Biomedical subjects

M P Vinardell

Publications and source records attributed to M P Vinardell.

At least 19 recordsLinked to original sources

PubMed2006

Determination of interleukin-1alpha in human NCTC 2544 keratinocyte cells as a predictor of skin irritation from lysine-based surfactants.

Lysine derivative surfactants are a class of amino acid-based surfactants synthesized as lecithin analogues that deserve particular attention because of their low toxicity and high biocompatibility. To complete the toxicological profile of these surfactants, IL-1 alpha production (cell-associated and release to the culture medium) was determined as an in vitro method for predicting skin irritation. In addition, an MTT assay was used as a viability marker in keratinocytes NCTC 2544. Keratinocytes are a biologically relevant target for developing in vitro techniques to assess skin irritants: moreover, they are the principal source of the proinflammatory cytokine IL-1 alpha in the epidermis. Lysine derivatives proved to be less potent in stimulating IL-1 alpha synthesis and induced a lower release of this cytokine into the culture medium when compared to the anionic surfactant sodium dodecyl sulfate. Due to their low irritancy potential, lysine-based surfactants may offer promising applications in pharmaceutical and cosmetic preparations.

Cell Line↗

PubMed2006

The biological properties of lysine-derived surfactants.

We examine the effects of aquatic toxicity on Daphnia magna, the antimicrobial activity of new anionic lysine-derivative surfactants, and the influence of different-sized counterions associated with the surfactants. Surfactants with Tris and Lithium had less of a toxic effect on Daphnia, while all surfactants proved highly active against yeasts and the gram-negative bacteria Bordetella bronchiseptica. Counterion size was found to have no effect on aquatic toxicity or antimicrobial activity.

Animals↗

PubMed2006

Evaluation of eye and skin irritation of arginine-derivative surfactants using different in vitro endpoints as alternatives to the in vivo assays.

Arginine-derivative surfactants constitute a novel class of surfactants, which can be regarded as an alternative to conventional surfactants. Prior to human exposure, it is necessary to assess their irritation potential. The classical in vivo evaluation of the irritancy potential via the Draize test has been extensively criticized. In that regard, a great number of in vitro alternatives have been developed. Erythrocytes were chosen as the target cells for eye irritation assessment and hemolysis and hemoglobin denaturation were selected as appropriate endpoints. For skin irritancy assessment, the keratinocyte cell line NCTC 2544 was used and different in vitro endpoints were measured: two cytotoxicity assays (NRU and MTT) and the synthesis of the proinflammatory cytokine IL-1alpha. The eye and skin Draize tests were also performed for comparative purposes. The results point out that, according to in vivo and in vitro assays, the new arginine-derivative surfactants have lower eye and skin irritation potential than the synthetic surfactant SDS. Furthermore, in vitro methods were also able to detect differences in irritancy among the new surfactants not noticeable by the Draize tests, indicating that in vitro methods can be more sensitive than the in vivo test, offering the opportunity to detect subtle differences in irritancy.

Animal Testing Alternatives↗

PubMed2006

The chorioallantoic membrane test as a model to predict the potential human eye irritation induced by commonly used laboratory solvents.

The purpose of this study was to investigate the potential eye irritation of a range of solvents, extensively used in industry and laboratory and the capacity of the chorioallantoic membrane test to predict this eye irritation. The irritation has been evaluated by an in vitro method using the chorioallantoic membrane as an alternative to in vivo Draize rabbit test. All the solvents studied are potentially strongly irritants, even though diluted, except dimethyl sulfoxide which was moderately irritant at a concentration of 10% v/v. In some cases there is a correlation between the concentration of the solvent and the potential eye irritation induced. The method allows prediction of the potential eye irritation of the solvents studied.

Animals↗

PubMed2006

Oligomers are not the limiting factor in the absorption of DL-2-hydroxy-4-(methylthio)butanoic acid in the chicken small intestine.

