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1.
Eur J Clin Microbiol Infect Dis ; 39(4): 749-751, 2020 Apr.
Article in English | MEDLINE | ID: mdl-31858355

ABSTRACT

Community-acquired pneumonia (CAP) is one of the major causes of morbidity, mortality and hospitalization, and S. pneumoniae is the most frequently isolated etiologic agent. The pneumococcal urinary antigen test (PUAT) is among the recommended methods to identify the causative agent in CAP patients. A novel PUAT (IMMUNOCATCHTMStreptococcus pneumoniae) was compared with the Uni-GoldTMS. pneumoniae assay routinely used in our laboratory and with the widely used BinaxNOW® S. pneumoniae antigen card. A total of 218 (183 freshly harvested and 35 frozen) urine samples (US) submitted for the detection of pneumococcal urinary antigen (PUAT) between December 2016 and November 2018 were evaluated. A number of 160 negative and 41 positive concordant results were scored for all the three assays. A total of 17 US gave discrepant results. The sensitivity and specificity of Immunocatch compared with Uni-Gold were 73.2% and 98.8%, respectively, and compared with BinaxNOW were 97.6% and 98.8%, respectively. The overall percent agreement (OPA) and the Cohen's kappa coefficient between the Immunocatch and the Uni-Gold resulted 92.2% and 0.78%, respectively, and compared with BinaxNOW were 98.6% and 0.95%, respectively. These performances suggest that the novel Immunocatch S. pneumoniae test is a useful tool for qualitative detection of S. pneumoniae capsular antigen in US.


Subject(s)
Antigens, Bacterial/urine , Clinical Laboratory Techniques/standards , Pneumonia, Pneumococcal/diagnosis , Pneumonia, Pneumococcal/urine , Reagent Kits, Diagnostic/standards , Clinical Laboratory Techniques/methods , Community-Acquired Infections/diagnosis , Community-Acquired Infections/microbiology , Community-Acquired Infections/urine , Humans , Sensitivity and Specificity , Streptococcus pneumoniae
2.
J Clin Microbiol ; 57(8)2019 08.
Article in English | MEDLINE | ID: mdl-31092595

ABSTRACT

Legionnaires' disease (LD) refers to a serious form of acute pneumonia caused by Legionella species. LD can be difficult to diagnose because the signs and symptoms are nonspecific, and therefore a rapid laboratory diagnosis is of paramount importance. In this study, a recently introduced immunochromatographic test (Immunocatch Legionella; Eiken Chemical Co., Ltd.) for Legionella pneumophila (serogroup 1) urinary antigen detection was compared with the Sofia Legionella fluorescent immunoassay (FIA) (Quidel) (routinely used in our laboratory) and with the widely used BinaxNOW Legionella assay (Alere). A total of 248 urine samples (60 frozen and 188 fresh) were evaluated. All of the samples were collected from patients with high clinical suspicion of Legionnaires' disease. The three assays were performed simultaneously according to the manufacturers' instructions. A total of 180 concordant negative and 66 concordant positive results were obtained. Only 2 discrepant results were registered. The sensitivity and specificity of Immunocatch compared with Sofia were, respectively, 98.5% and 99.4%. Cohen's kappa coefficient and overall percent agreement between Immunocatch and Sofia were also calculated and resulted in, respectively, 0.97 and 99.2%. These performances suggest that the Immunocatch test is a useful tool for Legionella pneumophila (serogroup 1) urinary antigen detection.


Subject(s)
Antigens, Bacterial/urine , Fluorescent Antibody Technique , Immunoassay/standards , Legionnaires' Disease/diagnosis , Legionnaires' Disease/urine , Antigens, Bacterial/immunology , Community-Acquired Infections/diagnosis , Community-Acquired Infections/microbiology , Community-Acquired Infections/urine , Humans , Immunoassay/methods , Legionella pneumophila/immunology , Sensitivity and Specificity , Serogroup
3.
Eur J Clin Microbiol Infect Dis ; 37(11): 2107-2115, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30094522

