Spatiotemporal Controlled Formation of Synthetic Nanoreactors in Single Living Cells

Cellular compartments provide confined environments for spatiotemporal control of biological processes and enzymatic reactions. To mimic such compartmentalization of eukaryotic cells, we report an efficient and general platform to precisely control the formation of artificial nanoreactors in single living cells. We introduce an electroosmotic controlled strategy for the synthesis of ZIF-8 at the nanoscale liquid-liquid interface around the tip of a nanopipet, whereby the formed ZIF-8 nanoparticles are driven into a single living cell by the electroosmotic flow. The porous ZIF-8 nanoparticles, as synthetic nanoreactors, are not only able to harvest fluorescent molecules from peripheral cytoplasm but also perform the subsequent photocatalytic degradation, mimicking compartmentalized chemical reactions in eukaryotic cells. Our strategy provides a useful tool for spatiotemporal controlled synthesis of artificial nanoreactors with on-demand functions in single living cells with versatile applications in chemical biology.

Amperometric Identification of Single Exosomes and Their Dopamine Contents Secreted by Living Cells

Dopamine (DA) is an important neurotransmitter, which not only participates in the regulation of neural processes but also plays critical roles in tumor progression and immunity. However, direct identification of DA-containing exosomes, as well as quantification of DA in single vesicles, is still challenging. Here, we report a nanopipette-assisted method to detect single exosomes and their dopamine contents via amperometric measurement. The resistive-pulse current measured can simultaneously provide accurate information of vesicle translocation and DA contents in single exosomes. Accordingly, DA-containing exosomes secreted from HeLa and PC12 cells under different treatment modes successfully detected the DA encapsulation efficiency and the amount of exosome secretion that distinguish between cell types. Furthermore, a custom machine learning model was constructed to classify the exosome signals from different sources, with an accuracy of more than 99%. Our strategy offers a useful tool for investigating single exosomes and their DA contents, which facilitates the analysis of DA-containing exosomes derived from other untreated or stimulated cells and may open up a new insight to the research of DA biology.

Water-soluble bright NIR AIEgens with hybrid ROS for wash-free mitochondrial "off-on" imaging and photodynamic therapy

Several aggregation-induced emission luminogens (AIEgens) with excellent water-solubility and near-infrared emission were designed and synthesized for wash-free "off-on" mitochondrial imaging and photodynamic therapy of HeLa cells. The AIEgen TEPP exhibits both bright near-infrared emission (φ_F = 17.8%) and high hybrid ROS productivity (including OH˙ and ¹O₂).

[Multicenter real world study on the efficacy and safety of eribulin for the treatment of advanced breast cancer]

Objective: To explore the efficacy and safety of real-world eribulin in the treatment of metastatic breast cancer. Methods: From December 2019 to December 2020, patients with advanced breast cancer were selected from Beijing Chaoyang District Sanhuan Cancer Hospital, Shandong Cancer Hospital, Peking University Cancer Hospital, Baotou Cancer Hospital, Shengjing Hospital Affiliated to China Medical University, and Cancer Hospital of Chinese Academy of Medical Sciences. Kaplan-Meier method and Log rank test were used for survival analysis, and Cox regression model was used for multivariate analysis. Results: The median progression-free survival (PFS) of 77 patients was 5 months, the objective response rate (ORR) was 33.8%, and the disease control rate (DCR) was 71.4%. The ORR of patients with triple-negative breast cancer was 23.1%, and the DCR was 57.7%; the ORR of patients with Luminal breast cancer was 40.0%, and the DCR was 77.8%; the ORR of patients with HER-2 overexpression breast cancer was 33.3%, and the DCR was 83.3%. ORR of 50.0% and DCR of 66.7% for patients treated with eribulin as first to second line treatment, ORR of 29.4% and DCR of 76.5% for patients treated with third to fourth line and ORR of 28.6% and DCR of 71.4% for patients treated with five to eleven line. The ORR of patients in the eribulin monotherapy group was 40.0% and the DCR was 66.0%; the ORR of patients in the combination chemotherapy or targeted therapy group was 22.2% and the DCR was 81.5%. Patients with a history of treatment with paclitaxel, docetaxel, or albumin paclitaxel during the adjuvant phase or after recurrent metastasis had an ORR of 32.9% and a DCR of 69.9% when treated with eribulin. The treatment efficacy is an independent prognostic factor affecting patient survival (P<0.001). The main adverse reactions in the whole group of patients were Grade Ⅲ-Ⅳ neutrophil decline [29.9% (23/77)], and other adverse reactions were Grade Ⅲ-Ⅳ fatigue [5.2% (4/77)], Grade Ⅲ-Ⅳ peripheral nerve abnormality [2.6% (2/77)] and Grade Ⅲ-Ⅳ alopecia [2.6% (2/77)]. Conclusions: Eribulin still has good antitumor activity against various molecular subtypes of breast cancer and advanced breast cancer that has failed multiple lines of chemotherapy, and the adverse effects can be controlled, so it has a good clinical application value.

