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Biomedical subjects

M Natali

Publications and source records attributed to M Natali.

16 recordsLinked to original sources
PubMed2002

Correlated magnetic vortex chains in mesoscopic cobalt dot arrays.

Nucleation and annihilation of vortex states have been studied in two-dimensional arrays of densely packed cobalt dots. A clear signature of dipolar interactions both between single-domain state dots and vortex state dots has been observed from the dependence of vortex nucleation and annihilation fields on interdot separation. A direct consequence of these interactions is the formation of vortex chains as well as dipole chains aligned along the direction of the external field. In addition, short range correlation of chiralities within vortex chains has been observed using magnetic force microscopy imaging and has been attributed to cross-talking between adjacent elements.

Journal Article↗
PubMed2002

Magnetic domain confinement by anisotropy modulation.

The spin configuration in a magnet is in general a "natural" consequence of both the intrinsic properties of the material and the sample dimensions. We demonstrate that this limitation can be overcome in a homogeneous ferromagnetic film by engineering an anisotropy contrast. Substrates with laterally modulated single-crystal and polycrystalline surface regions were used to induce selective epitaxial growth of a ferromagnetic Ni film. The resulting spatially varying magnetic anisotropy leads to regular perpendicular and in-plane magnetic domains, separated by a new type of magnetic wall---the "anisotropy constrained" magnetic wall.

Journal Article↗
PubMed2002

Spin-engineering magnetic media.

The explosion in demand for increased data-storage density is driving the exploration of new magnetic media. Here we describe a new type of magnetic medium in which the spin configurations are engineered in chemically homogeneous magnetic films: regularly arranged in-plane and out-of-plane spin configurations are defined by altering the magnetic anisotropy. These spin-engineered media not only maintain the surface planarity but also the homogeneity of the magnetic materials, and our method is likely to find immediate application on account of its simplicity and ease of integration.

Journal Article↗
PubMed2001

Flux closure structures in cobalt rings.

Measurements are reported on the magnetization reversal in submicron magnetic rings fabricated by high-resolution electron beam lithography and lift-off from cobalt thin films. For all dimensions investigated, with diameters of 300-800 nm and a thickness of 10-50 nm, the flux closure state is the stable magnetization configuration. However, with increasing diameter and decreasing film thickness a metastable near single domain state can be obtained during the reversal process in an in-plane applied field.

Journal Article↗
PubMed2000

Computation of the strain field generated by dislocations with a position-dependent Burgers' vector distribution

A new phenomenon of strain relaxation will be presented. In a series of InxGa1-xAs graded composition buffer layers grown on well cut (001) GaAs substrates, a curvature of the epilayer lattice has been found, i.e. a tilt of the epilayer lattice orientation with respect to the substrate which varies coherently along the sample surface on the scale of several mm. The most recent data analysis performed on a buffer layer compositionally graded with a six-step profile shows also a thickness functional dependence of the curvature. The epilayer lattice curvature has been attributed to a coherent lateral distribution of the Burgers' vectors. An analytical model has been developed in the framework of the continuum elasticity theory to compute the related strain field. The results show small but unexpected contributions to the parallel strain.

Journal Article↗
PubMed1998

Delapril slows the progression of atherosclerosis and maintains endothelial function in cholesterol-fed rabbits.

