The characteristics of Polish patients with salivary gland tumors: a ten-year single-center experience.

OBJECTIVES: The study aims to provide insights into the characteristics of Polish patients with different salivary gland pathologies. MATERIALS AND METHODS: This is a retrospective study conducted at a single center, including patients who underwent surgery for salivary gland pathologies between 2012 and 2022. RESULTS: This study included 239 patients who underwent surgery for salivary gland tumors or inflammatory diseases. Malignant tumors were diagnosed in 9.8% of participants, while 64% had benign tumors and 21% suffered from inflammation. The occurrence of complications after surgery was relatively low, with 9.9% of participants experiencing slight facial weakness or mild dysfunction, and 3% experiencing complete paralysis of the facial nerves. Significant differences were observed between patients with cancers and those with benign tumors and inflammation in terms of age. Cancers were more common in females (67% vs. 33%) and predominantly localized in the parotid glands (95%). CONCLUSION: Benign tumors, such as Warthin's tumors and polymorphous adenoma, were predominantly found in the parotid glands of patients aged 39-72 years. On the other hand, inflammatory diseases were primarily localized within the submandibular glands of males aged 40-68 years. Additionally, the presence of a malignant tumor was associated with longer hospitalization periods related to surgery and a higher risk of severe complications. CLINICAL RELEVANCE: This study on Polish patients with salivary gland tumors provides valuable clinical insights that can aid in diagnosis, treatment planning, patient counseling, and further research in the field of oncology. It contributes to the overall understanding of salivary gland tumors, potentially benefiting both patients and healthcare providers.

Concordance between Clinical and Pathological T and N Stages in Polish Patients with Head and Neck Cancers.

BACKGROUND: The TNM (tumor, node, metastasis) staging system is important for the successful treatment of head and neck cancers (HNCs). This study aimed to evaluate the concordance between clinical and pathological T and N stages in patients with HNCs in Poland. METHODS: In this single-center retrospective study, clinical and pathological TNM staging data on 203 patients undergoing surgical treatment for HNC between 2011 and 2018 were collected and compared. The study group was classified as underdiagnosed, overdiagnosed, or correctly diagnosed with HNC based on pathological TNM staging. The concordance between clinical and pathological staging was evaluated using the kappa coefficient. RESULTS: Clinical and pathological TNM staging showed concordance in 59.9% of patients for primary tumor (T) and in 79.3% of patients for lymph node (N) classifications. Moderate agreement between the clinical and pathological stages was shown for stage T, while substantial agreement was revealed for stage N. The size and extent of the tumor were underestimated or overestimated in 73 of the 182 patients (40.1%), while lymph node involvement was downstaged in 11 of the 53 patients (20.7%). CONCLUSIONS: The disparities between clinical and pathological staging of HNC demonstrate the need for standardization in physical and pathological examinations, as well as radiographic imaging.

Occurrence of IL-1, IL-10, CD25, CD40, and CD69 in the tissue of palatine tonsils.

Introduction: Palatine tonsil disease often coexists with dermatological diseases. Correct diagnosis of inflammation of the palatine tonsil tissue and removal of the diseased palatine tonsils results in remission of the disease. Aim: To determine similarities and differences in the immunohistochemistry profile of the palatine tonsil tissue between tonsillitis and hypertrophy, including location of the immunohistochemistry reactions in specific histological sites. Material and methods: A prospective analysis of 50 palatine tonsils that had undergone tonsillectomy due to tonsillitis (30 cases) and hypertrophy (20 cases) was performed. The collected material underwent immunohistochemistry staining for: IL-1, IL-10, CD25, CD40, and CD69, and subsequently phenotypic expression of the obtained results was performed including their histological location. Results: Statistically significant differences (p < 0.05) between the tonsillitis and hypertrophy groups were found for almost all IHC reactions in the epithelium covering the tonsils for CD-25, CD-69, IL-1, IL-10. Furthermore, significant differences between these groups were found for IL-10 reaction in the subepithelial inflammatory infiltrate and follicular centres of lymphatic follicles as well as for CD-69 reaction between the follicles. When all the locations were summarized, significant (p < 0.05) differences were found for all IHC reactions except for CD-40. Conclusions: The investigated markers and cytokines: CD25 and CD69, and IL-1 and IL-10 are more abundant in tonsillitis than in hypertrophy of the palatine tonsils.

Oilseed rape (Brassica napus): the importance of aminopeptidases in germination under normal and heavy metals stress conditions.

