Neurological manifestations of COVID-19 in patients: from path physiology to therapy

Coronavirus is a family of ARN positive single-stranded belonging to the family of Coronaviridae. There are several families of coronavirus that transmit more or less serious diseases. However, the so-called coronavirus-19 (SARS-CoV2) is the one that is currently causing most of the problems; in fact, biological dysfunctions that this virus causes provoke damage in various organs, from the lung to the heart, the kidney, the circulatory system, and even the brain. The neurological manifestations caused by viral infection, as well as the hypercoagulopathy and systemic inflammation, have been reported in several studies. In this review, we update the neurological mechanisms by which coronavirus-19 causes neurological manifestation in patients such as encephalomyelitis, Guillain-Barré syndrome, lacunars infarcts, neuropsychiatry disorders such as anxiety and depression, and vascular alterations. This review explains (a) the possible pathways by which coronavirus-19 can induce the different neurological manifestations, (b) the strategies used by the virus to cross the barrier system, (c) how the immune system responds to the infection, and (d) the treatment than can be administered to the COVID-19 patients.

Searching for a predictive peripherical biological model in parasuicidal behaviour

The aim of this study was to identify possible peripheral biological markers (both lipidic and hormonal) which can be easily used for the early detection of parasuicidal behaviour and to propose a predictive biological model of such behaviour. A case-control analytical study was undertaken at least 3 months after attempted suicide. Study was made of 128 patients who presented at the University General Hospital of Oviedo (Spain) with signs of self-intoxication. Lipidic and hormonal profiles were measured under basal conditions and comparison was made with a control group of healthy volunteer donors obtained from the Oviedo General Hospital blood bank. A discriminant analysis was later made with the aim of establishing a predictive biological model. This included the following variables: cholesterol, HDL-C, LDL-C and cortisol. Sensitivity and specificity were 62.5% and 65.6%, respectively. Replication and improvement of this model, through other prospective studies, could lead to the use of serum cholesterol and cortisol levels as inexpensive and readily available markers of suicide risk.

Response of Caligus rogercresseyi (Boxshall & Bravo, 2000) to treatment with Hydrogen Peroxide: Recovery of parasites, fish infestation and egg viability under experimental conditions

Hydrogen peroxide (HP) is used to remove C. rogercresseyi from fish but little is known about its effect on this species. This study determined EC₅₀ and concentration immobilizing 100% of specimens, capacity of parasites exposed to HP to recover and infest fish, and effect on survival into the copepodid stage. EC₅₀ and concentration immobilizing 100% of specimens were estimated by exposing parasites for 20 min to 11 concentrations and evaluating effect at 1 and 24 h post-exposure. Capacity to recover and infest fish, and survival into copepodid were evaluated by exposing parasites and eggs to HP for 20 min. Recovery and fish infestation were evaluated at 25 and 24 h post-exposure, respectively. Eggs were grown until control reached the copepodid stage and survival calculated. EC₅₀ was 709.8 ppm.100% immobilization was obtained at 825 ppm. Male and female recover 0.5 and 1 h post-exposure, respectively. Percentage of parasites exposed and not exposed to HP that were recovered on fish was not significantly different. Survival to copepodid was lower in those exposed to HP. HP effect is greater on copepodids, but 100% of the mobile stages are immobilized under 825 ppm causing detachment from fish and potentially driven away, reducing infestation risk.

Glutamate triggers neurosecretion and apoptosis in bovine chromaffin cells through a mechanism involving NO production by neuronal NO synthase activation

Previous work from our group stated that nitric oxide (NO), via cytokines, induces apoptosis in chromaffin cells by a mechanism involving iNOS, nNOS, and NF-κB. In this paper the involvement of glutamate as a possible intracellular trigger of neurosecretion and NO-mediated apoptosis has been evaluated. We show that chromaffin cells express different ionotropic and metabotropic glutamate receptors, this exerting different effects on the regulation of basal and glutamate-induced catecholamine secretion, via NO/cGMP. In addition, we studied the effects of endogenously generated NO, both basal and glutamate-stimulated, on apoptosis of chromaffin cells. Our results show that glutamate agonists are able to induce cell death and apoptosis in bovine chromaffin cells, parallel to an increase in NO production. Such effects were reversed by NOS inhibitors and glutamate receptor antagonists. Under basal conditions, iNOS inhibitors did not have any effect on apoptosis, whereas nNOS inhibitors induced apoptosis, indicating a neuroprotective effect of constitutive nNOS-generated NO. In contrast, glutamate-induced apoptosis was strongly reversed by nNOS inhibitors and weakly by iNOS inhibitors, thus indicating nNOS involvement in glutamate-mediated apoptosis. These results were confirmed by the fact that nNOS expression, but not iNOS, is specifically activated by glutamate. Finally, our results suggest the participation of PKG, PKA, PKC, and MAPK pathways in glutamate-mediated nNOS activation in chromaffin cells and point out the involvement of both PKA and PKC signaling pathways in the apoptotic effect of glutamate.

[Recommendations for the management of influenza in pediatrics (2009-2010).]

Specific action plans from various institutions, governments and scientific societies have been identified and implemented to combat the A H1N1 2009 influenza virus pandemic. This document sets out the recommendations of the Spanish Association of Pediatrics for the management of influenza in children for influenza season 2009-2010. The risk factors for influenza A H1N1 2009 in pediatric patients, the clinical course, severity and complications are similar to seasonal influenza. In most cases, the diagnosis of influenza will be based on clinical suspicion, without viral subtype differentiation. In a patient with influenza virus infection, the criteria for referral and hospital admission will be based broadly on the signs of clinical severity or complications, regardless of the causative virus. Children with influenza but with no signs of clinical severity or complications do not require antiviral treatment. Physical measures of hygiene and isolation are essential to reduce the transmissibility of the disease. The influenza vaccines in infancy, for both seasonal influenza and for influenza A H1N1 2009, should be directed primarily at patients with risk factors.

Computational modeling tools for the design of potent antimalarial bisbenzamidines: Overcoming the antimalarial potential of pentamidine

Malaria is nowadays a worldwide and serious problem with a significant social, economic, and human cost, mainly in developing countries. In addition, the emergence and spread of resistance to existing antimalarial therapies deteriorate the global malaria situation, and lead thus to an urgent need toward the design and discovery of new antimalarial drugs. In this work, a QSAR predictive model based on GETAWAY descriptors was developed which is able to explain with, only three variables, more than 77% of the variance in antimalarial potency and displays a good internal predictive ability (of 73.3% and 72.9% from leave-one-out cross-validation and bootstrapping analyses, respectively). The performance of the proposed model was judged against other five methodologies providing evidence of the superiority of GETAWAY descriptors in predicting the antimalarial potency of the bisbenzamidine family. Moreover, a desirability analysis based on the final QSAR model showed that to be a useful way of selecting the predictive variable level necessary to obtain potent bisbenzamidines. From the proposed model it is also possible to infer that elevated high atomic masses/polarizabilities/van der Waals volumes could play a negative/positive/positive role in the molecular interactions responsible for the desired drug conformation, which is required for the optimal binding to the macromolecular target. The results obtained point out that our final QSAR model is statistically significant and robust as well as possessing a high predictive effectiveness. Thus, the model provides a feasible and practical tool for looking for new and potent antimalarial bisbenzamidines.

