Biomedical subjects

M Jontell

Publications and source records attributed to M Jontell.

At least 37 records · Page 2Linked to original sources

PubMed1998

Fluconazole versus nystatin in the treatment of oral candidosis.

The efficacy of oral fluconazole versus nystatin was evaluated as a treatment modality for oral candidosis. Of the included patients (n = 60), two-thirds presented with an erythematous candidosis, and the others showed clinical signs compatible with a pseudomembranous candidosis. Predisposing factors were xerostomia (n = 18), HIV (n = 5), immunosuppression in conjunction with organ transplantation (n = 10), and wearing of dentures (n = 14). For the remaining patients no specific predisposing factors were found. One patient who was treated with nystatin was excluded owing to nausea that was related to the antifungal treatment. After 7 days of treatment with fluconazole (50 mg/day), the affected oral mucosa, assessed by the investigator, was cured or showed considerable improvement in 87% of the patients (n = 30). The corresponding figure for the nystatin group (n = 30), rinsing with 1 mL 4 times a day for 21 days, was 80%. Following treatment with fluconazole, 20 of 22 patients with symptoms at the start (91%) reported improvement. The comparable figures for the nystatin group were 10 of 12 patients (83%). Half of the patients in the nystatin group reported inconvenience from taking the medication (mean value = 25.9) compared with 23% of the patients in the fluconazole group (mean value = 6.6). Eight patients in the fluconazole group and 12 patients in the nystatin group exhibited a relapse within 6 months. These differences were not found to be statistically significant. The patients in the fluconazole group reported less inconvenience from taking the medication, a finding that may have clinical implications for compliance.

Administration, Oral↗

PubMed1998

Distribution of interferon-gamma mRNA-positive cells in oral lichen planus lesions.

The present study investigated the potential involvement of interferon-gamma (IFN-gamma)-producing cells in the pathogenesis of oral lichen planus (OLP). On biopsies from 10 OLP patients, an in situ hybridization technique was employed to determine the topographical distribution of cells expressing IFN-gamma mRNA. It was estimated that approximately 1% or fewer lesional cells were IFN-gamma mRNA-positive. These cells were mainly encountered lining the basal membrane in a majority of the patients, or were in a few cases circumscribing the infiltrate, but were more seldom localized to the center of the lesion. A slightly higher, but not statistically significant, number of phytohemagglutinin (PHA)-induced IFN-gamma-producing cells, in vitro, was found in blood from 11 other OLP patients compared with blood from matched controls. Equal concentrations of IFN-gamma in supernatants from PHA-stimulated blood cells were detected in the two groups. Similarly, the IFN-gamma response towards C. albicans was alike in OLP and in healthy control (HC) blood cells, indicating normal immunological memory function in the OLP patients. A small set of cells with spontaneous IFN-gamma production was found in OLP and in HC peripheral blood. The data suggest that T-lymphocyte activation and cytokine production act locally and are not reflected in peripheral blood. The localization of the IFN-gamma mRNA-positive cells indicates that the antigenic peptides are presented at the periphery of the mononuclear cell infiltrate. Furthermore, the low frequency of IFN-gamma mRNA-positive cells in the lesions suggests that the disease is maintained by a small number of antigen-specific T cells.

Adult↗

PubMed1998

The frequency of different T-cell receptor V-families in oral lichen planus and lichenoid contact lesions: an immunohistochemical study.

Oral lichen planus (OLP) and lichenoid contact lesions (CL) are recognized as different pathological conditions of the oral mucosa. Cutaneous delayed-type hypersensitivity to mercury displayed by patients with CL but not by OLP patients supports the concept of different etiological mechanisms behind the two lesions. It is not possible to reveal this difference by histopathological assessments, and differences in clinical appearances are at present the only way to discriminate between the two conditions. It has recently been observed that T cells in OLP lesions express T-cell receptors (TCR) belonging to the Vbeta3 family in a higher frequency than expected from a random distribution, suggesting an involvement of superantigens as an etiologic factor behind this condition. In an effort to discriminate more clearly between OLP and CL, and to provide clues to the etiological mechanisms behind the two lesions, the TCR V-family distributions in the inflammatory infiltrates of OLP and CL were compared. Biopsies were taken from 10 patients with manifest OLP and 10 patients with CL. Frozen sections were incubated with antibodies against TCR Vbeta3, Valpha2 and Vbeta5a utilizing a standard immunoperoxidase technique. The frequency of Vbeta3.1 (clone 8F10) was calculated as 7%, and for Valpha2 less than 3%, and the results did not reveal any differences between OLP and CL regarding the frequencies of T-cell V-families. Thus, it was not possible to discriminate between OLP and CL by immunohistochemistry staining for different V families.

