Outer Surface Of Skin Research Articles

Nuchal fold thickness at 14-16 weeks' gestation as measured by transvaginal sonography.

To establish normal values of fetal nuchal fold thick-ness at 14-16 weeks of gestation by transvaginal sonography. Transvaginal sonography was used to measure nuchal fold thickness in 182 normal pregnancies at 14-16 weeks of gestation. Nuchal fold thickness was measured as the distance from the outer skull bone to the outer skin surface in the transverse axial image in the suboccipital-bregmatic plane of the head. There was no significant association between nuchal fold thickness and gestational age (r = 0.084; P = 0.258). The mean (standard deviation) was 2.2 (0.5) mm and the 95th centile was 3.0 mm. The 95th centile of nuchal fold thickness measured by transvaginal sonography at 14-16 weeks is 3.0 mm.

Signal generating endotracheal tube apparatus

The present invention is directed to an endotracheal apparatus for providing reliable airway management in a patient. A flexible tube extends from the patient's oral or nasal cavity to a distal end within the trachea. A first ultrasound transducer means connected to the tube near its distal end is in intimate contact with the forward inner wall of the patient's trachea at substantially its midpoint. A second ultrasound transducer means is disposed in intimate contact with the forward outer skin surface of the patient's neck. Either the first or the second transducer means can be a transmitter of an ultrasound signal provided by ultrasound transducer excitation means, to which it is electrically connected. The other transducer means serves as a receiver, which is connected to ultrasound detector means situated externally to the patient. Also in accordance with the invention, a process for monitoring the position of an endotracheal tube inserted in a patient utilizes an apparatus that comprises first transducer means disposed within the trachea of the patient and second transducer means disposed on the outer skin surface of the patient's neck.

樹脂複合型制振鋼板のスポット溶接性（第２報） 金属粒子添加による制振鋼板の導電化と溶接欠陥

In order to spot-weld VDSS without providing a shunting curcuit, electro-conductive property is needed to the core damping material. The method to give electro-conductivity is addition of metal particles into the resin which has diameter nearly equal to the resin thickness to ensure direct contacts between skin sheets.As particles were increased or resin thickness became thinner under the same particle content, the resistance between skin sheets was reduced. Nickel particle exhibited the best conductivity of all which were tested.In the case of the small amount of Nickel particle, pin-hole defects were observed and these defects were peculiar to the welding of VDSS because welding current was concentrated to an specific Nickel particle with relatively low electrical resistance. The defect was caused by growing the melting area by joule heating to the outer surface of skin sheet.Decreasing the voltage between skin sheets is effective to prevent pin-hole defect formation. From the practical point of view, it is needed that decreasing the resistance between skin sheets or controlling the welding voltage.As for the resistance, it was showed that initial resistance between skin sheets was useful for the virtual index in material production. Using a sufficient conductive VDSS, time to exclusion of resin was quite short, and weld defect was not observed.

Methods forin VivoTissue Electroporation Using Surface Electrodes

AbstractElectroporation of tissues has many potential biomedical applications, including transdermal and targeted drug delivery. Although there are established protocols for electroporation of single cells, electroporation of tissues remains largely unexplored. Here we describe methods for in vivo tissue electroporation with surface electrodes, where either (a) molecules are provided at the outer surface of skin and electroporation is caused in order to transport molecules across the skin or (b) molecules are injected into an animal and internal tissue cells are electroporated to enhance up-take of the injected molecules. Factors considered in our experimental design include selection of electrode material and electrode/tissue geometry. Electrode materials were used which could accommodate a high instantaneous current density and were expected not to form harmful electrochemical products. Due to the complex heterogeneous nature of tissues, the choice of electrical pulse parameters was guided by, but not b...

