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Biomedical subjects

S E Perry

Publications and source records attributed to S E Perry.

At least 19 recordsLinked to original sources

The clinical nurse specialist as expert witness.

A clinical nurse specialist is an ideal expert witness in cases alleging nursing negligence. Nurses choose to serve in this capacity for a variety of reasons. As an expert witness, a clinical nurse specialist may act as a consultant, review medical records, give depositions, translate medical jargon, testify in court, educate attorneys, suggest questions for attorneys to ask of witnesses, and provide opinions about the standard of care a client received. Guidelines for qualifications of an expert, reviewing medical records, preparing opinions, and testifying are given. Reactions to serving as an expert are discussed.

Consultants

The neuroscience nurse as an expert witness.

Serving as an expert witness in cases alleging nursing negligence is an interesting, rewarding and stressful role. Having knowledge about qualifications of an expert, what is expected of the expert, how to assess adequacy of nursing care, and how to bill for services may lower the stress. If after careful consideration you choose to serve as an expert witness, you should experience satisfaction knowing you are fulfilling a professional responsibility to maintain standards of care and to protect nurses accused unjustly of negligence.

Accidental Falls

Synthetic analogues of a transit peptide inhibit binding or translocation of chloroplastic precursor proteins.

Although amino-terminal transit peptides of chloroplastic precursor proteins are known to be necessary and sufficient for import into chloroplasts, the mechanism by which they mediate this process is not understood. Another important question is whether different precursors share a common transport apparatus. We used 20-residue synthetic peptides corresponding to regions of the transit peptide of the precursor to the small subunit of ribulose bisphosphate carboxylase (prSS) as competitive inhibitors for the binding and translocation of precursor proteins into chloroplasts. Synthetic peptides with sequences corresponding to either end of the transit peptide had little to no effect on binding of prSS to chloroplasts, but significantly inhibited its translocation. Synthetic peptides corresponding to the central region of the transit peptide inhibited binding of prSS to chloroplasts. Each of the peptides inhibited binding or translocation of precursors to light-harvesting chlorophyll a/b protein, ferredoxin, and plastocyanin in the same manner and to a similar extent as prSS transport was inhibited. The results presented in this paper suggest that the central regions of the transit peptide of prSS mediate binding to the chloroplastic surface, whereas the ends of this transit peptide are more important for translocation across the envelope. Furthermore, all of the precursors tested appear to share components in the transport apparatus even though they are sorted to different chloroplastic compartments.

Amino Acid Sequence

Linkage analysis of the human dopamine beta-hydroxylase gene.

The human gene for dopamine beta-hydroxylase (D beta H) has been mapped to chromosome 9q34. Using polymerase chain reaction amplification of exon 11 of the D beta H gene followed by digestion of the reaction products with FnuDII (BstUI), we detected a low-frequency restriction fragment length polymorphism (RFLP). The CEPH panel of family DNAs was genotyped for this RFLP, enabling us to determine the linkage relationships between D beta H and four other loci previously mapped to human chromosome 9q. We obtained two-point recombination frequencies (theta) between D beta H and arginosuccinate synthetase (theta = 0, LOD = 7.37), the ABO blood group locus (theta = 0, LOD = 4.5), CRI-P111 (theta = 0, LOD = 2.1), and D9S31 (theta = .06, LOD = 2.81).

Base Sequence

Dopamine beta-hydroxylase deficiency. A genetic disorder of cardiovascular regulation.

Dopamine beta-hydroxylase (DBH) deficiency is a genetic disorder in which affected patients cannot synthesize norepinephrine, epinephrine, and octopamine in either the central nervous system or the peripheral autonomic neurons. Dopamine acts as a false neurotransmitter in their noradrenergic neurons. Neonates with DBH deficiency have had episodic hypothermia, hypoglycemia, and hypotension, but survivors sometimes cope relatively well until late childhood when overwhelming orthostatic hypotension profoundly limits their activities. The hypotension may be so severe that clonic seizures supervene. Most currently recognized patients are young or middle-aged adults. The diagnosis is established by the observation of severe orthostatic hypotension in a patient whose plasma norepinephrine/dopamine ratio is much less than one.

Adult

Molecular cloning and characterization of the spaB gene of Streptococcus sobrinus.

A gene of Streptococcus sobrinus 6715 (serotype g) designated spaB and encoding a surface protein antigen was isolated from a cosmid gene bank. A 5.4 kb HindIII/AvaI DNA fragment containing the gene was inserted into plasmid pBR322 to yield plasmid pXI404. Analysis of plasmid-encoded gene products showed that the 5.4 kb fragment of pXI404 encoded a 195 kDa protein. Southern blot experiments revealed that the 5.4 kb chromosomal insert DNA had sequence similarity with genomic DNA of S. sobrinus 6715, S. sobrinus B13 (serotype d) and Streptococcus cricetus HS6 (serotype a). The recombinant SpaB protein (rSpaB) was purified and monospecific antiserum was prepared. With immunological techniques and the anti-rSpaB serum, we have shown: (1) that the rSpaB protein has physico-chemical and antigenic identity with the S. sobrinus SpaB protein, (2) the presence of cross-reactive proteins in the extracellular protein of serotypes a and d of the mutans group of streptococci and (3) that the SpaB protein is expressed on the surface of mutans streptococcal serotypes a, d and g.

