Chinese response to allergy and asthma in Olympic athletes

China is going to host the Games of the XXIX Olympiad from 8–24 August 2008 in Beijing. The number of athletes and accompanying individuals expected to arrive at China for the Beijing Olympics is estimated at over 10 000 and among them at least 2 000 (20%) are suspected to suffer from respiratory allergies. It is important to monitor the pollen counts and improve air quality in Beijing because Olympic athletes would be exposed to airborne allergens and pollutants during competitions which could hinder peak performance. The main pollen and spore families in Beijing are Artemisia, Ambrosia, Chenopodiaceae and Gramineae. They can reach around 307 000 grains of pollen/1000 m³ of air in August. Economic development in China is usually linked with worsening of air quality. Due to the adoption of various control measures, the ambient air quality in a number of areas in Beijing has actually improved. The ambient air TSP and SO₂ levels in Beijing have been decreasing in the last decade. However, ambient air NO _x level has been increasing due to the increased number of motor vehicles. Nevertheless, dedicated medical facilities in Beijing will provide medical services to athletes and delegations from all over the world during the Beijing Olympic Games.     

Relations between psychometric profiles and cardiovascular autonomic regulation in physical education students

This study was designed to investigate physical education (PE) students the link between mood disturbances, caused by psychological or physical stressors associated with studying, and the autonomic nervous system modifications. PE students completed the profile of mood state (POMS) questionnaire at the end of the university year. Heart rate variability (HRV) was then measured during a head-up tilt test (HUT) in those with the highest and lowest total mood disturbance (TMD) scores on three successive POMS. Among the 218 students who completed the POMS (85 female and 137 male), 65 had high TMD scores, suggesting mood disturbances and fatigue. The final sample included 12 subjects in the potentially overtrained (POT) group and 16 subjects in the control (CTL) group. A greater decrease of two indices of the autonomic system (SD1 and RMSSD) was observed during the HUT in the POT than in the CTL group (P < 0.05). The depression (Dep) and vigor (Vig) subscales of POMS were correlated with several HRV indices. More specifically, in the POT group, the Vig score was correlated with autonomous activity in the supine position, and the Dep score with percentages of change of sympatho-vagal activity during the HUT. This suggests that (1) POT students could present a weaker autonomic response to HUT, (2) Dep and Vig subscales of the POMS questionnaire may indicate autonomic dysregulations.     

Socio-economic factors in relation to lipid profiles in young girl athletes

Summary The influence of socio-economic factors on blood lipid values was studied in 4 groups of young female athletes. Based on type of sport (gymnastics and swimming) and of training intensity, the participants were subdivided into 25 talented, high achievement gymnasts (age 12.3±1.6 (SD) year), 42 non-talented, low achievement gymnasts (age 12.0±1.2 (SD) year), 12 high achievement swimmers (age 10.3±1.6 (SD) year), and 24 low achievement swimmers (age 10.8±1.6 (SD) year). With respect to socio-economic factors, no significant differences were observed between the two gymnastic groups nor between the two swimming groups. The blood lipid values revealed a significantly higher low density lipoprotein-cholesterol level and significantly lower high density lipoprotein-cholesterol/total cholesterol and high density lipoprotein-cholesterol/low density lipoprotein cholesterol ratios in the talented gymnasts as compared to the non-talented gymnasts. In the high achievement swimmers, low density lipoprotein-cholesterol and triglyceride levels were significantly lower and high density lipoprotein-cholesterol/total cholesterol was significantly higher as compared to the other swimmers. The Spearman rank order correlation coefficients for the relationships between socio-economic factors and blood lipid values were mostly weak or inconsistent. Therefore, no major influence of socio-economic factors on blood lipid values could be demonstrated in the groups investigated.     

Spontaneous autonomic activity as related to psychopathy

Spontaneous fluctuations and levels in skin conductance and finger pulse volume recordings were studied in criminal subjects during three experimental periods, before, during and after a series of auditory stimuli, and related to psychopathy as estimated by scores in the Gough delinquency scale (De). The sample was subdivided into two groups, containing subjects with scores above (HD) and below (LD) the median in the De scale. Analyses of variance yielded significant group x period interaction effects for skin conductance fluctuation and level measures. The more psychopathic group (HD) had a lower number of skin conductance fluctuations in stimulation and post-stimulation periods, and had lower levels, decreasing over periods. No differences were obtained in the pulse volume measurements. The lower skin conductance reactivity in the more psychopathic subjects was discussed in terms of lower cortical arousal, and the implications for the interpretation of skin conductance fluctuations were analysed.     

