R2Play development: Fostering user-driven technology that supports return-to-play decision-making following pediatric concussion

Objective

To design a multi-domain return-to-play assessment system (R2Play) for youth athletes with concussion.

Methods

The R2Play system was developed using an overarching user-centered approach, the Design Thinking Framework, and research activities included: 1) structured brainstorming within our research team, 2) interviews with clinician and youth sports coaches, 3) building a testable prototype, and 4) interface testing through cognitive walkthroughs with clinician partners.

Results

Clinician and coach participants provided feedback on the R2Play concept, which was integrated into the design process and provided future directions for research. Examples of feedback-driven design choices included reducing assessment time, increasing ecological validity by adding in background noise, and developing youth-friendly graphical results screens. Following refinement based on stakeholder feedback, the R2Play system was outlined in detail and a testable prototype was developed. It is made up of two parts: a clinician tablet, and a series of tablet "buttons" that display numbers and letters. Youth athletes run between the buttons to connect a "trail" in ascending alphanumeric order, 1-A-2-B, etc. Their performance across a series of levels of increasing difficulty is logged on the clinician tablet. Initial testing with five clinicians showed the system's interface to have excellent usability with a score of 81% (SD = 8.02) on the System Usability Scale.

Conclusion

Through this research, a prototype of the R2Play system was innovated and evaluated by clinician and coach stakeholders. Initial usability was excellent and directions for future iterations were highlighted. Outcomes suggest the potential benefits of using technologies to assist in complex clinical assessment, as well as utilizing a user-centered approach to design.

Adolescent and parent experiences with Tele-Active Rehabilitation for concussion: an exploratory qualitative study

PURPOSE

To explore the experiences of adolescents with concussion and their parents who participated in a novel remotely delivered Tele-Active Rehabilitation (Tele-AR) intervention involving sub-symptom threshold exercise, education, and support. Specifically, we aimed to elicit perspectives regarding the remote delivery approach, valued aspects of the program, and perceived benefits of the intervention.

METHODS

This qualitative study took place within the context of a larger mixed-methods project exploring the feasibility of the Tele-AR intervention. A descriptive qualitative design was utilized. Semi-structured interviews were conducted with adolescents (n = 3; ages 14-17 years) with concussion and one of their parents (n = 3) within one week of completing the six-week Tele-AR intervention. Data were analyzed using thematic analysis.

RESULTS

Four themes were identified that capture participant experiences in the intervention: (1) Enabling access to active rehabilitation; (2) Focusing on individual needs; (3) Learning to take responsibility for recovery; and (4) Convenience and comfort of engaging in rehabilitation from home.

CONCLUSIONS

A small sample of 3 adolescents with concussion and their parents were satisfied with the Tele-AR intervention and appreciated the convenience and comfort of engaging in rehabilitation from home, which facilitated adolescents taking responsibility for their own recovery. Findings support continued study of Tele-AR, which may be an accessible intervention to facilitate recovery in adolescents with concussion.

Tele-Active Rehabilitation for Youth With Concussion: Evidence-Based and Theory-Informed Intervention Development

BACKGROUND

Active rehabilitation involving subsymptom threshold exercise combined with education and support promotes recovery in youth with concussion but is typically delivered in person, which may limit accessibility for families because of a lack of services in their communities or logistical challenges to attending in-person sessions.

OBJECTIVE

This paper describes the evidence-based and theory-informed development of the Tele-Active Rehabilitation (Tele-AR) intervention for pediatric concussion, which was specifically designed for remote service delivery.

METHODS

The intervention was designed by clinician-researchers with experience in pediatric concussion rehabilitation following the Medical Research Council guidance for developing complex interventions. Development involved a critical review of the literature to identify existing evidence, the expansion of the theoretical basis for active rehabilitation, and the modeling of the intervention process and outcomes.

RESULTS

Tele-AR is a 6-week home exercise and education and support program facilitated through weekly videoconferencing appointments with a clinician. Exercise consists of low- to moderate-intensity subsymptom threshold aerobic activity and coordination drills that are individualized to participant needs and interests (prescribed for 3 days per week). Education includes the evidence-supported Concussion & You self-management program, which covers topics related to energy management, nutrition, hydration, sleep hygiene, and return to activity. Elements of self-determination theory are incorporated to support motivation and engagement. We present a logic model describing predicted intervention effects using a biopsychosocial conceptualization of outcomes after concussion.

CONCLUSIONS

The Tele-AR intervention may help to increase access to care that improves recovery and promotes a timely return to activity in youth with concussion. Future research is needed to evaluate the feasibility and efficacy of this approach.

CDC field triage criteria accurately predicts outcomes in high impact trauma

BACKGROUND

The precision of emergency medical services (EMS) triage criteria dictates whether an injured patient receives appropriate care. The trauma triage protocol is a decision scheme that groups patients into triage categories of major, moderate and minor. We hypothesized that there is a difference between trauma triage category and injury severity score (ISS).

