Stakeholder-Engaged Development of a Theory-Driven, Feasible, and Acceptable Approach to Concussion Education

Concussion education is widely mandated and largely ineffective. Recent consensus guidance on concussion education asserts the importance of (1) theory-driven programming that targets the team as a system and (2) working with end users throughout the development process, and considering issues such as feasibility, acceptability, and sustainability. Consistent with this guidance, and in collaboration with youth sport stakeholders in two regions of the United States, we developed a novel approach to concussion education: Pre-game safety huddles. Safety huddles have the following two core components: (1) athletes, coaches, and other stakeholders come together before the start of each game and (2) opinion leaders (coaches, referees) affirm the importance of care seeking for suspected concussion. The aim of this article is to provide an overview of the collaborative process through which we refined the safety huddle concept into an acceptable and feasible intervention with potential for sustainable implementation in diverse youth sports settings with minimal resource demands. In describing our process and discussing challenges and opportunities, we hope to provide an example for others seeking to develop and implement injury prevention interventions in youth sports settings.

Project nature: promoting outdoor physical activity in children via primary care

BACKGROUND

Families face a range of barriers in supporting their children's active play in nature including family circumstances, environmental constraints, and behavioral factors. Evidence-based strategies to address these barriers are needed. We aimed to develop and pilot test a primary care-based family-centered behavioral intervention to promote active outdoor play in 4-10 year-old children.

METHODS

Project Nature, a provider-delivered intervention that provides informational resources and an age-appropriate toy for nature play, was initially developed for children ages 0-3. With stakeholder input, we adapted existing materials for 4-10 year-olds and conducted usability testing at an urban clinic serving families from diverse backgrounds. Subsequently, we conducted a mix-methods pilot study to evaluate intervention feasibility and acceptability. Parents of 4-10 year-olds completed pre- and post-surveys (n = 22), and a purposive subset (n = 10) completed qualitative interviews. Post-intervention, pediatric providers (n = 4) were interviewed about their implementation experiences.

RESULTS

The majority (82%) of parents liked the information provided and the remaining (18%) were neutral. Qualitatively, parents reported that: the toy provided a tangible element to help children and parents be active, they did not use the website, and they wished the intervention emphasized strategies for physical activity during cold and wet seasons. Providers felt the materials facilitated discussion about behavior change with families. There were no statistically significant changes in PA and outdoor time pre- and post-intervention.

CONCLUSIONS

Project Nature was welcomed by providers and families and may be a practical intervention to promote outdoor active play during well-child visits. Providing an age-appropriate nature toy seemed to be a critical component of the intervention, and may be worth the additional cost, time and storage space required by clinics. Building from these results, Project Nature should be revised to better support active outdoor play during suboptimal weather and evaluated to test its efficacy in a fully-powered trial.

Developing a conceptual model of coach concussion communication by adapting the theory of planned behavior and the social ecological model

Objective: Acknowledging that coach communication about concussion increases the likelihood of athletes reporting concussive symptoms, the goal of this study was to examine factors affecting such communication, in order to develop a conceptual model that would inform the design of future educational interventions.Participants: Division I contact sport coaches.Methods: We conducted structured qualitative interviews with coaches and analyzed interviews using Thematic Analysis, viewed through the lens of the Theory of Planned Behavior nested within the Social Ecological Model.Results: Coaches had good knowledge of concussion and understood the dangers of playing with symptoms. However, they also discussed the lack of objective criteria for concussion diagnosis, and pressure to win in order to remain employed, both of which created barriers to concussion communication. Ultimately, most coaches reported not engaging in significant concussion communication as they did not feel this was their role, instead deferring to medical staff.Conclusions: Educational interventions might benefit from a focus on the importance of coach concussion safety-supportive coach communication, with a goal of increasing the likelihood of athlete concussion reporting.

Direct Determination of Fission-Barrier Heights Using Light-Ion Transfer in Inverse Kinematics

We demonstrate a new technique for obtaining fission data for nuclei away from β stability. These types of data are pertinent to the astrophysical r process, crucial to a complete understanding of the origin of the heavy elements, and for developing a predictive model of fission. These data are also important considerations for terrestrial applications related to power generation and safeguarding. Experimentally, such data are scarce due to the difficulties in producing the actinide targets of interest. The solenoidal-spectrometer technique, commonly used to study nucleon-transfer reactions in inverse kinematics, has been applied to the case of transfer-induced fission as a means to deduce the fission-barrier height, among other variables. The fission-barrier height of ^{239}U has been determined via the ^{238}U(d,pf) reaction in inverse kinematics, the results of which are consistent with existing neutron-induced fission data indicating the validity of the technique.

Feasibility and acceptability of at-home play kits for middle school physical activity promotion during the COVID-19 pandemic

BACKGROUND

Schools are central to providing opportunities for youth physical activity (PA), however such opportunities were limited during the COVID-19 pandemic. Identifying feasible, acceptable, and effective approaches for school-based PA promotion amid pandemic-related barriers can inform resource allocation efforts in future circumstances necessitating remote instruction. The aims of this study were to: (1) describe the pragmatic, stakeholder-engaged and theory-informed approach employed to adapt one school's PA promotion efforts to pandemic restrictions, leading to the creation of at-home "play kits" for students, and (2) assess the feasibility, acceptability, and preliminary effectiveness of this intervention.

METHODS

Intervention activities occurred in one middle school (enrollment: 847) located in a Federal Opportunity Zone in the Seattle, WA area, with control data from a nearby middle school (enrollment: 640). Students at the intervention school were eligible to receive a play kit during the quarter they were enrolled in physical education (PE) class. Student surveys were completed across the school year (n = 1076), with a primary outcome of days/week that the student engaged in ≥ 60 min of PA. Qualitative interviews (n = 25) were conducted with students, staff, parents, and community partners, and focused on play kit acceptability and feasibility.

RESULTS

During remote learning play kits were received by 58% of eligible students. Among students at the intervention school only, students actively enrolled in PE (versus not enrolled) reported significantly more days with ≥ 60 min of PA in the previous week, however the comparison between schools was not statistically significant. In qualitative interviews, most students reported the play kit motivated them to participate in PA, gave them activity ideas, and made virtual PE more enjoyable. Student-reported barriers to using play kits included space (indoors and outdoors), requirements to be quiet at home, necessary but unavailable adult supervision, lack of companions to play outdoors, and inclement weather.

