[Effects of tensile force on the vascular lumen formation in three-dimensional printed tissue].

Objective: To explore the effects of tensile force on vascular lumen formation in three-dimensional printed tissue. Methods: The experimental research method was used. Human umbilical vein endothelial cells (HUVECs) were extracted from discarded umbilical cord tissue of 3 healthy women (aged 22 to 35 years) who gave birth in the Department of Gynaecology and Obstetrics of Suzhou Ruihua Orthopaedic Hospital from September 2020 to May 2021. Human skin fibroblasts (HSFs) were extracted from discarded normal skin tissue of 10 male patients (aged 20 to 45 years) who underwent wound repair in the Department of Hand Surgery of Suzhou Ruihua Orthopaedic Hospital from September 2020 to September 2022. After identification of the two kinds of cells, the 4th to 6th passage of cells were taken for the follow-up experiments. HUVECs and HSFs were used as seed cells, and polycaprolactone, gelatin, hyaluronic acid, and fibrin were used as scaffold materials, and the three-dimensional printed vascularized tissue was created by three-dimensional bioprinting technology. The printed tissue with polycaprolactone scaffold of 6 and 10 mm spacing, and without polycaprolactone scaffold were set as 6 mm spacing polycaprolactone group, 10 mm spacing polycaprolactone group, and non-polycaprolactone group, respectively. After 4 days of culture, the printed tissue in 10 mm spacing polycaprolactone group was selected to detect the cell survival by cell viability detection kit, and the cell survival rate was calculated. After 14 days of culture, the printed tissue in three groups were taken, and the shape change of tissue was observed by naked eyes; immunofluorescence staining was performed to observe the arrangement of filamentous actin, and lumen diameter, total length, and number of branches of vessel in the tissue. The tissue with micro-spring structure in the above-mentioned three groups was designed, printed, and cultured for 9 days, and the tensile force applied in the printed tissue was measured according to the force-displacement curve. The number of samples was all 3 in the above experiments. Data were statistically analyzed with one-way analysis of variance and Tukey test. Results: After 4 days of culture, the cell survival rate in printed tissue in 10 mm spacing polycaprolactone group was (91.3±2.2)%. After 14 days of culture, the shape change of printed tissue in non-polycaprolactone group was not obvious, while the shape changes of printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were obvious. After 14 days of culture, the arrangement of filamentous actin in the printed tissue in non-polycaprolactone group had no specific direction, while the arrangement of filamentous actin in the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group had a specific direction. After 14 days of culture, The vascular lumen diameters of the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were (6.0±1.3) and (10.8±1.3) µm, respectively, which were significantly larger than 0 µm in non-polycaprolactone group (P<0.05), and the vascular lumen diameter of printed tissue in 10 mm spacing polycaprolactone group was significantly larger than that in 6 mm spacing polycaprolactone group (P<0.05); the total length and number of branches of blood vessel in the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were significantly shorter or less than those in non-polycaprolactone group (P<0.05), and the total length and number of branches of blood vessel in the printed tissue in 10 mm spacing polycaprolactone group were significantly shorter or less than those in 6 mm spacing polycaprolactone group. After 9 days of culture, the tensile forces applied in the printed tissue in 6 mm spacing polycaprolactone group and 10 mm spacing polycaprolactone group were (2 340±59) and (4 284±538) µN, respectively, which were significantly higher than 0 µN in non-polycaprolactone group (P<0.05), and the tensile force applied in the printed tissue in 10 mm spacing polycaprolactone group was significantly higher than that in 6 mm spacing polycaprolactone group (P<0.05). Conclusions: The three-dimensional printed scaffold structure can exert different tensile force in the printed tissue, and the vascular lumen diameter of the printed tissue can be regulated by adjusting the tensile force.

[Analysis of influenza vaccination coverage, recommendation behaviors and related factors among health care workers in Nanshan district of Shenzhen city under the free policy between 2019 and 2020].

Objective: To investigate the current situation of influenza vaccination, vaccination willingness, recommended behavior and influencing factors of health care workers (HCWs) under the policy of free vaccination. Methods: A cross-sectional survey was conducted among 3 167 medical staff from 8 hospitals in Nanshan district of Shenzhen city based on a web-based questionnaire platform. The logistic regression was used to analyze the data. Results: The influenza vaccination rate in HCWs was 23.97%, and the recommendation rate was 25.69% from 2019 to 2020. Staff with high professional titles, high academic qualifications, and positive awareness about influenza vaccine had a higher vaccination rate. The main reasons for not recommending influenza vaccine were the fear of patients' misunderstanding of commercial benefits, fear of possible disputes caused by recommended vaccination, lack of national or institutional requirements for recommended influenza vaccine, and fear of adverse reactions of influenza vaccines. Conclusion: Under the free policy, the influenza vaccination rate and recommendation rate of HCWs in Nanshan district of Shenzhen city are relatively low. Strengthening health education on influenza and related knowledge, publicizing the policy of free influenza vaccination, providing convenient vaccination services and promoting the construction of relevant policies and regulations are the key to improve the influenza vaccination rate and recommendation rate among HCWs.

