Genetic segregation of spontaneous erosive arthritis and generalized autoimmune disease in the BXD2 recombinant inbred strain of mice

The BXD2 strain of mice is one of approximately 80 BXD recombinant inbred (RI) mouse strains derived from an intercross between C57BL/6J (B6) and DBA/2J (D2) strains. We have discovered that adult BXD2 mice spontaneously develop generalized autoimmune disease, including glomerulonephritis (GN), increased serum titres of rheumatoid factor (RF) and anti-DNA antibody, and a spontaneous erosive arthritis characterized by mononuclear cell infiltration, synovial hyperplasia, and bone and cartilage erosion. The features of lupus and arthritis developed by the BXD2 mice segregate in F2 mice generated by crossing BXD2 mice with the parental B6 and D2 strains. Genetic linkage analysis of the serum levels of anti-DNA and RF by using the BXD RI strains shows that the serum titers of anti-DNA and RF were influenced by a genetic locus on mouse chromosome (Chr) 2 near the marker D2Mit412 (78 cm, 163 Mb) and on Chr 4 near D4Mit146 (53.6 cm, 109 Mb), respectively. Both loci are close to the B-cell hyperactivity, lupus or GN susceptibility loci that have been identified previously. The results of our study suggest that the BXD2 strain of mice is a novel model for complex autoimmune disease that will be useful in identifying the mechanisms critical for the immunopathogenesis and genetic segregation of lupus and erosive arthritis.

Application of recipient-derived dendritic cells to induce donor-specific T-cell hyporesponsiveness

Administration of donor-derived immature dendritic cells (DC) treated with NF-kappaB oligodeoxyribonucleotides (ODN) prevents allograft rejection. We attempted to explore the use of recipient-derived DC pulsed with donor antigens, in which the donor antigens were presented to host T cells via an indirect pathway (cross-priming). Expression of CD40, CD80, and CD86 on DC was significantly inhibited by treatment with NF-kappaB ODN, whereas MHC class I and II were minimally affected. Normal C3H DC pulsed with B10 antigens stimulated proliferative responses and donor-specific CTL activity in C3H T cells, both of which were, however, markedly inhibited when DC were treated with NF-kappaB ODN. This manipulation was associated with reduced IFN-gamma and increased IL-10 production in the supernate, suggesting a Th2 bias. More frequent apoptotic T cells were observed in cultures with NF-kappaB ODN DC. In contrast to administration of normal DC pulsed with donor antigens that accelerated rejection of B10 cardiac allografts (median survival time [MST] 7 days versus 10 days in no-DC treatment control, P < .05), a single injection of 2 x 10(6) NF-kappaB ODN DC significantly prolonged allograft survival (MST 50 days, P < .05 compared with no-DC treatment control). The anti-donor CTL activity in infiltrating T cells isolated from cardiac grafts in recipients that received NF-kappaB ODN DC was significantly suppressed. These data indicate that vaccination with immature DC, propagated from recipient BM is an attractive approach to induce T-cell hyporesponsiveness.

Acquired inhibitor of factor V: first report in China and literature review

We reported a 51-year-old man who developed a severe haematuria with a prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT). Laboratory evaluation revealed the presence of specific factor V inhibitors. No underlying diseases and associated conditions have been identified. The patient improved after immunosuppressive therapy. However, the FV level remained low, indicating incomplete inhibitor eradication. The clinical course of our patient was consistent with the observations by others that FV inhibitor can be persistent for months or years.

Liver stellate cells suppress dendritic cells through IL-10

Liver allografts can be spontaneously accepted across an MHC class I disparity, the mechanism of which is still not known. Since the liver has a large amount of immature dendritic cells, these elements may contribute to transplant acceptance. However, the reason why liver dendritic cells are immature status is unknown. In this study, bone marrow-derived dendritic cell progenitors were cocultured with liver stellate cells, which produce the immunosuppressive cytokines IL-10 and TGF-beta. The results revealed that dendritic cells cocultured with liver stellate cells express low levels of costimulatory molecules with decreased allostimulatory capacity. Addition of anti-IL-10 antibody to the culture media to neutralize IL-10 effects reversed the allostimulatory function of dendritic cells cocultured with stellate cells. In conclusion, liver dendritic cells are conditioned by stellate cells to maintain an immature status, which may contribute to the low immunity of liver. One of the mechanisms that stellate cells may influence dendritic cells is through IL-10.

