FOXO1 is a master regulator of memory programming in CAR T cells

A major limitation of chimeric antigen receptor (CAR) T cell therapies is the poor persistence of these cells in vivo1. The expression of memory-associated genes in CAR T cells is linked to their long-term persistence in patients and clinical efficacy2-6, suggesting that memory programs may underpin durable CAR T cell function. Here we show that the transcription factor FOXO1 is responsible for promoting memory and restraining exhaustion in human CAR T cells. Pharmacological inhibition or gene editing of endogenous FOXO1 diminished the expression of memory-associated genes, promoted an exhaustion-like phenotype and impaired the antitumour activity of CAR T cells. Overexpression of FOXO1 induced a gene-expression program consistent with T cell memory and increased chromatin accessibility at FOXO1-binding motifs. CAR T cells that overexpressed FOXO1 retained their function, memory potential and metabolic fitness in settings of chronic stimulation, and exhibited enhanced persistence and tumour control in vivo. By contrast, overexpression of TCF1 (encoded by TCF7) did not enforce canonical memory programs or enhance the potency of CAR T cells. Notably, FOXO1 activity correlated with positive clinical outcomes of patients treated with CAR T cells or tumour-infiltrating lymphocytes, underscoring the clinical relevance of FOXO1 in cancer immunotherapy. Our results show that overexpressing FOXO1 can increase the antitumour activity of human CAR T cells, and highlight memory reprogramming as a broadly applicable approach for optimizing therapeutic T cell states.

Dual DAT and sigma receptor inhibitors attenuate cocaine effects on nucleus accumbens dopamine dynamics in rats

Psychostimulant use disorders (PSUD) are prevalent; however, no FDA-approved medications have been made available for treatment. Previous studies have shown that dual inhibitors of the dopamine transporter (DAT) and sigma receptors significantly reduce the behavioral/reinforcing effects of cocaine, which have been associated with stimulation of extracellular dopamine (DA) levels resulting from DAT inhibition. Here, we employ microdialysis and fast scan cyclic voltammetry (FSCV) procedures to investigate the effects of dual inhibitors of DAT and sigma receptors in combination with cocaine on nucleus accumbens shell (NAS) DA dynamics in naïve male Sprague Dawley rats. In microdialysis studies, administration of rimcazole (3, 10 mg/kg; i.p.) or its structural analog SH 3-24 (1, 3 mg/kg; i.p.), compounds that are dual inhibitors of DAT and sigma receptors, significantly reduced NAS DA efflux stimulated by increasing doses of cocaine (0.1, 0.3, 1.0 mg/kg; i.v.). Using the same experimental conditions, in FSCV tests, we show that rimcazole pretreatments attenuated cocaine-induced stimulation of evoked NAS DA release but produced no additional effect on DA clearance rate. Under the same conditions, JJC8-091, a modafinil analog and dual inhibitor of DAT and sigma receptors, similarly attenuated cocaine-induced stimulation of evoked NAS DA release but produced no additional effect on DA clearance rate. Our results provide the neurochemical groundwork towards understanding actions of dual inhibitors of DAT and sigma receptors on DA dynamics that likely mediate the behavioral effects of psychostimulants like cocaine.

Regulation of immune signal integration and memory by inflammation-induced chromosome conformation

3-dimensional (3D) genome conformation is central to gene expression regulation, yet our understanding of its contribution to rapid transcriptional responses, signal integration, and memory in immune cells is limited. Here, we study the molecular regulation of the inflammatory response in primary macrophages using integrated transcriptomic, epigenomic, and chromosome conformation data, including base pair-resolution Micro-Capture C. We demonstrate that interleukin-4 (IL-4) primes the inflammatory response in macrophages by stably rewiring 3D genome conformation, juxtaposing endotoxin-, interferon-gamma-, and dexamethasone-responsive enhancers in close proximity to their cognate gene promoters. CRISPR-based perturbations of enhancer-promoter contacts or CCCTC-binding factor (CTCF) boundary elements demonstrated that IL-4-driven conformation changes are indispensable for enhanced and synergistic endotoxin-induced transcriptional responses, as well as transcriptional memory following stimulus removal. Moreover, transcriptional memory mediated by changes in chromosome conformation often occurred in the absence of changes in chromatin accessibility or histone modifications. Collectively, these findings demonstrate that rapid and memory transcriptional responses to immunological stimuli are encoded in the 3D genome.

Hispidin-enriched Sanghuangporus sanghuang mycelia SS-MN4 ameliorate disuse atrophy while improving muscle endurance

BACKGROUND

Disuse atrophy is a frequent cause of muscle atrophy, which can occur in individuals of any age who have been inactive for a prolonged period or immobilization. Additionally, acute diseases such as COVID-19 can cause frequent sequelae and exacerbate muscle wasting, leading to additional fatigue symptoms. It is necessary to investigate potent functional nutrients for muscle reinforcement in both disuse atrophy and fatigue to ensure better physical performance.

METHODS

The effects of Sanghuangporus sanghuang SS-MN4 mycelia were tested on two groups of 6-week-old male mice-one with disuse atrophy and the other with fatigue. The disuse atrophy group was divided into three sub-groups: a control group, a group that underwent hind limb casting for 7 days and then recovered for 7 days and a group that was administered with SS-MN4 orally for 14 days, underwent hind limb casting for 7 days and then recovered for 7 days. The fatigue group was divided into two sub-groups: a control group that received no SS-MN4 intervention and an experimental group that was administered with SS-MN4 orally for 39 days and tested for exhaustive swimming and running on Day 31 and Day 33, respectively. RNA sequencing (RNA-seq) and western blot analysis were conducted on C2C12 cell lines to identify the therapeutic effects of SS-MN4 treatment.

RESULTS

In a disuse atrophy model induced by hind limb casting, supplementing with 250 mg/kg of SS-MN4 for 14 days led to 111.2% gastrocnemius muscle mass recovery and an 89.1% improvement in motor function on a treadmill (P < 0.05). In a fatigue animal model, equivalent SS-MN4 dosage improved swimming (178.7%) and running (162.4%) activities (P < 0.05) and reduced blood urea nitrogen levels by 18% (P < 0.05). SS-MN4 treatment also increased liver and muscle glycogen storage by 34.36% and 55.6%, respectively, suggesting a higher energy reserve for exercise. RNA-seq and western blot studies from the C2C12 myotube showed that SS-MN4 extract upregulates Myh4 and helps sustain myotube integrity against dexamethasone damage.

CONCLUSIONS

Supplementation of SS-MN4 (250-mg/kg body weight) with hispidin as active compound revealed a potential usage as a muscle nutritional supplement enhancing muscle recovery, fast-twitch fibre regrowth and fatigue resistance.

