It has been demonstrated that long-term space flights have a significantly greater impact on the cardiovascular, skeletal, and nervous systems of astronauts. The structural and functional alterations in the skeletal and muscular systems resulting from exposure to weightlessness can lead to the development of low back pain, significantly impairing the ability of astronauts to perform tasks and respond to emergencies. Both space flight and simulated microgravity have been shown to result in low back pain among astronauts, with the following factors identified as primary contributors to this phenomenon. The occurrence of intervertebral disc (IVD) edema results in the stimulation of type IV mechanoreceptors, which subsequently activate nociceptive afferents. The protrusion of an IVD causes compression of the spinal nerve roots. Furthermore, the elongation of the vertebral column and/or the diminished lumbar curvature of the spine exert traction on the dorsal root nerves. Paravertebral muscle degeneration leads to the inhibition of decreased nociceptive activity of the wide-dynamic range neurons of the spinal dorsal horn. Moreover, endogenous pain descending facilitation triggered by conditioning stimulation can be enhanced via the thalamic mediodorsal nuclei, while endogenous pain descending inhibition triggered by conditioning stimulation can be weakened via the thalamic ventromedial nuclei. Psychological factors may contribute to the development of low back pain. The mechanisms governing the generation, maintenance, and alleviation of low back pain in weightlessness differ from those observed in normal gravitational environments. This presents a significant challenge for space medicine research. Therefore, the elucidation of the occurrence and development mechanism of low back pain in weightlessness is important for the prevention and treatment during space flight. To reduce the incidence of low back pain during long-term missions on the space station, astronauts may choose to wear specialized space clothing that can provide axial physiological loads, designed to stimulate both musculature and skeletal structures, mitigating potential increases in vertebral column length, diminished lumbar curvature, and intervertebral disc edema and/or muscular atrophy. Additionally, assuming a “fetal tuck position” described as the knees to chest position may increase lumbar IVD hydrostatic pressure, subsequently reducing disc volume, rectifying diminished lumbar curvature, and alleviating dorsal root nerve tensions. Moreover, this position may reduce type IV mechanoreceptor facilitation and nerve impulse propagation from the sinuvertebral nerves of the annulus fibrosus. Elongated posterior soft tissues (apophyseal joint capsules and ligaments) with spinal flexion may potentially stimulate type I and II mechanoreceptors. It is also recommended to exercise the paraspinal muscles to prevent and alleviate the decrease in their cross-sectional area and maintain their structure and function. Photobiomodulation has been proved to be an effective means of activating the pain descending inhibition pathway of the central nervous system. In addition, astronauts should be encouraged to participate in mission-related activities and strive to avoid psychological problems caused by the long-term confinement in a small space station. The article presents a concise review of potential causes and targeted treatment strategies for low back pain induced by space flight or simulated microgravity in recent years. Its objective is to further elucidate the mechanisms underlying the occurrence and development of low back pain in weightless environments while providing scientific evidence to inform the development of guidelines for preventing, treating, and rehabilitating low back pain during long-term space flights.