METHODS

This retrospective, observational study was conducted to investigate a difference between trauma triage category and ISS. Bivariate analysis was used to test for differences between the subgroup means. The differences between the group means on each measure were analyzed for direction and statistical significance using ANOVA for continuous variables and chi square tests for categorical variables. Logistic and linear regressions were performed to evaluate factors predicting mortality, ICU length of stay.

RESULTS

With respect to trauma triage category, our findings indicate that minor and moderate triage categories are similar with respect to ISS, GCS, ICU LOS, hospital LOS, and mortality. However, after excluding for low impact injuries (falls), differences between the minor and moderate categories were evident when comparing to ISS, GCS, ICU LOS, and hospital LOS. Additionally, after excluding for low impact injures, ISS, ICU LOS, and hospital stay were found to correlate well with trauma triage category.

CONCLUSIONS

In this retrospective, observational study significant differences were not seen when comparing ISS with the trauma triage categories of moderate and minor during our initial analysis. However, a difference was found after excluding for low impact injuries. These findings suggest that CDC criteria accurately predicts outcomes in high impact trauma.

Thematic Analysis of Parent-Child Conversations About COVID-19: "Playing It Safe"

Caregivers have primary responsibility for teaching their children self-protective behaviors, including those behaviors recommended by the Center for Disease Control (CDC) to prevent the spread of COVID-19. Parents have an important role in scaffolding adherence to the CDC recommendations and in managing stress and regulate their emotions to adaptively cope during uncertain times like those facing communities nationwide. The present study is a qualitative, thematic analysis of parent-reported (n = 210; 64.8% female; average age = 39.33; 14.3% ethnic/racial minority) interactions with children (focal child age: 25.2% birth to 5 years old, 36.7% 6 to 11 years old, 37.6% 12 to 18 years old) about topics associated to COVID-19-related viral transmission suppression guidelines and stress/coping behaviors. Themes included discussions about personal and social hygiene, and parent reported sources of child stress, and child stress management efforts. Findings from our thematic analysis indicate parents are motivated to make scaffolding personal hygiene fun and engaging, signaling a positive, developmentally appropriate native approach to their role as sources of coping socialization. These findings also underscore the importance of providing information to parents in ways that can be translated to children in developmentally appropriate conversations about viral transmission suppression activities and stress management during disasters.

Betanodavirus infection in Kuhlia rupestris and Ambassis marianus and isolation of betanodavirus from infected pond water

This is the first report of betanodavirus infection in 2 species of finfish, Kuhlia rupestris (jungle perch) and Ambassis marianus (estuary perchlet). This report also describes isolation of betanodavirus from infected pond water using the SSN-1 cell line. Histopathology of K. rupestris larvae revealed vacuolation in the eye and brain, which was confirmed using betanodavirus-specific immunohistochemistry. The eye and brain from A. marianus and betanodavirus isolated from pond water were confirmed using real-time PCR and Sanger sequencing. High throughput sequencing was used to obtain betanodavirus sequences from paraffin blocks containing infected K. rupestris. The phylogenetic analysis of betanodavirus RNA1 and RNA2 sequences from all 3 sources were associated with the red-spotted grouper nervous necrosis virus (RGNNV) genotype. The RNA1 nucleotide sequence from jungle perch showed 100% identity with the betanodavirus water isolate and 99.37% identity with A. marianus. Furthermore, we have demonstrated the usefulness of combining recovery of viable virus from environmental samples through fish cell line culture with PCR testing as a means of validating the efficacy of chlorination to eradicate betanodavirus from the pond environment.

Initial Challenges of Caregiving During COVID-19: Caregiver Burden, Mental Health, and the Parent-Child Relationship

Research confirms that the mental health burdens following community-wide disasters are extensive, with pervasive impacts noted in individuals and families. It is clear that child disaster outcomes are worst among children of highly distressed caregivers, or those caregivers who experience their own negative mental health outcomes from the disaster. The current study used path analysis to examine concurrent patterns of parents' (n = 420) experience from a national sample during the early months of the U.S. COVID-19 pandemic. The results of a multi-group path analysis, organized by parent gender, indicate good fit to the data [X²(10) = 159.04, p < .01]. Results indicate significant linkages between parents' caregiver burden, mental health, and perceptions of children's stress; these in turn are significantly linked to child-parent closeness and conflict, indicating possible spillover effects for depressed parents and compensatory effects for anxious parents. The impact of millions of families sheltering in place during the COVID-19 pandemic for an undefined period of time may lead to unprecedented impacts on individuals' mental health with unknown impacts on child-parent relationships. These impacts may be heightened for families whose caregivers experience increased mental health symptoms, as was the case for fathers in the current sample.