Skin penetration by ensheathed third-stage infective larvae of Negator americanus, and the host's immune response to larval antigens

Kumar S. and Pritchard D. I. 1992. Skin penetration by ensheathed third-stage infective larvae of Necator americanus, and the host's immune response to larval antigens. International Journal for Parasitology 22: 573–579. In vitro experiments were conducted to assess skin penetration by ensheathed third-stage infective larvae (L3) of Necator americanus. The fact that only a small proportion of larval sheaths was recoverable from the outer skin surface suggested that some larvae penetrate mouse skin without undergoing exsheathment. Penetration by ensheathed larvae was confirmed visually using a novel fluorescein isothiocyanate (FITC)-labelling technique in which viable ensheathed larvae were fluoresceinated, applied onto intact mouse skin, and their progress monitored in frozen skin sections. This direct observation that the L2-derived sheath can present antigens to the host's immune system was also monitored by immunoassay to provide confirmatory information regarding skin penetration by ensheathed larvae. Sera from humans infected with Necator americanus were shown to react in ELISA against antigens stripped by detergent (cetyltrimethylammonium bromide) from the sheath surface, and with antigens contained in L3-exsheathing fluid. These data suggest that the host's immune response, as a result of antigenic stimulation by the cast sheath and exsheathing fluid, could in fact be diverted away from the potentially vulnerable L3 stage.

Structural and functional response of the isolated toad skin to mucosal lithium.

Structural and functional changes induced by long-term Li-exposure of the outer surface of toad skin was studied. Electron microscopy revealed that total Na by Li replacement in the outer compartment of short-circuited toad skin promotes a conspicuous cellular damage expressed as focal swollen cells with altered intercellular spaces and nuclear morphology. Short-circuit current (SCC) decreases by about 70% over the first 60 min after 115 mmol/l Li-exposure. An amiloride sensitive transepithelial Li transport remains intact over a further 150 min despite the epithelial damage, indicating that the pathways across the apical barrier are functioning. Increase of the paracellular permeability is detected by elevation of Na-efflux. Partial 50% or 10% Na by Li replacements induce minor structural alterations and are not sufficient to trigger appreciable Na-efflux and SCC alterations. Therefore, low Li concentrations are less effective than 115 mmol/l in promoting morphofunctional responses. Although ouabain and Li reduce the SCC, ouabain does not promote structural lesions, showing that Li-inhibition of Na transport by itself is not responsible for the observed morphological alterations. In the light of this study, Li utilization as a tool to investigate transepithelial Na transport requires careful judgement.

The Lipid Secretion of the Meibomian Glands

Publisher Summary The outer surface of mammalian skin and hair is covered by the lipid secretion of the sebaceous glands; in birds, this function is fulfilled by the secretion of the large uropygeal or preen gland, sebaceous glands are numerous around all body apertures, and might be modified in form or nature of secretion to suit the special conditions of these sites. Meibomian glands are found in well-developed form in mammals. They appear to be elongated sebaceous glands, embedded in the fibrous tarsal plate of upper and lower eyelids. Meibomian secretions have much in common with sebaceous lipids, and similar analytical techniques can be used for both. Many of these are similar to the techniques that are used for analysis of a variety of other biological lipids; however, the “differentness” of sebaceous-type lipids means that additional methods must be used to cope with chain branching, wax esters of high molecular weight, a variety of unusual steryl esters, complex diesters, and other unique factors.

Sodium flux in the apical membrane of the toad skin: aspects of its regulation and the importance of the ionic strength of the outer solution upon the reversibility of amiloride inhibition.

Injection of small pulses of concentrate solutions of salts or drugs into the outer bathing fluid led to sudden increases of its solute concentration. Vigorous stirring of the outer bathing solution was used to minimize the thickness of the unstirred layer adjacent to the outer skin surface. Pulses of 1 M NaCl injected into the outer compartment induced sharp increases of the SCC following a time course variable with the magnitude of the pulse and the particular condition of each skin. Comparison of the spontaneous decline of the SCC with the decline induced by a small dose of amiloride, where an increase in R was observed, indicates that the spontaneous decline cannot be explained simply as a reduction of the Na permeability of the apical membrane by self-inhibition of feedback inhibition of the apical membrane Na channels. Reduction of the driving force for Na movement into the epithelial cells must play an important role in the process. Reversibility of the amiloride inhibition of the SCC was highly dependent upon the ionic strength of the solution used to rinse and wash out the inhibitor from the outer skin surface. With H2O, the amiloride molecules washed out slowly as compared to NaCl or KCl solutions. Na or K have the same ability to dislodge the amiloride molecules from their binding sites. This effect is apparently of a purely electrostatic nature.

