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S Colombi

Publications and source records attributed to S Colombi.

At least 19 recordsLinked to original sources
PubMed2004

Churg-Strauss syndrome associated with the leukotriene antagonist montelukast.

Churg-Strauss syndrome (CSS) is a disseminated small vessel vasculitis characterized by late-onset asthma, upper airways disease, eosinophilia and late neurological manifestations such as peripheral neuropathy. Recently, several cases of CSS have been reported in patients treated with leukotriene antagonists after weaning corticosteroids. We describe a case of CSS developed while the patient was receiving montelukast for asthma treatment, after corticosteroids withdrawal. A causal relationship between montelukast therapy and CSS is hypothesized.

Acetates↗
PubMed2000

Tree structure of a percolating Universe.

We present a numerical study of topological descriptors of initially Gaussian and scale-free density perturbations evolving via gravitational instability in an expanding Universe. The measured Euler number of the excursion set at the percolation threshold, delta(c), is positive and nearly equal to the number of isolated components, suggesting that these structures are trees. Our study of critical point counts reconciles the clumpy appearance of the density field at delta(c) with measured filamentary local curvature. In the Gaussian limit, we measure delta(c)>sigma, where sigma2 is the variance of the density field.

Journal Article↗
PubMed1998

CD28-B7 costimulatory blockade by CTLA4Ig delays the development of retrovirus-induced murine AIDS.

Mouse AIDS (MAIDS) induced in C57BL/6 mice by infection with a replication-defective retrovirus (Du5H) combines extensive lymphoproliferation and profound immunodeficiency. Although B cells are the main target of viral infection, recent research has focused on CD4(+) T cells, the activation of which is a key event in MAIDS induction and progression. A preliminary observation of increased expression of B7 molecules on B cells in MAIDS prompted us to address the possible involvement of the CD28/B7 costimulatory pathway in MAIDS. Mice infected with the MAIDS-inducing viral preparation were treated with murine fusion protein CTLA4Ig (3 x 50 microg/week given intraperitoneally), a competitive inhibitor of physiological CD28-B7 interactions. In CTLA4Ig-treated animals, the onset of the disease was delayed, lymphoproliferation progressed at a much slower rate than in untreated mice, and the loss of in vitro responsiveness to mitogens was reduced. Relative expression of Du5H did not differ between treated and untreated animals. These results suggest that the CD28/B7 costimulatory pathway contributes to MAIDS development.

Abatacept↗
PubMed1997

Peyer's patches in murine AIDS: dissociation between lymphoproliferation and anergy.

RadLV-Rs infection induces a murine immunodeficiency syndrome associated with a dramatic enlargement of spleen and lymph nodes. Surprisingly, the lymphoproliferation excludes thymus and Peyer's patches (PP). To understand the cellular interactions underlying lymphoproliferation further, the authors investigated the fate of PP in RadLV-Rs infected mice. The atrophy of PP was mostly due to the depletion of B cells, while the proportion of CD4+ and CD8+ T cells was increased. Nevertheless, B cell phenotype was modified with the emergence of lymphocytes with a low expression of B220 in infected PP. T cells characterized by a memory/activated phenotype in control PP did not undergo phenotypical changes after viral infection (i.e. regarding Thy-1 and CD44 expression). Despite the absence of lymphoproliferation, PP T and B cells displayed altered responses to mitogens in vitro. Finally, alterations of the expression of adhesion molecules and vascular addressins could not explain the atrophy of PP by a reduced homing to this lymphoid site. B cells and T cells from normal PP are clearly different from lymph nodes (LN) lymphocytes. The authors propose that the particular functional state which characterizes PP lymphocytes influences the B cell/T cell crosstalk necessary for RadLV-Rs-induced lymphoproliferation.

Animals↗
PubMed1996

Subset-specific analysis of calcium fluxes in murine AIDS.

Infection of susceptible strains of mice with the Duplan strain of murine leukemia viruses induces a syndrome called MAIDS (murine acquired immunodeficiency syndrome) characterized by immunodeficiency and lymphoproliferation. In addition to a complete refractoriness of most subsets of lymphocytes to mitogen stimulation, the development of phenotypic abnormalities occurs such as the appearance of an abnormal CD4+ T cell subset lacking membranes Thy-1. This study was performed to compare the calcium responses during the early stages of MAIDS (week 9 or earlier) between T cells and B cells and between CD4+Thy-1- and CD4+Thy-1+ T cells. B cells were strikingly less affected than T cells: their baseline [Ca2+]i did not significantly increase, and their calcium response to anti-IgM antibody and concanavalin A (Con A) was partially maintained. In contrast, the response to Con A was completely abolished in T cells. Interestingly, calcium mobilization in response to membrane receptor-independent stimuli such as ionophores and thapsigargin was strongly inhibited in T cells, while no such inhibition was found in B cells. In comparison with their CD4+Thy-1+ counterparts, CD4+Thy-1- T cells had blunted calcium responses in controls, as well as in infected mice. However, CD4+Thy-1+ T cells were also strikingly altered, suggesting that the loss of membrane Thy-1 could be associated with, but not directly responsible for abnormalities of calcium responses in CD4+ T cells from RadLV-Rs-infected mice.

