[Immunogenicity of group A+C meningococcal polysaccharide conjugate vaccine in infants: A phase Ⅲ clinical trial study]

Objective: To evaluate the immunogenicity of group A+C meningococcal polysaccharide conjugate vaccine in infants under 2 years old. Methods: From March 2017 to June 2018, 1 932 healthy infants in Biyang County, Henan Province, who were not vaccinated with meningococcal meningitis vaccine and whose axillary temperature was ≤37.0 ℃, were recruited as participants. The 3 months and 6-11 months old infants were allocated to the experiment group and the control group in a ratio of 1∶1. Infants aged 12-23 months were allocated to the 1-dose group, the 2-dose group and the control group in a ratio of 1∶1∶1, with 276 infants in each group. The infants in the experiment group were intramuscularly injected with freeze-dried group A+C meningococcal polysaccharide conjugate vaccine to be evaluated, and infants in the control group received intramuscular injection of commercially available freeze-dried group A+C meningococcal conjugate vaccine. The venous blood of infants was collected 30 days before the first dose and after the last dose of inoculation, and the antibody seroconversion of each group was determined and compared. Results: The completion rate of immunogenicity study was 95.2% (1 839/1 932). Before inoculation, there was no statistical difference in the geometric mean titer and positive rate of group A+C antibodies between the experiment group and the control group in 3 months and 6-11 months old infants (all P values >0.05). The geometric mean titers and positive rate of group A antibodies in the 1-dose group were higher than those in the control group (all P values <0.05), but there was no statistical difference between the 2-dose group and the control group (all P values >0.05) in infants aged 12-23 months. After inoculation, the differences (95%CI) in the positive conversion rate of group A+C antibodies between the experiment group and the control group were -0.12% (-6.01%-5.77%) and 0.82% (-4.23%-5.86%) in the 3 months old infants. At the age of 6-11 months, the differences were 6.75% (1.71%-11.79%) and -4.32% (-8.73%-0.08%), respectively. At the age of 12-23 months, the differences were 1.02% (-3.80%-5.83%) and -4.40% (-7.79%- -1.01%) in the 2-dose group and -7.22% (-12.90%- -1.54%) and -18.61% (-23.75%- -13.46%) in the 1-dose group, respectively. The geometric mean titers of group A+C antibodies in the 3 months old infants were 48.50 and 63.12, respectively, which had no significant difference from the control group (43.02 and 57.99, respectively) (both P values <0.05). The geometric mean titers of group A+C antibodies in the 6-11 months and 12-23 months old infants were 84.09 and 92.51 (2-dose group), which were higher than those in the corresponding control group (43.10 and 61.83, respectively) (all P values <0.001). Conclusion: Group A+C meningococcal conjugate vaccine has good immunogenicity in infants under 2 years old.

[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.

Fabrication of Metallic Superhydrophobic Surfaces with Tunable Condensate Self-Removal Capability and Excellent Anti-Frosting Performance

Laser fabrication of metallic superhydrophobic surfaces (SHSs) for anti-frosting has recently attracted considerable attention. Effective anti-frosting SHSs require the efficient removal of condensed microdroplets through self-propelled droplet jumping, which is strongly influenced by the surface morphology. However, detailed analyses of the condensate self-removal capability of laser-structured surfaces are limited, and guidelines for laser processing parameter control for fabricating rationally structured SHSs for anti-frosting have not yet been established. Herein, a series of nanostructured copper-zinc alloy SHSs are facilely constructed through ultrafast laser processing. The surface morphology can be properly tuned by adjusting the laser processing parameters. The relationship between the surface morphologies and condensate self-removal capability is investigated, and a guideline for laser processing parameterization for fabricating optimal anti-frosting SHSs is established. After 120 min of the frosting test, the optimized surface exhibits less than 70% frost coverage because the remarkably enhanced condensate self-removal capability reduces the water accumulation amount and frost propagation speed (<1 μm/s). Additionally, the material adaptability of the proposed technique is validated by extending this methodology to other metals and metal alloys. This study provides valuable and instructive insights into the design and optimization of metallic anti-frosting SHSs by ultrafast laser processing.

