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Biomedical subjects

G Cimasoni

Publications and source records attributed to G Cimasoni.

At least 19 recordsLinked to original sources
PubMed1992

An in vitro study of polymorphonuclear leucocyte-mediated injury to human gingival keratinocytes by periodontopathic bacterial extracts.

Human gingival keratinocytes were cultured and, after the first passage, subjected to cell detachment assays with polymorphonuclear leucocytes (PMNs) and/or sonic extracts from Actinobacillus actinomycetemcomitans Y4, and Eikenella corrodens 1073. The effector-to-target cell ratio was 30:1. Bacterial extracts alone caused no disruption of keratinocyte monolayers. PMNs alone also caused only minimal detachment after 14 h incubation. Adding A. actinomycetemcomitans to the PMN-keratinocyte co-cultures at the concentration of 100 micrograms/ml caused dramatic cell detachment. The effect of A. actinomycetemcomitans was heat labile and not inhibited by polymyxin B. Cell detachment was inhibited by alpha 1-antitrypsin, whereas catalase and superoxide dismutase could not prevent it. No lysis of keratinocytes was observed after incubation, as judged by 51Cr release. E. corrodens had little effect even at the concentration of 1000 micrograms/ml. H2O2 and partially purified PMN elastase also caused detachment of keratinocytes. These data indicate that PMNs can cause non-lytic detachment of keratinocytes when interacting with certain bacteria.

Aggregatibacter actinomycetemcomitans↗
PubMed1992

Neutrophil elastase and its inhibitors in human gingival crevicular fluid during experimental gingivitis.

The relative concentrations and absolute amounts of neutrophil elastase and its two inhibitors, alpha 2-macroglobulin (alpha 2-M) and alpha 1-antitrypsin (alpha 1-AT), were determined in gingival crevicular fluid (GCF) collected from six dental students who refrained from brushing the upper left or right quadrant during three weeks. Plaque and gingival indices and flow of GCF were measured before, during, and after the three weeks of no brushing. Functional elastase, representing the enzyme complexed with alpha 2-M, was measured by use of a low-molecular-weight fluorogenic substrate. Elastolytic activity in GCF was also assayed by use of elastin as substrate. Antigenic elastase, representing the enzyme complexed with alpha 1-AT, as well as the inhibitors alpha 2-M and alpha 1-AT were measured by ELISA. After three weeks of plaque accumulation, the concentrations of both functional and antigenic elastase increased by a factor of about 3, whereas the concentrations of the inhibitors increased in a much higher proportion. No free elastase could be detected in GCF, as evidenced by the Sephadex G-75 elution profile of GCF, by the negative results obtained when elastin was used as substrate, and by the demonstration that pure enzyme kept its activity against the low-molecular-weight substrate after being saturated by alpha 2-M.

Adult↗
PubMed1992

Comparison of photodensitometric with high-resolution digital analysis of bone density from serial dental radiographs.

Photodensitometry is known to provide high spatial resolution and continuous measurement of optical density for the analysis of dental radiographs, whereas digitization allows powerful image manipulations but, when using conventional video cameras, gives less spatial resolution and fewer grey levels. The aim of this study was therefore to develop a technique of high-resolution digital analysis for the measurement of bone density following the same principles as those of photodensitometry and based upon the use of a CCD Scanner Camera which provides up to 4096 grey levels and a spatial resolution of 4096 x 4096 pixels. Twenty-four zones were analysed with both techniques in five serial dental radiographs taken before and after periodontal therapy in eight patients. Statistical comparison of the results obtained by digital analysis and photodensitometry shows that the two techniques have the same accuracy.

Absorptiometry, Photon↗
PubMed1991

In vitro release of elastase from human blood and gingival crevicular neutrophils.

