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Biomedical subjects

G Rizzoni

Publications and source records attributed to G Rizzoni.

At least 55 records · Page 3Linked to original sources
PubMed1996

Cyclosporine-induced transient renal hypoperfusion in adolescent transplant recipients.

We investigated the acute hemodynamic effect of a single oral dose of cyclosporine A (CsA) given as part of the immunosuppressive schedule in six adolescents with renal transplants. Renal plasma flow (RPF) and glomerular filtration rate (GFR) were determined by continuous infusion of inulin and amino-hippuric acid for 12 h. A fall in both GFR and RPF was observed 4-6 h after peak plasma CsA levels. No significant correlation was found with CsA dosage or any pharmacokinetic parameters. This study demonstrates that CsA also has a vasoconstrictory effect in adolescent recipients; this could be one of the causes of its nephrotoxicity.

Adolescent↗
PubMed1996

Molecular analysis of the cystinuria disease gene: identification of four new mutations, one large deletion, and one polymorphism.

A cystinuria disease gene (rBAT) has recently been identified, but evidence strongly suggests that only Type-I cystinuria is due to mutations in this gene. Sixteen point mutations and a large deletion causing the disease have so far been described in the rBAT gene sequence. To identify new mutated alleles, genomic DNA was analyzed, after the determination of the entire genomic structure of the rBAT gene, by RNA-single strand conformation polymorphism analysis, an accurate and sensitive method able to detect nucleotide changes. Four new point mutations, a large deletion, and a common intragenic polymorphism were detected. These new mutations increase to 22 the number of mutated alleles so far characterized in rBAT. In addition, the frequency of 21 mutations was assessed in a sample of accurately defined Type-I cystinuria chromosomes. They account for about 58% of all Type-I chromosomes, mutation M467T being the most common (0.26).

Alleles↗
PubMed1996

Bilateral nephrectomy stopped disease progression in plasma-resistant hemolytic uremic syndrome with neurological signs and coma.

Four women were admitted over three years because of anemia and renal failure. They had evidence of hemolytic uremic syndrome (HUS) with severe vascular involvement and glomerular collapse. Despite intensive plasma exchange, all patients developed neurologic signs (with seizures and coma in 2) and papilledema. Three developed refractory hypertension and three required dialysis. All patients had abnormal von Willebrand factor (vWF) fragmentation as reflected by decreased high molecular weight and increased low molecular weight vWF multimers in the circulation. Assuming that the disease was sustained by shear stress-induced abnormal vWF fragmentation in damaged renal microvasculature, bilateral nephrectomy was done. Surgery was followed within two weeks by complete hematologic and clinical remission consistently associated with the restoring of vWF fragmentation pathway to normal. We speculate that in HUS resistant to plasma exchange or infusion, removing the kidneys eliminates a major site of vWF fragmentation, which would limit platelet activation and protect patients from the further spreading of microvascular lesions.

Adult↗
PubMed1996

Abnormal hypertensive response during exercise test in normotensive transplanted children and adolescents.

We investigated the cardiovascular and respiratory conditions, at rest and in response to stress testing, in 10 children and adolescents with successful renal transplantation, to release certifications for participation in sports. Our patients were aged more than 6 years, transplanted 6 months or more before the study, with creatinine clearance > 40 ml/min/1.73 m2, without hypertension at rest. All but 1 were on cyclosporine A, prednisone and azathioprine. Two control study groups with the same chronological age and body surface area were paired with our patients. They underwent a graded exercise tread-mill test, during which maximal blood pressure and heart rate were recorded. Resting electrocardiogram, dynamic 24-hour electrocardiogram Holter monitoring and mono- and bidimensional echocardiograms were obtained before the test. Spirometry was performed to study lung flow and volume. A questionnaire collected information about physical activity patterns. Four categories, according to practice, frequency and duration of exercise, were identified: nonactive, starters, experienced and very experienced. Most children and adolescents were sedentary or mildly interested in sports and during treadmill test we observed reduced exercise capacity and systolic hypertensive response to increasing exercise testing.

Adolescent↗
PubMed1996

X-linked Alport syndrome: an SSCP-based mutation survey over all 51 exons of the COL4A5 gene.