Modular pooled discovery of synthetic knockin sequences to program durable cell therapies

Chronic stimulation can cause T cell dysfunction and limit the efficacy of cellular immunotherapies. Improved methods are required to compare large numbers of synthetic knockin (KI) sequences to reprogram cell functions. Here, we developed modular pooled KI screening (ModPoKI), an adaptable platform for modular construction of DNA KI libraries using barcoded multicistronic adaptors. We built two ModPoKI libraries of 100 transcription factors (TFs) and 129 natural and synthetic surface receptors (SRs). Over 30 ModPoKI screens across human TCR- and CAR-T cells in diverse conditions identified a transcription factor AP4 (TFAP4) construct that enhanced fitness of chronically stimulated CAR-T cells and anti-cancer function in vitro and in vivo. ModPoKI's modularity allowed us to generate an ∼10,000-member library of TF combinations. Non-viral KI of a combined BATF-TFAP4 polycistronic construct enhanced fitness. Overexpressed BATF and TFAP4 co-occupy and regulate key gene targets to reprogram T cell function. ModPoKI facilitates the discovery of complex gene constructs to program cellular functions.

An FSCV Study on the Effects of Targeted Typical and Atypical DAT Inhibition on Dopamine Dynamics in the Nucleus Accumbens Shell of Male and Female Mice

Understanding the neurochemistry underlying sex differences in psychostimulant use disorders (PSUD) is essential for developing related therapeutics. Many psychostimulants, like cocaine, inhibit the dopamine transporter (DAT), which is largely thought to account for actions related to their misuse and dependence. Cocaine-like, typical DAT inhibitors preferentially bind DAT in an outward-facing conformation, while atypical DAT inhibitors, like modafinil, prefer a more inward-facing DAT conformation. Modafinil and R-modafinil have emerged as potential therapeutic options for selected populations of individuals affected by PSUD. In addition, analogs of modafinil (JJC8-088 and JJC8-091) with different pharmacological profiles have been explored as potential PSUD medications in preclinical models. In this work, we employ fast scan cyclic voltammetry (FSCV) to probe nucleus accumbens shell (NAS) dopamine (DA) dynamics in C57BL/6 male and female mice. We find that cocaine slowed DA clearance in both male and female mice but produced more robust increases in evoked NAS DA in female mice. R-Modafinil produced mild increases in evoked NAS DA and slowed DA clearance across the sexes. The modafinil analog JJC8-088, a typical DAT inhibitor, produced increases in evoked NAS DA in female and male mice. Finally, JJC8-091, an atypical DAT inhibitor, produced limited increases in evoked NAS DA and slowed DA clearance in both sexes. In this work we begin to tease out how sex differences may alter the effects of DAT targeting and highlight how this may help focus research toward effective treatment options for PSUD.

Oxytocin receptors mediate oxytocin potentiation of methylphenidate-induced stimulation of accumbens dopamine in rats

While the illicit use and misuse of stimulants like cocaine and methylphenidate (MP) has increased, there remains no FDA-approved treatments for psychostimulant use disorders (PSUD). Oxytocin (OT) has shown promise as a potential pharmacotherapy for PSUD. Dopamine (DA) neurotransmission plays a significant role in PSUD. We have recently shown that OT blunts the reinforcing effects of MP but, surprisingly, enhanced MP-induced stimulation of DA levels. Such effects have been suggested as a result of activation of OT receptors or, alternatively, could be mediated by direct actions of OT on MP blockade of the DA transporter. Here, we employed fast scan cyclic voltammetry (FSCV) to investigate the effects of systemic OT on MP-induced changes in the dynamics of DA, phasic release and uptake, in the nucleus accumbens shell (NAS) of Sprague-Dawley rats. We also tested the systemic effects of an antagonist of OT receptors, atosiban, to counteract the OT enhancement of dopaminergic effects of MP under microdialysis procedures in the NAS in rats. Administration of OT alone (2 mg/kg; i.p.) did not significantly modify evoked NAS DA dynamics measured by FSCV, and when administered 10 min before MP (0.1, 0.3, 1.0 mg/kg; i.v.), OT did not potentiate MP-induced increases in phasic DA release and did not alter DA clearance rate, suggesting no direct interactions of OT with the MP-induced blockade of DA uptake. Also, OT alone did not elicit significant changes in tonic, extracellular NAS DA levels measured by microdialysis. However, consistent with previous studies, we observed that OT pretreatments (2 mg/kg; i.p.) potentiated MP-induced (0.1, 0.3, 1.0 mg/kg; i.v.) efflux of extracellular NAS DA levels. This effect was abolished when rats were pretreated with atosiban (2 mg/kg; i.p.), suggesting that OT receptors mediate this OT action. Overall, our results suggest that OT receptors mediated OT potentiation of MP-induced stimulation of extracellular NAS DA levels, likely driven by modulation of DA receptor signaling pathways, without affecting MP blockade of DAT.

Macrophage inflammatory and regenerative response periodicity is programmed by cell cycle and chromatin state

Cell cycle (CC) facilitates cell division via robust, cyclical gene expression. Protective immunity requires the expansion of pathogen-responsive cell types, but whether CC confers unique gene expression programs that direct the subsequent immunological response remains unclear. Here, we demonstrate that single macrophages (MFs) adopt different plasticity states in CC, which leads to heterogeneous cytokine-induced polarization, priming, and repolarization programs. Specifically, MF plasticity to interferon gamma (IFNG) is substantially reduced during S-G2/M, whereas interleukin 4 (IL-4) induces S-G2/M-biased gene expression, mediated by CC-biased enhancers. Additionally, IL-4 polarization shifts the CC-phase distribution of MFs toward the G2/M phase, providing a subpopulation-specific mechanism for IL-4-induced, dampened IFNG responsiveness. Finally, we demonstrate CC-dependent MF responses in murine and human disease settings in vivo, including Th2-driven airway inflammation and pulmonary fibrosis, where MFs express an S-G2/M-biased tissue remodeling gene program. Therefore, MF inflammatory and regenerative responses are gated by CC in a cyclical, phase-dependent manner.

Scale law of complex deformation transitions of nanotwins in stainless steel

Understanding the deformation behavior of metallic materials containing nanotwins (NTs), which can enhance both strength and ductility, is useful for tailoring microstructures at the micro- and nano- scale to enhance mechanical properties. Here, we construct a clear deformation pattern of NTs in austenitic stainless steel by combining in situ tensile tests with a dislocation-based theoretical model and molecular dynamics simulations. Deformation NTs are observed in situ using a transmission electron microscope in different sample regions containing NTs with twin-lamella-spacing (λ) varying from a few nanometers to hundreds of nanometers. Two deformation transitions are found experimentally: from coactivated twinning/detwinning (λ < 5 nm) to secondary twinning (5 nm < λ < 129 nm), and then to the dislocation glide (λ > 129 nm). The simulation results are highly consistent with the observed strong λ-effect, and reveal the intrinsic transition mechanisms induced by partial dislocation slip.

Trends in use of anti-thrombotic agents and outcomes in patients with non-ST-segment elevation myocardial infarction (NSTEMI) managed with an invasive strategy

Objective

To analyze trends in utilization of anti-thrombotic agents (ATA) and in-hospital clinical outcomes in non-ST-elevation myocardial infarction (NSTEMI) patients managed with an invasive strategy from 2007 to 2010.

