Comparisons of different metabolic syndrome definitions and associations with coronary heart disease, stroke, and peripheral arterial disease in a rural Chinese population

OBJECTIVES

We estimated the prevalence of metabolic syndrome (MetS) and compared associations of different MetS definitions with coronary heart disease (CHD), stroke, and peripheral arterial disease (PAD) in a rural Chinese population.

METHODS

Among 4,748 residents (2,145 men and 2,603 women) aged 30+ years in rural China from 2006 to 2007, the prevalence of MetS was estimated by using five different definitions: modified World Health Organization (WHO), Chinese Diabetes Society (CDS), the updated National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) for Asian-Americans, International Diabetes Federation (IDF), and Joint Interim Statement (JIS). Multivariable logistic regression analyses were implemented to estimate the association between MetS and the prevalence of CHD, stroke and PAD, respectively.

RESULTS

Prevalence of MetS in men was 11.5% (WHO), 14.8% (CDS), 32.4% (NCEP-ATP III), 27.5% (IDF) and 39.7% (JIS) and in women was 15.7% (WHO), 20.7% (CDS), 54.2% (NCEP-ATP III), 51.5% (IDF) and 54.2% (JIS), respectively. Respective ORs (95% CI) for associating MetS with CHD in men were 1.79 (1.02-3.17), 1.25 (0.69-2.26), 1.61 (1.01-2.58), 1.84 (1.14-2.96), and 1.53 (0.96-2.43). Corresponding ORs (95% CI) for stroke in men were 2.18 (95% CI 1.20 to 3.97), 2.20 (95% CI 1.25 to 3.89), 1.71 (95% CI 1.02 to 2.84), 1.30 (95% CI 0.77 to 2.23), and 1.61 (95% CI 0.97 to 2.68), respectively. In women, CHD and stroke were significantly associated with MetS using all five definitions of MetS. In addition, PAD was associated with all five MetS definitions in men, but not in women. Only hyperglycemia and BMI were significantly associated with PAD in women.

CONCLUSIONS

In this rural Chinese population, the JIS, IDF and CDS criteria may not be more suitable than WHO and updated NCEP-ATPIII definitions for screening high-risk individuals and estimating the risk of CHD and stroke from MetS, especially in men.

Mo2Ga2C: a new ternary nanolaminated carbide

We report the discovery of a new hexagonal Mo₂Ga₂C phase, wherein two Ga layers – instead of one – are stacked in a simple hexagonal arrangement in between Mo₂C layers.

In vivo characterization of the highly selective monoacylglycerol lipase inhibitor KML29: antinociceptive activity without cannabimimetic side effects

BACKGROUND AND PURPOSE

Since monoacylglycerol lipase (MAGL) has been firmly established as the predominant catabolic enzyme of the endocannabinoid 2-arachidonoylglycerol (2-AG), a great need has emerged for the development of highly selective MAGL inhibitors. Here, we tested the in vivo effects of one such compound, KML29 (1,1,1,3,3,3-hexafluoropropan-2-yl 4-(bis(benzo[d][1,3]dioxol-5-yl)(hydroxy)methyl)piperidine-1-carboxylate).

EXPERIMENTAL APPROACH

In the present study, we tested KML29 in murine inflammatory (i.e. carrageenan) and sciatic nerve injury pain models, as well as the diclofenac-induced gastric haemorrhage model. KML29 was also evaluated for cannabimimetic effects, including measurements of locomotor activity, body temperature, catalepsy, and cannabinoid interoceptive effects in the drug discrimination paradigm.

KEY RESULTS

KML29 attenuated carrageenan-induced paw oedema and completely reversed carrageenan-induced mechanical allodynia. These effects underwent tolerance after repeated administration of high-dose KML29, which were accompanied by cannabinoid receptor 1 (CB1 ) receptor desensitization. Acute or repeated KML29 administration increased 2-AG levels and concomitantly reduced arachidonic acid levels, but without elevating anandamide (AEA) levels in the whole brain. Furthermore, KML29 partially reversed allodynia in the sciatic nerve injury model and completely prevented diclofenac-induced gastric haemorrhages. CB1 and CB2 receptors played differential roles in these pharmacological effects of KML29. In contrast, KML29 did not elicit cannabimimetic effects, including catalepsy, hypothermia and hypomotility. Although KML29 did not substitute for Δ(9) -tetrahydrocannabinol (THC) in C57BL/6J mice, it fully and dose-dependantly substituted for AEA in fatty acid amide hydrolase (FAAH) (-/-) mice, consistent with previous work showing that dual FAAH and MAGL inhibition produces THC-like subjective effects.

CONCLUSIONS AND IMPLICATIONS

These results indicate that KML29, a highly selective MAGL inhibitor, reduces inflammatory and neuropathic nociceptive behaviour without occurrence of cannabimimetic side effects.

LINKED ARTICLES

This article is part of a themed section on Cannabinoids 2013. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-6.

Association between polymorphisms of complement pathway genes and age-related macular degeneration in a Chinese population

PURPOSE

We assessed the association between complement pathway genes and age-related macular degeneration (AMD) in a Chinese population.

METHODS

In a case-control study, 165 AMD patients and 216 unrelated controls were recruited from two hospitals in central China. We selected and genotyped six single nucleotide polymorphisms (SNPs) of four complement pathway genes, including rs800292 and rs1410996 of complement H (CFH), rs9332739 of complement 2 (C2), rs4151667 of complement factor B (CFB), and rs2241394 and rs2230199 of complement 3 (C3). The associations between SNPs and AMD, adjusted by age and sex, were assessed by using logistic regression models and haplotype association analysis.

RESULTS

In our study, two SNPs of CFH and their haplotypes were associated significantly with AMD, and the adjusted odd ratios (ORs) were 2.45 (95% confidence interval [CI] 1.25-4.79) for rs800292 (genotype GG versus AA), 2.49 (95% CI 1.24-5.00) for rs1410996 (genotype TT versus CC), and 4.45 (95% CI 2.32-8.55) for haplotype block of rs800292-rs1410996 (haplotype G-C versus A-C), respectively. The haplotype of C2/CFB also was associated significantly with AMD, and the adjusted OR was 8.86 (95% CI 1.88-41.69) for the haplotype block of rs9332739-rs4151667 (haplotype G-A versus G-T), though no relationship was found in genotype association analysis of the two SNPs of C2/CFB. With the sample size of our study, no relationship was found for AMD and the two SNPs of C3.

CONCLUSIONS

Gene variants in CFH and C2/CFB contribute to AMD in the Chinese population.

