Radiotherapy is necessary for 70% of malignant tumor patients. Local recurrence and metastasis are primary failure models, where radioresistance is one of important factors. It is critical to establish radioresistant tumor cell lines for understanding the mechanism of radioresistance. According to single radiation, fractioned radiation and the compound radiation method, four representative radiation models are classified: conventional radiation, repeated radiation, gradient radiation and other radiation. These different radiation models have difference in total dose and radiation model as well as the biological characteristics. Superior to other three models, the gradient fractioned irradiation model increase fractioned doses gradually along with the enhancement of radioresistance, which favorably balances the fractioned doses and the time of irradiated cells approaching to exponential growth phase. Clinically relevant radioresistant cell line (CRR) with a genotype in consistent with its parental cells is an important research direction on tumor radioresistance.
Key words:
Radiotherapy; Radiosensitivity; Radioresistance; Gradient irradiation
The aim of this study was to evaluate the surface roughness and wettability of dentin following ultrashort pulsed laser ablation with different levels of fluence and pulse overlap (PO). Twenty-five extracted human teeth crowns were cut longitudinally into slices of approximately 1.5-mm thick and randomly divided into nine groups of five. Samples in groups 1 to 8 were ablated with an ultrashort pulsed laser through a galvanometric scanning system. Samples in group 9 were prepared using a mechanical rotary instrument. The surface roughness of samples from each group was then measured using a three-dimensional profile measurement laser microscope, and wettability was evaluated by measuring the contact angle of a drop of water on the prepared dentin surface using an optical contact angle measuring device. The results showed that both laser fluence and PO had an effect on dentin surface roughness. Specifically, a higher PO decreased dentin surface roughness and reduced the effect of high-laser fluence on decreasing the surface roughness in some groups. Furthermore, all ablated dentin showed a contact angle of approximately 0 deg, meaning that laser ablation significantly improved wettability. Adjustment of ultrashort pulsed laser parameters can, therefore, significantly alter dentin surface roughness and wettability.
This study aimed to investigate the completion rate, visual performance, and adverse outcomes of femtosecond laser-assisted cataract surgery (FLACS) in Chinese patients. This is a prospective, single-arm, multicenter registry study of 19 cataract surgery clinics in China. Chinese patients with cataract who underwent FLACS using the Alcon LenSx® laser system in single eye (n = 1140) or both eyes (n = 201) were enrolled and data were collected between March 2015 and August 2016. Clinical characteristics were recorded before surgery, and on postoperative days 1, 7, and 30. For surgery on both eyes, the second eye was included in the analysis only if it was operated within 30 days after the first eye surgery. The primary outcome was the completion rate of circular anterior capsulotomy. Secondary outcomes for lens fragmentation, corneal incision, and intraocular lens (IOL) implantation included best corrected distance visual acuity (BCDVA) and completion rates. Adverse events (AEs) were recorded. The completion rates of circular anterior capsulotomy, lens fragmentation, corneal incision, and IOL implantation were 98.6% (95% CI: 97.8–99.1%), 99.5% (95% CI: 99.1–99.8%), 97.6% (95% CI: 96.7–98.3%), and 100% (95% CI: 99.8–100%), respectively. BCDVA preoperatively and at postoperative day 30 were 1.134 ± 0.831 logMAR and 0.158 ± 0.291 logMAR, respectively. The proportion of eyes with BCDVA of 20/20 or better was 1.6% at baseline and 41.3% at postoperative day 30. AE incidence was 0.32%, with posterior capsule rupture present in 0.19% of eyes. FLACS using the LenSx® laser system can achieve satisfactory results in a real-world setting.
OBJECTIVE To transfer the gene encoding mammalian aFGF to rabbit corneal endothelial cell and determine transfection efficiency and the effect of Ad-aFGF on proliferation of RCEC. METHODS Replication-defective adenovirus was used to deliver the LacZ reporter gene to RCEC to determine transfection efficiency by X-gal staining. A cDNA encoding mammalian aFGF was cloned into an adenoviral vector that was used to transfect RCEC. The expression of aFGF gene mRNA and protein were demonstrated by Reverse transcription PCR and Western blot respectively. The effect of Ad-aFGF on proliferation of RCEC was determined by MTT assay. RESULTS RT-PCR and Western blot from RCEC infected with Ad-aFGF for 48 h detected a specific cDNA amplification and protein expression of aFGF gene, and no positive result in control cells. Consistently, RCEC infected by MOI 20 of Ad-aFGF demonstrated an enhanced RCEC proliferation compared to controls (F = 217.107, P < 0.05). CONCLUSION Adenoviral-mediated expression of aFGF can stimulate the proliferation of RCEC.