ABSTRACT

Intra-abdominal infections (IAIs) are one of the most common type of infections in patients with sepsis and an important cause of death in intensive care units. Early detection and treatment are necessary to reduce patient complications and improve outcomes. The Unyvero IAI Application (Curetis GmbH) is the first automated assay to rapidly and simultaneously identify a large panel of bacteria, fungi, toxins, and antibiotic resistance markers directly from IAI-related samples. The assay was evaluated in four European clinical laboratories in comparison to routine microbiological practices. A total of 300 clinical samples were tested with an overall sensitivity of 89.3% and specificity of 99.5%, while time to results was reduced by an average of about 17 h compared to identification (ID) results and 41 h compared to full antibiotic susceptibility testing (AST) results. The Unyvero IAI was able to detect additional microorganisms compared with culture, in particular anaerobes, with most detections confirmed by sequencing. The most frequent resistance markers detected were mecA/mecC (n = 25), aacA4 (n = 20), and blaCTX-M (n = 17) and carbapenemase genes were identified in nine specimens. Further studies are now required to determine the clinical impact of this new rapid test which could play a role in the successful treatment of IAI.


Subject(s)
Intraabdominal Infections/diagnosis , Intraabdominal Infections/microbiology , Microbiological Techniques , Molecular Diagnostic Techniques , Bacteria/drug effects , Bacteria/genetics , Bacterial Toxins/genetics , Diagnostic Tests, Routine , Drug Resistance, Microbial , Humans , Reproducibility of Results , Sensitivity and Specificity
4.
Int J Infect Dis ; 69: 96-98, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29447913

ABSTRACT

OBJECTIVES: To start a surveillance program to investigate the possible diffusion of mobilized colistin resistance genes in Enterobacteriaceae strains isolated in the Unit of Microbiology of the Great Romagna Hub Laboratory. METHODS: All the colistin resistant Enterobacteriaceae, isolated from August 1st 2016 to July 31st 2017, were prospectively evaluated for mcr-1 and mcr-2. Backdated survey of mcr-3, mcr-4 and mcr-5 was performed on the same group of isolates. Species identification was achieved by Vitek MS and the antibiotic susceptibility testing was performed both with Vitek-2 and Sensititre systems. Colistin resistant isolates were screened by PCR for the presence of the plasmid-mediated colistin resistance genes and amplicons were verified by sequencing. All mcr-1 positive isolates were subjected to MLST analysis. RESULTS: Over the total of 19053 isolates belonging to Enterobacteriaceae, 90 were colistin resistant. The presence of mcr-1 was detected in 26 Escherichia coli. The overall prevalence of mcr-1 was 0.14%. The mcr-1 positive E. coli strains were assigned to 13 distinct sequence types (STs) according to MLST. CONCLUSIONS: The prospective epidemiological survey carried out in our study gave a glimpse of the plasmid-mediated colistin resistance dissemination in Romagna. Since the prevalence rate of carbapenem resistant Enterobacteriaceae (CRE) in some hospital wards in our area is alarming, we underline the importance of a Surveillance Program to monitor the spread of the plasmid-mediated colistin resistance genes into MDR Gram-negative bacteria.


Subject(s)
Anti-Bacterial Agents/pharmacology , Colistin/pharmacology , Drug Resistance, Multiple, Bacterial , Enterobacteriaceae/drug effects , Enterobacteriaceae/genetics , Escherichia coli Proteins/genetics , Carbapenems/pharmacology , Eggs/microbiology , Enterobacteriaceae Infections/drug therapy , Escherichia coli Proteins/metabolism , Food Contamination , Food Microbiology , Foodborne Diseases/drug therapy , Foodborne Diseases/microbiology , Humans , Italy , Meat/microbiology , Plasmids/genetics , Plasmids/metabolism , Risk Factors
5.
Oncogene ; 36(1): 122-132, 2017 01 05.
Article in English | MEDLINE | ID: mdl-27292261

