Erratum: HIF-1α or HOTTIP/CTCF Promotes Head and Neck Squamous Cell Carcinoma Progression and Drug Resistance by Targeting HOXA9.

[This corrects the article DOI: 10.1016/j.omtn.2019.12.045.].

Distribution of bacteria infected by metagenomic sequencing technology in maxillofacial space.

OBJECTIVES: This study aimed to compare and analyze the consistency and difference between metageno-mic next-generation sequencing (mNGS) and conventional bacterial culture in the detection of pathogenic microorganisms in maxillofacial space infection, as well as to provide a new detection method for the early clinical identification of pathogenic bacteria in maxillofacial space infection. METHODS: The clinical data of 16 patients with oral and maxillofacial space infections in the First Affiliated Hospital of Zhengzhou University from March 2020 to June 2020 were collected. mNGS and conventional bacterial culture methods were used to detect pus. We then analyzed and compared the test results of the two methods, including the test cycle, positive detection rate, anaerobic bacteria, facultative anaerobes and aerobic bacteria detection rates, distribution of pathogenic bacteria, relative species abundance, and resistance genes. RESULTS: The average inspection period of mNGS was (18.81±3.73) h, and the average inspection period of bacterial culture was (83.25±11.64) h, the former was shorter than the latter (P<0.05). The positive detection rate of mNGS was 100% (16/16), and the positive detection rate of conventional bacterial culture was 31.25% (5/16), the former was higher than the latter (P<0.05). The detection rate of mNGS anaerobic bacteria was 93.75% (15/16), the detection rate of bacterial culture anaerobes was 0 (0/16), the former was higher than the latter (P<0.05). Using mNGS, the detection rate of facultative anaerobes in bacterial culture was 75.00% (12/16), and the detection rate of facultative anaerobes in bacterial culture was 25.00% (4/16), the former was higher than the latter (P<0.05). The detection rate of aerobic bacteria in bacterial culture was 12.50% (1/16), the former was higher than the latter (P>0.05). mNGS detected 15 kinds of pathogenic bacteria, among which 3 were Gram positive, 12 were Gram negative, 49 were non-pathogenic, 16 were Gram positive, and 32 were Gram negative, 1 was fungus. CONCLUSIONS: Compared with conventional bacterial culture, mNGS has the characteristics of short test time, high sensitivity, and high accuracy. Thus, it is a new detection method for the early identification of pathogenic bacteria in maxillofacial space infection and is beneficial to the early clinical diagnosis and treatment of the disease.

HIF-1α or HOTTIP/CTCF Promotes Head and Neck Squamous Cell Carcinoma Progression and Drug Resistance by Targeting HOXA9.

Head and neck squamous cell carcinoma (HNSCC) is the sixth most frequently diagnosed cancer worldwide. However, the clinical outcomes remain unsatisfactory. The aim of this study is to unravel the functional role and regulatory mechanism of HOXA9 in HNSCC. A cohort of 25 HNSCC tumor tissues and normal tissue counterparts was collected. qRT-PCR and western blotting were performed to determine the levels of HOXA9 and epithelial-mesenchymal transition (EMT)-related markers. Cell Counting Kit-8 (CCK-8) and colony formation assays were conducted to monitor cell viability and cytotoxicity. Transwell and wound healing assays were used to determine cell migration and invasion. Annexin V-fluorescein isothiocyanate/propidium iodide (FITC/PI) staining was performed to detect cell apoptosis. Bioinformatic analysis, electrophoretic mobility shift assay and chromatin immunoprecipitation (ChIP) assays were performed to investigate the direct binding between HIF-1α or CCCTC binding factor (CTCF) and HOXA9. Glutathione S-transferase (GST) pull-down and RNA pull-down assays were used to validate the interaction between CTCF and HOTTIP. HOXA9 was upregulated in HNSCC tissues and cells. Knockdown of HOXA9 inhibited cell proliferation, migration, invasion, and chemoresistance but promoted apoptosis in CAL-27 and KB cells. Knockdown of HOXA9 also regulated EMT-related marker via targeting YAP1/ß-catenin. Silencing of HOTTIP or CTCF exerted similar tumor-suppressive effects in HNSCC. Mechanistically, HIF-1α or CTCF transcriptionally regulated HOXA9, and HOTTIP/CTCF cooperatively regulated HOXA9 in KB cells. HIF-1α or HOTTIP/CTCF transcriptionally modulates HOXA9 expression to regulate HNSCC progression and drug resistance.