BACKGROUND: Oilseed rape is one of the most important oilseed crops worldwide, crucial in the food and feed industries. Different environment and climatic conditions can influence its sustainable cultivation and crop yield. Aminopeptidases are crucial enzymes in many physiological processes in all organisms, including humans, so it is important to learn their behavior in food and feed sources. This study presents, for the first time, a detailed discussion on the importance of aminopeptidases, during the oilseed rape germination process, under standard and stress conditions. RESULTS: During the germination of oilseed rape under standard conditions, a significant increase in aminopeptidases activity toward N-terminal amino acids - phenylalanine (Phe), alanine (Ala), glycine (Gly), leucine (Leu), proline (Pro), methionine (Met) - was observed. The change was substrate specific, with the highest increase being observed for Gly (3.2-fold), followed by Ala (2.9-fold), Pro (2.5-fold), Met (1.5-fold), and Phe (1.3-fold). Generally, N-terminal Phe was preferentially cleaved. Germination under stress conditions, caused by several heavy metal ions (e.g. divalent copper, zinc, cadmium, and lead ions), negatively influenced the plants' growth and quality, but significantly enhanced the expression of genes encoding aminopeptidases (or potentially activated aminopeptidases precursors), which was related to the dramatic increase of their activity. CONCLUSIONS: The activity/concentration of aminopeptidases in plants is adjusted to the needs at each stage of development and stress factors occurrence. The most significant increase of activity toward N-terminal Gly and Pro proved the key role of aminopeptidases in the defense mechanisms, by supplying the plants with osmoprotectants and organic nitrogen. The results provide new concepts of oilseed rape growth and cultivation under different conditions. © 2021 Society of Chemical Industry.

Tonsillectomy in own material.

<b>Introduction:</b> Tonsillectomy belongs to the most frequently performed surgical treatments; however, the necessity of its performance is questioned. Therefore, there are many attempts to unify and define the indications for the procedure. <br><b>Aim:</b> The main objective of the current dissertation was an analysis of the clinical symptoms occurring in patients qualified for tonsillectomy, as well as a comparison of those with a histopathological image of the removed tonsils in a repeatedly carried out, unified pathomorphological examination. The secondary objective was the designation of the demographic profile, existing comorbidities, and complications in the form of postoperative bleeding in patients after tonsillectomy in own material. <br><b>Material and method:</b> A retrospective analysis of 301 procedures of palatine tonsil removal was performed, which were completed in the years 2017-2019 at the Department of Otolaryngology with Division of Cranio-Maxillo-Facial Surgery of the Military Institute of Medicine, Warsaw, Poland. The indications were defined on the grounds of data from the anamnesis. Based on unified criteria, the removed material was divided into 2 groups: with the signs of Chronic Tonsillitis (CT) as well as Tonsillar Hyperthrophy (TH). <br><b>Results:</b> The average size of tonsils was the greatest in a group of patients under 35 years of age, and smallest in the group over 51 years of age. As patients aged, the reduction in size of the palatal tonsils was observed. In the examined group, the histopathological diagnosis in the form of HT was found in 165 patients (54.8%), while CT in 136 (45.2%). It was proven that the larger the tonsils in the clinical picture, the more often the histopathological image responded to HT. Among clinical symptoms reported by patients qualified for tonsillectomy, the following were observed: recurring tonsil inflammation in 211 (70.1%), snoring and sleep apnea in 47 (15.6%), as well as sleep apnea in 33 (11%) patients. Primary bleeding occurred in 10 patients (3.34%), and secondary in 8 patients (2.66%). The most common comorbidities were cardiovascular burdens. <br><b>Conclusions:</b> For most cases, clinical symptoms were confirmed by adequate features of removed material in histopathological examination. The most common histopathological diagnosis was tonsillar hyperthrophy.

The influence of chosen fungicides on the activity of aminopeptidases in winter oilseed rape during pods development.

