Biomedical subjects

Emanuela Buoncristiani

Publications and source records attributed to Emanuela Buoncristiani.

6 recordsLinked to original sources

PubMed2007

Antisepsis.

All dialysis treatments include a certain risk of infection because of the decreased immune defenses of the patients and because of dialytic techniques that increase the potential of microbial contamination. Peritoneal dialysis, and in particular continuous ambulatory peritoneal dialysis (CAPD), has a higher risk of infections of the peritoneum, but even of the subcutaneous tunnel. These infections are caused by environmental microorganisms principally gram-positives (Staphylococcus epidermidis and Staphylococcus aureus). We tested three active ingredients, electrolytic chloroxidizer, iodine and chlorhexidine gluconate. It is evident that because of the large spectrum of activity, the good effectiveness even at the lowest concentration, coupled with good tolerability (and to the fact of not causing allergic reactions) the electrolytic chloroxidizer appears to be an ideal antiseptic in CAPD.

Anti-Infective Agents, Local↗

PubMed2007

Use of sodium hypochlorite in peritoneal dialysis: the genesis of the 'Y' set and beyond.

The 'Y' set introduced in the clinical practice in the early 80s with the aim of reducing the peritonitis rate in patients on continuous ambulatory peritoneal dialysis, successfully revolutioned the philosophy of the connection system catheter-container of dialysate, which was the main way of bacterial contamination of the peritoneal cavity. In fact, while the previous connection systems had focused the attention on the reduction of the possible contaminating acts, the 'Y' system, taking into account the fact that soon or later a failure could occur even with the most skilled and compliant patient, introduced the possibility to kill the bacteria with a disinfectant and to remove it and the killed bacteria together with the bacteria eventually still surviving, by flushing the contaminated area. This goal was achieved thanks to a 'Y' shaped connector, having a third way connected to the discharge bag/container, besides the two connected to the new bag and to the catheter. From the 'Y' set have originated all the currently used continuous ambulatory peritoneal dialysis connection systems, where the 'Y' is mounted on the bag side (double-bag systems). However in these systems the disinfectant is no longer used, due to the fear of possible untoward effects on the peritoneal membrane. The groundlessness of this position and the possible further advantages of the use of a disinfectant in combination with the 'Y' are discussed and new 'Y' systems preventing every possibility of accidental entry of disinfectant into the peritoneal cavity are presented.

Bacterial Infections↗

PubMed2005

Glycoxidation and inflammatory markers in patients on treatment with PMMA-based protein-leaking dialyzers.

BACKGROUND: High-molecular-weight solutes such as glycation and oxidation protein products are putative proinflammatory mediators found in the uremic blood. The elimination of these and other large solutes by protein-leaking dialyzers (PLD) might help to correct the inflammatory status of maintenance hemodialysis (HD) patients. METHODS: Two matched groups of 13 standard 3 times/week HD patients were treated for 6 months with PMMA-based PLD and non-protein-leaking dialyzers (NPLD), respectively. At baseline, 1, 3, and 6 months, we measured the blood levels of the inflammatory cytokines IL-1beta, TNF-alpha, IL-6, the acute-phase protein C-reactive protein (CRP), the adhesion molecules ICAM-1, VCAM-1, and selectine-E, the chemotaxis factors MCP-1, and the glycation and oxidation protein end products pentosidine, protein carbonyls, and AOPP. RESULTS: In all the patients at baseline, pre-HD levels of glycation and oxidation protein markers, and inflammatory parameters were significantly higher than in healthy control subjects (P < 0.01 or greater). After 6 months, in the group on treatment with PLD, but not in that on NPLD, there was a significant decrease (P < 0.05 or greater) of pre-HD values of total pentosidine (mainly represented by pentosidine in serum albumin; -43%), protein carbonyls (-42%), AOPP (-38%), and the inflammatory cytokines IL-1beta (-49%), IL-6 (-39%), and TNF-alpha (-20%), while IL-10 and INF-gamma increased by 67% and 37%, respectively. Proinflammatory cytokines, and particularly IL-6, showed a positive correlation with the levels of circulating pentosidine. Protidemia was not significantly modified at the end of the study in both the groups. CONCLUSION: The results in this pilot study show that the removal of large solutes by PLD can improve some indices of chronic inflammation in HD patients. Further studies are required to determine the relevance of the individual solutes removed with PLD as proinflammatory mediators in the uremic environment.

Adult↗

PubMed2005

Effect of daily hemodialysis on monocytes apoptosis.

Uremia is associated with a state of immune dysfunction with increased susceptibility to infection and malignancy possibly related to dysregulation of immune system cell apoptosis. Peritoneal dialysis can restore plasma apoptosis activity on monocytes compared to intermittent hemodialysis. Whether the continuous modality or diverse clearance mechanisms involved are responsible is unknown. Apoptosis rates correlate with phagocytic function highlighting the benefit of efficient toxin clearance. The plasma of 16 patients on daily hemodialysis (D-HD) was incubated with U937 monocytes and compared to 18 hemodialysis (HD) patients, 5 chronic renal failure (CRF) subjects and 5 healthy volunteers (controls). Apoptosis was evaluated by immunofluorescence microscopy dyes (Hoechst 33342, propidium iodide) and annexin V cytoflowmetry at 96 h. Plasma-induced U937 apoptosis (mean values) was significantly enhanced in D-HD (18.8 +/- 4.1), HD (19.67 +/- 5.5) and CRF patients (20.8 +/- 4.7) compared to controls (9.6 +/- 3.6; p < 0.05 for CRF vs. controls, HD vs. controls and D-HD vs. controls). No significant differences were observed between D-HD, HD and CRF sera on apoptosis rate, caspase-3 activity and phagocytic capacity of U937 monocytes. This study demonstrates that the plasma of various HD schedules was unable to reduce monocyte apoptosis induced by uremia.

