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Biomedical subjects

F Benvenuti

Publications and source records attributed to F Benvenuti.

At least 37 records · Page 2Linked to original sources
PubMed1997

Flexibility of anticipatory postural adjustments revealed by self-paced and reaction-time arm movements.

In standing humans, it is not certain whether anticipatory postural adjustments associated with rapid, voluntary elbow flexion movements (focal movements) originate as a selection from preset synergies or as the result of specific planning of motor commands. We studied these muscle recruitment patterns when the same focal movement was made under behavioral conditions of a self-paced task (SPT) and a reaction-time task (RTT). While standing still, eight normal subjects performed focal movements under the SPT and RTT behavioral conditions and under three different biomechanical conditions: (1) unloaded-upright, (2) loaded-upright (holding a 3800-g metal bar), and (3) unloaded-forward leaning. Anticipatory postural adjustments were quantified using the latency and duration of electromyographic (EMG) data and the center of pressure (COP) displacement data. Postural-kinematic [joint and body center of gravity (COG) motion] data were used to quantify the anticipatory postural program's effectiveness at preventing postural movement. Focal movement kinematics and associated EMG activity differed due to biomechanical but not behavioral (SPT vs. RTT) conditions. The maximum and net displacement of the body COG measurements did not differ between the behavioral conditions. The amplitude, timing, and net movements of lower extremity joints were influenced by the behavioral conditions. However, the behavioral conditions significantly affected the phasing (including order of activation) and duration of anticipatory postural EMG activity and the phasing of COP displacements under certain biomechanical conditions. These findings support the theory that anticipatory postural adjustments are planned in detail.

Adolescent↗
PubMed1997

Covalent bonding of heparin to a vinyl copolymer for biomedical applications.

In order to prepare polymer surfaces of vinyl type, provided with long-term haemocompatibility, a commercial ethylene-vinyl alcohol copolymer (EVAL) was covalently heparinized, employing two different bifunctional reagents (adipoil chloride and hexamethylene diisocyanate). The amount and activity of the heparin bonded to the polymer films were evaluated as a function of the concentration of the heparin solutions employed. Also, the influence exerted by the presence of various hydrophilic 'spacing arms' of different molecular weights, either neutral or provided with electrical charge, was investigated. By in vitro measurements of activated partial thromboplastin time it was seen that all the heparinized samples possessed a high degree of haemocompatibility. For the sake of comparison, heparin was also bonded ionically to EVAL functionalized by introduction of quaternary ammonium groups bonded covalently (by adipoil chloride) to the hydroxyl groups of the polymer. It was seen that the covalent immobilization system provides the polymer surfaces with a superior haemocompatibility.

Biocompatible Materials↗
PubMed1997

[Bilateral adrenal lymphoma. A case report].

A rare case of malignant non-Hodgkin lymphoma of the adrenal gland in a 59-year-old male is reported. This patient, completely healthy, observed for a routine check after a laparoscopic cholecystectomy performed one year before, underwent an explorative laparatomy for getting information about a retroperitoneal mass, ultrasound scan observed. A CT guided needle biopsy was inconclusive to clarify this rare haematological diagnosis.

Adrenal Gland Neoplasms↗
PubMed1995

Foot pain and disability in older persons: an epidemiologic survey.

OBJECTIVE: To investigate the prevalence of foot pain in older people and its association with pathological conditions of the feet and with disability in basic and instrumental activities of daily living. DESIGN: Cross-sectional survey of a community-dwelling older population. PARTICIPANTS: A total of 459 subjects, 73% of the population aged 65 years and older living in Dicomano, Florence, Italy. MEASUREMENTS: A standardized medical examination was performed by a geriatrician to collect information on the presence of pain, specific problems of the feet, gait, and several indicators of physical health status. Disability in basic and instrumental activities of daily living was evaluated by self-report. RESULTS: The prevalence of foot pain was very high, especially in subjects affected by calluses or corns, hallux deformities, hammer toes, pes planus, and edema and among those who complained of difficulty in looking after the basic needs of the feet. Patients with foot pain needed a greater number of steps and longer time to walk the same distance. Foot pain was associated with a higher prevalence of disability in instrumental activities of daily living, particularly those related to standing and ambulation capacities, but it was not related to higher prevalence of disability in basic activities of daily living. CONCLUSIONS: Foot pain is associated with specific conditions of the feet and disability in instrumental activities of daily living. Adequate assessment and treatment of foot problems may prevent foot pain and potentially reduce risk of disability. This hypothesis needs to be tested in longitudinal studies and specific intervention trials.

Activities of Daily Living↗
PubMed1993

Male sexual impotence in diabetes mellitus: vasculogenic versus neurogenic factors.

