A consideration of the paradigm of exercise physiology

Exercise physiology, in terms of the history of biological sciences, is quite young and has a rather tumultuous history - as it spans physical education, health & medicine, sport science, and biology. This has led to the development of differing definitions, research approaches, practices and goals. This is easily seen in the presence of competing and non-universally adopted definitions of fitness. Such internal inconsistencies portray to the outside world a discipline experiencing the problems associated with a changing paradigm. Every science requires the presence of a paradigm that both describes and guides the evolution of thinking, experimentation, and the application of such. It is argued here that exercise physiology has been operating without benefit of a satisfactory and relevant paradigm. A further proposition is that the required disciplinary definitions derived from an articulated paradigm are also absent. A paradigmatic scheme based on biological dogma is presented along with proposed definitions.

Unique microstructural design of ceramic scaffolds for bone regeneration under load

During the past two decades, research on ceramic scaffolds for bone regeneration has progressed rapidly; however, currently available porous scaffolds remain unsuitable for load-bearing applications. The key to success is to apply microstructural design strategies to develop ceramic scaffolds with mechanical properties approaching those of bone. Here we report on the development of a unique microstructurally designed ceramic scaffold, strontium-hardystonite-gahnite (Sr-HT-gahnite), with 85% porosity, 500μm pore size, a competitive compressive strength of 4.1±0.3MPa and a compressive modulus of 170±20MPa. The in vitro biocompatibility of the scaffolds was studied using primary human bone-derived cells. The ability of Sr-HT-gahnite scaffolds to repair critical-sized bone defects was also investigated in a rabbit radius under normal load, with β-tricalcium phosphate/hydroxyapatite scaffolds used in the control group. Studies with primary human osteoblast cultures confirmed the bioactivity of these scaffolds, and regeneration of rabbit radial critical defects demonstrated that this material induces new bone defect bridging, with clear evidence of regeneration of original radial architecture and bone marrow environment.

Aorto-oesophageal fistula following TEVAR: an unusual cause of mediastinal air

Aorto-oesophogeal fistula (AEF) following thoracic endovascular aneurysm repair (TEVAR) has an incidence of 1.7%. Patients often present with constitutional symptoms or haematemesis and the condition is frequently fatal. We present a 79-year-old man who underwent TEVAR to exclude a ruptured 5.3 cm aneurysm. He re-presented with persistent fever and haematemesis and initially underwent oesophogastroduodenoscopy and biopsy to exclude oesophageal carcinoma. Following CT scanning AEF was diagnosed and extra-anatomical reconstruction was performed. Two months later he suffered a sudden and unexpected large bleed into his ventilator circuits from his tracheostomy and died. Haematemesis following TEVAR should raise clinical suspicion of AEF. Early and accurate diagnosis is paramount in view of the high attendant mortality. CT should be considered the initial investigation of choice.

Azacitidine fails to eradicate leukemic stem/progenitor cell populations in patients with acute myeloid leukemia and myelodysplasia

Epigenetic therapies demonstrate significant clinical activity in acute myeloid leukemia (AML) and myelodysplasia (MDS) and constitute an important new class of therapeutic agents. However hematological responses are not durable and disease relapse appears inevitable. Experimentally, leukemic stem/progenitor cells (LSC) propagate disease in animal models of AML and it has been postulated that their relative chemo-resistance contributes to disease relapse. We serially measured LSC numbers in patients with high-risk AML and MDS treated with 5'-azacitidine and sodium valproate (VAL-AZA). Fifteen out of seventy-nine patients achieved a complete remission (CR) or complete remission with incomplete blood count recovery (CRi) with VAL-AZA therapy. There was no significant reduction in the size of the LSC-containing population in non-responders. While the LSC-containing population was substantially reduced in all patients achieving a CR/CRi it was never eradicated and expansion of this population antedated morphological relapse. Similar studies were performed in seven patients with newly diagnosed AML treated with induction chemotherapy. Eradication of the LSC-containing population was observed in three patients all of whom achieved a durable CR in contrast to patients with resistant disease where LSC persistence was observed. LSC quantitation provides a novel biomarker of disease response and relapse in patients with AML treated with epigenetic therapies. New drugs that target this cellular population in vivo are required.

