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J Guo

Publications and source records attributed to J Guo.

At least 37 records · Page 2Linked to original sources
PubMed2005

A novel maternal lineage revealed in sheep (Ovis aries).

It is generally believed that domestic sheep have two maternal lineages (haplotypes A and B), based on mitochondrial DNA analysis. In the present study, we provide evidence that a novel maternal lineage (haplotype C) is exhibited in Chinese native sheep. To verify this finding, 231 samples were collected from six Chinese local breeds, which cover the vast geographical region of sheep inhabitation in China. For comparison, 50 samples were collected from two Western breeds collected in China. Mitochondrial DNA was screened by PCR single-strand conformational polymorphism (SSCP), leading to the identification of novel band patterns in ND2 and ND4 genes in the Chinese breeds. Interestingly, mutations at the two loci were in strong linkage disequilibrium. Direct sequencing of the DNA fragments revealed a non-synonymous substitution in ND2. Furthermore, two synonymous mutations were identified by comparisons of the novel type (haplotype C) and the established types (haplotypes A and B). The entire mitochondrial control region for 55 samples was then sequenced to construct a phylogenetic tree and median joining network. Both the tree and network demonstrated a topology of three groups, which is in consistent with the SSCP analysis. Unlike Western breeds, Chinese breeds are composed mainly of haplotypes A and B, but with a small fraction of haplotype C. According to Fu's test and mismatch distribution, haplotype C has not been subject to a recent population expansion. Based on these results, we propose a novel origin for Chinese sheep.

Animals↗
PubMed2005

Interactions between the mannose receptor and thyroid autoantigens.

Thyroid autoantigens require internalization and processing by antigen-presenting cells to induce immune responses. Besides pinocytosis, antigen uptake can be receptor-mediated. The mannose receptor (ManR) has a cysteine rich domain (CR) and eight carbohydrate recognition domains (CRD) that bind glycosylated proteins. The TSH receptor (TSHR), thyroid peroxidase (TPO) and thyroglobulin (Tg) are glycoproteins. To investigate a role for the ManR in thyroid autoimmunity, we tested the interaction between these autoantigens and chimeric ManRs. Plasmids encoding the CR-domain linked to IgG-Fc (CR-Fc) and CDR domains 4-7 linked to IgG-Fc (CDR4-7-Fc) were expressed and purified with Protein A. Enzyme-linked immunosorbent assay (ELISA) plates were coated with human thyroid autoantigens and CR-Fc or CRD4-7-Fc binding detected with peroxidase-conjugated anti-IgG-Fc. CRD4-7-Fc binding was highest for the TSHR, followed by Tg and was minimal for TPO. CR-Fc bound to Tg but not to TSHR or TPO. The interaction between the TSHR and CRD-Fc was calcium-dependent; it was inhibited by mannose (not galactose), and required a glycosylated TSHR A-subunit. Moreover, precomplexing the TSHR A-subunit with CRD-Fc (but not CR-Fc), or adding mannose (but not galactose), decreased in vitro responses of splenocytes from TSHR-immunized mice. Our data indicate that the ManR may participate in autoimmune responses to Tg and the TSHR but not to TPO. Most important, ManR binding of heavily glycosylated TSHR A-subunits suggests a mechanism by which the minute amounts of A-subunit protein shed from the thyroid may be captured by antigen-presenting cells located in the gland or in draining lymph nodes.

Animals↗
PubMed2005

T-helper cell type-2 regulation in allergic disease.

Substantial experimental evidence now supports the notion that allergic diseases are characterised by a skewing of the immune system towards a T-helper cell type-2 (Th2) phenotype. Studies using both human and mouse model systems have provided key evidence for the role that Th2 cytokines play in driving many of the hallmarks of allergic inflammation. Furthermore, the signalling pathways by which Th2 cytokines exert their effects on airway target cells are rapidly being elucidated, and antagonists of the Th2 pathway are under active development. In this review, the current knowledge of the role of T-helper cell type-2 cells in asthma is summarised, focusing on how and where T-helper cell type-2 cells differentiate from naïve precursors. The signalling molecules and transcription factors involved in T-helper cell type-2 differentiation will be reviewed in detail, in an attempt to translate studies using genetically modified mice into meaningful insights about asthma and other allergic diseases.

