Association between genetic variants in VEGF, ERCC3 and occupational benzene haematotoxicity

INTRODUCTION

Benzene is an established human haematotoxin, with substantial interindividual variation in benzene-induced toxicity.

METHODS

To further examine if genetic variation contributes to benzene haematotoxicity, we analysed 1023 tagSNPs in 121 gene regions important for benzene metabolism, haematopoiesis, leukaemia and lymphoma among 250 workers exposed to benzene and 140 unexposed controls in a cross-sectional study carried out in China. Linear regression was used to analyse the relationship between genetic polymorphisms and total white blood cell (WBC) count and its subtypes, adjusting for potential confounders and occupational exposure to benzene and toluene among exposed workers. The minp test assessed the association on the gene region level. The false discovery rate method was used to control for multiple comparisons.

RESULTS

VEGF (minp = 0.0030) and ERCC3 (minp = 0.0042) were the most significantly associated gene regions with altered WBC counts among benzene-exposed workers, after accounting for multiple comparisons. Highly significant changes were also found for WBC subtype counts, including granulocytes, CD4+ T cells and lymphocytes for VEGF and granulocytes and NK cells for ERCC3. Further, in workers exposed to <1 ppm, a SNP in VEGF was associated with changes in WBC and granulocyte counts, and SNPs in ERCC3 were associated with changes in WBC, NK cell and granulocyte counts.

DISCUSSION

Our findings suggest that genetic variation in VEGF, which plays an important role in blood vessel growth, and ERCC3, which is a member of the DNA repair pathway and is responsible for repairing bulky DNA adducts formed by chemicals, may contribute to individual susceptibility to benzene-induced haematotoxicity at relatively low levels of benzene exposure.

Polymorphisms in the interleukin 3 gene show strong association with susceptibility to Graves' disease in Chinese population

Graves' disease (GD) is a common organ-specific autoimmune disorder, which is multifactorial and develops in genetically susceptible individuals. We had earlier mapped a susceptibility locus for GD to chromosome 5q31-33 in a linkage study. Here we used tag single-nucleotide polymorphisms (SNPs) to search for genetic variants associated with GD, and examined 19 functional candidate genes in this chromosomal region. We identified 192 polymorphisms by re-sequencing the candidate genes, and selected 51 tagSNPs to genotype in a case-control collection of 1118 south Han Chinese subjects (428 cases and 690 controls). Initial analysis suggested that a non-synonymous SNP rs40401 (P27S) of interleukin 3 (IL3) was associated with GD, and further fine-mapping showed that rs40401, or its perfect proxy SNP rs31480 in the 5' flanking region of IL3, fully accounted for the association signal at this locus. We replicated significant association of rs40401 with GD in an independent sample collection of 839 north Han Chinese subjects. A combined analysis revealed strong validation of this association (odds ratio (OR(common))=1.63, combined P (P(comb))=4 x 10(-6) in the Recessive disease model). This study provides convincing evidence that the IL3 gene is a susceptibility locus for GD in the Chinese population.

Portable stove use is associated with lower lung cancer mortality risk in lifetime smoky coal users

Domestic fuel combustion from cooking and heating, to which about 3 billion people worldwide are exposed, is associated with increased lung cancer risk. Lung cancer incidence in Xuanwei is the highest in China, and the attributable risk of lung cancer from unvented smoky coal burning is greater than 90%. To evaluate any lung cancer mortality reduction after changing from unvented stoves to portable stoves, we used lifetime smoky coal users in a retrospective cohort of all farmers born during 1917–1951 and residing in Xuanwei in 1976. Of the 42 422 enrolled farmers, 4054 lifetime smoky coal users changed to portable stoves, 4364 did not change, and 1074 died of lung cancer. Lung cancer morality associated with stove change was assessed by product-limit survival curves and multivariate Cox regression models. Both men (P<0.0001) and women (P<0.0001) who changed to portable stoves had a significantly increased probability of survival compared with those who did not change. Portable stoves were associated with decreased risk of lung cancer mortality in male participants (hazard ratio (HR)=0.62, 95% confidence interval (CI)=0.46–0.82) and female participants (HR=0.41, 95% CI=0.29–0.57). Portable stove use is associated with reduced lung cancer mortality risk, highlighting a cost-effective intervention that could substantially benefit health in developing countries.

