root surfaces of premolars and molars in 8 monkeys. Each treatment procedure was carried out in 4 monkeys. The other 4 monkeys served as controls. A morphometrical method was used to evaluate the results. It was concluded that a significant amount of new attachment including formation of new adhering cementum will result only on chemically-conditioned cementum surfaces. Small amounts of calculus or granulation tissue left in situ do not seem to influence healing, provided the cementum is left intact after chemical cleansing.

Alveolar Process↗
PubMed1987

Hyaluronidase activity of rabbit skin wound granulation tissue fibroblasts.

The objective of this work was to identify and compare hyaluronidase activities of normal dermal and dermal wound granulation tissue fibroblasts. Direct evidence of the fibroblast as a source of tissue hyaluronidase was obtained. Fourth passage rabbit dermal fibroblasts were harvested on culture days 4, 8, 14, 18, and 22. Hyaluronidase activity and [35S]-sulfate- or [3H]-glucosamine-labeled glycosaminoglycans (GAGs) were monitored. Hyaluronidase assays were performed on medium and cellular fractions at the designated intervals. Enzyme activity of cellular fractions for both normal dermal and 14-day post-wound granulation tissue fibroblasts increased progressively through culture day 8. Thereafter (days 14-22), an eight-fold drop in cellular activity was coupled with cell death and emergence of hyaluronidase activity in medium fractions. Marked increases in degradation of secreted matrix components were concurrent with lysis-induced release of hyaluronidase. In this culture system, hyaluronidase activity was confined exclusively to cellular fractions and was released into the medium only under non-physiological conditions conducive to cellular death and lysis. Accordingly, this work suggests that previously reported skin wound hyaluronidases may be of fibroblastic origin and that susceptible GAGs are not degraded extracellularly, but, rather, must be internalized as a prerequisite to depolymerization.

Animals↗
PubMed1993

Granulation tissue concentrations of ofloxacin after oral administration in invasive external otitis.

Following the fourth dose of 400 mg orally administered ofloxacin, simultaneous external ear canal granulation tissue and serum ofloxacin concentrations were estimated in 15 patients with invasive external otitis. The granulation tissue concentration was 2.2 (range 1.17-4.34) times higher than the serum concentration and 3.73 (range 1.95-11.00) times higher than the MIC90 of ofloxacin against Pseudomonas aeruginosa.

Administration, Oral↗
PubMed2005

Modeling dermal granulation tissue with the linear fibroblast-populated collagen matrix: a comparison with the round matrix model.

BACKGROUND: Wound contraction typically is not symmetrical; for example, a square-shaped wound will not yield a square scar. Interestingly, the round fibroblast-populated collagen matrix has been used as a model of wound contraction, even though contraction in this model is mostly symmetrical. OBJECTIVE: We wanted to compare the round versus linear fibroblast-populated collagen matrix to see which would be a better model of dermal granulation tissue. METHODS: Gross and microscopic morphology, contraction kinetics, cytoskeletal architecture, and apoptotic and proliferative indices were compared between the round versus the linear fibroblast-populated collagen matrix. A rat excisional wound model was used as an in vivo standard of healing. RESULTS: The rate of contraction was similar between the two models, although the mode of contraction was grossly asymmetric in the linear while remaining symmetric in the round model. Cellular survival and proliferation were both dependent on matrix attachment in both models; this was analogous to the attachment-dependence of granulation tissue. In the attached (restrained) condition, the level of cellular organization was higher in the linear than in the round matrix; the tissue architecture of the linear matrix, moreover, mimicked that of the excisional wound model. CONCLUSION: The round versus linear fibroblast-populated collagen matrix displayed a similar proliferative and survival response to matrix attachment. The latter model, however, demonstrated tissue organization with attachment and asymmetrical contraction after detachment analogous to that of the in vivo wound model. The linear fibroblast-populated collagen matrix appears to be the better model of dermal granulation tissue.

Apoptosis↗
PubMed1971

Contraction of granulation tissue in vitro: similarity to smooth muscle.

Strips of granulation tissue from three different experimental models contract in vitro when treated with substances that induce contraction of smooth muscle. Because the fibroblasts in such tissues have some ultrastructural features typical of smooth muscle, our findings indicate that fibroblasts are able to modulate toward a cell type that is morphologically and functionally close to smooth muscle.

