Biomedical subjects

C H Liu

Publications and source records attributed to C H Liu.

At least 91 records · Page 5Linked to original sources

PubMed1997

PIG-A gene mutations in four Taiwanese patients with paroxysmal nocturnal haemoglobinuria following aplastic anaemia.

Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired haemolytic disorder caused by deficient biosynthesis of the glycosyl phosphatidylinositol (GPI) anchor in haemopoietic stem cells. PIG-A, an X-linked gene that participates in the first step of GPI-anchor synthesis, is responsible for PNH. Various abnormalities of the PIG-A gene have been demonstrated in all patients with PNH so far examined. In this study we characterized the somatic mutations in PIG-A gene in four Taiwanese patients with PNH. We identified five novel mutations in the PIG-A gene, three single nucleotide substitution mutations (-342, C-->G, codon 335, GGT-->AGT and codon 405, GCT-->GTT) and two frameshift mutations (codon 22, GGA-->G-A and codon 356, TGT-->TGTT) in the PIG-A gene. The -342 mutation was judged to be a polymorphism. Furthermore, three patients had previous clinicopathologic evidence which suggested aplastic anaemia (AA), before the development of PNH. One of these was found to have thrombocytopenia during follow-up. We suggest that the somatic PIG-A gene mutations highlight a subgroup of AA having a pathogenetic link with PNH.

Anemia, Aplastic↗

PubMed1997

Face recognition with multi-tone and two-tone photographic negatives.

The effects of photographic negatives on face recognition are often studied in two different ways--faces are learned and tested in photographic negatives (NN) or the contrast is reversed between learning and testing, i.e. they are learned in positives and tested in negatives (PN) or vice versa (NP). We have examined recognition performance for faces under these three conditions along with a control condition where faces were learned and tested in positives (PP). Using multi-tone face images, we found that the effect of photographic negatives was more pronounced in PN and NP than in NN. No differences were found between PN and NP or between NN and PP. When two-tone face images were used, recognition performance was worse in all conditions, except PP, when compared to the multi-tone counterparts. Our results show that contrast incongruency between learning and testing is the predominant factor affecting performance and that deficits in sensory coding or retention of negative face images are unlikely to be major factors. The advantage of multi-tone over two-tone negatives can be attributed to preserved facial information carried by the high-spatial-frequency components of the image.

Adolescent↗

PubMed1997

The zebrafish BMP4 gene: sequence analysis and expression pattern during embryonic development.

We have isolated zebrafish BMP4 gene from a zebrafish genomic DNA library. The size of the isolated BMP4 gene was approximately 14.9 kb. The isolated gene contained two exons which formed the complete coding region together with part of the 3'-noncoding region. The deduced BMP4 protein sequence contained 400 amino acids. Sequence comparison showed that it shared 73% amino acid sequence identity with that of human and mouse BMP4. An intron with a size of 8,963 bp was present between two coding exons. Danio retroposon A (DANA)-like retroposon was located in the intron. It contained four conserved boxes and was flanked by a pair of direct repeats of 9 nucleotide sequence (GTTTTAATA). During embryonic development of the zebrafish, a 3.8-kb BMP4 mRNA was detected from gastrula stage up to a month-old hatching larvae via Northern blot analysis. In addition, the use of reverse transcription polymerase chain reaction further demonstrated the presence of BMP4 mRNA in both the early developmental stages (i.e., cleavage and blastula) and in adult fish. Developmental expression of BMP4 protein was also analyzed. Trace amounts of an 18-kD protein were detected at pharyngula stage, while the production increased from hatching larvae to adult fish. In adult fish, the expression of BMP4 mRNA was observed in brain, heart, digestive tracts, testes, and jaw. The results suggest that the zebrafish BMP4 gene may play important roles during zebrafish development.

Amino Acid Sequence↗

PubMed1997

A 53-base-pair inverted repeat negatively regulates expression of the adjacent and divergently oriented cytochrome P450(BM-1) gene and its regulatory gene, bm1P1, in Bacillus megaterium.

