A Cytochrome P450 Enzyme Catalyses Oxetane Ring Formation in Paclitaxel Biosynthesis.

Oxetane synthase (TmCYP1), a novel cytochrome P450 enzyme from Taxus × media cell cultures, has been functionally characterized to efficiently catalyse the formation of the oxetane ring in tetracyclic taxoids. Transient expression of TmCYP1 in Nicotiana benthamiana using 2α,5α,7ß,9α,10ß,13α-hexaacetoxytaxa-4(20),11(12)-diene (1) as a substrate led to the production of a major oxetane derivative, 1ß-dehydroxybaccatin IV (1a), and a minor 4ß,20-epoxide derivative, baccatin I (1b). However, feeding the substrate decinnamoyltaxinine J (2), a 5-deacetylated derivative of 1, yielded only 5α-deacetylbaccatin I (2b), a 4ß,20-epoxide. A possible reaction mechanism was proposed on the basis of substrate-feeding, 2H and 18O isotope labelling experiments, and density functional theory calculations. This reaction could be an intramolecular oxidation-acetoxyl rearrangement and the construction of the oxetane ring may occur through a concerted process; however, the 4ß,20-epoxide might be a shunt product. In this process, the C5-O-acetyl group in substrate is crucial for the oxetane ring formation but not for the 4(20)-epoxy ring formation by TmCYP1. These findings provide a better understanding of the enzymatic formation of the oxetane ring in paclitaxel biosynthesis.

Bridging biological and food monitoring: A colorimetric and fluorescent dual-mode sensor based on N-doped carbon dots for detection of pH and histamine.

Rapid and sensitive monitoring of pH and histamine is crucial for bridging biological and food systems and identifying corresponding abnormal situations. Herein, N-doped carbon dots (CDs) are fabricated by a hydrothermal method employing dipicolinic acid and o-phenylenediamine as precursors. The CDs exhibit colorimetric and fluorescent dual-mode responses to track pH and histamine variations in living cells and food freshness, respectively. The aggregation-induced emission enhancement and intramolecular charge transfer result in a decrease in absorbance and an increase in fluorescence, which become readily apparent as the pH changes from acidic to neutral. This property enables precise differentiation between normal and cancerous cells. Furthermore, given the intrinsic basicity of histamine, pH-responsive CDs are advantageous for additional colorimetric and fluorescent monitoring of histamine in food freshness, achieving linearities of 25-1000 µM and 30-1000 µM, respectively, which are broader than those of alternative nanoprobes. Interestingly, the smartphone-integrated sensing platform can portably and visually evaluate pH and histamine changes due to sensitive color changes. Therefore, the sensor not only establishes a dynamic connection between pH and histamine for the purposes of biological and food monitoring, but also presents a novel approach for developing a multifunctional biosensor that can accomplish environmental monitoring and biosensing simultaneously.

Iris Cerclage To Treat Persistent Mydriasis Following Acute Angle Closure Glaucoma Improves Visual Quality.

PRCIS: We developed a modified iris cerclage technique that improves best corrected visual acuity, pupillary parameters, self-assessed photophobia, and visual function index-14 questionnaire scores in patients with acute primary angle closure and permanent mydriasis after cataract surgery. PURPOSE: To evaluate the efficacy of a modified iris cerclage technique in patients with acute primary angle closure (PAC) and permanent mydriasis after cataract surgery. PATIENTS AND METHODS: 12 eyes of 12 patients with acute PAC and permanent mydriasis at more than 3 months after phacoemulsification combined with intraocular lens (IOL) implantation underwent modified iris cerclage. Best corrected visual acuity (BCVA), intraocular pressure (IOP), pupil diameter, and visual function index-14 (VF-14) questionnaire and self-assessed photophobia scores before surgery and at 1 week, 1 month, and 3 months postoperatively were compared. Further, the postoperative pupil position and morphology and complications were evaluated. RESULTS: BCVA improved from 0.48±0.23 preoperatively to 0.28±0.15, 0.27±0.15, and 0.26±0.14 at 1 week, 1 month, and 3 months postoperatively, respectively (P=0.008). No significant difference was observed between the preoperative and postoperative IOP (P=0.974). Pupil diameter improved from 6.34±0.51 mm preoperatively to 3.59±0.33, 3.59±0.34, and 3.58±0.32 mm at 1 week, 1 month, and 3 months postoperatively, respectively (P<0.001). Self-assessed photophobia scores improved from 3.33±0.78 preoperatively to 0.83±0.72, 0.51±0.15, and 0.45±0.14 at 1 week, 1 month, and 3 months postoperatively, respectively (P<0.001). VF-14 scores improved from 47.6±6.1 points preoperatively to 67.9±6.2, 72.1±6.1, and 73.5±6.0 points at 1 week, 1 month, and 3 months postoperatively, respectively (P<0.001). Postoperatively, all pupils were centered and round. No postoperative complications, such as iris-suture slippage, iridodialysis, or exposure of the IOL's optical zone edge, were observed. CONCLUSION: Modified iris cerclage creates a centered, precisely sized, round pupil. It improves visual quality in patients with acute PAC and permanent mydriasis after cataract surgery.