Adult↗

PubMed1998

Immune defense mechanisms of the dental pulp.

Defense reactions of the dentin/pulp complex involve a variety of biological systems, in which the immune system plays a pivotal role. The knowledge of the organization and function of pulpal immunocompetent cells has been sparse, but in recent years a significant body of information of immune mechanisms in general has provided a footing for substantial new knowledge of the immune mechanisms of the dental pulp. The identification of pulpal dendritic cells (DCs) has generated research activities which have led to a concept of how an antigenic challenge may evoke a pulpal inflammatory response. Although DCs are not able to identify foreign antigens specifically, they provide necessary signals to activate T-lymphocytes which in turn will orchestrate other immunocompetent cells to mount the local immune defense of the dental pulp. The purpose of this review is to accent the organization and function of pulpal DCs and other tissue and cellular components and to provide a basis for how they may interact to instigate pulpal defense mechanisms.

Antigen-Presenting Cells↗

PubMed1997

Perivascular dendritic cells of the human dental pulp.

The morphological and phenotypical features of the class II molecule (HLA-DR) expressing cells in human dental pulps were compared with those of previously characterized perivascular dendritic cells in the dermis. We have further investigated how these pulpal cells are structurally related to the vascular system. Double-immunofluorescence staining revealed that a substantial portion of the pulpal HLA-DR expressing cells also expressed factor XIIIa, a marker for dendritic cells. The cells usually had a highly dendritic appearance and formed a reticular network in the pulpal connective tissue. The majority of cells also expressed macrophage-related antigens (CD14 and CD68). A small but distinct population of pulpal cells, representing approximately 13% of the class II molecule expressing cells, was devoid of a typical macrophage phenotype. This subpopulation of pulpal cells may be similar to dendritic cells present in the dermis. Confocal laser scanning microscopy showed that highly dendritic cells, found in close relation to the endothelium, had dendritic processes which were found to be in contact with the peripheral cell membrane of the endothelial cells. These cells formed a three-dimensional structure around the microvessel resembling a cellular conduit. We conclude that the human dental pulp is equipped with class II molecule-expressing perivascular dendritic cells composed of a heterogeneous cell population.

Antigens, CD↗

PubMed1997

Immunotoxic effects of smokeless tobacco on the accessory cell function of rat oral epithelium.

Smokeless tobacco (ST) is known to adversely effect the oral mucosa, but knowledge about the influence on immune defence is limited. Few studies have investigated the effect of ST on the local immune response. In the present study, we have assessed the effect of a crude Swedish moist snuff (SS) extract, alkaloids, and nitrosamines on T-cell mitogenic response to Con A using epithelial cells, including Langerhans cells, of the rat oral mucosa as accessory cells. SS extract at a concentration of 4% reduced the T-cell proliferation by 50% (IC50 = 4%). Pretreatment of either oral epithelial cells or T-cells with SS extract also gave a significant inhibition of T-cell proliferation. This effect was not obtained following preincubation with SS components as alkaloids and different tobacco-specific nitrosamines (TSNA). None of the tested compounds were found to possess any mitogenic properties. This in vitro study showed that SS extract can evoke an immunosuppressive effect on mitogen-driven T-cell proliferation using cells from oral epithelium as accessory cells. This effect was more pronounced when SS extract was employed compared to when the single SS components were used alone.

Alkaloids↗

PubMed1997

Structural and functional association between substance P- and calcitonin gene-related peptide-immunoreactive nerves and accessory cells in the rat dental pulp.

Defense mechanisms of the dentin/pulp complex involve a variety of biological systems in which immunocompetent cells, the nervous system, and the vascular supply play important roles. In the present study, pulpal accessory cells were examined regarding (i) their structural relationship to nerves and (ii) how the functional capacities of these cells were affected by neuropeptides. Micro-anatomic association was investigated in the normal rat molar pulp with the use of double-immunofluorescence staining and dual-channel confocal laser scanning microscopy. Examinations of confocal laser scanning microscopic images from single focal planes revealed the presence of apparent contacts between thin, varicose nerve fibers and immunocompetent cells, indicating proximity between these two structures. The close associations were most frequently observed in the para-odontoblastic region of the coronal pulp, where more than 70% of class II antigen-expressing (OX6+) cells showed proximity to nerve fibers immunoreactive to calcitonin gene-related peptide. The corresponding figure for substance P was about 50%. ED2+ macrophages closely associated with nerves were less frequently observed. Functional studies conducted in vitro demonstrated that 10(-9) to 10(-7) mol/L of substance P significantly increased (p < 0.05), while 10(-7) to 10(-6) mol/L of calcitonin gene-related peptide suppressed (p < 0.01) proliferation of purified T-lymphocytes stimulated with sub-optimal concentrations of concanavalin A in the presence of rat incisor pulpal cells as accessory cells. These data suggest that pulpal sensory nerve fibers and their products may have an influence upon the immune defense of the dental pulp.

