Biomedical subjects

H J Liu

Publications and source records attributed to H J Liu.

At least 37 records · Page 2Linked to original sources

PubMed2001

[A study on polymorphism of salivary esterase in personal identification].

OBJECTIVE: To research the value of polymorphism of salivary esterase(Set) in paternity and personal identification. METHODS: Phenotype and genotype of human salivary esterase were detected in 114 liquid saliva samples from the Chinese population by disc electrophoresis and fast blue RR staining assay. RESULTS: The frequency of Set type was F 22.81%, FS 50.88%, S2 6.31%. The estimated gene frequency of SetF was 0.4825 and SetS was 0.5175. The PE was 0.1875 and the DP was 0.6199. CONCLUSION: Polymorphism of salivary esterase (Set) was practical in paternity and personal identification.

Esterases↗

PubMed2000

Sesquiterpenoids and diterpenoids from the Chilean liverwort Lepicolea ochroleuca.

The ether extract of the Chilean liverwort Lepicolea ochroleuca yielded three sesquiterpenoids, ent-4 beta-Hydroxy-10 alpha-methoxyaromadendrane, ent-3 beta-Hydroxyspathulenol, and 1,10-Dioxotayloriane, as minor components. The major components were ledol and 13-epi-neoverrucosan-5 beta-ol, four other minor fusicoccanoids were identified.

Diterpenes↗

PubMed2000

The use of monoclonal antibody probes for the detection of avian reovirus antigens.

Two monoclonal antibodies (MAb), E9 and H3, prepared against avian reovirus (ARV) S1133, were used in an immuno-dot assay to detect ARV antigens from cell culture and from tendon tissue samples of chickens. The limit of viral antigens detected was 8 ng using both MAb probes. The probes detected 10 ARV isolates representing at least two serotypes or pathotypes. The results indicated that these probes had broad specificity. The probes, however, did not cross-react with viral antigens prepared from six unrelated avian viruses. The ARV antigens in tendon tissue samples were detected by both probes, and it is possible, therefore, to use either of the two MAb probes for detection of ARV infections.

Animals↗

PubMed2000

Expression and activation of caspase-3/CPP32 in CD34(+) cord blood cells is linked to apoptosis after growth factor withdrawal.

Caspase-3/CPP32, a member of the interleukin-1 converting enzyme (ICE) family, is considered an executioner protease in mammalian cells during apoptosis. Although expression and activation of caspase-3/CPP32 protein have been studied in many tissues and leukemia cell lines, this has not been explored in primitive hematopoietic CD34(+) cells. In this study, we evaluated expression and activation of caspase-3/CPP32 protein in CD34(+) cells from cord blood (CB) during apoptosis induced by growth factor deprivation. Reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, and flow cytometry analysis were used in this study to determine the expression of caspase-3/CPP32 in CD34(+) CB cells during apoptosis. Our results demonstrated that caspase-3/CPP32 mRNA was constitutively expressed at a very low level in freshly isolated CD34(+) cells. Expression of caspase-3/CPP32 mRNA and protein was upregulated when these cells were first expanded in suspension culture with growth factors for 3 days. However, only the 32 kDa inactive caspase-3/CPP32 proenzyme was detected in the freshly isolated CD34(+) cells and after 3 days expansion with cytokines. Within 12 hours after growth factor withdrawal from expanded cells caspase-3/CPP32 was activated and a cleavage 20 kDa protein was detected; a poly(ADP-ribose) polymerase (PARP) was cleaved by activated caspase-3/CPP32. Activation of caspase-3/CPP32 and apoptosis upon growth factor withdrawal were inhibited/reduced by the caspase inhibitors, z-VAD-fmk and DEVD-CHO. These results demonstrate that caspase-3/CPP32 is involved in apoptosis of primitive CB CD34(+) cells but may not be the only mechanism involved.

Antigens, CD34↗

PubMed2000

Tissue print hybridisation and reverse transcriptase PCR in the detection of infectious bursal disease viruses in bursal tissues.

