[Introduction of a tool to assess Risk of Bias in Non-randomized Studies-of Environmental Exposure (ROBINS-E)]

This paper summaries the Risk of Bias in Non-randomized Studies-of Environmental Exposure (ROBINS-E), a tool for evaluating risk of bias about non-randomized studies of exposures (NRSE), and introduces the application of ROBINS-E in a published NRSE. According to the characteristics of NRSE, evaluation fields and signaling questions were designed in ROBINS-E to provide essential information about risk of bias for NRSE included in systematic reviews and GRADE. ROBINS-E is the tool in assessment of risk of bias in observational studies and quasi-randomized studies. Although the tool has been used in practice to some extent, but it still needs further improvement. Attention should be paid to its update and progress.

[Introduction to COSMOS-E: Guidance on conducting systematic reviews and Meta-analyses on etiology of observational studies]

This paper introduces the conducting systematic reviews and Meta-analyses of observational studies of etiology (COSMOS-E) and illustrates the critical issues of COSMOS-E with a published systematic review. This document provides researchers with guidance on all steps in systematic reviews of observational studies of etiology, from shaping the research question, defining exposure and outcomes, to assessing the risk of bias and statistical analysis.

[Current global development of screening guidelines for hepatocellular carcinoma: a systematic review]

Objective: The objective of the study was systematically summarized the current status of the hepatocellular carcinoma (HCC) screening guidelines, and evaluated the HCC screening guidelines according to the authoritative framework of cancer screening guidelines of authoritative institutions, which provided important value for the formulation of HCC screening evidence-based guidelines. Methods: Literature search was conducted in multiple databases from their inception dates to January 3, 2019. In addition, we sought relevant websites further was searched to identify potentially eligible studies. Two reviewers independently screened literature and extracted data. Qualitative description of the basic information, recommendations of HCC screening, source of evidence and update progress of the HCC screening guidelines was conducted. Results: At present, there were no independent HCC screening guidelines worldwide. There were only 17 clinical practice HCC guidelines briefly provided the recommendation of HCC screening. Current HCC screening guidelines only recommended screening for high-risk groups of HCC. All guidelines have identified patients with chronic hepatitis B, hepatitis C and cirrhosis as high-risk groups for HCC. Most of guidelines recommended screening intervals was 6 months. The latest guidelines in Europe and the United States recommended ultrasound for screening HCC. The combination of ultrasound and AFP was recommended in the Asian guidelines. Currently, HCC screening guidelines mainly recommended screening strategies based on factors such as risk of HCC, accuracy of screening modality, screening cost, etc.. The key factors such as screening efficacy and safety have not yet been considered comprehensively. Conclusions: There were no independent HCC screening guidelines worldwide. Only some clinical practice HCC guidelines briefly mentioned HCC screening. Currently, the guidelines only recommend screening for high-risk groups of HCC, with a screening interval of 6 months. There are differences in screening modalities recommended by European, American and Asian guidelines for screening HCC. It is suggested that the relevant institutions should formulate the evidence-based HCC screening guidelines by referring to the theoretical framework of other authoritative other cancer screening guidelines.

[Construction of key question list in the evidence-based guidelines for colorectal cancer screening in China]

Objective: To establish the key question list for the development of evidence- based guideline in China according to the content and limitation of current evidence-based guidelines around the world. Methods: First, we introduced the evidence-based guidelines in detail which met the criteria based on World Health Organization guideline development handbook and then formulated the draft list of key questions for the development of evidence-based guidelines. At last, the Delphi method was used to determine the list of key questions in developing evidence-based guidelines of colorectal cancer screening. Results: Totally, 34 questionnaires were collected, with experts from clinical and epidemiological fields. The average experts' authority coefficient was 0.81, indicating a high degree of authority. The concentration of opinions on all items in the questionnaire was relatively high, with the full score ratio greater than 75% and the coefficient of variation less than 0.3. The list of key questions on evidence-based guidelines for colorectal cancer screening has been divided into six parts: epidemiological problems, risk classification, screening age, screening tools, implementation and selection of steering group members, which covers the issues that need to be considered in the development of evidence-based colorectal cancer screening guidelines in China. Conclusion: The key question list for evidence-based guideline development in our study can be applied to the development of evidence-based guidelines for colorectal cancer screening in the future, as well as the development of evidence-based guidelines for other cancer screening in China.

