Haplotype-based case-control study on human apurinic/apyrimidinic endonuclease 1/redox effector factor-1 gene and essential hypertension

BACKGROUND

Oxidative DNA damage is involved in the pathophysiology of essential hypertension (EH), which is a multifactorial disorder. Apurinic/apyrimidinic endonuclease 1/redox effector factor-1 (APE1/REF-1) is an essential endonuclease in the base excision repair pathway of oxidatively damaged DNA, in addition to having reducing properties that promote the binding of redox-sensitive transcription factors. Blood pressure in APE1/REF-1-knockout mice is reported to be significantly higher than in wild-type mice. The aim of this study was to investigate the relationship between EH and the human APE1/REF-1 gene through a haplotype-based case-control study using single-nucleotide polymorphisms (SNPs).

METHODS

We selected five SNPs in the human APE1/REF-1 gene (rs1760944, rs3136814, rs17111967, rs3136817, and rs1130409), and performed case-control studies in 265 EH patients and 266 age-matched normotensive (NT) subjects.

RESULTS

rs17111967 was found to show nonheterogeneity among Japanese subjects. There were no significant differences in the overall distribution of genotypes or alleles for each SNP between EH and NT groups. In the overall distribution of the haplotype-based case-control study constructed based on rs1760944, rs3136817, and rs1130409, the frequency of the G-T-T haplotype was significantly higher in the EH group than in the NT group (2.1% vs. 0.0%, P = 0.001). Multiple logistic regression analysis also revealed significant differences for the G-T-T haplotype, even after adjustment for confounding factors (OR = 8.600, 95% CI: 1.073-68.951, P = 0.043).

CONCLUSIONS

Based on the present results, the G-T-T haplotype appears to be a genetic marker of EH, and the APE1/REF-1 gene appears to be a susceptibility gene for EH.

Resetting process of peripheral circadian gene expression after the combined reversal of feeding schedule and light/dark cycle via a 24-h light period transition in rats

To investigate the effect of light cue on the resetting of the peripheral clocks, we examined the resetting processes of clock genes (Per1, Per2, Bmal1, Cry1, Dec1, and Rev-erbalpha) in the liver and heart of rats after the feeding and light-dark (LD) reversal via a 24-h light period transition. The liver clock was reset quickly within 3 days, while the heart clock needed a longer time course of 5-7 days to be completely re-entrained. Moreover, the re-entrainment of Per1 and Per2 in the liver clock was more rapid than that of the other four clock genes, suggesting the important role of these two clock genes in initiating the circadian resetting of the hepatic clock. However, the resetting rates of these two clock genes were as similar as the others in the heart clock. Therefore, the resetting mechanisms underlining these two peripheral clocks may be totally distinct. Furthermore, the re-entrainment of the liver and heart clocks were relatively lengthened after the feeding and LD reversal via a light period transition compared to a dark period transition, suggesting a simultaneous shift of feeding schedule and the LD cycle may facilitate the circadian resetting in rats.

Visual computing in electron crystallography

VEC is a program package for Visual computing in Electron Crystallography. The program is written mainly in C++ and Fortran and is for running under MS Windows 95, 98, NT and 2000. Apart from its user-friendly interface, sophisticated text-sensitive online helps and tutorials, VEC includes same unique crystallographic methods. They are direct-method image-processing techniques, ab-initio solution of incommensurate crystal structures and algorithms for searching one-dimensionally modulated atoms in 4-dimensional Fourier maps. Examples are given in details.

Haplotype-based case-control study of receptor (calcitonin) activity-modifying protein-1 gene in cerebral infarction

Calcitonin gene-related peptide (CGRP) receptor is a complex molecule that consists of calcitonin receptor-like receptor and receptor activity-modifying protein-1 (RAMP1). It was recently reported that RAMP1-deficient mice (RAMP1(-/-)) showed inflammatory responses with a transiently significant increase in serum CGRP levels and proinflammatory cytokines when compared with RAMP1(+/+) mice. The aim of this study was to investigate the relationship between the human RAMP1 gene and cerebral infarction (CI) using single-nucleotide polymorphisms (SNPs) in a Japanese population. We selected six SNPs in the human RAMP1 gene (rs3754701, rs3769048, rs7557078, rs1584243, rs10199956 and rs7590387) and performed a case-control study using each SNP and haplotype in 171 CI patients and 234 controls. There were no significant differences in overall distribution of genotype and allele frequencies of the SNPs between the CI and control groups. However, there was a significant difference in overall distribution between the CI and control groups (P<0.001) in the haplotype-based case-control study with the combinations of rs3754701-rs3769048-rs7590387. The T-A-C susceptibility haplotype for CI was significantly more frequent than in the control group (P=0.0024). The results suggest that the T-A-C haplotype is a genetic marker for CI, and that RAMP1 or neighbouring genes are associated with increased susceptibility to CI.

