First comprehensive assessment of dietary chlorinated paraffins intake and exposure risk for the rural population of the Tibetan Plateau, China

Knowledge regarding the occurrence of short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) in foodstuffs and their dietary exposure risks for rural Tibetan residents remains largely unknown. Herein, we collected main foodstuffs (including highland barley, vegetables, Tibetan butter, mutton, and yak beef) across the rural Tibetan Plateau and characterized the CP profiles and concentrations. The highest SCCPs concentrations were detected in Tibetan butter (geometric mean (GM): 240.6 ng/g wet weight (ww)), followed by vegetables (59.4 ng/g ww), mutton (51.4 ng/g ww), highland barley (46.3 ng/g ww), and yak beef (31.7 ng/g ww). For MCCPs, the highest concentrations were also detected in Tibetan butter (319.5 ng/g ww), followed by mutton (181.9 ng/g ww), vegetables (127.0 ng/g ww), yak beef (71.2 ng/g ww), and highland barley (30.3 ng/g ww). The predominant congener profiles of SCCPs were C13Cl7-8 in mutton and yak beef, C10Cl7-8 in Tibetan butter, and C10-11Cl6-7 in highland barley and vegetables. The predominant congener profiles of MCCPs were C14Cl7-9 in all sample types. Combined with our previous results of free-range chicken eggs, the median estimated daily intakes (EDIs) of SCCPs and MCCPs via diet for Tibetan rural adults and children was estimated to be 728.8 and 1853.9 ng/kg bw/day and 2565.6 and 5952.8 ng/kg bw/day, respectively. In the worst scenario, MCCPs might induce potential health risks for rural Tibetan population. To our knowledge, this is the first systematic dietary exposure research of SCCPs and MCCPs in the remote rural areas.

Distribution characteristics and potential ecological risk assessment of heavy metals in soils around Shannan landfill site, Tibet

At present, sanitary landfill is mainly used for domestic waste treatment in Shannan City, Tibet. However, there are few studies on heavy metals in the soil around the landfill in Shannan city. Therefore, the surrounding soil of Luqionggang landfill in Shannan City, Tibet Autonomous Region, is taken as the research object. In the study, the geo-accumulation index method, Nemerow comprehensive pollution index method and potential ecological risk index method are mainly used to evaluate the pollution and risk of heavy metals in the soil around the landfill site. The main results are as follows: The average pH value of the soil around the landfill site is 9.37, belonging to the strong alkaline range. The average values of heavy metals Hg and Ni in soil exceeded the background content, and the average contents of other heavy metals Cu, Pb, Zn, Cr, As and Cd did not exceed the background content. The average content of these eight heavy metals did not exceed the screening value of the national soil environmental quality standard. In the horizontal direction, the average content of heavy metal elements Cu, Cr, Cd, Hg and Ni is relatively high in the west. The average content of heavy metals As, Zn and Pb in the north, east and south is slightly higher than that in the west. And the farther away from the landfill, the less the soil is affected by heavy metals. The evaluation results of geo-accumulation index show that heavy metal Hg is the most affected. The average value of the comprehensive pollution index is 2.969, which is between 2 and 3, belonging to the moderate pollution level. And the west side of the landfill (downstream area) is greatly affected. The evaluation results of potential ecological hazard pollution index show that the potential risk index of single pollutants of heavy metals Cu, Pb, Zn, Cr, Ni, As and Cd belongs to low ecological hazard level, and the potential risk index of single pollutants of heavy metal Hg belongs to relatively heavy ecological hazard level. On the whole, the total potential risk coefficient belongs to medium pollution hazard degree. According to the correlation analysis, there is no significant correlation between heavy metal elements As and Hg and the other six heavy metal elements. In addition, the pollution source of heavy metal As may be mainly soil forming factors and the pollution source of Hg may be mainly human factors.

Comparison and selection of municipal solid waste treatment technologies in Tibet plateau area

The treatment of municipal solid waste has different impacts on the society, economy and environment of a region. It is extremely important to select a municipal solid waste disposal method suitable for the Tibetan Plateau. In the study, social, technical, economic, environmental and municipal solid waste characteristics are selected as comprehensive analysis indicators, and then combined with analytical hierarchy process and technique for order preference by similarity to an ideal solution methods for comprehensive analysis. The results show that the population size, population growth, population density and other indicators account for a large weight, and have a greater impact on the selection of municipal solid waste treatment methods. Through the final analysis, it is believed that the incineration treatment method is better than the landfill treatment method in the Tibetan plateau area.

