Viscoelastic properties of decellularized and freeze-dried human dermis between i909c and 40cC.

BACKGROUND: Human donor skin is processed to make the acellular dermis matrix (ADM) for tissue repair and regeneration. There is no data on the viscoelastic properties of ADM at room and subzero temperatures. OBJECTIVE: The work evaluated the temperature dependence of viscoelastic properties of freeze-dried ADM. MATERIALS AND METHODS: Donor skin was de-epidermized, de-cellularized and freeze-dried with trehalose as the lyo-protectant. Glass transition of freeze-dried ADM was measured by differential scanning calorimeter (DSC), and viscoelastic properties were examined by dynamic mechanical analyzer (DMA). RESULTS: At the low moisture range (1.4 +/- 0.5%), the glass transition temperature (Tg) of freeze-dried ADM was 90 degree C to 100 degree C. As the moisture content increased, the Tg decreased steadily. At the high moisture range (10.8 +/- 2.9%), the Tg was 40 degree C to 60 degree C. There were large donor-to-donor variations in viscoelastic properties of freeze-dried ADM as demonstrated by the changes in storage modulus (G'), loss modulus (G") and damping factor tan delta (G"/G'). However, the trends of the temperature dependence for G', G" and tan delta were similar among all 8 donors. For each donor, changes in G' and G" were relatively small between -90 degree C and 40 degree C, and G' was at least one order of magnitude greater than G". Two viscoelastic relaxations were observed in freeze-dried ADM, one at -20 degree C and the other at -60 degree C respectively. CONCLUSION: Freeze-dried ADM was protected in the glassy carbohydrate matrix. DMA observed two viscoelastic relaxations (i.e., alpha process at -20 degree C and beta process at -60 degree C). Overall changes in G' and G'' of freeze-dried ADM were relatively small within one order of magnitude between -90 degree C and 40 degree C. https://doi.org/10.54680/fr24110110612.

[Molecular characteristics and drug susceptibility analysis of Streptococcus agalactiae from respiratory specimen sources].

To study the carriage status of drug susceptibility, clonal complex groups, serotypes, surface proteins and virulence genes of Streptococcus agalactiae from respiratory specimen sources. A total of 35 strains of S.agalactiae meeting the criteria were collected from 3 hospitals in 2 locations, Tangshan and Jinan. The age span of the patients was 3 days-92 years, and the percentage of elderly patients≥60 years was 71.5%.The susceptibility to 9 antimicrobial drugs was measured and analyzed using the micro broth dilution method. The strains were 100.0% sensitive to penicillin, linezolid, vancomycin, and ceftriaxone; However, it exhibits high resistance rates to erythromycin, clindamycin and levofloxacin, at 97.1%, 85.7% and 82.9% respectively; and the resistance rates to tetracycline and chloramphenicol were 34.3% and 14.2%, respectively. Genome sequence determination and analysis showed that 16 resistance genes were detected in 35 strains, among which: macrolide and lincosamide resistance genes were mainly ermB, with a carrying rate of 74.2%; tetracycline resistance genes were mainly tetM, with a carrying rate of 25.7%; in addition, the mutation rates of the quinolone resistance determinants gyrA and parC were 88.5% and 85.7%, respectively. 35 strains belonged to 6 ST types and 4 clonal groups, with CC10/ST10 as the main one, accounting for 62.8%; they contained 4 serotypes of Ⅰb, Ⅱ, Ⅲ, and Ⅴ, as well as 1 untyped strain, with serotype Ⅰb as the main one, accounting for 65.7%. The strains carried three pilus types, PI1+PI2a, PI2a and PI2b types, respectively, and detected five surface proteins, alpha, alp1, rib, srr, and rdf_0594, and seven virulence factors, cba, cfb, cylE, fbsA, hylB, lmb, and pavA. Overall, S.agalactiae isolated from respiratory tract specimens is predominantly sourced from elderly patients, with CC10 strains being most prevalent. These strains harbor multiple drug-resistant and virulence genes, demonstrating elevated resistance rates to macrolides, lincosamides, and quinolones. This emphasizes the necessity for vigilant attention to the health threat posed by S. agalactiae from respiratory tract speciments of elderly patients.

[Overview and inspiration of WHO Guidelines on mental health at work].

The World Health Organization (WHO) released the Guidelines on mental health at work and published a related ILO/WHO joint policy brief with the International Labor Organization (ILO) on September 28th, 2022. They called on governments and employers to adopt supportive interventions in the fields of mental health and occupational health to protect and promote workers' mental health. Based on these two publications, this article summarizes the main ideas of the guidelines, and reviews the relevant legislation progress of China and international level. Besides, it proposes suggestions for formulating occupational safety and health policies, and promoting mental health at work.

[Vaginal microbiota abnormalities in women with unexplained infertility and its treatment].