So how do you see our teaching? Some observations received from past and present students at the Maurice Wohl Dental Centre

This study explores student perceptions of clinical teaching delivered at the Maurice Wohl Dental Centre, King's College London Dental Institute. An on-line survey together with two paper-based questionnaires were used to invite three immediate past cohorts of final-year dental students to reflect and comment on their experiences during their year of attendance. Supporting data from current student focus group and face-to-face interviews were also included in the study. The principal findings from these triangulated methodologies were that the overwhelming majority of students felt they got on very well with their teachers. The development of a positive professional relationship with the teacher appeared to motivate students to work better. Teaching thought to be overly didactic and authoritarian would not be well received. The principal teaching style identified at the Centre was considered to be supportive and nurturing, encouraging a self-motivated and reflective approach to clinical practice.

Concentrations of salivary testosterone, cortisol, and immunoglobulin A after supra-maximal exercise in female adolescents

The aim of this study was to examine the effect of supra-maximal exercise on circulating concentrations of salivary testosterone, salivary cortisol, and salivary immunoglobulin A in female adolescents. Nineteen apparently healthy females aged 15-16 years participated in this study. All participants completed 668 s sprints, interspersed with 30 s recovery intervals on a cycle ergometer. Salivary testosterone, cortisol, and immunoglobulin A samples were taken before and 5 min after exercise. Experimental procedures continued over two mornings, at least 3 h after a light breakfast. Participants refrained from performing any strenuous physical activity for at least 24 h prior to the exercise test. None of the participants were engaged in a structured training programme. The group mean (± s) for peak power output was 562 ± 113.0 W. Female adolescents recruited for this study showed no changes in salivary testosterone, cortisol or immunoglobulin A following repeated bouts of supra-maximal cycling (P > 0.05). To date, there has been a paucity of information concerning adolescents' hormonal and mucosal immune function responses to supra-maximal exercise. Our data provide further guidance with regard to physical activities and sports prescription for female adolescents. Further research, on a larger sample of females, is required to elucidate the physiological significance of these findings.

Immunoendocrine responses over a three week international rugby union series

AIM

This study evaluated changes in immunoendocrine makers over an international series in professional rugby union players (N.=8).

METHODS

Venous bloods were taken on camp-entry, as well as before and after (0, 14 and 38 h) two games spaced over 21-days. Samples were analysed for changes in serum C-reactive protein (CRP), cortisol (C), testosterone (T), blood leukocytes, interleukin 6 (IL-6) and creatine kinase (CK).

RESULTS

Significant reductions in CK activity and CRP concentrations were evident on day 5 (pre-game 1) when compared to camp-entry (day 1); P<0.05. A large acute-phase response was observed following both games. Differences in the magnitude of this response appeared dependant on the number of collisions players experienced during play. Compared to camp-entry, sharp increases in C (40%) and decreases (37%) in T were evident after both games; P<0.05. A gradual increase in T/C ratio was observed throughout the tournament; values 35% and 45% higher on days 19 and 21 than those observed at camp-entry (P<0.05).

CONCLUSION

Current data suggests that improved physiological recovery can be achieved during an international rugby union series. Monitoring of previous club activity is essential to ensure optimal player readiness prior to participation in international rugby union games.

Endotoxin removal devices for the treatment of sepsis and septic shock

A substantial body of experimental and clinical evidence suggests that neutralising or removing lipopolysaccharide endotoxin would be an effective adjunctive approach to the management of Gram-negative sepsis. Polymyxins are a group of cyclic cationic polypeptide antibiotics. Although they have useful antimicrobial activity against Gram-negative bacteria, their clinical use has been limited because of toxicity. However, in addition to their antimicrobial property, polymyxins can bind to and neutralise endotoxin. Thus, investigators have explored the possibility of using polymyxin bound to a solid-phase carrier for specific haem-adsorption in patients with sepsis, thereby retaining the lipopolysaccharide-binding properties but minimising systemic toxic effects. This system has been widely used in Japan for many years, but convincing clinical evidence of efficacy is lacking. A recent Italian study has some promising data. Although polymyxin has been the principal agent used to explore this approach, other molecules have the ability to bind endotoxin, and some of these have very recently been proposed as the basis for other endotoxin-removal devices. The available evidence is reviewed to assess the potential use of such devices in clinical practice.

