[Construction of a prediction model for predicting rebleeding in patients with obscure gastrointestinal bleeding after capsule endoscopy]

Objective: To explore the risk factors of rebleeding in patients with obscure gastrointestinal bleeding (OGIB) after capsule endoscopy (CE), and construct a model to predict rebleeding. Methods: The data of patients with OGIB who underwent CE in Zhongda Hospital Affiliated to Southeast University from July 2018 to September 2021 were retrospectively analyzed. Follow-up data were obtained via electronic medical records or telephone interviews. Univariate and multivariate Cox regression models were performed to figure out the risk factors of rebleeding in OGIB patients. Then the optimal prediction model was determined and presented as a nomogram. The model was evaluated by C statistic, calibration curve and decision curve analysis. Results: One hundred and thirty patients with OGIB were included, including 64 females and 66 males, aged (55.8±17.2) years (18-87 years), and 39 (30.0%) cases developed rebleeding during follow-up. Univariate and multivariate Cox regression model analysis showed the duration of more than 2 weeks OGIB (HR=3.70, 95%CI: 1.85-7.42, P<0.001), a history of previous gastrointestinal bleeding (HR=5.25, 95%CI: 2.00-13.81, P<0.001), positive CE findings (HR=3.72, 95%CI: 1.66-8.33, P=0.001), and the lowest hemoglobin level before CE<80 g/L (HR=2.00, 95%CI: 1.02-3.84, P=0.044) were risk factors for rebleeding, while specific treatment (HR=0.25, 95%CI: 0.11-0.54, P<0.001) was a protective factor. The corresponding scores of the above five predictive factors were: OGIB duration>2 weeks: 79 points; Previous history of gastrointestinal bleeding: 100 points; The result of CE was positive: 79 points; Specific treatment:-85 points; Minimum hemoglobin before CE<80 g/L: 41 points. The prediction model constructed from the above five variables had good discriminative capability (concordance index=0.798, 95%CI: 0.732-0.865). The calibration curves showed high consistency between nomogram-predicted probabilities and actual observations. The decision curves showed that when the threshold probability was above 0.04, the use of the nomogram to predict rebleeding provided a greater net benefit than the assumption of "all patients rebleeding or no patients rebleeding". Conclusion: The prediction model established in this study has a good ability to predic rebleeding in patients with OGIB after CE examination.

[Safety and efficacy analysis of the removal of refractory esophageal self-expandable metal stents by stent-in-stent technique]

To evaluate the safety and efficacy of esophageal stent-in-stent (SIS) in patients with refractory esophageal self-expandable metal stents (SEMS). Case series study. Retrospective analysis was made on the patients with refractory esophageal SEMS treated with SIS technology in Zhongda Hospital Affiliated to Southeast University from June 2015 to June 2021. The success rate of stent removal and the incidence of adverse events were analyzed. A total of 12 patients were included, including 7 males and 5 females, aged 50-73 (62.7±8.5) years. The clinical success rate of the internal stents was 12/12, with the median retention time of [M(Q1, Q3), 64.5 (52.0, 90.8)] days. The postoperative displacement rate and severe stenosis incidence were 1/12 and 3/12, respectively. The esophageal stents were successfully removed in one endoscopic session in all patients. A small amount of mucous membrane extravasation occurred in all patients after SIS, and no patients died after 90 days of follow-up.

A new method for molecular sex identification in the emu (Dromaius novaehollandiae)

1. Sex chromosomes of emus are largely homomorphic. Therefore, the standard methodology for molecular sexing is based on screening intron length variations in sex-linked genes is not applicable. However, emu sexing requires costly and time-consuming PCR-RFLP or multiplex PCR methods.2. This experiment used a directed PCR amplification and capillary electrophoresis sexing protocol. Two distinct peaks were observed in females (ZW), while only one peak was observed in males (ZZ).3. This sexing technique proved to be rapid, non-invasive, and highly sensitive and may be useful for verifying the sex ratio and breeding management of emus.

[Application of limiting antigen avidity enzyme immunoassay for estimating HIV-1 incidence in men who have sex with men]

Objective: To estimate the incidence of HIV-1 infection in men who have sex with men (MSM) in key areas of China through HIV-1 limiting antigen avidity enzyme immunoassay (LAg-Avidity EIA), analyze the deviation from the actual results and identify influencing factors, and provided reference for improving the accuracy of estimation results. Methods: Based on the principle of the cohort randomized study design, 20 cities were selected in China based on population size and the number of HIV-positive MSM. The sample size was estimated to be 700 according to the HIV-1 infection rate in MSM. MSM mobile phone app. was used to establish a detection appointment and questionnaire system, and the baseline cross-sectional survey was conducted from April to November 2019. LAg-Avidity EIA was used to identify the recent infected samples. The incidence of HIV-1 infection was calculated and then adjusted based on the estimation formula designed by WHO. The influencing factors were identified by analyzing the sample collection and detection processes. Results: Among the 10 650 blood samples from the participants, 799 were HIV-positive in initial screening, in which 198 samples (24.78%) missed during confirmation test. Only 621 samples were received by the laboratory. After excluding misreported samples, 520 samples were qualified for testing. A total of 155 samples were eventually determined as recent infection through LAg-Avidity EIA; Based on the estimation formula , the incidence of HIV-1 infection in MSM in 20 cities was 4.06% (95%CI:3.27%-4.85%), it increased to 5.53% (95%CI: 4.45%-6.60%)after the adjusting for sample missing rate. When the sample missing rate and misreporting rate were both adjusted, the incidence of HIV-1 infection in the MSM increased to 5.66% (95%CI:4.67%-6.65%). The actual incidence of HIV-1 infection in MSM in the 20 cities might be between 4.06% and 5.66%. Conclusions: Sample missing and misreporting might cause the deviation of the estimation of HIV-1 infection incidence. It is important to ensure the sample source and the quality of sample collection and detection to reduce the deviation in the estimation of HIV-1 infection incidence.

