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Biomedical subjects

S Rossi

Publications and source records attributed to S Rossi.

At least 181 records · Page 10Linked to original sources
PubMed1999

Morphometric prognostic index in breast cancer.

OBJECTIVE: To assess the ability of the morphometric prognostic index (MPI) in predicting clinical outcome in a group of breast cancer patients with short-term follow-up and to assess the relationship between MPI and other prognosticators. STUDY DESIGN: The study group consisted of 63 cases of breast cancer. Follow-up data were available for 48 patients. MPI values were calculated, and degree of nuclear and tubular differentiation was investigated in each tumor. S-phase fraction (SPF), estrogen and progesterone receptors were also studied. RESULTS: The group of patients with MPI values < 0.60 had percent values of disease-free survival significantly higher than did those with MPI values > or = 0.60. Furthermore, significant direct correlations were found between MPI and degree of nuclear atypia and between MPI and SPF. Significant inverse relationships were found between MPI and tumor progesterone receptor levels and between MPI and degree of histologic tubular differentiation. CONCLUSION: The validity of MPI as a prognosticator in breast cancer was confirmed, even in a limited number of patients observed in short-term follow-up. MPI seems to be a reliable and economical prognosticator in selecting breast cancer patients for adjuvant chemotherapy.

Adenocarcinoma↗
PubMed1999

Marked variation of thymidylate synthase and folylpolyglutamate synthetase gene expression in human colorectal tumors.

Patients with advanced colorectal cancer are currently being treated with 5-fluorouracil (5-FU)-based chemotherapy. A growing number of patients with resectable disease receive adjuvant therapy with 5-FU/levamisole (LEV) or 5-FU/folinic acid (LV). However, many patients still fail on these treatments, due to occurrence of natural or acquired tumor resistance. Among clinically relevant mechanisms of resistance to fluoropyrimidines, increased expression of thymidylate synthase (TS) has been emphasized. Another potentially relevant mechanism involves a decrease in folylpolyglutamate synthetase (FPGS) expression. To establish the value of these genes as prognostic factors and predictors of the outcome of 5-FU-based chemotherapy in colorectal cancer, we measured their expression in colorectal tumors from patients undergoing surgery and postoperative chemotherapy and compared it with that in normal colonic mucosa. This was done by a semi quantitative, nonradioisotopic polymerase chain reaction (PCR) method using beta-actin as an internal standard and expressed as a TS/beta-actin or a FPGS/beta-actin mRNA ratio. In tumor samples from 21 colorectal cancer patients, TS gene expression varied 118-fold. The median TS/beta-actin ratio was, in fact, 41.36 x 10(-3) (range 2.49 x 10(-3) to 294.54 x 10(-3)). Little variation in TS gene expression was observed in corresponding normal colic mucosa; the TS/beta-actin gene ratio was lower (median 26.16 x 10(-3); range 8.49 x 10(-3) to 69.49 x 10(-3)). Among tumor explants from 20 patients, FPGS expression varied over 161-fold. A similar marked variation was also observed in normal colonic mucosal samples (over 185-fold). Overall and disease-free survival data suggest an inverse association between the level of tumor TS and FPGS expression and clinical prognosis. The availability of this sensitive and accurate assay for gene expression should now make it possible to extend these laboratory/clinical correlations to larger populations.

Adult↗
PubMed1998

Advantages in using immobilized thermophilic beta-glycosidase in nonisothermal bioreactors.

Catalytic membranes, obtained by immobilizing thermophilic beta-glycosidase onto nylon supports, were used in a nonisothermal bioreactor to study the effect of temperature gradients on the rate of enzyme reaction. Two experimental approaches were carried out to explain the molecular mechanisms by which the temperature gradients affect enzyme activity. The results showed that the thermophilic enzyme behaved as the mesophilic beta-galactosidase, exhibiting an activity increase which was linearly proportional to the transmembrane temperature difference. The efficiency of the system proposed was determined by calculating two constants, alpha and beta, which represent respectively the percentage increase of enzyme activity when a temperature difference of 1 degrees C or a temperature gradient of 1 degrees C cm-1 were applied across the catalytic membrane. The increase of enzyme activity in nonisothermal bioreactors entailed a proportional reduction of production times. The advantages in using thermophilic enzymes immobilized in nonisothermal bioreactors are also discussed.

