Biological concepts for catalysis and reactivity: empowering bioinspiration

Biological systems provide attractive reactivity blueprints for the design of challenging chemical transformations. Emulating the operating mode of natural systems may however not be so easy and direct translation of structural observations does not always afford the anticipated efficiency. Metalloenzymes rely on earth-abundant metals to perform an incredibly wide range of chemical transformations. To do so, enzymes in general have evolved tools and tricks to enable control of such reactivity. The underlying concepts related to these tools are usually well-known to enzymologists and bio(inorganic) chemists but may be a little less familiar to organometallic chemists. So far, the field of bioinspired catalysis has greatly focused on the coordination sphere and electronic effects for the design of functional enzyme models but might benefit from a paradigm shift related to recent findings in biological systems. The goal of this review is to bring these fields closer together as this could likely result in the development of a new generation of highly efficient bioinspired systems. This contribution covers the fields of redox-active ligands, entatic state reactivity, energy conservation through electron bifurcation, and quantum tunneling for C-H activation.

[Correlation between modified Oxford grading scale and pelvic floor surface electromyography in assessment of pelvic floor muscle function in female patients with stress urinary incontinence]

Objective: To investigate the characteristics of modified Oxford grading scale (MOS) and pelvic floor surface electromyography (sEMG) based on Glazer protocol in patients with stress urinary incontinence (SUI), and analyze the correlation between the two methods. Methods: This study was a cross-sectional survey. A total of 212 subjects in May 2019 were enrolled and divided into SUI group (n=61) and non-SUI group (n=151) based on the commonly used 3 incontinence questions (3IQ). MOS test and sEMG parameters were measured by the same rehabilitator. The sEMG parameters included the mean and variation coefficient in the prerest phase, the maximum and relaxation time of 5 rapid contractions, the mean and variability of EMG in 10 s tonic contraction phase, the mean and variability of EMG in 60 s endurance contraction phase, and the mean and variability of EMG in postrest phase. The differences of the above parameters between SUI group and non-SUI group were compared, the logistic regression and Spearman method were used to analyze the correlation between MOS and sEMG parameters. Results: The prevalence of SUI was 28.8%(61/212) in community, body mass index and delivery mode were the risk factors (all P<0.05). The MOS of the SUI group and the non-SUI group were 3 (2,3) and 3 (3,4), respectively, with significant difference (Z=-2.58, P=0.010). Among the sEMG parameters of SUI group and non-SUI group, the maximum values of phasic contractions were 23.12 (13.65, 37.89), 30.68 (20.28, 47.02) μV, the mean of tonic contractions were 14.32 (9.62, 21.49), 17.65 (12.05, 26.35) μV, and the mean of endurance contractions were 12.78(7.88, 18.76), 16.55(11.13, 22.40) μV, respectively, with statistical significance (Z=-2.34, -2.37, -3.20, all P<0.05). The multivariate logistic regression revealed that both the variation coefficient of tonic contractions (OR=157.86, 95%CI: 1.99-12 595.51, P<0.05) and the amplitude of endurance contractions(OR=1.11, 95%CI: 1.03-1.19, P<0.05) were correlated with SUI. The tonic contractions amplitude had the tendency to be related to SUI (OR=0.95, 95%CI: 0.09-1.00, P<0.05). In all subjects, MOS was correlated with the maximum value of rapid contractions, average value of tonic contractions and average value of endurance contractions (r=0.516, 0.503, 0.464, all P<0.05). In SUI group (r=0.510, 0.442, 0.385, all P<0.05), and non-SUI group (r=0.495, 0.524, 0.488, all P<0.05), MOS was correlated with the above parameters. Conclusions: MOS and sEMG based on Glazer protocol indicate that the contractility of pelvic floor muscle decreases in SUI patients. The results of sEMG and MOS are consistent, which can be used for quantitative evaluation of pelvic floor muscle function in SUI patients.

Nicotinamide protects chronic hypoxic myocardial cells through regulating mTOR pathway and inducing autophagy

OBJECTIVE

To determine the protective effect of nicotinamide on chronic hypoxic myocardial cells and its underlying mechanism.

MATERIALS AND METHODS

The H9C2 cell lines were taken as objects of study, and were divided into blank group, hypoxia group and nicotinamide treatment group. The cell viability, apoptosis level, autophagy level and mammalian target of rapamycin (mTOR) pathway activity in each group were detected via Cell Counting Kit-8 (CCK8) assay, Hoechst staining, immunofluorescence staining, Polymerase Chain Reaction (PCR) and Western blotting, respectively.

