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Biomedical subjects

P Yu

Publications and source records attributed to P Yu.

At least 91 records · Page 5Linked to original sources
PubMed1999

[Detection of insertion/deletion polymorphism of angiotensin converting enzyme gene in preeclampsia].

OBJECTIVE: To establish a method for sensitive, specific and rapid detection of the angiotensin converting enzyme(ACE) genotypes and to study the relationship between the ACE gene polymorphism and preeclampsia. METHODS: Sixty patients with preeclampsia and 76 normal pregnant women as controls were investigated. A pair of primers, for the intron 16 of ACE gene was designed. A sensitive and specific method for detecting the ACE polymorphism of the insertion/deletion was established. Determined by polymerase chain reaction (PCR),a 490bp(I) and 190bp(D) PCR product was identified,corresponding to the PCR amplification of the allele with or without the insertion. RESULTS: The subjects were classified, according to the presence or absence of a 287bp insertion in intron 16 of the ACE gene, as II, DD, or heterozygotes for deletion/insertion (DI). The frequency of allele gene (0.75) and the percentage of the ACE DD genotype (65%) in the preeclampsia group were significantly higher as compared with the frequency 10.308 and the percentage (10.5%) in the control group respectively. CONCLUSION: Genotype II of ACE is a marker for reduced risk for preeclampsia and DD is a risk gene.

Female↗
PubMed1999

Elf3 encodes a novel 200-kD beta-spectrin: role in liver development.

beta-spectrins are crucial for the maintenance of cell shape, the establishment of cell polarity, and the formation of distinct membrane domains. Our strategy for identifying genes important for hepatocyte polarity has been to utilize subtractive hybridization of early embryonic mouse cDNA liver libraries. As a result, we have cloned three isoforms of a novel beta-spectrin elf (embryonic liver beta-fodrin), and here we report the analysis of elf3, the longest isoform (8172 nt). ELF3 comprises 2154 residues with an overall similarity of 89.0% and 95.3% to mouse beta-spectrin (betaSpIIsigma1) at the nucleotide and amino acid level, respectively. ELF3 is characterized by an actin-binding domain, a long repeat domain, and a short regulatory domain remarkable for the absence of a PH domain. Linkage analysis reveals that elf3 maps to mouse chromosome 11 between D11Bir6 and D11Xrf477, a different chromosomal locus from that of the other four spectrin genes. Northern blot analysis utilizing an elf3 3'-UTR probe demonstrates an abundant 9.0-kb transcript in brain, liver, and heart tissues. Western blot with a polyclonal antibody against ELF identifies a 200 kD protein in mouse liver, brain, kidney, and heart tissues. Immunohistochemical studies demonstrate ELF labeling of the basolateral or sinusoidal membranes surface as well as a granular cytoplasmic pattern in hepatocytes. Antisense studies utilizing cultured liver explants show a vital role of elf3 in hepatocyte differentiation and intrahepatic bile duct formation. The differential expression, tissue localization, and functional studies demonstrate the importance of elf3 in modulating interactions between various components of the cytoskeleton proteins controlling liver and bile duct development.

Amino Acid Sequence↗
PubMed1999

Lower esophageal sphincter dysfunction often precludes safe gastric feeding in stroke patients.

OBJECTIVES: To determine the relationship between stroke and lower esophageal dysfunction with vomiting and to identify an optimal nutrition protocol based on our findings. PATIENTS AND METHODS: The lower and upper esophageal sphincter functions were assessed in 35 patients who had an acute stroke to determine whether gastric or jejunal enteral feeding was the optimal route. Stroke was due to unilateral ischemia in 20 patients, unilateral intracerebral hemorrhage in 8 patients, and global ischemia in 7 patients. Our study consisted of 18 men and 17 women with an average age of 64 years. RESULTS: Using standard esophageal manometric definitions, the lower esophageal sphincter function was below normal in 24 patients: 3 had global anoxia, 5 had unilateral hemorrhage, and 16 had unilateral ischemia. The upper esophageal sphincter function was low in 30 patients: 6 had global anoxia, 7 had unilateral hemorrhage, and 17 had unilateral ischemia. Based on lower esophageal sphincter pressure, 7 patients underwent tube gastrostomy and 13 patients underwent tube jejunostomy placement. All tolerated enteral alimentation well. Prior to lower esophageal sphincter assessment, 4 patients had percutaneous endoscopy gastrostomy feedings that led to aspiration pneumonitis and consultation for tracheostomy; 2 terminally ill patients were referred to the ethics service, and 2 were converted to feeding via jejunostomy tube at the time of tracheostomy and did well. CONCLUSIONS: Vomiting with aspiration due to lower esophageal sphincter dysfunction is common after acute strokes. Esophageal manometry serves as a guide to find the optimal feeding route.

