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Notes: Reduced activity of the mitochondrial respiratory chain – particularly complex I – may be implicated in the etiology of both Parkinson's disease and progressive supranuclear palsy, although these neurodegenerative diseases differ substantially as to their distinctive pattern of neuronal cell loss and the predominance of cerebral α-synuclein or tau protein pathology. To determine experimentally whether chronic generalized complex I inhibition has an effect on the distribution of α-synuclein or tau, we infused rats systemically with the plant-derived isoflavonoid rotenone. Rotenone-treated rats with a pronounced metabolic impairment had reduced locomotor activity, dystonic limb posture and postural instability. They lost neurons in the substantia nigra and in the striatum. Spherical deposits of α-synuclein were observed in a few cells, but cells with abnormal cytoplasmic accumulations of tau immunoreactivity were significantly more numerous in the striatum of severely lesioned rats. Abnormally high levels of tau immunoreactivity were found in the cytoplasm of neurons, oligodendrocytes and astrocytes. Ultrastructurally, tau-immunoreactive material consisted of straight 15-nm filaments decorated by antibodies against phosphorylated tau. Many tau+ cell bodies also stained positive for thioflavin S, nitrotyrosine and ubiquitin. Some cells with abnormal tau immunoreactivity contained activated caspase 3. Our data suggest that chronic respiratory chain dysfunction might trigger a form of neurodegeneration in which accumulation of hyperphosphorylated tau protein predominates over deposits of α-synuclein.

Notes: The aetiology of schizophrenia is complex and the pathological mechanisms involved are still not fully understood. The aim of this project was to gain insight into the underlying molecular changes occurring in schizophrenia through the analysis of gene expression. Using suppression subtractive hybridization to isolate differentially expressed genes in superior temporal cortex (BA22), we detected one prominent sequence with reduced expression in schizophrenia and represented in at least nine clones. This was then selected for further validation. This 190-bp partial transcript showed identity to part of the Dickkopf-3 (Dkk3) gene sequence. Differential expression was initially confirmed in BA22 by slot blot hybridization where expression was decreased by 35% (p 〈 0.026). These results were further authenticated in a larger panel (12 control and 11 schizophrenia cases) using SYBR Green I real-time quantitative RT–PCR, in which a 41% decrease in expression of Dkk3 mRNA in schizophrenia was obtained (p 〈 0.012). Furthermore, using in situ hybridization, Dkk3 mRNA was shown to be abundantly expressed in cortical neurones, with prominent expression in layers II/III and V/VI of BA22. Dkk3 belongs to a novel family of Dkk proteins, which have been shown to be potent inhibitors of the neurodevelopmental wingless (Wnt) signalling pathway, and is therefore a putative candidate for further investigation into the aetiology of schizophrenia.

Notes: There is evidence that an inflammatory microglial reaction participates in the pathophysiology of dopaminergic neuronal death in Parkinson's disease and in animal models of the disease. However, this phenomenon remains incompletely characterized. Using an in vitro model of neuronal/glial mesencephalic cultures, we show that the dopaminergic neurotoxin 1-methyl-4-phenylpyridinium (MPP+) stimulates the proliferation of microglial cells at concentrations that selectively reduce the survival of DA neurones. The mitogenic action of MPP+ was not the mere consequence of neuronal cell demise as the toxin produced the same effect in a model system of neuronal/glial cortical cultures, where target DA neurones are absent. Consistent with this observation, the proliferative effect of MPP+ was also detectable in neurone-free microglial/astroglial cultures. It disappeared, however, when MPP+ was added to pure microglial cell cultures suggesting that astrocytes played a key role in the mitogenic mechanism. Accordingly, the proliferation of microglial cells in response to MPP+ treatment was mimicked by granulocyte macrophage colony-stimulating factor (GM-CSF), a proinflammatory cytokine produced by astrocytes and was blocked by a neutralizing antibody to GM-CSF. Thus, we conclude that the microglial reaction observed following MPP+ exposure depends on astrocytic factors, e.g. GM-CSF, a finding that may have therapeutic implications.