The incidence of breakthrough pain associated with programmed intermittent bolus volumes for labor epidural analgesia: a randomized controlled trial.

BACKGROUND: In this randomized, blinded study, we evaluated the effects of different programmed intermittent epidural bolus (PIEB) volumes for labor analgesia on the incidence of breakthrough pain and other analgesic outcomes. METHODS: Nulliparous women with term cephalic singleton pregnancies who requested labor analgesia had epidural analgesia initiated with 10 mL 0.1% ropivacaine with sufentanil 0.3 µg/mL. The pump was programmed to deliver a 4, 6 or 8 mL bolus every 45 min (groups 4, 6 or 8, respectively). The primary outcome was the incidence of breakthrough pain, defined as inadequate analgesia after two patient-controlled epidural analgesia administrations in a 20-min period. Secondary outcomes included ropivacaine consumption, time of the first patient-controlled epidural analgesia request, duration of the second stage of labor, and incidence of motor block. RESULTS: Among 210 women randomly allocated the incidence of breakthrough pain was 34.9%, 19.7%, and 13.1%, for groups 4, 6 and 8, respectively (P=0.011). The incidence of breakthrough pain in group 8 was lower than in group 4 (P=0.006). The median (interquartile range) hourly ropivacaine consumption was 8.2 mg/h (7.1-11.3), 10.4 mg/h (9.2-13.0), and 12.0 mg/h (11.2-13.8) in groups 4, 6 and 8, respectively (P <0.001). Group 8 had a longer duration of effective analgesia and longer second stage of labor than group 4. There was no significant difference between groups in the incidence of motor block. CONCLUSION: The larger PIEB volumes were preferred for epidural labor analgesia compared with a smaller volume because of improved analgesia without clinically significant increases in adverse effects.

Effects of icariin on the expression of ER, VEGF, and KDR in the endometrial cells of thin endometrium.

We explored the effects of icariin on the expression of estrogen receptor (ER), vascular endothelial growth factor (VEGF), and kinase insert domain receptor (KDR) in the endometrial cells of the thin endometrium. Primary endometrial cells were obtained and divided into a blank control group, a high-, a middle-, and a low-dose icariin groups, as well as an estrogen treatment group to undergo cellular identification by immunocytochemistry. The expression levels of ER, VEGF, and its receptor were estimated by western blotting. The expression levels of ER, VEGF, and KDR gradually increased from the control group to the estrogen (E2) treatment and icariin treatment groups; the differences were statistically significant. However, the differences were not statistically significant among the different icariin dose groups. The endometrium may be thickened by icariin treatment by increasing the expression levels of ER, VEGF, and KDR in endometrial cells.

First Report of Little cherry virus 2 in Flowering and Sweet Cherry Trees in China.

