Excess neuropeptides in lung signal through endothelial cells to impair gas exchange

Although increased neuropeptides are often detected in lungs that exhibit respiratory distress, whether they contribute to the condition is unknown. Here, we show in a mouse model of neuroendocrine cell hyperplasia of infancy, a pediatric disease with increased pulmonary neuroendocrine cells (PNECs), excess PNEC-derived neuropeptides are responsible for pulmonary manifestations including hypoxemia. In mouse postnatal lung, prolonged signaling from elevated neuropeptides such as calcitonin gene-related peptide (CGRP) activate receptors enriched on endothelial cells, leading to reduced cellular junction gene expression, increased endothelium permeability, excess lung fluid, and hypoxemia. Excess fluid and hypoxemia were effectively attenuated by either prevention of PNEC formation, inactivation of CGRP gene, endothelium-specific inactivation of CGRP receptor gene, or treatment with CGRP receptor antagonist. Neuropeptides were increased in human lung diseases with excess fluid such as acute respiratory distress syndrome. Our findings suggest that restricting neuropeptide function may limit fluid and improve gas exchange in these conditions.

The Influence of Head Impact Threshold for Reporting Data in Contact and Collision Sports: Systematic Review and Original Data Analysis

BACKGROUND

Head impacts and resulting head accelerations cause concussive injuries. There is no standard for reporting head impact data in sports to enable comparison between studies.

OBJECTIVE

The aim was to outline methods for reporting head impact acceleration data in sport and the effect of the acceleration thresholds on the number of impacts reported.

METHODS

A systematic review of accelerometer systems utilised to report head impact data in sport was conducted. The effect of using different thresholds on a set of impact data from 38 amateur senior rugby players in New Zealand over a competition season was calculated.

RESULTS

Of the 52 studies identified, 42% reported impacts using a >10-g threshold, where g is the acceleration of gravity. Studies reported descriptive statistics as mean ± standard deviation, median, 25th to 75th interquartile range, and 95th percentile. Application of the varied impact thresholds to the New Zealand data set resulted in 20,687 impacts of >10 g, 11,459 (45% less) impacts of >15 g, and 4024 (81% less) impacts of >30 g.

DISCUSSION

Linear and angular raw data were most frequently reported. Metrics combining raw data may be more useful; however, validity of the metrics has not been adequately addressed for sport. Differing data collection methods and descriptive statistics for reporting head impacts in sports limit inter-study comparisons. Consensus on data analysis methods for sports impact assessment is needed, including thresholds. Based on the available data, the 10-g threshold is the most commonly reported impact threshold and should be reported as the median with 25th and 75th interquartile ranges as the data are non-normally distributed. Validation studies are required to determine the best threshold and metrics for impact acceleration data collection in sport.

CONCLUSION

Until in-field validation studies are completed, it is recommended that head impact data should be reported as median and interquartile ranges using the 10-g impact threshold.

Metabolic Differences Between Shod and Barefoot Walking in Children

Footwear affects the biomechanics of children's gait; however, there has been less research addressing the energetics of walking with and without shoes. This study investigated the effects of barefoot and shod walking on metabolic parameters in children. 25 children (9.7±1.4 years) walked at a self-selected pace for 5 min on an instrumented treadmill under 2 footwear conditions (barefoot, running shoe). Vertical oscillations of centre of mass were calculated from ground reaction forces. Expired gases were collected in the last minute of each trial. Paired t-tests revealed significantly higher oxygen consumption (17.6±2.5 ml.kg(-1).min(-1) vs. 16.3±3.1 ml.kg(-1).min(-1)), energy expenditure (3.25±0.86 kcal.min(-1) vs. 2.97±0.68 kcal.min(-1)), and economy (298.2±47.5 ml.kg(-1).km(-1) vs. 275.9±56.9 ml.kg(-1).km(-1)) during the shod condition. There was no difference in substrate utilization between conditions. The barefoot condition elicited a smaller centre of mass vertical displacement (1.24±0.14 cm vs. 1.34±0.17 cm). At a natural walking speed, barefoot walking is more economical than shod walking at the same velocity in children. The higher energy cost of shod walking should be considered when evaluating the use of footwear by children.

Use of the King-Devick test for sideline concussion screening in junior rugby league

AIM

To determine whether the King-Devick (K-D) test used as a sideline test in junior rugby league players over 12 matches in a domestic competition season could identify witnessed and incidentally identified episodes of concussion.