Environmental, economic, and energy analysis of municipal solid waste incineration under anoxic environment in Tibet Plateau

The first Municipal solid waste incineration (MSWI) plant in Lhasa, Tibet, the plateau region of China, started its operation in 2018. Considering the elevation and extreme climate (low pressure and low oxygen content) in Tibet, noticeable differences may be envisaged compared to MSWI elsewhere. The aim of this study is to evaluate the environmental impacts, economic benefits, and energy efficiency of this MSWI project with three representative MSWI case in plain region using Life cycle assessment (LCA), Cost-benefit analysis (CBA), and energy analysis methods. The result showed that enhancing blast volume and cross-sectional area of the boiler help adapt to the oxygen-deficient environment. GaBi model was employed based on the CML 2001 methodology to perform LCA. LCA shows that the Lhasa MSWI project has lower positive environment impacts than the projects in plain region. More attention is needed for the deficiencies in flue gas emissions of MSWI in the plateau region. CBA shows that the payback period is 11.97 years and the internal rate of return is 8.75%. The energy analysis indicates that the boiler energy efficiency is up to 81.92%. MSWI subject to minor changes seems suitable to Tibetan plateau, and can be deployed further.

Evaluation of genome size and phylogenetic relationships of the Saccharum complex species

"Saccharum complex" is a hypothetical group of species, which is supposed to be involved in the origin of modern sugarcane, and displays large genomes and complex chromosomal alterations. The utilization of restricted parents in breeding programs of modern cultivated sugarcane has resulted in a genetic blockage, which controlled its improvement because of the limited genetic diversity. The use of wild relatives is an effective way to broaden the genetic composition of cultivated sugarcane. Due to the infrequent characterization of genomes, the potential of wild relatives is diffused in improving the cultivated sugarcane. To characterize the genomes of the wild relatives, the genome size and phylogenetic relationships among eight species, including Saccharum spontaneum, Erianthus arundinaceus, E. fulvus, E. rockii, Narenga porphyrocoma, Miscanthus floridulus, Eulalia quadrinervis, and M. sinensis were evaluated based on flow cytometry, genome surveys, K-mer analysis, chloroplast genome sequencing, and whole-genome SNPs analysis. We observed highly heterozygous genomes of S. spontaneum, E. rockii, and E. arundinaceus and the highly repetitive genome of E. fulvus. The genomes of Eulalia quadrinervis, N. porphyrocoma, M. sinensis, and M. floridulus were highly complex. Phylogenetic results of the two approaches were dissimilar, however, both indicate E. fulvus displayed closer relationships to Miscanthus and Saccharum than other species of Saccharum complex. Eulalia quadrinervis was more closely related to M. floridulus than M. sinensis; E. arundinaceus differ significantly from Miscanthus, Narenga, and Saccharum, but was relatively close to Erianthus. We proved the point of E. rockii and E. fulvus should not be classified as one genus, and E. fulvus should be classified as the Saccharum genus.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03338-5.

Agent-assisted electrokinetic treatment of sewage sludge: Heavy metal removal effectiveness and nutrient content characteristics

Sewage sludge (SS) is rich in nutrient elements such as phosphorus (P), nitrogen (N), and potassium (K), and therefore a candidate material for use in agriculture. But high content of heavy metals (HMs) can be a major obstacle to its further utilization. Therefore, an appropriate HM removal technology is required before its land application. In this study, an innovative biodegradable agent (citric acid, FeCl₃, ammonium hydroxide, tetrasodium iminodisuccinate (IDS), and tea saponin) assisted electrokinetic treatment (EK) was performed to investigate the HM removal efficiency (R_HMs) and nutrient transportation. Citric acid, IDS, and FeCl₃-assisted EK showed a preferable average R_HMs (R_ave) reduction of 52.74-59.23%, with low energy consumption. After treatment, the content of Hg (0.51 mg kg^-1), Ni (13.23 mg kg^-1), and Pb (26.45 mg kg^-1) elements met the criteria of national risk control standard, in all cases. Following the treatment, most HMs in SS had a reduced potential to be absorbed by plants or be leached into water systems. Risk assessment indicated that the Geoaccumulation index (I_geo) value of HMs has decreased by 0.28-2.40, and the risk of Pb (I_geo=-0.74) reduced to unpolluted potential. Meanwhile, no excessive nutrient loss in SS occurred as a result of the treatment, on the contrary, there was a slight increase in P content (18.17 mg g^-1). These results indicate that agent-assisted EK treatment could be an environmentally-friendly method for R_HMs and nutrient element recovery from SS, opening new opportunities for sustainable SS recycling and its inclusion into circular economy concepts.

Short-Chain Fatty Acids Production from Anaerobic Fermentation of Sewage Sludge: The Effect of Higher Levels Polyaluminium Chloride

With the annual increase in the sludge production in China's sewage treatment plants, the problem of sewage sludge treatment and disposal is becoming more and more serious. Anaerobic fermentation can convert complex organic matter in sewage sludge into short-chain fatty acid, hydrogen, methane and other resources and is an effective method for sewage sludge treatment and disposal. At the same time, sewage sludge often contains flocculants, which will inevitably affect the effect of anaerobic fermentation. As a high-performance flocculant, polyaluminum chloride (PAC) is widely used in wastewater treatment and sewage sludge dewatering processes. Previous studies indicated that lower levels of PAC inhibit the effect of the anaerobic fermentation process of sewage sludge; on the other hand, it is necessary to understand the effects of higher levels of PAC in anaerobically fermented sewage sludge. The results showed that higher levels (0.2-1 g Al/g total solids (TS)) of PAC could promote acid production from anaerobically fermented sewage sludge. Moreover, mechanism studies suggest that higher levels (0.2-1 g Al/g total solids (TS)) of PAC caused excessive adsorption of the charge on the surface of the sewage sludge colloid and reversed the charge. The sewage sludge colloid was stabilized again, which increases the concentration of soluble proteins, polysaccharides, and soluble extracellular polymers (S-EPS) in the fermentation broth, thereby improving the anaerobically fermented sewage sludge efficiency. The results provided from this study may act as technical reference and guidance for the engineering application of sewage sludge anaerobic fermentation.

