Relationships between measures of fitness, physical activity, body composition and vascular function in children

BACKGROUND

The prevalence of obesity and physical inactivity in Western countries has increased rapidly. Both are modifiable risk factors for cardiovascular disease. Atherosclerosis begins in childhood and endothelial dysfunction is its earliest detectable manifestation.

METHODS

We assessed flow-mediated dilation (FMD) in 129 children (75 female; 10.3+0.3 yrs; 54 male; 10.4; 0.3 yrs). FMD was normalised for differences in the eliciting shear rate stimulus between subjects (SR(AUC)). Fitness was assessed as peak oxygen uptake during an incremental treadmill exercise test (V O(2)peak). Body composition was measured using a dual-energy X-ray absorptiometry (DEXA) scan. Physical activity (PA) was assessed using Actigraph accelerometers. The cohort was split into tertiles according to FMD% and also FMD% corrected for SR(AUC) to gain insight into the determinants of vascular function.

RESULTS

Across the cohort, significant correlations were observed between FMD%/SR(AUC) and DEXA percentage fat (r=-0.23, p=0.009) and percentage lean mass (r=0.21, p=0.008), and also with PA performed at moderate-to-high intensity (r=0.363, p=0.001). For children in the lowest FMD%/SR(AUC) tertile, a stronger relationship with all PA measures was observed, particularly with high intensity PA (r=0.572, P=0.003). Regression analysis revealed that high intensity PA was the only predictor of impaired FMD%/SR(AUC).

CONCLUSIONS

These data suggest that traditional risk factors for CHD in adult populations impact upon vascular function in young people. Furthermore, it appears that individuals with impaired FMD may benefit from performing high intensity PA, whereas no relationships exist between FMD and lower intensities of PA or between PA and FMD in those subjects who possess preserved vascular function a priori.

Cross-sectional investigation of indices of isokinetic leg strength in youth soccer players and untrained individuals

In this cross-sectional study, the differences in the isokinetic peak torque of the knee joint muscles (dominant and non-dominant) were investigated in three groups of youths (n=45; age, 14.9+/-1.1 years) with different soccer training backgrounds. Significant main effects were observed for training background on the functional hamstrings to quadriceps ratios for knee flexion (H(CON):Q(ECC) ratio; F(2,42)=4.023, P=0.025) and extension (H(ECC):Q(CON) ratio; F(2,42)=8.53, P<0.001) at 4.32 rad/s. Post hoc tests indicated that both ratios were significantly different between conventionally trained players compared with resistance-trained players and controls (mean+/-SD; H(ECC):Q(CON) ratio, dominant limb; 0.91+/-0.10; 1.04+/-0.12; 1.10+/-0.22; non-dominant limb; 0.89+/-0.09; 1.05+/-0.19; 1.06+/-0.15; H(CON):Q(ECC) ratio, dominant limb; 0.36+/-0.06; 0.34+/-0.07; 0.30+/-0.08; non-dominant limb; 0.33+/-0.05; 0.32+/-0.08; 0.28+/-0.07). Results suggest that the muscle-loading patterns experienced in youth soccer may alter the reciprocal balance of strength about the knee under high-velocity conditions. The findings also indicate that these balances may be improved by incorporating resistance training into the habitual exercise routines of youth soccer players.

Post-mortem evidence of idiopathic left ventricular hypertrophy and idiopathic interstitial myocardial fibrosis: is exercise the cause?

A growing body of evidence reporting altered cardiac function and myocardial damage after arduous exercise, together with the increased prevalence of arrhythmias observed in highly trained athletes, suggests that repetitive bouts of prolonged, arduous exercise may be deleterious to long-term cardiac health. We report the case of an experienced, highly trained marathon runner who died suddenly while running. On post-mortem examination, left ventricle hypertrophy and idiopathic interstitial myocardial fibrosis was found. We believe that life-long, repetitive bouts of arduous physical activity resulted in fibrous replacement of the myocardium, causing a pathological substrate for the propagation of fatal arrhythmias.

Membranoproliferative glomerulonephritis with essential cryoglobulinemia

Cryoglobulinemia is an uncommon cause of renal disease and often occurs in patients with hepatitis C virus (HCV) infection. We report a case of membranoproliferative glomerulonephritis in a patient with cryoglobulinemia, which was not associated with HCV infection or any identifiable etiology.