CONCLUSIONS

A pre-existing community organization-school partnership lent itself to a rapid response to meet student needs at a time when school staff and resources were highly constrained. The intervention developed through this collaborative response-play kits-has potential to support middle school PA during future pandemics or other conditions that necessitate remote schooling, however modifications to the intervention concept and implementation strategy may be needed to improve reach and effectiveness.

Concussion education for youth athletes using Pre-Game Safety Huddles: a cluster-randomised controlled trial

OBJECTIVES

Determine whether Pre-Game Safety Huddles, a novel and low-resource approach to concussion education, increase the expected likelihood of concussion reporting for youth athletes.

METHODS

A cluster-randomised trial compared Safety Huddles to usual care. Safety Huddles bring together athletes and coaches from both teams before the start of each game for coaches to briefly affirm the importance of speaking up if a concussion is suspected. Participants were athletes from 22 competitive community-based American football and girls and boys soccer teams (ages 9-14), and randomisation into intervention or control occurred at the level of the bracket (group of teams that compete against each other during the regular season). The primary outcome was expected likelihood of reporting concussion symptoms to the coach, measured via validated athlete survey at the beginning and end of the season.

RESULTS

Of 343 eligible participants, 339 (99%) completed baseline surveys and 303 (88%) completed surveys at season end. The mean (SD) age was 11.4 (1.1) years, 26% were female soccer athletes, 27% were male soccer athletes and 47% were football athletes. In adjusted analyses accounting for baseline values and clustering by sport and team via random effects, expected likelihood of concussion reporting at the end of the season was significantly higher in the intervention group compared to controls (mean difference=0.49, 95% CI 0.11 to 0.88; Cohen's d=0.35).

CONCLUSIONS AND RELEVANCE

Pre-Game Safety Huddles increased the expected likelihood of athletes reporting concussion symptoms. While further study is warranted, sport organisations should consider this approach a promising low-resource option for improving concussion safety in their setting.

TRIAL REGISTRATION NUMBER

NCT04099329.

Quenching of Single-Particle Strength in A=15 Nuclei

Absolute cross sections for the addition of s- and d-wave neutrons to ^{14}C and ^{14}N have been determined simultaneously via the (d,p) reaction at 10  MeV/u. The difference between the neutron and proton separation energies, ΔS, is around -20  MeV for the ^{14}C+n system and +8  MeV for ^{14}N+n. The population of the 1s_{1/2} and 0d_{5/2} orbitals for both systems is reduced by a factor of approximately 0.5 compared with the independent single-particle model, or about 0.6 when compared with the shell model. This finding strongly contrasts with results deduced from intermediate-energy knockout reactions between similar nuclei on targets of ^{9}Be and ^{12}C. The simultaneous technique used removes many systematic uncertainties.

A diverse diet as an alternative to ryegrass can improve the total antioxidant status of dams at lambing

The objective of this experiment was to determine if providing ewes in the final trimester of pregnancy with choice from diverse diet components would reduce markers of oxidative and metabolic stress in ewes and improve lamb birth weights relative to ewes offered only one forage species, repetitively. Fifty-four, twin bearing Coopworth ewes [initial live weight (LW) = 69.82 ± 1.16 kg] were blocked by weight onto iso-energetic diets with either choice from taxonomically diverse plants [DIV; spatially separated strips of ryegrass (Lolium perenne L.), chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.), red clover (Trifolium pratense L.), and alfalfa (Medicago sativa L.)] or a ryegrass only diet (RYE) for the final third of gestation. The ewes offered the DIV diet birthed 8.9% heavier lambs (5.64 ± 0.20 kg) than RYE ewes (5.18 ± 0.20 kg; P = 0.03). In addition, the DIV ewes had greater (P < 0.01) glutathione peroxidase and total antioxidant status, and lower (P = 0.01) plasma non-esterified fatty acid concentrations than the RYE fed ewes 24 h after lambing. The results indicate that the DIV diet can improve antioxidant status and reduce some markers of oxidative and metabolic stress at lambing compared to a conventional RYE diet.

Development of a scale to measure expected concussion reporting behavior

Background

Most concussion education aims to increase athlete self-report of concussive symptoms. Although the population burden of concussion is high, frequency with which this injury occurs on a given sports team in a given season is relatively low. This means that powering concussion education evaluation studies to measure change in post-injury symptom reporting behavior requires what is often a prohibitively large sample size. Thus, evaluation studies are typically powered to measure proximal cognitions. Expected reporting behavior, a cognition that reflects planned and reactive decision-making, is a theoretically indicated construct for inclusion in evaluation studies. However, previously no scales were available to measure this construct with demonstrated reliability and validity among youth athletes. The objective of this study was to develop and assess the validity of a brief single-factor scale to measure expected youth athlete concussion reporting behavior (CR-E) in a sample of youth athletes.

Methods

A mixed methods approach was used, including cognitive interviews with youth athletes, and quantitative item reduction and validation. Participants were youth athletes (aged 9–16) from the Seattle metropolitan and rural south-Georgia regions. After refining an initial pool of items using cognitive interviews with a diverse group of youth athletes (n = 20), a survey containing these items was administered to youth soccer and football players (n = 291). Item reduction statistics and sequential confirmatory factor analyses were used to reduce the initial scale using a randomly selected half of the sample. Then, a final confirmatory factor analysis and validation tests were applied to the other half of the sample of youth athletes. Predictive validation was conducted longitudinally in a separate sample of youth athletes (n = 155).

Results

Internal consistency was high (alpha = 0.89), model fit was excellent, validation tests were in the hypothesized directions, and the scale was feasible to use. Using the finalized 4-item scale, we observed that less than one-third of youth soccer and football athletes expect to “always” tell their coach about symptoms of a suspected concussion.

Conclusions

The CR-E measure should be included in future studies evaluating concussion education programming in youth athlete populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40621-021-00364-4.

