Quantification Of Mast Cells Research Articles

Immunohistochemical quantification of mast cells in inflamed and noninflamed pulp tissue.

Background:Dental pulp inflammation is a very complex process due to its situation in low compliance (confined environment) surrounded by mineralized dentin. Mast cells are one of the mediators of inflammation. Immunohistochemical localization of mast cells by anti-tryptase antibodies in formalin-fixed paraffin-embedded sections has been shown to be highly specific. The aim of the present study is to quantify the mast cells in inflamed and noninflamed human pulp tissue using immunohistochemical analysis.Materials and Methods:Immunohistochemical localization of mast cells by anti-tryptase antibody was done in 15 inflamed and 15 noninflamed formalin-fixed paraffin-embedded pulp tissue. A number of mast cell per five high-power fields were performed using three observers and the mean was calculated. Statistical analysis was performed using t-test.Results:The results of the present study showed an increased number of mast cells in inflamed pulp in comparison with noninflamed pulp.Conclusion:Thus, the presence of mast cells in pulp inflammation could be used as a diagnostic marker. It can also aid in the management of pulpitis as mast cell stabilizers and antihistaminic agents could be used to control pulpal pain and inflammation.

Detection of Infiltrating Mast Cells Using a Modified Toluidine Blue Staining.

Mast cells are part of the immune system and characteristically contain histamine- and heparin-rich basophilic granules. While these cells are usually associated with allergy and anaphylaxis, they also promote wound healing and angiogenesis and confer protection against pathogens. The presence of these cells is sometimes indicative of a poor prognosis, especially in skin cancer, pancreatic cancer, and lymphoma. Toluidine blue staining of acid-fast granules is an established method for the identification and quantification of mast cells. Generating detailed information on the location of mast cells within tissues is problematic using this technique and often requires serial sections from adjacent tissue to be separately stained with hematoxylin and eosin (H&E). Staining serial sections is not always possible, particularly if the sample is very small or rare. In such cases, a method of simultaneously identifying and localizing mast cells in a tissue would be advantageous. Toluidine blue and H&E are not commonly combined because H&E includes repetitive washes in water, which may affect the efficacy of the aqueous-soluble toluidine blue. We have developed and tested a novel staining technique that integrates toluidine blue between hematoxylin and eosin in one simple procedure. This protocol works on both frozen and formalin-fixed, paraffin-embedded tissue and readily allows for the identification of purple-stained mast cells against a clean H&E background. This facilitates a more accurate localization and proper counting of mast cells in normal and affected tissue.

Quantification of mast cells in different stages of periodontal disease.

Mast cells are mononuclear cells originating from bone marrow. They produce various biologically active substances, which allow them to actively participate in immune and inflammatory processes associated with periodontal disease. The study focused on distribution and density of mast cells in healthy gingiva as well as in different stages of periodontal disease. The material used for this purpose was gingival biopsies taken from 96 patients classified into 4 groups: healthy gingiva, gingivitis, initial and severe periodontal disease. Toluidine blue staining according to Spicer was utilized for identifying mast cells. Basing on our study, the density of mast cells in the gingival tissue increases with the progression of the infection, which means they are more numerous in gingivitis compared to healthy gingiva, as well as in periodontal disease compared to gingivitis. Increase in the number of mast cells in the infected gingiva can be correlated with an increased influx of inflammatory cells from blood circulation into the gingival stroma, as well as with the collagen lysis, since these cells produce substances with collagenolytic potential. Based on the distribution of mast cells, it could be concluded that in the evolution of periodontal disease there are significant dynamic alterations in migration and localization of these cells.

Quantification and localization of mast cells in periapical lesions.

