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Biomedical subjects

J Guo

Publications and source records attributed to J Guo.

At least 325 records · Page 18Linked to original sources
PubMed1997

[Discovery of a novel reassortant H1N2 influenza virus].

Three strains of influenza A virus were isolated from patients suffering from influenza like disease in Railway Hygiene and Anti-epidemic Station of Taiyuan in January 1996. The identification results by serological method indicated that the isolates were different from H1N2 subtype of influenza A virus isolated from men in 1989 and 1992 and that their HA antigenicity was similar to that of A/RP/8/34 (H1N1) virus, but distinguishable from that of influenza A (H1N1) virus circulating in mans recently. The comparison of migration patterns of the RNA among the isolates, the A/PR//34 (H1N1) and the A/Wuhan/359/95 (H3N2) viruses revealed that the migration patterns of RNA 1-4 segments of the isolates were similar to those of A/PR/8/34 (H1N1) virus, but those of RNA 5-6 segments were indistinguishable from those of A/Wuhan/359/95 (H3N2) strain. However, the migration patterns of RNA 7-8 segments of the isolates were not only different from those of A/PR/8/34 (H1N1) virus, but also distingrasgable from those of A/Wuhan/359/95 (H3N2) strain. Therefore, it could be considered that the isolates were a novel reassortant H1N2 influenza A virus.

Adolescent↗
PubMed1997

[Study on determination of composition of complex by multiwavelength R factor method].

The pure spectrum of the complex is obtained by R factor method to eliminate the absorbance of equilibrium concentration of residual reagent. The reagent concentration is determined by multiple linear regression method. As initial concentrations of metal and reagent are changed, and the stable constant is not changed, complex composition and its constant are acquired by means of trial method, in which the input parameters, m and n, are selected. Then the K value is calculated and the minimum value of the total derivation in K is found. By this method, the composition of complex in systems such as Pb-XO, Al-CAS and Zn-PAR are all to be 1:2.

English Abstract↗
PubMed1997

Pancreaticoduodenal artery aneurysm. Case report with literature review.

Pancreaticoduodenal artery aneurysms are quite rare; only 5 cases have been reported in the Chinese literature. The variable clinical presentations and high incidence of rupture make it difficult to diagnose and treat. In this paper we report a case of inferior pancreaticoduodenal artery aneurysm with literature review. The case was found incidentally during a cholecystectomy and was later successfully treated by elective surgery.

Aneurysm↗
PubMed1997

[Simultaneous detecting of C3 phenotypes and C3 cleavage by immunofixation].

The C3 phenotypes and C3 cleavage were simultaneously detected using cellulose acetate electrophoris followed by immunofixation and desitometry. Compared to crossed-immunoelectro-phoresis, this method has some advantages in resolution between different bands and was much more rapid, less expensive and more sensitive.

Complement C3↗
PubMed1997

Theoretical calculation of circular dichroic exciton-split spectra in presence of three interacting 2-naphthoate chromophores.

Ample experimental evidence shows that the principle of pairwise additivity holds in exciton coupled CD systems consisting of three or more interacting chromophores. This principle is one of the most important from a practical viewpoint. However, the rule has so far not been proven theoretically. In order to prove the additivity principle by calculation, three ouabagenin bisnaphthoates and 1,3,19-tris-naphthoates were chosen as models. Since this represents a challenging case where the 2-naphthoate chromophore can adopt s-cis or s-trans conformations and, moreover the C-19 side chain of ouabagenin is flexible, Monte Carlo conformational search was performed prior to the CD calculation. The pi-electron SCF-CI-DV MO calculation of CD was applied to all conformers within 3 kcal/mol range from the lowest energy. Good agreement between experimental and theoretical CD spectra was obtained for the ouabagenin bisnaphthoates and trisnaphthoate.

Carboxylic Acids↗
PubMed1997

[Effect of microinjection of CRH into rat central nucleus of amygdala on blood pressure and its central mechanism].

The effect of microinjection of corticotropin releasing hormone (CRH) into the central nucleus of amygdala (CeA) on blood pressure was examined in Wistar rats anaesthetized with pentobarbital sodium. The results were as follows: (1) Microinjection of CRH 100, 500 ng into the CeA produced a dose-dependent increase in blood pressure. The response occurred 5 min after injection and lasted for at least 1 h. (2) The response could be blocked by injection of CRH receptor antagonist alpha-helical CRH9-41 into CeA. (3) Lateral ventricle injection of naloxone could also attenuate the pressor response of CRH. (4) After injection of alpha-helical CRH9-41 into nucleus of solitary tract, the pressor response of CRH was diminished. The results suggest that the pressor effect induced by microinjection of CRH into the CeA might be partly mediated through opioid system via a descending pathway from CeA to NTS.