Resting and postexercise cardiac autonomic control in trained master athletes

This study used measures of heart rate variability during recovery from high-intensity exercise in trained Master athletes to examine postexercise cardiac autonomic regulation. Seven males (mean age 52.1 +/- 3.3 yr; mass 85.1 +/- 18.0 kg) and 6 females (mean age 50.5 +/- 2.9 yr; mass 63.1 +/- 6.0 kg) performed incremental exercise to an intensity that induced a >4.5 mmol capillary blood lactate concentration, followed by incremental exercise to volitional exhaustion (VO2(max)). A 6 min ECG recording before (Pre) and after (Post) exercise was analyzed in the time (mean rr interval, sd rr) and frequency domains (total power, very low frequency [VLF: 0-0.04 Hz], low frequency [LF: 0.04-0.15 Hz], high frequency [HF: 0.15-0.4 Hz]). VO2(max) for males and females was 49.4 +/- 7.1 ml kg(-1) min(-1) and 45.1 +/- 10.1 ml kg(-1) min(-1), respectively. Lower mean rr interval (Pre: 1,048 +/- 128 ms; Post: 730 +/- 78 ms; P < 0.001) and lower sd rr (Pre: 77 +/- 30 ms; Post: 43 +/- 17 ms; P < 0.001) were recorded following exercise, with no differences based on gender. Total power decreased following exercise (Pre: 6,331 +/- 6,119 ms; Post: 1,921 +/- 1,552 ms). When normalized for changes in total power, a decreased HF component (Pre: 34.52 +/- 14.79 n.u.; Post: 18.49 +/- 13.64 n.u.; P < 0.05) with no change in LF component (Pre: 61.00 +/- 18.66 n.u.; Post: 69.63 +/- 23.97 n.u.; P = 0.34) was recorded. No gender differences in HRV in the frequency domain were recorded. Decreased heart rate variability in both time and frequency domains suggested an increased parasympathetic withdrawal during the autonomic control of postexercise tachycardia in trained Master athletes.     

Cardiac and autonomic responses to change in posture or vitamin C supplementation in sickle cell anemia subjects

Autonomic function following change in posture with or without vitamin C supplementation was studied in ten (10) sickle cell anemia (SCA) and twelve (12) non-sickle cell anemia (NSCA) subjects. Arterial blood pressure and electrocardiographic measurements were taken in the supine position on a couch 80 cm high and immediately on assumption of the upright position. Vitamin C was then administered orally (300 mg/day for 6 weeks). At the end of the period, blood pressure and ECG measurements were again made in the supine position and in response to change in posture.

Change in posture significantly decreased QRS amplitude, QRS duration, PR interval, RR interval and MABP but increased HR and rate pressure product (RPP) in both groups of subjects. The HR and RPP responses were significantly higher in NSCA than in SCA subjects (p < 0.001, respectively). Vitamin C caused greater reductions in QRS duration (p < 0.01), PR duration p < 0.001) in the NSCA subjects than in SCA subjects. It caused, however, greater reduction in RR duration (p < 0.001) and MABP in SCA subjects than in NSCA subjects. It also caused significantly greater increases in HR and RPP (p < 0.001, respectively) in the SCA subjects than in NSCA subjects. After vitamin C supplementation, change in posture decreased RR interval (p < 0.001), QT interval (p < 0.01) and MABP (p < 0.05) but increased RPP (p < 0.01) in NSCA subjects. In SCA subjects, there was a fall in RR interval (p < 0.001) and MABP (p < 0.01), but elevated RPP (p < 0.001). Changes (Δ) in MABP, HR and RPP were similar between NSCA and SCA subjects. In conclusion, these findings indicate a blunted cardiovascular autonomic response to change in posture in sickle cell anemia subjects. Chronic, oral, low-dose vitamin C supplementation equilibrates this response with those of non-sickle cell anemia subjects.     