METHODS

A prospective observational cohort study of a club level junior rugby league team (n=19) during the 2014 New Zealand competition season involved every player completing two pre-competition season baseline trials of the K-D test. Players removed from match participation, or who reported any signs or symptoms of concussion were assessed on the sideline with the K-D test and referred for further medical assessment. Players with a pre- to post-match K-D test difference >3s were referred for physician evaluation.

RESULTS

The baseline test-retest reliability of the K-D test was high (rs=0.86; p<0.0001). Seven concussions were medically identified in six players who recorded pre- to post-match K-D test times greater than 3s (mean change of 7.4s). Post-season testing of players demonstrated improvement of K-D time scores consistent with learning effects of using the K-D test (67.7s vs. 62.2s).

DISCUSSION

Although no witnessed concussions occurred during rugby play, six players recorded pre- to post-match changes with a mean delay of 4s resulting in seven concussions being subsequently confirmed post-match by health practitioners. All players were medically managed for a return to sports participation.

CONCLUSION

The K-D test was quickly and easily administered making it a practical sideline tool as part of the continuum of concussion assessment tools for junior rugby league players.

The effect of player positional groups on the nature of tackles that result in tackle-related injuries in professional rugby league matches

AIM

The aim of this study was to describe the effect of player positional groups on the nature of tackles that result in tackle-related injuries in professional rugby league matches.

METHODS

Prospective observational epidemiology analyses for tackle-related injuries and video analyses for the nature of tackles were conducted for a single team in the National Rugby League (NRL) throughout the 2007 and 2008 competitions for a total of 48 games. Risk ratios (RR) were calculated for comparisons between positional groups (adjustable, hit-up forwards or outside backs).

RESULTS

The total missed match tackle-related injury rate was 57.8 per 1 000 player hours. Hit-up forwards recorded significantly more total tackle-related injuries than outside backs (RR: 1.3; P=0.049), but not more than adjustables (RR: 1.0; P=0.922). Hit-up forwards recorded significantly more chest-back tackle-related injuries than adjustables (RR: 6.0; P=0.008). Outside backs recorded significantly more tackle injuries as the ball carrier than the tackler (RR: 2.4; P=0.015) while adjustables recorded significantly more tackle injuries as the tackler than the ball carrier (RR: 1.8; P<0.001). Hit-up forwards had a higher incidence of contusions, and sprains while adjustables had a higher incidence of fracture/dislocations. There were no differences in injury severity between the positional groups.

CONCLUSION

Player positional group had an effect on tackle-related injury type and injury site. Hit-up forwards and outside backs recorded more tackle-related injuries as a ball carrier than as a tackler, while in contrast, adjustables recorded more tackle-related injuries as the tackler than the ball carrier.

A retrospective review over 1999 to 2007 of head, shoulder and knee soft tissue and fracture dislocation injuries and associated costs for rugby league in New Zealand

King et al. reported that of 5 941 moderate to serious claims resulting in medical treatment for rugby league injuries, the knee, shoulder, and head and neck body sites and soft tissue and fracture-dislocation injuries were most frequent and costly in the New Zealand national no-fault injury compensation corporation database during 1999 to 2007. However, additional analyses of knee, shoulder and head and neck body sites by soft tissue and fracture-dislocation injury types was required to enable a greater understanding of the nature of injuries most likely to be seen by sports medical personnel dealing with rugby league players. From 1999 to 2007 the injury claims and costs for head and neck soft tissue, fracture-dislocations, shoulders soft tissue significantly increased. Knee soft tissue injury claims and costs significantly decreased from 1999 to 2007. There was no significant difference in knee fracture-dislocation injury claims but there was a significant increase in knee fracture-dislocation injury costs from 1999 to 2007. Changes in the nature of injuries may be related to changes in defensive techniques employed in rugby league during this time. Sports medical personnel dealing with rugby league players should focus their injury prevention strategies on reducing musculoskeletal injuries to the head and shoulder. There should be a focus on increasing awareness of correct tackling technique, head injury awareness and management of suspected cervical spine injuries.