Characterization of municipal solid waste incineration and flue gas emission under anoxic environment in Tibet Plateau

Waste incineration is a process of full combustion reaction between waste and oxygen at high temperature. It is a new problem whether the special natural environmental conditions of Tibet Plateau, such as low air pressure, low oxygen content, and low temperature, will affect the waste incineration in the plateau area. In this work, the influence of different parameters on MSW incineration efficiency and flue gas emission were investigated. The results showed that the temperatures exhibited a significant impact on the flue gas emission. Under the lower temperature, CO was determined to be the main pollutant. With the increase of temperature, NOx became the main pollutant. The optimal temperature range of flue gas emission was between 800 and 900°C. A slight negative pressure in incinerator was benefit for incineration system safety and flue gas emissions. The optimal range was -50 to 0Pa. Lower oxygen content (3-6%) in the incinerator affected the incineration efficiency and flue gas emission. Meanwhile, the high oxygen content had no obvious impact on the flue gas emission, but the cost increased and the service life of the incinerator was affected. The optimal oxygen content in the incinerator was controlled at 6-8%. Furthermore, the air temperatures, pressures, and oxygen content in the natural environment had no significant effect on MSW incineration process. Increasing the air volume would bring about the increase of N₂ in the incinerator. This work provides the basic data support for MSW incineration technology in plateau area.

Contamination, ecological and health risks of trace elements in soil of landfill and geothermal sites in Tibet

Due to the utilization of landfill technology and geothermal energy production in Tibet, the contamination of the soils and underground water by trace element has currently become a serious problem, both ecologically and to the human health point of view. However, relevant studies concerning this critical problem, particularly in the Tibet area has not been found. Therefore, this study investigated the soil contamination and the spatial distribution of the trace elements in the areas surrounding the Tibetan landfill sites (LS) and geothermal sites (GS) through several pollution evaluation models. In addition, the possible sources of trace elements and their potential impact on public health were also investigated. Results showed that the trace elements in soils nearby LS and GS had moderate to high contamination risk. In soils surrounding LS, mercury had the highest concentration of 0.015 mg/kg and was 6 times higher than the background value of 0.008 mg/kg while in GS, arsenic had the highest concentration of 66.55 mg/kg, and exceeded the soil contamination risk value of 25 mg/kg. Maizhokunggar LS was the most polluted site with an average pollution load index value of 2.95 compared to Naqu, Nyingchi, Shigatse, and Lhasa. 42% of LS were with considerable ecological risk, and all GS had low ecological risk. Both carcinogenic and non-carcinogenic risk for children and adults (male, female) were within the acceptable range. According to the source analysis, unscientific anthropogenic activities including accumulated MSW, industrial discharges, and vehicle emissions significantly contributed 51.83% to soil trace element contamination. Considering that Tibet is an environment-ecologically vulnerable region with very weak self-adjustment ability, accumulated municipal solid waste in the landfill sites should be well disposed of, and even soil remediation should be well implemented.

Characteristics and management modes of domestic waste in rural areas of developing countries: a case study of China

A huge accumulation of domestic waste has caused serious environmental contamination in rural areas of developing countries (RADIC). The characteristics and management of domestic waste are carefully discussed, based on field surveys and a literature review. The results indicate that the generation in most of RADIC is less than the median of 0.521 kg day^-1 per capita in China, and much smaller than in rural areas of developed countries (RADEC). Organic waste and inert waste with an accumulative mass percentage of 72.31% are dominant components of domestic waste in the rural areas of China. There are trends of increasing amounts of kitchen waste, paper/cardboard, and plastic/rubber and a decreasing trend of ash waste. The RADIC composition of domestic waste had a high content of organic waste and a low content of recyclable waste compared to the RADEC. Domestic waste has good compressibility and a light bulk density ranging from 40 to 650 kg m^-3. The moisture, ash, combustible, and calorific values of domestic waste were 53.31%, 18.03%, 28.67%, and 5368 kJ kg^-1, respectively. The domestic waste has an abundance of nutrients including organic matter (39.05%), nitrogen (1.02%), phosphorus (0.50%), and potassium (1.42%). In RADIC, domestic waste can be used as an agricultural manure only after it has been collected and sorted for the potential risk of heavy metal accumulation. Based on these characteristics of domestic waste and the different situations of rural areas, four waste management modes including centralized treatment, decentralized treatment, group treatment, and mobile treatment are designed and discussed.

