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Biomedical subjects

Francesco Greco

Publications and source records attributed to Francesco Greco.

At least 19 recordsLinked to original sources
PubMed2006

Photorefractivity of poly-N-vinylindole-based materials as compared with that of poly-N-vinylcarbazole-based blends.

The asymmetric two-beam coupling technique has been employed to measure the photorefractivity of thin films of polymer blends containing 2,5-dimethyl-4-(p-nitrophenylazo)anisole as the nonlinear optical component. Poly-(1-vinylindole) and poly-(2,3-dimethyl-1-vinylindole) were the photoconductive polymer counterparts. The values of the photorefractivity are reported. It appears that they are comparable with those of similar blends based on the well-known poly-(9-vinylcarbazole) (PVK), here considered as a reference standard. Careful differential scanning calorimetry analyses have been accomplished on the different blends taken into account to rationalize the significantly longer shelf lifetime of the indolyl-based films with respect to the PVK-based blends.

Journal Article↗
PubMed2006

Impaired in-vitro growth of megakaryocytic colonies derived from CD34 cells of HIV-1-infected patients with active viral replication.

OBJECTIVE: To address the mechanisms of the thrombocytopoietic dysfunction that may follow HIV infection and to compare peripheral blood and bone marrow as sources of CD34 progenitor cells in HIV-infected patients. METHODS: The study used CD34 progenitor cells from 20 previously untreated HIV-infected individuals, 20 HIV-infected individuals treated with antiretroviral therapy and a control group of 20 HIV-uninfected healthy individuals to examine in-vitro megakaryocytopoiesis. There were no hematological abnormalities at baseline in the study groups. CD34 progenitor cells derived from peripheral blood and bone marrow were purified and cultured in medium containing thrombopoietin, interleukin-3, and interleukin-6. HIV-1 plasma viral load was determined by b-DNA technique. Expression of receptors for thrombopoietin, interleukin-3, and interleukin-6 was assessed on CD34 cells by flow cytometry, and numbers of receptors per single cell were calculated by Quanticalc software. RESULTS: Growth of megakaryocytopoietic colony-forming units (CFU-MK) were impaired in untreated HIV-infected individuals despite normal platelet counts. Viral load levels inversely correlate with CFU-MK growth and platelet counts. Antiretroviral drug-treated individuals showed normal megakaryocyte development. Similar results were obtained whether the CD34 progenitor cells derived from peripheral blood or bone marrow. CONCLUSIONS: These findings suggest that megakaryocyte differentiation is impaired before the onset of overt thrombocytopenia in HIV-infected patients and provide evidence for a direct link between viral replication and perturbed megakaryocytopoiesis, which appears to be prevented and/or restored by antiretroviral therapy. The results indicate that peripheral blood represents a suitable source of CD34 hematopoietic progenitors for studies of megakaryocytopoiesis in HIV disease.

Antigens, CD34↗
PubMed2006

Membrane-seeded autologous chondrocytes: cell viability and characterization at surgery.

The implantation of chondrocytes, seeded on matrices such as hyaluronic acid or collagen membranes, is a method that is being widely used for the treatment of chondral defects. The aim of the present study was to evaluate the distribution, viability and phenotype expression of the cells seeded on a collagen membrane just at the time of the implantation. Twelve patients who were suffering from articular cartilage lesions were treated by the MACI procedure. The residual part of each membrane was tested by colorimetric assay (MTT) and histochemical and ultrastructural analyses were carried out. In all of the samples a large number of viable cells, quite homogenously distributed, was detected. The cells expressed the markers of the differentiated hyaline chondrocytes. These data reassure in that the MACI procedure provides a suitable engineered tissue for cartilage repair, in line with the clinical evidences emerging in the literature.

Adult↗
PubMed2005

Results after laparoscopic adjustable gastric banding in patients over 55 years of age.

BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) has become the most popular bariatric intervention in Europe. International guidelines recommended age limits for bariatric surgery of 18-60 years. The aim of this study was to evaluate the immediate results in morbidly obese patients >55 years old, treated with LAGB. METHODS: Between January 1996 and January 2004, 350 patients underwent LAGB. 24 (6.8%) were >55 years old (Group A), mean age 58.6+/-3.3 years, mean preoperative BMI 42.3+/-4.5 kg/m2. A comparative randomized analysis with 24 patients younger than age 55 years was performed (Group B: mean age 41.2+/-9.6 years, mean BMI 42.1+/-3.6 kg/m2). Baseline clinical features, operative parameters and postoperative results were evaluated. RESULTS: No perioperative complications were recorded. Conversion rate and mortality were nil. Major postoperative complications occurred in 2 patients (8.3%) from Group A (1 intragastric prosthesis migration, 1 pouch dilatation) and 2 patients (8.3%) from Group B (intragastric migrations). Reoperation was needed in 3 cases, and one erosion (Group B) is on the waiting list for removal. Minor complications: 1 port infection in each group required ambulatory port substitution; 1 intraperitoneal portcatheter disconnection (Group B) was successfully treated laparoscopically. Mean follow-up was 31.7 months (Group A) and 33.0 months (Group B). Mean postoperative BMI at 12 and 24 months was 35.9+/-4.2 and 33.8+/-4.9 for Group A, and 33.8+/-4.6 and 33.2+/-6.0 for Group B. CONCLUSION: There have been no significant differences in results between the 2 groups. LAGB has been safe and effective in patients >55 years old.

Adult↗
PubMed2005

Prevalence of cancer in Italian obese patients referred for bariatric surgery.

BACKGROUND: An association between obesity and cancer has been shown in large epidemiological studies. The aim of this study was to evaluate the prevalence and types of malignancies in an Italian cohort of obese patients referred to a bariatric center. METHODS: A retrospective, observational study was conducted. Between Jan 1996 and Dec 2004, 1,333 obese patients (M=369, F=964) were seen in the center for minimally invasive treatment of morbid obesity. Morbid obesity were considered as BMI >40 kg/m(2) or BMI >35 kg/m(2) with at least one co-morbidity. Obese and morbidly obese patients who suffered any form of cancer were reviewed. RESULTS: 43 patients (3.2%) presented various malignancies, with 88.3% in females. The prevalence of cancer in the younger group (21-46 years) was higher than in the older group (47-70 years), 2.1% vs 1.1%. 26 obese patients out of the 43 (60.5%) (age 41+/-7.9 years, BMI 38.2+/-9.9) presented hormone-related tumors. The most frequent site of cancer was breast (20.9%), followed closely by thyroid. CONCLUSION: This is the first Italian report on prevalence of cancer in a homogeneous obese population attending an academic bariatric center. The morbidly obese patients appear to have a higher risk of developing cancer, with a higher prevalence of hormone-related tumors. The predominant gender affected by both obesity and cancer was female. Thus, a preoperative work-up for cancer screening is indicated in this group of patients.

Adolescent↗
PubMed2005

[Echocardiography in the diagnostic and prognostic evaluation of thromboembolic pulmonary hypertension].

Pulmonary arterial hypertension frequently develops after a thromboembolic pulmonary event. The difference in degree of pulmonary artery pressure depends mainly on the size and location of the pulmonary embolus and presence of pre-existing cardiopulmonary diseases. Right ventricle (RV) afterloading from an acute obstruction of the pulmonary vasculature causes an increase of RV volume and dysfunction of right heart cavities, the varying levels of severity of which explain the multiple clinical expression of pulmonary embolism (PE). While the diagnostic approach, therapeutic management and prognostic evaluation are now well defined, the natural progression of PE is still not completely understood. In particular, insufficient data exist on the rate, timing and modalities of development of chronic thromboembolic pulmonary hypertension (CTPH). The aim of this review is to evaluate the role of echocardiography in detecting patients with CTPH, and in assessing hemodynamic consequences on RV and related prognostic implications.

