bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selection of fetal bovine serum for use in the C3H/10T1/2 CL8 cell transformation assay system
Authors: Oshiro Y. , Balwierz P. S. , Piper C. E. 
Published: February 2007

AbstractThe purpose of this communication is to report our experience concerning the variation in cloning efficiency and transformation frequency utilizing C3H/10T1/2 CL8 cells with 23 different lots of fetal bovine sera. These sera were purchased from five different commercial sources. The standard cell transformation assay using 1,000 cells per dish and 3‐methylcholanthrene (7.5 μg/ml) as the transforming agent was performed. The chemical exposure period was 3 days. The cloning efficiency was determined in parallel toxicity tests using 200 cells per dish. Only three out of 23 serum lots supported a strong response in cell transformation. The results indicated that variation in the ability of sera to support cell transformation was not supplier dependent. In addition, our results showed that serum lots exhibiting the best cloning efficiencies did not necessarily support cell transformation. It is apparent that reliance on cloning efficiency alone would be inadequate as a means of selecting a serum lot. We therefore recommend that a complete cell transformation assay be performed when selecting fetal bovine serum for use in this assay.
Genetic effects of 1,2‐dibromo‐3‐chloropropane (DBCP) in drosophila
Authors: Kale P. G. , Baum J. W. 
Published: February 2007

AbstractInduction of sex‐linked recessive lethal mutations, heritable translocations and genetic crossing‐over were studied in Drosophila melanogaster males treated as adults and as embryos with different concentrations of gaseous DBCP. Adults exposed to 30 ppm/hr of the compound did not produce a significant number of sex‐linked recessive lethal mutations in treated spermatozoa, spermatids, or spermato‐cytes. However, at an exposure of 17.7 ppm/hr, a weak mutagenic effect was observed in embryonic spermatogonia. No translocation was scored in 4032 tested chromosomes from adults treated with 150 ppm/hr. However, a significant number of spermatocytial crossovers were induced after an exposure of 120 ppm/hr.
Complex effects of retinol on the metabolic activation of 2‐aminofluorene
Authors: Balbinder Elias , Stick Sally M. , Sharma Opendra K. 
Published: February 2007

AbstractIt has been reported that vitamin A alcohol (retinol) inhibits the mutagenicity of certain carcinogenic agents requiring metabolic activation by mammalian microsomal enzymes in the Ames Salmonella assay. We have found that the effect of retinol on the mutagenicity of 2‐aminofluorene (2AF), a carcinogen requiring metabolic activation, is complex and dependent both on the ratio of retinol (μg per plate) to S9 (μg of protein per plate), as well as the absolute concentration of retinol. Retinol had no effect on the mutagenicity of 4‐nitro‐o‐phenylenediamine (4NPDA), a direct‐acting mutagen. However, the mutagenicity of 4NPDA was inhibited by S9 and this inhibition was not affected by retinol.
Pesticide‐induced complete and partial chromosome loss in screens with repair‐defective females of drosophila melanogaster
Authors: Woodruff R. C. , Phillips J. P. , Irwin D. 
Published: February 2007

AbstractCommercial preparation of fungicides (captan and maneb), herbicides (bromacil, paraquat, picloram, and 2,4‐D), and insecticides (carbaryl, chlorpyrifos, dimethoate, DDT, diazinon, carbofuran, and permethrin) were tested for their ability to induce complete and partial chromosome losses in Drosophila melanogaster males. In an attempt to identify the mutagenic activity of pesticides that are toxic in low concentrations in Drosophila, these males were mated with mus‐302 repair‐defective females. The rationale for this mating scheme is based on the repair of genetic damage in Drosophila sperm by maternal enzymes in the zygote, and on the reports that there may be increases in the frequency of recovery of chemically induced chromosome losses in crosses of treated males with mus‐302 females. Verification of the sensitivity of this screen in this study came from significant increases in the frequency of chromosome loss induced by low concentrations of the positive controls. N‐nitrosodimethylamine and methyl methanesulfonate. Of the 13 pesticides, the insecticide chlorpyrifos induced a significant amount of ring‐X chromosome loss. No pesticide induced a significant increase in partial chromosome loss. These results are discussed in relation to the usefulness of repair‐defective mutants in screens for genetic damage in Drosophila and other higher eukaryotes by chemicals that are toxic or cause sterility at low concentrations.
Nondisjunction induced in mouse spermatogenesis by chloral hydrate, a metabolite of trichloroethylene
Authors: Russo Antonella , Pacchierotti Francesca , Metalli Pietro 
Published: February 2007

