[Effects of applying human umbilical cord mesenchymal stem cell exosomes through different pathways to treat full-thickness skin defect wounds in mice]

Objective: To investigate the effects of human umbilical cord mesenchymal stem cell (hUCMSC) exosomes in the treatment of full-thickness skin defect wounds in mice through local wound application, subcutaneous injection at the wound margin, and tail vein injection, and to explore the optimal administration route of hUCMSC exosomes for wound treatment. Methods: This study was an experimental study. hUCMSC exosomes were extracted from the discarded umbilical cord tissue of three normal delivery women aged 25-35 years in the Department of Obstetrics and Gynecology of Baogang Hospital of Inner Mongolia and successfully identified. Totally 120 male BALB/c mice aged 6-8 weeks were selected, and full-thickness skin defect wounds were prepared on the back of them. According to the random number table, the injured mice were divided into control group (without drug administration), local wound application group, wound margin subcutaneous injection group, and tail vein injection group (with 30 mice in each group). Mice in the latter three groups were given 0.2 mL phosphate buffer solution containing 200 μg hUCMSC exosomes by local wound application, subcutaneous injection at the wound margin, and tail vein injection, respectively. On post injury day (PID) 7, 14, and 21, the general condition of the wound was observed, and the wound healing rate was calculated; the wound tissue was collected, the pathological changes and collagen fibers were observed respectively by hematoxylin-eosin staining and Masson staining, the number of new microvessels was observed by CD31 immunohistochemical staining, and the content of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) was detected by enzyme-linked immunosorbent assay. The sample number was 10 in each group at each time point. Results: On PID 7, 14, and 21, the wounds of mice in the 4 groups all healed gradually, and the wound healing of the mice in wound margin subcutaneous injection group was the best; the wound healing rates of mice in the three administration groups were significantly higher than those in control group (P<0.05), the wound healing rates of mice in wound margin subcutaneous injection group and tail vein injection group were significantly higher than those in local wound application group (P<0.05), and the wound healing rates of mice in wound margin subcutaneous injection group were significantly higher than those in tail vein injection group (P<0.05). On PID 7, 14, and 21, the growth and epithelialization speed of the wound tissue of mice in the three administration groups were significantly accelerated, and the collagen fibers in the wounds of mice in the three administration groups were larger in number and more neatly arranged in comparison with the control group. On PID 7, 14, and 21, under every 200-fold visual field, the number of new microvessels in the wound tissue of mice in local wound application group was 24.1±2.5, 50.7±4.1, and 44.2±2.3, respectively, the number of new microvessels in the wound tissue of mice in wound margin subcutaneous injection group was 32.2±2.9, 67.5±4.9, and 53.6±3.7, respectively, and the number of new microvessels in the wound tissue of mice in tail vein injection group was 27.8±2.4, 59.1±3.7, and 49.6±2.6, respectively, which was significantly more than 20.6±1.7, 46.7±3.4, and 40.9±2.8 in control group (P<0.05); the number of new microvessels in the wound tissue of mice in wound margin subcutaneous injection group and tail vein injection group was significantly more than that in local wound application group (P<0.05); the number of new microvessels in the wound tissue of mice in wound margin subcutaneous injection group was significantly more than that in tail vein injection group (P<0.05). On PID 7, 14, and 21, the content of TNF-α and IL-6 in the wound tissue of mice in the three administration groups was significantly less than that in control group (P<0.05), the content of TNF-α and IL-6 in the wound tissue of mice in wound margin subcutaneous injection group and tail vein injection group was significantly less than that in local wound application group (P<0.05), and the content of TNF-α and IL-6 in the wound tissue of mice in wound margin subcutaneous injection group was significantly less than that in tail vein injection group (P<0.05). Conclusions: Local wound application, subcutaneous injection at the wound margin, and tail vein injection of hUCMSC exosomes can all promote the wound healing of full-thickness skin defects in mice through alleviating excessive inflammatory response and promoting angiogenesis. Among them, subcutaneous injection at the wound margin has a better therapeutic effect, indicating subcutaneous injection at the wound margin is the optimal administration route for hUCMSC exosomes in wound treatment.

