Endurance capacity and neuromuscular fatigue following high- vs moderate-intensity endurance training: A randomized trial.

High-intensity exercise induces significant central and peripheral fatigue; however, the effect of endurance training on these mechanisms of fatigue is poorly understood. We compared the effect of cycling endurance training of disparate intensities on high-intensity exercise endurance capacity and the associated limiting central and peripheral fatigue mechanisms. Twenty adults were randomly assigned to 6 weeks of either high-intensity interval training (HIIT, 6-8×5 minutes at halfway between lactate threshold and maximal oxygen uptake [50%Δ]) or volume-matched moderate-intensity continuous training (CONT, ~60-80 minutes at 90% lactate threshold). Two time to exhaustion (TTE) trials at 50%Δ were completed pre- and post-training to assess endurance capacity; the two post-training trials were completed at the pretraining 50%Δ (same absolute intensity) and the "new" post-training 50%Δ (same relative intensity). Pre- and post-exercise responses to femoral nerve and motor cortex stimulation were examined to determine peripheral and central fatigue, respectively. HIIT resulted in greater increases in TTE at the same absolute and relative intensities as pre-training (148% and 43%, respectively) compared with CONT (38% and -4%, respectively) (P≤.019). Compared with pre-training, HIIT increased the level of potentiated quadriceps twitch reduction (-34% vs -43%, respectively, P=.023) and attenuated the level of voluntary activation reduction (-7% vs -3%, respectively, P=.047) following the TTE trial at the same relative intensity. There were no other training effects on neuromuscular fatigue development. This suggests that central fatigue resistance contributes to enhanced high-intensity exercise endurance capacity after HIIT by allowing greater performance to be extruded from the muscle.

Central and peripheral fatigue following non-exhaustive and exhaustive exercise of disparate metabolic demands.

The development of fatigue after non-exhaustive and exhaustive exercise eliciting differing metabolic demands is poorly understood. Sixteen active males completed five cycling trials. The first trial established the lactate threshold (LT) and maximal oxygen uptake (VO2max ). Two of the remaining trials were completed at a severe intensity (halfway between LT and VO2max , SI) and two at a moderate intensity (90% LT, MI). Each trial involved two non-exhaustive bouts matched for work between intensities before cycling to exhaustion. Responses to stimulation of the femoral nerve and motor cortex were determined after each bout to determine peripheral and central fatigue. Corticospinal excitability, cortical silent period (cSP), short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF) were also assessed. Non-exhaustive cycling induced greater peripheral and central fatigue in the SI compared with the MI (P < 0.05). At exhaustion, there was no difference between intensities; however, peripheral fatigue tended to be greater in the SI vs MI (-31% vs -17%, respectively, P = 0.051). Exhaustive cycling increased SICI (24%, P < 0.001) and reduced the cSP (-14%, P < 0.001) in the SI, whereas ICF was reduced in the MI (-16%, P < 0.001). These findings demonstrate exercise-induced metabolic stress accelerates the development of peripheral and central fatigue, and differentially influences intracortical excitability.

Consistency of evoked responses to dual-stimulator, single-pulse transcranial magnetic stimulation in the lower limb of people with multiple sclerosis.

The purpose of this study was to explore the within session and test-retest consistency of motor evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS) from the resting tibialis anterior (TA) muscle of 10 patients (two men, eight women) with clinically definite multiple sclerosis (MS). Dual stimulators were configured to produce a single pulse (DS/SP) through a hand-held coil. MEP were recorded in five blocks of five trials with a repeat test occurring 7-14 days later. Analysis of a trial sequence revealed the area of the first MEP trial of each block to be significantly different to subsequent trials (trials 2-5; p<0.05). We therefore discarded T1 from further analysis. Thereafter, repeated measures of analysis of variance of MEP characteristics and blocks of MEP (average of four trials) revealed no significant differences (p>0.05). The results of the repeat session revealed no significant differences in motor thresholds, MEP latency, MEP amplitude or MEP area between sessions (p>0.05). Test-retest intra-class coefficients of correlation and their 95% confidence intervals indicated high reliability (>0.80). Our results show that consistent, repeatable TMS measures can be obtained from the resting TA of MS patients using the DS/SP method.

Cardiovascular adaptation in people with multiple sclerosis following a twelve week exercise programme suggest deconditioning rather than autonomic dysfunction caused by the disease. Results from a randomized controlled trial.

