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T L Thomas

Publications and source records attributed to T L Thomas.

At least 73 records · Page 4Linked to original sources
PubMed1988

Site specificity of adrenalectomy-induced brain growth.

Infant, juvenile, and adult brain growth is modulated by corticosterone. This study was designed to determine whether such modulation is confined to certain specific brain areas, and if the pattern of growth revealed is consistent across strains of rats. Young female Sprague-Dawley-derived rats were either adrenalectomized (ADX) or sham-operated (Sham) and allowed to mature 45 days before they were sacrificed for histological analysis. Fore brain sections were taken at several planes for display by projection microscope. Of the 21 sites examined, ADX exerted its greatest effect upon neocortical tissue and myelinated fiber tracts. The only other brain region affected was thalamus, which exhibited a significant widening as a result of ADX. In contrast, archicortical structures were notably unaffected by ADX. Neither the hippocampus, measured from a variety of planes, nor nuclei in the septal area were subject to increased growth by ADX. This general portrayal of ADX's site specificity held across strains of rats. However, there were local differences. Within the neopallium, the frontal region underwent the greatest thickening in one strain, while the occipital area was most strongly affected in the other. Parietal cortex was equally responsive in both strains. The pattern of sensitive vs insensitive sites bore a resemblance to the pattern of increased growth brought about by environmental enrichment as well as the fore brain distribution of Type 2 corticosterone receptors.

Adrenalectomy↗
PubMed1988

Characterization of a highly repeated satellite DNA from the cyprinid fish Notropis lutrensis.

1. A highly repeated, satellite DNA family from the North American cyprinid fish, Notropis lutrensis, was identified as a fragment band following restriction endonuclease enzyme digestion and agarose gel electrophoresis of genomic DNA; evidence of a tandem arrangement of the satellite in the genome was demonstrated by the formation of "ladders" in partial restriction endonuclease digests. 2. The satellite family was estimated densitometrically to comprise 7-8% of the N. lutrensis genome; mapping experiments using isolated and purified monomer repeat units of the satellite uncovered nine sites for seven different restriction enzymes. 3. A monomeric repeat unit of the satellite was cloned and sequenced, and found to be 174 base pairs in length and to have a base composition of 47% G + C (guanine + cytosine); computer analysis of the sequence revealed 13 new restriction sites for 12 additional enzymes. 4. Computer analysis also revealed that a large degree of internal redundancy in the monomer unit exists in the form of both direct and inverted repeating units, and that the entire sequence, starting with one base in either orientation, constitutes an open reading frame. In all but the last characteristic, the N. lutrensis satellite DNA is very similar to satellite DNAs in other eukaryotes.

Animals↗
PubMed1988

Regulation of isocitrate lyase gene expression in sunflower.

A cDNA sequence that encodes a portion of sunflower (Helianthus annuus L.) seedling isocitrate lyase was selected from a lambda gt11 cDNA library derived from sunflower seedling cotyledon poly(A)(+) messenger RNA. The library was screened for bacteriophage recombinants that expressed antigens which reacted with antisera directed against cotton seed isocitrate lyase. The isolated cDNA hybridized with a 2 kilobase RNA species that was first detectable in maturing sunflower embryos 19 days after flowering and remained at a constant low level through seed desiccation. The prevalence of this transcript in sunflower cotyledons increased by about 10-fold within 2 days after inhibition in darkness, and transcript levels began to decrease by 5 days after imbibtion. During the first 2 days of germination and growth of sunflower seedlings in light, the rate of isocitrate lyase mRNA accumulation was greater than the rate observed during this period in dark-grown seedlings, giving peak levels about 2-fold higher than corresponding levels in dark-grown seedlings. Illumination of seedlings also promoted an earlier, and more rapid decline of isocitrate lyase transcripts. Peak levels of isocitrate lyase mRNA preceded a corresponding peak in immunologically detectable isocitrate lyase polypeptides by about 24 hours. Isocitrate lyase expression in sunflower cotyledons is developmentally regulated and is modulated, in seedlings, by exposure to light. Mechanisms that control these processes appear to function primarily at the level of mRNA accumulation and are likely to involve changes in transcription rates and/or mRNA stability.