[Dynamic changes of vestibular autorotation test in patients with unilateral vestibular dysfunction during rehabilitation]

Objective: To explore the dynamic changes of vestibular autorotation test (VAT) before and after vestibular rehabilitation treatment in patients with unilateral vestibular hypofunction (UVH). Methods: A retrospective study was carried out,48 patients who were diagnosed with UVH and under vestibular rehabilitation in department of otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, from January 2019 to January 2021 were enrolled. Among them, there were 21 males and 27 females, with an average age of 46.9 years old, including 25 cases of Meniere's disease, 13 cases of sudden deafness with vertigo and 10 cases of vestibular neuritis. The course of disease ranged from 5 days to 10 years. Demographic characteristics, detailed case data and routine examination were collected for the patients. The horizontal gain/phase, vertical gain/phase, and asymmetry of VAT at different frequencies before and after vestibular rehabilitation were collected. The absolute value of the difference between the measured value of 2.0-5.9 Hz before and after rehabilitation and the standard value were statistically analyzed. Results: Before vestibular rehabilitation, the incidence of abnormal gain was 62.5% (30/48), the incidence of abnormal phase was 56.3% (27/48), and the incidence of asymmetry was 16.7% (8/48). After 4-6 weeks of vestibular rehabilitation, the incidence of gain abnormality was 22.9% (11/48), the incidence of phase abnormality was 31.3% (15/48), and the incidence of asymmetry was 12.5% (6/48).The horizontal gain at frequency of 2.0-3.9 Hz showed statistically significant difference compared with before vestibular rehabilitation (P<0.05), and the horizontal gain at frequency of 4.3-5.9 Hz showed that there was no significant difference (P>0.05); the horizontal phase at 5.9 Hz showed that the difference was statistically significant (P=0.043), and there was no significant difference before and after rehabilitation treatment at 2.0-5.5 Hz (P>0.05); the vertical gain at 4.3 Hz showed the difference was statistically significant (P=0.020), and the remaining frequency showed no significant difference (P>0.05); No frequency of asymmetry and vertical phase showed the difference before and after rehabilitation was statistically significant (P>0.05). Conclusion: VAT can be used to monitor the change trend of multiple frequency bands before and after vestibular rehabilitation in UVH, in order to provide reference for the formulation of personalized rehabilitation strategies.

[Efficacy of multisensory training and rehabilitation in patients with balance disorders]

Objective: To analyze the clinical efficacy of multisensory training and rehabilitation treatment in patients with balance disorders. Methods: From January to December 2020, 95 patients with balance disorders in the Vertigo Center of Department of Otorhinolaryngology, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology were enrolled. All patients were treated according to the treatment guidelines of Chinese Medical Association or expert consensus. Those with poor recovery or unsatisfactory treatment results underwent multisensory training and rehabilitation for 1 month after a comprehensive evaluation. The scores of Visual Analogue Scale (VAS), Dizziness Handicap Inventory (DHI), Berg Balance Scale (BBS), and Activities-specific Balance Confidence Scale (ABC), Somatization Symptom Self-Rating Scale (SSS), 9-item Patient Health Questionnaire (PHQ9) and the 7-item Generalized Anxiety Disorder (GAD7) were evaluated and compared before and after the treatment. Results: Totally, 95 patients were enrolled. There were 34 males and 61 females, aged (44±14) years. VAS (2.1±1.1 vs 5.9±2.5, P<0.01), DHI (15.6±7.7 vs 33.1±13.2, P<0.01), SSS (1.5±0.6 vs 2.4±0.8, P<0.01), PHQ9 (6.0±2.7 vs 8.6±4.3, P=0.01) and GAD7 (5.2±2.6 vs 9.5±2.8, P<0.01) decreased after treatment, while BBS (53.4±10.0 vs 34.8±10.7, P<0.01) and ABC (89.6±8.0 vs 55.7±21.8, P<0.01) increased. Conclusion: Multisensory training and rehabilitation therapy can effectively enhance the vertigo control rate and balance ability in patients with balance disorders, reduce the risk of falling, promote their mental and psychological state, and thus improve the quality of life.

[Comparison of percutaneous pedicle screw placement under O-arm navigation with traditional percutaneous pedicle screw placement in patients with thoracolumbar fractures without neurological symptoms]

