Fructose-1,6-bisphosphatase regulates glucose-stimulated insulin secretion of mouse pancreatic beta-cells

Pancreatic β-cells can precisely sense glucose stimulation and accordingly adjust their insulin secretion. Fructose-1,6-bisphosphatase (FBPase) is a gluconeogenic enzyme, but its physiological significance in β-cells is not established. Here we determined its physiological role in regulating glucose sensing and insulin secretion of β-cells. Considerable FBPase mRNA was detected in normal mouse islets and β-cell lines, although their protein levels appeared to be quite low. Down-regulation of FBP1 in MIN6 cells by small interfering RNA could enhance the glucose-stimulated insulin secretion (GSIS), whereas FBP1-overexpressing MIN6 cells exhibited decreased GSIS. Inhibition of FBPase activity in islet β-cells by its specific inhibitor MB05032 led to significant increase of their glucose utilization and cellular ATP to ADP ratios and consequently enhanced GSIS in vitro. Pretreatment of mice with the MB05032 prodrug MB06322 could potentiate GSIS in vivo and improve their glucose tolerance. Therefore, FBPase plays an important role in regulating glucose sensing and insulin secretion of β-cells and serves a promising target for diabetes treatment.

RADIOSENSITIVITY TO HIGH ENERGY IRON IONS IS INFLUENCED BY HETEROZYGOSITY for ATM, RAD9 and BRCA1

Loss of function of DNA repair genes has been implicated in the development of many types of cancer. In the last several years, heterozygosity leading to haploinsufficiency for proteins involved in DNA repair was shown to play a role in genomic instability and carcinogenesis after DNA damage is induced, for example by ionizing radiation. Since the effect of heterozygosity for one gene is relatively small, we hypothesize that predisposition to cancer could be a result of the additive effect of heterozygosity for two or more genes critical to pathways that control DNA damage signaling, repair or apoptosis. We investigated the role of heterozygosity for Atm, Rad9 and Brca1 on cell oncogenic transformation and cell survival induced by 1GeV/n ⁵⁶Fe ions. Our results show that cells heterozygous for both Atm and Rad9 or Atm and Brca1 have high survival rates and are more sensitive to transformation by high energy Iron ions when compared with wild-type controls or cells haploinsufficient for only one of these proteins. Since mutations or polymorphisms for similar genes exist in a small percentage of the human population, we have identified a radiosensitive sub-population. This finding has several implications. First, the existence of a radiosensitive sub-population may distort the shape of the dose-response relationship. Second, it would not be ethical to put exceptionally radiosensitive individuals into a setting where they may potentially be exposed to substantial doses of radiation.

Non-phytate phosphorus requirements and efficacy of a genetically engineered yeast phytase in male Lingnan Yellow broilers from 1 to 21 days of age

This experiment was conducted to investigate the requirement of non-phytate phosphorus (nPP) and efficacy of a genetically engineered yeast phytase in performance and tibia characteristics by male Lingnan Yellow broilers from 1 to 21 days of age. A total of 2640 1-day-old male chicks were randomly allotted to one of 11 dietary treatments, which consisted of six replicate floor pens with 40 birds per pen. All treatments had the same levels of all nutrients except for phosphorus and phytase. The control group (treatment 1) was fed the basal diet without dicalcium phosphate or phytase supplementation. Dietary concentrations of nPP were 0.11%, 0.19%, 0.27%, 0.35%, 0.43%, 0.51% and 0.59% respectively for treatments 1, 2, 3, 4, 5, 6 and 7, through addition of dicalcium phosphate (chemistry grade) to the basal diet. Diets 8-11 were supplemented with a genetically engineered yeast phytase 250, 500, 750 U/kg and a commercial phytase product 500 U/kg in basal diet respectively. The results showed that 0.46% and 0.51% nPP were required for maximum body-weight gain and optimum tibia development indicators respectively. However, 0.59% nPP had a negative effect on bird growth. The equivalency value of the genetically engineered yeast phytase was estimated to be 874 U/kg to liberate 0.1% nPP.

TrkB induces EMT and has a key role in invasion of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) remains a significant public health problem, accounting for over 5% of all cancer-related deaths, and these deaths primarily result from metastatic disease. The molecular processes involved in HNSCC pathogenesis and progression are poorly understood, and here we present experimental evidence for a direct role of the cell surface receptor tyrosine kinase, TrkB, in HNSCC tumor progression. Using immunohistochemical analysis and transcriptional profiling of archival HNSCC tumor specimens, we found that TrkB and its secreted ligand, brain-derived neurotrophic factor (BDNF), are expresses in greater than 50% of human HNSCC tumors, but not in normal upper aerodigestive tract (UADT) epithelia. Studies with HNSCC cell lines reveal that in vitro stimulation with BDNF, the ligand for TrkB, upregulates the migration and invasion of HNSCC cells, and both transient and stable suppressions of TrkB result in significant abrogation of constitutive and ligand-mediated migration and invasion. Furthermore, enforced overexpression of TrkB results in altered expression of molecular mediators of epithelial-to-mesenchymal transition (EMT), including downregulation of E-cadherin and upregulation of Twist. Using an in vivo mouse model of HNSCC, we were able to show that downregulation of TrkB suppresses tumor growth. These results directly implicate TrkB in EMT and the invasive behavior of HNSCC, and correlate with the in vivo overexpression of TrkB in human HNSCC. Taken together, these data suggest that the TrkB receptor may be a critical component in the multi-step tumor progression of HNSCC, and may be an attractive target for much needed new therapies for this disease.

