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Biomedical subjects

Y Y Liu

Publications and source records attributed to Y Y Liu.

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

Canine bullous pemphigoid (BP): identification of the 180-kd canine BP antigen by circulating autoantibodies.

Human bullous pemphigoid (BP) is an immune-mediated blistering disease characterized by autoantibodies against BP antigens (230/180 kd), which are constitutive glycoproteins of hemidesmosomes found in basal keratinocytes. Blistering diseases similar to human BP have been reported in dogs. IgG deposits at the basement membrane zone (BMZ) are a common feature of canine BP. Although circulating anti-BMZ IgG autoantibodies have been demonstrated in some cases of canine BP, the specific skin protein targeted by these autoantibodies has not been identified. In this study, we characterized the antigenic target of the autoantibodies in the serum from a 3-year-old castrated male Pit Bull Terrier with BP. Direct immunofluorescence of the patient's skin demonstrated IgG deposits at the dermal-epidermal junction. Indirect immunofluorescence demonstrated autoantibodies in the patient's serum that stained the epidermal roof of salt-split canine skin and left the dermal floor unstained. These serum autoantibodies did not stain normal intact dog skin but labeled intact bovine tongue. Direct immunoelectron microscopy of the dog's skin revealed IgG deposits within the hemidesmosomes of the basal keratinocytes. Western immunoblotting experiments showed that canine keratinocytes express both the 230-kd and 180-kd bullous pemphigoid antigens, and the autoantibodies from the patient's serum recognized the 180-kd bullous pemphigoid antigen in proteins extracted from canine and human keratinocytes. Canine BP has many parallel features with human BP including similar immune deposition of IgG within hemidesmosomes and a hemidesmosome-associated 180-kd glycoprotein target for circulating autoantibodies.

Animals↗
PubMed1995

Effects of hyperbaric oxygen on S-180 sarcoma in mice.

The contents of oxygen free radicals (OFRs) and malondialdehyde (MDA) in S-180 sarcoma tissues were measured in four groups of mice: an untreated normoxic group, a normoxic hyperbaric group, a hyperbaric oxygen group, and an HBO group treated with superoxide dismutase (SOD). Measurements were done by electron resonance and spectrophotometry, and observations were made on the volume, weight, necrosis incidence rate of sarcoma tissues, and mortality in all groups. The OFR and MDA content in sarcoma tissues in the HBO group was significantly higher than those of the control groups (P < 0.001); necrosis incidence of sarcoma tissues and the survival rate of mice were higher; the time required for necrosis was shorter, and the volume and weight of sarcoma tissues were smaller and lighter than those of the control groups (P < 0.01). The results suggest that SOD cannot completely eliminate OFRs produced by hyperbaric exposure, although the role of HBO in producing more OFRs can be counterbalanced by SOD to a certain degree. Apparently HBO can check the growth rate of sarcoma and accelerate the necrosis of S-180 sarcoma cells.

Animals↗
PubMed1995

Ceruloplasmin or fibronectin synergism with quartz dust on stimulating collagen gene transcription in human 2BS fibroblast.

Human alpha 1(I), alpha 2(I) and alpha 1(III) cDNA probes and RNA dot hybridization were employed to quantitate collagen mRNA changes after adding silica dust into the media of human 2BS fibroblasts. At all dosages used (100, 200, 500 and 1000 micrograms), the alpha 1(I), alpha 2(I) and alpha 1(III) mRNA levels increased one day after dusting. At the same dosage of silica (100 micrograms), alpha 1(III) mRNA increased earlier than type I collagen mRNA did. The type I and type III collagen mRNA contents in the experimental groups were higher than those in control on days 3, 5, 7 and 9. The effect of ceruloplasmin (Cp) and fibronectin (Fn) on collagen mRNA synthesis was also studied, after adding silica dust, Cp or Fn into the media of human 2BS fibroblast. The results showed that Cp and Fn have stimulating effect on collagen mRNA production. When both Cp and silica dust were added into cell culture media, the collagen mRNA level was increased more than those of adding either Cp or silica dust alone. Similar situations were found for Fn. Cp (or Fn) synergism with silica dust on stimulating transcription of human collagen gene was suggested.

Cells, Cultured↗
PubMed1994

Investigating the role of conserved residue Asp134 in Escherichia coli ribonuclease HI by site-directed random mutagenesis.

