Biomedical subjects
Publications and source records attributed to Li Li.
Genetic characterization of a human cerebrospinal fluid West Nile virus isolate from Beaumont, Texas, revealed several nucleotide changes and amino acid substitutions that differentiated it from all other North American strains isolated to date, suggesting that isolates from the Texas Gulf Coast may form a unique genetic group among North American strains.
Two isolates of a virus of the genus Orthobunyavirus (family Bunyaviridae) were obtained from hemorrhagic fever cases during a large disease outbreak in East Africa in 1997 and 1998. Sequence analysis of regions of the three genomic RNA segments of the virus (provisionally referred to as Garissa virus) suggested that it was a genetic reassortant virus with S and L segments derived from Bunyamwera virus but an M segment from an unidentified virus of the genus Orthobunyavirus. While high genetic diversity (52%) was revealed by analysis of virus M segment nucleotide sequences obtained from 21 members of the genus Orthobunyavirus, the Garissa and Ngari virus M segments were almost identical. Surprisingly, the Ngari virus L and S segments showed high sequence identity with those of Bunyamwera virus, showing that Garissa virus is an isolate of Ngari virus, which in turn is a Bunyamwera virus reassortant. Ngari virus should be considered when investigating hemorrhagic fever outbreaks throughout sub-Saharan Africa.
China is facing a rapid upsurge in cases of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) infection due to large numbers of paid blood donors (PBD), injection drug users (IDU), and sexual partners of infected individuals. In this report, a total of 236 HIV-1-positive blood samples were collected from PBD, IDU, and their sexual partners in the most severely affected provinces, such as Henan, Yunnan, Guangxi, and Xinjiang. PCR was used to amplify the p17 region of gag and the C2-V3 region of env of HIV-1 and the 5' noncoding region and a region of E1/E2 of HCV. Genetic characterization of viral sequences indicated that there are two major epidemics of HIV-1 and multiple HCV epidemics in China. The PBD and transfusion recipients in Henan harbored HIV-1 subtype B', which is similar to the virus found in Thailand, and HCV genotypes 1b and 2a, whereas the IDU in Yunnan, Guangxi, and Xinjiang carried HIV-1 circulating recombinant forms 07 and 08, which resemble those in India, and HCV genotypes 1b, 3a, and 3b. Our findings show that the epidemics of HIV-1 and HCV infection in China are the consequences of multiple introductions. The distinct distribution patterns of both the HIV-1 and HCV genotypes in the different high-risk groups are tightly linked to the mode of transmission rather than geographic proximity. These findings provide information relevant to antiviral therapy and vaccine development in China and should assist public health workers in implementing measures to reduce the further dissemination of these viruses in the world's most populous nation.
In several crop species within the Triticeae tribe of the grass family Poaceae, single major aluminum (Al) tolerance genes have been identified that effectively mitigate Al toxicity, a major abiotic constraint to crop production on acidic soils. However, the trait is quantitatively inherited in species within other tribes, and the possible ancestral relationships between major Al tolerance genes and QTL in the grasses remain unresolved. To help establish these relationships, we conducted a molecular genetic analysis of Al tolerance in sorghum and integrated our findings with those from previous studies performed in crop species belonging to different grass tribes. A single locus, AltSB, was found to control Al tolerance in two highly Al tolerant sorghum cultivars. Significant macrosynteny between sorghum and the Triticeae was observed for molecular markers closely linked to putatively orthologous Al tolerance loci present in the group 4 chromosomes of wheat, barley, and rye. However, AltSB was not located within the homeologous region of sorghum but rather mapped near the end of sorghum chromosome 3. Thus, AltSB not only is the first major Al tolerance gene mapped in a grass species that does not belong to the Triticeae, but also appears to be different from the major Al tolerance locus in the Triticeae. Intertribe map comparisons suggest that a major Al tolerance QTL on rice chromosome 1 is likely to be orthologous to AltSB, whereas another rice QTL on chromosome 3 is likely to correspond to the Triticeae group 4 Al tolerance locus. Therefore, this study demonstrates a clear evolutionary link between genes and QTL encoding the same trait in distantly related species within a single plant family.
This paper discusses propagation of perturbations along traffic flow modeled by a modified second-order macroscopic model through the wavefront expansion technique. The coefficients in this expansion satisfy a sequence of transport equations that can be solved analytically. One of these analytic solutions yields information about wavefront shock. Numerical simulations based on a Pade approximation of this expansion were done at the end of this paper and results showed that propagation of perturbations at traffic flow speed conforms to the theoretical analysis results.
