bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular analysis of formaldehyde‐induced mutations in human lymphoblasts and e. coli
Authors: Crosby R. M. , Richardson K. K. , Craft T. R. , Benforado K. B. , Liber H. L , Skopek T. R. 
Published: February 2007

AbstractThe molecular nature of formaldehyde (HCHO)‐induced mutations was studied in both human lymphoblasts and E. coli. Thirty HPRT− human lymphoblast colonies induced by eight repetitive 150 μM HCHO treatments were characterized by Southern blot analysis. Fourteen of these mutants (47%) had visible deletions of some or all of the X‐linked HPRT bands, indicating that HCHO can induce large losses of DNA in human lymphoblasts. In E. coli, DNA alterations induced by HCHO were characterized with use of the xanthine guanine phosphoribosyl transferase (gpt) gene as the genetic target. Exposure of E. coli to 4 mM HCHO for 1 hr induced large insertions (41%), large deletions (18%), and point mutations (41%). Dideoxy DNA sequencing revealed that most of the point mutations were trans versions at GC base pairs. In contrast, exposure of E. coli to 40 mM HCHO for 1 hr produced 92% point mutations, 62% of which were transitions at a single AT base pair in the gene. Therefore, HCHO is capable of producing different genetic alterations in E. coli at different concentrations, suggesting fundamental differences in the mutagenic mechanisms operating at the two concentrations used. Naked pSV2gpt plasmid DNA was exposed to 3.3 or 10 mM HCHO and transformed into E. coli. Most of the resulting mutations were frameshifts, again suggesting a different mutagenic mechanism.
Molecular analyses of in vivo hypoxanthine‐guanine phosphoribosyltransferase mutations in human T‐lymphocytes: II. Demonstration of a clonal amplification of hprt mutant T‐lymphocytes in vivo
Authors: Nicklas J. A. , O'Neill J. P. , Sullivan L. M. , Hunter T. C. , Allegretta M. , Chastenay B. F. , Libbus B. L. , Albertini R. J. 
Published: February 2007

AbstractRecent molecular analysis of in vivo‐derived hprt mutant T‐lymphocytes cloned from human blood show that mutants occurring at the normal frequency (˜ 5 × 10−6) in healthy young individuals generally represent independent hprt mutations. Here we report that in an individual with a high mutant frequency (86–620 × 10−6),92% (61/66) of the mutant clones are descendents of an original mature T‐cell precursor that has undergone in vivo clonal expansion. Therefore, these mutants could represent as few as one original hprt mutation. If so, correcting for the clonal expansion yields a revised calculated mutant frequency (Mf) value for this individual that is near the normal range. These hprt mutant clones all showed identically rearranged T‐cell receptor (TCR) β and γ gene patterns by Southern blot analysis. All the clones were surface marker CD4+, showed no obvious chromosomal aberration, and had no detectable hprt gene structural alteration. This TCR‐defined T‐cell clone appears to have expanded in the blood of the individual over a 6‐month period and persists at high levels after nearly 4 years.This finding illustrates the need to analyze mutants from individuals with high mutant frequencies at the molecular level in order to estimate hprt mutation frequency from the calculated hprt mutant frequency. The possibility that spontaneous hprt mutants might arise in vivo preferentially in dividing cells, and implications of this, are discussed.
Use of seminiferous tubule segments to study stage specificity of unscheduled dna synthesis in rat spermatogenic cells
Authors: Bentley Karin S. , Working Peter K. 
Published: February 2007

