Ambient intelligence-based monitoring of staff and patient activity in the intensive care unit.

BACKGROUND: Caregiver workload in the ICU setting is difficult to numerically quantify. Ambient Intelligence utilises computer vision-guided neural networks to continuously monitor multiple datapoints in video feeds, has become increasingly efficient at automatically tracking various aspects of human movement. OBJECTIVES: To assess the feasibility of using Ambient Intelligence to track and quantify allpatient and caregiver activity within a bedspace over the course of an ICU admission and also to establish patient specific factors, and environmental factors such as time ofday, that might contribute to an increased workload in ICU workers. METHODS: 5000 images were manually annotated and then used to train You Only LookOnce (YOLOv4), an open-source computer vision algorithm. Comparison of patientmotion and caregiver activity was then performed between these patients. RESULTS: The algorithm was deployed on 14 patients comprising 1762800 framesof new, untrained data. There was a strong correlation between the number ofcaregivers in the room and the standardized movement of the patient (p < 0.0001) withmore caregivers associated with more movement. There was a significant difference incaregiver activity throughout the day (p < 0.05), HDU vs. ICU status (p < 0.05), delirious vs. non delirious patients (p < 0.05), and intubated vs. not intubated patients(p < 0.05). Caregiver activity was lowest between 0400 and 0800 (average .71 ± .026caregivers per hour) with statistically significant differences in activity compared to 0800-2400 (p < 0.05). Caregiver activity was highest between 1200 and 1600 (1.02 ± .031 caregivers per hour) with a statistically significant difference in activity comparedto activity from 1600 to 0800 (p < 0.05). The three most dominant predictors of workeractivity were patient motion (Standardized Dominance 78.6%), Mechanical Ventilation(Standardized Dominance 7.9%) and Delirium (Standardized Dominance 6.2%). CONCLUSION: Ambient Intelligence could potentially be used to derive a single standardized metricthat could be applied to patients to illustrate their overall workload. This could be usedto predict workflow demands for better staff deployment, monitoring of caregiver workload, and potentially as a tool to predict burnout.

Intraoperative Hemifacial Composite Flap Perfusion Assessment Using Spatial Frequency Domain Imaging: A Pilot Study in Preparation for Facial Transplantation.

BACKGROUND: Vascularized composite allotransplantation represents an important advancement in the field of reconstructive microsurgery and has continued to increase in popularity. The significant clinical morbidity associated with flap failure represents an important barrier to even more widespread use of these techniques. Early identification of vascular compromise has been associated with a higher salvage rate, yet most surgeons rely only on clinical assessment intraoperatively. Spatial frequency domain imaging (SFDI) presents a noncontact, objective measurement of tissue oxygenation over a large field of view. This study aims to evaluate the use of SFDI technology in hemifacial composite flap compromise as could occur during facial transplant. METHODS: Six composite hemifacial flaps were created in three 35-kg Yorkshire pigs and continuously imaged using SFDI before, during, and after 15-minute selective vascular pedicle occlusion. Arterial and venous clamping trials were performed for each flap. Changes in oxyhemoglobin concentration, deoxyhemoglobin concentration, and total hemoglobin were quantified over time. RESULTS: The SFDI successfully measured changes in oxygenation parameters in all 6 composite tissue flaps. Significant changes in oxyhemoglobin, deoxyhemoglobin, and total hemoglobin were seen relative to controls. Early and distinct patterns of alteration were noted in arterial and in venous compromise relative to one another. CONCLUSIONS: The need for noninvasive, reliable assessment of composite tissue graft viability is apparent, given the morbidity associated with flap failure. The results of this study suggest that SFDI technology shows promise in providing intraoperative guidance with regard to pedicle vessel integrity during reconstructive microsurgery.

A Budget Impact Analysis of Newly Available Hepatitis C Therapeutics and the Financial Burden on a State Correctional System.