To study the role of the cis-acting element(s) in controlling the expression of the cytochrome P450(BM-1) gene and its upstream regulatory gene, bm1P1, in Bacillus megaterium, various deletion derivatives were constructed. A 53-bp inverted repeat located midway between the P450(BM-1) gene and bm1P1 gene was found in vivo to negatively regulate the expression of both genes, the regulation of which may occur at the transcriptional level. The promoter of the P450(BM-1), gene was also identified and found to be similar to those recognized by the sigmaA RNA polymerase of Bacillus subtilis. Possible mechanisms by which the 53-bp inverted repeat regulates the gene expression are discussed.

Bacillus megaterium↗

PubMed1997

[Actions of salvianolic acid A on CCl4-poisoned liver injury and fibrosis in rats].

AIM: To study the actions of salvianolic acid A (SA-A) on liver injury and liver fibrosis. METHODS: The liver fibrotic rat was made by i.p. injection of CCl4. The model rats were divided into 3 groups treated with SA-A, colchicine (Col), and Salvia miltiorrhiza Bunge (SMB), respectively. Six wk later the rat liver pathology was examined, type I and III collagen in the liver were examined by immunohistochemistical method. Also hydroxyproline (Hyd) and malondialdehyde (MDA) in the liver, alanine aminotransferase (AlaAT), aspartate aminotransferase (AspAT), and albumin (Alb) levels in the serum were measured. RESULTS: SA-A inhibited serum AlaAT and AspAT activities, decreased MDA and Hyd contents, alleviated liver fibrogenesis, protected deposition of type I and III collagen in liver matrix. The actions of SA-A on liver fibrosis were similar to those of Col and SMB, action of SA-A decreasing MDA was better than that of Col. CONCLUSION: SA-A has marked effects against liver injury and fibrosis, associated with its anti-lipid peroxidation actions.

Alanine Transaminase↗

PubMed1997

Phylogenetic analysis of feline immunodeficiency virus isolated from cats in Taiwan.

Feline immunodeficiency virus was isolated from four cats in Taiwan. The isolates were designated TI-1, TI-2, TI-3 and TI-4. Each was isolated from PBMCs following co-cultivation of PBMCs with a feline T-lymphoblastoid cell line (MYA-1 cells). However, the Taiwanese isolates did not grow in a feline kidney cell line (CRFK cells). The nucleotide sequences of the V3-V5 region of the envelope gene of the Taiwanese isolates were determined and compared with those of previously described isolates. Phylogenetic analysis of this region indicates that Taiwanese isolates belong to subtype C.

Amino Acid Sequence↗

PubMed1997

The role of nitrogenase in a cyanide-degrading Klebsiella oxytoca strain.

It is well known that the major function of nitrogenase is to fix atmospheric nitrogen. However, cyanide can also serve as a subtrate for nitrogenase and can be reduced to CH4 and NH4+. A cyanide-degrading Klebsiella oxytoca strain was isolated from cyanide contaminated water. This isolate was also found to have a nitrogen-fixation capability. Nitrogenase activities in this organism could be induced by KCN. However, there was no significant difference of the induction effect between 1 mM KCN and 5 mM KCN. It was found that the cyanide-degrading ability of this isolate could be inhibited by multicopy hybrid pGR112 nif-containing plasmids. Comparing the wild type K. oxytoca strain with the pGR112 plasmid transformed strain, a typical diauxic growth of the wild type strain was observed in a medium containing NH4Cl and KCN. Although the nif plasmid transformed strain also exhibited diauxic growth in the same medium, a much longer second lag phase was noted. In addition, methane, the nitrogenase reduction end product of cyanide, could be detected on cyanide-containing growth cultures. Ammonium chloride, a repressor of nitrogenase gene expression, was consumed prior to KCN in both strains. Again, the degradation of KCN in the pGR112 transformed strain occurred only under loose control of the nitrogenase gene. These findings strongly suggest that nitrogenase may be the sole cyanide-degrading enzyme in this organism.

Bacterial Proteins↗

PubMed1997

Pneumocephalus and respiratory depression after accidental dural puncture during epidural analgesia--a case report.

A case of pneumocephalus and respiratory depression after dural puncture during lumbar epidural analgesia is reported. The loss of resistance to air technique was employed to identify the epidural space. Severe respiratory depression and stuporous consciousness developed one hour after a bolus of 2 mg morphine was given epidurally at the end of operation. With computerized tomographic brain scanning and continuous observation of clinical course, the neurologic symptoms were thought to be a mixed complication of pneumocephalus and possible intrathecal morphine overdose. We suggest that in order to avoid iatrogenic pneumocephalus by inadvertent dural puncture in the attempt to identify the epidural space the use of the loss of resistance to normal saline technique or the hanging-drop technique is more reliable than the loss of resistance to air technique. A small test dose prior to a full dose is given and should not be omitted to further confirm the proper placement of the epidural catheter during epidural analgesia.