ADAMTS9 is a functional tumor suppressor through inhibiting AKT/mTOR pathway and associated with poor survival in gastric cancer

Using genome-wide promoter methylation analysis, we identified a disintegrin-like and metalloprotease with thrombospondin type 1 motif 9 (ADAMTS9) is methylated in cancer. We aim to clarify its epigenetic inactivation, biological function and clinical implication in gastric cancer. ADAMTS9 was silenced in 6 out of 8 gastric cancer cell lines. The loss of ADAMTS9 expression was regulated by promoter hypermethylation and could be restored by demethylation agent. Ectopic expression of ADAMTS9 in gastric cancer cell lines (AGS, BGC823) inhibited cell growth curve in both the cell lines (P<0.0001), suppressed colony formation (P<0.01) and induced apoptosis (P<0.001 in AGS, P<0.01 in BGC823). Moreover, conditioned culture medium from ADAMTS9-transfected cell lines significantly disrupted the human umbilical vein endothelial cell tube formation capacity on Matrigel (P<0.01 in AGS, P<0.001 in BGC823). The in vivo growth of ADAMTS9 cells in nude mice was also markedly diminished after stable expression of ADAMTS9 (P<0.001). On the other hand, ADAMTS9 knockdown promoted cell proliferation (P<0.001). We further revealed that ADAMTS9 inhibited tumor growth by blocking activation of Akt and its downstream target the mammalian target of rapamycin (mTOR). ADAMTS9 also reduced phosphorylation of mTOR downstream targets p70 ribosomal S6 kinase, eIF4E-binding protein and downregulated hypoxia-inducible factor-1α. Therefore, this is the first demonstration that ADAMTS9 is a critical tumor suppressor of gastric cancer progression at least in part through suppression of oncogenic AKT/mTOR signaling. Moreover, promoter methylation of ADAMTS9 was detected in 29.2% (21/72) of primary gastric tumors. Multivariate analysis showed that patients with ADAMTS9 methylation had a poorer overall survival (relative risk (RR)=2.788; 95% confidence interval, 1.474-5.274; P=0.002). Kaplan-Meier survival curves showed that ADAMTS9 methylation was significantly associated with shortened survival in gastric cancer patients (P=0.001, log-rank test). In conclusion, ADAMTS9 acts as a functional tumor suppressor in gastric cancer through inhibiting oncogenic AKT/mTOR signaling pathway. Methylation of ADAMTS9 is an independent prognostic factor of gastric cancer.

Genetic analysis of NR4A2 gene in a large population of Han Chinese patients with Parkinson's disease

BACKGROUND

NR4A2 gene is a transcription factor crucial for differentiation and survival of midbrain dopamine (DA) neurons, and several variants have been eported to be associated with Parkinson's disease (PD) in the Caucasian population.

METHODS

To determine whether there is any association of NR4A2 mutation or variation with PD in the Han Chinese population, we performed a genetic analysis of all the exons and exon-intron boundaries in 689 PD patients and 672 controls from mainland China using direct sequencing analysis.

RESULTS

We identified four novel variants and two previously reported variants. Two novel variants (exon 2 c.-20 C>G and exon 3 c.711 C>A) were only found in PD. The others (exon 2 c.-35 A>G; exon 8 c.1615 G>A; intron 4 IVS4-16 G>T; and intron 6 IVS6 + 18 insG) were found in both PD and controls at different frequencies.

CONCLUSIONS

Collectively, our results suggest that NR4A2 may be a susceptibility gene for PD in the Chinese population.

Long-term efficacy and tolerability of a fixed-dose combination of antihypertensive agents: an open-label surveillance study in China

BACKGROUND

A fixed-dose combination (FDC) of four compounds, hydrochlorothiazide 12.5 mg, triamterene 12.5 mg, dihydralazine 12.5 mg and reserpine 0.1 mg (HTDR), is widely used as an antihypertensive treatment in China. Although HTDR has been used in China for more than 30 years, there have been few comprehensive evaluations of this treatment.

OBJECTIVE

The aim of this study was to investigate the long-term efficacy and tolerability of HTDR in Chinese patients with essential hypertension.

METHODS

This was a 36-month, community-based, open-label surveillance study, conducted in the Huangpu District (Shanghai, China). The study was based in local primary healthcare settings. Subjects were recruited if they had essential hypertension, were aged ≥35 years at the time of enrolment, were expected to remain in the area for 3 years, and were able to provide informed consent. Patients who had secondary hypertension, myocardial infarction or stroke within 6 months of screening, impaired renal or hepatic function, history of cardiomyopathy or chronic heart failure, or were pregnant or lactating were excluded. HTDR was administered as one or two tablets per day in the morning. If necessary, additional hydrochlorothiazide was added. Blood pressure (BP) was measured at baseline and throughout the 36-month surveillance period every 3 months. Biochemical indicators (e.g. fasting blood glucose, plasma lipid parameters, plasma sodium and potassium, plasma uric acid and serum creatinine) were also measured, and adverse events were noted. BP reductions and the rate at which patients achieved BP targets (systolic BP [SBP] <140 mmHg and diastolic BP [DBP] <90 mmHg) throughout the period were determined. Subgroup analyses by sex and age were also conducted.

RESULTS

A total of 1529 patients (550 male, 979 female; mean age 65.7 years) entered the study. After the 36-month treatment period, 93.1% of patients had achieved the SBP target, 97.9% had achieved the DBP target, and 92.1% had achieved both. The mean decreases in SBP and DBP were 15.3 mmHg and 9.9 mmHg, respectively. Overall, 127 adverse events in 119 patients (7.8%) occurred during the follow-up period, most of which were mild to moderate. Plasma lipid profiles were improved after 24 months of treatment. In addition, a significant increase in plasma potassium and a significant reduction in plasma uric acid were seen.

CONCLUSION

HTDR was found to have good long-term efficacy and tolerability in Chinese patients with essential hypertension.

[Dietary patterns and hypertension among adults in Taiwan]

OBJECTIVE

To explore the relationship between dietary pattern and hypertension in Taiwan adults.

METHODS

According to the inclusion criteria, a total of 65 140 subjects aged 20-75 years who participating health examination in the Meizhao health centers in Taiwan were included in 2006. The food intake and lifestyle pattern of them were accessed. The identification of hypertension was based on the diagnostic criteria from JNC-VII. Factor analysis and multivariate logistic regression model was used to explore the associations of dietary patterns with hypertension for males and females.

RESULTS

Four dietary patterns were identified, namely "high protein" pattern, "prudent" pattern, "western" pattern, and "egg and dairy foods" pattern. After age, gender, BMI, physical activity, education level, smoking and alcohol intake being adjusted, relative to the "western" pattern, the risk of hypertension in males with "prudent", "high protein" and egg and dairy foods" patterns were significantly lower, the OR were 0. 95 (95% CI 0. 92 - 0.98), 0.97 (95% CI 0.94 - 0.99) and 0.94 (95% CI 0.91 - 0.97), respectively. Significant lower risk of hypertension in females for the "high protein" pattern group was found, with OR of 0.96 (95% CI 0. 2 -0.99).

