Complex rhamnolipid mixture characterization and its influence on DPPC bilayer organization.

Rhamnolipids (RL) are one of the most important classes of biosurfactants produced by microorganisms using a wide range of carbon sources, from a simple carbon source like glucose to complex wastes such as the used cooking oils used in this work. The objective of this work was to learn about the rhamnolipid-phospholipid dipalmitoyl phosphatidyl choline (DPPC) molecular interactions through the behaviour observed in the neat products and four RL/DPPC mixtures. Size and z-potential were used to characterize the size and the charge of the vesicles, and small angle X-ray scattering (SAXS) was used to measure the vesicle bilayer characteristics, and the release of carboxyfluorescein to study the bilayer disrupting effect promoted by rhamnolipids. The results show that rhamnolipids are disposed in ordered bilayers with long repeating distances, which are stabilized by the charging of the bilayer and also by a strong fluidity of the bilayers. The ability of rhamnolipids to increase the fluidity of DPPC bilayers may be related with the strong haemolytic power of these molecules.

Cerebrospinal fluid synaptic proteins as useful biomarkers in tyrosine hydroxylase deficiency.

Tyrosine hydroxylase (TH) deficiency is an inborn error of dopamine biosynthesis and a cause of early parkinsonism. Two clinical phenotypes have been described. Type "B": early onset severe encephalopathy; type "A": later onset, less severe and better response to L-dopa. We aimed to study the expression of several key dopaminergic and gabaergic synaptic proteins in the cerebrospinal fluid (CSF) of a series of patients with TH deficiency and their possible relation with the clinical phenotype and response to L-DOPA. Dopamine transporter (DAT), D2-receptor and vesicular monoamine transporter (VMAT2) were measured in the CSF of 10 subjects with TH deficiency by Western blot analysis. In 3 patients, data of pre- and post-treatment with L-DOPA were available, and in one of them, GABA vesicular transporter was determined. Results were compared to an age-matched control population. The concentration of D2-receptors in CSF was significantly higher in patients with TH deficiency than in controls. Similarly, DAT and vesicular monoamine transporter type 2 were up-regulated. Studies performed before L-DOPA, and on L-DOPA therapy showed a paradoxical response with D2 receptor expression increase as L-Dopa doses and homovanillic concentration gradually raised in a B phenotype patient. The opposite results were found in two patients with A phenotype. However, this is a very small sample, and further studies are needed to conclude robust differences between phenotypes. Synaptic proteins are detectable in the CSF and their quantification can be useful for understanding the pathophysiology of neurotransmitter defects and potentially to adjust and personalize treatments in the future.

Niosomes based on synthetic cationic lipids for gene delivery: the influence of polar head-groups on the transfection efficiency in HEK-293, ARPE-19 and MSC-D1 cells.

We designed niosomes based on three lipids that differed only in the polar-head group to analyze their influence on the transfection efficiency. These lipids were characterized by small-angle X-ray scattering before being incorporated into the niosomes which were characterized in terms of pKa, size, zeta potential, morphology and physical stability. Nioplexes were obtained upon the addition of a plasmid. Different ratios (w/w) were selected to analyze the influence of this parameter on size, charge and the ability to condense, release and protect the DNA. In vitro transfection experiments were performed in HEK-293, ARPE-19 and MSC-D1 cells. Our results show that the chemical composition of the cationic head-group clearly affects the physicochemical parameters of the niosomes and especially the transfection efficiency. Only niosomes based on cationic lipids with a dimethyl amino head group (lipid 3) showed a transfection capacity when compared with their counterparts amino (lipid 1) and tripeptide head-groups (lipid 2). Regarding cell viability, we clearly observed that nioplexes based on the cationic lipid 3 had a more deleterious effect than their counterparts, especially in ARPE-19 cells at 20/1 and 30/1 ratios. Similar studies could be extended to other series of cationic lipids in order to progress in the research on safe and efficient non-viral vectors for gene delivery purposes.

PLP1 gene analysis in 88 patients with leukodystrophy.

