[Clinical application of a quantitative method of atlantoaxial reduction angle in basilar invagination]

Objectives: To investigate the clinical application effect of a quantitative method of atlantoaxial reduction angle in basilar invagination. Methods: A retrospective analysis of clinical and radiographic data was conducted of 38 patients with complicated atlantoaxial dislocation and basilar invagination admitted to the Department of Neurosurgery, First Affiliated Hospital of Chongqing Medical University from May 2020 to May 2022. There were 5 males and 33 females, aged (53.5±9.9) years (range: 38 to 80 years). All patients underwent C_1-2 interarticular fusion cage implantation+occipital-cervical fixation by pressing rob with the cantilever technique. The atlantoaxial reduction model of previous studies by our team was used to calculate the reduction angles before surgery. Then titanium rods of prebending angle were prepared according to the calculation before the operation. After that quantitative reduction of angle was performed during the operation. The paired t-test was used to compare the difference between the theoretical and actual reset value. Results: The theoretical reduction angle of all patients was (10.62±1.78)° (range: 6.40° to 13.20°), the actual reduction angle was (10.53±1.63)° (range: 6.70° to 13.30°) and there was no statistical difference between them (t=1.688, P=0.100). The theoretical posterior occipitocervical angle after the operation of all patients was (117.37±5.88)° (range: 107.00° to 133.00°), the actual posterior occipitocervical angle after the operation was (118.25±6.77)° (range: 105.40° to 135.80°) and there was no statistical difference between them (t=-0.737, P=0.466). The postoperative follow-up time of the patients was more than 6 months and the symptoms of all patients were relieved. All patients had satisfactory fusion between small joints without incision infection, internal fixation fracture, displacement, atlantoaxial redislocation, and other long-term complications. Conclusion: The quantitative method of atlantoaxial reduction angle in basilar invagination can calculate the theoretical reduction angle of the clivus axis angle and guide the preparation of the pre-bending titanium rod before surgery, so as to realize the quantification of the atlantoaxial reduction angle.

[Effect of rotigotine on the quality of emergence from general anesthesia in patients undergoing deep brain stimulation]

Objective: To investigate the effect of rotigotine on the quality of emergence from general anesthesia in patients undergoing deep brain stimulation (DBS). Methods: A total of 42 patients (31 males and 11 females, aged 55-85 years) undergoing DBS surgery under general anesthesia in the First Affiliated Hospital of Zhengzhou University from March 2020 to October 2021 were selected. The patients were divided into non-rotigotine group (n=21) and rotigotine group (n=21) by using a random number table according to whether rotigotine patch was used. Postoperative recovery time, extubation time, length of postanesthesia care unit (PACU) stay, and grades of muscle tension, swallowing function and salivary secretion during recovery were compared between the two groups. Meanwhile, the incidence of adverse events during extubation was also compared. Results: The postoperative recovery time, extubation time and length of PACU stay in rotigotine group were (20.3±2.6) min, (30.6±3.1) min and (46.4±3.9) min, respectively, which were shorter than those of non-rotigotine group [(29.0±5.8) min, (42.6±10.0) min and (63.0±18.9) min, respectively] (all P<0.05). The grades of postoperative muscle tension, swallowing function and salivary secretion in rotigotine group [M(Q₁, Q₃)] were 1(1, 2), 1(1, 2) and 1(1, 1), respectively, which were lower than those of non-rotigotine group [2(2, 3), 2(2, 2) and 2(1, 2), respectively] (P=0.001, 0.002 and 0.011). The incidence of adverse events during anesthesia extubation in rotigotine group was 14.3% (3/21), which was lower than that of non-rotigotine group [42.9% (9/21), P=0.040]. Conclusion: Rotigotin patch is helpful to improve the quality of emergence from general anesthesia in patients undergoing DBS and reduce the occurrence of adverse events during extubation.