The genome segments of infectious bursal disease viruses (IBDV) in the bursa of Fabricius from experimently infected chickens or field samples were detected by tissue print hybridization (TPH) with subsequent reverse transcriptase (RT)- polymerase chain reaction (PCR). Bursae were imprinted onto nylon membrane and then hybridized with a cloned digoxigenin (DIG)-labeled cDNA probe. Tissue prints on nylon membrane were readily distinguished from control prints by color development and differences in signal intensity. In order to verify the TPH test, RT - PCR was used to amplify a 643-base pair fragment on the VP 2 gene of IBDV in the bursa of Fabricius. With all isolates, a c DNA fragment of 643 bp long was generated as expected and further confirmed the specificity of TPH. Our results suggest that a large number of field samples or selected tissues can be rapidly examined by TPH technique when combined with a cloned DIG -labeled c DNA probe.

Animals↗

PubMed2000

Suppressive effects of TNF-alpha, TGF-beta1, and chemokines on megakaryocytic colony formation in CD34+ cells derived from umbilical cord blood compared with mobilized peripheral blood and bone marrow.

CD34+ cells from human umbilical cord blood (CB) were isolated and investigated for megakaryocytic (MK) colony formation in response to recombinant human (rh) stimulatory and suppressive cytokines and compared with their counterparts in normal BM and G-CSF-mobilized peripheral blood (mPBL). First, we observed that IL-11 by itself at any dosage had no stimulator activity on MK colony formation derived from CD34+ cells in CB, mPBL, and BM. IL-3, steel factor (SLF), or thrombopoietin (Tpo) alone stimulated numbers of colony-forming unit-megakaryocyte (CFU-MK) in a dose-dependent fashion. Maximum growth of MK progenitor cells was noted in the presence of a combination of cytokines: IL-11, IL-3, SLF, and Tpo. The frequency of CFU-MK in CB and mPBL was significantly greater than that in BM, and the size of colonies in CB and mPBL was significantly greater than that in BM, and the size of colonies was larger as well. In addition, an increased number of big mixed colonies containing MK were observed in CB and mPBL. In the presence of IL-11, IL-3, SLF, and Tpo, CFU-MK derived from CB, mPBL, and BM was suppressed by tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1). CFU-MK derived from normal BM was inhibited by some chemokines evaluated, whereas CFU-MK derived from CB was suppressed only by platelet factor-4 (PF-4), IFN-inducible protein-10 (IP-10), Exodus-1, Exodus-2, and Exodus-3, but to a lesser degree. In CB, unlike granulocyte-macrophage (CFU-GM), erythroid (BFU-E), high-proliferative potential (HPP-CFC), or multipotential (CFU-GEMM) progenitors, at least a subpopulation of MK progenitors are in S-phase. Therefore, CB MK progenitors respond to the suppressive effects of some members of the chemokine family. Similar results were noted for burst-forming unit-MK (BFU-MK). Our results indicate that CB and mPBL are rich sources of MK progenitors and that MK progenitors in CB are responsive to the suppressive effects of TNF-alpha and TGF-beta1 and some members of the chemokine family.

Antigens, CD34↗

PubMed2000

Vasopressin and PGE(2) regulate activity of apical 70 pS K(+) channel in thick ascending limb of rat kidney.

Vasopressin and prostaglandin E(2) (PGE(2)) are involved in regulating NaCl reabsorption in the thick ascending limb (TAL) of the rat kidney. In the present study, we used the patch-clamp technique to study the effects of vasopressin and PGE(2) on the apical 70 pS K(+) channel in the rat TAL. Addition of vasopressin increased the channel activity, defined as NP(o), from 1.11 to 1.52 (200 pM) and 1.80 (500 pM), respectively. The effect of vasopressin can be mimicked by either forskolin (1-5 microM) or 8-bromo-cAMP/dibutyryl-cAMP (8-Br-cAMP/DBcAMP) (200-500 microM). Moreover, the effects of cAMP and vasopressin were not additive and application of 10 microM H-89 abolished the effect of vasopressin. This suggests that the effect of vasopressin is mediated by a cAMP-dependent pathway. Applying 10 nM PGE(2) alone had no significant effect on the channel activity. However, PGE(2) (10 nM) abolished the stimulatory effect of vasopressin. The PGE(2)-induced inhibition of the vasopressin effect was the result of decreasing cAMP production because addition of 200 microM 8-Br-cAMP/DBcAMP reversed the PGE(2)-induced inhibition. In addition to antagonizing the vasopressin effect, high concentrations of PGE(2) reduced channel activity in the absence of vasopressin by 33% (500 nM) and 51% (1 microM), respectively. The inhibitory effect of high concentrations of PGE(2) was not the result of decreasing cAMP production because adding the membrane-permeant cAMP analog failed to restore the channel activity. In contrast, inhibiting protein kinase C (PKC) with calphostin C (100 nM) abolished the effect of 1 microM PGE(2). We conclude that PGE(2) inhibits apical K(+) channels by two mechanisms: 1) low concentrations of PGE(2) attenuate the vasopressin-induced stimulation mainly by reducing cAMP generation, and 2) high concentrations of PGE(2) inhibit the channel activity by a PKC-dependent pathway.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2000