AbstractThe effects of chloral hydrate (CH), an in vivo metabolite of trichloroethylene, have been evaluated by cytogenetic observations of mouse secondary spermatocytes after ip treatment with 82.7, 165.4, or 413.5 mg/kg bw. Hyper‐haploid metaphases have been scored to determine whether previous observations in various nonmammalian organisms about an effect of this drug on the mitotic spindle could be confirmed in mice.At each dose, the frequencies of hyper‐haploid cells have been estimated to assess the response of pachytene, preleptotene, premeiotic, and staminal gonial cells. Significant increases above the control value have been observed particularly after treatment of actively dividing gonial cells, confirming the results obtained with the same batch of the drug in a parallel collaborative investigation with Aspergillus nidulans.Thus: a) chloral hydrate has been shown to be effective in inducing nondisjunction in a mammalian system; b) a prevalent action on the mitotic spindle has been confirmed and quantified; and c) the usefulness of parallel investigations with different methods is stressed, particularly to collect information about the mechanisms of induction of nondisjunction events.
Structural features of nitroaromatics that determine mutagenic activity in salmonella typhimurium
Authors: Vance William A. , Levin David E. 
Published: February 2007

AbstractSeventeen structurally homologous nitroaromatics were tested for direct‐acting mutagenic potency in nine strains of Salmonella typhimurium. The following four structural features were determined to have a strong influence on mutagenic activity: physical dimensions of the aromatic rings, isomeric position of the nitro group, conformation of the nitro group with respect to the plane of the aromatic rings, and ability to resonance‐stabilize the ultimate electrophile. Progressive addition of five‐ and six‐membered rings to a nitrobenzene nucleus demonstrated that mutagenic activity was a direct function of size. Fluoranthene was of optimal size (four rings) for mutagenicity; an additional benzene ring, giving benzo[k]fluoranthene, reduced mutagenic activity. Nitroaromatics with a nitro group oriented along the long axis of symmetry of the molecule were more potent mutagens than those with the nitro group oriented along the short axis. These results are discussed in light of the insertion‐denaturation model for intercalation of certain DNA adducts. Nitroaromatics with nitro groups sterically forced out of the plane of the aromatic rings were weakly mutagenic or nonmutagenic. Nitro groups located between two peri hydrogens or in a bay‐region are examples of this conformation. Finally, structural features that contribute to resonance stabilization of the reactive nitrenium ion enhance mutagenic potency. Thus, 6‐nitroindene was at least tenfold more mutagenic than 5‐nitroindene. These positional isomers are structurally identical with the exception of the position of an olefinic bond in the adjacent five‐membered ring which can contribute to resonance stabilization of a carbonium ion formed after bioactivation of 6‐nitroindene but not of 5‐nitroindene. The predictive value of these structure‐activity relationships should permit a first approximation in the assessment of mutagenic potency of nitroaromatics.
Review: Putative mutagens and carcinogens in foods. VI. Protein pyrolysate products
Authors: Vuolo Loretta L. , Schuessler Glenn J. 
Published: February 2007

AbstractDiet and nutrition may be responsible for 60% of the total cancer incidence for women and greater than 40% for men. Fat, animal protein, and meat consumption are highly correlated with colon cancer incidence. The charcoal broiling of meat and fish yield mutagenic substances. Many findings support the hypothesis that the predominant mutagens are formed by the Maillard reaction. A number of mutagenic compounds have been identified both from cooked foods and from protein pyrolysates. The identified compounds are N‐heterocyclic primary amine derivatives of either carbolines, imidazoquinolines, or imidazoquinoxalines. The carboline‐type mutagens are structurally related to the known carcinogens 2‐acetylaminofluorene (AAF) and 2‐aminofluorene (AF), while the imidazoquinoline and imidazoquinoxaline types are believed to resemble 3,2′‐dimethyl‐4‐aminobiphenyl (DMAB). Studies support the theory that these compounds require metabolic activation and are carcinogenic. The major metabolites of several compounds have been identified as the N‐hydroxy derivatives. DNA binding was found to be a necessary but not a sufficient condition for mutagenesis. The modified base products have been identified as C‐8‐guanyl derivatives, resembling adducts formed by the carcinogenic aromatic amines.
Metabolism and mutagenicity of acrylonitrile: An in vivo study
Authors: Lambotte‐Vandepaer M. , Duverger‐van Bogaert M. , Rollmann B. 
Published: February 2007

