102 resultados para Posterior cingulate cortex
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
70 human temporal bones were analyzed with the aid of an otologic microscope. The styloid prominence was found to be extremely variable in shape, location and occurrence. Depending on the degree of development, the prominence establishes important relationships with the sinus tympani, with the fossula of the cochlear fenestra, and with the suprapyramidal recess. Serial sections were used to study the relationship of the styloid process with the facial nerve inside the bony mass of the mastoid portion of the temporal bone.
Resumo:
Many experiments have been performed to evaluate the physiological role of catecholaminergic mechanisms of gonadotropin release. The purpose of the present study was to determine the concentration of β-adrenoreceptors in the remaining (right) cerebral cortex and in right and left hypothalamic halves of hemi-decorticated female rats which exhibited elevated plasma gonadotropin levels as observed previously. The density of β-receptors was measured using a high-affinity β-adrenergic ligand, iodocyanopindolol (ICYP). Scatchard estimates were obtained for maximum binding (B(max) fmol/mg of tissues) from pooled cerebral cortical and hypothalamic tissue of animals under several experimental conditions after hemi-decortication and sham operation. There was an increase in β-adrenoreceptor density in the remaining (right) cerebral cortex at all times examined in hemi-decorticate in comparison with the sham-operated animals (7 days, +10.9%; 21 days, +8.4%; 90 days, +22%; and 90 days plus ovariectomy, +34.8%). The number of β-adrenoreceptors in the right hypothalamic half in hemi-decorticates decreased at 21 days (-42.20%) and then increased at 90 days (+76.63%) and 90 days plus ovariectomy (+51.75%) when compared with the left hypothalamic half. At the same time there were no significant changes in the sham-operated animals when comparing the receptor density in the right and left hypothalamic halves, respectively. Thus, our results suggest a direct adrenergic pathway by which the left cortex can influence the right cortex and a crossed pathway to the contralateral hypothalamus changing adrenergic activity which can alter the β-adrenergic receptor binding capacity in the hypothalamus.
Resumo:
The purpose of this in vivo study was to evaluate the clinical performance of a posterior composite resin TRH (Caulk Dentisply) in class I restorations in primary molars. A total of 30 children aged 5 to 8 years old with 49 class I dental lesions in primary molars participated in the study. The cavity preparations involved removal of carious lesion only and the enamel margins were beveled. The results showed after 30 months that, 82% (32/39) of Alfa ratings and 18% (7/39) of Bravo ratings. We concluded that the composite resin TP-H could be used in conservative restorations in primary molars, particularly in the late mixed dentition.
Resumo:
The NMDA receptor (NMDAR) channel has been proposed to function as a coincidence-detection mechanism for afferent and reentrant signals, supporting conscious perception, learning, and memory formation. In this paper we discuss the genesis of distorted perceptual states induced by subanesthetic doses of ketamine, a well-known NMDA antagonist. NMDAR blockage has been suggested to perturb perceptual processing in sensory cortex, and also to decrease GABAergic inhibition in limbic areas (leading to an increase in dopamine excitability). We propose that perceptual distortions and hallucinations induced by ketamine blocking of NMDARs are generated by alternative signaling pathways, which include increase of excitability in frontal areas, and glutamate binding to AMPA in sensory cortex prompting Ca++ entry through voltage-dependent calcium channels (VDCCs). This mechanism supports the thesis that glutamate binding to AMPA and NMDARs at sensory cortex mediates most normal perception, while binding to AMPA and activating VDCCs mediates some types of altered perceptual states. We suggest that Ca++ metabolic activity in neurons at associative and sensory cortices is an important factor in the generation of both kinds of perceptual consciousness.
Resumo:
Increased GLUT2 gene expression in the renal proximal tubule of diabetic rats is an adaptive condition, which may be important in the diabetic nephropathy development. We investigated the effects of insulin treatment upon the renal GLUT2 overexpression of diabetic rats. Acute treatment, surprisingly, induced a rapid further increase in GLUT2 mRNA content. Twelve hours after insulin injection, GLUT2 mRNA was twice the value of saline-injected rats (P < 0.001), when GLUT2 protein remained unchanged. In response to short-term treatment, both GLUT2 mRNA and protein were increased in 1-day treated rats (P < 0.05 versus saline-injected), decreasing after that, and reaching, within 6 days, values close to those of non-diabetic rats. Concluding, insulin treatment induced: initially, an additional upregulation of GLUT2 gene expression, involving posttranscriptional modulation; thereafter, downregulation of GLUT2 expression, which returns to non-diabetic levels. The former may be related to increased insulin concentration, the latter may be due to glycemic control. © 2005 Elsevier B.V. All rights reserved.