Development of solid state terahertz interferometer for the first plasma on HL-2M tokamak

A solid state terahertz interferometer has been developed on the recent commissioned HL-2M tokamak. It can work in a wide frequency region of 220-325 GHz, and the terahertz wave is generated from a low frequency phase locked voltage controlled oscillator with the frequency multiplying technique. A phase processor based on field programmable gate array (FPGA) technology is designed for the heterodyne interferometer, and it contributes to real-time display of electron density. To extract phase information, a novel numerical algorithm related to fast Fourier transform is written on the FPGA chip and enables one to obtain phase shift without being affected by amplitude variation induced by plasma absorption or frequency modulation from the outer electromagnetic environment. The interferometer achieves minimum measurable electron density in the order of 10¹⁶ m^-3. With the plasma diagnosis, electron density and low frequency tearing mode have been measured during the first experimental campaign.

[Application of autologous platelet-rich plasma separation in cardiac valve replacement: a random clinical trial]

Objective: To examine the blood protective effect of autologous platelet-rich plasma separation for cardiac valve replacement under cardiopulmonary bypass. Methods: Sixty patients who underwent cardiac valve replacement under cardiopulmonary bypass from August 2018 to May 2019 in Shanghai Chest Hospital, Shanghai Jiao Tong University were randomly divided into control and treatment groups(each 30 cases). There were 33 males and 27 females, aged (52.0±8.4) years (range: 35 to 65 years). Autologous platelet separation was performed in the treatment group after anaesthesia administration and was completed before systemic heparinisation. Platelet separation was not performed in the control group. The thromboelastogram, blood routine, blood coagulation, perioperative fluid infusion, allogeneic blood transfusion, postoperative pleural fluid volume and postoperative fibrinogen were recorded before the operation, and 1 hour and 24 hours post operation. The two groups' data was compared by t test, Kruskal-Wallis test, Mann-Whitney U test or χ(2) test. Repeated measurement analysis of variance was used to compare platelet and coagulation indexes at different times. Results: The perioperative red blood cell transfusion of 0, 1~2, 3~4,>4 units with 6, 11, 1, 12 cases in treatment group and 14, 8, 6, 2 cases in control group (Z=-2.516, P=0.012). The postoperative fibrinogen of 0, 1, 2 units with 19, 2, 9 cases in treat group and 26, 2, 2 cases in control group (Z=-2.190, P=0.029). There was no significant difference in the cost of blood transfusion between the two groups during admission ((1 732±1 275) yuan vs. (1 176±941) yuan; t=-1.570, P=0.125). Conclusion: The use of autologous platelet-rich plasma separation can reduce the amount of allogeneic blood transfusion during valvular surgery under cardiopulmonary bypass.

[ Ⅲ ]

Objective: The aim of this study was to evaluate the safety and immunogenicity of the first domestic ACYW135 meningococcal conjugate vaccine and a control vaccine named AC group meningococcal conjugate vaccine for 3 months (90-119 days) infants. Methods: From February 2017 to June 2018, a randomized, blinded, and similar vaccine-controlled clinical trial design was adopted at the Henan Vaccine Clinical Research Base. The subjects were 3 months old healthy infants, a total of 720, based on a 1∶1 ratio. The random allocation table for entry was randomly assigned to the experimental group and the control group. According to the 3, 4, and 5 month-old vaccination procedures, the subjects were vaccinated with test vaccine (ACYW135 group meningococcal conjugate vaccine) and control vaccine (group A group C meningococcal polysaccharide conjugate vaccine), of which 720 were given the first dose, 696 were given the second dose (test group: 346; control group: 350), and 692 were given the third dose (test group: 344; Control group: 348). Results: The overall adverse reaction rate of the test vaccine was 21.90% (230 cases), which was lower than the 32.04% (339 cases) of the control vaccine (P<0.001). The incidence of systemic adverse reactions was 19.52% (205 cases), which was lower than that of the control vaccine (27.69%) (293 cases) (P<0.001). The local adverse reaction rate was 3.04% (32 cases), which was lower than the control group (7.84%) (83 cases) (P<0.001). The graded adverse reaction test vaccine was 0.57% (6 cases), which was lower than the control group of 2.36% (25 cases) (P<0.001). The positive conversion rate of anti-bacterial serum antibodies showed that there was no significant difference between the test vaccine group A (91.42%), C (88.76%) and the control vaccine (92.92%) (87.02%) (P>0.05). Group Y and W135 was 88.17% (298 cases), 99.41% (336 cases), respectively. The GMT results showed that the test vaccine group A was 56.24, the control vaccine was 57.43 (P>0.05); the group C test vaccine (43.53) was higher than the control group (27.28) (P<0.001). The group Y and W135 are 89.22 and 140.66, respectively. Among them, the proportion of the group C GMT antibody ≥ 1∶128 for test vaccine (31.07%, 105 cases) was higher than the control vaccine (16.22%, 55 cases) (P<0.001). Conclusion: ACYW135 group meningococcal conjugate vaccine has more safety and immunogenicity after application to 3 month old infants.

