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Biomedical subjects

P Torricelli

Publications and source records attributed to P Torricelli.

At least 55 records · Page 3Linked to original sources
PubMed2001

Calcitonin release system in the treatment of experimental osteoporosis. Histomorphometric evaluation.

Bioabsorbable polyphosphazene matrices charged with 250 microg calcitonin were evaluated as calcitonin delivery systems for the controlled release of this drug in an in vivo experimental model. Matrices were implanted under general anesthesia in osteopenic female rats, while a group of osteopenic animals (control group) received unloaded matrices. After 30 days a second series of matrices, loaded and unloaded was, respectively, implanted in both groups. In a third group of osteopenic female rats (positive control), 10 IU calcitonin were injected daily for two months. A baseline group and a sham operated group of animals were also included in the study. The explanted matrices were histologically evaluated together with the surrounding tissues, and bone histomorphometry was performed on undecalcified sections from femurs. The results showed the good biocompatibility of the matrices. Bone histomorphometry revealed that bone architecture in the treatment group was improved and results were not different from those observed after calcitonin injection. These data confirm a good in vivo behavior of the system, as well as a therapeutic effect of the released calcitonin in the osteopenic condition.

Animals↗
PubMed2001

Laser biostimulation of cartilage: in vitro evaluation.

An in vitro study was performed to evaluate the laser biostimulation effect on cartilage using a new gallium-aluminium-arsenic diode laser. Chondrocyte cultures were derived from rabbit and human cartilage. These cells were exposed to laser treatment for 5 days, using the following parameters: 300 joules, 1 watt, 100 (treatment A) or 300 (treatment B) hertz, pulsating emission for 10 minutes, under a sterile laminar flow. Control cultures (no treatment) received the same treatment with the laser device off. Cell viability was measured by MTT assay at the end of the laser treatment and then after 5 days. Neither rabbit nor human cultured chondrocytes showed any damage under a light microscope and immunostaining control following laser treatment. The MTT test results indicated a positive biostimulation effect on cell proliferation with respect to the control group. The increase in viability of irradiated chondrocytes was maintained for five days following the end of the laser treatment. The results obtained with the Ga-Al-As diode laser using the above tested parameters for in vitro biostimulation of cartilage tissues provide a basis for a rational approach to the experimental and clinical use of this device.

Analysis of Variance↗
PubMed2001

Effect of L-lysine and L-arginine on primary osteoblast cultures from normal and osteopenic rats.

A therapeutic role of amino acids L-lysine (Lys) and L-arginine (Arg) in osteoporosis and fracture healing was demonstrated previously by in vivo studies. In the present study, primary cultures of osteoblasts were used to investigate the effect of amino acids on gene expression (alkaline phosphatase activity, ALP; osteocalcin, OC; type I collagen), nitric oxide production (NO) and proliferation (MTT) of cells. Cells were isolated from the distal femurs of normal and osteopenic rats. Normal and osteopenic bone-derived cells were divided into four groups: control, Lys (0.587 mg/mL/d), Arg (0.625 mg/mL/d), and Lys + Arg (0.587 + 0.625 mg/mL/d). No evidence of differences between normal and osteopenic bone-derived cultures in basal conditions was observed. A significant (P = 0.002) increase of 10.4% in NO production was observed in normal bone-derived osteoblasts treated with Lys + Arg when compared to the control group at 7 days. At the same time, normal bone-derived osteoblasts treated with Arg and Lys + Arg showed significant increases in type I collagen synthesis of 25.3% and 28.4%, respectively, when compared to the control group. Osteopenic bone-derived osteoblasts showed significant (P = 0.002) increases of 27.6% in MTT and 28.7% in cell count at 48 hours when treated with Lys + Arg in comparison with the control group. At 7 days, NO production and type I collagen synthesis increased significantly (P< 0.005) both in osteopenic bone-derived osteoblasts treated with Arg (NO: 18.5%; type I collagen: 34.4%) and Lys + Arg (NO: 23.7%; type I collagen: 20.9%) compared to the control group. Finally, a significant (P = 0.025) decrease of 5.8% in OC level was observed in osteopenic bone-derived osteoblasts treated with Arg. Results suggest that the potential therapeutic effect of Lys and Arg on bone could be related, at least in part, to an improvement of NO production and type I collagen synthesis by osteoblasts both in normal and in osteopenic bone. In osteopenic bone-derived osteoblasts this synthetic phase is preceded by an initial increase of cell proliferation.