CONCLUSION

Our results indicated that increasing the intake of protein, dairy products, vegetables and fruit was related to a reduction of high blood pressure risk, especially in men.

Uric acid and incident chronic kidney disease in a large health check-up population in Taiwan

AIM

Uric acid (UA) is strongly associated with the confirmed chronic kidney disease (CKD) risk factors, such as hypertension, diabetes and metabolic syndrome (MS); however, whether higher UA is independently associated with CKD is still debatable. Other studies found that low UA level may reflect inadequate protection against oxidant-mediated stress; it is also unknown whether hypouricemia may have a harmful effect on the kidney. No studies have examined whether there is a J-shaped relationship between UA and incident CKD.

METHODS

The association between UA and incident kidney disease (Glomerular filtration rate <60 mL/min per 1.73 m(2) ) was examined among 94 422 Taiwanese participants, aged ≥20 years with a mean 3.5 years follow-up in a retrospective cohort. The association between UA and CKD was evaluated using Cox models with adjustment for confounders.

RESULTS

The adjusted hazard ratio (HR) for incident CKD was 1.03 (95% confidence interval (CI), 1.01 to 1.06) for baseline UA level (increase by 1 mg/dL). Compared with serum UA in the first quintile (2.0 to 4.5 mg/dL), the multivariate-adjusted HR for CKD of the fifth (≥7.3 mg/dL), fourth (6.3 to 7.2 mg/dL), third (5.5 to 6.2 mg/dL), second (4.6 to 5.4 mg/dL) and hyopuricemia (<2.0 mg/dL) were 1.15 (95%CI, 1.01-1.30), 0.98 (95%CI, 0.87-1.10), 1.06 (95%CI, 0.94-1.19), 1.02 (95%CI, 0.91-1.14) and 1.65(95%CI, 0.53-5.15), respectively. The tests for the non-linear association were all not significant for both male and female. Gender-specific model revealed only the UA above 7.3 mg/dL with the increased risk of new-onset CKD in males.

CONCLUSION

Hyperuricemia is a risk factor for CKD in Taiwan, future studies are still necessary to determine whether hypouricemia increases the risk of CKD.

The impact of socioeconomic status on the incidence of metabolic syndrome in a Taiwanese health screening population

OBJECTIVES

The purpose of this study was to estimate the incidence of metabolic syndrome (MS) in a 5-year follow-up adult population in Taiwan who were examined at the Major Health Screening Center, and to assess possible socioeconomic determinants of the syndrome in this sample.

METHODS

The longitudinal study included 9,389 adults, aged 35-74 years, who visited the Major Health Screening Center from 1998-2002, and were followed up for 5 years.

RESULTS

The 5-year cumulative incidence of MS in this sample was 11.37%, and the weighted incidence was 12.46%; 14.95% for men and 9.89% for women, respectively. After adjustment for behavioral and habits, family history, gender and age, education level was associated with the incidence of MS. With middle school and lower as a baseline, the incidence of MS for high school, junior college, and college and above was OR 0.80, 95% CI 0.64-1.00; OR 0.80, 95% CI 0.62-1.03 and OR 0.65, 95% CI 0.50-0.83, respectively.

CONCLUSIONS

The standardized cumulative incidence of MS was 12.46%. Lower education level was an important socioeconomic determinant of MS in women.

Decreased NURR1 and PITX3 gene expression in Chinese patients with Parkinson's disease

BACKGROUND AND PURPOSE

The preferential degeneration of midbrain dopaminergic (mDA) neurons in the substantia nigra pars compacta is the pathological hallmark in Parkinson's disease (PD). The transcription factors NURR1 and PITX3 have been shown to play a crucial role in the maturation and survival of mDA neurons, and both of them were potential susceptibility genes for PD.

METHODS

  To determine whether NURR1 and PITX3 gene expression are altered in Chinese patients with PD, we measured their gene expression in human peripheral blood lymphocytes (PBL) in 255 patients with PD and 211 age- and gender-matched healthy controls by quantitative real-time PCR technique.

RESULTS

 We found that both NURR1 and PITX3 gene expression in PBL were significantly decreased in patients with PD as compared with controls (P < 0.0001). Lower levels of NURR1 and PITX3 gene expression were significantly associated with the increased risk for PD in male and older subjects, respectively.

CONCLUSIONS

  Our results provide useful information that the NURR1 and PITX3 gene expression is decreased in the PBL of Chinese patients with PD, indicating their possible systemic involvement in PD.

Epigenetic inactivation of paired box gene 5, a novel tumor suppressor gene, through direct upregulation of p53 is associated with prognosis in gastric cancer patients

Using genome-wide methylation screening, we identified that paired box gene 5 (PAX5) is involved in human cancer development. However, the function of PAX5 in gastric cancer (GC) development is largely unclear. We analyzed its epigenetic inactivation, biological functions and clinical application in GC. PAX5 was silenced in seven out of eight GC cell lines. A significant downregulation was also detected in paired gastric tumors compared with adjacent non-cancerous tissues. The downregulation of PAX5 was closely linked to the promoter hypermethylation status and could be restored with demethylation treatment. Ectopic expression of PAX5 in silenced GC cell lines (AGS and BGC823) inhibited colony formation and cell viability, arrested cell cycle, induced apoptosis, suppressed cell migration and invasion and repressed tumorigenicity in nude mice. Consistent with the induction of apoptosis by PAX5 in vitro, terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) staining showed significantly enhanced apoptotic cells in PAX5-expressed tumors compared with the vector control tumors. On the other hand, knockdown of PAX5 by PAX5-short hairpin RNA increased the cell viability and proliferation. The anti-tumorigenic function of PAX5 was revealed to be mediated by upregulating downstream targets of tumor protein 53 (p53), p21, BCL2-associated X protein, metastasis suppressor 1 and tissue inhibitors of metalloproteinase 1, and downregulating BCL2, cyclin D1, mesenchymal-epithelial transition factor (MET) and matrix metalloproteinase 1. Immunoprecipitation assay demonstrated that PAX5 directly bound to the promoters of p53 and MET. Moreover, PAX5 hypermethylation was detected in 77% (144 of 187) of primary GCs compared with 10.5% (2/19) of normal gastric tissues (P<0.0001). GC patients with PAX5 methylation had a significant poor survival compared with the unmethylated cases as demonstrated by Cox regression model and log-rank test. In conclusion, PAX5 is a novel functional tumor suppressor in gastric carcinogenesis. Detection of methylated PAX5 can be utilized as an independent prognostic factor in GC.

