AIM:To investigate the histone modification changes of topoisomerase Ⅱα( TOPOⅡα) promoter regulatory factor Sp1 in the patients with chronic benzene poisoning .METHODS:The bone marrow samples were collect-ed from 25 chronic benzene poisoning cases and 25 controls.The chromatin immunoprecipitation assay was carried out to study the possible mechanism of TOPOⅡαpromoter regulatory factor Sp 1 expression changes .The mRNA expression of Sp1 was detected by RT-PCR.RESULTS:Compared with the controls , the histone H4 acetylation and histone H3 acetyla-tion of Sp1 in the chronic benzene poisoning patients significantly decreased (P<0.01), and histone H3K9 methylation level of Sp1 increased (P<0.01), but the histone H3K4 methylation level of SP1 was not obviously changed (P>0.05). The mRNA expression of Sp1 in the chronic benzene poisoning patients was significantly lower than that in the controls (P<0.05).CONCLUSION:In chronic benzene poisoning patients , the histone acetylation and methylation modification changes of TOPOⅡαpromoter regulatory factor Sp 1 accompanied with the changes of mRNA level are observed .Histone H4 and H3 acetylation and H3K9 methylation modification of Sp1 may play an important role in the benzene ’s hematopoiet-ic toxicities.

Objective To summarize the clinical features and visual outcome of posterior scleritis presented with symptoms involving affected optic nerve.Methods Retrospective case series study.Twelve eyes of 12 female patients with posterior scleritis were included in this study.The average age was 35.2± 14.31 years old.The patients got diagnosed with an average of 24.75 ± 22.91 days.Ocular pain was complained in all patients,and blurred vision in 11 patients.The best corrected visual acuity (BCVA),intraocular pressure (IOP),slit lamp microscope examination,B-scan ultrasound,optical coherence tomography (OCT),fundus photography,fundus fluorescein angiography (FFA) and ocular wall thickness measurement were performed in all patients.Nine eyes received visual field examination.All patients received systemic corticosteroid and steroidal eye drops for 3 months.Clinical features and outcome were retrospectively studied.Results Before treatment,the BCVA was from ＜0.1 to ＞0.8.There were 3 eyes with scleral hyperemia,3 eyes with anterior chamber flares,12 eyes with papilledema and different degrees of retinal vein dilatation,3 eyes with star-shaped macular exudates and 2 eyes with macular retinal pigment epithelium detachment.B-scan ultrasound demonstrated that the ocular walls were thickening in all eyes with typical T-sign,and the average thickness was 2.76± 0.68 mm.OCT demonstrated optic disc swelling,and the macular retinal detachment in 2 eyes.In the FFA examination,the fluorescein leakage of the disc was enhanced with time.In the Humphrey test,the value of mean deviation (MD) was 12.56± 5.73 dB and pattern standard deviation (PSD) was 8.15±4.23 dB in 9 eyes before the treatment.After treatment for 3 months,the symptoms were attenuated and the visual acuity was obviously improved with BCVA＞0.1 in all eyes.Scleral hyperemia and anterior chamber flares were only found in 1 eye.The optic disc edema gradually faded away.The ocular wall thickness in the poster part of the eyeball decreased,and the T-sign disappeared in all eyes,the average thickness was 1.53±0.41 mm.Compared with parameters before the treatment,the difference was statistically significant (t=0.003 5,P＜0.05).OCT demonstrated the recovery of the macular retinal detachment.There was no abnormal leakage evidenced in FFA in the optic disc and macular.After treatment,the value of MD and PSD was 5.19±4.82 dB and (4.33 ±3.76) dB,respectively.The difference of MD value between before and after the treatment was significant (t=0.026,P＜0.05).Conclusions Posterior scleritis with an initial symptom of optic nerve was tend to affect middle-aged patients,with clinical manifestations of anterior segment signs in some patients and optic disc swelling with retinal vein dilatation in all patients.B ultrasound examination showed typical T sign.Systemic corticosteroid treatment always obtained remission of the ocular inflammatory activity,and could achieve favorable visual outcome.

Objective: To evaluate the clinical efficacy of digitally guided precision crown lengthening in secondary aesthetic rehabilitation cases, and to provide a clinical reference for digitally guided crown lengthening procedures and secondary aesthetic restorations. Methods: We present a case of a patient with tetracycline-stained teeth, partial detachment of anterior resin veneers, and gingival margin discrepancies. The patient underwent digitally guided precision crown lengthening followed by secondary aesthetic rehabilitation. Multimodal data, including intraoral, facial, and CBCT scans, were integrated to construct a four-dimensional virtual patient model (incorporating teeth, face, bone, and occlusion) for surgical planning and 3D-printed guide fabrication. Secondary aesthetic restoration was performed after achieving stable post-surgical outcomes. Based on this case, we conducted a detailed analysis and reviewed relevant literature on crown lengthening in secondary aesthetic rehabilitation. Results: The gingival contour of the anterior teeth exhibited significant improvement, with enhanced symmetry and stable gingival margin positioning that closely matched the preoperative design. The crown lengthening procedure demonstrated high precision, and the final outcome was aesthetic and functional. Literature review indicated that secondary restorations frequently present challenges such as gingival contour discrepancies and inflammation. Aesthetic crown lengthening in the anterior region should optimize both soft and hard tissue morphology to meet aesthetic standards, with digital technology improving procedural accuracy. Conclusion Precision crown lengthening effectively addresses gingival margin discrepancies in secondary aesthetic rehabilitation, ensuring stable gingival positioning and superior aesthetic outcomes. This approach is particularly suitable for cases with high aesthetic demands.