Methods & results

Using ACTION Registry^®-GWTG™ data, we analyzed trends in use of ATA and in-hospital clinical outcomes among 64,199 NSTEMI patients managed invasively between 2007 and 2010. ATA included unfractionated heparin (UFH), low molecular weight heparin (LMWH), glycoprotein IIb/IIIa inhibitors (GPI) and bivalirudin. Although the proportion of NSTEMI patients treated with PCI within 48 h of hospital arrival was similar in 2007 and 2010, percentage use of bivalirudin (13.4–27.3%; p < 0.01) and UFH increased (60.0–67.5%, p < 0.01), and that of GPI (62.3–41.0%; p < 0.01) and LMWH (41.5–36.8%; p < 0.01) declined. Excess dosing of UFH (75.9–59.3%, p < 0.01), LMWH (9.6–5.2%; p < 0.01) and GPI (8.9–5.9%, p < 0.01) was also significantly lower in 2010 compared with 2007. Though in-hospital mortality rates were similar in 2007 and 2010 (2.3–1.9%, p = 0.08), the rates of in-hospital major bleeding (8.7–6.6%, p < 0.01) and non-CABG related RBC transfusion (6.3–4.6%, p < 0.01) were significantly lower in 2010 compared with 2007.

Conclusion

Compared with 2007, patients with NSTEMI, who were managed invasively in 2010 received GPI and LMWH less often and bivalirudin and UFH more frequently. There were sizeable reductions in the rates of excess dosing of UFH (though still occurred in 67% of patients), GPI and LMWH. In-hospital major bleeding complications and post-procedural RBC transfusion were lower in 2010 compared with 2007.

Hepatitis C virus upregulates B-cell receptor signaling: a novel mechanism for HCV-associated B-cell lymphoproliferative disorders

B-cell receptor (BCR) signaling is essential for the development of B cells and has a critical role in B-cell neoplasia. Increasing evidence indicates an association between chronic hepatitis C virus (HCV) infection and B-cell lymphoma, however, the mechanisms by which HCV causes B-cell lymphoproliferative disorder are still unclear. Herein, we demonstrate the expression of HCV viral proteins in B cells of HCV-infected patients and show that HCV upregulates BCR signaling in human primary B cells. HCV nonstructural protein NS3/4A interacts with CHK2 and downregulates its activity, modulating HuR posttranscriptional regulation of a network of target mRNAs associated with B-cell lymphoproliferative disorders. Interestingly, the BCR signaling pathway was found to have the largest number of transcripts with increased association with HuR and was upregulated by NS3/4A. Our study reveals a previously unidentified role of NS3/4A in regulation of host BCR signaling during HCV infection, contributing to a better understanding of the molecular mechanisms underlying HCV-associated B-cell lymphoproliferative disorders.

Accuracy of Preoperative Imaging in Detecting Nodal Extracapsular Spread in Oral Cavity Squamous Cell Carcinoma

BACKGROUND AND PURPOSE

The increasing impact of diagnosing extracapsular spread by using imaging, especially in patients with oropharyngeal squamous cell carcinoma, highlights the need to rigorously evaluate the diagnostic accuracy of imaging. Previous analysis suggested 62.5%-80.9% sensitivity and 60%-72.7% specificity. Our goals were to evaluate the accuracy of imaging in diagnosing extracapsular spread in a cohort of patients with oral cavity squamous cell carcinoma (pathologic confirmation of extracapsular spread routinely available), as a proxy for oropharyngeal squamous cell carcinoma, and to independently assess the reliability of imaging features (radiographic lymph node necrosis, irregular borders/stranding, gross invasion, and/or node size) in predicting pathologically proven extracapsular spread.

MATERIALS AND METHODS

One hundred eleven consecutive patients with untreated oral cavity squamous cell carcinoma and available preoperative imaging and subsequent lymph node dissection were studied. Two neuroradiologists blinded to pathologically proven extracapsular spread status and previous radiology reports independently reviewed all images to evaluate the largest suspicious lymph node along the expected drainage pathway. Radiologic results were correlated with pathologic results from the neck dissections.

RESULTS

Of 111 patients, 29 had radiographically determined extracapsular spread. Pathologic examination revealed that 28 of 111 (25%) had pathologically proven extracapsular spread. Imaging sensitivity and specificity for extracapsular spread were 68% and 88%, respectively. Radiographs were positive for lymph node necrosis in 84% of the patients in the pathology-proven extracapsular spread group and negative in only 7% of those in the pathologically proven extracapsular spread-negative group. On logistic regression analysis, necrosis (P = .001), irregular borders (P = .055), and gross invasion (P = .068) were independently correlated with pathologically proven extracapsular spread.

CONCLUSIONS

Although the specificity of cross-sectional imaging for extracapsular spread was high, the sensitivity was low. Combined logistic regression analysis found that the presence of necrosis was the best radiologic predictor of pathologically proven extracapsular spread, and irregular borders and gross invasion were nearly independently significant.

Walking deficits and centrophobism in an α-synuclein fly model of Parkinson's disease

Parkinson's disease (PD) is a movement neurodegenerative disorder, characterized by bradykinesia, rigidity and tremor, constituting difficulties in walking and abnormal gait. Previous research shows that Drosophila expressing human α-synuclein A30P (A30P) develop deficits in geotaxis climbing; however, geotaxis climbing is a different movement modality from walking. Whether A30P flies would exhibit abnormal walking in a horizontal plane, a measure more relevant to PD, is not known. In this study, we characterized A30P fly walking using a high-speed camera and an automatic behavior tracking system. We found that old but not young A30P flies exhibited walking abnormalities, specifically decreased total moving distance, distance per movement, velocity, angular velocity and others, compared with old control flies. Those features match the definition of bradykinesia. Multivariate analysis further suggested a synergistic effect of aging and A30P, resulting in a distinct pattern of walking deficits, as seen in aged A30P flies. Psychiatric problems are common in PD patients with anxiety affecting 40–69% of patients. Central avoidance is one assessment of anxiety in various animal models. We found old but not young A30P flies exhibited increased centrophobism, suggesting possible elevated anxiety. Here, we report the first quantitative measures of walking qualities in a PD fly model and propose an alternative behavior paradigm for evaluating motor functions apart from climbing assay.

Depletion and recovery of lymphoid subsets following morphine administration

BACKGROUND AND PURPOSE

Opioid use and abuse has been linked to significant immunosuppression, which has been attributed, in part, to drug-induced depletion of lymphocytes. We sought to define the mechanisms by which lymphocyte populations are depleted and recover following morphine treatment in mice.

EXPERIMENTAL APPROACH

Mice were implanted with morphine pellets and B- and T-cell subsets in the bone marrow, thymus, spleen and lymph nodes were analysed at various time points. We also examined the effects of morphine on T-cell development using an ex vivo assay.

KEY RESULTS

The lymphocyte populations most susceptible to morphine-induced depletion were the precursor cells undergoing selection. As the lymphocytes recovered, more lymphocyte precursors proliferated than in control mice. In addition, peripheral T-cells displayed evidence that they had undergone homeostatic proliferation during the recovery phase of the experiments.

CONCLUSIONS AND IMPLICATIONS

The recovery of lymphocytes following morphine-induced depletion occurred in the presence of morphine and via increased proliferation of lymphoid precursors and homeostatic proliferation of T-cells.

