Tackle Technique and Changes in Playerload™ During a Simulated Tackle: An Exploratory Study

In collision sports, the tackle has the highest injury incidence, and is key to a successful performance. Although the contact load of players has been measured using microtechnology, this has not been related to tackle technique. The aim of this study was to explore how PlayerLoad™ changes between different levels of tackling technique during a simulated tackle. Nineteen rugby union players performed twelve tackles on a tackle contact simulator (n = 228 tackles). Each tackle was recorded with a video-camera and each player wore a Catapult OptimEyeS5. Tackles were analysed using tackler proficiency criteria and split into three categories: Low scoring(≤5 Arbitrary units (AU), medium scoring(6 and 7AU) and high scoring tackles(≥8AU). High scoring tackles recorded a higher PlayerLoad™ at tackle completion. The PlayerLoad™ trace was also less variable in the high scoring tackles. The variability in the PlayerLoad™ trace may be a consequence of players not shortening their steps before contact. This reduced their ability to control their movement during the contact and post-contact phase of the tackle and increased the variability. Using the PlayerLoad™ trace in conjunction with subjective technique assessments offers coaches and practitioners insight into the physical-technical relationship of each tackle to optimise tackle skill training and match preparation.

Patient Burden with Current Surveillance Paradigm and Factors Associated with Interest in Altered Surveillance for Early Stage HPV-Related Oropharyngeal Cancer

INTRODUCTION

Optimal surveillance paradigms for survivors of early stage human papillomavirus (HPV)-related oropharyngeal cancer are not well defined. This study aimed to characterize patient interest in and factors associated with an altered surveillance paradigm.

MATERIALS AND METHODS

We surveyed patients with Stage I or II HPV-related oropharyngeal cancer treated at a tertiary care institution from 2016 to 2019. Primary outcomes were descriptive assessment of patient knowledge, interest in altered surveillance, burdens of in-person appointments, and priorities for surveillance visits. Ordinal regression was used to identify correlates of interest in altered surveillance.

RESULTS

Sixty-seven patients completed surveys from February to April 2020 at a median of 21 months since completing definitive treatment. A majority (61%) of patients were interested in a surveillance approach that decreased in-person clinic visits. Patients who self-identified as medical maximizers, had higher worry of cancer recurrence, or were in long-term relationships were less likely to be interested. Patients reported significant burdens associated with surveillance visits, including driving distance, time off work, and nonmedical costs. Patients were most concerned with discussing cancer recurrence (76%), physical quality of life (70%), mortality (61%), and mental quality of life (52%) with their providers at follow-up visits.

CONCLUSION

Patients with early stage HPV-related oropharyngeal cancers are interested in altered surveillance approaches, experience significant burdens related to surveillance visits, and have concerns that are not well addressed with current surveillance approaches, including physical and mental quality of life. Optimized surveillance approaches should incorporate patient priorities and minimize associated burdens.

IMPLICATIONS FOR PRACTICE

The number of patients with HPV-related oropharyngeal cancers is increasing, and numerous clinical trials are investigating novel approaches to treating these good-prognosis patients. There has been limited work assessing optimal surveillance paradigms in these patients. Patients experience significant appointment-related burdens and have concerns such as physical and mental quality of life. Additionally, patients with early stage HPV-related oropharyngeal cancers express interest in altered surveillance approaches that decrease in-person clinic visits. Optimization of surveillance paradigms to promote broader survivorship care in clinical practice is needed.

Tackle injury epidemiology and performance in rugby league - narrative synthesis

Background

In rugby league (RL), the ability to repeatedly engage in the tackle, whether as a ball carrier or tackler, is essential for team success and player performance. It is also the leading cause of injury, with over 90% of total injuries occurring during the tackle in professional and amateur cohorts. To effectively reduce the risk of injury and optimise performance, establishing the extent of the 'problem', through injury surveillance or descriptive performance studies is required.

Objective

The purpose of this narrative synthesis was to systematically search and synthesise tackle injury epidemiology and tackle performance frequency in RL. To achieve this objective, a systematic review was conducted.

