Effects of non-thermal atmospheric plasma treatment on dentin wetting and surface free energy for application of universal adhesives

Objectives

The study aims to evaluate the effects of non-thermal atmospheric plasma (NTAP) treatments on dentin wetting and surface free energy (SFE) and compare the effects of NTAP treatment, etch-and-rinse, and self-etch protocols for application of universal adhesives.

Materials and methods

Mid-coronal dentin of intact third molars was used to measure contact angles of distilled water, ethylene-glycol, and diiodomethane and calculate SFE following different NTAP preset treatments (feeding gas consisting of pure He, He + 1% O₂, He + 1.5% O₂), power input (1 or 3 W), and tip-to-surface distance (2, 4, or 8 mm). Contact angles of reference liquids and SFE of dentin following He + 1.5% O₂ at 3-W and 4-mm treatment was compared to phosphoric acid etching. Contact angles of Single Bond Universal (SBU; 3M ESPE) and Clearfil Universal Bond (CUB; Kuraray Noritake) were measured following NTAP, etch-and-rinse, and self-etch protocols.

Results

NTAP significantly reduced contact angles of reference liquids and increased dentin SFE compared to untreated dentin (p < 0.05). O₂ intensified the effect of He NTAP (p < 0.05). NTAP and phosphoric acid increased dentin polarity and Lewis base surface characteristics. Phosphoric acid increased contact angles of adhesives compared to the self-etch protocol (p < 0.05). NTAP resulted in lower adhesive contact angles than phosphoric acid, the difference being statistically significant for CUB (p < 0.05). Compared to the self-etch protocol, NTAP slightly reduced CUB contact angle but not that of SBU (p > 0.05).

Conclusions

He NTAP with and without O₂ increased dentin wetting and SFE, surpassing the effect of phosphoric acid and lowering adhesive contact angles. NTAP produced no apparent micro-morphological changes on dentin surface comparable to acid etching.

Clinical significance

NTAP treatment of dentin prior to adhesive application increases dentin wetting and surface free energy facilitating better adhesive distribution on dentin surface compared to phosphoric acid etching and similar to the “self-etch” application protocol.

     

Inhibition of induction of natural killer activity in mice by general anesthesia (Avertin): role of interferon.

We have previously reported that general anesthesia (Avertin) inhibits the induction of natural killer (NK) cell activity following administration of Poly I:C in vivo. Since Poly I:C has been shown to increase NK activity through the induction of interferon (IFN), the current study examines the role of IFN in this inhibition. The data suggest that (i) anesthesia does not affect the ability of Poly I:C to induce endogenous IFN synthesis (serum IFN levels are unaltered by anesthesia) and (ii) anesthesia is capable of inhibiting stimulation of NK activity induced directly by treatment with IFN either in vivo or in vitro. The duration of the former effect was at least 10 days, with complete recovery by Day 14 after anesthesia. Interestingly, NK activity stimulated by IFN prior to anesthesia was not significantly altered. In view of the increasingly evident role of NK cells in anti-tumor and anti-infectious host defenses, their inertness to stimulation in the post-anesthesia period may be a significant contributing factor to the clinically observed postoperative morbidity. Thus, preanesthesia stimulation of NK activity with IFN may be of therapeutic value.     

Degenerative neurological disorders associated with deficiency of glutamate dehydrogenase

Summary The activity of glutamate dehydrogenase, the enzyme of glutamate degradation, was measured in platelets of 27 healthy controls and 85 patients with different degenerative cerebellar and/or basal ganglia disorders. A group of 7 patients was selected with slowly progressive multiple-system atrophy, in whom a clinical diagnosis of olivopontocerebellar atrophy appeared tenable, with decreased activity of glutamate dehydrogenase (38% of the mean control value). In 4 patients data on inheritance were compatible with the genetic pattern of autosomal recessive inheritance, while 3 patients were sporadic cases. In an effort to define this group of patients more precisely, it is suggested that decreased activity of glutamate dehydrogenase induces an increase in extracellular glutamate levels in the central nervous system with subsequent development of excitotoxicity.     

