[Research progress of idiopathic tinnitus]

SummaryIdiopathic tinnitus is a spontancous sense of hearing under neither external acoustic or electric stimuli,and is one of the common symptoms of otorhinolaryngology. At present，the clinical stages and classification of tinnitus vary among different countries. The examination of tinnitus is also multifaceted, including audiology, imaging, psychology and other tests to find tinnitus for the purpose. There are many treatments for tinnitus, including etiological treatment, counseling, cognitive behavioral therapy, tinnitus masking therapy, tinnitus therapy, hearing aids, cochlear implants, drug therapy, repetitive transcranial magnetic stimulation, electrical stimulation and so on.The above treatment methods have not reached a consensus on the efficacy of tinnitus. In recent years, some technology innovations based on sound have produced personalized treatment schemes for different types of tinnitus,which will inevitably become a hot topic in future research.

Totally robotic modified complete mesocolic excision and central vascular ligation for right-sided colon cancer: technical feasibility and mid-term oncologic outcomes

BACKGROUND

Recently, an operative strategy involving complete mesocolic excision (CME) and central vascular ligation (CVL) for colonic cancer has been introduced. We aimed to describe our initial experience and assess the long-term outcomes of robotic modified CME (mCME) and CVL (mCME+CVL) for right-sided colon cancer.

METHODS

Of the 677 patients with histologically confirmed, right-sided colon adenocarcinoma who underwent curative mCME+CVL between February 2008 and October 2016, 43 who were treated entirely using the robotic approach were included in this retrospective study. Survival rates were determined using the Kaplan-Meier method, and P values of < 0.05 indicated statistically significant differences.

RESULTS

The total operation and docking times were 293 (180-644) min and 5 (3-19) min, respectively, with an estimated blood loss of 50 (10-400) mL. The time to soft diet was 4 (1-16) days and the length of hospitalization was 8 (4-48) days. Based on the Clavien-Dindo classification, grade I, II, IIIa, IIIb, and IV complications were noted in 3 (7.0%), 5 (11.7%), 2 (4.7%), 1 (2.3%), and 0 (0%) patients, respectively. The proximal and distal resection margins were 14 (4-54) and 19 (4-48) cm, respectively, and 29 (6-157) lymph nodes were harvested per patient. The patients were followed-up for a median of 55 (2-109) months, during which the overall survival rate, median disease-free period, disease-free survival rate, and tumor recurrence rate were 93.6%, 38 (2-109) months, 81.1%, and 16.3% (7 patients), respectively.

CONCLUSIONS

Robotic mCME and CVL for right-sided colon cancer was feasible and safe. It can be added to the surgeon's toolbox as an optional strategy for the management of colon cancer patients.

[Clipping for large paraclinoid internal carotid artery aneurysms by non-fluoroscopic occlusion via a micro-bone window frontolateral approach]

