BACKGROUND:Muscle weakness is a common symptom after coronavirus disease 2019(COVID-19)infection and affects the ability to perform daily activities in humans during recovery.Low-frequency pulsed magnetic field stimulation at a strength of 1.5 mT and a frequency of 3 300 Hz can enhance the maximal voluntary contraction and strength endurance of human skeletal muscle by inducing and activating classical transient receptor potential channel 1(TRPC1),which produces a series of pathological support effects on muscle tissue.It has not been studied whether this means will improve muscle weakness in patients recovering from COVID-19. OBJECTIVE:To select the low-frequency pulsed magnetic field for magnetic stimulation of lower limb muscle groups in patients with COVID-19,in order to observe the effect of this stimulation on the improvement of muscle weakness of lower limb muscle groups in patients with COVID-19 during the recovery period. METHODS:Fourteen patients infected with COVID-19(Omicron strain)positive for Innovita COVID-19 Ab Test(Colloidal Gold)and accompanied by muscle weakness were recruited and randomly divided into two groups:a test group receiving magnetic field stimulation and a control group receiving sham treatment,respectively.The total duration of the trial was 3 weeks.The test group was given low-frequency pulsed magnetic stimulation of the lower limbs every 48 hours and the control group was given the same intervention procedure as the test group but with sham stimulation.Patients in both groups were not informed whether the magnetic stimulation apparatus was running or not.Nine sessions were performed in both groups and the changes in the maximum voluntary contraction,explosive leg force and strength endurance of the local muscle groups of the lower limbs were subsequently observed in both groups. RESULTS AND CONCLUSION:Among the eight local muscle groups collected,seven local muscle groups in the test group showed an increase in the maximum voluntary contraction value after 3 weeks of low-frequency pulsed magnetic field stimulation.In the control group,there were only three muscle groups with improvement in the maximum voluntary contraction.The rate of improvement in the anterior and posterior muscle groups of the left leg in the test group was significantly higher than that in the control group.The longitudinal jump height and peak angular velocity of the knee joint in both groups were improved compared with the pre-test measurement,and the elevation rate of jumping height in the test group was higher than that in the control group.Under the fatigue condition,the decline rates of peak angular velocity of the knee joint and jumping height in the test group decreased significantly,while those in the control group did not change significantly.The above data confirmed that the low-frequency pulsed magnetic field stimulation with the intensity of 1.5 mT and frequency of 3 300 Hz could improve the muscle strength of more local muscle groups in the lower limbs of patients with COVID-19 during the recovery period compared with the human self-healing process,and the whole-body coordination ability and functional status based on explosive leg force of the legs could be significantly improved.Therefore,low-frequency pulsed magnetic field stimulation can be used as an effective,non-exercise rehabilitation tool to improve muscle weakness in the lower limbs of patients with COVID-19.

Maturity-onset diabetes of the young 3 (MODY3) is an autosomal dominant monogenic diabetes mellitus characterized by defective β-cell function and non-insulin-dependent early-onset diabetes mellitus. The facts that patients with MODY3 are often misdiagnosed as type 1 and type 2 diabetes mellitus and genetic diagnosis is expensive, make its diagnosis very challenging. In this study, we reported a case of MODY3, which was verified to be caused by a mutation in hepatocyte nuclear factor 1α gene (c.598C>T, p.Arg200Trp). In addition, the patient had a neuroendocrine tumor simultaneously, and a KMT2D gene mutation (c.5587C>G, p.Pro1863Ala) might be associated with this leson.