Animals↗
PubMed2001

Pericellular partial oxygen pressure (pO2) measurement in osteopenic bone-derived osteoblast cultures.

In order to achieve further information on the in vitro behaviour of osteoblasts derived from osteopenic bone, in the present study comparative measurements of some parameters of cell proliferation, metabolism and differentiation and also of the pericellular partial oxygen pressure (pO2) were performed on normal and osteopenic bone derived osteoblasts from heathy and osteopenic rats. The respiration rate was increased in osteoblasts derived from osteopenic bone as compared to normal cells at 48 hours and 7 days, involving a significant decrease in pericellular pO2 in the culture medium. At 48 hours, in osteopenic bone-derived cells, a significant increase in MTT and a significant decrease of osteocalcin were observed. At 7 days, cell count highlighted a significant slowing down of the proliferation of osteopenic bone-derived osteoblasts. No significant differences were observed for alkaline phosphatase activity, nitric oxide and type I collagen production. The present preliminary results may be taken into consideration also in in vitro comparative biocompatibility or osteointegration studies of biomaterials in normal and osteopenic bone-derived cells because a decrease in pericellular pO2 in these tissue cultures could influence results on material behaviour.

Animals↗
PubMed2001

Low-power diode laser stimulation of surgical osteochondral defects: results after 24 weeks.

The purpose of this study was to evaluate osteochondral lesions of the knee, treated intraoperatively with low-power laser stimulation, and assess results at 24 weeks. Surgery was performed under general anesthesia on six rabbits; a bilateral osteochondral lesion was created in the femoral medial condyles with a drill. All of the left lesions underwent immediate stimulation using the diode Ga-Al-As laser (780nm), whereas the right knees were left untreated as control group. After 24 weeks, the explants from the femoral condyles, either treated employing laser energy or left untreated, were examined histomorphometrically. Results obtained on the lased condyles showed good cell morphology and a regular aspect of the repaired osteocartilaginous tissue.

Animals↗
PubMed2001

Bone tissue cultures: an in vitro model for the evaluation of bone defect healing after L-arginine and L-lysine administration.

The development of new therapeutic strategies and innovative biomaterials for the muscoloskeletal system, stresses the need for researchers to have reliable, easy, less time-consuming and ethical experimental models. The aim of the present study was to characterise an in vitro model of cultured rat femora and test the possibility of using this model in dynamic studies on bone healing. 24 femurs were explanted after 12 rats were killed for other experimental protocols. A standard bone defect was created in the distal femoral condyles and femurs were cultured in GBJb medium. Arginine and lysine were administered daily in the Arg-Lys group. The other femurs were left untreated (Control group). At 1, 7, 14 and 21 days, alkaline phosphatase activity, nitric oxide and calcium were measured on the supernatant. At 21 days, femurs were embedded in polymethylmethacrylate for histomorphometry and microhardness evaluation of the newly formed bone. The current results showed that it was possible to study bone healing in vitro by using cultured bones from adult animals. A process for bone healing was observed also in untreated bones. Moreover, the structural analysis of the cultured bone showed that it had characteristics similar to those of the femurs, when they were embedded in resin immediately after animal sacrifice. The effect of Arg and Lys confirmed data of a previous study, where a faster healing of bone defect and fracture was observed in rabbits after Arg and Lys administration.

Alkaline Phosphatase↗
PubMed2001

Biocompatibility and osseointegration in osteoporotic bone.

We implanted nails made of titanium (Ti6Al4V) and of two types of glass ceramic material (RKKP and AP40) into healthy and osteopenic rats. After two months, a histomorphometric analysis was performed and the affinity index calculated. In addition, osteoblasts from normal and osteopenic bone were cultured and the biomaterials were evaluated in vitro. In normal bone the rate of osseointegration was similar for all materials tested (p < 0.5) while in osteopenic bone AP40 did not osseointegrate (p < 0.0005). In vitro, no differences were observed for all biomaterials when cultured in normal bone-derived cells whereas in osteopenic-bone-derived cells there was a significant difference in some of the tested parameters when using AP40. Our findings suggest that osteopenic models may be used in vivo in the preclinical evaluation of orthopaedic biomaterials. We suggest that primary cell cultures from pathological models could be used as an experimental model in vitro.

