Attenuated prefrontal activation during decision-making under uncertainty in schizophrenia: a multi-center fMRI study

Decisions are called decisions under uncertainty when either prior information is incomplete or the outcomes of the decision are unclear. Alterations in these processes related to decisions under uncertainty have been linked to delusions. In patients with schizophrenia, the underlying neural networks have only rarely been studied. We aimed to disentangle the neural correlates of decision-making and relate them to neuropsychological and psychopathological parameters in a large sample of patients with schizophrenia and healthy subjects. Fifty-seven patients and fifty-seven healthy volunteers from six centers had to either indicate via button-press from which of two bottles red or blue balls were drawn (decision-making under uncertainty condition), or indicate whether eight red balls had been presented (baseline condition) while BOLD signal was measured with fMRI. Patients based their decisions on less conclusive evidence and had decreased activations in the underlying neural network, comprising of medial and lateral frontal as well as parietal areas, as compared to healthy subjects. While current psychopathology was not correlated with brain activation, positive symptoms led to longer decision latencies in patients. These results suggest that decision-making under uncertainty in schizophrenia is affected by a complex interplay of aberrant neural activation. Furthermore, reduced neuropsychological functioning in patients was related to impaired decision-making and task performance was modulated by distinct positive symptoms.

Do different fairness contexts and facial emotions motivate 'irrational' social decision-making in major depression? An exploratory patient study

Although 'irrational' decision-making has been linked to depression, the contribution of biases in information processing to these findings remains unknown. To investigate the impact of cognitive biases and aberrant processing of facial emotions on social decision-making, we manipulated both context-related and emotion-related information in a modified Ultimatum Game. Unfair offers were (1) paired with different unselected alternatives, establishing the context in which an offer was made, and (2) accompanied by emotional facial expressions of proposers. Responder behavior was assessed in patients with major depressive disorder and healthy controls. In both groups alike, rejection rates were highest following unambiguous signals of unfairness, i.e. an angry proposer face or when an unfair distribution had deliberately been chosen over an equal split. However, depressed patients showed overall higher rejection rates than healthy volunteers, without exhibiting differential processing biases. This suggests that depressed patients were, as healthy individuals, basing their decisions on informative, salient features and differentiating between (i) fair and unfair offers, (ii) alternatives to unfair offers and (iii) proposers' facial emotions. Although more fundamental processes, e.g. reduced reward sensitivity, might underlie increased rejection in depression, the current study provides insight into mechanisms that shape fairness considerations in both depressed and healthy individuals.

Change of phase-solubility behavior by gamma-cyclodextrin derivatization

The effect of γ-cyclodextrin and its four derivatives on the solubility of progesterone in phosphate buffer pH 7.4 was investigated. γ-Cyclodextrin forms a complex precipitating from solution at low cyclodextrin concentrations. No precipitation of complexes was observed with the γ-cyclodextrin derivatives. This change in phase-solubility behavior is probably due to low crystallization tendencies of the derivatives.

[Determinants of direct cost in schizophrenia patients with persistent positive symptoms]

OBJECTIVE

To analyze direct costs and cost determinants in psychotic patients with persistent positive symptoms (PPS).

METHODS

A total of 330 patients with PPS were recruited via 6 university clinics and interviewed about service utilization in the previous 3 months. After monetary valuation, costs were analyzed via generalized linear mixed models with gamma distribution and log-link function to identify determinants of direct costs.

RESULTS

The mean costs were 7,065 € and resulted predominantly from psychiatric hospital care (63 %), assisted living (17 %) and complementary services (8 %). We found statistically significant associations between direct costs and an increasing score of the negative subscale of the Positive and Negative Syndrome Scale (+ 2,484 € per point, p < 0.001) and experiencing less than one social contact per week (- 2,272 €, p = 0.003).

CONCLUSION

PPS incurred substantial direct costs which primarily resulted from hospital treatment, and were strongly associated with symptom severity.

Structural brain alterations associated with schizophrenia preceded by conduct disorder: a common and distinct subtype of schizophrenia?

