Degradation of diclofenac sodium using Fenton-like technology based on nano-calcium peroxide

A nano-calcium peroxide (nCaO₂) powder with a purity of 89.1% was prepared using an improved traditional method. Then, the as-prepared nCaO₂ was used as the source of hydrogen peroxide (H₂O₂) for the Fenton-like degradation of diclofenac sodium (DCF). The results showed that nCaO₂ performed better for DCF removal when compared to nCaO₂ prepared by a conventional method and commercial calcium peroxide (CaO₂). Further experimental results indicated that 97.5% of DCF could be removed in 180 min at a nCaO₂/Fe²⁺-EDTA/DCF molar ratio of 16/8-8/1, which was more efficient than in the H₂O₂/EDTA-Fe²⁺/DCF and nCaO₂/Fe²⁺/DCF systems. The best removal rate of DCF was at pH 6.0, unlike previous claims that stated that the lower the pH in the buffer system, the better the degradation of DCF. In addition, the influence of water quality parameters, such as Cl^-, NO₃^-, SO₄^2-, HCO₃^-, and humic acid (HA), on DCF removal were evaluated. A free radical masking experiment revealed the existence of hydroxyl radical (OH), superoxide radical (O₂^-) and singlet oxygen (¹O₂), and indicated that the degradation of DCF was mainly due to oxidation caused by OH. Electron paramagnetic resonance (EPR) studies for different systems and different active oxygen species were carried out, and it was further confirmed that OH radicals have high intensity in the Fenton-like system based on nCaO₂. EPR results also showed that the addition of EDTA can promote the production of OH. According to the identification of the dominant reactive species and GC-MS, the possible theoretical DCF degradation pathways were proposed.

[Removal of a giant ethmoidal sinus osteoma with orbital extension]

Osteomas are slow growing bony tumors of the nasal sinuses. Ethmoid osteomas with orbital extension are unusual. Any surgical approach has to take into account protection of the vital structures, particularly the optic nerve and internal rectus muscle, skull base. A 65-year-old man, without past medical history, was referred to our hospital with a 1-month history of double vision and persisting pain around the left eye. Three-dimensional computed tomography (CT) revealed a large calcified dense mass measuring 32 mm × 25 mm × 25 mm in the left ethmoidal sinus with orbital extension. An endoscopic endonasal approach combined with inner canthus way was planned. Most of the tumor was removed from nasal cavity, the rest part of the tumor was taken out of the inner canthus incision. The medial wall of the orbital cavity was repaired with titanium mesh. No cerebrospinal fluid (CSF) leakage was observed during the procedure. The patient recovered rapidly and had no visual impairment and occular motility disorders after operation. The double vision was alleviated and disappeared after one months. Treatment of large ethmoid osteomas requires a combined approach to prevent injury to the orbital content. The cooperation of both otolaryngologists and ophthalmologists is necessary to achieve risk-free surgery.

[Effects of di-zhen granules on catecholamine transmitter and gonadotropin of clamacteric rats with deficiency of yin brings about the interior heat-syndrome]

Fifteen-month-old Sprague-Dawley rats were given with some kinds of hot property of herb to produce model of Deficiency of yin brings about the interior heat-syndrome. The weight, water drinking volume, and body temperature of model rats were observed at the process of producing model and the treatment of di-zhen granules. Hypothalamic NE, DA and plasma NE, E concentration were determined by high-performance liquid chromatography, and serum E2, FSH, LH levels were determined by radioimmunoassay. The results were that after having been given the hot property of herbs for 2 weeks, the model rats increased water drinking volume and body temperature, which is similar to the appearance of patients with Deficiency of yin brings about the interior heat syndrome, and after having been treated with di-zhen granules, the water drinking volume and temperature of model rats decreased significantly (P < 0.01). The hypothalamic NE, DA, plasma NE, E, and the serum FSH, LH of the group treated with di-zhen granules were significantly lower than that of the model group and the normal group(P < 0.01). The results show that our model mentioned above possesses some characteristic features of the human climacteric syndrome which exhibits Deficiency of yin brings about the interior heat-syndrome. Di-zhen granules may regulate the function of GnRH neurons and other neurotic nucleus in hypothalamus, and then rectify the endocrine disorders of climacteric.

In vivo evidence of free radical formation after asbestos instillation: an ESR spin trapping investigation

It has been postulated that the in vivo toxicity of asbestos results from its catalysis of free radical generation. We examined in vivo radical production using electron spin resonance (ESR) coupled with the spin trap alpha-(4-pyridyl-1-oxide)-N-t-butylnitrone (4-POBN); 180 day-old rats were intratracheally instilled with either 500 microg crocidolite or saline. Twenty-four hours later, histologic examination revealed a neutrophilic inflammatory response. ESR spectroscopy of the chloroform extract from lungs exposed to asbestos gave a spectrum consistent with a carbon-centered radical adduct, while those spectra from lungs instilled with saline revealed a much weaker signal. This same radical formation persisted and, even one month after instillation, could be detected in the lungs of rats exposed to asbestos. The 4-POBN adducts detected by ESR are very similar to, if not identical with, ethyl and pentyl radical adducts, providing evidence of in vivo lipid peroxidation resulting from asbestos exposure. We conclude that, after instillation of crocidolite in the rat, ESR analysis of lung tissue demonstrates in vivo free radical production.

Iron supplementation generates hydroxyl radical in vivo. An ESR spin-trapping investigation

Electron spin resonance (ESR) spectroscopy has been used to investigate hydroxyl radical generation in rats with chronic dietary iron loading. A secondary radical spin-trapping technique was used where hydroxyl radical forms methyl radical upon reaction with DMSO. The methyl radical was then detected by ESR spectroscopy as its adduct with the spin trap alpha-phenyl-N-t-butylnitrone (PBN). This adduct was detected in the bile of rats 10 wk after being fed an iron-loading diet and 40 min after the i.p. injection of the spin trap PBN dissolved in DMSO. Bile samples were collected into a solution of the ferrous stabilizing chelator 2,2'-dipyridyl in order to prevent the generation of radical adducts ex vivo during bile collection. Identification of the ESR spectrum of the major radical adduct as that of PBN/.CH3 provides evidence for the generation of the hydroxyl radical during iron supplementation. Desferal completely inhibited in vivo hydroxyl radical generation stimulated by high dietary iron intake. No radical adducts were detected in rats which were fed the control diet for the same period of time. This is the first evidence of hydroxyl radical generation in chronic iron-loaded rats.

In vivo free radical generation by chromium(VI): an electron spin resonance spin-trapping investigation

Although studies in chemical and biological systems have demonstrated that free radical formation is mediated by Cr(VI), no ESR evidence for the generation of free radicals in vivo has been reported. We have employed an ESR spin-trapping technique to detect an adduct of the spin trap alpha-(4-pyridyl 1-oxide)-N-tert-butylnitrone (4-POBN) in the bile of animals given an intragastric dose of potassium dichromate. In this study, we provide evidence for in vivo radical generation resulting from Cr(VI)-poisoned rats. Upon the administration of Cr(VI) and 4-POBN, the ESR spectrum of the radical adducts present in the bile exhibited hyperfine coupling constants aN = 15.71 G and a beta H = 2.90 G. We suggest that the radical responsible for this 4-POBN adduct is carbon-centered and derived from endogenous lipids. The radical adducts detected in the bile from Cr(VI)-treated rats are proposed to be formed and trapped in the liver and excreted into bile. This is the first report of electron spin resonance evidence for the in vivo generation of free radicals by Cr(VI).