The presence of Mott cells in the lymph nodes of rats with experimental autoimmune encephalomyelitis.

Mott cells are plasma cells that have multiple spherical Russell bodies packed in their cytoplasm. Russell bodies are dilated endoplasmic reticulum cisternae filled with aggregates of immunoglobulins that are neither secreted nor degraded. Mott cells were observed in our study by light and electron microscope in the lymph nodes of rats with experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Mott cells were detected on hematoxylin and eosin (HE)-stained lymph node sections as vacuolated cells with eccentrically positioned nuclei and large number of faint blue spherical inclusions in the cytoplasm. Electron microscopic investigation revealed the presence of Russell bodies of the "medusa" form inside Mott cells in lymph node ultra-thin sections of EAE animals. Mott cells expressed the plasma cell marker CD138 and either kappa or lambda immunoglobulin light chains, indicating their origin from polyclonally activated B cells. Finally, Mott cells were associated with active EAE, as they were not found in the lymph nodes of EAE-resistant Albino Oxford rats. The presence of Russell bodies implies an excessive production of immunoglobulins in EAE, thus further emphasizing the role of B cells, and among them Mott cells, in the pathogenesis of this animal model of multiple sclerosis.

Similar developmental patterns of ghrelin- and glucagon-expressing cells in the human pancreas.

The pancreas appears to be a major source of ghrelin during fetal development, but the ontogeny of ghrelin cells in the human pancreas and their developmental relationship with α- and ß-cells remain largely unknown. In the present study, we examined the dynamics of ghrelin cell growth, colocalization of ghrelin with major pancreatic hormones and defined the similarities and differences among developmental patterns of ghrelin-, glucagon- and insulin-expressing cells in the human pancreas. To this end, paraffin-embedded pancreatic tissue sections from human embryos and fetuses were assessed by immunohistochemistry. Ghrelin-positive cells were first detected in the pancreas of 11-week-old fetuses. With advancing gestational age, both ghrelin- and glucagon-expressing cells were increasingly observed at the periphery of the developing islets, whereas insulin-containing cells were typically found in the islet core. Double immunohistochemistry showed that ghrelin-expressing cells were clearly separate from insulin-, somatostatin- and pancreatic polypeptide-containing cells. In contrast, cells coexpressing ghrelin and glucagon were sporadically detected during both the early and late fetal periods. Furthermore, morphometric analysis revealed a similar trend in the volume density of ghrelin- and glucagon-positive cells, and a contrasting pattern in ß-cell density at specific time points during the development of the human pancreas. This study demonstrates that the developmental pattern of ghrelin cells, although clearly distinct, is quite similar to that of glucagon-expressing cells. The obtained findings indicate a close lineage relationship between these cell populations, a functional relationship between their secretory products and an auto/paracrine mode of ghrelin-glucagon interaction in pancreatic development.

Blockade of nitric oxide synthesis modulates rat immunoglobulin A.

OBJECTIVE: Nitric oxide (NO) is known as a regulator of inflammation and immunity. The purpose of this study was to investigate the influence of this signal molecule on the rat immunoglobulin A (IgA) system using Nomega-nitro-L-arginine-methyl ester (L-NAME), which inhibits the activity of all isoforms of NO synthase. METHODS: The experiments were performed on adult female Wistar rats showing diestrus day 1 that were treated with L-NAME (30 or 50 mg/kg, s.c.). Untreated and saline-injected animals were used as controls. The rats were sacrificed 3 h following L-NAME or saline administration. The concentration of IgA in serum and intestinal extracts was determined by a sandwich enzyme-linked immunosorbent assay. The number of IgA-expressing cells per area unit of Peyer's patches and the intestinal lamina propria was evaluated using stereological analysis. RESULTS: The results showed that L-NAME decreased the level of IgA in serum and elevated its concentration in intestinal extracts. Additionally, the increased number of IgA+ cells was found in the intestinal lamina propria in both experimental groups. CONCLUSION: Obtained findings imply that endogenous NO may modulate the IgA system in the rat.

G cells and gastrin in chronic alcohol-treated rats.