Conduct disorder (CD) prior to age 15 is a precursor of schizophrenia in a minority of cases and is associated with violent behavior through adulthood, after taking account of substance misuse. The present study used structural magnetic imaging to examine gray matter (GM) volumes among 27 men with schizophrenia preceded by CD (SZ+CD), 23 men with schizophrenia but without CD (SZ-CD), 27 men with CD only (CD), and 25 healthy (H) men. The groups with schizophrenia were similar in terms of age of onset and duration of illness, levels of psychotic symptoms, and medication. The 2 groups with CD were similar as to number of CD symptoms, lifelong aggressive behavior, and number of criminal convictions. Men with SZ+CD, relative to those with SZ-CD, displayed (1) increased GM volumes in the hypothalamus, the left putamen, the right cuneus/precuneus, and the right inferior parietal cortex after controlling for age, alcohol, and drug misuse and (2) decreased GM volumes in the inferior frontal region. Men with SZ+CD (relative to the SZ-CD group) and CD (relative to the H group) displayed increased GM volumes of the hypothalamus and the inferior and superior parietal lobes, which were not associated with substance misuse. Aggressive behavior, both prior to age 15 and lifetime tendency, was positively correlated with the GM volume of the hypothalamus. Thus, among males, SZ+CD represents a distinct subtype of schizophrenia. Although differences in behavior emerge in childhood and remain stable through adulthood, further research is needed to determine whether the differences in GM volumes result from abnormal neural development distinct from that of other males developing schizophrenia.

The impact of alcohol dependence on social brain function

The impact of alcoholism (ALC) or alcohol dependence on the neural mechanisms underlying cognitive and affective empathy (i.e. the different routes to understanding other people's minds) in schizophrenic patients and non-schizophrenic subjects is still poorly understood. We therefore aimed at determining the extent to which the ability to infer other people's mental states and underlying neural mechanisms were affected by ALC. We examined 48 men, who suffered either from ALC, schizophrenia, both disorders or none of these disorders, using functional magnetic resonance imaging while performing on a mind reading task that involves both cognitive and affective aspects of empathy. Using voxel-based morphometry, we additionally examined whether between-group differences in functional activity were associated with deficits in brain structural integrity. During mental state attribution, all clinical groups as compared with healthy controls exhibited poor performance as well as reduced right-hemispheric insular function with the highest error rate and insular dysfunction seen in the schizophrenic patients without ALC. Accordingly, both behavioral performance and insular functioning revealed schizophrenia × ALC interaction effects. In addition, schizophrenic patients relative to non-schizophrenic subjects (regardless of ALC) exhibited deficits in structural integrity and task-related recruitment of the left ventrolateral prefrontal cortex (vlPFC). Our data suggest that ALC-related impairment in the ability to infer other people's mental states is limited to insular dysfunction and thus deficits in affective empathy. By contrast, mentalizing in schizophrenia (regardless of ALC) may be associated with insular dysfunction as well as a combination of structural and functional deficits in the left vlPFC.

Particle size, surface hydrophobicity and interaction with serum of parenteral fat emulsions and model drug carriers as parameters related to RES uptake

Fat emulsions for parenteral nutrition, stabilized by egg lecithin, were characterized in terms of parameters relevant to uptake by the reticuloendothelial system (RES), e.g. size distribution, surface hydrophobicity and adsorption of serum components as a measure of the degree of opsonization. Adsorption of serum components was quantified by zeta potential measurement. Fat emulsions for nutrition were compared with emulsions used for drug delivery and model drug carries for intravenous injection. The emulsions for drug delivery were stabilized by the blockcopolymers Poloxamer 188 and 407 (Pluronic F68 and F127) and Poloxamine 908. Model drug carriers were hydrophobic and hydrophilic polystyrene latex particles. Hydrophilic particles were prepared by adsorption of Poloxamine 908 (coating) onto the particle surface. The hydrophobicity and serum protein adsorption decreased from hydrophobic latex particles to egg lecithin emulsions and blockcopolymer emulsions and particles. The data correlated with that in the literature concerning liver uptake in vivo showing complete RES clearance of hydrophobic latex particles, reduced uptake of egg lecithin emulsions and avoidance of RES uptake by Poloxamine 908 coated particles.

