Prospective monitoring of adverse events following vaccination with Modified vaccinia Ankara - Bavarian Nordic (MVA-BN) administered to a Canadian population at risk of Mpox: A Canadian Immunization Research Network study

MVA-BN is an orthopoxvirus vaccine that provides protection against both smallpox and mpox. In June 2022, Canada launched a publicly-funded vaccination campaign to offer MVA-BN to at-risk populations including men who have sex with men (MSM) and sex workers. The safety of MVA-BN has not been assessed in this context. To address this, the Canadian National Vaccine Safety Network (CANVAS) conducted prospective safety surveillance during public health vaccination campaigns in Toronto, Ontario and in Vancouver, British Columbia. Vaccinated participants received a survey 7 and 30 days after each MVA-BN dose to elicit adverse health events. Unvaccinated individuals from a concurrent vaccine safety project evaluating COVID-19 vaccine safety were used as controls. Vaccinated and unvaccinated participants that reported a medically attended visit on their 7-day survey were interviewed. Vaccinated participants and unvaccinated controls were matched 1:1 based on age group, gender, sex and provincial study site. Overall, 1,173 vaccinated participants completed a 7-day survey, of whom 75 % (n = 878) also completed a 30-day survey. Mild to moderate injection site pain was reported by 60 % of vaccinated participants. Among vaccinated participants 8.4 % were HIV positive and when compared to HIV negative vaccinated individuals, local injection sites were less frequent in those with HIV (48 % vs 61 %, p = 0.021), but health events preventing work/school or requiring medical assessment were more frequent (7.1 % vs 3.1 %, p = 0.040). Health events interfering with work/school, or requiring medical assessment were less common in the vaccinated group than controls (3.3 % vs. 7.1 %, p < 0.010). No participants were hospitalized within 7 or 30 days of vaccination. No cases of severe neurological disease, skin disease, or myocarditis were identified. Our results demonstrate that the MVA-BN vaccine appears safe when used for mpox prevention, with a low frequency of severe adverse events and no hospitalizations observed.

Stroke: Hospital Nursing Management Within the First 24 Hours

Within the United States, someone will have a stroke approximately every 40 seconds. Eighty-five percent of strokes are ischemic, with 15% classified as either intracranial or subarachnoid hemorrhage. Stroke care is complex, and nurses play a critical role in identification, assessment, management, and coordination throughout the stroke continuum of care. This article will explore the nursing care of the patient with ischemic and hemorrhagic stroke during the first 24 hours.

Improving Stroke Measure Compliance and Outcomes Through Hospital Collaboration

Globally, national stroke registries have been shown to improve the quality of patient care and outcomes. However, registry utilization and implementation vary by country. In the United States, stroke-specific performance measures must be met to achieve and maintain stroke center certification awarded by the state or nationally accredited certifying bodies. The 2 stroke registries available in the United States are the American Heart Association Get With The Guidelines-Stroke registry, which is voluntary, and the Paul Coverdell National Acute Stroke Registry, funded competitively to states by the Centers for Disease Control and Prevention. Compliance with stroke processes of care is variable, and quality improvement initiatives among organizations have been shown to have an impact on improving stroke care delivery. However, the effectiveness of interorganizational continuous quality improvement approaches, especially among competing institutions, to improving stroke care is ambiguous, and no uniform governance for successful interhospital collaboration has been identified. The purpose of this article is to review national initiatives focused on interorganizational collaboration to improve stroke care delivery with a focus on interhospital collaboration in the United States to improve stroke performance measures specific to stroke center certification. The state of Kentucky's experience and utilization of the Institute for Healthcare Improvement Breakthrough Series model with key strategies for success will be discussed to serve as a foundation and empower novice stroke leaders in learning health systems. The models may be adapted internationally for application to stroke-specific care process improvement locally, regionally, and nationally; among organizations within the same health system or competing systems; and among organizations with funding or without funding to improve stroke performance measures.

Abstract TP136: Thrombectomy Outcomes In Patients With Elevated Modified Rankin Scores

Introduction: The modified Rankin Scale (mRS) is a disability outcome measure often utilized in mechanical thrombectomy (MT) trials. An mRS of 0-2 at 90 days post intervention has been deemed a good functional outcome. Some trials required a pre-stroke mRS 0-1, while others included patients in the 0-2 range. None of the major trials enrolled patients with baseline mRS greater than 2, and there have been limited data/review of outcomes in these patients with inconclusive results. We conducted an institutional retrospective review to evaluate the proportion of patients who underwent successful MT (TICI 2b or higher) and remained at their baseline mRS. This will enable us to more appropriately evaluate if patients with higher baseline mRS should be considered for intervention.

Methods: We conducted a retrospective review of all patients who underwent successful MT at our institution through 2021. Utilizing descriptive statistics in SAS, we specifically evaluated the number of patients who remained at their baseline mRS post intervention at each level.

Results: 412 patients were included (259 patients with mRS 0, 66 with mRS 1, 36 with mRS 2, 29 with mRS 3, 16 with mRS 4, and 6 with mRS 5). Of the 412, 60 patients remained at their pre-stroke mRS at 90-days post intervention (14.29 % at mRS 0, 15.15% at 1, 16.67% at 2, 17.24% at 5, 0% at 4, and 33.33% at 5).

Conclusion: Our data suggests that patients with higher baseline mRS, specifically mRS 3, may benefit from intervention with MT to maintain their functional ability. The proportion of patients who remained at their pre-stroke mRS was higher in the subgroup with mRS 3 comparative to mRS of 0 or 1; however, there were fewer patients overall. Our institutional data also highlights that patients with baseline mRS 3 did similarly well in maintaining their premorbid functional ability as those with mRS 2 (36 vs 29 patients, 17% in each group). This ultimately suggests that patients with baseline mRS 3 should be considered for MT. There are too few patients with baseline mRS 4 and 5 in our study, and given there is already significant disability in these subgroups, it would be difficult to conclude currently that these patients should undergo intervention.

Association of Serum Pyridoxal Phosphate Levels with Established Status Epilepticus

BACKGROUND

The objective of this study was to determine the prevalence of pyridoxine deficiency, measured by pyridoxal phosphate (PLP) levels, in patients admitted to the hospital with established (benzodiazepine-resistant) status epilepticus (SE) (eSE) and to compare to three control groups: intensive care unit (ICU) patients without SE (ICU-noSE), non-ICU inpatients without SE (non-ICU), and outpatients with or without a history of epilepsy (outpatient).

METHODS

This retrospective cohort study was conducted at the University of North Carolina Hospitals and Yale New Haven Hospital. Participants included inpatients and outpatients who had serum PLP levels measured during clinical care between January 2018 and March 2021. The first PLP level obtained was categorized as normal (> 30 nmol/L), marginal (≤ 30 nmol/L), deficient (≤ 20 nmol/L), and severely deficient (≤ 5 nmol/L).

RESULTS

A total of 293 patients were included (52 eSE, 40 ICU-noSE, 44 non-ICU, and 157 outpatient). The median age was 55 (range 19-99) years. The median PLP level of the eSE group (12 nmol/L) was lower than that of the ICU-noSE (22 nmol/L, p = 0.003), non-ICU (16 nmol/L, p = 0.05), and outpatient groups (36 nmol/L, p < 0.001). Patients with eSE had a significantly higher prevalence of marginal and deficient PLP levels (90 and 80%, respectively) than patients in each of the other three groups (ICU-noSE: 70, 50%; non-ICU: 63, 54%; outpatient: 38, 21%). This significantly higher prevalence persisted after correcting for critical illness severity and timing of PLP level collection.

CONCLUSIONS

Our study confirms previous findings indicating a high prevalence of pyridoxine deficiency (as measured by serum PLP levels) in patients with eSE, including when using a more restricted definition of pyridoxine deficiency. Prevalence is higher in patients with eSE than in patients in all three control groups (ICU-noSE, non-ICU, and outpatient). Considering the role of pyridoxine, thus PLP, in the synthesis of γ-aminobutyric acid and its easy and safe administration, prospective studies on pyridoxine supplementation in patients with eSE are needed.