The role of the conserved Asp134 residue in Escherichia coli ribonuclease HI, which is located at the center of the alpha V helix and lies close to the active site, was analyzed by means of site-directed random mutagenesis. Mutant rnhA genes encoding proteins with ribonuclease H activities were screened by their ability to suppress the ribonuclease-H-dependent, temperature-sensitive growth phenotype of E. coli strain MIC3001. Based on the DNA sequences, nine mutant proteins were predicted to have ribonuclease H activity in vivo. All of these mutant proteins were purified to homogeneity and examined for enzymic activity and protein stability. Among them, only the mutant proteins [D134H]RNase H and [D134N]RNase H were shown to have considerable ribonuclease H activities. Determination of the kinetic parameters revealed that replacement of Asp134 by amino acid residues other than asparagine and histidine dramatically decreased the enzymic activity without seriously affecting the substrate binding. Determination of the CD spectra indicated that none of the mutations seriously affected secondary and tertiary structure. The protein stability was determined from the thermal denaturation curves. All mutant proteins were more stable than the wild-type protein. Such stabilization effects would be a result of a reduction in the negative charge repulsion between Asp134 and the active-site residues, and/or an enhancement of the stability of the alpha V helix. These results strongly suggest that Asp134 does not contribute to the maintenance of the molecular architecture but the carboxyl oxygen at its delta 1 position impacts catalysis.

Amino Acid Sequence↗
PubMed1994

Rat CINC/gro: a novel mediator for locomotive and secretagogue activation of neutrophils in vivo.

The effects of rat CINC/gro, a member of the interleukin-8 family, on the endothelium-neutrophil interaction and transendothelial macromolecular leakage were studied in rat mesenteric microcirculation. Thirty minutes after superfusion with 10 nM CINC/gro, the number of neutrophils adherent to the venular endothelium and those migrated across the venules were significantly increased with a concomitant elevation of luminol-dependent chemiluminescence at the site of adhesion. Transendothelial macromolecular leakage as assessed by the relative length of venular wall stained with monastral blue B was also increased at 30 min after the start of CINC/gro superfusion. Pretreatments with a CD18-directed monoclonal antibody, WT-3 (1 mg/kg), significantly attenuated the increase in number of adherent and migrated neutrophils, the increase in luminol-dependent chemiluminescence, and the venular macromolecular leakage after the application of CINC/gro. These data suggest that CINC/gro is a novel stimulator that evokes not only locomotive but also secretagogue activation of neutrophils via a CD18-dependent mechanism in vivo.

Animals↗
PubMed1994

Acylcarnitine profile in tissues and body fluids of biotin-deficient rats with and without L-carnitine supplementation.

Since biotin-deficient (BD) rats are a good animal model for human multiple carboxylase deficiency and have low plasma free carnitine levels, short-chain acylcarnitine profiles in biotin-deficient rats with L-carnitine supplementation (BDC rats) and BD rats were investigated by fast-atom bombardment and tandem mass spectrometry and gas chromatography/mass spectrometry. By the latter method, 3-hydroxyisovalerylcarnitine was identified in BD rats, and showed the greatest accumulation among short-chain acylcarnitines in tissues of BD rats, while the tissue levels of propionic acid were more markedly elevated than those of 3-hydroxyisovaleric acid. The tissue levels of 3-hydroxyisovaleryl-carnitine were significantly lower and those of propionyl-carnitine were somewhat higher in BDC rats than in BD rats, while the tissue levels of propionic acid and 3-hydroxyisovaleric acid in BDC rats were lower than those in BD rats. These changes were more apparent in kidney than in other tissues. The amounts of urinary excretion of acylcarnitines were markedly larger, and those of 3-hydroxyisovaleric acid were somewhat smaller in BDC rats than in BD rats, while those of propionic acid were very low in BD and BDC rats as compared with those of 3-hydroxyisovaleric acid. It seems that the relationship between the concentrations of 3-hydroxyisovalerylcarnitine and those of propionylcarnitine reflects the unique metabolism of the related metabolites in tissues, especially in kidney, which may be influenced by their urinary excretion and the availability of free carnitine. These data in biotin deficiency suggest that carnitine supplementation is possibly beneficial for patients with holocarboxylase synthetase deficiency who respond incompletely to biotin therapy.