Angiotensin II↗
PubMedDate not supplied

[Morphometric determination of changes in mastocyte population in cutaneous wound granulation tissue in hypothyroid and parotidectomized rats].

The authors have done a morphometric study by determination of mastocyte population of cutaneous wound's granulation tissue of parotidectomized rats and rats which were submitted to daily administration of 25 mg of 6-propyl-2-thiouracil (hypothyroid). The animals were sacrificed after four, eight and 12 post-operative days. The results analysis permitted to observe a statistically significant diminution of mastocyte population in the hypothyroid and parotidectomized animals granulation tissue in the fourth and 12th postsurgical days.

Animals↗
PubMed1981

Penetration of various mononuclear ribonucleases into rat experimental granulation-tissue fibroblasts and their intracellular effects.

The penetration of five different mononuclear ribonucleases into the subcellular particles of rat experimental granulation-tissue fibroblasts was compared, along with the effects of the enzymes on the fibroblast RNA fractions. Ribonucleases from normal and silica-treated rat peritoneal macrophages have been shown before to regulate the nucleic acid and protein metabolism of rat experimental granulation-tissue fibroblasts. These biologically active enzymes were taken into the fibroblasts in a greater amount than the corresponding human monocyte enzymes and the biologically inactive rat macrophage ribonuclease. The biologically active macrophage enzymes were incorporated mainly into the nuclear fraction. The other three mononuclear ribonucleases were not found particularly in any subcellular compartment. Both biologically active macrophage enzymes degraded the nuclear RNA of fibroblasts and released it to the soluble fraction in contrast to the biologically inactive macrophage enzyme and ribonuclease from normal human monocytes. Instead the ribonuclease from normal human monocytes seemed to degrade RNA in the soluble fraction. There were no marked differences in the subcellular effects of ribonucleases from normal and silica-treated macrophages. However, the treatment of human monocytes with silica changed their ribonuclease so that it split the nuclear RNA of fibroblast and released it to the soluble fraction in the same way as the biologically active macrophage enzymes did.

Animals↗
PubMed2005

Effect of a silicone-containing dressing on exuberant granulation tissue formation and wound repair in horses.

OBJECTIVE: To determine the effect of a silicone dressing on the rate and quality of repair of limb wounds and compare microvascular occlusion and apoptosis in wounds treated with the silicone dressing and those treated with a conventional dressing in horses. ANIMALS: 5 horses. PROCEDURE: Horses received two 6.25-cm2 wounds on each metacarpus. Ten wounds were treated with a silicone dressing; the other 10 were treated with a control dressing. Quality of repair and wound size were evaluated at each bandage change. Time to healing and the number of excisions of exuberant granulation tissue were recorded. Biopsy specimens taken from healed wounds were evaluated semiquantitatively via histologic examination, p53 immunohistochemical analysis, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) to quantify apoptosis, and electron microscopic examination to measure microvessel luminal diameters. RESULTS: The silicone dressing surpassed the conventional dressing in preventing formation of exuberant granulation tissue and improving tissue quality. Microvessels were occluded significantly more often in wounds dressed with the silicone gel, which also diminished the expression of mutant p53, an indirect inhibitor of apoptosis, although greater apoptosis was not confirmed quantitatively by use of TUNEL. CONCLUSIONS AND CLINICAL RELEVANCE: Because the silicone dressing inhibited the formation of exuberant granulation tissue, it may be integrated in a management strategy designed to improve the repair of limb wounds in horses.

Animals↗
PubMed1979

Glycoproteins from experimental granulation tissue and their effects on collagen synthesis in embryonic chick tendon cells.

Buffer-soluble and pronase-liberated glycoproteins from experimental granulation tissue were fractionated by gel filtration and DEAE-cellulose chromatography. The age of the granuloma was reflected in the gel filtration pattern. Two glycoproteins were isolated, purified to homogeneity and analyzed for their carbohydrate and amino acid compositions. The collagen synthesis in embryonic chick tendon cells was measured in the presence of these fractions, which were found to be inhibiting even at 10(-6) M. These glycoproteins may be significant in the feedback regulation of the development of granulation tissue and fibrosis.

Amino Acids↗
PubMed1990

Effects of cimetidine and omeprazole on angiogenesis in granulation tissue of acetic acid-induced gastric ulcers in rats.

