Donor-derived transplant acceptance-inducing cells in composite tissue allotransplantation.

BACKGROUND: Composite tissue allotransplantation (CTA) is a newly emerging field of transplantation. Immunological research in CTA has been intensified due to the recent clinical success of hand and face transplantation. Establishing immunological tolerance by adoptive transfer of ex vivo cultured tolerance-inducing cell types is of growing interest. Transplant acceptance-inducing cells (TAICs) are a type of deactivated immunoregulatory macrophages. METHODS: A total of 36 allogeneic hind limb transplantations in the rat were performed in six groups. Group A (Lewis (LW) â†’ Brown-Norway (BN)) received Lewis-donor-derived TAICs locally (i.m.). Group B (LW â†’ BN) received Lewis-donor-derived TAICs systemically (i.v.) and group C (Sprague Dawley (Sp-D) â†’ BN) served as a control group receiving Lewis-donor-derived TAICs systemically (i.v.). Groups D (LW â†’ BN), E (LW â†’ BN), and F (BN â†’ BN) also served as control groups with group D receiving no immunosuppression, group E receiving FK506 and prednisolone and group F receiving no immunosuppression with isograft transplantations (BN â†’ BN). The timing of rejection was assessed by clinical observation and histological findings. RESULTS: Rejection of the allogeneic hind limb occurred on average 7.7 days after transplantation in group A and 7.4 days in group B. Rejection was significantly delayed (Log-rank test, p < 0.01) compared to groups C and D, where rejection of the allogeneic hind limb occurred on average 5.8 days and 5.6 days after transplantation. No rejection was seen in groups E and F. CONCLUSION: For the first time, TAICs have been applied in a CTA model and demonstrated a significant immunosuppressive effect. Even though the immunomodulatory effect is relatively modest, the results of this study justify subsequent research on TAIC therapy to improve experimental and clinical outcome after CTA.

[Pyoderma gangraenosum as a major complication in breast reconstruction with free double-DIEP-flap]. / Pyoderma gangraenosum als Major-Komplikation bei einer Brustrekonstruktion mit freier Doppel-DIEP-Lappenplastik.

BACKGROUND: Pyoderma gangraenosum (PG) as an idiopathic, ulcerative inflammatory skin disease with varying clinical pictures has an estimated incidence of 0.3/100,000 and is due to the non-specific histology primarily a clinical exclusion diagnosis. The rapid progression, as well as the often fatal course of the pathergy phenomenon after surgical intervention is a therapeutic challenge. With the example of the complicated course of a 47-year-old patient with free DIEP flap for bilateral breast reconstruction due to PG, we want to direct attention to this often underrated disease. PATIENTS: For bilateral breast reconstruction, a 47-year-old patient received a double free DIEP flap, which had to be resected on the right due to multiple arterial thromboses. The clinical presumptive diagnosis of a PG arose and an IV steroid therapy was started immediately. After 13 days a further debridement and mesh graft transplantation were performed. Now, the histological examination was for the first time compatible with PG. Under the initiated steroid treatment the wounds could be stabilised and the remaining defects could be covered. After 6-week stay, the patient was finally discharged with healed wound conditions, but an unsatisfactory aesthetic result. CONCLUSIONS: If unclear, rapidly progressive ulcers occur in surgical interventions one should always think of pyoderma gangraenosum. In particular, since a surgical intervention can result in an uncontrolled exacerbation due to the pathergy phenomenon. Laboratory parameters and histology are not specific. Under a systemic immunomodulatory therapy, a sequential surgical wound management may accelerate wound healing.

Optimizing Suprathel®-therapy by the use of Octenidine-Gel®.