Methods

The search was limited to English-only articles published between January 1995 and October 2018. Based on the search criteria, a total of 53 studies were found: 32 focused on tackle injury epidemiology (nine cases studies) and 21 focused on tackle frequency.

Results

In general, over 600 tackles may occur during an RL match. Tackle injury frequencies (both overall and time-loss injuries) ranged between 47%-94% at the professional level, and between 38%-96% for the lower levels of play. A greater proportion of injuries occurring in professional RL are severe time-loss injuries when compared to lower levels of play. Most time-loss and overall injuries occur to players who are tackled, i.e., ball carriers, across all levels of play.

Conclusion

This narrative synthesis will facilitate tackle injury prevention and performance research in RL, and act as a reference document for coaches and practitioners.

Lay of the land: narrative synthesis of tackle research in rugby union and rugby sevens

Objectives

The purpose of this review was to synthesise both injury prevention and performance tackle-related research to provide rugby stakeholders with information on tackle injury epidemiology, including tackle injury risk factors and performance determinants, and to discuss potential preventative measures.

Design

Systematic review and narrative synthesis.

Data sources

PubMed, Scopus and Web of Science.

Eligibility criteria

Limited to peer-reviewed English-only publications between January 1995 and October 2018.

Results

A total of 317 studies were identified, with 177 in rugby union and 13 were in rugby sevens. The tackle accounted for more than 50% of all injuries in rugby union and rugby sevens, both at the professional level and at the lower levels, with the rate of tackle injuries higher at the professional level (mean 32/1000 player-hours) compared with the lower levels (mean 17/1000 player-hours). A player’s tackle actions and technical ability were identified as major risk factors for injury and a key determinant of performance.

Summary/conclusion

Evidence-based education, progressive tackle technique training with a high potential to transfer and law changes have been proposed as key modifiers of player tackle actions and technical ability. Conceivably, all three modifiers working in unison (as opposed to separately) will have a higher potential at reducing tackle injury risk while enhancing performance. With the guidance of tackle injury and performance studies, as well as stakeholder engagement, experiential and explorative tackle research has the potential to inspire innovative injury prevention and performance strategies.

Consensus on a video analysis framework of descriptors and definitions by the Rugby Union Video Analysis Consensus group

Using an expert consensus-based approach, a rugby union Video Analysis Consensus (RUVAC) group was formed to develop a framework for video analysis research in rugby union. The aim of the framework is to improve the consistency of video analysis work in rugby union and help enhance the overall quality of future research in the sport. To reach consensus, a systematic review and Delphi method study design was used. After a systematic search of the literature, 17 articles were used to develop the final framework that described and defined key actions and events in rugby union (rugby). Thereafter, a group of researchers and practitioners with experience and expertise in rugby video analysis formed the RUVAC group. Each member of the group examined the framework of descriptors and definitions and rated their level of agreement on a 5-point agreement Likert scale (1:strongly disagree; 2:disagree; 3:neither agree or disagree; 4:agree; 5: strongly agree). The mean rating of agreement on the five-point scale (1:strongly disagree; 5:strongly agree) was 4.6 (4.3–4.9), 4.6 (4.4–4.9), 4.7 (4.5–4.9), 4.8 (4.6–5.0) and 4.8 (4.6–5.0) for the tackle, ruck, scrum, line-out and maul, respectively. The RUVAC group recommends using this consensus as the starting framework when conducting rugby video analysis research. Which variables to use (if not all) depends on the objectives of the study. Furthermore, the intention of this consensus is to help integrate video data with other data (eg, injury surveillance).

Correction to: Protection against cardiac ischemia-reperfusion injury by hypothermia and by inhibition of succinate accumulation and oxidation is additive

The original version of this article unfortunately contained a mistake.

