Microstructure, surface characterization and long-term stability of new quaternary Ti-Zr-Ta-Ag alloy for implant use.

The novel Ti-20Zr-5Ta-2Ag alloy was characterised concerning its microstructure, morphology, mechanical properties, its passive film composition and thickness, its long-term electrochemical stability, corrosion resistance, ion release rate in Ringer solution of acid, neutral and alkaline pH values and antibacterial activity. The new alloy has a crystalline α microstructure (by XRD). Long-term XPS and SEM analyses show the thickening of the passive film and the deposition of hydroxyapatite in neutral and alkaline Ringer solution. The values of the electrochemical parameters confirm the over time stability of the new alloy passive film. All corrosion parameters have very favourable values in time which attest a high resistance to corrosion. Impedance spectra evinced a bi-layered passive film formed by the barrier, insulating layer and the porous layer. The monitoring of the open circuit potentials indicated the stability of the protective layers and their thickening in time. The new alloy releases (by ICP-MS measurements) very low quantities of Ti, Zr, Ag ions and no Ta ions. The new alloy exhibits a low antibacterial activity.

Beta-amyloid: a disease target or a synaptic regulator affecting age-related neurotransmitter changes?

The amyloid cascade hypothesis sustains that beta-amyloid (Abeta) is the main pathogenetic factor of Alzheimer's Disease (AD). Although the direct and indirect neurotoxic role of Abeta are unchallenged, recent findings suggest that the peptide may have so far unforeseen physiological roles. In this regard, the observations showing the ability of Abeta to exert synaptic activities in absence of neurotoxicity are very intriguing. In particular, the peptide is able to affect synaptic transmission of different neurotransmitter systems in key brain areas that regulate executive and cognitive functions, an observation that points Abeta as a new neuromodulator. However, in a pathological context, Abeta may drive functional alterations of several neurotransmitter systems in the early phases of the disease, in turn producing subtle cognitive and behavioural disturbances in addition and before the well known neurodegenerative events. On the other hand, advancing age is the most significant risk factor for the development of AD. In fact, during aging increased Abeta levels have been reported. Moreover, several neurotransmitter systems undergo age-related changes in parallel to a decline of cognitive functions. However, the putative neuromodulatory role of Abeta in the context of aging is nowadays unknown. For these reasons, future studies about the spectrum of action of Abeta (brain areas and neurotransmitter systems affected) are particularly interesting since may suggest new therapeutic targets in order to sustain those functions which may be altered during aging.

Specific inhibitory effect of amyloid-beta on presynaptic muscarinic receptor subtypes modulating neurotransmitter release in the rat nucleus accumbens.

In this study we investigate on the effect of amyloid-beta1-40 (A beta 1-40) on the oxotremorine (OXO)-induced release of [(3)H] dopamine (DA), [(3)H]GABA and [(3)H]acetylcholine (ACh) from synaptosomes in the rat nucleus accumbens (NAc). OXO in presence of himbacine (HIMBA) was able to increase the basal release of [(3)H]GABA. The OXO-elicited [(3)H]GABA overflow was significantly antagonized by atropine (A; 94%), by the M3 antagonists DAU5884 (96%) and 4-DAMP (70%), and by A beta 1-40 (65%). Exposure of NAc synaptosomes to OXO produced a dose-dependent increase of [(3)H]DA overflow which was antagonized by A, partially inhibited by A beta 1-40 (100 nM) but unaffected by DAU5884 and 4-DAMP. The K(+)-evoked [(3)H]ACh overflow was inhibited by OXO. This effect was counteracted by the M2 antagonist AFDX-116 but not by the selective M4 antagonist mamba toxin 3 (MT3). The K(+)-evoked [(3)H]GABA overflow was also inhibited by OXO but conversely, this effect was counteracted by MT3 and not by AFDX-116. A beta 1-40 (100 nM) did not modify the inhibitory effect of OXO both on the K(+)-evoked [(3)H]ACh and [(3)H]GABA overflow. The results show that in the rat NAc, A beta 1-40 selectively inhibits the function of the muscarinic subtypes which stimulate neurotransmitter release and not those which modulate negatively the stimulated release.

