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M Bonomini

Publications and source records attributed to M Bonomini.

At least 37 records · Page 2Linked to original sources
PubMed1999

Leukocyte adhesion molecules and leukocyte-platelet interactions during hemodialysis: effects of different synthetic membranes.

Membranes made from synthetic polymers, in general, are considered as being biocompatible membranes and tend to be treated as a homogeneous group. However, all of these membranes have multiple and different characteristics that may contribute to interactions with blood components. As a consequence, the biocompatibility profile of synthetic membranes may vary. In the present cross-over study, we examined by flow cytometry the effects (expressed as % change from predialysis values) of three different synthetic polymers (polysulfone, PSF; polyacrylonitrile-co-sodium methallyl sulfonate, AN69; ethylenevinylalcohol, EVAL) on the expression of leukocyte adhesion molecules (CD11b/CD18, CD15s) and the interactions between leukocytes and platelets under conditions of routine clinical use. For neutrophils, a statistically significant difference was found in CD15s expression for EVAL as compared to AN69 (p<0.05) and in CD11b/CD18 expression for PSF as compared to both EVAL (p<0.01) and AN69 (p<0.05). No difference between membranes was found on the expression of such adhesive molecules on monocytes. Significant differences in platelet-neutrophil (but not in platelet-monocyte) coaggregate formation were observed between PSF and both EVAL (p<0.001) and AN69 (p<0.01). Reactive oxygen species production by neutrophil population during hemodialysis was significantly different between each pair of synthetic polymers (PSF vs EVAL, p<0.001; PSF vs AN69, p<0.001; AN69 vs EVAL, p<0.05). Our data demonstrate that in terms of leukocyte adhesion receptors and platelet-leukocyte interactions, the biocompatibility profile of the synthetic membranes polysulphone, AN69 and EVAL shows many similarities but also several significant differences. Our results support the concept that biocompatibility evaluation of each membrane should be based exclusively on data generated by that membrane in order to avoid errors based on assumptions about group characteristics.

Acrylic Resins↗
PubMed1998

Clinical use of profiled hemodialysis.

The new population on dialysis today consists mainly of high risk patients (the elderly, diabetics, etc.) with high cardiovascular scores, and such vascular pathology is the most important predisposing factor for the occurrence of a frequent intradialytic clinical complication, vascular instability syndrome, which covers a range of clinical problems. Recently a new dialysis technique, profiled hemodialysis (PHD), has been set up and proposed for routine use. PHD consists of the clinical use of preestablished individual dialysis profiles aimed at antagonizing the changes in intradialytic plasma osmolarity by continuous modulation of dialysate sodium concentration throughout the whole extracorporeal session. In particular, PHD aims at reducing the fall of plasma osmolarity in the first half of the session (when it is higher) by reducing the sodium removal rate through increasing its dialysate concentration while taking into account the desired individual sodium balance to be reached at the end of the session. In this work, we report clinical experience with PHD compared to standard hemodialysis with constant sodium dialysate (SHD) in terms of its efficacy to maintain a more stable intradialytic blood volume (BV) and more stable hemodynamics. The PHD used in this work has been implemented by a mathematical model for computing the individual dialysate sodium profile which we have recently validated (Ursino M, Coli L, La Manna G, Grilli Cicilioni M, Dalmastri V, Guidicissi A, Masotti P, Avanzolini G, Stefani S, Bonomini V. A simple mathematical model of intradialytic sodium kinetics: "in vivo" validation during hemodialysis with constant or variable sodium. Int J Artif Organs 1996;19:393-403.). Eleven uremic patients affected by hypotension at the beginning of dialysis treatment were studied. Each patient first underwent an SHD treatment and 1 week later a PHD treatment. The 2 extracorporeal sessions (one on SHD and the other on PHD) were performed in each individual patient under identical operative conditions including the sodium mass removal by the end of the session and the ultrafiltration rate. The crit line and Doppler echocardiography were used to determine BV, cardiac output (CO), and stroke volume (SV) throughout the sessions. The mean blood pressure (MBP) and heart rate (HR) were simultaneously monitored. PHD was associated with a more stable intradialytic BV and more stable hemodynamics compared to SHD. The higher stability of BV and cardiac function (in terms of SV and CO maintenance) which was obtained above all in the first half of the PHD session was associated with a higher stability of the MBP and the HR. This resulted in an enhancement in cardiovascular tolerance to ultrafiltration throughout the session in all tested patients. In contrast, SHD in the same patients was characterized by early significant changes in BV and cardiovascular parameters resulting in a significant decrease of the MBP and a significant increase of the HR throughout the session and also 1 h after the end of dialysis. Our results indicate that PHD may represent an efficient approach for the treatment of patients suffering from intradialytic vascular instability. If long-term clinical practice confirms the efficacy of PHD in controlling dialysis intolerance symptoms, it will have great scope as a routine procedure.

