Myeloradiculitis: a rare event in schistosoma infection

Schistosomiasis a parasitic disease caused by trematodes is widely distributed in (sub-)tropical countries. Depending on the species the infection manifests clinically as gastrointestinal (preferentially Schistosoma mansoni and S. japonicum) or urinary (preferentially S. haematobium) disorders. Here we present an uncommon case of myeloradiculitis leading to bladder palsy and sensory loss at the lower limbs.

Plasmodesmata and intercellular transport of viral RNA

Cell-to-cell communication in plants involves the symplastic trafficking of informational protein and RNA macromolecules through cytoplasmic bridges in the plant cell wall known as plasmodesmata. Viruses exploit this route for the spread of infection and are used as a model to study the mechanisms by which macromolecules are targeted to the pore. Studies using tobacco mosaic virus have led to the identification of host components that participate in plasmodesmal targeting of viral RNA and movement protein.

Safety and feasibility of evaluating airway-protective reflexes during sleep: new technique and preliminary results

BACKGROUND

The airway is vulnerable to aspiration during sleep. The integrity of aerodigestive-protective reflexes during sleep has not been studied previously because of a lack of adequate techniques.

OBJECTIVE

To determine the safety and the feasibility of a new technique to elicit pharyngoglottal closure reflex (PGCR), pharyngo-upper-esophageal sphincter (UES) pressure contractile reflex (PUCR), and reflexive pharyngeal swallow (RPS) during sleep.

SETTING

Outpatient sleep laboratory.

DESIGN AND INTERVENTION

PGCR, PUCR, and RPS were elicited in 3 subjects by injecting colored water into the pharynx through a specially designed UES manometry catheter to which a thin videoendoscope was taped. This assembly was passed transnasally and positioned to obtain UES-pressure recordings and adequate endoscopic glottic views. Sleep was monitored by polysomnography, and all modalities were synchronized by using a timer. Subjects were evaluated while awake and during stage I sleep.

RESULTS

All subjects were monitored for 3 hours of natural sleep, during which several periods of stage I sleep were observed. While awake, PGCR, PUCR, and RPS were elicited in all subjects. During sleep, PGCR was present in all, PUCR in 2, and RPS in 2 (1 after arousal) subjects. Threshold volumes for reflex elicitation were not significantly different between the awake state and stage I sleep. None of the subjects exhibited laryngeal penetration or aspiration.

LIMITATIONS

Small numbers of subjects were studied only in stage I sleep.

CONCLUSIONS

When using the above technique, it is safe and feasible to study aerodigestive reflexes during sleep. Preliminary data suggest that PGCR, PUCR, and RPS can be elicited during sleep.

Photon statistics of semiconductor microcavity lasers

We present measurements of first- and second-order coherence of quantum-dot micropillar lasers together with a semiconductor laser theory. Our results show a broad threshold region for the observed high-beta microcavities. The intensity jump is accompanied by both pronounced photon intensity fluctuations and strong coherence length changes. The investigations clearly visualize a smooth transition from spontaneous to predominantly stimulated emission which becomes harder to determine for high beta. In our theory, a microscopic approach is used to incorporate the semiconductor nature of quantum dots. The results are in agreement with the experimental intensity traces and the photon statistics measurements.

Performance and optimal technique for pharyngeal impedance recording: A simulated pharyngeal reflux study

BACKGROUND AND AIMS

Detection rate, influence of recording site, and subject posture for impedance monitoring of pharyngeal reflux of gastric contents remain unknown. We evaluated the ability of the impedance sensor for detection of various volumes of intrapharyngeal infusate at two sites and in two subject positions.

METHODS

Nineteen healthy subjects were studied using concurrent videoendoscopic, manometric, impedance, and pH recording.

RESULTS

Detection rate of simulated pharyngeal reflux events ranged between 87% and 100% for 1-4 mL. Detection rate for 0.1-1 mL volumes in the upright position was significantly higher (78-85%) when the impedance sensor was located at the proximal margin of the upper esophageal sphincter (UES) compared to 2 cm proximally (38-68%) (P < 0.001). With the sensor at 2 cm above the UES, the average detection rate for all volumes in the upright position was significantly less (P < 0.001) compared to the supine position (48%vs 84%). There was substantial variability in the magnitude of impedance changes induced by different infusates.

CONCLUSIONS

Impedance sensors can detect as small a volume as 0.1 mL and combined with a pH sensor can detect acidic and nonacidic liquid and mist reflux events. Sensor placement at the proximal margin of the UES yields the highest detection rate irrespective of subject posture compared to placement 2 cm proximally. Depending on the volume of refluxate and location of the impedance sensor, a substantial minority of simulated reflux events can be missed.