Bioreactors↗
PubMed1998

Corticospinal excitability modulation during mental simulation of wrist movements in human subjects.

Motor evoked potentials (MEPs) to magnetic transcranial stimulation (TCS) were simultaneously and bilaterally recorded from flexor carpi radialis (FCR) and extensor communis digitorum (ECD) muscles in seven healthy and trained subjects. Latencies and amplitudes characteristics of MEPs were investigated under the following randomised conditions: muscular and mental relaxation; mental simulation, during absolute muscular relaxation, selective flexion or extension of the right or left wrist muscles; arithmetical calculation with muscular relaxation. Unspecific, diffuse facilitatory effects on MEPs amplitude were induced by mental non motor activity (arithmetical calculation). A further specific and lateralised amplitude potentiation on the agonist muscle acting as 'prime mover' for the mentally simulated movement was consistently found in all the subjects, without significant latency changes. Inhibitory effects on antagonists were evident only in two subjects.

Adult↗
PubMed1998

On the employment of lambda carrageenan in a matrix system. III. Optimization of a lambda carrageenan-HPMC hydrophilic matrix.

The lambda carrageenan/HPMC ratio in matrix tablets has been optimized in order to obtain pH-independent release profiles of chlorpheniramine maleate, a freely soluble drug. Release profiles in acidic (pH1.2) and neutral (pH 6.8) media were fitted according to the Weibull and the power law models. Model independent parameters(t50% and the percentage of drug released after 2 h) were also calculated. The Weibull parameters were found suitable to describe the dependence of the release profiles on matrix composition. Preparation and testing of the optimized formulation showed linear and pH-independent release profiles lasting about 24 h, in good accordance with the values predicted by the optimization procedure.

Carrageenan↗
PubMed1998

CMF + radiotherapy in the primary treatment of operable breast cancer: preliminary results of a phase II pilot study.

BACKGROUND AND OBJECTIVES: Chemotherapy and radiotherapy have been investigated in several studies about their role in primary (neoadjuvant) treatment before surgery in breast cancer. We proposed a pilot study to evaluate a primary scheme of alternate radio-chemotherapy in the treatment of operable (T2- small T3) breast cancer. METHODS: 14 patients were recruited. Cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) were administered on days 1 and 8, every 4 wk, for two cycles. Radiotherapy was administered during the 3rd and 4th wk (5 d/wk) after the beginning of chemotherapy. The patients were operated on within 24 wk. All the patients received four additional cycles of chemotherapy within 1 mo after surgery. RESULTS: We observed: 1 (8.3%) complete remission (CR), 8 (66.7%) partial remission (PR), 3 (25%) stationary disease (SD); no progressive disease was observed. Modified radical mastectomy was performed on 7 patients (58.3%). Conservative surgery was performed on 5 cases (41.7%). No major complications were observed. No patient has shown local or distant recurrence. CONCLUSIONS: This study shows the feasibility of a primary chemoradiotherapy treatment for breast cancer. But to evaluate the impact of this therapy on overall survival and recurrence risk and its possible introduction in clinical practice, we need larger series and longer follow-up.

Adult↗
PubMed1998

Vulvar squamous carcinoma: prognostic role of DNA content.

DNA nuclear content was evaluated on 46 paraffin-embedded blocks of vulvar cancer by means of flow cytometry. Fifteen of 44 evaluable samples (34%) were found to have an aneuploid DNA pattern. Aneuplody showed a statistically significant relationship with tumor grading (P = 0.0004) and defined a subset of patients who have pathological characteristics of high risk, such as advanced stage of disease, deepest stromal invasion, or positive inguinal nodes. However, when a multivariate regression model was used, ploidy status did not have any prognostic role, while FIGO staging system was confirmed to be the strongest independent prognostic factor (P = 0.009). The integration of a panel of cell kinetic parameters with traditional features is worth investigating on a larger population.

