Didodecyldimethylammonium Bromide Role in Anchoring Gold Nanoparticles onto Liposome Surface for Triggering the Drug Release.

Liposomes with their capacity to anchor gold nanoparticles (AuNPs) onto their surface are used in the treatment of several pathologies such as cancer. The objective of this work was the optimization of the vesicle composition by using cationic agents in order to reinforce the anchoring process of AuNPs, and for the study of the influence of local temperature and vesicle size on drug release. A Plackett-Burman design was conducted to determine the optimal composition for the anchoring of AuNPs. A comprehensive study of the influence of lipid bilayer composition on the surface charge, size, and polydispersity index (PdI) of liposomes was carried out. Afterwards, in vitro release studies by dialysis were performed and several release parameters were evaluated as a function of temperature. Cholesterol was fixed as the rigid agent and Didodecyldimethylammonium bromide (DDAB) was selected as the cationic lipid into the liposome bilayer. Photomicrographs revealed that DDAB facilitated the anchoring of AuNPs onto the liposomal surface. The anchoring of AuNPs also enhanced the amount and rate of calcein released, especially in extruded samples, at several incubating temperatures. In addition, it was observed that both the anchoring of AuNPs and the calcein release were improved by increasing the surface of the vesicles. The contributions of liposome composition (DDAB inclusion, incubation temperature, anchoring of AuNPs) and size and surface availability of the vesicles on calcein release could be used to design improved lipid nanostructures for the controlled release of anticancer drugs.

Dynamic colonisation by different Pneumocystis jirovecii genotypes in cystic fibrosis patients.

Although asymptomatic carriers of Pneumocystis jirovecii with cystic fibrosis (CF) have been described previously, the molecular epidemiology of P. jirovecii in CF patients has not yet been clarified. This study identified the distribution and dynamic evolution of P. jirovecii genotypes based on the mitochondrial large-subunit (mt LSU) rRNA gene. The mt LSU rRNA genotypes of P. jirovecii isolates in 33 respiratory samples from CF patients were investigated using nested PCR and direct sequencing. Three different genotypes were detected: 36.3% genotype 1 (85C/248C); 15.1% genotype 2 (85A/248C); 42.4% genotype 3 (85T/248C); and 6% mixed genotypes. Patients studied during a 1-year follow-up period showed a continuous colonisation/clearance cycle involving P. jirovecii and an accumulative tendency to be colonised with genotype 3.

[Multidetector row CT in assessment of coronary artery calcification on hemodialisis]. / Valoración de las calcificaciones coronarias.

Vascular calcification is a strong predictor of cardiovascular and all-cause mortality. Coronary artery calcification is more frequent, more extensive and progresses more rapidly in CKD than in general population. They are also considered a marker of coronary heart disease, with high prevalence and functional significance. It suggests that detection and surveillance may be worthwhile in general clinical practice. New non-invasive image techniques, like Multi-detector row CT, a type of spiral scanner, assess density and volume of calcification at multiple sites and allow quantitative scoring of vascular calcification using calcium scores analogous to those from electron-beam CT. We have assessed and quantified coronary artery calcification with 16 multidetector row CT in 44 patients on hemodialysis and their relationship with several cardiovascular risk factors. Coronary artery calcification prevalence was of 84 % with mean calcium score of 1580 +/- 2010 ( r 0-9844) with calcium score > 400 in 66% of patients. It was usually multiple, affecting more than two vessels in more than 50%. In all but one patient, left anterior descending artery was involved with higher calcium score level at right coronary artery. Advanced age, male, diabetes, smoking, more morbidity, cerebrovascular disease previous, and calcium-binders phosphate and analogous vitamin D treatment would seem to be associated with coronary artery calcification. Coronary artery calcification is very frequent and extensive, usually multiple and associated to modifiable risk factors in hemodialysis patients. Multi-detector-row CT seems an effective, suitable, readily applicable method to assess and quantify coronary artery calcification.

[Good virological response to pegylated interferon alfa monotherapy of chronic hepatitis C infection in hemodialysis patient]. / Buena respuesta a interferón npegilado en monoterapia en paciente con VHC + en hemodiálisis.

Liver disease caused by hepatitis C virus infection is associated to significant morbidity and mortality among patient with end stage renal disease on maintenance hemodialysis (HD). Therapy in these patients consists of Interferon, preferably pegylated Interferon (pIFN), thus Ribavirin (RBV) is not recommended for patients with impaired renal function, outside its use in controlled trials. We report a case of 35 years young woman on HD treatment, renal transplantation candidate with chronic hepatitis C virus infection, HCV RNA positive (by PCR), genotype 3a, moderate viral load, light increase of aminotransferases. Pegylated Interferon alfa-2a (135 mcg/weekly/SC) was initiated. She achieved HVC RNA negative within 12 weeks, following with pINF as monotherapy to complete 24 weeks (6 months). Sustained virologic response persisted to 24 and 48 weeks. Most important side effects were light detriment of anemia, moderate neutropenia and thombocytopenia, transitory elevation of transaminases and "flu-like" syndrome. Adverse events were well tolerated with total compliance with pIFN dose, no requiring reduce or stop the treatment. These findings confirm that hemodialysis patients with chronic hepatitis C respond well to pegylated IFN monotherapy and a long-term sustained virologic response is achieved, appears to be better tolerated with less side effects, so combination therapy with pINF plus ribavirin is not necessary in all cases.

