Investigation of the marginal adaptation of root-end filling materials in root-end cavities prepared with ultrasonic tips.

AIM: To compare the surface topography of root apices following ultrasonic root-end preparation, and again after root-end fillings submitted to three different finishing techniques. METHODOLOGY: Eighty-one root-end cavities prepared ultrasonically in human canines, were divided at random into three test groups of 27 each. The cavities were filled with Super-EBA, IRM, or ProRoot-MTA and finished by ball burnishing. Eighteen roots from each group received a final finish with either a 30-fluted tungsten carbide finishing bur, or a Zekrya carbide 28 mm bur after storage in water at 37 degrees C for 24 h. The root-end surface topographies were reproduced by means of polyvinylsiloxane impressions and epoxy resin replicas. Scanning electron micrography (SEM) images of each replica were taken prior to and after root-end filling. An image analysis system was used to compare the alteration of the marginal chipping areas and to calculate the gaps located in the dentine/root-end filling interface. RESULTS: When a bur was used to finish the set materials, a significant (P < 0.05) area of marginal chipping was eliminated. The finishing technique did not significantly (P > 0.05) affect the incidence of gaps in groups root-end filled with MTA or IRM. Super-EBA and IRM retrofillings finished with a ball burnisher or a Zekrya bur displayed a significantly (P < 0.05) larger calculated gap area than roots filled with MTA. CONCLUSION: Under this in vitro study, the marginal adaptation of MTA was good with or without finishing procedures. Applying a finishing bur over the condensed and set IRM and Super-EBA created better marginal adaptation.

Evidence for the presence of a type III secretion system in diffusely adhering Escherichia coli (DAEC).

Diffusely adhering Escherichia coli (E. coli) strains (DAEC) represent a potential cause of diarrhoea in infants, and the detection of type three secretion system (TTSS) genes in DAEC would substantiate their pathogenic nature. In this work, four isolates of DAEC, recovered from stools of diarrhoeic children, were analysed by PCR, in order to detect the presence of TTSS genes. Primers targeted to the escC, escJ, escN and escV, some of the most conserved TTSS genes in enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC), were used in order to verify the occurrence of homologous genes in our DAEC isolates. By this approach, we were able to characterise DNA fragments corresponding to putative escJ and escN genes in all DAEC isolates. Furthermore, DNA fragments homologous to the escC and escV genes were also amplified from all isolates. Besides the similarity found among the DAEC esc homologues with EPEC and EHEC esc genes, the nucleotide sequence analysis of the flanking regions of the amplified DNA fragments suggests that the putative DAEC esc genes are organised in the same manner as observed in EPEC and in EHEC strains. The results described here provide strong evidence for the presence of a TTSS in the DAEC strains analysed, implicating a pathogenic nature of these isolates.

Exogenous vasopressin influences intraocular pressure via the V(1) receptors.

PURPOSE: To compare central, peripheral, and ocular effects of exogenously given vasopressin on intraocular pressure (IOP) and to identify the related receptor mechanisms of action in rabbits. METHODS: Young adult New Zealand albino rabbits were entrained under a daily 12-hour light and 12-hour dark cycle. In the early light period, bolus injections of vasopressin or desmopressin (a specific V(2) receptor agonist) were given either to the central nervous system (CNS) through an implanted cannula to the 3(rd) ventricle or to the systemic circulation via the ear vein in conscious rabbits. Changes in IOP and pupil size were monitored for up to 6 hours and dose-response curves were generated. Effects of centrally and peripherally given vasopressin on IOP were further examined following pretreatments with a selective V(1) receptor antagonist administered into the 3(rd) ventricle and into the ear vein, respectively. In order to clarify whether or not exogenously given vasopressin can alter IOP by mechanisms inside the eye, vasopressin was injected into the anterior chamber or the vitreous chamber unilaterally in conscious rabbits. Changes in IOP and pupil size were monitored. After an anterior chamber or intravitreal injection of the V(1) receptor antagonist, changes in IOP and pupil size due to an intravenous injection of vasopressin were determined to study the involvement of the related receptor mechanism. RESULTS: A dose-dependent elevation of IOP appeared after injections of vasopressin into the 3(rd) ventricle. There was no pupillary change. This IOP elevation was blocked by the pretreatment with the V(1) receptor antagonist. Following intravenous injections of vasopressin, significant reductions of IOP and pupil size occurred. These reductions were blocked by the pretreatment with the V(1) receptor antagonist. Intracerebroventricular or intravenous injection of desmopressin had no effect on IOP or pupil size. Injection of vasopressin into the anterior chamber or the vitreous chamber caused significant reductions of IOP and pupil size. Pretreatment with the V(1) receptor antagonist into the anterior chamber or the vitreous chamber prevented the reductions of IOP and pupil size following an intravenous injection of vasopressin. CONCLUSIONS: Intracerebroventricular and intravenous injections of vasopressin cause opposite effects on IOP. The central effect of vasopressin on IOP and the peripheral effects of vasopressin on IOP and pupil size are due to stimulations of the V(1) receptors. Reductions of IOP and pupil size following intravenous injections of vasopressin are at least partially due to stimulations of the V(1) receptors inside the eye.

Ocular health myths among a hospital staff.

In order to evaluate their common beliefs in the field of ocular health, an exploratory survey was carried out among 122 professionals belonging to different ranks and specialty areas of the University of Campinas Clinical Hospital (UNICAMP-CH), São Paulo, Brazil. The non-structured questionnaire used asked about common ophthalmologic problems as well as the presence of popular myths about ocular health, such as: 'cure' of visual problems by the use of glasses; reading under insufficient lighting or watching TV too much close to the apparatus is harmful; consequences from the intensive use of the eyes; or special food being needed for better vision. The results indicated the existence of various misconceptions, even among health professionals, such as: belief in the cure of refractive problems by the use of glasses (40.0%); or damage to vision due to insufficient lighting, watching TV too much close to the apparatus or from the intensive use of the eyes (86.7%). Among the professionals performing activities within the ophthalmology department, 62.5% admitted believing in visual damage as a result of conditions such as those mentioned above and 37.5% stated that reading in a moving vehicle is detrimental to vision. From these data, one is entitled to conclude that misconceptions continue to be present, even among professionals in the health area; this indicates that educational programs in ocular health should be provided, especially for individuals working within a hospital ophthalmological service.