Human embryonic stem cells (hESCs) are envisioned to be a major source for cell-based therapies. Efforts to overcome rejection of hESCs include nuclear transfer and collection of hESC banks representing the broadest diversity of major histocompatability complex (MHC) polymorphorisms. Surprisingly, immune responses to hESCs have yet to be experimentally evaluated. Here, injection of hESCs into immune-competent mice was unable to induce an immune response. Undifferentiated and differentiated hESCs failed to stimulate proliferation of alloreactive primary human T cells and inhibited third-party allogeneic dendritic cell-mediated T-cell proliferation via cellular mechanisms independent of secreted factors. Upon secondary rechallenge, T cells cocultured with hESCs were still responsive to allogeneic stimulators but failed to proliferate upon re-exposure to hESCs. Our study demonstrates that hESCs possess unique immune-privileged characteristics and provides an unprecedented opportunity to further investigate the mechanisms of immune response to transplantation of hESCs that may avoid immune-mediated rejection.
To elucidate the genetic alterations that are specific to Thorotrast-induced liver cancers and their possible roles in tumorigenesis, we analyzed loss of heterozygosity (LOH) at 37 loci. Our previous study of liver cancers that were not associated with Thorotrast found LOH at 9 of these loci to be characteristic of intrahepatic cholangiocarcinoma (ICC), at 19 to be characteristic of hepatocellular carcinoma (HCC), and at 9 to be common to both ICC and HCC. LOH analysis was also performed in tissues of cholangiolocellular carcinoma, which is thought to originate from a common stem cell progenitor of hepatocytes and bile duct epithelial cells. We found frequent LOH at D4S1538, D16S2624 and D17S1303 to be common to all the subtypes of liver cancers, independent of the specific carcinogenic agent. In contrast, LOH at D4S1652 generally was not observed in Thorotrast-induced ICC. LOH analysis revealed that Thorotrast-induced ICC shares some LOH features with both ICC and HCC that were not induced by Thorotrast; however, it is more similar to ICC than to HCC in terms of genetic changes. This study could narrow down the crucial chromosomal loci whose deletions are relevant to hepatobiliary carcinogenesis irrespective of the carcinogenic agent. The study of LOH at loci other the those crucial ones may help us understand how the phenotype of liver cancers is determined.
To determine whether exposure to radiofrequency (RF) radiation can induce DNA damage or apoptosis, Molt-4 T lymphoblastoid cells were exposed with RF fields at frequencies and modulations of the type used by wireless communication devices. Four types of frequency/modulation forms were studied: 847.74 MHz code-division multiple-access (CDMA), 835.62 MHz frequency-division multiple-access (FDMA), 813.56 MHz iDEN(R) (iDEN), and 836.55 MHz time-division multiple-access (TDMA). Exponentially growing cells were exposed to RF radiation for periods up to 24 h using a radial transmission line (RTL) exposure system. The specific absorption rates used were 3.2 W/kg for CDMA and FDMA, 2.4 or 24 mW/kg for iDEN, and 2.6 or 26 mW/kg for TDMA. The temperature in the RTLs was maintained at 37 degrees C +/- 0.3 degrees C. DNA damage was measured using the single-cell gel electrophoresis assay. The annexin V affinity assay was used to detect apoptosis. No statistically significant difference in the level of DNA damage or apoptosis was observed between sham-treated cells and cells exposed to RF radiation for any frequency, modulation or exposure time. Our results show that exposure of Molt-4 cells to CDMA, FDMA, iDEN or TDMA modulated RF radiation does not induce alterations in level of DNA damage or induce apoptosis.
Human microsporidiosis has been described most commonly in patients with acquired immunodeficiency syndrome and only rarely in those with other forms of immunosuppression. Only 11 cases of microsporidiosis have been reported previously in solid transplant recipients. To our knowledge, this is the first report to describe a case of microsporidiosis in a pancreas/kidney transplant recipient in whom multi-organ system dissemination was observed. This infection was not detected until postmortem examination of stained tissue sections revealed microsporidian spores that were identified as Encephalitozoon species by transmission electron microscopy. It is suspected that leakage from the duodenal anastomosis to the bladder may have contributed to the dissemination of this infection.
OBJECTIVE: To optimize the extraction process of Radix Ginseng Rubra. METHODS: The orthogonal test design was used to test the three main factors of circulatory percolation process, including particle size of herb (A), velocity of percolation(B) and time for extraction (C), and the synthetic score basing on obtained rate of ginsenosides Rg1, Re and extraction efficiency was used as guide. RESULTS: The optimum process conditions relevant to the three main factors were as follows. The coarse powder was percolated at a velocity of 0.2 L/min for six hours. CONCLUSION: The circulatory percolation process is better than the reflux process and maceration process for extraction of Radix Ginseng Rubra.