ABSTRACT

The availability of bromodomain and extra-terminal inhibitors (BETi) has enabled translational epigenetic studies in cancer. BET proteins regulate transcription by selectively recognizing acetylated lysine residues on chromatin. BETi compete with this process leading to both downregulation and upregulation of gene expression. Hypoxia enables progression of triple negative breast cancer (TNBC), the most aggressive form of breast cancer, partly by driving metabolic adaptation, angiogenesis and metastasis through upregulation of hypoxia-regulated genes (for example, carbonic anhydrase 9 (CA9) and vascular endothelial growth factor A (VEGF-A). Responses to hypoxia can be mediated epigenetically, thus we investigated whether BETi JQ1 could impair the TNBC response induced by hypoxia and exert anti-tumour effects. JQ1 significantly modulated 44% of hypoxia-induced genes, of which two-thirds were downregulated including CA9 and VEGF-A. JQ1 prevented HIF binding to the hypoxia response element in CA9 promoter, but did not alter HIF expression or activity, suggesting some HIF targets are BET-dependent. JQ1 reduced TNBC growth in vitro and in vivo and inhibited xenograft vascularization. These findings identify that BETi dually targets angiogenesis and the hypoxic response, an effective combination at reducing tumour growth in preclinical studies.


Subject(s)
Azepines/pharmacology , Carbonic Anhydrase IX/metabolism , Hypoxia/metabolism , Neovascularization, Pathologic , Triazoles/pharmacology , Triple Negative Breast Neoplasms/metabolism , Triple Negative Breast Neoplasms/pathology , Animals , Carbonic Anhydrase IX/genetics , Cell Line, Tumor , Cluster Analysis , Disease Models, Animal , Female , Gene Expression Profiling , High-Throughput Nucleotide Sequencing , Humans , Hypoxia/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Mice , Promoter Regions, Genetic , Protein Binding , Spheroids, Cellular , Transcriptome , Triple Negative Breast Neoplasms/genetics , Tumor Cells, Cultured , Vascular Endothelial Growth Factor A , Xenograft Model Antitumor Assays
6.
J Viral Hepat ; 24(6): 454-463, 2017 06.
Article in English | MEDLINE | ID: mdl-27976461

ABSTRACT

The availability of direct-acting antiviral agents (DAA) regimens has expanded the pool of patients eligible for treatment. However, data on the virologic response and tolerability of DAAs in elderly patients are lacking. We evaluated the efficacy and safety of DAAs in patients with advanced fibrosis/cirrhosis in real-life practice with the focus on those aged ≥65 years. Between January and December 2015, all consecutive patients with HCV-related advanced fibrosis/cirrhosis treated with DAA at eleven tertiary referral centres in Emilia Romagna (Italy) were enrolled. Regimen choice was based on viral genotype and stage of disease, according to guidelines. The primary end point was sustained virologic response 12 weeks after the end of treatment (SVR12). Overall, 282 of 556 (50.7%) patients evaluated were elderly, most of them with cirrhosis. Antiviral therapy was stopped prematurely in four (1.4%) patients. Two patients, both with cirrhosis, died during treatment due to worsening of liver/renal function. SVR12 was achieved by 94.7% and was comparable to that obtained in patients aged <65 (P=.074). Similar data were also reported in subgroup of patients aged ≥75 years. All patients with advanced fibrosis achieved virologic response. SVR12 was 80.8% in Child-Pugh-Turcotte (CTP)-B cirrhosis and 95.4% in CTP-A (P=.013). According to genotype, the SVR12 was achieved in 172 of 181 (95%) with genotype 1b cirrhosis and in 44 of 48 (91.7%) with genotype 2 cirrhosis. In conclusions, in a real-world setting, DAAs are safe and effective in elderly patients with HCV-related advanced fibrosis/cirrhosis, but SVR12 is lower with worsening CTP class.


Subject(s)
Antiviral Agents/adverse effects , Antiviral Agents/therapeutic use , Hepatitis C, Chronic/drug therapy , Adult , Aged , Aged, 80 and over , Genotype , Hepacivirus/classification , Hepacivirus/genetics , Hepacivirus/isolation & purification , Hepatitis C, Chronic/virology , Humans , Italy , Middle Aged , Retrospective Studies , Sustained Virologic Response , Tertiary Care Centers , Treatment Outcome , Young Adult
7.
Oncogene ; 34(34): 4546, 2015 Aug 20.
Article in English | MEDLINE | ID: mdl-26289678

ABSTRACT

Correction to: Oncogene (2015) 34, 4482­4490; doi:10.1038/onc.2014.378; published online 24 November 2014. Following the online publication of this article, the authors have noticed a misspelt surname: S Hider should read S Haider. There is also an addition to the acknowledgements to read 'This study makes use of data generated by the Molecular Taxonomy of Breast Cancer International Consortium, which was funded by Cancer Research UK and the British Columbia Cancer Agency Branch'. The corrected article appears in this issue. The authors would like to apologise for any inconvenience this may cause.

