Arteriovenous malformation of the whole small bowel--a therapeutic dilemma.
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Adult↗
Biomedical subjects
A Belli
Publications and source records attributed to A Belli.
Leg stiffness and foot orientations during running.
This study was done to determine whether leg stiffness (Kleg) during running was related to rearfoot-to-forefoot angle in standing (RFAst) and running (RFArun). Footprints obtained from 32 subjects were used to calculate RFAst and RFArun, defined as positive when forefoot axis was abducted from rearfoot axis. A spring-mass model was used to calculate Kleg in running from ground reaction forces, measured by a force platform. The Kleg of runners (13.0 +/- 2.7 kN x m(-1)) was negatively correlated with RFAst (-8.4 degrees +/- 6.4 degrees) and RFArun (-0.4 degrees +/- 7.2 degrees). When runners were divided into opened foot (RFArun > 0; N = 19) and closed foot (RFArun < 0; N = 12) groups, the Kleg of opened foot runners was less than that of the closed runners. We suggest that foot structure is a factor responsible for the differences in leg stiffness observed in runners.
Adult↗
Simplified polymerase chain reaction detection of new world Leishmania in clinical specimens of cutaneous leishmaniasis.
Polymerase chain reaction (PCR)-based detection of New World Leishmania from different types of clinical specimens has been further streamlined for field use by simplifying sample preparation and modifying published protocols. A multiplex PCR reaction was developed that allows simultaneous detection of the Leishmania genus and identification of the L. braziliensis complex. For typing isolates in culture, we found that simply boiling diluted cultured strains was sufficient preparation for the PCR. We have demonstrated that Leishmania parasites can be reliably detected from boiled dermal scrapings, instead of the more invasive skin biopsies often used as PCR specimens. The PCR of dermal scrapings yielded a sensitivity of 100% and a specificity of 100%, as compared with microscopic examination. In a study population, PCR was more sensitive than classic diagnostic techniques. The PCR detection of Leishmania in biopsies and peripheral blood mononuclear cells (PBMCs) was investigated. Diluting crude extracts of skin biopsies was sufficient to eliminate sample inhibition yet maintain required sensitivity. Leishmania braziliensis was also detected by PCR in PBMCs of individuals with active cutaneous leishmaniasis. The simplifications described here significantly improve the feasibility of using the PCR in endemic countries as the primary method for detection and preliminary characterization of Leishmania in clinical specimens of cutaneous leishmaniasis.
Animals↗
Habitual physical activity and peak anaerobic power in elderly women.
The aim of this study was to investigate the relationship between maximal anaerobic power (Pmax) and corresponding optimal velocity (Vopt) and habitual physical activity (PA) on the one hand and with maximal oxygen consumption (VO2max) on the other hand, in elderly women. Twenty-nine community dwelling, healthy women aged 66-82 years participated in the study. PA was evaluated using the Questionnaire d'Activite Physique Saint-Etienne (QAPSE) and expressed using two QAPSE activity indices: mean habitual daily energy expenditure (MHDEE) and daily energy expenditure corresponding to leisure time sports activities (sports activity). The subjects' Pmax and Vopt were measured while they cycled on a friction-loaded non-isokinetic cycle ergometer. Pmax was expressed relative to body mass [Pmax/kg(W.kg-1)], and relative to the mass of two quadriceps muscles [Pmax/Quadr(W.kg-1Quadr)]. A negative relationship between Pmax/kg (Spearman's r = -0.56; P < 0.01), Pmax/Quadr (r = -0.53; P < 0.01) and Vopt (r = -0.45; P < 0.05) and age was found. Pmax/kg was positively associated with MHDEE (r = 0.51; P < 0.01) and sports activity (r = 0.58; P < 0.01), as were Pmax/Quadr and Vopt (r = 0.55; P < 0.01 and r = 0.54; P < 0.01, respectively). Pmax/kg, Pmax/Quadr and Vopt correlated positively with VO2max. The positive relationship between ergometer measurements and PA indices was similar to that between VO2max and PA. Pmax/kg was, moreover, closely related to Vopt (r = 0.77; P < 0.001). When a multiple stepwise regression analysis was used to select the variables influencing ergometer measurements, MHDEE contributed significantly to Pmax/kg variance, whereas sports activity contributed to Pmax/Quadr and Vopt variances. In conclusion, the data from this cross-sectional study suggest that in healthy elderly women habitual PA, and especially leisure time PA, alleviates the decline of the Pmax of the quadriceps muscles.
