The effect of vehicle on skin absorption of Mg2+ and Ca2+ from thermal spring water.

OBJECTIVE: Thermal spring waters (TSW) are commonly used as active ingredients in cosmetics. Their biological activities directly depend on the ionic composition of the spring. However, in order to exhibit beneficial properties, the minerals need to reach viable skin layers. The present study addresses the incorporation of marketed TSW in model cosmetic formulations and the impact of the formulation on skin absorption of magnesium and calcium ions that are known to improve skin barrier function. METHODS: Marketed TSW was introduced into five formulations. Liposomes were prepared using saturated or unsaturated phospholipids mixed with cholesterol by the thin layer evaporation technique. Emulsions water-in-oil (W/O), oil-in-water (O/W) or double: water-in-oil-in-water (W/O/W) were prepared by high-shear mixing. Skin absorption of Mg2+ and Ca2+ from those formulations was studied in vitro using static Franz diffusion cells under infinite dose condition and under occlusion of the apparatus. RESULTS: Mg2+ and Ca2+ penetrate skin samples from TSW. Encapsulating TSW into double emulsion (TSW/O/W) increased skin absorption of both cations of interest and kept the Ca2+ /Mg2+ ratio equal to that of TSW in each skin layer. The dermal absorption of Mg2+ from the double emulsion departs from both single emulsions. Application of liposome suspension improved the skin absorption of Ca2+ while keeping constant that of Mg2+ , leading to unbalanced Ca2+ /Mg2+ ratio inside skin. CONCLUSION: The beneficial effects of TSW are not only due to their action on the skin surface. Their active components, especially Ca2+ and Mg2+ cations, reach viable skin layers in a formulation-dependent manner. The distribution of ions inside skin depends on the type of formulation.

OBJECTIFS: Les eaux thermales sont couramment utilisées comme substances actives dans les formulations cosmétiques. Leurs activités biologiques dépendent directement de leur composition en ions. L'action des ions s'exerce à différents niveaux dans la peau, mais bien souvent dans les couches profondes, au-delà du stratum corneum, qu'ils doivent donc atteindre. L'objectif de cet article est d'étudier l'absorption des ions magnésium et calcium, reconnus pour leur effet bénéfique sur la fonction barrière de la peau, depuis différentes formes galéniques formulées avec une eau thermale. METHODES: Une eau thermale commerciale a été utilisée comme phase aqueuse dans 5 formulations différentes : des liposomes formulés avec des phospholipides saturés et insaturés et du cholestérol ; des émulsions de différents sens, eau thermale/huile (TSW/O) et huile/eau thermale (O/TSW) ; une émulsion multiple eau thermale/huile/eau (TSW/O/W). L'absorption cutanée du calcium et du magnésium a été étudiée depuis ces différentes formulations, en utilisant la méthode des cellules de Franz, en dose infinie, et en fermant les cellules pour prévenir toute évaporation. RESULTATS: Les ions magnésium et calcium pénètrent dans la peau depuis l'eau thermale, utilisée comme contrôle. L'encapsulation de l'eau thermale dans les gouttelettes internes de l'émulsion double (TSW/O/W) permet de promouvoir la pénétration des deux ions d'intérêt dans chaque couche de la peau tout en respectant le rapport Ca2+ /Mg2+ obtenu avec l'eau thermale, contrairement aux émulsions simples. Les liposomes augmentent la pénétration cutanée des ions calcium, tandis que celle des ions magnésium reste constante, ce qui conduit à des rapports Ca2+ /Mg2+ élevés dans la peau. CONCLUSION: Les effets thérapeutiques des eaux thermales ne sont pas seulement dus à une action de surface. Les ions comme le calcium et le magnésium pénètrent dans la peau et exercent une action en profondeur qui dépend de la formulation dans laquelle ils sont formulés. En effet, leur distribution ions dépend de la formulation qui les contient.

Formulation of survival acceptor medium able to maintain the viability of skin explants over in vitro dermal experiments.