Disentangling structural brain alterations associated with violent behavior from those associated with substance use disorders

CONTEXT

Studies aimed at identifying structural brain alterations associated with persistent violent behavior or psychopathy have not adequately accounted for a lifetime history of substance misuse. Thus, alterations in gray matter (GM) volume that have been reported to be correlates of violent behavior and/or psychopathy may instead be related to lifelong substance use disorders (SUDs).

OBJECTIVE

To identify alterations in GM volume associated with violent behavior and those associated with lifelong SUDs.

DESIGN

Cross-sectional study.

SETTING

Participants were recruited from penitentiaries, forensic hospitals, psychiatric outpatient services, and communities in Germany. Structural magnetic resonance imaging was performed at a university hospital.

PARTICIPANTS

Four groups of men were compared: 12 men with SUDs who exhibited violent behavior (hereafter referred to as violent offenders), 12 violent offenders without SUDs, 13 men with SUDs who did not exhibit violent behavior (hereafter referred to as nonoffenders), and 14 nonoffenders without SUDs.

MAIN OUTCOME MEASURES

Voxel-based morphometry was used to analyze high-resolution magnetic resonance imaging scans. Assessments of mental disorders, psychopathy (using the Psychopathy Checklist-Screening Version), aggressive behavior, and impulsivity were conducted by trained clinicians.

RESULTS

Compared with nonoffenders, violent offenders presented with a larger GM volume in the amygdala bilaterally, the left nucleus accumbens, and the right caudate head and with less GM volume in the left insula. Men with SUDs exhibited a smaller GM volume in the orbitofrontal cortex, ventromedial prefrontal cortex, and premotor cortex than did men without SUDs. Regression analyses indicated that the alterations in GM volume that distinguished the violent offenders from nonoffenders were associated with psychopathy scores and scores for lifelong aggressive behavior. The GM volumes of the orbitofrontal cortex and prefrontal cortex that distinguished the men with SUDs from the men without SUDs were correlated with scores for response inhibition.

CONCLUSIONS

These findings suggest that a greater GM volume in the mesolimbic reward system may be associated with violent behavior and that reduced GM volumes in the prefrontal cortex, orbitofrontal cortex, and premotor area characterize men with SUDs.

Absorption of Isosorbide Dinitrate after Administration as Spray, Ointment and Microemulsion Patch. An In-vitro Study Using the Isolated Perfused Bovine Udder

The isolated perfused bovine udder is an in-vitro model, which maintains bovine udder skin with an isolated vasculature in a viable state. Using this in-vitro model, the percutaneous absorption and metabolism of isosorbide dinitrate (ISDN) was studied.

The organ was perfused with gassed Tyrode solution for up to 6 h. A region of udder skin was treated topically with 60 mg ISDN as a spray, 60 mg ISDN as an ointment and with 120mg ISDN as a microemulsion patch of 30 cm2. Spray and ointment were applied onto a skin region of 400 cm2. The concentrations of ISDN and its metabolites isosorbide-2-mononitrate and isosorbide-5-mononitrate were measured in perfusate fractions by capillary column gas-liquid chromatography with electron capture detection.

Following topical administration of the different formulations, ISDN as well as its metabolites were detected in the perfusate fractions, thus demonstrating that ISDN is metabolized by the udder skin in-vitro. A maximum amount of ISDN was absorbed after administration as a spray followed by ointment and microemulsion (5, 2·5 and 1·8 μmol total organic nitrate, respectively). In contrast, the ISDN flux per cm2 skin was significantly higher after administration of the microemulsion (64·4 pmol cm−2 min−1 for the microemulsion compared with 21·9 and 10·2 pmol cm−2 min−1 for spray and ointment).

Cognitive behavioural therapy versus supportive therapy for persistent positive symptoms in psychotic disorders: the POSITIVE Study, a multicenter, prospective, single-blind, randomised controlled clinical trial

BACKGROUND

It has been demonstrated that cognitive behavioural therapy (CBT) has a moderate effect on symptom reduction and on general well being of patients suffering from psychosis. However, questions regarding the specific efficacy of CBT, the treatment safety, the cost-effectiveness, and the moderators and mediators of treatment effects are still a major issue. The major objective of this trial is to investigate whether CBT is specifically efficacious in reducing positive symptoms when compared with non-specific supportive therapy (ST) which does not implement CBT-techniques but provides comparable therapeutic attention.

