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[The death of moulages - wax figures in dermatology].

Wax has been used for illustration purposes back to antiquity. Since the renaissance period human anatomy and different diseases have often been depicted in wax. During the last century the art of moulage preparation evolved to three-dimensional, realistic representations of diseased parts of the human body. Its heyday and wide spread distribution paralleled the growing independence of dermatology. Apart from few exceptions, most mouleurs did not permit access to their technique either to successors or the public. Just like other European hospitals, the Department of Dermatology at Kiel University houses a comprehensive collection of moulages dating back to a century. The 455 objects left today were collected by Professor Viktor Felix Karl Klingmüller (1870-1942) who was head of the department from 1906 to 1937. The mouleur Alfons Kröner from Breslau who died 1937 supplied most (354) of the wax models. Highly esteemed at his time, Kröner was quite secretive about his art of moulagig. 35 of his moulages bear the abbreviation "DRP" standing for Deutsches Reichspatent (German patent); Kröner was granted a patent in 1902. In his patent application both wax mixtures and technical procedure of moulaging are described in great detail. Kröner, similarly to Jules Baretta (Paris), coloured his moulages at the back of the wax layers. Applying for a patent demonstrates his effort to meet increasing commercial pressure among suppliers of teaching aids at that time. Knowledge of individual technical procedures is essential for medical history as well as proper restauration of moulages as they continually deteriorate with time. Because of their three-dimensional and realistic disease representations, moulages still compare well to modern media used today. Consequently, the "dying of moulages" concerning the wax objects themselves as well as public or medical interest has to be stopped to preserve moulages for future generations.

Dermatology↗

Non destructive analysis of the wax layer of apple (Malus domestica Borkh.) by means of confocal laser scanning microscopy.

Confocal laser scanning microscopy (CLSM) was used to non-destructively analyse the changes in the structure and thickness of the cuticle during storage of apples (Malus domestica Borkh.). Interpretation of the confocal images was performed by comparison with scanning electron microscopy and environmental scanning electron microscopy images. The natural reflectance of the wax and the auto-fluorescence of the underlying cells made it possible with CLSM to distinguish the wax from the underlying layers without any pretreatment of the fruit. The thickness of the consecutive layers (wax, cutin, cells) could be estimated from measurements of the reflection and fluorescence intensities as a function of the number of pixels. The mean wax-layer thickness measured in this way amounted to 2.58 microm, 3.41 microm or 4.14 microm for the cultivars Jonagold, Jonagored and Elstar, respectively. Changes in the wax structure and cells of the same important Belgian apple cultivars as mentioned above were monitored during nine months of storage in ultra low oxygen and after exposure to ambient conditions. The changes in the wax ultrastructure and cell morphology are likely related to water losses and specific protection of the apple cultivars against water losses during storage and shelf life.

Fruit↗

Wax ester-synthesizing activity of lipases.

The synthesis/hydrolysis of wax esters was studied in an aqueous solution using purified rat pancreatic lipase, porcine pancreatic carboxylester lipase, and Pseudomonas fluorescens lipase. The equilibrium between wax ester synthesis and hydrolysis favored ester formation at neutral pH. The synthesizing activities were measured using free fatty acid or triacylglycerol as the acyl donor and an equimolar amount of long-chain alcohol as the acyl acceptor. When oleic acid and hexadecanol emulsified with gum arabic were incubated with these lipases, wax ester was synthesized, in a dose- and time-dependent manner, and the apparent equilibrium ratio of palmityl oleate/free oleic acid was about 0.9/0.1. These lipases catalyzed the hydrolysis of palmityl oleate emulsified with gum arabic, and the apparent equilibrium ratio of palmityl oleate/free oleic acid was also about 0.9/0.1. The apparent equilibrium ratio of wax ester/free fatty acid catalyzed by lipase depended on incubation pH and fatty alcohol chain length. When equimolar amounts of trioleoylglycerol and fatty acyl alcohol were incubated with pancreatic lipase, carboxylester lipase, or P. fluorescens lipase, wax esters were synthesized dose-dependently. These results suggest that lipases can catalyze the synthesis of wax esters from free fatty acids or through degradation of triacylglycerol in an aqueous medium.