Adult↗

PubMed2003

The effect of PMMA-based protein-leaking dialyzers on plasma homocysteine levels.

BACKGROUND: Hyperhomocysteinemia is a well-recognized independent risk factor for cardiovascular disease in end-stage renal disease (ESRD) patients. Since homocysteine (Hcy) largely binds to serum proteins (80 to 90%), in this study we investigated the possibility that polymethylmethacrylate (PMMA)-based protein-leaking dialyzers could reduce total plasma Hcy (tHcy) levels in ESRD patients. METHODS: Two matched groups of patients (N = 13) showing mild to intermediate hyperhomocysteinemia on standard hemodialysis (HD) with conventional non-protein-leaking dialyzers were included. In the control group membranes were maintained the same, while the study group was switched to protein-leaking dialyzers (BK-F series; Toray, Japan) and studied for 6 months. tHcy was measured by high performance liquid chromatography (HPLC) at baseline and after 1, 3, and 6 months. Proteins and Hcy were also measured in the spent dialysate. RESULTS: The pre-HD levels of tHcy in the control group remained close to baseline values (26.6 +/- 5.0 micromol/L), while in the study group at 1, 3, and 6 months they decreased from a baseline value (in micrormol/L) of 25.3 +/- 5.9 to 21.5 +/- 4.5, 16.9 +/- 4.0, and 17.2 +/- 4.2, respectively (P < 0.01 for values at 3 and 6 months vs. baseline). The intra-HD drop of tHcy (Delta HDHcy) slightly but progressively decreased during the 3 steps on protein-leaking dialyzers and a positive correlation was found between Delta HDHcy and pre-HD levels of tHcy. In spent dialysate samples from protein-leaking dialyzer-treated patients, the amount of protein-bound Hcy (bHcy) was approximately 10 times higher than in non-protein-leaking dialyzers, but the Delta HDHcy observed in non-protein-leaking dialyzers and protein-leaking dialyzers was comparable. Serum proteins and albumin were only slightly affected by protein-leaking dialyzers. CONCLUSION: This study demonstrates that protein-leaking dialyzers used with a pure diffusive technique significantly lower pre-HD tHcy (approximately 33% of starting levels after 3 months of treatment) in ESRD patients. A possible underlying mechanism for this effect could be the removal of large molecular weight solutes responsible for a defective metabolism of the Hcy, as the removal of bHcy with protein-leaking dialyzers seems not sufficient, per se, to explain this steady reduction of tHcy levels in pre-HD.

Aged↗

PubMed2003

Association between extracellular water, left ventricular mass and hypertension in haemodialysis patients.

BACKGROUND: Hypertension and left ventricular hypertrophy (LVH) are present in the majority of patients undergoing haemodialysis (HD). These two pathologies persist after dialysis onset, and pharmacological therapy is often required for adequate control of blood pressure (BP). Although fluid overload is a determinant of hypertension, clinical assessment of this parameter remains difficult and unsatisfactory. Bioimpedance analysis (BIA) spectroscopy and the relative determination of extracellular water (ECW%) may provide a simple and inexpensive tool for investigating fluid overload. We studied 110 patients on thrice-weekly HD to determine whether ECW body content correlates with hypertension and LVH in this patient population. METHODS: Hypertension was determined according to the WHO criteria (office BP >/= 140/90 and/or the use of antihypertensive therapy). Twenty-four hour BP monitoring and echocardiography were performed on midweek inter-HD days. Blood chemistries, dialysis dose (spKt/V) and bioimpedance were analysed on midweek HD days. RESULTS: Hypertension was present in 74.5% of patients. There were no differences for age, spKt/V, haemoglobin, serum creatinine and residual renal function between normotensive and hypertensive patients. Twenty-four hour systolic BP (SBP), 24 h diastolic BP and 24 h pulse pressure were higher in hypertensive patients, in spite of antihypertensive therapy. LVH was present in 61.8% of patients. BIA revealed that ECW% was increased in LVH+ patients (LVH+ = 47.5 +/- 7.9%, LVH- = 42.4 +/- 6.2%, P = 0.01) and in hypertensive patients compared with normotensives (46.5 +/- 7.7% vs 43 +/- 7.2%, P = 0.02). Dry body weights and inter-HD body weight increases did not differ between hypertensive and normotensive patients nor between patients with or without LVH. ECW was correlated with SBP (r = 0.35, P < 0.01) and with left ventricular mass index (LVMi(g/sqm)) (r = 0.49, P < 0.001). A stepwise multiple linear regression model revealed that LVMi(g/sqm) was significantly correlated with ECW%, SBP and male gender (r = 0.65, P < 0.001). CONCLUSIONS: LVH and hypertension are present in a majority of HD patients and they are closely correlated with one another. We found associations between fluid load, measured by BIA and expressed as ECW, and BP and LVM.

Adult↗