Atrial automaticity and atrioventricular conduction in athletes: contribution of autonomic regulation

Little is known about the sinoatrial automatism and atrioventricular conduction of trained individuals who present a normal resting electrocardiogram. We used transesophageal atrial stimulation, a minimally invasive technique, to evaluate aerobically trained athletes (n=10) and sedentary individuals (n=10) with normal resting electrocardiograms, to test the hypothesis that parasympathetic tone, as detected by heart rate variability, could be associated with changes in sinoatrial automatism and atrioventricular conduction. Corrected sinus node recovery time tended to be longer in athletes than in sedentary individuals, but this difference did not reach statistical significance. The Wenckebach point occurred at a lower rate in athletes than in the controls. Over a 24-h period of measurement, the mean RR interval was longer in the athletes than in the sedentary individuals. The mean square root of successive differences (rMSSD) tended to be higher in athletes than in controls, but this difference did not reach statistical significance. There was a moderate correlation (r=0.48, P < 0.05) between the index of atrioventricular conduction, the rate at the Wenckebach point, and the logarithmically transformed rMSSD. Thus, as a corollary to its effects on the sinus node, where increased parasympathetic tone, decreased sympathetic tone, and non-autonomic components may contribute to sinus bradycardia, it is possible that athletic training may also induce intrinsic adaptations in the conduction system, which could contribute to the higher prevalence of atrioventricular conduction abnormalities observed in athletes. Accepted: 2 January 2000     

Interactions between posture and locomotion: motor patterns in humans walking with bent posture versus erect posture

Human erect locomotion is unique among living primates. Evolution selected specific biomechanical features that make human locomotion mechanically efficient. These features are matched by the motor patterns generated in the CNS. What happens when humans walk with bent postures? Are normal motor patterns of erect locomotion maintained or completely reorganized? Five healthy volunteers walked straight and forward at different speeds in three different postures (regular, knee-flexed, and knee- and trunk-flexed) while their motion, ground reaction forces, and electromyographic (EMG) activity were recorded. The three postures imply large differences in the position of the center of body mass relative to the body segments. The elevation angles of the trunk, pelvis, and lower limb segments relative to the vertical in the sagittal plane, the ground reaction forces and the rectified EMGs were analyzed over the gait cycle. The waveforms of the elevation angles along the gait cycle remained essentially unchanged irrespective of the adopted postures. The first two harmonics of these kinematic waveforms explain >95% of their variance. The phase shift but not the amplitude ratio between the first harmonic of the elevation angle waveforms of adjacent pairs was affected systematically by changes in posture. Thigh, shank, and foot angles covaried close to a plane in all conditions, but the plane orientation was systematically different in bent versus erect locomotion. This was explained by the changes in the temporal coupling among the three segments. For walking speeds >1 m s(-1), the plane orientation of bent locomotion indicates a much lower mechanical efficiency relative to erect locomotion. Ground reaction forces differed prominently in bent versus erect posture displaying characteristics intermediate between those typical of walking and those of running. Mean EMG activity was greater in bent postures for all recorded muscles independent of the functional role. The waveforms of the muscle activities and muscle synergies also were affected by the adopted posture. We conclude that maintaining bent postures does not interfere either with the generation of segmental kinematic waveforms or with the planar constraint of intersegmental covariation. These characteristics are maintained at the expense of adjustments in kinetic parameters, muscle synergies and the temporal coupling among the oscillating body segments. We argue that an integrated control of gait and posture is made possible because these two motor functions share some common principles of spatial organization.     

Associations between psychological profiles and diseases: examining hemispheric dominance and autonomic activation as underlying regulators

Personality profiles are often typical for specific illnesses, e.g., the type A personality and heart disease. We hypothesize that many more such patterns exist, and have developed a scheme in which many diseases can be classified, depending on hemispheric dominance (i.e., integrated, intellectualising or emotional) and type of autonomic control (i.e., dominance of either sympathetic or parasympathetic system, or an increase in both types of autonomic outflow). Our hypothesis is based on recent findings in neurophysiology, involving the early rearing environmental effects on the developing orbitofrontal cortex, and attachment theory. We conclude with implications for therapy, and a discussion of the limitations of our hypothesis.     