The COL4A5 gene encodes the alpha5 (type IV) collagen chain and is defective in X-linked Alport syndrome (AS). Here, we report the first systematic analysis of all 51 exons of COL4A5 gene in a series of 201 Italian AS patients. We have previously reported nine major rearrangements, as well as 18 small mutations identified in the same patient series by SSCP analysis of several exons. After systematic analysis of all 51 exons of COL4A5, we have now identified 30 different mutations: 10 glycine substitutions in the triple helical domain of the protein, 9 frameshift mutations, 4 in-frame deletions, 1 start codon, 1 nonsense, and 5 splice-site mutations. These mutations were either unique or found in two unrelated families, thus excluding the presence of a common mutation in the coding part of the gene. Overall, mutations were detected in only 45% of individuals with a certain or likely diagnosis of X-linked AS. This finding suggests that mutations in noncoding segments of COL4A5 account for a high number of X-linked AS cases. An alternative hypothesis is the presence of locus heterogeneity, even within the X-linked form of the disease. A genotype/phenotype comparison enabled us to better substantiate a significant correlation between the degree of predicted disruption of the alpha5 chain and the severity of phenotype in affected male individuals. Our study has significant implications in the diagnosis and follow-up of AS patients.

Adult↗
PubMed1996

Repeated successful pregnancies after kidney transplantation in 102 women (Report by the EDTA Registry).

BACKGROUND: Between 1967 and 1990, 820 successful pregnancies in 718 women on renal replacement therapy (RRT) were reported to the EDTA Registry. METHODS: This study analyses data on repeated successful pregnancies in 102 of these women, of whom 99 had two and three had three pregnancies. RESULTS: Primary renal diseases were mainly glomerulonephritis (41%), pyelonephritis (32%), and congenital malformations such as cystic diseases and hypoplasia or dysplasia (3%). Mean age at start of RRT was 21 years +/-5 SD. Ninety-four per cent of the women had the same transplant during the first and second pregnancies; 85% of these were alive with their first graft and 9% with a second graft; 4% were retransplanted after the first pregnancy and 2% were back on dialysis during the second pregnancy. Of the mothers with two successful pregnancies, two-thirds had a serum creatinine below 121 micromol/l after the first or after the second pregnancy. Six mothers lost their first graft after the first pregnancy. None of the mothers had died after delivery of the second or third baby. Several features of the first and the second pregnancy in these mothers were quite similar. Mean gestational age was 36 weeks+/-3SD during first and second pregnancy. Mean birth weight (height) of the first child was 2490 g+/-660 SD (48 cm+/-4 SD) and 2587 g+/-639 SD (50 cm+/-3 SD) of the second child (NS). Neonatal mortality was 4% after the first and second delivery; congenital abnormalities were found in five and three children respectively. CONCLUSIONS: Fourteen per cent of mothers who had a successful pregnancy on RRT subsequently had a second baby. Repeated pregnancies should not adversely affect graft function and/or fetal development provided that graft function was well preserved at the time of conception.

Adult↗
PubMed1996

Can provocative growth hormone testing predict the response to recombinant human growth hormone (rhGH) treatment?

Treatment with rhGH has been proven to be useful in children with chronic renal insufficiency and stunted growth. The aim of this study was to assess the usefulness of endocrinological provocative testing in predicting results to rhGH treatment. Endocrinological investigations performed in 14 children on renal replacement therapy did not correlate with increment of height velocity in the first year of rhGH therapy. It is concluded that no endocrinological testing is useful before starting rhGH treatment; other predictors of the response to rhGH administration are needed.

Adolescent↗
PubMed1996

[Combined heart-kidney transplantation in pediatric age].

A case of simultaneous heart and kidney transplantation is presented in a 12 years old girl. The patient suffered from dilated cardiomyopathy and end-stage kidney disease. Bilateral vesico-renal refluxes were corrected at the same time of the duplex transplantation. A multiorgan harvesting from a pediatric 8 years old donor was utilized. Follow-up is 40 months. Cytomegalovirus (CMV) infection and acute tubular necrosis from haemoglobinuria were transient complications. Hemolysis from bypass and extracorporeal circulation was involved as pathogenetic factor of the acute tubular necrosis. Cardiac and renal function remain excellent and the child is fully recovered and resumed a normal and active life. Combined heart and kidney transplantation may be of benefit in selected patients, also in pediatric age.

Age Factors↗
PubMed1995

Major COL4A5 gene rearrangements in patients with juvenile type Alport syndrome.