The renin-angiotensin system is an important modulator of arterial blood pressure and inhibitors of the angiotensin-converting enzyme (ACE-Is) and are currently used in the treatment of hypertension. The pleiotropic actions exerted by angiotensin II (AngII) on the functionality of the vessel wall may have pro-atherosclerotic outcomes; evidence for an anti-atherosclerotic effect of ACE-Is has been presented and an antioxidant effect has been attributed to thiol-containing ACE-Is, like Captopril. The present study has been undertaken to investigate the effect of Delapril, a lipophilic ACE-I, on the development of atherosclerosis in cholesterol-fed rabbits. While it did not correct hyperlipidemia, Delapril dose dependently inhibited the development of atherosclerosis, expressed as aortic area covered by lesions (23.3+/-4.1, 21.3+/-2.4 and 18.5+/-3.3% with Delapril at the daily dose of 5, 10 and 20 mg/kg, respectively, versus 38.2%+/-6.4 for control animals) and its effect was similar to that of Captopril (14.5+/-5.1% at the daily dose of 25 mg/kg). Furthermore, Delapril partially and dose dependently restored endothelium-dependent relaxation, which is impaired in vessels from hypercholesterolemic animals (51.80+/-12.18, 59.74+/-5.16, 69.13+/-8.70 maximal percent relaxation versus 48.26+/-3.05% for the untreated control and 67.67+/-6.72% for Captopril-treated animals). An antioxidant mechanism is unlikely to explain this data, since Delapril does not contain thiol groups. These observations suggest that Delapril may represent an effective pharmacological approach for the treatment of atherosclerosis during its early phases.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

Effect of lercanidipine and its (R)-enantiomer on atherosclerotic lesions induced in hypercholesterolemic rabbits.

The in vivo antiatherogenic activity of the calcium antagonist lercanidipine and its (R)-enantiomer was investigated in two different types of atherosclerotic lesions (hyperplastic and fatty-streak lesions) in rabbits. Lercanidipine (0.3, 1, and 3 mg kg(-1) week(-1)) as well as its (R)-enantiomer at 3 mg kg(-1) week(-1) were given by subcutaneous injection for 10 weeks to White New Zealand rabbits, with cholesterol feeding beginning at week 2. The hyperplastic lesion was obtained by positioning a hollow silastic collar around one carotid artery, while aortic fatty streak lesions were induced by cholesterol feeding. In untreated animals (n=5), 14 days after collar positioning an intimal hyperplasia was clearly detectable: the arteries without collar showed a intima/media (I/M) ratio of 0.03+/-0.02, whereas in carotids with a collar the ratio was 2+/-0.42. In lercanidipine-treated animals a significant and dose-dependent effect on intimal hyperplasia was observed. I/M ratios were 0.73+/-0.4, 0.42+/-0.1, 0.32+/-0.1 for 0.3, 1, and 3 mg kg(-1) week(-1), respectively (P<0.05). The lercanidipine enantiomer (3 mg kg(-1) week(-1)) was as effective as the racemate (0.41+/-0.11). Proliferation of smooth muscle cells, assessed by incorporation of BrdU into DNA, was reduced by about 50%, 70%, 85%, and 80% by lercanidipine (0.3, 1, and 3 mg kg(-1) week(-1)) and its (R)-enantiomer, respectively. The area of fatty-streaks in the aorta (n = 11-15) was significantly reduced by lercanidipine (3 mg kg(-1) week(-1), 16% vs 27%, P<0.05), a trend was observed also with lower doses. When different segments of the aorta were considered (arch, thoracic, abdominal) a significant and dose-dependent effect in the thoracic and abdominal aorta was observed also at lower doses. The (R)-enantiomer was as effective as lercanidipine. These results suggest a direct antiatherosclerotic effect of lercanidipine, independent of modulation of risk factors such as hypercholesterolemia and/or hypertension as demonstrated by the absence of stereoselectivity.

Animals↗
PubMed1996

Mitomycin C plus vindesine plus etoposide (MEV) versus mitomycin C plus vindesine plus cisplatin (MVP) in stage IV non-small-cell lung cancer: A phase III multicentre randomised trial. The "Gruppo Oncologico Centro-Sud-Isole' (G.O.C.S.I.).

