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Biomedical subjects

Xin Li

Publications and source records attributed to Xin Li.

At least 289 records · Page 16Linked to original sources
PubMed2003

Molecular marker analysis and genetic basis for sterility of typical indica/japonica hybrids.

To explore the genes differentiated between typical indica and japonica varieties, two typical indica/japonica varieties, Balilla (japonica) and Nantehao (NTH, indica), were selected to construct genetic populations based on the widely surveying for spikelet and pollen fertility of 90 indica/japonica F1 hybrids, which also were used as the wide compatability testers. In order to analyze the genes (QTLs) related to spikelet and pollen fertility, two reciprocal backcross populations Balilla/NTH//Balilla and Balilla/NTH//NTH were constructed and the spikelet and pollen fertility of each individuals were assessed. In both populations, two traits all appeared distorted normal distribution, but in the first population, they forwarded to low-level fertility type, the later population, forwarded to high-level fertility type relatively. The results indicated that both of male and female gametophytes of Balilla/NTH hybrids were partial sterile. Then we analyzed the SSR marker genotype of each individuals of Balilla/NTH//Balilla population containing 142 individuals, and constructed a SSR linkage map, in which, there were 108 information markers distributing on all 12 chromosomes equably, average marker distance was about 11.9 cM. Therefore the linkage map was qualified for QTL analysis. Two methods were employed to conduct QTLs analysis, i.e., single marker analysis and interval mapping. According to single marker analysis, 17 and 12 markers were found significantly responsible for spikelet and pollen fertility, respectively. And further study by means of MAPMAKER/QTL software, for spikelet fertility trait, two QTLs were detected, qSPTF1 on chromosome 1 and qSPTF6 on chromosome 6, and their additive effect were 13.501 and -16.414, respectively. According to previous studies, qSPTF6 was deduced to be the same locus as S-5. For pollen fertility, qPLLN7 on chromosome 7 and qPLLN9 on chromosome 9 were detected, and their additive effects were -12.003 and -11.012, respectively. Because the QTLs detected cannot explain completely the total variance of mapping population, other genetic factors must be existed to be responsible for spikelet and pollen partial sterility. Hence we let two random markers as putative covariates, and divide the 142 individuals into four groups according to the two marker genotypes, then the average values of spikelet and pollen fertility of each groups were calculated for two-way ANOVA (analysis of variance). The results indicated that there existed strong interaction for both spikelet fertility and pollen fertility. At a significance level of 0.005, there over 61 and 51 pairs loci interactions detected playing an important role in spikelet and pollen sterility expression, respectively. These results indicated that epistasis also was one of major genetic components controlling indica/japonica hybrid sterility.

Analysis of Variance↗
PubMed2003

[Analysis on the trend of severe acute respiratory syndrome epidemic in Inner Mongolian Autonomous Region].

OBJECTIVE: To analyse the severe acute respiratory syndrome (SARS) epidemics in Inner Mongolian Autonomous Region and to provide scientific basis for prevention and control strategies against it. METHODS: Data from legal communicable diseases surveillance reporting system was analyzed epidemiologically. RESULTS: The first SARS case was reported in Inner Mongolian Autonomous Region on March 27, 2003. Up to May 20, there were 446 cumulative SARS cases in the whole region (with 287 confirmed cases and 159 suspected cases) and 61 cumulative recovered cases had been discharged from the hospitals (56 confirmed cases and 5 suspected cases). Another 131 cases were excluded the original diagnoses of SARS including 10 confirmed cases and 121 suspected cases. 25 confirmed cases died with a mortality rate of 8.7%. Cumulatively, the number of reported cases were distributed in 30 counties in 9 prefectures. Statistical analysis on time sequence of the occurrence of cases showed that majority (67.7% of the total) of the cases concentrated in between April 13 and April 29. The number of cases had started to decrease since April 24 with an average of 5.3 cases per day between May 3 and May 8 and an average of 0.3 cases per day between May 9 and today. CONCLUSIONS: SARS epidemics in our region could be divided into three phases. The first phase fell in between March 18 and April 15 with the first case being imported, the number of cases rose sharply, covering 14 counties in 6 prefectures, having a feature of family clustering. The second phase was from April 16 to April 28, with the appearance of secondary infection, having sharp rise of the cases and spreading to 24 counties in 10 prefectures. One of the major features was that hospitals had become the important sources of secondary infection. Finally, the third phase was between April 29 and May 20, with small wave crests of cases, spreading to 38 counties in 10 prefectures with a high proportion of cases with no history of direct contact with diagnosed SARS patients. Thus, no obvious transmission chain was noticed at this phase.

