Porcine wound healing in full-thickness skin defects using Integra? with and without fibrin glue with keratinocytes

BACKGROUND:

An artificial dermal matrix such as Integra (Integra Life Sciences Corporation, USA) provides a wound bed template for vascular and fibrocyte ingrowth as well as collagen remodelling. Dermal repair leads to epidermal and basement membrane regeneration. Burn wounds in particular have been shown to benefit from Integra by enhanced wound healing.

OBJECTIVE:

To evaluate the effect of fibrin glue to modify the integration of Integra in large excised cutaneous wounds. It was hypothesized that applying fibrin glue on a wound bed would reduce the time needed for matrix vascularization and incorporation of Integra and take of the cultured keratinocytes.

METHODS:

Four separate full-thickness wounds were created on the dorsum of two swine. Wound beds were randomly assigned to either application of fibrin glue or no application of fibrin glue before application of Integra. Full-thickness biopsies were performed at days 7, 14, 21, 29 and 35. On day 21, keratinocytes were applied either as sheets or aerosolized fibrin glue suspension.

RESULTS:

Histological analysis revealed a wave of inflammatory cells and early granulation tissue ingrowth into the Integra from the fascia below on day 7. Only this initial phase was augmented by application of fibrin glue to the wound bed. By day 14, most and by day 21, all of the Integra thickness was incorporated. Accelerated dermal repair proceeded from the base with new collagen deposition in Integra spaces. There was no evidence of keratinocyte engraftment, although re-epithelialization occurred at wound edges extending onto the incorporated Integra.

CONCLUSIONS:

It appears there is an acceleration of early phase (day 7 to day 21) dermal incorporation with fibrin glue application to the wound bed, perhaps secondary to increased cellular migration. Day 21 appears to be too early to apply cultured keratinocytes either as sheets or aerosolized suspension.     

Fluoroscopy cannot recognize intraoperative fracture in patients receiving 2-incision total hip arthroplasty

Intraoperative fluoroscopy is suggested as a standard procedure in 2-incision total hip arthroplasty. Between September 2003 and July 2004, 2-incision total hip arthroplasties were done in 18 hips with and another 18 hips without the use of fluoroscopy. In group 1, the anterior skin incision was initially limited to 5 cm. Fracture or instability was checked by fluoroscopy first and then the incision was enlarged to 8 cm for visualization. In group 2, incisions were made long enough to expose the surgical field. There were 2 femoral neck fractures in the fluoroscopy group. The fractures were linear in the anteromedial femoral neck and could not be detected by fluoroscopy. Such linear fractures if overlooked could result in serious complications such as fracture displacement or implant instability. Surgeons should not rely on intraoperative fluoroscopy to check implant stability, and visualization of the surgical field should not be compromised when doing minimally invasive approach for total hip arthroplasty.     

Incidence of and risk factors for acute stress disorder in children with injuries

BACKGROUND: To assess the incidence of and risk factors for Acute Stress Disorder (ASD) in children with injuries. Numerous studies have documented the increased incidence of PTSD in those initially diagnosed with ASD. PTSD symptoms cause tremendous morbidity and may persist for many years in some children. METHODS: Children hospitalized with one or more injuries were interviewed and assessed with the following: Child Stress Disorders Checklist (CSDC), Family Strains Scale, Brief Symptom Inventory (BSI) and Facial Pain Scale. RESULTS: Participants included sixty-five children (ages 7-18 years). The mechanisms of injury varied (e.g. MVC, penetrating). The mean injury severity score was 8.9 +/- 7. The mean length of hospital stay was 4.6 +/- 4.6 days. Altogether, 18 (27.7%) of participants met DSM IV criteria for ASD during their acute hospital stay. Risk factors such as level of family stress, caregiver stress, child's experience of pain, and child's age were predictive of acute stress symptoms. CONCLUSION: We have identified four risk factors of ASD that have implications for the treatment, and possibly, preventative intervention for PTSD. Further investigation and greater understanding of risk factors for ASD in children with injuries may facilitate the design of acute interventions to prevent the long-term negative outcomes of traumatic events.     

Mitochondrial Networking Protects ��-Cells From Nutrient-Induced Apoptosis

OBJECTIVE

Previous studies have reported that β-cell mitochondria exist as discrete organelles that exhibit heterogeneous bioenergetic capacity. To date, networking activity, and its role in mediating β-cell mitochondrial morphology and function, remains unclear. In this article, we investigate β-cell mitochondrial fusion and fission in detail and report alterations in response to various combinations of nutrients.