8.
Oncogene ; 34(34): 4482-90, 2015 Aug 20.
Article in English | MEDLINE | ID: mdl-25417700

ABSTRACT

Activation of cellular transcriptional responses, mediated by hypoxia-inducible factor (HIF), is common in many types of cancer, and generally confers a poor prognosis. Known to induce many hundreds of protein-coding genes, HIF has also recently been shown to be a key regulator of the non-coding transcriptional response. Here, we show that NEAT1 long non-coding RNA (lncRNA) is a direct transcriptional target of HIF in many breast cancer cell lines and in solid tumors. Unlike previously described lncRNAs, NEAT1 is regulated principally by HIF-2 rather than by HIF-1. NEAT1 is a nuclear lncRNA that is an essential structural component of paraspeckles and the hypoxic induction of NEAT1 induces paraspeckle formation in a manner that is dependent upon both NEAT1 and on HIF-2. Paraspeckles are multifunction nuclear structures that sequester transcriptionally active proteins as well as RNA transcripts that have been subjected to adenosine-to-inosine (A-to-I) editing. We show that the nuclear retention of one such transcript, F11R (also known as junctional adhesion molecule 1, JAM1), in hypoxia is dependent upon the hypoxic increase in NEAT1, thereby conferring a novel mechanism of HIF-dependent gene regulation. Induction of NEAT1 in hypoxia also leads to accelerated cellular proliferation, improved clonogenic survival and reduced apoptosis, all of which are hallmarks of increased tumorigenesis. Furthermore, in patients with breast cancer, high tumor NEAT1 expression correlates with poor survival. Taken together, these results indicate a new role for HIF transcriptional pathways in the regulation of nuclear structure and that this contributes to the pro-tumorigenic hypoxia-phenotype in breast cancer.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/physiology , Breast Neoplasms/pathology , Cell Hypoxia , RNA, Long Noncoding/physiology , Transcriptional Activation , Animals , Apoptosis , Breast Neoplasms/metabolism , Cell Adhesion Molecules/genetics , Cell Proliferation , Cell Survival , Female , Humans , Mice , Receptors, Cell Surface/genetics
9.
Expert Opin Investig Drugs ; 21(4): 437-49, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22324304

ABSTRACT

INTRODUCTION: Current therapies for recurrent ovarian cancer (OC) yield relatively modest improvements in survival. Many drugs are available but recently a renewed interest is addressed on antimetabolite drugs. Pemetrexed (PEM) is a multitargeted antifolate cytotoxic agent mainly used in lung cancer. AREAS COVERED: This review summarizes the available evidence on the use of PEM in the treatment of OC. This article consists of material obtained via Medline, PubMed and EMBASE literature searches, up to November 2011. Currently available published data on mechanism of action, pharmacokinetics, safety and efficacy of PEM in the treatment of recurrent OC are described. EXPERT OPINION: Eight trials evaluated the use of PEM in OC patients. Studies using PEM in combination with carboplatin in platinum-sensitive OC suggested that the response rate is similar to other combination therapies. However, based on the absence of randomized trials comparing this doublet with currently used combination treatments, it is difficult to draw conclusions on the efficacy of PEM regimens in these patients. In platinum-resistant OC patients, two studies suggested that PEM alone might have equivalent activity to other single-agent treatment. Further pharmacogenomic and clinical data are warranted to better define the role of PEM in the treatment of recurrent OC.