Adolescent↗
PubMed2003

[Study on etiology and pathology of severe acute respiratory syndrome].

OBJECTIVE: To investigate the clinicopathologic characteristics of severe acute respiratory syndrome (SARS). METHODS: Three autopsy cases were studied retrospectively. Routine HE stain was used to study all the cases. Part of the lung tissue specimens were studied further with Macchiavello's stain, viral inclusion body stain, reticulin and PAS stains, immunohistochemistry, thin sections with staining, light microscopy and transmission electronic microscope investigation. RESULTS: The earliest symptom of all 3 cases was hyperpyrexia and followed by progressive dyspnea and appearance of lung field shadows in X rays findings. Pulmonary lesions included: bilateral and extensive consolidation, localized hemorrhage and necrosis, desquamative alveolitis and bronchitis, alveolar proliferation and desquamation, accumulation of protein exudates, mononuclear cells, lymphocytes, and plasma cells as well as hyaline membrane formation in alveoli and viral inclusion bodies were seen in the alveolus epithelial cells. The exudated organization tended to become glomeruloid organizing pneumonitis in a few avaoli. Lesions of the immune organs included: large patchy necrosis in the spleens and localized necrosis in the lymph nodes were seen. Bone marrow became restrained. There were lesions of systemic small vasculitis including edema of the perivascular tissue and vascular wall of the small veins with localized fibrinoid necrosis distributing in the heart, lungs, kidneys, adrenal glands and the striated muscles accompanying with mononuclear cells and lymphocytes infiltration. Thrombosis was seen in part of the small veins. In addition, there were also the systemic poisonous changes including: degeneration and necrosis of the parenchyma cells in lungs, liver, kidneys, heart and adrenals. Electronic microscopy demonstrated clusters of virus particles seen in the lung tissue. CONCLUSION: SARS is a systemic disease. Lungs, immune system and systemic small vessels are the main target organs attacked by the virus. Extensive consolidation of lungs, formation of hyaline membrane to a large extent, respiratory distress and decrease of immune function are the main causes of death.

Adult↗
PubMed2003

[Fractal properties of the spatial pattern of rare and endangered plant populations in Houhe Nature Reserve in Hubei: Box-counting dimension].

The fractal properties of the spatial distribution pattern of 4 dominant plant populations and 7 rare and endangered plant populations were reflected through the box-counting dimensions. The results showed that the box-counting dimensions of 4 dominant populations ranged between 1.346 and 1.414, and occupied relatively larger ecological spaces in the community. Camellia cuspidata population occupied the largest ecological space because of its biggest box-counting dimensions. However, most of other populations occupied relatively smaller spaces due to their smaller values of the box-counting dimensions. The box-counting dimensions of 7 rare and endangered populations were smaller than 1 except Dipteronia sinensis population. The inflexion scales of 11 populations covered the range from 5 m to 12.5 m. According to the self-similarity of the fractal, the distribution pattern types under certain scales larger than the inflexion scale could be inferred as similar, and the results partly proved the ideas. The populations of Disopyros lotus, Pterostyrax psilophyllus, Davidia involucrata, Tetracentron sinense and Aesculus wilsonii were changed at the inflexion scale, and other 6 populations had the same distribution pattern types despite of the scale changed.

Conservation of Natural Resources↗
PubMed2003

[The research on IR and TEM of polybutylcyanoacrylate nanoparticles].

Through latex polymerization with stabilizer (Dextran, low fraction), we prepared polybutylcyanoacrylate nanoparticles with a size of approximately 200 nm. The nanoparticle diameter decreases with decreasing stabilizer concentration. Using TEM and IR we studied the combination state and the mechanism between polybutylcyanoacrylate and Dextran. It was shown that each Dextran molecule could therefore contain several cyanoacrylate polymer moieties covalently linked via any of the available Dextran hydroxyl groups. Anchoring of the cyanoacrylate groups within the nanoparticle matrix would therefore result in an irreversible attachment between the Dextran and the nanoparticle. In this way, Dextran could be incorporated throughout the particle matrix as well as on the surface, producing the biodegradable particle. The results have been interpreted by reference to the accepted theories of steric stabilization and dispersion polymerization, and a model is proposed for the nanoparticle formation in the presence of Dextran.

Biocompatible Materials↗
PubMed2003

[Cyclosporine A and mycophenolate mofetile as prophylactics for GVHD in a murine model of H-2 haploidentical nonmyeloablative bone marrow transplantation].

