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Biomedical subjects

F Greco

Publications and source records attributed to F Greco.

At least 73 records · Page 4Linked to original sources
PubMed1993

Hepatitis C virus-related autoimmunity in patients with porphyria cutanea tarda.

Hepatitis C virus (HCV) infection is frequently found in autoimmune hepatitis and mixed cryoglobulinaemia. In these conditions HCV could be responsible for immuno-mediated organ alterations. The aim of this study was to evaluate the presence of immunological alterations in PCT patients, in which HCV infection has been frequently found. Twenty-three PCT patients were evaluated for clinical and serological alterations, including: chronic hepatitis, other systemic symptoms, serum cryoglobulins and rheumatoid factor (RF), haemolytic complement, serum immunoglobulins, anti-nuclear (ANA), anti-smooth muscle (ASMA), anti-liver-kidney-microsomal (anti-LKM1), anti-soluble-liver-antigen (SLA), anti-mitochondrial (AMA), anti-GOR antibodies, anti-HCV and HCV RNA. Abnormal serum ALT were present in the majority of cases (20/23, 87%), while liver biopsy revealed a chronic persistent hepatitis or chronic active hepatitis in 15/20 (75%) PCT patients. In a high percentage of subjects (91%) the presence of anti-HCV was detected by ELISA and RIBA II (Chiron, Emeryville CA, USA). In 17/22 (77%) cases the ongoing HCV replication in the serum was demonstrated by the detection of HCV genomes (polymerase chain reaction). The prevalence of both anti-HCV and HCV RNA in PCT was significantly higher if compared to 22 systemic immunological diseases (P < 0.001) and 47 healthy subjects (P < 0.001). A possible HCV-induced autoimmunity in PCT was suggested by the presence of the following immunological parameter alterations: anti-GOR in 13/23 (57%), ANA in 4/23 (17%), ASMA in 18/23 (78%), anti-LKM1 in 1/23 (4%), RF in 23/23 (100%), mixed cryoglobulins in 4/23 (17%), complement consumption in 10/23 (43%).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Chronic staphylococcal osteomyelitis: a new experimental rat model.

A rat model of chronic staphylococcal osteomyelitis was developed. Fibrin glue (5 microliters) and Staphylococcus aureus (2 x 10(6) CFU/5 microliters) were inoculated into the proximal metaphysis of the tibia. The rats were killed at intervals of between 1 and 6 months, and the tibias were removed. Induced lesions were evaluated by radiographic, macroscopic, and histological examinations and bacterial counts. Roentgenograms revealed osteomyelitis in more than 90% of the tibias. Gross bone pathology revealed skeletal deformation, new bone formation, abscesses, and draining skin fistulas in more than 80% of cases. Histological examination revealed osteomyelitis in more than 90% of cases, and bacterial counts were positive in 86% of cases. Only fibrin glue (5 microliters) was inoculated into controls. Controls showed no osteomyelitic lesions, and counts were negative in seven of eight control tibias. The main feature of this model is the use of fibrin glue instead of the sclerosing agents and foreign bodies used in other models. The model reproduces lesions similar to those of human posttraumatic osteomyelitis and can be reliably used in pathophysiological and therapeutic studies.

Animals↗
PubMed1993

Interferon alfa-2b in mixed cryoglobulinaemia: a controlled crossover trial.

To confirm the positive results of a preliminary trial, 26 patients with mixed cryoglobulinaemia were enrolled in a controlled, randomised, crossover trial with interferon alfa-2b. A significant improvement was seen in the purpura score and alanine aminotransferase activities during six months' treatment, and was associated with a significant decrease in cryocrit and a returning to normal of the lymphocyte CD4/CD8 ratio (in eight of nine patients). No significant variations were seen during the six month period without interferon. Only six patients withdrew from treatment, three because of side effects and three because of poor compliance.

Cryoglobulinemia↗
PubMed1993

Cryoglobulinemic membranoproliferative glomerulonephritis associated with hepatitis C virus.

A striking association between hepatitis C virus (HCV) and mixed cryoglobulinemia (MC) has been reported by various authors, regardless of the presence of chronic hepatitis. The aim of this study is to evaluate the prevalence of HCV-related markers in cryoglobulinemic membranoproliferative glomerulonephritis (MPGN) which is one of the most severe complications of MC. Antibodies against HCV have been detected by second-generation Chiron ELISA and RIBA in 26/26 (100%) cryoglobulinemic MPGN. In addition, serum HCV RNA, expression of the ongoing viral replication, was present in 7/7 patients by the polymerase chain reaction technique. The high percentage of anti-HCV seropositivity suggests that this virus may play an important role in the pathogenesis of this immunemediated glomerulonephritis.

