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Biomedical subjects

C Carbone

Publications and source records attributed to C Carbone.

At least 19 recordsLinked to original sources
PubMed2003

Giant magnetic anisotropy of single cobalt atoms and nanoparticles.

The isotropic magnetic moment of a free atom is shown to develop giant magnetic anisotropy energy due to symmetry reduction at an atomically ordered surface. Single cobalt atoms deposited onto platinum (111) are found to have a magnetic anisotropy energy of 9 millielectron volts per atom arising from the combination of unquenched orbital moments (1.1 Bohr magnetons) and strong spin-orbit coupling induced by the platinum substrate. By assembling cobalt nanoparticles containing up to 40 atoms, the magnetic anisotropy energy is further shown to be dependent on single-atom coordination changes. These results confirm theoretical predictions and are of fundamental value to understanding how magnetic anisotropy develops in finite-sized magnetic particles.

Journal Article↗
PubMed2002

Finite temperature magnetism in Gd: evidence against a Stoner behavior.

The temperature dependence of the rare-earth valence bands has been regarded as a realization of the Stoner behavior. The exchange splitting of the electronic states appears to scale as the magnetic order parameter for T<T(C) and to vanish at T = T(C). We report here a spin-resolved photoemission study on the evolution of Gd bulk bands for 0.5< or =T/T(C)< or=1. The spin-polarized spectral line shapes display a complex temperature dependence, which clearly contrasts with the interpretation of previous experimental results. The spin-resolved photoemission data demonstrate the inadequacy of the Stoner model to the description of magnetism in rare earths.

Journal Article↗
PubMed2002

Ferromagnetism in one-dimensional monatomic metal chains.

Two-dimensional systems, such as ultrathin epitaxial films and superlattices, display magnetic properties distinct from bulk materials. A challenging aim of current research in magnetism is to explore structures of still lower dimensionality. As the dimensionality of a physical system is reduced, magnetic ordering tends to decrease as fluctuations become relatively more important. Spin lattice models predict that an infinite one-dimensional linear chain with short-range magnetic interactions spontaneously breaks up into segments with different orientation of the magnetization, thereby prohibiting long-range ferromagnetic order at a finite temperature. These models, however, do not take into account kinetic barriers to reaching equilibrium or interactions with the substrates that support the one-dimensional nanostructures. Here we demonstrate the existence of both short- and long-range ferromagnetic order for one-dimensional monatomic chains of Co constructed on a Pt substrate. We find evidence that the monatomic chains consist of thermally fluctuating segments of ferromagnetically coupled atoms which, below a threshold temperature, evolve into a ferromagnetic long-range-ordered state owing to the presence of anisotropy barriers. The Co chains are characterized by large localized orbital moments and correspondingly large magnetic anisotropy energies compared to two-dimensional films and bulk Co.

Journal Article↗
PubMed2002

Localized magnetic states of Fe, Co, and Ni impurities on alkali metal films.

X-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) have been used to study transition metal impurities on K and Na films. The multiplet structure of the XAS spectra indicates that Fe, Co, and Ni have localized atomic ground states with predominantly d7, d8, and d9 character, respectively. XMCD shows that the localized impurity states possess large, atomiclike, magnetic orbital moments that are progressively quenched as clusters are formed. Ni impurities on Na films are found to be nonmagnetic, with a strongly increased d10 character of the impurity state. The results show that the high magnetic moments of transition metals in alkali hosts originate from electron localization.

Journal Article↗
PubMed2002

[Integrated clinical record: unique document for diverse uses].