In order to research the prophylactic effect of cyclosporine A (CSA) and mycophenolate mofetile (MMF) on GVHD in mice with H-2 haploidentical nonmyeloablative bone marrow transplantation, a murine model was established by using of C57BL/6J mouse as donor and (C57BL/6J x BALB/C) F(1) mouse as the recipient. The recipient mice were given CSA + MTX or CSA + MMF for prophylaxis of acute GVHD (aGVHD). The survival rate, hematopoietic recovery, and morbidity and mortality of aGVHD were observed for 50 days after transplantation. The results showed that typical aGVHD developed in the transplanted mice without prophylactic treatment during 22 to 25 days after transplantation. The morbidity of aGVHD was 75% (15/20), 40% (8/20) and 30% (6/20) and mortality was 100% (15/15), 62.5% (5/8) and 50% (3/6) respectively in unprophylactic group (control), CSA + MTX and CSA + MMF groups. In conclusion, CSA and MTX reduce the morbidity and mortality of aGVHD in mice with haploidentical nonmyeloablative bone marrow transplantation, and the effect of CSA + MMF is better than that of CSA + MTX.

Animals↗
PubMed2003

[Structures and spatial distribution patterns of dominant populations in Sycopsis sinensis community in Houhe Nature Reserve].

Based on the investigation data of 2 quadrats (1,600 m2 and 2,400 m2) in Houhe Nature Reserve, tree size class method was applied to analyze the structures of the dominant populations, and t-test of v/m ratio, mean crowing index, negative binomial parameter, patchiness index and Morisita index were applied to analyze the spatial distribution patterns of two dominant populations. The clumping degrees were also evaluated according to their size classes in different quadrats. The results showed that Sycopsis sinensis population was a declining population, dominated by IV trees and difficult to regenerate. In the population, the individual percentage of IV trees accounted for 79.4% in Q1 and 87.4% in Q2, and those of I trees and II trees were few. However, the population of Cyclobalanopsis axyodon was an growing one, and the individual percentages declined with the increasing size classes. The spatial distribution patterns of the two dominant populations distributed in clumps, but the clumping degrees existed diversity. With the increase of the size classes, the clumping degree of the population of Sycopsis sinensis intensified from random to clumping distribution, while that of the population of Cyclobalanopsis axyodon weakened from clumping to random distribution.

Conservation of Natural Resources↗
PubMed2003

The role of donor hepatocytes and/or splenocytes pre-injection in reducing islet xenotransplantation rejection.

OBJECTIVE: To observe the effect of tail vein injection with donor hepatocyte and/or splenocyte on islets xenotransplantation rejection. METHODS: New-born male pigs and BALB/C mice were selected as donors and recipients respectively. Islets xenotransplantation was performed in recipients just after the third time of tail vein injection with donor hepatocytes and/or splenocytes. Macrophage phagocytosis, NK killing activity, T lymphocyte transforming function of spleen cells, antibody forming function of B lymphocytes, and T lymphocyte subsets were taken to monitor transplantation rejection. The effects of this kind of transplantation were indicated as variation of blood glucose and survival days of recipients. RESULTS: Streptozotocin (STZ) succeeded in inducing diabetes mellitus models of mice. Pre-injection of donor hepatocytes, and splenocytes or their mixture via tail vein was effective in preventing donor islets transplantation from rejection, which was demonstrated by the mentioned immunological marks. And each group of transplantation could decrease the blood glucose of recipients and prolong the survival days. Pre-injection of mixture of donor hepatocytes and splenocytes was more effective in preventing rejection than pre-injection of donor hepatocytes or splenocytes separately. CONCLUSION: We propose that pre-injection of donor hepatocytes, splenocytes separately or their mixture before donor islets transplantation is a good way to prevent rejection.

Animals↗
PubMed2003

[Detection of severe acute respiratory syndrome (SARS)-associated coronavirus RNA in autopsy tissues with in situ hybridization].

OBJECTIVE: To explore the distribution of severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) in SARS autopsy tissues at the molecular level. METHODS: In situ hybridization was used to detect the expression and location of SARS-CoV RNA polymerase gene in autopsy tissues from SARS-Cov-infected subjects, including the lung, spleen, lymph nodes, pituitary, pancreas, parathyroid, adrenal glands, gastrointestinal tract, skin, brain, liver, kidney, blood vessels, striated muscles of the limbs, bone marrow, heart, ovary, uterus and testicles. RESULT: SARS-CoV RNA was detected in the cytoplasm of the alveolar epithelia, infiltrating mononuclear phagocytes in the lungs, serous gland epithelium of the trachea/bronchus, monocytes in the spleen and lymph nodes, acinar cells in the pancreas, acidophilic cells in the parathyroid and pituitary, adrenal cortical cells, epithelia of the alimentary tracts, gastric parietal cells, sweat gland cells, brain neurons, hepatocytes near the central vein, epithelia of the distal renal tubules, bone marrow promyelocytes, and endothelia of the small veins. CONCLUSIONS: SARS-CoV invades various organs of the body and distributes in a similar fashion to CD13, the receptor of human coronavirus 229E. The detection of SARS-CoV in the sweat glands, alimentary tracts and epithelia of the distal convoluted tubules of the kidney may help identify the transmission routes of SARS-CoV.

