FURTHER INSIGHTS TOWARD VITAMIN C DETERMINATION AND STABILITY. PROPOSAL OF A NEW QUANTIFICATION METHOD

This work aimed at an evaluation of the classical iodine method for quantification of vitamin C (L-ascorbic acid) in fruit juices, as well as at a search into the stability of this so popular vitamin under different conditions of pH, temperature and light exposition, in addition to a proposal of a new quantification method. Our results point to the persistent reversibility of the blue color of the starch-triiodide complex at the end point when using the classical iodine titration, and the overestimation of the true vitamin concentration in fruit juices. A new quantification method is proposed in order to overcome this problem. Surprising conclusions were obtained regarding the controversial stability of L-ascorbic acid toward atmospheric oxygen, at low pH, even in fruit juice and at room temperature, showing that the major problem concerned with aging of fruit juices is proliferation of microorganisms rather than expontaneous oxidation of L-ascorbic acid.

Multiple imaging radiography at LNLS

An analyzer-based X-ray phase-contrast imaging (ABI) setup has been mounted at the Brazilian Synchrotron Light Laboratory (LNLS) for multiple imaging radiography (MIR) purposes. The algorithm employed for treating the MIR data collected at LNLS is described, and its reliability in extracting the distinct types of contrast that can be obtained with MIR is demonstrated by analyzing a test sample (thin polyamide wire). As a practical application, the possibility of studying ophthalmic tissues, corneal sequestra in this case, via MIR is investigated. (C) 2007 Elsevier B.V. All rights reserved.

Redescription of Amblyomma varium Koch, 1844 (Acari : Ixodidae) based on light and scanning electron microscopy

Amblyomma varium Koch, 1844 is a Neotropical tick, known as the `sloth`s giant tick`, with records from southern Central America to Argentina. It is found almost exclusively on mammals of the families Bradypodidae and Magalonychidae (Xenarthra). Differences exist in discussions with regard to the dentition of the female hypostome being either 3/3 or 4/4. The male was also originally described as having a short spur on coxa IV, but some specimens recently collected from different Brazilian localities have this spur three times longer. These differences beg the question of whether there is more than one species included under this taxon. In order to answer this question and to clarify the taxonomic characters of this species, 258 adult specimens were examined, and a redescription of male and female based on light and scanning electron microscopy is provided. In addition, DNA was extracted from males with either a long or a short spur on coxa IV to help settle this question for future investigations on their taxonomy. The morphological study showed that the dental formula pattern for males and females is 3/3 and 4/4, respectively. When sequenced, the 12 S rDNA genes of both A. varium males with long and short spurs on coxa IV were found to be identical, indicating that the length of the spurs on coxa IV is likely to be an intraspecifically polymorphic character of this species.

An integrated database on ticks and tick-borne zoonoses in the tropics and subtropics with special reference to developing and emerging countries

Tick-borne zoonoses (TBZ) are emerging diseases worldwide. A large amount of information (e.g. case reports, results of epidemiological surveillance, etc.) is dispersed through various reference sources (ISI and non-ISI journals, conference proceedings, technical reports, etc.). An integrated database-derived from the ICTTD-3 project (http://www.icttd.nl)-was developed in order to gather TBZ records in the (sub-)tropics, collected both by the authors and collaborators worldwide. A dedicated website (http://www.tickbornezoonoses.org) was created to promote collaboration and circulate information. Data collected are made freely available to researchers for analysis by spatial methods, integrating mapped ecological factors for predicting TBZ risk. The authors present the assembly process of the TBZ database: the compilation of an updated list of TBZ relevant for (sub-)tropics, the database design and its structure, the method of bibliographic search, the assessment of spatial precision of geo-referenced records. At the time of writing, 725 records extracted from 337 publications related to 59 countries in the (sub-)tropics, have been entered in the database. TBZ distribution maps were also produced. Imported cases have been also accounted for. The most important datasets with geo-referenced records were those on Spotted Fever Group rickettsiosis in Latin-America and Crimean-Congo Haemorrhagic Fever in Africa. The authors stress the need for international collaboration in data collection to update and improve the database. Supervision of data entered remains always necessary. Means to foster collaboration are discussed. The paper is also intended to describe the challenges encountered to assemble spatial data from various sources and to help develop similar data collections.

