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S Rinaldi

Publications and source records attributed to S Rinaldi.

At least 73 records · Page 4Linked to original sources
PubMed1996

Transglutaminase activity is related to CAG repeat length in patients with Huntington's disease.

Huntington's disease (HD) is a neurodegenerative disorder associated with CAG repeat expansion. We measured transglutaminase (TGase) activity in lymphocytes from 35 HD patients and from healthy individuals to ascertain whether it was altered in this condition. TGase activity was above maximum control levels in 25% of HD patients; it was correlated with the age of the patient and inversely correlated with the CAG repeat length. These results suggest that: (1) HD could be biochemically heterogeneous, and (2) the length of the CAG repeat expansion/TGase ratio could be important in the manifestation of HD.

Adult↗
PubMed1996

Remarks on food chain dynamics.

The main modes of behavior of a food chain model composed of logistic prey and Holling type II predator and superpredator are discussed in this paper. The study is carried out through bifurcation analysis, alternating between a normal form approach and numerical continuation. The two-parameter bifurcation diagram of the model contains Hopf, fold, and transcritical bifurcation curves of equilibria as well as flip, fold, and transcritical bifurcation curves of limit cycles. The appearance of chaos in the model is proved to be related to a Hopf bifurcation and a degenerate homoclinic bifurcation in the prey-predator subsystem. The boundary of the chaotic region is shown to have a very peculiar structure.

Animals↗
PubMed1996

Complications linked to chronic peritoneal dialysis in children after kidney transplantation: experience of the Italian Registry of Pediatric Chronic Peritoneal Dialysis.

Our objective was to evaluate the infectious complications of the post-transplant period attributable to the persistence of catheter and other complications when chronic peritoneal dialysis (CPD) was performed post-transplantation. The design was a retrospective study, and the setting was an Italian registry of pediatric chronic peritoneal dialysis. There were 86 pediatric renal transplants (9/86 from living related donors, 2/86 simultaneous liver and kidney transplantation for oxalosis). Six of 86 transplants were lost at follow-up. Mean age of the children (n = 80) at transplantation was 9.3 years (range: 1.7-21 years). They had been on CPD for a mean period of 1.7 years (range: 0.2-4.6 years). During CPD, 67 peritonitis episodes (80% related to exit-site and/or tunnel infections) were observed, with an incidence of peritonitis of one episode per 16 months CPD. The mean safe interval of peritonitis and/or exit-site or tunnel infection was 208 days (range: 36-1897 days). The mean time of catheter removal was 80.3 days (range: 0-216 days) post-transplantation. During the first month post-transplantation, one episode of peritonitis secondary to a sepsis occurred in one child. No other episodes of peritonitis or exit-site and/or tunnel infections were observed. Two of 80 children returned to CPD (at four and at 12 months, respectively) because of persistent allograft failure. Furthermore, 12 patients were on CPD because of temporary graft failure. In all these patients the pretransplant peritoneal dialysis (PD) catheter was utilized, with no complications. These data show that the persistence of the PD catheter after kidney transplantation has produced no infections or other complications. What is more, the catheter was safely utilized during acute rejection or primary allograft nonfunction.

Adolescent↗
PubMed1996

Comparison of patient hospitalization in chronic peritoneal dialysis and hemodialysis: a pediatric multicenter study.

Patient hospitalization was compared in 207 pediatric patients (age < or = 15 years at the start of dialysis) on chronic peritoneal dialysis (CPD) (127 patients) or center hemodialysis (HD) (80 patients), treated in 17 dialysis centers during the period 1989 to 1994, and followed up for at least three months. The hospitalization rate was expressed as hospital days per patient-month, and was calculated on the overall period of treatment and separately for the first and second year. Since the age at start of dialysis markedly differed between CPD (8.2 +/- 4.7 years) and HD (11.2 +/- 2.9 years) patients (with no HD patient younger than five years), results are separately presented in three patient groups: CPD patients aged < 5 years (A); CPD patients aged five to 15 years (B); HD patients (C). The duration of hospitalization was subdivided according to the following different causes: routine (monitoring of dialysis adequacy), complications of the modality, patient primary renal disease, and other causes. The results are presented in Table 1. A statistically significant difference in total days hospitalized was found between each of the two groups of CPD patients and the HD patients; the results for hospitalization for dialysis-related complications were higher in the group of younger children on CPD, while the difference between the two age-matched groups of patients on CPD and HD was not significant.