Estimation and emissions from crop straw and animal dung in Tibet

Based on the statistics data, this paper estimated the quantity of biomass resource, and then the distribution of emissions from its combu3stion and gasification was analyzed in Tibet in 2015. The main conclusions are as follows: (1) biomass energy is rich in Tibet and its geographical distribution and quantity mainly depends on the relationship between ecological zones and the climate conditions. Crop straw is mainly distributed in Xigazê, Lasha, Qamdo and Shannan with the total quantity of 3.29×10⁶t/year; while animal dung is mainly distributed in Nagqu, Qamdo and Xigazê with the total quantity of 1.69×10⁷t/year. For the acquirable quantity of crop straw and animal dung is 7.27×10⁶t/year, mainly distributed in Nagqu, Qamdo and Xigazê. (2) The energy production potential of crop straw and animal dung in Tibet for combustion (thermal efficiency: 22.5%), HLG (system efficiency: 28.75% based on our investigation) and VLG (system efficiency: 38.75%) is 2.56×10¹⁰J/year, 3.28×10¹⁰J/year and 4.42×10¹⁰J/year, respectively. (3) Compared to the household combustion, the reduction of SO₂ is 72% with HLG and 97% with VLG, and the NOx reduction is 79% with HLG, 96% with VLG and 72% with gasification-combustion case.

Air gasification of biogas-derived digestate in a downdraft fixed bed gasifier

Digestate is a byproduct from biomass anaerobic digestion process. Gasification of dried digestate to produce gasesous product might be a promising route. In this work, air gasification of digestate with high ash content was performed in a downdraft fixed bed gasifier at temperature varying from 600°C to 800°C and air equivalence ratio (ER) ranging from 0.25 to 0.30. The ash melting properties were firstly detected by the Intelligent Ash Melting Point Test, and the by-products (biochar and ash) were analyzed. The results showed that no ash slagging was observed and therefore it is feasible to operate digestate gasification under 800°C and ER ranging from 0.25 to 0.30. High temperature favored gas production, 800°C is proposed for digestate gasification in the present study. ER with a medium value improved gas quality and cold gas efficiency (CGE), and the optimal LHV of 4.78MJ/Nm³ and CGE of 67.01% were obtained with ER of 0.28. High ER favored the increase of gas yield and decrease of tar concentration, and the optimal gas yield of 2.15 Nm³/kg and tar concentration of 1.61g/Nm³ were achieved with ER of 0.30. Improved molar ratio of H₂/CO varying from 1.03 to 1.08 was obtained at 800°C, indicating gaseous product has the potential for chemical synthesis processes (1<H₂/CO<2). The byproducts biochar and ash could be applied on land as fertilizer.

Transcriptome reveals the overexpression of a kallikrein gene cluster (KLK1/3/7/8/12) in the Tibetans with high altitude-associated polycythemia

High altitude-associated polycythemia (HAPC) is a very common disease. However, it the disease is still unmanageable and the related molecular mechanisms remain largely unclear. In the present study, we aimed to explore the molecular mechanisms responsible for the development of HAPC using transcriptome analysis. Transcriptome analysis was conducted in 3 pairs of gastric mucosa tissues from patients with HAPC and healthy residents at a similar altitude. Endoscopy and histopathological analyses were used to examine the injury to gastric tissues. Molecular remodeling was performed for the interaction between different KLK members and cholesterol. HAPC was found to lead to morphological changes and pathological damage to the gastric mucosa of patients. A total of 10,304 differentially expressed genes (DEGs) were identified. Among these genes, 4,941 DEGs were upregulated, while 5,363 DEGs were downregulated in the patients with HAPC (fold change ≥2, P<0.01 and FDR <0.01). In particular, the kallikrein gene cluster (KLK1/3/7/8/12) was upregulated >17-fold. All the members had high-score binding cholesterol, particularly for the polymers of KLK7. The kallikrein gene cluster (KLK1/3/7/8/12) is on chromosome 19q13.3-13.4. The elevated levels of KLK1, KLK3, KLK7, KLK8 and KLK12 may be closely associated with the hypertension, inflammation, obesity and other gastric injuries associated with polycythemia. The interaction of KLKs and cholesterol maybe play an important role in the development of hypertension. The findings of the present study revealed that HAPC induces gastric injury by upregulating the kallikrein gene cluster (KLK1/3/7/8/12), which can bind cholesterol and result in kallikrein hypertension. These findings provide some basic information for understanding the molecular mechanisms responsible for HAPC and HAPC-related diseases.