[Difference analysis of somatic mutations between deficient mismatch repair and proficient mismatch repair gene related with colorectal cancer]

Objective: To analyze the difference of somatic mutation of DNA mismatch repair (MMR) protein deletion (dMMR) /integrity (pMMR) in colorectal cancer (CRC). Methods: A total of 93 cases of paraffin pathological tissue derived from CRC patients underwent surgical treatment and postoperative routine immunohistochemical diagnosed as dMMR in the Second Affiliated Hospital of Zhejiang University Medical College from January 2015 to January 2017 were collected and conducted the second-generation sequencing test. The expressions of 4 MMR proteins (MLH1, MSH2, MSH6 and PMS2) in CRC tissue were detected by immunohistochemistry method, and the immunohistochemistry results were re-interpreted according to the American Association of Pathologists (CAP) standard. Second-generation sequencing technology was used to detect somatic mutations of 41 genes in 93 cases of paraffin pathological CRC tissue, and Fisher's exact test was used to analyze the gene mutation differences between groups. Results: After re-evaluation according to CAP standard, 31 cases were divided into pMMR group and 62 cases in dMMR group among the 93 CRC patients. The medium number of gene mutations in the dMMR group was 9.5, higher than 3.0 of the pMMR group (P<0.001). Somatic mutation differences were found in 17 genes between the dMMR and pMMR groups, including breast cancer susceptibility genes 1 (BRCA1), BRCA2, MLH1, PDGFRA, PIK3CA, APC, ATM, KIT, MET, PMS2, MSH6, POLE, MSH2, PTCH1, epidermal growth factor receptors (EGFR), TP53 and ERBB2 genes. The pathogenic somatic mutation rates of BRAF, MLH1, MSH2 and MSH6 in the dMMR group were higher than those in the pMMR group [21.0% (13/62) vs 9.7% (3/31), 9.7% (6/62) vs 0 (0/31), 21.0% (13/62) vs 0 (0/31), 22.6% (14/62) vs 0 (0/31), P<0.05]. The mutation rate differences of BLM N515fs, BRAF V600E, PTCH1 R1308fs and KRAS G13D sites were statistically different between the dMMR group and the pMMR group [22.6% (14/62) vs 0 (0/31), 19.4% (12/62) vs 3.2% (1/31), 11.3% (7/62) vs 0 (0/31), 16.1% (10/62) vs 3.2% (1/31), P<0.05]. The mutation rates of 3 uncommon sites including BLM N515fs, MSH6 F1088fs and PTCH1 R1308fs were 28.2% (11/39), 15.4% (6/39) and 15.4% (6/39) in patients with dMMR who were missing MLH1 and PMS2 together, statistically different from all of 0 (0/31) in pMMR patients (P<0.05). Conclusions: CRC Patients with dMMR have more related gene somatic mutations. The BRAF V600E mutation is closely related to dMMR. KRAS G13D, BLM N515fs and PTCH1 R1308fs mutation sites are also associated with the expression of MMR proteins.

[Meta-analysis on association between TNF-α and CCR5Δ32 gene polymorphisms and influenza A(H1N1)pdm09]

Objective: To investigate the associations between TNF-α and CCR5Δ32 gene polymorphisms and influenza A(H1N1)pdm09. Methods: Studies in PubMed, Cochrane Library, OVID, EBSCO, Web of Science published before February 7, 2019 were retrieved comprehensively. Observational studies related to TNF-alpha and CCR5 gene polymorphisms and influenza A(H1N1) pdm09 were collected. A strict quality evaluation was carried out according to NOS scale. Meta-analysis was performed using software Revman 5.0 and Stata 11.0. Results: After screening, a total of 8 studies were included in this Meta-analysis. The results showed that TNF-α gene polymorphism rs361525 might be associated with the risk of influenza A(H1N1)pdm09 virus infection (A vs. G: OR=2.25, 95%CI: 1.09-4.65, P=0.03; AA vs. GG: OR=4.34, 95%CI: 1.65-11.41, P=0.003; AA vs. AG+GG: OR=4.38, 95%CI: 1.67-11.48, P=0.003), similar trend also found in rs1800750 (AA+AG vs. GG: OR=2.42, 95%CI: 1.24-4.71, P=0.01). The results of subgroup analysis indicated that A allele and AA+AG genotypes of rs361525 were risk factors for influenza A(H1N1) pdm09 virus infection in Caucasians. AA genotype was a risk factor for influenza A(H1N1) pdm09 virus infection in Mexican (P<0.05). There was no significant difference in the genetic polymorphism of CCR5 and the severity of influenza A (H1N1) pdm09 virus indection (P>0.05). Conclusion: People with allele A or genotype AA at rs361525, genotype AA+AG at rs1800750 of TNF-α gene might be more susceptible to influenza A(H1N1) pdm09.