AbstractDNA repair in spermatogenic cells at various stages of maturity was determined by quantitation of unscheduled DNA synthesis (UDS). Male F‐344 rats were exposed (i.p.) to methyl methanesulfonate (MMS, 35 mg/kg); 1 hr later, segments of seminiferous tubules corresponding to spermatogenesis stages II, IV‐V, VI, VII, VIII, IX‐X, XII, and XIV were isolated with the transillumination pattern of the tubules as a guide. Intact tubule segments were cultured 24 hr in the presence of [3H]thymidine, and UDS was quantitated by autoradiography as net grains/nucleus (NG). In primary spermatocytes from treated rats, NG count increased with increasing maturity from leptotene primary spermatocytes (3.5 NG) up through stage VIII and IX‐X pachytene spermatocytes (22 NG), after which NG decreased in stage‐XII pachytene and diplotene spermatocytes (to 16 NG and 8 NG, respectively). Round spermatids of steps 2‐8 of spermiogenesis all exhibited approximately the same UDS response (8 NG). Elongating spermatids as mature as step 14 underwent UDS after exposure to MMS, but step‐15 and later‐step spermatids did not. The DNA repair response of pachytene spermatocytes cultured within segments of seminiferous tubule corresponding to stages VIII and IX‐X was 4 to 25 times greater, depending on the dose of MMS, man pachytene spermatocytes isolated by enzymatic digestion and cultured in suspension [Bentley and Working, Mutat Res 203:135‐142, 1988]. Thus, the use of segments of seminiferous tubule both increased the sensitivity of UDS as an indicator of DNA damage in rat germ cells and enabled the study of UDS in spermatogenic cells at different stages of maturity.
Persistence of micronuclei in peripheral blood normochromatic erythrocytes of subchronically benzene‐treated male mice
Authors: Rithidech Kanokporn , Au William W. , Ramanujam V. M. Sadagopa , Whorton Elbert B. , Legator Marvin S. 
Published: February 2007

AbstractThe kinetics of micronucleus (MN) induction and decline in blood normochromatic erythrocytes (NCE) of mice subchronically exposed to benzene was investigated during and after exposure. Swiss (ICR) male mice (10/group) were given 0.0, 36.6, 73.2, and 146.4 mg/kg body weight benzene by gavage daily for 14 days, except for days 5 and 10. The frequency of MN increased significantly (P <.001) during benzene treatment as a function of both concentration and time. Eleven days after exposure the levels of MN were higher than those observed at the end of exposure. After an initial rapid decline in the frequency of MN from 11 to 18 days postexposure, the decline became linear with time through 60 days postexposure. Using linear regression analysis, the MN level in each treatment group was predicted to reach control levels by approximately 85 days post‐treatment. Dose‐dependent suppression and recovery of erythropoiesis, estimated by polychromatic erythrocyte frequency, were observed in the 1st and 2nd weeks of exposure, respectively. Red blood cell (RBC) production was markedly increased in the first 3 weeks after benzene treatment. At later times the rate of production of the RBC returned to normal and may account for the linear decline observed in MN frequency. This research indicates that the frequency of MN is dose and duration dependent, while the decline in MN frequency after the end of benzene exposure can be related to changes in the kinetics of erythropoiesis.
Mutagenicity to bacteria, cultured cells, and rodents of the human carcinogen chlornaphazine
Authors: Ashby J. , Loquet C. , Ishidate M. , Callander R. D. , Albanese R. 
Published: February 2007

AbstractThe human carcinogen and nitrogen mustard chlornaphazine (CN) has been confirmed to be mutagenic to Salmonella and, unexpectedly, the more so when evaluated in the presence of liver S9 mix. It also has been established as clastogenic to Chinese hamster lung cells exposed in vitro to dose levels > 2.5 μg/ml. Chlornaphazine subdued mice at doses of 5 g/kg, but only the occasional death occurred during the 4 days following oral administration of this dose in com oil. Consequently, a median lethal dose level was not established. Nonetheless, dose levels of 500 mg/kg or greater gave a clear positive response in both the mouse and the rat bone marrow micronucleus assay. Although depression of erythropoeisis was observed in mice, a clastogenic response still was observed in the bone marrow 24 hr after dosing. The positive response in the rat was greater than that observed in the mouse. The present data provide a further instance of an established human carcinogen being readily detected by standard in vitro and in vivo mutagenicity assays.
Molecular characterization of the human common fragile site FRA1H
Authors: Curatolo Angela , Limongi Zaira M. , Pelliccia Franca , Rocchi Angela 
Published: February 2007

