bluuebunny/crossref_metadata_2025_split huggingface dataset:
Food transport in theC. eleganspharynx
Authors: Avery Leon , Shtonda Boris B. 
Published: June 2003

SUMMARYPumping of the C. elegans pharynx transports food particles(bacteria) posteriorly. We examined muscle motions to determine how this posterior transport is effected. We find that the motions of the middle section of the pharynx, the anterior isthmus, are delayed relative to the anterior section, the corpus. Simulations in which particles are assumed to move at mean fluid velocity when not captured by the walls of the pharyngeal lumen show that delayed isthmus motions do indeed cause net particle transport; however, the amount is much less than in the real pharynx. We propose that the geometry of the pharyngeal lumen forces particles to the center, where they move faster than mean fluid velocity. When this acceleration is incorporated into the simulation, particles are transported efficiently. The transport mechanism we propose explains past observations that the timing of muscle relaxation is important for effective transport. Our model also makes a prediction, which we confirm, that smaller bacteria are better food sources for C. elegans than large ones.
Central circuitry in the jellyfishAglantha digitaleIV. Pathways coordinating feeding behaviour
Authors: Mackie G. O. , Marx R. M. , Meech R. W. 
Published: June 2003

SUMMARYThe hydromedusan jellyfish Aglantha digitale feeds on small planktonic organisms carried to the margin by tentacle flexions. During feeding, the manubrium bends across (`points') and seizes the prey with flared lips. In immobilized preparations, pointing to a source of electrical stimulation was accurate, 70% of the time, to within 15°. Cutting experiments showed that the conduction pathways concerned with pointing and lip flaring are located in eight radial strands consisting of a radial canal,a giant nerve axon and a bundle of small axons with FMRFamide-like immunoreactivity.Application of food juices to sites on the margin and tentacles evoked trains of impulses in the axon bundles (F events; conduction velocity 15.5±3.7 cm s-1) and in the epithelium lining the radial canals (E events; conduction velocity 28.5±3.5 cm s-1). Impulses were conducted circularly in the outer nerve ring (F events) or in the ring canal (E events).Unilateral flexions of the manubrium during pointing arise from preferential excitation of one or more of eight longitudinal `muscle bands' in the wall of the manubrium and peduncle. Lip flaring represents symmetrical contraction of all eight bands. Cutting experiments revealed that F events mediate pointing; E events mediate lip flaring. Thus the endodermal radial canals, which in other hydromedusae mediate protective `crumpling', provide the conduction pathway for manubrial lip flaring. Aglantha's alternative protective response – escape swimming – makes crumpling unnecessary, releasing the pathway for use in feeding.Trains of E events, generated in the manubrium during ingestion, propagate to the margin and inhibit rhythmic (slow) swimming with a duration that depended on their number and frequency. Inhibition of swimming appeared to facilitate transfer of food from the margin to the mouth, but how it comes about is unclear.
Mutagenicity, antioxidant potential, and antimutagenic activity against hydrogen peroxide of cashew (Anacardium occidentale) apple juice and cajuina
Authors: Melo Cavalcante Ana Amélia , Rubensam Gabriel , Picada Jaqueline N. , Gomes da Silva Evandro , Fonseca Moreira José Claúdio , Henriques João A.P. 
Published: June 2003

AbstractFresh and processed cashew (Anacardium occidentale) apple juice (CAJ) are among the most popular drinks in Brazil. Besides their nutritional benefits, these juices have antibacterial and antitumor potential. The chemical constituents of both the fresh juice and the processed juice (cajuina) were analyzed and characterized as complex mixtures containing high concentrations of vitamin C, various carotenoids, phenolic compounds, and metals. In the present study, these beverages exhibited direct and rat liver S9‐mediated mutagenicity in the Salmonella/microsome assay with strains TA97a, TA98, and TA100, which detect frameshifts and base pair substitution. No mutagenicity was observed with strain TA102, which detects oxidative and alkylating mutagens and active forms of oxygen. Both CAJ and cajuina showed antioxidant activity as determined by a total radical‐trapping potential assay. To test whether this antioxidant potential might result in antimutagenesis, we used a variation of the Salmonella/microsome assay that included pre‐, co‐, and posttreatment of hydrogen peroxide‐exposed Salmonella typhimurium strain TA102 with the juices. CAJ and cajuina protected strain TA102 against mutation by oxidative damage in co‐ and posttreatments. The antimutagenic effects during cotreatment with hydrogen peroxide may be due to scavenging free radicals and complexing extracellular mutagenic compounds. The protective effects in posttreatment may be due to stimulation of repair and/or reversion of DNA damage. The results indicate that CAJ and cajuina have mutagenic, radical‐trapping, antimutagenic, and comutagenic activity and that these properties can be related to the chemical constituents of the juices. Environ. Mol. Mutagen. 41:360–369, 2003. © 2003 Wiley‐Liss, Inc.
Positive correlation between the frequency of micronucleated cells and dysplasia in Papanicolaou smears
Authors: Guzmán Patricia , Sotelo‐Regil Rita C. , Mohar Alejandro , Gonsebatt María E. 
Published: June 2003

