Search PubMed⌕ Search

Biomedical subjects

F Bassi

Publications and source records attributed to F Bassi.

At least 19 recordsLinked to original sources
PubMed2006

Development of glass-ceramic scaffolds for bone tissue engineering: characterisation, proliferation of human osteoblasts and nodule formation.

Glass-ceramic macroporous scaffolds for tissue engineering have been developed using a polyurethane sponge template and bioactive glass powders. The starting glass (CEL2) belongs to the system SiO(2)-P(2)O(5)-CaO-MgO-Na(2)O-K(2)O and has been synthesised by a conventional melting-quenching route. A slurry of CEL2 powder, polyvinyl alcohol and water has been prepared in order to coat, by impregnation, the polymeric template. An optimised thermal treatment was then use to remove the sponge and to sinter the glass powders, leading to a glass-ceramic replica of the template. Morphological observations, image analyses, mechanical tests and in vitro tests showed that the obtained devices are good candidates as scaffolds for bone-tissue engineering, in terms of pore-size distribution, pore interconnection, surface roughness, and both bioactivity and biocompatibility. In particular, a human osteoblast cell line (MG-63) seeded onto the scaffold after a standardised preconditioning route in simulated body fluid showed a high degree of cell proliferation and a good ability to produce calcium nodules. The obtained results were enhanced by the addition of bone morphogenetic proteins after cell seeding.

Biocompatible Materials↗
PubMed2006

Internal adaptation of fixed prosthodontics at shoulder preparation level evaluated by horizontal sections.

AIM: The precision of fixed prosthodontic restorations is fundamental for clinical success: well-fitting crowns reduce the risk of recurrent caries and periodontal disease. The aim of this study is to evaluate the internal fit of fixed prosthodontics at the shoulder preparation level by examining horizontal sections. METHODS: Twenty-four extracted teeth were resin-embedded and prepared on the platform of an iso-parallelometer with a 90 degrees shoulder with a rounded internal angle. Auro Galva Crown (AGC) copings were cemented in place. The preparations were observed by 3 different assessors at 8 points, first externally and then internally at 2 levels by grinding the specimen perpendicular to the long axis at 0.5 mm and at 0.2 mm from the margin of the preparation. A correction factor was calculated to derive real values from measured values. The results were analyzed using a linear regression with robust standard errors, accounting for within-subject correlation introduced by multiple measurements. Shrout-Fleiss Intraclass Correlation Coefficient (ICC) for Inter-Rater Reliability were calculated at each stage. RESULTS: Internal measurements at 0.5 and 0.2 mm from the margin provided data similar to the external margin data. Average inter-assessor differences were in the range of 2 mm. ICC ranged from 0.93 for the 0.5 mm level to 0.97 for the external level. CONCLUSIONS: External measurements effectively predict the internal precision at the shoulder level. Horizontal perimarginal sections allow the fit to be studied through the evaluation of a great number of points. Traditional vertical sections for the evaluation of internal fit enable only a few points to be observed. This internal observation method may be suitable for testing new materials.

Humans↗
PubMed2005

Inhibition of phospholipase A2 activity reduces membrane fluidity in rat hippocampus.

Phospholipase A2 (PLA2) is a family of key enzymes in membrane phospholipid metabolism. In rats, the inhibition of PLA2 activity in the hippocampus was found to impair memory formation. Because memory function is largely dependent on the fluidity of brain membranes, we performed the present study to investigate the effects of in vivo PLA2 inhibition (with PACOCF3) on the fluidity of hippocampal membranes from rats trained in a learning task. Hippocampal tissue from rats injected with 100 microM PACOCF3 showed reduced membrane fluidity as compared to vehicle (p < 0.01), and the reduction of membrane fluidity was highly correlated with PLA2 inhibition (r = .76, p < 0.03). This finding is of interest because reduction of brain membrane fluidity impairs memory formation and both decreased PLA2 activity and reduced membrane fluidity have been reported in the brain from patients with Alzheimer's disease.

Animals↗
PubMed2003

Three-dimensional CT imaging and virtual endoscopy for the placement of self-expandable stents in oesophageal and tracheobronchial neoplastic stenoses.