Effect of sodium tanshinone II A sulfonate on the activity of CYP1A2 in healthy volunteers

Sodium tanshinone IIA sulfonate (STS) is a water-soluble derivative of tanshinone IIA, a famous Chinese medicine which has been used in the treatment of cardiovascular disorders for many years. Using caffeine as a probe drug, this project was designed to investigate the effect of STS on the activity of CYP1A2 in humans. Sixteen unrelated healthy volunteers were recruited for this two-phase, randomized and crossover study. The volunteers received either placebo or 60 mg day(-1) of STS injections through vein for 13 days. Pharmacokinetics of caffeine and the metabolite paraxanthine was determined by high-performance liquid chromatography. CYP1A2 activity was monitored by the ratio of paraxanthine to caffeine at 6 h in plasma. Enzyme activity analysis showed that STS significantly increased the activity of CYP1A2 by 41.1% [90% confidence interval (CI), 17.4-64.8%] (p = 0.036). The area under the curve [AUC((0-24h))] of caffeine significantly decreased by 13.3% [90% CI = 7.0-19.6%] (p = 0.005) with 13 days of treatment of STS. AUC((0-24h)) of paraxanthine significantly increased by 17.4% [90% CI = 4.3-30.5%] (p = 0.035). No significant difference was found for other parameters of caffeine and paraxanthine between two phases. STS has significantly induced the activity of CYP1A2 in vivo. Simultaneously, AUC((0-24h)) of caffeine and paraxanthine were significantly affected by STS. The findings have provided some useful information for safe and effective usage of STS in clinic.

The efficacy of topical intralesional BCG-PSN injection in the treatment of erosive oral lichen planus: a randomized controlled trial

BACKGROUND

Nowadays, it has been widely accepted that the local cell-mediated immunologic disorders may play an important role in the pathogenesis of oral lichen planus (OLP). Therefore, we sieved out polysaccharide nucleic acid fraction of bacillus Calmette-Guerin (BCG-PSN) from various immunomodulators to evaluate the short-term therapeutic efficacy and clinical safety of intralesional BCG-PSN injection for erosive OLP.

METHODS

A total of 56 OLP patients were randomly assigned to receive either intralesional injection of 0.5 ml BCG-PSN every other day (31 of 56) or 10 mg triamcinolone acetonide (TA, a positive-controlled group, 25 of 56) every week for 2 weeks. After the cessation of treatment, those cured from erosion were followed up for 3 months. Another two researchers measured erosive areas and recorded visual analog scale (VAS) scores both at the start and the end of the treatment. We also registered adverse reactions and the recurrence intervals.

RESULTS

After 2-week treatment, 27 of 31 BCG-PSN-treated patients (87.1%) and 22 of 25 TA-treated patients (88.0%) healed. There were no statistical differences between the two groups in erosive areas (27.86 +/- 27.97 vs. 25.68 +/- 34.65, P = 0.801) and VAS scores (2.45 +/- 1.64 vs. 2.40 +/- 1.38, P = 0.946). Three of 31 BCG-PSN-treated patients (9.7%) vs. 2 of 25 TA-treated patients (8.0%) experienced the swelling or burning sensation (P = 0.827). A total of 49 of 56 patients were followed up. There were no statistical differences in the recurrence rates (33.3% vs. 45.5%, P = 0.386) and intervals (80.89 +/- 26.83 vs. 73.48 +/- 28.11, P = 0.419).

CONCLUSIONS

Topical intralesional BCG-PSN injection is as effective as TA for erosive OLP, which suggests that topical intralesional BCG-PSN injection can be a promising therapeutic alternative for erosive OLP, especially for those insensitive, or even resistant, to glucocorticoids.

AMPK activators--potential therapeutics for metabolic and other diseases

AMP-activated protein kinase (AMPK)-mediated cellular metabolic responses to tissue-specific and whole-body stimuli play a vital role in the control of energy homeostasis. As a cellular energy-sensing mechanism, AMPK activation stimulates glucose uptake and fat oxidation, while it suppresses lipogenesis and gluconeogenesis. The cumulative effects of AMPK activation lead to beneficial metabolic states in liver, muscle and other peripheral tissues that are critical in the pathogenesis of obesity, type 2 diabetes and related metabolic disorders. Activators of AMPK that target selected tissues hold potential as novel therapeutics for diseases in which altered energy metabolism contributes to aetiology.

Development of a simple and effective method for specific detection of Pepper mild mottle virus

A digoxigenin (DIG)-labeled cDNA probe complementary to the region from 5,256-6,300 nt of Pepper mild mottle virus (PMMoV) genome was synthesized. The specificity and sensitivity of the probe was tested by the dot-blot hybridization. The detection limit of this method was equivalent to 0.8 microg of fresh infected tissue in each spot. Double-antibody sandwich (DAS) ELISA and RT-PCR had the detection limit 39 microg and 0.008 microg of fresh infected tissue, respectively. We evaluated leaf, fruit pulp, and seed of pepper plant by dot-blot hybridization and found all the tested tissues suitable for detection of PMMoV. Finally, 111 tissue samples including 93 samples collected from the pepper fields of Beijing and Baoding and 18 commercial seed samples were evaluated by this method. The results showed that the incidence rate of the infected samples was 14% and 61% for the field samples and commercial seeds, respectively. The high sensitivity and reliability of the molecular hybridization assay provided an important alternative method for the detection of PMMoV in a large-scale.

Clinical analysis of nervous system involvement in ANCA-associated systemic vasculitides

OBJECTIVE

To assess the clinical features of nervous system (NS) involvement in patients with ANCA-associated vasculitides (AAV), including microscopic polyangiitis (MPA), Wegener's granulomatosis (WG), and Churg-Strauss syndrome (CSS).

