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Biomedical subjects

Li Li

Publications and source records attributed to Li Li.

At least 685 records · Page 38Linked to original sources
PubMed2000

Isolation and Characterization of Microsatellite Loci for Striped Bass (Morone saxatilis).

Genetic variation has been difficult to detect in striped bass (Morone saxatilis). Therefore, we identified and characterized 13 microsatellite loci to provide additional genetic markers for striped bass. Microsatellites were identified by screening a striped bass genomic library or by using primers developed for European sea bass (Dicentrarchus labrax) microsatellite loci. We found that 6 of the 13 microsatellite loci were polymorphic in DNA samples obtained from wild populations of striped bass. The number of alleles per locus varied from 3 to 12, and the observed heterozygosities ranged from 0.55 to 0.78. These results indicate that microsatellite loci provide more alleles and higher heterozygosities than other genetic markers developed for striped bass.

Journal Article↗
PubMed2000

[The Role of Calcium Ion in Apotopsis of HL-60 Cells Induced by VP-16]

To study the significance of calcium in the apoptosis of HL-60 cells induced by VP-16, the technology of flow cytometry, confocal laser scanning microscopy and Western blot were used. The results showed that VP-16 could induced the apoptosis of HL-60 cells and transient increase of intracellular calcium concentration; EGTA [ethylene glycol-bis(2-aminoethyl)-N,N,N',N'-tetraacetic acid], that could combine the extracellular calcium, did not prevent the apoptosis of HL-60 cells. BAPTA-AM [1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxy-methyl) ester], however, a chelating agent of intracellular calcium ions, could prevent apoptosis and the release of cytochrome C from HL-60 cells. It was concluded that the calcium plays an important role in apoptosis and the release of cytochrome C.

Journal Article↗
PubMed2000

[Expression of TFAR19 in Apoptotic Processes of Jurkat Cells Induced with Various Methods]

A new apoptosis-related gene TFAR19 was recently cloned. A primary functional analysis indicates its role in the apoptotic process of TF-1 cells. To clarify TFAR19 was involved in which apoptotic pathway, the changes in TFAR19 expression were observed during the apoptotic processes of Jurkat cells induced with various methods: serum deprivation, VP-16 treatment and Fas McAb activation. Then TFAR19 expression in Jurkat cells was detected with flow cytometry and Western blot, and TFAR19 mRNA with RT-PCR. Our results showed that expression of TFAR19 in Jurkat cells was increased at 12 hours after serum deprivation, 2 hours after VP-16 treatment and 2 hours after Fas McAb activation, respectively. These observations suggested that TFAR19 was involved in the apoptotic process of Jurkat cells induced with serum deprivation, DNA destruction and death receptor activation. It might take effect in the early apoptotic process. TFAR19 is a participant of the "final common pathway" in the apoptotic pathway.

Journal Article↗
PubMed1999

CT arterial portography and CT hepatic arteriography in detection of micro liver cancer.

AIM:To recognize the characteristic findings of micro-liver cancer (MLC) and to evaluate the effect of CT arterial portography (CTAP) and CT hepatic arteriography (CTHA) in diagnosis of MLC.METHODS:Between April 1996 to December 1998, CTAP and CTHA were performed in 12 patients with MLC, which were not detected by conventional CT examinations. After CTHA, 3mL-5mL mixture of lipiodol, doxorubicin and mitoycin C were injected into hepatic artery through the catheter, and the followed up by CT three or four weeks later (Lipiodol CT Lp-CT).RESULTS:A total of 22 micro-tumors (0.2cm-0.6cm in diameter) were detected in 12 patients, which manifested as small perfusion defects in CTAP and small round enhancement in CTHA. The rate of detectability of CTAP and CTHA was 68.2% (15/22) and 77.3% (17/22) respectively, and the rate of the simultaneous use of both procedures reached 86.4% (19/22).All micro-tumors were demonstrated as punctate lipiodol deposit foci in Lp-CT. After Lp-CT, the elevated serum level of alpha-fetoprotein (AFP) dropped to the normal level in all patients.CONCLUSION:The CTAP and CTHA are the most sensitive imaging methods for detecting micro-liver cancer.Confirmed by the change of the elevated serum AFP level and lipiodol deposit foci in Lp-CT, small perfusion defects in CTAP and puntuate enhancement in CTHA may suggest micro-liver cancer.

Journal Article↗
PubMed1999

Sequencing of a 3.3 kb Fragment from LsNPV Genome and Comparison of Its Genome Structure with Other Two NPVs.