AbstractThe molecular basis of the fragility of common fragile sites (CFS) and their role in chromosome instability and in altered expression of associated genes in cancer cells have not yet been clarified. In the present work we analyzed the human CFS FRA1H. FRA1H is the first characterized CFS the expression of which is not induced by aphidicolin but instead by DAPI. 5‐azaC, 5‐azadC, and Ad12 induce a CFS with the same cytogenetic location. By using FISH analysis with BAC clones, we determined that this CFS extends for approximately 10 Mb, and is therefore one of the largest characterized CFSs. FRA1H maps to the chromosome bands 1q41 and 1q42.1 thus spanning an R‐band/G‐band boundary, a region considered difficult to duplicate. The FRA1H DNA sequence was analyzed to identify coding sequences, the AT content, the type and quantity of the DNA repeats, the CpG islands, the matrix attachment regions, and the number and distribution of high‐flexibility regions. A 120 kb long sequence was identified that is very AT‐rich (64.6%), has a very large number of flexibility peaks and that may be involved in inducing fragility in the surrounding regions. Among the other genes, two very large genes (USH2A, ESRRG) and two microRNA genes (MIRN194‐1, MIRN215) map within the fragile region. © 2007 Wiley‐Liss, Inc.
Association of human leukocyte antigen ancestral haplotype 8.1 with adverse outcome of non‐Hodgkin's lymphoma
Authors: Nowak Jacek , Kalinka‐Warzocha Ewa , Juszczynski Przemyslaw , Bilinski Przemyslaw , Mika‐Witkowska Renata , Zajko Malgorzata , Bienvenu Jacques , Coiffier Bertrand , Salles Gilles , Warzocha Krzysztof 
Published: February 2007

AbstractPrevious reports have implicated the tumor necrosis factor (TNF−308) locus to non‐Hodgkin's lymphoma (NHL) outcome. The purpose of the study was to examine other chromosome components of the HLA 8.1 ancestral haplotype (AH) and their relation to the clinical course of NHL. HLA class I, II, TNF−308, and lymphotoxin alpha (LTA+252) alleles were analyzed in 154 newly diagnosed NHL patients. Three locus haplotypes were inferred from the unphased genotypes by a Bayesian implementation of the expectation maximization (EM) algorithm using the PHASE 2.1 program. TNF−308A was the only allele associated with fever, poor performance status, elevated β2‐microglobulin, TNF and its p75 receptor plasma levels. Although TNF−308A was in strong linkage disequilibrium with the remaining alleles of 8.1 AH, only HLA‐A*01 and HLA‐B*08 showed association with prognostic variables. A part of 8.1 AH (A*01‐B*08‐TNF−308A) was predictive for shorter freedom from progression and overall survival (RR = 2.47, P = 0.041; RR = 3.15; P = 0.0049), an association that was stronger than TNF−308A alone and independent from International Prognostic Index (RR = 1.55, P < 0.001; RR = 2.36; P < 0.0001). A*01‐B*08‐TNF−308A fragment of 8.1AH remained an independent predictive factor in a multivariate model. We conclude that 8.1 AH is an important contributor to NHL outcome. In contrast to A*01‐B*08‐TNF−308A, the remaining alleles (Cw*07, DRB1*03, LTA+252G) associated with the 8.1 AH seem to be its passive components. © 2007 Wiley‐Liss, Inc.
DNA sequence of the translocation breakpoints in undifferentiated embryonal sarcoma arising in mesenchymal hamartoma of the liver harboring the t(11;19)(q11;q13.4) translocation
Authors: Rajaram Veena , Knezevich Stevan , Bove Kevin E. , Perry Arie , Pfeifer John D. 
Published: February 2007

AbstractUndifferentiated embryonal sarcoma of the liver is a highly malignant and aggressive tumor that occasionally arises within mesenchymal hamartoma of the liver (MHL), a benign tumor that typically occurs in young children. Undifferentiated embryonal sarcoma arising in MHL, as well as uncomplicated MHL, frequently harbor rearrangements of band 19q13.4, including the translocation t(11;19)(q13;q13.4). In this study we report the cloning and DNA sequence analysis of the translocation breakpoints in an undifferentiated embryonal sarcoma arising in MHL known to harbor t(11;19). In this case, the breakpoint at 11q13 occurred in the MALAT1 gene, also known as ALPHA. MALAT1 is rearranged in renal tumors harboring the t(6;11)(p21;q13) translocation, and noncoding MALAT1 transcripts are overexpressed in a number of human carcinomas. The breakpoint at 19q13.4 occurs at a locus we refer to as MHLB1, for Mesenchymal Hamartoma of the Liver Breakpoint 1. Although the MHLB1 locus does not contain a known gene, several human ESTs map to the region (a subset of which show homology to the nuclear RNA export factor (NXF) gene family), and the region is conserved between many mammalian species. © 2007 Wiley‐Liss, Inc.
Deliberate self‐harm in older adults: a review of the literature from 1995 to 2004
Authors: Chan Jenifer , Draper Brian , Banerjee Sube 
Published: February 2007

