Search PubMed⌕ Search

Biomedical subjects

T L Thomas

Publications and source records attributed to T L Thomas.

At least 91 records · Page 5Linked to original sources
PubMed1983

Poly(A) RNA of the egg cytoplasm: structural resemblance to the nuclear RNA of somatic cells.

This paper concerns the structural characteristics of the poly(A) RNA stored in unfertilized amphibian and echinoderm eggs. Though located in the egg cytoplasm, at least two-thirds of these maternal transcripts display an interspersed sequence organization similar to that of nuclear RNA. In Xenopus laevis interspersed poly(A) RNA molecules are synthesized and deposited in the oocyte cytoplasm throughout the main growth phase of oogenesis. Regions of the sea urchin genome that are represented by interspersed maternal transcripts have been recovered from recombinant clone libraries. In one case the same single-copy sequence is found both in an abundant message-sized 1.6 kilobase (kb) maternal transcript and in a 7.5 kb maternal transcript that structurally resembles a precursor form and is not found in embryonic polysomes. In a second example considered, a 9.5 kb transcript was identified in embryo nuclear RNA that may be identical in structure with an interspersed maternal poly(A) RNA derived from the same transcription unit. Transcription of this sequence appears to be constitutive in somatic cell nuclei, though no homologous cytoplasmic RNAs are found after early cleavage. This may be a widespread form of regulation for transcription units expressed in female germ cells, and represented in the maternal poly(A) RNA pools of unfertilized eggs.

Animals↗
PubMed1982

Habitual anterior subluxation of the head of the ulna treated by Baldwin's operation. A case report.

A case of habitual anterior subluxation of the ulna at the inferior radio-ulnar joint is reported. The subluxation presented with signs and symptoms of both ulnar amd median neuritis. There was no past history of trauma. Baldwin's procedure was carried out, stabilising the distal radio-ulnar joint and relieving all symptoms of nerve compression. The use of Baldwin's procedure to correct this condition has not previously been described.

Adult↗
PubMed1982

A preliminary investigation of mortality among workers in the pottery industry.

Early studies of mortality among workers in the pottery industry indicated elevated mortality from tuberculosis and non-malignant respiratory disease. Although raw materials and production processes have changed very little some fibrous materials such as talc have been introduced into the industry during the past 20 to 30 years. This prompted a mortality study of pottery workers to examine patterns of fatal disease among individuals exposed to dust particles during the production of ceramics. Deaths among active and retired pottery workers were identified from records of the international Brotherhood of Potters and Allied Workers (IBPAW). Underlying cause of death was determined from death certificates obtained from state vital records offices for 2924 white males and 946 white females who died between 1955 and 1977. Cause-specific Proportionate Mortality Ratios (PMRs) were calculated using the total United States as a standard. PMRs fro tuberculosis and non-malignant respiratory disease were elevated among males and females, particularly those whose occupations were associated with high levels of dust exposure. A significantly elevated frequency of lung cancer occurred exclusively among white males who had been employed in the manufacture of ceramic plumbing fixtures.

Adult↗
PubMed1982

Mortality patterns among workers in three Texas oil refineries.

The cause-specific mortality experience of 2,509 active and retired members of the Oil, Chemical, and Atomic Workers International Union (OCAW) who worked at three oil refineries in the Beaumont/Port Arthur area of Texas was examined to determine whether there might be unusual patterns of fatal disease related to workplace exposures. Deaths that occurred between 1943 and 1979 were identified from membership records of the OCAW headquarters in Denver and from the records of union locals in Texas which represent workers at the three refineries. Death certificates were obtained from state vital records offices for the decedents. Cause-specific Proportionate Mortality Ratios (PMRs) were calculated using the mortality experience of the U.S. general population as a standard. Excess mortality from stomach cancer occurred among active union members who worked at Refinery A and among active and retired members who worked at Refineries B and C. PMRs for leukemia, multiple myeloma, and other lymphomas were elevated, especially among retired workers. Relative frequencies of brain tumor deaths were significantly elevated among active members at all three refineries and slightly elevated among retirees at Refineries A and C. Findings suggest that oil refinery workers may have elevated risks of these cancers and indicate that more definitive studies are necessary.

Adult↗
PubMed1981

Molecular structure of maternal RNA.

The presence of a stable maternal mRNA population in mature oocytes of many species is well established. In this paper we show that the mature egg contains, in addition to these mature mRNAs, a structurally more complex population of RNA transcripts. This latter class of RNA consists of polyadenylated transcripts of repetitive and nonrepetitive DNA elements covalently linked into long interspersed molecules. As much as seventy percent of the polyadenylated egg RNA of Xenopus laevis and Strongylocentrotus purpuratus is represented in this interspersed population. Most of the nonrepetitive DNA sequences represented in the mature mRNA population are also present in the interspersed RNA. These transcripts have an organization similar to that of somatic cell nuclear RNA. Data are presented that suggests some of these interspersed maternal transcripts are unprocessed precursor-like molecules. Some possible functions of this novel class of RNA during early development are discussed.

Animals↗
PubMed1981

Organization and expression of multiple actin genes in the sea urchin.

