Shed Skin Research Articles

Dermatophagia or dermatodaxia?

To the Editor: We believe that the term dermatophagia, when used to describe compulsive biting of the skin,1Scott Jr., M.J. Scott 3rd, M.J. Dermatophagia: “wolf-biter.”.Cutis. 1997; 59: 19-20PubMed Google Scholar, 2Al Hawsawi K. Al Aboud K. Ramesh V. Dermatophagia simulating callosities.Dermatol Psychosom. 2003; 4 (Available at:) (Accessed August 20, 2004): 42-43http://content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowPDF&ProduktNr=224228&Ausgabe=229178&ArtikelNr=70535&filename=70535.pdfCrossref Scopus (8) Google Scholar gives the false impression that pieces of skin are actually ingested, rather than simply bitten or gnawed on. Accordingly, we propose a more accurate term, “dermatodaxia,” to denote habitual biting—without consumption—of the skin. Dermatophagia (Greek δερματoϕαγıα) derives from derma (δε´ρμα, “skin”) and phago (ϕα´γω, “I eat”). The word denotes the eating of skin, irrespective of whether or not one bites it. Conversely, published reports of dermatophagia describe patients whose behavior consists solely of compulsive biting or gnawing their skin, but not actually ingesting it. Indeed, these patients developed a reactive thickening of the skin, not a wound, ulceration, or loss of skin. The term “dermatophagy” is, however, used correctly by herpetologists to describe the curious instinctive behavior of some reptiles and amphibians to eat their own shed skins.3Weldon P.J. Demeter B.J. Rosscoe R. A survey of shed skin-eating (dermatophagy) in amphibians and reptiles.J Herpetol. 1993; 27: 219-228Crossref Google Scholar If dermatophagia denotes the actual consumption of skin (usually, but not necessarily, one's own), what then should we call the habit of simply biting one's skin? Autophagy won't work; it implies eating one's own tissues (observed most often among stressed laboratory rats). Autophagy also refers to lysosomal degradation of a cell's own organelles.4Kalimo H. Savontaus M.L. Lang H. Paljarvi L. Sonninen V. Dean P.B. et al.X-linked myopathy with excessive autophagy: a new hereditary muscle disease.Ann Neurol. 1988; 23: 258-265Crossref PubMed Scopus (98) Google Scholar Cheek-biting describes the simple act of biting one's own buccal mucosa; a particularly vigorous form of cheek-biting in which pieces are torn from the mucosa is called morsicatio buccarum.5Obermayer M.E. Cheekbiting (morsicatio buccarum).Arch Dermatol. 1964; 90: 185-190Crossref PubMed Scopus (18) Google Scholar After consulting dictionaries of ancient and modern Greek and consulting several scholars of the language, we would like to propose the term “dermatodaxia” for the habit of biting or gnawing on one's own skin. It is appropriate to retain dermato-, the combining form of δε´ρμα, with the suffix -ato- to achieve “of the skin”. The addition of the Greek word daxia (-δηξıα), meaning “the act of biting,” gives us “dermatodaxia.”

Excretion of three heavy metals in the shed skin of exposed corn snakes ( Elaphe guttata)

Three heavy metals of regional environmental concern—lead, cadmium, and mercury—are frequently evaluated as part of wildlife bioaccumulation and health monitoring studies. Shed skins of snakes may represent a useful, nonlethal biomarker tissue for such determinations. In the present study, these three heavy metals were injected into thawed mice that were fed to corn snakes ( Elaphe guttata) such that snakes received 2 mg/kg of each metal/month. Shed skins were collected over a period of 34 weeks, and levels of the heavy metals were determined in skins by atomic absorption methods. Each heavy metal was readily detected in the shed skins, with mean levels as follows: lead 234 ppb, cadmium 806 ppb, and mercury 403 ppb. Control snakes that were fed nonmetal-injected mice produced shed skins that contained mean levels of 6, 12, and 20 ppb lead, cadmium, and mercury, respectively. These detection levels corresponded closely to expected trace metal contents of mouse chow and tap water. These results demonstrate that dietary metal exposure can be readily detected in shed snake skins, including at trace levels of exposure that may be consistent with, or below, environmental exposures.