Adolescent↗
PubMed1996

Wear assessment in bileaflet heart valves.

Sorin Biomedica has accumulated 20 years of experience in designing and manufacturing heart valves as well as in the development of turbostratic carbons, both as bulk coating (pyrolytic carbon, PyC) and as a thin film (Carbofilm). In designing a bileaflet valve, where hinges represent the most critical elements since wear occurs mainly at these points, we took into account: a) theoretical considerations on the geometry (flat-to-flat vs. curved-to-flat) of the coupling elements undergoing impact wear; b) kinematic coupling (sliding, rotation, rolling) between the moving parts in relation to friction wear; c) experimental wear rates of different material couples (PyC/PyC, metal/PyC) assessed by paying attention to test artifacts due to particle contamination; and d) wear mechanisms involving brittle fracture mechanics for bulk PyC and ductile fracture mode for metals. On the basis of the above evaluations a Carbofilm coated titanium alloy housing and PyC leaflets were developed for the Sorin Bicarbon valve. A flat-to-flat coupling between hinge stops and mating pivot surfaces for reducing the impact wear and a rolling action aimed at minimizing the friction wear were designed for the hinge. The Bicarbon long term durability has been assessed by accelerated wear tests conducted in comparison with clinically accepted bileaflet prostheses (CarboMedics and St. Jude Medical). The main results for the Bicarbon valve were, wear rates slightly lower or comparable to those found in the reference valves and wear morphology free from microfractures, while deep cracks associated with higher stress concentrations were detected on the PyC components of the reference valves. No mechanical failure or loss of functionality occurred up to 2,100 million cycles (equivalent of 52.5 years).

Animals↗
PubMed1995

Design and performance characteristics of the Pericarbon Stentless valve.

The Pericarbon Stentless valve (PS) in an unstented bioprosthesis made of glutaraldehyde tanned bovine pericardium. Its design concept and chemical fixation process are based on those developed for the stented Pericarbon valve, which has been in clinical use for eight years. The two-sheet design and the special suture pattern with which the two pieces of pericardium are attached aim at avoiding stress concentration during function. The resulting cylindrical structure is a relatively low-profile valve conduit, which can be further trimmed by the implanting surgeon to the individual patient's specific anatomical requirements. The main advantage of the stentless concept is optimum hemodynamic characteristics, inherent in the high external/internal diameter ratio. The unique design and material selection of the PS valve offer the following advantages: Free-hand insertion similar to that with homograft aortic valves. Absence of any fabric cover or reinforcement providing a maximum effective orifice area and reduced risk of infection. Wide range of available sizes from 15 mm to 29 mm. Special methods have been developed for laboratory testing of the PS. These, and the in vitro results are presented in detail, with particular emphasis on the hydrodynamic performances under different flow conditions. Clinical implantation of the Pericarbon Stentless valve has already been started, and early results in the aortic position show good hemodynamic function and a low rate of complications.

Animals↗
PubMed1994

Relationship between some design characteristics and wear in the Bicarbon heart valve prosthesis.

The hinge design of a new bileaflet valve (Bicarbon) is presented in relation to the long-term durability characteristics. Theoretical considerations supported by experimental findings, lead to the identification of two different wear mechanisms acting in bileaflet valves, i.e. impact and friction wear. Impact wear, caused by the collision between the hinge stops and inflow surface of the leaflet pivots, is the predominant phenomenon; it is mostly influenced by the design of the coupling elements. The wear due friction is significantly less important, given a proper kinematic coupling and a thorough washout. These different mechanisms can significantly affect the wear resistance and long-term reliability of bileaflet valves; therefore, they have been properly taken into account in designing the new valve model. The safety of the overall material and design solutions adopted in the Bicarbon valve has been confirmed by extensive accelerated durability tests resulting in no mechanical failure or loss of functionality.

