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Biomedical subjects

M Martini

Publications and source records attributed to M Martini.

At least 127 records · Page 7Linked to original sources
PubMed1990

[Treatment of bone infection by plaster of Paris pellets impregnated with antibiotics].

In two prospective clinical trials, the authors treated 83 chronic osteomyelitis from various origins by sequestrectomy completed with insertion of Plaster of Paris pellets impregnated with antibiotics. After a review of the experimental and clinical reports on the subjects, the authors give their results: 61.5% of healings and 38.5% of failures. Because of the small number of cases, it was not possible to find out an explanation for this fair results. However wide extension of the lesions, which is frequent in chronic haematogenous osteomyelitis, seems to be a contraindication to the technics. The authors conclude to the necessity of carrying up new experiments with new antibiotics and large series of patients in order to point out the righted indications of the method.

Adolescent↗
PubMed1989

[Results of the surgical treatment of chronic hematogenous osteomyelitis of the humerus. A series of 46 cases].

Forty-six patients with chronic haematogenous osteomyelitis of the humerus were treated surgically between 1968 and 1987. Operation involved decompression, sequestrectomy and saucerisation, and was always covered by between 10 and 60 days of antibiotic treatment. Forty-three patients were followed up for between 3 months and 20 years, 36 for more than 1 year. Thirty-nine patients achieved healing after one operation and 7 relapsed, of whom 6 healed after a second procedure.

Adolescent↗
PubMed1989

Non-contacting electrode system for the measurement of strain generated potentials in bone.

Current methods employing contact electrodes for the measurement of the electromechanical properties of bone produce errors in the measurement due to the effects of polarization at the bone-electrode interface, and the flow of electric charges in the bone measuring circuit. In addition, signal artefacts may result from the movement of an electrode in contact with a specimen undergoing mechanical deformation. The principles for a non-contacting method, based on charge induction on a conductive plate placed in the field of a charged body (bone), and the resulting non-contacting electrode system are presented in this paper. The new electrode enabled measurement of strain generated potentials (SGP) in bone with minimal effect from the measuring circuit and provided new results previously masked by contacting measurement methods. Furthermore, the new electrode is a potential tool for further investigation of the in vitro electromechanical behaviour of bone, particularly in partially hydrated specimens and in vivo, thereby avoiding invasive methods or use of ionizing radiation.

Action Potentials↗
PubMed1989

Static and dynamic properties of synaptic transmission at the cyto-neural junction of frog labyrinth posterior canal.

The properties of synaptic transmission have been studied at the cyto-neural junction of the frog labyrinth posterior canal by examining excitatory postsynaptic potential (EPSP) activity recorded intraaxonally from the afferent nerve after abolishing spike firing by tetrodotoxin. The waveform, amplitude, and rate of occurrence of the EPSPs have been evaluated by means of a procedure of fluctuation analysis devised to continuously monitor these parameters, at rest as well as during stimulation of the semicircular canal by sinusoidal rotation at 0.1 Hz, with peak accelerations ranging from 8 to 87 deg.s-2. Responses to excitatory and inhibitory accelerations were quantified in terms of maximum and minimum EPSP rates, respectively, as well as total numbers of EPSPs occurring during the excitatory and inhibitory half cycles. Excitatory responses were systematically larger than inhibitory ones (asymmetry). Excitatory responses were linearly related either to peak acceleration or to its logarithm, and the same occurred for inhibitory responses. In all units examined, the asymmetry of the response yielded nonlinear two-sided input-output intensity functions. Silencing of EPSPs during inhibition (rectification) was never observed. Comparison of activity during the first cycle of rotation with the average response over several cycles indicated that variable degrees of adaptation (up to 48%) characterize the excitatory response, whereas no consistent adaptation was observed in the inhibitory response. All fibers appeared to give responses nearly in phase with angular velocity, at 0.1 Hz, although the peak rates generally anticipated by a few degrees the peak angular velocity. From the data presented it appears that asymmetry, adaptation, and at least part of the phase lead in afferent nerve response are of presynaptic origin, whereas rectification and possible further phase lead arise at the encoder. To confirm these conclusions a simultaneous though limited study of spike firing and EPSP activity has been attempted in a few fibers.

Action Potentials↗
PubMed1989

[High extracellular concentrations of potassium and rubidium modulate the synaptic transmission in the frog labyrinth].

High extracellular K or Rb levels (20 mM) produce an increase in the resting EPSP and spike frequencies recorded intra cellularly from single fibres of the posterior nerve in the isolated frog labyrinth. The afferent discharge facilitation proved to be inversely related to the fibre's initial resting activity. The K effect is systematically larger than the Rb effect. High sensitive and scarcely sensitive units may be identified with respect to K and Rb action. The present findings suggest that, according to previous models of hair cell functioning, the K and Rb effects are mediated by a raise in intracellular Ca concentration which sustains an increased transmitter release at the cyto-neural junction.

Action Potentials↗
PubMed1989

[Yersiniosis].

Explore the source record for details and available documents.

Adolescent↗
PubMed1988

High perilymphatic potassium and rubidium levels modulate the sensory resting discharge in the isolated frog labyrinth.

The effects of high perilymphatic K+ and Rb+ concentrations (20 mM) on the posterior canal resting discharge have been examined in the isolated frog labyrinth. Both K+ and Rb+ produced an increase in spike frequency which is sustained by a parallel increase in the excitatory postsynaptic potential (EPSP) emission rate. High K+ and Rb+ levels reduce the size of the afferent spike, broaden its time course but do not induce repetitive activity at the axon level. The K+ and Rb+ facilitation proved to be inversely related to the fibre's initial resting activity. The facilitation produced by increased K+ was usually larger than that in Rb+ solution. High sensitive and low sensitive units with similar low resting discharge were detected in relation to their response either to K+ or Rb+. The effects of both ions can be explained on the basis of their interactions with the presynaptic hair cell currents.

