Modulation of N-nitrosodiethylamine-induced hamster lung tumors by ozone

Intra-tumoral treatment with oxygen-ozone in glioblastoma: A systematic literature search and results of a case series

Despite progress in surgery and radiochemotherapy, the prognosis of glioblastoma (GB) remains poor. GB cells exhibit a preference for hypoxia to maintain their tumor-forming capacity. Treatment strategies utilizing oxygen (O₂) or ozone (O3) and generating reactive oxygen species induce cell growth inhibition and apoptosis. The anti-tumorigenic properties of O2-O3 are accompanied by a key role in regulating immunogenicity. The present study reported a case series of an intra-tumoral O2-O3 application in recurrent GB. Following surgery in combination with standard radiochemotherapy, O2-O3 (5 ml at 40 µg/ml) was applied every four weeks into the tumor vicinity. The patients received a median of 27 (range, 3–44) O2-O3 applications. In addition, a systematic literature search was performed in order to evaluate the role of O3 in the treatment of malignancies. The median overall survival rate was 40 (range, 16–53) months. The median survival rate following the first recurrence or the initiation of the O2-O3 treatment, respectively, was 34 (range, 12–53) months. In one patient, a local infection and in another, hemorrhage occurred, necessitating in both the temporary removal of the reservoir. The data from the present study support the potential benefit of an intra-tumoral O2-O3 application in recurrent GB. The scientific literature revealed by the bibliographic search suggests that O3 may be considered a viable adjuvant therapy in oncological patients. The present study may serve as a starting point for further observational and clinical studies elucidating the cellular and systemic effects of O2 and/or O3 and demonstrating their efficacy and safety in larger patient samples.

Grain sorghum dust increases macromolecular efflux from the in situ nasal mucosa

The purpose of this study was to determine whether an aqueous extract of grain sorghum dust increases macromolecular efflux from the nasal mucosa in vivo and, if so, whether this response is mediated, in part, by substance P. Suffusion of grain sorghum dust extract on the in situ nasal mucosa of anesthetized hamsters elicits a significant increase in clearance of fluorescein isothiocyanate-labeled dextran (FITC-dextran; mol mass, 70 kDa; P < 0.05). This response is significantly attenuated by CP-96345 and RP-67580, two selective, but structurally distinct, nonpeptide neurokinin 1 (substance P)-receptor antagonists, but not by CP-96344, the 2R,3R enantiomer of CP-96345 (P < 0.05). CP-96345 has no significant effects on adenosine-induced increase in clearance of FITC-dextran from the in situ nasal mucosa. CP-96345 and RP-67580, but not CP-96344, significantly attenuate substance P-induced increases in clearance of FITC-dextran from the in situ nasal mucosa (P < 0.05). Collectively, these data suggest that grain sorghum dust elicits neurogenic plasma exudation from the in situ nasal mucosa.

Long-term toxicity studies of ozone in F344/N rats and B6C3F1 mice

The toxicity and carcinogenicity of ozone was evaluated in Fischer 344/N rats and B6C3F1 mice exposed to 0, 0.12 (2 years only), 0.5 or 1.0 ppm ozone by inhalation for 2-year and lifetime exposures. A 2-year cocarcinogenicity study (male rats only) included the subcutaneous administration of 0, 0.1 or 1.0 mg/kg/body wt. of 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) for the first 20 weeks along with inhalation exposure to 0 or 0.5 ppm ozone followed by additional 84 weeks of ozone exposure alone. Ozone exposure in rats did not cause an increased incidence of lung neoplasms. In the cocarcinogenicity study, ozone exposure did not have an additive carcinogenic effect. Lifetime and 2-year ozone exposure was associated with a marginal increase in lung tumors in male B6C3F1 mice and a more pronounced increase in females. Unique mutations in the K-ras gene were found in the mouse lung neoplasms from the ozone-exposed mice.

Toxicology and carcinogenesis studies of ozone and ozone 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone in Fischer-344/N rats

The purpose of this study was to evaluate the toxicity and potential carcinogenicity or cocarcinogenicity of ozone exposure in rats. Fischer-344/N (F-344/N) rats were exposed 6 hr/day, 5 days/wk, to 0, 0.12, 0.5, or 1.0 ppm ozone by inhalation for 2-yr and lifetime exposures. The cocarcinogenicity study included subcutaneous administration of 0, 0.1, or 1.0 mg/kg body weight of 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK) and inhalation of 0 or 0.5 ppm ozone to male rats. NNK was administered by subcutaneous injections 3 times per week for the first 20 wk with ozone inhalation exposure. The ozone inhalation exposure was for 2 yr (104 wk), including the first 20 wk of NNK treatment and continuing for 84 wk after the last NNK injection. Ozone exposure caused a concentration-related increase in inflammation of the centriacinar region of the lung. There was also increased fibrosis and an extension of the bronchiolar epithelium in these centriacinar regions to involve the proximal alveoli. There was no increased incidence of neoplasms at any site, including the lung, that was associated with ozone exposure. Rats administered 1.0 mg/kg body weight NNK alone had an increased incidence of bronchiolar/alveolar neoplasms, but this effect was not enhanced by ozone exposure. Ozone exposure for 2 yr and lifetime was associated with site-specific toxic alterations in the nasal passage and lung similar to those previously described for short-term exposures. While there was significant attenuation of the pulmonary lesions as compared to short-term exposures, lesions persisted in the lifetime study and there was evidence of a mild progressive fibrosis. We conclude that under the conditions of these studies: (a) ozone exposure is not carcinogenic to either male or female F-344/N rats, (b) ozone does not enhance the incidence of pulmonary neoplasms in F-344/N rats exposed to a known pulmonary carcinogen (NNK), and (c) mild site-specific toxic lesions characteristic of ozone exposure persist in the nasal passage and lung throughout the lifetime of the rat with continued ozone exposure.