Amygdala↗
PubMed1997

[An attempt on the normalization of the moduli spectrum of pulmonary pressure and flow waveforms in canine].

There is no reference of the standard function as the input and/or output control for the pressure and flow waveforms employed by a circulation duplicator or a computational fluidddynamics investigator. The author suggested a hypothesis that the Fourier series with limited terms should be the normalization function of ventricular and great artery pressure and flow waveforms in every cardiac cycle when sinus rhythm is normal, and that the square root of the amplitudes at each harmonic of the heart rate equals to C1-C2 square root of n, where n is the ratio of harmonic/heart rate, C1 and C2 are constants. This article is to provide some procves. The main pulmonary pressure and flow waveforms of 9 mongrel canines were divided into a single cardiac cycle, electrocardiography accordingly, then harmonic was expanded by using a Fourier series with 15 harmonic terms, and the moduli and phrase spectrum of each waveform was obtained respectively and statistically processed. The results support the hypothesis. We also found that the phrases of the pressure and flow waveforms have less variation at the basic harmonic of heart rate, but the higher the frequency of the harmonics comes out, the more variable the phrases appear.

Animals↗
PubMed1997

[The function of nitric oxide in the necrosis of avulsed skin flap in domestic pig].

To investigate the function of nitric oxide (NO) and nitric oxide synthetase (NOS) inhibitor, N-nitro-L-arginine methyl ester (L-NAME), the skin avulsion model was made in the lower extremity of pig. The methods of measurement of size of the survived flap, weighing, immunocytochemistry and hybridization in situ were employed, so that the survival surface area of flaps, tissue wet/dry weight ratio, NO content in the serum, gene expression of NO and NOS content in the flap tissue were determined, respectively. The results showed that the early gene expression of NOS was increased as well as the NO content and tissue wet/dry weight ratio (P < 0.01). After L-NAME was applied introvenously, the NO content and tissue wet/dry weight ratio were decreased (P < 0.01), and the survival surface area of flaps was enlarged (P < 0.01). It could be concluded that the NO might play a role in the development of the pathological changes as early congestion, edema and secondary necrosis in the avulsed skin flaps. The early application of L-NAME could do some good to the avulsed skin flap and protect it from further necrosis owing to the presence of NO.

Animals↗
PubMed1996

Transketolase is a major protein in the mouse cornea.

Earlier experiments in this laboratory identified a highly expressed 65-68-kDa protein in both mouse and human corneas (Cuthbertson, R. A. , Tomarev, S. I., and Piatigorsky J. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 4004-4008). Here, we demonstrate that this protein is transketolase (TKT; EC 2.2.1.1), an enzyme in the nonoxidative branch of the pentose-phosphate pathway, based on peptide and cDNA isolation and sequence analysis of mouse cornea protein and RNA samples, respectively. While expressed at low levels in a number of tissues, the 2.1-kilobase TKT mRNA was expressed at a 50-fold higher level in the adult mouse cornea. The area of most abundant expression was localized to the cornea epithelial cell layer by in situ hybridization. Western blot analysis confirmed TKT protein abundance in the cornea and indicated that TKT may comprise as much as 10% of the total soluble protein of the adult mouse cornea. Soluble cornea extracts exhibited a correspondingly high level of TKT enzymatic activity. TKT expression increased progressively through cornea maturation, as shown by Northern blot, in situ hybridization, Western blot, and enzymatic analyses. TKT mRNA and protein were expressed at low levels in the cornea prior to eye opening, while markedly increased levels were observed after eye opening. Taken together, these observations suggest that TKT may be a cornea enzyme-crystallin, and suggest that the crystallin paradigm and concept of gene sharing, once thought to be restricted to the lens, apply to other transparent ocular tissues.

Amino Acid Sequence↗
PubMed1996

Parathyroid hormone-related peptide (PTHrP) regulates fetal-placental calcium transport through a receptor distinct from the PTH/PTHrP receptor.

To determine the role of PTHrP in fetal calcium metabolism, blood calcium was measured in mice homozygous (HOM) for deletion of the PTHrP gene. On day 18.5 of gestation, ionized calcium and the maternal-fetal calcium gradient were significantly reduced in HOM PTHrP-ablated fetuses compared with that of their littermates. To assess the placental contribution to the effect of PTHrP, 45Ca and 51Cr-EDTA (as a blood diffusional marker) were administered by intracardiac injection to pregnant, heterozygous dams on day 17.5 of gestation. Five minutes after the injection, whole fetal 45Ca accumulation was significantly decreased in HOM PTHrP-ablated fetuses compared with that of their littermates. Next, two fetuses from each litter were injected in utero with fragments of PTHrP, PTH, or diluent 1 h before administering 45Ca and 51Cr to the dam. PTHrP-(1-86) and PTHrP-(67-86) significantly increased relative 45Ca accumulation in HOM PTHrP-ablated fetuses, but PTHrP-(1-34), PTH-(1-84), and the diluent had no effect. Finally, similar studies were performed on fetal mice that lacked the PTH/PTHrP receptor gene. Ionized calcium was significantly reduced in HOM PTH/PTHrP receptor-ablated fetuses. However, 5 min after maternal injection of 45Ca and 51Cr, relative accumulation of 45Ca was significantly increased in these fetuses. It was concluded that PTHrP is an important regulator of fetal blood calcium and placental calcium transport. In addition, the bioactivity of PTHrP for placental calcium transport is specified by a mid-molecular region that does not use the PTH/PTHrP receptor.