[Effects of chronic intermittent hypoxia on blood pressure and vascular remodeling]

Objective: To investigate blood pressure and vascular remodeling of OSAS by establishing the chronic-intermittent hypoxia model in rat. Methods: Experiments were performed on 35 adult male Sprague-Dawley rats. Animals were randomly divided into four groups: unhandled control group (with 5 rats in it), CIH group at 9/6/3 weeks (with 10 ratsin each group). Rats in CIH group went through 8-hour intermittent hypoxia everyday, and those in control group were raising normally. After 9-week experiment, blood pressure was measured. The changes of the following indexes were observed: pathological changes of aorta and the middle aorta thickness (HE staining), the collagen of aorta wall (Masson staining). The experimental data were analyzed by SPSS 24.0 statistical software. The variance was analyzed by one-way analysis of variance, and the irregularity was selected using the calibration t test. Results: The systolic and diastolic blood pressures of the CIH9, 6, and 3 weeks groups and the control group were: (127±13) and (79±9), (124±11) and (81±7), (101±11) and (75±9), (91±10) and (65±9) mmHg (1 mmHg=0.133 kPa). The systolic blood pressure and diastolic blood pressure of the rats in the week of CIH 9 and 6 weeks were significantly higher than the control group (F=14.64, P=0.000; F=6.81, P=0.000). There was no significant difference in the mean blood pressure between the three groups of CIH and the control group. Membrane thickness in CIH9, 6 and 3 weeks and control group were: (20±2), (19±2), (14±2), (13±3) μm. Compared with the control group, the aortic pathology and thickness of the middle layer of the CIH9 and 6 weeks group were significantly thicker (F=20.24, P=0.000), but there was no significant difference between the CIH3 week group and the control group; the collagen deposition was unchanged compared with the control group. Conclusion: Intermittent hypoxia for 6 weeks or more in rats resulted in the increasement of blood pressure, morphological changes of aorta and vascular remodeling in thickened media.

[Clinical effects of superior gluteal artery perforator island flap in repair of sacral pressure ulcer]

Objective: To explore the clinical effects of superior gluteal artery perforator island flap in repair of sacral pressure ulcer. Methods: From May 2012 to May 2017, 20 patients with sacral pressure ulcers (14 males and 6 females, aged 27 to 67 years) were admitted to our department. According to the consensus staging system of National Pressure Ulcer Advisory Panel in 2016, 6 cases were in 3 stages, 14 cases were in 4 stages, with the area of pressure ulcers ranging from 5.0 cm×4.0 cm to 10.0 cm×8.0 cm. After debridement and vacuum sealing drainage, the superior gluteal artery perforator island flaps were used to repair the pressure wounds, with the area of flaps ranging from 6 cm×5 cm to 13 cm×8 cm. The donor sites were sutured directly. The survival of flaps after operation, the healing of wounds, and the follow-up of patients were observed. Results: After surgery, flaps of 20 patients survived well without reoperation. The length of hospital stay of patients was 20 to 40 days, with an average of 25 days. Eighteen patients were followed up for 6 to 24 months, with an average of 12.2 months. The flaps were in good shape and elastic recovery. There were no complications such as seroma or hematoma in the donor sites. Both the patients and family members expressed satisfaction with the shape and texture of the flap and shape of hip. Conclusions: The superior gluteal artery perforator island flap is reliable in blood supply and easy to rotate. The flap can carry a little muscle to increase the anti-infective ability. Moreover, the donor site can be directly sutured with slight damage. Thus, it is one of the good methods for repairing sacral pressure ulcers.

[Effect of perforator flap of the proper digital artery of the ulnar or radial side of finger in the treatment of webbed scar contracture of the same finger in child]

