Comparison of Fourier-Domain and Time-Domain Optical Coherence Tomography in the Detection of Band Atrophy of the Optic Nerve

PURPOSE: To compare the ability of Fourier-domain (FD) optical coherence tomography (3D OCT-1000; Top, con, Tokyo, Japan) and time domain (TD) OCT (Stratus; Carl Zeiss Meditec Inc, Dublin, California, USA) to detect axonal loss in eyes with band atrophy (BA) of the optic nerve. DESIGN: Cross-sectional study. METHODS: Thirty-six eyes from 36 patients with BA and temporal visual field (VF) defect from chiasmal compression and 36 normal eyes were studied. Subjects were submitted to standard automated perimetry and macular and retinal nerve fiber layer (RNFL) measurements were taken using 3D OCT-1000 and Stratus OCT. Receiver operating characteristic (ROC) curves were calculated for each parameter. Spearman correlation coefficients were obtained to evaluate the relationship between RNFL and macular thickness parameters and severity of VF loss. Measurements from the two devices were compared. RESULTS: Regardless of OCT device, all RNFL and macular thickness parameters were significantly lower in eyes with BA compared with normal eyes, but no statistically significant difference was found with regard to the area under the ROC curve. Structure-function relationships were also similar for the two devices. In both groups, RNFL and macular thickness measurements were generally and in some cases significantly smaller with 3D OCT-1000 than with Stratus OCT. CONCLUSIONS: The introduction of FD technology did not lead to better discrimination ability for detecting BA of the optic nerve compared with TD technology when using the software currently provided by the manufacturer. 3D OCT-1000 FD OCT RNFL and macular measurements were generally smaller than TD Stratus OCT measurements. Investigators should be aware of this fact when comparing measurements obtained with these two devices. (Am J Oplathalmol 2009;147: 56-63. (c) 2009 by Elsevier Inc. All rights reserved.)

Comparison of the GDx VCC scanning laser polarimeter and the stratus optical coherence tomograph in the detection of band atrophy of the optic nerve

Aim To compare the ability of scanning laser polarimeter (SLP) with variable corneal compensation (GDx VCC) and optical coherence tomograph (Stratus OCT) to discriminate between eyes with band atrophy (BA) of the optic nerve and healthy eyes. Methods The study included 37 eyes with BA and temporal visual field (VF) defects from chiasmal compression, and 29 normal eyes. Subjects underwent standard automated perimetry (SAP) and retinal nerve fibre layer (RNFL) scans using GDx VCC and Stratus OCT. The severity of the VF defects was evaluated by the temporal mean defect (TMD), calculated as the average of 22 values of the temporal total deviation plot on SAP. Receiver operating characteristic (ROC) curves were calculated. Pearson`s correlation coefficients were used to evaluate the relationship between RNFL thickness parameters and the TMD. Results No significant difference was found between the ROC curves areas (AUCs) for the GDx VCC and Stratus OCT with regard to average RNFL thickness (0.98 and 0.99, respectively) and the superior (0.94; 0.95), inferior (0.96; 0.97), and nasal (0.92; 0.96) quadrants. However, the AUC in the temporal quadrant (0.77) was significantly smaller (P < 0.001) with GDx VCC than with Stratus OCT (0.98). Lower TMD values were associated with smaller RNFL thickness in most parameters from both equipments. Conclusion Adding VCC resulted in improved performance in SLP when evaluating eyes with BA, and both technologies are sensitive in detecting average, superior, inferior, and nasal quadrant RNFL loss. However, GDx VCC still poorly discriminates RNFL loss in the temporal quadrant when compared with Stratus OCT.

Dual candidemia detected by nested polymerase chain reaction in two critically ill children

The use of improved microbiological procedures associated with molecular techniques has increased the identification of Candida bloodstream infections, even if the isolation of more than one species by culture methods remains uncommon. We report the cases of two children presenting with severe gastrointestinal disorders and other risk factors that contribute to Candida infections. In the first patient, C. albicans DNA was initially detected by a nested-amplification and C. tropicalis was found later during hospitalization, while blood cultures were persistently negative. In the second child, there was amplification of C. albicans and C. glabrata DNA in the same samples, but blood cultures yielded only C. albicans. Both patients received antifungal therapy but had unfavorable outcomes. These two cases illustrate that PCR was more successful than culture methods in detecting Candida in the bloodstream of high risk children, and was also able to detect the presence of more than one species in the same patient that might impact therapy when the fungi are resistant to azole compounds.

