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Biomedical subjects

Jing Liu

Publications and source records attributed to Jing Liu.

At least 145 records · Page 8Linked to original sources

Phase I study of the sequential combination of interleukin-12 and interferon alfa-2b in advanced cancer: evidence for modulation of interferon signaling pathways by interleukin-12.

PURPOSE: To evaluate the safety of sequentially administered recombinant (r) human (h) interleukin-12 (IL-12) and interferon alfa-2b (IFN-alpha-2b) in patients with advanced cancer and to determine the effects of endogenously produced IFN-gamma on Janus kinase-signal transducer and activator of transcription (Jak-STAT) signal transduction in patient peripheral-blood mononuclear cells (PBMCs). PATIENTS AND METHODS: Forty-nine patients with metastatic cancer received rhIL-12 on day 1 and IFN-alpha-2b on days 2 to 6 of either a 14-day (n = 43) or a 7-day treatment cycle (n = 6). rhIL-12 was initially administered subcutaneously at a dose of 100 ng/kg, whereas IFN-alpha-2b was escalated from 1 to 10 million units (MU) in cohorts of three patients (1, 3, 5, 7, or 10 MU). rhIL-12 was subsequently administered intravenously (IV) in escalating doses (100 to 500 ng/kg) to achieve greater IFN-gamma production. Peripheral blood was drawn for measurement of plasma IFN-gamma and the induction of Jak-STAT signal transduction in PBMCs. RESULTS: No IL-12-or IFN-alpha-related dose-limiting toxicities were observed. There were no responses in 41 assessable patients. Five patients exhibited stable disease lasting 6 months or longer while on therapy. Optimal induction of IFN-gamma by IL-12 occurred after an IV dose of 250 ng/kg. Patient PBMCs exhibited increased levels of STAT1 after IL-12 administration. The peak level of IFN-gamma achieved with IL-12 therapy correlated with the peak level of intracellular STAT1 in patient PBMCs (r = 0.38, P = .021). CONCLUSION: The combination of rhIL-12 and IFN-alpha-2b can be administered sequentially with minimal toxicity. IV administration of rhIL-12 modulates IFN-alpha-induced Jak-STAT signal transduction in patient PBMCs.

Adult↗

Molecular cloning and mRNA expression of duck invariant chain.

In the present study we identified a duck invariant chain (Ii) cDNA, named duck Ii-1, by RT-PCR and RACE. It was 1190 bp in length and contained a 669 bp open reading frame. An alternative transcript encoding a thyroglobulin (Tg)-containing form of Ii, named duck Ii-2, was also found in duck. The putative amino acid sequence of duck Ii-1 showed an 82% similarity to chicken Ii-1 and about 60% similarity to its mammalian homologues. The similarity of the Tg domain between duck and chicken Ii-2 was 96%, and about 70% between duck and mammalian Ii. The result of RT-PCR showed that Ii mRNA was extensively expressed in various tissues. High levels of both Ii-1 and Ii-2 mRNA were observed in the spleen and bursa of Fabricius. The predicted three-dimensional (3D) structures of duck Ii trimerization and Tg domain are similar to the corresponding regions of human Ii analyzed by comparative protein modeling. These findings indicate that the two isoforms of duck Ii, which strongly expressed in the major immune organs, share structural identity with human Ii.

Amino Acid Sequence↗

Comparison of psychic emergence reactions after (+/-)-ketamine and (+)-ketamine in mice.

Ketamine is a racemic mixture containing equal parts of (+)-ketamine and (-)-ketamine. The ketamine enantiomorphs are different in anesthesia and psychic emergence reactions after anesthesia. Therefore, (+)-ketamine was compared with racemic ketamine in a number of randomized studies in volunteers and patients. However, their relations remain controversial. In the present studies, the psychic emergence reactions after injection of (+/-)-ketamine and (+)-ketamine were compared in mice. At equimolar doses, the (+)-isomers elicited episodes of hypnosis nearly 1.4-fold more potent than those of the racemic ketamine. After the administration of equihypnotic doses of (+)-ketamine and (+/-)-ketamine, the posthypnotic stimulation of locomotor activity, stereotype behavior and 5-HT-induced head-twitch response by the (+)-enantiomorph was significantly less intense than that of racemic ketamine. In receptor binding test, (+)-ketamine showed a higher affinity for NMDA receptor than that of (+/-)-ketamine, while (+)-ketamine and (+/-)-ketamine showed no affinity for dopamine D2 and serotonin 5-HT2 receptor. These results suggest that the (+)-ketamine has fewer posthypnotic side effects than (+/-)-ketamine when (+)-ketamine and (+/-)-ketamine were administered at equihypnotic dosages and that dopamine D2 and serotonin 5-HT2 receptor were not involved in the effects of (+)-ketamine and (+/-)-ketamine.