Objective: To evaluate the clinical value and outcomes of technical improvement of hybrid operatical clipping for large paraclinoid internal carotid artery aneurysms. Methods: A review was conducted on 18 cases of large paraclinoid internal carotid artery aneurysm which were clipped by balloon non-fluoroscopic occlusion of the parent artery via a micro-bone window frontolateral approach in hybrid operating room at Neurosurgery Department of Tianjin Medical University General Hospital from June 2014 to December 2017. There were 8 males and 10 females with age of (63±4) years. There were 6 cases of unruptured aneurysm and 12 cases of ruptured aneurysm of subarachnoid hemorrhage (6 cases of grade Ⅱ, 4 cases of grade Ⅲ and 2 cases of grade Ⅳ in Hunt-Hess classification). Frontolateral approach incision (average length of about 5 cm) and bone window about 3 cm×3 cm were performed. No incision of the neck was needed to expose the internal carotid artery for temporary occlusion. In the operation, the balloon was slowly pushed to the preset position of the internal carotid artery under non-fluoroscopy. The balloon was expanded to block the blood flow of internal carotid artery. Then aneurysm was clipped. The balloon was loosened and retraced to the guiding catheter after clipping. The clipping condition was examined by cerebral angiography. If there was residual aneurysm neck or stenosis of the parent artery, the balloon was pushed under non-fluoroscopy again to temporary occlusion and the clip was adjusted until the aneurysm neck was clamped satisfactorily. Results: Eighteen aneurysms were successfully clipped in hybrid operating room. Fourteen aneurysms showed complete occlusion of the aneurysm neck and no stenosis of the parent artery. Four cases showed residual aneurysm neck after clipping by intraoperative angiography, then aneurysms were clipped satisfy by adjusting the aneurysm clip. The patients were followed up for 3 months to 1 year. Ten patients recovered well (modifed Rankin score (mRS): 0), and 3 patients had no obvious disability (mRS: 1). Two patients with Hunt-Hess grade Ⅲ were slightly disabled (mRS: 2). 1 patients with Hunt-Hess grade Ⅲ were moderately disabled (mRS: 3). 1 patients with Hunt-Hess grade Ⅳ were severely disabled (mRS: 4). One elderly patients with Hunt-Hess grade Ⅳ were seriously disabled (mRS: 5). Conclusions: Application of balloon non-fluoroscopic occlusion clipping for large paraclinoid internal carotid artery aneurysm via a micro-bone window frontolateral approach is safe, effective and minimally invasive.

[Influence of fracture resistance of prosthesis with different thickness of ferrule restored with fiber post and resin core and crown]

Objective: To evaluate the influence of fracture resistance of endodontically treated teeth with different thickness of ferrule by mechanical fatigue test and static loading test, and so as to provide a reference for the clinical treatment planning. Methods: Fifty bovine incisors were divided into 5 groups by random number table method (n=10). Group A was the control group in which the incisors were prepared without a ferrule design (0 mm). The other four groups (B, C, D, E) were experimental groups, and the thickness of the dentin ferrule prepared for specimens in each group was 0.5, 1.0, 1.5, and 2.0 mm. The height of ferrules in all the specimens was 2 mm. Cyclic fatigue loading (2.33 Hz, 50 N) was applied on each specimen until either the specimen was dislodged/fractured or the 300 000 cycles were finished. After fatigue loading, the mode of failure was observed. Those intact specimen after fatigue loading were tested under a gradually increasing force using a universal testing machine (0.05 mm/min) until fracture occurred. The forces required to fracture and failure model was recorded. Results: The results of cyclic loading tests showed that: all specimens survived the 300 000 cycles of intermittent loading. The results of static loading tests showed that: the fracture force of A, B, C, D and E groups respectively were (226.4±67.7), (369.7±34.5), (400.7±48.2), (528.1±56.3), and (555.4±98.5) N (F=15.227, P=0.000). There was a significant difference in fracture resistance between group A and the other four groups, and between group B, C and group D, E (P<0.05). No statistical difference were found in fracture resistance among the other groups (P>0.05). There was strong correlation between the thickness of ferrule and the fracture force by Pearson correlation analysis (r=0.973, P=0.002). Conclusions: Within the limitations of this study, the following conclusions can be drawn: The different thickness of ferrule can influence the fracture resistance of the teeth, and when the height of the ferrule is 2.0 mm, the fracture force increased significantly with an increasing ferrule thickness.

