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Epidermal and dermal phospholipids of the human eyelid: a 31P nuclear magnetic resonance spectroscopy study (1998)

Greiner, Jack V. ; Glonek, Thomas ; Townsend, Daniel J. ; [et al.]

Springer

Archives of dermatological research 290 (1998), S. 298-305

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ISSN: 1432-069X

Keywords: Key words Dermis ; Epidermis ; Eyelid ; Phospholipids ; 31P NMR

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Abstract The phospholipids of the skin are difficult to quantify because they represent only a small fraction of the skin tissue. In this study, 31P nuclear magnetic resonance, which permits precise profiling of these phospholipids, was used to compare the phospholipids of upper eyelid epidermal and dermal lipid extracts (n = 13 profiles). Phospholipid profiles included alkylacylphosphatidylcholine (AAPC), dihydrosphingomyelin (DHSM), diphosphatidylglycerol (cardiolipin), ethanolamine plasmalogen (EPLAS), lysophosphatidylcholine, phosphatidic acid, phosphatidylcholine (PC), phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, sphingomyelin, and uncharacterized phospholipids (U1 and U2, particularly enriched in the epidermis). The computed phospholipid metabolic index (n = 86 indexes) findings can be summarized as follows: a lower content of the en-ol and ether phospholipids in the epidermis relative to the dermis, internal compensation among the component phospholipids so as to maintain the choline functional group ratio, and a greater concentration of hydroxyl-containing functional groups in the epidermis. A membrane index (fmem) value of –0.37 for the epidermis deviated considerably from the value of –0.06 characteristic of living membranes and the dermis. The production of the reduced phosphatides, EPLAS and AAPC, indicates the use of alternative pathways between the two tissues. Relative to the dermis, increased PC in the epidermis coupled with decreased DHSM, EPLAS, and AAPC are factors enabling the epidermis of eyelid tissue to be an effective water barrier.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004030050308

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Structural changes in myosin during contraction and the state of ATP in the intact frog muscle (1975)

Bárány, Michael ; Bárány, Kate ; Burt, C. Tyler ; [et al.]

New York, N.Y. : Wiley-Blackwell

Journal of Supramolecular Structure 3 (1975), S. 125-140

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ISSN: 0091-7419

Keywords: Life Sciences ; Molecular Cell Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Chemistry and Pharmacology , Medicine

Notes: The reactivity of myosin to [14C]-labeled N-ethylmaleimide ([14C] NEM) or to tritium was determined in functionally different frog muscles. The incorporation of [14C] NEM into myosin decreased during isotonic or isometric contractions, as compared to resting muscle. The cysteine residues which were protected during contraction were not involved in the ATPase activity or the actin-binding ability of myosin. Peptide mapping revealed that several residues were protected simultaneously. The incorporation of tritium into the peptide N-H groups of myosin was also decreased during muscle activity. These data support the idea that activation and subsequent contraction of muscle are correlated with structural changes in the myosin molecule.The reactivity of myosin to [14C] NEM was increased when the muscle was stretched to 140% rest length and treated with iodoacetate to deplete ATP. Based on in vitro experiments and on literature data, it is suggested that in the resting muscle myosin contains bound MgATP which decreases the rate of incorporation of [14C] NEM into myosin and that upon the irreversible loss of ATP the rate increases.31P nuclear magnetic resonance signals from a number of phosphates were detected in the intact frog muscle. The data indicated that the minimum concentration of ATP in the muscle is 3 mM, a value which agrees with that of chemical determination. The characteristic chemical shifts, coupling constants, and line widths of ATP in the muscle were considerably altered from that of either free ATP in aqueous solutions or ATP in perchloric acid extracts of muscle.

Additional Material: 9 Ill.