[Properties of gelatin-polyethylene glycol hydrogel loaded with silver nanoparticle Chlorella and its effects on healing of infected full-thickness skin defect wounds in mice].

Objective: To explore the properties of gelatin-polyethylene glycol hydrogel loaded with silver nanoparticle (AgNP) Chlorella (hereinafter referred to as the composite hydrogel) and its effects on healing of infected full-thickness skin defect wounds in mice. Methods: The research was an experimental research. The simple gelatin-polyethylene glycol hydrogel (hereinafter referred to as the simple hydrogel) and the composite hydrogel were prepared, and the appearance and injectability of the two hydrogels were observed at 55 and 37 ℃, and under the irradiation of 808 nm near-infrared light, respectively. An electronic universal testing machine was employed to assess the tensile and compressive stress-strain properties of both types of hydrogels at room temperature. Additionally, the cyclic compressive stress-strain properties of the composite hydrogel were examined at 80% of the maximum compressive stress. Staphylococcus aureus or Escherichia coli solution was added to phosphate buffer solution (PBS), simple hydrogel, and composite hydrogel, respectively. The part of composite hydrogel containing Staphylococcus aureus or Escherichia coli solution was irradiated with near-infrared light for 5 minutes. After each sample was incubated for 6 h, the dilution plating method was used to detect and calculate the mortality rates of the two bacteria at 24 h of culture (n=5). The discarded foreskin tissue was taken from a 6-year-old healthy boy admitted to the Department of Urology of the First Affiliated Hospital of Naval Medical University for circumcision. Primary human fibroblasts (HFbs) were isolated using the enzyme extraction method, routinely cultured to the 3rd to 6th passages for subsequent cellular experiments. Composite hydrogel extracts with final mass concentrations of 100.0, 50.0, 25.0, 12.5, and 0 mg/mL were respectively prepared and used to culture HFbs, and the cell proliferation after 24 h of culture was detected using a cell counting kit 8 (n=3). A total of twenty 6-8 weeks old C57BL/6J female mice were utilized, and a full-thickness skin defect was surgically created on the back of each mouse. The wounds were infected with Staphylococcus aureus solution. The infected mice were divided into blank control group, simple hydrogel group, composite hydrogel group, and combined treatment group according to the random number table, and the wounds were treated with PBS, simple hydrogel, composite hydrogel, and composite hydrogel+light irradiation (under the irradiation of 808 nm near-infrared light for 5 min), respectively, with 5 mice in each group. On post injury day (PID) 0 (immediately after the first wound treatment), 3, 7, and 14, an overall assessment of wound exudation and healing were conducted, and the wound healing rates on PID 7 and 14 were calculated (n=5). On PID 14, hematoxylin-eosin staining was performed to observe histopathological changes in the mouse wound. Results: Both simple hydrogel and composite hydrogel were in a solution state at 55 ℃ and transition to a gel state when cooling to 37 ℃. After the two hydrogels were irradiated by near-infrared light, only the composite hydrogel reheated up and returned to the solution state again with injectability. The maximum tensile stress of the composite hydrogel was up to 301.42 kPa, with a corresponding strain of 87.19%; the maximum compressive stress was up to 413.79 kPa, with a corresponding strain of 91.67%, which was similar to the tensile and compressive properties of the simple hydrogel. After 10 compression cycles, the maximum compressive stress of the composite hydrogel still reached 84.1% of the first compressive stress. After 24 h of culture, the mortality rate of Staphylococcus aureus treated with simple hydrogel was significantly higher than that treated with PBS (P<0.05); the mortality rates of Escherichia coli and Staphylococcus aureus treated with composite hydrogel alone were significantly higher than those treated with simple hydrogel (P<0.05); the mortality rates of Escherichia coli and Staphylococcus aureus treated with composite hydrogel+light irradiation were significantly higher than those treated with composite hydrogel alone (P<0.05). After 24 h of culture, compared with that cultured in composite hydrogel immersion solution with final mass concentration of 0 mg/mL, the proliferation activity of HFbs cultured in composite hydrogel immersion solution with final mass concentrations of 25.0 and 50.0 mg/mL was significantly enhanced (P<0.05), while the proliferation activity of HFbs cultured in composite hydrogel immersion solution with final mass concentration of 100 mg/mL was significantly decreased (P<0.05). On PID 0 and 3, more purulent secretions were seen in the wounds of mice in blank control group and simple hydrogel group, while only a small amount of exudate was observed in the wounds of mice in composite hydrogel group, and no obvious infection was observed in the wounds of mice in combined treatment group. On PID 7 and 14, the wound healing rates of mice in simple hydrogel group were significantly higher than those in blank control group (P<0.05); the wound healing rates of mice in composite hydrogel group were significantly higher than those in simple hydrogel group (P<0.05); the wound healing rates in combined treatment group were significantly higher than those in composite hydrogel group (P<0.05). On PID 14, the wounds of mice in blank control group exhibited a high infiltration of inflammatory cells with no new epithelial layer observed; the wounds of mice in simple hydrogel group displayed a short length of newly formed epithelium with a small amount of inflammatory cells; the wounds of mice in composite hydrogel group exhibited continuous formation of new epithelium and a large amount of immature granulation tissue; the wounds of mice in combined treatment group showed continuous epithelialization with less immature granulation tissue. Conclusions: The prepared composite hydrogel exhibits excellent thermosensitivity, photothermal properties, and injectability, as well as excellent mechanical properties, antibacterial properties, and biocompatibility, and can promote the healing of infected full-thickness skin defect wounds in mice.

