"July, 2001" / Addendum inserted in back. / Includes bibliographical references (leaves 250-284) / xxiii, 284 leaves : ill. (some col.), plates (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Surgery, 2001

Introduction Keloids are formed by the excessive production of scar tissue, which extends beyond the margins of the original injury, often resulting in lesions of grotesque dimensions. Keloids present a major dilemma to surgeons because of the high recurrence rate with recurrent growth often larger than the original keloid. The high recurrence rate and the poor response of keloids to therapy present a great challenge to surgeons. The numerous therapeutic regimens demonstrate that to date there is no single therapy that is absolutely successful. Therefore, it is necessary to comprehensively establish the pathology of keloids and to determine the aetiopathogenesis of the lesion in order to eventually provide unfailing specific effective treatment and to better understand the mechanisms regulating fibrosis in various fibroproliferative diseases. Aim To evaluate the pathology and aetiopathogenesis of keloid formation. Methods The research protocol for the study was approved by the Nelson R Mandela Faculty of Medicine Ethics Committee. Informed consent was obtained before the biopsies were taken. Keloid and non-lesional skin biopsies were obtained from thirty two patients who had multiple lesions in various locations, bringing the total number of keloids and apparently normal skin biopsies processed and examined to fifty eight. The biopsied specimens were processed for paraffin wax embedment and routine haematoxylin and eosin, differential and immunocytochemical staining. Sections were scrupulously examined using the Olympus BH-2 microscope; features pertinent to the study were photographed with the Olympus DP 10 microscope digital camera system. The stored images were studied, using the Camedia graphics processing programme. Results The results of the study showed that keloids comprise many distinct regions categorized as: the zone of hyalinising collagen bundles, fine fibrous areas, areas of inflammation, zone of dense regular connective tissue, nodular fibrous area and area of angiogenesis. Fibroblastic phenotypes present ranged from spindle, fibrohistiocytic, epitheloid, elongated flattened condensed fibroblastic cells to few wavy, fuzzy, polygonal and atrophic cell types. Immunocytochemically these cells were vimentin-positive and actin- and desmin-negative. Few myofibroblastic phenotypes were also identified and these were vimentin- and alpha smooth muscle actin-positive and desmin-negative. The fibroblastic and myofibroblastic phenotypes were in proliferative or degenerative stages and pathological features exhibited were the presence of vesicular, degenerate or calcified nuclei; nuclear and plasma membrane damage; cytoplasmic and nucleoplasmic clearing; atrophy, pyknosis and swelling. Severe, moderate to mild paravascular inflammation was observed around the microvessels of the sub-papillary plexus and within the keloid. There was compression and occlusion of small blood vessels, coagulation necrosis and dissolution of mural cells of small blood vessels and small peripheral nerves. Also present in keloids were oedematous areas, disorganised and hyalinised connective tissue fibres and increased numbers of degranulated and degranulating mast cells. Elastic fibres in keloids were minimal or absent whereas at the border of keloids there was an increase.Discussion Degenerate, occluded and compressed microvessels were a widespread pathological feature in keloids. This resulted in impaired vascular supply to each of the keloid regions which impacted directly on the pathology of keloids where degeneration and necrosis, manifesting the lack of nutrients and oxygen to tissue, were found throughout the keloid. The vascular supply was impaired because of the chronic inflammatory destruction of the microvessels and the elevated stress within keloids. Factors contributing to increased intrinsic stress were: 1) the lack of elastic fibres in keloids which decreased the elastic limit, leading to effects of excessive deformational force which were compression and stiffening of tissue; 2) the high tension skin covering keloid prone areas had low stretch and a low elastic modulus; 3). protruding hard connective tissue such as bony prominences or cartilage into the dermis of keloid prone skin; 4) contractile forces exerted by wound healing fibroblastic cells; and 5) external forces. Compression and occlusion of blood vessels induced ischaemic and reperfusion tissue injury. During the reperfusion phase blood rich in growth factors returned to tissue stimulating tissue growth. Tissue growth was also promoted by elevated internal stress which stimulated increasing levels of gene expression, collagen synthesis and mitotic activity. All these growth promoting effects resulted in keloid formation. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.