Vasorelaxing action of vasonatrin peptide is associated with activation of large-conductance Ca(2+)-activated potassium channels in vascular smooth muscle cells

The aim of this study was to test the hypothesis that vasorelaxing action of vasonatrin peptide (VNP) is due to activation of the large-conductance Ca(2+)-activated potassium channel (BK(Ca)) via guanylyl cyclase (GC)-coupled natriuretic peptide receptors (NPRs) in vascular smooth muscle cells (VSMCs). Contraction experiments were performed using human radial artery, whereas BK(Ca) current by patch clamp was recorded in cells from rat mesenteric artery. Contractility of rings cut from human radial artery was detected in vitro. As a result, VNP induced a dose-dependent vasorelaxation of human radial artery, which could be mimicked by 8-Br-cGMP, and suppressed by TEA, a blocker of BK(Ca), HS-142-1, a blocker of GC-coupled NPRs, or methylene blue (MB), a selective inhibitor of guanylyl cyclase. Sequentially, whole-cell K(+) currents were recorded using patch clamp techniques. BK(Ca) current of VSMCs isolated from rat mesentery artery was obtained by subtracting the whole cell currents after applications of 10(-7) mol/l iberiotoxin (IBX) from before its applications. In accordance with the results of arterial tension detection, BK(Ca) current was significantly magnified by VNP, which could also be mimicked by 8-Br-cGMP, whereas suppressed by HS-142-1, or MB. Taken together, VNP acts as a potent vasodilator, and NPRA/B-cGMP-BK(Ca) is one possible signaling system involved in VNP induced relaxation.

Compare the diagnostic value of FLT and FDG PET/CT in assessment of regional lymph nodes in thoracic esophageal squamous cell carcinoma

e15620

Background: To determine whether FLT PET/CT can detect regional lymph nodes metastases in untreated thoracic esophageal squamous cell carcinoma. In view of the reported high sensitivity of FDG PET/CT for the evaluation of thoracic nodules of esophageal carcinoma, we additionally performed FDG PET/CT for direct comparison with that of FLT. Methods: From March 2008 to December 2008, 18 patients with thoracic esophageal squamous cell carcinoma underwent dual-tracer PET/CT examinations before surgery. The results of reviewing side-by-side FDG PET/CT and FLT PET/CT images for the diagnosis of locoregional lymph node metastases were compared prospectively in relation to pathologic findings. The PET images were visually inspected with the maximum standardized uptake value (SUVmax) determined from a circular region of interest (ROI) over the entire lesion. The differential threshold for malignancy was set as SUVFDG≥2.5, and SUVFLT≥1.4, respectively. Results: All patients underwent esophagectomy and lymphadenectomy, and pathologic examination confirmed nodes positive for metastasis in 14 patients and 42 of 344 excised nodes. The uptake of FDG (median SUVmax, 5.59; range, 2.5–10.6) in locoregional lymph nodes metastasis was significantly higher than that of FLT (median SUVmax, 2.93; range, 1.6–4.6). There were 14 false positive nodes in FDG PET and only 3 in FLT PET, 7 false negative nodes in FDG PET, while 11 false negative nodes in FLT PET. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of FLT PET/CT were 73.81%, 99.01%, 95.93%, 91.18% and 96.45%, respectively, whereas those of FDG PET/CT were 83.33%, 95.36%, 93.90%, 71.43% and 95.36%, respectively. P values were 0.425, 0.014, 0.298, 0.055, and 0.541, respectively. Conclusions: FLT uptake in regional lymph node of esophageal carcinoma is significantly lower compared with FDG uptake.FLT PET has fewer false-positive findings compared with FDG PET. The specificity of FLT PET/CT is higher than that of FDG. We suggest that esophageal carcinoma N-staging need to combine FLT with FDG PET/CT images.

No significant financial relationships to disclose.

Allocation and source attribution of lead and cadmium in maize (Zea mays L.) impacted by smelting emissions

Plants grown in contaminated areas may accumulate trace metals to a toxic level via their roots and/or leaves. In the present study, we investigated the distribution and sources of Pb and Cd in maize plants (Zea mays L.) grown in a typical zinc smelting impacted area of southwestern China. Results showed that the smelting activities caused significantly elevated concentrations of Pb and Cd in the surrounding soils and maize plants. Pb isotope data revealed that the foliar uptake of atmospheric Pb was the dominant pathway for Pb to the leaf and grain tissues of maize, while Pb in the stalk and root tissues was mainly derived from root uptake. The ratio of Pb to Cd concentrations in the plants indicated that Cd had a different behavior from Pb, with most Cd in the maize plants coming from the soil via root uptake.