Cryoglobulinemia↗
PubMed1993

Clinical and pathological aspects of solitary spinal neurofibroma.

Four cases are described of solitary spinal neurofibroma, a rare tumour of the spinal cord or nerve roots. Computerised tomography provided an accurate topographical definition of the tumour. Magnetic resonance imaging showed an increased T2-weighted signal and multiple areas of decreased T1- and T2-weighted signals centrally. The MR signals matched the histological examination which showed hyperplastic interfascicular connective tissue, pleomorphic cells, and tightly packed nerve fibres compressed by the surrounding loose connective tissue. Electron microscopy showed three types of cell: Schwann cells, fibroblast-like cells, and mast cells. The histological findings suggests that solitary spinal neurofibroma is a distinct pathological entity which could be diagnosed preoperatively from the MR images.

Adult↗
PubMed1993

The role of instrumental diagnostic methods in the staging of Sudeck's disease.

Forty patients with Sudeck's atrophy were assessed in order to evaluate the diagnostic accuracy of x-ray, scintigraphy and telethermography in staging the 3 phases of the disease. The dynamic and early static phases of scintigraphy were the most sensitive and specific instrumental tests for detecting the early stage, whereas telethermography was fairly sensitive but not very specific. Radiographic examination was not sensitive in detecting slight changes in bone density, but it was the most reliable index for recognizing the transition to stage II of the disease. Moreover, it was possible to confirm that the late static phase of scintigraphy is the index which is best related to bone metabolism.

Adult↗
PubMed1993

[Transesophageal Doppler study of pulmonary venous flow: the role of atrial contraction].

Pulmonary venous flow (PVF) pattern can be easily recorded by using transesophageal Doppler echocardiography. Recent reports suggest that the analysis of PVF pattern could be useful to better understand the role of atrial contraction on left ventricular filling. In order to evaluate the effect of loss of atrial contraction, we studied 50 consecutive patients with atrial fibrillation. We then compared the PVF pattern of atrial fibrillation with the normal pattern obtained from 20 healthy subjects. The reversal flow (A wave) resulting from atrial contraction was lost in patients with atrial fibrillation. The systolic flow was composed by 1 wave in almost all the patients and the peak velocity was reduced compared to normal sinus rhythm. On the contrary, the diastolic flow was increased comparing to normal subjects. In atrial fibrillation the flow shifted from systolic to diastolic filling. The restore of sinus rhythm induced a normalization of PVF pattern.

Adult↗
PubMed1993

Critical analysis of intramedullary nailing by the Ender method in the treatment of intertrochanteric fractures.

A retrospective study was carried out to evaluate the results of intramedullary fixation by Ender nailing in the treatment of intertrochanteric fractures. During the period 1980-1989, 85 patients were treated with this method at the Orthopedic Department of the Università Cattolica in Rome. Evaluation of the cases took into account the patient's characteristics (age, sex, weight, height, obesity, previous or concomitant illness, level of autonomy, mental condition, type of fracture, time elapsed before operation and laboratory tests), details of the operation (length, accuracy of reduction and mechanical fixation stability, post-operative hospitalization period and general and local complications) and follow-up evaluation (X-ray examination, functional examination and evaluation of the results). Analysis of the observations showed that, although it induced less surgical trauma, internal fixation by the Ender method did not ensure a stable reduction, particularly with highly comminuted and basicervical fractures. As a result, the elective indication for this method should be restricted to stable intertrochanteric fractures, particularly in patients with a generally poor condition.

Aged↗
PubMed1992

H-NMR studies of native and fragmented subtilisin Carlsberg.

NMR studies have been carried out on subtilisin Carlsberg in order to identify the sharp resonances observed in the proton spectra of the enzyme dissolved in aqueous solution. NMR spectra, obtained with the combination of spin-echo and selective excitation sequences, from both the native and inactivated protein, enabled us to assign sharp signals to subtilisin fragments derived from enzymatic autolysis (monitored by high-performance size-exclusion chromatography), rather than to mobile segments of the intact protein.

