Caffeine Consumption Influences Lidocaine Action via Pain-Related Voltage-Gated Sodium Channels: An In Vivo Animal Study

Several factors might influence the duration and efficiency of local anesthesia. This study investigates the effect of habitual caffeine intake on lidocaine action and explores the potential involvement of voltage-gated sodium channels in the interaction effect. Wistar rats were divided into four groups: (i) control (Ctrl), (ii) lidocaine intraplantar injection (LIDO), (iii) habitual caffeine intake (CAF), and (iv) lidocaine intraplantar injection and habitual caffeine intake (LIDO + CAF). Behavioral assessments, consisting of a paw pressure test for mechanical pressure sensation and a paw withdrawal latency test for thermal pain sensation, were performed at 0, 30, 60, and 90 minutes following lidocaine injection and after 10, 11, and 12 weeks of CAF intake. Pressure sensation was significantly reduced in the LIDO + CAF group compared with the control group. Moreover, the LIDO + CAF group exhibited reduced sensation compared to LIDO alone group. The LIDO + CAF combination exerted a synergistic effect at 30 and 60 minutes compared with the control. This synergistic effect was noted at 60 minutes (11 weeks of CAF intake) and at 30 minutes (12 weeks of CAF intake) compared with LIDO alone. Augmented thermal pain-relieving effects were observed in the LIDO + CAF group at all weeks compared to the control group and at 10 weeks compared to LIDO alone group. The molecular analysis of dorsal root ganglia suggested that CAF upregulated the mRNA expression of the Nav1.3, Nav1.7, and Nav1.8 sodium channel subtypes. Chronic caffeine consumption potentiates the local anesthetic action of lidocaine in an experimental animal model through mechanisms that involve the upregulation of voltage-gated sodium channels in the dorsal root ganglia.

Development and assessment of a knitted shape memory alloy-based multifunctional elbow brace

Osteoarthritis is a chronic disease that affects joint cartilage and can cause severe pain and disability. Minor neglected injuries may also result in other diseases that affect daily life. Various attempts have been made to develop wearable auxiliary devices using functional fabrics, but few have simultaneously provided both heat and pressure. Using knitted shape memory alloy (SMA) fabric, a module was manufactured that achieved bending and contraction during operation. An elbow brace that simultaneously provided heat and pressure was developed using this module. Subjective evaluation and measurements of the range of motion (ROM), changes in skin temperature ( T sk ), clothing pressure ( P c), and blood flow ( F b) were conducted on the elbow brace while being worn by 10 participants. The multifunctional elbow brace (MFEB) developed in this study generated pressure and heat that increased T sk and P c, ultimately increasing F b. In addition, the ROM of the elbow joint was increased after actuating the elbow brace. Subjective evaluation of the heat and pressure sensation demonstrated its applicability to the human body. We confirmed that the elbow brace had a positive effect on F b and increased the ROM of the joint. These results show the applicability of smart textiles to the development of various wearable devices.

Fine adaptive precision grip control without maximum pinch strength changes after upper limb neurodynamic mobilization