Folate status and S-adenosylmethionine/S-adenosylhomocysteine ratio in colorectal adenocarcinoma in humans

OBJECTIVES

This study reports the influence of colorectal neoplasia on methylation intermediates and folate concentrations in human colonic mucosa, as well as systemic measures of folate status, to examine biomarkers and possible mechanisms of folate-related carcinogenesis.

SUBJECTS

A total of 47 patients were selected from those previously diagnosed with adenocarcinoma of the colorectum undergoing surgery. For each individual, we obtained a biopsy of the adenocarcinoma and a biopsy of normal appearing mucosa, to perform an intra-individual comparison.

RESULTS

The 'methylation' ratio (S-adenosylmethionine/S-adenosylhomocysteine (SAH)) was lower in pathological tissue vs normal mucosa (P=0.08), mainly due to a much higher SAH concentration (P<0.005). Colonic folate concentration was significantly diminished in malignant tissue (P<0.0001). Plasma homocysteine concentration was within the normal to high range, and folate and vitamin B12 plasma concentrations were within the low to normal range as compared with normative values.

CONCLUSION

Our results contribute to the hypothesis that altered DNA methylation and methyl metabolism is associated with colorectal neoplasia.

Mitochondrial involvement in nitric oxide-induced cellular death in cortical neurons in culture

Nitric oxide (NO) is an unstable molecule with physiological and pathological properties. In brain, NO acts as a modulator of neurotransmission as well as a protector against neuronal death from several death stimuli. However, beside this protector effect, high NO concentrations produce neuronal death by a mechanism in which the caspase pathway is implicated. In this work, we demonstrate that in cortical neurons the NO toxicity is mediated by mitochondrial dysfunction. SNAP, an NO donor, induces apoptosis in these cells because it 1) increases the p53 and 2) induces cytochrome c release and activation of caspase-9 and caspase-3. SNAP also induces necrosis, through 1) breakdown of the mitochondrial membrane potential, 2) ATP decrease, 3) ROS formation, and 4) LDH and ATP release, indicative of oxidative stress and death by necrosis. To sum up, in cortical neurons, high NO concentrations produced cellular death by both an apoptotic and a necrotic mechanism in which the mitochondria are implicated.

Cadmium induces reactive oxygen species generation and lipid peroxidation in cortical neurons in culture

Cadmium is a toxic agent that it is also an environmental contaminant. Cadmium exposure may be implicated in some humans disorders related to hyperactivity and increased aggressiveness. This study presents data indicating that cadmium induces cellular death in cortical neurons in culture. This death could be mediated by an apoptotic and a necrotic mechanism. The apoptotic death may be mediated by oxidative stress with reactive oxygen species (ROS) formation which could be induced by mitochondrial membrane dysfunction since this cation produces: (a) depletion of mitochondrial membrane potential and (b) diminution of ATP levels with ATP release. Necrotic death could be mediated by lipid peroxidation induced by cadmium through an indirect mechanism (ROS formation). On the other hand, 40% of the cells survive cadmium action. This survival seems to be mediated by the ability of these cells to activate antioxidant defense systems, since cadmium reduced the intracellular glutathione levels and induced catalase and SOD activation in these cells.

Preliminary tests on nisin and pediocin production using waste protein sources. Factorial and kinetic studies

Lactic acid bacteria, the object of current interest as bacteriocin producers, are microorganisms with complex requirements for peptidic sources, making them appropriate indicators for testing the suitability of formulations based on proteinaceous wastes for use as microbiological media. Different peptones obtained from visceral and fish muscle residues promoted growth of lactic acid bacteria when applied individually or in combination. Kinetic parameters and bacteriocin production were similar and, in some cases (pediocin), far superior (>500%) to those obtained with bactopeptones and commercial media specifically recommended for lactic acid bacteria growth. Visceral residues, especially when subjected to a brief process of autohydrolysis at 20 degrees C, were more efficient for bacterial growth than muscle, even when muscle was treated with pepsin.

Proteases production by two Vibrio species on residuals marine media

A comparative study was carried out on the growth and production of alkaline proteases by two Vibrio species using different marine peptones from fish viscera residues. The bacteria tested, Vibrio anguillarum and Vibrio splendidus, are producers of high levels of proteolytic enzymes which act as factors of virulence in fish cultures, causing high mortality rates. The kinetic assays and subsequent comparison with the parameters obtained from the adjustment to various mathematical models, highlighted the potential interest of the media formulated, for their possible production on an industrial scale, particularly the production of proteases by V. anguillarum growing in rainbow trout and squid peptones.

Nitric oxide and peroxynitrite induce cellular death in bovine chromaffin cells: Evidence for a mixed necrotic and apoptotic mechanism with caspases activation

Treatment of chromaffin cells with nitric oxide (NO) donors (SNP and SNAP) and peroxynitrite produces a time- and dose-dependent necrotic and apoptotic cell death. Necrotic cell death was characterized by both an increase in lactate dehydrogenase and ATP release and changes in nuclei and cell morphology (as seen with fluorescence microscopy analysis with propidium iodide and Hoechst 33342). Apoptotic cell death was characterized by nuclear fragmentation and presence of apoptotic cell bodies, by a decrease in DNA content, and by an increase in DNA fragmentation. Treatment of chromaffin cells with lipopolysaccharide (LPS) or cytokines (interferon-gamma, tumor necrosis factor-alpha) resulted only in apoptotic cell death. Apoptotic effects of NO-inducing compounds were specifically reversed, depending on the stimuli, by the NO scavenger carboxy-PTIO (CPTio) or by the NOS inhibitors L-NMA and thiocitrulline. NO-induced apoptotic death in chromaffin cells was concomitant to a cell cycle arrest in G0G1 phase and a decrease in the number of chromaffin cells in the G2M and S phases of cell cycle. All NO-producing compounds were able to induce activation of caspase 3 and cytochrome c release, and specific inhibitors of caspase 3 and 9, such as Ac-DEVD-CHO (CPP32) and Ac-Z-LEHD-FMK, respectively, prevented NO-induced apoptosis in chromaffin cells. These results suggest that chromaffin cells could be good models for investigating the molecular basis of degeneration in diseases showing death of catecholaminergic neurons, phenomenon in which NO plays an important role.

GETAWAY descriptors to predicting A2A adenosine receptors agonists

The GEometry, Topology and Atom-Weights AssemblY approach has been applied to the study of the A(2A) adenosine receptors agonist effect of 29 adenosine analogues: N(6)-arylcarbamoyl, 2-arylalkynyl-N(6)-arylcarbamoyl, and N(6)-carboxamido derivatives. A model able to describe more than 77% of the variance in the experimental activity was developed with the use of the mentioned approach. In contrast, no one of four different approaches, including the use of Topological, Galvez Topological Charges indexes, Geometrical and WHIM descriptors were able to explain more than 70% of the variance in the mentioned property with the same number of variables in the equation.