Detection of hepatitis C virus RNA sequences in B-cell non-Hodgkin lymphoma.

Serologic testing shows that hepatitis C virus (HCV) may have a role in the pathogenesis of B-cell non-Hodgkin lymphomas (B-cell NHLs). We tried to demonstrate HCV RNA sequences in paraffin-embedded tissue from B-cell NHLs by reverse-transcription double polymerase chain reaction (RT-PCR) and Southern blotting. We studied 31 consecutive cases of B-cell NHLs; lymph nodes from 32 patients with diseases other than B-cell NHL were negative controls. Positive-strand HCV RNA was tested with primers for the 5' untranslated region. Replicative negative strand HCV RNA was tested with strand-specific RT-PCR for the 5' untranslated region. Immunohistochemical staining for HCV was done using an antibody to HCV core protein. Positive-strand HCV RNA was detected in 8 patients with B-cell NHL; negative-strand HCV RNA was detected in 6 of these cases, indicating viral replication. All control cases were negative for HCV RNA. Immunohistochemistry showed no staining of lymphoma cells for HCV core proteins in any case. HCV and B-cell NHLs may be associated. RT-PCR on paraffin-embedded lymphoma tissue is an alternative method of testing for HCV. The value of immunohistochemistry could not be ascertained. The exact role of HCV in the pathogenesis of B-cell NHL needs to be studied further.

Adolescent↗

PubMed2000

Abdominal wall necrosis following transcatheter arterial chemoembolization for hepatocellular carcinoma.

A 76-year-old man, who had inoperable hepatocellular carcinoma, had been treated with transcatheter arterial chemoembolization (TACE) 11 times, percutaneous ethanol injection therapy three times and conformal radiotherapy once, all in other hospitals. At this admission, he developed myocutaneous necrosis in the right abdominal wall after TACE, via the collateral of the right internal mammary artery (IMA). Necrosis of the abdominal wall was due to ischemic changes caused by embolization of the distal branches of the IMA, which were aggravated by previous radiation therapy. We advise that embolization of the IMA in patients who have received radiotherapy should be avoided, if possible.

Abdominal Muscles↗

PubMed2000

[A study of apoptosis and related gene bcl-2 and p53 expression in hippocampus of rats exposed to repeated +Gz].

Objective. To investigate the role of apoptosis in mechanisms of brain damage induced by +Gz exposures. Method. Twenty conscious SD rats were randomly divided into 5 groups. Rats in the control group (n=4) were exposed to +1 Gz and rats in the 4 experimental groups (n=16) were exposed to +14 Gz for three times, each for 45 seconds with 30 min interval in between. All the +Gz exposured were on an animal centrifuge. The rat brains were taken 30 min, 6 h, 24 h and 48 h after the last centrifuge run and fixed and embedded. The apoptosis and expression changes of related gene bcl-2 and p53 were detected by terminal deoxynucleotide (correction of deoxynuleotide) transferase-mediated dUTP nick end labeling (TUNEL) technique and immunohistochemical method, respectively. Result. Apoptotic cells and expression changes of bcl-2 and p53 were observed in CA1 subregion of rat hippocampus taken 6 h after repeated +Gz exposures, but returned to normal after 24-48 h. Conclusion. It suggests that apoptosis and expression changes of bcl-2 and p53 in rats hippocampus can be induced by repeated +Gz exposures and the apoptosis is one of the molecular mechanisms of brain damage induced by repeated +Gz exposures.