[Effect of long chain non-coding RNA H19 on the migration and invasion of oral cancer cells and its molecular mechanism].

OBJECTIVE: To investigate the effect of the long chain non-coding RNA H19 (lncRNA H19) on the invasion and migration of oral cancer cells and its related molecular mechanism. METHODS: The expression levels of lncRNA H19, miR-107, and cyclin-dependent kinase 6 (CDK6) in the immortalized oral epithelial cell line HIOEC and the oral cancer cell line CAL27 were detected by real-time quantitative polymerase chain reaction. CAL27 cells were transfected with siRNA H19, miR-107 mimics, pcDNA H19, or anti-miR-107, and the effects of H19 and miR-107 on the invasion and migration of cells were examined via Transwell assay. The TargetScan database predicted the targeting of H19, miR-107, and CDK6. Double luciferase reporter gene assay was performed to detect interactions among H19, miR-107, and CDK6. Western blot analysis was conducted to examine the effects of H19 and miR-107 on the protein level of the target gene CDK6. RESULTS: Compared with that in HIOEC cells, the expression of H19 was significantly increased in CAL27 cells (P<0.05). After transfection with siRNA H19, the expression of H19 decreased, and the invasion and migration ability of CAL27 cells were inhibited (P<0.05). H19 could bind specifically to the 3'-UTR of miR-107 to modulate the expression of miR-107. Compared with that in HIOEC cells, the expression of miR-107 significantly decreased in CAL27 cells (P<0.05). The expression of miR-107 increased after transfection with siRNA H19, and anti-mir-107 co-transfection could promote the invasion and migration ability of siRNA H19 in CAL27 cells (P<0.05). Compared with that in HIOEC cells, CDK6 expression significantly increased in CAL27 cells (P<0.05), and the expression level of the gene was coregulated by H19 and miR-107 (P<0.05). CONCLUSIONS: lncRNA H19 plays an important role in the development of oral cancer. It can regulate the invasion and migration of oral cancer cells by targeting the miR-107/CDK6 signaling axis.

[Role and mechanism of Galectin-3 gene in proliferation, invasion, and apoptosis of oral squamous cell carcinoma].

OBJECTIVE: The effect and mechanism of Galectin-3 gene expression on proliferation, invasion, and apoptosis of oral squamous cell carcinoma (OSCC) were investigated. METHODS: Reverse transcription-polymerase chain reaction (RT-
PCR) and Western blotting were used to detect the mRNA and protein of Galectin-3 gene in OSCC. OSCC Tca8113 was divided into control, negative control, and Galectin-3 transfection groups. Western blotting was used to detect the expression of Galectin-3, matrix metalloproteinase (MMP)-2, MMP-9, Cleaved Caspase-3, ß-catenin, and Cyclin D1 protein after transfection for 48 h in each group. Cell proliferation was detected by CCK8. Cell invasion ability was detected by using a Transwell chamber. Cell apoptosis was detected by flow cytometry. RESULTS: The mRNA and protein expression levels of Galectin-3 gene in OSCC were significantly higher than those in adjacent tissues (P<0.01). Galectin-3 protein expression in Tca8113 cells significantly decreased after RNA interference. Cell survival rate and invasion as well as MMP-2, MMP-9, ß-catenin, and Cyclin D1 protein expression were significantly lower than the blank group. Apoptosis rate and Cleaved Caspase-3 protein expression were significantly higher than the control group (P<0.01). CONCLUSIONS: Inhibition of Galectin-3 gene expression in OSCC can significantly reduce the proliferation and invasion of cancer cells and induce apoptosis. The mechanism is related to downregulation of the Wnt/ß-catenin signaling pathway.

