The evolution and social cost of herding mentality promote cooperation

Herding behavior has a social cost for individuals not following the herd, influencing human decision-making. This work proposes including a social cost derived from herding mentality into the payoffs of pairwise game interactions. We introduce a co-evolutionary asymmetric model with four individual strategies (cooperation vs. defection and herding vs. non-herding) to understand the co-emergence of herding behavior and cooperation. Computational experiments show how including herding costs promotes cooperation by increasing the parameter space under which cooperation persists. Results demonstrate a synergistic relationship between the emergence of cooperation and herding mentality: the highest cooperation is achieved when the herding mentality also achieves its highest level. Finally, we study different herding social costs and its relationship to cooperation and herding evolution. This study points to new social mechanisms, related to conformity-driven imitation behavior, that help to understand how and why cooperation prevails in human groups.

Influence Cascades: Entropy-Based Characterization of Behavioral Influence Patterns in Social Media

Influence cascades are typically analyzed using a single metric approach, i.e., all influence is measured using one number. However, social influence is not monolithic; different users exercise different influences in different ways, and influence is correlated with the user and content-specific attributes. One such attribute could be whether the action is an initiation of a new post, a contribution to a post, or a sharing of an existing post. In this paper, we present a novel method for tracking these influence relationships over time, which we call influence cascades, and present a visualization technique to better understand these cascades. We investigate these influence patterns within and across online social media platforms using empirical data and comparing to a scale-free network as a null model. Our results show that characteristics of influence cascades and patterns of influence are, in fact, affected by the platform and the community of the users.

Inferring models of opinion dynamics from aggregated jury data

Jury deliberations provide a quintessential example of collective decision-making, but few studies have probed the available data to explore how juries reach verdicts. We examine how features of jury dynamics can be better understood from the joint distribution of final votes and deliberation time. To do this, we fit several different decision-making models to jury datasets from different places and times. In our best-fit model, jurors influence each other and have an increasing tendency to stick to their opinion of the defendant’s guilt or innocence. We also show that this model can explain spikes in mean deliberation times when juries are hung, sub-linear scaling between mean deliberation times and trial duration, and unexpected final vote and deliberation time distributions. Our findings suggest that both stubbornness and herding play an important role in collective decision-making, providing a nuanced insight into how juries reach verdicts, and more generally, how group decisions emerge.

The myopia of crowds: Cognitive load and collective evaluation of answers on Stack Exchange

Crowds can often make better decisions than individuals or small groups of experts by leveraging their ability to aggregate diverse information. Question answering sites, such as Stack Exchange, rely on the “wisdom of crowds” effect to identify the best answers to questions asked by users. We analyze data from 250 communities on the Stack Exchange network to pinpoint factors affecting which answers are chosen as the best answers. Our results suggest that, rather than evaluate all available answers to a question, users rely on simple cognitive heuristics to choose an answer to vote for or accept. These cognitive heuristics are linked to an answer’s salience, such as the order in which it is listed and how much screen space it occupies. While askers appear to depend on heuristics to a greater extent than voters when choosing an answer to accept as the most helpful one, voters use acceptance itself as a heuristic, and they are more likely to choose the answer after it has been accepted than before that answer was accepted. These heuristics become more important in explaining and predicting behavior as the number of available answers to a question increases. Our findings suggest that crowd judgments may become less reliable as the number of answers grows.

Competing opinions and stubborness: Connecting models to data

We introduce a general contagionlike model for competing opinions that includes dynamic resistance to alternative opinions. We show that this model can describe candidate vote distributions, spatial vote correlations, and a slow approach to opinion consensus with sensible parameter values. These empirical properties of large group dynamics, previously understood using distinct models, may be different aspects of human behavior that can be captured by a more unified model, such as the one introduced in this paper.

Association between adherence to folic acid supplements and serum folate, and plasma homocysteine among hemodialysis patients

OBJECTIVE

To examine the relationship between adherence to prescribed folic acid supplements and folic acid intake, serum folate and plasma homocysteine in hemodialysis patients. The effects of change in adherence patterns from enrollment to 1 year later on changes in these same measures were also assessed.

DESIGN

Secondary data analysis.

PARTICIPANTS

Eighty-six hemodialysis patients who participated in the Hemodialysis (HEMO) Study's Homocysteine ancillary study.

MAIN OUTCOME MEASURES

Folic acid supplement intake, serum folate, and plasma homocysteine.

RESULTS

Eighty-eight percent of patients at enrollment and 91% 1 year later were adherent to prescribed folic acid supplements. Nonadherers had lower intakes of folic acid at both enrollment and 1 year later and lower serum folate levels at enrollment. Percent change was significantly different between the 3 adherence change groups for folic acid intake (P = .001) and plasma homocysteine (P < .001) from enrollment to 1 year later. The nonadherent group at enrollment had the lowest intakes and serum folate levels, and the highest plasma homocysteine levels. When they became adherent 1 year later, they had the greatest change in folic acid intake (5,461%; P = .03), coupled with a 69% increase in serum folate (P = .04) and a 29% decrease in plasma homocysteine (P = .03).

CONCLUSIONS

Hemodialysis patients who were nonadherent to folic acid supplement prescriptions had low folic acid intakes, low serum folates, and high homocysteine levels. When their adherence improved, folic acid intakes rose, serum folates increased, and plasma homocysteine levels decreased, although mild hyperhomocysteinemia persisted.

The Problem with Zoning: Nonlinear Effects of Interactions between Location Preferences and Externalities on Land Use and Utility

An important debate in the literature on exurban sprawl is whether low-density development results from residential demand, as operationalized by developers, or from exclusionary zoning policies. Central to this debate is the purpose of zoning, which could alternatively be a mechanism to increase the utility of residents by separating land uses and reducing spillover effects of development, or an obstacle to market mechanisms that would otherwise allow the realization of residential preferences. To shed light on this debate, we developed an agent-based model of land-use change to study how the combined effects of zoning-enforcement levels, density preferences, preference heterogeneity, and negative externalities from development affect exurban development and the utility of residents. Our computational experiments show that sprawl is not inevitable, even when most of the population prefers low densities. The presence of negative externalities consistently encourage sprawl while decreasing average utility and flattening the utility distribution. Zoning can reduce sprawl by concentrating development in specific areas, but in doing so decreases average utility and increases inequality. Zoning does not internalize externalities; instead, it contains externalities in areas of different development density so that residents bear the burden of the external effects of the density they prefer. Effects vary with residential preference distributions and levels of zoning enforcement. These initial investigations can help inform policy makers about the conditions under which zoning enforcement is preferable to free-market development and vice versa. Future work will focus on the environmental impacts of different settlement patterns and the role land-use and market-based policies play in this relationship.