Aged↗

PubMed1996

Effect of supplementary antioxidant vitamin intake on carotid arterial wall intima-media thickness in a controlled clinical trial of cholesterol lowering.

BACKGROUND: There is accumulating experimental, epidemiological, and clinical evidence of an association between anti-oxidant vitamin intake and reduced risk of coronary heart disease. Using data from the Cholesterol Lowering Atherosclerosis Study (CLAS), we explored the association of self-selected supplementary antioxidant vitamin intake on the rate of progression of early preintrusive atherosclerosis. METHODS AND RESULTS: CLAS was an arterial imaging trial in which nonsmoking 40- to 59-year-old men with previous coronary artery bypass graft surgery were randomized to colestipol/niacin plus diet or placebo plus diet. The rate of progression of early preintrusive atherosclerosis was determined in 146 subjects using high-resolution B-mode ultrasound quantification of the distal common carotid artery far wall intima-media thickness (IMT). From the nutritional supplement database, 22 subjects had an on-trial average supplementary vitamin E intake of > or = 100 IU per day (high users) and 29 subjects had an average on-trial supplementary vitamin C intake of > or = 250 mg per day (high users). Within the placebo group, less carotid IMT progression was found for high supplementary vitamin E users when compared with low vitamin E users (0.008 versus 0.023 mm/y, P = .03). No effect of vitamin E within the drug group was found. No effect of vitamin C within the drug or placebo group was found. CONCLUSIONS: Supplementary vitamin E intake appears to be effective in reducing the progression of atherosclerosis in subjects not treated with lipid-lowering drugs while the process is still confined to the arterial wall (early preintrusive atherosclerosis).

Adult↗

PubMed1996

Plasma vitamins A and E and red blood cell fatty acid profile in newborns and their mothers.

OBJECTIVE: In this work, we have measured the plasma vitamins A and E and red blood cell fatty acid profile in newborns and their mothers and have determined whether there are any relationships between maternal blood and cord blood for the nutrients measured. SETTING: The study was performed at the Chung Shan Memorial Hospital, Taichung, Taiwan. SUBJECTS: Twenty-nine pairs of mothers and their term infants. INTERVENTIONS: Maternal venous blood was collected in the first trimester and at delivery, and cord blood was collected at delivery. Plasma vitamin A and E levels were determined by high performance liquid chromatography and red blood cell fatty acid profile was estimated by gas chromatography. RESULTS: Mothers had significantly greater plasma vitamin A and E levels and vitamin E/total lipid than their term neonates did (P < 0.05). Maternal plasma vitamin E and vitamin E/total lipid were significantly greater in the first trimester than at delivery (P < 0.05). Red blood cell phospholipid oleate and linoleate were significantly greater in maternal red blood cell than in cord blood (P < 0.05), however, stearate and arachidonate were significantly greater in the cord blood than in the maternal blood (P < 0.05). Maternal vitamin E, vitamin E/total lipid, palmitate, linoleate, arachidonate and docosahexaenoate were found positively correlated to those in their neonates (P < 0.05). CONCLUSIONS: The results suggest that there is a relationship between maternal blood and cord blood for some nutrients. Therefore, the nutritional status of mothers may affect the nutritional outcome of their neonates.

Adult↗

PubMed1996

Modulation by nicotine on binding of cerebral muscarinic receptors with muscarinic agonist and antagonist.