Synthesis and structure of 1-(2-bromo-phen-yl)-2-chloro-3-(2-chloracet-yl)-1H-indole.

In the title indole derivative, C16H10BrCl2NO, the dihedral angle between the mean plane of the indole ring system and the mean plane of the disordered 2-bromo-phenyl ring is 77.6 (1)°. The non-H atoms of the chloracetyl group are essentially coplanar with the indole core. In the crystal, pairs of mol-ecules are face-to-face embraced via two weak C-H⋯O hydrogen bonds, forming inversion dimers with an inter-planar distance between two parallel indole planes of 3.360 (3) Å. These dimers are connected by head-to-head Cl⋯Cl inter-molecular contacts to build a two-dimensional mol-ecular sheet parallel to (101). Neighbouring mol-ecular sheets are stacked together to construct the three-dimensional structure by further short Cl⋯Cl inter-molecular contacts. The atoms of the bromo-phenyl group were refined as disordered over two sets of sites with refined occupancies of 0.61 (2) and 0.39 (2).

[Assessment on the yield loss risk of longan caused by cold damage in South China].

Using daily climate variables gathered from 64 meteorological stations in South China from 1961 to 2012, recognized hazard indicators about disaster grades of cold damage for longan, and methods on agricultural meteorological disasters risk and simulation technology, the yield loss risks of longan caused by cold damage in South China during different developmental periods were assessed. The results showed that during the period of physiologic differentiation of flower bud, the disasters of longan affected by mild cold damage in South China were the most common, followed by severe cold damage and moderate cold damage. The hazards caused by cold damage under different grades varied. In particular, under mild cold damage, light disaster of longan was found in Fujian, followed by Guangdong and Hainan, and Guangxi was serious. Under moderate cold damage, light disaster of longan was found in Hainan, followed by Guangdong and Guangxi, and Fujian was serious. Under severe cold damage, light disaster of longan was found in Hainan, followed by Guangdong and Guangxi, Fujian was serious. During the period of morphologic differentiation of flower bud, the disasters of longan affected by mild cold damage in South China were the most common, followed by severe cold damage and moderate cold damage, while the disasters of longan under mild, moderate and severe cold damages within this period were similar. Specifically, light disasters of longan were all found in Hainan, followed by Guangdong, Guangxi and Fujian. During the period of dormancy, the disaster of longan affected by mild cold damage in South China was the most common, followed by severe cold damage and moderate cold damage. Under mild and severe cold damage, light disaster of longan was found in Fujian, followed by Guangdong and Hainan, and Guangxi was serious. However, under moderate cold damage, light disaster of longan was found in Hainan and Guangxi, followed by Guangdong, and Fujian was serious. At the same level of hazard, the largest risk indices of yield loss of longan during different developmental stages significantly differed. Under mild cold damage, serious disasters of longan were found in the period of physiologic differentiation of flower bud, followed by the period of morphologic differentiation of flower bud and the period of dormancy. However, under moderate and severe cold damage, serious disasters of longan were found in the period of physiologic differentiation of flower bud, followed by the period of dormancy and the period of morphologic differentiation of flower bud.

[The application of microvascular anastomotic device for free flap transfer in reconstruction of oral and maxillofacial defects].