Animals↗

PubMed2000

[Changes of mRNA expression of IL-1beta and TNF-alpha in rat brains after repeated exposures to +Gz].

Objective. To study changes of mRNA expression of IL-1beta and TNF-alpha in rat brains after repeated exposures to +Gz. Method. Twenty conscious SD rats served as the subjects. They were randomly divided into 5 groups. Using an animal centrifuge, control rats (n = 4) were exposed to +1 Gz and experimental rats (n = 16) were exposed to +14 Gz three times, each for 45 s with 30 min interval in between. The rat brains were taken 30 min, 6 h, 24 h and 48 h after the last centrifuge run and total RNA was isolated. mRNA expression levels of IL-1beta and TNF-alpha in rat brain were measured by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Result. mRNA expression levels of IL-1beta and TNF-alpha in rat brains taken 30 min, 6 h and 24 h after repeated +Gz exposures were significantly higher than those in control rats, but returned to normal after 48 h. Conclusion. It suggested that mRNA expressions of IL-1beta and TNF-alpha in rat brains can be stimulated by repeated +Gz exposures and the increased expression of IL-1beta and TNF-alpha may play a role in the pathologic course of brain damage induced by +Gz exposures, but the damage is reversible.

Acceleration↗

PubMed1999

Structure and genomic organization of porcine RACK1 gene.

The cDNA encoding porcine RACK1 protein was isolated from porcine spleen cDNA library. The deduced protein sequence of porcine RACK1 cDNA shows that it contains 317 amino acid residues, and shares nearly 100% identity with its vertebrate counterparts. Noticeably, the RACK1 protein was differentially expressed in various porcine tissues. High expression of RACK1 protein was observed in the tissues including thymus, pituitary, spleen and liver, whereas there was no detectable expression in muscle. The genomic DNA of porcine RACK1 with approximate 7.5 kb was constructed by both polymerase chain reaction amplification and genomic library screening. It consists of eight exons intervened by seven introns, and most of the intron/exon splice sites conform to the GT/AG rule. The promoter region contains functional serum response element, YY1-like binding site and AP1 site, which is supported by the finding that the expression of RACK1 gene in cultured porcine ST cells has a serum response as well as a TPA response.

Amino Acid Sequence↗

PubMed1999

Effects of L-glutamic acid on acid secretion and mucosal blood flow in the rat stomach.

The effect of intravenous administration of L-glutamic acid (L-Glu) on gastric acid secretion and gastric mucosal blood flow (GMBF) in anesthetized rats were investigated. Infusion with synthetic L-Glu alone had no effect on spontaneous acid secretion. However, L-Glu reduced histamine- (2 mg/kg/hr) or oxotremorine- (1 microg/kg/hr) stimulated acid secretion, whereas L-Glu had no effect on acid secretion induced by pentagastrin (8 microg/kg/hr). Furthermore, this inhibitory effect of L-Glu on histamine- or oxotremorine-stimulated acid secretion was blocked by 6,7-dinitroquinoxaline-2,3-dione (DNQX), a non-NMDA receptor antagonist. The effect of L-Glu on gastric mucosal microcirculation in the anesthetized rats was evaluated by using Laser Doppler Flowmetry (LDF). The results showed that L-Glu did not significantly reduce both mucosal and serosal blood flow in stomach. No significant modulatory effect on histamine- or oxotremorine-stimulated increase in GMBF was noted after infusion with L-Glu. It is concluded that L-glutamic acid is capable of the modulating of gastric acid secretion via ionotropic non-NMDA receptors, but do not affect on GMBF. However, L-glutamic acid showed no effect on acid secretion by itself.

Anesthesia↗

PubMed1999

Phylogenetic characterization of novel transport protein families revealed by genome analyses.