A fragment (3 336 bp) of LsNPV genome has been sequenced. It contains three complete ORFs (ORF2, ORF3, ORF4) and two incomplete ORFs (ORF1, ORF5). Comparing with AcNPV genome it was found that ORF1 coding product was homologous with P94 protein ORF3, ORF4 and ORF5 were homologous with ORF60, ORF59 and ORF57 of AcNPV respectively. Their transcriptional orientations are identical. It is suggested that the ORF2 is a new gene of LsNPV genome. The results showed that the genomic structure of LsNPV is quite different with that of other baculovirus compared. This may be helpful for investigation of the LsNPV molecular biology.

Journal Article↗
PubMed1998

Hepatic adenylate energy charge levels in patients with hepatoma after hepatic artery embolization.

AIM:To evaluate hepatic energy charge levels of the patients with hepatoma after hepatic artery embolization and its relation to postoperative complications.METHODS:Sixty-nine patients with hepatoma were continuously measured for their arterial blood ketone body ratio (AKBR) and compared with their postoperative clinical course or conventional liver function test after various hepatic artery embolization.RESULTS:AKBR in high radiation dose or jaundice group drastically decreased at 1-3 days and recovered slowly. Patients were classified into three groups according to the value of AKBR: group A (35 cases), AKBR remained higher than 0.7; group B (31 cases), AKBR had transiently dropped to 0.4-0.7 and then increased to preoperative value; and group C (3 cases), AKBR decreased steadily to below 0.4.The occurrence rate of various complications were 5.7%, 32.3% and 100% in the three groups, respectively (P < 0.005).CONCLUSION:The AKBR which reflects hepatic mitochondria redox state is more reliable as a direct indicator to assess hepatic tolerance for embolization than routine liver function test.

Journal Article↗
PubMed1998

Segmental transcatheter arterial embolization for primary hepatocellular carcinoma.

AIM:To evaluate the therapeutic effects of segmental transcatheter arterial embolization for primary hepatocellular carcinoma, and to recognize the menifestation and clinical value of lipiodol overflow into portal veins surrounding the tumors.METHODS:A total of 50 cases of nonresectable primary hepatocellular carcinoma underwent segmental transcatheter arterial embolization. Two methods of superselective segmental catheterization were used, one was the method of wire-guiding, and the other the technic of co-axial infusion catheter.RESULTS:The 1-, 2-, 3- and 4-year cumulative survival rates of 50 cases with segmental transcatheter arterial embolization for primary hepatocellular carcinoma were 83.8%, 65.4%, 42.9% and 24.5% respectively. The in cidence of the lipiodol overflow into portal veins was 64%. The overflow of lipiodol intoportal veins, represented as 3-5 grade branches of portal veins visualized by lipiodol, was star-like or tree-like , and there was a relatively large vessel in the center surrounded with radicalized small branches of vessels.CONCLUSION:The lipiodol overflow into portal veins was one of the signs of complete embolization for tumors, and may play a partial role in embolizating the portal venous supply for hepatocellular carcinoma.

Journal Article↗
PubMed1998

Findings of non-pathologic perfusion defects by CT arterial portography and non-pathologic enhancement of CT hepatic arteriography.

AIM:To recognize the characteristic findings of non-pathologic perfusion defects with CT arterial portography (CTAP) and nonpathologic enhancement found in CT hepatic arteriography (CTHA).METHONDS:The manifestations of nonpathologic perfusion defects with CTAP and non pathologic enhancement found in CTHA were analyzed in 50 patients with primary hepatocellular carcinoma.RESULTS:The false-positive rate of perfusion defects detected in CTAP was 15.1% The shapes of perfusion defects were peripheral wedge, small, round, and patchy. The occurrence rate of non-pathologic enhancement found in CTHA was 22.0%. The shapes of non-pathologic enhancement were small, round, irregular, and wedge.CONCLUSION:There was high frequency of non-pathologic perfusion defects detected with CTAP and non-pathologic enhancement found in CTHA. The simultaneous use of both procedures may help decrease the false-positive rate, and increase the veracity of diagnosis for hepatocellular carcinoma.

Journal Article↗
PubMedDate not supplied

Abstinence trajectories among treated crack cocaine users.

This article reports findings from a study that investigated treatment outcomes among crack/cocaine users over a 18-month period. From a cohort of 229 subjects, three groups emerged: (1) those who had reported ongoing, stable abstinence from crack/cocaine; (2) those who had consistently used during the period; and (3) those who reported cycling between abstinence and use during the follow-up period. Analyses of variance (ANOVA) were conducted to compare the three groups in terms of intake characteristics, including demographic profile, previous treatment, motivational factors, and functioning in seven Addiction Severity Index (ASI) domains. Length of time involved in aftercare and Twelve Step participation after treatment were also contrasted among the three groups. Results showed that subjects who achieved sustained abstinence from crack/cocaine also did better in other domains such as employment, family, legal, and psychiatric than others. Stable abstinence was also significantly associated with a longer period of aftercare and frequent attendance at Twelve Step programs. Logistic regression analyses further estimated the significant impact of the posttreatment factors on the achievement of sustained abstinence. The implications of these findings for treatment services research are discussed.

