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Biomedical subjects

A Tinti

Publications and source records attributed to A Tinti.

At least 19 recordsLinked to original sources
PubMed2005

Comparison between the in vitro surface transformations of AP40 and RKKP bioactive glasses.

Two bioactive silica-phosphate glasses, AP40 and RKKP, were compared in their behaviour in simulated biological environment. Their chemical composition is practically identical, except that RKKP contains small amounts of amphoteric network-former oxides Ta2O5 and La2O3 (composition in wt% for AP40: beta-Ca3(PO4)2 24.50, SiO2 44.30, CaO 18.60, Na2O 4.60, K2O 0.19, MgO 2.82, CaF2 4.99; RKKP: beta-Ca3(PO4)2 24.23, SiO2 43.82, CaO 18.40, Na2O 4.55, K2O 0.19, MgO 2.79, CaF2 4.94, Ta2O5 0.99, La2O3 0.09). Previous investigations showed a better performance in osteopenic bone for RKKP. To gain more insight into these differences in biological behaviour, the in vitro bioactivity of the glasses was studied by treatment with a continuously replenished Hanks' Balanced Salt Solution (HBSS). The glasses were examined before and after HBSS treatment for 20 and 40 days by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Energy Dispersion (EDX), Raman and IR vibrational spectroscopies. Some slight but notable differences between the two glasses were observed after HBSS treatment. IR and EDX analyses showed that deposits formed on both glasses were composed of a calcium deficient carbonate-apatite; however, the layer formed on RKKP glass was found to be slightly more calcium deficient and thinner. EDX analysis evidenced the presence of a small percentage of F- ions only in the layers formed on the RKKP samples. The differences disclosed, although slight, can contribute to the understanding of the different biological behaviour previously observed.

Biocompatible Materials↗
PubMed2003

1H-NMR and 13C-NMR lipid profiles of human renal tissues.

Lipids from human renal tissues are studied by means of (1)H- and (13)C-NMR spectroscopy. The total lipid fractions obtained from healthy kidneys, malignant renal cell carcinomas, and benign oncocytomas are characterized and analyzed to elucidate the main differences between the functional and neoplastic tissues. In all cases the lipid components are well identified. The healthy kidney is characterized by high amounts of triglycerides and the presence of cholesterol in its free form. On the contrary, renal cell carcinomas contain high amounts of cholesterol that are almost completely esterified as oleate, suggesting an intracellular localization of the cholesteryl esters synthesis. Cholesteryl esters are considered markers of renal cell carcinomas, thus supporting recent theories that these compounds play a leading role in cell proliferation. Oncocytomas are particularly rich in phosphatidylcholine and, analogous to the healthy kidney, are completely lacking in cholesteryl esters. Healthy kidneys and oncocytomas appear to have other similarities if compared with renal cell carcinomas: a very high fatty acyl/cholesterol ratio, the presence of dolichols, and a higher grade of unsaturation. The (13)C data suggest a new method for the direct evaluation of the saturated/unsaturated fatty acyl ratio.

Carcinoma, Renal Cell↗
PubMed2003

Detachment of titanium and fluorohydroxyapatite particles in unloaded endosseous implants.

The shape, surface composition and morphology of orthopaedic and endosseous dental titanium implants are key factors to achieve post-surgical and long-term mechanical stability and enhance implant osteointegration. In this study a comparison was made between 12 titanium screws, plasma-spray-coated with titanium powders (TPS), and 12 screws with an additional coating of fluorohydroxyapatite (FHA-Ti). Screws were implanted in the femoral and tibial diaphyses of two mongrel sheep and removed with peri-implant tissues 12 weeks after surgery. The vibrational spectroscopic, ultrastructural and morphological analyses showed good osteointegration for both types of implants in host cortical bone. The portion of the FHA-Ti implants in contact with the medullary canal showed a wider area of newly formed peri-implant bone than that of the TPS implants. Morphological and EDAX analyses demonstrated the presence of small titanium debris in the bone medullary spaces near the TPS surface, presumably due to the friction between the host bone and the implant during insertion. Few traces of titanium were detected around FHA-Ti implants, even if smaller FHA debris were present. The present findings suggest that the FHA coating may act as a barrier against the detachment of titanium debris stored in the medullary spaces near the implant surface.