Comparison of Outcomes of Ischemic Stroke Initially Imaged With Cranial Computed Tomography Alone vs Computed Tomography Plus Magnetic Resonance Imaging

IMPORTANCE

Patients with acute ischemic stroke often undergo magnetic resonance imaging (MRI) in addition to computed tomography (CT), but its association with clinical outcomes is uncertain.

OBJECTIVE

To assess whether clinical outcomes of patients with acute ischemic stroke with initial CT alone were noninferior to those with additional MRI.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective observational propensity score-matched cohort study of clinical outcomes at discharge and 1 year for patients hospitalized with acute ischemic stroke was conducted at an academic medical center between January 2015 and December 2017. Data collection from an electronic medical record system performed from May 2020 through January 2022 was not completely blinded. Noninferiority margins were based on the designs of previous randomized clinical trials of ischemic stroke treatments. Statistical analysis was performed in January 2022. Participants were adults hospitalized with acute ischemic stroke with admission diagnosis based on CT. Exclusion criteria were primarily missing data. From 508 eligible patients, all 123 cases with additional MRI were propensity-score matched to 123 controls without.

EXPOSURE

MRI after initial diagnosis.

MAIN OUTCOMES AND MEASURES

Death or dependence at hospital discharge (modified Rankin Scale score of 3-6) and stroke or death occurring in survivors within 1 year after discharge.

RESULTS

Among 246 participants, the median age was 68 years (IQR, 58-78.8 years) and 131 (53.0%) were men. Death or dependence at discharge occurred more often in patients with additional MRI (59 of 123 [48.0%]) than in those with CT alone (52 of 123 [42.3%]; absolute difference, 5.7%; 95% CI, -6.7% to 18.1%), meeting the -7.50% criterion for noninferiority. Stroke or death within 1 year after discharge determined for 225 of 235 (96%) survivors occurred more often in patients with additional MRI (22 of 113 [19.5%]) than in those with CT alone (14 of 112 [12.5%]; relative risk, 1.14; 95% CI, 0.86-1.50), meeting the 0.725 relative risk criterion for noninferiority.

CONCLUSIONS AND RELEVANCE

This propensity score-matched cohort study of patients hospitalized with acute ischemic stroke found that a diagnostic imaging strategy of initial CT alone was noninferior to initial CT plus additional MRI with regard to clinical outcomes at discharge and at 1 year. Further research is needed to determine which patients hospitalized with acute ischemic stroke benefit from MRI.

Care of the Patient With Acute Ischemic Stroke (Prehospital and Acute Phase of Care): Update to the 2009 Comprehensive Nursing Care Scientific Statement: A Scientific Statement From the American Heart Association

The year 2020 was the year of the nurse, celebrating nurse scholarship, innovation, and leadership by promoting scientific nursing research, improving nursing practice, advancing nursing education, and providing leadership to influence health policy. As architects of stroke care, neuroscience nurses play a vital role in collaborating and coordinating care between multiple health professionals. Nurses improve accessibility and equity through telestroke, emergency medical services, and mobile stroke units and are integral to implementing education strategies by advocating and ensuring that patients and caregivers receive stroke education while safely transitioning through the health care system and to home. Stroke care is increasingly complex in the new reperfusion era, requiring nurses to participate in continuing education while attaining levels of competency in both the acute and recovery care process. Advanced practice nurses are taking the lead in many organizations, serving as prehospital providers on mobile stroke units, participating as members of the stroke response team, and directing stroke care protocols in the emergency department. This scientific statement is an update to the 2009 "Comprehensive Overview of Nursing and Interdisciplinary Care of the Acute Ischemic Stroke Patient." The aim is to provide a comprehensive review of the scientific evidence on nursing care in the prehospital and hyperacute emergency hospital setting, arming nurses with the necessary tools to provide evidenced-based high-quality care.

Abstract TP282: S 3 TOP for Stroke: Improving In-Hospital Stroke Alert Activation Criteria

Background and purpose: The study aimed to assess the efficiency (percent treated) of existing in-hospital stroke alert activation criteria and to improve these criteria.

Methods: 209 patient records from in-hospital stroke alerts at an academic medical center between January 2015 and December 2016 were reviewed retrospectively. Patients were sorted into five categories by final diagnosis: cerebral ischemia, cerebral hemorrhage, seizure, delirium or toxic/metabolic encephalopathy, and other. Acute treatment result of any in-hospital stroke was recorded. The study team determined adherence to the institution’s existing in-hospital stroke alert activation criteria. To improve efficiency a new set of in-hospital stroke alert activation criteria called “S3TOP for Stroke” was then developed. The checklist for “S3TOP for Stroke” guides hospital staff to assess the following items: symptoms, sedation, sugar, time, oxygenation and pulse. The checklist was then retrospectively applied to the 209 records.

Results: Of 209 patients who received in-hospital stroke alerts according to existing activation criteria: 192 (91.9%) met existing criteria, and 14 (6.7%) received acute stroke treatment. Applying the “S3TOP for Stroke” checklist to the study group excluded 56 of these and included all 14 (14/153 =9.2%) who received acute stroke treatment.

Conclusions: This study found good adherence with poor efficiency for existing institutional stroke alert activation criteria. Retrospectively, the “S3TOP for Stroke” checklist improved efficiency. Prospective testing of this algorithm is underway.

Novice lifters exhibit a more kyphotic lifting posture than experienced lifters in straight-leg lifting

As torso flexion and repetitive lifting are known risk factors for low back pain and injury, it is important to investigate lifting techniques that might reduce injury during repetitive lifting. By normalizing lumbar posture to a subject's range of motion (ROM), as a function of torso flexion, this research examined when subjects approached their range of motion limits during dynamic lifting tasks. For this study, it was hypothesized that experienced lifters would maintain a more neutral lumbar angle relative to their range of motion, while novice lifters would approach the limits of their lumbar ROM during the extension phase of a straight-leg lift. The results show a statistically significant difference in lifting patterns for these two groups supporting this hypothesis. The novice group maintained a much more kyphotic lumbar angle for both the flexion (74% of the lumbar angle ROM) and extension phases (86% of the lumbar angle ROM) of the lifting cycle, while the experienced group retained a more neutral curvature throughout the entire lifting cycle (37% of lumbar angle ROM in flexion and 48% of lumbar angle ROM in extension). By approaching the limits of their range of motion, the novice lifters could be at greater risk of injury by placing greater loads on the supporting soft tissues of the spine. Future research should examine whether training subjects to assume more neutral postures during lifting could indeed lower injury risks.

Stromal fibroblast-bone marrow-derived cell interactions: implications for myofibroblast development in the cornea

The purpose of this study was to test the hypothesis that mouse corneal stromal fibroblast and bone marrow-derived cell interactions augment corneal myofibroblast generation and, if so, to study whether such interactions are mediated by paracrine or juxtacrine mechanisms. Mouse bone marrow-derived cells and mouse corneal stromal fibroblasts were obtained from both mice with green fluorescent protein (GFP) expressed in all cells and normal GFP- BL6 control mice. To study the interactions of the different cell types, GFP+ cells of one type were co-cultured with GFP- cells of the other type in Primaria plates (to monitor juxtacrine signaling) or Transwell System plates (to monitor paracrine effects mediated by soluble mediators). Both cell types were cultured at a cell density of 1 × 10(5) cells per ml. The percentage of alpha smooth muscle actin+ myofibroblasts was significantly higher (ANOVA, p<0.001) when bone marrow-derived cells and mouse corneal stromal fibroblasts were co-cultured compared to when bone marrow-derived cells and mouse corneal stromal fibroblasts were cultured alone (control). The in vitro studies using GFP+ corneal fibroblasts or GFP+ bone marrow-derived cells demonstrated conclusively that both cells types could transform into myofibroblasts. However, the percentage of alpha smooth muscle actinassds+ myofibroblasts generated from either cell type precursor was higher when both cells were co-cultured together (juxtacrine) as compared to when bone marrow-derived cells and mouse corneal stromal fibroblasts were co-culture in different compartments of Transwell System (paracrine). Thus, more alpha smooth muscle actin+ GFP+ myofibroblasts were generated from GFP+ corneal stromal fibroblasts when GFP- bone marrow-derived cells were present and more alpha smooth muscle actin+ GFP+ myofibroblasts were generated from GFP+ bone marrow-derived cells when GFP- corneal stromal fibroblasts were present. Polyclonal anti-human latency associated peptide (LAP) (transforming growth factor-β1) neutralizing antibody (a-LAP) and/or transforming growth factor-β type I receptor kinase inhibitor (LY-364947) inhibited the generation of alpha smooth muscle actin+ myofibroblasts from either precursor cell in Transwell System co-culture experiments. These data suggest that TGFβ is a paracrine modulator that regulates the generation of myofibroblasts from either corneal fibroblasts or bone marrow-derived cell precursors.