LukS-PV induces apoptosis in acute myeloid leukemia cells mediated by C5a receptor

LukS‐PV is one of the two components of Panton‐Valentine leucocidin (PVL). Our previous study showed that LukS‐PV can induce apoptosis in human acute myeloid leukemia (AML) THP‐1 and HL‐60 cells. C5aR (C5a receptor) is the receptor for PVL, but whether C5aR plays a key role in LukS‐PV induced apoptosis is unclear. The aim of this study was to establish whether C5aR plays a physiological role in apoptosis of leukemia cells induced by LukS‐PV. We investigated the role of C5aR in leukemia cell apoptosis induced by LukS‐PV by pretreatment of THP‐1 and HL‐60 cells with C5aR antagonist and transfection to knockdown C5aR in THP‐1 cells or overexpress C5aR in Jurkat cells before treatment with LukS‐PV. Cell apoptosis was analyzed by staining with Annexin V/propidium iodide or Annexin V‐PE/7‐AAD. Mitochondrial membrane potential (MMP) was determined using JC‐1 dye. The expression of apoptosis‐associated genes and proteins was identified by qRT‐polymerase chain reaction and Western blotting analysis, respectively. As the C5aR antagonist concentration increased, the rate of apoptosis induced by LukS‐PV decreased, the MMP increased, and expression of pro‐apoptotic Bax and Bak genes and proteins was downregulated while that of anti‐apoptotic Bcl‐2 and Bcl‐x genes and proteins was upregulated. Knockdown of C5aR also decreased LukS‐PV–induced THP‐1 cell apoptosis. LukS‐PV did not induce apoptosis of Jurkat cells, which have no endogenous C5aR expression; however, LukS‐PV did induce apoptosis in Jurkat cells after overexpression of C5aR. Correspondingly, the MMP decreased and Bax and Bak were upregulated while Bcl‐2 and Bcl‐x were downregulated. LukS‐PV can induce apoptosis in AML cells by targeting C5aR. C5aR may be a potential therapeutic target for AML and LukS‐PV is a candidate targeted drug for the treatment of AML.

[Analysis of blood flow energy characteristics of pulsatile and non-pulsatile flow during extracorporeal circulation]