Discriminating between different modes of inheritance in genetic disease

A genetics program library (Morton 1969a) was used to study the problem of discrimination between different modes of inheritance in genetic disease. Data were generated on familial frequencies and on the distribution of affected sibships by a two-allele single-locus model and the goodness of fit was tested hy a multifactorial model to the data and vice versa.
The singlelocus model is very flexible and can f i t multifactonal data well except when the frequency is very low and the heritability is high. The multifactorial model gives a poor fit in simple Mendelian-like situations, but the fit improves as the parameters of the singlelocus model become less Mendelian. In general it will be difficult to discriminate between models of inheritance with the types of data and forms of analyses studied. Even segregation analysis does not seem critical in discrimination, but ra!her serves to confirm the results derived from the familial frequency data. In practice, with sampling errors, ascertainment biases, mortality, variable onset age, heterogeneity, and many other complicating factors, discrimination between different modes of inheritance is likely to be very difficult indeed.     

Differences in cardio-respiratory responses to exhaustive exercise between athletes and non-athletes

Summary To study the factors limiting the O₂ supply in heavy exercise, O₂ uptake at exhaustion was determined by progressive loading method with a bicycle ergometer in 33 well-trained male runners and 34 male sedentary adults. Pulmonary ventilation, oxygen removal, respiratory rate, tidal volume, pulmonary diffusing capacity, alveolar-capillary oxygen difference, cardiac output, arterial-venous oxygen difference, stroke volume and heart rate were measured. It was found that pulmonary diffusing capacity, cardiac output and stroke volume were correlated with the difference in O₂ uptake at exhaustion between athletes and non-athletes.     

The divergence between two oncogenic Herpesvirus saimiri strains in a genomic region related to the transforming phenotype

Herpesvirus saimiri strains can be divided into at least three subgroups (A, B, C) based on sequence divergence at the left end of viral unique sequence DNA. Strains of subgroups A and C are highly oncogenic and readily transform simian T-lymphocytes in vitro to interleukin-2 independent growth, while subgroup B strains do not. A left terminal reading frame of a H. saimiri subgroup A strain was shown previously to correlate with the oncogenic phenotype and in vitro transforming potential; the deduced polypeptide was termed STP-A. Furthermore, this same region contains an open reading frame (ORF) for dihydrofolate reductase (DHFR) and genes for five virus-specific U RNAs (HSURs). We now show by sequence analysis of the corresponding region in a subgroup C strain that DHFR and HSUR genes are present in both virus subgroups; however, no sequence homologous to the STP-A reading frame was found in this subgroup C virus. At a position and orientation similar to STP-A, two ORFs were found for peptides sharing a putative transmembrane domain. One of them encodes a peptide with collagen-like repetitions. In addition to the lack of similarity to STP-A, these two reading frames also did not show any similarity to known oncogenes. The organization of sequences at the left junction of unique L- and repetitive H-DNA of H. saimiri suggests frequent recombinational events, possibly accelerating the uptake of foreign genes by the virus.     

Local high-frequency vibration therapy following eccentric exercises reduces muscle soreness perception and posture alterations in elite athletes

European Journal of Applied Physiology - Exercise-induced muscle damage produces painful sensations (delayed onset of muscle soreness, DOMS). DOMS causes compensatory postural adaptations, which in...     

Discriminating between first- and second-order cognition in first-episode paranoid schizophrenia*

Introduction: An impairment of visually perceiving backward masked stimuli is commonly observed in patients with schizophrenia, yet it is unclear whether this impairment is the result of a deficiency in first or higher order processing and for which subtypes of schizophrenia it is present.

Methods: Here, we compare identification (first order) and metacognitive (higher order) performance in a visual masking paradigm between a highly homogenous group of young first-episode patients diagnosed with paranoid schizophrenia (N?=?11) to that of carefully matched healthy controls (N?=?13).

Results: We find no difference across groups in first-order performance, but find a difference in metacognitive performance, particularly for stimuli with relatively high visibility.

Conclusions: These results indicate that the masking deficit is present in first-episode patients with paranoid schizophrenia, but that it is primarily an impairment of metacognition.     