OBJECTIVE: A prospective, randomized, non-blinded, clinical study was conducted to evaluate the feasibility and practicability as well as pain reduction and ease of handling of Flammazine® versus Octenidine-Gel® s a primary local antiseptic before synthetic skin substitute application in partial-thickness burns. METHODS: Thirty patients with a median age of 42 years suffering from second-degree burns were included in the study. Burns were randomly selected, one area was treated with Flammazine®/gauze, another area in the same patient was treated with Octenidine-Gel®/gauze as initial antiseptic treatment. Within 24 h the first gauze change was performed followed by wound inspection, disinfection and synthetic skin substitute application. The study focused on patient pain score, analysis of wound bed and ease of handling of the two local antiseptic agents. RESULTS: There was a significant difference between Flammazine® versus Octenidine-Gel® regarding patient pain score and ease of handling. Octenidine-Gel® was less painful (p < 0.05) and easier to handle (p < 0.05). There was no significant difference for wound bed evaluation between the two antiseptic agents. A tendency for better wound bed preparation was seen with the use of Octenidine-Gel®. CONCLUSION: Based on the findings of this study Octenidine-Gel® is recommended as a local antiseptic agent, because when compared to Flammazine®, Octenidine-Gel® proved to be better in terms of ease of care, simplicity application, with gentler and faster detachment of the gel from wound surfaces and consequently far less pain during dressing changes.

Dermal substitution with Matriderm(®) in burns on the dorsum of the hand.

BACKGROUND: Dermal substitutes are used increasingly in deep partial and full-thickness burn wounds in order to enhance elasticity and pliability. In particular, the dorsum of the hand is an area requiring extraordinary mobility for full range of motion. The aim of this comparative study was to evaluate intra-individual outcomes among patients with full-thickness burns of the dorsum of both hands. One hand was treated with split-thickness skin grafts (STSG) alone, and the other with the dermal substitute Matriderm(®) and split-thickness skin grafts. MATERIAL AND METHODS: In this study 36 burn wounds of the complete dorsum of both hands in 18 patients with severe burns (age 45.1±17.4 years, 43.8±11.8% TBSA) were treated with the simultaneous application of Matriderm(®), a bovine based collagen I, III, V and elastin-hydrolysate based dermal substitute, and split-thickness skin grafting (STSG) in the form of sheets on one hand, and STSG in the form of sheets alone on the other hand. The study was designed as a prospective comparative study. Using both objective and subjective assessments, data were collected at one week and 6 months after surgery. The following parameters were included: After one week all wounds were assessed for autograft survival. Skin quality was measured 6 months postoperatively using the Vancouver Burn Skin Score (VBSS). Range of motion was measured by Finger-Tip-Palmar-Crease-Distance (FPD) and Finger-Nail-Table-Distance (FNTD). RESULTS: Autograft survival was not altered by simultaneous application of the dermal matrix (p>0.05). The VBSS demonstrated a significant increase in skin quality in the group with dermal substitutes (p=0.02) compared to the control group with non-substituted wounds. Range of motion was significantly improved in the group treated with the dermal substitute (p=0.04). CONCLUSION: From our results it can be concluded that simultaneous use of Matriderm(®) and STSG is safe and feasible, leading to significantly better results in respect to skin quality of the dorsum of the hand and range of motion of the fingers. Skin elasticity was significantly improved by the collagen/elastin dermal substitute in combination with sheet-autografts.

Matriderm® in depth-adjusted reconstruction of necrotising fasciitis defects.

Necrotising fasciitis (NF) and Fournier's gangrene are still a source of high morbidity and mortality and a significant health-care resource consumption. These difficult cases are increasingly being referred to burn centres for specialised wound and critical care issues. Besides the total body surface area (TBSA) affected, location, co-morbidities, age and an immediate surgical treatment are important prognostic factors. The treatment of these patients is challenging and best performed by prompt diagnosis, immediate radical surgical debridement and aggressive critical care management. Referral to a major burn centre may help provide optimal surgical intervention, wound care and critical care management.As soon as the patient is stabilised, reconstruction of the injured areas becomes the main focus. As often seen, complete loss of dermal structures needs a depth adjusted--'multilayer'--reconstruction especially in critical areas. In modern reconstructive surgery, concepts of layer-specific reconstruction, including dermal substitution have to be considered. In this article, we present our recent experiences of five patients with NF who underwent dermal reconstruction with Matriderm® not only for better skin quality but also in some cases as an alternative to flap surgery when joint capsules or tendons were exposed.

Craniomedial pedicled mammaplasty based on Würinger's horizontal septum.

