Attitudes about asbestos and lung cancer.
Explore the source record for details and available documents.
Asbestos↗
Biomedical subjects
R W Morgan
Publications and source records attributed to R W Morgan.
Complete nucleotide sequence of the Marek's disease virus ICP4 gene.
The Marek's disease virus (MDV) gene encoding a homologue to the ICP4 protein of herpes simplex virus has been mapped to BamHl fragment A based on the physical map of the MDV genome (Fukuchi et al., 1984). The gene lies completely within the inverted repeat flanking the unique short region of the genome. The complete nucleotide sequence of the MDV ICP4 gene has been determined. The coding region is 4245 nucleotides long and has an overall G+C content of 52%. The MDV ICP4 protein is predicted to have a structure similar to that of ICP4-like proteins of other herpesviruses in that it has five distinct regions, the second and fourth of which are highly conserved. In addition, the protein contains the characteristic run of serine residues located toward its amino terminus. The MDV ICP4 gene is expressed in MDV-infected chicken embryo fibroblasts.
Amino Acid Sequence↗
Characterization of reticuloendotheliosis virus-transformed avian T-lymphoblastoid cell lines infected with Marek's disease virus.
The expression of Marek's disease virus (MDV) transcripts and protein products was investigated in reticuloendotheliosis virus-transformed avian T-lymphoblastoid cell line RECC-CU91, which was superinfected with MDV. The presence of MDV in the superinfected cell line, renamed RECC-CU210, was demonstrated by Southern hybridization with 32P-labeled BamHI-H and -B fragments of the BamHI MDV DNA library. Examination of RECC-CU210 for the expression of MDV-specific RNA transcripts encoded by the internal repeat long (IRL), internal repeat short (IRS), and unique short (US) regions of the MDV genome revealed two small transcripts of 0.6 and 0.7 kb. These transcripts were mapped to the IRL and IRS regions, respectively. In contrast, RECC-CU211, which was developed through transfection of CU210 with the BamHI-A fragment of MDV, expressed an additional nine transcripts from the IRL, IRS, and US regions. CU211 but not CU210 also expressed a complex of polypeptides of 40, 38, and 24 kDa, identified by monoclonal antibodies as MDV-specific phosphoproteins. The 38-kDa phosphoprotein is likely to be pp38, an early viral protein that maps within the IRL region of the MDV genome. These findings suggest that genes located within the transfected BamHI-A fragment transactivated a number of genes located in the IRL region of the MDV genome.
Animals↗
Re: Meta-analysis of asbestos and gastrointestinal cancer.
Explore the source record for details and available documents.
Asbestos↗
The solvent effects of calcium hydroxide irrigating solution on bovine pulp tissue.
The solvent effects of calcium hydroxide irrigating solution (used alone and in combination with sodium hypochlorite) on bovine pulp tissue were studied. Forty pieces of pulp tissue weighing 90 mg each were treated with calcium hydroxide solution alone, calcium hydroxide and sodium hypochlorite alternated, sodium hypochlorite alone, and saline alone. Each piece of tissue was treated for 32 min. Desiccated pretreatment and posttreatment weights were compared. There was no significant difference between the dissolution capability of calcium hydroxide solution used alone and of saline. No significant difference was noted between calcium hydroxide solution and sodium hypochlorite used alternately, and sodium hypochlorite used alone. However, both of these groups were significantly more effective at dissolving tissue than calcium hydroxide solution alone or saline. Calcium hydroxide solution was an ineffective solvent of pulpal tissue. If tissue dissolution is desired during root canal therapy, the use of calcium hydroxide solution as the sole irrigant is no more effective than saline.
Analysis of Variance↗
Isolation of a Marek's disease virus (MDV) recombinant containing the lacZ gene of Escherichia coli stably inserted within the MDV US2 gene.