Adult↗
PubMedDate not supplied

Upregulated expression of a unique gene by hepatitis B x antigen promotes hepatocellular growth and tumorigenesis.

Hepatitis B x antigen (HB x Ag) is a trans-activating protein that may be involved in hepatocarcinogenesis, although few natural effectors of HB x Ag that participate in this process have been identified. To identify additional effectors, whole cell RNA isolated from HB x Ag-positive and HB x Ag-negative HepG2 cells were compared by polymerase chain reaction select cDNA subtraction, and one clone, upregulated gene, clone 11 (URG11), was chosen for further characterization. Elevated levels of URG11 mRNA and protein were observed in HB x Ag-positive compared to HB x Ag-negative HepG2 cells. Costaining was observed in infected liver (P < 0.01). URG11 stimulated cell growth in culture (P < 0.01), anchorage-independent growth in soft agar (P < 0.001), and accelerated tumor formation (P < 0.01), and yielded larger tumors (P < 0.02) in SCID mice injected subcutaneously with HepG2 cells. These data suggest that URG11 is a natural effector of HB x Ag that may promote the development of hepatocellular carcinoma.

Amino Acid Sequence↗
PubMedDate not supplied

Parallel approach for solution-phase synthesis of 2-quinoxalinol analogues and their inhibition of LPS-induced TNF-alpha release on mouse macrophages in vitro.

A parallel solution-phase synthesis of 2-quinoxalinol analogues is described. The key step-simultaneous reductions of m-Ar(NO2)2 to m-Ar(NH2)2 was investigated extensively. We obtained preliminary pharmacological activity of those analogues for the inhibition of LPS-induced TNF-alpha release on mouse macrophage in vitro. Two compounds revealed inhibitory activity, with IC50 values of 0.40 microM (7-amino-6-[(3-methoxypropyl)amino]-3-methyl-2-quinoxalinol) and 2.2 microM (7-amino-6-[(3-butoxypropyl)amino]-3-methyl-2-quinoxalinol), respectively.

Animals↗
PubMedDate not supplied

Multistep parallel synthesis of substituted 5-aminobenzimidazoles in solution phase.

An efficient solution-phase parallel synthesis of multisubstituted 5-aminobenzimidazoles is described. The two fluorine atoms of 1,5-difluoro-2,4-dinitrobenzene (DFDNB) are sequentially and quantitatively replaced by nucleophiles. Simultaneous reduction of aromatic m-dinitro groups by Pd-C/HCOONH(4) results in 2,4,5-benzenetriamines, which are continuously condensed with aldehydes to successfully construct the benzimidazole ring without additional oxidants. The free aromatic amino group is further modified by anhydrides, isocyanates, isothiocyanates, and sulfonyl chlorides. All the reactions involved here are highly effective in giving the desired products at room temperature. Four diversity points are introduced in the final products.

Journal Article↗
PubMedDate not supplied

Screening and identification of linear B-cell epitopes and entry-blocking peptide of severe acute respiratory syndrome (SARS)-associated coronavirus using synthetic overlapping peptide library.

A 10-mer overlapping peptide library has been synthesized for screening and identification of linear B-cell epitopes of severe acute respiratory syndrome associated coronavirus (SARS-CoV), which spanned the major structural proteins of SARS-CoV. One hundred and eleven candidate peptides were positive according to the result of PEPscan, which were assembled into 22 longer peptides. Five of these peptides showed high cross-immunoreactivities (approximately 66.7 to 90.5%) to SARS convalescent patients' sera from the severest epidemic regions of the China mainland. Most interestingly, S(471-503), a peptide located at the receptor binding domain (RBD) of SARS-CoV, could specifically block the binding between the RBD and angiotensin-converting enzyme 2, resulting in the inhibition of SARS-CoV entrance into host cells in vitro. The study demonstrated that S(471-503) peptide was a potential immunoantigen for the development of peptide-based vaccine or a candidate for further drug evaluation against the SARS-CoV virus-cell fusion.

Amino Acid Sequence↗
PubMedDate not supplied

Benzofused tricycles based on 2-quinoxalinol.