Abstract 3074: Acute Stroke Nurse Response Pilot Program

Background: Less than 10% of ischemic stroke patients receive tissue plasminogen activator. Low treatment rates have been associated with delay in hospital presentation and reluctance to treat. Studies have found that a combination of community and professional education increase thrombolytic therapy from 2.2% to 11.3% with the data suggesting that professional education made the most impact. An Acute Stroke Nurse Response educational program was piloted as a means of providing specialized treatment education for nurses in North Carolina.

Project goals: A. Increase the number of nurses across the state experienced to provide acute stroke assessment and treatment. B. Determine the best educational approach: on-line vs. class room vs. both. C. Develop a mock code stroke training module. D. Provide guidance in developing individualized models of stroke care protocols.

Measurable objectives: A. Gauge interest in the program. B. Assess pre and post-test knowledge measuring effectiveness of modules. C. Assess nurse preference for teaching method. D. Evaluate the methodology of the mock code stroke module.

Methods: The educational program covered stroke topics through on-line modules and a one day lecture series to meet the needs of the working nurse. The program consisted of 10 specialized stroke training modules: Module 1: Introduction to Stroke Module 2: Emergency Management Module 3: Acute Stroke Treatment Module 4: Management of ICH Module 5: Stroke Prevention Module 6: Nursing Care of the Stroke Patient Lecture 7: Neurological Assessment Lecture 8: Stroke Imaging Lecture 9: Quality Improvement/Joint Commission Primary Certification Lecture 10: Mock Stroke Code 6 weeks were allowed to complete the on-line modules prior to the day lecture series. Pre and post-test exams were administered to assess baseline knowledge and knowledge gained.

Results: 42 nurses showed interest in the program. 12 nurses completed the pilot program. 10 were from NC, originating throughout the state and 2 from SC. Two participants were NP’s, 2 ED nurses, 3 staff nurses and 5 stroke coordinators. Participants had a mean pre-test score of 53.2, which increased significantly (p<0.001) to a mean post-test score of 77.8 (absolute mean improvement of 24.6%). The improvement in the scores ranged from 11.1 to 44.5% with one participant experiencing a decrease in test scores by 5.6%. Program feedback was positive, with strengths identified as “convenient and informative”. All participants requested the program continue as originally developed with on-line modules and the one day lecture series.

Conclusions: There was a significant educational benefit from this program, as demonstrated by participant responses to the pilot program.

Effect of TGFβ and PDGF-B blockade on corneal myofibroblast development in mice

The purpose of this study was to investigate the role of transforming growth factor beta (TGFβ) and/or platelet-derived growth factor-B (PDGF-B) blockade on the differentiation of vimentin and alpha-smooth muscle actin (αSMA)-expressing myofibroblasts associated with haze in mice. Mouse corneas had haze-generating irregular PTK (phototherapeutic keratectomy) and topical treatment with the vectors. Six study groups of PTK treated corneas, with four corneas per group in each experiment, were Group 1) treated with TGFβ-KDEL vector interfering with TGFβ signaling through anomalous sorting of cytokine bound to the expressed altered receptor; Group 2) treated with PDGF-B-KDEL vector interfering with PDGF signaling through anomalous sorting of cytokine bound to the expressed altered receptor; Group 3) treated with both TGFβ-KDEL vector and PDGF-B-KDEL vector to interfere with signaling of both cytokines; Group 4) empty pGFPC1 vector; Group 5) empty pCMV vector; and Group 6) no vector treatment control. At one month after surgery, the corneas were analyzed by immunocytochemistry (IHC) for central stromal cells expressing myofibroblast markers vimentin and αSMA. The stroma of corneas treated with the TGFβ-KDEL vector alone (p < 0.05) or both the TGFβ-KDEL and PDGF-B-KDEL vectors (P < 0.05) had significantly lower density of vimentin-positive cells compared to the corresponding control group. The central stroma of corneas treated with the TGFβ-KDEL vector (p < 0.05) or the PDGF-B-KDEL vector (p < 0.05) had lower density of αSMA-positive cells compared to the corresponding control group. The density of αSMA-positive stromal cells was also significantly lower (p < 0.05) when both the TGFβ-KDEL and PDGF-B-KDEL and vectors were applied together compared to the corresponding control groups. This study provides in situ evidence that TGFβ and PDGF-B have important roles in modulating myofibroblast generation in the mouse cornea after haze-associated injury.

Monocyte development inhibitor PRM-151 decreases corneal myofibroblast generation in rabbits

This study investigated whether PRM-151 (Promedior, Inc., Malvern, PA), a recombinant form of human pentraxin-2 (PTX-2, also referred to as serum amyloid P, hSAP), that inhibits differentiation of circulating monocytes into fibrocytes and profibrotic macrophages, could modulate generation of myofibroblasts after opacity-producing corneal injury in rabbits, and, therefore, have potential to reduce or prevent haze after PRK. Nine diopter PRK for myopia was performed with the VISX S4 IR laser. Four groups of 6 animals were treated in masked fashion: Group 1: 30 μl of topical PRM-151 (20 mg/ml) 6 times a day for 5 days; Group 2: 30 μl topical vehicle 6 times a day for 5 days; Group 3: 200 μl sub-conjunctival PRM-151 (total injection of 4 mg) immediately after surgery and every other day until day 8; Group 4: 200 μl sub-conjunctival injections of vehicle according to the same schedule as group 3. At one month after PRK, the animals were euthanized and immunohistochemistry was performed for the myofibroblast marker α-smooth muscle actin (SMA). The density of SMA+ cells/400× field in the central stroma was determined in each cornea. Myofibroblast density at one month after surgery was significantly lower (p = 0.006) after sub-conjunctival PRM-151 treatment (5.8 ± 2.8 cells/400× stromal field) compared to sub-conjunctival vehicle treatment (15.3 ± 2.9 cells/400× stromal field). There was no significant (p = 0.27) decrease in stromal myofibroblasts triggered by topical PRM-151 treatment (11.8 ± 6.6 cells/400× stromal field) compared to the topical vehicle treatment (14.2.8 ± 6.2 cells/400× stromal field). PRM-151 inhibits myofibroblast generation when administered by sub-conjunctival injection, but not when administered topically, after opacity-producing corneal injury. This study provides additional confirmation that bone marrow-derived cells contribute to corneal myofibroblast generation.

Anti-inflammatory approaches that target the chemokine network

Chemokine-ligand/receptor axes play pivotal roles in a myriad of inflammatory, allergic and autoimmune diseases, as well as in the promotion of tumor growth and metastasis. Upon insult, tissue resident cells (and cancer cells in general) release a defined set of inflammatory chemokines that are responsible for the recruitment of activated pathological leukocytes. Recruited leukocytes synthesize and release a host of inflammatory mediators such as chemokines, cytokines, reactive oxygen and nitrogen species, and proteinases. These agents are responsible for the maintenance and amplification of inflammatory responses, and are directly responsible for secondary tissue damage, promotion of autoimmunity, fibrosis and tissue remodelling. Many cancers are associated with the expression of chemokine ligands that co-opt leukocytes such as tumor associated macrophages which in turn provide mediators including growth factors, chemokines and proteinases that promote angiogenesis, tumor growth, and cancer metastasis. Here, we discuss the relevant patents, development and the mechanism of action of a range of therapeutic and potential therapeutic agents that specifically target the chemokine ligand and receptor network. The main approaches that will be highlighted here are antagonism, cell depletion and the relatively unexplored fields of anti-sense, gene and stem cell therapies.