Protection against cardiac ischemia-reperfusion injury by hypothermia and by inhibition of succinate accumulation and oxidation is additive

Hypothermia induced at the onset of ischemia is a potent experimental cardioprotective strategy for myocardial infarction. The aim of our study was to determine whether the beneficial effects of hypothermia may be due to decreasing mitochondria-mediated mechanisms of damage that contribute to the pathophysiology of ischemia/reperfusion injury. New Zealand male rabbits were submitted to 30 min of myocardial ischemia with hypothermia (32 °C) induced by total liquid ventilation (TLV). Hypothermia was applied during ischemia alone (TLV group), during ischemia and reperfusion (TLV-IR group) and normothermia (Control group). In all the cases, ischemia was performed by surgical ligation of the left anterior descending coronary artery and was followed by 3 h of reperfusion before assessment of infarct size. In a parallel study, male C57BL6/J mice underwent 30 min myocardial ischemia followed by reperfusion under either normothermia (37 °C) or conventionally induced hypothermia (32 °C). In both the models, the levels of the citric acid cycle intermediate succinate, mitochondrial complex I activity were assessed at various times. The benefit of hypothermia during ischemia on infarct size was compared to inhibition of succinate accumulation and oxidation by the complex II inhibitor malonate, applied as the pro-drug dimethyl malonate under either normothermic or hypothermic conditions. Hypothermia during ischemia was cardioprotective, even when followed by normothermic reperfusion. Hypothermia during ischemia only, or during both, ischemia and reperfusion, significantly reduced infarct size (2.8 ± 0.6%, 24.2 ± 3.0% and 49.6 ± 2.6% of the area at risk, for TLV-IR, TLV and Control groups, respectively). The significant reduction of infarct size by hypothermia was neither associated with a decrease in ischemic myocardial succinate accumulation, nor with a change in its rate of oxidation at reperfusion. Similarly, dimethyl malonate infusion and hypothermia during ischemia additively reduced infarct size (4.8 ± 2.2% of risk zone) as compared to either strategy alone. Hypothermic cardioprotection is neither dependent on the inhibition of succinate accumulation during ischemia, nor of its rapid oxidation at reperfusion. The additive effect of hypothermia and dimethyl malonate on infarct size shows that they are protective by distinct mechanisms and also suggests that combining these different therapeutic approaches could further protect against ischemia/reperfusion injury during acute myocardial infarction.

Assessing tackle performance using a novel collision sport simulator in comparison to a "live" one-on-one tackling drill

It is necessary to study the rugby tackle as it is associated with successful performance outcomes and is responsible for the majority of contact injuries. A novel collision sport simulator was developed to study tackle performance. The main aim of this validation study was to assess tackle technique performance between two different conditions: simulator versus a standardised one-on-one tackle drill previously used to assess technique. Tackling proficiency was assessed using a list of technical criteria. Mean scores, standard deviations and Cohen's d effect sizes were calculated. Mean overall score for dynamic i.e. running simulator tackles was 7.78 (95%CI 7.58-7.99) (out of 9) or 87% (standard deviation or SD±8.94), and mean overall score for dynamic "live" tackles was 7.85 (95%CI 7.57-8.13) (out of 9) or 87% (SD±9.60) (effect size = 0.08; trivial; p > 0.05). Mean overall score for static i.e. standing simulator tackles was 7.45 (95%CI 7.20-7.69) (out of 9) or 83% (SD±10.71), and mean overall score for static "live" tackles was 8.05 (95%CI 7.83-8.27) (out of 9) or 89% (SD±7.53) (effect size = 0.72; moderate; p < 0.001). The simulator replicates dynamic tackle technique comparable to real-life tackle drills. It may be used for research analysing various aspects of the tackle in rugby and other contact sports.

Facts and values: on the acceptability of risks in children's sport using the example of rugby - a narrative review

A clash of values has been identified between those who assert that:1. all childhood injuries, regardless of origin, are inherently undesirable and should be prevented and;2. those who believe that some measure of injury to children is an acceptable compromise for the physical benefits associated with physical activity and the development of abilities to appraise and deal with risks.A debate regarding whether the tackles and collisions permitted in schools' rugby represent acceptable risks, and what steps should be taken if they do not, exemplifies the issue.Questions regarding the magnitude of injury risks in sport are issues of fact and can be quantified via the results of injury surveillance studies. Risks are neither high nor low in isolation; they are relatively high or low with reference to other activities or across groups participating in an activity. Issues of the acceptability of a given degree of risk are value dependent. Research regarding perceptions of risk reveals wide variations in the degree of risk people view as acceptable. Factors impacting on risk perception include whether the risks are well known and understood, whether they are 'dread' risks and the degree to which people undertake the risks voluntarily and feel they have control over them.Based on the evidence currently available, the risks to children playing rugby do not appear to be inordinately high compared with those in a range of other childhood sports and activities, but better comparative information is urgently needed. Further evidence, however, should not necessarily be expected to result in the resolution of acceptable risk debates-pre-existing values shape our perspectives on whether new evidence is relevant, valid and reliable.