Aged↗
PubMed1998

Serum levels of soluble adhesion molecules in chronic renal failure and dialysis patients.

Besides cell-bound adhesion molecules, which are of fundamental importance to a large number of physiological and pathological processes, soluble forms of adhesion molecules have been detected in the circulating blood in recent years. Circulating soluble adhesion molecules appear to be biologically active, and raised levels have been reported in a variety of disorders. In the present study, we used ELISA to measure the serum levels of four soluble adhesion molecules in 23 undialyzed patients with chronic renal failure (CRF), 13 patients on continuous ambulatory peritoneal dialysis (CAPD), 17 on chronic hemodialysis (HD) and 18 healthy controls having a similar mean and distribution of ages. The investigated soluble (s) molecules included intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1 (sVCAM-1), sE-selectin and sP-selectin. sICAM-1 was found to be elevated in patients with CRF (p < 0.05), on CAPD (p < 0.02) and HD (p < 0.0001) compared with the controls but levels did not differ between the three patient groups. The higher sVCAM-1 values found in CRF (p < 0.02), CAPD (p < 0.05) and HD (p < 0.0001) as compared to controls again failed to differentiate the three groups of patients. Soluble E-selectin was also raised in the three groups (p < 0.0001) with no difference between them. Increased sP-selectin was found in CRF (p < 0.05), CAPD (p < 0.02) and in HD patients (p < 0.0001) compared to controls, and levels in HD were significantly higher (p < 0.02) than in CRF patients. Predialysis serum molecule levels did not differ between HD patients treated with cuprophan or with polyacrylonitrile dialyzers. HD sessions with both dialyzers had no effect on sICAM-1, while a decrease (p < 0.02) in sP-selectin was found after dialysis with cuprophan. In undialyzed patients with CRF, regression analysis showed a strong linear correlation between serum creatinine and serum levels of each soluble molecule. These results demonstrate that serum levels of soluble adhesion molecules ICAM-1, VCAM-1, E-selectin and P-selectin are elevated in both undialyzed patients with CRF and patients on CAPD or HD. The elevated serum levels of these proteins probably reflect inadequate clearance as well as enhanced synthesis/release.

Adult↗
PubMed1998

Platelet-neutrophil interactions during hemodialysis: a proposed biocompatibility approach.