Heavy metals in an impacted wetland system: a typical case from southwestern China

Historical zinc smelting in Hezhang, southwestern China, has resulted in significant heavy metal contamination of the surrounding ecosystems. The Caohai wetland system, which is an important national nature reserve close to the Hezhang zinc smelting area, was investigated in the present study. Results showed that sediments from the Caohai wetland system have been seriously contaminated by Cd, Pb and Zn with the highest concentrations in the surface sediments being up to 71, 160 and 1,200 microg g(-1), respectively. The heavy metals in the sediments were strongly associated with the organic/sulphide and residual fractions. A more oxidized condition induced by aquatic plants tended to cause the Cd, Pb and Zn bound to the Fe-Mn oxide fraction to become more dominant. Pb isotopic compositions in the sediments indicated that the inventories of Pb in the Caohai wetland sediments were mainly derived from the historical zinc smelting in the Hezhang area, although other anthropogenic sources, such as the gasoline Pb, also made a substantial contribution to the Pb in the sediments. Heavy metal contamination in aquatic plants was also studied and the results indicated that heavy metals accumulated by plants may pose a potential threat to the higher trophic-level organisms, including humans.

The effect of acquisition interval and spatial resolution on dynamic cardiac imaging with a stationary SPECT camera

The current SPECT scanning paradigm that acquires images by slow rotation of multiple detectors in body-contoured orbits around the patient is not suited to the rapid collection of tomographically complete data. During rapid image acquisition, mechanical and patient safety constraints limit the detector orbit to circular paths at increased distances from the patient, resulting in decreased spatial resolution. We consider a novel dynamic rotating slant-hole (DyRoSH) SPECT camera that can collect full tomographic data every 2 s, employing three stationary detectors mounted with slant-hole collimators that rotate at 30 rpm. Because the detectors are stationary, they can be placed much closer to the patient than is possible with conventional SPECT systems. We propose that the decoupling of the detector position from the mechanics of rapid image acquisition offers an additional degree of freedom which can be used to improve accuracy in measured kinetic parameter estimates. With simulations and list-mode reconstructions, we consider the effects of different acquisition intervals on dynamic cardiac imaging, comparing a conventional three detector SPECT system with the proposed DyRoSH SPECT system. Kinetic parameters of a two-compartment model of myocardial perfusion for technetium-99m-teboroxime were estimated. When compared to a conventional SPECT scanner for the same acquisition periods, the proposed DyRoSH system shows equivalent or reduced bias or standard deviation values for the kinetic parameter estimates. The DyRoSH camera with a 2 s acquisition period does not show any improvement compared to a DyRoSH camera with a 10 s acquisition period.

Comparison of gross tumor volume delineated by anatomic imaging and FDG PET/CT for esophageal carcinoma and validation with pathological specimen

15090

Background: Although results of clinical studies have demonstrated FDG PET/CT improved target volume delineation in various tumors, only few studies compared delineation based on PET/CT with pathologic examination. Aim of our study was to compare anatomic imaging modalities including computed tomography (CT), esophagram, endoscopy with FDG PET/CT for delineation of gross tumor volume (GTV) in esophageal carcinoma and to validate the results with the pathologic examination. Methods: Thirty patients with stages II-III squamous cell carcinoma underwent transthoracic esophagectomy were enrolled. PET/CT, esophagram and endoscopy were performed with patients before operations. The length of the lesion on the PET/CT scan and on the CT portion of the PET/CT and the PET scan alone was determined independently by 3 separate investigative groups. PET/CT scan was evaluated by visual inspection for abnormality. A standard uptake value (SUV) of 2.5 was used in the PET scan to delineate the tumor extent. The lengths of GTVs determined with the five modalities (PET/CT, PET, CT, esophagram and endoscopy) were compared quantitatively and validated with the pathologic specimen. The sizes of the tumors were measured by pathologic examination which was considered as the gold standard. Results: Of the 30 patients, 9 had T2 tumors, 20 had T3 tumors and 1 had T4 tumor with an involvement of pleura. Three tumors were located at the upper esophagus, 14 at the middle esophagus, 13 at the lower esophagus. The mean length of the carcinoma was 5.85cm(SD 2.50cm) measured by pathologic examination, 5.79cm (SD 2.04cm) as determined by PET scan, 5.14cm (SD 1.65cm) by PET/CT scan, 5.42 cm(SD 2.42cm)by CT scan, 5.50cm(SD 2.79cm) by endoscopy, and 6.07cm(SD 2.75cm) by esophagram respectively. Although the lengths of the tumors as measured by the five imaging modalities were no significant difference, the result of PET was the most accurate. Conclusions: Compared with tumor lengths measured by pathologic examination, PET with a SUV 2.5 was found to be the most accurate modality and can help the radiation oncologist delineate the GTV of esophageal carcinoma precisely.

No significant financial relationships to disclose.