Comparative Analysis of Gut Microbiota of Native Tibetan and Han Populations Living at Different Altitudes

The factors driving the composition of gut microbiota are still only partly understood but appear to include environmental, cultural, and genetic factors. In order to obtain more insight into the relative importance of these factors, we analyzed the microbiome composition in subjects of Tibetan or Han descent living at different altitudes. DNA was isolated from stool samples. Using polymerase chain reaction methodology, the 16S rRNA V1-V3 regions were amplified and the sequence information was analyzed by principal coordinates analysis and Lefse analyses. Contrasting the Tibetan and Han populations both living at the 3600 m altitude, we found that the Tibetan microbiome is characterized by a relative abundance of Prevotella whereas the Han stool was enriched in Bacteroides. Comparing the microbiome of Han stool obtained from populations living at different altitudes revealed a more energy efficient flora in samples from those living at higher altitude relative to their lower-altitude counterparts. Comparison of the stool microbiome of Tibetan herders living at 4800 m to rural Tibetans living at 3600 m altitude shows that the former have a flora enriched in butyrate-producing bacteria, possibly in response to the harsher environment that these herders face. Thus, the study shows that both altitude and genetic/cultural background have a significant influence on microbiome composition, and it represents the first attempt to compare stool microbiota of Tibetan and Han populations in relation to altitude.

Characteristics and management of domestic waste in a rural area of the Tibetan Plateau

In the rural area of the Tibetan Plateau (RATP), the characteristics of domestic waste, people's environmental awareness, people's willingness to pay and their influence factors were firstly studied by questionnaires, field samplings and laboratory tests. The results showed that, in the RATP, the generation of domestic waste was 85 g•d-1 per capita and it was mainly composed of plastics, inert waste, kitchen waste, glass and paper. The waste bulk density, moisture content, ash, combustible and low calorific value were 65 kg•m-3, 19.25%, 44.90%, 35.85% and 10,520 kJ•kg-1 respectively. These characteristics are influenced by income sources and geographical position to some extent. Classified collection should be promoted widely on the household and the village basis. Compost, fermentation, landfill, bioreactor landfill and semi-aerobic landfill have been approved as effective techniques to treat domestic waste, except incineration. The distance of 50-800 m between each collection facility and the disposal fee of around $0.8 per month per household are suggested. For suburbs or large population villages, it's better to treat domestic waste by the centralized way. But for the remote rural areas, a decentralized way is proposed. Significantly, the educational and economic influence should be considered into an effective domestic waste management program.

IMPLICATIONS

The current situatio n of the environment in the rural areas of the Tibetan Plateau (RATP) was surveyed. There, the generation of organics and moisture of domestic waste were low but ash, recyclables, and combustibles were high. People's knowledge of domestic waste was absent but their participation in management was strong. Based on the current situation, compost, fermentation, and landfill were effective but incineration was inappropriate. Also, a localized mini landfill for a cluster of villages and or settlements was the best method there.

Transcriptome Reveals 1400-Fold Upregulation of APOA4-APOC3 and 1100-Fold Downregulation of GIF in the Patients with Polycythemia-Induced Gastric Injury

High-altitude polycythemia (HAPC) inducing gastric mucosal lesion (GML) is still out of control and molecular mechanisms remain widely unknown. To address the issues, endoscopy and histopathological analyses were performed. Meanwhile, microarray-based transcriptome profiling was conducted in the gastric mucosa from 3 pairs of healthy subjects and HAPC-induced GML patients. HAPC caused morphological changes and pathological damages of the gastric mucosa of GML patients. A total of 10304 differentially expressed genes (DEGs) were identified, including 4941 up-regulated and 5363 down-regulated DEGs in gastric mucosa of GML patients compared with healthy controls (fold change ≥2, P<0.01 and FDR <0.01). Particularly, apolipoprotein genes APOA4 and APOC3 were 1473-fold and 1468-fold up-regulated in GML patients compared with the controls. In contrast, gastric intrinsic factor (GIF) was 1102-fold down-regulated in GML patients compared with the controls. APOA4 (chr11:116691770–116691711), APOC3 (chr11:116703530–116703589) and GIF (chr11:59603362–59603303) genes are all located on chromosome 11. APOA4 and APOC3 act as an inhibitor of gastric acid secretion while gastric acid promotes ulceration. GIF deficiency activates a program of acute anemia, which may antagonize polycythemia while polycythemia raises the risk of GML. Therefore, the present findings reveal that HAPC-induced GML inspires the protection responses by up-regulating APOA4 and APOC3, and down-regulating GIF. These results may offer the basic information for the treatment of HAPC-induced gastric lesion in the future.

CD14 knockdown reduces lipopolysaccharide-induced cell viability and expression of inflammation-associated genes in gastric cancer cells in vitro and in nude mouse xenografts