Chronic Disease↗
PubMed2005

Importance of troponin T for the risk stratification of normotensive patients with pulmonary embolism. A prospective, cohort study with a three-month follow-up.

To determine the prognostic importance of troponin T in normotensive patients with pulmonary embolism, we investigated the rate of adverse events in patients with normal and elevated troponin values, during the hospital period and at three months of follow-up. We also calculated the proportion of patients with abnormal troponin values and adverse outcomes who could have been treated with more aggressive therapy according to published criteria.

Aged↗
PubMed2005

Pulmonary embolism: treatment of the acute episode.

The prognosis of acute pulmonary embolism (PE) is mainly related to the clinical presentation and circulatory state of the patient: the therapeutic strategy is consequently different, ranging from an aggressive treatment in patients in life-threatening clinical conditions to a "stabilization" treatment in those hemodynamically stable. Since the majority of PE patients are clinically stable, a well conducted anticoagulant therapy, either with unfractionated or low-molecular-weight heparins together with a vitamin K antagonist, is sufficient to stop thrombus extension, to minimize the risk of recurrent embolism and prevent mortality. In about 15-20% of cases presenting with clinical instability of variable severity, prompt intravenous thrombolysis with a short-acting compound often represents a life-saving treatment and should be the first-line approach. In normotensive patients with right ventricular dysfunction at echocardiography, who represent about 30% of PE patients, the debate regarding the optimal therapy is still open and further studies are required to document a clinically relevant improvement in the benefit-risk ratio of thrombolytic agents over heparin alone: young people, with a very low risk of bleeding and a concomitant reduction of cardiopulmonary reserve might be the best candidates to systemic thrombolysis. In any case such patients should be admitted to an intensive care unit to monitor the clinical status for at least 48-72 hours and detect signs of possible hemodynamic worsening. Mechanical thrombectomy, either percutaneous or surgical, are ancillary procedures and should be reserved to a minority of highly compromised patients who are unable to receive thrombolysis.

Acute Disease↗
PubMed2004

Highly entangled polymer primitive chain network simulations based on dynamic tube dilation.

The concept of dynamic tube dilation (DTD) is here used to formulate a new simulation scheme to obtain the linear viscoelastic response of long chains with a large number of entanglements. The new scheme is based on the primitive chain network model previously proposed by some of the authors, and successfully employed to simulate linear and nonlinear behavior of moderately entangled polymers. Scaling laws are generated by the DTD concept, and allow for prediction of the linear response of very long chains on the basis of suitable simulations performed on shorter ones, without introducing adjustable parameters. Tests of the method against existing data for linear monodisperse polyisoprene and polystyrene show good quantitative agreement.

Journal Article↗
PubMed2004

Role of a minimally invasive approach in the management of laparoscopic adjustable gastric banding postoperative complications.

HYPOTHESIS: Complications after laparoscopic adjustable gastric banding as treatment for morbid obesity may require a major reintervention. A minimally invasive approach represents an attractive management alternative for such complications. DESIGN: Prospective case series. SETTING: Major academic medical and surgical center. PATIENTS: From January 1996 to July 2003, 47 patients who had undergone laparoscopic adjustable gastric banding were operated on again. Considering the causes for reoperation, the patients were divided into 4 groups: group A had major complications (n = 26); group B, minor complications (n= 11); group C, psychological problems (n=6); and group D, insufficient weight loss (n=4). INTERVENTIONS: Forty-three procedures, 38 using general anesthesia (groups A, C, and D) and 5 using local anesthesia (group B), were performed. MAIN OUTCOME MEASURES: Feasibility, safety, and effectiveness of a minimally invasive approach in the treatment of laparoscopic adjustable gastric banding complications. RESULTS: In group A, 9 of 10 patients with irreversible gastric pouch dilatation and 15 of 16 with intragastric band migrations were treated laparoscopically. In group B, 5 ports were substituted and 2 reconnections of the catheter-port system were performed. In group C, 6 laparoscopic band removals were carried out. In group D, 4 laparoscopic revision procedures for insufficient weight loss were performed. The operative mortality was nil. The most frequent cause of reoperation was intragastric migration (37.2%). A minimally invasive approach was adopted in 94.7% of cases. CONCLUSION: Laparoscopy is safe and effective, even as a second operative procedure.