Anesthetics, Dissociative↗

Responses of antioxidant systems and LPO level to benzo(a)pyrene and benzo(k)fluoranthene in the haemolymph of the scallop Chlamys ferrari.

The effects of benzo(a)pyrene (BaP), benzo(k)fluoranthene (BkF) and their mixture on antioxidant enzyme activities and lipid peroxidation (LPO) levels of haemolymph of scallop (Chlamys ferrari) were studied. The superoxide dismutase (SOD) activities of 0.5 microg/L and 1.0 microg/L were significantly higher than controls (P<0.05), while it increased at beginning and then dropped (lower than controls) in the end at 10.0 microg/L and 50.0 microg/L PAHs groups. The catalase (CAT) activities were very little during the whole experimental time. The glutathione peroxidase (GPx) activities in each PAHs group all increased significantly (P<0.05). LPO levels all increased significantly (P<0.05) with time at each PAHs group except for the 0.5 microg/L group of less than hour 12. The toxicity of PAHs in a descending order was BaP>BkF>mixture of BaP and BkF. The changes in antioxidant enzyme activities and LPO level in haemolymph could reflect the detoxification functions and damage levels of whole organism.

Animals↗

Further study on the role of HSP70 on Ca2+ homeostasis in rat ventricular myocytes subjected to simulated ischemia.

We hypothesized that activation of heat shock protein 70 (HSP70) by preconditioning, which is known to confer delayed cardioprotection, attenuates the impaired handling of Ca(2+) at multiple sites. To test the hypothesis, we determined how the ryanodine receptor (RyR), sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA), and Na(+)/Ca(2+) exchanger (NCX) handled Ca(2+) in rat ventricular myocytes preconditioned with a kappa-opioid receptor agonist, U50488H (UP), followed by blockade of HSP70 with a selective antisense oligonucleotide and subsequently subjected to simulated ischemia. We determined the following: 1) the Ca(2+) transients induced by electrical stimulation and caffeine, which provide the overall picture of Ca(2+) homeostasis; 2) expression of RyR, SERCA, and NCX; and 3) Ca(2+) fluxes via NCX by the use of (45)Ca(2+) in the rat ventricular myocyte. We found that UP increased the activity of RyR, SERCA, and NCX and the expression of RyR and SERCA. These effects led to increases in the release of Ca(2+) from the sarcoplasmic reticulum via RyR and in the removal of Ca(2+) from the cytoplasm by reuptake of Ca(2+) to the SR via SERCA and by extrusion of Ca(2+) out of the cell via NCX. UP also reduced mitochondrial Ca(2+) accumulation. All of the effects of UP were either abolished or significantly attenuated by blockade of HSP70 synthesis with a selective antisense oligonucleotide. The results are evidence that activation of HSP70 by preconditioning improves the ischemia-impaired Ca(2+) homeostasis at multiple sites in the heart, which may be responsible, at least partly, for attenuated Ca(2+) overload, improved recovery in contractile function, and cardioprotection.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗

Genome sequence and gene expression of Bacillus anthracis bacteriophage Fah.

Fah, a lytic bacteriophage of Bacillus anthracis, is used widely in the former Soviet Union to identify anthrax bacteria. Here, we present the analysis of a 37,974 bp sequence of the Fah genome and examine gene expression of the phage in a model host, Bacillus cereus. Half of the Fah genome contains genes coding for structural proteins and host lysis functions in an arrangement typical of Syphoviridae. The other half of the genome contains genes coding for enzymes of viral genome replication and for numerous predicted transcription factors that are likely to regulate viral gene expression. Primer extension, in vitro transcription assays, and gene array analysis identified temporal classes of Fah genes and allowed location of viral promoters. Fah does not execute host transcription shut-off and relies on host RNA polymerase (RNAP) sigma(A) holoenzyme for transcription of its early and late genes. In addition, Fah encodes a sigma factor, sigma(Fah), a close relative of Bacillus sporulation factor sigma(F) that directs bacterial RNAP to at least one late viral promoter. sigma(Fah) is negatively regulated by host SpoIIAB, an anti-sigma factor that controls sporulation. Thus, sigma(Fah) may link phage gene expression to sporulation of the host.