Objective: To explore the effect of the perforator flap of the proper digital artery on the ulnar or radial side of the finger in the treatment of webbed scar contracture of the same finger in child. Methods: From January 2012 to January 2016, 26 children who were treated with dressing change after burn of finger and then had webbed scar contracture along with growth and development were hospitalized in our unit, involving a total of 50 fingers. There were 14 males and 12 females among the children aged from 2 to 14 years. After the scar was dissected and released, the wound area ranged from 1.6 cm×1.0 cm to 5.0 cm×2.6 cm. The perforator flap of the proper digital artery of the ulnar or radial side of the same finger was used to repair the wound. The flap area ranged from 1.8 cm×1.0 cm to 4.6 cm×1.8 cm. The donor sites were sutured directly. The residual wounds in donor and recipient sites were repaired by full-thickness skin graft collected from inguinal area/adjacent area or adjacent perforator flap. The postoperative development and function of the fingers were followed up and observed. The range of motion of the fingers was evaluated according to the Chinese Medical Association Hand Surgery Society's upper limb functional evaluation trial standard, the Kantor Scar Cosmesis Assessment and Rating Scale was used to score the scar of finger, and the latest data were recorded. Results: The flaps and skin grafts survived successfully after operation. The patients were followed up for 6 to 24 months. The perforator flaps of the proper digital artery on the ulnar or radial side of the finger survived well at the latest follow-up, with good color and texture and a two-point discrimination distance of 9 to 12 mm. There was no contracture of the fingers, a little pigmentation in the skin graft area, no flexion deformity of the fingers, no lateral bending of the fingers to the flap-harvesting side, and no scar contracture at the webs of the fingers. Compared with that of healthy side, the development of finger was not obviously abnormal. The range of motion of the fingers was excellent in 38 fingers and good in 12 fingers, and the scar score of the fingers was 2-3 points in 31 fingers, 4-7 points in 15 fingers, and 8-10 points in 4 fingers. Conclusions: The efficacy of perforator flap of the proper digital artery of the ulnar or radial side of finger in the treatment of the webbed scar contracture of the same finger in child is reliable, with high postoperative survival rate of the flap, better color and texture, and fewer complications, which can avoid the risk of re-contracture of the finger in a short period after operation, and does not affect the growth and development of the finger.

Interactions among lncRNAs, miRNAs and mRNA in colorectal cancer

Long non-coding RNAs (lncRNAs) are longer than 200 nts non-coding transcripts and have recently emerged as one of the largest and significantly diverse RNA families whereas microRNAs (miRNAs) are highly conserved short single-stranded ncRNAs (∼18-22 nucleotides). As families of small and long evolutionarily conserved ncRNAs, lncRNAs activate and repress genes via a variety of mechanisms at both transcriptional and translational levels, while miRNAs regulate protein-coding gene expression mainly through mRNA degradation or silencing, These ncRNAs have been proved to be involved in multiple biological functions, such as proliferation, differentiation, migration, angiogenesis and apoptosis. Today, while majority of studies have focused on defining the regulatory functions of lncRNAs and miRNAs, limited information have now available for the mutual regulations of lncRNAs, miRNAs and mRNA. Thus, the underlying molecular mechanisms, in particularly the interactions among lncRNAs, miRNAs and mRNA in development, growth, metastasis and therapeutic potential of cancer still remain obscure. Colorectal cancer (CRC) is known as the third most common and fourth leading cancer death worldwide. Increasing evidence showed the close correlations among aberrant expressions of lncRNAs, miRNAs and the occurrence, development of CRC. This review summarize the potential links among these RNAs in following three areas: 1, The biogenesis and roles of miRNAs in CRC; 2, The biogenesis and functions of lncRNAs in CRC; 3, The interactions among lncRNAs, miRNAs and mRNA in tumorigensis, growth, progression, EMT formation, chemoradiotherapy resistance, and therapeutic potential in CRC. We believe that identifying diverging lncRNAs, miRNAs and relevant genes, their interactions and complex molecular regulatory networks will provide important clues for understanding the mechanism and developing novel diagnostic and therapeutic strategies for CRC. Further efforts are warranted to bring the promise of regulating their activities into clinical utilities.

[Clinical effects of heel lateral flap in repair of skin and soft tissue defects at posterior heel region]

Objective: To explore the clinical effects of heel lateral flap in repair of skin and soft tissue defects at posterior heel region. Methods: From September 2007 to April 2016, 24 patients (17 males and 7 females, aged 16-70 years) with skin and soft tissue defects at posterior heel region were admitted to our department. The size of skin and soft tissue defects after debridement ranged from 3.0 cm×2.0 cm to 5.0 cm×4.0 cm. The defects were repaired with heel lateral flaps, with size ranging from 3.5 cm×2.5 cm to 6.0 cm×5.0 cm. The flaps were transferred to the donor sites through the loose subcutaneous tunnel. The donor site was repaired by full-thickness skin graft collected from inguinal region. The survival of flaps and the follow-up of patients were observed. Results: All flaps of 24 patients survived successfully. The recipient sites and donor sites were all healed. The patients all had follow-up of 6 to 24 months. At the last follow-up, the flaps were in good shape, with nearly normal color and soft texture. There were 6 cases of grade S3 sensation and 16 cases of grade S3(+) sensation. The distance of two-point discrimination of flaps ranged from 6 to 11 mm. The lateral foot skin grafts healed well, and the skin of the lateral foot was numb in the range of 4.0 cm×2.0 cm to 9.0 cm×3.0 cm. Conclusions: Heel lateral flap can not only repair the skin and soft tissue defects in the posterior region, but also reconstruct the sensory function of the posterior region. It is an ideal method to repair the skin and soft tissue defects in the posterior region.