Folic acid supplementation and cardiac and stroke mortality among hemodialysis patients

OBJECTIVE

We sought to assess whether the use of folic acid vitamin supplements reduced cardiac and stroke mortality in hemodialysis patients. Further, we examined whether the consumption of folic acid from vitamin supplements >1000 microg compared with the standard 1000 microg, and 1000 microg compared with either a lower dose or no consumption, were associated with reduced cardiac and stroke mortality risk.

DESIGN

We performed a secondary analysis of data from the Hemodialysis Study, a randomized clinical trial examining dialysis treatment regimens over a 3-year follow-up.

PARTICIPANTS

Participants included 1846 hemodialysis patients previously participating in the Hemodialysis Study.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURE

Cardiac and stroke mortality were our main outcome measures.

RESULTS

Based on time-dependent Cox proportional hazard regression models, folic acid consumption from vitamin supplements, above or below the standard 1000-microg dose, was not associated with a decrease or increase in cardiac mortality (P = .53, above vs. standard dose; P = .46, below vs. standard dose). There was also no association between folic acid consumption and mortality from stroke (P = .27, above vs. standard dose; P = .64, below vs. standard dose).

CONCLUSION

The consumption of higher than the standard 1000-microg prescribed dose of folic acid was not beneficial in reducing cardiac or stroke mortality in hemodialysis patients. Similarly, the consumption of less than the standard dose was not associated with an increase in either cardiac or stroke mortality.

The effect of recipient cytokine gene polymorphism on cardiac transplantation outcome

We determined the association between clinical outcomes after heart transplantation and gene polymorphism in five cytokines (tumor necrosis factor-alpha, transforming growth factor (TGF)-beta, interleukin-10, interleukin-6, and interferon-gamma) reported to influence expression in vitro. Ninety-five patients were studied. Cytokine genotyping was performed by sequence specific priming polymerase chain reaction. Clinical outcomes studied in the first posttransplant year included: (1) documented viral, bacterial, or fungal infection; (2) cytomegalovirus infection; (3) acute cellular rejection (International Society for Heart and Lung Transplantation > or = grade IIIA); (4) time to first rejection episode; and (5) the development of allograft vasculopathy. Patients with the TGF-beta genotype 10 T/T 25 G/G or 10 T/C 25 G/G had a longer time to first rejection (median time to first rejection episode 321 days) than those with the TGF-beta genotype 10C/C 25 G/C or 10 C/C 25 C/C (median time to first rejection 88 days). There was a trend toward a higher frequency of the tumor necrosis factor-alpha genotype -308 G/A or A/A in patients without infection (19/59, 32%) as compared with patients with infection (5/31, 16%). In both cases, these differences failed to reach significance when adjusted for multiple comparisons. No other significant association was found with clinical outcomes and polymorphisms in the five cytokine genes studied in this population.

Assessment of Sources of Second-Hand Smoke Exposure in a Putatively Unexposed Population

The authors sought to determine levels of urinary cotinine and its association with collateral exposure to second-hand smoke in public health workers. Urinary cotinine was measured twice at 1-wk intervals in 28 public health workers or their spouses. Information on sources of second-hand smoke exposure and a dietary history were obtained from each participant. Geometric mean and median cotinine levels were 2.74 and 2.33 ng/mL, respectively. Only 6 instances of second-hand smoke exposure were reported from a combined 204 days of potential exposure, and these did not correspond to higher cotinine values. There was no association between consumption of foods containing nicotine and log-transformed urine cotinine levels (p = .80). The authors' analysis indicates dietary sources of nicotine are not important, even for persons with very low urinary cotinine levels. Further study is needed to determine sources of variation in urinary cotinine among largely unexposed populations.

Randomized, Controlled Evaluation of Short- and Long-Term Benefits of Heart Failure Disease Management Within a Diverse Provider Network

Background— Several trials support the usefulness of disease management (DM) for improving clinical outcomes in heart failure (HF). Most of these studies are limited by small sample size; absence of concurrent, randomized controls; limited follow-up; restriction to urban academic centers; and low baseline use of effective medications.

Methods and Results— We performed a prospective, randomized assessment of the effectiveness of HF DM delivered for 90 days across a diverse provider network in a heterogeneous population of 200 patients with high baseline use of approved HF pharmacotherapy. During a 90-day follow-up, patients randomized to DM experienced fewer hospitalizations for HF [primary end point, 0.55±0.15 per patient-year alive versus 1.14±0.22 per patient-year alive in control subjects; relative risk (RR), 0.48, P =0.027]. Intervention patients experienced reductions in hospital days related to a primary diagnosis of HF (4.3±0.4 versus 7.8±0.6 days hospitalized per patient-year; RR, 0.54; P <0.001), cardiovascular hospitalizations (0.81±0.19 versus 1.43±0.24 per patient-year alive; RR, 0.57; P =0.043), and days in hospital per patient-year alive for cardiovascular cause (RR, 0.64; P <0.001). Intervention patients showed a trend toward reduced all-cause hospitalizations and total hospital days. On long-term (mean, 283 days) follow-up, there was substantial attrition of the 3-month gain in outcomes, with sustained significant reduction only in days in hospital for cardiac cause.

Conclusions— In a population with high background use of standard HF therapy, a DM intervention, uniformly delivered across varied clinical sites, produced significant short-term improvement in HF-related clinical outcomes. Longer-term benefit likely requires more active chronic intervention, even among patients who appear clinically stable.

Enalapril treatment and hospitalization with atrial tachyarrhythmias in patients with left ventricular dysfunction

BACKGROUND

Experimental and clinical evidence suggests a preventive role for agiotensin-coverting enzyme (ACE) inhibitors on the development of atrial fibrillation. However, the effect of ACE inhibition on hospitalization with atrial tachyarrhythmias in patients with left ventricular (LV) dysfunction is not known. We sought to determine whether enalapril treatment reduced hospitalizations with atrial tachyarrhythmias in patients with LV dysfunction.

METHODS

We performed a retrospective analysis of the Studies of Left Ventricular Dysfunction (SOLVD) trial. Hospitalizations with atrial tachyarrhythmias were noted.