Subject(s)
Antimetabolites, Antineoplastic/therapeutic use , Glutamates/therapeutic use , Guanine/analogs & derivatives , Ovarian Neoplasms/drug therapy , Clinical Trials as Topic , Female , Guanine/therapeutic use , Humans , Pemetrexed , Randomized Controlled Trials as Topic
10.
Ultrasound Obstet Gynecol ; 37(5): 603-13, 2011 May.
Article in English | MEDLINE | ID: mdl-21351180

ABSTRACT

OBJECTIVES: To compare the accuracy of multidetector computerized tomography enteroclysis (MDCT-e) and rectal water contrast transvaginal ultrasonography (RWC-TVS) in determining the presence and extent of bowel endometriosis. METHODS: This prospective study included 96 patients of reproductive age with suspicion of bowel endometriosis. Patients underwent MDCT-e and RWC-TVS before operative laparoscopy. Findings of MDCT-e and RWC-TVS were compared with histological results. The severity of pain experienced during MDCT-e and RWC-TVS was measured by a 10-cm visual analog scale. RESULTS: Fifty-one patients had bowel endometriotic nodules at surgery. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy for the diagnosis of rectosigmoid endometriosis were 95.8% (46/48), 100.0% (48/48), 100.0% (46/46), 96.0% (48/50) and 97.9% (94/96) for MDCT-e and 93.8% (45/48), 97.9% (47/48), 97.8% (45/46), 94.0% (47/50) and 95.8% (92/96) for RWC-TVS. MDCT-e was associated with more intense pain than was RWC-TVS. CONCLUSIONS: MDCT-e and RWC-TVS have similar accuracy in the diagnosis of rectosigmoid endometriosis, but patients tolerate RWC-TVS better than they do MDCT-e.


Subject(s)
Endometriosis/diagnostic imaging , Inflammatory Bowel Diseases/diagnostic imaging , Administration, Rectal , Adult , Female , Humans , Laparoscopy/methods , Prospective Studies , Sensitivity and Specificity , Tomography, X-Ray Computed , Ultrasonography , Water
11.
Minerva Ginecol ; 62(3): 179-85, 2010 Jun.
Article in English, Italian | MEDLINE | ID: mdl-20595942

ABSTRACT

AIM: The rectosigmoid is the most frequent location of intestinal endometriosis. Although several techniques have been proposed for the diagnosis of intestinal endometriosis, no gold standard is currently available. In this review, we describe in details a new technique for the diagnosis of rectosigmoid endometriosis: rectal water-contrast transvaginal ultrasonography. METHODS: During transvaginal ultrasonography, an assistant inserts a 6-mm flexible catheter through the anal os into the rectal lumen; the insertion of this catheter is evaluated under ultrasonographic control. Water contrast is instilled slowly in the rectum to permit intestinal distension. The colonic wall evaluation is obtained by positioning the transvaginal probe against a length of the sigmoid colon to obtain either axial or longitudinal images. The injection of the saline solution facilitates the identification of recto-sigmoid endometriotic nodules which appear as rounded or triangular hypoechoic masses, located anterior or lateral to the bowel. RESULTS: This technique has high sensitivity and specificity in the diagnosis of rectal infiltration in women with rectovaginal endometriosis. The distance between the nodules and the mucosal layer permits to estimate the depth of infiltration of these endometriotic lesions within the intestinal wall. Rectal distensibility can be estimated. The procedure is well tolerated by the patients. CONCLUSION: Water distension of the rectum facilitates the identification of intestinal endometriosis during transvaginal ultrasonography.


Subject(s)
Endometriosis/diagnostic imaging , Rectal Diseases/diagnostic imaging , Water , Female , Humans , Ultrasonography/methods , Vagina
12.
Mutat Res ; 321(4): 219-28, 1994 Jun.
Article in English | MEDLINE | ID: mdl-7515160

ABSTRACT

Cyanazine, cyhexatin, dicamba and DNOC are pesticides commonly and broadly used in agriculture pest control. However, there is little information on their toxicity and mutagenicity in human cells and in whole animals. Therefore, UDS assay and SCE assay in human peripheral lymphocytes, and chromosome aberration analysis in bone marrow of rats have been used to assess the DNA-damaging activity of the above pesticides. Cyanazine proved non-genotoxic in all the test systems. Cyhexatin showed only weakly positive results for SCE induction in human lymphocytes, providing no concern for genotoxicological hazard. While dicamba did not show clastogenic effects in rodents, DNOC gave significant dose-related increases of structural chromosome aberrations in rat bone marrow cells. Female animals showed increased sensitivity to the toxic effects by DNOC at the highest dose. The results provide further information on the intrinsic genotoxic activity of the tested pesticides, which may contribute to the toxicological assessment of the risk associated with human exposure.


