Erosive cola-based drinks affect the bonding to enamel surface: an in vitro study

Objective

This study aimed to assess the impact of in vitro erosion provoked by different cola-based drinks (Coke types), associated or not with toothbrushing, to bonding to enamel.

Material and Methods

Fifty-six bovine enamel specimens were prepared and randomly assigned into seven groups (N=8): C- Control (neither eroded nor abraded), ERO-RC: 3x/1-minute immersion in Regular Coke (RC), ERO-LC: 3x/1-minute immersion in Light Coke (LC), ERO-ZC: 3x/1-minute immersion in Zero Coke (ZC) and three other eroded groups, subsequently abraded for 1-minute toothbrushing (EROAB-RC, EROAB-LC and EROAB-ZC, respectively). After challenges, they were stored overnight in artificial saliva for a total of 24 hours and restored with Adper Single Bond 2/Filtek Z350. Buildup coronal surfaces were cut in 1 mm² -specimens and subjected to a microtensile test. Data were statistically analyzed by two-way ANOVA/Bonferroni tests (α=0.05). Failure modes were assessed by optical microscopy (X40). The interface of the restorations were observed using Confocal Laser Scanning Microscopy (CLSM).

Results

All tested cola-based drinks significantly reduced the bond strength, which was also observed in the analyses of interfaces. Toothbrushing did not have any impact on the bond strength. CLSM showed that except for Zero Coke, all eroded specimens resulted in irregular hybrid layer formation.

Conclusions

All cola-based drinks reduced the bond strength. Different patterns of hybrid layers were obtained revealing their impact, except for ZC.     

Biochemical study and in vitro insect immune suppression by a trypsin‐like secreted protease from the nematode Steinernema carpocapsae

A trypsin‐like serine protease was purified by gel filtration and anion‐exchange chromatography from the excretory‐secretory products of parasitic phase Steinernema carpocapsae. The purified protease exhibited a molecular mass of about 29 kDa by SDS–PAGE and displayed a pI of 6·3. This protease exhibited high activity with trypsin‐specific substrate N‐Ben‐Phe‐Val‐Arg‐p‐nitroanilide and was highly sensitive to aprotinin and benzamidine. The purified trypsin protease digested the chromogenic substrate N‐Ben‐Phe‐Val‐Arg‐p‐nitroanilide with K_m, V_max and k_cat values of 594·2 μm , 0·496 μm /min and 22·8/s, respectively. The optimal pH and temperature for protease activity were 9 and 30°C, respectively. Internal amino acid sequencing yielded 150 amino acids and these were homologous to other trypsin sequences. In vitro investigation was carried out to monitor prophenoloxidase suppression in Galleria mellonella by the purified protease; about 38·9–52·6% suppression of prophenoloxidase was observed. The purified protease affected insect haemocyte spreading, causing cells to become spherical or round. Protease‐treated actin filaments were highly disorganized in haemocytes. In vitro, G. mellonella haemocytes recognized infective juveniles of Heterorhabditis bacteriophora; however, S. carpocapsae and Steinernema glaseri were not recognized. We provide experimental evidence that the purified trypsin has the potential to alter host haemocytes, actin filaments and to inhibit host haemolymph melanization.     

Perturbation of phospholipid and triacylglycerol fatty acid positional location in the heart of rats depleted of n-3 long-chain polyunsaturates

Rats depleted of long-chain polyunsaturated n-3 fatty acids (n-3–D) display several features of the metabolic syndrome, including obesity, liver steatosis, insulin resistance, hypertension, and cardiac hypertrophy. In this study, the heart phospholipid (PL) and triacylglycerol (TG) fatty acid content and pattern were compared between female control rats (C) and n-3–D rats. The sole n-3 fatty acids found in n-3–D rats, C22:5(n-3) and C22:6(n-3), were 10 to 20 times lower than in C. The total fatty acid content of PL was lower in n-3–D rats than C. No ectopic TG accumulation was found in n-3–D rats. In both PL and TG, the C16:0/C16:1(n-7) and C18:0/C18:1(n-9) ratios suggested increased Δ9-desaturase activity in n-3–D rats. The PL C18:2(n-6)/C20:4(n-6) and C20:4(n-6)/C22:4(n-6) ratios were also lower in n-3–D rats than C. Prior intravenous injection of a medium-chain TG:fish oil emulsion to n-3–D rats 60 to 120 minutes before killing augmented the PL content in C22:5(n-3) and C22:6(n-3), minimized the age-related decrease in the PL C18:1(n-9) relative content, and increased the TG C22:4(n-6) content. The alteration of cardiac function in n-3–D rats and its improvement after injection of medium-chain TG:fish oil emulsion coincides with parallel changes in heart lipid fatty acid content and pattern.     

