Influence of Nd:YAG laser on intrapulpal temperature and bond strength of human dentin under simulated pulpal pressure.

The aim of this study was to evaluate the effects of simulated pulpal pressure (SPP) on the variation of intrapulpal temperature (ΔT) and microtensile bond strength (µTBS) to dentin submitted to an adhesive technique using laser irradiation. One hundred sound human molars were randomly divided into two groups (n = 50), according to the presence or absence of SPP (15 cm H2O). Each group was divided into five subgroups (n = 10) according to Nd:YAG laser energy (60, 80, 100, 120, 140 mJ/pulse). The samples were sequentially treated with the following: 37 % phosphoric acid, adhesive (Scotchbond Universal), irradiation with Nd:YAG laser (60 s), and light curing (10 s). ΔT was evaluated during laser irradiation using a type K thermocouple. Next, a composite resin block was build up onto the irradiated area. After 48 h, samples were submitted to microtensile test (10 kgf load cell, 0.5 mm/min). Data were analyzed by two-way ANOVA and Tukey tests (p = 0.05). ANOVA revealed significant differences for ΔT and TBS in the presence of SPP. For ΔT, the highest mean (14.3 ± 3.23 °C)(A) was observed in 140 mJ and without SPP. For µTBS, the highest mean (33.4 ± 4.15 MPa)(A) was observed in 140 mJ and without SPP. SPP significantly reduced both ΔT and µTBS during adhesive procedures, lower laser energy parameters resulted in smaller ΔT, and the laser parameters did not influence the µTBS values.

Effect of a selective nonsteroidal anti-inflammatory inhibitor of cyclooxygenase-2 on the small bowel of rats.

The pathogenesis of nonsteroidal anti-inflammatory drug (NSAID) enteropathy is a complex process involving the uncoupling of mitochondrial oxidative phosphorylation and inhibition of cyclooxygenase (COX). Rofecoxib, a selective inhibitor of COX-2, has shown less gastric damage, but the same beneficial effect is not clear in the case of the small bowel. Fifty-seven male Wistar rats (250-350 g) were divided into three groups (N=19 each) to evaluate the effect of this NSAID on the rat intestine. The groups received 2.5 mg/kg rofecoxib, 7.5 mg/kg indomethacin or water with 5% DMSO (control) given as a single dose by gavage 24 h before the beginning of the experiment. A macroscopic score was used to quantify intestinal lesions and intestinal permeability was measured using [51Cr]-ethylenediaminetetraacetic acid ([51Cr]-EDTA). The extent of intestinal lesion, indicated by a macroscopic score, was significantly lower when rofecoxib was administered compared to indomethacin (rofecoxib=0.0 vs indomethacin=63.6 +/- 25.9; P<0.05) and did not differ from control. The intestinal permeability to [51Cr]-EDTA was significantly increased after indomethacin (control=1.82 +/- 0.4 vs indomethacin=9.12 +/- 0.8%; P<0.0001), but not after rofecoxib, whose effect did not differ significantly from control (control=1.82 +/- 0.4 vs rofecoxib=2.17 +/- 0.4%; ns), but was significantly different from indomethacin (indomethacin=9.12 +/- 0.8 vs rofecoxib=2.17 +/- 0.4%; P<0.001). In conclusion, the present data show that rofecoxib is safer than indomethacin in rats because it does not induce macroscopic intestinal damage or increased intestinal permeability.

Effect of a selective nonsteroidal anti-inflammatory inhibitor of cyclooxygenase-2 on the small bowel of rats

The pathogenesis of nonsteroidal anti-inflammatory drug (NSAID) enteropathy is a complex process involving the uncoupling of mitochondrial oxidative phosphorylation and inhibition of cyclooxygenase (COX). Rofecoxib, a selective inhibitor of COX-2, has shown less gastric damage, but the same beneficial effect is not clear in the case of the small bowel. Fifty-seven male Wistar rats (250-350 g) were divided into three groups (N = 19 each) to evaluate the effect of this NSAID on the rat intestine. The groups received 2.5 mg/kg rofecoxib, 7.5 mg/kg indomethacin or water with 5 percent DMSO (control) given as a single dose by gavage 24 h before the beginning of the experiment. A macroscopic score was used to quantify intestinal lesions and intestinal permeability was measured using [51Cr]-ethylenediaminetetraacetic acid ([51Cr]-EDTA). The extent of intestinal lesion, indicated by a macroscopic score, was significantly lower when rofecoxib was administered compared to indomethacin (rofecoxib = 0.0 vs indomethacin = 63.6 ± 25.9; P < 0.05) and did not differ from control. The intestinal permeability to [51Cr]-EDTA was significantly increased after indomethacin (control = 1.82 ± 0.4 vs indomethacin = 9.12 ± 0.8 percent; P < 0.0001), but not after rofecoxib, whose effect did not differ significantly from control (control = 1.82 ± 0.4 vs rofecoxib = 2.17 ± 0.4 percent; ns), but was significantly different from indomethacin (indomethacin = 9.12 ± 0.8 vs rofecoxib = 2.17 ± 0.4 percent; P < 0.001). In conclusion, the present data show that rofecoxib is safer than indomethacin in rats because it does not induce macroscopic intestinal damage or increased intestinal permeability.