Objective: To investigate the accuracy and clinical efficacy of percutaneous pedicle screw placement under O-arm navigation and traditional fluoroscopy in patients with thoracolumbar fractures without neurological symptoms. Methods: From July 2016 to July 2018, 72 patients with thoracolumbar fractures in Peking University International Hospital without neurological symptoms were divided into two groups, group A and group B. In group A, 36 patients underwent the surgery of percutaneous pedicle screw implantation under traditional fluoroscopy and 168 pedicle screws were inserted. In group B, 36 patients underwent the surgery of percutaneous pedicle screw implantation under O-arm guided fluoroscopy and 164 pedicle screws were inserted by the same surgeon. The general condition, operation condition, radiation dose, fluoroscopy time of single screw, screw placement time and accuracy, visual analogue score (VAS) score, Oswestry dysfunction index (ODI), kyphosis Cobb's angle, anterior edge height of 1 week and 6 months after surgery were compared. The data were compared with paired t test between the two groups. Results: There was no significant differences between the two groups in general condition, intraoperative blood loss, length of hospital stay, VAS, ODI, kyphosis Cobb's angle, and anterior edge height of the injured vertebra (all P>0.05). The operation time was (99±14) min in group A and (75±10) min in group B, the average screw setting time was (15.8±2.6) min in group A and (11.8±3.3) min in group B, the fluoroscopy time of each screw was (38.0±2.0) s in group A and (28.5±2.8) s in group B, the radiation dose of each surgery was (563±163) cGy/cm(2) in group A and (378±70) cGy/cm(2) in group B; the above-mentioned data of group A were all superior to those in group B and the differences between the two groups were all statistically significant (t=8.48, 5.73, 16.30, 6.25, all P<0.05). Rampersaud grading in group A was better than group B, and the differences between the two groups was statistically significant(χ(2)=12.2, P<0.05). Conclusion: The O-arm navigation system could not only provide high-definition navigation images and achieve high-precision navigation operations, which is more accurate than traditional pedicle screws placement, but also contribute to the reconstruction of spinal stability and reduce radiation dose, pedicle screws placement and operating time.

[Spatial-temporal distribution of human brucellosis and its correlation with the number of livestock in Ningxia Hui Autonomous Region, 2012-2018]

Objective: To analyze the spatial-temporal distribution characteristics of human brucellosis (HB) in Ningxia Hui Autonomous Region (Ningxia) from 2012 to 2018 and the correlation between HB and the number of livestock stocks, so as to provide reference for the development of preventive measures. Methods: Data on the incidence of HB was collected from the Infectious Disease Report Information Management System of Ningxia, 2012 to 2018. Data related to HB incidence in Ningxia from 2012 to 2018 was then analyzed by global spatial autocorrelation and local spatial autocorrelation analysis methods through the geographic information system (GIS). SPSS (23.0) Spearman correlation was used to analyze the correlation between the incidence of HB and the number of cattle, sheep and pigs. Results: From 2012 to 2018, the incidence of HB showed an overall increase in Ningxia, with an annual growth in 2012-2015 but declined between 2015 and 2018. Results from the global autocorrelation analysis showed that the distribution of HB in the counties and districts of Ningxia appeared non-randomly, with Moran's I value as positive in 2012, 2013 and 2016 indicating the distribution was positive in space. Through local autocorrelation analysis, results showed that "H-H" concentration area was mainly concentrated in central while the "L-L" concentration area was mainly in the northern part of Ningxia. As for the results from correlation analysis between HB and animal husbandry, it showed that the incidence of HB was positively correlated with the number of sheep in stock (r=0.692, P=0.000). Conclusions: The epidemic situation of HB expressed different degrees of aggregation. Areas with high incidence were mostly concentrated in central Ningxia, and with certain degree of correlation with the number of sheep in stock. Corresponding measures should be taken to control the different aggregation situation. Programs on quarantine and immunization for sheep should also be strengthened.

[The role of autophagy in PM2.5-induced inflammation in human nasal epithelial cells]

Objective: To explore the role of autophagy in PM2.5-induced inflammation in human nasal epithelial cells and related mechanism. Methods: Human nasal epithelial cells were exposed to different concentration of PM2.5 for different times, and the expression levels of microtubule-associated protein-1 light chain-3 Ⅱ (LC3 Ⅱ) and Beclin1 proteins were measured by Western blot. The typical autophagosome and autolysosome were observed by using transmission electron microscopy (TEM). To observe autophagic flux, mRFP-GFP-LC3 plasmid was transfected to nasal epithelial cells and the punctate staining of mRFP-GFP-LC3 were determined by confocal laser scanning microscope. The expression of inflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) in cell culture supernatant were assessed by enzyme-linked immunosorbent assay (ELISA). To assess the role of autophagy in PM2.5-mediated inflammation, autophagy related gene Atg5 and Beclin-1 were silenced by siRNA knockdown, and inflammatory cytokines were analyzed.GraphPad Prism 6.0 was used for statistical analysis. Results: PM2.5 exposure increased the expression of LC3 Ⅱ and Beclin-1 proteins in a dose- (in PM2.5 group with concentration of 0, 15, 30, 60, 120 μg/ml, the expression of LC3 Ⅱ was 0.021±0.001(x±s), 0.037±0.002, 0.058±0.005, 0.075±0.006, 0.085±0.004, respectively, F=126.8, P<0.05; the expression of Beclin-1 was 0.002±0.000, 0.003±0.000, 0.005±0.000, 0.007±0.001, 0.008±0.001, respectively, F=137.3, P<0.05) and time-dependent manner (in PM2.5 group with exposure time of 0, 3, 6, 12, 24 h, the expression of LC3Ⅱ was 0.160±0.007, 0.222±0.003, 0.251±0.015, 0.483±0.029, 0.585±0.035, respectively, F=215.3, P<0.05; the expression of Beclin-1 was 0.059±0.002, 0.080±0.002, 0.087±0.002, 0.183±0.007, 0.228±0.005, respectively, F=137.3, P<0.05) in human nasal epithelial cells. TEM analysis showed typical autophagosome and autolysosome in cells after PM2.5 exposure for 24 h. PM2.5 significantly increased the number of yellow and red dots representing autophagosomes and autolysosomes respectively, indicating autophagic flux was elevated. Moreover, PM2.5 enhanced the secretion of inflammatory cytokines such as IL-6 and TNF-α, which was dramatically prevented by Atg5-siRNA and Beclin-1-siRNA. Conclusion: Autophagy plays an important role in PM2.5-caused inflammation response in nasal epithelial cells, which can induce release of inflammatory factors such as IL-6 and TNF-α and advance the inflammatory reaction.