THE AUTODIGESTION HYPOTHESIS AND RECEPTOR CLEAVAGE IN DIABETES AND HYPERTENSION

One of the key features of cardiovascular complications, such as hypertension or diabetes, is that they often appear at the same time in the same individual together with other forms of co-morbidities. While clinically a recognized phenomenon, no molecular mechanism for such co-morbidities has received universal acceptance. We propose a new hypothesis that provides a molecular basis for co-morbidities in hypertension due to unchecked proteolytic activity and receptor destruction. Testing of the hypothesis in the spontaneously hypertensive rat reveals an unchecked matrix metalloproteinase and serine protease activity in plasma and on several cardiovascular and parenchymal cells. The elevated proteolytic activity causes extracellular cleavage of multiple receptor types, such that cleavage of one receptor type leads to loss of the function carried out by this receptor. Proteolytic cleavage of the extracellular domain of the β(2) adrenergic receptor in arteries and arterioles causes vasoconstriction and elevation of the central blood pressure while cleavage of the extracellular domain of the insulin receptor leads to insulin resistance and lack of transmembrane glucose transport. A diverse set of cell dysfunctions in the spontaneously hypertensive rat are accompanied by cleavage of the membrane receptors that are involved in these functions. Chronic inhibition of the unchecked protease activity in the spontaneously hypertensive rat serves to restore the extracellular receptor density and alleviates the corresponding cell dysfunctions. The mild unchecked proteolytic activity in the spontaneously hypertensive rat points towards a chronic autodigestion process as a contributor to the end organ injury encountered in this rat strain. The presence of various soluble receptors, which consist of extracellular fragments of membrane receptors, in the plasma of hypertensive and diabetic patients suggest that the autodigestion process may also be present in man.

Radiation shielding evaluation of the BNCT treatment room at THOR: a TORT-coupled MCNP Monte Carlo simulation study

This study investigates the radiation shielding design of the treatment room for boron neutron capture therapy at Tsing Hua Open-pool Reactor using "TORT-coupled MCNP" method. With this method, the computational efficiency is improved significantly by two to three orders of magnitude compared to the analog Monte Carlo MCNP calculation. This makes the calculation feasible using a single CPU in less than 1 day. Further optimization of the photon weight windows leads to additional 50-75% improvement in the overall computational efficiency.

Dalbavancin: a novel antimicrobial

The increasing incidence of serious infections because of Gram-positive pathogens and the rising cost in parenteral administration of antimicrobials has inspired the development of a novel antibiotic. Dalbavancin is the first once a week antibiotic with activity against a broad range of Gram-positive pathogens. A large multicentre, pivotal, Phase III clinical trial, which included 854 patients with complicated skin and skin structure infections, compared 1-2 doses of dalbavancin vs. linezolid. The results demonstrated non-inferiority and a comparable safety profile. With its unique pharmacokinetic profile, ease of use and excellent safety profile, dalbavancin should provide a valuable addition to the armamentarium used to treat infections because of Gram-positive cocci.

Characterization of chromatic dispersion in photonic crystal fibers using scalar modulation instability

A simple and accurate method is proposed for characterizing the chromatic dispersion of high air-filling fraction photonic crystal fibers. The method is based upon scalar modulation instability generated by a strong pump wave propagating near the zero-dispersion wavelength. Measuring the modulation instability sideband frequency shifts as a function of wavelength gives a direct measurement of the fiber's chromatic dispersion over a wide wavelength range. To simplify the dispersion calculation we introduce a simple analytical model of the fiber's dispersion, and verify its accuracy via a full numerical simulation. Measurements of the chromatic dispersion of two different types of high air-filling fraction photonic crystal fibers are presented.

Off-pump coronary artery bypass grafting decreases risk-adjusted mortality and morbidity

BACKGROUND

The purpose of this study was to determine whether coronary artery bypass grafting without cardiopulmonary bypass (off-pump CABG) decreases risk-adjusted operative death and major complications after coronary artery bypass grafting in selected patients.

METHODS

Using The Society of Thoracic Surgeons (STS) National Adult Cardiac Surgery Database, procedural outcomes were compared for conventional and off-pump CABG procedures from January 1, 1998, through December 31, 1999. Mortality and major complications were examined, both as unadjusted rates and after adjusting for known base line patient risk factors.

RESULTS

A total of 126 experienced centers performed 118,140 total CABG procedures. The number of off-pump CABG cases was 11,717 cases (9.9% of total cases). The use of an off-pump procedure was associated with a decrease in risk-adjusted operative mortality from 2.9% with conventional CABG to 2.3% in the off-pump group (p < 0.001). The use of an off-pump procedure decreased the risk-adjusted major complication rate from 14.15% with conventional CABG to 10.62% in the off-pump group (p < 0.0001). Patients receiving off-pump procedures were less likely to die (adjusted odds ratio 0.81, 95% CI 0.70 to 0.91) and less likely to have major complications (adjusted odds ratio 0.77, 95% CI 0.72 to 0.82).

CONCLUSIONS

Off-pump CABG is associated with decreased mortality and morbidity after coronary artery bypass grafting. Off-pump CABG may prove superior to conventional CABG in appropriately selected patients.

Arylcyclopropanecarboxyl guanidines as novel, potent, and selective inhibitors of the sodium hydrogen exchanger isoform-1

A novel series of arylcyclopropanecarboxyl guanidines was synthesized and evaluated for activity against the sodium hydrogen exchanger isoform-1 (NHE-1). In biological assays conducted in an AP1 cell line expressing the human NHE-1 isoform, the starting cyclopropane 3a (IC(50) = 3.5 microM) shows inhibitory activity comparable to cariporide (IC(50) = 3.4 microM). Structure-activity relationships are used to optimize the affinity of various acyl guanidines for NHE-1 by screening the effect of substituents at both aryl and cyclopropyl rings. It is demonstrated that introduction of appropriate hydrophobic groups at the phenyl ring and a gem-dimethyl group at the cyclopropane ring enhances the NHE-1 inhibitory activity by up to 3 orders of magnitude (compound 7f, IC(50) = 0.003 microM). In addition, the gem-dimethyl series of analogues seem to display improved oral bioavailability and longer plasma half-life in rats. Furthermore, the lead benzodihydrofuranyl analogue 1 (BMS-284640) shows over 380-fold increased NHE-1 inhibitory activity as well as improved selectivity for NHE-1 over NHE-2 compared to cariporide.

Pelvic embolization for treatment of hemorrhage related to spontaneous and induced abortion

OBJECTIVE

Presentation of outcomes of pelvic arterial embolization for hemorrhage after spontaneous or induced abortion.

STUDY DESIGN

We collected case reports of embolization after spontaneous or induced abortion from oral presentations and from members of the National Abortion Federation.

RESULTS

Pelvic arterial embolization was performed for 11 women who had hemorrhage after spontaneous or induced abortion, and it was initially successful for all women. One woman ultimately required a hysterectomy after unsuccessful repeated embolization. Prophylactic embolization was done for 8 women who were at risk for hemorrhage from placenta accreta; 4 of these women had subsequent hysterectomies.

CONCLUSIONS

Selective pelvic arterial embolization may be a successful treatment for hemorrhage associated with spontaneous and induced abortion. Embolization can be considered before hysterectomy is undertaken for control of hemorrhage. There may be a role for prophylactic catheterization or embolization when there is a risk of severe hemorrhage.

