Biomedical subjects
Publications and source records attributed to G Cimasoni.
In a group of 5 women taking oral contraceptives, the concentration of polymorphonuclear leucocytes along the gingival margin and the activities of cathepsin D, beta-glucuronidase and elastase were found to increase significantly during the intermenstrual phases.
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Most of the investigations reviewed in the present paper show that the connective tissue has an inductive potential upon epithelial differentiation. As for the investigations showing an epithelial predetermination, one must admit that they have been limited to particular tissue systems (for instance feathers and hairs) and that they could imply errors of manipulation or interpretation. As stated by Gilette: "Mesenchyme as the determinant is the favorite today, but perhaps only because experiments to demonstrate the opposite would be harder to assess" (Gilette, 1971). On the clinical point of view, one could draw an important conclusion from these investigations: at the present time, only the free or pedicle mucosal grafts including epithelium and connective tissue, or only connective tissue, are indicated to obtain a satisfactory increase of the width of attached gingiva.
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It is known that chlorhexidine, a plaque preventing agent, can cause discolorations and other side effects when used in mouthwashes at the concentration of 0.1% or more. By diluting the amount of chlorhexidine used in a mouthwash in the much greater volume of water used in a pulsating device, one could try to avoid these side-effects and, possible keep the antiplaque properties of chlorhexidine. Furthermore, it was interesting to check whether plaque, which is normally not removed by the mechanical action of a pulsating device, could be removed when the water of the device contains chlorhexidine. In the first part of the study, the effectiveness of chlorhexidine given by mouthwash (10 ml at 0.1%) has been compared to that of the same amount of chlorhexidine diluted in 400 ml of water of a pulsating device (conc. 0.0025%). The average gingival index of inflammation and plaque index, as well as the amount of gingival fluid have been measured, by previously standardized procedures, in a group of 18 students with healthy gingivae before and after a 7-days period of no-brushing. One third of the students used chlorhexidine solution in daily mouthwashes, one third used chlorhexidine in the Broxojet and the last 6 students used Broxojet with a placebo. The part of the study concerning the Broxojet was carried out in double blind. At the concentration of 0.1% in mouthwashes, chlorhexidine was found, as expected, to inhibit plaque formation. The same amount of drug diluted in the liquid of a pulsating device was, on the contrary, much less effective. Staining was noticed in most of the volunteers. The second part of the study was similarly designed and performed in the aim of checking whether higher amounts of chlorhexidine were effective in preventing plaque when used in the Broxojet: in the pulsating device, chlorhexidine was found to be effective only at the concentrations of 0.025%.
Acid and neutral protease activities were determined in the granule fractions of polymorpho and mononuclear leucocytes, separated from human blood by means of a discontinuous density gradient centrifugation. The mononuclear leucocytes contained only acid protease while preparations from polymorphonuclear leucocytes showed a predominant activity at neutral pH with a small peak in the acid range. A separation of the acid from the neutral enzyme could be obtained in the granule fraction of polymorphonuclear leucocytes by means of DEAE chomatography. The acid enzyme was then purified from a mixture of leucocytes, more than 400 times, by means of gel chromatography with Sephadex G-200 superfine. The purified acid protease showed an optimum pH of 3.6, had a molecular weight at 42 000 and was characterized by a single protein band (Rf = 0.31) by disc-gel electrophoresis. With all probability this enzyme can be classified as cathepsin D (EC 3.4.4.23).
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The activity of cathepsin D has been determined, as a function of gingival inflammation, in biopsies of human gingivae from 10 patients. The determinations have been performed both in the connective tissue and epithelium after their mechanical separation in cryostat sections. A positive and statistically significant correlation was found between the cathepsin D specific activity (as a function of either dry weight or DNA) and the degree of gingiva inflammation. These results support the hypothesis of a possible participation of lysosomal enzymes in the destruction of periodontal tissues during gingivitis and periodontitis.
In the course of the extensive tissue remodeling occurring after flap surgery and during the subsequent gingival reattachment in man, numerous intracellular vacuoles were observed in fibroblasts of the lamina propria. These vacuoles contained one or several typical collagen fibrils and had either an electron-lucent matrix or contained an electron-dense material obscuring the fibrillar outlines and cross-striations.
The gingival sulcus is formed by the space between the sulcular epithelium, the junctional epithelium, and the wall of the tooth. The functioning of its different parts is important in the early changes taking place when marginal plaque is accumulating. The cellular turnover of the junctional epithelium is very high, which could explain its high healing potential. The intercellular spaces are wider in the junctional epithelium, when compared to those of the sulcular or oral epithelia. Polymorphonuclear leucocytes can migrate through these spaces, attracted toward the sulcus by chemotactic substances. Numerous substances have been shown to permeate the junctional epithelium, both toward the sulcus and from the sulcus within the connective tissue. The sulcus is normally sterile and will tend to eliminate any foreign particle. Leucocytes and desquamated epithelial cells will also tend to leave the gingival sulcus and will be found in saliva. Various instruments, such as paper or celluloid strips of platinum loops, can be used to collect the content of the gingival sulcus. Quantitative investigations can be performed by analyzing crevicular fluid or the products of washings of the marginal gingiva.
Free gingival grafts were placed in the lower anterior vestibular region of 30 patients each of whom had a gingival recession. According to the width of the recession and to the surgical procedure, the patients were divided into four groups. Group 1 showed a "narrow" (less than 3 mm) type of recession, while Group 2 had a "wide" type. In both of these groups the graft was placed over the denuded root. In Group 3 (narrow recession) and Group 4 (wide), a collar of vestibular gingiva was left in place on the lower margin of the denuded root at the moment of grafting. Measurements and photographs taken before and 1 month after surgery, 6 months and 2 years postoperatively, showed varying degrees of root covering by the phenomenon of creeping attachment. An optimal recovery of the gingival profile was obtained in the three patients of Group 1. In the other categories of patients the creeping of the attachment apparatus was relatively small (between 0 and 33%) within the 2 years of observation. The factors which seem to have a definite influence upon the phenomenon of creeping attachment are the following: width of the recession, position of the graft, bone resorption, position of the tooth and hygiene of the patient.
A gel containing 0.2% chlorhexidine gluconate has been utilized during 6 weeks as a toothpast 3 times a day by a group of 8 students, while 8 other volonteers have brushed their teeth with a gel placebo. The gingival and plaque indices, as well as the amount of gingival fluid have been measured at the beginning and at the end of the experimental time. Colour photographs were also taken. The study, performed in double blind, did not show any significant change in the gingival conditions of the 16 students. In a second trial, the antiplaque properties of a chlorhexidine containing solution (Plak-out liquid) were tested. After thorough prophylaxis, 13 students in an experimental group and 8 students in a placebo group were asked to stop their oral hygiene procedures during 7 days and to rinse their mouth 2 times a day during 1 minute with the chlorhexidine solution or with the placebo. In each of the 2 groups, 4 subgroups were formed, each rinsing the mouth with a chlorhexidine or a placebo concentration of 0.05, 0.1, 0.15 and 0.2 per cent. In the experimental group the results show a practically complete inhibition of plaque deposits. The average plaque index, which amounted to 0.3 at the beginning of the experiment in the 2 groups, showed an increase to 1.2 in the placebo group and dropped to 0.2 in the chlorhexidine group. The plaque inhibition seems to take place as a function of the chlorhexidine concentration. The gingival index of inflammation and the amount of gingival fluid showed an increase in the placebo group but did not change in the volonteers using the active compound.
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