AND-Logic Based Fluorescent Probe for Selective Detection of Lysosomal Bisulfite in Living Cells

Sulfur dioxide (SO₂) plays significant roles in regulating cell apotosis and inflammation. However, there are complex interactions between small biomolecules in cells, and the identification of these coexisting biomarkers remains a challenge. Herein, we report an AND logic gate based fluorescent probe (NY-Lyso), operating by responding to pH differences between organelles in cell and selectively reacting with bisulfite (HSO₃^-). This approach allows the fluorescence of the probe to remain silent under neutral or alkaline conditions, notably, is activated by costimulation of lower pH and bisulfite. Furthermore, it was confirmed to be biocompatible and could be employed to monitor HSO₃^- in lysosomes of living cells. The proposed method demonstrated more practical and outstanding capabilities in targeted and real-time monitoring, providing an effective optical tool for biomarker sensing.

[Effect of PM2.5 on inflammatory factors and pathology of nasal mucosa in a rat model of allergic rhinitis]

Objective: To investigate the effect of PM2.5 exposure on nasal inflammatory cytokines and nasal mucosal pathology in a rat model of allergic rhinitis (AR). Methods: Twenty-four healthy female SD rats were randomly divided into 3 groups by random number table method, with 8 rats in each group: normal control group (NC group), ovalbumin (OVA) induced AR model (AR group), and AR model group inhaled to PM2.5 at 200 μg/m(3), 3 h/d, for 30 d (ARE group). Nasal symptoms including sneezing, nasal rubs and nasal secretion were recorded. Levels of OVA specific IgE in serum, interleukin 6 (IL-6) and tumor necrosis factor-ɑ (TNF-ɑ) in nasal irrigating solution were measured by enzyme-linked immunosorbent assay (ELISA). The histopathological changes of nasal mucosa were observed by HE staining. SPSS 17.0 software was used to analyze the data. Results: The number of sneezing, nasal rubs and the amount of nasal secretion in the ARE group were significantly higher than that in the AR group and the NC group (number of sneezing (15.38±1.68) times/15 min vs (11.63±1.13) times/15 min vs (1.75±0.71) times/15 min, number of nasal rubs (27.75±2.12) times/15 min vs (21.25±2.96) times/15 min vs (5.25±1.04) times/15 min, amount of nasal secretion (18.90±2.07) mg vs (13.83±1.81) mg vs (3.78±0.41) mg, F values was 236.089, 224.139, 183.971, respectively, all P<0.001). Statistically significant differences in OVA specific IgE, IL-6 and TNF-ɑ levels were observed in ARE group exceeded AR group and NC group (OVA specific IgE (25.42±2.51) ng/ml vs (18.07±1.07) ng/ml vs (1.47±0.26) ng/ml, IL-6 (123.30±18.86) pg/ml vs (63.49±11.29) pg/ml vs (16.87±3.29) pg/ml, TNF-ɑ (162.50±38.15) pg/ml vs (72.96±11.28) pg/ml vs (27.52±4.15) pg/ml, F values was 481.604, 138.277, 63.938, respectively, all P<0.001). HE staining showed that the nasal epithelial cells of NC group were intact and neatly arranged. Nasal mucosa epithelial cells were arranged in disorder in AR group, with tissue structure swelling. Partial shedding of nasal epithelial cells, mucosal basement membrane thickening, submucosal tissue interstitial edema, vasodilation and gland hyperplasia were found in ARE group. Conclusion: An increase inflammatory factors level such as IL-6 and TNF-ɑ aggravates pathological damage of nasal mucosa in a rat model of AR by exposure to PM2.5.

[Expression and clinical significance of Ser10 phosphorylated p27(kip1) protein in human breast carcinoma]