Animals↗
PubMed2004

Differential protein acetylation induced by novel histone deacetylase inhibitors.

Histone deacetylase (HDAC) inhibitors induce the hyperacetylation of nucleosomal histones in carcinoma cells resulting in the expression of repressed genes that cause growth arrest, terminal differentiation, and/or apoptosis. In vitro selectivity of several novel hydroxamate HDAC inhibitors including succinimide macrocyclic hydroxamates and the non-hydroxamate alpha-ketoamide inhibitors was investigated using isolated enzyme preparations and cellular assays. In vitro selectivity for the HDAC isozymes (HDAC1/2, 3, 4/3, and 6) was not observed for these HDAC inhibitors or the reference HDAC inhibitors, MS-275 and SAHA. In T24 and HCT116 cells these compounds caused the accumulation of acetylated histones H3 and H4; however, the succinimide macrocyclic hydroxamates and the alpha-ketoamides did not cause the accumulation of acetylated alpha-tubulin. These data suggest "selectivity" can be observed at the cellular level with HDAC inhibitors and that the nature of the zinc-chelating moiety is an important determinant of activity against tubulin deacetylase.

Amides↗
PubMed2004

Transport of leuprolide across rat intestine, rabbit intestine and Caco-2 cell monolayer.

The purpose of this study was to investigate the transport mechanisms and causes of low bioavailability of leuprolide. The everted gut sac technique and Caco-2 cell monolayer were used to examine: (1) transport properties, enzyme degradation and apparent permeation coefficient (Papp); (2) the influence of trypsin inhibitor, EDTA, chitosan and alginate on drug transport; and (3) the effect of animal species on the intestinal transport. Results showed flux increased with increasing concentration of drug, showing a passive diffusion pathway. The enzyme degradation in rabbit gut was the highest. The Papp of (4.19 +/- 1.33) x 10(-5) cm/s in rat gut was the largest and the Papp of (5.20 +/- 0.20) x 10(-7) cm/s in Caco-2 cell the smallest. At a low concentration of drug, trypsin inhibitor had strong enhancement effect on the Papp by protecting enough drug for permeation. Chitosan had no effect on the activity of alpha-chymotrypsin. The increase in Papp was due to opening of the tight junctions and interaction with cells. In conclusion, both inhibition of proteolytic enzymes and opening the tight junctions to allow for paracellular transport improved the intestinal absorption. At low drug concentration, reduction of enzyme degradation is the most important factor.

Alginates↗
PubMed2004

Genetic characterization of orf viruses isolated from various ruminant species of a zoo.

In the present study, an outbreak of proliferative dermatitis in musk ox (Ovibos moschatus), Sichuan takin (Budorcas taxicolor tibetana) and domestic Shetland sheep (Ovis aries) in a zoo is described. Skin lesions consisted of severe, persistent, multifocal, proliferative dermatitis in musk ox, and mild, transient, focal, dermatitis in the Sichuan takin and Shetland sheep. Parapoxviruses were isolated from skin lesions, and characterized by restriction enzyme analysis and partial gene sequencing. The results of this investigation indicate that the outbreak of proliferative dermatitis was due to infection by a single parapoxvirus, which is genetically closely related to other orf virus (ORFV) strains but distant to bovine papular stomatitis virus (BPSV) and pseudocowpox virus (PCPV).

Amino Acid Sequence↗
PubMed2004

P-glycoprotein expression is associated with FDG uptake and cell differentiation in patients with untreated lung cancer.

