1,944 research outputs found
Impaired placental perfusion and major fetal cardiac defects
Objectives: To investigate the relationship between fetal congenital heart defects (CHD) and placental perfusion assessed by uterine artery pulsatility index (UtA-PI) in relation to development of preeclampsia (PE).
Methods: This was a prospective screening study in singleton pregnancies at 19-24 weeksâ gestation. Transvaginal ultrasound was used to measure the UtA-PI and the values were converted into multiples of the normal median (MoM). Median MoM values in pregnancies with fetuses with isolated major CHD were compared to those without CHD in relation to development of PE.
Results: The 91,407 singleton pregnancies fulfilling the entry criteria included 206 (0.23%) with isolated major fetal CHD and 91,201 without CHD. The prevalence of PE was 4.4% in those with CHD and 2.7% in those without CHD (RR 1.6, 95% CI 0.84-3.04; p=0.150); the respective values for preterm-PE, with delivery at <37 weeksâ gestation, were 2.4% and 0.7%, (RR 3.4, 95% CI 1.42-8.09; p=0.006). In the total population, the median UtA-PI MoM was significantly higher in those that developed PE compared to those without PE (1.22, IQR 0.94-1.57 vs. 1.00, IQR 0.84-1.19; p<0.0001) and in the PE group the median UtA-PI MoM was inversely related to gestational age at delivery (r=-0.458; p<0.0001). The same pattern of inverse relationship between UtA-PI MoM and gestational age at delivery with PE was observed in pregnancies with and without CHD, but in the CHD group, compared to those without CHD, UtA-PI was significantly higher both in pregnancies with and in those without
PE.
Conclusions: In both pregnancies with and without fetal CHD that develop PE impedance to flow in the uterine arteries is increased and this increase is particularly marked in those with preterm-PE. The prevalence of preterm-PE is more than 3 times higher in pregnancies with than without fetal major CHD and the prevalence of major CHD in pregnancies with preterm-PE is also more than 3 times higher than in those without PE. However, >97% of pregnancies with fetal CHD do not develop preterm-PE and >99% of pregnancies with preterm-PE are not associated with fetal CHD
One-step determination of total iron using deferiprone or kojic acid as colorimetric reagents
The role of iron, one of the most common metals in the environment, is fundamental in many biological and geochemical processes, which determine its availability in the two main oxidation states Fe2+ and Fe3+. Its relevance in the environment, industrial applications, and human physiology, as well as in many other fields has constantly encouraged the development of analytical techniques for its accurate determination. Spectrophotometric methods are those most frequently applied for iron determination in real samples, with specific reagents for the two existing oxidation state right now. In the present work, two low-cost, non-toxic, colorimetric reagents are proposed: deferiprone and kojic acid. These compounds present peculiar features, in particular the formation of 1:3 complexes with Fe3+ of extremely high stability and absorptivity in a wide operative pH range. In this study, we show that both reagents can be used to measure the total iron content. Actually, the extremely low redox potential characterizing the FeL3 complexes permits to determine the total concentration of iron independently from the starting oxidation state, and assures the complete oxidation in presence of oxygen of any amount of Fe2+ to Fe3+ complexes. These features constitute a novelty in the analytical determination of total iron not requiring any pretreatment of the sample, contrary to the methods in use, devoted either to Fe3+ or to Fe2+, necessitating awkward and error generating oxidative or reductive processes. The analytical performance of the proposed spectrophotometric method has been evaluated for the full compliance with the Lambert-Beer law, the operative range of iron concentration, the influence of pH, and the interfering effects of other metal ions. Finally, it has been validated in terms of LoD, LoQ, linearity, precision, and trueness, and has been tested on total iron determination in natural water certified material and in two biological reference materials, human urine and serum
Fetal major cardiac defects and placental dysfunction at 11-13 weeks' gestation
Objectives: To investigate the relationship between fetal major cardiac defects and markers of placental perfusion and function.
Methods: This was a prospective screening study in singleton pregnancies at 11-13 weeksâ gestation. Uterine artery pulsatility index (UTPI), serum pregnancy associated plasma protein-A (PAPP-A) and placental growth factor (PLGF) were measured and the values were converted into multiples of the normal median (MoM). Median MoM values in fetuses with isolated major cardiac defects were compared to those in fetuses without major defects.
Results: The 50,094 singleton pregnancies fulfilling the entry criteria included 49,898 pregnancies with a normal cardiac anatomy and 196 (0.39%) with major congenital cardiac defects; 73 (37.2%) with conotruncal defects, 63 (32.1%) with left ventricular outflow tract (LVOT) defects and 60 (30.6%) with valvular defects. In the group of cardiac defects, compared to controls, there was lower median PAPP-A MoM (0.81 vs 1.00, p<0.0001) and PLGF MoM (0.78 vs 1.00, p<0.0001) but no significant difference in UTPI MoM (1.01 vs 1.00, p=0.162).