Objective: To explore the expression and clinicopathological significance of Ser10 phosphorylated p27(kip1)(P-p27Ser10) protein in human breast carcinoma tissue. Methods: Tissue specimens were obtained from 111 cases with breast carcinoma from January 2004 to December 2005. And the expression of P-p27Ser10 protein for each specimen was detected by immunohistochemical (EnVision) analysis. Six representative paired samples of cancerous and paired adjacent normal tissues were collected and detected by Western blot. The relationships between the expression levels of P-p27Ser10 protein and its clinicopathological characteristics in primary breast carcinoma were retrospectively analyzed.The association of P-p27Ser10 and Jab1 protein was detected by co-immunoprecipitation method. Results: A high-level expression of P-p27Ser10 was present in cancerous tissues but not in paired adjacent normal tissues. The positive expression rate of P-p27Ser10 protein was as high as 88.3% (98/111) and 7.2% (8/111) in cancerous and paired adjacent normal tissues respectively (P<0.05). P-p27Ser10 expression was correlated with tumor size, lymph node metastasis and TNM stage (all P<0.05). P-p27Ser10 expression was significantly correlated with Ki-67 (r=0.582, P<0.05), and inversely correlated with p27 (r=-0.426, P<0.05). Co-immunoprecipitation revealed that the association of P-p27Ser10 and Jab1 protein was increased in breast carcinoma. Conclusion: Over-expression of P-p27Ser10 protein might play an important role in the pathogenesis of breast carcinoma. P-p27Ser10 protein therefore represents a novel diagnostic marker and therapeutic target in patients with breast carcinoma.

[The clinical analysis of instrumentation failure after corrective surgery for thoracolumbar focal kyphosis]

OBJECTIVE

To analyze the etiology of instrumentation failure after corrective surgery for thoracolumbar focal kyphosis, and make suggestion for treatment.

METHODS

Retrospective study for 8 patients with thoracolumbar focal kyphosis who underwent surgical treatment and suffered instrumentation failure from June 2005 to December 2011 was made. The surgical procedures included pedicle subtraction osteotomy (PSO), anterior opening-posterior closing osteotomy and correction (AOPC), and posterior vertebral column resection (VCR). The reasons of instrumentation failure were analyzed and revision surgeries were performed.

RESULTS

The incidence of instrumentation failure was 6.3%. The average occurrence time was 22.5 months after surgery. Except one had failure in 3 months after surgery, all cases happened after 1 year. In this series, there were 5 cases with post-tuberculosis, 2 cases with post-traumatic kyphosis and 1 case with congenital kyphosis. For the surgical procedure, 7 cases underwent VCR and 1 case AOPC. After the instrumentation failure, all cases had back pain, and 3 of them had combined neurological symptoms. The reasons or risk factors of instrumentation failure included non-fusion of bone graft, VCR procedure, sink of the titanium mesh, insufficiency of anchor sites, and more severe kyphosis. All the 8 cases were treated with revision surgery and got good results.

CONCLUSIONS

The instrumentation failure of thoracolumbar focal kyphosis is relatively late occurred, and can develop with various reasons. Positive revision surgery is suggested for the instrumentation failure, and good results can be expected.

[Clinical analysis of 67 cases of surgical site infection after spine surgery]

OBJECTIVE

To investigate the treatment of surgical site infection(SSI) after spine surgery.

METHODS

Sixty-seven patients (aged 20-77 years with mean age of 51 years) with etiologically-confirmed surgical site infection after spine surgery in Peking University Third Hospital between July 2004 and December 2012 were retrospectively analyzed. There were 39 male and 28 female patients; 47 lumbar infections, 4 thoracic infections, 7 lower cervical infections and 8 upper cervical infections; 64 early infections and 3 delayed infections; 23 superficial infections and 44 deep infections; 47 monomicrobial infections and 20 polymicrobial infections. Ninety-six strains of bacteria were identified from the bacterial culture of 67 patients. Sixty strains were gram-positive pathogenic bacteria (62.5%), and the top three species were Staphylococcus aureus, S. epidermidis and Enterococcus faecalis. The remaining 36 strains were gram-negative pathogenic bacteria (37.5%), and the 3 species most predominant were Escherichia coli, Enterobacter cloacae, and Acinetobacter baumannii. All the patients with SSI were administered antibiotics. Debridement and irrigation-suction was performed if little symptomatic improvement was achieved in two-to-three days of antibiotics treatment, patients underwent 1-5 times of debridements (mean 1.5 times).

RESULTS

One patient was dead of MRSA septicemia, whom manifested as high fever, alalia and incision swelling when the infection occurred. The patient underwent polymicrobial of pulmonary infection and urinary tract infection during the period of hospitalization, and finally died of multiple organ failure. Sixty-six cases had wound healed, and they were followed up for 25-117 months (average 70 months), no recurrence of infection was found at last follow-up. Among the 65 cases of internal fixation, 56 cases reserved the implants, while implants were removed in other 9 cases for controlling infection.

CONCLUSION

Reasonable antibiotics and irrigation-suction are effective methods for managing surgical site infections after spine surgery and prevent removal of implants.

Use of porcine acellular dermal matrix following early dermabrasion reduces length of stay in extensive deep dermal burns

OBJECTIVE

Extensive deep partial-thickness burns still seriously challenge the surgeon's abilities. This study aimed to assess the impact of early dermabrasion combined with porcine acellular dermal matrix (ADM) in extensive deep dermal burns.

METHODS

From September 2009 to September 2013, a total of 60 adult patients sustained greater than 50% total body surface area (TBSA) burn by hot water or gas explosion were divided into three groups based on dermabrasion: group A (early dermabrasion and porcine ADM), group B (early dermabrasion and nano-silver dressings), and group C (conservative group). The wound healing time and length of hospital stay were analyzed. Scar assessment was performed at 3 and 12 months after the injury with a modified Vancouver Scar Scale linked with TBSA (mVSS-TBSA).

