GM1/GalNAc-GD1a complex: a target for pure motor Guillain-Barre syndrome

BACKGROUND

GM1 and GalNAc-GD1a are located on the axolemma of the motor nerves and are believed to be the antigens associated with pure motor Guillain-Barré syndrome (GBS). Furthermore, GM1 and GalNAc-GD1a may exist nearby and colocalize on the axolemma. Ganglioside complex (GSC) antigens associated with GM1 or GalNAc-GD1a can be target antigens in pure motor GBS. We investigated GBS sera for antibodies to a GSC consisting of GM1 and GalNAc-GD1a (GM1/GalNAc-GD1a) and analyzed the clinical and electrophysiologic findings of patients with antibodies to GM1/GalNAc-GD1a.

METHODS

Sera from 224 patients with GBS were surveyed for antibodies to GSCs consisting of two of nine gangliosides (GM1, GM2, GM3, GD1a, GD3, GT1a, GT1b, GQ1b, and GalNAc-GD1a). We analyzed the clinical and electrophysiologic features of patients with IgG antibodies to the GM1/GalNAc-GD1a complex.

RESULTS

Ten patients with GBS had IgG antibodies to the GM1/GalNAc-GD1a complex. The clinical findings of the 10 patients with GBS were characterized by preserved sensory system and infrequent cranial nerve deficits. According to the criteria established by Hadden et al., electrodiagnostic studies showed a demyelinating pattern in four patients and axonal neuropathy pattern in two. Early motor conduction block at intermediate nerve segments was found in five patients.

CONCLUSIONS

GM1 and GalNAc-GD1a may form a complex in the axolemma at nodes of Ranvier or paranodes of the motor nerves, and may be a target antigen in pure motor Guillain-Barré syndrome, especially in the form of acute motor conduction block neuropathy.

The influence of obesity and metabolic risk variables on brachial-ankle pulse wave velocity in healthy adolescents

Measurement of brachial-ankle pulse wave velocity (baPWV) is recognized as a simple and practical method for assessing arterial stiffness. We determined whether the baPWV of adolescents is affected by obesity and its associated metabolic risk variables. A cross-sectional sample of 754 apparently healthy adolescents (383 men and 371 women), aged 15-17 years, was recruited for this study. baPWV was measured by a simple automatic oscillometric technique. Adiposity measures, blood pressure, serum lipoproteins, fasting glucose and insulin were evaluated. The baPWV of the adolescents was significantly higher in men than in women and increased with age in both genders. After being statistically adjusted for age and gender, baPWV was significantly correlated with body mass index, percent body fat, waist-to-height ratio, systolic and diastolic blood pressures, mean arterial pressure, triglycerides, high-density lipoprotein cholesterol (HDL-C), atherogenic index, glucose, insulin, and homoeostasis model assessment of insulin resistance (HOMA-IR). In the multivariate regression analysis, mean arterial pressure, atherogenic index, HOMA-IR, systolic blood pressure and age were found to be significant determinants of baPWV (P<0.001). An increasing number of clustered risk variables, including high values (>gender-specific top quartiles) of waist-to-height ratio, mean arterial pressure, atherogenic index and HOMA-IR showed a graded association with baPWV (P<0.001 for trend). These results suggest that obesity and its associated metabolic abnormalities are important factors in the increased baPWV of adolescents and that baPWV may be useful in investigating early arterial wall changes in this population.

Primary role of the barely occupied states in the charge density wave formation of NbSe2

NbSe2 is a prototypical charge-density-wave (CDW) material, whose mechanism remains mysterious so far. With angle resolved photoemission spectroscopy, we recovered the long-lost nesting condition over a large broken-honeycomb region in the Brillouin zone, which consists of six saddle band point regions with high density of states (DOS), and large regions away from Fermi surfaces with negligible DOS at the Fermi energy. We show that the major contributions to the CDW formation come from these barely occupied states rather than the saddle band points. Our findings not only resolve a long-standing puzzle, but also overthrow the conventional wisdom that CDW is dominated by regions with high DOS.

Isotopic fingerprint of electron-phonon coupling in high-Tc cuprates

Angle-resolved photoemission spectroscopy with low-energy tunable photons along the nodal direction of oxygen isotope substituted Bi(2)Sr(2)CaCu(2)O(8+delta) reveals a distinct oxygen isotope shift near the electron-boson coupling "kink" in the electronic dispersion. The magnitude (a few meV) and direction of the kink shift are as expected due to the measured isotopic shift of phonon frequency, and are also in agreement with theoretical expectations. This demonstrates the participation of the phonons as dominant players, as well as pinpointing the most relevant of the phonon branches.