PURPOSE: To evaluate the clinical effect and summarize the experience of vein anastomosis by microvascular anastomotic device in reconstruction of oral and maxillofacial defects. METHODS: From September 2014 to May 2015, twenty-one free flaps were used to repair oral and maxillofacial defects. During surgery, facial artery or supra thyroid artery were selected as feeding arteries, and external jugular vein or the branch of jugular vein was used as the recipient vein. Eighteen arteries of the free flap were anastomosed by hand, 3 arteries and 21 veins were anastomosed by microvascular anastomotic device. The time of anastomosis and patency of vessels were recorded. Statistical analysis was performed using SPSS l7.0 software package. RESULTS: There was no flap necrosis due to venous thrombosis in this series．The facial artery was used as feeding artery 16 times, supra thyroid artery was used 5 times. The external jugular vein was used as reflux vein 13 times, the branch of jugular vein was used 8 times. The duration of artery anastomosis were 17.20±2.31 minutes by hand and 5.48±1.33 minutes by microvascular anastomotic device. The duration of vein anastomosis were 18.39±3.48 minutes by hand and 6.45±0.60 minutes by microvascular anastomotic device. CONCLUSIONS: Application of microvascular anastomotic device can significantly improve the anastomotic speed and vein flow rate. The preliminary results show that blood vessel anastomosis by device is effective and safe.

[Climatic suitability of spring maize planted in the "sickle bend" area of China and regulation suggestion]. / 我国"镰刀弯"地区春玉米种植的气候适宜性与调整建议.

The "sickle bend" area is a typical dry farming and excellent livestock development area, with fragile ecological environment. It includes 13 provinces (autonomous regions) in the north and the southwest of China. The climate suitability and the climatic potential productivity of spring maize from 1981 to 2010 in this area were quantitatively assessed. The daily data from 650 meteorological stations and grid data (1 km×1 km) in the "sickle bend" area from 1981 to 2010, and recognized indicators of agricultural meteorology were used in this study. The agro-ecological zoning mo-del (AEZ) which was currently very popular in estimating crop climatic potential productivity internationally was also applied, as well as land use classification information monitoring from satellite remote sensing. Then, based on biological characteristics of spring maize and agricultural climate resources, scientific countermeasures on reasonably adjusting agricultural production structure in subsuitable and unsuitable areas were proposed. The results showed that: 1) the climatic potential productivity of spring maize in the northern growing areas showed the "big-medium-smaller-small" distribution pattern from the east to the west from 1981 to 2010. However, the climatic potential productivity of spring maize in the southern growing areas had no significant distribution law, fluctuating between "smaller" and " medium " in general. 2) It presented the "most suitable-suitable-subsuitable-unsuitable" distribution pattern from the southeast to the northwest in the northern maize growing region of the "sickle bend" area on the whole from 1981 to 2010. In contrast, the southern planting area showed the "unsuitable-subsuitable-suitable-most suitable" distribution pattern from the southeast to the northwest. The most suitable and suitable planting areas of spring maize were mainly located in the most areas of Northeast China and North China, and the southeastern areas of Northwest China. The subsuitable or unsuitable regions mainly included Inner Mongolia, northern Xinjiang, western Gansu and Guangxi. 3) The most suitable planting area of spring maize was the largest (47%), followed by subsuitable area (23%), unsuitable area (17%) and suitable area (13%). 4) According to the analysis of climatic conditions, we proposed to mainly decrease the spring maize planting in the subsuitable and unsuitable areas. These subsuitable and unsuitable regions were low climatic potential productivity areas, including the arid windstorm region of Northwest, the cold area of Northeast, agro-pastoral area and the rocky desertification region of Southwest.

Developmental expression of the N-myc downstream regulated gene (Ndrg) family during Xenopus tropicalis embryogenesis.

