A myeloid program associated with COVID-19 severity is decreased by therapeutic blockade of IL-6 signaling

Altered myeloid inflammation and lymphopenia are hallmarks of severe infections. We identified the upregulated EN-RAGE gene program in airway and blood myeloid cells from patients with acute lung injury from SARS-CoV-2 or other causes across 7 cohorts. This program was associated with greater clinical severity and predicted future mechanical ventilation and death. EN-RAGEhi myeloid cells express features consistent with suppressor cell functionality, including low HLA-DR and high PD-L1. Sustained EN-RAGE program expression in airway and blood myeloid cells correlated with clinical severity and increasing expression of T cell dysfunction markers. IL-6 upregulated many EN-RAGE program genes in monocytes in vitro. IL-6 signaling blockade by tocilizumab in a placebo-controlled clinical trial led to rapid normalization of EN-RAGE and T cell gene expression. This identifies IL-6 as a key driver of myeloid dysregulation associated with worse clinical outcomes in COVID-19 patients and provides insights into shared pathophysiological mechanisms in non-COVID-19 ARDS.

First-in-human phase 1 trial evaluating safety, pharmacokinetics, and pharmacodynamics of NLRP3 inflammasome inhibitor, GDC-2394, in healthy volunteers

Inappropriate and chronic activation of the cytosolic NOD-, LRR-, and pyrin domain-containing 3 (NLRP3) inflammasome, a key component of innate immunity, likely underlies several inflammatory diseases, including coronary artery disease. This first-in-human phase I trial evaluated safety, pharmacokinetics (PKs), and pharmacodynamics (PDs) of oral, single (150-1800 mg) and multiple (300 or 900 mg twice daily for 7 days) ascending doses (SADs and MADs) of GDC-2394, a small-molecule inhibitor of NLRP3, versus placebo in healthy volunteers. The study also assessed the food effect on GDC-2394 and its CYP3A4 induction potential in food-effect (FE) and drug-drug interaction (DDI) stages, respectively. Although GDC-2394 was adequately tolerated in the SAD, MAD, and FE cohorts, two participants in the DDI stage experienced grade 4 drug-induced liver injury (DILI) deemed related to treatment, but unrelated to a PK drug interaction, leading to halting of the trial. Both participants experiencing severe DILI recovered within 3 months. Oral GDC-2394 was rapidly absorbed; exposure increased in an approximately dose-proportional manner with low-to-moderate intersubject variability. The mean terminal half-life ranged from 4.1 to 8.6 h. Minimal accumulation was observed with multiple dosing. A high-fat meal led to delays in time to maximum concentration and minor decreases in total exposure and maximum plasma concentration. GDC-2394 had minimal CYP3A4 induction potential with the sensitive CYP3A4 substrate, midazolam. Exploratory ex vivo whole-blood stimulation assays showed rapid, reversible, and near-complete inhibition of the selected PD biomarkers, IL-1β and IL-18, across all tested doses. Despite favorable PK and target engagement PD, the GDC-2394 safety profile precludes its further development.

Myeloid cell influx into the colonic epithelium is associated with disease severity and non-response to anti-Tumor Necrosis Factor Therapy in patients with Ulcerative Colitis

Ulcerative colitis (UC) is an idiopathic chronic inflammatory disease of the colon with sharply rising global prevalence. Dysfunctional epithelial compartment (EC) dynamics are implicated in UC pathogenesis although EC-specific studies are sparse. Applying orthogonal high-dimensional EC profiling to a Primary Cohort (PC; n=222), we detail major epithelial and immune cell perturbations in active UC. Prominently, reduced frequencies of mature BEST4+OTOP2+ absorptive and BEST2+WFDC2+ secretory epithelial enterocytes were associated with the replacement of homeostatic, resident TRDC+KLRD1+HOPX+ γδ+ T cells with RORA+CCL20+S100A4+ TH17 cells and the influx of inflammatory myeloid cells. The EC transcriptome (exemplified by S100A8, HIF1A, TREM1, CXCR1) correlated with clinical, endoscopic, and histological severity of UC in an independent validation cohort (n=649). Furthermore, therapeutic relevance of the observed cellular and transcriptomic changes was investigated in 3 additional published UC cohorts (n=23, 48 and 204 respectively) to reveal that non-response to anti-Tumor Necrosis Factor (anti-TNF) therapy was associated with EC related myeloid cell perturbations. Altogether, these data provide high resolution mapping of the EC to facilitate therapeutic decision-making and personalization of therapy in patients with UC.

Prolonged cycling lowers subsequent running mechanical efficiency in collegiate triathletes

Background

A significant challenge that non-elite collegiate triathletes encounter during competition is the decline in running performance immediately after cycling. Therefore, the purpose of this study was to determine if performing a 40-km bout of cycling immediately before running would negatively influence running economy and mechanical efficiency of running during simulated race conditions in collegiate triathletes.

Methods

Eight competitive club-level collegiate triathletes randomly performed two trials: cycling for 40 km (Cycle-Run) or running for 5 km (Run–Run), immediately followed by a four-minute running economy and mechanical efficiency of running test at race pace on an instrumented treadmill. Blood lactate, respiratory exchange ratio, mechanical work, energy expenditure, and muscle glycogen were also measured during the four-minute running test.

Results

Mechanical efficiency of running, but not running economy, was significantly lower in Cycle-Run, compared to Run–Run (42.1 ± 2.5% vs. 48.1 ± 2.5%, respectively; p = 0.027). Anaerobic energy expenditure was significantly higher in the Cycle-Run trial, compared to the Run–Run trial (16.3 ± 2.4 vs. 7.6 ± 1.1 kJ; p = 0.004); while net (151.0 ± 12.3 vs. 136.6 ± 9.6 kJ; p = 0.204) and aerobic energy expenditure (134.7 ± 12.3 vs. 129.1 ± 10.5 kJ; p = 0.549) were not statistically different between trials. Analysis of blood lactate, respiratory exchange ratio, mechanical work, and changes in muscle glycogen revealed no statistically significant differences between trials.

Conclusions

These results suggest that mechanical efficiency of running, but not running economy, is decreased and anaerobic energy expenditure is increased when a 40-km bout of cycling is performed immediately before running in collegiate triathletes.