Animals↗
PubMed2002

Effects of the sterilisation method on the wear of UHMWPE acetabular cups tested in a hip joint simulator.

Ultra-high molecular-weight-polyethylene is the most commonly used bearing material in total joint replacement. Wear of polyethylene is a Serious Clinical problem that limits the longevity of orthopaedic implants. Information on degradative changes in the material properties and on the methods used for the sterilisation of polyethylene may help in the selection process of orthopaedic implants with the best wear resistance. This study was performed to investigate the effects of the sterilisation method (gamma irradiation and ethylene oxide treatment) on the wear and on the changes in physical properties of polyethylene acetabular cups. At this purpose, gamma-sterilised and ethylene oxide (EtO)-sterilised acetabular cups were tested against CoCr femoral heads in a hip joint simulator run for 5 million cycles in bovine calf serum. The crystallinity of the cups was evaluated by micro-Raman spectroscopy as a function of the inner surface position. The partial least square calibration was used to correlate the Raman spectra with the crystallinity of the polymer measured by differential scanning calorimetry. The analysis performed on soak control acetabular cups demonstrated that the gamma-sterilised cups are significantly more crystalline than the EtO-sterilised ones. The mean crystallinity values obtained for the gamma-sterilised and EtO-sterilised soak control cups were 65.0% and 63.4%, respectively. Weight loss measurements revealed that the gamma-sterilised acetabular cups exhibited a lower wear rate than that by EtO-sterilised. Thc Raman results obtained on gamma-sterilised and EtO-sterilised acetabular cups showed that the changes in surface crystallinity were mainly caused by irradiation rather than by the mechanical friction during the in vitro tests.

Analysis of Variance↗
PubMed2002

Molecular characterization of human healthy and neoplastic cerebral and renal tissues by in vitro (1)H NMR spectroscopy (review).

The clinical impact of (1)H NMR spectroscopy in the study of human organs, brain and kidney in particular, is well demonstrated. The in vitro (1)H NMR technique is a powerful tool for monitoring changes in intracellular metabolites of human normal and neoplastic cerebral and renal tissues. Healthy and tumoral tissues of different histologic types have been fully characterized from a biochemical standpoint. Molecular characterization is performed on both the aqueous and lipid extracts of surgically removed tissue biopsies yielding a full picture of tissue biochemistry. These analyses have disclosed markers of healthy brain and kidney and of their respective neoplastic lesions. Moreover, some biochemical features can differentiate neoplasms within the same histological type. In particular, lipidic components, like cholesteryl esters (namely oleate), detected in highest grade tumors, warrant further investigation. A better understanding of the biochemistry of diseased human tissues could open the way to new diagnostic and treatment strategies.

Brain Neoplasms↗
PubMed2001

Characterization of lipids from human brain tissues by multinuclear magnetic resonance spectroscopy.

Multinuclear ((1)H, (13)C, and (31)P) magnetic resonance spectroscopy are applied to the biochemical characterization of the total lipid fraction of healthy and neoplastic human brain tissues. Lipid extracts from normal brains, glioblastomas, anaplastic oligodendrogliomas, oligodendrogliomas, and meningiomas are examined. Moreover, the unknown liquid content of a cyst adjacent to a meningioma is analyzed. Two biopsies from glioblastomas are directly studied by (1)H-NMR without any treatment (ex vivo NMR). The (1)H- and (13)C-NMR analysis allows full characterization of the lipid component of the cerebral tissues. In particular, the presence of cholesteryl esters and triglycerides in the extracts of high grade tumors is correlated to the vascular proliferation degree, which is different from normal brain tissue and low grade neoplasms. The (31)P spectra show that phosphatidylcholine is the prominent phospholipid and its relative amount, which is higher in gliomas, is correlated to the low grade of differentiation of tumor cells and an altered membrane turnover. The ex vivo (1)H-NMR data on the glioblastoma samples show the presence of mobile lipids that are correlated to cell necrotic phenomena. Our data allow a direct correlation between biochemical results obtained by NMR and the histopathological factors (vascular and cell proliferations, differentiation, and necrosis) that are prominent in determining brain tumor grading.

