Prepulse inhibition in psychiatric disorders--apart from schizophrenia

Prepulse inhibition (PPI) is a robust operational measure of sensorimotor gating. In schizophrenic patients PPI is deficient. The aim of our review was to investigate the state of science regarding PPI and psychiatric disorders aside from schizophrenia. We used the online database PubMed in order to search for original published reports on PPI studies. The terms "prepulse inhibition", "sensorimotor gating", "blink recovery", and "blink reflex excitability" have been combined with the names of psychiatric disorders. We found that PPI is deficient in obsessive compulsive disorder (OCD) and Gilles de la Tourette's syndrome (GTS). In bipolar disorder dysfunctional PPI seems to be rather state dependent. Studies on depression and attention deficit/hyperactivity disorder (ADHD) consistently report no alterations. Evidence regarding sensorimotor gating in anxiety, autism, fragile X syndrome, posttraumatic stress disorder (PTSD), substance disorders, and Huntington's disease is still poor. There is a strong need for further studies on PPI in psychiatric disorders. PPI is highly applicable for translational research and might also be a very useful tool to investigate the mode of action of innovative, neuro-modulative techniques. Future PPI studies should control for influencing variables such as smoking, sex, or medication.

Monitoring rFVIII prophylaxis dosing using global haemostasis assays

Secondary factor VIII (FVIII) prophylaxis converts severe haemophiliacs (FVIII:C < 1 IU dL(-1)) to a moderate phenotype (FVIII:C ≥ 1 IU dL(-1)), however, plasma FVIII:C is a poor predictor of bleeding risk. This study used thromboelastography (TEG) and thrombin generation assay (TGA) to quantify coagulation across a 48 h rFVIII prophylaxis period. 10 severe haemophiliacs with varying clinical bleeding phenotypes received their standard rFVIII prophylaxis dose and blood samples were obtained over 48 h. Measured parameters included FVIII:C, TEG and TGA at each time point. FVIII:C pharmacokinetics (PK) and correlation between global assay parameters was performed. The FVIII:C PK parameters were consistent with previous literature. There was significant correlation between FVIII:C and TEG R-time and aPTT (both P < 0.001). Significant correlations existed between FVIII:C and TGA peak, ETP and velocity parameters (all P < 0.001). At 24 h the TEG parameters were sub-therapeutic despite median FVIII:C of 13.0 IU dL(-1). TGA was sensitive to FVIII:C below 1 IU dL(-1). Those with the severest bleeding phenotype had the lowest TGA parameters. There was significant correlation between FVIII:C and TEG and TGA. TEG lost sensitivity at 48 h, but not TGA. Prospective studies are needed to determine whether these data can be used to design individualized rFVIII prophylaxis regimens.

[Use of ECT in drug-refractory schizophrenia--a survey of the current literature]

Since its introduction in the 1930s, electroconvulsive therapy (ECT) has maintained an important role as an efficacious and evidence-based somatic treatment option in affective or schizophrenic diseases. As opposed to major depressive disorder, ECT is commonly used to a substantially lesser extent for patients with schizophrenia in the USA, UK and most parts of Europe. Accordingly there is comparably little evidence regarding the clinical effectiveness and tolerability of ECT in schizophrenia. Recent clinical studies, meta-analyses and surveys point to the combination of ECT and antipsychotic medication as being advantageous in the treatment of schizophrenia, particularly in those patients who have shown inadequate responses to psychotropic medication alone. Clinical features considered to be predictive for ECT outcome are delusions, hallucinations, presence of affective and catatonic symptoms and absence of negative symptoms as well as a short duration of the current episode. National and international guidelines suggest ECT as an augmentation strategy in treatment-refractory schizophrenia in acute exacerbation and continuation therapy. Considering the fact that a substantial part of schizophrenic patients does not respond sufficiently to pharmacotherapy there still is a lack of well designed, controlled and randomised clinical trials to improve evidence for the promising role of ECT in schizophrenia.

Pharmacological treatment of deep brain stimulation-induced hypomania leads to clinical remission while preserving motor benefits

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for Parkinson's disease, but can lead to adverse effects including psychiatric disturbance. Little is known about the risk factors and treatment options for such effects. Here, we describe a patient who reproducibly developed stimulation-induced hypomania when using ventrally located electrodes and responded well to pharmacological intervention while leaving the stimulation parameters unchanged to preserve motor benefits. In spite of clinical remission, [¹⁵O]-positron-emission-tomography (PET) demonstrated activation patterns similar to those reported during mania. This case, therefore, highlights an important treatment option of adverse effects of DBS, but also points toward the need for investigations of its risk factors and their underlying neurobiological mechanisms.

