Assessing the influence of rural residence and economic distress on lower extremity risk stratification among diabetic foot ulcer patients utilizing the Wound, Ischemia, and Foot Infection (WIfI) classification system.

OBJECTIVE: Diabetic foot ulcers (DFU) are a major sequela of uncontrolled diabetes with a high risk of adverse outcomes. Poor DFU outcomes disproportionately impact patients living in rural and economically distressed communities with lack of access to consistent, quality care. This study aimed to analyze the risk of geographic and economic disparities, including rural status and county economic distress, on the disease burden of DFU at presentation utilizing the SVS WIfI classification system. METHODS: We conducted a retrospective review of 454 patients diagnosed with a DFU from 2011 to 2020 at a single institution's inpatient and outpatient wound care service. Patients >18 years old, with type II diabetes mellitus, and diabetic foot ulcer were included. RESULTS: ANCOVA analyses showed rural patients had significantly higher WIfI composite scores (F(1,451) = 9.61, p = .002), grades of wound (F(1,439) = 11.03, p = .001), and ischemia (F(1,380) = 12.574, p = .001) compared to the urban patients. Patients that resided in at-risk economic counties had significantly higher overall WIfI composite scores (F(2,448) = 3.31, p = .037) than patients who lived in transitional economic counties, and higher foot infection grading (F(2,440) = 3.02, p = .05) compared to patients who lived in distressed economic counties. DFU patients who resided in distressed economic counties presented with higher individual grades of ischemia (F(2, 377) = 3.14, p = .04) than patients in transitional economic counties. Chi-Square analyses demonstrated patients who resided in urban counties were significantly more likely to present with grade 1 wounds (χ2(3) = 9.86, p = .02) and grade 0 ischemia (χ2(3) = 16.18, p = .001) compared to patients in rural areas. Economically distressed patients presented with significantly less grade 0 ischemia compared to patients in transitional economic counties (χ2(6) = 17.48, p = .008). CONCLUSIONS: Our findings are the first to demonstrate the impact of geographic and economic disparities on the disease burden of DFU at presentation utilizing the SVS WIfI classification system. This may indicate need for improved multidisciplinary primary care prevention strategies with vascular specialists in these communities to mitigate worsening DFU and promote early intervention.

Ambulatory Status before Diabetic Foot Ulcer Development as a Predictor of Amputation and 1-Year Outcomes: A Retrospective Analysis.

Background: Up to 25% of people with diabetes develop a diabetic foot ulcer (DFU) during their lifetime, which precedes approximately 85% of nontraumatic lower limb amputations. Diabetic limb salvage has been at the forefront of recent research, as major amputation is associated with 5-year mortality rates of 52%-80%. We sought to determine if ambulatory status before DFU diagnosis is predictive of amputations and outcomes within 1 year, as no studies have directly examined this relationship. Methods: A retrospective review of patients diagnosed with DFUs from January 2011 to December 2021 was performed. Patients aged 18 years or more with type II diabetes were included. Ambulatory status was defined as the primary form of mobility reported by the patient before development of DFU, and was categorized as independent ambulation, ambulatory with assisting device (AWAD), or nonambulatory (NA). Statistical analyses included χ2, multinomial, and multivariable logistic regressions. Results: After review, 506 patients were included. NA (OR = 5.10; P = 0.002) and AWAD status (OR = 2.77; P = 0.01) before DFU development were predictive of major (below or above-knee) amputation during hospitalization, emergency department visits within 30-days (NA: OR = 4.19; P = 0.01, AWAD: OR = 3.09; P = 0.02), and mortality within one-year (NA: OR = 4.19; P = 0.01, AWAD: OR = 3.09; P = 0.02). AWAD status was also associated with increased risk of hospital readmission (OR = 2.89; P < 0.001) within 30-days and any amputation (OR = 1.73; P = 0.01) within 1 year. Conclusions: In patients with DFUs, NA and AWAD status were predictive of major amputation during hospitalization and are associated with poorer 1-year outcomes, including mortality. Ambulatory status assessment may be used to inform DFU treatment approaches.

Dietary supplementation with Zyflamend poly-herbal extracts and fish oil inhibits intimal hyperplasia development following vascular intervention.

