Comprehensive Metabolomic Analysis Reveals Dynamic Metabolic Reprogramming in Hep3B Cells with Aflatoxin B1 Exposure

Hepatitis B virus (HBV) infection and aflatoxin B1 (AFB1) exposure have been recognized as independent risk factors for the occurrence and development of hepatocellular carcinoma (HCC), but their combined impacts and the potential metabolic mechanisms remain poorly characterized. Here, a comprehensive non-targeted metabolomic study was performed following AFB1 exposed to Hep3B cells at two different doses: 16 μM and 32 μM. The metabolites were identified and quantified by an ultra-performance liquid chromatography-mass spectrometry (UPLC-MS)-based strategy. A total of 2679 metabolites were identified, and 392 differential metabolites were quantified among three groups. Pathway analysis indicated that dynamic metabolic reprogramming was induced by AFB1 and various pathways changed significantly, including purine and pyrimidine metabolism, hexosamine pathway and sialylation, fatty acid synthesis and oxidation, glycerophospholipid metabolism, tricarboxylic acid (TCA) cycle, glycolysis, and amino acid metabolism. To the best of our knowledge, the alteration of purine and pyrimidine metabolism and decrease of hexosamine pathways and sialylation with AFB1 exposure have not been reported. The results indicated that our metabolomic strategy is powerful to investigate the metabolome change of any stimulates due to its high sensitivity, high resolution, rapid separation, and good metabolome coverage. Besides, these findings provide an overview of the metabolic mechanisms of the AFB1 combined with HBV and new insight into the toxicological mechanism of AFB1. Thus, targeting these metabolic pathways may be an approach to prevent carcinogen-induced cancer, and these findings may provide potential drug targets for therapeutic intervention.     

To compare CSF adenosine deaminase levels and CSF-PCR for tuberculous meningitis

This study was planned to compare the adenosine deaminase (ADA) levels and polymerase chain reaction (PCR) in cerebrospinal fluid (CSF) as a rapid method to diagnose tuberculosis meningitis (TBM). Fifty-four adult patients with suspected TBM and 37 controls were included in this study. The median ADA level was 21 U/L of most likely TBM, 14 U/L of unconfirmed TBM and 5 U/L of controls. PCR for Mycobacterium tuberculosis was positive in 12 out of 27 most likely TBM cases, 5 out of 27 unconfirmed TBM cases and 3 out of 37 controls. Using a cut off level of >10 U/L, CSF-ADA had a sensitivity of 92.5% and specificity of 97% for the diagnosis of TBM. PCR for M. tuberculosis had a sensitivity of 44.5% and specificity 92% in the most likely TBM cases. This study shows that CSF-ADA is a more sensitive indicator than PCR for the diagnosis of M. tuberculosis.     

Glutathione-S-transferase A3 knockout mice are sensitive to acute cytotoxic and genotoxic effects of aflatoxin B1

Aflatoxin B1 (AFB1) is a major risk factor for hepatocellular carcinoma (HCC) in humans. However, mice, a major animal model for the study of AFB1 carcinogenesis, are resistant, due to high constitutive expression, in the mouse liver, of glutathione S-transferase A3 subunit (mGSTA3) that is lacking in humans. Our objective was to establish that a mouse model for AFB1 toxicity could be used to study mechanisms of toxicity that are relevant for human disease, i.e., an mGSTA3 knockout (KO) mouse that responds to toxicants such as AFB1 in a manner similar to humans. Exons 3-6 of the mGSTA3 were replaced with a neomycin cassette by homologous recombination. Southern blotting, RT-PCR, Western blotting, and measurement of AFB1-N⁷-DNA adduct formation were used to evaluate the mGSTA3 KO mice. The KO mice have deletion of exons 3-6 of the mGSTA3 gene, as expected, as well as a lack of mGSTA3 expression at the mRNA and protein levels. Three hours after injection of 5 mg/kg AFB1, mGSTA3 KO mice have more than 100-fold more AFB1-N⁷-DNA adducts in their livers than do similarly treated wild-type (WT) mice. In addition, the mGSTA3 KO mice die of massive hepatic necrosis, at AFB1 doses that have minimal toxic effects in WT mice. We conclude that mGSTA3 KO mice are sensitive to the acute cytotoxic and genotoxic effects of AFB1, confirming the crucial role of GSTA3 subunit in protection of normal mice against AFB1 toxicity. We propose the mGSTA3 KO mouse as a useful model with which to study the interplay of risk factors leading to HCC development in humans, as well as for testing of additional possible functions of mGSTA3.     