Statins decrease the aberrant HLA-DR expression on thyrocytes from patients with Hashimoto's thyroiditis

Statins have been found to exert anti-inflammatory and immune modulatory effects. It seems likely that these drugs may improve thyroid function in patients with Hashimoto's thyroiditis (HT). The objective of our study was to investigate the effect of statins on HLA-DR (human leukocyte antigen D-related) expression of thyrocytes from patients with HT hypothyroidism. Thyroid tissues were obtained from surgical specimens. Thyrocytes were cultured in the presence or absence of IFN-gamma (50 ng/ml) with or without statins (simvastatin 10 microM or atorvastatin 10 microM) for 72 hours. HLA-DR expression was detected by flow cytometry. Normal thyrocytes were used for controls. HLA-DR expression of HT thyrocytes was much higher than that of normal thyrocytes (41.2+/-4.5% vs. 2.7+/-2.1%, p<0.01), which could be further increased by IFN-gamma stimulation in both groups (p<0.01). However, simvastatin and atorvastatin could significantly inhibit the "aberrant" HLA-DR expression on HT thyrocytes and decrease IFN-gamma- induced HLA-DR expression in both HT and normal thyroid cells (p<0.01). Statins can repress HLA-DR expression of HT thyrocytes, which might inhibit the subsequent lymphocyte activation and ameliorate the immune disturbance of HT.

Mismatch negativity in paranoid, schizotypal, and antisocial personality disorders

AIMS

The mismatch negativity (MMN) to frequency deviant tones has yielded conflicting results in patients with schizophrenia. This might be because Axis I schizophrenia overlaps with Axis II diagnoses such as paranoid or schizotypal personality disorders. This study was designed to address this issue.

METHODS

We evaluated the auditory MMN to frequency deviance in 17 patients with paranoid, 15 schizotypal, and 16 antisocial personality disorders. These were compared to 25 healthy subjects.

RESULTS

N1 to both deviant and standard tones was shorter in the paranoid group when compared to healthy controls. MMN latencies were shorter at Fz, Cz, and Pz in the paranoid group when compared to healthy controls, schizotypal, and antisocial groups. MMN amplitudes were higher at Fz and Cz in the schizotypal and antisocial groups when compared to healthy controls and the paranoid group.

CONCLUSIONS

Patients with paranoid personality disorder had faster automatic detection of auditory stimuli and of their change, but normal inhibition of irrelevant stimuli. By contrast, patients with schizotypal and antisocial personality disorders had normal discrimination of the auditory stimuli, but might have a deficit in inhibition on irrelevant stimuli. Our results might help differentiate these personality types, and clarify some MMN findings in schizophrenia.

Instantaneous frequency estimate of nonstationary phonocardiograph signals using hilbert spectrum

A method for analyzing the nonlinear and non-stationary processes and investigating the instantaneous frequency of the practical medical signals is presented. The aim of this contribution is to explore the role that both empirical mode decomposition and Hilbert transform can be applied to play in phonocardiograph (PCG) signals. Hilbert transform is used to each intrinsic mode function to obtain the global time-frequency distribution of the underlying signal with a point of view of instantaneous frequency. Two kinds of clinical phonocardiograph signals with normal and abnormal cardiac functions were analyzed by using the proposed approach. The instantaneous frequency distributions of the PCG signals were also compared with the results by using the Morlet wavelet transform. Both simulation and experimental results were presented and discussed to demonstrate the power and effectiveness of the proposed approach.