Adult↗
PubMed1998

Modulation of corticospinal output to human hand muscles following deprivation of sensory feedback.

Excitability and conductivity of corticospinal tracts of 10 volunteers were investigated by motor-evoked potentials (MEPs) to transcranial magnetic brain stimulation, before and after anesthetic block of right median (sensory + motor) and radial (sensory) nervous fibers at the wrist. MEPs were simultaneously recorded from two ulnar-supplied muscles during full relaxation and voluntary contraction. These muscles maintained an intact strength following anesthesia, but they were in a remarkably different condition with respect to the surrounding skin: the first dorsal interosseous muscle (FDI) was totally "enveloped" within the anesthetized area but was still dispatching a normal proprioceptive feedback; the abductor digiti minimi (ADM) was preserving both cutaneous and proprioceptive information. Spinal and peripheral nerve excitability were monitored as well. The sensory deprivation induced short-term changes which selectively took place within the hemisphere connected to the anesthetized hand. The physiological latency "anticipation" of MEPs recorded during active contraction versus relaxation was reduced (P < 0.001) in the FDI, but not in the ADM, when values during anesthesia were compared with preanesthesia values. The FDI cortical representation-as analyzed by a mapping procedure of the motor cortex via focal stimuli of several scalp positions-was significantly (P < 0.002) reduced, while the ADM representation remained either unchanged or enlarged. MEP and F-wave variability significantly decreased in the FDI but not in the ADM. F-waves were also affected due to changes in the motoneuronal excitability at spinal level. Peripheral nerve and root stimulation showed no modifications. Results are discussed in view of the short-term modifications of the corticospinal pathway somatotopy produced by the selective reduction of the sensory flow. Implications of the sensory feedback in motor control are also discussed.

Contingent Negative Variation↗
PubMed1998

Complications and safety associated with ICP monitoring: a study of 542 patients.

In our institution ICP was monitored in patients with GCS < or = 8 and abnormal CT scan: 362 severely head injured and 180 subarachnoid hemorrhage. Mean duration of monitoring was 103.6 hours (SD 74.96). Among 542 patients, 440 showed at least one episode of ICP above the threshold of 20 mm Hg. Among 362 head injured patients only 71 (19.3%) had an ICP lower than 20 mm Hg. In the remaining 289 (81.7%) at least one episode > or = 20 mm Hg was measured. In 13 cases (2.2%) a ventricular infection has been diagnosed. In 1 case an intraparenchimal hemorrhage related to the presence of the catheter was detected. Elevated risk of HICP and low incidence of complications have been shown in this series.

Adolescent↗
PubMed1998

Estimation of the main factors affecting ICP dynamics by mathematical analysis of PVI tests.

A simplified model of intracranial dynamics is used to reproduce the intracranial pressure (ICP) time pattern in 20 patients with severe brain damage during PVI tests. A comparison of model responses and clinical tracings was achieved by minimizing a least square criterion function and adjusting just 5 parameters. These are: the CSF outflow resistance, the intracranial elastance coefficient, the autoregulation gain and time constant, and the basal values of arteriolar compliance. Based on the value of the autoregulation gain, the patients were classified into two groups: those with damaged autoregulation (8 out of 12) and those with preserved autoregulation (12 out of 20). Finally, analysis of the correlation between parameter estimates provided suggestions on the combination of a parameter changes which may have the greater impact on ICP in the individual cases. Once these parameters have been identified, they may become possible targets for therapeutic interventions.

Blood Flow Velocity↗
PubMed1998

Phospholipid rearrangement of apoptotic membrane does not depend on nuclear activity.

