COMPLEMENT-MEDIATED ADIPOCYTE LYSIS BY NEPHRITIC FACTOR SERA

Recent data indicate a previously unsuspected link between the complement system and adipocyte biology. Murine adipocytes produce key components of the alternative pathway of complement and are able to activate this pathway. This suggested to us an explanation for adipose tissue loss in partial lipodystrophy, a rare human condition usually associated with the immunoglobulin G(IgG) autoantibody nephritic factor (NeF) which leads to enhanced alternative pathway activation in vivo. We hypothesized that in the presence of NeF, there is dysregulated complement activation at the membrane of the adipocyte, leading to adipocyte lysis. Here we show that adipocytes explanted from rat epididymal fat pads are lysed by NeF-containing sera but not by control sera. A similar pattern is seen with IgG fractions of these sera. Adipocyte lysis in the presence of NeF is associated with the generation of fluid-phase terminal complement complexes, the level of which correlates closely with the level of lactate dehydrogenase, a marker of cell lysis. Lysis is abolished by ethylenediaminetetraacetic acid, which chelates divalent cations and prevents complement activation, and reduced by an antibody to factor D, a key component of the alternative pathway. These data provide an explanation for the previously obscure link between NeF and fat cell damage

Paraprotein-related renal disease

Paraprotein-related renal disease represents a diverse group of rare diseases characterized by distinct renal injury caused by the direct or indirect effects of a nephrotoxic paraprotein secreted by a clone of B cells. Early diagnosis and use of rapidly effective chemotherapy agents have improved patient and renal outcomes for these disorders. Patients can present with proteinuric renal impairment or tubular dysfunction. Diagnosis is often challenging because of the wide range of disease manifestations, difficulties with detection of the pathogenic clone and the common finding of an incidental paraprotein in elderly individuals. A renal biopsy along with haematological work-up is required to link a paraprotein with kidney disease. Chemotherapy directed at the plasma cell clone can halt the production of the paraprotein, which can in turn benefit renal function

Is it really search or just matching? The influence of goodness, number of stimuli and presentation sequence in same-different tasks

The Goodness of Garner dot patterns has been shown to influence same-different response times in a specific way, which has led to the formulation of a memory search model of pattern comparison. In this model, the space of possible variations of each pattern is searched separately for each pattern in the comparison, resulting in faster response times for patterns that have fewer alternatives. Compared to an alternative explanation based on stimulus encoding plus mental rotation, however, the existing data strongly favor this explanation. To obtain a more constraining set of data to distinguish between the two possible accounts, we extended the original paradigm to a situation in which participants needed to compare three, rather than two patterns and varied the way the stimuli were presented (simultaneously or sequentially). Our findings suggest that neither the memory search nor the encoding plus mental rotation model provides a complete description of the data, and that the effects of Goodness must be understood in a combination of both mechanisms, or in terms of cascades processing

A Standard Protocol for the Calibration of Capillary Electrophoresis (CE) Equipment

Calibration of complex analytical systems is always a difficult task. Nevertheless, a suitable approach has to be designed before the systems can be introduced into routine analysis. In literature, many methods have been described for the purpose of calibrating such systems, but only a few of them deal with capillary elctrophoresis. Here, we want to demonstrate a general approach to how the calibration of this type of analytical instrument becomes feasible

Content of flavan-3-ol monomers and gallic acid in grape seeds by variety and year

The content of flavan-3-ol monomers and gallic acid in grape seeds in the samples from the gene collection of Viticulture Research Station Karlštejn (Czech Republic) was investigated. Presence of catechin, epicatechin, epigallocatechin, epicatechin gallate and gallic acid was confirmed in these samples, other flavan-3-ol monomers like gallocatechin or epigallocatechin gallate were below limit of detection. As major flavan-3-ol monomers catechin and epicatechin with 85 % were detected. Average content of catechin in grape seed was 4454 ± 148 µg·g-1, 3085 ± 98 µg·g-1 epicatechin, 600 ± 41 µg·g-1 epigallocatechin, 457 ± 19 µg·g-1 gallic acid, and 352 ± 16 µg·g-1 epicatechin gallate. Variety had main impact on phenolic content followed by vintage. Average sum of flavan-3-ol monomers in grape seeds in white varietes was 7601 ± 273 µg·g-1 and 10869 ± 430 µg·g-1 in red varieties, with 10050 ± 425 µg·g-1 in 2012 and 7846 ± 219 µg·g-1 in 2013 were found on average in all varieties, respectively.  The highest phenolic content was characteristic for 'Pinot Noir', 'Muskat Donskoi', 'Aromriesling' and 'Hibernal' and may contribute to their health properties

The Kinetics of the Silver(i)-induced Oxidation of Chromium(iii) by Peroxodisulphate

Chromium(III) and chromium(VI) compounds play an important role in natural oxidation processes in terrestrial and atmospheric water. During the oxidation of SO2, peroxodisulphate is formed as an intermediate. In acidic and neutral solutions, peroxodisulphate oxidizes chromium(III) very slowly. This reaction rate is markedly enhanced by silver ions, resulting in a reaction rate that allows the reaction to be studied conveniently under laboratory conditions. The kinetics of the Cr(III)/Ag(I)/S2O82– reaction system were studied as a function of different Cr(III), Ag(I) and S2O82– concentrations, temperature and pressure. The formation of Cr(VI) was observed as a first-order process at high [Cr(III)] and as a zero-order process at low [Cr(III)].Aninduction period was observed in both cases. For the first-order process, reaction rates were found to be independent of [Cr(III)], linearly dependent on [Ag+] and independent of [S2O82–]. The activation enthalpy (ΔH≠) was calculated as 56 ± 5 kJ mol–1, the activation entropy (ΔS≠) as –136 ± 16 J K–1 mol–1 and the activation volume as –5.8 ± 0.7 cm3 mol–1. At low [Cr(III)], the reaction rate was independent of [Cr(III)], linearly dependent on [S2O82–] and non-linearly dependent on [Ag+], reaching a limiting value at high [Ag+]. The activation enthalpy (ΔH≠) was calculated as 61±5kJmol–1, the activation entropy (ΔS≠) as –119±15 J K–1 mol–1 and the activation volume as –1.7±0.1 cm3 mol–1. A mechanism involving the reversible formation of a silver-peroxodisulphate complex that decomposes into oxidizing intermediates is proposed. The empirical observations can be adequately described by this mechanism.Keywords: Chromium(III), peroxodisulphate, oxidation, silver

Ammonia: what adult neurologists need to know

Hyperammonaemia is often encountered in acute neurology and can be the cause of acute or chronic neurological symptoms. Patients with hyperammonaemia may present with seizures or encephalopathy, or may be entirely asymptomatic. The underlying causes are diverse but often straightforward to diagnose, although sometimes require specialist investigations. Haemodialysis or haemo(dia)filtration is the first-line treatment for acute severe hyperammonaemia (of any cause) in an adult. Here we discuss our approach to adult patients with hyperammonaemia identified by a neurologist