Surfactant protein D is a biomarker of influenza-related pediatric lung injury

BACKGROUND

Biomarkers that can risk-stratify children with influenza virus lower respiratory infection may identify patients for targeted intervention. Early elevation of alveolar-related proteins in the bloodstream in these patients could indicate more severe lung damage portending worse outcomes.

METHODS

We used a mouse model of human influenza infection and evaluated relationships between lung pathophysiology and surfactant protein D (SP-D), SP-A, and Club cell protein 16 (CC16). We then measured SP-A, SP-D, and CC16 levels in plasma samples from 94 children with influenza-associated acute respiratory failure (PICFLU cohort), excluding children with underlying conditions explaining disease severity. We tested for associations between levels of circulating proteins and disease severity including the diagnosis of acute respiratory distress syndrome (ARDS), mechanical ventilator, intensive care unit and hospital days, and hospital mortality.

RESULTS

Circulating SP-D showed a greater increase than SP-A and CC16 in mice with increased alveolar-vascular permeability following influenza infection. In the PICFLU cohort, SP-D was associated with moderate-severe ARDS diagnosis (p = 0.01) and with mechanical ventilator (r = 0.45, p = 0.002), ICU (r = 0.44, p = 0.002), and hospital days (r = 0.37, p = 0.001) in influenza-infected children without bacterial coinfection. Levels of SP-D were lower in children with secondary bacterial pneumonia (p = 0.01) and not associated with outcomes. CC16 and SP-A levels did not differ with bacterial coinfection and were not consistently associated with severe outcomes.

CONCLUSIONS

SP-D has potential as an early circulating biomarker reflecting a degree of lung damage caused directly by influenza virus infection in children. Secondary bacterial pneumonia alters SP-D biomarker performance.

A Phase 2 Randomized, Double-Blind, Placebo-Controlled Trial of the Monoclonal Antibody MHAA4549A in Patients With Acute Uncomplicated Influenza A Infection

Background

MHAA4549A, a human monoclonal antibody targeting the influenza A hemagglutinin stalk, neutralizes influenza A virus in animal and human volunteer challenge studies. We investigated the safety and tolerability, efficacy, and pharmacokinetics of MHAA4549A in outpatients with acute, uncomplicated influenza A infection.

Methods

This was a phase 2, randomized, double-blind, placebo-controlled trial of single intravenous (IV) doses of 3600 mg or 8400 mg of MHAA4549A or IV placebo in adult outpatients testing positive for influenza A. Patients were enrolled across 35 sites in 6 countries. Randomization and dosing occurred within ≤72 hours of symptom onset; the study duration was 14 weeks. The primary end point was the nature and frequency of adverse events (AEs). Secondary end points included median time to alleviation of all influenza symptoms, effects on nasopharyngeal viral load and duration of viral shedding, and MHAA4549A serum pharmacokinetics.

Results

Of 125 randomized patients, 124 received study treatment, with 99 confirmed positive for influenza A by central testing. The frequency of AEs between the MHAA4549A and placebo groups was similar; nausea was most common (8 patients; 6.5%). MHAA4549A serum exposure was confirmed in all MHAA4549A-treated patients and was dose-proportional. No hospitalizations or deaths occurred. Between the MHAA4549A and placebo groups, no statistically significant differences occurred in the median time to alleviation of all symptoms, nasopharyngeal viral load, or duration of viral shedding.

Conclusions

While MHAA4549A was safe and well tolerated with confirmed exposure, the antibody did not improve clinical outcomes in patients with acute uncomplicated influenza A infection.

Pharmacokinetics of the Monoclonal Antibody MHAA4549A Administered in Combination With Oseltamivir in Patients Hospitalized With Severe Influenza A Infection

MHAA4549A is a human anti‐influenza A monoclonal antibody developed to treat influenza A. We report MHAA4549A serum, nasopharyngeal, and tracheal aspirate pharmacokinetics from a phase 2b study in hospitalized patients with severe influenza A. Patients were randomized 1:1:1 into 3 groups receiving single intravenous doses of 3600 mg (n = 55) or 8400 mg (n = 47) MHAA4549A or placebo (n = 56). Patients also received oral oseltamivir twice daily for ≥5 days. Serum, nasopharyngeal, and tracheal aspirate pharmacokinetic samples were collected on days 1‐60 from MHAA4549A‐treated groups. Day 5 plasma samples from all groups were collected for assessing the pharmacokinetics of oseltamivir and its active metabolite, oseltamivir carboxylate. Noncompartmental pharmacokinetic analysis was performed using Phoenix WinNonlin. Data were collected during a preplanned interim analysis that became final when the trial terminated because of a lack of efficacy. Serum MHAA4549A concentrations were dose‐proportional and biphasic. Mean MHAA4549A clearance was 288‐350 mL/day, and mean half‐life was 17.8‐19.0 days. Nasopharyngeal MHAA4549A concentrations were non‐dose‐proportional. We detected MHAA4549A in tracheal aspirate samples, but intersubject variability was high. MHAA4549A serum and nasopharyngeal exposures were confirmed in all MHAA4549A‐treated patients. Serum MHAA4549A had faster clearance and a shorter half‐life in influenza A‐infected patients compared with healthy subjects. MHAA4549A detection in tracheal aspirate samples indicated exposure in the lower respiratory tract. Oseltamivir and oseltamivir carboxylate exposures were similar between MHAA4549A‐treated and placebo groups, suggesting a lack of MHAA4549A interference with oseltamivir pharmacokinetics.