Effectiveness of an Education Platform (GoHuddle) for Increasing Likelihood of Coach Concussion Communication with Athletes

Research suggests coaches play a central role in establishing a context conducive to concussion reporting, particularly via direct verbal communication about concussion. Informed by qualitative interviews and stakeholder feedback, we developed a web-based concussion education platform for collegiate coaches (GoHuddle). The goal of GoHuddle is to encourage concussion safety-supportive coach communication using behavioral modeling and experiential learning. We then conducted a pre-post survey study to examine the impact of engaging with the platform on coach concussion communication, with outcomes of: (a) expected likelihood of communicating with athletes about concussive symptom reporting; (b) expected likelihood of pressuring medical staff to return athletes to play; and (c) belief in the usefulness of engaging in the communication described in a and b (i.e., response efficacy). We also assessed feasibility and acceptability of the platform in the collegiate sport context. The platform was sent to 435 coaches at five institutions, and 334 (77%) completed surveys (70% male, 37.8 years mean age). After completing GoHuddle, coaches had 2.5 greater odds of expecting to discuss concussion with their team (odds ratio [OR] 2.53, p < 0.001). Response efficacy for talking about concussion also increased significantly post-intervention (OR 3.78, p < 0.001). No significant change was seen in expectancies regarding pressure on medical staff to return athletes to play "as soon as possible." A high proportion (82%) of coaches would recommend this platform for coach concussion education. In conclusion, this study suggests GoHuddle is a feasible and acceptable approach to coach concussion education, and use of this platform holds promise for shifting coach communication about concussion.

Rumen function and grazing behavior of early-lactation dairy cows supplemented with fodder beet

Fodder beet (FB) is a source of readily fermentable carbohydrate that can mitigate early spring herbage deficits and correct the negative energy balance experienced during early lactation in pastoral dairy systems of New Zealand. However, the low-fiber and high-soluble carbohydrate content of both FB bulb and spring herbage are factors that promote subacute ruminal acidosis, impairing rumen function and limiting the marginal milk production response to supplement. In a crossover experiment, 8 Holstein Friesian × Jersey early-lactation dairy cows were used to test the effect of supplementing 16 kg of dry matter (DM) of a grazed perennial ryegrass herbage with 6 kg of DM/d of FB bulb (FBH) versus herbage only (HO) on changes in rumen function and grazing behavior. Following 20 d of adaptation to diets, DM disappearance (%) of FB bulb (FBH cows only) and herbage were measured in sacco, separately. Cows were fasted overnight, and the ruminal contents were bailed the following morning (~0930 h) again to determine the pool size of volatile fatty acids, ammonia, and particle size of digesta, as well as to estimate the rate of ruminal outflow and degradation of neutral detergent fiber. The FBH diet did not alter DM intake, milk yield, or milk solid (fat + protein) production compared with HO. Supplementation of herbage with FB reduced ruminal pH compared with HO between ~0800 h and 1300 h each day. During each period, 1 cow experienced severe subacute ruminal acidosis (pH <5.6 for >180 min/d) during final adaptation to the target FB allocation. The FBH diet reduced the ruminal pool of acetate and ammonia, but increased the ruminal pool of butyrate and lactate compared with HO. When fed FB, rumination and grazing time increased and grazing intensity declined compared with cows fed HO. Despite increased rumination, the comminution of large particles declined 28% between the first and second rumen bailing when cows were fed FB, and in sacco DM disappearance of perennial ryegrass declined 18% compared with cows fed HO. These results indicate that grazing dairy cows supplemented with FB (40% of daily intake) increase rumination and mastication intensity to counteract reduced ruminal degradation of ryegrass herbage due to low ruminal fluid pH.

Evaluation of PEETER V1.0 urine sensors for measuring individual urination behavior of dairy cows

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PEETER V1.0 sensors are a simple and inexpensive way to monitor cow urination behavior

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PEETER V1.0 sensors were found to have excellent accuracy

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PEETER V1.0 sensors were shown to have excellent precision

Due to environmental concerns around N leaching and NO₂ emissions from intensive pastoral dairying systems, there has been an increase in research focused on mitigation strategies and on-animal technologies to evaluate urination behavior of grazing dairy cows. Nitrogen leaching and NO₂ emissions are associated with urine nitrogen loading onto pasture, which is a function of urine nitrogen concentration and urine volume per urination event. The PEETER V1.0 urine sensor (Lincoln University, Christchurch, New Zealand) is a promising on-animal measurement technology; however, it has yet to be validated in vivo. The objective of this work was to validate the PEETER V1.0 urine sensor's estimations of individual urination events (i.e., urine volume). We fitted 15 Holstein-Friesian × Jersey lactating dairy cows (506 ± 35 kg of live weight, body condition score of 3.75 ± 0.25, and 150.4 ± 20.7 d in milk) with individual PEETER V1.0 sensors and placed them in metabolism crates for 72 h. Every urination event (n = 480) was collected manually and compared with the urine volume estimated by the PEETER V1.0 sensor to determine precision and accuracy using Lin's concordance correlation coefficient (CCC). The CCC is calculated as a function of the Pearson's correlation (precision) and bias correction factor (C_b; C_b = 1 is perfect), and it demonstrates how far the values of the 2 methods are from perfect agreement (accuracy; i.e., a 45° line). The mean urination event volume (mean ± standard deviation) was 2.7 ± 0.94 and 2.6 ± 0.92 L for the actual and PEETER V1.0 sensor, respectively. The PEETER V1.0 sensor showed excellent precision (r = 0.90) with near-perfect accuracy (C_b = 1.00), and the CCC value was high (CCC = 0.90), indicating excellent agreement. Based on these results, the PEETER V1.0 urine sensor provides estimates that are precise and accurate. We conclude that the PEETER V1.0 sensor can be used to evaluate urination behavior of grazing dairy cows.

