[The effect of corneal biomechanical properties on opaque bubble layer in small incision lenticule extraction (SMILE)]

Objective: To investigate the influence of corneal biomechanical properties on opaque bubble layer (OBL) in small incision lenticule extraction (SMILE). Methods: In this nested case control study, 20 patients (31 eyes) were enrolled in OBL group, while 51 patients (98 eyes) were included in non-OBL group. The parameters were obtained by Pentacam HR and Corvis ST examinations. Independent t test was used to analyze the difference of corneal biomechanical parameters between the two groups and multivariable logistics regression was applied to analysis the influence of corneal biomechanical properties on OBL. Results: This study enrolled 129 eyes in 71 cases including 30 males and 41 females, with a mean age of (22.50±5.18) years old. It has shown that the spherical equivalent (SE) [(-4.64±1.33) and (-5.78±1.61) D], central corneal thickness (CCT) [(572±29) and (550±32)μm], residual stromal thickness (RST)[(356±31) and (325±36 μm)], and lenticule thickness (LT) [(96±23) and (115±25) μm] were significantly different between OBL group and non-OBL group (t=3.58, -3.43, -5.68 and 3.64, respectively, P<0.05). There were significant differences in deflection amplitude at the first applanation and highest concavity (A1 DefA and HC DefA), deflection area at the highest concavity (HC DefArea), maximum deformation amplitude (DAmax), maximum deflection amplitude (DefAmax) and stiff parameter (SP) (108.85±13.77 and 100.19±14.13) between the two groups (t=-2.75, 2.41, 3.62, 4.09, 2.22 and -2.99, respectively, P<0.05). The OR and 95% confidence interval of SP in crude and adjusted logistics models were 1.04, (1.01-1.07) (P=0.005), and 1.01, (1.00-1.05) (P=0.426), respectively. Conclusions: The occurrence of OBL could be influenced by various corneal biomechanical factors. The thicker CCT, thicker RST and the stiffer cornea may increase the risk for the occurrence of OBL. Fully acknowledgement on the relationship between corneal biomechanics and surgical outcomes and evaluation of the occurrence of OBL in SMILE surgery is of great importance for improving the safety and predictability of SMILE. (Chin J Ophthalmol, 2019, 55:115-121).

[Clinical study of suction loss in small incision lenticule extraction]

Objective: To investigate the classification, possible risk factors, managements and clinical outcomes of suction loss in small incision lenticule extraction (SMILE). Methods: In this nested case control study, subjects undergoing SMILE surgery between September 2013 and September 2017 were enrolled in the study. Eyes suffered from suction loss were included in the suction loss group, and eyes without intraoperative complications and operated at the same date were included in the control group. The refraction and visual outcomes were evaluated at preoperative and postoperative 1 day, 1 week, 1, 3 and 6 months. Independent t test and Pearson relation analysis were used for statistical analysis. Results: The study included 206 cases (344 eyes), of which 25 cases (27 eyes) were in suction loss group and 181 cases (317 eyes) were in control group. Suction loss occurred at: (1) scanning posterior surface of lenticule (5, 18.5%); (2) scanning lenticule side cut (1, 3.7%); (3) scanning anterior surface of lenticule (16, 59.3%);(4) scanning incision (5, 18.5%). The main reasons included: (1) abnormal eye movement (14, 51.9%); (2) extra fluid on corneal surface (13, 48.1%). There was significant difference in cap diameter between two groups (t=2.341, P<0.05). At postoperative 3 months, 3.7% (1 eyes) of eyes in cases lost one line; 2.6% (6 eyes) of eyes in controls lost one line. 92.6% (25 eyes) and 91.3% (209 eyes) of eyes had a UCVA of 0.10 LogMAR or better in cases and controls, respectively; 85.2% (31 eyes) and 93.4% (214 eyes) of eyes had a residual SE between±0.50D in cases and controls, respectively. Conclusions: Suction lost during anterior surface of cornea was most common in SMILE surgery. Extra fluid in cornea surface, sudden eye movement of patient and larger corneal cap may result in suction loss. And it may slow the visual recovery, but appropriate and effective managements will be benefited to the final visual outcomes. (Chin J Ophthalmol, 2018, 54: 890-896).

Quantification and antioxidant and anti-HCV activities of the constituents from the inflorescences of Scabiosa comosa and S. tschilliensis

To investigate the bioactive constituents of the inflorescences of Scabiosa comosa and S. tschilliensis, which are used traditionally for liver diseases, we tested the antioxidant activity using 2,2'-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), ferric reducing antioxidant potential (FRAP), and DPPH-ultra high performance liquid chromatography-mass spectrometer (UPLC-MS) assay. In addition, cell-based anti-HCV activity of the major compounds were evaluated. The plant extracts showed strong antioxidant activity. For the first time, 3,4-dicaffeoylquinic acid (DCQA), 3,5-DCQA and 4,5-DCQA were identified from genus Scabiosa. A UPLC-MS method in multiple reaction monitoring (MRM) mode was established to quantify 18 constituents in the inflorescences of Scabiosa. The 3,5-DCQA, chlorogenic acid and some glycosides of luteolin or apigenin were found to be the most abundant constituents. Chlorogenic acid and 3,5-DCQA showed excellent radical scavenging activity and demonstrated anti-HCV activity. These findings provided scientific evidences for the clinic use of this herbal medicine for liver diseases.