Bacillus Phages↗

Expression of a recombinant anticoagulant C-type lectin-like protein ACFI in Pichia pastoris: heterodimerization of two subunits is required for its function.

ACFI is an anticoagulant C-type lectin-like protein (CLP) isolated from Agkistrodon acutus venom. To investigate the function of ACFI and its subunits, the cDNAs of two subunits were transformed and expressed in Pichia pastoris separately or together by a novel strategy using two vectors with different selectable markers. The results showed that recombinant homodimers were secreted when the subunits were expressed alone, while heterodimers (rACFI) were secreted when two subunits were co-expressed. The secreted proteins were purified from culture supernatants in one step by metal-chelating affinity chromatography with the yields of 1-4 mg/L. PAGE and ELISA showed that rACFI competed the binding of native ACFI for human factor X and IX with affinities of 1.6 and 30 nM, respectively. In addition, rACFI prolonged the activated partial thromboplastin time (APTT) in a concentration dependent manner as same as native ACFI. However, recombinant alpha or beta homodimers completely lost these activities, indicating the heterodimerization of two subunits is required for its function. It also suggests that P. pastoris is a promising system for structure-function studies of snake CLPs.

Agkistrodon↗

Characterization of a novel filarial serine protease inhibitor, Ov-SPI-1, from Onchocerca volvulus, with potential multifunctional roles during development of the parasite.

A novel filarial serine protease inhibitor (SPI) from the human parasitic nematode Onchocerca volvulus, Ov-SPI-1, was identified through the analysis of a molting third-stage larvae expressed sequence tag dataset. Subsequent analysis of the expressed sequence tag datasets of O. volvulus and other filariae identified four other members of this family. These proteins are related to the low molecular weight SPIs originally isolated from Ascaris suum where they are believed to protect the parasite from host intestinal proteases. The two Ov-spi transcripts are up-regulated in the molting larvae and adult stages of the development of the parasite. Recombinant Ov-SPI-1 is an active inhibitor of serine proteases, specifically elastase, chymotrypsin, and cathepsin G. Immunolocalization of the Ov-SPI proteins demonstrates that the endogenous proteins are localized to the basal layer of the cuticle of third-stage, molting third-stage, and fourth-stage larvae, the body channels and multivesicular bodies of third-stage larvae and the processed material found between the two cuticles during molting. In O. volvulus adult worms the Ov-SPI proteins are localized to the sperm and to eggshells surrounding the developing embryos. RNA interference targeting the Ov-spi genes resulted in the specific knockdown of the transcript levels of both Ov-spi-1 and Ov-spi-2, a loss of native proteins, and a significant reduction in both molting and viability of third-stage larvae. We suggest the Ov-SPI proteins play a vital role in nematode molting by controlling the activity of an endogenous serine protease(s). The localization data in adults also indicate that these inhibitors may be involved in other processes such as embryogenesis and spermatogenesis.

Amino Acid Sequence↗

BAD Ser128 is not phosphorylated by c-Jun NH2-terminal kinase for promoting apoptosis.

The phosphorylation and regulation of the proapoptotic Bcl-2 family protein BAD by c-Jun NH2-terminal kinase (JNK) is controversial. JNK can suppress interleukin-3 withdrawal-induced apoptosis via phosphorylation of BAD at Thr201. However, it has also been reported that JNK promotes apoptosis through phosphorylation of BAD at Ser128. Here, we report that JNK is not a BAD Ser128 kinase. JNK phosphorylates murine BAD (mBAD), but not human BAD (hBAD), in which Ser91 is equivalent to Ser128 in mBAD. In contrast, Cdc2, which phosphorylates Ser128, phosphorylates both mBAD and hBAD. Replacement of Ser128 by alanine has no effects on BAD phosphorylation by JNK in vitro and in vivo. Two-dimensional phosphopeptide mapping in combination with phosphoamino acid analysis reveals that JNK does not phosphorylate BAD at Ser128. Elimination of Ser128 phosphorylation has no effects on the proapoptotic activity of BAD in apoptosis induced by UV via JNK or growth factor withdrawal. Thus, our results show that Ser128 is not phosphorylated by JNK for promoting cell death.