Subject(s)
Mutagenicity Tests/methods , Mutagens/toxicity , Pesticides/toxicity , Animals , Bone Marrow/drug effects , Chromosome Aberrations , Dicamba/toxicity , Dinitrocresols/toxicity , Evaluation Studies as Topic , Female , Herbicides/toxicity , Humans , Insecticides/toxicity , Lymphocytes/drug effects , Male , Rats , Rats, Sprague-Dawley , Salmonella typhimurium/drug effects , Salmonella typhimurium/genetics , Trialkyltin Compounds/toxicity , Triazines/toxicity
13.
Pharmacol Toxicol ; 74(4-5): 249-54, 1994.
Article in English | MEDLINE | ID: mdl-8090695

ABSTRACT

Acute intraperitoneal administration of benzo(a)pyrene (80 mg/kg b.wt.) resulted in time-dependent increases in chromosome aberrations, especially of break-type in the bone marrow of treated mice. Pretreatment with murine interferon-alpha/beta (5 x 10(4) IU daily for two days) caused a significative decrease in the cytogenetic response in vivo of benzo(a)pyrene (up to 51%) and a stabilization of aberrant cells up to 48 hr. The administration of murine interferon-alpha/beta gave rise to a marked depression of microsomal monooxygenase system after 24 hr, as exemplified by the significant reduction of cytochrome P450 content as well as deethylation of ethoxyresorufin. Interferon treatment delayed the obtainment of basal levels of oxidative metabolism to approximately 30 hr. After interferon plus benzo(a)pyrene treatment, ethoxyresorufin O-deethylase activity showed a reduction up to 60%; levels comparable to benzo(a)pyrene treated group were restored by 48 hr. Immunoblotting analysis confirmed reduced CYP1A1 level. Results suggest that the inhibition of benzo(a)pyrene hepatic metabolism by interferon was reflected by changes in its clastogenic activity. Persistence of low level of chromosome aberration at 48 hr may be reconducible to other interferon sensitive processes than effects on hepatic mixed-function oxidase system, such as DNA repair activity and cell proliferation.


Subject(s)
Benzo(a)pyrene/metabolism , Bone Marrow/drug effects , Chromosome Aberrations , Interferon-alpha/pharmacology , Interferon-beta/pharmacology , Animals , Benzo(a)pyrene/toxicity , Biotransformation/drug effects , Cytochrome P-450 CYP1A1 , Cytochrome P-450 Enzyme System/metabolism , Injections, Intraperitoneal , Male , Mice , Microsomes, Liver/drug effects , Mutagenesis/drug effects , Oxidoreductases/metabolism , Time Factors
14.
Mutagenesis ; 8(3): 183-8, 1993 May.
Article in English | MEDLINE | ID: mdl-8332079

ABSTRACT

Nitrobenzimidazole and nitroindole derivatives, related to oxiconazole and characterized by an oxyiminic function, have been synthesized as novel antimycotics and their mutagenic activity tested in Salmonella typhimurium strains TA100 and TA98 with and without an exogenous metabolizing system. TA98NR and TA98/1,8-DNP6 strains were employed to identify a specific metabolic reaction which governs the mutagenic potency. Active compounds are weak direct-acting mutagens. Only derivatives bearing a nitro group on the phenyl ring linked to the oxyiminic function and lacking halogenated substituents show mutagenic activity. Metabolism by bacterial enzyme systems is important to the expression of genotoxicity. The reductive activation of nitrobenzimidazoles and nitroindoles carried out by the 'classical' nitroreductase of Salmonella, which is defective in TA98NR, is required of mutagenicity. Similarly, the O-acetyltransferase defective in TA98/1,8-DNP6 is required for the efficient production of the ultimate electrophilic nitrogen species, which react with DNA. The role of bacterial metabolism in mutation induction needs careful consideration to assess the potential risk to humans from nitrobenzimidazole and nitroindole antimycotics.