Conclusions: In pregnancies with isolated major cardiac defects there is evidence of placental dysfunction in the absence of impaired placental perfusion
Laryngeal myxoma: a case report and review of the literature
Myxomas are a rare benign neoplasm of uncertain mesenchymal cell origin, typically involving the heart. Laryngeal myxomas are uncommon, and are usually misdiagnosed as laryngeal polyp. To the best of our knowledge, there are only nine reported cases in the English literature. We report a case of a laryngeal myxoma presenting clinically as a left vocal cord polyp in a 77 year old male, and review the literature related to this rare entity
Double-Tuned Birdcage Radio Frequency Coil for 7 T MRI: Optimization, Construction and Workbench Validation
The aim of the present study is the optimization, construction, and workbench validation of a double-tuned 1H- 23Na volume radio frequency (RF) coil suitable for human head imaging at
7 T, based on the birdcage geometry. The birdcage-like design which is considered is the four-ring model, in which two standard birdcage-like structures with the same diameters are nested along the longitudinal axis. Simulations based on Maxwellâs equations are performed to evaluate the RF magnetic field homogeneity and the RF coil efficiency varying the coil geometrical parameters. The RF magnetic field homogeneity is evaluated both on the transverse (z = 0) and longitudinal (y = 0) planes without performing the impedance matching procedure, so that the RF coil symmetry is not perturbed by the matching network. The RF coil efficiency is instead dependent on the effective coil input RF power, and it is evaluated after matching the coil, so that the reflected power is minimized, assuming that the stimulation power is totally delivered to the RF coil. Considering the simulation results and the target application, the useful RF coil geometrical parameters are fixed. The four-ring model, which showed the best performances, has been built and tested on a workbench, using a cylindrical phantom filled with a 0.05 M saline solution as load. This provides the first example of a four-ring realization intended 1H- 23Na for human head imaging at 7 T
Clinically aggressive central giant cell granulomas in two patients with neurofibromatosis 1
Background
Neurofibromatosis 1 (NF1) is an autosomal dominantly inherited disorder caused by a spectrum of mutations affecting the Nf1 gene. Affected patients develop benign and malignant tumors at an increased frequency. Clinical findings include multiple cutaneous café-au-lait pigmentations, neurofibromas, axillary freckling, optic gliomas, benign iris hamartomas (Lisch nodules), scoliosis, and poorly defined soft tissue lesions of the skeleton. Kerl first reported an association of NF1 with multiple central giant cell granulomas (CGCGs) of the jaws. There have since been 4 additional published cases of NF1 patients with CGCGs of the jaws.
Clinical cases
We report on 2 patients who presented with NF1 and aggressive CGCGs of the jaws. In both cases, the clinical course was characterized by numerous recurrences despite mechanical curettage and surgical resection.
Conclusions
We review proposed mechanisms to explain the apparent association between NF1 and an increased incidence of CGCGs of the jaws. While the presence of CGCGs of the jaws in patients with NF1 could represent either a coincidental association or a true genetic linkage, we propose that this phenomenon is most likely related to NF1-mediated osseous dysplasia. Compared to normal bone, the Nf1-haploinsufficient bone in a patient with NF1 may be less able to remodel in response to as of yet unidentified stimuli (e.g. excessive mechanical stress and/or vascular fragility), and consequently may be more susceptible to developing CGCG-like lesions. Alternatively, the CGCG in NF1 patients could represent a true neoplasm, resulting from additional, as of yet unidentified, genetic alterations to Nf1-haploinsufficient bone
A family of kojic acid derivatives aimed to remediation of Pb2+ and Cd2+
The present work analyzes the complex formation ability towards Pb2+ and Cd2+ of a series of kojic acid derivatives that join the chelating properties of the pyrone molecules and those of polyamines, with the aim of evaluating how the different effects of oxygen and nitrogen coordinating groups act on the stability of metal complexes. Experimental research is carried out using potentiometric and spectrophotometric techniques supported by 1H and 13C NMR spectroscopy and DFT calculations. Actually, a different coordination mechanism toward Pb2+ and Cd2+ was proved: in the case of Pb2+, coordination takes place exclusively via the oxygen atoms, while the contribute of the nitrogen atoms appears relevant in the case of Cd2+. Lead complexes of all the studied ligands are characterized by significantly stronger stability than those of cadmium. Finally, on the basis of the measured complex formation stabilities, some of the proposed molecules seems promising effective ligands for lead and cadmium ion decorporation from polluted soils or waste waters
As(III, V) Uptake from Nanostructured Iron Oxides and Oxyhydroxides: The Complex Interplay between Sorbent Surface Chemistry and Arsenic Equilibria
Iron oxides/oxyhydroxides, namely maghemite, iron oxide-silica composite, akaganeite, and ferrihydrite, are studied for AsV and AsIII removal from water in the pH range 2â8. All sorbents were characterized for their structural, morphological, textural, and surface charge properties. The same experimental conditions for the batch tests permitted a direct comparison among the sorbents, particularly between the oxyhydroxides, known to be among the most promising As-removers but hardly compared in the literature. The tests revealed akaganeite to perform better in the whole pH range for AsV (max 89 mg gâ1 at pH0 3) but to be also efficient toward AsIII (max 91 mg gâ1 at pH0 3â 8), for which the best sorbent was ferrihydrite (max 144 mg gâ1 at pH0 8). Moreover, the study of the sorbentsâ surface chemistry under contact with arsenic and arsenic-free solutions allowed the understanding of its role in the arsenic uptake through electrophoretic light scattering and pH measurements. Indeed, the sorbentâs ability to modify the starting pH was a crucial step in determining the removal of performances. The AsV initial concentration, contact time, ionic strength, and presence of competitors were also studied for akaganeite, the most promising remover, at pH0 3 and 8 to deepen the uptake mechanism
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