Association of autoantibody specificity and response to intravenous immunoglobulin G therapy in immune thrombocytopenia: a multicenter cohort study

BACKGROUND

Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder, in which platelet glycoprotein (GP)IIb-IIIa and GPIb-IX are the two most frequently targeted autoantigens. Our previous studies in animal models of ITP demonstrated that intravenous immunoglobulin G (IVIG) could protect against anti-GPIIb-IIIa autoantibody-mediated thrombocytopenia but failed to ameliorate ITP induced by most anti-GPIb-IX autoantibodies.

OBJECTIVES

The objective of this human study was to evaluate the association between the specificity of antiplatelet autoantibodies and response to IVIG treatment.

PATIENTS/METHODS

In this retrospective study, a cohort of 156 previously untreated adults with severe ITP who underwent IVIG therapy (0.4 g kg(-1)  day(-1) for 5 days) was analyzed. The primary outcome was response defined as platelet counts of ≥ 30 × 10(9)  L(-1) and a doubling of baseline counts within 7 days of dosing, and an absence of bleeding.

RESULTS AND CONCLUSIONS

Among the 66 patients with anti-GPIb-IX autoantibodies, only 24 (36.4%) achieved a response, as compared with 72 of 90 patients (80.0%) who were negative for anti-GPIb-IX autoantibodies (relative risk 2.2; 95% confidence interval 1.6-3.1). This study found no difference in response between patients with anti-GPIIb-IIIa autoantibodies (61.7%) and those without anti-GPIIb-IIIa autoantibodies (61.3%). Logistic regressions, including main effects and the interaction between these two autoantibodies, showed no influence of anti-GPIIb-IIIa autoantibodies on the effects of anti-GPIb-IX autoantibodies with regard to their association with IVIG response. Thus, in adults with ITP, the presence of anti-GPIb-IX autoantibodies is a predictive factor for poor response to IVIG treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01666795.

The use of a covered stent graft for obliteration of high-flow carotid cavernous fistula presenting with life-threatening epistaxis

BACKGROUND

We present a rare complication of trans-sphenoidal adenectomy (TSA) for pituitary macroadenoma: carotid cavernous fistula (CCF) that was treated with endovascular therapy. The incidence of internal carotid artery (ICA) injury following TSA is 1% and may spontaneously heal by packing and rarely manifest as symptomatic CCF/aneurysm. Treatment of post-TSA CCF may be challenging due to the breach of nasal floor and may be prone to recurrence.

PRESENTATION/INTERVENTION

Uncontrolled intra-operative bleeding during a TSA led to an emergent angiogram to show slow-flow left CCF. Due to clinical deterioration with nasal bleeding, angiography was repeated after 4 h; the fistula had transformed into high flow with significant increase in size, and was therefore embolized using stent-assisted coiling. The fistula recanalized in a month with massive epistaxis and was re-treated using a covered stent graft.

CONCLUSION

This case represents several unique learning points: (1) CCF as a complication of TSA due to close anatomical proximity; (2) the role of endovascular management post-TSA complication; (3) stent-assisted coil embolization of high-flow fistula with moderate ICA laceration; (4) recanalization of CCF causing massive epistaxis; (5) rare use of covered stent graft stent in distal intracranial circulation maintaining integrity and patency of ICA; (6) long-term results after covered stent graft with no in-stent restenosis.

Design and initial operation of multichord soft x-ray detection arrays on the STOR-M tokamak

Two miniature pinhole camera arrays for spatially and temporally resolved measurements of soft x-ray emission have been designed and installed on the STOR-M tokamak. Each array consists of a photodiode array, with one array viewing vertically and one viewing horizontally through a plasma cross section. Preamplifiers with fixed gains of 10(5) VA and custom built amplifiers with variable gains are used for signal amplification. Digitizers with 14 bit resolution and 3 MSs sampling rate are used for data acquisition. In the initial operation, an Al foil with a thickness of 1.8 microm installed for one array and Be filter of 7.6 microm installed for the other array are used to test signal strength. Initial tests have identified sawtooth oscillations and 20 kHz fluctuations, which are also detected by Mirnov coils, superimposed on the sawtooth oscillations.

Peroxynitrite mediates high glucose-induced osteoblast apoptosis

High glucose (HG) state is closely related to diabetic complications, and among these one main pathogenesis involves apoptosis of important functional cells. However, the mechanism of osteoblast (OB) apoptosis induced by HG state is not clear. Peroxynitrite (ONOO-), the strongest oxidant, can mediate apoptosis in various kinds of cells, including OB. Therefore, this study was aimed at investigating whether HG state could induce OB apoptosis through ONOO-. Cultured OB from rat calvariae explanted from E21 fetuses were treated with HG solution. The ratio of OB apoptosis and ONOOcontent was assayed by TUNEL, flow cytometry, and immunohistochemistry. The results showed that HG state could induce ONOO- overformation (p<0.01), and excessive OB apoptosis (p<0.001). However, the HG-induced OB apoptosis could be attenuated by peonol, a potent scavenger of ONOO-. In conclusion, HG state might trigger excessive ONOO- formation, mediating OB apoptosis.

Impact of Lotensin and Salviae on the changes of TGF-beta1 and its receptors in a rat model of chronic cyclosporine-induced nephropathy

OBJECTIVES

Transforming growth factor-beta(1) (TGF-beta(1)) and its receptors, type 1 (TR-1) and type 2 (TR-2) play important roles in chronic cyclosporine (CsA)-induced nephropathy. Lotensin is known as an angiotensin-converting enzyme inhibitor and may reduce chronic CsA-induced nephropathy. Recently it is reported that Salviae (a Chinese medicine), which can improve microcirculation and decrease the expression of TGF-beta(1) has the same effect as that of lotensin. Therefore, in this study we assessed the effects of Lotensin or Salviae on the chronic CsA-induced upregulation of TGF-beta(1), TR-1, and TR-2 in a rat model.

