[Clinical analysis of endoscopic sinus surgery on 12 HIV-positive patients with sinusitis]

Objective: To explore the feasibility of endoscopic sinus surgery on HIVinfected patients. Method: Twelve positive patients suffering from sinusitis undergoing endoscopic treatment were retrospectively analyzed. And the clinical characteristics,treatment and therapeutic effects were summarized. Result: After follow-up up for 1-6 years, 8 cases were cured, 1 case was improved, and 3 cases recurred three months after operation.The effective rate was 75%.The quality of life of patients was improved. Conclusion: For HIV-positive sinusitis patients with surgical indications,endoscopic surgery should be considered if general examinations are normal and full perioperative protections can be taken, and the therapeutic efficacy is definite. CD4+ T cell count should not be regarded as an absolute contraindication of surgery.

[Clinical analysis of chronic tonsillitis in 12 HIV/AIDS patients]

Objective:To explore the clinical characteristics and efficacy of chronic tonsillitis in HIV/AIDS patients.Method:Clinical features and effects were retrospectively analyzed in 12 HIV/AIDS cases with chronic tonsillitisin.Result:All subjects were men with an average age of（26.4±8.7）years; the common clinical symptoms included sore throat(12/12),fever(7/12),snoring(6/10); tosils in these patients were most frequently found in Ⅲ grade enlargement (9/12); 11 patients who were performed tonsillectomy,were satisfied with having chosen tonsillectomy with a mean score of（9.5±0.8）,sore throat episodes and snoring were disengaged after operation in 10 cases,sore throat episodes was significantly improved from 12/year to 2/year in 1 case.Conclusion:Chronic tonsillitis in HIV/AIDS patients occurred more in young and middle-aged men with typical clinical manifestations of sore throat,fever and snoring. Under strict indication,tonsillectomy is an effective treatment for chronic tonsillitis in HIV/AIDS patients.

Effects of humic acid and ionic strength on TiO₂ nanoparticles sublethal toxicity to zebrafish

The stability and bioavailability of titanium dioxide nanoparticles (TiO2 NPs) suspension could be modified by the physicochemical properties of solution. In the present study, the effect of humic acid (HA) and ionic strength (by adding NaCl) on aggregation and sedimentation of TiO2 NPs suspension were investigated. Accordingly, the sublethal toxicity of TiO2 NPs suspensions with different HA and NaCl concentrations toward zebrafish (Danio rerio) was evaluated by monitoring the changes of superoxide dismutase, catalase, malonaldehyde and glutathione in gill, liver and intestine. The results showed that the aggregations formation and hydrodynamic diameter of TiO2 NPs in suspensions are not essential characteristics to decide toxicity. The varied oxidative stress responses detected in gill, liver and intestine derived from different toxicity mechanisms of TiO2 NPs. Nevertheless, the oxidative stress could be suppressed by the adding of HA and/or the increase of ionic strength, which can decrease the bioavailability of TiO2 NPs in water. The study suggests that the environmental factors, such as HA and ionic strength, are important for the fate (aggregation and sedimentation) and toxicity of nanomaterials in aquatic environment.

The effect of 125I decay at different stages of S-phase on survival, expression of micronuclei and chromosome aberrations in CHO cells

Chinese hamster ovary (CHO) cells were synchronized in M phase by mitotic selection, and then re-synchronized with aphidicolin at the G1/S phase border. The cells were labelled in early-S phase by 10 min exposure to 125I-iododeoxyuridine and then cultured (chased) in non-radioactive medium for 0.5, 3 or 5h, followed by harvesting and freezing to accumulate the desired number of 125I decays. Cell damage was assessed by evaluating colony formation, micronucleus formation and chromosome aberrations. These biological estimators of damage showed that the cytocidal effect of 125I decay increased with the duration of the post-labelling chase period: the highest level of damage was found in cells from the 5 h chase period and the lowest in the cells from the 0.5 h chase period. Survival curves for the three chase periods displayed low-dose hyper-radiosensitivity for 0 to 20 125I decays cell-1. The results indicate that the repair of DNA double-strand breaks (DSBs) may depend on the maturation stage of chromatin and an explanation of this finding is proposed which invokes the homologous recombination model for DSB repair.

Low-LET and high-LET radiation action of 125I decays in DNA: effect of cysteamine on micronucleus formation and cell killing

Chinese hamster ovary cells were pulse-labeled with 125I-iododeoxyuridine during early S phase, and cell samples were harvested 30 min or 5 h after labeling. The samples were frozen (with or without 25 mM cysteamine) and stored at -196 degrees C for accumulation of 125I decays. X-ray control experiments were performed at 37 degrees C and -196 degrees C. Aliquots of cells were plated for evaluating micronucleus formation and cell survival. The results demonstrated a striking shift in micronucleus formation and cell death with time after labeling. Cells frozen 30 min after labeling exhibited effects typical of low-LET radiation, but cells frozen 5 h after labeling showed a response characteristic of high-LET radiation. Cysteamine provided protection against the effects of 125I during the initial phase of effects characteristic of low-LET radiation, but no protection was seen during the phase characteristic of high-LET radiation. When cell survival was evaluated as a function of micronucleus frequency rather than dose in decays/cell, the survival curves for all treatment groups became superimposed. Previous work using the same experimental system had failed to show a direct link between 125I-induced DNA double-strand breaks and cell death. These findings are consistent with the hypothesis that DNA damage may not be the sole mechanism for cell killing and that damage to higher-order structures in the cell nucleus may contribute to (or modify) radiation-induced cell death.