Numerous reports have described gastric mucosal injury in rats treated with high ethanol concentrations. However, to the best of our knowledge, ultrastructural characteristics of G cells and antral gastrin levels have not been previously reported, either in rats that chronically consumed alcohol or in human alcoholics. The goal of this study was to examine the effect of ethanol consumption (8.5 g/kg) over a 4-month period, under controlled nutritional conditions, on antral and plasma levels of gastrin, ultrastructure of G cells, morphometric characteristics of G cells by stereological methods, and analysis of endocrine cells in the gastric mucosa by immunohistochemistry. The chronic alcohol consumption resulted in a nonsignificant decrease in gastrin plasma levels and unchanged antral gastrin concentrations. A slightly damaged glandular portion of the gastric mucosa and dilatation of small blood vessels detected by histological analysis, suggests that ethanol has a toxic effect on the mucosal surface. Chronic alcohol treatment significantly decreased the number of antral G cells per unit area, and increased their cellular, nuclear, and cytoplasmatic profile areas. In addition, the volume density and diameter of G-cell granules, predominantly the pale and lucent types, were increased, indicating inhibition of gastrin release. Ethanol treatment also decreased the number of gastric somatostatin-, serotonin-, and histamine-immunoreactive cells, except the somatostatin cells in the pyloric mucosa, as well as both G: D: enterochromaffin cells (EC) cell ratios in the antrum and D: ECL cell ratios in the fundus. These results indicate that the change of morphometric parameters in G cells may be related to cellular dysfunction. Our findings also suggest that regulation of G-cell secretion was not mediated by locally produced somatostatin in ethanol-consuming rats, but may involve gastric luminal content and/or neurotransmitters of gastric nerve fibers.

Possible mechanism of acute effect of ethanol on intestinal IgA expression in rat.

The purpose of this study was to investigate the possible mechanism of acute effect of ethanol on IgA expression in rat intestine. To this end, adult female Wistar rats showing diestrus day 1 were treated with (a) ethanol (2 or 4 g/kg, i.p.); (b) N omega-nitro-L-arginine-methyl ester (L-NAME), which inhibits the activity of all isoforms of nitric oxide synthase, (30 mg/kg, s.c.) followed by ethanol 3 h later; and (c) L-NAME (30 mg/kg, s.c.) followed by saline 3 h later. Saline-injected and untreated rats were used as controls. The animals were sacrificed 0.5 h after ethanol administration. Intestinal expression of IgA was evaluated by both immunohistochemistry and Western immunoblotting. Morphometric analysis showed that acute ethanol treatment increased the number of IgA-immunoreactive cells in a dose-dependent manner. Pretreatment with L-NAME abolished this action of alcohol. Injection of L-NAME followed by saline had no influence on the number of IgA+cells. The results, obtained by Western immunoblotting, paralleled our immunohistochemical findings. Taken together, these data suggest that acute effect of ethanol on intestinal IgA might be mediated by endogenous nitric oxide.

Serotonin-producing enterochromaffin (EC) cells of gastrointestinal mucosa in dexamethasone-treated rats.

The aim of our study was to investigate the morphological, immunohistochemical and ultrastructural changes of rat serotonin-producing enterochromaffin (EC) cells of gastrointestinal mucosa in dexamethasone-treated rats (D). After 12-daily intraperitoneal administration of 2 mg/kg dexamethasone, rats developed diabetes similar to human diabetes type 2. Stomach, small and large intestines were examined. Large serotonin positive EC cells appeared in the corpus mucosa epithelium of D group of rats, although these cells were not present in control (C) rats. Both volume fraction and the number of EC cells per mm(2) of mucosa were significantly increased only in the duodenum. However, the number of EC cells per circular sections of both antrum and small intestine was increased, but reduced both in the ascending and descending colon in D group. The dexamethasone treatment caused a strong reduction in number of granules in the antral EC cells, while it was gradually increased beginning from the jejunum to descending colon. The mean granular content was reduced in the antral EC cells but increased in the jejunal EC cells in D group. In conclusion, the present study showed that morphological changes in gut serotonin-producing EC cells occurred in diabetic rats.

Expression of cytokeratins in Helicobacter pylori-associated chronic gastritis of adult patients infected with cagA+ strains: an immunohistochemical study.