Critical and Challenging Issues in the Surgical Management of Low-Lying Rectal Cancer

Despite innovative advancements, the management of distally located rectal cancer (RC) remains a formidable endeavor. The critical location of the tumor predisposes it to a circumferential resection margin that tends to involve the sphincters and surrounding organs, pelvic lymph node metastasis, and anastomotic complications. In this regard, colorectal surgeons should be aware of issues beyond the performance of total mesorectal excision (TME). For decades, abdominoperineal resection had been the standard of care for low-lying RC; however, its association with high rates of tumor recurrence, tumor perforation, and poorer survival has stimulated the development of novel surgical techniques and modifications, such as extralevator abdominoperineal excision. Similarly, difficult dissections and poor visualization, especially in obese patients with low-lying tumors, have led to the development of transanal TME or the "bottom-to-up" approach. Additionally, while neoadjuvant chemoradiotherapy has allowed for the execution of more sphincter-saving procedures without oncologic compromise, functional outcomes remain an issue. Nevertheless, neoadjuvant treatment can lead to significant tumor regression and complete pathological response, permitting the utilization of organ-preserving strategies. At present, an East and West dualism pervades the management of lateral lymph node metastasis, thereby calling for a more global and united approach. Moreover, with the increasing importance of quality of life, a tailored, individualized treatment approach is of utmost importance when taking into account oncologic and anticipated functional outcomes.

MRI-based EMVI positivity predicts systemic recurrence in rectal cancer patients with a good tumor response to chemoradiotherapy followed by surgery

BACKGROUND

This study aimed to determine the prognostic value of baseline magnetic resonance imaging-based extramural vascular invasion status (EMVI) among rectal cancer patients with a good tumor response to standard chemoradiotherapy followed by surgery.

METHODS

A total of 359 patients with ypT0-2/N0 disease from The Yonsei Multicenter Colorectal Cancer Electronic Database were retrospectively included between January 2000 and December 2014. Magnetic resonance images and medical records were reviewed to investigate risk factors for tumor recurrence.

RESULTS

When we compared patients without and with EMVI, significant differences were observed in the 5-year disease-free survival rate (DFS) (80.8% vs 57.8%, P = 0.005) and in the 5-year systemic recurrence-free survival rate (SRFS) (86.9% vs 64.3%, P = 0.007). In the multivariate analysis, both mrEMVI and APR independently predicted overall DFS (APR; HR 2.088, 95% CI: 1.082-4.031, P = 0.028, mrEMVI; HR: 2.729, 95% CI: 1.230-6.058, P = 0.014). mrEMVI was only independent prognostic factor for systemic recurrence with statistical significance (HR: 3.321, 95% CI: 1.185-9.309, P = 0.022).

CONCLUSION

Even in rectal cancer patients with a good response to chemoradiotherapy followed by curative surgery, extramural vascular invasion and APR may predict poor disease-free survival outcomes. Intensified treatment strategy should be considered.

Difference between right-sided and left-sided colorectal cancers: from embryology to molecular subtype

INTRODUCTION

Colorectal cancer is one of the most common malignancies in the world, and it exhibits differences in incidence, pathogenesis, molecular pathways, and outcome depending on the location of the tumor. Differences in the microbiome, clinical characteristics, and chromosomal and molecular characteristics have been reported between the right and left side of the colon. Areas covered: This review focuses on the latest developments in epidemiological and chromosomal and molecular studies, which have enhanced our understanding on the underlying genetic and immunological differences between the right-sided colon and the left-sided colorectum in metastatic colorectal cancer. Expert commentary: The numerous findings regarding differences between right- and left-sided colon cancers should have an impact on colorectal cancer screening and therapy. The location of the colorectal cancer should be considered before group stratification into genetic, clinical, and especially chemotherapy trials. A more tailored approach to colon cancer treatment would be highly desirable if future trials further support the hypothesis of two distinct tumor entities.