Chemical constituents from the stems of Dendrobium gratiosissimum and their biological activities.

Eight C6-C3-based bibenzyl derivatives (dengraphenols A-G, K), three mono-bibenzyls (dengraphenols I, L-M), one bis-bibenzyl (dengraphenol H), one oxyneolignane (dengraphenol J), one phenanthrene (dengraphenol N), and one picrotoxane-type sesquiterpene (dengrasusane A) were isolated from the stems of Dendrobium gratiosissimum. The resolution of dengraphenols A-J by chiral HPLC afforded ten pairs of enantiomers [(±)-dengraphenols A-J]. Their structures with absolute configurations were elucidated on the basis of comprehensive spectroscopic analyses, computational calculation methods and single-crystal X-ray diffraction, among which twenty-four [(±)-dengraphenols A-E, (+)-dengraphenol F, (±)-dengraphenols G-J, dengraphenols K-N, dengrasusane A] were undescribed. Ten compounds [(±)-dengraphenol B, (±)-dengraphenols D-E, (±)-dengraphenol H, (-)-dengraphenol I and dengraphenol N)] showed potent cytotoxicity against eight human cancer cell lines (A431, A2780, H460, HCT8, BGC823, SW1990, Daoy, and HGC27) with IC50 values of 3.77-9.75 µM. At a concentration of 10 µM, (-)-dengraphenol C, (±)-dengraphenol F, and (±)-dengraphenol K exhibited remarkable hepatoprotective activity against APAP-induced toxicity with a cell survival rate of 65.8%, 70.6% and 73.5%, respectively; dengraphenol N displayed significant anti-inflammatory effects; and dengraphenol K showed strong inhibitory activity against α-glucosidase with IC50 values of 5.71 µM. These results would provide potential compounds for drug discovery.

Analysis of the therapeutic effect of artificial leather embedding combined with fascial sleeve flap transplantation on chronic wounds of lower limbs with bone and plate exposure.

BACKGROUND: After severe trauma of lower limbs, bone, tendon or plate graft exposure is common. The traditional repair method is to use a variety of skin flap transplantation to cover the exposed part, but the wound often can not heal after operation, or the wound is cracked, ulcer, sinus, bone and steel plate are exposed again after wound healing. The reason for this result is that when the flap is covered, the space around the bone plate is not well closed, forming a dead cavity, blood and exudate accumulation, hematoma formation or infection, and finally the wound ruptures again. In addition, due to the swelling and contracture of the flap after operation, the suture tension between the flap and the receiving area becomes larger, the skin becomes thinner and broken, and then the wound is formed. In order to solve the above problems, we carried out the study of artificial true skin embedding combined with fascial sleeve flap transplantation in the treatment of chronic bone plate exposed wounds of lower limbs. METHODS: In this paper, 11 cases of chronic wounds with bone exposure and skin necrosis after steel plate implantation were selected. First stage is the wound bed preparation including primary wound expansion, removal of necrotic tissue and incision of sinus wall, removal of deep necrotic bone and fibrotic scarred skin on the outer wall of steel plate to normal tissue on the outer edge of the wound, removal of precipitated peptone and purulent fur in the hole, periphery and bone space of the steel plate, and removal of tendon tissue with basal necrosis and disintegration of the wound. After vacuum sealing drainage (VSD) 1-2 weeks, the peritraumatic basal granulation tissue grew well and there was no necrotic tissue in the wound. In the second stage, the exposed bone was covered with artificial dermis, the steel plate hole or the periphery and the basal space were filled, and the exposed steel plate was completely embedded, and then the fascia sleeve flap was transplanted to cover the wound. The sural neurovascular flap was performed in nine cases and the lateral superior malleolar artery perforator flap in two case. RESULTS: The flap survived well in all 11 cases. During the follow-up of 6 months to the removal of the plate, there was no case of rupture, exposure and sinus formation. CONCLUSIONS: Artificial dermal covering combined with fascial sleeve flap transplantation can effectively avoid wound dehiscence or sinus formation caused by foreign body retention, infection and flap contracture. It has good effect in repairing chronic wounds with bone plate exposure after severe trauma of lower limbs.