Journal Article↗
PubMed1988

Somatic cell mapping and restriction fragment analysis of bovine genes for fibronectin and gamma crystallin.

DNAs from cow-hamster and cow-mouse somatic hybrid cells segregating bovine chromosomes have been analyzed by Southern blotting and hybridization with human fibronectin and gamma crystallin probes. Concordancy of retention of these bovine genes was compared to cattle isozyme loci representing previously described syntenic groups. Bovine fibronectin (FNI) and gamma crystallin (CRYG) fragments were concordant with each other and with isocitrate dehydrogenase 1 (IDH1), representing the bovine syntenic group U17. The syntenic relationship of these genes is conserved on human chromosome 2q and also on mouse chromosome 1. In addition, bovine RFLPs were identified with both fibronectin and gamma crystallin probes. These polymorphisms will be used to study recombination between the syntenic loci in pedigreed herds and to mark a segment of the bovine genome that is likely homologous to the Lsh region of mouse chromosome 1, which confers resistance in mice to several intracellular parasites.

Animals↗
PubMed1988

Intra-articular injection for pain relief in patients awaiting hip replacement.

A double blind randomised trial was carried out to ascertain whether intra-articular injections of saline, bupivacaine or bupivacaine plus triamcinolone would be of value in the relief of hip pain suffered by patients awaiting total hip replacement for osteoarthritis. The majority of patients had good pain relief for 1 month but in general this was not maintained and some patients were much worse after the injection.

Aged↗
PubMed1987

Mortality among workers in a shoe manufacturing company.

Several epidemiologic studies have suggested that leather workers have an elevated risk of bladder cancer, nasal cancer, and leukemia. A case-control analysis of patient files at a large cancer treatment facility in New York State indicated that several bladder cancer patients had worked at a large shoe manufacturing company in upstate New York. A mortality study was initiated to determine whether there was an unusual cancer risk associated with employment in this facility. Because company records were not available, local newspaper obituaries were used to identify former company employees who died between 1960 and 1979. Proportionate mortality (PMR) analyses were conducted by using 4,734 death certificates and the general U.S. population for comparison. There were no excess deaths from nasal cancer or bladder cancer, and mortality from leukemia was slightly lower than expected. Increased relative frequencies of digestive cancers were seen among men and women. There were significant excesses of deaths from multiple myeloma among both men (PMR = 193) and women (PMR = 346).

Adolescent↗
PubMed1987

Sequence and expression of a gene encoding an albumin storage protein in sunflower.

The complete sequence of a sunflower (Helianthus annuus) gene, HaG5, encoding a 2 S albumin storage protein was determined. The predicted unprocessed precursor has 295 amino acids, is rich in glutamine residues (24%) and contains a hydrophobic amino-terminus that is similar to the consensus signal peptide. Amino acid sequencing of the mature protein revealed extensive post-translational processing. Nuclease protection and primer extension analysis indicated a major transcriptional start 30 nucleotides 5' of the predicted ATG start codon. Additional sequence data, determined from a nearly full length cDNA recombinant, indicate that HaG5 is a member of a small gene family comprised of at least two divergent genes. Comparison of the predicted HaG5 gene product with sequences of other known plant proteins revealed distant but significant homology with the napins of Brassica and other heterogeneous seed proteins in the albumin superfamily.

2S Albumins, Plant↗
PubMed1987

Isolation and characterization of abl gene sequences in Calliphora erythrocephala.

Screening of genomic DNA libraries with hybridization probes derived from a Drosophila melanogaster c-abl proto-oncogene homologue resulted in the isolation of a set of related sequences from the dipteran Calliphora erythrocephala. Although the region encompassing the c-abl protein kinase domain encodes a polypeptide extremely similar to the Drosophila gene, considerable inter- and intraspecific divergence is found adjacent to this region. Restriction-site heterogeneity and cross-hybridization studies between individual cloned isolates suggest that abl homologues represent a small gene family in the Calliphora genome. As is the case in Drosophila, abl-related transcripts appear to be low in abundance, are synthesized during oogenesis and stored as a maternal mRNA.

Animals↗
PubMed1987

Mortality from lung cancer and respiratory disease among pottery workers exposed to silica and talc.

