NaYbF4 nanoparticles as near infrared light excited inorganic photosensitizers for deep penetration in photodynamic therapy.

Photodynamic therapy (PDT) is a non-invasive therapy with many advantages over other therapeutic methods, but it is restricted to treat superficial cancers due to the shallow tissue penetration of visible light. The biological window in the near infrared region (NIR) offers hope to extend the penetration depth, but there is no natural NIR excited photosensitizer. Here, we report a novel photosensitizer: NaYbF4 nanoparticles (NPs). By using a 1,3-diphenylisobenzofuran (DPBF) sensor, we show that the Yb3+ ions can absorb the NIR light and transfer energy directly to oxygen to generate reactive oxygen species (ROS). The efficiency of transferring energy to oxygen by NaYbF4 NPs is comparable to that of traditional photosensitizers. We have carried out PDT both in vitro and in vivo based on NaYbF4 NPs; the results demonstrate that NaYbF4 NPs are indeed an effective NIR photosensitizer, which can help extend the application of PDT to solid tumors owing to the much deeper penetration depth of NIR light.

The preparation of rat's acellular spinal cord scaffold and co-culture with rat's spinal cord neuron in vitro.

STUDY DESIGN: The rat's acellular spinal cord scaffold (ASCS) and spinal cord neurons were prepared in vitro to explore their biocompatibility. OBJECTIVES: The preparation of ASCS and co-culture with neuron may lay a foundation for clinical treatment of spinal cord injury (SCI). SETTING: Tianjin Medical University General Hospital, ChinaMethods:ASCS was prepared by chemical extraction method. Hematoxylin and eosin (H&E), myelin staining and scanning electron microscope were used to observe the surface structure of ASCS. Spinal cord neurons of rat were separated in vitro, and then co-cultured with prepared ASCS in virto. RESULTS: The prepared ASCS showed mesh structure with small holes of different sizes. H&E staining showed that cell components were all removed. The ASCS possessed fine three-dimensional network porous structure. DNA components were not found in the ASCS by DNA agarose gel electrophoresis. The cultured cells express neuron-specific enolase (NSE) antigen with long axons. H&E staining showed that the neurons adhered to the pore structures of ASCS, and the cell growth was fine. The survival rate of co-cultured cells was (97.53±1.52%) by MTT detection. Immunohistochemical staining showed that neurons on the scaffold expressed NSE and NeuN antigen. Cells were arranged closely, and the channel structures of ASCS were fully filled with neurons. The cells accumulated in the channel and grew well in good state. CONCLUSION: The structure of ASCS remained intact, and the neurons were closely arranged in the scaffolds. These results may lay a solid foundation for clinical treatment of SCI when considering glial scar replacement by biomaterials.

Epidemiology of traumatic spinal cord injury in Tianjin, China.

STUDY DESIGN: A retrospective epidemiological study. OBJECTIVES: To provide recent epidemiological characteristics of traumatic spinal cord injuries (TSCIs) in adults living in Tianjin. SETTING: Tianjin, China. METHODS: This study included all TSCI patients aged 15 years or older who were admitted to tertiary hospitals in Tianjin from 2004 to 2008. Epidemiological characteristics, such as age, sex, date of admission, causes of injury, level of injury, America Spinal Injury Association impairment scale and date of discharge were included. RESULTS: A total of 869 patients were included, with an estimated annual incidence was 23.7 per million populations. The male/female ratio was 5.63:1. Mean age of TSCI was 46.0±14.2 years (men 45.8±14.2 years, women 47.5±14.5 years), with a range of 16-90 years. Falls were regarded as the leading causes of injury, followed by motor vehicle collisions. The lesion level was cervical in 71.5%, thoracic in 13.3% and lumbar/sacral in 15.1%. The frequency of tetraplegia (71.5%) was higher than paraplegia (28.5%), and roughly four-fifth of tetraplegia cases were incomplete injury. CONCLUSION: To our knowledge, national or local epidemiological study of spinal cord injury (SCI) has not been carried out previously in China. The number of SCI patients in this country is large and would increase gradually. Similar to other developing countries, falls were the main causes of TSCI. Low falls were more common in those over 60 years old. As the ageing society coming, the number of low falls-induced TSCI would increase gradually, which poses a challenge to the society health system.