In Vivo Assessment of Antibody-Dependent Enhancement of Influenza B Infection

A theoretical safety concern proposed in the influenza literature is that therapeutic antiviral antibodies could have the potential for antibody-dependent enhancement (ADE) of infection and disease. ADE may occur when virus-specific antibodies at subtherapeutic, nonneutralizing concentrations facilitate virus uptake and, in some cases, enhance replication, which can lead to an exacerbation of virus-mediated disease. Alternatively, ADE may occur due to antibody-dependent complement activation exacerbating virus-mediated disease in the absence of increased replication. As a result of this theoretical safety concern, safety assessment of anti-influenza antibodies may include an in vivo evaluation of ADE of infection and/or disease. These studies were conducted to investigate the potential of MHAB5553A, a broadly specific, neutralizing therapeutic anti-influenza B antibody, to elicit ADE of infection and disease in mouse models of influenza B infection. In parallel studies, female DBA/2J mice were infected with either influenza B/Victoria/504/2000 or influenza B/Brisbane/60/2008 representing distinct lineages. Assessment of ADE was based on an integration of results from multiple endpoints, including infectious lung viral titers and genomes, body weight, mortality, lung weight, and histopathology. In these studies, the high dose of 15 mg/kg MHAB5553A resulted in substantial attenuation of influenza pneumonia, with more modest effects at 1.5 mg/kg; whereas MHAB5553A treatment at 0.15 or 0.015 mg/kg was generally comparable to vehicle-treated controls. Our results demonstrate that MHAB5553A across a broad range of doses did not enhance primary influenza B infection or disease in this model, and represent a nonclinical de-risking of the ADE potential with this antibody.

Early Amplified Respiratory Bioactive Lipid Response Is Associated With Worse Outcomes in Pediatric Influenza-Related Respiratory Failure

Background

Biomarkers are needed for early identification of patients at risk of severe complications from influenza infection, including prolonged respiratory failure and death. Eicosanoids are bioactive lipid mediators with pro- and anti-inflammatory properties produced in response to infection. This study assessed the relationships between the host bioactive lipid response, influenza viral load, and clinical outcomes.

Methods

Influenza-positive, intubated children ≤18 years old were enrolled across 26 US pediatric intensive care units (PICUs). Mass spectrometry was used to measure >100 lipid metabolites in endotracheal and nasopharyngeal samples. Influenza viral load was measured by quantitative polymerase chain reaction.

Results

Age and bacterial co-infection were associated with multiple bioactive lipids (P < .05). Influenza viral load was lower in patients with bacterial co-infection compared with those without, and pro-inflammatory bioactive lipids positively correlated with viral load in bacterially co-infected children (P < .05). Lipids associated with disease resolution correlated with viral load in patients without bacterial co-infection (P < .01). After adjusting for age and bacterial co-infection status, elevated pro- and anti-inflammatory lipids measured early in the intensive care unit course were associated with higher mortality, whereas influenza viral load and endotracheal cytokine levels were not associated with clinical outcomes. Prostaglandin E₂, arachidonic acid, docosahexaenoic acid, and 12-hydroxyeicosatetraenoic acid measured within 72 hours of PICU admission predicted death or prolonged (≥28 days) mechanical ventilator support (area under the curve, 0.72-0.79; P < .02) not explained by admission illness severity.

Conclusions

Children with influenza-related complications have early bioactive lipid responses that may reflect lung disease severity. Respiratory bioactive lipids are candidate prognostic biomarkers to identify children with the most severe clinical outcomes.

Correlation of Cytomegalovirus (CMV) Disease Severity and Mortality With CMV Viral Burden in CMV-Seropositive Donor and CMV-Seronegative Solid Organ Transplant Recipients

Background

The rate of cytomegalovirus (CMV) viral load increase and peak viral loads are associated with CMV disease in kidney and liver transplant recipients, but relationships to disease severity or mortality have not been shown.

Methods

Using stored serial serum specimens from renal (n = 59) and liver (n = 35) transplant recipients (D+R-; CMV-seropositive donors, CMV-seronegative recipients) from 2 prospective, randomized, controlled, interventional prophylaxis trials of CMV immune globulin (CMVIG), CMV viral load was measured using the COBAS quantitative polymerase chain reaction assay and the World Health Organization CMV standard. Patients with severe CMV-associated disease were classified according to trial definitions. Pairwise comparisons of mean viral load among deceased, surviving diseased, and nondiseased patients were analyzed by 2-way analysis of variance. To determine if viral load could predict mortality, receiver operating characteristic (ROC) curves were constructed using area under the curve (AUC) of the viral load and peak viral concentration (V_max).

Results

Viral load (mean log₁₀ [AUC], peak viral load [V_max]) for patients with severe CMV disease was significantly higher compared with nondiseased patients (P < .001). Similarly, higher viral burden was significantly associated with mortality (P < .001). Viral load AUC and V_max AUROCs for predicting mortality were 0.796 and 0.824, respectively, for renal patients, and 0.769 and 0.807, respectively, for liver patients.

Conclusions

Using specimens from studies preceding the antiviral prophylaxis era, CMV viral load was associated with severe CMV disease and death, supporting CMV viral load quantification as a proxy for CMV disease severity and disease-associated mortality end points in solid organ transplantation.

Do we really need cadavers anymore to learn anatomy in undergraduate medicine?

With the availability of numerous adjuncts or alternatives to learning anatomy other than cadavers (medical imaging, models, body painting, interactive media, virtual reality) and the costs of maintaining cadaver laboratories, it was considered timely to have a mature debate about the need for cadavers in the teaching of undergraduate medicine. This may be particularly pertinent given the exponential growth in medical knowledge in other disciplines, which gives them valid justification for time in already busy medical curricula. In this symposium, the pros and cons of cadaver use in modern medical curricula were debated and audience participation encouraged.

Bioactive lipids serve as biomarkers of host immune response during severe influenza infection in pediatric patients

Influenza virus infects 5–20% of the population annually, leading to considerable morbidity and mortality especially in children. Robust biomarkers, reflecting the host immune response, are needed to identify patients at risk of prolonged illness or death. Eicosanoids, a family of bioactive arachidonic acid metabolites produced by the host in response to influenza infection, have pro- and anti-inflammatory properties. This study aimed to assess the relationship between the host lipid response at ICU admission with clinical outcomes in a multicenter cohort of 105 children with influenza-related illness (PICFLU study). We developed a mass spectrometry-based method to quantify &gt;100 lipid metabolites from nasopharyngeal swabs and endotracheal aspirates. The bioactive lipid profile in influenza infected children was impacted by multiple factors including patient age and bacterial coinfection. Patients coinfected with methicillin-resistant Staphylococcus aureus and influenza had significantly elevated levels of pro-inflammatory lipids and concomitantly lower levels of anti-inflammatory 15-lipoxygenase metabolites. Interestingly, children that presented with high levels of lipids including prostaglandin E2 and 12-hydroxyeicosatetraenoic acid were more likely to have fatal outcomes despite reports indicating these lipids have opposing immunomodulatory activity. These results suggest children at risk of mortality have an amplified bioactive lipid immune response that may negatively impact disease resolution. Our study provides evidence that bioactive lipids are potential prognostic biomarkers of patient immune response phenotype, and may help to identify children at risk of influenza-related death.