Preparation, morphology and coagulation characteristics of a new polyferric chloride coagulant prepared using pyrite cinders

Pyrite cinders are the main industrial waste generated from the process of sulphuric acid production using pyrite ores. The pyrite cinders may have utilization value in preparing a new polyferric chloride (PFC) coagulant. In order to attain this objective, a preparation method for PFC products from pyrite cinders was studied by a Taguchi orthogonal array experiment. On the basis of the successful preparation, the morphologies and coagulation characteristics of three PFC products, with different basicities, were observed by transmission electron microscopy (TEM) and examined by jar tests, respectively. The results showed that the molar ratio of NaOH to Fe should be in a range between 0.75:1 and 1:1, the molar ratio of stabilizer NaH2PO4 to Fe should be in a range between 0.12:1 and 0.15:1, the curing time should be 2 h, the curing temperature can be 60 degrees C and the molar ratio of NaHCO3 to Fe can be determined according to the basicity required in order to get the optimal stability of PFC products and the best flocculation efficiency. Although the degree of aggregation of the PFC products became larger with the increase in the basicity, the coagulation efficiency could be only improved with an increase in the basicity within a certain range. When the basicity exceeded a certain value, the coagulation efficiency started to decrease. In this study, PFC2 (B = 11.16%) had better coagulation characteristics than either PFCl (B = 6.08%), PFC2 (B = 11.16%), PFC3 (B = 15.92%) or polyaluminium chloride (PAC).

Risk assessment of cadmium-contaminated soil on plant DNA damage using RAPD and physiological indices

Impact assessment of contaminants in soil is an important issue in environmental quality study and remediation of contaminated land. A random amplified polymorphic DNA (RAPD) 'fingerprinting' technique was exhibited to detect genotoxin-induced DNA damage of plants from heavy metal contaminated soil. This study compared the effects occurring at molecular and population levels in barley seedlings exposed to cadmium (Cd) contamination in soil. Results indicate that reduction of root growth and increase of total soluble protein level in the root tips of barley seedlings occurred with the ascending Cd concentrations. For the RAPD analyses, nine 10-base pair (bp) random RAPD primers (decamers) with 60-70% GC content were found to produce unique polymorphic band patterns and subsequently were used to produce a total of 129 RAPD fragments of 144-2639 base pair in molecular size in the root tips of control seedlings. Results produced from nine primers indicate that the changes occurring in RAPD profiles of the root tips following Cd treatment included alterations in band intensity as well as gain or loss of bands compared with the control seedlings. New amplified fragments at molecular size from approximately 154 to 2245 bp appeared almost for 10, 20 and 40 mg L(-1) Cd with 9 primers (one-four new polymerase chain reaction, (PCR) products), and the number of missing bands enhanced with the increasing Cd concentration for nine primers. These results suggest that genomic template stability reflecting changes in RAPD profiles were significantly affected and it compared favourably with the traditional indices such as growth and soluble protein level at the above Cd concentrations. The DNA polymorphisms detected by RAPD can be applied as a suitable biomarker assay for detection of the genotoxic effects of Cd stress in soil on plants. As a tool in risk assessment the RAPD assay can be used in characterisation of Cd hazard in soil.

Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals (HMs) as well as their genotoxicity in soil after long-term wastewater irrigation

A study was carried out on the residue level of major concern pollutants (PAHs, PCBs and HMs) and the assessment of their genotoxicity in soils obtained from Shenyang, northeast of China which had been subjected to wastewater irrigation for more than 40 years. Topsoils (0-20cm) in paddy fields were sampled along the upper, middle and lower reaches of the wastewater disposal channel. Sixteen USEPA PAHs were determined by High Performance Liquid Chromatography (HPLC) with fluorescence detector, eight PCBs were detected by Gas Chromatography (GC) with electron capture detector, and six heavy metals (Cd, Cu, Pb, Zn, Ni, and Cr) were measured by Atomic Absorption Spectrophotometer (AAS). The genotoxicity effect of soils was examined by Vicia faba micronucleus (MN) test. Archived soils that had undergone a similar history of wastewater irrigation provided by Technical University of Berlin, Germany were subjected to analysis of the above pollutants and Vicia faba/MN test for comparison. Results indicated elevated residues of the studied pollutants (PAHs, especially benzo (a) pyrene, the eight PCB congeners and heavy metals) in both tested and archived soils. The MN frequencies were 2.2-48.4 times higher compared with the control. However, there was no correlation between the MN frequencies and the concentration of pollutants detected. This investigation suggested a potential ecological risk even with a lower level of residual pollutants in soil matrix after long-term wastewater irrigation.