The vaginal microbiota is a complex and dynamic environment that plays an important role in the healthy reproduction of women. The mechanism of unexplained infertility is not yet clear, and the imbalance and low stability of vaginal microbiota may be related to unexplained infertility. Taking probiotic composite preparations to restore normal vaginal microbiota may be a safe and natural method for treating unexplained infertility. This article reviews the probiotic composite preparations used in the treatment of unexplained infertility both domestically and internationally, including the isolation site of the bacterial species, the use method of the composite preparation, the course of treatment, and the final therapeutic effect, aiming to provide a basis for the clinical application of probiotic composite preparations in the treatment of unexplained infertility.

[Angiopoietin-2 regulates vessels encapsulated by tumor clusters positive hepatocellular carcinoma nest-type metastasis via integrin α5ß1].

Objective: To investigate the molecular mechanism of nest metastasis in blood vessels encapsulated by tumor clusters (VETC) positive hepatocellular carcinoma (HCC). Methods: A total of 72 paraffin embedded HCC tissue samples were collected. Immunohistochemistry staining with CD34 (vascular endothelial cell marker protein) was used to observe the morphological manifestations of VETC cancer nests in primary tumors, bile duct cancerous thrombi and portal vein cancerous thrombi, and to study the characteristics of hematogenous metastasis of VETC cancer nests. Bioinformatics was used to predict the key proteins closely related to VETC cancer nest formation. Immunohistochemistry was used to detect the expression of angiogenin-2 (Ang-2), integrin α5, Integrin ß1, and cyclooxygenase-2 (COX-2) proteins in HCC. Transwell cell migration assay was used to detect the effect of Ang-2/integrin α5ß1 protein on the migration ability of endothelial cells and HCC cells. Western blotting was used to detect the effect of Ang-2/integrin α5ß1 protein on the activity of focal adhesion kinase (FAK) protein. Results: Of the collected HCC specimens, 27 cases (27/72) were VETC (+), including 3 cases with biliary duct cancerous thrombus, 5 cases with portal vein cancerous thrombus, and 3 cases with both biliary duct cancerous thrombus and portal vein cancerous thrombus. VETC (+) HCC could metastasize to portal vein, bile duct, and liver in the form of cancer nest, and the nests retain their intact structure. Ang-2, integrin α5 and integrin ß1 were overexpressed in tumor cells and endothelial cells of VETC (+) HCC nests, while COX-2 was only overexpressed in tumor cells of VETC (+) HCC nest. Ang-2 could promote the migration of HCC cell [(121±12) vs (186±11), P<0.01] and endothelial cells [(81±7) vs (163±14), P<0.01]. Integrin α5ß1 activation antagonist ATN-161 could significantly block the ability of Ang-2 to promote the migration of HCC cells [(185±10) vs (135±9), P<0.05] and endothelial cells [(156±14) vs (103±6), P<0.05]. ATN-161 could significantly block the phosphorylation of FAK in HCC and endothelial cells induced by Ang-2. Conclusions: VETC (+) HCC could metastasize as a whole in a nested form, and possesses a specific regulatory protein. Ang-2/α5ß1/FAK might be potential protein targets in the treatment of VETC (+) HCC nest-type metastasis.

[Study on the expression and roles of nucleolin in cardiac injury in septic mice].

Objective: To explore the expression and roles of nucleolin in cardiac injury in septic mice. Methods: C57BL/6 mice (WT mice) and myocardium-specific expression of nucleolin transgenic mice (TG mice) were randomly divided into sham group (n=10, sham-operated) and sepsis group (n=15, animal model). Cecal ligation and puncture (CLP) was adopted to produce animal models of sepsis. The expression of nucleolin was detected by Western blotting analysis at 0, 12, 24, 48 hours after the operation. The 7-day survival rate, haemodynamic measurement, levels of isoenzyme of creatinekinase-MB (CK-MB) and cardiac troponin I (cTnI) in serum and levels of reactive oxygen species (ROS) and malondlaldehyde (MDA) in myocardium were evaluated 24 hours after the operation. The data were compared between groups with t test. Results: The expression of nucleolin in myocardium up-regulated significantly in WT+CLP group when compared with that in the WT+Sham group(2.57±0.34 vs 1.00±0.15, t=7.468, P<0.01). Compared with those in the WT+Sham group, the survival rate decreased (33.3% vs 100%, χ(2)=13.375, P<0.01), maximal rate of pressure development (+dp/dtmax) declined (t=4.993, P<0.01), but the serum levels of CK-MB and cTnI and the levels of ROS and MDA in myocardium increased in the WT+CLP group(t=5.031, 4.335, 3.365, 2.375, all P<0.05). Compared with that in WT+CLP group, the 7-day survival rate of mice increased in TG+CLP group (60.0% vs 33.3%, χ(2)=8.227, P=0.004), and the cardiac function improved (t=2.337, P=0.019), but the serum levels of CK-MB and cTnI and the levels of ROS and MDA in myocardium in TG+CLP group reduced significantly (t=2.127, 3.347, 2.115, 2.224,P<0.05). Conclusion: The expression of nucleolin is up-regulated in the myocardium of septic mice, and the overexpression of nucleolin can inhibit oxidative stress injury, attenuate the cardiac injury and dysfunction, and reduce mortality in septic mice.

