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Biomedical subjects

D Granchi

Publications and source records attributed to D Granchi.

At least 73 records · Page 4Linked to original sources
PubMed1995

Silicone breast implants: the role of immune system on capsular contracture formation.

We evaluated the role of the immune system in the pathogenesis of the periprosthetic capsular contracture, the most frequently occurring complication following the implant of silicone prostheses. Peripheral blood samples from 22 patients with silicone-gel-filled implants were examined. In all cases a capsule was felt by palpation, and it was classified according to the Baker scale. Ten patients (group 1) had a Baker 2 contracture, and 12 (group 2) had severe contracture rated 3 and 4. The cells positive to antigens CD3, CD4, CD8, HLA-DR, CD19, CD25, CD57, CD16, and CD14, and the cytotoxic activity of the lymphocytes on target cells K562 were assessed by cytofluorimetric analysis. At time 0 there were no statistically significant differences between patients and normal subjects, nor between the two groups. At 48 h, the group 2 patients had a number/mm3 of cells CD57 + significantly higher than both group 1 and control group (P < .05). In group 1 patients, the cytotoxic activity was similar to that of normal subjects, whereas in group 2 it was significantly increased, in respect to both the controls (P < .05) and group 1 (P < .001). In all groups, the contact of the lymphocytes with the silicone extract did not modify either the antigen expression or the lymphocyte functional activity. On the basis of these results we hypothesize the involvement of the immune system in the formation of the capsular contracture around the prosthesis.

Adult↗
PubMed1995

Assessment of viability and proliferation of in vivo silicone-primed lymphocytes after in vitro re-exposure to silicone.

The functional response of peripheral blood lymphocytes isolated from 22 patients with silicone gel-filled breast implants was assessed after in vitro re-exposure to silicone. Using cell culture test methods to quantify proliferation and viability and/or activation of lymphocyte microcultures, i.e., the uptake of tritiated thymidine (3H-TdR uptake test) and the reduction of formazan salts (MTT assay), interesting data were obtained. Peripheral blood lymphocytes purified from patients wearing silicone gel-filled breast implants react in vitro to silicone showing a statistically significant increase of both proliferation and viability, while healthy subjects do not respond on in vitro exposure to silicone. Differences resulted even more statistically significant when patients were divided into two groups depending on the type of surgery they underwent: patients with breast augmentation for aesthetic reasons seem to have an increased responsiveness in vitro to silicone compared to patients who experienced a reconstructive surgery of the breast. Although they are still preliminary, being referred to a limited population, these results suggest that the lymphocytes of patients with silicone gel-filled breast implants could be sensitized in vivo toward silicone; the re-exposure of these cells to silicone leads to a higher functional response which could be looked for by using quantitative in vitro test methods.

Adult↗
PubMed1995

In vitro effects of bone cements on the cell cycle of osteoblast-like cells.

The effects of orthopaedic cements on the proliferation and cell cycle of in vitro cultured MG63 osteoblast-like cells were examined. Five different cements were mixed and extracted at different time intervals (15 and 60 min, 6, 24 and 48 h). Cell proliferation inhibition (CPI) was evaluated after 72 h culture as the toxicity parameter. As for the toxicity degree, the extracts were considered to have 'high toxicity' (CPI > or = 50%), 'medium toxicity' (50% > CPI > 25%), 'low toxicity' (CPI < or = 25%) and 'no toxicity' (CPI = 0). Cell cycle phases of MG63 cells were evaluated at 24, 48 and 72 h by flow cytometry; the DNA content was assessed using the propidium iodide uptake and the percentage of cells in the S phase was determined using 5'-bromodeoxyuridine uptake. According to our results, the toxicity is inversely correlated with the time interval between polymerization and extract preparation, and is different according to the cement type. For some cements the effects are still observed 48 h after polymerization. The damaging effect is not linked to a specific phase of the cell cycle, nor does it hamper the restarting of cell proliferation at 72 h.

Bone Cements↗
PubMed1995

Platelet and coagulation factor variations induced in vitro by polyethylene terephthalate (Dacron) coated with pyrolytic carbon.