In an attempt to understand better the role of vascular and neurogenic alterations in the pathophysiology of diabetic impotence, 29 impotent male patients with diabetes mellitus (DM) were investigated by means of doppler ultrasound examination (DUE) of penile arteries, sacral evoked responses (SERs), peripheral nerve conduction studies, and, in most cases, nocturnal penile tumescence monitoring (NPTM). Fourteen patients showed isolated alterations of penile vascular supply, four isolated alterations of penile segmental innervation, and seven combined vasculogenic and neurogenic abnormalities; finally, in four patients, DUE, SERs, and NPTM were normal. One patient, in spite of the presence of marked vasculogenic and neurogenic alterations, showed nocturnal penile erections. Results confirm that vascular obstruction, more than nerve damage, plays a primary role in the pathophysiology of diabetic erectile failure, and stress the importance of psychogenic factors. The observation that some patients presented marked involvements of both arterial supply and neurological pathways only a few years, or even 1 year, after the diagnosis of the disease, indicates the need of an early screening of the vascular and neurological status, even in asymptomatic patients. Furthermore, all patients with altered SERs had peripheral neuropathy; on the other hand, six patients with peripheral neuropathy had normal SERs. This result stresses the diagnostic importance of the electrophysiologic studies of sacral segmental innervation and indicates further that in a comprehensive diagnostic protocol of diabetic impotence the study of SERs should be performed only in patients with peripheral neuropathy.

Adult↗
PubMed1992

Subjective and metabolic effects of clodronate in patients with advanced breast cancer and symptomatic bone metastases.

Twenty postmenopausal women (aged between 46 and 67 years old) with skeletal metastases from breast carcinoma were treated with clodronate 450 mg i.v. daily for 5 days and thereafter with 100 mg i.m. daily for 10 days. All patients received standard hormonal therapy (tamoxifen). Symptomatic pain (evaluated according to a linear analog scale), performance status (according to Karnofsky), serum alkaline phosphatase, serum creatinine and osteocalcin were measured before and after treatment on days 5, 15, 30 and 45. Scanning by radiology were performed pre- and post-therapy. Bone pain was significantly reduced in 15 out of 20 patients. After clodronate treatment the base line value of circulating osteocalcin (3.2 +/- 1.6 ng/ml) showed a significant increase on days 30 and 45 (p less than 0.001). Radiological assessment of bone lesions showed stable disease in 18 patients and progression in two patients. No adverse side effects were observed. These data show that clodronate provided pain relief in 75% of treated patients and the increase in circulating osteocalcin levels can be considered a marker of the stabilization of skeletal metastatic lesions.

Aged↗
PubMed1988

Flunarizine-induced parkinsonism in the elderly.

Twenty-seven patients (19 women and 8 men, ages 63 to 88 years; mean, 74 years) displayed mild to moderate parkinsonism and altered ballistic motor performances during long-term flunarizine treatment. One month after, flunarizine withdrawal, 20 patients showed clear-cut improvements in both clinical features and ballistic motor performances; a complete recovery within 6 months was observed in all these patients but one, who still showed very mild slowness of movement. On the other hand, seven patients showed little clinical improvement and still maintained markedly altered ballistic motor performances 1 month after drug withdrawal. At the 2-month follow-up assessments, either they did not improve further or they deteriorated; they were successfully treated with L-dopa and, despite the ameliorations, after 12 to 24 months they still have definite parkinsonian syndrome. The authors conclude that (1) flunarizine, even at the recommended dose (10 mg daily), can induce reversible parkinsonism, at least in subjects older than 60; (2) the persistence of a marked symptomatology 2 months after flunarizine withdrawal should lead to starting treatment with antiparkinsonism drugs; (3) the study of ballistic movements is proposed as a useful tool for objective quantification and early detection of bradykinesia.

Aged↗
PubMed1988

Effects of expected perturbations on the velocity control of fast arm abduction movements.

