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Biomedical subjects

F Silvestri

Publications and source records attributed to F Silvestri.

At least 37 records · Page 2Linked to original sources
PubMed2000

Short-TE projection reconstruction MR microscopy in the evaluation of articular cartilage thickness.

The aim of this study was to assess the potential of projection-reconstruction (PR) MR microscopy in the accurate measurement of cartilage thickness. Short-TE PR microimages were acquired at 7.05 T on bone-cartilage cylindrical plugs excised from four regions of two disarticulated femoral heads (i. e. superior, inferior, posterior and anterior), using an NMR instrument equipped with a microimaging accessory. The PR microimages were then correlated with conventional spin-echo (SE) microimages and with histology. On PR microimages, acquired with an echo time of 3.2 ms, the cartilage signal was increased, allowing an accurate delineation of the cartilage from the tidemark/cortical bone region. As a consequence, by the PR method a more precise measurement of cartilage thickness compared with that performed by the conventional SE approach was feasible. An excellent correlation between PR microimages and histology was also obtained (r = 0.90). By the proposed method it is possible to accurately determine the cartilage thickness better than with the conventional SE sequences.

Aged↗
PubMed2000

Hepatitis c and lymphoma.

Epidemiologic data presented in this review suggest the involvement of hepatitis C virus (HCV) in the patho- genesis of some histotypes of B-cell non-Hodgkin's lymphoma, in particular immunocytoma and lymphomas growing primarily in the liver and major salivary glands. Experimental data further support this hypothesis. Recent findings include demonstration that patients with hematologic malignancies can be treated safely with standard and high-dose chemotherapy even in the presence of HCV infection.

Animals↗
PubMed2000

Articular cartilage repair in rabbits by using suspensions of allogenic chondrocytes in alginate.

The feasibility of allogenic implants of chondrocytes in alginate gels was tested for the reconstruction in vivo of artificially full-thickness-damaged articular rabbit cartilage. The suspensions of chondrocytes in alginate were gelled by the addition of calcium chloride solution directly into the defects giving in situ a construct perfectly inserted and adherent to the subchondral bone and to the walls of intact cartilage. The tissue repair was controlled at 1, 2, 4 and 6 months after the implant by NMR microscopy, synchrotron radiation induced X-ray emission to map the sulfur of glycosaminoglycans and by histochemistry. Practically a complete repair of the defect was observed 4-6 months from the implant of the chondrocytes with the recovery of a normal tissue structure. Controls in which Ca-alginate alone was implanted developed only a fibrous cartilage.

Alginates↗
PubMed2000

Wound closure technique and acute wound complications in gastric surgery for morbid obesity: a prospective randomized trial.

BACKGROUND: During the past 10 years, numerous clinical studies have supported the use of continuous monofilament fascial closure after laparotomy. Because of the increased incidence of surgical-site infections and other acute wound complications in the morbidly obese, these patients are well suited for a study of technical factors that may affect the frequency of these wound complications. STUDY DESIGN: A prospective, randomized study of the midline fascial closure technique in gastric bariatric operations was conducted between 1991 and 1998 in 331 consecutive morbidly obese patients. At the time of closure of the upper midline laparotomy wound, the patients were randomized into two groups: Group I patients (n = 172) underwent continuous fascial closure and group II patients (n = 159) underwent interrupted fascial closure. All patients received prophylactic antibiotics in a similar fashion. Wounds were monitored for 30 days postoperatively, and acute wound complications were classified as superficial or deep. Superficial complications included superficial surgical-site infections, seromas, and hematomas. In all superficial complications, the fascia remained uninvolved and intact. Deep wound complications included deep surgical-site infections and fascial dehiscence. RESULTS: A total of 49 acute wound complications occurred (15%). There were 22 superficial (7%) and 27 deep (8%) wound complications in the 331 in the patients studied. Group I patients experienced fewer total wound complications than group II patients (18 versus 31; p=0.021). Group I patients also experienced fewer deep wound complications than group II (5 versus 22; p = 0.003). CONCLUSIONS: Continuous fascial closure reduces major acute wound complications in morbidly obese patients undergoing gastric operations for obesity.