Purification and preliminary characterization of new peptide inhibitor of insulin from pork pancreas

A new active peptide was purified from the acid-alcohol extract of pork pancreas. It markedly suppressed the insulin activity detected by either in vivo mouse convulsion assay or in vitro free-fat cell assay. When the extract was subjected to chromatography on a carboxymethylcellulose column, the insulin fraction completely passed through the column, whereas the glucagon fraction was absorbed. The fact that the total apparent biological activity of insulin in the exclusive eluate was higher than in the original extract and the insulin radioimmunoactivity remained unchanged led to the discovery of a potent insulin inhibitor in the extract. The inhibitor was separated from glucagon and insulin in the extract by ion-exchange chromatography on a carboxymethylcellulose column followed by gel filtration on a Bio-Gel P-6 column and finally purified by reverse-phase high-performance liquid chromatography (HPLC) on a C-18 column. The antagonistic effect of this inhibitor on insulin was dose dependent with an ED50 of 2 x 10(-10) M, which was the same level used for insulin in vitro assay (1.7 x 10(-10) M). Amino acid analysis of the inhibitor showed that it was rich in arginine and glycine. It was estimated to be approximately 3000 Mr. The NH2-terminal of the peptide was proved to be blocked because it could not be degraded by Edman degradation. Based on the physicochemical and biochemical characteristics of the inhibitor and compared with other active peptides known to be in the pancreas, the inhibitor is probably a new active peptide that might play an important role in homeostasis of carbohydrate metabolism.

Characterization of a non-hemolytic mutant of Actinobacillus pleuropneumoniae serotype 5: role of the 110 kilodalton hemolysin in virulence and immunoprotection

To determine the role of hemolysin(s) in virulence and immunoprotection, non-hemolytic mutants of Actinobacillus pleuropneumoniae serotype 5, strain J45, were isolated following chemical mutagenesis. One mutant was selected for extensive characterization. Differences in capsule content, or in lipopolysaccharide or membrane protein electrophoretic profiles of the parent and mutant were not detected. A predominant, calcium-inducible protein of 110 kDa was present in culture supernatant of the parent, but absent from the mutant. Two-dimensional (2-D) gel electrophoresis confirmed that the 110 kDa protein was absent in culture supernatant of the mutant, but few, if any, minor differences could be detected in whole-cell proteins between the parent and mutant. The mutant totally lacked extracellular hemolytic and cytotoxic activity. Lysates of whole cells of the mutant contained weak hemolytic activity, and the 110 kDa protein could be detected by immunoblotting. Neutralization titers were negative in pigs immunized with the mutant or purified, denatured hemolysin, although enzyme-immunoassay titers were detected. Four additional independently isolated non-hemolytic mutants were avirulent in pigs and mice at doses greater than 10 times the lethal dose of the parent. Neither pigs nor mice were protected against lethal infection following immunization with the non-hemolytic mutant. We conclude that the 110 kDa hemolysin plays an important role in bacterial virulence and the pathogenesis of pleuropneumonia, and that sufficiently high levels of neutralizing antibodies to the 110 kDa hemolysin may be required for protection of pigs against disease.

Indirect enzyme-linked immunosorbent assay for detection of antibody to a 110,000-molecular-weight hemolysin of Actinobacillus pleuropneumoniae

An indirect enzyme-linked immunosorbent assay (ELISA) was developed to detect swine antibody to a 110,000-molecular-weight hemolysin (110K hemolysin) of Actinobacillus pleuropneumoniae. Affinity-purified rabbit polyclonal or mouse monoclonal immunoglobulin G to the hemolysin of A. pleuropneumoniae serotype 5 strain J45, followed by hemolysin-rich concentrated culture supernatant, was used to bind swine antibody to hemolysin to microdilution plates. Sixty-nine serum samples from swine that were clinically normal, presented with clinical evidence of pleuropneumonia, were experimentally immunized or challenged, or were free of pleuropneumonia were tested, and their ELISA titers were compared with complement fixation (CF) titers. On the basis of serum samples from swine that were clinically normal and negative by CF, an ELISA titer of 1:320 or greater was considered positive. In comparison with CF, the sensitivity of the ELISA was 98.1% and the specificity was 90%. The two samples negative by CF and positive by indirect ELISA were, however, also positive for antibody to serotype 5 capsule by ELISA. Immunization of normal pigs with whole cells or purified hemolysin boosted titers 4- to 128-fold within 4 weeks. Immunoblotting demonstrated that the affinity-purified immunoglobulin G to hemolysin used for capture in the assay recognized only a 110K protein of A. pleuropneumoniae serotypes 1 to 7, although the reactivity was quantitatively variable between serotypes. Therefore, the indirect ELISA is capable of identifying animals infected with or exposed to most, if not all, serotypes of A. pleuropneumoniae. If an indirect ELISA titer of 1:320 or greater is considered positive, the assay can be a valuable diagnostic tool in both clinical and research laboratories.

Photochemistry of hypocrellin A (IV)--Hypocrellin A-sensitized photooxidation of diphenylamine

The photooxidation of diphenylamine is acetonitrile and methanol using Hypocrellin A as sensitizer will be reported in this paper. The products in the two solvents were isolated and identified. The reaction mechanisms were investigated. In acetonitrile, diphenylamine was oxidized by singlet oxygen to form N-phenyl-p-benzoquinonimine. In methanol, N-phenyl-p-benzoquinonimine was produced predominantly through a mechanism irrelevant to singlet oxygen. A small amount of diphenylamine reacted with methanol and singlet oxygen to give a novel product: N-phenyl-2-methoxy-p-benzoquinonimine.