SNAP, a NO donor, induces cortical neuron death by a mechanism in which the caspase pathway is implicated

In this paper, we present data which demonstrate that, in cortical neurons, SNAP induces loss in cell viability as evaluated by the XTT test. This cell death started at 250 microM SNAP when the treatment was performed in a serum-free medium and at 10 microM when the treatment was given in the presence of serum. This death was mediated, at least in part, by an apoptotic mechanism detected by flow cytometry and DNA fractionation. The highest SNAP concentrations induced a dual behavior on caspase-3 activity. Concentrations of 250 microM in the absence of serum and 10 microM to 300 microM in the presence of serum produced caspase-3 activation. This indicates that NO induces neuronal death by an apoptotic mechanism in which the caspase pathway is implicated. Higher SNAP concentrations (500 microM to 1 mM) diminished the caspase-3 activity to levels similar or even lower than control values. This profile was observed in the absence as well as in the presence of serum in the medium. The caspase-3 inhibition mediated by the highest SNAP concentrations did not imply NO cellular protection since the caspase-3 inhibition mediated by these SNAP concentrations neither correlated with cellular viability nor with cellular apoptosis. The possible mechanism of caspase-3 inhibition at the highest SNAP concentrations used is discussed.

Nitric oxide donors induce calcium-mobilisation from internal stores but do not stimulate catecholamine secretion by bovine chromaffin cells in resting conditions

The potential role of nitric oxide (NO) donors and peroxynitrites on both basal catecholamine (CA) secretion and modulation of calcium levels has been investigated in primary cultures of bovine chromaffin cells. NO donors did not modulate catecholamine secretion, while peroxynitrites induced a time dose-dependent increase in basal CA secretion. Two facts may explain the lack of these compounds on basal CA secretion. NO donors induce, on the one hand, an increase in intracellular calcium levels by depletion of internal IP3-stores from endoplasmic reticulum. On the other hand, a small calcium influx through N-type voltage-dependent calcium channels (VDCC), which seem not to be coupled to exocytosis of adrenaline and noradrenaline in chromaffin cells. Both effects, calcium-mobilisation from internal stores and calcium entry through N-type VDCC are mediated by cGMP synthesis. In contrast, peroxynitrites induce an increase in basal CA secretion by both a decrease of intracellular catecholamine content and a toxic effect on cellular membrane. All these results, taken together, could explain contradictory results in the literature on the role of NO on basal catecholamine secretion and on modulation of intracellular calcium in chromaffin cells.

Stimulation of Bacteriocin Production by Dialyzed Culture Media from Different Lactic Acid Bacteria

The cross-effects of dialyzed postincubates (with a cut-off at 1000 Da) on the biomass and bacteriocin production of six strains of lactic acid bacteria were studied, and a predominance of stimulating responses was found, the characteristics of which suggested merely nutritional effects or the presence of precursor fragments of the bacteriocins. Additionally, cluster analysis of the detected responses provides an approach to define groups of highly compatible (potential consortia) or doubtfully compatible strains of lactic acid bacteria. Such a definition, which does not claim taxonomic value, has practical interest, however, in cases (e.g., silage production) in which it is convenient to use mixed inocula including strains able to establish positive interactions.

SNAP, a NO donor, induces cellular protection only when cortical neurons are submitted to some aggression process

Nitric oxide is a versatile molecule, which plays important physiological and pathological roles. Its protective and toxic actions have been already evidenced in several cell types. However, the protective effect in cortical neurons remains elusive. In this work, we demonstrate that the NO-donor SNAP may induce both neuroprotection and neurotoxicity in this sort of cells. The protective effect of NO was evidenced when cortical neurons were exposed to deleterious conditions, such as serum deprivation. Serum deprivation induces apoptotic cortical neuron death through a caspase-dependent mechanism. Under these conditions, SNAP was able to oppose cell death through both caspase-3 inhibition and/or increase of antiapoptotic protein levels (Bcl-2 and Bcl-x(L)). On the other hand, in a normally serum-supplemented medium, high dose of SNAP behaves as a neurotoxic agent, through a mechanism which involves caspase-3 activation.

Effects of Aeration on Growth and on Production of Bacteriocins and Other Metabolites in Cultures of Eight Strains of Lactic Acid Bacteria

In general, it is accepted that the production of bacteriocins in lactic acid bacteria cultures implies moderately to highly restrictive conditions regarding the availability of oxygen. However, the situation appears to be more complex, probably owing to the facultative anaerobic character of these microorganisms. By studying the culture of eight strains of lactic acid bacteria carried out in vessels with different loads of medium within an interval that determines linearly the minimum availability of oxygen, the existence of three types of behavior was highlighted: production increases (1) with the availability of oxygen, (2) with the restriction of this availability, and (3) toward both extremes of these conditions, diminishing in intermediate situations. These behaviors affected not only the production of bacteriocins, but also their metabolic character (in the Luedeking and Piret sense), as well as the production of other characteristic metabolites, such as lactic acid, acetic acid, and ethanol.

Peptones from autohydrolysed fish viscera for nisin and pediocin production

Various peptones obtained from hydrolysed visceral homogenates of four fishery residues showed their suitability for promoting the growth of lactic acid bacteria, micro-organisms with particularly complex requirements regarding peptidic nutrients. The assay of several treatments with two bacterial species, producers of the two main bacteriocins (nisin and pediocin) demostrated that optimum conditions only imply a brief autohydrolysis at natural pH and room temperature, with subsequent steam-flow stabilisation. Later kinetic analysis of the cultures of both bacteria in the best media provided parameters which, for production of both biomass and bacteriocins (the latter behaved in the majority of cases as a mixed metabolite), indicate comparable or superior results to those found in costly commercial media, specifically recommended for culture of lactic acid bacteria.

Therapeutic efficacy and safety of multiple intravenous infusions of infliximab in refractory ankylosing spondylitis patients with axial involvement

OBJECTIVE

To evaluate the clinical response and safety profile of infliximab in refractory ankylosing spondylitis patients.

METHODS

Patients with active ankylosing spondylitis, despite methotrexate therapy, were included in an open-label, single-centre study. Patients were given 3-5 mg/kg infliximab infusions at Weeks 0, 2, 6, and q8 etc up to Week 30, together with methotrexate at the dosage taken prior to study inclusion, and were followed-up for a 34-week period.

RESULTS

Nine patients with mean age 43 years and mean disease duration 7 years, diagnosed with pure axial ankylosing spondylitis were included. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), duration of morning stiffness, physician's global assessment of disease activity (PhGADA), visual analogue scale (VAS) pain, enthesis index, occiput-to-wall test, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and Bath Ankylosing Spondylitis Functional Index (BASFI) significantly improved by Week 6. No adverse events related with the drug were recorded during the 34-week follow-up period.

CONCLUSION

Efficacy results are similar to those previously published. No adverse events were seen during therapy, and antinuclear antibody profiles were negative. The association of methotrexate with infliximab can improve the safety profile.

Pediocin production by Pediococcus acidilactici in solid state culture on a waste medium: process simulation and experimental results

The production of pediocin by Pediococcus acidilactici was comparatively studied in submerged and solid-state culture, using polyurethane foam particles soaked in commercial (MRS) and waste media with various supplements, where product concentrations were 15 times higher in MRS medium. For the solid state analysis, cultures were treated by successive compression and refilling of tubular minireactors equipped with a piston, without the need for reinoculation. This method was found to be simple, reproducible, and easily controllable, allowing culture productivity to be maintained for long periods of time without alterations in the basic properties of the system. In addition, yields were found to be superior compared to those from submerged culture. The system kinetics were modeled on the basis of widely accepted assumptions with a good fit to the experimental results and observed biomass fluctuations less evident than those predicted by the kinetic model.