Brain Chemistry↗
PubMed2001

Congenital defect in the abdominal wall in an adult: a case report.

We describe a rare case of a woman aged 38 who presented with an untreated omphalocele in association with a duplication of the vena cava and malposition of the right kidney. An aesthetic and functional reconstruction of the abdomen was achieved with local flaps and the creation of a neoumbilicus.

Abdominal Muscles↗
PubMed2000

Vibrational spectroscopic characterization of new calcium phosphate bioactive coatings.

In this work calcium phosphate (CaP) compounds with different PO(3-)(4)/HPO(2-)(4) R molar ratios in the 0.65-149 range were synthesized. In fact, all these CaPs contain different amounts of HPO(2-)(4) and PO(3-)(4) ions as well as the amorphous precursors (tricalcium phosphate and octacalcium phosphate) of hydroxyapatite deposition, which was shown by in vitro and in vivo measurements. Spectroscopical IR and Raman results showed the presence of bands whose intensity ratio can be related to the molar ratio R; in particular, the Raman I(962)/I(987) and the IR I(1035)/I(1125) intensity ratios were characterized as markers of the molar ratio. For these CaP compounds a nucleation model, which was based on the ability of HPO(2-)(4) ions to form strong H bonds with PO(3-)(4) ions, was proposed.

Calcium Phosphates↗
PubMed1997

[Pre- and postoperative color Doppler ultrasonography of myocutaneous flaps in reconstructive surgery of the breast].

The authors present their experience in the study of blood supply of flaps. The machine used to study both pre and postoperatively the myocutaneous flap is the echo-color Doppler, a brand new device which has recently been used in investigating the morphology and the blood supply. The use of such method has provided us with the following information: detailed ultrasound structure of the skin, subcutaneous and muscular tissues of the examined flap; localization of vessels within the flap; size of the vessel in its whole length; quality and speed of both the arterial and venous flow. Such information is very important for the surgeon to plan in detail the reconstruction by knowing the blood supply of myocutaneous flap.

Breast↗
PubMed1997

[Use of Doppler color ultrasonography in the microsurgical treatment of idiopathic varicocele].

The aim of this paper is to evaluate the role of Doppler and echo color-Doppler in the microsurgical treatment of varicocele. Since December 1993, 87 consecutive patients underwent microsurgical treatment of varicocele. The study demonstrates that Doppler and Color-flow-Duplex scanning provide an accurate, non-invasive method to identify the position of accessory spermatic veins, evaluating at the same time the flow characteristics of the microsurgical anastomosis.

Evaluation Studies as Topic↗
PubMed1995

Preoperative and postoperative evaluation of latissimus dorsi myocutaneous flap vascularization by color flow duplex scanning.

At the Plastic and Reconstructive Surgery Department of the University of Perugia, 104 patients have been examined by color flow duplex scanning in order to study latissimus dorsi vascular supply before and after surgical procedures. This noninvasive ultrasound technique provides a precise and accurate measurement of blood flow velocity (15 cm/s) and volume (27 ml/min) within the thoracodorsal artery, which represents the vascular pedicle of the flap, and it allows us to detect the exact location of the perforating branches with their cutaneous distribution. This preoperative evaluation, pointing out vascular pathologies that contraindicate use of the latissimus dorsi flap, can be considered a great help for the reconstructive surgeon in the choice of the most suitable operation, and it can surely lead to a significant decrease in postoperative graft failure rates.

Adolescent↗
PubMed1995

Colour flow duplex scanning: an accurate, non-invasive technique for preoperative evaluation of the vascular supply of the rectus abdominis myocutaneous flap.

Forty patients were examined with colour Doppler to study the vascularization of rectus abdominis myocutaneous flaps before operations. The accuracy of this non-invasive ultrasound technique allowed us to describe the characteristics of the blood flow, including volume and velocity, diameter of vessels and their transverse section area within the epigastric arteries which supply the superior and inferior vascular pedicles of the flap. Vessels are drawn on the skin surface so that the flap can be more precisely and rapidly dissected. We are now using colour Doppler to assess variations in the diameter of vessels and in other variables of blood flow within the vascular pedicle of the transferred flap. These evaluations before and after operation are a great help to the reconstructive surgeon in the choice of operation and will lead to an appreciable reduction in postoperative morbidity.

