An experimental model of peripheral nerve electrical injury in rats.

INTRODUCTION: Although several studies have investigated models of nerve electrical injury, only a few have focused on electrical injury to peripheral nerves, which is a common and intractable problem in clinical practice. Here, we describe an experimental rat model of peripheral nerve electrical injury and its assessment. METHODS: A total of 120 animals were subjected to short-term corrective electrostimulation (50 Hz, 1-s duration) applied at varying voltages (control, 65, 75, 100, 125, and 150 V) to the exposed left sciatic nerve. Behavioural testing, electrophysiological measurements, and histopathological observation of the sciatic nerve were conducted at 1-, 2-, 4-, and 8-w follow-ups. RESULTS: No functional defects were noted in the groups that received 65-V stimulation at any time point. Sciatic nerve functional defects were found after 2 w in animals that received 75-V stimulation, but function returned to normal after 4 w. In animals that received 100-V and 125-V stimulation, functional defects were observed at 4 w, but had partially recovered by 8 w. Conversely, animals that received 150-V stimulation did not show recovery after 8 w. CONCLUSION: We presented a model of peripheral nerve electrical injury that avoided the interference of various external factors, such as current instability, compression of the surrounding tissues, and altered blood supply. The model allowed quantitation and ranking of the nerve injury into four degrees. It facilitated effective evaluation of nerve function impairment and repair after injury. It can be used post-surgically to evaluate peripheral nerve impairment and reconstruction and enables translational interpretation of results, which may improve understanding of the mechanisms underlying the progression of peripheral nerve electrical injury.

Koumine ameliorates concanavalin A-induced autoimmune hepatitis in mice: involvement of the Nrf2, NF-κB pathways, and gut microbiota.

Gelsemiumelegans(Gardner. & Chapm.) Benth. has long been considered a traditional Chinese medicine effective against rheumatoid pain, cancer, cirrhosis, and skin diseases. Koumine (KM), the most abundant alkaloid in G.elegans Benth., demonstrates a variety of biological effects, including antitumor, analgesic, anxiolytic, anti-inflammatory, antidepressant, antioxidant, immunoregulatory, and hepatoprotective effects. Furthermore, the relatively low toxicity of KM makes it a promising drug candidate. This study aimed to investigate the protective effects of KM and its possible mechanisms using a concanavalin A (Con A)-induced autoimmune hepatitis (AIH) model in mice. Mice were orally administered different doses of KM for 14 d before Con A tail vein injections. The effects of KM on serum biochemical markers and liver histopathology were then evaluated 12 h after Con A exposure. The Nrf2 and NF-κB signaling pathways and alterations in gut microbiota were determined using western blotting, immunohistochemistry, and 16S rRNA sequencing to explore the underlying mechanisms of KM exposure. KM pretreatment dose-dependently decreased serum liver injury markers (Alanine aminotransferase, and aspartate aminotransferase) and cytokine levels (Tumor necrosis factor-α and interleukin-6), as well as the liver pathological damage triggered by Con A. Furthermore, the results of the multi-technique analysis indicated that KM activated the Nrf2 pathway, upregulated the expression of anti-oxidation factors HO-1 and Nrf2, and downregulated the expression of Keap1. Moreover, the NF-κB signaling pathway was inhibited. Interestingly, pre-treatment with KM also significantly improved the composition of the gut microbiota probably because it increases the richness of probiotics. Our findings suggest that KM pretreatment could attenuate Con A-induced AIH, the Nrf2 and NF-κB signaling pathways, and that gut microbiota are involved in the process of the hepatoprotective effect. This study provides a theoretical basis for the development of KM as an effective agent against AIH.

Rapid, simple, and economical LC-MS/MS method for simultaneous determination of ceftazidime and avibactam in human plasma and its application in therapeutic drug monitoring.

WHAT IS KNOWN AND OBJECTIVE: Carbapenem-resistant Gram-negative bacterial pathogens continue to threaten public health. Avibactam (AVI), a novel non-ß-lactam ß-lactamase inhibitor, has been approved for use with ceftazidime (CAZ) mainly against carbapenem-resistant Enterobacteriaceae. Therapeutic drug monitoring (TDM) is urgently needed to optimize dosage regimens to maximize efficacy, minimize toxicity, and delay the emergence of resistance. This study aims to develop and validate a rapid, simple, and economical LC-MS/MS method for simultaneous determination of CAZ/AVI in human plasma. METHODS: Samples were processed by simple protein precipitation, and gradient elution strategy was applied to separate CAZ and AVI on a reverse-phase C18 column; with subsequent detection by the mass spectrometer in a positive and negative ion switching mode. Plasma samples from patients were analysed. RESULTS AND DISCUSSION: A 4-min run of LC-MS/MS was developed. The precision, trueness, matrix effect, extraction recovery, carry-over, dilution integrity, and stability were all acceptable for a bioanalytical method. The method was successfully applied to the determination of CAZ and AVI in patients, and a considerable PK variability of CAZ/AVI was observed among patients. WHAT IS NEW AND CONCLUSION: A robust, rapid, simple, and economical LC-MS/MS method for the simultaneous determination of CAZ and AVI was developed. The considerable PK variability of CAZ/AVI among patients demonstrates the clinical significance of TDM.

