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Biomedical subjects

M Eaton

Publications and source records attributed to M Eaton.

30 records · Page 2Linked to original sources
PubMed1986

Seven-year follow-up of workers exposed to 1,2-dibromo-3-chloropropane.

A follow-up report was done of workers exposed to 1,2-dibromo-3-chloropropane (DBCP) 7 years after termination of exposure. A 1977 study of male pesticide workers exposed to DBCP in a California agricultural chemical plant identified many who were azoospermic or oligospermic. Sperm concentration and serum follicle-stimulating hormone (FSH) levels in 44 of these workers were reassessed 5 to 8 years after exposure was terminated in 1977. Two of the eight originally azoospermic workers produced sperm during the follow-up, although only one had normal sperm counts. No increase in sperm production could be detected in men who had low sperm counts in 1977, and elevated serum FSH levels did not drop in oligospermic or azoospermic men. These results suggest that permanent destruction of germinal epithelium occurs in most DBCP-sterile persons.

Follicle Stimulating Hormone↗
PubMed1984

Codon usage can affect efficiency of translation of genes in Escherichia coli.

By inserting synthetic oligonucleotides into a highly expressed gene in E. coli it has been shown that unfavourable codon usage can reduce the maximum translation rate of a protein. However, in the case of the codon used (AGG), a significant effect on translation was only seen at very high transcription rates from a gene containing multiple copies of the unfavourable codon.

Bacterial Proteins↗
PubMed1982

Cloning of the am (glutamate dehydrogenase) gene of Neurospora crassa through the use of a synthetic DNA probe.

In a previous study the alteration in the amino acid sequence of Neurospora crassa NADP-specific glutamate dehydrogenase (GDH) resulting from two mutually compensating frameshift mutations was used to deduce the first 17 nucleotides of the coding sequence of the am gene. In the work reported here, a synthetic 17-mer corresponding to the deduced sequence was shown to hybridize strongly to a 9-kb HindIII fragment from N. crassa wild-type DNA but not to any corresponding fragment from the DNA of a mutant strain known to be deleted for most or all of the gene. Wild-type HindIII fragments were fractionated for size and a fraction centering around 9 kb was cloned in vector lambda L47. Two clones carrying the strongly hybridizing fragment were identified. The hybridization to the 17-mer was localized within a 2.7-kb BamHI fragment and, within this, to a 700-bp BamHI-Bg/II subfragment. 5' end-labelled polyadenylated RNA isolated from wild-type mycelium hybridized to the 2.7-kb BamHI fragment and not appreciably to flanking fragments. The partial sequence analysis of the BamHI-Bg/II fragment has confirmed that the 17-mer probe matches the coding sequence at the 5' end of the gene and has also revealed an intervening sequence 67 bp in length, interrupting codon 15. Both the 9-kb HindIII fragment and the 2.7-kb BamHI fragment have been shown to be capable of transforming the deletion mutant to prototrophy and ability to produce GDH. Analysis of one transformant showed that the am gene was integrated, together with a part of the long arm of the lambda vector, at an unusual locus. This transformant, in which the am gene does not show its normal linkage to the linkage group 5 marker inl, was found to produce GDH to about 20% of the normal level.

Bacteriophage lambda↗
PubMed1980

The expression in E. coli of synthetic repeating polymeric genes coding for poly(L-aspartyl-L-phenylalanine).

Two dodecadeoxynucleotides of defined sequence have been synthesised by phosphotriester methodology. They can be polymerised to give a double stranded DNA which codes, when read in the correct phase, for the repeating dipeptide poly(aspartyl-phenylalanine). This polymeric DNA has been cloned in E. coli K12 using as vector a plasmid having a controllable bacterial promoter upstream of the insertion site. Clones containing genes coding for up to 150 repeats of (aspartyl-phenylalanine) have been isolated and characterised. The polymeric inserts appear to be stable over many generations and are expressed in E. coli under the control of the bacterial promoter, to give a polymer of phenylalanine and aspartic acid which may be broken down enzymically to yield aspartyl-phenylalanine.

Amino Acid Sequence↗
PubMed1978

Health team function: testing a method for improvement.

Health-care teams are functioning in the delivery of primary care. For purposes of this paper, the health-care team is composed of a primary care physician or physicians working with other health-care providers to deliver primary care. This definition represents an organizational model of health-care teams. Organizational specialists have proposed "team development" processes for improving health team function. This paper reports the results of an initial experiment designed to analyze the results of such a process. A modification of the "health-team development" process was used with one of three comparable teams at a family practice residency. Pre and post-team development data were taken. The team that experienced the modified team development process showed significant differences in the gain scores, compared to the "control" teams. Discussion focuses on the role of organizational technology in health-care teams and avenues of further analysis are presented. The modified format for the team development process is also reported and discussed.

Evaluation Studies as Topic↗
PubMed1977

Ouabain-sensitive liver and diaphragm respiration in cold-acclimated hamster.

The in vitro respiratory rates of liver and diaphragm from hamsters were compared before and after prolonged cold exposure (5 degrees C, 3-4 wk). In the presence or absence of glucose, respiratory rates were elevated in both tissues from the cold-acclimated hamsters, and these cold-induced increases were significantly reduced by ouabain. This ouabain inhibition is consistent with the hypothesis that cold exposure of these rodents stimulates the energy demands of the Na+/K+ transport system in liver and diaphragm, with these demands providing a driving force, at least in part, for respiration and accompanying cellular thermogenesis.

Acclimatization↗
PubMed1976

Absence of 5' terminal capping in encephalomyocarditis virus RNA.

The nature of the 5' terminus of encephalomyocarditis (EMC) virion RNA has been investigated. We have failed to detect any capped products or nucleoside polyphosphates arising upon complete digestion of the RNA with T1, T2, and pancreatic ribonucleases, and it would therefore appear that the 5' terminus of EMC virus RNA is not phosphorylated and not capped with m7G. EMC virions do contain, however, large amounts of all four 5'-monosubstituted nucleoside triphosphates (4.2M pppG; 16.4M pppA; 3.OM pppU and 2.5M pppC), of which at least a proportion (about 15-20%) appear to remain bound to fully denatured RNA in the presence of divalent cations.

Base Sequence↗
PubMed1975

The effect of adrenergic agonists and cyclic AMP on the Na+/K+ ATPase activity of brown adipose tissue.

The Na+/K+ ATPase activity of membrane fractions prepared from brown adipose tissue of cold-acclimated rats could be stimulated by addition of any one of the following: norepinephrine, isoproterenol, cyclic AMP or phenylephrine. These results are consistent with the proposal that in the intact brown adipocyte, the norepinephrine-induced stimulation of the Na+/K+ membrane pump is associated with alpha- as well as beta-adrenergic pathways and is, in part, mediated via cyclic AMP.

Adenosine Triphosphatases↗