Mechanisms and Factors Associated With Tackle-Related Injuries in South African Youth Rugby Union Players

BACKGROUND

The majority of injuries in rugby union occur during tackle events. The mechanisms and causes of these injuries are well established in senior rugby union.

PURPOSE

To use information from an injury database and assess video footage of tackle-related injuries in youth rugby union matches to identify environmental factors and mechanisms that are potentially confounding to these injuries.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

Injury surveillance was conducted at the under-18 Craven Week rugby tournament. Tackle-related injury information was used to identify injury events in match video footage (role-matched noninjury tackle events were identified for the cohort of injured players). Events were coded using match situational variables (precontact, contact, and postcontact). Relative risk ratio (RRR; ratio of probability of an injury or noninjury outcome occurring when a characteristic was observed) was reported by use of logistic regression.

RESULTS

In comparison with the first quarter, injury risk was greater in the third (RRR = 9.75 [95% CI, 1.71-55.64]; P = .010) and fourth quarters (RRR = 6.97 [95% CI, 1.09-44.57]; P = .040) for ball carriers and in the fourth quarter (RRR = 9.63 [95% CI, 1.94-47.79]; P = .006) for tacklers. Ball carriers were less likely to be injured when they were aware of impending contact (RRR = 0.14 [95% CI, 0.03-0.66]; P = .012) or when they executed a moderate fend (hand-off) (RRR = 0.22 [95% CI, 0.06-0.84]; P = .026). Tacklers were less likely to be injured when performing shoulder tackles (same side as leading leg) in comparison to an arm-only tackle (RRR = 0.02 [95% CI, 0.001-0.79]; P = .037). Ball carriers (RRR = 0.09 [95% CI, 0.01-0.89]; P = .040) and tacklers (RRR = 0.02 [95% CI, 0.001-0.32]; P =.006) were less likely to be injured when initial contact was made with the tackler's shoulder/arm instead of his head/neck.

CONCLUSION

The relative risk of tackle-related injury was higher toward the end of matches. Incorrect technique may contribute to increased injury risk. Implementing recovery strategies between matches, training safe and effective techniques, and improving levels of conditioning may counter the negative effects of fatigue. These findings may assist stakeholders in youth rugby to formulate injury prevention strategies and may improve the preparation of field-side medical staff for managing tackle-related injuries at these or similar tournaments.

Video analysis of concussion injury mechanism in under-18 rugby

BACKGROUND

Understanding the mechanism of injury is necessary for the development of effective injury prevention strategies. Video analysis of injuries provides valuable information on the playing situation and athlete-movement patterns, which can be used to formulate these strategies. Therefore, we conducted a video analysis of the mechanism of concussion injury in junior-level rugby union and compared it with a representative and matched non-injury sample.

METHODS

Injury reports for 18 concussion events were collected from the 2011 to 2013 under-18 Craven Week tournaments. Also, video footage was recorded for all 3 years. On the basis of the injury events, a representative 'control' sample of matched non-injury events in the same players was identified. The video footage, which had been recorded at each tournament, was then retrospectively analysed and coded. 10 injury events (5 tackle, 4 ruck, 1 aerial collision) and 83 non-injury events were analysed.

RESULTS

All concussions were a result of contact with an opponent and 60% of players were unaware of the impending contact. For the measurement of head position on contact, 43% had a 'down' position, 29% the 'up and forward' and 29% the 'away' position (n=7). The speed of the injured tackler was observed as 'slow' in 60% of injurious tackles (n=5). In 3 of the 4 rucks in which injury occurred (75%), the concussed player was acting defensively either in the capacity of 'support' (n=2) or as the 'jackal' (n=1).