Platelet interaction with neutrophils may occur to a significant degree during hemodialysis (HD). We have recently shown that the enhanced neutrophil reactive oxygen species (ROS) production during the early phase of HD with cuprophan (CUP) is sustained by neutrophils which have bound platelets through P-selectin (CD62P). The evaluation of platelet-neutrophil interactions during dialysis offers the novel aspect of cell-cell interactions as a new parameter for studying the biocompatibility of dialyzer membranes. By the use of flow cytometry techniques, the present study was set up to analyze intradialytic platelet-neutrophil coaggregate formation and neutrophil ROS (hydrogen peroxide) production from 6 HD patients each dialysed with CUP, cellulose diacetate (CDA), polymethylmethacrylate (PMMA), and polyacrylonitrile (PAN) in a cross-over clinical trial. Platelet-neutrophil coaggregate formation (percentage of neutrophil cells positive for CD62P) and ROS production by neutrophils (total population; CD62P+ cells; CD62P- cells) were determined before HD and after 10', 20'and 40'. CD62P+ neutrophils significantly increased during HD with CUP (10', 20', 40'), PMMA (20') and CDA (20), while no change was observed with PAN. The difference between CUP and the other membranes was significant at 10', 20' and 40'; at 20', PMMA vs PAN p<0.005. ROS production by total neutrophil population significantly increased with CUP (10', 20), PMMA (20) and CDA (20'). The increase with CUP was higher at 10' when compared to CDA (p<0.020) or PAN (p<0.005), and at 20' versus the other three membranes; at 20' PMMA vs PAN p<0.005. Only neutrophils gated in neutrophil-platelet coaggregate areas (CD26P+ neutrophils) produced hydrogen peroxide. ROS production by CD62P+ neutrophils significantly increased with CUP (10', 20), PMMA (20') and CDA (20'). The increase with CUP was significantly (p<0.0002) higher than the other three membranes at 10' and 20'; at 20', PMMA vs PAN p<0.02. With each membrane, ROS production by CD62P- neutrophils showed no significant change at any time point during HD. The results of the present study indicate that interactions between platelets and neutrophils can mediate some pathophysiological abnormalities associated with hemodialysis treatment. Our data show that cellulose diacetate, a modified cellulosic membrane, exhibits a biocompatibility profile in terms of platelet-neutrophil interactions improved as compared to the parent cellulose membrane and comparable to that of some synthetic membranes. Our data also show that there is considerable variability in the biocompatibility of synthetic membranes. Though cellulosic membranes are generally considered as being less biocompatible than synthetic membranes, our results indicate that classification of membranes by biocompatibility is more complex than a simple division into cellulosic and synthetic membranes, especially with the advent of modified cellulosic membranes.

Acrylic Resins↗
PubMed1997

Neutrophil reactive oxygen species production during hemodialysis: role of activated platelet adhesion to neutrophils through P-selectin.

Platelet interaction with leukocytes can occur to a significant degree during hemodialysis, but it remains to be determined what pathophysiological consequences stem from the intradialytic formation of platelet-leukocyte coaggregates. By the use of flow cytometry techniques, this study was set out to analyze intradialytic platelet-neutrophil coaggregate formation and neutrophil hydrogen peroxide production from 10 end-stage renal disease patients each dialyzed with cuprophane and polyacrylonitrile membranes. Platelet-neutrophil coaggregates increased during dialysis with cuprophane, whereas no changes occurred with polyacrylonitrile membranes. Dialysis with cuprophane, unlike that with polyacrylonitrile, also resulted in a significant increase in neutrophil hydrogen peroxide production 10 min after dialysis initiation which persisted at significantly higher levels than predialysis values through the first 20 min. We found that the increased hydrogen peroxide production by neutrophils essentially occurred in concomitance with neutrophil-platelet coaggregation. Intracellular fluorescence representing hydrogen peroxide formation significantly increased through the first 20 min of cuprophane dialysis in neutrophils aggregated to platelets. By contrast, no change occurred in neutrophils not aggregated to platelets. Neutrophils which had formed aggregates with platelets produced higher hydrogen peroxide levels, as assessed by significantly higher fluorescence values, than non-aggregate-forming neutrophils at all time points tested. The phenomenon was duplicated in vitro when ADP-activated normal platelets were incubated with neutrophil cells but was largely inhibited when ADP-activated platelets were treated with anti-P-selectin antibody before incubation with neutrophils. These results strongly suggest that platelet-neutrophil aggregates occurring during hemodialysis, representing cell-cell interactions with pathophysiological effects, may serve as a new parameter to assess biocompatibility.

Adenosine Diphosphate↗
PubMed1996

Thyroid function and plasma selenium in chronic uremic patients on hemodialysis treatment.