Combined Transplantation With Human Mesenchymal Stem Cells Improves Retinal Rescue Effect of Human Fetal RPE Cells in Retinal Degeneration Mouse Model.

Purpose: We verified whether fetal RPE (fRPE) cells and mesenchymal stem cells (MSCs) cotransplantation can combine the features of these two cell types and alleviate retinal degeneration in a retinal degenerative disease mouse model. Methods: Tail vein injection of sodium iodate (NaIO3) was conducted to establish the retinal degenerative disease mouse model. MSCs and fRPE cells were transplanted either separately or combined in the subretinal space of retinal degenerative disease animals. ERG, optical coherence tomography, histologic, and immunofluorescence analyses were performed. Furthermore, the expression level of Crx, rhodopsin, Iba1, F4/80, Caspase 3, nerve growth factor, and brain-derived neurotrophic factor were assessed to investigate the mechanisms involved in cell transplantation effects. Results: Cotransplantation of fRPE and MSC cells promoted significant improvements in ERG results and in the survival rate of transplanted cells. In addition, MSC and fRPE cell cotransplantation resulted in an increase in the thickness of the total retina, as well as in the outer and inner nuclear layers. Combined transplantation also upregulated the expression level of Crx and rhodopsin and downregulated caspase 3 expression, highlighting its better photoreceptor rescue effect in relation to the single cell type transplantation. Finally, combined transplantation suppressed the expression of Iba1 and F4/80 factors while increasing the endogenous expression of nerve growth factor and brain-derived nerve growth factor neurotrophic factors. These data suggest that MSC and fRPE cell cotransplantation is able to suppress immunoreactions and promote neurotrophic factor excretion. Conclusions: Combined transplantation of MSCs and fRPE cells results in a better retinal rescue effect than single cell type transplantation in NaIO3-induced retinopathy.

Caffeic acid phenethyl ester attenuates nuclear factor­κB­mediated inflammatory responses in Müller cells and protects against retinal ganglion cell death.

Glaucoma is characterized by the death of retinal ganglion cells (RGCs) and visual field defects, and is a leading cause of blindness worldwide. Caffeic acid phenethyl ester (CAPE), a natural polyphenolic found in propolis from honeybee hives, can inhibit the activation of nuclear factor κ light­chain­enhancer of activated B cells (NF­κB) and has therapeutic potential in inflammatory disease. The present study used a rat model of optic nerve crush (ONC) injury to investigate the effect of CAPE on glaucoma. The death of RGCs at day 14 was significantly reduced in CAPE­treated animals compared with the non­treated group according to Brn3a and TUNEL staining. In addition, CAPE decreased the severity of inflammation in the retina, reflected by the decreased expression of inflammatory cytokines, including interleukin (IL)­8, IL­6, inducible nitric oxide synthase, cycloooxygenase­2, tumor necrosis factor­α and chemokine C­C ligand­2, in CAPE­treated rats. The hypertrophy of astrocytes and Müller cells (gliosis) caused by ONC was also found to be attenuated by CAPE, accompanied by the inhibition of NF­κB signaling. Similarly, in vitro, CAPE suppressed the proliferation and migration of primary astrocytes induced by lipopolysaccharide, as well as the activation of NF­κB. These results suggest that CAPE protected against RGC and attenuated inflammatory responses in a rat model of ONC by suppressing NF­κB activation.

Transurethral procedures in the treatment of benign prostatic hyperplasia: A systematic review and meta-analysis of effectiveness and complications.