The development of breast carcinoma in women with thyroid carcinoma

BACKGROUND

Breast carcinoma and thyroid carcinoma are two malignancies that occur most commonly in women. An association between the incidence rates of thyroid and breast carcinoma in women after a diagnosis of the other malignancy has been suggested in a retrospective analysis of a single institution's tumor registry. In that study, an increased incidence of breast carcinoma in premenopausal women previously treated for thyroid carcinoma was observed.

METHODS

The purpose of this study was to investigate further this relation utilizing a large database, the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) database. The SEER database is maintained by the National Cancer Institute, and it represents 11 population-based cancer registries covering approximately 14% of the United States population. The study was a population-based retrospective cohort analysis using external comparisons. From 1973 to 1994, 365 women in the SEER database were identified as having both thyroid and breast carcinomas. The SEER database from 1973 to 1994 was utilized to calculate age specific and calendar year specific incidence rates for each year for thyroid and breast carcinomas. The expected number of second cancers for each age group, calendar year, and follow-up period were determined by multiplying these incidence rates by the age specific and calendar year specific number of person-years at risk. The risk ratio (RR) was calculated by dividing the observed by the expected number of second cancers. Statistical significance was determined by the Poisson test.

RESULTS

A total of 1,333,115 person-years were available for analysis. One hundred thirteen thyroid carcinoma cases were diagnosed after breast carcinoma cases (RR, 0.99; P = 0.576). Two hundred fifty-two breast carcinoma cases were diagnosed after thyroid carcinoma cases (RR, 1.18; P = 0.007). Premenopausal women (age 20-49 years) with an index thyroid carcinoma have a significantly increased risk of developing subsequent breast carcinoma (RR, 1.42; P = 0.001). Black premenopausal women with an index thyroid carcinoma do not have an increased risk of developing breast carcinoma, but the statistical power is lower due to low numbers. No women with index breast carcinoma have an increased risk of developing thyroid carcinoma.

CONCLUSIONS

Women with a history of thyroid carcinoma have a greater than expected risk of developing breast carcinoma. This risk is most pronounced in premenopausal white women. The implications of this observation with respect to breast carcinoma screening guidelines and thyroid carcinoma treatment guidelines deserve further investigation.

The development and validation of a dysphagia-specific quality-of-life questionnaire for patients with head and neck cancer: the M. D. Anderson dysphagia inventory

OBJECTIVE

To design a reliable and validated self-administered questionnaire whose purpose is to assess dysphagia's effects on the quality of life (QOL) of patients with head and neck cancer.

DESIGN

Cross-sectional survey study.

METHODS

Focus groups were convened for questionnaire development and design. The M. D. Anderson Dysphagia Inventory (MDADI) included global, emotional, functional, and physical subscales. One hundred consecutive adult patients with a neoplasm of the upper aerodigestive tract who underwent evaluation by our Speech Pathology team completed the MDADI and the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). Speech pathologists completed the Performance Status Scale for each patient. Validity and reliability properties were calculated. Analysis of variance was used to assess how well the MDADI discriminated between groups of patients.

RESULTS

The internal consistency reliability of the MDADI was calculated using the Cronbach alpha coefficient. The Cronbach alpha coefficients of the MDADI subscales ranged from 0.85 to 0.93. Test-retest reliability coefficients of the subscales ranged from 0.69 to 0.88. Spearman correlation coefficients between the MDADI subscales and the SF-36 subscales demonstrated construct validity. Patients with primary tumors of the oral cavity and oropharynx had significantly greater swallowing disability with an adverse impact on their QOL compared with patients with primary tumors of the larynx and hypopharynx (P<.001). Patients with a malignant lesion also had significantly greater disability than patients with a benign lesion (P<.001).

CONCLUSIONS

The MDADI is the first validated and reliable self-administered questionnaire designed specifically for evaluating the impact of dysphagia on the QOL of patients with head and neck cancer. Standardized questionnaires that measure patients' QOL offer a means for demonstrating treatment impact and improving medical care. The development and validation of the MDADI and its use in prospective clinical trials allow for better understanding of the impact of treatment of head and neck cancer on swallowing and of swallowing difficulty on patients' QOL.

The significance of comorbidity in advanced laryngeal cancer

INTRODUCTION

Cancer patients often have concurrent diseases and conditions known as comorbidities. The aim of this project is to demonstrate the significance of comorbidity in the treatment and outcomes of advanced laryngeal carcinoma.

METHODS

A retrospective medical record review of 182 patients with previously untreated T3 or T4 squamous carcinomas of the larynx treated at M. D. Anderson between 1990 and 1995 was performed. Demographic, patient-specific, tumor-specific, and outcome measures information were collected. Comorbidity was coded using the Modified Medical Comorbidity Index. Univariate and multivariate analysis with the use of life survival analysis techniques and logistic regression were performed.

RESULTS

The median age at diagnosis was 59.5 years. Most patients were men (69.2%) and Caucasian (73.1%). Laryngeal preservation was performed in 90 patients, and surgical resection was performed in 92 patients. Patients in the two treatment groups had similar comorbidity, locoregional control (65%), and 5-year survival (37.3%). Patients with either moderate or severe comorbidity had significantly worse overall survival (p = .00014) and worse 5-year survival than those with no or mild comorbidity (21.8% vs 46.3%, p = .003).

CONCLUSIONS

This study demonstrates that comorbidity is significantly associated with survival in a group of patients with identical histology, site, and stage. Comorbid status should be incorporated into the assessment of prognosis and outcome to improve and optimize the management of head and neck cancer patients.

Stimulation of topoisomerase II-mediated DNA damage via a mechanism involving protein thiolation

The breakage/reunion reaction of DNA topoisomerase II (TOP2) can be interrupted by DNA intercalators (e.g., doxorubicin), enzyme binders (e.g., etoposide), or DNA lesions (e.g., abasic sites) to produce TOP2-mediated DNA damage. Here, we demonstrate that thiol alkylation of TOP2 can also produce TOP2-mediated DNA damage. This conclusion is supported by the following observations using purified TOP2: (1) Thiol-reactive quinones were shown to induce TOP2-mediated DNA cleavage. (2) Thiol-reactive compounds such as N-ethylmaleimide (NEM), disulfiram, and organic disulfides [e.g., 2,2'-dithiobis(5-nitropyridine)] were also shown to induce TOP2-mediated DNA cleavage with similar reaction characteristics as thiol-reactive quinones. (3) TOP2-mediated DNA cleavage induced by thiol-reactive quinones was completely abolished using mutant yeast TOP2 with all cysteine residues replaced with alanine (cysteineless TOP2). These results suggest the possibility that cellular DNA damage could occur indirectly through thiolation of a nuclear protein, TOP2. The implications of this reaction in carcinogenesis and apoptotic cell death are discussed.

Factors associated with age at operation for children with congenital heart disease

OBJECTIVE

Previous studies have shown that children with congenital heart disease (CHD) who live in nonurban areas or who do not have private insurance are at risk for delayed referral to a pediatric cardiologist. However, the effect of these factors on the age at which cardiac surgery is performed has not been evaluated. This study is designed to evaluate the factors that influence the age at which definitive surgical repair is performed.