Abstract Purpose To observe the distribution characteristics of corneal higher-order aberrations (HOAs) in cataract patients, and analyze the relationship of HOAs with patients’ age and ocular biometric parameters. Methods This retrospective study reviews the patients with cataract in Wuhan Aier Eye Department from January to August 2022. Root mean square (RMS) of the total HOA (tHOA), spherical aberration (SA), coma and trefoil aberration of the anterior cornea at central 4 and 6 mm optic zone were measured by the Wavefront Aberrometer (OPD-Scan III; Nidek Inc, Tokyo, Japan). The biometric parameters including axial length (AL), keratometry (K), central corneal thickness (CCT) and lens thickness (LT) were measured by swept-source coherence laser interferometry (OA-2000; TOMEY Corp, Aichi, Japan). Subgroup analyses and multiple linear regression analyses were used to determine whether HOAs were associated with age and ocular biometric parameters. Results A total of 976 patients (976 eyes) were included, averagely aged 65 years. At central 4 and 6 mm optic zone, the mean RMS of tHOA were respectively 0.20 and 0.65 μm, the SA were 0.06 and 0.30 μm, the coma aberration were 0.11 and 0.35 μm, and the trefoil aberration were 0.12 and 0.30 μm. The tHOA decreased with age until 60 years and then started to increase afterwards. The tHOA, coma and trefoil aberration increased with corneal astigmatism. The tHOA, SA, and coma aberration differ among different AL groups, and emmetropes had the smallest tHOA, SA, and coma aberration. Conclusions With increasing age, the value of tHOA decrease first and started increasing at 60 years. The trends of corneal HOAs are consistent with corneal low-order aberrations. The values of tHOA, SA and coma aberration were the smallest in emmetropic eyes.
p38 mitogen-activated protein kinases (p38) has been shown to be activated in hematopoietic stem and progenitors cells after exposure to ionizing radiation (IR) and its activation has been implicated in bone marrow (BM) suppression under various pathological conditions. Therefore, in the present study we investigated whether inhibition of p38 activity alone with SB203580 (SB, a specific p38 inhibitor) or in combination with granulocyte colony-stimulating factor (G-CSF) can mitigate total body irradiation (TBI)-induced BM damage and lethality. Our results showed that p38 inhibition with SB had no significant effect on the 30-day survival rates of the mice exposed to 7.2 Gy TBI when it was used alone but increased the survival of the mice when it was combined with G-CSF. This combined effect may be attributable to a better preservation or stimulation of hematopoietic stem and progenitor cells, because BM cells from SB and G-CSF-treated mice produced more colony forming units-granulocyte-macrophage (CFU-GM) and 4-week cobblestone area forming cells (CAFCs) than the cells from either SB or G-CSF-treated mice after TBI in a colony forming cell assay and a CAFC assay, respectively. These findings suggest that the combined therapy with SB and G-GSF is more effective in mitigating TBI-induced acute BM injury than either agent alone.
A coupling cavity named cascaded barbell shape cavity is proposed to resolve difficulties that multiple beam devices encountered in sub-terahertz and terahertz bands. Simulation results have confirmed our hypothesis that two barbell shape cavities operating at $TM_{310}$ mode can be concatenated with the same side cavity. Compared with the traditional barbell cavity, the novel cavity demonstrated gratifying properties in enlarging cavity, improving characteristic impedance, decreasing size sensitivity, and lowering cathode loading. Based on such a cavity, we have designed a high-efficiency V-band klystron with genetic algorithm optimization. Driven by five 60 kV 5 A pencil beams, the klystron can produce 453 kW output power, and the corresponding efficiency is 30.2%. The proposed cascaded barbell shape cavity demonstrates great power potential in V-band. The topology can also be used in coupling cavity design in terahertz bands and improve devices' output power several times.
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