OBJECTIVE: In vitro assessments of skin absorption of xenobiotics are essential for toxicological evaluations and bioavailability studies of cosmetic and pharmaceutical ingredients. Since skin metabolism can greatly contribute to xenobiotic absorption, experiments need to be performed with skin explants kept viable in suitable survival media. Existing protocols for non-viable skin are modified to consider those conditions. The objective was to design a survival medium used as an acceptor fluid in Franz cells for testing cutaneous penetration of hydrophilic or lipophilic molecules. Their metabolism inside skin may be investigated under the same conditions. The determining factors involved in survival mechanisms in vitro are discussed. The consequences of short-term skin preservation at 4°C were also evaluated. METHODS: The metabolic activity of fresh skin samples mounted in Franz cells was studied by measurement of lactate release over 24 h in order to assess the impacts of pH, buffering, osmolality, ionic strength, initial glucose supply and the addition of ethanol or non-ionic surfactant in the acceptor part of Franz cells. CONCLUSION: Survival media must maintain physiological pH (>5.5) be isotonic with skin cells (300 mOsm kg-1 ) and contain at least 0.5 g L-1 glucose. Several compositions able to preserve skin metabolism are reported. Storage of skin explants overnight at 4°C impairs skin metabolic activity. The present work provides guidelines for designing survival media according to constraints related to the scientific requirements of the experiments.

OBJECTIFS: Les études d'absorption cutanée sont indispensables pour les évaluations toxicologiques et les études de biodisponibilité des ingrédients cosmétiques et pharmaceutiques. Etant donné que le métabolisme cutané peut contribuer à l'absorption cutanée des xénobiotiques, les études doivent être parfois menées sur les explants cutanés maintenus en survie à l'aide d'un milieu adapté. Les protocoles classiques utilisés avec des explants congelés non viables sont souvent modifiés pour prendre en compte ces conditions particulières. L'objectif de cette étude est d'étudier les conditions nécessaires à appliquer au milieu receveur des cellules de Franz pour maintenir la viabilité des explants, dans les études de pénétration cutanée de molécules hydrophiles et lipophiles. Leur métabolisme dans la peau peut être étudié dans ces mêmes conditions. Les facteurs déterminants à prendre en compte pour assurer la viabilité des explants in vitro sont discutés. Les conséquences de la conservation des explants cutanés durant une courte durée à 4°C, avant utilisation, ont été également évaluées. METHODES: L'activité métabolique des échantillons de peau, montés en cellules de Franz, a été évaluée grâce aux mesures du lactate produit durant 24h, durée de l'expérience. L'impact du pH, de solutions « tampon ¼, de l'osmolalité, de la force ionique, de la concentration initiale en glucose et de l'addition d'éthanol ou de tensioactifs non-ioniques, dans le milieu receveur de la cellule de Franz, a été étudié. CONCLUSION: Le milieu de survie doit maintenir un pH physiologique (>5.5), être isotonique par rapport aux cellules de la peau (300 mOsm kg-1 ) et contenir au moins 0.5 g L-1 de glucose. Plusieurs compositions capables de maintenir le métabolisme cutané sont décrites. La conservation des explants cutanés à 4°C, durant une nuit, perturbe l'activité métabolique de la peau. Ces travaux permettent de mettre en évidence des prérequis pour la formulation de milieux de survie adaptés aux expériences.

Can contamination of the environment by dioxins cause craniofacial defects?

Cleft lip and cleft palate also known as orofacial cleft is a congenital malformation involving the partial or total lack of anatomical continuity of craniofacial tissue. The most common environmental factors that may cause orofacial clefts include pharmaceuticals, alcohol, addictive drugs, and tobacco smoke. Living in the area of industrial factories, garbage, ironworks, crematoria, wastewater treatment plants, and plastic waste landfills also has a significant impact on the development of the craniofacial defects. Some of the main factors causing the formation of congenital craniofacial defects are dioxins, of which emission to the environment is an important environmental and health problem. Dioxins are a diverse group of organic chemical compounds, derivatives of oxanthrene and fumarates, which are organoleptically imperceptible. Acting mainly through induction of inflammation, they influence a number of metabolic processes, including the process of bone mineralization and embryonic development. In this work, we highlight the problem of orofacial cleft including the impact of dioxin on development of this defect and the recommended prevention.