Adenosine Triphosphate↗

Sputum wax-worms after plombage.

Paraffin wax plombage was one of several plombage operations used for pulmonary tuberculosis about 40 years ago, and Shepherd included seven patients treated with wax plombage in her review of plombage in 1985. We describe another patient with wax plombage who coughed up wax 28 years after plombage, followed by much larger amounts of wax 15 years later. The pieces of wax were like worms and spirals, and we discuss possible causes for these shapes.

Aged↗

Total internal reflection Raman spectroscopy of barley leaf epicuticular waxes in vivo.

The use of total internal reflection (TIR)-Raman spectroscopy to examine cuticular wax layers in vivo at the surface of barley leaves (Hordeum vulgare L. cultivar Pastoral) is demonstrated. The limited penetration depth (40 nm) of the evanescent wave compared to the thickness of the wax layer eliminates problems arising from fluorescence from underlying pigments. Epicuticular wax crystals are observed to be more crystalline than the amorphous wax layer, which is analysed after removal of the wax crystals by cellulose acetate stripping. Carotenoids are detected as trace species in the cuticular waxes.

Hordeum↗

Physical stability, centrifugation tests, and entrapment efficiency studies of carnauba wax-decyl oleate nanoparticles used for the dispersion of inorganic sunscreens in aqueous media.

Aqueous nanoscale lipid dispersions consisting of carnauba wax-decyl oleate mixtures acting as carriers or accompanying vehicles for inorganic sunscreens such as barium sulfate, strontium carbonate, and titanium dioxide were prepared by high pressure homogenization. For the manufacture of these nanosuspensions, three pigment concentrations (%wt), namely 2, 4, and 6, and two carnauba wax-decyl oleate ratios, 1:1 and 2:1, were used, being some of these combinations chosen for stability studies. Six-month physical stability tests at 4, 20, and 40 degrees C selecting the mean particle size and the polydispersity index of the nanosuspensions as reference parameters were performed. Centrifugation tests of the nanosuspensions assessed by transmission electron microscopy and by the determination of the content of pigments and carnauba wax in the separated fractions were done. The mean particle sizes and the polydispersity indices of the nanosuspensions were not altered after six-month storages at 20 and at 40 degrees C. However, the storage of those at 4 degrees C considerably increased the particle size and polydispersity of the systems, particularly when wax-oil ratios (2:1) were used for the entrapment of the pigments. Transmission electron micrographs of centrifuged samples denoted the presence of three major fractions showing the different types of particles integrated into the nanosuspensions. Furthermore, it was observed that not all the carnauba wax participated in the entrapment of the pigment. Regarding the amount of pigment being encapsulated or bonded by the wax-oil matrices, entrapment efficiencies higher than 85.52% were reported.

Centrifugation↗

Wax constituents on the inflorescence stems of double eceriferum mutants in Arabidopsis reveal complex gene interactions.

To shed new light on gene involvement in plant cuticular-wax production, 11 eceriferum (cer) mutants of Arabidopsis having dramatic alterations in wax composition of inflorescence stems were used to create 14 double cer mutants each with two homozygous recessive cer loci. A comprehensive analysis of stem waxes on these double mutants revealed unexpected CER gene interactions and new ideas about individual CER gene functions. Five of the 14 double cer mutants produced significantly more total wax than one of their respective cer parents, indicating from a genetic standpoint a partial bypassing (or complementation) of one cer mutation by the other. Eight of the 14 double cer mutants had alkane amounts lower than both respective cer parents, suggesting that most of these CER gene products play a major additive role in alkane synthesis. Other results suggested that some CER genes function in more than one step of the wax pathway, including those associated with sequential steps in acyl-CoA elongation. Surprisingly, complete epistasis was not observed for any of the cer gene combinations tested. Significant overlap or redundancy of genetic operations thus appears to be a central feature of wax metabolism. Future studies of CER gene product function, as well as the utilization of CER genes for crop improvement, must now account for the complex gene interactions described here.

Arabidopsis↗

Cuticular waxes from potato (Solanum tuberosum) leaves.