The present study examined the role of CD14 in the regulation of lipopolysaccharide (LPS)-induced effects on gastric cancer cells. MGC‑803 cells were stably transfected with CD14 short hairpin (sh)RNA and treated with LPS, followed by assessment of cell proliferation, apoptosis and gene expression using a cell counting kit‑8 assay, flow cytometry, reverse transcription‑polymerase chain reaction and western blot analysis, respectively. The cells subjected to CD14 knockdown were treated with 10 g/ml LPS and injected into nude mice to form tumor xenografts. CD14 shRNA‑transfected MGC‑803 cells did not exhibit any significant changes in cell viability compared with the control cells (P>0.05), but cell viability was markedly increased in the wild‑type (WT) + LPS group (P<0.05). In contrast to the WT + LPS group, the cell viability of the sh‑CD14 + LPS group was markedly decreased (P<0.05). In addition, compared with those in the controls, the level of sh‑CD14 cell apoptosis did not change significantly; however, it was markedly reduced in the LPS group. Compared with that in the WT + LPS group, the rate of apoptosis in the sh‑CD14 + LPS group increased to a certain extent, while it remained lower in the control group. In addition, compared with that in the control, the expression of tumor necrosis factor‑α, interleukin (IL)‑1, IL‑6 and IL‑12, and human β‑defensin 2 was significantly increased in the WT + LPS group, while, compared with that in the WT + LPS group, the expression of these genes was markedly reduced in the sh‑CD14 + LPS group (P<0.05). The nude mouse experiments further confirmed the in vitro data, including the finding that LPS promoted the growth of xenografts, but knockdown of CD14 expression reduced the response of tumor cells to LPS treatment. In conclusion, LPS induced cell viability and the release of inflammatory cytokines, but inhibited gastric cancer cell apoptosis. Knockdown of CD14 expression had no significant effect on gastric cancer malignancy, but mediated LPS signal transduction.

[Research progress of Wnt/β-catenin signaling pathway in prevention and treatment of gastric cancer]

The mechanism underlying the occurrence and development of gastric cancer is complex. Abnormal activation of cell signaling pathways play a vital role in the occurrence and development of cancer. The Wnt/β-catenin signaling pathway participates in gastric cancer cell proliferation, invasion and metastasis and effectively induces drug resistance of the gastric cancer cells; it is also the key signal to mediate gastric carcinogenesis. Disturbances of Wnt/β-catenin signaling pathway can inhibit the growth, invasion and metastasis of gastric cancer and increase the sensitivity of the cancer cells to chemotherapeutic drugs. The authors reviewed the research progress of the role of Wnt/β-catenin signaling pathway in the occurrence and development of gastric cancer and discussed the prospective of preventing gastric cancer by interfering with Wnt/β-catenin signaling pathway.

Gastric cancer stem cells in gastric carcinogenesis, progression, prevention and treatment

In recent decades, the study of the mechanism of tumorigenesis has brought much progress to cancer treatment. However, cancer stem cell (CSC) theory has changed previous views of tumors, and has provided a new method for treatment of cancer. The discovery of CSCs and their characteristics have contributed to understanding the molecular mechanism of tumor genesis and development, resulting in a new effective strategy for cancer treatment. Gastric CSCs (GCSCs) are the basis for the onset of gastric cancer. They may be derived from gastric stem cells in gastric tissues, or bone marrow mesenchymal stem cells. As with other stem cells, GCSCs highly express drug-resistance genes such as aldehyde dehydrogenase and multidrug resistance, which are resistant to chemotherapy and thus form the basis of drug resistance. Many specific molecular markers such as CD44 and CD133 have been used for identification and isolation of GCSCs, diagnosis and grading of gastric cancer, and research on GCSC-targeted therapy for gastric cancer. Therefore, discussion of the recent development and advancements in GCSCs will be helpful for providing novel insight into gastric cancer treatment.

Association of CD14/-260 polymorphism with gastric cancer risk in Highland Tibetans

AIM: To investigate the relationship between CD14-260 and -651 polymorphisms and the risk of developing gastric cancer.

METHODS: DNA was extracted from peripheral blood samples obtained from 225 Tibetans with gastric cancer and 237 healthy Tibetans, and analyzed using the polymerase chain reaction/ligase detection (PCR/LDR) method to determine the genotypes at -260 and -651 loci of the CD14 promoter. The allele frequencies, genotype frequencies, and haplotypes were analyzed for their association with gastric cancer risk using online SHEsis software. The luciferase reporter assay and point mutation analysis were used to construct in vitro plasmids expressing a C/T homozygote at the -260 locus of the CD14 promoter.

RESULTS: The frequencies of CC, CT and TT genotypes in the CD14-260 C/T locus in gastric cancer patients were 19.1%, 38.7% and 42.2%, respectively, whereas they were 33.3%, 32.5% and 34.2%, respectively, in healthy control subjects. CT genotype carriers were more frequently found among gastric cancer patients than healthy controls (OR = 2.076; 95%CI: 1.282-3.360). Also, TT genotype carriers were more frequently found among gastric cancer patients (OR = 2.155; 95%CI: 1.340-3.466). Compared to the C allele of CD14/-260, the T allele was associated with an increased risk for gastric cancer (OR = 1.574; 95%CI: 1.121-2.045). Furthermore, the frequencies of CC, CT and TT in the CD14-651 C/T locus in gastric cancer patients were 64.4%, 29.3% and 6.2%, respectively, while they were 56.5%, 35.0% and 8.4%, respectively, in the healthy control subjects (P > 0.05). Data obtained using the luciferase reporter assay showed that the p260T homozygote was associated with greater CD14 promoter activity (P < 0.01).