Generation and Protective Ability of Influenza Virus-Specific Antibody-Dependent Cellular Cytotoxicity in Humans Elicited by Vaccination, Natural Infection, and Experimental Challenge

BACKGROUND

Nonneutralizing antibodies (Abs) involved in antibody-dependent cellular cytotoxicity (ADCC) may provide some protection from influenza virus infection. The ability of influenza vaccines to induce ADCC-mediating Abs (ADCC-Abs) in adults and children is unclear.

METHODS

We quantified ADCC-Abs in serum samples from adults who received a dose of inactivated subunit vaccine (ISV) targeting monovalent 2009 pandemic influenza A(H1N1) virus or live-attenuated influenza vaccine (LAIV) or who had laboratory-confirmed influenza A(H1N1) virus infection. We also measured ADCC-Abs in children who either received a dose of trivalent seasonal ISV followed by trivalent seasonal LAIV or 2 doses of LAIV. Finally, we assessed the ability of low and high ADCC-Ab titers to protect adults from experimental challenge with influenza A/Wisconsin/67/131/2005(H3N2) virus.

RESULTS

Adults and children who received a dose of ISV had a robust increase in ADCC-Ab titers to both recombinant hemagglutinin (rHA) protein and homologous virus-infected cells. There was no detectable increase in titers of ADCC-Abs to rHA or virus-infected cells in adults and children who received LAIV. Higher titers (≥320) of preexisting ADCC-Abs were associated with lower virus replication and a significant reduction in total symptom scores in experimentally infected adults.

CONCLUSIONS

ADCC-Ab titers increased following experimental influenza virus infection in adults and after ISV administration in both children and adults.

A Phase II study of the efficacy and safety of rontalizumab (rhuMAb interferon-α) in patients with systemic lupus erythematosus (ROSE)

OBJECTIVES

To examine the safety and efficacy of rontalizumab, a humanised IgG1 anti-interferon α (anti-IFN-α) monoclonal antibody, in patients with moderate-to-severe systemic lupus erythematosus (SLE).

METHODS

Patients with active SLE were randomised (2:1) to 750 mg intravenous rontalizumab every 4 weeks or placebo (Part 1), and 300 mg subcutaneous rontalizumab every 2 weeks or placebo (Part 2).

BACKGROUND

Hydroxychloroquine and corticosteroids were allowed. Patients taking immunosuppressants at baseline were required per protocol to discontinue. Efficacy end points included reduction in disease activity by British Isles Lupus Disease Activity Group (BILAG)-2004 (primary), and SLE response index (SRI, secondary) at Week 24. Efficacy was also examined by an exploratory measure of IFN-regulated gene expression (interferon signature metric, ISM).

RESULTS

Patients (n=238) received rontalizumab (n=159) or placebo (n=79). At baseline, the mean Safety of Estrogens in Lupus Erythematosus National Assessment version of the SLE Disease Activity Index (SELENA-SLEDAI) score in all cohorts was ~10, and 75.6% of patients had a high ISM (ISM-High). Efficacy response rates by BILAG and SRI were similar between rontalizumab and placebo groups. However, in the exploratory subgroup of ISM-Low patients, SRI response was higher and steroid use was lower in the rontalizumab-treated patients. There was also a reduction in SELENA-SLEDAI flare index rates (HR 0.61, 0.46 to 0.81, p=0.004) in this subgroup. Adverse events were similar between placebo and rontalizumab groups.

CONCLUSIONS

The primary and secondary end points of this trial were not met in all patients or in patients with high ISM scores. In an exploratory analysis, rontalizumab treatment was associated with improvements in disease activity, reduced flares and decreased steroid use in patients with SLE with low ISM scores.

TRIAL REGISTRATION NUMBER

NCT00962832.

Association of the interferon signature metric with serological disease manifestations but not global activity scores in multiple cohorts of patients with SLE

Objectives

The interferon (IFN) signature (IS) in patients with systemic lupus erythematosus (SLE) includes over 100 genes induced by type I IFN pathway activation. We developed a method to quantify the IS using three genes—the IS metric (ISM)—and characterised the clinical characteristics of patients with SLE with different ISM status from multiple clinical trials.

Methods

Blood microarray expression data from a training cohort of patients with SLE confirmed the presence of the IS and identified surrogate genes. We assayed these genes in a quantitative PCR (qPCR) assay, yielding an ISM from the IS. The association of ISM status with clinical disease characteristics was assessed in patients with extrarenal lupus and lupus nephritis from four clinical trials.

Results

Three genes, HERC5, EPSTI and CMPK2, correlated well with the IS (p>0.96), and composed the ISM qPCR assay. Using the 95th centile for healthy control data, patients with SLE from different studies were classified into two ISM subsets—ISM-Low and ISM-High—that are longitudinally stable over 36 weeks. Significant associations were identified between ISM-High status and higher titres of anti-dsDNA antibodies, presence of anti extractable nuclear antigen autoantibodies, elevated serum B cell activating factor of the tumour necrosis factor family (BAFF) levels, and hypocomplementaemia. However, measures of overall clinical disease activity were similar for ISM-High and ISM-Low groups.

Conclusions

The ISM is an IS biomarker that divides patients with SLE into two subpopulations—ISM-High and ISM-Low—with differing serological manifestations. The ISM does not distinguish between high and low disease activity, but may have utility in identifying patients more likely to respond to treatment(s) targeting IFN-α.

Clinicaltrials.gov registration number

NCT00962832.