Electromagnetic fields can regulate the fundamental biological processes involved in bone remodeling. As a non-invasive physical therapy, electromagnetic fields with specific parameters have demonstrated therapeutic effects on bone remodeling diseases, such as fractures and osteoporosis. Electromagnetic fields can be generated by the movement of charged particles or induced by varying currents. Based on whether the strength and direction of the electric field change over time, electromagnetic fields can be classified into static and time-varying fields. The treatment of bone remodeling diseases with static magnetic fields primarily focuses on fractures, often using magnetic splints to immobilize the fracture site while studying the effects of static magnetic fields on bone healing. However, there has been relatively little research on the prevention and treatment of osteoporosis using static magnetic fields. Pulsed electromagnetic fields, a type of time-varying field, have been widely used in clinical studies for treating fractures, osteoporosis, and non-union. However, current clinical applications are limited to low-frequency, and research on the relationship between frequency and biological effects remains insufficient. We believe that different types of electromagnetic fields acting on bone can induce various “secondary physical quantities”, such as magnetism, force, electricity, acoustics, and thermal energy, which can stimulate bone cells either individually or simultaneously. Bone cells possess specific electromagnetic properties, and in a static magnetic field, the presence of a magnetic field gradient can exert a certain magnetism on the bone tissue, leading to observable effects. In a time-varying magnetic field, the charged particles within the bone experience varying Lorentz forces, causing vibrations and generating acoustic effects. Additionally, as the frequency of the time-varying field increases, induced currents or potentials can be generated within the bone, leading to electrical effects. When the frequency and power exceed a certain threshold, electromagnetic energy can be converted into thermal energy, producing thermal effects. In summary, external electromagnetic fields with different characteristics can generate multiple physical quantities within biological tissues, such as magnetic, electric, mechanical, acoustic, and thermal effects. These physical quantities may also interact and couple with each other, stimulating the biological tissues in a combined or composite manner, thereby producing biological effects. This understanding is key to elucidating the electromagnetic mechanisms of how electromagnetic fields influence biological tissues. In the study of electromagnetic fields for bone remodeling diseases, attention should be paid to the biological effects of bone remodeling under different electromagnetic wave characteristics. This includes exploring innovative electromagnetic source technologies applicable to bone remodeling, identifying safe and effective electromagnetic field parameters, and combining basic research with technological invention to develop scientifically grounded, advanced key technologies for innovative electromagnetic treatment devices targeting bone remodeling diseases. In conclusion, electromagnetic fields and multiple physical factors have the potential to prevent and treat bone remodeling diseases, and have significant application prospects.

Objective: To assess the dynamic changes of microcirculation at acupoints in patients with primary dysmenorrhea and cold congelation and blood stasis syndrome using laser speckle blood flow imaging. Methods: Patients with primary dysmenorrhea and cold coagulation and blood stasis syndrome (primary dysmenorrhea group, n=53) and healthy female college students(control group, n=57) who met the inclusion and exclusion criteria from October 2020 to July 2022 were enrolled at Hebei University of Chinese Medicine. On the premenstrual and first day of menstruation, a laser speckle blood flow imaging system was used to measure the microcirculation blood flow perfusion on the surface of acupoints related to the conception, thoroughfare, and governor vessels, and stomach, spleen, and bladder meridians in the abdomen and lumbosacral regions. The dynamic changes in microcirculation were calculated based on the difference in average blood flow perfusion at each acupoint before and after menstruation. Receiver operating curve (ROC) analysis was used to analyze the diagnostic efficacy of dynamic changes in microcirculation on the surface of each acupoint. The microcirculation sensitization rate of acupoints was calculated. Results: Compared with the control group, the dynamic changes in microcirculation at the following acupoints in the primary dysmenorrhea group were increased (P<0.05): conception vessel (Yinjiao[CV7], Qihai[CV6], Shimen[CV5], Guanyuan[CV4]); left thoroughfare vessel (left Huangshu[KI16], left Zhongzhu[KI15], left Siman[KI14], left Qixue[KI13], left Dahe[KI12], left Henggu[KI11]); left stomach meridian (left