Panta Rhei: Neovascularization, Angiogenesis and Nutritive Perfusion in Wound Healing.

BACKGROUND: In response to tissue damage, angiogenesis is an extremely dynamic process that is finely regulated by signals from cells, the surrounding extracellular matrix (ECM), and derived mediators. As the only process, angiogenesis remains of decisive importance in the context of the entire wound healing process and is subject to constant change. The dissolution of the endothelial basement membrane, the migration of endothelial cells, and the development of new capillary vessels during wound healing depend not only on the cells and cytokines present, but also on the production and organization of ECM components in the immediate wound. SUMMARY: Angiogenesis in wound healing can be divided into two main phases. During the pro-angiogenic phase at the beginning of wound healing, excessive neo-formation of blood vessels, some of which are poorly differentiated, occurs, which restore blood flow and thus nutritive perfusion as quickly as possible. This is followed by an anti-angiogenic phase in which the initially established vascular network undergoes a maturing process, which, however, is accompanied by a significant reduction in the number of vessels. Key Messages: Although many mechanisms and specific cell functions in wound healing have already been described, many underlying pathophysiological processes remain unknown. Because angiogenesis and its maturation is a very fast but also very long-lasting process, the understanding of the underlying mechanisms is of crucial importance. This article will give an overview of the current understanding and controversy in this sub-step of wound healing.

Short-term effects of extracorporeal shock waves on microcirculation.

BACKGROUND: Extracorporeal shock wave application (ESWA) has the potential to qualify as an adjuvant therapy option for soft tissue disorders such as chronic wounds. As of today, little is known about its exact mechanism of action. For a better understanding of the pathophysiology, we investigated the effect of ESWA on microcirculation and leukocyte-endothelial interaction. MATERIALS AND METHODS: Intravital fluorescent microscopy was used to quantify microcirculatory parameters in the ears of hairless mice (n = 30). Values were obtained just before and 10 min after the ESWA (500 shots, 1 Hz, duration 500 s). Mice were randomly divided into three groups undergoing different shock wave intensities (energy flux density: control: 0.00 mJ/mm(2); low level: 0.015 mJ/mm(2); and higher level (hl): 0.04 mJ/mm(2); n = 10 mice per group). Histologic evaluations were taken after completion of the experiments. RESULTS: A significant increase in the venular diameter was observed in both the groups that underwent ESWA compared with the control group (hl: 118%, low level: 117%, and control: 96%; P < 0.004). Edema formation increased significantly in group I (P = 0.002). ESWA provoked an arteriolar constriction (hl: 93% versus control: 104%; P = 0.019) 10 min after treatment. The highest value of venular blood flow was found in group hl. Moreover, shock waves increased significantly the number of sticking leukocytes immediately after application (hl: 274%, P = 0.003). CONCLUSIONS: ESWA has a significant and immediate impact on microcirculation with endothelial integrity loss and increase of adherent leukocytes as part of a proinflammatory process. Although a dilation of venules was caused, arterioles primarily show a constriction. The study shows alterations in microcirculation that could help understand the mechanism of action in the future.

[Complete Occlusion of the radial Artery by a cardiogenic Embolus in infective Endocarditis]. / Komplette Okklusion der Arteria radialis durch einen kardiogenen Embolus bei infektiöser Endokarditis.

We present a case of septic embolization of the right radial artery by a cardiogenic embolus resulting from infective endocarditis. After the first suspicion of a palmar forearm phlegmon due to tenosynovitis was voiced, surgery revealed a long-segment occlusion of the radial artery. We resected the thrombosed part of the artery and reconstructed the latter with a vein interposition graft. Further diagnostic evaluation by echocardiography revealed vegetations on the anterior mitral leaflet. Reconstruction of the mitral valve was performed by annuloplasty.

Sterilization of heat-sensitive silicone implant material by low-pressure gas plasma.