Organochlorine detection in the shed skins of snakes

Lizards and snakes eliminate heavy metals in their shed skins. There are no data with regard to reptilian skin as a depuration route for organochlorine (OC) compounds; however, birds deposit OCs in feathers. Corn snakes (Elaphe guttata) were therefore fed thawed mice that had been injected with a mixture of α-chlordane, Aroclor 1254 (a polychlorinated biphenyl (PCB) mixture), and lindane (γ-hexachlorocyclohexane) at 2, 8, and 4mg/kg, respectively. Feeding of contaminated mice occurred on the first weekly feeding of each month, with remaining weekly feedings consisting of noncontaminated mice, and was continued for 6 months. Shed skins were evaluated in a multiresidue OC scan by gas chromatography. All three chemical contaminants were readily detected in the shed skins: chlordane, 0.155–0.213ppm; PCB, 3.49–7.01ppm; lindane: 0.028–0.042ppm. These data suggest that the shed skin of snakes may serve as an elimination route for OC contaminants and as such may have utility as a noninvasive, nondestructive indicator tissue for assessing environmental contamination.

The First Shed Skin of Neonate Corn Snakes Is Chemically Different from Adult Shed Skins

The first shed skins from the same clutch of neonate Corn Snakes (Elaphe gutatta gutatta) and the shed skin of conspecific adults were extracted sequentially with hexane, dichloromethane, and methanol. These solvents extracted more mass from neonate shed skins compared to adults. Gas chromatography of the hexane extract, after saponification of the lipids, showed that the percent of cholesterol was greater in shed skins from neonates, whereas many of the fatty acids were found in greater amounts from adults shed skins. These data show that the first shed skin of Corn Snakes is biochemically different from adults.

Induction of micronucleated cells in the shed skin of salamanders (Ambystoma sp.) treated with colchicine or cyclophosphamide

The micronucleus (MN) assay can be used to detect the genotoxic effects of chemical agents in virtually any cell that divides frequently. Salamanders (Ambystoma sp.) are amphibians that can be easily maintained and bred in the laboratory and spontaneously shed their skin every 2.5-4 days. In this present study, we have evaluated the usefulness of this shed skin for the MN assay. We exposed salamanders to different concentrations of both the aneugen colchicine (COL) and the clastogen cyclophosphamide (CP) and we determined the frequency of micronucleated cells (MNCs) in their sheds. Fragments of shed skin were placed on clean slides, fixed, stained, observed with a light microscope, and the number of MNCs was counted. The MNC frequency was increased significantly by all doses of COL and CP tested, administered either as single or repeated exposures. The presence of MNCs in the shed skin and the speed of sloughing lead us to propose that the sheds of Ambystoma sp., or other amphibians that slough their skin, are suitable alternative models for detecting genotoxic exposures relevant to aquatic environments.

The proximate cue of density-dependent soldier production in a social aphid

Tuberaphis styraci is a social aphid that produces 2nd instar soldiers with morphological, behavioral and reproductive division. High aphid density was shown to induce soldier production in T. styraci, although direct cue of soldier induction associated with high density has been unknown. In order to identify the proximate environmental cue underlying the density-dependent soldier production, a series of experiments was conducted using an artificial diet rearing technique. When adult aphids were reared with live normal nymphs, live soldiers, dead normal nymphs, shed skins, honeydew globules and excreted wax, only live normal nymphs effectively induced soldier production. In order to gain insights into the nature of soldier-inducing cue associated with normal aphids, we performed artificial diet experiments using partitioned and non-partitioned chambers, in which direct contact between aphids was either inhibited or allowed. Induction of soldiers was observed only when direct contact was allowed. Therefore, it was shown that the soldier-inducing cue is neither volatile in the air nor diffusible through the diet, but is transmitted between normal non-soldier aphids via direct contact. On the basis of these results, we suggest that the soldier-inducing cue might be physical stimulus combined with non-volatile surface chemicals whose properties differ between normal aphids and soldiers.

