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Biomedical subjects

E H Liu

Publications and source records attributed to E H Liu.

At least 37 records · Page 2Linked to original sources
PubMed1999

F4-isoprostanes as specific marker of docosahexaenoic acid peroxidation in Alzheimer's disease.

F2-isoprostanes are prostaglandin-like compounds derived from free radical-catalysed peroxidation of arachidonic acid. Peroxidation of eicosapentaenoic acid produces F3-isoprostanes, whereas peroxidation of docosahexaenoic acid would give F4-isoprostanes. This study demonstrates the presence of esterified F4-isoprostanes in human brain and shows that levels are elevated in certain brain cortex regions in Alzheimer's disease. Our data with Alzheimer's disease suggest that analysis of F4-isoprostanes will provide new opportunities to study lipid peroxidation in the neurodegenerative diseases.

Alzheimer Disease↗
PubMed1999

Sevoflurane anaesthesia with an Oxford Miniature Vaporizer in vaporizer inside circle mode.

Anaesthesia was induced and maintained successfully with sevoflurane using an Oxford Miniature Vaporizer (OMV) in vaporizer inside circle (VIC) mode. With continuous monitoring using the Drager Narkomed 4 machine agent analyser, the expired sevoflurane concentration was monitored and controlled easily. During induction, there was no cardiovascular depression, apnoea or coughing, but involuntary movements and breath-holding were common.

Adult↗
PubMed1999

Anaesthetic management of patients undergoing lung volume reduction surgery for treatment of severe emphysema.

Lung volume reduction surgery can improve lung function in patients with emphysema. We report our anaesthetic experience, problems and the physiological data of eight patients. Our aims were prevention of air trapping and air leaks, good analgesia and early recovery and mobilization. We were able to achieve these aims using pressure limited ventilation, lumbar epidural diamorphine, propofol infusions and intensive physiotherapy. Hypoxia during one-lung ventilation was the main intraoperative problem. Air leaks, infection and pulmonary hypertension were the main postoperative problems.

Anesthesia↗
PubMed1999

Negative pressure pulmonary oedema caused by biting and endotracheal tube occlusion--a case for oropharyngeal airways.

A patient had general anaesthesia for laparoscopic surgery. She bit on and occluded her endotracheal tube during recovery from anaesthesia. Strong inspiratory efforts during airway obstruction caused negative pressure pulmonary oedema. The pulmonary oedema resolved within 24 hours. Use of an oropharyngeal airway as a bite block could have prevented this complication.

Adult↗
PubMed1998

F4-isoprostanes: a novel class of prostanoids formed during peroxidation of docosahexaenoic acid (DHA).

Isoprostanes are prostaglandin (PG)-like compounds derived from free radical-catalyzed peroxidation of polyunsaturated fatty acids. F2-isoprostanes are produced in vivo by a non-cyclooxygenase mechanism involving free radical peroxidation of arachidonic acid. Peroxidation of eicosapentaenoic acid produces F3-isoprostanes. In this study, we explore the possibility of formation of F4-isoprostanes during peroxidation of docosahexaenoic acid (DHA) in vitro. DHA-liposomes were exposed at 37 degrees C to either 2,2'-azobis-(2-amidinopropane) hydrochloride (AAPH) or copper ions at final concentrations of 10 mM and 50 microM, respectively. Sample processing involved solid-phase extraction on a C18 and an NH2- cartridge. After conversion to pentafluorobenzyl ester and trimethylsilyl derivatives, F4-isoprostanes were analysed by negative ion-chemical ionisation mass spectrometry using tetradeuterated PGF2 alpha (PGF2-d4) as the internal standard. Quantitative analysis was carried out by selected ion monitoring (SIM) of the carboxylated anion [M-180]- at m/z 593 and 573 for the F4-isoprostanes and PGF2-d4, respectively. DHA oxidised by AAPH or by copper ions gave rise to a similar family of F4-isoprostanes. Formation of F4-isoprostanes increased throughout the oxidation period and was correlated with other indices of lipid peroxidation (hydroperoxides and thiobarbituric acid reactive substances). The possibility of analyzing F4-isoprostanes should provide new opportunities for studying the role of lipid peroxidation in nutritional studies and in the pathogenesis of neurodegenerative diseases.

Amidines↗
PubMed1998

A 3 year prospective audit of burns patients treated at the Western Regional Hospital of Nepal.

Burns in Nepal cause an estimated 1700 deaths per year and much suffering. We carried out a prospective 3 year audit of 237 burns patients admitted to the Western Regional Hospital in Pokhara. The aims were to assess the profile of burns injuries and what could be achieved in local conditions to guide colleagues in developing countries with limited medical facilities. The majority of burns occurred at home and were largely preventable. 61 per cent of patients were children under 15 years of age. There were more female patients and females had more severe burns. No patients with greater than 40 per cent body surface area burns of any age group survived. Public education on burns prevention is needed but poverty, ignorance and a fatalistic attitude are difficult underlying causes to change.

