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Biomedical subjects

A Polson

Publications and source records attributed to A Polson.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effect of personal oral hygiene on bleeding interdental gingiva. Histologic changes.

A previous study demonstrated that the combination of subgingival scaling and improved oral hygiene resulted in a reduction of clinical and histological signs of interdental gingival inflammation, changes that were associated with a cessation of interdental gingival bleeding. The present study compared, histologically, the interdental tissues of bleeding sites with sites that initially bled but had been converted to nonbleeding by an oral hygiene program alone. Morphometric analysis of interdental gingiva demonstrated that conversion from bleeding to nonbleeding was associated with a significant reduction in the inflamed connective tissue component. This study showed that an oral hygiene program consisting of toothbrushing and interdental cleaning could significantly reduce interdental inflammation, and that bleeding determinations monitored the effects of this therapy.

Adult↗
PubMed1987

Orthodontic relapse, apical root resorption, and crestal alveolar bone levels.

This investigation examined the relationship of postorthodontic treatment relapse to crestal alveolar bone support and root resorption. Thirty-six persons having completed the retention phase of orthodontics at least 10 years earlier were divided into two groups based on the amount of relapse crowding of the mandibular anterior teeth. Eighteen subjects (relapse group) exhibited 2 mm or more of mandibular anterior relapse crowding and 18 subjects (nonrelapse group) exhibited no mandibular anterior relapse crowding. At time of recall, full-mouth series of periapical and bitewing radiographs were obtained as well as lateral cephalometric films to allow comparison with similar lateral cephalometric films obtained at pretreatment and retention time points. The radiographs were examined to assess three parameters: root resorption, crestal alveolar bone levels, and changes in the position and angulation of the maxillary incisors. The subjects in the relapse group had undergone longer periods of treatment and exhibited a greater prevalence of root resorption; they also displayed significantly greater crestal alveolar bone level distances, indicating greater loss of bone support than that observed in the nonrelapse group. The distances that teeth were translated seemed to affect the extent of root resorption and crestal bone loss with smaller amounts of tooth translation seemingly more prone to demonstrate tissue loss. The findings of this investigation suggest there may be a relationship between orthodontic relapse and the parameters of increased root resorption and decreased crestal alveolar bone levels.

Adult↗
PubMed1987

A novel method of electrophoresis for the separation of individual human serum glycoproteins.

A method for the isolation of protein components by a combination of polyacrylamide gel electrophoresis and electro-extraction of slices of gel contained in cellophane dialysis tubing, using the H tube electrophoresis apparatus, is described. The method was applied to the purification of individual human serum glycoproteins. Although the glycoproteins have widely differing electrophoretic mobilities, they appeared to be antigenically interrelated judging from their complex "spurring" in Ouchterlony double gel diffusion tests.

Blood Protein Electrophoresis↗
PubMed1986

Preparation of agarose with low net negative charge density using an inexpensive anion exchanger.

A method of preparing agarose of low net negative charge density by the use of Chromium tanned gelatin is described. Using commercial agarose (agarose c) as standard of comparison the product has a sulphate content approximately 0.1 that of agarose c and its pyruvate content was reduced to zero as shown by NMR in DMSO. The product was still able to adsorb and desorb serum glycoproteins similar to agarose c indicating that charge on the agarose c gel particles played a minor role if any on the binding of the serum glycoproteins.

Adsorption↗
PubMed1986

Interproximal gingival inflammation related to the conversion of a bleeding to a nonbleeding state.

Elimination of gingival bleeding has been related to a reduction in inflammation; however, histologic data are not available to support this association. The purpose of this study was to characterize the histology of interproximal gingiva that was converted from a bleeding to a nonbleeding state. An interproximal gingival biopsy was obtained from each of 32 patients, 15 of whom bled upon stimulation with a soft wooden interdental cleaner. The remaining 17 biopsies were obtained from sites which initially bled, but were converted to nonbleeding by scaling and interproximal plaque control. Specimens were processed for light microscopic evaluation and subjected to a morphometric analysis for various tissue components. Data from bleeding and "stopped bleeding" specimens were compared using analysis of covariance. The results indicated that "stopped bleeding" specimens had significantly less inflamed connective tissue. It was concluded that the conversion of a bleeding to a nonbleeding state corresponds with a histological reduction in the magnitude of the interproximal inflammatory lesion and provides a rationale, therefore, for the use of bleeding to monitor the effects of therapeutic methods.

Adult↗
PubMed1985

An apparatus for the concentration of large volumes of dilute protein solutions to a predetermined volume.

An apparatus was designed and manufactured that can be used for the concentration of large quantities of dilute protein solutions to a predetermined volume. The method is based on the osmotic transfer of water to a concentrated hydrophilic polymer (poly ethylene glycol, PEG) through a protein-stopping dialysis membrane and is a refinement of a method previously reported by van Oss. The apparatus is made of perspex. Concentration takes place through a commercially available dialysis tube and is aided by a 40% polyethylene glycol solution. Large volumes (5l) of dilute protein solution could be reduced to 50 ml at a rate of 30 ml per hour with no significant loss in biological activity.

Animals↗
PubMed1985

Microscopic monitoring of pathogens associated with periodontal diseases. A review.

