Hemostatic response to acute physical exercise in healthy adolescents

The chronic and immediate post-exercise responses in the hemostatic and fibrinolytic systems have been shown to be variable and reflect differing adaptations with ageing and responses to exercise protocols. This study investigated the effects of acute and exhaustive exercise on the amplitude and duration of hemostatic and fibrinolytic responses in young adolescent males. The sample comprised 10 sedentary boys (13.2+/-0.5 years, 55.8+/-11.3kg, 165.7+/-7.4cm), who had not exercised or received any medication for at least 2 weeks before the experiments. The subjects performed exhaustive stepping exercise, consisting of 1s up and down cycles to fatigue. When the subjects were unable to maintain the required stepping rhythm, they were given a 30s recovery period. Following each 30s recovery participants recommenced the stepping cadence until fatigue prevented them continuing. Venous blood samples were drawn before and immediately, 1 and 24h after exercise to assess the following coagulation and fibrinolytic parameters: Platelet counts, activated partial thromboplastin time (aPTT), prothrombin time (PT), coagulation factor VIII (FVIII:C), von Willebrand factor (vWF), fibrinogen concentration, thrombin-antithrombin complex (TAT), D-dimer, plasminogen activator inhibitor (PAI-1), and tissue-type plasminogen activator (t-PA). Immediately following exercise, platelet counts, aPTT, FVIII, vWF and t-PA were significantly elevated in contrast to PAI-1, which decreased significantly until 1h after exercise. FVIII and platelet counts were elevated at 1 and 24h after exercise, respectively. Only the parameters FVIII and PAI-1 did not return to baseline values during the first hour after physical exercise. When compared to adults the results revealed different rates and ranges of coagulation and fibrinolysis parameters being activated by exhaustive exercise in this group of adolescents.

Exhaustive exercise with high eccentric components induces prothrombotic and hypofibrinolytic responses in boys

It is known that coagulation and fibrinolysis are activated after exercise, and that the response is related to exercise intensity. The contribution, however, of eccentric exercise has not yet been investigated. Twenty boys (age 13 years) were randomly assigned to two experimental groups, which had to perform a monopedal stepping exercise until exhaustion. One group had to step up and down (U/D) in the same rhythm of one second each, while the other group (U/DD) had to step up during one second and to step down during two seconds, thereby experiencing a higher eccentric load. Blood samples were collected before and at 0, 1, and 24 hrs after exercise, and F VIII, t-PA, PAI-1, and D-dimer were determined as markers for coagulation or fibrinolysis, respectively. While the tendency for hypercoagulability was counterbalanced by fibrinolysis in the U/D group, the U/DD group showed a prothrombotic and hypofibrinolytic hemostatic response. It is assumed that eccentric exercise, beyond the well-known muscle fiber damage, also leads to some damage of the endothelial cells, affecting their capacity to liberate sufficient amounts of fibrinolytic agents.

Relationship between physical activity and obesity in children and adolescents

AIM

The purpose of the present study was to analyze the relationship between physical activity (PA) and obesity in Portuguese children and adolescents.

METHODS

The sample consisted of 1341 children and adolescents (8-15 years of age), 634 males (age, 10.6+/-2.3 y; body mass, 40.6+/-12.7 kg; height, 1.431+/-1.41 m) and 707 females (age, 10.9+/-2.4 y; body mass, 50+/-12.4 kg; height, 1.428+/-1.32 m). The sample was divided into quartiles of percentage of body fat (%BF) and physical activity index (PAI), within age and gender. Children in the upper %BF quartile were defined as obese (arbitrary definition). Logistic regression for each PAI quartile was used to determine the odds ratio of obese children and adolescents (> or = P75 of %BF) in comparison to their non-obese counterparts (< P75 of %BF).

RESULTS

Males in the lowest PAI quartile have an odds ratio of 2.1 of having obesity in relation to males in the highest PAI quartile. For females any significant result was found between PAI quartiles.

CONCLUSIONS

The results obtained in this study add some data to the controversy of PA and obesity relationship youth. Logistical regression shows that males who have a lower PAI have an odds ratio of 2.1 of obesity, in comparison with males that have higher PAI. Those findings were not found in girls.

Indoor physical education measured by heart rate monitor. A case study in Portugal

AIM

Reports indicated that children are spending too much time being physically inactive during physical education classes and many school physical education programs are not meeting the recommendation. The purpose of this study was to investigate the physical activity levels in Portuguese indoor physical education classes.

METHODS

The physical activity levels of 28 Portuguese 7th grade children were assessed by heart rate monitor during their indoor physical education classes.