Grazing dairy cows with low milk urea nitrogen breeding values excrete less urinary urea nitrogen

There is an increasing pressure on temperate pastoral dairy production systems to reduce environmental impacts, coming from the inefficient use of N by cows in the form of excessive urinary N excretion and subsequent N leaching to the waterways and NO₂ emissions to the atmosphere, these impacts have spurred research into various mitigation strategies, which have so far overlooked animal-based solutions. The objectives of this study were first, to investigate the relationship between MUN breeding values (MUNBV) and urinary urea N (UUN) concentrations and total excretion in grazing dairy cows; and secondly, to evaluate such a potential relationship in the context of different sward compositions and stage of lactation. Forty-eight multiparous, lactating Holstein-Friesian dairy cows genetically divergent for MUNBV were strip-grazed on either a ryegrass-white clover (24 cows) or ryegrass, white clover and plantain sward (24 cows), during both early and late lactation. Cows were fitted with Lincoln University PEETER sensors to evaluate urination behaviour by measuring frequency and volume of urination, as well as daily urine excretion. Urine and faeces were sampled for urea N content. Milk yield and composition were measured for individual cows in both periods. There was a positive relationship between MUNBV and MUN (R² = 0.67, P ≤ 0.05), with MUN decreasing 1.61 ± 0.19 mg/dL per unit decrease in MUNBV across both sward types and stages of lactation. Urinary urea N concentration decreased 0.67 ± 0.27 g/L (R² = 0.46, P ≤ 0.05) per unit decrease of MUNBV, with no effect on urine volume or frequency (number of urination events per day), which resulted in a 165.3 g/d difference in UUN excretion between the animal with the highest and the lowest MUNBV. At the same milk yield, percentage of protein in milk increased by 0.09 ± 0.03 (R² = 0.61, P ≤ 0.05,) per unit decrease in MUNBV. Our results suggest that breeding and selecting for dairy cows with low MUNBV can reduce urinary urea N deposition onto pasture and consequently the negative environmental impact of pastoral dairy production systems in temperate grasslands. Moreover, reducing MUNBV of dairy cows can potentially increase farm profitability due to greater partitioning of N to milk in the form of protein.

Evaluation of a pharmacist-led penicillin allergy de-labelling ward round: a novel antimicrobial stewardship intervention

BACKGROUND

Antibiotic allergy labels (AALs), reported by up to 25% of hospitalized patients, are a significant barrier to appropriate prescribing and a focus of antimicrobial stewardship (AMS) programmes.

METHODS

A prospective audit of a pharmacist-led AMS penicillin allergy de-labelling ward round at Austin Health (Melbourne, Australia) was evaluated. Eligible inpatients with a documented penicillin allergy receiving an antibiotic were identified via an electronic medical report and then reviewed by a pharmacist-led AMS team. The audit outcomes evaluated were: (i) AMS post-prescription review recommendations; (ii) direct de-labelling; (iii) inpatient oral rechallenge referral; (iv) skin prick testing/intradermal testing referral; and (v) outpatient antibiotic allergy clinic assessment.

RESULTS

Across a 5 month period, 106 patients were identified from a real-time electronic prescribing antibiotic allergy report. The highest rate of penicillin allergy de-labelling was demonstrated in patients who were referred for an inpatient oral rechallenge with 95.2% (n = 21) successfully having their penicillin AAL removed. From the 22 patients with Type A reactions, 63.6% had their penicillin AAL removed. We demonstrated a significant decrease in the prescribing of restricted antibiotics (defined as third- or fourth-generation cephalosporins, fluoroquinolones, glycopeptides, carbapenems, piperacillin/tazobactam, lincosamides, linezolid or daptomycin) in patients reviewed (pre 42.5% versus post 17.9%, P = 0.0002).

CONCLUSIONS

A pharmacist-led AMS penicillin allergy de-labelling ward round reduced penicillin AALs and the prescribing of restricted antibiotics. This model could be implemented at other hospitals with existing AMS programmes.

Changing trends in surgery for abdominal Crohn's disease

AIM

The introduction of biological agents and laparoscopy are, arguably, the most important developments for the treatment of Crohn's disease (CD) in the last two decades. Due to the efficacy of biological agents in treating mild disease, it is likely that the percentage of surgery for complex cases may have increased. The objective of this study was to analyse the changing characteristics and results of the surgical treatment of patients with CD over the past 13 years.

METHODS

All patients who underwent abdominal surgery for CD between 2004 and 2016 were retrospectively identified. Data were compared between two periods (2004-2010 and 2011-2016).

RESULTS

A total of 908 procedures were performed (48% men, mean age 43 ± 16 years). Demographic and CD characteristics changed significantly over time: comorbidities were more frequent (35% vs 46%, P < 0.0001), and preoperative steroids (28% vs 36%, P < 0.01) and anti-tumour necrosis factor (20% vs 40%, P < 0.0001) treatments were more frequently used in the second period. Smoking (14% vs 8%, P < 0.0001) and use of immunosuppressors (32% vs 22%, P < 0.001) decreased significantly. More cases of penetrating disease (22% vs 32%, P < 0.001) were operated upon in the second period. The laparoscopic approach (49% vs 57%, P < 0.04) was more frequently performed and mean blood loss (167 ± 222 vs 123 ± 243 ml, P < 0.01) decreased significantly. Postoperative morbidity did not change between the two periods.

CONCLUSION

Despite a higher incidence of comorbidities and the use of biologics postoperative morbidity remained unchanged. An increased use of laparoscopy and a decreased intra-operative blood loss may have contributed to offsetting the impact of increased comorbidity.

Relatively normal human lymphopoiesis but rapid turnover of newly formed B cells in transplanted nonobese diabetic/SCID mice

Human B lineage lymphocyte precursors in chimeric nonobese diabetic/SCID mice transplanted with umbilical cord blood cells were directly compared with those present in normal bone marrow. All precursor subsets were represented and in nearly normal proportions. Cell cycle activity and population dynamics were investigated by staining for the Ki-67 nuclear Ag as well as by incorporation experiments using 5-bromo-2'-deoxyuridine. Again, this revealed that human B lymphopoiesis in chimeras parallels that in normal marrow with respect to replication and progression through the lineage. Moreover, sequencing of Ig gene rearrangement products showed that a diverse repertoire of V(H) genes was utilized by the newly formed lymphocytes but there was no evidence for somatic hypermutation. The newly formed B cells frequently acquired the CD5 Ag and had a short life span in the periphery. Thus, all molecular requirements for normal B lymphocyte formation are present in nonobese diabetic/SCID mice, but additional factors are needed for recruitment of B cells into a fully mature, long-lived pool. The model can now be exploited to learn about species restricted and conserved environmental cues for human B lymphocyte production.