4-Aminopyridine derivatives enhance impulse conduction in guinea-pig spinal cord following traumatic injury

4-Aminopyridine (4-AP), a potassium channel blocker, is capable of restoring conduction in the injured spinal cord. However, the maximal tolerated level of 4-AP in humans is 100 times lower than the optimal dose in in vitro animal studies due to its substantially negative side effects. As an initial step toward the goal of identifying alternative potassium channel blockers with a similar ability of enhancing conduction and with fewer side effects, we have synthesized structurally distinct pyridine-based blockers. Using isolated guinea-pig spinal cord white matter and a double sucrose gap recording device, we have found three pyridine derivatives, N-(4-pyridyl)-methyl carbamate (100 microM), N-(4-pyridyl)-ethyl carbamate (100 microM), and N-(4-pyridyl)-tertbutyl (10 microM) can significantly enhance conduction in spinal cord white matter following stretch. Similar to 4-AP, the derivatives did not preferentially enhance conduction based on axonal caliber. Unlike 4-AP, the derivatives did not change the overall electrical responsiveness of axons to multiple stimuli, indicating the axons recruited by the derivatives conducted in a manner similar to healthy axons. These results demonstrate the ability of novel constructs to serve as an alternative to 4-AP for the purpose of reversing conduction deficits.

Effect of stretching on agonist-antagonist muscle activity and muscle force output during single and multiple joint isometric contractions

Eight moderately active male subjects where tested for peak force in an isometric knee extension test and peak force and rate of force development in an isometric squat test. Both tests where performed at a 100 degrees knee angle and average integrated electromyography (IEMG) was measured from the vastus medialis (VM), vastus lateralis (VL) and biceps femoris (BF) muscles. Subjects performed the two conditions, stretching (S) or control (C) in a randomized order. Subjects where tested for baseline strength measures in both the isometric knee extension and isometric squat and then either stretched or sat quietly for 10 min. Following S or C subjects where then tested at six time points. Following S peak force in the isometric knee extension was significantly (P < or = 0.05) less than C at 1, 2, 8 and 16 min post. No significant difference in peak force was found between S and C in the isometric squat. However, following S the rate of force development in the isometric squat was significantly less than C at immediately post. No significant differences where observed in IEMG of the VM or VL between S and C in either the isometric knee extension or isometric squat. However, IEMG significantly decreased in the BF at 1 min post after S in comparison with C in both the isometric knee extension and isometric squat. Stretching appears to decrease muscle force output in a single joint isometric contraction and rate of force development in a multiple joint isometric contraction. Possible changes in agonist-antagonist muscle activity patterns need to be further examined.

Effects of effort and EMG levels on short-latency stretch reflex modulation after varying background muscle contractions

It is known that the short-latency stretch reflex (SLSR) is modulated by the background muscle activity when it is elicited at matched torque levels. This study was designed to examine the effects of muscle contraction types before a stretch perturbation on SLSR in the human soleus muscle (SOL) when SLSR was elicited at the same levels of effort and at matched electromyographic (EMG) activity levels. A mechanical stretch perturbation was applied to the calf muscles when the ankle joint reached a ninety degree tibio-tarsal joint angle after the muscles performed an isometric (pre-ISO), shortening (pre-SHO) and lengthening contraction (pre-LEN). Subjects were seated on an ankle ergometer chair and developed 0%, 10%, 20%, 30%, 40%, 50%, 60% and 70% ankle joint torque (AJT) of maximum voluntary isometric plantar flexion contraction at 80 degrees in pre-SHO, at 90 degrees in pre-ISO and at 100 degrees in pre-LEN. After that, isometric or dynamic contractions started, and the subjects were asked to maintain effort levels as, needed, to maintain the target torque levels until the end of the stretch. They relaxed their muscles fully after the stretch. This chain of processes was consecutively repeated 10 times. EMG signals obtained from SOL were averaged after they were high-pass filtered and full-wave rectified. Some major findings resulted: (1) there were no differences in SLSR area in the active muscle between pre-ISO and pre-SHO, whereas its waveform was steeper in pre-ISO than in pre-SHO. (2) SLSR p-to-p amplitude and waveform were larger and steeper in the active muscle than in the relaxed one in all conditions, whereas they were independent of the effort levels once the muscle was activated. This led to steady SLSR modulation in response to the background muscle contraction in the active muscle regardless of whether the SLSR was elicited at matched AJT or EMG activity levels. These findings suggest that SLSR is closely related to the muscle spindle sensitivity influenced by the following factors: (1) the background muscle contraction type, and (2) gamma motoneuron activity set by CNS based on the effort level.

Effects of power training on muscle structure and neuromuscular performance

The present study examines changes in muscle structure and neuromuscular performance induced by 15 weeks of power training with explosive muscle actions. Twenty-three subjects, including 10 controls, volunteered for the study. Muscle biopsies were obtained from the gastrocnemius muscle before and after the training period, while maximal voluntary isometric contractions (MVC) and drop jump tests were performed once every fifth week. No statistically significant improvements in MVC of the knee extensor (KE) and plantarflexor muscles were observed during the training period. However, the maximal rate of force development (RFD) of KE increased from 18,836+/-4282 to 25,443+/-8897 N (P<0.05) during the first 10 weeks of training. In addition, vertical jump height (vertical rise of the center of body mass) in the drop jump test increased significantly (P<0.01). Simultaneously, explosive force production of KE muscles measured as knee moment and power increased significantly; however, there was no significant change (P>0.05) in muscle activity (electromyography) of KE. The mean percentage for myosin heavy chain and titin isoforms, muscle fiber-type distributions and areas were unchanged. The enhanced performance in jumping as a result of power training can be explained, in part, by some modification in the joint control strategy and/or increased RFD capabilities of the KE.

Interleukin 10 regulates cell surface and soluble LIR-2 (CD85d) expression on dendritic cells resulting in T cell hyporesponsivenessin vitro

Dendritic cells (DC) are unique in their ability to stimulate naive T cells to proliferate and to differentiate into effector T cells. DC, however, can also inhibit T cell activation and play a role in central and peripheral tolerance. IL-10 has been shown to render DC tolerogenic by unknown mechanisms. Using a combined monoclonal antibody/retroviral expression cloning approach, we show here that the inhibitory receptor LIR-2 (leukocyte immunoglobulin-like receptor-2, CD85d) is specifically up-regulated by IL-10 on maturing human DC. LPS-stimulated, LIR-2-transfected DC inhibited the proliferation of T cells in autologous, as well as allogeneic culture systems in vitro. In addition, overexpression of LIR-2 on resting T cells, which lack LIR-2 expression, inhibited T cell proliferation induced by TCR activation. A novel soluble form of LIR-2 was detected in culture supernatants of maturing DC. IL-10 treatment of DC potently inhibited the production of soluble LIR-2. Recombinant soluble LIR-2 was able to completely restore the proliferation of T cells activated with LPS-plus IL-10-treated DC. Thus, IL-10 renders DC hypostimulatory by up-regulating cell surface LIR-2 and by inhibiting soluble LIR-2 in vitro.