A cohort mortality study of white men employed for at least one year between 1939 and 1966 at three plants of a single United States company was conducted to evaluate the risk of lung cancer and nonmalignant respiratory disease among workers exposed to silica dust and nonfibrous (nonasbestiform) talc in the manufacture of ceramic plumbing fixtures. Follow-up of 2,055 men through January 1, 1981, indicated a substantial excess of nonmalignant respiratory disease among those with high levels of exposure to silica dust (standardized mortality ratio = 2.26). The risk of nonmalignant respiratory disease rose with the number of years exposed, was not further enhanced by talc exposure, and appeared to be appreciably lower among those exposed in more recent time periods. For lung cancer, men exposed to high levels of silica dust with no talc exposure had a nonsignificant standardized mortality ratio of 1.37. However, those exposed to nonfibrous talc in addition to high levels of silica had a significant 2.5-fold excess risk of lung cancer. Among this group, the lung cancer standardized mortality ratio rose with increasing years of talc exposure to 3.64 among those exposed for 15 or more years. Although the role of silica as a cofactor cannot be ruled out, these data suggest that nonfibrous talc exposure is associated with excess lung cancer risk.

Drug Synergism↗
PubMed1987

Mortality among flavour and fragrance chemical plant workers in the United States.

Vital status on 1 January 1981 was determined for a cohort of 1412 white men employed in a flavour and fragrance chemical plant between 1945 and 1965 in order to investigate the risks from fatal diseases among men exposed to multiple chemicals in the manufacture of fragrances, flavours, aroma chemicals, and other organic substances. Cause specific standardised mortality ratios (SMRs) were calculated for the entire study population and for several subsets by likelihood of exposure to chemicals, duration of employment, and year of hire. SMRs for rectal cancer and ischaemic heart disease were raised among white male employees whose jobs were in production, maintenance, laboratory, or other jobs that would involve exposure to multiple chemicals used and produced in the plant. The excess of rectal cancer was confined to employees who had worked as chemical operators and mortality was significantly raised among men who worked for ten or more years. Traces of dioxin were recently found in and around plant buildings that used trichlorophenol in the production of hexachlorophene. The study group was small and had limited power to detect excess risk of rare causes of death; however, no soft tissue sarcomas were observed during the study period.

Chemical Industry↗
PubMed1987

Risk of astrocytic brain tumors associated with occupational chemical exposures. A case-referent study.

A case-referent study was conducted on the risk of brain tumors among workers exposed to organic chemicals in petroleum refining and chemical manufacturing. Brain tumor cases in northern New Jersey, Philadelphia, and the Gulf Coast of Louisiana were identified from death certificates of a recent three-year period. The cases (N = 300) were white men aged greater than or equal to 30 years with a confirmed diagnosis of glioblastoma multiforme, astrocytoma, or a mixed glioma with astrocytic cells. The referents (N = 386) were white men who died from causes other than brain tumor, epilepsy, cerebrovascular disease, suicide, or homicide and were frequency-matched with the cases on age at death, year of death, and study area. Next-of-kin were interviewed for complete occupational histories. No statistically significantly elevated odds ratios (OR) were associated with employment in the chemical industry. The risk of astrocytic tumors was elevated among the subjects with production or maintenance jobs in petroleum refining (OR 1.7, 95% confidence interval 0.7-4.2); however, it decreased with duration employed. There were nonsignificant excess risks of astrocytic tumors among the men exposed to cutting fluids (OR 1.6) or organic solvents (OR 1.3), and also among the subjects exposed to lubricating oils (OR 1.4), organic solvents (OR 1.5), or cutting fluids (OR 1.8) for greater than or equal to 20 years.

Astrocytoma↗
PubMed1987

Brain tumor mortality risk among men with electrical and electronics jobs: a case-control study.