Many viruses infect Prunus spp. and cause diseases on them. During a survey of stone fruit trees in 2008 and 2009, flowering cherry (Prunus serrulata) and sweet cherry (P. avium) trees with foliar chlorosis and reddening, stem deformity, and tree stunting were observed in private orchards in Anning and Fumin counties of Yunnan Province. Some sweet cherry trees with severe symptoms yielded small and few fruits and had to be removed. Leaf samples were collected from 68 flowering cherry and 30 sweet cherry trees, either symptomatic or asymptomatic, from private orchards and community gardens in Kunming and counties Anning, Chenggong, Fumin, Jinning, Ludian and Yiliang. Total nucleic acids were extracted with a CTAB extraction method and tested by reverse transcription (RT)-PCR assay using virus-specific primers. Little cherry virus 2 (LChV-2), Cherry virus A (CVA), Prunus necrotic ringspot virus (PNRSV), and Prune dwarf virus (PDV) were detected and infection rates were 68.4, 16.3, 9.2, and 7.1%, respectively. Infection of LChV-2 was common in all counties except Ludian where the orchards were healthy. Of 68 infected trees, 29 were found to be infected with LChV-2 and CVA, PDV or PNRSV. LChV-2 was detected in this study by RT-PCR using a pair of novel primers, LCV2-1 (5'-TTCAATATGAGCAGTGTTCCTAAC-3') and LCV2-4 (5'-ACTCGTCTTGTGACATACCAGTC-3'), in 59 flowering cherry (87%) and 8 sweet cherry (27%) trees, respectively. The primer pair was designed according to alignment of three available LChV-2 sequences (GenBank Nos. NC_005065, AF416335, and AF333237) to amplify the partial RNA-dependent RNA polymerase gene (ORF1b) of 781 bp. The amplicons of selected samples (Anning26 and Yiliang60) were sequenced directly and sequences of 651 bp (GenBank No. HQ412772) were obtained from both samples. Pairwise comparisons and phylogenetic analysis of the sequences show that the two isolates are identical to one another and share 92 to 96% at the amino acid (aa) sequence level to those of other isolates available in the GenBank database. The sequence data confirm that these isolates are a strain of LChV-2 and genetic variation among different strains is relatively high (2). Biological and serological assays are not available for the LChV-2 detection; therefore, the LChV-2 infections of these trees were further confirmed by RT-PCR using primer pair LCV2-5 (5'-TGTTTGTGTCATGTTGTCGGAGAAG-3') and LCV2-6 (5'-TGAATACCCGAGAACAAGGACTC-3'), which amplified the helicase domain (ORF1a) of ~451 bp. The amplicons from samples Anning26 and Yiliang60 were cloned and sequenced. The 408-bp sequences (excluding primer sequences) were 92 to 98% identical at the aa sequence level to those of other isolates, confirming again their viral origin. LChV-2 (genus Ampelovirus, family Closteroviridae) (4) has been associated with little cherry disease (LChD), a widespread viral disease of sweet and sour cherries (1,3). The virus is transferred between geographic areas mainly by propagated materials. Ornamental and sweet cherries are important crops in China and LChD has the potential to cause significant economic losses. Thus, certified clean stock should be used to establish new orchards. To our knowledge, this is the first report of LChV-2 in cherries in China. References: (1) N. B. Bajet et al. Plant Dis. 92:234, 2008. (2) W. Jelkmann et al. Acta Hortic. 781:321, 2008. (3) B. Komorowska and M. Cieslinska, Plant Dis. 92:1366, 2008. (4) M. E. Rott and W. Jelkmann. Arch. Virol. 150:107, 2005.

Inhibiting mild steel corrosion from sulfate-reducing bacteria using antimicrobial-producing biofilms in Three-Mile-Island process water.

Biofilms were used to produce gramicidin S (a cyclic decapeptide) to inhibit corrosion-causing, sulfate-reducing bacteria (SRB). In laboratory studies these biofilms protected mild steel 1010 continuously from corrosion in the aggressive, cooling service water of the AmerGen Three-Mile-Island (TMI) nuclear plant, which was augmented with reference SRB. The growth of both reference SRB (Gram-positive Desulfosporosinus orientis and Gram-negative Desulfovibrio vulgaris) was shown to be inhibited by supernatants of the gramicidin-S-producing bacteria as well as by purified gramicidin S. Electrochemical impedance spectroscopy and mass loss measurements showed that the protective biofilms decreased the corrosion rate of mild steel by 2- to 10-fold when challenged with the natural SRB of the TMI process water supplemented with D. orientis or D. vulgaris. The relative corrosion inhibition efficiency was 50-90% in continuous reactors, compared to a biofilm control which did not produce the antimicrobial gramicidin S. Scanning electron microscope and reactor images also revealed that SRB attack was thwarted by protective biofilms that secrete gramicidin S. A consortium of beneficial bacteria (GGPST consortium, producing gramicidin S and other antimicrobials) also protected the mild steel.

Meniscus and synovial membrane: an electronmicroscopic study on rabbits.

Seven healthy mature rabbits were used to study both the surface morphology of the meniscus using both transmission electronmicroscopy (TEM) and scanning electronmicroscopy (SEM) and articular cartilage of the femoral condyle using SEM. Results showed that the membrane covering the meniscus was structurally the extension of synovial membrane of the knee joint capsule. Additionally, the presence of canal-like openings over the membranes surface to the meniscus was noted, which were absent over the articular cartilage surface.

Evidence that the meniscus is covered by synovial membrane.

The intra-articular menisci of 10 adult Chinese white rabbits (20 menisci total) were studied histologically. The staining methods applied included: hematoxylin and eosin (HE), Mallory, and specific Van Gieson techniques (VG). On the horizontal sections of the menisci, the synovial membrane was clearly shown to be separate and distinct. On the frontal sections of the menisci, the synovial membrane was shown to cover the superior and inferior surfaces of the menisci, particularly on the inferior surface. On the sections of the menisci, it was observed that synovial membrane of the capsule was closely associated and continuous with the synovial membrane of the menisci. On sections to which Mallory and VG staining methods were applied, the synovial membrane that covered the menisci was clearly demonstrated.