MATERIALS AND METHODS

Sodium-depleted rats were administered CsA by gastric gavage and a new rat model of chronic CsA-induced nephropathy was established. Rats with chronic CsA-induced nephropathy were treated by lotensin or Salviae. The proteins of TGF-beta(1), TR-1, and TR-2, and the mRNA of TR-1 and TR-2 in the kidneys of CsA-treated rats, were measured by immunohistochemistry (IHC) and in situ hybridization (ISH). The results were investigated semiquantitatively by image analysis.

RESULTS

Lotensin or Salviae individually attenuated CsA-induced nephropathy in the rat models, and downregulated the protein expressions of TGF-beta(1), TR-1, and TR-2, and the mRNA transcripts of TR-1 and TR-2 in the rat model.

CONCLUSION

Our studies show that treatment with lotensin or Salviae is useful in preventing chronic CsA-induced nephropothy.

Superior ex vivo cord blood expansion following co-culture with bone marrow-derived mesenchymal stem cells

One factor limiting the therapeutic efficacy of cord blood (CB) hematopoietic progenitor cell (HPC) transplantation is the low cell dose of the graft. This is associated with an increased incidence of delayed or failed engraftment. Cell dose can be increased and the efficacy of CB transplantation potentially improved, by ex vivo CB expansion before transplantation. Two ex vivo CB expansion techniques were compared: (1) CD133+ selection followed by ex vivo liquid culture and (2) co-culture of unmanipulated CB with bone-marrow-derived mesenchymal stem cells (MSCs). Ex vivo culture was performed in medium supplemented with granulocyte colony-stimulating factor, stem cell factor and either thrombopoietin or megakaryocyte growth and differentiation factor. Expansion was followed by measuring total nucleated cell (TNC), CD133+ and CD34+ cell, colony-forming unit and cobblestone area-forming cell output. When compared to liquid culture, CB-MSC co-culture (i) required less cell manipulation resulting in less initial HPC loss and (ii) markedly improved TNC and HPC output. CB-MSC co-culture therefore holds promise for improving engraftment kinetics in CB transplant recipients.

A novel triple purge strategy for eliminating chronic myelogenous leukemia (CML) cells from autografts

Imatinib-refractory chronic myelogenous leukemia (CML) patients can experience long-term disease-free survival with myeloablative therapy and allogeneic hematopoietic cell transplantation; however, associated complications carry a significant risk of mortality. Transplantation of autologous hematopoietic cells has a reduced risk of complications, but residual tumor cells in the autograft may contribute to relapse. Development of methods for purging tumor cells that do not compromise the engraftment potential of the normal hematopoietic cells in the autograft has been a long-standing goal. Since primitive CML cells differentiate more rapidly in vitro than their normal counterparts and are also preferentially killed by mafosfamide and imatinib, we examined the purging effectiveness on CD34(+) CML cells using a strategy that combines a brief exposure to imatinib (0.5-1.0 microM for 72 h) and then mafosfamide (30-90 microg/ml for 30 min) followed by 2 weeks in culture with cytokines (100 ng/ml each of stem cell factor, granulocyte colony-stimulating factor and thrombopoietin). Treatment with 1.0 microM imatinib, 60 microg/ml mafosfamide and 14 days of culture with cytokines eliminated BCR-ABL(+) cells from chronic phase CML patient aphereses, while preserving normal progenitors. This novel purging strategy may offer a new approach to improving the effectiveness of autologous transplantation in imatinib-refractory CML patients.

Ex vivo expansion of umbilical cord blood

The efficacy of cord blood (CB) transplantation is limited by the low cell dose available. Low cell doses at transplant are correlated with delayed engraftment, prolonged neutropenia and thrombocytopenia and elevated risk of graft failure. To potentially improve the efficacy of CB transplantation, approaches have been taken to increase the cell dose available. One approach is the transplantation of multiple cord units, another the use of ex vivo expansion. Evidence for a functional and phenotypic heterogeneity exists within the HSC population and one concern associated with ex vivo expansion is that the expansion of lower 'quality' hematopoietic progenitor cells (HPC) occurs at the expense of higher 'quality' HPC, thereby impacting the reserve of the graft. There is evidence that this is a valid concern while other evidence suggests that higher quality HPC are preserved and not exhausted. Currently, ex vivo expansion processes include: (1) liquid expansion: CD34+ or CD133+ cells are selected and cultured in medium containing factors targeting the proliferation and self-renewal of primitive hematopoietic progenitors; (2) co-culture expansion: unmanipulated CB cells are cultured with stromal components of the hematopoietic microenvironment, specifically mesenchymal stem cells (MSC), in medium containing growth factors; and (3) continuous perfusion: CB HPC are cultured with growth factors in 'bioreactors' rather than in static cultures. These approaches are discussed. Ultimately, the goal of ex vivo expansion is to increase the available dose of the CB cells responsible for successful engraftment, thereby reducing the time to engraftment and reducing the risk of graft failure.

SNPkit: an efficient approach to systematic evaluation of candidate single nucleotide polymorphisms in public databases

There is widespread interest in devising genotyping methods for SNPs that are robust, inexpensive, and simple to perform. Although several high-throughput SNP genotyping technologies have been developed, including the oligonucleotide ligation assay, real-time PCR, and mass spectrometry, the issues of simplicity and cost-effectiveness have not been adequately addressed. Here we describe the application of a novel computer software package, SNPkit, which designs SNP genotyping assays based on a classical approach for discriminating alleles, restriction enzyme digestion. SNPkit can be used in genotyping assays for almost any SNPs including those that do not alter "natural" restriction sites. Using this method, 164 SNPs have been evaluated in DNA samples from 48 immortalized cell lines of randomly selected Chinese subjects. Sixty-two (37.8%) of the SNPs appeared to be common (frequencies of the minor alleles are > or = 5%) and were subsequently applied to a larger population-based sample. Overall, by using SNPkit, we have been able to validate and genotype accurately a large fraction of publicly available SNPs without sophisticated instrumentation.