Effects of power training on mechanical efficiency in jumping

The present study investigates the effects of power training on mechanical efficiency (ME) in jumping. Twenty-three subjects, including ten controls, volunteered for the study. The experimental group trained twice a week for 15 weeks performing various jumping exercises such as drop jumps, hurdle jumps, hopping and bouncing. In the maximal jumping test, the take-off velocity increased from 2.56 (0.24) m.s(-1) to 2.77 (0.18) m.s(-1) ( P<0.05). In the submaximal jumping of 50% of the maximum, energy expenditure decreased from 660 (110) to 502 (68) J.kg(-1).min(-1) ( P<0.001) while, simultaneously, ME increased from 37.2 (8.4)% to 47.4 (8.2)% ( P<0.001). Some muscle enzyme activities of the gastrocnemius muscle increased during the training period: citrate synthase from 35 (8) to 39 (7) micromol.g(-1) dry mass.min(-1) ( P<0.05) and beta-hydroxyacyl CoA dehydrogenase from 21 (4) to 23 (5) micromol.g(-1) dry mass.min(-1) ( P<0.05), whereas no significant changes were observed in phosphofructokinase and lactate dehydrogenase. In the control group, no changes in ME or in enzyme activities were observed. In conclusion, the enhanced performance capability of 8% in maximal jumping as a result of power training was characterized by decreased energy expenditure of 24%. Thus, the increased neuromuscular performance, joint control strategy, and intermuscular coordination (primary factors), together with improved aerobic capacity (secondary factor), may result in reduced oxygen demands and increased ME.

A complicated relationship: fulfilling the interactive needs of the T lymphocyte and the dendritic cell

T cells recognize antigenic peptides displayed on the surface of MHC-bearing antigen-presenting cells (APCs), and with sufficient costimulation become activated. However, the ability of an APC (even bearing the correct peptide) to initiate and fulfill the requirements for T cell activation is not easily achieved. Naive T cells use multiple copies of a single receptor to survey the vast array of peptides presented on an APC, and require multiple receptor engagements to initiate T cell activation. Dendritic cells (DCs) are specialized cells with optimal capabilities for priming naive CD4+ T cells. Activation occurs, after initial antigen recognition by T cells, followed by a rapid dialogue between the T cells and the DCs. The resulting changes in both the cytoskeleton and the expression or regulation of cell-surface molecules on both cell types act to further strengthen engagement. In this report, we review the fundamentals of CD4+ T helper cell : DC interactions and discuss recent data concerning the molecular characteristics of this engagement.

Stretch-reflex mechanical response to varying types of previous muscle activities

This study was designed to examine the effects of varying types of background muscle activity on the stretch-reflex mechanical response. A rapid stretch was applied to the calf muscles after an isometric (pre-ISO), shortening (pre-SHO) and lengthening contraction (pre-LEN) with several pre-contraction levels, respectively. The stretch perturbation was applied with the tibio-tarsal joint angle at 90 degrees. The ankle joint torque elicited by the stretch showed a first peak (non-reflex torque: NRT), a transient drop and a second peak (reflex torque: RT). The muscle activities before the stretch clearly influenced the stretch-reflex mechanical response. The NRT reached the largest peak with the longest duration in pre-ISO. The peak NRT increased with the pre-contraction level in pre-ISO and pre-LEN, whereas it remained unchanged in pre-SHO. The RT responded to the stretch-reflex EMG response most quickly and reached the largest peak in pre-ISO. Pre-ISO generated the mechanical response most efficiently against the size of the stretch-reflex EMG response. Pre-SHO showed lower peak RT than pre-ISO in spite of the similar size of stretch-reflex EMG response. The peak RT was closely related to the peak NRT in all conditions. Consequently, the peak RT also increased with the pre-contraction level in pre-ISO and pre-LEN, whereas it remained unchanged in pre-SHO. In conclusion, a stretch after an isometric contraction evoked a larger stretch-reflex mechanical response more efficiently than that after phasic contractions when a given effort was being maintained.

Short-latency stretch reflex modulation in response to varying soleus muscle activities

The current investigation examined the effect of various types of background muscle contractions on the short-latency stretch reflex (SLR) elicited from the soleus muscle while subjects were in a sitting position. A stretch was applied to the calf muscles while they performed an isometric (pre-ISO), shortening (pre-SHO) and lengthening contraction (pre-LEN) with several pre-contraction levels. The ankle was at a 90 degrees tibio-tarsal joint angle when the perturbation was applied. Subjects developed and maintained a given pre-load level, which was maintained at various percentages of the maximum voluntary isometric plantar flexion torque. This was performed at 80 degrees in pre-SHO, 90 degrees in pre-ISO and 100 degrees in pre-LEN for about 2s before the contractions. The SLRs in trials with 0, 35 and 50% of the maximum voluntary contraction torque level were compared among the three conditions. The main results were as follows. (1) Pre-ISO and pre-SHO showed an equal SLR area and a different SLR waveform in the active muscle. (2) Pre-LEN showed the smallest SLR area of three conditions in the active muscle. (3) Pre-LEN showed shorter SLR latencies than the other conditions. (4) Pre-SHO showed a longer SLR latency in the relaxed muscle than in the active muscle. (5) The SLR area was larger in the active muscle than in the relaxed muscle. These findings demonstrate that the muscle contraction type and the pre-contraction level before a stretch perturbation have a considerable influence on the latency, the area and the waveform of the SLR. In particular, the equal area and the different waveforms of the SLR between pre-ISO and pre-SHO were a unique finding in the present study. They might result from differences in muscle spindle sensitivity and afferent input from various receptors induced by the present motor task.