Resumo:
A left paravertebral mass discovered incidentally on routine examination in a 39-year-old woman is described. Computerized tomography studies revealed a 7 × 6 cm, well circumscribed, noncalcified soft tissue mass with lobular borders abutting the left inferior pulmonary vein and descending aorta. It was not possible to determine the exact anatomic location of the mass based on the imaging studies as both peripheral lung tumors and posterior mediastinal lesions may exhibit the imaging findings described here. At thoracotomy, the mass was seen to be well circumscribed, focally attached to the pleura but without involvement of lung parenchyma, and situated in the left posterior mediastinum. On histological examination, the lesion showed the classical features of myxopapillary ependymoma. Immunohistochemical studies confirmed this impression by demonstrating strong positivity of the tumor cells for S-100 protein, glial fibrillary acidic protein, and CD99 and negative staining with other differentiation markers. A review of the literature with a discussion of the histologic and radiologic differential diagnosis of these lesions is presented. © 2006 Elsevier Inc. All rights reserved.
Resumo:
The tractor is one of the machines that more traffics over the soil during the processes involving agricultural production. The interaction tractor/soil is made by the tires which, in most of the cases, are pneumatic. The tire type and the tractor travel speed, interfere directly on the pressure over the soil. One of the techniques employed to evaluate the alterations that tractor traffic causes in the soil is to measure its Cone Index. The aim of this research was to evaluate the same Cone Index alterations caused by an agricultural tractor equipped with both radial tires and bias ply tires, trafficking mobilized soil in four different travel speeds. The experiment was performed in a LATOSSOLO VERMELHO, located 22°51' S, 48°25'W and 770 m of altitude, in Botucatu-SP, Brazil. The soil mobilization was performed with a chisel plow and a disc arrow. The traction was accomplished with a John Deere tractor, model 6600, with 88 kW of power and 6,723 kg. Equipment requiring a force of 25kN was traced by the tractor draw bar. The experimental design was in randomized blocks with 4 × 2 factorial arrangements, with two distinct treatments corresponding to the types of tires (bias and radial) and the four travel speeds, with six replications. There were selected the following speeds: 3.5, 3.9, 5.1 and 5.9 km h-1. To determine the soil resistance, there was utilized MSSU - Mobile Soil Sampling Unit, with which the Cone Index was obtained in layers from 0-100, 100-200, 200-300, 300-400, 400-500 and over 500 mm deep. The Cone Index where evaluated in areas with non contact between tire and soil (ICn) and in the tire footprint track (ICp). There were calculated the Cone Index increments caused by the tractor tire (AIC) and the results showed that as the tractor travel speed increased, there were observed decrements in the medium values of cone index. The radial tire provided smaller values of the Cone Index in the superficial layer of the soil (0 to 100 mm) in relation to the bias ply tire, when the speed was approximately 6 km h-1. The increment in the Cone Index, promoted by the tractor, was more intense in the first 200 mm depth, but it also reached the layer from 200 to 300 mm.
Resumo:
This study proposal was to evaluate the changes at a masticatory muscle temporalis and masseter, through a eletromyographic, at ponters of the right unilateral bite posterior, verifying the difference at the eletric activity between right and left sides. Twenty female volunteers, with ages between 7 and 8 (x = 7.4). The eletromyographics signals were collected in both sides in all volunteers in rest situations and in an usual isotonic mastication, right, left and bilateral and the maximun isometric constriction, which sinal was used to the eletric activity amplitude normalization. The results signed that the right masseter muscle presents an expressive statistic difference, if compared with the left masseter muscle during the left and right mastication, suggesting a right unilateral mastication. The muscle haven't gotten any expressive variance in this amplitude which remained to a proximate flat noticed in a right and habitual mastication, suggesting a right and one sided mastication during the left mastication occurs a raise of the eletric signal amplitude of the muscle left masseter. The right masseter muscle haven't gained any expressive variance, which remained in a proximate flat observed in an usual and right mastication, suggesting a muscular pattern hyperfunction next to the dental crossing.