BACKGROUND: During 30 months, 40 "septum-based" mammaplasties with a craniomedial pedicle were performed. This report aims to demonstrate the anatomic basics of the horizontal septum and the authors' experience with the septum-based mammaplasty technique. METHODS: A series of 40 consecutive patients underwent a "septum-based" mammaplasty. This technique uses a medial pedicle based on Würinger;s horizontal septum, which is the main plain for the neural and vascular supply of the nipple-areolar complex (NAC). RESULTS: The mean nipple-to-sternal-notch distance was 32 cm (range, 24-43 cm). The mean resection weight was 648 g (range, 484-1,320 g), and the mean nipple elevation was 9.5 cm (range, 5-18 cm). There were no hematomas and no partial or complete NAC necroses. Minimal wound dehiscence at the T-junction was present in three cases (7.5%). The pre- and postoperative NAC sensibilities were comparable in all the patients. CONCLUSION: Based on Würinger;s horizontal septum, a safe and well-vascularized mammaplasty is possible even with large resection weights and long nipple-areola distances, and NAC sensibility can be preserved. The reported technique combining excellent pedicle perfusion with a wide variety of breast shaping proved to be safe.

The antimicrobial effect of acetic acid--an alternative to common local antiseptics?

Acetic acid has been commonly used in medicine for more than 6000 years for the disinfection of wounds and especially as an antiseptic agent in the treatment and prophylaxis of the plague. The main goal of this study was to prove the suitability of acetic acid, in low concentration of 3%, as a local antiseptic agent, especially for use in salvage procedures in problematic infections caused by organisms such as Proteus vulgaris, Acinetobacter baumannii or Pseudomonas aeruginosa. This study was designed to compare the in vitro antimicrobial effect of acetic acid with those of common local antiseptics such as povidone-iodine 11% (Betaisodona), polyhexanide 0.04% (Lavasept), mafenide 5% and chlohexidine gluconate 1.5% cetrimide 15% (Hibicet). Former studies suggest the bactericidal effect of acetic acid, but these data are very heterogeneous; therefore, a standardised in vitro study was conducted. To cover the typical bacterial spectrum of a burn unit, the following Gram-negative and Gram-positive bacterial strains were tested: Escherichia coli, P. vulgaris, P. aeruginosa, A. baumannii, Enterococcus faecalis, Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus (MRSA) and beta-haemolytic Streptococcus group A and B. The tests showed excellent bactericidal effect of acetic acid, particularly with problematic Gram-negative bacteria such as P. vulgaris, P. aeruginosa and A. baumannii. The microbiological spectrum of acetic acid is wide, even when tested at a low concentration of 3%. In comparison to our currently used antiseptic solutions, it showed similar - in some bacteria, even better - bactericidal properties. An evaluation of the clinical value of topical application of acetic acid is currently underway. It can be concluded that acetic acid in a concentration of 3% has excellent bactericidal effect and, therefore, seems to be suitable as a local antiseptic agent, but further clinical studies are necessary.

Abrogation of TGF-beta by antisense oligonucleotides modulates expression of VEGF and increases angiogenic potential in isolated fibroblasts from radiated skin.

The transforming growth factor-beta (TGF-beta) has been identified as an important component of wound healing. Recent developments in molecular therapy offer good prospects for the modulation of wound healing, specifically those targeting TGF-beta. The aim of this study was to analyze the effect of TGF-beta targeting on the expression of angiogenic vascular endothelial growth factor (VEGF), a key regulator of angiogenesis and in vitro angiogenic activity in fibroblasts isolated from radiation-induced chronic dermal wounds. The expression of angiogenic VEGF in tissue samples from radiation-induced chronic dermal wounds was investigated by immunohistochemistry and microarray technique. The effect of TGF-beta targeting using antisense oligonucleotides on the expression of VEGF in isolated fibroblasts was analyzed by ELISA and multiplex RT-PCR. Human endothelial cells (ECs) were grown in conditioned medium produced from the treated fibroblasts. EC migration was measured using a modified Boyden chamber; EC tube formation was analyzed under a light microscope. Immunohistochemical investigation and microarray analysis demonstrated a decreased expression of VEGF protein and mRNA in tissue samples from radiation-induced chronic dermal wounds compared to normal human skin. Antisense TGF-beta oligonucleotide treatment significantly up-regulated VEGF secretion in vitro. Addition of conditioned medium from TGF-beta antisense-treated fibroblasts resulted in an increase in EC cell migration and tube formation. In conclusion, our results demonstrate that TGF-beta antisense oligonucleotide technology may be a potential therapeutic option for stimulation of angiogenesis in radiation-induced dermal wounds.