The polyherbal blend Zyflamend™ has been shown to have anti-inflammatory properties and attenuate inflammatory-modulated pathologies. Fish oils have also been shown to have cardioprotective properties. However, the beneficial effects of their combination have not been investigated. Intimal hyperplasia (IH), a pathological remodeling response of a vessel to injury, is heavily regulated by an immune-mediated reaction. The objective of this study was to determine if dietary supplementation with Zyflamend and/or Wholemega could affect inflammatory-dependent vascular remodeling mechanisms when provided at human equivalent doses. Based on their anti-inflammatory properties and protective benefits demonstrated in previous pre-clinical studies, we hypothesized administration of these supplements would prevent IH in an animal model of vascular injury. The diets of aged male rats were supplemented with human equivalent doses of Zyflamend (Zyf) and/or Wholemega (WMega) or placebo (Plac) for 1wk prior to balloon angioplasty (BA)-induced injury of the left carotid artery. At 28d post-injury morphometric analysis of carotid tissue revealed IH was decreased in Zyf + WMega animals compared to placebo, while Zyf or WMega independently had no significant effect. Serum cytokine screening indicated injury-induced interleukin family isoforms, interferon-γ, and macrophage inflammatory proteins were downregulated by Zyf + WMega. Immunohistochemical staining for monocyte/macrophage phenotypic markers revealed that while overall monocyte/macrophage vessel infiltration was not affected, Zyf + WMega limited the alternative differentiation of M2 macrophages and reduced the presence of myofibroblasts in the injured vessel wall. In summary, dietary supplementation with Zyf + WMega attenuated the acute inflammatory response following vascular injury and inhibited IH development in vivo.

Diabetic Foot Ulcers: The Importance of Patient Comorbidity Recognition and Total Contact Casting in Successful Wound Care.

Diabetic foot ulcers (DFUs) are a major burden on the health-care system. The purpose of this study is to investigate factors affecting the healing rate of DFU in a university wound care center. Records of DFU patients treated between July 2013 and February 2015 were reviewed. Demographics, comorbidities, wound characteristics, and treatment modalities including offloading, hyperbaric oxygen treatment, total contact casting, and bioengineered skin were investigated. All patients underwent weekly debridement regardless of treatment modality. A total of 114 patients ages 18 to 98 comprised the study population. Total contact casting was the only treatment associated with increased healing (P = 0.02). Smoking (P = 0.004) and deep vein thrombosis history (P = 0.001) significantly decreased the likelihood of wound healing. Patients with past vascular event trended toward longer healing times (P = 0.07). Total contact casting in combination with weekly wound debridement showed benefit in DFU wound healing, whereas patients with a history of deep vein thrombosis and smoking were less likely to heal.

Comparative analysis of polymers for short interfering RNA delivery in vascular smooth muscle cells.

UNLABELLED: The use of short interfering RNA (siRNA) to degrade messenger RNA in the cell cytoplasm and transiently attenuate intracellular proteins shows promise in the inhibition of vascular pathogenesis. However, a critical obstacle for therapeutic application is a safe and effective delivery system. Biodegradable polymers are promising alternative molecular carriers for genetic material. Here, we aim to perform a comparative analysis of poly(B-amino ester) (PBAE) and polyethylenimine (PEI) polymers in their efficacy for vascular smooth muscle cell transfection using siRNA against the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) housekeeping gene as our test target. METHODS: Human aortic smooth muscle cells (HASMC) were transfected in vitro with polymers conjugated to GAPDH or negative control (NC) siRNAs. Increasing siRNA:polymer ratios were tested for optimal transfection efficiency. DharmaFECT2 chemical transfection complexes were used for comparative analysis. Live/dead dual stain was used to measure cell viability, and GAPDH gene silencing was measured by quantitative polymerase chain reaction normalized to 18S. RESULTS: The highest rate of PEI-mediated silencing was achieved with a 9µL polymer:220 pmol/mL siRNA conjugate (16 ± 2% expression versus NC; n = 6). Comparable PBAE-mediated silencing could be achieved with a 1.95µL polymer:100 pmol/mL siRNA conjugate (10 ± 1% expression versus NC; n = 5). Transfection using PEIs resulted in silencing equivalent to other methods but with less efficiency and increased cell toxicity at 24h polymer exposure. Decreasing PEI exposure time to 4 h resulted in similar silencing efficacy (21 ± 9% expression versus NC, n = 6) with an improved toxicity profile. CONCLUSIONS: Polymeric bioconjugates transfected HASMCs in a manner similar to chemical complexes, with comparable cell toxicity and silencing efficiency. PEI bioconjugates demonstrated silencing equivalent to PBAE bioconjugates, although less efficient in terms of required polymer concentrations. Given the cost-to-benefit difference between the assayed polymers, and PEI's ability to transfect HASMCs within a short duration of exposure with an improved toxicity profile, this study shows that PEI bioconjugates are a potential transfection agent for vascular tissue. Future studies will expand on this method of gene therapy to validate delivery of gene-specific inhibitors aimed at attenuating smooth muscle cell proliferation, adhesion, and migration. These studies will lay the framework for our future experimental plans to expand on this method of gene therapy for in vivo transfection in animal models of vascular disease.