Objective:To evaluate the effect of orexin-A on programmed necrosis during cerebral ischemia-reperfusion (I/R) in rats.Methods:Thirty clean-grade healthy adult male Spraugue-Dawley rats, weighing 280-320 g, were divided into 3 groups ( n=10 each) using a random number table method: sham operation group (Sham group), cerebral I/R group (I/R group) and orexin-A group (OA group). In I/R and OA groups, a rat model of global cerebral I/R injury was established by transesophageal cardiac pacing-induced cardiac arrest and cardiopulmonary resuscitation in anesthetized animals.Orexin-A 30 μg/kg (diluted to 0.5 ml in phosphate buffer solution) was intravenously injected at 10 min before establishing the model in OA group.Phosphate buffer solution 0.5 ml was intravenously injected at 10 min before establishing the model in Sham and I/R groups.The neurological deficit score (NDS) was assessed at 24 h of reperfusion, then the rats were sacrificed, and bilateral hippocampal tissues were obtained.The morphological structure of pyramidal cells in the hippocampal CA1 region was examined after HE staining, and normal pyramidal cells were counted.Western blot was used to detect the expression of receptor-interacting protein 1 (RIP1), RIP3 and mixed-lineage kinase domain-like protein (MLKL). Immuno-histochemistry was used to count RIP1, RIP3 and MLKL positive cells in the hippocampal CA1 region.The activity of superoxide dismutase (SOD) in hippocampi was determined by xanthine oxidase method, and the content of malondialdehyde (MDA) in hippocampi was determined by thiobarbituric acid method. Results:Compared with Sham group, the normal pyramidal cell count in the hippocampal CA1 region was significantly decreased, NDS was increased, the expression of RIP1, RIP3 and MLKL protein was up-regulated, the positive cell count was increased, the content of MDA in hippocampi was increased, and the activity of SOD in hippocampi was decreased in I/R and OA groups ( P<0.05). Compared with I/R group, the count of normal pyramidal cells in the hippocampal CA1 region was significantly increased, NDS was decreased, the expression of RIP1, RIP3 and MLKL protein was down-regulated, the count of positive cells was decreased, the content of hippocampal MDA was decreased, and the activity of hippocampal SOD was increased in OA group ( P<0.05). Conclusion:The mechanism by which orexin-A reduces cerebral I/R injury may be related to inhibiting programmed necrosis in rats.

Objective:To analyze the molecular epidemiology and virulence characteristics of polymyxin-resistant Klebsiella pneumoniae ( K. pneumoniae). Methods:From 2011 to 2016, 1 376 strains of K. pneumoniae were isolated from various clinical specimens of hospitalized patients in First Affiliated Hospital of Wenzhou Medical University. Agar dilution method was used to screen out the polymyxin-resistant strains.Polymerase chain reaction (PCR) was used to detect the genes related to polymyxin resistance, and real-time fluorescence quantitative PCR was used to detect the relative mRNA expression level of drug resistant genes. Pulsed-field gel electrophoresis, multilocus sequence typing and Galleria mellonella larvae infection model were performed to analyze the molecular epidemiological and virulent characteristics. Results:A total of 14 strains (1.02%) of polymyxin-resistant K. pneumoniae were detected among 1 376 K. pneumoniae isolates. Subsequent sequencing identified mutations leading to amino-acid changes (K2E, F28C) in MgrB of 10 isolates and D150G in PhoQ of nine isolates, and genes such as mcr and crrB were not detected in all drug-resistant strains. Compared with standard strains, the relative expression levels of pmrH and pmrD mRNA of these drug resistant strains were increased. Analysis of the molecular epidemiology indicated that the 14 drug-resistant strains were divided into nine clones. Galleria mellonella larvae infection model revealed polymyxin-resistant K. pneumoniae isolates had higher virulence. Conclusions:Polymyxin-resistant K. pneumoniae has mutations in mgrB and phoQ genes, and mgrB mutation may play a key role in the change of virulence profiles. The homology among the polymyxin-resistant K. pneumoniae stains in this study is low.