Adult↗
PubMed2004

Incidence of post-thrombotic syndrome in patients with previous pulmonary embolism. A retrospective cohort study.

There is little information available about the true incidence of post-thrombotic syndrome (PTS) after pulmonary embolism (PE). The aim of this study was to investigate the incidence of PTS in patients with previous pulmonary embolism without concomitant ultrasonographically-detectable deep vein thrombosis (DVT). A retrospective cohort study was conducted at a single tertiary care centre, Cosenza, Italy. Forty-seven consecutive patients with proved PE without DVT within the previous 2 to 6 years, 45 patients with previous DVT in the same years, and 45 patients with diseases unrelated to venous thromboembolism (VTE) underwent a blind assessment for PTS using a clinical score. Two of 47 (4.2%, 95%CI: 0.01-9.9) patients with PE, 2 of 45 (4.4%, 95%CI: 0.01-10.4) patients with diseases unrelated to VTE, and 23 of 45 (53.3%, 95%CI: 38.7-67.9) patients with DVT showed signs and symptoms of PTS. The difference between the first two groups was not statistically significant (p = 0.7). In conclusion, the incidence of PTS after pulmonary embolism without DVT is low, and no different from that of patients without previous VTE.

Adult↗
PubMed2003

Arthroscopy-assisted reduction and percutaneous fixation of a multiple glenoid fracture.

Glenoid fractures are rare. The traditional method for treating them is open reduction and internal fixation in arthrotomy. Arthroscopic reduction with percutaneous fixation is used in selected fractures (of tibial plateau, ankle, distal radius). We describe the surgical technique adopted to treat a multiple, Y-shaped articular glenoid fracture using arthroscopy and percutaneous fixation.

Adult↗
PubMed2003

Responsiveness of Dupuytren's disease fibroblasts to 5 alpha-dihydrotestosterone.

PURPOSE: We recently showed that androgen receptors are expressed in Dupuytren's contracture. The aim of the present work was to test the responsiveness of Dupuytren's fibroblasts to 5 alpha-dihydrotestosterone (5 alpha-DHT), the active form of testosterone. RESULTS: Cultured palmar fascia cells from 10 patients with Dupuytren's contracture and 4 normal subjects were exposed to 5 alpha-DHT (10 or 100 ng/mL) for 1, 3, 7, and 15 days. Their phenotype was analyzed immunohistochemically for alpha-smooth muscle actin and androgen receptor expression and proliferation rates were studied. RESULTS: At 15 days the higher concentration of 5 alpha-DHT induced an increase in Dupuytren's fibroblast proliferation, whereas anti-alpha-smooth muscle actin exhibited the strongest expression. At the same time point androgen receptor expression decreased with the lower concentration and disappeared altogether with the higher dose of 5 alpha-DHT. CONCLUSIONS: The palmar fascia is a target tissue for androgen action via androgen receptors. Further studies are required to determine whether control of androgen receptor may control the evolution of Dupuytren's disease.

Actins↗
PubMed2003

Diagnostic utility of echocardiography in patients with suspected pulmonary embolism.