Animals↗
PubMed1995

A comparison of two GM-CSF schedules to counteract the granulo-monocytopenia of carboplatin-etoposide chemotherapy.

In order to obtain the beneficial effects from granulocyte-macrophage colony-stimulating factor (GM-CSF) on granulo-monocyte recovery with the minimum dose and toxicity, we compared the effect of two different GM-CSF schedules (5 micrograms/kg/day subcutaneously, days 5 to > 18 versus days 12 to > 18 on the cytopenias which follow cytostatic treatment with carboplatin (400 mg/m2 intravenous (i.v.) day 1) and etoposide (100 mg/m2 i.v. days 1 to > 3). 13 patients entered the study for a total of 36 evaluable cycles. The cytostatic treatment produced a neutropenia that persisted for up to day 22 (absolute neutrophil count (ANC) < 1000/microliters in 25% and ANC < 2000 in 50% of control cycles). Early GM-CSF administration markedly increased the leucocyte nadir and produced two waves of leucocytosis: an early one, linked to marrow reserve release and presumably of no value to the patients; and a delayed one, due to marrow precursor and progenitor cell proliferation, in which the granulomonocytosis was associated with a marked eosinophilia. The delayed GM-CSF administration markedly increased the leucocyte nadir and accelerated granulo-monocyte recovery (with an only modest eosinophilia), so that chemotherapy could be repeated every 21 days in all the patients.

Adult↗
PubMed1995

Morphological changes of thymus in retrovirus-induced murine acquired immunodeficiency syndrome (MAIDS).

The possible contribution of the thymus in the setting of acquired immunodeficiencies is still questioned. Here we report some new findings regarding a potential involvement of the thymus in mice infected with RadLV-Rs, a viral mixture inducing murine acquired immunodeficiency syndrome (MAIDS). Thymi were sequentially removed, weighted and morphologically analyzed at different time intervals post-infection. Infection with RadLV-Rs led to a decrease in thymus weight mostly apparent from the fourth week. The first changes were seen at the third week as perivascular clusters of B-cells at the cortico-medullary junction. The ensuing process of atrophy mainly involved the cortex, while a mixed population of large T- and B-cells filled the medulla. These observations are discussed with regard to the pathological changes occurring in other lymphoid and non-lymphoid organs, in the context of the lymphoproliferation and immunodeficiency characterizing the disease, and by comparison with other models of retrovirus-induced immunodeficiencies.

Animals↗
PubMed1995

Fractionation of an antiserum to progesterone by affinity chromatography: effect of pH, solvents and biospecific adsorbents.

Several progesterone-AH Sepharose 4B matrices were prepared as biospecific adsorbents suitable for affinity chromatography to fractionate antibodies of different affinity and specificity from a polyclonal antiserum to progesterone-11 alpha-hemisuccinate-BSA. From an affinity column of progesterone-11 alpha-hemisuccinate-AH Sepharose 4B no antibodies can be eluted, even with glycine buffer (pH 2.6) and 30% of 2-methoxyethanol. The use of biospecific adsorbents, prepared by coupling with AH Sepharose 4B progesterone derivatives [5-pregnene-3,20-dione di(ethyleneacetal)-11 alpha-ol-11 alpha-hemisuccinate; 4-pregnene-11,20 beta-diol-3-one-11 alpha-hemisuccinate 20 beta-benzoate; progesterone-3-carboxymethyloxime] having a low cross-reactivity with the antiserum, makes the elution of various antibody fractions of variable affinity and specificity possible. 2-Methoxyethanol or N,N-dimethylformamide gradients, in acetate or TRIS buffer, were equally efficient for fractionating the antiprogesterone serum, while a decreasing pH gradient was less effective and eluted antibody fractions that were further separated into various binding components by a solvent gradient. Antibodies eluted from the affinity columns by an eluent containing a high solvent concentration have affinities higher than antibodies eluted at lower solvent concentration.

Absorption↗
PubMed1994

Population dynamics of CD4+ T cells lacking Thy-1 in murine retrovirus-induced immunodeficiency syndrome (MAIDS).

Increased numbers of CD4+ Thy-1- cells have been described in the spleen (SP) of mice with retrovirus-induced immunodeficiency (MAIDS). Since this phenotypic abnormality might have considerable functional importance, the expansion of the CD4+ Thy-1- subset in MAIDS was characterized further. CD4+ Thy-1- and Thy-1+ T-cells from infected mice expressed similar densities of CD3 and TCR alpha/beta. In contrast, the Thy-1- subset was uniformly CD44hi, even early in the disease when part of Thy-1+ cells were still CD44lo. The emergence of CD4+ Thy-1- cells occurred first in SP and lymph nodes and was observed later in thymus. The important fraction of CD4+ cells lacking Thy-1 normally present in Peyer's patches was only weakly modified. Despite the major expansion of the CD4+ Thy-1- phenotype, the proliferating fraction was not higher in this subset than in CD4+ Thy-1+ cells from infected mice. Persistence after hydroxyurea administration was identical in both subsets, indicating similar mean cell lifespans. Taken together, these results show that the major expansion of CD4+ Thy-1- T-cells in MAIDS is not ascribable solely to increased proliferation within this subset. Phenotypic analysis suggests that CD4+ Thy-1- cells result from the differentiation of Thy-1+ cells induced by activation signals related to retroviral infection.