Adult↗
PubMed1999

CD40-deficient mice infected with the defective murine leukemia virus LP-BM5def do not develop murine AIDS but produce IgE and IgG1 in vivo.

CD40-deficient mice, when inoculated with the LP-BM5def murine retorvirus, become infected and show virus expression similar to wild-type mice. However, unlike the wild-type mice, CD40-deficient mice do not develop symptoms of immunodeficiency, lymphoproliferative disease and the typical histological changes in the lymphoid tissue. These results show that the CD40-CD40 ligand (CD40L) interaction in vivo is essential for anergy induction and the subsequent development of immunodeficiency and pathologic expansion of lymphocytes. Infected CD40-deficient mice and their littermates express a similar pattern of cytokine mRNA, which is not biased towards a Th2 phenotype. Nevertheless, hypergammaglobulinemia is induced in infected wild-type and CD40-deficient mice. Surprisingly, murine AIDS infection even induces IgE production in CD40-deficient mice in vivo. Our data demonstrate that antibody class switch to IgE and IgG1 can be induced by a retroviral infection in vivo even in the absence of CD40-CD40L interaction and an apparent switch to a Th2 cytokine production.

Animals↗
PubMed1999

Genomic structure, chromosomal mapping, and muscle-specific expression of a PH domain-associated intronless gene, cded/lior.

The aim of our study was to isolate novel gene(s) involved in cell differentiation and embryonic liver development. Mouse cded/lior was identified from subtraction hybridization of embryonic liver cDNA libraries as well as an adult mouse liver genomic DNA library. The full open reading frame of cded/lior encodes a 131-amino acid protein with 71.88% overall similarity to the PH domain of rat PLC-gamma1. A gapped search with the C-terminal region of CDED/LIOR revealed a 36-41% similarity to several proteins related to signal transduction and cell replication, such as ORC1 and KSR. Northern blot analysis of adult mouse tissues shows a strong 2.6-kb transcript restricted to heart and skeletal muscle. RT-PCR utilizing cded/lior-specific primers demonstrates cded/lior mRNAs in heart, brain, and liver tissue throughout mid-embryonic mouse gestation. cded/lior maps to the distal end of mouse Chromosome (Chr) 2. Analysis of the genomic structure for cded/lior demonstrated a single exon gene that is not an alternatively spliced isoform of PLC-gamma1. Analysis of the cded/lior promoter region revealed a high GC-content, high ratio of CpG/GpC, multiple GC-boxes, the lack of a TATA box, CTF/NFI element, and two MyoD-MCK binding sites. These characteristics are also found in several genes important in the regulation of cell growth or DNA synthesis, such as transforming growth factor-beta1, c-Ha-ras, nerve growth factor, epidermal growth factor receptor, and DNA polymerase beta. These results suggest that cded/lior is a mesoderm/muscle-specific transcript that may be involved in the mesodermal inductive and regulatory interactions required for liver formation and embryonic development.

Amino Acid Sequence↗
PubMed1999

Genomic organization and expression analysis of mouse kynurenine aminotransferase II, a possible factor in the pathophysiology of Huntington's disease.