Predicting academic performance in surgical training.

INTRODUCTION: During surgical residency, trainees are expected to master all the 6 competencies specified by the ACGME. Surgical training programs are also evaluated, in part, by the residency review committee based on the percentage of graduates of the program who successfully complete the qualifying examination and the certification examination of the American Board of Surgery in the first attempt. Many program directors (PDs) use the American Board of Surgery In-Training Examination (ABSITE) as an indicator of future performance on the qualifying examination. Failure to meet an individual program's standard may result in remediation or a delay in promotion to the next level of training. Remediation is expensive in terms of not only dollars but also resources, faculty time, and potential program disruptions. We embarked on an exploratory study to determine if residents who might be at risk for substandard performance on the ABSITE could be identified based on the individual resident's behavior and motivational characteristics. If such were possible, then PDs would have the opportunity to be proactive in developing a curriculum tailored to an individual resident, providing a greater opportunity for success in meeting the program's standards. METHODS: Overall, 7 surgical training programs agreed to participate in this initial study and residents were recruited to voluntarily participate. Each participant completed an online assessment that characterizes an individual's behavioral style, motivators, and Acumen Index. Residents completed the assessment using a code name assigned by each individual PD or their designee. Assessments and the residents' 2013 ABSITE scores were forwarded for analysis using only the code name, thus insuring anonymity. Residents were grouped into those who took the junior examination, senior examination, and pass/fail categories. A passing score of ≥70% correct was chosen a priori. Correlations were performed using logistic regression and data were also entered into a neural network (NN) to develop a model that would explain performance based on data obtained from the TriMetrix assessments. RESULTS: A total of 117 residents' TriMetrix and ABSITE scores were available for analysis. They were divided into 2 groups of 64 senior residents and 53 junior residents. For each group, the pass/fail criteria for the ABSITE were set at 70 and greater as passing and 69 and lower as failing. Multiple logistic regression analysis was complete for pass/fail vs the TriMetrix assessments. For the senior data group, it was found that the parameter Theoretical correlates with pass rate (p < 0.043, B = -0.513, exp(B) = 0.599), which means increasing theoretical scores yields a decreasing likelihood of passing in the examination. For the junior data, the parameter Internal Role Awareness correlated with pass/fail rate (p < 0.004, B = 0.66, exp(B) = 1.935), which means that an increasing Internal Role Awareness score increases the likelihood of a passing score. The NN was able to be trained to predict ABSITE performance with surprising accuracy for both junior and senior residents. CONCLUSION: Behavioral, motivational, and acumen characteristics can be useful to identify residents "at risk" for substandard performance on the ABSITE. Armed with this information, PDs have the opportunity to intervene proactively to offer these residents a greater chance for success. The NN was capable of developing a model that explained performance on the examination for both the junior and the senior examinations. Subsequent testing is needed to determine if the NN is a good predictive tool for performance on this examination.

Androgens regulate MMPs and the cellular processes of intimal hyperplasia.

