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Biomedical subjects

A Balducci

Publications and source records attributed to A Balducci.

At least 19 recordsLinked to original sources
PubMed2006

Cardiac calcifications in hemodialysis patients assessed with spiral computed tomography.

AIM: Cardiac disease is a major cause of mortality in uremic patients. The aim of this paper was to evaluate cardiac calcium content in uremic patients with multislice computed tomography (MSCT). METHODS: The study has been carried out on 120 uremic and 28 nonuremic patients affected by cardiovascular disease. Serum calcium, phosphorus, calcium-phosphate product, intact PTH were assayed. Several lipidic and nutritional parameters were measured. Calcification values obtained with the MSCT were reported in terms of Agatson scores. RESULTS: We found that the average score values in cohort on uremic was 10 times higher than in nonuremic patients (score values 3.389 vs 328). Cardiac calcification score was found to be correlated significantly to age (P=0.006), HD age (P=0.010), serum calcium (P=0.006), iPTH (P=0.004). Multiregression analysis (MRA) with the cardiac score as dependent variable selected the following variables (R(2) 0.612): age (P=0.002), HD age (P=0.010), serum cholesterol (P<0.000), triglycerides (P=0.001) and inversely HDL cholesterol (P=0.001) and non-HDL cholesterol (P=0.001) as predictive variables for cardiac score. By comparing patients with scores lower and higher than 400, the group with score <400 showed a significantly lower age (P=0.0001), HD vintage (P=0.01) and a significantly higher serum cholesterol (P=0.009), HDL cholesterol (P=0.05) and non-HDL cholesterol (P=0.05). CONCLUSIONS: The MSCT could help in identifying and stratifying high-risk patients to implement preventive strategies. The control of mineral metabolism and of lipid levels is important in prevention of arterial calcification in uremic patients.

Calcinosis↗
PubMed2004

Proposal for a quantitative description of blood spiral flow in medical devices.

The association between specific blood flow patterns and blood behaviour through medical devices suggests that a Lagrangian study may be a useful instrument for the evaluation of the thrombogenic and/or hemolytic potential of certain devices' geometries and biomaterials. In this study a description of blood particle trajectories in terms of their spiral contents is proposed; such a mathematical description for blood spiral flow, computed along several pathlines, is tested for a quantitative determination of the spiralled motion of blood flow into two three-dimensional numerical models, having different design characteristics, of venous cannula inserted in a vessel. As the influence of vortical flow conditions have been observed to have both beneficial and detrimental influence on blood behaviour in terms of blood-device interaction, of the degradation of its components, and of the efficiency of mass-exchange (in red cells oxygenation and plasma filtration, for example), the herein proposed method for the description of spiral laminar motion may be a helpful instrument to build up a tool to investigate, for example, the existence of correlations between level of spiral flow and geometry (as in the present investigated test case), rather than the effects of blood-surface contact. The results obtained in this test case investigation, confirm the effectiveness of the proposed function for a quantitative analysis of spiral flow in medical devices.

Blood Flow Velocity↗
PubMed2004

Cardiac calcium evaluation in hemodialysis patients with multisection spiral computed tomography.

AIM: The aim of this study is cardiac calcium content evaluation in hemodialysis patients by a new technique, based on ultrafast multisection CT (MTC). METHODS: The study was carried out on 30 HD patients, 14 F and 16 M, average age 57.7 +/- 13.9 years, average HD age 57.3 +/- 47.4 months. The intact PTH levels were 625.4 +/- 571 pg/mL. Serum calcium, phosphate and CaxP product were 9.75 +/- 0.84 mg/mL, 6.21 +/- 1.01 mg/dL and 60.2 +/- 10.7 mg2/dL2, respectively. RESULTS: The values obtained with the MTC technique were reported in terms of Agatson scores. Score values frankly in the pathologic range (>100) were found in 24 patients (80%). Correlation analysis has shown positive and significant correlation coefficients of the score with patients' age (p = 0.003), serum calcium (p = 0.012), CaxP (p = 0.015), iPTH (p = 0.049), and borderline, to HD age (p = 0. 06). CONCLUSION: Risk factors for cardiac calcification are mainly age, degree of hyperparathyroidism, increased CaxP and serum calcium levels. A control of calcium phosphate parameters in hemodialysis patients seems to be mandatory to avoid increased severity of coronary artery disease.

