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Biomedical subjects

L Minetti

Publications and source records attributed to L Minetti.

At least 73 records · Page 4Linked to original sources

The changes in plasma diffusible levels and renal tubular handling of magnesium during pregnancy: a longitudinal study.

Magnesium fasting plasma levels (total, PMg, and ultrafiltrable, PMgUF), daily urinary excretion and tubular reabsorption in the fasting state were measured in 14 healthy women along an uncomplicated gestation and compared with the values observed 3-6 months after delivery (C). PMg and PMgUF progressively fell during gestation (from 1.96 +/- 0.14 and 1.38 +/- 0.09 mg/dl in C, respectively, to 1.67 +/- 0.13 (P less than 0.0005) and 1.2 +/- 0.09 (P less than 0.0005) after 17-26 weeks of gestation and to 1.66 +/- 0.10 (P less than 0.0005) and 1.17 +/- 0.08 (P less than 0.0005) after 27 weeks to term). The decrease in PMg and PMgUF was further apparent in an additional group of 46 pregnant women in comparison with 20 sex-matched non-pregnant controls. Urinary Mg excretion remained unchanged throughout gestation, as did glomerular filtered load of PMgUF and tubular Mg reabsorption in the fasting state, due to the increase in GFR. Moreover, urinary Mg excretion per unit GFR (MgE, mg/dlGFR) and fractional excretion of MgUF filtered load (FEMgUF, %) fell (from 41 +/- 25 and 3.0 +/- 0.9 in C, respectively, to 26 +/- 12 (P less than 0.01) and 2.2 +/- 1.0 (P less than 0.05] in the last period, indicating that a greater fraction of filtered Mg was being reabsorbed by renal tubules. There was a significant inverse correlation between PMgUF and GFR in all the periods studied (r = 0.39, P less than 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗

Performance evaluation of cascade filtration with high flow rate recirculating plasma on the secondary filter.

Cascade filtration (CF) has been performed in 67 on-line procedures in 9 normolipidemic patients with paraproteinemic disorders. A modified dead-end technique has been employed, with high flow rate recirculating plasma on the plasma fractionation filter (QD recycled CF), and an albumin-rich, globulin-poor filtrate was reinfused into the patient. Postprocedure recoveries were 81 +/- 15% for albumin, 55 +/- 23% for IgM and 48% for cryocrit, with an increase in A/G ratio from 1.8 to 2.1. An improvement was observed also in antiatherogenic/atherogenic lipoproteins ratio, suggesting a possible use of this technique in the treatment of familial hypercholesterolemia. Plasma primary separation was obtained by centrifugation or by filtration, and no significant differences were observed on subsequent protein fractionation process. An albumin priming of the plasmafractionation circuit accounted for an additional 13% saving in postprocedure level. Different surface area secondary filters have been employed: with larger surfaces, larger volumes were processed without any increase in the waste volume and with reduced need for washouts, but with an additional loss of small molecules possibly due to entrapping onto the membrane.

Blood↗

Steroid-sensitive nephrotic syndrome with mesangial IgA deposits: a separate entity? Observation of two cases.

In minimal-change steroid-sensitive nephrotic syndrome with selective proteinuria, mesangial IgA deposition at immunofluorescence is a very rare finding which has been previously considered a pure coincidence. Two patients, aged 6 and 14 years, respectively, with a steroid-sensitive but frequently relapsing nephrotic syndrome and highly selective proteinuria, exhibited minor glomerular alterations at light microscopy and an immunofluorescence deposition of predominant and diffuse mesangial IgA, confirmed by electron microscopy as dense deposits. The observed syndrome, that is surprisingly identical to sporadic literature reports, can be considered a separate entity or subgroup belonging either to IgA nephropathy or to lipoid nephrosis. In the latter case mesangial IgA could be the marker of an easy relapsing course.

Adolescent↗

Efficacy of a combined treatment with plasma exchange and cytostatics in macroglobulinemia.

Monthly plasma exchange (PE) sessions have been carried out in 3 patients with advanced Waldenström macroglobulinemia, in order to reduce electrophoretic M band under 2g/100 ml. When PE was combined to low doses of cytostatics (n = 18), 3 procedures per session were required to obtain a mean 57.4 +/- 12.3% IgM reduction, from 4.2 +/- 1.2 to 1.7 +/- 0.5 g/100 ml. A mean 61.5 +/- 13.1% IgM reduction, from 5.5 +/- 1.3 to 2.1 +/- 1 g/100 ml, was obtained in 64 procedures carried out as the only therapy in 12 sessions, with 5.3 procedures requirement per monthly session. IgM percent reduction 24 hours after PE was greater with combined treatment (45 +/- 9.7 vs. 28.9 +/- 15.4%; p = 0.001). The advantage of a combined treatment is therefore either a lowered PE requirement or a tapered maintenance cytostatic dosage.

Chlorambucil↗

Immunophenotyping of mononuclear cell infiltrates associated with renal disease.