Alanine↗

C-terminal amide to alcohol conversion changes the cardiovascular effects of endomorphins in anesthetized rats.

Endomorphin1-ol (Tyr-Pro-Trp-Phe-ol, EM1-ol) and endomorphin2-ol (Tyr-Pro-Phe-Phe-ol, EM2-ol), with C-terminal alcohol (-ol) containing, have been shown to exhibit higher affinity and lower intrinsic efficacy in vitro than endomorphins. In the present study, in order to investigate the alterations of systemic hemodynamic effects induced by C-terminal amide to alcohol conversion, responses to intravenous (i.v.) or intracerebroventricular (i.c.v.) injection of EM1-ol, EM2-ol and their parents were compared in the system arterial pressure (SAP) and heart rate (HR) of anesthetized rats. Both EM1-ol and EM2-ol induced dose-related decrease in SAP and HR when injected in doses of 3-100 nmol/kg, i.v. In terms of relative vasodepressor activity, it is interesting to note that EM2-ol was more potent than endomorphin2 [the dose of 25% decrease in SAP (DD25) = 6.01+/-3.19 and 13.99+/-1.56 nmol/kg, i.v., respectively] at a time when responses to EM1-ol were less potent than endomorphin1. Moreover, decreases in SAP in response to EM1-ol and EM2-ol were reduced by naloxone, atropine sulfate, L-NAME and bilateral vagotomy. It indicated that the vasodepressor responses were possibly mediated by a naloxone-sensitive, nitric oxide release, vagus-activated mechanism. It is noteworthy that i.c.v. injections of -ol derivatives produced dose-related decreases in SAP and HR, which were significantly less potent than endomorphins and were attenuated by naloxone and atropine sulfate. In summary, the results of the present study indicated that the C-terminal amide to alcohol conversion produced different effects on the vasodepressor activity of endomorphin1 and endomorphin2 and endowed EM2-ol distinctive hypotension characters in peripheral (i.v.) and central (i.c.v.) tissues. Moreover, these results provided indirect evidence that amidated C-terminus might play an important role in the regulation of the cardiovascular system.

Alcohols↗

Asymmetric glycolate aldol reactions using cinchonium phase-transfer catalysts.

Cinchona phase-transfer catalysts (PTC) were developed for glycolate aldol reactions to give differentially protected 1,2-diol products. Silyl enol ether 9 reacted to generate benzhydryl-protected products. O-Allyl trifluorobenzyl cinchonium hydrofluoride CN-4 (20 mol %) catalyzed the addition of 9 to benzaldehyde to give 8 as a single syn-product in 76% yield and 80% ee. Recrystallization enriched the product to 95% ee, and a Baeyer-Villiger reaction transformed the product into useful ester intermediates. [reaction: see text]

Journal Article↗

Effects of paeoniflorin on the cerebral infarction, behavioral and cognitive impairments at the chronic stage of transient middle cerebral artery occlusion in rats.

In the present study, the effects of paeoniflorin (PF), a characteristic monoterpene glucoside isolated from Paeoniae Radix, on cerebral infarction, neurological symptoms, tongue protrusion (TP) and performance in the water maze were examined at the chronic stage (4 weeks) of transient cerebral ischemia using a rat middle cerebral artery occlusion (MCAO) model. One-day (10 mg/kg, twice, s.c.) or seven-day (2.5-10 mg/kg, twice a day, s.c.) injection of PF significantly reduced the infarct volume as well as ameliorated the deficits in neurological symptoms caused by transient MCAO at chronic stage. Transient MCAO also induced impairments in TP and performance in the water maze. Treatment with PF was able to reverse or alleviate these impairments. These results indicate that PF may be effective for treatment of stroke.