Inhibition of phospholipase A(2) in rat brain decreases the levels of total Tau protein

The microtubule-associated protein Tau promotes the assembly and stability of microtubules in neuronal cells. Six Tau isoforms are expressed in adult human brain. All six isoforms become abnormally hyperphosphorylated and form neurofibrillary tangles in Alzheimer disease (AD) brains. In AD, reduced activity of phospholipase A(2) (PLA(2)), specifically of calcium-dependent cytosolic PLA(2) (cPLA(2)) and calcium-independent intracellular PLA(2) (iPLA(2)), was reported in the cerebral cortex and hippocampus, which positively correlated with the density of neurofibrillary tangles. We previously demonstrated that treatment of cultured neurons with a dual cPLA(2) and iPLA(2) inhibitor, methyl arachidonyl fluorophosphonate (MAFP), decreased total Tau levels and increased Tau phosphorylation at Ser(214) site. The aim of this study was to conduct a preliminary investigation into the effects of in vivo infusion of MAFP into rat brain on PLA(2) activity and total Tau levels in the postmortem frontal cortex and dorsal hippocampus. PLA(2) activity was measured by radioenzymatic assay and Tau levels were determined by Western blotting using the anti-Tau 6 isoforms antibody. MAFP significantly inhibited PLA(2) activity in the frontal cortex and hippocampus. The reactivity to the antibody revealed three Tau protein bands with apparent molecular weight of close to 40, 43 and 46 kDa in both brain areas. MAFP decreased the 46 kDa band intensity in the frontal cortex, and the 43 and 46 kDa band intensities in the hippocampus. The results indicate that in vivo PLA(2) inhibition in rat brain decreases the levels of total (nonphosphorylated plus phosphorylated) Tau protein and corroborate our previous in vitro findings.

Gamma band oscillations under influence of bromazepam during a sensorimotor integration task: An EEG coherence study

The goal of the present study was to explore the dynamics of the gamma band using the coherence of the quantitative electroencephalography (qEEG) in a sensorimotor integration task and the influence of the neuromodulator bromazepam on the band behavior. Our hypothesis is that the needs of the typewriting task will demand the coupling of different brain areas, and that the gamma band will promote the binding of information. It is also expected that the neuromodulator will modify this coupling. The sample was composed of 39 healthy subjects. We used a randomized double-blind design and divided subjects into three groups: placebo (n = 13), bromazepam 3 mg (n = 13) and bromazepam 6 mg (n = 13). The two-way ANOVA analysis demonstrated a main effect for the factors condition (i.e., C4-CZ electrode pair) and moment (i.e., C3-CZ, C3-C4 and C4-CZ pairs of electrodes). We propose that the gamma band plays an important role in the binding among several brain areas in complex motor tasks and that each hemisphere is influenced in a different manner by the neuromodulator. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Scanning laser polarimetry with enhanced corneal compensation for detection of axonal loss in band atrophy of the optic nerve

PURPOSE: To compare the abilities of scanning laser polarimetry (SLP) with enhanced corneal compensation (ECC) and variable corneal compensation (VCC) modes for detection of retinal nerve fiber layer (RNFL) loss in eyes with band atrophy (BA) of the optic nerve. DESIGN. Cross-sectional study. METHODS: Thirty-seven eyes from 37 patients with BA and temporal visual field defect from chiasmal compression and 40 eyes from 40 healthy subjects were studied. Subjects underwent standard automated perimetry and RNFL measurements using an SLP device equipped with VCC and ECC. Receiver operating characteristic (ROC) curves were calculated for each parameter. Pearson correlation coefficients were obtained to evaluate the relationship between RNFL thickness parameters and severity of visual field loss, as assessed by the temporal mean defect. RESULTS: All RNFL thickness parameters were significantly lower in eyes with BA compared with normal eyes with both compensation modes. However, no statistically significant differences were observed in the areas under the ROC curves for the different parameters between GDx VCC and ECC (Carl Zeiss Meditec, Inc, Dublin, California, USA). Structure-function relationships also were similar for both compensation modes. CONCLUSIONS: No significant differences were found between the diagnostic accuracy of GDx ECC and that of VCC for detection of BA of the optic nerve. The use of GDx ECC does not seem to provide a better evaluation of RNFL loss on the temporal and nasal sectors of the peripapillary retina in subjects with BA of the optic nerve.