METHODS

One hundred and seventy-nine patients admitted to Peking Union Medical College Hospital from 1995 to 2008, including 93 cases of MPA, 61 cases of WG, and 25 cases of CSS, were enrolled in this study. Medical charts including demographic data, clinical features, laboratory findings, treatments and outcomes were systematically reviewed.

RESULTS

NS involvements were observed in 36.6% of MPA, 50.8% of WG, and 76.0% of CSS patients. Peripheral neuropathy predominated in each type of AAV. In CSS and MPA, the majority was mononeuritis multiplex and distal symmetrical polyneuropathy, whereas, differently, 64.5% of WG patients with NS involvement had cranial neuropathy. Central nervous system (CNS) involvement accounted for 21.1%, 29.4%, and 32.3% of neuropathy respectively in CSS, MPA and WG patients, including arachnoid hemorrhage, cerebrovascular neuro-pathy, meningitis, and diffuse brain damage. 157 (87.7%) AAV patients responded to treatment with high dose of prednisone plus immunosuppressants. Thirteen (14.0%) MPA and four (6.6%) WG patients died. The leading causes of death were diffuse alveolar hemorrhage (DAH) (6, 35.3%) and infection (6, 35.3%). No patient died directly of neuropathy.

CONCLUSION

NS involvement was common in AAVs and the characteristic of NS involvement was different among MPA, WG and CSS patients. DAH and infection instead of NS damage remained the leading causes of death in AAVs.

Quantum dots-based multiplexed immunohistochemistry of protein expression in human prostate cancer cells

Semiconductor quantum dots (QDs) are bright fluorescent nanoparticles that have been successfully used for the detection of biomarker expression in cells. The objective of the present study is to use this technology in a multiplexing manner to determine at a single cell level the expression of a cell-specific bio-marker, prostate-specific antigen (PSA) expressed by human prostate cancer LNCaP and ARCaP cell lines. Here we compared the sensitivity of immunohistochemistry (IHC) and QD-based detection of AR and PSA expression in these cell lines. Further, we conducted multiplexing QD-based detection of PSA and androgen receptor (AR) expression in LNCaP cells subjecting to androgen (R1881) stimulation. The involvement of AR in PSA regulation in LNCaP cells, at a single cell level, was confirmed by the co-incubation of LNCaP cells in the presence of both R1881 and its receptor antagonist, bicalutamide (Casodex). We showed here the superior quality of QDs, in comparison to IHC, for the detection of AR and PSA in cultured LNCaP and ARCaP cells. Multiplexing QDs technique can be used to detect simultaneously AR and PSA expression induced by R1881 which promoted AR translocation from its cytosolic to the nuclear compartment. We observed AR antagonist, bicalutamide, inhibited AR nuclear translocation and PSA, but not AR expression in LNCaP cells.

Regulation of alveolar epithelial function by hypoxia

Patients with acute respiratory distress syndrome and high-altitude pulmonary oedema build up excess lung fluid, which leads to alveolar hypoxia. In patients with acute respiratory distress syndrome and hypoxia, there is a decrease in oedema fluid clearance, due in part to the downregulation of plasma membrane sodium-potassium adenosine triphosphatase (Na,K-ATPase). In alveolar epithelial cells, acute hypoxia promotes Na,K-ATPase endocytosis from the plasma membrane to intracellular compartments, resulting in inhibition of Na,K-ATPase activity. Exposure to prolonged hypoxia leads to degradation of plasma membrane Na,K-ATPase. The downregulation of plasma membrane Na,K-ATPase reduces adenosine triphosphate demand, as part of a survival mechanism of cellular adaptation to hypoxia. Hypoxia has also been shown to disassemble and degrade the keratin intermediate filament network, a fundamental component of the cell cytoskeleton, affecting epithelial barrier function. Accordingly, better understanding of the mechanisms regulating cellular adaptation to hypoxia may lead to the development of novel therapeutic strategies for acute respiratory distress syndrome and high-altitude pulmonary oedema patients.

Gene expression profiling of breast cells induced by X-rays and heavy ions

Several genetic aberrations and gene expression changes have been shown to occur when cells are exposed to various types of radiation. The integrity of DNA depends upon several processes that include DNA damage recognition and repair, replication, transcription and cell cycle regulation. Ionizing radiation has many sources, including radon decay from the soil and X-rays from medical practice. Epidemiological evidence indicates a risk for cancer by inducing genetic alterations through DNA damage, and molecular alterations have been reported in epidemiological studies of the A-bomb survivors. A spontaneously immortalized human breast epithelial cell model, MCF-10F, was used to examine the gene expression profiling of breast cells induced by X-ray and heavy ion exposure, by a cDNA expression array of DNA damage and repair genes. This cell line was exposed to 10, 50, 100 and 200 cGy of either X-rays or heavy ions and gene expression profiles were studied. Results indicated that out of a total of 161 genes, 38 were differentially expressed by X-ray treatment and 24 by heavy ion (Fe(+2)) treatment. Eight genes were common to both treatments and were confirmed by Northern blot analysis: BRCA1, BIRC2/CIAP1, CENP-E, DDB1, MRE11A, RAD54/ATRX, Wip1 and XPF/ERCC4. A number of candidate genes reported here may be useful molecular biomarkers of radiation exposure in breast cells.

Possible role of hydrogen sulfide on the preservation of donor rat hearts

OBJECTIVE

The aim of this study was to observe the preservative effect of hydrogen sulfide (H2S) on donor rat hearts.

