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Biomedical subjects

S Gnudi

Publications and source records attributed to S Gnudi.

At least 55 records · Page 3Linked to original sources
PubMed1988

The effects of methotrexate (MTX) on bone. A densitometric study conducted on 59 patients with MTX administered at different doses.

The bone density of two groups of patients with osteosarcoma treated with high and low doses of MTX is compared with that of a group of healthy subjects of the same age. Bone density was measured in the radius at the mid point and at the trabecular distal point. In the patients treated with low doses there were differences in bone density as compared with the controls. In those treated with high doses the bone mineral content values were significantly lower than those for the controls (p greater than 0.01) at the trabecular distal point but not at the mid point. The significant reduction in BMC in patients treated with high doses indicated that the osteopaenic effect is dose-dependent. The decrease in density only at the site at which trabecular bone is prevalent shows that MTX acts mainly at the level of this type of bone in accordance with the proven greater sensitivity of trabecular bone to the action of other osteopaenic agents.

Adolescent↗
PubMed1984

Contribution to the diagnostic study of pulmonary embolism occurring as a complication of operations for the insertion of hip prostheses.

The authors report the clinical, electrocardiographic and radiological aspects of pulmonary embolism as a post-operative complication which occurred in 46 patients after total hip replacement. They discuss the relative value of their findings in relation to arriving at a correct diagnosis, which they believe should be possible without recourse to more complicated procedures such as the use of contrast media radiography.

Blood Gas Analysis↗
PubMed1983

Thromboembolism in total hip replacement.

The efficacy of low dosage heparin in the prevention of pulmonary embolism has been assessed in a group of 177 "high risk" patients undergoing hip replacement operations compared with a control group of 236 "high risk" patients not so treated. The diagnosis of pulmonary embolism was made on the basis of the commonly accepted clinical signs and symptoms, confirmed by electrocardiography, chest radiography, serum enzymes, and blood gas analysis. Pulmonary embolism occurred in 9.74% of the patients in the control group and in 1.69% of those treated with heparin. These figures indicate that heparin is effective in preventing pulmonary embolism.

Aged↗
PubMed1982

Solitary plasmacytoma of the vertebral column. A report of 15 cases.

The clinical features and the treatment results of 15 patients with solitary plasmacytoma of the spine observed in a 28-year period (1950-1977) are reported. The signs at presentation were back pain in 4 cases and spinal cord compression in 11 cases. Three of these patients had paraplegia. Radiologically, the alteration encountered was an osteolytic lesion in all cases. The local treatment was radiotherapy in 11 cases and surgery plus radiotherapy in 4 cases. In 3 patients systemic chemotherapy was also employed. Seven patients are alive without signs of disease 3 to 9 years (mean 6 years) after diagnosis. Eight patients developed multiple myeloma in a period ranging from 1 to 8 years (mean 3.5 years). The relationship between multiple myeloma and solitary plasmacytoma of the spine, as well as the best treatment for the latter, are discussed.

Adult↗
PubMedDate not supplied

Loss of bone mass after total hip replacement: preliminary data.

In a total of 37 females with cemented total hip replacement for monolateral coxarthrosis, of which 13 with prosthetic stem loosening, and 11 with monolateral coxarthrosis that is not prosthetized, bone mineral density (BMD) is determined by dual ray photonic absorbimetry selecting regions of interest (ROI) on the cortex of the femurs 4 cm under the lesser trochanter and on the ischium bilaterally. In females that are not prosthetized there are differences in bone mass between the two femurs and the ischium on both sides. In prosthetized patients BMD of the femur and of the ischium on the side operated on is significantly less than on the contralateral one (Student's "t" test: p < 0.001). In patients with stable prostheses, BMD of the femur operated on is greater than that in females with prosthetic stem loosening (Student's "t" test: p < 0.000). Based on a comparison between these two groups we did not observe any other significant differences in BMD among the ROI analyzed. BMD was correlated with the amount of time since surgery only in the ROIs in prosthetized femurs. The study confirms the significant bone resorption of the cortex in prosthetized femurs and documents analogously significant reduction in BMD in the ischium on the side operated on. Finally, it indicates that prosthetic stem loosening may be associated with loss of BMD in the femoral cortex which is significantly greater than that observed, during analogous periods of time in stable implants.

Aged↗
PubMedDate not supplied

Fracture prediction for the femoral neck using finite element models.

