Gastric lactobezoar - a rare disorder?

Gastric lactobezoar, a pathological conglomeration of milk and mucus in the stomach of milk-fed infants often causing gastric outlet obstruction, is a rarely reported disorder (96 cases since its first description in 1959). While most patients were described 1975-1985 only 26 children have been published since 1986. Clinically, gastric lactobezoars frequently manifest as acute abdomen with abdominal distension (61.0% of 96 patients), vomiting (54.2%), diarrhea (21.9%), and/or a palpable abdominal mass (19.8%). Respiratory (23.0%) and cardiocirculatory (16.7%) symptoms are not uncommon. The pathogenesis of lactobezoar formation is multifactorial: exogenous influences such as high casein content (54.2%), medium chain triglycerides (54.2%) or enhanced caloric density (65.6%) of infant milk as well as endogenous factors including immature gastrointestinal functions (66.0%), dehydration (27.5%) and many other mechanisms have been suggested. Diagnosis is easy if the potential presence of a gastric lactobezoar is thought of, and is based on a history of inappropriate milk feeding, signs of acute abdomen and characteristic features of diagnostic imaging. Previously, plain and/or air-, clear fluid- or opaque contrast medium radiography techniques were used to demonstrate a mass free-floating in the lumen of the stomach. This feature differentiates a gastric lactobezoar from intussusception or an abdominal neoplasm. Currently, abdominal ultrasound, showing highly echogenic intrabezoaric air trapping, is the diagnostic method of choice. However, identifying a gastric lactobezoar requires an investigator experienced in gastrointestinal problems of infancy as can be appreciated from the results of our review which show that in not even a single patient gastric lactobezoar was initially considered as a possible differential diagnosis. Furthermore, in over 30% of plain radiographs reported, diagnosis was initially missed although a lactobezoar was clearly demonstrable on repeat evaluation of the same X-ray films. Enhanced diagnostic sensitivity would be most rewarding since management consisting of cessation of oral feedings combined with administration of intravenous fluids and gastric lavage is easy and resolves over 85% of gastric lactobezoars. In conclusion, gastric lactobezoar is a disorder of unknown prevalence and is nowadays very rarely published, possibly because of inadequate diagnostic sensitivity and/or not yet identified but beneficial modifications of patient management

Changes in the Cerebrospinal Fluid and Plasma Lipidome in Patients with Rett Syndrome

Rett syndrome (RTT) is defined as a rare disease caused by mutations of the methyl-CpG binding protein 2 (MECP2). It is one of the most common causes of genetic mental retardation in girls, characterized by normal early psychomotor development, followed by severe neurologic regression. Hitherto, RTT lacks a specific biomarker, but altered lipid homeostasis has been found in RTT model mice as well as in RTT patients. We performed LC-MS/MS lipidomics analysis to investigate the cerebrospinal fluid (CSF) and plasma composition of patients with RTT for biochemical variations compared to healthy controls. In all seven RTT patients, we found decreased CSF cholesterol levels compared to age-matched controls (n = 13), whereas plasma cholesterol levels were within the normal range in all 13 RTT patients compared to 18 controls. Levels of phospholipid (PL) and sphingomyelin (SM) species were decreased in CSF of RTT patients, whereas the lipidomics profile of plasma samples was unaltered in RTT patients compared to healthy controls. This study shows that the CSF lipidomics profile is altered in RTT, which is the basis for future (functional) studies to validate selected lipid species as CSF biomarkers for RTT

Enhancement of CURB65 score with proadrenomedullin (CURB65-A) for outcome prediction in lower respiratory tract infections: Derivation of a clinical algorithm

Proadrenomedullin (ProADM) confers additional prognostic information to established clinical risk scores in lower respiratory tract infections (LRTI). We aimed to derive a practical algorithm combining the CURB65 score with ProADM-levels in patients with community-acquired pneumonia (CAP) and non-CAP-LRTI

ATR-IR spectroscopy at the metal-liquid interface: Influence of film properties on anomalous band-shape

Attenuated total reflection (ATR) spectra of adsorbates and solvent on thin metal films were investigated with emphasis on the band-shape of absorption bands. Distorted band-shapes are found even far from the critical angle. Strong absorption bands are more distorted. The band-shape strongly depends on the optical constants of the metal film and its thickness. The distortion increases with increasing thickness and increasing refractive index of the thin metal film. For a 10 nm thick Pt film the measured band-shapes for liquid water and ethanol are in good agreement with theoretical predictions using the bulk optical constants for Pt. For CO adsorbed on a 1 nm Pt film a distorted band-shape is observed whereas calculations assuming bulk optical constants predict band-shape distortion only for considerably thicker Pt films. The effective optical constants for very thin metal films deviate considerably from the bulk values, due to the island structure of the film and non-adiabatic effects can lead to distorted band-shapes. Structural changes within a Pt film, induced by hydrogen treatment, leads to a change in the band-shape for adsorbed CO. The results show that band-shape analysis is a valuable tool for in situ ATR IR spectroscopy of metal films