Background:Periapical lesions occur in response to chronic irritation in periapical tissue, generally resulting from an infected root canal. Specific etiological agents of induction, participating cell population and growth factors associated with maintenance and resolution of periapical lesions are incompletely understood. Among the cells found in periapical lesions, mast cells have been implicated in the inflammatory mechanism.Aim:Quantifications and the possible role played by mast cells in the periapical granuloma and radicular cyst. Hence, this study is to emphasize the presence (localization) and quantification of mast cells in periapical granuloma and radicular cyst.Materials and Methods:A total of 30 cases and out of which 15 of periapical granuloma and 15 radicular cyst, each along with the case details from the previously diagnosed cases in the department of oral pathology were selected for the study. The gender distribution showed male 8 (53.3%) and females 7 (46.7%) in periapical granuloma cases and male 10 (66.7%) and females 5 (33.3%) in radicular cyst cases. The statistical analysis used was unpaired t-test.Results:Mean mast cell count in periapical granuloma subepithelial and deeper connective tissue, was 12.40 (0.99%) and 7.13 (0.83%), respectively. The mean mast cell counts in subepithelial and deeper connective tissue of radicular cyst were 17.64 (1.59%) and 12.06 (1.33%) respectively, which was statistically significant. No statistical significant difference was noted among males and females.Conclusion:Mast cells were more in number in radicular cyst. Based on the concept that mast cells play a critical role in the induction of inflammation, it is logical to use therapeutic agents to alter mast cell function and secretion, to thwart inflammation at its earliest phases. These findings may suggest the possible role of mast cells in the pathogenesis of periapical lesions.

Effect of laser therapy on the inflammatory response induced by endodontic medications implanted into the subcutaneous tissue of rats

INTRODUCTION: Endodontic medications contain toxic components that cause varying degrees of inflammation.OBJECTIVE: This study evaluated the effect of laser therapy on the inflammatory response induced by intracanal medications implanted into the subcutaneous tissue of rats using a quantitative analysis of mast cells.MATERIAL AND METHOD: Polyethylene tubes containing the medications were implanted in the dorsum of 60 rats divided into six groups, including HS (P.A. calcium hydroxide paste), HL (P.A. calcium hydroxide paste and laser therapy), HPS (P.A. calcium hydroxide paste with camphorated paramonochlorophenol), HPL (P.A. calcium hydroxide paste with camphorated paramonochlorophenol and laser therapy), IS (iodoform with saline) and IL (iodoform with saline and laser therapy). The animals were euthanized eight or fifteen days after surgery, and samples were removed and embedded in paraffin. Histological sections were stained with 0.2% toluidine blue for the quantification of mast cells. Analysis of variance (ANOVA) and Tukey's post-hoc test were applied to determine significant differences in the number of mast cells between groups (p<0.05).RESULT: There was a decrease in mast cells for the HL, HPL and IL groups when compared with the HS, HPS and IS groups at both time points. There was no statistically significant difference between the HPS and HPL groups at the eight-day time point.CONCLUSION: Laser therapy was effective at modulating the inflammatory response induced by endodontic medications by significantly reducing the number of mast cells.

Evaluation of in situ expression of effector and regulatory cytokines, TLR, galectins and matrix metalloproteinases in oral manifestations of paracoccidioidomycosis

BackgroundAlthough the pathophysiology of paracoccidioidomycosis (PCM) is not completely understood, the study of immune response against fungus has provided insight into understanding the natural course of the disease and its clinical manifestations, hence contributing to the development of preventive measures and treatment proposals. The aim of this study was to evaluate the histopathological and immunological aspects involved in the role of different effector and regulatory responses, as well as the correlation between the TLRs, Galectins, Matrix Metalloproteinases and cytoplasmic proteases of mast cells in this infection. MethodsSixteen biopsy specimens with oral lesions of chronic PCM, as well as 13 sections of normal oral mucosa were analyzed. Histopathological and immunological aspects involved in the role of different effector and regulatory responses were evaluated. Indirect immunohistochemistry was performed for IL-17, IL-10, IL-4, TGF-β, FoxP3, Gal-1, Gal-3, Gal-9, TLR-2, TLR-4, MMP-3 and MMP-9, as well as for chymase and tryptase for mast cells identification. Fibrosis was quantified using Picrosirius. ResultsThere was a significant increase in the area of fibrosis and in the number of cells expressing IL-10, IL-4, IL-17, FoxP3, Gal-3, TLR-2, MMP3 and MMP9 in patients with PCM in comparison with patients in the group control. There was no difference in the expression of TGF-β, TLR-4, Gal-1 or Gal-9. Mast cells number was found to be significantly lower in oral chronic PCM when compared to control samples after quantification of mast cells and expression of chymase and tryptase. PCM granulomas were classified to the morphological aspects in organized ou non-organized. Expression of IL-4 in non-organized granulomas was significantly higher. ConclusionThe proteins studied herein appear to play an important role in the development and maintenance of oral lesions of PCM, as well as in the processes of development and progression of lesions caused by the fungus and by the immune response associated with the infection.