Animals↗
PubMed1993

Relapsing gross haematuria in Münchausen syndrome.

A 10-year-old female with relapsing gross haematuria and Münchausen syndrome is reported, emphasizing the rarity of this situation in children and the difficult diagnostic pathway. A careful personality study of the patient and family members is absolutely necessary in order to proceed with diagnosis and successful treatment.

Child↗
PubMed1993

A randomized trial of cyclosporine in steroid-resistant idiopathic nephrotic syndrome.

To compare the efficacy (induction of remission) and safety of cyclosporine (CsA) with those of supportive therapy in patients with steroid-resistant idiopathic nephrotic syndrome (INS), we organized an open, prospective, randomized, multicentric, controlled study for parallel groups, stratified for adults and children. Forty-five patients with steroid-resistant INS were randomly assigned to supportive therapy or CsA (5 mg/kg/day for adults, 6 mg/kg/day for children) for six months, then tapered off by 25% every two months until complete discontinuation. Four patients were lost to follow-up. During the first year 13/22 CsA-treated patients versus three of 19 controls attained remission of the nephrotic syndrome (P < 0.001). A symptom score was assessed at time 0 and at six months. The mean score significantly decreased in the CsA group (P < 0.001), but remained unchanged in the controls. At month 6 the mean urinary protein excretion, the mean serum proteins and plasma cholesterol had significantly improved in the CsA group but were not changed in the controls. There were no significant differences in serum creatinine and creatinine clearance between treatments (interaction time* treatments, P = 0.089 and P = 0.935, respectively) at month 6 versus basal. The CsA-related side-effects were mild; no significant difference in blood pressure between the two groups was seen at any time. This study shows that CsA can bring about remission in some 60% of patients with steroid-resistant INS. In patients with normal renal function and without severe hypertension, CsA at the therapeutic scheme adopted did not produce severe renal or extrarenal toxicity.

Adolescent↗
PubMed1993

Cyclosporin versus cyclophosphamide for patients with steroid-dependent and frequently relapsing idiopathic nephrotic syndrome: a multicentre randomized controlled trial.

OBJECTIVE: To compare the efficacy (maintenance of remission), safety and tolerability of cyclosporin (CsA) with those of cyclophosphamide in patients with steroid-dependent or frequently relapsing nephrotic syndrome (NS). DESIGN: Open, prospective, randomized, multicentre, controlled study for parallel groups, stratified for adults and children. The setting was in nephrological departments in Italy. SUBJECTS AND INTERVENTIONS: Seventy-three patients with steroid-sensitive idiopathic NS admitted to the study were randomly assigned to cyclophosphamide (2.5 mg/kg/day) for 8 weeks or CsA (5 mg/kg/day in adults, 6 mg/kg/day in children) for 9 months, tapered off by 25% every month until complete discontinuation at month 12. Seven patients lost to follow up were not considered in the analysis. The remaining 66 patients were followed up for 3-24 months after randomization. MAIN OUTCOME MEASURES: Relapse-free survival; number of N.S. relapses/patient/year; cumulative dose of prednisone/patient; laboratory investigations (kidney and liver functions, haematological parameters); incidence of adverse events. RESULTS: At month 9, 26 of 35 CsA-treated patients were still in complete remission and a further five patients were in partial remission; 18 of 28 cyclophosphamide-treated patients were in complete remission, and one in partial remission (P = NS). No difference between adults and children was seen with either treatment. The risk of relapse was similar between frequent relapsers (19 of 22) and steroid-dependent patients (8 of 14) given CsA, and those given cyclophosphamide (5 of 15 and 6 of 15). The mean number of relapses per year and the mean dose of prednisone per year were significantly less (P < 0.001) in both groups for the experimental year than for the year before randomization. At 2 years, 25% of the patients given CsA (50% adults and 20% children) and 63% of those given cyclophosphamide (40% adults and 68% children) had not had any relapse of NS. Tolerance to the two drugs was generally good. The CsA-related side-effects were mild and disappeared after drug discontinuation. CONCLUSIONS: This study shows that both treatments are effective and well tolerated; more patients given cyclophosphamide had stable remissions.