A novel isoform of the 8p22 tumor suppressor gene DLC1 suppresses tumor growth and is frequently silenced in multiple common tumors

The critical 8p22 tumor suppressor deleted in liver cancer 1 (DLC1) is frequently inactivated by aberrant CpG methylation and/or genetic deletion and implicated in tumorigeneses of multiple tumor types. Here, we report the identification and characterization of its new isoform, DLC1 isoform 4 (DLC1-i4). This novel isoform encodes an 1125-aa (amino acid) protein with distinct N-terminus as compared with other known DLC1 isoforms. Similar to other isoforms, DLC1-i4 is expressed ubiquitously in normal tissues and immortalized normal epithelial cells, suggesting a role as a major DLC1 transcript. However, differential expression of the four DLC1 isoforms is found in tumor cell lines: Isoform 1 (longest) and 3 (short thus probably nonfunctional) share a promoter and are silenced in almost all cancer and immortalized cell lines, whereas isoform 2 and 4 utilize different promoters and are frequently downregulated. DLC1-i4 is significantly downregulated in multiple carcinoma cell lines, including 2/4 nasopharyngeal, 8/16 (50%) esophageal, 4/16 (25%) gastric, 6/9 (67%) breast, 3/4 colorectal, 4/4 cervical and 2/8(25%) lung carcinoma cell lines. The functional DLC1-i4 promoter is within a CpG island and is activated by wild-type p53. CpG methylation of the DLC1-i4 promoter is associated with its silencing in tumor cells and was detected in 38-100% of multiple primary tumors. Treatment with 5-aza-2'-deoxycytidine or genetic double knockout of DNMT1 and DNMT3B led to demethylation of the promoter and reactivation of its expression, indicating a predominantly epigenetic mechanism of silencing. Ectopic expression of DLC1-i4 in silenced tumor cells strongly inhibited their growth and colony formation. Thus, we identified a new isoform of DLC1 with tumor suppressive function. The differential expression of various DLC1 isoforms suggests interplay in modulating the complex activities of DLC1 during carcinogenesis.

Mutations in the beta-myosin heavy chain gene in southern Chinese families with hypertrophic cardiomyopathy

In this study, 14 unrelated hypertrophic cardiomyopathy (HCM) probands were scanned by polymerase chain reaction-single-strand conformation polymorphism analysis and DNA sequencing. Three mis-sense mutations of the beta-myosin heavy chain gene, MYH7, were found: valine (Val) 606 methionine (Met), arginine (Arg) 694 leucine (Leu), and Arg 723 glycine (Gly). All are reported here for the first time in Chinese subjects. The results showed that: Val606Met is an intermediate malignancy mutation; Arg694Leu is a novel mutation with a benign phenotype; and the Arg723Gly mutation is linked to malignancy - it can lead not only to HCM but also to dilated cardiomyopathy at various ages. The clinical symptoms associated with Arg723Gly emerged early and caused more severe clinical manifestation and poorer prognosis in females than in males. Mis-sense mutations were not detected in the myosin binding protein C, cardiac, cardiac troponin T type 2, or cardiac troponin I type 3 genes. The MYH7 gene may be an HCM mutation hotspot in the Chinese and have unique features in this study population.

Metabolic syndrome and the development of chronic kidney disease among 118 924 non-diabetic Taiwanese in a retrospective cohort

AIM

Metabolic syndrome (MetS) is a common risk factor for cardiovascular and chronic kidney disease (CKD) in Western populations; however, no prospective studies have examined MetS as a risk factor for CKD in Chinese adults.

METHODS

The incidence of CKD and the prospective link between MetS (defined by two criteria: modified Adult Treatment Panel III (ATP-III) and the International Diabetes Federation (IDF)) and CKD among 118,924 Taiwanese participants without baseline diabetes, aged 20-74 years with a mean 3.7 years follow up, was examined. CKD was measured by using estimated glomerular filtration rate or dipstick proteinuria (1+). The association between MetS or combination patterns of MetS abnormalities and CKD was evaluated using Cox models with adjustment for confounders.

RESULTS

The incidence of CKD was 288/10,000 person-years (95% confidence interval (CI), 283-293). The findings showed that central obesity (OB), high blood pressure (BP) and high triglyceride were considered to be the major metabolic events in the study cohort. Incidences and hazard ratios (HR) on CKD had evidently increasing trends with the number of MetS components. The multivariable-adjusted HR for CKD associated with ATP-III-MetS was 1.30 (95% CI, 1.24-1.36). Equivalent HR for IDF-MetS were 1.37 (95% CI, 1.30-1.44). The associations were still observed when analyzing by stratifying incident diabetes and adjusting hypertension status.

CONCLUSION

MetS induces an increased risk for CKD independent of baseline confounding factors and subsequent incident diabetes modified the associations lightly. The mechanism through which MetS may cause CKD in this population likely is the development of multiple metabolic pathogenic processes together.

ARRDC3 suppresses breast cancer progression by negatively regulating integrin beta4

Large-scale genetic analyses of human tumor samples have been used to identify novel oncogenes, tumor suppressors and prognostic factors, but the functions and molecular interactions of many individual genes have not been determined. In this study we examined the cellular effects and molecular mechanism of the arrestin family member, ARRDC3, a gene preferentially lost in a subset of breast cancers. Oncomine data revealed that the expression of ARRDC3 decreases with tumor grade, metastases and recurrences. ARRDC3 overexpression represses cancer cell proliferation, migration, invasion, growth in soft agar and in vivo tumorigenicity, whereas downregulation of ARRCD3 has the opposite effects. Mechanistic studies showed that ARRDC3 functions in a novel regulatory pathway that controls the cell surface adhesion molecule, β-4 integrin (ITGβ4), a protein associated with aggressive tumor behavior. Our data indicates ARRDC3 directly binds to a phosphorylated form of ITGβ4 leading to its internalization, ubiquitination and ultimate degradation. The results identify the ARRCD3-ITGβ4 pathway as a new therapeutic target in breast cancer and show the importance of connecting genetic arrays with mechanistic studies in the search for new treatments.

Superconductivity induced by Ni doping in SmFe(1-x)Ni(x)AsO

Superconductivity with a T(c) of about 10 K is observed in the Ni-doped SmFe(1-x)Ni(x)AsO system. The measurements of resistivity and magnetic susceptibility show that the spin-density wave (SDW) order is quickly suppressed with increasing Ni content, and superconductivity emerges as x≥0.04. T(c)(mid) shows a maximum of 10.8 K at x = 0.06, and it drops to lower than 2 K as x>0.12. Meanwhile, the upper critical field (H(c2)(0)) is estimated to be about 40 T for the optimally-doped sample (x = 0.06). The normal state thermopower is negative for all the Ni-doped samples, indicating that an electron-type charge carrier dominates in the transport properties. Moreover, the magnitude of the room-temperature thermopower increases with increasing Ni content, and then shows a broad peak around x = 0.06. We found that there is an obvious correlation between the anomalously enhanced thermopower and superconductivity. A phase diagram is derived based on the transport measurements and a dome-like T(c)(x) curve is established.