Notes: Serum procalcitonin (PCT), an accurate marker of severe infection, is moderately increased in chronic kidney disease (CKD), peritoneal dialysis (PD) and haemodialysis (HD). We studied the extent of PCT elevation and factors accounting for elevated PCT in CKD and dialysis, and whether peripheral blood mononuclear cells (PBMC) contribute to increased PCT. In 37 controls, 281 CKD, 31 PD, and 65 HD patients without infection, PCT was measured and correlated with CKD stage, PD, HD, C-reactive protein (CRP), cardiovascular disease (CVD) and other clinical parameters. PCT release by PBMC from controls, advanced CKD, PD and HD patients (12 subjects each) was measured. PCT increased in parallel to the deterioration of CKD. Oliguria, advanced CKD, PD, HD, CVD and elevated CRP were independently associated with PCT elevation. PCT release from PBMC significantly increased in advanced CKD, PD and HD. PCT release from PBMC correlated closely with the corresponding serum PCT values (r = 0.76, P 〈 0.001). In the absence of infection, PCT may increase due to reduced renal elimination and increased synthesis, as due to PBMC. Furthermore, serum PCT could serve as a marker of low-grade inflammation and CVD, which substantially increase mortality in CKD and dialysis.

Notes: Biologically active transforming growth factor beta 1 (TGFβ1) has been identified at sites of Mycobacterium tuberculosis (MTB) infection in the lung; however, the underlying mechanism(s) for its activation is not clear. Here using an enzyme-linked immunospot assay for TGFβ1, we show that human blood monocytes (MN) and alveolar macrophages (AM) produce bioactive TGFβ1 upon stimulation by MTB. However, only MTB-stimulated MN increased TGFβ1 production on a per cell basis. The frequency of TGFβ1-producing MN was reduced by an inhibitor of plasmin, bdellin, indicating a role for plasmin pathways in the bioactivation of cytokine. The expression of urokinase plasminogen activator receptor (uPAR) mRNA and both surface and soluble uPAR (CD87) was increased in MTB-activated MN. However, antibody neutralization of uPAR suppressed bioactive TGFβ1 in MN alone. Thus, the more immature MN, which are continuously recruited to the lung during tuberculosis (TB), have a higher capacity to bioactivate TGFβ1 by expression of components of the plasmin pathway. Excess production and bioactivation of TGFβ1 at sites of MTB infection may undermine host immune responses during TB.

Notes: Variant Creutzfeldt-Jakob disease (vCJD) is associated with extensive prion infection of lymphoreticular tissues during the prolonged asymptomatic incubation period. Instruments exposed to infected tissues of preclinically infected individuals during medical or surgical procedures represent a potential risk of iatrogenic transmission of vCJD prions. We assessed the frequency of contamination with lymphoid tissue of single-use laryngoscope blades used for tracheal intubation for general anaesthesia. Using a cyto-centrifugation technique, lymphocytes were detected from 30% of laryngoscope blades studied. As prions resist routine sterilisation procedures, the use of non-disposable laryngoscope blades poses a risk of transmitting vCJD from patient to patient. The use of such instruments should be abandoned and disposable alternatives used.

Notes: Subarachnoid haemorrhage is a common neurological emergency, which carries a high morbidity and mortality. It is usually caused by rupture of an intracerebral aneurysm or, less commonly, an arteriovenous malformation. Although most patients present to a non-neurosurgical hospital, they often require urgent neurosurgical or neuroradiological intervention. Whilst awaiting transfer to a neurological centre, active management of the patient must be instituted. This should include confirmation of the diagnosis with CT imaging, lumbar puncture or both, and recognition of the complications of subarachnoid haemorrhage, which include hydrocephalus, further haemorrhage and cerebral vasospasm. Medical management is directed towards maintaining adequate cerebral perfusion pressure whilst avoiding large increases in arterial blood pressure. Nimodipine therapy must be started early in an attempt to prevent cerebral vasospasm. The treatment options available at the neurological centre include surgical treatment or endovascular obliteration of the aneurysm or arteriovenous malformation.