[Pathogenesis of chronic wounds]. / Pathophysiologie der chronischen Wunde.

Chronic, nonhealing wounds and their therapy are not only a medical problem but a severe economic one as well. Such wounds have a great effect on quality of life. Basic research has enhanced our understanding of the stimulation and inhibition of wound healing and provides the basis for introducing new and innovative treatment methods. This paper reviews the most relevant in- and extrinsic factors that disturb physiologic wound healing to result in chronic nonhealing wounds. In addition, molecular intervention modalities targeting various aspects of wound repair are demonstrated.

TGF-beta antisense oligonucleotides modulate expression of matrix metalloproteinases in isolated fibroblasts from radiated skin.

BACKGROUND: Transforming growth factor-beta (TGF-beta) has been identified as an important component of wound healing. Recent developments in molecular therapy offer exciting prospects for the modulation of wound healing, specifically those targeting TGF-beta. The purpose of this study was to analyze the effect of TGF-beta targeting on the expression of matrix metalloproteinases (MMPs) in fibroblasts isolated from radiation-induced chronic dermal wounds. MATERIALS AND METHODS: The expression of MMPs in tissue samples from radiation-induced chronic dermal wounds was investigated by immunohistochemistry and microarray technique. The effect of TGF-beta targeting using antisense oligonucleotides on the expression of MMPs in isolated fibroblasts was analysed by ELISA and multiplex RT-PCR. RESULTS: Immunohistochemical investigation and microarray analysis demonstrated an increased expression of MMP protein and mRNA in tissue samples from radiation-induced chronic dermal wounds compared to normal human skin. Antisense TGF-beta oligonucleotide treatment significantly down-regulated MMP secretion in vitro. CONCLUSION: TGF-beta antisense oligonucleotide technology may be a potential therapeutic option for the inhibition of proteolytic tissue destruction in radiation-induced chronic wounds.

[Plastic surgery for the treatment of gynaecomastia following hormone therapy in prostate carcinoma]. / Die plastische chirurgische Therapie der Gynäkomastie nach antihormoneller Therapie bei Prostatakarzinom.

Gynecomastia is a potential side effect of hormone therapy for prostate cancer. In large, randomized, placebo controlled studies approximately 50% or more of patients with prostate cancer experienced gynecomastia attributable to various mechanisms. Although it is mostly reported as mild to moderate, gynecomastia is one of the reasons most frequently cited for premature discontinuation of such treatment. Prophylactic radiotherapy and prophylactic tamoxifen have been shown to decrease the incidence of hormone-induced gynecomastia; nevertheless, there are still cases of refractory gynecomastia, and in these plastic surgery is needed for correction. Gynecomastia is a benign enlargement of the male breast, requiring no treatment unless it is a source of embarrassment and/or distress for the adolescent or man affected. The indications for surgical treatment of gynecomastia are founded on two main objectives: restoration of the male chest shape and diagnostic evaluation of suspected breast lesions. The authors believe that the complete circumareolar technique with no further scarring creates the best aesthetic results with fewer complications. When this is used in combination with liposuction very pleasing aesthetic results can be achieved.

The use of MatriDerm in early excision and simultaneous autologous skin grafting in burns--a pilot study.

The application of dermal substitutes in deep partial and full-thickness burn wounds in a two-stage procedure prior to skin grafting has become increasingly popular. Synchronous application of dermal substitutes and skin graft has not yet been established as a standard procedure. In a consecutive study 20 wounds in 10 patients with severe burns (age 49.5+/-16.2 years; TBSA 45.6+/-14.5%) were treated with either simultaneous transplantation of Matriderm, a bovine based collagen I, III, V and elastin hydrolysate based dermal substitute and split-thickness skin grafting (STSG), or STSG alone after appropriate excision of the burn wound. The study was designed as a prospective intra-individual comparative study. After 1 week all wounds were assessed for the percentage of autograft survival. Autograft survival was not altered by simultaneous application of a dermal matrix (p=0.015). Skin elasticity was measured after 3-4 months with the Vancouver Burn Skin Score (VBSS). The VBSS demonstrated a significant increase of elasticity in the group with dermal substitutes (p=0.04) as compared with non-substituted wounds for sheet autograft, but not for meshed autograft (p=0.24). From this pilot study it can be concluded that simultaneous application of a dermal matrix is safe and feasible, yielding significantly better results with respect to skin elasticity. Skin elasticity was considerably improved by the collagen/elastin dermal substitute Matriderm in combination with sheet autograft.