Substrate inhibition of Pediococcus acidilactici by glucose on a waste medium. Simulations and experimental results

AIMS

The possibility of substrate inhibition by glucose on biomass and pediocin production was studied in cultures of Pediococcus acidilactici on a residual medium.

METHODS AND RESULTS

Calculation of the substrate inhibition coefficient in the context of microbial growth is generally laborious, and very prone to experimental error. However, a simulation combining logistic and Monod kinetics equations demonstrates that quantitative evidence for this type of inhibition, without the possibility of misinterpretation, can be obtained through the comparison of punctual preasymptotic productions as a function of substrate concentration.

SIGNIFICANCE AND IMPACT OF THE STUDY

It was concluded that glucose had an inhibitory effect on growth, but not on bacteriocin production.

Survival of Lactic Acid Bacteria in Seawater: A Factorial Study

A feasibility study of lactic bacteria as potential probiotics in larval cultures of marine fish was performed by investigating the survival of five strains of lactic bacteria in seawater by readily standardized procedures at different temperatures and salinities. These conditions were chosen in such a way that their combinations define a complete first-order factorial design. Depending on the strain and the ambient conditions, the survival adhered to first-order kinetics in some cases, and to the Gompertz equation in others. The half lives (t0.5) calculated from these models were subsequently introduced as responses to the factorial designs, estimating the coefficients of empirical equations that describe the group effect of temperature and salinity on t0.5. Simply additive effects were found in two cases, a negative first-order interaction in another case, while another two required second-order models.

Expression and functional properties of group I metabotropic glutamate receptors in bovine chromaffin cells

We demonstrate the presence and functional properties of Group I metabotropic glutamate receptors (mGluRs) expressed in chromaffin cells. Immunocytochemical techniques revealed that two mGluR subtypes (mGluR1alpha and mGluR5) are expressed in chromaffin cells, located in both the cytoplasmic membrane and the cytosol surrounding the nucleus. These mGluRs are functionally active on catecholamine (CA) secretion in chromaffin cells because both (1S, 3R)-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) and the specific agonist of Group I mGluRs, (S)-3,5-dihydroxyphenylglycine (DHPG), were able to stimulate the release of CAs (adrenaline and noradrenaline) in a dose-response manner. These effects were specifically reversed by L-(+)-2-amino-3-phosphonopropionic acid (L-AP3), a selective antagonist of the Group I metabotropic glutamate receptors. t-ACPD induced an increase in CA secretion in both the presence and absence of extracellular calcium, the former effect being accompanied by cell membrane depolarization. Noradrenaline (NA) release was higher in the presence of extracellular calcium than in its absence, whereas adrenaline release was of the same order under both conditions. These results indicate that different subtypes of Group I mGluRs are present in noradrenergic and adrenergic cells. Fluorescence imaging techniques in single cells showed different t-ACPD-induced increases in intracellular calcium in different chromaffin cells: in chromaffin cells, 67% expressed functional metabotropic glutamate receptors and with nicotinic receptors, whereas the remaining 33% expressed only nicotinic receptors. In the absence of external calcium, only about 25% of cells responded to t-ACPD-increased intracellular calcium by increasing inositol 1,4,5-trisphosphate (IP(3)) concentration and subsequent calcium mobilization from intracellular stores, whereas the remaining 75% increased intracellular calcium by promoting Ca(2+) influx from the extracellular medium through L- and N- but not P/Q voltage-dependent calcium channels.

Molecular mechanisms of glutamate release by bovine chromaffin cells in primary culture

Previous work indicated that glutamate could be involved in the regulation of catecholamine secretion in bovine chromaffin cells. Thus, the question arises on the source of this putative regulatory glutamate. In this work we have examined the possibility that glutamate could be released from chromaffin cells. Data from this study indicate that chromaffin cells are able to release glutamate when they are stimulated by different depolarising agents such as 60 mM KCl, 1 mM 4-aminopyridine or 50 microM veratridine. The amount of glutamate released by these compounds was 0.32 nmol/10(6) cells (9.24% of cellular glutamate content), 0.275 (7.86%) and 0.158 (4.52%) for KCl, 4-AP and veratridine stimulation, respectively. All these catecholamine-secretagogues induced glutamate secretion by two mechanisms: 1) a Ca(2+)-dependent, probably exocytotic, mechanism and 2) a Ca(2+)-independent mechanism mediated by reversion of the electrogenic glutamate transporter. Analysis of Ca(2+)-dependent and independent releases for different compounds carried out by several experimental approaches, indicate that Ca(2+)-dependent release was the predominant mechanism for release induced by 4-aminopyridine (84% of total release) and high KCl (63%) whilst Ca(2+)-independent release was predominant for veratridine (67%). The Ca(2+)-dependent glutamate release evoked by depolarisation of chromaffin cells with high KCl and 4-AP could be split into both a fast and a slow kinetic component, which might correspond to the release of docked and mobilised chromaffin granules, respectively. On the other hand, depolarisation of cells with veratridine result in glutamate release with only the fast kinetic component. In the case of 60 mM KCl-evoked glutamate release, the fast component exhibited a decay time of <1 s and accounted for 0.63 nmol glu/6x10(6) cells (70% of total exocytotic release), whereas the slow component, which exhibited a decay time of 231 s, accounted for the release of 0.27 nmol glu/6x10(6) cells (30% of total exocytotic release). By contrast in the case of 4-aminopyridine the fast component of exocytosis only represents a 19% of total secretion and the slow a 81% with a decay time of 94 s. These data are very similar to those found in neurones and support the possible intracellular origin of glutamate having a role in the regulation of catecholamine secretion from chromaffin cells. In support of this, we have found that glutamate secretion could be evoked by stimulation of the nicotinic cholinergic receptors.

Apoptosis and necrosis: two distinct events induced by cadmium in cortical neurons in culture

(1) Cadmium is an extremely toxic metal commonly found in industrial workplaces, a food contaminant and a major component of cigarette smoke. Cadmium can severely damage several organs, including the brain. In this work, we have studied both the cadmium toxicity on rat cortical neurons in culture and the possible protective effect of serum. (2) Our results indicate that: (1) cadmium is taken up by the neurons in a dose and serum dependent way; (2) cadmium, at concentrations from 1 micro M or 10 micro M (depending on the absence or the presence of serum) up to 100 micro M, decreases the metabolic capacity, which was evaluated by the XTT (tetrazolium salt) test; (3) cadmium induces apoptosis and LDH (lactate dehydrogenase) release in a dose dependent way; (4) in a serum-free medium, the cadmium-induced apoptosis is accompanied by caspase-3 activation; (5) both the caspase-3 activation and the cadmium-induced apoptosis are reversed by N-acethyl-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-CHO), a selective caspase-3 inhibitor, indicating that the caspase-3 pathway is involved in cadmium-induced apoptosis in cortical neurons; and (6) the cadmium concentrations which produce caspase-3 activation do not modify the intracellular ATP levels; however, higher cadmium concentrations lead to both intracellular ATP depletion and ATP release, but do not increase the caspase-3 activity, indicating that cadmium also produces cellular death by necrosis. (3) These results suggest that cadmium induces either apoptosis or necrosis in rat cortical neurons, depending on the cadmium concentration.