RESULTS

A total of 192 hospitalizations with atrial tachyarrhythmias occurred in 158 patients during a follow-up period of 34 months. The time to first hospitalization with atrial tachyarrhythmias or death was significantly lower in the enalapril group (P =.005). In a multivariate analysis adjusting for the presence of atrial fibrillation at study entry, enalapril treatment was associated with a reduction in the rate of hospitalization with atrial tachyarrhythmias or death (RR, 0.87; 95% CI, 0.79-0.96; P =.007). The incidence of hospitalization with atrial tachyarrhythmias was 7.9 hospitalizations per 1000 patient-years of follow-up in the enalapril group, compared with 12.4 per 1000 patient-years in the placebo group (RR, 0.64; 95% CI, 0.48-0.85; P =.002).

CONCLUSION

Enalapril is associated with a decreased incidence of hospitalization with atrial tachyarrhythmias in patients with LV dysfunction.

Lipopolysaccharide induces type 2 iodothyronine deiodinase in the mediobasal hypothalamus: implications for the nonthyroidal illness syndrome

To determine whether the type 2 iodothyronine deiodinase (D2), the principal central nervous system enzyme converting T(4) to biologically active T(3), is regulated in tanycytes by immune activation, D2 activity was measured in the mediobasal hypothalamus (MBH) 4, 12, and 24 h after administration of bacterial lipopolysaccharide (LPS) and compared with D2 levels in the cortex and anterior pituitary of rats. In contrast to D2 activity in the cortex and anterior pituitary that showed a steady linear increase over 24 h, which was coincident with a decline in thyroid hormone and TSH levels, D2 activity peaked in the MBH 12 h after LPS administration. By in situ hybridization, the increased D2 mRNA synthesis induced by LPS was specifically localized to tanycytes lining the third ventricle. In vitro assays in HC11 and HEK-293 cells demonstrated that the p65 subunit of nuclear factor-kappaB markedly increased both rat and human D2 genes (dio2) as analyzed by promoter assays. No activation of human dio2 was observed when an 83-bp minimal promoter was used. We propose that LPS or LPS-induced cytokines directly induce D2 mRNA in tanycytes. The ensuing MBH-specific D2-mediated local thyrotoxicosis may suppress the hypothalamus-pituitary-thyroid axis by local feedback inhibition of hypophysiotropic TRH and/or TSH and contribute to the mechanism of central hypothyroidism associated with infection.

Comparison of survival and other complications after heart transplantation in patients taking amiodarone before surgery versus those not taking amiodarone

Concern exists regarding preoperative amiodarone use and complications occurring after heart transplantation (HT). During a 10-year period of performing HT, we found that patients treated with amiodarone before undergoing HT had decreased overall survival, required longer periods of ventilatory support, and were at increased risk for significant bleeding complications. These findings raise further concern about the use of amiodarone treatment in patients with heart failure before undergoing HT.

Diagnostic value of ultrasonography in differentiating enteritis from intestinal neoplasia in dogs

One hundred and fifty dogs with histopathologically confirmed intestinal disease were evaluated retrospectively. Sixty-one dogs had enteritis and 89 dogs had intestinal neoplasia. Ultrasonographic findings including the thickness and distribution of the intestinal lesion, the integrity of intestinal wall layering, regional lymph node thickness, the location of the intestinal segment involved, and regional motility were evaluated. Dogs with intestinal tumor had wall thickness (1.5 cm) significantly greater than dogs with NSE lesions (0.6 cm; p < 0.001). Ninety-nine percent of dogs with intestinal tumor had loss of wall layering while 88% of dogs with NSE had normal or altered wall layering (p < 0.001). Dogs with NSE were significantly more likely to have diffuse lesion (72%) than dogs with intestinal tumor (2%; p < 0.001). Lymph node median thickness in 24/61 dogs with NSE was 1.00 cm. The median thickness of the lymph nodes in 56/89 dogs with intestinal tumors was 1.9 cm. A multivariate analysis showed that loss of wall layering alone was an excellent predictive factor in differentiating intestinal tumor from NSE. In our population, dogs with loss of intestinal wall layering were 50.9 times more likely to have a tumor than enteritis.

Statin use is associated with enhanced collateralization of severely diseased coronary arteries

BACKGROUND

The presence of coronary collateral vessels has been associated with improved clinical outcome in patients with coronary artery disease. Animal experiments have shown that hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins) can promote angiogenesis in ischemic tissues in a cholesterol-independent manner. We hypothesized that statin therapy is associated with increased coronary collateral formation in patients with severe coronary artery disease.

METHODS AND RESULTS

Patients undergoing clinically indicated coronary angiography at the Tufts-New England Medical Center from September 2000 to April 2001 who had at least 1 major coronary artery occlusion, or a stenosis of > or =95% with Thrombolysis In Myocardial Infarction (TIMI) trial grade < or =1 anterograde flow on their angiograms, were included. Fifty-one patients were taking statins before admission, and 43 patients were not. Their angiograms were reviewed and coronary collaterals were graded from 0 to 3 according to the Cohen-Rentrop method. The statin-treated group had a significantly higher mean collateral score compared with the patients not taking statins (2.05 vs 1.52, P =.005). Multivariate analysis supported the significance of the effect of statin therapy on the collateral score. There was no relation between collateral score and low-density lipoprotein levels (r = -0.06, P =.64). The statin-treated group also had a significantly higher left ventricular ejection fraction compared to the patients not taking statins (51% vs 44%, P <.05).

CONCLUSIONS

Statin therapy is associated with enhanced coronary collateral formation in patients with severely diseased coronary arteries.

Risk Factors and Prognostic Variables for Survival of Foals with Radiographic Evidence of Pulmonary Disease

The medical records of 163 neonatal foals that had thoracic radiographs taken within 48 hours of admission to a referral hospital were reviewed. The objectives of this study were (1) to identify risk factors for the development of thoracic radiographic changes and (2) to identify prognostic indicators for survival in foals with radiographic evidence of pulmonary disease. Failure of transfer of passive immunity (IgG concentration < or = 400 mg/dL) was the only risk factor for radiographic evidence of respiratory disease identified by multivariate analysis. Hypoxemic patients (PaO2 < or = 60 mm Hg) were 4.9 times more likely to reveal radiographic abnormalities in a subset of foals for which arterial blood gas results were available. Foals with a serum creatinine concentration > 1.7 mg/dL upon presentation, dyspnea, and a history of dystocia were significantly more likely to die based on the multivariate statistical outcome analysis. An anion gap > or = 20 mEq/dL was strongly associated with nonsurvival in a subset of foals with arterial blood gas results. These hematologic and biochemical variables can be readily obtained during the initial evaluation of sick foals. The presence of a high anion gap appeared to have the greatest clinical impact and may be a useful prognostic indicator in foals with radiographic evidence of respiratory disease. In contrast, the majority of physical examination variables, including evaluation of tachypnea, abnormal respiratory sounds, fever, weakness, and milk reflux from the nares, which are usually obtained during the general respiratory evaluation of foals, were unrelated to outcome.