METHODS/DESIGN

The POSITIVE study is a multicenter, prospective, single-blind, parallel group, randomised clinical trial, comparing CBT and ST with respect to the efficacy in reducing positive symptoms in psychotic disorders. CBT as well as ST consist of 20 sessions altogether, 165 participants receiving CBT and 165 participants receiving ST. Major methodological aspects of the study are systematic recruitment, explicit inclusion criteria, reliability checks of assessments with control for rater shift, analysis by intention to treat, data management using remote data entry, measures of quality assurance (e.g. on-site monitoring with source data verification, regular query process), advanced statistical analysis, manualized treatment, checks of adherence and competence of therapists. Research relating the psychotherapy process with outcome, neurobiological research addressing basic questions of delusion formation using fMRI and neuropsychological assessment and treatment research investigating adaptations of CBT for adolescents is combined in this network. Problems of transfer into routine clinical care will be identified and addressed by a project focusing on cost efficiency.

DISCUSSION

This clinical trial is part of efforts to intensify psychotherapy research in the field of psychosis in Germany, to contribute to the international discussion on psychotherapy in psychotic disorders, and to help implement psychotherapy in routine care. Furthermore, the study will allow drawing conclusions about the mediators of treatment effects of CBT of psychotic disorders.

Release of gentamicin sulphate from biodegradable PLGA-implants produced by hot melt extrusion

For a long-term local treatment of osteomyelitis biodegradable poly(lactic-co-glycolic acid) (PLGA) implants loaded with gentamicin sulphate (GS) were prepared, analysed and compared to the marketed product Septopal (Biomet, Darmstadt, Germany), which consists of polymethylmethacrylate (PMMA) beads loaded with the same active ingredient. The implants were manufactured by hot melt extrusion with a twin screw extruder. In order to decrease the processing temperature and to improve the drug release behaviour, polyethylene glycol 400 (PEG 400) was added as plasticizer in different concentrations. The glass transition temperature of PLGA measured by differential scanning calorimetry declined in the same manner as the extrusion temperature with increasing PEG 400 concentration. The extrudates of all batches exhibited good encapsulation efficiency between 85% and 115% of the specified content. The behaviour of the implants during exposure to a release medium were characterised by scanning electron microscopy, gravimetric analysis and finally in vitro drug release studies. The results suggest that drug liberation is not affected by the addition of PEG 400, and depends on the drug-PLGA ratio only. Extrudates with 25% GS showed a release pattern with an initially higher drug release followed by a zero order kinetic for about four weeks and showed release profiles equivalent to Septopal.

Measurement of ERK 1/2 in CSF from patients with neuropsychiatric disorders and evidence for the presence of the activated form

The clinical diagnosis of neurodegenerative disorders can be supported by soluble biomarkers in cerebrospinal fluid (CSF), such as tau protein, phospho-tau, and amyloid-beta peptides. In particular, increased CSF levels of phospho-tau in Alzheimer's disease appear to reflect disease specific pathological processes. We report here evidence for the presence of soluble MAP-kinase ERK1/2 in a small set of human CSF samples from patients with Alzheimer's disease, frontotemporal degeneration, and mild cognitive impairment. The level of total ERK1/2 in CSF as measured by electrochemiluminescent assay was correlated with that of total tau and phospho-tau. A small fraction of ERK1/2 in a pooled CSF sample was found to be in the doubly phosphorylated (activated) state. Our findings suggest that i) MAP kinase ERK1/2 is apparently released under neurodegenerative conditions in parallel with tau and phospho-tau and ii) in the future, it might be possible to find in CSF samples evidence for disease related alterations in brain kinase signaling pathways by use of highly sensitive and activation-state specific anti-kinase antibodies.