Neuronal nitric oxide synthase modulates basal catecholamine secretion in bovine chromaffin cells

The role of endogenously produced nitric oxide (NO) in the regulation of basal catecholamine (CA) secretion was studied in chromaffin cells. Treatment of chromaffin cells with nitric oxide synthase (NOS) inhibitors produced a dose-dependent increase in basal catecholamine secretion, which paralleled their ability to inhibit NOS activity. This inhibitory profile was similar to that found in neurons, suggesting the constitutive expression of neuronal NOS (nNOS) in these cells, which was confirmed by Western blot analysis. A study of the kinetics and pharmacology of nNOS activity expressed in chromaffin cells in culture indicated that NOS activity is calcium-dependent, increases with time, and is highly dependent on both intracellular concentrations of L-arginine (K(m) approximately 4 microM, V(max) = 908 +/- 60 pmol/hr x 10(6) cells) and transport of L-arginine into the cells (exhibiting two affinity constants of k(1) = 3.2 +/- 0.3 microM and k(2) = 126 +/- 5.5 microM). The effects of NOS inhibitors on CA secretion were mediated by the L-arginine-NO-cGMP pathway, insofar as exogenous L-arginine was able to partially block the increase in CA secretion evoked by them, and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ), a specific inhibitor of guanylate cyclase, and zaprinast, an inhibitor of the cGMP phosphodiesterase, were able to increase and inhibit, respectively, basal CA secretion in a dose-dependent manner. These results suggest that chromaffin cells exhibit a tonic production of NO by nNOS that keeps the basal CA secretion at low levels, and this could be necessary for maintaining a normotensive state.

Use of MDMA and other illicit drugs by young adult males in northern Spain. A five-year study

AIM

To measure the prevalence of 3,4-methylenedioxymethamphetamine (MDMA) and other drug use in young males entering compulsory military service in Asturias (northern Spain) and to define trends in MDMA use in this group during the period from 1995 to 1999. We also sought to determine whether MDMA users have distinct personality features or higher levels of sensation seeking.

METHODS

3,634 conscripts [mean age (SD) = 20.19 years (2.52)] who entered military service during the period between 1995 and 1999 were evaluated using the World Health Organization (WHO) questionnaire for drug consumption, the Eysenck Personality Questionnaire-A (EPQ-A), and the Zuckerman Sensation Seeking Scale.

RESULTS AND CONCLUSIONS

The prevalence of lifetime, previous year and previous month MDMA use among military recruits between 1995 and 1999 was 10.9, 7.8 and 4.5%, ranking fifth among illicit drugs ever used. Once individuals used MDMA for the first time, they were likely to use it again, with 71% of individuals who had ever used MDMA reporting that they had used it during the past year (ranking second only to hallucinogens), and 41% reporting having used it in the last month. Compared to recruits who had never used MDMA (but who may have used other illicit drugs), MDMA users had a more extensive drug abuse history. Recruits who had used MDMA during the year prior to study had significantly higher scores on the Neuroticism and Psychoticism Subscales of the EPQ-A, and reported higher levels of sensation seeking.

Evaluating changes in sexual functioning in depressed patients: sensitivity to change of the CSFQ

Accurately evaluating alterations in sexual functioning requires a validated instrument that measures clinically relevant change over time. One-hundred one depressed patients from 15 Spanish out-patient clinics completed the Changes in Sexual Functioning Questionnaire (CFSQ; Clayton, McGarvey, & Clavet, 1997) at baseline and after 6 months of treatment with fluoxetine, nefazodone, paroxetine, or venlafaxine. Sexual desire/interest showed a nearly substantial floor effect (30% of patients indicated the maximum score) for women in the nefazodone group at baseline and in the paroxetine group at final visit. The percentage of dimensions recording change was greater for women (80%) than for men (20%) in the nefazodone group (improving changes) and greater for men (40%) than for women (20%) in the paroxetine group (worsening changes). Highest effect sizes were found on sexual desire/frequency with improvement in women in the nefazodone group (SES = 0.49), and on orgasm/ejaculation with worsening in men in the paroxetine group (SES = -1.45). In conclusion, the CSFQ is sensitive to bidirectional changes and is appropriate for measuring sexual dysfunction.

Joint effect of nisin, CO2, and EDTA on the survival of Pseudomonas aeruginosa and Enterococcus faecium in a food model system

A study on the joint effect of either nisin or Nisaplin, headspace CO2 levels, and EDTA on the survival of Pseudomonas aeruginosa and Enterococcus faecium was carried out in a water-soluble fish muscle extract at 3 degrees C using a second-order rotatable factorial design. E. faecium was completely deactivated by all processing after 2 days of storage. In contrast, P. aeruginosa was much less susceptible to treatments, and cell death was satisfactorily described by two models. Nisin increased cell death, whereas Nisaplin (commercial form of nisin) was not suitable, as it caused undesirable interference, presumably due to its co-compounds. Interactions between Nisaplin or nisin and either EDTA or CO2 were found to be nonstatistically significant. Factors that could account for this unexpected lack of synergism are discussed. However, a statistically significant positive interaction was found between CO2 and EDTA. This finding could allow CO2 levels to be decreased and hence to reduce the main disadvantages of CO2 application, namely, exudation and acidification.

Calcium channel types involved in intrinsic amino acid neurotransmitters release evoked by depolarizing agents in cortical neurons

Although numerous biochemical and electrophysiological studies have already established many of the properties of the putative Ca2+ receptor for exocytosis at the synapse, the molecular mechanism that involves the influx of Ca2+ and the release of neurotransmitters has remained elusive. Several relationships have been established between neurotransmitter release and Ca2+ channel involved, but no work attempting to connect a particular neurotransmitter release, the effector which produces the release and the opening of a Ca2+ channel type has been performed. This work shows, data dealing with this subject. Based on our results, we have reached the following conclusions: (1) Ca2+ channel types P/Q, N and L mediate Ca2+ entry evoked by high KCl and veratridine, and P/Q and N but not L-type Ca2+ channels are involved when the effector is 4-aminopyridine (4-AP); (2) When we compare the relationship between the amino acid release and the Ca2+ channels which are opened by different depolarizing agents, we find that the release of a particular amino acid neurotransmitter not only depends on the opening of the voltage-dependent Ca2+ channel but also on the effector which produces the opening; and (3) the amount of amino acid release evoked by the different depolarizing agents is not correlated with the elevation of intracellular Ca2+ produced by them. From all of these results, we may conclude that calcium concentration in the active zone is not the only important factor in mediating amino acid release.

Quality of life and disability in patients with obsessive-compulsive disorder

The aim of this study is to describe the situation of Spanish obsessive-compulsive disorder (OCD) patients and compare it to that of the general population and other patient groups.

METHODS

Thirty-six OCD patients on maintenance treatment were evaluated using the Y-BOCS, SF-36, and DAS-S. Their SF-36 scores were compared to Spanish norms and to those obtained from U.S. OCD patients, schizophrenic outpatients, depressed outpatients, heroin dependents, patients on hemodialysis, and kidney transplant recipients.

RESULTS

Sixty-one percent of the patients had severe or extremely severe symptoms. Their quality of life was worse when compared with the Spanish norms in all SF-36 areas, but especially with respect to mental health. In contrast to U.S. OCD patients, social functioning is more impaired in the Spanish OCD patients. OCD patients reported the same quality of life as schizophrenics in the areas of mental health, but better in the areas of physical health. Compared with heroin dependents and depressed patients, their quality of life was worse. On mental health scales, OCD patients scored worse than somatic patients.