RESULTS

The study showed that much physical education class time had been wasted, and less than 70% of physical education class time had actually been used in classes. On average, 14.4 minutes of 45-min physical education classes and 27.9 min of 90-min physical education classes had been spent in MVPA with children's heart rates above 139 bpm; 6.7 min of 45-min physical education classes and 15.7 min of 90-min physical education classes had been spent in VPA with children's heart rates above 159 bpm. Children engaged in more MVPA, VPA, and continuous bouts of physical activity in 90-min physical education classes than those of 45-min physical education classes. There were no significant differences in activity levels between genders in co-educational indoor physical education classes.

CONCLUSIONS

This indoor PE class study supports the results that children are less active during school physical education classes. Both the quantity and the quality of school physical education needs to improve to encourage children to engage in a substantial amount of physical activity both inside and outside school.

Overweight and obesity in children and adolescents: relationship with blood pressure, and physical activity

OBJECTIVE

Using body mass index (BMI) quartiles, the present study's aims were (1) to describe and evaluate the relationship between overweight/obesity with cardiovascular disease (CVD) risk factors, such as systolic blood pressure (SBP), diastolic blood pressure (DBP) and physical activity; (2) to provide information on the prevalence of high blood pressure and physical activity according to BMI quartiles; and (3) to examine the relationship of risk of obesity to adverse levels of high blood pressure and physical activity.

METHODS

The sample consisted of 1439 children (758 males and 681 females), 8-16 years old. Participants were classified as being at 'risk of obesity' according to age- and sex-adjusted fourth quartile of BMI values. Blood pressure was measured using the Dinamap monitor. An adapted version of the Weekly Activity Checklist was applied for the diagnosis of physical activity index (PAI).

RESULTS

Systolic and diastolic blood pressures were significantly (p < 0.05) and positively related to BMI, whereas no significant associations were reported between BMI and PAI in both genders. Overall, the proportion of subjects with adverse levels of blood pressure (SBP or DBP) ranged from 21.3% in the first BMI quartile (BMI-1Q) to 30.4% in BMI-4Q (p < 0.05). The PAI ranged from 24.5% in BMI-1Q to 20.6 in BMI-4Q and no significant differences were found. Children and adolescents at 'risk of obesity' were 1.5 times as likely to have at least one risk factor (high blood pressure or low level of activity).

CONCLUSIONS

Our data suggest that higher BMI is associated with higher values of SBP and DBP. Children and adolescents in the upper quartile of BMI are 1.5 times as likely to have at least one risk factor. Furthermore our data confirmed previous findings that higher levels of BMI are associated with a unfavourable risk profile for CVD risk factors.

Age and gender-related physical activity. A descriptive study in children using accelerometry

AIM

Precise measures of habitual physical activity are necessary in studies designed to: 1) document the frequency and distribution of physical activity in defined population groups; 2) determine the amount or dose of physical activity requires to influence specific health parameters. The purpose of this study was to document the age and gender-related physical activity levels on a sample of school children.

METHODS

The sample for the present study comprised 157 children (boys n=64 and girls n=93), aged 8 to 15 years-old. The CSA activity monitor was used as an objective measure of daily physical activity. Each student in the present study was scheduled to wear the CSA 3 times during the week of monitoring.

RESULTS

Boys were involved (p=/<0.05) in more time MVPA than girls. However only in the 11-13 year old group were found significant differences (p=/<0.05). Within gender, significant differences were found out among 11-13 years old (48.7 min) and 14-16 years (72.2 min). The time in MVPA increased across age group in both males and females. Boys participated in more periods of continuous physical activity, bouts of 10 and 20 min respectively, than girls. However no significant differences were found out.

CONCLUSION

Our data showed that children under observation, excepted girls in the 11-13 year old group, appear to meet the minimum physical activity level recommended for health. The data also suggested that boys are more active than girls are and that they were significantly more engaged in more time MVPA than girls did. Surprisingly our data showed an increase in MVPA time as age increases. Further studies are needed to compare the different cut off points assessed during daily activity.

Relationship between cardiorespiratory fitness, body composition and blood pressure in school children

BACKGROUND

The purpose of this comparative and correlational cross-sectional study was to describe the associations between cardiorespiratory fitness, blood pressure and body composition in Portuguese school children.

METHODS

The sample comprised 529 children (246 males and 283 females) aged 8-15 years-old. Body height and body mass were determined by standard anthropometric

METHODS

Blood pressures were measured with children sitting after at least 5 min rest. The maximal multistage 20 m shuttle run test was carried-out to predict maximal aerobic power.

RESULTS

The present study shows that boys were more fit (p= or <0.05) and less fat than girls (p= or <0.05). Multiple regression analysis reveals that weight and age explained significantly (p= or <0.01) the amounts of systolic blood pressure (SBP) and diastolic blood pressure (DBP). In girls, percentage of fat (%F) showed an influence on the variance in SBP (4.9%, p= or <0.05). In addition, weight (14.5%) and age (9.8%) account significantly (p= or <0.01) for the amount of variance to DBP in males. For girls, age (11.4%) and BMI (2.4%) account significantly to the variance found in DBP. However, the independent variables, for both sexes, account less than 50% of the overall variance found in blood pressures values.