Adolescent↗
PubMed1998

Side-effects of epidural infusions of opioid bupivacaine mixtures.

The incidence of side-effects occurring with epidural diamorphine (0.05 mg.ml-1), fentanyl (2.0 micrograms.ml-1), methadone (0.1 mg.ml-1), morphine (0.05 mg.ml-1) and pethidine (1.0 mg.ml-1) used by infusion in combination with bupivacaine has been compared. One hundred and sixty patients were studied, 32 receiving each opioid. The incidence of nausea and vomiting was significantly greater with morphine than fentanyl (p = 0.0097) and pethidine (p = 0.0021). The incidence of pruritus was significantly greater with morphine and diamorphine than with methadone (p = 0.012) and pethidine (p = 0.027). Morphine was also associated with a significantly greater incidence of urinary retention than pethidine (p = 0.012) and methadone (p = 0.025).

Aged↗
PubMed1996

Structural and functional conservation of the Drosophila doublesex splicing enhancer repeat elements.

We have compared the RNA sequences and secondary structures of the Drosophila melanogaster and Drosophila virilis doublesex (dsx) splicing enhancers. The sequences of the two splicing enhancers are highly divergent except for the presence of nearly identical 13-nt repeat elements (six in D. melanogaster and four in D. virilis) and a stretch of nucleotides at the 5' and 3' ends of the enhancers. In vitro RNA structure probing of the two enhancers revealed that the 13-nt repeats are predominantly single-stranded. Thus, both the primary sequences and single-stranded nature of the repeats are conserved between the two species. The significance of the primary sequence conservation was demonstrated by showing that the two enhancers are functionally interchangeable in Tra-/Tra2-dependent in vitro splicing. In addition, inhibition of splicing enhancer activity by antisense oligonucleotides complementary to the repeats demonstrated the importance of the conserved single-stranded structure of the repeats. In vitro binding studies revealed that Tra2 interacts with each of the D. melanogaster repeat elements, except for repeat 2, with affinities that are indistinguishable, whereas Tra binds nonspecifically to the enhancer. Taken together, these observations indicate that the organization of sequences within the dsx splicing enhancers of D. melanogaster and D. virilis results in a structure in which each of the repeat elements is single-stranded and therefore accessible for specific recognition by the RNA-binding domain of Tra2.

Alternative Splicing↗
PubMed1984

A solid-phase radio-binding assay for the characterization of lectin recognition.

A rapid and quantitative method for characterizing lectin specificity is presented. This assay is analogous to solid-phase radioimmune assays and utilizes the property of irreversible binding of proteins to vinyl microtiter plates. The lectins phytohemagglutinin and concanavalin A bind to vinyl and retain their biological properties. Iodinated fetuin and immunoglobulin G are both bound by the immobilized lectins. Competing amounts of ligands presented at the same time as the iodinated glycoproteins are shown to reduce binding to the immobilized lectins. Conversely, glycoprotein ligands immobilized to vinyl retain their ability to be recognized and bind lectins. The solid-phase binding assay can be used to characterize the ligand-binding specificity of lectins. For example, the pattern of glycoprotein inhibition of the binding of iodinated gorgonian lectin from Leptogorgia virgulata to insolubilized thyroglobulin is virtually identical to the pattern reported previously using hemagglutination inhibition. The solid-phase radio-binding assay is rapid, reproducible, and sensitive to nanogram quantities of ligand added. Most importantly, it provides quantitative information on lectin recognition.

Animals↗
PubMed1974

An Accounting of Horseradish Peroxidase Isozymes Associated with the Cell Wall and Evidence that Peroxidase Does Not Contain Hydroxyproline.

Isopycnic equilibrium centrifugation techniques were used to determine whether any horseradish (Amoracia lapathifolia) peroxidase isozymes were associated with hydroxyproline containing moieties. Purified peroxidase, horseradish root extracts, and peroxidase isozymes released from horseradish root cell walls were tested. In no case could any peak of peroxidase activity be found to band with hydroxyproline.A fluorimetric method for measurement of peroxidase activity was used to determine quantitatively the amount of total peroxidase located on horseradish root cell walls. Twenty per cent of the total peroxidase is found in the cell wall fraction after extraction; 93% of this cell wall associated peroxidase can be removed by washing with 2 m NaCl. Some peroxidase isozymes released by salt washing are not found in the cytoplasmic extract. This indicates that not all of the ionically bound peroxidase represents cytoplasmic contamination. The 1.4% of the total peroxidase activity can thus be considered tightly bound to the cell wall. Of this portion, 75% can be solubilized by treatment with a cellulase preparation. One isozyme is released which was not present in the original cytoplasmic extract.

Journal Article↗