Behavioural responses of heifers to ACTH injections

The objective of this study was to investigate behavioural changes in Holstein heifers caused by exogenous adrenocorticotropic hormone (ACTH) administration. Twelve 11-month-old heifers were submitted to either a single saline or ACTH injection and then the treatments were switched after 3 days (n = 12 heifers/treatment). Heifers were in full view throughout the experimental period and recordings started immediately after ACTH and saline administration (injection corresponded to time 0 min), with general activity patterns of each heifer recorded on videotape for 24 h. Behavioural results during the first two experimental hours showed that heifers were less active and spent more time lying following ACTH than after saline treatment (P = 0.04). Also, heifers spent significantly less time ruminating immediately following ACTH injection (P = 0.05). However, feed intake measured after 4 and 24 h was similar between treatments (P > 0.05). Overall, there was no significant influence of ACTH treatment on frequency or duration of behaviours during the 4- and 24-h periods following injection (P > 0.05). The rapid and minimal effect of ACTH injection on behaviour suggests that peripheral administration of ACTH can be used to measure reactivity of the adrenal cortex without inducing biologically significant consequences. (C) 2010 Elsevier B.V. All rights reserved.

Redescription of the female, description of the male, and several new records of Amblyomma parkeri (Acari: Ixodidae), a South American tick species

The tick Amblyomma parkeri Fonseca and Arago was described in 1952, based on female and immature ticks collected in the states of So Paulo and Santa Catarina, Brazil. Thereafter, there has been no further report of A. parkeri, and the male has remained unknown. Herein, we examined ticks collected on porcupines from a locality in the state of So Paulo. Some of the ticks were identified as Amblyomma longirostre (Koch, 1844), whereas others as A. parkeri, including male specimens, for which we provide the first description. We also provide additional reports of A. parkeri after examining collections of A. longirostre and Amblyomma geayi Neumann, 1899 from different tick collections. Morphological evidence to support the original description of A. parkeri is presented, supported by molecular analyses of portions of the 16S rRNA and 12S rRNA mitochondrial genes. Morphological particularities to separate A. parkeri, A. longirostre, and A. geayi are provided.

Micro-tensile bond strength to bovine sclerotic dentine: Influence of surface treatment

Objective: The objective of this study was to evaluate the influence of the surface treatment and acid conditioning (AC) time of bovine sclerotic dentine on the micro-tensile bond strength (mu-TBS) to an etch and rinse adhesive system. Materials and method: Thirty-six bovine incisors were divided into six groups (n = 6): G1 sound dentine submitted to AC for 15 s; G2-G6 sclerotic dentine: G2-AC for 15 s; G3-AC for 30 s; G4-EDTA and AC for 15 s; G5-diamond bur and AC for 15 s; G6-diamond paste and AC for 15 s. An adhesive system was applied to the treated dentine surfaces followed by a hybrid composite inserted in increments and light cured. After 24 h storage in water at 37 degrees C, the specimens were perpendicularly cut with a low-speed diamond saw to obtain beams (0.8 mm x 0.8 mm cross-sectional dimensions) for mu-TBS testing. Data was compared by ANOVA followed by Tukey`s test (P <= 0.05). Results: The mean L-TBS was G1: 18.87 +/- 5.36 MPa; G2: 12.94 +/- 2.09 MPa; G3: 11.73 +/- 0.64 MPa; G4: 11.14 +/- 1.50 MPa; G5: 22.75 +/- 4.10 MPa; G6: 22.48 +/- 2.71 MPa. G1, G5 and G6 presented similar bond strengths significantly higher than those of all other groups. Conclusion: The surface treatment of sclerotic dentine significantly influenced the bond strength to an adhesive system. Mechanical treatment, either using a diamond bur or a diamond paste was able to improve bonding to bovine sclerotic dentine, reaching values similar to bonding to sound dentine. (C) 2008 Elsevier Ltd. All rights reserved.

Morphological analysis of human and bovine dentine by scanning electron microscope investigation

Objective: The objective of this study was to compare the superficial morphology of bovine and human sclerotic dentine. Design: For the morphological analysis, bovine (n = 3) and human (n = 3) incisors exhibiting exposed dentine were used. Dentine presented characteristics of sclerosis: brownish, smooth and shiny-the vitreous appearance. The teeth were prepared for assessment on a scanning electron microscope (SEM). Three pre-determined areas of each sample were submitted to SEM. The number of open tubules per area was obtained from the electron micrographs (n = 9 per group) for comparison purposes. Results: The number of open tubules in both species compared were similar (p > 0.05). Human dentine presented 31.89 +/- 23.94 open tubules per area, whereas bovine dentine showed 30.33 +/- 18.14 open tubules per area. Conclusion: Based on the results, we concluded that dentine exposed at the incisal surface of human and bovine teeth presented similar clinical and micro-morphological aspects, represented by surfaces with equivalent numbers of open dentinal tubules. (C) 2007 Elsevier Ltd. All rights reserved.