AbstractMost cancers arise in epithelial tissues and these tissues are typically the targets of the carcinogens responsible for the tumors. Exfoliated epithelial cells have traditionally been used for cancer screening by cytopathologists and these cells also can be used for biomonitoring of genotoxic effects in humans. Cervical cancer results from the progression of preinvasive precursor lesions, called low‐grade squamous intraepithelial lesions (LGSILs), to high‐grade squamous intraepithelial lesions (HGSILs). The gradient from low to high‐grade lesions is characterized by increasing nuclear atypia and the failure of cellular differentiation in progressively more superficial levels of the epithelium. These phenotypic changes are hypothesized to be accompanied by increased genetic instability that can be documented using the micronucleus (MN) assay in exfoliated cervical cells. A retrospective study was performed to investigate the frequency of micronucleated cells in cervical smears from women at high risk for developing cervical cancer. Papanicolaou (Pap) smears from 275 women previously studied at a cancer clinic were coded and analyzed for the frequency of micronucleated cells. LGSIL, HGSIL, and invasive carcinoma smears had significantly higher frequencies than normal and ASCUS (abnormal squamous cells of undetermined origin) smears. HGSIL or severely dysplastic smears had the highest frequency of micronucleated cells (although not significantly higher than LGSIL smears), an observation that that could be useful in confirming these types of lesions. The results indicate that the MN frequency in exfoliated cervical cells may be an additional criterion for establishing cervical cancer risk. Environ. Mol. Mutagen. 41:339–343, 2003. © 2003 Wiley‐Liss, Inc.
Genotoxicity of surface water treated with different disinfectants using in situ plant tests
Authors: Monarca S. , Rizzoni M. , Gustavino B. , Zani C. , Alberti A. , Feretti D. , Zerbini I. 
Published: June 2003

AbstractDisinfection of surface drinking water, in particular water chlorination, results in many by‐products with potential genotoxic and/or carcinogenic activity. In the present study, we evaluated the genotoxicity of surface water after treatment with different disinfectants by means of in situ plant genotoxicity assays (micronucleus and chromosomal aberration tests) which can detect both clastogenic and aneugenic effects. The study was carried out at a pilot plant using lake water after sedimentation and filtration. This water supplied four stainless steel basins: three basins were disinfected with sodium hypochlorite, chlorine dioxide, and peracetic acid and the fourth basin containing untreated lake water was used as a control. Plants were exposed in situ in the basins. The study was carried out using water collected in different seasons over a period of about 1 year in order to assess the treatments in different physical and chemical lake water conditions. The micronucleus test in root cells of Vicia faba (Vicia faba/MCN test) revealed genotoxicity in many samples of disinfected water. The micronucleus test in Tradescantia pollen cells and the chromosome aberration test in root cells of Allium cepa showed genotoxic effects only in some disinfected samples, but also revealed genotoxicity in raw water. The results of the study indicated that the Vicia faba/MCN test was the most sensitive plant assay for disinfected water and that peracetic acid disinfection produced similar or lower genotoxicity than sodium hypochlorite or chlorine dioxide treatment. Environ. Mol. Mutagen. 41:353–359, 2003. © 2003 Wiley‐Liss, Inc.
Cell‐cycle deregulation in BALB/c 3T3 cells transformed by 1,2‐dibromoethane and folpet pesticides
Authors: Santucci Maria Alessandra , Mercatali Laura , Brusa Gianluca , Pattacini Laura , Barbieri Enza , Perocco Paolo 
Published: June 2003