Compound bioengineering protein supplementation improves intestinal health and growth performance of broilers.

Currently, antimicrobial peptides (AMPs) are of growing interest as potential substitutes for antibiotic growth promoters in animal production. The present study was conducted to evaluate the effects of dietary supplementation of bioengineering artificial Parasin I protein (API) and artificial plectasin protein (APL) (named as compound bioengineering protein, CBP) on growth performance and intestinal health of broilers. A total of 450 one-day-old Arbor Acres male healthy broilers were randomly allotted to 5 dietary groups with 10 replicates of 9 individuals in each replicate and supplemented with 0, 250, 500, 750, and 1,000 mg/kg CBP for 6 wk. Dietary CBP supplementation increased (P < 0.01) body weight (6 wk), average daily gain (0-6 wk), and average daily feed intake (3-6 wk and 0-6 wk). CBP addition enhanced antioxidant capacity, which was accompanied by the higher (P < 0.05) activity of serum total antioxidant capacity (T-AOC) (750 mg/kg), jejunal glutathione peroxidase (750 mg/kg), and T-AOC (500 and 1,000 mg/kg). Dietary CBP addition improved intestinal health, reflecting by the increased (P < 0.05) villus height to crypt depth ratio in the duodenum, the upregulated (P < 0.01) mRNA levels of claudin-1 (500 and 750 mg/kg) in the ileum, the downregulated (P < 0.01) mRNA expression of occludin (500 mg/kg) in the duodenum and claudin-1 (500 mg/kg) and occludin (500 and 750 mg/kg) in the jejunum, and the upregulated mRNA expression of (P < 0.01) mucin2 (MUC2) (1,000 mg/kg) in the duodenum. In addition, CBP upregulated (P < 0.01) IL-10 (1,000 mg/kg) in duodenum and ileum, and downregulated (P < 0.05) the mRNA expression of IL-6 (750 and 1,000 mg/kg), interferon-γ (1,000 mg/kg) in the jejunum and TNF-α (250 mg/kg) in the ileum. Furthermore, dietary CBP increased (P < 0.01) the abundance of total bacteria and Lactobacillus (500 and 750 mg/kg), and reduced (P < 0.05) the abundance of Escherichia coli (750 mg/kg) in the cecum. In conclusion, CBP supplementation enhances the antioxidant capacity, intestinal health, immune function, and ameliorates the gut microflora population, thus improving the growth performance of broilers. Dietary supplementation of 750 mg/kg CBP exhibits a better beneficial effect.

[Analysis of factors influencing the success rate of organoid culture in 1231 cases of colorectal cancer].

Objective: To investigate the risk factors for organoid culture failure in colorectal cancer. Methods: This was a retrospective observational study. Tumor specimens were obtained from 1130 patients with colorectal cancer who had undergone surgery or biopsy and had no other concurrent malignancies at Nanfang Hospital of Southern Medical University from December 2021 to November 2022. Organoid culture was performed on 1231 tumor tissue samples. Univariate analysis and multivariate logistic regression were used to analyze the factors that might have influenced the rate of successful organoid culture of colorectal cancer tissue samples. Results: The median (range) duration of organoid culture was 7 (3-12) days. The overall rate of successful culture was 76.3% (939/1231). The rate of successful organoid cultures varied according to the sampling site, malignant ascites having the highest success rate (96.4%, 27/28), followed by liver metastases (83.1%, 54/65), lung metastases (8/10), primary tumors (76.0%, 816/1074), omental metastases (10/14), peritoneal metastases (61.5%, 16/26), ovarian metastases (3/5), and lymph node metastases (5/9). The difference in rates of successful organoid culture between primary tumors and malignant ascites was statistically significant (P=0.012), whereas none of the other rates of successful organoid culture success differed significantly (all P>0.05). The rate of successful organoid culture was 96.4% (27/28) for malignant ascites obtained by abdominal puncture, 76.5% (864/1130) for surgical specimens, and 65.8% (48/73) for endoscopic biopsies; these differences are statistically significant (χ2=10.773, P=0.005). The rate of successful organoid culture was 62.5% (40/64) in the neoadjuvant chemoradiotherapy group, which is significantly lower than in the non-adjuvant (76.9%, 787/1023) and chemotherapy groups (77.8%, 112/144) (χ2=7.134, P=0.028). Multivariate logistic regression analysis revealed that endoscopic biopsy (OR=0.557, 95%CI: 0.335-0.924, P=0.024) and neoadjuvant chemoradiotherapy (OR=0.483, 95%CI: 0.285-0.820, P=0.007) were independent risk factors for failure of organoid culture of colorectal cancer samples. Malignant ascites (OR=8.537, 95%CI:1.154-63.131,P=0.036) and abdominal puncture (OR=8.294, 95% CI: 1.112-61.882, P=0.039) were identified as independent protective factors. Conclusions: The rate of successful organoid culture was influenced by the sampling site, sampling method, and chemoradiotherapy. The rate of successful organoid culture was lower for endoscopic biopsies and in patients receiving preoperative neoadjuvant chemoradiotherapy, and higher for malignant ascites. We consider that culture of malignant ascites is preferable when peritoneal metastases are suspected.