We examined the value of multislice computed tomography (CT) with three-dimensional (3D) reconstruction of the images as a pre-treatment examination in order to plan endoluminal stenting in 14 patients with large tumours involving the oesophagus and/or the tracheobronchial tree. The measurement of the stenosis obtained during 3D reconstruction of the CT images corresponded to that obtained by endoscopy and to the prosthesis chosen in all cases, with the exception of one patient undergoing double stenting due to inadequate gaseous distension of the oesophageal lumen. 3D CT may add information with respect to axial imaging, and be helpful to better plan and perform stenting of the oesophagus and airways without burdening the preoperative work-up.

Aged↗
PubMed2001

The problem of the accuracy of intraoperative examination of axillary sentinel nodes in breast cancer.

BACKGROUND: Sentinel node (SN) biopsy has become accepted as a reliable method of predicting the state of the axilla in breast cancer. The key issue, however, is the accuracy of the pathological evaluation of the biopsied node, which should be done intraoperatively whenever possible. METHODS: In our initial experience on 192 patients using a conventional intraoperative frozen section method, the false-negative rate was 6.3%, and the negative predictive value was 93.7%. We devised a new and exhaustive intraoperative method, requiring about 40 minutes, in which pairs of sections are taken every 50 microm for the first 15 sections and every 100 microm thereafter, sampling the entire node. Sentinel node metastases were found in 143 of the 376 T1N0 cases examined (38%). RESULTS: Metastases were always identified on hematoxylin and eosin sections, although in 4% of cases, cytokeratin immunostaining on adjacent sections was useful for confirming malignancy. In 233 patients the SNs were disease-free; of these patients, 222 had metastasis-free axillary nodes, and 11 (4.7%) had another metastatic node. CONCLUSION: Extensive intraoperative examination of frozen sentinel nodes correctly predicts an uninvolved axilla in 95.3% of cases (negative predictive value). This method is, therefore, suitable for identifying patients in whom axillary dissection can be avoided.

Axilla↗
PubMed2001

Evaluation of the utility of cephalometric parameters in constructing complete denture. Part II: placement of anterior teeth.

Various types of parameters, including cephalometric ones, have been used in the construction of complete denture. This study aimed to evaluate the utility of cephalometric parameters for this purpose. The position of the anterior teeth in a group of 42 edentulous patients, successfully rehabilitated with complete denture according to clinical parameters, was evaluated by cephalometrics following the Ricketts' design. Data obtained were then compared statistically with those reported by Ricketts for dentate subjects, the position of the maxillary incisors was slightly anterior.

Aged↗
PubMed2001

Influence of the thickness of the resin palatal vault on the closest speaking space with complete dentures.

The closest speaking space (CSS) has been considered stable over time, and therefore useful to determine the vertical dimension of occlusion (VDO) in edentulous patients. Clemençon affirms that, in complete denture wearers, CSS is not constant but depends on the thickness of the resin palatal vault, and that is the air volume needed to pronounce words to remain constant. The aim of this study was to evaluate Clemençon hypothesis in a group of edentulous patients rehabilitated with traditional maxillary denture and mandibular implant anchored overdenture. The CSS was determined by means of a kinematics method using the Elite System(R) at 30, 60, 90, 180, 360 days from delivery. The CSS was assessed twice at each stage: with the unmodified denture and a second time after thickening the resin palatal vault by 2 mm with a calibrated wax layer. The CSS after thickening the resin palatal vault was wider. The wider CSS observed can be because of oro-sensory feedback excited by contact between tongue and palatal vault. As hypothesized by Clemençon thickening the resin palatal vault could be a useful procedure to increase the VDO, in cases in which it is too low from the aesthetic stand point.

Acrylic Resins↗
PubMed2001

Detection of platelet-activating factor in gingival tissue surrounding failed dental implants.