Aged↗
Lactate exchange and removal abilities in rowing performance.
The relationships between individual performance and lactate exchange and removal abilities were studies in 12 male rowers all subjected to three measurements on a rowing ergometer. An incremental exercise carried out to determine the maximal oxygen uptake (VO2max) and the corresponding maximal aerobic power (Pamax), a 2500-m all-out test where the mean work rate (P2500) represented the individual performance, and a 6-min 90% Pamax exercise designed to assess the lactate kinetics during the following 90 min passive recovery were performed. The lactate recovery curves were fitted to the bi-exponential time function: La(t) = La(O) + A1(1-e-gamma 1.t) + A2(1-e-gamma 2.t). The velocity constants gamma 1 and gamma 2 denote the lactate exchange and removal abilities, respectively. The mean value of P2500 sustained by the rowers was 376 +/- 41W (106 +/- 5% of Pamax (P2500%). P2500 was positively correlated with gamma 2 (P < 0.05). gamma 1 and gamma 2 explained 67% of the P2500 variance. P2500% was also correlated with gamma 2 (P < 0.01). These results suggest that a better performance on the rowing ergometer is associated with improved lactate exchange and removal abilities. Furthermore, the ability to row at high relative work rates was correlated with an increased lactate removal ability. Training-induced adaptations could explain the high gamma 1 and gamma 2 displayed by the present rowers.
Adaptation, Physiological↗
Foot orientation and lower limb kinematics during running.
The purpose of this study was to determine the possible mechanisms explaining the interindividual differences in foot orientations observed during running. Foot orientations, foot pressures, and ankle dorsiflexion and plantarflexion were simultaneously recorded on 12 male subjects running barefooted at 3.9 +/- 0.6 m.sec-1. The abduction of the forefoot was significantly related to the ankle dorsiflexion and plantarflexion velocities (P < 0.01 and P < 0.05, respectively). Because it was not possible, from pressure measurements, to determine differences in foot lever arm of runners, it is suggested that the interindividual variability of foot kinematics could not be explained by Bojsen-Møller's model, but could reflect differences in the lower limb stiffness control.
Ankle↗
Experimental model of asymmetric brain ischemia and reperfusion in the rat.
BACKGROUND: In this experimental study is illustrated an original model of cerebral asymmetric ischemia and reperfusion in the rat, induced by unilaterally elevating ICP and clamping the corresponding common carotid artery, that allows a direct comparison of the two brain hemispheres, one normal and the other ischemic, of the same animal. METHODS: The experimental procedure consisted in grafting two screws through the skull on the right side of the sagittal suture, one of them being connected to a Queckenstedt manometer for monitoring ICP variations. A nitroprusside solution (1 mg/ml administered through the femoral vein at a flow rate of 0.103 ml/min) was infused to achieve a significant drop of MABP. At this time point, animals were subjected to 5 min of ischemia and 10 min of reperfusion induced by clamping and declamping the right common carotid artery. During the whole period of ischemia and reperfusion ICP and MABP were constantly monitored. In order to provide an outlook on the metabolic alterations of brain tissue occurring during ischemia and reperfusion phenomena, several biochemical parameters of cellular energy metabolism and of oxygen radical-induced membrane damage were determined by a sensitive and reproducible HPLC method on perchloric acid tissue extracts. RESULTS AND CONCLUSIONS: The validity of the present model was supported by the finding of significant intrahemispheric differences in the concentration of several compounds considered as biochemical markers of tissue injury, such as adenosine 5'-triphosphate catabolites and malondialdehyde, this last indicating the damaging action of oxygen free radicals on cell membrane phospholipids.