Adult↗
PubMed2003

Numerical simulation of a realistic total cavo-pulmonary connection: effect of unbalanced pulmonary resistances on hydrodynamic performance.

Total cavo pulmonary connection (TCPC) is one of the surgical techniques adopted to compensate the failure of the right heart in pediatric patients. The main goal of this procedure is the realization of a configuration for the caval veins and for the pulmonary arteries that can guarantee as low as possible pressure losses and appropriate lung perfusion. Starting from this point of view, a realistic TCPC with extracardiac conduit (TECPC) is investigated by means of Computational Fluid Dynamics (CFD) to evaluate the pressure loss under different pressure conditions, simulating different vessel resistances, on the pulmonary arteries. A total flow of 3 L/min, with a distribution between the inferior vena cava (IVC) and the superior vena cava (SVC) equal to 6/4, was investigated; three different boundary conditions for the pressure were imposed, resulting in three simulations in steady-state conditions, to the right pulmonary artery (RPA) and to the left pulmonary artery (LPA), simulating a balanced (deltaP(LPA-RPA) = 0 mmHg) and two unbalanced pulmonary resistances to blood flow (a pressure difference deltaP(LPA-RPA) = +/- 2 mmHg, respectively). The geometry for the TECPC was realized according to MRI derived physiological values for the vessels and for the configuration adopted for the anastomosis (the extra-cardiac conduit was inclined 22 degrees towards the left pulmonary artery with respect to the IVC axis). The computed power losses agree with previous in vitro Particle Image Velocimetry investigations. The results show that a higher resistance on the LPA causes the greater pressure loss for the TECPC under study, while the minimum pressure loss can be achieved balancing the pulmonary resistances, subsequently obtaining a balanced flow repartition towards the lungs.

Child↗
PubMed2001

Use of low-density foams as pressure amplifiers in equation-of-state experiments with laser-driven shock waves.

The applicability of foams to equation of state experiments with laser-produced shocks has been studied. The pressure increase due to impedance mismatch at the payload-foam interface was measured experimentally using sub-ns laser pulses smoothed with phase zone plates. Foams of density in the range 5-900 mg/cm(3) and of thicknesses of 50-150 microm were used. A model has been developed to study pressure amplification and the conditions under which the shock is stationary. Two-step two-material targets, allowing simultaneous measurements of the shock velocities in the two materials, were then used to obtain relative equation of state data. Pressures higher than 100 Mbar were achieved in gold.

Journal Article↗
PubMed2001

Oral contraceptives and colorectal cancer risk: a meta-analysis.

Several studies have suggested an inverse association between use of combined oral contraceptives (OC) and the risk of colorectal cancer and here we present a meta-analysis of published studies. Articles considered were epidemiological studies published as full papers in English up to June 2000 that included quantitative information on OC use. The pooled relative risks (RR) of colorectal cancer for ever OC use from the 8 case-control studies was 0.81 (95% confidence interval (CI): 0.69-0.94), and the pooled estimate from the 4 cohort studies was 0.84 (95% CI: 0.72-0.97). The pooled estimate from all studies combined was 0.82 (95% CI: 0.74-0.92), without apparent heterogeneity. Duration of use was not associated with a decrease in risk, but there was some indication that the apparent protection was stronger for women who had used OCs more recently (RR = 0.46; 95% CI: 0.30-0.71). A better understanding of this potential relation may help informed choice of contraception.

Case-Control Studies↗
PubMed1998

Valproate-induced epileptic tonic status.

We observed a young patient with slight mental retardation, suffering from drug-resistant tonic-clonic seizures, who presented a status epilepticus (SE), in two separate periods when valproic acid (VPA) was added to the phenobarbital (PB) already being used in the patient's therapy. The VPA-induced SE was characterized by normal plasma levels of antiepileptic drugs (AEDs), normal ammonemia and normal liver function. The case we studied represents the first report on a VPA-induced SE. Furthermore the case confirms that VPA, as well as causing encephalopathy secondary to hyperammonemia, may also provoke a primary involvement of the central nervous system (CNS), specially when used in young epileptic, mentally retarded subjects. In an attempt to explain the paradoxical effect of VPA we hypothesise that the SE could be due to an increase in excitatory activity producing a consequent epileptogenic effect in those subjects with a predisposition for toxic reaction to VPA therapy due to congenital anomalies of neural networks.