Hepatitis C virus (HCV) infection continues to disproportionately affect incarcerated populations. New HCV drugs present opportunities and challenges to address HCV in corrections. The goal of this study was to evaluate the impact of the treatment costs for HCV infection in a state correctional population through a budget impact analysis comparing differing treatment strategies. Electronic and paper medical records were reviewed to estimate the prevalence of hepatitis C within the Rhode Island Department of Corrections. Three treatment strategies were evaluated as follows: (1) treating all chronically infected persons, (2) treating only patients with demonstrated fibrosis, and (3) treating only patients with advanced fibrosis. Budget impact was computed as the percentage of pharmacy and overall healthcare expenditures accrued by total drug costs assuming entirely interferon-free therapy. Sensitivity analyses assessed potential variance in costs related to variability in HCV prevalence, genotype, estimated variation in market pricing, length of stay for the sentenced population, and uptake of newly available regimens. Chronic HCV prevalence was estimated at 17% of the total population. Treating all sentenced inmates with at least 6 months remaining of their sentence would cost about $34 million-13 times the pharmacy budget and almost twice the overall healthcare budget. Treating inmates with advanced fibrosis would cost about $15 million. A hypothetical 50% reduction in total drug costs for future therapies could cost $17 million to treat all eligible inmates. With immense costs projected with new treatment, it is unlikely that correctional facilities will have the capacity to treat all those afflicted with HCV. Alternative payment strategies in collaboration with outside programs may be necessary to curb this epidemic. In order to improve care and treatment delivery, drug costs also need to be seriously reevaluated to be more accessible and equitable now that HCV is more curable.

Near-infrared imaging for the assessment of anastomotic patency, thrombosis, and reperfusion in microsurgery: a pilot study in a porcine model.

BACKGROUND: Advances in microsurgical techniques have increased the use of free tissue transfer. Methods of intraoperative flap perfusion assessment, however, still rely primarily on subjective evaluation of traditional clinical parameters. Anastomotic thrombosis, if not expeditiously identified and revised, can result in flap loss with significant associated morbidity. This study aims to evaluate the use of near-infrared (NIR) fluorescence imaging in the assessment of microsurgical anastomotic patency, thrombosis, and vascular revision. MATERIALS AND METHODS: A model of pedicle thrombosis was created using bilateral abdominal flaps isolated on deep superior epigastric vascular pedicles in four Yorkshire pigs. Following flap elevation, microvascular arterial and venous anastomoses were performed unilaterally, preserving an intact contralateral control flap. Thrombosis was induced at the arterial anastomosis site using ferric chloride, and both flaps imaged using NIR fluorescence angiography. The thrombosed vascular segments were subsequently excised and new anastomoses performed to restore flow. Follow-up imaging of both flaps was then obtained to confirm patency using fluorescence imaging technology. RESULTS: Pedicled abdominal flaps were created and successful anastomotic thrombosis was induced unilaterally in each pig. Fluorescence imaging technology identified large decreases in tissue perfusion of the thrombosed flap within 2 minutes. After successful revision anastomosis, NIR imaging demonstrated dramatic increase in flow to the reconstructed flap, but intensity did not return to pre-thrombosis levels. CONCLUSIONS: Early identification of anastomotic thrombosis is important in successful free tissue transfer. Real-time, intraoperative evaluation of flap perfusion, anastomotic thrombosis, and successful revision can be performed using NIR fluorescence imaging.

Properties of meshes used in hernia repair: a comprehensive review of synthetic and biologic meshes.

BACKGROUND: Data on the mechanical properties of the adult human abdominal wall have been difficult to obtain rendering manufacture of the ideal mesh for ventral hernia repair a challenge. An ideal mesh would need to exhibit greater biomechanical strength and elasticity than that of the abdominal wall. The aim of this study is to quantitatively compare the biomechanical properties of the most commonly used synthetic and biologic meshes in ventral hernia repair and presents a comprehensive literature review. METHODS: A narrative review of the literature was performed using the PubMed database spanning articles from 1982 to 2012 including a review of company Web sites to identify all available information relating to the biomechanical properties of various synthetic and biologic meshes used in ventral hernia repair. RESULTS: There exist differences in the mechanical properties and the chemical nature of different meshes. In general, most synthetic materials have greater stiffness and elasticity than what is required for abdominal wall reconstruction; however, each exhibits unique properties that may be beneficial for clinical use. On the contrary, biologic meshes are more elastic but less stiff and with a lower tensile strength than their synthetic counterparts. CONCLUSIONS: The current standard of practice for the treatment of ventral hernias is the use of permanent synthetic mesh material. Recently, biologic meshes have become more frequently used. Most meshes exhibit biomechanical properties over the known abdominal wall thresholds. Augmenting strength requires increasing amounts of material contributing to more stiffness and foreign body reaction, which is not necessarily an advantage.