AIM: To study the modulatory effects of nicotine on the binding of brain muscarinic receptors. METHODS: The binding of brain muscarinic receptors with the agonist [3H] oxotremorine-M or the antagonist l-[3H]QNB was determined in the presence/absence of nicotine. RESULTS: Pre-incubation of the membrane fraction derived from rat cerebral cortex with nicotine 1.0 mumol.L-1 led to a decrease in the dissociation constant (Kd) for [3H] oxotremorine-M binding to muscarinic receptors, while the maximal binding value (Bmax) was unchanged. The Kd value for binding of the muscarinic antagonist l-[3H]QNB was concentration-dependently increased by preincubation with nicotine 0.1 nmol.L-1-10.0 mumol.L-1, with Bmax unchanged. The effect of nicotine on the Kd for l-[3H]QNB binding was prevented by mecamylamine 10 nmol.L-1, but was enhanced by dithiothreitol 10 mumol.L-1, which by itself was also capable of increasing the Kd value. CONCLUSION: Nicotine increases the affinity of brain muscarinic receptors for muscarinic agonist, but decreases the affinity of brain muscarinic receptors for muscarinic antagonist.

Animals↗

PubMed1995

Consistent presence of isochromosome 7q in hepatosplenic T gamma/delta lymphoma: a new cytogenetic-clinicopathologic entity.

Peripheral T-cell lymphoma (PTL), which is characterized by hepatosplenic presentation and the gamma/delta T-cell receptor (TCR) phenotype on the malignant cells, is a rare but distinct subtype of non-Hodgkin's lymphomas. Little is known about the chromosomal changes in these lymphomas. We report the cytogenetic analysis of three patients who had neoplastic proliferation of T gamma/delta cells in the spleen, bone marrow, and liver, but not in lymph nodes or skin. Isochromosome 7q and trisomy 8 were observed in all three patients. Isochromosome 7q as the sole abnormality has been previously reported in one patient with similar clinicopathologic features. It is suggested that i(7q) is a primary, nonrandom chromosomal abnormality in hepatosplenic T gamma/delta PTL.

Adult↗

PubMed1995

Sources of triacylglycerol accumulation in livers of rats fed a cholesterol-supplemented diet.

The source of free fatty acids (FFA) and the pathways contributing to the accumulation of neutral fats in livers of rats fed a cholesterol-enriched diet were investigated in this report. Supplementation with 1% cholesterol in the diet for four weeks resulted in hepatomegaly in the rats. The contents of cholesterol and triacylglycerols (TG) per gram liver measured in rats fasted overnight increased by 48 mg (approximately tenfold) and 66 mg (approximately fourfold), respectively. The activities of glycerophosphate acyltransferase and diacylglycerol acyltransferase, the two key enzymes for TG synthesis in liver microsomes, were found to increase by 23 and 19%, respectively, in the cholesterol-fed rats. The secretion of plasma TG present predominantly in very low density lipoprotein was found to decrease by approximately 30%. The incorporation of tritium from tritiated water in liver FFA increased by twofold in rats fed the cholesterol-supplemented diet, whereas the activity of CPT I in liver mitochondria decreased by 23%. The uptake of plasma FFA in vivo in livers of fasted rats maintained on the cholesterol-supplemented diet decreased by 60%. Our data thus indicate that the excess TG accumulated in livers of rats fed the cholesterol-enriched diet resulted from increased synthesis and decreased secretion of TG. To meet the demand of fatty acids for this purpose, de novo lipogenesis increased, whereas beta-oxidation decreased. Although difference in the uptake of extrahepatic FFA may be discounted, a difference in the uptake of chylomicron remnants between the control and cholesterol-fed rats may not be ruled out.

Acyltransferases↗

PubMed1995

Prediction of early pregnancy outcomes.

OBJECTIVE: A prospective study was performed on the conception hormones of early pregnancy in order to examine their sensitivity and predictability for early pregnancy loss. METHODS: The serum levels of progesterone, estradiol and human chorionic gonadotropin (hCG) were measured and analyzed at 5-8 weeks of gestation in pregnancies occurring both with and without ovarian stimulation. RESULTS: If a level of < 10 ng/ml of progesterone was chosen as the cut-off value for the prediction of early pregnancy loss, the sensitivity and specificity were 56% and 98%, respectively. The optimal cut-off value was chosen at < 0.5 multiples of the median (MoM) and < 0.4 MoM for estradiol and hCG, respectively. This gave a sensitivity of 80% for estradiol and 85% for hCG, and a specificity of 93% for estradiol and 81% for hCG at week 8 of gestation. CONCLUSION: The combined determination of conception hormones is an efficacious method of monitoring early pregnancy and may be used for predicting outcome.