The methionine hydroxy analogue DL-2-hydroxy-4-(methylthio)butanoic acid (HMB) is commonly used as a supplemental source of methionine in commercial animal diets. The HMB free acid is an aqueous solution that contains 88% product in an equilibrium mixture of monomer, dimer, and polymeric compounds. The present study examines whether the presence of these nonmonomeric forms reduces the absorption of the hydroxy analogue in the chicken small intestine. In vivo and in vitro methodologies were used to compare the intestinal absorption of an HMB product containing mainly monomer (HMB-PCM) with commercial HMB. The results from the in vivo perfusion of the jejunum showed no significant differences between the 2 hydroxy analogue sources in monomer absorption from the intestinal lumen, tissue accumulation, or plasma concentration. The results also indicate that the nonmonomeric forms are hydrolyzed during perfusion. Moreover, monomer tissue accumulation in everted sacs showed no significant differences between substrates, either in the presence or in the absence of a H+-gradient; a higher value was observed in the jejunum and ileum in comparison with the duodenum. Similarly, serosal appearance in H+-gradient conditions did not differ significantly between substrates, and it showed the same regional profile as in tissue accumulation. Oligomer hydrolysis was confirmed in vitro without significant differences between segments. In conclusion, the presence of nonmonomeric forms is not a limiting factor in HMB absorption, apparently because of the hydrolytic capacity of intestinal mucosa, as confirmed by experiments in vivo and in vitro.

Animal Feed↗

PubMed2005

Potential irritation of lysine derivative surfactants by hemolysis and HaCaT cell viability.

Surfactants represent one of the most common constituents in topical pharmaceutical and cosmetic applications or cleansers. Since adverse skin and ocular reactions can be caused by them, it is important to evaluate damaging effects. Amino acid-based surfactants deserve particular attention because of their low toxicity and environmental friendly properties. New lysine derivative surfactants associated with heavy and light counterions were tested. The ocular irritancy was assessed by hemolysis, and photohemolysis was employed to evaluate their phototoxicity. Cytotoxicity on HaCaT cells was determined by neutral red uptake and MTT assay to predict skin irritation. All lysine derivative surfactants were less hemolytic and thus less eye-irritating than the commercial surfactants used as model irritants. No phototoxic effects were found. All surfactants presented cytotoxic effects as demonstrated by decrease of neutral red uptake and reduction of MTT salt, with clear concentration-effect profiles. However, the rates of cytotoxicity on HaCaT for the new surfactants suggested that they were less cytotoxic and then, less skin-irritating than the reference ones; surfactants with heavy counterions were the less cytotoxic. The anionic surfactants investigated in the present work may constitute a promising class of surfactants given their low irritancy potential for pharmaceutical and cosmetic preparations.

Betaine↗

PubMed2004

Assessment of primary eye and skin irritants by in vitro cytotoxicity and phototoxicity models: an in vitro approach of new arginine-based surfactant-induced irritation.

Extensive efforts have been made, recently, to find surfactants with lower irritation potential than those presently commercially available, for use in pharmaceutical and cosmetic preparations. Cytotoxic and phototoxic effects of a novel family of dicationic arginine-diglyceride surfactant compounds, 1,2-diacyl,3-O-(l-arginyl)-rac-glycerol with alkyl chain lengths in the range from 8 to 14 carbon atoms, were compared to three commercial surfactants. The end-points used to assess toxicity were the red blood cell lysis assay and uptake of the vital dye neutral red 24h after dosing (NRU), respectively. Two immortalized cell lines, murine fibroblast cell line, 3T3, and one human keratinocyte cell line, HaCaT, were used as in vitro models to predict the potential phototoxicity which could result in irritation, determined by resazurin reduction to resorufin and neutral red uptake (NRU). All tested surfactants had cytotoxicity effects as demonstrated by and decrease of NR uptake, which showed a clear concentration-response relationship. Concentrations resulting in 50% inhibition of NR uptake (IC(50)) range from 1 microM(-1) (hexadecyl trimethyl ammonium bromide) to 565 microM(-1) (12,12-l-arginine). Erythrocyte haemolysis also showed a clear concentration-response relationship, the 50% of haemolysis ranged from 37 microM(-1) (10,10-l-arginine) to 151 microM(-1) (sodium lauryl sulphate). Phototoxicity was performed with 12,12-l-acetyl-arginine, the most stable chemical structure. The validated 3T3 NRU photoxicity assay was used and revealed a phototoxic potential.

