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Biomedical subjects

H J Liu

Publications and source records attributed to H J Liu.

At least 73 records · Page 4Linked to original sources
PubMed1995

Molecular diagnosis of thalassemia in Taiwan.

Thalassemia is an autosomal recessive disease characterized by absent or decreased synthesis of the globin chain. This disease is very common in Taiwan area. It mainly consists of alpha- and beta-thalassemia. The diagnosis of these entities depends on hemoglobin electrophoresis, mean corpuscular volume (MCV), or mean hemoglobin concentration of red blood cell and excludes the disease of iron deficiency anemia. However, these tests are not reliable. The definite diagnosis is to check the hemoglobin genes directly. In recent years, we have developed several molecular techniques to solve these problems. This review focuses on the techniques which are used recently in Taiwan area.

Female↗
PubMed1994

Detection of genetic variations in serotype I isolates of infectious bursal disease virus using polymerase chain reaction and restriction endonuclease analysis.

Reverse transcription with polymerase chain reaction (PCR) followed by restriction endonuclease analysis detected genetic variations among serotype I isolates of infectious bursal disease virus (IBDV). Using a set of synthetic primers derived from the large genome segment of APHIS-IBDV, the hypervariable region (AccI-SpeI fragment) located in the VP2 gene was amplified. With all strains, a cDNA fragment of approximately 643 bp was amplified, indicating that there were no apparent deletions or insertions in this region among isolates. Fragments amplified from 9 isolates were digested with 14 restriction enzymes. Restriction fragment profiles generated by restriction enzymes NaeI, StuI, TaqI, and SacI, showed genetic variations among isolates. This study provided a simple and sensitive method for detection of genetic variations among isolates that are closely related serologically and could not be differentiated using current serologic methods.

Animals↗
PubMed1993

Involvement of alpha- and beta-adrenoceptors in antinociception at the lumber spinal level in mice.

To study the role of the adrenergic receptors in the regulation of nociceptive transmission in male albino mice, the antinociceptive activity of adrenergic drugs was tested with a tail-flick method. Subarachnoid infusion of phenylephrine and clonidine into T13-L1 of spinal cord produced a dose-dependent elevation of the nociceptive threshold in sodium pentobarbital anesthetized mice. The inhibitory effect of alpha-adrenoceptor agonists was antagonized by pretreatment with alpha-adrenoceptor antagonists. Isoproterenol also increased the nociceptive threshold significantly. The antinociceptive effect of isoproterenol was reversed by pretreatment with beta antagonist, propranolol. These findings suggest that spinal adrenergic receptors of both alpha and beta types probably are involved in the inhibition of nociceptive transmission.

Analgesia↗
PubMed1992

Solubilization and purification of the prostaglandin E2 receptor from cardiac sarcolemma.

A prostaglandin E2 (PGE2) receptor was solubilized and isolated from cardiac sarcolemma membranes. Its binding characteristics are almost identical to those of the membrane bound receptor. [3H]PGE2 binding to solubilized and membrane bound receptor was sensitive to elevated temperature and no binding was observed in the absence of NaCl. No significant effects of DTT, ATP, Mg2+, Ca2+ or of changes in buffer pH were observed on [3H]PGE2 binding to either solubilized or membrane-bound receptor. Unlabelled PGE1 displaced over 90% of [3H]PGE2 from the CHAPS-solubilized receptor. PGD2, PGI2, PGF2 alpha and 6-keto-PGF1 alpha were not effective in displacing [3H]PGE2 from the receptor. Scatchard analysis of [3H]PGE2 binding to CHAPS-solubilized receptor revealed the presence of two types of PGE2 binding sites with Kd of 0.33 +/- 0.05 nM and 3.00 +/- 0.27 nM and Bmax of 0.5 +/- 0.04 and 2.0 +/- 0.1 pmol/mg of protein. The functional PGE2 receptor was isolated from CHAPS-solubilized SL membrane using two independent methods: first by a WGA-Sepharose chromatography and second by sucrose gradient density centrifugation. Receptor isolated by these two methods bound [3H]PGE2. Unlabelled PGE1 and PGE2 displaced [3H]PGE2 from the purified receptor. Scatchard analysis of [3H]PGE2 binding to purified receptor revealed the presence of the two binding sites as observed for the membrane bound and CHAPS-solubilized receptor. SDS-polyacrylamide gel electrophoresis of the purified receptor fractions revealed the presence of a protein band of M(r) of approx. 100,000. This 100-kDa was photolabelled with [3H]azido-PGE2, a photoactive derivative of PGE2. We propose that this 100-kDa protein is a cardiac PGE2 receptor.