Decreased levels of the endogenous neuroprotectant kynurenic acid (KYNA) have been observed in the brain of Huntington's Disease (HD) patients and may be related to neuronal loss in this disorder. This reduction may be caused by a dysfunction of kynurenine aminotransferase II (KAT II), the major enzyme responsible for the synthesis of KYNA in the brain. Towards understanding the role of KAT II in HD, we isolated and characterized the cDNA sequence and determined the genomic organization of mouse KAT II (mKat-2). The full length mKat-2 cDNA is 1812 bp, encoding 425 amino acids, and shares 89.9% amino acid similarity with the rat Kat-2 sequence. The gene for mKat-2 is composed of 13 exons divided by 12 intronic sequences. Northern blot analysis demonstrated that mKat-2 mRNA is mainly expressed in kidney and liver. RT-PCR showed mKat-2 expression in the brain starting from at least d11 of embryonic development. An alternative isoform mKat-2beta, derived from the usage of novel exons, shows a different expression pattern from mKat-2. Western blot analysis of various mouse tissues shows a 40-kDa protein in brain, heart, kidney, and liver. In the kidney and liver an additional 45-kDa isoform was detected. Use of the BSS chromosomal mapping panel from The Jackson Laboratory indicates that the mKat-2 gene co-segregates with polymorphic markers D8Mit129 and D8Mit128 on mouse Chr 8. Knowledge of the genomic organization, the isoform tissue-specific expression patterns, the chromosomal localization of mKat-2, and the reagents generated here, will provide the tools for further studies and allow generation and characterization of mice that are nullizygous for mKat-2.

Amino Acid Sequence↗
PubMed1999

Ethylenediamine-palladium(II) complexes with pyridine and its derivatives: synthesis, molecular structure and initial antitumor studies.

The synthesis of four mononuclear palladium complexes of general formula [Pd(en)Cl(L)]NO3 (en = ethylenediamine; L = pyridine (I), 4-methylpyridine (II), 4-hydroxypyridine (III) or 4-aminopyridine (IV) has been achieved. The structure of these compounds was studied by elemental analysis, IR, far-IR and 1H NMR; complex I was analyzed by X-ray diffraction. The crystal of [Pd(en)(pyridine)Cl]NO3 is monoclinic, space group P21/c (a = 7.990(2), b = 16.058(3), c = 9.846(2) A, beta = 103.81(3) degrees, Z = 4, R = 0.067, Rw = 0.066). The Pd(II) atom exhibits an approximately square planar coordination with bond lengths in the range 2.017-2.042 A for Pd-N and 2.320 A for Pd-Cl. In order to determine the donor strength of the aromatic pyridine ligands, the stability constants of binary complex ML2+ (M = [Pd(en) (H2O)2]2+; L = pyridine, 4-Me-pyridine, 4-OH-pyridine and 4-NH2-pyridine) were determined by potentiometric pH titration in aqueous solution (T = 25 degrees C, I = 0.1 mol l-1 NaNO3). The results show that the stability constants of the binary complexes systematically increase with increasing pKa of the pyridines. The above four palladium complexes, [Pt(en)(pyridine)Cl]NO3 and cis-diamminedichloroplatinum (II) (cis-DDP) were assayed for cytotoxicity in vitro against the human leukemia cell line HL-60, and compounds I, II, III and cis-DDP show significant cytotoxic activity against HL-60.

Antineoplastic Agents↗
PubMed1999

Inhibition of alpha-smooth muscle actin expression in an in vitro wound healing model by certain antibiotics.

OBJECTIVE: This study assesses the effects of antimicrobials on wound healing in an in vitro model of chicken flexor tendons in a collagen gel matrix. Two equidistant tendons were bathed in a culture medium for 28 days as fibroblasts (fb) grew from the tendon ends into the collagen gel and migrated toward each other until gap closure. Five groups of 10 paired tendons each included the control and the study groups, which received oxacillin (Ox), clindamycin (Cl), chloramphenicol (Chl), or tetracycline (Tet) in the culture medium to assess their effects on gap closure rate, fb migration, and myofibroblast alpha-smooth muscle (alpha-SM) actin expression. RESULTS: Gap closure, by day 27, was 98.5% in the controls compared with 97%, 92%, 89.5%, 21.75% in the Tet, Cl, Ox, and Chl groups. Chl retarded gap closure (p < 0.05). Fb migration was similar for all groups. In the control and Ox groups, myofibroblast expressed actin at day 5. By day 7, fb cells were clearly visible in the control, Ox, and Cl groups, whereas, only light actin was present in the Chl and Tet groups. Actin band densities for the Cl, Ox, Tet, and Chl groups were 78.4%, 62.5%, 61.7% and 26.1%, respectively, of the control group. CONCLUSION: These studies suggest that one reason certain antimicrobials impair wound healing, is due to myofibroblast inhibition of alpha-SM actin.