Candidate genes for osteoporosis. Therapeutic implications

Osteoporosis, which afflicts 10 million Americans, is a complex disease characterized by decreased bone mass, microarchitectural deterioration of bone tissue, and an increase in fracture risk. Family and twin studies have established a genetic contribution to the etiology of osteoporosis. The biological candidate genes of osteoporosis can be ordered into 5 categories: (i) calcium homeostasis; (ii) hormonal dysfunction; (iii) osteoblast and osteoclast development and regulation; (vi) cartilage matrix metabolism; and (v) lipoprotein metabolism. In addition, genome-wide scans have identified a number of chromosomal regions harboring genes that influence bone mineral density. Moreover, the drug responses to various treatments of osteoporosis are reported to be modulated by DNA polymorphisms of the vitamin D receptor gene, the estrogen receptor 1 gene, and the transforming growth factor beta 1 gene. With the rapid advancement of the Human Genome Project and biotechnology, it will be possible to carry out parallel analyses of large numbers of candidate genes for osteoporosis and to calculate a patient's individual fracture risk in the context of specific environmental influences. This will eventually lead to more advanced diagnostic methods and more efficacious drugs targeting osteoporosis.

A gene therapy for cancer based on the angiogenesis inhibitor, vasostatin

The growth and persistence of solid tumors and their metastasis are angiogenesis-dependent. Vasostatin, the N-terminal domain of calreticulin inclusive of amino acids 1-180, is a potent angiogenesis inhibitor. To investigate whether intramuscular administration of vasostatin gene has the antitumor activity in mouse tumor models, we constructed a plasmid DNA encoding vasostatin and a control vector. Production and secretion of vasostatin protein by COS cells transfected with the plasmid DNA encoding vasostatin (pSecTag2B-vaso) were confirmed by Western blot analysis and ELISA. Conditioned medium from vasostatin-transfected COS cells apparently inhibited human umbilical vein endothelial cell (HUVEC) and mouse endothelial cell (SVEC4-10) proliferation, compared with conditioned medium from the COS cells transfected with control vector or non-transfected cells. Treatment with pSecTag2B-vaso twice weekly for 4 weeks resulted in the inhibition of tumor growth and the prolongation of the survival of tumor-bearing mice. The sustained high level of vasostatin protein in serum could be identified in ELISA. Angiogenesis was apparently inhibited in tumor by immunohistochemical analysis. Angiogenesis was also inhibited in the chicken embryo CAM assay and mouse corneal micropocket assay. The increased apoptotic cells were found within the tumor tissues from the mice treated with plasmid DNA encoding vasostatin. Taken together, the data in the present study indicate that the cancer gene therapy by the intramuscular delivery of plasmid DNA encoding vasostatin, is effective in the inhibition of the systemic angiogenesis and tumor growth in murine models. The present findings also provide further evidence of the anti-tumor effects of the vasostatin, and may be of importance for the further exploration of the application of this molecule in the treatment of cancer.

Relation between the flexibility of the WPD loop and the activity of the catalytic domain of protein tyrosine phosphatase SHP-1

The conserved WPD loop of protein tyrosine phosphatases play an important role in the catalytic activity and the invariant aspartate residue acts as a general acid/base catalyst in the dephosphorylation reaction. In our previous report, we have demonstrated that the catalytic activities of the PTPs are influenced by the flexibility and stability of the WPD loop in its active "open" conformation [Yang et al., 1998]. Phosphatases with a more flexible WPD loop generally have higher specific activity. In this report, we modify the WPD loop of SHP-1 by alanine-scan mutation of the residues flanking the loop and measure their effects on the catalytic activity of the phosphatase. We show that the S418A, V424A, S426A, E427A, and P428A mutants increase the phosphatase activity, possibly due to the increased flexibility of the WPD loop, whereas the L417A, L417G and P425A mutants decrease its phosphatase activity. In addition, we propose that the two-proline residues in the WPD loop (Pro(420) and Pro(425) in SHP-1) work as pivotal points through a conserved hydrophobic network and allows residues between the pivotal points to have maximum flexibility in enhancing the phosphatase activity. Furthermore, our data suggest that the hydrolysis of the phosphoryl-cysteine intermediate, not its formation, is the rate-limiting step with p-nitrophenyl phosphate as the substrate while both the steps are rate-limiting with phosphotyrosine as the substrate.

The association between PPP1R3 gene polymorphisms and type 2 diabetes mellitus

OBJECTIVE

To detect the relationship between the polymorphism of the glycogen-targeting regulatory subunit of the skeletal muscle glycogen-associated protein phosphatase 1 (PPP1R3) gene and type 2 diabetes by case-control study.

METHODS

We genotyped the PPP1R3 gene Asp905Tyr polymorphism and a common 3'-untranslated region AT (AU)-rich element (ARE) polymorphism in 101 type 2 diabetic patients and 101 controls by oligonucleotide ligation assay (OLA) and polyacrylamide gel elecrophoresis, respectively.

RESULTS

Subjects with Tyr/Tyr genotypes whose body mass index (BMI) < 25 were used as the reference group. Those whose BMI > or = 25 with Asp905 had a 3.66-fold increase (95% CI: 1.48-9.06, P = 0.005) in type 2 diabetes risk. No association was found between 3'UTR ARE polymorphism and type 2 diabetes mellitus (OR = 1.15; 95% CI: 0.62-2.14, P = 0.65).

CONCLUSION

A joint effect between the Asp905 and BMI increases the risk of type 2 diabetes, and Asp905Tyr and ARE polymorphism of PPP1R3 gene are not the major diabetogenic gene variants in Chinese population.

[The effects of thrombopoietin and interleukin-11 on bone marrow megakaryocytic progenitors in patients with chronic idiopathic thrombocytopenic purpura in vitro]

OBJECTIVE

To observe the effects of recombinant human thrombopoietin (rhTPO) and rhTPO in combination with recombinant human interleukin-11(rhIL-11) on the megakaryocyte (MK) colony growth and maturation in patients with chronic idiopathic thrombocytopenic purpura (CITP) in vitro.

METHODS

Bone marrow (BM) mononuclear cells of 21 patients with CITP were cultured in plasma clot culture systems, to which were added rhTPO alone or rhTPO plus rhIL-11 over a range of concentrations. After 14 days, the MK colonies were stained by GP III a Mc Ab(SZ-21) and ABC-Kit and counted. The diameters and areas of the positive cells of GP III a were measured by BM-cell analysis system of MCDS-2010.

