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Biomedical subjects

C Fioretti

Publications and source records attributed to C Fioretti.

14 recordsLinked to original sources
PubMed2005

Semiparametric animal models via penalized splines as alternatives to models with contemporary groups.

Contemporary groups (CG) are used in genetic evaluation to account for systematic environmental effects of management, nutritional level, or any other differentially expressed group effect; however, because the functional form of the distribution of those effects is unknown, CG serve as an approximation to a time-varying mean. Conversely, in semiparametric models, there is no need to assume any functional form for the time-varying effects. In this research, we present a semiparametric animal model (AMS) using the covariate day of birth (DOB) by means of penalized splines (P-splines), as an alternative to fitting CG. In the AMS, the functionality of the data on DOB is expressed by means of a Basic segmented polynomial line (B-spline) basis, and proper covariance matrices are used to reflect the serial correlation among the points of support (or knots) at different times. Three different covariance matrices that reflect either short- or long-range dependences among knots are discussed. Different models were fitted to birth weight data from Polled Hereford calves. Models compared were an animal model with CG, an animal model with CG and the covariate DOB nested within CG (CG + DOB), and P-splines with the first difference penalty matrix and three different AMS with 20, 40, 60, 80, or 120 knots. Models were compared using a modified Akaike information criterion (AICC), which was calculated as a byproduct of the estimation of variance components by REML using the expectation maximization algorithm. All three AMS had smaller (better) values of AICC than the regular model with CG, while producing almost the same ranking of predicted breeding values and similar average predicted error variance. In all AMS, the inference and all measures of comparison were similar when the number of knots was equal > or = 40. The model CG + DOB had analogous performance to the AMS, but at the expense of using more parameters. It is concluded that the use of penalized regression splines using a B-spline basis with proper covariance matrices is a competitive method to the fitting of CG into animal models for genetic evaluation, without having to assume any functional form for the covariate DOB.

Animals↗
PubMed2001

Characteristics of cerebral microembolism during carotid stenting and angioplasty alone.

BACKGROUND: Cerebral microembolism has often been documented by transcranial Doppler imaging during carotid angioplasty and stenting. However, few data are available about its characteristics during the 2 different kinds of procedure. OBJECTIVES: To compare the incidence of microemboli occurring during angioplasty alone with that during stenting in the different phases of the procedures and to relate it to periprocedural cerebrovascular complications. PATIENTS AND METHODS: Thirty-eight patients underwent 41 procedures (15 angioplasty alone and 26 stenting) for symptomatic carotid stenoses of 70% or more. Transcranial Doppler monitoring was performed to detect microemboli in the middle cerebral artery during 3 phases of the procedure: (1) guidewire crossing, (2) first dilatation in case of angioplasty alone or stent release with predilatation if performed, and (3) further dilatation. RESULTS: Microemboli occurred in all cases in phase 1 of the procedure but less frequently in the arteries treated with stenting when compared with those treated with angioplasty alone in phase 2 and particularly (P<.02) in phase 3. The mean number of microemboli was highest in phase 2, predominant (P<.05) during angioplasty alone, and particularly reduced (P<.02) in phase 3 during the stenting procedures. During 2 (5%) of the 41 procedures, cerebrovascular complications occurred in phase 1, with the number of microemboli being higher than mean values. CONCLUSIONS: Cerebral microembolism is a very common event, especially during guidewire crossing and angioplasty alone compared with stenting. Further studies concerning the prognostic significance of this are advisable.

Aged↗
PubMed1998

Bilateral medial frontal infarction in a case of azygous anterior cerebral artery stenosis.

We describe the unusual case of a 63-year-old woman with a history of arterial hypertension who presented a sudden weakness of the lower limbs followed by mutism, akinesia and dyspraxia. Magnetic resonance images showed a bilateral medial frontal infarction. Digital subtraction angiography documented a right azygous anterior cerebral artery with severe stenosis in its sub-callosal tract; the left anterior cerebral artery showed mild hypoplasia with only sub-frontal and fronto-polar branches. No embolic source was documented. Afterwards the patient presented a gradual and partial recovery of both motor and cognitive functions.

Angiography, Digital Subtraction↗
PubMed1998

Factor V Leiden mutation in a case with ischemic stroke: which relationship? A case report.

A 50-year-old man presented spontaneous internal carotid artery dissection with ischemic stroke. He had a history of deep venous thrombosis, and an activated protein C resistance due to factor V Leiden mutation was documented. He showed no other vascular risk factor. This unusual case puts the question whether this coagulation defect may be related to the stroke occurrence.

Aortic Dissection↗
PubMed1996

T-lymphocyte immunointerferon receptors in patients with multiple sclerosis.