The aim of this study was to investigate the clinical utility of echocardiography in the diagnosis of pulmonary embolism (PE). For this, we enrolled 162 patients with suspected PE in a prospective study. We evaluated the sensitivity and specificity of right ventricular dilatation, the Doppler evidence of pulmonary hypertension, and their possible associations. We also calculated the number of lung-scan angiography procedures avoided and the number of patients unnecessarily treated when echocardiography was included in the diagnostic work-up. The sensitivity and specificity of echocardiography ranged between 29 and 52% and between 96% and 87%, respectively. Adding echocardiography to the diagnostic strategy for PE would avoid about 12 to 28% of lung-scan angiography procedures, but would cause inappropriate treatment of 4 to 14% of all treated patients. The clinical utility of echocardiography in the diagnosis of PE is limited. The reduction in the number of standard diagnostic procedures obtained through its use would be counterbalanced by an excess of patients inappropriately treated.

Adolescent↗
PubMed2003

Engineered articular cartilage: influence of the scaffold on cell phenotype and proliferation.

Articular cartilage defects do not heal. Biodegradable scaffolds have been studied for cartilage engineering in order to implant autologous chondrocytes and help cartilage repair. We tested some new collagen matrices differing in collagen type, origin, structure and methods of extraction and purification, and compared the behavior of human chondrocytes cultured on them. Human chondrocytes were grown for three weeks on four different equine type I collagen matrices, one type I, III porcine collagen matrix and one porcine type II collagen matrix. After 21 days, samples were subjected to histochemical, immunohistochemical and histomorphometric analysis to study phenotype expression and cell adhesion. At 7, 14 and 21 days cell proliferation was studied by incorporation of [3H]-thymidine. Our data evidence that the collagen type influences cell morphology, adhesion and growth; indeed, cellularity and rate of proliferation were significantly higher and cells were rounder on the collagen II matrix than on either of the collagen I matrices. Among the collagen I matrices, we observed a great variability in terms of cell adhesion and proliferation. The present study allowed us to identify one type I collagen matrix and one type II collagen matrix that could be usefully employed as a scaffold for chondrocyte transplantation.

Journal Article↗
PubMed2003

Effects of elastin-derived peptide on Achilles' tendon healing: an experimental study.

Different matrix macromolecules modulate the tendon healing process. Elastin contains sequences which exhibit chemotactic activity both in vitro and in vivo. We analyzed the effects of synthetic elastin-derived peptide Val-Gly-Val-Ala-Pro-Gly suspended in a gel solution on the healing process of Achilles' tendon in a rat model. A total tenotomy at the middle 3rd was performed in 32 rats. During the suture repair the gel with (Group A) or without (Group B) the elastin-derived peptide was applied to the tendon stumps. Four animals for each period and group were killed at 10, 30, 60 and 90 days after surgery. The scar tissue was processed for histochemical, immuno-histochemical and morphometric analysis. An improved healing process with increase in cellularity and vascularity, especially at the early stage of the Achilles' tendon healing process was observed in Group A compared to Group B. The fiber alignment was also positively influenced by the factor. Immunolabeling with HAM 56 and lisozyme revealed a stronger reaction for the presence of monocyte/macrophage in Group A vs Group B especially in early stages. Chondral metaplasia and endochondral ossification occurred in the healed tissue of both group at 60 and 90 days.

Journal Article↗
PubMed2003

Increased external tibial torsion in Osgood-Schlatter disease.

We studied the relationship between Osgood-Schlatter disease and torsional abnormalities of the lower limb in 21 boys with this condition and 20 age- and sex-matched controls. 3 groups of knees (20 control knees, 21 symptomatic and 21 asymptomatic or less symptomatic knees) were subjected to clinical, radiographic and CT evaluation. We found no statistically significant differences between patients and controls, as regards femoral anteversion, patellar congruence angle, patellar tilt angle and anterior tibial tuberosity-trochlear groove distance, but the condylomalleolar angle and tibial torsion angle were greater in patients. We found no differences between symptomatic and asymptomatic or less symptomatic knees in any of the parameters. All the symptomatic knees were on the side preferentially involved in jumping and sprinting. This increase in external tibial torsion may play a role as a predisposing mechanical factor in the onset of Osgood-Schlatter disease in male athletes.

Adolescent↗