Affinity Labels↗
PubMed1992

The recognition of DNA cleavage sites by porcine spleen topoisomerase II.

The cutting sites specificity of topoisomerase II from porcine spleen were determined by a modified Sanger's DNA sequencing method. The topoisomerase II prefers to cut DNA at the 3' side of A and leave 5' protruding end with two staggering bases. Through the free energy analysis for DNA duplex, we also found that the topoisomerase II seemed cut DNA preferably at energetically unstable regions. So it is concluded that the specific DNA cutting by porcine spleen topoisomerase II has two structural recognition factors: one is to localize around the energetically unstable region and another is to act at the 3' side of A base.

Animals↗
PubMed1992

Mechanisms of adrenaline-induced antinociception in mice.

Infusion of adrenaline into the upper lumbar subarachnoid space in lightly anesthetized mice produced a significant elevation of the nociceptive threshold as quantitated by tail flick test. The antinociceptive effect of adrenaline was dose-dependent and antagonized equally by pretreatment with either alpha-1 selective antagonist prazosin or alpha-2 selective antagonist yohimbine at a dose of 0.05 microgram/5 microliter/mouse. This antinociceptive effect of adrenaline was also blocked by pretreatment with beta antagonist propranolol or opiate antagonist naloxone at higher doses, i.e., 0.5 microgram and 1.0 microgram/5 microliter/mouse, respectively. These results suggest that the antinociceptive mechanisms of adrenaline at the lumbar spinal level in the mouse seem to be mediated not only through alpha- and beta-adrenergic pathways but also through opiate system.

Analgesics↗
PubMed1992

Surgical management of an unusual osteomyelitis involving posterior elements in lumbar spine. A case report.

Improper and invasive management of low back pain may lead to an unexpected tragedy, vertebral osteomyelitis. A 30-year-old female patient suffering from low back pain after a lumbar strain called on a herbal therapist and was given a herb massage with some unknown medication. Unfortunately, a persistent painful ulcer with discharge developed over her back. She was referred to our clinic shortly after where x-ray showed bony destruction over the spinous process, facet, and lamina of L4. Fistulectomy, debridement and spinal fusion were performed. A satisfactory outcome was finally achieved.

Adult↗
PubMed1992

Effects of intra-raphe injection of amino acids on cardiovascular function in rats.

The effects of microinjection of an excitatory amino acid (glutamate, 10 micrograms) or several inhibitory amino acids (taurine 10 micrograms, GABA 10 ug or glycine 10 ug) into the dorsal raphe region on cardiovascular function were assessed in rats under pentobarbital sodium. Intra-raphe administration of glutamate, but not saline, caused an increase in the mean arterial pressure. By contrast, intra-raphe administration of taurine, GABA or glycine, but not saline, caused a decrease in both the mean arterial pressure and the heart rate. The glutamate-induced hypertension or both the hypotension and the bradycardia induced by taurine, GABA or glycine was antagonized by pretreatment with intra-raphe injection of a serotonergic receptor antagonist (1 ug cyproheptadine). In addition, the vasopressor and bradycardia responses to an intravenous dose of epinephrine (2.5 ug/kg) were assessed in saline-treated rats and amino acid-treated rats. Intra-raphe injection of glutamate produced a significant decrease in reflex bradycardia compared to the controls. On the other hand, administration of taurine, GABA or glycine into the dorsal raphe region led to an enhancement of epinephrine-induced bradycardia. Again, the reduction or the facilitation of the epinephrine-induced bradycardia following administration of these amino acids was antagonized by pretreatment with cyproheptadine. The results suggest that the serotonergic receptor mechanisms in the dorsal raphe region play a role in the elaboration or modulation of the cardiovascular responses to amino acids (including glutamate, taurine, GABA and glycine).

Amino Acids↗
PubMed1991

Induction of heat-shock response and alterations of protein phosphorylation by a novel topoisomerase II inhibitor, withangulatin A, in 9L rat brain tumor cells.