The behaviour of plasma membrane was studied in UV-treated cells to investigate its involvement in apoptosis. It was studied in HL60 cells, in which DNA oligonucleosomic cleavage occurs, and in Molt-4 cells, which are characterised by a different fragmentation pattern. During the early stages of apoptosis, a membrane lipid rearrangement occurs, which involves phosphatidylserine translocation from the inner to the outer leaflet. This molecular alteration was investigated by annexin V-FITC binding, analysed by flow cytometry and confocal microscopy. It was correlated with transmission electron microscopy, subdiploid peak appearance and DNA fragmentation. Our data indicate that the plasma membrane represents an early apoptotic target, even if its alterations are not detectable by ultrastructural analysis, which indicates its good preservation until late apoptotic stages. In addition, the study of apoptotic cells with absent or inactivated endonuclease demonstrates the independence of this membrane mechanism from nuclear activity.

Apoptosis↗
PubMed1998

Clinical applications of motor evoked potentials.

Magnetic stimulation of brain and spinal roots provides a non-invasive evaluation of nervous propagation as well as of motor cortex excitability in healthy subjects and in patients affected by neurological diseases (i.e. multiple sclerosis, stroke, Parkinson's disease, myelopathies etc.). Motor areas can be reliably mapped and short- and long-term 'plastic' changes of neural connections can be studied and monitored over time. By evaluating excitatory and inhibitory phenomena following transcranial stimuli, the mechanisms of action of different drugs, including antiepileptics, can be studied. Moreover, transcranial stimulation of non-motor brain areas represents a probe for the evaluation of lateralized hemispheric properties connected with higher cortical functions. Recent studies suggest a therapeutic role of repetitive magnetic stimulation in psychiatric disorders.

Animals↗
PubMed1998

Treatment of chronic hepatitis D with interferon alpha-2b in patients with human immunodeficiency virus infection.

BACKGROUND/AIMS: Hepatitis delta virus (HDV) coinfection is frequent in patients infected with human immunodeficiency virus (HIV), and it may cause death independently of the development of full-blown AIDS. In order to evaluate the efficacy and tolerability of interferon alpha in the treatment of hepatitis delta in HIV-infected patients, and to compare them with those observed in anti-HIV-seronegative patients, we carried out an open uncontrolled trial on 21 HIV-uninfected and 16 HIV-infected patients without severe immunodeficiency. METHODS: All patients were treated with recombinant interferon alpha 2b (IFN) at doses of 10 million units thrice weekly for 6 months, and 6 million units thrice weekly for an additional 6 months. Patients showing alanine transaminase activity values persistently reduced by at least 50% from basal values received an additional 1-year course of 3 million units thrice weekly. RESULTS: Alanine aminotransferase normalization was observed in 19% of HIV-infected and 14% of HIV-uninfected subjects during the first year; in 12% of HIV-infected and in 9% of HIV-uninfected patients during the second year. Twenty-five percent of HIV-infected and 14% of HIV-uninfected patients stopped IFN because of poor compliance or side effects. Two years after stopping interferon treatment, one anti-HIV-seropositive and two anti-HIV-seronegative patients showed complete persistent biochemical, virological and histologic remission. CONCLUSIONS: Long-term efficacy and toxicity of IFN treatment seem not to be different in HIV-infected and -uninfected patients with delta hepatitis; given the overall poor rate of long-term response, IFN treatment could be considered only in immunocompetent HIV-HDV-coinfected patients, strictly selected because of rapidly evolving liver disease.

Adult↗
PubMed1998

Heterocyclic amine content in beef cooked by different methods to varying degrees of doneness and gravy made from meat drippings.