Animals↗
PubMed1996

Use of virion DNA as a cloning vector for the construction of mutant and recombinant herpesviruses.

We have developed improved procedures for the isolation of deletion mutant, point mutant, and recombinant herpesvirus saimiri. These procedures take advantage of the absence of NotI and AscI restriction enzyme sites within the viral genome and use reporter genes for the identification of recombinant viruses. Genes for secreted engineered alkaline phosphatase and green fluorescent protein were placed under simian virus 40 early promoter control and flanked by NotI and AscI restriction sites. When permissive cells were cotransfected with herpesvirus saimiri virion DNA and one of the engineered reporter genes cloned within herpesvirus saimiri sequences, recombinant viruses were readily identified and purified on the basis of expression of the reporter gene. Digestion of recombinant virion DNA with NotI or AscI was used to delete the reporter gene from the recombinant herpesvirus saimiri. Replacement of the reporter gene can be achieved by NotI or AscI digestion of virion DNA and ligation with a terminally matched fragment or, alternatively, by homologous recombination in cotransfected cells. Any gene can, in theory, be cloned directly into the virion DNA when flanked by the appropriate NotI or AscI sites. These procedures should be widely applicable in their general form to most or all herpesviruses that replicate permissively in cultured cells.

Alkaline Phosphatase↗
PubMed1996

Molecular cloning of two novel rab genes from human melanocytes.

We isolated the genes of two small GTP-binding proteins of the rab family from a human melanocyte cDNA library and from melanoma cells. One gene, rab30 codes for a novel rab protein of 203 amino acids with minimal homology to previously documented GTPases. The other, rab22b, appears to be an isoform of the human homologue of canine rab22. Both rab mRNAs displayed a nearly ubiquitous pattern of expression in the various tissues examined. Rab22b and rab30 were mapped to chromosomes 18 and 11, respectively.

Amino Acid Sequence↗
PubMed1996

Autoantibody-mediated capture and presentation of autoantigen to T cells via the Fc epsilon receptor by a recombinant human autoantibody Fab converted to IgE.

Fc epsilon receptor (CD23)-mediated capture of IgE-antigen complexes by B cells provides a powerful antigen presenting system. Our goal was to develop a system using high affinity, human, organ-specific monoclonal autoantibodies for antigen capture by B cells. For this purpose, we converted a recombinant human autoantibody to TPO from a Fab (SP1.4) to an IgE molecule. Sera from all patients with autoimmune thyroid disease contain autoantibodies with the same epitope as SP1.4. The SP1.4 H and L chain V region genes were spliced by overlap PCR to a mammalian, non-immunoglobulin signal peptide and transferred to expression vectors for human IgG1 and kappa, respectively. After inserting the IgE constant region genes into the H chain vector, the kappa and IgE H chain vectors were expressed in SP2/0 cells. SP1.4-IgE retains its high affinity (Kd) for TPO (approximately 2 x 10(-10) M), recognizes the same epitope as Fab SP1.4 and, importantly binds to a different epitope than does Fab TR1.9. Binding of preformed complexes of SP1.4-IgE and biotinylated TPO to EB virus transformed B cells (EBVL) was weakly detectable by flow cytometry and was displaced by unlabeled TPO. SP1.4-IgE/125I-TPO complex binding to EBVL was much more clearly evident, was also inhibited by the addition of unlabeled TPO, and was greatly reduced by preincubation of the EBVL with anti-CD23. Further, autologous EBVL preincubated with SP1.4-IgE/TPO complexes stimulated proliferation of TPO-specific T cells. IgE autoantibody-mediated antigen focusing to B cells is unlikely to operate in vivo but is, instead, a powerful investigative tool. In conclusion, SP1.4-IgE is the first monoclonal human autoantibody to be developed for IgE-mediated antigen presentation to T cells by EBVL. Recombinant human autoantibodies converted to IgE, possibly in combinations if their epitopes permit simultaneous binding to the same molecule, provide a unique system to generate human T cell lines and clones specific for peptides naturally processed from internalized high affinity autoantibody/autoantigen complexes.

Antigen Presentation↗