Includes bibliography (leaves 191-219). Examines the levels of insulin-like growth factor and the presence of IGF binding proteins in human wound fluid. Tests the potency of IGF-1 and 2 analogues in in vitro models of fibroblast activity and their effect on healing in normal and diabetic rodent wounds. Shows that IGF-1, IGF-2 and their binding proteins are present in fluid from a partial thickness cutaneous wound; that the binding proteins negatively modulate the activity of insulin-like growth factors in vitro, but that the IGFs do not necessarily show enhanced activity in vivo at the wound site if binding protein affinity is decreased. Discusses possible roles of these binding proteins in wound repair.

Includes bibliography (leaves 191-219). / Copy 2 lacks some pages. / x, 219 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines the levels of insulin-like growth factor and the presence of IGF binding proteins in human wound fluid. Tests the potency of IGF-1 and 2 analogues in in vitro models of fibroblast activity and their effect on healing in normal and diabetic rodent wounds. Shows that IGF-1, IGF-2 and their binding proteins are present in fluid from a partial thickness cutaneous wound; that the binding proteins negatively modulate the activity of insulin-like growth factors in vitro, but that the IGFs do not necessarily show enhanced activity in vivo at the wound site if binding protein affinity is decreased. Discusses possible roles of these binding proteins in wound repair. / Thesis (M.D.)--Dept. of Surgery, University of Adelaide, 2001?

The effect of absorbable packing on the healing of nasal respiratory epthelium after endoscopic sinus surgery (ESS) was examined in a diseased sheep model. Full thickness injuries were created on the lateral nasal wall of sheep infested with Oestrus ovi. Sites of injury were packed on one side with hyaluronic acid (HA) packing or hyaluronic acid packing impregnated with insulin-like growth factor- 1 (HA+IGF1) in a randomized fashion. The opposite side was left unpacked as a control. Biopsies were obtained for light microscopy, scanning electron microscopy, and ciliary beat frequency (CBF) analysis over a period of 16 weeks. Statistical analysis of results was performed in order to determine if any intervention had any impact on healing and to determine if there was any correlation between extent of regeneration as assessed by electron microscopy and CBF. Furthermore assessment of the effect of isotonic and hypertonic saline on ciliary beat frequency was performed in healthy human volunteers. Reepithelialization was increased in the HA+IGF1 group compared to the HA group and controls at eight weeks after injury but not at later time points. Cilial regeneration was improved in the HA+IGF1 group compared to the HA group and controls at 16 weeks. CBF was noted to be worse at the eight week time point with the HA+IGF1 group compared to the HA group and controls, but no other statistically significant effects on CBF were noted. This most likely represents a spurious finding. Wide distributions of CBF results were noted, reflecting numerous missing data points due to methodological difficulties. There was a trend noted toward increased CBF with improved grades of reciliation, although this correlation was not statistically significant. However this trend was supported by the finding of statistically significant differences between individual and combined grades of reciliation. Hypertonic saline was found to have a ciliostimulatory effect when compared to normal saline at 5 minutes after administration in healthy human subjects. This effect had disappeared by 60 minutes after administration. It is suggested that the presence of insulin-like growth factor- 1 at the time of mucosal injury improves epithelial regeneration in the short term, but is not sufficient for this effect to be sustained. This improved early epithelial regeneration forms a foundation for cilial regeneration, as is reflected in an improved grade of reciliation at 16 weeks. Our interventions had no effect on CBF, and various experimental problems made it difficult to provide further comment on CBF results. There is evidence that CBF improves as the grade of cilial regeneration improves following ESS. Furthermore, hypertonic saline appears to also have a positive impact on CBF, which is likely to reflect changes in the rheological properties of mucous. A number of possible avenues of enquiry are delineated and recommendations for future research are outlined. / Thesis (M.S.)--Department of Surgery, 2005.

