Plasmapheresis treatment in Guillain-Barré syndrome: potential benefit over intravenous immunoglobulin.

Guillain-Barré syndrome includes acute inflammatory demyelinating polyradiculoneuropathy, acute motor axonal neuropathy, acute motor and sensory axonal neuropathy, Miller Fisher syndrome and acute pandysautonomia. Plasma exchange was the first treatment in Guillain-Barrd syndrome proven to be superior to supportive treatment alone and intravenous immunoglobulin was subsequently shown to be equally effective and is now commonly used as first-line treatment. We describe a 78-year-old woman who presented with a two-day history of progressive generalised weakness and left facial nerve palsy, preceded by a flu-like illness lasting for one week. A five-day course of daily immunoglobulin (0.4 g/kg/day) was commenced without benefit and progressive clinical deterioration. Seven days after completion of immunoglobulin treatment, plasma exchange was started with an exchange of about three litres of plasma every day for three days and every second day on two further occasions. A gradual improvement of respiratory function and peripheral muscle strength was observed after the first plasma exchange and on the eighth day the patient was weaned off mechanical ventilation. This case suggests that patients with severe Guillain-Barrd syndrome may benefit from plasma exchange after immunoglobulin treatment in refractory cases. Plasma exchange should be considered early in Guillain-Barrc syndrome cases with axonal involvement, and in the recurrent or familial Guillain-Barré syndrome forms.

'INDOTEST' in atypical hemicrania continua.

Hemicrania continua (HC) is an indomethacin-responsive headache characterized by a chronic, strictly unilateral, side-locked without side-shifting, persistent headache. We report three cases of HC with atypical features in which an acute administration of indomethacin 50 mg IM (INDOTEST) was performed. In all three cases INDOTEST predicted chronic responsiveness to indomethacin. Thus, in cases of HC with atypical features, INDOTEST could help for a correct diagnosis and therapy.

Brain perfusion effects of cholinesterase inhibitors in Parkinson's disease with dementia.

Several evidences suggest that cholinergic deficits may significantly contribute to dementia in Parkinson's disease (PDD) and acetylcholinesterase inhibitors (ChEIs) have been reported to improve cognitive symptoms in PDD, without worsening parkinsonism. Nineteen PDD patients underwent brain perfusion SPECT with (99m)Tc-ethyl cysteinate dimer after 6 months ChEIs treatment in order to evaluate the functional correlates of clinical improvement. A clear-cut cognitive improvement was reported in PDD patients with a significant improvement of ADAS-cog total score as well as of subscores exploring executive functions (p<0.01). MMSE total score did not significantly change after ChEIs but the subscore of attention significantly improved after therapy (p<0.01). No difference in motor performance as evaluated by UPDRS was reported. SPM analysis showed a significant increase of perfusion (p < 0.0001) in bilateral cingulate, and frontal regions after ChEIs. Our data confirm the efficacy of ChEIs in the treatment of dementia associated with PD mainly on attention and executive functions, and the functional findings indicate that this cognitive improvement could be associated with a sort of pharmacological frontal "re-afferentation".

Environmental factors and Parkinson's disease: a case-control study in the Tuscany region of Italy.

To date the aetiology of Parkinson's disease (PD) is unknown although both genetic susceptibility and environmental factors appear to play an important role in the development of the disease. Recent data have also indicated that chronic exposure to a common pesticide can reproduce the neurochemical, behavioral and neuropathological features of PD. The epidemiological studies previously carried on the prevalence of PD in population exposed to environmental factors have produced controversial results, probably because of different trial design and different analysis methods. A case-control retrospective study was conducted in a well-defined geographic area in Tuscany-Italy with the aim to identify environmental factors possibly related to PD. No significant difference between PD patients and control subjects was observed in time spent in rural or industrial residence, in well water drinking and in the exposure to herbicides and pesticides. A significant difference between patients with PD and controls was reported for cigarette smoking, controls resulting more likely cigarette smokers in comparison with PD patients. The present findings support the view of a protective effect of cigarette smoking and do not show any significant association between environmental factors and the risk of development of PD.

Presynaptic nigro-striatal function in a group of Alzheimer's disease patients with parkinsonism: evidence from a dopamine transporter imaging study.

The occurrence of parkinsonism in Alzheimer's disease (AD) is quite common, however the molecular and neurochemical changes underlying such extrapyramidal features in AD have been not fully understood. Post-mortem as well as in vivo imaging study have produced conflicting results as regards the existence of dopaminergic changes in AD. Aim of the present study was to investigate in vivo the nigro-striatal dopaminergic function in a group of AD patients with parkinsonism. Thirteen patients with AD and extrapyramidal features not related to past neuroleptic use (AD-P) underwent SPECT with 123I-FP-CIT, a ligand of dopamine transporter, and the data were compared with those obtained in 15 patients with Diffuse Lewy Body Dementia (DLBD), 20 patients with Parkinson's disease (PD), and 8 healthy elderly controls. The analysis of the data was performed by regions-of-interest approach and calculations of the striatal-to-non specific (occipital lobes) radioactivity ratios were made. The 123I-FP-CIT striatal uptake in patients with AD-P was similar to that obtained in the control population. Both the DLBD and PD groups showed significantly lower 123I-FP-CIT uptake in all striatal areas with respect to AD-P and control groups (p < 0.005). The lack of dopamine transporter changes in our series of AD-P patients can indicate that dopaminergic presynaptic function is preserved in this population and that different dopaminergic changes such as postsynaptic ones, or different neurotransmitter alterations might underlie the extrapyramidal features in AD.