BACKGROUND: In recent years, plasma treatment of medical devices and implant materials has gained more and more acceptance. Inactivation of microorganisms by exposure to ultraviolet (UV) radiation produced by plasma discharges and sterilization of medical implants and instruments is one possible application of this technique. The aim of this study was to evaluate the effectiveness of this sterilization technique on silicone implant material. METHODS: Bacillus atrophaeus spores (10(6) colony-forming units [CFUs]) were sprayed on the surfaces of 12 silicone implant material samples. Four plasma sets with different gas mixtures (argon [Ar], argon-oxygen [Ar:O(2)], argon-hydrogen [Ar:H(2)] and argon-nitrogen [Ar:N(2)]) were tested for their antimicrobial properties. Post-sterilization mechanical testing of the implant material was performed in order to evaluate possible plasma-induced structural damage. RESULTS: The inductively coupled low-pressure plasma technique can achieve fast and efficient sterilization of silicone implant material without adverse materials effects. All four gas mixtures led to a significant spore reduction, and no structural damage to the implant material could be observed.

Leiomyosarcoma of intravascular origin--a rare tumor entity: clinical pathological study of twelve cases.

BACKGROUND: Leiomysarcoma of intravascular origin is an exceedingly rare entity of malignant soft tissue tumors. They are most frequently encountered in the retroperitoneum arising from the inferior vena cava and are scarcely found to arise from vessels of the extremities. These tumors were analysed with particular reference to treatment outcome and prognosis. The aim of this article is to broaden the knowledge of the clinical course of this rare malignancy. METHOD: During 2000 and 2009 twelve patients were identified with an intravascular origin of a leiomyosarcoma. Details regarding the clinical course, follow-up and outcome were assessed with focus on patient survival, tumor relapse and metastases and treatment outcome. 3 year survival probability was calculated using Kaplan-Meier method. RESULTS: Vascular leiomyosarcomas accounted for 0.7% of all malignant soft tissue tumors treated at our soft tissue sarcoma reference center. The mean follow up period was 38 months. Tumor relapse was encountered in six patients. 6 patients developed metastatic disease. The three year survival was 57%. CONCLUSION: Vascular leiomysarcoma is a rare but aggressive tumor entity with a high rate of local recurrence and metastasis.

Proximal major limb amputations--a retrospective analysis of 45 oncological cases.

BACKGROUND: Proximal major limb amputations due to malignant tumors have become rare but are still a valuable treatment option in palliation and in some cases can even cure. The aim of this retrospective study was to analyse outcome in those patients, including the postoperative course, survival, pain, quality of life, and prosthesis usage. METHODS: Data of 45 consecutive patients was acquired from patient's charts and contact to patients, and general practitioners. Patients with interscapulothoracic amputation (n = 14), shoulder disarticulation (n = 13), hemipelvectomy (n = 3) or hip disarticulation (n = 15) were included. RESULTS: The rate of proximal major limb amputations in patients treated for sarcoma was 2.3% (37 out of 1597). Survival for all patients was 42.9% after one year and 12.7% after five years. Survival was significantly better in patients with complete tumor resections. Postoperative chemotherapy and radiation did not prolong survival. Eighteen percent of the patients with malignant disease developed local recurrence. In 44%, postoperative complications were observed. Different modalities of postoperative pain management and the site of the amputation had no significant influence on long-term pain assessment and quality of life. Eighty-seven percent suffered from phantom pain, 15.6% considered their quality of life worse than before the operation. Thirty-two percent of the patients who received a prosthesis used it regularly. CONCLUSION: Proximal major limb amputations severely interfere with patients' body function and are the last, albeit valuable, option within the treatment concept of extremity malignancies or severe infections. Besides short survival, high complication rates, and postoperative pain, patients' quality of life can be improved for the time they have remaining.

Alveolar soft part sarcoma: clinicopathological findings in a series of 11 cases.

BACKGROUND: Alveolar sarcoma of the soft parts (ASPS) represents a very rare entity of soft tissue sarcoma with special features such as young peak age incidence and frequent metastasis to the brain. The aim of this study was a clinicopathological analysis with special reference to treatment and outcome. METHODS: From the database of the BG-University Hospital Bergmannsheil, 1597 soft tissue sarcoma (STS) cases were reviewed and 11 consecutive patients with ASPS were isolated. Data was acquired from patients' charts and contact to patients, their relatives or general practitioners, with special reference to treatment and clinical course. The average follow up time from the time of the definite operation for the primary tumor was 6.5 years. Kaplan-Meier method was used to calculate survival. RESULTS: Patients with localized disease who received complete resection and adjuvant radiation and who did not develop recurrence or metastatic disease within 2 years after surgery had a positive outcome. The size of the tumor, its localization, and the time of untreated growth before treatment did not influence the long-term results. All patients who developed recurrent disease also suffered from distant metastasis, reflecting the aggressive biology of the tumor. All patients with distant metastasis had the lungs and the brain affected. CONCLUSION: Due to the limited number of patients with ASPS, prospective studies would have to span decades to gather a significant collective of patients; therefore, it is not possible to comment meaningfully on a possible benefit of neoadjuvant or adjuvant therapy. We recommend wide surgical excision and, in the absence of data telling otherwise, adjuvant radiation. In cases with recurrent disease or metastasis, the prognosis is bad and further treatment will be restricted to palliation in most cases.