[Cholecystolithiasis in the urban population of Poland]. / Kamica pecherzyka zólciowego w populacji miejskiej w Polsce.

Multicentre study was carried out in three regions of Poland aimed to assess cholecystolithiasis incidence in urban population and some potential risk factors of the disease. 10133 persons in five age groups, from 16 to 70 (6071 women and 4062 men) were examined. The examination consisted of questionnaire considered sex, age, weight, dietary habits, complaints, chronic drugs use, family history and in women number of pregnancies and deliveries as well as hormone therapy. The results obtained were analysed statistically with Chi 2 test. Cholecystolithiasis was found in 1411 persons (10.7%), among them 18% women (1083 women) and 8.2% men (328 men). Incidence rate was 180.5/1000 women and 82.0/1000 men. The obtained increase in percentage of cholecystolithiasis cases with age was statistically significant. No relation were found between the number of stones and sex of the examined persons. In 1480 persons (43.5%0 the disease was asymptotic. The studies did not prove the correlation between cholecystolithiasis in women and sex of the first child or oral contraception. Positive correlation was found between cholecystolithiasis in women, obesity, number of pregnancies and family history. In men age was most significant risk factor. Incidence of cholecystolithiasis in Poland, Western Europe and USA is similar.

[Incidence of cholecystolithiasis in women employed by industrial workplaces in Szczecin]. / Czestosc wystepowania kamicy pecherzyka zólciowego u kobiet zatrudnionych w zakladach przemyslowych Szczecina.

Making use of the possibility that is provided by the ultrasonic technique applied for epidemiological examinations of cholelithiasis, 1339 women, aged 20-69 years, employed at two "typical feminine" working places in Szczecin were investigated. The purpose of the paper was to perform sonographic studies of the gallbladders in women employed in "typical feminine" clothing industry establishments of Szczecin, in order to estimate the incidence rate of cholecystolithiasis in the studied population--types of cholelithiasis risk factors,--relationship between the changes revealed at sonographic examination and clinical symptoms. Cholelithiasis was diagnosed in 232 women, i.e. in 17.33% of the examined. The incidence rate was rising with the age from 1.66% of cases among those aged 20-29 years to 35.29% among women 60-69 years old. Successive significant risk factors appeared to be overweight in as many as 72.8% of the studied females with calculosis, and also past three or more pregnancies and miscarriages. The use of oral anticonceptive drugs as well as positive family anamnesis was of lesser, but of significant importance. Asymptomatic calculosis was disclosed in 173, whereas the other 273 studied women were found to have symptomatic calculosis. No relation was recorded between the number as well as the size of deposits in the gallbladders, and the presence of ailments or their absence. More frequent incidence of cholelithiasis in female population was encountered than that reported by West-European authors. Also more frequent appearance of symptomatic calculosis was evidenced than it is generally published in literature.

MNDO study of the mechanism of the inhibition of cysteine proteinases by diazomethyl ketones.

Diazomethyl ketones are one of the most effective irreversible inhibitors of cysteine proteinases and are therefore very important in drug design. In the present study a mechanism of inactivation is proposed based on the results of model MNDO calculations of the possible pathways. It was found that the mercaptide nucleophile, on approaching the carbonyl carbon as in the catalytic reaction path, binds to the inner diazo nitrogen. The intermediate thus formed can rearrange giving a stable product, beta-thioketone, and molecular nitrogen, with a considerable energy gain. The energy barrier to this process is equal to 36.9 kcal/mol, and corresponds to a pyramidal transition state with the vertex at the methylene carbon and the base formed by the carbonyl, thiol, and diazo groups. The energy barrier can be lowered on deprotonation of the intermediate. Based on the results obtained it was concluded that good irreversible inhibitors of cysteine proteases must fulfil two structural requirements: i) the dimensions and charge distribution must be similar to those of the peptide bond and ii) a second electrophilic center must be present in the neighbourhood of the carbonyl carbon. These are requirements which are satisfied by other strong cysteine proteinase inhibitors: beta-chloroketones and beta-ketooxiranes.