RESULTS

Nicotinamide could protect the viability of normoxic and chronic hypoxic myocardial cells. Besides, it could also inhibit the expression of caspase3 messenger ribonucleic acid (mRNA) in chronic hypoxic myocardial cells, and reduce the expression of apoptosis-related proteins. Furthermore, it could induce the mRNA expression of autophagy-associated gene 5 (ATG5) and increase the expression of autophagy-related proteins. Further study on the mechanism of nicotinamide showed that nicotinamide could inhibit the activity of the mTOR pathway, thus regulating the autophagy.

CONCLUSIONS

Nicotinamide induces the autophagy of chronic hypoxic myocardial cells by regulating the mTOR pathway, thereby protecting cells from apoptosis.

W-band system-on-chip electron cyclotron emission imaging system on DIII-D

Monolithic, millimeter-wave "system-on-chip" (SoC) technology has been employed in heterodyne receiver integrated circuit radiometers in a newly developed Electron Cyclotron Emission Imaging (ECEI) system on the DIII-D tokamak for 2D electron temperature profile and fluctuation evolution diagnostics. A prototype module operating in the E-band (72 GHz-80 GHz) was first employed in a 2 × 10 element array that demonstrated significant improvements over the previous quasi-optical Schottky diode mixer arrays during the 2018 operational campaign of the DIII-D tokamak. For compatibility with International Thermonuclear Experimental Reactor relevant scenarios on DIII-D, the SoC ECEI system was upgraded with 20 horn-waveguide receiver modules. Each individual module contains a University of California Davis designed W-band (75 GHz-110 GHz) receiver die that integrates a broadband low noise amplifier, a double balanced down-converting mixer, and a ×4 multiplier on the local oscillator (LO) chain. A ×2 multiplier and two IF amplifiers are packaged and selected to further boost the signal strength and downconvert the signal frequency. The upgraded W-band array exhibits >30 dB additional gain and 20× improvement in noise temperature compared with the previous Schottky diode radio frequency mixer input systems; an internal 8 times multiplier chain is used to bring down the LO frequency below 12 GHz, thereby obviating the need for a large aperture for quasi-optical LO coupling and replacing it with coaxial connectors. Horn-waveguide shielding housing avoids out-of-band noise interference on each individual module. The upgraded ECEI system plays an important role for absolute electron temperature evolution and fluctuation measurements for edge and core region transport physics studies.

[Analysis of the relationship between long-term exposure to PM2.5 and sex hormone levels of female sanitation workers in Urumqi]

From June 2017 to June 2018, female sanitation workers engaged in road cleaning in a district of Urumqi City, as well as government and logistics women participating in national health examination in the same community were recruited as particulate matter 2.5 (PM_2.5) exposure group and control group respectively. The contents of follicle stimulating hormone (FSH) and luteinizing hormone (LH) in the PM_2.5 exposed group were lower than those in the control group (all P values < 0.05). Further analysis showed that the content of FSH in the exposure group at the age of 35-39, 40-44 and 45-49 years old was lower than that of the control group (all P values < 0.05). The content of LH in the exposed group at the age of 35-39 and 45-49 years old was lower than that of the control group (all P values < 0.05). The content of FSH in the exposed group with the length of service less than 5, about 5-9 and more than 10 years was lower than that of the control group (all P values < 0.05). The content of LH in the exposed group with the length of service about 5-9 and more than 10 year was lower than that of the control group (all P values < 0.05).

Synthesis and characterization of bulk Nd1-x Sr x NiO2 and Nd1-x Sr x NiO3

The recent reports of superconductivity in Nd_1-x Sr _x NiO₂/SrTiO₃ heterostructures have reinvigorated interest in potential superconductivity of low-oxidation state nickelates. Synthesis of Ni¹⁺-containing compounds is notoriously difficult. In the current work, a combined sol-gel combustion and high-pressure annealing technique was employed to prepare polycrystalline perovskite Nd_1-x Sr _x NiO₃ (x = 0, 0.1, and 0.2). Metal nitrates and metal acetates were used as starting materials, and the latter were found to be superior to the former in terms of safety and reactivity. The Nd_1-x Sr _x NiO₃ compounds were subsequently reduced to Nd_1-x Sr _x NiO₂ using calcium hydride in a sealed, evacuated quartz tube. To understand the synthesis pathway, the evolution from NdNiO₃ to NdNiO₂ was monitored using in situ synchrotron x-ray diffraction during the reduction process. Electrical transport properties were consistent with an insulator-metal transition occurring between x = 0 and 0.1 for Nd_1-x Sr _x NiO₃. Superconductivity was not observed in our bulk samples of Nd_1-x Sr _x NiO₂. Neutron diffraction experiments at 3 and 300 K were performed on Nd_0.9Sr_0.1NiO₂, in which no magnetic Bragg reflections were observed, and the results of structural Rietveld refinement are provided.

