Biomedical subjects

D Kemp

Publications and source records attributed to D Kemp.

7 recordsLinked to original sources

PubMed1992

Sequence- and strand-specific cleavage in oligodeoxyribonucleotides and DNA containing 3'-thiothymidine.

Oligonucleotides containing a 3'-thiothymidine residue (T3's) at the cleavage site for the EcoRV restriction endonuclease (between the central T and A residues of the sequence GATATC) have been prepared on an automated DNA synthesizer using 5'-O-monomethoxytritylthymidine 3'-S-(2-cyanoethyl N,N-diisopropylphosphorothioamidite). The self-complementary sequence GACGAT3'sATCGTC was completely resistant to cleavage by EcoRV, while the heteroduplex composed of 5'-TCTGAT3'sATCCTC and 5'-GAGGATATCAGA (duplex 4) was cleaved only in the unmodified strand (5'-GAGGATATCAGA). In contrast, strands containing a 3'-S-phosphorothiolate linkage could be chemically cleaved specifically at this site with Ag+. A T3's residue has also been incorporated in the (-) strand of double-stranded closed circular (RF IV) M13mp18 DNA at the cleavage site of a unique EcoRV recognition sequence by using 5'-pCGAGCTCGAT3'sATCGTAAT as a primer for polymerization on the template (+) strand of M13mp18 DNA. On treatment of this substrate with EcoRV, only one strand was cleaved to produce the RF II or nicked DNA. Taken in conjunction with the cleavage studies on the oligonucleotides, this result demonstrates that the 3'-S-phosphorothiolate linkage is resistant to scission by EcoRV. Additionally, the phosphorothiolate-containing strand of the M13mp18 DNA could be cleaved specifically at the point of modification using iodine in aqueous pyridine. The combination of enzymatic and chemical techniques provides, for the first time, a demonstrated method for the sequence-specific cleavage of either the (+) or (-) strand.

Base Sequence↗

PubMed1990

Postoperative urinary retention: Part I--Overview and implications for the postanesthesia care unit nurse.

Postoperative urinary retention and resulting bladder distention are common complications following surgical procedures. The PACU nurse needs a thorough understanding of bladder distention, causes, and how to assess for signs and symptoms in the PACU patient. Unrelieved bladder distention can lead to discomfort and problems with micturation or chronic urinary retention. The anatomy of the bladder, causes and factors related to bladder distention, and methods with which the PACU nurse can assess and evaluate for bladder distention are presented.

Humans↗

PubMed1990

Postoperative urinary retention: Part II--A retrospective study.

Postoperative urinary retention, a potential postoperative complication, can lead to discomfort and contribute to atony of bladder wall, need for catheterization and, sometimes, prolonged hospital stays. A retrospective study was conducted to analyze variables related to postoperative urinary retention. Data was collected by a chart review of 100 postoperative cases in a large Veterans Administration Medical Center. All patients were male, had a mean age of 61.1 years, and had received spinal or general anesthesia. Patients with known urologic problems, paraplegic patients, quadruplegic patients, patients undergoing procedures lasting less than 3 hours, and patients with indwelling Foley catheters were excluded. The medical review form was used to collect data from the medical records. Sixty-one percent of the patients required straight catheterization for their first postoperative urinary output. Sixty-five percent of the spinal anesthetic patients and 57% of the general anesthetic patients required straight catheterization. Orthopedic patients were the highest percentage of patients requiring catheterization. The patients who received large volumes of intravenous (IV) fluid in the operating room were more likely to be catheterized in the PACU. Determining whether physical assessment or IV volume indicated need for catheterization of these patients was difficult because documentation on the PACU record was usually incomplete. Complete documentation of assessment and intervention on the PACU record occurred 10% of the time. A need for full assessment on all postsurgical patients in the PACU and improved documentation is indicated.

Adult↗

PubMed1989

Epithelial action potentials in embryos of the Australian lungfish.

The epithelial cells of the skin of embryonic Australian lungfish (Neoceratodus forsteri) between stages 30 and 39, are mechanosensitive and excitable, showing overshooting action potentials 400-800 ms long with a rapid rise followed by a slower repolarization (usually with a shoulder on the repolarizing phase), which propagate at around 10 mm s-1. This skin impulse system is very similar to that found in embryonic and larval Amphibia; the significance of this similarity is discussed.

Action Potentials↗

PubMed1987

An advanced cochlear echo technique suitable for infant screening.

An advanced cochlear echo test technique has been specially developed to tackle some specific problems associated with measurements from infants. The test procedure and data processing combination has greatly improved noise immunity and has given very reliable results on poorly co-operating children. Technical details are given and the results of a study of 105 ears from 55 children are presented. The potential of the advanced technique as a screening test is discussed.

Adolescent↗

PubMed1986

Primary culture of striatal neurons: a model of choice for pharmacological and biochemical studies of neurotransmitter receptors.

Striatal neurons were cultured from fetal mouse brain and maintained in serum-free medium for 14-21 days in vitro (DIV). A double coating of culture dishes with polyornithine and fetal calf serum was needed in order to obtain synaptic differentiation. Synaptic vesicles were present in axon terminals as well as in varicosities along extended axons. The presence of differentiated synapses was confirmed by the immunostaining of the preparation with synapsin I antibody. After 13 days in vitro synapsin I was present in axonal varicosities and particularly concentrated at contact points between axonal terminals and postsynaptic sites on adjacent axons or perikarya. On a surface of 429 mm2 on which 2211 cells were observed under phase contrast microscopy only 7% were stained with an antibody against GFAP (glial fibrillary acidic protein). One or two days after the formation of differentiated synapses (11 DIV), a Ca2+-dependent liberation of GABA was observed. These cultures are an excellent model for studying the coupling of some neurotransmitter receptors with an adenylate cyclase. In particular using this preparation we were able to demonstrate that dopamine (D2) and serotonin-(5-HT1) receptors are negatively coupled with an adenylate cyclase. These cultures are also an excellent model to study the coupling of some neurotransmitter receptors with inositol phosphate producing enzymes. We demonstrated for the first time that the quisqualate subtype of glutamate receptors is able to increase inositol phosphate production in striatal neurons.

Animals↗

PubMed1978

Diuretics.

Explore the source record for details and available documents.

Benzothiadiazines↗