Superconducting coherence peak in the electronic excitations of a single-layer Bi2Sr1.6La0.4CuO6+delta cuprate superconductor

Angle resolved photoemission spectroscopy study is reported on a high quality optimally doped Bi2Sr1.6La0.4CuO6+delta high-Tc superconductor. In the antinodal region with a maximal d-wave gap, the symbolic superconducting coherence peak, which has been widely observed in multi-CuO2-layer cuprate superconductors, is unambiguously observed in a single-layer system. The associated peak-dip separation is just about 19 meV, which is much smaller than its counterparts in multilayered compounds, but correlates with the energy scales of spin excitations in single-layer cuprates.

Evolution of the electronic structure of 1T-Cu(x)TiSe(2)

The electronic structure of a new charge-density-wave system or superconductor, 1T-Cu(x)TiSe(2), has been studied by photoemission spectroscopy. A correlated semiconductor band structure is revealed for the undoped case, which resolves a long-standing controversy in the system. With Cu doping, the charge-density wave is suppressed by the raising of the chemical potential, while the superconductivity is enhanced by the enhancement of the density of states, and possibly suppressed at higher doping by the strong scattering.

High-energy scale revival and giant kink in the dispersion of a cuprate superconductor

In the present photoemission study of a cuprate superconductor Bi1.74Pb0.38Sr1.88CuO6+delta, we discovered a large scale dispersion of the lowest band, which unexpectedly follows the band structure calculation very well. Similar behavior observed in blue bronze and the Mott insulator Ca2CuO2Cl2 suggests that the origin of hopping-dominated dispersion in an overdoped cuprate might be quite complicated. A giant kink in the dispersion is observed, and the complete self-energy containing all interaction information is extracted for a doped cuprate. These results recovered significant missing pieces in our current understanding of the electronic structure of cuprates.

Bulk- and surface-sensitive high-resolution photoemission study of two mott-hubbard systems: SrVO3 and CaVO3

We study the electronic structure of Mott-Hubbard systems SrVO3 and CaVO3 with bulk and surface-sensitive high-resolution photoemission spectroscopy, using a vacuum ultraviolet laser, synchrotron radiation, and a discharge lamp (hv = 7-21 eV). A systematic suppression of the density of states (DOS) within approximately 0.2 eV of the Fermi level (EF) is found on decreasing photon energy, i.e., on increasing bulk sensitivity. The coherent band in SrVO3 and CaVO3 is shown to consist of surface and bulk-derived features, separated in energy. The stronger distortion on surface of CaVO3 compared to SrVO3 leads to a higher surface metallicity in the coherent DOS at EF, consistent with recent theory.

RvE1 protects from local inflammation and osteoclast- mediated bone destruction in periodontitis

Periodontitis is a well-appreciated example of leukocyte-mediated bone loss and inflammation that has pathogenic features similar to those observed in other inflammatory diseases such as arthritis. Resolvins are a new family of bioactive products of omega-3 fatty acid transformation circuits initiated by aspirin treatment that counter proinflammatory signals. Because it is now increasingly apparent that local inflammation plays a critical role in many diseases, including cardiovascular disease, atherosclerosis, and asthma, experiments were undertaken to evaluate the actions of the newly described EPA-derived Resolvin E1 (RvE1) in regulation of neutrophil tissue destruction and resolution of inflammation. The actions of an aspirin-triggered lipoxin (LX) analog and RvE1 in a human disease, localized aggressive periodontitis (LAP), were determined. Results indicate that neutrophils from LAP are refractory to anti-inflammatory molecules of the LX series, whereas LAP neutrophils respond to RvE1. In addition, RvE1 specifically binds to human neutrophils at a site that is functionally distinct from the LX receptor. Consistent with these potent actions, topical application of RvE1 in rabbit periodontitis conferred dramatic protection against inflammation induced tissue and bone loss associated with periodontitis.