VEGF165 and angiopoietin-1 decreased myocardium infarct size through phosphatidylinositol-3 kinase and Bcl-2 pathways

Angiogenic growth factors, vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang1) could decrease myocardial infarct size, which was assumed to be related with newly formed capillaries. We doubted that these capillaries could do this solely and the potential protective mechanisms of VEGF and Ang1 on myocardium need to be evaluated. Three types of adenoviruses encoding human VEGF(165) (Ad-VEGF(165)), human angiopoietin-1 (Ad-Ang1) and green fluorescent protein (Ad-GFP, as a parallel control) were constructed. Experiments were taken both in vitro and in vivo. As in vitro, the antiapoptosis effect of VEGF(165), Ang1 and VEGF(165)+Ang1 on cardiac myoblasts was observed, which seemed to be related with the activation of phosphatidylinositol-3 kinase and Bcl-2 pathways. As in vivo, adenoviruses were intramyocardially injected immediately after the ligation of the left anterior descending coronay arteries in rats. The results showed positive effect of VEGF(165), Ang1 and VEGF(165)+Ang1 on decreasing the myocardial infarct size at the 7th day. Myocardial PI-3K activity and Bcl-2 expression were elevated relatively at the 3rd day. The protective effect of VEGF(165) and Ang1 on the myocardium may broaden their functional research and contribute to their clinical use in the future.

Dermal fibroblast-associated gene induction by asiaticoside shown in vitro by DNA microarray analysis

BACKGROUND

Asiaticoside, isolated from Centella asiatica, promotes fibroblast proliferation and extracellular matrix (ECM) synthesis in wound healing. The precise mechanism, however, in molecular and gene expression levels is still unclear.

OBJECTIVE

Using cDNA microarray technology, the alteration of gene expression profiles was determined for human dermal fibroblasts in vitro in the presence of asiaticoside (30 microg mL(-1)). Fifty-four genes, with known functions for cell proliferation, cell cycle progression and synthesis of ECM, were significantly upregulated in our 'genome-nest' expression profile at various time points. Furthermore, the mRNA levels and protein production of certain genes responsible for ECM synthesis (e.g. encoding type I and type III collagen proteins) were evaluated by Northern blot and radioimmunoassay, respectively.

RESULTS

We found that there is a close correlation between the gene profile, mRNA and protein production in the response of the cells to asiaticoside stimulation.

CONCLUSIONS

This information could be used for exploring the response of the target genes to asiaticoside in fibroblasts.

Animal models for cartilage reconstruction

Animal models are widely used to develop and evaluate tissue-engineering techniques for the reconstruction of damaged human articular cartilage. For the purpose of this review, these model systems will include in vitro culture of animal cells and explants, heterotopic models of chondrogenesis, and articular cartilage defect models. The objectives for these preclinical studies are to engineer articular cartilage for the functional restoration of a joint surface that appears anatomically, histologically, biologically, biochemically, and mechanically to resemble the original joint surface. While no animal model permits direct application to humans, each is capable of yielding principles on which decisions can be made that might eventually translate into a human application. Clearly, the use of animal models has and will continue to play a significant role in the advancement of this field. Each animal model has specific advantages and disadvantages. The key issue in the selection of an appropriate animal model is to match the model to the question being investigated and the hypothesis to be tested. The purpose of this review is to discuss issues regarding animal model selection, the benefits and limitations of these model systems, scaffold selection with emphasis on polymers, and evaluation of the tissue-engineered articular cartilage.

Identification of QTLs for weight and cross-sectional area on cervical enlargement of spinal cord in mice

Two inbred strains of mice, A/J, C57BL/6J and F2 intercross progenies,were used for QTL mapping for weight and cross-sectional area on cervical enlargement of spinal cord in mice. 13 QTLs located on Chromosome 2, 4, 8, 14, 15, 17, 18, 19 and X, respectively, for these two traits were found. Six QTLs were responsible for the cord weight, four for the cross-sectional area and three for both. Among 13 QTLs, three QTLs (P < 0.01) termed SC1 (located near D15Mit158) ,SC2 (DXMit140) and SC3 (DXMit64) accounted for 24%, 19% and 15% of the total variance in weight phenotype, and -3.78, 3.41 and 2.06 mg additive effect, respectively. The P value of other QTLs is between 0.01 and 0.05. SC1 is only one QTL that responsible for both weight and cross-sectional area in three QTLs above. This study revealed the location of major QTLs related size of spinal cord in mice, and may be helpful in fine mapping and ultimate identification of candidate genes.

Microdissection and molecular manipulation of single chromosomes in woody fruit trees with small chromosomes using pomelo (Citrus grandis) as a model. II. Cloning of resistance gene analogs from single chromosomes

Amplification of resistance gene analogs (RGAs) is both a useful method for acquiring DNA markers closely linked to disease resistance (R) genes and a potential approach for the rapid cloning of R genes in plants. However, the screening of target sequences from among the numerous amplified RGAs can be very laborious. The amplification of RGAs from specific chromosomes could greatly reduce the number of RGAs to be screened and, consequently, speed up the identification of target RGAs. We have developed two methods for amplifying RGAs from single chromosomes. Method 1 uses products of Sau3A linker adaptor-mediated PCR (LAM-PCR) from a single chromosome as the templates for RGA amplification, while Method 2 directly uses a single chromosomal DNA molecule as the template. Using a pair of degenerate primers designed on the basis of the conserved nucleotide-binding-site motifs in many R genes, RGAs were successfully amplified from single chromosomes of pomelo using both these methods. Sequencing and cluster analysis of RGA clones obtained from single chromosomes revealed the number, type and organization of R-gene clusters on the chromosomes. We suggest that Method 1 is suitable for analyzing chromosomes that are unidentifiable under a microscope, while Method 2 is more appropriate when chromosomes can be clearly identified.

