Unilateral Biportal Endoscopic Laminectomy for Treating Cervical Stenosis: A Technical Note and Preliminary Results.

Objective: The objective of this study was to introduce a surgical technique for the percutaneous decompression of cervical stenosis (CS) using a unilateral biportal endoscopic approach and characterize its early clinical and radiographic results. Materials and Methods: Nineteen consecutive patients with CS who needed surgical intervention were recruited. All enrolled patients underwent unilateral biportal endoscopic laminectomy (UBEL). All patients were followed postoperatively for >1 year. The preoperative and final follow-up evaluations included the Japanese Orthopedic Association (JOA) score for neurological assessment, visual analogue scale (VAS) for axial pain and C2-C7 Cobb angle for cervical sagittal alignment. The postoperative complications were analyzed. Results: Thirteen males and six females were included in the analysis. The mean follow-up period was 16.3 ± 2.6 months. The mean operative time was 82.6 ± 18.4 min. Postoperative MRI and CT revealed ideal neural decompression of the treated segments in all patients. Preoperative VAS and JOA scores improved significantly after the surgery, and cervical lordosis was preserved on the postoperative images. Conclusions: UBEL was an effective surgical method for CS, which may also minimize iatrogenic damage to the posterior tension band (PTB) and help to maximize the preservation of the cervical lordosis.

An endogenous microRNA (miRNA1166.1) can regulate photobio-H2 production in eukaryotic green alga Chlamydomonas reinhardtii.

BACKGROUND: Hydrogen photoproduction from green microalgae is regarded as a promising alternative solution for energy problems. However, the simultaneous oxygen evolution from microalgae can prevent continuous hydrogen production due to the hypersensitivity of hydrogenases to oxygen. Sulfur deprivation can extend the duration of algal hydrogen production, but it is uneconomical to alternately culture algal cells in sulfur-sufficient and sulfur-deprived media. RESULTS: In this study, we developed a novel way to simulate sulfur-deprivation treatment while constantly maintaining microalgal cells in sulfur-sufficient culture medium by overexpressing an endogenous microRNA (miR1166.1). Based on our previous RNA-seq analysis in the model green alga Chlamydomonas reinhardtii, three endogenous miRNAs responsive to sulfur deprivation (cre-miR1166.1, cre-miR1150.3, and cre-miR1158) were selected. Heat-inducible expression vectors containing the selected miRNAs were constructed and transformed into C. reinhardtii. Comparison of H2 production following heat induction in the three transgenic strains and untransformed control group identified miR1166.1 as the best candidate for H2 production regulation. Moreover, enhanced photobio-H2 production was observed with repeated induction of miR1166.1 expression. CONCLUSIONS: This study is the first to identify a physiological function of endogenous miR1166.1 and to show that a natural miRNA can regulate hydrogen photoproduction in the unicellular model organism C. reinhardtii.

Improved photobio-H2 production regulated by artificial miRNA targeting psbA in green microalga Chlamydomonas reinhardtii.

BACKGROUND: Sulfur-deprived cultivation of Chlamydomonas reinhardtii, referred as "two-stage culture" transferring the cells from regular algal medium to sulfur-deplete one, has been extensively studied to improve photobio-H2 production in this green microalga. During sulfur-deprivation treatment, the synthesis of a key component of photosystem II complex, D1 protein, was inhibited and improved photobio-H2 production could be established in C. reinhardtii. However, separation of algal cells from a regular liquid culture medium to a sulfur-deprived one is not only a discontinuous process, but also a cost- and time-consuming operation. More applicable and economic alternatives for sustained H2 production by C. reinhardtii are still highly required. RESULTS: In the present study, a significant improvement in photobio-H2 production was observed in the transgenic green microalga C. reinhardtii, which employed a newly designed strategy based on a heat-inducible artificial miRNA (amiRNA) expression system targeting D1-encoded gene, psbA. A transgenic algal strain referred as "amiRNA-D1" has been successfully obtained by transforming the expression vector containing a heat-inducible promoter. After heat shock conducted in the same algal cultures, the expression of amiRNA-D1 was detected increased 15-fold accompanied with a 73% decrease of target gene psbA. More interestingly, this transgenic alga accumulated about 60% more H2 content than the wild-type strain CC-849 at the end of 7-day cultivation. CONCLUSIONS: The photobio-H2 production in the engineered transgenic alga was significantly improved. Without imposing any nutrient-deprived stress, this novel strategy provided a convenient and efficient way for regulation of photobio-H2 production in green microalga by simply "turn on" the expression of a designed amiRNA.