Comparison of organic and inorganic germanium compounds in cellular radiosensitivity and preparation of germanium nanoparticles as a radiosensitizer

Purpose: The aim of this work is to compare the radiosensitizing effect between organic and inorganic germanium compounds and to investigate whether nanometer-sized germanium particles can act as radiosensitizers.

Materials and methods: Bis (2-carboxyethylgermanium) sesquioxide (Ge-132), germanium oxide (GeO₂) and germanium nanoparticles were used in this study. Cell viability was determined by clonogenic survival assay. Cellular DNA damage was evaluated by alkaline comet assay, confocal microscopy and the cellular level of phospho-histone H2AX (γ-H2AX).

Results: Nanometer-sized germanium particles were fabricated. They have a similar radiosensitizing effect as that of GeO₂. Conversely, Ge-132 did not enhance the radiosensitivity of cells. Comet assay was employed to evaluate the level of DNA damage and confirmed that inorganic germanium compounds enhanced cellular radiosensitivity. Notably, the comet assay indicated that the nanoparticle itself caused a higher level of DNA damage. The possibility that germanium nanoparticles per se caused DNA damage was ruled out when the cellular level of γ-H2AX was examined.

Conclusions: We demonstrated that inorganic but not organic germanium compounds exerted radiosensitizing effect in cells. Nanometer-sized germanium particles were fabricated and were able to enhance the radiosensitivity of cells. Confounding effect may occur when comet assay is used to estimate the level of DNA damage in the presence of germanium nanoparticles.     

The risk of cancer among patients with sleep disturbance: a nationwide retrospective study in Taiwan

PurposeTo investigate the risk of cancer among patients with nonapnea sleep disorders (SDs).MethodsWe included newly diagnosed SD patients aged 20 years and older without antecedent cancer between 2000 and 2010 from the National Health Insurance Research Database. Standardized incidence ratios (SIRs) of cancers were calculated to compare the cancer incidence of patients with SD with that of the general population.ResultsDuring the 10-year study period, 2062 cancers developed among 63,381 SD patients, who were observed for 382,826 person-years (median follow-up of 6.23 years). The SIR for all cancers was 1.19 (95% confidence interval [CI], 1.14–1.24). For specific cancer types, SD patients exhibited an increased SIR for liver and lung cancers (1.44; 95% CI, 1.28–1.61 and 1.34; 95% CI, 1.18–1.51, respectively).ConclusionsWe observed that overall cancer risk is increased among Asian SD patients. In terms of individual cancers, the risks of liver and lung cancers were elevated. Clinicians should be aware of the possibility of increased liver and lung cancers among SD patients in Taiwan. A prospective study is necessary to confirm these findings.     

Promoters of and barriers to cervical cancer screening in a rural setting in Tanzania

Objective

To investigate promoters and barriers for cervical cancer screening in rural Tanzania.

Methods

We interviewed 300 women of reproductive age living in Kiwangwa village, Tanzania. The odds of attending a free, 2-day screening service were compared with sociodemographic variables, lifestyle factors, and knowledge and attitudes surrounding cervical cancer using multivariable logistic regression.

Results

Compared with women who did not attend the screening service (n = 195), women who attended (n = 105) were older (OR 4.29; 95% CI, 1.61–11.48, age 40–49 years versus 20–29 years), listened regularly to the radio (OR 24.76; 95% CI, 11.49–53.33, listened to radio 1–3 times per week versus not at all), had a poorer quality of life (OR 4.91; CI, 1.96–12.32, lowest versus highest score), had faced cost barriers to obtaining health care in the preceding year (OR 2.24; 95% CI, 1.11–4.53, yes versus no), and held a more positive attitude toward cervical cancer screening (OR 4.64; 95% CI, 1.39–15.55, least versus most averse).

Conclusion

Efforts aimed at improving screening rates in rural Tanzania need to address both structural and individual-level barriers, including knowledge and awareness of cervical cancer prevention, cost barriers to care, and access to health information.