BACKGROUND: Guidelines for optimal exercise doses in people with multiple sclerosis (MS) have to be established. We need to ascertain the basic physiological and perceptual response and adaptation to different exercise doses in this clinical population. AIM: The aim of this paper was to explore the response during maximal and sub-maximal exercise in people with MS prior to and following two different twelve week exercise programmes. DESIGN: Sub-analysis of per protocol exercise data of a two group, single blinded, randomised control trial. SETTING: Multicentre (community leisure and rehabilitation centres). POPULATION: Participants with MS assigned to a continuous (N.=12; mean±SE age=52.3±2.08; Barthel index median & range=19&13-20) or interval (N.=9; mean±SE age=49.3±3.5; Barthel index median & range=19&18-20) exercise programme. METHODS: Cardiovascular, respiratory and perceptual exercise response and adaption was measured at maximal and sub-maximal levels of physical exercise prior to and following a twelve week exercise programme, delivered at different intensities. RESULTS: Irrespective of the type of exercise programme followed, there was a significant increase in peak power (z=-1.98; P=0.05) and normalised oxygen uptake during unloaded cycling (z =-2.00; P=0.05). At discharge from the exercise programmes, the cardiovascular response to sub-maximal exercise had significantly changed (t(360) =-4.62; p<0.01). CONCLUSION: The response in people with MS at maximal and sub-maximal levels of physical exercise following a twelve week programme is analogous to non-diseased adults. CLINICAL REHABILITATION IMPACT: Cardiovascular adaptation in people with MS following a twelve week exercise programme suggests deconditioning rather than autonomic dysfunction caused by the disease.

The myth of pulmonary Raynaud's phenomenon: the contribution of pulmonary arterial vasospasm in patients with systemic sclerosis related pulmonary arterial hypertension.

OBJECTIVE: To investigate the contribution of cold induced pulmonary vasospasm by peripheral and central cold stimulus in exacerbating pulmonary arterial hypertension (PAH) in patients with systemic sclerosis undergoing cardiac catheterisation. METHODS: In a prospective pilot study, 21 patients with systemic sclerosis and catheter proven PAH had mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), and cardiac output (CO) measured before and after peripheral (hand immersion into cold water at 10-15 degrees C for two minutes if tolerated) and central (direct cold water at 4 degrees C injected into the right atrium) cold pressor challenge. Markers of endothelial activation, platelet function, and nitric oxide degradation were measured in blood sampled from the pulmonary artery. RESULTS: 19 of the patients (mean (SD) age, 56 (4) years; baseline mPAP, 34 (8) mm Hg; PVR, 420 (87) dyne.s.cm(-5); CO, 6.4 (1.8) l/min) tolerated cold hand immersion for the maximum two minute duration. All 21 tolerated central cold pressor challenge (three to five injections of 10 ml saline boluses at 4 degrees C). There was no significant change in haemodynamics after cold challenge by either route of provocation. Levels of endothelin-1, von Willebrand factor, fibrinogen, and 3-nitrotyrosine were raised compared with control values in patients with systemic sclerosis but without PAH, but did not change significantly after peripheral cold challenge. CONCLUSIONS: Pulmonary vasospasm in response to peripheral and centrally administered cold pressor challenge is unlikely to contribute to persistence of pulmonary arterial hypertension in patients with systemic sclerosis.

A comparison of the performance of commercially available chromogenic agars for the isolation and presumptive identification of organisms from urine.

AIMS: To compare four media-UTI medium, BBL CHROMagar, CPS ID2, and Harlequin CLED-using a collection of fully characterised organisms and subsequent "field trial". METHODS: Seven hundred and eighty seven fully characterised isolates (730 Gram negative bacteria, 47 Gram positive bacteria, and 10 yeasts) were used to test for accuracy of organism identification. To assess isolation rates and ability to detect mixed cultures, 1435 urine samples were cultured in the three best performing chromogenic media (UTI medium, BBL CHROMagar, and CPS ID2) and CLED. RESULTS: The chromogenic agars differed in their accuracy of identification, with BBL CHROMagar performing best and Harlequin CLED performing least well. Similarly, BBL CHROMagar achieved a higher overall isolation rate than UTI medium and CPS ID2. When mixed growth was defined as greater than two organism types, BBL CHROMagar detected more mixed cultures than did UTI medium and CPS ID2, although the differences were not significant. When mixed growth was defined as greater than one organism type the increased number of mixed growths detected by BBL CHROMagar became significant, largely because of differences in enterococcal isolation rates. CONCLUSION: The use of BBL CHROMagar, UTI medium, or CPS ID2 chromogenic agar as a replacement for CLED agar would improve the detection rate of contaminated urine samples. Enhanced identification helps to distinguish different species, facilitating the monitoring of bacterial resistance in support of the national antibiotic strategy. BBL CHROMagar gave the highest overall organism recovery rates, greatest ability to detect mixed cultures, and the most accurate identification of organisms.