Objective: To analyze the magnitude of blood flow energy and characteristics of frequency domain between pulsatile flow and nonpulsatile flow during cardiopulmonary bypass and physiological flow. Methods: From January 2017 to December 2017, 60 cases of patients with mitral valve disease scheduled for mitral valve replacement or repair at Department of Cardiasurgery, Shanghai Chest Hospital, Shanghai Jiaotong University were randomly divided into 2 groups: pulsatile perfusion (PP) and non-pulsatile perfusion (NP). The magnitude of blood flow energy during pulsatile and non-pulsatile was calculated using energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE) while fast Fourier transformation (FFT) was used to perform power spectral density analysis to identify the frequency domain characteristics between artificial and physiological flow (prior to CPB). The data was analyzed by analysis of variance or t test. Results: At the different time-points after occlusion, the EEP and SHE in PP group were respectively 1.52 to 1.62 and 2.03 to 2.22 times higher than NP at the distal of artery filter. The power density analysis revealed that the blood flow energy of physiological pulsatile flow patterns was within 40 Hz and the ratio of low frequency energy was more than 90% before clamp. The spectral energy ratio of low frequency decreased in both group compared with physiological flow was more obvious in NP group at the radial artery. The ratio of estimated value of power density of PP and NP groups analysis showed the corresponding 0 to 5 Hz, 0 to 10 Hz, 0 to 40 Hz frequency range values measured at the radial artery and filter were 9.51, 4.68, 3.59 and 3.87, 2.69, 2.38 respectively after occulusion. In each frequency range, the energy of PP is higher than that of NP, and the lower the frequency, the greater the difference. The ratio of estimated value of power density of PP and NP groups for the three frequencies measured at the radial artery before and after occlusion were 2.86, 2.83, 2.75 and 14.70, 12.74, 9.85 respectively, and decreased significantly in NP group and low frequency energy. The ratio of estimated value of power density of PP and NP groups under the three different frequencies measured at the radial artery and filter were 26.35, 33.15, 37.36 and 37.41, 54.18, 56.64 respectively, in the conduction process from filter to radial artery, energy exhaustion is significant, especially in group NP. Conclusions: The PP provides significantly more energy than the NP whereby the PP is closer to the physiological pulsatile on the energy frequency structure and attenuation characteristics, with mainly low frequency energy of 0 to 5 Hz and weak energy attenuation. The energy loss of non-pulsatile flow is obvious, especially the low frequency energy.

LukS-PV-Regulated MicroRNA-125a-3p Promotes THP-1 Macrophages Differentiation and Apoptosis by Down-Regulating NF1 and Bcl-2

BACKGROUND/AIMS

LukS-PV is a component of Panton-Valentine leukocidin (PVL). We have previously demonstrated that LukS-PV potently promoted differentiation and induced apoptosis in THP-1 cells. However, the precise mechanisms of these actions remain unknown. MicroRNAs (miRs) play important roles in cellular differentiation and apoptosis. This study aimed to investigate the role of miR-125a-3p in LukS-PV-regulated differentiation and apoptosis and its underlying mechanism in THP-1 cells.

METHODS

MicroRNA profiling analyses were conducted to determine differential miRNA expression levels in THP-1 cells treated with LukS-PV. Cell differentiation and apoptosis were measured in THP-1 cells by gain-of-function and loss-of-function experiments. Bioinformatics analysis and luciferase reporter assays were used to confirm the targets of miR-125a-3p. The effects of the miR-125a-3p targets on cellular differentiation were determined by knocking them down.

RESULTS

MiR-125a-3p was up-regulated after treating the human monocytic leukaemia cell line THP-1 with LukS-PV. In addition, miR-125a-3p positively regulated apoptosis and differentiation in THP-1 cells treated with LukS-PV. Concordantly, luciferase reporter assays confirmed that neurofibromatosis type 1 (NF1) and B-cell lymphoma 2 (Bcl-2) were direct target genes of miR-125a-3p. Moreover, NF1 knockdown in THP-1 cells significantly promoted differentiation in vitro. Finally, the extracellular signal-regulated kinase (ERK) pathway, a downstream target of NF1, was activated after NF1 knockdown.

CONCLUSIONS

These findings confirm that miR-125a-3p is involved in LukS-PV-mediated cell differentiation and apoptosis in THP-1 cells.

[Effects of chronic intermittent hypoxia on left ventricular myocardial contractibility in a rabbit model of obstructive sleep apnea]

