Morphology and hemodynamics during vascular regeneration in critically ischemic murine skin studied by intravital microscopy techniques.

BACKGROUND: With the understanding of angiogenesis and arteriogenesis, new theories about the orchestration of these processes have emerged. The aim of this study was to develop an in vivo model that enables visualization of vascular regenerating mechanisms by intravital microscopy techniques in collateral arteriolar flap vascularity. METHODS: A dorsal skin flap (15 × 30 mm) was created in mice and fixed into a skinfold chamber to allow for assessment of morphology and microhemodynamics by intravital fluorescence microscopy (IVFM). Laser scanning confocal microscopy (LSCM) was utilized for three-dimensional reconstruction of the microvascular architecture. RESULTS: Flap tpO(2) was 5.3 ± 0.9 versus 30.5 ± 1.2 mm Hg in controls (p < 0.01). The collateral arterioles in the flap tissue were dilated (29.4 ± 5.3 µm; p < 0.01 vs. controls) and lengthened in a tortuous manner (tortuosity index 1.00 on day 1 vs. 1.35± 0.05 on day 12; p < 0.01). Functional capillary density was increased from 121.00 ± 25 to 170 ± 30 cm/cm(2) (day 12; p < 0.01) as a result of angiogenesis. Morphological evidence of angiogenesis on capillary level and vascular remodeling on arteriolar level could be demonstrated by IVFM and LSCM. CONCLUSIONS: Present intravital microscopy techniques offer unique opportunities to study structural changes and hemodynamic effects of vascular regeneration in this extended axial pattern flap model.

Initial experiences using non-cultured autologous keratinocyte suspension for burn wound closure.

Early complete wound closure and thus reduction of excessive scar formation still represent a major clinical challenge in severely burned patients. A novel concept to cover large burn wounds consists of the application of non-cultured epithelial cell suspension within the first days. Herein, we report our experiences with three patients treated with CellSpray XP. According to the amount of cell suspension required, a skin biopsy was harvested and then processed in an external laboratory. Two days later the suspension containing autologous non-cultured keratinocytes was applied using an aerosol system. All wounds healed rapidly and virtually no signs of hypertrophic scarring were observed 6 months later.

[Surgical treatment of high-voltage electrical injuries]. / Die chirurgische Behandlung von Hochspannungsverletzungen.

PURPOSE/BACKGROUND: High-voltage burns represent a challenging surgical entity. Compared to conventional burns, these injuries are characterized by an increased morbidity and worse potential for rehabilitation. The aim of the present study was to analyse the management of high-voltage injuries during the early posttraumatic period with special emphasis on the surgical procedures. PATIENTS/MATERIAL AND METHOD: We retrospectively evaluated the medical records of patients with electrical injuries treated from 1995 - 2007. A total of 61 patients (57 men, 4 females, mean age: 34 +/- 13 years) with high-voltage burns was included for analysis. RESULTS: The majority of high-voltage burns was work-related (75 %). The mean total burn area was 35 % of the total body surface, with a mean of 29 % deep burns. An average of 4.8 +/- 4 operations were performed per patient (range: 1 - 23 operations). Surgical procedures included repeated debridement/necrectomy (100 % of all patients), early escharotomy/fasciotomy (47.5 %), and amputations (18 %). 14 patients (23 %) underwent reconstructive surgery using either local or free flaps. The mortality rate was 15 %. CONCLUSION: The surgical management of high-voltage burns is characterised by repetitive debridements and necrectomies. Despite an aggressive approach to remove necrotic tissue, the mortality in this type of injury is considerably high. Limb salvage may be achieved with the use of free microvascular flaps. However, an amputation of necrotic extremities must be considered in the copresence of septic complications.

The influence of local and systemic preconditioning on oxygenation, metabolism and survival in critically ischaemic skin flaps in pigs.

Stress proteins represent a group of highly conserved intracellular proteins that provide adaptation against cellular stress. The present study aims to elucidate the stress protein-mediated effects of local hyperthermia and systemic administration of monophosphoryl lipid A (MPL) on oxygenation, metabolism and survival in bilateral porcine random pattern buttock flaps. Preconditioning was achieved 24h prior to surgery by applying a heating blanket on the operative site (n = 5), by intravenous administration of MPL at a dosage of 35 microg/kg body weight (n = 5) or by combining the two (n = 5). The flaps were monitored with laser Doppler flowmetry, polarographic microprobes and microdialysis until 5h postoperatively. Semiquantitative immunohistochemistry was performed for heat shock protein 70 (HSP70), heat shock protein 32 (also termed haem oxygenase-1, HO-1), and inducible nitrc oxide synthase (iNOS). The administration of MPL increased the impaired microcirculatory blood flow in the proximal part of the flap and partial oxygen tension in the the distal part by approximately 100% each (both P<0.05), whereas both variables remained virtually unaffected by local heat preconditioning. Lactate/pyruvate (L/P) ratio and glycerol concentration (representing cell membrane disintegration) in the distal part of the flap gradually increased to values of approximately 500 mmol/l and approximately 350 micromol/l, respectively (both P<0.01), which was substantially attenuated by heat application (P<0.01 for L/P ratio and P<0.05 for glycerol) and combined preconditioning (P<0.01 for both variables), whereas the effect of MPL was less marked (not significant). Flap survival was increased from 56% (untreated animals) to 65% after MPL (not significant), 71% after heat application (P<0.05) and 78% after both methods of preconditioning (P<0.01). iNOS and HO-1 were upregulated after each method of preconditioning (P<0.05), whereas augmented HSP70 staining was only observed after heat application (P<0.05). We conclude that local hyperthermia is more effective in preventing flap necrosis than systemic MPL administration because of enhancing the cellular tolerance to hypoxic stress, which is possibly mediated by HSP70, whereas some benefit may be obtained with MPL due to iNOS and HO-1-mediated improvement in tissue oxygenation.