Alloys↗
PubMed2001

Dynamic contrast enhanced magnetic resonance imaging subtraction in evaluating osteosarcoma response to chemotherapy.

PURPOSE: To evaluate the results of a new technique of dynamic contrast enhanced Magnetic Resonance (MR) imaging subtraction in the assessment of osteosarcoma response to chemotherapy. METHODS: 24 patients with high grade osteosarcoma, treated with preoperative neo-adjuvant chemotherapy, underwent MR at high field strength (1.5 T). Both unenhanced conventional SE T1- and T2-weighted sequences in the coronal and axial plane and dynamic Gd-DTPA-enhanced SE T1-weighted sequences in the coronal plane were performed. Image postprocessing included subtraction of unenhanced image from enhanced images (arbitrary called "angiographic subtraction") and subtraction of each enhanced image from the last-enhanced image (arbitrary called "pathologic area" subtraction). The early enhancing areas detected in the angiographic subtraction and the pathologic areas detected in the pathologic area subtraction were correlated with histopathological findings on histological macrosections obtained from the resected specimen. The sensitivity, specificity, accuracy, positive and negative predictive value of both the subtraction techniques were calculated. RESULTS: The early enhancing areas of angiographic subtraction were related not only to viable tumor but also to the host reactions such as flogosis and granulation tissue. The pathologic areas detected at the pathologic area subtraction correlated in most cases with viable tumor, while in 3 cases they did not correspond to viable tumor tissue and in 1 case a small area of residual viable tumor was missed. In assessing response to chemotherapy, pathologic areas subtraction had an accuracy of 95% (specificity: 100%, sensitivity: 93%, PPV: 100%, NPV: 88%), whereas angiographic subtraction had an accuracy of 79% (specificity: 37%, sensitivity: 100%, PPV: 76%, NPV: 100%). CONCLUSIONS: Pathologic area subtraction may be a useful technique for assessing the response of osteosarcoma to chemotherapy and for detecting residual viable tumor tissue.

Adolescent↗
PubMed2001

The ovariectomized ewe model in the evaluation of biomaterials for prosthetic devices in spinal fixation.

The effect of surgical ovariectomy on cancellous bone was investigated by comparing mechanical properties and microarchitectural characteristics of the lumbar vertebrae in ovariectomized and sham-operated ewes. Eighteen mongrel ewes, 4+/-1 years old, were randomly divided into three groups: 6 animals served as a control group (Baseline), 6 were bilaterally ovariectomized (OVX), and the others were used as a sham-operated group (SHAM). OVX and SHAM ewes were euthanized 24 months after surgery; the L5 vertebrae were processed for mechanical and histomorphometric analyses. Maximum load, maximum strength (p<0.0005) and elastic modulus (p <0.005) decreased by about 28% in the OVX group in comparison with the other groups. In the OVX group, vertebral cancellous bone volume, trabecular thickness and trabecular number decreased by about 32% (p<0.0005), 15% (p=0.001) and 20% (p=0.019), respectively. An overall decrease in the bone turnover rate of the OVX group was registered in terms of bone formation rate (p=0.007) and activation frequency (p<0.0005). The variations observed in cancellous bone mechanics and histomorphometry would suggest the development of an osteopenic state in ewe vertebrae at 24 months. Such findings may be useful for future experimental investigations on biomaterials and prosthetic devices to be implanted in the osteopenic spine.

Animals↗
PubMed2001

Laser technology in orthopedics: preliminary study on low power laser therapy to improve the bone-biomaterial interface.

Low Power Laser (LPL) seems to enhance the healing of bone defects and fractures. The effect of LPL in other orthopedic areas such as osteointegration of implanted prosthetic bone devices is still unclear. In the present study, 12 rabbits were used to evaluate whether Ga-Al-As (780 nm) LPL stimulation has positive effects on osteointegration. Hydroxyapatite (HA) cylindrical nails were drilled into both distal femurs of rabbits. From postoperative day 1 and for 5 consecutive days, the left femura of all rabbits were given LPL treatment (Laser Group-LG) with the following parameters: 300 Joule/cm2, 1 Watt, 300 Hertz, pulsating emission, 10 minutes. The right femura were sham-treated (Control Group-CG). At 4 and 8 weeks after implantation, histologic and histomorphometric investigations evaluated bone-biomaterial-contact. Histomorphometry showed a higher degree of osteointegration at the HA-bone interface in the LG Group at 4 (p < 0.0005) and 8 weeks (p < 0.001). These preliminary positive results seem to support the hypothesis that LPL treatment can be considered a good tool to enhance the bone-implant interface in orthopedic surgery.