BACKGROUND: Testosterone deficiency has been associated with an increased risk of vascular disease. Matrix metalloproteinases (MMPs) have been implicated in vascular remodeling. Our group has demonstrated an association between female hormones and MMP-modulated intimal hyperplasia. In the present study, we investigated testosterone in the modulation of MMPs and the cellular processes of intimal hyperplasia. MATERIALS AND METHODS: Male vascular smooth muscle cells (VSMCs) were treated with a range of testosterone or dihydrotestosterone (DHT) concentrations (0.3-3000 nM). MMPs were assayed using quantitative polymerase chain reaction, Western blot analysis, and zymography. VSMC migration and proliferation were assayed using Boyden chamber and MTT assays. RESULTS: MT1-MMP gene expression was not affected by low DHT exposure but was downregulated at high levels (3000 nM = 85% ± 3%). TIMP-2 gene expression was downregulated at low DHT exposure (0.3 nM = 82% ± 4%, 3.0 nM = 82% ± 1%) but was not affected at high levels. MMP-2 enzymatic activity was increased at low DHT exposure (3.0 nM = 110% ± 4%) and decreased below basal levels at high doses (300 nM = 91% ± 7%, 3000 nM = 77% ± 8%). High concentrations of DHT decreased VSMC migration (3.0 nM = 72% ± 9%, 30 nM = 50% ± 6%, 300 nM = 47% ± 5%, 3000 nM = 53% ± 6%). Testosterone also decreased migration but had less effect. The highest tested concentration of DHT and testosterone decreased the basal VSMC proliferation (3000 nM = 87% ± 3% and 87% ± 4% respectively). CONCLUSIONS: The DHT levels differentially affected the expression of regulatory isoforms responsible for the activation and inhibition of MMP-2, leading to an inverse relationship among the DHT levels, MMP-2 activity, and VSMC migration. In vivo studies will be used to examine testosterone deficiency and supplementation in MMP-modulated intimal hyperplasia in animal models of vascular disease. These studies are needed as a prerequisite to determining whether testosterone replacement in testosterone-deficient men should be evaluated for attenuation of atherosclerosis.

Poly-ADP-ribose-polymerase inhibition ameliorates hind limb ischemia reperfusion injury in a murine model of type 2 diabetes.

INTRODUCTION: Diabetes is known to increase poly-ADP-ribose-polymerase (PARP) activity and posttranslational poly-ADP-ribosylation of several regulatory proteins involved in inflammation and energy metabolism. These experiments test the hypothesis that PARP inhibition will modulate hind limb ischemia reperfusion (IR) in a mouse model of type-II diabetes and ameliorate the ribosylation and the activity/transnuclear localization of the key glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). METHODS: db/db mice underwent 1.5 hours of hind limb ischemia followed by 1, 7, or 24 hours of reperfusion. The treatment group received the PARP inhibitor PJ34 (PJ34) over a 24-hour period; the untreated group received Lactated Ringer (LR) at the same time points. IR muscles were analyzed for indices of PARP activity, fiber injury, metabolic activity, inflammation, GAPDH activity/intracellular localization, and poly-ADP-ribosylation of GAPDH. RESULTS: PARP activity was significantly lower in the PJ34-treated groups than in the Lactated Ringer group at 7 and 24 hours of reperfusion. There was significantly less muscle fiber injury in the PJ34-treated group than in the Lactated Ringer-treated mice at 24 hours of reperfusion. PJ34 lowered levels of select proinflammatory molecules at 7 hours and 24 hours of IR. There were significant increases in metabolic activity only at 24 hours of IR in the PJ34 group, which temporally correlated with increase in GAPDH activity, decreased GAPDH poly-ADP-ribosylation, and nuclear translocation of GAPDH. CONCLUSIONS: PJ34 reduced PARP activity, GAPDH ribosylation, and GAPDH translocation; ameliorated muscle fiber injury; and increased metabolic activity after hind limb IR injury in a murine model of type-II diabetes. PARP inhibition might be a therapeutic strategy after IR in diabetic humans.

Effect of hormone replacement therapy in matrix metalloproteinase expression and intimal hyperplasia development after vascular injury.

