Effect of the carbon dioxide 10,600-nm laser and topical fluoride gel application on enamel microstructure and microhardness after acid challenge: an in vitro study.

The aim of this in-vitro study was to evaluate positive effects of the carbon dioxide laser (CO2, 10,600 nm) with acidulated phosphate fluoride (APF) gel on enamel acid resistance. Twenty extracted human third molars (40 surfaces) were randomly assigned into four groups: group C, untreated control; group L, CO2 laser alone group; group F, APF 1.23% fluoride gel; and group FL, APF 1.23% gel and laser. Samples from group L were irradiated with a CO2 laser for 30s. The parameter settings used were average power, 0.73 W; time on, 100 µs; time off, 40 ms; tip-to-tissue distance, 20 mm; tip diameter 700 µm; and energy density with movements, 5 J/cm2. Samples from group F were treated with the APF gel for 4 min, and the gel was washed off with distilled water. The enamel samples from group FL were treated with APF gel for 4 min and then irradiated with the CO2 laser for 30s without removing the gel. Each enamel sample was placed in 50 ml soft drink (pH = 2.75) for 10 min then rinsed with deionized water and stored in artificial saliva at 37 °C for 1 h. Samples were assessed for Vickers hardness number (VHN) before and after treatments and subjected to SEM analysis. Data were analyzed using a one-way analysis of variance (ANOVA) and Tukey's test (α < 0.05). After the acid challenge, the untreated C group was demineralized to a great extent and the enamel surface was with the lowest mean score of microhardness. The observed VHN in the control (C group) had a mean value of 176.13, the scores in the CO2 laser group (L group) were with mean value of 238.40, the F group with a mean value of 218.45, and the fluoride-treated and laser-irradiated FL group-with a mean of 268.28 VHN. Paired t test performed to compare groups C, L, F, and FL has shown that group FL has greater resistance to decrease in microhardness of dental enamel (P ≤ 0.05) on exposure to acidic protocol. After the acid challenge, the fluoride-treated and laser-irradiated samples (group FL) showed the least diminution in enamel surface microhardness. The sub-ablative carbon dioxide laser irradiation in combination with fluoride treatment is more effective in protecting enamel surface and resisting demineralization than CO2 laser irradiation or fluoride alone.

Influence of DL-alpha-tocopherol acetate on indomethacin-induced gastric mucosal injury in rats.

1 There is an increasing body of evidence supporting the hypothesis that antioxidants are able to reduce gastric mucosal damage induced by stressors of different origin. The aim of the present study was to investigate the influence of dl-alpha-tocopherol acetate (TA) on indomethacin-induced gastric mucosal injury in rats and a possible role for an anti-oxidative mechanism in the response. 2 TA (25, 50 and 100 mg kg(-1)) was applied intraperitoneally as a pretreatment 1 h before the subcutaneous administration of indomethacin (30 mg kg(-1)). 3 TA reduced the area of indomethacin-induced gastric ulcers, the effect being significant (P < 0.05) at the highest dose of 100 mg kg(-1). 4 Histopathological examination of rat stomach samples demonstrated that TA caused an increase in gastric mucus production and a reduction of the severity of mucosal lesions. 5 The three doses of TA prevented indomethacin-induced elevation of plasma and mucosal malondialdehyde (MDA) levels, which in TA-pretreated rats were not significantly different from the control values. Neither indomethacin treatment nor TA pretreatment had a significant influence on the gastric mucosal levels of reduced glutathione or oxidized glutathione. 6 Our results suggest that the gastroprotective effect of TA is likely to be due to increased mucus production and interference with oxidative stress development as evidenced by the decreased plasma and gastric mucosal MDA.

Hypoglycemic and hypolipidemic effects of Aronia melanocarpa fruit juice in streptozotocin-induced diabetic rats.

Aronia melanocarpa fruit juice (AMFJ) is rich in phenolic antioxidants, especially flavonoids from the anthocyanin subclass. The aim of the present study was to investigate the influence of AMFJ on plasma glucose and lipids in diabetic rats. Diabetes was induced by an intraperitoneal injection of streptozotocin (50 mg/kg). AMFJ was applied by gavage at doses of 10 and 20 ml/kg for 6 weeks to normal and diabetic rats. Streptozotocin caused a significant elevation of plasma glucose by 141% and of plasma triglycerides (TG) by 64% in comparison with normal control rats and induced statistically insignificant elevations of total cholesterol and LDL-cholesterol and a reduction of HDL-cholesterol. Applied to normal rats, AMFJ did not influence plasma glucose and lipid levels. Applied to diabetic rats, AMFJ (10 and 20 ml/kg) significantly reduced plasma glucose by 44% and 42% and TG by 35% and 39%, respectively, to levels that did not significantly differ from those of the normal control rats and counteracted the influence of streptozotocin on total cholesterol, LDL-cholesterol and HDL-cholesterol. In conclusion, AMFJ significantly decreased the streptozotocin-induced abnormalities in blood glucose and TG in diabetic rats and might be useful in prevention and control of diabetes mellitus and diabetes-associated complications.