AbstractThe cell‐transforming potential of 1,2‐dibromoethane and folpet, two widely used agricultural pesticides that are potential sources of environmental pollution, has been previously ascribed to their promoting activity. In this study, we investigated whether BALB/c 3T3 transformation by these chemicals was associated with the deregulation of signals involved in cell‐cycle progression and in cell‐cycle checkpoint induction. We found that two BALB/c 3T3 cell clones transformed by in vitro medium‐term (8‐week) exposure to the carcinogens had a constitutive acceleration of cell transition from G1 to S phase and an abrogation of the radiation‐induced G1/S checkpoint. These events involved multiple signals; in particular, the inhibitors of cyclin/cyclin‐dependent kinase complexes p21 and p27 were significantly down‐modulated and the positive regulators of cell‐cycle progression cyclin D3 and E were up‐modulated. As anticipated for cells where the G1/S checkpoint was abrogated, the transformed cells exhibited a significant reinforcement of the radiation‐induced G2/M checkpoint, the only checkpoint remaining to protect genomic integrity. However, cyclin A1 and B1 coexpression and cyclin A1 overexpression were found despite the G2 arrest in irradiated cells and these signals likely attenuate the G2/M checkpoint. These alterations to normal cell cycling may promote the emergence of both numerical and structural chromosomal abnormalities and their tolerance. Such a condition could play a key role in neoplastic transformation and be crucial in tumor progression. Furthermore, cyclin A1 overexpression may play an autonomous role in the neoplastic transformation of BALB/c 3T3 cells, as it does in other cell types of mesenchymal origin. Environ. Mol. Mutagen. 41:315–321, 2003. © 2003 Wiley‐Liss, Inc.
Altered expression of zinc finger proteins, ADAMs, and integrin‐related proteins following treatment of cultured human cells with a low concentration of N‐methyl‐N′‐nitro‐N‐nitrosoguanidine
Authors: Jin Jinghua , Gao Zhihua , Guo Lei , Yang Jun , Yu Yingnian 
Published: June 2003

AbstractProteomic analysis is an important approach to characterize the proteome and study protein functions. It is also a powerful screening method for detecting unexpected alterations in protein expression that may be overlooked by conventional biochemical techniques. N‐Methyl‐N′‐nitro‐N‐nitrosoguanidine (MNNG) is an alkylating agent that can induce nontargeted mutagenesis in treated cells, although the mechanism remains unclear. Using an efficient proteomic method, we identified several cellular proteins that are responsive to low‐concentration MNNG treatment in human FL cells. After MNNG treatment, whole cellular proteins were separated using two‐dimensional gel electrophoresis and visualized by silver staining; the digitized images then were analyzed with 2D analysis software. More than 60 proteins showed significant changes in MNNG‐treated cells compared to control cells (DMSO treatment). Thirty‐one proteins only detected in MNNG‐treated or control cells were subjected to in‐gel digestion with trypsin and identified by matrix‐assisted laser desorption ionization‐time of flight (MALDI‐TOF) mass spectrometry using peptide mass fingerprinting. Eighteen of theses proteins have been identified, including several zinc finger proteins, two members of the ADAMs (a disintegrin and metalloprotease domain) family, and two integrins. Most of these proteins have unknown functions and their involvement in the cellular responses to alkylating agents have not been reported. Therefore, our findings may offer new insights into the mechanisms of low‐concentration MNNG‐induced nontargeted mutagenesis and these proteins may serve as new biomarkers for detecting exposure of human populations to environmental carcinogens. Environ. Mol. Mutagen. 41:344–352, 2003. © 2003 Wiley‐Liss, Inc.
Arsenite induces delayed mutagenesis and transformation in human osteosarcoma cells at extremely low concentrations
Authors: Mure Kanae , Uddin Ahmed N. , Lopez Laura C. , Styblo Miroslav , Rossman Toby G. 
Published: June 2003