The N-myc downstream regulated gene (Ndrg) family consists of four main members Ndrg1, 2, 3, and 4. The Ndrg genes are involved in many vital biological events including development. However, comprehensive expression patterns of this gene family during vertebrate embryogenesis remain largely unknown. Here, we analyzed the Ndrg family from the evolutionary perspective and examined the expression patterns of the Ndrg genes during Xenopus tropicalis embryogenesis. Different Ndrg family members of vertebrates are separated into different homology clusters which can be further classified into two groups and each Ndrg family member is well conserved during evolution. The temporal and spatial expression patterns of Ndrg1, 2, 3 and 4 are different during early Xenopus tropicalis development. Ndrg1, 2 and 4 are maternally expressed genes while Ndrg3 is a zygotically expressed gene. The Ndrg genes are differentially expressed in the developing central nervous system, the developing sensory organs, and the developing excretory organs. Moreover, they also show other specific expression domains. Our results indicate that the Ndrg genes exhibit specific expression patterns and may play different roles during vertebrate embryogenesis.

[Study on articulation characteristics of patients after cleft palate repair in Henan province].

PURPOSE: To establish the pathological speech characteristic of patients after cleft plate repair in Henan province by unusual speech frequency and vowel formants. METHODS: One hundred normal speech patients and 121 patients after cleft palate repair were selected, their formant frequency of vowels/ a,o,e,i,u,ü/ were obtained. The pathological speech frequency was collected in 121 postoperative patients. The acoustic features of the vowel were compared by SPSS17.0 software package with two independent sample t test. RESULTS: According to articulation position, 21.9% of misarticulation of postoperative patients occurred in dental consonants, 5.2% in retroflex consonants, 21.6% in alveolar consonants, 19.2% in palatal consonants, 12.9% in velar consonants and 6.6% in dorsum consonants. The average value of F2 of/a, o, e, u/did not show significant difference between the two groups (P>0.05).The difference of average value of F2 of /i,ü/ was significant (P<0.05). The average value of F1 of/a, o, e, I, u/did not show significant difference between the two groups (P>0.05).Except /a/,the average value of F3 of vowel /o, e, i, u, ü/showed significant difference between the two groups (P<0.05). CONCLUSIONS: Misarticulation of patients after cleft palate repair in Henan province mainly occurred in dental consonants, alveolar consonants and palatal consonants; tongue over curly can be observed in operated patients with cleft palate. There was no significant difference between the two groups in mouth opening.

Subtractive screen of potential limb regeneration related genes from Pachytriton brevipes.

Regeneration capacity varies greatly among different animal species. In vertebrate, amphibian especially the Urodela, has been used as a powerful model system to study the mechanism of tissue regeneration because of the strong ability to regenerate their damaged or lost appendages. Pachytriton brevipes, a species of newt, which is widely distributed in south of China, can completely restore their damaged limbs within several months. In this study, we use modified suppression subtractive hybridization assay and dot-blot screening to identify candidate genes involved in tissue regeneration in P. brevipes. We successfully isolated 81 ESTs from a forward regeneration subtraction library. And we further verified the differential expression of four candidate genes, Rpl11, Cirbp, Ag2 and Trimx, between regenerating blastema and non-regeneration tissues by in situ hybridization. These genes were also be further characterized by phylogenetic and bioinformatic analysis. In general, we provided a comparative experimental approach to study the mechanisms of vertebrate regeneration.

[Thermal resources and maize temperature suitability in Northeast China under climate change].

This paper analyzed the spatiotemporal patterns of thermal resources and of temperature suitability of maize at its different growth stages in Northeast China, based on the 1951-2100 daily mean and minimum air temperature from RegCM3. In 1951-2100, the thermal resources in Northeast China had an obvious persistent increase, the first day of temperature > or = 10 degrees C continued to be advanced, and the north boundary line in the zone of the first date of temperature > or = 10 degrees C before April 25th moved eastward and northward. In 2071-2100, the first date in some areas of Liaoning Province would advance to March 26th, and the areas with active accumulated temperature > or = 10 degrees C more than 3000 degrees C x d, the length of growth season, and the areas suitable for late-maturing maize planting in Northeast China would increase persistently. In the region, the mean annual temperature in 2011-2100 would be 3.34 degrees C higher than that in 1981-2010. In 1951-2100, there was and would be an increasing temperature suitability of maize at its sowing-heading stage. In 1951-2040, the maize temperature suitability at heading-maturing stage and in whole growth season was and would be higher in Liaoning Province than in Heilongjiang Province; in 2041-2100, the maize temperature suitability at heading-maturing stage and in whole growth season would decrease gradually in Liaoning Province but increase gradually in east Jilin Province and Heilongjiang Province.

