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Biomedical subjects

B Liang

Publications and source records attributed to B Liang.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Efficacy of ablendazole emulsion in treatment of 212 patients with cystic echinococcosis].

OBJECTIVE: To verify the efficacy of abendazole emulsion, a new formulation of abendazole, in treatment of human cystic echinococcosis. METHODS: 212 patients with liver cystic echinococcosis were treated orally with albendazole emulsion at a daily dose of 10 mg/kg or 12.5 mg/kg for 3 to 12 months or over one year. The therapeutic efficacy was mainly evaluated by image feature examined with B ultrasound examination, a short-term efficacy at the completion of treatment and a long-term efficacy followed-up for 1-4 years. RESULTS: In 212 patients treated with albendazole emulsion at a daily dose of 10 mg/kg and 12.5 mg/kg, the average cure rate, improved rate and the rate of no avail were 74.5%, 99.1% and 0.9% respectively after termination of the treatment, and the average long-term rates were 83.1%, 89.3% and 0.6% respectively. Recurrence occurred in 18 patients(10.2%). The results indicated that the best efficacy was seen in patients treated with albendazole 12.5 mg/kg daily for 9 months. Better response was also found when the recurrent patients were re-treated with albendazole. CONCLUSION: The efficacy of albendazole emulsion on patients with liver cystic echinococcosis is much better than that of albendazole tablet or capsule and mebendazole. Meanwhile, the efficacy of albendazole emulsion is stable with less adverse effects. The results suggest that albendazole emulsion could be the drug of choice for treatment of cystic hydatid disease.

Albendazole↗
PubMed2000

Progress toward the total synthesis of callipeltin A (I): asymmetric synthesis of (3S,4R)-3,4-dimethylglutamine.

[reaction:see text] During the total synthesis of the novel cyclic depsipeptide callipeltin A (1), the unit (3S,4R)-3,4-dimethylglutamine, was successfully synthesized by asymmetric Michael addition and subsequent electrophilic azidation. The key feature of this approach is the generation of three adjacent stereogenic centers using the same camphorsultam chiral auxiliary.

Depsipeptides↗
PubMed2000

Autoantibody responses and pathology regulated by B7-1 and B7-2 costimulation in MRL/lpr lupus.

The activation of T lymphocytes requires both Ag-mediated signaling through the TCR as well as costimulatory signals transmitted through B7-1 and/or B7-2 with CD28. The interference of B7-mediated costimulatory signals has been proposed as one immunotherapeutic intervention for the prevention autoimmune disease. This study has examined autoantibody responses and autoimmune pathology in a murine model of human systemic lupus erythematosus (SLE), the MRL-lpr/lpr mouse, genetically deficient in B7-1 or B7-2, or in mice treated with B7-1/B7-2 blocking Abs. In contrast to other studies of murine models of SLE, MRL-lpr/lpr mice treated with B7 blocking Abs exhibit strong anti-small nuclear ribonucleoprotein (snRNP) and anti-DNA autoantibody responses with some changes in isotype switching as compared with untreated animals. All MRL-lpr/lpr mice deficient in B7-1 or B7-2 produce anti-snRNP and anti-DNA titers with isotypes virtually identical with wild-type animals. However, the absence of B7-2 costimulation did interfere with the spontaneous activation and the accumulation of memory CD4+ or CD8+ T lymphocytes characteristic of wild-type MRL-lpr/lpr mice. IgG and C3 complement deposition was less pronounced in the kidneys of B7-2 deficient MRL-lpr/lpr mice, reflecting their lessor degree of glomerulonephritis. By comparison, B7-1-deficient MRL-lpr/lpr mice had more severe IgG and C3 deposits in glomeruli.

Animals↗
PubMed2000

Seasonality of matings and births in captive Sichuan golden monkeys (Rhinopithecus roxellana).

This study, based on three years of mating behavior observations and 10 years of birth records, reveals that Sichuan golden monkeys in captivity displayed a marked seasonality of mating behavior and births. The peak of matings occurred around October, and births occurred in March-June. The birth peak followed the mating peak by six to seven months. This seasonal cycle of matings and births was similar to observations made in the wild, where both temperature and food resources were favorable in spring. The time delay between peaks of matings and births was the approximate length of gestation, which implies that mating behavior was concentrated during the period of conception. We suggest that the peak of births in captive Sichuan golden monkeys occurred during the time of year with the most favorable environmental conditions, and the peak of matings corresponded with the period of conception.

Animals↗
PubMed2000

Molecular mimicry and the role of B lymphocytes in the processing of autoantigens.