Microdissection and molecular manipulation of single chromosomes in woody fruit trees with small chromosomes using pomelo (Citrus grandis) as a model. I. Construction of single chromosomal DNA libraries

Construction of single chromosomal DNA libraries by means of chromosome microdissection and microcloning will be useful for genomic research, especially for those species that have not been extensively studied genetically. Application of the technology of microdissection and microcloning to woody fruit plants has not been reported hitherto, largely due to the generally small sizes of metaphase chromosomes and the difficulty of chromosome preparation. The present study was performed to establish a method for single chromosome microdissection and microcloning in woody fruit species using pomelo as a model. The standard karyotype of a pomelo cultivar ( Citrus grandis cv. Guanxi) was established based on 20 prometaphase photomicrographs. According to the standard karyotype, chromosome 1 was identified and isolated with fine glass microneedles controlled by a micromanipulator. DNA fragments ranging from 0.3 kb to 2 kb were acquired from the isolated single chromosome 1 via two rounds of PCR mediated by Sau3A linker adaptors and then cloned into T-easy vectors to generate a DNA library of chromosome 1. Approximately 30,000 recombinant clones were obtained. Evaluation based on 108 randomly selected clones showed that the sizes of the cloned inserts varied from 0.5 kb to 1.5 kb with an average of 860 bp. Our research suggests that microdissection and microcloning of single small chromosomes in woody plants is feasible.

Animal models of spinal cord injury for evaluation of tissue engineering treatment strategies

Tissue engineering approaches to spinal cord injury (SCI) treatment are attractive because they allow for manipulation of native regeneration processes involved in restoration of the integrity and function of damaged tissue. A clinically relevant spinal cord regeneration animal model requires that the model mimics specific pathologic processes that occur in human SCI. This manuscript discusses issues related to preclinical testing of tissue engineering spinal cord regeneration strategies from a number of perspectives. This discussion includes diverse causes, pathology and functional consequences of human SCI, general and species related considerations, technical and animal care considerations, and data analysis methods.

Microvascular autologous submandibular gland transfer in severe cases of keratoconjunctivitis sicca

The objective is to evaluate the technique of microvascular autologous submandibular gland transfer for the treatment of severe keratoconjunctivitis sicca. From August 1999 to April 2002, 38 patients with severe keratoconjunctivitis sicca were treated by autologous submandibular gland transfer to the temporal region of the skull. The related vessels were anastomosed to the superficial temporal artery and vein. When the vein was too small, venous bridging was applied. Prior to cutting off the gland, the facial artery was preserved and infused with heparin in normal saline after the gland had been freed to allow inspection of the blood oozing from the three veins. This would be helpful in the selection of a relevant vein for anastomosis. Wharton's duct was transplanted to the upper lateral conjunctiva fornix, and the gland was left denervated. Postoperative scintigraphy with Tc99m pertechnetate, follow-up studies, and management of complications were performed. The transplantations were successful in 33 cases, their symptoms of xerophthalmia disappeared. The discomfort resulting from bright light and wind was also relieved. These patients could stop applying artificial tears. In five patients the transplanted glands did not survive. Epiphora occurred in eight cases. They were successfully treated by reducing the size of the graft. Obliteration of Wharton's duct took place in two cases and was treated by the reconstruction of the duct or duct orifice. Microvascular autologous submandibular gland transfer is a lasting and effective solution for severe cases of keratoconjunctivitis sicca.

Modulation of rabbit corneal epithelial cell proliferation by growth factor-regulated K(+) channel activity

We characterized the dependence of the mitogenic response by rabbit corneal epithelial (RCE) cells to serum containing growth factors on K(+) channel activation. Using both cell-attached and nystatin-perforated patch-clamp configurations, a K(+) channel was identified whose current-voltage relationship is linear with a single-channel conductance of 31 pS. Its activity was barely detectable following 24 h serum starvation. Exposure of starved cells to either 10% FBS, 5 ng/ml epidermal growth factor (EGF) or 2 n M endothelin-1 (ET-1) continuously increased its activity within 30 min by 40%, 54% and 29%, respectively. EGF and ET-1 in combination had additive effects on such activity. Application of 100 micro M 4-aminopyridine (4-AP), a K(+) channel blocker, inhibited serum-stimulated K(+) channel activity by 85%. DNA synthesis was markedly stimulated by serum, whereas incubation with either 4-AP (200 micro M) or Ba(2+) (1 m M) suppressed this increase by 51% and 23%, respectively, whereas 5 m M tetra ethyl ammonium (TEA) had no effect. Taken together, growth factor-induced increases in proliferation are dependent on K(+) channel stimulation. As the increases in K(+) channel activity induced by ET-1 and EGF were additive, these mitogens may stimulate K(+) channel activity through different signaling pathways linked to their cognate receptors.