Disparity between reported and measured patient weight: can it affect planning in breast reduction surgery?

BACKGROUND: Patient weights are frequently used in surgery for essential calculations including preoperative surgical planning, dosing of medications, and qualification for insurance reimbursement. Often, there is a disparity between patient-reported and actual measured weights. This study examines differences between self-reported and measured weights and implications in breast reduction surgery. METHODS: A review was performed of 197 consecutive women who presented for breast surgery at an academic institution. Self-reported weights were recorded during the initial encounter, and the patients were subsequently weighed on the same day. A paired t-test was used to compare the self-reported and actual measured weights and stratified analysis performed based on body mass index (BMI). The Schnur sliding scale was used to estimate resection weights for reduction mammaplasty. RESULTS: The overall mean difference in reported and measured weight was 3.0 lbs standard deviation (SD) 8.9 (P < 0.0001) with a maximum overestimation of 25 lb and underestimation of 80 lb. Statistically significant differences were found when stratified analysis was performed based on BMI as mean differences in the overweight (BMI 25-30) and obese (BMI > 30) groups were 1.7 lb SD 5.5 (P < 0.026) and 4.9 lbs SD 11.8 (P < 0.0002), respectively. Significant differences in calculated breast reduction resection weights, based on the Schnur sliding scale, were also found when comparing self-reported and measured weights in all groups. CONCLUSIONS: Significant disparities between self-reported and measured weights were identified in patients presenting for breast surgery. These differences can influence important calculations of resection weights for breast reduction surgery. These differences may also affect dosing of medications and preoperative planning.

Effects of statins on ischemia-reperfusion complications in breast free flaps.

BACKGROUND: Administration of statins or other cardiovascular medications (CVMs) could potentially protect against the development of ischemia-reperfusion (I/R) injury in free flap reconstruction. The aim of this study was to examine whether the use of statins and other CVMs decreased the rate of I/R injury in autologous free flap breast reconstruction. METHODS: Retrospective chart review was performed on women who had undergone mastectomy and autologous free flap breast reconstruction between 2004 and 2010. Patient characteristics, use of statin and/or CVMs, and I/R-related complications were ascertained. Multivariable logistic regression was used to identify associations between independent risk factors and specific complications. RESULTS: There were 702 free flap breast reconstructions included in this study; 45 performed in patients on statins, 70 in patients on CVMs, and 38 in patients on both. Overall complication rate in patients on statins and patients on CVMs was significantly higher than those not on any medication (46.7% versus 31.5%, P=0.037 and 45.7% versus 31.5%, P=0.017, respectively). When I/R complications were pooled, there were no significant differences between patients not on any medications and those on statins (P=0.26), CVMs (P=0.18), and both (P=0.83.) CONCLUSIONS: Although there may be theoretical pharmacologic benefits of statins and/or CVMs to reduce the incidence of IR injury in autologous free flap breast reconstruction, the results of this study showed no clear advantages when these drugs were used.

Evaluation of wait times for patients seeking cosmetic and reconstructive breast surgery.

BACKGROUND: Patients seeking cosmetic or reconstructive procedures in plastic surgery typically face significant wait times for consultations. Little attention has been given to potential disparities in wait times between elective cosmetic and reconstructive procedures. In this initial pilot study, we audited a broad sample of plastic surgery offices within a single state for wait times in initial consultations for both breast reconstruction and breast augmentation. METHODS: A sample of board-certified plastic surgeons was audited from the American Society of Plastic Surgeons (ASPS) Web site that listed both cosmetic and reconstructive breast surgery. Scripted patient telephone calls were made to 67 plastic surgery clinics within a single state on May 2012. Two calls separated by 7 days were made to each office by the same actor seeking an initial appointment for either breast reconstruction or breast augmentation. Wait times were calculated from the date of the call until the date of appointment offered. RESULTS: There were 72 paired calls completed on 36 plastic surgery clinics. Significant disparities in appointment wait times existed between elective cosmetic versus reconstructive procedures (P = 0.02). Mean wait times for breast reconstruction consultation (26.1 days) were significantly longer than mean consultation wait times for breast augmentation (20.9 days). Interestingly, 17.9% of offices contacted no longer perform certain procedures currently advertised on the ASPS Web site. CONCLUSIONS: Disparities exist in access to care between patients seeking elective breast augmentation and reconstruction after mastectomy. Patients seeking breast augmentation have more rapid access to plastic surgeons. This study did not evaluate possible explanations for the observed differences. Potential causes may include physician preference and compensation benefits for cosmetic procedures.

