Mutagenicity and DNA adduct formation by the urban air pollutant 2-nitrobenzanthrone.

2-Nitrobenzanthrone (2-NBA) has recently been detected in ambient air particulate matter. Its isomer 3-nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust. The highest mutagenic activity of 2-NBA tested in Salmonella typhimurium was exhibited in strain TA1538-hSULT1A1 expressing human sulfotransferase (SULT) 1A1. 2-NBA also induced mutations in Chinese hamster lung V79 cells expressing human N-acetyltransferase 2 or SULT1A1, but no mutagenicity was observed in the parental cell line. DNA adduct formation in vitro was examined in different human cell lines by thin-layer chromatography (32)P-postlabeling. Whereas 3-NBA formed characteristic DNA adducts in lung A549, liver HepG2, colon HCT116, and breast MCF-7 cells, 2-NBA-derived DNA adducts were only observed in A549 and HepG2 cells, indicating differences in the bioactivation of each isomer. The pattern of 2-NBA-derived DNA adducts in both cell lines consisted of a cluster of up to five adducts. In HepG2 cells DNA binding by 2-NBA was up to 14-fold lower than by 3-NBA. DNA adduct formation of 2-NBA was also investigated in vivo in Wistar rats treated with a single dose of 2, 10, or 100 mg/kg body weight (bw). No DNA adduct formation was detected at doses of up to 10 mg/kg bw 2-NBA, even though 3-NBA induced DNA adducts at a dose of 2 mg/kg bw. Only after administration of one high dose of 100 mg/kg bw 2-NBA was a low level of DNA adduct formation detected, and then only in lung tissue. Density functional theory calculations for both NBAs revealed that the nitrenium ion of the 3-isomer is considerably more stable ( approximately 10 kcal/mol) than that of the 2-isomer, providing a possible explanation for the large differences in DNA adduct formation and mutagenicity between 2- and 3-NBA.     

Studies on the importance of microsomal epoxide hydrolase in the detoxification of arene oxides using the heterologous expression of the enzyme in mammalian cells

In order to investigate the role of the microsomal epoxide hydrolase(mEH) in the detoxification of arene oxides in the presenceof a high endogenous glutathione S-transferase (GST) activity—asituation found in several organs—we expressed the ratmEH cDNA in BHK21 Syrian hamster cells. These cells have highGST activities but contain an extremely low endogenous mEH enzymeactivity. We obtained several cell clones which expressed themEH heterologously, as determined by immunoblotting. The cellclone BHK21-mEH/Mz1 had the highest level of mEH protein. Immuno-fluorescenceshowed that the level of expression was almost homogeneous throughoutthe cell population. Total protein isolated from the cell lineBHK21-mEH/Mzl had a specific mEH activity of 123 pmol/min/mgprotein, as determined with benzo[     

A CT Database for Research,Development and Education: Concept and Potential

Both in radiology and in surgery, numerous applications are emerging that enable 3D visualization of data from various imaging modalities. In clinical practice, the patient's images are analyzed on work stations in the Radiology Department. For specific preclinical and educational applications, however, data from single patients are insufficient. Instead, similar scans from a number of individuals within a collective must be compiled. The definition of standardized acquisition procedures and archiving formats are prerequisite for subsequent analysis of multiple data sets. Focusing on bone morphology, we describe our concept of a computer database of 3D human bone models obtained from computed tomography (CT) scans. We further discuss and illustrate deployment areas ranging from prosthesis design, over virtual operation simulation up to 3D anatomy atlases. The database of 3D bone models described in this work, created and maintained by the AO Development Institute, may be accessible to research institutes on request.     