Tianshu[ST25], left Wailing[ST26], left Qichong[ST30]); left spleen meridian (left Daheng[SP15], left Fujie[SP14]); right thoroughfare vessel (right Huangshu[KI16], right Zhongzhu[KI15], right Siman[KI14], right Qixue[KI13], right Dahe[KI12], right Henggu[KI11]); right stomach meridian (right Wailing[ST26], right Daju[ST27], right Shuidao[ST28], right Guilai[ST29], right Qichong[ST30]); and right spleen meridian (right Fujie[SP14]). The area under the ROC curve of conception vessel (Yinjiao[CV7], Qihai[CV6], Shimen[CV5], Guanyuan[CV4]), thoroughfare vessel (right Siman[KI14], left Huangshu[KI16], right Qixue[KI13], right Zhongzhu[KI15], right Dahe[KI12], left Zhongzhu[KI15], left Siman[KI14], right Huangshu[KI16], left Qixue[KI13], right Henggu[KI11], left Henggu[KI11], left Dahe[KI12]); stomach meridian (left Tianshu[ST25], right Guilai[ST29], left Wailing[ST26], right Shuidao[ST28], right Daju[ST27], right Wailing[ST26], right Qichong[ST30], left Qichong[ST30]), and spleen meridian (left Daheng[SP15], left Fujie[SP14], right Fujie[SP14]) was 0.610-0.682 (P<0.05). Compared with the control group, the sensitization rate of some acupoints in the primary dysmenorrhea group increased (P<0.05). Conclusion With the onset of menstruation, the blood flow perfusion of some acupoints in the abdomen (thoroughfare, and conception vessels, and stomach and spleen meridians) of patients with primary dysmenorrhea and cold blood coagulation and blood stasis syndrome increased, and the status of acupoints changed from a resting state to an active state. These acupoints are sensitive in patients with primary dysmenorrhea and cold blood coagulation and blood stasis syndrome and have a certain diagnostic efficacy, providing a basis for further analyzing the efficacy and mechanism of acupuncture and moxibustion to treat primary dysmenorrhea with cold blood coagulation and blood stasis syndrome.

Objective To evaluate the effects of high-fat diet on the pharmacokinetics of metronidazole in Chinese healthy adult subjects.Methods This program is designed according to a single-center,randomized,open,single-dose trial.Forty-seven healthy subjects were assigned to receive single dose of metronidazole tablets 200 mg in either fasting and high-fat diet state,and blood samples were taken at different time points,respectively.The concentrations of metronidazole in plasma were determined by high performance liquid chromatography-mass spectromentry.Results The main pharmacokinetic parameters of metronidazole in fasting state and high-fat diet state were as follows:Cmax were(4 799.13±1 195.32)and(4 044.17±773.98)ng·mL-1;tmax were 1.00 and 2.25 h;t1/2 were(9.11±1.73)and(9.37±1.79)h;AUC0_t were(5.59±1.19)x 104 and(5.51±1.18)x 104 ng·mL-1·h;AUC0_∞ were(5.79±1.33)x 104 and(5.74±1.32)× 104 ng·mL-1·h.Compared to the fasting state,the tmaxof the drug taken after a high fat diet was delayed by 1.25 h(P＜0.01),Cmax,AUC0_t,AUC0-∞ were less or decreased in different degrees,but the effects were small(all P＞0.05).Conclusion High-fat diet has little effects on the pharmacokinetic parameters of metronidazole,which does not significantly change the degree of drug absorption,but can significantly delay the time to peak.

Objective To evaluate the bioequivalence of metronidazole tablet and reference formulation in Chinese healthy subjects.Methods A single-dose,two-cycle,randomized,open,self-crossover trial was designed with 48 healthy subjects randomly assigned to fasting or postprandial group.For each group,a single oral dose of metronidazole tablet(200 mg)or a reference preparation(200 mg)per cycle were enrolled.The concentration of metronidazole in plasma was measured by high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).The non-compartmental model was applied to calculate the pharmacokinetic parameters for bioequivalence analysis via SAS 9.3 software.Results The main pharmacokinetic parameters of test and reference metronidazole tablets in the fasting group were as follows,the Cmax were(4 855.00±1 383.97)and(4 799.13±1 195.32)ng·h·mL-1;the AUC0-t were(54 834.68±12 697.88)and(55 931.35±11 935.28)ng·h·mL-1;the AUC0-∞ were(56 778.09±13 937.76)and(57 922.83±13 260.54)ng·h·mL-1;the Tmax were respectively 1.17 and 1.00 h;t1/2 were(8.99±1.76)and(9.11±1.73)h,respectively.The ratio of the geometric mean and its 90％confidence intervals(CI)of Cmax,AUC0-t and AUC0-∞ were all within the equivalent interval of 80.00％-125.00％.As for postprandial conditions,the main pharmacokinetic parameters of test and reference metronidazole tablets were as follows,the Cmax were(4 057.08±655.08)and(4 044.17±773.98)ng·h·mL-1;the AUC0-t were(55 956.42±12 228.12)and(55 121.04±11 784.55)ng·h·mL-1;the AUC0-∞ were(58 212.83±13 820.00)and(57 350.38±13 229.46)ng·h·mL-1;the Tmax were 2.50 and 2.25 h;the t1/2 were(9.37±1.68)and(9.37±1.79)h,respectively.The ratio of the geometric mean and 90％CI of Cmax,AUC0-t and AUC0-∞ were all within the equivalent interval of 80.00％-125.00％.Conclusion The two preparations were bioequivalent to Chinese healthy adult volunteers under both fasting and fed conditions.