CONCLUSIONS

Training interventions aimed at improving peripheral vision, strengthening of the cervical muscles, targeted conditioning programmes to reduce the effects of fatigue, and emphasising safe and effective playing techniques have the potential to reduce the risk of sustaining a concussion injury.

Tackle-related injury rates and nature of injuries in South African Youth Week tournament rugby union players (under-13 to under-18): an observational cohort study

OBJECTIVES

The tackle situation is most often associated with the high injury rates in rugby union. Tackle injury epidemiology in rugby union has previously been focused on senior cohorts but less is known about younger cohorts. The aim of this study was to report on the nature and rates of tackle-related injuries in South African youth rugby union players representing their provinces at national tournaments.

DESIGN

Observational cohort study.

SETTING

Four South African Youth Week tournaments (under-13 Craven Week, under-16 Grant Khomo Week, under-18 Academy Week, under-18 Craven Week).

PARTICIPANTS

Injury data were collected from 3652 youth rugby union players (population at risk) in 2011 and 2012.

OUTCOME MEASURES

Tackle-related injury severity ('time-loss' and 'medical attention'), type and location, injury rate per 1000 h (including 95% CIs). Injury rate ratios (IRR) were calculated and modelled using a Poisson regression. A χ(2) analysis was used to detect linear trends between injuries and increasing match quarters.

RESULTS

The 2012 under-13 Craven Week had a significantly greater 'time-loss' injury rate when compared with the 2012 under-18 Academy Week (IRR=4.43; 95% CI 2.13 to 9.21, p<0.05) and under-18 Craven Week (IRR=3.52; 95% CI 1.54 to 8.00, p<0.05). The Poisson regression also revealed a higher probability of 'overall' ('time-loss' and 'medical attention' combined) and 'time-loss' tackle-related injuries occurring at the under-13 Craven Week. The proportion of 'overall' and 'time-loss' injuries increased significantly with each quarter of the match when all four tournaments were combined (p<0.05).

CONCLUSIONS

There was a difference in the tackle-related injury rate between the under-13 tournament and the two under-18 tournaments, and the tackle-related injury rate was higher in the final quarter of matches. Ongoing injury surveillance is required to better interpret these findings. Injury prevention strategies targeting the tackle may only be effective once the rate and nature of injuries have been accurately determined.

Firm-level perspectives on public sector engagement with private healthcare providers: survey evidence from Ghana and Kenya

Background

Health systems in Sub-Saharan Africa (SSA) are in urgent need of improvement. The private health sector is a major provider of care in the region and it will remain a significant actor in the future. Any efforts by SSA governments to improve health systems performance therefore has to account for the private health sector. Regional and international actors increasingly recognize importance of effectively engaging with the private health sector, and initiatives to improve engagement are underway in several countries. However, there is little systematic analysis of private health providers' view and experience with engagement.

Methodology/Principal Findings

In this study we surveyed private health facilities in Kenya and Ghana to understand the extent to which and how governments interact and engage with these facilities. The results suggest that government engagement with private health facilities is quite limited. The primary focus of this engagement is “command-and-control” type regulations to improve the quality of care. There is little attention paid to building the capacity of health care businesses through either technical or financial assistance. The vast majority of these facilities also receive no government assistance in meeting public health and social goals. Finally, government engagement with private pharmacies is often neglected and clinics receive a disproportionate share of government assistance.

Conclusions/Significance

Overall, our findings suggest that there may be considerable untapped potential for greater engagement with private health facilities—particularly pharmacies. Improving engagement will likely help governments with limited resources to better take advantage of the private sector capacity to meet access and equity objectives and to accelerate the achievement of the Millennium Development Goals.

Private sector participation and health system performance in sub-saharan Africa

Background

The role of the private health sector in developing countries remains a much-debated and contentious issue. Critics argue that the high prices charged in the private sector limits the use of health care among the poorest, consequently reducing access and equity in the use of health care. Supporters argue that increased private sector participation might improve access and equity by bringing in much needed resources for health care and by allowing governments to increase focus on underserved populations. However, little empirical exists for or against either side of this debate.