Clinical and Prognostic Significance of Radiographic Pattern, Distribution, and Severity of Thoracic Radiographic Changes in Neonatal Foals

A total of 207 thoracic radiographs obtained from 128 foals were evaluated to assess the impact of pulmonary radiographic pattern, distribution, and severity of pulmonary changes on short-term survival of neonatal foals. The association between selected clinical variables and the radiographic manifestation of neonatal respiratory disease was also investigated. The evaluation of interstitial and alveolar-interstitial radiographic patterns within the caudodorsal, caudoventral, and cranioventral lung regions proved to be highly reliable between viewers in the study. A diagnosis of systemic inflammatory response syndrome was related to increased pulmonary infiltrates within the caudodorsal lung region. Dyspneic foals had more extensive pulmonary infiltrates within the cranioventral lung, advanced respiratory disease, and lower survival rates. A fibrinogen concentration >400 mg/dL was associated with increased cranioventral radiographic abnormalities. In addition, tachypnea most consistently related to diffuse (caudodorsal, caudoventral, and cranioventral) pulmonary changes. Neutropenia, milk reflux from the nares, upper airway pathology, abnormal respiratory sounds, failure of transfer of passive immunity (IgG concentration <400 mg/dL), immaturity, or fever, however, were not related to radiographic pattern, distribution, or severity of radiographic changes. Sixty-five percent of foals with radiographic pulmonary disease were discharged alive from our referral hospital. Concurrent caudodorsal and caudoventral radiographic disease was most frequently observed in this foal population. Increased caudodorsal radiographic scores retained statistical significance as a prognostic indicator for nonsurvival in a multiple stepwise logistic regression analysis.

Generalization in response to mate recognition signals

Females usually exhibit strong and unequivocal recognition of conspecific mating signals and reject those of other sympatric heterospecifics. However, most species are allopatric with one another, and the degree to which females recognize mating signals of allopatric species is more varied. Such mating signals are often rejected but are sometimes falsely recognized as conspecific. We studied the dynamics of mate recognition in female túngara frogs (Physalaemus pustulosus) in response to a series of calls that were intermediate between the conspecific and each of five allopatric-heterospecific calls: two that elicited recognition from females in previous studies and three that did not. This study shows that females perceive variation in allopatric mating signals in acontinuous manner with no evidence of perceptual category formation. The strength of recognition is predicted by how different the target stimulus is from the conspecific call within a series of calls. But the differences in recognition responses among call series are not predicted by the similarity of the call series to the conspecific call. The latter result suggests that the strength of recognition of allopatric signals might be influenced by processes of stimulus generalization and past evolutionary history.

Erratum to: Traffic injury data, policy, and public health: Lessons from Boston Chinatown

In the March 2002 issue, the following credit line was omitted from Fig. 1(a) on p. 90 (Brugge D, Lai Z, Hill, C, Rand W. Traffic Injury Data, Policy, and Public Health: Lessons from Boston Chinatown. J Urban Health. 2002;79(1):87-103): "This figure is reprinted with permission from Brugge D, A Leong, Z Lai. Can a community inject public health values into transportation questions? Public Health Rep. 1999:114:44."

Binge eating disorder in extreme obesity

OBJECTIVE

To determine whether extremely obese binge eating disorder (BED) subjects (BED defined by the Eating Disorder Examination) differ from their extremely obese non-BED counterparts in terms of their eating disturbances, psychiatric morbidity and health status.

DESIGN

Prospective clinical comparison of BED and non-BED subjects undergoing gastric bypass surgery (GBP).

SUBJECTS

Thirty seven extremely obese (defined as BMI > or = 40 kg/m(2)) subjects (31 women, six men), aged 22-58 y.

MEASUREMENTS

Eating Disorder Examination 12th Edition (EDE), Three Factor Eating Questionnaire (TFEQ), Structured Clinical Interview for the Diagnostic and Statistical Manual-IV (SCID-IV), Short-Form Health Status Survey (SF-36), and 24 h Feeding Paradigm.

RESULTS

Twenty-five percent of subjects were classified as BED (11% met full and 14% partial BED criteria) and 75% of subjects were classified as non-BED. BED (full and partial) subjects had higher eating disturbance in terms of eating concern and shape concern (as found by the EDE), higher disinhibition (as found by the TFEQ), and they consumed more liquid meal during the 24 h feeding paradigm. No difference was found in psychiatric morbidity between BED and non-BED in terms of DSM-IV Axis I diagnosis. The health status scores of both BED and non-BED subjects were significantly lower than US norms on all subscales of the SF-36, particularly the BED group.

CONCLUSION

Our findings support the validity of the category of BED within a population of extremely obese individuals before undergoing GBP. BED subjects differed from their non-BED counterparts in that they had a greater disturbance in eating attitudes and behavior, a poorer physical and mental health status, and a suggestion of impaired hunger/satiety control. However, in this population of extremely obese subjects, the stability of BED warrants further study.

Traffic injury data, policy, and public health: lessons from Boston Chinatown

We note that long-standing land use and transportation policy are critical factors in creating traffic conditions and will have to play a role in reducing injuries. We present the historical progression of events that created current traffic conditions in Boston Chinatown and an analysis of traffic-related injuries at the community level for the years 1996-1998. Injuries were found to be as likely on weekends as on weekdays and frequently occurred late at night. Nighttime occupant injuries were found to be more likely on Friday, Saturday, and Sunday nights (relative risk = 2.26; confidence interval = 1.35-3.78, P =.0014). Injuries varied significantly by location for occupant (P = <.001) and for pedestrian injuries (P =.039). There were no peaks of injuries at traditionally defined commuter hours, which have been the standard time for assessing "worst case" traffic impacts by developers and government agencies. There was, however, a strong association between injuries and vehicle volume at 9 intersections with simple configurations for AM and PM commuter hours (R(2) = 0.589, P =.010), resulting in a calculated increase of 3-5 injuries per year for each increase of 1,000 vehicles. There was no such association at 10 intersections with complex configurations (R(2) = 0.104, P =.397). The 24-hour weekend patterns of vehicle volumes showed that traffic abated only between 3 and 7 AM, and the patterns appeared qualitatively to mirror the 24-hour pattern of injuries, suggesting that they were also indicative of injury risk. We suggest that there is a need for both long-term changes in policy and more immediate interventions. We also conclude that researchers should be cautious about assuming that traffic patterns conform to naive expectations such as rush hour peaks.