It has been shown recently that Selenium (Se), an essential trace element for humans, is involved in the regulation of thyroid function, since the enzyme that catalyzes the liver conversion of the thyroid hormone T4 to the more active form T3 is a selenoenzyme. In chronic uremic patients, low blood Se levels as well as thyroid function abnormalities are often found. The present study was carried out to verify whether any correlation exists between Se levels and thyroid function, and to evaluate possible changes in hormonal pattern during Se supplementation in 10 chronic uremic patients on hemodialysis (HD) treatment. Se was supplemented orally as sodium selenite over six consecutive months. Basic plasma Se levels were significantly lower in patients than in normal controls. Right from the start of Se supplementation, plasma Se concentration promptly normalized and leveled off in the normal range throughout the study. Significant increase of FT3 and reduction of TSH levels were detected during Se supplementation. In Se-supplemented patients, a significant direct correlation was also found between reverse T3 (rT3) and TSH, and a significant inverse correlation was found between Se and TSH. Our results suggest that Se deficiency in chronic uremic patients represents a factor influencing the thyroid function and that the Se status should be determined in the evaluation of thyroid metabolism in these patients.

Administration, Oral↗
PubMed1996

Cell-associated adhesion molecules as early markers of bioincompatibility.

BACKGROUND: Transient nature of adhesive interactions occurring during cell margination is mainly dependent on expression of selectins which are shed by activated cells. This shedding in the circulation may play an important role as anti-inflammatory mediator. Haemodialysis is also associated with P-selectin (CD62P)/sialyl-Lewis(x) (CD15s) interactions which mediate platelet-leukocyte coaggregation. We further investigated the mechanisms underlying leukocyte margination during haemodialysis. METHODS: CD15s, CD11b and CD61 expression on circulating leukocytes from patients dialysed on synthetic membranes (modified polyacrylonitrile (SPAN), polysulphone (PS), and polyacrylonitrile (AN69) was assessed by cytofluorometry in a prospective crossover trial. We measured plasma levels C3a/C3a desArg, soluble CD62P, and CD62E molecules obtained from patients and healthy individuals. RESULTS: Expression of CD11b and CD15s was upregulated on neutrophils from patients dialysed with SPAN and PS membranes during the dialysis session. A significant negative correlation was found between the expression of CD11b or CD15s molecules and neutrophil counts as well as between CD15s expression and monocyte counts during haemodialysis. As assessed by CD61 expression on leukocytes, we observed that platelets bound significantly onto both neutrophils and monocytes during dialysis with both membranes. A significant positive correlation was found between the expression of CD11b molecules and the percentage of CD61+ monocytes counts during SPAN and PS dialysis. We found a significant increase of soluble CD62P in plasma samples obtained from haemodialysed patients before the dialysis session as compared to the levels detected in plasma from healthy individuals. CONCLUSIONS: This study documents a major role of CD15s, CD11b, CD61, CD62P molecules in the transient leukocytes activation and margination during haemodialysis on synthetic membranes despite their low complement-activating properties.

Adult↗
PubMed1996

Low-dosage ibopamine treatment in progressive renal failure: a long-term multicentre trial.

A multicentre trial (11 nephrology centres) was carried out to test the effects of ibopamine, an orally active dopamine-like drug, on the progression of chronic renal failure. For a 2-year period 189 chronic renal failure patients (serum creatinine level 1.5-4.0 mg/dl) were observed. They were homogeneous for basic nephropathy, degree of residual renal function, blood pressure, and proteinuria. The patients were randomly divided into two groups: 96 took ibopamine at a dosage of 100 mg/day (group A) and 93 served as controls (group B). All were on a low-protein diet (mean 0.8 g/kg body weight). By the end of the observation period, the rate of decrease of the renal function indexes in time proved significantly slower (1.8 times) in group A than in group B. The survival curves for renal function (pre-established end points were creatinine level increases equal to or > 20% and equal to or > 40% of the basal values) proved significantly better (p < 0.02 and p < 0.002 respectively) in group A than in group B. The mean plasma creatinine values rose by 17% in group A and by 36% in group B. The creatinine clearance decreased by 5% in treated patients and by 14% in the controls. Statistical analysis ruled out any possible centre effect. The trial suggests that low-dosage ibopamine administration may be used as a valid and safe pharmacological adjunct for retarding the progression of renal failure in patients with mild or moderate chronic renal impairment.