AIM: To investigate the expression of different cytokeratins (CKs) in gastric epithelium of adult patients with chronic gastritis infected with Helicobacter pylori (H pylori) cagA+ strains. METHODS: The expression of CK 7, 8, 18, 19 and 20 was studied immunohistochemically in antral gastric biopsies of 84 patients. All the CKs were immunostained in cagA+H pylori gastritis (57 cases), non-H pylori gastritis (17 cases) and normal gastric mucosa (10 cases). RESULTS: In cagA+ H pylori gastritis, CK8 was expressed comparably to the normal antral mucosa from surface epithelium to deep glands. Distribution of CK18 and CK 19 was unchanged, i.e. transmucosal, but intensity of the expression was different in foveolar region in comparison to normal gastric mucosa. Cytokeratin 18 immunoreactivity was significantly higher in the foveolar epithelium of H pylori-positive gastritis compared to both H pylori-negative gastritis and controls. On the contrary, decrease in CK19 immunoreactivity occurred in foveolar epithelium of H pylori-positive gastritis. In both normal and inflamed antral mucosa without H pylori infection, CK20 was expressed strongly/moderately and homogeneously in surface epithelium and upper foveolar region, but in H pylori -induced gastritis significant decrease of expression in foveolar region was noted. Generally, in both normal antral mucosa and H pylori-negative gastritis, expression of CK7 was not observed, while in about half cagA+ H pylori-infected patients, moderate focal CK7 immunoreactivity of the neck and coiled gland areas was registered, especially in areas with more severe inflammatory infiltrate. CONCLUSION: Alterations in expression of CK 7, 18, 19 and 20 together with normal expression of CK8 occur in antral mucosa of H pylori-associated chronic gastritis in adult patients infected with cagA+ strains. Alterations in different cytokeratins expression might contribute to weakening of epithelial tight junctions observed in H pylori-infected gastric mucosa.

Gastrin and antral G cells in course of Helicobacter pylori eradication: six months follow up study.

AIM: To assess long-term effects of Helicobacter pylori (H pylori) eradication on antral G cell morphology and function in patients with and without duodenal ulcer (DU). METHODS: Consecutive dyspeptic patients referred to the endoscopy entered the study. Out of 39 H pylori positive patients, 8 had DU (H pylori +DU) and 31 gastritis (H pylori +G). Control groups consisted of 11 uninfected dyspeptic patients (CG1) and 7 healthy volunteers (CG2). Basal plasma gastrin (PGL), antral tissue gastrin concentrations (ATGC), immunohistochemical and electron microscopic characteristics of G cells were determined, prior to and 6 mo after therapy. RESULTS: We demonstrated elevated PGL in infected patients compared to uninfected controls prior to therapy. Elevated PGL were registered in all H pylori+patients (H pylori +DU: 106.78+/-22.72 pg/mL, H pylori +G: 74.95+/-15.63, CG1: 68.59+/-17.97, CG2: 39.24+/-5.59 pg/mL, P<0.01). Successful eradication (e) therapy in H pylori+patients lead to significant decrease in PGL (H pylori+DU: 59.93+/-9.40 and H pylori +Ge: 42.36+/-10.28 pg/mL, P<0.001). ATGC at the beginning of the study were similar in infected and uninfected patients and eradication therapy lead to significant decrease in ATGC in H pylori +gastritis, but not in DU patients. In the H pylori +DU patients, the mean number of antral G cells was significantly lower in comparison with all other groups (P<0.01), but after successful eradication was close to normal values found in controls. By contrast, G cell number and volume density were significantly decreased (P<0.01) in H pylori +Ge group after successful eradication therapy (294+/-32 and 0.31+/-0.02, respectively), in comparison to values before eradication (416+/-40 and 0.48+/-0.09). No significant change of the G cell/total endocrine cell ratio was observed during the 6 mo of follow up in any of the groups. A reversible increase in G cell secretory function was seen in all infected individuals, demonstrated by a more prominent secretory apparatus. However, differences between DU and gastritis group were identified. CONCLUSION: H pylori infection induces antral G cell hyperfunction resulting in increased gastrin synthesis and secretion. After eradication therapy complete morphological and functional recovery is observed in patients with gastritis. In the DU patients some other factors unrelated to the H pylori infection influence antral G cell morphology and function.

Acute effect of ethanol on IgA immunoreactive cells in the intestine-associated immune system.