Twenty-eight frozen renal biopsy specimens with a marked mononuclear cell interstitial infiltrate (MCI) were analyzed with monoclonal antibodies and a biotin-avidin peroxidase technique to define the surface phenotype distribution of the infiltrating cells. Twelve cases were diagnosed as tubulointerstitial nephritis of acute and chronic presentation, of unknown cause in 5 cases or secondary to multiple myeloma or drug reactions. Sixteen cases occurred in primary and secondary glomerulonephritis, 3 cases being associated with lymphoproliferative disorders. The results showed a remarkable heterogeneity of the MCI composition, even in cases with similar clinical and pathological findings. Namely, the T cells accounted for the majority of the infiltrating cells in most cases but a variable predominance of the T cell subsets Leu3 and Leu2 was observed. B cells and monocytes were also prominent in some cases. Such differences in the MCI composition may indicate the activation of different mechanisms of tissue damage, or a different phase of the renal disease. In the three cases of glomerulonephritis associated with lymphoproliferative disorders, the malignant origin of the MCI was demonstrated in one case, while in the remaining cases it was excluded.

Antibodies, Monoclonal↗

Prognostic indicators in idiopathic IgA mesangial nephropathy.

Univariate survivorship analysis of a cohort of 365 patients with idiopathic IgA mesangial nephropathy and at least one year of further observation since the apparent onset (mean = 7.79 +/- 6.19 years; median = 6.16 years) has been performed. Observations for at least one year (mean = 5.05 +/- 3.66; median = 4.08 years) after biopsy was available for 292 of these. One immunohistological, four clinical, and six histological features were associated with increased risk of developing renal failure: (i) older at onset; (ii) no history of recurrent macroscopic haematuria; (iii) proteinuria of more than 1 g/day; (iv) arterial hypertension at the time of biopsy; (v) extent of glomerular obsolescence; (vi) extent of segmental glomerulosclerosis; (vii) presence of interstitial fibrosis; (vii) presence of diffuse intracapillary proliferation; (ix) presence of extracapillary proliferation; (x) presence of segmental thickening of glomerular basement membrane; (xi) extension of IgA deposits to the peripheral capillary loops shown by immunofluorescence. Only features (iii), (v), (vii) and (xi) proved to be independent prognostic indicators in the multivariate survivorship analysis (Cox regression model).

Adolescent↗

Hypertension in man with a kidney transplant: role of familial versus other factors.

Genetic factors are clearly involved in the pathogenesis of essential hypertension in man. In at least three rat models of genetic hypertension it is possible to transplant the hypertension with the kidney. To see whether or not the same is true for humans, we carried out a 2-year retrospective study of 50 selected recipients of a cadaver kidney. We correlated the following factors by multivariate statistical analyses: presence or absence of hypertension in the family of donor and recipients; donor's and recipient's age; mean blood pressure (MBP) and antihypertensive therapy (AHT) score during dialysis; months of dialysis and body surface before transplantation; body weight, plasma creatinine, prednisone dosage and cumulative rejections with MBP and AHT score at various time intervals after transplantation. The results obtained showed that, considering the recipients coming from normotensive families, the AHT score after transplantation was significantly greater (p less than 0.05 1st and p less than 0.01 2nd year) in the patients receiving a kidney removed from donors with hypertensive families than in patients receiving a kidney removed from donors with normotensive families. This difference was not present when the recipients coming from hypertensive parents were considered. AHT score after transplantation is also correlated with AHT score on dialysis (p less than 0.01 1st and 2nd year), body weight (p less than 0.02 1st and p less than 0.01 2nd year), cumulative rejections (p less than 0.025 1st and 2nd year) and inverse MBP after dialysis (p less than 0.025 2nd year).

Adult↗

Is the dialysate fluid source of complement activating factors?

To distinguish between membrane-induced and dialysate-induced mechanism of complement activation attending hemodialysis (HD), the C3a plasma level and blood neutrophil count profiles have been determined during procedures performed with noncellulosic membranes, as PAN and PMMA (with minimal complement-activating potential) and, by comparison, with new cuprophane (that displays the greatest complement-activating potential). Furthermore, PAN and PMMA membranes have been used in 2 other blood purification methods: high efficiency hemofiltration (HEHF), in which there is no dialysate on the other side of the membrane, and hemofiltration without substitution fluid and with reinfusion of dialysis-regenerated hemofiltrate (HWSF), in which the dialysate is separated from the blood circuit by the hemofiltrate circuit. In addition, sequential dialysis-ultrafiltration (UFD) experiments with PAN membranes have been performed, where dialysate was present only in the second part of the procedure. In all the HD and UFD procedures LAL test assays were performed on dialysate at the same times as C3a and neutrophil determinations. Our findings seem to suggest that the dialysate can be a source of complement activating factors; complement activation detectable by C3a plasma levels can ensue when LAL test-positive material is present in the dialysate.