A set of at least 11 actin genes has been isolated from genomic recombinant deoxyribonucleic acid libraries of the sea urchin Strongylocentrotus purpuratus. Most of the isolates derive from a library which represents the genome of a single animal. There are at least five distinct types of sea urchin actin gene, some of which are represented by multiple copies in the genome. The actin gene types are distinguished by nonhomologous flanking sequences and intervening sequences, though the protein coding sequences appear in most cases to be quite similar. Eight of the 11 genes isolated have been recovered in lambda recombinants that contain two actin genes, linked at 5- to 9-kilobase distances. Restriction map overlaps suggest that the genome contains an array of at least three of these genes spaced over about 30 kilobases of deoxyribonucleic acid. In the linkage patterns observed, actin genes of diverse types were linked to each other. In early embryos, actin messenger ribonucleic acid (RNA) transcripts of 1.8 and 2.2 kilobases were found, and the longer of these transcripts was more prevalent in the maternal RNA of the egg. From RNA gel blot experiments, we conclude that the two transcripts derive from different actin gene types. Different repetitive sequences were located to either side of most of the actin genes, and in most observed cases the repeat sequences which were adjacent to actin genes of a given type were similar. The repeat sequences flanking the actin genes belonged to families which were transcribed, but those repeats in the neighborhood of the actin genes which have been investigated were not themselves represented in the stable RNAs of eggs or early embryos.

Actins↗
PubMed1981

Some aspects of the fractured scaphoid.

Ninety-three patients who presented at a district general hospital in one year with a suspected or actual scaphoid fracture were studied. Certain changes in the accepted management of scaphoid fractures, particularly the radiology of these fractures, are suggested. These changes could result in significant savings of time and money. A new investigation is described which may prove helpful in the long-term prognostic assessment of patients who have suffered a scaphoid fracture.

Carpal Bones↗
PubMed1981

A comparative study of methods for treating fractures of the distal half of the femur.

A comparative study of methods for treating fractures of the distal half of the femur was carried out prospectively in the five-year period January 1973 to December 1977. The three methods compared were conservative treatment on a Thomas' splint, application of a knee-hinged cast-brace at five to seven weeks, and intramedullary nailing. The time in bed, in hospital and to union were compared as was the rate of functional recovery of the knee. It is concluded that the cast-brace provides a safe reliable method of treatment, combining the advantages of non-operative management with the early mobilisation possible with intramedullary fixation but without the disadvantages of surgical treatment.

Adolescent↗
PubMed1980

Four sizes of transcript produced by a single sea urchin gene expressed in early embryos.

This report concerns a set of sea urchin egg and embryo transcripts complementary to a single-copy region of a cloned DNA fragment (Sp88). Three distinct 16-cell embryo polysomal RNA species were found to hybridize with this fragment. These RNAs are about 1700, 3000, and 4000 nucleotides (nt) in length, and the same species were identified in unfertilized eggs. A significant fraction of all three species of the egg and early embryo transcripts is polyadenylylated. At gastrula stage Sp88 transcripts are almost completely confined to the nucleus [Lev, Z., Thomas, T. L., Lee, A. S., Angerer, R. C., Britten, R. J. & Davidson, E. H. (1980) Dev. Biol, 75, in press]. The Sp88 transcripts of gastrulae are present as a fourth RNA species approximately 5800 nt in length. The four species share a sequence element of cloned DNA fragment that is about 1000 nt long. These RNAs constitute a set of alternative partially overlapping transcripts from the same genomic region.

Animals↗
PubMed1980

Mortality among workers employed in petroleum refining and petrochemical plants.

The cause-specific mortality experience of 3,105 members of the Oil, Chemical and Atomic Workers International Union was examined to determine if there were unusual patterns of fatal disease that may be indicative of hazardous agents in the work environment. Deaths among active Union members that were reported by locals in Texas between 1947 and 1977 were identified through membership records, and proportionate mortality was analyzed in several broad industrial categories. PMRs for cancers of the liver and biliary passages, pancreas, lung and skin were elevated among refinery and petrochemical plant workers; however, risks did not increase with length of membership. Increased relative frequencies of stomach cancer, cancer of the brain, leukemia and multiple myeloma were confined to white males in the same category who had been Union members for 10 or more years. Excess deaths from stomach cancer and brain cancer were found among white male members employed at one specific oil refinery and petrochemical plant. Observed numbers of deaths from cancer of the stomach were greater than expected among whites and nonwhites, and an elevated PMR for lung cancer among nonwhites was found at an additional plant. Findings suggest that workers in this industry may be at increased risk of certain cancers and indicate areas for further investigation.

Adult↗
PubMed1980

Heparin lock: a cost-effective method of increasing safety of intravenous therapy.

A cost-effective method of intravenously administering medication and maintaining patent intravenous access via a heparin lock has been proposed. Although this technique is by no means new, it has not received enough recognition for safety, convenience, and adaptability in the oral and maxillofacial surgery office. The increased cost over direct venipuncture is only about $.70 to $1.00, which is considerably less expensive than the use of a continuous infusion for each patient.

Cost-Benefit Analysis↗
PubMed1979

Leukemia among Nebraska farmers: a death certificate study.

The risk of leukemia among farmers was studied using records of death certificates from Nebraska, 1957--1974. Comparison of occupation, as recorded on the death certificate, for 1084 leukemia deaths and 2168 deaths from other causes, matched for age at death, year of death, county of residence, race, and sex, revealed an elevated risk of leukemia among farmers (odds ratio = 1.25). The risk was greatest among farmers born after 1900 and dying before age 66 (odds ratio = 1.83). Stratification by county of residence showed a significantly elevated risk for farmers from heavy corn producing counties.

Adult↗