Lack of PCMB action upon the outer barrier sodium permeability in the absence of Na in toad skin.

The stimulation of apical Na permeability by p-chloromercuribenzoate (PCMB) was evaluated by studying its effect on unidirectional 24Na flux (JNaeff) from inner to outer compartment in the isolated short-circuited toad skin. With Na present in the inner compartment, addition of PCMB to the outer skin surface led to an increase of JNaeff. However, after replacing all Na of the inner compartment by K or choline, the amiloride inhibitable Na permeability of the outer cell membrane increased, and PCMB was no longer effective. It is concluded that PCMB releases the blocking effect of intracellular Na on apical Na channels. If intracellular Na is drastically reduced virtually all Na channels are opened so that PCMB does no longer act.

Interrupted single sutures versus intracutaneous sutures in irregularly shaped skin lesions: A comparative animal study

In a rabbit model a comparative study on the adaptation of irregular and curved skin wounds closed by interrupted single and intracutaneous sutures was done. The clinical course and the histological result were compared. The wounds closed by intracutaneous sutures healed quicker and with less reaction. Especially, the adaptation at the angle of the angle-shaped wounds was better with the intracutaneous than with the interrupted single sutures. An explanation for this could be a more physiologic way of wound closure, the incorporation of less suture material and less suture channels communicating with the outer surface of the skin.

Cellular Li+ opens paracellular path in toad skin: Amiloride blockable effect

The presence of Li in the solution bathing the outer surface of toad skin under short-circuit condition promotes an unspecific permeability increase characterized by a delayed and progressive increase in the effluxes of 24Na, 42K and 14C sucrose. The effect of Li upon sucrose permeability might indicate an increased permeability of the paracellular pathway. The Li effect is mediated by an intracellular action since blockade of Li entrance into the cell compartment by amiloride prevents the increase in Na, K and sucrose permeability. A possible mechanism of this effect is discussed in terms of a disturbance in the cellular Ca++ balance leading to an increase in cytosolic Ca++ concentration which perturbs the organization of the cytoskeleton and the interplay between cytoskeleton and tight junctions.

Stimulus‐induced release of endogenous amino acids from the Xenopus laevis lateral‐line organ

Previously, we described a method for studying stimulus‐induced release of substances from the Xenopus lateral line [Bledsoe et al., J. Acoust. Soc. Am. Suppl. 1 65, S11(A) (1979)]. To date, 13 experiments have been completed in which the release of endogenous amino acids was studied by comparing the effects of pulsatile water motion on the efflux of glutamate and aspartate from isolated skins with and without lateral‐line stitches. For a given experiment paired stitch and nonstitch skins were subjected to two. 30‐min periods of stimulation and two, 30‐min periods of no stimulation in a rotated order‐of‐occurrence. In an overall comparison of mean amino acid levels for the first and second periods of the stimulated versus nonstimulated conditions, stimulation applied to the outer skin surface caused a significant increase in glutamate and aspartate efflux from stitch (p < 0.01) and nonstitch (p < 0.01) skins. The stimulated efflux of glutamate from stitch skins was significantly greater than the stimulated efflux from nonstitch skins (p < 0.01). For aspartate efflux the between skin comparison was less clear cut with stimulation causing a significantly greater efflux from stitch skins than from nonstitch skins (p < 0.01), only when comparing the mean aspartate levels for the first periods of the stimulated versus nonstimulated conditions. Although the source and mechanisms underlying the greater stimulated efflux from stitch skins remain to be determined, the results demonstrate differences between stitch and nonstitch skins under stimulus conditions which should induce release of the afferent transmitter substance(s). [Work supported by NIH and The Kresge Foundation.]