Antigens, Bacterial

In vitro and ex vivo evaluation of cyclic aminoalkyl benzilates as potential emission tomography ligands for the muscarinic receptor.

A series of muscarinic antagonists were screened as potential receptor imaging agents. (+)2 alpha-tropanyl benzilate (TRB), N-methyl-4-piperidyl benzilate (NMPB) and several analogs amenable to labeling with positron emitting isotopes were evaluated for muscarinic binding to mouse brain tissue in vitro and ex vivo using [3H]quinuclidinyl benzilate as the probe. The in vitro assay directly compared the innate binding affinities of the compounds. The rank order of binding (IC50) was TRB (0.7 nm), QNB (0.8 nm), scopolamine (1.3 nm) and NMPB (1.6 nm). The ex vivo assay was used to gain information regarding the pharmacokinetics and brain penetration of the compounds in live animals. Ex vivo results demonstrated that TRB was rapidly taken up into the brain and was equipotent with QNB in occupying muscarinic binding sites at early time points, but TRB binding decreased twice as fast over time as QNB binding. The results suggest TRB would be a good candidate for radiolabeling and further study.

Animals

Calcium, sodium, and the calcium paradox.

The effect of "sodium loading," of verapamil and of nifedipine on the gain in calcium and sodium, and on the loss of myoglobin, during the calcium paradox in adult rat hearts was examined. Raising cell sodium from 56.5 +/- 2.6 to 129.5 +/- 10.2 mumol sodium/gram dry weight did not alter the degree or rate of calcium gain or myoglobin release during calcium repletion after long periods (greater than 2 minutes) of calcium-free perfusion; under these conditions, and in the presence of 10 micrograms/liter verapamil, calcium gain was enhanced. However, after shorter periods (0.5-1.5 minutes), of calcium-free perfusion, calcium gain was enhanced in "sodium-loaded" hearts, even in the absence of verapamil, and particularly during the early stages of repletion. The presence of 1 and 10 mumol/liter dl-verapamil and 1 mumol/liter nifedipine before, during, and after 10 minutes of calcium-free perfusion significantly (P less than 0.01) slowed the early (up to 1 minute for verapamil and 2 minutes for nifedipine) but not the late gain in calcium. When verapamil was present, the late gain in calcium was actually enhanced. These agents also abolished the early (45 seconds) but not the late (greater than 2 minutes) gain in sodium that occurs during repletion. We propose that the gain in calcium that occurs during calcium repletion after a period of calcium-free perfusion can be divided into at least two phases (early and late), and that the early phase contains a verapamil/nifedipine-sensitive component and a verapamil/nifedipine-insensitive component, the latter probably involving sodium-calcium exchange.

Animals

The biochemistry of uncontrolled calcium entry.

The Ca2+ paradox is characterized by a rapid and uncontrolled entry of Ca2+. Whilst the consequence of the resultant gain in Ca2+ are relatively well defined, uncertainty exists concerning the route of entry. Possible routes include passive diffusion across damaged sarcolemma and intercalated discs, active transport in exchange for K+, or Na+, and entry through the voltage-activated, Ca2+-selective slow channels. The following experiments were designed to differentiate between these possibilities. Isolated spontaneously beating Sprague-Dawley rat hearts were perfused at 37 degrees C with Ca2+-free perfusion buffer for greater than 1 min before starting Ca2+ repletion. Adding 2-4 mmol l-1 Co2+ or Mn2+ before, during but not coincident with Ca2+ repletion protected against the paradox as indicated by an absence of myoglobin release and Ca2+ overload. Despite this protection marked distortion of the glycocalyx occurred, with splitting of the basement coat and blebbing. The intercalated discs, however, remained intact. It seems unlikely therefore that splitting of the basement coat necessarily results in an uncontrolled entry of Ca2+. Since Mn2+ and Co2+ block Ca2+ entry through the slow channels their failure to prevent the uncontrolled entry of Ca2+ when added at the time of Ca2+ repletion favours the view that Ca2+ entry during the paradox does not depend upon entry of Ca2+ through the slow channels. In other experiments hearts were preloaded with Na+, to alter intracellular Na+ before Ca2+ repletion. This procedure did not markedly affect the gain in Ca2+. These findings will be discussed in terms of the route(s) and consequence(s) of the uncontrolled entry of Ca2+ that occurs when Ca2+ is reintroduced after a period of Ca2+-free perfusion.

Animals