Sol-Gel Derived Antibacterial Ag-Containing ZnO Films on Biomedical Titanium

ZnO and Ag-containing ZnO (ZnO/Ag) films with the Ag/Zn molar ratio of 3.3 and 9.1%, respectively were sol-gel coated on biomedical titanium for antibacterial and bioactive surface modification. X-ray diffraction analysis indicates that ZnO peaks increase with the calcination temperature of the samples. Scanning electron microscopy and energy dispersive of X-ray analyses reveal Ag-rich white particles (300~750 nm) on ZnO/Ag samples that were calcined at 400 °C. X-ray photoelectron spectroscopy analysis of ZnO/Ag samples shows that Zn and O exist as ZnO and Ag presents in metallic state. The coating samples exhibit similar UV light-induced hydrophilic conversion behavior. Potentiodynamic polarization test in a Ca-free Hank's balanced solution demonstrates better corrosion resistance of the coating samples compared with the polished sample. In the in vitro bioactivity test using the simulated body fluid, a layer of apatite is gradually deposited on the surface of sample ZnO/9Ag after 12 days of soaking. The MTT assay test shows that ZnO and ZnO/Ag films have weak compatibility with the L929 cells. The antibacterial test against E. Coli by the disk diffusion assay reveals that antibacterial activity of the coating samples increases with silver content of the films.

A Granular Cell Tumor of the Rectum: A Case Report and Review of the Literature

A granular cell tumor (GCT) is an uncommon mesenchymal lesion that rarely occurs in the colon and the rectum. We describe the case of 51-year-old man with a 2-cm-sized rectal GCT 10 cm above the anal verge that was incidentally detected after a screening colonoscopy. Preoperative radiologic studies demonstrated a suspicious submucosal rectal mass with mesorectal fat infiltration, but without circumferential resection margin threatening, extramural vessel invasion, and regional lymph-node enlargement. The tumor was resected by using a transanal endoscopic operation (TEO) without immediate postoperative complications. The final pathology revealed that the tumor consisted of a GCT that had invaded the subserosa with clear margins. It had no other risk factors for malignancy according to Fanburg-Smith criteria. We systematically reviewed the English literature by using PubMed and Google Scholar. This report may be the first documented case in the literature to describe a TEO for a GCT that had invaded the subserosa in the rectum.

Effective Dose of Remifentanil for Control of Haemodynamic Response to Insertion of the Streamlined Liner of the Pharyngeal Airway

Objective

To determine the dose of remifentanil needed to achieve successful insertion of the Streamlined Liner of the Pharyngeal Airway (SLIPA™) without the development of hypertension in 95% of the patients.

Design

Randomised controlled trial.

Setting

operating theatre of a university hospital

Methods

A total of 100 ASA I or II patients requiring SLIPA insertion were randomly assigned to receive normal saline (Group C) or one of the four different doses (0.5 µg/kg [Group R0.5], 1.0 µg/kg [Group R1], 1.5 µg/kg [Group R1.5] or 2.0 µg/kg [Group R2]) of remifentanil. Arterial blood pressure and heart rate were recorded at preanesthetic baseline, preinserton, and every one minute during the initial 3 minutes period after insertion.

Results

A Probit model of remifentanil concentration was predictive of successful insertion of SLIPA without the development of hypertension. The ED95 of remifentanil needed to suppress haemodynamic response from SLIPA insertion was 1.39 µg/kg (95% confidence interval, 1.06-2.61 µg/kg).

Conclusions

A single administration of remifentanil can effectively suppress haemodynamic changes due to the insertion of SLIPA.

Streamlined Liner of the Pharynx Airway: Randomised Comparison of Size Selection Strategies with Regard to Patient Height versus Thyroid Cartilage Width

Introduction

Streamlined Liner of the Pharynx Airway (SLIPA) is a disposable supraglottic airway. There are two strategies to select the size of SLIPA: by height and width of thyroid cartilage. This study compared the utility of the two strategies in selecting the optimal size.