Olympic lightweight and open-class rowers possess distinctive physical and proportionality characteristics

Rowers competing at the 2000 Olympic Games were measured for 38 anthropometric dimensions. The aim was to identify common physical characteristics that could provide a competitive advantage. The participants included 140 male open-class rowers, 69 female open-class rowers, 50 male lightweight rowers, and 14 female lightweight rowers. Body mass, stature, and sitting height were different (P < 0.01) between the open-class and lightweight rowers, as well as a comparison group of healthy young adults ("non-rowers", 42 males, 71 females), for both sexes. After scaling for stature, the open-class rowers remained proportionally heavier than the non-rowers, with greater proportional chest, waist, and thigh dimensions (P < 0.01). Rowers across all categories possessed a proportionally smaller hip girth than the non-rowers (P < 0.01), which suggested the equipment places some constraints on this dimension. Top-ranked male open-class rowers were significantly taller and heavier and had a greater sitting height (P < 0.01) than their lower-ranked counterparts. They were also more muscular in the upper body, as indicated by a larger relaxed arm girth and forearm girth (P < 0.01). For the male lightweight rowers, only proportional thigh length was greater in the best competitors (P < 0.01). In the female open-class rowers, skinfold thicknesses were lower in the more highly placed competitors (P < 0.01). In conclusion, the rowers in this sample demonstrated distinctive physical characteristics that distinguish them from non-rowers and other sports performers.

A comparative study of metabolic engineering anti-metabolite tolerance in Escherichia coli

A problem in strain engineering is that mutations that benefit the expression of a phenotype in one environment may impose a cost to biological fitness in a new environment. The overall objective of this study was to improve understanding of this phenomenon within the context of a classic anti-metabolite selection strategy. We have engineered Escherichia coli using three mutagenesis techniques (chemical mutagenesis, insertional mutagenesis, and plasmid-based overexpression) and assessed the relative costs and benefits to biological fitness of mutants selected for tolerance to five amino acid analogs whose target amino acids (glutamatic acid, aspartic acid, tryptophan, glycine, and serine) differ in metabolic connectivity and biosynthetic energy requirements. Our major findings include (i) the fold increase in anti-metabolite tolerance, independent of mutagenesis strategy, was much greater for aspartic acid beta-hydroxamate (AAH) compared to all other tested hydroxamates, (ii) increased tolerance to glutamic acid gamma-hydroxamate (GAH) was not achieved using any of the mutagenesis strategies, and (iii) characteristics of the anti-metabolite, rather than those of the corresponding metabolite, were more important in determining the ability to increase tolerance.

The luteal heat cycle of the breast in disease

Wearing a special thermometric brassiere, selected women self-measured their breast surface temperature. These measurements were made during one hour each evening at home for one menstrual cycle under standard conditions of overclothing and room temperature. To stage their cycle they also collected daily samples of saliva in their freezer for immuno-assay of progesterone concentration in the laboratory. A total of 82 women participated, most having young families. This total included four groups, a control group (N = 25) and three 'disease' groups, namely: family history of breast cancer (14); benign breast disease (12); and a 'cancer-associated' group (31) who had had previous cancer surgery. A significant breast temperature rhythm with a period at or about 28 days was found not only in the controls but also in the three groups of breasts designated 'disease'. Nevertheless, consistent rhythm abnormalities were found in all the disease groups. Most evident was a hyperthermia throughout the cycle, a reduction in the rhythm amplitude, and a tendency for the breast temperature rhythm to be manifest 1-2 days earlier in the menstrual cycle.

A non-invasive test for the pre-cancerous breast

This paper describes a non-invasive, self-measured procedure by which the precancerous breast can be distinguished from the normal breast. The method involves wearing a specially designed thermometric brassiere for 90 min each evening at home through one menstrual cycle. Profiles of progesterone through the cycle, obtained from daily saliva sampling, and determination of the steroid content by radioimmunoassay, are made to allow the status and calendar date timing of the luteal phase to be established. Thus, cycles can be synchronised across subjects. In this study, two types of breast were compared: 50 normal breasts and 41 age-matched precancerous breasts. Differences between the groups were striking in terms of amplitude, phasing and average temperature during the luteal heat cycle. When these parameters and others were used as predictors in a linear discrimination and/or neural net analysis, a sensitivity and specificity of > 90% was achieved.

The luteal heat cycle of the breast in health

Wearing a special thermometric brassiere, twenty-five normal women self-measured their breast surface temperature. The subjects averaged 39 years of age and all were parous. Observations were made for one hour each evening for one menstrual cycle under semi-standardized domestic conditions. They also collected daily samples of saliva for radioimmunoassay of progesterone concentration. The surface temperature of the breast is relatively cold around mid-cycle; thereafter, and without interruption in averaged data, the temperature increases steadily by about 1 degree C over the 12 days of the luteal phase; around the time of the menses, it falls rapidly. This heat rhythm does not occur in peri-menopausal low progesterone menstrual cycles or in patients where the breast tissue has been irradiated for cancer treatment.