[Climatic potential productivity of winter wheat and summer maize in Huanghuaihai Plain in 2011-2050].

Based on the daily data under B2 climate scenario (2011-2050) and baseline climate condition (1961-1990) extracted from the regional climate model PRECIS, and by using the Agro-Ecological Zone (AEZ) model, a prediction was conducted on the possible spatiotemporal changes of the climatic potential productivity of the two crops in the Huanghuaihai Plain in 2011-2050. Under baseline climate condition, the climatic potential productivities of winter wheat and summer maize presented a regional differentiation, i.e., higher in southeast and lower in northwest regions, and higher along coast and lower in inland at the same latitudes, and fluctuated within the ranges of 3893-11000 kg x hm(-2) and 5908-12000 kg x hm(-2), respectively. Under B2 climate scenario, the climatic potential productivity of winter wheat and summer maize would have a greater inter-annual change, due to the different matching degrees of light, temperature and water during the growth periods of the crops. The climatic potential productivity of winter wheat in 2011-2030 and summer maize in 2021-2040 would have an obvious increase, with great potential for development. Under the conditions of maintaining the present production, the climatic potential productivity of winter wheat in 2011-2050 would present an overall regional differentiation of reverse change in southeast and northwest regions and the same change in coastal and inland areas, whereas the climatic potential productivity of summer maize in 2011-2050 would have little regional differentiation.

[Effect of Matrine on cell cycle and human telomerase reverse transcriptase of human salivary adenoid cystic carcinoma].

OBJECTIVE: To investigate the effect of the traditional Chinese medicine Matrine on cell cycle and human telomerase reverse transcriptase (hTERT) of human ACC-M cell lines. METHODS: Different concentrations of Matrine were used in the medium of ACC-M cells. Change of cell cycle were detected by flow cytometry after ACC-M cell were cultivated with different concentrations Matrine (0.25, 0.50, 0.75, 1.00 mg x mL(-1)). Expression of hTERT was investigated by reverse transcription-polymerase chain reaction (RT-PCR) and indirect immunofluorescene and flow cytometry quantitative analysis. RESULTS: Matrine caused obviously the GdG1 phase block and inhibited proliferation of ACC-M cells. At same time, this effect was positive correlation to Matrine concentration and treat time. Matrine can inhibit the expression of hTERT mRNA and protein. CONCLUSION: Matrine can obviously inhibit cell cycle and down-regulate expression of hTERT. Inhibition of cell cycle is possible correlation with down-regulation expression of hTERT.

[Change trends of China agricultural thermal resources under climate change and related adaptation countermeasures].

Based on the 2011-2050 A2 climate scenario derived from the regional climate model PRECIS and the daily data of 1961-1990 baseline climate condition, this paper analyzed the possible changes of the agricultural thermal resources in China from 2011 to 2050. Comparing with the baseline climate condition in 1961-1990, the average frost-free periods in most parts of China in 2011-2050 under A2 climate scenario would have an obvious extension, mainly manifested in the advance of last frost date and the postpone of first frost date. The days with the daily average temperature stably passing 0 degrees C would also prolong significantly, and extend from 1 day to 14 days in most parts of the country. Especially from 2041 to 2050, the days with the daily average temperature stably passing 0 degrees C in most regions of Qinghai-Tibet Plateau, middle and lower reaches of Yangtze River, and western and southwestern regions of Gansu and Xinjiang could be extended by 49 days. The > or = 0 degrees C accumulated temperatures in most parts of the country would have increasing trends. In order to meet the future change trend of our agricultural thermal resources and to realize the sustainable development of agriculture in China, some countermeasures should be formulated, e.g., further adjusting agricultural cropping system, optimizing agricultural production distribution, developing biotechnology, and so on.