Esophageal mucosal mast cell infiltration and changes in segmental smooth muscle contraction in noncardiac chest pain.

Mast cells release potent mediators that alter enteric nerve and smooth muscle functions and may contribute to the pathogenesis of functional gastrointestinal disorders. The goal of this study was to determine if mucosal mast cell infiltration was associated with smooth muscle segmental changes in esophageal contraction. All patients with noncardiac chest pain (NCCP) were divided into two groups consisting of patients with non-erosive reflux disease or functional chest pain (FCP) according to the results of ambulatory 24 hours esophageal pH monitoring and high-resolution manometry. Pressure-volume (PV) was calculated by multiplying the length of the esophageal segment, duration of the contraction, and mean pressure over the entire space-time box (P mean). Quantification of mast cells was performed in five consecutive nonoverlapping immunostained sections. Spearman correlation analysis showed that the distal segment PV correlated with the mast cell count in all of the patients combined and in patients with FCP with correlation coefficients of 0.509 and 0.436, respectively (P = 0.004 and P = 0.042). Similar findings were observed for the segmental ratio of distal to proximal smooth muscle PV in all patients and in patients with FCP (correlation coefficients 0.566; P = 0.001 and correlation coefficients 0.525; P = 0.012, respectively). Mucosal mast cell infiltration was associated with distal esophageal contraction as a key pathophysiologic factor of NCCP.

A quantitative analysis of mast cells in inflammatory periapical and gingival lesions.

The aim of the study was to quantify the presence of mast cells in various inflammatory lesions like periapical granuloma, periapical cyst, inflammatory gingival hyperplasia and pyogenic granuloma. Mast cell degranulation and association with lymphocytes were also recorded in an attempt to understand the role of mast cells in the pathogenesis of these inflammatory lesions. The quantification of mast cells was done on toluidine blue stained sections of all the four groups of lesions, using the image analyzer software, Image-Pro-Express (Media Cybernetics, USA). An increased number of mast cells in various inflammatory lesions with a significant difference between the four groups were noted. Mast cell number tended to be greater in the lesions present in the anterior region of the mouth than in the posterior region of the oral cavity. The mean mast cell number decreased with the increasing age which was directly correlated with the age of the patients. Mast cell site, distribution, degranulation and its association with fibroblasts, lymphocytes and blood vessels were noted. The location of mast cells in different areas, their association with lymphocytes, fibroblasts, endothelial cells, and the phenomenon of degranulation helps to appreciate the release of various mediators and multiple interactions among these cells, leading to increased vascular permeability, angiogenic response, collagen synthesis, regulation of inflammation, bone resorption, and extracellular matrix destruction, thus contributing to the pathogenesis of these inflammatory lesions.

Lactose intolerance in irritable bowel syndrome patients with diarrhoea: the roles of anxiety, activation of the innate mucosal immune system and visceral sensitivity

Irritable bowel syndrome patients with diarrhoea (IBS-D) often report intolerance to milk; however, the mechanism underlying these symptoms is unknown. To assess the role of psychological factors, immune activation and visceral sensitivity on the development of lactose intolerance (LI) in IBS-D patients. Fifty-five IBS-D patients and 18 healthy controls (HCs) with lactase deficiency underwent a 20-g lactose hydrogen breath test (LHBT). Patients were categorised as lactose malabsorption (LM; malabsorption only) or LI [malabsorption plus increase in total symptom score (TSS). Measurements included (i) psychological status; (ii) enteric biopsies with quantification of mast cells (MCs), T-lymphocytes and enterochromaffin cells; (iii) serum cytokines; (iv) rectal sensitivity before and after lactose ingestion. LI was more prevalent in IBS-D patients than HCs [25/55 (46%) vs. 3/18 (17%), P = 0.029]. IBS-D patients with LI had (i) higher levels of anxiety than those with LM (P = 0.017) or HCs (P = 0.006); (ii) increased mucosal MCs compared with LM (P = 0.006) and HCs (P < 0.001); (iii) raised serum TNF-α compared with LM (P = 0.034) and HCs (P < 0.001) and (iv) increased rectal sensitivity after lactose ingestion compared with LM (P < 0.001) or HCs (P < 0.001). Severity of abdominal symptoms after lactose ingestion was associated with the increase in visceral sensitivity after lactose intake (r = 0.629, P < 0.001), MCs (r = 0.650, P < 0.001) and anxiety (r = 0.519, P < 0.001). IBS-D patients with lactose intolerence are characterised by anxiety, mucosal immune activation and increased visceral sensitivity after lactose ingestion. The presence of these biomarkers may indicate an IBS phenotype that responds to dietary therapy and/or mast cell stabilisers.