We have isolated a stable, recombinant Marek's disease virus (MDV) containing the lacZ gene of Escherichia coli inserted into the unique short region of the genome. The nucleotide sequence of the insertion site indicates that it lies within a sequence homologous to the US2 gene of herpes simplex virus. Stable insertion of the lacZ gene into the MDV US2 gene indicates that the site is nonessential for MDV growth in cell culture.
Amino Acid Sequence↗
Whodunit? Liability for mesothelioma cases.
It is possible to apportion blame for mesothelioma incidence to previous exposure in relation to an exponent of the time since that exposure. This article demonstrates the application of a formula to calculate the probability that a specific exposure caused an individual mesothelioma case.
Asbestosis↗
An alkyl hydroperoxide reductase from Salmonella typhimurium involved in the defense of DNA against oxidative damage. Purification and properties.
A peroxide reductase (peroxidase) which converts lipid hydroperoxides and other alkyl hydroperoxides to the corresponding alcohols, using either NADH or NADPH as the reducing agent, has been identified in both Salmonella typhimurium and Escherichia coli. This enzyme is shown to play a role in protecting against alkyl hydroperoxide mutagenesis. To our knowledge this work represents the first description of an NAD(P)H peroxidase in enteric bacteria and the first reported bacterial peroxidase to exhibit high activity toward alkyl hydroperoxides. A high performance liquid chromatography-based assay for the alkyl hydroperoxide reductase has been developed by monitoring the reduction of cumene hydroperoxide, a model alkyl hydroperoxide. By using this assay, the enzyme has been purified from a S. typhimurium regulatory mutant, oxyR1, which overexpresses a number of proteins involved in defenses against oxidative damage, and which contains 20-fold more of the alkyl hydroperoxide reductase than the wild-type strain. The purified activity requires the presence of two separable components having subunit molecular weights of 22,000 and 57,000. The 57-kDa protein contains a bound FAD cofactor and can use either NADH or NADPH as an electron donor for the direct reduction of redox dyes, or of alkyl hydroperoxides when combined with the 22-kDa protein. This enzyme may thus serve as a prokaryotic equivalent to the glutathione reductase/glutathione peroxidase system in eukaryotes.
Benzene Derivatives↗
An epidemiologic investigation of birth outcomes in relation to dibromochloropropane contamination in drinking water in Fresno County, California, USA.
This report describes an epidemiologic investigation of the relationship between dibromochloropropane (DBCP), contamination in drinking water and birth outcomes between 1978 and 1982 in Fresno County, California, USA. Census tracts in the county were categorized according to DBCP level in drinking water. A direct comparison between exposure categories was done by the use of the Mantel-Haenszel chi-square procedure to compute relative ratios or risks for low birth weight and birth defect, adjusting for age, race, percent Hispanic, and parity. No correlation between these birth outcomes and DBCP contamination was found. In addition, we did not find any difference in sex ratio in relation to DBCP contamination.
Adolescent↗
An alkyl hydroperoxide reductase induced by oxidative stress in Salmonella typhimurium and Escherichia coli: genetic characterization and cloning of ahp.
The ahp genes encoding the two proteins (F52a and C22) that make up an alkyl hydroperoxide reductase were mapped and cloned from Salmonella typhimurium and Escherichia coli. Two classes of oxidant-resistant ahp mutants which overexpress the two proteins were isolated. ahp-1 was isolated in a wild-type background and is dependent on oxyR, a positive regulator of defenses against oxidative stress. ahp-2 was isolated in an oxyR deletion background and is oxyR independent. Transposons linked to ahp-1 and ahp-2 or inserted in ahp mapped the genes to 13 min on the S. typhimurium chromosome, 59% linked to ent. Deletions of ahp obtained in both S. typhimurium and E. coli resulted in hypersensitivity to killing by cumene hydroperoxide (an alkyl hydroperoxide) and elimination of the proteins F52a and C22 from two-dimensional gels and immunoblots. ahp clones isolated from both S. typhimurium and E. coli complemented the cumene hydroperoxide sensitivity of the ahp deletion strains and restored expression of the F52a and C22 proteins. A cis-acting element required for oxyR-dependent, rpoH-independent heat shock induction of the F52a protein was present at the S. typhimurium but not the E. coli ahp locus.