Shining Light at Working Interfaces and Chiral Nanoparticles

In this article we present an overview of our recent research in the fields of in situ spectroscopy, nanomaterials and chirality. Our research focuses around the spectroscopic investigation of chemical reactions taking place at solid-liquid interfaces. This research goesh and in hand with the development of experimental techniques that enable us to study interface phenomena in situ. Using such techniques we try to shed light on photocatalytic reactions like the decomposition of organic pollutants in water or the reduction of carbon dioxide. We are moreover interested in chiral surfaces and their ability to discriminate betweenen antiomers. Again this relies on special techniques that highlight the enantiodiscriminating surface-adsorbate interactions. We further more seek to transfer chirality from adsorbates to metal nanoparticles. The latter are probed by chiroptical techniques, particularly also vibrational circular dichroism (VCD). Finally, we aim at preparing metamaterials with tailored optical properties by organizing plasmonic particles in two and three dimensions

Properties of the gold–sulphur interface: from self-assembled monolayers to clusters

The gold–sulphur interface of self-assembled monolayers (SAMs) was extensively studied some time ago. More recently tremendous progress has been made in the preparation and characterization of thiolate-protected gold clusters. In this feature article we address different properties of the two systems such as their structure, the mobility of the thiolates on the surface and other dynamical aspects, the chirality of the structures and characteristics related to it and their vibrational properties. SAMs and clusters are in the focus of different communities that typically use different experimental approaches to study the respective systems. However, it seems that the nature of the Au–S interfaces in the two cases is quite similar. Recent single crystal X-ray structures of thiolate-protected gold clusters reveal staple motifs characterized by gold ad-atoms sandwiched between two sulphur atoms. This finding contradicts older work on SAMs. However, newer studies on SAMs also reveal ad-atoms. Whether this finding can be generalized remains to be shown. In any case, more and more studies highlight the dynamic nature of the Au–S interface, both on flat surfaces and in clusters. At temperatures slightly above ambient thiolates migrate on the gold surface and on clusters. Evidence for desorption of thiolates at room temperature, at least under certain conditions, has been demonstrated for both systems. The adsorbed thiolate can lead to chirality at different lengths scales, which has been shown both on surfaces and for clusters. Chirality emerges from the organization of the thiolates as well as locally at the molecular level. Chirality can also be transferred from a chiral surface to an adsorbate, as evidenced by vibrational spectroscopy

In situ spectroscopy of catalytic solid-liquid interfaces and chiral surfaces

This contribution gives an overview of our recent effort to probe catalytic solid-liquid interfaces in situ and to investigate recognition processes at chiral surfaces. Attenuated total reflection infrared spectroscopy in a dedicated low volume flow-through cell is used to investigate the working catalytic interface. The latter technique is combined with modulation spectroscopy, which relies on the perturbation of the system under investigation by a periodically varying external parameter. A digital phase-sensitive detection results in high quality spectra. The method furthermore yields kinetic information and helps disentangle complex spectra. The described tool is therefore ideally suited for the investigation of complex systems. Applications in the fields of heterogeneous catalysis and recognition at chiral solid-liquid interfaces are presented. Our aim is a better molecular level understanding of these processes and, based on this knowledge, a rational design of better catalyst materials

Heterogeneous Enantioselective Hydrogenation over Cinchona Alkaloid Modified Platinum: Mechanistic Insights into a Complex Reaction

Modification of a metal surface by a strongly adsorbed chiral organic molecule has proven to be an interesting strategy for heterogeneous chiral catalysis. Platinum chirally modified by cinchona alkaloids, successfully applied for the enantioselective hydrogenation of α-ketoesters, is probably the most prominent catalyst based on this concept. Despite considerable research efforts toward understanding of this complex catalytic system, the proposed mechanistic models are still debated. Here we discuss how enantiodifferentiation can be induced on a catalytically active surface and validate the models proposed for the platinum−cinchona system in the light of the existing molecular knowledge

Photoinduced electron transfer and photodegradation of malonic acid at Au/TiO2 investigated by in situ ATR-IR spectroscopy

TiO2 coated Au nanoparticles were synthesized and characterized by TEM, XPS and XRD. It was found that the Au nanoparticles were coated with TiO2 thus forming a core-shell structure. Electron transfer, adsorption and photodegradation of malonic acid on the catalyst were investigated by in situ attenuated total reflection infrared (ATR-IR) spectroscopy. Malonic acid adsorbed and underwent photodegradation efficiently in air and nitrogen atmosphere under UV light illumination on the prepared catalyst. As intermediate species oxalate was observed on the catalyst surface during the photodegradation of malonic acid. The Au nanoparticles accelerate the degradation of malonic acid by capturing the conduction band electrons of TiO2. The ATR spectra also reveal interface electron transfer from Au nanoparticles to TiO2 under visible light illumination and from TiO2 to Au nanoparticles under UV illumination. (C) 2012 Elsevier B.V. All rights reserved.TiO2 coated Au nanoparticles were synthesized and characterized by TEM, XPS and XRD. It was found that the Au nanoparticles were coated with TiO2 thus forming a core-shell structure. Electron transfer, adsorption and photodegradation of malonic acid on the catalyst were investigated by in situ attenuated total reflection infrared (ATR-IR) spectroscopy. Malonic acid adsorbed and underwent photodegradation efficiently in air and nitrogen atmosphere under UV light illumination on the prepared catalyst. As intermediate species oxalate was observed on the catalyst surface during the photodegradation of malonic acid. The Au nanoparticles accelerate the degradation of malonic acid by capturing the conduction band electrons of TiO2. The ATR spectra also reveal interface electron transfer from Au nanoparticles to TiO2 under visible light illumination and from TiO2 to Au nanoparticles under UV illumination. (C) 2012 Elsevier B.V. All rights reserved