Intraaortic balloon pumping through the common iliac artery: management of the ambulatory intraaortic balloon pump patient

Indications for use of the intraaortic balloon pump have expanded as advances in the treatment of heart disease have continued. The intraaortic balloon pump is the most widely used circulatory assist device inserted as short term or long term therapy. Because the percutaneous femoral artery approach requires bedrest, new techniques for intraaortic balloon pump insertion that allow greater mobility are being developed for patients who require long term ventricular support. The goal of ambulation in these patients is to prevent potential complications associated with prolonged immobility. This paper reviews the use of the common iliac artery as an alternate site for intraaortic balloon pump insertion that allows the patient to ambulate and exercise. Pre and post procedure management as well as potential complications of intraaortic balloon pump insertion are discussed.

Features of sexually transmitted disease services important to African American adolescents

OBJECTIVE

To determine the relative importance of various features of health clinics when African American adolescents consider seeking care for sexually transmitted diseases (STDs).

DESIGN

Confidential interviewer-administered telephone survey.

SETTING

A predominantly low-income, African American neighborhood in San Francisco, Calif.

PARTICIPANTS

Random sample of African American adolescents aged 12 to 17 years; 302 (76.6%) of 394 identified eligible adolescents participated.

MAIN OUTCOME MEASURES

Items and scales measuring adolescents' sense of the importance of the attributes of the provider (alpha = .58), availability of services (alpha = .61), and perceived confidentiality of health services from family (alpha = . 72) when deciding where to seek care for possible STDs.

RESULTS

More than 90% (90.4%) of subjects rated items relating to provider attributes as being highly important when they consider where they would seek care for an STD; between 62.5% and 82.7% rated availability items as being highly important; and between 38.6% and 60.8% rated items pertaining to confidentiality as being highly important. Greater importance was placed on provider attributes and confidentiality by female than male adolescents. The importance placed on provider attributes and confidentiality increased as adolescents aged.

CONCLUSIONS

Low-income, African American adolescents place great importance on provider attributes, less importance on availability, and even less importance on confidentiality when deciding where to seek health care for a possible STD. Health care providers and organizations need to be aware of these adolescent preferences to better promote screening and treatment of STDs in this population.

Dystrophy and myogenesis in mdx diaphragm muscle

In order to determine why the diaphragm is more severely affected by progressive dystrophy than limb muscles in the mdx mouse, we examined how regional variations in diaphragm dystrophy, the measures of disease and repair, proliferation by committed myogenic cells, and the expression of mitogenic basic fibroblast growth factor (bFGF) could contribute to muscle-specific disease phenotypes. There were regional variations in new myotube formation in the diaphragm, with disease more severe in crural than costal leaflets. New repair increased in hyperthyroidism without changes in accumulated repair, probably due to fiber loss. General proliferation was nearly twofold higher in limb than diaphragm mononuclear cells. Since only 2.5-8.4% of committed muscle precursors were proliferating, the higher proliferation by myf5+ myogenic cells in diaphragm did not account for muscle-specific differences. Proliferation by bFGF+ mononuclear cells and an immunogold labeling index for bFGF protein in diaphragm myoblasts were lower in diaphragm than limb muscle. In culture, mixed limb myoblast and fibroblasts contained more S phase cells than diaphragm cells, although myoblasts cycled similarly between muscles. Therefore while muscle architecture and the formation and number of new myotubes certainly affect disease phenotype, the differential outcome of regeneration in mdx diaphragm and limb muscle appears to be contributed by both nonmyogenic and myogenic cells.

MyoD is required for myogenic stem cell function in adult skeletal muscle

To investigate the function of MyoD in adult skeletal muscle, we interbred MyoD mutant mice with mdx mice, a model for Duchenne and Becker muscular dystrophy. Mice lacking both MyoD and dystrophin displayed a marked increase in severity of myopathy leading to premature death, suggesting a role for MyoD in muscle regeneration. Examination of MyoD mutant muscle revealed elevated numbers of myogenic cells; however, myoblasts derived from these cells displayed normal differentiation potential in vitro. Following injury, MyoD mutant muscle was severely deficient in regenerative ability, and we observed a striking reduction in the in vivo proliferation of myogenic cells during regeneration. Therefore, we propose that the failure of MyoD-deficient muscle to regenerate efficiently is not caused by a reduction in numbers of satellite cells, the stem cells of adult skeletal muscle, but results from an increased propensity for stem-cell self-renewal rather than progression through the myogenic program.

Thrombin activity on dissected and anastomosed human arteries

The mechanism of anastomotic thrombosis in microvascular surgery remains poorly understood. We hypothesized that thrombin activity at anastomoses plays a major role in this process. To study this, a surgically relevant human artery anastomosis model was used to (i) measure surface thrombin activity on anastomoses and on intact vessel, (ii) determine the inhibitability of surface thrombin by heparin and recombinant hirudin (r-hirudin), and (iii) determine the anastomotic and intact vessel binding capacity for additional thrombin. Human placental artery segments were placed in chambers in which 0.2 cm2 of luminal surface was exposed to citrated platelet-poor plasma for 10 min at 37 degrees C. The fibrinopeptide A (FPA) concentration (indicating the action of thrombin on fibrinogen) in the supernatant was then measured using an ELISA assay. Intact vessels and anastomoses expressed equivalent thrombin activity that could not be inhibited by heparin at a concentration (0.3 U/ml) that is sufficient to prolong the activated partial thromboplastin time two-fold. Conversely, the concentration of heparin routinely used in intraoperative vessel irrigation solutions (50 U/ml) was able to completely block thrombin activity at both sites. r-Hirudin (0.3 heparin equivalent anti-IIa U/ml) was able to inhibit nearly all of the thrombin activity on each site. Each site was able to bind and express the activity of additional thrombin, indicating the potential for increased vessel thrombogenicity after local clot has formed and has been removed. These data indicate the presence of thrombin on dissected human vessels and its presence in equal amounts on intact and anastomosed vessels when measurement is made before blood flow resumes. Furthermore, vessel-associated thrombin is resistant to a standard systemic concentration of heparin but is susceptible to the much higher heparin concentration that can be delivered locally by the surgeon during vessel irrigation.