Animals↗

PubMed1996

Digital image analysis (DIA) of colour changes in human skin exposed to standardized thermal injury and comparison with laser Doppler measurements.

Clinical macrophotography followed by digitization and computer-assisted image analysis was performed on volunteers exposed to a mild experimental thermal injury. The aim was to elaborate a non-invasive technique allowing repetitive and quantitative monitoring of induced erythema and to evaluate a possible relationship with laser Doppler measurement of skin perfusion. A standardized 1 x 1 cm large thermal trauma was induced in the skin of the ventral forearm of 12 volunteers. Photographic recordings and skin blood flow measurements were made preburn and at 30-min, 1-h, 2-h, 4-h and 12-h postburn. Image analysis was performed with two colour systems, normalized rgb-values (rgb) and Hue-Saturation-Intensity (HSI). Erythema measured by rgb and HSI was most pronounced during the first hour postburn, after which it gradually decreased in order to increase again at 12 h postburn. Skin perfusion peaked at 30 min postburn and then continuously decreased during the course of the experiments. Degree of erythema could be quantified using both colour systems and a linear relationship was obtained between the observed colour changes of both systems and changes in skin perfusion. Results may also indicate that erythema can be present without a concomitant increase in skin perfusion, probably representing postburn venous stasis. The present study showed that digital image analysis is a non-invasive technique allowing repetitive and quantitative analysis of skin erythema which can be used to monitor pathophysiological changes in the body as well as the result of their treatment.

Adult↗

PubMed1996

Adverse reactions in the oral mucosa associated with anterior composite restorations.

This is a descriptive study of patients with symptomatic lichenoid-like reactions of the lips in contact with composite restorations (n = 12). Clinically, the lesions appeared as symptomatic single or multiple erythematous areas that included white papules. Candida was found by cultivation or histopathological examination in 7 of the lesions. Patch testing (n = 7) did not reveal any reactions to composite components, except for one patient who showed a delayed hypersensitivity reaction to formaldehyde. Replacement of existing dental materials parallel to antifungal treatment resulted in healing or significant improvement in 7 of 9 patients. This study shows that resin components can be associated with adverse reactions in the oral mucosa of the lips and that these reactions may be accompanied by an infection with Candida.

Adult↗

PubMed1995

Use of computer-assisted image analysis for noninvasive evaluation of oral lichenoid reactions and oral leukoplakia.

The objective of the present study was to elaborate and to evaluate a method in which the clinical appearance of a mucosal lesion could be expressed by means of color and morphologic features extracted from digitized images. The ability to express mucosal changes with image features was evaluated, as was the accuracy of a classification of the lesions on the basis of image feature analysis. Computer-assisted image analysis was performed on digitized color slides from 76 patients with lichenoid reactions that included both oral lichen planus and contact lesions and 20 patients with homogenous oral leukoplakia. Color features were measured according to the intensity-hue-saturation color system, and morphologic features were estimated by tracing the hyperkeratotic area. Hyperkeratinizing and inflammatory tissue reactions could be demonstrated and defined by image analysis. Image features indicating inflammatory tissue reactions were more pronounced in cases of oral lichenoid reactions. Morphologic parameters could express the anatomic appearance of the lesions. The comparison between histopathologic diagnosis and a classification through computerized analysis demonstrated that 90.5% of oral lichenoid reactions could be separated from homogenous oral leukoplakia by linear discriminant analysis.

Analog-Digital Conversion↗

PubMed1995

Effect of sonicated material from Fusobacterium nucleatum on the functional capacity of accessory cells derived from dental pulp.

Fusobacterium nucleatum-derived components were studied for their effect on the ability of accessory pulpal cells to induce T-lymphocyte proliferation. In initial experiments, spleen cells were used to establish concentration ranges at which testing of the effect of the bacterial components would be suitable. At low concentrations, bacterial substances induced a stimulatory effect on the proliferation rate of spleen cells, but not when purified T-lymphocytes were incubated in the presence of concanavalin A and pulpal accessory cells. At increasing concentrations, a dose-dependent reduction was observed. Pretreatment with the bacterial products for 4 h gave a stimulatory effect in the absence of concanavalin A for both spleen cells and T-lymphocytes. Removal of low-molecular weight components (<3.5 kDa) did not influence the inhibitory effect, whereas preheating the bacterial substances to 100 degrees C eliminated the observed inhibition. Findings show that heat-sensitive, high-molecular-weight components of F. nucleatum can evoke a concentration-dependent stimulatory or suppressive effect on the proliferation rate of T-lymphocytes in the presence of accessory cells derived from the dental pulp.