Pelizaeus-Merzbacher disease (PMD) is caused in most cases by either duplications or point mutations in the PLP1 gene. This disease, a dysmyelinating disorder affecting mainly the central nervous system, has a wide clinical spectrum and its causing mutations act through different molecular mechanisms. Eighty-eight male patients with leukodystrophy were studied. PLP1 gene analysis was performed by the Multiplex Ligation-dependent Probe Amplification technique and DNA sequencing, and, in duplicated cases of PLP1, gene dosage was completed by using array-CGH. We have identified 21 patients with mutations in the PLP1 gene, including duplications, short and large deletions and several point mutations in our cohort. A customized array-CGH at the Xq22.2 area identified several complex rearrangements within the PLP1 gene region. Mutations found in the PLP1 gene are the cause of PMD in around 20% of the patients in this series.

Structure and phase equilibria of the soybean lecithin/PEG 40 monostearate/water system.

PEG stearates are extensively used as emulsifiers in many lipid-based formulations. However, the scheme of the principles of the lipid-surfactant polymer interactions are still poorly understood and need more studies. A new phase diagram of a lecithin/PEG 40 monostearate/water system at 30 °C is reported. First, we have characterized the binary PEG 40 monostearate/water system by the determination of the critical micelle concentration value and the viscous properties. Then, the ternary phase behavior and the influence of phase structure on their macroscopic properties are studied by a combination of different techniques, namely, optical microscopy, small-angle X-ray scattering, differential scanning calorimetry, and rheology. The phase behavior is complex, and some samples evolve even at long times. The single monophasic regions correspond to micellar, swollen lamellar, and lamellar gel phases. The existence of extended areas of phase coexistence (hexagonal, cubic, and lamellar liquid crystalline phases) may be a consequence of the low miscibility of S40P in the lecithin bilayer as well as of the segregation of the phospholipid polydisperse hydrophobic chains. The presence of the PEG 40 monostearate has less effect in the transformation to the cubic phase for lecithin than that found in other systems with simple glycerol-based lipids.

Tocilizumab treatment for nephrotic syndrome due to amyloidosis in Behcet's disease.

Renal involvement is an unusual but significant Behcet´s disease (BD) complication and AA amyloidosis appears to be the most common etiology. IL-6 is a pro-inflammatory cytokine with an important role in AA amyloidosis development. Tocilizumab (TCZ) is a humanized anti-IL-6 receptor antibody that has emerged as an effective and specific treatment in AA amyloidosis secondary to chronic inflammatory disorders. We report on a patient diagnosed with BD who developed nephrotic syndrome caused by renal AA amyloidosis with an excellent response to TCZ therapy.

Nephrotic syndrome and AA amyloidosis revealing adult-onset cryopyrin-associated periodic syndrome.

Cryopyrin-associated periodic syndrome (CAPS) is due to gain-of-function mutations in the cryopyrin gene, which determines an overactive inflammatory response. AA amyloidosis is a complication of this syndrome. A 53-year-old man was referred to us because of lower limb edema. Past history: at the age of 20, he complained of arthralgia/arthritis and bilateral hypoacusis. At the age of 35, he presented posterior uveitis, several episodes of conjunctivitis, and progressive loss of visual acuity. Laboratory tests disclosed nephrotic syndrome, and renal biopsy showed AA amyloidosis. He was given anakinra with improvement of arthritis. A genetic study revealed the p.D303N mutation in the cryopyrin gene, and he was diagnosed as having AA amyloidosis due to CAPS. Twenty-one months after starting anakinra, the arthritis has disappeared, although nephrotic-range proteinuria persisted. It is important to be aware of cryopyrin-associated periodic syndrome because it can cause irreversible complications, and there is effective therapy.

Mitochondrial neurogastrointestinal encephalomyopathy: Clinical and biochemical impact of allogeneic stem cell transplantation in a Greek patient with one novel TYMP mutation.