Myocardial perfusion imaging with technetium-99m sestamibi SPECT in the evaluation of coronary artery disease

Technetium-99m hexakis-2-methoxy-isobutyl-isonitrile(^99mTc sestamibi) has been used for myocardial perfusion imaging in the evaluation of coronary artery disease (CAD) since 1990. The experience of its use in an Asian population with and without previous myocardial infarction (Ml), diabetes mellitus (DM), hypertension (HPT) and collateral circulation (COL) is reported. One hundred and thirty-nine patients who underwent treadmill exercise testing with ^99mTc sestamibi single photon emission computed tomography (SPECT) and coronary angiogram were studied. The overall sensitivity for the detection of CAD was 91.0% and specificity was 64.7%. For patients without previous myocardial infarction, the sensitivity was 83.8% and specificity was 83.3%. Patients with COL had a higher sensitivity while those with HPT had a lower specificity. Sensitivity was higher in patients with multi-vessel disease (MVD) than single vessel disease (SVD). The overall detection for individual artery stenosis was 74.1% with a specificity of 73.1 %. Amongst the three major coronary arteries, sensitivity was highest for the right coronary artery and specificity was highest for the left circumflex artery. Specificity was higher in patients without MI or COL. We found that the agreement between ^99mTc sestamibi SPECT and coronary angiogram for the extent of CAD was only 52.5%. The concordance rate was higher for patients with MVD than SVD. It is concluded that ^99mTc sestamibi SPECT is a sensitive and specific test for the detection of CAD and localization of disease to individual coronary arteries in our patients with some differences in the subgroups. Agreement between coronary angiogram and ^99mTc sestamibi for the extent of coronary artery disease was also satisfactory.     

Chronic hydroxymethylglutaryl coenzyme a reductase inhibition and endothelial function of the normocholesterolemic rat: comparison with angiotensin-converting enzyme inhibition

The purpose of the current study was to evaluate nifedipine-induced epicardial and microvascular response in human coronary arteries with and without endothelial dysfunction and intimal thickening. The investigation was performed in 70 patients 5 +/- 5 months after heart transplantation. Coronary vasomotor function was determined with intracoronary acetylcholine adenosine, and nifedipine, respectively. Intravascular ultrasound was used to detect significant intimal hyperplasia. In a subgroup (n = 38), coronary sinus and aortic endothelin concentrations were determined. Epicardial dilation to nifedipine was significantly enhanced in coronary arteries with endothelial dysfunction (p = 0.04), whereas adenosine-induced epicardial dilation was attenuated in segments with endothelial dysfunction (p = 0.002). In cases of intimal hyperplasia, nifedipine-mediated distal vasodilation was increased compared with normal segments (p = 0.03). Coronary flow index nifedipine was enhanced in patients with microvascular endothelial dysfunction (p = 0.037). A trend was observed between high endothelin plasma levels in the coronary sinus and an increased microvasodilation to nifedipine (p = 0.04). The study shows that epicardial and microvascular dilation to nifedipine is enhanced in the setting of coronary endothelial dysfunction, suggesting supersensitive dilator response. The association between microvascular response to nifedipine and endothelin levels in the coronary sinus needs further clarification.     

P-cresol,a uremic toxin,decreases endothelial cell response to inflammatory cytokines

BACKGROUND: Infectious diseases are among the most morbid events in uremia. The uremic toxin p-cresol may play a role in the immunodeficiency of uremia by depressing phagocyte functional capacity. Leukocyte adhesion to endothelium, a key event in the immune response, is mediated by endothelial adhesion molecules. These include intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin, which are induced by various inflammatory cytokines. We asked whether p-cresol alters endothelial adhesion molecule expression and modifies endothelial/leukocyte adhesion. METHODS: Human umbilical vein endothelial cells (HUVEC) were incubated with p-cresol in the presence or absence of tumor necrosis factor (TNF) or interleukin-1beta (IL-1beta). Thereafter, the endothelial molecules ICAM-1, VCAM-1, and E-selectin were quantitated and the monocyte (THP-1) adhesion to HUVEC measured. RESULTS: P-cresol decreased cytokine-induced protein and mRNA expression of ICAM-1 and VCAM-1. In addition, p-cresol significantly decreased the adhesion of THP-1 to cytokine-stimulated HUVEC. CONCLUSIONS: P-cresol may play a role in the immune defect of uremic patients by inhibiting cytokine-induced endothelial adhesion molecule expression and endothelium/monocyte adhesion.     