Day hospital programmes for eating disorders: a review of the similarities, differences and goals.

Day hospital (DH) treatments for eating disorders (EDs) provide intensive daily care and allow patients to maintain and test their social relations and coping skills at home and outside. Although widespread, their description is lacking. This review compares the different types of DH described in the literature and presents our DH experience in Turin, Italy. We searched Psychinfo and Pubmed with the following keywords: anorexia nervosa, bulimia nervosa, EDs, DH, day treatment and partial hospitalisation. We found and reviewed the DH programmes of eleven specialised centres, which have some shared features but also many differences, suggesting that DH treatments are still largely experimental. Briefly, the shared elements are: biopsychosocial model as reference frame; cognitive-behavioural model or techniques; behavioural contract; patients' selection; body image therapy; involvement of family; weight normalisation/weight gain and modification/normalisation of eating behaviour as objectives. Nonetheless, shared opinions concerning inclusion criteria are lacking; the duration of DH treatment is surprisingly different among centres (from 3 to 39 weeks); the approach to eating and compensation behaviours ranges from control to autonomy; followup and psychometric assessment can be either performed or not; psychological and behavioural objectives can be different. This review suggests the existence of two different DH models: the first has a shorter duration and is mainly symptom-focused; the second is more individual-focused, has a longer duration and is focused on patients' relational skills, psychodynamic understanding of symptoms and more gradual changes in body weight. Further investigation is required to make DH treatment programmes measurable and comparable.

Selective impairment of noradrenergic transmission in the bisected rat vas deferens following photochemically-induced cerebral ischaemia.

BACKGROUND: Cerebrovascular disease may impair the autonomic control of peripheral organs including the male urogenital tract. This study investigates the effect of cortico-parietal focal ischaemia on the adrenergic and purinergic transmission in isolated epididymal and prostatic portion of rat vas deferens. METHODS: Focal brain ischaemia was induced in male rats by photochemical activation following rose bengal intravenous injection. Twenty-four hours following brain ischaemia, cumulative and non-cumulative concentration-response curves were obtained for noradrenaline and alpha,beta-methylene ATP in the right and left epididymal and prostatic portions of the vas deferens. Both portions were also stimulated by single-pulse or pulse trains at 2-30 Hz to produce isometric contractions. RESULTS: In both portions from ischaemic rats the response to exogenous noradrenaline was markedly depressed compared with controls. Acute cortico-parietal ischaemia almost completely abolished the adrenergic phase of the response to single-pulse stimulation in the epididymal portion of the vas deferens. In addition, brain ischaemia deeply depressed phasic and tonic contractions of the frequency-response curve in both portions of bisected vas deferens. CONCLUSIONS: Cortico-parietal ischaemia produces a selective noradrenergic impairment at the level of male sexual secondary organs that may contribute to sexual dysfunction after stroke.

The influence of alprazolam on the monoaminergic neurotransmitter systems in dysthymic patients. Relationship to clinical response.

The effects of alprazolam (1.5 mg/die) on the levels of the monoaminergic neurotransmitter metabolites, on the activity of the hypothalamic-pituitary-adrenal axis and on clinical outcome in subjects with primary late-onset dysthymia were investigated. Drug treatment significantly decreased plasma and urinary cortisol levels, serotonin platelet-bound and urinary 3-methoxy-4-hydroxyphenylglycol concentrations, while it increased plasma homovanillic acid (HVA) concentrations. Significant relationships were observed between neurochemicals and global scores or some items of the Hamilton Depression Rating Scale, before and after treatment. Patients responded positively (73%) to the therapy; clinical outcome was significantly correlated with plasma and urinary HVA levels. Collected data seem to support the hypothesis that central monoaminergic systems are in part involved in therapeutic response to alprazolam.