We describe the case of a Greek female patient with the Classic form of the ultra- rare and fatal autosomal recessive disorder Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) and the impact of allogeneic hematopoietic stem cell transplantation on the biochemical and clinical aspects of the disease. The patient presented at the age of 15 years with severe gastrointestinal symptoms, cachexia, peripheral neuropathy and diffuse leukoencephalopathy. The diagnosis of MNGIE disease was established by the increased levels of thymidine and deoxyuridine in plasma and the complete deficiency of thymidine phosphorylase activity. The novel c.[978dup] (p.Ala327Argfs*?) variant and the previously described variant c.[417 + 1G > A] were identified in TYMP. The donor for the allogeneic hematopoietic stem cell transplantation was her fully compatible sister, a carrier of the disease. The patient had a completely uneventful post- transplant period and satisfactory PB chimerism levels. A marked and rapid decrease in thymidine and deoxyuridine plasma levels and an increase of the thymidine phosphorylase activity to the levels measured in her donor sister was observed and is still present sixteen months post-transplant. Disease symptoms stabilized and some improvement was also observed both in her neurological and gastrointestinal symptoms. Follow up studies will be essential for determining the long term impact of allogeneic hematopoietic stem cell transplantation in our patient.

Distal Transradial Access for Diagnostic Cerebral Angiography and Neurointervention: Systematic Review and Meta-analysis.

BACKGROUND: Radial artery access for cerebral angiography is traditionally performed in the wrist. Distal transradial access in the anatomic snuffbox is an alternative with several advantages. PURPOSE: Our aim was to review the safety and efficacy of distal transradial access for diagnostic cerebral angiography and neurointerventions. DATA SOURCES: We performed a comprehensive search of the literature using PubMed, Scopus, and EMBASE. STUDY SELECTION: The study included all case series of at least 10 patients describing outcomes associated with distal transradial access for diagnostic cerebral angiography or a neurointervention. DATA ANALYSIS: Random-effects models were used to obtain pooled rates of procedural success and complications. DATA SYNTHESIS: A total of 7 studies comprising 348 (75.8%) diagnostic cerebral angiograms and 111 (24.2%) interventions met the inclusion criteria. The pooled success rate was 95% (95% CI, 91%-98%; I2 = 74.33). The pooled minor complication rate was 2% (95% CI, 1%-4%; I2 = 0. No major complications were reported. For diagnostic procedures, the combined mean fluoroscopy time was 13.53 [SD, 8.82] minutes and the mean contrast dose was 74.9 [SD, 35.6] mL. LIMITATIONS: A small number of studies met the inclusion criteria, all of them were retrospective, and none compared outcomes with proximal transradial or femoral access. CONCLUSIONS: Early experience with distal transradial access suggests that it is a safe and effective alternative to proximal radial and femoral access for performing diagnostic cerebral angiography and interventions. Additional studies are needed to establish its efficacy and compare it with other access sites.

Fluid-structure interaction simulations outperform computational fluid dynamics in the description of thoracic aorta haemodynamics and in the differentiation of progressive dilation in Marfan syndrome patients.

Abnormal fluid dynamics at the ascending aorta may be at the origin of aortic aneurysms. This study was aimed at comparing the performance of computational fluid dynamics (CFD) and fluid-structure interaction (FSI) simulations against four-dimensional (4D) flow magnetic resonance imaging (MRI) data; and to assess the capacity of advanced fluid dynamics markers to stratify aneurysm progression risk. Eight Marfan syndrome (MFS) patients, four with stable and four with dilating aneurysms of the proximal aorta, and four healthy controls were studied. FSI and CFD simulations were performed with MRI-derived geometry, inlet velocity field and Young's modulus. Flow displacement, jet angle and maximum velocity evaluated from FSI and CFD simulations were compared to 4D flow MRI data. A dimensionless parameter, the shear stress ratio (SSR), was evaluated from FSI and CFD simulations and assessed as potential correlate of aneurysm progression. FSI simulations successfully matched MRI data regarding descending to ascending aorta flow rates (R 2 = 0.92) and pulse wave velocity (R 2 = 0.99). Compared to CFD, FSI simulations showed significantly lower percentage errors in ascending and descending aorta in flow displacement (-46% ascending, -41% descending), jet angle (-28% ascending, -50% descending) and maximum velocity (-37% ascending, -34% descending) with respect to 4D flow MRI. FSI- but not CFD-derived SSR differentiated between stable and dilating MFS patients. Fluid dynamic simulations of the thoracic aorta require fluid-solid interaction to properly reproduce complex haemodynamics. FSI- but not CFD-derived SSR could help stratifying MFS patients.