AbstractThe mutagenic activity present in urine of animals treated with acrylonitrile (ACN) is tentatively related to the excretion of three urinary metabolites: thiocyanate (SCN−), hydroxyethylmercapturic acid (OH‐MA), and cyanoethylmercapturic acid (CN‐MA). It is shown that the route of administration and animal species affect SCN− excretion but not the excretion of hydroxyethyl‐ and cyanoethylmercapturic acids or the mutagenicity of urine from ACN‐treated animals. Various pretreatments (phenobarbital, CoCl2, diethylmaleate, trichloroacetonitrile) decrease the mutagenicity of urine from ACN‐treated animals and decrease the excretion of SCN− and OH‐MA. None of the quantified urinary metabolites is responsible for urinary mutagenicity.
Measurement of unscheduled DNA synthesis in rat kidney cells following in vivo treatment with genotoxic agents
Authors: Tyson C. Kimerly , Mirsalis Jon C. 
Published: February 2007

AbstractThe kidney is a key target tissue in animal and human carcinogenesis, yet there are no established short‐term tests for studying the genotoxicity of chemicals in the kidney. We have developed an assay for the measurement of chemically induced DNA repair as unscheduled DNA synthesis (UDS) in isolated rat kidney cells following in vivo treatment. Male Fischer‐344 rats were injected intraperitoneally with chemicals dissolved in saline or corn oil. After various treatment times, the kidneys were perfused with a collagenase/trypsin solution (CTS), minced into small pieces, and stirred in CTS at 37°C for 1 hr to dissociate cells. Cultures contain a high proportion of epithelial cells from the proximal and distal tubules. Cultures were incubated for 16–18 hr with 3H‐thymidine in Williams' Medium E supplemented with 20% fetal bovine serum. UDS was measured by quantitative autoradiography as net grains/nucleus (NG). The percentage of cells in repair (% IR) was defined as the percentage of cells with ⩾ 3 NG. Saline‐ or corn oil‐injected controls consistently produced −3 to −5 NG with < 1 % IR. The time course of DNA repair following treatment with the direct‐acting mutagen methylmethane sulfonate (MMS) or the renal carcinogen azaserine showed a peak response at 2 hr after treatment. Azaserine showed a rapid decline in UDS at 12 and 24 hr, whereas MMS exhibited a relatively high UDS level at 24 hr. The renal carcinogens methylazoxymethanol acetate, N‐methyl‐N‐nitrosourea, and streptozotocin all yielded strong positive UDS responses. The liver and intestinal carcinogen 1, 1‐dimethylhydrazine at doses up to 50 mg/kg was cytotoxic to kidney cells, but induced < 0 NG. Treatment with 1,2‐dimethylhydrazine, which induces kidney tumors in mice but not rats, also induced < 0 NG. Treatment with o‐anisidine, a weak renal carcinogen, did not induce UDS in the kidney, suggesting that it may be acting as a tumor promotor. These results demonstrate the usefulness of this assay for the detection and study of a variety of genotoxic kidney carcinogens.
Strategies to reduce the cost of mutagenicity screening with the Salmonella assay
Authors: Zeiger Errol , Risko Kenneth J. , Margolin Barry H. 
Published: February 2007

AbstractAn extensive Salmonella assay database was analyzed in order to develop strategies to reduce costs of screening chemicals for mutagenicity. This database was obtained from testing 941 samples (representing 799 chemicals), 36% of which were judged mutagenic. Strains TA98, TA100, TA1535, and TA1537 without activation, with rat liver S‐9, and with hamster liver S‐9, make up the 12 strain/ activation combinations considered here. The testing strategies examined consist of two or three stages; a positive result at any stage is regarded as definitive and stops the testing. Sequential testing improves efficiency by eliminating the need for further experimentation once a chemical has been found to be mutagenic. Consequently, costs and effort are reduced. For screening chemicals in the Salmonella assay, it is our recommendation that a sequential testing scheme be adopted whose initial stage consists of TA 100.
Micronuclei in red blood cells of the newt pleurodeles waltl after treatment with benzo(a)pyrene: Dependence on dose, length of exposure, posttreatment time, and uptake of the drug
Authors: Grinfeld S. , Jaylet A. , Siboulet R. , Deparis P. , Chouroulinkov I. 
Published: February 2007