Technological and scientific development and changes in the health system have led to modifications and greater complexity in health documents and clinical records, without there being at the same time definition of guidelines on their correct compilation and formulation. The present study was designed to develop a single Integrated Clinical Record that combines, on the one hand, data of all medical, nursing and technical interventions and, on the other, involves the patient in all decisional processes of diagnosis and treatment during the hospitalization period. All phases of the project related to development of the Integrated Clinical Record are discussed. The data of 240 new clinical records regarding patients admitted consecutively over a period of 6 months are reported. The results show a progressive reduction of compilation errors and an improved management of the patient's clinical course. The innovative aspects of the new clinical record are discussed, with particular reference to the system of quality management, within which context the clinical record has to function, and to the modalities of check, audit and improvement.

Humans↗
PubMed2001

Electronic band structure of Gd: a consistent description.

The dispersion of the Gd (5d6s)-valence bands has been investigated by means of spin- and angle-resolved photoemission. The spin analysis of various spectral features shows that their weak dispersion and unusual broadening is due to the photoelectron lifetime rather than to correlation induced band narrowing as previously proposed. These results resolve a long-standing discrepancy between theoretical and experimental descriptions of the rare earth band structure.

Journal Article↗
PubMed2000

Mice vaccination with interleukin 12-transduced colon cancer cells potentiates rejection of syngeneic non-organ-related tumor cells.

Cell-based gene therapy after cytokine gene transfer is being investigated for autologous and allogeneic vaccination in cancer therapy. Here we show that mice vaccinated with 3-5 x 10(6) interleukin 12 (IL-12) gene-transduced CT26 colon cancer cells developed a long-lasting antitumor immune memory able to reject not only parental cells but also syngeneic, LM3 mammary, and MCE fibrosarcoma tumorigenic cells. In contrast, mice vaccinated with 0.5-1 x 10(6) CT26 cells transduced with pBabe neo IL-12 retrovirus cells (CT26-IL12) were only able to reject parental cells. An increase in the total circulating levels of IgG2a and a clear shift toward a systemic Th1 response developed, regardless of the amount of injected CT26-IL12 cells. On the contrary, a strong increase in anti-CT26-specific IgG2a levels was observed only when 3-5 x 10(6) CT26-IL12 cells were injected. Immunocompetent mice vaccinated with 3-5 x 10(6) CT26-IL12 cells developed local nodules for a few days, which then ceased growing. These nodules comprised mainly blood vessels, suggesting that an angiogenic process was taking place. CD8+ T cells were responsible for the anti-LM3 tumor cell memory, whereas CD4+ T cells were not involved. Splenocytes and lymphocytes obtained from mice immunized against CT26 cells were able to kill LM3 cells in vitro. Adoptive transfer of lymphocytes obtained from animals immunized against CT26 colon cancer cells suppressed LM3 mammary tumor growth in tumor-bearing mice. The present studies raised the possibility of isolating CTL clones and identifying CTL epitopes shared by different tumor cell types, which can be a target for cancer therapy.

Animals↗
PubMed2000

One-dimensional spin-polarized quantum-wire states in Au on Ni(110)

Au chain structures have been prepared on Ni(110). Au6 s,p-derived features in photoemission spectra are identified as quantum-wire states due to their strong dispersion along the chains and absence of dispersion perpendicular to the chains in agreement with our ab initio calculation of the electronic structure. Spin analysis reveals that the states have minority-spin character showing that the confinement of electrons in the chain structure depends on the electron spin.

Journal Article↗
PubMed2000

Expression of allograft inflammatory factor-1 is a marker of activated human vascular smooth muscle cells and arterial injury.