MATERIALS AND METHODS

The hearts of 24 Sprague-Dawley rats were perfused on a Langendorff perfusion column for 30 minutes. We calculated and recorded the left ventricular-developed pressure (LVDP), and positive and negative derivatives of left ventricular systolic pressure (LVSP; +dP/dt and -dP/dt). Hearts were then arrested and stored for 6 hours at 4 degrees C: group 1, Krebs-Henseleit (KH) solution; group 2, KH solution with 1 micromol/L NaHS; group 3, KH solution with 1 micromol/L NaHS and 10 micromol/L glibenclamide; group 4, St. Thomas II solution. Hearts were transferred back to the Langendorff column. After stabilizing for 30 minutes, LV performance was assessed as before. The donor hearts were kept for pathological study including myocardial water ratio, ATP content, and myocyte apoptosis index.

RESULTS

The recovery rates of +dp/dtmax, -dp/dtmax, and LVDP of groups 2 and 4 were much better than those of groups 1 and 3. The hearts contracted immediately after reperfusion in group 4. Ventricular fibrillation was seen before contraction in the other 3 groups, with the longest duration in group. No significant difference in myocardial water ratio was found. The ATP content was the highest in group 2. Apoptosis was observed in the 4 groups with the lowest apoptosis index in group 2.

CONCLUSIONS

H2S has a protective effect on rat donor hearts at the concentration of 1 micromol/L. The protective effect is better than that of St. Thomas II solution. The protective effect of H2S can be blocked by glibenclamide.

Cerebral White Matter Lesions and Cognitive Function in a Non-demented Chinese Veteran Cohort

This study examined the association between cerebral white matter lesions (WMLs) and cognitive function in a male, non-demented Chinese veteran cohort. A total of 662 participants underwent CT scan and cognitive function assessments; 51 were excluded from the analysis because they exhibited non-lacunar infarcts or suspected dementia. Subjects were allocated to one of four groups according to WML status and between-group comparisons were made for seven cognitive function tests. Logistic regression was used to assess odds ratios for impaired performance associated with WML status. In all cognitive tests, subjects with severe WMLs differed significantly from those without WMLs or with mild WMLs, and in three tests subjects with severe WMLs differed significantly from those with moderate WMLs. For each cognitive test severe WMLs were strongly associated with increased risk of impaired performance. Severe WMLs were associated with greater diminished cognitive function and there may be a WML threshold after which, in elderly Chinese subjects, an impact on cognitive function occurs.

Association of CYP3A4*18B polymorphisms with the pharmacokinetics of cyclosporine in healthy subjects

The aim of this study is to evaluate the association of the CYP3A4*18B genotype with the cyclosporine metabolism in healthy subjects. We employed PCR-RFLP assays for analysis of the CYP3A4*18B genotype. Each of 26 subjects, comprising 12 CYP3A4*1/*1, 12 CYP3A4*1/*18B and 2 CYP3A4*18B/*18B, was given a single oral dose of cyclosporine (4 mgkg(-1)). The plasma concentrations of cyclosporine were measured for up to 24 h post dose by high-performance liquid chromatography-electrospray mass spectrometry. We found that the mean Cmax (95% confidence intervals) of cyclosporine were 2237 (2905, 1859) (*1/*1), 2247 (2916, 1869) (*1/*18B), and 905 (1192, 506) ng ml(-1) (*18B/*18B)(p = 0.037) and the mean AUCO-4 were 5026 (6181, 4372) (*1/*1), 4434 (5481, 3841) (*1/*18B) and 2561 (3155, 1736) ng ml(-1) h (*18B/*18B) (p=0.021). The CL in the *18B/*18B group was significantly higher than in the *1/*1 group. However, Tmax exhibited no difference among the three genotypes. *18B/*18B group showed 50% reduction in concentration at 2 h post dose compared with *1/*18B (p = 0.062) or *1/*1 (p = 0.047), but no statistical significance was detected between*1/*1 and *1/*18B groups (p > 0.05). The data suggest that the CYP3A4*18B genotype affects cyclosporine pharmacokinetics probably resulting from a higher enzymatic activity of this mutation in healthy subjects.

Genetically identical twin transplantation for chronic lymphocytic leukemia

We identified 19 persons with B-cell chronic lymphocytic leukemia (CLL) who received genetically identical twin blood cell or bone marrow transplants after high-dose conditioning. Ten are alive (eight disease-free) with a median follow-up of 89 months (range, 31-171 months); 5-year relapse rate was 50% (95% confidence interval (CI), 26-73%). Estimated 5-year survival and disease-free survival were 61% (95% CI, 37-82%) and 45% (95% CI, 23-68%). In two of four patients tested at 12 and 21 months by polymerase chain reaction no evidence of residual CLL was detected post-transplant. In one recipient who relapsed at 6 years, molecular studies showed a different CLL clone from that detected pretransplant. This clone was subsequently identified in the donor suggesting transfer of occult leukemia at the time of transplant. Genetically identical twin transplants can result in long-term disease-free survival and molecular remissions, these data suggest the potential for CLL control in the absence of allogeneic graft-versus-leukemia effect. The case of leukemia transfer indicates the need for careful evaluation of donors prior to graft collection.