This paper describes our recent efforts to synthesize novel compound scaffolds integrating 2-quinoxalinol with privileged structures of 1,3-dihydro-benzoimidazol-2-one, 1,3-dihydro-benzoimidazole-2-thione, 3-hydroxy-1H-quinoxalin-2-one, 2H-benzo[1,4]oxazin-3-ol, 2H-benzo[1,4]thiazin-3-ol, and 1,3,4,5-tetrahydro-benzo[1,4]diazepin-2-one, respectively. Eight novel benzofused tricycles and their substituent diversity points were developed. These include pyrazino[2,3-g]quinoxaline-2,8-diol (I), 3-hydroxy-6,8,9,10-tetrahydro-1,4,6,10-tetraaza-cyclohepta[b]naphthalen-7-one (II), 6-hydroxy-4H-1-oxa-4,5,8-triaza-anthracen-3-one (III), 6-hydroxy-4H-1-thia-4,5,8-triaza-anthracen-3-one (IV), 6-hydroxy-1,1-dioxo-1,4-dihydro-2H-1lambda(6)-thia-4,5,8-triaza-anthracen-3-one (V), 6-hydroxy-1,3-dihydro-imidazo[4,5-g]quinoxalin-2-one (VI), 6-hydroxy-1,3-dihydro-imidazo[4,5-g]quinoxaline-2-thione (VII), and 7-hydroxy-1,4-dihydro-pyrazino[2,3-g]quinoxaline-2,3-dione (VIII). This strategy of integrating two benzofused privileged structures into one molecule may provide a greater chance for the discovery of novel lead compounds.

Anthracenes↗
PubMedDate not supplied

Synthesis of diverse benzo[1,4]oxazin-3-one-based compounds using 1,5-difluoro-2,4-dinitrobenzene.

This paper discusses the synthesis of benzo[1,4]oxazin-3-one-based compounds from 1,5-difluoro-2,4-dinitrobenzene (1), including benzo[1,4]oxazin-3-ones (5-11) and five novel benzo[1,4]oxazin-3-one-based tricycles: 6-hydroxy-4H-1-oxa-4,5,8-triazaanthracen-3-one (14), 3,8-dihydro-5-oxa-1,3,8-triazacyclopenta-[b]-naphthalene-7-one (15, 17, 21), 3,8-dihydro-5-oxa-1,2,3,8-tetraazacylopenta[b]-naphthalene-7-one (16, 20), 3,8-dihydro-1H-5-oxa-1,3,8-triazacyclopenta[b]-naphthalene-2,7-dione (18, 22), and 5,8-dihydro-4H-1-oxa-4,5,8-triazaanthracene-3,6,7-trione (19). Finally, a chemical library based on 15 was synthesized in parallel solution-phase reactions.

Benzoxazines↗
PubMedDate not supplied

Comparative study of the ability of mesenchymal stem cells derived from bone marrow, periosteum, and adipose tissue in treatment of partial growth arrest in rabbit.

This study evaluates the ability of MSCs isolated from different origins--bone marrow, periosteum, or fat--to treat partial growth arrest in immature (6-week-old) New Zealand White rabbits. Up to 50% of the medial half of the proximal physis of the tibia was excised in these New Zealand White rabbits. Three weeks later, the bony bridge was excised, and fibrin glue with and without MSCs were transferred into the physeal defect of different rabbits. Contralateral tibias, without undergoing operation, served as self-control. Four groups of rabbits were involved in the study. Each group was injected separately with bone marrow-derived MSCs (group I), periosteum-derived MSCs (group II), fat-derived MSCs (group III), and fibrin glue alone (control, group IV). The rabbits were killed 8 and 16 weeks postoperatively. Clinical, radiological, and histological analyses were subsequently performed. Similar proliferative rates for three MSCs were demonstrated on days 4, 7, and 11 of primary culture. However, MSCs derived from bone-marrow and periosteum appeared to be more homogeneous than that from fat. All MSCs demonstrated chondrogenic and osteogenic differentiation potentials in vitro. The tibias in groups I and II showed significant correction of varus angulation at 16 weeks. However, the varus angulation in group III remained significantly obvious when compared with group I (p < 0.05). The length discrepancies between operated and normal tibiae in groups I, II, and III were significantly corrected compared with control (p < 0.01). In conclusion, bone-marrow and periosteum yielded more homogenous MSCs than fat, providing better correction of physeal arrest in rabbits. The source of MSCs itself could influence the success in the treatment of growth arrest.

Adipose Tissue↗
PubMedDate not supplied

Chitin as a scaffold for mesenchymal stem cells transfers in the treatment of partial growth arrest.

To investigate the feasibility of using chitin, a natural polymer, as a scaffold to repair large growth plate defects (50% of physis) in immature rabbits, mesenchymal stem cells (MSCs) were harvested from periosteum. The compatibilities of chitin with the MSCs were investigated in vitro using immunohistochemistry and fluorescence confocal microscopy. The results showed high compatibilities of chitin. An experimental model of growth arrest was created by excising the medial half of the proximal growth plate of the tibia in 6-week-old New Zealand White rabbits. The physeal defect after excision of the bony bridge was transplanted either with no interposition (group 1), chitin alone (group 2), or chitin with MSCs (group 3). In groups 2 and 3, both angulatory deformities and length discrepancies of the tibia were corrected. The differences between group 3 and group 1 were greater than those between group 2 and group 1.

Animals↗