OBJECTIVE: To compare the clinical outcomes between HLA allele matched (HLA-M) and 1 approximately 2 alleles disparity mismatched (HLA-mis) unrelated allogeneic bone marrow transplantation (URD-BMT). METHODS: Thirty-nine patients received HLA-M and 21 received HLA-mis URD-BMT for the treatment of acute leukemia, chronic myeloid leukemia in chronic phase (CP) and myelodysplastic syndromes (MDS) in our hospital between November 1998 and December 2002. Conditioning regimen was Bu 16 mg/kg plus CTX 120 mg/kg, and mycophenolate mofetil (MMF), CsA and MTX were given to prevent aGVHD. RESULTS: Thirty-eight of the HLA-M group and 18 of the HLA-mis group were engrafted successfully. The median follow-up duration was 11 (2.5 - 52.0) months for HLA-M group and 9 (2 - 46) months for HLA-mis group. The 3-year probabilities of disease-free survival (DFS) for HLA-M and HLA-mis group were (79.2 +/- 7.1)% and (45.8 +/- 15.5)%, respectively (P < 0.05). Grade II - IV aGVHD occurred in 10 (26.3%) patients in HLA-M group and 6 (33.3%) in HLA-mis group, respectively (P > 0.05). CONCLUSION: URD-BMT is an effective modality for the treatment of leukemia and MDS. The outcome after URD-BMT can be optimized by matching the HLA-A, B and DR alleles between the donor and recipient.
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BACKGROUND & OBJECTIVE: Early detection of breast cancer is crucial to improve the therapeutic effect and to increase the survival rate. However, it is difficult because breast cancer in early stage was usually occult, impalpable, and could not be detected by laboratory test. This study was designed to compare the effectiveness of three methods for diagnosis of non-palpable breast cancer. METHODS: Twenty-four patients with impalpable breast mass suggested by computer-aided stereotactic mammography were performed with three kinds of methods, including fine-needle aspiration cytology (FNAC), large-core needle biopsy (LCNB), and frozen section biopsy (FSB) with focus staining. The results were compared with postoperative pathology. RESULTS: Compared with postoperative pathology results, the diagnostic consistent rates of FNAC, LCNB and FSB with staining focus were 75%, 92%, and 100%, respectively (P< 0.05). CONCLUSION: Frozen section with focus staining guided by computer-aided stereotactic mammography was the effective diagnostic technique for non-palpable breast cancer.
BACKGROUND: The incidence of HIV-1-related infection diseases and the mortality of AIDS have dramatically decreased since highly active antiretroviral therapy began to be used clinically in China in 1999. And we initiated a second clinical trial using a combination of Efavirenz and Indinavir to observe the effects of the immunoreaction. METHODS: Twenty patients with laboratory-confirmed chronic HIV-1 infection were recruited. Blood samples were collected initially and during the weeks after initiation of treatment. Within 48 hours of blood sampling, peripheral blood plasma and mononuclear cells were separated using routine methods. HIV-1 viral load was measured in thawed plasma samples. Within 48 hours of peripheral blood sampling, CD4(+) and CD8(+) T cell subsets were enumerated. RESULTS: The drug regimen was efficient in reducing HIV-1 plasma viral load and increasing total CD4(+) T cell counts. The percentage of CD4(+) and CD8(+) T cell subsets expressing CD38 and HLA-DR activation markers was positively correlated with plasma viral load and tended to normalize. CONCLUSIONS: The combination of Efavirenz and Indinavir was generally well tolerated and efficient at reducing HIV-1 RNA. Furthermore, the treatment improved the immunological function.
OBJECTIVE: To investigate the effects of alphavbeta6 integrin-mediated cell adhesion on cisplatin (DDP) induced apoptosis in ovarian cancer cell lines. METHODS: The expression of integrin alphavbeta6 in ovarian cancer cell lines SKOV3, AO, and 3AO was analyzed by flow cytometry, and the apoptosis induced by DDP was measured by enzyme-linked immunosorbent assay (ELISA) method and acridine orange-ethidium bromide (AO-EB) double fluorescent dye staining. RESULTS: Ovarian cancer cell lines SKOV3, AO and 3AO all expressed integrin alphavbeta6. Treated by different concentrations of DDP, SKOV3, AO and 3AO displayed significant apoptosis status compared with the control. However, after cultured in medium containing 10 micro g/ml DDP for 48 hours, SKOV3, AO and 3AO planted on fibronectin (FN)-ligand of alphavbeta6 integrin, had lower enrichment factor (EF), compared with those planted on non-integrin ligand polylisin measured by ELISA method (2.11 +/- 0.04 vs 3.51 +/- 0.03, 2.15 +/- 0.06 vs 3.55 +/- 0.04, 2.11 +/- 0.04 vs 3.66 +/- 0.04, P < 0.01). Similarly, by AO-EB double fluorescent dye staining, lower percentages of apoptosis were found in cells planted on FN (5.0 +/- 0.7)%, (5.0 +/- 0.7)%, (6.0 +/- 0.7)%, than on polylisin (28.0 +/- 0.7)%, (28.0 +/- 0.7)%, (29.0 +/- 0.7)% (P < 0.001). When cells preincubated with integrin alphavbeta6 blocking antibody were planted on FN, the percentages of apoptosis rose again, (15.0 +/- 0.7)%, (16.0 +/- 0.7)%, (15.0 +/- 0.7)% (P < 0.01). CONCLUSIONS: The de novo expression of alphavbeta6 integrin occurs in ovarian cancer cell lines SKOV3, AO, and 3AO. alphavbeta6 integrin-mediated cell adhesion to FN can inhibit the effect of cisplatin-induced apoptosis. These results suggest that inhibiting apoptotic cell adhesion may improve drug resistance in ovarian cancer cell lines.