Animals↗
Activated protein C resistance due to a factor V mutation associated with familial ischemic stroke.
Recent findings have indicated the association between activated protein C (APC)-resistance and cerebrovascular disease. These reports prompted us to investigate whether resistance to APC could be found in patients suffering from transient ischaemic attacks or stroke. Therefore, we studied APC-resistance in 14 young adults belonging to three different families with a history of transient ischemic attacks (TIAs) and stroke. Nine out of fourteen subjects showed APC-resistance but no deficiencies in the anticoagulant proteins AT III, PC and PS. The family history demonstrated a distribution of APC-resistance compatible with dominant autosomal inheritance. A rapid screening method to detect factor V R506Q (Leiden) mutation without sequencing or restriction enzyme digestion has been set-up after biochemical analyses. DNA analysis showed a guanine to adenine transition at nucleotide 1,691 in patients and their relatives with poor response to activated protein C detected by APTT tests. Of 14 investigated subjects and their family members, 5 were normals, 6 were heterozygotes and 3 were homozygotes for factor V mutation. The mutation, in heterozygous form, was also found in 1.3% of our normal population (n = 75). Our findings indicate a possible involvement of APC-resistance in the pathogenesis of arterial thrombosis in young adults.
Adult↗
Muscle function during brief maximal exercise: accurate measurements on a friction-loaded cycle ergometer.
A friction loaded cycle ergometer was instrumented with a strain gauge and an incremental encoder to obtain accurate measurement of human mechanical work output during the acceleration phase of a cycling sprint. This device was used to characterise muscle function in a group of 15 well-trained male subjects, asked to perform six short maximal sprints on the cycle against a constant friction load. Friction loads were successively set at 0.25, 0.35, 0.45, 0.55, 0.65 and 0.75 N.kg-1 body mass. Since the sprints were performed from a standing start, and since the acceleration was not restricted, the greatest attention was paid to the measurement of the acceleration balancing load due to flywheel inertia. Instantaneous pedalling velocity (v) and power output (P) were calculated each 5 ms and then averaged over each downstroke period so that each pedal downstroke provided a combination of v, force and P. Since an 8-s acceleration phase was composed of about 21 to 34 pedal downstrokes, this many v-P combinations were obtained amounting to 137-180 v-P combinations for all six friction loads in one individual, over the widest functional range of pedalling velocities (17-214 rpm). Thus, the individual's muscle function was characterised by the v-P relationships obtained during the six acceleration phases of the six sprints. An important finding of the present study was a strong linear relationship between individual optimal velocity (vopt) and individual maximal power output (Pmax) (n = 15, r = 0.95, P < 0.001) which has never been observed before. Since vopt has been demonstrated to be related to human fibre type composition both vopt, Pmax and their inter-relationship could represent a major feature in characterising muscle function in maximal unrestricted exercise. It is suggested that the present method is well suited to such analyses.
Acceleration↗
Optimal velocity for maximal power production in non-isokinetic cycling is related to muscle fibre type composition.
To determine whether power-velocity relationships obtained on a nonisokinetic cycle ergometer could be related to muscle fibre type composition, ten healthy specifically trained subjects (eight men and two women) performed brief periods of maximal cycling on a friction loaded cycle ergometer. Frictional force and flywheel velocity were recorded at a sampling frequency of 200 Hz. Power output was computed as the product of velocity and inertial plus frictional forces. Force, velocity and power were averaged over each down stroke. Muscle fibre content was determined by biopsy of the vastus lateralis muscle. Maximal down stroke power [14.36 (SD 2.37)W.kg-1] and velocity at maximal power [120 (SD 8) rpm] were in accordance with previous results obtained on an isokinetic cycle ergometer. The proportion of fast twitch fibres expressed in terms of cross sectional area was related to optimal velocity (r = 0.88, P < 0.001), to squat jump performance (r = 0.78, P < 0.01) and tended to be related to maximal power expressed per kilogram of body mass (r = 0.60, P = 0.06). Squat jump performance was also related to cycling maximal power. expressed per kilogram of body mass (r = 0.87, P < 0.01) and to optimal velocity (r = 0.86, P < 0.01). All these data suggest that the nonisokinetic cycle ergometer is a good tool with which to evaluate the relative contribution of type II fibres to maximal power output. Furthermore, the strong correlation obtained demonstrated that optimal velocity, when related to training status, would appear to be the most accurate parameter to explore the fibre composition of the knee extensor muscle.