Subject(s)
Antifungal Agents/toxicity , Benzimidazoles/toxicity , Indoles/toxicity , Mutagenicity Tests , Mutagens/toxicity , Nitro Compounds/toxicity , Salmonella typhimurium/drug effects , Biotransformation , Humans , Molecular Conformation , Molecular Structure , Structure-Activity Relationship
15.
Chem Biol Interact ; 86(3): 229-54, 1993 Mar.
Article in English | MEDLINE | ID: mdl-8485786

ABSTRACT

The mutagenic activity of 23 5-nitro-3-thiophenecarboxanilides and of 5-nitro-3-thiophenecarboxamide, the prototype, (NTCAs) have been evaluated in the Ames test on Salmonella typhimurium strains TA100 ad TA98 with and without metabolic activation. Effects of different substituents (electron-donating and electron-withdrawing) were studied to evaluate structural features that affect the metabolism and the bacterial mutagenic potency. All the derivatives were direct-acting mutagens, the mutagenic potency ranging from 0.7 to 142 revertants (rev.)/nmol in TA100 and from 0.09 to 68 rev./nmol in TA98 strain. Results obtained with strains TA98NR and TA98/1,8-DNP6 indicated that the mutagenic activity was largely dependent on bacterial nitroreductase, whereas the O-acetylation step was not critical for mutagenic potency. Superoxide (O2-.) and hydroxyl (OH.) scavengers as well as other radical scavengers and enzymes inhibited NTCAs mutagenicity to different extents. In particular, O2-. seemed to be involved in NTCAs mutagenicity, showing a free radical pathway for NTCA metabolism. [1H]- and [13C]NMR data indicated that the effects of different substituents on genotoxicity are probably not exerted on the electron density distribution. The importance of factors such as extent of nitration, reduction potential, orientation of nitrosubstituent and planarity of the molecule are discussed.


Subject(s)
Mutagens/toxicity , Thiophenes/toxicity , Acetyltransferases/metabolism , Free Radicals , Magnetic Resonance Spectroscopy , Mutagenicity Tests , Mutagens/chemistry , Nitroreductases/metabolism , Salmonella typhimurium/drug effects , Salmonella typhimurium/enzymology , Structure-Activity Relationship , Thiophenes/chemistry
16.
Basic Life Sci ; 61: 325-34, 1993.
Article in English | MEDLINE | ID: mdl-8304945

ABSTRACT

In addition to their antiviral and immune regulatory properties, interferons (IFNs) are known to depress hepatic cytochrome P450-dependent metabolism. As many chemical mutagens and carcinogens require bioactivation by the mixed-function monooxygenase (MFO) system in order to be genotoxic, a combined genetic and biochemical approach was used to establish whether IFNs could inhibit the activation of benzo(a)pyrene (BaP) to the ultimate clastogenic metabolite(s) in vivo. Treatment of mice with murine IFN-alpha/beta depressed cytochrome P450 content, as well as ethoxyresorufin O-deethylase activity (EROD), as a probe of class IA1 P450 isozymes, for 24 hrs and delayed the attainment of normal levels to approximately 30 hrs. After IFNs plus BaP treatment, EROD activity showed a reduction up to 70% after 24 hrs with an enhancement in activity at 30 hrs. A positive correlation exists between the rate of inhibition of oxidative BaP hepatic metabolism and inhibition of clastogenic effects in vivo, as scored in the bone marrow chromosome aberration assay.


Subject(s)
Anticarcinogenic Agents/pharmacology , Benzo(a)pyrene/metabolism , Benzo(a)pyrene/toxicity , Interferon Type I/pharmacology , Microsomes, Liver/metabolism , Animals , Biotransformation , Bone Marrow/drug effects , Chromosome Aberrations , Cytochrome P-450 CYP1A1 , Cytochrome P-450 Enzyme System/metabolism , Male , Mice , Mice, Inbred Strains , Microsomes, Liver/drug effects , Oxidoreductases/metabolism
17.
Carcinogenesis ; 12(5): 759-66, 1991 May.
Article in English | MEDLINE | ID: mdl-1903089

