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Biomedical subjects

R Olmi

Publications and source records attributed to R Olmi.

At least 19 recordsLinked to original sources
PubMed1988

Analysis of electric and magnetic fields leaking from induction heaters.

Results are presented of an investigation on electric and magnetic fields leaking from inductive (magnetic) heaters that are used for thermal processing of high-power electron tubes and lasers in an industrial plant. Measurements of electric and magnetic fields were done using both commercially available and laboratory-developed instrumentation. Isotropic H-field sensors were developed to allow quantitative evaluation of high-intensity magnetic fields. Ten induction heaters with nominal A.C. power ranging from 2.5 kW to 15 kW and operating at frequencies between 300 kHz and 790 kHz were surveyed. Electric field strengths up to 8 kV/m and magnetic field strengths up to 20 A/m were measured.

Environmental Exposure↗
PubMed1988

Structural modifications and biological compatibility of doped bio-active glasses.

The Raman laser and infrared spectra of doped bio-active glasses of the 45S5 type are presented and discussed. The spectroscopic results show that the doping agents cause the destruction of the basic glass structure and the consequent formation of SiO4(4-) units in the glass network. When the doped glasses have been immersed in a physiological solution (199 medium), a film of calcite forms on the glass surface and this modification is related to the type of doping agent used, decisive for close linking between metal supports and the glass. The presence of doping agents does not prevent the normal growth of the bone onto the surface of doped bioactive glasses. Histological tests show that tissue response to very fine powders of doped glasses increases up to 15 days more or less according to the structural modifications revealed by spectroscopic measurements.

Animals↗
PubMed1986

Exposure of workers to intense RF electric fields that leak from plastic sealers.

This paper presents the results of an environmental investigation in a plastic-ware industry using RF sealers. Environmental measurements have demonstrated the presence of strong electric fields the intensity of which: reaches significant levels from the health-protection point of view only in proximity to the applicators; often exceeds the maximal levels allowed by all standards (including the most permissive) for short duration exposures, especially in the region of the hands. Results of a cross-sectional study on the health of 63 female workers are related to the observed RF exposure. A statistically significant correlation was found to exist between RF exposure and some minor health effects--eye irritation, upper limb paresthesias, and vitreous body disorganization.

Equipment Safety↗
PubMed1985

Thermal haemolytic threshold of human erythrocytes.

Haemolytic thermal threshold of human erythrocytes has been determined by means of an especially designed microwave apparatus. Temperatures between 50 and 55 degrees C are necessary to produce an initial haemolysis of erythrocytes in the whole blood, while the thermal threshold drops to 37 degrees C for red blood cells suspended in buffered saline. Absorbed energy measurements permit the conclusion that the haemolytic effect is thermal in nature.

Erythrocytes↗
PubMed1985

The importance of the angle of anteversion in the development of arthritis of the hip.

The angle of anteversion, assessed by the Dunlap technique, was determined in 30 patients suffering from primary osteoarthritis of the hip. This was compared with the same angle in 10 normal subjects. The patients with arthritis showed a statistically significant increase in the angle. This is considered by the authors to play a significant part in the pathogenesis of primary osteoarthritis of the hip.

Adult↗
PubMed1984

Arthroprosthesis in old unreduced congenital dislocation of the hip, using the "false" acetabulum. A study of 34 cases.

In adult patients with considerable loss of function due to an unreduced congenital dislocation of the hip with a false acetabulum, the authors posed the question "Is it feasible, with a reasonable chance of success, to perform an arthroprosthesis in the "pathological" position, using the false acetabulum as a seating for the cup?" The aim of this study was to assess, in particular, the holding properties of the cup which has to be fitted after appropriate reaming, into this rather precarious false acetabulum. They define the indications for this procedure and describe their technique. The results of 34 operations, followed up for an average of 5 years, confirm the validity of this procedure.

Acetabulum↗
PubMed1983

Mineral alterations in senile osteoporosis.

This research investigates the occurrence of involutional processes of mineral transformation in elderly patients with clinical, radiographic and histological signs of senile osteoporosis. The decreased ability to withstand static and dynamic stresses proved to be associated either with the quantitative reduction in trabeculae or with the altered morphology of hydroxyapatite (HA) crystals. This variation produces a non-homogeneous mineral distribution which leads to a substantial alteration of the system of the stress lines producing mechanical bone behaviour. This altered distribution in mineral density has been attributed to the dynamic loss of balance between osteoblastic and osteoclastic activity; this is believed to be a peculiarity of senile osteoporosis.

Adult↗
PubMed1983

Composite acrylic cement with added hydroxyapatite: a study of the polymerization temperature.

Varying percentages (0 to 50%) of crystalline hydroxyapatite (HA) in powder form were added to ordinary acrylic cement (PMMA). The exothermic peak of the polymerization reaction and the setting time of this compound cement were investigated. Its mechanical properties are far superior to those of ordinary cement. The addition of small percentages of HA to acrylic cement produces a sharp fall in the exothermic polymerization peak; it also increases the setting time, although this remains within time limits that are only slightly greater than those for ordinary cement.

Bone Cements↗
PubMed1978

Secondary treatment of fractures of the middle and lower third of the tibia unsuccessfully treated by primary internal fixation.

The authors present forty six cases, referred to us between 1969 and 1974, of fracture of the middle and lower thirds of the tibia, previously treated elsewhere by primary internal fixation using a plate and screws. The causes of failure are divided into defective indications and defective technique. The methods of treatment used in infected and non-infected lesions are described. They criticise the unnecessary use of plates and explain their reasons. They do not condemn the method outright, since in selected cases IT IS UNDOUBTEDLY A VALID METHod of treatment. They are opposed, however, to its indiscriminate use for lesions that may perfectly well be cured, with the minimum risk, either by conservative methods, or by intramedullary nailing.

Fracture Fixation, Internal↗
PubMed1977

[Evaluation split renal function and compensatory hypertrophy using a radio-isotopic technique].

Using a new method for the determination of split renal function with a radio-isotopic technique (FG Hipaque I131 and PRP Hippuran I131) we sought to determine residual renal function with pre-operative studies, especially in preparation for nephrectomy, and secondly with postoperative studies of compensatory renal hypertrophy after total or partial nephrectomy and the restoration of function in the kidneys following surgery of the urinary tract. A total of 20 cases was studied. We noted marked compensatory hypertrophy after total and partial nephrectomy and the prompt return of function after procedures involving the urinary tract, on condition that any acute infection be prevented.

Adult↗
PubMed1976

Haemangioma of bone with radiographic appearances simulating a giant cell tumour.

A case is described of haemangioma of the proximal end of the humerus which simulated a giant cell tumour on radiography. An attempt at biopsy, carried out elsewhere, had failed because of severe haemorrhage from the tumour during operation. It was treated by en bloc resection and endoprosthesis with a good result after one year.

Bone Neoplasms↗