STAT6-targeting antisense oligonucleotides against solitary fibrous tumor.

Solitary fibrous tumor (SFT) is a rare, non-hereditary soft tissue sarcoma thought to originate from fibroblastic mesenchymal stem cells. The etiology of SFT is thought to be due to an environmental intrachromosomal gene fusion between NGFI-A-binding protein 2 (NAB2) and signal transducer and activator protein 6 (STAT6) genes on chromosome 12, wherein the activation domain of STAT6 is fused with the DNA-binding domain of NAB2 resulting in the oncogenesis of SFT. All NAB2-STAT6 fusion variations discovered in SFTs contain the C-terminal of STAT6 transcript, and thus can serve as target site for antisense oligonucleotides (ASOs)-based therapies. Indeed, our in vitro studies show the STAT6 3' untranslated region (UTR)-targeting ASO (ASO 993523) was able to reduce expression of NAB2-STAT6 fusion transcripts in multiple SFT cell models with high efficiency (half-maximal inhibitory concentration: 116-300 nM). Encouragingly, in vivo treatment of SFT patient-derived xenograft mouse models with ASO 993523 resulted in acceptable tolerability profiles, reduced expression of NAB2-STAT6 fusion transcripts in xenograft tissues (21.9%), and, importantly, reduced tumor growth (32.4% decrease in tumor volume compared with the untreated control). Taken together, our study established ASO 993523 as a potential agent for the treatment of SFTs.

Near-infrared imaging of face transplants: are both pedicles necessary?

BACKGROUND: Facial transplantation is a complex procedure that corrects severe facial defects due to traumas, burns, and congenital disorders. Although face transplantation has been successfully performed clinically, potential risks include tissue ischemia and necrosis. The vascular supply is typically based on the bilateral neck vessels. As it remains unclear whether perfusion can be based off a single pedicle, this study was designed to assess perfusion patterns of facial transplant allografts using near-infrared (NIR) fluorescence imaging. METHODS: Upper facial composite tissue allotransplants were created using both carotid artery and external jugular vein pedicles in Yorkshire pigs. A flap validation model was created in n = 2 pigs and a clamp occlusion model was performed in n = 3 pigs. In the clamp occlusion models, sequential clamping of the vessels was performed to assess perfusion. Animals were injected with indocyanine green and imaged with NIR fluorescence. Quantitative metrics were assessed based on fluorescence intensity. RESULTS: With NIR imaging, arterial perforators emitted fluorescence indicating perfusion along the surface of the skin. Isolated clamping of one vascular pedicle showed successful perfusion across the midline based on NIR fluorescence imaging. This perfusion extended into the facial allograft within 60 s and perfused the entire contralateral side within 5 min. CONCLUSIONS: Determination of vascular perfusion is important in microsurgical constructs as complications can lead to flap loss. It is still unclear if facial transplants require both pedicles. This initial pilot study using intraoperative NIR fluorescence imaging suggests that facial flap models can be adequately perfused from a single pedicle.

Patient involvement in the decision-making process improves satisfaction and quality of life in postmastectomy breast reconstruction.

BACKGROUND: The patient-physician relationship has evolved from the paternalistic, physician-dominant model to the shared-decision-making and informed-consumerist model. The level of patient involvement in this decision-making process can potentially influence patient satisfaction and quality of life. In this study, patient-physician decision models are evaluated in patients undergoing postmastectomy breast reconstruction. METHODS: All women who underwent breast reconstruction at an academic hospital from 1999-2007 were identified. Patients meeting inclusion criteria were mailed questionnaires at a minimum of 1 y postoperatively with questions about decision making, satisfaction, and quality of life. RESULTS: There were 707 women eligible for our study and 465 completed surveys (68% response rate). Patients were divided into one of three groups: paternalistic (n = 18), informed-consumerist (n = 307), shared (n = 140). There were differences in overall general satisfaction (P = 0.034), specifically comparing the informed group to the paternalistic group (66.7% versus 38.9%, P = 0.020) and the shared to the paternalistic group (69.3% versus 38.9%, P = 0.016). There were no differences in aesthetic satisfaction. There were differences found in the SF-12 physical component summary score across all groups (P = 0.033), and a difference was found between the informed and paternalistic groups (P < 0.05). There were no differences in the mental component score (P = 0.42). CONCLUSIONS: Women undergoing breast reconstruction predominantly used the informed model of decision making. Patients who adopted a more active role, whether using an informed or shared approach, had higher general patient satisfaction and physical component summary scores compared with patients whose decision making was paternalistic.