Comparison of the performance of selenite cystine and mannitol selenite enrichment broths in the isolation of Salmonella spp. from faeces.

Over a four-month period, 4,658 routine faecal samples were examined in four laboratories and the isolation rates of Salmonella spp. from mannitol selenite (MS) and selenite cystine (SC) broths plated to xylose lysine desoxycholate agar (XLD) compared. The isolation rate by MS was 1.55% and by SC was 1.48%, a small difference which is not statistically significant. Significantly fewer colonies were selected for supplementary testing from SC than MS (p = 0.029), thus reducing confirmatory work. In laboratories where SC is already used for food and environmental work, an opportunity exists to limit stocked salmonella enrichment broths to SC alone.

Relationship of daytime asthma symptom frequency to morning peak expiratory flow.

Since management plans based on peak flow measurements are increasingly used, the relationship between peak flow rate and ensuing symptom frequency is of particular interest to the treatment of asthma. The objective of this study was to examine to what extent morning peak flow was related to symptom frequency during the day. In 168 out of 307 randomly selected adult asthmatics from a general practice population, adequate recordings of morning peak flow (amPF) and symptom frequency during the day (DSF) were obtained for 28 days. In each individual, the relationship between these two variables was studied and the mean values of these two variables over 28 days were calculated. The relationship between the means of the variables was also examined for the group as a whole. In individuals, the correlation between amPF and DSF varied widely; only 16% of patients had a good relationship (Pearson r = -1 to -0.5). For the whole group, the relationship between mean amPF and mean DSF best fitted a curvilinear model (r = -0.6). This was unaffected by age, sex or the use of inhaled steroids. For the majority of asthmatics, morning peak flow may be an unreliable predictor of expected symptoms during that day. Reliance on peak flow measurement as a tool enabling asthmatics to manage their asthma on a daily basis needs to be reconsidered.

Using information from asthma patients: a trial of information feedback in primary care.

OBJECTIVE: To test the effects of feedback of information about patients' asthma to primary care teams. DESIGN: Patients' reports of morbidity, use of health services, and drug use on questionnaire was given to primary care teams. Randomised controlled trial with general practices as the subject of the intervention was used to test effectiveness of supplying information. SETTING: Primary care in district health authority, London. SUBJECTS: 23 general practices, each of which notified at least 20 asthmatic patients aged 15-60 years for each principal. Practices were randomly allocated to an invention group (receiving feedback of information on control of asthma) or a control group (no feedback). INTERVENTION: Information on cards inserted in patients' medical records; booklet copies of information for team members; formal presentation to primary care teams; poster displays of data on patients in each practice. MAIN OUTCOME MEASURES: Type and frequency of asthma symptoms, use of health services, use of asthma drugs. RESULTS: Reported morbidity at entry to the study was substantial: 45% (818) patients reported breathlessness at least once a week. Less than half these patients were using inhaled steroids regularly. Intervention and control groups did not differ in practice or patient characteristics on entry to the study. In spite of the potential for improvement no differences were observed between the two practice groups at the end of the study--for example, breathlessness at least once a week in last six months was experienced by 36% in intervention group v 35% in control group (t = -0.27, P < 0.79); surgery attendance in last six months by 48% v 48% (t = -0.05, P < 0.96); regular use of inhaled steroids by 60% v 58% (t = 0.51, P < 0.62). CONCLUSION: Feedback to general practitioners of information about patients' asthma does not on its own lead to change in the outcome of clinical care.

Intellectual impairment, memory impairment, suggestibility and voir dire proceedings: a case study.

The psychology and psychiatry of interrogation, confession and testimony have recently become the subjects of considerable theoretical analysis, research and professional interest (Gudjonsson, 1992). A case study is reported involving a defendant whose testimony under police interrogation incriminated himself and 13 other defendants in a murder trial. Issues of intellectual impairment, memory impairment, confabulation and suggestibility were addressed in voir dire proceedings, and are described in this paper. The case also demonstrates the importance of psychological tests being administered by suitably qualified personnel.

Autobiographical memory and problem-solving strategies of parasuicide patients.

Recent research has noted the tendency of parasuicide patients to retrieve over-general autobiographical memories. Separate studies suggest problem-solving deficits within this group. The present study was concerned first with replicating these findings and, secondly, with developing a model of the relationship between over-general memory recall and poor problem-solving abilities in parasuicide patients. Anger and hopelessness were measured as markers for mood. In line with the hypotheses, the parasuicide group (N = 12) produced significantly over-general memories in contrast to a matched control group (N = 12). This occurred significantly in relation to positive cues, and latency to first responses was significantly delayed in the parasuicide group. The parasuicide group also provided fewer and less-effective problem-solving strategies than the control group, and a significant association was found between low effectiveness of problem-solving strategies and over-general memory recall in the parasuicide group. Anger and hopelessness levels were significantly higher within the parasuicide group in line with previous findings. The clinical implications of these findings are discussed.