Peripheral PMNs were collected from blood, and crevicular PMNs separated by filtration from gingival washings in 13 patients, aged 22-75 y, who had varying degrees of gingivitis and periodontitis. After pre-incubation with cytochalasin B, the same number of crevicular and peripheral cells were incubated either in PBS (with Ca2+ and Mg2+) (spontaneous release) or in the same buffer containing increasing concentrations of FMLP (stimulated release); elastase activity was measured in the supernatant by a fluorometric technique. There was a higher spontaneous release of enzyme from crevicular than from peripheral neutrophils. The average elastase activity in the supernatant of 1 x 10(4) crevicular cells was more than five times higher than that obtained from the same number of peripheral cells. However, stimulated crevicular PMNs liberated smaller amounts of enzyme than did stimulated peripheral PMNs. These results suggest that crevicular PMNs are already releasing elastase, and are consistent with the possibility that lysosomal enzymes contribute to tissue damage during gingivitis and periodontitis.

Adult↗
PubMed1991

[Dentin hypersensitivities and their treatment. A review of the literature].

Dentin hypersensitivity is a painful manifestation resulting from a response of the openings of dentin tubules to oral environment. It is probably caused by movements of intratubular fluids, under the influence of different types of stimuli at the dentin surface. Hypersensitivity has been known for a long time and its treatment has always been difficult. Sometimes, by a kind of natural reaction to aggression, dentin is able to increase its degree of mineralisation but, most of the time, an active treatment has to be performed. Unfortunately the mechanism of dentinal pain is not well known and the symptoms of sensitivity are unspecific and subjective, so that the ideal compound for treatment does not exist. Many products have been tested, but the results are most of the time contradictory and the placebo effect is often very significant. In all cases the aim of the treatment remains the obliteration of dentin tubules, in order to obtain a decrease of dentin permeability.

Dental Plaque↗
PubMed1990

Synthesis of alpha 2-macroglobulin in human gingiva: a study of the concentration of macroglobulin and albumin in gingival fluid and serum.

Albumin and alpha 2-macroglobulin were analysed in gingival fluid collected by filter paper strips from 6 volunteers before, during and after 10 days of dental plaque accumulation. The two proteins were also determined in samples of venous blood at the beginning of abstention from tooth brushing and 10 days later. A nephelometric technique was used for the analysis of albumin, but alpha 2-macroglobulin was determined by ELISA. The plaque and gingival indices, as well as the flow of gingival fluid, increased significantly during the period of plaque accumulation and then returned to baseline values. The concentrations of the two proteins in blood remained within normal limits. In gingival fluid, however, the concentration of albumin increased about two-fold at the peak of inflammation, while that of alpha 2-macroglobulin increased as much as 6 times. The enhanced passage of alpha 2-macroglobulin into the gingival sulcus in comparison to the entirely plasma-derived albumin was consistent with the concept that the greater excretion of globulin during inflammation must be due to an increased local synthesis.

Adult↗
PubMed1990

Increase of interproximal bone density after subgingival instrumentation: a quantitative radiographical study.

Ten interproximal sites, with periodontal pockets deeper than 5 mm and showing loss of bone on standard dental radiographs, were treated by subgingival instrumentation in 10 patients properly motivated and given thorough hygiene instructions. The index of gingival inflammation, the plaque index, the degree of mobility, the depth of the pockets, and the loss of attachment were measured before starting the treatment, and 2 months, 6 months, and 1 year after treatment. Standardized reproducible radiographs of the 10 sites were taken by using a recently developed paralleling instrument before treatment, immediately after and 2 months, 6 months, and 1 year afterwards. The density of the interdental bone was measured on the radiographs by a computer assisted densitometric technique at three levels of the interdental septum: the most occlusal or "superficial" level; the "deep" level, arbitrarily chosen 1.5 mm below; and the "control" level, in a much deeper area of interproximal bone. As further control, the density of the superficial crestal bone was also followed in 5 healthy untreated sites from 5 of the patients. As expected, a significant improvement of the clinical parameters was observed during the year following therapy. The results of the radiographical analysis showed statistically significant increases of both the superficial and deep average densities of interproximal bone at 6 months and 1 year after treatment. The superficial bone density was, on the average, 13% higher at 6 months and 16% higher at 1 year, as compared to that measured immediately after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1988

In-vitro synthesis of alpha 2-macroglobulin by human gingival fibroblasts.