The cytokine-induced activation and proliferation of medial vascular smooth muscle cells (VSMCs) leading to intimal hyperplasia is one of the most critical cellular events in the formation of transplant arteriopathy and balloon angioplasty-induced restenosis. Allograft inflammatory factor-1 (AIF-1) is a calcium-binding protein that we have previously shown to be expressed in balloon angioplasty-injured rat carotid arteries. We hypothesized that AIF-1 expression may be associated with the VSMC response to injury. In this study, we examined AIF-1 expression in immunologic and mechanical models of arterial injury. Reverse transcription-polymerase chain reaction and Western analysis demonstrated that AIF-1 is acutely and transiently expressed in aortic medial smooth muscle cells of rat cardiac allografts, with mRNA and protein peaking at 3 to 7 days after transplant and declining by 10 days after transplant. Immunohistochemical analysis identified abundant AIF-1 in the medial VSMCs of these vessels. Immunohistochemical analysis of balloon angioplasty-injured swine coronary arteries also demonstrates an acute AIF-1 expression detectable by 24 hours and continuing up to 14 days after the procedure. AIF-1 in these vessels also localizes to the medial VSMCs and cells of the developing neointima. AIF-1 protein is not expressed in quiescent cultured human VSMCs but is induced in cells challenged with various inflammatory cytokines, primarily by interferon-gamma, interleukin-1beta, and T-cell-conditioned media. Transfection and overexpression of AIF-1 in human VSMCs result in enhanced growth of these cells. Taken together, these data indicate that AIF-1 expression is associated with vascular trauma and suggest that this protein may play a role in VSMC activation subsequent to arterial injury.

Amino Acid Sequence↗
PubMed1999

Energetic constraints on the diet of terrestrial carnivores.

Species in the mammalian order Carnivora exhibit a huge diversity of life histories with body sizes spanning more than three orders of magnitude. Despite this diversity, most terrestrial carnivores can be classified as either feeding on invertebrates and small vertebrates or on large vertebrates. Small carnivores feed predominantly on invertebrates probably because they are a superabundant resource (sometimes 90% of animal biomass); however, intake rates of invertebrate feeders are low, about one tenth of those of vertebrate feeders. Although small carnivores can subsist on this diet because of low absolute energy requirements, invertebrate feeding appears to be unsustainable for larger carnivores. Here we show, by reviewing the most common live prey in carnivore diets, that there is a striking transition from feeding on small prey (less than half of predator mass) to large prey (near predator mass), occurring at predator masses of 21.5-25 kg. We test the hypothesis that this dichotomy is the consequence of mass-related energetic requirements and we determine the predicted maximum mass that an invertebrate diet can sustain. Using a simple energetic model and known invertebrate intake rates, we predict a maximum sustainable mass of 21.5 kg, which matches the point where predators shift from small to large prey.

Animals↗
PubMed1999

3-Hydroxy-3-methylglutaryl coenzyme a reductase activity in liver of athymic mice with or without an implanted human carcinoma.

Hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase activities and cholesterol content in the liver of athymic mice either bearing or not an implanted human lung mucoepidormoid carcinoma (HLMC) and in the neoplasic tissue, were analyzed. The properties of the HMG-CoA reductase of HLMC grown in nude mice and those ones found in the liver of these animals, sacrificed either at mid-light or mid-dark, were similar. The hepatic reductase activity was found to be four- to five-fold greater at mid-dark than at mid-light (462 +/- 141 vs. 123 +/- 22 pmol min-1 mg protein-1). Since the Km value was not modified, the mid-dark activity could be due to an increase in the amount of enzyme. In contrast, HLMC reductase activity and cholesterol content showed similar values at mid-light and mid-dark points. HLMC reductase does not appear to have any diurnal variation and the cholesterol synthesis and content seems to be independent of food intake. HLMC-bearing nude mice undergo several alterations in the biosynthesis and homeostasis of cholesterol. Hypocholesterolemia, lower hepatic cholesterol content and higher HMG-CoA reductase activity are characteristic of host mice.

Animals↗
PubMed1999

IL-10 expression by CT26 colon carcinoma cells inhibits their malignant phenotype and induces a T cell-mediated tumor rejection in the context of a systemic Th2 response.