Autopsy↗
PubMed2003

[Expression of the monoclonal antibody against nucleocapsid antigen of SARS-associated coronavirus in autopsy tissues from SARS patients].

OBJECTIVE: To investigate the presence and distribution of severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) in autopsy tissues obtained from patients died of SARS. METHODS: Immunohistochemical technique was applied in 4 fatal SARS cases to examine the autopsy tissues including the lungs, spleen, lymph nodes, brain, pituitary, heart, liver, kidney, pancreas, trachea, esophagus, gastrointestinal tract, adrenal glands, parathyroids, skin and bone marrow. RESULTS: Immunohistochemistry identified positive monoclonal antibody against SARS-CoV nuceeocapsid (N) protein in the alveolar epithelium and the infiltrating monocytes or macrophages in the lung, spleen and lymph nodes; the presence of the antibody was also detected in the serous gland epithelium of the trachea/bronchus, squamous epithelium of the esophagus, the gastric parietal cells, the epithelium of the intestinal tract, acidophilic cells in the parathyroids and pituitary, acinus cells in the pancreas, adrenal cortical cells, sweat gland cells, small vessel endothelium, bone marrow promyelocytes, epithelial cells of the distal convoluted tubule of the kidney, brain neurons, and the hepatocytes near the central vein. CONCLUSIONS: A variety of organs and tissues can be infected by SARS-CoV, and the positive expression of SARS-CoV N protein in the epithelial cells of the gastrointestinal tract, the distal convoluted tubule of the kidney and the sweat gland cells is significant for studying the transmission routes of SARS.

Antibodies, Monoclonal↗
PubMed2003

[Establishment of protein spectrum of nasopharyngeal carcinoma cell line HNE-1 by two-dimensional polyacrylamide gel electrophoresis].

OBJECTIVE: To establish optimized two-dimensional (2-D) polyacrylamide gel electrophoresis (PAGE) for displaying the full-scale protein expression spectrum of nasopharyngeal carcinoma (NPC) cell line HNE-1, which can be instrumental for proteomic study of NPC. METHODS: Large-scale HNE-1 cell culture was carried out from which the total protein was extracted with optimized method and separated by isoelectric focusing with linear and non-linear immobilized pH gradient (IPG) strips between different pH ranges followed by vertical SDS-PAGE. The 2-D maps of the proteins of HNE-1 cell line were then established. RESULTS: 2-D maps of the total protein of HNE-1 cell line were effectively displayed on IPG strips of different pH ranges and with optimized 2-D electrophoresis. CONCLUSION: With IPG strips with overlapping pH ranges, improvement of the protein separation can be achieved in 2-D electrophoresis.

Cell Line, Tumor↗
PubMed2003

[Mapping quantitative trait loci associated with rice grain shape based on an indica/japonica backcross population].

Appearance of rice grain represents a major character of rice quality in many rice-producing areas of the world, especially in hybrid rice production in China. In this study, we conducted a molecular marker-based genetic analysis of the traits that are determinants of the appearance quality of rice grains, including grain length, grain width and grain shape (measured as grain length to grain width ratio). Two typical indica/japonica varieties Balilla and Nantehao(NTH) were selected to construct Balilla/NTH//Balilla backcross population containing 142 individuals. In the population, grain length, grain width and grain shape all conform to the normal distribution with certain transgressive segregation. It can be deduced that all of three traits were controlled by some quantitative trait loci (QTLs). In order to explore the QTLs effect, number and location, a linkage map consisting of 108 SSR markers based on the backcross population was constructed, and QTLs mapping was carried out for grain length, grain width and grain shape. A QTL, qGL-12, was detected for grain length at the interval RM101-RM270 on chromosome 12, its additive effect was 0.26 mm, and can explain 16.7% genetic variation. As for grain width trait, two QTLs were found, qGW-2 located at RM154-RM211 interval on chromosome 2, and qGW-3 at interval RM257-RM175 on chromosome 3, accounting for 11.5% and 16.6% genetic variation, respectively. The alleles at qGW-2 and qGW-3 from parent Balilla can increase grain width by 0.10 mm and 0.12 mm. For grain shape, 3 QTLs, qLW-2, qLW-6 and qLW-7 were found, located on chromosome 2, 6, and 7, respectively. qLW-2 and qLW-7 had positive effect, and they can explain 12.7% and 18.3% genetic variation, while qLW-6 had negative effect and contributed 11.5% genetic variation to the backcross population. The prospects of application of linkage relationship between SSR marker and QTLs in marker based selection (MAS) in rice breeding, and the improvement of grain shape and rice appearance quality were discussed.