Intestinal permeability in strongyloidiasis.

The objective of the present study was to assess intestinal permeability in patients with infection caused by Strongyloides stercoralis. Twenty-six patients (16 women and 10 men), mean age 45.9, with a diagnosis of strongyloidiasis were evaluated. For comparison, 25 healthy volunteers (18 women and 7 men), mean age 44.9, without digestive disorders or intestinal parasites served as normal controls. Intestinal permeability was measured on the basis of urinary radioactivity levels during the 24 h following oral administration of chromium-labeled ethylenediaminetetraacetic acid ((51)Cr-EDTA) expressed as percentage of the ingested dose. The urinary excretion of (51)Cr-EDTA was significantly reduced in patients with strongyloidiasis compared to controls (1.60 +/- 0.74 and 3.10 +/- 1.40, respectively, P = 0.0001). Intestinal permeability is diminished in strongyloidiasis. Abnormalities in mucus secretion and intestinal motility and loss of macromolecules could explain the impaired intestinal permeability.

Intestinal permeability in strongyloidiasis

The objective of the present study was to assess intestinal permeability in patients with infection caused by Strongyloides stercoralis. Twenty-six patients (16 women and 10 men), mean age 45.9, with a diagnosis of strongyloidiasis were evaluated. For comparison, 25 healthy volunteers (18 women and 7 men), mean age 44.9, without digestive disorders or intestinal parasites served as normal controls. Intestinal permeability was measured on the basis of urinary radioactivity levels during the 24 h following oral administration of chromium-labeled ethylenediaminetetraacetic acid (51Cr-EDTA) expressed as percentage of the ingested dose. The urinary excretion of 51Cr-EDTA was significantly reduced in patients with strongyloidiasis compared to controls (1.60 + or - 0.74 and 3.10 + or - 1.40, respectively, P = 0.0001). Intestinal permeability is diminished in strongyloidiasis. Abnormalities in mucus secretion and intestinal motility and loss of macromolecules could explain the impaired intestinal permeability

Protective effect of metronidazole on uncoupling mitochondrial oxidative phosphorylation induced by NSAID: a new mechanism.

BACKGROUND: The pathogenesis of non-steroidal anti-inflammatory drug (NSAID) enteropathy is complex. It involves uncoupling of mitochondrial oxidative phosphorylation which alters the intercellular junction and increases intestinal permeability with consequent intestinal damage. Metronidazole diminishes the inflammation induced by indomethacin but the mechanisms remain speculative. A direct effect on luminal bacteria has traditionally been thought to account for the protective effect of metronidazole. However, a protective effect of metronidazole on mitochondrial oxidative phosphorylation has never been tested. AIMS: To assess the protective effect of metronidazole on mitochondrial uncoupling induced by indomethacin and also on the increased intestinal permeability and macroscopic damage. MATERIAL AND METHODS: The protective effect of metronidazole was evaluated in rats given indomethacin; a macroscopic score was devised to quantify intestinal lesions, and intestinal permeability was measured by means of (51)Cr-ethylenediaminetetraacetic acid. The protective effect of metronidazole against mitochondrial uncoupling induced by indomethacin was assessed using isolated coupled rat liver mitochondria obtained from rats pretreated with metronidazole or saline. RESULTS: Metronidazole significantly reduced the macroscopic intestinal damage and increase in intestinal permeability induced by indomethacin; furthermore, at the mitochondrial level, it significantly reduced the increase in oxygen consumption in state 4 induced by indomethacin and caused less reduction of the respiratory control rate. CONCLUSION: Our study confirmed the beneficial effects of metronidazole on intestinal damage and intestinal permeability, and demonstrated, for the first time, a direct protective effect of metronidazole on uncoupling of mitochondrial oxidative phosphorylation caused by NSAIDs.

Dentin bond strength: influence of laser irradiation, acid etching, and hypermineralization.