Prevalence and contributors to fatigue in individuals hospitalized with advanced cancer: A prospective, observational study

BackgroundAlthough fatigue affects over 75% of patients with advanced cancer, changes over time in symptoms and antecedents have not been described in the acute care setting.ObjectivesTo determine the prevalence, in patients with advanced cancer, of fatigue and anaemia on admission, describe strategies used to treat anaemia, observe changes in fatigue over ten days, and determine factors associated with fatigue.DesignProspective, observational study.Settings and participantsIn two Swiss tertiary care hospitals, a convenience sample of patients (N = 103) was recruited at admission and followed up at days six (n = 76) and ten (n = 53). Patients were admitted because of new and/or worsening symptoms, deteriorating health status, or complications. They received measures aimed at symptom control and disease modifying interventions.MethodsClinical and sociodemographic data were collected on selected patients who were able to complete a test battery of validated measures. Assessment was undertaken on hospital admission and on days six and ten post-admission.FindingsAt admission, according to the suggested cut-off score of 43 for the FACIT-Fatigue scale, 87% of participants were experiencing cancer-related fatigue. Fatigue varied greatly within and among patients. Data on anaemia were available for 100 patients, of whom 62% were anaemic on admission. Severe and life threatening anaemia were mostly treated with red blood cell transfusions. Over time, fatigue decreased for patients who improved enough to be discharged (p < 0.001) but not for those who withdrew from the study, most of whom did so due to worsening health. In multiple regression analysis, younger patients and patients with lower functional status, higher scores for depression, and more other anaemia-related symptoms experienced more fatigue. The variables examined explained 62% of variance in fatigue.ConclusionsFatigue was common in hospitalized patients with advanced cancer and the majority were anaemic. Based on these data, monitoring and treating fatigue and anaemia over a ten-day hospital stay seem to be supported. The variable trajectories call for interventions carefully tailored to individual patients. The results should be considered as a first step to exploring fatigue in these patients.     

Conjugation of 4-nitrophenol and 4-hydroxylonazolac in V79-derived cells expressing individual forms of human sulphotransferases

Sulpho conjugation of xenobiotics is catalysed by enzymes of the SULT superfamily. We have studied the conjugation of two model compounds, 4-nitrophenol and 4-hydroxylonazolac, in cultures of V79-derived cell lines that individually express human SULT1A1 (alloenzymes *1 and *V), 1A2 (alloenzymes *1 and *2), 1A3, 1B1, 1E1, 2A1 and rat SULT1E1. 4-Nitrophenol was sulphonated in all recombinant cell lines used but not in the control cell line (V79p). The relative activity in the various cell lines strongly depended on the substrate concentration used (1–1000 μM). 4-Hydroxylonazolac was conjugated in the cell lines expressing the following enzymes, in this order, human SULT1E1>1A1 (*1>*V)>1A2 (*1>*2)>1A3. In all these cell lines, the rate of conjugation increased with the substrate concentration (1–100 μM) without reaching a saturation level. The mass spectrometric and fluorometric analyses used are very sensitive. Preliminary experiments demonstrate that activities can readily be measured in microtitre-plate cultures.     

Mutagenicity of arbutin in mammalian cells after activation by human intestinal bacteria.

Arbutin (hydroquinone-beta-D-glucopyranoside) is present in various food plants. Its aglycone, hydroquinone, is mutagenic and carcinogenic. We investigated whether hydroquinone may be released under conditions encountered in the human gastrointestinal tract. Arbutin was stable in artificial gastric juice. Fecal slurries from nine human subjects completely converted arbutin (2 mM) into hydroquinone. Four of nine representative human intestinal species investigated, namely Eubacterium ramulus, Enterococcus casseliflavus, Bacteroides distasonis, and Bifidobacterium adolescentis, deglycosylated arbutin at rates of 21.08, 16.62, 8.43 and 3.59 nmol x min(-1) x (mg protein)(-1), respectively. In contrast, homogenates from small intestinal mucosa and cytosolic fractions from colon mucosa deglycosylated arbutin at substantially lower rates: 0.50 and 0.09 nmol x min(-1) x (mg protein)(-1), respectively. Arbutin, unlike hydroquinone, did not induce gene mutations in Chinese hamster V79 cells in the absence of an activating system. However, in the presence of cytosolic fractions from E. ramulus or B. distasonis, arbutin was strongly mutagenic. Cytosolic fraction from Escherichia coli, showing no arbutin glycosidase activity, was not able to activate arbutin in this model system. The release of the proximate mutagen hydroquinone from arbutin by intestinal bacteria in the immediate vicinity of the colon mucosa may pose a potential risk.     