METHODS

Data on hospital discharges for 1995 and 1996 in California were obtained from the Office of Statewide Health Planning and Development database. Children <18 years who underwent surgical repair for atrial septal defect (ASD), ventricular septal defect (VSD), tetralogy of Fallot (TOF), or atrioventricular canal (AVC) were included in the study. Age at surgery was evaluated using type of CHD, gender, race, type of insurance, surgical centers, urban or rural home location, and distance between home and surgical center as independent variables.

RESULTS

In 1995-1996, 666 children underwent ASD closure (mean age: 5.1 years; median: 4.0 years), 582 VSD closure (mean age: 2.8; median: 1.1 years), 394 TOF repair (mean age: 1.7; median:.9 years), and 177 AVC repair (mean age: 1.1; median:.6 years). Comparing median and mean age at surgery, we found: AVC<TOF<VSD<ASD (< indicates younger than). A consistent trend for all 4 types of CHD was seen indicating that for median age at operation: private insurance<managed care<Medicaid. Gender or race had no effect on age at operation, although Asians tended to be older at surgery for all 4 types of CHD. There is a significant negative correlation between the case volume of surgical centers and median age at operation for ASD (r = -.37), VSD (r = -.49), TOF (r = -.63), and AVC (r = -.17). In addition, significant positive correlation was found between degree of urbanization of home locations (measured by population density) and median age at operation for ASD (r =.50), VSD (r =.77), and TOF (r =.18). No significant correlation was found between distance to surgical center and age at operation.

CONCLUSIONS

Many medical and nonmedical variables play important roles in determining age for definitive repair of CHD in children. Type of insurance, a recognized surrogate for access to care, may play an important role. In addition, centers with higher surgical case volume were more likely to operate at a younger age. Finally, children in urban areas tend to be older at the time of surgery for ASD, VSD, and TOF.

The impact of clinical pathways on the practice of head and neck oncologic surgery: the University of Texas M. D. Anderson Cancer Center Experience

OBJECTIVE

To assess the impact of clinical pathways on the practice of head and neck oncologic surgery in an academic center.

DESIGN

Cross-sectional study.

SETTING

Cancer treatment center.

PATIENTS

The study population consisted of 3 groups of patients who underwent unilateral neck dissection and were treated in the Department of Head and Neck Surgery of the University of Texas M. D. Anderson Cancer Center, Houston. Additional procedures which may have been performed were direct laryngoscopy, rigid esophagoscopy, and/or dental extractions. Ninety-six patients treated during 1993-1994 prior to the implementation of the clinical pathway (historical control group) were compared with 94 patients treated during 1996-1998, 64 who were not (contemporaneous nonpathway group) and 30 who were managed on the clinical pathway (pathway group). Patients from 1995 were excluded since the pathway was in the planning stages then.

MAIN OUTCOME MEASURES

Median length of stay; median total costs of care.

RESULTS

The median length of hospital stay of the historical control, contemporaneous nonpathway, and pathway groups decreased from 4.0 to 2.0 days (P<.001). The total median costs of care were less in the pathway group as compared with the historical control group ($6,227 and $8,459, respectively, P<.001) and also less in the contemporaneous nonpathway group compared with the historical control group (S6885 and $8,459, respectively, P<.001). Mean and median length of hospital stay and costs were lower in the pathway group as compared with the nonpathway group but not significantly (P = .11 and P = .07, respectively) The contemporaneous nonpathway and pathway groups did not differ in complications or readmissions.

CONCLUSIONS

Development and implementation of this clinical pathway played a statistically significant role in decreasing length of hospital stay and total costs of care associated with neck dissection between nonpathway and pathway patients. Thus, a more cost-effective practice environment has resulted for all of our patients.

Generation of T-cell immunity to a murine melanoma using MART-1-engineered dendritic cells

The murine melanoma B16 expresses the murine counterpart of the human MART-1/Melan-A (MART-1) antigen, sharing a 68.6% amino acid sequence identity. In this study, mice were vaccinated with bone marrow-derived murine dendritic cells genetically modified with a replication-incompetent adenoviral vector to express the human MART-1 gene (AdVMART1). This treatment generated a protective response to a lethal tumor challenge of unmodified murine B16 melanoma cells. The response was mediated by major histocompatibility complex class I-restricted cytotoxic T lymphocytes specific for MART-1 antigen, which produced high levels of interferon-gamma when reexposed to MART-1 in vitro and lysed targets in a calcium-dependent mechanism suggestive of perforin/granzyme B lysis. MART-1 was presented by the dendritic cells used for vaccination and not by epitopes cross-presented by host antigen-presenting cells. In conclusion, dendritic cells genetically modified to express the human MART-1 antigen generate potent murine MART-1-specific protective responses to B16 melanoma.

Characterization of antitumor immunization to a defined melanoma antigen using genetically engineered murine dendritic cells

A murine model of dendritic cell (DC)-based genetic immunization to a defined human melanoma antigen (Ag), MART-1/Melan-A (MART-1), was developed. The MART-1 gene was stably transfected into the nonimmunogenic mouse fibrosarcoma cell line NFSA that is syngeneic in C3Hf/Sem/Kam (C3H, H-2k) mice to generate the NFSA(MART1) cell line. In vivo protection from a lethal NFSA(MART1) tumor challenge could be generated by DCs transduced with a recombinant adenovirus (AdV) vector expressing MART-1 (AdVMART1). This model has the following characteristics: (a) immunological specificity and memory, (b) comparable protection for varying transduction multiplicities of infection, cell doses, and sites of DC inoculation but, interestingly, worse protection with increasing numbers of vaccinations, (c) the ability to treat small established tumors, (d) an absolute requirement for CD8 and CD4 T cells, (e) generation of MART-1-specific splenic cytotoxic T lymphocytes, and (f) up-regulation of both T helper type 1 and T helper type 2 cytokines. Genetically engineered DCs presenting defined tumor Ags represent an attractive method to generate effective immune responses.

Drug-radiation interactions in tumor blood vessels

Obliteration of the tumor vasculature is an effective means of achieving tumor regression. Antiangiogenic agents have begun to enter cancer clinical trials. Ionizing radiation activates the inflammatory cascade and increases the procoagulative state within blood vessels of both tumors and normal tissues. These responses are mediated through oxidative injury to the endothelium, leading to induction of cell-adhesion molecules and exocytosis of stored proteins from the endothelial cytoplasm. Agents that activate homeostatic responses in the endothelium can enhance thrombosis and vasculitis of irradiated tumor blood vessels. Proinflammatory and prothrombotic biological response modifiers given concurrently with ionizing radiation are known to induce vascular obliteration and necrosis of tumors. Other mechanisms of interaction between antiangiogenic agents and ionizing radiation include the direct cytotoxic effects of these agents. Interactions between drugs and radiation therapy might therefore occur at the level of the vascular endothelium. The importance of this paradigm is that the endothelium might not develop resistance to drugs or radiation because of lessened potential for mutagenesis and clonogenesis. The future design of clinical trials must consider the effects of radiation therapy on the vascular endothelium.