Methodology/Principal Findings

We examine the association between private sector participation and self-reported measures of utilization and equity in deliveries and treatment of childhood respiratory disease using regression analysis, across a sample of nationally-representative Demographic and Health Surveys from 34 SSA economies. We also examine the correlation between private sector participation and key background factors (socioeconomic development, business environment and governance) and use multivariate regression to control for potential confounders. Private sector participation is positively associated with greater overall access and reduced disparities between rich and poor as well as urban and rural populations. The positive association between private sector participation and improved health system performance is robust to controlling for confounders including per capita income and maternal education. Private sector participation is positively correlated with measures of socio-economic development and favorable business environment.

Conclusions/Significance

Greater participation is associated with favorable intermediate outcomes in terms of access and equity. While these results do not establish a causal link between private sector participation and health system performance, they suggest that there is no deleterious link between private sector participation and health system performance in SSA.

A phase I study of tumor treating fields (TTFields) in combination with pemetrexed for pretreated advanced non-small cell lung cancer

e18500

Background: TTFields (tumor treating fields) are low intensity, intermediate frequency, alternating electric fields which slow the growth of solid tumors in-vivo, and have shown promise in pilot clinical trials in patients with advanced solid tumors. TTFields are a regional treatment which acts both by interfering with microtubules polymerization and by physical disruption of the cell structure during cytokinesis. It has been shown previously that TTFields sensitize non-small cell lung cultures to Pemetrexed. In-Vivo, TTFields did not increase pemetrexed related toxicity. Methods: A prospective trial was performed in 14, pretreated, stage IIIb-IV, NSCLC patients. Patients with brain metastases were excluded, as were patients with abnormal marrow, kidney, liver or cardiac functions. Patients with history of clinically significant arrhythmias or those having pacemakers were excluded as well. Patients received Pemetrexed 500mg/m2 IV q3w together with daily TTFields (12 h/day) using a portable medical device (NovoTTF-100L). The device generated 2 direction (AP and Lat), 150 kHz TTFields. Patients were followed every three weeks and had a lung CT every 9 weeks. The primary endpoint was the safety and tolerability of the NovoTTF-100L device in combination with pemetrexed. Results: The 14 patients received an average of 4 courses of pemetrexed (Range 1–9) and a cumulative TTFields treatment time of 182 weeks. The device was well tolerated as indicated in the device log files which showed an average daily use of 11±1 hours. There were no device-related, nor pemetrexed-related SAEs. In addition, no unexpected abnormalities were evident in the lab tests or EKGs, done every 3 weeks for all patients. There were no reports of arrhythmias. The only device related AE seen in all patients was dermatitis under the electrodes. This improved with meticulous skin care, topical steroid use and in extreme cases oral steroids. One patient (7.6%) had a CR, 1 a PR (7.6%), 9 SD (69.2%) and 3 PD (23%). 77% of patients were progression free at 12 weeks and the 6 month survival was 89%. Conclusions: TTFields are well tolerated when given together with pemetrexed. The excellent safety profile and initial efficacy results reported here justify further clinical testing.

[Table: see text]

Oxidant tone regulates RANTES gene expression in airway epithelial cells infected with respiratory syncytial virus. Role in viral-induced interferon regulatory factor activation

Respiratory syncytial virus (RSV) produces intense pulmonary inflammation, in part, through its ability to induce chemokine synthesis in infected airway epithelial cells. RANTES (regulated upon activation, normal T-cells expressed and secreted) is a CC chemokine which recruits and activates monocytes, lymphocytes, and eosinophils, all cell types present in the lung inflammatory infiltrate induced by RSV infection. In this study we investigated the role of reactive oxygen species in the induction of RANTES gene expression in human type II alveolar epithelial cells (A549), following RSV infection. Our results indicate that RSV infection of airway epithelial cells rapidly induces reactive oxygen species production, prior to RANTES expression, as measured by oxidation of 2',7'-dichlorofluorescein. Pretreatment of airway epithelial cells with the antioxidant butylated hydroxyanisol (BHA), as well a panel of chemically unrelated antioxidants, blocks RSV-induced RANTES gene expression and protein secretion. This effect is mediated through the ability of BHA to inhibit RSV-induced interferon regulatory factor binding to the RANTES promoter interferon-stimulated responsive element, that is absolutely required for inducible RANTES promoter activation. BHA inhibits de novo interferon regulator factor (IRF)-1 and -7 gene expression and protein synthesis, and IRF-3 nuclear translocation. Together, these data indicates that a redox-sensitive pathway is involved in RSV-induced IRF activation, an event necessary for RANTES gene expression.

