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Biomedical subjects

M Magistris

Publications and source records attributed to M Magistris.

12 recordsLinked to original sources
PubMed2005

[Sciatic lesions associated with hip surgery].

PURPOSE OF THE STUDY: The incidence of neurological lesions after hip surgery is underestimated because of variable clinical expression and functional disorders resulting from nerve injury and often considered to be the normal course after hip surgery. The incidence of nerve lesions after hip surgery for fractures of the proximal femur remains to be detailed. MATERIAL AND METHOD: This retrospective study included 20 cases of sciatic nerve injury following hip surgery (2554 THA, 394 revision THA, 4632 osteosyntheses or hemiarthroplasties of the proximal femur). We noted degree of recovery of the neurological deficit and deterioration of the patients' quality-of-life. The prognosis was determined on the basis of clinical and electromyographic data. RESULTS: The incidence of nerve injury after hip surgery was 0.5% after THA, 1% after revision THA, and 0.08% after osteosynthesis or hemiarthroplasty of the proximal femur. The etiological factor remained unknown in the majority of the cases. The prognosis was tightly related to the type of neurological lesion as defined by the electrophysiological study. Three revision procedures were performed: two for drainage of a compressive hematoma and one to release the sciatic nerve (neurolysis). The prognosis depended on the type of neurological lesion as established by the electroneuromyographic study. DISCUSSION: Severe axonotmesis is associated with late recovery, generally incomplete recovery, and poor long-term functional outcome.

Aged↗
PubMed2005

Radiation protection aspects of a 4 MW target.

The CERN Superconducting Proton Linac (SPL) is expected to provide a 2.2 GeV, 4 MW proton beam to feed facilities such as, for example, a neutrino factory or a neutrino superbeam. Material activation in such facilities is an important aspect that has to be taken into account at an early stage in designing it. In particular, the choice of the target has consequences on the induced radioactivity and dose rates in the target station and its surroundings. In the present work, the radiological aspects of a stationary target made up of tantalum pellets are compared with those of a free-surface jet of mercury. An estimation of the hadronic inelastic interactions and the production of residual nuclei in the target, the two concentric magnetic horns, the decay tunnel, the surrounding rock and a downstream dump were performed for both targets using the Monte Carlo code FLUKA. The aim was to assess the dose-equivalent rate that is to be expected during maintenance work and to evaluate the amount of residual radioactivity, which will have to be disposed of after the facility has ceased operation. The problem of after-heat in the tantalum target and the consequences of raising the proton beam energy from 2.2 to 4 GeV were also investigated.

Computer Simulation↗
PubMed2005

Radiation issues in a radioactive ion decay ring.

In a beta-beam facility, a pure beam of electron neutrinos, or their antiparticles, are produced by the decay of fully stripped radioactive ions (6He and 18Ne) circulating in a storage ring. Since the beam is not extracted from the ring, all the particles will eventually be lost somewhere in the machine and thus activate the accelerator components and the surrounding concrete and rock. In particular, as nuclei change their charge in beta-decay, a large part of the particles will be lost in the arcs of the decay ring and mainly irradiate the magnets. The density of inelastic interactions of hadrons in the magnets, concrete and rock and the track-length distribution of secondary hadrons were calculated by means of the FLUKA Monte Carlo code. These values were used to estimate the induced radioactivity in the facility, the dose rates expected in the decay ring and the consequences for the environment.

Beta Particles↗
PubMed2002

Thoracoscopic sympathectomy using ultrasonic coagulating shears: a technical improvement in the treatment of palmar hyperhidrosis.

Thoracoscopic sympathectomy has emerged in recent years as the treatment of choice for primary palmar hyperhidrosis when medical treatment fails. Postoperative complications have been reported in large series, however, including neurologic problems such as temporary or definitive Horner syndrome and peripheral nerve injuries. The authors report the use of ultrasonic coagulating scissors instead of electrocautery for the dissection and removal of a segment of sympathetic chain in an 11-year-old girl. A bilateral procedure was performed sequentially through three 5-mm axillary trocars on each side. The use of ultrasonic shears eliminates the risk of distal nerve injury induced by the spread of electric current and could possibly reduce the incidence of the above-mentioned complications.

Child↗
PubMed2002

[Anxiety and acceptance of gynecological laparoscopic operations].

BACKGROUND: To evaluate the acceptance of gynecological laparoscopic operations. METHODS: A comparative analysis has been performed in a group of 32 women by analyzing a) the cognitive component, by means of 2 questionnaires administered before and after the operation and b) the emotional component, by evaluating the pre- and post-operative anxiety levels (State anxiety) and the constitutional ones (Trait anxiety) using the STAI Y test. The anxiety level of our group has been compared with that attributed to the general population by means of the Z test. Moreover, significant correlations have been searched between: 1) pre- and postoperative Trait and State anxiety, through the Pearson's correlation test; 2) the variables investigated by the two informational questionnaires and the anxiety measures, through the Student t test; 3) the informative variables themselves through the c2 test. RESULTS: Postoperative State anxiety is lower than that of the general population (p<0.05); a significant correlation exists between post- operative State and Trait anxiety (p<0.05); Trait anxiety is higher when fantasies linked to the operation are characterized by fear (p<0.05), and attribution of the decision to operate to the doctor (p<0.05); post-operative State anxiety is higher when the level of education is low (p<0.05) and the attribution of the decision to operate is to the doctor (p<0.05); a significant correlation exists between fantasies characterized by fear and the experience of postoperative pains, between postoperative pains and attribution of the decision to operate to the doctor (p<0.05) and between fantasies characterized by fear and attribution of the decision to operate to the doctor (p<0.05). CONCLUSIONS: Higher anxiety levels have been detected in the pre-operative phase, in less educated patients and when the decision to operate has been attributed to the doctor. A not wholly convinced personal attitude has been accompanied by preoperative fantasies characterized by fear and has resulted in subjectively more painful postoperative course.