Action Potentials↗
PubMed1988

The effect of barium and some channel blockers on sensory discharge of the frog labyrinth posterior canal recorded at rest and during rotation.

The effect on the afferent synaptic transmission of Ba2+, Sr2+, tetraethylammonium (TEA) and 4-aminopyridine (4-AP) has been investigated in the isolated frog labyrinth by intracellularly recording the posterior canal resting and evoked receptor discharge. BaCl2 (0.3 mM) or SrCl2 (1.8 mM) substitution for normal external CaCl2 restored the afferent activity without affecting the membrane potential of the sensory fibres. On further increasing Ba2+ concentration (0.5-5 mM) a dose-dependent increase in the EPSP and spike discharges was observed in all the units examined. Ba2+ (1.8-4 mM) removed the depression of the sensory activity operated by CoCl2 (3 mM), while its facilitatory effect was completely antagonized by raising Ca2+ concentration (up to 10 mM). TEA (20 mM) elicited a clear-cut increase in the EPSP and spike discharges which, however, was less consistent than that produced by Ba2+ (1 mM). The increment in spike frequency produced by TEA and Ba2+ proved to be inversely related to the initial resting firing level of the different units. The 4-AP (4-20 mM) effect resulted in a decrease of the sensory activity, which was fully restored by TEA or Ba2+. In normal saline a linear relationship was found between the mean unit resting discharge and the respective excitatory peak response during sinusoidal rotation (0.1-0.3 Hz). This result suggest that the mechanical response is mainly determined by the unit resting level. Consistent evoked responses were obtained under TEA and Ba2+ treatment which proved to depend linearly on the new mean resting discharge of the different units. Conversely, a reduced evoked response was invariably observed in all the fibres tested in the presence of 4-AP. The present results suggest that Ba2+ and Sr2+ may substitute for Ca2+ in the transmitter release process at the cyto-neural junction, the ability of Ba2+ being even larger than that of Sr2+ and Ca2+ itself. The effects of TEA and 4-AP are discussed in the light of their possible interaction with the presynaptic K+-currents recently described in hair cells.

4-Aminopyridine↗
PubMed1988

Model to characterize strain generated potentials in bone.

A model has been developed to characterize the strain generated potentials (SGPs) in bone. The model relates the SGP signal to the rotation (reorientation) of the spontaneous dipoles of bone in response to mechanical deformation. The effects of bone structural conditions and the measuring circuitry on the recorded potential are both accounted for by the model.

Animals↗
PubMed1988

Bone and joint tuberculosis: a review of 652 cases.

The results of a computerized study of 652 cases of bone and joint tuberculosis were presented. The cases were studied according to a program of 76 variables. From the various results of such a study, the following data were found. A high rate of tuberculous osteomyelitis (19%) and of tuberculosis of the upper limb joints (14%) were found. The reliability of a new x-ray classification based on the degree of destruction of the joint should be emphasized along with the reliability of biological examinations. All patients were treated according to the same principles; chemotherapy against tuberculosis, and surgical measures against musculoskeletal destruction. The results were excellent for tuberculosis. A favorable response to chemotherapy was found in 98% with only 3% of the cases relapsing. Anatomical results were surprisingly good and excellent in 56% of the cases, in spite of the low rate of surgery performed. Fair anatomical results often gave good functional results if no deformity persisted.

Adolescent↗
PubMed1988

[Results of the conservative treatment of 171 cases of Pott's disease without neurologic involvement].

One hundred and seventy-one patients suffering from Pott's disease of the spine were treated by the same surgeons between 1965 and 1985. Chemotherapy, which varied during the period, was given in every case. Plaster immobilization was only used in the first 41 patients, until the authors concluded that it did not prevent worsening of the kyphosis. For technical reasons, surgical treatment was not used in any of these 171 patients. The results showed, in children, not only the usual development of kyphosis in the course of treatment but worsening later in the course of growth. For this reason, arthrodesis by the anterior route should be considered to obtain early fusion when the facilities and technical skills are available. In adults, the indications for surgery are more limited. Whilst there is a risk that kyphosis may reach a mean of 20 degrees during conservative treatment, it does not increase later. The authors conclude that it is necessary to link the indications for surgery to the availability of facilities at each individual hospital called upon to treat these patients.

Adolescent↗
PubMed1987

[Tuberculous osteoarthritis of the hip in adults].

We have carried out a retrospective study of 49 cases of tuberculosis of the hip in adults, all treated by one of the authors. All patients presented with destructive lesions in the hip. Abscess formation and sinuses were infrequent. A scientific diagnosis was obtained in 46 cases. All the patients were treated with chemotherapy for 6 to 12 months. The hip was immobilised for 3 months, either by skeletal traction followed by a plaster cast, or by a cast alone, depending on the need for correction of deformity. If deformity was fixed or absent, immobilisation was not undertaken. A favourable response to chemotherapy was observed in all 40 patients who were available for follow up. One relapsed after 12 months. Some hips progressed to total bony fusion, with the remainder showing either complete or moderate stiffness. The functional result depended on the presence of pain and the degree of deformity, and the need for surgery was determined by these two factors. Corrective osteotomy or arthrodesis have been performed. The indications for operation are discussed considering the sex, occupation and needs of the patient. The place of excision arthroplasty and of total replacement is examined.

Adolescent↗