In vitro studies demonstrated that the accumulation of 2-deoxy-D-glucose was reduced in multidrug resistant cell lines. In animal study, it has been suggested that 2-[18F]fluoro-2-deoxy-D-glucose (FDG) may be a marker for multidrug resistance (MDR). The aim of this clinical study was to compare MDR characteristics by immunohistochemical assay with FDG uptake and investigate whether FDG is a marker for MDR in patients with untreated lung cancer. Forty-seven patients with 49 untreated lung cancers, who had undergone both preoperative FDG PET imaging and thoracotomy, were enrolled in this study. Before surgery, FDG PET was performed 40 min after injection, and standardized uptake values (SUVs) were obtained. Patients were classified into low-SUV (< or = 5) and high-SUV (> 5) groups. After surgery, the expression of P-glycoprotein (Pgp) was investigated by immunohistochemistry, and the lung cancer FDG uptake was analysed for possible association with Pgp expression. The strong intensity of Pgp immunoreactivity was seen only in the low-SUV group. The percentage of the Pgp positive area was significantly lower in the high-SUV group (21.7 +/- 13.4%) than in the low-SUV group (44.1 +/- 29.7%) (P = 0.015). In the high-SUV group, the percentage of Pgp positive area did not exceed 50%. In lung adenocarcinoma, the intensity of Pgp immunoreactivity and the percentage of Pgp positive area increased with degree of cell differentiation, while FDG uptake decreased with degree of cell differentiation. Bronchioloalveolar carcinoma, in particular, showed overexpression of Pgp and modest uptake of FDG. In conclusion, Pgp expression was found to be inversely related to FDG uptake in untreated lung cancer. Pgp expression correlated with the degree of cell differentiation in adenocarcinomas, whilst FDG uptake was inversely related to cell differentiation. FDG may be an in vivo marker for MDR in patients with untreated lung cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Chitosan-coated liposomes: characterization and interaction with leuprolide.

The objective of the present work was to investigate the effect of chitosan concentration and lipid type on the characteristics of chitosan-coated liposomes and their interactions with leuprolide. Liposomes from lipid of high purity and low purity were prepared and coated by chitosan. Physical properties, drug entrapment efficiency, and stability upon dilution were respectively compared. Results showed that the particle size increment of liposomes from low purity lipid was larger than that from high purity lipid, indicating a thicker coating layer. The high zeta potential of particles from low purity lipid was thought to play an important role in the resistance to flocculation. As to particles from high purity lipid, polymer bridging caused flocculation at low polymer concentration while at high concentration, the adsorbed chitosan molecule led to steric stabilization. Drug entrapment efficiency decreased as chitosan was added to liposomes, showing the disturbance of bilayers. Upon dilution, the leakage of leuprolide from low purity liposomes was larger than that from high purity liposomes. In conclusion, low purity lipid possessed more negative charge and formed thicker adsorptive layer by stronger electrostatic attraction with chitosan. The interaction between chitosan and the polar head groups on the surface of phospholipid bilayers may interfere with leuprolide entrapped in liposomes and result in the leakage of leuprolide.

Chitin↗
PubMed2003

Inactivation of ICa-L is the major determinant of use-dependent facilitation in rat cardiomyocytes.

Two models have been proposed to explain facilitation of the L-type calcium current (ICa-L). A positive feedback model proposes that calcium released during a conditioning pulse (I1) facilitates the subsequent pulse (I2) via calmodulin/calmodulin kinase II (CaMKII) mechanisms. The negative feedback model proposes that the calcium release of each pulse feeds back on itself via calcium-dependent inactivation. The relative physiological roles were evaluated in rat ventricular myocytes. Paired pulses (450 ms interpulse interval) elicited facilitation (I2 of 872 +/- 145 versus I1 of 777 +/- 132 pA, P < 0.01). Inactivation time (T0.37) was prolonged for I2 versus I1 (22 +/- 2 and 16 +/- 2 ms, P > 0.01). Evidence for the negative feedback mechanism includes: (a) ryanodine (0.3 mM ) eliminated facilitation, surprisingly by increasing the amplitude of I1 more than that of I2 (1039 +/- 216 and 977 +/- 186 pA) and eliminated the difference in T0.37 between I2 and I1 (33.1 +/- 4.5 versus 32.5 +/- 4.6 ms); (b) an outward I2, which does not trigger sarcoplasmic reticulum (SR) Ca2+ release, eliminated facilitation even when it was conditioned by an inward I1; (c) facilitation decayed as the I1-I2 interval lengthened (time constant (tau) = 16.9 +/- 1.4 s); (d) thapsigargin (0.1 microM ) slowed this decay (tau = 43.8 +/- 11.7 s) whereas isoproterenol accelerated it (tau = 5.6 +/- 1.4 s, P < 0.01) and T0.37 paralleled this decay; and (e) the magnitude of ICa-L was negatively correlated with the sodium-calcium exchange current (INa/Ca) elicited by the SR-Ca2+ release. In conclusion, Ca2+-dependent inactivation of ICa-L is the major mechanism underlying facilitation.

