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Biomedical subjects

G Monticelli

Publications and source records attributed to G Monticelli.

At least 19 recordsLinked to original sources
PubMed1990

Indications for early surgery in cases of lumbar and dorsolumbar scoliosis: the role of vertebral rotation.

There are very few objective criteria for the choice between conservative and surgical treatment of lumbar and dorsolumbar scoliosis ranging from 40 to 50 degrees. We reviewed the long-term results obtained in 76 patients treated with plaster braces because they had refused surgical treatment; in 56% of the cases a nearly 10 degree gain was maintained after the onset of treatment; all of the cases which showed improvement presented a reduction in the curve by at least half and rotation by at least one-third in tests in suspension or in bending, and this was maintained in plaster. In cases where the long-term results were poor, however, rotation did not change. In conclusion, of the many parameters examined, only a combined assessment of the reducibility of both the Cobb angle and of rotation provides a valid indication for the treatment of lumbar and dorsolumbar curves ranging from 40 to 50 degrees.

Adolescent↗
PubMed1987

Role of hyperthermic perfusion in the treatment of limb osteogenic sarcoma.

The role of hyperthermic perfusion (HP) for the treatment of limb osteogenic sarcoma was evaluated in 76 patients. Twelve patients were treated with HP alone, and a 5- and 10-year survival rate of 25.5% was obtained. When amputation was systematically associated to HP (12 patients), a 5- and 10-year survival rate of 50.9% was achieved. Twenty-seven patients were treated with hyperthermic antiblastic perfusion (HAP) followed by amputation 4 weeks later. With this treatment, the 5- and 10-year actuarial rates rose to 71.4 and 65%, respectively, with a 5-year disease-free survival rate of 67.4%. Fifteen patients were treated with HAP followed by an 'en bloc' resection and bone reconstruction. The 5- and 10-year actuarial survival rate obtained was 63.5% with a 5-year disease-free survival rate of 53.6%. These results seem to indicate that HAP permits carrying out conservative rather than ablative surgery for the treatment of limb osteogenic sarcoma.

Actuarial Analysis↗
PubMed1986

Segmental amputation with re-implantation in the treatment of malignant bone tumours of the limbs.

Stage 2 B malignant skeletal tumours are currently treated by amputation or disarticulation of the limb. The present paper describes a surgical technique for complete removal of the neoplasm and surrounding soft tissues by resection of a cylinder of the limb complete with skin. The resection of bone and adjacent soft tissues is extended sufficiently proximal and distal to the neoplasm to ensure complete removal of neoplastic tissue. The authors describe two cases; an osteosarcoma of the distal third of the femur and a malignant fibrous histiocytoma of the lower radius. After removing the affected cylinder of the limb, osteosynthesis is performed by one of a variety of methods. The main vessels and nerves are dealt with according to the findings revealed by pre-operative investigations or per-operative findings. If they have to be sacrificed, end to end suture is performed, but if main nerves can safely be spared (as in Case 1) it greatly enhances the functional prognosis. The value of this operation is that it is as radical as amputation while the aesthetic and functional results are equivalent to those of a resection-arthrodesis. The operation has therefore been designated segmental amputation.

Adult↗
PubMed1985

The colon of Leucophaea maderae: fine structure and physiological features.

The colon of L. maderae consists of a single columnar epithelium covered with a cuticle and of a musculo-connective sheath. The apical plasma membranes form a system of leaflets with numerous mitochondria inserted in association with microfilaments. Lateral plasma membranes are linked together by junctional complexes consisting of a zonula adherens and a long convoluted septate junction of the pleated type. In the basal region of the cell, numerous membrane infolds and scattered scalariform junctions with associated mitochondria are present. These cell specializations are typical of arthropod transporting organs, being distinctive features of ion and fluid transporting epithelia. The isolated colon exhibited a transepithelial electrical potential difference (PD) of about 100 mV, lumen side positive with respect to the haemolymph side. The PD was almost abolished by metabolic inhibitors, it was reduced by acetazolamide and SITS, and it was unaffected by ouabain. These effects suggest that HCO3- and Cl- are involved in the genesis of the PD, whereas Na+ is not directly responsible of the PD. Measurements of Na+ and Cl- fluxes across the colon wall confirm that Na+ moves following the PD across the tissue, while Cl- movement occurs against an electrochemical potential difference. The electrical profile of the epithelial cells is of the well type and it suggests that the primary or secondary active step for Cl- transport across the epithelium should be located at the mucosal border of the cell.

Animals↗
PubMed1985

Interrelationships between the phase diagrams of the two-component phospholipid bilayers.