Trocar injury of the retroperitoneal vessels followed by life-threatening postischemic compartment syndrome of both lower extremities.

BACKGROUND: Lesions of the intra-abdominal organs and vessels caused by trocars and Verres needles are rare but serious complications during laparoscopic surgery. REPORT: We report an unusual case of left common iliac artery and inferior vena cava injury during laparoscopy. This lesion was followed by a bilateral postischemic compartment syndrome of the lower extremities. The patient sustained massive rhabdomyolysis, renal failure, peroneal nerve palsy, and functional loss of the lower extremities. CONCLUSION: Postischemic tissue swelling should be recognized as early as possible because it is a life-threatening condition that necessitates immediate treatment.

A Novel Technique for the Standardized Application of Shock Waves in Experimental Research: The Diver Box.

The Diver Box is designed to prevent impedance differences, energy loss or damage to neighboring structures caused by the use of shock waves with application gels. The Diver Box is an acrylic glass container filled with tempered water and includes a coupling membrane to prevent the impedance jump from air to water and to avoid the continuous propagation of shock waves into the tissue, maintaining wave dynamics. Different modes of extracorporeal shock waves can be applied to a mouse skin wound without energy loss and protected from harmful phase-reversed waves. Macroscopic changes were seen in only 5% to 12% of tested specimens. Hazardous phase reversal, back reflection and mechanical tissue damage can be avoided by use of the Diver Box, ensuring standardized extracorporeal shock wave application.

Efficacy of Conventional and Liposomal Povidone-Iodine in Infected Mesh Skin Grafts: An Exploratory Study.

INTRODUCTION: Infection is a major threat to wound healing and a leading cause of graft loss in patients undergoing meshed skin grafts (MSGs). Therefore, topical antisepsis is important in the overall treatment scheme. METHODS: An exploratory satellite group of 14 patients with infected MSGs were enrolled as part of a prospective, randomized, controlled, parallel-group, open-label, pilot Phase II study that investigated the efficacy and tolerability of 3% liposomal povidone-iodine hydrogel (PVP-ILH, Repithel®; RepiGel®) versus chlorhexidine gauze in non-infected MSGs. The satellite group included both patients with infected wound beds prior to grafting and patients with infection of a previously placed graft, with MSG sizes ranging from 50 to 1000 cm2, who were randomized to treatment with (PVP-ILH) or 10% povidone-iodine ointment (Betaisodona®; BETADINE®). Medication was applied in a 2-mm layer and dressing changes with identical application of study medication took place daily. Wounds were evaluated by photoplanimetry, microbiologically and subjectively by patients and physicians. RESULTS: The results for the main study group have been reported previously. In the satellite group, both PVP-ILH and povidone-iodine ointment performed remarkably well with respect to lowering the bacterial count and restoring wound healing, with different emphasis. Povidone-iodine ointment showed excellent antibacterial efficacy with no detectable microorganisms by Day 10, and rapid re-epithelialization (mean 90% by Day 6). PVP-ILH also demonstrated rapid re-epithelialization (mean 72% by Day 6) with a trend towards improved subjective measures of wound healing quality. Four patients (40%) receiving PVP-ILH experienced partial graft loss (10-15% of total MSG area); no patients in the povidone-iodine ointment group experienced graft loss. CONCLUSION: Our results suggest that povidone-iodine ointment has a strong role in managing infected wounds, especially when a high concentration of povidone-iodine may be warranted, while PVP-ILH indicated similar beneficial results on markers of wound healing quality in larger infected wounds. TRIAL REGISTRATION: The trial was conducted prior to mandatory registration of drug products, PVP-ILH represents a medicated device in the EU and many other countries. FUNDING: Mundipharma Research GmbH & Co. KG.