BACKGROUND: Postmenopausal women taking hormone replacement therapy (HRT) require secondary intervention after vascular reconstruction more frequently than women not taking HRT, often due to increased development of intimal hyperplasia (IH). Matrix metalloproteinases (MMPs) play a role in IH by degradation and remodeling of components of the vascular basement membrane. The MMP pathway is regulated by a balance between MMPs, membrane-type MMPs (MT-MMPs), and tissue inhibitor of MMPs (TIMPs). We have recently provided evidence for unbalanced regulation of the MT1-MMP/MMP-2 pathway in vascular smooth muscle cells (VSMCs) exposed to hormones in vitro. Herein we study the role of HRT in the development of IH in a postmenopausal rodent model of vascular injury and in the modulation of this MMP regulatory pathway in vivo. METHODS: Female rats were aged to 12 months. Animals were ovariectomized (OVX) and 4 weeks later hormones or placebo was delivered via a 90-day slow-release pellet. After 6 weeks of HRT each rat underwent balloon angioplasty of the left common carotid artery. At 14 days postinjury tissue samples were collected and stained with trichrome elastin and for isoform-specific MMPs. RESULTS: After vascular injury, the intima:media (I:M) ratio was decreased in OVX rats receiving placebos as compared with non-OVX controls (P < 0.05). In OVX animals receiving HRT, estrogen with and without progesterone and progesterone alone slightly increased I:M ratio compared with placebo, although no significant difference was found in any HRT group. Injury-induced intimal expression of MMP-2 and -9 was decreased in OVX placebo animals compared with non-OVX controls (P < 0.05). MMP-2 and -9 levels were subsequently increased by each type of hormone therapy compared with placebo, with a significant increase in MMP-9 in response to estrogen with and without progesterone (P < 0.05). Conversely, TIMP-2 was decreased by estrogen compared with placebo (P < 0.05). There was no effect on intimal MT1-MMP in any group. CONCLUSIONS: In this study we detected a statistically significant decrease in IH as a result of OVX. Subsequent HRT exposure resulted in increased I:M ratios compared with OVX animals given placebo, although significance was not reached with the doses given. Long-term exogenous exposure may have a more deleterious effect compared with acute exposure and should be examined further. We also demonstrated a significant reduction in MMP-2 and -9 and TIMP-2 in response to OVX. Subsequent hormone exposure resulted in the upregulation of MMP-2 and -9 without a counterregulatory increase in TIMP, indicating that HRT modulates the MMP regulatory pathway in vivo. The data suggest that the lack of hormones after OVX protects against pathologic remodeling in our aged model of disease and that exposure to both natural and exogenous hormones could be a negative risk factor resulting in an exaggerated vascular response to injury. Future studies should focus on in vivo manipulation of unbalanced MMP regulation for prevention of IH in response to HRT and in general. Furthermore, the age-associated difference in response to the presence of natural hormones in young vs aged models should be investigated.

Contemporary outcomes of vertebral artery injury.

OBJECTIVE: Vertebral artery injury (VAI) associated with cervical trauma is being increasingly recognized with more aggressive screening. Disparate results from previous literature have led to uncertainty of the significance, natural history, and optimal therapy for VAI. METHODS: To understand the natural history and treatment outcomes from our experience, we performed a retrospective, single-center review from a level I trauma center for the previous 10 years of all VAI. Injuries were identified from search of an administrative trauma database, a resident-run working database, and all radiology dictations for the same period. All VAI were classified according to segmental involvement, Denver grading scale, and laterality. Analysis of associated injuries, demographics, neurologic outcome, mortality, length of stay, treatment plan, and follow-up imaging was also performed. RESULTS: Fifty-one patients with VAI were identified from 2001 to 2011 from a total of 36,942 trauma admissions (0.13% incidence). Associated injuries were significant with an average New Injury Severity Score of 29.6. Penetrating trauma occurred in 14%. Cervical spine fracture was present in 88% with VAI. Diagnosis was obtained with computed tomographic angiography (CTA) in 95%. Screening was prompted by injury pattern or high-risk mechanism in all cases. Injuries classified according to the Denver grading scale were grade I = 24%, grade II = 35%, grade III = 4%, grade IV = 35%, and grade V = 2%. Distribution across segments included V1 = 18%, V2 = 67%, V3 = 31%, and V4 = 6%. Only one posterior circulation stroke was attributable to VAI. Overall mortality was 8%, with each mortality being associated with significant other organ injuries. Treatment rendered for VAI was antiplatelet therapy (50%), observation (31%), warfarin (17%), and stent (2%). There were no significant differences between treatment groups on any variable with the exception of body mass index (P = .047). Follow-up was obtained for 13% (n = 6) of survivors. The CTA demonstrated injury stability in four patients and resolution in two patients. Accuracy of the administrative trauma database was 53% compared with 96% for the resident-run working database. CONCLUSIONS: Neurologic sequelae attributable to VAI were rare. Grade of VAI or vertebral artery segment did not correlate with morbidity. We did not observe any differences in short-term outcomes between systemic anticoagulation and antiplatelet therapy. Of those patients seen at follow-up, injury resolution or stability was documented by CTA. A conservative approach with either observation or antithrombotic therapy is suggested. If the natural history of VAI includes a very low stroke rate, then therapies with a lower therapeutic index, such as systemic anticoagulation, in the severely injured trauma patient are not supported. Our search strategy urges awareness of the limitations of administrative databases for retrospective vascular study.