Animals↗
PubMed2000

Isolation and characterization of osteoblast cultures from normal and osteopenic sheep for biomaterials evaluation.

Being very useful in the analysis of bone cell differentiation and activity, osteoblast cultures are also used in the in vitro biocompatibility study of new materials. The aim of this work was to evaluate sheep osteoblast cultures derived from normal and ovariectomized animals, and then to assess the in vitro biomaterial behavior on these cultures, taking into account the quality of bone where orthopedic devices are clinically used. For this purpose, we characterized sheep osteoblast cultures, isolated from iliac crest bone of normal (NB osteoblast culture) and osteopenic after ovariectomy (OB osteoblast culture) sheep. Moreover, we studied cell behavior when cultured on different biomaterials (titanium and two biological glasses, RKKP and AP40). Cell characterization at baseline demonstrated that both cultures (NB and OB) showed normal osteoblastic behavior. On the contrary, osteoblasts derived from osteopenic bone and cultivated on AP40 for 6 days revealed a different behavior in terms of both cell morphology and metabolic activity. Statistical analysis (one-way analysis of variance and Scheffé's post hoc multiple-comparison tests) revealed significant differences in Ca level (p<0.0005), MTT test (p<0.0005) and OC production (p<0.05). These in vitro tests demonstrated that sheep osteoblast cultures can be useful when determining biocompatibility and osteointegration of orthopedic materials, and also when evaluating for the presence of osteoporosis.

Animals↗
PubMed2000

The effect of osteopenia on the osteointegration of different biomaterials: histomorphometric study in rats.

The osteointegration of Hydroxyapatite (HA), Titanium (Ti-6Al-4V: Ti), Zirconia (ZrO2), Alumina (Al2O3) and 2 biological glasses (AP40 and RKKP) was comparatively investigated in normal and osteopenic rats by means of histomorphometry. Thirty-six Sprague Dawley female rats were left intact (Group C) while 36 were ovariectomized (Group OVX). Group C and OVX were further divided into 6 subgroups. After 16 weeks all animals were submitted to the femoral implant of nails made of the above-mentioned materials. Eight weeks after implantation the animals were euthanized, the femurs were harvested for histomorphometric analysis. The data showed that: (1) all the tested materials were biocompatible in vitro; (2) no significant differences existed in Affinity Index (AI) of Group C; and (3) results from paired comparison applied to the AI showed significant differences among the Groups C and OVX. The AI did not significantly change among intact groups, while it significantly decreased when some materials were implanted in OVX subgroups (AP40, ZrO2 and Ti-6Al-4V: p < 0.0005, p < 0.05 and p < 0.01). It is confirmed that bone mineral density is a strong predictor of the osteointegration of an orthopedic implant and that the use of pathological animal models is necessary to completely characterize biomaterials.

Journal Article↗
PubMed2000

In vitro pathological model of osteopenia to test orthopaedic biomaterials.

The association of in vitro tests and in vivo bone implants, has significantly improved the characterization of biomaterials for orthopaedic devices before their clinical use. However, neither cell cultures nor most animals models used for these tests entirely reflect the clinical conditions in which biomaterials are implanted. Pathological animal models are considered to substantially improve our knowledge of osteointegration of biomaterials; for this reason researchers increasingly use aged, osteopenic or arthritic animals in their experimental tests. The development of "pathological cell cultures" would also be of great importance for the study of biomaterials. It would allow a complete material evaluation, beginning with a biocompatibility test to a more finalized and specific preclinical evaluation. The present study, looks at the possibility of using cell culture methodology for the improvement of in vitro biomaterials characterization in the case of osteopenia. Cultures derived from normal (NB-OST) rats were compared to those of osteopenic (OB-OST) rats, by testing the osteoblasts against common parameters of characterization. Moreover, the reaction of these cultures to two biological glasses of known in vivo behavior (both in normal and osteopenic bone) by means of parameters on biocompatibility and bone formation index, was evaluated. Our results showed that there was no evidence of differences between the NB-OST and OB-OST cultures. After 6 days of culturing, the bioglass that did not osteointegrate in osteopenic animals, did not induce cytotoxicity in NB-OST, but a significative reduction of viability and Osteocalcin level in OB-OST was observed. We think that these data should stimulate researchers to develop further tests in order to improve preliminary in vitro comprehension on biomaterials.