Animal Testing Alternatives↗

PubMed2004

Potential eye irritation of some "biodegradable" liquid scintillation cocktails determined in vitro.

The potential eye irritation of a range of liquid scintillation cocktails has been evaluated by an in vitro method using the chorioallantoic membrane as an alternative to the Draize rabbit test. All the cocktails studied are potentially moderately to strongly irritant. The only slightly irritant product was Solventgreen, which is a solvent used in some of the cocktails. There is a correlation between the concentration of the cocktail and the potential eye irritation induced. Manufacturers of chemicals including liquid scintillation cocktails should accept responsibility for disclosing data about the composition and toxicity of their products with regard to waste disposal and safety of laboratory staff.

Animal Testing Alternatives↗

PubMed2004

Assessment of the potential skin irritation of lysine-derivative anionic surfactants using mouse fibroblasts and human keratinocytes as an alternative to animal testing.

PURPOSE: The aim of this study was to identify new surfactants with low skin irritant properties for use in pharmaceutical and cosmetic formulations, employing cell culture as an alternative method to in vivo testing. In addition, we sought to establish whether potential cytotoxic properties were related to the size of the counterions bound to the surfactants. METHODS: Cytotoxicity was assessed in the mouse fibroblast cell line 3T6 and the human keratinocyte cell line NCTC 2544 using the MTT assay and uptake of the vital dye neutral red 24 h after dosing (NRU). RESULTS: Lysine-derivative surfactants showed higher IC50s than did commercial anionic irritant compounds such as sodium dodecyl sulfate, proving to be no more harmful than amphoteric betaines. The aggressiveness of the surfactants depended on the size of their constituent counterions: surfactants associated with lighter counterions showed a proportionally higher aggressivity than those with heavier ones. CONCLUSIONS: Synthetic lysine-derivative anionic surfactants are less irritant than commercial surfactants such as sodium dodecyl sulfate and hexadecyltrimethylammonium bromide and are similar to betaines. These surfactants may offer promising applications in pharmaceutical and cosmetic preparations, representing a potential alternative to commercial anionic surfactants as a result of their low irritancy potential.

Animal Testing Alternatives↗

PubMed2001

Possible effects of counterions on biological activities of anionic surfactants.

The aggressiveness in terms of apogenic and necrotic activities of lysine-derived anionic surfactants towards a mammalian cell line (U937) were studied. We used N(alpha)N(epsilon)-dioctanoyl lysine as the model surfactant with lysine, tris, Na(+) or Li(+) as counterions. The aggressiveness of the different surfactants was assessed as the concentrations leading to apoptosis or necrosis after the cells were incubated in the presence of surfactants and then cultivated in their absence. Used in the same conditions, acetates associated with the same cations, had no effects on the cells. Our results show that the aggressiveness of the surfactants depended on the nature of the counterions: it was high when surfactants were associated with small counterions, and low with large counterions.

Anions↗

PubMed2001

Study of Ligmed-A, an antidiarrheal drug based on lignin, on rat small intestine enzyme activity and morphometry.

