GROUND REACTION FORCE PATTERNS FOR THE EVALUATION OR MOTOR RECOVERY IN ATHLETES AFFECTED BY KNEE INJURIES

INTRODUCTION Vertical jump is an exercise widely adopted to evaluate some motor characteristics of the athletes. Vertical component of the ground reaction force (VGRF) is often used to gain more information regarding efficiency and motor coordination of the lower limbs. The aim of this study is to evaluate vertical jump performances of subjects afflicted by ACL injury, by means of VGRF patterns. METHODS Ten healthy rugby players (HP) were the sample of this study, together with four subjects who present a ACL pathology (PP), due to a previous injury. At the time of the acquisition all the pathological subjects had been reintegrated in the team training and competitive programs. The subjects were asked to perform 20 two-legged vertical jumps, as high as possible, keeping one foot at a time over a Kistler force platform. Arms were behind their back, in order to minimize the contribution of the upper part of the body to the thrust of the legs. Ground reaction forces were recorded by means of a force platform at the sampling rate of 1000 Hz, and data were normalized in amplitude to the body mass. Jumping height was computed through the flight time. RESULTS In agreement with previous studies, a common pattern in the GRF for HP subjects was observed; the typical VGRF time course was characterized by an initial decrease of the force until a minimum, followed by two maxima with a further relative minimum in between, the first peak is the absolute maximum. Amplitude and timing of these parameters were examined for the analysis. The mean jump height evidenced statistical diierences only between one PP subject and the mean jump height of the HP group. By considering VGRF amplitude, significative differences have been found only between the amplitude of the first minimum (healthy = 0.25 BW, pathological = 0.36 BW) while no differences were found between the absolute maxima. By considering the timing of the different phases it has been observed that PP group show a longer delay between the initial minimum and the first maximum. As far as the VGRF time course is concerned, we noted for PP subjects individual behaviors in comparison with the average pattern of the HP. Furthermore, the presence of a strong asymmetry between the curves of the healthy and pathological limb, were observed. CONCLUSIONS Jumping height does not seem to be a parameter useful in designating motor impairments in subjects with ACL injuries. However, as far as the VGRF is concerned, intra and inter individual significative differences may be observed. A common characteristics of PP group is the reduced capacity to perform the eccentric phase. While the amplitude of the maxima is similar, VGRF patterns of the PP group show individual characteristics and appreciable asymmetries between the two legs. These results allow to speculate about compensatory motor actions and confm that the majority of the PP subjects were from a complete motor recovery

GENDER DIFFERENCES IN JOINT MOMENTAND POWER MEASUREMENTS DURING VERTICAL JUMP EXERCISES

INTRODUCTION Gender differences are apparent not only in the absolute maximum force level but also in the rates at which the force and/or power is produced(Koml et al., 1978). The predominant requirement for success in a large number of athletic skills IS explosive power. For the lower body, this IS perhaps best exemplified by vertical jump. Vertical jumps a complex ballistic multi-joint movement, where the musculature around the hip, knee and ankle joints collectively operate to produce patterned movements. The purpose of this study was to assess the effect of gender on the mechanical output of the lower limb joints (moments and powers), during vertical jumping exercise. Methods: Eight male (age 22.4 yrs) and eight female ( age 21.7yrs) athletes served as subjects. After 20 min. of standard warm-up, the subjects performed 20 maximal vertical jumps with the arms behind the back. The 3-D coordinates of ten anatomical landmarks ( five per leg) were detected by the opt electronic ELITE system (Ferringno & Pedotti, 1985) with a sampling frequency of 100 HzS simultaneously, the GRF signals were measured and acquired with a sampling frequency of 500 Hz. Internal joint centres and the corresponding moments and powers were estimated from anthropometric and kinematic data using a special software package Group differences were assessed by the Wilcoxon signed rank test Statistical significance was assessed at

LOWER LIMB KINETIC VARIABILITY IN VERTICAL JUMPING

For more that 50 years vertical jumping exercises have been widely used in sport practice as a measure of power not only to predict athletic ability but also to obtain indications on same near-muscular and motor characteristics of the athletes. The most interesting work in this area has been done by a research group at the Free University of Amsterdam. The studies of these authors evidenced very elegantly that kinetic analysis provides potentially more diagnostic information force derived indices. However, what the majority of previous studies on human extremely large intra subject variability of the joint kinetic variables. So far, no attempts have been made to gain more insight into the variability inherent in moment and power selected measurements in vertical jumping exercises. To the best of our knowledge, in fact, all the studies employed on or more homogeneous subject groups and presented data describing the average performance groups. Furthermore, frequently, when mean values of kinetic parameters for a group were calculated, only the highest jump of each subject was selected for the calculation. The present experiments were devised to gain more insight into the variability of aforementioned biomechanical parameters in order to determine the appropriate number of trails necessary to obtain a stable mean for these parameters and to investigate the interday variability. Eight recreational athletes were the subjects of this study. In two different test sessions, each subject performed 25 double-legged countermovement vertical jumps without the arm swing. Kinematic data, concerning the spatial position often anatomical landmarks (five per each leg), were recorded by means of an optoelectronic system (ELITE) with a sampling rate of 100 Hz. Simultaneously, ground reaction forces were measured with a Kistler force platform at the sampling rate of 1000 Hz. The internal joint centres, such as the corresponding moments and powers, were estimated by using a special software (SAFLO) which inputs were anthropometric, kinematic and kinetic data. Preliminary results show that, considering all the subjects, power mean value stability ranges from 11 to 16 trials. Interday correlation was higher for hip and ankle and lower for knee values. These results suggest the need to adopt multiple trial protocols to reach reliable results suitable for identifying meaningful performance differences