OC-035 Mechanism of Lactose Intolerance in Irritable Bowel Syndrome: Role of Anxiety, Mucosal Immunity and Visceral Hypersensitivity

Introduction Many patients, especially those with Irritable Bowel Syndrome (IBS), report food intolerance; however the mechanism underlying these “functional digestive symptoms” is unknown. We assessed the role of psychological factors, mucosal immune activation and visceral sensitivity on the development of lactose intolerance (LI) after ingestion of 20g lactose in IBS patients and healthy controls (HCs) with lactase deficiency: a validated, clinical experimental model of intolerance to poorly absorbed, fermentable foods (Yang et al Clin Gastro Hep 2013 in publication). Methods IBS-D patients meeting Rome III criteria (n = 277) and age/sex matched HCs (n = 64) underwent a 20g lactose hydrogen breath test (LHBT) with measurement of hydrogen production, abdominal distention, and LI symptoms. Hospital Anxiety and Depression Score assessed psychologic state. Barostat measured rectal sensitivity. Additionally, 55 IBS-D patients and 18 HCs completed colonoscopy with colon and terminal ileum (TI) biopsies for quantification of mast cells (MCs), T lymphocytes, and enterochromaffin cells (ECC). Results Hydrogen production and distention were similar in IBS patients and HCs during LHBT; however LI symptoms were more frequent in IBS (54% vs. 28%, P < 0.001), including bloating (39% vs . 14%, P < 0.001), borborygmi (39% vs. 22%, P = 0.010), pain (31% vs. 11%, P = 0.001) and diarrhoea (29% vs. 9%, P = 0.001). IBS patients were more anxious (p < 0.001) and had higher rectal sensitivity than HCs ( P = 0.001). Multivariate analysis indicated that hydrogen production increased the likelihood of bloating (OR2.2 (95%CI 1.1–4.4), P = 0.028) and borborygmi (OR12.4 (3.3–45.8), P < 0.001), but not objective distention ( P = 0.673). Visceral hypersensitivity also associated with bloating (OR6.6 (1.7–25.0), P = 0.005) and total symptom score (OR3.7 (1.3–10.9, P = 0.014). A planned subanalysis showed that, compared to IBS patients with no symptoms, those with LI were more anxious (p = 0.045) and more likely to have visceral hypersensitivity (p < 0.001). In those that had colonoscopy, IBS patients with LI (25/55 (45%)) had increased MCs (p < 0.006), T-cells and ECC (both p < 0.05) in proximal colonic and TI mucosa compared to patients without LI and HCs. Multivariate analysis indicated that total LI symptom score was associated with anxiety (r = 0.519, P < 0.001), MCs in terminal ileum (r = 0.650, P < 0.001) and visceral sensitivity (r = 0.629, P < 0.001). Conclusion Gas production and sensitivity to luminal distension both contribute to digestive symptoms after lactose ingestion in patients with lactase deficiency. IBS-D patients with LI are characterised by anxiety, evidence of mucosal immune activation and visceral hypersensitivity. Disclosure of Interest None Declared

Quantification of mast cells in the uterine cervix of women infected with human immunodeficiency virus

The objective of the study was to identify mastocytosis in the chorionic epithelium of the uterine cervix in HIV-infected and non-HIV-infected women in autopsy specimens using histochemistry and immunohistochemistry techniques. Sixteen cervical tissue specimens were collected, of which 10 (62.50%) were from HIV-infected women. Histochemical and immunohistochemical techniques were used to evaluate mast cell density using Giemsa stain and anti-mast cell tryptase and anti-mast cell chymase antibodies, respectively. The study of the sheets and counting of mast cells with blue (Giemsa) or brown staining (anti-mast cell tryptase or chymase antibodies) were performed by 3 examiners, and 10 consecutive fields were examined under a light microscope at 400× magnification. A significant difference was found in mast cell density in the chorionic epithelium of the cervix in HIV-infected compared with non-HIV-infected women. The present study may contribute to the characterization of genital mucosa abnormalities and help better understand the potential role of mast cells in HIV-infected women.