Lumbar position sense with extreme lumbar angle

Tasks involving flexed torso postures have a high incidence of low back injuries. Changes in the ability to sense and adequately control low back motion may play a role in these injuries. Previous studies examining position sense errors of the lumbar spine with torso flexion found significant increases in error with flexion. However, there has been little research on the effect of lumbar angle. In this study, the aim of the study was to examine how position sense errors would change with torso flexion as a function of the target lumbar angle. Fifteen healthy volunteers were asked to assume three different lumbar angles (maximum, minimum and mid-range) at three different torso flexion angles. A reposition sense protocol was used to determine a subject's ability to reproduce the target lumbar angles. Reposition sense error was found to increase 69% with increased torso flexion for mid-range target curvatures. With increasing torso flexion, the increase in reposition sense errors suggests a reduction in sensation and control in the lumbar spine that may increase risk of injury. However, the reposition error was smaller at high torso flexion angles in the extreme target curvatures. Higher sensory feedback at extreme lumbar angles would be important in preventing over-extension or over-flexion. These results suggest that proprioceptive elements in structures engaged at limits (such as the ligaments and facet joints), may provide a role in sensing position at extreme lumbar angles. Sensory elements in the muscles crossing the joint may also provide increased feedback at the edges of the range of motion.

Functional patency of autogenous AV fistulas for hemodialysis

BACKGROUND

Although AV fistulas are the preferred access for hemodialysis and have low complication rates, failure to function remains high and time to first dialysis may be several months.

METHODS

Data from a Computerized Patient Record System of patients undergoing AV fistula from October 2000 to March 2006 were reviewed for type of fistula, interval from AV fistula construction to first hemodialysis, patency period, and complication rate.

RESULTS

129 patients were identified who underwent 155 autogenous AV fistula constructions. The average age was 62.1 (range 40-84) years old. 114 radiocephalic and 41 brachiocephalic fistulas were performed. 57 (50%) radiocephalic fistulas allowed successful hemodialysis after an average length of 13+/-5 weeks with a primary patency of 13+/-4 months. 24 (42%) fistulas subsequently thrombosed, 7 (12%) developed fistula stenosis, and 2 (4%) developed steal syndrome. 28 (68%) brachiocephalic fistulas reached successful hemodialysis after 6+/-2 weeks with a primary patency of 16+/-7 months. Eleven (42%) of the brachiocephalic fistulas that reached hemodialysis remained patent while four (15%) thrombosed. Two (8%) brachiocephalic fistulas thrombosed before reaching hemodialysis. There were two incidences (5%) of steal syndrome in the brachiocephalic group with one case being severe leading to tissue loss in the hand.

CONCLUSION

Brachiocephalic fistulas were superior to radiocephalic in both time to maturity, primary patency, and functional primary patency. Brachiocephalic fistulas had a higher maturation rate and were less likely to fail once hemodialysis began. Vascular surgeons should develop better patient selection to predict which fistulas will function successfully rather than risk complications of prolonged central catheters.

Recombinant interleukin-2 significantly augments activity of rituximab in human tumor xenograft models of B-cell non-Hodgkin lymphoma

Recombinant interleukin-2 (rIL-2) is a pleiotropic cytokine that activates select immune effector cell responses associated with antitumor activity, including antibody-dependent cellular cytotoxicity (ADCC). Rituximab is an anti-CD20 monoclonal antibody that activates ADCC in non-Hodgkin lymphoma (NHL). The ability of rIL-2 to augment rituximab-dependent tumor responses was investigated. The efficacy of rIL-2 in combination with rituximab was evaluated in 2 NHL tumor xenograft models: the CD20hi, rituximab-sensitive, low-grade Daudi model and the CD20lo, aggressive, rituximab-resistant Namalwa model. Combination of rIL-2 plus rituximab was synergistic in a rituximab-sensitive Daudi tumor model, as evidenced by significant tumor regressions and increased time to tumor progression, compared with rIL-2 and rituximab single agents. In contrast, rituximab-resistant Namalwa tumors were responsive to single-agent rIL-2 and showed an increased response when combined with rituximab. Using in vitro killing assays, rIL-2 was shown to enhance activity of rituximab by activating ADCC and lymphokine-activated killer activity. Additionally, the activity of rIL-2 plus rituximab F(ab')2 was similar to that of rIL-2 alone, indicating a critical role for immunoglobulin G1 Fc-FcgammaR-effector responses in mediating ADCC. Antiproliferative and apoptotic tumor responses, along with an influx of immune effector cells, were observed by immunohistochemistry. Collectively, the data suggest that rIL-2 mediates potent tumoricidal activity against NHL tumors, in part, through activation and trafficking of monocytes and natural killer cells to tumors. These data support the mechanistic and therapeutic rationale for combination of rIL-2 with rituximab in NHL clinical trials and for single-agent rIL-2 in rituximab-resistant NHL patients.

Laparoscopic esophagectomy

Minimally invasive esophagectomy is emerging as an alternative option to open esophagectomy for benign and malignant esophageal diseases. This article provides a detailed review of the history of minimally invasive esophagectomy and an update on the currently accepted techniques for minimally invasive esophagectomy and its outcomes.

Clinical trial results with linezolid, an oxazolidinone, in the treatment of soft tissue and postoperative gram-positive infections

BACKGROUND

Infectious complications encountered after major surgery include operative site infections and nosocomial pneumonia. Recent infection surveillance programs have identified the increasing pathogenic role of gram-positive bacteria in these infections and the high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the United States and abroad. Surgical site infections and nosocomial pneumonia, often serious infections, are associated with adverse clinical outcomes including bacteremia and its resultant complications, as well as the socioeconomic consequences of excess hospitalization and discharge to nursing care.

METHODS

The essential triad for management of postoperative soft tissue infection consists of thorough appraisal of the infection site for reintervention, culture of drainage or infected tissue, and prompt initiation of empiric antimicrobial therapy designed to cover the most probable causative pathogens. Broad-spectrum antimicrobial regimens are often necessary for empiric therapy of skin and soft tissue infections or nosocomial pneumonia; however, regimens should be tailored to the most effective and clinically appropriate agent based on results of susceptibility testing.

RESULTS

Results of the clinical trial experience with the first United States Food and Drug Administration (FDA)-approved antimicrobial in the new class of oxazolidinones, linezolid, are reviewed.

CONCLUSION

In randomized, controlled trials, linezolid 600 mg twice daily (intravenously or orally) provided effective antimicrobial therapy for gram-positive soft tissue infections, including MRSA, and nosocomial pneumonia in which S. aureus was a causative pathogen.

Active stiffness of the ankle in response to inertial and elastic loads

Effective stiffness of the musculoskeletal system was examined as a function of the characteristics of an external load. Thirteen healthy subjects provided active contraction of the ankle plantarflexion musculature in a neutral ankle posture to support an external load. Musculoskeletal stiffness was computed from kinetic data recorded in response to dorsiflexion/plantarflexion perturbations. Ankle dynamics were recorded while supporting external loads of 19 and 38 kg with and without antagonistic co-contraction. External loads were applied using pure gravitational mass. In separate trials external loads were applied from stretch of steel springs in parallel with the plantarflexion musculature that also provided added parallel stiffness to the system. Adding external stiffness of 4.9 and 8.1 kN/m surprisingly failed to significantly change the stiffness of the ankle-plus-spring system. This suggests contributions from intrinsic muscle stiffness and reflex stiffness declined in response to added external stiffness. This could not be explained by load magnitudes, ankle postures, or co-activation as these were similar between the inertial and elastic loading conditions. However, non-linear parametric analyses suggest mean intrinsic stiffness of 35.5 kN/m and reflex gain of 11.6 kN/m with a constant reflex delay of 70 ms accurately described the empirical results. The phase response between the mechanical dynamics of the musculoskeletal system and delayed neuromotor feedback combine to provide robust control of system behavior.