The phenotypic spectrum of paediatric neurotransmitter diseases and infantile parkinsonism.

Paediatric neurotransmitter diseases are a group of inherited disorders attributable to a disturbance of neurotransmitter metabolism. The monoamines, catecholamines and serotonin, also called biogenic amines, are neurotransmitters with multiple roles including psychomotor function, hormone secretion, cardiovascular, respiratory and gastrointestinal control, sleep mechanisms, body temperature and pain. Given the multiple functions of monoamines, disorders of their metabolism comprise a wide spectrum of manifestations, with motor dysfunction being the most prominent clinical feature. The severity of the clinical manifestations ranges from mild to severe. Patients with severe and intermediate phenotypes may present with infantile parkinsonism that differs in a number of aspects from the parkinsonism in nigrostriatal degeneration. Analysis of monoamine metabolites and pterins in spinal fluid assists in the diagnosis of these disorders. Treatment options include tetrahydrobiopterin supplementation, L: -dopa, 5-hydroxytryptophan, and medications that potentiate monoamine transmission. Response to treatment is variable.

[Determination of brain natriuretic peptide in patients undergoing different haemodiafiltration techniques]. / Determinación del péptido natriurético cerebral en pacientes sometidos a diferentes técnicas de hemodiafiltración.

UNLABELLED: IB-type natriuretic peptide is a cardíac neurohormone secreted by the cardíac ventricules in response to ventricular dilatation so plasma BNP level correlate with left ventricular mass and dysfunction. Dialysis patients have much greater levels of BNP due to the volume overload and because of reduced renal clearance. The aim of this study was to mesure and compare the BNP levels in three groups of patients who received different hemodiafiltration techniques: Daily online hemodiafiltration (HDFOLd), on-line hemodiafiltration (HDFOL) and low convective volume hemodiafiltration (HDF). Fifteen patients were included, five in each group. Pre and postdialysis BNP leves were measured during 8 weeks. The measure was done at the beginning of the week (long period), and at the end (short period), in order to study if there were significative differences between techniques and periods. We found significative differences between predialysis BNP levels in the short period (BNPpreC) and the long period (BNPpre-L). We also found significative differences with the posdialysis BNP in both periods; BNPpre- L vs. BNPpos-L (1069+/-1031 vs. 612 +/- 540). After comparing the three techniques the study showed significative differences between BNPpreC in HDF and HDFOL compared with HDFOld. And also after dialysis between BNPpos-C in HDFOLd compared with the other techniques. CONCLUSION: Although previous papers have shown that BNP levels have limited potential for assessment of hydration in hemodialysis patients, in this study our data demonstrate that after dialysis BNP levels decline in a significative way in the long and short period and we have found that patients on daily hemodialysis show lower BNP levels, and maybe this could be explained because daily on-line haemodiafiltration patients had lower weight rise between dialysis sessions and also better haemodynamic tolerance.

Aggregation properties of diacyl lysine surfactant compounds: hydrophobic chain length and counterion effect.

In this paper, we report on the study of aqueous solution and aggregation properties of diacyl Lysine surfactant salts with several surfactant counterions at a fixed hydrophobic chain length. They present a critical micellar concentration nearly independent of the counterion. The area per surfactant molecule is around 1.3 nm (2) also independent of the counterion. We have also studied the dry state crystallization of these surfactant salts. We show that small counterion systems tend to form bicontinuous cubic structures and that the increase in counterion size tends to form lamellar structures. We have compared this behavior with the dry state crystallization of the diacyl Lysine surfactants as a function of hydrophobic chain length. For long hydrophobic chains, the crystal structure is lamellar, while for intermediate, length is cubic. Among the structures studied, the one with the shortest chain length crystallizes in a hexagonal inverse phase.

Lamellar rearrangement of internal lipids from human hair.