Cultivation of oilseed rape requires application of specific fungicides. Besides their protective role, they can potentially influence the expression and activity of crucial enzymes in the plant. Among the large number of enzymes expressed in plants, aminopeptidases play a key role in all crucial physiological processes during the whole life cycle (e.g. storage protein mobilization and thus supplying plant with needed amino acids, as well as plant aging, protection and defense responses). In the present paper, we evaluate for the first time, the influence of the treatment of winter oilseed rape with commercially available fungicides (Pictor 400 SC, Propulse 250 SE and Symetra 325 SC), on the activity of aminopeptidases expressed in each plant organ (flowers, leaves, stems and pods separately). Fungicides were applied once, at one of the three stages of oilseed rape development (BBCH 59-61, BBCH 63-65 and BBCH 67-69). The aminopeptidase activity was determined using six different amino acid p-nitroanilides as substrates. The results have shown, that in control plants, at the beginning of intensive pods development and seeds production, hydrophobic amino acids with bulky side chains (Phe, Leu) were preferentially hydrolysed. In control plants, the activity was ~3.5 times higher in stems and pods, compared to leaves. The treatment with all pesticides caused significant increase in aminopeptidases hydrolytic activity toward small amino acids Gly, Ala as well as proline, mostly in flowers and leaves. These amino acids are proven to be crucial in the mechanisms of delaying of plant aging, development of better resistance to stress and plant defense. It can be suggested, that studied fungicides enhance such mechanisms, by activating the expression of genes coding for aminopeptidases, which are active in hydrolysis of N-terminal amino acids such as Gly, Ala, Pro from storage peptides and proteins. Depending on fungicide, the major increase of aminopeptidase activity was observed after application at BBCH 67-69 (Pictor 400 SC and Symetra 325 SC) and BBCH 63-65 (Propulse 250 SE) stages of development. Our study revealed, that agrochemical treatment and time of application, influenced the expression and activity of aminopeptidases, even though they were not molecular targets of applied fungicides. Since aminopeptidases are widely distributed throughout all organisms and are crucial in many key physiological processes, it can be expected, that factors influencing their expression and activity in plants, can also influence these enzymes in other organisms, especially humans and other mammals.

Hepatocyte growth factor acts as a mitogen for equine satellite cells via protein kinase C δ-directed signaling.

Hepatocyte growth factor (HGF) signals mediate mouse skeletal muscle stem cell, or satellite cell (SC), reentry into the cell cycle and myoblast proliferation. Because the athletic horse experiences exercise-induced muscle damage, the objective of the experiment was to determine the effect of HGF on equine SC (eqSC) bioactivity. Fresh isolates of adult eqSC were incubated with increasing concentrations of HGF and the initial time to DNA synthesis was measured. Media supplementation with HGF did not shorten (P > 0.05) the duration of G0/G1 transition suggesting the growth factor does not affect activation. Treatment with 25 ng/mL HGF increased (P < 0.05) eqSC proliferation that was coincident with phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and AKT serine/threonine kinase 1 (AKT1). Chemical inhibition of the upstream effectors of ERK1/2 or AKT1 elicited no effect (P > 0.05) on HGF-mediated 5-ethynyl-2'-deoxyuridine (EdU) incorporation. By contrast, treatment of eqSC with 2 µm Gö6983, a pan-protein kinase C (PKC) inhibitor, blocked (P < 0.05) HGF-initiated mitotic activity. Gene-expression analysis revealed that eqSC express PKCα, PKCδ, and PKCε isoforms. Knockdown of PKCδ with a small interfering RNA (siRNA) prevented (P > 0.05) HGF-mediated EdU incorporation. The siPKCδ was specific to the kinase and did not affect (P > 0.05) expression of either PKCα or PKCε. Treatment of confluent eqSC with 25 ng/mL HGF suppressed (P < 0.05) nuclear myogenin expression during the early stages of differentiation. These results demonstrate that HGF may not affect activation but can act as a mitogen and modest suppressor of differentiation.

Characterisation of the aminopeptidase from non-germinated winter rape (Brassica napus L.) seeds.

Rapeseed plays a crucial role in food and fuel industry. Since aminopeptidases take part in many physiological processes in all organisms, it is important to learn their role and characteristics in economically relevant plants. Extracts of non-germinated winter rape seeds were screened for aminopeptidase activity. Substrate specificity, the influence of pH and temperature, as well as effect of protease inhibitors and chosen metal ions on the aminopeptidase activity were determined. The approximate molecular weight estimated by NATIVE-PAGE and SDS-PAGE electrophoresis was ∼60 kDa. The partially purified enzyme as well as the aminopeptidases present in crude extract cleaved preferentially Phe-pNA. The activity profiles toward several substrates were also determined. Maximum activity was observed at pH 6.5 and temperature of 40 °C for Phe-pNA as a substrate. Two visible picks in the pH profile toward Phe-pNA, together with other results (IEF) suggest the presence of more than one aminopeptidase, having similar molecular mass. Much lower activity and broad pH profiles were observed for Leu- and Ala-pNA as substrates.