Meta-analysis of the association of the HTRA1 polymorphisms with the risk of age-related macular degeneration

HTRA1 was considered as one of important age-related macular degeneration (AMD) candidate genes. However, due to population heterogeneity and bias from case-control study, the association between HTRA1 and AMD needs further confirmation across different studies in different population. In this study, a meta-analysis was performed in 14 case-control studies which were published before August 31, 2008. Effect of HTRA1 polymorphism with AMD was synthetically evaluated. The pooled odds ratio (OR) for heterozygous genotype GA versus wild homozygous genotype GG is 2.13 (95% CI: 1.90, 2.39), the OR of homozygous genotype AA versus GG is 6.92 (95% CI: 5.74, 8.34) and the OR of allele A carrier (GA+AA) versus GG is 3.02 (95% CI: 2.57, 3.53). Sub-analysis indicated that the risk of HTRA1 rs11200638 on wet AMD was stronger than dry AMD, and it seems that HTRA1 rs11200638 could increase the risk of AMD in all races. This study strengthens the hypothesis of association between rs11200638 in the promoter of HTRA1 polymorphism and AMD. The variant of HTRA1/625G-->A could be a potentially promising genetic biomarker of AMD.

An accurate risk score for estimation 5-year risk of type 2 diabetes based on a health screening population in Taiwan

This study aimed to provide the epidemiological model evaluating the risk of developing type 2 diabetes (T2DM) in Taiwan periodic health-check population. We derived risk functions using multivariate Cox regression in a random half of the sample. Rules based on these risk functions were evaluated in another half. Model coefficients were used to assign each variable a score. 73,961 subjects aged 35-74, were included and followed up with a median 3.15 years. Six predictive models (PMs) were developed. PM1 contained simple clinical information, while PM2 contained fasting plasma glucose (FPG) based on PM1, and PM3 further added variables indicating lipid level, liver and kidney. PM4 only included FPG. The capability of published ARIC score model was also evaluated. Eventually we considered score defined nine predictors by PM2. The area under the ROC curve (AUC) was 0.848 (95% CI, 0.829-0.868) predicting diabetes within 5 years, and also had adequate performance in validation subsample (AUC=0.833, 95% CI, 0.811-0.855). The 5-year T2DM probability can be calculated by: 1-0.9743960037 exp((score points -15.0281284)). We concluded that this diabetes risk score, derived from clinical information combined with FPG is a simple, effective tool to identify individuals at high risk for undiagnosed T2DM.

Phospholipase C delta 1 is a novel 3p22.3 tumor suppressor involved in cytoskeleton organization, with its epigenetic silencing correlated with high-stage gastric cancer

Located at the important tumor suppressor locus, 3p22, PLCD1 encodes an enzyme that mediates regulatory signaling of energy metabolism, calcium homeostasis and intracellular movements. We identified PLCD1 as a downregulated gene in aerodigestive carcinomas through expression profiling and epigenetic characterization. We found that PLCD1 was expressed in all normal adult tissues but low or silenced in 84% (16/19) gastric cancer cell lines, well correlated with its CpG island (CGI) methylation status. Methylation was further detected in 62% (61/98) gastric primary tumors, but none of normal gastric mucosa tissues. PLCD1 methylation was significantly correlated with tumor high stage. Detailed methylation analysis of 37 CpG sites at the PLCD1 CGI by bisulfite genomic sequencing confirmed its methylation. PLCD1 silencing could be reversed by pharmacological demethylation with 5-aza-2'-deoxycytidine, indicating a direct epigenetic silencing. Ectopic expression of PLCD1 in silenced gastric tumor cells dramatically inhibited their clonogenicity and migration, possibly through downregulating MMP7 expression and hampering the reorganization of cytoskeleton through cofilin inactivation by phosphorylation. Thus, epigenetic inactivation of PLCD1 is common and tumor-specific in gastric cancer, and PLCD1 acts as a functional tumor suppressor involved in gastric carcinogenesis.

DLEC1 is a functional 3p22.3 tumour suppressor silenced by promoter CpG methylation in colon and gastric cancers

Promoter CpG methylation of tumour suppressor genes (TSGs) is an epigenetic biomarker for TSG identification and molecular diagnosis. We screened genome wide for novel methylated genes through methylation subtraction of a genetic demethylation model of colon cancer (double knockout of DNMT1 and DNMT3B in HCT116) and identified DLEC1 (Deleted in lung and oesophageal cancer 1), a major 3p22.3 TSG, as one of the methylated targets. We further found that DLEC1 was downregulated or silenced in most colorectal and gastric cell lines due to promoter methylation, whereas broadly expressed in normal tissues including colon and stomach, and unmethylated in expressing cell lines and immortalised normal colon epithelial cells. DLEC1 expression was reactivated through pharmacologic or genetic demethylation, indicating a DNMT1/DNMT3B-mediated methylation silencing. Aberrant methylation was further detected in primary colorectal (10 out of 34, 29%) and gastric tumours (30 out of 89, 34%), but seldom in paired normal colon (0 out of 17) and gastric (1 out of 20, 5%) samples. No correlation between DLEC1 methylation and clinical parameters of gastric cancers was found. Ectopic expression of DLEC1 in silenced HCT116 and MKN45 cells strongly inhibited their clonogenicity. Thus, DLEC1 is a functional tumour suppressor, being frequently silenced by epigenetic mechanism in gastrointestinal tumours.

Down-regulation of ATM protein in HRS cells of nodular sclerosis Hodgkin's lymphoma in children occurs in the absence ofATMgene inactivation

The tumour component of classical Hodgkin's lymphoma (cHL), Hodgkin Reed-Sternberg (HRS) cells, are believed to be derived from germinal centre (GC) B cells but intriguingly display a characteristic loss of B cell receptor (BCR) expression. The precise mechanisms by which BCR-negative HRS cell progenitors survive negative selection during the GC reaction remain obscure. Individuals with ataxia telangiectasia, caused by biallelic inactivation of the DNA damage response gene, ataxia telangiectasia mutated (ATM), have a higher risk of cHL development. Here we show that, in contrast to normal GC B cells that expressed low but detectable ATM protein, ATM protein was not detected in HRS cells of 17/18 cases of paediatric cHL, all but one with nodular sclerosis (NS) subtype. A comprehensive analysis of the ATM gene in microdissected HRS cells of nine representative tumours showed no evidence of either loss of heterozygosity or consistent pathogenic mutations. Furthermore, bisulphite sequencing of the ATM promoter from HRS cells of five tumours also revealed the absence of hypermethylation. Since our microarray data suggested significantly reduced ATM transcription in HRS cells compared to GC B cells, we conclude that loss of ATM expression could be the result of alterations in upstream regulators of ATM transcription. Importantly, ATM loss in paediatric cHLs has clinical implications and could be potentially exploited to guide future, less toxic, tumour-specific treatments.