Objective: To explore the effects of chronic intermittent hypoxia (CIH) on left ventricular myocardial contractibility in a rabbit model of obstructive sleep apnea (OSA). Methods: Based on random number table, twenty-four rabbits were randomly divided into three groups: operation, sham, and control groups, each with 8 rabbits. The rabbit model for OSA in operation group was established by repeatedly closing the airway and then reopening it. Upper airway obstructions were conducted on rabbits every day, which were alternately closed for 15 s and then reopened for 75 s in a 90 s-long cycle, for 8 h each day over 3 months. The sham rabbits were subjected to the same surgical procedure but no airway obstructions were applied. The control animals were subjected to no intervention. The blood pressure, left ventricular function parameters were assessed before and after the experiment. And the relative expressions of myosin heavy chain α/β (α-MHC and β-MHC) mRNAs in myocardium were observed for all rabbits by real time fluorescent quantitative polymerase chain reaction 3 months later. Results: After 3 months, all rabbits in the operation group manifested sleepiness and the blood pressure rose gradually [(114.25±4.20) vs (93.88±2.10) mmHg, P<0.01]. Compared with the sham operation and the control groups, the left ventricular end-systolic volume [(6.05±1.62) vs (2.83±0.49) and (2.74±0.32) ml, P<0.001] and the left ventricular end-diastolic volume [(1.61±0.78) vs (0.83±0.13) and (0.82±0.10) ml] in operation group were obviously higher, the left ventricular ejection fraction [(63.9±4.2) % vs (74.3±2.5) % and (75.8±3.8) %], left ventricular fractional shortening [(32.2±2.1) % vs (41.8±1.8) % and (42.1±1.8) %] and stroke volume [(1.46±0.13) vs (1.93±0.21) and (1.98±0.24) ml/s] were decreased (all P<0.001). Besides, the maximal rate of the increase of left ventricular pressure [(4 154±360) vs (6 802±492) and (6 759±206) mmHg/s], the maximal rate of the decrease of left ventricular pressure [(4 994±621) vs (6 330±314) and (6 591±225) mmHg/s] in the operation group decreased markedly, left ventricular end diastolic pressure (LVEDP) increased [(6.5±1.6) vs (3.3±0.8) and (3.2±0.9) mmHg] (all P<0.001). The relative expression of α-MHC mRNA in left ventricular myocardial tissue was lower and the relative expression of β-MHC mRNA was higher in operation group than those in the sham operation and the control groups (P<0.05). There were no significant difference in the relevant indicators of cardiac function, and in the relative expressions of α-MHC mRNA and the β-MHC mRNA between the control group and the sham operation group (P>0.05). Conclusions: Repeated intermittent hypoxia can induce hypertension and myocardial contractibility damage in OSA model rabbit simulating upper airway obstruction.

[Cluster analysis of the clinical presentations in patients with moderate-to-severe obstructive sleep apnea syndrome and its significance]

OBJECTIVE

To analyze subtypes of the clinical presentation of moderate-to-severe obstructive sleep apnea syndrome (OSAS) by cluster analysis and to explore its significance.

METHODS

A retrospective analysis was performed on the data of adult moderate-to-severe OSAS patients, which were diagnosed in Respiratory Department, Renmin Hospital of Wuhan University from October 2012 to October 2015. Fifteen kinds of clinical presentations were included in the cluster analysis, and analysis of characteristic of each cluster was then performed after category.

RESULTS

Patients were classified as three distinct clusters. They were identified as "daytime sleepiness group" , "night insomnia group" and "minimally symptomatic group" , consisting of 450 cases (44.64%), 351 cases (34.82%) and 207 cases (20.54%) of the entire cohort. Members in daytime sleepiness group had the highest probability of daytime sleepiness, tiredness, irritableness and the highest Epworth Sleeping Scale score[329 cases (73.11%), 280 cases (62.22%), 223 cases (49.56%) and (13.50±4.93) points], members in night insomnia group had the highest probability of complaining of insomnia, nocturia, night sweats, apnea and awakening[177 cases (50.43%), 157 cases (44.73%), 130 cases (37.04%), 296 cases (84.33%), 182 cases (51.85%)], the probability of having typical symptoms above was the lowest in minimally symptomatic group, but these patients were more likely to have related comorbidities: hypertension, coronary heart disease, arrhythmia, chronic obstructive pulmonary disease and gastroesophageal reflux disease[118 cases (57.00%), 41 cases (19.81%), 44 cases (21.26%), 34 cases (16.43%), 38 cases (18.36%)]; all above results were significantly higher than the other two groups (P<0.012 5). The rate of diabetes in minimally symptomatic group[28 cases (13.53%)]was also higher but the difference was not statistical significance.