Antihyperlipidemic effect of Aronia melanocarpa fruit juice in rats fed a high-cholesterol diet.

Aronia melanocrpa fruit juice (AMFJ) used in our experiment was very rich in phenolic substances (709.3 mg gallic acid equivalents/100 ml juice). Anthocyanins (106.8 mg cyanidin-3-glucoside equivalents/100 ml juice) were the main flavonoid group. The aim of this study was to assess the influence of AMFJ on plasma lipids and lipoprotein profile, and histopathology of liver and aorta in rats with dietary-induced hyperlipidemia. AMFJ was administered by gavage for 30 days at doses of 5, 10 and 20 ml/kg body weight to rats fed a standard diet (SD) or a 4% cholesterol-containing diet (4% ChD). The 4% ChD caused a significant elevation of plasma total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG). AMFJ did not significantly influence plasma lipids in rats fed the SD and significantly hindered the elevation of plasma TC, LDL-C and TG in rats fed the 4% ChD. High-density lipoprotein cholesterol (HDL-C) levels were not significantly influenced either by the 4% ChD or by AMFJ. Neither the cholesterol feeding, nor AMFJ treatment induced any histopathological changes in rat liver and aorta. In conclusion, AMFJ showed an antihyperlipidemic effect in rats with hyperlipidemia and could be valuable in reducing this factor of cardiovascular risk.

Effect of Aronia melanocarpa fruit juice on indomethacin-induced gastric mucosal damage and oxidative stress in rats.

Aronia melanocarpa fruits are rich in phenolic substances-mainly flavonoids from the anthocyanin subclass. The anthocyanins are water-soluble plant pigments with antioxidant, anti-inflammatory, antimicrobial, hepatoprotective, gastroprotective and other activities. We studied the effect of A. melanocarpa fruit juice (AMFJ) on indomethacin-induced gastric mucosal damage in rats and its possible relation to the oxidative status. AMFJ (5, 10 and 20 ml kg(-1)) was applied orally as a pretreatment 1 h before the subcutaneous administration of indomethacin (30 mg kg(-1)). Gastric ulcer formation was estimated morphometrically and histopathologically 4h after the indomethacin administration. Malondialdehyde (MDA) in rat plasma and gastric mucosa and also reduced glutathione (GSH) and oxidized glutathione (GSSG) in gastric mucosa were determined and used as biochemical markers of the oxidative status. AMFJ-pretreatment diminished the number and area of indomethacin-induced gastric lesions. Histopathological examination of rat stomachs demonstrated that AMFJ induced an increase in gastric mucus production and a reduction of the depth and severity of indomethacin-induced mucosal lesions. AMFJ dose-dependently reduced the elevated indomethacin plasma and gastric MDA levels and at the doses of 10 and 20 ml kg(-1) they were not significantly different from the control values. Neither indomethacin-treatment, nor AMFJ-pretreatment had a significant influence on GSH and GSSG gastric mucosal levels. These results demonstrated that indomethacin-induced gastric mucosal damage was accompanied by the development of oxidative stress, evidenced by the accumulation of MDA. AMFJ-pretreatment decreased the gastric lesions caused by indomethacin. It could be suggested that this effect of AMFJ was probably due to the increased mucus production and interference with oxidative stress development as evidenced by the decreased plasma and gastric mucosal MDA.

Overexpression of neuropilin-1 promotes constitutive MAPK signalling and chemoresistance in pancreatic cancer cells.

