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Biomedical subjects

P M Gannon

Publications and source records attributed to P M Gannon.

10 recordsLinked to original sources
PubMed1999

Therapeutic modalities for the management of cerebral vasospasm: timing of endovascular options.

OBJECTIVES: To determine if a window of time could be defined during which angioplasty would be most effective in reversing neurological decline and ultimately improving outcome. METHODS: Of a group of 466 patients, 93 underwent endovascular management of clinical vasospasm that was medically refractory. Eighty-four of the 93 patients were available for follow-up for at least 6 months. All patients underwent mechanical angioplasty using compliant microballoon systems and, if distal spasm was present, the administration of papaverine. RESULTS: Fifty-one patients underwent endovascular management within a 2-hour window, and 33 patients underwent treatment more than 2 hours after the development of their symptoms. Compared with the group treated more than 2 hours after neurological decline (P < 0.01; chi2 = 8.02), the group that underwent endovascular management within a 2-hour window after the development of symptoms demonstrated sustained clinical improvement. CONCLUSION: When a patient develops symptomatic vasospasm and is unresponsive to traditional measures of critical care management, angioplasty may be effective in improving the patient's neurological status if this procedure is performed as early as possible. The results indicate that a 2-hour window may exist for restoration of blood flow to ultimately improve the patient's outcome.

Angioplasty, Balloon↗
PubMed1995

An inducible acid phosphatase from the yeast Pichia pastoris: characterization of the gene and its product.

To develop the budding yeast Pichia pastoris (Pp) as a model system for the study of protein secretion, we have characterized a secreted acid phosphatase (Pho1p) from this yeast. Pho1p can be induced 100-fold by starvation for phosphate. The enzyme was purified to homogeneity from a cell-wall extract by DEAE-Sepharose chromatography. We selected mutants that lacked extracellular phosphatase activity and the gene (PHO1) encoding Pho1p was isolated from a recombinant plasmid library of Pp DNA by complementation of the mutant defect. PHO1 encodes a protein of 468 amino acids (aa) with homology to repressible acid phosphatases from other yeast species. The sequence contains a 15-aa N-terminal signal sequence and six potential N-linked glycosylation sites. Antiserum to Pho1p was used to show that Pho1p transits the Pp secretory pathway in less than 5 min.

Acid Phosphatase↗
PubMed1993

Mutations of the molecular chaperone protein SecB which alter the interaction between SecB and maltose-binding protein.

SecB is a 16-kDa cytosolic chaperone protein that is required for efficient export of particular proteins in Escherichia coli. To identify regions of SecB that contribute to efficient protein export, we isolated secB point mutants that are defective for protein export in vivo. We obtained missense mutations at residues Leu75 (SecBL75Q), Cys76 (SecBC76Y), and Glu77 (SecBE77K) in the center of the secB gene. In vivo, mutant SecBL75Q and SecBE77K proteins are capable of binding to precursor maltose-binding protein (MBP) and preventing the formation of export-incompetent precursor MBP; however, export of MBP is still defective. In vitro, purified SecBL75Q and SecBE77K proteins bound to unfolded MBP and blocked its refolding. SecBL75Q and SecBE77K were more effective than wild-type SecB at blocking the refolding of unfolded MBP, suggesting that SecBL75Q and SecBE77K have a higher affinity for unfolded MBP.

ATP-Binding Cassette Transporters↗
PubMed1992

Pharmacy-nursing facsimile systems: set-up considerations and operational issues.

The use of facsimile (fax) machines for the electronic transmission of physician's orders from nursing areas to a hospital pharmacy has become increasingly popular. Although the uses and benefits of fax machines are straightforward in this practice setting, namely a significant decrease in order processing turn around time, the problems that may develop are often not described in the literature. This article describes some of the set-up concerns, operational problems, forms considerations, staff training, paper costs, equipment needs, transmission volume, and equipment maintenance involved with fax systems.

Hospital Bed Capacity, 300 to 499↗
PubMed1991

Documentation of drug interchange in the medical record.

The hospital medical record has become increasingly exposed to retrospective audits by third party insurers, quality assessment studies, and billing inquiries. As a result, the demand for complete documentation in the record has steadily increased during the past few years. Institutional medical practices are subject to a variety of regulations and standards. Economic pressures are continually exerted on hospitals for cost reduction measures, which include patient drug costs. While hospitals have engaged in a variety of methods of drug interchange to reduce costs, documentation procedures for interchange are not specifically regulated. The Joint Commission on Accreditation of Healthcare Organizations (JCAHO) appears to be the only source for applicable regulations regarding medical record documentation. With respect to therapeutic drug interchange, few guidelines exist to "legalize" this common practice. A procedure to provide the physician's informed consent for therapeutic interchange is explained. This article will focus on drug interchange notification procedures for non-teaching community hospitals. Legalities, practicalities, and regulations for medical record documentation are addressed. In addition, suggestions for the documentation of drug interchange are proposed.

Documentation↗
PubMed1989

The mature portion of Escherichia coli maltose-binding protein (MBP) determines the dependence of MBP on SecB for export.

The product of the secB gene is required for export of a subset of secreted proteins to the outer membrane and periplasm of Escherichia coli. Precursor maltose-binding protein (MBP) accumulates in the cytoplasm of secB-carrying mutants, but export of alkaline phosphatase is only minimally affected by secB mutations. When export of MBP-alkaline phosphatase hybrid proteins was analyzed in wild-type and secB-carrying mutant strains, the first third of mature MBP was sufficient to render export of the hybrid proteins dependent on SecB. Substitution of a signal sequence from a SecB-independent protein had no effect on SecB-dependent export. These findings show that the first third of mature MBP is capable of conferring export incompetence on an otherwise competent protein.

ATP-Binding Cassette Transporters↗
PubMed1988

Effects of Escherichia coli secB mutations on pre-maltose binding protein conformation and export kinetics.

Mutations affecting the secB gene of Escherichia coli cause a defect in protein export. This report presents the demonstration that the secB mutations caused a defect in co-translational processing of maltose binding protein (MBP). A significant amount of post-translational processing of pre-MBP occurred within 1 min after termination of pulse labeling; at later time points only a small amount of additional processing occurred. The conformation of the intracellular precursor form of MBP was examined in a secB::Tn5 mutant, using protease sensitivity (Randall, L. L., and Hardy, S. J. S. (1986) Cell 46, 921-928) as the assay. In contrast to the isogenic wild type strain, a population of pre-MBP that had folded into a protease resistant conformation was detected in the secB mutant. In addition, sublethal doses of chloramphenicol did not significantly affect protein export in the secB::Tn5 mutant and the secB::Tn5 mutation did not lead to defects in membrane energization.

ATP-Binding Cassette Transporters↗