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Biomedical subjects

G Ciapetti

Publications and source records attributed to G Ciapetti.

98 records · Page 6Linked to original sources
PubMedDate not supplied

The effects of metal corrosion debris on immune system cells.

Authors evaluated the correlation between immune system and metal ions release in blood of 17 subjects with Cr/Co/Ni joint prostheses. For the purpose Chromium (Cr), Cobalt (Co) and Nickel (Ni) serum levels were measured and, at the same time some immunological parameters (Leukocytes, Lymphocytes and Lymphocytes T, B and Natural Killer cells sub-populations) were evaluated. The results showed a significant decrease of Leukocytes, Lymphocytes and of T Lymphocytes sub-populations. At the same time it was demonstrated a significant increase of Chromium, Cobalt and Nickel levels in patients with joint prostheses as compared to control population (23 patients). In conclusion, ions release from metallic surface of the prostheses is correlated with a depression of immune system. This correlation could depend on a toxic action on immune system caused by the products released by the implant. It could also depend on a lymphocytes compartimentalization in periprosthetic tissues as a consequence of a cell-mediated hypersensitivity reaction towards implants corrosion products.

Adult↗
PubMedDate not supplied

Evaluation of cytokines regulating bone turnover in the serum of post-menopausal and senile women.

The authors evaluated the Insulin-like Growth Factor-1 (IGF-1) stimulating the formation of bone tissue, and interferon gamma (IFN gamma), inhibiting bone resorption, in the serum of women, 13 of fertile age, 34 of post-menopausal age, and 14 of senile age. Values for IGF-1 in the serum were considerably low in patients of post-menopausal and senile age, and presented highly significant differences with values for subjects of fertile age. The values for IFN gamma did not present significant differences between different age groups. It may be assumed that post-menopause and during senile age physiological osteopenia may be favored by a decrease in the secretion of IGF-1.

Adult↗
PubMedDate not supplied

Cellular reactions in hip prosthesis loosening.

Based on the results obtained in histological examinations carried out on periprosthetic tissues in a large series of cases of prosthetic hip joint explants, the authors analyze the cellular events that may occur in loosening phenomena as compared to what occurs in the paraphysiological repair process that is observed in the stable prosthesis. Like other authors, they believe that the principal role in the mechanism of loosening is played by macrophages which are recalled in a large number, at times together with multinucleate giant cells, at the bone-implant interface, after micromovements of the prosthesis and the formation of wear particles have occurred. The macrophages would be capable of favoring resorption of the periprosthetic bone tissue, producing areas of osteolysis in which the transmission of the mechanical stress of loading is modified. The ensuing prosthetic instability increases wear phenomena, causes a greater amount of osteolysis, and, in a vicious cycle, loss of the relationship between bone and implant, and, thus, prosthetic loosening. Finally, the authors report a hypothesis on the pathogenesis of the phenomenon, based on which non-physiological stress, associated with wear and eventually infection, leads to loosening.

Bone Cements↗
PubMedDate not supplied

Histomorphometric evaluation and pathogenesis of prosthetic loosening.

On the basis of a vast experience deriving from the histological study of explants of hip joint prostheses, the authors emphasize the role of histomorphometric testing in allowing for a quantitative evaluation of periprosthetic cellular reaction, of the bone structure, and of the wear phenomena of the implant, in order to gain a better understanding of the pathogenetic mechanisms responsible for the phenomenon of loosening. In agreement with what has been reported by other authors, they describe what they were able to observe by image analysis, microradiography, x-ray diffraction, and microdurimetry in various types of explanted prostheses. In particular, they describe data on the features of the wear particles, the periprosthetic cellular component, the thickness of the interfacial membrane and of the joint neocapsule, the volume of bone-ingrowth, the contact surface, and the structure of the bone-implant interface. Based on the changes observed using histomorphometry, a pathogenetic hypothesis was formulated according to which physical phenomena closely related to the type of implant used, such as wear and metal ion release, and non-physiological stress exerted on the bone, cause a series of cellular chain reactions. Within this context, macrophages, lymphocytes, osteoblasts and osteoclasts are in a continuous state of activation and, both directly and by means of the production of cytokines and other substances, they are responsible for bone resorption and thus loss of continuity between the bone and the implant, resulting in prosthetic loosening.

Hip Prosthesis↗
PubMedDate not supplied

[Assessment of various immunologic parameters in silicone implant carriers].

The Authors evaluated some immunological parameters in women carrying silicone gel-filled breast implants for over one year. Peripheral blood samples from 22 patients were examined in order to assess both the antigenic pattern of lymphocyte subpopulations by cytofluorimetric analysis, and the cell proliferation of PHA-stimulated lymphocytes by the uptake of tritiated thymidine. These tests were performed at the time of the sample withdrawal and after in vitro reexposure to silicone extract for 48-72h. Changes in lymphocyte subpopulations and functional response were observed when patients were divided into groups according to the type of surgery, i.e. breast augmentation or reconstruction, or to the degree of periprosthetic capsular contracture. These results suggest the possibility of an interaction between silicone and the immune system, which cannot be disregarded for the explanation of the silicone related complications.

Adult↗
PubMedDate not supplied

Evaluation of several immunological parameters in patients with aseptic loosening of hip arthroplasty.

The authors evaluated several immunological parameters in patients with loosened hip arthroplasty in order to determine the state of sensitization with regard to the metallic constituents of the prosthesis. The results obtained by in vivo epicutaneous testing did not reveal a correlation between loosening and sensitization, as the patch test was positive in only 1 out of 16 cases examined. An evaluation of the lymphocyte subpopulation on peripheral blood demonstrated that patients with prostheses in Cr, Co, Mo, Ni alloy present significant lymphopenia, with a reduction in subpopulations CD4 and CD8 and a decrease in in vitro cytotoxic activity. The meaning of these modifications could be interpreted to be either a toxic effect products released from the implant, or as the recruitment of lymphocytes in the site of loosening, due to lymphocyte sequestration phenomena consequent to a cell-mediated hypersensitivity reaction.

Aged↗
PubMedDate not supplied

The effects of orthopaedic cements on osteoblastic cells cultured in vitro.

The authors have examined the response of osteoblastic cells in contact in vitro with different acrylic cements used in orthopaedic surgery. The solid and liquid components of the cements were mixed in sterile environments according to the instructions provided by the manufacturers, and placed in contact with the cells 1/2, 1, 4, 6 and 24 hours after triggering of polymerization. The experimental model, that tends to define the kinetics of the release of toxic substances from acrylic cements, allowed to verify 24 hours after polymerization that the three cements had lost their toxic effects, which instead had been present to varying degrees for the first 1-6 hours. Cytomorphological observations did not reveal cellular damage, which instead was very clear when functional tests were used.

Acrylic Resins↗