A novel pilot study using spatial frequency domain imaging to assess oxygenation of perforator flaps during reconstructive breast surgery.

INTRODUCTION: Although various methods exist for monitoring flaps during reconstructive surgery, surgeons primarily rely on assessment of clinical judgment. Early detection of vascular complications improves rate of flap salvage. Spatial frequency domain imaging (SFDI) is a promising new technology that provides oxygenation images over a large field of view. The goal of this clinical pilot study is to use SFDI in perforator flap breast reconstruction. METHODS: Three women undergoing unilateral breast reconstruction after mastectomy were enrolled for our study. The SFDI system was deployed in the operating room, and images acquired over the course of the operation. Time points included images of each hemiabdominal skin flap before elevation, the selected flap after perforator dissection, and after microsurgical transfer. RESULTS: Spatial frequency domain imaging was able to measure tissue oxyhemoglobin concentration (ctO2Hb), tissue deoxyhemoglobin concentration, and tissue oxygen saturation (stO2). Images were created for each metric to monitor flap status and the results quantified throughout the various time points of the procedure. For 2 of 3 patients, the chosen flap had a higher ctO2Hb and stO2. For 1 patient, the chosen flap had lower ctO2Hb and stO2. There were no perfusion deficits observed based on SFDI and clinical follow-up. CONCLUSIONS: The results of our initial human pilot study suggest that SFDI has the potential to provide intraoperative oxygenation images in real-time during surgery. With the use of this technology, surgeons can obtain tissue oxygenation and hemoglobin concentration maps to assist in intraoperative planning; this can potentially prevent complications and improve clinical outcome.

Reduction of Tumor Growth with RNA-Targeting Treatment of the NAB2-STAT6 Fusion Transcript in Solitary Fibrous Tumor Models.

Solitary fibrous tumor (SFT) is a rare soft-tissue sarcoma. This nonhereditary cancer is the result of an environmental intrachromosomal gene fusion between NAB2 and STAT6 on chromosome 12, which fuses the activation domain of STAT6 with the repression domain of NAB2. Currently there is not an approved chemotherapy regimen for SFTs. The best response on available pharmaceuticals is a partial response or stable disease for several months. The purpose of this study is to investigate the potential of RNA-based therapies for the treatment of SFTs. Specifically, in vitro SFT cell models were engineered to harbor the characteristic NAB2-STAT6 fusion using the CRISPR/SpCas9 system. Cell migration as well as multiple cancer-related signaling pathways were increased in the engineered cells as compared to the fusion-absent parent cells. The SFT cell models were then used for evaluating the targeting efficacies of NAB2-STAT6 fusion-specific antisense oligonucleotides (ASOs) and CRISPR/CasRx systems. Our results showed that fusion specific ASO treatments caused a 58% reduction in expression of fusion transcripts and a 22% reduction in cell proliferation after 72 h in vitro. Similarly, the AAV2-mediated CRISPR/CasRx system led to a 59% reduction in fusion transcript expressions in vitro, and a 55% reduction in xenograft growth after 29 days ex vivo.

Bone flap perfusion assessment using near-infrared fluorescence imaging.

