Daniel Humberto Pozza

Comparative chemical study of MTA and portland cements

Portland cement has been analyzed and compared to mineral trioxide aggregate (MTA) because of their chemical similarity. The possibility of using this material as a less expensive alternative to MTA in dental practice should be considered. In view of this, the present study compared the components of a Portland cement (Votoran) to two commercial brands of MTA (Pro-Root and MTA-Angelus). Twelve specimens of each material were fabricated and examined by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) to obtain their percentage of chemical elements. The means of the chemical elements found in each material was compared by descriptive statistics. Bismuth was present only in MTA cements to provide radiopacity. In conclusion, the tested cements have similar components, which supports, as far as composition is concerned, the possible clinical use of Portland as an option to MTA.

Analysis of the Systemic Effect of Red and Infrared Laser Therapy on Wound Repair

OBJECTIVE To evaluate, using histological analysis, the systemic action and repair process of wounds produced on the back of rats and treated with red, infrared, or both lasers applied directly or indirectly to the wounds. BACKGROUND DATA Skin tissue repair and wound healing are complex processes that involve a series of dynamic events. Many benefits are associated with biomodulation using laser therapy. METHODS Thirty-six male Wistar rats were divided into four groups: control (without laser), red laser (aluminium gallium indium phosphide (AlGaInP); lambda=685 nm; phi=0.0314 cm2; CW; P=30 mW; D=20 J, time of irradiation=667 sec), infrared laser (gallium-aluminum-arsenide (GaAlAs): lambda=830 nm; phi=0.0314 cm2; CW; P=50 mW; D=20 J, time of irradiation=401 sec), and both lasers (infrared laser: GaAlAs; lambda=830 nm; phi=0.0314 cm2; CW; P=50 mW; D=10 J, time of irradiation=201 sec+red laser: AlGaInP; lambda=685 nm; phi=0.0314 cm2; CW; P=30 mW; D=10 J, time of irradiation=334 sec; total dose=20 J). Three subgroups were formed according to observation time points. Three wounds were produced on the back of each animal. Only the wound closest to the head was irradiated in the experimental groups. For the evaluation of skin reaction and wound healing, three animals of each group were killed at 3, 5, and 7 days postoperatively. The irradiation protocol established 48-hour intervals between applications, with the first application immediately after the surgical procedure. RESULTS In the red and infrared laser group, healing was more advanced in the wound located furthest from the point of laser application. The most effective healing of a proximal wound was verified in the control group on the 7th postoperative day. CONCLUSION The combined application of red and infrared lasers resulted in the most evident systemic effect on the repair of skin wounds produced in rats.

Neuronal Injury Marker ATF-3 Is Induced in Primary Afferent Neurons of Monoarthritic Rats

Activating transcription factor 3 (ATF-3) expression has been associated with several signaling pathways implicated in cellular stress response in many cell types and is usually regarded as a neuronal damage marker in dorsal root ganglia (DRG). We investigated ATF-3 expression in primary afferents in the monoarthritic (MA) model of chronic inflammatory joint pain. Immunohistochemistry revealed that ATF-3 is highly induced mainly in small and medium neurons, especially at 2 and 4 days of MA in L5 DRGs. Colocalization with calcitonin gene-related peptide (CGRP) and isolectin B4 (IB4) demonstrated that ATF-3-immunoreactive cells are mainly peptidergic. The lack of significant differences in ATF-3 and pAkt colocalization indicated that ATF-3 is probably not involved in a pAkt-mediated survival pathway. Anti-inflammatory (ketoprofen) administration failed to reverse ATF-3 induction in MA rats, but significantly increased CGRP expression. These data suggest that ATF-3 expression is definitely involved in MA, actually marking injured neurons. Some degree of neuronal damage seems to occur right from the first days of disease, mainly affecting small-to-medium peptidergic neurons. The intra-articular injection of complete Freund’s adjuvant and the generation of a neuroinflammatory environment seem to be the plausible explanation for the local nerve damage.