Cholecystectomy↗
PubMed2000

Lamivudine allows completion of chemotherapy in lymphoma patients with hepatitis B reactivation.

Reactivation of hepatitis B virus in patients receiving chemotherapy for non-Hodgkin's lymphoma (NHL) may give rise to hepatitis, hepatic failure and death, and prevent further chemotherapy. We report four patients with NHL in whom hepatitis flare-up was observed after two (three patients) and six (one patient) cycles of chemotherapy. After spontaneous recovery, they were treated with Lamivudine (100 mg/day), which enabled completion of chemotherapy without further hepatitis B reactivation. In one patient, high-dose chemotherapy and autologous stem cell transplantation was also performed. These data suggest a possible role for Lamivudine in preventing hepatitis B reactivation during chemotherapy administration to chronic carriers of the hepatitis B virus. Moreover, it enabled the completion of both standard and high-dose chemotherapy in patients with previous hepatitis B reactivation.

Adult↗
PubMed2000

Feasibility of autologous stem cell transplantation in chronic carriers of hepatitis B and hepatitis C virus.

There are several reports describing acute liver decompensation in chronic carriers of HBsAg after withdrawal of chemotherapy or immunosuppressive therapy; recently the same was also reported for chronic HCV-RNA carriers. We retrospectively evaluated hepatic toxicity in eleven patients (6 carriers of HCV-RNA and 5 of HBsAg) autotransplanted at our Institution between March '92 and June '98. Male/female ratio was 7/4, median age 41 years (26-56). Nine patients (4 HBsAg) were affected by non-Hodgkin's lymphoma, 1 (HCV-RNA) by chronic myelogenous leukaemia and 1 (HBsAg) by breast cancer. In the immediate post-transplant period in only 1 patient (HBsAg carrier and affected by breast cancer) was hepatitis documented (at about 1 month from transplant) with an elevation of transaminase levels (x20-40 n.v.). Neither other complications, nor toxic deaths were observed. During the post-transplant follow-up (median 31 months, range 9-83) no hepatic abnormalities were observed. All patients are alive at 56 months (20-122) from diagnosis. Currently 10/11 patients are in complete remission, while 1 patient, affected by follicular centre lymphoma, is alive with disease 52 months from autologous stem cell transplantation. Our study shows that both conventional therapy and high-dose chemotherapy can be performed safely in chronic hepatitis B and C virus carriers.

Adult↗
PubMed2000

High-dose therapy in multiple myeloma: effect of positive selection of CD34+ peripheral blood stem cells on hematologic engraftment and clinical outcome.

BACKGROUND AND OBJECTIVE: Positive selection of peripheral blood stem cells (PBSC) has been investigated in multiple myeloma (MM) with the aims of reducing plasma cell (PC) contamination of the leukaphereses and improving clinical outcome of autografted patients. DESIGN AND METHODS: In our center 39 untreated patients with stage II and III MM, younger than 65 years, started high-dose therapy consisting of 4 VAD cycles, collection of PBSC mobilized by 7 g/m(2) cyclophosphamide + G-CSF, and myeloablative treatment with 12 mg/kg busulfan plus 120 mg/m(2) melphalan. The leukaphereses from 23/39 patients (59%) were processed for positive selection of CD34(+) cells using an avidin-biotin immunoaffinity device. RESULTS: A reduction of PC contamination of as much as 2 log was found in the post-selection products by a flow-cytometric technique using the monoclonal antibody CD 138 alternatively coupled with CD38 and cytoplasmatic k or l light chains in separate samples. Hematologic reconstitution and clinical outcome of the 23 patients reinfused with selected CD34(+) cells (SEL group) were compared with those of the 16 patients reinfused with unselected cells (UNSEL group). No significant differences were observed between the 2 groups with regards to the median duration of neutropenia and thrombocytopenia, the hematologic support required, the incidence of febrile episodes and bacteremias. At a median follow-up of 18 months (range 5-34) after ASCT, there were 7/23 (32%) continuous complete remissions (CR) in the SEL group and 4/16 (25%) in the UNSEL group; there were 10/23 (44%) continuous partial remissions (PR) and 5/16 (31%) in the SEL and UNSEL groups, respectively. Two patients in the UNSEL group and one patient in the SEL group died of progressive disease. INTERPRETATION AND CONCLUSIONS: Our data show that positive selection allows rapid engraftment of hematopoiesis and low morbidity. Although no significant difference was detected between the two groups in the frequency of CR and PR 3 and 18 months after ASCT, a longer follow-up is needed to evaluate definitively the effect of CD34(+) selection on the clinical outcome after ASCT.