Impedance signature of pharyngeal gaseous reflux

BACKGROUND

Pharyngeal impedance changes induced by various pharyngeal reflux events have not been characterized.

OBJECTIVES

To characterize pharyngeal impedance changes induced by participant-perceived belching events.

METHODS

We systematically evaluated pharyngeal impedance and pH changes related to 453 belch events in 11 gastroesophageal reflux disease, 10 reflux attributed-laryngitis patients and 16 controls.

RESULTS

Of 453 belch events, 362 were analyzable. Of these, 72% occurred within 10 s, 93% within 20 s, 99% within 30 s and 100% within 40 s of the time that participants marked a belch event. In 15% impedance changes in the pharynx preceded, in 12% they were simultaneous and in 73% they occurred after the start of the impedance change in the proximal esophagus. Time interval between the two events ranged between 0.4+/-0.03 and 0.7+/-0.1 s. In all, there were three types of belch-induced impedance changes: (a) impedance increase, (b) impedance decrease and (c) multiphasic. Twenty percent of impedance events associated with belching had less than 50% change from baseline, whereas in 51% changes exceeded or were equal to 50%. Among events with a drop in pharyngeal impedance, only two satisfied the criteria for the liquid reflux event.

CONCLUSIONS

Pharyngeal ventilation of gastric gaseous content seems to have a unique impedance signature. During pharyngeal gas reflux events, impedance changes may start before or after proximal esophageal changes. Belching may induce negative pharyngeal changes that do not meet the criteria for liquid reflux. These findings need to be taken into consideration in the analysis of pharyngeal reflux events.

Moebius sequence: behaviour problems of preschool children and parental stress

This study investigates behaviour problems of preschool children with Moebius sequence, and their primary caregivers' stress. To this end, parents of all preschool children with Moebius sequence known to the German Moebius foundation were anonymously asked to fill out questionnaires, e.g. the Child Behavior Checklist [CBCL] 1.5-5. The primary caregivers of 13/22 children (seven males, six females; mean age: 3;10 [2;1-5;11] years) sent back filled-out questionnaires. Two children were rated as clinical on the CBCL-1.5-5. Boys had significantly higher scores on the scales aggressive behavior and total problems than girls. Compared to the general population, but not to other parents of mentally and / or physically handicapped children, the primary caregivers experienced higher levels of stress. In conclusion, preschool children with Moebius sequence do not show essentially increased rates of clinical behaviour problems. Nevertheless, their primary caregivers experience increased stress and need early and adequate support.

Spin-Coated Polyethylene Films Probed by Single Molecules

We have studied ultrathin spin-coated high-density polyethylene films by means of single-molecule spectroscopy and microscopy at 1.8 K. The films have been doped with 2.3,8.9-dibenzanthanthrene (DBATT) molecules, which function as local reporters of their immediate environment. The orientation distributions of single DBATT probe molecules in 100-200 nm thin films of high-density polyethylene differ markedly from those in low-density films. We have found a preferential orientation of dopant molecules along two well-defined, mutually perpendicular directions. These directions are preserved over at least a 2 mm distance. The strong orientation preference of the probe molecules requires the presence of abundant lateral crystal faces and is therefore not consistent with a spherulitic morphology. Instead, a "shish-kebab" crystal structure is invoked to explain our results.

Biosynthetic gene cluster for the polyenoyltetramic acid alpha-lipomycin

The gram-positive bacterium Streptomyces aureofaciens Tü117 produces the acyclic polyene antibiotic alpha-lipomycin. The entire biosynthetic gene cluster (lip gene cluster) was cloned and characterized. DNA sequence analysis of a 74-kb region revealed the presence of 28 complete open reading frames (ORFs), 22 of them belonging to the biosynthetic gene cluster. Central to the cluster is a polyketide synthase locus that encodes an eight-module system comprised of four multifunctional proteins. In addition, one ORF shows homology to those for nonribosomal peptide synthetases, indicating that alpha-lipomycin belongs to the classification of hybrid peptide-polyketide natural products. Furthermore, the lip cluster includes genes responsible for the formation and attachment of d-digitoxose as well as ORFs that resemble those for putative regulatory and export functions. We generated biosynthetic mutants by insertional gene inactivation. By analysis of culture extracts of these mutants, we could prove that, indeed, the genes involved in the biosynthesis of lipomycin had been cloned, and additionally we gained insight into an unusual biosynthesis pathway.

Coherent photonic coupling of semiconductor quantum dots

We report a new type of coupling between quantum dot excitons mediated by the strong single-photon field in a high-finesse micropillar cavity. Coherent exciton coupling is observed for two dots with energy differences of the order of the exciton-photon coupling. The coherent coupling mode is characterized by an anticrossing with a particularly large line splitting of 250 microeV. Because of the different dispersion relations with temperature, the simultaneous photonic coupling of quantum dot excitons can be easily distinguished from cases of sequential strong coupling of two quantum dots.