PURPOSE: To compare mitomycin C plus vindesine plus etoposide (MEV) vs. mitomycin C plus vindesine plus cisplatin (MVP) in the treatment of stage IV non-small-cell lung cancer. PATIENTS AND METHODS: 204 patients were entered in a phase III multicentre randomised trial from June 1990 to December 1994 and stratified according to the ECOG performance status (0-1 vs. 2). MVP was given in the following dosages: mitomycin C 8 mg/m2+vindesine 3 mg/m2+cisplatin 100 mg/m2 i.v. day 1 and vindesine 3 mg/m2 i.v. day 8 with cycles repeated every 4 weeks. MEV was given in the following dosages: mitomycin C 8 mg/m2+vindesine 3 mg/ m2 i.v. day 1 and etoposide 100 mg/m2 i.v. days 1 to 3 with cycles repeated every 3 weeks. For both treatments a maximum of 6 cycles was planned. Response and toxicity were evaluated according to WHO. Subjective responses were assessed by numerical scales. Analyses were made on the basis of intent to treat. RESULTS: The objective response rate was 21.4% (1 CR + 21 PR among 103 patients) in the MEV and 28.7% (1 CR + 28 PR among 101 patients) in the MVP arm (P = 0.48). Symptoms were similar in the two arms. 196 patients progressed and 182 died. The median times to progression were 10 weeks (95% CI 9-12) and 12 weeks (95% CI 10-15) and median survivals were 29 weeks (95% CI 25-36) and 28 weeks (95% CI 25-35) in the MEV and MVP arms, respectively. The relative risks of progressing and of dying were 0.89 (95% CL 0.66-1.20) and 0.96 (95% CL 0.71-1.30), respectively, for patients receiving MVP as compared with those receiving MEV at multivariate analysis adjusted by sex, age, histologic type, number of metastatic sites, performance status at entry, and centre. CONCLUSIONS: In the present study, no significant differences were observed in response rate, survival or palliation of symptoms between the MEV and MVP regimens, while toxicity was significantly more frequent and severe with MVP. Thus, MEV should be considered a reasonable alternative to the MVP regimen in the treatment of stage IV NSCLC.

Adult↗
PubMed1993

Combined treatment with buserelin and cyproterone acetate in metastatic male breast cancer.

BACKGROUND: Male breast cancer (MBC) is considered an androgen-dependent tumor, and as in prostatic cancer, responses have been reported with use of antiandrogens or gonadotropin-releasing hormone analogs. Thus, it is reasonable to postulate that better results could be achieved by combining these two agents. METHODS: Eleven men with recurrent or progressive carcinoma of the breast have been treated with buserelin 1500 micrograms subcutaneously daily in the first week and 600 micrograms daily subsequently and cyproterone acetate (CPA) 100 mg twice a day orally starting 24 hours before the first dose of buserelin. RESULTS: Objective responses have been observed in seven patients with a median duration of 11.5 months (range, 9-24+ months). Responses were not correlated to the dominant site of disease. Three patients had stable disease lasting 5 months. Median survival was 18.5 months. Side effects primarily were decrease or loss of libido, impotence, and hot flushes. CONCLUSIONS: Total androgen blockade with buserelin and CPA seems effective in the treatment of patients with advanced cancer of the male breast, but its superiority over standard androgen suppression remains to be demonstrated.

Aged↗
PubMed1991

Combination chemotherapy with oral idarubicin and cyclophosphamide for metastatic breast cancer.

A group of 40 women with objectively measurable metastatic breast cancer was treated with idarubicin, 35 mg/m2 on day 1, and cyclophosphamide, 200 mg/m2 on days 2-5, both drugs being administered orally every 3 weeks. Of 37 evaluable patients, 4 (10.8%) achieved a complete response and 14 (37.8%) a partial response, for an overall response rate of 48.6% (95% confidence interval, 37.45%-59.75%). In previously untreated patients the response rate was 58.3%, whereas it was 44% in patients previously exposed to cytotoxic drugs. The median duration of response was 6.5 months, and the median survival of all patients was 10.5 months. Moderate nausea and vomiting were common. Diarrhoea, which occurred in 37% of the patients, was usually short-lived. Alopecia was generally mild, myelosuppression was the dose-limiting toxicity. Grade 3-4 leukopenia occurred only in pretreated patients. In previously untreated patients it was generally of grade 1-2. Laboratory evidence of cardiotoxicity (greater than or equal to 20% decrease in the left-ventricular ejection fraction from the baseline value) was observed in 3 out of 26 patients, who had at least two determinations of the left-ventricular ejection fraction, and was transient in nature. No cases of congestive heart failure were observed. These results indicate that the combination of idarubicin + cyclophosphamide represents a practical and effective regimen to be used in selected patients with advanced breast cancer.