Animals↗
PubMed1994

Thymus involvement in murine acquired immunodeficiency (MAIDS).

Due to self-renewal of the peripheral pool of T-cells, adult thymectomy has normally little influence on immunocompetence. However, thymus might play a more important role in the setting of viral-induced cytopathic effects on T-cells in the periphery. Therefore, thymus weight, cell numbers, and subset distribution were sequentially analysed after infection with RadLV-Rs, a viral mixture known to induce murine retrovirus induced immunodeficiency (MAIDS). Infection induced thymic atrophy (concerning organ weight as well as total cell number) which culminated seven weeks after inoculation. The atrophic process mostly reflected the depletion of double positive CD4+ CD8+ cells since their proportion sharply decreased around week 6. Single positive T-cells were less affected by the process. The proportion of B-cells progressively increased. Surprisingly, there was a strong correlation between the extent of atrophy and the frequency of B-cells in the thymus. Finally, an abnormal CD4+ T-cell subset lacking Thy-1 and previously described in the periphery also appeared in the thymus and its frequency was strongly correlated with the expansion of B-cells in this organ.

Animals↗
PubMed1988

[Reactions caused by Hymenoptera: a first aid problem].

The incidence of reactions to insect bites both local (erythema, pemphigus, oedema, itching) and systemic (urticaria, angioedema, anaphylactic shock) in Borgomanero (NO) National Health Clinic 54 was assessed. The high incidence of medical treatments for this pathology encountered reflects the fact that in the summer and in a rural area a great many people are exposed to this type of emergency. The importance of careful diagnosis (anamnesis, skin allergy tests, RAST is emphasised as a means of identifying cases at allergic risk and providing the appropriate immunotherapy.

Animals↗
PubMed1987

[Contact sensitization in eczema of the hands].

A personal series of patients with eczema on the hands arising in non-occupational conditions was examined (students, housewives, clerical workers, teachers, farm labourers). The data obtained indicate the presence of allergic sensitisation in 70% of the cases and especially among females (3 : 1). The most frequently encountered allergens were difenylguanadine (used in rubber manufacture) and nickel. It is therefore suggested that patch tests should be performed immediately on these patients so that contact with allergen can be prevented in addition to the usual topical treatment.

Adolescent↗
PubMed1986

[Study of hypophyseal and gonadal hormones and cases of postmenopausal occurrence of bronchial asthma].

A study was conducted into the hormone profile of women with no previous history of allergy who developed bronchial asthma after menopause in order to discover any differences between these and patients of a similar age with allergic bronchial asthma. The serum levels of the following hypophyseal and gonadal hormones were therefore analysed: luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL), 17 oestradiol (17BE2) in both groups of patients and in a control group of healthy postmenopausal volunteers. The results showed lower FSH and LH and higher 17B7(2) levels in the patients with bronchial asthma but no clinical history of allergy than in either the patients with allergic asthma or the healthy volunteers. When the hormone picture in some of the group 1 patients normalised, the clinical symptoms disappeared. One possible explanation is the following: excess oestrogen in the "non-allergy" patients might have caused an imbalance in the PgF/PgE ratio which is thought to contribute to the regulation of bronchomotor tone. The same phenomena might also have accelerated the release of arachidonic acid and its metabolites.

Age Factors↗
PubMed1984

[Clinical considerations on a case of Caroli disease].

A case of Caroli's disease is presented. Stress is laid on the importance of transcutaneous cholangiography in the diagnosis of this morbid form, and the usefulness of both echotomography and computed tomography. The latter permits visualisation of the intra- and extrahepatic bile ducts and indicates the extent of the disease. At the same time, it permits evaluation of any alterations of other organs. Attention is also drawn to the importance of careful diagnostic employment of these means of investigation. Emphasis is equally placed on the way complications can be prevented through medical and surgical management.

Bile Ducts, Intrahepatic↗
PubMedDate not supplied

Two new fluorescent derivatives of progesterone to use in fluoroimmunoassay.

Synthesis, fluorometric and immunological properties of two new fluorescent derivatives of progesterone are reported. Both compounds were obtained from 11 alpha-hydroxyprogesterone 11-hemisuccinate; the fluorescent molecules were joined to the steroid by bifunctional arms. The first of these is cysteamine whose thiol group was reacted with N-(3-fluoranthenyl) maleimide, and the second is tyramine whose phenolic group was reacted with 1-nitroso-2 naphthol.

Cross Reactions↗