Production of epidermal growth factor in human hypertrophic prostate cells cultured in vitro

The Epidermal Growth Factor (EGF) plays an important role in the regulation of in vitro growth of prostate cells inducing a strong mitogenic effect. Nevertheless in our previous study we observed that the treatment of human hypertrophic prostate cell line U285 with exogenous EGF produces a restricted effect on the cellular growth rate. This phenomenon could be due to the capacity of the cells to produce EGF. In this study we aimed to verify this hypothesis by evaluating the presence of mRNA of EGF and EGF receptor (EGF-R) and of their translation products in U285 cells, before and after the treatment with suramin and exogenous EGF. Moreover we studied the effects exerted by these substances on the proliferative rate of the cells U285 after different treatment protocols. The presence in the cells of mRNA for EGF and EGF-R and of their translation products was demonstrated by means of reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods respectively. The modification of growth rate induced by these drugs was studied by FRAME Cytotoxicity Test. The operative modalities adopted to carry out these growth assays tended to 1) focus the effects of suramin in relation to in vitro cellular growth phase; 2) verify the reversibility of its effects; 3) ascertain if it was possible to antagonize the action of suramin by adding exogenous EGF. The results obtained from the RT-PCR showed the presence, in the control cells and in the treated ones, of mRNA coding for EGF and EGF-R. The immunocytochemical analysis indicated that 20% of the control cells are EGF positive, and 83% are EGF-R positive, confirming the results obtained with RT-PCR. Moreover, these stainings showed that the treatment with EGF does not significantly modify the percentage of cells marked by the anti-EGF antibody, while treatments with suramin and suramin plus EGF double this percentage. None of the treatments modifies the percentage of EGFR positive cells. The growth assays showed that the exposition to highest doses of suramin in the first 24 h of cultures causes a decrease (p<0.05) of the cellular proliferation during the following 48 h and 72 h and that these effects are irreversible. Moreover, a contemporaneous exposition of the cells to EGF and suramin at seeding strengthens the cytotoxic action of the last drug. To sum up, the demonstration of the presence in the U285 cells of mRNA coding for EGF and EGF-R and of the corresponding proteins, confirms the hypothesis that these cells can produce EGF. Moreover, the cytotoxicity experiments allowed a focusing of the role of the endogenous EGF in the regulation of the U285 cells proliferation and confirmed the importance of biological events that take place in U285 cells during the first 24 h of culture

Posttraumatic intraventricular haemorrhages

Of a series of 350 patients studied for blunt head trauma by CT scan 10 were found to have an intraventricular haemorrhage (IVH); in 8 cases we could find concomitant CT abnormalities as well as intracerebral contusion or haemorrhage, and in two cases no other CT abnormality was noted. CT scan represents the first reliable and non-surgical tool for identifying this process. Two possible mechanisms that govern the formation of an IVH are postulated: a) an erosion of the ventricular wall by an intracerebral haemorrhage; b) the rupture of subependymal veins deformed by the negative pressure following dilatation of the ventricular wall. The prognosis in our cases is severe

NATURAL OCCURRENCE OF GANGLIOSIDE LACTONES - ISOLATION AND CHARACTERIZATION OF GD1B INNER ESTER FROM ADULT HUMAN-BRAIN

A new ganglioside containing an inner ester linkage was extracted from adult brain specimens, obtained at the time of surgery on 51-70-year-old subjects, purified, and analyzed. It contains glucose, galactose, N-acetylgalactosamine, an N-acetylneuraminic acid in the molar ratio 1:2:1:2, but, on ion-exchange chromatography, behaves as a monosialoganglioside. Structural analyses showed its basic neutral glycosphingolipid core to be ganglio-N-tetraose ceramide, carrying a disialosyl residue on the 3-position of internal galactose. Sialidase degradation and chemical analysis of the products obtained after alkaline treatments suggested one sialic acid residue to be involved in an ester linkage. Fast atom bombardment-mass spectrometry indicated the presence of an inner ester linkage between the carboxyl group of the external sialic acid residue and a hydroxyl group of the internal one. On these bases, the new ganglioside can be assumed to be a GD1b in lactonic form. This ganglioside is present only in trace amounts in the brain of infants, but its content increases with age, reaching a value of 3.5% of total sialic acid in 51-70-year-old subjects