ABSTRACT
Noncoding small RNAs are the important regulators of vital processes. Through the high-throughput sequencing and analyses of small RNA fragments, a new class of non-coding small RNAs has been presented, which can be matched to the known tRNA gene. The different sources of tRFs are classified into various types depending on where they match on the parental tRNA. The tRFs can be expressed in a variety of organisms. Recent studies have found that the tRFs have a variety of biological functions in the regulation of gene expression, epigenetics，tumor suppression, neurodegeneration and so on. As a regulatory RNA, the tRFs play an important role in development and progression of tumors, and are known to play regulatory roles in the proliferation and metastasis of tumor cells. This article reviews the research progress on the classification，biological function and role of tRFs in malignant tumors.
ABSTRACT
Objective To observe the changes in retinal structure after shortpulse laser technique and conventional laser surgery.Methods Oburg fundus photography,spectral domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF) examination were performed in 16 patients (22 eyes) receiving shortpulse laser surgery,following 19 patients (25 eyes) undergoing conventional laser surgery to observe the spot situation with the time for postoperative 1 h,1-2 weeks,1-3months,＞3-6 months,＞ 6-12 months.Results After 1 h of short-pulse laser,fundus color displayed light spot of the center was white and gray,which surrounded by gray dizzy;SD-OCT images showed spot ellipsoid area formed a ring out of band,but the inner retina and retinal pigment epithelium (RPE) had no significant change.FAF showed multiple spontaneous fluorescence signals to reduce the circular area;at 1-2weeks after laser surgery,fundus photography showed spot center for white and gray,and the surrounded gray dizzy became larger,and FAF spontaneous fluorescence signal in light spot center was enhanced,while SD-OCT showed that the outer nerve sensory layer was pulled to the photocoagulation spot center.From 1 month to 3 months,some of the epithelial layers of the nerves were restored to normal,and ＞ 3-6 months,the epithelial layer of the nerve was basically restored to normal;and ＞ 6-12 months,the nerve epithelium was back to normal.As for conventional laser surgery,1 h later,fundus photography and FAF performance were similar to the short-pulse laser,and the SD-OCT showed that the whole retinal layer had dropsy in the spot place;after 1-2 weeks,the spot center was gray and white,and the surrounded gray halo turned enlargement,and FAF spontaneous fluorescence signal in light spot center was enhanced,while SD-OCT showed that the outer nerve sensory layer was pulled to the spot center with adhesion;after 1-3 months,fundus photography and FAF performance were similar to those of short-pulse laser,while SD-OCT presented the RPE cells hyperplasia and ring atrophy around the spot,and the RPE atrophy around the spot was gradually enlarged,plus the whole layer of the nerve epithelium was adhesion ＞ 3-6 months after surgery.＞6-12 months later,the results showed the RPE layer atrophy and nerve epithelium layer adhesion.The results of FAF in all follow-up groups were consistent with that of OCT results.Conclusion OCT and FAF are the important methods to observe the postoperative retinal laser structure changes,which can provide objective basis for the confirmation that short-pulse laser has less damage than the conventional laser treatment,and this provides a new research idea to optimize the laser parameters.