Aphid species--vectors of plum pox virus.

Plum pox virus (PPV) is widely spread by natural vectors present in plum orchards. The efficiency of transmission is dependent on the frequency of the occurrence of vectors and the cultivar susceptibility to this pathogen. Having in view that PPV has a wide range of annual and multiannual host plants and vectors, there is great concern for obtaining PPV-resistant cultivars. This report deals with the following vectors: Hyalopterus pruni, Brachycaudus cardui, Brachycaudus helichrysi. Myzus persicae and Phorodon humuli aphids, and Aculus fockeni mite. Seven different cultivars of Prunus domestica were utilized. To assess the virus transmission rate, 50-100 individual vectors per tree were used. The treatment of the trees was performed every four weeks and then the disease symptoms were observed. PPV was transmitted by all vectors studied, the rate ranging in dependence on the susceptibility of cultivars used. Thus, in cvs. Centenar, Pescarus, d'Agen, Stanley and Tuleu Gras, the transmission rate ranged from 20% to 60%, while in susceptible cvs. Vanat romanesc and Vanat de Italia--from 40% to 80%.

Catecholaminergic, neuroendocrine and anxiety responses to acute psychological stress in healthy subjects: influence of alprazolam administration.

We studied the effect of alprazolam (APZ) in 12 healthy volunteers on the psychological stress-induced activation of emotion and on the pituitary-adrenal, adrenomedullary and sympathoneuronal systems. After 3 days of placebo or APZ (1 mg/day orally) administration, we examined plasma levels of adrenocorticotropic hormone, cortisol, L-3,4 dihydroxyphenylalanine, dopamine, norepinephrine (NE), epinephrine, metanephrine, normetanephrine, homovanillic acid, vanillylmandelic acid, 3-methoxy-4-hydroxy phenyglycol, urinary levels of cortisol and catecholamines, circulatory responses and state anxiety levels in subjects undergoing psychological stress based on viewing horror, violence, danger and war film clips. Film viewing produced modest rises of state anxiety levels, of plasma NE concentration and of diastolic blood pressure in both the placebo and drug groups. APZ significantly reduced anxiety levels at the beginning of the experimental session and caused a decrease of noradrenergic and dopaminergic neurotransmitter and cortisol concentrations. Our data suggest that APZ reduced anxiety related to the expectation of the event, while the circuitry between structures responsible for anxiety and peripheral sympathoneural function was still found to be partly sensitive to film viewing.

Measurement of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in cultured rat mesencephalic neurons by high-performance liquid chromatography with electrochemical detection.

An HPLC method with electrochemical detection for the simultaneous measurement of serotonin (5-hydroxytryptamine) and 5-hydroxyindoleacetic acid in primary mesencephalic cell culture is described. The serotonin and 5-hydroxyindoleacetic acid cell content was measured on different days of growth in vitro; after twelve days in culture the amounts of serotonin and 5-hydroxyindoleacetic acid detected were 916.0 +/- 70.2 and 215.8 +/- 15.5 pg per well, respectively. The heterogeneity of neurons in our cultures and their capacity to take up serotonin were assessed by measuring the amounts of exogenous serotonin taken up in the presence of different monoamine uptake inhibitors. This method, sensitive and reliable, can represent a valid alternative to the use of labelled compounds.

Simultaneous measurement of total catecholamines and metanephrines in human urine by liquid chromatography with coulometric detection.

A simple routine method is described for simultaneous assay of total urinary norepinephrine, epinephrine, dopamine, normetanephrine and metanephrine. An internal standard of 3,4 dihydroxybenzylamine is added to the diluted urine and acidic hydrolysis of the conjugates is followed by reverse-phase HPLC separation and coulometric detection in the redox mode. The method is rapid and precise and it has a broad linear working range for all substances making it suitable for clinical analysis. Examples are shown of excretion patterns of catecholamines and metanephrines for healthy subjects and depressed patients.