The purpose of this study was to investigate the acute effect of ethanol on mucosa-associated lymphoid tissue at the level of Peyer's patches and the intestinal lamina propria in female rats and to determine whether this action of ethanol is modulated during the estrous cycle. Adult female rats showing proestrus or diestrus day 1 were treated intraperitoneally (ip) with ethanol (4 g/kg). Untreated and saline-injected rats were used as controls. The animals were sacrificed by decapitation 0.5 h after ethanol administration. Immunoglobulin A (IgA) immunoreactive cells were analyzed by indirect immunohistochemistry using mouse anti-rat IgA and a Dako LSAB+ kit. The number of IgA-immunoreactive cells in Peyer's patches was unaltered by ethanol treatment at both phases of the estrous cycle. However, stereological analysis revealed a significant increase in the number of IgA-immunoreactive cells (p < 0.01) in the intestinal lamina propria following acute ethanol administration at proestrus and on diestrus day 1. The results indicate that the intestinal lamina propria, the effector site of the mucosal immune system, can be affected by a single dose of ethanol at both phases of the estrous cycle.

Somatostatin and D cells in patients with gastritis in the course of Helicobacter pylori eradication: a six-month, follow-up study.

BACKGROUND/AIMS: As well as causing chronic gastritis, Helicobacter pylori predisposes patients to peptic ulcer disease and gastric cancer, and induces gastric functional disorders. The aim of our study was to investigate the effects of H. pylori eradication therapy on the morphological and functional recovery of gastric antral and corpus D cells in patients with chronic gastritis during 6 months of follow-up. PATIENTS AND METHODS: Forty consecutive, dyspeptic patients referred for endoscopy (31 with H. pylori infection and nine controls; mean age 49 years; 17 men, 23 women) entered the study. All patients had histological signs of gastritis but no signs of peptic ulcer or gastric cancer. Antrum (n=8) and corpus (n=6) biopsy specimens were collected for routine histology, radioimmunoassay tissue somatostatin levels, immunohistochemistry and electron microscopy, prior to and 6 months after therapy. Basal plasma somatostatin levels were determined prior to eradication, plus 6 weeks and 6 months after therapy. Eradication therapy consisted of amoxicillin, metronidazole and omeprazole. RESULTS: Basal somatostatin plasma values in antral and corpus tissue were lower in infected patients than in the H. pylori-negative controls at the beginning of the study. A significant increase occurred after successful eradication therapy, together with an increase in the number of D cells in both regions. Changes in the D-cell ultrastructure in antral and corpus mucosa after eradication therapy suggest an increase in somatostatin synthesis and secretion. CONCLUSIONS: The structural and functional restoration of D cells following eradication therapy indicates possible recovery of the diseased mucosa.

Characterization of deciduous teeth stem cells isolated from crown dental pulp.

BACKGROUND/AIM: The last decade has been profoundly marked by persistent attempts to use ex vivo expanded and manipulated mesenchymal stem cells (MSCs), as a tool in different types of regenerative therapy. In the present study we described immunophenotype and the proliferative and differentiation potential of cells isolated from pulp remnants of exfoliated deciduous teeth in the final phase of root resorption. METHODS: The initial adherent cell population from five donors was obtained by the outgrowth method. Colony forming unit-fibroblast (CFU-F) assay was performed in passage one. Cell expansion was performed until passage three and all tests were done until passage eight. Cells were labeled for early mesenchymal stem cells markers and analysis have been done using flow cytometry. The proliferative potential was assessed by cell counting in defined time points and population doubling time was calculated. Commercial media were used to induce osteoblastic, chondrogenic and adipogenic differentiation. Cytology and histology methods were used for analysis of differentiated cell morphology and extracellular matrix characteristics. RESULTS: According to immunophenotype analyses all undifferentiated cells were positive for the mesenchymal stem cell markers: CD29 and CD73. Some cells expressed CD146 and CD106. The hematopoietic cell marker, CD34, was not detected. In passage one, incidence of CFU-F was 4.7 +/- 0.5/100. Population doubling time did not change significantly during cell subcultivation and was in average 25 h. After induction of differentiation, the multicolony derived cell population had a tri-lineage differentiation potential, since mineralized matrix, cartilage-like tissue and adipocytes were successfully formed after three weeks of incubation. CONCLUSION: Altogether, these data suggest that remnants of deciduous teeth dental pulp contained cell populations with mesenchymal stem cell-like features, with a high proliferation and tri-lineage differentiation potential and that these cultures are suitable for further in vitro evaluation of cell based therapies.

Ethanol and nitric oxide modulate expression of glucocorticoid receptor in the rat adrenal cortex.