This study aimed to determine the potential toxic effect of 4-day oral treatment with a lignin-based formulation on the enzymatic activity and morphology of the small intestine of rat. Ligmed-A is collected from sugarcane and is used to treat diarrhea in weaning pigs. The compound is about 90% lignin, an insoluble polyphenolic constituent of plants and a component of dietary fiber. The duodenal, jejunal and ileal mucosa of control rats and those receiving 2 g/kg Ligmed-A showed similar protein contents of about 100 mg/g. The sucrase and alkaline phosphatase activities of the three intestinal segments were unaltered after administration of the compound. Nonhistological alterations were observed after treatment. Our results, together with those of previous studies which found no toxicological effects, indicate that Ligmed-A could provide a potent antidiarrheal treatment in the veterinary area. However, further studies are required to examine its use in humans.

Administration, Oral↗

PubMed2000

The quantitive chlorioallantoic membrane test using trypan blue stain to predict the eye irritancy of liquid scintillation cocktails.

The chorioallantoic membrane-trypan blue staining assay (CAM-TBS) is used to evaluate the potential ocular irritation caused by liquid scintillation cocktails constituted by complex mixtures, including surfactants and other potential irritants. The harmful effect of these substances is determined by the amount of trypan blue adsorbed by the CAM. In the membrane previously treated with the scintillation liquids this amount was concentration dependent only in certain cases, irrespective of the water solubility of the mixtures. In general, it showed a high correlation (r=0.986) with the scores obtained in the Draize eye irritation test. In the present study, only two cocktails presented values of trypan blue adsorption higher than those recorded for their eye irritation in vivo, irrespective of the solvent nature. Unlike the classical HET-CAM procedure, this assay is objective and allows the evaluation of opaque and coloured substances without interfering in the determination of irritancy. Despite these advantages, the method is not suitable for complex mixtures of products that induce ocular irritation in small quantities.

Allantois↗

PubMed1999

Erythrocyte hemolysis and shape changes induced by new lysine-derivate surfactants.

The effects of new synthetic lysine-derived anionic surfactants on human and rat erythrocytes were studied. The surfactants were salts of Nalpha,Nepsilon-dioctanoyl lysine with different counterions: lysine (77KK), tris (trishydroxymethyl amminomethane) (77KT), sodium (77KS), and lithium (77KL). 77KK and 77KT showed a biphasic hemolytic behavior in the erythrocytes. The surfactants 77KS and 77KL showed concentration-dependent hemolysis with a CH50 of about 3.4 and 2.6 mmol/l, respectively. 77KK and 77KT induced protection against hypotonic hemolysis in rat erythrocytes at the concentration which showed the least hemolytic activity under isotonic conditions. With human erythrocytes, 77KT did not show biphasic behavior in isotonic medium, but under hypotonic conditions biphasic behavior was present. Changes in shape of the erythrocyte, from discocytic to stomatocytic were observed after incubation with the anionic surfactants studied. Such shape changes occurred progressively over time, with total alteration in shape occuring after about 20 min of incubation.

Adult↗

PubMed1999

The relationship between the chain length of non-ionic surfactants and their hemolytic action on human erythrocytes.

The hemolytic action of monodisperse, non-ionic surfactants based on lysine containing two hydrophobic chains and one polyoxyethylene glycol chain of different length was studied in order to identify possible structure-activity relationships. In the series of the two polyoxyethylene glycol unit compound, the surfactant with a total of 18 carbon atoms in the hydrophobic chains was the most hemolytic. In the series the of four polyoxyethylene glycol unit compound, hemolytic activity decreases when the number of carbon atoms in the hydrophobic chain was increased. Increasing the length of the polyoxyethylene glycol chain in general reduces the hemolytic action of the surfactant.

Erythrocytes↗

PubMed1997

Alterations of male Wistar rat jejunum induced by Dodine (n-dodecylguanidine acetate).

The effect of Dodine on the intestine was studied after a single administration of 1000 mg/kg, which corresponds to the LD50 in male Wistar rats. At this dose, a significant decrease in body weight was observed, accompanied by diarrhea, which may be associated with intestinal alterations. The chemical induced a significant reduction of the protein content and in sucrase activity in the jejunum. Morphological alterations included a significant decrease in crypt height and in villus length and depth. The intestinal modifications observed in animals after Dodine administration may explain the observed loss in body weight and diarrhea.