[Effects of free mini-flap on tibial side of third toe on repairing skin and soft tissue defect of finger pulp at the end of finger]

Objective: To investigate the effects of free mini-flap on tibial side of third toe on repairing skin and soft tissue defect of finger pulp at the end of finger. Methods: From August 2013 to May 2017, 18 patients with skin and soft tissue defect of finger pulp at the end of finger were admitted to our unit, with 12 men and 6 women aged 16 to 54 years. As the skin and soft tissue defect sites, there were 3 cases of thumb, 8 cases of index finger, 4 cases of middle finger, and 3 cases of ring finger. The area of defects ranged from 2.0 cm×1.4 cm to 3.5 cm×2.4 cm. Free mini-flaps on tibial side of third toes were designed according to area and shape of defects, and the length and width of flaps were 0.1 to 0.2 cm longer than the length and width of the defects, respectively. The area of flaps ranged from 2.1 cm×1.5 cm to 3.7 cm×2.6 cm. The end-to-end anastomosis of subcutaneous veins of flaps and superficial veins of the finger-palm side or superficial dorsal digital vein, the end-to-end tension-free anastomosis of the base metatarsal arteries on tibial side of third toe and proper digital arteries of recipient finger were performed. Besides, anastomosis of base metatarsal nerve on tibial side of third toe and proper digital nerve of recipient finger was performed. The donor sites on feet were sutured directly or repaired with full-thickness skin grafts on medial upper leg of the same side. The survival of flaps after operation and the follow-up of patients were observed. Results: All flaps survived well, with good blood supply. Among the 18 patients, 2 patients lost to follow-up, and 16 patients were followed up for 4 to 36 months. The shape and texture of flaps were good. After reconstruction, finger pulps at the end of finger were plump, with fingerprint. Function of the finger restored well, and the two-point discriminatory distances of flaps were 5 to 10 mm. The donor sites on feet of 14 patients healed after the operation, the other 2 patients had necrosis on edge and central area of skin grafts, and the necrotic area healed after dressing change. The skin graft areas on feet were wear-resistant, with slight damage to donor sites and did not influence shoes wearing and walking. Besides, patients did not feel uncomfortable. Conclusions: Skin and soft tissue defects of finger pulp at the end of finger repaired by free mini-flaps on tibial side of third toe are with good shape and slight damage to donor sites, and the operation is simple. It is worthy of popularization and application in clinic.

Facilitating the measurement of circulatory hydrogen sulfide with fluorescence probe-coated microplates

OBJECTIVE

The hydrogen sulfide (H₂S) role in pathogenesis of various diseases were wildly addressed in recent decade. The circulatory (plasma or serum) and biological fluid H₂S measurement is still an enormous issues due to the technical limitation. This paper aimed to develop a novel measurement method based on fluorescence probe.

METHODS

Firstly, 20 μL ethanol was used to dissolve 100 pmol fluorescence probe, then added in a 96-well plate. An equal volume of ethanol was also added to the blank well of the plate. The plate was placed in a dark room for about 1 h until the fluorescence probe was evenly coated in the 96-well microplate and dried. The plate was frozen at -20 °C for later use. Secondly, the plasma or serum sample was added with saturated ammonium sulfate buffer (pH 7.8) and then centrifuged to remove the proteins. The equal volume supernatant liquid was added to the probe-coated well and the probe-uncoated well. The plate was incubated in a dark environment at 37 °C for 2 h. Finally, after incubation, the fluorescence density was acquired at Λ_Ex/Λ_Em 340/445 nm in a microplate reader. The differences of the fluorescence density values between the probe-coated well and probe-uncoated well were counted and H₂S concentration of plasma/serum was calculated by standard curve with NaHS.

RESULTS

The method had high sensitivity (from 0.3 to 100 μmol/L) and specificity for measuring H₂S as compared with other biologically relevant reactive sulfur species and sulfur-containing amino acid. Serum H₂S concentrations were assayed in 188 health volunteers using this method [(12.1±3.5) μmol/L, 95%CI: 4.6-19.8 μmol/L], and the frequency distribution showed a normal tendency(one-sample Kolmogorov-Smirnov test, P>0.1). The serum H₂S concentrations in 30 hypertension patients were decreased compared with 22 age- and gender-matched health individuals (paired-samples t test, t=9.937, P<0.001). There were no differences of H₂S concentration in serum [(19.66±2.32) μmol/L] or plasma [(18.67±2.07) μmol/L], between the samples acquired from artery [(19.34±0.51) μmol/L] or vein [(18.99±0.50) μmol/L] of male Wistar rats (repeated measurement of ANOVA, P=0.38). One week frozen samples did not affect the detection. The values of the repeated measurement did not differ (two-way ANOVA, P>0.05).

CONCLUSION

The present method is easily performed with high sensitivity, specificity and repeatability for circulatory H₂S. It is also quick and may apply for large samples.