Blotting, Western↗
Ecological analyses and case-control studies of gastric cancer and leukaemia in relation to DBCP in drinking water in Fresno County, California.
Through ecological analyses and case-control studies, the possible relation of gastric cancer and leukaemia to dibromochloropropane (DBCP) contamination of drinking water in Fresno County, California, has been examined. The ecological analyses examined the correlation between gastric cancer and leukaemia (including the lymphatic varieties), mortality rates, and DBCP concentrations in drinking water by census tract in Fresno County, 1960-83. No correlation was found between gastric cancer or leukaemia and DBCP. The gastric cancer case-control study consisted of 263 deaths from gastric cancer in the county, 1975 to mid-1984, and 1044 controls, using information on residential history and occupation of both cases and controls. Analyses were based on residence at death, as well as one and ten years before death. The case-control study did not find any relation between gastric cancer and DBCP in drinking water. Hispanics in the county were found to experience a relative risk of gastric cancer of 2.77, compared with non-Hispanics. A similar case-control study consisting of 259 cases of leukaemia and 1161 controls found no relation between all leukaemia or lymphatic leukaemia and DBCP in drinking water. Farm workers, however, do appear to have an increased risk of leukaemia.
Agricultural Workers' Diseases↗
An epidemiologic investigation of the relationship between DBCP contamination in drinking water and birth rates in Fresno County, California.
This report describes an epidemiologic investigation of the relationship between DBCP (dibromochloropropane) contamination in drinking water and birth rates between 1978 and 1982 in Fresno County, California. Census tracts in the county were categorized according to DBCP level in their drinking water. Standardized birth ratios and relative birth ratios (adjusted for age, race, per cent Hispanic, and parity) were calculated for these census tracts. No relation between birth ratios and DBCP contamination in drinking water was found.
Adult↗
Problems associated with collecting drinking water quality data for community studies: a case example, Fresno County, California.
This paper discusses methodology in developing exposure data for the water supply contaminant dibromochloropropane (DBCP) in Fresno County, California. There are 532 drinking water systems (49 large and 483 small) within Fresno County plus 14,000 private wells. We determined the number of wells per system, the output per well, and the population served by each system. The task of deriving water quality estimates for each census tract was complicated by the fact that a single census tract can be served by more than one system; each system usually has more than one well; and a single well can have several episodes of testing for various contaminants. We calculated a series of weighted averages for concentrations of DBCP, arsenic, and nitrates for each census tract, using water production figures for each well as the weighting factor. Water quality data were derived from a total of 14,861 laboratory reports, although the majority did not report on all contaminants. Mean DBCP levels ranged from 0.0041 ppb to 5.7543 ppb among the census tracts. We found no correlation between DBCP levels per census tract compared to either arsenic or nitrates. We believe that we made as complete an exposure assessment as practically feasible.
Arsenic↗
Functional significance of histologic alterations induced by Escherichia coli pig-specific, mouse-negative, heat-stable enterotoxin (STb).
In contrast to cholera enterotoxin and other Escherichia coli enterotoxins, a pig-specific, heat-stable E. coli enterotoxin (STb) causes morphologic lesions (loss of villous epithelial cells and partial villous atrophy). These lesions reflect a loss of absorptive cells and thus suggest that STb causes impaired absorption as well as inducing net secretion. The present studies assess functional significance of morphologic changes induced by STb. Net fluid movement, mucosal surface area, sucrase activity and the electrical response induced by alanine were measured in swine jejunal loops exposed to E. coli culture filtrates with and without STb. Net fluid secretion (-11.1 +/- 1.1 ml) occurred in some STb loops (secretors) and net absorption (2.7 +/- 0.3 ml) in others (nonsecretors), but net absorption occurred in all control loops (4.9 +/- 0.2 ml). The mucosal surface area of STb loops was about 20% less than that of controls (P less than 0.01). Sucrase activity was also lower (about 15%) in STb loops than in control loops (P less than 0.01). The electrical response induced by alanine in mucosa from nonsecreting STb loops did not differ from that induced in mucosa from control loops. However, the response to alanine in mucosa from secreting STb loops was reduced about 70% from that in mucosa from nonsecreting STb loops or from control loops (P less than 0.05). It is concluded that reduced sucrase activity is a functional correlate to villous atrophy induced by STb, that STb impairs alanine absorption in some loops (secretors), and that the impaired alanine absorption is independent of the decreased surface area caused by STb. Because the impaired alanine absorption occurred independent of the decreases in surface area, it is suggested that the secretory response to STb is associated with an impairment of active absorption of alanine.