Adult↗
PubMed2000

The tourniquet revisited as an adjunct to lower limb revascularization.

PURPOSE: The purpose of this study was to evaluate the role and efficacy of the tourniquet in lower limb revascularization. METHODS: During a 3-year period, 195 patients underwent 205 infrainguinal reconstruction operations in the lower extremity. These patients underwent bypass with a tourniquet and inflow occlusion (group 1) or bypass without a tourniquet (group 2). The type of infrainguinal reconstruction, tourniquet ischemia time, blood loss, and complications related to tourniquet use were recorded. A subset of patients underwent serial muscle biopsies. Specimens from calf muscle were taken just (1) before application of the tourniquet, (2) before tourniquet release, and (3) once wound closure was initiated. These biopsy specimens were studied by histochemical staining and also analyzed for phosphorylase enzyme, a marker for subcellular ischemia. RESULTS: One hundred eleven patients underwent 117 infrainguinal reconstruction procedures in which the tourniquet and inflow occlusion were used. These patients were matched against 84 patients who underwent 88 infrainguinal reconstructions without the use of the tourniquet. Complete hemostatic control in group 1 was obtained in 108 of the procedures (92%). Eight percent of the procedures required minor additional techniques to obtain complete hemostasis; in two instances, the tourniquet was removed because it did not provide hemostasis. Mean tourniquet time was less than 1 hour for all reconstruction groups. There were no instances of neurologic deficit, thrombosis of distal vessels, or vascular injury that was related to the use of a tourniquet. A comparison of the two groups revealed no differences with regard to overall blood loss (P =.63) or duration of operation (P = 0.60), observations that reflect the complexity of the cases rather than the use or nonuse of a tourniquet. When tourniquet control was used, we noted a definite decrease in the time for the distal dissection, because total vascular control with extensive dissection was unnecessary. Histochemical analysis with phosphorylase revealed a conversion of tissue with active enzyme activity to a low level with tourniquet use (P <.05). CONCLUSION: The use of a tourniquet for lower limb revascularization is safe and effective and improves visualization of the operative field. Less dissection of the target vessels is required. With a combination of the nonuse of clamps and other occluding devices, we project a decrease in host hyperplastic response that will, in turn, impact favorably on patency rates. The possibility exists that early failure may be prevented by avoiding the application of traumatic forces to diseased and brittle or calcified arteries. In this study, tourniquet time had no impact on overall operative procedural time, although certain phases of the operation were clearly shortened and facilitated, particularly in complex and difficult reconstructions. Histochemical changes found in muscle biopsy specimens did not adversely impact patients clinically, but further investigation is required to elucidate subcellular events.

Aged↗
PubMed1999

Neoplastic thrombotic endocarditis of the tricuspid valve in a patient with carcinoma of the thyroid. Report of a case.

A rare case of neoplastic thrombotic endocarditis of the tricuspid valve in a patient with poorly differentiated follicular carcinoma of the thyroid is described. Although some previous reports documented extension of the follicular thyroid carcinoma into the great veins of the neck to the right cardiac chambers, this seems to be the first report of a neoplastic thrombotic lesion of the tricuspid valve in a patient with thyroid carcinoma. In our institute, where about 2,500 autopsies are performed yearly, and about 600 valvular lesions are discovered, such a lesion was never detected. In patients with carcinoma, a neoplastic thrombotic endocarditis may be a source of microembolic neoplastic spread leading to a possible pulmonary colonisation.

Adenocarcinoma, Follicular↗
PubMed1999

Multicentre European study comparing selection techniques for the isolation of CD34+ cells.