Microscopic monitoring of the subgingival microbiota to detect pathogens associated with periodontal diseases has been an active area of investigation. Researchers have demonstrated that plaque samples obtained at diseased sites contain more motile bacteria and less coccoid forms than healthy sites. Therapy at diseased locations has resulted in a shift in the microbiota to one that resembles healthy sites. However, the ability to predict disease activity based on morphotype counts still remains unverified. The current literature addressing chairside microscopic assessments as a diagnostic parameter is reviewed and discussed.

Bacteria↗
PubMed1985

Coated glass beads in enzyme linked immunosorbent assays.

Successful enzyme linked immuno-sorbent assays (ELISA) were conducted with frosted glass beads coated directly with an immune reactant (antigen or antibody) using glutaraldehyde as cross linking agent. Equally effective ELISA experiments were made by attaching the antigen to a thin layer of gelatin which had been cross-linked over the entire surfaces of the frosted glass beads. The enzyme and substrate used were alkaline phosphatase and p-nitro-phenyl phosphate.

Alkaline Phosphatase↗
PubMed1984

Agarose: a possible universal gel exclusion agent.

Granulated agarose gels suitable for gel exclusion chromatography of proteins of any molecular weight may now be prepared. This was made possible by the observation that agarose solutions of 16% polysaccharide may be prepared by displacing 8% agarose from solution with 8% polyethylene glycol Mr 6000. The displaced polysaccharide concentrates in a viscous mass occupying half the volume of the original carbohydrate solution. By diluting the displaced polysaccharide with hot watery solutions of electrolyte and allowing the solutions to congeal, gels of any desired concentration, ranging from low to the maximum of 16%, may be prepared.

Animals↗
PubMed1984

Bead centrifuge tube inserts--a semi-quantitative theory.

A semi-quantitative theory is proposed for the sedimentation of particles in centrifuge tubes filled with polymer beads acting as sedimentation aids. The theory concerns the attainment of approximate sedimentation-diffusion equilibrium in minimum time of centrifugation. It is shown empirically that the time to reach this state is approximately proportional to the diameter of the polymer beads as predicted by the theory.

Diffusion↗
PubMed1984

Histologic comparisons of interproximal gingival tissues related to the presence or absence of bleeding.

Interproximal gingival tissues were compared histologically relative to the presence or absence of bleeding after stimulation with a wooden interdental cleaner. Fifteen bleeding and 15 nonbleeding interproximal gingival biopsy specimens were obtained from 30 patients and processed for light microscopic evaluation. Morphometric analysis of tissue components revealed that bleeding areas had a significantly greater per cent of inflamed connective tissue. The inflammatory lesion in the bleeding specimens was primarily in the midinterproximal area. From a diagnostic standpoint, this information provides a rationale for the use of bleeding to detect inflammatory lesions in the midinterproximal region.

Adult↗
PubMed1984

Periodontal response after tooth movement into intrabony defects.

The present study was undertaken since conflicting evidence exists regarding the effect of such tooth movement on levels of connective tissue attachment. Localized intrabony pockets were produced around isolated incisors in four rhesus monkeys. The root surfaces were planned to the level of the bone at the base of the angular bony defects. An oral hygiene regime was begun and continued for the remainder of the study. The experimental teeth were moved orthodontically into, and through, the original area of the intrabony defect. Two months after cessation of active tooth movement, block specimens were removed for histologic analysis. Control specimens comprised those teeth with induced periodontal defects, but without tooth movement. In specimens not subjected to tooth movement, angular bony defects were present and epithelium lined the root surface to the apical extent of instrumentation. The alveolar bone adjacent to the orthodontically moved teeth no longer had angular defect morphology. On the pressure side, epithelium lined the root surface, was interposed between root surface and bone and terminated at the apical limit of root instrumentation. On the tension side, the crest of the bone was located apical to the level of root planing, and epithelium lined the instrumented portion of the root surface. It was concluded that orthodontic tooth movement into intrabony periodontal defects was without effect upon the levels of connective tissue attachment.

Alveolar Process↗
PubMed1983

Novel application of H tube electrophoresis to separation technology.

The H tube electrophoresis technique was used for isolating human IgG by the net effect of electrophoresis and electro-endosmosis in agarose gel containing human serum. In a similar experiment human serum albumin was purified by extracting the agarose gel slice containing the albumin following zone electrophoresis of serum in agarose. By taking advantage of the relatively high reverse electro-endosmotic flow compared to the migration of IgG in agarose gel, sheep anti chicken immunoglobulin was fractionated into active and inactive portions. It was estimated that 90% of the nonspecific IgG could be eliminated in this manner. The specific immunoglobulin fraction showed a higher mobility to the positive electrode than the bulk of the non specific IgG. The H tube proved to be ideal for zone electrophoresis in concentration gradients of inert substances. For this purpose sugar gradients were used for electrophoretic separation of proteins and viruses which are not affected by high osmotic pressures but, for separating animal cells it was necessary to use Ficoll gradients. A mixture of yellow Atypical Tomato Mosaic Virus and the haemocyanin of Burnupena cincta were separated into discrete zones and chicken IgY anti haemocyanin was subfractionated. The specific fraction showed a lower migration rate to the positive pole than the bulk of the non specific material.

Animals↗