RESULTS

No significant difference was found in mean burn size, burn depth, age, male-to-female ratio, or incidence of inhalation injury between the patients in the three groups (p>0.05). Compared with groups B and C, the patients that received early dermabrasion combined with porcine ADM had a shorter wound healing time (p<0.01). The burn patients treated with early dermabrasion and porcine ADM coverage had a mean length of hospital stay of 28.3 days (±7.2), which was significantly shorter than that of groups B and C (p<0.05-0.01). The mVSS-TBSA of patients in group A was significantly improved in comparison with groups B and C at 3 and 12 months after the injury. There was no significant difference in the mortality rate between the three groups (p>0.05).

CONCLUSION

Early dermabrasion combined with porcine ADM coverage facilitates wound healing, reduces the length of hospital stay, and improves esthetic and functional results in extensive deep dermal burns with burn size over 50% TBSA.

Conformational adjustments of SNase R and its N-terminal fragments probed by monoclonal antibodies

Two monoclonal antibodies specific for staphylococcal nuclease R (SNase R) (McAb2C9 and McAb1B8) were prepared and used to probe protein folding during peptide elongation, by measuring antibody binding to seven N-terminal fragments (SNR141, SNR135, SNR121, SNR110, SNR102, SNR79 and SNR52) of SNase R. Comparative studies of the conformations of the N-terminal fragments have shown that all seven fragments of SNase R have a certain amount of residual structure, indicating that folding may occur during elongation of the nascent peptide chain. We show that the binding abilities of the intact enzyme and its seven fragments to the monoclonal antibodies are not simply proportional to the length of the peptide chain, suggesting that there may be continuous conformational adjustment in the nascent peptide chain as new C-terminal amino acids are added. A folding intermediate close in structure to the native state but with structural features in common with SNR121 is highly populated in 0.6 M GuHCl, and is also formed transiently during folding.

[Determination of chiral purity of synthetic amino acids by high performance liquid chromatography]

A series of synthetic beta-heterocyclic and beta-naphthyl alanine and aromatic substituted phenylalanine were separated by reversed-phase HPLC as diastereomeric derivatives obtained after derivatization with (1-fluoro-2,4-dinitrophenyl)-5-L-valinamide (FDNP-Val-NH2). The separation was performed with gradient elution. The mobile phase A was acetonitrile containing 0.1% trifluoroacetic acid and mobile phase B was 0.1% trifluoroacetic acid. According to the hydrophobicity of the side chain of the amino acids, 6 different linear gradient programs were selected and all gradients completed in 20 minutes. Good resolution was obtained for neutral amino acids. All L-L diastereomer of neutral amino acids (the first letter refers to the configuration of amino acid) were eluted faster than the D-L diastereomer with retention times less than 16 minutes. In the same gradient eluting system, the hydrophobic parameter (pi value) and the position of the substituent in benzene ring of phenylalanine also influence the retention time of diastereomers. Usually the retention time of the phenylalanine with a large pi value was longer than that with a small one. Among the three phenylalanines containing the same substituent, compounds with the substituent in 2-postion gave the shortest retention time. In the case of basic amino acids, the D-L diastereomers eluted prior to the L-L diastereomers and showed rather poor resolution. The chiral purity (ee) of the optical active amino acids (synthetic DL-amino acids after resolution by different enzymes) were calculated with the equation as follows: ee = [[A(L- or D-) - A(D- or L-)]/[A(L-) + A(D-)]] x 100% (L- or D-), A: peak area; L-, D-: amino acid diastereomer.

Production and characterization of monoclonal anti-idiotypic antibody exhibiting a catalytic activity similar to carboxypeptidase A

A new approach for producing catalytic anti-idiotypic antibody was developed. A monoclonal anti-idiotypic antibody which was induced against carboxypeptidase A (CPA) showed the catalytic activity similar to the original antigen. The activity of the catalytic antibody was investigated. Rabbits were immunized by bovine pancreas carboxypeptidase A. The antiserum was purified and used as antigen to immunize BALB/c mice to induce monoclonal anti-idiotypic antibodies. Screened for enzymatic activities, the monoclonal antibody 32C3 showed esterase activity. The hydrolysis of hippuryl-DL-phenyllactic acid by McAb 32C3 followed the enzymatic kinetics. In our experimental system, Kcat value was 0.0123 min-1 and Km was 0.04M. The acceleration rate was 1750 times compared to the rate of self-hydrolysis of the substrate. This hydrolysis reaction can be competitively inhibited by hydrocinnamic acid. This method could be effective to obtain catalytic antibodies with the characters close to natural enzymes.

A monoclonal antibody selected for probing the folding of staphylococcal nuclease and its N-terminal fragments

Monoclonal antibody McAb2C9 against Staphylococcal nuclease (SNase R) and its N-terminal fragments was produced and characterized. It was observed that the intact enzyme SNase R and its seven fragments (SNR141, SNR135, SNR121, SNR110, SNR102, SNR79 and SNR52) differed in their interactions with McAb2C9. However, the fragments with weak immunoreactivity, such as SNR141 and SNR110, increased ability reacting with McAb2C9 in their partially unfolded state. It suggests that the differences of immunoreactivity among the fragments are due to diverse extent of the exposure of the specific epitope and the conformation of the peptide fragment. The monoclonal antibody McAb2C9 could be a useful probe to investigate the mechanism of folding of SNase R and its N-terminal fragments.