Actins↗
PubMed1999

[Pathogenetic effect of platelet activating factor on enterogenic endotoxemia after burn].

OBJECTIVE: To investigate the effects of platelet activating factor (PAF) on the occurrence of enterogenic endotoxemia after burn. METHODS: The relationship between changes of PAF and enterogenic endotoxima was observed on a model of rats with 30% TBSA III degree burn. RESULTS: The intestinal permeability and plasma endotoxin were significantly elevated and were positively correlated with the increase of PAF in the intestinal tissue and blood. PAF antagonist treatment significantly decreased the intestinal permeability and the levels of plasma endotoxin. After intravenous injection of enogenous PAF to healthy rats, the intestinal permeability and plasma endotoxin were also markedly increased, which was significantly depended on the dose of PAF. CONCLUSION: PAF is one of the important factors for the occurrence of postburn enterogenic endotoximia.

Animals↗
PubMed1999

[Effect of baicalin and tetramethylpyrazine on intracranial hypertension of infectious brain edema in rabbits].

OBJECTIVE: To evaluate the effects of mannitol (MN), baicalin (BC) and tetramethylpyrazine (TMPZ) on intracranial hypertension (ICH) of infectious brain edema induced by Pertussis bacilli (PB) in rabbits. METHODS: Forty-five rabbits were divided randomly into five groups: the normal saline group (A); the pertussis bacilli group (B); the MN treated group (C); the TMPZ treated group (D) and the BC treated group (E). PB was injected into the left internal carotid artery of rabbits to establish the infectious brain edema model, their intracranial pressure (ICP) was monitored continuously by fiberoptic ICP monitor. Treatments were given intravenously 1 hour after injecting PB, and changes of ICP, brain water content (WC), Evans blue (EB), Na+, K+ and morphology were observed within 4 hours after PB or NS injection. RESULTS: MN, TMPZ and BC all could reduce the brain edema and ICH in rabbits induced by PB, the effect of MN was the most rapid and obvious one, but it lasted for rather shorter time, while the effect of TMPZ and BC was initiated later but lasted for a longer time. The ICP of Group C in 2nd to 4th hour was higher than that of Group D and Group E, but lower than that of Group B. The ICP of Group E in 3rd to 4th hour was lower than that of group D. At the same time of lowering ICP, brain WC, EB, Na+ contents and pathologic morphologic change were also alleviated. CONCLUSION: Both BC and TMPZ could reduce ICP in infectious brain edema, the effect of BC was better than that of TMPZ.

Animals↗
PubMed1999

[Effects and applications of ascorbic acid on the proliferation of Chlamydia trachomatis].

Two hundred and eighty-eight samples of patients with nongonococcal urethritis (NGU) and prostatitis were detected by cell culture and immunofluorescence assay for Chlamydia trachomatis (CT) and the effects of ascorbic acid(vitC) on the formation rate of inclusion of CT in positive samples were also studied. The results showed that the formation rate of inclusion of CT was 29.5% when the concentration of vitC was 5 micrograms.ml-1. The difference between test group and control group which contained cycloheximide in the media was insignificant (P > 0.05). The results suggested that vitC was a kind of nutrient needed for CT. The proliferation of CT in the cell can be promoted by vitC. We can replace cycloheximide by vitC in McCoy cell culture to detect clinic samples with CT.

Adult↗
PubMed1999

[Study on etiologic agents of vaginitis].

In order to provide scientific basis for preventing and curing vaginitis, etiologic agents were examined in 354 patients with vaginitis and 115 healthy women using rapid and reliable laboratory methods. The inducements of vaginitis were analysed. The results showed that candida was only detected for the normal control group. Bacteria, candida and trichomonas were the commonest causes of vaginitis. With the increasing ages of patients with vaginitis, the incidence rates of all kinds of vaginitis were lowered. Vaginitis is associated with pregnancy, using antibiotics and contraceptive, or sexual activity.

