Subclass IgG to motor gangliosides related to infection and clinical course in Guillain-Barré syndrome

In 176 patients with Guillain-Barré syndrome the subclass and cross-reactivity of serum IgG antibodies to motor gangliosides was related to preceding infections and clinical phenotypes. Two subgroups of patients were identified. Presence of only IgG1 antibodies was related to diarrhea, positive Campylobacter serology, cross-reactive antibodies to C. jejuni lipo-oligosaccharides and poor outcome. In contrast, having both IgG1 and IgG3 antibodies was related to upper respiratory tract infections, cross-reactive antibodies to Haemophilus influenzae lipo-oligosaccharides and better outcome. These findings support a model in which C. jejuni and H. influenzae infections induce two distinct patterns of cross-reactive antibodies with different clinical outcome.     

Total ganglioside ablation at mouse motor nerve terminals alters neurotransmitter release level

Neuronal membrane gangliosides, forming a large family of sialylated glycosphingolipids, have been hypothesized to play important roles in synaptic transmission. We studied the ex vivo electrophysiological function of neuromuscular junctions of GM2/GD2‐synthase*GD3‐synthase compound null‐mutant mice after acute removal of GM3, the only remaining ganglioside in this mouse, by in vitro treatment with neuraminidase. We found 16% enhancement of the acetylcholine release per nerve impulse at low‐rate (0.3 Hz) nerve stimulation. Conversely, the treatment reduced the acetylcholine release evoked by high‐rate (40 Hz) nerve stimulation. Also, 25 ms paired‐pulse facilitation of endplate potentials was reduced by the neuraminidase‐treatment. These effects may indicate a modest modulatory influence of the negative electrical charges carried by the sialic acid molecules of gangliosides on the function of presynaptic Ca_v2.1 channels, affecting the magnitude and kinetics of the Ca²⁺ influx that induces neurotransmitter release from the motor nerve terminal. Our results show that gangliosides are to some extent involved in neurotransmission at the neuromuscular junction, but that their presence is not an absolute requirement in this process. Synapse 64:335–338, 2010. © 2009 Wiley‐Liss, Inc.     

Ubiquitous Water-Soluble Molecules in Aquatic Plant Exudates Determine Specific Insect Attraction

Plants produce semio-chemicals that directly influence insect attraction and/or repulsion. Generally, this attraction is closely associated with herbivory and has been studied mainly under atmospheric conditions. On the other hand, the relationship between aquatic plants and insects has been little studied. To determine whether the roots of aquatic macrophytes release attractive chemical mixtures into the water, we studied the behaviour of mosquito larvae using olfactory experiments with root exudates. After testing the attraction on Culex and Aedes mosquito larvae, we chose to work with Coquillettidia species, which have a complex behaviour in nature and need to be attached to plant roots in order to obtain oxygen. This relationship is non-destructive and can be described as commensal behaviour. Commonly found compounds seemed to be involved in insect attraction since root exudates from different plants were all attractive. Moreover, chemical analysis allowed us to identify a certain number of commonly found, highly water-soluble, low-molecular-weight compounds, several of which (glycerol, uracil, thymine, uridine, thymidine) were able to induce attraction when tested individually but at concentrations substantially higher than those found in nature. However, our principal findings demonstrated that these compounds appeared to act synergistically, since a mixture of these five compounds attracted larvae at natural concentrations (0.7 nM glycerol, <0.5 nM uracil, 0.6 nM thymine, 2.8 nM uridine, 86 nM thymidine), much lower than those found for each compound tested individually. These results provide strong evidence that a mixture of polyols (glycerol), pyrimidines (uracil, thymine), and nucleosides (uridine, thymidine) functions as an efficient attractive signal in nature for Coquillettidia larvae. We therefore show for the first time, that such commonly found compounds may play an important role in plant-insect relationships in aquatic eco-systems.     

Hospitalization and emergency department visits among seniors receiving homecare: a pilot study

Background

The objective of this study was to examine the Minimum Data Set (MDS) and Geriatric Depression Scale (GDS) as measures of depression among nursing home residents.