Evaluation of heavy metal contamination in Phaeozem of northeast China

Surface and profile Phaeozem soil samples from 31 locations affected by various anthropogenic activities such as mining, chemical manufacturing, traffic emission and pesticide application were collected in Heilongjiang Province and Jilin Province, northeast China. The range of total concentrations of four heavy metals Cd, Pb, Cu and Zn in the soil was 0.011-3.137, 10.31-62.34, 9.74-51.21 and 39.54-247.59 mg kg(-1), respectively, determined using the acidic digestion procedure. Four methods including single contamination evaluation, background concentration comparison, surface/subsurface concentration comparison and exchangeable fraction evaluation were used to evaluate the extent of metal contamination in Phaeozem. The results indicated that different activities increased the concentrations of the heavy metals in surface soils, where high concentrations of cadmium and lead were found close to chemical plants and in the suburbs of the investigated cities. The four methods showed a general trend of increased soil contamination with heavy metals. Cadmium was of the most concern compared with the other contaminated elements in the study area, due to the long-term phosphatic fertilizer utilization and industrial activities. The proper evaluation method for cadmium contamination was the background concentration comparison, while for zinc and copper was the single contaminative index evaluation. Cadmium and lead could be the potential environmental risk in the Phaeozem area based on the different evaluations.

Earthworm cytochrome P450 determination and application as a biomarker for diagnosing PAH exposure

We developed a new microsome purification method and used the Omura and Sato method to measure the total content of cytochrome (Cyt) P450 in earthworm (Eisenia fetida) microsomes. In method development, two different pretreatments, i.e. solubilization or manual separation were used to purify worm microsomes. Solubilization was more effective than manual separation and difference spectra showed a peak at 450 +/- 1 nm in microsomes received solubilization pretreatment. We conducted a 48 h contact test by exposing worms on pyrene (Py) and benzo[a]pyrene (BaP) spiked filter paper. A dose-response relationship was established between total P450 content and the concentration of Py or BaP ranging from 10(-6) mg mL(-1) to 10(-2) mg mL(-1). Results show that total Cyt P450 content in earthworms is a promising biomarker for diagnosing PAHs exposure at sublethal dose ranges.

DNA changes in barley (Hordeum vulgare) seedlings induced by cadmium pollution using RAPD analysis

In recent years, several plant species have been used as bioindicators, and several tests have been developed to evaluate the toxicity of environmental contaminants on vegetal organisms. In this study, barley (Hordeum vulgare L) seedling was used as bioindicator of cadmium (Cd) pollution in the range of 30-120 mgl(-1). Inhibition of root growth and reduction of total soluble protein content in root tips of barley seedlings were observed with the increase of Cd concentrations. The changes occurring in random amplified polymorphic DNA (RAPD) profiles of root tips following Cd treatment included variation in band intensity, loss of normal bands and appearance of new bands compared with the normal seedlings. Additionally, we found that the effect of changes was dose-dependent. These results indicated that genomic template stability (a qualitative measure reflecting changes in RAPD profiles) was significantly affected at the above Cd concentration. Thus, DNA polymorphisms detected by RAPD analysis could be used as an investigation tool for environmental toxicology and as a useful biomarker assay for the detection of genotoxic effects of Cd pollution on plants.

Single and joint effects of acetochlor and urea on earthworm Esisenia foelide populations in phaiozem

Much attention is paid to soil health and environmental safety. Earthworms are an important indicator of soil ecosystem health and safety. Ecological toxicity of acetochlor and excessive urea, in both their single and joint effects, on earthworm Esisenia foelide was thus studied using the soil-culture method. Acetochlor had an enhanced toxicity from low concentration to high concentration. The mortality of earthworms after a 6-day exposure was changed from 0 to 86.7%, and the weight change rate ranged from 7.86 to -30.43%, when the concentration of acetochlor was increased from 164 to 730 mg kg(-1). Urea expressed its positive and beneficial effects on earthworms when its concentration was lower than 500 mg kg(-1). Strongly toxic effects took place when the concentration of urea was higher than 1000 mg kg(-1). The mortality of earthworms exposed to urea reached 100% when its concentration was more than 1500 mg kg(-1). When the concentration of urea was lower than 500 mg kg(-1), there were antagonistic effects between the two agrochemicals on earthworms; when the concentration of urea was higher than 500 mg kg(-1), joint toxic effects of acetochlor and excessive urea on earthworms were synergic. In any case, excessive urea application is very harmful to the health of soil ecosystems.