The immune system has evolved several mechanisms that provide lymphocytes with the intelligence to ignore self proteins while attacking foreign pathogenic agents. Notably, B and T lymphocytes that encounter self antigen at either the inappropriate levels or affinity are usually instructed to perish or become anergized. However, the presence of autoimmune disease suggests that the induction of self tolerance is not foolproof. In fact, autoreactive cells are now found to be normal inhabitants of the B and T lymphocyte repertoire. This review examines how foreign peptides which resemble self proteins can elicit autoimmunity that is amplified to many sites on a target autoantigen. In particular, B lymphocytes initiated by foreign molecular mimics can process and present self peptides in the shaping of autoimmune T cell responses.

Animals↗
PubMed2000

A structured database and image acquisition system in support of palynological studies: CHITINOS.

CHITINOS is a microfossil image and data acquisition system developed to support palynologists from field work to report production. The system is intended for chitinozoans, but it can also accommodate other fossil groups. Thanks to its client-server architecture, the system can be accessed by multiple users. The database can be filled with data acquired during palynological work or taken from the literature. The system allows for the easy input, update, management, analysis and retrieval of paleontological data to enable the paleontologist to elucidate paleogeographic patterns, changes in biodiversity and taxonomic differentiations. Query and plot interfaces are intended for report production. The system was designed as the basis of a knowledge expert system by providing a new perspective in the interpretation of interrelated data.

Journal Article↗
PubMed2000

The effect of fenofibrate treatment on endothelium-dependent relaxation induced by oxidative modified low density lipoprotein from hyperlipidemic patients.

The objective of the research project was to investigate whether fenofibrate treatment may alter the biochemical content of the oxidized LDL and consequently its ability to impair the endothelium-dependent relaxation in hyperlipidemic patients. We hypothesized that fenofibrate treatment of hyperlipidemic patients may attenuate the ability of their oxidized LDL to impair the endothelium-dependent relaxation of the blood vessels as a consequence of fenofibrate-induced changes to the content and composition of lysoPC in the LDL molecule. Hyperlipidemic patients (Type IIb and Type IV) were recruited from the Lipid Clinic, HSC, Winnipeg, Canada, for this study. A blood sample was taken immediately after the recruitment, a second sample was taken after 6 weeks of dietary treatment, and a third sample was taken after 8 weeks of fenofibrate treatment. LDL was isolated from the plasma and oxidized by copper sulfate. Fenofibrate was shown to be highly effect in the reduction of total cholesterol, LDL cholesterol and triglycerides in these patients. Fenofibrate treatment also caused the attenuation of impairment of endothelium-dependent relaxation by the oxidized LDL from these patients. A slight reduction of lysophosphatidylcholine level was also found in the oxidized LDL of the fenofibrate treated patients, relative to LDL isolated after dietary treatment. In addition there were no changes in the fatty acid levels of the lysophosphatidylcholine isolated from LDL. Taken together, our results suggest that while the reduced lysophosphatidylcholine levels may contribute to the attenuated impairment of the endothelium-dependent relaxation of the aortic ring, other unidentified factors impacted by fenofibrate are likely to contribute to the attenuated effects.

Acetylcholine↗
PubMed2000

Clinical pharmacokinetic and in vitro combination studies of nolatrexed dihydrochloride (AG337, Thymitaq) and paclitaxel.

A clinical study of nolatrexed dihydrochloride (AG337, Thymitaq) in combination with paclitaxel was performed. The aims were to optimize the schedule of administration and determine any pharmacokinetic (PK) interactions between the two drugs. In vitro combination studies were performed to assist with schedule optimization. Three patients were entered on each of three different schedules of administration of the two drugs: (1) paclitaxel 0-3 h, nolatrexed 24-144 h; (2) nolatrexed 0-120 h, paclitaxel 48-51 h; (3) nolatrexed 0-120 h, paclitaxel 126-129 h. Paclitaxel was administered at a dose of 80 mg m(-2) over 3 h and nolatrexed at a dose of 500 mg m(-2) day(-1) as a 120-h continuous intravenous infusion. Plasma concentrations of both drugs were determined by high performance liquid chromatography. In vitro growth inhibition studies using corresponding schedules were performed using two head and neck cancer cell lines. In both HNX14C and HNX22B cell lines, synergistic growth inhibition was observed on schedule 2, whereas schedules 1 and 3 demonstrated antagonistic effects. In the clinical study, there was no effect of schedule on the pharmacokinetics of nolatrexed. However, patients on schedules 1 and 3 had a higher clearance of paclitaxel (322-520 ml min(-1) m(-2)) than those on schedule 2 (165-238 ml min(-1) m(-2)). Peak plasma concentrations (1.66-1.93 vs. 0.86-1.32 microM) and areas under the curve (392-565 vs. 180-291 microM min(-1)) of paclitaxel were correspondingly higher on schedule 2. The pharmacokinetic interaction was confirmed by studies with human liver microsomes, nolatrexed being an inhibitor of the major routes of metabolism of paclitaxel. Toxicity was not schedule-dependent. Nolatrexed and paclitaxel may be safely given together when administered sequentially at the doses used in this study. Studies in vitro suggest some synergy, however, due to a pharmacokinetic interaction, paclitaxel doses should be reduced when administered during nolatrexed infusion.

