Silver Sulfadiazine and Cerium Nitrate in Ischemic Skin Necrosis of the Leg and Foot: Results of a Prospective Randomized Controlled Study

Maternal cerium nitrate exposure induces developmental immunotoxicity in BALB/c mouse offspring

With the increasing application of cerium and rare-earth elements (REEs), cerium exposure is becoming more widespread. However, there remains a paucity of evidence on developmental immunotoxicity of cerium. This study was designed to examine the developmental immunotoxicity of gestational and postnatal exposure to cerium nitrate (CN) in BALB/C mouse offspring. Dams were given CN by oral gavage at 0, 0.002, 0.02 and 0.2 mg/kg from gestation day 5 (GD5) to postnatal day 21 (PND 21). On PND 21, the highest dose of CN significantly suppressed the NK cell cytotoxicity, and reduced the proportions of NK cells in peripheral blood and spleen of both female and male pups, however, the proportions of monocytes in peripheral blood and macrophages in spleen only increased in female pups. For adaptive immunity, on PND 21, the suppression of T/B lymphocyte proliferation, humoral and cellular immune responses (number of splenic plaque-forming cells, PFC, and delayed-type hypersensitivity, DTH) were observed in both female and male pup mice exposed to 0.2 mg/kg CN. However, the fall of proportions of T/B lymphocytes in peripheral blood (PB), spleen and mesenteric lymph node (MLN) only found in female pups at 0.2 mg/kg on PND 21. Most indications recovered to normal after 3-week cessation of CN exposure, except the reduction of DTH and PFC. From the findings in this study, the lowest-observed-adverse-effect level (LOAEL) of CN for developmental immunotoxicity was estimated to be 0.2 mg/kg bw per day.

Tuning Compressive Young's Moduli and Antibacterial Activities of Alginate/Poly(N-isopropylacrylamide) Hydrogels with Laponite Layers and Cerium Ions

Hybrid hydrogels containing alginate (Alg) and poly(N-isopropylacrylamide) (PNIPAAm) chains as natural and synthetic components, respectively, were crosslinked using double and triple pairs of the crosslinkers Ce³⁺/Ce⁴⁺, laponite (LP) RD, and N,N'-methylenebisacrylamide (BIS). (Alg/PNIPAAm)-Ce³⁺ and (Alg/PNIPAAm-PNIPAAm)-Ce³⁺ double- and triple-network structures were prepared using multivalent cerium ions (Ce³⁺), multifunctional laponite layers (L), and/or neutral tetrafunctonal BIS molecules (B). Compressive Young's moduli, E, were tuned by the type/concentration of crosslinkers and crosslinking procedures and the concentration of Alg chains. The antibacterial activity of positively charged ions and molecules is due to the electrostatic attraction with the negatively charged bacterial cell walls. In the current study, we report the antibacterial activity on Escherichia coli of Ce³⁺ ions in the absence and presence of gentamicin sulfate (GS) for double and triple networks. Nonbacterial areas, which are called inhibition zones, around the disks, and compressive E moduli of the single and double PNIPAAm and Alg/PNIPAAm networks crosslinked by LP RD and containing Ce³⁺/Ce⁴⁺ions in free and ionically bonded states, respectively, were higher than those of the ones crosslinked with BIS. Moreover, BIS- and LP RD-crosslinked single PNIPAAm hydrogels displayed larger inhibition zones than those of Alg/PNIPAAm hybrids, supporting the antibacterial activity of free Ce³⁺/Ce⁴⁺ ions diffused together with GS molecules. On the other hand, antibacterial activities of GS + Ce³⁺-loaded triple networks were much lower than those of their double counterparts because the increase in the structural complexity reduced the co-emission of antibacterial agents.

The Use of Cerium Compounds as Antimicrobials for Biomedical Applications

Cerium and its derivatives have been used as remedies for wounds since the early 20th century. Cerium nitrate has attracted most attention in the treatment of deep burns, followed later by reports of its antimicrobial properties. Its ability to mimic and replace calcium is presumed to be a major mechanism of its beneficial action. However, despite some encouraging results, the overall data are somewhat confusing with seemingly the same compounds yielding opposing results. Despite this, cerium nitrate is currently used in wound treatment in combination with silver sulfadiazine as Flammacérium. Cerium oxide, especially in nanoparticle form (Nanoceria), has lately captured much interest due to its antibacterial properties mediated via oxidative stress, leading to an increase of published reports. The properties of Nanoceria depend on the synthesis method, their shape and size. Recently, the green synthesis route has gained a lot of interest as an alternative environmentally friendly method, resulting in production of effective antimicrobial and antifungal nanoparticles. Unfortunately, as is the case with antibiotics, emerging bacterial resistance against cerium-derived nanoparticles is a growing concern, especially in the case of bacterial biofilm. However, diverse strategies resulting from better understanding of the biology of cerium are promising. The aim of this paper is to present the progress to date in the use of cerium compounds as antimicrobials in clinical applications (in particular wound healing) and to provide an overview of the mechanisms of action of cerium at both the cellular and molecular level.

Effects of Carnosine, Ankaferd, and Silver Sulfadiazine on an Experimental Burn Model: Roles of Irisin and HSP70

In this study, the effects of carnosine, ankaferd, and 1% silver sulfadiazine applied topically on second-degree burns were investigated and the roles of irisin and Heat shock protein 70 (HSP70) in this healing process were evaluated. Ninety male albino rats were used and divided into five groups. The groups were classified as control, burn, burn + carnosine (CAR), burn + ankaferd (ABS), and burn + silver sulfadiazine (SS). It was found that level of irisin increased in the first week and decreased in the second week in the burn and CAR groups. In the ABS and SS groups, the level of irisin was determined that started to increase in the first week and continued to increase in the second week. The level of HSP70 was found to increased in the first week in burn and CAR groups and decreased in the second week, but started to increase in the second week in ABS and SS groups. Both levels of irisin and HSP70 were observed to decreased in all treatment groups in the third week. In this study, it was shown that ankaferd and silver sülfadiazine treatments cause an increase in the irisin levels in the early period and a gradually increase in HSP70 levels in the later period in burns. The inflammatory response was observed to be limited in the early period in the ankaferd and sulfadiazin groups. It was concluded that these findings were effective in early wound healing in burns.

Application of Easy Wet Healing Therapy for Chronic Noninfectious Wounds in Limbs

Chronic wounds in limbs without infection are common. This study was to identify an economical, simple, and useful wet healing therapy for patients with chronic noninfectious wounds in the limbs, especially for low-income patients. In total, 56 patients with chronic limb wounds without infection from April 2018 to March 2019 were included. They underwent wound cleaning by iodine and wound covering by recombinant human epidermal growth factor gel, zinc oxide ointment, and erythromycin eye ointment at a 1:1:1 ratio and thickness of 0.8 cm. After applying the drug, a slight-pressure dressing was applied to the wound with a cotton pad and bandage, and the dressing was changed every 3 days. All the wounds completely healed within 12 to 45 days (26.2 ± 11.9 days). The healing time showed a positive correlation with the area of the wound (r = 0.328, P < .05) and the course of disease (r = 0.485, P < .01). The healing time of deep second-degree wounds was 17.2 ± 3.3 days, which was shorter than that of deep third-degree wounds (34.8 ± 8.4 days; P < .05). There was no significant difference in the healing time according to sex. Upper limb wounds healed faster than lower limb wounds (16 ± 2.7 days versus 31.7 ± 9.7 days, P < .05). The simple therapy required a low cost of 0.07 dollars per square centimeter for each dressing change. This wet healing therapy is easy, effective, relatively safe, and affordable, with no obvious side effects.