Abdominal Muscles↗
PubMed1995

[RS3PE syndrome. A new rheumatic inflammatory syndrome in advanced age].

RS3PE syndrome (Remitting Seronegative Symmetrical Synovitis with Pitting Edema) is a new form of arthritis in the elderly, characterized by symmetrical polysynovitis of acute onset associated with distal pitting edema. Tests for serum IgM rheumatoid factor are typically negative. RS3PE syndrome affects Caucasians aged over 60, predominantly males. It has a benign course and remits completely without residua.

Aged↗
PubMed1994

Synovial fluid parameters in normal and osteochondritic hocks of horses with open physis.

An investigation was carried out on most common synovial fluid parameters of normal and osteochondritic hocks of horses less than 12 months old in order to confirm the presence of an inflammatory process. Furthermore, a spectroscopic study was performed on synovial fluid from both normal and diseased hocks. A depolymerization of hyaluronic acid was demonstrated in synovial fluid from diseases joints, similar to that reported in human rheumatoid arthritis. A one month rest seem to normalize all parameters considered and in one joint, a return to normal infrared spectrum was demonstrated.

Age Factors↗
PubMed1992

Raman spectroscopy in the study of biocompatibility.

This review deals with the application of Raman spectroscopy to the study of the biocompatibility of orthopaedic and ophthalmological materials and includes an introduction, a brief theory on the fundamental concepts of the technique, a description of the method and of the traditional and non-traditional instrumentation and a brief treatment of the surface properties of the different classes of materials. In the orthopaedic field, Raman studies on the structures of glasses, ceramic materials, carbon fibres and polymers before and after implantation are reviewed, particularly as far as structural modifications at the biomaterial-tissues interface are concerned. In the ophthalmological field, the chemical biocompatibility of hydrophobic and hydrophilic polymers for intraocular and intrastromal implants and for soft contact lenses is considered with respect to the presence of monomeric reactive centres in hydrophobic materials and the water amount in hydrophilic ones. The progress of the multichannel Raman technique for 'in-vivo' measurements is also described.

Biocompatible Materials↗
PubMed1991

Calcium phosphate materials containing alumina: Raman spectroscopical, histological, and ultrastructural study.

Variable alumina quantities were added to two types of calcium phosphate materials-hydroxyapatite ceramics with Ca/P = 1.67 and calcium metaphosphate glass with Ca/P = 1--in order to increase their mechanical properties. Raman spectroscopy shows that alumina interacts with the phosphate group of these materials, while thermomechanical analysis shows that their elastic modulus has a value similar to that of bone. Histological sections demonstrate that the surface in close contact with ceramic materials shows a good integration between bone and biomaterial. All ceramic specimens are penetrated by well-stained, presumably glycoprotein, matrix, that consistently forms a thin network in close contact with the implant. After 6 weeks bone growing on both ceramic and glass shows signs of maturation with a lamellar structure and an apparently normal mineralization. In the case of the glass, inside this newly formed bone, were often observed two layers, the internal one showing a well defined lamellar structure.

Aluminum Oxide↗
PubMed1989

Raman spectroscopy for the study of porous composite alumina coating.

A new acetabular cup prosthesis made of alumina and bioactive glass was studied and evaluated using nondestructive and noninvasive Raman laser spectroscopy. The prosthesis consists of an alumina socket coated with a double layer of alumina beads bonded to the prosthesis with a layer of glass. Raman spectroscopy showed that both the socket and the beads are composed of alpha-Al2O3 (corundum), while the bioactive glass (alkaline and alkaline earth alumosilicate with a small quantity of zirconium oxide) showed this to have an intermediate structure between that of vitreous silica and that of the alkaline and alkaline earth disilicate glasses. The Raman spectra of the contact surfaces between the bioactive glass and the alumina of the assembled prosthesis and of an alumina disk coated with the same glass showed the presence of new bands which may be correlated with a chemical interaction between the components of the prosthesis.

Aluminum↗