The internal lipids were extracted from untreated hair without surface lipids. Liposomes were formed with the internal lipids at different hydration levels to determine the organization of these lipids and the influence of the water content on the lamellar structure of the hair fibres by X-ray Scattering (SAXS). Two structures of hair lipids were observed at 4.5 and approximately 9.0 nm with a different behaviour as a function of water content: the largest bilayer being the one that showed a capacity to retain water inside its structure. SAXS was also applied directly to three samples: a packed swatch of hair fibres at 60% RH, fibres soaked in water and delipidized fibres. Only the lamella at 9.0 nm was slightly affected by water content. Moreover, there was a small diminution in intensity probably due to a high permeability of wet fibres which could give rise to a disorder of the lipid structure. These two lamellar rearrangements are probably made up of lipids with a different and specific hydrophilic/hydrophobic balance.

[Kinetic of calcium, phosphate, magnesium and PTH variations during hemodiafiltration]. / Cinéica del calcio, fósforo, magnesio y variaciones de la parathormona (PTH) en pacientes en hemodiafiltracion.

Hemodiafiltration (HDF) is a technique resulting from coupling of diffusive and convective transport and thereby increase the elimination of small and middle molecules. However, may induce a convective loss from others substances such as calcium and magnesium. The aim of this study was to evaluate the effects of Ultrafiltration on the kinetics of calcium, phosphate, magnesium and parathyroid hormone. A total of thirteen patients (7 males and 6 females) on hemodialysis, were studied. Each patient was randomly dialyzed with the same dialysate calcium concentration and three different ultrafiltration rate. Schedule A: High flux hemodialysis, schedule B: HDF with 10% of weight body and schedule C: HDF with 20% of weight body. The others parameters were kept identical. Total Ultrafiltration was 2,6+/-0,9 L (9,78+/-3,78 ml/min) in A, 9,3+/-1,7 L (34,54+/-6,22 ml/min) in B and 16,3+/-3,3 L (60,94+/-12,63 ml/min) in C. Replacement fluid during dialysis was 6,85+/-1,42 and 13,65+/-2,9 L. in C and C respectively. Postdialysis total,ionized calcium and magnesium were significantly lower in schedules B and C versus A. PTH levels did not differ significantly. However, PTH changes during dialysis was -36.6+/-38.6%, 6.3+/-69.8% and 32.2+/-63.2% in A, B and C, respectively (p<0.05 A vs. C). A significant inverse correlation was found between total Ultrafiltration and postdialysis levels of total calcium (r:-0.56, p<0.001), ionized calcium (r:-0.65, p<0.001) and magnesium (r:-0.47, p<0.01). No differences were observed in pre and postdialysis phosphate levels, neither mass transfer and clearance of phosphate. We concluded that high ultrafiltration flow rates and substitution fluid without divalent cations induces a negative calcium and magnesium balance. These changes may stimulate PTH secretion during HDF. This technique did not resulted in a higher clearance or phosphate removal.

[Oxidative stress analysis in patients on hemodiafiltration on-line]. / Análisis del estrés oxidativo en pacientes en hemodiafiltración en línea.

Patients with chronic renal disease have a very high mortality due to cardiovascular disease. However, the traditional risk factors are not the only one explanation. Nowadays, there are new risk factors becoming, and one of these is the oxidative stress. Besides today we know that when these patients receive haemodialysis are being exposed to an additional oxidative stress. The aim of this study was to measure and to compare the degree of oxidative stress in two groups of patients on different dialysis techniques: a) On-Line Haemodiafiltration three times / week (OL-HDF). b) Daily Om-Line haemodiafiltration ( six times / week ) ( dOL-HDF) We studied 9 patients with chronic renal disease stage 5 on hemodialysis. They all were men, with a medium age of 72,5 +/- 6 years. Five patients were on dOL-HDFand four on tOL-HDF. Glutathione (GSH) concentration of patients on dOL-HDF before dialysis was 742+/- 153 nmol/ml and post-dialysis de 878+/- 223. Blood GSSG concentration before and after dialysis was 34+/- 14 nmol/ml y 137+/- 74 nmol/ml (p< 0,03). GSSG/GSH ratio pre-dialysis was 58+/-10 and post-dialysis 169+/-65 ( p < 0,03). In OL-HDF group GSSG concentration and the ratio GSSG/GSH also increased in a significative way from 99+/-45 nmol/ml to 179+/-66 nmol/ml, and from 161+/- 99 to 337+/-143 ( p<0,05). We also found differences in pCR concentrations between both groups; 3+/-1,4 g/l in dOL-HDF and 8,75+/-5,8 g/l in HDF OL. (p< 0,05). We did not find differences between xatine-oxidase activity before and after hemodialysis and between groups. In conclusion, patient with terminal chronic renal disease on OL-HDF receive an additional load of oxidative stress, as the increase in GSSG/GSH ratio in both groups shows. However patients on dHDF-OL shows low ratios GSSG/GSH post-hemodialysis and low pCR concentrations, and maybe this could be explained because daily on line haemodiafiltration improves purification of inflammatory mediators. Clue words: Hemodialysis, oxidative stress, glutathione, gssg/gsh ratio, xantine oxidasa.