DNA topoisomerase I-targeting drugs as radiation sensitizers

Combination chemoradiation, alone or as an adjuvant to surgery, has been shown to improve treatment outcomes in a number of human malignancies, but may be limited by normal tissue toxicities. A primary challenge in radiation oncology is the development of drugs that can selectively enhance the cytotoxicity of ionizing radiation against tumor cells. Mammalian DNA topoisomerase I is the major cytotoxic target of a number of newly developed anticancer drugs that have shown efficacy against solid tumors, including colon cancer, ovarian cancer, lung cancer, cancer of the head and neck, and pediatric cancers. Topoisomerase I-targeting drugs exert their cytotoxic effect by producing enzyme-mediated DNA damage, rather than by directly inhibiting enzyme catalytic activity. DNA topoisomerase I recently has been established as a biochemical mediator of radiosensitization in cultured mammalian cells by camptothecin derivatives. Interestingly, this sensitization appears to be schedule-dependent, cell cycle phase-specific, cell line-dependent, and not strictly dependent on drug cytotoxicity. Clinical chemoradiation trials using camptothecin derivatives are currently ongoing. Future studies aimed at better understanding the underlying mechanisms of molecular radiosensitization with topoisomerase I-targeting drugs are pivotal to the clinical application of these agents, as well as in guiding the development of more effective radiosensitizers.

p53 selective and nonselective replication of an E1B-deleted adenovirus in hepatocellular carcinoma

An E1B gene-attenuated adenovirus (dl1520) has been proposed to have a selective cytolytic activity in cancer cells with a mutation or deletion in the p53 tumor suppressor gene (p53-null), a defect present in almost half of human hepatocellular carcinomas (HCCs). In this study, the in vitro and in vivo antitumor activity of dl1520 was investigated focusing on two human HCC cell lines, a p53-wild type (p53-wt) cell line and a p53-null cell line. dl1520 was tested for in vitro cytopathic effects and viral replication in the human HCC cell lines Hep3B (p53-null) and HepG2 (p53-wt). The in vivo antitumor effects of dl1520 were investigated in tumors grown s.c. in a severe combined immunodeficient mouse model. In addition, the combination of dl1520 infection with systemic chemotherapy was assessed in these tumor xenografts. At low multiplicities of infection, dl1520 had an apparent p53-dependent in vitro viral growth in HCC cell lines. At higher multiplicities of infection, dl1520 viral replication was independent of the p53 status of the target cells. In vivo, dl1520 significantly retarded the growth of the p53-null Hep3B xenografts, an effect augmented by the addition of cisplatin. However, complete tumor regressions were rare, and most tumors eventually grew progressively. dl1520 had no effect on the in vivo growth of the p53-wt HepG2 cells, with or without cisplatin treatment. The E1B-deleted adenoviral vector dl1520 has an apparent p53-dependent effect in HCC cell lines. However, this effect is lost at higher viral doses and only induces partial tumor regressions without tumor cures in a human HCC xenograft model.

Activation of topoisomerase II-mediated excision of chromosomal DNA loops during oxidative stress

Hydrogen peroxide (H2O2), a reactive oxygen species (ROS), is known to induce oxidative stress and apoptosis. U937 cells treated with H2O2 were shown to produce high molecular weight (HMW) DNA fragments approximately 50 to 100 kb in size in <1 min. The formation of these HMW DNA fragments is reversible and shown to be mediated by DNA topoisomerase II (TOP2). Following this initial event, formation of irreversible HMW DNA fragments and nucleosomal ladders occurs. Our results thus demonstrate a potential role of TOP2 in oxidative damage of DNA and apoptotic cell death.

Methods for creating and animating a computer model depicting the structure and function of the sarcoplasmic reticulum calcium ATPase enzyme

This paper describes the developmental process used to visualize the calcium ATPase enzyme of the sarcoplasmic reticulum. The steps involved were evaluating scientific information, consulting with scientists, model making, storyboarding, and creating and editing in a computer medium. The product was a computer-generated animation depicting the relationship between the structure and function of the sarcoplasmic reticulum calcium ATPase enzyme.

Cost-effectiveness of the diagnostic evaluation of vertigo

OBJECTIVE

To evaluate the cost-effectiveness of several diagnostic tests used in the evaluation of vertigo.

STUDY DESIGN

Cost-effectiveness analysis, using data from retrospective case review.

METHODS

Charts and test results were reviewed from 192 outpatients seen in an academic tertiary referral center for evaluation of vertigo. Cost-effectiveness analysis was performed using decision analysis software, data from office and hospital charges, and expert-based estimations of the utility of different test outcomes. Sensitivity analysis was performed using standard algorithms and wide variable ranges.

RESULTS

We found that audiologic testing, posturography, and electronystagmography were the most cost-effective tests, and that magnetic resonance imaging and blood tests had the lowest cost-effectiveness. The analysis was sensitive to the effects of financial costs of tests but, with a few exceptions, was typically not sensitive to the utility of test outcomes or the distribution of test results.

CONCLUSIONS

The use of cost-effectiveness analysis, the estimation of utility of test outcomes, and techniques of sensitivity analysis should help guide the clinician's decision making on appropriate testing for patients with vertigo.

Challenges and relevance of problem-based learning in dental education

The rôle of PBL as an innovative approach in medical education has been well documented. There has been an emerging trend of incorporating PBL into the dental curriculum. The potential advantages of PBL as a mode of learning encompass the enhancement of an integrated approach in solving dental-treatment-related problems, the development of critical thinking and problem solving skills and the encouragement of independent life-long learning. PBL was introduced into the dental curriculum as a pilot project in the Faculty of Dentistry, National University of Singapore in summer 1996. An example of a case-based study was illustrated and the learning objectives of the study were highlighted. Initial feedback from students indicated a positive attitude to this mode of learning in terms of cognitive, affective and psychomotor skills. Strategies to enhance learning in the PBL environment include time allocation for self-study, availability of resource materials and use of appropriate assessment methods. Problems that remain to be resolved include the choice of appropriate outcome assessment measures to evaluate the effectiveness of PBL as a mode of learning in undergraduate dental education.

Establishing the etiology of childhood hearing loss

The cause of hearing loss in children is often difficult to identify. We evaluated a cohort of 114 children (47 boys, 67 girls) referred with newly diagnosed hearing loss (non-otitis media) to identify factors predictive of etiology and type of hearing loss. Clinical (history and physical examination), laboratory, and radiographic data were collected. One hundred children (87.7%) had sensorineural hearing loss, and 14 (12.3%) had conductive or mixed hearing loss. The cause of hearing loss was identified in 54 children (48%). Patients with isolated aural atresia (n = 7) or with a known diagnosis of congenital cytomegalovirus infection (n = 21) were excluded from further data analysis. We conducted statistical analysis to identify factors predictive of the cause and type of hearing loss. Clinical factors that aided in identifying a cause included abnormal physical examination findings (p = 0.001) and craniofacial anomalies (p = 0.006). Computed tomography of the temporal bones was the only diagnostic test predictive of cause (p < 0.001). Factors predictive of the type of hearing loss detected (sensorineural vs. conductive or mixed) were abnormal physical examination findings (p = 0.01) and craniofacial anomalies (p = 0.004). An exhaustive laboratory or radiographic workup did not prove beneficial in identifying the etiology of hearing loss in our series.