Abnormal response to physical activity in femurs after heterozygous inactivation of one allele of the Col2a1 gene for type II collagen in mice

The objective of this study was to evaluate the influence of heterozygous inactivation of one allele of the type II collagen gene (Col2a1) on biomechanical properties and mineral density of bone under physical loading conditions. C57BL/6-TGN mice with heterozygous knockout (HZK) inactivation of Col2a1 gene and their nontransgenic littermate controls were housed in individual cages with running wheels for 9 and 15 months. The running activity of each mouse was monitored continuously throughout the experiment. Bone mineral density (BMD) of mice femora was measured using dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computerized tomography (pQCT). Biomechanical properties were determined using three-point bending tests. Vertebral bone samples were prepared for quantitative polarized light microscopy and digital densitometry of proteoglycans. The concentration of total collagen and collagen cross-links were analyzed using high-performance liquid chromatograpy (HPLC). The average daily running distance was shorter for the HZK mice between the age of 4 and 15 months as compared with normal runners (P < 0.05). The ultimate breaking force was 14.8% and 23.6% (9 vs. 15 months) lower in HZK-runners than in wild-type runners. BMD of the femur was 6.1% lower in HZK-runners at the age of 9 months (P < 0.05). Physical activity increased cortical BMD in wild-type runners but not in the HZK runners at the age of 9 months. The collagen network of the HZK mice was less organized. There were only minor changes in BMD and mechanical and structural properties between sedentary HZK mice and their wild-type controls. Increased physical activity induced significantly lower bone density, mechanical properties, and organization of collagen fibers in male HZK mice. However, there were no major differences in biomechanical parameters between sedentary HZK and wild-type male mice. This suggests an important guiding role of collagen type II in bone remodelling and maturation.

Microbicidal efficacy of ozonated water against Candida albicans adhering to acrylic denture plates

BACKGROUND/AIMS

Ozone is known to act as a strong antimicrobial agent against bacteria, fungi, and viruses. We examined the effect of ozonated water on Candida albicans on acrylic denture plate.

METHODS

The heat-cured acrylic resins were cultured with C. albicans. After treatment of flowing ozonated water, the number of attached C. albicans was counted. In some experiments, the test samples were treated with ozonated water in combination with ultrasonication.

RESULTS

After exposure to flowing ozonated water (2 or 4 mg/l) for 1 min, viable C. albicans cells were nearly nonexistent. The combination of ozonated water and ultrasonication had a strong effect on the viability of C. albicans adhering to the acrylic resin plates. There were no significant differences in antimicrobial activity against C. albicans between plates immersed in ozonated water with ultrasonication and those treated with commercially available denture cleaners. In addition, electron microscopic analysis revealed that small amounts of C. albicans remained on the plate after exposure to flowing ozonated water or immersion in ozonated water with ultrasonication.

CONCLUSION

Our results suggest that application of ozonated water may be useful in reducing the number of C. albicans on denture plates.

Effects of glucose-induced insulin secretion on ST segment elevation in the Brugada syndrome

INTRODUCTION

ST segment elevation in patients with Brugada syndrome is known to fluctuate occasionally, influenced by multiple factors. Insulin has been shown to affect QT dispersion in healthy volunteers, as well as result in abnormality of ventricular repolarization in patients with congenital long QT syndrome.

METHODS AND RESULTS

To assess a possible role of insulin in ST segment elevation in patients with Brugada syndrome, an oral glucose tolerance test (OGTT) was administered to 20 patients with Brugada syndrome and 20 normal patients without ST-T changes as a control group. Plasma glucose and potassium levels, immunoreactive insulin concentration (IRI), and ST segment elevation and ST-T wave changes on 12-lead ECG during OGTT were analyzed. Augmentation (>1 mm) of ST elevation or morphologic changes in ST-T waves were observed frequently in response to increased IRI during OGTT [15/20 cases (75%)] in patients with Brugada syndrome but in none of the patients in the control group [0/20 cases (0%), P < 0.01]. The changes returned to baseline 180 minutes after the glucose load in 9 of 15 patients. Patients who showed coved-type ST elevation before the glucose load exhibited positive ECG changes more frequently than patients with saddleback-type elevation or transiently normalized ST segment [8/8 cases (100%) vs 7/12 (58%), P < 0.05]. There was no significant difference between the two groups in terms of glucose, IRI, and potassium levels during OGTT.

CONCLUSION

The findings suggest that glucose-induced insulin secretion is one of the contributing factors to fluctuation of ST segment elevation in patients with Brugada syndrome.

Skeletal abnormalities and ultrastructural changes of cartilage in transgenic mice expressing a collagen II gene (COL2A1) with a Cys for Arg-alpha1-519 substitution

OBJECTIVE

To examine the mechanism by which the Arg-->Cys 519 mutation causes the clinical phenotype employing transgenic mice that express the mutated human COL2A1.

METHODS

A DNA construct under the control of a COL2A1 specific promoter was prepared from genomic DNA isolated from fibroblasts from the proband with primary generalized osteoarthritis (OA) associated with a mild chondrodysplasia. Transgenic mice were obtained by injection of the constructs into pro-nuclei of fertilized eggs from the FVB/N inbred mouse strain. Transgenic mice harboring two alleles of the mutated human COL2A1 were examined for morphological abnormalities and for alterations of their skeletal development. Ultrastructural examination was performed to identify changes in the organization and density of collagen II fibrils in articular cartilage of the transgenic mice.