Adsorption and dissolution behavior of human plasma fibronectin on thermally and chemically modified titanium dioxide particles.

Titanium is known for its biocompatibility and is widely used in dental and orthopedic reconstructive surgery. There are reports that osteointegration of these implants is not optimal. The objective of this study was to modify titanium dioxide particles and examine the resultant effects on protein adsorption to these altered surfaces using a model cell binding protein, human plasma fibronectin (HPF). HPF is an important matrix glycoprotein that plays a major role in cell and protein attachment, Titanium dioxide surfaces were modified by heating the titanium dioxide powder at 800 degrees C for 1 h or treating with an oxidizing agent: peroxide in ammonium hydroxide followed by peroxide in hydrochloric acid. Oxidized and control samples were further treated with 9:1 butanol:water for 30 min. Brunauer-Emmett-Teller showed no change in particle surface area as a result of thermal or chemical treatment. Hydrophobicity increased with butanol treatment of titanium dioxide. Diffuse reflectance Fourier transform infrared spectroscopy showed the presence of -CH2 and -CH3 vibrations in the region of 2850-3000 cm(-1) for both the heated, butanol and peroxide/butanol-treated samples. The absence of increased C-O and O-C=O features as determined by electron spectroscopy for chemical analysis indicates that butanol adsorption is not occurring via an esterification mechanism. The interaction between butanol and pre-heated or peroxide-treated titanium dioxide may be one of association (weak electrostatic and/or Van der Waals forces) rather than direct ionic bonding. Maximum HPF adsorption on modified or unmodified titanium dioxide occurred within 30 min, with greater protein adsorption occurring on butanol-treated samples. Desorption was minimal with all modifications. Zeta potential measurements showed that HPF adsorption caused an increase in the negative zeta potential with the greatest change noted for the butanol-treated samples. These findings suggest that wettability and surface charge both play an important role in protein adsorption to titanium dioxide. Thus, by modifying the physico-chemical properties of titanium dioxide surfaces, it may be possible to alter protein adsorption and hence optimize cell attachment.     

Immunohistochemical demonstration of mitochondria in routinely processed tissue using a monoclonal antibody

We report results obtained using the monoclonal antibody M-II 68, which recognizes inner mitochondrial membrane in routinely processed (formalin-fixed and paraffin-embedded) tissue by light microscopic immunohistochemistry. In ten normal brains, the range of immunoreactivity in various cell types and locations was defined. The most intense staining was observed in Purkinje cells, in neurons of cranial nerve nuclei, pons and substantia nigra, as well as in choroid plexus epithelial cells. By comparison with this control group, one case of primary mitochondrial encephalomyopathy exhibited increased staining of endothelial and vascular smooth muscle cells, choroid plexus epithelial cells, and neurons of various locations. Scattered ragged-red fibres were heavily labelled in one case of mitochondrial myopathy, while ten muscles without mitochondriopathy were left unstained. Our method is able to detect accumulations of mitochondria and increases in mitochondrial cristae density. It could prove useful for differential diagnosis of routine biopsy material and for clarification of cell types involved in mitochondrial cytopathies.     

Supplementation with Octacosanol Affects the Level of PCSK9 and Restore Its Physiologic Relation with LDL-C in Patients on Chronic Statin Therapy

Dietary supplementation with sugar cane derivates may modulate low-density lipoprotein cholesterol (LDL-C) and proprotein convertase subtilisin/kexin type 9 (PCSK9) levels. The purpose of this study was to determine if dietary supplement (DS), containing Octacosanol (20 mg) and vitamin K2 (45 µg), could restore the disrupted physiologic relation between LDL-C and serum PCSK9. Double-blind, randomized, placebo-controlled, single-center study including 87 patients on chronic atorvastatin therapy was conducted. Eighty-seven patients were randomized to receive DS (n = 42) or placebo (n = 45), and followed for 13 weeks. Serum PCSK9 levels, lipid parameters and their relationship were the main efficacy endpoints. The absolute levels of PCSK9 and LDL-C were not significantly different from baseline to 13 weeks. However, physiologic correlation between % change of PCSK9 and % change of LDL-C levels was normalized only in the group of patients treated with DS (r = 0.409, p = 0.012). This study shows that DS can restore statin disrupted physiologic positive correlation between PCSK9 and LDL-C. Elevated PCSK9 level is an independent risk factor so controlling its rise by statins may be important in prevention of cardiovascular events.     

