No evidence for involvement of the calpain-10 gene 'high-risk' haplotype combination for non-insulin-dependent diabetes mellitus in early onset obesity

In light of evidence of linkage of obesity to chromosome 2q31-q37, we hypothesized that the calpain-10 gene 'high-risk' haplotype combination for non-insulin-dependent diabetes mellitus (NIDDM) is involved in early onset obesity. We screened the NIDDM 'high-risk'-haplotype combination formed by the alleles 112 and 121 of the polymorphisms UCSNP-43, -19, and -63 in 166 families consisting of an extremely obese child or adolescent (mean BMI percentile: 99.3+/-1.38), one or more obese sibs (mean BMI percentile: 97.42+/-2.88), and both of their parents. Genotyping for three calpain-10 gene polymorphisms was performed by polymerase chain reaction (PCR) with (a) length polymorphism detection (UCSNP-19) or (b) allele-specific PCR (UCSNP-43 and -63). To allow for correct haplotype assignment all individuals were additionally genotyped for two microsatellite markers (D2S125 and D2S2338). We followed a hierarchical test procedure. As the first step, model-free linkage analysis was performed using maximum likelihood binomial statistics. The second stage consisted of a one-sided asymptotic pedigree disequilibrium test for the UCSNP-43 and on an exploratory level for the other SNP-markers and all haplotypes formed by the three SNPs. The final stage investigated the reported haplotype combination. We failed to detect an initial linkage of obesity to this region (LOD score <0.4). All subsequent exploratory analyses were negative. Our analysis of the relationship between the NIDDM 'high-risk' haplotype combination and extreme early onset obesity revealed no evidence for linkage and association.     

Multicontrast MRI of remyelination in the central nervous system

Although magnetic resonance imaging (MRI) represents the most sensitive tool for the detection of white matter abnormalities in patients with multiple sclerosis (MS), the heterogeneity of MS placques severely hampers the elucidation of specific pathophysiological processes. In order to identify putative MRI markers for de- and remyelination, we employed the cuprizone mouse model which leads to a selective and reversible demyelination of the corpus callosum with little or no axonal damage. Apart from histopathology, animals were studied with high-resolution three-dimensional MRI in vivo using multiple contrasts. While individual MRI findings significantly correlated with electron microscopy, the differentiation of regions with normal, demyelinated or remyelinated white matter by one contrast alone was less specific than by histology or electron microscopy. However, an accurate MRI prediction of the in vivo myelin status was achieved by a discriminant function analysis using a combination of T1, T2 and magnetization transfer contrast. With a correct assignment of 95% of all animals examined, the procedure will allow for the survey of new therapeutic approaches aiming at improved remyelination.     

Heinzkörperchen und Blutfarbstoff

Zusammenfassung Heinzsche Körperchen, Methämoglobin und Sulfhämoglobin sind drei verschiedene, voneinander unabhängige und nebeneinander herlaufende Folgen gewisser Vergiftungen.Statt Methämoglobin empfiehlt sich als besserer Ausdruck: Häimglobin, statt Sulfhämoglobin Verdoglobin. Der Ausdruck hämoglobinämische Innenkörperchen entspricht in keiner Hinsicht dem tatsächlichen Befunde und ist daher auszumerzen.     

Administration of transforming growth factor-alpha enhances anatomical and behavioral recovery following olfactory nerve transection

Although replacement of olfactory receptor neurons (ORNs) and subsequent reinnervation of the olfactory bulb occur following ORN injury, the intrinsic and extrinsic factors that contribute to the regulation of this dynamic process have not yet been fully identified. Recent research indicates that several growth factors have neurogenic effects on ORNs in vitro, and that chronic in vivo administration of either basic fibroblast growth factor, epidermal growth factor, or transforming growth factor-alpha (TGF-alpha) following chemical lesion can enhance the normal rate of ORN reinnervation of the olfactory bulb. The primary goal of the present experiments was to further assess the extent to which growth factor-related enhancements in the rate of anatomical recovery during ORN reconstitution and subsequent reinnervation of olfactory bulb are accompanied by enhancements in the rate of recovery of odor-guided behavior.A series of experiments in rats was conducted to initially characterize the time course of the anatomical and behavioral recovery normally observed following ORN reconstitution as a consequence of olfactory nerve transection, and to subsequently characterize the anatomical and behavioral effects of TGF-alpha administration on this normal rate of recovery. Consistent with a host of prior studies, olfactory nerve transection produced consistent and substantial deafferentation of olfactory bulb followed by a time-dependent anatomical recovery which was significantly enhanced by administration of TGF-alpha. The effect of TGF-alpha on functional recovery following olfactory nerve transection was also assessed using an odor-guided fear conditioning task. ORN lesioned animals receiving injections of TGF-alpha during recovery were found to display enhanced conditioned responding to an olfactory stimulus compared to untreated subjects. Further behavioral analyses suggested that this enhanced functional recovery was likely not due to non-specific effects of TGF-alpha on cognition or motor activity, but rather to enhanced olfactory input to the CNS.Future studies will likely reveal the exact mechanism of action mediating the anatomical and concomitant behavioral effects of this growth factor. Since ORNs are one of only a few populations of neurons capable of regeneration or replacement, the continued study of the cellular and molecular factors that coordinate this regenerative process may ultimately lead to the development of therapeutic strategies to promote an enhanced functional recovery following injury to other neuronal populations.     