A 36-year-old man with AIDS and relapsing, nonproductive cough

A rapidly progressive, fatal recrudescence of pulmonary Kaposi sarcoma developed in an HIV-infected man who was receiving corticosteroids for treatment of an immune reconstitution syndrome secondary to Mycobacterium avium complex pulmonary infection. We discuss the implications for current diagnosis and management of HIV-associated pulmonary diseases.     

Evaluation of clinico-radiological, bacteriological, serological, molecular and histological diagnosis of osteoarticular tuberculosis

Background:

The diagnosis of osteoarticular tuberculosis is clinico-radiological in endemic areas. However every patient does not have the classical picture. Osteoarticular tuberculosis is a paucibacillary disease hence bacteriological diagnosis is possible in 10-30% of the cases. The present study is undertaken to correlate clinico-radiological, bacteriological, serological, molecular and histological diagnosis.

Materials and Methods:

Fifty clinico-radiologically diagnosed patients of osteoarticular tuberculosis with involvement of dorsal spine (n = 35), knee (n = 8), shoulder (n = 1), elbow (n = 2) and lumbar spine lesion (n = 4), were analyzed. Tissue was obtained after decompression in 35 cases of dorsal spine and fine needle aspiration in the remaining 15 cases. Tissue obtained was subjected to AFB staining, AFB culture sensitivity, aerobic/anaerobic culture sensitivity histopathological examination and polymerase chain reaction (PCR) using 16srRNA as primer. Serology was performed by ELISA in 27 cases of dorsal spine at admission and one and three months postoperatively.

Results:

AFB staining (direct) and AFB culture sensitivity was positive in six (12%) cases. Aerobic/anaerobic culture sensitivity was negative in all cases. Histology was positive for TB in all the cases. The PCR was positive in 49 (98%) cases. All dorsal spine tuberculosis cases showed fall of IgM titer and rise of IgG titer at three months as compared to values at admission.

Conclusion:

Histopathology and PCR was diagnostic in all cases of osteoarticular tuberculosis. The serology alone is not diagnostic.     

ELISA法测定部分种子和果实类中药黄曲霉毒素B1含量

目的 间接竞争酶联免疫吸附法(ELISA)法测定部分种子果实类黄曲霉毒素B1的含量.方法 间接竞争酶联免疫吸附法(ELISA法).结果 样品均有不同程度的污染黄曲霉毒素B1(AFB1),并且在贮藏过程中有发霉现象者含量较高.结论 建立黄曲霉毒素B1含量限度标准非常必要.     

广西肝癌中HBV感染与N_ras基因突变的研究

AIM To observe the roles of N-ras gene mutation and hepatitis B virus (HBV) infection in the carcinogenesis of hepatocellular carcinoma (HCC) in Guangxi, China.METHODS The polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and immunohistochemistry were used to detect N-ras gene mutation and HBV infection in 29 cases of HCC.RESULTS The aberration rates at codon 2-37 of N-ras were 79.31% in HCCs and 80.77% in adjacent non-tumorous liver tissues. More than 2 point mutations of N-ras gene were observed in 22 (75.86%) cases. HBsAg and HBxAg positive rates were 86.2% and 79.3%. There was a parallel tendency between HBV marker detections and the mutation rate of N-ras gene.CONCLUSION HBV infection and N-ras gene mutation may be involved in the carcinogenesis and development of HCC in Guangxi. Since the aflatoxin B1 contamination is one of risk factors for HCC in this area, it may contribute to the mutation of N-ras gene in carcinogenesis of HCC.INTRODUCTIONHepatocellular carcinoma (HCC) is one of common malignant tumors in People′s Republic of China. Guangxi is a high incidence area of HCC. Many factors are involved in hepatocarcinogenesis. Many studies revealed that hepatitis B virus (HBV) infection might be a risk factor for hepatocellular carcinogenesis. One theory for hepatocarcinogenesis is that the oncogene(s) may be transactivated by hepatitis B x antigen (HBxAg)[1]. It is found recently that activation of N-ras gene may be the molecular basis for the carcinogenesis and development of HCC[2,3]. There have been reports about overexpression of N-ras oncogene in human HCC[4], but a few dealt with the roles of N-ras gene mutation and HBV infection, and their relationship with HCC. We analyzed the N-ras gene mutation and HBV infection in HCC by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and immunohistochemistry in 29 cases of human HCC.     