Prevalence of colonisation and genotypic characterisation of Pneumocystis jirovecii among cystic fibrosis patients in Spain.

Pneumocystis jirovecii colonisation may occur among cystic fibrosis (CF) patients because of their underlying pulmonary disease. A wide epidemiological analysis was performed among CF patients from Spain to assess the prevalence of P. jirovecii colonisation and the distribution of different genotypes. P. jirovecii was identified by nested PCR targeting the mitochondrial large-subunit rRNA gene from sputum samples or oropharyngeal washes. The genotype was determined by direct sequencing. The prevalence of P. jirovecii colonisation among 88 consecutive CF patients was 21.5%. The polymorphisms identified were 85C/248C (45.4%), 85T/248C (27.2%) and 85A/248C (18.1%); in one case, a mix of genotypes was found. Colonisation was more frequent in subjects aged < 18 years (25.5% vs. 15.1%). Among the patients studied, 20.8% received treatment with azithromycin; all of these patients were colonised with P. jirovecii, but none developed Pneumocystis pneumonia (PcP) during a 1-year follow-up period. Concordance in the colonisation status of siblings suggested a common source of infection or person-to-person transmission.

Increased response to subcutaneous erythropoietin on type I diabetic patients on CAPD: is there a synergistic effect with insulin?

OBJECTIVE: To evaluate the effect of subcutaneous erythropoietin (SC EPO) on the treatment of anemia in diabetic and nondiabetic continuous ambulatory peritoneal dialysis (CAPD) patients. DESIGN: A resistance index was designed for measuring the relative EPO response, dividing EPO dose (U/kg/week) by the hemoglobin (Hb) increment with respect to the basal level. PATIENTS: Eleven nonselected type I diabetic patients using subcutaneous insulin compared with 16 nondiabetic controls, all on CAPD therapy. RESULTS: The two groups showed similar mean baseline hemoglobin levels (7.4 D-I and 7.7 non-D, g/dL). There was a statistically significant lower resistance index for diabetics (13.8 +/- 9.7 U/kg/g Hb increment) compared to nondiabetic (55.8 +/- 128, p < 0.001). Multivariate analysis confirmed an independent association between diabetes and resistance index. The response to EPO was slightly better among those diabetic patients with lower levels of serum parathyroid hormone (iPTH) (PTH-resistance index, correlation coefficient, r = 0.7, p < 0.05). No other differences, apart from the use of subcutaneous insulin, were found between diabetics and controls. Although diabetic patients had an increased response to EPO, they had no more frequent side effects than nondiabetics. CONCLUSIONS: According to our results, we suggest that factors related to insulin-dependent diabetes seem to be involved in a favorable response to SC EPO. Hyperinsulinemia derived from subcutaneous use of insulin might act as a comitogen with the induced increments of serum erythropoietin.

Moncrief's technique for peritoneal catheter placement: experience of a CAPD unit.

A decrease in the peritonitis rate and the incidence of catheter exit-site/tunnel (E/T) infection are the most important factors affecting the permanent peritoneal catheter in continuous ambulatory peritoneal dialysis (CAPD) patients. Moncrief et al. have introduced a novel methodology (two phases) for peritoneal catheter placement (7.8). The most relevant characteristic is that the external portion remains buried on the subcutaneous tissue (sterile environment) during the healing process. After four to six weeks, the catheter is brought out through a small incision (0.5 cm) distal 2 cm from the subcutaneous cuff, and peritoneal dialysis may be initiated. The data available, presented by Moncrief et al., show a lower incidence of peritonitis rate and E/T infection with this implantation technique, when compared with a classic technique. The aim of this study is to learn if the placement of a peritoneal catheter with Moncrief's methodology decreases the incidence of complications related to peritoneal catheters. We treated 29 patients (group C) with the conventional procedure and 25 patients (group M) with the Moncrief technique. Follow-up was similar for both groups (C = 12.2 +/- 7.9 months vs M = 11.1 +/- 6.1 months, NS). The time buried was 3.23 +/- 0.9 weeks (2-5). Eleven patients completed four weeks with the catheter buried subcutaneously (group M-4). The incidence of E/T infection was similar for groups C and M, and lower in group M-4 (p < 0.05). The number of catheters free of infection was less in group C (31%) than in group M (46%) and M-4 (67%) (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

CAPD for treatment of ESRD patients with ascites secondary to liver cirrhosis.