Abstracts of Recent Cochrane Wounds Group Reviews

The European DNA profiling group (EDNAP) organized a sixth collaborative exercise on RNA/DNA co-analysis for body fluid/tissue identification and STR profiling. The task was to identify skin samples/contact traces using specific RNA biomarkers and test three housekeeping genes for their suitability as reference genes. Eight stains, a skin RNA dilution series and, optionally, bona fide or mock casework samples of human or non-human origin were analyzed by 22 participating laboratories using RNA extraction or RNA/DNA co-extraction methods. Two sets of previously described skin-specific markers were used: skin1 pentaplex (LCE1C, LCE1D, LCE2D, IL1F7 and CCL27) and skin2 triplex (LOR, KRT9 and CDSN) in conjunction with a housekeeping gene, HKG, triplex (B2M, UBC and UCE). The laboratories used different chemistries and instrumentation. All laboratories were able to successfully isolate and detect mRNA in contact traces (e.g., human skin, palm-, hand- and fingerprints, clothing, car interiors, computer accessories and electronic devices). The simultaneous extraction of RNA and DNA provides an opportunity for positive identification of the tissue source of origin by mRNA profiling as well as a simultaneous identification of the body fluid donor by STR profiling. The skin markers LCE1C and LOR and the housekeeping gene marker B2M were detected in the majority of contact traces. Detection of the other markers was inconsistent, possibly due to the low amounts and/or poor quality of the genetic material present in shed skin cells. The results of this and the previous collaborative RNA exercises support RNA profiling as a reliable body fluid/tissue identification method that can easily be combined with current STR typing technology.

Life in Shade: The Ecology of Anolis trachyderma (Squamata: Polychrotidae) in Amazonian Ecuador and Brazil, with Comparisons to Ecologically Similar Anoles

Abstract The Amazonian lizard Anolis trachyderma was studied at three sites stretching from eastern Ecuador to the central Amazon of Brazil. These lizards occupy low vegetation and leaf litter microhabitats in well-shaded, damp rain forest. Their body temperatures are low (27.8 C on average) and only slightly higher than corresponding substrate and air. They are as likely to be active on cloudy as on sunny days but are usually found in shade. The diet is varied, but dominated volumetrically by grasshoppers-crickets, insect larvae-eggs-pupae, spiders, roaches, and lizard shed skin. Although dietary overlaps among populations are low, no significant differences in prey choice existed based on a randomization analysis. Locality-based and sexual variation in morphology was evident. Overall, A. trachyderma appears similar ecologically across a large portion of the Amazon. Comparisons with three ecologically similar anoles, Anolis nitens scypheus (sympatric with A. trachyderma) and Anolis humilis (no range over...

Effect of aestivation on muscle characteristics and locomotor performance in the green-striped burrowing frog, Cyclorana alboguttata.

The Green-striped burrowing frog, Cyclorana alboguttata survives extended drought periods by burrowing underground and aestivating. These frogs remain immobile within cocoons of shed skin and mucus during aestivation and emerge from their burrows upon heavy rains to feed and reproduce. Extended periods of immobilisation in mammals typically result in muscle atrophy and a decrease in muscle performance. We examined the effect of aestivation and hence prolonged immobilisation, on skeletal muscle mass, in vitro muscle performance, and locomotor performance in C. alboguttata. Frogs were aestivated in soil for 3 months and were compared with control animals that remained active, were fed, and had a continual supply of water. Compared to the controls, the wet mass of the gastrocnemius, sartorius, gracilus major, semimembranosus, peroneus, extensor cruris, tibialis posticus and tibialis anticus longus of aestivators remained unchanged indicating no muscle atrophy. The in-vitro performance characteristics of the gastrocnemius muscle were maintained and burst swimming speed was unaffected, requiring no recovery from the extended period of immobilisation associated with aestivation. This preservation of muscle size, contractile condition and locomotor performance through aestivation enables C. alboguttata to compress their life history into unpredictable windows of opportunity, whenever heavy rains occur.