Genetic diversity of Jiangsu native chicken breeds assessed with the mitochondrial DNA D-loop region

1. The objective of this study was to determine the origin and evolution of chickens from 5 native breeds that are traditionally raised in Jiangsu Province. 2. To address this question, the complete mitochondrial DNA D-loop sequence of 149 chickens from 5 native breeds of Jiangsu Province was analysed. 3. Sequence read lengths of the native breeds were 1231 to 1232 bp, with a single-base deletion from the 859 bp site in the 1231 bp haplotype. A total of 33 variable sites that defined 19 haplotypes were identified. The average haplotype diversity and nucleotide diversity were 0.862 ± 0.017 and 0.00591 ± 0.00135. 4. Phylogenetic analysis showed that genetic structure of the mtDNA haplotypes of Jiangsu chickens are distributed across 5 clades (haplogroups): Clades A, B, C, D, and E. However, most of the individuals characterised in this study belonged to clades A and B. 5. The results of this study indicate that Jiangsu chicken populations have relatively low nucleotide and haplotype diversity and likely share 5 common maternal lineages.

[Clinical significance of σ1 receptor over-expression in cervical cancer and the effect of its synthetic ligands on the growth of cervical cancer cells]

Objective: To explore the role of σ1 receptor (σ1R) in the clinical prognosis of cervical cancer,and provide a theoretical basis for σ1R targeted molecular therapy through observing the inhibition of synthetic σ1R-specific ligand compounds on the growth of cervical cancer cells. Methods: (1) Immunohistochemical or immunocytochemistry staining were respectively used to detect the expression and localization of σ1R protein. (2) The Cancer Genome Atlas (TCGA) data set was used to validate our results. (3) Two series of 4 novel σ1R ligand compounds were synthesized by altering the N-terminal substituents on the piperidine ring of the prezamicol analogue, named as 14a, 14e, 15c and 15f. Methyl thiazolyl-tetrazolium (MTT) assay was detect the anti-proliferative effect of the four compounds on HeLa and SiHa cells. Compound 14a with potent inhibitory activity and the highest specificity of σ1R was selected for further experiments. Scratch test was observed the migration effect of compound 14a on HeLa and SiHa cells. Flow cytometry was determined cell cycles and apoptosis. Results: (1) Immunostaining of σ1R protein was located in the cytoplasm and nucleus of cervical epithelium. The expression of cervical squamous cell carcinoma (SCC) was significantly higher than those of high-grade squamous intraepithelial lesion (HSIL) or normal cervical tissues. There was no significant difference in the expression of σ1R between HSIL and normal cervical tissues. σ1R expression in cervical adenocarcinoma (AC) was higher than that in SCC (P=0.020). The nuclear expression rate of σ1R in AC (10/18) was higher than that of SCC (27.1%, 19/70; P=0.024). The median overall survival (MOS) of σ1R-positive SCC patients was lower than that of σ1R-negative patients [(45.8±3.1) vs (51.7±2.9) months, P=0.045]. MOS of the patients with σ1R nuclear positive SCC was lower than that of non-nuclear staining [(38.9±3.8) vs (48.7±2.1) months, P=0.022]. MOS of the patients with σ1R nuclear positive AC was lower than that of non-nuclear staining [(35.0±6.3) vs (44.2±4.2) months, P=0.034]. (2) Analysis of TCGA data showed that σ1R expression of in SCC was correlated with age (P=0.005). σ1R expression in AC was significantly associated with advanced stage, lymphnode metastasis and vascular invasion (all P<0.05). MOS of AC patients with σ1R overexpression was significantly lower than that of the patients with low expression (P=0.034). There was no significant difference in the MOS of different expression of σ1R mRNA in SCC patients(P=0.930). (3) MTT assay showed that these four compounds could suppressed the growth of HeLa and SiHa cells in time- and dose-dependent manner. The growth inhibition rates of HeLa and SiHa cells at 48 hours treated by combination of different concentrations of nedaplatin (NDP) with compound 14a (6 μmol/L) were significantly higher than those treated by NDP alone. Compound 14a (30 μmol/L) significantly inhibited the migration (both P<0.01) and induced the apoptosis of HeLa or SiHa cells (both P<0.01). Conclusions: σ1R is over-expressed in cervical cancer and HSIL. σ1R nuclear expression is an important marker of AC. σ1R over-expression, especially σ1R nuclear expression is associated with the poor prognosis of cervical cancer. Our study is mostly consistent with cervical cancer data of TCGA. These results suggest that the novel synthetic prezamicol analogues 14a for σ1R could inhibit the growth of cervical cancer cells and cell migration through inducing apoptosis and arresting cell cycle in G(0)/G(1) period, enhance NDP-induced cytotoxicity.

Mesenchymal stem cellular adhesion and cytotoxicity study of random biopolyester scaffolds for tissue engineering

Mesenchymal stem cells (MSCs) were isolated from the bone marrow of rabbits and inoculated respectively on 3D scaffolds of poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) (PHBV), poly(butylenes succinate) (PBS) and different blends (100/0, 80/20, 50/50, 20/80, 0/100) (Wt%) in vitro. It was found that the (50/50) blends possessed the best performance on adhesion and cytotoxicity of MSCs. The scanning electronic microscopy (SEM) results showed that the (50/50) blends had the appropriate roughness for MSCs to attach and grow, which may be used as a suitable biomaterial to create small caliber vascular grafts.