Monitoring rFVIIa 90 μg kg⁻¹ dosing in haemophiliacs: comparing laboratory response using various whole blood assays over 6 h

Recombinant FVIIa is a haemostatic agent administered to patients with severe FVIII or FIX deficiency with inhibitors. Although rFVIIa is effective at stopping bleeding, a reliable assay to monitor its effect is lacking. To characterize the pharmacokinetics and global coagulation effects of rFVIIa for 6 h following a IV dose of 90 μg kg⁻¹. Ten non-bleeding subjects with severe FVIII or FIX deficiency were infused with a single-dose of rFVIIa 90 μg k⁻¹ body weight and blood was collected before and at 0.5, 1, 2, 4 and 6 h postdose. Global haemostasis was characterized throughout the study utilizing whole blood analyses (Hemodyne HAS, TEG, ROTEM). The clearance and half-life of factor FVII:C was estimated as 39.0 ± 8.8 mL h⁻¹ kg⁻¹ and 2.1 ± 0.2 h respectively. There was good inter-assay agreement with respect to clot initiation parameters (R, CT and FOT) and these parameters all fell to a mean of approximately 9 min following rFVIIa dosing. The platelet contractile force (PCF) and clot elastic modulus (CEM) were positively correlated to FVII:C (P < 0.0001), and these parameters were dynamic throughout the 6-h period. The MA and MCF did not correlate to FVII:C nor did they significantly change during the study. Prothrombin F1 + 2 significantly increased following rFVIIa dosing (P < 0.001), but remained steady throughout the study. There was no change in D-dimer concentrations over time. The FOT, R and CT characterized clot initiation following rFVIIa dosing. The PCF and CEM were correlated to FVII:C and characterized the dynamics of platelet function and clot strength over the rFVIIa dosing interval. The clinical significance of these findings needs additional study.

Effect of vitamin D supplementation on testosterone levels in men

The male reproductive tract has been identified as a target tissue for vitamin D, and previous data suggest an association of 25-hydroxyvitamin D [25(OH)D] with testosterone levels in men. We therefore aimed to evaluate whether vitamin D supplementation influences testosterone levels in men. Healthy overweight men undergoing a weight reduction program who participated in a randomized controlled trial were analyzed for testosterone levels. The entire study included 200 nondiabetic subjects, of whom 165 participants (54 men) completed the trial. Participants received either 83 μg (3,332 IU) vitamin D daily for 1 year (n = 31) or placebo (n =2 3). Initial 25(OH)D concentrations were in the deficiency range (< 50 nmol/l) and testosterone values were at the lower end of the reference range (9.09-55.28 nmol/l for males aged 20-49 years) in both groups. Mean circulating 25(OH)D concentrations increased significantly by 53.5 nmol/l in the vitamin D group, but remained almost constant in the placebo group. Compared to baseline values, a significant increase in total testosterone levels (from 10.7 ± 3.9 nmol/l to 13.4 ± 4.7 nmol/l; p < 0.001), bioactive testosterone (from 5.21 ± 1.87 nmol/l to 6.25 ± 2.01 nmol/l; p = 0.001), and free testosterone levels (from 0.222 ± 0.080 nmol/l to 0.267 ± 0.087 nmol/l; p = 0.001) were observed in the vitamin D supplemented group. By contrast, there was no significant change in any testosterone measure in the placebo group. Our results suggest that vitamin D supplementation might increase testosterone levels. Further randomized controlled trials are warranted to confirm this hypothesis.

[Variety of symptoms after drug use of gamma-hydroxybutyric acid (GHB)]

Gamma-hydroxybutyric acid (GHB, "liquid ecstasy") and its legal prodrugs gamma-butyrolactone and 1,4-butanediol are gaining importance as recreational drugs in Germany. Because of the wide availability of GHB and its prodrugs physicians are increasingly being confronted with cases of intoxication. The effect of GHB intoxication is comparable with those of alcohol and/or benzodiazepines. Likewise, symptoms of withdrawal may occur. In this review, we summarise current data regarding the history, pharmacodynamics and pharmacokinetics of the drug as well as the relevant symptoms of intoxication or withdrawal as they pertain to neurology and psychiatry.

Enhanced target gene knockdown by a bifunctional shRNA: a novel approach of RNA interference

RNA interference (RNAi) is a natural cellular regulatory process that inhibits gene expression by transcriptional, post-transcriptional and translational mechanisms. Synthetic approaches that emulate this process (small interfering RNA (siRNA), short hairpin RNA (shRNA)) have been shown to be similarly effective in this regard. We developed a novel 'bifunctional' RNAi strategy, which further optimizes target gene knockdown outcome. A bifunctional construct (bi-sh-STMN1) was generated against Stathmin1, a critical tubulin modulator that is overexpressed in human cancers. The bifunctional construct is postulated to concurrently repress the translation of the target mRNA (cleavage-independent, mRNA sequestration and degradation) and degrade (through RNase H-like cleavage) post-transcriptional mRNA through cleavage-dependent activities. Bi-sh-STMN1 showed enhanced potency and durability in parallel comparisons with conventional shRNA and siRNAs targeting the same sequence. Enhanced STMN1 protein knockdown by bi-sh-STMN1 was accompanied by target site cleavage at the mRNA level showed by the rapid amplification of complementary DNA ends (RACE) assay. Bi-sh-STMN1 also showed knockdown kinetics at the mRNA level consistent with its multieffector silencing mechanisms. The bifunctional shRNA is a highly effective and advantageous approach mediating RNAi at concentrations significantly lower than conventional shRNA or siRNA. These results support further evaluations.

[Thrombolytic therapy in conversion disorder with sensorimotor hemisyndrome]

We here report on a 43-year-old man who was repeatedly admitted to our stroke unit with acute onset of sensorimotor hemisyndrome of acute onset. In most cases symptoms ceased shortly after admission, but twice when symptoms persisted thrombolytic therapy was applied. This case demonstrates that in emergency situations a rare differential diagnosis like conversion disorder with sensorimotor deficits may be hard to establish even if the patient presents to the same emergency unit.