Methods

One hundred forty-two patients were randomly divided into two groups with size selection by height (H) and the maximal width of the thyroid cartilage (T). The SLIPA size was selected by height in group H, and by the width of thyroid cartilage in group T. After inserting SLIPA, the investigator made note of the oropharyngeal leakage pressure (OLP) and the degree of insertion difficulty. We set the OLP as a primary outcome. In cases of an OLP <15 cmH2O, the investigator manipulated the apparatus to try to reposition it. If air still leaked, another attempt was made using a SLIPA one size larger until an OLP >15 cmH2O was achieved in up to three attempts. After insertion, the investigator measured the inspiratory and expiratory tidal volume. Post-operatively, the presence of blood or regurgitated fluid on the device was evaluated.

Results

OLP for group T was higher than that of group H (p=0.009). The need for manipulation and the leak fraction was higher in group H than in group T (p=0.008 and 0.034, respectively). The degree of insertion difficulty, number of trials and incidence of blood and regurgitated fluid on the device were similar between the two groups.

Conclusions

Both the width and height of thyroid cartilage can be used for selecting the optimal SLIPA size. (Hong Kong j.emerg.med. 2015;22:303-311)

Repeated Measurement of Fractional Exhaled Nitric Oxide Is Not Essential for Asthma Screening

BACKGROUND AND OBJETIVE

Older guidelines recommend that fractional exhaled nitric oxide (FeNO) should be checked more than twice during the same session to confirm an asthma diagnosis. Recent studies show the excellent reproducibility of FeNO measurements. Objetive: We aimed to determine whether repeated FeNO measurements during the same session are necessary for asthma screening.

MATERIAL AND METHODS

We retrospectively reviewed the electronic medical records of adult outpatients who visited the respiratory medicine department for diagnosis of asthma and assessed FeNO measurements obtained from June 2016 to July 2017.

RESULTS

Of the 132 patients enrolled, 79 (59.8%) were diagnosed with asthma. Repeated FeNO measurements taken during the same session showed high reproducibility (intraclass correlation coefficient >0.9; P<.001) and a strong correlation (Pearson coefficient >0.9; P<.001), although reproducibility and correlation were slightly weaker in patients with low FeNO values. The value of repeated measurement was not significant; however, the second FeNO measurement was significantly higher than the first measurement in patients with the worst and best lung function. The predictive power of the first measurement of FeNO (sensitivity, 80.5%; specificity, 85.1%) was not inferior to the second (sensitivity, 76.6%; specificity 85.1%). The same was true of the geometric mean of the two.

CONCLUSIONS

Repeated FeNO measurement during the same session is not essential for asthma screening in cases where the first acceptable FeNO measurement is performed using the proper method.

Acute hypoxic stress: Effect on blood parameters, antioxidant enzymes, and expression of HIF-1alpha and GLUT-1 genes in largemouth bass (Micropterus salmoides)

Dissolved oxygen (DO) plays a crucial role in survival, growth, and normal physiological functions of aquatic organisms. Nevertheless, the mechanisms involved in hypoxic stress and adaptation have not been fully elucidated in Largemouth bass (Micropterus salmoides). To reveal the effect of acute hypoxia on Largemouth bass, we simulated acute hypoxia (DO: 1.2 ± 0.2 mg/L) in the laboratory and analyzed physiological parameters (RBCs, Hb, SOD, CAT, NA⁺/K⁺-ATPase, GPx, and MDA) and gene expression (HIF-1alpha and GLUT-1) in Largemouth bass exposed to various durations of acute hypoxia (0, 1, 2, 4, 8, 12, and 24 h). Our results indicated that acute hypoxic exposure significantly increased RBCs but decreased Hb. In addition, antioxidant enzyme activity was enhanced significantly in the liver and muscles at the initial stage of acute hypoxic exposure, but decreased significantly in gills during the entire process of hypoxic exposure. Furthermore, the expression levels of HIF-1alpha and GLUT-1 mRNA were significantly up-regulated in Largemouth bass under acute hypoxic exposure. In conclusion, our study provides a valuable basis for further elucidation of hypoxic adaptation and facilitates husbandry for an economically valuable species.

