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Biomedical subjects

J S Reid

Publications and source records attributed to J S Reid.

At least 55 records · Page 3Linked to original sources
PubMed1991

The effect of bonding agent and fissure sealant on microleakage of composite resin restorations.

The purpose of this study was to assess, in vitro, the microleakage of Class V composite resin restorations following sealing of the margins with a fissure sealant or the resin component of a dentinal bonding agent, and to compare it to the microleakage of an unsealed control group. All groups of teeth showed some degree of leakage at the gingival margin. Statistical analysis showed that there was significantly less leakage when the fissure sealant (P less than .01) and bonding agent (P less than .001) were used than there was in the control group, in which the margins had not been sealed. There was no statistically significant difference between the two experimental groups. There was no leakage at the enamel margin in any of the teeth.

Bicuspid↗
PubMed1990

Etch-retained porcelain laminate bridges.

The technique of using etch-retained porcelain laminate bridges to restore missing teeth in anterior short-span gaps is described. The advantages and disadvantages that these bridges have in relation to other etch-retained bridges are discussed. Clinical cases are shown to highlight the improved aesthetic results obtained when using these bridges. The ability to choose a labial path of insertion not only gives improved aesthetics but offers the opportunity of treating patients unsuitable for bridges requiring a lingual path of insertion. Although the clinical technique is straightforward it requires a knowledge of basic bridge principles and etched porcelain procedures. The early results are encouraging and as the technology advances hopefully so will the results.

Acid Etching, Dental↗
PubMed1988

A beta-D-galactosidase from nasturtium (Tropaeolum majus L.) cotyledons. Purification, properties, and demonstration that xyloglucan is the natural substrate.

beta-D-Galactosidase activity has been detected previously in the cotyledons of germinated nasturtium (Tropaeolum majus L.) seeds and has been linked to the hydrolysis in vivo of storage xyloglucan (amyloid) (Edwards, M., Dea, I. C. M., Bulpin, P. V., and Reid, J. S. G. (1985) Planta (Berl.) 163, 133-140). The major beta-D-galactosidase present in extracts from the cotyledons of 9-day seedlings has now been purified to apparent homogeneity. The enzyme (Mr 97,000, no subunits) comprised a range of closely related molecular species ranging in isoelectric point from pH 6.6 to 7.1. Further purification to give a single protein band on isoelectric focusing (pI = 7.1) was achieved by chromatofocusing. The pH optimum of the enzyme (mixed molecular species) was 4.0-5.0 (stable from pH 3-10), and the temperature optimum was 50 degrees C (stable to 50 degrees C). It hydrolyzed lactose and beta-D-galactopyranosides but not melibiose and alpha-D-galactopyranosides. It did not release the terminal nonreducing alpha-D-galactopyranosyl residues from seed galactomannans, but catalyzed the rapid removal of terminal nonreducing beta-D-galactopyranosyl residues from xyloglucans. On the basis of the ability of the enzyme to hydrolyze xyloglucans, the kinetics of xyloglucan hydrolysis, and an experimental demonstration of a clear correlation between xyloglucan depletion and the activity in vitro of this enzyme, it is argued that the cell-wall storage xyloglucan of the nasturtium seed is its natural substrate.

Galactosidases↗
PubMed1986

Purification and properties of a novel xyloglucan-specific endo-(1----4)-beta-D-glucanase from germinated nasturtium seeds (Tropaeolum majus L.).

Endo-(1----4)-beta-D-glucanase activity has previously been detected in the cotyledons of germinated nasturtium (Tropaeolum majus L.) seeds, and has been linked to the hydrolysis in vivo of storage xyloglucan (amyloid) (Edwards, M., Dea, I. C. M., Bulpin, P. V., and Reid, J. S. G. (1985) Planta (Berl.) 163, 133-140). Extracts from the cotyledons of 14-day seedlings are now shown to contain a single endo-glucanase activity, and it has been purified to apparent homogeneity by sequential anion-exchange chromatography, cation-exchange chromatography, and gel filtration. The purified enzyme gave a single protein band on polyacrylamide gel electrophoresis, dodecyl sulfate gel electrophoresis, and isoelectric focusing. The isoelectric point was 5.0, the pH optimum 4.5-5.0, and the temperature optimum 40 degrees C. Dodecyl sulfate electrophoresis gave a molecular weight of 29,000; permeation methods gave lower values. The enzyme contained about 5% carbohydrate. An endo mode of action on tamarind seed xyloglucan was deduced by monitoring solution viscosity and reducing power, and by analyzing the end products of the reaction. The specificity of the enzyme toward a wide range of substrates, including celluloses, carboxymethyl and hydroxyethyl celluloses, glucomannan, galactoglucomannans, mixed-linkage (1----3 and 1----4)-beta-D-glucan, laminarin, and xyloglucans from seeds and primary cell walls, was tested. Only the xyloglucans were hydrolyzed. It is concluded that the enzyme is a pure, endo-acting (1----4)-beta-D-glucanase which is novel in its apparently complete specificity toward xyloglucans. It is speculated that enzymes of this type may have escaped earlier detection because it is normal practice to screen for endo-(1----4)-beta-D-glucanase using artificial cellulose derivatives and that they may be widely involved in xyloglucan metabolism in plant cell walls.