Two leaves of errata and addenda pasted into back pages. / Bibliography: leaves 174-208. / xix, 208 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis aimed to determine general roles for insulin-like growth factor binding proteins (IGFBPs) in regulating insulin-like growth factor-I (IGF-I) actions in wound repair. Preliminary experiments sought to characterise alterations to IGF-I levels and IGFBP profiles that may occur during wound repair. The effects that interactions with IGFBPs may have on IGF actions in wounds were addressed. Final experiments aimed to determine whether IGFBP-3 proteolysis observed in the initial work of the thesis acted to increase IGF bioavailablity. The results are discussed. / Thesis (Ph.D.)--University of Adelaide, Dept. of Surgery, 2000

The effect of absorbable packing on the healing of nasal respiratory epthelium after endoscopic sinus surgery (ESS) was examined in a diseased sheep model. Full thickness injuries were created on the lateral nasal wall of sheep infested with Oestrus ovi. Sites of injury were packed on one side with hyaluronic acid (HA) packing or hyaluronic acid packing impregnated with insulin-like growth factor- 1 (HA+IGF1) in a randomized fashion. The opposite side was left unpacked as a control. Biopsies were obtained for light microscopy, scanning electron microscopy, and ciliary beat frequency (CBF) analysis over a period of 16 weeks. Statistical analysis of results was performed in order to determine if any intervention had any impact on healing and to determine if there was any correlation between extent of regeneration as assessed by electron microscopy and CBF. Furthermore assessment of the effect of isotonic and hypertonic saline on ciliary beat frequency was performed in healthy human volunteers. Reepithelialization was increased in the HA+IGF1 group compared to the HA group and controls at eight weeks after injury but not at later time points. Cilial regeneration was improved in the HA+IGF1 group compared to the HA group and controls at 16 weeks. CBF was noted to be worse at the eight week time point with the HA+IGF1 group compared to the HA group and controls, but no other statistically significant effects on CBF were noted. This most likely represents a spurious finding. Wide distributions of CBF results were noted, reflecting numerous missing data points due to methodological difficulties. There was a trend noted toward increased CBF with improved grades of reciliation, although this correlation was not statistically significant. However this trend was supported by the finding of statistically significant differences between individual and combined grades of reciliation. Hypertonic saline was found to have a ciliostimulatory effect when compared to normal saline at 5 minutes after administration in healthy human subjects. This effect had disappeared by 60 minutes after administration. It is suggested that the presence of insulin-like growth factor- 1 at the time of mucosal injury improves epithelial regeneration in the short term, but is not sufficient for this effect to be sustained. This improved early epithelial regeneration forms a foundation for cilial regeneration, as is reflected in an improved grade of reciliation at 16 weeks. Our interventions had no effect on CBF, and various experimental problems made it difficult to provide further comment on CBF results. There is evidence that CBF improves as the grade of cilial regeneration improves following ESS. Furthermore, hypertonic saline appears to also have a positive impact on CBF, which is likely to reflect changes in the rheological properties of mucous. A number of possible avenues of enquiry are delineated and recommendations for future research are outlined. / Thesis (M.S.)--Department of Surgery, 2005.