Treatment effects of serotonergic and noradrenergic antidepressants on the intensity dependence of auditory ERP components in major depression

The intensity dependent amplitude change of auditory evoked potentials (IDAP), an assumed indicator of the level of central nervous serotonergic neurotransmission, was measured in major depressive disorder (MDD, DSM-IV: 296.2, 296.3; APA 1994) before and after treatment with either a selective serotonin reuptake inhibitor or a selective noradrenaline reuptake inhibitor antidepressant and compared with the results of a healthy control group. Auditory evoked P1, N1, P2, P1/N1 and N1/P2 peak-to-peak amplitudes were evaluated in 26 in-patients with MDD prior to and after antidepressant treatment with citalopram (24 days, n=14) or reboxetine (25 days, n=12), and in 43 healthy control subjects. Clinical symptoms of MDD were assessed by means of standardized psychiatric rating scales (CGI, HDRS, HAMA and BDI). The IDAP within the control group remained stable over 24 days (N1 amplitude slope retest ANOVA p=.79). Neither applied antidepressants nor decrease of HDRS total score during treatment had a significant effect on the IDAP in the patients' sample. The conclusion that the IDAP does not reflect the temporary depressive state in MDD is discussed.

Auditory target processing in methadone substituted opiate addicts: the effect of nicotine in controls

BACKGROUND

The P300 component of the auditory evoked potential is an indicator of attention dependent target processing. Only a few studies have assessed cognitive function in substituted opiate addicts by means of evoked potential recordings. In addition, P300 data suggest that chronic nicotine use reduces P300 amplitudes. While nicotine and opiate effects combine in addicted subjects, here we investigated the P300 component of the auditory event related potential in methadone substituted opiate addicts with and without concomitant non-opioid drug use in comparison to a group of control subjects with and without nicotine consumption.

METHODS

We assessed 47 opiate addicted out-patients under current methadone substitution and 65 control subjects matched for age and gender in an 2-stimulus auditory oddball paradigm. Patients were grouped for those with and without additional non-opioid drug use and controls were grouped for current nicotine use. P300 amplitude and latency data were analyzed at electrodes Fz, Cz and Pz.

RESULTS

Patients and controls did not differ with regard to P300 amplitudes and latencies when whole groups were compared. Subgroup analyses revealed significantly reduced P300 amplitudes in controls with nicotine use when compared to those without. P300 amplitudes of methadone substituted opiate addicts were in between the two control groups and did not differ with regard to additional non-opioid use. Controls with nicotine had lower P300 amplitudes when compared to patients with concomitant non-opioid drugs. No P300 latency effects were found.

CONCLUSION

Attention dependent target processing as indexed by the P300 component amplitudes and latencies is not reduced in methadone substituted opiate addicts when compared to controls. The effect of nicotine on P300 amplitudes in healthy subjects exceeds the effects of long term opioid addiction under methadone substitution.

The intensity dependence of auditory ERP components in unmedicated patients with major depression and healthy controls. An analysis of group differences

BACKGROUND

The intensity dependent amplitude change (IDAP) of auditory evoked Event Related Potential (ERP) components has been found to correlate with the level of central serotonergic neurotransmission and to be associated with response to certain antidepressants. However, it is currently unknown whether there is a general abnormality of the IDAP in patients with major depression. Therefore, the purpose of the present study was to compare the IDAP in unmedicated depressed patients with that of healthy control subjects.

METHODS

We report the results of a study evaluating the change of auditory evoked P1, N1, P2 as well as P1/N1 and N1/P2 peak to peak amplitudes in 34 in-patients with major depressive episode prior to antidepressant treatment, and 44 healthy control subjects. Clinical symptoms of depression were assessed by means of standardized psychiatric rating scales (CGI, HDRS, HAMA and BDI).

RESULTS

In multivariate analyses of variance we found no group differences in the intensity dependent increase neither of the P1, N1, and P2 nor of the P1/N1 and N1/P2 peak to peak amplitudes between patients and controls.

CONCLUSIONS

Our data revealed no general abnormality of the IDAP in patients with major depression in comparison to healthy control subjects. This result suggests that specific alterations of the IDAP are not to be expected in major depression in general, these may be confined to subgroups of depressed patients.