Methods

The data for this study were baseline, pre-intervention assessment data from a research study involving nine nursing homes and 704 residents in Massachusetts. Trained research nurses assessed residents using the MDS and the GDS 15-item version. Demographic, psychiatric, and cognitive data were obtained using the MDS. Level of depression was operationalized as: (1) a sum of the MDS Depression items; (2) the MDS Depression Rating Scale; (3) the 15-item GDS; and (4) the five-item GDS. We compared missing data, floor effects, means, internal consistency reliability, scale score correlation, and ability to identify residents with conspicuous depression (chart diagnosis or use of antidepressant) across cognitive impairment strata.

Results

The GDS and MDS Depression scales were uncorrelated. Nevertheless, both MDS and GDS measures demonstrated adequate internal consistency reliability. The MDS suggested greater depression among those with cognitive impairment, whereas the GDS suggested a more severe depression among those with better cognitive functioning. The GDS was limited by missing data; the DRS by a larger floor effect. The DRS was more strongly correlated with conspicuous depression, but only among those with cognitive impairment.

Conclusions

The MDS Depression items and GDS identify different elements of depression. This may be due to differences in the manifest symptom content and/or the self-report nature of the GDS versus the observer-rated MDS. Our findings suggest that the GDS and the MDS are not interchangeable measures of depression.     

α-干扰素加软坚散结汤抗慢性乙型肝炎肝纤维化及早期肝硬化的临床研究

目的:探讨慢性乙型肝炎肝纤维化及早期肝硬化的中西医结合疗法。方法:采用α-干扰素加中药软坚散结汤联合治疗经病理确诊的慢性乙型肝炎患者62例,并以同期64例慢性乙肝患者作对照,疗程均为6个月。结果:治疗组临床症状及体征明显改善,血清ALT、TBil、A/G、γ球蛋白(γ-GT)和肝纤维化指标水平明显降低,血清白蛋白(A)水平有不同程度升高(P<0.01或0.05);B超示肝内光点粗、Ⅲ级血管走行欠清和分布不均等异常声像图明显改善,与对照组比较差异有显著性意义(P<0.05)。此外,治疗组HBeAg转阴率为61.0％,明显优于对照组36.3％(P<0.01)。结论:α-扰素和中药软坚散结汤联合应用,对改善慢性乙型肝炎患者临床症状体征,促进肝功能复常,抗肝纤维增生和抑制乙肝病复制等有显著疗效。     

Mouse monoclonal and rabbit polyclonal antibodies prepared to human myelin-associated glycoprotein also react with glycosphingolipids of peripheral nerve

A panel of mouse monoclonal antibodies and rabbit polyclonal antisera that were raised to myelin-associated glycoprotein (MAG) were screened for reactivity with acidic glycolipids from brain and peripheral nerve by enzyme-linked immunosorbent assay (ELISA) and/or a thin-layer chromatogram overlay technique. Seven out of 7 mouse monoclonal antibodies that recognize carbohydrate epitopes in human MAG also reacted with acidic glycolipids from human and cat peripheral nerve, while monoclonal antibodies that react with polypeptide epitopes on MAG did not react with these glycolipids. Rabbit anti-human MAG antisera also strongly reacted with the glycolipids from peripheral nerve, while rabbit antisera raised to rat MAG did not. None of the antibodies reacted with similar glycolipid fractions prepared from adult human brain. Overlay of thin-layer chromatograms revealed that all the mouse and rabbit antibodies showing reactivity with peripheral nerve glycolipids were binding to the same two sphingoglycolipids that react with human anti-MAG IgM paraproteins in neuropathy and with HNK-1 (anti-Leu-7), a mouse IgM monoclonal antibody that identifies a subset of human lymphocytes with natural killer function. Thus, the carbohydrate epitope(s) in MAG which is shared with nerve acidic glycolipids appears to be highly immunogenic in mice and rabbits. Further, it is clear that the antibodies that react with the carbohydrate moieties of human MAG cannot be used as specific probes for this glycoprotein.