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Biomedical subjects

C Brunati

Publications and source records attributed to C Brunati.

At least 19 recordsLinked to original sources
PubMed1997

Abnormal reabsorption of Na+/CI- by the thiazide-inhibitable transporter of the distal convoluted tubule in Gitelman's syndrome.

Eleven patients with Gitelman's syndrome and 23 controls underwent acute administration of the thiazide diuretic hydrochlorothiazide and/or the loop diuretic furosemide (FUR) in order to indirectly evaluate the activity of the two electroneutral Na+/Cl(-)-reabsorptive systems of the distal nephron, namely the thiazide-sensitive Na+-Cl- symporter of the distal convoluted tubule and the FUR-sensitive Na+-K+-2Cl- symporter of the loop of Henle. The patients were characterized by hypokalemia, mild metabolic alkalosis, hypomagnesemia, hypocalciuria, and reduced free water generation during maximally diluted diuresis which indicated reduced distal nephron NaCl reabsorption. The plasma Na and Cl levels were similar in patients and controls. Hydrochlorothiazide induced a significantly lower increase of urinary Na and Cl excretions in 6 patients with Gitelman's syndrome than in 6 controls, indicating reduced NaCl reabsorption by the thiazide-sensitive Na+/Cl- symporter of the distal convoluted tubule in Gitelman's syndrome. FUR induced a slightly higher increase of urinary Na and Cl excretions in 11 patients with Gitelman's syndrome than in 17 controls, in keeping with reduced NaCl reabsorption in tubular sites past the loop of Henle during FUR effect or increased NaCl reabsorption in the loop itself (as a compensatory mechanism for NaCl-reabsorptive defect in the distal convoluted tubule) or both. Our results confirm that the functional activity of the renal thiazide-sensitive Na+-Cl- cotransporter (but not of the FUR-sensitive carrier) is deficient in patients with Gitelman's syndrome, in keeping with the recently described genetic link between the syndrome and a wide variety of nonconservative mutations of the gene encoding the protein; it is suggested that dynamic studies with diuretic administration may be of diagnostic help in this condition.

Adolescent↗
PubMed1996

Effects of desferrioxamine therapy on chronic disease anemia associated with rheumatoid arthritis.

OBJECTIVE: To investigate the effects of desferrioxamine (DFO) infusion on chronic disease anemia (CDA) of rheumatoid arthritis (RA) by evaluating interleukin-6 (IL-6) and erythropoietin (EPO) production. PATIENTS AND METHODS: Five patients with RA and CDA (group I) were treated with DFO, 500 mg daily, through a continuous 10-h subcutaneous infusion 5 days a week for 4 weeks. One month after withdrawal, DFO was resumed in all five group I patients (group II) with an increase to 1 g daily following the previous treatment schedule. Clinical and laboratory parameters were evaluated weekly during the two study periods. Serum EPO was measured by radioimmunoassay. IL-6 was detected by the enzyme-linked immunoabsorbent assay method. RESULTS: No significant variations in hematological parameters, IL-6 or EPO levels were observed in group I patients. After 1 week of DFO 1 g daily, reticulocyte counts and EPO improved significantly. Hemoglobin and hematocrit rose significantly after 3 weeks of 1 g daily DFO therapy. Four weeks after DFO withdrawal, EPO, reticulocyte counts, hemoglobin and hematocrit returned to baseline levels. A significant improvement in the clinical parameters of disease activity was observed, particularly in group II patients. CONCLUSION: DFO improves CDA in RA patients. The beneficial effects on erythropoiesis seem to be related to improved EPO responsiveness to the anemia.

Anemia↗
PubMed1996

Inhibitors of myo-inositol monophosphatase, ATCC 20928 factors A and C. Isolation, physico-chemical characterization and biological properties.

During the course of a screening program for inhibitors of myo-inositol monophosphatase we fermented the strain ATCC 20928, a known producer of L-671,776. We now show that this strain produces a complex of at least three sesquiterpenic compounds, L-671,776 (termed factor B) and two structurally related substances, termed factors A and C. Both factors A and C, like L-671,776, exhibited inhibitory activity against myo-inositol monophosphatase. Six other fungi producing the above mentioned compounds were also isolated and taxonomically characterized.

Benzofurans↗
PubMed1994

Calcium metabolism and calciotropic hormone levels in Gitelman's syndrome.