In spite of the evidence that IL-10 has Th1-immunosuppressive and anti-inflammatory effects, it has been shown that IL-10 may reduce the tumorigenic capacity of certain tumor cell types. In order to characterize the responses elicited by IL-10, we explored the effect of transducing murine CT26 colon carcinoma cells with a recombinant retrovirus expressing mIL-10. IL-10 gene transfer of CT26 cells had no effect on tumor cell growth on plastic surface but inhibited the anchorage-independent growth capacity of tumor cells and their metastatic potential as assessed by their invasive and migration ability. Expression of IL-10 also elicited an antitumor immune response involving both CD4+ and CD8+ T cells. Assessment of the immune status of the animals demonstrated that mice injected with CT26-IL10 cells showed prevalence of a systemic and tumor-specific Th2 response. Spleen cells obtained from these mice showed an increased production of IL-4 and no changes in IFNgamma levels, characteristic of a Th2 response. These results demonstrate that IL-10 affects CT26 tumor cell growth by both inhibiting the malignant phenotype and by recruiting and activating a T cell-mediated antitumor response. This T cell response occurs in the context of a shift towards a Th2 response.

Analysis of Variance↗
PubMed1997

Anthropometric features in infants of mothers with gestational diabetes: relationship with treatment modalities.

We compared the effects of two treatment strategies (diet alone versus a combination of insulin and diet) on neonatal anthropometric measurements and the outcome of a full-term white infant sample born to mothers with gestational diabetes mellitus (GDM). Study subjects included 217 consecutive nonrandomized women with GDM with term singleton pregnancies. Insulin therapy was administered on the basis of anamnestic and maternal-fetal criteria. One hundred and twenty-one patients (group 1) received a combination of insulin and diet, and 96 (group 2) underwent diet alone. All 1,052 white patients with term singleton pregnancies without GDM, screened at the same time as the study group, formed the control group. The incidence of large-for-gestational-age (LGA) infants was significantly higher in group 2 (18.8%) compared with group 1 (9.9%) and the control group (8.3%). Male and female infants born to diabetic mothers of group 2 had significantly greater mean birth weights, ponderal indices, thoracic circumferences, weight/length ratios and significantly smaller mean cranial/thoracic circumference ratios than male and female infants in group 1 and the control group (p < 0.05, Scheffe test). Treatment of GDM mothers with insulin and diet has been shown to be able not only to normalize the incidence of LGA infants but also to influence the anthropometric characteristics of the infants born to these mothers to such an extent that they showed no significant differences compared to infants born to non-diabetic mothers.

Adult↗
PubMed1997

Peptic ulcer in patients with liver cirrhosis: a retrospective endoscopic and clinical study.

AIM: It has been showed that peptic ulcer is more frequent in patients with liver cirrhosis, is associated with the severity of cirrhosis, and occurs without upper abdominal pain in up to 70% of patients and with complications in 29%. The aim of this study was to retrospectively assess the characteristics of peptic ulcer in a large series of patients with liver cirrhosis. MATERIALS AND METHODS: In this retrospective study the consecutive records of 1,748 endoscopies, performed in patients with liver cirrhosis during a period of 14 years, were reviewed to evaluate the frequency and clinical characteristics of peptic ulcer. RESULTS: The ulcer prevalence was 6.3%, and 77.5% of the ulcers were asymptomatic. Complications from ulcer were present in 29% of all patients and in 32% of those who has the first diagnosis of ulcer during the study. Patients with asymptomatic ulcer had a more decompensated cirrhosis. After healing, 20%-25% of the recurrent ulcers had complications while patients were on standard maintenance treatment. CONCLUSIONS: This retrospective study confirms the high frequency of peptic ulcer in patients with liver cirrhosis. It also confirms that the peptic ulcer in these patients is very often asymptomatic and associated with concurrent complications, especially in those with more severe liver disease. The complication rate in recurrent ulcers was 20%-25%. However, due to the retrospective nature of this study, after ulcer healing the endoscopic follow-up was irregular. Regularly repeated endoscopy should be carried out in patients with liver cirrhosis and peptic ulcer to diagnose new and recurrent ulcers and to prevent related complications.

Female↗