Skin, structure

Fig. 3-9 Thin-skinned structures with integral ribbing to carry edge loads.

Montagna W, Prota G, Kenney JA (1993) Black skin structure and function. Academic Press, San Diego, PP 42-45... 

Recognizing the presumed site of infection and most common pathogens associated with the infectious source should guide antimicrobial choice, dose, and route of administration. For example, community-acquired pneumonia is caused most commonly by S. pneumoniae, E. coli is the primary cause of uncomplicated UTIs, and staphylococci and streptococci are implicated most frequently in skin and skin-structure infections (e.g., cellulitis). 

Systemic therapy with a variety of (3-lactams, macro-lides and lincosamides (clindamycin) has been the cornerstone of skin infection therapy for many years [17]. However, topical antibiotics can play an important role in both treatment and prevention of many primary cutaneous bacterial infections commonly seen in the dermatological practice [18], Indeed, while systemic antimicrobials are needed in the complicated infections of skin and skin structure, the milder forms can be successfully treated with topical therapy alone [18], The topical agents used most often in the treatment of superficial cutaneous bacterial infections are tetracyclines, mupirocin, bacitracin, polymyxin B, and neomycin. 

Guay DR Treatment ofbacterial skin and skin structure infections. Expert Opin Pharmaco-ther 2003 4 1259-1275. 

Fig. 5.9. Schematic illustration (not to scale) of the onion-skin structure in the interior of a highly evolved massive star (25 M0). Numbers along the vertical axis show some typical values of the mass fraction, while those along the horizontal axis indicate temperatures and densities (gmcm-3). Adapted from Kippenhahn and Weigert (1990).

SSSIs - skin and skin structure infections cSSSIs - complicated skin and skin structure infections RTIs - respiratory tract infections. G+ - Gram positive. 

A number of recent publications indicate that the antibacterial field has adopted the concept of comparing free drug concentration at the site of action to in vitro drug potency reported as MIC [24-26]. A study of the antibacterial ertapenem in healthy volunteers was carried out to provide support for its use in skin and skin-structure infections [27]. Using microdialysis techniques, unbound drug concentrations in muscle and subcutaneous tissues were sampled at... 

R. C. Scott, M. A. Corrigan, F. Smith, and H. Mason. The influence of skin structure on permeability An intersite and interspecies comparison with hydrophilic penetrants. J. Invest. Dermatol. 96 921-925 (1991). 

Menon GK (2002) New insights into skin structure scratching the surface. Adv Drug Deliv Rev 54(Suppl 1 ) S3—S17. 

Topical formulations are another special case. Over time, it has been shown that the minipig has a skin structure that is quite similar to humans, and that species is now used commonly as the nonrodent model. These types of formulations also require local irritation studies where guinea pigs are used to determine delayed contact sensitization. Selection of the animal species for the nonclinical program is often not straightforward. 

Even newer is the natural product daptomycin (Cubicin), a complex cyclic lipopeptide structure, approved for use in the United States in 2003. Daptomycin has a spectrum similar to that of linezolid and specifically includes MRSA and VRE. In contrast to linezolid, daptomycin is bactericidal for these Gram-positive organisms. It is, like vancomycin, a parenteral antibiotic and is given intravenously. It is indicated for treatment of complicated skin and skin structure infections and for some cases of bacteremia, including endocarditis. Daptomycin may be thought of as an alternative to vancomycin. 

Relationship Between Nodular and Rejecting Layers. Nodular formation was conceived by Maler and Scheuerman (14) and was shown to exist in the skin structure of anisotropic cellulose acetate membranes by Schultz and Asunmaa ( ), who ion etched the skin to discover an assembly of close-packed, 188 A in diameter spheres. Resting (15) has identified this kind of micellar structure in dry cellulose ester reverse osmosis membranes, and Panar, et al. (16) has identified their existence in the polyamide derivatives. Our work has shown that nodules exist in most polymeric membranes cast into a nonsolvent bath, where gelation at the interface is caused by initial depletion of solvent, as shown in Case B, which follows restricted Inward contraction of the interfacial zone. This leads to a dispersed phase of micelles within a continuous phase (designated as "polymer-poor phase") composed of a mixture of solvents, coagulant, and a dissolved fraction of the polymer. The formation of such a skin is delineated in the scheme shown in Figure 11. 

This implies that the selective layer of reverse osmosis membranes may have a different origin from that of the micelles. Such a case is clearly identified by examination of the skin structure of cellulose acetate/poly(bromophenylene oxide phosphonate) alloy membranes (1 ), which exhibit a high flux and high salt separation (Figure 13). The skin rests on an assembly of giant spheres (up to 1 pm in diameter) and is certainly originated by a different coagulation mechanism than that of the spheres. 

Breed J, Teras J, Gardovskis J, Maritz FJ, Vaasna T, Ross DP, Gioud-Paquet M, Dartois N, Ellis-Grosse EJ, Loh E. (2005) Safety and efficacy of tigecycline in treatment of skin and skin structure infections Results of a double-blind phase 3 comparison study with vancomycin-aztreonam. Antimicrob Agents Chemother 49 4658 666. 

Noel GJ, Bush K, Bagchi P, lanus J, Strauss RS. (2008) A randomized, double-blind trial comparing ceftobiprole medocaril with vancomycin plus ceftazidime for the treatment of patients with complicated skin and skin-structure infections. Clin Infect Dis 46 647-655. 

Talbot GH, Thye D, Das A, Ge Y. (2007) Phase 2 study of ceftaroline versus standard therapy in treatment of complicated skin and skin structure infections. Antimicrob Agents Chemother 51 3612-3616. 

Fig. 7.3. Cross-section of a massive star. The onion-skin structure is specific to massive stars at the end of their existence.

Skin structure varies widely in different regions, from the delicate and relatively permeable skin of the scrotum, to the rough, thick covering of the palms and soles." The skin of the scromm has a relatively thin layer of keratin, whereas the palms and soles have a thick layer. 

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