【Objective】 To explore the feasibility of using autologous platelet-rich plasma (PRP) in the treatment of deep second-degree burns complicated with wound infection. 【Methods】 A retrospective analysis was conducted on the treatment process of a patient with deep second-degree burns and bacterial infection on the wound using autologous PRP. Clinical treatment highlights and outpatient follow-up were combined to discuss the feasibility and clinical effects of using autologous PRP in the treatment of burn wounds complicated with infection. 【Results】 The patient had a deep second-degree burn with a coagulase-negative Staphylococcus infection on the left lower limb. After one week of conventional wound dressing and antibiotic treatment, the patient's body temperature returned to normal. However, wound healing was slow and yellow secretion persisted. Subsequently, the burn wound was treated combined with topical autologous PRP. The wound pain score gradually decreased from 8 to 1. After 2 weeks, the bacterial culture of the wound secretion was negative, and the wound healed completely after 18 days. The wound scar score decreased from 5 to 2 at 1, 3 and 6 months after PRP treatment, and no obvious scar formation was observed. In the course of PRP treatment, there were no adverse reactions such as increased wound inflammation, abnormal blood routine and liver and kidney function test results. 【Conclusion】 For deep second-degree burn patients with localized wound bacterial infections who either refuse surgery or are not suitable for surgery, autologous PRP is a safer alternative that can effectively promote tissue regeneration and wound healing. The patient in this case achieved a curative effect in a short period of time.

Objective:To evaluate the efficacies of intravenous immunoglobulin (IVIG) in the clearance of Bovine Kobu (BK) virus and treatment of BK virus nephropathy (BKVN) in kidney transplantation recipients.Methods:From March 1, 2018 to March 31, 2022, the relevant clinical data were retrospectively reviewed for 13 kidney transplantation recipients with histologically proven BKVN on a full course of IVIG. The changes of serum creatinine and glomerular filtration rate (GFR) were compared before and after Month 1/3/6/12. Univariate Cox regression analysis was performed for examining the overall risk factors of BK virus clearance failure.Results:kidney transplantation (12 cases) and combined pancreatorenal transplantation (1 case) were performed. Among them, 9/13 patients were pathologically classified as stage A (early changes without tubular necrosis) and another 4 cases as stage B (active nephropathy with viral tubular necrosis). After IVIG dosing, all patients with BK virus in blood turned negative. Urinary BK virus DNA load of 7 patients with BK virus declined by 10 3 copies/ml, and 6 patients with BK virus in urine turned negative. Blood BK viral DNA load, urinary BK viral DNA load, GFR and serum creatinine before IVIG were 26 100 (1 000, 254 000) copies /ml and 1 450 (438, 7 480) ×10 6 copies /ml, (35. 36±14. 57) ml/min and (208. 50±66. 89) μmol/L, respectively, after 12 months of use of IVIG were 0、0(0, 0. 58) ×10 6 copies/ml、(46. 05±13. 00) ml/min and(175. 38±50. 64) μmol/L, the differences were statistically significant ( P=0. 012, 0. 027, 0. 046 and 0. 039) . Univariate Cox regression analysis showed that the overall risk factor for viral clearance failure was high initial viral load ( HR=0. 780, 95% CI: 0. 64-0. 98, P=0. 032) , concurrent transplanted kidney rejection ( HR=0. 847, 95% CI: 0. 52-0. 93, P=0. 013) and higher BKVN grade ( HR=0. 426, 95% CI: 0. 22-0. 81 , P=0. 010) were the overall risk factors for urinary BK virus clearance failure. No major adverse events occurred. Conclusions:IVIG may achieve a high efficacy of BK virus clearance. IVIG is effective in the treatment of BKVN. The graft renal function was stable or improved after treatment.