[Geometric model of reduction in basilar invagination with atlantoaxial dislocation and its clinical application]

Objectives: To establish a geometric model of the atlantoaxial dislocation and basilar invagination reduction,and examine its value for clinical application. Methods: A retrospective analysis of 35 patients with atlantoaxial dislocation and basilar invagination admitted to the Department of Neurosurgery,First Affiliated Hospital of Chongqing Medical University from May 2018 to May 2020 was conducted.There were 5 males and 30 females,aged (48±15) years(range: 19 to 69 years). The geometric model of the atlantoaxial reduction was established based on the mid-sagittal section of the cervical spine. The relevant data were calculated according to the geometric model before operation,and the fusion cage of the corresponding height was placed into C_1-2 facet joint of patient for quantitative reduction. The theoretical reset value, actual reset value, postoperative symptoms and complications were collected. The paired t-test was used to compare the difference between theoretical and actual reset value to verify the reliability of the geometric model. Results: The theoretical vertical reduction distance of all patients was (5.79±2.96) mm(range:1.52 to 10.96 mm),and the actual vertical reduction distance was (7.43±2.96)mm(range: 1.40 to 12.77 mm),and there was no statistical difference between them(t=-1.96,P=0.069).The theoretical reduction angle was (10.80±2.24)°(range: 7.09 to 14.86°), the actual reduction angle was (10.64±7.00)°(range: 3.50 to 20.50°),and there was no statistical difference between them (t=0.09, P=0.933). At 6 months follow-up, 35 patients achieved satisfactory atlanto-axial joint fusion, and the symptoms were relieved. No internal fixation system displacement, fracture, wound infection and other complications occurred. Conclusion: This geometric model can estimate the vertical reduction distance and the reduction angle of the axial before operation,and provide a reference for the height of the fusion cage so as to avoid under or over-reduction.

Restorable, high-strength poly(N-isopropylacrylamide) hydrogels constructed through chitosan-based dual macro-cross-linkers with rapid response to temperature jumps

Thermo-responsive, high mechanical poly(N-isopropylacrylamide) hydrogels with excellent recoverability and rapid response rate are constructed on chitosan-based dual macro-cross-linkers.

Alginate fibers embedded with silver nanoparticles as efficient catalysts for reduction of 4-nitrophenol

Silver nanoparticles (AgNPs) have attracted much attention as promising catalysts in various electron transfer reactions due to their high catalytic efficiency.

Hyperbaric oxygen preconditioning protects against traumatic brain injury at high altitude

BACKGROUND

Recent studies have shown that preconditioning with hyperbaric oxygen (HBO) can reduce ischemic and hemorrhagic brain injury. We investigated effects of HBO preconditioning on traumatic brain injury (TBI) at high altitude and examined the role of matrix metalloproteinase-9 (MMP-9) in such protection.

METHODS

Rats were randomly divided into 3 groups: HBO preconditioning group (HBOP; n = 13), high-altitude group (HA; n = 13), and high-altitude sham operation group (HASO; n = 13). All groups were subjected to head trauma by weight-drop device, except for HASO group. HBOP rats received 5 sessions of HBO preconditioning (2.5 ATA, 100% oxygen, 1 h daily) and then were kept in hypobaric chamber at 0.6 ATA (to simulate pressure at 4000m altitude) for 3 days before operation. HA rats received control pretreatment (1 ATA, room air, 1 h daily), then followed the same procedures as HBOP group. HASO rats were subjected to skull opening only without brain injury. Twenty-four hours after TBI, 7 rats from each group were examined for neurological function and brain water content; 6 rats from each group were killed for analysis by H&E staining and immunohistochemistry.

RESULTS

Neurological outcome in HBOP group (0.71 +/- 0.49) was better than HA group (1.57 +/- 0.53; p < 0.05). Preconditioning with HBO significantly reduced percentage of brain water content (86.24 +/- 0.52 vs. 84.60 +/- 0.37; p < 0.01). Brain morphology and structure seen by light microscopy was diminished in HA group, while fewer pathological injuries occurred in HBOP group. Compared to HA group, pretreatment with HBO significantly reduced the number of MMP-9-positive cells (92.25 +/- 8.85 vs. 74.42 +/- 6.27; p < 0.01).

CONCLUSIONS

HBO preconditioning attenuates TBI in rats at high altitude. Decline in MMP-9 expression may contribute to HBO preconditioning-induced protection of brain tissue against TBI.