Frequent epigenetic inactivation of secreted frizzled-related protein 2 (SFRP2) by promoter methylation in human gastric cancer

The role of secreted frizzled-related protein (SFRP) genes in gastric cancer remains largely unknown. We determined the frequency and functional significance of SFRPs hypermethylation in human gastric cancer. The expression and methylation status of four SFRP members (SFRP1, 2, 4, and 5) in primary gastric cancer samples was screened. The biological effects of SFRP were analysed by flow cytometry, cell viability assay and in vivo tumour growth in nude mice. Among the four SFRPs, only SFRP2 was significantly downregulated in gastric cancer as compared to adjacent non-cancer samples (P<0.01). Promoter hypermethylation of SFRP2 was detected in 73.3% primary gastric cancer tissues, 37.5% of samples showing intestinal metaplasia and 20% adjacent normal gastric tissues. Bisulphite DNA sequencing confirmed the densely methylated SFRP2 promoter region. Demethylation treatment restored the expression of SFRP2 in gastric cancer cell lines. Forced expression of SFRP2 induced cell apoptosis, inhibited proliferation of gastric cancer cells and suppressed tumour growth in vivo. Moreover, methylated SFRP2 was detected in 66.7% of serum samples from cancer patients but not in normal controls. In conclusion, epigenetic inactivation of SFRP2 is a common and early event contributing to gastric carcinogenesis and may be a potential biomarker for gastric cancer.

Possible correlation between SOCS1 methylation and EGFR exon 19 mutation but not exon 21 mutation in Chinese NSCLC patients

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Background: Suppressor of cytokine signaling-1 (SOCS1) and -3 (SOCS3) interact with the epidermal growth factor receptor (EGFR) to bring about the ubiquination and degradation of the receptor. Silencing of SOCS1 and SOCS3 by methylation was postulated to regulate the IL-6R/JAK-mediated STAT3 activation. Its relationship to EGFR and EGFR mutations in lung cancer remains unclear. Here, we examined the relationship between EGFR mutations and methylation of SOCS1 and SOCS3 in Chinese NSCLC patients. Methods: EGFR mutations were assessed in DNAs from microdissected tumor cells. PCR products were purified and sequenced using the BigDye Terminator Cycle Sequencing Kit (Applied Biosystem) and the ABI 3100 Genetic Analyzer. For methylation analyses of SOCS1 and SOCS3, DNAs were extracted from paraffin sections of tumor tissues, bisulfite treated and analyzed by methylation- specific PCR (MSP). Results: Data is available from 9 lung cancer cell lines and 20 tumor samples. Five EGFR-wild type cell lines had methylation for SOCS1. We found EGFR exon 19 mutation in 5 (25%) tumors, exon 21 mutation (L858R) in 2 (10%) tumors, and 1 (5%) tumor had double mutations. Four of 5 (80%) tumors with exon 19 mutation and none (0%) of the tumors with exon 21 mutation had SOCS1 methylation, comparing to only 2 of 12 (17%) EGFR-wild type tumors had SOCS1 methylation. SOCS3 methylation was not detected in any of the primary tumors or cell lines. Conclusions: Our preliminary findings suggest that SOCS1 methylation might be positively correlated with EGFR exon 19 mutation but exclusive from exon 21 mutation. A following study with larger sample size is currently under way. SOCS1 methylation may explain the better tumor response associated with EGFR exon 19 mutation.

No significant financial relationships to disclose.

Identification of a novel tumor transforming gene GAEC1 at 7q22 which encodes a nuclear protein and is frequently amplified and overexpressed in esophageal squamous cell carcinoma

By comparative DNA fingerprinting, we identified a 357-bp DNA fragment frequently amplified in esophageal squamous cell carcinomas (ESCC). This fragment overlaps with an expressed sequence tag mapped to 7q22. Further 5' and 3'-rapid amplification of cDNA ends revealed that it is part of a novel, single-exon gene with full-length mRNA of 2052 bp and encodes a nuclear protein of 109 amino acids ( approximately 15 kDa). This gene, designated as gene amplified in esophageal cancer 1 (GAEC1), was located within a 1-2 Mb amplicon at 7q22.1 identified by high-resolution 1 Mb array-comparative genomic hybridization in 6/10 ESCC cell lines. GAEC1 was ubiquitously expressed in normal tissues including esophageal and gastrointestinal organs; with amplification and overexpression in 6/10 (60%) ESCC cell lines and 34/99 (34%) primary tumors. Overexpression of GAEC1 in 3T3 mouse fibroblasts caused foci formation and colony formation in soft agar, comparable to H-ras and injection of GAEC1-transfected 3T3 cells into athymic nude mice formed undifferentiated sarcoma in vivo, indicating that GAEC1 is a transforming oncogene. Although no significant correlation was observed between GAEC1 amplification and clinicopathological parameters and prognosis, our study demonstrated that overexpressed GAEC1 has tumorigenic potential and suggest that overexpressed GAEC1 may play an important role in ESCC pathogenesis.

Celecoxib reduces microvessel density in patients treated with nasopharyngeal carcinoma and induces changes in gene expression

BACKGROUND

Celecoxib is a selective cyclooxygenase-2 inhibitor with antitumor and antiangiogenic activity. We sought to determine pharmacodynamic change in tumors of patients with nasopharyngeal carcinoma (NPC) treated with celecoxib.

METHODS

Tumor biopsies were obtained before and after treatment with celecoxib 400 mg b.i.d. for 14 days in patients with newly diagnosed, untreated NPC. Tumor angiogenesis and cell proliferation were assessed by immunohistochemistry and gene expression by microarray analysis. Plasma celecoxib concentrations were obtained on days 8 and 14.

RESULTS

Paired samples were analyzed in 15 patients. Microvessel density was reduced in post-treatment samples and mean celecoxib levels reached therapeutic levels. Thirty-five genes (27 down-regulated, eight up-regulated) were differentially expressed on microarray analysis (p < 0.001). Down-regulated genes included cell cycle regulation-related (cyclin-dependent kinase 2, YES1), transcription factor (TRIP-Br2), whereas the antigen processing and presentation-related gene HLA-DM B was up-regulated.