A self-assembled antibody electrode for HT29 tumour cells

The present paper describes a self-assembled monoclonal-antibody immunosensor for HT29 tumour cells. This immunosensor is composed of two parts. One is a three-electrode system and the other is a layer of anti-(human colonic tumour) monoclonal antibody DF-I, which self-assembled on to the gold electrode. Two kinds of cells, HT29 tumour cells and normal fibroblast cells, were compared using the antibody electrode. The result was the same as that obtained by using immune luminescence. The HT29 cells can be captured specifically by the assembled anti-HT29 monoclonal-antibody electrode and can be measured by an electrochemical method.

Perturbation of the antigen-binding site and staphylococcal protein A-binding site of IgG before significant changes in global conformation during denaturation: an equilibrium study

Although conformational perturbation of the active sites of many enzymes has been reported to precede global molecular conformational changes [Tsou (1993) Science 262, 380-381], little effort has been made to compare the susceptibility of the ligand-binding site of proteins and the protein molecules as a whole to perturbation by denaturants. Immunoglobulin is chosen in this study to address this problem. It is found that the variable and constant regions (Fv and Fc) of a monoclonal antibody of an IgG subclass against adenylate kinase lose their abilities to bind antigen and staphylococcal Protein A after treatment with guanidinium chloride concentrations considerably lower than those required to change the global conformation of the antibody as a whole, as detected by fluorescence and second-derivative UV absorption spectroscopy. These results indicate that both ligand-binding sites of the antibody concerned are more fragile than the molecule as a whole and that the Fv and Fc regions of the antibody molecule unfold sequentially during denaturation.

Production and characterization of a monoclonal antibody against sterigmatocystin

A monoclonal antibody, McAb-ST, specific for sterigmatocystin (ST) was produced in vitro and in vivo by a hybridoma anti-ST1. Anti-ST1 was prepared by fusion of SP2/0 murine myeloma cells with spleen cells isolated from BALB/c mouse that had been immunized with a complete antigen BSA-ST (ST conjugated to bovine serum albumin). Analysis revealed that McAb-ST was of the IgG1 type, the molecular weight of McAb-ST was 168,000 daltons (53,000 for each heavy chain, 31,000 for each light chain), and the apparent affinity constant of McAb-ST with H-ST (Hemocyanin and ST conjugate) was 1.29 x 10(9) mol/L. The relative cross reactivities of McAb-ST with ST analogs were less than 2% when determined by a competitive indirect enzyme-linked immunosorbent assay (CI-ELISA). The minimal 0.5 pg of ST in 50 microliters of solution could be detected with CI-ELISA using McAb-ST, with a linear range of 0.1-10 ng/mL.

Detection of the organophosphorus nerve agent sarin by a competitive inhibition enzyme immunoassay

Two artificial antigens, NalphaNepsilon-di(O,O-diisopropyl) phosphoryl L-lysine (DIP)- bovine serum albumin (BSA) conjugate (DIP-BSA) and DIP-KLH (keyhole limpet hemocyanin), were synthesized. Antibodies against sarin (O-isopropyl methylphosphonofluoridate) were obtained after immunization of rabbits with DIP-KLH conjugate. A competitive inhibition enzyme immunoassay (CIEIA) was developed to detect the organophosphorus nerve agent sarin. The antibody solutions could be inhibited by sarin as low as 10(-6) mol/l, and the standard curve was linear over 3 orders of magnitude. The coefficients of intraassay and interassay variation of this method were 5.4-6.2% (n = 11) and 8.0-9.5% (n = 6) at a sarin concentration range of 10(-3)-10(-6) mol/l, respectively. The recovery of sarin in water samples at the concentration of 5 x 10(-5) mol/l was in the range of 96.8-102.5%. The specificity of the antiserum was assessed by comparing the inhibition induced by sarin with soman, Vx, isopropyl alcohol and isopropyl methyl phosphonic acid. The results showed that less than 5 mmol/l soman, 2 mmol/l Vx, 16 mmol/l isopropyl alcohol and 8 mmol/l isopropyl methyl phosphonic acid did not influence the determination of sarin in water samples.

Production, characterization and application of monoclonal antibodies against the organophosphorus nerve agent Vx

Two monoclonal antibodies (Vx-BB8 and Vx-EA11) to the chemical warfare agent Vx were produced and characterized. A competitive inhibition enzyme immunoassay was developed to detect Vx concentrations as low as 3.7 x 10(-7) - 3.7 x 10(-6) mol/l in biological samples. Vx-BB8 400 micrograms given intravenously immediately before 1 x LD95 Vx or 400 micrograms Vx-BB8 intraperitoneally 1.5 h-3 days before 1 x LD95 Vx could protect all the tested mice from death.