Role of nimodipine in the therapy of subarachnoid and intracerebral hemorrhage

Syndromes of intracranial hemorrhage, and particularly subarachnoidal, i.e., intracerebral hemorrhage (SAH and IH) present clinical entities that are the most severe conditions in neurology. Timely recognition, diagnosis and adequate therapy are imperative. The most important factor that aggravates an already difficult prognosis of those entities is cerebral vasospasm. Upon the presented facts, the aim of this investigation was to establish the value and role of administration of selective calcium channel blocker--nimodipine in patients with SAH and IH compared to the degree of neurological and functional impairment, as well as the recovery of the function of consciousness compared to the patients with those syndromes from an earlier period, who were not treated with this medicament. Investigation comprised 30 patients who received nimodipine and 20 patients without this agent in therapeutic program. Results of the investigation confirmed significant difference concerning the neurological recovery, improvement of functional capability and recovery or consciousness disturbances, respectively, in patients who received nimodipine compared to the group without this agent. It can be concluded that nimodipine as calcium channel blocker with multitopic pharmacological effects on mechanism of SAH or IH development, respectively, as well as on the development of complications of those syndromes, particularly to the development of vasospasm and reactive ischemia, with the improvement of hemorrheologic disorders deserves to be included as the unavoidable segment of therapeutic program of SAH and IH syndrome immediately after clinical phenomenology is revealed.     

Secondary neurosurgical management of craniocerebral war injuries

In Belgrade Military Medical Academy 88 males and 1 female (aged 13-55, average 28.6 years) with war craniocerebral injuries (CCI) were secondarily neurosurgically treated from October 1991 trough December 1992. Primary neurosurgical management of these patients was performed in war hospitals in former Yugoslavia. Out of 89 patients, 78 had penetrating, and 11 closed CCI. Out of 55 patients with penetrating CCI who underwent surgery, intracranial debridement was performed in 34 patients. All patients with severe CCI (GCS = 3-8) were severely by disabled or died, and in the majority of patients with minor CCI (GCS = 13-15) the outcome was good (p < 0.01). Statistical analysis showed no significant correlation between the extent of cerebral lesion and the outcome of penetrating CCI (p > 0.05). Eight (10.3%) patients with penetrating CCI died. The outcome of war CCI mostly depended on the severity of injury.     

Correlation of serum hormone concentrations in maternal and umbilical cord samples.

Evidence suggests that adult cancer risk of hormonally related tumors may be influenced by the in utero environment, and most speculation on the biological mechanism has focused on the hormonal component. Epidemiological studies investigating the biological nature of pregnancy and maternal factors associated with offspring's cancer risk have relied on maternal hormone measurements. The degree to which maternal hormone levels represent the fetal environment, however, is not widely known. Pregnancy estrogen, androstenedione, testosterone, dehydroepiandrosterone (DHEA), and DHEA-sulfate concentrations were measured in maternal and mixed umbilical cord sera from 86 singleton pregnancies. Spearman correlations between maternal and cord hormone levels generally ranged between 0.2 and 0.3. The correlation was 0.26 for estriol, the estrogen of highest concentration in pregnancy, and 0.27 for estradiol, the most biologically active estrogen. The correlations between mother and offspring for the estrogens and DHEA appeared similar for males and females, whereas there was a suggestion that the maternal-umbilical cord correlations for other androgens varied in magnitude by fetal sex, and all correlations appeared higher in pregnancies lasting <38 weeks compared with longer gestational lengths, although these stratified findings may have been attributable to chance. These data show a moderate degree of correlation in hormone concentrations between the maternal and fetal circulation. Studies using maternal hormone concentrations as a proxy for the fetal environment should consider the misclassification resulting with the use of this marker.