Testing the Hybrid Battery Approach to Evaluating Sports-Related Concussion in the National Hockey League: A Factor Analytic Study

Purpose

Traditional “paper and pencil” neuropsychological tests and computerized test batteries have been employed in the assessment of sports-related concussion (SRC). Each type of test has inherent strengths and weaknesses. The NHL has constructed a “hybrid” battery of tests that uses both traditional and computerized measures in the evaluation of its players suspected of SRC. The purpose of this paper is to use factor analytic techniques to examine the relationships among the measures that comprise this battery.

Methods

Post-injury neuropsychological test data using the hybrid battery were obtained from 343 NHL players following their first concussion while playing in the league. ImPACT was used as the computer test battery. The traditional battery included: Hopkins Verbal Learning Test, Brief Visuospatial Memory Test, Color Trails, PSU Cancellation, Symbol Digits Modalities Test (including incidental memory), and Verbal Fluency.

Results

Five factors were extracted explaining 64.55% of the variance. The factor labels and the measures principally loading on each factor were as follows: Factor 1, Verbal Learning and Memory (HVLT Total and Delayed Recall); Factor 2, Processing Speed (Color Trails A/B, PSU Cancellation, and SDMT-Total); Factor 3, Visual Memory (BVMT- Total and Delayed); Factor 4, Cued Memory (ImPACT-Visual and Verbal Memory Composites); and Factor 5, Reaction Time (ImPACT Reaction Time and Visual Motor Speed composites).

Conclusion

These data underscore the unique contributions of traditional and ImPACT neuropsychological measures to the evaluation SRC in a sample of professional hockey players. It appears that both approaches measure different aspects of cognitive functioning. The next logical step is to use these data in evaluating the diagnostic utility of these measures as part of a combined battery.

The Utility of the King-Devick Test in Evaluating Professional Ice Hockey Players with Suspected Concussion

Purpose

The King-Devick (KD) is a measure of rapid number naming used in the evaluation of sports-related concussion (SRC). Recent data from the Canadian Football League and Rugby Union suggest that the KD should not be used as a stand-alone measure of SRC. The purpose of this study was to examine the diagnostic utility of the KD in professional ice hockey players.

Methods

NHL players who were suspected of having a concussion were evaluated with the KD and either the SCAT3 or the SCAT5. Players who were evaluated and not diagnosed with concussion served as Active controls. A small group of non-Active control players was also tested twice and was included in the present study for comparison.

Results

1605 players were evaluated with the KD at baseline. Of these, 53 were diagnosed with concussion, 76 were Active controls, and 11 were non-Active controls. Concussed players revealed a decline in performance from baseline to acute evaluation, t(52)=3.05, p<.01, d=.42 while Active controls significantly improved, t(75)=2.05, p<.05, d=.24. No significant change between baseline and acute testing was observed for non-Active controls. Using a cut score of any decline in performance from baseline to suspected injury evaluation yielded Sensitivity=64%, Specificity=61%, Positive Predictive Value=53% and Negative Predictive Value=71%.

Conclusion

Our data are consistent with previous studies suggesting that while the KD is useful in differentiating concussed and not concussed athletes acutely, the relatively low predictive values indicate that a decline in KD performance should not be used as a standalone measure to diagnose concussion.

Two baselines are better than one: Improving the reliability of computerized testing in sports neuropsychology

Computerized neuropsychological tests are frequently used to assist in return-to-play decisions following sports concussion. However, due to concerns about test reliability, the Centers for Disease Control and Prevention recommends yearly baseline testing. The standard practice that has developed in baseline/postinjury comparisons is to examine the difference between the most recent baseline test and postconcussion performance. Drawing from classical test theory, the present study investigated whether temporal stability could be improved by taking an alternate approach that uses the aggregate of 2 baselines to more accurately estimate baseline cognitive ability. One hundred fifteen English-speaking professional hockey players with 3 consecutive Immediate Postconcussion Assessment and Testing (ImPACT) baseline tests were extracted from a clinical program evaluation database overseen by the National Hockey League and National Hockey League Players' Association. The temporal stability of ImPACT composite scores was significantly increased by aggregating test performance during Sessions 1 and 2 to predict performance during Session 3. Using this approach, the 2-factor Memory (r = .72) and Speed (r = .79) composites of ImPACT showed acceptable long-term reliability. Using the aggregate of 2 baseline scores significantly improves temporal stability and allows for more accurate predictions of cognitive change following concussion. Clinicians are encouraged to estimate baseline abilities by taking into account all of an athlete's previous baseline scores.