The qualitative and quantitative compositions of leaf cuticular waxes from potato (Solanum tuberosum) varieties were studied. The principal components of the waxes were very long chain n-alkanes, 2-methylalkanes and 3-methylalkanes (3.1-4.6 microg cm(-2)), primary alcohols (0.3-0.7 microg cm(-2)), fatty acids (0.3-0.6 microg cm(-2)), and wax esters (0.1-0.4 microg cm(-2)). Methyl ketones, sterols, beta-amyrin, benzoic acid esters and fatty acid methyl, ethyl, isopropyl and phenylethyl esters were found for the first time in potato waxes. The qualitative composition of the waxes was quite similar but there were quantitative differences between the varieties studied. A new group of cuticular wax constituents consisting of free 2-alkanols with odd and even numbers of carbon atoms ranging from C25 to C30 was identified.

Alcohols↗

Study on the surface of resins that burn without residues in the lost-wax procedure.

STATEMENT OF PROBLEM: When compared with waxes and prefabricated components made of dental alloys, processing resins is difficult and often results in a less accurate fit. The exact linear dimension is hard to realize, as the materials required for a dental casting are adjusted to dental waxes, and usually there are no special processing instructions for these resins. PURPOSE: The surface structure of 16 residue-free burning resins was determined to find which could enlarge the range of application for waxes in the dental casting technique. MATERIAL AND METHODS: A total of 480 specimens (30 castings for each of 16 resins) were marked with an individually cut pyramid, which left an impression in the resin. This was distinctly visible in the metal after casting in "the lost form." The surfaces of these 480 specimens were measured in three dimensions with a positioning aid "before casting in resin" and "after casting in metal" by the Perthometer micrometer. All specimens were treated identically by the lost-wax process by using the rotation symmetry of the muffle. The differences in the surface data before casting in resin and after casting in metal characterize the quality of the particular resin. RESULTS: Surface roughness differed between the 16 resins in the range of micrometer. CONCLUSIONS: With the dental casting technique, it is recommended that some resins replace waxes or wax-resin compositions.

Dental Alloys↗

Cuticular waxes on eceriferum mutants of Arabidopsis thaliana.

We present cuticular wax chemical profiles for the leaves and stems of Arabidopsis wildtype Landsberg erecta and eleven isogenic eceriferum mutants: cer5, cer10 to cer15, and cer17 to cer20. These cer mutants have wax profiles that are different from those of wildtype in chemical chain length distribution, amount per chemical class, and/or total wax load. Analyses of detailed leaf and stem wax profiles for these cer mutants have allowed us to place some of these mutants at specific steps in wax production. The cer13 gene is predicted to affect release of the 30 carbon fatty acid from the elongation complex or the reduction of C30 fatty acid to C30 aldehyde. The CER19 gene product is predicted to be involved in C28 to C30 fatty acyl-CoA elongation. The CER20 gene is predicted to affect the oxidation of C29 alkane to C29 secondary alcohol. Several predicted gene products affect only stem specific steps in the wax pathway.

Arabidopsis↗

Wax digestion by the lesser honeyguide Indicator minor.

Records of the lesser honeyguide feeding on beeswax in the wild are common. However, little is known about the ability of these birds to digest wax. We studied the wax preference, digestive efficiency, retention time and gut structure of the lesser honeyguide in the laboratory. Wax was found to be eaten daily by the lesser honeyguide. Birds ate significantly more new beeswax and foundation wax than old, black beeswax, but required an additional source of protein to maintain body mass. In the absence of other feed, the digestive efficiency for foundation wax was above 90%, with a long transit time of 256 min. Examination of the digestive tract showed no specialisation and no crop. The presence of digestive enzymes, including lipase, in the pancreas and small intestine and very few microbes in the digestive tract of the lesser honeyguide suggests that wax digestion occurs through a biochemical pathway with endogenous avian enzymes.

Animals↗

Novel wax esters and hydrocarbons in the cuticular surface lipids of the red harvester ant, Pogonomyrmex barbatus.