AbstractAquatic larvae of the newt Pleurodeles waltl were exposed to different concentrations of benzo(a)pyrene (BaP) for various lengths of time. Frequencies of micronuclei in circulating erythrocytes were determined at different times after termination of the treatment. The incidence of micronuclei in larvae kept for 8 days in BaP‐containing water displayed a marked increase with dose up to 0.075 ppm and a more gradual one with higher doses, reaching 158 per 1,000 at 0.75 ppm. The lowest dose at which a significant increase could be discerned was 0.01 ppm. Short periods of exposure, less than 2 days, did not result in a marked increase in micronuclei. Uptake and release was studied with tritiated BaP. Larvae concentrated BaP rapidly, attaining maximal levels after 12 hr. The ratio of radioactivity in larvae to that in an equivalent volume of surrounding water was about 200 independent of the amount of BaP added. Calf serum or bovine serum albumin added to the water lowered this ratio by competing for binding to BaP. Radioactive larvae placed in regularly renewed noncontaminated water lost 99% of the label after 100 hr. It is concluded that pleurodele larvae are a promising model for the detection of genotoxic activity in the aquatic environment.
Electronic considerations in the mutagenesis of some 4,5‐bridged chrysenes
Authors: Lee‐Ruff E. , Raj A. S. , Kruk H. , Katz M. 
Published: February 2007

AbstractThe mutagenic activity of four 4,5‐bridged chrysene derivatives, benz(a)aceanthrylene, and 5‐methylchrysene was examined using histidine auxotrophic strains TA98 and TA100 of Salmonella typhimurium. All compounds showed a positive mutagenic response with both TA100 and TA98 in the presence of S‐9. A correlation between the electronic character of the bridging group and mutagenic activity for the chrysene derivatives is proposed.
Skin‐graft reconstruction in carcinoma of the tongue
Authors: McGregor Ian A. , McGrouther Duncan A. 
Published: February 2007

AbstractThe use of quilted grafts in the treatment of minimally infiltrative carcinoma of the tongue is described. Results are assessed in terms of therapeutic effectiveness and functional adequacy. This single‐stage graft procedure is compared to multistage flap reconstruction as well as to direct suture. We conclude that, with careful selection of patients, the method is a satisfactory one.
Permanent control of massive tumor bleeding with intraluminal balloon catheters
Authors: Prian Gregory W. , Pearlman N. W. 
Published: February 2007

AbstractProximal ligation usually controls bleeding from a tumor‐eroded carotid artery. When this maneuver failed, two intraluminal balloon catheters were passed distally into the vessel, after which they were inflated and left in place for six weeks. The patient had no neurologic sequelae or further bleeding before succumbing to tumor progression 10 months later.
The suboccipital approach to removal of acoustic neuromas
Authors: Rhoton Albert L. 
Published: February 2007

AbstractThis article reviews the author's technique for removing acoustic neuromas by the suboccipital approach. Also discussed are various considerations regarding the selection and use of instruments for this operation. The anatomy of the internal acoustic meatus and the principles involved in facial‐ and cochlear‐nerve preservation are described. A guide is provided for stepwise dissection of the internal acoustic meatus in the laboratory.
Therapeutic embolization of the carotid arteries: A review
Authors: Moseley Ivan 
Published: February 2007

AbstractTherapeutic embolization is now used widely for the treatment, either definitive or preoperative, of vascular lesions within areas supplied by the carotid arteries. Its place in the treatment of arteriovenous fistulas, malformations, and vascular tumors fed largely by the external carotid artery is established, although some of the newer embolic materials have not been fully proven. Balloon catheters appear to represent an important method for treating internal carotidcavernous sinus and similar fistulas. Embolization of cerebral lesions is still practiced on a much smaller scale, and questions as to its efficacy and safety have not been resoived.
Embolization techniques in vascular tumors of the head and neck
Authors: Thompson James N. , Fierstein Stephen B. , Kohut Robert I. 
Published: February 2007

AbstractSurgical excisions of vascular tumors of the head and neck are frequently associated with difficulties because of the potential of operative blood loss. The technique of selective percutaneous embolization before surgery has emerged as a valuable adjunct—and even alternative—to surgery in the management of such lesions. By reducing the blood flow to a vascular tumor or arteriovenous malformation, embolization techniques can greatly facilitate surgical excision. The participation of a qualified invasive radiologist is essential. If cases are carefully selected and procedural details strictly adhered to, this technique can be quite valuable to surgeons treating vascular lesions of the head and neck.
Value and limits of computer‐assisted tomography
Authors: Schindler Erwin , Reck Ralf 
Published: February 2007