Chromosome Mapping↗
PubMed2003

[Pharmacokinetics of genistein in beagle dogs].

AIM: To study the pharmacokinetics of genistein in Beagle dogs. METHODS: Genistein, suspended in 0.5% CMC-Na solution, was orally administered to Beagle dogs at the dose of 5.34 mg.kg-1. At various time intervals, 1.5 mL of blood was drawn from the vein of dogs in their front legs. At the same time, urine and feces were collected. After the collection, the feces were homogenized with physiological saline (to 1 g feces, 10 mL physiological saline were added). The genistein in plasma, urine and homogenized feces was extracted twice by vortexing with 2.0 mL mixture of methyl tert-butyl ether and pentane (8:2). The organic phase was transferred into tubes and evaporated in ventilation cabinet. The residue was dissolved in 50 microL of methanol and 20 microL of the solution was drawn and detected by high-performance liquid chromatography. The pharmacokinetic parameter was calculated by 3P97 software. RESULTS: The plasma concentration-time curve was fitted to a one-open-compartment model. The peak time was 0.29 h, and the elimination half-life was 0.52 h. After genistein was administered, 10.79% of genistein were excreted from urine and 21.55% from feces within 24 h. It was also found that 13.00% genistein were excreted from urine and 52.46% from feces within 60 h. CONCLUSION: It showed that the speed of absorption and elimination of genistein was high in Beagle dog, and genistein was mainly excreted in the form of parent compound in urine and feces.

Animals↗
PubMed2003

[Measurements of atmospheric boundary layer O3, NOx and CO in summer with Beijing 325 m meteorological tower].

Based on the Beijing 325 m meteorological tower, O3, NOx and CO concentrations and meteorological parameters in urban atmospheric boundary layer were measured in July 2002. The variations of O3 concentration were remarkably different among the five levels. Contrasted with the higher levels, the daily variations were clear and the difference values between day and night were large in the lower levels. It was also found that the photochemistry reaction was an important source in boundary layer in daytime and precipitation process could arouse marked change of O3 concentration.

Air Pollutants↗
PubMed2003

[The expression of activin A and transforming growth factor-beta 1 during rabbit mandibual distraction osteogenesis].

OBJECTIVE: To examine the expression of activin A (ACT A) and transforming growth factor-beta 1 (TGF-beta 1) during mandibular lengthening and elucidate the difference between the role of ACT A and TGF-beta 1 during mandibular distraction osteogenesis. METHOD: Skeletally mature white new zealand rabbits were established right mandibular distraction osteogenesis model. The regenerating tissue of animals' lengthened mandibes were harvested at different time points to have immunohistochemistric research of ACT A, TGF-beta 1 protein and analysis ACT A, TGF-beta 1 mRNA by using RT-PCR semiquantitative mean. RESULTS: AT the end of latency period day, positive stain of ACT A were found in the osteoblasts while positive stain of TGF-beta 1 was found in mesenchymal cells. At the end of distraction phase, fibrosis tissue had no stain of ACT A, but had strong stain of TGF-beta 1. At the period of fixation days of 20 days, both cytoplasm of osteoblasts and extracellular matrix in primary mineralization front were strongly stained of ACT A. The osteoblasts, osteoid and osteocytes in peripheral new bone zone were moderately stained of ACT A. TGF-beta 1 had strongly positive stained in fibrosis zone and weekly positive stained in primary mineralization front and peripheral new bone zone. There were also broad activin A stains in cytoplasm of osteoblasts, osteoid and cytoplasm of ACT A, TGF-beta 1 in osteocytes after distraction for 30 days. Activin A mRNA began to express at the end of latency period. Expression for activin A mRNA increased gradually along with the beginning of distraction and at the peak in distraction of 10 days and 20 days, while TGF beta 1 mRNA increased at the peak at the end of latency period. CONCLUSION: ACT A and TGF beta 1 have different role during rabbit mandibular distraction osteogenesis.

Activins↗