Specificity of in vitro reconstitution of bromegrass mosaic virus

Bromegrass mosaic virus (BMV) RNA was allowed to compete with yeast tRNA or alfalfa mosaic virus (AMV) RNA for in vitro encapsidation by BMV protein. Various proportions of 32P-labeled foreign RNAs were added to a reassembly mixture (BMV protein: BMV RNA, 4:1) and the reassembly products were observed by analytical and rate-zonal sedimentation, and the RNA contents of the nucleocapsids were examined by gel electrophoresis. Incubation of BMV protein with tRNA alone produced 56 S particles containing five or six tRNA molecules per particle, but with both tRNA and BMV RNA present very little of the tRNA was incorporated. AMV 12 S RNA led to 64 S particles containing one AMV RNA molecule: with both AMV and BMV RNAs present, the smallest BMV RNA outcompeted the AMV RNA about fourfold, even though the two RNAs have similar molecular weights and biological functions. Evidently BMV protein does to some extent specifically recognise its own RNA molecules.     

Prolongation of small bowel allograft survival with a sequential therapy consisting of a synthetic MHC class II peptide and temporarily low-dose cyclosporine A

It has been extensively documented the role of the indirect pathway of allorecognition in allograft rejection. However, recent data demonstrate that the manipulation of this pathway could be also sufficient to promote prolongation of allograft survival. In the present study we evaluated the effect of preoperative immunization with the WF-specific MHC class II peptides RT1.D2 and RT1.B2 in combination with low-dose CsA from days 0 to 7 (5 mg/kg/day) and from days 8 to 30 (1 mg/kg/day) after WF small bowel transplantation. Seven days before and on the day of transplantation, LEW recipients were immunized with the two WF MHC class II peptides RT1.B2 and RT1.D2. The CsA monotherapy induced an allograft survival of 49.3 +/- 6.1 days. MHC class II peptide immunization had a limited effect on allograft survival for RT1.D2 (47.1 +/- 3.8 days) and induced prolongation of allograft survival for RT1.B2 (73.6 +/- 34.6 days). This effect seems to be based on the absence or silence of RT1.B2-reactive T cells and rejection seems to be correlated with the presence of RT1.B2-specific T cells in the late phase. Therefore, the combination of RT1.B2 with low-dose CsA shifts the immunological response and protects small bowel allograft rejection.     

Calmodulin permanently associates with rat olfactory CNG channels under native conditions

An important mechanism by which vertebrate olfactory sensory neurons rapidly adapt to odorants is feedback modulation of the Ca(2+)-permeable cyclic nucleotide-gated (CNG) transduction channels. Extensive heterologous studies of homomeric CNGA2 channels have led to a molecular model of channel modulation based on the binding of calcium-calmodulin to a site on the cytoplasmic amino terminus of CNGA2. Native rat olfactory CNG channels, however, are heteromeric complexes of three homologous but distinct subunits. Notably, in heteromeric channels, we found no role for CNGA2 in feedback modulation. Instead, an IQ-type calmodulin-binding site on CNGB1b and a similar but previously unidentified site on CNGA4 are necessary and sufficient. These sites seem to confer binding of Ca(2+)-free calmodulin (apocalmodulin), which is then poised to trigger inhibition of native channels in the presence of Ca(2+).     

Advanced 1H Solid‐State NMR Spectroscopy on Hydrogels, 1

Summary: The nature of the pH dependent collapse of poly(methacrylic acid) (PMAA) hydrogels is investigated using recent ¹H solid‐state NMR methods. In aqueous solution, PMAA changes from an expanded conformation at high pHs to a compact contracted form at low pHs, where hydrogen bonds play a central role. In solid‐state ¹H NMR spectra, recorded under fast magic angle spinning (MAS), dried PMAA samples previously collapsed at low pHs show characteristic signals in the spectral region of the carboxylic acid protons. With the aid of 2D ¹H‐¹H double‐quantum (DQ) MAS NMR spectra, three signals can be distinguished at 8, 10.5 and 12.5 ppm, which are attributed to free carboxylic groups and two different types of hydrogen bonded forms, respectively. The 12.5 ppm signal arises from the hydrogen bond with the shortest H? H distance, corresponding to the form that is most stable with respect to increasing temperature and pH. The weaker hydrogen‐bonded form (with a signal at 10.5 ppm) requires a slightly lower pH, while the free acid signal (at 8 ppm) emerges under the most acidic medium. Moreover, the stabilities of the hydrogen‐bonded carboxylic acid dimers can be inferred from the proton‐proton distances within the dimers, i.e. (275 ± 5) pm and (295 ± 15) pm for the protons at 12.5 and 10.5 ppm, respectively, which are determined by means of DQ MAS sideband patterns. Both the stability of the hydrogen bonds and the acidity of the protons may be related to the stereochemistry and the conformation of the PMAA chains.

     

Molecular analysis of streptogramin resistance in enterococci

The new semi-synthetic streptogramin antibiotic combination quinupristin/dalfopristin (Synercid) is a promising alternative for a treatment of infections with multiple resistant gram-positive pathogens, e.g. glycopeptide- and multi-resistant Enterococcus faecium. Streptogramins consist of two unrelated compounds, a streptogramin A and B, which act synergistically when given in combination. Mechanisms conferring resistance against both components are essential for resistance against the combination in E. faecium. In this species resistance to streptogramin A compounds is mediated via related acetyltransferases VatD and VatE. Resistance against streptogramins B is either encoded by the widespread ermB gene cluster conferring resistance to macrolide-lincosamide-streptogramin B antibiotics or via expression of the vgbA gene, which encodes a staphylococcal-type lactonase. E. faecalis is intrinsically resistant to streptogramins. Due to a wide use of streptogramins (virginiamycins S/M) in commercial animal farming a reservoir of streptogramin-resistant E. faecium isolates had already been selected. Determinants for streptogramin resistance are localized on plasmids that can be transferred into an E. faecium recipient both in vitro in filter-matings and in vivo in the digestive tracts of rats. Hybridization and sequencing experiments revealed a linkage of resistance determinants for streptogramins A and B on definite plasmid fragments.