The treatment of cirrhotic patients with ascites and end-stage renal disease (ESRD) is complex. Continuous ambulatory peritoneal dialysis (CAPD), as a continuous therapy, represents an alternative to hemodialysis-associated hemodynamic intolerance. We report our experience with 5 cirrhotic patients with ascites who were treated by CAPD. Three had been transferred from hemodialysis (HD) for intolerance. The hemodynamic tolerance was excellent in all patients, and solute and water peritoneal transport were increased over the normal range in all cases. Morbidity was principally related to liver disease. Peritoneal protein losses, initially high, decreased over time. Serum albumin was within the low normal range. The incidence of peritonitis was higher than usual in these patients; episodes caused by gram-negative bacteria, streptococci and listeria, were predominant. The cause of death was not CAPD-related. In our experience, CAPD should be the treatment of choice for cirrhotic patients with ascites who require dialysis.

Peritoneal resting is beneficial in peritoneal hyperpermeability and ultrafiltration failure.

Ultrafiltration failure (UFF) is one of the most frequent causes of continuous ambulatory peritoneal dialysis (CAPD) dropout and is a common consequence of peritoneal hyperpermeability secondary to inappropriate regeneration of mesothelial cells. In this paper we present the results of 25 peritoneal resting periods of 4 weeks in 16 patients who showed UFF. The mean duration of CAPD was 44 +/- 22 months. All patients had been free of peritonitis for at least 3 months when included in the peritoneal resting trial. UFF was always defined as a long-lasting decrease of UF capacity such that dry weight could no longer be achieved by CAPD. The former incidence of peritonitis was 3.9 +/- 2.3 episodes. Results compared to the preresting data: urea MTC (mass transfer coefficient) decreased from 24.9 +/- 6.8 to 21.0 +/- 6.1 (p < 0.05), creatinine MTC from 16.5 +/- 6.0 to 13.8 +/- 4.0 (p < 0.05), and UF increased from 493.8 +/- 278.0 to 881.3 +/- 388.1 (p < 0.001). The response in terms of UF in patients with low permeability ultrafiltration (creat MTC less than 13) was heterogeneous and lower than in patients with criteria of hyperpermeability (greater than 13): 720 +/- 396 to 1150 +/- 533 (NS) versus 491 +/- 310 to 808 +/- 205, respectively. Simultaneously, creatinine MTC did not change in the former group (10.2), while hyperpermeability patients showed a remarkable decrease (19 +/- 5 to 15 +/- 2, p < 0.05). In conclusion, peritoneal resting is a useful tool in the management of ultrafiltration failure in CAPD patients, primarily in those with peritoneal hyperpermeability.

Circulating burst-forming unit-erythroid (BFU-E) colonies as an early marker to measure the recombinant human erythropoietin response in peritoneal dialysis patients.

To evaluate circulating burst-forming unit-erythroid (BFU-E) cells after erythropoietin (EPO) treatment, 7 female continuous ambulatory peritoneal dialysis patients were studied [baseline hemoglobin (HB): 7-10.5 g/dL)]. EPO (4000 U subcutaneously) was administered twice weekly for two months. The control group consisted of 7 healthy women with similar demographic characteristics. Mononuclear cells (MC) (5 x 10(5)) were added to 1 mL of culture medium, supplemented with 30% fetal bovine serum, 2 U/mL of EPO, 1% bovine serum albumin, and 0.3% agar. To enumerate colonies derived from each circulating BFU-E, plates were examined by inverse light microscopy, identifying BFU-E as large aggregates with more than 100 hemoglobinized cells (HC). A remarkable individual response was observed, with Hb values ranging 8.4-13.6 g/dL at week 4 and 8.8-16.5 g/dL at week 8. Baseline levels of BFU-E in patients ranged 0-100/5 x 10(5) MC (0-358 mL of whole blood), and in controls they ranged 6-24/5 x 10(5) MC (29.6-101.3/mL) (NS). Hemoglobin levels after four and eight weeks of EPO showed a significant relationship with circulating BFU-E at baseline (r = -0.873, r = -0.928, respectively). The increment in Hb after eight weeks showed a significant relationship with baseline BFU-E (r = 0.812). Hemoglobin levels at the fourth to eighth week, and the increment in Hb after eight weeks, showed a significant, direct relationship with the increments in circulating BFU-E registered after one to two weeks of treatment. We conclude that, after the first week of EPO treatment, its effect on hemoglobin may be predieted by the increment in circulating BFU-E. Thus; a new tool to measure the earliest EPO effects has become available.