We investigated the effects of cimetidine and omeprazole on angiogenesis in granulation tissue and on the healing of gastric ulcers induced by acetic acid in rats. Either cimetidine (50 or 100 mg/kg) or omeprazole (10 or 20 mg/kg) was orally administered once daily for 9 consecutive days from the day following ulcer production. The ulcer index on the 10th and 30th days after ulcer production, and the extent of angiogenesis on the 10th day were examined. Cimetidine dose-dependently decreased the extent of angiogenesis on the 10th day, whereas the ulcer index on the 10th days was not significantly different between cimetidine-treated and control rats. The ulcer index of the groups treated with cimetidine during the initial 9-day period was increased compared with the control group on the 30th day. In contrast, oral omeprazole did not affect angiogenesis on the 10th day and decreased the ulcer index on both the 10th and 30th days. These results suggest that oral cimetidine may inhibit angiogenesis in ulcer granulation tissue possibly via the blocking of histamine H2 receptors and this may be one cause of delayed ulcer healing.

Acetates↗
PubMed1999

The effect of pentadecapeptide BPC 157, H2-blockers, omeprazole and sucralfate on new vessels and new granulation tissue formation.

A clear protection of the gastrointestinal tract and an evident anti-inflammatory effect were shown for a novel stomach pentadecapeptide BPC 157 (i.p./i.g.) in comparison with several reference standards in various ulcer models along with a protection of endothelium and particular interaction with the NO-system. Thus, we evaluated whether this pentadecapeptide along with other gastroprotective agents could affect angiogenesis and the healing process in vivo using a procedure initially described by Szabo and co-workers. In each rat, two sterile sponges (1 x 1 x 0.25 cm; V = 0.25 mL) with the same quantities of BPC 157 (10 ng x mL(-1), 10 microg x mL(-1), 50 microg x kg(-1)) or reference agents (cimetidine: 10, 100, 500 mg x mL(-1); ranitidine: 2.5, 25, 250 mg x mL(-1); famotidine: 10, 50, 100 mg x mL(-1); omeprazole: 10, 50, 100 mg x mL(-1); sucralfate: 1, 5, 10 mg x mL(-1) were implanted subcutaneously in the lumbar region. The sponges were removed after 3 or 7 d, fixed in formalin, and processed for histologic and histochemical evaluation and morphometry assessment. Compared with the control values, the number of newly formed endothelial spaces inside newly formed granulation tissue was markedly increased in all animals treated with BPC 157, cimetidine, ranitidine, famotidine, sucralfate and omeprazole, a consistent finding noted after either 3 or 7 d. Compared with control values, markedly more granulation tissue was noted in the rats in the groups of animals treated with BPC 157 (50 microg) and in the rats treated with sucralfate in all dosages used, euthanized after 3 d. In all groups treated with H2-blockers however, similar values to those of controls were noted. Thus, it could be concluded that an evident angiogenic property was consistently noted for the novel pentadecapeptide BPC 157, H2-blockers (cimetidine, famotidine and ranitidine) and omeprazole, besides the well known angiogenic effect of sucralfate. Furthermore, unlike H2-blockers and omeprazole, BPC 157 stimulates the formation of granulation tissue, suggesting a particular activity, similar to that previously noted for sucralfate.

Animals↗
PubMed1981

Lack of influence on collagen accumulation in granulation tissue with 'delayed' defibrinogenation. A study in the rabbit.

Systemic defibrinogenation using Arvin delays wound strength development and collagen accumulation in sponge-induced granulation tissue. Whether this effect is due to interference with the initial fibrin deposition or to any inhibiting action on fibroblast function has not been decided. In the present study the administration of Arvin is started after the initial formation of a fibrin framework. No effect on collagen accumulation in granulation tissue was demonstrated, suggesting that the action of Arvin on wound healing is limited to the first phase of wound healing and that a normal fibrin deposition is necessary for a normal healing process.

Animals↗
PubMed1988

Evidence for the nonmuscle nature of the "myofibroblast" of granulation tissue and hypertropic scar. An immunofluorescence study.