RESULTS

Transgenic mice harboring two alleles of the mutated human collagen gene were smaller than their normal littermates, had a cleft palate, and disorganized growth plate. Electron microscopy of articular cartilage showed a decreased density of collagen II fibrils and revealed chondrocytes with dilated Golgi cysternae.

CONCLUSIONS

Expression of a COL2A1 with an Arg-->Cys 519 substitution in transgenic mice causes retardation of skeletal development and ultrastructural alterations in articular cartilage with a profound reduction of the density of the collagen II fibrils in the tissue. These alterations may be responsible for the phenotype of precocious generalized OA and chondrodysplasia displayed by patients harboring this COL2A1 mutation.

Electronic structure of YbXCu(4) (X = In, Cd, Mg) investigated by high-resolution photoemission spectroscopy

The valence-band electronic structure of YbXCu(4) (X = In, Cd, Mg) has been investigated by means of temperature-dependent high-energy-resolution photoemission spectroscopy using a He I resonance line (hnu = 21.22 eV) and synchrotron radiation (hnu = 800 eV). Intensities of the structure due to the Yb(2+) 4f(7/2) states in the He I spectra of YbInCu(4) and YbCdCu(4) gradually increase with decreasing temperature from 300 to 10 K, and Yb(2+) 4f(7/2) structures are clearly observed as peaks near the Fermi level (E(F)) at 10 K. The enhancement of the Yb(2+) 4f(7/2) peak from 50 to 10 K is much greater for YbInCu(4) than for YbCdCu(4). On the other hand, the Yb(2+) 4f(7/2) states of YbMgCu(4) are observed as a broad structure near E(F). In the synchrotron radiation photoemission spectra of YbInCu(4) and YbCdCu(4), the structures due to the Yb(2+) and Yb(3+) 4f states are recognized at all temperatures. The intensity ratio Yb(2+)/Yb(3+) gradually increases with decreasing temperature. The energy separations between the Yb(2+) and Yb(3+) 4f structures of YbInCu(4) increase from 50 to 20 K. For YbMgCu(4), on the other hand, almost only the Yb(2+) structures are observed and little temperature dependence has been detected.

Opening of K(ATP) channel attenuates the increase in QT dispersion produced by the first balloon inflation during coronary angioplasty

Increased QT dispersion predicts the occurrence of lethal ventricular arrhythmias complicating percutaneous transluminal coronary angioplasty (PTCA). Moreover, these arrhythmias occur more frequently at the first balloon inflation. Activation of the K(ATP) channel may influence QT dispersion and ventricular arrhythmias during coronary angioplasty, so 40 consecutive patients with stable angina were randomized to receive 3 mg/h of nicorandil infusion or placebo and QT dispersion and the incidence of ventricular ectopy were investigated before and throughout PTCA. There were no significant differences in QT dispersion at baseline between the nicorandil group (42+/-8 ms) and placebo (42+/-12ms). At the first balloon inflation, the QT dispersion in the nicorandil group (51+/-13 ms) was significantly less than that observed with placebo (76+/-16ms, p<0.001). However, the QT dispersion at the second inflation was similar in both groups (nicorandil: 45+/-12ms; placebo: 52+/-14ms). Ventricular ectopy was observed in 1 patient receiving nicorandil and 5 patients in the placebo group during the first inflation, and none in the nicorandil and 1 patient in the placebo group during the second balloon inflation. Activation of the K(ATP) channel may inhibit the development of ventricular arrhythmias during PTCA, particularly at the first balloon inflation.

Absence of Z-chromosome inactivation for five genes in male chickens

In order to examine if Z-chromosome inactivation, which is analogous to X-chromosome inactivation in mammals, takes place in male birds having ZZ sex chromosomes, five Z-linked genes of chickens which are expressed in both sexes in certain tissues were selected: i.e. genes for growth hormone receptor, nicotinic acetylcholine receptor beta3, aldolase B, beta1,4-galactosyltransferase I, and iron-responsive element-binding protein (also known as cytosolic aconitase). Antisense or sense riboprobe was prepared from an intronic sequence of each gene and subjected to fluorescence in situ hybridization to nascent transcripts of each gene in a nucleus. Each antisense riboprobe hyridized to two spots of nascent RNA which corresponded to its gene loci on the two Z chromosomes in a majority of nuclei in a tissue of the male. The efficiency of detection of two spots per nucleus was comparable to that for the glyceraldehyde-3-phosphate dehydrogenase gene, an autosomal housekeeping gene. These results suggest strongly that Z-chromosome inactivation, i.e. virtual silence of transcription at one of the alleles, does not take place for these five Z-linked genes in male chickens.