In 10 adult patients (5 females and 5 males, aged 13-57 years) with Gitelman's syndrome (GS, or hypocalciuric variant of Bartter's syndrome, characterized by chronic renal hypokalemia, metabolic alkalosis, hypomagnesemia and hypocalciuria), parameters of Ca metabolism and calciotropic hormone levels were evaluated. Hypocalciuria was associated with a marked reduction of fractional excretion of ionized Ca (as compared with 16 sex- and age-matched controls) and normal filtered Ca load, as indicated by serum ionized Ca; hypocalciuria was thus the result of increased tubular reapsorption of filtered Ca. Plasma levels of total Ca were increased in GS (p < 0.02) but ionized Ca was not different from controls; percent fraction of ionized to total Ca was reduced, indicating increased Ca complexation and/or protein binding, possibly related to a metabolic alkalosis-induced increase of plasma albumin affinity for Ca. Levels of plasma total protein and albumin were similar in GS and controls. Despite similar ionized Ca levels, PTH1-84 was lower in GS than in controls, indicating abnormal ionized Ca-PTH relationship, possibly related to hypomagnesemia. Plasma 1,25(OH)2D levels were not different in GS and in controls, and intestinal fractional Ca absorption (evaluated with a simplified method using stable Sr as a tracer) was not reduced in 4 patients. However, in 5 patients bone mineral density in the forearm (3 patients) or lumbar spine (2 patient) was normal. Thus, despite chronic hypocalciuria and normal 1,25(OH)2D levels, Ca 'thesaurosis' does not occur in bones of GS patients; a likely explanation is that, despite normal 'fractional' intestinal Ca absorption, 'net' intestinal absorption is reduced, due to increased intestinal Ca secretion.

Adolescent↗
PubMed1993

Clinical relevance of fractionation characteristics in cascade filtration.

Plasmapheresis performance is improved in the treatment of hyperviscosity syndromes with one of the several cascade filtration techniques (CF), intended for plasma fractionation and reinfusion of albumin-enriched plasma filtrate to the patients, avoiding the need for exogenous reinfusion solutions. A retrospective open analysis of 103 CF, performed by dead-end mode, in 14 patients with macroglobulinemia, cryoglobulinemia, multiple myeloma and other diseases, has been performed. Protein fractions removals have been calculated, normalized to the treatment of one plasma volume, compared in different macromolecular diseases and according to the different plasma fractionators employed. [table: see text] Protein removal is partially dependent of the surface area of the fractionator, but a wide variability has been reported, mainly depending on the underlying macromolecular disease.

Blood Viscosity↗
PubMed1992

Uremic inhibitors of erythropoiesis: a study during treatment with recombinant human erythropoietin.

The effects of increasing amounts of uremic sera (US) on the growth of erythroid progenitor cells [burst-forming unit erythroid (BFU-E)] collected from peripheral blood of normal subjects were evaluated to assess the potential role of uremic inhibitors of erythropoiesis during a treatment with recombinant human erythropoietin (r-HuEpo). US were collected from 8 patients on regular dialysis with marked anemia (Hb 6 +/- 0.5 g%) before and after a treatment with high doses of r-HuEpo (from 300 to 525 U/kg/week). Standard cultures for BFU-E were performed in alpha-metylcellulose with fetal calf serum (FCS) and 4 U/ml of r-HuEpo (Cilag, Ortho). In successive cultures, US were added at increasing amounts to the standard culture in order to assess a possible inhibitory effect on BFU-E growth. Finally, in order to assess a possible lack of stimulatory factors, we partially substituted FCS with US. The addition of US collected either before or after therapy with r-HuEpo to the standard culture had no effect on the growth of BFU-E. Vice versa, the number of cultured BFU-E decreased when FCS was partially substituted with US collected before r-HuEpo. This effect was not evident when FCS was partially substituted with US collected after r-HuEpo. No significant differences were recorded in the tested sera collected before and after therapy considering erythropoietin levels and amino acid levels. We hypothesized that some other factors with erythropoietic stimulatory activity (burst-promoting activity?) may be deficient in uremic patients with marked anemia and can be induced during therapy with r-HuEpo.

Adult↗
PubMed1992

Circulating burst-forming-unit erythroid and the responsiveness to recombinant human erythropoietin in patients on regular hemodialytic treatment.

The dose of recombinant human erythropoietin (r-HuEpo) required to correct anemia of end-stage renal disease varies among patients. The possible factors that interfere with the responsiveness to r-HuEpo were not completely known. In 32 patients on regular hemodialytic treatment with marked anemia (Hb 5.6 +/- 0.7 g/dl), we evaluated circulating erythroid progenitor cells [burst-forming-unit erythroid (BFU-E)], erythropoietin, ferritin, folate and 1-84-parathormone levels before r-HuEpo therapy. In 12 patients, the aluminum levels after deferoxamine were also evaluated. The possible correlation between these factors and the response to r-HuEpo therapy was then evaluated. The number of circulating (c) BFU-E was highly variable (521 +/- 447 colonies/ml of blood; normal level 742 +/- 192) and does not correlate with erythropoietin, ferritin, folate, 1-84-parathormone or aluminum levels. A direct correlation between basal cBFU-E and the responsiveness to r-HuEpo therapy was recorded while no correlation was found with the other analyzed parameters. We hypothesized that low basal cBFU-E (interleukin-3 deficiency?) could reduce the response to r-HUEpo because of failure of this hematopoietic stem cell compartment to replenish the pool of more mature erythropoietic progenitor cells during the phase of accelerated maturation induced by r-HuEpo.

