Not all pediatric intestinal polyps are alike.

BACKGROUND/AIMS: In childhood, clinical presentation of intes- tinal polyps is variable. Painless rectal red blood loss is the most common presenting sign. Most polyps are sporadic, isolated and benign. However, it is important to correctly identify exceptions. Rare inherited polyposis syndromes need to be recognized because of their increased risk of intestinal and extra-intestinal malignancies. Furthermore, a correct diagnosis and treatment of rare gastro-intestinal malignancies is crucial. METHODS: Between 2016 and 2018 we encountered 4 different types of intestinal polyps. A database search was performed and patient files were checked for clinical manifestations and histo- pathology. Literature was searched to recapitulate red flags for these syndromes, probability of underlying genetic disorders and diagnostic criteria. RESULTS: Between 2016 and 2018, 28 patients presented at the Ghent University Hospital with 30 juvenile polyps. Furthermore, we diagnosed juvenile polyposis syndrome, Li Fraumeni syndrome and familial adenomatous polyposis (FAP) in 1 patient each, whilst 2 FAP patients were in follow-up. Each of these diagnoses has a different lifetime risk of (extra)-intestinal malignancy and requires a different approach and follow-up. Histopathology and genetic testing play an important role in identifying these syndromes in pediatric patients. CONCLUSION: Although most intestinal polyps in childhood are benign juvenile polyps that require no follow-up, rare inherited syndromes should be considered and correctly diagnosed since adequate follow-up is necessary to reduce morbidity and mortality from both gastrointestinal and extraintestinal complications and malignancies.

Bilateral vanishing hips, coincidence or systemic disease? A case report and overview of current literature.

Rapidly progressive hip disease (RDHD) is a rare condition of the hip joint, causing destruction of the femoral head. The pathogenesis is unknown. The disease is self-limiting, there is no treatment to stop the disease. Hip arthroplasty is a successful way to relieve pain and restore function. We present a case where both hips were involved and analysed. A favourable result was obtained by bilateral total hip arthroplasty.

Vibrational properties of organic donor-acceptor molecular crystals: Anthracene-pyromellitic-dianhydride (PMDA) as a case study.

We establish a reliable quantum-mechanical approach to evaluate the vibrational properties of donor-acceptor molecular crystals. The anthracene-PMDA (PMDA = pyromellitic dianhydride) crystal, where anthracene acts as the electron donor and PMDA as the electron acceptor, is taken as a representative system for which experimental non-resonance Raman spectra are also reported. We first investigate the impact that the amount of nonlocal Hartree-Fock exchange (HFE) included in a hybrid density functional has on the geometry, normal vibrational modes, electronic coupling, and electron-vibrational (phonon) couplings. The comparison between experimental and theoretical Raman spectra indicates that the results based on the αPBE functional with 25%-35% HFE are in better agreement with the experimental results compared to those obtained with the pure PBE functional. Then, taking αPBE with 25% HFE, we assign the vibrational modes and examine their contributions to the relaxation energy related to the nonlocal electron-vibration interactions. The results show that the largest contribution (about 90%) is due to electron interactions with low-frequency vibrational modes. The relaxation energy in anthracene-PMDA is found to be about five times smaller than the electronic coupling.

Freezing-in orientational disorder induces crossover from thermally-activated to temperature-independent transport in organic semiconductors.

The crystalline structure of organic materials dictates their physical properties, but while significant research effort is geared towards understanding structure-property relationships in such materials, the details remain unclear. Many organic crystals exhibit transitions in their electrical properties as a function of temperature. One example is the 1:1 charge-transfer complex trans--stilbene-2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane. Here we show that the mobility and resistivity of this material undergo a transition from being thermally activated at temperatures above 235 K to being temperature independent at low temperatures. On the basis of our experimental and theoretical results, we attribute this behaviour to the presence of a glass-like transition and the accompanied freezing-in of orientational disorder of the stilbene molecule.

Silicon photonics broadband modulation-based isolator.

We discuss an optical isolator design based on tandem phase modulators in a long interferometer. It provides low-loss, broadband isolation in a photonic integrated circuit without requiring special materials or fabrication steps. It was demonstrated in silicon photonics.