Esophagoprotection mediated by exogenous and endogenous melatonin in an experimental model of reflux esophagitis.

Reflux esophagitis is a common clinical entity in western countries with approximately 30% of the population experiencing the symptoms at least once every month. The imbalance between the protective and aggressive factors leads to inflammation and damage of the esophageal mucosa. We compared the effect of exogenous melatonin and melatonin derived endogenously from L-tryptophan with that of pantoprazole or ranitidine in acid reflux esophagitis due to ligation of the rat pylorus and the limiting ridge between the forestomach and the corpus. Four hours after the induction of gastric reflux, an increase in mucosal lesions associated with edema of the submucosa and with the infiltration of numerous neutrophils and the fall in esophageal blood flow (EBF) were observed. Both melatonin and L-tryptophan or pantoprazole significantly reduced the lesion index (LI) and raised the EBF. Pinealectomy that significantly decreased plasma melatonin levels aggravated LI and these effects were reduced by melatonin and L-tryptophan. Luzindole, the MT2 receptor antagonist, abolished the melatonin-induced reduction in LI and the rise in EBF. L-NNA and capsaicin that augmented LI and decreased EBF, also significantly reduced melatonin-induced protection and hyperemia; both were restored with L-arginine and calcitonin gene-related peptide (CGRP) added to melatonin. Upregulation of IL-1ß and TNF-α mRNAs and plasma IL-1ß and TNF-α levels were significantly attenuated by melatonin and L-tryptophan. We conclude that melatonin protects against acid reflux-induced damage via activation of MT2 receptors mediated by NO and CGRP released from sensory nerves and the suppression of expression and release of TNF-α and IL-1ß.

Crystal structures of the coil 2B fragment and the globular tail domain of human lamin B1.

We present here the crystal structures of human lamin B1 globular tail domain and coiled 2B domain, which adopt similar folds to Ig-like domain and coiled-coil domain of lamin A, respectively. Despite the overall similarity, we found an extra intermolecular disulfide bond in the lamin B1 coil 2B domain, which does not exist in lamin A/C. In addition, the structural analysis indicates that interactions at the lamin B1 homodimer interface are quite different from those of lamin A/C. Thus our research not only reveals the diversely formed homodimers among lamin family members, but also sheds light on understanding the important roles of lamin B1 in forming the nuclear lamina matrix.

Effect of vitamin C-releasing acetylsalicylic acid on gastric mucosal damage before and after Helicobacter pylori eradication therapy.

The interaction between Helicobacter pylori (H. pylori) and nonsteroidal anti-inflammatory drugs (NSAIDs) such as acetylsalicylic acid is still controversial. This study was designed to compare the effect of acetylsalicylic acid and vitamin C-releasing acetylsalicylic acid on the gastric mucosal damage and microbleeding before and after eradication of H. pylori in 10 young healthy volunteers. Acetylsalicylic acid induced significantly more gastric lesions and higher microbleeding than acetylsalicylic acid-vitamin C. After successful H. pylori eradication therapy, acetylsalicylic acid induced significantly higher mucosal lesions and microbleeding than before eradication. In contrast, after acetylsalicylic acid-vitamin C, gastric lesion index was significantly lower and eradication therapy failed to aggravate it. All H. pylori-positive subjects showed significant up-regulation of antioxidant enzyme (superoxide dismutase, catalase, glutathione peroxidase). Plain acetylsalicylic acid stronger than acetylsalicylic acid-vitamin C reduced gastric gene expression of these antioxidant enzymes. H. pylori eradication significantly decreased expression of these enzymes and this was further enhanced by plain acetylsalicylic acid, but not acetylsalicylic acid-vitamin C. Under plain acetylsalicylic acid therapy, the expression of proinflammatory cytokines was increased before and after eradication of H. pylori. We conclude that vitamin C combined with acetylsalicylic acid, unlike plain acetylsalicylic acid without vitamin C, protects gastric mucosa in man probably due the attenuation of oxidative stress and proinflammatory cytokines.