Objective To evaluate the effect of ulinastatin on programmed necrosis in hippocampal neurons in a rat model of global cerebral ischemia-reperfusion (I/R).Methods Forty-eight clean-grade healthy adult male Sprague-Dawley rats,aged 8 weeks,weighing 280-320 g,were divided into 3 groups (n=16 each) using a random number table method:sham operation group (Sham group),global cerebral I/R group (I/R group) and ulinastatin group (UT group).Global cerebral I/R was produced by 4-vessel occlusion method in chloral hydrate-anesthetized rats in I/R and UT groups.Ulinastatin 100 000 U/kg was injected via the tail vein at the onset of ischemia in group UT,and the equal volume of normal saline was given instead in Sham and I/R groups.Neurological deficit score (NDS) was estimated at 6,12 and 24 h of reperfusion.Animals were sacrificed at 24 h of reperfusion,brains were removed and the hippocampi were obtained for examination of pathological changes (with a light microscope) and for determination of the malondialdehyde (MDA) content and superoxide dismutase (SOD) activity (by spectrophotometry),and expression of receptor-interacting protein kinase 1 (RIPK1),RIPK3,and mixed lineage kinase domain-like protein (MLKL) in hippocampal tissues (by Western blot).Results Compared with Sham group,the NDS was significantly increased at each time point,the MDA content was increased,the SOD activity was decreased,and the expression of RIPK1,RIPK3 and MLKL was up-regulated in I/R and UT groups (P＜ 0.05).Compared with I/R group,the NDS was significantly decreased at each time point,the MDA content was decreased,the SOD activity was increased,and the expression of RIPK1,RIPK3 and MLKL was down-regulated in UT group (P＜0.05).The pathological changes of hippocampi were significantly attenuated in UT group when compared with I/R group.Conclusion The mechanism by which ulinastatin ameliorates global cerebral I/R injury is related to inhibiting programmed necrosis in hippocampal neurons of rats.

Objective To evaluate the role of nuclear factor erythroid 2-related factor 2 ( Nrf2 ) signaling pathway in endoplasmic reticulum stress response during lipopolysaccharide ( LPS)-induced acute lung injury ( ALI) in mice. Methods Forty clean-grade healthy male C57BL∕6 mice, aged 6-8 weeks, weighing 22-26 g, were divided into 4 groups ( n=10 each) using a random number table method: control group ( group C) , group ALI, salubrinal group ( group S) and salubrinal plus brusatol group ( group S+B) . Animals were intratracheally instilled with 5 mg∕kg of LPS diluted in normal saline to establish the model of ALI. Animals were intratracheally instilled with 100 μl of normal saline in group C. Mice in group S were intraperitoneally injected with endoplasmic reticulum stress response inhibitor 1 mg∕kg salubrinal at 1 and 24 h after LPS instillation. Mice of group S+B were intraperitoneally injected with brusatol 2 mg∕kg once every other day for 10 days prior to LPS instillation, and the other treatments were similar to those previously de-scribed in group S. Mice were sacrificed at 48 h after LPS administration, and lungs were removed for mi-croscopic examination of the pathological changes of lung tissues which were scored and for determination of contents of IL-17A, tumor necrosis factor-alpha ( TNF-α) and interleukin-6 ( IL-6) in lung tissues ( by en-zyme-linked immunosorbent assay) and expression of Nrf2, CCAAT∕enhancer-binding protein homologous protein (CHOP) and caspase-12 in lung tissues (by Western blot). Lung water content was calculated. Results Compared with group C, the lung water content and contents of IL-17A, TNF-α and IL-6 were significantly increased, the expression of CHOP and caspase-12 in cytoplasma was up-regulated, and the ex-pression of Nrf2 in nuclei was down-regulated in ALI and S+B groups, and the lung water content and con-tents of IL-17A, TNF-α and IL-6 were significantly increased, the expression of Nrf2 in nuclei and CHOP in cytoplasma was up-regulated, and the expression of caspase-12 was down-regulated in group S ( P<0. 05) . Compared with group ALI, the lung water content and contents of IL-17A, TNF-α and IL-6 were significantly decreased, the expression of CHOP and caspase-12 in cytoplasma was down-regulated, the ex-pression of Nrf2 in nuclei was up-regulated ( P<0. 05) , and the pathological changes were significantly at-tenuated in group S. Compared with group S, the lung water content and contents of IL-17A, TNF-α and IL-6 were significantly increased, the expression of CHOP and caspase-12 in cytoplasma was up-regulated, the expression of Nrf2 in nuclei was down-regulated ( P<0. 05) , and the pathological changes of lung tis-sues were accentuated in group S+B. Conclusion Nrf2 signaling pathway is involved in the process of en-doplasmic reticulum stress response during LPS-induced ALI in mice.