[Surgical concept and results of necrotizing fasciitis]. / Chirurgisches Konzept und Ergebnisse bei nekrotisierender Fasziitis.

BACKGROUND: Necrotizing fasciitis (NF) is still a source of high morbidity and mortality. These difficult cases are increasingly referred to burn centers due to special wound and critical care issues. Here we examine our institution's recent experience with a large series of NF. METHOD: We performed a retrospective chart review of 32 consecutive patients over a 10-year period with NF who required radical surgical debridement and surface reconstruction. RESULTS: Overall survival was 85%, with average length of stay of 74.0+/-7.5 days for survivors (S) and 68.8+/-6.3 days for nonsurvivors (NS) (P>0.05). Time until first operation was 5.2 days in S and 3.4 days in NS (P<0.05). Patient age averaged 51.1+/-11.2 years for S and 57.0+/-12.0 years for NS (P<0.05). Survivors averaged 1.6 relevant comorbidities and NS averaged 3.6 (P<0.05). Affected total body surface (TBS) per patient averaged 6.8+/-3.3% for S and 10.2+/-5.1% for NS (P<0.05). All NS had affection of the trunk, and none of the patients with exclusive affection of extremities died. CONCLUSIONS: There were frequent delays in diagnosis and referrals to our institution, and progress can be made in educating the medical community to identify these patients. Not only the affected TBS and location but also comorbidities, age, and immediate surgical treatment are important prognostic factors. Referral to a specialized facility such as a burn center is urgently recommended for optimal surgical intervention, wound care, and critical care management.

[Plastic surgical body form correction. Part II: Face-lift, periorbital surgery, and breast augmentation and reduction]. / Plastisch-chirurgische Korrekturen der Körperform--Rekonstruktion und Asthetik. Teil II: Facelift, periorbitale Chirurgie, Mammaaugmentation und Mammareduktion.

The demand for a younger appearance is increasing as the average age of the population increases. Extensive anatomic studies in recent years have improved for facial and breast reconstruction the understanding of anatomic structures and the basis of the aging process. Numerous new surgical techniques have resulted. This understanding of the anatomy of aging and the diversity of surgical methods have made the attainment of naturally young facial appearance more easily possible, in which repositioning of the tissue plays a more important role than lifting. In the past, plastic surgery of the eyelids aimed primarily at hiding the aging process, not at true anatomic restoration. Modern techniques in this field aim more toward redistribution of fatty tissues and the anatomic restoration of aging structures. In this way long-term results are stabilized and secondary stigmata can be avoided. New concepts have also been established in breast surgery that allow more natural results, particularly in augmentation. Although no single method may be designated as superior, there still exists an optimal technique suited to every patient's anatomy and personal wishes.

[Electronic documentation of injuries of the hand with a semantic network: effective and efficient methods for the documentation of clinical and administrative processes]. / Elektronische Dokumentation handchirurgischer Verletzungen durch semantische Netze: Effektive und effiziente Methoden zur Datenerhebung klinischer und administrativer Prozesse.

BACKGROUND: An efficient medical documentation is mandatory for a trauma-oriented department in the DRG environment. Besides the continuously increasing clinical/administrative demands, the additional documentation for quality assurance, clinical studies, and research requires additional efforts. Standard solutions are only partially effective. Especially in hand surgery there is a high demand for sophisticated clinical documentation, represented by a wide variety of classifications in diagnosis and therapy. The standard documentation tools lack accuracy. The development of a software tool that defines administrative/business processes and simultaneously generates clinical and administrative information was the goal of this project. METHODS AND RESULTS: With a standard medical terminology, an innovative semantic network, and a completely new graphical user interface, it was possible to develop and introduce a software program specifically adjusted for hand surgery. This program facilitated for the first time a single-stage acquisition of clinically relevant scientific data and the simultaneous generation of DRG, quality assurance, and administrative data relevant for the hospital's revenues. CONCLUSIONS: The newly developed software tool is a step forward into a new dimension of medical software, obviating the need for multi/documentation and significantly improving the quality of clinically relevant medical data.

Comparison of CT with diffusion-weighted MRI in patients with hyperacute stroke.