Adolescent↗
PubMed1993

Chronic peritoneal dialysis catheters in pediatric patients: experience of the Italian Registry of Pediatric Chronic Peritoneal Dialysis.

During the period 1986-1991, 140 pediatric patients [age < or = 15 years at the start of chronic peritoneal dialysis (CPD)], belonging to 15 dialysis centers, were enrolled in the Italian Registry of Pediatric Chronic Peritoneal Dialysis. Data on 188 peritoneal catheters were collected: 161 catheters were Tenckhoff (144 double-cuff, 17 single-cuff), and 27 were two-cuff Valli-type catheters. All catheters were surgically inserted; the entry site was in the midline in 84 cases and paramedian in 104. An omentectomy was performed in 78.8% of the cases. Apart from peritonitis, there were 161 catheter-related complications (103 exit-site infections, 17 leakages, 15 obstructions, 15 outer-cuff extrusions, 5 hemoperitoneum, 6 others) observed during 2687.5 dialysis-months, with an incidence of one complication every 16.7 dialysis-months. Fifty-five catheters (29.2%) were removed; infection (39 cases) was the main cause for removal, followed by obstruction (9 cases), dislocation, and outer-cuff extrusion (2 cases each). Actuarial survival of all catheters was 79.7% at 1 year, 66.6% at 2 years, 42.8% at 3 years, and 39.8% at 4 years. No difference in catheter survival was observed according to the entry site. When considering the age of the patients at catheter insertion, a difference close to statistical significance was found (p = 0.06).

Actuarial Analysis↗
PubMed1992

Peritonitis in children undergoing chronic peritoneal dialysis (CPD): data from the Italian Registry of Pediatric CPD.

During the period 1986-1990, 119 patients were enrolled in the Italian Registry of Pediatric CPD. CAPD was largely predominant in the first 3 years, while CCPD accounted for 48% of dialysis months in the period 1989-1990. The connect-disconnect system was a Y set for all patients during the whole observation period. The incidence of peritonitis decreased from 1 episode: 10.9 patient-months in 1986 to 1:19.8 in 1988, and then passed to 1:16.2 in 1990. A comparison of the incidence of peritonitis between CAPD and CCPD, referring to the 1989-1990 period, showed no significant difference. The percentage of positive peritoneal fluid cultures changed from 48% in 1986 to 73% in 1990. Gram-positive bacteria, primarily Staphylococcus aureus and Staphylococcus epidermidis, accounted for most of the isolated organisms. Candida albicans was cultured in 3 cases both in 1986 and 1987. Exit site infection was the predominant (82%) complication, followed by leakage and catheter cuff extrusion. The hospitalization rate for peritonitis resulted persistently high (61% of episodes) and the mean duration was 12.7 days. Of the 8 patients who were switched to hemodialysis, 4 had recurrent peritonitis and 1 Candida albicans peritonitis.

Adolescent↗
PubMed1992

[J-pouch after total gastrectomy].

The Authors report their initial experience with the construction of a J-pouch as restorative surgery following total gastrectomy (TG) for malignant neoplasms. In the last 10 months of the 1990 upon 52 interventions for gastric cancer 31 TG were performed, and in 13 cases a J-pouch on the proximal end of the jejunal segment was constructed. No mortality or specific morbidity was registered using the totally stapled technique. Within one month 3/4 of the patients had normal meals as far as quantity and quality; also the foamy regurgitation seemed to be minimal. The ease of the reconstructive technique and the short term results obtained encourage the use of such approach.

Esophagus↗
PubMed1991

[A new reconstructive model after total proctectomy].

The Authors describe a new reconstructive model after total proctectomy: the S-E colo-anal anastomosis (S-E CAA). The technical requisites of this variant are discussed and compared with more traditional reconstruction models. At a first evaluation of the results, the S-E CAA seems to be able to sensibly ameliorate the course and the outcome of the anastomosis and to hasten the recovery of the normal sphincteric function.

Anal Canal↗