CONCLUSIONS

In conclusion, the present study shows that boys were more fit and had less fat than girls. The level of cardiorespiratory fitness does not seem to be an important correlate of blood pressure variation across age groups and gender.

[Development of immunizing agents against dengue]

The four serotypes of dengue flaviviruses are transmitted mainly by the Aedes aegypti mosquito, and some epidemics have been attributed to Ae. albopictus, Ae. polynesiensis, and various species of the Ae. scutellaris complex. The risk factors involved in dengue mortality and morbidity are related to the human host (genetic characteristics of infected persons; lifestyles, immune status, and health conditions of people; basic sanitation of dwellings; and water supply) and to the virus (genetic variability between and among serotypes, different pathogenicities, and geographic distribution). Notwithstanding the lack of knowledge of the immunopathobiology of dengue fever, important advances have been made in terms of a protective immune response, using attenuated dengue viruses or antigens produced by means of recombinant technologies. Efforts have been made since the 1940s to develop dengue vaccines. Immunity acquired from natural infection is specific for each serotype, and as many as three different serotype infections have been reported in one individual. For this reason, a tetravalent vaccine may likely be needed. Candidate vaccines against the four serotypes have been tested in volunteers and have proven to be immunogenic and safe. Although attenuated live virus vaccines are promising, more study is needed regarding their effectiveness and safety. Currently, several studies are ongoing to develop dengue vaccines using antigens from structural proteins (particularly E glycoprotein) and nonstructural proteins, with recombinant DNA technology and other biomolecular technologies. With the same goal, various expression vectors are being used, including Escherichia coli, baculovirus, vaccinia virus, and yellow fever virus. Unfortunately, no satisfactory results have been obtained in humans. The need for effective dengue vaccines is great, given the serious worldwide problem of the transmission of the four serotypes. Effective immunization against dengue would contribute to its prevention, with a positive cost-benefit relationship. Endemic dengue affects young children, and they should be immunized through the Expanded Program on Immunization.

Superior labrum anterior-posterior lesions: diagnosis with MR arthrography of the shoulder

PURPOSE

To determine the accuracy of magnetic resonance (MR) arthrography in the diagnosis of superior labrum anterior-posterior (SLAP) lesions of the shoulder.

MATERIALS AND METHODS

From January 1995 to June 1998, MR arthrography of the shoulder was performed in 159 patients with a history of chronic shoulder pain or instability. Fifty-two patients underwent arthroscopy or open surgery 12 days to 5 months after MR arthrography. Diagnostic criteria for SLAP lesion included marked fraying of the articular aspect of the labrum, biceps anchor avulsion, inferiorly displaced bucket handle fragment, and extension of the tear into the biceps tendon fibers. Surgical findings were correlated with those from MR arthrography.

RESULTS

SLAP injuries were diagnosed at surgery in 19 of the 52 patients (37%). Six of the 19 lesions (32%) were classified as type I, nine (47%) as type II, one (5%) as type III, and three (16%) as type IV. MR arthrography had a sensitivity of 89% (17 of 19 patients), a specificity of 91% (30 of 33 patients), and an accuracy of 90% (47 of 52 patients). The MR arthrographic classification showed correlation with the arthroscopic or surgical classification in 13 of 17 patients (76%) in whom SLAP lesions were diagnosed at MR arthrography.

CONCLUSION

MR arthrography is a useful and accurate technique in the diagnosis of SLAP lesions of the shoulder. MR arthrography provides pertinent preoperative information with regard to the exact location of tears and grade of involvement of the biceps tendon.

Systemic mastocytosis: MRI of bone marrow involvement

Systemic mastocytosis (SM) is an abnormal proliferation of mast cells, located in different structures: skin, bone marrow, spleen, liver and lymph nodes. Magnetic resonance imaging was prospectively performed in ten patients diagnosed by bone marrow biopsy in order to describe the different patterns of bone marrow involvement. Coronal T1-weighted spin-echo images were obtained in vertebral, pelvic, humeral and femoral bones. Depending on the extension of the cell infiltration, three patterns of bone marrow involvement were used: normal/no involvement (N), non-homogeneous (NH) and homogeneous (H). All ten patients presented bone infiltration. The patterns observed were: spine (50 % NH, 50 % H), pelvis (70 % NH), humerus 100(NH) and femur 40 % (NH). T1-weighted MR imaging is a sensitive technique for detecting marrow abnormalities in patients with systemic mastocytosis. There is no correlation between percentage of mast cells in bone marrow biopsy and extent or pattern of bone marrow involvement.