Multiple sclerosis (MS) is a T-cell-mediated autoimmune demyelinating disease of the central nervous system (CNS), associated with an altered immunoregulation. Interferon (IFN)-gamma, also known as immune IFN, is a cytokine with several effects on the immune system. Specific IFN-gamma receptors have been found on human lymphocytes, as well as on other cell types (e.g. gliocytes), even in the CNS. The aim of the present study was to evaluate IFN-gamma binding on peripheral blood T-lymphocytes from MS patients, compared with those from healthy subjects. Thirty-two patients were selected according to the classical criteria for definite MS; as controls, 21 healthy subjects were studied. We have found that T-lymphocytes from MS patients bear a significantly smaller amount of IFN-gamma receptors than those from controls [Bmax: 568, 18 vs 708, 14 (mean, SE) receptors/ cell]. Such IFN-gamma binding sites are of the same type in patients and healthy subjects [Kd: 1.0, 0.05 vs 0.9, 0.02 (mean, SE) nM]. These findings are discussed in terms of immunopathogenesis of MS, since it has been reported that activated T-lymphocytes have decreased amounts of IFN-gamma receptors.

Adult↗
PubMed1996

Lymphocyte subsets in multiple sclerosis. A study with two-colour fluorescence analysis.

Multiple sclerosis (MS) is postulated to be an immunopathologically mediated disease. This concept is supported by the finding of abnormally distributed peripheral blood T-cell subsets and a decreased T-suppressor function. Thirty-seven MS patients have been selected according to the criteria for definite MS. Fluorescein- or phycoerythrin-conjugated monoclonal antibodies have been used to define different lymphocyte subsets: CD4+, CD5+, CD8+, CD19+, CD38+, CD45RA+, CD4+CD45RA+, CD19+CD5+, CD8+CD38+. In relapsing-remitting (RR)-MS patients a significantly decreased percentage of CD19+ cells and in progressive MS patients a significantly increased percentage of CD19+CD5+ cells have been found. During a relapse in RR-MS, a significantly decreased percentage of CD4+CD45RA+ cells and a significantly increased percentage of CD8+CD38+ cells have been observed. Moreover, in RR-MS patients a significantly increased percentage of CD38+ cells and significantly high IgM amounts have been found. The increased percentage of CD19+CD5+ and CD38+ cells (together with high IgM levels) and the reduced percentage of CD4+CD45RA+ lymphocytes could be related to an activation of both cellular and humoral immune response in acute MS.

Adolescent↗
PubMed1993

Screening for breast cancer: report of a population-based experience in the city of Milan, Italy.

AIMS AND BACKGROUND: Mammographic screening is recommended as a current health practice. The aim of the present study is to report the results of a new program which started in the city of Milan in 1989. METHODS: A total of 4882 women aged 50 to 61 years and resident in quarter no. 16 of Milan were invited by mail to attend the screening at the San Paolo Hospital based on two-view mammography and physical examination. RESULTS: A total of 2953 (60.5%) women attended the first screening round, and 18 cancers were detected (1 Tis, 8 T1, 9 T2). The detection rate was 6.9 x 1000, and the prevalence/incidence ratio was around 3.5. CONCLUSIONS: The study confirms the feasibility of breast cancer screening in an urban setting by using the existing general hospital facilities and should be considered as a possible model for other urban experiences.

Aged↗
PubMed1989

Vidian nerve resection, histamine turnover and mucosal mast cell function in patients with chronic hypertrophic non-allergic rhinitis.

Parasympathetic innervation of the respiratory tract of nasal mucosa plays an important role in the pathogenesis of chronic hypertrophic non-allergic rhinitis (C.H.N.A.R.), the vidian nerve providing the main parasympathetic nerve supply to respiratory mucosa. The present study investigates the effect of vidian nerve resection in 22 patient with intractable C.H.N.A.R. on histamine content and formation and on the number of mast cells and their degranulation in the respiratory tract. Samples were taken from respiratory mucosa for histamine and histidine-decarboxylase assay, and for microscopic observations for mast cell density and degranulation index, before and 12-24 months after vidian nerve resection. Neurectomy of the vidian nerve completely cured the clinical symptomatology, evaluated by rhinoreomanometry, and also significantly decreased both the high histamine levels and histidine-decarboxylase activity in patients with C.H.N.A.R. The density and degranulation index of mast cells were also significantly lower after surgery. These data suggest a relationship between cholinergic activity and the secretory response of mast cells and indicates a correlation between the parasympathetic nerve supply and chronic hyperthrophic non-allergic rhinitis. The significant reduction in mast cell density, histamine levels and histidine-decarboxylase activity also lends support to the hypothesis that the parasympathetic nerve supply plays a role in the regulation of mast cell histamine.

Adolescent↗