[Interpretation of group standard for Clostridioides difficile infection diagnosis].

Clostridioides difficile is a key pathogen of antibiotic related diarrhea and hospital associated infection, causing several outbreaks in Europe and North Americans and resulting in severe disease burden. However, the standardized diagnostic principle and detection specifications in C. difficile infection (CDI) survey are limited in China, and the infection rate and disease burden of CDI in China are unclear. Therefore, National Institute for Communicable Disease Control and Prevention,National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, together with another 11 institutions, draft the group standard entitled "Diagnosis of Clostridium difficile infection (T/CPMA 008-2020)" of Chinese Preventive Medicine Association. Based on the principle of "legality, scientificity, advancement, and feasibility", this standard clarifies risk factors, diagnosis principles, diagnoses and differential diagnoses in order to improve the accuracy of CDI diagnosis in clinical practice, guide the surveillance for CDI, and understand the infection rate and disease burden of CDI in China.

Up-regulation of LINC00346 inhibits proliferation of non-small cell lung cancer cells through mediating JAK-STAT3 signaling pathway.

OBJECTIVE: To investigate the expression levels of LINCRNA00346 in tissues and cells in patients with non-small cell lung cancer (NSCLC) and its biological function. PATIENTS AND METHODS: The relative expression levels of LINC 00346 in 70 cases of tissues and cells in NSCLC patients were detected via quantitative reverse transcription polymerase chain reaction (qRT-PCR). The specific interference sequences of LINC 00346 were designed and the transfection efficiency after 48 h was detected. The effect of LINC 00346 on the proliferation capacity of NSCLC cells was studied via cell counting kit-8 (CCK-8) assay. After the interference in LINC 00346 expression in NSCLC cells, the changes in cell cycle and apoptosis were detected via flow cytometry. The nude-mouse transplanted tumor model was established to study the effect of LINC 00346 on in vivo tumorigenic ability of tumor cells. After the interference in LINC 00346 expression, the changes in expressions of molecular markers in the downstream signaling pathway were detected via Western blotting. RESULTS: The LINC 00346 expressions were relatively high in 50 cases of tissues and 5 kinds of tumor cells in NSCLC patients. After the interference in LINC 00346 expression, the apoptosis of tumor cells was promoted, the cell proliferation was inhibited, and the cell cycle was arrested in G1-G0 phase. The animal experiment revealed that the interference in LINC 00346 expression could inhibit the in vivo tumorigenic ability of tumor cells. Western blotting showed that LINC 00346 could exert its function through partially regulating the Janus kinase/signal transducer and activator of transcription 3 (JAK-STAT3) signaling pathway. CONCLUSIONS: The expressions of LINC 00346 were relatively high in NSCLC tissues and cells. LINC 00346 promotes the proliferation and inhibits the apoptosis of NSCLC cells through regulating the JAK-STAT3 signaling pathway.

[Localization and characterization of partial immunodominant antigen epitopes of Trichinella spiralis].

OBJECTIVE: To screen and characterize immunodominant antigen epitopes on the soluble antigens of Trichinella spiralis (T.s.). METHODS: 15 monoclonal antibodies (McAbs) against T.s. muscle larva(ML) soluble antigens were obtained by using hybridoma technique. The reactivity of monoclonal and polyclonal antibodies were tested by ELISA, Western blotting and indirect immunofluorescence assay(IFA). RESULTS: The Western blotting result showed that of the 15 McAbs, 6 could bind to the T.s. ML antigens displaying molecular weights of 40-70 kDa. Polyclonal sera could react with more than 10 bands having molecular weights of 20-200 kDa. Among the 6 McAbs, 4 could recognize epitopes on the cuticle surface and the other two could recognize epitopes on both the cuticle surface and the stichosome. CONCLUSION: The antigen epitopes of T.s. recognized by 6 McAbs had been characterized.

An asynchronous unfolding among molecular different regions of lobster D-glyceraldehyde-3-phosphate dehydrogenase and maltotetraose-forming amylase from an Alcaligenes sp. during guanidine denaturation.