OBJECTIVE: To investigate the relationship between susceptibility and prognosis of laryngeal cancer and genetic polymorphisms in CYP1A1 GSTM1. METHODS: The genetic polymorphisms of CYP1A1 exon-7 and GSTM1 were analyzed by polymorphism-polymerase chain reaction (PCR) technique in peripheral blood leukocytes of 89 laryngeal cancer cases and 164 non-cancer controls. RESULTS: Either in the frequency of CYP1A1 (W, MW, M) and GSTM1 negative individual of laryngeal cancer were significantly higher than that in the controls(P < 0.05). Combined genetype of CYP1A1 and GSTM1, that is CYP1A1 W/GSTM1 (-), CYP1A1 MW/GSTM1 (-), CYP1A1 M/GSTM1 (+), CYP1A1 M/GSTM1 (-) had higher risk than those combined genotypes, which ratios were 1.42 (0.62-3.22), 1.67 (0.7-4.03), 2.55 (1.0-6.54) and 4.02 (1.65-9.79), respectively. Statistic analysis suggested an interaction between smoking and CYP1A1 M/GSTM1 (-) genotypes polymorphisms which increase risk of laryngeal cancer. There was no significant difference in the frequency of CYP1A1, GSTM1 individual with the development and prognosis of laryngeal cancer. CONCLUSION: The present datas suggested that genetic polymorphisms of CYP1A1 and GSTM1 were susceptible to laryngeal cancer. Individuals with CYP1A1 M or GSTM1 (-) had increased risk of developing laryngeal cancer, but individuals with combined CYP1A1 M/GSTM1 (-) and smoking were more susceptible. Genetic polymorphisms of CYP1A1 and GSTM1 are not related with clinic process of laryngeal cancer.
BACKGROUND & OBJECTIVE: C-erbB2, C-erbB3, and C-erbB4 are numbers of epidermal growth factor family. It has been confirmed that C-erbB2 was related to ovarian carcinoma, but the relationship of C-erbB3 and C-erbB4 with ovarian carcinoma is unclear. The objective of this study was to explore the relationship of expression of C-erbB2, C-erbB3, and C-erbB4 with ovarian carcinoma. METHODS: Streptavidin-peroxidase immunohistochemistry method was used to determine the expression of C-erbB2, C-erbB3, and C-erbB4 in 49 cases of ovarian malignant neoplasms, 21 cases of ovarian benign neoplasms, and 19 cases of normal ovarian tissues (control), then the relationship of expression of C-erbB2, C-erbB3, C-erbB4 and clinicopathologic parameters in ovarian neoplasm was analyzed. RESULTS: (1) The positive expression rates of C-erbB2, C-erbB3, and C-erbB4 in ovarian malignant neoplasms were 75.51%, 69.39%, and 65.31%, respectively, and they were higher than that in ovarian benign neoplasms (19.05%, 23.81%, and 23.81%, respectively) and control (21.05%, 15.79%, and 21.05%, respectively)(P< 0.05). (2) There was not significant difference between the expression of C-erbB2, C-erbB3, and C-erbB4 in ovarian malignant neoplasms and its pathologic type and grade (P >0.05). (3) The positive expression rates of C-erbB2, C-erbB3, and C-erbB4 in the patients with late stage or large amount of ascetic volume ( >500 ml) were 90.0% and 91.3%, respectively, and those also were higher than that in early stage or ascetic volume< 500 ml (P< 0.05). (4) The cumulative survival time of the patients with positive expression of C-erbB2 or C-erbB4 was longer than that without expression (P< 0.01). The analysis of Cox model showed that expressions of C-erbB2 and C-erbB4 in ovarian malignant were also independent prognosis factors for ovarian cancer. CONCLUSION: The C-erbB family would play an importation role in ovarian malignant neoplasms, and also was related to poor prognosis in ovarian cancer.
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