Magnetic resonance imaging of the peroneal tendons

Injuries of the peroneal tendons include tendinosis, tenosynovitis, tears, and dislocation. These injuries are being detected with greater frequency since the advent of MRI. After a review of the normal MRI anatomy of the peroneal tendons, this article will focus on the MR features of peroneal tendon disorders in the foot and ankle.

Dengue virus in the brain of a fatal case of hemorrhagic dengue fever

Neurologic complications associated with dengue fever are in general unusual. However, recent reports evidence more frequent neurologic alterations. In Mexico, neurologic involvement has not been reported in dengue cases. This report demonstrates the detection of dengue virus in the brain of a fatal case of dengue hemorrhagic fever. Serotype 4 was detected by immunohistochemistry and by RT-PCR in the inferior olivary nucleus of medulla and in the granular layer of cerebellum. Immunoreactivity was observed in neurons, astrocytes, microglia and endothelial cells. Our results emphasize the importance of neurologic manifestations in patients with dengue fever.

Quantitative measurements of the spinal cord and canal by MR imaging and myelography

There is a large individual variation in human spinal cord and canal size, even in patients of different series studied by the same modality, and no authorized standard method has been established. A comparative study of sagittal diameters of the cervical spinal cord and canal using myelography and MRI is presented. The purposes of this paper are (a) to establish the correction factor (CF) needed for quantitative comparison of the two imaging modalities, and (b) to determine the different factors that may modify the measurement of these diameters. We studied 45 patients with clinical findings compatible with cervical spondilotic myelopathy. In our experience, the CF for accurate correlation of MRI and myelography measurements is 1.32 and depends almost entirely on the radiographic geometry of the myelographic procedure. In addition, there is a variability in the group of MRI results due to imprecision of the pressure-pad measuring/input device of the instrument itself and the sequence performed.

Spontaneous enterourachocutaneous fistula in Crohn's disease: sonographic diagnosis

Spontaneous abdominal wall fistulas are rare in Crohn's disease. We report a case of enterourachocutaneous fistula in a woman with Crohn's disease and present the sonographic, computed tomographic, and sinographic findings.

[Magnetic resonance in the diagnosis of extent and osseous complications of Gaucher's disease type 1]

OBJECTIVE

To evaluate the usefulness of magnetic resonance (MR) for investigating bone involvement in Gaucher disease type 1 (GD).

METHODS

Ten adult patients with the diagnosis of GD type 1 were studied. Weighted sequences were performed in spin-echo (SE) T1 and T2 of 4 body areas: spine, pelvis, hips, and femurs. The patterns of bone infiltration proposed for the study were: homogeneous infiltration (H), non-homogeneous infiltration (NH), and normality (N). Four patients were receiving enzyme replacement therapy.

RESULTS

All patients (100%) showed changes associated with infiltration with Gaucher cells. The distribution of patterns was as follows: the homogeneous pattern predominated (60 and 50%, respectively) in spine (6H/2NH/2N) and pelvis (5H/3NH/2N), whereas the non-homogeneous pattern predominated (60% and 80%, respectively) in hips (1H/6NH/3N) and femurs (1H/8NH/1N). As bone complications two cases of hip avascular necrosis were noted, one of them with bilateral involvement, one case with infarcts in femur diaphysis and other case with medullar edema in a bone crisis.

CONCLUSION

MR is an excellent technique for detecting medullar bone infiltration and complications in GD type 1.

[Magnetic resonance imaging usefulness in the diagnosis of intratumor bleeding in hypophyseal adenomas]

Hypophyseal adenomas are the most frequent intrasella tumours. They are classified as macroadenomas or as microadenomas depending on whether their size is greater or less than 1 cm. Hypophyseal tumours may undergo ischaemic necrosis and haemorrhage when the blood supply is reduced. Intratumoural bleeding is found in varying percentages, between 9.9% and 26%. We review our series of 122 patients with hypophyseal adenomas in whom MR was done. Signs of bleeding were found in 12 patients (9%). In five cases, bleeding had presented as hypophyseal apoplexy, in five cases with subacute symptoms and in two cases was asymptomatic and diagnosis fortuitous. Of the adenomas with intratumoural bleeding, 9 were functioning tumours (4 secreted PRL, 4 ACTH and 1 GH) and 3 non-functioning. The risk factors considered in the pathogenesis of intratumoural bleeding are numerous. The increased incidence of bleeding in large and in invasisve adenomas, especially when treated with bromocriptin, is well established. MR is the ideal technique to detect intratumoural bleeding, T2 weighted sequences being very useful in the diagnosis of bleeding in the acute phase. In the subacute phase, focal areas of hyperintensity are seen in T1 and of hypo/hyperintensity in T2. In the chronic phase, areas of hypodensity are seen both in T1 and in T2. In our study we analyze the clinico-radiological correlation in patients with signs of intratumoural bleeding.