Adolescent↗
PubMed1996

Geographic factors and plasma selenium in uremia and dialysis.

The importance of selenium (Se) as an essential trace element for man has been increasingly recognized. Blood Se levels in chronic uremic patients are frequently reported to be lower than in controls. Definitive determination of the Se status in uremic patients, however, is hampered by the wide range of blood Se content in humans from different parts of the world. The present study was designed to assess and compare the Se status in two European populations from Rostock (Germany) and Chieti (Italy). Plasma Se levels were evaluated in healthy controls, chronic renal failure nondialyzed patients (CRF) and hemodialysis patients (HD). All Se determinations were performed in a single laboratory. The Se concentration was significantly higher (p < 0.005) in Italian healthy controls than in German healthy controls. In contrast, Se levels were similar in both CRF and HD patients from both cities. In both countries, the Se concentration in CRF and HD patients was significantly lower (p < 0.001) than in their corresponding controls, but no difference between CRF and HD was found. CRF and HD patients from the two countries showed quite similar laboratory and anthropometric data. In CRF patients in Chieti, a significant (p < 0.05) negative correlation between plasma Se and serum creatinine was found. In both HD groups, the length of time on HD and type of membrane dialyzer used did not influence the Se status. A significant positive correlation (p < 0.01) between Se levels and the protein catabolic rate was found in both HD groups. Uremia seems to be a strong factor which overrules the difference in Se levels that is present in healthy adults from different European countries. Uremia in itself may influence and level the Se concentration in patients with geographic diversity.

Adult↗
PubMed1996

A new polymethylmethacrylate membrane for hemodialysis.

High molecular weight (MW) solutes are not removed during conventional hemodialysis (HD), and their accumulation is thought to play a role in some long-term HD complications (anemia, bone and joint pain, neuropathy, itching). The present trial was conducted to evaluate the removal capacity during in vivo HD of a new polymethylmethacrylate (PMMA) membrane (Filtryzer BK-F, 1.3 m2) compared to conventional PMMA (BK-P, 1.6 m2) and to cellulose acetate (CA, 1.3 m2). BK-F dialyzers, with a pore size of 100 A degrees and 62% porosity, are designed to remove high MW substances. Ten stable anuric RDT patients (53 +/- 13 years) were treated for one week with each membrane in a randomized sequence. Plasma concentrations of creatinine, BUN and beta 2-microglobulin (beta 2-M) were measured before (b) and after (a) HD to determine the reduction rate for these substances (%). Beta 2-M concentration after HD was corrected for changes in distribution volume. Samples of spent dialysate were collected after 3 minutes, 120 minutes and at the end of HD sessions, and appropriately treated and concentrated for HPLC analysis. The reduction rate for BUN and creatinine was similar for the 3 membranes. BK-F showed a higher beta 2-M reduction rate than BK-P (p < 0.005) or CA (p < 0.0001). HPLC analysis of dialysate showed prevalent peaks < 4 kilodaltons (kDa) throughout HD for BK-P and CA. Solutes > 10 kDa were infrequently detected. Peak profile during HD with BK-F was quite different, showing a predominant peak > 50 kDa which also included albumin. However, albumin loss significantly decreased after 120 minutes and at the end of dialysis compared with the 3-minute values, and was lower than that reported in CAPD patients. With BK-F a peak of MW > 500 kDa was also detected which previous studies indicated as a range characterized by the presence of erythropoiesis inhibitors. Use of the BK-F membrane in HD could afford satisfactory removal of high MW substances, thereby preventing or controlling some long-term HD complications such as anemia or beta 2-M amyloid formation.

Adult↗
PubMed1995

Hemodialysis with regenerated cellulosic membranes does not reduce plasma selenium levels in chronic uremic patients.