Neuropilin-1 (NRP-1) is a novel co-receptor for vascular endothelial growth factor (VEGF). Neuropilin-1 is expressed in pancreatic cancer, but not in nonmalignant pancreatic tissue. We hypothesised that NRP-1 expression by pancreatic cancer cells contributes to the malignant phenotype. To determine the role of NRP-1 in pancreatic cancer, NRP-1 was stably transfected into the human pancreatic cancer cell line FG. Signal transduction was assessed by Western blot analysis. Susceptibility to anoikis (detachment induced apoptosis) was evaluated by colony formation after growth in suspension. Chemosensitivity to gemcitabine or 5-fluorouracil (5-FU) was assessed by MTT assay in pancreatic cancer cells following NRP-1 overexpression or siRNA-induced downregulation of NRP-1. Differential expression of apoptosis-related genes was determined by gene array and further evaluated by Western blot analysis. Neuropilin-1 overexpression increased constitutive mitogen activated protein kinase (MAPK) signalling, possibly via an autocrine loop. Neuropilin-1 overexpression in FG cells enhanced anoikis resistance and increased survival of cells by > 30% after exposure to clinically relevant levels of gemcitabine and 5-FU. In contrast, downregulation of NRP-1 expression in Panc-1 cells markedly increased chemosensitivity, inducing > 50% more cell death at clinically relevant concentrations of gemcitabine. Neuropilin-1 overexpression also increased expression of the antiapoptotic regulator, MCL-1. Neuropilin-1 overexpression in pancreatic cancer cell lines is associated with (a) increased constitutive MAPK signalling, (b) inhibition of anoikis, and (c) chemoresistance. Targeting NRP-1 in pancreatic cancer cells may downregulate survival signalling pathways and increase sensitivity to chemotherapy.

Hepatoprotective effect of the natural fruit juice from Aronia melanocarpa on carbon tetrachloride-induced acute liver damage in rats.

The fruits of Aronia melanocarpa are rich in anthocyanins--plant pigments with anti-inflammatory and antioxidant activity. We studied the effect of the natural fruit juice from A. melanocarpa (NFJAM) on carbon tetrachloride (CCl4)-induced acute liver damage in rats. Histopathological changes such as necrosis, fatty change, ballooning degeneration and inflammatory infiltration of lymphocytes around the central veins occurred in rats following acute exposure to CCl4 (0.2 ml kg(-1), 2 days). The administration of CCl4 increased plasma aspartate transaminase (AST) and alanine transaminase (ALT) activities, induced lipid peroxidation (as measured by malondialdehyde (MDA) content in rat liver and plasma) and caused a depletion of liver reduced glutathione (GSH). NFJAM (5, 10 and 20 ml kg(-1), 4 days) dose-dependently reduced the necrotic changes in rat liver and inhibited the increase of plasma AST and ALT activities, induced by CCl4 (0.2ml kg(-1), 3rd and 4th days). NFJAM also prevented the CCl4-induced elevation of MDA formation and depletion of GSH content in rat liver.

Esthetic restoration of traumatized permanent teeth in children using composite vestibular veneers (preliminary communication).

UNLABELLED: All people are eager to have attractive dental looks. Esthetic corrections of defects caused by colour alteration are required more and more frequently by dental patients. Very often even the form of viable or devitalised teeth in children is wanted to be changed. The modern composite materials allow this to be done by vestibular veneers satisfying even the highest requirements in this respect. THE AIM of the study was to address the matter of the restoration of traumatised permanent children's teeth by composite veneers. MATERIALS AND METHODS: The study included 30 traumatized permanent anterior teeth in children which, after dealing with the trauma, were restored by means of composite veneers. The teeth were first prepared using a suitable method and the composite veneers were fabricated during the same visit. The patients were evaluated at one, three and six months. RESULTS: The colour, margin integrity, surface structure, and anatomic form were rated using the California Dental Association's criteria. CONCLUSIONS. Restoration of traumatized permanent teeth in children with vestibular veneers yields very good clinical results. The composite veneers is an alternative method in restoration of such teeth in children.

A study on fear provoking factors in students from the town of Plovdiv.

UNLABELLED: The self-report measure of fear of children dental patients is an important point in screening and determining strategies of behaviour's management. AIM: The aim of this investigation was to assess dental fear in students from the town of Plovdiv, aged 12, 13 and 14, by using Dental Fear Survey Schedule for Children (DFSS-DS) and to determine the causes. MATERIAL AND METHODS: The study included 312 students (161 girls and 151 boys) aged 12, 13 and 14, residents of Plovdiv. They completed the Children Fear Survey Schedule - Dental Subscale. 15 personalities, objects and circumstances have been given estimation points varying from 1 to 5. RESULTS: The results showed that the average level of fear reported amounted to 32.04 +/- 9.8 in girls and to 22.56 +/- 7.6 in boys. Fear of choking is the most frequently reported fear, fear of dentist drilling machines comes next. CONCLUSIONS: Most of the students at the ages of 12, 13 and 14 report quite a fear respect to dental treatment. As a result their oral health gets worse and requires working out of strategies to overcome fear.