[Experimental study on ergonomical color matching design of virtual crew cabin layout in manned spacecraft]

Objective. To approach general principles of color matching for crew module layout and to provide its ergonomical evaluation with basic data. Method. First, according to some ergonomic rules a virtual reality experimental system was set up, then 64 subjects of different ages and with some background of spaceflight were offered a color matching example according to their own choice in advance. Finally, all the hues, saturations, and lightnesses of the selected colors and their total number were statistically analyzed by SPSS 8.0 software. Result. After choosing the colors for items (standard cabinets, floor, handrails, supports and etc.) in the crew cabin, the mean kinds of color hue matching in the cockpit was 5. In addition, above half of subjects endorsed the example colors but its saturation and lightness were a little higher than those of the example every time. Although its distribution was discrete, there still was a common agreement on color matching (about 50%). Conclusion. When the color matching of crew module in long time flight was ergonomically designed, generally, cool and warm hues should be taken into consideration, and their total number need be controlled to be under 5 so as to satisfy human psychological characters.

Assay of serum arylesterase activity by fitting to the reaction curve with an integrated rate equation

BACKGROUND

Conventional enzyme activities make use of the initial reaction rate at high substrate concentrations. Because this is not always practical, alternative enzyme assays have been sought.

METHODS

Reaction curve fitting with an integrated rate equation was investigated to assay serum arylesterase (ArE) activity using phenyl acetate (PA) and p-nitrophenol acetate (PNPA) as substrates. At a much lower initial concentration of substrate (S(0)), the simplified integrated rate equation for the ArE reaction was ln(S(0)/S(i))=(V(m)/K(m)+K(d))t(i). Treating S(0) as a parameter, the enzyme activity as V(m)/K(m) was estimated through nonlinear least square fitting to reaction curve, and the multiplication of V(m)/K(m) by K(m) produced V(m). Spontaneous hydrolysis of the substrate with a rate constant, K(d), served as the background for the estimation of V(m)/K(m).

RESULTS

Substrate concentration at 8% of K(m) was well suited for the estimation of V(m)/K(m). With either substrate, the V(m)/K(m) showed a close relation to the percentage of substrate consumed, and was not affected by common systematic errors. With either substrate, the between-run precision for V(m)/K(m) was 6% (n>7), V(m)/K(m) was proportional to the amount of ArE and closely correlated with its initial rate. The upper limit of linearity by this integrated method was much higher than the initial rate method, while the detection limit was comparable. By using either V(m)/K(m) or the initial rate, there was negligible interference with ArE activity assay from triglycerides, bilirubin, and hemoglobin.

CONCLUSIONS

These results indicate the feasibility of the integrated method for routine assay of serum enzyme activity.

Protective effect of nimodipine against cerebral injury induced by subacute carbon monoxide intoxication in mice

AIM

To study the effects of nimodipine on delayed cerebral injury in mice from subacute carbon monoxide (CO) exposure.

METHODS

Mice were exposed to CO (100 mL/kg, ip) once a day, continuously for 7 d. After 7-d CO-exposure, mortality in mice, changes in learning ability and memory using passive avoidance test, the pathomorphologic observation of brain tissue slices, and changes of monoamine oxide (MAO)-B activities in cerebral tissue were studied. Nimodipine was administered 30 min before CO-exposure every time.

RESULTS

The preadministration of nimodipine decreased the mortality in mice, almost reversed the impairment of learning and memory function, prevented the hippocampal neurons against delayed death and blunted the rise of MAO-B activity after subacute CO poisoning of mice.

CONCLUSION

Pretreatment with nimodipine markedly prevented mice from delayed encephalopathy after CO poisoning.

[Ergonomic research on crew module layout in manned spacecraft system]

The structural layout of crew module in manned spacecraft is one of the main factors related to its man-machine interface. Not only the mechanic characters of equipment in it, but also the human engineering factors should be taken into consideration. According to the history of manned spaceflight, the structural layout development, general rules and main objects for research are expounded in detail, on the basis of which some views on its development trends are put forward for discussion.

[Effect of the tetrandrine on morphine induced hyperactivity and reinforcement in mice]

OBJECTIVE

After single administration of morphine and the motion activity was measured by ambulometer, conditioned place-preference paradigm was used to study the reinforcing effect of morphine, climbing behavior was used to evaluate the relation with Dopaminergic system and immediate early expression of c-fos gene was in brain was showed by immunohistochemical method.

RESULTS

Single administration of morphine could induce hyperactivity, repeated treatment would produce a conditioned place-preference response, tetrandrine 30 or 60 mg/kg hypodermic injection could inhibit the morphine induced hyperactivity, 60 mg/kg could inhibit the conditioned place-preference response but no influence on climbing behavior in mice was found. Tetrandrine could inhibit the c-fos gene expression in nucleus accumbens, ventral tegmental and prefrontal cortex in place-preference model formed by morphine.