Implication of peroxisome proliferator-activated receptor gamma and proinflammatory cytokines in gastric carcinogenesis: link to Helicobacter pylori-infection.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-dependent transcription factor involved in various processes including the inflammation and carcinogenesis. The aim of the present study was 1) to examine the mRNA and protein expression of PPARgamma in gastric cancer (GC); 2) to evaluate the effect of PPARgamma ligand (ciglitazone) on the proliferation and apoptosis of GC cell line; and 3) to assess the levels of gastric tissue proinflammatory cytokines, IL-1beta and IL-8, and plasma gastrin in GC patients before and after Helicobacter pylori (H. pylori) eradication. The trial material included 30 H. pylori-negative controls and 30 sex- and age-matched GC patients without or with H. pylori before and after its eradication. Expression of tissue PPARgamma, tissue levels of IL-1beta and IL-8, and plasma concentration of gastrin were significantly higher in H. pylori-positive GC compared to controls, but H. pylori eradication significantly reduced these parameters. Kato III cells incubated with alive H. pylori upregulated PPARgamma expression and ciglitazone inhibited cell proliferation and induced apoptosis. PPARgamma, proinflammatory cytokines and plasma gastrin appear to be implicated in H. pylori-related gastric carcinogenesis and PPARgamma agonists may have potential in cancer therapy.

Activation of NFkappaB represents the central event in the neoplastic progression associated with Barrett's esophagus: a possible link to the inflammation and overexpression of COX-2, PPARgamma and growth factors.

The molecular mechanisms responsible for the progression of malignant transformation in Barrett's esophagus (BE) are still poorly understood. This study was undertaken (1) to investigate the gene and protein expression of cyclooxygenase-2 (COX-2), peroxisome proliferator-activated receptor-gamma (PPARgamma), interleukin-8 (IL-8), hepatocyte growth factor (HGF), gastrin, and its receptor (CCK-2) in the Barrett's epithelium; (2) to analyze the activity of NFkappaB in Barrett's esophagus with low-grade dysplasia; and (3) to assess the effects of PPARgamma ligand (ciglitazone) and gastrin on cell proliferation in the cell line derived from esophageal adenocarcinoma (OE-33). COX-2, PPARgamma, IL-8, HGF, gastrin, and CCK-2 expression levels relative to the control gene encoding GAPDH were analyzed by RT-PCR and Western blot in specimens of BE with low-grade dysplasia (n = 20) and compared with that in the normal squamous esophageal mucosa from the middle portion of the esophagus (n = 20). In vitro experiments included the incubation of cell line OE-33 with ciglitazone (1-15 microM) and gastrin (100 nM). NFkappaB activity in biopsies specimens was measured by highly sensitive ELISA. COX-2, PPARgamma, IL-8, HGF, gastrin, and CCK-2 expressions were significantly increased in BE compared with normal squamous esophageal mucosa. NFkappaB activity was significantly upregulated in BE. Ciglitazone inhibited cell proliferation of OE-33 cells as assessed by BrdU and this effect was attenuated partly by gastrin. (1) COX-2, PPARgamma, HGF, gastrin, and its receptor are significantly upregulated in BE, suggesting a possible role for these factors in Barrett's carcinogenesis; (2) the increased NFkappaB activity is probably linked to increased IL-8 and COX-2 expression; and (3) PPARgamma ligands might be useful as a new therapeutic option in the prevention and treatment of Barrett's carcinoma.

Cytokine action and oxidative stress response in differentiated neuroblastoma SH-SY5Y cells.

In the retinoic acid-differentiated neuroblastoma SH-SY5Y cells, IL-1 induced binding activity of NFkappaB and up-regulated the expression and activity of MnSOD. The IL-1-elicited effects were partly reversed by IL-4 and IL-6. It is proposed that IL-4 and IL-6 may participate in the regulation of the imbalanced oxidant status induced by IL-1 in differentiated neuroblastoma cells. In the SH-SY5Y cell line, TNFalpha neither activated NFkappaB nor induced MnSOD expression and activity, but was capable of modulating the IL-1 effects. Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NFkappaB activation, down-regulated the expression and activity of MnSOD, which may suggest that the regulation of MnSOD by IL-1 in retinoic acid-differentiated neuroblastoma cells was mediated by the nuclear factor kappaB.

H. pylori infection, atrophic gastritis, cytokines, gastrin, COX-2, PPAR gamma and impaired apoptosis in gastric carcinogenesis.