Withangulatin A is a newly identified in vitro topoisomerase II inhibitor isolated from the Chinese antitumor herb Physalis angulata. In vivo, it was found to be cytotoxic, capable of suppressing general protein synthesis and of inducing the synthesis of a small set of proteins including those generated by heat-shock treatment. The 70 kDa protein generated by withangulatin A was unequivocally identified as the heat-shock protein 70 (HSP70) since both proteins migrated to the same position on two-dimensional polyacrylamide gels, could be recognized by a monoclonal antibody to human HSP70, and exhibited identical peptide maps. The induction of protein synthesis by withangulatin A was regulated at the transcriptional level since it was aborted in cells pre-treated with actinomycin D. However, the initiation of this process did not require de novo protein synthesis since it was not affected by cycloheximide. Other cellular effect of withangulatin A was alterations of protein phosphorylation including an enhancement of phosphorylation of a 65 kDa protein which was also detected in the heat-shocked cells. Moreover, this process was observed within 7.5 min after the initial heat treatment which is much faster than the onset of HSP synthesis. Therefore, increased phosphorylation of the 65 kDa protein may represent one of the earliest signals generated by both heat-shock and withangluatin A and may be involved in the upstream regulation of heat-shock response in cells.

Animals↗
PubMed1991

Effects of ginsenoside Rb1 on central cholinergic metabolism.

Ginsenosides, the saponins of ginseng, are bioactive ingredients which exert many beneficial effects. One ginsenoside, Rb1, extracted from North American ginseng (Panax quinquefolium L.), partially prevents the memory deficits induced by a cholinergic agent (scopolamine) in rats. In vitro studies show that Rb1 has no effect on quinuclidinyl benzylate binding or on acetylcholinesterase activity, but facilitates the release of acetylcholine (ACh) from hippocampal slices. The increase in ACh release is associated with an increased uptake of choline into nerve endings; however, calcium influx is unaltered. The ability of Rb1 to prevent memory deficits may be related to facilitation of ACh metabolism in the central nervous system.

Acetylcholine↗
PubMed1991

[Determination of ionization constants of primaquine and study of its coordination ratio with vitamin C].

Primaquine (P) has long been used as an antimalarial drug. The following formulas are derived for determination of the ionization constants of PH3+3 by pH-titration method: Ka1 = [aH + (3 - a)Cp]/[(a - 2)Cp/aH - 1] Ka3 = [(1 - a)Cp aH - Kw]/(a Cp + Kw/aH) = (1/Ka2)[(2 - a)Cp a2H - Kw aH]/(Kw/aH + a Cp) + [(1 - a) Cp aH - Kw]/(Kw/aH + a Cp) in which Kw is the ionic product of water, a is the mole ratio of HClO4 to primaquine and Cp is the total concentration of primaquine. The ionization constants of primaquine in 50% (v/v) ethanol in water determined at 25 degrees C in the ionic strength range of 5 x 10(-3)-5 x 10(-2) mol/L are: Ka1 = (3.84 +/- 2.35) x 10(-2) (attributed to the secondary ammonium group of primaquine); Ka2 = (1.50 +/- 1.17) x 10(-8) (attributed to the tertiary ammonium group); Ka3 = (2.07 +/- 0.27) x 10(-10) (attributed to the primary ammonium group). The coordination ratio of primaquine to vitamin C in the above solvent is determined by continuous variation and mole ratio methods based on pH and conductance measurements to be 1:1, indicating that the coordination compound formed in the solution is mainly a 1:1 compound.

Ascorbic Acid↗
PubMed1990

Photolabelling of the prostaglandin E2 receptor in cardiac sarcolemmal vesicles.

A [3H]azidophenacyl ester of PGE2 ([3H]azido-PGE2) was synthesized and used to photoaffinity label the protein component of the high affinity PGE2 binding site in cardiac sarcolemma membrane. Photolysis of the isolated cardiac sarcolemmal vesicles in the presence of [3H]azido-PGE2 resulted in the covalent labelling of a protein component that migrated on sodium dodecyl sulfate-polyacrylamide gels with an apparent molecular weight of 100,000. Incorporation of the [3H]azido-PGE2 did not occur in the absence of photolysis. The photolabelling of the 100-kDa protein by [3H]azido-PGE2 was inhibited by excess unlabelled PGE2 and azido-PGE2. Specific binding of [3H]azido-PGE2 was displaced by excess unlabelled PGE2 or azido-PGE2, but not PGF2 alpha, 6-keto-PGF1 alpha or PGD2. These results indicate that the 100-kDa photoaffinity labelled [3H]azido-PGE2 binding protein contains the binding site for PGE2 in isolated cardiac sarcolemma membranes.