Adolescent↗
PubMed1998

Recurrent cutaneous leiomyosarcoma.

Cutaneous leiomyosarcoma is a rare tumour, accounting for 2.3% to 6.5% of all soft tissue sarcomas. The case of a young patient with a cutaneous leiomyosarcoma on the right gluteal region is here presented. The lesion misdiagnosed as a keloid after primary excision of histiocytoma had a two-year history, had been excised twice. The tumour was widely excised, and the wound closed primarily. No recurrence or distant metastasis are reported 26 months after the initial presentation. Clinical, histological, immunohistochemical features and surgical strategies of the reported case are discussed and compared with literature.

Adult↗
PubMed1991

Indications and adequacy of automated peritoneal dialysis in 74 patients.

Experience with chronic intermittent peritoneal dialysis is reviewed to focus on automated peritoneal dialysis (APD) regimens, adequacy and indications. From 1969 to 1990, 74 ESRD patients were treated: 59 patients with Intermittent Peritoneal Dialysis (IPD: 30-40 l x 3/week) and fifteen patients with hour Daily Peritoneal Dialysis (DPD: 25 l x 6 nights/week). Fourty-four patients were regularly treated with IPD. Of these 33 were adequately dialysed, maintaining residual renal function, whilst oligo-anuric patients developed underdialysis. DPD patients were adequately dialysed, having satisfactory peritoneal clearances. Peritonitis rate was 1/19.2 pt months in IPD patients and 1/13.4 pt months in DPD patients. Technique survival was 78% at the end of the first year, and 52% the second year. IPD is adequate only for low body weight patients with residual renal function. In-hospital IPD must be taken into account only for patients unable to perform dialysis without partner assistance. Home DPD, like CCPD and NPD, is generally adequate and yields fairly good quality of life, but the cost is high, probably because of limited ADP diffusion. Prescription must be therefore restricted to patients unable to perform dialysis with working partners, workers who cannot cope with CAPD exchanges, and CAPD failures.

Adolescent↗
PubMed1990

Membranous nephropathy associated with giant lymph node hyperplasia. A case report with histological and ultrastructural studies.

A young woman presented with nephrotic syndrome due to membranous nephropathy and a localized form of giant lymph node hyperplasia (Castleman's disease) occurring as a large intra-abdominal mass. Five months after surgical removal of the mass, only mild proteinuria persisted. Twenty months later a second kidney biopsy showed a near-normal morphology. Six years later the patient was free of symptoms and had normal urinalysis. Reviewing the pertinent literature, it seems to be the first case of a biopsy-proven cure of membranous nephropathy in a patient with membranous nephropathy and Castleman's disease.

Adolescent↗
PubMed1981

Intraperitoneal insulin in uraemic diabetics undergoing continuous ambulatory peritoneal dialysis.

The kinetics of absorption of intraperitoneally administered insulin were studied in nine uraemic insulin-dependent diabetics undergoing continuous ambulatory peritoneal dialysis (CAPD). In each of three studies 20 U of regular insulin was directly injected as a bolus into the peritoneal cavity through an indwelling Tenckhoff catheter. In two procedures the insulin injection was followed by the instillation of either 2 litres of 1.5% dextrose dialysates or 2 litres of 4.5% dextrose dialysate. In the third 20 ml of saline was used to flush the tubing. Plasma free insulin values rose more rapidly and reached significantly higher concentrations (55.6 +/- 18.8 mU/l) when the insulin had been injected into an empty peritoneal cavity than when it was followed by dialysate. These differences were observed despite the fact that most of the insulin injected was retained by the patients. Since the plasma insulin values did not differ after instillations of dialysate containing 1.5% and 4.5% dextrose, the osmolality of the dialysate seemed not to affect insulin absorption, and the dilution of the insulin probably delayed its transfer through the peritoneum. These findings suggest that insulin given intraperitoneally to patients undergoing CAPD will be most effective if it is given into an empty peritoneal cavity at least 30 minutes before the dialysate is instilled.

Blood Glucose↗