RGS7 silence protects palmitic acid-induced pancreatic β-cell injury by inactivating the chemokine signaling pathway

Impaired insulin secretion due to pancreatic β-cell injury is an important cause of type 2 diabetes (T2D). Regulators of guanine nucleotide binding protein (G protein) signaling proteins played a key role in regulating insulin sensitivity in vivo. To explore the role of RGS7 on palmitic acid-induced pancreatic β-cell injury, pancreatic β-cells Beta-TC-6 and Min6 were treated with palmitic acid (PA) to similar type 2 diabetes (T2D) injury in vitro. The 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry were used to analyze cell viability, proliferation, and apoptosis, respectively. Enzyme-linked immunosorbent assay (ELISA) kits were used to analyze the changes of inflammation-related cytokines. The expression of gene and protein was measured by quantitative real-time PCR (qRT-PCR) and western blot. PA modeling induced apoptosis, increased levels of inflammation-related cytokines, and suppressed cell viability and proliferation of pancreatic β-cells. RGS7 silence markedly alleviated the cell injury induced by PA. RGS7 overexpression further aggravated apoptosis and inflammatory response in PA-induced pancreatic β-cells and inhibited cell viability and proliferation. It is worth noting that RGS7 activated the chemokine signaling pathway. Silence of the key gene of the chemokine signaling pathway could eliminate the negative effect of RGS7 on PA-induced pancreatic β-cells. RGS7 silence protects pancreatic β-cells from PA-induced injury by inactivating the chemokine signaling pathway.

[Establishment and validation of a risk prediction model for disseminated intravascular coagulation patients with electrical burns]

Objective: To establish and validate a risk prediction model of disseminated intravascular coagulation (DIC) by the screening independent risk factors for the occurrence of DIC in patients with electrical burns. Methods: The retrospective case series study was conducted. The clinical data of 218 electrical burn patients admitted to Baogang Hospital of Inner Mongolia from January 2015 to January 2023 who met the inclusion criteria were collected, including 198 males and 20 females, with the age of (38±14) years. The patients were divided into DIC group and non DIC group based on whether they were diagnosed with DIC during the treatment period. The following data of patients of two groups were collected and compared, including age, gender, total burn area, full-thickness burn area, injury voltage, whether osteofascial compartment syndrome occurred within 1 day after injury, duration of stay in burn intensive care unit, total length of hospital stay, whether combined with inhalation injury and multiple injuries, whether shock occurred upon admission, the abbreviated burn severity index score, and the acute physiology and chronic health evaluation Ⅱ score. The laboratory examination data of the patients within 24 hours after admission were also collected, including blood routine indexes: white blood cell count (WBC), hemoglobin level, platelet count (PLT), and neutrophil count; coagulation indexes: activated partial thromboplastin time (APTT), prothrombin time, thrombin time, and levels of D-dimer and fibrinogen (FIB); blood biochemistry indexes: aspartic transaminase, alanine transaminase, direct bilirubin, total bilirubin, total protein, albumin, blood glucose, creatinine, and urea nitrogen; blood gas analysis indexes: blood pH value, arterial partial pressure of oxygen, arterial partial pressure of carbon dioxide, bicarbonate, and base excess; and cardiac zymogram indexes: levels of myoglobin, troponin, lactate dehydrogenase, creatine kinase (CK), and α-hydroxybutyrate dehydrogenase. Data were statistically analyzed with chi-square test, Fisher's