CONCLUSION

Tetrandrine could inhibit the hyperactivity and conditioned place preference response induced by morphine, it might relate to reducing the c-fos gene expression in special area of brain in mice.

[Expression of FAS and FASL genes in brain and effect of flunarizine on these expressions in rats after global ischemia-reperfusion]

AIM

To explore the expression of Fas and FasL genes after ischemia-reperfusion in rats and the effect of flunarizine.

METHODS

Ischemia was induced by four-vessel occlusion for 30 min following reperfusion in rats. The biopsy tissues from brain were immunohistochemically assayed with Fas and FasL genes polyclonal antibody.

RESULTS

The expression of Fas was increased as early as 6 h after the onset of reperfusion. The peak of the expression of Fas occurred 24-48 h after ischemia-reperfusion. The expression of FasL was observed 12 h after ischemia-reperfusion and peaked at 48-72 h. The expression of Fas and FasL gene was quite obvious in the cortex and hippocampus CA1, the more sensitive areas to ischemic injury. Flunarizine i.p. 10 mg.kg-1 and 20 mg.kg-1 obviously inhibited the expression of Fas and FasL in dose-dependent manner.

CONCLUSION

Expression of Fas and FasL in cerebral cortex and hippocampus can be induced by global ischemia-reperfusion. Flunarizine significantly inhibited the expression of Fas and FasL genes following ischemia-reperfusion.

[Manual operation in manned spacecraft]

The main character of manned spacecraft is that there are astronauts in it. In order to ensure security, reliability and high efficiency of the whole system, it is necessary to make full use of human operation in space environment at the stage of system overall design, especially for long manned flight. On the basis of related data, this paper summarized the principles of manual operation, its main objects and some requirement on man-machine interface. At last, some views have been put forward for discussion.

Protective effects of fructose-1,6-diphosphate against cerebral injury induced by subacute carbon monoxide intoxication in mice

AIM

To study the effects of fructose-1,6-diphosphate (FDP) on delayed cerebral injury in mice from subacute carbon monoxide (CO) exposure.

METHODS

Mice were exposed to CO (100 mL/kg i.p.) once a day, continouUsly for 7 d. After 7-d CO-exposure, mortality of mice, changes in learning ability and memory using passive avoidAnce test, the pathomorphologic observation of brain tissue slices, and changes in monoamine oxide (MAO)-B activities in cerebral tissue were studied. FDP was administrated 30 min before CO-exposure every time.

RESULTS

The preadministration of FDP markedly decreased the mortality of mice, almost reversed the impairment of learning and memory function, prevented the cells from delayed death in hippocampal neurons and blunted the rise in MAO-B activity after subacute CO poisoning of mice.

CONCLUSION

FDP pretreatment markedly prevented mice from delayed encephalopathy after CO poisoning.

Effects of tetrandrine on changes of NMDA receptor channel in cortical neurons of rat induced by anoxia

AIM

To study the effects of tetrandrine (Tet) on the changes of NMDA receptor channels in cortical neurons induced by anoxia.

METHODS

Cell-attached configuration of patch-clamp techniques. Anoxia was produced by perfused cells with 95% N2 + 5% CO2 gassed bath solution.

RESULTS

During anoxia, the open time constant (tau 2), open probability (Po) of 35-pS and 100-pS channels increased. Tet 7.5 mumol.L-1 reduced the Po of 35-pS and 100-pS channels, 15 and 30 mumol.L-1 inhibited open of 100-pS channel fully, and changed the open time constant of 35-pS from two to single exponential distribution.

CONCLUSION

Tet inhibition of the open of NMDA receptor channels induced by anoxia was one of its protective mechanisms.

Effects of ginsenosides on release of [3H]norepinephrine from rat vas deferens and portal vein

The effects of ginsenosides (G) on the release of [3H]norepinephrine ([ 3H]NE) from the isolated rat vas deferens (RVD) and portal vein (RPV) preloaded with [3H]NE were studied, G (100 micrograms/ml) did not affect the spontaneous or high potassium (H-K+, 60 mmol/L)- and tyramine (Tyr 10 mumol/L)-evoked release of [3H]NE, but obviously blunted the phentolamine (Phe 10 mumol/L)-induced increase in [3H]NE release from RVD and enhanced the isoprenaline (Iso 0.1 mumol/L)-augmented [3H]NE release from RPV evoked by H-K+. It is still not known whether G can bind with adrenoceptors. We infer that G may act as a modulator in sensitizing both presynaptic alpha 2- and beta-receptors.