Tissue changes in ischaemic stroke are detectable by diffusion-weighted MRI (DWI) within minutes of the onset of symptoms. However, in daily routine CT is still the preferred imaging modality for patients with acute stroke. Our purpose of this study was to determine how early and reliably ischaemic brain infarcts can be identified by CT and DWI. Three neuroradiologists, blinded to clinical signs but aware that they were dealing with stroke, analysed the CT and DWI of 31 patients with an acute ischaemic stroke. We calculated kappa-values to analyse inter-rater variability. The ratings were compared with follow-up studies showing the extent of the infarct. The combined assessment of all observers gave positive findings in 77.4% of all CT examinations, with kappa = 0.58. Areas of high signal were seen on all DWI studies by all observers (kappa = 1). Estimation of the extent of the infarct based on DWI yeilded kappa = 0.70 and that based on CT kappa = 0.39. DWI was much more reliable than CT in the detection of early ischaemic lesions and we believe that it should be used in acute ischaemic stroke before aggressive therapeutic intervention.

Stroke magnetic resonance imaging within 6 hours after onset of hyperacute cerebral ischemia.

We studied the diagnostic and prognostic value of diffusion- and perfusion-weighted magnetic resonancce imaging (DWI and PWI) for the initial evaluation and follow-up monitoring of patients with stroke that had ensued less than 6 hours previously. Further, we examined the role of vessel patency or occlusion and subsequent recanalization or persistent occlusion for further clinical and morphological stroke progression so as to define categories of patients and facilitate treatment decisions. Fifty-one patients underwent stroke magnetic resonance imaging (DWI, PWI, magnetic resonance angiography, and T2-weighted imaging) within 3.3 +/- 1.29 hours, and, of those, 41 underwent follow-up magnetic resonance imaging on day 2 and 28 on day 5. In addition, we assessed clinical scores (on the National Institutes of Health Stroke Scale, Scandinavian Stroke Scale, Barthel Index, and Modified Rankin Scale) on days 1, 2, 5, 30, and 90 and performed volumetric analysis of lesion volumes. In all, 25 patients had a proximal, 18 a distal, and 8 no vessel occlusion. Furthermore, 15 of 43 patients exhibited recanalization on day 2. Vessel occlusion was associated with a PWI-DWI mismatch on the initial magnetic resonance imaging, vessel patency with a PWI-DWI match (p < 0.0001). Outcome scores and lesion volumes differed significantly between patients experiencing recanalization and those who did not (all p < 0.0001). Acute DWI and PWI lesion volumes correlated poorly with acute clinical scores and only modestly with outcome scores. We have concluded on the basis of this study that early recanalization saves tissue at risk of ischemic infarction and results in significantly smaller infarcts and a significantly better clinical outcome. Patients with proximal vessel occlusions have a larger amount of tissue at risk, a lower recanalization rate, and a worse outcome. Urgent recanalization seems to be of utmost importance for these patients.

Feasibility and practicality of MR imaging of stroke in the management of hyperacute cerebral ischemia.

BACKGROUND AND PURPOSE: Neuroimaging techniques such as diffusion- and perfusion-weighted MR imaging have been proposed as tools for advanced diagnosis in hyperacute ischemic stroke. There is, however, substantial doubt regarding the feasibility and practicality of applying MR imaging for the diagnosis of stroke on a routine basis, especially with respect to possible delay for specific treatment such as thrombolysis. In this study, we tested whether MR imaging of stroke is safe, fast, and accurate, and whether the gain in additional information can be used in the daily routine without a loss of time and a risk of suboptimal treatment for the patient with stroke. METHODS: Between September 1997 and August 1999, 64 patients with acute ischemic stroke were recruited for MR imaging (ie, diffusion-weighted imaging, perfusion-weighted imaging, MR angiography, T2-weighted imaging) after a baseline CT was performed. We evaluated practicality and feasibility of MR imaging of stroke by analyzing the intervals between symptom onset, arrival, CT, and MR imaging. RESULTS: Sixty-four patients (mean age, 60.9 years) underwent routine CT and MR imaging within 12 hours after stroke onset (n=25, < or =3 hr; n=26, 3-6 hr; n=13, 6-12 hr). Median times to arrival, start of CT, MR imaging, and between CT and MR imaging were 1.625 hours, 2 hours, 3.875 hours, and 1 hour, respectively. Intervals between symptom onset and MR imaging (P<.005), arrival and MR imaging (P<.002), and CT and MR imaging (P=.0007) differed significantly between the early phase of the study and after November 1998, whereas the intervals between symptom onset and arrival, symptom onset and CT, and arrival and CT did not. Hemorrhage could be excluded in all; a perfusion/diffusion match or mismatch could be shown in 63 of 64 patients. CONCLUSION: Practice and experience with MR imaging in a stroke team significantly reduce the time and effort required to perform this technique and thus make 24-hour availability for MR imaging of stroke practical. Assessment of patients with hyperacute stroke is rapid and comprehensive. Image quality can be substantially improved by head immobilization and by mild sedation, if necessary.