CO2, Er: YAG and Nd:YAG lasers in endodontic surgery

Objectives: CO2, Er:YAG and Nd:YAG lasers have been used in endodontic surgery. This in vitro study evaluated 1% Rhodamine B dye penetration using computer-assisted morphometry (ImageTool Software®) of 108 endodontically treated human permanent canines. Material and methods: Teeth were divided into 9 groups according to the technique used: A: 90-degree apicoectomy with bur, root-end cavity preparation with ultrasound and filled with MTA; B: 90-degree apicoectomy with bur, root-end cavity prepared with ultrasound and filled with MTA, and treatment of apical surface with CO2 laser (1 W, CW/CW); C: 90-degree apicoectomy with bur, and treatment of apical surface with Nd:YAG laser (150 mJ, 10 Hz); D: 90-degree apicoectomy with bur, and treatment of apical surface with CO2 laser (1 W, CW/CW); E: apicoectomy with Er:YAG laser (400 mJ, 10 Hz), root-end cavity prepared with ultrasound and filled with MTA; F: apicoectomy with Er:YAG laser (400 mJ, 10 Hz) and treatment of apical surface with Nd:YAG laser (150 mJ, 10Hz); G: apicoectomy with CO2 laser (5W, CW/SP), root-end cavity prepared with ultrasound and filled with MTA; H: irradiation of apical end with CO2 laser (1 W, CW/CW); I: irradiation of apical end with Nd:YAG laser (150 mJ, 10 Hz). Results: Dye penetration was found in all specimens at different rates, the lowest penetration occurring in groups C (16.20%), B (17.24%) and F (17.84%). Conclusions: Groups B, C and F represent the best technical sequences to perform endodontic surgery.

Targeting HER family in HER2-positive metastatic breast cancer: potential biomarkers and novel targeted therapies

HER2-targeted therapies have radically changed the prognosis of HER2-positive breast cancer over the last few years. However, resistance to these therapies has been a constant, leading to treatment-failure and new tumor progression. Recently, the kinase-impaired HER3 emerged as a pivotal player in oncogenic signaling, with an important role in both non-treated progression and treatment response. HER2/HER3 dimerization is required for full signaling potential and constitutes the key oncogenic unit. Also, when inhibiting PI3K/AKT pathway (as with anti-HER2 drugs) feedback mechanisms lead to a rebound in HER3 activity, which is one of the main roads to resistance. As current strategies to treat HER2-positive breast cancer are unable to inhibit this feedback response, two great promises emerged: the combination of targeted-therapies and drugs targeting HER3. In this article HER2 and HER3-targeted drugs and possible combinations between them, as well as the biomarkers to predict and monitor these drugs effect, are reviewed.

Retinoblastoma and p53 protein expression in pre-malignant oral lesions and oral squamous cell carcinoma

The retinoblastoma (Rb) and p53 genes play a fundamental role in cell cycle mechanisms, and their deregulation is related to many steps of oral cancer carcinogenesis. This study was conducted to evaluate the expression of the p53 and Rb proteins in malignant and pre-malignant oral cavity lesions. This retrospective study was conducted at the Federal University of Bahia, Salvador, Brazil, and the Molecular Biology Laboratory of the Otorhinolaryngology Department at the University of Heidelberg, Heidelberg, Germany. Excisional biopsy samples of oral cavities were collected from patients with suspected oral lesions. The samples were processed by immunohistochemistry to be classified by a semi-quantitative score: samples with a ≤ 10% positivity were considered to have weak/negative expression (-); those with 11-50% positivity, moderate expression (+); and those with >50% positivity, high expression (++). Seventy-one patients were studied (75% male; median age, 52 years; range, 24-84). Of the samples studied, 59.4% were oral squamous cell carcinoma (OSCC) and 40.6% were pre-neoplastic lesions (leukoplakia and actinic cheilitis). OSCC presented higher expression of Rb protein compared to pre-malignant lesions: 75 vs. 25% (p<0.001). Pre-neoplastic lesions presented higher expression of p53 protein compared to OSCC lesions: 55.2 vs. 44.8% (p = 0.030). Despite the small number of samples, the expression of these cell cycle biomarkers (p53 and Rb protein) in excisional biopsies suggests that molecular lesion assessment can determine pre-malignant lesions, and that its use may improve the clinical and surgical treatment of early lesions. Thus, p53 protein expression may be related to the early steps of carcinogenesis in OSCC. Finally, a higher Rb expression was also observed in malignant lesions.

Nociceptive behaviour upon modulation of mu-opioid receptors in the ventrobasal complex of the thalamus of rats.

