Biomedical subjects

L A Howard

Publications and source records attributed to L A Howard.

31 records · Page 2Linked to original sources

PubMed1990

Nonradioactive nucleic acid detection by enhanced chemiluminescence using probes directly labeled with horseradish peroxidase.

The use of nucleic acid probes directly labeled with horseradish peroxidase for detection of single copy sequences on Southern blots of human genomic DNA by enhanced chemiluminescence is described. Of the target sequences, 6 x 10(5) molecules (1 amol) have been detected on blue sensitive film using exposures of up to 60 min and probes of 0.3-5.1 kb. The chemiluminescent signal quantified using a cooled charge coupled device (CCD) camera is proportional to probe length for DNA probes in the range 50-3571 bases. The enzyme has no significant effect on the stability of a DNA/DNA hybrid formed with a 3571-base probe and target as determined by increasing the stringency of posthybridization washes by decreasing the concentration of a monovalent cation (NaCl) and by a Tm analysis. The kinetics of DNA hybridization have been analyzed by a cooled CCD camera to provide quantitative data. Ten nanograms per milliliter of probe may be used for an overnight hybridization. Southern blots can be reprobed using a DNA probe for the same or a different sequence without the necessity of stripping off the previously bound probe.

Blotting, Southern↗

PubMed1990

Effects of 2% lignocaine on somatosensory evoked potentials recorded in the extradural space.

We have studied the effects of extradural administration of 2% lignocaine at the L3-4 interspace on somatosensory evoked potentials recorded in the cervical extradural space before corrective surgery for idiopathic adolescent scoliosis. Eight patients in whom the equivalent volume of 0.9% sodium chloride solution was administered into the lumbar extradural space acted as a control group. Lignocaine 2% resulted in a decrease in overall amplitude, but its main effect was a significant decrease in the amplitude of the second and third peaks, suggesting an action on the dorsal columns of the spinal cord. A significant increase in latency was found in both the lignocaine and sodium chloride groups. We conclude that the use of extradural 2% lignocaine in patients undergoing scoliosis surgery may interfere with the intraoperative monitoring of somatosensory evoked potentials.

Adolescent↗

PubMed1989

Construction of cloning/sequencing vectors with an alternative polylinker.

This paper describes the construction of a new plasmid and M13 phage cloning vector in which the 54-bp polylinkers of pUC19 and of M13mp8 are replaced with a 45-bp chemically synthesized polylinker with different restriction sites. The new polylinker is inserted in frame at the N-terminal end of the beta galactosidase lac Z fragment. The plasmid was named pLH1, the phage M13LH1.

Bacteriophages↗

PubMed1988

Use of glycosyltransferases to restore pertussis toxin receptor activity to asialoagalactofetuin.

Fetuin derivatives with enzymatically altered oligosaccharide units were tested for their ability to inhibit pertussis toxin-mediated agglutination of goose erythrocytes and the binding of 125I-labeled fetuin to pertussis toxin-coated polystyrene tubes. Fetuin oligosaccharides were sequentially degraded by treatment with: neuraminidase (asialofetuin) followed by beta-galactosidase (asialoagalactofetuin) and, lastly, with beta-N-acetylhexosaminidase (asialoagalacto-a[N-acetylglucosamino]fetuin). Asialofetuin retained only 19 and 53% of the inhibitory activity of native fetuin in the hemagglutination and 125I-fetuin binding assays, respectively. Asialoagalactofetuin showed no further reduction of inhibition in the hemagglutination system and, instead, resulted in partial recovery of inhibition in the 125I-fetuin-pertussis toxin binding assay. Asialoagalacto-a[N-acetylhexosamino]fetuin showed a further decrease in ability to inhibit pertussis toxin binding in both assays. The inhibitory activity of asialoagalactofetuin could be restored to that of native fetuin by adding back D-galactose with UDP-Gal:D-glucosyl-1,4-beta-galactosyltransferase, followed by the addition of terminal sialic acid residues with CMP-N-acetylneuraminic acid:beta-D-galactosyl-1,4-N-acetyl-beta-D-glucosamine-alpha-2,6-N- acetylneuraminyltransferase. The data suggested that a requirement for pertussis toxin binding to fetuin may be the presence of acetamido-containing sugar groups in the nonreducing terminal position of fetuin's oligosaccharides.

Animals↗

PubMed1987

Effect of carbohydrates on growth of Ureaplasma urealyticum and Mycoplasma hominis.

We examined the effect of 31 carbohydrates on the growth of Ureaplasma urealyticum and Mycoplasma hominis. Arbutin and its breakdown product, hydroquinone, inhibited growth of both species; the other substrates did not alter the extent of growth. Volatile and nonvolatile end products of carbohydrate metabolism were not detected by gas chromatography.

Arbutin↗

PubMed1975

Mental health ideologies of psychiatric nurses.

Students in graduate programs of psychiatric nursing across the United States were surveyed in terms of their individual commitment to three major mental health ideologies--community mental health ideology, psychotherapetic ideology, and somatotherapeutic ideology. In contrast to earlier research, which had indicated that psychiatric nurses are ideologically neutral, it was found in the present study that as a group these 386 young psychiatric nurses were more committed to community mental health ideology than to the other two psychiatric orientations measured.

Attitude of Health Personnel↗

PubMed1971