RESULTS

The diameters and areas of MK in CITP group were significantly lower than that in control group, P < 0.05. The addition of rhTPO to culture systems increased CFU-MK, total colonies and diameters and areas of MK in CITP patients. And this promoting effect was not dose-dependent. The optimal concentration of rhTPO was 10 ng/ml; in the group where 10 ng/ml rhTPO was used in combination with 20 ng/ml rhIL-11, the counts of CFU-MK, total colonies and the measurements of areas and diameters of MK increased significantly, compared with those in the group where rhTPO was used alone.

CONCLUSION

There are maturation dysfunctions of MK progenitors in patients with CITP. rhTPO alone or in combination with rhIL-11 can promote the proliferation and maturation of MK progenitors in patients with CITP and, moreover, the combination of the two cytokines has more significant promoting effects, compared to rhTPO alone.

Immunogene therapy of tumors with vaccine based on Xenopus homologous vascular endothelial growth factor as a model antigen

Overcoming immune tolerance of the growth factors associated with tumor growth should be a useful approach to cancer therapy by active immunity. We used vascular endothelial growth factor (VEGF) as a model antigen to explore the feasibility of the immunogene tumor therapy with a vaccine based on a single xenogeneic homologous gene, targeting the growth factors associated with angiogenesis. To test this concept, we constructed a plasmid DNA encoding Xenopus homologous VEGF (XVEGF-p) and control vectors. We found that immunogene tumor therapy with a vaccine based on XVEGF was effective at both protective and therapeutic antitumor immunity in several tumor models in mice. VEGF-specific autoantibodies in sera of mice immunized with XVEGF-p could be found in Western blotting analysis and ELISA assay. The purified immunoglobulins were effective at the inhibition of VEGF-mediated endothelial cell proliferation in vitro, and at antitumor activity and the inhibition of angiogenesis by adoptive transfer in vivo. The elevation of VEGF in the sera of the tumor-bearing mice could be abrogated with XVEGF-p immunization. The antitumor activity and production of VEGF-specific autoantibodies, significantly elevated IgG1 and IgG2b, could be abrogated by the depletion of CD4(+) T lymphocytes. The observations may provide a vaccine strategy for cancer therapy through the induction of autoimmunity against the growth factors associated with tumor growth in a cross reaction with single xenogeneic homologous gene and may be of importance in the further exploration of the applications of other xenogeneic homologous genes identified in human and other animal genome sequence projects in cancer therapy.

Statistical considerations for genome-wide scans: design and application of a novel software package POLYMORPHISM

OBJECTIVE

Given the cost and complexity of genome-wide scans, optimization of study design is of critical importance. Available algorithms only partially satisfy this need. We designed a software package called 'POLYMORPHISM' to meet these needs.

METHODS

The program is designed to calculate linkage parameters for both 'single-point' and 'two-point' settings that are applicable also to incompletely informative microsatellite markers. In single-point analysis, the heterozygosity, polymorphism information content (PIC) and linkage information content (LIC) statistics based on marker allele frequencies are provided. In two-point analysis, joint PIC values for two markers, the conditional probability of detecting linkage phase, the frequency of double heterozygotes and the expected number of informative meioses are calculated.

RESULTS

Results were obtained using S.A.G.E./DESPAIR (Design of Linkage Studies Based on Pairs of Relatives) in addition to applying this program to a Centre d'Etude du Polymorphisme pedigree-derived genotyping data set, which estimated critical parameters used in a two-stage genome scan. A single nucleotide polymorphism (SNP)-based one-stage genomic screen strategy is also considered.

CONCLUSIONS

LIC values are crucial for getting accurate estimates on those parameters that are important for a two-stage genome screening study. Optimization of the cost-effectiveness of an SNP-based genomic screen strategy is possible by modeling a balance between marker information content and marker density.

Molecular epidemiology of preterm delivery: methodology and challenges

Preterm delivery (PTD) appears to be a complex trait determined by both genetic and environmental factors. Few studies have examined genetic influence on PTD. The overall goal of our study is to examine major candidate genes of PTD and to test gene-environment interactions. Our study includes 500 preterm trios, including 500 preterm babies and their parents and 500 maternal age-matched term controls. We will perform the transmission/disequilibrium test (TDT) on candidate genes thought to be important in each of the four biological pathways of PTD: (1) decidual chorioamionotic inflammation: interleukin 1 (IL-1), IL-6, and tumour necrosis factor (TNF); (2) maternal and fetal stress: corticotropin-releasing hormone (CRH); (3) uteroplacental vascular lesions: methylenetereahydrofolate reductase (MTHFR); and (4) susceptibility to environmental toxins: GSTM1, GSTT1, CYP1A1, CYP2D6, CYP2E1, NAT2, NQO1, ALDH2, and EPHX. We will also perform standard case-control analyses on the 500 preterm cases and 500 term controls to examine gene-environment interactions. The major environmental, nutritional and social factors as well as clinical variables known or suspected to be associated with PTD will be used to test for gene-environment interactions. This study integrates epidemiological and clinical data as well as genetic markers along major pathogenic pathways of PTD. The findings from this study should improve our understanding of genetic influences on PTD and gene-environment interactions.

