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Biomedical subjects

J Guo

Publications and source records attributed to J Guo.

At least 343 records · Page 19Linked to original sources
PubMed1996

A novel "chimeric" antibody class in cartilaginous fish: IgM may not be the primordial immunoglobulin.

Using a degenerate oligonucleotide primer specific for immunoglobulin (Ig) constant type 1 (C-1 set) domain genes, products were amplified by the reverse transcriptase-polymerase chain reaction from nurse shark spleen cDNA. The deduced protein sequence of one of these clones reveals a novel Ig class in cartilaginous fish. A complete mRNA could encode a mature protein bearing an amino-terminal variable (V) domain, followed by six C-1 set domains, and ending in a carboxy-terminal tail typical of secreted IgM, IgA, and the new antigen receptor (NAR). The two amino-terminal C domains are orthologous to IgX (or IgR), an Ig heavy (H) chain class in the skate, and the last four domains are homologous to the carboxy-terminal four domains of NAR. We designate this "chimeric" Ig class IgNARC for Ig new antigen receptor from cartilaginous fish. Like NAR, but unlike shark IgM, IgNARC is encoded by very few V and C genes which apparently are not closely linked. The number of bands that hybridize with exon-specific probes varies with genomic DNA from individual sharks, suggestive of different numbers of IgNARC genes in different animals. A protein of approximately 95 kDa, which is likely to be the IgNARC H chain, is immunoprecipitated with both light chain-specific monoclonal antibodies and with antisera generated to a peptide comprising the IgNARC carboxy-terminal tail. We conclude that the arsenal of secreted antigen receptors in cartilaginous fish is greater than previously believed. In addition, our data cast doubt on the dogma that IgM is the primordial Ig isotype.

Amino Acid Sequence↗
PubMed1996

Aspergillus fumigatus peptides differentially express Th1 and Th2 cytokines.

Relevant allergens from Aspergillus fumigatus associated with allergic bronchopulmonary aspergillosis (ABPA) have been cloned and expressed. The pathogenesis of ABPA probably depends on specific cytokines and immunoglobulins secreted by lymphocytes on stimulation with different epitopes of those allergens. In the present study, we synthesized peptides of 12-16 amino acids from the sequence of Asp fI and compared their immunological responses in four mice strains (BALB/c, C57BL/6, AKR, and CBA). Of the five peptides studied for their cytokine profile, one showed a clear Th1, whereas another showed a Th2 response. The remaining three peptides varied in their immunoreactivity. The results suggest that a number of epitopes of diverse activities are present in individual molecules and may be involved in the pathogenesis of ABPA through differential cytokine secretions.

Allergens↗
PubMed1996

Heparin attenuates bleomycin but not silica-induced pulmonary fibrosis in mice: possible relationship with involvement of myofibroblasts in bleomycin, and fibroblasts in silica-induced fibrosis.

Pulmonary fibrosis was elicited in mice or rats by the intratracheal instillation of bleomycin or silica. Daily injections of heparin significantly reduced the collagen deposition in bleomycin, but not in silica, injected mice, as evaluated by the lung hydroxyproline content on day 15 after instillation. Heparin also reduced the bleomycin-induced morbidity and mortality. Study of the broncho-alveolar lavage fluid (BAL) detected no significant change in the number of leucocytes or the amount of protein in heparin treated mice. Histologies of bleomycin instilled mice suggested that heparin did reduce the alveolar remodelling but not the alveolitis, evidenced by leucocytic infiltration. As detected by electron microscopy (EM), bleomycin increased the number of leucocytes and platelets within the alveolar capillaries but this was not significant ly reduced by heparin. The phenotype of the interstitial cell involved in these two types of pulmonary fibrosis was investigated by immunohistochemistry and EM. While in bleomycin injected animals the interstitial cells had the phenotype of an actin (alpha-actin in the rat) and lipid containing interstitial cell, with a poorly developed RE, in silica injected animals in contrast, the interstitial cells were without cytoplasmic actin or lipid but with a markedly developed endoplasmic reticulum (ER). Thus bleomycin and silica induced the growth of two different types of interstitial cells, the myofibroblast and the regular fibroblast, which might be a reason why heparin selectively inhibits bleomycin but not silica-induced fibrosis.