Intraoperative colonoscopy for the assessment and prevention of anastomotic leakage in low anterior resection for rectal cancer

PURPOSE

Anastomotic leakage (AL) after stapled anastomosis in rectal cancer surgery is a major concern. Various types of intraoperative anastomotic air leakage tests (ALTs) have been proposed to reduce AL. This study aimed to evaluate the impact of intraoperative colonoscopy (IOC) as an intraoperative ALT in low anterior resection for rectal cancer.

METHODS

A total of 1266 patients were retrospectively reviewed. Among them, 215 patients who underwent IOC as an ALT in rectal cancer surgery were identified. IOC was performed after anastomosis to visualize the anastomosis line and to perform an ALT by insufflating the neorectum. Propensity score matching was used to match this group at a 1:1 ratio with 215 patients who underwent ALT with a 250-mL bulb irrigation syringe. Anastomotic defects that were found intraoperatively were resolved either by means of primary repair of the anastomotic defect, if possible, or by performing a preventive diverting ileostomy.

RESULTS

The patient characteristics, pathologic outcomes, and operation details showed no significant difference between the two groups. Comparison of the AL rate showed a significant difference between the groups (IOC group without intraoperative leaks vs. non-IOC group without intraoperative leaks 4.3 vs. 11.7%, P = 0.007). The incidence of preventive diverting ileostomy because of a positive ALT was significantly higher in the IOC group than in the non-IOC group (10 vs. 2 cases, P = 0.036).

CONCLUSION

IOC can be a valuable method for the assessment of stapled anastomosis and has the additional benefit of directly visualizing the anastomosis line.

Proximal femoral nail antirotation internal fixation in treating intertrochanteric femoral fractures of elderly subjects

This study compared the effect of dynamic hip screw (DHS) and proximal femoral nail anti-rotation (PFNA) in the treatment of intertrochanteric femoral fractures of elderly subjects and evaluated the effect of PFNA internal fixation. Two hundred and sixteen elderly patients with intertrochanteric femoral fracture who received treatment in Binzhou Medical University Hospital, Shandong, China were selected. They were divided into a PFNA group which adopted PFNA for internal fixation and a DHS group which adopted DHS for internal fixation, 108 cases in each group. The physical condition of the patients in the two groups were recorded on admittance. The fracture was typed according to Evans-Jensen classification criteria. Patients were followed up after surgery to evaluate the postoperative recovery and Harris score of hip joint function. Except for the length of hospital stay, the length of incision, interoperative blood loss, volume of drainage and duration of operation of the PFNA group were all superior to those of the DHS group (P less than 0.05); the incidence of postoperative complications of the PFNA group was lower than that of the DHS group (P less than 0.05); the early Harris score of the treatment was superior to that of the DHS group, and there was no remarkable difference (P>0.05). PFNA has more advantages than DHS in treating intertrochanteric femoral fracture of the elderly; hence it is worth wide application in clinical use.

Surgical Outcomes After Open, Laparoscopic, and Robotic Gastrectomy for Gastric Cancer

BACKGROUND

In contrast to the significant advantages of laparoscopic versus open gastrectomy, robotic gastrectomy has shown little benefit over laparoscopic gastrectomy. This study aimed to compare multi-dimensional aspects of surgical outcomes after open, laparoscopic, and robotic gastrectomy.

METHODS

Data from 915 gastric cancer patients who underwent gastrectomy by one surgeon between March 2009 and May 2015 were retrospectively reviewed. Perioperative parameters were analyzed for short-term outcomes. Surgical success was defined as the absence of conversion to open surgery, major complications, readmission, positive resection margin, or fewer than 16 retrieved lymph nodes.