Cellulase↗
PubMed1986

Can a patient register be accurate in New Zealand?

A study of the patient register at Kopata Medical Centre, was undertaken to determine its accuracy. A 10% sample gave an inflation rate of 4.2% and an overall accuracy of 92.4%. There had been a great improvement in the accuracy over the last seven years and we conclude this is mainly due to considerable use of the register for patient recall.

Child↗
PubMed1984

Childhood immunisations: a recall system is worthwhile.

In this prospective study of 416 children in a computerised immunisation recall system, 78% attended voluntarily. A further 16% attended with prompting and of the remainder the majority are being followed up by the public health nurses. The system identifies individual children who have missed out on a specific immunisation and enables the omission to be corrected close to the most appropriate time. Sixty-seven children who were omitted were subsequently immunised in the sixth month period studied.

Child, Preschool↗
PubMed1984

Thermally induced bone necrosis in rabbits. Relation to implant failure in humans.

The exposure of bone to high temperatures has become quite common, especially with the increasing use of polymethylmethacrylate (PMMA) bone cement. With particular regard to total hip arthroplasty, many authors have commented on the temperature problem induced by the curing PMMA cement mass. Polymerization temperatures at the bone-cement interface have been measured and range between 40 degrees and 110 degrees, depending on the thickness of the cement line. Thermal bone damage is implicated as a significant cause of early loosening of implanted joint prostheses. The authors designed a fluid probe to deliver heated isotonic fluid directly over exposed cortical bone on a rabbit's proximal tibia. Scald temperatures ranged from 45 degrees-90 degrees for a standard exposure time of one minute. Bone tissue samples taken at intervals of one, two, and three weeks postoperatively were used to establish the thermal-damage threshold for living bone and assess regeneration potential. Controls were included to observe the reaction of bone to the surgical procedure. Bone necrosis was consistently seen in histologic sections at scald temperatures greater than or equal to 70 degrees. Although an inflammatory reaction replaced by a fibrous tissue scar was seen at the site of surgically damaged periosteum, no control animals showed evidence of either bone or marrow necrosis. These results led the authors to suggest that joint replacement systems in human bone, using PMMA bone cement, be designed to limit intraoperative temperature maximums to a level less than 70 degrees. By preventing excessive bone necrosis at the bone-cement interface, early loosening and subsequent implant failure may be significantly reduced.

Animals↗
PubMed1978

Deposits of immunoglobulin and complement in the pulmonary tissue of patients with "heroin lung".

Pulmonary tissues from six patients who died with a clinical diagnosis of "heroin lung" (heroin-induced pulmonary edema) were examined with the light microscope and electron microscope. Immunofluorescent microscopic analysis revealed multifocal granular alveolar septal deposits of IgM in all patients, C3 complement in five patients, IgG in four patients, fibrinogen in three patients, and IgA in two patients. IgM, IgG, IgA, and C3 complement were eluted from the lungs of these addicts with citrate buffer with a low pH. No deposition of albumin was found in any of the specimens. These findings are believed to represent the first report of immune complexes in the alveolar capillary membrane in patients with heroin-induced pulmonary edema. Electron-microscopic studies revealed a proteinaceous plasma-like fluid in the alveolar spaces, thereby confirming the heroin induced pulmonary edema. Mechanisms of transport of edematous fluids from alveolar capillaries to alveolar spaces in lungs from heroin addicts are considered.

Adult↗
PubMed1977

Investigations into black extrinsic tooth stain.

An investigation has been carried out into the nature of the black pigment in black extrinsic tooth stain. The results suggest that the black material is a ferric salt, probably ferric sulfide, formed by the reaction between hydrogen sulfide produced by bacterial action and iron in the saliva or gingival exudate.

Adolescent↗