OBJECTIVE: The purpose of the present study was to investigate the effects of ND:YLF laser irradiation (1.31 J/cm2; 250 mJ per pulse), acid etching, and hypermineralization on the shear bond strength (SBS) of the Scotchbond Multi-Purpose Plus (3M Dental Products) bonding system. SUMMARY BACKGROUND DATA: Previous studies had shown that the pretreatment of the dentin substrate with laser irradiation can influence the SBS. METHODS: Sixty bovine incisors were selected and stored at -18 degrees C. Dentinal buccal surface was exposed and radiographs were taken to control dentin thickness. The specimens were separated into 2 groups: (1) the control, which was kept in distilled water at 4 degrees C; (2) the hypermineralized, which was kept in hypermineralizing solution at 4 degrees C for 14 days. Each group was divided into 3 subgroups according to the type of dentin pretreatment used: M (acid etching + primer + bond); AL (acid etching + primer + bond + laser); and LA (laser + acid etching + primer + bond). A standard composite resin cylinder (Z100-3M) was bonded to the dentinal surface and the SBS performed on an Instron machine (500 Kg load cell at 0.5 mm/min), followed by scanning electron microscopy (SEM) and x-ray diffraction analysis. RESULTS: Analysis of variance (ANOVA) determined that the pretreatments influenced the SBS values (p < 0.05): AL (9.96 MPa), M (7.28 MPa), and LA (4.87 MPa). The interaction between the group and pretreatment factors also influenced the SBS (p < 0.05). The highest values were obtained for the interaction control/AL (11.64 MPa). CONCLUSION: The results suggested that dentin treatment with laser after the application of the adhesive system is efficient in achieving higher bond strength and is promising as a possible new adhesive substrate.

Differential expression of interleukin 1 receptor antagonist isoforms in human intestinal epithelial cells.

BACKGROUND & AIMS: Regulatory cytokines mediate intestinal epithelial cell (IEC) participation in mucosal immune responses. The aim of this study was to investigate the expression of secretory and intracellular isoforms of interleukin 1 receptor antagonist (IL-1Ra) in human primary IECs and carcinoma-derived cell lines. METHODS: Primary IECs were isolated from patients with Crohn's disease or ulcerative colitis and from normal controls. Isoform-specific IL-1Ra messenger RNA (mRNA) and protein were assessed by reverse-transcription polymerase chain reaction and Western blot analysis. Expression during cellular differentiation was determined by in situ immunohistochemistry on sequentially released, native IECs and in vitro differentiated cell lines. Intracellular IL-1Ra I function was analyzed by permanent transfection of Caco-2 cells. RESULTS: Intracellular IL-1Ra I protein accumulated in surface IECs with extension to the crypts during inflammation. Secretory IL-1Ra and intracellular IL-1Ra II mRNA, but not the corresponding protein, was detected. Transcription of intracellular IL-1Ra I mRNA was significantly up-regulated with inflammation and in vitro by phorbol myristate acetate and interleukin 1beta. In vitro differentiated cells had higher constitutive intracellular IL-1Ra I protein content. Intracellular IL-1Ra I expression in Caco-2 cells decreased IL-1beta-stimulated interleukin 8 secretion. CONCLUSIONS: Native human IECs and certain cell lines constitutively express intracellular IL-1Ra type I, which is up-regulated by inflammation, inflammatory stimuli, and cellular differentiation. Constitutive expression of this anti-inflammatory cytokine may contribute to mucosal protection.

Effects of colectomy on gallbladder motility in patients with ulcerative colitis.

In order to gain insight into the possible mechanisms involved in gallstone formation in colectomized ulcerative colitis patients, we studied gallbladder motility by means of ultrasonography in three groups of subjects: controls (N = 40) and ulcerative colitis patients without (N = 30) and with (N = 20) colectomy. Impaired gallbladder emptying after a liquid fatty meal stimulus was observed in ulcerative colitis patients with colectomy compared with those obtained in ulcerative colitis patients without colectomy and controls (P = 0.001). The maximum percentage of gallbladder emptying also, was significantly lower (59.8%) than those seen in ulcerative colitis patients without colectomy (74.5%) and controls (77.8%) (P = 0.001). Diminished gallbladder emptying with ensuing stasis might be a contributory factor to the increased prevalence of gallstones in colectomized patients.

Gallbladder hypokinesia in Crohn's disease.