Association of asthma with beta(2)-adrenergic receptor gene polymorphism and cigarette smoking

Recent studies have suggested that two polymorphisms of the beta(2)-adrenergic receptor (beta(2)AR) gene at codons 16 (arginine to glycine) and 27 (glutamine to glutamate) affect an individual's airway responsiveness, or response to acute or chronic beta(2)-agonist therapy but are not risk factors for asthma. We hypothesize that there is an interaction effect on asthma between the beta(2)AR gene polymorphisms and cigarette smoking. A case-control study was conducted in 128 asthma cases and 136 control individuals identified from 10,014 studied subjects in rural Anqing, China. Allele-specific polymerase chain reaction (PCR) was used to genotype beta(2)AR gene polymorphisms. Multiple logistic regression was used to adjust for potential confounding factors. We found a marginally significant interaction between cigarette smoking and beta(2)AR-16 genotype after adjusting for important confounding factors (p = 0.06). Specifically, we found that compared with never-smoking Gly-16 homozygotes, those ever-smokers who are Arg-16 homozygotes had a significantly increased risk of asthma (odds ratio [OR] = 7.81; 95% confidence interval [CI]: 2.07 to 29.5). This association showed a clear dose-response relationship with the number of cigarettes smoked. However, there was no significant association of asthma with polymorphisms of the beta(2)AR at position 27 (OR = 1.38; 95% CI: 0.69 to 2.73). Our study suggests a gene-environment interaction between the Arg-16 genotype and ever cigarette smoking with respect to the susceptibility of an individual to asthma.

Protein tyrosine phosphatase SHP-1 specifically recognizes C-terminal residues of its substrates via helix alpha0

The catalytic domain of protein tyrosine phosphatase SHP-1 possesses distinct substrate specificity. It recognizes the P-3 to P-5 residues of its substrates via the beta5-loop-beta6 region. To study the substrate specificity further, we determined the structure of the catalytic domain of SHP-1 (C455S) complexed with a less-favorable-substrate peptide originated from SIRPalpha. The complex has disordered N-terminal peptide structure and reduced interactions between the N-terminal peptide and the beta5-loop-beta6 region. This could be the basis for the lower affinity of peptide pY(427) for the catalytic domain of SHP-1. In addition, by comparing the SHP-1/less-favorable peptide complex structure with the SHP-1/substrate complex structures, we identified a novel substrate-recognition site in the catalytic domain of SHP-1. This site was formed by helix alpha0 and the alpha5-loop-alpha6 motif of SHP-1, and specifically bound residues at the P + 4 and further C-terminal positions of peptide substrates.

Detection of novel ALAD gene polymorphisms using denaturing high-performance liquid chromatography

Denaturing high-performance liquid chromatography (DH-PLC), which is based on the separation of mismatched DNA heteroduplexes, is one of the most promising techniques for detecting nucleotide polymorphisms. Lead is an important environmental toxicant that can impair the cardiovascular, central nervous, renal, reproductive, and hematologic systems. Here we compare the sensitivity and efficiency of DNA polymorphism detection in the delta-aminolevulinate dehydratase (ALAD) gene encoding the principal lead-binding protein in humans by means of DHPLC and direct DNA sequencing of polymerase chain reaction amplicons. In a sample of 48 unrelated Chinese women, five novel mutations were discovered in intron 6 (G13298C). exon 7 (C13348T), intron 8 (C13847T), intron 12 (C15096T), and the 3' untranslated region of exon 13 (A15762C). The allele frequencies of C13298, T13348, T13847, T15096, and C15762 alleles were 21.3%, 2.3%. 82.1%, 62.5%, and 1.1%, respectively. All five mutations were detected by both DHPLC and direct DNA sequencing. No previously reported missense ALAD mutations were found in this Chinese population. Our study confirms that DHPLC provides an accurate method for the rapid identification of single nucleotide polymorphisms.

Association of airway responsiveness with asthma and persistent wheeze in a Chinese population

STUDY OBJECTIVES

Data from a cross-sectional study were analyzed to examine the association of increased airway responsiveness with physician-diagnosed asthma and persistent wheeze.

DESIGN

Two methods for calculating the provocative dose that decreases the airflow rate by 20% (PD(20)) were used as indexes for increased airway responsiveness: (1) a 20% drop in FEV(1) calculated from baseline FEV(1) (PD(20)b), and (2) a 20% drop in FEV(1) from FEV(1) measurements after inhalation of saline solution (PD(20)s). Both PD(20)b and PD(20)s were measured through induction by varying doses of methacholine.

SETTING

Anqing, Anhui Province, China.

PARTICIPANTS

Study subjects were 8 to 74 years of age and were classified into four groups: children (< 15 years old), young adults (15 to 29 years old), adults (30 to 44 years old), and older adults (> or 5 years old).

INTERVENTIONS

The differences in estimated odds ratios of airway hyperresponsiveness with asthma and wheeze, sensitivity and specificity, and coefficients of variation were compared between PD(20)b and PD(20)s. The sample for analysis consisted of 10,284 subjects from 2,663 nuclear families with complete data on wheeze, asthma, and major potential confounding factors.

MEASUREMENTS AND RESULTS

The prevalence of asthma in this sample was lowest in subjects with no demonstrable PD(20) and had a reverse dose-response relationship with PD(20) across all age groups. Using the receiver operating characteristic, the sensitivity and specificity of the PD(20)s or PD(20)b were found to be almost identical. A similar trend was found for persistent wheeze, although the estimated odds ratios for persistent wheeze appeared slightly smaller than those for physician-diagnosed asthma.

CONCLUSIONS

This study demonstrates a dose-response relationship between increased airway responsiveness and asthma and wheeze in this Chinese population. PD(20)s or PD(20)b yielded virtually indistinguishable results, which indicated that either of the two tests could serve as an index of airway hyperresponsiveness.

Metabolic gene polymorphisms and risk of dysmenorrhea

We conducted a molecular epidemiologic study in rural China to investigate the association of the cytochrome P450 2D6 (CYP2D6) and glutathione S-transferase Mu (GSTM1) polymorphisms with dysmenorrhea. This report includes 435 subjects, 129 with and 306 without any history of dysmenorrhea, who did not smoke or drink alcohol. We obtained information on dysmenorrhea and major covariates by questionnaire interview. We used categorical methods and logistic regression models to evaluate the individual and combined associations of CYP2D6 and GSTM1 polymorphisms with dysmenorrhea and its subgroups, occasional (N = 70) and recurrent (N = 59), with adjustment for age, education, occupation, passive smoke exposure, age of menarche, parity, contraceptive method, height, and body mass index. Both variant CYP2D6 and GSTM1 genotypes were associated with increased risk of recurrent dysmenorrhea [for CYP2D6, odds ratio (OR) = 1.7 and 95% confidence interval (95% CI) = 0.9-3.1; for GSTM1, OR = 1.8 and 95% CI = 1.0-3.4). There was no appreciable association between these variant genotypes and occasional dysmenorrhea. When both the CYP2D6 and GSTM1 genotypes were considered together, the highest risk of recurrent dysmenorrhea was found among women with variant genotypes in both CYP2D6 and GSTM1 (OR = 3.1; 95% CI = 1.2-8.0). This study provides evidence of genetic susceptibility to recurrent dysmenorrhea.