Psychiatric comorbidity in a population of Parkinson's disease patients.

Behavioural disturbances are frequently observed in Parkinson's disease (PD), including mood and anxiety disorders. The existence of a comorbidity between such psychiatric disorders in PD patients has been suggested only in a few studies. To assess the prevalence of mood and anxiety disturbances, and the rate of comorbidity of such disorders in PD. Secondary aim was to correlate the prevalence of psychiatric disorders in PD with age, sex, laterality of motor symptomatology, clinical features, severity of disease, age of onset and PD duration, and anti-parkinsonian therapy. Ninety consecutive PD outpatients, and 90 age- and sex-matched controls were included. All PD patients enrolled were non-fluctuating (21 de novo, 69 treated with levodopa or dopamine agonists). PD patients and controls with Mini Mental State Examination score <23 were excluded. Psychiatric diagnosis was performed by semistructured interview according with DSM-IV criteria and the severity of depressive and anxious symptoms was rated with clinical rating scales. Major depression was found in 21.1% PD patients vs. 3.3% controls (P < 0.01, chi-square analysis), dystimia in 18.8% PD patients vs. 4.4% controls (P < 0.05), panic disorders in 30% PD patients vs. 5.5% controls (P < 0.01). No difference in the prevalence of other anxiety disorders was observed between the two groups. The comorbidity of mood and anxiety disorders was found in 19.3% PD patients vs. 8.6% controls (P < 0.01). No correlation was reported between the prevalence of behavioural disturbances and any of the demographic, clinical or pharmacological data taken into account. Our findings might suggest the existence of a wide spectrum of psychiatric disorders in PD ranging from pure depressive disorders, comorbid depressive and anxiety disorders, and pure anxiety disorders, presumably linked to the same neurobiological substrate.

Dopaminergic degeneration and perfusional impairment in Lewy body dementia and Alzheimer's disease.

The clinical differentiation of Lewy body dementia (LBD) from Alzheimer's disease (AD) may be difficult. The aim of the present study was to assess the dopamine transporter function and the perfusional pattern in LBD and AD in vivo. Twenty patients with probable LBD and 24 with probable AD underwent on 2 separate days a brain perfusional SPECT with 99mTc-ECD and a SPECT with (123)I-FP-CIT, a ligand of dopamine transporter. In LBD a significantly ( p<0.0005) lower ratio of specific (bilateral caudate nucleus, putamen) to non-specific (occipital cortex) (123)I-FP-CIT binding than in AD was reported. Perfusional data (SPM analysis) showed a significant ( p<0.001) decrease of temporo-parietal blood flow in AD versus LBD, whereas in LBD a significant ( p<0.001) occipital hypoperfusion with respect to AD was reported. Our findings confirm that dopaminergic nigrostriatal function is impaired in LBD. The selective occipital hypoperfusion in LBD needs to be further investigated.

Cellular events involved in survival of individual arbuscular mycorrhizal symbionts growing in the absence of the host

A survival strategy operating in the absence of the host was shown in obligately biotrophic arbuscular mycorrhizal (AM) symbionts. When no host-derived signals from the surrounding environment were perceived by germinating spores, fungal hyphae underwent a programmed growth arrest and resource reallocation, allowing long-term maintenance of viability and host infection capability. The early stages of mycelial growth of AM fungi were studied by a combination of time-lapse and video-enhanced light microscopy, image analysis, and immunodetection, with the aim of acquiring knowledge of cell events leading to the arrest of mycelial growth. The time-course of growth arrest was resolved by precisely timing the growth rate and magnitude of the mycelium originating from individual spores of Glomus caledonium. Extensive mycelial growth was observed during the first 15 days; thereafter, fungal hyphae showed retraction of protoplasm from the tips, with formation of retraction septa separating viable from empty hyphal segments. This active process involved migration of nuclei and cellular organelles and appeared to be functional in the ability of the fungus to survive in the absence of a host. Immunodetection of cytoskeletal proteins, metabolic activity, and the retention of infectivity of germinated spores confirmed the developmental data. The highest amounts of tubulins were detected when hyphal growth had ceased but when retraction of protoplasm was most active. This was consistent with the role of the cytoskeleton during protoplasm retraction. Succinate dehydrogenase activity in hyphae proximal to the mother spore was still detectable in 6-month-old mycelium, which remained viable and able to form appressoria and produce symbiotic structures.

Differential hyphal morphogenesis in arbuscular mycorrhizal fungi during pre-infection stages.

Roots of host plants elicit a local change in morphology in the hyphae of arbuscular mycorrhizal fungi, prior to the formation of appressoria. The elicited hyphae switch from their original branching pattern and apical dominance to differentiate in a new irregular, septate branching pattern with reduced inter-hyphal spacing. The extensive hyphal development associated with roots of host plants was shown to be due to the differential growth pattern described, and to precede the further cascade of events leading to appressorium formation and the development of a functional symbiosis.