Animals↗

PubMed1997

Hemolytic action of anionic surfactants of the diacyl lysine type.

Amphiphiles induce hemolysis at a given concentration and that would be dependent on their structure. To know this, we have synthesized anionic surfactants derived from lysine and differing in their chain length and we have studied their hemolytic action. The chain length of the surfactants affects their hemolytic behaviour. Surfactants with two chains of 7 or 9 carbons presented biphasic behaviour at a concentration below or above 50 mg/100 ml. However, only the surfactant with two chains of 7 carbons has a protective effect against hypotonic hemolysis. The maximum protection was exerted when the surfactant was added to a 150 mOsmol/L solution. The surfactant is assumed to intercalate into the membrane in an orientated fashion and prevent the hypotonic hemolysis. For this hemolytic behaviour the presence of two chains of 7 carbons seems to be necessary.

Acylation↗

PubMed1996

Preliminary studies of the toxic effects of non-ionic surfactants derived from lysine.

The toxic effects of new synthetic monodisperse non-ionic long-chain N alpha, N epsilon-diacyl lysine polyoxyethylene glycol amide compounds with a structural resemblance to natural lecithin phospholipids were studied by the haemolytic method and the test of the chorioallantoic membrane of the hen's egg (HET-CAM). The following compounds were tested: symmetrical N alpha,N epsilon-diacyl lysine homologues (N alpha,N epsilon-dihexanoyl, N alpha,N epsilon-dioctanoyl and N alpha,N epsilon-didecanoyl lysine) with one methyl ether polyoxyethylene glycol chain of different oxyethylene units (dioxyethylene glycol, tetraoxyethylene glycol and hexaoxyethylene glycol) as headgroup; symmetrical N alpha,N epsilon-diacyl lysine homologues with two methyl ether dioxyethylene glycol chains and the asymmetrical N alpha-butanoyl, N epsilon-dodecyl lysine with two hydrophilic methyl ether dioxyethylene glycol chains as headgroup. A commercial (polydisperse) oleoyl polyoxyethylene glycol diethanolamide with an average of eight units of ethylene oxide was used as control. All the synthesized tested compounds appeared to be less haemolytic and less irritant than the control. The synthesized products were studied with regard to their hydrophobic and hydrophilic chains in order to evaluate the influence of their structure on their haemolytic and irritative action. The results of this study show that the acyl chain distribution of these compounds greatly influence toxic effects: the asymmetrical compound N alpha-butanoyl,N epsilon-dodecyl lysine-bis[methyl ether diethylene glycol]amide was found to be the most haemolytic and irritating compound. Among the symmetrical homologues, the shortest-chain compounds N alpha,N epsilon-dihexanoyl lysine methyl ether polyoxyethylene glycol amides present the least haemolytic and irritating activity, independently of the number and length of the hydrophilic methyl ether polyoxyethylene glycol chains. Taking into account their surface activity properties and their less haemolytic and irritant action, the compound N alpha,N epsilon-dioctanoyl lysine-bis[methyl ether diethylene glycol]amide would be the most suitable for practical purposes.

Allantois↗

PubMed1996

Ontogenetic development of proline intestinal transport in the domestic fowl.

1. The proline disappearance from the jejunal and ileal lumen of chickens aged from 1 day to 15 weeks were studied using a perfusion method "in vivo". 2. A decrease in proline transport was observed from younger to older animals. The 2 intestinal segments showed different behaviours, the 1-day and 1-week-old animals showed the same value in the jejunum, whereas in the ileum a progressive decrease in proline transport was observed from the first week of life. 3. The differences observed in the 2 segments could be attributed to the different rates of growth of the jejunum and ileum with age; the jejunum showed a peak of growth in the second week of life whereas the ileum showed a peak of growth in the first week. Proline transport in the jejunum decreased until the fifth week and remained constant thereafter.

Aging↗