Familial aggregation of bronchodilator response: a community-based study

We investigated familial aggregation of bronchodilator response (BDR) among 4,946 subjects selected from 1,161 index families with asthma in a rural community in China. Each family unit consisted of both parents and their first and subsequent offspring, aged 8-20. Raw BDR measurements, defined as the percentage change in FEV(1) after 180 microg of albuterol, were adjusted to account for sex, age, height, weight, education, smoking, asthma, wheeze, and allergy status. Using these adjusted BDR values, we found significant correlation for father-first offspring pairs, mother-first offspring pairs, mother-subsequent offspring pairs, and first offspring-subsequent offspring pairs. The overall magnitude of the correlation coefficient (0.088-0.165) suggests a modest degree of familial clustering. The largest odds ratio was seen for subsequent offspring who had mothers and first offspring with adjusted BDR values above the median: 3.10 (95% CI: 1.85-5.20) in these index families with asthma. Thus, our data support a significant familial aggregation of BDR in this Chinese population, which points to a role of genetic factors in BDR.

[Long-term observation of curative effects of posterior scleral reinforcement surgery in patients with juvenile progressive myopia]

OBJECTIVE

To evaluate the long-term curative effects of the scleral reinforcement surgery in juvenile progressive myopia.

METHOD

25 patients (34 eyes) with the disease (average age, 17.12 +/- 7.47 years old) were observed for 3 to 5 years after posterior scleral reinforcement surgery.

RESULTS

The naked visual acuities at postoperative one and three years were better than that before the operation (P < 0.01). The average axial elongation in the first, third and fifth year after the operation was 0.098 mm/year, 0.073 5 mm/year and 0.115 mm/year, respectively; the increment of refractive diopter was smaller than 0.50 D/year.

CONCLUSION

The scleral reinforcement surgery is a safe and effective treatment for juvenile progressive myopia.

Genetic susceptibility to benzene and shortened gestation: evidence of gene-environment interaction

This study investigated whether the association between low level benzene exposure and shortened gestation is modified by two susceptibility genes, CYP1A1 and GSTT1. This report includes 542 (302 nonexposed, 240 benzene-exposed) nonsmoking and nondrinking mothers of singleton live births at Beijing Yanshan Petrochemical Corporation between June 1995 and June 1997. Epidemiologic and clinical data and blood samples were obtained from mothers. Multiple linear regression models were used to estimate the associations of benzene exposure and genetic susceptibility with gestational age, adjusting for maternal age, education, parity, stress, passive smoking, prepregnancy weight and height, and infant's sex. Without consideration of genotype, benzene exposure was associated with a decrease in mean gestational age of 0.29 (standard error (SE), 0.12) week. When stratified by the maternal CYP1A1 genotype, the estimated decrease was 0.54 (SE, 0.12) week for the AA group, which was significantly greater (p = 0.003) than that for the Aa/aa group, which showed no decrease in gestational age. When both CYP1A1 and GSTT1 were considered, the greatest decrease was found among exposed mothers with the CYP1A1 AA-GSTT1 absent group (0.79 (SE, 0.25) week) and the CYP1A1 AA-GSTT1 present group (0.50 (SE, 0.22) week). Among the nonexposed, genetic susceptibility alone did not confer a significant adverse effect. This study provides evidence of gene-environment interaction and supports further assessment of the role of genetic susceptibility in the evaluation of reproductive toxins.

[Clinical study on interferon treatment of chronic idiopathic thrombocytopenic purpura]

The efficacy and mechanism of interferon alpha-2a (IFN alpha-2a) were assessed in the treatment of chronic idiopathic thrombocytopenic purpura (cITP). 20 patients with cITP (treatment group) were treated with IFN alpha-2a 3MIU i.m. once a week for 8 weeks; 28 patients with cITP (control group) were treated with prednisone 1 mg/(kg.d) for 4 weeks. Blood platelet counts (BPC), megakaryocyte number, immunnological parameters, percent and absolute counts of reticulated platelets (RPs) and megakaryocyte colony formation units were observed before and after therapy. The results showed that the efficacy of IFN alpha-2a was better than that of corticosteroid, P < 0.05. The RPs% decreased and the platelet-producing megakaryocyte percentage increased from 11.43% to 33.19% significantly after IFN alpha-2a therapy, but there were no significant changes in immunnological parameters. These indicate that IFN alpha-2a is effective in treating cITP, the mechanism may be based on promoting the megakaryocyte development and activating the production of platelets.

A 500-kb region on chromosome 16p13.1 contains the pseudoxanthoma elasticum locus: high-resolution mapping and genomic structure

We have recently mapped the genetic defect underlying pseudoxanthoma elasticum (PXE), an inherited disorder characterized by progressive calcification of elastic fibers in skin, eye, and cardiovascular system, to chromosome 16p 13.1. Here we report further data on the fine-mapping and genomic structure of this locus. Haplotype analysis of informative PXE families narrowed the locus to an interval of less than 500 kb located between markers D16B9621 and D16S764. Three overlapping YAC clones were found to cover this region through YAC-STS content mapping. An overlapping BAC contig was then constructed to cover this interval and the surrounding region. About 80% of this chromosomal region has been fully sequenced using the BAC shotgun technique. Gene content and sequence analysis predicted four genes (MRP1, MRP6, PM5, and a novel transcript) and two pseudogenes (ARA and PKDI) within this interval. By screening a somatic cell hybrid panel we were able to precision-map the breakpoint of Cy185 and the starting point of a chromosomal duplication within 20 kb of BAC A962B4. The present data further refine the localization of PXE, provide additional physical cloning resources, and will aid in the eventual identification of the genetic defect causing PXE.