Affinity Labels↗
PubMed1990

[Studies on streptomycin albumin microspheres for injection].

Streptomycin albumin microspheres were prepared by polymeric dispersing agents. Some physical properties including the size, distribution and surface state of the microspheres were determined. The results showed that the diameter of the microspheres ranged from 10 to 30 microns and the content was 20.3 +/- 0.5%. Drug release from the microspheres was performed by a dynamic dialysis system. Tissue distribution of streptomycin albumin microspheres in rats was studied by both fluorescein isothiocyanate and 125I labelled microspheres. The experiments revealed that the major part of the microspheres accumulated in the lung following intravenous injection. The effectiveness and side effects of the streptomycin in the microspheres remain to be determined.

Albumins↗
PubMed1989

Depletion of hypothalamic norepinephrine reduces the fever induced by polyriboinosinic acid: polyribocytidylic acid (Poly I:Poly C) in rats.

Administration of either Poly I:Poly C (0.05-0.50 micrograms) or norepinephrine (2-8 micrograms) into the anterior hypothalamic area produced a dose-related fever in rats. The fever induced by Poly I:Poly C was attenuated after selective depletion of norepinephrine in the hypothalamus. However, selective depletion of hypothalamic norepinephrine did not affect the fever induced by intrahypothalamic norepinephrine. The data indicate that Poly I:Poly C may act to induce fever through the endogenous release of norepinephrine from the rat's hypothalamus.

Animals↗
PubMed1989

[Protective effects of the pollen of Codonopsis pilosula (Franch.) Nannf. on liver lesions at the ultrastructural level].

The experimental hepatic lesion of C57 mice was induced by carbon tetrachloride (CCI4), and the feeds containing pollen of Codonopsis pilosula were given to the animals. It was found by electronic microscopy that these pollens evidently reduced the hepatic steatosis, improved liver necrosis, suppressed the formation of the collagen fibrils in Disse's spaces and around central veinules. It was shown that the pollens of Codonopsis pilosula could counteract efficiently the liver lesion of mice induced by CCI4.

Animals↗
PubMed1988

Bile salt binding properties of commonly used gastrointestinal drugs: maalox, carafate, and questran.

We have validated a method to measure bile salt binding by Maalox (aluminum hydroxide and magnesium hydroxide), Carafate (sucralfate), and Questran (cholestyramine) in vitro. The method used in this study involves a correction for adherent water volume and thus provides a correct measure of bile salt binding. With this approach, we described the binding properties of Maalox, Carafate, and Questran. The bile salt binding capacities of Carafate and Maalox are limited and do not have physiological or pharmacological significance. On the other hand, we found that Questran has substantial bile salt binding capacity. At the recommended dosage, Questran could deplete the total bile salt pool. We also found that Carafate, although not used as an antacid, has buffering capacity (maintaining a pH of solution in the range 4.2-4.8) which might contribute to its effectiveness as an ulcer treatment drug.

Aluminum Hydroxide↗
PubMed1988

Phosalone applied to cotton (Gossypium hirsutum L.): its deposition and persistence on foliages, soils and final residues in seeds.

Phosalone, O,O-diethyl-S-(6-chloro-1,3-benzoxazol-2(3H)-onyl)methyl phosphorodithioate, was field-applied by ground equipment to cotton (Gossypium hirsutum L.) at the rates of 1050 and 2100 g a.i./ha, respectively, to determine its dissipation on leaves and soils and the residues in seeds at harvest. The insecticide concentrations on cotton leaves and soils were measured periodically for 14 days following its application. It was found that the half lives of the insecticide on cotton leaves at the dosages of 1050 and 2100 g a.i./ha were 6.8 and 6.3 days, respectively. And the half lives on soils for the 2 dosages were 7 and 5.8 days, respectively. The residues remaining in soils at harvest time were 0.072 and 0.121 mg/kg 14 days post-application and the residues in cotton seeds were relatively low (less than 0.02-0.12 mg/kg).

Gossypium↗