An automated controlled-release device for intravaginal hormone delivery

Our objective was to develop and validate an electronically controlled hormone-delivery device for reproductive control of cattle. After development and in vitro testing of a prototype device for intravaginal (IVG) hormone release, we aimed to demonstrate the feasibility of inducing luteal regression by automated treatment with PGF_2α. The IVG device comprises an outer 3D-printed plastic housing, fluid reservoirs connected to delivery pumps and tubing, a programmable circuit board, and a retention mechanism. For in vitro testing, 4 pumps were programmed to release different target volumes (0.1, 0.2, 0.5, 1.0, and 2.0 mL) in 4 replicates (n = 80). A Bland-Altman plot was constructed to assess the magnitude of disagreement between expected and delivered volumes. Observations fell within acceptable limits of agreement (1.96 standard deviations) >95% of the time, indicating overall good agreement (mean difference = -0.005 mL). To assess in vivo performance of the IVG device, lactating Holstein cows with at least 1 corpus luteum ≥15 mm in diameter were randomly allocated to 1 of 3 treatments: (1) IM-PGF (n = 6): two 25-mg intramuscular doses of PGF_2α 24 h apart; (2) DEV-PGF (n = 6): four 25-mg doses of PGF_2α released automatically by the IVG device at 10- or 12-h intervals; and (3) DEV-CTL (n = 4): insertion of an empty IVG device (placebo control). Blood samples were collected at 0, 12, 24, 36, 48, and 72 h after treatment. Data were analyzed by ANOVA with repeated measures. All devices (10/10) remained in situ until removed at 48 h. Progesterone (P4) concentrations from 0 to 72 h were affected by treatment, time, and their interaction. Concentrations of P4 did not differ at time 0 but differed from 24 to 72 h: cows in IM-PGF and DEV-PGF had lesser P4 than cows in DEV-CTL. Conversely, P4 did not differ for IM-PGF and DEV-PGF during the experiment. We conclude that the current IVG hormone-releasing device prototype can be programmed to automatically release PGF_2α for successful induction of luteal regression in lactating dairy cows.

Observation of High-Frequency Transverse Phonons in Metallic Glasses

Using inelastic neutron scattering and molecular dynamics simulations on a model Zr-Cu-Al metallic glass, we show that transverse phonons persist well into the high-frequency regime, and can be detected at large momentum transfer. Furthermore, the apparent peak width of the transverse phonons was found to follow the static structure factor. The one-to-one correspondence, which was demonstrated for both Zr-Cu-Al metallic glass and a three-dimensional Lennard-Jones model glass, suggests a universal correlation between the phonon dynamics and the underlying disordered structure. This remarkable correlation, not found for longitudinal phonons, underscores the key role that transverse phonons hold for understanding the structure-dynamics relationship in disordered materials.

Copper catalysis with redox-active ligands

Copper catalysis finds applications in various synthetic fields by utilizing the ability of copper to sustain mono- and bielectronic elementary steps. Further to the development of well-defined copper complexes with classical ligands such as phosphines and N-heterocyclic carbenes, a new and fast-expanding area of research is exploring the possibility of a complementing metal-centered reactivity with electronic participation by the coordination sphere. To achieve this electronic flexibility, redox-active ligands can be used to engage in a fruitful “electronic dialogue” with the metal center, and provide additional venues for electron transfer. This review aims to present the latest results in the area of copper-based cooperative catalysis with redox-active ligands.