IL-10 alters DC function via modulation of cell surface molecules resulting in impaired T-cell responses

IL-10 is a potent inhibitor of T-cell activation and has tolerizing effects on these cells. These effects are primarily mediated via modulation of antigen presenting cell function. Here, it is demonstrated that IL-10 completely inhibits LPS-induced DC maturation, resulting in altered DC-T-cell interactions and reduced T-cell responses. IL-10 inhibited LPS-induced upregulation of costimulatory molecules, MHC Class II, and the secretion of IL-12, TNF-alpha, IL-6, and IL-1beta by DCs, although it upregulated the SLAM (CD150) expression at both the mRNA and protein levels. IL-10 pre-treated DC did not respond to subsequent LPS activation and its stimulatory ability for allogeneic and antigen-specific T-cells was severely impaired. Importantly, T-cells derived from co-cultures with Ag-pulsed, IL-10-treated DC were impaired in their responses to subsequent Ag-specific restimulation. Transwell and DC-derived plasma membrane experiments indicated that the capacity of IL-10-treated DC to induce T-cell unresponsiveness results from alterations in the cell surface molecules rather than modulation of cytokine secretion.

Changes in myosin heavy chain composition with heavy resistance training in 60- to 75-year-old men and women

The purpose of this investigation was to assess the myosin heavy chain (MHC) expression in the vastus lateralis muscle from elderly men and women, and to determine whether heavy resistance training influences its expression. Twenty healthy, mildly physically active subjects gave their informed consent to participate in the study. The experimental group consisted of seven men and seven women [mean (SD) age 65.5 (4.1) years] and the control group consisted of three men and three women [mean (SD) age 62.3 (3.6) years]. The 6-month resistance training program was divided into two phases with weeks 1-12 consisting of high-intensity resistance training, and weeks 13-24 involving power training. Muscle biopsy samples were taken from the vastus lateralis muscle at week 0 and week 24 using the needle biopsy technique. The male and female experimental groups both exhibited a significant decrease (P < or = 0.05) in the percentage of MHC IIb, while the experimental female group also demonstrated a significant increase (P < or = 0.05) in the expression of MHC IIa, after 24 weeks of heavy resistance training. There was no change in MHC expression within the control group. The male [130.4 (25.3) kg vs 171.1 (30.5) kg] and female [58.2 (8.3) kg vs 77.9 (11.1) kg] experimental groups exhibited a significant increase (P < or = 0.05) in the maximal strength values for the 1 repetition maximum (1RM) squat exercise. The control group showed no change in strength for the 1RM squat exercise for either the male [115.8 (35.10 kg vs 123.8 (47.2) kg] or female [57.5 (99.0) kg vs 58.3 (2.9) kg] groups. The results clearly show that elderly subjects undergoing heavy resistance training have the ability to produce a similar shift in the expression of MHC isoforms from MHC IIb to MHC IIa, as has been shown to occur in younger subjects. This highlights the plasticity of human skeletal muscle in response to heavy resistance training, even at older ages.

Influence of exercise training on physiological and performance changes with weight loss in men

PURPOSE

The purpose of this study was to examine the physiological effects of a weight-loss dietary regimen with or without exercise.

METHODS

Thirty-five overweight men were matched and randomly placed into either a control group (C; N = 6) or one of three dietary groups; a diet-only group (D; N = 8), a diet group that performed aerobic exercise three times per week (DE; N = 11); and a diet group that performed both aerobic and strength training three times per week (DES; N = 10).

RESULTS

After 12 wk, D, DE, and DES demonstrated a similar and significant (P < or = 0.05) reduction in body mass (-9.64, -8.99, and -9.90 kg, respectively) with fat mass comprising 69, 78, and 97% of the total loss in body mass, respectively. The diet-only group also demonstrated a significant reduction in fat-free mass. Maximum strength, as determined by 1-RM testing in the bench press and squat exercise was significantly increased for DES in both the bench press (+19.6%) and squat exercise (+32.6%). Absolute peak O2 consumption was significantly elevated in DE (+24.8%) and DES (+15.4%). There were no differences in performance during a 30-s Wingate test for the DE and DES, whereas D demonstrated a significant decline in peak and mean power output. Resting metabolic rate (RMR) (kcal x d(-1)) was not significantly different for any of the groups except for the DE group. There were no significant changes in basal concentrations of serum glucose, BUN, cortisol, testosterone, and high density lipoprotein (HDL) cholesterol for any of the groups. Serum total cholesterol and low density lipoprotein (LDL) cholesterol were significantly decreased for all dietary groups. Serum triglycerides were significantly reduced for D and DES at week 6 and remained lower at week 12 for D, while triglycerides returned to baseline values for DES.

CONCLUSIONS

These data indicate that a weight-loss dietary regimen in conjunction with aerobic and resistance exercise prevents the normal decline in fat-free mass and muscular power and augments body composition, maximal strength, and maximum oxygen consumption compared with weight-loss induced by diet alone.

Effect of resistance exercise on free radical production

The purposes of this investigation were to see whether free radical production changed with high intensity resistance exercise and, secondly, to see whether vitamin E supplementation would have any effect on free radical formation or variables associated with muscle membrane disruption. Twelve recreationally weight-trained males were divided into two groups. The supplement group (S) received 1200 IUs of vitamin E once a day (3 x 400 IU x d[-1]) for a period of 2 wk. The placebo group (P) received cellulose-based placebo pills once a day for the same period of time. Creatine kinase activity was significantly elevated between preexercise and immediately postexercise, 6 h postexercise, and 24 h postexercise for both groups. The placebo group also had a significant increase in creatine kinase activity at 48 h postexercise. There was a significant difference in creatine kinase activity between the groups at 24 h after exercise. Plasma malondialdehyde significantly increased from preexercise levels for the P group at 6 and 24 h postexercise. Plasma malondialdehyde concentrations significantly increased in the S group between preexercise and immediately postexercise levels. This study indicates that high intensity resistance exercise increases free radical production and that vitamin E supplementation may decrease muscle membrane disruption.