Objective:To develop a robotic digestive endoscope system (RDES) and to evaluate its feasibility, safety and control performance by experiments.Methods:The RDES was designed based on the master-slave control system, which consisted of 3 parts: the integrated endoscope, including a knob and button robotic control system integrated with a gastroscope; the robotic mechanical arm system, including the base and arm, as well as the endoscopic advance-retreat control device (force-feedback function was designed) and the endoscopic axial rotation control device; the control console, including a master manipulator and an image monitor. The operator sit far away from the endoscope and controlled the master manipulator to bend the end of the endoscope and to control advance, retract and rotation of the endoscope. The air supply, water supply, suction, figure fixing and motion scaling switching was realized by pressing buttons on the master manipulator. In the endoscopy experiments performed on live pigs, 5 physicians each were in the beginner and advanced groups. Each operator operated RDES and traditional endoscope (2 weeks interval) to perform porcine gastroscopy 6 times, comparing the examination time. In the experiment of endoscopic circle drawing on the inner wall of the simulated stomach model, each operator in the two groups operated RDES 1∶1 motion scaling, 5∶1 motion scaling and ordinary endoscope to complete endoscopic circle drawing 6 times, comparing the completion time, accuracy (i.e. trajectory deviation) and workload.Results:RDES was operated normally with good force feedback function. All porcine in vivo gastroscopies were successful, without mucosal injury, bleeding or perforation. In beginner and advanced groups, the examination time of both RDES and ordinary endoscopy tended to decrease as the number of operations increased, but the decrease in time was greater for operating RDES than for operating ordinary endoscope (beginner group P=0.033; advanced group P=0.023). In the beginner group, the operators operating RDES with 1∶1 motion scaling or 5∶1 motion scaling to complete endoscopic circle drawing had shorter completion time [1.68 (1.40, 2.17) min, 1.73 (1.47, 2.37) min VS 4.13 (2.27, 5.16) min, H=32.506, P<0.001], better trajectory deviation (0.50±0.11 mm, 0.46±0.11 mm VS 0.82±0.26 mm, F=38.999, P<0.001], and less workload [42.00 (30.00, 50.33) points, 43.33 (35.33, 54.00) points VS 52.67 (48.67, 63.33) points, H=20.056, P<0.001] than operating ordinary endoscope. In the advanced group, the operators operating RDES with 1∶1 or 5∶1 motion scaling to complete endoscopic circle drawing had longer completion time than operating ordinary endoscope [1.72 (1.37, 2.53) min, 1.57 (1.25, 2.58) min VS 1.15 (0.86, 1.58) min, H=13.233, P=0.001], but trajectory deviation [0.47 (0.13, 0.57) mm, 0.44 (0.39, 0.58) mm VS 0.52 (0.42, 0.59) mm, H=3.202, P=0.202] and workload (44.62±21.77 points, 41.24±12.57 points VS 44.71±17.92 points, F=0.369, P=0.693) were not different from those of the ordinary endoscope. Conclusion:The RDES enables remote control, greatly reducing the endoscopists' workload. Additionally, it gives full play to the cooperative motion function of the large and small endoscopic knobs, making the control more flexible. Finally, it increases motion scaling switching function to make the control of endoscope more flexible and more accurate. It is also easy for beginners to learn and master, and can shorten the training period. So it can provide the possibility of remote endoscopic control and fully automated robotic endoscope.