RESULTS

This study investigated 241 patients undergoing open gastrectomy, 511 patients undergoing laparoscopic gastrectomy, and 173 patients undergoing robotic gastrectomy. For each approach, the respective incidences were as follows: conversion to open surgery (not applicable, 0.4%, and 0%; p = 0.444), in-hospital major complications (5.8, 2.7, and 1.2%; p = 0.020), delayed complications requiring readmission (2.9, 2.0, and 1.2%; p = 0.453), positive resection margin (1.7, 0, and 0%; p = 0.003), and inadequate number of retrieved lymph nodes (0.4, 4.1, and 1.7%; p = 0.010). Compared with open and laparoscopic surgery, robotic gastrectomy had the highest surgical success rate (90, 90.8, and 96.0%). Learning-curve analysis of success using cumulative sum plots showed success with the robotic approach from the start. Multivariate analyses identified age, sex, and gastrectomy extent as significant independent parameters affecting surgical success. Surgical approach was not a contributing factor.

CONCLUSIONS

Open, laparoscopic, and robotic gastrectomy exhibited different incidences and causes of surgical failure. Robotic gastrectomy produced the best surgical outcomes, although the approach method itself was not an independent factor for success.

[The multicenter study on the registration and follow-up of low anticoagulation therapy for the heart valve operation in China]

OBJECTIVE

To investigate the optimal anticoagulation methods and monitoring strategy for Chinese patients undergoing heart valve replacement, which is potentially quite different from western populations.

METHODS

In this multicenter prospective cohort study, the anticoagulation and monitoring strategy data was acquired from 25 773 in-hospital patients in 35 medical centers and 20 519 patients in outpatient clinic in 11 medical centers from January 1st, 2011 to December 31th, 2015.

RESULTS

As for in-hospital patients, mean age of study population was (48.6±11.2) years old; main etiology of valve pathology was rheumatic (87.5%) origin among study cohort; 94.8% of study population received mechanical valve implantation; international normalized ratio (INR) monitoring (in all the study centers) and low-intensity anticoagulation strategy (31 hospitals chose target INR range of 1.5-2.5, and actual values of INR among 89.2% of 100 069 in-hospital monitoring samples were 1.5-2.5), with mean actual INR values of 1.84±0.53, and warfarin dosage of (2.82±0.93) mg/d were widely adopted among the study centers; strategies of in-hospital warfarin administration were similar in all the study centers; complication rates of low-intensity anticoagulation strategy were low in severe hemorrhage (0.02%), thrombosis (0.05%), and thromboembolism (0.05%) events, without anticoagulation-related death.As for 18 974 outpatient clinic patients, the follow-up rate was 92.47%, with a total of 30 012 patient-years (Pty). Anticoagulation-related morbidity and mortality rates were 0.67% and 0.15% Pty; major hemorrhage morbidity and mortality rates were 0.25% and 0.13% Pty; thromboembolism morbidity and mortality rates were 0.45% and 0.03% Pty.The mean dosage of warfarin daily dosage was (2.85±1.23) mg/d and INR value was 1.82±0.57.No significant regional difference in the intensity of anticoagulation therapy was noted during the study.

CONCLUSIONS

INR can be used as a normalized indicator for intensity of anticoagulation therapy in China.The optimal anticoagulation intensity with INR range from 1.5 to 2.5 is safe and effective for Chinese patients with heart valve replacement, and there is no significant regional difference in the intensity of anticoagulation therapy.

[Clinical experience of 302 cases with brain abscess]