Primitive haemopoietic cells are required for studies in both the clinical and research fields and a number of systems have been developed to facilitate isolation of these haemopoietic cell populations. We have analysed the results from several European centres using positive selection of CD34+ cells from haemopoietic tissues (n = 110). Four selection techniques including immunoaffinity columns (Ceprate LC), immunomagnetic beads (Dynabeads, Baxter Isolex 50) and submicroscopic magnetic beads (MACS) were used and the selected CD34+ cells were assessed for purity, yield and enrichment of colony-forming cells (CFC). The mean purities for all samples ranged from 68.4-78.4% for MACS, 33.9-69.9% for Dynabeads, 46.9-66.8% for Ceprate LC and 43.2-65% for Baxter Isolex 50. Yields were variable with all techniques. On average CFC enrichment using the immunoaffinity columns was greater than that observed for the other systems. Some techniques appear to be problematic and may require further expertise to improve the results. Nevertheless, the study demonstrates that highly purified CD34+ cells can be isolated from various haemopoietic sources, though yield and CFC enrichment varies significantly depending on the technique selected. This extends our previous report indicating that not all selection methods generate similar results and that there are differences in the purity, number and colony-forming ability of the cells recovered.

Antigens, CD34↗
PubMed1999

Autologous bone marrow transplantation in non-Hodgkin's lymphoma patients: effect of a brief course of G-CSF on harvest and recovery.

This study compares harvest and hematological recovery data of 100 lymphoma patients who underwent BM harvest either after a short course of G-CSF (16 microg/kg for 3 days) (n = 57) or in steady-state conditions (n = 43). G-CSF allowed the attainment of a significantly higher median number of total nucleated cells x 10(8)/kg (4.4, range 1.4-17, vs 2.1, range 0.6-4.2; P < 0.0001), mononuclear cells x 10(8)/kg (0.55, range 0.20-1.4, vs 0.41, range 0.15-0.76, P < 0.0001) and CFU-GM/ml (310, range 10-5500, vs 80, range 10-3800, P = 0.008), with lower volumes of blood collected (17.5 ml/kg, range 8-31 vs 21.0, range 15-30, P = 0.0001). Hematological recovery was faster in patients who received pre-treated BM (median time to PMN >0.5 x 10(9)/l and to platelets >20 x 10(9)/l was 12, range 10-14, and 13, range 10-18, days, respectively) than in those autotransplanted with steady-state BM (median time to PMN >0.5 x 10(9)/l and to platelets >20 x 10(9)/l 13, range 10-18 and 14, range 10-20 days, respectively, P = 0.004 and P = 0.01). Transfusional requirement was significantly different and patients of the G-CSF group needed shorter hospitalization (17 days, range 12-24, vs 20 days, range 14-32; P = 0.02). These data suggest that treating patients with G-CSF before BM harvest improves the quality of the harvest and accelerates engraftment and hematological recovery.

Adult↗
PubMed1999

Clinical features and outcome of multiple myeloma arising from the transformation of a monoclonal gammapathy of undetermined significance.

Patients with a monoclonal gammapathy of undetermined significance (MGUS) are usually submitted to a periodical clinical follow-up, but it is not known if this surveillance can ameliorate the prognosis of a plasma cell malignancy that will be eventually detected. We compared the clinical and laboratory characteristics at onset, the response to chemotherapy and the survival, of 21 cases of newly diagnosed multiple myeloma (MM) arising from the malignant transformation of MGUS and 41 cases without a previous history of MGUS, recruited to the same first-line treatments over a 3-years period. The former group showed a significant lower frequency of advanced stages as well as other several prognostic factors of high risk including anemia, renal failure, bone lesions and increase of beta2 microglobulin and C-reactive protein levels. Despite a similar response to treatment of the two groups, MM arising from MGUS showed a significantly longer median survival than MM without prior MGUS. This was particularly true for stage I, while stages II and III behaved similarly. We conclude that the regular clinical monitoring of MGUS patients allowed the identification of earlier malignant transformation, when tumor burden is lower, as indicated by lower beta2 microglobulin levels and marrow plasmacytosis of stage I MM arising from MGUS. Moreover, a slower proliferation rate of myeloma cells, as suggested by lower C-reactive protein levels, may be considered so as to explain the longer survival of these patients.

Aged↗