Objective To evaluate the effect of pulsed radiofrequency (PRF) on spinal adenosine triphosphate (ATP)-P2X4-NLRP3 signaling pathway in rats with neuropathic pain.Methods Forty healthy clean-grade adult male Sprague-Dawley rats,aged 2-3 months,weighing 220-260 g,were divided into 4 groups (n =10 each) using a random number table method:sham operation group (group S),neuropathic pain group (group NP),sham PRF group (group SPRF) and PRF group.Neuropathic pain was induced by chronic constriction injury to the left sciatic nerve of anesthetized rats.Rats received PRF treatment on 7th day after establishing the model in group PRF.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured before establishing the model (T0) and at 3,7,10,14,21 and 28 days after establishing the model (T1-6).The rats were then sacrificed and the spinal cord was removed for determination of P2X4 and NLRP3 expression (by Western blot) and interleukin-1beta (IL-1β),IL-2,IL-6 and tumor necrosis factor-alpha (TNF-α) contents (by enzymelinked immunosorbent assay).Results Compared with group S,the MWT and TWL were significantly decreased at T1-6,the expression of P2X4 and NLRP3 was up-regulated,and the contents of IL-1β,IL-2,IL-6 and TNF-α were increased in NP,SPRF and PRF groups (P＜0.05).Compared with group NP and group SPRF,the MWT and MWT were significantly increased at T3-6,the expression of P2X4 and NLRP3 was down-regulated,and the contents of IL-1 β,IL-2,IL-6 and TNF-α were decreased in group PRF (P＜0.05).Conclusion The mechanism by which PRF alleviates neuropathic pain is related to inhibiting ATP-P2X4-NLRP3 signaling pathway in rats.

Objective To investigate the effect of Kinesio Taping on interleukin-1β(IL-1β),tumor necrosis factor α(TNF-α)and matrix metalloproteinase-3 (MMP-3)in synovial fluid of patients with knee osteoarthritis in early and middle stage.Methods A total of 84 patients with knee osteoarthritis who met the inclusion/exclusion criteria were randomly selected and divided into the control group treated with placebo(kinesiology tape without elasticity)and the experimental group treated with Kinesio Tape.Both two tapes were changed every two days,with 15 times of changes as a course of treatment.Synovial fluid sample was drawn before and one week after treatment,and was used for measuring Levels of 1L-1β,TNF-α and MMP-3 by enzyme-linked immunosorbent assay (ELISA).and knee function was evaluated before and 1 week after treatment.Results Compared with pre-treatment,the levels of IL-1β,TNF-α and MMP-3 in synovial fluid were significantly decreased in the experimental group after treatment [(20.07 ± 6.94) ng/Lvs.(38.12 ± 5.93) ng/L,(42.42±8.76)ng/Lvs.(58.23±9.54)ng/L,(11.28±1.99)μg/L vs.(15.67±2.21)μg/L,t =12.81,7.91 and 9.57,all P＜0.05].The levels of IL-1β,TNF-α and MMP-3 in synovial fluid were lower in the experimental group after treatment than before treatment[(20.07±6.94)ng/L vs.(38.12±5.93)ng/L,(42.42±8.76)ng/L vs.(58.23±9.54)ng/L,(11.28 ±1.99)μg/L vs.(15.67±2.21)ng/L,t =12.81,7.91 and 9.57,all P＜0.05],and were lower in the experimental group after treatment than in control after treatment[(20.07±6.94)ng/L vs.(37.97±6.21)ng/L,(42.42±8.76)ng/L vs.(57.04 ±8.73)ng/L,(11.28± 1.99)μg/Lvs.(15.01± 2.56)μg/L,t =12.46,7.66 and 7.46,all P＜0.05]Lysholm score was significantly higher in the experimental group after treatment than before treatment[(74.5 ± 2.6) vs.(44.7 ± 2.8),t =50.54,P ＜0.05],and was also higher in the experimental group after treatment than in the control group after treatment[(74.5±2.6) vs.(50.2± 2.3),t =45.37,P＜0.05].Conclusions Kinesio Taping can significantly reduce the levels of IL-1β,TNF-α and MMP-3 in synovial fluid of patients with knee osteoarthritis through inhibiting the inflammatory response in articular cavity.