Carotid chemoreceptor response to increases in CO2 output.

The effect on carotid chemoreceptor activity of alterations in PaCO2 oscillations produced by venous CO2 loading via the small intestines was studied in anaesthetised cats, which were paralysed and ventilated at constant frequency. Changes in PaCO2 oscillations were assessed from continuously recorded oscillations of arterial pH. Chemoreceptor activity was averaged over 20-50 pH cycles to determine the amplitude (csnd ampl) and mean level (csnd mean) of the respiratory fluctuation in discharge frequency during control and CO2 loaded periods. Two groups of 5 cats were studied. In both groups, the amplitude of the PaCO2 oscillations increased by an overall average of 74.5% (standard error, SE = 9.2) with minimal change in mean PaCO2 (average increase 0.7 mm Hg), in response to an increase in VCO2 of 77.5% (SE = 7.4). When isoxia was maintained (Group 1) csnd ampl increased by 51.3% (SE = 11.1) and csnd mean by 17.3% (SE = 7.8). In Group 2, PaO2 rose by 16.7 mm Hg (SE = 1.5) during CO2 loading and both csnd ampl and csnd mean decreased by 7.4% (SE = 9.3) and 2.3% (SE = 13.3) respectively. The results demonstrate a sensitivity of chemoreceptors to changes in VCO2 which is influenced by small changes in PaO2.

Childhood sexual experiences with adults reported by women with eating disorders: an extended series.

A total of 158 women presenting with clinical eating disorders have been investigated using a self-report questionnaire and subsequent interview concerning their recollections of sexual experiences with adults before the age of 16 and later adverse sexual experiences. About a third reported events in childhood and over half described some adverse experiences. It may be that these experiences are relevant to the subsequent illness in some cases, but greater certainty must await further research. In the meantime, inquiring about such matters would seem to be advisable in the assessment and therapy of eating-disordered patients.

Lay explanations of delinquency: global or offence-specific?

Lay explanations of delinquency have been shown to be both complex and multidimensional and to vary according to factors such as respondent age and sex. However, previous research has treated crime as a global construct, although some studies have highlighted specific attitudes towards individual crimes such as violence and sexual assault. The first of the studies described here directly compared lay explanations for three types of crime-burglary, robbery and sexual assault. Using previously validated scales to assess lay explanation of crime, it was found that there were significant differences in the rated importance of the various scales for the three types of crime. Whilst burglary and robbery were most likely to be explained by failings in education and parenting, sexual assault was most strongly explained in terms of mental instability. Some variation according to age and sex of respondent was also found. A second experiment replicated several of these findings for the crimes of robbery and rape. The race of offender did not, however, significantly influence the explanations for these two offences. Finally, the potential implications of these results are briefly discussed.

Fear of death and dying in medical students: effects of clinical experience.

Changes in the perception of death and dying during medical training were assessed, to test the hypothesis that fear is increased by exposure to dying patients. In general, clinically experienced medical students did not consistently differ from clinically inexperienced students in the intensity of fear of death. The two groups did differ in the frequency with which they thought about death. Students with clinical experience reported thinking more frequently about their own dying process and about interacting with a dying patient.

Pet owner attitudes to pets and people: a psychological study.

A preliminary attempt was made to assess how pet owners view their relationships with their pets and how pet relationships compare with human relationships. In the sample studied there was a marked variation between individuals in their perceptions but two group trends emerged. First, the pet relationship was most similar to the relationship to the individual's own child and, secondly, the pet relationship was frequently valued because of the attributes of 'dependency', 'fun/play' and 'relaxation based on absence of demands'. It is suggested that the personal meaning of pets for people needs to be further explored.

Adverse sexual experience in childhood and clinical eating disorders: a preliminary description.

Seventy-eight eating disordered patients were asked systematically about any history of adverse sexual experience. About two thirds gave such a history. The events reported were often distressing and significant to the subject. It is unclear what role such events play in the causation of later eating disorder.

Perceptions of rape in a British sample: effects of relationship, victim status, sex, and attitudes to women.

A study of attitudes to rape in a non-student British sample is reported. Ninety-six subjects (64 male, 32 female) were presented with a newspaper rape account in which previous relationship between victim and rapist and victim status were manipulated. Respondents were divided into females, males with traditional attitudes to the female role, and males with progressive attitudes. Relationship and status had no effect on perceptions but consistent effects were found for sex of respondent and attitudes to the female role.