The cuticular surface lipids of the red harvester ant, Pogonomyrmex barbatus, were found to contain minor amounts of novel wax esters, in addition to the major components, hydrocarbons. The wax esters ranged in carbon number from C19 to C31 and consisted of esters of both odd- and even-numbered alcohols and acids. Each wax ester with a given carbon number eluted at several different retention times indicating possible methyl branching in either the fatty acid or alcohol moiety, or in both moieties. Each eluting peak of wax esters consisted of a mixture of wax esters of the same carbon number in which the fatty acid moiety ranged from C8 to C18, and the alcohol moiety ranged from C8 to C17. Some wax esters were largely found on the head indicating they may be of a glandular origin. The hydrocarbons consisted of: n-alkanes, C23 to C33; odd-numbered n-alkenes, C27 to C35; and the major components, methyl-branched alkanes, C26 to over C49. Notable components of the methyl-branched alkanes were 2-methyltriacontane, and the novel trimethylalkanes with a single methylene between the first and second branch points, 13,15,19-trimethylhentriacontane and 13,15,21-trimethyltritriacontane.

Animals↗

Phototransformation of the herbicide sulcotrione on maize cuticular wax.

Vegetation plays a key role in environmental cycling and the fate of many organic pollutants. This is especially the case for pesticides because plant leaves are their first reaction environment after application. It is commonly accepted that photochemical reactions of pollutants on plants predominantly take place in the cuticular wax coating of the leaves. Thus, we used films made of either cuticular wax extracted from maize or carnauba gray wax as a model support. Under simulated sunlight irradiation, sulcotrione (a new class of triketone herbicides) sorbed on cuticular wax films was photolyzed and mainly underwent an intramolecular cyclization. The photoproduct is a chromone derivative which was isolated and fully characterized. It is reported for the first time as a sulcotrione degradation product. The photoreactivity of formulated sulcotrione at the surface of cuticular waxes was investigated too. It photodegraded more rapidly than nonformulated sulcotrione. This study also shows that the rate of sulcotrione photolysis was much faster than the rate of penetration into the wax; photolysis should be, thus, a relevant process in real conditions.

Animals↗

Wax encapsulation of water-soluble compounds for application in foods.

Water-soluble ingredients have been successfully encapsulated in wax using two preparation techniques. The first technique ('solid preparation') leads to relatively large wax particles. The second technique ('liquid preparation') leads to relatively small wax particles immersed in vegetable oil. On the first technique: stable encapsulation of water-soluble colourants (dissolved at low concentration in water) has been achieved making use of beeswax and PGPR. The leakage from the capsules, for instance of size 2 mm, is about 30% after 16 weeks storage in water at room temperature. To form such capsules a minimum wax mass of 40% relative to the total mass is needed. High amounts of salt or acids at the inside water phase causes more leaking, probably because of the osmotic pressure difference. Osmotic matching of inner and outer phase can lead to a dramatic reduction in leakage. Fat capsules are less suitable to incorporate water soluble colourants. The reason for this could be a difference in crystal structure (fat is less ductile and more brittle). On the second technique: stable encapsulation of water-soluble colourants (encapsulated in solid wax particles) has been achieved making use of carnauba wax. The leakage from the capsules, for instance of size 250 mm, is about 40% after 1 weeks storage in water at room temperature.

Capsules↗

Effect of monosodium methanarsonate application on cuticle wax content of cocklebur and cotton plants.

Leaf cuticle waxes were extracted from monosodium methanearsonate (MSMA)-resistant (R) and -susceptible (S) common cocklebur (Xanthium strumarium L.) and cotton (Gossypium hirsutum L.) plants at 0, 3, 5, and 7 days after treatment (DAT) following 1x and 2x MSMA applications. Wax constituents were analyzed by gas chromatography (GC) with flame ionization detection and compared to alkane and alcohol standards of carbon lengths varying from C21 to C30. Differences in waxes were calculated and reported as change per ng mm2-1. Tricosane (C23) was found to increase following MSMA applications. All other alkanes decreased by 7 DAT, with some showing a linear effect over time in the R-cocklebur. Alcohol constituents were also observed to decrease by 7 DAT. Total arsenic in the extracted wax fraction was determined, with greatest quantities detected in the R-cocklebur. Wax changes are not believed to play a role in cotton tolerance, since changes in cuticle concentrations were minimal. Cocklebur resistance to MSMA is not due to cuticle constituents; the wax changes are a secondary effect in response to herbicide application.