Cells from explants were cultured in the presence of [L-35S]-methionine for 24 h. Cultures containing cycloheximide or cultures frozen immediately after addition of labelled methionine served as controls. The medium was removed and, after washing, cells were disrupted by repeated freezing and thawing. Synthesis of alpha 2-macroglobulin (alpha 2-M) was evaluated by autoradiography of the SDS-PAGE patterns obtained with the culture medium, and by autoradiography of the crossed immunoelectrophoretic patterns obtained with both the cell extract and the culture medium. There was incorporation of labelled methionine in newly-synthesized alpha 2-M. No autoradiographic bands were found in the frozen preparations, and there was a progressive inhibition of globulin synthesis in the presence of increasing concentrations of cycloheximide. This synthesis of alpha 2-M by human gingival fibroblasts may explain the presence of free alpha 2-M in gingival fluid and might be of significance in the control of proteolysis during gingivitis and periodontitis.

Cells, Cultured↗
PubMed1988

A simple paralleling instrument for superimposing radiographs of the molar regions.

A simple, disposable paralleling device to produce identical radiographs of the maxillary and mandibular molar regions is described. Its precision was determined by taking serial radiographs of several patients. No deformations were found when enlargements of the radiographs were made. Identical tracings were produced during analysis with a computer-assisted densitometric technique. The new device is inexpensive and could be used advantageously for qualitative and quantitative longitudinal studies.

Humans↗
PubMed1987

Densitometric analysis of lower molar interradicular areas in superposable radiographs.

Superposable radiographs of lower molar areas were obtained by means of a specially designed film holder and a gnathostat maintained in a constant position with respect to long-cone radiological equipement. A quantitative evaluation of the bone mass in the interradicular area was obtained by scanning the area under a photodensitometer. A photodensitometric scan of the image of an aluminium wedge adapted to each radiograph was also performed. This allowed the transformation, with the aid of a computer, of the photodensitometric recording of bone into a tracing of mm of aluminium equivalents. The reproducibility and precision of the method were verified by comparing magnifications of repeated radiographs, by photodensitometric readings of radiographs developed in different batches and by repeated quantitative readings of the same film. The method allowed one, for instance, to follow quantitatively the healing of a radiographically visible periapical lesion. It was also used to evaluate quantitatively, in the interradicular area, bone changes which could not be seen with the marked eye.

Densitometry↗
PubMed1987

Longitudinal quantitative radiodensitometric study of treated and untreated lower molar furcation involvements.

38 first or second lower molars from 16 patients showing furcation involvements of degrees 1 and 2 were treated after motivation and hygiene instruction, either by subgingival curettage, or by the modified Widman surgical procedure or by furcation plasty. The plaque index, the gingival index of inflammation and the depth of interproximal and interradicular pockets were recorded before and up to 1 year after the 3 therapeutical procedures. The above clinical indices were also followed for 2 years in 15 lower molars from 7 untreated patients. A quantitative radiographical analysis of the interradicular bone was performed in all patients, by using superposable identical radiographs and a computer-assisted photodensitometric technique. In the 3 groups of treated patients, the clinical scores were, in general, improved by the 3 therapeutic modalities. In the furcation areas, the plaque index was always higher on the lingual side, whereas the depth of "horizontal" pockets was always greater on the buccal side. Except for the lesions treated by furcation plasty, no change could be noticed clinically in the depths of vertical or horizontal penetration of a periodontal probe in the furcation areas. The quantitative radiographic analysis, however, clearly showed a loss in the first 2 mm of superficial bone during the 2 months following the 3 therapeutical procedures: this loss was followed by a statistically significant recovery and, for the group treated by curettage, even by a net gain during the 6 to 12 months following therapy. The radiographical density of the deeper layer of bone did not change in the group treated by curettage only. It showed a loss in the first 2 months following the 2 surgical procedures but a statistically significant recovery in the months thereafter. As for the group of untreated patients, at the examinations performed initially, 6 months, 1 and 2 years later, the number of plaque-free and non-bleeding sites in the furcation areas was lower on the lingual as compared to the buccal side, whereas the frequency distribution of furcation involvements was similar on both aspects. No significant changes were found in the various clinical parameters throughout the 2 years of the study. On the contrary, a significant loss of average density of the superficial layer of interradicular bone was already measured on the superposable radiographs 6 months after the initial examination and was found to increase thereafter. No changes of radiodensity could be measured for the deeper layer of bone.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