CONCLUSION

Celecoxib reduced angiogenesis and induced tumor transcriptional changes. Further characterization of these transcriptional changes in vivo is needed to provide further insights into the effects of celecoxib in neoplastic tissue. Our findings provide a rationale for clinical studies aimed at assessing the efficacy of celecoxib in the treatment of NPC.

The major 8p22 tumor suppressor DLC1 is frequently silenced by methylation in both endemic and sporadic nasopharyngeal, esophageal, and cervical carcinomas, and inhibits tumor cell colony formation

Identification of tumor suppressor genes (TSG) silenced by methylation uncovers mechanisms of tumorigenesis and identifies new epigenetic tumor markers for early cancer detection. Both nasopharyngeal carcinoma (NPC) and esophageal carcinoma are major tumors in Southern China and Southeast Asia. Through expression subtraction of NPC, we identified Deleted in Liver Cancer 1 (DLC1)/ARHGAP7 (NM_006094)--an 8p22 TSG as a major downregulated gene. Although expressed in all normal tissues, DLC1 was silenced or downregulated in 11/12 (91%) NPC, 6/15 (40%) esophageal, 5/8 (63%) cervical and 3/9 (33%) breast carcinoma cell lines. No genetic deletion of DLC1 was detected in NPC although a hemizygous deletion at 8p22-11 was found by 1-Mb array-CGH in some cell lines. We then located the functional DLC1 promoter by 5'-RACE and promoter activity assays. This promoter was frequently methylated in all downregulated cell lines and in a large collection of primary tumors including 89% (64/72) NPC (endemic and sporadic types), 51% (48/94) esophageal, 87% (7/8) cervical and 36% (5/14) breast carcinomas, but seldom in paired surgical marginal tissues and not in any normal epithelial tissue. The transcriptional silencing of DLC1 could be reversed by 5-aza-2'-deoxycytidine or genetic double knock-out of DNMT1 and DNMT3B. Furthermore, ectopic expression of DLC1 in NPC and esophageal carcinoma cells strongly inhibited their colony formation. We thus found frequent epigenetic silencing of DLC1 in NPC, esophageal and cervical carcinomas, and a high correlation of methylation with its downregulation, suggesting a predominant role of epigenetic inactivation. DLC1 appears to be a major TSG implicated in the pathogenesis of these tumors, and should be further tested as a molecular biomarker in patients with these cancers.

Functional epigenetics identifies a protocadherin PCDH10 as a candidate tumor suppressor for nasopharyngeal, esophageal and multiple other carcinomas with frequent methylation

Protocadherins constitute the largest subgroup in the cadherin superfamily of cell adhesion molecules. Their major functions are poorly understood, although some are implicated in nervous system development. As tumor-specific promoter methylation is a marker for tumor suppressor genes (TSG), we searched for epigenetically inactivated TSGs using methylation-subtraction combined with pharmacologic demethylation, and identified the PCDH10 CpG island as a methylated sequence in nasopharyngeal carcinoma (NPC). PCDH10 is broadly expressed in all normal adult and fetal tissues including the epithelia, though at different levels. It resides at 4q28.3--a region with hemizygous deletion detected by array-CGH in NPC cell lines; however, PCDH10 itself is not located within the deletion. In contrast, its transcriptional silencing and promoter methylation were frequently detected in multiple carcinoma cell lines in a biallelic way, including 12/12 nasopharyngeal, 13/16 esophageal, 3/4 breast, 5/5 colorectal, 3/4 cervical, 2/5 lung and 2/8 hepatocellular carcinoma cell lines, but not in any immortalized normal epithelial cell line. Aberrant methylation was further frequently detected in multiple primary carcinomas (82% in NPC, 42-51% for other carcinomas), but not normal tissues. The transcriptional silencing of PCDH10 could be reversed by pharmacologic demethylation with 5-aza-2'-deoxycytidine or genetic demethylation with double knockout of DNMT1 and DNMT3B, indicating a direct epigenetic mechanism. Ectopic expression of PCDH10 strongly suppressed tumor cell growth, migration, invasion and colony formation. Although the epigenetic and genetic disruptions of several classical cadherins as TSGs have been well documented in tumors, this is the first report that a widely expressed protocadherin can also function as a TSG that is frequently inactivated epigenetically in multiple carcinomas.

Delta9-tetrahydrocannbinol accounts for the antinociceptive, hypothermic, and cataleptic effects of marijuana in mice

Although it is widely accepted that delta9-tetrahydrocannabinol (delta9-THC) is the primary psychoactive constituent of marijuana, questions persist as to whether other components contribute to marijuana's pharmacological activity. The present experiments assessed the cannabinoid activity of marijuana smoke exposure in mice and tested the hypothesis that delta9-THC mediates these effects through a CB1 receptor mechanism of action. First, the effects of delta9-THC on analgesia, hypothermia, and catalepsy were compared with those of a marijuana extract with equated delta9-THC content after either i.v. administration or inhalation exposure. Second, mice were exposed to smoke of an ethanol-extracted placebo plant material or low-grade marijuana (with minimal delta9-THC but similar levels of other cannabinoids) that were impregnated with varying quantities of delta9-THC. To assess doses, delta9-THC levels in the blood and brains of drug-exposed mice were determined following both i.v. and inhalation routes of administration. Both marijuana and delta9-THC produced comparable levels of antinociception, hypothermia, and catalepsy regardless of the route of administration, and these effects were blocked by pretreatment with the CB1 antagonist SR141716 [N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide HCl]. Importantly, the blood and brain levels of delta9-THC were similar in mice exhibiting similar pharmacological effects, regardless of the presence of non-delta9-THC marijuana constituents. The present experiments provide evidence that the acute cannabinoid effects of marijuana smoke exposure on analgesia, hypothermia, and catalepsy in mice result from delta9-THC content acting at CB1 receptors and that the non-delta9-THC constituents of marijuana (at concentrations relevant to those typically consumed) influence these effects only minimally, if at all.

Effects of diltiazem on platelet activation and cytosolic calcium during percutaneous transluminal coronary angioplasty

AIMS

To evaluate effects of diltiazem on platelet hyper-reactivity in situations associated with endothelial injury and their possible relationship to cytosolic calcium concentration.

METHODS

Blood samples were collected at seven time points from 35 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) who received combined diltiazem and aspirin/ticlopidine therapy or aspirin/ticlopidine therapy alone. Platelet expression of glycoprotein IIb/IIIa and P-selectin, production of thromboxane B(2), and cytosolic calcium concentration were measured, respectively, by whole blood flow cytometry, radioimmunoassay, and fluorospectrophotometry. The effects of diltiazem of different concentrations on expression of glycoprotein IIb/IIIa and P-selectin were also studied in vitro in blood samples from patients with chronic stable angina.