Pathogenesis of pulmonary aspergillosis. Granulocytopenia versus cyclosporine and methylprednisolone-induced immunosuppression

Patients with chemotherapy-induced granulocytopenia for neoplastic diseases and those receiving cyclosporin A plus corticosteroids for prevention and treatment of organ transplant rejection are two immunologically distinct patient populations with high risks for development of invasive pulmonary aspergillosis. In order to compare the pathogenesis of aspergillosis in these two high-risk populations and to further characterize the role of cyclosporin A in development of pulmonary aspergillosis, we studied the patterns of infection and inflammation in two clinically applicable rabbit models of invasive pulmonary aspergillosis. There were striking differences in the patterns of infection and inflammation of invasive pulmonary aspergillosis according to the type of underlying immune defect. Among rabbits challenged with the same intratracheal inoculum, there was a 100% mortality for invasive pulmonary aspergillosis in profoundly granulocytopenic rabbits in comparison with a 100% mortality for invasive pulmonary aspergillosis in profoundly granulocytopenic rabbits in comparison with a 100% survival in rabbits immunosuppressed with cyclosporin A plus methylprednisolone (CsA+MP). Lesions of pulmonary aspergillosis in granulocytopenic rabbits consisted predominantly of coagulative necrosis, intraalveolar hemorrhage, and scant mononuclear inflammatory infiltrate. By comparison, pulmonary foci in rabbits immunosuppressed by CsA+MP consisted mainly of neutrophilic and monocytic infiltrates, inflammatory necrosis, and scant intraalveolar hemorrhage. There was extensive infiltration by hyphae with angioinvasion in granulocytopenic rabbits, whereas conidia in various stages of germination predominated in CsA+MP treated animals in which there was a paucity of hyphae or angioinvasion. Extrapulmonary disease predominated in granulocytopenic rabbits. Methylprednisolone was the major immunosuppressive drug in rabbits treated with CsA+MP. Cyclosporin A alone did not increase the progression of pulmonary aspergillosis and did so only when used chronically with methylprednisolone.

Therapeutic monitoring of experimental invasive pulmonary aspergillosis by ultrafast computerized tomography, a novel, noninvasive method for measuring responses to antifungal therapy

Pulmonary infiltrates in neutropenic hosts with invasive aspergillosis are due to vascular invasion and hemorrhagic infarction. In order to measure the effect of antifungal compounds on this organism-mediated tissue injury, we monitored the course of pulmonary infiltrates by serial ultrafast computerized tomography (UFCT) in persistently granulocytopenic rabbits with experimental invasive pulmonary aspergillosis. The course of pulmonary lesions measured by serial UFCT scans was compared with those measured by conventional chest radiography, histopathological resolution of lesions, and microbiological clearance of Aspergillus fumigatus. Treatment groups included either amphotericin B colloidal dispersion in dosages of 1, 5, and 10 mg/kg of body weight per day intravenously or conventional desoxycholate amphotericin B at 1 mg/kg/day intravenously. Therapeutic monitoring of pulmonary lesions by UFCT demonstrated a significant dose-response relationship. Lesions continued to progress in untreated controls, whereas lesions in treated rabbits initially increased and then decreased in response to antifungal therapy in a dosage-dependent manner (P < or = 0.05 to P < or = 0.005, depending upon the groups compared). This same trend of resolution of lesions in response to antifungal therapy was also demonstrated by postmortem examination and by microbiological clearance of the organism. These data indicated that amphotericin B colloidal dispersion at 5 and 10 mg/kg/day exerted a more rapid rate of clearance of lesions than conventional amphotericin B. UFCT was more sensitive than conventional chest radiography in detecting lesions due to invasive pulmonary aspergillosis (P < 0.05 to P < 0.005, depending upon the groups compared). These findings establish a correlation among UFCT-defined lesions, microbiological response, and resolution of pathologically defined lesions in experimental invasive pulmonary aspergillosis. Serial monitoring of UFCT-defined lesions of aspergillosis provides a novel system for determining the antifungal response of organism-mediated tissue injury.

A new photopolymerizable blood vessel glue that seals human vessel anastomoses without augmenting thrombogenicity

A new nonbiologic photopolymerizable glue, polyethyleneglycol 400 diacrylate, was studied with respect to its mechanical and biochemical interaction with human blood vessels. Using the human placental artery model, we tested the ability of polyethyleneglycol 400 diacrylate to prevent leakage of blood at the site of vascular anastomoses, which are made porous by the presence of tissue gaps and suture puncture sites. Fibrin glue is known to augment local vessel thrombogenicity through the presence of the coagulation enzyme thrombin. We tested the effect of externally applied polyethyleneglycol 400 diacrylate (which does not contain thrombin) on luminal thrombin activity and platelet deposition from flowing human blood. At a shear rate of 312 per second and a transmural pressure of 80 cm H2O, the leakage rate of saline from human placental artery anastomoses was 1.0 +/- 1.2 ml/min (n = 8). When the same anastomoses were then glued, 7 of 8 of the anastomoses leaked less than 0.05 ml/min (p < 0.05). Platelet deposition to human vessels was not influenced by the external application of polyethyleneglycol 400 diacrylate either on intact vessels (no polyethyleneglycol 400 diacrylate, 0.51 +/- 0.28 x 10(6) platelets/cm2; with polyethyleneglycol 400 diacrylate, 0.47 +/- 0.26 x 10(6) platelets/cm2; n = 7) or at anastomoses (no polyethyleneglycol 400 diacrylate, 0.69 +/- 0.36 x 10(6) platelets/cm2; with polyethyleneglycol 400 diacrylate, 0.53 +/- 0.33 x 10(6) platelets/cm2; n = 8), p > 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

HIV infection in homosexual and bisexual men 18 to 29 years of age: the San Francisco Young Men's Health Study

OBJECTIVES

Recent studies suggest very high human immunodeficiency virus (HIV) infection rates in some populations of younger homosexual men, but these studies may represent only particularly high-risk populations. The current study obtained population-based data on the HIV epidemic in young homosexual/bisexual men.