Animals↗
PubMed1996

Vascular bundle implantation into bone for aseptic necrosis of the lunate.

Since April 1986, implantation of a vascular bundle containing the ramus carpeus dorsalis of the interosseal anterior artery and vein into the lunate has been undertaken for aseptic necrosis of the lunate bone. A series of 11 cases were performed in East-South Hospital with satisfactory results. The average follow-up period was 36 months. A series of follow-up roentgenograms reveal that necrosis of the lunate bone is being continuously repaired. Fourteen months postoperative, the following results are obtained: (1) the sclerosis of the lunate bone has completely disappeared on the roentgenograms, (2) the architecture and density of the lunate bone have returned to normal on the roentgenograms, (3) technically colorized X-ray films show that lunate bone density decreases after the operation (the decreasing range is 20 to 44 Gray scale [mean, 30.3 +/- 2.4 Gray scale]) and that the cyst formations on the lunate bone have completely disappeared postoperatively, and (4) pain in the affected wrists disappeared and patients have returned to their former work, including manual labor. The necrotized lunate bones are healed. Anatomic study shows that the presence of the ramus carpeus dorsalis of the interosseal anterior artery and vein on the wrist is 100%, and the structure as well as location of the ramus carpeus dorsalis has little anatomic variation and is long enough to be transplanted into the lunate bone.

Adult↗
PubMed1996

Geographical distribution of the human polyomavirus JC virus type A and B and isolation of a new type from Ghana.

The JC polyomavirus (JCV) is ubiquitous in humans infecting children asymptomatically, then persisting in renal tissue. Since JCV DNA can be readily isolated from urine, it should be a useful tool with which to study the evolution of DNA viruses in humans. We showed that JCV DNA from the urine of Japanese, Taiwanese, Dutch and German patients can be classified into A and B types, based upon restriction fragment length polymorphisms (RFLPs). This work was extended in the present study. We established multiple JCV DNA clones from the UK, Spain, Italy, Sweden, South Korea, People's Republic of China, Malaysia, Indonesia, Mongolia, India, Sri Lanka, Saudi Arabia, Ethiopia, Kenya, Zambia, South Africa and Ghana. Using type-specific RFLPs, most clones except the four clones from Ghana were classified as either type A or B. We constructed a molecular phylogenetic tree for the Ghanaian clones and several representative type A and B clones. According to the phylogenetic tree, the Ghanaian clones constituted a major new group, tentatively named type C. From the findings presented here and elsewhere, the following conclusions were drawn: (i) type A is prevalent only in Europe; (ii) type B is found mainly in Asia and Africa; and (iii) type C is localized to part of Africa. Our findings should help to clarify how JCV evolved in humans.

Base Sequence↗
PubMed1996

In vivo inhibition of hepatitis B viral gene expression by antisense phosphorothioate oligodeoxynucleotides in athymic nude mice.

Antisense oligodeoxynucleotides strategies have been used both to study normal gene function and to block gene expression therapeutically. We have previously shown that a number of antisense oligonucleotides against hepatitis B virus (HBV) mRNA are able to inhibit viral gene expression in vitro. Here we report the establishment of an animal model producing HBV markers in athymic nude mice and inhibition of HBV gene expression and replication by antisense DNA in vivo. 2.2.15 cells (Hep-G2 cell line transfected with HBV genomes) were injected subcutaneously (s.c.) into athymic BALB/c nude mice at a total cell number of 0.5-1 x 10(8) per mouse. Transplanted tumours developed about 2 weeks after inoculation. Hepatitis B surface and e antigens (HBsAg and HBeAg), as well as HBV DNA, could be detected in the circulation of tumour-bearing mice. Hepatitis B surface antigen and hepatitis B core antigen (HBcAg) were demonstrated in tumour cells. After 10 days of tumour growth, antisense phosphorothioate oligonucleotide, complementary to the cap site of the SP II promoter of HBV mRNA, were injected by infiltration into or around the tumour as a daily dose of 20 micrograms per gram body weight. Treatment for a total of 10 days resulted in an effective inhibition of viral replication and gene expression. These results suggest therapeutic potential for antisense oligomers in the treatment of patients who are chronically infected with HBV.