CONCLUSION

Cluster analysis contributes to classify multiple clinical presentations of OSAS patients, which has important significance for recognizing disease heterogeneity and early diagnosis.

[The expression and significance of DDR2 and MMP-13in human middle ear cholesteatoma]

Objective:To ascertain the expression level of discoidin domain receptors 2(DDR2) and matrix metalloproteinase-13(MMP-13) in human middle ear cholesteatoma tissues and further investigate their roles in bone destruction and correlation.Method:Using immunohistochemical S-P method to detect the expression level of DDR2 ,MMP-13 in 30 specimens with middle ear cholesteatoma epithelial tissue and 10 specimens with normal ear epithelial tissues．At the same time,the computer image analysis system was used to detect the expression of the two indexes by the quantitative analysis,analyzing their expression in middle ear cholesteatoma epithelial tissue and the correlation between the extent of bone destruction．Result:The expression of DDR2 and MMP-13 were confirmed in human middle ear cholesteatoma epithelial tissues and normal ear epithelial tissues． The mean optical density of DDR2 and MMP13 in human middle ear cholesteatoma epithelial tissues which were tested by the computer image quantitative analysis system were higher than those in normal ear epithelial tissues(P<0．05).The expression of DDR2 and MMP-13 in middle ear cholesteatoma epithelial tissues were positively correlated(r=0.738,P<0.01).In addition,the two indexes were associated and relative to the extent of bone destruction,the wider the extent of bone destruction was,the higher the expression of both indexes(P<0．05)．Conclusion:DDR2 and MMP-13 may play important roles in bone destruction of human middle ear cholesteatoma．.

Geometrical and morphological optimizations of plasmonic nanoarrays for high-performance SERS detection

Here we present an in-depth and comprehensive study of the effect of the geometry and morphology of nanoarray (NA) substrates on their surface-enhanced Raman scattering (SERS) performance. The high-quality SERS-active NA substrates of various unit shapes and pitches are assembled through electron beam lithography and fabricated by electron beam physical vapor deposition. Good agreement is found on comparing the Raman scattering results with the integrals of the fourth power of local electric fields from the three-dimensional numerical simulations. A novel type of hybrid NA substrate composed of disordered nanoparticles and a periodic NA is fabricated and characterized. The morphology of NAs has little influence on the SERS performance of hybrid NA substrates and they perform better than both their counterparts pure NA and disordered nanoparticle substrates.

Bond-counting rule for carbon and its application to the roughness of diamond (001)

Despite that carbon is tetravalent identical to silicon, first-principles calculations reveal that stable step structures on diamond (001) are entirely different from those on silicon. Moreover, pristine Si(001) is flat; pristine diamond (001) could be rough due to negative step formation energies. A generic bond-counting rule is established, which should apply to most carbon structures where sp2 and sp3 hybrids coexist: e.g., it provides a qualitative account of the step energy order without detailed calculation. Our findings agree with experimental observations.

Dissolution dynamics of NaCl nanocrystal in liquid water

The dissolution dynamics of a NaCl nanocrystal in liquid water was studied using molecular dynamics simulations. The dissolution process was found to start with a Cl(-) ion at a corner site, followed by a Na(+) ion nearby. Both show directional preference in the dissolution path. An ion sequence with alternating charge, i.e., Cl(-), Na(+), Cl(-), Na(+), etc. was found to dominate the dissolution process. This image can be understood from the ionic hydration structures and the Coulomb interaction between the ions.

Ice tessellation on a hydroxylated silica surface

The adsorption of water on a fully hydroxylated silica surface is studied by using density-functional total-energy and molecular dynamics calculations. The (100) surface of beta(alpha)-cristobalite covered by geminal hydroxyls has been taken as the substrate. A well-ordered and stable two-dimensional ice with quadrangular and octagonal patterns of hydrogen bond (H-bond) networks-an ice tessellation-is found on the surface for the first time. With the vibrational recognition, the four water molecules in the quadrangle are found to be bonded by strong H bonds while the quadrangles are connected to each other by weak H bonds. This configuration is the most stable, because all the water molecules are fully saturated with H bonds either to each other or to the surface hydroxyl groups.