Cognitive therapy, nutritional therapy and their combination in the treatment of bulimia nervosa

BACKGROUND

This study compared the effectiveness of cognitive therapy (CT), nutritional therapy (NT), the combination of cognitive and nutritional therapy (CNT), against a control condition of support group (SG) in the treatment of bulimia nervosa.

METHODS

One hundred female out-patients who fulfilled DSM-III-R criteria for bulimia nervosa were randomized to the four treatment groups. NT and CT were designed to cover different areas with minimal overlap, and CNT provided all of the features of both of these treatments. The control condition was conducted in a group self-help format. Each of the treatments lasted 14 weeks.

RESULTS

All three active treatments as well as SG produced significant decreases in binge/vomit episodes. Intent-to-treat analysis found CNT and CT to be significantly more effective than SG in retaining subjects in treatment and completion of study, as well as in producing greater improvements in dysfunctional attitudes and self-control. CNT was superior to SG in achieving abstinence from bulimic behaviour. NT was superior to SG only in increase of self-control. Logistic regression found that the cognitive component, whether given alone or in conjunction with NT, and higher pre-treatment self-control scores were significant predictors for both completion of study and abstinence.

CONCLUSION

CT (either alone, or in combination with nutritional therapy) remains the treatment of choice for bulimia nervosa. A treatment escalation approach should be tested for the treatment of bulimia with the more intensive and less widely available CT (with or without nutritional counselling) offered after patients have failed the less intensive and more widely available support group treatment.

Short-term comparative outcomes associated with the use of GP IIb/IIIa antagonists in patients undergoing coronary intervention

BACKGROUND

Platelet glycoprotein (GP) IIb/IIIa antagonists reduce the occurrence of death, myocardial infarction (MI) and urgent revascularization among patients undergoing percutaneous coronary intervention (PCI). Despite a similar mechanism of platelet inhibition, the three currently approved agents vary widely in cost.

PURPOSE

The purpose of this prospectively designed, retrospective analysis was to determine clinical outcomes for patients receiving abciximab, tirofiban or eptifibatide as adjunctive therapy during PCI at a single center. We hypothesized that there would be no difference in outcomes during hospitalization following PCI in patients receiving tirofiban or eptifibatide compared with those patients who received abciximab. Outcomes examined included in-hospital mortality, hemorrhagic procedural complications, need for recatheterization, peak creatine kinase following intervention and length of hospital stay (LOS).

RESULTS

Two hundred and sixty seven consecutive patients in whom GP IIb/IIIa antagonist therapy was initiated in the catheterization laboratory for PCI were analyzed. Abciximab-treated patients were more likely to be undergoing primary (p<0.001) and rescue (p=0.022) PCI and to have received fibrinolytic therapy (p=0.013) when compared to patients receiving tirofiban or eptifibatide. There were no significant differences between abciximab- and non abciximab-treated patients in either the primary PCI or non primary PCI groups in any of the studied endpoints. In patients undergoing primary PCI, abciximab-treated patients when compared with non abciximab-treated patients exhibited a trend toward an increase in hospital LOS (7.8+/-7.0 d vs 6.2+/-3.9, p=0.19) and in the frequency of hemorrhagic complications (22.1% vs 5.3%, p=0.11). In patients not receiving fibrinolytic therapy, abciximab-treated patients experienced a trend toward increased hemorrhagic complications following PCI when compared to non abciximab-treated patients (10.2% vs 6.0%, p=0.28). Complications distant from the vascular access site comprised 62.5% of hemorrhagic complications in the abciximab-treated group, but only 20% of the complications in the non-abciximab treated population (p<0.001). These data suggest no differences in acute outcomes between groups of patients receiving abciximab or other approved GP IIb/IIIa antagonists highlighting a potential significant cost saving. These data will require interpretation following the publication of comparative trials.

Retrospective study of orthovoltage radiation therapy for nasal tumors in 42 dogs

Megavoltage radiation therapy currently is the standard of care for dogs with nasal tumors. Some studies report that surgery and adjunctive orthovoltage radiation therapy result in longer control of these tumors than does megavoltage radiation therapy alone. This study reports less effective control of nasal tumors in dogs treated with surgery and orthovoltage radiation than previously observed, supporting the superiority of megavoltage radiation therapy for these tumors. In addition, this study suggests 2 new prognostic indicators for dogs with nasal tumors and describes toxicity associated with surgery and orthovoltage therapy. Forty-two dogs with nasal tumors were treated with surgical cytoreduction and 48 Gy orthovoltage radiation therapy administered in twelve 4-Gy fractions. Median survival was 7.4 months. One- and 2-year survival rates were 37% and 17%, respectively. Dogs with facial deformity had shorter survival than those without deformity (P = .005). Dogs with resolution of clinical signs after treatment had longer survival than those with chronic nasal signs (P = .0001). Acute radiation toxicity was moderate to severe for skin and eye and negligible for oral mucosa. Toxicity healed within 1 month after radiation therapy. Late toxicity was mild, but 70% of evaluable dogs experienced persistent ocular signs. Only 39% of dogs achieved a disease-free period.

Treatment of immune-mediated hemolytic anemia in dogs with cyclophosphamide

A review of 60 cases of immune-mediated hemolytic anemia (IMHA) in the dog was performed in order to characterize the disease and to identify potential prognostic indicators. Dogs ranged in age from 1 to 13 years, with a mean age of 6.5 years. The 2 most commonly affected breeds were Cocker Spaniels and Labrador Retrievers. Fifty-two of the 60 dogs tested (87%) were autoagglutination positive and spherocytes were present in 45 (75%). Forty-one (89%) of 46 patients tested positive for the presence of immunoglobulin on the red blood cell surface (Coombs assay). The most common clinical signs at presentation were lethargy, weakness, pale mucous membranes, icterus, hemoglobinuria, and anorexia. PCV less than 25% was present in 59 (98%) dogs. At the time of presentation, 35 dogs (58%) had a nonregenerative anemia, whereas 25 patients (42%) had a regenerative response. Thrombocytopenia was seen in 41 (68%) dogs. Nine of 34 dogs (26%) had a prolonged prothrombin time, 19 of 34 (56%) had a prolonged activated partial thromboplastin clotting time, and 12 of 34 (35%) had abnormal fibrinogen concentrations. All dogs received prednisone at immunosuppressive doses (2.2-4.4 mg/kg PO as a single or divided dose every 24 hours) and cyclophosphamide as primary therapy. Forty-one dogs (63%) received cyclophosphamide at 50 mg/m2 q24h for 4 days, whereas 9 dogs (15%) received an initial high dose (200 mg/m2) followed by 3 days of a lower dose (50 mg/m2 q24h). No statistical difference in survival times was found for either protocol. Thirteen dogs were treated with azathioprine in addition to cyclophosphamide and prednisone. The median survival time of dogs that received all 3 drugs was 370 days as compared to 9 days for those dogs that were treated with cyclophosphamide and prednisone alone. Thirty-one (52%) dogs died from the disease, 13 (22%) dogs were alive, and 15 (25%) dogs were lost to follow-up. The median length of survival for all dogs was 21 days. Eight dogs that were discharged from the hospital suffered a relapse (PCV < 25%).