Severe burn injuries induced by PUVA chemotherapy.

Psoralen-ultraviolet A (PUVA) chemotherapy is an established treatment for certain skin diseases. Burn injury is a serious complication of PUVA therapy. Reports regarding this complication are limited. The aim of this study was to determine the management and outcome of severe PUVA burns. A retrospective review of the medical records of PUVA burns treated at our burn center from 2000 to 2010 was conducted. Data collected included age, sex, condition, mode of PUVA, site, surface area involved, depth of burns, onset of reactions, treatment, and inpatient stay. To evaluate the incidence of this severe complication, a survey of all listed burn care units in Germany, Austria, and Switzerland as well as the legal advisory boards of the medical associations of the federal states of Germany was conducted. The conditions leading to photochemotherapy were three cases of psoriasis vulgaris and one case of severe chronic graft vs host disease. All patients received oral psoralen. Incorrect handling of the radiation system was the reason for all burns. The mean affected TBSA was 73±18%. All patients were treated conservatively and healed without surgical intervention. Burn injury is a serious and preventable complication of PUVA photochemotherapy. Patients should be advised regarding the potential risk of major burns. Care should be given to not exceed the safe dose of psoralen. Burn care specialists must restrain surgical intervention as even deep partial thickness PUVA burns have the potential to heal spontaneously.

The Vascularised Groin Chamber: A Novel Model for Growing Primary Human Liposarcoma in Nude Mice.

BACKGROUND: The preclinical development of anti-sarcoma drugs has been primarily based on the subcutaneous transplantation of xenografts. Transplant survival remains an obstacle of current models which has been attributed to the period of hypoxia after transplantation. We hypothesized that primary soft tissue sarcoma models with an intrinsic tissue engineered vascular supply would be easily reproducible. The aim of this study was to establish a model of primary human soft tissue sarcoma with an intrinsic vascular supply. METHODS: Primary soft tissue sarcoma cells from resected human liposarcomas isolated and divided into tumour fragments were transplanted into a silicon chamber, placed around the superficial epigastric vessels in mice. Sarcoma xenograft samples were analysed histomorphologically (light/electron microscopy and immunohistochemistry). RESULTS: All primary soft tissue sarcoma transplants engrafted, leading to solid tumours within 3 weeks. Histological and immunohistochemical staining confirmed the mouse xenografts as identical high grade liposarcomas compared to original tumour tissue. CONCLUSION: This study established a reproducible xenograft model of primary human liposarcoma. This animal model could be of high value for studying human soft tissue sarcomas and their therapy.

A novel xenograft model with intrinsic vascularisation for growing undifferentiated pleomorphic sarcoma NOS in mice.

PURPOSE: Preclinical development of antisarcoma therapy is primarily based on the subcutaneous transplantation of sarcoma xenografts. Tumour cell survival remains a hurdle of current models, which has been attributed to the hypoxic conditions following transplantation. We hypothesised that sarcoma models with an intrinsic tissue-engineered vascular supply are easily reproducible. The aim of this study was to establish a novel vascularised xenograft model. MATERIALS AND METHODS: Primary human soft tissue sarcomas were transplanted into a silicon chamber and placed around the superficial epigastric vessels of nude mice. Sarcoma xenograft samples were assessed histomorphologically. RESULTS: All sarcoma xenografts engrafted, leading to solid tumours. Histological, immunohistochemical staining and light/electron microscopy confirmed the xenografts as identical high-grade pleomorphic sarcomas (NOS) compared with the original patients' tumours. CONCLUSION: This novel sarcoma xenograft model with an intrinsic vascular supply could be of high value for studying human soft tissue sarcomas and their therapy.

Sarcoma cells induce alteration in adipogenic differentiation.