Nested-PCR Detection and Sequence Confirmation of 'Candidatus Liberibacter asiaticus' from Murraya paniculata in Guangdong, China

Murraya paniculata (orange jasmine) is a popular ornamental rutaceaous plant and is known to be a preferred host for the Asian citrus psyllid, Diaphorina citri (Kuwayana), the primary vector of 'Candidatus Liberibacter spp.' that causes citrus Huanglongbing (HLB). HLB is a highly destructive citrus disease worldwide. However, the presence of 'Ca. Liberibacter spp.' in M. paniculata remains uncertain (2). Clarification of M. paniculata as a host of 'Ca. Liberibacter spp.' has direct impact on HLB control programs. During June of 2006, we identified three M. paniculata trees near a mandarin orchard affected by HLB in Luoding City and two trees from Guangzhou City, Guangdong Province, People's Republic of China. All trees had leaves showing yellowing and mottling symptoms characteristic of HLB. Both symptomatic and asymptomatic leaves were collected. DNA was extracted using the CTAB (cetyltrimethylammoniumbromide) method and assayed by nested-PCR. The general bacterial 16S rDNA primer set fDl/rD1 (3) was used for the first round of amplification. Amplification was conducted as previously described (1), and 2 μl of PCR reaction product were used for a second round of amplification using the same procedure but with 35 PCR cycles with primer set OI1/OI2c (3,4). After agarose gel electrophoresis and staining with ethidium bromide, a 1.1-kb DNA band was unambiguously associated with symptomatic but not asymptomatic leaf samples. Nonnested-PCR using primer set OI1/OI2c alone did not yield a target DNA band or yielded a very weak DNA band. XbaI digestion of the nested-PCR DNA product yielded two fragments, 520 and 640 bp long, characteristic of 'Ca. L. asiaticus'. PCR amplicons were sequenced and were 1,095 bp long. This sequence shared >98% similarity to sequences of 'Ca. L. asiaticus' in the GenBank database. We observed that nested-PCR is necessary for consistent amplification of DNA from 'Ca. L. asiaticus' from M. paniculata. We excluded the possible nonspecific amplification associated with nested-PCR by XbaI restriction enzyme digestion and by nucleotide sequence analysis. Our data indicate that M. paniculata is a host of 'Ca. L. asiaticus' but the bacterial titer might be low. References: (1) X. Deng et al. Online publication. doi:10.1094/PHP-2007-0419-01-BR. Plant Health Progress, 2007. (2) M. Garnier and J. Bove. Huanglongbing (Greening). Page 46 in: Compendium of Citrus Diseases. 2nd ed. L. W. Timmer et al., eds. The American Phytopathological Society, St. Paul, MN, 2000. (3) S. Jagoueix et al. Int. J. Syst. Bacteriol. 44:379, 1994. (4) S. Jagoueix et al. Mol. Cell. Probes 10:43, 1996.

Tissue Engineering and Tissue Repair in Immunocompetent Animals: Tissue Construction and Repair

Tissue engineering can regenerate autologous tissue using a biodegradable scaffold and in vitro expanded cells derived from small biopsy samples, and thus may have great potential for tissue repair and reconstruction in plastic and reconstructive surgery. As an important step towards a clinical application, research work in large animals is essential. This article presents our experience of tissue engineering and repair in large animals in the areas of bone, cartilage and tendon.

Transcriptional silencing of the TMS1/ASC tumour suppressor gene by an epigenetic mechanism in hepatocellular carcinoma cells

DNA methylation and histone modifications have emerged as key mechanisms in transcriptional regulation. The target of methylation-induced silencing 1 (TMS1) is a bipartite protein. Recent studies have indicated that methylation-associated silencing of TMS1 occurs in many cancers. However, whether and how TMS1 is regulated by epigenetic mechanisms in cancers remains unknown. In this study we showed that methylation of the TMS1 promoter occurred in five of six hepatocellular carcinoma (HCC) cell lines. TMS1 expression was reduced in four HCC cell lines and correlated with methylation status. Furthermore, the TMS1 promoter was completely methylated and mRNA expression was undetectable. TMS1 expression could be restored by 5-aza-2'-deoxycitidine (5-Aza-dC) (a DNA methyltransferase inhibitor) or trichostatin A (TSA) (a histone deacetylase inhibitor) alone and the promoter methylation was partially reversible. TSA was more efficient than 5-Aza-dC in inducing TMS1 expression, and the combination of 5-Aza-dC and TSA resulted in markedly synergistic reactivation of the gene and completely reversed promoter methylation. Interestingly, TMS1 promoter methylation-associated gene silencing was accompanied by histone H3 Lysine 9 (H3K9) hypoacetylation and trimethylation. 5-Aza-dC and/or TSA also had some effect on conversion of methylated to acetylated H3K9 in restoring TMS1. This conversion was dynamic at the TMS1 promoter and a decrease in H3K9 trimethylation preceded an increase in H3K9 acetylation after 5-Aza-dC and/or TSA treatment. Our results thus suggest that epigenetic inactivation of TMS1 expression is regulated by promoter hypermethylation and H3K9 modifications in a coordinated way.

A Chinese isolate of barley yellow dwarf virus-PAV represents a third distinct species within the PAV serotype

The complete nucleotide sequence of barley yellow dwarf virus (BYDV) PAV-CN genomic RNA was determined. This represents the seventh complete genome sequence of a BYDV-PAV serotype. The genome organization of PAV-CN was comparable to that of other BYDV-PAV serotypes, but the nucleotide sequence of full genome was only 76.9-80.3% similar. Sequence similarity of individual open reading frames and untranslated regions (UTR) between PAV-CN and other PAV isolates ranged from 37.9 to 98.2%. Overall, PAV-CN was most similar to BYDV-PAS, which belongs to one of two distinct species within the PAV serotype of BYDV, although the 5' UTR and ORF1 of PAV-CN was most similar to BYDV-GAV, another member of the genus Luteovirus that is not serologically related to BYDV-PAV. These data suggest that PAV-CN may have undergone a recombination event with GAV and that PAV-CN represents a third distinct species within the PAV serotype of BYDV.