Notes: Background Atopic Dermatitis (AD), hayfever and asthma are commonly summarized as atopic diseases. The spatial distribution of AD differs from that of asthma and hayfever, suggesting that AD might follow a different risk pattern than these diseases. AD can be differentiated into an allergic extrinsic form (EAD) and a non-allergic intrinsic form (IAD). Only EAD might follow the distribution and risk pattern that have been ascribed to asthma and hayfever.Objective To investigate the distribution and risk factor profile of AD and EAD focusing on environmental factors relating to the hygiene hypothesis.Methods Population-based cross-sectional study on 12 601 children aged 5–7 and 9–11 years from Dresden (Eastern Germany) and Munich (Western Germany). Information was obtained by International Study of Asthma and Allergic Childhood questionnaires, dermatological examinations and skin prick testing. AD-diagnosis ever, current AD-symptoms and visible eczema were investigated with their respective extrinsic forms.Results Maternal and paternal history of AD were equally strong determinants of the child's AD status. Factors related to the hygiene hypothesis like day-care attendance and number of older siblings were not associated with a decreased risk of AD. The proportion of EAD within AD was higher in Eastern than in Western Germany. The determinants of the diseases appeared to be similar for both EAD and IAD.Conclusions There was no evidence of the hygiene hypothesis holding true for AD or EAD. AD might be a separate entity than respiratory atopic diseases. Little is known about the risk factors of AD and factors different from those of respiratory allergic diseases should be considered in future research.

Notes: The effects of past applications of farmyard manure (FYM, applied from 1942 to 1967), metal-contaminated sewage sludge (applied from 1942 to 1961) and mineral fertilizer (NPK, applied from 1942 until now) on the microbial biomass and community structure in a sandy loam, arable soil from the Woburn Market Garden Experiment, UK, were investigated in 1998. Concentrations of Cu, Ni and Zn in soils which previously received sewage sludge were less than current European Union (EU) limits, but the soil Cd concentration was more than twice the permitted limit. Organic-C concentration in the FYM-treated soil and contaminated soils was about twice that of NPK-treated soil. The initial microbial biomass-C and estimates of total bacterial numbers by acridine orange direct count were significantly (P 〈 0.05) greater in the FYM-treated soil compared with the NPK-treated and the most contaminated soils. Total phospholipid fatty acid (PLFA) concentration (another measure of biomass) was significantly greater in the FYM-treated soil compared with either the low or high metal-contaminated soils, both of which contained similar PLFA concentrations. In the metal-contaminated soils, in contrast, fluorescent Pseudomonas counts, as a percentage of total plate counts, were at least 1.5 times greater than in the uncontaminated soils. The concentrations of these microbial parameters were significantly (P 〈 0.05) less in the NPK soil than in all the other treatments. Biomass-C as a percentage of organic-C was also significantly (P 〈 0.05) greater in the uncontaminated soils compared with the metal-contaminated soils. Biomass specific respiration rates in the metal-contaminated soils were c. 1.5 times those in the FYM-treated soil. In the metal-contaminated soils, the concentration of mono-unsaturated and hydroxy-fatty acids (derived from phospholipids), and lipopolysaccharide hydroxy-fatty acids (all indicative of Gram-negative bacteria) were significantly (P 〈 0.05) greater than branched fatty acids (indicative of Gram-positive bacteria). Furthermore, Gram-negative counts were 62–68% greater than Gram-positive counts in the metal-contaminated soils. Branched fatty acid concentration was significantly (P 〈 0.05) greater in the FYM-treated soil than in the metal-contaminated soils. Gram-positive counts were also 63% greater than Gram-negative counts in the FYM-treated soil. We found that effects of the relatively small heavy metal concentration caused measurable decreases in soil microbial biomass-C concentrations, acridine orange direct counts and Gram-positive counts. There were also increases in biomass specific respiration rates, and the microbial community had changed substantially, nearly 40 years after the metal inputs ceased. We conclude that, at the very least, the current EU permitted limits for heavy metals in agricultural soils should not be relaxed.