Mechanisms of desflurane-induced preconditioning in isolated human right atria in vitro

BACKGROUND: The authors examined the role of adenosine triphosphate-sensitive potassium (K(ATP)) channels, adenosine A1 receptor, and alpha and beta adrenoceptors in desflurane-induced preconditioning in human myocardium, in vitro. METHODS: The authors recorded isometric contraction of human right atrial trabeculae suspended in oxygenated Tyrode's solution (34 degrees C; stimulation frequency, 1 Hz). Before a 30-min anoxic period, 3, 6, and 9% desflurane was administered during 15 min. Desflurane, 6%, was also administered in the presence of 10 microm glibenclamide, a K(ATP) channels antagonist; 10 microm HMR 1098, a sarcolemmal K(ATP) channel antagonist; 800 microm 5-hydroxy-decanoate (5-HD), a mitochondrial K(ATP) channel antagonist; 1 microm phentolamine, an alpha-adrenoceptor antagonist; 1 microm propranolol, a beta-adrenoceptor antagonist; and 100 nm 8-cyclopentyl-1,3-dipropylxanthine (DPX), the adenosine A1 receptor antagonist. Developed force at the end of a 60-min reoxygenation period was compared (mean +/- SD). RESULTS: Desflurane at 3% (95 +/- 13% of baseline), 6% (86 +/- 6% of baseline), and 9% (82 +/- 6% of baseline) enhanced the recovery of force after 60 min of reoxygenation as compared with the control group (50 +/- 11% of baseline). Glibenclamide (60 +/- 12% of baseline), 5-HD (57 +/- 21% of baseline), DPX (63 +/- 19% of baseline), phentolamine (56 +/- 20% of baseline), and propranolol (63 +/- 13% of baseline) abolished desflurane-induced preconditioning. In contrast, HMR 1098 (85 +/- 12% of baseline) did not modify desflurane-induced preconditioning. CONCLUSIONS: In vitro, desflurane preconditions human myocardium against simulated ischemia through activation of mitochondrial K(ATP) channels, adenosine A1 receptor, and alpha and beta adrenoceptors.     

Stimulation of both humoral and cellular immune responses to HIV-1 gp120 by interleukin-12 in Rhesus macaques

The adjuvant effect of recombinant Rhesus macaque interleukin-12 (RhIL-12) on the induction of cellular and humoral immune responses elicited by the HIV-1 subunit vaccine protein gp120 in Rhesus macaques was examined. RhIL-12 in conjunction with gp120 was given at day 0, 28 and 84 intramuscularly. Coadministration resulted in an approximate 10-fold increase in plasma anti-gp120 antibody levels as compared to levels generated in control monkeys receiving gp120 alone. Potentiation of the humoral arm of the immune response was evident by both ELISA and an antiviral bioassay. In addition, RhIL-12 was found to produce a significant increase in gp120-specific proliferative responses and in the frequency of antigen-specific IFN-gamma and IL-2 producing T cells after restimulation of PBMC with gp120 in vitro indicating that RhIL-12 potentiates cell-mediated immune responses as well. A critical finding was that during the course of the study, RhIL-12 did not induce a neutralizing antibody response to the administered cytokine. The doses of RhIL-12 were well tolerated and no detectable adverse side-effects on hematopoietic and hepatic parameters were noted. The data revealed that IL-12, when coadministered intramuscularly, acts as a potent adjuvant which is able to enhance not only cellular but also humoral immune responses to gp120 in non-human primates and may have to be considered in future HIV vaccine strategies.     

Noscapine alters microtubule dynamics in living cells and inhibits the progression of melanoma

Cellular microtubules, polymers of tubulin, alternate relentlessly between phases of growth and shortening. We now show that noscapine, a tubulin-binding agent, increases the time that cellular microtubules spend idle in a paused state. As a result, most mammalian cell types observed arrest in mitosis in the presence of noscapine. We demonstrate that noscapine-treated murine melanoma B16LS9 cells do not arrest in mitosis but rather become polyploid followed by cell death, whereas primary melanocytes reversibly arrest in mitosis and resume a normal cell cycle after noscapine removal. Furthermore, in a syngeneic murine model of established s.c. melanoma, noscapine treatment resulted in an 85% inhibition of tumor volume on day 17 when delivered by gavage compared with untreated animals (P 相似文献