Effects of turbulent air on human thermal sensations in a warm isothermal environment

Air movement can provide desirable cooling in "warm" conditions, but it can also cause discomfort. This study focuses on the effects of turbulent air movements on human thermal sensations through investigating the preferred air velocity within the temperature range of 26 degrees C and 30.5 degrees C at two relative humidity levels of 35% and 65%. Subjects in an environmental chamber were allowed to adjust air movement as they liked while answering a series of questions about their thermal comfort and draft sensation. The results show that operative temperature, turbulent intensity and relative humidity have significant effects on preferred velocities, and that there is a wide variation among subjects in their thermal comfort votes. Most subjects can achieve thermal comfort under the experimental conditions after adjusting the air velocity as they like, except at the relative high temperature of 30.5 degrees C. The results also indicate that turbulence may reduce draft risk in neutral-to-warm conditions. The annoying effect caused by the air pressure and its drying effect at higher velocities should not be ignored. A new model of Percentage Dissatisfied at Preferred Velocities (PDV) is presented to predict the percentage of feeling draft in warm isothermal conditions.

Combination of sotalol and quinidine in a canine model of torsades de pointes: no increase in the QT-related proarrhythmic action of sotalol

INTRODUCTION

Clinical treatment with a combination of Class IA and III antiarrhythmic drugs is not recommended, as they both favor bradycardia-dependent proarrhythmic events such as torsades de pointes (TdP). However, this theoretical additive effect on ventricular repolarization has never been demonstrated and could be questioned as other Class I drugs, such as mexiletine, a Class IB drug, limit the number of sotalol-induced TdP in dogs with AV block, suggesting the possibility of an antagonistic action of Class I properties against Class III effects.

METHODS AND RESULTS

We compared the electrophysiologic and proarrhythmic effects of sotalol (Class III) alone and combined with quinidine (Class IA) in a canine model of acquired long QT syndrome. Seven hypokalemic (K+: 3 +/- 0.1 mEq/L) dogs with chronic AV block had a demand pacemaker implanted and set at a rate of 25 beats/min. They were submitted to two (sotalol-alone and sotalol-plus-quinidine) experiments 48 hours apart using a randomized cross-over protocol. They were pretreated with quinidine (10 mg/kg + 1.8 mg/kg per hour) or saline infused throughout the experiment, and given sotalol (4.5 mg/kg + 1.5 mg/kg per hour) for 2 hours, 30 minutes after the beginning of the pretreatment infusion during both experiments. Ventricular and atrial cycle lengths were similarly increased by sotalol after quinidine or saline. The sotalol-induced prolongation of the QT interval was significantly shorter in quinidine-pretreated dogs (24 +/- 7 msec after quinidine vs 40 +/- 8 msec after saline). Fewer dogs developed TdP: significantly during the first hour of infusion (1/7 sotalol-plus-quinidine vs 6/7 sotalol-alone dogs, P < 0.05) but nonsignificantly during the second hour (3/7 vs 6/7).

CONCLUSION

In this model, the sotalol-plus-quinidine combination is at least no more arrhythmogenic than either of the drugs given alone.

Morphometric diagnosis of bladder tumor

This paper reports the morphometric analysis results of 100 cases of bladder tumor cells with a Q-900 computer-assisted image analysis system. According to the nuclear area, axis ratio and area ratio of tumor nuclei, bladder transitional cell tumors were divided into 4 grades. This system is called the morphometric grading system (M grading). The results show that the higher the M grading, the lower the survival rate and the higher the recurrence rate. As the M grade increases the tumors could be accompanied by muscular invasion. When recurring, the tumor has a poor prognosis if M grading increases. We conclude that the morphometric grading system is able to yield a quantitative pathologic diagnosis and can predict the biological behavior of bladder tumors. Recently, new techniques for diagnosing and predicting the biological behavior of bladder tumors have been developed. One such technique is morphometric analysis of bladder transitional cell carcinoma with computer-assisted image instruments [1]. Because this morphometric method is easily applicable to pathological section routinely stained with HE and the results are reproducible and more objective, the studies about morphometric analysis of bladder tumor have increased in recent times. This paper reports the preliminary morphometric analysis results of bladder tumor cells examined by a Q-900 image analysis instrument for 100 cases.