Rare case of unifocal Langerhans cell histiocytosis in four-month-old child

Langerhans cell histiocytosis (LCH) comprises a group of disorders, the common feature of which is Langerhans cell proliferation. The clinical presentation is highly varied. The severity and prognosis of the disease are dependent on the type and extent of organ involvement. This paper reports a rare case of a four-month-old white male with unifocal LCH limited exclusively to the mandible, discussing the diagnosis, radiographic and immunohistochemical aspects, treatment and monitoring multidisciplinary of the case. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

Electrocardiographic Alterations During Endosseous Implant Placement Performed with Local Anesthetic Agents

Purpose: The purpose of this study was to analyze electrocardiographic alterations during dental implant surgeries when local anesthetic agents were used. Materials and Methods: Twenty implants were placed in 18 healthy patients. An electrocardiogram and Wincardio software were used to gather recordings from 12 static leads every 2 minutes, continuously record coronary artery (D2) derivations, and automatically measure the following electrocardiographic parameters: heart rate, duration and amplitude of the P wave, PR segment duration, ST segment deviation, QRS complex duration, and duration of the RR, QT, and corrected QT (QTc) intervals. Results: Analysis of variance of the values obtained at the different stages showed significant differences (P < .05) for the heart rate and for the duration of the RR and QT intervals. The heart rate increased during the anesthesia, incision, and bone drilling stages, reaching a peak during drilling. Duration of the RR and QT intervals decreased during the incision and drilling stages. Among the electrocardiographic parameters individually assessed, several altered values were found for the duration of the P wave, the QRS complex, and the QT and QTc intervals. Sinusal tachycardia and bradycardia, sinusal arrhythmia, supraventricular extrasystole, ventricular extrasystole, and T-wave inversion were detected. Conclusion: Dental implant placement surgery may induce electrocardiographic alterations. The most frequently found arrhythmias were extrasystole and sinusal tachycardia. The anesthesia, incision, and bone drilling stages exhibited the highest heart rate values and the shortest durations of the RR and QT intervals. INT J ORAL MAXILLOFAC IMPLANTS 2009;24:412-418

Understanding the impact of divalent cation substitution on hydroxyapatite: An in vitro multiparametric study on biocompatibility

Hydroxyapatite (HA), a stable and biocompatible material for bone tissue therapy, may present a variable stoichiometry and accept a large number of cationic substitutions. Such substitutions may modify the chemical activity of HA surface, with possible impact on biocompatibility. In this work, we assessed the effects of calcium substitution with diverse divalent cations (Pb(2+), Sr(2+), Co(2+), Zn(2+), Fe(2+), Cu(2+), or Mg(2+)) on the biological behavior of HA. Physicochemical analyses revealed that apatite characteristics related to crystallinity and calcium dissolution/uptake rates are very sensitive to the nature of cationic substitution. Cytocompatibility was evaluated by mitochondrial activity, membrane integrity, cell density, proapoptotic potential, and adhesion tests. With the exception of Zn-HA, all the substituted HAs induced some level of apoptosis. The highest apoptosis levels were observed for Mg-HA and Co-HA. Cu-HA was the only material to impair simultaneously mitochondrial activity, membrane integrity, and cell density. The highest relative cell densities after exposure to the modified HAs were observed for Mg-HA and Zn-HA, while Co-HA significantly improved cell adhesion onto HA surface. These results show that changes on surface dissolution caused by cationic substitution, as well as the increase of metal species released to biological media, were the main responsible factors related to alterations on HA biocompatibility. (C) 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 98A: 351-358, 2011.

Effect of 4% titanium tetrafluoride solution on dental erosion by a soft drink: An in situ/ex vivo study

Objective: This in situ/ex vivo study assessed the effect of titanium tetrafluoride (TiF4) on permanent human enamel subjected to erosion. Design: Ten volunteers took part in this study performed in two phases. In the first phase (ERO), they wore acrylic palatal appliances containing two enamel blocks, divided into two rows: TiF4 (F) and no-TiF4 (no-F). During the 1st day, the formation of a salivary pellicle was allowed. In the 2nd day, the TiF4 solution was applied on one row (ERO + F), whereas on the other row no treatment was performed (ERO + no-F). From 3rd until 7th day, the blocks were subjected to erosion, 4x per day. In the 2nd phase (no-ERO), the volunteers wore acrylic palatal appliances containing one enamel block, during 2 days, to assess the effect of TiF4 only (no-ERO + F). Enamel alterations were determined using profilometry (wear), microhardness (%SMHC) tests, scanning electron microscope and microprobe analysis. The %SMHC and wear were tested using ANOVA and Tukey`s post hoc tests (p < 0.05). Results: The mean of %SMHC and wear ( mu m) values ( +/- S.D.) were, respectively: ERO + F -73.32 +/- 5.16(A)/2.40 +/- 0.60(a); ERO + no-F -83.49 +/- 4.59B/1.17 +/- 0.48(b) and no-ERO + F -67.92 +/- 6.16(A)/0.21:E 0.09(c). In microscope analysis, the no-F group showed enamel with honeycomb appearance. For F groups, it was observed a surface coating with microcracks. The microprobe analysis revealed the presence of the following elements (%) in groups ERO + F, ERO + no-F and no-ERO + F, respectively: Ca (69.9, 72.5, 66.25); P (25.9, 26.5, 26.06); Ti (3.0, 0, 5.93). Conclusions: The TiF4 was unable to reduce dental erosion. (c) 2007 Elsevier Ltd. All rights reserved.