Brain tumor risk associated with electrical and electronics jobs and with occupational exposure to microwave and radiofrequency (MW/RF) electromagnetic radiation was evaluated with the use of data from a death certificate-based case-control study of brain tumors and occupational risk factors in northern New Jersey, Philadelphia, PA, and southern Louisiana. Next-of-kin of 435 white men who died of a primary brain tumor and of 386 controls who died from other causes were interviewed to obtain information on lifetime occupational history and other factors that might be related to excess brain tumor risk. The relative risk (RR) for all brain tumors was elevated among men exposed to MW/RF radiation [RR = 1.6; 95% confidence interval (Cl) = 1.0, 2.4] and was significantly elevated among men exposed for 20 or more years. All of the excess risk for MW/RF radiation-exposed subjects was derived from jobs that involved the design, manufacture, repair, or installation of electrical or electronic equipment (RR = 2.3; 95% Cl = 1.3, 4.2), while risk of brain tumors among MW/RF radiation-exposed subjects who never worked in electrical or electronics jobs was not elevated (RR = 1.0; 95% Cl = 0.5, 1.9). Furthermore, risk was elevated for electronics workers who were considered to have no exposure to MW/RF radiation. Among electrical and electronics workers, risk was highest for engineers, teachers, technicians, repairers, and assemblers combined (RR = 3.9; 95% Cl = 1.6, 9.9) and was limited to excess risk from astrocytic tumors (RR = 4.6; 95% Cl = 1.9, 12.2). Risk of astrocytic tumors among these electronics manufacture and repair workers increased with duration of exposure to tenfold among those employed for 20 or more years. Among electricians and power and telephone linemen combined (electrical tradesmen), the RR for astrocytic tumors was slightly elevated, but not statistically significant (RR = 1.8), and showed no consistent evidence of a duration-response relationship. Electrical tradesmen are exposed to extremely low frequency electromagnetic radiation, while men in some jobs associated with electronics manufacture and repair are exposed to electromagnetic radiation in the very high frequency and ultra-high frequency ranges and also may be exposed to soldering fumes, solvents, and a variety of other chemicals.

Astrocytoma↗
PubMed1987

Occupational risks for meningiomas of the CNS in Sweden.

Using the Cancer-Environment Registry of Sweden, which links cancer incidence (1961 to 1979) with census information (1960) for all employed individuals in Sweden, a systematic, population-based assessment was made of the occurrence of meningiomas of the CNS according to industrial and occupational classifications. Statistically significant standardized incidence ratios (SIR) between 5 and 6 for meningioma were observed among glass, porcelain, or ceramic workers of both sexes. SIRs of similar magnitude were also found for men employed in the headwear fabrication and book publishing industries. Significantly elevated two- to three-fold risks were observed for men employed in health care, railroad and trolley construction, sheet and plate metal fabrication, and as moving equipment operators. Some of the findings of this descriptive survey may have arisen as a result of multiple comparisons, but several are consistent with earlier observations for brain cancer from other countries and deserve further study.

Central Nervous System Diseases↗
PubMed1986

Occupational risk factors for brain tumors. A case-referent death-certificate analysis.

Numerous studies have suggested that employment in the oil refining and chemical manufacturing industries may be associated with excess brain tumor risk. A case-referent study was undertaken to evaluate brain tumor risk by occupation and industry in three geographic areas (northern New Jersey, Philadelphia, and the Gulf Coast of Louisiana) with a heavy concentration of these industries. Seven hundred and eighteen white men dying from brain tumor at age 30 years or older were ascertained from death certificates for 1978-1981. The referents were men who died of other causes, excluding epilepsy and stroke. Usual occupation and industry were obtained from the death certificates, and the maximum likelihood estimates of the relative risk were calculated for specific industries and occupations. Small nonsignificant excess risks of brain tumors were seen among persons whose usual employment was in the petroleum refining, electrical equipment manufacturing, health services, and educational services industries. Compared with other white-collar professionals, health diagnosticians, teachers, and artists/designers had a significantly elevated brain tumor risk. Among blue-collar workers, the only group with a significantly elevated brain tumor risk was precision metal workers, who are exposed to metal dusts and fumes and substances used as coolants, lubricants, and degreasers.

Adult↗
PubMed1985

Proportionate mortality among male corn wet-milling workers.