Metabolism by conjugation appears to confer resistance to paracetamol (acetaminophen) hepatotoxicity in the cynomolgus monkey

1. Paracetamol overdose remains the leading cause of acute liver failure in humans. This study was undertaken in cynomolgus monkeys to study the pharmacokinetics, metabolism and the potential for hepatotoxic insult from paracetamol administration as a possible model for human toxicity. 2. No adverse effects were observed for doses of up to 900 mg/kg/d for 14 d. Only minor sporadic increases in alanine aminotransferase, aspartate aminotransferase and glutamate dehydrogenase in a number of animals were observed, with no clear dose response. 3. Toxicokinetic analysis showed good plasma exposure, albeit with less than proportional rises in Cmax and AUC, with increasing dose. The Cmax values in monkey were up to 3.5 times those associated with human liver toxicity and the AUC approx. 1000 times those associated with liver enzyme changes in 31-44% of human subjects. 4. Metabolite profiling of urine by (1)H NMR spectroscopy revealed paracetamol and its glucuronide and sulphate metabolites. Glutathione-derived metabolites, e.g. the cysteinyl conjugate, were only present in very low concentrations whilst the mercapturate was not detected. 5. These in vivo observations demonstrated that the cynomolgus monkey is remarkably resistant to paracetamol-induced toxicity and a poor model for investigating paracetamol-related hepatotoxicity in humans.

Concussions and heading in soccer: a review of the evidence of incidence, mechanisms, biomarkers and neurocognitive outcomes

BACKGROUND

Soccer is currently the most popular and fastest-growing sport worldwide. Similar to many sports, soccer carries an inherent risk of injury, including concussion. Soccer is also unique in the use of 'heading'. The present paper provides a comprehensive review of the research examining the incidence, mechanisms, biomarkers of injury and neurocognitive outcomes of concussions and heading in soccer.

METHODS

Seven databases were searched for articles from 1806 to 24 May 2013. Articles obtained by the electronic search were reviewed for relevance, with 229 selected for review. Ultimately, 49 articles met criteria for inclusion in the present review.

RESULTS

Female soccer players have a higher incidence of concussions than males. The most frequent injury mechanism is player-to-player contact for both genders. Few studies examined the effects of concussion in soccer players; however, neurocognitive outcomes were similar to those reported in the larger sport concussion literature, while the effect of heading is less clear.

CONCLUSION

Despite variation in research designs and study characteristics, the outcomes of concussions in soccer align with the greater concussion literature. This review makes recommendations for future research to increase standardization of research for improved understanding of concussions in soccer as well as the effects of heading.

Drug-drug interactions and metabolism in cytochrome P450 2C knockout mice: application to troleandomycin and midazolam

Drug-drug interactions (DDIs) may cause serious drug toxicity and delay development of candidate drugs. Screening using human liver microsomes and hepatocytes can help predict DDIs but do not always provide the degree of certainty required for confident progression of a candidate drug. Thus a suitable in vivo test system could be of great value. Here a Cyp2c knockout (KO) mouse was investigated for studying DDIs using midazolam (MDZ) a standard human CYP3A4 substrate and troleandomycin (TAO) a potent human CYP3A4 inhibitor. Pharmacokinetics (PK) and biotransformation of MDZ were investigated following dosing to Cyp2c KO and wild type mice before and after TAO treatment. The noteworthy differences in the metabolism of MDZ in Cyp2c KO compared to wild type mice confirms the important role that Cyp2c enzymes play in the murine metabolism of MDZ in vivo. The impact of Cyp3a inhibition produced a further increase in circulating MDZ concentrations in all individuals from both strains of mice though the impact of the elimination of the Cyp2c pathway in the KO mice on the AUC was less than perhaps expected. We have shown that TAO produces an increase in the MDZ concentration and a reduction in the 1'hydroxymidazolam/midazolam formation ratio but the expected difference in the magnitude of this effect between the wild type and the Cyp2c KO mice was not seen. The magnitude of the TAO effect was also smaller than is reported in humans. Hence further work is required before this animal model could be used to predict clinical interactions.

The influence of musculoskeletal injury on cognition: implications for concussion research

BACKGROUND

Safe return-to-play decisions after concussion can be challenging for sports medicine specialists. Neuropsychological testing is recommended to objectively measure concussion-related cognitive impairments.

PURPOSE

The objective of this study was to measure cognitive functioning among 3 specific athletic groups: (1) athletes with no injuries (n = 36), (2) athletes with musculoskeletal injuries (n = 18), and (3) athletes with concussion (n = 18).

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Seventy-two intercollegiate athletes completed preseason baseline cognitive testing and follow-up assessment using the Automated Neuropsychological Assessment Metrics (ANAM) test battery. Injured athletes were tested within 72 hours of injury. A 1-way analysis of covariance adjusted for baseline scores was performed to determine if differences existed in cognitive test scores among the 3 groups.

RESULTS

A group of athletes with concussion performed significantly worse than a group of athletes with no injuries on the following subtests of the ANAM at follow-up: Code Substitution Learning, Match to Sample, and Simple Reaction. Athletes with musculoskeletal injuries performed significantly worse than those with no injury on the Match to Sample subtest. No significant differences between athletes with concussion and athletes with musculoskeletal injuries were found on all ANAM subtests.

CONCLUSION

Concussion produces cognitive impairment in the acute recovery period. Interestingly, athletes with musculoskeletal injuries also display a degree of cognitive impairment as measured by computerized tests.