Contraction is an important phenomenon in wound repair and hypertrophic scarring. Studies indicate that wound contraction involves a specialized cell known as the myofibroblast, which has morphologic characteristics of both smooth muscle and fibroblastic cells. In order to better characterize the myofibroblast, the authors have examined its cytoskeleton and surrounding extracellular matrix (ECM) in human burn granulation tissue, human hypertrophic scar, and rat granulation tissue by indirect immunofluorescence. Primary antibodies used in this study were directed against 1) smooth muscle myosin and 2) nonmuscle myosin, components of the cytoskeleton in smooth muscle and nonmuscle cells, respectively, and 3) laminin and 4) fibronectin, extracellular glycoproteins mediating cell-matrix attachment in smooth muscle and nonmuscle cells, respectively. Myofibroblasts can be identified by their intense staining of actin bundles with either anti-actin antibody or NBD-phallacidin. Myofibroblasts in all tissues stained for nonmuscle but not smooth muscle myosin. In addition, nonmuscle myosin was localized as intracellular fibrils, which suggests their similarity to stress fibers in cultured fibroblasts. The ECM around myofibroblasts stains intensely for fibronectin but lacks laminin, which suggests that a true basal lamina is not present. The immunocytochemical findings suggest that the myofibroblast is a specialized nonmuscle type of cell, not a smooth muscle cell.

Actins↗
PubMed2001

Mechanical tension controls granulation tissue contractile activity and myofibroblast differentiation.

We have examined the role of mechanical tension in myofibroblast differentiation using two in vivo rat models. In the first model, granulation tissue was subjected to an increase in mechanical tension by splinting a full-thickness wound with a plastic frame. Myofibroblast features, such as stress fiber formation, expression of ED-A fibronectin and alpha-smooth muscle actin (alpha-SMA) appeared earlier in splinted than in unsplinted wounds. Myofibroblast marker expression decreased in control wounds starting at 10 days after wounding as expected, but persisted in splinted wounds. In the second model, granuloma pouches were induced by subcutaneous croton oil injection; pouches were either left intact or released from tension by evacuation of the exudate at 14 days. The expression of myofibroblast markers was reduced after tension release in the following sequence: F-actin (2 days), alpha-SMA (3 days), and ED-A fibronectin (5 days); cell density was not affected. In both models, isometric contraction of tissue strips was measured after stimulation with smooth muscle agonists. Contractility correlated always with the level of alpha-SMA expression, being high when granulation tissue had been subjected to tension and low when it had been relaxed. Our results support the assumption that mechanical tension is crucial for myofibroblast modulation and for the maintenance of their contractile activity.

Actins↗
PubMed1981

Comparison of the effects of methylprednisolone and hydrocortisone on granulation tissue development. An experimental study in rat.

The effects of systemically administered methylprednisolone and hydrocortisone on granulation tissue development were compared using viscose cellulose sponges as wound model in the rat. The ingrown new tissue was analysed for the contents of various connective tissue components. The body weight gain of the animals was affected in both of the corticosteroid-treated groups. Hydrocortisone treatment decreased the contents of collagen, DNA and RNA and inhibited the development of vascularity especially in the initial phase of granulation tissue development. Methylprednisolone treatment decreased the content of collagen throughout the observation time of 3 weeks. It also decreased the content of RNA initially but the content of DNA and the development of vascularity were not affected until after 2 weeks' treatment. These results indicate that both of these corticosteroids affect the cells migrating into the sponge implant in the initial inflammatory phase, hydrocortisone more the number and methylprednisolone more the function of the cells.

Animals↗
PubMed2006

[Evaluation of intensity of angiogenesis in granulation tissue in chronic otitis media--preliminary report].

In chronic otitis media molecular pathogenetic mechanisms are still unknown, however, angiogenesis may play a role. The aim of the study was to determine the intensity of angiogenesis in granulation tissue in chronic otitis media of different clinical course. Twenty six granulation tissue specimens (twenty two--from chronic otitis media, four--from prolongated otitis externa) taken during surgery were analyzed. The angiogenesis (microvessel density) was measured in paraffin-embedded tissue by an immunohistochemical method, by staining for endothelial cells with a monoclonal antibody against CD 34. The presence of CD 34 was found in all specimens. The expression was more intense in tissue samples from the group with good clinical course (good healing and without recurrence) than those in the group with poor healing and recurrence (mean number of dots for mm2 589,2 vs 533,3, respectively) and from the group without bacterial infection by Pseudomonas aeruginosa than those with this infection (mean number of dots for mm2 645,5 vs 440,8, respectively), but differences were not significant. In conclusion it is suggested that angiogenesis may contribute to different clinical course of chronic otitis media.

Adult↗