Meats cooked at high temperatures sometimes contain heterocyclic amines (HCAs) that are known mutagens and animal carcinogens, but their carcinogenic potential in humans has not been established. To investigate the association between HCAs and cancer, sources of exposure to these compounds need to be determined. Beef is the most frequently consumed meat in the United States and for this study we determined HCA values in beef samples cooked in ways to represent US cooking practices, the results of which can be used in epidemiological studies to estimate HCA exposure from dietary questionnaires. We measured five HCAs [2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)] in different types of cooked beef using solid-phase extraction and HPLC. Steak and hamburger patties were pan-fried, oven-broiled, and grilled/barbecued to four levels of doneness (rare, medium, well done or very well done), while beef roasts were oven cooked to three levels of doneness (rare, medium or well done). The measured values of the specific HCAs varied with the cut of beef, cooking method, and doneness level. In general, MeIQx content increased with doneness under each cooking condition for steak and hamburger patties, up to 8.2 ng/g. PhIP was the predominant HCA produced in steak (1.9 to 30 ng/g), but was formed only in very well done fried or grilled hamburger. DiMeIQx was found in trace levels in pan-fried steaks only, while IQ and MeIQ were not detectable in any of the samples. Roast beef did not contain any of the HCAs, but the gravy made from the drippings from well done roasts had 2 ng/g of PhIP and 7 ng/g of MeIQx. Epidemiological studies need to consider the type of meat, cooking method and degree of doneness/surface browning in survey questions to adequately assess an individual's exposure to HCAs.

Animals↗
PubMed1998

Correction of the self-reported BMI in a teenage population.

OBJECTIVE: To investigate the issue of systematic bias in self-reported weight and height, and produce a simple procedure which can be used to correct reporting bias. DESIGN: Cross-sectional, with self-reported questionnaires. SUBJECTS: A sub-sample (n = 143) of secondary school students in Siena, Italy, taken from the Food Behaviour Survey (sample size, n = 779). RESULTS: In the teenage sub-sample, both males and females under-reported their weight and over-reported their height, such that underestimation of the overweight prevalence was in the order of about 8% for both genders. For both weight and height, the correlations between self-reported and measured values were over 0.90. Conversion factors were derived to correct the reported body mass index (BMI) distribution by adjusting the percentages of erroneously classified subjects in the four BMI categories. CONCLUSION: High correlation coefficients (r > or = 0.75), showing a systematic tendency for erroneous self-reporting of a 'slim-body shape', justify the use of conversion factors (measured/self-reported) to correct BMI distributions calculated from self-reported values.

Adolescent↗
PubMed1998

Percutaneous treatment of small hepatic tumors by an expandable RF needle electrode.

OBJECTIVE: The aim of this study was to evaluate the usefulness of expandable RF needle electrodes in the treatment of hepatic cancer. SUBJECTS AND METHODS: Thirty-seven patients, 23 of whom had 26 hepatocellular carcinoma nodules and 14 of whom had 19 hepatic metastatic nodules, underwent treatment by RF interstitial thermal ablation with expandable needle electrodes. Forty-five tumor nodules were treated in 64 RF interstitial thermal ablation sessions with 83 needle electrode insertions. The mean diameter of the tumor nodules was 2.5 cm (range, 1.1-3.5 cm). Immediate posttreatment tumor necrosis was evaluated by dynamic CT in all cases. Two patients with hepatocellular carcinoma and three patients with metastases underwent surgical resection 20-60 days after RF treatment. The remaining 32 patients were followed up clinically. RESULTS: The mean number of RF interstitial thermal ablation sessions to complete tumor nodule treatment was 1.4. Mean number of needle electrode insertions was 1.8. No complications were observed. Posttreatment dynamic CT showed a completely nonenhancing area in the site of the treated tumor in 44 of 45 cases. The remaining patient with metastatic disease had persistent enhancing tissue. Histology showed complete necrosis in four treated tumor nodules and residual viable cancer in one. Twenty-one patients with hepatocellular carcinoma were followed up for 6-19 months (mean, 10 months). Of these patients, six showed recurrences and 15 remained apparently disease-free. Two patients died, one from advanced cancer and one from other causes. Eleven patients with hepatic metastases were followed up for 7-20 months (mean, 12 months). Of these patients, nine showed recurrent disease and only two remained apparently disease-free. Two patients died from disseminated disease. CONCLUSION: RF interstitial thermal ablation of hepatic tumor by expandable needle electrodes is a safe and effective technique. Local ablation of tumors not exceeding 3.5 cm in diameter is achieved in a short time without complications.

Aged↗