How to develop an effective obstetric checklist.

Checklists to guide critical procedures are becoming an increasingly important part of medical practice. These tools have proved effective in improving outcome in a variety of medical settings, including obstetrics. In this review, we outline essential principles of successful checklist creation and implementation and review our experience with checklist development in a worldwide, multi-institutional health care delivery system.

SWAP pre-mRNA splicing regulators are a novel, ancient protein family sharing a highly conserved sequence motif with the prp21 family of constitutive splicing proteins.

Regulators responsible for the pervasive, nonsex-specific alternative pre-mRNA splicing characteristic of metazoans are almost entirely unknown or uncertain. We describe here a novel family of splicing regulators present throughout metazoans. Specifically, we analyze two nematode (Caenorhabditis elegans) genes.

mRNAs that mature through trans-splicing in Caenorhabditis elegans have a trimethylguanosine cap at their 5' termini.

Approximately 10% of the mRNAs in the nematode Caenorhabditis elegans mature through a trans-splicing mechanism that involves the transfer of a 22-nucleotide spliced leader to the 5' end of the pre-mRNA. The spliced leader RNA exists as a small nuclear ribonucleoprotein particle and has the trimethylguanosine cap that is characteristic of eucaryotic small nuclear RNAs. We found that the trimethylguanosine cap present on the spliced leader RNA was transferred to the pre-mRNA during the trans-splicing reaction.

Trans-spliced leader RNA exists as small nuclear ribonucleoprotein particles in Caenorhabditis elegans.

Maturation of some messenger RNAs in the nematode Caenorhabditis elegans involves the acquisition of a 22-base leader at their 5' ends. This 22-base leader, called the spliced leader (SL), is derived from the 5' end of a precursor RNA of 90-100 bases, called spliced leader RNA (SL RNA). SL RNA is transcribed from a 1-kilobase DNA repeat which also encodes the 5S ribosomal RNA.

Trans splicing involves a novel form of small nuclear ribonucleoprotein particles.

The trans-splicing reaction occurring in trypanosomes and related species as well as in the nematode Caenorhabditis elegans involves the transfer of a 5' exon from a spliced leader transcript (SL RNA) to a precursor messenger RNA transcript with a 3' splice acceptor site. This seems to take place in the same nuclear compartment as normal cis splicing and proceeds through Y-branched intermediates analogous to the lariats formed in cis splicing. The cellular machinery catalysing cis and trans splicing might therefore be expected to share some components, particularly in the nematode where some mRNAs are produced by both cis and trans splicing.

Presence of the Caenorhabditis elegans spliced leader on different mRNAs and in different genera of nematodes.

Several different mRNAs from Caenorhabditis elegans contain the same 22-nucleotide leader sequence at their 5' ends that is acquired in a trans-splicing reaction. About 10 to 15% of the major proteins are translated from mRNAs that contain the spliced leader, among them two ribosomal proteins, ubiquitin, GAPDH, a heat shock protein (hsp70a), and three actins. The same spliced leader sequence is present in mRNAs isolated from nematodes from several different genera; but it is not present in mRNAs from other organisms.

Maturation of the major ubiquitin gene transcript in Caenorhabditis elegans involves the acquisition of a trans-spliced leader.

Recently, studies on the 5'-ends of actin mRNAs in the nematode, Caenorhabditis elegans, have demonstrated that three of the four mature actin transcripts contain a 22-nucleotide leader sequence which is acquired by trans-splicing from a novel 100-nucleotide RNA. In the course of our studies of the ubiquitin genes in C. elegans (R.

Stable gene transfer and tissue-specific expression of a human globin gene using adenoviral vectors.

Helper-free double recombinant adenoviruses containing a genomic human globin gene and the neomycin resistance gene (neoR) have been constructed. The inserted globin and neoR genes are stable and transcription of two human globin genes (beta and a hybrid gamma-beta gene) is correctly initiated at the respective globin promoter during lytic infection in 293 cells. The neoR gene driven by the SV40 early promoter confers G418 resistance to human fibroblasts and K562 human erythro-leukemia cells transformed with these viruses.

Efficient transformation of human fibroblasts by adenovirus-simian virus 40 recombinants.

The origin-defective simian virus 40 (SV40) mutant 6-1 has been useful in transforming human cells (Small et al., Nature [London] 296:671-672, 1982; Nagata et al., Nature [London] 306:597-599, 1983).

Infection of eucaryotic cells by helper-independent recombinant adenoviruses: early region 1 is not obligatory for integration of viral DNA.

Recombinant viral genomes carrying a selectable drug resistance marker have been constructed by insertion of a hybrid gene for neomycin resistance into the helper-independent adenovirus vector, delta E1/X. The hybrid gene consists of sequences coding for the aminoglycoside 3'-phosphotransferase II from Tn5, under the control of the simian virus 40 early promoter, and renders mammalian cells resistant to the neomycin analog, G-418. Most of adenovirus early region 1 is deleted from delta E1/X (nucleotides 455 to 3330), and recombinant viral genomes carry the hybrid gene in its place.

Palindromic adenovirus type 5-simian virus 40 hybrid.

A family of novel adenovirus type 5-simian virus 40 (Ad5-SV40) recombinants (Ad5++D1) whose genomes consist of symmetrically inverted structures was isolated. Particles of Ad5++D1 could contain one of several recombinant genomes that differed incrementally from one another by a full-length copy of linear SV40 DNA. The members of the Ad5++D1 family appeared to be in genetic equilibrium with one another.

Actin gene expression in developing sea urchin embryos.

We show that the synthesis of actin is regulated developmentally during early sea urchin embryogenesis and that the level of synthesis of this protein parallels the steady-state amounts of the actin messenger ribonucleic acids (RNA). An in vitro translation and RNA blotting analysis of embryo RNA from several stages of early development indicated that during the first 8 h after fertilization there was a low and relatively constant level of actin messenger RNA in the embryo. Between 8 and 13 h of development, the amount of actin messenger RNA began to increase both in the cytoplasm and on polysomes, and by 18 h the amounts of actin message per embryo had risen between approximately 10- and 25-fold in the cytoplasm and between 15- and 40-fold on polysomes.