[Terminal differentiation of human acute promyelocytic leukemia (APL) cells induced by Tanshinone II A in primary culture]

The aim of this study was to investigate whether Tanshinone II A (Tan II A) can induce human acute promyelocytic leukemia (APL) cells to differentiate or not in primary culture. The APL cells from 5 cases were cultured respectively with Tan II A at the concentration of 0.5 microgram/ml for 7 days in vitro. The differentiations of these leukemia cells were observed cytomorphologically and examined by nitroblue tetrazolium (NBT) test. The cell DNA cycle and membrane cluster differentiation (CD) antigens (CD33, CD11b) were analyzed by flow cytometry. The results showed that 82.5% +/- 4.8% of APL cells were induced into morphologically and functionally differentiated cells. The cell growth curve showed that the growth of APL cells was inhibited. The degree of differentiation and growth inhibition induced by Tan II A was not different from that by ATRA (P > 0.05). Flow cytometry analysis showed that Tan II A arrested APL cells in G0/G1 phase and inhibited cellular DNA synthesis. This study demonstrates that Tan II A can induce differentiation of APL cells in vitro, and hence it is worthy of further studies for clinical use.

Nicotine dependence and its familial aggregation in Chinese

BACKGROUND

Nicotine dependence is a significant public health problem. This study attempted to characterize the prevalence and familial aggregation of nicotine dependence in China.

METHODS

In 1998, we initiated a community-based cross-sectional study among residents of the Yuexi County in Anqing, China. A total of 991 current smokers from 488 randomly selected nuclear families were recruited and surveyed by use of the standardized Fagerstrom Test of Nicotine Dependence (FTND) questionnaire and the Revised Tolerance Questionnaire (RTQ). All study subjects were offspring in their respective nuclear families, and 478 male-male pairs (aged 41.7 +/- 12.1 years) were finally used for data analyses, because the number of female current smokers (n = 5) was too small.

RESULTS

The correlation coefficient of the FTND and the RTQ scores was as high as 0.84 (P < 0.0001). Nicotine dependence, defined as an FTND score > or =8 or an RTQ score > or =28, had a prevalence of 12.7% and 11.1%, respectively. The respective sibling recurrent risk was 1.7 and 2.4, according to the FTND or the RTQ criteria. The adjusted odds ratios and 95% CI of nicotine dependence of second siblings in families in which the first sibling was nicotine dependent were 2.13 (95% CI: 1.02-4.43) and 3.50 (95% CI: 1.65-7.36) respectively, according to the FTND and RTQ criteria.

CONCLUSIONS

The prevalence of nicotine dependence in male current smokers in China was comparable to that reported in previous US and European studies. Our findings suggest that genetic influences may play an important role in vulnerability to nicotine addiction.

Structural basis for substrate specificity of protein-tyrosine phosphatase SHP-1

The substrate specificity of the catalytic domain of SHP-1, an important regulator in the proliferation and development of hematopoietic cells, is critical for understanding the physiological functions of SHP-1. Here we report the crystal structures of the catalytic domain of SHP-1 complexed with two peptide substrates derived from SIRPalpha, a member of the signal-regulatory proteins. We show that the variable beta5-loop-beta6 motif confers SHP-1 substrate specificity at the P-4 and further N-terminal subpockets. We also observe a novel residue shift at P-2, the highly conserved subpocket in protein- tyrosine phosphatases. Our observations provide new insight into the substrate specificity of SHP-1.

Identification of a novel intron and 4 polymorphisms in the gene encoding the gamma subunit of the epithelial sodium channel

The amiloride-sensitive epithelial sodium channel is a highly selective sodium channel that constitutes the rate-limiting step of sodium reabsorption in distal nephrons. It consists of at least 3 subunits (alpha, beta, and gamma) of similar structure and plays an important role in sodium and fluid homeostasis. Defects of this channel have been critically implicated in Liddle syndrome (pseudoaldosteronism) and pseudohypo-aldosteronism type 1. A sample of 48 individuals from 23 nuclear families was selected from Anhui, China. We sequenced 12 exons and flanking intronic sequences and discovered a new 207-bp intron located in the previously described exon X of Thomas et al. (1996). In addition, 4 novel single nucleotide polymorphisms were identified; 3 were in exon 3 and 1 was in exon 13. Furthermore, 2 base substitutions in exon 13 were present in all the Chinese subjects compared with the published European SCNN1G DNA sequence.

Paraoxonase polymorphism and its effect on male reproductive outcomes among Chinese pesticide factory workers

BACKGROUND

Serum paraoxonase has been associated with the metabolism of organophosphate pesticides in humans. Molecular analysis of the human paraoxonase gene (PON1) has revealed that Arg192 homozygotes have a greater detoxifying capability than Gln192 homozygotes. We examined the effects of PON1 genotypes on male reproductive outcomes and its interaction with exposure to organophosphate pesticides.

METHODS

We studied 60 Chinese pesticide-factory workers and 89 textile-factory workers who were unexposed to pesticides. The respective allele frequencies of Arg192 and Gln192 were 0.62 and 0.38. Pesticide exposure among 36 exposed subjects and 12 unexposed subjects, regardless of gender, was assessed by personal measurement of pesticide residues over an entire 8-hr shift and measurement of urinary p-nitrophenol level over a 24-hr period. We analyzed semen and hormone data collected from male subjects.

RESULTS

When the three PON1 genotypes were analyzed separately, a gene dose effect was not detected. We used the unexposed Arg192 homo/heterozygotes as the reference group, and re-analyzed the data. Exposed Arg192 homo/heterozygotes had significantly lower sperm count (chi 2 = 9.01, P < 0.01) and lower percentage of sperm with normal morphology (chi 2 = 4.18, P < 0.05) than the reference group. Both unexposed Gln192 homozygotes (chi 2 = 4.90, P < 0.05) and exposed Arg192 homo/heterozygotes (chi 2 = 10.00, P < 0.01) showed significantly lower sperm concentrations than the reference group. In addition, exposed Arg192 homo/heterozygotes had significantly higher serum LH levels (chi 2 = 7.94, P < 0.01) than the reference group.