Preparation and Properties of Polyaminosiloxane Modified Polyester Waterborne Polyurethane

In this study, a organosilicon modified waterborne polyurethane (WPU) is synthesized with polyethylene glycol 1,4-butanediol adipate ester diol (PBA) to form the soft segment, dimethylolpropionic acid (DMPA) as the hydrophilic chain extender, and isophorone diisocyanate as the hard segment to synthesize the WPU prepolymer, and aminoethyl aminopropyl dimethicone (AEAPS) as the graft chain extender. The properties of the formed WPU films are then characterized by using Fourier transform infrared spectrometry, thermogravimetric analysis, X-ray diffraction, and dynamic mechanical analysis. It is found that when the amount of AEAPS in the WPU is increased from 0 to 30 wt%, the particle size of the AEAPS modified WPU emulsion is increased from 84.8 nm to 271.9 nm and maintained high centrifugal stability. Moreover, the water absorption of the WPU film is reduced from 43.4% to 24.1%, and the hardness is enhanced from 3H to 5H, while the glass-transition temperature (Tg) of the soft segment of the modified WPU shifts from -37.4 °C to -44.3 °C, and the Tg of the hard segment shifts from 73.6 °C to 118.1 °C. Therefore, the overall performance of AEAPS modified WPU is improved.

Clinical effectiveness of 3 days preoperative treatment with recombinant human erythropoietin in total knee arthroplasty surgery: a clinical trial

AIMS

The purpose of study is to evaluate the effect and complication of preoperative short-term daily recombinant human erythropoietin (rhEPO) treatment for blood-saving in patients undergoing unilateral primary total knee arthroplasty (TKA).

METHODS

This three-arm randomized clinical trial compared three different rhEPO-based treatment protocols for unilateral primary TKA. Group A: application of daily doses of rhEPO combined with iron supplement starting 3 days before surgery; Group B: application of daily doses of rhEPO combined with iron supplement starting the day of surgery; Group C: iron supplement alone. Perioperative hemoglobin (Hb) level gaps, total perioperative blood loss, reticulocyte levels and treatment-related complications were studied.

RESULTS

A total of 102 patients were included (35, 35 and 32 patients in Groups A, B and C, respectively). Total blood loss (TBL) in Groups A, B and C was 490.84, 806.76 and 924.21 ml, respectively. Patients in Group A had a significant lower TBL than Groups B and C (A vs. B: P = 0.010; A vs. C: P < 0.001). There was no difference as for TBL between Groups B and C (P = 0.377). Group A patients had significant smaller Hb decline than Group C on the third and fifth postoperative day (P = 0.049, P = 0.037), as well as than Group B on the fifth postoperative day (P = 0.048). There was no difference as for Hb decline between Groups B and C. No difference was shown in levels of inflammatory biomarkers or blood-saving protocol-related complications among three groups.

CONCLUSIONS

Daily dose of rhEPO combined with iron supplement administered 3 days before TKA procedures could significantly decrease perioperative blood loss and improve postoperative Hb levels, without significantly elevating risks of complication, when compared with admission of rhEPO on the day of surgery and iron supplement alone. Preoperative daily rhEPO treatment could be a more effective blood-saving protocol in TKA procedures.

Optimizing Group Transfer Catalysis by Copper Complex with Redox-Active Ligand in an Entatic State

Metalloenzymes use earth-abundant non-noble metals to perform high-fidelity transformations in the biological world. To ensure chemical efficiency, metalloenzymes have acquired evolutionary reactivity-enhancing tools. Among these, the entatic state model states that a strongly distorted geometry induced by ligands around a metal center gives rise to an energized structure called entatic state, strongly improving the reactivity. However, the original definition refers both to the transfer of electrons or chemical groups, whereas the chemical application of this concept in synthetic systems has mostly focused on electron transfer, therefore eluding chemical transformations. Here we report that a highly strained redox-active ligand enables a copper complex to perform catalytic nitrogen- and carbon-group transfer in as fast as 2 min, thus exhibiting a strong increase in reactivity compared with its unstrained analogue. This report combines two reactivity-enhancing features from metalloenzymes, entasis and redox cofactors, applied to group-transfer catalysis.

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We design a catalyst interfacing two reactivity-enhancing tools from metalloenzymes

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This work merges redox-active cofactors and entatic state reactivity

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The modifications in the coordination sphere lead to enhanced catalytic behavior

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These results open perspectives in bioinspired catalysis and group-transfer reactions

Complement C3 overexpression activates JAK2/STAT3 pathway and correlates with gastric cancer progression

Background

Localized C3 deposition is a well-known factor of inflammation. However, its role in oncoprogression of gastric cancer (GC) remains obscured. This study aims to explore the prognostic value of C3 deposition and to elucidate the mechanism of C3-related oncoprogression for GC.