exact probability test, independent sample t test, and Mann-Whitney U test. For the variables with statistically significant differences in single factor analysis, the least absolute value selection and shrinkage operator (LASSO) regression was used to reduce the dimension, and the predictive factors for DIC in 218 patients with electrical burns were screened. The above-mentioned predictors were included in multivariate logistic regression analysis to find out the independent risk factors for DIC in 218 patients with electrical burns, and to draw the prediction model nomograms. The performance of the prediction model was evaluated by the receiver operating characteristic (ROC) curve and the area under the ROC curve, and the prediction model was validated by the calibration curve and clinical decision curve analysis (DCA). Results: Compared with those in non DIC group, the total burn area, full-thickness burn area, total length of hospital stay, and the proportions of high voltage caused injury, occurrence of osteofascial compartment syndrome within 1 day after injury, combination of inhalation injury, and occurrence of shock upon admission of patients in DIC group were significantly increased/prolonged (with Z values of -2.53, -4.65, and -2.10, respectively, with χ2 values of 11.46, 16.00, 7.98, and 18.93, respectively, P<0.05). Compared with those in non DIC group, the APTT, level of D-dimer, myoglobin, WBC, PLT, and levels of FIB, total bilirubin, and CK of patients within 24 hours after admission in DIC group were significantly prolonged/increased (with Z values of -2.02, -4.51, and -3.82, respectively, with t values of -3.84, -2.34, -2.77, -2.70, and -2.61, respectively), and the level of total protein and blood pH value were significantly reduced (t=-2.85, Z=-2.03), P<0.05. LASSO regression analysis was carried out for the above 17 indicators with statistically significant differences. The results showed that injury voltage, the occurrence of shock upon admission, the occurrence of osteofascial compartment syndrome within 1 day after injury, and levels of D-dimer and total protein within 24 hours after admission were predictive factors for the occurrence of DIC in 218 patients with electrical burns (with regression coefficients of 0.24, 0.52, 0.35, 0.13, and -0.001, respectively). Multivariate logistic regression analysis showed that injury voltage, the occurrence of shock upon admission, the occurrence of osteofascial compartment syndrome within 1 day after injury, and D-dimer level within 24 hours after admission were independent risk factors for DIC in 218 patients with electrical burns (with odds ratios of 3.33, 4.24, 2.68, and 1.38, respectively, with 95% confidence intervals of 1.43-7.79, 1.78-10.07, 1.17-6.13, and 1.19-1.61, respectively, P<0.05). Based on the aforementioned four independent risk factors, the nomogram of prediction model for evaluating the probability of DIC in patients was drawn. The area under the ROC curve of prediction model was 0.88, and the 95% confidence interval was 0.82-0.95, indicating that the model had good predictive ability; the curve of prediction model tended to be near the ideal curve, indicating that the model had a high calibration degree; the clinical DCA of prediction model showed that the threshold probability of patients ranged from 4% to 97%, indicating that the model had good predictive ability. Conclusions: The injury voltage, the occurrence of shock upon admission, the occurrence of osteofascial compartment syndrome within 1 day after injury, and D-dimer level within 24 hours after admission are independent risk factors for the occurrence of DIC in patients with electrical burns. The prediction model established based on the above indicators can provide early warning for the occurrence of DIC in these patients.