Objective: To compare the diagnosis and treatment experience of brain abscesses and improve prognosis. Methods: The data of 302 patients of brain abscess at Department of Neurosurgery in Tianjin Medical University General Hospital from 1980 to 2014 was analyzed retrospectively. There were 215 male and 87 female patients aged from 11 to 82 years with mean age of (30±8) years. The patients was divided into 1980-2001 group and 2002-2014 group according to different diagnosis and the treatment methods. The therapy methods include operation and conservative treatment. There were 196 cases received operation, including 95 cases of excision, 89 cases of ventriculopuncture, 12 cases of excision after ventriculopuncture, 106 cases received drug conservative therapy. Two groups of information including clinical manifestation, abscess location, therapeutic effect and prognosis were compared by χ(2) test. Results: Compared to 1980-2001 group, adjacent infection incidence declined(χ(2)=8.000, P=0.005). The ratio of single abscess declined and multiple abscess increased(χ(2)=11.060, P=0.001), the infection proportion of frontal lobe and temporal lobe decreased(χ(2)=9.080, P=0.003; χ(2)=15.440, P=0.000). The ratio of headache and vomit and papilledema declined significantly(χ(2)=23.290, P=0.000; χ(2)=21.020, P=0.000; χ(2)=2.290, P=0.001). Total mortality of 302 patients were 23 cases and 5 cases of 1980-2001 group and 2002-2014 group (10.4% vs. 6.3%, χ(2)=1.180, P=0.277). However, there were statistical difference in postoperative mortality between both groups (14.4% vs. 4.0%, χ(2) =3.880, P=0.049). Conclusion: With the application of antibiotics and the development of neurosurgical techniques, the prognosis of brain abscess has been improved.

Thermosetting Polyimides with Improved Impact Toughness and Excellent Thermal and Thermo-Oxidative Stability

Thermoset polyimides were prepared by thermally curing B-staged endcapped polyimide resins that were obtained by thermally baking PMR polyimide matrix resins. The polyimide matrix resins were prepared by incorporating flexible ether-bridged aromatic segments [–Ar–O–Ar–] into PMR polyimide backbone to improve their processability and impact toughness. Experimental results indicated that the B-staged polyimide resins possessed adjustable and easily controllable thermal processability which ensure that thermoset polyimides are produced with improved impact strength and high glass transition temperature compared with PMR-15. Thermal and thermo-oxidative stability as well as hygrothermal resistance of the thermoset polyimides were also systemically investigated.

Processable Polyimides with High Glass Transition Temperature and High Storage Modulus Retention at 400°C

End-capped polyimide precursor solutions in ethyl alcohol were prepared by incorporating carbonyl groups into the polymer backbone of a second-generation PMR ( in situ polymerization of monomer reactants) polyimide, PMR-II-50, which exhibited good features as a matrix resin for carbon-fibrereinforced composites. Cured polyimides were prepared in an analogous process as the PMR-II polyimides. The thermal and thermo-oxidative stability of the cured polyimides was systemically investigated. It was found that the cured polyimide containing a 1:1 mole ratio of the carbonyl group [–C(O)–] to the hexafluoroisopropyl group [–C(CF3)2–] in the polymer backbone possessed a very high glass transition temperature (440 °C) and an excellent thermal decomposition temperature (576 °C). The onset temperature of the storage modulus curve was measured at about 400 °C with high retention ( >55%) of the storage modulus at 400 °C, compared to 10–15% of the corresponding PMR-II polyimide. Carbon-fibre-reinforced composites also showed a high onset temperature of the storage modulus (420 °C) and high storage modulus retention ( >85%) at 400 °C. Preliminary results indicated that the composite laminate exhibited excellent mechanical strength retention at 371 °C, which was superior to that of CF/PMR-II composites.

Preparation and Properties of PMR-II Polyimide/Chopped Quartz Fibre Composites

High-temperature polyimide composites with low and stable dielectric properties were produced by thermally curing prepolyimide moulding compounds which were prepared by the wet impregnation of chopped short quartz fibres with a PMR-II polyimide matrix resin solution, followed by the evaporation of the solvent with vigorous stirring. The mechanical properties, thermo-oxidative stability as well as the dielectric and electric properties of the composites were studied. The experimental results showed that the composites exhibit outstanding mechanical properties and excellent thermal and thermo-oxidative stability at temperatures as high as 371 °C. It was revealed that both the dielectric constant (∼3.0) and loss tangent (∼10−3) of the composites were not obviously changed with a frequency in the broadband wavelength (1 kHz–20 GHz).