Animals↗

A novel HBV DNA vaccine based on T cell epitopes and its potential therapeutic effect in HBV transgenic mice.

DNA vaccination represents a novel therapeutic strategy for chronic hepatitis B virus (HBV) infection. Recently, some HBV DNA vaccines have been used in the preliminary clinical trials and exhibited exciting results in chronic HBV carriers. But these vaccines only encoded the single viral antigen, the S or the PreS2/S antigen. In this study, we designed a polytope DNA vaccine encoding multiple T cell epitopes. We found that it induced stronger CTL responses than the vaccine encoding the single antigen in H-2d and H-2b mice, although the CTL response to Ld-restricted epitope suppressed the CTLs to other epitopes in H-2d-restricted mice. Interestingly, heat shock protein 70 as an adjuvant not only enhanced CTL response to the viral antigen but also overcame this epitope suppression. Furthermore, the polytope DNA vaccine resulted in a long-term down-regulation of hepatitis B virus surface antigen and inhibition of HBV DNA replication in a HBV transgenic mouse model. Therefore, our research indicates that it is practicable and feasible to design a polytope DNA vaccine for chronic hepatitis B immunotherapy.

Amino Acid Sequence↗

Alk3/Bmpr1a receptor is required for development of the atrioventricular canal into valves and annulus fibrosus.

Endocardial cushions are precursors of mature atrioventricular (AV) valves. Their formation is induced by signaling molecules originating from the AV myocardium, including bone morphogenetic proteins (BMPs). Here, we hypothesized that BMP signaling plays an important role in the AV myocardium during the maturation of AV valves from the cushions. To test our hypothesis, we used a unique Cre/lox system to target the deletion of a floxed Alk3 allele, the type IA receptor for BMPs, to cardiac myocytes of the AV canal (AVC). Lineage analysis indicated that cardiac myocytes of the AVC contributed to the tricuspid mural and posterior leaflets, the mitral septal leaflet, and the atrial border of the annulus fibrosus. When Alk3 was deleted in these cells, defects were seen in the same leaflets, ie, the tricuspid mural leaflet and mitral septal leaflet were longer, the tricuspid posterior leaflet was displaced and adherent to the ventricular wall, and the annulus fibrosus was disrupted resulting in ventricular preexcitation. The defects seen in mice with AVC-targeted deletion of Alk3 provide strong support for a role of Alk3 in human congenital heart diseases, such as Ebstein's anomaly. In conclusion, our mouse model demonstrated critical roles for Alk3 signaling in the AV myocardium during the development of AV valves and the annulus fibrosus.

Animals↗

A C-type lectin-like protein from Agkistrodon acutus venom binds to both platelet glycoprotein Ib and coagulation factor IX/factor X.

Agkisacutacin, a C-type lectin-like protein (CLP) isolated from Agkistrodon acutus venom, had been previously identified as an antagonist of platelet aggregation induced by ristocetin, as well as a certain extent fibrinogenlytic activity. In this study, agkisacutacin was further purified by three-step chromatography, and its biological functions were characterized. Agkisacutacin after further purification retained the effect on ristocetin-induced, von Willebrand factor-dependent platelet aggregation, while it lost the fibrinogenlytic activity. FACS and ELISA assays showed that agkisacutacin belongs to membrane glycoprotein Ib-binding protein (GPIb-bp) for it could block and inhibit the binding of anti-GPIb antibody to GPIb. Especially, agkisacutacin exhibits anti-coagulant activity and the function as IX/X-binding protein was confirmed by PAGE and ELISA. So, agkisacutacin is the first reported CLP that binds to both platelet membrane receptors and coagulation factors.

Agkistrodon↗

Positive association of the oxytocin receptor gene (OXTR) with autism in the Chinese Han population.