[Research advances of natural biomaterials in promoting wound repair]

Acute and chronic wounds seriously threaten patients' life health and quality of life, therefore, wound repair has become a hot topic of research for scholars at home and abroad in recent years. With the development of material science and tissue engineering, more and more biomaterials prepared from natural ingredients were used in basic research and clinical treatment of wound repair. Such biomaterials can be used as templates for wound tissue regeneration to induce autologous cell adhesion and migration, and promote the deposition of extracellular matrix, which have broad clinical application prospects. This paper reviews the characteristics and application advance of natural biomaterials which are popular in the field of wound repair, aiming to provide ideas for the research and development of new wound dressing and tissue engineering skin.

[Clinical effects of ultra-pulsed fractional carbon dioxide laser in the treatment of mild to moderate microstomia after burns]

Objective: To investigate the clinical effects of ultra-pulsed fractional carbon dioxide laser (UFCL) in the treatment of mild to moderate microstomia after burns. Methods: A retrospective observational study was conducted on 19 patients with mild to moderate microstomia after burns who were admitted to Inner Mongolia Baogang Hospital from January 2018 to January 2022, including 15 males and 4 females aged (35±14) years. Patients had an average course of 71 d of microstomia, with 8 cases of moderate microstomia and 11 cases of mild microstomia. All the patients received UFCL treatment every 2-3 months until the microstomia was corrected or the treatment bottleneck was reached. The times of UFCL treatment for patients and the time interval from the last treatment to the last follow-up were recorded. Before the first treatment and at the last follow-up, the opening degree of mouth (finger measurement method), oral gap width, and the distance between the upper and lower incisors during mouth opening were recorded. Before the first treatment and at the last treatment, the new Vancouver scar scale (VSS) was used to evaluate the scar. At the last follow-up, the degree of satisfaction was evaluated by the Likert 5 scale by the patients themselves, and the satisfaction ratio was calculated; the adverse reactions such as pigmentation, blisters, infection, and persistent erythema in the treatment area were counted. Data were statistically analyzed with Mann-Whitney rank sum test or paired sample t test. Results: Patients received UFCL treatment of 3 (2, 6) times. The interval from the last treatment to the last follow-up was 26 months at most and 4 months at least. At the last follow-up, the opening degree of mouth of patients was significantly improved than that before treatment (Z=4.68, P<0.01). At the last follow-up, the oral gap width of patients was (35±6) mm, and the distance between upper and lower incisors during mouth opening was (3.2±0.4) cm, which was significantly improved compared with those before treatment (with t values of 10.73 and 18.97, respectively, P<0.01). The VSS score after the last treatment was 4.1±1.6, which was significantly better than that before treatment (t=22.96, P<0.01). At the last follow-up, the satisfaction ratio of patients with treatment was 18/19, and no pigmentation, blisters, infection, persistent erythema, and other adverse reactions of all patients in the treatment area occurred, however, one of the patients reported that the disease recurred about half a year after treatment. Conclusions: UFCL is an effective method for treating mild to moderate microstomia after burns, with which patients are highly satisfied, and it is worth of further study and promotion.

Design of unmanned interaction system based on visual cognition

The stability of unmanned vehicle is related to the safety of the vehicle itself. In the process of unmanned vehicle control, there will be collision phenomenon in the process of meeting the vehicle. To solve the above problem, the design of unmanned interaction system based on visual cognition is proposed. The hardware structure of the system is designed based on 80C51 single chip microcomputer, including ARM processor, GPS receiving module, driving record signal collecting module, etc. The PID controller design based on neural network is optimized, and the design of unmanned interactive system based on visual cognition is completed. Experimental results show that the designed system can identify the surrounding environment in real time, make corresponding decisions, let the vehicle avoid the wrong vehicle operation, and save Oil consumption.

[Research advances on signaling pathways affecting sweat gland development and their involvement in the reconstitution of sweat adenoid cells in vitro]

The damage of sweat glands in patients with extensive deep burns results in the loss of thermoregulation, which seriously affects the quality of life of patients. At present, there are many researches on the repair of sweat gland function, but the mechanism of human sweat gland development has not been fully clarified. More and more studies have shown that the cascaded pathways of Wnt/β-catenin, ecto- dysplasin A/ectodysplasin A receptor/nuclear factor-κB, sonic hedgehog, and forkhead box transcription factor jointly affect the development of sweat glands, and it has been reported that the cascaded signaling pathways can be used to achieve the reconstruction of sweat adenoid cells in vitro. This article reviews the signaling pathways that affect the development of sweat glands and their involvement in the reconstruction of sweat adenoid cells in vitro.

Probiotics alleviate adipose inflammation in high-fat diet-induced obesity by restoring adipose invariant natural killer T cells

OBJECTIVE

Invariant natural killer T (iNKT) cells, which are depleted in obese individuals, play important roles in preventing diet-induced obesity and associated disorders. Probiotic supplementation can alter the gut microbiota and immunomodulation in obesity. However, it remains unclear whether probiotics can affect visceral adipose iNKT cells. The aim of this study was to analyze the effects of probiotics on adipose iNKT cells in mice with high-fat diet (HFD)-induced obesity and to assess the immunomodulatory function of probiotics and their role in obesity, glucose tolerance, lipid metabolism, insulin resistance, and adipose inflammation.

METHODS

Wildtype (WT) male C57BL/6 mice and CD1d knockout mice were fed an HFD or a normal-fat diet. Some mice received active or heat-sacrificed VSL#3 probiotics. Preventative VSL#3 therapy was also administered to HFD mice. Body weight, metabolic parameters, expression of genes encoding adipose inflammatory factors (interleukin [IL]-4, IL-10, tumor necrosis factor-α, interferon-γ, and IL-6), adipose iNKT cell frequency, and subphenotype were evaluated.