Changes in ultraviolet absorbance and intrinsic protein fluorescence of 1,4-alpha-D-glucan maltotetrahydrolase (EC 3.2.1.60) from an Alcaligenes sp. (Gram-negative bacteria 537.1) and D-glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12) have been compared with their inactivation during denaturation in guanidinium-Cl solutions. The two enzymes were completely inactivated at GuHCl concentrations less than 0.6 M and this was accompanied by marked absorbance and intrinsic fluorescence changes suggesting exposure of aromatic residues. The changes of the intrinsic fluorescence of the amylase have a relatively constant plateau in emission intensities and maxima at GuHCl concentrations from 0.8-2.0 M, similar to that of muscle GAPDH. The relative activity of the enzyme increased markedly in dilute GuHCl solutions accompanied by very little change of its intrinsic fluorescence at 8 degrees C. The kinetic decrease in emission intensities, excited respectively by 230 nm and 292 nm, was different for the two enzymes. The inactivation was a biphasic process with a fast phase faster than the unfolding rate as measured by fluorescence changes in 0.5 M GuHCl solution. Similar to the inactivation process, changes in intensity of 410 nm NAD fluorescent derivative of GAPDH which is in situ at the active site is also a biphasic process under the same condition. It appears that there may be an unfolding intermediate state of the enzymes and an asynchronous unfolding process among the different regions in the molecules during GuHCl denaturation, this may be due to differences in their flexibility.

Central nervous system congenital malformations, especially neural tube defects in 29 provinces, metropolitan cities and autonomous regions of China: Chinese Birth Defects Monitoring Program.

Data from the Chinese Birth Defects Monitoring Program (CBDMP) over the period of October 1986 to September 1987 were analysed to study the descriptive epidemiology of congenital malformations of the central nervous system (CNS), especially neural tube defects (NTDs) in China. A total of 4628 CNS congenital malformations were recorded within seven days of delivery among 1,243,284 live and stillbirths of 28 or more weeks gestation in 945 hospitals from all 29 provinces, metropolitan cities and autonomous regions of China. Neural tube defects account for 73.55% of these cases, hydrocephaly for 24.63% and microcephaly for 1.82%. The prevalence rates at birth of NTDs and congenital malformations of the CNS in China were 27.37 and 37.22 per 10,000 respectively. More NTDs were observed in females (35.68 per 10,000 female births) as compared to males (19.23 per 10,000 male births). The prevalence of NTDs in rural areas (51.69 per 10,000 births) was higher than that in urban areas (15.45 per 10,000 births).

[McAb-ELISA for detection of circulating antigen from schistosoma. I. Preparation, selection of monoclonal antibody and preliminary testing].

Fusions between spleen cells from BALB/c mice infected with Schistosoma japonicum or mansoni cercariae and SP2/0 myeloma were carried out. More than 30 hybridoma cell lines secreting monoclonal antibodies were obtained. Their target antigens were integument, gut and egg respectively. The preliminary tests showed that the antibody against gut-associated polysaccharide antigen had the highest activity of all antibodies obtained. This antibody can be used in the sandwich ELISA to detect trichloroacetic acid soluble antigen at a level of less than 1 ng/ml, A positive reaction was found in a group of infected rabbits, negative in normal and the circulating antigen level correlated with the number of infecting cercariae. Three months after treatment antigen titers of 6/8 rabbits became negative. This report shows that the McAb sandwich ELISA for the detection of circulating antigen is better than other antibody detecting methods. It is also a potential immunodiagnostic method.

[Screening of beta-N-acetylhexosaminidase forming strains and conditions for enzyme production].

About 1200 strains of microorganisms were screened including fungi, actinomyces, and bacteria, in which 237 strains producing the enzyme desired. The results showed that the beta-GlcNAcase and beta-GalNAcase always co-existed in one strain, though may be in different ratio. From strains mentioned above the authors screened out a potent beta-N-acetylhexosaminidase producing strain, Aspergillus tamarii S215, from the soil sample. The optimal conditions for enzyme production were as follows: the microorganisms was inoculated in a 5% wheat bran suspension, cultured at 28-30 degrees C on shaker for 5-6 days. The productivity can be moderately enhanced by the addition of cellobiose or glucosamine or galactosamine or by the extra supplement of (NH4)2SO4 and NH4NO3 as N sources. In the culture filtrate of Asp. tamarii, the alpha, (beta)-galactosidase, beta-glucosidase, alpha-mannosidase and beta-fucosidase were also found.

[Detection of circulating antigen in schistosomiasis by dot-ELISA with monoclonal antibody].

Circulating antigen in sera from acute, chronic and late stages of schistosomiasis patients was detected by direct dot-ELISA with monoclonal antibody 3D8A against schistosome gut-associated cathodic antigen linked with peroxidase, the positive rates being 90.6%, 83.2% and 30.7%, respectively. No positive reactions were found with sera from patients of clonorchiasis, malaria and non-parasitic diseases. The positive rate and the circulating antigen level in EPG greater than 100 group of patients were found to be higher than those in EPG less than 100 group. Circulating antigen became negative one year after praziquantel treatment in 84.0% of patients who showed negative fecal examination, while the other patients remained positive with decreasing titers. The results indicated that the circulating antigen in sera from schistosomiasis patients of various stages can be detected by dot-ELISA with monoclonal antibody 3D8A against circulating schistosome gut-associated cathodic antigen. The authors concluded that the circulating antigen level was correlated with the intensity of infection and the efficacy of treatment.