Administration, Oral↗
PubMed1990

[Fluorouracil and high-dose folinic acid in the treatment of advanced colorectal carcinoma].

Forty-five consecutive patients with advanced colorectal cancer were treated with 5-fluorouracil and high dose folinic acid. Among 43 evaluable patients there were 7 objective responses for an overall response rate of 16%. Toxicity was generally mild and rapidly reversible. Compared to those reported with 5-fluorouracil alone, these results failed to demonstrate an increase in response rate in the treatment of advanced colorectal cancer with the combination of 5-fluorouracil and folinic acid.

Adult↗
PubMed1990

5-Fluorouracil, epirubicin, and BCNU (FEB) in advanced measurable gastric cancer.

Forty-eight patients with advanced measurable gastric cancer were treated with the three-drug combination of 5-fluorouracil, epirubicin, and BCNU (FEB). The response rate was 42% in 45 evaluable patients. There were five complete responders (11%). The median duration of response was 13 months, and the median survival of all patients was 9.2 months. Toxicity was generally mild to moderate. No instances of congestive heart failure were recorded. These results indicate that patients with metastatic gastric cancer can be effectively palliated with FEB chemotherapy.

Adenocarcinoma↗
PubMed1989

[Aztreonam and oxacillin in the treatment of febrile neutropenic patients with solid tumors].

22 consecutive febrile episodes in 21 neutropenic (PMN less than 1000/mmc) cancer patients, were treated with aztreonam and oxacillin. Nineteen patients were severely neutropenic (PMN less than 500/mmc). Cure was obtained in 86% of the febrile episodes, including 6/7 bacteriologically documented gram negative infections. No major side effects were observed. These results seem to indicate that aztreonam is effective as empiric treatment of gram negative infections in neutropenic patients. However, it must be used in combination with another antibiotic to ensure gram positive coverage.

Adult↗
PubMed1988

Phase III randomized study of fluorouracil, epirubicin, and cyclophosphamide v fluorouracil, doxorubicin, and cyclophosphamide in advanced breast cancer: an Italian multicentre trial.

From February 1983 to January 1985, 497 patients with advanced breast cancer were randomly allocated to receive either epirubicin or doxorubicin in the following combination chemotherapy regimen: fluorouracil (5-FU) 500 mg/m2 intravenous (IV) on days 1 and 8; epirubicin or doxorubicin 50 mg/m2 IV on day 1; cyclophosphamide 500 mg/m2 IV on day 1 (FEC or FAC). Cycles were repeated every 21 days until progression or to cumulative doses of 700 mg/m2 for epirubicin and 550 mg/m2 for doxorubicin. Dose reductions were applied according to the standard criteria. Activity was evaluated in 443 patients (222 in the FEC arm and 221 in the FAC arm). The two experimental groups were comparable in age, performance status, menopausal status, histology, previous treatments, and site of the disease. The overall response rate (complete response and partial response [CR + PR]) was not significantly different: 53.6% for FEC and 56.5% for FAC. The median time to progression was 273 days for FEC and 314 days for FAC; the median survival time was 591 and 613 days, respectively. Leukopenia, anemia, nausea, and vomiting were significantly lower in patients treated with FEC. As for cardiotoxicity, four cases of congestive heart failure (CHF) were recorded among patients treated with FAC while only one was observed in the FEC group. These results indicate that epirubicin in a combination chemotherapy regimen is as active as doxorubicin and is significantly less toxic.

Adult↗