Quantification of Mast Cells and Blood Vessels in the Skin of Patients With Cutaneous Mucinosis

Recent studies have suggested that mast cell numbers are increased in the skin of patients with cutaneous mucinosis and that these cells may have an important role in angiogenesis and production of mucin. Then, skin biopsies from 30 patients with cutaneous mucinosis (papular mucinosis, focal mucinosis, and mucinosis associated with lupus erythematosus) and from 10 healthy subjects were analyzed. Mast cells and blood vessels were immunolabeled with anti-tryptase and anti-CD34 antibodies, respectively, and then quantified stereologically. Counting was performed in papillary and reticular dermis. An increase in the number of mast cells was observed in the skin of patients with cutaneous mucinosis compared with the control group. Only minimal differences were observed in vessel stereology. There was no correlation between the increase in the number of mast cells and the number of blood vessels in the patients studied. There was no significant difference in the numbers of mast cells or blood vessels between the 3 subgroups of cutaneous mucinosis. Although many clinical forms of mucinosis have been described, neither mast cell number nor vessel distribution seems to distinguish the 3 different forms studied here.

Presence and quantification of mast cells in the gingiva of cats with tooth resorption, periodontitis and chronic stomatitis

Objective Mast cells are tissue-dwelling granule-containing immune cells that play a pivotal role in the pathogenesis of inflammation and other processes. The three most common orodental disorders in cats are periodontitis, feline resorptive lesions (FRL), and chronic gingivostomatitis (FCGS). The presence and density of mast cells in the gingiva has been established in healthy cats but not in cats affected by FRL, FCGS or periodontitis. The aim of the present study was to document and quantify the presence of mast cells in the gingiva adjacent to teeth affected by FRL, FCGS or chronic periodontitis. Methods Samples from the gingiva of 32 cats affected by FRL, FCGS or periodontitis were obtained and compared to samples obtained from 7 specific pathogen-free (SPF) cats. Evaluation of mast cells and the inflammatory infiltrate were performed on hematoxylin and eosin, and toluidine blue stained sections. Results Mast cells densities were significantly increased in gingival tissues adjacent to teeth affected by FRL, FCGS or periodontitis in comparison to SPF samples. There were no significant differences between gingival tissues of the FRL, FCGS and periodontitis groups. However, the relative inflammatory score in the FRL group was significantly lower as compared to the FCGS or periodontitis groups, yet with similar density of mast cells. Conclusion In the gingiva of cats affected with FRL, FCGS or periodontitis, there is an increase in the number of mast cells. The high number of mast cells in the FRL group and concurrent mild inflammatory reaction suggests the notion that mast cells may potentially play role in the pathogenesis of FRL.

Mastocytosis

Mastocytosis, an unusual disorder of bone marrow-derived, clonally transformed hematopoietic progenitor cells, exhibits a broad spectrum of clinical and morphologic features ranging from a self-limiting benign disorder (ie, juvenile cutaneous mastocytosis) to highly aggressive neoplasms like mast cell leukemia. Principally, mastocytosis should be divided in 2 main subentities: cutaneous mastocytosis and systemic mastocytosis mainly involving the bone marrow. Mastocytosis is a morphologic diagnosis and should not be diagnosed on the basis of clinical findings alone. Pathologists need to be aware of the disease and its mimickers. Application of the defined diagnostic criteria can confirm or exclude mastocytosis in most cases. Use of antibodies against tryptase, CD117 (KIT), and CD25 is recommended in every suspected case. Because most cases of systemic mastocytosis show a very low degree of infiltration of the bone marrow, antitryptase and anti-CD117 are of major importance for screening and quantification of mast cells, in particular to detect even small compact infiltrates as the only major diagnostic criterion for mastocytosis. Expression of CD25 on mast cells is defined as a minor diagnostic criterion and is usually seen only in mastocytosis but not in reactive states of mast cell hyperplasia.

