PubMed Health⌕ Search

Biomedical subjects

L J Fish

Publications and source records attributed to L J Fish.

4 recordsLinked to original sources
PubMed1999

'Green revolution' genes encode mutant gibberellin response modulators.

World wheat grain yields increased substantially in the 1960s and 1970s because farmers rapidly adopted the new varieties and cultivation methods of the so-called 'green revolution'. The new varieties are shorter, increase grain yield at the expense of straw biomass, and are more resistant to damage by wind and rain. These wheats are short because they respond abnormally to the plant growth hormone gibberellin. This reduced response to gibberellin is conferred by mutant dwarfing alleles at one of two Reduced height-1 (Rht-B1 and Rht-D1) loci. Here we show that Rht-B1/Rht-D1 and maize dwarf-8 (d8) are orthologues of the Arabidopsis Gibberellin Insensitive (GAI) gene. These genes encode proteins that resemble nuclear transcription factors and contain an SH2-like domain, indicating that phosphotyrosine may participate in gibberellin signalling. Six different orthologous dwarfing mutant alleles encode proteins that are altered in a conserved amino-terminal gibberellin signalling domain. Transgenic rice plants containing a mutant GAI allele give reduced responses to gibberellin and are dwarfed, indicating that mutant GAI orthologues could be used to increase yield in a wide range of crop species.

Alleles↗
PubMed1999

Methods to encourage the use of antenatal corticosteroid therapy for fetal maturation: a randomized controlled trial.

CONTEXT: Antenatal corticosteroids for fetal maturation have been underused, despite evidence for their benefits in cases of preterm birth. OBJECTIVE: To evaluate dissemination strategies aimed at increasing appropriate use of this therapy. DESIGN AND SETTING: Twenty-seven tertiary care institutions were randomly assigned to either usual dissemination of practice recommendations (n = 14) or usual dissemination plus an active, focused dissemination effort (n = 13). SUBJECTS: Obstetricians and their preterm delivery cases at participating hospitals. INTERVENTION: Recommendations by a National Institutes of Health (NIH) Consensus Conference held in late February-early March 1994 were disseminated in early May 1994. Usual dissemination was publication of the recommendations and endorsement by the American College of Obstetricians and Gynecologists. Active dissemination was a year-long educational effort led by an influential physician and a nurse coordinator at each facility, consisting of grand rounds, a chart reminder system, group discussion of case scenarios, monitoring, and feedback. MAIN OUTCOME MEASURE: Use or nonuse of antenatal corticosteroids was abstracted from medical records of eligible women delivering at the participating hospitals in the 12 months immediately prior to release of the NIH recommendations (average number of records abstracted, 130) and in the 12 months following their release (average number of records abstracted, 122). RESULTS: Active dissemination significantly increased the odds of corticosteroid use after the conference. Use increased from 33.0% of eligible patients receiving corticosteroids to 57.6%, or by 75% over baseline, in usual dissemination hospitals. Use increased from 32.9% to 68.3%, oran 108% increase, in active dissemination hospitals. Gestational age and maternal diagnosis affected use of the therapy in complex ways. CONCLUSION: An active, focused dissemination effort increased the effectiveness of usual dissemination methods when combined with key principles to change physician practices.

Anti-Inflammatory Agents↗
PubMed1999

Induction and characterization of Ph1 wheat mutants.

The cloning of genes for complex traits in polyploid plants that possess large genomes, such as hexaploid wheat, requires an efficient strategy. We present here one such strategy focusing on the homologous pairing suppressor (Ph1) locus of wheat. This locus has been shown to affect both premeiotic and meiotic processes, possibly suggesting a complex control. The strategy combined the identification of lines carrying specific deletions using multiplex PCR screening of fast-neutron irradiated wheat populations with the approach of physically mapping the region in the rice genome equivalent to the deletion to reveal its gene content. As a result, we have located the Ph1 factor controlling the euploid-like level of homologous chromosome pairing to the region between two loci (Xrgc846 and Xpsr150A). These loci are located within 400 kb of each other in the rice genome. By sequencing this region of the rice genome, it should now be possible to define the nature of this factor.

Base Sequence↗