CLINICAL RELEVANCE

Although these findings support previous research that neuropsychological tests can effectively measure concussion-related cognitive impairment, this study provides evidence that athletic injury, in general, also may produce a degree of cognitive disruption. Therefore, a narrow interpretation of scores of neuropsychological tests in a sports concussion context should be avoided.

Emotional response to sport concussion compared to ACL injury

PRIMARY OBJECTIVES

To ascertain and compare the nature of emotional response of athletes to concussion and to anterior cruciate ligament (ACL) injury.

RESEARCH DESIGN

Pre-injury, post-injury and longitudinal emotional functioning of athletes with concussion (n = 16), athletes with ACL injuries (n = 7) and uninjured athletes (n = 28) were compared in a prospective repeated-measures design.

METHODS AND PROCEDURES

Participants completed the short version of the Profile of Mood States (POMS). ANOVAs and trend analysis were used to examine between and within group differences across time on two sub-scales, Total Mood Disturbance and Depression.

MAIN OUTCOMES AND RESULTS

Athletes with ACL injury reported higher levels of depression for a longer duration than athletes with concussion. Relative to un-injured controls, athletes with concussion reported significant changes in Total Mood Disturbance and Depression post-injury, whereas athletes with ACL injuries reported significant changes in Depression scores only. Different patterns of post-injury emotional disturbance for the injured groups were observed by trend analyses.

CONCLUSIONS

Concussed athletes do not report as much emotional disturbance as athletes with ACL injuries. Differential patterns of emotional disturbance were detected between injured groups. The authors recommended that clinical protocols and educational programmes address emotional sequelae associated with sport concussion and ACL injury.

Cytochrome P450-dependent metabolism of gefitinib

The in vitro metabolism of [(14)C]-gefitinib (1-3 microM) was investigated using human liver microsomes and a range of expressed human cytochrome P450 enzymes, with particular focus on the formation of O-desmethyl-gefitinib (M523595), the major metabolite observed in human plasma. High-performance liquid chromatography with ultraviolet light, radiochemical and mass spectral analysis, together with the availability of authentic standards, enabled quantification and structural identification of metabolites. On incubation with pooled human liver microsomes, [(14)C]-gefitinib underwent rapid and extensive metabolism to a number of metabolites, although M523595 was only a minor microsomal product. Formation of most metabolites was markedly decreased by ketoconazole, but M523595 production was inhibited only by quinidine. Gefitinib was metabolized extensively by expressed CYP3A4, producing a similar range of metabolites to liver microsomes, but M523595 was not formed. CYP1A2, 2C9 and 2C19 produced no measurable metabolism of gefitinib, while CYP3A5 produced a range of metabolites similar to CYP3A4, but to a much lower degree. In contrast, CYP2D6 catalysed rapid and extensive metabolism of gefitinib to M523595. While formation of M523595 was CYP2D6 mediated, the overall metabolism of gefitinib was dependent primarily on CYP3A4, and this was not obviously diminished in liver microsomes from CYP2D6 poor metabolizers.

In vitrometabolism of gefitinib in human liver microsomes

The in vitro metabolism of gefitinib was investigated by incubating [14C]-gefitinib, as well as M537194, M387783 and M523595 (the main metabolites of gefitinib observed in man), at a concentration of 100 microM with human liver microsomes (4 mg ml(-1)) for 120 min. These relatively high substrate and microsomal protein concentrations were used in an effort to generate sufficient quantities of metabolites for identification. HPLC with ultraviolet light, radiochemical and mass spectral analysis, together with the availability of authentic standards, enabled quantification and structural identification of a large number of metabolites. Although 16 metabolites were identified, metabolism was restricted to three regions of the molecule. The major pathway involved morpholine ring-opening and step-wise removal of the morpholine ring and propoxy side chain. O-demethylation of the quinazoline methoxy group was a quantitatively less important pathway, in contrast to the clinical situation, where O-desmethyl gefitinib (M523595) is the predominant plasma metabolite. The third metabolic route, oxidative defluorination, was only a minor route of metabolism. Some metabolites were formed by a combination of these processes, but no metabolism was observed in other parts of the molecule. Incubation of gefitinib produced ten identified metabolites, but the use of the three main in vivo metabolites as additional substrates enabled a more comprehensive metabolic pathway to be constructed and this has been valuable in supporting the more limited data available from the human in vivo study.