Anemia↗
PubMed1990

Erythrocyte ferritin in patients on chronic hemodialysis treatment.

Serum ferritin (SF) and erythrocyte ferritin (EF) were evaluated in 35 patients on chronic hemodialysis treatment (CHD), in 45 healthy subjects and in 22 nonnephropathic females with iron deficiency anemia. Twenty-five CHD patients with basal SF less than 500 micrograms/l were treated orally with 200 mg of Fe2+ for 2 months and the positive (hemoglobin increase greater than 1 g/dl) or negative response to the therapy was correlated to the basal levels of SF and EF. Three groups of CHD patients could be defined on the basis of their basal SF levels (hypo-, normo- or hyperferritinemic). Nine patients with increased SF levels had also EF levels significantly higher than the other CHD patients and controls since they were probably iron-overloaded. In the other 2 groups of CHD patients, EF levels were significantly higher than in controls for each level of SF probably because of the reduced utilization of iron by uremic bone marrow. Among the 25 treated CHD patients, only 5 responded to the therapy: 3 were hypoferritinemic while the other 2 responders had basal SF within the normal range. Four hypoferritinemic patients did not respond to the therapy. Four out of five responders had the lowest EF levels among CHD patients. EF measurement could be an important and useful test in detecting the presence of an iron deficiency erythropoiesis in CHD patients.

Adult↗
PubMed1989

Fluorocytometric analysis of anti-HLA class 2 autoantibodies in patients with lupus nephritis.

Systemic lupus erythematosus (SLE) patients are known to produce a variety of autoantibodies (AAb), some of which may be directed against immunocompetent cells. Anti-B cell autoimmunity may encompass reactivity against HLA-class 2 molecules, which are also expressed on kidney tissue. We studied 15 patients with moderate to severe renal involvement and 5 lupus patients with no clinical renal disease, in order to detect the presence of anti-HLA class 2 AAb. Flow cytometry was employed in an inhibitory assay using patient sera, autologous cells and two anti-class 2 monoclonals, to establish the specificity of anti-B cell AAb. Seven out of 15 nephritis patients had detectable anti-class 2 AAb with an epitopic heterogeneity, as demonstrated by different degrees of inhibition on the binding of non-overlapping monoclonals. The specificity of the reaction was confirmed by the lack of inhibition of non-class 2 antibody binding. The presence of such AAb was not correlated with disease activity but with the presence of a diffuse proliferative glomerulonephritis on renal biopsy. Anti-class 2 AAb may be a marker of SLE diffuse proliferative nephritis.

Adolescent↗
PubMed1988

Different cascade filtration operating modalities in clinical use.

Cascade filtration (CF) can be performed in either the single-pass or dead-end configuration. The distinction, as predicted by experimental models, is that solute removal is lower but constant in the former, and higher but variable with the quantity of filtrate in the latter. Moreover, unpredictable plugging reduces permeability during operation. It is therefore unclear which configuration is preferable in clinical use. In four cryo- and three macroglobulinemic patients, the data of 10 dead-end CF (QP) and 11 modified single-pass CF with high flow rate recycling plasma (QD) were compared. Both groups had similar starting values. Centrifugal primary plasma separation was performed. No exogenous reinfusions were used. Either 0.8 and 1.2 sq.m. surface secondary filters were employed. The ratio of plasma processed to patients' plasma volume was 1.1 +/- 0.3 in QP, and 0.94 +/- 0.09 in QD. The mean percentage removals of albumin, IgG and IgM respectively were 25.8 +/- 9, 32 +/- 17 and 47.5 +/- 26% in QP, 30.5 +/- 12, 40.5 +/- 19 and 48 +/- 17.5% in QD: albumin vs IgM p less than 0.025 in QP and p less than 0.02 in QD. A/G ratio increased from 1.6 +/- 0.5 to 2.06 +/- 0.6 in QP, and from 1.5 +/- 0.3 to 1.7 +/- 0.3 in QD. Plugging occurred in both groups, requiring 2.3 +/- 1.8 washouts/run in QP vs 1.5 +/- 1.2 in QD. IgM removal was comparable. Removal of albumin and IgG was slightly higher in QD. Similar performances can be obtained with either technique in clinical use, provided an adequate fractionation surface is available.

Adult↗