RESULTS

HFD induced more severe obesity in CD1dKO mice than in WT mice. VSL#3 intervention significantly improved HFD-induced weight gain, adipose iNKT cell depletion, and metabolic and adipose inflammatory profiles in WT mice, but not in CD1dKO mice. Preventative VSL#3 treatment improved HFD-induced obesity and metabolic parameters, and elevated total adipose iNKT and IL-4⁺ iNKT cell frequencies.

CONCLUSIONS

Probiotic intervention alleviated weight gain, improved metabolic parameters, and reduced adipose inflammation in HFD-induced obesity. These effects seem to depend on the restoration of visceral adipose iNKT cells. These findings have potential implications for the management of obesity-related diseases.

[Transplantation of compound tissue flap of toe to reconstruct the thumb with necrosis caused by electric burns in four patients]

From January 2010 to December 2017, 4 patients of thumb with necrosis caused by electric burns (all male, aged from 31 to 58 years) were admitted to our hospital, with 1 patient of second degree injury of right thumb, 2 patients of third degree injury of right thumb, and 1 patient of third degree injury of left thumb. Routine debridement under general anesthesia was performed within 7 days after injury. The compound tissue flap of contralateral second toe was transplanted to reconstruct the thumb with third degree defect, and compound tissue flap of ipsilateral distal hallex was transplanted to reconstruct the thumb with second degree defect. Dorsalis pedics artery was anastomosed with radial artery, saphenous vein or dorsalis pedics vein was anastomosed with cephalic vein. The donor site was transplanted with split-thickness skin graft from autologous thigh. All the tissue flaps and skin grafts survived in 2 weeks after surgery. Within 1 year of follow-up, the reconstructed thumbs can achieve radial abduction and palmar abduction with good function. Reconstruction of thumb with free transplantation of compound tissue flap of toe is a good method to repair thumb with necrosis caused by electric burn.

Numerical and experimental studies of water disinfection in UV reactors

Performance of UV reactors for water disinfection is investigated in this paper. Both experimental and numerical studies are performed on base reactor LP24. Enterobacteria phage MS2 is chosen as the challenge microorganism in the experiments. Experiments are conducted to evaluate the effect of different parameters, i.e. flow rate and UV transmission, on the reactor performance. Simulation is carried out based on the commercial software ANSYS FLUENT with user defined functions (UDFs) implemented. The UDF is programmed to calculate UV dose absorbed by different microorganisms along their flow trajectories. The effect with boundary layer mesh and without boundary layer mesh for LP24 is studied. The results show that the inclusion of boundary layer mesh does not have much effect on the reactor performance in terms of reduction equivalent dose (RED). The numerical results agree well with the experimental measurements, hence validating the numerical model. With this achieved, the numerical model is applied to study other scaled reactors: LP12, LP40, LP60 and LP80. Comparisons show that LP40 has the highest RED and log inactivation among all the reactors while LP80 has the lowest RED and log inactivation.

[Effects of allogeneic mouse adipose-derived mesenchymal stem cell-microporous sheep acellular dermal matrix on healing of wound with full-thickness skin defect in mouse and the related mechanism]