Metabolic disposition of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in rat, dog and man

Following oral administration of [14C]-gefitinib to albino and pigmented rats, radioactivity was widely and rapidly distributed, with the highest levels being found in liver, kidney, lung and gastrointestinal tract, but with only low levels penetrating the brain. Levels of radioactivity persisted in melanin-containing tissues (pigmented eye and skin). Binding to plasma proteins was high (86-94%) across the range of species examined and was 91% in human plasma. Substantial binding occurred to both human serum albumin and alpha-1 acid glycoprotein. Following oral and intravenous administration of [14C]-gefitinib, excretion of radioactivity by rat, dog and human occurred predominantly via the bile into faeces, with < 7% of the dose being eliminated in urine. In all three species, gefitinib was cleared primarily by metabolism. In rat, morpholine ring oxidation was the major route of metabolism, leading to the formation of M537194 and M608236 as the main biliary metabolites. Morpholine ring oxidation, together with production of M523595 by O-demethylation of the quinazoline moiety, were the predominant pathways in dog, with oxidative defluorination also occurring to a lesser degree. Pathways in healthy human volunteers were similar to dog, with O-demethylation and morpholine ring oxidation representing the major routes of metabolism.

Pharmacokinetics of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in rat and dog

The pharmacokinetics of gefitinib and its metabolites in rat and dog were investigated in preclinical studies conducted to support the safety evaluation and clinical development of gefitinib, the first EGFR tyrosine kinase inhibitor approved for the treatment of non-small-cell lung cancer. Following intravenous dosing (5 mg kg(-1), gefitinib plasma half-life was 3-6h in rats and dogs, although studies using a more sensitive HPLC-MS assay produced longer estimates of half-life (7-14h). In these studies, plasma clearance was high (male rat: 25 ml min(-1) kg(-1); female rat: 16 ml min(-1) kg(-1); male dog: 16 ml min(-1) kg(-1)), as was the volume of distribution (8.0-10.41 kg(-1) in rat; 6.31 kg(-1) in dog), and exposure in female rats was double that in males. Following administration of [14C]-gefitinib, concentrations of radioactivity in plasma exceeded gefitinib throughout the profile, indicating the presence of circulating metabolites in both rat and dog. An HPLC-MS assay was developed to measure concentrations of gefitinib and five potential metabolites in plasma. All five metabolites were detected in the rat, but at levels much lower than gefitinib. In the dog, exposure to gefitinib and M523595 was similar, with much lower concentrations of M537194 and only trace levels of the other metabolites. This profile of metabolites is similar to that observed in man.

Minimal contribution of desmethyl-gefitinib, the major human plasma metabolite of gefitinib, to epidermal growth factor receptor (EGFR)-mediated tumour growth inhibition

Desmethyl-gefitinib is a major metabolite of gefitinib observed in human plasma at concentrations similar to those of gefitinib. The epidermal growth factor receptor (EGFR)-related inhibitory effects of gefitinib and desmethyl-gefitinib have been compared both in vitro, using enzyme kinase assays and tumour cell growth inhibition, and in vivo by assessment of tumour xenografts growth inhibition in the mouse. Both gefitinib (IC(50) = 0.022 microM) and its desmethyl metabolite (0.036 microM) inhibited subcellular EGFR tyrosine kinase activity with a similar potency and selectivity. However, desmethyl-gefitinib (IC(50) = 0.76 microM) was 15 times less active than gefitinib (0.049 microM) against EGF-stimulated KB cell growth in a whole cell assay. Following a preliminary pharmacokinetic study to compare apparent oral bioavailability, gefitinib (75 mg kg(-1)) and desmethyl-gefitinib (150 mg kg(-1)) were administered orally for 15 days to female nude mice bearing LoVo tumour xenografts. Tumour concentrations of gefitinib (AUC = 300 microg h g(-1)) were much higher than those of desmethyl-gefitinib (44.3 microg h g(-1)), although plasma concentrations of gefitinib (48.4 microg h ml(-1)) and desmethyl-gefitinib (39.0 microg h ml(-1)) were quite similar at these dose levels. Gefitinib produced significant tumour growth inhibition throughout the course of the study ultimately resulting in a 50% decrease (compared with controls) by day 15. In contrast, although present at comparable plasma levels, desmethyl-gefitinib had little effect on tumour growth and is, therefore, considered unlikely to contribute significantly to the therapeutic activity of gefitinib in the clinical situation.

Presence of Salmonella in the red meat abattoir lairage after routine cleansing and disinfection and on carcasses

Foodborne pathogens, such as Salmonella, may remain in abattoir lairages after cleansing and pose a risk of transfer and contamination from one processing day to the next. These organisms may be transferred to the outer surface of animals held in lairage facilities, and the skin or hide may be a significant source of microbial contamination on the red meat carcasses subsequently produced. Sponge samples were taken from various sites in the lairage (n = 556), and single-pass sponge samples were taken from one side of red meat carcasses (n = 1,050) at five commercial abattoirs in Southwest England and tested for the presence of Salmonella. Of these, 6.5% of lairage samples were positive, containing estimated numbers of up to 10(4) Salmonella organisms per sampled area (50 by 50 cm). Salmonella was found on 9.6% of 240 lamb carcasses, 12.7% of 330 beef carcasses, 31% of 70 pig carcasses, 20% of 80 calf carcasses younger than 14 days of age, and none of 330 cull cow and bull carcasses. Subtyping divided the 137 isolates into seven serogroups and three pulsed-field gel electrophoresis clusters, and sensitivity testing against a bank of 16 antimicrobials indicated that 47 isolates had resistance to one or more antimicrobial agents. These results indicate that Salmonella contamination can persist in the lairage environment from one processing day to the next and that Salmonella is present on red meat carcasses, although the implications of residual lairage contamination on carcass meat microbiology are not clear from this study. Abattoir owners should take steps to reduce the level of contamination in their premises to prevent contamination from being carried over from one processing day to the next.