X-Men, and: Quotients, and: Hypnosis, and: Frank Lloyd Wright & the Last Famished Mosasaur, and: Astronomy 101, and: Road Trip

X-MEN/Nicholas Allen Harp Today in the School for Gifted Youngsters Xavier's lesson plan calls for sex education, the hows and whos, wheres and whens dispensed delicately, his bald brow furrowed serious, his students wide-eyed, chuckling, unabashedly alive and constantly, at risk from you-name-it: G-men, invasive telepathy, Plutonian radiation, slack-jawed villains, and now, he can't believe it, gonorrhea, pregnancy, AIDS, each contemporary malady less innocent than the one before, a curriculum chock-full of acronymic woe and code—IUD, HIV, RU-48f3—too many physical choices in the modern world, Xavier thinks, too many forces stitching lifeforce inextricably to doomed youth, their piss and vinegar mutated into glowy juice, concussion orbs, optic blasts, blizzards summoned by sheer merge of will, their bodies already breaking out from under themselves, pushing and yanking their skins like the colleague they call Fantastic, their young lives catapulted into flight (literally, he thinks,flight) to some fate he cannot, despite his infamous prescience, predict, a factored variable he'll have to follow, patiently, like a serial; the X of a xenophobic country, lonesome Xmases, ? ratings, the x's and o's he'll send his students when he expels them to the dangerous world. The Missouri Review · 117 QUOTIENTS/Nicholas Allen Harp Nothing less than an oriole capering and vanished in the blur screen of windshield, nothing less than the shed skin fuzz of dust atop the toaster. In Baltimore, a well-meaning scientist attempts to mass a human body as it dies, calculate the weight of the soul to fifteen significant digits as it departs wherever it is we are. An ancient iceberg bigger than Rhode Island divorces itself from Antarctica without even warning anybody, puddles meekly into the South Seas. Decimal places spool across Helsinki, Tokyo, the bedlam of Wall Street, like lemons on a slot machine, but nothing is lost. Etherized clouds of reruns lope lightspeed past stars no one's named yet, a lawyer friend in Chicago laments the French she's forgotten and Tm straining myself for that word that almost means "desire" but less gluttonous, less sad. Really nothing less than the breath of air, the gone voice that loved you, nothing less than any of us marching, shapeless, into the sky that is sometimes called empty, sometimes just called the night sky. 118 · The Missouri Review HYPNOSIS/Nicholas Allen Harp Cut a raw corncob in half with one swift chuffing motion. For a setting, choose Philomath, Georgia, and place the sun way down low, a plum turning in for the night. Note how the colors of twilight bloom like a bruise. Play Bach, poorly, in the background with only two fingers on a rickety Wurlitzer. Breathe easy. Appreciate the crows barking along the fence line, fanning across the gloppy brook in rhythm. Lose the mustache. Believe in the necessity of penmanship. Long, desperately, for the unattainable. Admire the long, loopy strokes of the founding fathers, their words etched on the mustard parchments of history. Remember the soft, worn hills of your grandfather's ears. In the future, when you want to eat a doughnut, you will immediately feel a strong urge to vomit. Search yourself for the reason you never tried out for football. Consider hurting someone you care about. Kneel to smell the patient, horologic earth, breathe in its chamomile odor. Discount any disparity between the love you give and the love you're given. Expect the gravid air to loosen its humid sag. Believe that the night will loosen you, too. The Missouri Review · 119 FRANK LLOYD WRIGHT & THE LAST FAMISHED MOSASAUR/Nicholas Allen Harp "Asfalls Wichita, sofalls Wichita Falls."—Pat Metheny In the moss-green ocean of late Cretaceous Kansas lives the last famished mosasaur, his sinuous tail undulating toward dwindled pockets of fish, orange bus-body keeping close to the shallows of proto-Wichita, pea-brained but mindful of the sharper Ginsu shark, whose fist-sized knifeslick teeth predate the cans they could cut through. Mosasaur will die shortly, peckish and chomped on, and fix like a footprint into the quick-drying sixty-eight-million-year-old Western Interior Sea. Somewhat later, in 1915 A.D., Frank...