The use of pupillometry in the assessment of cardiac autonomic function in elite different type trained athletes

The aim of the present study was to evaluate cardiac autonomic function by pupillometry in male athletes. Fifteen elite endurance- (END) and eleven power-trained (POWER) athletes and fifteen sedentary individuals (CONTROL) were studied. All subjects underwent three pupillometric measurements: at rest, peak exercise testing and recovery phase. The pupillometric indices studied were: baseline pupil radius (R1), minimum pupil radius (R2), maximum constriction velocity (VC_max), maximum constriction acceleration (AC_max), amplitude (AMP, R1–R2), constriction ratio (AMP%). During exercise, RR intervals were obtained for each subject with a Polar S810i for time and frequency domain heart rate variability (HRV) analysis. The following parameters of HRV were measured: standard deviation of all NN intervals (SDNN), the mean square successive differences (rMSSD), percent of NN intervals differing >50 ms from the preceding NN (pNN50), low (LF)- and high (HF)- frequency components of the autoregressive power spectrum of the NN intervals and their ratio (LF/HF). At rest and recovery, END showed significantly increased VC_max and AC_max compared to POWER and CONTROL. AMP% was significantly greater in END at rest, peak exercise and recovery compared to POWER and CONTROL. END and POWER had significantly greater AMP at rest and recovery compared to CONTROL. Moreover, all HRV indices were significantly increased in END compared to POWER and CONTROL. However, POWER showed significantly increased rMSSD and LF compared to CONTROL. HRV parameters were significantly correlated with pupillometric parameters during exercise. Our results indicated that any kind of exercise training and mainly endurance one affects autonomic regulation of pupillary light reflex.     

Neuromuscular and hormonal responses in elite athletes to two successive strength training sessions in one day

Summary Acute neuromuscular and endocrine adaptations to weight-lifting were investigated during two successive high intensity training sessions in the same day. Both the morning (I) (from 9.00 to 11.00 hours) and the afternoon (II) (from 15.00 hours to 17.00 hours) training sessions resulted in decreases in maximal isometric strength (p<0.01 and <0.05), shifts (worsening) in the force-time curve in the absolute scale (p<0.05 and ns.) and in decreases in the maximal integrated EMG (p<0.01 and <0.05) of the selected leg extensor muscles. Increases in serum total (p<0.05) and free testosterone (p<0.01) and in cortisol (p<0.01) concentrations were found during training session II. These were followed by decreases (p<0.001 andp<0.01 and ns.) in the levels of these hormones one hour after the termination of the session. The responses during the morning training session were different with regard to the decreases in serum total testosterone (p<0.05), free testosterone (ns.) and cortisol (p<0.05). Only slight changes were observed in the levels of luteinizing hormone and sex hormone-binding globulin during the training sessions. Increases (p<0.01) took place in somatotropin during both training sessions. The present findings suggest that high intensity strengthening exercises may result in acute adaptive responses in both the neuromuscular and endocrine systems. The diurnal variations may, however, partly mask the exercise-induced acute endocrinological adaptations in the morning. Recording of muscle activation and muscle strength and analysis of certain serum hormone concentrations with sufficient frequency during the training process may be useful in optimizing and controlling the contents of individual training sessions and the full training program.     

Body fat and blood lipids in postmenopausal women are related to resting autonomic nervous system activity

The present study investigated the activity of the autonomic nervous system (ANS), a major influence in normal physiological function, and its association with unfavorable postmenopausal states in body composition, lipid and/or glucose metabolism, or cardiovascular profiles. Body composition, blood pressure, and blood profiles of lipid and glucose of 175 postmenopausal women were measured. Resting ANS activity was assessed by heart rate variability (HRV) power spectral analysis. To scrutinize the influence of ANS activity levels on postmenopausal obesity-related factors, we divided the subjects into a low group ( < 220 ms²) and a high group ( > 220 ms²), based on the total power of HRV. Low-frequency (P < 0.01) and high-frequency power (P < 0.01) were both significantly lower in the low group. No significant difference was found in age, age at menopause, or years after menopause between the two groups. In contrast, body mass index (P < 0.05), percentages of body fat (P < 0.01), and systolic (P < 0.01) and diastolic (P < 0.01) blood pressure were significantly greater in the low group. As to blood lipid profiles, triglycerides (P < 0.05), total cholesterol (P < 0.05), and low-density lipoprotein cholesterol (P < 0.05) were significantly higher in the low group. Our findings indicate that reduced sympatho-vagal activity is associated with higher postmenopausal body fat content, blood pressure, and blood lipid concentrations. This study further implies that such autonomic depression could be a crucial risk factor in undermining the health and, ultimately, the quality of life, of postmenopausal women.