Concentrations of substance P and prostaglandin E2 in synovial fluid of normal and abnormal joints of horses

OBJECTIVE

To correlate substance P content of synovial fluid with prostaglandin E2 content, radiographic evidence of joint abnormality, and anatomic location of the joint for normal and osteoarthritic joints of horses.

SAMPLE POPULATION

Synovial fluid from 46 normal joints in 21 horses and 16 osteoarthritic joints in 10 horses.

PROCEDURE

Normal and osteoarthritic joints were identified by clinical and radiographic examination, by response to nerve blocks, during scintigraphy or surgery, or by clinicopathologic evaluation. Substance P and prostaglandin E2 contents of synovial fluid were determined by radioimmunoassay. Radio-graphs of joints were assigned a numeric score reflecting severity of lesions. Joints were assigned a numeric score reflecting anatomic location.

RESULTS

Median concentrations of substance P and prostaglandin E2 were significantly increased in osteoarthritic joints, compared with normal joints. A significant correlation was found between concentrations of substance P and prostaglandin E2 in synovial fluid, but a correlation was not detected between substance P concentration in synovial fluid and anatomic location of the joint or between radiographic scores of osteoarthritic joints and concentrations of substance P or prostaglandin E2.

CONCLUSIONS AND CLINICAL RELEVANCE

A correlation existed between concentrations of substance P and prostaglandin E2 in synovial fluid obtained from normal and osteoarthritic joints. However, content of substance P in synovial fluid cannot be predicted by the radiographic appearance of the joint or its anatomic location. Substance P and prostaglandin E2 may share an important and related role in the etiopathogenesis of osteoarthritis, lending credence to the importance of neurogenic inflammation in horses.

Effects of losartan and captopril on left ventricular volumes in elderly patients with heart failure: results of the ELITE ventricular function substudy

BACKGROUND

The mechanism by which angiotensin-converting enzyme inhibitors reduce mortality rates and disease progression in patients with heart failure is likely mediated in part through prevention of adverse ventricular remodeling. This study examined the effects of the angiotensin-converting enzyme inhibitor captopril and the angiotensin II type 1 receptor antagonist losartan on ventricular volumes and function in elderly patients with heart failure and reduced left ventricular ejection fraction (< or =40%).

METHODS

Patients underwent radionuclide ventriculograms (RVG) at baseline and were randomized to either captopril (n = 16) or losartan (n = 13). After 48 weeks, another RVG was obtained. Therapy was then withdrawn for at least 5 days, and the RVG was repeated while the patient was not receiving the drug.

RESULTS

At 48 weeks both captopril and losartan significantly reduced left ventricular (LV) end-diastolic volume index (135 +/- 26 to 128 +/- 23 mL/m(2) for losartan, P <.05 vs baseline; 142 +/- 25 to 131 +/- 20 mL/m(2) for captopril, P <.01; mean (SD). Captopril also reduced LV end-systolic volume index (98 +/- 24 to 89 +/- 21 mL/m(2), P <.01 vs. baseline), whereas a nonsignificant trend was observed for the losartan group (97 +/- 23 to 90 +/- 16 mL/m(2), P = not significant). The between-group differences in the changes in LV volumes were not statistically significant. After drug withdrawal, LV end-diastolic volume index remained significantly lower than baseline in the captopril group (P <.01).

CONCLUSIONS

Both captopril and losartan prevent LV dilation, representing adverse ventricular remodeling, previously seen with placebo treatment. Reverse remodeling was observed in the captopril group. On the basis of these results, the relative effects on LV remodeling do not provide a rationale for a survival benefit of losartan over captopril.

Central nervous system manifestations of childhood shigellosis: prevalence, risk factors, and outcome

BACKGROUND AND OBJECTIVE

Alterations in consciousness, including seizures, delirium, and coma, are known to occur during Shigella infection. Previous reports have suggested that febrile convulsions and altered consciousness are more common during shigellosis than with other childhood infections. Those reports, however, have been from locations where S dysenteriae type 1 was not common, thus making it difficult to assess the specific contribution that S dysenteriae type 1 infection, and Shiga toxin, might make to the pathogenesis of altered consciousness in children with shigellosis. In this study we seek to determine the prevalence, risk factors, and outcome of altered consciousness in children with shigellosis in Bangladesh, a country where infection with all four species of Shigella is common. We particularly focus on the importance of metabolic abnormalities, which we have previously shown to be a common feature of shigellosis in this population.

METHODS

This study was conducted at the Diarrhea Treatment Centre of the International Centre for Diarrhoeal Disease Research, Bangladesh in Dhaka, Bangladesh, which provides care free of charge to persons with diarrhea. During 1 year, a study physician identified all inpatients infected with Shigella by checking the logs of the Clinical Microbiology Laboratory daily. Study physicians obtained demographic and historical information by reviewing the patient charts and by interviewing patients, or their parents or guardians, to confirm or complete the history of illness obtained on admission. Patients were categorized as being conscious or unconscious based on a clinical scale; having a seizure documented in the hospital; or having a seizure by history during the current illness that was not witnessed by medical personnel. Patient outcome was classified as discharged improved, discharged against medical advice, transferred to another health facility, or died in the Treatment Centre. Laboratory examinations were ordered at the discretion of the attending physician; all such information was recorded on the study form. Clinical management was by the attending physician. Factors independently predictive of a documented seizure, or of unconsciousness, were determined using a multiple logistic regression analysis. For this analysis variables associated with unconsciousness or a documented seizure in the analysis of variance or chi2 analyses were entered into the regression equation and eliminated in a backward stepwise fashion if the probability associated with the likelihood ratio statistic exceeded .10.