Blood↗

Idiopathic IgA mesangial nephropathy. Clinical and histological study of 374 patients.

Histological features and data on the natural history after 1 to 45 years (mean 6.56 +/- 8.55) of total apparent duration and 1 to 13 years (mean 3.48 +/- 5.04) of post-biopsy follow-up, are reported in 374 patients (mean age, 33.9 +/- 11.9 yrs) with idiopathic mesangial IgA nephropathy, who presented with a history of macroscopic hematuria (56%), recurrent in two-thirds of the patients, or with persistent microscopic hematuria and no previous episodes of gross hematuria (44%). Mesangial cell proliferation ranged from minimal to diffuse. Associated varying degrees of extracapillary proliferation, segmental and global glomerular sclerosis, tubulo-interstitial damage and arteriolar hyalinosis usually correlated with each other and with the extent of mesangial proliferation (P less than 0.05). The actuarial curve of progression to renal death showed a 75% survival after 20 years from apparent onset. Progression to renal failure was more rapid in patients with: an older age at onset (P = 0.0582); male sex (P = 0.0730); no history of recurrent gross hematuria (P = 0.0406); high blood pressure (P = 0.0011); more marked global (P = 0.0007) and segmental (P = 0.0026) glomerular sclerosis; more severe interstitial sclerosis (P = 0.0147); more diffuse and global mesangial proliferation (P = 0.0820); mesangio-parietal pattern at immunofluorescence (P = 0.0778). However, all these parameters showed a poor predictive value if applied to any single patient.

Adolescent↗

Influence of technical factors and different immunosuppressive regimens on kidney graft survival. Retrospective analysis on 300 kidney transplants.

300 patients underwent kidney transplantation. Uretero-neocystostomy was performed by means of the Politano-Leadbetter technique in the first 185 patients and direct ureterovesical anastomosis in the other 115 patients. Immunosuppression included conventional therapy (steroids, antilymphocyte globulins, azathioprine) and the association cyclosporine A and steroids. Retrospective analysis on these 300 patients indicates that the improved 1 year graft survival rate (85% vs 64%) we observed in the latest years has depended to the same extent, on improved surgical technique and on advent of cyclosporine A in our therapeutic protocols. Cyclosporine A at low starting doses immediately adjusted on whole blood trough levels (200-400 ng/ml) proved to be superior to other therapeutic schedules reported in this study (1-year graft survival rate: 94% vs 84%-73%). Direct ureterovesical anastomosis was characterized by a net reduction of urologic complications (2.5% vs 9.7%).

Antilymphocyte Serum↗

Haemofiltration without substitution fluid.

Haemofiltration at its best is able to give excellent clearances of solutes in a wide molecular weight range, but the need of large amounts of reliable substitution fluid makes this technique too expensive for more widespread application. In order to give an 'adequate' treatment by a safe, well tolerated, effective and comparatively cheaper method, haemofiltration without substitution fluid (HWSF) has been carried out. This method, consisting of the regeneration of appropriate amounts of pure convected plasma water by highly permeable, high surface area dialysis membranes, has been utilised for several months in four patients, with encouraging clinical results.

Adult↗

Vitamin D metabolites and osteomalacia in the human Fanconi syndrome.

Experimental evidence suggests that renal 1 alpha-hydroxylase activity is impaired in Fanconi syndrome. We have evaluated plasma vitamin D metabolites in five patients with Fanconi syndrome, three of whom had metabolic bone disease; plasma 1,25(OH)2D3 was low in the three patients with bone disease, and normal in the two patients without a bone mineralisation defect. The data supports the hypothesis that renal 1 alpha-hydroxylase activity may be impaired in human Fanconi syndrome, and that altered vitamin D metabolism may contribute to the pathogenesis of metabolic bone disease in Fanconi syndrome.

Aged↗

Lupus nephropathy and pregnancy. A study of 26 pregnancies in patients with systemic lupus erythematosus and nephritis.

We describe 26 pregnancies in 19 patients with lupus nephritis. There were 4 spontaneous abortions, 2 therapeutic abortions, 4 stillbirths and 1 neonatal death. 10 deliveries were preterm and 2 fetuses were small for gestational age. 8 pregnancies were not accompanied by change of renal symptoms. Mild signs of renal involvement appeared during pregnancy in 4 patients. 6 patients showed an increase in proteinuria already present before pregnancy without renal function deterioration. A moderate worsening of renal function was observed in 3 patients. 4 patients, 3 of whom had an apparent onset of systemic lupus erythematosus during pregnancy, developed anuric acute renal failure after delivery or after late spontaneous abortion. 2 of them died from sepsis and disseminated intravascular coagulation while 2 had complete recovery of renal function. A high rate of complications was observed in patients not adequately treated during pregnancy. Renal biopsy before gestation was not predictive of the outcome of nephropathy during pregnancy, and change of histology in repeated biopsies was frequently observed.

Abortion, Spontaneous↗