Animals↗
PubMed2003

Construction and characterization of a recombinant ovine lentivirus carrying the optimized green fluorescent protein gene at the dUTPase locus.

AdUTPase gene ( du) deleted ovine lentivirus (OvLV(Deltadu)) mutant, derived from Visna/maedi virus (VMV) molecular clone KV1772, was constructed. Subsequently, a copy of the optimized green fluorescent protein ( egfp) coding region was fused into the viral pol open reading frame (ORF) at the deleted du locus to generate viral mutant, OvLV(Deltadu-egfp). OvLV(Deltadu) reverse transcriptase (RT) activity and titer of infectious virus in goat synovial membrane (GSM) cell cultures were not affected compared to that of KV1772 and OvLV-85/34 strain (p < 0.05). By contrast, OvLV(Deltadu-egfp) RT activity and virus titer were lower than for KV1772 and OvLV(Deltadu) (p < 0.05). OvLV-85/34 RT in sheep monocyte-derived macrophages (SMDM) was higher than that of KV1772, OvLV(Deltadu) and OvLV(Deltadu-egfp) (p < 0.05). The ability to prevent dUTP mis-incorporation into newly synthesized DNA was disrupted in OvLV(Deltadu) and OvLV(Deltadu-egfp) (p < 0.05). Immunoprecipitation demonstrated that GFP is expressed by OvLV(Deltadu-egfp) at a low level. OvLV(Deltadu-egfp) retained egfp after 10 passages in cell culture.OvLV(Deltadu-egfp) was re-isolated in GSM cells from peripheral blood mononuclear (PBMN) cells of three of four OvLV(Deltadu-egfp)-inoculated lambs, but by contrast to the in vitro experiments OvLV(Deltadu-egfp) lost the insert. Priming with OvLV(Deltadu-egfp) did not prevent infection with pathogenic OvLV, but cell-associated viremia in a mock-infected contact control lamb was higher than in OvLV(Deltadu-egfp)-primed lambs. OvLV serum antibody titers increased steadily in OvLV(Deltadu-egfp)-inoculated lambs, but in a lamb from which OvLV(Deltadu-egfp) was not reisolated the antibody titer surpassed the negative/positive cut-off value only after challenge with OvLV-85/34. Because OvLV(Deltadu-egfp) is attenuated for pathogenicity in vitro, replicates in vivo and stimulates an antibody response, subsequent experiments need to address the likelihood of using OvLV(Deltadu-egfp) as an attenuated, live-virus vaccine to protect sheep against OvLV-induced disease when challenged with pathogenic OvLV.

Animals↗
PubMed2003

Characterization of a North American orf virus isolated from a goat with persistent, proliferative dermatitis.

The characterization of an orf virus (OV) isolated from skin lesions of a goat kid with severe, persistent, proliferative dermatitis, and designated orf virus-San Angelo 2000 (OV-SA00) strain, is described. The identity of OV-SA00 was confirmed by a combination of methods, including electron microscopy, amplification of specific fragments of viral DNA by polymerase chain reaction, restriction enzyme analysis of viral DNA and gene sequencing. Restriction endonuclease analyses of viral DNA and the protein profile studied by Western blot revealed differences between OV-SA00 strain and the profiles of other OV strains that have been published. The restriction enzyme profile of OV-SA00 was also different from the orf virus vaccine (OV-V) strain used to vaccinate this kid. Comparison of the nucleotide and deduced amino acid sequences indicated that OV-SA00 is closely related to OV-V strain, the Scottish OV strains orf11 and MRI Scab, and the human OV-CE/Shoe strain and more distant to bovine papular stomatitis virus (BPSV) reference strain and the pseudocowpox virus (PCPV)-MNV/Till strain. These results indicate that OV-SA00 is a strain of OV rather than a different parapoxvirus. Further studies are necessary to determine if the severity of orf-induced lesions in this goat kid was the result of individual host susceptibility factors.

Amino Acid Sequence↗
PubMed2003

Overexpression of skin protein kinase C-alpha in anagen hair follicles during induced growth of mouse hair.