Workers in the corn wet-milling industry are exposed to grain dusts, pesticides and fumigants, acids, solvents, sulphur dioxide, and other chemicals used in the manufacture of starch, oil, syrup, and dextrins. In a preliminary investigation of the long-term health effects of occupational exposures in this industry, deaths among active and retired corn wet-milling workers were identified from records of a trade union. Underlying cause of death for workers who died between 1947 and 1981 was determined from death certificates. Cause-specific Proportionate Mortality Ratios (PMR's) were computed for white and black males using US males as a comparison with adjustments for age, race, and calendar year of death. There were deficits of deaths from respiratory and digestive diseases. Among whites, mortality from chronic nephritis, bladder cancer, and lymphatic and haematopoietic malignancies was elevated. There was an elevated frequency of deaths due to diabetes and a threefold excess of pancreatic cancer deaths among blacks. Crude work history information indicated a small cluster of pancreatic cancer deaths among whites and blacks who had worked in production processes that convert corn starch to syrup and dextrins. An elevated frequency of deaths from leukaemia was seen among white maintenance workers.

Black People↗
PubMed1984

Sea urchin actin gene subtypes. Gene number, linkage and evolution.

The actin gene family of the sea urchin Strongylocentrotus purpuratus was analyzed by the genome blot method, using subcloned probes specific to the 3' terminal non-translated actin gene sequence, intervening sequence and coding region probes. We define an actin gene subtype as that gene or set of genes displaying homology with a given 3' terminal sequence probe, when hybridized at 55 degrees C, 0.75 M-Na+. By determining the often polymorphic restriction fragment band pattern displayed in genome blots by each probe, all, or almost all of the actin genes in this species could be classified. Our evidence shows that the S. purpuratus genome probably contains seven to eight actin genes, and these can be assigned to four subtypes. Studies of the expression of the genes (Shott et al., 1983) show that the actin genes of three of these subtypes code for cytoskeletal actins (Cy), while the fourth gives rise to a muscle-specific actin (M). We denote the array of S. purpuratus actin genes indicated by our data as follows. There is a single CyI actin gene, two or possibly three CyII genes (CyIIa, CyIIb, and possibly CyIIc), three CyIII actin genes (CyIIIa, CyIIIb, CyIIIc), and a single M actin gene. Comparative studies were carried out on the actin gene families of five other sea urchin species. At least the CyIIa and CyIIb genes are also linked in the Strongylocentrotus franciscanus genome, and this species also has a CyI gene, an M actin gene and at least two CyIII actin genes. It is not clear whether it also possesses a CyIIc actin gene, or a CyIIIc actin gene. The genome of a more closely related congener, Strongylocentrotus dröbachiensis, includes 3' terminal sequences suggesting the presence of a CyIIc gene. In S. franciscanus and S. dröbachiensis the first intron of the CyI gene has remained homologous with intron sequences of both the CyIIa and CyIIb genes, indicating a common origin of these three linked cytoskeletal actin genes. Of the four S. purpuratus 3' terminal subtype probe sequences only the CyI 3' terminal sequence has been conserved sufficiently during evolution to permit detection outside of the genus Strongylocentrotus. An unexpected observation was that a sequence found only in the 3' untranslated region of the CyII actin gene in the DNA of S. dröbachiensis and S. purpuratus is represented as a large family of interspersed repeat sequences in the genome of S. franciscanus.

Actins↗
PubMed1984

Cancer mortality patterns by work category in three Texas oil refineries.

A previous proportionate mortality ratio analysis revealed elevated mortality from brain tumors, stomach cancer, leukemia, and other cancers among OCAW members employed in three Texas oil refineries. In order to evaluate these findings, complete work histories of cases and a matched set of controls who died from other causes of death were obtained from company personnel records. Work histories were summarized by classifying each job title and department entry into one of several broad work categories of refinery unit operations. A worker was considered "exposed" to a work category if he was known to have worked at least 1 day in the category 15 or more years prior to his death. Maximum likelihood estimates of the relative risk for brain tumor, stomach cancer, and leukemia were calculated by work category using a procedure for matched case-control data. No strong associations for brain tumor risk were seen with any work categories. A slight association for leukemia was seen among workers in the Treating category, which included unit operations that reduce the level of aromatic and sulfur constituents of petroleum products and combine them with additives to improve their quality. Stomach cancer risk was elevated among maintenance workers and workers exposed to lubricating oils and paraffin wax processing.

Brain Neoplasms↗