BACKGROUND: Helicobacter pylori (Hp) infection represents a crucial factor in pathogenesis of gastric cancer (GC). Factors emanating from bacterium as well as from environmental contributions such as salt diet and inadequate supply of antioxidants, affect the risk for GC development. RESULTS: Atrophic gastritis is considered to be a precursor lesion of intestinal type GC that is accompanied by hypergastrinemia with subsequent induction of cyclooxygenase-2 (COX-2), whose products are responsible for slowing apoptosis and for angiogenesis in GC tumor. The involvement of proinflammatory cytokines (especially IL-1 and IL-8) and reactive oxygen species (ROS) due to NF kappa B activation, increased cell proliferation combined with inhibition of apoptosis as well as upregulation of peroxisome proliferation activated receptor gamma (PPAR gamma) and inducible nitric oxide synthase (iNOS) appear to be major molecular biology alterations in pathogenesis of GC. CONCLUSIONS: These results suggest the therapeutic usefulness of inhibitors of gastrin expression and release such as powerful somatostatin analogs (Sandostatin) or blockers of COX-2 (coxibs) in the control of GC development and progression as chemopreventive agents. Comparative genomic and proteomic is the key in identifying biomarkers in host and bacterium for the prediction of gastric cancer in Hp-infected patients.

Pioglitazone, a specific ligand of peroxisome proliferator-activated receptor-gamma, accelerates gastric ulcer healing in rat.

The peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a member of the nuclear hormone receptor superfamily that is involved in the control of inflammation and carcinogenesis. We determined the effect of the specific PPAR-gamma ligand, pioglitazone (5-40 mg/kg intragastrically), on the healing of acetic-acid gastric ulcers in rats. At day 8 after ulcer induction, the ulcer area, the gastric blood flow and mucosal expression of proinflammatory cytokines such as interleukin-1beta, tumour necrosis factor alpha (TNF-alpha) and cyclooxygenase-1, cyclooxygenase-2, constitutive nitric oxide synthase (cNOS), inducible nitric oxide synthase (iNOS) and heat shock protein 70 (HSP70) was determined. Pioglitazone reduced the area of gastric ulcers and raised significantly the gastric blood flow at the ulcer margin and downregulated the mRNA for interleukin-1beta, TNF-alpha, cyclooxygenase-2 and iNOS while cyclooxygenase-1 mRNA was not affected. The expression of PPAR-gamma mRNA was increased in the ulcerated gastric mucosa. We conclude that pioglitazone accelerates the healing of preexisting gastric ulcers due to the hyperemia at ulcer margin and the anti-inflammatory action including suppression of interleukin-1beta, TNF-alpha, cyclooxygenase-2 and iNOS and by an overexpression of HSP70.

Nitric oxide releasing aspirin protects the gastric mucosa against stress and promotes healing of stress-induced gastric mucosal damage: role of heat shock protein 70.

BACKGROUND/AIM: Nitric oxide (NO) releasing nonsteroidal anti-inflammatory drugs do not cause gastric mucosal damage, despite inhibition of the cyclooxygenase activity to a similar extent as conventional nonsteroidal anti-inflammatory drugs that induce such damage. We compared the effects of native aspirin (ASA) with those of NO-releasing ASA (NO-ASA) on the development and healing of acute gastric lesions induced by water immersion and restraint stress (WRS) and the mucosal expression of heat shock protein 70 (HSP70). METHODS: Wistar rats received: (1). vehicle; (2). ASA (40 mg/kg i.g), and (3). NO-ASA (2.5-40 mg/kg i.g.), followed 0.5 h later by 3.5 h of WRS with or without glyceryl trinitrate, the donor of NO, and carboxy-PTIO, a NO scavenger. Healing of WRS lesions was assessed 0-24 h after termination of WRS. Number of gastric lesions, gastric mucosal blood flow (GBF), malondialdehyde (MDA) content, and RT-PCR expression of HSP70 mRNA were determined. RESULTS: WRS caused typical bleeding erosions that were aggravated by aspirin and this was accompanied by a fall in the GBF and a significant rise in the mucosal MDA concentrations. In contrast, NO-ASA, which raised significantly the luminal content of NO(x), reduced number of WRS lesions and mucosal MDA levels while increasing significantly the GBF. These protective and hyperemic effects of NO-ASA against WRS lesions were mimicked by addition of glyceryl trinitrate to native ASA and significantly attenuated by carboxy-PTIO added to NO-ASA. HSP70 mRNA was significantly upregulated by WRS, and this was significantly attenuated by ASA, but not by NO-ASA. NO-ASA decreased significantly the MDA content and induced overexpression of HSP70 mRNA during healing of WRS lesions. CONCLUSION: NO-ASA exhibits mucosal protective and healing effects against WRS-induced gastric lesions due to the release of NO, which induces gastric hyperemia, and the attenuation of lipid peroxidation and counteracts the inhibition of HSP70 expression induced by native ASA.