Managing behavioural symptoms of dementia: effectiveness of staff education and peer support

This study was designed to investigate the impact of staff education on the behaviour and quality of life of residents with dementia and on staff members' attitudes about working with people with dementia and level of burnout. Staff from three aged care facilities participated in the study (n=52). These facilities were randomly assigned to one of two intervention groups or a control group. Staff assigned to the intervention groups received an eight-week behaviourally-based programme. Staff from one aged care facility also participated in a peer support group designed to reinforce educational material and facilitate positive changes among staff members. Behavioural symptoms displayed by residents (n=76) in each of the facilities were also assessed. Assessments were conducted at pre-intervention, post-intervention, three- and six-month follow-up. The results of this study indicated that education or peer support was not associated with an improvement in resident behaviour or quality of life. Education or peer support also did not impact on staff members' level of burnout. There was, however, a change in staff members' attitudes about working with people with dementia. Possible explanations for these findings and implication for further research are considered.

Effectiveness of staff training programs for behavioral problems among older people with dementia

This paper reviewed studies on staff training programs to address the behavioral problems associated with dementia among older people in residential care. The papers were classified according to whether or not the studies included a control group in the research design. The results of the review demonstrate that there has been a wide range of psychosocial and educational interventions to reduce behavioral problems among older people with dementia, with inconsistent results being obtained. However, many of these studies suffer from problems in their research design that make it difficult to evaluate their effectiveness. Problems in conducting research in the nursing home setting are highlighted, and suggestions for future research in this area are discussed.

Treat the patient not the blood test: the implications of an increase in cardiac troponin after prolonged endurance exercise

Collapse after prolonged endurance exercise is common and usually benign. This case study reports a triathlete who suffered a vaso-vagal associated collapsed after exercise. Misdiagnosis of myocardial injury in the presence of elevated cardiac troponins and ECG anomalies led to inappropriate management and highlights the difficulty in treating the collapsed athlete following arduous exercise.

The prevalence and recognition of major depression among low-level aged care residents with and without cognitive impairment

Previous research has demonstrated a high level of depression in nursing homes. The current study was designed to determine the prevalence of depression, using a structured diagnostic interview, among older people with and without mild-moderate cognitive impairment residing in low-level care facilities. The results demonstrated that, consistent with previous research in nursing homes, 16.9% of older people were diagnosed with major depressive disorder. Less than half of these cases had been detected or treated. Individuals with moderate cognitive impairment were more likely to be depressed, but cognitive impairment did not appear to act as a strong impediment to the detection of depression by general practitioners. A low awareness of their use of antidepressant medications was demonstrated among older people prescribed this treatment, including those with normal cognitive function. Reasons for the poor recognition of depression among older people are discussed.

Sex-specific influences of vasopressin on human social communication

Arginine vasopressin (AVP) and related peptides affect social behaviors in numerous species, but AVP influences on human social functions have not yet been established. Here, we describe how intranasal AVP administration differentially affects social communication in men and women, and we propose a mechanism through which it may exert those influences. In men, AVP stimulates agonistic facial motor patterns in response to the faces of unfamiliar men and decreases perceptions of the friendliness of those faces. In contrast, in women, AVP stimulates affiliative facial motor patterns in response to the faces of unfamiliar women and increases perceptions of the friendliness of those faces. AVP also affected autonomic responsiveness to threatening faces and increased anxiety, which may underlie both communication patterns by promoting different social strategies in stressful contexts in men and women.

Preload maintenance protects against a depression in left ventricular systolic, but not diastolic, function immediately after ultraendurance exercise

OBJECTIVE

To investigate indices of left ventricular (LV) function before and after a 224 km Ironman triathlon, specifically in the presence of unaltered haemodynamic loading.

METHOD

LV loading and function were assessed before and after the race using M mode and Doppler echocardiography in 39 (mean (SD) age 33 (8) years, body mass 77.6 (8.6) kg; 36 male) triathletes in the Trendelenburg position. Specifically left ventricular end diastolic volume (LVEDV) was assessed to estimate preload, and systolic blood pressure to estimate afterload as well as heart rate (HR). Systolic functional indices included ejection fraction (EF) and the end systolic pressure/volume ratio (ESPV), and diastolic functional indices included peak mitral flow velocity in early (E) and atrial (A) filling as well as the ratio E/A. Data obtained before and after the race were compared by t tests, and delta LV functional indices were correlated with delta heart rate.