Extraocular eye muscles in human fetuses with craniofacial malformations: anatomical findings and clinical relevance.

Anomalies of the extraocular muscles have been suspected to be present frequently in patients with craniofacial malformations. We studied the extraocular musculature in the orbits of 15 anencephalic human fetuses between the 5th and 10th months after gestation, and in one fetus with an occipital meningocele and a large defect of the left cranial base. The findings were compared to those in nine normal age-matched fetuses. All malformed fetuses exhibited special features of the levator palpebrae superioris muscle, either its absence, an anomaly of the muscle belly, or an anomalous insertion. In addition, deficient or aberrant muscle bellies of the oblique and rectus muscles were found. In anencephaly, the frontal bone is condensed, forming narrowed orbital cavities with hypotelorism. Frequent disturbance of extraocular muscle development in fetuses with craniofacial malformations is implicated. The presented specimens are examples of extreme variants of cranial and craniofacial malformation syndromes. Thus, similar findings of extraocular muscles might also be regularly found in clinically relevant craniofacial malformations. This would force new considerations about diagnostic and therapeutic approaches to patients with craniofacial malformations.

Levator palpebrae superioris muscle in human fetuses: anatomical findings and their clinical relevance.

Accessory medial muscular bellies of the levator palpebrae superioris muscle and broad lateral insertion of its aponeurosis into tissue near the lacrimal gland have been reported as rare variations in adults. The anatomy of this muscle was studied in orbits of ten human fetuses between the 5th and 10th months of gestation. In each of the dissected orbits, the levator palpebrae superioris muscle had a broad lateral insertion into the capsule of the lacrimal gland or the periorbita, in this period of development. In addition, medial accessory muscles of the levator or singular muscle fibers within fibrous bands that inserted near the trochlear region and the medial portion of the upper eyelid were present in 70% of the fetuses, either unilaterally or bilaterally. These findings demonstrate new unreported aspects of levator palpebrae superioris development and morphology. Our findings suggest that an initial broad anterior primary anlage of the muscle is followed by secondary atrophy of lesser used marginal portions of this muscle, which are replaced by delicate connective tissue. These findings might force new considerations about diagnostic and therapeutic approaches to congenital mobility disorders of the levator palpebrae superioris muscle, such as blepharoptosis or eyelid retraction. The clinical relevance of our results are discussed along with a review of the embryogenesis of extraocular muscles and soft tissue of the orbit.

Improved skin flap survival after local heat preconditioning in pigs.

BACKGROUND: Preconditioning induces the expression of heat shock proteins (HSPs), which can help a cell survive an acute episode of stress. Similar to the induction of HSP expression, the cell protection is independent of the type of stress. The aim of this study was to test in a large, randomized animal model, if skin flap survival may be improved by local heat preconditioning and induction of HSP 70. MATERIALS AND METHODS: Twenty-four hours before surgery, a heating blanket was laid on the buttocks of large white pigs. In the preconditioned group (n = 6), the blanket was warmed up to 43 degrees C for 3 x 30 min, whereas it was kept at room temperature in between the heating episodes as well as in the control animals (n = 6). A random pattern skin flap was raised on both sides of the buttocks. Flap survival was measured clinically. Induction of HSP and apoptosis were assessed quantitatively by immunohistochemistry and TUNEL assay, respectively. RESULTS: Preconditioning reduced flap necrosis from 40 +/- 8% of the total flap surface to 7 +/- 14% (P < 0.01). Induction of HSP was significantly higher in the experimental group (79 +/- 12% versus 42 +/- 13%, P < 0.01), whereas apoptosis in healthy flap tissue was reduced from 30 +/- 11 to 11 +/- 6 cells/visual field (P < 0.01). CONCLUSION: In the present study, necrosis and apoptosis rate of skin flaps could be reduced significantly due to local heat preconditioning. Our results suggest that ischemia-related wound healing complications could be diminished with local heat application, a most simple and least invasive method of preconditioning.