[Anatomical characteristics of profunda artery perforator flap in the posteromedial femoral region and its application in the reconstruction of oral and maxillofacial defects].

Objective: To investigate the anatomical basis for the preparation of the profunda artery perforator flap (PAPF) in the posteromedial femoral region and its application in the reconstruction of oral and maxillofacial defects. Methods: Six lower limbs of Chinese adult cadavers were micro-surgically dissected. CT angiography (CTA) data of bilateral lower limbs of 6 patients was also collected retrospectively. The number, external diameter, pedicle length, and distribution of perforators in the posteromedial femoral region were recorded from the specimens and CTA data. Meanwhile, 10 patients with oral squamous cell carcinoma in the Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University from August 2018 to June 2021 were treated with the PAPF. At each follow-up, contour and function of recipient and donor site, as well as swallowing and speech function were evaluated. Results: A total of 19 profunda artery perforator were identified in 6 lower limb specimens. The outer diameter at the beginning of the source artery was (2.34±0.25) mm and the total length of the pedicle was (11.12±1.06) cm. CTA data analysis of 12 legs identified 15 perforators of profunda artery in the posteromedial region. Eleven perforators were septocutaneous, including 2 perforators with a common trunk, while the remaining 4 perforators were musculocutaneous. As for different patterns of perforators (septocutaneous perforators, musculocutaneous perforators and perforators with a common trunk), the longitudinal distance to the pubic tubercle was (19.95±2.43), (21.84±2.54) and (19.48±0.55) cm respectively. The horizontal distance to the posterior edge of gracilis was (3.54±1.10), (3.72±0.30) and (3.85±1.48) cm, respectively. The initial diameters of perforators was (2.4±0.4), (2.6±0.6) and 1.9 mm respectively. Ten cases of the profunda artery perforator flaps survived successfully after operation. The flap sizes ranged from 8 cm×6 cm to 12 cm×7 cm. The patients were evaluated at 1, 3 and 6 months, and with 6 months interval ever since. During the follow-up, the shape of the recipient site was ideal, and the swallowing and language functions were not significantly affected. There was only linear scar in the donor area, and the function of the thigh was basically normal. Conclusions: PAPF possessed a good anatomic stability, suitable vascular pedicle length and diameter, minor influence to the donor area, sufficient amount tissue with good quality. It is an ideal choice for head and neck reconstruction.

Fluorescence signals of quantum dots influenced by spatially controlled array structures.

Fluorescence signals of quantum dots (QDs) influenced by different array structures of gold-coated silicon nanorods (SiNRs) were investigated via experimental observations and two-dimensional (2D) finite element method (FEM) simulations. On the densest gold-coated SiNRs array structure, the highest QD fluorescence quenching rates were observed and on the sparsest array structure, the highest QD fluorescence enhancement rates were observed. By developing a new technique which obtains the optical image of the array structures without losing information about the QD locations, we were able to further investigate how the QD fluorescence is influenced by spatially controlled array structures.

Antiinflammatory effect of Forsythia suspensa V(AHL) and its active principle.

This study was carried out to elucidate the antiinflammatory active principles obtained from 70% methanol extract of the dried fruit of Forsythia suspensa V(AHL) (F. suspensa). The methanol extract was then partitioned between n-hexane and water, and then the n-hexane fraction was evaporated to dryness under vacuum. The n-hexane fraction was chromatographed (Frs. I--V), Fr. IV was rechromatographed (Frs. VI--VIII), and then Fr. VII was rechromatographed (Frs. IX--XI) by silica gel column chromatography. The antiinflammatory activity of these fractions was investigated on acetic acid-induced vascular permeability in rats. The n-hexane fraction showed an antiinflammatory effect and these activities shifted successively to Fr. IV, Fr. VII and Fr. X. The chemical structure of the active principle obtained from Fr. X was identified as 3beta-acetoxy-20,25-epoxydammarane-24-ol. These results suggest that the antiinflammatory and an analgesic effect of 70% methanol extract of F. suspensa may be the result of the compound that it contains.