vitamins

 vitamins primary objective was to test the non-inferiority of the 5-FU CVC compared with the CH-SS CVC in preventing catheter tip colonization (CTC), defined as the growth of 15 CFU on CVC tips prepared by the standard roll-plate method. The sample size was based on the estimation that 395 patients would be required per treatment group in order to detect, with 90% power, a significant difference in the rates of colonization between the two types of catheters at a one-tailed significance level of 5%, as is standard for non-inferiority analyses. Based on supportive evidence from the medical literature (Rijnders et al., 2002; Ramritu et al., 2008), CTC was used in this study as a surrogate end point for catheter-related bloodstream infection (CRBSI). Secondary objectives were to test the non-inferiority of the 5-FU CVC compared with the CH-SS CVC for the prevention of CRBSI, defined as growth of the same species with an identical antibiogram or ribotype isolated from a contemporaneously collected catheter tip (≥15 CFU) and percutaneously drawn blood cultures. The safety objectives for this study were to compare these devices with respect to multiple outcomes: adverse events, vital signs, physical examinations, and specific complications including: catheter occlusion, venous thrombosis, phlebitis, vessel wall injury/erosion, and allergic reactions.

Silver, in ionic or nanocrystalline form, has for many years been used as an antimicrobial agent particularly in the treatment of burns (silver sulfadiazine cream). Iodine also has the ability to lower the microbial activity in chronic wounds in two forms: (a) as povidone-iodine (polyvinylpyrrolidone-iodine complex), an iodophor; and (b) as cadexomer iodine (a three-dimensional starch lattice containing 0.9% iodine). Some of the examples of antimicrobial dressings are Acticoat, Actisorb Silver 200, Aquacel Ag, Arglaes, Avance, Inadine, Iodoflex, Iodosorb and Metrotop Gel.14 Nowadays many medicinal plants and chemicals such as aloe vera and curcumin are incorporated into the dressings to provide an antimicrobial nature to them.

Among all the antimicrobial agents, silver (Ag) is known to have strong antimicrobial activities.97 Silver impregnated textiles are used as wound dressings for infected wounds.98 Antimicrobial yarns99 can be produced from cotton, silk, polyester, nylon and their blends. The nanosilver particles showed effective antimicrobial activity against various bacteria, fungi, etc. The mechanism of antimicrobial action of silver is widely known. It enters the wound and becomes absorbed by bacteria and fungi. There it interacts with enzymes and proteins important for respiration and transport of important substances across the cell membrane. It also interacts with the DNA of bacteria, thereby inhibiting cell division. They are bound to the cell wall and outer cell, thereby changing or inhibiting the functionality of the cell membrane. In this way, it kills microbes, resulting in treatment of infected wounds.100,101 Historically, a number of polymer-based materials have been fabricated into electrospun fibers containing nAg like polyacrylonitrile (PAN),102,103 cellulose acetate (CA),104,105 poly(N-vinylpyrrolidone) (PVP)106 and poly(vinyl alcohol) (PVA).100,106,107

A novel wound dressing material was prepared by electrospinning polyvinyl alcohol and silver nitrate aqueous solution into non-woven webs and then treating these non-woven webs by heat or UV radiation. It was found that both treatments reduced the Ag+ ions in the electrospun web into Ag nanoparticles. Also, heat treatment improved the mechanical properties and thus these electrospun fiber web was an effective wound dressing.100 Some of these nAg-loaded e-spun fiber mats were tested for their antibacterial activity against E. coli, K. pneumoniae, P. aeruginosa and S. aureus.100,105,106,107 In one of the studies, mats of gelatin fibers containing nAg were prepared by e-spinning and these are used as wound dressing pads.109 Ag+ ions were reduced directly into nAg through a series of steps, including nuclei formation, crystal growth via diffusion mechanism to give primary particles, and spontaneous self-organization of primary particles to form clusters.110 The cumulative release of Ag+ ions from the samples in the acetate buffer and distilled water occurred rather rapidly during the first 60 min after submersion in the releasing medium, and increased gradually afterwards; while those in SBF occurred more gradually over the testing period, as shown in Fig. 9.17.