Phase I studies of interleukin (IL)-2 and rituximab in B-cell non-hodgkin's lymphoma: IL-2 mediated natural killer cell expansion correlations with clinical response

PURPOSE

Expansion and activation of natural killer (NK) cells with interleukin-2 (IL-2) may enhance antibody-dependent cellular cytotoxicity (ADCC), an important mechanism of rituximab activity. Two parallel Phase I studies evaluated combination therapy with rituximab and IL-2 in relapsed or refractory B-cell non-Hodgkin's lymphoma (NHL).

EXPERIMENTAL DESIGN

Thirty-four patients with advanced NHL received rituximab (375 mg/m(2) i.v. weekly, weeks 1-4) and escalating doses of s.c. IL-2 [2-7.5 MIU daily (n = 19) or 4.5-14 million international units three times weekly (n = 15), weeks 2-5]. Safety, tolerability, clinical responses, NK cell counts, and ADCC activity were evaluated.

RESULTS

Maximally tolerated doses (MTD) of IL-2 were 6 MIU daily and 14 million international units thrice weekly. The most common adverse events were fever, chills, and injection site reactions. Dose-limiting toxicities were fatigue and reversible liver enzyme test elevations. Of the 9 patients enrolled at the daily schedule MTD, 5 showed clinical response. On the thrice-weekly schedule at the MTD, 4 of 5 patients responded. Responders showed median time to progression of 14.9 and 16.1 months, respectively, for the two studies. For the same total weekly dose, thrice-weekly IL-2 administration induced greater increases in NK cell counts than daily dosing, and NK cells correlated with clinical response on the thrice-weekly regimen. ADCC activity was increased and maintained after IL-2 therapy in responding and stable disease patients.

CONCLUSIONS

Addition of IL-2 to rituximab therapy is safe and, using thrice-weekly IL-2 dosing, results in NK cell expansion that correlates with response. This combination treatment regimen merits additional evaluation in a randomized clinical trial.

The role of beta-lactam antimicrobials as single agents in treatment of intra-abdominal infection

Broad-spectrum beta-lactam antibiotics have several advantages in the treatment of intra-abdominal infections. These agents are effective against gram-negative rods and anaerobes, reach therapeutic levels rapidly after parenteral administration, and, in the absence of penicillin allergy, generally exhibit low toxicity. The second-generation cephalosporins (e.g., cefoxitin, cefotetan) are used widely in surgical prophylaxis, trauma, and treatment of mild-to-moderate community-acquired infections, but limitations in their spectra and microbial resistance restrict their utility in more serious infections. Extended-spectrum penicillin/beta-lactamase-inhibitor combinations are effective in the treatment of intra-abdominal infections and include enterococci in their spectrum. Gram-negative aerobe resistance has developed to ampicillin/sulbactam. Piperacillin/tazobactam, a ureidopenicillin with increased gram-negative coverage and enhanced antipseudomonal activity, has proved to be effective in clinical trial therapy for intra-abdominal infections. The very broad spectrum carbapenems--imipenem/cilastatin and meropenem--are effective for serious infections or resistant organisms and are often used in the intensive care unit or for nosocomial intra-abdominal infection. These classes of beta-lactams comprise a range of antimicrobials that can be targeted effectively as single agents to both prevention and treatment of intra-abdominal infection.

New alternatives in management of the infected vascular prosthesis

BACKGROUND

Infection of vascular prosthetics implanted for arterial occlusive disease occurs in approximately 1-5% of patients, including early and late clinical presentation. The incidence of infection depends on the anatomical site, with the highest rate occurring in vascular access grafts placed for hemodialysis and in inguinal and lower extremity incisions in patients undergoing bypass procedures for femoropopliteal tibial occlusion. Treatment of prosthetic graft infection has traditionally included antimicrobials, excision of the infected prosthesis, and extraanatomical bypass. With the recognition that prosthetic infection secondary to Staphylococcus epidermidis can be managed with less extensive procedures, clinical data have been reported on in situ replacement with antibiotic-bonded prostheses. Patients who have S. aureus isolated, including methicillin-resistant S. aureus, or gram-negative pathogens, still require conventional graft excision and extraanatomical bypass.

METHODS

Selective review of the English-language literature.

RESULTS

Recent clinical series show that management by graft excision of infected infrarenal aortic prosthetics and axillofemoral bypass results in 2- and 5-year survival rates of 67% and 47%, and limb salvage rates in survivors of 93% and 82% at 2 and 5 years. In situ replacement with a rifampicin-bonded prosthesis has been accomplished successfully in smaller numbers of patients and shows promising early results. Other methods under study include cryopreserved arterial and femoral vein allografts and autogenous femoral vein grafts, but data are limited when used as replacement for infected prosthetics.

CONCLUSION

Advances in the management of infected vascular prostheses over the last decade have led to improved mortality and decreased amputation rates with conventional excision and extraanatomical bypass. Newer methods including in situ graft replacement with antibiotic-impregnated prosthetics appear suitable for low-virulence S. epidermidis infection. Early results are promising for cryopreserved allografts and autogenous femoral vein in situ grafts; however, more clinical experience and longer follow-up will be needed to confirm their durability in a contaminated field.

Eradication of multi-drug resistant Acinetobacter from an intensive care unit

BACKGROUND

Acinetobacter baumannii is a gram-negative coccobacillus that causes outbreaks of nosocomial infections in ICUs. Due to resistance to multiple antibiotics, management of clusters of A. baumannii is useful as a model in eradication of multi-drug resistant infections. We outline the evolution of an A. baumannii outbreak, focusing on methods of transmission and multidisciplinary measures aimed at eliminating it from the ICU.

METHODS

Patients in an urban, tertiary care medical center from November 1996 to December 1997 having positive cultures for multi-drug resistant A. baumannii are included in this study. A. baumannii was isolated on blood agar and MacConkey cultures and identified by Vitek panel. Disk diffusion including amikacin, imipenem, polymyxin B, and sulbactam were used to determine resistance.

RESULTS

An outbreak of 52 patients (27 infected, 25 colonized) with 68 positive sites began with the transfer of a colonized >50% total body surface area burn patient from an outside hospital. Within 3 days, the index patient was in the burn ICU, coronary care unit, and medical ICU. Soon, clusters of patients with A. baumannii infections sensitive only to polymyxin B were seen in those units and, ultimately, the surgical ICU. On typing, 2 strains were found, PFGE B and C. Given the level of antibiotic resistance, patients with colonization or infection were cohorted and placed on contact isolation. Strict antiseptic measures, such as hand-washing, barrier isolation, equipment and room cleaning, sterilization of ventilator equipment, and dedication of medical equipment to each patient were instituted. Still, positive environmental cultures were found in ventilator water traps, sinks, and bedrails. Sporadic cases continued for a total of 13 months, with 10 deaths resulting from the infections.

CONCLUSION

A. baumannii is a mildly virulent organism that becomes resistant to antimicrobials. Because of multiple antibiotic resistance, strict contact isolation cohorting and antiseptic technique are the primary modes of containment. This outbreak serves as a model of eradication of multi-drug resistant organisms from ICUs. These measures will become of greater importance as nosocomial organisms develop increasing resistance to antimicrobials.