Analysis of Variance↗

PubMed1995

Antigen presenting capacity of Langerhans cells from rat oral epithelium.

The ability of Langerhans cells (LC) from rat oral mucosa to internalize and process antigens and to participate in the induction of T cell mitogenesis was examined. To purify LC from epithelial cells, monoclonal anti-class II antibodies and immunomagnetic beads were employed. Suspensions of epithelial cells, containing LC, were found to be effective in mediating a Con A-induced T cell proliferation. Depletion of class II molecule-expressing LC reduced the proliferation of T cells by 80%. Presentation of ovalbumin (OA) to primed T cells was found to be dependent on the concentration of OA and the number of LC. Partially purified LC were five times as effective in inducing proliferation of primed T cells as the untreated suspension of epithelial cells. The data suggest that LC obtained from rat oral mucosa can generate accessory signals, process antigens and serve as antigen-presenting cells.

Animals↗

PubMed1995

Effects of unpolymerized resin components on the function of accessory cells derived from the rat incisor pulp.

Monomeric resin components from dental composites are toxic to fibroblasts in culture and thus may interfere with the local immune system of the pulp, reducing its effective defense potential, either by cytotoxicity or by a more specific immune mechanism. Therefore, the present study was undertaken to observe the cytotoxic effects elicited by certain unpolymerized components of resin composites upon the function of accessory pulp cells in mitogen-induced proliferation of T-lymphocytes. Accessory cells from the rat incisor pulp were released following enzymatic digestion with collagenase. The assay included incubation of these cells with purified T-lymphocytes from cervical lymph nodes for 72 h in the presence of different concentrations of the resin components. The proliferative T-lymphocyte response was monitored by 3H-thymidine incorporation. Initially, we conducted experiments on spleen cells to determine the proper concentration intervals for suitable testing of the resin components. To assess the individual susceptibility of accessory cells and T-lymphocytes, we pre-treated each of these cells with some of the test materials prior to assay. At low concentrations, urethane dimethacrylate (UDMA), bisglycidyl methacrylate (bis-GMA), triethylene glycol dimethacrylate (TEGDMA), and bis-phenol A (BPA) increased spleen cell proliferation to concanavalin A (con A). Purified T-lymphocytes stimulated by pulpal cells did not show enhanced responses to UDMA, bis-GMA, glycidyl mehtacrylate (GMA), or N,N,-dihydroxyethyl-p-toluidine (DHEpT). At higher concentrations, all substances except camphoroquinone (CAMP) showed inhibitory effects in both test systems. The in vitro study shows that resin components can evoke either immunosuppression or immunostimulation on mitogen-driven proliferation of purified T-lyumphocytes and spleen cells.

Animals↗

PubMed1994

Determination of plasma proteins in dentinal fluid from cavities prepared in healthy young human teeth.

The discharge of albumin, IgG and fibrinogen in dentinal fluid released from freshly exposed dentine was determined by enzyme-linked immunosorbent assay. Data were compared with the relative concentrations of these proteins in the interstitial fluid of the pulp. The sampling procedure involved retrieval of phosphate-buffered saline placed in cavities exposing the dentine or pulp of young human premolars for a period of 15 min. Albumin and IgG were found in all dentine samples. The relative occurrence of these two proteins was similar in fluid samples from the exposed pulp. While fibrinogen was detected in all pulp samples only four of a total of 16 dentine samples displayed this protein. Shortly after a mechanical exposure, the exposed ends of the dentinal tubules will therefore release plasma proteins, although to a varying extent. The amount and quality appear related to the amount in which they are present in the interstitial fluid of the pulp.

Acid Etching, Dental↗

PubMed1994

T cell receptor V-gene usage in oral lichen planus; increased frequency of T cell receptors expressing V alpha 2 and V beta 3.