Effect of Fluoridated Water on Plasma Insulin Levels and Glucose Homeostasis in Rats with Renal Deficiency

Glucose intolerance in fluorosis areas and when fluoride is administered for the treatment of osteoporosis has been reported. Controlled fluoridation of drinking water is regarded as a safe and effective measure to control dental caries. However, the effect on glucose homeostasis was not studied so far. The aim of this study was to evaluate the effect of the intake of fluoridated water supply on glucose metabolism in rats with normal and deficient renal function. Male Sprague-Dawley rats were divided into eight groups of four rats. Renal insufficiency was induced in four groups (NX) which received drinking water containing 0, 1, 5, and 15 ppm F (NaF) for 60 days. Four groups with simulated surgery acted as controls. There were no differences in plasma glucose concentration after a glucose tolerance test between controls and NX rats and among rats with different intakes of fluoride. However, plasma insulin level increased as a function of fluoride concentration in drinking water, both in controls and in NX rats. It is concluded that the consumption of fluoridated water from water supply did not affect plasma glucose levels even in cases of animals with renal disease. However, a resistance to insulin action was demonstrated.

Short-term in situ/ex vivo study of the anticariogenic potential of a resin-modified glass-ionomer cement associated with adhesive systems

Objective: As resin-modified glass-ionomer cement (RMGIC) is an adhesive material, its association to dentin bonding agents (DBAs) was previously proposed. This study investigated the adjunctive behavior of an RMGIC with etch-and-rinse bonding systems under in situ/ex vivo cariogenic challenge. Method and Materials: Bovine enamel blocks (3 3 2 mm) were randomly assigned to group VP, Vitremer + its own primer (3M ESPE); group VSB, Vitremer + Single Bond (3M ESPE); and group VPB, Vitremer + Prime & Bond 2.1 (Dentsply). Two blocks of each group were randomly placed in an acrylic palatal appliance, so each appliance included six blocks. Volunteers (n = 10) wore these appliances according to given instructions to promote a sucrose challenge eight times/day for 15 days. After this period, the blocks were removed from the devices and cleaned, and demineralization was assessed through longitudinal microhardness analysis (Knoop indenter, 25 g/5 s). Data were submitted to three-way ANOVA and Tukey test (P < .05). Results: No treatment was able to completely avoid demineralization. All materials showed a statistically significant difference in mineral loss when the microhardness on the outer enamel was compared with deeper regions (P < .05). Conclusion: Association of the tested RMGICs with etch-and-rinse DBAs did not seem to be more beneficial against caries than the conventional treatment with RMGIC. (Quintessence Int 2010; 41: e192-e199)

Bacterial leakage in obturated root canals-part 2: a comparative histologic and microbiologic analyses

Objective. In this study, presence of dentin infection in root canals, obturated with 4 techniques submitted to the bacterial leakage test, was evaluated using histologic methods. Study design. The canals of palatal roots of 160 molars were instrumented and divided into different groups, according to the obturation technique used (lateral condensation, MicroSeal system, Touch `n Heat + Ultrafil, and Tagger`s hybrid technique) and extent of the remaining obturation material (5 mm and 10 mm). Ten additional roots were used as control samples. The roots were sterilized in ethylene oxide and mounted on a device for evaluation of bacterial leakage using the bacteria Enterococcus faecalis for 120 days. After the leakage test, roots were microscopically analyzed for the presence of dentin infection in the root canals and dentinal tubules. Results. A total of 154 specimens were analyzed using both methodologies in the experimental groups; 50 root canals (32.4%) showed bacterial leakage at the end of the experimental period, and 118 (76.6%) showed the presence of bacteria in the root canals using the histologic criteria. The lateral condensation technique allowed lower penetration of bacteria in the root canals and dentinal tubules, followed by Touch `n Heat + Ultrafil, MicroSeal, and Tagger`s hybrid technique, which allowed significantly greater penetration of bacteria. Root canals with 10 mm of remaining obturation material presented similar bacterial penetration as root canals with 5 mm. Conclusions. Even when an adequate seal of the apical foramen was shown by the absence of turbidity in the bacterial leakage test, E. faecalis dentin infection was present in a high percentage of the root canals after 120 days of root filling exposure to the bacteria. Tagger`s hybrid technique presented greater quantity of bacteria in histologic sections than root canals obturated with the other techniques. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: 788-794)