Synergistic anti-tumor responses after administration of agonistic antibodies to CD40 and IL-2: coordination of dendritic and CD8+ cell responses

In cancer, the coordinate engagement of professional APC and Ag-specific cell-mediated effector cells may be vital for the induction of effective antitumor responses. We speculated that the enhanced differentiation and function of dendritic cells through CD40 engagement combined with IL-2 administration to stimulate T cell expansion would act coordinately to enhance the adaptive immune response against cancer. In mice bearing orthotopic metastatic renal cell carcinoma, only the combination of an agonist Ab to CD40 and IL-2, but neither agent administered alone, induced complete regression of metastatic tumor and specific immunity to subsequent rechallenge in the majority of treated mice. The combination of anti-CD40 and IL-2 resulted in significant increases in dendritic cell and CD8(+) T cell number in advanced tumor-bearing mice compared with either agent administered singly. The antitumor effects of anti-CD40 and IL-2 were found to be dependent on CD8(+) T cells, IFN-gamma, IL-12 p40, and Fas ligand. CD40 stimulation and IL-2 may therefore be of use to promote antitumor responses in advanced metastatic cancer.

Gender differences in active musculoskeletal stiffness. Part II. Quantification of leg stiffness during functional hopping tasks

Leg stiffness was compared between age-matched males and females during hopping at preferred and controlled frequencies. Stiffness was defined as the linear regression slope between the vertical center of mass (COM) displacement and ground-reaction forces recorded from a force plate during the stance phase of the hopping task. Results demonstrate that subjects modulated the vertical displacement of the COM during ground contact in relation to the square of hopping frequency. This supports the accuracy of the spring-mass oscillator as a representative model of hopping. It also maintained peak vertical ground-reaction load at approximately three times body weight. Leg stiffness values in males (33.9+/-8.7 kN/m) were significantly (p<0.01) greater than in females (26.3+/-6.5 kN/m) at each of three hopping frequencies, 3.0, 2.5 Hz, and a preferred hopping rate. In the spring-mass oscillator model leg stiffness and body mass are related to the frequency of motion. Thus male subjects necessarily recruited greater leg stiffness to drive their heavier body mass at the same frequency as the lighter female subjects during the controlled frequency trials. However, in the preferred hopping condition the stiffness was not constrained by the task because frequency was self-selected. Nonetheless, both male and female subjects hopped at statistically similar preferred frequencies (2.34+/-0.22 Hz), therefore, the females continued to demonstrate less leg stiffness. Recognizing the active muscle stiffness contributes to biomechanical stability as well as leg stiffness, these results may provide insight into the gender bias in risk of musculoskeletal knee injury.

Treatment of warfarin-associated coagulopathy: a physician survey

STUDY OBJECTIVES

(1) To determine physician preferences in the management of warfarin-induced excessive anticoagulation (AC); and (2) to assess compliance with the American College of Chest Physicians (ACCP) guidelines for the reversal of excessive AC.

DESIGN

Cross-sectional physician survey.

PARTICIPANTS

Members of the Canadian Society of Internal Medicine practicing in Ontario, Canada.

MEASUREMENTS AND RESULTS

Physicians were asked to provide management preferences in six clinical scenarios describing warfarin-induced excessive AC. The scenarios represent various combinations of international normalized ratio (INR) value, treatment setting, and presence and severity of bleeding. In scenarios with INRs < 5.2 without bleeding, conservative approaches complying with the ACCP guidelines, such as withholding warfarin or reducing its dose, were most common. In scenarios with high INRs (ie, > 7.1) and/or bleeding, the selection of vitamin K in any form ranged between 71% and 82%. However, compliance with the ACCP-recommended doses and the routes of vitamin K administration ranged from 1 to 10%. In five of the six scenarios, subcutaneous injection, a route not recommended by the ACCP, was the most common method of vitamin K delivery.

CONCLUSIONS

Physician preferences for the reversal of warfarin-induced excessive AC were highly variable and, in most cases, did not follow the recommendations of the ACCP consensus guidelines. Furthermore, the widespread reported use of subcutaneous vitamin K is concerning because this route of vitamin K administration has been demonstrated to be less effective than IV administration of vitamin K. These findings highlight the need for randomized controlled trials to compare the efficacy of different routes of administration of vitamin K for warfarin-associated coagulopathy.

The histone deacetylase inhibitor sodium butyrate induces DNA topoisomerase II alpha expression and confers hypersensitivity to etoposide in human leukemic cell lines

The differentiating agent and histone deacetylase inhibitor, sodium butyrate (NaB), was shown previously to cause a transient, 3-17-fold induction of human DNA topoisomerase II alpha (topo II alpha) gene promoter activity and a 2-fold increase in topo II alpha protein early in monocytic differentiation of HL-60 cells. This observation has now been extended to other short chain fatty acids and aromatic butyrate analogues, and evidence is presented that human topo II alpha promoter induction correlates closely with histone H4 acetylation status. Because increased topo II alpha expression is associated with enhanced efficacy of topo II-poisoning antitumor drugs such as etoposide, the hypothesis tested in this report was whether NaB pretreatment could sensitize HL-60 myeloid leukemia and K562 erythroleukemia cells to etoposide-triggered DNA damage and cell death. A 24-72 h NaB treatment (0.4-0.5 mM) induced topo II alpha 2-2.5-fold in both HL-60 and K562 cells and caused a dose-dependent enhancement of etoposidestimulated, protein-linked DNA complexes in both cell lines. At concentrations with minimal effects on cell cycle kinetics (0.4 mM in HL-60; 0.5 mM in K562), NaB pretreatment also modestly enhanced etoposidetriggered apoptosis in HL-60 cells, as determined morphologically after acridine orange/ethidium bromide staining, and substantially increased K562 growth inhibition and poly(ADP-ribose)polymerase cleavage after etoposide exposure. Therefore, a temporal window may exist whereby a differentiating agent may sensitize experimental leukemias to a cytotoxic antitumor agent. These results indicate that histone deacetylase inhibitors should be investigated for etoposide sensitization of other butyrate-responsive hematopoietic and nonhematopoietic tumor lines in vitro and in vivo.

Is intraoperative cholangiography during laparoscopic cholecystectomy cost effective?

BACKGROUND

Common bile duct injuries occur in 0.2% to 0.8% of laparoscopic cholecystectomies (LC). Intraoperative cholangiograms (IOCG) are a useful means of detecting common bile duct injuries in the operating room.

METHODS

Data were retrospectively reviewed for patients referred for management of common duct injuries from 1996 to 2000. Cost data were obtained from hospital records. Legal settlements were obtained from published sources.

RESULTS

Twenty-one patients (0.133%) were found to have bile duct injuries and incurred median hospital stays of 11.5 days at an average cost of $587,491. The average cost of those requiring reoperation was $669,134. The 21 cases in our sample had total charges of $10,819,767. Performing IOCG during each LC in Orange County would have cost $10,669,725. If extrapolated to state and nationwide levels, the savings is far greater.

CONCLUSIONS

IOCG during LC is a cost-effective means of preventing the costs of delayed recognition of bile duct injuries.

Proinflammatory chemokine induction in keratocytes and inflammatory cell infiltration into the cornea

PURPOSE

To determine the effect of interleukin (IL)-1alpha and tumor necrosis factor (TNF)-alpha on cytokine, chemokine, and receptor expression in corneal stromal cells; the effect of corneal scrape injury on monocyte chemotactic and activating factor (MCAF) expression and monocyte-macrophage influx into the stroma; and the effect of MCAF and granulocyte colony-stimulating factor (G-CSF) microinjection on inflammatory cell infiltration into the stroma.

METHODS

Gene array technology was used to evaluate changes in cytokine, chemokine, and receptor gene expression in stromal fibroblasts in response to IL-1alpha and TNFalpha. Expression of MCAF mRNA and protein was monitored with an RNase protection assay and Western blot analysis, respectively. Keratocyte MCAF protein expression in the rabbit cornea was detected with immunocytochemistry. After epithelial scrape injury, monocytes-macrophages were detected in rabbit corneas, by immunocytochemistry for monocyte-macrophage antigen. Inflammatory cell infiltration after MCAF and G-CSF microinjection into the stroma of mouse corneas was monitored with hematoxylin and eosin staining.