RESULTS

Preload (LVEDV: 143 (34) ml before v 147 (34) ml after) and afterload (systolic blood pressure 121 (13) v 115 (20) mm Hg) were not significantly altered after the race (p>0.05), nor were EF (61 (8)% v 58 (10)%) and ESPV (2.4 (0.9) v 2.1 (0.8) mm Hg/cm(3)). The diastolic filling ratio E/A was significantly reduced after the race (1.73 (0.25) v 1.54 (0.23); p<0.05) due primarily to a reduction in E. HR was significantly higher after the race (57 (9) v 75 (8) beats/min; p<0.05), but delta HR was not related to delta E/A (p>0.05).

CONCLUSION

When preload and afterload are unaltered after the race, because of the adoption of a unique assessment posture, LV systolic function is not depressed. A depression in LV diastolic function persists which is not explained by an increase in heart rate after the race.

Solar disinfection of water for diarrhoeal prevention in southern India

AIMS

To evaluate the efficacy and acceptability of solar irradiation in the prevention of diarrhoeal morbidity in children under 5 years of age, in an urban slum in Vellore, Tamil Nadu.

METHODS

A total of 100 children were assigned to receive drinking water that had been subjected to solar disinfection in polyethylene terephthalate bottles. One hundred age and sex matched controls were also selected. Both groups were followed by weekly home visits for a period of six months for any diarrhoeal morbidity. At the end of the follow up period, the acceptability of the intervention was assessed by interviews, questionnaires, and focus group discussions.

RESULTS

There was significant reduction in the incidence, duration, and severity of diarrhoea in children receiving solar disinfected water, despite 86% of the children drinking water other than that treated by the intervention. The incidence of diarrhoea in the intervention group was 1.7 per child-year, and among controls 2.7 per child-year, with an incidence rate ratio of 0.64 (95% CI -0.48 to 0.86). The risk of diarrhoea was reduced by 40% by using solar disinfection. In qualitative evaluation of acceptability, most women felt that solar disinfection was a feasible and sustainable method of disinfecting water.

CONCLUSIONS

Solar disinfection of water is an inexpensive, effective, and acceptable method of increasing water safety in a resource limited environment, and can significantly decrease diarrhoeal morbidity in children.

Rates and factors associated with suicide in Kaniyambadi Block, Tamil Nadu, South India, 2000-2002

BACKGROUND

Inefficient civil registration systems, non-report of deaths, variable standards in certifying death and the legal and social consequences of suicide are major obstacles to investigating suicide in the developing world.

OBJECTIVE

The aim of this study was to prospectively determine the suicide rate in Kaniyambadi Block, Tamil Nadu, South India, for the years 2000-2002 using verbal autopsies.

METHOD

The setting for the study was a comprehensive community health programme in a development block in rural South India. The main outcome measure was death by suicide, diagnosed by a detailed verbal autopsy and census, and birth and death data to identify the population base.

RESULTS

The average suicide rate was 92.1 per 100,000. The ratio of male to female suicides was 1:0.66. The age-specific suicide rate for men increased with age while that for women showed two peaks: 15-24 years and over 65 years of age. Hanging (49%) and poisoning with organo-phosphorus compounds (40.5%) were the commonest methods of committing suicide. Acute and/or chronic stress was elicited for nearly all subjects. More men suffered from chronic stress while more women had acute precipitating events (chi2 = 4.58; p < 0.04). People less than 44 years of age had more acute precipitating events before death while older subjects reported more chronic stress (chi2 = 17.38; p < 0.001).

CONCLUSION

The study replicates findings of an earlier study from the area. The suicide rate documented in this study is very high and is a major public health concern. There is a need for sentinel centres in India and in developing countries to monitor trends and to develop innovative strategies to reduce deaths by suicide.