RESEARCH DESIGN AND METHODS

Using matrix-targeted photoactivatable green fluorescent protein, mitochondria were tagged and tracked in β-cells within intact islets, as isolated cells and as cell lines, revealing frequent fusion and fission events. Manipulations of key mitochondrial dynamics proteins OPA1, DRP1, and Fis1 were tested for their role in β-cell mitochondrial morphology. The combined effects of free fatty acid and glucose on β-cell survival, function, and mitochondrial morphology were explored with relation to alterations in fusion and fission capacity.

RESULTS

β-Cell mitochondria are constantly involved in fusion and fission activity that underlies the overall morphology of the organelle. We find that networking activity among mitochondria is capable of distributing a localized green fluorescent protein signal throughout an isolated β-cell, a β-cell within an islet, and an INS1 cell. Under noxious conditions, we find that β-cell mitochondria become fragmented and lose their ability to undergo fusion. Interestingly, manipulations that shift the dynamic balance to favor fusion are able to prevent mitochondrial fragmentation, maintain mitochondrial dynamics, and prevent apoptosis.

CONCLUSIONS

These data suggest that alterations in mitochondrial fusion and fission play a critical role in nutrient-induced β-cell apoptosis and may be involved in the pathophysiology of type 2 diabetes.Mitochondria mediate β-cell responses to extracellular glucose by generating ATP and initiating a cascade of events culminating in the release of insulin. It is not surprising that β-cell mitochondria have become an important target for investigations into the etiology of type 2 diabetes. Mitochondria are highly dynamic organelles whose morphology is regulated by cycles of fusion and fission, collectively termed mitochondrial dynamics (1,2). Networks are formed when mitochondria undergo fusion events that cause the compartments of participating mitochondria to become continuous. As a result, the constituents of each network share solutes, metabolites, and proteins (3–5) as well as a transmembrane electrochemical gradient (1,6). The disruption of such networks has been shown to have a profound effect on the progression of cells to apoptosis, particularly in cases where reactive oxygen species (ROS) are involved (7). As such, mitochondrial networking is thought to be a potential defense mechanism allowing for the buffering of mitochondrial ROS and calcium overload (8,9).Chronically elevated levels of glucose and fatty acid are thought to contribute to the progression of type 2 diabetes by adversely affecting β-cells and thereby causing a deterioration in insulin secretion (10). In vivo, a reduction in insulin gene expression due to reduced Pdx-1 binding has been observed in rats perifused with glucose and intralipids (11,12). In addition, exposure to high levels of glucose and/or free fatty acid has been shown to affect β-cell viability by inducing mitochondrial apoptosis and has been linked to ROS-induced mitochondrial calcium overload and damage (13). Recent studies indicate that nutrient-induced ROS increases subcellular mitochondrial membrane potential (ΔΨmt) heterogeneity and fragmentation of the mitochondrial architecture (14,15). These findings suggest that mitochondrial fragmentation-defragmentation might play a role in the effects of noxious stimuli. Although the functional significance of these changes has not been studied in β-cells, studies of mitochondrial morphology in other cells have demonstrated that the ability of mitochondria to form networks influences both ROS and calcium handling (7–9).Previous studies have reported that β-cell mitochondria form less elaborate network structures, compared with COS cells for example, and raise doubts on the existence of mitochondrial networking in these cells. Until now, technologies for examining and quantifying the ability of mitochondria to undergo fusion and fission were unavailable.In this work, we show that the densely packed appearance of mitochondria in the β-cell represents the existence of multiple juxtaposed units that do not share continuous matrix lumen but do go through frequent fusion and fission events. We further demonstrate that mitochondrial dynamics are disrupted by exposure to the combination of high fat and glucose, gradually leading to the arrest of fusion activity and complete fragmentation of the mitochondrial architecture. Inhibiting mitochondrial fission preserved mitochondrial morphology and dynamics and prevented β-cell apoptosis.     

Use of antibiotic cement-impregnated intramedullary nail in treatment of infected non-union of long bones

Background:

In cases with infected non-union, the primary step is eradication of the infection before attempting to achieve union. Release of antibiotics from the bone cement at a high concentration and its penetration to the surrounding tissues, including cortical and cancellous bone, prompted the use of antibiotic cement in the control of bone infection. The aim of this study is to summarize our experience with the use of antibiotic cement-impregnated intramedullary nail (ACIIN) for control of infection in cases of infected non-union with bone defect.