Adult↗
PubMed1999

[Study on etiology of nongonococcal urethritis].

One thousand one hundred and fifty-seven samples from urogenital tract were detected by isolating culture and immunofluorescence. The positive rates of Chlamydia trachomatis (CT), Ureaplasma Urealyticum (UU), Mycoplasma hominis (Mh), Candida (Cd), Staphylococcus aureus were 27.8%, 33.5%, 25.6%, 11.5%, 23% respectively. The rate of mixed infection caused by at least two pathogens was 19.8%. About 90% of the infected patients were from 20 to 40 years old. The related factors of pathogen detection were also studied.

Adolescent↗
PubMed1999

[Effect of pertussis bacilli on the release of excitatory amino acids in brain slice of rats].

OBJECTIVE: To investigate the effect of pertussis bacilli on the release of excitatory amino acids (EAAs) in rat-brain slice and to know whether MK-801(dizocipine) protects brain tissue from excitotoxicity. METHODS: SD rats were randomly divided into 3 groups: 1. Normal slice cultured group(NC); 2. 10% pertussis bacilli(PB) slice cultured group(PBC); 3. 10% PB slice cultured group after pretreatment with MK-801. The release of EAAs from brain slices was measured by high performance liquid chromatography. RESULTS: The concentrations of glutamate(Glu 29.53 +/- 8.00), aspartate(Asp 23.74 +/- 5.79) and LDH(38.03 +/- 8.45) were significantly higher in PBC group than those(Glu 16.46 +/- 4.00, Asp 15.27 +/- 5.31, LDH 23.10 +/- 5.11) in MPBC group and (Glu 16.09 +/- 3.74, Asp 11.47 +/- 2.51, LDH 25.82 +/- 4.50) NC group. CONCLUSION: Pertussis bacilli may elicit a large increase of extracellular EAAs and LDH in vitro, while MK-801 protects brain tissue from excitotoxicity.

Animals↗
PubMed1998

Comparison of the mode of action of a dinuclear platinum complex containing a pyridine derivative with its monomeric analog.

The DNA binding and interstrand cross-linking properties of the dinuclear platinum complex [¿cis-Pt(NH3)2Cl¿2bpsu](NO3)2 (bpsu is 4,4'-dipyridyl sulfide) (II) and the mononuclear complex [cis-Pt(NH3)2Cl(4-methylpyridine)]NO3 (I) were compared with those of [¿cis-Pt(NH3)2Cl¿2H2N(CH2)4NH2](NO3)2 (III) in order to understand the mode of action of complexes I and II. Both compound I and compound II caused significantly different changes of conformation in poly(dG-dC) x poly(dG-dC) than compound III did. Studies of DNA binding, interstrand cross-linking and fluorescence assay suggest that compound I monofunctionally binds to DNA and compound II bifunctionally binds to DNA, that the dinuclear platinum complex II more efficiently interacts with DNA compared to its monomeric analog, and that platinum I and II complexes both interact with DNA in a non-intercalative mode. All the results indicate that the mode of action of the dinuclear complex II is different from that of the mononuclear complex I.

Animals↗
PubMed1998

Identification of quinine metabolites in urine after oral dosing in humans.

A gas chromatographic-mass spectrometric method was used to separate quinine and its metabolites present in urine after oral dosing of 300 mg quinine in humans. The technique allowed the separation of quinine and ten metabolites. Four of these metabolites were definitely identified as 3-hydroxyquinine, 2'-quinone, O-desmethylquinine and 10,11-dihydroxydihydroquinine, by comparing their methane chemical ionization mass spectra with those of authentic standards prepared by organic synthesis. Six other metabolites are described for the first time in human urine. From their electron impact and chemical ionization mass spectra, we propose these compounds to be 3-hydroxy-2'-quinone, O-desmethyl-2'-quinone, O-desmethyl-3-hydroxyquinine, O-desmethyl-3-hydroxy-2'-quinone, 10,11-dihydroxydihydro-2'-quinone and 10,11-dihydroxydihydro-O-desmethylquinine. These secondary metabolites probably arose from further biotransformation of the four primary metabolites.

Administration, Oral↗