Microelectrode studies of the active Na transport pathway of frog skin.

When the outer surface of short-circuited frog skin was penetrated with microelectrodes, stable negative potentials that averaged near -100 mV were recorded consistently, confirming the results of Nagel (W. Nagel. 1975. Abstracts of the 5th International Biophysics Congress, Copenhagen. P-147.). The appearance of these stable potentials, V(O), concurrent with the observations that (a) a high resistance outer barrier R(O) accounting for approximately 75 percent or more of the transcellular resistance of control skins had been penetrated and that (b) 10(-5) M amiloride and reduced [Na] outside caused the values of V(O) to increase towards means value near -130 mV while the values of percent R(O) increased to more than 90 percent. It was of relationships were the same as the values of E(1) observed in studies of the current-voltage relationships were the same as the values of E'(1) defined as the values of voltage at the inner barrier when the V(O) of the outer barrier was reduced to zero by voltage clamping of the skins. Accordingly, these data are interpreted to mean that the values of E(1), approximately 130 mV, represent the E(Na) of the sodium pump at the inner barrier. 2,4-DNP was observed to decrease the values of transepithelial voltage less than E(1) the V(O) was negative. These data can be interpreted with a simple electrical equivalent circuit of the active sodium transport pathway of the frog skin that includes the idea that the outer membrane behaves as an electrical rectifier for ion transport.

Transepithelial transport kinetics and Na entry in frog skin: effects of novobiocin

Na+ entry across the outer surface of frog skin and transepithelial Na transport were studied simultaneously at different [Na] in either the presence or absence of novobiocin by direct measurements of J12 (unidirectional uptake) and Io (short-circuit current). J12 consisted of two components: one linear, the other saturable. The kinetic parameters of the saturating components in controls were close to the kinetic parameters of overall transepithelial transport (Jm12 = 1.68+/-0.13 mleq cm-2h-1; Io =1.80+/-0.14 mueq cm-2h-1. K12 = 6.02+/-1.27 mM;Kio=6.12+/-1.33 mM). Novobiocin significantly augmented net transepithelial Na transport by increasing J13. J31 remained unaffected. A 1:1 relationship between the saturating component of J12 and Io was observed in both treated and untreated skins at all [Na] tested. (Jm12Iom, k12, and Kio were significantly larger in treated skins, but despite very drastic changes in transport rates, a close correlation between kinetic parameters of entry step and transepithelial transport was maintained. This suggests that the kinetics of transepithelial transport may simply reflect those of the rate-limiting step: the Na entry across the outer barrier of the skin. The results indicate that the linear component of J12 is not involved in transepithelial transport kinetics.

Influx and efflux of sodium at the outer surface of frog skin.

The unidirectional Na influx j12, and Na efflux, j12, at the epithelial surface of the frog skin were determined under various experimental conditions. The j21 was taken as the difference between j12 and the simultaneously measured shortcircuit current (SCC). Errors in j12 determination originating from various transport rates within the skin were kept to a minimum using a normalization procedure. Under control conditions, j12 (1.20 muEquiv/cm-2. hr) was found to be only slightly larger than the SCC (1.10 MUEquiv/cm-2. hr). After inhibition of the transepithelial Na transport by amiloride, ouabain, low temperature and low Na concentration, the reduction of j12 and SCC was almost identical, indicating that the entrance of Na into the epithelium is rate limiting for the transepithelial transport. Compared to the control, j21 remained unchanged after amiloride and ouabain, but was insignificantly reduced at low temperature and significantly reduced at low Na concentration. These data are consistent with the assumption that the Na efflux follows mainly an extracellular pathway.

Speed of voltage threshold shift after step-changes of (Na)o and (Ca)o at the outer surface of frog skin.