EGF stimulates growth by enhancing capacitative calcium entry in corneal epithelial cells

In rabbit corneal epithelial cells (RCEC), we determined whether capacitative calcium entry (CCE) mediates the mitogenic response to epidermal growth factor, EGF. [Ca2+]i was measured with single-cell fluorescence imaging of fura2-loaded RCEC. EGF (5 ng/ml) maximally increased [Ca2+]i 4.4-fold. Following intracellular store (ICS) calcium depletion in calcium-free medium with 10 microM cyclopiazonic acid (CPA) (endoplasmic reticulum calcium ATPase inhibitor), calcium addback elicited plasma membrane Ca2+ influx as a result of activation of plasma membrane store operated channel (SOC) activity. Based on Mn2+ quench measurements of fura2 fluorescence, 5 ng/ml EGF enhanced such influx 2.3-fold, whereas with Rp-cAMPS (protein kinase A inhibitor) plus EGF it increased by 5.3-fold. In contrast, SOC activation was blocked with 100 microM 2-aminoethyldiphenylborate (2-APB, store-operated channel inhibitor). During exposure to either 50 microM UO126 (MEK-1/2 inhibitor) or 10 microM forskolin (adenylate cyclase activator), 5 ng/ml EGF failed to affect [Ca2+]i. RT-PCR detected gene expression of: 1) transient receptor potential (TRP) protein isoforms 1, 3, 4, 6 and 7; 2) IP3R isoforms 1-3. Immunocytochemistry, in conjunction with confocal and immunogold electron microscopy, detected plasma membrane localization of TRP4 expression. Inhibition of CCE with 2-APB and/or CPA, eliminated the 2.5-fold increase in intracellular [3H]-thymidine incorporation induced by EGF. Taken together, CCE in RCEC mediates the mitogenic response to EGF. EGF induces CCE through its stimulation of Erkl/2 activity, whereas PKA stimulation suppresses these effects of EGF. TRP4 may be a component of plasma membrane SOC activity, which is stimulated by ICS calcium depletion.

Age-related thymic involution in C57BL/6J x DBA/2J recombinant-inbred mice maps to mouse chromosomes 9 and 10

A comprehensive analysis of initial thymus size and involution rate has not been quantitated for different genetic backgrounds of mice, thus genetic linkage analysis of thymic involution has not been possible. Here, we have used a mathematical method to analyze the age-related decline in thymocyte count in C57BL/6 and DBA/2 mice and have observed that thymic involution could be best fit with a negative exponential curve N(t)=beta(0) x exp(-beta(1)t), where t represents the age (day). This regression model was applied to C57BL/6 x DBA/2 (B x D) recombinant inbred strains of mice to identify the genetic loci influencing age-related thymic involution. There was a dramatic genetic effect of B and D alleles on thymocyte count at young age and the age-related thymic involution rate. The strongest quantitative trait loci (QTL) influencing the rate of thymic involution were mapped to mouse chromosome (Chr) 9 (D9Mit20 at 62 cM) and Chr 10 (D10Mit61 at 32 cM). The strongest QTLs influencing the initial thymocyte count were mapped to ChrX (DXMit324 at 26.5 cM) and Chr 3 (D3Mit127 at 70.3 cM). The present study suggests that the initial thymus size and the rate of thymic involution may be influenced by a relatively small number of genetic loci.

Tunneling into multiwalled carbon nanotubes: coulomb blockade and the Fano resonance

Tunneling spectroscopy measurements of single tunnel junctions formed between multiwalled carbon nanotubes (MWNTs) and a normal metal are reported. Intrinsic Coulomb interactions in the MWNTs give rise to a strong zero-bias suppression of a tunneling density of states that can be fitted numerically to the environmental quantum-fluctuation theory. An asymmetric conductance anomaly near zero bias is found at low temperatures and interpreted as Fano resonance in the strong tunneling regime.

Liver tolerance mediated by antigen presenting cells: fact or fiction?

Possible mechanisms by which liver antigen presenting cells (APC) may facilitate tolerance induction are discussed. Tolerance may be facilitated by a distinctive combination of factors, linked to the unique anatomical and microenvironmental features of the liver.