Global conformational changes upon receptor stimulation in photoactive yellow protein

Biological signal transduction starts with the activation of a receptor protein. Two central questions in signaling are the mechanism of activation by a stimulus and the nature and extent of the protein conformational changes involved. We report extensive evidence for the occurrence of large structural changes upon the light activation of photoactive yellow protein (PYP), a eubacterial photosensor. Absorption of a blue photon by the p-coumaric acid (pCA) chromophore in pG, the initial state of PYP, results in the formation of pB, a putative signaling state. In the presence of an adequate hydration shell, large structural changes in the protein backbone, involving both solvent accessible and core regions, were detected using Fourier transform infrared (FTIR) difference spectroscopy. A significant part (23%) of the amide groups which are buried in pG become exposed to the solvent in pB, as measured through light-induced H/D exchange, using both electrospray ionization mass spectrometry and FTIR spectroscopy. Exposure of previously buried hydrophobic sites would lead to an increase in heat capacity during pB formation and a decrease in heat capacity during pB decay. Thermodynamic studies indeed show that the heat capacity change of pB activation is -2.35 +/- 0.08 kJ/(mol/K), independent of pH from pH 2.4-7.5. A model for photoactivation of PYP is proposed, which provides a framework for a deeper understanding of receptor activation in general.

Hydrogen exchange/electrospray ionization mass spectrometry studies of substrate and inhibitor binding and conformational changes of Escherichia coli dihydrodipicolinate reductase

Escherichia coli dihydrodipicolinate reductase is one of seven enzymes in the succinylase pathway of bacterial L-lysine biosynthesis. The binding of NADH, a substrate, and 2,6-pyridinedicarboxylate, an inhibitor, to the recombinant, overexpressed enzyme has been analyzed using hydrogen/deuterium exchange and electrospray ionization/mass spectrometry. NADH binding reduces the extent of deuterium exchange, as does the subsequent binding of 2,6-pyridinedicarboxylate. Pepsin digestion of the deuterated enzyme and enzyme-inhibitor complex coupled with liquid chromatography/mass spectrometry has allowed the identification of four peptides whose deuterium exchange slows considerably upon the binding of the substrate or inhibitor. Two of these peptides represent regions known or thought to bind NADH and 2,6-pyridinedicarboxylate. Two additional peptides are located at the interdomain hinge region and are proposed to be exchangeable in the "open", catalytically inactive, conformation but are nonexchangeable in the "closed", catalytically active conformation formed after NADH and 2,6-pyridinedicarboxylate binding and domain closure. These studies provide a clear example of a catalytically essential domain movement in this enzyme.

Rearrangements of doubly charged acylium ions from lysyl and ornithyl peptides

The study of large-scale rearrangements of [b']2+ ions produced by electrospray ionization of Substance P (Tang et al., Anal. Chem. Vol. 65, p. 2824 (1993)) has been extended to 18 other peptides containing either a lysine or ornithine residue remote from the C-terminus. Evidence for wholesale transfer of one or more residues, from the C-terminus of the [b']2+ precursor to the omega-amino group of the Lys (or Orn) residue, was observed for 12 of the 18 peptides studied. Unfortunately, no rigorous predictive rules, relating features of the peptide sequence to the propensity to undergo such rearrangements, could be discerned although a significant correlation with presence of a proline residue close to the lysine or ornithine on the C-terminal side was apparent. The resulting mass-shifts can complicate derivation of peptide sequences from fragment-ion spectra of [M + 2H]2+ peptide ions, for example, since the cyclized [b']2+ ions responsible for the rearrangements are readily formed as intermediate species in the fragmentation mechanisms.

Investigation of protein-protein noncovalent interactions in soybean agglutinin by electrospray ionization time-of-flight mass spectrometry

Noncovalent interactions in soybean agglutinin (SBA) were studied on an electrospray ionization (ESI) time-of-flight mass spectrometer constructed recently at the University of Manitoba. The high m/z range and high sensitivity of the instrument together with mild ESI interface conditions turned out to be ideal for detecting this noncovalently bonded tetrameric protein (MW approximately 116,000 Da) in low charge states (z = 23 to 27). By altering the acetonitrile content of the SBA solutions it was shown that the observed SBA tetramers are due to structurally specific noncovalent associations in solution. Octamers and dodecamers (MW approximately 350,000 Da) were also detected. Information on the quaternary structure of the tetramers was obtained by analyzing the fragment-ion spectrum resulting from the collision-induced dissociation of the tetramer ions.