【Objective】 To explore the feasibility of en-bloc resection of bladder tumors by flexible cystoscope combined with laparoscopic instruments through urethra and to provide reference for the clinical application of this technique. 【Methods】 Self-designed and processed transurethral single-hole PORT and Olympus electronic cystoscope were used as observation mirror; Φ1.8 mm soft grasper, tissue scissors, electric hook, and ultrasonic scalpel were used as instruments; the porcine bladder was used as a model.The PORT was placed through the urethra, and the cystoscope was inserted to observe the inner wall of the bladder and the condition of the mucosa.After the lesion site was identified in the bladder cavity, the soft grasper was inserted to pull the mucosa to be removed, which was then fixed with tension at the target position to maintain a satisfactory feild of view.The surgeon held the cystoscope in the left hand, and operated the laparoscopic instruments into the bladder cavity through the PORT with the right hand.Observing with the cystoscope and lifting and pulling the mucosa with the grasper, the surgeon simulated the cutting and pushing actions to realize the en-bloc resection of the lesioned mucosa. 【Results】 The mucosa at 4 different locations were successfully resected on 2 in vitro porcine bladder models. 【Conclusion】 The in vitro experiments show that the combination of flexible electronic cystoscope and laparoscopic instruments achieves synergistic effects in en-bloc resection of bladder tumor by transurethral single-hole laparoscope without additional iatrogenic bladder injury caused by percutaneous bladder incision.This method is feasible in the treatment of bladder tumors, and has the potential of clinical application after further optimization.

BACKGROUND:The lower cervical vertebral pedicle is the main stress site of the posterior column of the spine,which is of great significance for the maintenance of the stability of the human center of gravity and the reduction of shock.At present,there are few reports on the characteristics of the internal bone trabeculae,and the characteristics of the joint site of the vertebral pedicle with the articular process and the vertebral body.It is urgent to understand the fine anatomical structure of the vertebral pedicle and the relationship and function of each part. OBJECTIVE:To observe the microanatomical morphology of the vertebral pedicle by Micro-CT scanning of cervical vertebra specimens,and to measure and analyze the microstructure and morphometric parameters of the bone trabecula in the cervical pedicle under normal conditions to evaluate the safety performance of the cervical spine. METHODS:Micro-CT scanning was performed on 31 sets of cervical vertebrae C3-C7.By checking and reconstructing the areas of interest in the bone trabecular within the vertebral pedicle,the morphological characteristics and distribution direction of the bone trabecular within the cervical pedicle were observed,and the bone microstructure parameters were detected,and the differences in the bone microstructure of the C3-C7 vertebral pedicle were analyzed and compared. RESULTS AND CONCLUSION:(1)The Micro-CT images showed that the honeycomb bone trabeculae of the pedicle of the lower cervical spine presented a complex network of microstructures.The trabeculae near the cortical bone were lamellar and relatively compact,extending forward toward the vertebral body and backward toward the articular process lamina.Abatoid bone trabeculae extended into the medullary cavity and transformed into a network structure,and then into rod-shaped bone trabeculae.The rod-shaped bone trabeculae were sparsely distributed in the medullary cavity.(2)Statistical results of morphological parameters of bone trabeculae showed that bone volume fraction values in C4 and C5 were higher than that in C7(P＜0.05).The bone surface/bone volume value in C7 was higher than that in C3,C4 and C6(P＜0.05).The bone surface density of bone trabeculae in C7 was higher than that in C3,C4,C5 and C6(P＜0.05).Trabecular thickness in C7 was higher than that in C3,C4 and C5(P＜0.05).Bone surface/bone volume and bone surface density of the left pedicle bone trabecular were greater than those on the right side(P＜0.05).(3)The microstructural changes of C3-C7 were summarized,in which the load capacity and stress of the C7 pedicle were poor,and the risk of injury was high in this area.