Impact of intraaortic balloon counterpulsation on arterial blood flow in juvenile pigs with heart failure

OBJECTIVES

To assess the impact of intraaortic balloon counterpulsation on coronary, renal and aortic blood flow in an animal heart failure model.

BACKGROUND

Heart failure exacerbations are still often treated with inotropic medications despite a lack of evidence demonstrating any benefit with these drugs. Intraaortic balloon counterpulsation may be considered in certain cases a bridge to recovery.

METHODS

Four juvenile pigs underwent pacemaker implantation to induce a rapid-pacing mediated dilated cardiomyopathy. After approximately 4 weeks of rapid pacing, the mean ejection fraction was reduced to 28.8+/-9.5% with a mean systolic blood pressure of 64/44 mmHg. The pigs then underwent surgical placement of flow probes around the circumflex coronary artery, renal artery and infrarenal aorta. A Millar catheter was used to calculate Dp/Dt and a Swan-Ganz to calculate cardiac output. Data were recorded at baseline and after 10 minutes of balloon pumping. The pigs were euthanized post-procedure.

RESULTS

Coronary blood flow was increased 9.7% by balloon counterpulsation from 38.3 +/- 12.0 to 42.0+/-11.4 ml/s (p=NS). Renal blood flow was reduced 11.9% by counterpulsation from 130.0+/-88.6 ml/s to 114.5+/-76.6 ml/s (p=NS). Infrarenal aortic blood flow was not changed (mean of 900 ml/s with and without counterpulsation); blood pressure, cardiac output and Dp/Dt were not changed after 10 minutes of pumping. There was little impact observed by changing the position of the balloon closer to or farther away from the apex of the aortic arch.

CONCLUSION

Intraaortic balloon counterpulsation did not significantly improve hemodynamics in the pig heart failure model. This may be attributed to the high compliance of the juvenile pig's aorta, thus attenuating the pressure wave generated by counterpulsation. A larger volume balloon would merit investigation for this application.

The normal population distribution of PRNP codon 129 polymorphism

OBJECTIVES

The common prion protein gene (PRNP) codon 129 polymorphism modifies the susceptibility to and the phenotype of prion diseases. However, no truly representative normal population-based data, or data stratified according to age or gender are available on the distribution of this polymorphism.

MATERIAL AND METHODS

Allelic variation of codon 129 in three Finnish populations representing different age groups, and among Finnish, British and Irish blood donors were examined.

RESULTS

The PRNP codon 129 genotype distribution in the total Finnish sample was 49% for methionine-methionine (MM), 42% for methionine-valine (MV) and 9% for valine-valine (VV), for the UK blood donors 42% for MM, 47% for MV and 11% for VV, and for the Irish blood donors 34% for MM, 56% for MV, and 10% for VV.

CONCLUSIONS

The genotype frequencies were almost identical in all three Finnish populations of different ages, with no gender differences, and did not differ from corresponding figures for the Finnish blood donors. However, the PRNP codon 129 genotype distribution in Finland differed significantly from that of the British and the Irish blood donors and the previously published blood donor data on other Western Europeans and Americans.

Distribution and function of EGFR in human tissue and the effect of EGFR tyrosine kinase inhibition

From immunohistochemical and ligand-binding studies, it is known that the epidermal growth factor receptor (EGFR), a member of the erbB family of receptors, is expressed in tissues of epithelial, mesenchymal and neuronal origin and plays a major role in normal cellular processes such as proliferation, differentiation and development. EGFR is highly expressed in a number of solid tumours and its expression correlates with tumour progression, resistance to chemotherapy and a poor prognosis; it is consequently an attractive target for the rational design of novel anticancer agents. Knowledge of the role of EGFR in normal tissues will help the understanding of the adverse events associated with such agents. Studies in knockout mice and preclinical toxicology studies have shown that the major effects of inhibiting the EGFR are skin and gastrointestinal toxicities. Clinical studies with inhibitors of EGFR, such as gefitinib, cetuximab and erlotinib, have shown a favourable adverse-event profile, primarily consisting of skin and gastrointestinal toxicities, as predicted from the mechanism-based effects observed in preclinical studies.

Phase I study of ZD9331 on short daily intravenous bolus infusion for 5 days every 3 weeks with fixed dosing recommendations

PURPOSE

To conduct a phase I study of ZD9331, a potent, nonpolyglutamatable thymidylate synthase inhibitor using a short daily infusion for 5 consecutive days every 21 days.