BACKGROUND: This study was performed to investigate expression and distribution of glucocorticoid receptor (GR) in the rat adrenal cortex, acute effect of ethanol on its expression and possible role of endogenous nitric oxide (NO) in this phenomenon. METHODS: Adult female Wistar rats showing diestrus day 1 were treated with: a) ethanol (2 or 4 g/kg body weight (b.w.), ip), b) N(ω)-nitro-L-arginine methyl ester (L-NAME), well-known competitive inhibitor of all isoforms of NO synthase (NOS), (30 mg/kg b.w., sc) followed by ethanol (4 g/kg, ip) 3 h later and c) L-NAME (30 mg/kg b.w., sc) followed by saline (ip) 3 h later. Untreated rats were used as controls. Adrenocortical expression of GR was estimated by immunohistochemistry. RESULTS: Strong nuclear GR staining was observed throughout the cortex of control rats. Acute ethanol treatment significantly decreased the expression of GR in the zona fasciculata and zona reticularis. Blockade of NO formation had no influence on this effect of ethanol, whereas L-NAME itself induced significant decline in GR immunoreactivity. CONCLUSIONS: Obtained findings are the first to demonstrate localization and distribution of the GR throughout the rat adrenal cortex and to suggest that ethanol as well as endogenous NO may modulate adrenocortical expression of this steroid receptor.

Large cell lung carcinoma with unusual imaging feature, immunophenotype and genetic finding.

We present a case of large cell lung carcinoma in sixty-one year old male with typical lung cancer symptoms but unusual radiological presentation and immunophenotype. Tumor morphological finding related to its radiological finding was suggestive for large cell lymphoma or carcinoma, but its immunophenotype made confusion for pathological diagnosis. No p53 mutations were detected in genetic investigation. Multidisciplinary diagnostic approach to some tumors is useful for their final diagnosis.

The trigeminal vasculature pathology in patients with neuralgia.

OBJECTIVE: To examine the possible pathological changes of the trigeminal vasculature in patients with neuralgia. BACKGROUND: Such a study has never been performed before. The alterations of the trigeminal vessels could have important pathophysiological implications in the trigeminal neuralgia pathogenesis. METHODS: The biopsy specimens for the electronmicroscopic (EM) and immunohistochemical examination were taken during a partial rhizotomy in 6 patients with trigeminal neuralgia and in 2 persons with trigeminal neuropathy. In addition, the 32 normal trigeminal nerves were used as the control specimens. RESULTS: The vascular pathological alterations were noticed in 3 out of 6 neuralgia patients. The EM study revealed signs of apoptosis or degeneration, respectively, of some endothelial and smooth muscle cells in the wall of the trigeminal arterioles. The immune reactions against CD31, CD34, and alpha-smooth muscle actin in these cells were weaker than in the control specimens, but stronger against factor VIII. In addition, the arteriolar basement membranes, which were thickened, showed an intense laminin, fibronectin, and collagen IV immunoreactivity. Similarly, some endothelial cells and pericytes of the intratrigeminal capillaries also showed signs of apoptosis or degeneration, respectively. Their basement membrane was very thick and showed an intense immune reaction against laminin, fibronectin, and collagen IV. CONCLUSION: The observed pathological changes of the trigeminal vasculature could be the primary factor, while demyelination of the trigeminal nerve fibers could be the secondary process in some patients with neuralgia.

Soft tissue myoepithelial carcinoma.

BACKGROUND: Myoepitheliomas are tumors composed predominantly or exclusively of myoepithelial cells, usually arising in salivary glands. Cutaneous/soft tissue localization is very rare, especially for the malignant myoepitheliomas. CASE REPORT: We presented a case of myoepithelial carcinoma involving subcutaneous adipose tissue of the left forearm in a woman aged 62 years. The tumor was composed of epithelioid and hyaline cell types, arranged in diffuse sheets, nests and loose clusters within hyalinized and myxoid matrix. The neoplasm displayed high-grade cytologic atypia with some cells having pleomorphic, hyperchromatic nuclei, and others showing vesicular nuclei, large nucleoli with scattered bizarre giant cells. High mean mitotic count of 7 mitoses/10 high power filds and extensive necrosis favoured the diagnosis of malignancy. Immunohistochemical staining was positive for cytokeratin (AE1/AE3), epithelial membrane antigen, S-100 protein, glial fibrillary acidic protein, and vimentin. CONCLUSION: Considering the subcutaneous localization, myoepithelial immunophenotype and high-grade cytologic atypia the neoplasm was classified as a soft-tissue myoepithelial carcinoma.