The University of Tennessee Medical Center at Knoxville.

The University of Tennessee Medical Center at Knoxville hosts the University Health Services and the University of Tennessee Graduate School of Medicine. Founded in 1956, the center along with the Department of Surgery has grown in size and in academic stature to become an outstanding tertiary clinical, medical education, and research center.

Effect of local anesthetic on microorganisms in a murine model of surgical site infection.

BACKGROUND: Surgical site infections are common, with an incidence of 1.5% to 5% for all types of surgery. In vitro studies suggest an antimicrobial effect of local anesthetic. We hypothesized that subcutaneous infiltration of local anesthetic before surgical incision would reduce the incidence of postoperative wound infection. METHODS: In a wound infection model using 4- to 6-week-old female mice, Staphylococcus aureus and Escherichia coli were inoculated in surgical wounds infiltrated with local anesthetic or saline. On day 5, the mice were killed and tissues were evaluated for viable bacterial numbers, presence of bacteria histologically, and degree of inflammation on a scale of 0 to 3 based on number and types of inflammatory cells and presence of necrosis. RESULTS: A one-way between-subjects analysis of variance with Tukey honestly significant difference post hoc comparisons showed no statistically significant difference in the degree of inflammation in mice infiltrated with lidocaine, lidocaine mixed with bupivacaine, or saline (p = 0.994, p = 0.337, and p = 0.792, respectively). A Tukey honestly significant difference post hoc analysis demonstrated that the saline (p = 0.038) and lidocaine mixed with bupivacaine (p = 0.006) had significantly lower degrees of inflammation than did the lidocaine group. A Bonferroni post hoc test demonstrated that those in the lidocaine (p = 0.003) and lidocaine mixed with bupivacaine (p = 0.008) groups had significantly higher inflammation than those in the saline group after controlling for the condition of the inocula. CONCLUSIONS: Infiltrate, whether saline, lidocaine, or lidocaine mixed with Marcaine, did not result in significantly different bacterial presence or higher degree of inflammation when controlling for experimental condition of bacterial inocula. Thus, subcutaneous infiltration of local anesthetic before a surgical incision is made does not reduce the incidence of bacterial growth or influence the degree of inflammation which alters infection rates.

Maximal venous outflow velocity: an index for iliac vein obstruction.

Leg swelling is a common cause for vascular surgical evaluation, and iliocaval obstruction due to May-Thurner syndrome (MTS) can be difficult to diagnose. Physical examination and planar radiographic imaging give anatomic information but may miss the fundamental pathophysiology of MTS. Similarly, duplex ultrasonographic examination of the legs gives little information about central impedance of venous return above the inguinal ligament. We have modified the technique of duplex ultrasonography to evaluate the flow characteristics of the leg after tourniquet-induced venous engorgement, with the objective of revealing iliocaval obstruction characteristic of MTS. Twelve patients with signs and symptoms of MTS were compared with healthy control subjects for duplex-derived maximal venous outflow velocity (MVOV) after tourniquet-induced venous engorgement of the leg. The data for healthy control subjects were obtained from a previous study of asymptomatic volunteers using the same MVOV maneuvers. The tourniquet-induced venous engorgement mimics that caused during vigorous exercise. A right-to-left ratio of MVOV was generated for patient comparisons. Patients with clinical evidence of MTS had a mean right-to-left MVOV ratio of 2.0, asymptomatic control subjects had a mean ratio of 1.3, and MTS patients who had undergone endovascular treatment had a poststent mean ratio of 1.2 (P = 0.011). Interestingly, computed tomography and magnetic resonance imaging results, when available, were interpreted as positive in only 53% of the patients with MTS according to both our MVOV criteria and confirmatory venography. After intervention, the right-to-left MVOV ratio in the MTS patients was found to be reduced similar to asymptomatic control subjects, indicating a relief of central venous obstruction by stenting the compressive MTS anatomy. Duplex-derived MVOV measurements are helpful for detection of iliocaval venous obstruction, such as MTS. Right-to-left MVOV ratios and postengorgement spectral analysis are helpful adjuncts to duplex imaging for leg swelling. The MVOV maneuvers are well tolerated by patients and yields physiological data regarding central venous obstruction that computed tomography and magnetic resonance imaging fail to detect.