Basic relationships between the phase diagrams, previously considered independent of each other, are described. Phase diagrams of two-component phosphatidylcholine/phosphatidylcholine (PC/PC), phosphatidylethanolamine/phosphatidylethanolamine (PE/PE), and PC/PE lipid membranes are systematically investigated by means of the Landau theory. While gradually changing the chain length of one of the components, a characteristic peritectic-miscible-azeotropic-semiazeotropic-eutectic (P-M-A-S-E) series of the phase diagram was found in the PC/PE system and a peritectic-miscible-one-component-miscible-peritectic (P-M-O-M-P) series was found in the PC/PC and PE/PE systems. These serial catastrophic changes in the phase diagrams could be explained by the fusion and birth of the mixed phase regions in the phase diagram. Finally when we constructed the superdiagrams, we obtained all of the possible series of the phase diagrams in a wide class of the two-component mixtures. Moreover, one can predict the type of the phase diagram when the components r and p contain equal-length saturated hydrocarbon chains. Depending on the relationships between the chain lengths (L, Lp) and that on the phase transition temperatures of the pure components (Tr, Tp), the system is: miscible (M), if 0 < Tr(L) - Tp(L) < 5 degrees C and L -Lp > 0, azeotropic (A), if 0 < T,(L) - Tp(L) < 5 degrees C and L -Lp < 0, peritectic (P), if T,(L) - Tp(L) > 40 degrees C and L -Lp - 0, eutectic (E), if Tr(L) - Tp(L) >40 degrees C and L - Lp <0,while it is M or P if 5 degrees C< Tr(L) - Tp(L) <40 degrees C and L - Lp>-0,and E,S,or Aif 5 degrees C < Tr(L) - Tp(L) < 40 degrees C and L,-Lp < 0.

Lipid Bilayers↗
PubMed1984

The behaviour of apatite-based ceramics in relation to the critical 1150 degrees-1250 degrees C temperature range.

Characterization of synthetic calcium phosphates is reported and compared with previous studies. Barium hydroxyapatite was also synthesized. Shrinkage on sintering, water absorption, tensile strength, porosity and X-ray diffraction patterns were studied. Hydroxyapatite and beta-tricalcium phosphate show compositional and mechanical property variation dependent on sintering temperatures. The property change on introduction of barium removes the practical value. X-ray diffraction analysis is considered essential before clinical use due to sensitivity of composition to sintering conditions.

Barium Compounds↗
PubMed1983

Resection and reconstruction of the distal end of the femur or proximal end of the tibia after radical excision of diaphyseal and epiphyseal segments.

The authors describe a technique of bone reconstruction after radical resection of bone segments from the distal end of the femur or proximal end of the tibia. This involves the insertion of an intramedullary nail of predetermined length which is fixed to the bone by screws applied at the proximal and distal ends of the nail. An aiming device is used which permits the screws to be applied by a closed procedure. The reconstruction is effected by using the diaphysis of the contralateral fibula, which is divided longitudinally into two halves. These are then applied laterally and medially to the endomedullary nail at the site of the resected area. Grafts of cortico-spongy bone taken from the iliac crests are inserted between the two fibular hemidiaphyses. The authors give a detailed description of the operation and report the clinical results obtained in eleven cases and the complications observed.

Adolescent↗
PubMed1979

Membrane water permeability alterations induced by pollutants.

Lead ions and the surfactant nonylphenolethoxylate are found to inhibit the active transport-coupled water flow in the leg skin of Rana esculenta. The water permeability for osmotically driven flows remains unchanged for high flows, while it is remarkable lowered near zero osmotic pressure difference. The possible mechanism of the permeability change is discussed in connection with the available data on the electrophysiological effects of the pollutants.

Animals↗
PubMed1978

Non linear volume flow dependence on osmotic pressure difference in frog skin.

The volume flow dependence upon the osmotic pressure difference of both impermeant (sucrose) and permeable (NaCl) species has been investigated in leg skin bags of Rana esculenta. It is concluded: 1. The hydration-dehydration error in the flow measurement with leg skin bags is negligible. 2. The flow-force relationship is non-linear. 3. Unstirred layers and solute permeation have little, if any, influence on non linearity. 4. Structural modifications of the skin induced with hypertonic solutions have been observed and may contribute to non linearity, as well as the multiple-barrier effect.

Animals↗
PubMed1976

Intertrochanteric femoral osteotomy with concentric reduction of the femoral head in treatment of residual congenital acetabular dysplasia.

A method of classification based upon increase of the anteversion and valgus deformity of the upper femur associated with a dysplastic acetabulum and subluxation of the femoral head demonstrates 4 main groups: I or II in patients 1 to 3 years of age; III, patients approximately 2 years of age; IV, patients with absolute contraindication for surgical intervention. The Monticelli technique employs a Kirschner wire for the internal fixation and incorporates it in a hip spica. The results of the surgical treatment are very gratifying when classification and specified indications are correct. In follow-up observations ranging from 3 to 11 years, with an average of 7 years, there were practically no complications other than a few superficial skin infections.

Acetabulum↗
PubMed1975

Sodium chloride reflection coefficient in rabbit gall bladder.

By means of the Kedem-Katchalsky thermodynamic description of active transport, a relationship has been derived between the apparent reflection coefficient and the Staverman reflection coefficient for passive transport of a solute which is both actively and passively transported. The relationship between volumetric flow and its driving forces, containing the Staverman reflection coefficient, was tested for sodium chloride in rabbit gall bladder and the reflection coefficient was evaluated.

Animals↗
PubMed1975

Spondylolysis and spondylolysthesis.

On the basis of our own experience and the most up-to-date reports, we present some of the most controversial features of spondylolysis and spondylolisthesis. In particular, the importance of stress in the etiology of the lysis has been revealed by research carried out on athletes practicing strenuous sports. It has also been shown how the slipping of the olisthesic vertebra does not necessarily cease around the age of 20, but may continue, under certain conditions, even in the young adult. Finally, advice on treatment is given in relation to the various surgical techniques, emphasizing the importance of the reduction of slipping, and giving directions on the use of this technique, and its limitations.

Adolescent↗