Mutations in the COL4A5 gene, which encodes the a5 chain of type IV collagen, are found in a large fraction of patients with X-linked Alport syndrome. The recently discovered COL4A6, tightly linked and highly homologous to COL4A5, represents a second candidate gene for Alport syndrome. We analyzed 177 Italian Alport syndrome families by Southern blotting using cDNA probes from both COL4A5 and COL4A6. Nine unrelated families, accounting for 5% of the cases, were found to have a rearrangement in COL4A5. No rearrangements were found in COL4A6, with the exception of a deletion encompassing the 5' ends of both COL4A5 and COL4A6 genes in a patient with Alport syndrome and leiomyomatosis. COL4A5 rearrangements were all intragenic and included 1 duplication and 7 deletions. Polymerase chain reaction (PCR) analysis was carried out to characterize deletion and duplication boundaries and to predict the resulting protein abnormality. The two smallest deletions involved a single exon (exons 17 and 40, respectively), while the largest ones spanned exons 1 to 36. The clinical phenotype of patients in whom a rearrangement in COL4A5 was detected was severe, with progression to end-stage renal failure in juvenile age and hypoacusis occurring in most cases. These data have some important implications in the diagnosis of patients with Alport syndrome.

Adolescent↗
PubMed1995

A novel missense mutation in exon 3 of the COL4A5 gene associated with late-onset Alport syndrome.

We have identified a novel missense transition (362G-->A) in exon 3 of the COL4A5 gene in a male patient with late-onset Alport syndrome. We used non-isotopic single strand conformation polymorphism, heteroduplex analysis, and automated DNA sequencing. The mutation changes a conserved glycine at codon 54 for an aspartic acid (Gly54Asp), which abolishes a BstNI site. Using restriction analysis, we identified the heterozygous carrier status in the two daughters of the proband. Our findings are in keeping with the hypothesis that slower progressive forms of Alport syndrome are more often associated with missense mutations rather than large deletions or frameshifts. This is the first mutation described in the N-terminus triple helical 7S domain of the COL4A5 gene in an Alport syndrome patient.

Adolescent↗
PubMed1995

Risks of acute renal failure after cardiopulmonary bypass surgery in children: a retrospective 10-year case-control study.

To our knowledge there are no case-control studies that have examined the main risk factors for acute renal failure (ARF) following cardiopulmonary bypass surgery in children. We therefore evaluated the potential risk factors in a large retrospective case-control study. Sixty-one of 2262 children (2.7%) developed postcardiopulmonary bypass surgery ARF requiring peritoneal dialysis (PD) from 1982 to 1991. Fifty-eight of 61 cases (median age 8.5 months) were selected by systematic sampling and matched with 176 controls who did not develop ARF. The four matching variables were age, cardiopulmonary bypass and circulatory arrest duration, and year of operation. Mortality rate was 79% in cases (controls: 18%). Forty-three of 48 of the deceased cases did not recover renal function: no renal cause of death was found; 13 of 61 cases survived and recovered renal function. Multiple regression analysis showed the following significant risk factors for postcardiopulmonary bypass surgery ARF: central venous hypertension > 12 h (odds ratio (OR) 9.6); systolic arterial hypotension > 12 h (OR 8.9); dopamine dosage > 15 micrograms/kg/min (OR 3.0); adrenaline (OR 5.9) and isoproterenol (OR 13.5) use. High preoperative serum creatinine, cyanosis, and vasodilator use were not significant risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1995

Macromolecular IgA and abnormal IgA reactivity in sera from children with IgA nephropathy. Italian Collaborative Paediatric IgA Nephropathy Study.