Monitoring intravenous recombinant tissue plasminogen activator thrombolysis for acute ischemic stroke with diffusion and perfusion MRI.

BACKGROUND AND PURPOSE: Intravenous recombinant tissue plasminogen activator (rtPA) administration is an effective therapy for ischemic stroke when initiated within 3 hours and possibly up to 6 hours after symptom onset. To improve patient selection, a fast diagnostic tool that allows reliable diagnosis of hemorrhage and ischemia, vessel status, and tissue at risk at an early stage may be useful. We studied the feasibility of stroke MRI for the initial evaluation and follow-up monitoring of patients undergoing intravenous thrombolysis. METHODS: Stroke MRI (diffusion- and perfusion-weighted imaging [DWI and PWI, respectively], magnetic resonance angiography, and T2-weighted imaging) was performed before, during, or after thrombolysis and on days 2 and 5. We assessed clinical scores (National Institutes of Health Stroke Scale [NIHSS], Scandinavian Stroke Scale [SSS], Barthel Index, and Rankin scale) at days 1, 2, 5, 30, and 90. Furthermore, we performed volumetric analysis of infarct volumes on days 1, 2, and 5 as shown in PWI, DWI, and T2-weighted imaging. RESULTS: Twenty-four patients received rtPA within a mean time interval after symptom onset of 3.27 hours and stroke MRI of 3.43 hours. Vessel occlusion was present in 20 of 24 patients; 11 vessels recanalized (group 1), and 9 did not (group 2). The baseline PWI lesion volume was significantly larger (P=0.008) than outcome lesion size in group 1, whereas baseline DWI lesion volume was significantly smaller (P=0.008) than final infarct size in group 2. Intergroup outcome differed significantly for all scores at days 30 and 90 (all P<0.01). Intragroup differences were significant in group 1 for change in SSS and NIHSS between day 1 and day 30 (P=0.003) and for SSS only between day 1 and day 90 (P=0.004). CONCLUSIONS: Stroke MRI provides comprehensive prognostically relevant information regarding the brain in hyperacute stroke. Stroke MRI may be used as a single imaging tool in acute stroke to identify and monitor candidates for thrombolysis. It is proposed that stroke MRI is safe, reliable, and cost effective; however, our data do not prove this assumption. Early recanalization achieved by thrombolysis can save tissue at risk if present and may result in significantly smaller infarcts and a significantly better outcome.

Adhesion and proliferation of keratinocytes on ion beam modified polyethylene.

Polyethylene (PE) foils were modified by irradiation with Ar+ and Xe+ ions to different fluences and different physico-chemical properties of the irradiated PE were studied in relation to adhesion and proliferation of keratinocytes on the modified surface. Changes in the PE surface roughness were examined using the AFM technique, the production of conjugated double bonds and oxidized structures by UV-VIS and FTIR techniques respectively. The surface polarity was determined by measuring surface contact angle and two-point technique was used for the determination of PE sheet resistance. Adhesion and proliferation of keratinocytes was characterized using the MTT-test. The ion irradiation leads to creation of conjugated double bonds which, together with progressive carbonization, contribute to the observed decrease of sheet resistance. Oxidation of the irradiated PE surface layer during the ion implantation is observed. Besides oxidation, the PE surface polarity is affected by other factors. The observed increase of the PE surface roughness due to the ion irradiation is inversely proportional to the ion size. The adhesion and proliferation of keratinocytes on the ion irradiated PE is significantly higher than on the pristine PE. Distribution of results in keratinocyte cultivation and the number of cells is related to the ion fluence applied and to ion species as well.