Objective: To explore the allogeneic mouse adipose-derived mesenchymal stem cell (ADSC)-microporous sheep acellular dermal matrix (ADM) on healing of wound with full-thickness skin defect in mouse and the related mechanism. Methods: One Kunming mouse was sacrificed by cervical dislocation to collect adipose tissue from inguinal region. Mouse ADSCs were isolated from the adipose tissue and cultured in vitro. Cells of the third passage were identified by cell adipogenic and osteogenic differentiation. The expressions of CD73, CD90, CD105, and CD34 were analyzed by flow cytometry. After one sheep was sacrificed, microporous sheep ADM was prepared from sheep back using decellularization method and freezing-thawing method. A 12 mm diameter, round, full-thickness skin defect wound was made on the back of each one of 36 Kunming mice. The wounds were covered by microporous sheep ADM. The mice were divided into group ADSC and control (C) group with 18 mice in each group according to the random number table after surgery. A volume of 0.2 mL DMEM/F12 culture medium containing 1×10(6) ADSCs was injected between microporous sheep ADM and wound of mice in group ADSC. While 0.2 mL DMEM/F12 culture medium was injected between microporous sheep ADM and wound of mice in group C. On post surgery day (PSD) 12 and 17, wound healing rates of mice in the 2 groups were calculated. On PSD 7, 12, and 17, wound vascularization of mice in the 2 groups was observed under reverse irradiation of backlight. On PSD 7, 12, and 17, the wound granulation tissue of mice in group ADSC was observed by hematoxylin and eosin staining. On PSD 7, the thicknesses of granulation tissue of mice in the 2 groups was measured. On PSD 12 and 17, expressions of VEGF in wounds of mice in the 2 groups were detected by immunohistochemical method. The sample number was 6 in each group at each time point in the above experiments. Data were processed with t test and analysis of variance of factorial design. Results: (1) After 7 days of adipogenic induction, lipid droplet was observed in cytoplasm using oil red O staining. After 21 days of osteogenic induction, black deposits of calcium salts were detected using silver nitrate staining. Expression rates of CD73, CD90, CD105, and CD34 in cells were 97.82%, 99.32%, 97.35%, and 5.88% respectively. The cells were identified as ADSCs. (2) The wound healing rates of mice in group ADSC on PSD 12 and 17 [(78±6)%, (98±3)%] were significantly higher than those in group C [(60±9)%, (90±4)%, t=4.26, 4.46, P<0.01]. (3) On PSD 7, no vessel obviously grew into the center of wounds of mice in the 2 groups, while the granulation tissue has covered the wounds of mice in group ADSC. On PSD 12, the vessels were more abundant in wounds of mice in group ADSC than those in group C. On PSD 17, big vessels crossing the whole wounds was observed in wounds of mice in group ADSC, while big vessels were observed without crossing the whole wounds in wounds of mice in group C. (4) The wounds were covered with thin granulation tissue on PSD 7, and the granulation tissue began to thicken on PSD 12 and were covered by epidermis on PSD 17 in wounds of mice in group ADSC. On PSD 7, the granulation tissue in wounds of mice in group ADSC [(0.62±0.05) mm] was significantly thicker than that in group C [ (0.31±0.04) mm, t=12.27, P<0.01]. (5) On PSD 12 and 17, expressions of VEGF in wounds of mice in group ADSC [(80.7±2.2), (0.98±0.03)/mm(2)] were significantly than those in group C [(59.5±2.4), (81.5±2.6)/mm(2,) t=15.95, 14.14, P<0.01]. Conclusions: Allogeneic mouse ADSC-microporous sheep ADM can accelerate angiogenesis and growth of granulation tissue, thus promoting wound healing, which may be due to the increase of expression of VEGF.

[Effects of combined application of culture supernatant of human umbilical cord mesenchymal stem cells and ciprofloxacin on Staphylococcus aureus in vitro]