Effect of crevicular fluid and lysosomal enzymes on the adherence of streptococci and bacteroides to hydroxyapatite.

Samples of hydroxyapatite (HA) beads smaller than 1 mg were coated with 10 microliter of either saliva, serum, or human crevicular fluid before being added to a suspension of Streptococcus sanguis or Bacteroides gingivalis. In some assays, preparations of a granular fraction, elastase, or cathepsin G from human leukocytes were used to coat HA or to treat saliva-coated HA (SHA) before mixing with bacteria. The number of cells adhering to the beads was then counted under a scanning electron microscope by a standardized procedure. More cells were found to adhere to SHA in this assay than in the conventional large-scale assay. Human crevicular fluid, even when diluted up to three times, completely inhibited the adherence of S. sanguis to HA. A 100% inhibition of S. sanguis adherence was also observed when HA was coated with the granular fraction of leukocytes, and a 65% inhibition observed when SHA was treated with the enzyme preparation. When used to coat HA, elastase and cathepsin G reduced the adherence of S. sanguis by 30 and 50%, respectively. The binding of S. sanguis to elastase- or cathepsin G-treated SHA was also reduced. B. gingivalis 33277 was found to adhere in high numbers to SHA. Coating HA with crevicular fluid or with the lysosomal enzyme preparation had a limited negative effect. We postulate that crevicular fluid prevents the adherence of S. sanguis by virtue of either its enzyme content or its albumin content or both.

Bacterial Adhesion↗
PubMed1987

Adherence of Treponema denticola to modified hydroxyapatite.

Small samples of hydroxyapatite (HA) beads were coated with 10 microL of either saliva, serum, human crevicular fluid, or a preparation of lysosomal enzymes from human polymorphonuclear leucocytes (PMN), before being added to suspensions of Treponema denticola. The beads were then observed with the scanning electron microscope. Abundant T. denticola were found to adhere to HA or HA coated with saliva, serum, or crevicular fluid. Coating the beads with lysosomal enzymes consistently prevented the adhesion of T. denticola. Adhesion of treponemes to hard surfaces, modulated by enzymes from PMNs, could represent a new virulence factor for these bacteria.

Bacterial Adhesion↗
PubMed1985

Flow and albumin content of early (pre-inflammatory) gingival crevicular fluid from human subjects.

Gingival fluid was collected with glass capillaries tubing from the upper premolar area in a group of 7 volunteers, after allowing dental plaque to accumulate for 12-36 h, and in a group of patients with gingivitis. Whereas no fluid could be collected in the absence of plaque, increasing amounts were recovered during plaque accumulation, in the absence of clinical signs of gingival inflammation. The ratios of albumin concentrations in gingival fluid and plasma also increased significantly with increasing time of plaque accumulation. These fluid:plasma ratios of albumin concentrations were significantly lower than the ratios found for the inflamed sites in the second group of patients. These results support the hypothesis that, in an early inflammatory response, the fluid is not a typical inflammatory exudate and is probably modulated by an osmotic gradient.

Adult↗