Selenium (Se) is considered an essential and very important trace element for humans. Se blood levels are frequently low in end-stage renal disease (ESRD) patients, but very little has been established concerning the mechanisms that could modify Se status in uremia, including a supposed dialysis-mediated Se depletion. In order to verify whether hemodialysis (HD) can induce a loss of Se, thereby leading or contributing to a low plasma Se concentration, we investigated the effect of HD procedure with the most commonly used regenerated cellulosic membrane (Cuprophan) on plasma Se levels in 20 uremic patients on HD for 62.5 +/- 49.4 months. Plasma Se levels were also determined in 15 chronic renal failure (CRF) nondialyzed patients and in 28 age-matched healthy controls. Se concentration was determined by atomic absorption spectrophotometry. Plasma Se levels of both HD patients (61.3 +/- 8.5 micrograms/L) and CRF nondialyzed patients (56.4 +/- 10.1 micrograms/L) were significantly lower than in normal subjects (78.3 +/- 9.7 micrograms/L, p < 0.001). In CRF nondialyzed patients, a significant (p < 0.05) negative correlation was found between the plasma Se concentration versus serum creatinine values. Within the HD group, plasma Se levels significantly increased after the HD procedure (72.8 +/- 17.2 micrograms/L, p < 0.02) together with hematocrit and total plasma protein values (p < 0.05 and p < 0.001, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Cellulose↗
PubMed1995

Selenium in uremia.

The importance of selenium as an essential trace element for man has been increasingly recognized during the last several years. Selenium deficiency has been associated with cases of congestive cardiomyopathy, skeletal myopathy, anemia, enhanced cancer risk, elevated incidence of cardiovascular disease, immune system alterations, hair and nail changes, and abnormalities in thyroid hormone metabolism. These symptoms are frequently present in chronic uremic patients. Nevertheless, the prevalence and significance of selenium deficiency in the uremic syndrome is still not clearly defined. This article reviews the selenium status in chronic uremic patients, the supposed pathogenetic mechanisms of selenium disturbance in uremia, and the possible role of selenium deficiency on some uremic abnormalities.

Chronic Disease↗
PubMed1995

Effects of selenium supplementation on immune parameters in chronic uraemic patients on haemodialysis.

BACKGROUND: The involvement of selenium (Se) in immune response has been increasingly recognized, cell-mediated immunity being principally affected by Se deficiency. Blood Se levels in chronic uraemic patients are frequently lower than in controls, and in these patients cellular immunity in generally impaired. METHODS: The present study was designed to assess the effects of Se supplementation over 6 consecutive months on immune parameters in haemodialysis (HD) patients from Rostock (Germany) and Chieti (Italy). In both cities, five patients were supplemented with Se (500 micrograms thrice weekly for 3 months, then 200 micrograms thrice weekly for the next 3 months), whereas another five patients received placebo. All Se determinations were performed in a single laboratory. RESULTS: In both cities, basic plasma Se levels were significantly lower in patients than in their corresponding normal controls. After beginning Se supplementation, plasma Se concentration promptly normalized and levelled off in the normal range throughout the study. Se administration was well tolerated by all patients, and no side-effects attributable to Se toxicity were observed. Although no major change in immunocompetent cells (white blood count, total lymphocyte count, lymphocyte subpopulations) was observed during Se therapy, an improvement in T-cell response to phytohaemoagglutinin (as evaluated in Rostock patients) and a significant progressive increase in delayed-type hypersensitivity (as evaluated in Chieti patients) was observed in supplemented patients. After 6 months of Se therapy, the increase in delayed-type hypersensitivity of supplemented patients proved to be significantly higher when compared to both presupplementation values and to the results found in non-supplemented patients. Three months after suspension of Se supplementation, plasma Se levels and delayed hypersensitivity significantly decreased in Chieti patients, with both parameters returning similar to presupplementation values. CONCLUSIONS: In accordance with previous studies done in non-uraemic subjects, our investigation demonstrates for the first time the immunostimulatory properties of Se in HD patients. Though several problems on Se metabolism in uraemia remain unresolved, in our opinion moderate and safe Se supplementation can be beneficial in chronic uraemic patients.

Adjuvants, Immunologic↗