RESULTS

IL-1alpha or TNFalpha upregulated the expression of several proinflammatory chemokines in stromal fibroblasts in culture. These included G-CSF, MCAF, neutrophil-activating peptide (ENA-78), and monocyte-derived neutrophil chemotactic factor (MDNCF). MCAF mRNA upregulation was confirmed by RNase protection assay, and MCAF protein was detected by Western blot analysis. MCAF protein was detected in keratocytes at 4 hours and 24 hours after epithelial injury, but not in keratocytes in the unwounded cornea. Corneal epithelial injury triggered the influx of monocytes-macrophages into the corneal stroma in the rabbit. Microinjection of MCAF and G-CSF into mouse cornea resulted in the influx of monocytes-macrophages and granulocytes, respectively, into the stroma.

CONCLUSIONS

Proinflammatory chemokine induction in keratocytes is mediated by IL-1alpha and TNFalpha. The proinflammatory chemokines produced by the keratocytes probably trigger the influx of inflammatory cells into the stroma after epithelial injury associated with corneal surgery, contact lenses, or trauma.

Characterization of human and mouse angiopoietin-like factor CDT6 promoters

PURPOSE

Angiogenesis refers to the latter stage of vascular development. It has been reported that angiopoietin-like factor cornea-derived transcript 6 (CDT6) encodes a protein homologous to angiopoietins that could play a critical role in blocking a receptor of angiopoietin (Tie2) and therefore contribute to the avascularity and transparency of the cornea in the developing embryo and the adult. This study was focused on isolation and characterization of the CDT6 promoter.

METHODS

Rapid amplification of cDNA ends (5'-RACE) was used to isolate the CDT6 promoter from an adaptor-ligated genomic DNA fragment library and to identify the transcription initiation site of the CDT6 gene. The RNase protection assay was performed to confirm the initiation site. The sequence similarity, binding sites for putative transcription factors, and transcriptional activity of human and mouse CDT6 promoters were compared. Corneal and noncorneal cells from humans and other animals were transiently transfected with CDT6 promoter-chloramphenicol acetyltransferase (CAT) reporter constructs to analyze the transcriptional activity of the promoter.

RESULTS

A 2956-bp human CDT6 promoter fragment and a 3142-bp mouse CDT6 promoter fragment were isolated. The major transcription initiation sites of the human and mouse CDT6 genes were located at 224 and 168 bp, respectively, upstream of the translation initiation site. Human and mouse CDT6 promoter sequences were very similar. Both promoters were minus TATA and CAAT boxes close to the transcription initiation site. Transfection into human corneal and noncorneal cells and into nonhuman cells revealed that the human CDT6 promoter probably contains positive and negative cis-regulatory elements that modulate cell, tissue, and species specificity. The human CDT6 promoter contains four interferon (IFN)-stimulated response elements (ISREs). No ISREs could be identified in the mouse promoter. IFN-alpha stimulated transcriptional activity of the human promoter.

CONCLUSIONS

The human and mouse CDT6 promoters have similar sequences and share many cis-regulatory elements. IFN-alpha appears to have an important role in regulating transcription of the human, but not the mouse, CDT6 promoter.

Trunk posture and spinal stability

OBJECTIVE

The influence of trunk posture on musculoskeletal stability of the spine was investigated.

DESIGN

A biomechanical model was developed to evaluate the influence of posture on spinal stability. Model performance was assessed by comparing predicted muscle recruitment patterns with measured EMG activity from the trunk muscles during static lifting exertions.

METHOD

An inverted double-pendulum model of the spine controlled by 12 muscle equivalents of the trunk was implemented to determine spinal load and stability. Model input included trunk posture and lifted mass, output included muscle recruitment patterns necessary to achieve stability of the spine and spinal load. EMG activity recorded from the trunk muscles of 10 subjects were recorded during static exertions in various trunk flexion and asymmetric postures to compare with model output. Stable spinal load was examined as a function of trunk flexion and asymmetry during the lifting exertions.

RESULTS

Antagonistic co-contraction was necessary to achieve spinal stability, particularly in upright postures. Stable spinal load was increased in asymmetric postures as a result of antagonistic muscle recruitment, suggesting greater neuromuscular control is necessary to maintain stability in asymmetric lifting postures. As trunk flexion angle increased, stability improved but spinal load was greater.

CONCLUSIONS

Results illustrate that muscle recruitment patterns are more accurately explained by stability than by equilibrium alone. Spinal stability is influenced by posture. Specifically, control of spinal stability is reduced in asymmetric postures associated with low-back disorder risk.

RELEVANCE

Traditional assessment of low-back disorder risk have focussed on spinal loading. Results illustrate that postural risk factors for low-back pain may be partially attributable to stability considerations.

Laser in situ keratomileusis-induced neurotrophic epitheliopathy

PURPOSE

To report two cases of laser in situ keratomileusis-induced neurotrophic epitheliopathy with punctate epitheliopathy and rose bengal staining of the corneal flap.

METHODS

Interventional case reports.

RESULTS

A 42-year-old woman and a 37-year-old man with no preoperative symptoms or signs of dry eye developed dry eye symptoms and bilateral punctate epithelial erosions as well as rose bengal staining of the corneal flaps after laser in situ keratomileusis. Neither patient had less than 12 mm of wetting with the Schirmer test without anesthesia at any time point between development and resolution of the flap surface abnormalities. The flap surface abnormalities resolved approximately 6 months after laser in situ keratomileusis.

CONCLUSIONS

Laser in situ keratomileusis-induced neurotrophic epitheliopathy may be attributable to loss of trophic influence from severed corneal nerve trunks. The condition typically resolves approximately 6 months after laser in situ keratomileusis or laser in situ keratomileusis retreatment.

The corneal wound healing response: cytokine-mediated interaction of the epithelium, stroma, and inflammatory cells

The corneal wound healing cascade is complex and involves stromal-epithelial and stromal-epithelial-immune interactions mediated by cytokines. Interleukin-1 appears to be a master modulator of many of the events involved in this cascade. Keratocyte apoptosis is the earliest stromal event noted following epithelial injury and remains a likely target for modulation of the overall wound healing response. Other processes such as epithelial mitosis and migration, stromal cell necrosis, keratocyte proliferation, myofibroblast generation, collagen deposition, and inflammatory cell infiltration contribute to the wound healing cascade and are also likely modulated by cytokines derived from corneal cells, the lacrimal gland, and possibly immune cells. Many questions remain regarding the origin and fate of different cell types that contribute to stromal wound healing. Over a period of months to years the cornea returns to a state similar to that found in the unwounded normal cornea.

Endovascular photodynamic therapy using mono-L-aspartyl-chlorin e6 to inhibit Intimal hyperplasia in balloon-injured rabbit arteries

BACKGROUND AND OBJECTIVE

Intimal hyperplasia (IH) leading to restenosis is a major complication of arterial revascularization. The purpose of this study was to investigate the effect of photodynamic therapy (PDT) using mono-L-aspartyl chlorin e6 (NPe6) as a photosensitizer and intraluminal radial irradiation for inhibition of IH experimentally.

STUDY DESIGN/MATERIALS AND METHODS

Study of laser transmission through the blood indicated that exclusion of blood is a prerequisite for intraluminal PDT. For homogeneous radial laser irradiation to the vessel wall, we used a newly developed cylindrical diffusing balloon laser fiber. Injuries were induced by pulling a balloon catheter through the right iliac artery of rabbits. One and 6 hours after the NPe6 injection (5mg/kg i.v.), drug distribution was examined by fluorescence microscopy. Nineteen rabbits received NPe6 at the time of injuries and PDT was performed with 664-nm laser at 30 and 10 J/cm(2) (20, 30, 40 mW/cm(2)) 1 hour after the injuries. The arteries were harvested at 2 days. In a second group of rabbits, PDT was given at 30 mW/cm(2) (30 J/cm(2)). Two weeks after treatment, the arteries were removed and examined histologically.

RESULTS

NPe6 was found to be distributed selectively in the injured media. Endovascular NPe6-PDT showed complete depletion of smooth muscle cells even with 10 J/cm(2) at 2 days. IH was significantly inhibited at 14 days after PDT.