BACKGROUND: Dental implant therapy has entered routine clinical practice. However, the failure rate of implants at 5 years, due to biological factors, is still around 7%. The pathogenesis of implant loss involves a complex network of cells and inflammatory mediators. This study evaluated platelet-activating factor (PAF), a potent phospholipid mediator of inflammation, in soft tissue surrounding failed dental implants versus healthy implants. METHODS: PAF was estimated on extracted lipids by bioassay on washed rabbit platelets; inflammatory cell populations were assessed semiquantitatively after staining, and microvessel density was evaluated after immunohistochemical staining. RESULTS: Biologically active PAF was detected in the lipid extracts of samples excised from gingival tissue of patients with failed implants, but not in samples from patients with osseointegrated implants or from healthy edentulous subjects. The amount of PAF detected in failed implants was significantly higher than in healthy implants, suggesting a local production of this mediator. CONCLUSIONS: The presence of PAF was associated with histopathological findings of local inflammation and increased blood vessel density.

Adult↗
PubMed2001

Evaluation of the utility of cephalometric parameters in constructing complete denture. Part I: placement of posterior teeth.

Various types of parameters, including cephalometric ones, have been used in the construction of complete denture. This study aimed to evaluate the utility of cephalometric parameters for this purpose. The position of the posterior teeth in a group of 42 edentulous patients, successfully rehabilitated with complete denture according to clinical parameters, was evaluated by cephalometrics. The following were determined: vertical dimension of occlusion (VDO); orientation of the occlusal plane; and subdivision of the denture space. The cephalometric parameters do not correspond to the clinical positioning of the posterior teeth in successful rehabilitation with complete denture.

Aged↗
PubMed2001

Coronary artery bypass grafting in patients with dialysis-dependent renal failure: ten-year results.

BACKGROUND: Coronary artery disease has been reported to be accelerated in patients with chronic renal failure on maintenance dialysis. Coronary artery bypass grafting (CABG) in patients on long-term dialysis is still a debated issue. METHODS: We retrospectively reviewed 19 patients (12 men, 7 women, mean age 64 +/- 11.2 years) with end-stage renal disease who underwent CABG between 1990 and 2000. Operative procedures were CABG alone in 15 (78.9%) patients and CABG associated with valve procedures in 4 (21.1%) patients. RESULTS: The early (30-day) mortality rate was 10.5% (2 of 19 patients). Non-fatal complications occurred in 6 patients (31.5%). Four delayed deaths occurred; the actuarial survivals at 1, 2, 5 and 10 years were 0.86 +/- 0.14, 0.78 +/- 0.10, 0.68 +/- 0.13 and 0.54 +/- 0.15 respectively. Among 13 survivors the mean Canadian Cardiovascular Society class was 1.3 +/- 0.3 (p < 0.001 vs preoperatively). ANOVA procedures showed age (p = 0.01), Canadian Cardiovascular Society class > or = III (p < 0.001), urgent/emergency operation (p < 0.001), left ventricular ejection fraction < 0.50 (p < 0.001), a prior myocardial infarction (p = 0.01), a preoperative mean creatinine level > or = 5 mg/dl (p = 0.02) and a duration of dialysis > or = 60 months (p = 0.03) to be strongly related to early and delayed mortality. CONCLUSIONS: CABG in patients with dialysis-dependent chronic renal failure is associated with acceptable results. Accurate patient selection, early referral to surgery, and adequate perioperative management are advisable.

Adult↗
PubMed2000

Cytokine production and bone remodeling in patients wearing overdentures on oral implants.

The stability of titanium dental implants is determined by osseointegration. Bone is a dynamic tissue continuously remodeled through resorption and formation, processes controlled by local cytokine production. This study investigated osseotropic cytokine expression in gingival mucosa, in the intraforamina and inferior first molar zones, during rehabilitation with implant-retained overdentures. Specimens were taken from six patients prior to placement of implants in the intraforamina bone; at connection of healing abutments; and 4, 8, and 12 months after prosthetic anchorage. Through semi-quantitative reverse-transcriptase polymerase chain-reaction, the following constitutively expressed cytokines were found at first surgical stage: interleukin-1, -6, and -8; small amounts of interleukin-11; stem cell factor; and transforming growth factor-beta1, -beta2, and -beta3. From the connection of healing abutments to 12 months after prosthetic anchorage, transforming growth factor-beta1, -beta2, and -beta3 were markedly higher than initial values. Expression of interleukin-6 and -8 decreased 8 months after prosthetic anchorage, while that of interleukin-1 increased at 12 months. In cultured gingival fibroblasts, modulation of cytokine secretion was also time-dependent. Cell culture supernatants influenced osteoclast-like multinucleated cell formation in long-term human marrow culture or osteoblast function, depending on the cytokine profile produced. These results are consistent with functional contributions of cytokines to osseointegration and minimization of posterior edentulous zone bone resorption.