Introduction: Endoscopic sinus surgery (ESS) is at present the gold standard therapeutic modality for chronic rhinosinusitis (CRS) resistant to medical therapy. Whilst results from ESS for CRS are generally good, postoperative bleeding and impaired wound healing with adhesion formation remains a concern. Due to patient discomfort and the detrimental effects on wound healing caused by most packing materials, many surgeons no longer routinely use nasal packing. Surgeons have in the past sought agents which would provide post-operative haemostasis without detrimentally affecting wound healing. Antifibrinolytics have been available for many years, however, their topical application has only been explored in the last few years. Recently different forms of chitosan have separately shown significant promise as powerful haemostatic and anti-adhesion agents. The aim of this thesis was to explore the progressive understanding of the interaction between haemostasis and wound healing with possible development of a novel agent. Methods: The first step to scientifically assess bleeding after sinus surgery was to develop a standardised method of video endoscopy and grading the surgical field during ESS. This was done as a multinational collaborative trial. Once this assessment tool was validated a randomised controlled trial evaluating the effect of two antifibrinolytics (epsilon aminocaproic acid and tranexamic acid) was conducted. Further evaluation was then conducted on other possible hemostatic and antiadhesion substances. This included various combinations of a novel chitosan gel. These gels were trialled in vitro to determine their effect on human nasal fibroblasts derived from CRS patients. Fibroblast adhesion and proliferation as well as closure of standardised wounds were studied. The most promising of these gels was then used in an in vivo sheep model. Once effectiveness of the chitosan-dextran gel was shown in the laboratory, this was evaluated against a number of currently available hemostatic and anti-adhesion substances in a standardised model of wound healing in sheep with CRS. This model had been previously extensively validated in our department. Full thickness mucosal injuries were created on the lateral nasal wall and ethmoids of twenty sheep and recombinant tissue factor (rTF), SprayGel or Chitosan-Dextran derivative gel applied topically in a randomized fashion. Adhesion formation and severity as well as microscopic wound healing and ciliary function were analysed at day 28, 56, 84 and 112 post initial surgery. A further sheep study was conducted applying chitosan dextran gel to standardised mucosal injuries and comparing its effect on the control of bleeding to control. Bleeding time and grade were recorded and wound healing monitored via serial videoendoscopy over two weeks and objectively measured. Results: a) Assessment of the bleeding scales showed that inter and intra observer reliability for both scales tested were significantly improved by employing a standardized video-endoscopy technique. The Wormald scale proved to be more reliable and sensitive to changes in the most common surgical fields encountered in ESS. b) Tranexamic acid showed a modest but clinically significant improvement in the surgical field at 2, 4 and 6 minutes after application. Epsilon aminocaproic acid did not effectively improve the surgical field. c) Nasal fibroblast adhesion and proliferation were significantly impaired with dextran and chitosan. The most effective ratio that delayed but did not prevent wound closure were 5 % chitosan: 5 % dextran gel. d) In a standardised sheep model of mucosal wound healing the chitosan gel significantly decreased lateral nasal wall and ethmoidal adhesions at all time points. The chitosan group had a significantly greater percentage of re-epithelialisation and reciliation than control and rTF. In addition the mean cilial grade in the chitosan group was significantly better than control. e) The chitosan dextran gel was significantly more haemostatic at 2,4, and 6 minutes after injury with no significant difference noted in wound healing. Conclusions: Standardised methods of videoendoscopy and grading the surgical field in ESS are valuable tools for further research. Tranexamic acid significantly improved the surgical field to a moderate degree in ESS compared to control. Chitosan gel is a promising new powerful haemostatic bio-polymer which has a mild inhibitory effect on fibroblast attachment and proliferation. This may partially explain the significant improvement in microscopic wound healing and reduction in adhesion formation seen in a sheep model of chronic sinusitis. Future work evaluating this gel in the setting of a human trial is currently underway. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1375402 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2009