In order to analyse the clonality of T cells in the inflammatory infiltrate of oral lichen planus (OLP), mucosal biopsies were obtained from seven patients with manifest disease. The biopsies were stained with MoAbs directed against 11 different T cell receptor (TCR) V-gene families, anti-CD4, anti-CD8 and IL-2 receptor (IL-2R). For comparison, the frequencies of the different TCR V-families were determined in biopsies from five patients with oral candidosis as well as in peripheral blood from three patients with OLP and from six healthy blood donors (HBD). The occurrence of the investigated TCR V-families varied between 0% and 7% in venous blood obtained from both HBD and OLP patients. T lymphocytes expressing the TCR V beta 3 and V alpha 2 in OLP biopsies were, however, detected in frequencies ranging between 18% and 40% of the total fraction of lymphocytes, a consistent finding for all the OLP infiltrates studied. The other nine TCR V-families examined appeared in low frequencies both in biopsies and in peripheral blood. V alpha 2+ and V beta 3+ cells were often localized adjacent to the basal membrane. In contrast, T cells in Candida-induced lesions did not express a biased TCR distribution, and most V-families studied appeared in frequencies of 0-6%. Thus, T lymphocytes in OLP lesions express a substantially higher frequency of TCR V alpha 2 and V beta 3 than expected from the distribution in blood. The clonal expansion of T cells observed in OLP suggests that a superantigen is involved in the pathogenesis of the disease. Whether this superantigen is of exogenous or endogenous origin needs to be investigated.

Adult↗

PubMed1994

Difference in capacity between macrophages and dendritic cells from rat incisor pulp to provide accessory signals to concanavalin-A-stimulated T-lymphocytes.

The present study compared the ability of dendritic cells and macrophages derived from the dental pulp to provide accessory signals to Concanavalin A (Con A)-stimulated T-lymphocytes. Pulpal cells from maxillary and mandibular rat incisors were enzymatically released with collagenase. T-lymphocytes were isolated from rat cervical lymph nodes. In initial experiments, suspensions of unseparated pulpal cells were found to provide co-stimulatory help to Con-A-treated T-lymphocytes. The proliferation rate correlated well with the number of cells in the pulp suspension and followed a time course characteristic of a Con-A-driven proliferation of T-lymphocytes. Depletion of class II molecule-expressing cells from the unpurified suspension of pulpal cells resulted in lost ability to provide accessory signals to Con-A-stimulated T-lymphocytes. In contrast, removal of ED2-positive cells, i.e., macrophages, did not affect the ability of the suspension to give this assistance. Partially purified class II molecule-expressing cells enhanced the proliferative response, while addition of enriched macrophages did not. It was concluded that cells in the normal dental pulp with the characteristics of dendritic cells have the capacity to provide help to Con-A-stimulated T-lymphocytes, while cells with the macrophage phenotype lack this ability.

Animals↗

PubMed1994

Computer analysis in oral lichenoid reactions.

To improve diagnostic procedures and facilitate clinical decision-making, computer-assisted image analysis was performed on color slides from 30 patients with histopathologically verified oral lichenoid reactions. Areas from white hyperkeratotic and adjacent red inflamed areas of the lesions were selected and subjected to image analysis. The digitization of the color slides was done by means of an image scanner, and the digital information was transmitted to a personal computer for subsequent feature extraction and analysis. The different oral lesions were characterized as the difference in mean values between white hyperkeratotic and red inflamed areas, respectively, compared with clinically normal tissue. Statistical analyses were made on three different color systems: Red-Green-Blue (RGB), normalized red-green-blue (rgb), and Intensity-Hue-Saturation (IHS). The results showed statistically significant differences in all color systems for both the hyperkeratotic areas and adjacent inflammatory reactions. A linear correlation was obtained when the results of the image analysis of color variations were compared with a clinical score system for hyperkeratosis and inflammation evaluated by two investigators independently.

Algorithms↗

PubMed1993

Inhibition of serum albumin flux across exposed dentine following conditioning with GLUMA primer, glutaraldehyde or potassium oxalates.

A variety of medicaments used on dentine in various treatment procedures may cause a reduction in dentine permeability. By observing the flow of endogenous serum albumin across exposed dentine, agents known to promote dentine bonding of restorative resins or retard dentine sensitivity were assessed regarding their capacity to arrest dentinal fluid flow. Experiments were conducted in young adult macaque monkeys employing Class V cavity preparations in incisors and canines. A diffusion-in-gel-enzyme-linked-immunosorbent-assay (DIG-ELISA) was used to quantitate serum albumin in effluents from these cavities at various time periods following either no treatment or topical application with GLUMA primer, glutaraldehyde or potassium oxalates. While in untreated cavities serum albumin continued to flow even after a period of 1 week, a substantial reduction or complete cessation of serum albumin flux was seen following topical application of the agents tested, suggesting a durable effect on dentinal fluid flow. No difference between agents was observed. Further cutting of the cavity bottom a few tenths of a millimetre resulted in renewed flow of serum albumin. Data suggest that the solutions tested are capable of reducing dentinal fluid flow onto exposed dentine surfaces.

Acid Etching, Dental↗