Reflectionless grating couplers for Silicon-on-Insulator photonic integrated circuits.

We propose a novel grating coupler design which is inherently reflectionless by focusing the reflected light away from the entrance waveguide. The design rules for this reflectionless grating coupler are explained and the grating coupler design is investigated by means of 3D FDTD simulations for the case of a Silicon-on-Insulator based platform.

High-efficiency fiber-to-chip grating couplers realized using an advanced CMOS-compatible silicon-on-insulator platform.

A new generation of Silicon-on-Insulator fiber-to-chip grating couplers which use a silicon overlay to enhance the directionality and thereby the coupling efficiency is presented. Devices are realized on a 200 mm wafer in a CMOS pilot line. The fabricated fiber couplers show a coupling efficiency of -1.6 dB and a 3 dB bandwidth of 80 nm.

Bridging the gap between nanophotonic waveguide circuits and single mode optical fibers using diffractive grating structures.

In this paper, the use of diffractive grating structures to efficiently interface between a single mode fiber and a high index contrast waveguide circuit is outlined. We show that high index contrast grating structures allow for broadband and high efficiency coupling. Since no polished facet is required on the photonic integrated circuit to interface with the optical fiber, fiber-to-chip grating couplers enable wafer-scale testing, reducing the cost for testing large scale integrated optical circuits. We show that two-dimensional grating structures can solve the problem of the huge polarization dependence of high index contrast photonic integrated circuits. Finally, an optical probe is presented, which allows testing individual components of a photonic integrated circuit, analogous to the electrical probes used in micro-electronics.

Pseudomonas fluorescens lipase adsorption and the kinetics of hydrolysis in a dynamic emulsion system.

To elucidate the adsorption characteristics of lipases and to study the influence of the reaction conditions on the catalytic properties of lipases, the hydrolysis of decylchloroacetate by Pseudomonas fluorescens lipase in an emulsion reactor was studied as a model system. During the reaction the droplet size distribution of the emulsion was measured on-line using a particle sizer based on light scattering. Desorption experiments revealed that, at low surface coverage, the initial rate of reaction was not influenced by either the stirring speed or the organic volume fraction. Dilution of the reaction mixture during hydrolysis did not result in a decrease in activity. Based on these results, it is assumed that under the specified conditions adsorption of Pseudomonas fluorescens lipase is quantitative and probably irreversible. Based on activity measurements and assuming that only a monolayer of lipase is active, it is calculated that at saturation the emulsion interface is covered with 3 mg lipase per m2. From these data the average interfacial area covered by one lipase molecule at saturation was calculated to be 1700-2100 A2 per molecule. The emulsion was shown to be dynamic, e.g., during hydrolysis a significant increase in interfacial area was observed as a result of a shift in droplet size distribution to smaller diameters. Experiments indicated that both the formation of decanol and the emulgating effect of the lipase account for these observations. The formation of decanol also resulted in a dramatic decrease in hydrolytic activity. Taking interfacial tension measurements into account, it is shown that decanol accumulates at the liquid-liquid interface.(ABSTRACT TRUNCATED AT 250 WORDS)

Total CK and CK-BB activity in serum from sheep with scrapie.

Total CK and iso-enzyme CK-BB activity was measured in serum from four sheep with scrapie and in serum from four healthy control sheep. Blood samples were taken weekly for about six months. There was a clear overlap between the total CK and CK-BB activity in serum from sheep with scrapie and that in serum from control sheep. Thus measurement of these enzymes does not aid the clinical diagnosis of scrapie.

Dose-response relationships between dietary (n-3) fatty acids and plasma and tissue lipids, steroid excretion and urinary malondialdehyde in rats.

For a 28-d experimental period, rats were fed a nonpurified, cereal-based diet containing 9.1% supplemental beef tallow or fish oil or one of the following beef tallow:fish oil blends: 95:5; 90:10; 80:20 and 50:50. All diets provided between 21.3 and 22.7 g linoleic acid/kg. Higher fish oil intake was paralleled by elevated incorporation of long-chain (n-3) fatty acids in plasma total lipid, mainly at the expense of arachidonic acid. Significant inverse relationships were found between plasma total (n-3) fatty acid concentration and plasma triglyceride, cholesterol or free fatty acid concentrations. Fish oil intake did not lead to a shift of triglycerides or cholesterol from the plasma to the tissues (liver, heart, kidneys). Reduced plasma cholesterol concentrations in the fish oil-fed rats could not be explained by higher fecal excretion of neutral sterols and bile acids. In vivo lipid peroxidation, assessed by urinary malondialdehyde excretion, was enhanced when diets containing greater than 1.8% fish oil were fed.