Methods

From August to December 2013, 106 GC patients were prospectively included. The regional expression of C3 and other effectors in gastric tissues were detected by WB, IHC, qRT-PCR and other tests. The correlation of localized C3 deposition and oncologic outcomes was determined by 5-year survival significance. Human GC and normal epithelial cell lines were employed to detect a relationship between C3 and STAT3 signaling pathway in vitro experiments.

Results

C3 and C3a expression were markedly enhanced in GC tissues at both mRNA and protein levels compared with those in paired nontumorous tissues. According to IHC C3 score, 65 (61.3%) and 41 (38.7%) patients had high and low C3 deposition, respectively. C3 deposition was negatively correlated with plasma levels of C3 and C3a (both P < 0.001) and positively correlated with pathological T and TNM stages (both P < 0.001). High C3 deposition was identified as an independent prognostic factor of poor 5-year overall survival (P = 0.045). In vitro C3 administration remarkably enhanced p-JAK2/p-STAT3 expression in GC cell lines but caused a reduction of such activation when pre-incubated with a C3 blocker. Importantly, C3 failed to activate such signaling in cells pre-treated with a JAK2 inhibitor.

Conclusions

Localized C3 deposition in the tumor microenvironment is a relevant immune signature for predicting prognosis of GC. It may aberrantly activate JAK2/STAT3 pathway allowing oncoprogression.

Trial registration

ClinicalTrials.gov, NCT02425930, Registered 1st August 2013.

Antisymmetric linear magnetoresistance and the planar Hall effect

The phenomena of antisymmetric magnetoresistance and the planar Hall effect are deeply entwined with ferromagnetism. The intrinsic magnetization of the ordered state permits these unusual and rarely observed manifestations of Onsager’s theorem when time reversal symmetry is broken at zero applied field. Here we study two classes of ferromagnetic materials, rare-earth magnets with high intrinsic coercivity and antiferromagnetic pyrochlores with strongly-pinned ferromagnetic domain walls, which both exhibit antisymmetric magnetoresistive behavior. By mapping out the peculiar angular variation of the antisymmetric galvanomagnetic response with respect to the relative alignments of the magnetization, magnetic field, and electrical current, we experimentally distinguish two distinct underlying microscopic mechanisms: namely, spin-dependent scattering of a Zeeman-shifted Fermi surface and anomalous electron velocities. Our work demonstrates that the anomalous electron velocity physics typically associated with the anomalous Hall effect is prevalent beyond the ρ_xy(H_z) channel, and should be understood as a part of the general galvanomagnetic behavior.

Magnetoresitance (MR) is a tool to study electronic transport and spin order in metals. Here, the authors demonstrate two different microscopic origins of antisymmetric linear MR from both Zeeman-split Fermi surface and anomalous electron velocity.

GluR1 protects hypoxic ischemic brain damage via activating Akt signaling pathway in neonatal rats

OBJECTIVE

To investigate the role of glutamic acid receptor 1 (GluR1) in hypoxic-ischemic brain damage (HIBD) in neonatal rats and its underlying mechanism.

MATERIALS AND METHODS

7-day-old neonatal rats received right common carotid artery (CCA) ligation for the establishment of HIBD. After the operation, rats were sacrificed at different time points (0, 4, 6, 12, 24, 48, and 72 h), respectively. Meanwhile, rats in Sham group underwent similar procedures without ligation. Lentivirus-GLUR1-shRNA (LV-GLUR1 shRNA group) was constructed and then transfected into the right lateral ventricles of rats to inhibit GluR1 in vivo. Rats received LV-control injection were selected in the control group (LV-control group). After injection of Lentivirus-GLUR1-shRNA, CCA ligation was performed in rats for HIBD construction. Western blot was performed to detect the protein levels of GLUR1, Akt, p-Akt, and vascular endothelial growth factor (VEGF) in brain tissues. Cell apoptosis was measured by TUNEL staining assay.

RESULTS

After hypoxic ischemia (HI), GLUR1 expression increased gradually and reached a peak at 24 h. Meanwhile, p-Akt expression increased immediately and then gradually decreased. 24 h later, p-Akt expression increased again and peaked at 48 h. VEGF expression increased at 4 h after HI and reached a peak at 12 h. The expression levels of GLUR1, p-Akt, and VEGF in the brain tissues derived from rats transfected with LV-GLUR1 shRNA significantly decreased at both 4 h and 24 h after HI. In addition, results indicated that cell apoptosis was enhanced after LV-GLUR1 shRNA administration, suggesting the role of GLUR1 in protecting against HIBD.