Inhibition of acetylcholinesterase by three new pyridinium compounds and their effect on phosphonylation of the enzyme

Three new mono-pyridinium compounds were prepared: 1-phenacyl-2-methylpyridinium chloride (1), 1-benzoylethylpyridinium chloride (2) and 1-benzoylethylpyridinium-4-aldoxime chloride (3) and assayed in vitro for their inhibitory effect on human blood acetylcholinesterase (EC 3.1.1.7, AChE). All the three compounds inhibited AChE reversibly; their binding affinity for the enzyme was compared with their protective effect (PI) on AChE phosphonylation by soman and VX. Compound 1 was found to bind to both the catalytic and the allosteric (substrate inhibition) sites of the enzyme with estimated dissociation constants of 6.9 microM (Kcat) and 27 microM (Kall), respectively. Compound 2 bound to the catalytic site with Kcat = 59 microM and compound 3 only to the allosteric site with Kall = 328 microM. PI was evaluated from phosphonylation measured in the absence and in presence of the compounds applied in a concentration corresponding to their Kcat or Kall value, and was also calculated from theoretical equations deduced from the reversible inhibition of the enzyme. Compounds 1 and 3 protected the enzyme from phosphonylation by soman and VX, whereas no protection was observed in the presence of compound 2 under the same conditions. Irrespective of the binding sites to AChE, PI for compounds 1 and 3 evaluated from phosphonylation agreed with PI calculated from reversible inhibition. Compound 3 was found to be a weak reactivator of methylphosphonylated AChE with Kr = 1.1 x 10(2) L mol-1 min-1.

Localization and characterization of white blood cell populations within the human ovary throughout the menstrual cycle and menopause

The purpose of this investigation was to localize and characterize white blood cell populations in the human ovary through its physiological life cycle. Ovaries from 30 women of reproductive age and from three post-menopausal women were embedded in paraffin or frozen. Clinical information and pathology review were used to obtain accurate menstrual cycle information and to ensure the absence of ovarian disease. Tissue sections were stained for leukocyte phenotypes and the numbers of white blood cells in the ovary were semiquantitatively assessed by two separate examiners using a 0-3 plus (+) scoring system. Our results demonstrated that macrophages and T lymphocytes were the primary immune cells of the ovary, the concentrations of which were dependent on the location and stage of development of the structures containing leukocytes. Developing follicles contained few (+) macrophages located in the theca, while atretic follicles possessed moderate (+2) numbers in the granulosa and few (+) to moderate (+2) numbers in the theca. Newly formed corpora lutea contained few (+) macrophages, while regressing corpora lutea contained abundant (+3) numbers. Human leukocyte antigen (HLA)-DR positive cells were located predominantly at sites where macrophages were present. T lymphocytes were generally not present in the developing follicle but focal, small (+) numbers were observed in blood vessels of the theca. Atretic follicles contained few (+) T lymphocytes in the granulosa and few (+) to moderate (+2) numbers in the theca. Few (+) T lymphocytes were present in new corpora lutea, while moderate (+2) to abundant (+3) numbers were present in regressing corpora lutea. T lymphocytes at all sites were UCHL1 positive. The CD4 (T helper) to CD8 (T suppressor) ration in the corpus luteum was 1:1. B-lymphocytes and natural killer cells were generally absent in the pre-menopausal ovary. The post-menopausal ovary, in contrast, only contained few (+) macrophages, T lymphocytes and natural killer cells in the stroma. In conclusion, our results indicate that the human ovary is an immunologically dynamic tissue containing activated macrophages and T lymphocytes which provide an anatomical basis for immunoendocrine interactions within the ovary.