Before and immediately after passive upper limb neurodynamic mobilizations targeting the median nerve, grip ($$G_F$$ G F ) and load ($$L_F$$ L F ) forces applied by the thumb, index and major fingers (three-jaw chuck pinch) were collected using a manipulandum during three different grip precision tasks: grip-lift-hold-replace (GLHR), vertical oscillations (OSC), and vertical oscillations with up and down collisions (OSC/COLL/u, OSC/COLL/d). Several parameters were collected or computed from $$G_F$$ G F and $$L_F$$ L F . Maximum pinch strength and fingertips pressure sensation threshold were also examined. After the mobilizations, $$L_F$$ L F max changes from 3.2 ± 0.4 to 3.4 ± 0.4 N (p = 0.014), d$$G_F$$ G F from 89.0 ± 66.6 to 102.2 ± 59.6 $$N~\text{s}^{-1}$$ N s - 1 (p = 0.009), and d$$L_F$$ L F from 43.6 ± 17.0 to 56.0 ± 17.9 $$N~\text{s}^{-1}$$ N s - 1 ($$p<$$ p < 0.001) during GLHR. $$L_F$$ L F SD changes from 0.9 ± 0.3 to 1.0 ± 0.2 N (p = 0.004) during OSC. $$L_F$$ L F peak changes from 17.4 ± 8.3 to 15.1 ± 7.5 N ($$p<$$ p < 0.001), $$G_F$$ G F from 12.4 ± 6.7 to 11.3 ± 6.8 N (p = 0.033), and $$L_F$$ L F from 2.9 ± 0.4 to 3.00 ± 0.4 N (p = 0.018) during OSC/COLL/u. $$G_F$$ G F peak changes from 13.5 ± 7.4 to 12.3 ± 7.7 N (p = 0.030) and $$L_F$$ L F from 14.5 ± 6.0 to 13.6 ± 5.5 N (p = 0.018) during OSC/COLL/d. Sensation thresholds at index and thumb were reduced (p = 0.001, p = 0.008). Precision grip adaptations observed after the mobilizations could be partly explained by changes in cutaneous median-nerve pressure afferents from the thumb and index fingertips.

Analysis and Optimization of Low-Speed Road Noise in Electric Vehicles

When a certain electric vehicle is driving at a constant speed of 40 km/h on the rough asphalt road, the rear passenger can obviously feel the ear pressure, which seriously affects the comfort. Through the analysis of objective data, it was found that the problem was caused by the road excitation, which leads to the coupling between the mode of the backup door and the mode of the acoustic cavity, and causes the resonance of the car cavity, thus causing the ear pressure sensation. To solve this problem, this paper optimizes the backup door by means of experiment and simulation, increases the dynamic vibration absorber, makes its modal frequency avoid the acoustic cavity modal frequency, and achieves the purpose of reducing the interior noise. After optimization, the vehicle noise is reduced by 8 dBA at 42 Hz under 40 km/h working condition of rough road surface, and the ear pressure sensation is reduced at the same time, thus improving the NVH (noise, vibration, and harshness) performance of the vehicle.

Innocuous pressure sensation requires A-type afferents but not functional ΡΙΕΖΟ2 channels in humans

The sensation of pressure allows us to feel sustained compression and body strain. While our understanding of cutaneous touch has grown significantly in recent years, how deep tissue sensations are detected remains less clear. Here, we use quantitative sensory evaluations of patients with rare sensory disorders, as well as nerve blocks in typical individuals, to probe the neural and genetic mechanisms for detecting non-painful pressure. We show that the ability to perceive innocuous pressures is lost when myelinated fiber function is experimentally blocked in healthy volunteers and that two patients lacking Aβ fibers are strikingly unable to feel innocuous pressures at all. We find that seven individuals with inherited mutations in the mechanoreceptor PIEZO2 gene, who have major deficits in touch and proprioception, are nearly as good at sensing pressure as healthy control subjects. Together, these data support a role for Aβ afferents in pressure sensation and suggest the existence of an unknown molecular pathway for its detection.

Thrombosed orbital varix with mild, spontaneously resolving symptoms

Orbital varices are abnormally enlarged, thin walled veins in direct connection with normal orbital vessels. Stooping, bending, coughing or straining increase the venous tension and in this way can cause symptoms, such as bulging of the eyes (proptosis), orbital pain, bleeding, intermittent double vision. Small varices are managed by observation while larger lesions may require surgery. In our case report we demonstrate the case of a 72-year-old female patient with right sided retro-orbital pressure sensation for weeks, and exophthalmos with blurred vision for 1 week. MR investigation proved the presence of a partially thrombosed orbital varix on the right side, and a smaller, non-thrombosed varix on the left side. Observation was agreed, and the symptoms resolved spontaneously after several weeks.