Long-term effects of portacaval anastomosis on the 5-hydroxytryptamine, histamine, and catecholamine neurotransmitter systems in rat brain.

Portacaval anastomosis (PCA) in the rat is used as a model for portal systemic encephalopathy. Changes in the serotonergic, histaminergic, and catecholaminergic neurotransmitter systems are often found shortly after PCA. We have examined the long-term effects of PCA on the aminergic systems in brains of male Wistar rats, which 8 months previously had been subjected to PCA. Precursors, amines, and metabolites were assayed by HPLC. Eight months after PCA, the catecholamine levels were unchanged in all brain regions. In contrast, tryptophan was evenly increased throughout the brain. The accumulation of 5-hydroxytryptophan after decarboxylase inhibition (NSD-1015; 100 mg/kg i.p.) and the endogenous levels of 5-hydroxyindoleacetic acid were significantly higher in PCA rats, particularly in the hypothalamus and midbrain, whereas 5-hydroxytryptamine concentrations were unchanged. Histamine levels were elevated throughout the brain with the greatest increase found in the hypothalamus and in the striatum. tele-Methylhistamine levels were significantly elevated in cortex and hypothalamus. We conclude that 8 months after PCA, catecholaminergic systems had reestablished their homeostasis, whereas serotonergic and histaminergic systems still show profound disturbances in their function. With histamine, this is reflected as an increase in the amounts of both transmitter and metabolite; serotonergic neurons respond by increasing only the level of the metabolite.

Antispasmogenic and spasmolytic effects of verapamil and salbutamol, alone and in combination, on histamine-induced guinea pig tracheal contraction in vitro.

The antispasmogenic and spasmolytic effects of the calcium entry blocker verapamil were examined on histamine-induced guinea pig tracheal contraction in vitro in comparison with the beta 2-adrenergic agonist salbutamol. The effects of verapamil were found to be about 1000 times weaker than those of salbutamol. The antispasmogenic IC50 for verapamil was 1.99 x 10(-4) M compared to 7.94 x 10(-8) M for salbutamol. The spasmolytic EC50 for verapamil was 3.37 x 10(-5) M and for salbutamol was 1.95 x 10(-8) M. The combined application of verapamil and salbutamol resulted in additive antispasmogenic and spasmolytic effects.

Gastric histamine content and ulcer formation in rats with ethanol-induced injury. Effects of cinnarizine and flunarizine.

The effects of the calcium antagonists cinnarizine and flunarizine on gastric histamine content and ulcer formation in rats with ethanol-induced injury were studied. Gastric ulcers were inflicted by oral application of 50% or 100% ethanol solution. Cinnarizine (20 mg/kg), flunarizine (10 mg/kg) and cimetidine (100 mg/kg) were administered orally 1 h before ethanol. Histamine was assayed fluorometrically. No effect of the tested drugs on 50% ethanol-induced gastric damage was observed. Cinnarizine and flunarizine inhibited 100% ethanol-induced lesion formation by 71% (p < 0.01) and 20% (p > 0.05), respectively. The inhibition exerted by cimetidine was 54% (p < 0.05). Gastric histamine content was not affected by 50% ethanol, while 100% ethanol decreased it two-fold. None of the tested drugs induced significant changes in gastric histamine levels. No correlation was obtained between the ulceroprotective effect of the used calcium antagonists and the gastric histamine content in ethanol-induced injury.

Antiinflammatory effect of flavonoids in the natural juice from Aronia melanocarpa, rutin and rutin-magnesium complex on an experimental model of inflammation induced by histamine and serotonin.

The antiinflammatory effects of the anthocyane flavonoids in the natural juice from Aronia melanocarpa and of rutin-magnesium complex, the water-soluble derivative of rutin were studied in comparison with rutin. Two experimental models of inflammation were used. Inflammation of rat hind paw was induced either by 0.5% solution of histamine or by 0.01% solution of serotonin. The swelling of the rat paw was measured oncometrically by a pletismometer. The results showed that the anthocyane flavonoids from the natural juice of Aronia melanocarpa exerted more pronounced effects as compared to rutin in both models of inflammation. The rutin-magnesium complex did not exhibit any antiinflammatory activity against histamine-induced inflammation. Its effects against serotonin-induced inflammation were comparable to those of rutin.