AbstractArsenite is a human multisite carcinogen, but its mechanism of action is not known. We recently found that extremely low concentrations (≤0.1 μM) of arsenite transform human osteosarcoma TE85 (HOS) cells to anchorage‐independence. In contrast to other carcinogens which transform these cells within days of exposure, almost 8 weeks of arsenite exposure are required for transformation. We decided to reexamine the question of arsenite mutagenicity using chronic exposure in a spontaneous mutagenesis assay we previously developed. Arsenite was able to cause a delayed increase in mutagenesis at extremely low concentrations (≤0.1 μM) in a dose‐dependent manner. The increase in mutant frequency occurred after almost 20 generations of growth in arsenite. Transformation required more than 30 generations of continuous exposure. We also found that arsenite induced gene amplification of the dihydrofolate reductase (DHFR) gene in a dose‐dependent manner. Since HOS cells are able to methylate arsenite at a very low rate, it was possible that active metabolites such as monomethylarsonous acid (MMAIII) contributed to the delayed mutagenesis and transformation in these cells. However, when the assay was repeated with MMAIII, we found no significant increase in mutagenesis or transformation, suggesting that arsenite‐induced delayed mutagenesis and transformation are not caused by arsenite's metabolites, but by arsenite itself. Our results suggest that long‐term exposure to low concentrations of arsenite may affect signaling pathways that result in a progressive genomic instability. Environ. Mol. Mutagen. 41:322–331, 2003. © 2003 Wiley‐Liss, Inc.
Analysis of 8‐hydroxydeoxyguanosine 5′‐monophosphate (8‐OH‐dGMP) as a reliable marker of cellular oxidative DNA damage after γ‐irradiation
Authors: Mei Nan , Tamae Kazuyoshi , Kunugita Naoki , Hirano Takeshi , Kasai Hiroshi 
Published: June 2003

AbstractIn order to improve 8‐hydroxyguanine (8‐OH‐Gua) detection in DNA, we digested isolated DNA with nuclease P1 and analyzed for 8‐hydroxydeoxyguanosine 5′‐monophosphate (8‐OH‐dGMP) using a high‐performance liquid chromatography system equipped with an electrochemical detector (HPLC‐ECD). The amount of 8‐OH‐Gua in the DNA was expressed as the ratio of 8‐OH‐dGMP to deoxycytidine monophosphate (dCMP). Using this analysis, the background level of 8‐OH‐Gua in DNA from human lung carcinoma cells (A549) was several‐fold lower than that obtained by a previous method. A549 cells were exposed to 20–60 Gy of γ‐radiation and an increase in 8‐OH‐Gua concentration was observed with increasing γ‐ray dose (0.3 residues per 107 dCMP per Gy). Moreover, by an immunohistochemical procedure using a commercial FITC‐kit, 8‐OH‐Gua was clearly detected in A549 cells and the fluorescence intensity of cells with oxidative DNA damage increased with the doses of γ‐irradiation. Using an endonuclease nicking assay, we also found that γ‐rays decreased 8‐OH‐Gua repair activity. The results indicate that 8‐OH‐dGMP is a useful and sensitive marker for estimating oxidative damage in DNA. Environ. Mol. Mutagen. 41:332–338, 2003. © 2003 Wiley‐Liss, Inc.
Seasonal variations in the onset of childhood leukemia/lymphoma: April 1996 to March 2000, Shiraz, Iran
Authors: Karimi Mehran , Yarmohammadi Hooman 
Published: June 2003

AbstractInfection has long been suspected as a possible factor in the aetiology of leukemia and lymphoma, one of the most common malignancies in children. Since most viral infections have seasonal variations of onset, if seasonal trends in 1 month of diagnosis of leukemia and lymphoma could be proved, this would be supportive evidence for an infectious aetiology. A total of 367 cases in the Hospitals of Shiraz University of Medical Sciences, from April 1996 through March 2000, who were diagnosed as having acute lymphocytic leukemia (ALL), acute myeloblastic leukemia (AML), Burkitt's lymphoma (BL) chronic myeloblastic lymphoma (CML), Hodgkin's disease (HD) or non‐Burkitt's type non‐Hodgkin's lymphoma (NBNHL) were analysed. The month of appearance of the first symptom and the date of diagnosis were recorded. ALL demonstrated statistically significant monthly variation in the date of appearance of the first symptom (p < 0.05; peak in October) and the date of diagnosis (p < 0.05; peak in November). Seasonal variation was demonstrated in the date of the first appearance of symptoms in BL (p < 0.042), and in the date of diagnosis in AML (p < 0.049). There was no statistically significant seasonal variation in the month of diagnosis for other groups. Analysis based on the date of the first symptoms and the date of diagnosis for ALL patients, using summer–winter ratios, also showed a significant winter excess (p < 0.001). Our data provide modest support for an autumn–winter peak in the diagnosis of childhood ALL, underlying mechanisms that account for these patterns are likely to be complex and need more definitive studies. Copyright © 2003 John Wiley & Sons, Ltd.
The effects of STI571 on antigen presentation of dendritic cells generated from patients with chronic myelogenous leukemia
Authors: Sato Naoko , Narita Miwako , Takahashi Masuhiro , Yagisawa Kumiko , Liu Aichun , Abe Takashi , Nikkuni Kohji , Furukawa Tatsuo , Toba Ken , Aizawa Yoshifusa 
Published: June 2003