Vibrational recognition of hydrogen-bonded water networks on a metal surface

The adsorption of water on Pt(111) surface has been studied with ab initio molecular dynamics simulation. Both the energetics and vibrational dynamics indicate the existence of a well-ordered molecular bilayer on this surface. This conclusion is in contrast to the recent result of water on Ru(0001) surface, but agrees with available experiments. In addition, our calculation identifies two different hydrogen bonds in the bilayer. Both can be directly recognized from the vibrational spectra of the OH stretch modes.

The use of suicide gene systems in vascular cells in vitro

To investigate the efficiency of suicide gene systems on vascular cells, HSV-tk/GCV and EC-CD/5-FC systems were established on vascular endothelial cells in vitro by retroviral transduction. Both modified cell lines were highly sensitive to prodrugs, the IC50 for GCV was less than 0.4 microM, and IC50 for 5-FC was less than 75 microM, while the parental endothelial cells were insensitive even at the highest concentrations of prodrugs in this experiment. Mixed cellular assay showed that significant bystander effect was exhibited in modified endothelial cells. When only 10% or 30% of the mixed cells were tk positive and exposed to 20 microM GCV for 6 days, more than 60% or 90% of the whole population was killed. Similar result was also found in CD positive cells. These results indicated that both HSV-tk/GCV and EC-CD/5-FC systems could efficiently suppress endothelial cell growth in vitro.

[Experimental treatment of brain tumor cells using CD suicide gene]

A negative selection system for glioma gene therapy was established in vitro. C 6 rat glioma cells were infected with recombined retrovirus which contain Escherichia coli cytosine deaminase (EC-CD) gene. The enzyme CD can transform the non-toxic prodrug 5-Fluorocytosine (5-FC) to the highly cellular toxic compound 5-Fluorouracil (5-FU). The growth inhibition studies proved that CD-positive cells were highly sensitive to 5-FC, the IC50 about 3 mumol/L, compared with an IC50 of approximately 6000 mumol/L in parental C 6 cells. Both CD-positive and negative cells were sensitive to 5-FU at very low concentration (IC50 < 1 mumol/L). Mixed cellular assay showed CD-positive cells had "bystander effect" on CD-negative cells when exposed to 5-FC. Our results demonstrate that EC-CD gene should be an efficient suicide gene for the treatment of glioma.

Effect of dietary ascorbic acid on heat-induced eye lens protein damage in guinea pigs

The effect of large intake of dietary ascorbic acid on heat-induced eye lens protein damage has been studied. Male guinea pigs of the Hartley strain were used. Ascorbic acid was administered to the experimental animals in the drinking water. The mean daily ascorbic acid intakes for the control and experimental animals were 10 and 366 mg/kg body weight, respectively. The ascorbic acid level in the lens of the experimental animals was significantly higher than in the controls, but no differences in the content of water-soluble lens proteins were observed. When a solution of water-soluble protein was incubated at 60 degrees C, insoluble aggregates were formed. The loss of water-soluble proteins from the lens of the experimental animals was significantly less than that of the controls. The results indicated that large quantities of dietary ascorbic acid were able to protect lens constituents against heat-induced damage.

[Clinical effects and experimental study on gossypol in endometriosis]

Effects of the gossypol on endometriosis in 12 cases of control were observed. The results showed that the gossypol administered orally was effective in endometriosis patients. The basal body temperature changed from biophase to monophase. Dysmenorrhea disappeared in 11/12 patients. Amenorrhea occurred in 10/12 patients and the ovarian endometrial cyst was shrinkable. Serum progesterone and estradiol were decreased after gossypol administration, but follicle-stimulating hormone and luteinizing hormone were increased evidently. Histochemical and cytochemical observations revealed that the activity of acid phosphate (ACP), nonspecific esterase (NSE) and alkaline phosphate (AKP) in both aberrant uterine endometrium and uterine endometrium in situ were decreased evidently. The above results suggest that the satisfactory therapeutic effect of gossypol on endometriosis may be due to not only the indirect but also the direct action on uterine endometrium.