CONCLUSIONS

OCD in the Spanish population was shown to be associated with worse quality of life than for any other patient group (including physical groups), except schizophrenics.

Nicotinic receptors mediate the release of amino acid neurotransmitters in cultured cortical neurons

Nicotine stimulation of cortical neurons obtained from gestation day 19 rats provoked a dose-dependent release of aspartate, glutamate, glycine and GABA, indicating a functional role for the nicotinic receptor in this model. This release was exclusively Ca2+-dependent (vesicular release) in the case of aspartate and dual Ca2+-dependent and Ca2+-independent) for glutamate, glycine and GABA. Nicotine also raised the membrane potential and the intracellular calcium concentration. These effects were specific, since they were reversed by hexamethonium, an antagonist of the nicotinic receptor. It was shown that L, N, and P/Q type Ca2+ channels are involved in nicotine-mediated Ca2+ entry into cortical neurons. Evaluation of the effects of nicotine on Ca2+ entry in isolated cells showed that 100% of the cells responded to nicotine, although the intensity of the response was variable: 63% of the neurons showed an increase in intracellular Ca(2+) of 152 +/- 5 grey levels, 25% of 88 +/- 12 grey levels and 12% of 48 +/- 1 grey levels. Tetrodotoxin, which blocks voltage-dependent Na(+) channels, completely reversed nicotine-induced Ca2+ entry into single cells. This suggests that the Ca2+ increment is mediated by opening of Ca2+ channels and not by the nicotinic receptor.

[Risperidone: a real alternative for patients treated with depot neuroleptics]

OBJECTIVE

to determine the efficacy and tolerability of risperidone in schizophrenic outpatients.

MATERIAL AND METHOD

DESIGN

multicentre, observational, 6 month follow-up study.

PATIENTS

421 schizophrenic (ICD-10 criteria) outpatients previously treated with depot neuroleptics and who were switched from depot medication to risperidone due to inefficacy and/or low tolerability.

ASSESSMENT

BPRS, CGI, GAF, UKU, and DAI were administered at baseline and months 1, 3, and 6.

STATISTICAL ANALYSIS

the Wilcoxon's T, Friedman's test, and Cochran's Q have been employed.

RESULTS

Mean total dose of risperidone: 5.5 mg/d (SD 2.4). Scores on BPRS, CGI, GAF, UKU, DAI showed statistically significant improvements (p<0.0001). Significant decrease in the proportion of patients using anticholinergic drugs to control extrapyramidal symptoms and in the rate of hospitalizations.

CONCLUSIONS

patients benefited from the change to risperidone in terms of efficacy, tolerance, compliance and admissions. Depot neuroleptic treated schizophrenic patients can benefit from treatment change to an oral atypic antipsychotic like risperidone to ease compliance, illness outcome and patient community integration.

[Interpretation of health-related quality of life of patients on replacement therapy in end-stage renal disease]

STATEMENT: Older age is associated with a worse Health-Related Quality of Life (HRQOL) in patients with End-Stage Renal Disease (ESRD). The aim of this study is to demonstrate that differences on HRQOL between two groups of patients, defined according to age (< 65 years and > or = 65 years or elderly), change according to the form in which the results are analysed.

METHODS

We evaluated the HRQOL of 170 patients undergoing hemodialysis and 210 transplant patients from Asturias (Spain), using the SF-36 Health Survey. Sociodemographic and clinical data, Karnofsky Scale and a Comorbidity Index were also collected. The raw scores of the SF-36 and the standardised scores according to age and gender were employed.

RESULTS

The majority of elderly patients on hemodialysis lived alone, constituted a smaller percentage on the transplant waiting list, had a lower serum albumin and lower score of the Karnofsky Scale, than patients under 65 years. No differences were found in transplant patients. The raw scores on the SF-36 were less for the elderly patients on hemodialysis and transplant. The raw scores for elderly undergoing hemodialysis were less than those obtained by the general population, and raw scores for elderly transplant patients were similar or slightly greater. The standardized scores of the SF-36 were greater for the elderly in both treatment groups.

CONCLUSIONS

Important differences exist in the evaluation of HRQOL differences between the two groups of age according to the method of analysing the results. The HRQOL of elderly patients is better than that of patients under 65 years of age.

Seroprevalence of HIV and HTLV in a representative sample of the Spanish population

HIV and HTLV seroprevalence was determined by means of unlinked anonymous testing of 2144 sera, originally obtained from primary care patients by representative sampling of the Spanish population aged 15-39 years in 1996. HIV-1 seroprevalence was 4.3 per 1000 population in the 15-39 years age group [95% confidence interval (CI), 1.5-10.7] and 5.6 per 1000 (95% CI, 1.8-15.3) in the 20-39 years age group. Seroprevalence proved higher in males and urban residents. No antibodies to HIV-2 and HTLV-I were detected in any of the sera studied. However, presence of antibodies to HTLV-II was confirmed in one serum sample, while HTLV seroreactivity, though detected in another, could not be typed. The two HTLV-positive results equated to a seroprevalence of 1.9 per 1000 in the 20-39 years age group (95% CI, 0.3-8.6). HIV-I seroprevalence was consistent with previous estimates yielded by back-calculation. The level of HTLV seroprevalence found suggests endemicity.

Biological roles of two new murein hydrolases of Streptococcus pneumoniae representing examples of module shuffling

We have found two murein hydrolases (LytB and LytC) tightly bound to the cell envelope that have completely changed the domain building plan previously reported for the murein hydrolases of Streptococcus pneumoniae. The active center of LytB and LytC is located at the C-terminal, whereas the binding domain is at the N-terminal. LytC has been characterized as the first lysozyme of S. pneumoniae and behaves as an autolysin at 30 degrees C. LytB appears as the main hydrolase responsible for cell separation since inactivation of lytB leads to the formation of long chains of more than 100 cells. These findings indicate that genetic adaptation of mobile domains is extremely efficient in pneumococcus.

[Evaluation of the psychometric properties of the Spanish version of 5 questionnaires for the evaluation of post-traumatic stress syndrome]

AIM

To determine the psychometric properties of the Spanish versions of the following scales for assessing PTSD patients: TQ, CAPS-DX, DTS, TOP-8, and DGRP.

METHODS

Data from 63 PTSD patients and 23 healthy subjects were analysed. Internal consistency and test-retest reliability (after 15 days) were calculated. Convergent validity was analysed by correlating subjects' scores with the number of symptoms (DSM-IV) and scores on the CGI scale. Discriminative capability was analysed by comparing TQ, CAPS-DX, DTS, TOP-8, and DGRP patients' scores with scores from healthy subjects, and between patients' subgroups according to the presence or absence of psychiatric comorbidity and to the degree of severity as determined by the CGI-S.

RESULTS

CAPS-DX, DTS, TOP-8, and DGRP showed an adequate internal consistency (Cronbach alpha: 0.74-0.91) and all of them obtained ICC between 0.77 and 0.93. The five questionnaires were able to discriminate between patients and healty subjects, and between the patients' subgroups.

CONCLUSIONS

The Spanish versions of the TQ, CAPS-DX, DTS, TOP-8, and DGRP have shown adequate reliability and validity for assessing PTSD patients in daily clinical practice. CAPS-DX seems to be more adequate a diagnostic and DTS a severity rating scale.