Neuroimmune Interaction and Anorectal Motility in Children With Food Allergy-Related Chronic Constipation

Food allergy is thought to trigger functional constipation in children but the underlying mechanisms are still unknown. Mast cells (MCs) and their relationship with nerve fibers (NFs) in the rectal mucosa, as well as anorectal motility, were studied in children with refractory chronic constipation before and after an elimination diet for cow's milk, egg, and soy proteins. Thirty-three children (range: 1-10.8 years) underwent anorectal manometry and suction rectal biopsy before and after 8 weeks of oligoantigenic diet. MCs and NFs were identified immunohistochemically. Quantification of MCs (%MC/area) and MCs within 10 microm of NFs (%MC-NF/area) was performed by computer-assisted analysis. Eighteen children responded to the diet (R-group) and fifteen did not (the NR-group). At baseline there was a significant difference in anal resting pressure (ARP; mm Hg), percentage of relaxation (%R), and residual pressure (RP; mm Hg) of anal canal during rectal distension between the R-group (66+/-4.1, 84.3+/-2.8, 10.4+/-2.3, respectively) and the NR-group (49+/-5, 92.2+/-1.7, 4.8+/-1.7, respectively; P<0.05). After the diet, significant changes in ARP, RP, and %R were observed only in the R-group (44+/-3.7, 93.7+/-1.5, 3.8+/-1.2, respectively; P<0.05). At baseline, the R-group showed an increase in %MC/area (8.3+/-0.7) and %MC-NF/area (5.2+/-2.6) with respect to the NR-group (5.1+/-0.5 and 2.3+/-0.4, respectively; P<0.05). After the diet, only the R-group showed a significant reduction of %MC/area and %MC-NF/area (4.4+/-0.5 and 2.2+/-0.4, respectively; P<0.001). Both ARP and RP significantly correlated with %MC/area and %MC-NF/area; %R showed a significant inverse correlation with both %MC/area and %MC-NF/area. In children with food allergy-related chronic constipation, an increase in both rectal MC density and spatial interactions between MCs and NFs correlates with anal motor abnormalities. These variables are significantly affected by the diet.

Pain, mast cells, and nerves in peritoneal, ovarian, and deep infiltrating endometriosis

To detect and quantify mast cells in peritoneal, ovarian, and deep infiltrating endometriosis and to study the relationship between mast cells and nerves in endometriosis. Prospective histological and immunohistochemical study. University of Brussels, Belgium. Sixty-nine women undergoing laparoscopic excision of endometriosis for pain. Thirty-seven biopsies of normal tissue were obtained from women without endometriosis. Excision of endometriosis from different anatomical locations. Immunohistochemistry with chymase and tryptase to confirm the presence of mast cells and activated mast cells, respectively, in endometriotic lesions. Quantification of mast cells, activated mast cells, and degranulating mast cells in the different locations of endometriosis. Study of the relationship between mast cells and nerves by quantifying mast cells located less than 25 mum from nerves immunohistochemically stained with S-100 protein. Preoperative pain score evaluation by visual analogue scales. Patients with deeply infiltrating lesions had significantly higher preoperative pain scores than patients with peritoneal or ovarian endometriosis. Mast cells and degranulating mast cells are significantly more abundant in endometriotic lesions than in nonaffected tissues. Deep infiltrating lesions show a significantly higher number of mast cells, activated mast cells, and mast cells located <25 microm from nerves than peritoneal and ovarian lesions. We found significantly more degranulating mast cells in deep infiltrating lesions than in peritoneal lesions. The presence of increased activated and degranulating mast cells in deeply infiltrating endometriosis, which are the most painful lesions, and the close histological relationship between mast cells and nerves strongly suggest that mast cells could contribute to the development of pain and hyperalgesia in endometriosis, possibly by a direct effect on nerve structures.

Mast Cell Quantification in Normal Peritoneum and During Peritoneal Dialysis Treatment