A case of Mycobacterium tuberculosis laboratory cross-contamination

SettingA laboratory cross-contamination event was suspected because Mycobacterium tuberculosis was unexpectedly detected at a high incidence in the cultures of several clinical specimens at the National Hospital Organization, Tokyo National Hospital, Japan.ObjectiveTo describe a case of Mycobacterium tuberculosis laboratory cross-contamination.DesignWe reviewed the medical records of 20 patients whose clinical specimens were suspected to have been contaminated by Mycobacterium tuberculosis. Variable number of tandem repeat analysis with 15 loci, the Japan Anti-Tuberculosis Association-12, and three additional hyper-variable loci, was performed to identify the cross-contamination event.ResultsThe clinical, laboratory, and variable number of tandem repeat data revealed that the cross-contamination had possibly originated from one strongly positive specimen, resulting in false-positive results in 11 other specimens, including a case treated with anti-tuberculosis drugs.ConclusionClinical and laboratory data must be re-evaluated when cross-contamination is suspected and variable number of tandem repeat analysis should be used to confirm cross-contamination. Furthermore, original isolates should be stored appropriately, without sub-culturing and genotyping should be performed at the earliest possible for better utilization of variable number of tandem repeat for the identification of cross-contamination.     

Clinical correlates of coronary cineangiography in young males with myocardial infarction.

Thirty-eight men who suffered acute transmural myocardial infarction before age 40, and after recovery were New York Heart Association functional Class I or II, were studied by noninvasive means and by coronary angiography in order to determine whether these nonivasive studies could predict the presence of significant coronary artery disease remote from that felt to be responsible for the previous myocardial infarction. Patients were divided into two groups on the basis of the absence (Group I) or presence (Group II) of obstructive disease in a major coronary artery supplying myocardium remote from the prior myocardial infarction. There were 21 patients in Group I and 17 patients in Group II. They did not differ with respect to age, abnormalities of lipid or glucose metabolism, family history, history of hypertension or cigarette use, presence of obesity, or infarct localization. Ten of 17 patients in Group II had angina pectoris; only 3/21 patients in Group I had angina pectoris (p less than 0.01). All 12 patients tested in Group II had a positive maximal exercise tolerance test; only 1/17 patients tested in Group I was similarly positive (p less than 0.001). The absence of angina pectoris and the presence of a negative maximal exercise tolerance test is strong evidence against the pressure of significant CAD remote from that responsible for the prior myocardial infarction.     

Aflatoxin B1 and M1 contamination in cow feeds and milk from Iran

In this study, 288 milk samples were collected randomly from individual farms in Qazvin province from March to February 2012, Iran. Samples were analysed for Aflatoxin M1 (AFM1) by ELISA; also the Aflatoxin B1 (AFB1) contamination in animal feed was determined at the same time as the sampling of raw milk. One hundred and sixty-three samples (56.59%) were found to contain AFM1 at various levels; the presence of AFM1 was detected in a concentration ranging between 0.01 and 0.22 ppb. In 113 (69.32%) of the 163 milk samples, AFM1 levels were found to be higher than the maximum tolerable limit (0.05 ppb) accepted by the European union/Codex Alimentarius Commission. The mean AFM1 contamination levels in milk in summer and winter were 0.08 and 0.18 ppb, respectively. The AFB1 contamination level in the winter feed (2.27 ± 1.76) was higher than from summer (0.83 ± 0.60) (P < 0.05).