Adult↗
Optic fibre as a transducer of tendomuscular forces.
Direct in vivo tendon force measurements open up new possibilities for understanding of muscle-tendon loads during natural locomotion. The present report presents a new optic fibre method for such applications. The method is based on light intensity modulation by mechanical modification of the geometric properties of the optic fibre. A special optic fibre with a plastic covering buffer and with a total diameter of either 265 microns or 500 microns was carefully prepared at both ends for receiving and transmitting light. The fibre was inserted through the rabbit common calcaneal tendon with a 20 gauge needle. By removing the needle the optic fibre remained in situ. Static loading demonstrated that the voltage output of the optic fibre transducer showed a good linear fit of r = .999 with added loads. In dynamic loading conditions the optic fibre followed well the response of a strain gauge transducer, which was also attached to the tendon. The optic fibre method seems suitable for many applications for tensile and possibly ligament force measurements.
Animals↗
Relationship between rearfoot and forefoot orientation and ground reaction forces during running.
In this study, footprint and ground reaction forces (GRF) were simultaneously recorded from 32 male subjects running barefoot. Angle between the rearfoot and the forefoot in static (alpha S) and in running (alpha R) conditions, and orientation of both, rearfoot (alpha rf) and forefoot (alpha ff) with the direction of running (DOR), were measured and correlated to selected GRF parameters. The dynamic rearfoot/forefoot angle (alpha R) was correlated, positively with arch deformation (r = 0.58, P < 0.001), vertical Fz loading peak (r = 0.60, P < 0.001), mediolateral, and anteroposterior force rates (r = 0.47 and 0.48, P < 0.01), and negatively with stance time (r = -0.41, P < 0.05) and total course of the force application point path (r = -0.71, P < 0.001). Both a medial and a lateral rotation were observed on footprint between the rearfoot and the forefoot in the horizontal plane. A medially rotated forefoot ("closed foot") was associated to a rigid and inverted foot, whereas a laterally rotated forefoot ("open foot") was associated to a flexible and everted foot.
Adult↗
Resistance to activated protein C in adults with a history of juvenile transient ischemic attacks.
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Adult↗
Familial coagulation-inhibiting and fibrinolytic protein deficiencies in juvenile transient ischaemic attacks.
The aim of this study was to investigate the role of natural cascade inhibitors in Juvenile Transient Ischemic Attacks. Fifty patients with anterior or posterior brain attacks were studied. One hundred healthy subjects matched for sex and age were randomly assigned to a control group. All had a physical examination and radiologic work-up. Computerized tomography showed no ischaemia either with or without contrast medium. Digital angiography of epiaortic and intracerebral vessels was unremarkable patients non controls ever had war-farin therapy. Antithrombin III, protein C and plasminogen were determined by functional methods. Protein S was assayed by a functional clotting method based on prolonged PT. The activated protein C resistance test was performed and a poor response to activated protein C was verified in patients. Our findings show protein S, protein C and antithrombin III type I deficiency with a functional activity < 70% compared to controls. Eight of fifty patients (16%) had low protein S levels, 5 (10%) had low protein C, 2 (4%) had low antithrombin III and 1 (2%) plasminogen deficiency. A significant (p < 0.01) difference in activated protein C ratio was seen for controls and patients. These results suggest that screening for natural anticoagulants in young people suffering from transient ischemic attacks could be beneficial and should be encouraged.