A triphasic electromyographic pattern of sequential activation of agonist, antagonist, and again agonist muscles underlies rapid or ballistic limb movements in humans. The first agonist burst reflects muscular force accelerating the limb, the antagonist burst is mainly related to the braking process of movement, while the second agonist burst is considered a reactive adjustment to the deceleration. The duration of the first agonist burst has been reported to be constant for movements of different amplitudes, thus suggesting that only changes in its amplitude contribute to the velocity control of movement. The present research has been undertaken to investigate the strategy whereby the nervous system increases agonist impulsive force for ballistic performance in response to experimental conditions requiring perceptual and/or provisional processes related to expected changes in load or accuracy constraints. The effects of expected perturbations of different strengths on some kinematic and electromyographic variables of fast arm abduction movements performed in a step-tracking task and in an outer-stop terminated task were analyzed in normal subjects. All motor performances were characterized by triphasic electromyographic patterns. In the absence of expected perturbations, the mean velocity of the movements was markedly higher in the outer-stop terminated task. Correspondingly, greater amplitudes and durations of the first agonist burst were observed. In both types of motor tasks, when expected perturbations were inserted, the velocity of the movement increased as well as the amplitude and the duration of the first agonist burst. These results, in agreement with previous observations, indicate that the normal mechanism, whereby the nervous system increases agonist impulsive force in rapid movements, comprises changes not only in the amplitude but also in the duration of the first agonist burst.

Adult↗
PubMed1987

Reeducative treatment of female genuine stress incontinence.

Three-months re-education treatment of genuine stress incontinence was given to 26 female outpatients: 22 patients completed the treatment programme and 4 interrupted it for various reasons. The aims of the treatment were both to correct compensatory habits that patients used to conceal or reduce leakage accidents and to give specific education and strengthening of pelvic floor muscles. All patients who completed the three-months treatment definitely improved and 7 were cured. Accordingly a marked reduction or absence of weekly incontinence episodes as well as a reduction of the daily frequency of micturition was observed. On vaginal palpation a clear-cut improvement of pubococcygeous muscle contractility was detectable. Urethral closure pressure profilometry showed significant improvement of functional urethral profile length at rest and of maximal urethral closure present both at rest and during maximal voluntary contraction of the pelvic floor muscles. Micturition cystourethrography, repeated in 15 patients at the end of the treatment, showed a clear-cut improvement of bladder neck suspension defects in all but 2 patients. Follow-up assessments showed that the clinical effects were long-lasting. Possible mechanisms of this re-educative technique are discussed.

Adult↗
PubMed1985

Auditory and somatosensory evoked potentials (AEPs and SEPs) and ballistic movements in Parkinson disease.

In five patients with initial idiopathic Parkinson disease AEPs (early and late components of auditory evoked potentials), SEPs (somatosensory evoked potentials) and arm ballistic movements (abduction of the humerus) were studied. Experimental sessions were conducted before starting treatment (L-Dopa plus Carbidopa) and at two and six month intervals. Before treatment evoked potential abnormalities were found in four out of five patients; EMG patterns underlying ballistic arm abduction movements were altered in all patients; corresponding prolonged duration of initial movements and low mean velocities were found. After treatment AEP and SEP showed a reduction of previously observed abnormalities and both EMG patterns and kinematic variables consistently improved. It is suggested that the electrophysiological investigations employed in this preliminary study may be a useful tool in clinical and pharmacological researches on Parkinson disease.

Aged↗
PubMed1984

Human ballistic arm abduction movements: effects of L-dopa treatment in Parkinson's disease.

In patients with Parkinson's disease who had never previously been treated with any antiparkinsonism drug, we studied the effects of L-dopa on ballistic arm abduction movement in a step-tracking task. L-Dopa treatment increased the mean velocity of the initial movement towards the target without loss of accuracy and with improved motor performance under open-loop conditions. Performance also improved in motor tasks with expected perturbation. EMG patterns of arm abduction movements showed abnormal features in untreated patients and improved after L-dopa treatment.

Adult↗
PubMed1978

[Risk hypothesis in the use of "non-carbon copy paper"].

Some kinds of "carbon less copy-paper" presently used in Italy were examined. The analysis showed the presence on the paper of mycrocapsules containing special inks formed by organic dyes dissolved in mineral oil and, sometimes, polychlorobyfenils. Therefore there is a possible risk for the workers using carbon less copy-paper. It is necessary therefore to complete the research in order to demonstrate this hypothesis also from biological point of view.

Coloring Agents↗
PubMed1977

[Aromatic polycyclic hydrocarbons in plants using bituminous materials].

In recent years bituminous materials have been frequently used in several industrial works for waterproofing, protection and insulation of many amterials such as paper, (asphalted) cardboard, wood, etc. Constant components of these materials are the polyciclic aromatic hydrocarbons (PAH), of which we know the biological activity and, for some of them, the cancerogenic effects. The aim of this work is to evaluated the possible risk from exposure to polycicilic aromatic hydrocarbons for workers in operations with bituminous materials. By an analytical method for the determination of PAH, we have examined the polycicilic aromatic hydrocarbons in asphalt, air-blown asphalt, tars and, then, in fumes from hot treatments of those materials. After analysing the fumes developed under controlled conditions, in laboratory, and those taken from work-environment, we have reported the results of our search.

Air Pollutants↗