Tension band wire fixation for valgus osteotomies of the proximal femur: A biomechanical study of three configurations of fixation

Background. A variety of techniques can be used to achieve stabilization of femoral valgus osteotomies in children, but what is lacking is a versatile fixation system that associates stability and versatility at different ages and for different degrees of deformity. Methods. Mechanical tests of three configurations used to fix femoral valgus osteotomies, based oil the tension band wire principle, were carried out. A 30 degrees wedge valgus osteotomy was performed at the subtrochanteric level in 60 swine femurs and fixed with three different systems. In Group 1, two Kirschner wires (K wire) were introduced from the tip of the greater trochanter to the medial cortex, crossing the osteotomy. A flexible steel wire was anchored to the K wires into holes in the lateral cortex and tightened to form a tension band. The same setup was used in Group 2, but two additional smooth K wires were inserted into the lateral surface of the greater trochanter and driven to the femoral head with the distal extremities bent and tied around tile bone shaft. In Group 3, the fixation was similar to that in Group 2, but tile ascending K wires were introduced below the osteotomy level, crossing the osteotonly. Mechanical tests in bending-compression and torsion were used to access the stability. Findings. The torsional relative stiffness was 116% greater for Group 3 (0.27 N m/degree) and no significant difference was found between Group 1 (0.10 N m/degree) and Group 2 (0.12 N m/degree). The average torque was 103% higher for Group 3 (1.86 N m). Stiffness in bending-compression was significantly higher in Group 3 (508 x 10(3) N/m) than in Group 1 (211 x 10(3) N/m) and Group 2 (219 x 10(3) N/m). Interpretation. Fixation as used in Group 3 was significantly more stable, both in torsion and bending-compression tests, than tile other two techniques. (c) 2007 Elsevier Ltd. All rights reserved.

Body composition assessment of undernourished older subjects by dual-energy x-ray absorptiometry and bioelectric impedance analysis

The prevention and treatment of diseases related to changes in body composition require accurate methods for the measurement of body composition. However, few studies have dealt specifically with the assessment of body composition of undernourished older subjects by different methodologies. To assess the body composition of undernourished older subjects by two different methods, dual energy x-ray absorptiometry (DXA) and bioelectric impedance (BIA), and to compare results with those of an eutrophic group. The study model was cross-sectional; the study was performed at the University Hospital of the School of Medicine of Ribeiro Preto, University of So Paulo, Brazil. Forty-one male volunteers aged 62 to 91 years. The groups were selected on the basis of anamnesis, physical examination and nutritional assessment according to the Mini Nutritional Assessment (MNA) score. Body composition was assessed by DXA and BIA. Body weight, arm and calf circumference, body mass index (BMI), fat free mass (FFM) and fat mass (FM) were significantly lower in the undernourished group as compared to the eutrophic group. There were no significant differences between FFM and FM mean values determined by DXA and BIA in both groups, but the agreement between methods in the undernourished group was less strong. Our results suggest caution when BIA is to be applied in studies including undernourished older subjects. This study does not support BIA as an accurate method for the individual assessment of body composition.

Bacterial colonization in hemodialysis temporary dual lumen catheters: A prospective study