BACKGROUND: Microsurgical vascularized bone flaps are a versatile technique for reconstructing large bone defects. However, the assessment of perfusion is challenging, because clinical examination is difficult intraoperatively and often not possible postoperatively. Therefore, it is important to develop techniques to assess the perfusion of vascularized bone flaps and potentially improve the surgical outcomes. Near-infrared (NIR) fluorescence imaging has previously been shown to provide real-time, intraoperative evaluation of vascular perfusion. The present pilot study investigated the ability of NIR imaging to assess the perfusion of vascularized bone flaps. METHODS: Vascularized bone flaps were created in female Yorkshire pigs using well-established models for porcine forelimb osteomyocutaneous flap allotransplantation (n = 8) and hindlimb fibula flaps (n = 8). Imaging of the bone flaps was performed during harvest using the FLARE intraoperative fluorescence imaging system after systemic injection of indocyanine green. Perfusion was also assessed using the standard of care by clinical observation and Doppler ultrasonography. NIR fluorescence perfusion assessment was confirmed by intermittent clamping of the vascular pedicle. RESULTS: NIR fluorescence imaging could identify bone perfusion at the cut end of the osteotomy site. When the vascular pedicle was clamped or ligated, NIR imaging demonstrated no fluorescence when injected with indocyanine green. With clamp removal, the osteotomy site emitted fluorescence, indicating bone perfusion. The results using fluorescence imaging showed 100% agreement with the clinical observation and Doppler findings. CONCLUSIONS: Vascularized bone transfers have become an important tool in reconstructive surgery; however, no established techniques are available to adequately assess perfusion. The results of our pilot study have indicated that NIR imaging can provide real-time, intraoperative assessment of bone perfusion.

Face transplant perfusion assessment using near-infrared fluorescence imaging.

BACKGROUND: Composite tissue allografts (CTAs) including partial face transplantation have been achieved clinically. However, risks of complications including tissue ischemia, rejection, and transplant failure are significant. Safe and effective techniques to assess perfusion are needed to decrease complications in composite tissue flaps. Near-infrared (NIR) fluorescence imaging has been previously shown to provide a real-time, intraoperative evaluation of perfusion. This study investigates the use of NIR imaging in partial face CTA harvest. METHODS: We created hemifacial CTAs (n = 8) using an established porcine model. This included ear cartilage, nerve, lymphoid tissue, muscle, and skin with perfusion by the carotid artery and external jugular vein. We injected animals systemically with indocyanine green and obtained NIR fluorescence images simultaneously with color video. In addition, we assessed the elevated hemifacial flaps using standard of care (i.e., clinical examination and Doppler). RESULTS: Flap design was facilitated by NIR imaging with localization of perforators to the hemifacial CTA flap. In particular, an arterial and venous phase could be clearly identified. We assessed perfusion of the flap by NIR fluorescence intensity after injection of indocyanine green. Sequential clamping of the artery and vein confirmed correlation of perfusion deficits with NIR imaging as well as with clinical examination and Doppler. CONCLUSIONS: Evaluation and assessment of perfusion are important in facial transplantation. The results from our pilot study indicate that NIR imaging has the capability to assess perfusion of partial facial CTAs. This emergent technology shows promise in assessing tissue perfusion in a composite flap.

Intestinal alkaline phosphatase is a gut mucosal defense factor maintained by enteral nutrition.

Under conditions of starvation and disease, the gut barrier becomes impaired, and trophic feeding to prevent gut mucosal atrophy has become a standard treatment of critically ill patients. However, the mechanisms responsible for the beneficial effects of enteral nutrition have remained a mystery. Using in vitro and in vivo models, we demonstrate that the brush-border enzyme, intestinal alkaline phosphatase (IAP), has the ability to detoxify lipopolysaccharide and prevent bacterial invasion across the gut mucosal barrier. IAP expression and function are lost with starvation and maintained by enteral feeding. It is likely that the IAP silencing that occurs during starvation is a key component of the gut mucosal barrier dysfunction seen in critically ill patients.

A novel murine island skin flap for ischemic preconditioning.

BACKGROUND: Ischemia reperfusion injury is a well-known phenomenon affecting skin flap viability. One method to improve flap viability is ischemic preconditioning. Previous murine flap models used random flaps. We developed a single pedicle island skin flap which allows us to create true ischemia by clamping the single pedicle. Our first aim was to describe a novel murine skin flap model with a definable, reproducible injury. Our second aim was to test the usefulness of this model by demonstrating mitigation of injury via ischemic preconditioning. MATERIALS AND METHODS: Dorsal lateral thoracic artery pedicle island skin flaps (3.5 x 1.5 cm) were elevated in 39 male C57/BL6 mice: a Control group (n = 7), 10 h of ischemia (n = 21), and Preconditioning (2 cycles of 20 min ischemia: 20 minutes reperfusion) + 10-h ischemia (n = 11). After flap elevation, a silicon sheet barrier was placed. The axial pedicles were occluded, and the flaps were inset with 6-0 prolene. In all mice, ischemia was followed by 1 wk of reperfusion. At 1 wk, percent necrosis was measured and an analysis of variance was performed. RESULTS: The percent of flap necrosis was 1.1% +/- 1.11% in controls. Animals that were subjected to 10 h of ischemia developed 33.14% +/- 7.23% necrosis. Preconditioned animals that underwent 10 h of ischemia demonstrated a 43% reduction in necrosis (18.82% +/- 5.68%). There was a statistically significant difference among all groups (P < or = 0.001). CONCLUSION: Rat models have been the standard for skin flap experiments. We have developed a novel murine single pedicle island skin flap model with reproducible injury. This model has numerous advantages, including ease of handling, low cost, appropriateness for biomedical studies, and the availability of genetically altered animals. We also confirmed this model's usefulness in a study of mitigation of ischemia reperfusion injury through ischemic preconditioning.