Adult↗
PubMed2000

[Sample preconcentration technique in capillary electrophoresis].

The methods of improving the detection sensitivity in analysis of trace level components by sample preconcentration technique including sample stacking, field-amplified sample injection, isotachophoresis etc. are reviewed, and 67 references are cited.

Electrophoresis, Capillary↗
PubMed2000

[Radiological study of orbital foreign body].

OBJECTIVE: To study the factors influencing of foreign body. METHODS: 527 cases of orbital foreign body was analysed and the relationship between foreign body and projection position or projection angle was retrospectively reviewed. RESULTS: Foreign body in 13 cases was found in the lateral radiogram(No foreign body in the posteroanterior radiogram). In 12 cases foreign body was found in the Belot's radiogram(No foreign body in P. A. and lateral radiognam). In ten cases foreign body was found in the Vogts radiogram (No foreign body in P. A., lateral, Belot's radiogram). In the first radiogram, one case was found to have foreign body in the Lateral but P. A. In the second radiogram, just the reverse of above. CONCLUSION: The image of foreign body was influenced by projection position and projection angle between foreign body and X-ray. The patients must take Belot's or Vogt's radiogram except routine P. A. and Lateral radiogram. Sometimes the patients should be taken more radiogram after moving the eye ball direction in order to find the small and flact foreign body.

Adolescent↗
PubMed1999

The first total synthesis of (-)-tamandarin A.

[formula: see text] Tamandarin A (1), a newly isolated natural product similar in structure to didemnin B (2), was shown to be somewhat more active in vitro than 2 against pancreatic carcinoma with an ED50 value 1.5 to 2 ng/mL. We report here the first total synthesis of 1. The key steps include a practical stereoselective synthesis of the Hiv-isostatine unit, high-yielding linear precursor formation, a successful macrocyclization, and coupling of the macrocycle with the side chain to afford tamandarin A (1).

Antineoplastic Agents↗
PubMed1999

B7 costimulation in the development of lupus: autoimmunity arises either in the absence of B7.1/B7.2 or in the presence of anti-b7.1/B7.2 blocking antibodies.

Costimulatory molecules, termed B7.1 and B7.2, are present on the surfaces of APC and are important for the activation of T lymphocytes specific for both foreign Ags and autoantigens. We have examined the role of B7 costimulation in the MRL-lpr/lpr murine model of human systemic lupus erythematosus. MRL-lpr/lpr mice receiving both anti-B7.1 and anti-B7.2 Abs expressed significantly lower anti-small nuclear ribonucleoprotein particles (snRNP) and anti-dsDNA autoantibodies than did untreated mice. Anti-B7.2 Ab treatment alone inhibited anti-dsDNA autoantibody expression while having no effect on anti-snRNP autoantibody expression. Anti-B7.1 Ab treatment alone did not change the expression of either anti-snRNP or anti-dsDNA autoantibodies. Parallel studies performed in MRL-lpr/lpr mice genetically deficient in either B7.1 or B7.2 expressed autoantibody profiles comparable to those found in wild-type MRL-lpr/lpr mice. However, B7.1-deficient MRL-lpr/lpr mice exhibited distinct and more severe glomerulonephritis while B7.2-deficient MRL-lpr/lpr mice had significantly milder or absent kidney pathology as compared with age-matched wild-type mice. These studies indicate that each B7 costimulatory signal may control unique pathological events in murine systemic lupus erythematosus that may not always be apparent in autoantibody titers alone.

Animals↗
PubMed1999

TGF-beta(1), regulation of alzheimer amyloid precursor protein mRNA expression in a normal human astrocyte cell line: mRNA stabilization.