Fracture of the femoral neck is an important clinical, social and economic topic. Prediction in subjects who are at risk for this type of fracture has been the object of numerous studies. Nonetheless, the methods of classification based on densitometric indicators alone have shown poor accuracy. It is the purpose of this study to propose a method to obtain an estimate of the resistance of the proximal femur, and to improve accuracy in prediction in subjects who are at risk for fracture. Based on the densitometric dataset alone, a bidimensional finite element model was developed that takes into account the distribution of density together with the femoral anatomy and the typical conditions of trauma. The model was applied to a group of preliminary osteoporotic patients. The statistical classification showed an increase in accuracy by 13%, as compared to a classification based on densitometric indicators alone.

Adult↗
PubMedDate not supplied

The femoral distal epiphysis of ovariectomized rats as a site for studies on osteoporosis: structural and mechanical evaluations.

OBJECTIVE: To investigate in detail the mechanical and structural characteristics of cancellous bone from the femoral distal epiphysis of normal and ovariectomized rats, and to provide reference values in order to improve experimental research on osteoporosis by characterising an alternative and complementary anatomic site. METHODS: 40 female Sprague-Dawley rats (10 months old) were randomly divided into 4 groups of 10 each: baseline, ovariectomized (Ovx), sham-operated (Sham-Ovx) and sham-aged (Sham-Aged). Baseline animals were sacrificed at the beginning of the study. Ovx and Sham-Ovx animals were sacrificed 16 weeks after surgery, whereas Shamaged rats were killed when aged 14 months. Femurs were excised and densitometric, ultrasonographic, mechanical and histomorphometric analyses were performed. RESULTS: When comparing the Ovx group with the others, ultrasonographic and densitometric measurements showed significant decreases (p < 0.0005) amounting to 3-5% in the amplitude dependent speed of sound (AD-SOS) and 13-20% in the BMD, respectively. Significant decreases were also seen in the femoral condyle Max. Load (28-31%; p < 0.0005) and Elastic Modulus (19-25%; p < 0.005) in the Ovx group in comparison with the Sham-Ovx and Sham-Aged groups. Histomorphometric analysis showed a significant cancellous bone loss (p < 0.0005). Densitometric (p < 0.01), histomorphometric (p < 0.01) and mechanical (p < 0.05) parameters were correlated with AD-SOS. Among the histomorphometric parameters, stepwise regression analysis showed that the trabecular bone volume (BV/TV) and Max. Load correctly predicted AD-SOS (p < 0.0005) and BMD (p < 0.0005). CONCLUSION: The data from this study characterize osteopenia occurring in the rat distalfemur 16 weeks after ovariectomy and provide methodology and reference values forfurther investigations on osteoporosis and bone-implant osteointegration in osteopenic bone.

Absorptiometry, Photon↗
PubMedDate not supplied

Bone mineral density across the normal rat femour.

The post-ovariectomy osteoporotic rat model is widely used to mimic post menopausal human osteoporosis and to test the efficacy of the therapies used in its treatment An experimental study was performed in order to improve the reliability of bone mineral density (BMD) measurements by correcting also the relocation error. In addition, a BMD map of the whole femur was carried out to detect the areas of uniform density, where the reliability of measuring was improved. Right femurs were taken from 5 Sprague Dawley female rats, 10 months old, and tested every 2 mm from the supracondylar line to the peritrochanteric line (6 scans for each site). Repositioning error was tested for each site of measurement, and measurements done by 3 different operators in a double blind test were compared. At site 4 and 24 (where the differences are high) and site 10 (where the differences of BMD are low) the coefficient of variability (CV) was calculated repositioning the bone after each measurement scan for a total of 6 scans. The CV at sites 4 and 24 were significantly higher than at site 10 (p < 0.05). In our opinion, the bone segment between 8 and 14 mm from the supracondylar line is that which presents the highest homogeneity and where it is preferable to perform the measurements in order to obtain the maximum effect of the method (improvement of precision of about 30%) in comparison with the other femur sites tested.

Absorptiometry, Photon↗
PubMedDate not supplied

Electromagnetic fields in the treatment of postmenopausal osteoporosis: an experimental study conducted by densitometric, dry ash weight and metabolic analysis of bone tissue.

The authors conducted an experimental study on 32 female rats which had been castrated at 10 months of age in order to verify the ability of pulsating electromagnetic fields to prevent osteoporosis induced by surgical menopause. Two different values of intensity of PEMFs were used: 30 G and 70 G. After 4 months of treatment the following testing was done: monophotonic bone densitometry of the lumbar spine, quantitative measurement of the dry ash weight of the femurs, and hematochemical tests to evaluate bone metabolism. The experimental study showed that the PEMFs supplied at 30 Gauss were capable of slowing down the loss of bone mass, while the PEMFs supplied at 70 Gauss obstructed bone decay, providing values for Bone Mineral Density and dry ash weight which were very similar to those observed in the non-castrated control group. Hematochemical tests did not reveal significant variations between the two groups.

Animals↗