Aims. The use of hemodialysis temporary dual-lumen catheters is often complicated by infections, which may be a significant cause of death among patients with end stage renal disease (ESRD). The aim of this study was to assess the incidence of bacteremia and bacterial colonization related to non-tunneled, non-cuffed, dual-lumen temporary catheters in patients with ESRD submitted to hemodialysis. Methods. This study included 29 patients with ESRD. After catheter implantation, patients were monitored throughout the period of catheter permanence by means of blood samples collected weekly from a peripheral vein. Bacteria were isolated and identified according to CLSI recommendations. When catheters were removed for any reason, their tips were evaluated microbiologically. Results. A total of 194 blood samples from the 29 patients implanted with 55 catheters were analyzed. Of these, 15.5% (30 samples) demonstrated bacterial growth, principally Staphylococcus epidermidis (64.5%). Twenty patients (68.9%) presented at least one positive blood culture during follow-up. The median time for catheter colonization was 18.5 days (95% CI: 16.8-30.3). Of the 55 catheters implanted, 28 (50.9%) showed bacterial colonization, corresponding to 23.4 episodes/1000 catheter/days and 9.2 episodes of bacteremia /1000 catheter/days. Fifteen of 28 catheter tips analyzed showed bacterial growth (53.5%). In 14 of these (93.3%), there was agreement between the isolates from the catheter tip and blood cultures. Of 24 episodes of positive blood cultures from 20 different patients in 17 episodes (70.8%), the patients showed no clinical signs or symptoms of bacteremia. Conclusions. The high incidence of catheter colonization, the correlation between blood and catheter tip cultures, and the occurrence of frequent cases of asymptomatic bacteremia justify the proposal of routine peripheral blood collections to monitor patients undergoing hemodialysis with temporary dual-lumen catheters.

The diagonal band of Broca is involved in the pressor pathway activated by noradrenaline microinjected into the periaqueductal gray area of rats

Aims: The dorsal periaqueductal gray area (dPAG) is involved in cardiovascular modulation. Previously, we reported that noradrenaline (NA) microinjection into the dPAG caused a pressor response that was mediated by vasopressin release into the circulation. However, the neuronal pathway that mediates this response is as yet unknown. There is evidence that chemical stimulation of the diagonal band of Broca (dbB) also causes a pressor response mediated by systemic vasopressin release. In the present study, we evaluated the participation of the dbB in the pressor response caused by NA microinjection into the dPAG as well as the existence of neural connections between these areas. Main methods: With the above goal, we verified the effect of the pharmacological ablation of the dbB on the cardiovascular response to NA microinjection into the dPAG of unanesthetized rats. In addition, we microinjected the neuronal tracer biotinylated-dextran-amine (BDA) into the dPAG and looked for efferent projections from the dPAG to the dbB. Key findings: The pharmacologically reversible ablation of the dbB with local microinjection of CoCl(2) significantly reduced the pressor response caused by NA microinjection (15 nmol/50 nL) into the dPAG. In addition, BDA microinjection into the dPAG labeled axons in the dbB, pointing to the existence of direct connections between these areas. Significance: The present results indicate that synapses within the dbB are involved in the pressor pathway activated by NA microinjection into the VAG and direct neural projection from the dPAG to the dbB may constitute the neuroanatomic substrate for this pressor pathway. (C) 2009 Elsevier Inc. All rights reserved.

Diagonal band of Broca modulates the cardiac component of the baroreflex in unanesthetized rats

The diagonal band of Broca (DBB) is involved in cardiovascular control in rats, In the present Study, we report the effect of acute and reversible neurotransmission inhibition in the DBB by bilateral microinjection of the nonselective neurotransmission blocker CoCl(2) (1 mM, 100 nL) on the cardiac baroreflex response in unanesthetized rats. Local DBB neurotransmission inhibition did not affect baseline values of either blood pressure or heart rate, Suggesting no tonic DBB influence oil cardiovascular system activity. However, CoCl(2) microinjections enhanced both the reflex bradycardia associated with blood pressure increases caused by i.v. infusion of phenylephrine and tachycardiac response evoked by blood pressure decreases caused by i.v. infusion of sodium nitroprusside. An increase in baroreflex gain was also observed. Baroreflex returned to control values 60 min after CoCl(2) microinjections, confirming its reversible effect. In conclusion, our data suggest that synapses within DBB have a tonic inhibitory influence on both the cardiac parasympathetic and sympathetic components of the baroreflex. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