Lisuride, a dopamine receptor agonist with 5-HT2B receptor antagonist properties: absence of cardiac valvulopathy adverse drug reaction reports supports the concept of a crucial role for 5-HT2B receptor agonism in cardiac valvular fibrosis

OBJECTIVES

The high incidence of fibrotic cardiac valvulopathies reported in association with the 8beta-ergoline dopamine (DA) agonist, pergolide, and also case reports for cabergoline and bromocriptine have made it necessary to review the theoretical basis and actual findings in the case of another DA agonist, the 8alpha-ergoline lisuride (used since the 1970s for migraine prophylaxis as well as since the 1980s for its prolactin-lowering and anti-Parkinson activity).

METHODS

We have reviewed the pharmacology of lisuride in relation to other DA agonists, and we have performed a throughout literature search as well as a search of our own and other adverse drug reaction databases for a possible relationship of lisuride with cardiac valvulopathy or for any reports of fibrosis in other locations.

RESULTS

Our review of the pharmacology and the literature strongly suggests that drug-induced cardiac valvulopathies are always related to a stimulatory drug effect on trophic 5-HT(2B) receptors. As lisuride is devoid of such an effect, but on the contrary is an extremely potent 5-HT(2B) antagonist, an association of lisuride therapy with cardiac valvulopathies seems to be highly unlikely. In agreement with this hypothesis, not a single report of a cardiac valvulopathy associated with lisuride therapy has been identified in any database so far.Furthermore, against a background of an estimated 360,000 patient years, we have found only a very small number of cases of any other form of fibrosis (1x retroperitoneal, 2x pleural, 2x pulmonary, 1x interstitial pulmonary changes), in part combined with other risk factors and confounding variables. This closely matches 4 reports available from WHO (1x retroperitoneal, 3x pleural fibrosis). In addition, only 5 other possibly related conditions (3x pleural effusion, 1x pleuritis, 1x pericarditis) were identified in the lisuride adverse drug reaction database of Schering, Berlin.

CONCLUSIONS

No link has been found between lisuride use and fibrotic cardiac valvulopathy, in agreement with the 5-HT(2B) receptor antagonist effect of this drug. The very low incidence of spontaneous reports of any other fibrosis could be even compatible with an association by chance in the population exposed to lisuride. Although close monitoring for this kind of side effects is still to be recommended in the therapy with lisuride, our data do not support the concept of a class effect suggesting that all ergot-derived drugs and especially DA receptor agonists with some chemical similarity to the ergot structure will cause or facilitate cardiac valvulopathies as observed with pergolide.

Effect of aging on bolus kinematics during the pharyngeal phase of swallowing

Swallowing difficulty is a common complaint in the elderly and, although there are data for the biomechanics of liquid swallows, little is known about solid bolus motion, or kinematics, in the elderly. The aims of this study were as follows: 1) to characterize and compare solid and liquid bolus kinematics in the elderly and compare the findings with those in young subjects and 2) to correlate bolus kinematics and dynamics. Concurrent manometric-fluoroscopic techniques were used to study eight young and eight elderly subjects. The subjects performed four swallows each of 0.2-cm-diameter solid barium pellets and 5 ml of liquid barium during sagittal fluoroscopy and six-channel pharyngoesophageal manometry. Images were digitized for analysis of kinematic properties such as velocity and acceleration. Dynamic pressures were recorded and coordinated with kinematic events. Image analysis showed that velocity varied as the pellet passed through the hypopharynx, pharynx, and upper esophageal sphincter. In young subjects, pellet kinematics were characterized by two zones of pellet acceleration: one over the tongue base and another as the pellet passed through the upper esophageal sphincter. Although the elderly showed a similar zone of acceleration over the base of the tongue, the second zone of pellet acceleration was not seen. Decreasing pressure gradients immediately distal to the position of the solid pellet and liquid bolus characterized dynamics for all subjects. This decreasing pressure gradient was significantly larger in elderly than in young subjects. Bolus kinematics and dynamics were significantly altered among elderly compared with young subjects. Among these differences were the absence of hypopharyngeal bolus acceleration and a significant increase in the trans-sphincteric pressure gradient in the elderly.