BACKGROUND: Previous research has suggested that the social impairments exhibited by individuals with autism are associated with changes in plasma oxytocin (OT) levels. The physiologic effects of oxytocin are mediated through its specific receptors (OTRs), and numerous studies have implicated OTRs in the regulation of social cognition and behavior. Animal models and linkage data from genome screens indicate that the oxytocin receptor gene (OXTR) is an excellent candidate for research concerning psychiatric disorders, particularly those involving social impairments, such as autism. METHODS: We genotyped four single nucleotide polymorphisms (SNPs) located within the OXTR gene of 195 Chinese Han autism trios, using polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: The family-based association test (FBAT) revealed a significant genetic association between autism and two of the SNPs tested (rs2254298 A: Z = 2.287, p = .0222; rs53576 A: Z = 2.573, p = .0101). When haplotypes were constructed with two, three, and four markers, the haplotype-specific FBAT revealed that a number of haplotypes, particularly those involving rs53576, were significantly associated with autism. Furthermore, haplotypes constructed with all markers showed a significant excess transmission for the specific and global haplotype analyses (p = .0020 and .0289, respectively). CONCLUSIONS: These data suggest an involvement of OXTR in the susceptibility to autism, and replication is important.

Asian People↗

Nuclear/nucleolar localization properties of C-terminal nucleocapsid protein of SARS coronavirus.

A novel coronavirus (CoV) has recently been identified as the aetiological agent of severe acute respiratory syndrome (SARS). Nucleocapsid (N) proteins of the Coronaviridae family have no discernable homology, but they share a common nucleolar-cytoplasmic distribution pattern. There are three putative nuclear localization signal (NLS) motifs present in the N. To determine the role of these putative NLSs in the intracellular localization of the SARS-CoV N, we performed a confocal microscopy analysis using rabbit anti-N antisera. In this report, we show that the wild type N was distributed mainly in the cytoplasm. The N-terminal of the N, which contains the NLS1 (aa38-44), was localized to the nucleus. The C-terminus of the N, which contains both NLS2 (aa257-265) and NLS3 (aa369-390) was localized to the cytoplasm and the nucleolus. Results derived from analysis of various deletion mutations show that the region containing amino acids 226-289 is able to mediate nucleolar localization. The deletion of two hydrophobic regions that flanked the NLS3 recovered its activity and localized to the nucleus. Furthermore, deletion of leucine rich region (220-LALLLLDRLNRL) resulted in the accumulation of N to the cytoplasm and nucleolus, and when fusing this peptide to EGFP localization was cytoplasmic, suggesting that the N may act as a shuttle protein. Differences in nuclear/nucleolar localization properties of N from other members of coronavirus family suggest a unique function for N, which may play an important role in the pathogenesis of SARS.

Animals↗

[Role of molecular screening for common fusion genes in the diagnosis and classification of leukemia].

OBJECTIVE: To assess the value of common fusion genes analysis in the diagnosis and classification of leukemia by multiplex RT-PCR. METHODS: The multiplex RT-PCR, including 8 parallel PCR reactions, could screen 86 mRNA breakpoints or splice variants at the same time, which was important for the diagnosis and prognosis of leukemia. Bone marrow samples from 161 cases of leukemia and 8 cases of myelodysplastic syndrome (MDS) were involved in the study. The distribution of common fusion genes in leukemia was analyzed by the method mentioned above in combination with clinical and morphological features. RESULTS: Ten fusion genes were detected in 115 cases of leukemia, including AML1/ETO, PML/RAR alpha, PLZF/RAR alpha, dupMLL, MLL/AF6, MLL/AF10, CBFbeta/MYH11, BCR/ABL, Hox11, and EVI1 BCR/ABL was positive in all the 52 cases of chronic myeloid leukemia; PML/RAR alpha was found in 21 of 25 acute promyelocytic leukemia (APL), and PLZF/RAR alpha was detected in one case of APL. Sixteen cases of 17 AML1/ETO-positive acute leukemia (AL) belonged to FAB-M2 subtype, and one case was mixed leukemia. Three of 4 AL cases carrying CBFbeta/MYH11 were M4 subtype, and one was M5 subtype. MLL aberrations were found in 16 AL, in which all MLL/AF6 translocation existed in M5 subtype with classic monoblastic characters. Furthermore, BCR/ABL was detected in 5 acute lymphoblastic leukemia (ALL) cases. Fusion genes were also found in 2 MDS cases, of which AML1/ETO positive-MDS-RAEB progressed to AML rapidly. CONCLUSION: Screening of common fusion genes by multiplex RT-PCR is an important tool which could provide useful and reliable molecular genetic information for the diagnosis and treatment of leukemia.

Adolescent↗