Reading nursing Literature in English: new inputs for practicing nurses

A prerequisite to providing evidence-based care is the ability to comprehend the nursing research literature, most of which is published in English. To facilitate this understanding, a course on "reading the research literature for evidence-based practice in English" was developed by an interdisciplinary team for staff nurses at the University Hospital Basel. The pilot course was offered to nurses who specialized in cancer care. It was led by the oncology Advanced Practice Nurse (APN) from the Department of Medicine. Research articles focusing on the management of chronic illness and cancer pain management were assigned and read. The course consisted of ten 90 minute lessons. The evaluation was designed to address the following questions: 1. Did participation in the course improve the oncology related knowledge of the nurses? 2. Did participation in the course improve the nurses' English language skills? 3. At what level of difficulty did the nurse participants perceive the course to be? 4. Were course participants able to use their newly acquired knowledge to teach their nursing colleagues on the ward? The course evaluation demonstrated that the 15 participants significantly improved their oncology knowledge through this process but that their English skills did not improve. The participants were able to present lectures on their wards based on the course literature, which were positively evaluated by their colleagues and the APN course leader. The participants perceived the course as being sophisticated but also effective at demonstrating the use of English-language research literature for one's own nursing practice.     

Structural elucidation of hydroxylated metabolites of the isoflavan equol by gas chromatography-mass spectrometry and high-performance liquid chromatography-mass spectrometry.

Equol has, as have other isoflavonoids, recently gained considerable interest due to its possible health effects. However, detailed studies on the metabolism of equol are scarce. Therefore, we investigated the phase I metabolism of equol using liver microsomes from Aroclor-treated male Wistar rats as well as from a male human. The identification of the metabolites formed was elucidated using high performance liquid chromatography (HPLC) with diode array detection, HPLC/atmospheric pressure ionization electrospray mass spectrometry, and gas chromatography-mass spectrometry, as well as reference compounds. (+/-)-Equol was converted to 11 metabolites by the liver microsomes from Aroclor-pretreated rats comprising three aromatic monohydroxylated and four aliphatic monohydroxylated as well as four dihydroxylated products. The main metabolite was identified as 3'-hydroxy-equol. Using human liver microsomes, equol was converted to six metabolites with 3'-hydroxy- and 6-hydroxy-equol as main products. Furthermore, the aliphatic hydroxylated metabolite 4-hydroxyequol, which was recently detected in human urine after soy consumption, was formed. On the basis of these findings, it is suggested that phase I metabolism of equol is part of a complex biotransformation of the soy isoflavone daidzein in humans in vivo.     

Stable expression of rat cytochrome P450IA2 cDNA and hydroxylation of 17 beta-estradiol and 2-aminofluorene in V79 Chinese hamster cells.

In continuation of our work toward the establishment of a working cell bank for metabolic and toxicological studies, V79 Chinese hamster cells were genetically engineered for stable expression of rat cytochrome P450IA2. Full-length cDNA encoding rat P450IA2 was obtained by searching a cDNA library made from Aroclor 1254-induced rat liver mRNA and by joining a small 5'-end fragment to a fragment containing the rest of the cDNA. The sequence of the cDNA was confirmed by DNA sequencing and comparison to a previously published cDNA sequence. The reconstructed full-length cDNA was inserted into a simian virus 40 early promoter-containing eukaryotic expression vector and cotransferred with the neomycin phosphotransferase gene as a selective marker into V79 cells by the calcium/phosphate-coprecipitation technique. G418-resistant V79 cell clones were checked for chromosomal integration of the cDNA by Southern blotting, for expression of authentic mRNA and protein by northern and western blotting, and for P450IA2-specific enzymatic activities such as hydroxylation of 17 beta-estradiol and 2-aminofluorene.