CONCLUSION: CD14/-260 polymorphism is associated with gastric cancer risk in Highland Tibetans and affects CD14 promoter activity, thereby regulating CD14 expression.

CD14 regulates gastric cancer cell epithelial‑mesenchymal transition and invasion in vitro

Cluster of differentiation 14 (CD14) protein functions as a co-receptor with either the Toll-like receptor TLR4 or MD-2 in the detection of bacterial lipopolysaccharide (LPS) and plays a role in the innate immune system. Recently, it was shown to have effects on the regulation of epithelial-mesenchymal transition (EMT). Thus, the present study investigated the effects of CD14 knockdown on the regulation of gastric cancer cell EMT and invasive capacity following treatment with or without LPS. Knockdown of CD14 expression using CD14 shRNA in MGC-803 cells significantly enhanced E-cadherin expression, but reduced N-cadherin and vimentin expression in both LPS-treated and untreated cells. Morphologically, the phenotype of LPS-treated CD14-knockdown cells was altered to a sporadic long spindle shape. Moreover, TNF-α-treated cells were further elongated, connections between cells were reduced, the gap between the cells was increased and the cells were transformed into mesenchymal cells. Furthermore, the invasive capacity of CD14-knockdown cells was significantly lower compared to that of the negative control shRNA-transfected MGC-803 cells. LPS-treated CD14-knockdown cells had significantly lower levels of tumor cell invasive ability when compared to the LPS-treated parental MGC-803 cells. However, addition of TNF-α to LPS-treated CD14-knockdown cells significantly increased tumor cell invasion. This study demonstrated that CD14 promoted tumor cell EMT and invasion through TNF-α, whereas knockdown of CD14 expression inhibited gastric cancer cell invasion and EMT.

Epidemiological features of gastric cancer in a community population in Lhasa

AIM: To analyze the epidemiological features of gastric cancer in a community population in Lhasa to provide a theoretical basis for comprehensive prevention and treatment of gastric cancer in the plateau region.

METHODS: This survey was designed to investigate the incidence and prevalence of gastric cancer in a population in Naiqiong community, which is located in Duilongdeqing county, Lhasa. A total of 9423 subjects participated in this survey on 1 July, 2010. All the participants had an age above 35 years. They selectively underwent either sequence mass screening program for gastric cancer for high-risk population or sequence mass screening program for fecal occult blood test by filling out questionnaires. Disease and death registries were conducted.

RESULTS: The rough incidence of gastric cancer was 64.8/100000 (79.1/100000 for males and 52.0/100000 for females), the rough prevalence was 96.7/100000 (123.9/100000 for males and 72.2/100000 for females), and the rough mortality rate was 31.8/100000 (44.8/100000 for males and 20.2/100000 for females).

CONCLUSION: The incidence of gastric cancer in Lhasa community population is significantly higher than national average level. Effective measures catering to epidemiological features in the plateau region should be implemented to prevent and treat gastric cancer.

Hepatic fibrosis and long-term alcoholism: An analysis of 50 residents in Lhasa

AIM: To study the relationship between hepatic fibrosis and long-term alcoholism of residents in Lhasa area.

METHODS: Fifty individuals with more than 5-year alcoholic history in Lhasa area were involved in the study and 20 without alcoholic history were as control. Associated examinations consisting of liver functions, serum HbsAg, extracellular matrix (ECM) components (type IV collagen and hyaluronic acid, HA) and type B ultrasonic for hepatocholecystic system and spleen were used to assess the liver status.

RESULTS: Fifty individuals in the study group represented symptoms such as congestion of tongue edge, gingival atrophy, icteric sclera, telangiectasis. Ultrasonic examinations showed that the size of left hepatic lobe in the study group was significantly different from that in the control group (6.60±1.14 vs 5.89±0.91, P <0.01). The liver structure, portal vein diameter and liver blood vessels were also showing significant differences (56.0% vs 1.1%, P <0.05). The indexes of liver function such as GGT, AST (2 863±1 513 vs 1 119±644, 993±704 vs 518±271, P <0.01), ALT, TB, DbiL (1 132±970 vs 744±502, 20.5±10.7 vs 18.0±6.0, 5.8±5.6 vs 4.9±2.9, P <0.05) manifested significant differences between the study group and the control group. ECM IV and HA in the study group also showed prominent differences from those in the controls (155±109 vs 87±46, 210±141 vs 92±54, P <0.01).

CONCLUSION: Different degree of liver damage, hepatic structure changes and hepatic fibrosis appear in individuals with long-term alcoholism in Lhasa area. Hepatocellular damage is directly related to the volume of alcohol incepted and duration of alcoholic history. B-ultrasonography and serum biochemistry should be adopted for early diagnosis.

[A clinical study on vaccine of Mycobacterium vaccae in treating pulmonary tuberculosis]

OBJECTIVE

To study the effect of vaccine of Mycobacterium vaccae on cell-mediated immunity and on treating patients with pulmonary tuberculosis.