Aged↗
PubMed1999

Bone density in human dentate and edentulous mandibles using computed tomography.

Mandibular bone density, vertebral density and resorption of the edentulous ridge were correlated in a group of 17 partially edentulous subjects. Bone density was quantified by Quantitative Computerized Tomography; resorption was evaluated on panoramic radiographs. Mean bone density in dentate areas was significantly higher than that in edentulous areas; mandibular bone density was not found to relate significantly to vertebral bone density, nor to ridge resorption. In programming osseointegrated implants in the partially edentulous mandible, CT may give a more accurate evaluation of trabecular bone. However, further studies are necessary to clarify its clinical utility.

Adult↗
PubMed1999

Effects on respiratory function of the head-down position and the complete covering of the face by drapes during insertion of the monitoring catheters in the cardiosurgical patient.

BACKGROUND: We evaluated the effect on the respiratory gas exchange of the 30 degrees head-down position and the complete covering of the face by sterile drapes. These are used to cannulate the internal jugular vein and position the pulmonary artery catheter in the cardiosurgical patient. During the two manoeuvres, 20 coronary patients and 10 patients with end-stage heart disease were supplied with oxygen (FiO2 =0.4) by a Venturi mask, while 20 coronary patients breathed room air. The arterial blood samples to measure oxygen (PaO2) and carbon dioxide (PaCO2) tension and oxygen saturation (SaO2) were analysed by a blood gas system. RESULTS: The contemporary application of the head-down position and the drapes over the face significantly increased PaO2 and SaO2 in all the patientssupplied with oxygen. Without the head-down position, leaving the drapes over the face, did not significantly change the two parameters in the coronary patients supplied with oxygen, but induced a significant increase in PaO2 and SaO2 in the patients with end-stage heart disease. In the coronary patients that were breathing room air, PaO2 and SaO2 were stable throughout the study. CONCLUSIONS: We conclude that the 30 degrees head-down position and the complete covering of the face by drapes does not interfere with respiratory gas exchange and can be safely performed in coronary patients supplied with oxygen or breathing room air and in patients with end-stage heart disease supplied with oxygen (FiO2 of 0.4).

Journal Article↗
PubMed1999

Effects of progesterone on human spermatozoa: clinical implications.

Progesterone is a physiological stimulus of human sperm acrosome reaction. The effects of the steroid, which is present in high levels in the cumulus matrix that surrounds the oocyte, are mediated by an increase of intracellular calcium concentrations, tyrosine phosphorylation of proteins, efflux of chloride and stimulation of activity of phospholipases. These effects are due to activation of a nongenomic pathway. Two different types of receptors for progesterone, distinct from the genomic ones, have been identified on the surface of human spermatozoa. We demonstrated that sperm responsiveness to progesterone is impaired in subfertile patients and that is strictly correlated to the ability of fertilize the oocyte. In addition, the determination of sperm responsiveness is predictive of fertilizing ability with a positive predictive value of 90% and can be clinically useful for the preliminary assessment of the male partner to select the appropriate assisted reproductive technique.

Acrosome Reaction↗
PubMed1999

[Preliminary study of the behavior of the rest position and the minimum phonetic distance in edentulous patients rehabilitated with prostheses with modification of the palatal thickness].

BACKGROUND: Various clinical parameters, as well aesthetics, must be taken into account in determining the vertical dimension of occlusion (VDO) when rehabilitating edentulous subjects. These include the freeway space (FS), the physiological rest position (PRP) and the minimum speaking space (MSS). METHODS: Eight edentulous patients were rehabilitated firstly with complete denture; FS and MSS were monitored using a non-invasive computerized system, and increasing the thickness of the denture palate vault. RESULTS: FS and MSS do not appear to be correlated; MSS appears to be more reliable parameter than FS, as it is not influenced by the patient's will. CONCLUSIONS: Increasing the thickness of the palate vault causes a marked lowering of the mandible during speech, in agreement with Clemencon.

Adult↗