Smooth muscle cell polymeric transfection is an efficient alternative to traditional methods of experimental gene therapy.

BACKGROUND: Gene therapy shows promise in the treatment of vascular disease. However, traditional transfection methods commonly used in the laboratory are poorly translatable to in vivo conditions, primarily due to the immune response to viral vectors, the cellular toxicity of chemical transfection, and the technical impracticality of electroporation. Biodegradable polymers have shown promise as a safe, predictable, and nontoxic alternative, relying on endocytosis of synthetic polymeric carriers, which are bioconjugated to the targeted genetic material of choice. However, to date most of the feasibility studies have been exclusively performed in stem cells. Differentiated cell types would be prime targets for therapeutic gene modulation in the prevention of various disease processes. We aim to establish polymeric transfection as a method for gene therapy in cells of vascular origin. Here we compared the efficiency of polymeric transfection with chemical transfection agents routinely used in a laboratory setting in vascular smooth muscle cells. METHODS: Human aortic smooth muscle cells (HASMC) were transfected with fluorescently labeled GAPDH siRNA or negative control (NC) siRNA. Transfection methods included poly(B-amino ester) polymer (StemFECT) bioconjugates, DharmaFECT2 complexes, and Santa Cruz complexes. Conjugate endocytosis was confirmed by fluorescent microscopy, and GAPDH gene silencing was assayed by qPCR normalized to 18S. RESULTS: Santa Cruz reagent complexes were the least efficient, with the maximum achievable gene silencing using a 9 µL reagent : 70 pmol siRNA/mL complex (59% ± 6%; n = 3). Maximum GADPH gene silencing using DharmaFECT2 was achieved with a 1.5 µL reagent : 100 pmol siRNA/mL complex (19% ± 1% expression versus NC; n = 4). Equivalent silencing was achieved using a comparable StemFECT bioconjugate of 1.3 µL polymer : 100 pmol siRNA/mL (25% ± 3% expression versus NC; n = 4; P = NS versus DharmaFECT2). By increasing the StemFECT bioconjugate to 1.95 µL polymer : 100 pmol siRNA/mL, gene silencing was significantly increased (10% ± 1% expression versus NC; n = 6; P < 0.05 versus DharmaFECT2 and StemFECT 1.3:100). CONCLUSION: HASMCs were efficiently transfected using polymeric bioconjugates in a manner comparable to and exceeding other transfection agents routinely used in vitro. This proof of concept establishes polymeric transfection as a viable method for in vitro investigation of differentiated vascular cells. Future studies will expand on this method of gene therapy for ex vivo transfection of whole vessel segments and in vivo transfection in animal models of vascular disease. Our long-term goal is to deliver molecular inhibitors of genes thought to play a role in intimal hyperplasia, restenosis, and vessel graft failure.

Role of MT1-MMP in estrogen-mediated cellular processes of intimal hyperplasia.

BACKGROUND: Hormone replacement therapy increases intimal hyperplasia (IH) following vascular intervention. Matrix metalloproteinases (MMPs) play a role in IH development. We have shown estrogen up-regulates MT1-MMP expression, a transmembrane protein that activates MMP-2, and increases vascular smooth muscle cell (VSMC) collagen invasion via increased MMP-2 activity. Here we hypothesize inhibition of MT1-MMP will prevent hormonally-stimulated increased MMP-2 activation and the downstream cellular processes of IH pathogenesis. METHODS: VSMCs from a postmenopausal donor were transfected with MT1-MMP or negative control siRNAs, treated with estrogen (Est), analyzed by q-PCR, Western blot, zymography, migration, invasion, and proliferation assays. RESULTS: Est treatment of MT1-MMP silenced cells still resulted in increased MT1-MMP expression (C = 41% ± 4%; Est = 52% ± 2%; P < 0.05). Silencing of MT1-MMP decreased basal MMP-2 activity (nonsilenced = 100%; MT1-silenced = 87% ± 3%; P < 0.05) but had no effect on basal invasion or proliferation. Est treatment of MT1-MMP silenced cells still resulted in increased MMP-2 activity (C = 87% ± 3%; Est = 101% ± 4%; P < 0.05) and invasion (C = 89% ± 6%; Est = 109% ± 3%; P < 0.05) compared with MT1-MMP silenced control cells. However, silencing of MT1-MMP did inhibit Est- and serum-stimulated proliferation (C = 106% ± 18%; Est = 104% ± 16%; FBS = 121% ± 24%; P = NS). CONCLUSION: Silencing of MT1-MMP in aged VSMCs results in impaired but not complete inhibition of basal and Est-stimulated increases in MMP-2 activity. Other mechanisms appear to be playing a role in hormonally-regulated cellular processes of IH pathogenesis. Future studies will target other signaling cascades, with the goal of identifying mechanisms responsible for hormonally-modulated unbalanced MMPs. In vivo manipulation of the expression patterns of MT1-MMP will be examined for the prevention of IH in animal models of vascular disease.