CONCLUSIONS

Because of a small sample size, our findings are highly preliminary. Nevertheless, it calls for further investigation of the interaction between the PON1 genotype and organophosphate pesticide exposure on male reproductive outcomes.

Linkage analysis of candidate genes and gene-gene interactions in chinese hypertensive sib pairs

Previous studies of hypertension in humans and experimental animal models have identified a number of candidate genes that have since been implicated as possibly contributing to essential hypertension. Among them are the genes encoding angiotensinogen, renin, the beta- and gamma-subunits of the epithelial sodium channel (beta/gamma-ENaC), alpha-adducin, and kallikrein (KLK). To examine the role of possible contribution of these genes in ethnic Chinese, as well as the epistatic interaction among them, we studied a large cohort of hypertensive sib pairs from China. DNA samples from 310 concordant affected sibling pairs with hypertension were tested for linkage with the use of excess allele-sharing algorithms based on genotyping with highly informative GT-repeat microsatellite markers localized in the immediate vicinity of the genes encoding angiotensinogen, renin, beta- and gamma-ENaC, alpha-adducin, and KLK. Affected sib pair analysis conducted according to 3 different methods (Statistical Analysis for Genetic Epidemiology [S.A.G.E. ]/SIBPAL, MAPMAKER/SIBS, and affected pedigree member [APM] methods) revealed no evidence for linkage of any of these genes to primary hypertension in the population studied. Moreover, 2-locus sib pair linkage analyses to test for gene-gene interactions among each possible pair of candidate genes failed to yield any statistically significant results. Our findings provide no support for a significant contribution of the angiotensinogen, renin, beta/gamma-ENaC, alpha-adducin, or KLK genes, alone or in concert, to the pathogenesis of essential hypertension among Chinese. Our results emphasize the possible role of ethnic differences for complex disease genetics, as well as the need for large, well-characterized investigations.

An extreme-sib-pair genome scan for genes regulating blood pressure

Hypertension, a risk factor for many cardiovascular, cerebrovascular, and renal diseases, affects one in four Americans, at an annual cost of>$30 billion. Although genetic mutations have been identified in rare forms of hypertension, including Liddle syndrome and glucocorticoid-remediable aldosteronism, the abundance of plausible candidate genes and potential environmental risk factors has complicated the genetic dissection of more prevalent essential hypertension. To search systematically for chromosomal regions containing genes that regulate blood pressure, we scanned the entire autosomal genome by using 367 polymorphic markers. Our study population, selected from a blood-pressure screen of >200,000 Chinese adults, comprises rare but highly efficient extreme sib pairs (207 discordant, 258 high concordant, and 99 low concordant) and all but a single parent of these sibs. By virtue of the sampling design, the number of sib pairs, and the availability of genotyped parents, this study represents one of the most powerful of its kind. Although no regions achieved a 5% genomewide significance level, maximum LOD-score values were >2.0 (unadjusted P<.001) for regions containing five markers (D3S2387, D11S2019, D15S657, D16S3396, and D17S1303), in our primary analysis. Other promising regions identified through secondary analyses include loci near D4S3248, D7S2195, D10S1423, D20S470, D20S482, D21S2052, PAH, and AGT.

Blood pressure and the T174M and M235T polymorphisms of the angiotensinogen gene

PURPOSE

The angiotensinogen gene (AGT), which encodes the precursor of the vasoactive hormone angiotensin II, has been reported to be associated with hypertension in Caucasian and Japanese populations. We examined the relationship between two common molecular variants of AGT, T174M and M235T and blood pressure in two cohorts from the Anqing region of China. Cohort I (N = 794) consisted of families ascertained by either hypertensive or hypotensive siblings; and Cohort II (N = 761) represented a collection of randomly selected families.

METHODS

Blood pressure was measured according to standard protocols, and information on age, sex, body mass index, alcohol consumption, and cigarette smoking was collected by trained interviewers using standardized questionnaires. The association of AGT genotypes and blood pressure was examined in multivariate linear regression models, with adjustment for potential intrafamilial correlations. The respective T and M allele frequencies for T174M were 0.93 and 0.07, and 0.80 and 0.20 for M235T among the parents for randomly selected families. All the analyses were conducted after exclusion of individuals currently under antihypertensive medication.

RESULTS

In the pooled analysis of the two cohorts, neither the T174M nor the M235T polymorphism was significantly associated with variations of blood pressure assuming a recessive (T174M: p = 0.73 and 0.61; M235T: p = 0.99 and 0.24; for SBP and DBP), dominant (T174M: p = 0.54 and 0.72; M235T: p = 0.79 and 0.12; for SBP and DBP), or additive (T174M: p = 0.52 and 0.67, M235T: p = 0.91 and 0.11; for SBP and DBP) model. Likewise, no statistically significant association was detected when the two cohorts were analyzed separately. The logistic regression analysis of hypertension also failed to reveal any association with these markers.

CONCLUSIONS

In summary, our analyses suggest that the molecular variants of AGT may not be associated with variations of blood pressure in this rural Chinese population.

[Chiral separation of thio-glycidyl ether on amylose-chiral stationary phase by high performance liquid chromatography]

In the present study, we synthesized amylose-tris(phenylcarbamate), and used it as chiral stationary phase based on silica gel. This stationary phase offered a practically useful chiral separation medium. Amylose was allowed to react with an excess of phenylisocyanate in pyridine for 48 h. The obtained carbamate was dissolved in DMF and adsorbed on silica gel previously treated with 3-aminopropyltriethoxysilane. The mass ratio of the carbamate to the silica gel was 0.45/2.55. The four thio-glycidyl ethers were resolved on the amylose tris(phenylcarbamate) chiral stationary phase. Separation was carried out with a hexane/2-propanol mixture as mobile phase at a flow rate of 1.0 mL/min at room temperature. The effects of 2-propanol concentration on the retention and resolution have been investigated.