Resumo:
There are situations which the tomographic exam is done on the affected hip or situations where the contralateral hip presents abnormalities that make it impossible to compare. In this study we aimed to evaluate a tomographic index that does not require comparison between the both hips. Twenty two patients with unilateral acetabular fracture dislocation with fracture of posterior wall were studied. We established the relationship between the remaining posterior wall and the femoral head diameter (head/wall index-H/W index). We evaluated 45 two-dimensional computed tomography scan in normal hips and established the H/W index. In 45 normal hips we simulated a posterior wall fracture with involvement of 25% and 30% of the posterior wall and calculated the H/W index. We divided into five groups with five different H/W index (fractured group with non surgical treatment; fractured group; normal group; normal group with simulated fracture of 25% and; 30% of the posterior wall). 2.4 was the lowest limit of confidence interval of the group with 25% of the posterior wall fracture. When we analyzed the confidence interval of the 30% fracture group the upper limit of the confidence interval was 2.7, close to the lower limit of the surgical group that was 2.9. Thus, we suggest the 2.4 the H/W index limit as an auxiliary criteria to indicate whether or not to operate. H/W index is helpful to decide whether or not surgery indication in the fracture dislocation of the posterior wall of the acetabulum. © 2012 Fujiki et al.; licensee BioMed Central Ltd.
Resumo:
This clinical study assessed the performance of posterior composite resins applied with the Adper™ Single Bond Plus (SB) and Adper ™ Scotchbond SE (SE) adhesive systems and Filtek ™ Supreme Plus composite resin, using modified US Public Health Service criteria. A total of 97 restorations were placed in posterior teeth by two calibrated operators. Application of the materials followed manufacturers' instructions. The restorations were evaluated by two examiners at baseline and after one year. Statistical analyses were conducted using the proportion test at a significance level of 5% (p<0.05). All the restorations evaluated (ie, 100%) received an alpha rating for the criteria of marginal discoloration and marginal integrity at baseline. At one year, for marginal discoloration, 64.6% of SB and 61.2% of SE received an alpha rating. For marginal integrity, 72.9% of SB and 77.6% of SE received an alpha rating. The other restorations received bravo ratings for both criteria. None of the teeth that received the restorative systems presented caries lesions around the restorations. A total of eight teeth presented postoperative sensitivity one week after baseline, five with SB and three with SE; the symptom had disappeared one year later. One year later, composite resin restorations using either adhesive system showed satisfactory clinical performance.
Resumo:
The rehabilitation with oral implants is, without any doubt, a consecrated technique. But often we face situations of high bone atrophy where the conventional installation of dental implants is not possible. The posterior mandible, when severely resorbed, generally requires complex techniques to be rehabilitated with implants, such as the lateralization of the inferior alveolar nerve. As an option for these cases, this paper proposes the use of short implants for the rehabilitation of severely resorbed posterior mandible. Copyright © 2013 by Mutaz B. Habal, MD.
Resumo:
The insular cortex (IC) has been reported to be involved in the modulation of memory and autonomic and defensive responses. However, there is conflicting evidence about the role of the IC in fear conditioning. To explore the IC involvement in both behavioral and autonomic responses induced by contextual fear conditioning, we evaluated the effects of the reversible inhibition of the IC neurotransmission through bilateral microinjections of the non-selective synapse blocker CoCl2 (1 mm) 10 min before or immediately after the conditioning session or 10 min before re-exposure to the aversive context. In the conditioning session, rats were exposed to a footshock chamber (context) and footshocks were used as the unconditioned stimulus. Forty-eight hours later, the animals were re-exposed to the aversive context for 10 min, but no shock was given. Behavioral (freezing) as well as cardiovascular (arterial pressure and heart rate increases) responses induced by re-exposure to the aversive context were analysed. It was observed that the local IC neurotransmission inhibition attenuated freezing and the mean arterial pressure and heart rate increase of the groups that received the CoCl2 either immediately after conditioning or 10 min before re-exposure to the aversive context, but not when the CoCl2 was injected before the conditioning session. These findings suggest the involvement of the IC in the consolidation and expression of contextual aversive memory. However, the IC does not seem to be essential for the acquisition of memory associated with aversive context. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.