Animals↗
PubMed1996

Regulation of HSP70 by PTH: a model of gene regulation not mediated by changes in cAMP levels.

Parathyroid hormone (PTH) activates both adenylate cyclase and phospholipase C in target cells, and cloned PTH/PTH-related protein (PTHrP) receptor can mediate both responses when expressed in host cells such as LLC-PK1 renal epithelial cells. Because calcitonin (CT) is known to augment 70-kDa heat shock protein (HSP70) mRNA by an adenosine 3',5'-cyclic monophosphate (cAMP)-independent mechanism in LLC-PK1 cells, we examined regulation of HSP70 transcription by PTH in these cells. Like CT, human PTH-(1-34) [hPTH-(1-34); 10(-10) to 10(-7) M)] increased porcine HSP70 mRNA and human HSP70 promoter-chloramphenicol acetyltransferase (CAT) expression within 4 h in LLC-PK1 cells that stably express > or = 100,000 PTH/PTHrP receptors per cell. The effect of PTH on HSP70 mRNA was not mimicked by cAMP analogues, forskolin, phorbol esters, Ca2+ ionophores, or alpha-thrombin; was insensitive to pertussis toxin; and was not due to increased mRNA stability. The upregulation of HSP70 gene transcription by hPTH (and CT) was clearly observed even after deletion of the functional heat shock consensus element in the promoter region of the human HSP70/CAT reporter. Upregulation of HSP70 transcription via endogenous PTH receptors also was observed in the osteoblastic cell lines SaOS-2 and ROS 17/2.8. Regulation of HSP70 gene transcription by PTH may be a common cellular response to the hormone, which, in some cells, may not be mediated by activation of adenylate cyclase or protein kinase C.

Animals↗
PubMed1996

Neutralization of TGF-beta by anti-TGF-beta antibody attenuates kidney hypertrophy and the enhanced extracellular matrix gene expression in STZ-induced diabetic mice.

Diabetic nephropathy is characterized by renal hypertrophy, thickening of basement membranes, and accumulation of extracellular matrix in the glomerular mesangium and the interstitium. Our previous investigations have shown that high glucose concentration increases transforming growth factor (TGF)-beta1 mRNA in mesangial and proximal tubule cells and that treatment with anti-TGF-beta antibody results in prevention of the effects of high glucose on cell growth (e.g., induction of cellular hypertrophy) and the stimulation of collagen biosynthesis. We evaluated in vivo the functional role of the renal TGF-beta system in diabetic kidney disease by treatment of streptozotocin-induced diabetic mice with either a neutralizing monoclonal antibody against TGF-beta1, -beta2, and -beta3 (alphaT) or nonimmune murine IgG for 9 days. Diabetic mice given IgG demonstrated total kidney and glomerular hypertrophy, significantly elevated urinary TGF-beta1 protein, and increased mRNAs encoding TGF-beta1, type II TGF-beta receptor, alpha1(IV) collagen, and fibronectin. Treatment of diabetic mice with alphaT prevented glomerular hypertrophy, reduced the increment in kidney weight by approximately 50%, and significantly attenuated the increase in mRNA levels without having any effect on blood glucose. The antibody was without significant effect on mRNA levels in nondiabetic mice. This is the first demonstration that the early characteristic features of diabetic renal involvement, which include hypertrophy and increased matrix mRNAs, are largely mediated by increased endogenous TGF-beta activity in the kidney and that they can be significantly attenuated by treatment with neutralizing anti-TGF-beta antibodies.

Animals↗
PubMed1996

[Investigation on VNTR in intron 40 of vWF gene in Chinese Han population].