The haemocompatibility of polyethylene terephthalate (Dacron) coated with pyrolytic carbon was examined in vitro, evaluating its capability of inducing adhesion and platelet activation, and of modifying the intrinsic coagulation pathway. Platelet adhesion was evaluated by counting platelets before and after in vitro contact of human plasma with the material under examination. Platelet activation was evaluated by determining platelet factor 4 (PF4) and thromboxane B2. Intrinsic coagulation pathway alterations were studied by determining activated partial thromboplastin time (APTT) and the activity of single factors. The results obtained show that pyrolytic carbon-coated Dacron induces platelet adhesion, reduction in platelet volume and lower increase in thromboxane production than that obtained after contact with uncoated Dacron. Pyrolytic carbon-coated Dacron does not induce PF4 release, contrary to uncoated Dacron induces a significant release. Moreover, pyrolytic carbon-coated Dacron, induces a significant extension of APTT by reducing the activity of intrinsic pathway factors, particularly factor XI.

Biocompatible Materials↗
PubMed1995

Adhesive protein expression on endothelial cells after contact in vitro with polyethylene terephthalate coated with pyrolytic carbon.

This research aims at evaluating the expression of some adhesive proteins on endothelial cell surface with polyethylene terephthalate coated with pyrolytic carbon (PET + PC). Twenty-two different cultures of human umbilical vein endothelial cells (HUVECs) were put in contact with PET + PC. Both HUVECs grown without the biomaterial and HUVECs incubated with endotoxin were used as control. After 24 h, platelet endothelial cell adhesion molecule-1 (PECAM-1), endothelial leukocyte adhesion molecule-1 (ELAM-1), intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were evaluated on the cells by monoclonal antibodies and flow cytometry. In agreement with the literature, after 24 h the culture incubated with endotoxin determined a significant increase in the percentage of positive cells for ELAM-1, a significant increase in fluorescence intensity of ICAM-1, and a significant increase in the percentage of positive cells and fluorescence intensity for VCAM-1. After 24 h of culture with PET + PC, no significant variations in the antigens examined were observed. This demonstrates that such material does not activate in vitro the proteins involved in the adhesion between leucocytes and endothelium or in the adhesion between endothelial cells themselves.

Antigens, Differentiation, Myelomonocytic↗
PubMed1995

Endodontic cements induce alterations in the cell cycle of in vitro cultured osteoblasts.

The effects of endodontic cements on the cell cycle of MG63 osteoblasts cultured in vitro have been examined. Three groups of compounds were tested. Group I encompassed zinc oxide- and eugenol-based cements (Tubliseal, Argoseal, N2), group II consisted of cements with a phenol group other than eugenol (AH26, Forfenan, Methode R/R), and group III included CaOH-based cements (Biocalex, Endocalex). The cell cycle of MG63 cells was analyzed by flow cytometry; the DNA content was evaluated by means of the propidium iodide uptake method, whereas the proportion of cells in the S phase was defined by the incorporation of bromodeoxyuridine later revealed by a specific antibody. The results showed that some root canal sealers could hamper the periapex healing processes by inhibiting the cell proliferation through a selective action on different phases of the cell cycle.

Analysis of Variance↗
PubMed1995

[Evaluation of the biocompatibility of medical devices based on European standards].

Several issues concerning the biocompatibility) testing of medical devices as stated in European directive 90/385 and 93/42 are discussed. The authors describe the fundamental characteristics that biomaterials should have to be employed in the human body, the assays useful for testing different aspects of biocompatibility and the harmonized regulations already available or under development. The testing protocol applied by the a. in their Lab covering many issues of biocompatibility is presented: a body of experience was gained over the years and it has been revised under the new regulatory items. In conclusion, the biocompatibility of devices must be assessed following the European harmonized standards, the available. Where proper standards are still lacking, feasible testing methods, even if not officially adopted yet, have to be used.

Biocompatible Materials↗
PubMed1995

[European regulations concerning medical devices].

The employment in clinical practice and prosthetic surgery of a number of medical devices implies a great responsibility to the operators so as to make the knowledge of existing regulations mandatory. The authors illustrate the problems concerning the free circulation of medical devices within the European market. They describe the new strategy of EEC which led to the definition of the directives which apply to all medical devices and of the harmonized standards for inspecting their biological effects. The appointment of certification bodies and the accreditation of Testing Laboratories are described. Finally, particular attention is given to product certification, which is compulsory for the pre-market approval of medical devices.