Expression of the barley yellow dwarf virus-GAV movement protein and its detection in the infected and transgenic plants

Movement proteins (MPs) that facilitate virus movement in the plants were identified in a number of plant viruses. In this study, full-length MP gene of the Chinese isolate Barley yellow dwarf virus-GAV (BYDV-GAV) was cloned and expressed in Escherichia coli. About 32% of the expressed MP was soluble providing the concentration of isopropyl-beta-D-galactopyranoside (IPTG), time of the induction, temperature and shaking speed were optimized. The soluble MP was purified using nickel-affinity column. Immune serum prepared against purified MP was used for the detection of MP in the BYDV-GAV infected leaves of oat and in the leaves of transgenic wheat plants expressing the full-length and truncated MP gene.

First Report of the Occurrence of Wheat dwarf virus in Wheat in China

In May of 2004 and 2005, several diseased wheat (Triticum aestivum L.) plants showing extreme dwarfing, various types of yellowing, and reduced or no heading were found in the breeding fields of the Institute of Crop Science, Shanxi Academy of Agricultural Sciences, Taiyuan, Shanxi Province, China. On the basis of these symptoms, infection with Wheat dwarf virus (WDV) was suspected. Total DNA was extracted from diseased plants with the DNeasy Plant Mini kit (Qiagen, Hilden, Germany). Primers were designed based on the WDV-Enkoping1 genome sequence (NC_003326) (1), including: 245f, 5'-CGACTACGCCTGGCGAACATTTG-3' (residues 245-267); 806r, 5'-TCTGGCATTGCCTGTTTCGG-3' (complementary to residues 787-806); 1381f, 5'-CAGTGACATCTTCGCCGGAG-3' (residues 1381-1400); and, 1886r, 5'-ACTCCGTAAGCCTCGAATCC-3' (complementary to residues 1867-1886). With primer pairs 245f/806r, 1381f/1886r, 245f/1886r, and 1381f/806r, PCR products of 560, 506, 1642, and 2,275 bp were expected, respectively. After amplification, fragments of the expected sizes were seen on 1% (w/v) agarose gels. The fragments were purified by using a DNA gel extraction kit (TaKaRa, Dalian, China) and cloned into the pGEM-T vector (Promega, Madison, WI). The plasmids were transformed into E. coli strain DH5α and plasmid DNA was isolated from overnight cultures by alkaline lysis. Insert sequences were determined using the dideoxynucleotide chain termination method with an automated sequencer (ABI BigDye 3.1, Applied Biosystems, Foster City, CA). At least three independently isolated clones were analyzed for each PCR product. The compiled 2,750 nt sequence (GenBank Accession No. DQ868525) was 98.1, 98.5, 97.8, and 97.9% identical to WDV-Enkoping1 (NC_003326), WDV-SE (X02869), WDV-B (AM040732), and WDV-F (AM040733), respectively. Therefore, the virus isolate (WDV-TY) was identified as WDV (genus Mastrevirus, family Geminividae). Wheat samples collected from different provinces from 2004-2006 were also infected with WDV as indicated by PCR using the same primer pairs. For Shijiazhuang (Hebei Province), Yangling (Shanaxi Province), Kunming (Yunnan Province), Yuncheng (Shanxi Province), Tianshui (Gansu Province), Gangu (Gansu Province), and Zhenzhou (Henan Province), 13 of 14, 6 of 6, 5 of 5, 4 of 4, 2 of 3, 1 of 2, and 1 of 1 samples were positive, respectively, indicating a broad distribution of WDV in China. To our knowledge, this is the first report of WDV in wheat in China. Reference: (1) A. Kvarnheden et al. Arch Virol. 147:205, 2002.

The frequency of symptoms in transient ischaemic attack: analysis of Nanjing Stroke Register Program data

The clinical characteristics of 172 patients experiencing single or multiple (two or more) transient ischaemic attacks (TIAs) were investigated. Risk factors, clinical manifestations and vascular examinations were compared. Intracranial and extra-cranial large-artery disease (stenosis > or = 50%) occurred more frequently in multiple-TIA patients than in single-TIA patients, and weakness and atrial fibrillation were observed more frequently in single TIA than in multiple TIA patients. The type of aetiological examination performed in TIA patients should depend on the frequency of attacks.

Characterization of moisture-sensitive raw materials with simple spectroscopic techniques

The quality of raw materials used in a synthetic process needs to be properly controlled in order to ensure optimal reaction conversion and desired quality of the resulting product. For air and water sensitive raw materials, quantitative analysis can be a challenging task. Spectroscopic techniques possess advantages of simple operation, fast analysis, low consumable costs and high sample throughput for the analysis of reactive raw materials. Three case studies utilizing spectroscopic analysis for air and water sensitive materials are discussed. First, FT-IR spectroscopy was utilized to determine the amount of residual acetic acid in acetic anhydride key raw material. Acetic anhydride was used in a methylenation reaction where the presence of residual acetic acid could quench a base used in the reaction, leading to incomplete conversion. A simple, one-frequency calibration method was developed to quantify acetic acid in acetic anhydride (2-35wt.%). Next, a novel near infrared reflectance spectroscopy (NIRS) method was used to determine the concentration of diisobutyl aluminum hydride (DIBAL-H) in toluene. DIBAL-H is a highly reactive and moisture-sensitive reagent used as a key raw material for the reduction of an active intermediate. A calibration method based on one-frequency was also developed to determine the concentration of DIBAL-H in toluene (0-1.5mole/L). Finally, a NIRS method based on partial least squares regression (PLS) was developed to quantify p-toluenesulfonic acid in p-toluenesulfonic anhydride, which is not amenable to chromatographic analysis.