Acetylcarnitine↗
PubMed1994

Abnormal fatty acid composition of lymphocytes of biotin-deficient rats.

The relative proportions (% of total fatty acids) of odd-chain (15:0-29:0) and long-chain (22:0-30:0) saturated fatty acids in phospholipids of biotin-deficient rat lymphocytes were significantly increased as compared with biotin-supplemented rats, and the ratio of unsaturated fatty acids to saturated fatty acids in the former was significantly decreased mainly due to the reduced composition of polyunsaturated fatty acids in the omega-3, omega-6, and omega-9 pathway. The ratio of cis-vaccenic acid to palmitoleic acid in biotin-deficient rats was significantly lower than that in control rats, and was thought to be another important, but previously unreported indicator of biotin deficiency. These changes imply that the elongation and desaturation of unsaturated fatty acids are depressed in lymphocytes of biotin-deficient rats, and may contribute to the associated immunological dysfunction in biotin deficiency through abnormal prostaglandin metabolism and/or cell membrane functions.

Animals↗
PubMed1994

Snail hosts of Paragonimus in Asia and the Americas.

We have undertaken a comprehensive review of snail hosts of Paragonimus world-wide exclusive of Africa based on modern malacological data, where available, and with consideration of the phylogeny of the snail groups involved. This is the first comprehensive review since those made by Chen (1979) and Chen et al. (1983), and there have been considerable taxonomic changes over the past decade. A number of names and concepts found in the medical malacological and parasitological literature up to the present time require revision or correction. There are vast radiations of snails of the superfamilies Cerithiacea and Rissoacea involved in the transmission of Paragonimus in China. We list 54 species world-wide of which 35(65%) occur in China. Revisions and corrections pertaining to China include: (i) The family Hydrobiidae does not occur in China or S.E. Asia, and the Pomatiopsidae should be used. (ii) The genus Bythinella is entirely European (Hydrobiidae: Amnicolinae). The so-called Bythinella of China belongs to the genus Erhaia (Pomatiopsidae). (iii) The generic name Pseudobythinella described from China is preoccupied, a junior synonym of Pseudobythinella Melville 1956, a fossil from England. All Chinese Pseudobythinella are now classified as Erhaia. (iv) Akiyoshia has been used as a generic name for some snails in Hunan transmitting Paragonimus. Akiyoshia is from Japan and biological/ecological data indicate that the Chinese taxon is not Akiyoshia. (v) The genus Tricula in recent Chinese literature is comprised of four genera determined by detailed comparative anatomical data: Tricula, Neotricula, Gammatricula, and Jinhongia. Shells cannot be used to discriminate among them. (vi) Tricula cristella has been consistently misidentified in collections in China and literature. However, genuine T. cristella does transmit Paragonimus skrjabini. (vii) Tricula minutoides in the Chinese literature has been misidentified, and specimens are T. cristella. (viii) The genus Melania and the family Melaniidae are used in the Chinese literature. The so-called melaniidae snails belong to the families Thiaridae, Pleuroceridae, and Melanopsidae. Asian Semisulcospira is pleurocerid while Melanoides and Tarebia are thiarid (ix) Semisulcospira libertina is correctly identified for populations ranging throughout Japan to Taiwan. This species is most probably not distributed throughout all south China, and intense systematic research on Semisulcospira is needed. A modern classification is given for snails transmitting Paragonimus.

Americas↗
PubMed1994

[Response rate of small cell lung cancer treated with CE-CAP alternating chemotherapy].

From Sep. 1989 to Dec. 1992, 122 evaluable patients with small cell lung cancer (SCLC) treated with chemotherapy combined with radiotherapy in our hospital were analysed. There were 95 men and 27 women. The age ranged from 20 to 70 years. All were proven by pathology or cytology. They all did not receive previous treatment and had a measurable mass. Of them, 83 patients had limited disease (LD) and 39 extensive disease (ED). Using CE-CAP alternating chemotherapy, 48 LD and 27 ED were given two cycles, 35 LD and 12 ED four cycles. In this series, remission time was not evaluated because all patients received radiotherapy shortly after chemotherapy. Of 122 patients, 10 patients (8.2%) achieved CR, 89 (72.9%) PR, 18 (14.7%) S and 5 (4%) P. The total response rate was 81.1% (99/122), which is higher than that of COMVP and PE-CAV regimens. The response rates were 80.0% and 82.9% in two and four cycle groups, respectively. There was no significant difference between the two groups. The main toxicity observed was nausea, vomiting and bone marrow suppression, but were tolerated by the patients. In conclusion, CE-CAP regimen can be recommended as the treatment of choice in SCLC.