Accreditation↗
PubMed1994

Plasma zinc level and thymic hormone activity in young cancer patients.

It has been reported that in many neoplastic diseases, including leukemia, alterations in plasma zinc levels may frequently occur, although the causes for such alterations have yet to be clearly defined. Since zinc is required to induce biological activity to thymulin (Zn-FTS), a biochemical defined thymic hormone, and marginal zinc deficiencies may prevent its peripheral biological activation, we investigated the plasma level of zinc and of both active thymulin (Zn-FTS) and total zinc saturable thymulin (Zn-FTS + FTS) in 91 young patients affected by acute lymphoblastic leukemia (ALL) at various stages of the disease. It was discovered that the plasma zinc level was reduced at the onset and relapse, whereas in complete remission and in off-therapy it was in the normal range. Total zinc-saturable thymulin concentration did not change during the disease, whereas the active fraction was reduced at the onset and in relapse when compared with values observed in the other stages of the disease or in healthy controls. These data suggest that zinc plasma deficiency is present in ALL patients at the onset and during relapse, and that such a deficiency causes a decrease in the activity of thymulin despite a nearly normal production by the thymus. An impairment of peripheral immune efficiency in ALL patients is commonly found. The existence of positive correlations between zinc or active thymulin and peripheral immunological parameters (phytohemagglutinin [PHA] and concanavalin A [ConA]) at various stages of the disease suggests a link between derangement of peripheral immune function, thymic hormone activity, and zinc failure. These findings, considered together, suggest the possibility of a carefully controlled clinic trial with zinc in ALL patients at the onset and in relapse even in the light of in vitro ineffectiveness of physiological zinc or thymulin concentrations on the duplicative index of human lymphoblastoid cells.

Adolescent↗
PubMed1994

Cell culture methods for testing biocompatibility.

Cell culture systems may be of value in testing the biocompatibility of prosthetic materials before they are introduced into clinical use. In recent years, in vitro methods for assaying biomaterials have gained in importance owing to the growing concern over the use of animals for biomaterials testing. Significant effort is therefore being focused toward developing predictive and quantitative, but also simple and reliable, methods of testing using cultured cells. At present, a number of methods for measuring both the cytotoxicity and the specific cytocompatibility of different materials are available. The usefulness of these systems is no longer confined to screening new materials; they can be used to study the mechanisms of action of various materials during tissue/material interaction. This paper reviews the published literature on the use of cell culture models in evaluating biocompatibility and reports on the personal experience of the authors, who have been using cell culture systems for many years and for different purposes.

Biocompatible Materials↗
PubMed1993

[Assessment of the plasma phase of coagulation in platelet-rich plasma after passage through a special polyester filter].

The authors have examined the alterations in the coagulation pathway of plasma filtered through a polyester filter coated by a hydrophilic polymer. The activation of the coagulation pathway was evaluated by measuring prothrombin time, activated partial thromboplastin time, coagulation factors and fibrinopeptide A. The results obtained demonstrate that the examined filter does not induce significative activation of the coagulation pathway.

Blood Coagulation↗
PubMed1991

Co-expression of myeloid antigens in childhood acute lymphoblastic leukaemia: relationship with the stage of differentiation and clinical significance.

Co-expression of myeloid antigens on the leukaemic blast cells was evaluated in 532 children with a diagnosis of acute lymphoblastic leukaemia (ALL). Using a panel of monoclonal antibodies belonging to CD11b, CD13, CD14, CD15 and CD33 an overall incidence of 4.3% was found, with values ranging between 1.8% for CD14 and 6.1% for CD15. When the data were further dissected, a significantly higher incidence of co-expression was noted in null-ALL (15/70 cases = 21.4%), compared to cases expressing a more mature immunophenotype, i.e. common-ALL (7/394 cases = 1.7%) and T-ALL (1/68 cases = 1.4%) (P less than 0.001). In null-ALL, 9/15 patients were infants, five of whom with the t(4;11); two further children also had a t(4;11). The clinical outcome of the 23 cases which co-expressed myeloid antigens was unfavourable. Only two of the 15 null-ALL, two of the seven common-ALL and the unique case with T-ALL are in fact in persistent first remission between 19 and 93 months from diagnosis. Though the overall incidence of childhood ALL expressing myeloid antigens is low, the evidence that this co-expression may be related to an unfavourable clinical course and that it more frequently occurs in null-ALL, particularly in the first year of life, suggests that the routine assessment of myeloid antigens may allow to identify a subgroup of childhood ALL with a poor clinical outcome.