RESULTS

During this 1-year study, 83 402 persons with diarrhea came to the Treatment Centre for care, and 6290 patients were admitted to the inpatient unit. Shigella was isolated from a stool or rectal swab sample of 863 (13.7%) of the inpatients. Seventy-one (8%) of the inpatients with shigellosis were >/=15 years old; 61 (86%) were conscious; 10 (14%) were unconscious; none had either a documented seizure or a seizure by history during this illness. Seven hundred ninety-two patients were <15 years old (92%); 654 (83%) were conscious; 73 (9%) were unconscious; 41 (5%) had a documented seizure (compared with >/=15-year age group); 24 (3%) had a seizure by history during this illness. Of the 41 patients with documented seizures, 19 (46.3%) had a seizure at the time of admission, and 22 (53.7%) had a seizure after admission. Twenty-five (61.0%) of the 41 patients with documented seizures were reported to have a seizure during this illness before coming to the Treatment Centre. Clinical features that are known to cause altered consciousness-fever, severe dehydration, hypoglycemia, hyponatremia, or meningitis-were present in 38 (92.7%) of the 41 patients in whom a seizure was witnessed and in 67 (91.8%) of the 73 patients who were unconscious. Nineteen (46. 3%) of the patients who had a seizure documented had two of these five features, 4 (9.8%) had three, and 1 (2. (ABSTRACT TRUNCATED)

A two-part phase I trial of high-dose interleukin 2 in combination with soluble (Chinese hamster ovary) interleukin 1 receptor

Our purpose was to determine the maximum tolerated dose and toxicity associated with soluble Chinese hamster ovary [s(CHO)] recombinant human interleukin (IL) 1 receptor (IL-1R; Immunex, Seattle, WA) administration in humans and to determine the effective biological dose and/or maximum tolerated dose of the s(CHO) IL-1R in combination with high-dose IL-2 as determined by reduction in IL-2 toxicity and modulation of its biological effects. Twenty-seven patients with metastatic cancer were treated with escalating doses of s(CHO) IL-1R at 1, 1, 5, 10, 20, 40, and 55 mg/m2 i.v. on days -6 (except cohort 2), 1, and 15 and IL-2 at doses of 300,000 IU/kg (cohort 1) and 600,000 IU/kg (cohorts 2-7) i.v. every 8 h on days 1-5 and 15-19. No toxicity directly attributable to s(CHO) IL-1R was observed. The median number of IL-2 doses was 23. Hypotension and neurotoxicity were the major dose-limiting toxicities for the IL-2/s(CHO) IL-1R combination. Of the 24 patients treated with full-dose IL-2, there were six responses, three complete and three partial (response rate, 25%). Three patients developed thyroid dysfunction, and all 3 responding melanoma patients exhibited vitiligo. The t1/2 of s(CHO) IL-1R alone was 24-30 h and was not significantly altered by coadministration with IL-2. Whole-blood functional assays indicated that sufficient s(CHO) IL-1R was present in the circulation at top dose levels to inhibit the in vitro effects of IL-1beta on IL-8 induction; however, no effect on IL-2-induced IL-8 induction, or on the IL-1beta- or IL-2-induced tumor necrosis factor production, was observed. Suppression of IL-2-mediated tumor necrosis factor alpha and IL-6 induction in vivo during the first 24 h after IL-2 administration was observed, and the neutrophil chemotactic defect normally seen with IL-2 was not observed. IL-1R antagonist induction far exceeded that seen previously with IL-2 alone. No inhibition of either serum C-reactive protein induction or enhanced urinary nitrate excretion and no consistent effect on IL-2-related changes in peripheral blood mononuclear cell phenotype or endothelial adhesion molecule expression were seen. The coadministration of s(CHO) IL-1R produced no apparent reduction in IL-2 clinical toxicity manifested by either the ability to administer more IL-2 than anticipated or a reduction in the toxicity associated with a given amount of IL-2. Therefore, no effective biological dose could be identified for the s(CHO) IL-1R.

Nonsurgical factors that influence the outcome of bariatric surgery: a review

OBJECTIVE

Severe obesity (ie, at least 100% overweight or body mass index > or =40 kg/m2) is associated with significant morbidity and increased mortality. It is apparently becoming more common in this country. Conventional weight-loss treatments are usually ineffective for severe obesity and bariatric surgery is recommended as a treatment option. However, longitudinal data on the long-term outcome of bariatric surgery are sparse. Available data indicate that the outcome of bariatric surgery, although usually favorable in the short term, is variable and weight regain sometimes occurs at 2 years after surgery. The objective of this study is to present a review of the outcome of bariatric surgery in three areas: weight loss and improvement in health status, changes in eating behavior, and psychosocial adjustment. The study will also review how eating behavior, energy metabolism, and psychosocial functioning may affect the outcome of bariatric surgery. Suggestions for additional research in these areas are made.

METHOD

Literature review.

RESULTS

On average, most patients lose 60% of excess weight after gastric bypass and 40% after vertical banded gastroplasty. In about 30% of patients, weight regain occurs at 18 months to 2 years after surgery. Binge eating behavior, which is common among the morbidly obese, may recur after surgery and is associated with weight regain. Energy metabolism may affect the outcome of bariatric surgery, but it has not been systematically studied in this population. Presurgery psychosocial functioning does not seem to affect the outcome of surgery, and psychosocial outcome is generally encouraging over the short term, but there are reports of poor adjustment after weight loss, including alcohol abuse and suicide.

CONCLUSIONS

Factors leading to poor outcome of bariatric surgery, such as binge eating and lowered energy metabolism, should be studied to improve patient selection and outcome. Long-term outcome data on psychosocial functioning are lacking. Longitudinal studies to examine the long-term outcome of bariatric surgery and the prognostic indicators are needed.

Preliminary outcomes following cryosurgical ablation of the prostate in patients with clinically localized prostate carcinoma

PURPOSE

Cryosurgical ablation of the prostate is a novel therapeutic modality that induces cell lysis in the prostate by direct application of low temperatures. We have been conducting an ongoing prospective pilot study of the use of cryosurgical prostate ablation in treating patients with nonmetastatic prostate adenocarcinoma since January 1993. Results in 145 consecutive patients with mean 36 months and minimum 12 months of followup are presented.

MATERIALS AND METHODS

Accrual was open to patients with clinical stages T1a to T3c prostate adenocarcinoma. Pelvic lymph node dissections were recommended but not required for patients with prostate specific antigen (PSA) greater than 15 ng./ml. before study entry. PSA changes, random prostate biopsy findings and morbidities after cryosurgical prostate ablation were recorded for each patient.