Dose-response relationships. A model for describing interactions, and its application to the combined effect of nisin and lactic acid on Leuconostoc mesenteroides

As well as producing bacteriocins, many lactic bacteria produce other potentially toxic compounds or growth inhibitors, especially lactic acid, which may interfere in the assays commonly used to quantify these peptides. A systematic set of modifications is proposed which, when applied to the logistical equation, enable it to describe the combined (but not additive) effects of two or more active principles. The general model thus derived is applied to the interaction of nisin and lactic acid on Leuconostoc mesenteroides.

[Factors associated with health related quality of life in patients undergoing renal replacement therapy]

The aim of this study was to investigate the sociodemographic and clinical variables which influence health-relate quality of life (HRQOL) of patients on renal replacement therapy (RRT). A cross-sectional study was carried out with a sample including all patients on hemodialysis (n = 170) and transplant patients (n = 210) of our region. The HRQOL assessment instruments used in this study were: the Spanish versions of the sickness impact profile (SIP) and the SF-36 health survey (SF-36). Sociodemographic and clinical data (including age at start of RRT, age at the interview, gender, hospital, socioeconomic level, educational level, living conditions, inclusion in transplant waiting list, renal disease diagnosis, time in any RRT, hemoglobin, hematocrit, serum urea, creatinine, proteins and albumin, hospital admissions and length of hospital stay during last year), a comorbidity index and the Karnofsky performance scale score step. To investigate which studied variables had independent influence over the HRQOL measures, logistic regression method was employed in the case of the SF-36, and multiple regression, in the case of the SIP. A model was adjusted step by step in each RRT method (hemodialysis and transplantation) for each dimension of the PCE (physical dimension, psychosocial dimension and total score), and for each component summary score of the SF-36 (physical and mental component summary). In patients on hemodialysis, variables associated with better HRQOL were: higher age, female gender, higher educational level, and better functional status; and variables associated with worse HRQOL were: higher number of hospital admissions, and higher comorbidity index. In transplant patients, variables associated with better HRQOL were: higher age and higher functional status; and variables associated with worse HRQOL were: longer time on dialysis before transplant, longer time with functioning transplant, and higher comorbidity index. Despite the independent influence on the HRQOL demonstrated for some of the studied variables, it seems that HRQOL assessment instruments scores may mainly depend on other non-studied variables, and it may be that these instruments evaluate other aspects of the patients which have not been taken into account until now.

A method for bacteriocin quantification

Different aspects of the most commonly used assay methods in the study of bacteriocins were examined. The conditions under which extraction and incubation (including exposure time) take place were analysed, and several different formal models that are usually employed to calculate ID50 were compared. As an alternative designed to overcome the problems which characterize the response of micro-organisms that are sensitive to bacteriocins, an operative procedure in a liquid medium and a modified re-parameterized logistic equation is proposed. When applied to the inhibition of Leuconostoc mesenteroides by nisin, the model allows an optimal experimental procedure to be defined.

Idiopathic chondrolysis of the hip: long-term evolution

Idiopathic chondrolysis of the hip is characterized by the destruction of the articular cartilage due to an unknown cause, principally affecting women during adolescence and producing premature degeneration of the hip. Twelve cases (11 patients) were reviewed at our hospital, with an average follow-up period of 13.2 years, during which a clinical and radiologic study was performed. Despite the treatment implemented, idiopathic chondrolysis of the hip causes progressive degeneration of the joint with the appearance of almost constant pain, stiffness, and anomalous positions. Radiologic studies show concentric narrowing of the articular space, decrease in the width of the femoral head and neck, and shortening of the affected member due to alteration in the growth physis of the upper extremity of the femur.

[Quality of life and disability in chronic schizophrenics treated with with risperidone and previously treated with depot neuroleptics]

OBJECTIVES

1. Assess the evolution of disability and quality of life in schizophrenic patients treated with risperidone and who had received depot neuroleptics; 2. Evaluate risperidone efficiency; 3. Evaluate safety of this drug.

METHOD

Post-marketing multicentric observational (8 months) surveillance study was carried out.

PATIENTS

109 schizophrenic patients (ICD-10 criteria).

ASSESSMENTS

baseline and months 2, 4 and 8.

INSTRUMENTS

SF-36, WHO/DDS-S, BPRS and CGI. Safety was evaluated by the UKU subscale for neurological side effects and spontaneous reports.

RESULTS

statistically significant improvement of the mean scores of BPRS, CGI, WHO/DDS-S and SF-36 at 2, 4 and 8 months. There was a significant reduction in the total UKU subscale for neurological side effects scores from visit 1 (month 2) onwards. Risperidone was generally well tolerated by the study patients. From a total of 104 patients included, only 4 (3.8%) discontinued treatment due to adverse reactions. During the 8 months of study period, 87.6% of the patients did not suffer any adverse event; the resting 12.4 suffered one or more side effects. The most frequently reported adverse events according spontaneous reports were: anxiety and restlessness (n= 4; 3.8%), weight increase (n= 4; 3.8%), sexual disturbances (n= 4; 3.8%) and amenorrhea (n= 2; 1.9%) among others.

CONCLUSION

the long-term treatment with risperidone has improved the disability and quality of life levels of a large group of schizophrenic patients previously treated with depot neuroleptics.

[Validation of the Spanish version of the Liebowitz social anxiety scale, social anxiety and distress scale and Sheehan disability inventory for the evaluation of social phobia]

BACKGROUND

Social phobia is an anxiety disorder of increasing interest in clinical psychiatric practice and research. The questionnaires most widely used in the psychometric evaluation of these patients are: Liebowitz Social Anxiety Scale (LSAS), Social Anxiety and Distress Scale (SADS) and Sheehan Disability Inventory (SDI). The objective of this study was to evaluate the validity and reproducibility of the Spanish versions.

SUBJECTS AND METHODS

Convergent validity was analysed by correlating patients' scores on the LSAS, SADS and SDI with scores on the Global Activity Evaluation Scale (GAES), the Hamilton Anxiety Scale (HAM-A) and the Visual Analogue Scale (VAS) of the EuroQol. Validity of the internal structure was examined by analysing the correlations between the different sub-escales of the questionnaires. Internal consistency was analysed using Cronbach's alpha and Kuder-Richardson coefficients. Discriminative capability was analysed by comparing LSAS, SADS and SDI scores of patients with social phobia with scores from healthy subjects, and with that obtained on the HAM-A and the EuroQol VAS. Reproducibility was analysed by re-testing patients after 15 days.

RESULTS

57 patients and 57 healthy subjects were recruited in 4 psychiatric centres. The three questionnaires showed an adequate convergent validity with the GAES, the HAM-A and the EuroQol VAS (r = -0.24-0.40 and r = 0.29-0.52). The LSAS and SDI questionnaires showed a homogenous internal structure in terms of correlation between sub-scales (r = -0.61-0.93 for LSAS, and r = -0.04-0.61 for SDI). All the sub-scales of the questionnaires showed an adequate internal consistency (with coefficients between 0.72 and 0.88). The questionnaires discriminated between groups of patients with different levels of symptom severity and self-perceived overall health. They also discriminated between patients with social phobia and healthy subjects (area under the Receiver's Operating Characteristics curves = 0.95-0.99). All sub-scales from the questionnaires showed adequate reproducibility (with intraclass correlation coefficients between 0.63 and 0.88).