Adolescent↗
PubMed1990

Establishment and characterization of a primitive neuroectodermal tumor of bone continuous cell line (LAP-35).

A continuous tumor cell line (LAP-35) was established from a primitive neuroectodermal tumor of bone from the right tibia of a 12-year-old female. The neural character of the cell line was documented by the spontaneous growth of neurites and by the presence of several neural markers, including neuron-specific enolase (NSE), S-100 protein, neurofilaments, chromogranin A, synaptophysin and positivity to monoclonal antibodies UJ127.11, UJ13A, UJ181.4. Cell-sorter analysis showed a high expression of nerve growth factor receptor (NGFr) and major histocompatibility complex class I-related molecules. A unique cytogenetic profile was observed, including a reciprocal chromosomal translocation (rct) 11:22 (q24;q12), typically associated with Ewing's sarcoma and neuroepithelioma, and deletion of the short arm of chromosome 1 (lp-), otherwise a feature of neuroblastoma. N-myc proto-oncogene was neither amplified nor expressed, whereas the expression of c-myc was documented by northern blot analysis. These features distinguish this new cell line from previously reported neuroectodermal cell lines, identifying LAP-35 as a unique model of a group of neural bone tumors that share characteristics of neuroblastoma as well as neuroepithelioma.

Animals↗
PubMedDate not supplied

Effects of chromium extract on cytokine release by mononuclear cells.

We have evaluated the effects of chromium extract on the release by peripheral blood mononuclear cells (PBMCs) of cytokines favouring bone resorption. Furthermore, we have evaluated whether the chromium effects could be correlated with the activation and proliferation of PBMCs. Cell cultures were maintained in serum-free medium (AIM-V), in order to avoid the interference of exogenous growth factors. Increasing concentrations of chromium extract, ranging between 3 and 100%, were added to culture medium. Cytokine release (IL-1beta, TNFalpha, IL-6, GM-CSF and IFNgamma) was assessed on both PBMCs cultured with AIM-V only (unstimulated PBMC) and PBMCs cultured with AIM-V plus phytohaemagglutinina (PHA-stimulated PBMC). The activation and proliferation of PBMCs were evaluated by assessing DNA synthesis and soluble IL-2 receptor release, in order to determine whether an IL-2-dependent immune response can be induced by chromium. Our results show that in unstimulated PBMCs chromium ions slightly increased the release of pro-inflammatory cytokines, such as TNFalpha and IL-6, even though the increase is not significant. On the contrary, the different concentrations of chromium extract significantly inhibited the response to PHA stimulation, as shown by the decrease in IL-6 and sIL-2r release, and by the influence on cell viability and DNA synthesis. Both these effects are undesirable and support hypotheses on the biological effects of chromium. The continuous release of chromium from the implant could induce in PBMCs the release of bone-resorbing cytokines, which in the long term could be responsible for irreversible tissue damage. Moreover, chromium seems to inhibit the IL-2-dependent response of PBMCs, so that they are not able to trigger an efficient cell-mediated immune response.

Bone Resorption↗
PubMedDate not supplied

Adhesive protein expression on human endothelial cells after in vitro contact with woven Dacron.

In this research adhesive proteins are studied in order to evaluate the interference of woven Dacron in the endothelialization process and in the ability of endothelial cells to bind circulating leucocytes. Endothelial cells from human umbilical vein (HUVEC) were put in contact with woven Dacron for 24 h. PECAM-1, ELAM-1, ICAM-1 and VCAM-1 expression was then evaluated by flow cytometry, using indirect immunofluorescence reaction with monoclonal antibodies. The study of adhesive proteins was completed with the quantitative determination of surface antigens expressed as the antibody binding capacity (ABC). Antigenic density was calculated by the DAKO QFIT calibration system for indirect immunofluorescence. After contact with woven Dacron no significant change was observed in the percentage of positive cells or in the fluorescence intensity of the adhesins. No significant variation was also noted by calculating the surface antigen density by means of calibration fluorospheres. It can be concluded that the material examined does not significantly affect leucocyte adhesion to the endothelium.

Biocompatible Materials↗
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↗