RESULTS

Overall actuarial rates at 42 months for maintaining PSA less than 0.3 and less than 1.0 were 59% and 66%, respectively. The overall actuarial progression-free rate at 60 months was 56%. Among 160 biopsies performed 16% showed some evidence of residual carcinoma. Overall crude rates of maintaining either a negative biopsy or PSA less than 0.3 at 6 and 24 months after cryosurgical prostate ablation were 87% and 73%, respectively. Significantly higher morbidities were seen in previously radiated patients undergoing cryosurgical prostate ablation compared to those with no prior radiation. Among nonradiated patients 85% experienced no significant morbidity after cryosurgical prostate ablation.

CONCLUSIONS

Although preliminary, short-term outcomes after cryosurgical prostate ablation appear to be comparable to identical outcomes reported for external beam radiotherapy. Based on these results cryosurgical prostate ablation appears to be an effective therapeutic alternative for treating patients with localized prostate adenocarcinoma.

Increased serum total creatine kinase and creatine kinase isoenzyme MB after cryosurgical ablation of the prostate

PURPOSE

Several reports have documented that the MB isoenzyme of creatine kinase is present in prostatic tissue. However, since it has been shown that lower urinary tract manipulations, including transurethral prostatectomy, do not significantly increase serum creatine kinase isoenzyme MB levels, such elevations, which are found in patients after prostatic surgery, are believed to be specific for myocardial infarction. We examined whether cryosurgical ablation of the prostate altered serum creatine kinase or isoenzyme MB levels.

MATERIALS AND METHODS

In 81 consecutive patients undergoing routine cryosurgical ablation of the prostate serum levels of creatine kinase and creatine kinase isoenzyme MB were measured from peripheral blood specimens drawn preoperatively, in the recovery room and at 8 and 24 hours postoperatively. Postoperative electrocardiograms were compared to the preoperative study.

RESULTS

In 72 of 81 patients (89%) significant elevations in creatine kinase and creatine kinase isoenzyme MB levels were noted at all time points after cryosurgical ablation of the prostate and appeared to reach a peak at 16 hours postoperatively. The mean increases within the first 8 hours after cryosurgical ablation of the prostate were 1,355 units per 1. for creatine kinase and 46.6 ng./ml. for creatine kinase isoenzyme MB. No patient had any significant changes on the postoperative electrocardiogram. All 9 patients (11%) who did not have significant creatine kinase or creatine kinase isoenzyme MB levels after cryosurgery had undergone prior cryosurgery or combined radiation and hormonal therapy.

CONCLUSIONS

Cryosurgical ablation of the prostate appears to produce elevations in serum creatine kinase and creatine kinase isoenzyme MB, which are specific to the procedure. Assays for creatine kinase isoenzyme MB are unreliable to render a diagnosis of myocardial infarction after cryosurgical ablation of the prostate.

Orbital color Doppler imaging in carotid occlusive disease

OBJECTIVE

To define orbital circulation abnormalities identified by color Doppler imaging in patients with severe carotid occlusive disease.

PATIENTS

Twenty-four patients referred to a hospital-based neuro-ophthalmology service with hemodynamically significant carotid occlusive disease (> 75% stenosis) were prospectively studied. Eight had signs of ocular ischemic syndrome; 12 of the 24 patients underwent endarterectomy.

MAIN OUTCOME MEASURES

Peak systolic velocity of the central retinal, posterior ciliary, and ophthalmic artery and pulsatility indexes as determined by color Doppler imaging.

METHODS

Color Doppler imaging was performed using a 7.5-MHz probe. Both eyes were studied in all patients and carotid duplex imaging was obtained.

RESULTS

All patients with hemodynamically significant carotid occlusive disease had lower mean peak systolic velocities in the central retinal, posterior ciliary, and ophthalmic arteries and higher pulsatility indexes compared with normal control patients. Endarterectomy improved peak systolic velocities. Reversal of ophthalmic flow direction as a separate variable was unassociated with altered mean central retinal or posterior ciliary artery flow velocities. Patients with ocular ischemic syndrome may have similar orbital color Doppler imaging findings compared with patients with severe carotid occlusive disease without overt manifestations of chronic ocular ischemia.

CONCLUSION

Orbital circulation is highly adaptable even when faced with severe compromise in proximal blood flow.

Randomized placebo-controlled clinical trial of high-dose interleukin-2 in combination with a soluble p75 tumor necrosis factor receptor immunoglobulin G chimera in patients with advanced melanoma and renal cell carcinoma

PURPOSE

A randomized, double-blind, placebo-controlled trial was performed to compare the toxicity and biologic effects of treatment with high-dose intravenous (IV) bolus interleukin-2 (IL-2) plus the recombinant human soluble p75 tumor necrosis factor (TNF) receptor immunoglobulin G (IgG) chimera (rhuTNFR:Fc) with high-dose IL-2 alone in patients with advanced melanoma and renal cell carcinoma.

PATIENTS AND METHODS

Twenty patients with advanced melanoma or renal cell carcinoma were randomized to receive IL-2 (Chiron, Emeryville, CA) 600,000 IU/kg every 8 hours on days 1 to 5 and 15 to 19 (maximum, 28 doses) combined with placebo or the rhuTNFR:Fc fusion protein (Immunex, Seattle, WA) 10 mg/m2 on days 1 and 15 and 5 mg/m2 on days 3, 5, 17, and 19. The impact of rhuTNFR:Fc on IL-2 toxicity and biologic effects was evaluated.

RESULTS

No clinically significant difference in toxicity was observed in the two treatment arms. The adjusted median number of IL-2 doses administered during cycle 1 was 24.5 (range, seven to 28) and 21.5 (range, five to 27) for the placebo and rhuTNFR:Fc arms, respectively (P = .544). IL-2-induced TNF bioactivity, neutrophil chemotactic defect, and serum IL-6, IL-8, and IL-1 receptor antagonist (IL-1RA) induction were suppressed by rhuTNFR:Fc. Two of nine assessable patients (22%) on IL-2/placebo and three of 10 patients (30%) on IL-2/rhuTNFR:Fc responded.

CONCLUSION

Despite evidence of in vitro neutralization of TNF functional activity and partial inhibition of other secondary biologic effects of IL-2, rhuTNFR:Fc does not reduce the clinical toxicity associated with high-dose IL-2 therapy. These results suggest that the toxicity and antitumor effects of IL-2 treatment are independent of circulating TNF.