RESULTS

Of the two treatments, aspirin/ticlopidine therapy did not prevent an acute increase of expression of glycoprotein IIb/IIIa and P-selectin and plasma thromboxane B(2) five minutes and 10 minutes after first inflation and 10 minutes after PTCA, whereas combined diltiazem and aspirin/ticlopidine therapy had a significant inhibitory effect. In the group receiving aspirin/ticlopidine therapy, there was a short term increase of platelet [Ca(2+)](i) immediately after PTCA which was significantly reduced by diltiazem treatment. Expression of glycoprotein IIb/IIIa and P-selectin was significantly inhibited in vitro by diltiazem in the concentration of 200 ng/ml or higher, but not 50 ng/ml.

CONCLUSIONS

Combined diltiazem and aspirin/ticlopidine therapy significantly inhibited platelet activation that continued in the presence of conventional aspirin/ticlopidine treatment. Antiplatelet effects of diltiazem were probably a consequence of reduction of platelet [Ca(2+)](i) and may only be achieved in higher than therapeutic concentrations.

One large-insert plant-transformation-competent BIBAC library and three BAC libraries of Japonica rice for genome research in rice and other grasses

We report one large-insert BIBAC library and three BAC libraries for japonica rice cv Nipponbare. The BIBAC library was constructed in the HindIII site of a plant-transformation-competent binary vector (pCLD04541) and the three BAC libraries were constructed in the BamHI, HindIII and EcoRI sites of a BAC vector (pECBAC1), respectively. Each library contains 23,040 clones, has an average insert size of 130 kb, 170 kb, 150 kb and 156 kb, and covers 6.7x, 8.7x, 7.7x and 8.0 x rice haploid genomes, respectively. The combined libraries contain 92,160 clones in total, covering 31.1 x rice haploid genomes. To demonstrate their utility, we screened the libraries with 55 DNA markers mapped to chromosome 8 of the rice genetic maps and analyzed a number of clones by the restriction fingerprinting and contig assembly method. The results indicate that the libraries completely cover the rice genome and, thus, are well-suited for genome research in rice and other gramineous crops. The BIBAC library represents the first plant-transformation-competent large-insert DNA library for rice, which will streamline map-based cloning, functional analysis of the rice genome sequence and molecular breeding in rice and other grass species. These libraries are being used in the development of a whole-genome, BAC/BIBAC-based, integrated physical, genetic and sequence map of rice and in the research of genome-wide comparative genomics of grass species.

Differential tramadol and O-desmethyl metabolite levels in brain vs. plasma of mice and rats administered tramadol hydrochloride orally

OBJECTIVE

To investigate a possible differential brain uptake of tramadol vs. its major metabolite (O-desmethyl tramadol; M1) in mice and rats.

METHODS

An extraction and measurement technique (gas chromatograph equipped with a nitrogen phosphorus detector) was used to measure plasma and brain levels of tramadol and M1 at intervals 10-300 min after oral dosing of tramadol hydrochloride to mice and rats.

RESULTS

For all doses of tramadol administered (5, 10, 20, or 40 mg/kg), tramadol and M1 plasma levels were greatest 10 min after dosing: in mice, peak tramadol plasma levels were 47.75-736.72 ng/mL and peak M1 levels were 75.30-1084.92 ng/mL; in rats, peak tramadol plasma levels were 185.03-455.81 ng/mL and peak M1 levels were 106.74-455.70 ng/mL. Tramadol brain levels were also greatest 10 min after dosing. In mice, peak tramadol brain levels were 226.42-1847.46 ng/g. Peak M1 levels (72.17-572.97 ng/g) occurred 20-60 min after dosing. In rats, peak tramadol brain levels were 258.50-1777.37 ng/g and peak M1 levels were 80.35-289.60 ng/g. In mice, the ratio of tramadol/M1 in plasma was 0.5-1.0 throughout the measurements, whereas the ratio in brain was about 10 at 10 min and about 2 from 20 to 50 min. In rats, the ratio of tramadol/M1 in plasma was 0.5-1.5, whereas the ratio in brain was about 15 at 10 min and about 4-7 thereafter.

CONCLUSION

In mice and rats, there appears to be preferential brain vs. plasma distribution of tramadol over M1.

Gas chromatographic method using nitrogen-phosphorus detection for the measurement of tramadol and its O-desmethyl metabolite in plasma and brain tissue of mice and rats

A method that allows the measurement of plasma and brain levels of the centrally-acting analgesic tramadol and its major metabolite (O-desmethyl tramadol) in mice and rats was developed using gas chromatography equipped with nitrogen-phosphorus detection (GC-NPD). Plasma samples were extracted with methyl tert.-butyl ether (MTBE) and were injected directly into the GC system. Brain tissue homogenates were precipitated with methanol, the resulting supernatant was dried then acidified with hydrochloric acid. The aqueous solution was washed with MTBE twice, alkalinized, and extracted with MTBE. The MTBE layer was dried, reconstituted and injected into the GC system. The GC assay used a DB-1 capillary column with an oven temperature ramp (135 to 179 degrees C at 4 degrees C/min). Dextromethorphan was used as the internal standard. The calibration curves for tramadol and O-desmethyl tramadol in plasma and brain tissue were linear in the range of 10 to 10000 ng/ml (plasma) and ng/g (brain). Assay accuracy and precision of back calculated standards were within +/- 15%.

An integrated map of Arabidopsis thaliana for functional analysis of its genome sequence

The genome of the model plant species Arabidopsis thaliana has recently been sequenced. To accelerate its current genome research, we developed a whole-genome, BAC/BIBAC-based, integrated physical, genetic, and sequence map of the A. thaliana ecotype Columbia. This new map was constructed from the clones of a new plant-transformation-competent BIBAC library and is integrated with the existing sequence map. The clones were restriction fingerprinted by DNA sequencing gel-based electrophoresis, assembled into contigs, and anchored to an existing genetic map. The map consists of 194 BAC/BIBAC contigs, spanning 126 Mb of the 130-Mb Arabidopsis genome. A total of 120 contigs, spanning 114 Mb, were anchored to the chromosomes of Arabidopsis. Accuracy of the integrated map was verified using the existing physical and sequence maps and numerous DNA markers. Integration of the new map with the sequence map has enabled gap closure of the sequence map and will facilitate functional analysis of the genome sequence. The method used here has been demonstrated to be sufficient for whole-genome physical mapping from large-insert random bacterial clones and thus is applicable to rapid development of whole-genome physical maps for other species.