Direct Hits to the Head during Amateur Boxing is Associated with a Rise in Serum Biomarkers for Brain Injury

Boxing exposes participants to the physiological response to high intensity exercise and also to direct body and brain trauma. Amateur boxing is increasing and females have also been included in the Olympics. The aim of this study is to assess the stress response and possible brain injury incurred during a match by measuring serum biomarkers associated with stress and cellular brain injury before and after combat. Sixteen male amateur boxers were studied retrospectively. The study population was divided into two groups: (a) a group that received predominantly punches to the head (PTH) and (b) a group that received predominantly punches to the body (PTB). Blood samples were taken before and five minutes after each contest. They were analysed for S-100B, neuron-specific enolase (NSE), creatine kinase (CK) and cortisol. The PTH group received direct contacts to the head (not blocked, parried or avoided) and to the body ( n=8, age: 17.6 ± 5.3, years; height: 1.68 ± 0.13, meters; mass: 65.4 ± 20.3, kg). The PTB group received punches to the body including blocked and parried punches, but received no direct punches to the head, ( n=8, mean ± SD, age: 19.1 ± 3.2 years; height: 1.70 ± 0.75, meters; mass: 68.5 ± 15 kg). Significant increases ( P<0.05) were observed between pre- and post-combat serum concentrations in serum concentrations in PTH of S-100B (0.35 ± 0.61 vs. 0.54 ± 0.73, μg.L−1) NSE (19.7 ± 14 vs.31.1 ± 26.6, ng.ml−1) and cortisol (373 ± 202 vs. 756± 93, nmol.L−1). Significant increases ( P<0.05) of creatine kinase were recorded in both groups. This study demonstrates significant elevations in neurochemical biomarkers in boxers who received direct blows to the head. However, further work is required to quantify this volumetric brain damage and long term clinical sequelae.

Secular trends in established and novel cardiovascular risk factors in Welsh 12-13 year olds: a comparison between 2002 and 2007

BACKGROUND

This study examines CVD risk factors trends in Welsh adolescents between 2002 and 2007.

PARTICIPANTS AND METHODS

CVD risk factor data was examined from two cross-sectional studies. The first study (73 participants; aged 12.9 ± 0.3 years) was completed in 2002. The second study (90 participants; aged 12.9 ± 0.4 years) was conducted in 2007. Measurements included body mass index (BMI), waist circumference (WC), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, fibrinogen (Fg) and high-sensitivity C-reactive protein (hs-CRP).

RESULTS

In boys, mean BMI and WC were lower in 2007, although not significantly (p ≥ 0.05). In 2007, there were improvements in mean lipid, Fg and hs-CRP concentrations in both sexes (p < 0.05). In 2002, 42.8% of boys and 34.2% of girls were overweight or obese; in 2007, this was 23.7% and 28.9% for boys and girls, respectively. More adolescents in 2002 exceeded the recommended levels for lipids, Fg and hs-CRP.

CONCLUSION

This is the only study to examine CVD risk factor trends in Welsh adolescents. Although overweight continues to be widespread in 12-13 year olds, this study did not identify significant mean changes in overweight and obesity between 2002 and 2007. Overall, the data presented a positive trend in lipid profile and inflammatory factors.

Migraines with and without aura and their response to preventive therapy with topiramate

Data from the Prolonged Migraine Prevention (PROMPT) with Topiramate trial were evaluated post hoc to determine whether topiramate could prevent migraine auras, and whether its efficacy in preventing migraine headaches was similar in patients with (MA; n = 269) and without (MoA; n = 542) aura. Migraines and auras were recorded during prospective baseline, 6-month open-label (OL) topiramate and 6-month double-blind (DB), placebo-controlled phases. In the last 28 OL days, migraines without aura and migraine auras decreased by 43.1% and 54.1%, respectively, in MA patients. MoA patients experienced a 44.3% reduction in migraines. In the DB phase, increases in migraines with placebo vs. topiramate were similar to the full study, but were generally not statistically significant, probably due to lack of power in the subgroup analysis. Similarly, there were no statistically significant changes in number of auras between groups. Thus, topiramate appears to reduce migraine auras in parallel with headache reductions, which are similar in patients with and without aura.