AbstractBackgroundThe prevention of suicide is a national and international policy priority. Old age is an important predictor of completed suicide. Suicide rates in old age differ markedly from country to country but there is a general trend towards increasing rates with increasing age. In 1996 Draper reviewed critically the evidence on attempted suicide in old age in the 10 years between 1985 and 1994. The review highlighted a need for prospective controlled studies in older people with more representative samples as well as studies examining the interaction of risk factors, precipitants, motivations, psychopathology and response to treatment. The aim of this paper is to update this review and to summarise the advances in our understanding of DSH in later life.MethodWe have critically reviewed relevant studies published between 1995 and 2004 to summarise the advances in our understanding of factors associated with deliberate self‐harm in later life.ResultsThe main advances in understanding have been to clarify the effect of personality and cultural factors, service utilisation pre and post attempt, and the (lesser) impact of socio‐economic status and physical illness. Methodological weaknesses continue to include inadequate sample sizes performed on highly selected populations, inconsistent age criteria and lack of informant data on studies relating to role of personality.ConclusionsFuture studies should include prospective, cross‐cultural research with adequate sample sizes and which are population‐based. Such approaches might confirm or refute the results generated to date and improve knowledge on factors such as the biological correlates of deliberate self‐harm, service utilisation, costs and barriers to health care, and the interaction of these factors. Intervention studies to elucidate the impact of modifying these factors and of specific treatment packages are also needed. Copyright © 2007 John Wiley & Sons, Ltd.
The surgical treatment of extratemporal facial paralysis: An overview
Authors: Conley John , Baker Daniel C. 
Published: February 2007

AbstractAt present there is no single surgical approach that is ideally suited to rehabilitation of the paralyzed face. Dynamic reconstruction and neural reconstitution are usually preferred to static methods, except under special circumstances. Experience with over 150 autogenous facialnerve grafts using epineural suture technique has resulted in return of movement in 95% of properly selected patients. When grafting is not feasible, as in the obliterated central facial nerve, hypoglossal–facialnerve crossover is a simple and powerful source of reinnervation, usually resulting in minimal intraoral crippling and mild mass movement. A newer procedure, the cross‐face nerve graft, is an alternative to hypoglossal crossover, although it results in less axonal input and longer regenerative time. In cases of long‐standing facial paralysis with muscle atrophy, temporalis and masseter transfers are dependable and may sometimes be combined with a nerve graft.
Squamous cell carcinoma of the pyriform sinus
Authors: Razack Mohamed S. , Sako Kumao , Kalnins Inars 
Published: February 2007

AbstractAt the Roswell Park Memorial Institute, 111 patients were treated for squamous cell carcinoma of the pyriform sinus over a 15‐year period. Treatment modalities included surgery, radiation therapy, or a combination of both. A retrospective study was carried out to determine how these treatments, used singly or in combination, affected the cure rate. TNM clinical staging and recurrence patterns were studied, and a high tendency for distant metastases was documented. The five‐year survival figure in this study was 29% (28/97).
Dysmorphology: An approach to diagnosing children with structural defects of the head and neck
Authors: Jones Kenneth Lyons , Higginbottom Marilyn C. 
Published: February 2007

AbstractIn dealing with a child with a structural defect, an overall diagnosis must be formulated. Such a diagnosis makes it possible to provide genetic counseling for the parents and an accurate prediction relative to such a child's future development. Because there are a great many abnormalities involving the head and neck, it is hoped that the approach set forth in this article will allow for a systematic narrowing of the diagnostic possibilities. Nomenclature is established. Prenatal‐onset defects are described, including both single primary defects (malformations and deformations) and multiple malformation syndromes (chromosomal abnormalities, genetic disorders, defects resulting from teratogenic factors, and disorders of unknown etiology). Genetic and environmental factors of postnatal developmental problems are also discussed.
Chemotherapy of head and neck cancer
Authors: Green Mark R. 
Published: February 2007