Nondestructive indices of trace element exposure in squamate reptiles

Compared with birds, mammals, fish, and even amphibians, very little is known about the effects of contaminants on reptiles. Recent evidence that many reptile populations may be declining has stimulated demand for toxicological studies of reptiles as well as development of nondestructive sampling techniques useful for assessing and monitoring contaminant exposure. The current study experimentally evaluated the utility of shed skins, tail clips, and blood samples as nondestructive indices of trace element exposure in banded water snakes, Nerodia fasciata. For 13.5 months, snakes were either fed fish from a coal ash-contaminated site or uncontaminated food from a reference site. Snakes fed contaminated prey accumulated As, Cd, Se, Sr, and V in various organs (i.e. liver, kidney, and/or gonads). Moreover, non-parametric discriminant function analysis revealed that snakes could be placed in two groups that reliably reflected their experimental diet based upon Se, Sr, and As concentrations in tail clips, blood, and/or shed skins. We suggest that nondestructive sampling techniques, particularly analyses of blood and tail clips, may be easily applied in evaluations of contaminant exposure in the field and laboratory and may prevent excessive destructive sampling of potentially threatened reptile species.

Environmental allergen avoidance: An overview

Environmental allergen avoidance: An overview

Experimental transmission of cutaneous chytridiomycosis in dendrobatid frogs.

In a series of three experiments during March-October, 1998, two species of captive-bred poison dart frogs (Dendrobates tinctorius and D. auratus) were exposed to Batrachochytrium dendrobatidis, a recently-described chytridiomycete fungus (chytrid) that was originally isolated from a blue poison dart frog (D. azureus). All frogs exposed to the chytrids developed a fatal skin disease, whereas none of the control frogs developed skin lesions. The most consistent clinical sign in chytrid-exposed frogs was excessive shedding of skin. Gross lesions were subtle, usually affected the legs and ventrum, and consisted of mild skin thickening and discoloration. Microscopic examination of shed skin pieces and/or skin imprints demonstrated the presence of chytrids and was used for ante mortem and post mortem confirmation of chytrid infection. Histologically, there was epidermal hyperkeratosis, hyperplasia, and hypertrophy associated with low to moderate numbers of chytrids in the keratinized layers. These experiments demonstrated that Batrachochytrium dendrobatidis can be a fatal pathogen in poison dart frogs. The experimentally-induced disease in these frogs resembled cases of cutaneous chytridiomycosis that have recently been described in several other species of captive and wild amphibians.

A Comparison of Organic Solvent Extracts and the Fatty Acid Composition of Nonpolar Lipids of Shed Skins from Male and Female Corn Snakes (Elaphe guttata guttata)

In order to characterize the differences in chemical composition between male and female integument, shed skins of corn snakes (Elaphe guttata guttata) were sequentially extracted with hexane, dichloromethane, and methanol. Nonpolar (hexane) and polar (methanol) organic solvents extracted greater mass from male than female shed skins. A comparative analysis of the fatty acid composition of hexane extracts indicated no significant sexual differences in the chemical composition of nonpolar lipids found in the shed skins. Within the detection limits of this analysis, it is unlikely that corn snakes use nonpolar lipids for sex identification during the non-breeding season, because the fatty acid composition of the

In vitro permeation of progesterone from a gel through the shed skin of three different snake species

The in vitro diffusion of progesterone from a gel formulation using the European Pharmacopoeia method for transdermal dosage forms is described. The membranes used were the dorsal and ventral portions of the shed skin of three different species of snake. Considerable differences are apparent between the dorsal and ventral sites and between the different species of snake. The dorsal area shows better permeability for progesterone and the permeability order for the different species is python>cobra>viper. These differences may be due to the thickness of the skin and the hinge:scale ratio. The results indicate that shed snake skin is not a model membrane for human skin.