Materials and Methods:

We prospectively studied 25 cases of infected non-union (23 femora and two tibiae). There were 24 males and one female, with the mean age being 33 years (range, 21–58 years). All patients had high-velocity road traffic accidents except one patient who had farmland injury. There were seven closed fractures, one grade I compound, two grade II compound fractures, five grade IIIA compound fractures, and 10 grade IIIB compound fractures. ACIIN was used in all cases after adequate debridement. Patients were classified according to the amount of bone defect present after debridement: group 1 with bone defect <4 cm (n=13), group 2 with bone defect ≥4–<6 cm (n=7), and group 3 with bone defect ≥6 cm (n=5). Infection control was judged on the basis of discharge through the wound and laboratory parameters. All patients were followed-up, with an average follow-up time of 29 months (range, 18–40 months). The mean duration of retention of the intramedullary rod was 8 weeks (range, 6–12 weeks).

Results:

In group 1, all cases achieved infection control, with three patients achieving bone union without any need of secondary procedure. In group 2, all cases achieved infection control but the time taken was significantly longer than for group 1 (P value 0.0002). All the cases required a secondary procedure in the form of either interlocking intramedullary nailing with iliac crest bone graft or Ilizarov ring fixator application to achieve union. None of the cases in group 3 achieved infection control.

Conclusion:

ACIINs are useful for infection control in cases of infected non-union with bone defect <6 cm. In cases with defect >6 cm, other alternatives should be used.     

Influence of increasing construct constraint in the presence of posterolateral deficiency at knee replacement: A biomechanical study

When faced with posterolateral corner (PLC) deficiency, surgeons must choose a total knee replacement (TKR) construct that provides the appropriate level of constraint. This should match the internal constraint of the device to the soft tissue host laxity pattern. Little guidance is available peroperatively, with factors influencing final component choice remaining ill defined. This study aimed to quantify the effect of PLC insufficiency on the “envelope of laxity” (EoL) after TKR and the effect of increasingly component constraint upon knee behavior through a functional arc of flexion. Using computer navigation, mixed effect modeling and loaded cadaveric legs—laxity was quantified under separate states: the native knee, after implantation of a posterior stabilized (PS)‐TKR, after sectioning the lateral (fibular) collateral ligament and popliteus tendon (PS‐TKR‐PLC), and after re‐implantation with a semi‐constrained “total stabilized” knee replacement (TS‐TKR). Laxity was quantified from 0 to 110° of flexion for anterior draw, varus–valgus, and internal–external rotation. Implantation of the PS‐TKR was consistently associated with increased constraint when compared to the native knee. PLC sectioning led to significantly increased laxity during varus stress from mid to deep flexion. Revision to a TS‐TKR construct restored constraint mimicking that of the primary state but only for the arc of motion 0–90°. In a posterolateral deficient state, a fixed bearing semi‐constrained TS‐TKR restored the knee to near normal kinematics but this was only achieved from an arc of motion 0–90° of flexion. At higher flexion angles, there remained an unfavorable laxity pattern with varus stress opening. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:427–434, 2016.     

Reconstructive surgery and patients with spinal cord injury: Perioperative considerations for the plastic surgeon

Background: Patients with spinal cord injury (SCI) requiring reconstructive surgery, particularly for pressure ulcers, are ubiquitous in Plastic and Reconstructive Surgery practices. Much of the current literature focuses on operative techniques, antibiotic indications, sitting protocols, and dressing and bedding choices. Methods: This paper reviews normal neuroanatomy, outlines changes in neurophysiology observed in spinal cord injury, and addresses concepts related to perioperative care that are highly relevant but often under-emphasised. Results: Vascular disturbances such as autonomic dysreflexia and orthostatic hypotension are dangerous phenomena occurring in this patient population that, if not properly recognised and treated, may result in complications such as haematoma, flap loss, inadequate tissue perfusion, and death. The management of spasticity, deep venous thrombosis, and perioperative pain are also relevant and discussed in this paper. Conclusion: A basic understanding of these concepts is essential for the Plastic Surgeon involved in the care of patients with SCI and pressure ulcers, particularly before and after debridement or reconstruction.