Glycocalyx-mimetic dextran-modified poly(vinyl amine) surfactant coating reduces platelet adhesion on medical-grade polycarbonate surface

A dextran-modified poly(vinyl amine) comb-like surfactant polymer, poly(N-vinyl dextran aldonamide-co-N-vinyl hexanamide), that can surface-adsorb on hydrophobic polymeric substrates, was designed to improve the interfacial blood-compatibility of polymeric biomaterials. Medical-grade polycarbonate was selected as a model substrate because of its extensive use in blood-contacting biomedical devices like hemodialyzers, blood pumps and oxygenators. The surfactant polymer was physisorbed from aqueous solution onto the polycarbonate substrate. The surfactant coating was stable under dynamic shear conditions in whole blood, as confirmed by fluorescence microscopy and total internal reflection fluorescence (TIRF) experiments with fluorescein-labeled surfactant polymer. The coated disks and uncoated control disks were exposed to platelet-rich plasma (PRP) and whole human blood in a rotating disk system (RDS) to study platelet-adhesion under dynamic shear stress environments. Adhered platelets were stained with fluorescein isothiocyante (FITC)-tagged anti-CD41a monoclonal antibody and imaged by epifluorescence microscopy. Complimentary images were obtained by phase-contrast microscopy. Platelet adhesion on the surfactant-coated disks was reduced by approximately 90%, compared with uncoated disks. The images also showed a concomitant reduction in platelet-derived microparticles on surfactant-coated disks, compared with uncoated disks. The results suggest potential application of carbohydrate-modified surfactant polymers as a glycocalyx-mimetic non-thrombogenic interfacial coating for blood-contacting biomaterials.

Novel evidence for hypersensitivity of visceral sensory neural circuitry in irritable bowel syndrome patients

BACKGROUND & AIMS

Visceral hypersensitivity in irritable bowel syndrome (IBS) patients has been documented by evaluation of perceived stimulations that can reflect abnormalities of both sensory neurocircuitry and cognitive processes. The presence of actual neurohypersensitivity in human beings has not been documented separately. Because subliminal stimulations are free from the influence of stimulus-related cognitive processes, functional magnetic resonance imaging (fMRI) cortical response to these stimuli can be considered a measure of activity of the neural circuitry alone. The aim of this study was to compare quantitatively the cerebral cortical fMRI activity response to equal subliminal stimulations between IBS patients and age-matched controls.

METHODS

We studied 10 IBS patients and 10 healthy controls using a computerized barostat-controlled rectal distention device. fMRI activity volume and percent maximum signal intensity change for equal subliminal distention pressures were compared between controls and patients.

RESULTS

Three levels of subliminal distention pressures (eg, 10, 15, and 20 mm Hg), were represented in both controls and patients and were analyzed for fMRI response. In all 3 distention levels the fMRI activity volume in IBS patients was significantly larger than age- and sex-matched controls (P < .05). The percent maximum signal intensity change was similar between IBS patients and controls.

CONCLUSIONS

The volume of cerebral cortical activity response to equal subliminal distention pressures in IBS patients is significantly larger than in controls, documenting the existence of hypersensitivity of the neural circuitry in this patient group irrespective of stimulus-related cognitive processes.

Influence of sleep stages on esophago-upper esophageal sphincter contractile reflex and secondary esophageal peristalsis

BACKGROUND & AIMS

Airways are most vulnerable to aspiration during sleep. Esophago-upper esophageal sphincter (UES) contractile reflex (EUCR) and secondary peristalsis (2P) have been proposed to protect the airway by reflexively contracting the UES and clearing the esophagus of refluxate, respectively. Our aim was to study EUCR and 2P elicitation in "awake" state, stage II, slow-wave (stage III/IV), and rapid eye movement (REM) sleep.

METHODS

Thirteen healthy volunteers were studied in the supine position using concurrent UES and esophageal manometry and polysomnography. Threshold volume (Tvol) to trigger EUCR and 2P and changes in sleep stages were recorded during injection of 2.7 mL/min water into the proximal esophagus after sleep stages were confirmed.

RESULTS

UES pressure progressively declined with deeper stages of sleep. Tvol for EUCR and 2P elicitation was not significantly different between the stage II and "awake" state (EUCR: 4.0 +/- 1.8 mL vs 6.1 +/- 3.6 mL stage II; 2P: 5.8 +/- 2.2 mL vs 8.0 +/- 4.0 mL stage II). Tvol for EUCR and 2P elicitation during REM sleep were significantly lower than during the stage II and "awake" state (REM EUCR: 2.2 +/- 1.1 mL; 2P: 3.5 +/- 1.2 mL). Arousal and cough preempted development of EUCR and 2P during slow-wave sleep.

CONCLUSIONS

(1) EUCR/2P can be elicited in stage II and REM but is preempted by arousal in slow-wave sleep. (2) Tvol for EUCR/2P elicitation is significantly lower in REM, compared with the stage II and "awake" state, suggesting a heightened sensitivity of these reflexes during REM sleep. (3) Although UES pressure progressively declines with deeper stages of sleep, it can still reflexively contract during REM sleep, despite generalized hypotonia.