A role for protein kinase C (PKC)-alpha has been implicated in the growth of mouse hair. Topical application of PKC activators, hair plucking, allergic contact dermatitis and skin irritation can all enhance growth of mouse hair, and a significant increase in PKC-alpha level in whole mouse skin in mature anagen has been demonstrated in these processes. Overexpression of PKC-alpha in anagen hair follicles has also been reported in natural growth of mouse hair. It is known that overexpression of PKC-alpha is associated with the acceleration of cell growth. Therefore, we postulated that overexpression of PKC-alpha in mature anagen may relate to enhancement of hair growth. The distribution of PKC-alpha in hair follicles during induced growth of mouse hair has not previously been studied. In this study, hair growth in C57BL/6 mice was induced by plucking the telogen hairs on one side of the back. The undepilated contralateral side served as a control. Expression of PKC-alpha in hair follicles during the hair growth cycle induced was evaluated by immunohistochemistry using cryosections and a specific polyclonal anti-PKC-alpha immunoglobulin G (IgG) antibody. No PKC-alpha was detected in telogen hair follicles or in the hair follicles at 1 day post-depilation, when the induced hair cycle was in early anagen. At 4 days after plucking, when the induced hair cycle was in mid-anagen, intense staining for PKC-alpha was found in hair papillae. At 10 and 17 days after depilation, when the induced hair cycle was in mature anagen and early catagen, respectively, all outer root sheath (ORS) cells and outer connective sheaths of hair follicles were stained positive. Because no PKC-alpha was detected in telogen hair follicles in this study, down-regulation of PKC-alpha in early anagen could not be observed. However, consistent with our previous findings, overexpression of PKC-alpha was found in mid-anagen and mature anagen. As overexpression of PKC-alpha has been shown to be associated with acceleration of cell growth, our results support the notion that PKC-alpha may play an important role in growth of hair follicle cells in induced growth of hair. As PKC levels are known to increase in hyperglycaemia, overexpressed PKC-alpha in mature anagen hair follicles may be related to the putative function of the ORS in mobilizing glycogen stores for anagen growth.

Administration, Topical↗
PubMed2003

Insight into antibody responses induced by plasmid or adenoviral vectors encoding thyroid peroxidase, a major thyroid autoantigen.

Plasmid and adenoviral vectors have been used to generate antibodies in mice that resemble human autoantibodies to the thyrotrophin receptor. No such studies, however, have been performed for thyroid peroxidase (TPO), the major autoantigen in human thyroiditis. We constructed plasmid and adenovirus vectors for in vivo expression of TPO. BALB/c mice were immunized directly by intramuscular injection of TPO-plasmid or TPO-adenovirus, as well as by subcutaneous injection of dendritic cells (DC) infected previously with TPO-adenovirus. Intramuscular TPO-adenovirus induced the highest, and TPO-plasmid the lowest, TPO antibody titres. Mice injected with TPO-transfected DC developed intermediate levels. Antibodies generated by all three approaches had similar affinities (Kd approximately 10(-9)M) and recognized TPO expressed on the cell-surface. Their epitopes were analysed in competition assays using monoclonal human autoantibodies that define the TPO immunodominant region (IDR) recognized by patients with thyroid autoimmune disease. Surprisingly, high titre antibodies generated using adenovirus interacted with diverse TPO epitopes largely outside the IDR, whereas low titre antibodies induced by DNA-plasmid recognized restricted epitopes in the IDR. This inverse relationship between antibody titre and restriction to the IDR is likely to be due to epitope spreading following strong antigenic stimulation provided by the adenovirus vector. However, TPO antibody epitope spreading does not occur in Hashimoto's thyroiditis, despite high autoantibody levels. Consequently, these data support the concept that in human thyroid autoimmunity, factors besides titre must play a role in shaping an autoantibody epitopic profile.

Adenoviridae↗
PubMed2003

In silico analysis indicates a similar gene expression pattern between human brain and testis.