Investigation of the inhibition pathway of glucosamine synthase by N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid by semiempirical quantum mechanical and molecular mechanics methods.

Glucosamine synthase (E.C. 2.6.1.16) is a promising target in antifungal drug design. It has been reported that its potent inhibitor, N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP), inactivates the enzyme by the Michael addition of the S-H group to the FMDP molecule followed by cyclisation reactions. In this study we have investigated, by means of semiempirical MNDO, PM3 and molecular mechanics methods, the energetics and kinetic possibility of the formation of various stereoisomers of the products of cyclisation of the Michael addition products detected experimentally. It was found that the substituted 1,4-thiazin-3-one can be formed in one step under alkaline conditions; the stereoisomers of this compound predicted to be the most stable on the basis of theoretical calculations are also the dominant ones in reality.

A theoretical study of glucosamine synthase. II. Combined quantum and molecular mechanics simulation of sulfhydryl attack on the carboxyamide group.

Continuing our theoretical studies of glucosamine synthase catalysis, we have carried out MNDO and ab initio calculations of the first stage of the reaction, which involves the attack of a cysteine thiol group from the enzyme active site on the side chain carboxyamide group of glutamine, producing ammonia and thioester. The reactants were modelled by methyl mercaptate and acetamide, respectively. For two considered mechanisms of the reaction the energy surfaces were evaluated. Mechanism I, proposed by Chmara et al. (1985) involves the nucleophilic attack of a deprotonated thiol group on the carbonyl carbon atom. Mechanism II, postulated in our previous work (Tempczyk et al. 1989), assumes the concerted binding of the mercaptate sulphur to the carbonyl carbon and the sulfhydryl hydrogen to the amide nitrogen with simultaneous breaking of the S-H bond. The energy surface of mechanism I shows no minimum on the approach of the mercaptide anion towards the carbonyl carbon, which is also consistent with ab initio calculations in a 4-31 G basis set. Therefore, mechanism I seems to be unlikely. The same analysis of mechanism II shows that it leads to the desired products: methyl thioacetate and ammonia. The presence of a sulfhydryl hydrogen causes apparent pyramidicity of the amido nitrogen and lengthening of the C-N bond in the transition state, making conditions for the release of the ammonia molecule. The MNDO calculated energy barrier of the reaction is 50.1 kcal/mol and the approximate 4-31 G ab initio barrier (at the MNDO geometries of the substrate complex and the transition state) is 63 kcal/mol.(ABSTRACT TRUNCATED AT 250 WORDS)

A theoretical study of glucosamine synthase. Part I. Molecular mechanics calculations on substrate binding.

Glucosamine synthase transfers the gamma-amino group of glutamine to fructose, producing 1-glucosamine which is the key constituent of bacterial and fungal cell walls. In this study, model calculations were performed on substrate binding to the enzyme active site. Two models of the active site of glucosamine synthase were proposed, which assume two different sequences of aminoacids, Cys-Gly-Ile and Cys-Ala-Cys, the first one being the N-terminal sequence of the Escherichia coli enzyme. Several initial geometries were assumed for these tripeptides, the energy was then optimized by means of molecular mechanics. It has been found that the structure which is both energy optimal and satisfies the assumed cysteine sulphur arrangement consists of combinations of C7eq and C7ax conformations of single residues. Molecular mechanics calculations were then performed on glutamine and D-fructose-6-phosphate, which are the substrates of the enzymatic catalysis, and on their complex with the enzyme glutamine-binding site. The spatial configuration of the compounds under study, which is optimal as far as the reaction path is concerned, also turned out to be an energy minimum.