&NA; The role of mu‐opioid receptors (MORs) in the inflammatory pain processing mechanisms within the ventrobasal complex of the thalamus (VB) is not well understood. This study investigated the effect of modulating MOR activity upon nociception, by stereotaxically injecting specific ligands in the VB. Nociceptive behaviour was evaluated in two established animal models of inflammatory pain, by using the formalin (acute and tonic pain) and the ankle‐bend (chronic monoarthritic pain) tests. Control (saline intra‐VB injection) formalin‐injected rats showed acute and tonic pain‐related behaviours. In contrast, intrathalamic administration of [D‐Ala2, N‐Me‐Phe4, Gly5‐ol]‐enkephalin acetate (DAMGO), a MOR‐specific agonist, induced a statistically significant decrease of all tonic phase pain‐related behaviours assessed until 30–35 min after formalin hind paw injection. In the acute phase only the number of paw‐jerks was affected. In monoarthritic rats, there was a noticeable antinociceptive effect with approximately 40 min of duration, as denoted by the reduced ankle‐bend scores observed after DAMGO injection. Intra‐VB injection of D‐Phe‐Cys‐Tyr‐D‐Trp‐Orn‐Thr‐Pen‐Thr‐NH2 (CTOP), a specific MOR antagonist, or of CTOP followed, 10 min after, by DAMGO had no effects in either formalin or ankle‐bend tests. Data show that DAMGO‐induced MOR activation in the VB has an antinociceptive effect in the formalin test as well as in chronic pain observed in MA rats, suggesting an important and specific role for MORs in the VB processing of inflammatory pain.

MicroRNAs in lung cancer

Lung cancer (LC) is a serious public health problem responsible for the majority of cancer deaths and comorbidities in developed countries. Tobacco smoking is considered the main risk factor for LC; however, only a few smokers will be affected by this cancer. Current screening methods are focused on identifying the early stages of this malignancy. Thus, new data concerning the roles of microRNA alterations in inflammation, epithelial-mesenchymal transition and lung disease have increased hope about LC pathogenesis, diagnosis, treatment and prognosis. MicroRNA mechanisms include angiogenesis promotion, cell cycle regulation by modulating cellular proliferation and apoptosis, and migration and invasion inhibition. In this context, this manuscript reviews the current information about many important microRNAs as they relate to the initiation and progression of LC.

Prospective study of a group of pre-university students evaluating anxiety and depression relationships with temporomandibular disorders.

Objectives: The aim of this prospective longitudinal study was to evaluate the relationships between anxiety, depression, and temporomandibular disorders (TMD) in a sample of pre-university students submitted to a stressful event. Study Design: 153 students from a pre-university course (82 females and 71 males between 16 and 31 years old) were given a survey about TMD symptoms and a survey about anxiety and depression scale at the beginning and the end of the preparatory course (August 2009-T1, and November 2009-T2). Results: Results were analyzed using a chi-square test and Odds Ratio (OR), significance level of α = 0.05. Statistical significance were found to depression rates in students with TMD (16% on T1 and 26% on T2, p = 0.001) as well as in general sample (12% on T1 and 22% on T2, p = 0.009), anxiety and TMD symptoms presented constant rates in both periods. Increased risk of having TMD were found in participants with anxiety (OR 2.6 in T2 and 5.6 in T1) and depression (2.0 in T2 and 3.3 in T1), but only anxiety reach statistical significance in both periods. Conclusions: TMD symptoms were a fluctuating variable that exchange between some individuals of this study. Independently of the TMD, depression rates significant increased in the evaluated period. Finally, anxiety was the psychological symptom related to the increased risk of having TMD. Key words:Temporomandibular disorders, anxiety, depression, orofacial pain, hospital anxiety and depression scale.

Spared nerve injury model to study orofacial pain

Background & objectives: There are many difficulties in generating and testing orofacial pain in animal models. Thus, only a few and limited models that mimic the human condition are available. The aim of the present research was to develop a new model of trigeminal pain by using a spared nerve injury (SNI) surgical approach in the rat face (SNI-face). Methods: Under anaesthesia, a small incision was made in the infraorbital region of adult male Wistar rats. Three of the main infraorbital nerve branches were tightly ligated and a 2 mm segment distal to the ligation was resected. Control rats were sham-operated by exposing the nerves. Chemical hyperalgesia was evaluated 15 days after the surgery by analyzing the time spent in face grooming activity and the number of head withdrawals in response to the orofacial formalin test. Results: SNI-face rats presented a significant increase of the formalin-induced pain-related behaviours evaluated both in the acute and tonic phases (expected biphasic pattern), in comparison to sham controls. Interpretation & conclusions: The SNI-face model in the rat appears to be a valid approach to evaluate experimental trigeminal pain. Ongoing studies will test the usefulness of this model to evaluate therapeutic strategies for the treatment of orofacial pain.