PATIENTS AND METHODS

Patients with refractory cancer or cancer for which no standard therapy was available were treated in escalating doses using an accelerated titration design. Plasma and urine samples were collected at timed intervals in the first cycle for pharmacokinetic analysis.

RESULTS

Seventy-four patients were enrolled at 12 dose levels from a starting dose of 0.4 mg/m(2)/d to 16 mg/m(2)/d and 25 mg/d fixed dosing, of which 67 were assessable for toxicity. Maximum-tolerated dose was reached at 16 mg/m(2)/d. Myelosuppression was dose-limiting, consisting of thrombocytopenia associated with neutropenic fever. Body-surface area did not correlate with drug clearance; therefore, fixed daily dosing of 25 mg/d was studied and found to be tolerable, with two of 12 dose-limiting events. Dose-limiting nonhematologic toxicity consisted of grade 3 erythematous maculopapular rash observed in one patient at 12 mg/m(2)/d and one patient at 25 mg/d. Pharmacokinetic analysis showed nonlinearity, with clearance increasing with dose. The mean clearance and terminal half-life of the drug were 6.6 +/- 2.0 mL/min and 71.3 +/- 27.0 hours, respectively. Area-under-the concentration-time curve was a better predictor of toxicity than dose, using multiple linear regression analyses. Minor response (40% shrinkage of tumor) was observed in one patient with colorectal cancer treated at 12 mg/m(2)/d.

CONCLUSION

The recommended dose for ZD9331 on this schedule is 25 mg/d. Neutropenia, thrombocytopenia, and rash were dose-limiting, and efficacy studies in colorectal cancer are indicated.

Isolation of the protein kinase TAO2 and identification of its mitogen-activated protein kinase/extracellular signal-regulated kinase kinase binding domain

We previously reported the cloning of the thousand and one-amino acid protein kinase 1 (TAO1), a rat homolog of the Saccharomyces cerevisiae protein kinase sterile 20 protein. Here we report the complete sequence and properties of a related rat protein kinase TAO2. Like TAO1, recombinant TAO2 selectively activated mitogen-activated protein/extracellular signal-regulated kinase kinases (MEKs) 3, 4, and 6 of the stress-responsive mitogen-activated protein kinase pathways in vitro and copurified with MEK3 endogenous to Sf9 cells. To examine TAO2 interactions with MEKs, the MEK binding domain of TAO2 was localized to an approximately 135-residue sequence just C-terminal to the TAO2 catalytic domain. In vitro this MEK binding domain associated with MEKs 3 and 6 but not MEKs 1, 2, or 4. Using chimeric MEK proteins, we found that the MEK N terminus was sufficient for binding to TAO2. Catalytic activity of full-length TAO2 enhanced its binding to MEKs. However, neither the autophosphorylation of the MEK binding domain of TAO2 nor the activity of MEK itself was required for MEK binding. These results suggest that TAO proteins lie in stress-sensitive kinase cascades and define a mechanism by which these kinases may organize downstream targets.

Isolation of TAO1, a protein kinase that activates MEKs in stress-activated protein kinase cascades

Several components of the budding yeast pheromone-response pathway are conserved in mammalian mitogen-activated protein (MAP) kinase pathways. Thus, we used degenerate oligonucleotides derived from the sequence of the Saccharomyces cerevisiae protein kinase Ste20p to amplify related sequences from the rat. One of these sequences was used to clone a rat Ste20p homolog, which we called TAO1 for its one thousand and one amino acids. Northern analysis shows TAO1 is highly expressed in brain, as is a homolog TAO2. Recombinant TAO1 was expressed and purified from Sf9 cells. In vitro, it activated MAP/extracellular signal-regulated protein kinase (ERK) kinases (MEKs) 3, 4, and 6 of the stress-responsive MAP kinase pathways, but not MEK1 or 2 of the classical MAP kinase pathway. TAO1 activated MEK3 but not MEK4 or MEK6 in transfected cells. MEK3 coimmunoprecipitated with TAO1 when they were expressed in 293 cells. In addition, immunoreactive MEK3 endogenous to Sf9 cells copurified with TAO1 produced from a recombinant baculovirus. The activation of and binding to MEK3 by TAO1 implicates TAO1 in the regulation of the p38-containing stress-responsive MAP kinase pathway.

Pharmacokinetics of meropenem in critically ill patients with acute renal failure treated by continuous hemodiafiltration

The pharmacokinetics of meropenem were studied in nine anuric critically ill patients treated by continuous venovenous hemodiafiltration. Peak levels after infusion of 1,000 mg over 30 min amounted to 103.2 +/- 45.9 microgram/ml, and trough levels at 12 h were 9.6 +/- 3.8 microgram/ml. A dosage of 1,000 mg of meropenem twice a day provides plasma drug levels covering intermediately susceptible microorganisms. Further reductions of the dosage might be appropriate for highly susceptible bacteria or when renal replacement therapies with lower clearances are applied.