AbstractChronic myelogenous leukemia is caused by the acquisition of the reciprocal (9;22)(q34;q11) chromosomal translocation in hematopoietic stem cells. The fusion protein showed higher and aberrant tyrosine kinase activity. The inhibition of the tyrosine kinase activity of the protein represents a specific therapeutic strategy for bcr/abl‐expressing leukemias. STI571 is a compound of the 2‐phenylaminopyrimidine class that selectively inhibits the tyrosine kinase activity of the Abl protein tyrosine kinase. In this study, we evaluated the effects of STI571 on antigen presentation of dendritic cells generated from the patients with CML. The data showed that by the addition of STI571 the dendritic cells derived from CML clone showed an increased expression of CD1a, CD83, CD80 and CD86 by flow cytometry analysis and showed more intense abilities of allogeneic antigen presentation by mixed leukocyte culture, compared with the control cells without STI571. Our results suggested that STI571 not only has a direct cytotoxic effect on bcr‐abl gene rearranged cells but also an indirect effect associated with increased anti‐leukemic immunological function due to an intensified antigen presentation. Copyright © 2003 John Wiley & Sons, Ltd.
Psychosomatic liaison service in hematological oncology: need for psychotherapeutic interventions and their realization
Authors: Fritzsche Kurt , Struss Yvonne , Stein Barbara , Spahn Claudia 
Published: June 2003

AbstractEmpirical investigations examining the psychosocial distress and need for care of inpatients with hematological malignancies are rare. Little is known about the use of psychotherapeutic interventions in routine care. To evaluate the psychosocial distress of hemato‐oncological inpatients, the need for psychotherapeutic interventions and their realization in the framework of a psychosomatic liaison service has been assessed. Seventy‐two patients from two hematological oncology wards underwent psychodiagnostic interviews and completed self‐rating instruments, elucidating mental disorders, psychosocial distress, coping strategies, quality of life, treatment motivation and psychotherapeutic interventions. Using ICD‐10 criteria, mental and behavioural disorders were diagnosed in 53% of patients. Professional assessment indicated a need for psychotherapeutic treatment in 49%, while 38% of the patients wished to receive psychological support. Actual intervention occurred for all patients in the bone marrow transplantation unit and for 23% of patients in the general hemato‐oncological ward. There is considerable need for psychotherapeutic treatment which can only be handled within the framework of a liaison service in close cooperation with oncologists, nurses and mental health specialists. Copyright © 2003 John Wiley & Sons, Ltd.
Empirical estimation of the effect of urban heat advection on the temperature series of De Bilt (The Netherlands)
Authors: Brandsma T. , Können G. P. , Wessels H. R. A. 
Published: June 2003

AbstractThe influence of urban heat advection on the temperature time series of the Dutch GCOS station De Bilt has been studied empirically by comparing the hourly meteorological observations (1993–2000) with those of the nearby (7.5 km) rural station at Soesterberg. Station De Bilt is in the transition zone (TZ) between the urban and rural area, being surrounded by three towns, Utrecht, De Bilt and Zeist. The dependence of the hourly temperature differences between De Bilt and Soesterberg on wind direction has been examined as a function of season, day‐ and night‐time hours and cloud amount. Strong dependence on wind direction was apparent for clear nights, with the greatest effects (up to 1 °C on average) for wind coming from the towns. The magnitude of the effect decreased with increasing cloudiness. The analysis suggests that most of the structure in the wind direction dependence is caused by urban heat advection to the measuring site in De Bilt. The urban heat advection is studied in more detail with an additive statistical model. Because the urban areas around the site expanded in the past century, urban heat advection trends contaminate the long‐term trends in the temperature series (1897–present) of De Bilt. Based on the present work, we estimate that this effect may have raised the annual mean temperatures of De Bilt by 0.10 ± 0.06 °C during the 20th century, being almost the full value of the present‐day urban heat advection. The 0.10 ± 0.06 °C rise due to urban heat advection corresponds to about 10% of the observed temperature rise of about 1.0 °C in the last century. Copyright © 2003 Royal Meteorological Society