Neuropsychological assessment of adult patients with attention-deficit/hyperactivity disorder

Adults with persistent attention-deficit/hyperactivity disorder (ADHD) may show cognitive deficits as compared to healthy control subjects. The aim of this study was to compare a sample of adult outpatients with ADHD on medication to healthy controls on a comprehensive neuropsychological assessment battery. Thirty adults with ADHD under stable psychopharmacological treatment and 27 healthy controls matched for age, gender, and IQ were assessed with ten tests measuring performance with regard to attention, memory, executive function, and fine motor control. Lower performance in patients as compared to controls was found in tests of verbal and visual memory, speed of visuo-motor search, set shifting, and divided attention. Indicators of response inhibition and simple response speed were less affected. Adults with ADHD show indicators of lowered cognitive performance under medication. These are related more to memory and attention under high mental load than to response inhibition or simple attention or motor performance.

Neural activation during successful and unsuccessful verbal learning in schizophrenia

Successful and unsuccessful intention to learn words was assessed by means of event-related functional MRI. Eighteen patients with schizophrenia and 15 healthy control participants were scanned while being given two word lists to read and another seven to learn with immediate recall. Neural activation patterns were segregated according to whether words were subsequently recalled or forgotten and these conditions were contrasted with each other and reading. Compared to controls, patients with schizophrenia showed deficits with regard to neural recruitment of right hippocampus and of cerebellar structures during successful verbal learning. Furthermore, a reversal of activated structures was evident in the two groups: Controls showed activation of right frontal and left middle temporal structures during the unsuccessful intention to learn. During successful learning, there was additional activation of right superior parietal lobule. In contrast, patients showed activation of right superior parietal lobule during unsuccessful and successful intention to learn. There were additional frontal and left middle temporal lobe activations during successful learning. We conclude that increased parietal activity may reflect a mechanism which compensates for the lack of hippocampal and cerebellar contributions to verbal learning in schizophrenia.

Neural Encoding Correlates of High and Low Verbal Memory Performance

Neuroimaging studies have indicated involvement of left prefrontal cortex and temporal areas in verbal memory processes. The current study used event-related functional neuroimaging to compare encoding of subsequently recalled and not recalled words in high and low memory performers. Fifteen healthy volunteers were given lists of words to learn with immediate recall and to read as a control condition. High performers reported to have visualized the words whereas low performers used a rehearsal strategy. Compared to reading, unsuccessful encoding was associated with thalamic and left premotor area (BA 6) activity. Comparing successful with unsuccessful learning yielded widespread activity of the left prefrontal and posterior temporal gyrus as well as the left superior parietal lobe in the whole group. Low performers showed activation of the left premotor area throughout learning and additionally of the left middle temporal and parahippocampal gyrus during successful encoding. High performers showed increased activation in the extrastriate cortex throughout learning and additionally in the left parietal post- and paracentral areas as well as in the right precuneus during successful encoding. The results suggest that high verbal memory performance is the result of spatiovisual activation concomitant to imagery and low performance of hippocampal and motor activation, the latter being associated with rehearsal, with a common memory circuit subserving both groups.

A new formulation concept for drugs with poor water solubility for parenteral application

The parenteral application of active substances with poor solubility in water is often bound to the use of stabilizing excipients or surfactants with serious undesired side effects. A new concept is introduced based on a drug concentrate, comprising the active substance dissolved in parenterally acceptable organic solvents, and an aqueous dilution medium, which are mixed in a special mixing device immediately prior to application and thus generating the applicable formulation directly prior to administration. Due to the requirement of formulation stability for only a few minutes, the amount of stabilizing agents can be reduced significantly. It can be shown that model drugs dissolved in a mixture of polyoxyethylen glycol, ethanol and soya lecithin as stabilizer may be mixed to an aqueous glucose solution resulting in a parenterally acceptable and administerable dispersion which is physically stable for several minutes. First in vivo data show good tolerability and blood plasma levels which are comparable to conventional solutions.

The Intensity Dependence of Auditory Evoked ERP Components Predicts Responsiveness to Reboxetine Treatment in Major Depression

INTRODUCTION

The intensity (loudness)-dependent amplitude change (IDAP) of auditory evoked event-related potential (ERP) components has been suggested as an indicator of central serotonergic neurotransmission. In patients with major depression, associations of high IDAP with favorable SSRI treatment outcome have been reported. This is the first study to assess the predictive value of the IDAP in SNRI treatment.