Fragmentation reactions of multiply-protonated peptides and implications for sequencing by tandem mass spectrometry with low-energy collision-induced dissociation

The low-energy collision-induced dissociation reactions of a series of multiply-protonated peptides have been investigated by tandem mass spectrometry. It is known that doubly-protonated tryptic peptides undergo facile fragmentation yielding redundant sequence information. The present work has shown that this fortunate circumstance seems likely to be the exception rather than the rule. The presence of additional basic residues, at positions other than the C-terminus, complicates the spectra. The most important such complication discovered in the present work involves wholesale transfer of one or two residues from the C-terminal end of a doubly-charged b fragment to the side chain of a lysine residue located near the N-terminus, resulting in mass shifts of the products of subsequent second-stage fragmentations. Other examples of the participation of the flexible lysine side chain are suggested but could not be confirmed to the same extent. The role of Coulombic repulsion in facilitating fragmentation has been explored via investigations of triply- and quadruply-protonated basic peptides bearing one charge for every three or four amino acid residues. Such species yielded almost no sequence information under low-energy collision conditions, due to the localization of the ionizing protons on highly basic sites rather than on the peptide backbone. It is proposed that collisionally activated mobilization of protons from the basic sites, where they are originally located upon formation, to the backbone is a necessary condition for structurally useful fragmentation to occur. It was not possible, on the basis of the present work, to deduce mechanistic generalizations and predictive schemes which would permit structural interpretations of such fragment spectra for unknown peptides.

Preparation and performance of cross-linked agar encapsulated activated charcoal (CAAC-III)

A technique is described to encapsulate activated charcoal for hemoperfusion to be used in an artificial liver support. Spherical activated charcoal was coated with agar and shaped in organic solvent, as well as cross-linked by epichlorohydrin (40-50 degrees C). The product withstood autoclaving at 121 degrees C for 0.5 hours, and had a good adsorption ability for compounds with molecular weight ranging from 113-5200. The adsorption kinetic showed pore diffusion limitation to compounds of small molecular weight, and film diffusion limitation to compounds of large molecular weight. Microparticles of charcoal release were greatly reduced, and within the permissible range according to the requirements in the U.S. Pharmacopeia (1985).

Immunochemical and immunocytochemical identification of a myosin heavy chain polypeptide in Nicotiana pollen tubes

A myosin heavy chain polypeptide has been identified and localized in Nicotiana pollen tubes using monoclonal anti-myosin antibodies. The epitopes of these antibodies were found to reside on the myosin heavy chain head and rod portion and were, therefore, designated anti-S-1 (myosin S-1) and anti-LMM (light meromyosin). On Western blots of the total soluble pollen tube proteins, both anti-S-1 and anti-LMM label a polypeptide of approximately 175,000 Mr. Immunofluorescence microscopy shows that both antibodies yield numerous fluorescent spots throughout the whole length of the tube, often with an enrichment in the tube tip. These fluorescent spots are thought to represent vesicles and/or organelles in the pollen tubes. In addition to this common pattern, anti-S-1 stains both the generative cell and the vegetative nuclear envelope. The different staining patterns of the nucleus between anti-S-1 and anti-LMM may be caused by some organization and/or anchorage state of the myosin molecules on the nuclear surface that differs from those on the vesicles and/or organelles.

Fluorescence microscopic localization of actin in pollen tubes: comparison of actin antibody and phalloidin staining

A comparison of actin localization in pollen tubes of Nicotiana has been made using a monoclonal actin antibody and rhodamine-phalloidin (RP). The monoclonal antiactin, based on Western blotting of pollen tube extract, labels a polypeptide at 45 kD that comigrates with muscle actin. A 51-kD unknown protein and three bands less than 45 kD, presumed to be proteolytic fragments of actin, are also observed. Structural observations using this antibody reveal a network of axially oriented strands of microfilaments (MFs). The MFs are distributed throughout the length of the pollen tube except at the very tip, where diffuse staining is usually observed. A similar pattern of MFs is evident after RP staining. When pollen tubes are treated with cytochalasins (CB or CD) cytoplasmic streaming is inhibited, as is tube elongation. Microscopic analysis reveals that the microfilament (MF) pattern is markedly altered; however, the antibody and RP produce different staining patterns. The antibody reveals many MF strands that distribute throughout the tube length and extend into the very tip. In contrast, RP shows mostly a diffuse staining pattern with only a few short clumps of filamentous material. Immunogold labelling of sections of pollen tubes prepared by rapid-freeze fixation and freeze substitution reveals that actin MF bundles are indeed present after cytochalasin treatment. Our results thus question reports in the literature, based on phalloidin staining, asserting that cytochalasin fragments or destroys actin MFs.

Studies of adsorbents for hemoperfusion in artificial liver support. I. Preparation and in vitro studies of cross-linked agarose beads entrapped activated charcoal (CAAC)

A new method for the preparation of the cross-linked agarose beads entrapped activated charcoal (CAAC) is reported. Since the agarose-encapsulated adsorbents reported elsewhere cannot stand high temperature for sterilization, the CAAC has the advantage of thermal stability to withstand autoclave at 121 degrees C. for 1/2 hour without breaking up or melting. A further advantage of CAAC is that the adsorbent has a much better consistency with good mechanical strength and elasticity, so that it can be formed into beads of a diameter less than 1 mm. This will not only give a better adsorption capacity than larger beads, but can also assure a better blood flow than soft beads which usually interfere in hemoperfusion due to compacting and sludging. Preliminary investigations indicate that the CAAC is relatively hemocompatible.