Short-term administration of ACTH improves plasma lipid profile and renal function in kidney transplant patients

The present study investigated effects of short-term administration of adrenocorticotrophic hormone (ACTH) on blood lipid profile and renal function in kidney transplant patients. Six patients who had kidney transplantations 2 to 10 years earlier received ACTH intramuscularly (1 mg/d) for 4 days. We analyzed serum levels of lipids, lipoproteins, apolipoproteins, blood creatinine, and other parameters. Short-term ACTH treatment significantly decreased serum apolipoprotein B and apolipoprotein AI, whereas it significantly increased plasma high-density lipoproteins (HDL). Interestingly, creatinine level moderately decreased and creatinine clearances moderately increased among five of six patients. Hepatic function and serum concentration of cyclosporine did not change. There were no serious side effects during ACTH treatment. It was concluded that ACTH treatment had beneficial effects on serum lipoprotein profile, potentially improving renal function in kidney transplant patients. Further observations are needed to confirm these effects.

Proteasomes from Structure to Function: Perspectives from Archaea

Insight into the world of proteolysis has expanded considerably over the past decade. Energy-dependent proteases, such as the proteasome, are no longer viewed as nonspecific degradative enzymes associated solely with protein catabolism but are intimately involved in controlling biological processes that span life to death. The proteasome maintains this exquisite control by catalyzing the precisely timed and rapid turnover of key regulatory proteins. Proteasomes also interplay with chaperones to ensure protein quality and to readjust the composition of the proteome following stress. Archaea encode proteasomes that are highly related to those of eukaryotes in basic structure and function. Investigations of archaeal proteasomes coupled with those of eukaryotes has greatly facilitated our understanding of the molecular mechanisms that govern regulated protein degradation by this elaborate nanocompartmentalized machine.

Molecular variability of the coat protein gene of Potato virus Y from tobacco in China

Thirty-three tobacco samples showing typical symptoms of Potato virus Y (PVY) infection were obtained from tobacco fields in various regions of China. The results of indirect ELISA confirmed the infection with PVY. All the isolates had a capacity to infect tobacco systemically in greenhouse, causing either of two main symptoms: veinal necrosis and mosaic. The nucleotide and amino acid sequences of the coat protein (CP) gene and protein, respectively, of the isolates were determined. Comparison of the isolates revealed a high conservation of the CP gene with an identity of 83.2%. A phylogenetic tree of 41 Chinese isolates of PVY, based on complete CP gene, showed 3 groups corresponding to the strains PVYNTN (A group), PVYO (C group) and a putative new strain similar to PVYN (B group). The amino acid sequences of complete CP protein of the isolates showed an identity of 87.6%. The highest identity was observed in the C-terminal half of the CP protein, where only 11 amino acid differences could be observed, in contrast to the N-terminal half with 22 differences.

Herpes simplex virus 1 recombinant virions exhibiting the amino terminal fragment of urokinase-type plasminogen activator can enter cells via the cognate receptor

Earlier this laboratory constructed a herpes simplex virus 1 recombinant (R5111) that carries a IL13 ligand inserted into glycoprotein D and can enter cells via the IL13Ralpha2 receptor commonly expressed on the surface of malignant glioma cells. In this report, we describe the properties of two recombinant viruses carrying chiemric gD genes. In R5181 recombinant virus the chimeric gene consisted on the residues 20-155 of urokinase plaminogen activator (uPA) inserted between residues 24 and 25 of gD. In R5182 the insert consisted of a 23-residue sequence encoding the uPA binding domain for the urokinase plaminogen activator receptor (uPAR). These viruses were constructed for three reasons, to increase the number of viruses that specifically target receptors on the surface of malignant glioma cells, to determine whether viruses exhibiting novel ligands could enter cells via receptors anchored to the cell surface via glycosylphosphatidylinositol anchor as has been recently demonstrated for nectin1, and to determine whether receptors other than IL13Ralpha2 could be targeted by genetic engineering of the virus. We report that R5181 but not R5182 recombinant virus was able to enter cells expressing uPAR. The results indicate that HSV-1 recombinant viruses can be engineered to enter cells via a variety of unrelated nonviral receptors, including receptors that are anchored to the cells surface but without transmembrane domains.

A cross-sectional study of smoking risk factors in junior high school students in Henan, China

This study was conducted to determine the predictors of tobacco use among junior high school students in Henan. Two thousand seven hundred sixty-three students (from grades 7 to 9) were studied. Demographic, smoking-related, and other predictor variables was investigated. Overall, 6.6% of students were current smokers; 8.7% students reported having tried cigarettes before; and 42.1% of current smokers and 34.2% of triers experimented with smoking during ages 10-12. Of the factors associated with student tobacco use, mother and peer smoking were the strongest independent predictors. The school's negative attitude towards smoking was an important protective factor for preventing student smoking behavior. These findings revealed that effective smoking prevention interventions needed to be comprehensive.

Single nucleotide polymorphisms and haplotypes of histamine N-methyltransferase in patients with gastric ulcer

INTRODUCTION

Histamine plays a crucial role in the regulation of gastric acid secretion, which is involved in the pathogenesis of peptic ulcer. Histamine N-methyltransferase (HNMT) is the major metabolizing enzyme for histamine inactivation in human stomach.