CONCLUSIONS

GLUR1 exhibits a remarkable protective role in HIBD, which may be related to the activation of the Akt signaling pathway and the upregulation of VEGF after HI.

HOTAIR promotes inflammatory response after acute myocardium infarction by upregulating RAGE

OBJECTIVE

The aim of this study was to explore the role of HOTAIR in inflammatory response after acute myocardium infarction (AMI) and to investigate its underlying mechanism.

MATERIALS AND METHODS

The AMI model was first constructed in rats, and heart tissues were harvested. Expression levels of HOTAIR and receptor of advanced glycation end-products (RAGE) in rat heart were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The protein expression level of pEKR in rat heart was detected by Western blot. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in rats were determined by enzyme-linked immunosorbent assay (ELISA). The hypoxia-induced H9C2 cells were used to construct the MI model in vitro. Meanwhile, the expression levels of HOTAIR and RAGE in H9C2 cells were detected. The levels of TNF-α and IL-6 in the culture medium were determined by ELISA. Rescue experiments were conducted by co-transfecting pcDNA-HOTAIR and si-RAGE in H9C2 cells. Subsequently, the levels of pERK, TNF-α, and IL-6 were detected.

RESULTS

The mRNA expression levels of HOTAIR and RAGE in the AMI group were significantly higher than those of the control group. Western blot showed remarkably higher protein levels of RAGE and pERK in AMI rats when compared with those of controls. Similarly, results of ELISA indicated that the levels of TNF-α and IL-6 in AMI rats were significantly higher than those of controls. Meanwhile, overexpression of HOTAIR in H9C2 cells remarkably elevated the expression levels of HOTAIR and RAGE. In addition, upregulated pERK, TNF-α, and IL-6 were observed in H9C2 cells overexpressing HOTAIR, which could be reversed by RAGE knockdown.

CONCLUSIONS

HOTAIR promotes inflammatory response after AMI by upregulating RAGE expression.

Effect of miR-497 on myocardial cell apoptosis in rats with myocardial ischemia/reperfusion through the MAPK/ERK signaling pathway

OBJECTIVE

The aim of this study was to investigate the effect of micro ribonucleic acid (miR)-497 on myocardial cell apoptosis in rats with myocardial ischemia/reperfusion (I/R) through the mitogen-activated protein kinase (MAPK)/extracellular regulated protein kinase (ERK) signaling pathway.

MATERIALS AND METHODS

A rat model of myocardial I/R was established, myocardial cells were extracted, and miR-497 was inhibited by inhibitors and overexpressed using miRNA mimics. The cell apoptosis rate was detected by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The interaction between miR-497 and ERK was determined by dual-luciferase reporter gene assay. The change in the protein level was measured via Western blotting (WB).

RESULTS

Up-regulation of miR-497 promoted myocardial cell apoptosis, and the 3'-untranslated region (3'-UTR) of ERK was highly conserved to combine with miR-497. The luciferase reporter gene assay showed that the transfection of miR-497 could significantly inhibit the relative luciferase activity in cells.

CONCLUSIONS

MiR-497 overexpression significantly down-regulated the ERK expression at messenger RNA (mRNA) and protein levels in cells. MiR-497 plays an important role in regulating I/R injury-induced myocardial cell apoptosis by targeting the ERK-induced apoptosis pathway.

[Application of adrenalin saline local injection in endoscopic type Ⅰ tympanoplasty]

Objective: To evaluate the effect of adrenalin saline local injection on reducing bleeding in endoscopic typeⅠtympanoplasty. Method: A total of 50 patients underwent endoscopic type Ⅰtympanoplasty were prospectively enrolled and were randomly divided into 2 groups. Patients in research group were locally injected 5 ml adrenalin saline with a concentration of 1∶200 000, 15 minutes before operation. And the control group were not injected. Grafts acceptance rates, operation time, blood loss, pre- and pro- operative audiograms were compared between the two groups. Result: Compared with control group, the operative time and blood loss was less in research group. These differences were statistically significant(P<0.05). There was no significant difference in grafts acceptance rate between two groups (P>0.05). After surgery, mean air conduction threshold was increased and the air-bone gaps was decreased in both groups,and no statistical significant deference was found between the two groups(P>0.05). Conclusion: Before endoscopic type I tympanoplasty, adrenalin saline local injection can reduce blood loss significantly. This allows better operative view and experience for surgeons and less surgery damage to patients.