CONCLUSIONS

The Spanish versions of the LSAS, SADS and SDI questionnaires have shown adequate validity and reproducibility for use in clinical research and the clinical assessment of patients with social phobia in Spain.

[Validation of the Spanish version of the social adaptation scale in depressive patients]

INTRODUCTION

The Social Adaptation Self-evaluation Scale (SASS) allows a very easy evaluation of the individual's perspective about himself and his environment, together with his behaviour and social motivation. Taking into account that social maladjustment is high prevalent and well documented for depressed subjects and it is one of the most limiting aspects of their global performance, the aim of the present work is to validate the Spanish version of SASS for its application in subjects diagnosed as suffering major depression (DSM-IV).

METHODOLOGY

A cross sectional multicentre study was carried out by collecting information on 464 patients (34.7% men and 65.3% women range 18 to 65 years), which included their answers to the scale and relevant sociodemographic and clinical variables.

RESULTS

The principal component analysis corroborated the identification of 4 main factors: the first one being extrafamily relationships (31.4% of inertia); the second, work and leisure (7.6% of inertia); the third, social and cultural interests (5.6% of inertia); and the fourth factor, family relationships and behavioral strategies (5.5% of intertia). The scale has provided adequate reliability and validity indexes as well as sensitivity to the severity of the depressive episode.

CONCLUSIONS

The Spanish version of the SASS has proven to be an adequate instrument for evaluating social adjustment in depressive subjects. However, future studies must corroborate its sensitivity to the effects of antidepressant treatment and potential differences between the antidepressant agents employed.

Mechanism by which GABA, through its GABA(A) receptor, modulates glutamate release from rat cortical neurons in culture

In cortical neurons, the GABA(A) agonist, muscimol, increases: (a) basal glutamate release (with a EC50 of 99 +/- 7 microM); (b) intracellular calcium and (c) membrane potential, all of these in a dose-dependent manner. These muscimol effects were specific since they were reversed by bicuculline, a GABA(A) antagonist. When the action of muscimol was measured at different KCl concentrations, an increase or decrease of the glutamate secretion was observed, depending on the KCl concentration in the medium. At low KCl concentration (5.6 mM of KCl), it depolarized, at 20 mM of KCl it had no effect, but at higher KCl concentrations (30-100 microM of KCl), it produced a hyperpolarization in these cells. The mechanism by which the GABA-Cl(-)-channel permits Cl- fluxes, inward or outward, depending on the membrane potential.

[Long term evolution of the incapacity in schizophrenic patients in maintenance treatment with risperidone]

OBJECTIVE

To determine the evolution of the degree of long term disability (8 months) in a group of schizophrenic outpatients undergoing monotherapy with risperidone. DESIGN, An observational multicentre study of 8 months follow up.

PATIENTS

354 patients with schizophrenic disorder (ICD-10).

EVALUATION

Baseline, 2, 4 and 8 months.

INSTRUMENTS

BPRS, CGI, UKU, WHO/DAS-S.

RESULTS

a significant decrease in both the global scores and in each of the 4 areas of disability. Improvement in disability depends to a large degree on the improvement of the disorder as shown on the BPRS and CGI. After 8 months, those patients with paranoid subtype and the less severe ones (BPRS and CGI) showed a considerably lesser degree of disability. The final level of disability (square root = 0,61) is narrowly related to the baseline level of disability, the 3 clusters of the final BPRS, the final CGI, gender and the subtype of schizophrenia.

Effect of glutamate receptor agonists on catecholamine secretion in bovine chromaffin cells

In this study, the effects of glutamate and glutamate receptor agonists in cultured chromaffin cells from bovine adrenal medulla were investigated. It was found that glutamate increases basal catecholamine (CA) secretion in a dose-dependent manner. This effect is mimicked by specific agonists of the four known glutamate receptors N-methyl-D-aspartate (NMDA), quisqualate/(RS)-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainate (KA), and trans-(+)-1-amino-1,3-cyclopentane dicarboxylic acid (t-ACPD), which increased both basal and nicotine-evoked CA secretion. The NMDA receptor antagonist 2-amino-5-phosphonopentanoic acid, 6-cyano-7-nitroquinoxaline-2,3-dione, an antagonist of KA and AMPA receptors, and L-(+)-2-amino-3-phosphonopropionic acid, an antagonist of the t-ACPD receptor, inhibited the stimulatory effect of related glutamate agonists. Hexamethonium, an antagonist of the nicotinic receptor, failed to influence glutamate agonists except for a 15% inhibition of KA. The increase in CA secretion produced by a 100 microM concentration of glutamate agonists was about 20-60% of that obtained with 10 microM of nicotine, an agonist of the physiological stimulatory cholinergic receptor. The increase in CA secretion produced by glutamate was accompanied by both an increase in bisoxonol fluorescence, suggesting membrane depolarization, and by an increase in intracellular Ca2+ concentrations. Results obtained with image analysis on single cells indicated that the percentage of cells which respond to the stimulation of 50 microM of glutamate is 42%. From these results, we conclude that glutamate, through its four known glutamate receptors, can increase both basal and nicotine-evoked CA secretion in chromaffin cells by a process which involves membrane depolarization and an increase in intracellular calcium levels.

Segregation of nitric oxide synthase expression and calcium response to nitric oxide in adrenergic and noradrenergic bovine chromaffin cells

Previous work has demonstrated that nitric oxide can be an important intracellular messenger in the regulation of neurosecretion in chromaffin cells. Since standard chromaffin cell cultures are mixed populations of noradrenaline and adrenaline producing cells, it would seem important to understand the functional differences between these individual components. The use of fluorescence imaging techniques for the recording of cytosolic calcium from single chromaffin cells together with the immunoidentification of individual cells with specific antibodies against tyrosine hydroxylase, N-phenyl ethanolamine methyl transferase and nitric oxide synthase, has allowed us to measure single-cell calcium responses in identified adrenergic, noradrenergic and nitrergic chromaffin cells, thus helping us to clarify the differential role of nitric oxide in the function of these chromaffin cell types. 53 +/- 2% of chromaffin cells were able to synthesize nitric oxide (nitric oxidesynthase-positive cells), these cells being mainly noradrenergic (82 +/-2%). Results indicate that nitric oxide donors such as sodium nitroprusside, molsidomine and isosorbide dinitrate evoke [Ca2+]i increases in a 62 +/- 4% of chromaffin cells, the response to nitric oxide donors being between 30 and 50% of that of 20 microM nicotine. Cells responding to nitric oxide donors were mainly adrenergic (68 +/- 5%) although 45 +/- 9% of noradrenergic cells also gave [Ca2+]i increasing responses. The distribution of nitric oxide responding cells between nitric oxide synthase-positive and negative was very similar in the whole population (63 +/- 5 and 60 +/- 7%, respectively), but these differences were more prominent when considering the distribution of nitric oxide response between noradrenergic and adrenergic nitric oxide synthase-positive cells; while 73 6% of adrenergic nitric oxide synthase-positive cells evoke [Ca2+]i increases by nitric oxide stimulation, only 35 +/- 11% of noradrenergic nitric oxide synthase-positive cells respond. Taken together these results seem to indicate that (i) nitric oxide could act within adrenal medulla as both an intracellular and intercellular messenger; and (ii) noradrenergic cells seem to be specialized in nitric oxide synthesis while adrenergic cells with an endocrine function could mainly act as a target of neurosecretory action of this second messenger.