BACKGROUND: Sarcomas consist of both tumor and stromal cells, and the interaction between these compartments is critical for tumor progression and metastasis. Tumor-derived factors may alter the differentiation capacity of the adjacent stromal cells. The aim of this study was to elucidate the paracrine impact of liposarcoma cells on pre-adipocytes, their adipogenic differentiation process and miRNA expression profile. MATERIALS AND METHODS: 3T3-L1 pre-adipocytes were exposed to sarcoma pre-conditioned media. Following induction of adipogenic differentiation morphometrical changes were assessed. Differences in miRNA expression of conditioned and non-conditioned 3T3-L1 cells were analyzed. RESULTS: Exposure to sarcoma pre-conditioned media substantially altered the differentiation capability of 3T3-L1 pre-adipocytes. Significant changes in the miRNA expression profile between conditioned and non-conditioned pre-adipocytes were observed. CONCLUSION: Sarcoma cells directly modulate pre-adipocyte differentiation. This study demonstrates that sarcoma cells influence differentiation of pre-adipocytes via paracrine factors and alter their miRNA expression.

Experimental murine model of primary high grade undifferentiated pleomorphic sarcoma not otherwise specified.

BACKGROUND: Undifferentiated pleomorphic sarcoma not otherwise specified (NOS) is a malignant neoplasm of uncertain origin arising both in the soft tissue and the bone. The WHO classified this tumour in 2002 but controversy has plagued this entity due to limited availability of tissue for study. The aim of this study was to establish a reproducible xenograft model of primary human undifferentiated pleomorphic sarcoma NOS. MATERIALS AND METHODS: Primary human sarcoma samples were divided into tumour fragments and transplanted subcutaneously in mice. Sarcoma xenografts were analysed histolomorphologically (light/electron-microscopy; immunohistochemistry). RESULTS: All tumours resulted in viable sarcoma NOS xenografts demonstrating similar histological patterns. In both the original tumours and the xenografts, tumour necrosis was found ranging from 15% to 25%. The background stroma of the xenografts was hyalinised like the primary sarcoma. Electron microscopical analyses showed good maintenance of ultrastructure. CONCLUSION: Implantation of intact tumor fragments yielded in a complete tumor take rate. The development of new cancer therapeutics requires animal models that closely resemble the human patient. This study provides ideal animal models for the research of pathogenesis and pathobiology of primary human undifferentiated pleomorphic sarcoma NOS.

Establishing efficient xenograft models with intrinsic vascularisation for growing primary human low-grade sarcomas.

BACKGROUND: There are no xenograft models of low-grade soft tissue sarcoma. Transplant survival remains an obstacle in sarcoma xenograft models and is attributed to post-transplantation hypoxia. Models with an intrinsic tissue - engineered vascular supply may overcome this obstacle. The aim of this study was to establish a novel xenograft model of primary human low grade soft tissue sarcoma. MATERIALS AND METHODS: Primary low-grade liposarcoma fragments were transplanted into a silicon chamber, placed around the superficial epigastric vessels in athymic nude mice. Xenograft samples were assessed histologically (light/electron microscopy and immunohistochemistry for S100). RESULTS: All xenotransplants of low grade primary soft tissue liposarcoma (n=4) engrafted, led to the development of solid tumours in mice. Histological and immunohistochemical staining confirmed the xenografts as being well-differentiated liposarcomas identical to the original tumor tissue. CONCLUSION: Successful transplantation of human low-grade liposarcoma tissue in mice was established for the first time using a model with an intrinsic vascular supply.

Induction of angiogenesis and neovascularization in adjacent tissue of plasma-collagen-coated silicone implants.

OBJECTIVE: Formation of encapsulating, avascular fibrous tissue is deemed to decrease implant's biocompatibility and versatility. We investigated whether plasma-mediated collagen coating possesses the ability to enhance neovascularization in the vicinity of silicone implants. METHODS: Plasma-treated collagen-I-coated silicone samples were placed into the dorsal skinfold chambers of female balb/c mice (n = 10). Conventional silicone served as control (n = 10). Intravital microscopy was performed within implant's surrounding tissue on days 1, 5, and 10. Functional vessel density, intervascular distance, vessel diameter, microvascular permeability, red blood cell velocity, and leukocyte-endothelium interaction were determined. RESULTS: Enhanced angiogenesis in the tissue surrounding plasma-pretreated collagen-coated implants was noted. Significant increase of functional vessel density due to vascular new development was observed (t test, P < .05). Analyses of microvascular permeability and red blood cell velocity displayed stable perfusion of the vascular network neighboring the surface-modified implants. CONCLUSION: Intensified vascularity due to induced angiogenesis and neovascularization in the tissue surrounding plasma-collagen-coated samples were observed. These results indicate that plasma-mediated collagen coating might be a promising technology in order to improve the biocompatibility and versatility of silicone implants.