METHODS

A household survey of unmarried men 18 through 29 years of age involved a multistage probability sample of addresses in San Francisco. A follow-up interview and HIV test for men who were HIV negative at baseline were completed; the median follow-up was 8.9 months.

RESULTS

Sixty-eight of 380 homosexual/bisexual men (17.9%) tested HIV seropositive. Sixty-three percent of men reported one or more receptive anal intercourse partners in the previous 12 months, and 41% of those men did not use condoms consistently. The HIV seroincidence rate among those seronegative at first study was 2.6% per year.

CONCLUSIONS

HIV infection rates in young homosexual men in San Francisco are lower than those in the early 1980s; however, the rate of infection in these men, most of whom became sexually active after awareness of AIDS had become widespread, threatens to continue the epidemic in the younger generation at a level not far below that of a decade ago.

Itraconazole for experimental pulmonary aspergillosis: comparison with amphotericin B, interaction with cyclosporin A, and correlation between therapeutic response and itraconazole concentrations in plasma

Itraconazole and amphotericin B were compared by using a newly developed model of invasive pulmonary aspergillosis in rabbits immunosuppressed with methylprednisolone and cyclosporin A (CsA). Both itraconazole at 40 mg/kg (given orally) and amphotericin B at 1 mg/kg (given intravenously) had in vivo antifungal activity in comparison with controls. At these dosages, amphotericin B was more effective than itraconazole in reducing the tissue burden (log10 CFU per gram) of Aspergillus fumigatus (P < 0.05) and the number of pulmonary lesions (P < 0.01). However, there was considerable variation in the near-peak concentrations of itraconazole in plasma (median, 4.15 micrograms/ml; range, < 0.5 to 16.8 micrograms/ml) and a strong inverse correlation between concentrations of itraconazole in plasma and the tissue burden of A. fumigatus. An inhibitory sigmoid maximum-effect model predicted a significant pharmacodynamic relationship (r = 0.87, P < 0.001) between itraconazole concentrations in plasma and antifungal activity as a function of the tissue burden of A. fumigatus. This model demonstrated that levels in plasma of greater than 6 micrograms/ml were associated with a significantly greater antifungal effect. Levels in plasma of less than 6 micrograms/ml were associated with a rapid decline in the antifungal effect. Itraconazole, in comparison with amphotericin B, caused a twofold elevation of CsA levels (P < 0.01) but was less nephrotoxic (P < 0.01). This study of experimental pulmonary aspergillosis demonstrated that amphotericin B at 1 mg/kg/day was more active but more nephrotoxic than itraconazole at 40 mg/kg/day, that itraconazole increased concentrations of CsA in plasma, and that the antifungal activity of itraconazole strongly correlated with concentrations in plasma in an inhibitory sigmoid maximum-effect model. These findings further indicate the importance of monitoring concentrations of itraconazole in plasma as a guide to increasing dosage, improving bioavailability, and optimizing antifungal efficacy in the treatment of invasive pulmonary aspergillosis.

Dose-dependent antifungal activity and nephrotoxicity of amphotericin B colloidal dispersion in experimental pulmonary aspergillosis

We investigated the safety and efficacy of amphotericin B colloidal dispersion (ABCD) for the treatment of invasive pulmonary aspergillosis in persistently granulocytopenic rabbits. Treatment groups included ABCD in dosages of 1, 5, and 10 mg/kg/day intravenously or conventional desoxycholate amphotericin B (DAmB) at 1 mg/kg/day intravenously. Antifungal activity was directly related to increasing dosage of ABCD as determined by the concentration of Aspergillus fumigatus organisms in lungs and the frequency of hemorrhagic pulmonary lesions. At 5 and 10 mg/kg/day, there was a significant reduction in the tissue burden of A. fumigatus as measured by percent culture-positive lobes and CFU per gram of tissue (P < or = 0.001), whereas at 1 mg/kg/day measured by percent culture-positive lobes and CFU per gram of tissue (P < or = 0.001), whereas at 1 mg/kg/day the tissue burden of A. fumigatus was not significantly different from that in untreated controls. Microbiological clearance was significantly greater at 1 mg of DAmB per kg per day than at 1 mg of ABCD per kg per day (P < or = 0.001). There was no difference in microbiological clearance of bronchoalveolar lavage fluid among the treatment groups as measured by CFU per milliliter. As determined by survival, ABCD at 5.0 mg/kg/day was more effective than DAmB at 1.0 mg/kg/day and ABCD at 10 mg/kg/day. ABCD at 10 mg/kg/day was more nephrotoxic than the lower dosages of ABCD and resulted in higher mortality. Impairment of glomerular filtration developed as a direct function increasing the ABCD dosage (r = 0.77; P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral blood flow changes with acute cocaine intoxication: clinical correlations with SPECT, CT, and MRI

In summary, these data suggest that widespread primary or secondary cerebral vasoconstriction is common in patients with neurological complications from cocaine. In most patients, SPECT showed wide-spread hypoperfusion in regions that had no clear clinical significance (e.g., the periventricular area). In many, the SPECT was performed more than 24 hours after the onset of neurological symptomatology. These findings raise several questions. It has been assumed that these SPECT changes in patients with acute neurological symptoms are temporary, although it will be important to determine whether these areas of hypoperfusion persist after symptoms have abated. Recently, Holman and colleagues (1991) found multifocal and deep areas of hypoperfusion with SPECT in 16 of 18 patients with a history of chronic cocaine abuse. Although most of the subjects tested positive for cocaine, several had abstained from cocaine use for weeks prior to the study. All 18 subjects had neuropsychological deficits, 13 mild and 5 moderate. Similarly, Pascual-Leone and colleagues (1991) have shown that CT scan atrophy strongly correlates with the duration of cocaine abuse, suggesting that brain injury may occur with continued use of cocaine. It is the authors' concern that cocaine abuse might produce permanent changes in cerebral perfusion. In conclusion, brain SPECT was found to be a useful procedure in the evaluation of acute cocaine intoxication. Brain SPECT revealed focal cortical lesions not seen on head CT or MRI, which corresponded to clinical deficits. In addition, [99mTc]HMPAO brain SPECT had a characteristic scalloped appearance, and this may be a marker for acute intoxication with cocaine. This study further supports the contention that cocaine causes neurological disease by its vasoconstrictive action.