ABSTRACT

The use of Aroclor 1254 to induce S9 liver fractions is a standard method for conducting short-term genotoxicity assays. An alternative induction procedure, using beta-naphthoflavone (beta-NF), as a safe (non-carcinogenic) substitute for polychlorinated biphenyls, combined with sodium phenobarbital (PB), was found to be equally effective. The aim of this work is to realize a novel schedule of induction for the preparation of metabolizing systems containing a wider spectrum of induced cytochrome P450s. Five inducers of different 'classes' such as PB (class IIB P450s), beta-NF (IA), isosafrol (IA2), ethanol (IIE1) and pregnenolone 16 alpha-carbonitrile (IIIA) were injected daily both separately (to achieve maximal monooxygenase induction) in male and female mice. Induction was monitored using specific P450-linked activities. In the optimal schedule for complete induction, the various monooxygenases were greater (2- to 4-fold) than those achieved by the classical schedule. More than a 14-fold increase of total P450 and 3.3-fold increase of NADPH-cytochrome (P450) c-reductase activity, over those uninduced, account for the above increase. For example, there was a marked increase in the deethylation of ethoxyresorufin (37-fold) compared to the uninduced mice that was considerably higher than classical induction (8-fold over uninduced). On the contrary, phase II reactions i.e. epoxide hydrolase, glutathione S-transferase, glutathione S-epoxide transferase and UDP-glucuronosyl transferase, examined to compare the phase I/phase II ratios in the traditional and proposed procedures, were increased to a lesser extent (2-fold over uninduced). No significant sex differences were seen. Five precarcinogens specifically metabolized by each of the induced P450s elicited a higher mutagenicity response in the presence of superinduced fractions with respect to the classical one, when tested on Salmonella typhimurium (cyclophosphamide, benzo[alpha]pyrene, 2-naphthylamine and dimethylnitrosamine) or Saccharomyces cerevisiae D7 strain (diethylstilbestrol). These novel metabolizing biosystems, with an enhanced spectrum of induced P450s and oxidative/post-oxidative reaction rates, are recommended for detecting unknown xenobiotics in genotoxicity studies.


Subject(s)
Biotransformation , Carcinogens/pharmacokinetics , Cytochrome P-450 Enzyme System/biosynthesis , Isoenzymes/biosynthesis , Liver/drug effects , Animals , Cytochrome P-450 CYP1A1 , Cytochrome P-450 CYP2B1 , Cytochrome P-450 CYP2E1 , Cytochrome P-450 Enzyme System/metabolism , DNA Damage , Enzyme Induction , Female , Hydroxylation , Liver/enzymology , Male , Mice , Mixed Function Oxygenases/metabolism , Mutagenicity Tests , NADPH-Ferrihemoprotein Reductase/metabolism , Oxidoreductases/metabolism
19.
Teratog Carcinog Mutagen ; 10(3): 263-71, 1990.
Article in English | MEDLINE | ID: mdl-1975130

ABSTRACT

Mutagenicity and carcinogenicity of metronidazole (MT) are imputable to the formation of toxic intermediates, which include radical forms derived from the nitroreductive process. Since dimethylsulfoxide (DMSO), the "universal" solvent, can quench free radicals in vitro, it was suggested that DMSO might protect by scavenging free radical generation in vivo. This study wanted to evaluate if DMSO (given concomitantly or prophylactically) protects against the organospecific mutagenicity of MT in vivo by means of the intrasanguineous host-mediated assay. DMSO used as solvent showed a 20%-30% reduction in the mutation frequencies by MT. Prophylactic administration of DMSO for 3 d caused a suppression of the organospecific mutagenicity. However, some increases in the spontaneous mutation frequency and enhancement of MT mutagenicity in kidney were observed. The protective effect was paralleled by a decrease in NADPH cytochrome c (P450) reductase in liver, kidney, and to a lesser extent in lung microsomes from pretreated mice. Inhibition of mutagenic activity might be related to scavenging of radical species as supported by the lack of tissue specificity and no appreciable changes in specific enzyme activity. However, changes in reductase content in prophylactically pretreated mice can affect the quantitative biotransformation of MT to the proximal mutagen contributing to the observed suppression in mutation frequencies.


Subject(s)
Dimethyl Sulfoxide/pharmacology , Metronidazole/toxicity , Mutation , Animals , Biotransformation/drug effects , Kidney/drug effects , Kidney/enzymology , Liver/drug effects , Lung/drug effects , Lung/enzymology , Male , Metronidazole/pharmacokinetics , Mice , Microsomes/enzymology , Microsomes, Liver/drug effects , Microsomes, Liver/enzymology , Mutagenicity Tests , NADPH-Ferrihemoprotein Reductase/metabolism
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