Objective To evaluate the role of protein kinase C in the maintenance of chronic inflammatory pain in rats and the relationship with the expression of Nav1.8 in the dorsal root ganglion (DRG).Methods Thirty pathogen-free healthy female Sprague-Dawley rats,weighing 180-220 g,were divided into 3 groups using a random number table:control group (group C),chronic inflammatory pain group (group CIP) and PKC inhibitor group (group P).Normal saline 20 μl was injected into the plantar surface of the right hindpaw every day for 14 consecutive days in group C.Prostaglandin E2 100 ng was injected into the plantar surface of the right hindpaw every day for 13 consecutive days to establish the model of chronic inflammatory pain,and dimethyl sulfoxide 20μl was injected into the plantar surface of the right hindpaw on 14th day in group CIP.Prostaglandin E2 100 ng was injected into the plantar surface of the right hindpaw every day for 13 consecutive days,and PKC inhibitor GF1O9203X 100 nmol/20 μl was injected into the plantar surface of the right hindpaw on 14th day in group P.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before injection (T0) and 1,3,7 and 14 days after the last injection (T1-4).The DRGs of the lumbar segment (L4.5) were removed for determination of Nav1.8 expression using immunofluorescence and Western blot.Results Compared with group C,the MWT was significantly decreased at T1-4 in CIP and P groups,and the expression of Nav1.8 in DRGs was significantly up-regulated in group CIP (P＜0.05).Compared with group CIP,the MWT was significantly increased at T4,and the expression of Nav1.8 in DRGs was down-regulated in group P (P＜0.05).Conclusion Up-regulated expression of Nav1.8 after PKC activation in DRGs is involved in the maintenance of chronic inflammatory pain in rats.

Objective To evaluate the effect of penehychdine hydrochloride pretreatment on nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway during myocardial ischemia-reperfusion (Ⅰ/R) in rats.Methods Thirty-six clean-grade healthy male Sprague-Dawley rats,aged 2-3 months,weighing 220-240 g,were divided into 3 groups (n=12 each) using a random number table method:sham operation group (group S),myocardial Ⅰ/R group and penehyelidine hydrochloride pretreatment group (group PHC).Myocardial Ⅰ/R was induced by occlusion of the anterior descending branch of left coronary artery for 30 min followed by 120 min reperfusion.At 30 min before ischemia,penehyelidine hydrochloride 2 mg/kg was injected intraperitoneally in group PHC,and the anterior descending branch of left coronary artery was only exposed but not ligated in group S.Rats were sacrificed at the end of reperfusion,and hearts were removed for measurement of the myocardial infarct size (by 2,3,5-triphenyltetrazolium chloride staining),cell apoptosis (by TUNEL) and expression of Nrf2,heme oxygenase-1 (HO-1),NQO1 and γ-glutamylcysteine synthetase (γ-GCS) protein and mRNA (by using Western blot or real-time fluorescence quantitative polymerase chain reaction).The percentage of myocardial infarct size and apoptosis index were calculated.Results Compared with group S,the percentage of myocardial infarct size and apoptosis index were significantly increased,and the expression of Nrf2,HO-1,NQO1 and γ-GCS protein and mRNA was down-regulated in Ⅰ/R and PHC groups (P＜0.05).Compared with group l/R,the percentage of myocardial infarct size and apoptosis index were significantly decreased,and the expression of Nrf2,HO-1,NQO1 and γ-GCS protein and mRNA was up-regulated in group PHC (P＜0.05).Conclusion Penehyclidine hydrochloride pretreatment attenuates myocardial Ⅰ/R injury through activating Nrf2-ARE signaling pathway in rats.