The voltage thresholdV s of the N-shaped I–V curve of in vitro frog skin was studied with respect to its dependence on the Na- and Ca-concentration of the outer bathing solution. Step changes of (Na)0 and (Ca)0 were repeatedly produced in a fast flow chamber, and the time course of the resulting threshold change was determined stroboscopically under voltage clamp conditions. In response to an increasing step of (Na)0 (complete in 20 ms),V s increased rather slowly with a halftime of about 200 ms, while the short circuit current increased 4 times faster. This increase in short circuit current can have raised the cellular Na-concentration (Na) c by no more than 0.1 mM within 200ms. Therefore, the change ofV s -although slow—will hardly have been caused by an increase of (Na) c . We explain the change ofV s by a direct influence of (Na)0 on the apical membrane of the Str. granulosum. In response to a step increase of (Ca)0,V s decreased with a halftime of 50 ms. This fast response and the low Ca-permeability of the apical membrane again make a causal role of cellular concentration changes unlikely. Apparently, (Na)0 and (Ca)0 affectV s directly—from the outside of the membrane—and not by mediation of more time consuming changes of intracellular concentrations.

Effect of antidiuretic hormone on sodium uptake across outer surface of frog skin.

ARTICLESEffect of antidiuretic hormone on sodium uptake across outer surface of frog skinTU Biber, and LJ CruzTU Biber, and LJ CruzPublished Online:01 Oct 1973https://doi.org/10.1152/ajplegacy.1973.225.4.912MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByRegulation of apical Na+ conductive transport in epithelia by pHBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, Vol. 1241, No. 1NaCl Transport in Amphibian SkinThe role of sodium-channel density in the natriferic response of the toad urinary bladder to an antidiuretic hormoneThe Journal of Membrane Biology, Vol. 64, No. 1-2Effect of Li and of other ions on Na transport in epithelial cells of frog skinBiochemical Pharmacology, Vol. 29, No. 16Effect of external cation and anion substitutions on sodium transport in isolated frog skinThe Journal of Membrane Biology, Vol. 52, No. 2Effect of FeCl3 on ion transport in isolated frog skinThe Journal of Membrane Biology, Vol. 52, No. 2Colchicine inhibition of ADH effect on frog skin permeabilityExperientia, Vol. 34, No. 3Transport Across Amphibian SkinTransport Across Amphibian Urinary BladderIonic exchanges in isolated and open-circuited toad skinThe Journal of Membrane Biology, Vol. 35, No. 1Sodium pump stimulation by oxytocin and cyclic AMP in the isolated epithelium of the frog skinPflügers Archiv European Journal of Physiology, Vol. 371, No. 3Computer modelling. Application to studies on the initial rate of Na+ uptake by frog skin epidermisJournal of Theoretical Biology, Vol. 65, No. 4Effects of insulin on short-circuit current and Na-K-ATPase activity of the toad skin and urinary bladderComparative Biochemistry and Physiology Part A: Physiology, Vol. 58, No. 2Na-K-ATPase and transepithelial sodium transport in the toadComparative Biochemistry and Physiology Part A: Physiology, Vol. 56, No. 4Effects of Cd++ on short-circuit current across epithelial membranesThe Journal of Membrane Biology, Vol. 26, No. 1Solute transport across isolated epitheliaKidney International, Vol. 9, No. 2Structure and Function of the EpidermisLithium transport across isolated frog skin epitheliumThe Journal of Membrane Biology, Vol. 25, No. 1Effects of furosemide on sodium content and transport pool in frog skin (Rana esculenta)Naunyn-Schmiedeberg's Archives of Pharmacology, Vol. 290, No. 2-3 More from this issue > Volume 225Issue 4October 1973Pages 912-917 Copyright & PermissionsCopyright © 1973 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1973.225.4.912PubMed4542709History Published online 1 October 1973 Published in print 1 October 1973 Metrics

Sodium influx at the outer surface of frog skin

The unidirectional sodium influx across the outside surface of the frog skin epithelium was measured. The method was identical to the one described by Biber and Curran [4] except that mannitol instead of inulin was used as the indicator for the amount of tracer containing test solution remaining on the surface of the skin after blotting. The space of distribution for(3)H-mannitol is about twice as large as the corresponding space for inulin after 32-sec exposure to the tracer. At a sodium concentration of 6.7MM the sodium influx determined with inulin as marker for the test solution is 0.146 μEquiv hr(-1)cm(-2) larger than the influx measured in the same preparation with mannitol. This difference increases in proportion to the sodium concentration and can be ascribed to diffusion of sodium into a space which is accessible to mannitol but not to inulin during a 30-sec interval. Hence, nearly two-thirds of the previously described linear component of the sodium influx proceeds, as was suspected previously, into a compartment which is not directly connected to net sodium transport across the skin. The nature of the remaining one-third of this linear compartment is not clear but previous experiments suggest that it is also not involved in net sodium transport.