BACKGROUND: With the progress of surgical techniques and instruments, various minimally invasive surgical therapies were developed to treat benign prostatic hyperplasisa (BPH). However, the efficacy and safety of different transurethral procedures for the treatment of BPH are still undefined. METHOD: A systematic search was performed for all randomized controlled trials (RCTs), which compared the transurethral procedures for BPH from 1995 to 2016. The clinical baseline characteristics, International Prostate Symptom Score (IPSS), quality of life (QoL), postvoid residual (PVR), maximum flow rate (Qmax), short-term and long-term complications were analyzed using RevMan and ADDIS software. RESULT: Eighty-eight randomly controlled trials and fifteen procedures were included in the network meta-analysis. HoLEP greatly inproved PVR. TmLRP had the best efficacy in improving QoL score. Diode laser vaporization of prostate was superior in improving IPSS and Qmax. Diode laser through vaporization required the shortest time in catheterization, while Nd:YAG was the longest procedure. For the hospitalization time, TUR was the longest and HoLEP was the shortest. TmLRP was related to the lowest postoperative hemoglobin decrease. TmLEP had the least rates of occurrence of hematuria, reoperation and erectile dysfunction. HoLEP was the best choice to reduce the incidence of recatheterization, urinary retention, urinary tract infection, stress urinary incontinence and retrograde ejaculation. The complications such as blood transfusion, urethral stricture, bladder neck contracture were relatively rare in the patients who underwent diode laser vaporization of prostate. CONCLUSION: Compared with other transurethral procedures, thulium, holmium and diode lasers were associated with better efficacy and fewer complications.

Comparison between the retropubic and transobturator approaches in the treatment of female stress urinary incontinence: a systematic review and meta-analysis of effectiveness and complications

Objective This study aimed to compare the effectiveness and complications between the retropubic and transobturator approaches for the treatment of female stress urinary incontinence (SUI) by conducting a systematic review. Materials and Methods We selected all randomized controlled trials (RCTs) that compared retropubic and transobturator sling placements for treatment of SUI. We estimated pooled odds ratios and 95% confidence intervals for intraoperative and postoperative outcomes and complications. Results Six hundred twelve studies that compared retropubic and transobturator approaches to midurethral sling placement were identified, of which 16 were included in our research. Our study was based on results from 2646 women. We performed a subgroup analysis to compare outcomes and complications between the two approaches. The evidence to support the superior approach that leads to better objective/subjective cure rate was insufficient. The transobturator approach was associated with lower risks of bladder perforation (odds ratio (OR) 0.17, 95% confidence interval (CI) 0.09-0.32), retropubic/vaginal hematoma (OR 0.32, 95% CI 0.16-0.63), and long-term voiding dysfunction (OR 0.32, 95% CI 0.17-0.61). However, the risk of thigh/groin pain seemed higher in the transobturator group (OR 2.53, 95% CI 1.72-3.72). We found no statistically significant differences in the risks of other complications between the two approaches. Conclusions This meta-analysis shows analogical objective and subjective cure rates between the retropubic and transobturator approaches to midurethral sling placement. The transobturator approach was associated with lower risks of several complications. However, good-quality studies with long-term follow-ups are warranted for further research. .

[Influence of tetrandrine on SORCIN gene expression in K562/A02 cell line].

This study was aimed to explore the changes of soluble resistance-related calcium binding protein (sorcin) expression in reversion of multidrug resistance of K562/A02 leukemic cell line with different concentrations of tetrandrine (Tet), so as to provide a new theoretic evidence for clinical application of Tet. The inhibition of K562/A02 cell line by daunorubicin (DNR) was assayed by MTT method. The changes of SORCIN gene expression were assayed by RT-PCR. The changes of SORCIN protein expressed were assayed by Western blot. The results showed that Tet could enhance the cytotoxicity of DNR to K562/A02 cells (the IC(50) of DNR + Tet was 11.3+/-0.17 mg/L, 5.15+/-0.10 mg/L, 3.91+/-0.06 mg/L, and 2.52+/-0.04 mg/L, when concentrations of Tet were 0 mg/L, 0.5 mg/L, 1.0 mg/L, and 2.0 mg/L respectively). The gene encoding sorcin was highly expressed in K562/A02 cells, the expression of which was firstly enhanced in Tet concentration 0.5 mg/L, then attenuated in Tet concentration of 1.0, 2.0 mg/L (p<0.05). Sorcin protein expressed lowly in K562 cells and highly in K562/A02 cells, but the expression of SORCIN protein in K562/A02 cells was enhanced in Tet concentration of 0.5 mg/L, then was attenuated in Tet concentration of 1.0, 2.0 mg/L (p<0.05). It is concluded that the effect of Tet on reversal of K562/A02 drug-resistance shows concentration dependence by MTT assay. Tet reverses multidrug-resistance of K562/A02 cells through regulation of expression of SORCIN gene and protein, but not fully correlates to the reversing effect.