Star-PCL shape memory polymer (SMP) scaffolds with tunable transition temperatures for enhanced utility.

Thermoresponsive shape memory polymers (SMPs) prepared from UV-curable poly(ε-caprolactone) (PCL) macromers have the potential to create self-fitting bone scaffolds, self-expanding vaginal stents, and other shape-shifting devices. To ensure tissue safety during deployment, the shape actuation temperature (i.e., the melt transition temperature or Tm of PCL) must be reduced from ∼55 °C that is observed for scaffolds prepared from linear-PCL-DA (Mn ∼ 10 kg mol-1). Moreover, increasing the rate of biodegradation would be advantageous, facilitating bone tissue healing and potentially eliminating the need for stent retrieval. Herein, a series of six UV-curable PCL macromers were prepared with linear or 4-arm star architectures and with Mns of 10, 7.5, and 5 kg mol-1, and subsequently fabricated into six porous scaffold compositions (10k, 7.5k, 5k, 10k★, 7.5k★, and 5k★) via solvent casting particulate leaching (SCPL). Scaffolds produced from star-PCL-tetraacrylate (star-PCL-TA) macromers produced pronounced reductions in Tm with decreased Mnversus those formed with the corresponding linear-PCL-diacrylate (linear-PCL-DA) macromers. Scaffolds were produced with the desired reduced Tm profiles: 37 °C < Tm < 55 °C (self-fitting bone scaffold), and Tm ≤ 37 °C (self-expanding stent). As macromer Mn decreased, crosslink density increased while % crystallinity decreased, particularly for scaffolds prepared from star-PCL-TA macromers. While shape memory behavior was retained and radial expansion pressure increased, this imparted a reduction in modulus but with an increase in the rate of degradation.

Disposition of emergency department patients with psychiatric comorbidity: results from the 2004 National Hospital Ambulatory Medical Care Survey.

BACKGROUND: Few emergency department (ED) studies have examined how psychiatric comorbidity relates to hospitalisation decisions. METHODS: We assessed the relationship of psychiatric comorbidity to hospitalisation decisions among ED patients in the 2004 National Hospital Ambulatory Medical Care Survey. RESULTS: Patients with psychiatric comorbidity were five times more likely to be hospitalised than patients with a single psychiatric diagnosis. The most frequent psychiatric comorbidities involved substance use disorders (SUDs). CONCLUSIONS: Psychiatric disorders are underdiagnosed among ED patients. We believe that this underdiagnosis may be partly responsible for the high hospitalisation rates of ED patients with SUDs.

Phosphatidylinositol 3-kinase confers resistance to encephalomyocarditis and herpes simplex virus-induced cell death through the activation of distinct downstream effectors.

The Janus kinase/STAT pathway has emerged as the paradigm of IFN-induced protection from viral infections. However, the possible participation of other signaling proteins in this protection is not clearly understood. In this report, we demonstrate that activation of phosphatidylinositol 3-kinase (PI3K) by either serum factors or IFNs blocks cell death induced by encephalomyocarditis virus (EMCV) and HSV. This increased resistance to virus-induced cell death does not involve the activation of the STAT pathway and occurs in the presence of normal viral replication. Interestingly, the cell uses two different PI3K regulated pathways to block EMCV- and HSV-induced cell death. The increased sensitivity of p85alpha(-/-) embryonic fibroblasts to EMCV-induced cell death is specifically corrected by overexpression of an activated allele of Akt/protein kinase B, but not activated mitogen-activated protein kinase extracellular kinase. Conversely, the augmented sensitivity of p85alpha(-/-) cells to HSV-induced cell death was compensated for by expression of an activated form of mitogen-activated protein kinase extracellular kinase, but not by activated Akt/protein kinase B. We conclude from these data that PI3K-activated pathways function in parallel with the Janus kinase/STAT pathway to protect cells from the lethal effects of viruses.

Dissociation between improvement in angina pectoris and myocardial perfusion after transmyocardial revascularization with an excimer laser.

Xenon chloride excimer laser transmyocardial revascularization significantly reduced angina in all patients and increased regional myocardial perfusion in most patients; however, there was no correlation between symptomatic improvement and flow improvement. Patients' symptomatic improvement preceded improved perfusion by several months.

Early experience of off-pump coronary artery bypass using Octopus Tissue Stabilizer.