DEGENERATED PANICLE AND PARTIAL STERILITY 1 (DPS1) encodes a cystathionine ß-synthase domain containing protein required for anther cuticle and panicle development in rice.

Degeneration of apical spikelets and reduced panicle fertility are common reasons for low seed-setting rate in rice (Oryza sativa). However, little is known about the underlying molecular mechanisms. Here, we report a novel degenerated panicle and partial sterility 1 (dps1) mutant that showed panicle apical degeneration and reduced fertility in middle spikelets. dps1 plants were characterized by small whitish anthers with altered cuticle morphology and absence of pollen grains. Amounts of cuticular wax and cutin were significantly reduced in dps1 anthers. Panicles of dps1 plants showed an accumulation of reactive oxygen species (ROS), lower antioxidant activity, and increased programmed cell death. Map-based cloning revealed that DPS1 encodes a mitochondrial-localized protein containing a cystathionine ß-synthase domain that showed the highest expression in panicles and anthers. DPS1 physically interacted with mitochondrial thioredoxin proteins Trx1 and Trx20, and it participated in ROS scavenging. Global gene expression analysis in dps1 revealed that biological processes related to fatty acid metabolism and ROS homeostasis were significantly affected, and the expression of key genes involved in wax and cutin biosynthesis were downregulated. These results suggest that DPS1 plays a vital role in regulating ROS homeostasis, anther cuticle formation, and panicle development in rice.

A Rice PECTATE LYASE-LIKE Gene Is Required for Plant Growth and Leaf Senescence.

To better understand the molecular mechanisms behind plant growth and leaf senescence in monocot plants, we identified a mutant exhibiting dwarfism and an early-senescence leaf phenotype, termed dwarf and early-senescence leaf1 (del1). Histological analysis showed that the abnormal growth was caused by a reduction in cell number. Further investigation revealed that the decline in cell number in del1 was affected by the cell cycle. Physiological analysis, transmission electron microscopy, and TUNEL assays showed that leaf senescence was triggered by the accumulation of reactive oxygen species. The DEL1 gene was cloned using a map-based approach. It was shown to encode a pectate lyase (PEL) precursor that contains a PelC domain. DEL1 contains all the conserved residues of PEL and has strong similarity with plant PelC. DEL1 is expressed in all tissues but predominantly in elongating tissues. Functional analysis revealed that mutation of DEL1 decreased the total PEL enzymatic activity, increased the degree of methylesterified homogalacturonan, and altered the cell wall composition and structure. In addition, transcriptome assay revealed that a set of cell wall function- and senescence-related gene expression was altered in del1 plants. Our research indicates that DEL1 is involved in both the maintenance of normal cell division and the induction of leaf senescence. These findings reveal a new molecular mechanism for plant growth and leaf senescence mediated by PECTATE LYASE-LIKE genes.

[Effect of strengthening Pi and activating blood circulation therapy on serum levels of adrenocorticotrophic hormone and vascular endothelial growth factor in rheumatoid arthritis patients].

OBJECTIVE: To observe the effect of strengthening Pi and activating blood circulation therapy (SPAB) on serum levels of adrenocorticotrophic hormone (ACTH) and vascular endothelial growth factor (VEGF) in rheumatoid arthritis (RA) patients. METHODS: Seventy RA patients were randomly assigned to 3 groups. The 30 in the Chinese medicine (CM) group were treated with SPAB; the 20 in the Western medicine (WM) group were treated with indomethacin and methopterin; and the 20 in the CM-WM group were treated with the combination of the therapy in the above two groups, and the course of treatment was 3 months for all. Serum levels of ACTH and VEGF were determined before and after treatment. RESULTS: The total effective rate in the CM group was 80.0%, WM group 85.0% and CM-WM group 95.0%, the last one showed the best efficacy (P<0.05). Serum level of ACTH increased and level of VEGF decreased after treatment in all groups (P<0.05 or P<0.01), but the increment/decrement in the CM-WM group was higher than that in the other two groups (P<0.01), while comparison between that in the CW group and WM group showed insignificant difference. CONCLUSION: SPAB therapy has the effect in alleviating the condition of RA, similar to that of Western medicine, it can increase the serum level of ACTH and decrease the serum level of VEGF remarkably in RA patients.