The VNTR in the intron 40 of vWF gene was investigated with a method of combination of Amp-FLP and RFLP. Two amplified fragments from a heterozygous person were separated by a non-hydratable polyacrylamide electrolyte gradient electrophoresis. After elution from gel, the preliminary products were amplified again, the amplified fragments were digested with AluI, then the genotype could be directly determined through electrophoresis. For the first time SSCP was used to detect the subtypes of microsatellite DNA. 136 alleles were found from 156 unrelated Hans in Changsha area. There were 153 genotypes in this sample and all of them were heterozygous. The calculated heterozygosity was 0.9884. The distribution of genotypes was in according with the Hardy-Weinberg equilibrium. The polymorphic information content (PIC) was 0.9883. The polymorphism of this VNTR was the highest one in the Amp-FLPs that had been found before. Our data did not show any recombination even in 2 generations of 66 families and 3 generations of 5 families. Aco-dominant segregation was demonstrated.

Base Sequence↗
PubMed1996

[Preventive effect of gene therapy with pro-uk gene on the formation of intimal hyperplasia of vascular anastomotic site].

OBJECTIVES: To develop a new way to prevent vascular anastomotic sites from intimal hyperplasia, we applied medical suture which had been soaked in pN2-pro-uk plasmid solution to perform rat carotid artery end-to-end anastomosis and study the effect of gene therapy with pro-uk gene on the formation of intimal hyperplasia of vascular anastomotic sites. METHODS: 11/0 nylon medical suture which had been soaked in pN2-pro-uk plasmid solution was applied to perform rat carotid artery end to end anastomoses. The rats were randomly divided into control and treatment groups. In the control group, medical suture was soaked in the pN2 plasmid solution for 72 hours before use. In the treatment group, medical suture was soaked in the pN2-pro-uk plasmid solution. By means of Northern blot analysis, pro-urokinase activity assay, the number detection of cr-51 labelled platelets accumulating at anastomotic sites, 3H-TDR incorporation detection of anastomotic sites, pathological changes study, the following results were obtained. RESULTS: When isolated RNA was hybridized with the radiolabeled pro-uk probe, band appeared in Northern blot analysis in the treatment group, but band could not be found in the control group. The pro-uk activity could be detected on the 2nd, 7th, 14th, 90th day in the treatment group, but could not be detected in the control group. The number of platelets accumulating at the anastomotic sites, the average intimal area and 3H-TDR incorporation of anastomotic sites were significantly fewer in the treatment group than in the control group (P < 0.01). CONCLUSIONS: When medical suture which has been soaked in pN2-pro-uk plasmid solution is used to perform vascular anastomoses, the foreign gene can produce pro-uk at anastomotic sites and effectively prevent the formation of intimal hyperplasia. The mechanism is probably related to the decrease of platelets accumulating at anastomotic sites. This study provides a new way to prevent vascular anastomotic sites from intimal hyperplasia.

Anastomosis, Surgical↗
PubMed1996

Inhibition of hepatitis B virus in vitro by antisense oligonucleotides.

A series of antisense phosphorothioate oligodeoxynucleotides against hepatitis B virus (HBV) were synthesized and evaluated for their antiviral effect in Hep-G2 cells transfected with HBV genome. The inhibitory effect of the tested antisense oligonucleotides was sequence-specific, dose-and time-dependent, and synergistic for certain combinations. In virus-inhibitory concentrations the oligonucleotides were harmless to 2.2.15 cells. The most effective antisense oligonucleotides were found directed against the HBV mRNA transcribed from the cap site of SP II promoter, the portion of polyadenylation signal and the initiation region of gene S, with an inhibition of the HBsAg and HBeAg production by 85-95% and 50- 60%, respectively. To our surprise, antisense oligonucleotides directed against three key sites of HBV X gene blocked the expression of HBsAg, HBeAg and HBxAg. This fact might be related to the trans-activation of HBV X protein. Using radioisotope labelling, we demonstrated that Lipofectin promoted the cellular uptake and antiviral effect of antisense oligomers in 2.2.15 cells. These results suggest a therapeutic potential of antisense oligonucleotides in the treatment of patients chronically infected with HBV.

Antiviral Agents↗