AbstractThree years ago, at the VIIth International Congress of Radiology in Otorhinolaryngology, held in Copenhagen, the early impressive results of computer‐assisted tomography (CAT) in otorhinolaryngology were presented. Since considerable technologic and diagnostic progress of CAT has taken place in the meantime, questions about the increase in CAT's value and the expansion of its limits are appropriate now. Computed and, in some cases, conventional tomograms of facial lesions are used in the discussion of these questions. There is no doubt of CAT's advance within the last few years; there are, however, limits of CAT to be emphasized: (a) coronal CAT might be uncomfortable (especially if the gantry cannot be tilted), unsuccessful (e.g., in cases of neck stiffness), and even dangerous (when head injury is combined with trauma to the cervical spine); (b) enhancement is often not useful (except when intracranial tumor invasion is suspected); (c) specific diagnosis, based on CAT findings only, is impossible in most cases; (d) the radiation dose, which increases with improvement in the quality of the image, must be considered in each case; and (e) CAT does not replace conventional x‐ray techniques, least of all polytomography.
Computer‐assisted tomography: Sinus lesions with orbital involvement
Authors: Bilaniuk Larissa T. , Zimmerman Robert A. 
Published: February 2007

AbstractComputer‐assisted tomography (CAT) is superior to other roentgenographic modalities in evaluation of paranasal sinus lesions whenever extension into the orbit is suspected. CAT not only demonstrates the orbital involvement, its location, and extent, but also the nature of the sinus lesion. Conclusions based on 43 cases of paranasal sinus lesions with orbital involvement are presented. The entities include sinusitis with orbital cellulitis, mucocele, polyposis, ossifying fibroma, fibrous dysplasia, cylindroma, osteoblastoma, lymphoma, carcinoma, and rhabdomyosarcoma.
Bilateral Z‐flap pharyngoplasty in the treatment of rhinolalia
Authors: Meyer Rodolphe , Failat Abdul S. Abul , Kelly Thomas P. 
Published: February 2007

AbstractA technique using a bilateral Z‐flap pharyngoplasty in the treatment of rhinolalia is reviewed. Also reviewed is the historical development of the surgical treatment of rhinolalia. Sixteen patients with rhinolalia and 3 patients with pharyngitis sicca who were treated by this technique have been followed for up to 16 years, and have shown marked improvement in speech.
Experiences with the deltopectoral flap in reconstructive surgery of the head and neck
Authors: Tiwari Ram M. , Gorter H. , Snow Gordon B. 
Published: February 2007

AbstractDespite the development of many alternative methods of reconstruction in head and neck surgery, the deltopectoral skin flap still remains a useful method in our armamentarium. Its use as a nondelayed procedure in 44 patients with various defects in the head and neck following tumor surgery is discussed. The reliability of the deltopectoral flap is evaluated. Major necrosis of the flap occurred in 6 (13.6%) of our patients. As to the cause of failure, more than one factor could be identified in the individual patient. However, the failure rate was higher when the flap was used in the reconstruction of defects in the anterior part of the oral cavity, particularly the floor of the mouth, than at other sites in the head and neck.
Surgical management of carcinoma of the posterior pharyngeal wall
Authors: McNeill Roger 
Published: February 2007

AbstractCarcinoma of the posterior pharyngeal wall is an aggressive disease that demands vigorous therapy, often in the form of combined surgery and radiotherapy. Surgical excision of wide areas of the posterior pharyngeal wall may allow acceptable swallowing function in many patients. This article reviews the methods of surgical exposure utilized in conservation pharyngeal surgery and emphasizes the important principles involved in the preservation of laryngeal and pharyngeal functions.
Advances in head and neck surgery in children
Authors: Cotton Robin T. , Richardson Mark A. 
Published: February 2007

AbstractAdvances in pediatric head and neck surgery in the past decade have been on broad fronts. The laser coupled with the microscope has become an invaluable tool in the management of laryngeal pathologic entities such as papilloma, cysts, hemangiomas, and granulation tissue secondary to endotracheal tube damage. Its use in the management of choanal stenosis is increasing. Improvements in radiation and combination chemotherapy have spectacularly increased the survival rates in rhabdomyosarcoma. Newer surgical procedures for correction of drooling are obtaining good results. Reconstructions of extensive laryngotracheal stenoses in children are being performed with considerable success. Better techniques are available for revision surgery of defects remaining after primary palatoplasty.