Animals↗
Reconstructive materials for endodontically treated teeth.
A review of the literature on restoration of endodontically treated teeth was presented. The advantages and disadvantages of current methods and materials were described, and a detailed technique was suggested for the newer glass-ionomer restorative materials. An all-purpose material suited for the restoration of endodontically treated teeth is still unavailable. Each patient requires individual consideration. However, Ketac Silver material may be an excellent choice in select patients.
Cermet Cements↗
Investigation and work-up of tight building syndrome.
In recent years, incidents involving health-related complaints due to poor indoor air quality have increased dramatically. These problems have generally occurred in new or remodeled buildings. Following relocation to a new building, some employees began to experience health complaints, including upper respiratory tract irritation, headaches, fatigue, and eye irritation. A questionnaire was designed which elicited information about specific work locations, symptom experience, and timing of such symptoms. Although no causative agent(s) could be isolated, the data collected indicate that over the 5-week time period of investigation the rate and persistence of new symptoms decreased. The health complaints experienced appeared to be neither persistent nor pervasive enough to constitute an ongoing health and safety hazard at the facility. Reasons were proposed why some new and/or remodeled buildings have this type of problem while others do not.
Adult↗
Hydrogen peroxide-inducible proteins in Salmonella typhimurium overlap with heat shock and other stress proteins.
Hydrogen peroxide treatment induces the synthesis of 30 proteins in Salmonella typhimurium. Five of these proteins are also induced by heat shock, including the highly conserved DnaK protein. The induction of one of these five proteins by heat shock is dependent on oxyR, a positive regulator of hydrogen peroxide-inducible genes, while the induction of the other four by heat shock is oxyR independent. Five of the 30 hydrogen peroxide-inducible proteins have been identified, and their structural genes have been mapped. Other stresses such as nalidixic acid, ethanol, or cumene hydroperoxide treatment also induce subsets of the 30 hydrogen peroxide-inducible proteins as well as additional proteins. Hydrogen peroxide-inducible proteins are shown to be largely different from those proteins induced by aerobiosis. In addition, the expression of the katG (catalase) gene is shown to be regulated by oxyR at the level of mRNA.
Adaptation, Physiological↗
An epidemiological study of petroleum refinery employees.
A cohort study of 14179 current and former Chevron USA employees at the Richmond and El Segundo, California, refineries was conducted. The cohort consisted of everyone working at either refinery for a minimum of one year. The observed mortality of the cohort, by cause, was compared with the expected based on the United States mortality rates, standardised for age, race, sex, and calendar time. Analyses by refinery, job category, hire date, duration of employment, and latency were performed. For the entire cohort, mortality from all causes was 72.4% of that expected, a deficit that was statistically significant. In addition, a significantly lower mortality was found for all forms of cancer combined, digestive cancer, lung cancer, heart disease, non-malignant respiratory disease, diseases of the digestive system, and accidents. Only lymphopoietic cancer showed a pattern of increased risk suggestive of a possible relation to an occupational exposure. The excess appears confined to cancer of lymphatic tissue (not leukaemias) at Richmond, and only among those hired before 1948. A follow up case analysis of the deaths from lymphatic cancer failed to identify a common exposure pattern.
Brain Neoplasms↗