METHODS

We evaluated the pre-treatment intensity-dependent change of auditory evoked P1, N1, P2, and P1/N1 and N1/P2 peak-to-peak amplitudes in 14 inpatients with major depressive episode (DSM IV) in the course of 24 days of treatment with the SNRI reboxetine (6-12 mg/d).

RESULTS

Our data revealed a highly significant correlation between lower intensity-dependent N1 amplitude slopes prior to reboxetine treatment and stronger decrease of HDRS total score at Fz ( r = 0.86, P < 0.001), Fcz ( r = 0.91, P < 0.001), and Cz ( r = 0.93, P < 0.001).

CONCLUSION

This result corroborates the hypothesis of the IDAP as a differential indicator of serotonergic versus noradrenergic antidepressant psychopharmacotherapy.

Vermal atrophy of alcoholics correlate with serum thiamine levels but not with dentate iron concentrations as estimated by MRI

Chronic alcohol consumption is frequently accompanied by cerebellar degeneration. The exact aetiology of alcoholic cerebellar degeneration is still a matter of debate. The aim of the present study was to investigate whether patients with chronic alcohol consumption exhibit a decrease in dentate nuclei intensity as measured by MRI, and if so, whether this decrease correlates with cerebellar atrophy as revealed by MR imaging or with clinical signs of cerebellar ataxia. A decrease in dentate nuclei intensity would indirectly indicate that iron accumulation, and therefore, oxidative stress may play a role in alcoholic cerebellar degeneration. MRI of 45 alcoholics and 44 age and sex-matched healthy control subjects was performed using a 3D-T1-weighted fast low angle shot (FLASH) echo sequence. Signal intensities of the dentate nuclei and cerebellar white matter were bilaterally measured. Planimetric measurements of cerebellar size were performed using a 3D-T1-weighted magnetization prepared rapid acquisition gradient echo (MPRAGE) sequence. Results demonstrated that dentate nuclei intensity was not significantly decreased in patients with chronic alcohol consumption (mean +/- SD signal intensity 65.36 +/- 13.0) if compared with control subjects (mean +/- SD signal intensity 68.95 +/- 9.4) (p = 0.15). Dentate nuclei intensity did not correlate with cerebellar size neither in control subjects nor in alcoholics. In contrast, vitamin B1 level correlated with cerebellar size in alcoholics even if the vitamin B1 concentration was within normal values (r = 0.344, p = 0.028). These results support the view that thiamine deficiency rather than direct neurotoxic effects of alcohol is the main causative factor for the development of alcoholic cerebellar degeneration.

Partial solubility parameters of poly(d,l-lactide-co-glycolide)

During production of microparticles by the polymer incompatibility method a polymer solution is demixed. Therefore, investigations into solubility are often carried out when the suitability of a polymer is examined. Solubility parameters can be used to quantify the solubility. For polylactide and polyglycolide as commonly employed copolymers for microparticles the solubility parameters have rarely been documented. This study aimed to determine solubility parameters and partial solubility parameters for different proportions of lactide to glycolide for poly(D,L-lactide-co-glycolide) (PLGA). The employed methods were compared and solubility maps established. Finally the accuracy of the results was discussed for different polymer batches which were used for production of microparticles. Although the turbidity titration method was found to be the most precise, it was not possible to sufficiently explain the differences between three polymer batches during microparticle production.

The intensity dependence of the auditory evoked N1 component as a predictor of reponse to Citalopram treatment in patients with major depression

The intensity dependence of the auditory evoked N1 ERP component (IDAP) has been suggested as an indicator of central serotonergic neurotransmission with relevance to pharmacological treatment. We report the results of a study evaluating the IDAP in 16 in-patients fulfilling DSM-IV criteria for major depressive episode in the course of treatment with the SSRI Citalopram. Our data revealed a significant correlation between the intensity slopes of the N1 amplitude prior to Citalopram treatment and treatment response: patients with higher intensity slopes of N1 amplitude showed a significantly stronger decrease of HDRS-Score after Citalopram treatment than patients within the lower intensity slope ranges. Our results indicate an association of N1 amplitude intensity dependence with response to antidepressant treatment with Citalopram.