Simultaneous Measurement of Subglottal and Supraglottal Pressure Variations

The short-term variations of the subglottal and supraglottal pressures during phonation were measured simultaneously, utilizing two identical miniaturized solid-state pressure transducers [Y. Koike, J. Acoust. Soc. Amer. 46, 96–97 (1969)] inserted into the trachea and the pharynx through the nostrils, to obtain a direct estimation of the waveform of the pressure difference across the glottis at a close distance. The magnitudes of these short-term variations and the phase relations between them were analyzed, and their effect on the vibration of the vocal folds is investigated on the basis of a mechanical model of the laryn. Simultaneously with the above measurements, the vibration of the outer skin surface of the trachea was picked up with a 14-in.-diam condenser microphone coupled with a rubber pipe. The resulting waveform displays considerable agreement with that of the subglottal pressure, and it is shown that the contact microphone output may be applicable to the study of the detailed properties of the amplitude and phase spectrum of the subglottal pressure variation or of the glottal sound by taking into account the transmission characteristic of the tracheal wall and the acoustic impedance of the trachea. These characteristics can be calculated from the results of the above measurements. [This study was partially supported by a USPHS grant and by NASA contract.]

A Simple Method of Mounting Small Exhibit Specimens of Mammals and Birds

At regular intervals, biology teachers are confronted with the problem of presenting their work graphically to boards, patrons and laity. Biology teachers in high schools and colleges are frequently charged with the task of preparing such exhibits in order to found or expand the Museum of the Biological Department as a teaching adjunct. Because an expense acount seldom envisages the preparation of these demonstrations, professional assistance cannot be readily procured. It is for the above reasons that I believe my simple method of mounting small mammals is worth placing on record. This technique was first applied to mouse specimens exhibited at the Harvard Tercentenary in 1936, and more recently it has been employed on rats for the museum collections of the Wistar Institute, where they will be pointed out upon request. There is no reason why this method can not be readily extended with modifications to small birds and mammals generally. For the sake of simplicity I shall here describe the method as applied to the rat. First, kill the rat with a lethal dose of ether, or chloroform or by some other method that will not harm the anatomy. Inject 10 cc of 40 per cent. formaldehyde into the thoradie cavity and another 10 cc into the abdominal cavity, massaging the animal to distribute the injection fluid within the body cavities. Inject smliall amounts into the legs and subcutaneously over the body. Within 15 minutes to half an hour subsequent to this injection the body will stiffen. When fairly rigid, place the rat upon a small temporary base-block of wood in the position desired for the finished specimen. Brad the rat's tail to the block. Then brad the four feet to their proper positions bending the body into the pose desired. The hips may be prevented from moving laterally by hammering several 7-penny nails into the block adjacent to the hips. The head may be held up by resting the teeth on a block of proper dimensions. See Fig. A. When the animal is in the position desired, allow it to stand an hour or so until it has completely hardened. Invert the specimen and wash it thoroughly under a faucet so water will wet the whole outer surface of the skin. Place the inverted specimen, block and all, into a jar of formalin and allow it to stand 24 hours. The previous washing removes all air caught in the fur that might prevent areas of the skin from coming in contact with formalin. After the specimen has cured 24 hours in formalin, wash under the faucet for a few minutes to remove all traces of formalin, which will attack the skin of the operator 's hands, unless they are otherwise protected. Lay the specimen on its back, and with a sharp razor blade cut the skin along the mid-ventral line from throat to geni1 Reprinted in part from Science.