Alcohols↗

Composition and seasonal variation of soluble cuticular waxes in Actinidia deliciosa leaves.

This research examines the annual evolution and composition of soluble cuticular waxes of Actinidia deliciosa Chev. cv Hayward leaves. Soluble cuticular waxes of foliar blade were extracted in chloroform and analysed by GC-MS. The seasonal weighted mean of the wax coverage was about 24 microg cm(-2). The alkyl alkanoates were the main class of components (10 microg cm(-2)) followed by hydrocarbons (6 microg cm(-2)), terpenes (3 microg cm(-2)), alkanols (1 microg cm(-2)), ketones (1 microg cm(-2)), alkanoic acids (1 microg cm(-2)), alkanals (0.7 microg cm(-2)), and sterols (0.6 microg cm(-2)). The concentration of the soluble cuticular components reached a peak (43 microg cm(-2)) on the 83rd day after bud break. Different causes were proposed to explicate the seasonal evolution of the leaf waxes: biosynthesis of the waxes prevalently during rapid leaf growth; natural wax erosion and evaporation; progressive reduction in the extractability of the intracuticular free compounds due to the slow polymerization of the cutin matrix.

Actinidia↗

Review of sorption and diffusion of lipophilic molecules in cuticular waxes and the effects of accelerators on solute mobilities.

Many agrochemicals are applied to the leaf surfaces of crop plants. Systemic chemicals have to penetrate through the cuticle, which forms an effective transport barrier. The barrier properties of cuticles are mainly due to the cuticular waxes deposited as partially crystalline aggregates on the outer surfaces of leaves. Substances increasing the mobilities of agrochemicals in cuticular waxes are called accelerators and it is shown that they act as plasticizers when absorbed by cuticular waxes. They decrease the barrier properties of the waxes and thus increase the mobilities of the agrochemicals through them. In order to analyse the efficiency of different accelerators, the sorption and mobility of both agrochemicals and accelerators within cuticular waxes was measured. Such information was used to establish correlations between the internal concentrations of accelerators and their mobility-enhancing effects on agrochemicals in the cuticle. This, in turn, allowed the determination and comparison of the intrinsic effects of different accelerators and to rationalize the effect of accelerators on the cuticular permeability of agrochemicals. Results describing the sorption (partition coefficients) and mobility (diffusion coefficients) of lipophilic organic molecules in reconstituted cuticular waxes from different plant species, and the effect of two different classes of accelerators (alcohol ethoxylates and n-alkyl esters), on the mobility of organic molecules are presented and discussed.

Agrochemicals↗

Effect of leaf surface waxes on leaf colonization by Pantoea agglomerans and Clavibacter michiganensis.

To evaluate the influence of leaf cuticular waxes on bacterial colonization of leaves, bacterial colonization patterns were examined on four glossy maize (Zea mays L.) mutants that were altered in their cuticular wax biosynthesis. Mutant gl3 was indistinguishable from the wild-type maize in its ability to foster colonization by the two bacterial species, Pantoea agglomerans and Clavibacter michiganensis subsp. nebraskensis. In contrast, the other three mutants supported the development of populations that significantly differed in size from those on the wild type. Mutant gl5 gl20 supported smaller populations of P. agglomerans, but not C. michiganensis, while mutant gl1 supported larger populations of C. michiganensis but not P. agglomerans. Mutant gl4 supported larger populations of both bacterial species. The exceptional ability of mutant gl4 to support bacterial colonization was hypothesized to result from the lower density of the crystalline waxes on gl4 than on the wild type, because a reduced crystal density could promote capillary water movement and water trapping among the wax crystals. This hypothesis was supported by the demonstration that the mechanical introduction of gaps among the wax crystals of the wild-type leaves resulted in the establishment of larger P. agglomerans populations on the altered leaves. These results provide the first direct evidence that leaf surface waxes affect bacterial leaf colonization at various stages of colonization and in a bacterial species-dependent manner.

Actinomycetales↗