OBJECTIVE: The Octopus Tissue Stabilizer stabilizes segments of the beating heart using a series of suction cups that do not damage myocardial tissue or compromise hemodynamics. This allows the heart to be positioned with the arterial target on a stable platform. In this study we present our early experience of off-pump coronary artery bypass using the Octopus Tissue Stabilizer. METHODS: Between October 1997 and June 1998, 50 patients underwent off-pump coronary artery bypass using the Octopus Tissue Stabilizer (7.5% of all coronary artery bypass cases; average age: 67.0 +/- 12.2). Preoperative ejection fraction was 15-70% (43.0 +/- 14.0%). Median sternotomy was used for all operations. RESULTS: The average number of grafts per patient was 2.5 +/- 0.9. The average operating time was 191 +/- 47 minutes. No patients returned to the operating room for postoperative bleeding or tamponade. Average intraoperative blood loss was 297 +/- 190 ml. No patient experienced perioperative myocardial infarction. There were five hospital deaths and one late death. All patients were free of angina at discharge. No patients returned with angina or required clinical restudy. CONCLUSIONS: Off-pump coronary artery bypass offers the surgeon another tool to apply for appropriate patients. The Octopus Tissue Stabilizer allows the surgeon access to all parts of coronary circulation, extending the range of off-pump coronary artery bypass procedures, when the anatomy is appropriate.

Role of the cytoplasmic domains of the type I interferon receptor subunits in signaling.

Type I interferons are imperative in maintaining a defense against viral infection. These cytokines also play an important role in the control of cell proliferation. These effects are triggered by ligand binding to a specific cell surface receptor. In the present article, we attempt to analyze the advances made in the last four years on type I interferon signaling. This review will focus on the contribution of the cytoplasmic domain of the alpha and betaL chains of the receptor to the activation of the Jak-Stat pathway. We also analyze the possible role of other pathways in interferon signaling.

Overuse of parenteral antibiotics for wound care in an urban emergency department.

This study compared patterns of parenteral antibiotic treatment by emergency physicians with literature-derived guidelines in the management of wound care. All patients who received parenteral antibiotics as part of wound management in an urban general emergency department (ED) (annual volume 65,000) and did not receive subsequent consultation or admission were prospectively studied for 4 weeks (July 18 to August 15, 1994). Data collected included age, sex, antibiotic, route of administration, dose, cost, diagnosis, and board certification of emergency physician. Antibiotic choice and dose were reviewed by study-blinded physicians and compared with criteria based on a review of the current wound care literature. Wound characteristics justifying antibiotic prophylaxis were derived from the literature and included immunocompromised patient, wounds with debris or occurring under contaminated circumstances, wounds with cellulitis or purulent drainage, wounds older than 18 hours, and crush injuries. The study included 72 patients, and 13 (18%) antibiotic discrepancies were found. Cefazolin (n = 49 [64%]) and ceftriaxone (n = 25 [35%]) were the most commonly prescribed parenteral antibiotics, with cefazolin used in 9 (69%) and ceftriaxone in 4 (31%) of discrepant cases. There were not significant differences in discrepant parenteral antibiotic by emergency physicians' board certification. There were no significant demographic differences between patients receiving discrepant and nondiscrepant antibiotics. The excess cost of discrepant parenteral antibiotics during this small study period was $380. Approximately one fifth of the parenteral antibiotics prescribed during wound care administered in the ED were discrepant with current recommendations derived from the literature.

Efficacy of low-energy T wave shocks for induction of ventricular fibrillation in patients with implantable cardioverter defibrillators.

The efficacy of low-energy T wave shocks for induction of ventricular fibrillation (VF) was evaluated in 33 patients undergoing implantable cardioverter defibrillator (ICD) implantation (33 sessions) or predischarge ICD testing (20 sessions). To induce VF, the ventricle was paced for eight cycles at a 400-ms cycle length (S1-S1), and the T wave was scanned with a monophasic shock (S2) delivered via the defibrillating lead system. Of 294 attempts, the T wave shocks induced VF in 65%, nonsustained ventricular tachycardia in 10%, and less than five ventricular beats in 25%. As compared with the failed T shocks, the mean energy of successful T wave shocks was higher and the S1-S2 coupling interval was shorter. When the S2 timing was examined in relation to the T wave peak, the VF induction efficacy was 37% for shocks delivered more than 70 ms before the T wave peak, 82% for shocks delivered 30-70 ms before the T wave peak, and 50% for shocks delivered less than 30 ms before or just after the T wave peak (P < .001). Thus, in patients undergoing ICD implantation or ICD conversion testing, the use of low-energy T wave shocks is an effective and safe method to provoke VF.