METHODS

Seventy cases of pulmonary tuberculosis with smear positive and initial treatment were classified randomly into group I (35 cases) and group II (35 cases), receiving 2HRZS/4HR and 2HRZS/4HR plus vaccine of Mycobacterium vaccae regimens respectively. Thirty-one multi-drug resistant pulmonary tuberculosis cases were classified into group III, receiving 4 - 6 sensitive antituberculous drugs and vaccine of Mycobacterium vaccae. Improvement of clinical symptoms, resolution of pulmonary lesions, negative conversion of sputum and changes of immunological functions were observed.

RESULTS

No significant difference in improvement of symptoms was found in group I and group II (P > 0.05), and the improvement rate of clinical symptoms in group III was found more than 50%. X-ray resolution rates in 4th month were 83% and 89%, and cavity reducing rates 40% and 50% respectively in group I and group II, and no significant differences were found (P > 0.05). X-ray resolution rate was 29%, cavity reducing rate 7% and no deteriorated case was found in group III. Sputum negative conversion rates in 1st, 2nd, 3rd and 4th month were 23%, 51%, 83% and 97% respectively in group I, while 31%, 77%, 89% and 100% in group II, and 3%, 16%, 29% and 32% in group III. Significant difference was found between group I and group II in sputum negative conversion rate in 2nd month after treatment (P < 0.05). After treatment, values of lymphocyte transformation test (LTT), CD(3), CD(4) and CD(4)/CD(8) of the above 3 groups were all higher than that before the treatment (P < 0.05), level of tumor necrosis factor decreased in group II and IL-2, IL-6 increased in group III.

CONCLUSIONS

Vaccine of Mycobacterium vaccae is a good immunotherapy preparation, which promotes sputum negative conversion and activation of cell-mediated immunity.

Ultrastructural identification of cells involved in the healing of intramembranous and endochondral bones

This study was designed to identify the cells involved in the healing of autogenous intramembranous (IM) and of endochondral (EC) bone grafts. Thirty-six defects were created in the skull of 18 adult New Zealand White rabbits. Defects were filled with IM graft alone, EC graft alone, demineralized bone matrix (DBM) alone, or combined DBM-IM and DBM-EC bone. Cellular identification was carried out at 7 and 14 days by light and electron microscopy. In IM bone, preosteoblasts, osteoblasts, and osteocytes were observed with no cartilage intermediate stage, while in EC bone, chondroblasts and chondrocytes were observed. DBM implant and DBM-IM were characterized by the presence of a cartilage stage. In conclusion, IM bone healed through an osteogenic ossification route, while EC bone healed through an EC ossification route. In the presence of demineralized EC bone matrix, IM bone adopts an EC ossification route.

Study of natural diamonds by dynamic nuclear polarization-enhanced 13C nuclear magnetic resonance spectroscopy

The results of a study of two types of natural-diamond crystals by dynamic nuclear polarization (DNP)-enhanced high-resolution solid-state 13C nuclear magnetic resonance (NMR) are reported. The home-built DNP magic-angle spinning (MAS) 13C NMR spectrometer operates at 54 GHz for electrons and 20.2 MHz for carbons. The power of the microwave source was about 30 W and the highest DNP enhancement factor came near to 10(3). It was shown that in the MAS spectra the 13C NMR linewidths of the Ib-type diamond were broader than those of IaB3-type diamond. From the hyperfine structure of the DNP enhancement as a function of frequency, four kinds of nitrogen-centred and one kind of carbon-centred free radicals could be identified in the Ib-type diamond. The hyperfine structures of the DNP enhancement curve that originated from the anisotropic hyperfine interaction between electron and nuclei could be partially averaged out by MAS. The 13C polarization time of DNP was rather long, i.e. 1500 s, and the spin-lattice relaxation time (without microwave irradiation) was about 300 s, which was somewhat shorter than anticipated. Discussions on these experimental results have been made in this report.

Nucleotide sequence of a cDNA from Onchocerca gibsoni encoding a novel repetitive antigen

mRNA from uterine microfilariae of the cattle parasite Onchocerca gibsoni was used for the construction of cDNA libraries. A cDNA clone encoding an antigen recognized by serum from human individuals infected with O. volvulus was found to contain five copies of an 87 bp unit. These 87 bp units were present in the genome in high copy number as long tandem arrays. These are the first cDNA sequence data obtained directly from larvae of any Onchocerca species.

[Effect of phentolamine in combination with pituitrin on the hepatic and systemic hemodynamics]

This experimental study was aimed at the effect of phentolamine used separately or in combination with pituitrin on hepatic and systemic hemodynamics in cirrhotic portal hypertensive dogs. The results showed that either of these drugs used separately could lead to reduction of portal venous pressure. Each of the drugs could also cause by-effect on systemic hemodynamics, or reduce hepatic blood flow. When phentolamine was used in combination with pituitrin no side effect was found in hepatic and systemic hemodynamics. It was suggested that phentolamine used in combination with pituitrin could efficiently decrease portal hypertension and counteract the side-effects. It would be useful in treatment of bleeding from esophageal variceal rupture in cirrhotic patients with portal hypertension.