Dual role of hydrogen sulfide in mechanical inflammatory hypernociception

Hydrogen Sulfide (H2S) is an endogenous gas involved in several biological functions, including modulation of nociception. However, the mechanisms involved in such modulation are not fully elucidated. The present Study demonstrated that the pretreatment of mice with PAG, a H2S synthesis inhibitor, reduced LPS-induced mechanical paw hypernociception. This inhibition of hypernociception was associated with the prevention of neutrophil recruitment to the plantar tissue. Conversely, PAG had no effect on LPS-induced production of the hypernociceptive cytokines, TNF-alpha, IL-1 beta and CXCL1/KC and on hypernociception induced by PGE(2), a directly acting hypernociceptive mediator. In contrast with the pro-nociceptive role of endogenous H2S. systemic administration of NaHS, a H2S donor, reduced LPS-induced mechanical hypernociception in mice. Moreover, this treatment inhibited mechanical hypernociception induced by PGE(2), suggesting a direct effect of H2S on nociceptive neurons. The antinociceptive mechanism of exogenous H2S depends on K-(ATP)(+) channels since the inhibition of PGE(2) hypernociception by NaHS was prevented by glibenclamide (K-(ATP)(+) channel blocker). Finally, NaHS did not alter the thermal nociceptive threshold in the hot-plate test, confirming that its effect is mainly peripheral. Taken together, these results suggest that H2S has a dual role in inflammatory hypernociception: 1. an endogenous pro-nociceptive effect due to up-regulation of neutrophil migration. and 2. an antinociceptive effect by direct blockade of nociceptor sensitization modulating K-(ATP)(+) channels. (c) 2008 Elsevier B.V. All rights reserved.

Dual Effects of Hyperprolactinemia on Carrageenan-Induced Inflammatory Paw Edema in Rats

Objectives: The effects of short-term 5-day and long-term 30-day hyperprolactinemia induced by domperidone (1.7 mg/kg/day, s.c.) or ectopic pituitary graft on the acute inflammatory response induced by carrageenan were evaluated in male rats. Both models of hyperprolactinemia effectively increased serum prolactin (PRL) levels. Methods: The volume in milliliters of inflammatory edema was measured by plethysnnography 1, 2, 3, 4, 6, 8 and 24 h after carrageenan injection. The areas under the inflammatory time-response curves were compared. Additionally, the effects of hyperprolactinemia on body weight and serum corticosterone levels were evaluated. Results: In both domperidone-treated and pituitary graft-implanted animals, short-term 5-day hyperprolactinemia increased the inflammatory response, while long-term 30-day hyperprolactinemia had anti-inflammatory effects. Body weight was not affected by either short- or long-term hyperprolactinennia. Conclusion: These results show that PRL has biphasic effects on the carrageenan-induced inflammatory response. Copyright (C) 2011 S. Karger AG, Basel

Dual origin of mesenchymal stem cells contributing to organ growth and repair

In many adult tissues, mesenchymal stem cells (MSCs) are closely associated with perivascular niches and coexpress many markers in common with pericytes. The ability of pericytes to act as MSCs, however, remains controversial. By using genetic lineage tracing, we show that some pericytes differentiate into specialized tooth mesenchyme-derived cells-odontoblasts-during tooth growth and in response to damage in vivo. As the pericyte-derived mesenchymal cell contribution to odontoblast differentiation does not account for all cell differentiation, we identify an additional source of cells with MSC-like properties that are stimulated to migrate toward areas of tissue damage and differentiate into odontoblasts. Thus, although pericytes are capable of acting as a source of MSCs and differentiating into cells of mesenchymal origin, they do so alongside other MSCs of a nonpericyte origin. This study identifies a dual origin of MSCs in a single tissue and suggests that the pericyte contribution to MSC-derived mesenchymal cells in any given tissue is variable and possibly dependent on the extent of the vascularity.

Effect of curing protocol on the polymerization of dual-cured resin cements

Objectives. The purpose of this study was to evaluate how curing protocol affects the extent of polymerization of dual-cured resin cements. Methods. Four commercial resin cements were used (DuoLink, Panavia F 2.0, Variolink II and Enforce). The extent of polymerization of the resin cements cured under different conditions was measured using a (1)H Stray-Field MRI method, which also enabled to probe molecular mobility in the kHz frequency range. Results. Resin cements show well distinct behaviours concerning chemical cure. Immediate photo-activation appears to be the best choice for higher filler loaded resin cements (Panavia F 2.0 and Variolink). A photo-activation delay (5 min) did not induce any significant difference in the extent of polymerization of all cements. Significance. The extent of polymerization of dual-cured resin cements considerably changed among products under various curing protocols. Clinicians should optimize the materials choice taking into account the curing characteristics of the cements. (C) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.