Chromatography, High Pressure Liquid↗
PubMed1992

Polymethylmethacrylate-antiblastic drug compounds: an in vitro study assessing the cytotoxic effect in cancer cell lines--a new method for local chemotherapy of bone metastasis.

An in vitro study was performed assessing the pharmacologic properties of polymethylmethacrylate (PMMA)-antiblastic agent (doxorubicin and cisplatinum) mixtures in normal and neoplastic cell lines cultures. The study's aim was to analyze the polymerization capacity of PMMA in the presence of doxorubicin and cisplatinum, the release of drug from the mixture, the kinetics of release, and the effect of the released drugs in normal and neoplastic cell cultures. Our data show that even at high concentrations neither doxorubicin nor cisplatinum inhibit the polymerization of PMMA. Moreover, mixtures in vitro can release the antiblastic drug which maintains its pharmacologic activity on sensitive neoplastic cells. Therefore, the PMMA-antiblastic drug mixtures, along with current anti-cancer therapy (systemic chemotherapy and radiation therapy), may provide better local control of the metastatic lesion and of some bone tumors.

Bone Neoplasms↗
PubMed1992

The ultrastructure of peripheral neurofibroma: the role of mast cells and their interaction with perineurial cells.

The authors analyze the ultrastructure of mast cells and perineurial cells when both are present in neurofibroma of the nerve sheath. Samples of pathologic tissue taken from three patients with neurofibroma of a peripheral nerve sheath were analyzed by light and transmission electron microscopy. The observations document the characteristics of the tumor cells (Schwann cells and perineurial cells) as well as the presence of numerous mast cells, typically in close contact with the perineurial cells and never with the Schwann cells. Many electron-dense vesicles were found between the cells; these vesicles are created when the cell membrane of the mast cell buds, and then they come into contact with the adjacent perineurial cell. Endocytosis vesicles are often present in the cytoplasm of perineurial cells. Analysis of these observations led the authors to assume the existence of a metabolic interaction between the two cell type in contact with each other and an active role of the mast cells in the evolution of the tumor. The following two theories are plausible: either the mast cells actively stimulate tumor growth, or they alter the phenotype of the tumor cell. These findings could have interesting clinical applications. The use of treatment protocols which inhibit mast cell activity could, in theory, stop either the proliferation of the neurofibroma or its malignant transformation.

Cell Division↗
PubMed1992

Ultrastructural analysis of the adaptation of articular cartilage to mechanical stimulation.

Ultrastructural analysis was conducted on samples of articular cartilage taken from both load-bearing and non-load-bearing areas with the aim of evaluating the morphologic adaptation of the articular cartilage to mechanical stimulation and identifying the mechanisms of interaction of the chondrocyte and the matrix. Through this analysis we were able to better define the adaptation process of the cartilage as well as the modalities of mechanical stress transmission. We believe that the complex formed by the chondrocyte, the pericellular matrix, and the pericellular capsule constitutes the biomechanical unit of the articular cartilage which serves as the sensor and transducer of mechanical stress. The arrangement of the collagen fibers and the proteoglycans which make up the pericellular capsule and membrane around the chondrocyte can be compared, from a mechanical standpoint, to a dynamic structure constructed in order to absorb the load stresses and protect the internal environment. From a biological standpoint, these are comparable to an extracellular-scaffold constructed with the aim of mediating the interaction between the chondrocyte and the territorial and inter-territorial compartments.

Adaptation, Physiological↗
PubMed1992

Intra-articular osteoid osteoma.

The joint is a relatively rare localization for osteoid osteoma. The location of the tumor and the concomitant synovitis-explain the peculiarity of the clinical features, which makes differential diagnosis with inflammatory diseases of the joint difficult. The authors report the results of three cases of intra-articular osteoid osteoma in which it was possible to determine the levels of prostaglandin (PGE2) and prostacyclin (PGI2), which are synthesized by the tumoral tissue. The increased production of these substances, which can reach up to 70 times their production in normal tissue, explain both the character of the pain and the origin of the synovitis which is so commonly found in this kind of tumor. The results of this study confirm the ability of the neoplastic tissue to produce high quantities of mediators of inflammation and enable the authors to formulate a theory as to the pathogenesis of the concomitant reactive synovitis observed in cases of intra-articular osteoid osteoma.

6-Ketoprostaglandin F1 alpha↗