AbstractChemotherapy has traditionally been relegated to a late palliative role in the management of head and neck cancer. For advanced disease in patients previously treated with surgery or radiation therapy, methotrexate, which has a response rate of approximately 50%, is the best single agent available. Other orally or systemically administered single agents–such as bleomycin, adriamycin, hydroxyurea, and cis‐platinum–produce responses less frequently than methotrexate. Intraarterial chemotherapy with single‐agent methotrexate or with combinations– including methotrexate, vinblastine sulfate (Velban), cyclophosphamide (Cytoxan), and 5‐fluorouracil (5FU)–can match the response rate of systemic methotrexate, but all require inpatient treatment and significant technical expertise. Programs utilizing chemotherapeutic combinations have not produced remission rates or durations of remission greater than those achieved with methotrexate alone. Chemotherapy has also been used in combination with other modalities. In two studies, chemotherapy combined with irradiation produced improvement in median or overall survival in comparison to irradiation alone. Many similar studies have been negative. Recent trials of chemotherapy used preoperatively in the treatment of head and neck cancer have not yielded decreased recurrence rates or increased overall survival rates in comparison to surgery alone, but they do appear to have prolonged the diseasefree interval following definitive surgery.
The significance of “positive” margins in surgically resected epidermoid carcinomas
Authors: Looser Kevin G. , Shah Jatin P. , Strong Elliot W. 
Published: February 2007

AbstractSixty‐two patients with epidermoid carcinomas of the head and neck (excluding glottic larynx and skin), in whom surgical‐resection margins were classified as “positive,” were studied to determine the incidence of local recurrence, the subsequent clinical course, and survival. The recurrence rate in this group was compared with that of patients who had “negative” margins. Four histologic findings are classified as positive margins: (1) margin closeness (tumor within 0.5 cm), (2) premalignant change in the margin, (3) in‐situ cancer in the margin, and (4) invasive microscopic cancer at the margin. Patients with these variants showed a significant increase in local recurrence and in mortality when compared to those with negative margins. A review of the literature is presented, and recommendations are made for this clinical setting.
The pathology of head and neck tumors: Salivary glands, part 2
Authors: Batsakis John G. , Chinn Edwin , Regezi Joseph A. , Repola David A. 
Published: February 2007

AbstractAcinic‐cell carcinomas and mucoepidermoid carcinomas remain somewhat controversial salivarygland lesions. Because of an ambiguity in the literature conceming their malignant potential and a lack of sufficient follow‐up periods, these carcinomas have been underestimated with respect to their morbidity and lethality. The failure of histopathologic evaluation to successfully predict the subsequent biologic course of these neoplasms should not mitigate treatment. Aciniccell carcinomas are usually isomorphic neoplasms having their genesis in the neoplastic reserve cells of the terminal portions of the duct system. Mucoepidermoid carcinomas, on the other hand, may be described as forming a histologic spectrum or continuum from the most highly differentiated to the most poorly differentiated malignancy. They arise from the interlobular and intralobular ducts. The histopathologic features of these two neoplasms are presented, along with a review of their biologic activity in humans.
Repair of the bilateral cleft lip: A personal approach
Authors: Pitanguy Ivo 
Published: February 2007

AbstractThe author presents his personal method of repairing a bilateral cleft lip, focusing on both the embryogenic factors of this condition and its anatomicfunctional abnormalities. The surgical technique used enables correction in a single operation through suture of the lateral portions at the midline and elevation of the bifurcated flap of the prolabium to form the columella and the nasal floor. The deep psychological, social, and economic impact of the pathology is discussed, and the importance of a one‐step surgical correction of the defect for the particular patient population at question is stressed.
Rhabdomyosarcoma of the head and neck: Diagnosis and management
Authors: Healy Gerald B. , Jaffe Norman , Cassady J. Robert 
Published: February 2007

AbstractRhabdomyosarcoma represents the most common soft‐tissue neoplasm of the head and neck found in children. The tumor is most commonly seen in Caucasian children under the age of 12, usually presenting as a painless mass. Distant metastases are frequently present, especially in regional lymph nodes, lung, and bone marrow. All patients suspected of having this disorder should have a thorough examination of the head and neck, as well as a complete radiographic evaluation of the primary region. Histologic diagnosis should be made as rapidly as possible. Once this has been accomplished, a thorough search for metastatic disease can be undertaken. Therapy must be individualized, and a team approach is advocated. The roles of surgery, radiation therapy, and chemotherapy are discussed. A staging system and a treatment‐therapy plan are outlined.