Plasma proenkephalin peptide F and human B cell responses to exercise stress in fit and unfit women

In vitro studies have connected immune cell function to Peptide F. The primary purpose of this investigation was to examine the responses of plasma Peptide F and epinephrine along with the changes in B cell antibody production in vivo in physically fit and unfit women in response to physical exercise on a cycle ergometer at 60% and 80% of peak oxygen consumption. Seven aerobically fit and eight untrained (i.e., unfit) women between the ages of 18 and 30 volunteered to participate in this investigation. Blood samples (analyzed for plasma Peptide F and epinephrine along with the number of antibody-producing B cells) were obtained 24 hours prior to the exercise session, pre-exercise, during each exercise intensity, and five minutes post-exercise. The fit group had a significantly higher plasma Peptide F concentration after the 80% exercise intensity along with significantly higher numbers of antibody producing B cells compared to the unfit group. The results of this investigation show that physically fit women have an enhanced secondary response of B cells to a specific antigen under conditions where Peptide F is increased. Such data demonstrate that physical fitness as promoted by the Public Health Service (e.g., Healthy People 2000) influences the underlying hormonal and immune cell responses when challenged by physical exercise stress.

Physiological adaptations to a weight-loss dietary regimen and exercise programs in women

Thirty-one women (mean age 35.4 +/- 8.5 yr) who were overweight were matched and randomly placed into either a control group (Con; n = 6), a diet-only group (D; n = 8), a diet+aerobic endurance exercise training group (DE; n = 9), or a diet+aerobic endurance exercise training+strength training group (DES; n = 8). After 12 wk, the three dietary groups demonstrated a significant (P </= 0.05) reduction in body mass, %body fat, and fat mass. No differences were observed in the magnitude of loss among groups, in fat-free mass, or in resting metabolic rate. The DE and DES groups increased maximal oxygen consumption, and the DES group demonstrated increases in maximal strength. Weight loss resulted in a similar reduction in total serum cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol among dietary groups. These data indicate that weight loss during moderate caloric restriction is not altered by inclusion of aerobic or aerobic+resistance exercise, but diet in conjunction with training can induce remarkable adaptations in aerobic capacity and muscular strength despite significant reductions in body mass.

Responses of IGF-I to endogenous increases in growth hormone after heavy-resistance exercise

The purpose of this study was to examine the effects of a heavy-resistance exercise protocol known to dramatically elevate immunoreactive growth hormone (GH) on circulating insulin-like growth factor I (IGF-I) after the exercise stimulus. Seven men (23.1 +/- 2.4 yr) volunteered to participate in this study. Each subject was asked to perform an eight-station heavy-resistance exercise protocol consisting of 3 sets of 10 repetition maximum resistances with 1-min rest between sets and exercises followed by a recovery day. In addition, a control day followed a nonexercise day to provide baseline data. Pre- and postexercise (0, 15, and 30 min) blood samples were obtained and analyzed for lactate, creatinine kinase, GH, and IGF-I. Postexercise values for lactate and GH were significantly (P < 0.05) elevated above preexercise and resting baseline values. The highest mean GH concentration after the heavy-resistance exercise protocol was 23.8 +/- 11.8 micrograms/l, observed at the immediate postexercise time point. Significant increases in creatine kinase were observed after the exercise protocol and during the recovery day. No significant relationships were observed between creatine kinase and IGF-I concentrations. No significant changes in serum IGF-I concentrations were observed with acute exercise or between the recovery and control days. Thus, these data demonstrate that a high-intensity bout of heavy-resistance exercise that increases circulating GH did not appear to affect IGF-I concentrations over a 24-h recovery period in recreationally strength-trained and healthy young men.

Automated order-entry mechanisms to influence prescribing

On-line prescribing is available in many hospitals in the United States and has distinct advantages. On-line drug prescribing can be influenced by the use of automated prompts that guide and direct the prescriber to the preferred agent, dosage, or regimen. The authors have adapted screen prompts to facilitate appropriate prescribing as defined by pharmacy and therapeutic (P&T) committee decisions, restricted drug or target drug initiatives, drug-usage evaluation (DUE) actions, departmental guidelines and order-sets, and other institutional directives. Objective evidence for the effectiveness of on-line prompts is provided for H2-antagonists and antibiotics. As computer technology advances even further and is increasingly utilized in the health care setting, on-line interventions to facilitate appropriate prescribing may become increasingly useful.

Physician usage of the computer to access a hospital information system

This retrospective descriptive study was undertaken to determine the characteristics of physicians who use the computer to access a Hospital Information System (HIS). A convenience sample of 630 staff physicians at a 640-bed metropolitan tertiary care teaching medical center was analyzed utilizing the variables of age, specialty, years in practice, gender, and frequency of use. A significant difference (p < or = .01) in age was found with the user physician being younger than the nonuser; no significance was found (p < or = .01) in specialty, years in practice, or gender.

Hospital mainframe computer documentation of pharmacist interventions

The hospital mainframe computer pharmacist intervention documentation system described has successfully facilitated the recording, communication, analysis, and reporting of interventions at our hospital. It has proven to be time efficient, accessible, and user-friendly from the standpoint of both the pharmacist and administrator. The advantages of this system greatly outweigh manual documentation and justify the initial time investment in its design and development. In the future, it is hoped that the system can have even broader impact. Intervention/recommendations documented can be made accessible to medical and nursing staff, and as such further increase interdepartmental communication. As pharmacists embrace the pharmaceutical care mandate, documenting interventions in patient care will continue to grow in importance. Complete documentation is essential if pharmacists are to assume responsibility for patient outcomes. With time being an ever-increasing premium, and with economic and human resources dwindling, an efficient and effective means of recording and tracking pharmacist interventions will become imperative for survival in the fiscally challenged health care arena. Documentation of pharmacist intervention using a hospital mainframe computer at UIH has proven both efficient and effective.

Mechanical Stress and Reactivity in Organic Solids

Organic single crystals provide an ideal model for studying the factors that influence chemical processes in structured media. Reaction trajectories are well defined and reveal the influence of spontaneous mechanical stresses equivalent to tens of thousands of atmospheres. Analysis of molecular and crystal structures helps to explain both local mechanical properties, which influence reactions, and bulk properties such as melting point, compressibility, and surface energy.