Adult↗
PubMed1994

Characteristics of immunocomplex in autopsy tissues of hemorrhagic fever with renal syndrome.

Using repeated PAP or repeated PAP and ABC immunocytochemical methods, we were able to demonstrate viral antigens, Ig and Clq in the tissues of 20 autopsy materials that had been preserved for 3-30 years. Serial paraffin sections were stained with the first antibodies against both viral antigens (G2 and Np) and human IgG, IgM, C3 and Clq. Immunocomplex, composed of viral antigen, IgG and Clq were found diffusely in the cells of each organ and extracellularly in the sera, various secretions and exudates. When stained by A25 etc, coarse granular antigen or inclusion bodies were found without demonstrable Ig and Clq. It was concluded that the immunocomplex in tissues of epidemic hemorrhagic fever in Shaanxi Province, China was both intracellular and extracellular and was perhaps soluble due to antigens in excess, with characteristics quite different from that of other immune diseases.

Animals↗
PubMed1994

[Estimation of latency period of lung cancer].

A case-control study with time-related factors was conducted to estimate the latency period of lung cancer. This study included 168 incident male cases of lung cancer histologically confirmed and 336 control patients with non-neoplastic diseases. All patients were interviewed in the hospital wards from May 1987 to May 1990. Data concerning smoking, occupation, method of house heating and cooking fuel used from twelve time windows of looking forward and diet were obtained for three periods of time. A synthetical analysis of forward measures and backward measures were applied. By means of calculating accumulated effective exposure score and excess exposure fraction, the latency period of lung cancer was estimated using multivariate model. Latency of lung cancer is 54.48 years for indoor air pollution, and 56.17 years for total smoking. From estimating latency period of lung cancer from multivariate analysis, it was found that the latency of lung cancer could be affected by the effects of other factors. Therefore, measures which prolong latency period may be of use in the prevention of lung cancer.

Air Pollution, Indoor↗
PubMed1993

Pharmacokinetics of fleroxacin as studied by positron emission tomography and [18F]fleroxacin.

A new method of tracing the disposition of fleroxacin was tested in infected and noninfected animals in an effort to develop a technique that might be applicable in humans. [18F]fleroxacin was synthesized and shown to be identical physically, chemically, and in its antimicrobial activity to the commercially produced product. Tracer amounts of [18F]fleroxacin were coinjected with a pharmacologic dose of unlabeled drug (10 mg/kg) into normal mice, rats with focal thigh infection due to Escherichia coli, and normal and infected rabbits. The rats and mice were killed at fixed time intervals after injection, and the concentration of drug was determined by radioactive counting in a well-type counter; the rabbits were studied both by this method and by positron emission tomographic (PET) imaging. These studies validated the reliability of the new approach and suggested that it could be applied safely to humans. In all three animal species studied, delivery of [18F]fleroxacin to most tissues was rapid, with the notable exception of the brain. Accumulation of drug in infected thigh muscle was similar to that in normal muscle. The concentrations of drug reached in various tissues suggest that fleroxacin will be particularly useful in the treatment of gastrointestinal, urinary tract, hepatobiliary, and skeletal infections and that it shows promise for the treatment of lung and soft tissue infection. The minimal concentrations of drug delivered to the brain should decrease the occurrence of central nervous system toxicity with this particular fluoroquinolone.

Animals↗
PubMed1993

Urinary sugar phosphates and related organic acids in fructose-1,6-diphosphatase deficiency.

Two sisters with fructose-1,6-diphosphatase deficiency are reported. They presented with ketonuria, elevated plasma transaminase activity and severe metabolic acidosis during hypoglycaemic crises, which resembled Reye syndrome. Intravenous fructose tolerance tests provoked severe hypoglycaemia and metabolic acidosis. Fructose-1,6-diphosphatase activities in both peripheral leukocytes and cultured lymphocytes were below the limit of detection. Urinary organic acid analysis during crises revealed markedly increased excretion of lactate, ketone bodies, glycerol and glycerol-3-phosphate. We newly identified other glycolytic intermediates, glyceraldehyde, 3-phosphoglycerate and fructose-1,6-diphosphate, in the urine during hypoglycaemic attacks or after fructose tolerance tests. Identification of such compounds may be useful in the early diagnosis of this disease.