A high-throughput model for fat graft assessment.

BACKGROUND AND OBJECTIVES: Current fat-graft animal models require weeks, to months, for results. The purpose of this study was to develop a model for the rapid identification of adipocyte protectants, using apoptosis-specific fluorescence. The goal of our model was to predict long-term fat graft survival within a 10-day period. STUDY DESIGN/MATERIALS AND METHODS: Human fat was obtained from liposuction aspirates, washed with saline, and centrifuged at 200g. The fat was then treated with one of four agents: P188, polyethylene glycol (PEG 8000), lipoic acid (LA), or saline control. Fat lobules were explanted over a 10-day period, and then at six weeks. The explanted fat was measured for apoptosis. Samples were weighed, sent for histology, measured for DNA content, and examined using confocal microscopy. RESULTS: Fat-grafts demonstrated variable apoptosis over the 10-day period. P188 and LA treated samples demonstrated 11-28% less apoptosis during early engraftment than saline treated controls. This early reduction in apoptosis correlated to a approximately 20% reduction in reabsorption by weight six weeks later. P188 and LA samples demonstrated three-times higher DNA content by PICO green analysis when compared to saline controls. PEG 8000 treated samples demonstrated 11% more apoptosis than saline. PEG 8000 treated samples demonstrated an approximately 10% higher level of reabsorption by weight, and two-times higher levels of DNA. Histology of treated samples at six weeks showed architecturally normal fat in P188 and LA treated fat; whereas PEG 8000 had high levels of inflammatory infiltrates, and saline had large amounts of fibrosis. CONCLUSIONS: This model of fat-grafting and early apoptosis can be used to screen agents and grafting methods and predict long-term graft survival. We show that levels of apoptosis within ten days correlate with weight, DNA, and histology, at six weeks. Using this model, long-term adipocyte survival and graft take can be predicted during the first 10 days post-implantation.

Gender disparity in cardiac procedures and medication use for acute myocardial infarction.

OBJECTIVE: Determine if gender bias is present in contemporary management of acute myocardial infarction (AMI). BACKGROUND: Despite major advances in medicine, disparities in healthcare still persist. Previous studies on gender bias in the diagnosis and treatment of AMI are inconsistent and may not represent more contemporary practice. METHODS AND RESULTS: Data were collected from the Minnesota Heart Survey, a population-based study of patients presenting with AMI in 2001-02. In-hospital diagnostic and therapeutic approaches were compared between women and men using logistic regression models. We identified 1242 women and 1378 men with an AMI defined by either positive cardiac biomarkers or ST-elevation on electrocardiogram. There were no differences in the prescription of aspirin, beta-blockers, ACE inhibitors or angiotensin receptor blockers. Women were 46% less likely than men to undergo investigative coronary angiography [OR = 0.54 (0.45-0.64)]. After accounting for confounders, women remained less likely to be referred for angiography [OR = 0.73 (0.57-0.94)]. Revascularization rates, were similar between women and men [OR = 0.96 (0.72-1.28)]. However, women were more likely to undergo PCI [OR = 1.41 (1.07-1.86)] whereas men were more likely to have coronary artery bypass grafting (CABG) [OR = 0.57 (0.39-0.84)]. When severity of coronary artery disease (CAD) was incorporated into the model, gender no longer influenced the modality of coronary revascularization. CONCLUSIONS: There is no evidence of gender bias in the pharmacologic treatment of AMI. Evidence of gender bias persists in the referral of patients for coronary angiography but not in the subsequent use of coronary revascularization.