Risk for AIDS in multiethnic neighborhoods in San Francisco, California. The population-based AMEN Study

To examine the actual and potential spread of human immunodeficiency virus (HIV) from an acquired immunodeficiency syndrome (AIDS) epicenter to surrounding neighborhoods, we studied the prevalence of the viral infection and AIDS risk behaviors from 1988 to 1989 in a representative sample of unmarried whites, African Americans, and Hispanics living in San Francisco. We surveyed 1,770 single men and women aged 20 to 44 years (a 64% response rate) in a random household sample drawn from 3 neighborhoods of varying geographic and cultural proximity to the Castro District where the San Francisco epidemic began. Of 1,369 with blood tests, 69 (5%) had HIV antibodies; all but 5 of these reported either homosexual activity (32% HIV-positive; 95% confidence interval [CI] = 23%, 41%), injection drug use (5% HIV-positive; CI = 1%, 14%), or both (59% HIV-positive; CI 42%, 74%). Homosexual activity was more common among white men than among African-American or Hispanic men, but the proportion of those infected was similar in the 3 races. Both the prevalence of homosexually active men and the proportion infected were much lower in the 2 more outlying neighborhoods. Risk behaviors in the past year for acquiring HIV heterosexually--sex with an HIV-infected person or homosexually active man or injection drug user, unprotected sexual intercourse with more than 4 partners, and (as a proxy) having a sexually transmitted disease--were assessed in 1,573 neighborhood residents who were themselves neither homosexually active men nor injection drug users. The prevalence of reporting at least 1 of these risk behaviors was 12% overall, and race-gender estimates ranged from 5% among Hispanic women to 21% among white women. We conclude that in San Francisco, infection with HIV is rare among people who are neither homosexually active nor injection drug users, but the potential for the use spread of infection is substantial, as 12% of this group reported important risk behaviors for acquiring the virus heterosexually.

An analysis of cerebral blood flow in acute closed-head injury using technetium-99m-HMPAO SPECT and computed tomography

Technetium-99m-hexamethylpropyleneamine (HMPAO) SPECT and x-ray CT were compared in 15 patients with acute closed-head injury. There were 44 focal lesions in all. Fifteen (34%) lesions were seen on both x-ray and SPECT. Seventeen (39%) lesions were seen only on SPECT. Twelve (27%) of the lesions were seen on x-ray tomography only. Of the lesions seen on x-ray tomography but not on SPECT, two were subarachnoid hemorrhage, two were thin subdural hematomas, and eight were contusions. This study shows that SPECT can detect focal disturbances of cerebral blood flow that are not seen on x-ray tomography. It also suggests that there are two types of contusions: those with a decreased cerebral blood flow (i.e., detectable on SPECT) and those with a cerebral blood flow equal to that of the surrounding brain.

Acetylcholine formation from glucose following acute choline supplementation

The effects of choline administration on acetylcholine metabolism in the central nervous system are controversial. Although choline supplementation may elevate acetylcholine (ACh) content in brain, turnover studies with labelled choline precursors suggest that systemic choline administration either has no effect or actually diminishes brain ACh synthesis. Since choline supplementation elevates brain choline levels, the apparent decreases in previous turnover studies may reflect dilution of the labelled choline precursor pool rather than altered ACh formation. Therefore, brain ACh formation from [U-14C]glucose was determined after choline supplementation. A two to three fold elevation of brain choline did not alter ACh levels or [U-14C]glucose incorporation into ACh in the cortex, hippocampus or striatum. Although atropine stimulated ACh formation from [U-14C]glucose in hippocampus, two to three fold increases in brain choline did not augment ACh synthesis or content in atropine pretreated animals. Atropine depressed brain regional glucose utilization and this effect was not reversed by choline treatment. These results suggest that short-term elevation of brain choline does not enhance ACh formation from [U-14C]glucose, and argue against enhanced presynaptic cholinergic function after acute, systemic choline administration.

Comparison of N-acyl phosphatidylethanolamines with different N-acyl groups as activators of glucocerebrosidase in various forms of Gaucher's disease

The acidic phospholipid requirement of the predominant particulate beta-glucosidase of mammalian spleen and liver was investigated using a series of N-acyl derivatives of dioleoyl phosphatidylethanolamine (PE). The PE, a neutral phospholipid, was converted to an acidic lipid, (N-acyl)-phosphatidylethanolamine (NAPE) by acylation of the amino group with different fatty acyl chains. Lysosomal beta-glucosidases from rat liver and spleens of controls and patients with various types of Gaucher's disease were solubilized and delipidated by extraction with sodium cholate and 1-butanol. All members of the NAPE series tested were effective activators of the delipidated rat liver beta-glucosidase, and the stimulatory power of the NAPE family increased with increasing chain length of the fatty acid substitution. In contrast, dioleoyl-PE had no effect on beta-glucosidase activity. A heat-stable factor (HSF) purified from the spleen of a patient with Gaucher's disease significantly increased the sensitivity of the rat liver beta-glucosidase to all of the NAPE derivatives. The maximum stimulation achieved in the presence of HSF was independent of N-acyl chain length. Compared to the potent activator, phosphatidylserine (PS), (N-acetyl)-PE and (N-linoleoyl)-PE were half as effective as activators of beta-glucosidase from control human spleen. PS stimulated the beta-glucosidase of type 1 nonneurologic Gaucher's disease, but none of the NAPE compounds activated it. Neither PS nor any of the (N-acyl)-PE compounds could activate a delipidated preparation of beta-glucosidase obtained from the spleen of a neurologic case. These results indicate that although the presence of a net negative charge on a phospholipid confers upon it an ability to reconstitute beta-glucosidase activity to the normal, nonmutant enzyme, it is insufficient to permit differentiation of the various types of Gaucher's disease.