As a result of recent genome sequencing projects as well as detailed biochemical, molecular genetic and physiological experimentation on representative transport proteins, we have come to realize that all organisms possess an extensive but limited array of transport protein types that allow the uptake of nutrients and excretion of toxic substances. These proteins fall into phylogenetic families that presumably reflect their evolutionary histories. Some of these families are restricted to a single phylogenetic group of organisms and may have arisen recently in evolutionary time while others are found ubiquitously and may be ancient. In this study we conduct systematic phylogenetic analyses of 26 families of transport systems that either had not been characterized previously or were in need of updating. Among the families analyzed are some that are bacterial-specific, others that are eukaryotic-specific, and others that are ubiquitous. They can function by either a channel-type or a carrier-type mechanism, and in the latter case, they are frequently energized by coupling solute transport to the flux of an ion down its electrochemical gradient. We tabulate the currently sequenced members of the 26 families analyzed, describe the properties of these families, and present partial multiple alignments, signature sequences and phylogenetic trees for them all.

Amino Acid Sequence↗

PubMed1999

Comparison of two molecular techniques for the detection of avian reoviruses in formalin-fixed, paraffin-embedded chicken tissues.

Reverse transcription (RT) in situ polymerase chain reaction (PCR) and in situ hybridization (ISH) techniques were used to detect the sigma c-encoded gene of avian reovirus (ARV) in chicken tissue sections. The advantage of using in situ methods is to make more rapid and accurate diagnosis of ARV infections. The sensitivity of these two techniques were compared. Of the two techniques, the RT in situ PCR test was found to be more sensitive than ISH and provided the rapid, sensitive, and specific detection of ARV infections.

Animals↗

PubMed1999

Identification of the sigma C-encoded gene of avian reovirus by nested PCR and restriction endonuclease analysis.

A nested reverse transcription (RT)-polymerase chain reaction with subsequent restriction endonuclease analysis was developed for identification of the sigma C-encoded gene of avian reoviruses (ARV). PCR products derived from the sigma C-encoded gene of all tested ARVs resulted in a specific DNA band of 1023 bp, indicating that there were no apparent insertions or deletions in this region. Amplification with the nested primer pairs S1M-S1N and S1P-S1N generated 330 and 239 bp, respectively. PCR products amplified from the sigma C-encoded of all tested ARVs isolates were further confirmed by Southern blot hybridization and restriction endonuclease analysis. PCR amplified cDNA fragment (1023 bp) cleaved with Pst I generated two fragments of 565 and 458 bp. The amplified sigma C-encoded gene of ARV was subcloned into PQE 32 vector for further study of its antigenicity and immunogenicity. The sensitivity of RT-PCR was examined on nucleic acids from the ARV infected cell cultures. The detection limit was 10(0) to 10(-1) TCID50 of ARV in a ethidium bromide stained gel and could be increased further to 10(-1) to 10(-2) TCID50 of ARV by Southern blot hybridization using a digoxigenin-labeled cDNA probe. The sensitivity increased approximately 10(3) to 10(4) folds when the cDNA was reamplified with two sets of nested primers.

Animals↗

PubMed1999

Neopallavicinin from the Taiwanese liverwort Pallavicinia subciliata.

Neopallavicinin (2), a diastereomer of pallavicinin (1), was identified from the Taiwanese liverwort Pallavicinia subciliata. The structure of neopallavicinin was deduced by spectroscopic analysis. Three chemotypes may be classified for the species Pallavicinia subciliata.

Diterpenes↗

PubMed1999

Expression of HSP70 gene in rat brain after exposures to repeated +Gz.

OBJECTIVE: To study the changes of mRNA expression of heat shock protein 70 (HSP70) in the rat brain exposed to repeated +Gz. METHOD: The mRNA expression levels of HSP70 in rat brain were measured by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). RESULT: The HSP70 mRNA expression levels in rat brains taken 30 min and 6 h after repeated +Gz exposures were significantly higher than those in control group, while the difference between the levels of control group and those of experimental rat brains taken 24 h after +Gz exposure was not significant. CONCLUSION: It is suggested that HSP70 mRNA expression in rat brain can be induced by repeated +Gz exposures and the increased HSP70 mRNA expression may play an important role in self-protection against brain damage induced by +Gz exposures.

Animals↗