Introduction: Endoscopic sinus surgery (ESS) is at present the gold standard therapeutic modality for chronic rhinosinusitis (CRS) resistant to medical therapy. Whilst results from ESS for CRS are generally good, postoperative bleeding and impaired wound healing with adhesion formation remains a concern. Due to patient discomfort and the detrimental effects on wound healing caused by most packing materials, many surgeons no longer routinely use nasal packing. Surgeons have in the past sought agents which would provide post-operative haemostasis without detrimentally affecting wound healing. Antifibrinolytics have been available for many years, however, their topical application has only been explored in the last few years. Recently different forms of chitosan have separately shown significant promise as powerful haemostatic and anti-adhesion agents. The aim of this thesis was to explore the progressive understanding of the interaction between haemostasis and wound healing with possible development of a novel agent. Methods: The first step to scientifically assess bleeding after sinus surgery was to develop a standardised method of video endoscopy and grading the surgical field during ESS. This was done as a multinational collaborative trial. Once this assessment tool was validated a randomised controlled trial evaluating the effect of two antifibrinolytics (epsilon aminocaproic acid and tranexamic acid) was conducted. Further evaluation was then conducted on other possible hemostatic and antiadhesion substances. This included various combinations of a novel chitosan gel. These gels were trialled in vitro to determine their effect on human nasal fibroblasts derived from CRS patients. Fibroblast adhesion and proliferation as well as closure of standardised wounds were studied. The most promising of these gels was then used in an in vivo sheep model. Once effectiveness of the chitosan-dextran gel was shown in the laboratory, this was evaluated against a number of currently available hemostatic and anti-adhesion substances in a standardised model of wound healing in sheep with CRS. This model had been previously extensively validated in our department. Full thickness mucosal injuries were created on the lateral nasal wall and ethmoids of twenty sheep and recombinant tissue factor (rTF), SprayGel or Chitosan-Dextran derivative gel applied topically in a randomized fashion. Adhesion formation and severity as well as microscopic wound healing and ciliary function were analysed at day 28, 56, 84 and 112 post initial surgery. A further sheep study was conducted applying chitosan dextran gel to standardised mucosal injuries and comparing its effect on the control of bleeding to control. Bleeding time and grade were recorded and wound healing monitored via serial videoendoscopy over two weeks and objectively measured. Results: a) Assessment of the bleeding scales showed that inter and intra observer reliability for both scales tested were significantly improved by employing a standardized video-endoscopy technique. The Wormald scale proved to be more reliable and sensitive to changes in the most common surgical fields encountered in ESS. b) Tranexamic acid showed a modest but clinically significant improvement in the surgical field at 2, 4 and 6 minutes after application. Epsilon aminocaproic acid did not effectively improve the surgical field. c) Nasal fibroblast adhesion and proliferation were significantly impaired with dextran and chitosan. The most effective ratio that delayed but did not prevent wound closure were 5 % chitosan: 5 % dextran gel. d) In a standardised sheep model of mucosal wound healing the chitosan gel significantly decreased lateral nasal wall and ethmoidal adhesions at all time points. The chitosan group had a significantly greater percentage of re-epithelialisation and reciliation than control and rTF. In addition the mean cilial grade in the chitosan group was significantly better than control. e) The chitosan dextran gel was significantly more haemostatic at 2,4, and 6 minutes after injury with no significant difference noted in wound healing. Conclusions: Standardised methods of videoendoscopy and grading the surgical field in ESS are valuable tools for further research. Tranexamic acid significantly improved the surgical field to a moderate degree in ESS compared to control. Chitosan gel is a promising new powerful haemostatic bio-polymer which has a mild inhibitory effect on fibroblast attachment and proliferation. This may partially explain the significant improvement in microscopic wound healing and reduction in adhesion formation seen in a sheep model of chronic sinusitis. Future work evaluating this gel in the setting of a human trial is currently underway. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1375402 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2009

The cytoskeleton is an intrinsic aspect of all cells, and is essential for many cellular events including cell motility, endocytosis, cell division and wound healing. Remodeling of the cytoskeleton in response to these cellular activities leads to significant alterations in the morphology of the cell. One such alteration is the formation of an actomyosin contractile array required for cytokinesis, wound healing and embryonic development. / Cellular structure and shape depends upon tensional prestress brought about by the organization of cytoskeletal components. Using the Xenopus laevis oocyte wound healing model, it is first described how diminished cellular tension affects the balance of the Rho family of GTPases, and subsequently prevents the formation of actomyosin contractile arrays. This suggests that cellular tension in the cell is not created at the level of the cytoskeletal elements but rather via the upstream signaling molecules: RhoA and Cdc42. / The role of N-WASP (Neural-Wiscott Aldrich Syndrome Protein), a mediator of Arp2/3 based actin polymerization, is next examined for its putative role in cellular wound healing. Xenopus laevis oocytes injected with mutant N-WASP constructs reveals in vivo evidence that functional N-WASP is required for appropriate contractile array formation and wound closure. / Lastly, it is revealed that the cellular structures involved with single cell wound healing in other model systems are also important for the initial repair of severed muscle cells. Actin, non-muscle myosin-II, microtubules, sarcomeric myosin and Cdc42 are all recruited and reorganized at the edge of damaged C2C12 myotubes. This data promotes the possibility that an actomyosin array may be established in injured muscle cells as well.