Treating swimmer's ear

Fungi cause some of the vilest and most recalcitrant of all human infections. They also give rise to a wide range of less dramatic conditions that are virtually untreatable—either because appropriate drugs do not exist or because antifungal agents cannot be delivered on site in the requisite concentration. One such is otomycosis, a form of external otitis caused by fungi growing on shed skin in the ear canal. Preparations are available to treat the condition, but they have serious limitations. Now, from the University of New Mexico in Albuquerque, comes news of …

Altruistic housekeeping in a social aphid

Aoki (1977) discovered that some aphids have a sterile soldier caste, which functions altruistically to protect the colony from predators. For the first time we show experimentally that the soldier caste of an aphid, the gall-forming Pemphigus spyrothecae, fulfils a second, non-defensive, altruistic role: the soldiers actively clean their gall. This `housekeeping9 behaviour, in which defecated honeydew, shed skins and dead aphids are removed from the gall, is costly to the soldiers and essential for gall survival. The colony9s waste is actively manipulated to the entrance of the gall by the soldiers and pushed out. Different techniques of manipulation are used for objects of different type and size. This species, and perhaps many aphid species, have a complex repertoire of altruistic behaviours involving housekeeping and defence, which suggests a social system approaching that of the major groups of eusocial insects.

Responses by corn snakes (Elaphe guttata) to chemicals from heterospecific snakes

Young corn snakes,Elaphe guttata, were tested for responses to chemicals from heterospecific snakes. Corn snakes exhibited more tongue-flicks to swabs freshly rubbed against the skin of an ophiophagous kingsnake,Lampropeltis getulus, than to blank swabs. Responses toL. getulus and a nonophiophagous western plains garter snake,Thamnophis radix haydeni, did not differ significantly. Corn snakes exhibited more tongue-flicks to swabs treated with chloroform extracts of the shed skins ofL. getulus; an ophiophagous eastern coachwhip,Masticophis flagellum; and a nonophiophagous gray ratsnake,Elaphe obsoleta, than to blank swabs, but they did not discriminate between ophiophagous and nonophiophagous species in every case. Corn snakes, when offered shelters containing bedding from the home cages of a nonophiophagous water snake,Nerodia erythrogaster, an occasionally ophiophagous water moccasin,Agkistrodon pisdvorus; orL. getulus and untreated bedding, failed to reside under snake-scented shelters at a rate significantly different from that expected by chance. The responses of corn snakes are compared with those reported for other snakes presented with heterospecific snake chemicals.

New alkyl N,N-dialkyl-substituted amino acetates as transdermal penetration enhancers.

New alcohol derivatives of N,N-disubstituted amino acids with a low toxicity have been synthesized and evaluated for their transdermal penetration enhancing effects on the transport of indomethacin from petrolatum ointments across shed skin of black rat snake (Elaphe obsoleta). The derivatives show excellent penetration enhancement of indomethacin, as high as 3.8 times that of Azone, with decyl N,N-dimethylamino acetate as the lead compound in the series. The release of indomethacin from an ointment containing 1% indomethacin, 5% dodecyl N,N-dimethylamino acetate, and 94% petrolatum was 3.15 micrograms/min1/2/cm2. Saturation studies performed by incorporating varying concentrations of indomethacin, from 0.1 to 10%, into the ointments and determination of the fluxes of indomethacin demonstrated that the saturated concentration of indomethacin in petrolatum base was approximately 1%. Penetration fluxes of indomethacin (1%) through snake skin increased linearly as the concentration of dodecyl N,N-dimethylamino acetate increased from 2.5 to 15%. Experiments involving the pretreatment of the snake skins with dodecyl N,N-dimethylamino acetate indicated that pretreatment of the skin increased the skin permeability significantly. Electron micrograph studies on the snake skin treated with dodecyl N,N-dimethylamino acetate show clearly that the enhancer interacted with both the lipid-rich layer (mesos phase) and the keratin-rich layers (both alpha and beta phases).

Lead in the scales of cobras and wall lizards from rural and urban areas of Punjab, India

The shed skins of cobras and scales of wall lizards collected from heavily pollluted urban areas are shown to contain significantly higher levels lead than tbose of the same animals from rural areas.