Chorionic Gonadotropin↗

PubMed1995

Pelvic abscess induced by a methicillin-resistant Staphylococcus aureus from haematogenous spread via the CVP line in a burn patient.

A 38-year-old female patients was found accidentally to have a positive culture of MRSA from a routine CVP catheter tip culture 1 week after she had complete wound closure. She was recovering from a partial skin thickness burn covering 42 per cent TBSA on the trunk and extremities. Fever and hip pain developed abruptly 1 week later when she was ready for discharge from hospital. Magnetic resonance imaging (MRI) of the pelvis disclosed an intramuscular abscess. Open drainage was performed and pus culture yielded a MRSA with the same sensitivity profile as the previous CVP tip culture. Vancomycin 500 mg every 6 h was used for 3 weeks until the drain culture disclosed a negative result, and a follow-up MRI indicated a loss of the abscess space. Follow-up at an outpatient clinic 3 months later showed that the patient remained symptom free. In this patient haematogenous dissemination was the most likely route of pelvic abscess formation. It should be remembered that MRSA infection is not always only a local problem, especially in the immunocompromised condition of burn injury.

Adult↗

PubMed1995

What hinders accurate depiction of projective shape?

Adult subjects drew the visual projection of two models. One model was a trapezoid placed in the frontoparallel plane. The other was a tilted rectangle which displayed the same projective shape on a frontoparallel plane as the trapezoid. The drawing conditions were varied in two ways: the model remained available for inspection during the drawing task or it was masked after initial inspection; the subjects drew on paper placed flat on the table or on a vertical glass pane placed in front of the model (ie on a da Vinci window). The results were that (i) the projective shape of the frontoparallel trapezoid was reproduced accurately whereas that of the tilted rectangle was systemically distorted in the direction of its actual physical dimensions; (ii) when subjects drew on paper, the presence or absence of a view of the model made no difference to the amount of distortion; (iii) drawing on a da Vinci window improved accuracy even when the model was hidden. These findings provide information about the relative roles of object-centred knowledge, perceptual abilities, and depiction skills in drawing performance.

Adult↗

PubMed1995

In-vitro and in-vivo studies of the diclofenac sodium controlled-release matrix tablets.

Controlled release matrix tablets for diclofenac sodium were developed in this study. Five matrix-tablet formulations were prepared by granulating two viscosity grades of HPMC (hydroxylpropylmethylcellulose) in varying ratios with water in the planetary mixer. The in-vitro dissolution tests indicate that all five matrix formulations prolong the release of diclofenac sodium. The main factors controlling drug release were the HPMC viscosity grade and the amount of HPMC used. The larger the amount of high viscosity grade HPMC used, the slower the resultant release rate of diclofenac sodium. There was no significant degradation of diclofenac sodium or change in drug release rate in any of the five formulations during a three-month period of stability testing. The sustained release ability of four formulations was further demonstrated in an in-vivo study in six healthy subjects. There were in-vitro/in-vivo correlations between Cmax, AUC0-14, and the time for 50 or 80% drug to be released.

Adult↗

PubMed1995

Studies on the in-vitro percutaneous penetration of indomethacin from gel systems in hairless mice.

The influence of co-solvents on the in-vitro percutaneous penetration of indomethacin from gel systems was studied using a simplex lattice experimental design. Gel formulations were prepared by gelling the vehicle mixture of water, either alcohol or isopropanol and either propylene glycol or PEG 400 with 1% w/w Carbomer 940. Hairless mouse skin was employed as the barrier in a Franz-type diffusion cell. The penetration rates at steady state for seven formulations were fitted to a polynomial equation based on this simple lattice method and a three-dimensional plot was constructed. The formulation having the maximal penetration rate was determined to be the vehicle with a solvent ratio of water: alcohol: propylene glycol equal to 15:33:52, and which possessed a solubility parameter of 15 and a drug solubility of around 10 mg mL-1. When the solubility parameter of the vehicle was > 15, the drug solubility increased. However, the penetration rate decreased with an increasing solubility parameter. For those vehicles with a solubility parameter < 15, both the drug solubility and the penetration rate decreased with a decrease in the solubility parameter. There was shown to be an approximately 20-fold increase in the relative enhancement factor when using both alcohol and isopropanol, but only a threefold increase for both propylene glycol and PEG 400, when compared with water.

1-Propanol↗