Adolescent↗
PubMed2001

Paraneoplastic anti-CV2 antibodies react with peripheral nerve and are associated with a mixed axonal and demyelinating peripheral neuropathy.

Subacute sensory neuronopathy with anti-Hu antibodies is the best-characterized paraneoplastic peripheral neuropathy associated with carcinoma. Anti-CV2 antibodies, another group of paraneoplastic antibodies, react with a 66-kd brain protein belonging to the family of Ulip/CRMP proteins. The manifestations associated with anti-CV2 antibodies include cerebellar degeneration, uveitis, and peripheral neuropathy. Some of these patients also have anti-Hu antibodies. We have compared the clinical, electrophysiological, and pathological characteristics of the peripheral neuropathy in 9 patients with anti-CV2 antibodies (3 of whom also had anti-Hu antibodies) and 12 patients with only anti-Hu antibodies. Data for patients with anti-Hu antibodies alone indicated subacute sensory neuronopathy. Patients with anti-CV2 antibodies had a mixed axonal and demyelinating sensory motor neuropathy that was sometimes superimposed on subacute sensory neuronopathy when both anti-CV2 and anti-Hu antibodies were present. Unlike anti-Hu antibodies, anti-CV2 antibodies reacted with peripheral nerve antigens, as shown by their ability to bind to a 66-kd protein in human and rat nerve on Western blot analysis and to immunolabel peripheral nerve axons and sensory neurons on immunohistochemical study.

Aged↗
PubMed2000

Exercise test in muscle channelopathies and other muscle disorders.

We studied the percentage change in compound muscle action potential (CMAP) amplitude and area during and after a 5-min maximal contraction of the muscle. The exercise test (ET) was performed on 64 patients with different muscle disorders and on 46 normal controls. The range of normal ET values was defined as the mean + 2 SD of the control values. The mean sensitivity of the test was 63% in the whole group with ion channel muscle disorders, the highest sensitivity being seen in primary periodic paralysis (81%) and the lowest in chloride channelopathies (17%). In thyrotoxic periodic paralysis, the ET was abnormal in the three of the four patients studied. In patients with myotonic dystrophy, a smaller than normal increase in CMAP amplitude occurred during and after exercise, whereas in proximal myotonic myopathy a normal initial increase in CMAP amplitude was followed by an abnormal decrement. We conclude that the ET can be of use in confirming abnormal muscle membrane excitability in patients with calcium and sodium channelopathies and thyrotoxic periodic paralysis. In chloride channelopathy, the test may also be abnormal, but shows no, or only a small, increase in amplitude or area in the immediate postexercise period. The test may also be abnormal in proximal myotonic myopathy, but is normal in myotonic dystrophy.

Action Potentials↗
PubMed1998

Terminating attacks of ocular neuromyotonia.

We examined a 30-year-old woman who, for 6 months, had suffered from ocular neuromyotonia, which consisted of episodic ocular depression. Apart from the ocular complaint, her medical history and the clinical findings were unremarkable. The patient discovered that she could terminate each episode of tonic ocular depression instantly by forcefully directing her gaze upward. Stretching the affected muscle might also prove to be an effective way of ending attacks of neuromyotonia in other patients suffering from this condition.

Adult↗
PubMed1991

Impact of environmental and genetic factors on codeine analgesia.

The polymorphic cytochrome P-450 DB1 (P-450 IID6) is responsible for the O-demethylation of codeine to morphine by human liver microsomes. The influence of P-450 DB1 variable activity on the bioactivation of codeine in vivo to morphine and on its analgesic effect was investigated in phenotyped healthy volunteers--7 extensive [EM] and 1 poor [PM] metabolizer of debrisoquine. After pretreatment with oral placebo or quinidine sulphate 50 mg, codeine phosphate 100 mg or placebo were administered orally according to a double-blind randomized crossover design. In EM subjects the plasma morphine Cmax was 17.9 nmol/l, whereas virtually no morphine was detectable after quinidine pretreatment (1.5 nmol/l), and in the PM subject (0.60 nmol/l). In EM codeine significantly increased subjective (VAS) and objective (R-III reflex) pain thresholds in response to selective transcutaneous nerve stimulation, whereas no significant analgesia was detected after placebo, or after codeine with quinidine pretreatment, or in the PM. In PM of genetic origin, or due to environmental alteration of the phenotypic expression (i.e. drug interaction), codeine is not activated into morphine and is an inefficient analgesic.

Administration, Oral↗
PubMed1984

[Hereditary fragility of the peripheral nerves. Clinical and neurophysiologic study of 23 cases. Review of the literature].

The literature concerning hereditary neuropathy with liability to pressure palsies is reviewed. We describe 23 affected members of 7 families; one of them studied since 1966. The differential diagnosis with heredofamilial plexus brachialis neuropathy and Charcot-Marie-Tooth syndrome is discussed. Our subjects are similar to those described in the literature; they have presented episodes of recurring painless palsies, most often related to minimal neural trauma. Neuromyographic examinations revealed chronic denervation, slowed conduction velocities particularly at entrapment sites and sometimes neurapraxia. We emphasise the conduction blocks for we believe their tendency to long duration (up to 8 years) and presence at several sites in a same patient are characteristic of this affection. Moreover we suggest that this neurapraxia is related to the existence of the tomacula. The possibilities of prevention and treatment are reviewed (two neurolyses performed in one patient presenting with long lasting conduction blocks at 2 entrapment sites have proved to be a successful treatment.

Adolescent↗