Study and formation of vesicle systems with low polydispersity index by ultrasound method.

The formation of liposomes with low polydispersity index by application of ultrasounds was investigated considering methodology specifications such as sonication time and sonication power. Phosphatidylcholine (PC) liposomes were formed by the evaporation-hydration method. The vesicles were sonicated using several sonication conditions. The liposomes were then characterized by dynamic light scattering (DLS) and freeze-fracture electron microscopy (FFEM). Correlation functions from DLS were treated by cumulants method and GENDIST to obtain the mean radius and polydispersity index. These calculations allowed to fix an optimal sonication time (3000 s) and a useful interval of ultrasound power between 39 and 91 W. DLS and FFEM results confirmed that vesicle size, lamellarity and the polydispersity index decreased with the increase of sonication power. Thus, we propose a systematic method to form liposomes in which the physical characteristics of the vesicles may be controlled as a function of sonication time and power.

[Estimation of the cost in the farmacologic treatment of chronic renal failure]. / El coste del tratamiento farmacológico en la enfermedad renal crónica.

The prevalence and incidence of end stage renal disease has increased considerably in the past years. We know that the cost of treatment of these patients is high. Limited information exists on care resource utilization for maintenance of patients before the initiation of replacement therapy. The purpose of this study is determine the cost of pharmaceutic treatment during the predialysis phase. Pharmacy cost was analyzed for 200 patients controlled on outpatient nephrology department. The mean age was 72.4 years, 59% were males, and the comorbidity distribution was: hypertension 87%, hyperlipidemia 56% and diabetes 35%. The per-patient-per-month charges were 215.45 Euro, with a continous increase from 84.64 Euro on stage 1 to 352.59 Euro on stage 5 of chronic kidney disease. Erythropoiesis stimulants were reponsible of 46.5% of these cost. The most frequent prescribed medications were antihypertensive drugs, statins and iron preparations. Patients with end stage renal disease generate significant cost during the predialysis period. The limited resources, and the growth of health care expeditures, particulary the spending for prescriptions drugs, are two of the major problems for Health Care Systems. A better knowledge of the associated costs to the treatment of these patients will help us to increase our efficiency.

New cationic vesicles prepared with double chain surfactants from arginine: Role of the hydrophobic group on the antimicrobial activity and cytotoxicity.

Cationic double chain surfactants have attracted much interest because they can give rise to cationic vesicles that can be used in biomedical applications. Using a simple and economical synthetic approach, we have synthesized four double-chain surfactants with different alkyl chain lengths (LANHCx). The critical aggregation concentration of the double chain surfactants is at least one order of magnitude lower than the CMC of their corresponding single-chain LAM and the solutions prepared with the LANHCx contain stable cationic vesicles. Encouragingly, these new arginine derivatives show very low haemolytic activity and weaker cytotoxic effects than conventional dialkyl dimethyl ammonium surfactants. In addition, the surfactant with the shortest alkyl chain exhibits good antimicrobial activity against Gram-positive bacteria. The results show that a rational design applied to cationic double chain surfactants might serve as a promising strategy for the development of safe cationic vesicular systems.