OBJECTIVES: Previous data has reported similarity between human brain and testis gene expression patterns. Brain is the most important tissue in human speciation. Hence, it means that human testis could also play a crucial role in human speciation if these two tissues exhibit similar gene expression patterns. However, previous reports were based on only limited and scattered data. Determining the large scale anatomy of gene expression patterns of various human tissues could draw a more convincing conclusion, and better our understanding of the correlation/inter-correlation among different tissues. Furthermore, it could also provide a clue for evolutionary study. METHODS: To obtain gene expression information for large-scale data analysis, expression data of 760 Unigenes in seventeen human tissues (liver, lung, testis, brain, ovary, uterus, colon, stomach, heart, eye, kidney, spleen, gall bladder, breast, thymus, prostate and pancreas) were retrieved by DDD (differential digital display) analysis, and this expression data was subjected to clustering analysis. These Unigenes represent a wide range of genes classified according to their characterization and function. RESULTS: Among the 17 tissues, the highest similarity in gene expression patterns was between human brain and testis, based on DDD and clustering analysis. Genes contributing to the similarity include ribosomal protein (RP) genes as well as genes involved in transcription, translation and cell division. CONCLUSIONS: Present results provide evidence to support the proposal that human testis and brain share the highest similarity of gene expression patterns. The implications of the similarity regarding that both brain and testis contributed to human speciation are discussed.

Brain↗
PubMed2003

Severe persistent orf in young goats.

Orf (contagious ecthyma) is a viral disease of small and wild ruminants, humans, and less frequently other species. In sheep and goats, the disease is characterized by the formation of vesiculo-proliferative lesions in the skin of lips and nostril. Here, a form of generalized orf in 16 goat kids from 2 different locations in west Texas is described. The disease was characterized by multifocal, severe, proliferative dermatitis that persisted from about 2 months of age until the goat kids were euthanized 3 months later. All affected goats were Boer or Boer crosses under 1 year of age. The mean immunoglobulin concentration in sera of affected goats was elevated compared with healthy control goats. Severe to moderate lymphadenomegaly of the nodes draining the areas of the skin affected with orf lesions was present in all 16 goat kids. Suppurative arthritis, chronic fibrinous pneumonia, and premature thymic involution were found in 3, 5, and 7 of the goat kids, respectively. The skin lesions of 3 goat kids were infested with larvae of the opportunistic black garbage fly (Ophira sp.). The orf virus was identified in skin lesions by isolation in Marbin-Darby ovine kidney cells, electron microscopy, and amplification of viral DNA by polymerase chain reaction. The orf virus was not detected in peripheral blood or lymph node mononuclear cells of any of the goats. Cross-neutralization experiments showed that an ovine orf virus antiserum raised in sheep was more effective in neutralizing a sheep orf virus isolate than a caprine orf virus isolate. The clinical and epidemiological characteristics of these orf cases may be the result of susceptibility factors within some individuals of the Boer breed of goats.

Animals↗
PubMed2002

Macrophage-derived chemokine gene transfer results in tumor regression in murine lung carcinoma model through efficient induction of antitumor immunity.

Chemokine gene transfer represents a promising approach in the treatment of malignancies. Macrophage-derived chemokine (MDC) (CCL22) belongs to the CC chemokine family and is a strong chemoattractant for dendritic cells (DC), NK cells and T cells. Using adenoviral vectors, human MDC gene was transferred in vivo to investigate its efficacy to induce an antitumor response and to determine the immunologic mechanisms involved. We observed that intratumoral injection of recombinant adenovirus encoding human MDC (AdMDC) resulted in marked tumor regression in a murine model with pre-established subcutaneous 3LL lung carcinoma and induced significant CTL activity. The antitumor response was demonstrated to be CD4+ T cell- and CD8+ T cell-dependent. Administration of AdMDC induced chemoattraction of DC to the tumor site, facilitated DC migration to draining lymph nodes or spleen, and finally activated DC to produce high levels of IL-12. Furthermore, a significant increase of IL-4 production within the tumors was observed early after the AdMDC administration and was followed by the increase of IL-12 and IL-2 production. The levels of IL-2, IL-12 and IFN-gamma in serum, lymph nodes and spleen were also found to be higher in mice treated with AdMDC as compared with that in AdLacZ- or PBS-treated mice. The antitumor response induced by AdMDC was markedly impaired in IL-4 knockout mice, suggesting an important role of IL-4 in the induction of antitumor immunity by MDC. These results suggest that MDC gene transfer might elicit significant antitumor effects through efficient induction of antitumor immunity and might be of therapeutic potentials for cancer.

Adenoviridae↗