OBJECTIVE

This study aims to determine whether there exists a relationship between HNMT gene polymorphisms and the risk for gastric ulcer (GU).

METHODS

118 GU patients and 154 ethnically matched control subjects were enrolled and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assays were developed to genotype all these subjects for the T-1637C, C-411T, C314T and A1097T point mutations in HNMT gene. Haplotypes were reconstructed from the genotype data.

RESULTS

Frequencies of the variant alleles in cases and controls were 0.398 vs 0.396 for T-1637C, 0.144 vs 0.110 for C-411T, 0.034 vs 0.042 for C314T, and 0.242 vs 0.273 for A1097T, respectively, with no significant difference for any locus between the two groups (all P > 0.05). Also the frequencies of genotypes, haplotypes and haplotype pairs based on these polymorphisms did not differ significantly between cases and controls.

CONCLUSION

This study provided no evidence for the involvement of HNMT polymorphisms in the susceptibility to GU.

Linkage Disequilibrium and Haplotype Architecture for two ABC Transporter Genes (ABCC1 and ABCG2) in Chinese Population: Implications for Pharmacogenomic Association Studies

Information about linkage disequilibrium (LD) patterns and haplotype structures for candidate genes is instructive for the design and analysis of genetic association studies for complex diseases and drug response. ABCC1 and ABCG2 are genes coding for two multidrug resistance (MDR) associated transporters; they are also related to some pathophysiological traits. To pinpoint the LD profiles of these MDR genes in Chinese, we systemically screened 27 unrelated individuals for single nucleotide polymorphisms (SNPs) in the coding and regulatory regions of these genes, and thereby characterized their haplotype structures. Despite marked variations in haplotype diversity, LD pattern and intragenic recombination intensity between the two genes, both loci could be partitioned into several LD blocks, in which a modest number of haplotypes accounted for a high fraction of the sampled chromosomes. We concluded that each locus has its own genomic LD profile, but that they still share a common segmental LD architecture with low haplotype diversity. Our data will benefit genetic association studies of complex traits and drug response possibly related to these genes.

Identification of systemically expanded activated T cell clones in MRL/lpr and NZB/W F1 lupus model mice

CD4(+) T lymphocytes play an important role in the pathogenesis of systemic lupus erythematosus (SLE). To characterize the clonal expansion of CD4(+) T cells in murine lupus models, we analysed the T cell clonality in various organs of young and nephritic MRL/lpr and NZB/W F1 mice using reverse transcription-polymerase chain reaction (RT-PCR) and subsequent single-strand conformation polymorphism (SSCP) analysis. We demonstrated that some identical T cell clonotypes expanded and accumulated in different organs (the bilateral kidneys, brain, lung and intestine) in nephritic diseased mice, and that a number of these identical clonotypes were CD4(+) T cells. In contrast, young mice exhibited little accumulation of common clones in different organs. The T cell receptor (TCR) V beta usage of these identical clonotypes was limited to V beta 2, 6, 8.1, 10, 16 and 18 in MRL/lpr mice and to V beta 6 and 7 in NZB/W F1 mice. Furthermore, some conserved amino acid motifs such as I, D or E and G were observed in CDR3 loops of TCR beta chains from these identical CD4(+) clonotypes. The existence of systemically expanding CD4(+) T cell clones in the central nervous system (CNS) suggests the involvement of the systemic autoimmunity in CNS lesions of lupus. FACS-sorted CD4(+)CD69(+) cells from the kidney displayed expanded clonotypes identical to those obtained from the whole kidney and other organs from the same individual. These findings suggest that activated and clonally expanded CD4(+) T cells accumulate in different tissues of nephritic lupus mice, and these clonotypes might recognize restricted T cell epitopes on autoantigens involved in specific immune responses of SLE, thus playing a pathogenic role in these lupus mice.

Complete nucleotide sequence of a potyvirus causing maize dwarf mosaic disease in central China

The full-length nucleotide sequence of a potyvirus causing the maize dwarf mosaic (MDM) disease in Henan province, central China, was obtained by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of the cDNA 5'-end (5'-RACE). The viral genome comprised of 9596 nucleotides except the polyA tail and encoded a putative polyprotein of 3603 amino acids. The entire genomic sequence of this isolate shared identities of 94.2% and 98.3% with Sugarcane mosaic virus (SCMV) HZ isolate at the nucleotide and deduced amino acid levels, respectively, but only a 69.1% identity with MDM virus (MDMV) Bulgarian isolate (MDMV-Bg) at the nucleotide level. Phylogenetical tree analysis of the complete nucleotide sequences indicated that the Henan isolate of a potyvirus causing MDM disease is in fact a Henan strain of SCMV (SCMV-HN).

Nucleotide sequences of the coat protein and readthrough protein genes of the Chinese GAV isolate of barley yellow dwarf virus

The nucleotide sequences of the coat protein (CP) and readthrough protein (RTP) genes of the Chinese GAV isolate of Barley yellow dwarf virus (BYDV) were determined. The CP and RTP genes of GAV isolate comprised 600 and 1374 nucleotides, respectively. When the CP and RTP gene sequences of GAV isolate were compared with those of BYDV isolates MAV-PS1, P-PAV, NY-SGV and Cereal yellow dwarf virus RPV (CYDV-RPV), the highest similarity (97.2%) between the CP genes of GAV and MAV-PS1 isolates was observed, while the RTP genes of these two isolates shared a lower similarity (87.8%). The results of the alignment of the deduced amino acid sequences of RTP showed that the sequence diversity observed was located at the C terminus.