This multicenter study investigated the characteristics of circulating IgA molecules in 77 children: 42 had primary IgA nephropathy (IgAN), 20 were non-IgA glomerulonephritides (CGN) and 15 had urological problems (U). Fifteen assays were employed including the detection of macromolecular IgA [IgA immune complexes (IgAIC) by the conglutinin (K) assay, heavy molecular weight IgA in 2.5% polyethylene glycol (PEG), mixed IgA/IgGIC (Jacalin assay), IgA-Fibronectin (IgA-F) aggregates]IgA antibodies to alimentary antigens (gliadin, glycgli, glutein, ovalbumin, bovine serum albumin) and IgA binding to mesangial antigens (fibronectin, laminin, type IV collagen) or polycations (poly-L-lysine). Total IgA and IgA reacting with jacalin, supposed to bear an altered galactosylation, were measured as well. Mean levels of each kind of macromolecular IgA were significantly increased in children with IgAN in comparison to U disease (K-IgAIC p < 0.05, PEG-IgAIC p < 0.01, IgA/IgGIC p < 0.004, IgA-F aggregates p < 0.0003). However, IgA-F were the only macromolecular IgA significantly higher in IgAN than in CGN (p < 0.0005). IgA-F aggregates did not correlate with any urinary sign of activity, while K-IgAIC data were significantly related with microscopic hematuria (p < 0.05) and past history of gross hematuria (p < 0.02). Children with IgAN had mean levels of IgA reacting with the lectinic fractions of gliadin significantly higher than CGN (p < 0.01) and U groups (p < 0.003). IgAN displayed an enhanced production of IgA reacting with mesangial matrix components vs CGN (p < 0.03) and U (p < 0.0003) groups and showed altered interactions with positively charged molecules (poly-L-Lysine, p < 0.01) and carbohydrate residues (jacalin p < 0.05). In IgAN there is an increased circulation of altered IgA favouring the formation of macromolecular IgA, including true IgAIC or IgA aggregated by carbohydrate interactions. The affinity for the mesangial matrix glycoproteins and for the mesangial area electrical charge might further enhance the trapping and deposition of the immune material containing IgA. IgA-F aggregates seem to be a marker of this event, while complement binding molecules in IgAIC correspond to the hematuric manifestation of the nephritogenic process.

Adolescent↗
PubMed1994

Haemolytic-uraemic syndrome in childhood: surveillance and case-control studies in Italy. Italian HUS Study Group.

Seventy-six cases of haemolytic-uraemic syndrome (HUS) were collected over a 4-year period during a surveillance and case-control study. The annual incidence of 0.2 per 100,000 children aged 0-14 years is lower than in other countries; 34% had no prodromal diarrhoea. Evidence for verocytotoxin-producing Escherichia coli (VTEC) infection was found in 72% of patients and 3% of controls; 88% of patients with bloody diarrhoea, 67% with non-bloody diarrhoea and 55% without diarrhoea were VTEC positive. Seventy-three percent of patients had creatinine clearance > or = 80 ml/min per 1.73 m2, normal blood pressure, no proteinuria and haematuria < 2+ after 1 year of follow-up. One patient died and none had non-renal sequelae. VTEC positivity was significantly correlated with a good outcome, while the absence of diarrhoea and a high total white blood cell count at onset were not predictors of a bad outcome. Household contacts of HUS patients had diarrhoea more frequently than those of the control group, supporting the hypothesis of person-to-person transmission of VTEC infection.

Adolescent↗
PubMed1994

A community outbreak of haemolytic-uraemic syndrome in children occurring in a large area of northern Italy over a period of several months.

From March to October 1993, 15 cases of haemolytic-uraemic syndrome (HUS) in children were detected in a large area of northern Italy, where only 8 cases had occurred in the previous 5 years. Analysis of stool and serum specimens obtained from 14 cases showed evidence of Verotoxin-producing Escherichia coli (VTEC) infection in 13. Serum antibodies to the E. coli O157 lipopolysaccharide (LPS) were found in 8 patients and to the O111 LPS in 2. An O86 VTEC was isolated from another patient. Fourteen children needed dialysis, and 1 died. No obvious epidemiologic link was observed among cases, most of whom lived in small townships. A case-control study did not show an association between HUS and food or exposure to cattle, but suggested an association with contact with chicken coops (OR = 6.5, 95% C.I. 1.2-34.9). However, VTEC were not isolated from stool samples obtained from the chicken coops involved. The risk factors for VTEC infection related to living in rural settlements, including the exposure to live poultry, should be considered in outbreak investigations.

Animals↗
PubMed1994

Community-wide outbreak of hemolytic-uremic syndrome associated with non-O157 verocytotoxin-producing Escherichia coli.

From 20 April through 13 May 1992, 9 children were hospitalized with hemolytic-uremic syndrome in Lombardia, Italy, where only 14 cases of this syndrome had occurred in the preceding 4 years. Cases were scattered in a large area encompassing five provinces, and the source of the outbreak was not identified. Eight patients needed dialysis, and there was 1 death. Seven of the 9 cases were examined for evidence of infection by Vero cytotoxin (VT)-producing Escherichia coli (VTEC). Six children had serum antibodies to the lipopolysaccharide of E. coli O111, and a VT-producing E. coli O111:NM was isolated from stool in 1 case. This is the first outbreak of VTEC infection recognized in Italy and the first associated with an E. coli serotype other than O157:H7.

Antibodies, Bacterial↗