[The application of three-dimensional reconstruction technique of 64-slices spiral CT in locating of embedded teeth in jaws].

OBJECTIVE: To study the allocation of embedded teeth in jaws using the three-dimensional reconstruction technique of 64-slices spiral CT. METHODS: 27 cases were examined by helical scanning of axial view volume scan CT. The exact localization of the embedded teeth in jaws was acquired by using volume rendering (VR), maximum intensity projection (MIP), multiplanar reformation (MPR) and curve plane reconstruction (CPR). RESULTS: The localization, morphous, size, erupted orientation and relationship between surrounding tissues of the 41 embedded teeth in 27 patients were displayed by effectually using the images of VR, MIP, MPR and CPR. The election of orthodontic treatment or surgical intervention was decided by using 64-slices spiral CT. CONCLUSION: The exact data and objective evidence of the treatment plan could be provided by 64-slices spiral CT which will have important clinical application.

[Effect and mechanism of matrine on adhesion and invasion of salivary gland adenoid cystic carcinoma cells in vitro].

PURPOSE: To investigate the effect and mechanism of matrine on adhesion and invasion of human adenoid cystic carcinoma ACC-M cells in vitro. METHODS: MTT assay was used to examine the effect of matrine on proliferation of ACC-M cells treated after 1 day to 3 days. Byden chamber assay was performed to detect the effect of matrine on invasion capacity of the cells; Effect on adhesion potential of ACC-M cells was tested by cell matrigel adhesion assay. Mechanism of inhibitory adhesion and invasion was investigated by expression of E-cad protein. The results was analyzed by SPSS11.0 software package. RESULTS: Matrine could inhibit the proliferation of ACC-M cell lines with apparent dose-dependent and time-dependent effect. Matrine significantly inhibited adhesion and invasion capacity of ACC-M cell lines in vitro with concentration increasing. The expression level of E-cad was significantly increased compared with the untreated group in ACC-M cell lines. CONCLUSIONS: Matrine can inhibit the adhesion and invasion capacity of ACC-M cell lines in vitro. Mechanism of the inhibition effect may be related to over expression of E-cad protein.

[Simulation of carbon stocks of forest ecosystems in Northeast China from 1981 to 2002].

Based on the forest carbon budget model for China FORCCHN, which had been improved through adding variables and modules of precipitation (rainfall and snowfall) intercepted by tree crown and of understory and litter, the spatiotemporal distribution pattern of carbon stocks of forest ecosystems in Northeast China from 1981 to 2002 were simulated. The results showed that from 1981 to 2002, the forest ecosystems in Northeast China played a role of carbon sink, and the total carbon stock was about 12.37 Pg C x a(-1), of which, the stock of vegetation and soil was 4.01 Pg C x a(-1) and 8.36 Pg C x a(-1), respectively. During the study period, the carbon stock of both vegetation and soil all had an increasing trend, and the increase of air temperature contributed more than the change of precipitation. Spatially, the carbon density of vegetation had the characteristics of high in southeast part and low in northwest part, with an average of 10.45 kg C x m(-2). Most of the forest ecosystems in Northeast China had a higher soil carbon density, with a mean value of 21.78 kg C x m(-2) and the maximum in part regions of Daxing'anling, Xiaoxing'anling, and Changbai mountains. The forest area in Northeast China accounted for 31.4% of that in the whole country, possessing an important position in China forest carbon pool. The carbon stock of vegetation and soil in the forests of Northeast China occupied 74.23% and 63.88%, and the carbon density of vegetation and soil was 2.70 and 1.22 times of that in the forests of the whole country, respectively.