The predictive value of general surgery application data for future resident performance.

OBJECTIVE: The predictive value of application data for future general surgery resident performance and attrition are poorly understood. We sought to determine what variables obtained in the application process might predict future resident success. METHODS: We performed an 18-year review (1990-2008) of all matched residents (n = 101) to a university program. Both categorical graduates (CG) and nongraduates (CNG) and nondesignated preliminaries matching (PM) and preliminaries nonmatching (PNM) were evaluated. We also screened for previous high-performance accomplishments outside of the medical field such as in the performing arts or collegiate athletics (SKILL). Outcome data include graduation or match status, American Board of Surgery In-service Training Examination (ABSITE), and faculty Accreditation Council for Graduate Medical Education (ACGME) core competency evaluations. RESULTS: Background data from the Electronic Residency Application Service (ERAS) application between the various groups was compared with univariate analysis and logistic regression. There were significant differences between the groups on the measures of USMLE step 1 (STEP1) (p = 0.001), medical school grade point average (GPA) (p = 0.023), interview data (INTERVIEW) (p < 0.001), and ABSITE (p < 0.001). The variable of INTERVIEW had an odds ratio of 188.27 (95% confidence interval, 3.757-9435.405). Overall attrition was 23.7% (n = 24) and was evenly divided between those who left for lifestyle reasons and those who were encouraged to leave. CONCLUSIONS: Within our system, INTERVIEW, USMLE STEP1, and SKILL predict successful completion of a general surgery residency. In contrast to prior reports, female sex, ethnicity, medical school grades, or Alpha Omega Alpha Honor Society (AOA) status were not significant. The variable SKILL is novel and highlights the importance of nonacademic background data. Our data indicate STEP1 is an independent predictor of resident success in general surgery and should maintain an important role in general surgery applicant screening. The ideal screening threshold is likely > 215.

Serum levels of matrix metalloproteinase-2 as a marker of intimal hyperplasia.

BACKGROUND: A primary component in the development of intimal hyperplasia (IH) in response to vascular injury is basement membrane remodeling. Matrix metalloproteinases (MMPs) play a major role in this process by degradation of basement membrane proteins, mainly collagen type IV. Vascular injury initiates an inflammatory cascade with the release of tumor necrosis factor-alpha (TNFalpha), interleukin-1beta (IL-1beta), and C-reactive protein (CRP). We hypothesize serum levels of these elements may serve as biomarkers of the development of IH. METHODS AND RESULTS: At baseline, 2, 7, 10, and 14 days post-balloon angioplasty of the carotid artery, rat tissue samples were stained with Masson trichrome elastin to examine IH. Intima:media ratios (I:M) increased significantly over time postinjury. Serum samples were collected at the time of tissue sampling, and levels of MMP-2, MMP-9, collagen type IV, TNFalpha, IL-1beta, and CRP were assayed using sandwich enzyme-linked immunosorbent assay (ELISA). MMP-2 serum levels at 7, 10, and 14 days postinjury were significantly elevated compared with baseline. Other elements were not significantly elevated. CONCLUSION: Early and persistent elevation in the serum levels of MMP-2 may be a useful biomarker of basement membrane remodeling and the presence of IH.

Rural surgery rotation during surgical residency.

General surgery in the rural hospital is threatened by declining resident interest in pursuing a career in the rural setting. We found that by initiating a rural rotation of 3 months in the senior resident years, a case mix that more approximated that of the rural surgeons was experienced. Also, by experiencing a rural rotation, more residents chose to practice in a rural setting when compared with residents before the initiation of the rotation.