Living environment and schooling of children with HIV-infected parents in southwest China

A cross-sectional household survey was conducted in Longchuan County, China, to study the lives of children with HIV-infected parents. Registered HIV-infected drug users and their households were approached and information about the living environment of children < or =15 years of age was collected. Of the 266 households interviewed, there were 213 children < or =15 years old. Forty percent of the children had lost at least one parent. Most of the children resided in a household with low economic status and a high dependency ratio. One-half of the children experienced discordant family relations, family anxiety and shame. Compared to orphans, non-orphans and their families were less likely to receive social support from the community. Orphans and older children were less likely to attend school and more likely to be truant if enrolled in school. Findings in the current study suggest that many children whose parents are infected with HIV or have died from HIV are living in stressful environments with minimal support from the community. Efforts should be taken to provide support and supervision to these children.

Influence of the Plasmodium falciparum P-glycoprotein homologue 1 (pfmdr1 gene product) on the antimalarial action of cyclosporin

BACKGROUND AND OBJECTIVES

The immunosuppressant cyclosporin A and a number of other cyclosporins have potent and selective antimalarial activity. Their exact mechanism of antimalarial action is unknown but the structure-activity relationships for malarial parasite inhibition and immunosuppression differ markedly. The 3'-keto derivative of cyclosporin D (valspodar) is particularly potent against the human malarial parasite Plasmodium falciparum in culture but causes negligible immunosuppression. Multidrug resistance in mammalian cancer cells, the result of overproduction of the P-glycoprotein, can be reversed by certain cyclosporins, particularly valspodar. We therefore investigated the possibility that the antimalarial target of cyclosporin might be a P-glycoprotein homologue. P. falciparum P-glycoprotein homologue 1 (Pgh1; the pfmdr1 gene product) is located in the digestive vacuole (DV) membrane of the parasite. Its function is unknown but it modulates the susceptibility of parasites to quinolines and related antimalarial drugs, including quinine, mefloquine, halofantrine and chloroquine, and to artemisinin.

METHODS AND RESULTS

Here we demonstrate that (i) sequence polymorphisms in pfmdr1 altered the susceptibility of parasites to cyclosporin A and (ii) pfmdr1-overexpressing strains were slightly less susceptible to the drug. Furthermore, we found synergistic antimalarial interactions between cyclosporin A and quinine, mefloquine or halofantrine and antagonism between cyclosporin A and chloroquine. However, we were unable to detect a direct interaction between cyclosporin and Pgh1.

CONCLUSIONS

The amino acid sequence and copy number of Pgh1 may influence cyclosporin susceptibility as a result of a direct interaction between the drug and the protein, or via indirect effects on the physiology of the DV.

B7-H1 expression is upregulated in peripheral blood CD14+ monocytes of patients with chronic hepatitis B virus infection, which correlates with higher serum IL-10 levels

Chronicity in hepatitis B virus (HBV) infection is maintained by increased type 2 T-helper cell response, possibly because of increased interleukin-10 (IL-10) productions. B7-H1 can negatively regulate T-cell responses via its receptor, programmed death 1. Ligation of B7-H1 to T-cells can result in the preferential secretion of IL-10. In this study, we investigated whether there was an upregulated expression of B7-H1 in peripheral blood mononuclear cells in patients chronically infected by HBV and further explored the correlation between B7-H1 expression and serum interleukin 2, interferon-gamma, IL-10, HBeAg, alanine aminotransferase (ALT) levels and viral load. Fifty-five patients with chronic HBV infection and 20 healthy controls (HCs) were enrolled in the present study. The results showed that in patients with chronic hepatitis B CD14+ monocytes but not CD3+ and CD19+ cells had a significantly increased expression of B7-H1 compared with HCs, which positively correlates with serum IL-10 levels and the presence of HBeAg and negatively correlates with serum ALT levels. In conclusion, chronic HBV patients harbour an increased B7-H1 expression in CD14+ monocytes compared with controls, which may be responsible for the increased serum IL-10 levels. This might be an important way by which HBV evades an adequate immune response, leading to viral persistence and disease chronicity.