[Preliminary study of the antibacterial effect on the conjunctival sac and the influence on the corneal epithelium of domestic 5% povidone-iodine before cataract extraction].

Objective: To investigate the efficacy and adverse reactions of 5% povidone-iodine in removing bacteria from the conjunctival sac with different durations. Methods: Randomized controlled study. A total of 420 patients who underwent cataract surgery in Daping Hospital, Army Medical University from December 2017 to June 2018 were selected. Non-surgical eyes (420 eyes) were selected as the study subjects and divided into 4 groups randomly: 30-second group, 1.0-min group, 2.0-min group and 3.5-min group. On the day of surgery, domestic 5% povidone-iodine was used to flush the conjunctival sac for 30 seconds, 1.0 min, 2.0 min and 3.5 min, respectively. The conjunctival sac specimens were collected for bacterial culture and bacterial identification before and after flushing the conjunctival sac with povidone-iodine. The positive rates of bacterial culture and bacterial growth were compared. The patients' ocular surface was observed and the incidence of corneal epithelial injury was recorded at 1 hour and 1 day after surgery. The positive rates of bacterial culture and corneal epithelial injury between groups were compared by Pearson chi-square test. Results: After excluding 20 patients with suspected specimens contamination, 400 patients (400 non-surgical eyes) were enrolled, including 191 males and 209 females, with an average age of 66.8 years. Before flushing the conjunctival sac, the positive rates of bacterial culture in the 30-second group, 1.0-min group, 2.0-min group and 3.5-min group were 44.8% (43/96), 43.3% (39/90), 43.1% (47/109) and 43.8% (46/105), respectively, with no statistically significant difference (χ(2)=0.066, P=0.996). After flushing, the positive rates of conjunctival sac bacterial culture in the 4 groups were 29.2% (28/96), 31.1% (28/90), 13.8% (15/109) and 13.3% (14/105), respectively. The differences between the 30-second group and 2.0-min group (χ(2)=7.308, P=0.007), between the 1.0-min group and 2.0-min group (χ(2)=8.760, P=0.003), between the 30-second group and 3.5-min group (χ(2)=7.606, P=0.006), and between the 1.0-min group and 3.5-min group (χ(2)=9.063, P=0.003) were statistically significant. At 1 hour after surgery, mild corneal epithelial injury occurred in each group, with a rate of 16.7% (16/96), 18.9% (17/90), 20.2% (22/109) and 34.3% (36/105), respectively. The differences between the 30-second group and 3.5-min group (χ(2)=8.118, P=0.004), between the 1.0-min group and 3.5-min group (χ(2)=5.804, P=0.016), and between the 2.0-min group and 3.5-min group (χ(2)=5.383, P=0.020) were statistically significant. At 1 day after surgery, there was no occurrence of new injury, and the incidence of mild corneal injury in each group was 3.1% (3/96), 5.6% (5/90), 9.2% (10/109) and 15.2% (16/105), respectively. There was statistically significant difference between the 30-second group and 3.5-min group (χ(2)=8.597, P=0.003), and between the 1.0-min group and 3.5-min group (χ(2)=4.728, P=0.030). The corneal epithelial injury healed completely at 1 week after surgery. Conclusions: The preoperative bacterial load of the conjunctival sac is more effectively reduced with 5% povidone-iodine in the 2.0-min and 3.5-min than in the 30-second and 1.0-min, and the 2-min is superior to the 3.5-min in the occurrence of corneal epithelial injury at 1 hour after surgery. Irrigation of the conjunctival sac with 5% povidone-iodine for 2 min is effective and safe, which can be an alternative measure. (Chin J Ophthalmol, 2019, 55: 509-514).

[Clinical study of the cytokine panel in the diagnosis of ocular chronic graft-versus-host disease].

Objective: To investigate the association between cytokines and ocular chronic graft-versus-host disease (cGVHD) and identify specific biomarkers for ocular cGVHD to enhance clinical diagnosis, treatment, and evaluation. Methods: A mouse model of cGVHD was established to explore the correlation between cGVHD and serum cytokines. Based on the findings from the animal experiments and literature review, a panel of 16 cytokine combinations was identified. Enzyme-linked immunosorbent assay (ELISA) was used to compare the cytokine concentrations in the serum and tear samples from patients who underwent allogeneic hematopoietic stem cell transplantation from June 2017 to March 2022 at the Medical Center of Hematology, Xinqiao Hospital, Army Medical University. Results: ① Compared with the control group, mice with cGVHD exhibited elevated serum IL-1ß, IL-6, IL-8, IL-17, IFN-γ, CX3CL1, CXCL11, CXCL13, CCL11, and CCL19 concentrations (all P<0.05). ② Analysis of the cytokine profiles of the serum and tear samples revealed that compared with patients without ocular cGVHD, those with ocular cGVHD exhibited increased serum IL-8 [P=0.032, area under the curve (AUC) =0.678]; decreased serum IL-10 (P=0.030, AUC=0.701) ; elevated IL-8, IFN-γ, CXCL9, and CCL17 in tear samples; and lower IL-10 and CCL19 in tear samples (all P<0.05, all AUC>0.7). Moreover, cytokines in tear samples showed correlations with ocular surface parameters related to ocular cGVHD. Conclusions: Tear fluid demonstrates greater specificity and sensitivity as a biomarker for diagnosing ocular cGVHD than serum biomarkers. Among the identified cytokines in tear samples, IL-8, IL-10, IFN-γ, CXCL9, CCL17, and CCL19 serve as diagnostic biomarkers for ocular cGVHD post-transplantation, offering practical reference value for diagnosis.

NMR study of self-paired parallel duplex of d(AAAAACCCCC) in solution.

The oligonucleotide d(A5C5) in solution forms a parallel self-duplex at neutral and low pH values. H2O NMR spectra at pH 5.1 indicate the presence of five imino resonances at lower temperatures; and the structure is stable up to 60 degrees C. These signals can arise only from the hemiprotonated C+.C pairs [Westhof, E. and Sundaralingham, M. (1980) Biochemistry 77, 1852-1856; Westhof, E. and Sundaralingham, M. (1980) J. Mol. Biol. 142, 331-361] and constitute the first direct observation of C+.C hemiprotonated pairs in solution. The cross peaks from H1's and more than five distinct AH8's in 500 MHz 1H 2D-NOESY spectra indicate that there are two conformationally different and energetically similar A-tracts. There is good qualitative agreement between NOESY data and two theoretically derived structures in which A-tracts are reverse Watson-Crick and reverse Hoogsteen base-paired, respectively.

Tetraplex formation of d(GGGGGTTTTT): 1H NMR study in solution.

The oligonucleotide d(G5T5) can in principle form a fully matched duplex with G.T pairing and/or a tetraplex. Non-denaturing gel electrophoresis, circular dichroism and NMR experiments show that the tetraplex is exclusively formed by this oligomer in solution. In the presence of its complementary strand d(A5C5) at low temperature, d(G5T5) forms the tetraplex over the normally expected Watson-Crick duplex. However, when d(G5T5) and d(A5C5) are mixed together in equimolar amounts and heated for several minutes at 85 degrees C, and then allowed to cool, the product was essentially the Watson-Crick duplex. The lack of resolution in the 500 MHz 1H NMR spectra and the presence of extensive spin diffusion do not allow us to derive a quantitative structure for the tetraplex from the NMR data. However, we find good qualitative agreement between the NOESY and MINSY data and a theoretically derived stereochemically sound structure in which the G's and T's are part of a parallel tetraplex.