Adult↗
[Evaluation of N-acetyl-beta glucosaminidase in upper and lower urinary tract infections in childhood. Clinical study of 168 children].
BACKGROUND: Urinary N-acetyl-beta-glucosaminidase (NAG) is a renal tubular enzyme that may be used as a marker of tubular damage. METHODS: We studied 96 patients 1 to 8 years old and considered NAG excretion to distinguish cystitis from pyelonephritis. Whenever urinary NAG values were expressed in relation to urinary creatinine concentration and compared with urinary NAG values in 72 normal controls 1 to 14 years old grouped by age. RESULTS: Our results demonstrate that urinary NAG levels are elevated in children with pyelonephritis in the presence or absence of urinary tract abnormality. CONCLUSIONS: Therefore, we conclude that NAG may be considered as a further criteria in the diagnosis of upper urinary tract infection and interstitial tubular damage.
Acetylglucosaminidase↗
A dynamometer for evaluation of dynamic muscle work.
The validation of a new dynamometer for evaluation of dynamic muscle work is presented. The device was based on a precise measurement of load displacements of any machine using gravitational loads as external resistance. It allowed, through a sensor consisting of an infrared photo interrupter, the calculation of velocity, force and power during concentric, eccentric and stretch-shortening cycle activity. To validate the dynamometer 33 male and female track and field athletes (12 throwers and 21 jumpers) participated in the study. The throwers (4 women and 8 men) were asked to perform half-squat exercises on a slide machine with a load of 100% of the subject's body mass. The day-to-day reproducibility of half-squat exercises gave a correlation coefficient of r = 0.88, 0.97 and 0.95 for average push-off force (AF), average push-off velocity (AV), and average push-off power (AP) respectively. Comparison of half-squat measurements was performed against jumping and running test evaluation by the jumpers (7 women and 14 men). The interrelationships among the different variables studied demonstrated a strong correlation between AF, AV and AP and sprinting and jumping parameters (r = 0.53-0.97; P < 0.05-0.001). Using values of AF, AV and AP developed in half-squat exercises executed with different loads, ranging from 35% to 210% of the subject's body mass, it was also possible to establish the force-velocity and power-velocity relationships for both male and female jumpers. In any individual case, the maximal error due to the measurement system was calculated to be less than 0.3%, 0.9% and 1.2% for AF, AV, and AP respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Mechanical step variability during treadmill running.
The present study was designed to study intra-individual step variability measured both on vertical displacement of the body (delta Z) and on step time (delta t) parameters by means of a kinematic arm and during treadmill running. A group of 17 subjects ran successively at 60%, 80%, 100% and 140% of their maximal aerobic velocity (Vamax). The total number of steps analysed was 6116. The absolute delta Z step variability (sigma delta Z) ranged between 5 mm and 21 mm while the absolute delta t variability (sigma delta t) ranged between 6 ms and 40 ms. Step variabilities were due to step asymmetry (from 38.5% to 48.5% of the step variability) and to stride variability. For submaximal velocities (60%, 80%, and 100% Vamax) both sigma delta t and sigma delta Z were independent of velocity or body dimensions whereas differences between subjects were significant (P < 0.01) for sigma delta Z. On the other hand, variabilities were significantly increased when velocity was changed from submaximal to the 140% Vamax level. Furthermore, at submaximal levels sigma delta Z was linked to the subject's energy cost of running (P < 0.05). Therefore, the intra-individual step variability should not be neglected in future studies on mechanical efficiency of running and it is suggested that, to obtain a good accuracy (better than 1%, P < 0.05) on mean value and variability of the mechanical parameters, measurements should be performed on at least 32-64 consecutive steps, which corresponds to about 15 to 20s of running.
Adult↗
High prevalence of activated protein C resistance in patients with systemic sclerosis.
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Blood Coagulation Tests↗