Alkaline Phosphatase↗
PubMed2000

Biostimulation of human chondrocytes with Ga-Al-As diode laser: 'in vitro' research.

The aim of this study was to verify the effects of laser therapy performed with Ga-Al-As Diode Lasers (780 nm, 2500 mW) on human cartilage cells in vitro. The cartilage sample used for the biostimulation treatment was taken from the right knee of a 19-year-old patient. After the chondrocytes were isolated and suspended for cultivation, the cultures were incubated for 10 days. The cultures were divided into four groups. Groups I, II, III were subject to biostimulation with the following laser parameters: 300 J, 1 W, 100 Hz, 10 min. exposure, pulsating emission; 300 J, 1 W, 300 Hz, 10 min. exposure, pulsating emission; and 300 J, 1 W, 500 Hz, 10 min. exposure, pulsating emission, respectively. Group IV did not receive any treatment. The laser biostimulation was conducted for five consecutive days. At the end of the treatment, the Calcium, Alkaline Phosphate, MTT tests and proteoglycan were performed to assess cell metabolism and toxicity level. The data showed good results in terms of cell viability and levels of Ca and Alkaline Phosphate in the groups treated with laser biostimulation compared to the untreated group. The results obtained confirm our previous positive in vitro results that the Ga-Al-As Laser provides biostimulation without cell damage.

Adult↗
PubMed2000

Assessment of low-power laser biostimulation on chondral lesions: an "in vivo" experimental study.

The purpose of this study was to evaluate whether intraoperative laser biostimulation can enhance healing of cartilaginous lesions of the knee. Surgery was performed on eighteen rabbits: a bilateral chondral lesion of 1.25 +/- 0.2 mm in length and 0.8 +/- 0.2 mm in width was created in the femoral medial condyle with a scalpel. The lesion in the left knee of each animal was treated intraoperatively using the diode Ga-Al-As 780nm. laser (300 Joules/cm2, 1 Watt, 300 Hertz, 10 minutes), while the right knee was left untreated, as control group. The animals were divided into three groups, A, B and C, according to the survival time after surgery, two, six and twelve weeks, respectively. The explants from the femoral condyles, both treated employing laser energy and left untreated, were examined histologically. Results showed a progressive filling with fibrous tissue of the cartilaginous lesion treated with laser irradiation, while no changes in the original lesion of the untreated group were observed at the end of the study. Maybe, in this experimental research, underexposure to laser irradiation was the cause for the absence of the necessary conditions for biostimulation.

Animals↗
PubMed2000

Osteochondral lesion repair of the knee in the rabbit after low-power diode Ga-Al-As laser biostimulation: an experimental study.

The purpose of this study was to evaluate whether low-power laser biostimulation of the osteo-chondral lesions of the knee could by itself reduce repair healing time. Surgery was performed on eighteen rabbits; a bilateral osteo-chondral lesion of 2.5mm in diameter and 2mm depth was created in the femoral medial condyle with a drill. The left knee of each animal was treated intraoperatively using the diode Ga-Al-As laser (780nm) with the following parameters: 300 Joules/cm2, 1 Watts, 300 Hertz, 10 minutes; the right knee was left untreated, as control group. The animals were divided into three groups, A, B and C, according to the survival time after surgery, two, six and twelve weeks, respectively. The explants from the femoral condyles, either treated employing laser energy or left untreated, were examined histomorphometrically. Results after laser treatment showed faster healing of the lesion at week 2 (p=0.043) and an overall improvement in cellular morphology (p=0.044), while a more regular aspect of the osteocartilaginous tissue was observed at week 12 (p=0.004). A relationship between laser biostimulation properties and healing of the osteo-chondral defect has been demonstrated.

Aluminum↗