More specific studies are recommended to examine this

suggestion. Acknowledgment The authors would like to thank the Director General of AECS, and the head of the Molecular Biology and Biotechnology Department for their support. The authors would also like to thank Dr. M. Safi for his critical reading of this manuscript. Conflict of Interest: None declared
In 1988, the Centers for Disease Control and Prevention (CDC) published two articles on nosocomial infections (NIs) and certain types of NIs’ criteria for surveillance purposes. Nosocomial infections Inhibitors,research,lifescience,medical refer to any systemic or localized conditions that result from the reaction by an infectious agent or toxin.1 The infection Inhibitors,research,lifescience,medical is developing in all high, middle and low income countries. The CDC estimated that the cost of selleckbio events related to NIs was an average of $2,100, and varied from $680 for urinary tract infections to $5,683 for respiratory tract infections in the United States of America.2 An intensive care unit (ICU) is one of the hospital wards critical in the treatment of many serious diseases, which needs particular Inhibitors,research,lifescience,medical cares. Despite having a prominent role in the care of patients with infections, ICUs cause some complications and death, and increases

the costs imposed on patients and society.3 The incidence of NIs related to mechanical ventilation, catheter insertion and some invasive procedures are more than that in other hospital wards, which do not carry such Inhibitors,research,lifescience,medical procedures.4 Classification of NIs is critical for any surveillance program. Traditionally, a time cut-off of

48 hours after admission is used to differentiate between hospital and research use community acquired infections. However such a cut-off point does not present the patients’ carrier status that can cause the infection. In an attempt to solve the problem, a classification Inhibitors,research,lifescience,medical based on pathogenesis of infection and the criteria for carrier status were offered.5 Three types of infections in ICUs including primary and secondary endogenous, and exogenous infections are defined by carrier status. Only, secondary endogenous and exogenous infections are AV-951 real infections acquired in ICUs.6 The overall incidence of NIs is 6.1% to 29.6% in pediatric ICUs. Using the CDC definition of NIs, which is defined as infection occurring 48 hours after admission, it was shown that in a sample of 1239 pediatric patients in 2009 the incidence of NIs was 24.5 per 1000 person days, and that the length of stay of patients with NI in ICU was higher than that without the infection.7 Overall, many studies have focused on the epidemiology, risk factors, and prevention methods in adults patients. However, there have been limited studies on NI in pediatric patients.

It is likely that the slow release may be caused by its poor solubility in PBS, compared to cytochrome c. The release of insulin was next examined at pH 3, because insulin is easily soluble in acidic

solution, which is a condition of the association. However, the release at pH 3 was slower than that at pH 7.4 and was perhaps affected Inhibitors,research,lifescience,medical by the charge of insulin. Insulin has an isoelectric point (pI) of 5.3 so is positively charged at pH 3 and negatively at pH 7.4. Hydroxyapatite is mostly negative, so cationic insulin might be more interactive with HA. A decrease in insulin release was observed, especially at pH 7.4 after more than 5h. The readsorption of the released insulin to HA might have occurred, because the desorption conditions differed from the Ganetespib molecular weight absorption condition. Figure 4 Time-dependent dissociation of Inhibitors,research,lifescience,medical insulin from HA (10mg) at

pH 7.4 (solid symbols) and pH 3.0 (open symbols). Our results suggest that the SKLB1002 association and dissociation properties Inhibitors,research,lifescience,medical to HA were affected by both the charge and size of proteins. HA has a hexagonal structure, in which the C (Ca-rich) site is arranged in the a–c and b–c planes and the P (Ca-deficient) site is in the a–b plane. It was reported that anionic molecules bind to the C site and cationic ones to the P site [8]. Therefore, HA-based protein delivery is Inhibitors,research,lifescience,medical suitable for pH-dependent controlled release. Cationic cytochrome c and anionic insulin at the physiological pH were absorbed and desorbed in different manners. Because the charge of insulin was changed with decreasing pH, it markedly influenced the adsorption and desorption behaviors. The absorption behavior may be very complex, because large protein molecules bind to HA at multiple points. Therefore, the regulation of controlled release of protein Inhibitors,research,lifescience,medical is still to be investigated (For further information, see Supplementary Material available online at doi:10.1155/2012/932461.). 4. Conclusions In conclusion, we prepared protein-associated HA and characterized its association

and dissociation properties. Cytochrome c and insulin could bind to and release from HA. However, their association and dissociation behaviors differed, Anacetrapib depending on the size and charge of the proteins. Therefore, HA is a potential carrier for protein delivery systems. Supplementary Material Hydroxyapatite (HA) has been studied as a biomaterial. We attempted HA to apply to delivery systems of bioactive proteins, such as cytochrome c and insulin. The association and dissociation properties of these proteins to HA were influenced by the size, solubility and net charge of protein. HA is a potential protein carrier with controlled release. Click here for additional data file.