Lipid metabolism responses in rats fed beef tallow, native or randomized fish oil and native or randomized peanut oil.

In experiments with male Wistar rats, we measured the effects of nonpurified diets containing 9.1% added fat (beef tallow, native or randomized fish oil, native or randomized peanut oil) on apparent digestibility of total fat and individual fatty acids. We also investigated the effects of the diets on plasma contents of triglyceride, cholesterolesters and free and total cholesterol as well as on the fatty acid profiles of plasma and liver phospholipids. Randomization of fish oil or peanut oil had no significant effect on any of the lipid measurements. Fat digestibility was significantly lower in the rats fed beef tallow. Apparent absorption of 18:1(n-9) and polyunsaturated fatty acids was not dependent on the fatty acid profile of the dietary fat. Apparent absorption of 16:1(n-7) and saturated fatty acids was generally highest in the rats fed fish oil. Intake of fish oil or peanut oil significantly decreased plasma triglyceride content. Intake of fish oil resulted in substantially decreased contents of total cholesterol and cholesterolesters in plasma, but intake of peanut oil did not. Efficiency of conversion of 18:2(n-6) into 20:4(n-6) was inhibited by long-chain (n-3) fatty acids.

Digestion and absorption of free and esterified fish oil fatty acids in rats.

This study was designed to test the hypotheses that digestibility and post-absorption metabolism of fish oil are influenced by impaired lipolysis and by the stereospecific composition of its triacylglycerols. Male Wistar rats were fed nonpurified diets containing one of the following fat sources: 9% native fish oil (NFO), 9% autorandomized fish oil (RFO), 8.1% fish oil-derived free fatty acids (FO-FFA) plus 0.9% glycerol, or 9% soybean oil (SO) as a reference fat. In a 24-day balance study, apparent digestibility of total dietary fat averaged 93.1% in the SO, NFO and RFO groups, and 90.9% in the FO-FFA group. Randomization of fish oil had no effect on apparent digestibility of individual fatty acids. In rats fed FO-FFA, apparent absorption of saturated and monounsaturated fatty acids was lower when compared to the NFO and RFO groups. Feeding the FO-FFA diet tended to increase plasma triglyceride content. The hypocholesterolemic effect of polyunsaturated n-3 fatty acids was not influenced by the dietary source. Similar effects on fatty acid profiles of plasma and liver phospholipids were caused by the NFO, RFO and the FO-FFA diets. We conclude that once polyunsaturated n-3 fatty acids are absorbed, their effect on lipid metabolism is not determined by the dietary source.

Separation and quantitation of phospholipids in animal tissues by Iatroscan TLC/FID.

A procedure has been developed to separate and quantitate phospholipids, including phosphatidylinositol and phosphatidylserine, from animal tissues by means of the Iatroscan TLC/FID technique. The method is based on the use of 0.01 M oxalic acid impregnated Chromarods-SII and stepwise resolution of the phospholipids in the presence of 1,2-dipalmitoyl-sn-glycero-3-phospho (N,N-dimethylethanolamine) as internal standard. To remove the neutral lipids, the rods are initially developed in a non-polar solvent mixture followed by partial scanning. Next, the rods are impregnated with oxalic acid, developed twice in CHCl3/CH3OH/CH3COOH/HCOOH/H2O (80:35:2:1:3, v/v/v/v/v) and partially scanned for measuring lysophosphatidylcholine, sphingomyelin and phosphatidylcholine. The subsequent step involves double development in CHCl3/CH3OH/30% NH4OH (60:35:0.9, v/v/v) to resolve cardiolipin, internal standard, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine and phosphatidic acid. For each phospholipid a linear calibration curve with a highly significant correlation coefficient was obtained. However, the calibration lines extrapolated to negative intercepts on the ordinate, indicating declining sensitivity at low phospholipid loads.