Mast cells (MCs) have been implicated in fibrogenesis, angiogenesis, and immunity against bacteria. These 3 mechanisms participate in the peritoneal pathology secondary to peritoneal dialysis (PD) treatment. Despite their potential relevance to PD-related pathology, few studies have focused on MCs. To evaluate possible variations in the number of MCs during PD treatment. A quantitative study of tissue MCs in normal and pathologic peritoneum. Parietal peritoneal biopsies were collected from 4 groups: (1) normal controls (n = 9), (2) uremic non-PD patients (n = 16), (3) uremic patients on PD (n = 26), and (4) non-renal patients with inguinal hernia (n = 20). MCs were evaluated using immunohistochemistry for the detection of tryptase. The total number of cross sections of vessels per peritoneal field was examined in 22 of the 26 peritoneal biopsies of PD patients. PD tissue samples showed fibrosis, mesothelial cell loss, and variable hyalinizing vasculopathy. The number of MCs was similar in normal controls and non-PD uremic patients (mean +/- SE: 7.13 +/- 0.67 and 7.74 +/- 0.74 MCs/mm2, respectively). Peritoneal dialysis patients showed a reduction (4 +/- 0.38 MCs/mm2, P < .001), whereas hernia sac samples showed an increase (10.59 +/- 3.48 MCs/mm2). MC reduction showed no correlation with time on dialysis, fibrosis, number of vessels, or previous episodes of peritonitis. The peritoneum of patients receiving PD treatment shows a reduction of MCs. Despite such a reduction, fibrosis takes place, suggesting that MCs do not play a critical role in fibrosis genesis. Mast cell loss may be a contributory factor to peritonitis episodes in PD patients.

Quantification of mast cells in different stages of human periodontal disease

Among the cells involved in immune and inflammatory responses in periodontal disease, mast cells have been shown to be capable of generating a large number of biologically active substances. The present study was undertaken to identify and quantify the presence of mast cells in different stages of human periodontal disease using histochemical (toluidine blue) and immunohistochemical (tryptase-positive mast cells) techniques. Mast cell densities (cells per mm(2)) were significantly increased in chronic periodontitis/gingivitis lesions compared with clinically healthy gingival tissues (Health) uniquely by immunohistochemical technique. Interestingly, mast cells were distributed specially in close apposition to mononuclear cells. In human periodontal disease there is an increase in the number of mast cells that may be participating either in the destructive events or in the defense mechanism of periodontal disease via secretion of cytokines, including perpetuation of the Th2 response, and cellular migration and healing processes.

Mast cell subsets and neuropeptides in leprosy reactions.

The immunohistochemical identification of neuropeptides (calcitonin gene-related peptide, vasoactive intestinal polypeptide, substance P, alpha-melanocyte stimulating hormone and gamma-melanocyte stimulating hormone) quantification of mast cells and their subsets (tryptase/chymase-immunoreactive mast cells = TCMC and tryptase-immunoreactive mast cells = TMC) were determined in biopsies of six patients with leprosy reactions (three patients with type I reaction and three with type II). Biopsies were compared with those taken from the same body site in the remission stage of the same patient. We found a relative increase of TMC in the inflammatory infiltrate of the reactional biopsies compared to the post-reactional biopsy. Also, the total number of mast cells and the TMC/TCMC ratio in the inflammatory infiltrate was significantly higher than in the intervening dermis of the biopsies of both periods. No significant difference was found regarding neuroptide expression in the reactional and post-reactional biopsies. The relative increase of TMC in the reactional infiltrates could implicate this mast cell subset in the reported increase of the immune response in leprosy reactions.

Quantification of mast cells and microflora in the vaginal cul-de-sac of the brushtail possum (Trichosurus vulpecula).

Mast cells are typically associated with biological responses to intracellular parasitic or bacterial invasion in gut and pulmonary tissues. Large numbers of these cells are present in the vaginal cul-de-sac, a component of the reproductive tract in female brushtail possums (Trichosurus vulpecula). The presence of mast cells in this area may reflect microbial presence or indicate a role for mast cells in reproductive function in this marsupial. In this study, the number and spatial location of mast cells in vaginal cul-de-sac tissues at different reproductive stages was determined, and related to the presence of microflora. Vaginal cul-de-sac tissue was collected from juvenile (n = 5), lactationally anoestrous and cyclic adult brushtail possums (n = 6 per group). Oestrous cyclicity was induced by removal of pouch young and reproductive status was confirmed by laparoscopy. Tissue was collected aseptically for microbiological procedures. The fractionator and optical disector stereological methods were used to quantify mast cell populations. In all groups, microflora populations were low (< 5 x 10(5) organisms g(-1)). Mast cell density in epithelial tissue was highest in lactationally anoestrous and luteal phase brushtail possums and lowest in follicular phase animals. No correlation between the numbers of bacteria isolated and mast cell density was apparent. Gram stained tissue showed no evidence of bacterial invasion. Mast cell density was significantly lower in epithelial tissue from follicular phase animals, corroborating previous studies in which an increase in mast cell degranulation coincided with high oestrogen concentrations.