[Preliminary study on relationship between syndrome differentiation of esophageal cancer and changes of exfoliated cells of tongue coating]

Exfoliated cells of tongue coating of 63 esophageal cancer (EC) cases have been investigated by applying exfoliate cytologic examination, which showed that abnormal cornified cells were commonly seen while they were less in the patients of EC than those in the healthy group, and their difference was significant (P < 0.05), It showed an increase mainly in the number of pro-cornified cells in the patient of the Qi-Yang Deficiency group, an increase mainly in completely cornified cells in the Yin Deficiency and an increase in both pro-cornified cells and completely cornified cells in Phlegn-Dampness and blood Stasis patients. The difference among four groups was significant (P < 0.05). The changes of exfoliated cells of tongue coating provided an objective index for the early diagnosis of EC.

[Determination of the thickness of the wall of portal vein trunk in patients of schistosomiasis japonica with hepatic fibrosis and its clinical significance]

The thickness of the wall of the portal vein trunk (PVT) was determined with B-mode ultrasonography in 82 patients of schistosomiasis, with hepatic fibrosis, 35 cases of schistosomiasis without hepatic fibrosis, 30 cases of post-hepatitis cirrhosis and 32 healthy subjects. It was shown that the wall thickness of PVT increased in all the patients with schistosomiasis. The thickness in patients of schistosomiasis with hepatic fibrosis was markedly increased as compared with the other three groups (P < 0.01 in all). The magnitude of increase of the wall thickness correlated well with the severity of the pathological change of hepatic fibrosis. It was also noted that change of wall thickness of PVT was not only accompanied by change in hyaluronate and hydroxyproline estimation, but also closely correlated with the international criteria of ultrasound parameters for assessment of pathological changes of schistosomiasis (rs = 0.839, rs = 0.748). Measurement of the wall thickness of PVT is, therefore, a valuable clinical method for diagnosing schistosomiasis with hepatic fibrosis and determining the severity of its pathological change.

[Experimental study on effects of 18 kinds of Chinese herbal medicine for synthesis of thromboxane A2 and PGI2]

The effect of 18 kinds of Chinese herbal medicine for the synthesis of TXA2 and PGI2 was studied. The porcine lung microsoma was used as donor of enzymes such as cyclo-oxygenase, thromboxane A2 synthetase and prostacyclin synthetase, etc. It was found that Glehnia littoralis could inhibit the synthesis of TXA2 and increase the formation of PGI2. Rheum palmatum (300 mg group) and Erigeron breviscapus significantly inhibited the synthesis of TXA2, but no apparent effection on the synthesis of PGI2. When Codonopsis pilosulae, Astragalus membracaceus, Angelica sinensis, Ginsenosides and Baicalin, etc. markedly inhibited the formation of TXA2 and mildly affected the formation of PGI2. Some Chinese herbs for promoting blood circulation play an important role on the inhibition of TXA2 synthesis. Some tonic herbs could either inhibit the synthesis of TXA2 and increase the synthesis of PGI2 or inhibit the formation of PGI2. Therefore these tonic herbs had the characteristics of both strengthening the body resistance and eliminating pathogenic factors. In this aspect they are better than the control drug (Aspirin) and other herbs of promoting blood circulation.

[Changes in microstructure and ultrastructure between differentiation of cold and heat syndrome in chronic atrophied gastritis and exfoliative cells]

In this paper, exfoliative cells of fur in 56 cases of chronic atrophied gastritis (CAG) with Cold or Heat syndrome was observed by means of microscopy and electron microscopy. With microscopy, the authors found that keratinization of epithelial cells of fur in Cold syndrome group of CAG were markedly fewer than those in Heat syndrome group (P less than 0.01); while pre-keratinization cells were much more than those in Heat syndrome group (P less than 0.01); the constituent ratio of complete keratinization cells of fur in the two groups were markedly different. With the electron microscopy, fibrosis changes was appeared in pre-keratinization cells of Cold syndrome patients with CAG; desmosome was disappeared; metachromasia was appeared in nucleus; fibrosis change in Heat syndrome group was not obvious. Cells were still joined to one another by fingered protrusion. There were bacterias in both Cold and Heat syndrome groups. The change of exfoliative cells of fur in Cold and Heat syndromes in CAG, probably, can offer us a microcosmic sign for its early differentiation or diagnosis.

Tissue cryopreservation and rewarming study on giant cell tumor of bone

An attempt has been made of cryopreservation of tissue fragments from 6 GCTB surgical specimens. They have been kept in 10% DMSO or 15% glycerol medium and stored in liquid nitrogen for periods up to 180 days. Tumor cellular components survive the process of slow freezing and rapid thawing as cellular growth is successful in subsequent culture. Though certain reversible ultrastructural changes have been detected, no apparent distinction could be found in microscopic morphology, motility, growth behavior and LDH isozyme pattern between cultured cells of the cryopreserved fragments and those of the fresh ones. Electron microscopy shows that DMSO exceeds glycerol in protecting the ultrastructure of the cells. Slow cooling and rapid thawing is recommended because ice-crystals form in the intercellular space, which causes only light damage to the cells.