Chromosomes Lacking Telomeres are Present in the Progeny of Human Lymphocytes Exposed to Heavy Ions

High-charge and energy (HZE) nuclei represent one of the main health risks for human space exploration, yet little is known about the mechanisms responsible for the high biological effectiveness of these particles. We have used in situ hybridization probes for cross-species multicolor banding (RxFISH) in combination with telomere detection to compare yields of different types of chromosomal aberrations in the progeny of human peripheral blood lymphocytes exposed to either high-energy iron ions or gamma rays. Terminal deletions showed the greatest relative variation, with many more of these types of aberrations induced after exposure to accelerated iron ions (energy 1 GeV/nucleon) compared with the same dose of gamma rays. We found that truncated chromosomes without telomeres could be transmitted for at least three cell cycles after exposure and represented about 10% of all aberrations observed in the progeny of cells exposed to iron ions. On the other hand, the fraction of cells carrying stable, transmissible chromosomal aberrations was similar in the progeny of cells exposed to the same dose of densely or sparsely ionizing radiation. The results demonstrate that unrejoined chromosome breaks are an important component of aberration spectra produced by the exposure to HZE nuclei. This finding may well be related to the ability of such energetic particles to produce untoward late effects in irradiated organisms.

Cytogenetic effects of high-energy iron ions: dependence on shielding thickness and material

We report results for chromosomal aberrations in human peripheral blood lymphocytes after they were exposed to high-energy iron ions with or without shielding at the HIMAC, AGS and NSRL accelerators. Isolated lymphocytes were exposed to iron ions with energies between 200 and 5000 MeV/nucleon in the 0.1-1-Gy dose range. Shielding materials consisted of polyethylene, lucite (PMMA), carbon, aluminum and lead, with mass thickness ranging from 2 to 30 g/cm2. After exposure, lymphocytes were stimulated to grow in vitro, and chromosomes were prematurely condensed using a phosphatase inhibitor (calyculin A). Aberrations were scored using FISH painting. The yield of total interchromosomal exchanges (including dicentrics, translocations and complex rearrangements) increased linearly with dose or fluence in the range studied. Shielding decreased the effectiveness per unit dose of iron ions. The highest RBE value was measured with the 1 GeV/nucleon iron-ion beam at NSRL. However, the RBE for the induction of aberrations apparently is not well correlated with the mean LET. When shielding thickness was increased, the frequency of aberrations per particle incident on the shield increased for the 500 MeV/nucleon ions and decreased for the 1 GeV/nucleon ions. Maximum variation at equal mass thickness was obtained with light materials (polyethylene, carbon or PMMA). Variations in the yield of chromosomal aberrations per iron particle incident on the shield follow variations in the dose per incident particle behind the shield but can be modified by the different RBE of the mixed radiation field produced by nuclear fragmentation. The results suggest that shielding design models should be benchmarked using both physics and biological data.

Stability of chromosome aberrations in the blood lymphocytes of astronauts measured after space flight by FISH chromosome painting

Follow-up measurements of chromosome aberrations in the blood lymphocytes of astronauts were performed by FISH chromosome painting at various intervals from 5 months to more than 5 years after space flight and compared to preflight baseline measurements. For five of the six astronauts studied, the analysis of individual time courses for translocations revealed a temporal decline of yields with half-lives ranging from 10 to 58 months. The yield of exchanges remained unchanged for the sixth astronaut during an observation period of 5 months after flight. These results may indicate complications with the use of stable aberrations for retrospective dose reconstruction, and the differences in the decay time may reflect individual variability in risk from space radiation exposure.

Chest radiographs and their reliability in the diagnosis of tuberculosis

Radiology plays an important role in the diagnosis of pulmonary tuberculosis. Many medical practitioners believe in and rely primarily on the chest x-ray for the diagnosis of pulmonary tuberculosis. This study attempts to evaluate the reliability and validity of chest radiographs. This study was carried out in the tuberculosis clinic of BPKIHS. 75 radiographs were chosen for the study and viewed by 25 physicians of varying qualifications. Their findings were compared with the gold standard. The overall sensitivity and specificity was 78% and 51% respectively. There was poor agreement between the best physician and the best radiologist. This study has demonstrated an unsatisfactory sensitivity and specificity of chest x-rays in the diagnosis of pulmonary tuberculosis. The over-diagnosis and over-treatment due to chest x-rays could lead to an unmanageable burden on the resources of a poor country like Nepal. Private practitioners should be made aware about the importance of bacteriological diagnosis of tuberculosis before initiating drug therapy.