Effect of temperature on lateral wall mechanics of the guinea pig outer hair cell

The outer hair cell is thought to enhance the sensitivity of mammalian hearing. Its lateral wall consists of 3 concentric layers: an outermost plasma membrane, a cortical lattice, and an innermost collection of flattened membranes called the subsurface cisternae. The cytoplasm requires positive pressure for full expression of the outer hair cell's electromotility. Using micropipette aspiration, we investigated the mechanics of the guinea pig's outer hair cell lateral wall at room temperature (22 degrees C) and at the guinea pig's body temperature (39 degrees C). Although there was a 10% decrease in stiffness parameter with an increase from room to body temperature, the difference was not statistically significant; values ranged from 0.45 to 0.65 dyne/cm. With sufficient negative pressure, the cytoplasmic membrane is separated from the rest of the outer hair cell's lateral wall, a process that leads to vesiculation of the plasma membrane. Vesiculation occurs at a lower pressure than at body temperature. Our results demonstrate that the stiffness parameter of the outer hair cell lateral wall at body temperature is similar to that at room temperature. However, the plasma membrane's attachment to the cortical lattice is greatly altered by temperature. The decrease in strength of membrane attachment at body temperature may result from a change in membrane fluidity, making it more easy for membrane attachment sites to break free and permit vesiculation. Whether the tethering of the plasma membrane to the cortical lattice is lost under clinically pathologic conditions deserves future study.

In search of the transfusion trigger

Red blood cell transfusions are used commonly in orthopaedic surgery and cost billions of dollars annually. The goals of transfusion are to reduce mortality and morbidity and improve functional status that result from anemia and inadequate O2 delivery. Risks of infections from transfusion are low and continue to decline, but evidence is growing that red cell transfusions are immunosuppressive and predispose patients to postoperative infections. However, there actually are very little data on when transfusion is indicated. Observational data suggest that transfusion does not reduce mortality in patients with preoperative or postoperative hemoglobin levels 8 g/dL or greater, although no conclusions could be drawn about the effect of transfusion in patients with hemoglobin 8 g/dL or less. Large, well performed randomized clinical trials are needed to establish the efficacy of transfusion. Until better data are available, orthopaedic surgeons will have to rely on clinical judgement in decisions regarding transfusions. Using a higher transfusion threshold in patients with cardiovascular disease is recommended.

Outcomes analysis of voice and quality of life in patients with laryngeal cancer

OBJECTIVE

To assess relationships between voice satisfaction and global quality of life in patients who have been treated for laryngeal cancer.

DESIGN

Cross-sectional survey study.

SETTING

Veterans Affairs Medical Center.

PATIENTS

Eighty patients who had completed treatment for laryngeal cancer with either total laryngectomy (n=17), radiotherapy (n=24), or both (n=39).

MAIN OUTCOME MEASURES

Subscale scores on a general health status instrument (the Medical Outcomes Study 36-item short-form health survey), and a validated voice-specific functional status instrument (the Voice Handicap Index).

RESULTS

Self-rated global health did not correlate significantly with emotional, functional, or physical voice handicap, although some subscales on the 36-item short-form health survey correlated with voice handicap scores. Global health status scores did not differ between patients who had undergone laryngectomy with a tracheoesophageal puncture and patients treated with radiotherapy only. Physical voice handicap scores did not differ significantly between those who underwent tracheoesophageal puncture and those who had radiotherapy, but emotional (P=.07) and functional (P=.01) handicap scores were lower in patients treated with radiotherapy. However, there was considerable overlap in voice handicap scores, with many patients who had had tracheoesophageal puncture showing less voice handicap than patients treated with radiotherapy.

CONCLUSIONS

These data demonstrate that health status is affected by other factors than voice handicap in patients with laryngeal cancer. In addition, there is a large amount of individual variation in voice handicap after treatment. These findings illustrate the need for prospective studies assessing voice handicap and quality of life after treatment for laryngeal cancer.

Growing use of laparoscopic cholecystectomy in the national Veterans Affairs Surgical Risk Study: effects on volume, patient selection, and selected outcomes

OBJECTIVE

To study the introduction of laparoscopic cholecystectomy to the 43 tertiary-care university-affiliated Veterans Administration medical centers (VAMCs) participating in the National Veterans Affairs Surgical Risk Study from October 1991 through December 1993.

SUMMARY BACKGROUND DATA

Previous studies in the private sector have documented growth in the number of cholecystectomies and falling clinical thresholds for cholecystectomy with the introduction of laparoscopic cholecystectomy.

METHODS

The following were analyzed for changes over time: measures of patient preoperative risk, complexity of surgery, severity of biliary disease, numbers of procedures, postoperative length of stay, and 30-day postoperative mortality and general complication rates.

RESULTS

The number of cholecystectomies performed laparoscopically increased, but the total number of cholecystectomies performed remained stable over time. The proportion of patients with acute cholecystitis, emergent cholecystectomies, and technically complex cholecystectomies did not change or increased slightly over time. Adjusted odds for postoperative general complications were lower for laparoscopic than for open cholecystectomy, but 30-day postoperative mortality and general complication rates for all cholecystectomies remained constant over time. Postoperative length of stay for all cholecystectomies fell significantly. Implementation rates of laparoscopic cholecystectomy varied widely between hospitals. Laparoscopic cholecystectomy was adopted more slowly and used in a lower percentage of cholecystectomies than in non-VA settings.

CONCLUSIONS

In contrast to non-VA studies showing increases in overall cholecystectomy volume since the introduction of laparoscopic cholecystectomy, these VAMCs implemented laparoscopic cholecystectomy without growth in cholecystectomies or a change in the clinical threshold for cholecystectomy. Laparoscopic cholecystectomy was associated with better outcomes, but its introduction in the setting of stable cholecystectomy volume and biliary disease case mix did not change postoperative mortality and complication rates. The stable cholecystectomy volume and biliary disease case mix, slower adoption, and lower use of laparoscopic cholecystectomy contrast with previous reports and may result from differences in patients and organization and financing of VA versus non-VA settings.

Genetic immunization for the melanoma antigen MART-1/Melan-A using recombinant adenovirus-transduced murine dendritic cells

Dendritic cells (DCs) are professional antigen-presenting cells that process and present antigenic peptides and are capable of generating potent T-cell immunity. A murine tumor model was developed to evaluate methods of genetic immunization to the human MART-1/Melan-A (MART-1) melanoma antigen. A poorly immunogenic murine fibrosarcoma line (NFSA) was stably transfected with the MART-1 gene. This transfected tumor [NFSA(MART1)] grows progressively in C3Hf/Kam/Sed (H-2k) mice. Partial protection against a challenge with NFSA(MART1) could be achieved with i.m. injections of a MART-1 expression plasmid or with systemic administration of an adenovirus vector expressing MART-1. However, superior protection was achieved when granulocyte macrophage colony-stimulating factor/interleukin-4-differentiated murine DCs transduced with an adenovirus vector expressing MART-1 were used for immunization. Both partial and complete protection could be achieved with i.v. administration of MART-1-engineered DCs. Splenocytes from immunized mice contained MHC class 1-restricted CTLs specific for MART-1. This preclinical model of genetic immunization supports a therapeutic strategy for human melanoma.