Plasma mediated collagen-I-coating of metal implant materials to improve biocompatibility.

This study describes the collagen-I coating of titanium and steel implants via cold low-pressure gas plasma treatment. To analyze the coatings in terms of biocompatibility osteoblast-like osteosarcoma cells and human leukocytes were cultivated on the metal surfaces. Two different implant materials were assessed (Ti6Al4V, X2CrNiMo18) and four different surface properties were evaluated: (a) plasma pretreated and collagen-I coated implant materials; (b) collagen-I dip-coated without plasma pretreatment; (c) plasma treated but not collagen-I coated; (d) standard implant materials served as control. The different coating characteristics were analyzed by scanning electron microscopy (SEM). For adhesion and viability tests calcein-AM staining of the cells and Alamar blue assays were performed. The quantitative analysis was conducted by computer assisted microfluorophotography and spectrometer measurements. SEM analysis revealed that stable collagen-I coatings could not be achieved on the dip-coated steel and titanium alloys. Only due to pretreatment with low-pressure gas plasma a robust deposition of collagen I on the surface could be achieved. The cell viability and cell attachment rate on the plasma pretreated, collagen coated surfaces was significantly (p < 0.017) increased compared to the non coated surfaces. Gas plasma treatment is a feasible method for the deposition of proteins on metal implant materials resulting in an improved biocompatibility in vitro. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.

Synergistic effects of sonoporation and taurolidin/TRAIL on apoptosis in human fibrosarcoma.

Sonodynamic therapy, in combination with ultrasound contrast agents, proved to enhance the uptake of chemotherapeutics in malignant cells. HT1080 fibrosarcoma cells were treated in vitro with a combination of ultrasound SonoVue™-microbubbles and taurolidine (TRD) plus tumor necrosis factor related apoptosis inducing ligand (TRAIL). Apoptosis was measured by TdT-mediated dUTP-biotin nick end labelling (TUNEL) assay and fluorescence activated cell sorting (FACS) analysis. Gene expression was analysed by RNA-microarray. The apoptotic effects of TRD and TRAIL on human fibrosarcoma are enhanced by sonodynamic therapy and additional application of contrast agents, such as SonoVue™ by 25%. A broad change in the expression of genes related to apoptotic pathways is observed when ultrasound and microbubbles act synchronously in combination with the chemotherapeutics (e.g. BIRC3, NFKBIA and TNFAIP3). Some of these genes have already been proven to play a role in programmed cell death in human fibrosarcoma (HSPA1A/HSPA1B, APAF1, PAWR, SOCS2) or were associated with sonication induced apoptosis (CD44). Further studies are needed to explore the options of sonodynamic therapy on soft tissue sarcoma and its molecular mechanisms.

Ultrasound-induced modifications of cytoskeletal components in osteoblast-like SAOS-2 cells.

In clinical and experimental studies an acceleration of fracture healing and increased callus formation induced by low-intensity pulsed ultrasound (LIPUS) has been demonstrated. The exact molecular mechanisms of ultrasound treatment are still unclear. In this study ultrasound transmitted cytoskeletal and growth rate changes of SAOS-2 cells were examined. Osteoblast-like cell lines (SAOS-2) were treated using low-intensity pulsed ultrasound. Cytoskeletal changes were analyzed using rhodamine phalloidine for f-actin staining and indirect immunofluorescence techniques with different monoclonal antibodies against several tubulin modifications. To examine changes of cell number after ultrasound treatment cell counts were done. Significant changes in cytoskeleton structure were detected compared to controls, including an enhancement of stress fiber formation combined with a loss of cell migration after ultrasound application. We further observed that sonication altered the proportion of the more stable microtubules to the more labile microtubule subclass. The labile tyrosinated microtubules appeared highly enhanced, whereas the amount of the more stable acetylated microtubules was remarkably diminished. All these observations were quantified by fluorometric measurements. The centrosomal gamma-tubulin was frequently scattered throughout the cell's cytoplasm, giving rise to additional polyglu-positive microtubular asters, which induced multipolar spindles, leading either to aneuploid mini-or giant cells. Moreover, a significant increase of cell number was noticed in the sonicated group. These experiments demonstrate that ultrasound treatment increases cell number and leads to significant changes of the cytoskeletal structure and composition in vitro.