Female↗
PubMed1993

The effects of biotin deficiency on organic acid metabolism: increase in propionyl coenzyme A-related organic acids in biotin-deficient rats.

Volatile organic acid levels in plasma and tissues and nonvolatile organic acid levels in urine of biotin-deficient (BD) rats were measured and compared with other factors of biotin deficiency. Biotin levels and the activities of propionyl coenzyme A (CoA) carboxylase (PCC) in the livers of these rats were decreased, respectively, to 22% +/- 3% and 3.6% +/- 0.3% of the average values of pair-fed controls. Plasma concentrations of propionate were higher (15 to 223 micrograms/mL) than those of controls (5 to 7 micrograms/mL), whereas plasma levels of 3-methylcrotonate were only minimally increased as compared with those of controls. Concentrations of these volatile acids in the tissues were similarly increased, although those in brain showed less remarkable increases as compared with levels in other tissues. In the urine of BD rats, large amounts of organic acids derived from propionyl CoA, as well as those from 3-methylcrotonyl CoA, were excreted. Plasma propionate levels were not apparently related to the severity of clinical symptoms, biotin levels, or carboxylase activities, but were related to the amounts of urinary ketone bodies, lactate, and some of the organic acids derived from branched-chain amino acids, including those from propionyl CoA.

Acyl Coenzyme A↗
PubMed1993

Synthesis and biodistribution of 18F-labeled fleroxacin.

[18F]Fleroxacin (6,8-difluoro-1,4-dihydro-1-(2-[18F]fluoroethyl)-4- oxo-7-(4-methyl-1-piperazinyl)-3-quinolinecarboxylic acid) was synthesized from its methylsulfonyl ester precursor. 6,7,8-Trifluoro-4-hydroxyquinoline-3-carboxylic acid ethyl ester (Ro 19-7423) was alkylated with 2-bromoethanol to produce 6,7,8-trifluoro-1,4-dihydro-1-(2-hydroxyethyl)-4-oxo-3-quinolinecarboxyl ic acid ethyl ester in 76% yield which was then condensed with 1-methyl-piperazine to produce 6,8-difluoro-1,4-dihydro-1-(2-hydroxyethyl)-7-(4-methyl-1-piperazinyl)4- oxo-3- quinolinecarboxylic acid ethyl ester in 67% yield. This product was reacted with methanesulfonyl chloride to produce the mesylate precursor of fleroxacin in 66% yield. Nucleophilic substitution of the mesylate with 18F- in the presence of Kryptofix 2.2.2 followed by basic hydrolysis produced [18F]fleroxacin with a radiochemical yield of 5-8% [EOS] within 90 min. The pattern of biodistribution of [18F]fleroxacin was similar to the 14C-labeled drug.

Animals↗
PubMed1993

The multiplication in plants of arabis mosaic virus satellite RNA requires the encoded protein.

Oligonucleotide-directed mutagenesis was used to create two mutations at each of three positions within the open reading frame (ORF) of a cDNA clone representing a satellite RNA from a lilac isolate of arabis mosaic nepovirus (ArMV). Three of the six mutants, in which stop codons were introduced at three different sites, did not direct synthesis of a translation product. The other three mutants, in which stop codons were not introduced, directed synthesis of a translation product (39K) although, in two of these, the mutation led to a single amino acid substitution. When Chenopodium quinoa plants were inoculated with in vitro transcripts from each of the six mutants together with the genomic RNA molecules (RNA-1 and RNA-2) of ArMV, progeny RNA was detected only with two of the three mutants in which the nucleotide changes did not introduce a stop codon to the coding region. To look for complementation, two deletion mutants were made. In these, 113 or 117 nucleotides were removed from two consecutive regions within the ORF. Two insertion mutants (in which the deleted sequences were replaced with a 130 nucleotide sequence from RNA-2 of cherry leaf roll nepovirus) were also made. Transcripts from none of these mutants retained messenger activity and none was detected either in C. quinoa plants or in virions, even in the presence of wild-type satellite RNA.

Base Sequence↗