For the purpose of shedding some light upon the possible mechanisms involved in gallstone formation in patients with Crohn's disease, we have investigated gallbladder emptying by means of ultrasonography in two groups of subjects: controls (n = 40) and Crohn's disease (n = 30). Diminished gallbladder emptying after a liquid fatty-meal stimulus was observed in patients with Crohn's disease when compared with controls (p < 0.001). Also, the values for the residual gallbladder volume (RGV) and maximal decrease in gallbladder volume (MDGV), both in milliliters and percentage were, respectively, increased (RGV = 9.6 ml) and diminished (MDGV = 14.8 ml; MDGV = 60.9%) in patients with Crohn's disease when compared with controls (RGV = 5.9 ml, p < 0.001; MDGV = 19.9 ml, p = 0.003; MDGV = 77.8%, p < 0.001). Hence, reduced gallbladder emptying with consequent stasis might be a contributory factor to the increased prevalence of gallstones in Crohn's disease.

Reproducibility of the ultrasound method for measurement of gallbladder volume.

Gallbladder motility has largely been studied in recent years. Since the ultrasonographic method can be used in gallbladder emptying studies, we investigated the reproducibility of the ultrasound method for measurement of gallbladder volume. The ultrasonographic method was highly reproducible (r = 0.97) and, due to its safeness and lack of use of radioactive agents, it is attractive option for gallbladder motility studies in conditions associated with increased frequency of cholelithiasis.

Measurement of gastric emptying time by real-time ultrasonography in patients with Crohn's disease.

In order to gain some insight into the possible influence of gastric emptying on gallbladder hypomotility in patients with Crohn's disease, the gastric emptying time (GET) was measured by means of ultrasonography in 10 healthy controls and 10 patients with Crohn's disease. No significant difference was observed between both mean values for GET studies (GET: controls, 165.0 min +/- 12.8; Crohn, 142.0 min +/- 11.5; p = 0.208) after ingestion of a liquid meal. Thus, the gallbladder hypomotility described in patients with Crohn's disease, after a liquid fatty-meal stimulus, can not be explained by prolonged gastric emptying time.

[Assessment of arterial occlusive disease with Duplex sonography. Prospective study]. / Avaliação da doença oclusiva das artérias renais com Triplex Scan. Estudo prospectivo.

Occlusive disease involving the renal arteries represent a major cause of curable hypertension and improvement of renal dysfunction. Angiography is still the major diagnostic procedure. Isotopic methods with Captopril and split-function studies have shown high incidence of false-positive and false-negative results. Colour flow Duplex-Scan renders possible the visualization of the aorta and renal arteries, is noninvasive and combines morphologic and hemodynamic evaluation. To assess its efficacy in the diagnosis of renal artery occlusive disease, a prospective blind study was undertaken in 24 patients, 48 renal arteries, 15 women and 9 men, with mean age of 44 years. Scans of the aorta and renal arteries at the origin, along its extension and at the renal hilum were obtained using and ATL Ultrmark 9 with 3.0 MHZ probe Velocity measurements were obtained at the aorta and along the renal arteries. Criteria for a positive examination were: focal acceleration with a reduction of the flow velocity at the hilum. Absence of flow in a properly visualized renal artery was considered as occlusion. All patients had digital subtraction arteriography. In 1 patient the non-invasive examination was inadequate. In the remain 23 patients the exam was considered adequate. False-positives were 4.8%; false-negatives 8.7%. Sensitivity, specificity and accuracy were respectively 91.7%, and 95.7% and 93.5%. These results suggest that non-invasive assessment of renal artery occlusive disease is feasible and accurate when compared to angiography, thus providing a useful tool for screening hypertensive patients.

Chylomicron metabolism in experimental cirrhosis and cholestasis.

Recently it has been demonstrated that artificial emulsions made of lecithin, cholesterol, cholesteryl-oleate and triolein simulate the metabolism of the natural chylomicra. Artificial-chylomicron delipidation and remnant disappearance from plasma were investigated in rats with carbon tetrachloride-induced hepatic cirrhosis or with cholestasis due to bile-duct ligation. Artificial chylomicra were labelled simultaneously with glyceryl tri [9, 10 (N)-3H] oleate and cholesteryl [1-14C] oleate and injected intra-arterially. Simultaneous chylomicron delipidation and remnant removal by the liver were calculated from the plasma radioactivity decay curves: that of glyceryl tri [9, 10 (N)-3H] oleate signifying the combined delipidation and particle-removal processes, whereas that of cholesteryl [1-14C] oleate representing the particle disappearance rate from plasma. Particle delipidation was increased in cirrhosis and decreased in cholestasis, implying faster and slower lipolysis rates respectively. On the other hand, the remnant removal rate by the liver slowed down in both experimental pathologies.

Optical and crystalline properties of PbF(2) thin films.

The optical and crystalline properties of PbF(2) thin films as a function of the substrate temperature during deposition have been studied; the other evaporation conditions were kept as constant as possible. Channel spectra, guided modes, and ellipsometry techniques were used for the analysis of the optical properties of the films. X-ray diffraction was used for the analysis of the crystalline structure.