CONCLUSIONS

Endovascular PDT of injured artery using NPe6 can prevent IH in this model of arterial wall injury and may become clinically useful for the prophylaxis of IH.

Abdominal aortic aneurysm in women

OBJECTIVE

The purpose of this study was to compare abdominal aortic aneurysm (AAA) associations in men and women.

METHODS

Veterans aged 50 to 79 years without a previous history of AAA underwent ultrasound screening for AAA after completing a questionnaire on demographic information and potential risk factors.

RESULTS

A total of 122,272 men and 3450 women were successfully screened. An AAA of 3.0 cm or greater in diameter was found in 4.3% of men and 1.0% of women (P <.001). Contrary to a previous report, we did not find suprarenal aortic enlargement accompanying AAA to be more common in women. The principal associations that we have previously reported for AAA in this cohort (age, smoking, family history of AAA, and a negative association with diabetes) were all similar in women compared with men. In age- and smoking-adjusted models, the interaction terms indicated that black race and cancer were more strongly associated with AAA in women than men (P <.05). Height and cerebral vascular disease were also more strongly associated with AAA in women than in men, but these interaction terms did not reach statistical significance (P <.10). Although the other differences were unexpected and require confirmation, the trend toward a stronger association of cerebral vascular disease with AAA in women is consistent with two previous reports.

CONCLUSIONS

Despite the much lower prevalence of AAA in women, the most important associations with AAA are similar to those seen in men. Our data provide some support for a previous finding that cerebrovascular disease may be more closely associated with AAA in women than in men.

Differential expression analysis by gene array of cell cycle modulators in human corneal epithelial cells stimulated with epidermal growth factor (EGF), hepatocyte growth factor (HGF), or keratinocyte growth factor (KGF)

PURPOSE

To identify and differentiate cell cycle and differentiation genes that are up-regulated or down-regulated in human corneal epithelial cells in response to alternative epithelium-modulating cytokines epidermal growth factor (EGF), hepatocyte growth factor (HGF) or keratinocyte growth factor (KGF).

METHODS

Primary cultures human corneal epithelial cell (HCE) were treated with 25 ng/ml of EGF, 25 ng/ml HGF, 25 ng/ml KGF, or vehicle for 8 hours. Complementary DNA (cDNA) probes were synthesized from total cellular RNA isolated from the HCE cells. The cDNA probes were hybridized to the Atlas human cell cycle/differentiation array membrane. RNAse protection assay was used to confirm up-regulation of the serine/threonine-protein kinase PITALRE gene by EGF, KGF, and HGF.

RESULTS

The expression of one hundred and eleven cell cycle and differentiation genes was monitored with the gene array system. It was found that these epithelial cell-modulating cytokines shared similar effects on some of the cell cycle and differentiation genes that were monitored, but had specific effects on some cytokines. Up-regulation of PITALRE gene expression was confirmed using RNAse protection assay.

CONCLUSION

EGF, HGF and KGF had differential effects on cell cycle- and differentiation-related gene expression in corneal epithelial cells. For example, all three mitogenic growth factors up-regulated the expression of cyclin D1 (BCL-1 oncogene) and serine/threonine-protein kinase PITALRE in the primary cultured human corneal epithelial cells. However, EGF and KGF, but not HGF, up-regulated expression of the E2F-1 pRB-binding protein gene. Thus, while these three epithelial mitogens have similar effects on many genes that were analyzed, important differences were noted that may relate to differing effects of these growth factors on corneal epithelial cells. Studies to analyze the significance of the identified differences among these growth factors are in progress.

Computerized corneal topography and its importance to wavefront technology

PURPOSE

To review the development and application of corneal topography in refractive surgery.

METHODS

Review of the literature and discussion of recent developments in corneal topography and wavefront technology.

RESULTS

Analysis of corneal topography provides critical information for the preoperative examination of patients before refractive surgery and for the evaluation and treatment of patients with complications after surgery.

CONCLUSIONS

Corneal topography will continue to be a critical diagnostic modality for refractive surgery. Even with the advent of wavefront analysis designed to detect refractive error and aberrations of the eye, it will be necessary to have detailed corneal topographic information to understand the contribution the cornea makes to vision so that custom alteration of that surface can be used to optimize vision. This will be true of the normal eye, but it will be of special importance in eyes with abnormalities that were induced by corneal surgery.

Topical phenytoin treatment of stage II decubitus ulcers in the elderly

OBJECTIVE

To compare the healing of stage II decubitus ulcers with topically applied phenytoin sodium with two other standard topical treatment procedures in a long-term care setting; and to assess the extent of systemic absorption after topical application in the phenytoin group.

METHODS

Forty-seven nursing home patients with stage II decubitus ulcers were chosen for this study. The patients were matched for age, gender, and size and severity of wounds, and randomly assigned to each treatment group. Clinical assessment of decubitus ulcers was performed at the beginning of treatment and at each dressing change. Ulcers were examined for the presence of healthy granulation tissue, reduction in surface dimensions, and time to healing. Two phenytoin sodium plasma concentrations were to be obtained on all patients in the phenytoin group.

RESULTS

Topical phenytoin therapy resulted in a shorter time to complete healing and formation of granulation tissue when compared with DuoDerm dressings or triple antibiotic ointment applications (p < or = 0.05). The mean +/- SD time to healing in the phenytoin group was 35.3 +/- 14.3 days compared with 51.8 +/- 19.6 and 53.8 +/- 8.5 days for the DuoDerm and triple antibiotic ointment groups, respectively. Healthy granulation tissue in the phenytoin group appeared within two to seven days in all subjects. Patients in the standard treatment groups required six to 21 days to produce new granulation tissue. Serum phenytoin sodium concentrations were nondetectable. No patient withdrew from the study secondary to adverse treatment effects.

CONCLUSIONS

Both the phenytoin and standard treatment groups showed progress over the study period. However, the phenytoin group demonstrated more rapid results in all aspects of ulcer healing.

Laser in situ keratomileusis-induced (presumed) neurotrophic epitheliopathy

OBJECTIVE

To evaluate tear production, corneal topography, accuracy of refractive correction, and best spectacle-corrected visual acuity in eyes that had moderate to severe rose bengal staining develop on the flap compared with eyes with little or no staining on the flap, the first few months after laser in situ keratomileusis (LASIK). None of the eyes in this study had significant preoperative dry eye disease.

DESIGN

Retrospective case control study.

PARTICIPANTS

Individual eyes of 19 consecutive patients with moderate to severe punctate epithelial erosions and rose bengal staining on the flap 1 to 3 months after LASIK were compared with eyes of 19 concurrent patients who did not have punctate epithelial erosions or more than trace staining on the flap develop.

METHODS

Nonparametric statistical analyses were used to compare tear secretion, corneal topographic irregularity, spherical equivalent, and visual acuity 3 and 6 months after surgery. Some eyes in both groups also had analysis of tear secretion 1 month after surgery.

MAIN OUTCOME MEASURES

Schirmer's test without anesthesia, the topographic corneal irregularity measurement (CIM), the difference between attempted and achieved spherical equivalent, and the loss of best spectacle-corrected visual acuity.

RESULTS

There was no difference in tear production 1, 3, or 6 months after LASIK in patients who had punctate epithelial erosions and rose bengal staining on the flap develop and those who did not. There was no significant difference in the CIM or mean accuracy of the refractive correction in the two groups, but some patients had a transient decrease in best spectacle-corrected visual acuity. Flap rose bengal staining resolved by 6 months after LASIK in most affected patients.

CONCLUSIONS

LASIK-induced rose bengal staining in patients without preexisting dry eye is likely neurotrophic epitheliopathy, because there is no difference in mean tear production between patients who have significant punctate epithelial erosions and rose bengal staining develop on the flap and those who do not. The signs and symptoms of LASIK-induced (presumed) neurotrophic epitheliopathy tend to resolve approximately 6 months after surgery. This disorder tends to be more common and severe in patients with pre-existing dry eye disease.