Effects of glucose-induced insulin secretion on ventricular repolarization in patients with congenital long QT syndrome

To assess the role of insulin in ventricular repolarization in patients with congenital long QT syndrome (LQTS), an oral glucose tolerance (OGT) test was performed in 11 patients with LQTS and in 11 control cases without QT prolongation. Plasma glucose, potassium level and the immunoreactive insulin concentration (IRI) were measured, and the QT interval and T wave morphology on 12-lead ECG were analyzed during fasting and after glucose load. The LQTS group had a higher incidence of changes in T wave morphology, such as biphasic, bifid or notched T wave, after glucose load than the control group (11 of 11 patients [100%] vs 0 of 11 [0%]; p<0.00001). The T wave changes returned to baseline at 180 min after glucose load in 7 patients. The maximal QT interval and QT dispersion increased significantly and returned to baseline level in response to IRI after glucose load in LQTS, whereas the QT interval was unaffected in the control group. After glucose load, ventricular arrhythmias and T wave alternans were observed in 3 and 1 patients with LQTS, respectively, but none in the control group. The findings suggest that glucose-induced insulin secretion plays a role in inducing abnormalities and inhomogeneity of ventricular repolarization in patients with LQTS.

Delayed-onset ataxia in mice lacking alpha -tocopherol transfer protein: model for neuronal degeneration caused by chronic oxidative stress

alpha-Tocopherol transfer protein (alpha-TTP) maintains the concentration of serum alpha-tocopherol (vitamin E), one of the most potent fat-soluble antioxidants, by facilitating alpha-tocopherol export from the liver. Mutations of the alpha-TTP gene are linked to ataxia with isolated vitamin E deficiency (AVED). We produced a model mouse of AVED by deleting the alpha-TTP gene, which showed ataxia and retinal degeneration after 1 year of age. Because the brain alpha-TTP functions in maintaining alpha-tocopherol levels in the brain, alpha-tocopherol was completely depleted in the alpha-TTP(-/-) mouse brain, and the neurological phenotype of alpha-TTP(-/-) mice is much more severe than that of wild-type mice when maintained on an alpha-tocopherol-deficient diet. Lipid peroxidation in alpha-TTP(-/-) mice brains showed a significant increase, especially in degenerating neurons. alpha-Tocopherol supplementation suppressed lipid peroxidation and almost completely prevented the development of neurological symptoms. This therapy almost completely corrects the abnormalities in a mouse model of human neurodegenerative disease. Moreover, alpha-TTP(-/-) mice may prove to be excellent animal models of delayed onset, slowly progressive neuronal degeneration caused by chronic oxidative stress.

Premature vertebral endplate ossification and mild disc degeneration in mice after inactivation of one allele belonging to the Col2a1 gene for Type II collagen

STUDY DESIGN

Skeletal tissues of mice with an inactivated allele of the Col2a1 gene for Type II collagen ("heterozygous knockout") were studied.

OBJECTIVE

To determine whether a heterozygous inactivation of the Col2a1 gene has a role in the etiology of spine disorders such as disc degeneration.

SUMMARY OF BACKGROUND DATA

Mutations in the COL2A1, COL11A1, COL11A2, and COL9A2 genes have been linked to spine disorders. However, the mechanism by which genetic factors lead to disc degeneration still are largely unknown.

METHODS

Spine tissues were studied using radiograph analyses; conventional, quantitative, and polarized light microscopy; immunohistochemistry for the major extracellular components, and in situ hybridization for procollagens alpha1(I) and alpha1(II). Voluntary running activity also was monitored in half of the mice.

RESULTS

As the findings showed, 1-month-old heterozygous knockout mice had shorter limb bones, skulls, and spines, as well as thicker and more irregular vertebral endplates, which calcified earlier than in the control mice. They also had a lower concentration of glycosaminoglycans in the anulus fibrosus, in the endplates, and in the vertebral bone than the controls. These features in the heterozygous knockout mice were compensated by the age of 15 months. However, the long bones and skulls of the mature heterozygous mice remained shorter than those of the controls. Gene-deficient mice used the running wheel less. However, physical exercise did not induce any marked structural changes in the skeleton.

CONCLUSION

Mice with heterozygous knockout of Col2a1 show subtle early skeletal manifestations that bear some resemblance to those of human spine disorders.