Objective: To explore the effects of combined application of culture supernatant of human umbilical cord mesenchymal stem cells (hUCMSCs) and ciprofloxacin on Staphylococcus aureus (SA) in vitro. Methods: hUCMSCs were isolated from umbilical cord tissue of full-term healthy fetus after cesarean section and cultured. Cells in the third passage were used in the experiments after identification. SA strains isolated from wounds of burn patients in our burn wards were used in the experiments. Cells were divided into 0, 10, 100, and 1 000 ng/mL lipopolysaccharide (LPS) groups according to the random number table (the same dividing method below). Cells were cultured with culture medium of mesenchymal stem cells (MSCs) after being treated with medium containing the corresponding mass concentrations of LPS for 12 h. At post culture hour (PCH) 6, 12, and 24, 6 wells of culture supernatant of cells in each group were obtained to measure the content of LL-37 with enzyme-linked immunosorbent assay. Ninety blood agar plates were divided into ciprofloxacin control group (CC), ciprofloxacin+ supernatant group (CS), and ciprofloxacin+ supernatant+ LL-37 antibody group (CSL), with 30 blood agar plates in each group. Blood agar plates in group CC were coated with 1.5×10(8) colony forming unit (CFU)/mL bacteria solution prepared with normal saline. Blood agar plates in group CS were coated with 1.5×10(8) CFU/mL bacteria solution prepared with normal saline and culture supernatant of hUCMSCs (cultured by culture medium of MSCs, the same below) in double volume of normal saline. Blood agar plates in group CSL were coated with 1.5×10(8) CFU/mL bacteria solution prepared with normal saline, culture supernatant of hUCMSCs in double volume of normal saline, and 2.6 μL LL-37 antibody in the concentration of 2 μg/mL. At PCH 12, 24, and 48, 10 blood agar plates of each group were harvested to observe the distribution of SA colony on blood agar plate and to measure the diameter of bacterial inhibition ring of ciprofloxacin. The minimum inhibitory concentration (MIC) of ciprofloxacin against SA of each group was recorded. Fractional inhibitory concentration (FIC) indexes of ciprofloxacin in groups CS and CSL at PCH 12, 24, and 48 were calculated, and the effect of synergy was evaluated. Data were processed with analysis of variance of factorial design, one-way analysis of variance, LSD-t test, Kruskal-Wallis test, and Mann-Whitney U test. Results: (1) At each PCH, the content of LL-37 in culture supernatant of cells in 10, 100, and 1 000 ng/mL LPS groups was higher than that in 0 ng/mL LPS group (with t values from 11.22 to 33.36, P values below 0.01); the content of LL-37 in culture supernatant of cells in 100 and 1 000 ng/mL LPS groups was higher than that in 10 ng/mL LPS group (with t values from 2.24 to 18.73, P<0.05 or P<0.01); the content of LL-37 in culture supernatant of cells in 1 000 ng/mL LPS group was higher than that in 100 ng/mL LPS group (with t values from 12.46 to 14.70, P values below 0.01). (2) At PCH 12, 24, and 48, the bacterial colonies in groups CC, CS, and CSL began to integrate over time. At PCH 12, 24, and 48, the diameters of bacterial inhibition ring of ciprofloxacin in group CC were 26, 24, and 23 mm, respectively, with no obvious change. At PCH 12, 24, and 48, the diameters of bacterial inhibition ring of ciprofloxacin in groups CS and CSL were 82, 71, 68 mm, and 74, 59, 56 mm, respectively, significantly longer than those of group CC. (3) At each PCH, the MIC of ciprofloxacin against SA was significantly higher in group CC than in groups CS and CSL (with Z values from 6.22 to 6.71, P values below 0.01); the MIC of ciprofloxacin against SA was significantly higher in group CSL than in group CS (with Z values all equal to 6.72, P values below 0.01). (4) FIC indexes of ciprofloxacin in groups CS and CSL at PCH 12, 24, and 48 were 0.011, 0.032, 0.032, and 0.122, 0.350, 0.350, respectively. The results indicated that culture supernatant of hUCMSCs had synergistically antibacterial effect on ciprofloxacin. Conclusions: hUCMSCs can secrete LL-37, and the secretion level is increased with increase of LPS concentration. Combination of culture supernatant of hUCMSCs and ciprofloxacin can decrease the dosage of ciprofloxacin in resisting SA. Once LL-37 is neutralized, the synergistically antibacterial effect of culture supernatant of hUCMSCs is decreased.

A compact two-way power divider based on five-port structure

A novel compact five-port waveguide power divider based on the single-ridge waveguide and three-ridge waveguide structure is proposed. It is realized by the coupling of the TE₁₀ and TE₃₀ modes. At the central coupling section, the single-ridge and three-ridge waveguides are used to constitute the conventional rectangular waveguide to reduce the sectional sizes. It consists of one input port, two output ports, and two isolated ports. For validation, a compact five-port power divider is designed, fabricated, and measured. The measured results show that, from 8 to 9 GHz, the return loss of the input port and output ports is higher than 18 dB, the isolation between the output ports is higher than 15 dB, the insertion loss is less than 0.3 dB, and the amplitude and the phase imbalance between the output ports are less than ±0.05 dB and ±1°, respectively. The simulated results basically agree with the simulations. Its sectional sizes are 1.1 λ × 0.4 λ which are more compact than most of the two-way isolated waveguide power dividers.