Influence of ejection fraction on hospital mortality, morbidity, and costs for CABG patients.

BACKGROUND: Preoperative ejection fraction (EF) has been shown to adversely affect postoperative hospital mortality and morbidity for patients undergoing isolated coronary artery bypass grafting. METHODS: To investigate influence of EF on isolated coronary artery bypass grafting outcomes (overall hospital mortality, hospital cardiac mortality, hospital morbidity, and hospital costs), data were reviewed from 1,354 consecutive patients who underwent isolated coronary artery bypass grafting between January 1, 1990, and April 30, 1992, at a single nonprofit hospital. Overall hospital mortality was 4.06% (cardiac, 2.36%). Hospital morbidity was 14.25% (including mortality). Hospital costs (not charges) averaged $16,673 per patient. To explore the impact of preoperative EF, EF was stratified into regular intervals. Each interval was then compared with regard to hospital mortality, morbidity, and average costs. A new statistical tool, discharge analysis, was developed to analyze the cost data. This was necessary because previous efforts at cost analysis have used tools inappropriate for real world cost data. RESULTS: The statistical analysis showed that patients with EF of 0.40 or greater had the best outcomes (lowest mortality, morbidity, and cost). Once the EF is 0.40 or greater the EF does not carry further predictive value. At EF less than 0.40, patients with EF less than 0.30 have a poorer outcome than patients with EF of 0.30 to 0.39. CONCLUSIONS: (1) Ejection fraction is a valid predictor of mortality, morbidity and resource utilization based on statistical analysis. (2) Patients can be broadly grouped as having EF greater than 0.40, less than 0.30, or from 0.30 to 0.39 with regard to clinical and cost outcomes. (3) Postoperative length of stay is not predicted by risk-adjusted EF. (4) A new tool, discharge analysis, is presented to facilitate cost analysis.

Probability of valve repair for pure mitral regurgitation.

The advantages of mitral valve repair are well established. Unfortunately, not all valves can be repaired. This presents a dilemma for the surgeon in terms of advising the patient as to the timing of operation and in decision making during operation. Patients requiring correction for pure mitral regurgitation are a heterogeneous group. By classifying the patients according to the cause of mitral regurgitation and the pathologic anatomy, we determined patterns of repair in our surgical practice for 100 consecutive patients with pure mitral regurgitation treated from January 1990 through June 1991. Patients with degenerative valve disease that spares the central portion of the anterior leaflet were likely to undergo valve repair (22/24), whereas those patients with involvement of the central portion of the anterior leaflet were likely to require replacement (15/17). This disparity may be related to the techniques of repair that were used and has spurred us to use other techniques when faced with this problem. Patients with ischemic mitral regurgitation caused by anulus dilatation were likely to undergo repair (15/17), whereas patients with ruptured papillary muscle usually underwent valve replacement (8/9). Operative mortality in this series was accurately predicted by the Parsonnet risk score. Combining knowledge of the expected operative risk and the likelihood of valve repair based on anatomic and pathologic considerations should allow the surgeon to better inform patients of their surgical options.

Pulsatile dysesthesia and an axillary artery pseudoaneurysm associated with a penetrating axillary artery injury.

A patient is presented in whom an uncommon subjective complaint of pulsatile dysesthesia (periodic dysesthesias following a radicular pattern and occurring simultaneously with the transmitted pulse) occurred following a gunshot wound to the axilla. The patient's symptoms were relieved by the surgical obliteration of a pseudoaneurysm of the axillary artery.

Endoscopic closure of bronchopleural fistulas using a tissue adhesive.

Bucrylate tissue adhesive has been found to be effective in achieving closure of surgically created bronchopleural fistulas in dogs. Success was obtained with both endoscopic and direct application. Clinical application of this method in one patient was successful [unpublished observations]. We believe that the speed, low risk, and cost-effectiveness of this approach justifies its further use in these difficult situations.