[Utility of intra-access pressure]. / La utilidad de la presión intra-acceso.

Monitoring of vascular access is essential for clinical evaluation on hemodialysis patients, detects early disfunction of access, allows adequate dialysis and decreases the morbidity associated. Although is demonstrated that intra-access pressure (IAP) is a good method of screening to evaluate arterial-venous (AV) fistulas, its utility is uncommon because its measurement requires a complex system. We would like to validate the utility of IAP monitoring using a simplified measure of IAP and its relation with other methods of screening in detecting stenoses prior to thromboses of AV grafts. We studied 24 AV grafts of 24 patients during 18 months we measured arterial pressure, mean arterial pressure (MAP), dynamic venous pressure, IAP, Kt/v, URR, recirculation index (RI), access flow and color Doppler flow, dividing the patients in two groups, with stenoses or not, if IAP/MAP > 0.5 and stenoses > 0.50 by Doppler we performed arteriography and percutaneous transluminal angioplasty with stent if stenoses exits. The values of IAP, MAP, RI were higher significantly in the stenoses group with increase of vascular access in grafts were dilation by angioplasty was made. All stenoses detected with IAP were confirmed by Doppler and arteriography but one. We conclude that IAP is an early, useful, easy, effective method in detecting stenoses of AV grafts prior to thrombosis.

[The metabolic control of insulin-dependent diabetes mellitus and diabetic nephropathy]. / Control metabólico de la diabetes mellitus insulinodependiente y nefropatía diabética.

Long-term complications of Insulin Dependent Diabetes Mellitus (IDDM) have been associated with several risk factors, particularly the degree of metabolic control and evolution time of the disease. A study was conducted with 219 randomly selected patients with IDDM at our clinic; evolutive, clinical and analytical parameters were assessed and conventional or multiple insulin therapy was evaluated. The classification of glycated hemoglobin (Hb A1c) in quartiles demonstrated a relatively higher incidence of diabetic retinopathy and nephropathy in the upper quartiles versus the lower quartile (p < 0.05). Likewise, patients with multiple insulin therapy had lower retinopathy (24.5% vs. 50.6, p < 0.001) and nephropathy rates (12.9% vs. 26.6%, p < 0.05) compared with those following a conventional insulin therapy. The multivariate analysis showed a statistically significant regression model (p < 0.001) for microalbuminuria level in patients with no established nephropathy; in these patients, the evolution time of IDDM and their Hb A1c level showed a positive independent association, and the use of multiple insulin therapy was a protective factor. The regression analysis of microalbuminuria levels compared with glycated hemoglobin in patients with no established nephropathy showed a value for Hb A1c of 9% as a break-point; from this point upwards microalbuminuria levels increased more markedly. The multivariate analysis here presented can help identify the presence of microalbuminuria in the pathological range in patients with IDDM followed at a hospital clinic from feasible clinical variables (evolution time, glycated hemoglobin level, program of insulin therapy used) establishing a metabolic objective which helps prevent the development of this complication.

Clinical significance of exit-site infections due to Xanthomonas in CAPD patients: a comparison with Pseudomonas infection.

We have assessed the clinical significance of exit-site infections secondary to Xanthomonas maltophilia in continuous ambulatory peritoneal dialysis (CAPD) patients, and compared them with episodes due to Pseudomonas. The study was a retrospective survey of all episodes of Xanthomonas and Pseudomonas-related exit-site infections (ESI) in all patients treated in our unit between 1984 and 1992. Thirteen episodes of Xanthomonas-related ESI were observed in eight patients and 17 episodes of Pseudomonas-related ESI were seen in 15 patients. Xanthomonas-related ESI was frequently associated with other microorganisms, while Pseudomonas-related ESI was not (66% versus 5%, P < 0.02). Only one episode of Xanthomonas-related ESI resulted in peritonitis and subsequent catheter removal, after 15 months of resistant colonization. Another case was considered to be chronic and indolent, as the Xanthomonas-related ESI continued after 23 months of local treatment. The other 11 episodes were resolved either without treatment or with an antibiotic cream after 7-120 days. However, all but two episodes of Pseudomonas-related ESI required intravenous antibiotics (usually ceftazidime); seven patients developed peritonitis, and 11 required surgical catheter manipulation (five external cuff extrusion, and six catheter removal) (1/13 Xanthomonas-related versus 11/17 Pseudomonas-related ESI, P < 0.03). Most Xanthomonas-related ESI do not lead to peritonitis, and constitute a mild condition, easily treatable without parenteral antibiotics or catheter replacement. The appearance of other associated organisms and the favourable evolution with local treatment suggest a saprophytic behaviour for Xanthomonas in our CAPD patients. On the contrary, Pseudomonas-related ESI is usually severe, requires parenteral antibiotics, frequently leads to peritonitis, and requires catheter replacement.