[Advances in the research of basic study and clinical application of adipose-derived mesenchymal stem cells]

Since the discovery of adipose-derived mesenchymal stem cell (ADSC) in more than ten years, a great progress has been made from its basic research to clinical application. Compared with bone marrow mesenchymal stem cells, ADSCs are more abundant in reserve, easier to obtain with fewer injuries and less complications. These cells have multiple differentiation potential and can differentiate into adipocytes, chondrocytes and osteoblasts with the influence of different inducing factors. Early studies of ADSCs mainly focused on the ability of multi-directional differentiation, espe-cially on the regeneration of bone defects and cartilage tissue. At present, the researches mainly focus on immunoregulation and paracrine function of ADSCs. Although ADSCs have made a great progress in clinical application, the cell preparation, use pattern, and mechanisms in clinical treatment are not clear. This paper elaborates on these issues.

A novel high power X-band ferrite phase shifter

A novel high power X-band ferrite phase shifter (PS) employing the structure of several waveguides connected in parallel is proposed. Each of the waveguides is a phase shift unit utilizing a dual-toroid structure. First, the phase shift unit is designed, manufactured, and tested. The results indicate that the power capacity reaches 115 kW. At this power, the maximum magnetic field strength of ferrite is 7.9 kA/m, beyond which the nonlinear effect of ferrite will occur. On this basis, the PS that consists of four units connected in parallel is designed. According to the threshold of ferrite, the power capacity of the PS can theoretically reach 430 kW. Limited by the maximum output power of the microwave source, the preliminary high-power test results demonstrate that the PS can operate properly at 270 kW. The PS exhibits an insertion loss of 0.82 dB and a maximum differential phase shift of approximately 300° at 9.3 GHz. The return loss of the PS is more than 16 dB from 9.0 to 9.5 GHz.

A compact five-port waveguide structure and its application as a three-way power divider

A compact five-port waveguide structure consisting of three rectangular ports, one coaxial port, and one circular waveguide port is proposed. The three rectangular waveguides are uniformly distributed in space at angles of 120°, and the coaxial and circular waveguides are located at the top and bottom, respectively, of the rectangular waveguides. The ideal scattering matrix is derived from the symmetry properties of the structure. If the circular and coaxial ports are matched, then the entire five-port waveguide structure is automatically matched. Two connected inserted coaxial probes, a frustum, and a coaxial transition are used to match the five-port waveguide structure with a relatively wide bandwidth. The theoretical and experimental results are generally consistent with each other. With the circular port connected to the load, the five-port waveguide structure becomes a reciprocal TEM mode-to-three-way TE₁₀ mode power divider. Measurements indicate that from 8 to 9.6 GHz, the return losses at the three rectangular ports and the coaxial port are greater than 20 dB and 17 dB, respectively. The isolation among the three rectangular ports is higher than 20 dB. The amplitude and phase imbalances in the division of power are less than 0.1 dB and 2°, respectively. The volume of the five-port waveguide structure is as small as 1.5 λ × 1.5λ × λ.

Cancer in Mali, 1987-1988

Results from the population cancer registry in Bamako, Mali, for the years 1987 and 1988, are presented. The age-standardized incidence for all cancers is high compared with rates reported elsewhere in West Africa (119.6 per 10(5) in males and 88.3 per 10(5) in females), but the leading cancers in each sex are the same (liver cancer in males, cervix cancer in females). The incidence of stomach cancer is the highest recorded in Africa, while rates for lung cancer, although low, exceed those in earlier series from registries in the region.

Acetylcholine receptor antibody in patients with myasthenia gravis

The determination of acetylcholine receptor antibody (AChR Ab) titer by an enzyme-linked immunosorbent assay (ELISA) in patients with myasthenia gravis was introduced. The optimal conditions were determined by chequerboard determination. The specificity was confirmed by inhibition tests. The sensitivity is 9 p mole. The comparison of AChR Ab titers among 49 myasthenic patients, 19 non-myasthenic neurological patients and 20 healthy blood donors has shown that it is a highly sensitive, specific, reproducible, rapid, simple and inexpensive method for determining AChR Ab and that it is highly valuable for the diagnosis of myasthenia gravis.