The transforming growth factor, TGF-beta(1), has been found to be increased in the central nervous system of Alzheimer's disease (AD) patients, elevates amyloid precursor protein (APP) mRNA levels in rat primary astrocytes, and may initiate or promote the deposition of amyloid-beta (Abeta) peptide in AD. Excess APP production in AD, which potentially leads to amyloidogenesis, is in part due to over expression of APP mRNA. The production of APP in a normal human cell line in contrast to transformed or animal cells provides a meaningful model to study the regulation of APP gene expression by cytokines that promotes amyloidogenesis. Here, we report that TGF-beta(1) treatment of human astrocytes markedly elevated APP mRNA levels, and also increased the half-life of APP message by at least five-fold. Under this condition, as detected by mobility shift and UV cross-linking analysis, a novel 68 kDa RNA-protein complex was formed, involving an 81 nucleotide (nt) fragment within the 3'-untranslated region (UTR), but not the 5'-UTR and coding region of APP mRNA. Insertion of the 3'-UTR onto the chloramphenicol acetyl transferase (CAT) mRNA conferred TGF-beta(1) mediated mRNA stability in transfected human astrocytes. On the other hand, the same insert carrying a deletion of the APP mRNA cis-element fragment had no effect on CAT mRNA stability. A model of APP mRNA regulation is presented in which TGF-beta(1) induced stabilization of APP message involves the binding activity of a 68 kDa RNA-protein complex within the 3'-UTR, which is likely linked to a reduction in the rate of APP mRNA decay.

3' Untranslated Regions↗
PubMed1999

Group II nucleopolyhedrovirus subgroups revealed by phylogenetic analysis of polyhedrin and DNA polymerase gene sequences.

Two major clades, designated Groups I and II, of nucleopolyhedroviruses (NPVs) from lepidopteran hosts have been previously identified. To reveal more detailed relationships, a series of DNA polymerase nucleotide sequences from the taxa MbMNPV, SeMNPV, HzSNPV, HearNPV, SpltNPV, BusuNPV, and OranNPV have been determined using a polymerase chain reaction (PCR)-based approach. This technique enabled gene sequence determination using microliter samples of NPV-infected insect cadavers. Polyhedrin genes from HearNPV, OranNPV, SeMNPV, and SpltNPV were also isolated and sequenced using a similar approach. These sequences, together with other database entries, were aligned for positional homology of peptide sequences. Phylogenetic analysis of DNA polymerase molecular sequence alignments supports LdMNPV as a taxon of Group II and three Group II subclades, designated A, B, and C. Comparison of DNA polymerase trees with those estimated from occlusion protein molecular sequences enabled identification of three subclades of Group II. These are Subgroup II-A [MbMNPV, LeseNPV, MacoNPV, PaflNPV, SeMNPV, SpltNPV (India isolate), SfMNPV]; Subgroup II-B [SpliNPV, SpltNPV (Japan isolate), SpltNPV (Queensland isolate), and possibly HzSNPV, HearNPV, and ManeNPV], and Subgroup II-C [OpSNPV, OranNPV (S-type), BusuNPV (S-type), and possibly EcobNPV (S-type)]. Notably, all Subgroup II-A taxa are from noctuid hosts. Correlations of virus and host evolution within Group II taxa are discussed. The methods and data developed in this study will allow rapid sequencing of NPV DNA polymerase genes.

Amino Acid Sequence↗
PubMed1999

Body distribution of camptothecin solid lipid nanoparticles after oral administration.

PURPOSE: The aim of this study was to investigate the specific changes in body distribution of camptothecin (CA) through incorporation into solid lipid nanoparticles (SLN) by peroral route. METHODS: Camptothecin loaded solid lipid nanoparticles (CA-SLN) coated with poloxamer 188 were produced by high pressure homogenization. The CA-SLN were characterized by transmission electron microscopy and electrophoretic mobility measurement. In vitro release characteristics of camptothecin from CA-SLN were studied at different pH media. The concentration of camptothecin in organs was determined using reversed-phase high-performance liquid chromatography with a fluorescence detector after oral administration of CA-SLN and a camptothecin control solution (CA-SOL). RESULTS: Our results showed that CA-SLN had an average diameter 196.8 nm with Zeta potential of -69.3 mV. The encapsulation efficiency of camptothecin was 99.6%, and in vitro drug release was achieved up to a week. There were two peaks in the camptothecin concentration-time curves in plasma and tested organs after oral administration of CA-SLN. The first peak was the result of free drug and the second peak was indicative of gut uptake of CA-SLN after 3 hours. In tested organs, the area under curve (AUC) and mean residence time (MRT) of CA-SLN increased significantly as compared with CA-SOL, and the increase of brain AUC was the highest among all tested organs. CONCLUSIONS: The results indicate SLN could be a promising sustained release and targeting system for camptothecin or other lipophilic antitumor drugs after oral administration.

Administration, Oral↗