Transcranial Direct Current Stimulation (tDCS) for major depression - Interim analysis of cloud supervised technical data from the DepressionDC trial.

BACKGROUND: Transcranial direct current stimulation (tDCS) of prefrontal cortex regions has been reported to exert antidepressant effects, though large scale multicenter trials in major depressive disorder (MDD) supporting this notion are still lacking. Application of tDCS in multicenter settings, however, requires measurement, storage and evaluation of technical parameters of tDCS sessions not only for safety reasons but also for quality control. To address this issue, we conducted an interim analysis of supervised technical data across study centers in order to monitor technical quality of tDCS in an ongoing multicenter RCT in MDD (DepressionDC trial). METHODS: Technical data of 818 active tDCS sessions were recorded, stored in a data cloud, and analysed without violating study blinding. Impedance, voltage and current were monitored continuously with one data point recorded every second of stimulation. RESULTS: Variability of impedance was considerable (1,42 kΩ, to 8,23 kΩ), inter-individually and even more intra-individually, but did not significantly differ between the study centre in Munich and all other sites. CONCLUSION: Measurement, centralized data storage via data cloud and remote supervision of technical parameters of tDCS are feasible and proposed for future RCTs on therapeutic tDCS in multiple settings.

Major histocompatibility complex-expressing nonhematopoietic astroglial cells prime only CD8+ T lymphocytes: astroglial cells as perpetuators but not initiators of CD4+ T cell responses in the central nervous system.

The potential of cells within the central nervous system (CNS) to initiate T lymphocyte responses is not known and was the subject of this study. Using the ability of virgin T lymphocytes to proliferate in a primary response to allogeneic determinants on antigen-presenting cells (APC), we have examined the capacity of major histocompatibility complex (MHC)-expressing astroglial cells to act as stimulators of primary and secondary T cell responses. Neither freshly isolated astrocytes nor primary astrocyte cultures pretreated with interferon gamma (IFN-gamma) to upregulate MHC class I and II expression stimulated unfractionated lymph node (LN) cell populations in the primary mixed lymphocyte reaction. In mixing experiments, astrocytes did not inhibit the T cell response to allogeneic LN stimulators. Purified responder CD4+ T cells also were not stimulated to proliferate or secrete interleukin 2 (IL-2) by MHC class I- and II-expressing astrocytes. In contrast to their inability to stimulate virgin, alloreactive CD4+ T cells, astrocytes were able to specifically stimulate an alloreactive CD4+ T cell line. Unprimed CD8+ T cells, however, exhibited some weak autonomous proliferation to astrocyte stimulators but this response was only substantial in the presence of exogenous IL-2, the latter predominantly being a CD4+ T cell product. Those CD8+ T cells responding in the presence of IL-2 were mainly T cell receptor alpha/beta+ IL-2 receptor (alpha chain)+, and a majority had shifted from high to low CD45R expression. Given the virtual dependence of CD8+ T cells in these studies, on CD4+ T cell help, and the complete absence of activation of this latter subset by astrocytes, it is clear that in the context of this resident CNS cell, further activation of either T cell subset by astrocytes within the CNS can only follow priming by another type of APC. The implications of these results for the induction of T cell responses in the CNS are discussed.

Resident macrophages (ramified microglia) of the adult brown Norway rat central nervous system are constitutively major histocompatibility complex class II positive.

A flow cytometric phenotype for isolated adult central nervous system (CNS) ramified microglia was previously defined (CD45low CD11b/c+) in the Lewis strain rat, that clearly distinguished these cells from all blood-derived leucocytes, the latter being CD45high. Consistent with the reported lack of major histocompatibility complex (MHC) expression in the CNS, isolated microglia were mostly MHC class II-. Employing these phenotypic criteria, we now show that a proportion of microglia in Brown Norway (BN) strain rats are constitutively MHC class II+. In spinal cord, up to 25% of microglia are distinctly positive and most have some level of expression. In situ staining of MHC class II+ microglial cells in BN rats indicates that positive cells are typical of ramified microglia on the grounds of both morphological appearance and anatomical location. In Lewis (LEW) rats, the few MHC class II-expressing cells isolated from the normal CNS are CD45high blood-derived cells and not resident microglia. After infection of both LEW and BN rats with a neurotropic murine hepatitis virus (MHV-JHM), MHC class II was rapidly upregulated on microglia in the BN but not in the LEW strain. In the latter, inflammatory cells were the predominant MHC class II-expressing population. Nevertheless, most microglia in the LEW strain could, after some delay, be induced to express MHC class II after transfer of an experimental autoimmune encephalomyelitis (EAE)-inducing encephalitogenic T cell line. Paradoxically, strains resistant to EAE (exemplified by the BN) contained more constitutive MHC class II-expressing microglia than susceptible ones, when a variety of strains were examined. The results clearly establish that the normal CNS may contain MHC class II-expressing cells that are a resident rather than a transient blood-derived population. It is significant that this expression is strain related, but there is no evidence that microglial cell constitutive MHC class II expression predisposes to EAE susceptibility.

Hydrophilic, pro-drug analogues of T138067 are efficacious in controlling tumor growth in vivo and show a decreased ability to cross the blood brain barrier.

The novel anticancer compound T138067 is an irreversible inhibitor of tubulin polymerization. Amides 3-6 were synthesized using standard methodologies and determined to be significantly less lipophilic than T138067 based on logP calculations. Tubulin polymerization and [(3)H]-T138067 competition assays revealed that these amides are pro-drugs for parent aniline 2. Amides 3-5 showed no detectable signs of crossing the blood brain barrier, while amide 6 was found in extremely small amounts (12 ng/g of brain tissue). Aniline 2, which was formed in vivo from these amides, was found in significantly smaller amounts (approximately 20 to >5000 times) in the brain than when 2 was administered directly. The in vivo efficacy of amide 6 approached that of T138067 and was better tolerated when administered to athymic nude mice bearing MX-1 human mammary tumor xenografts.

Cervical lymphoid tissue but not the central nervous system supports proliferation of virus-specific T lymphocytes during coronavirus-induced encephalitis in rats.

The CD4+ T lymphocyte response in the central nervous system (CNS) and cervical lymph nodes (CLNs) of rats with different susceptibility to coronavirus-induced encephalitis was investigated. The majority of CD4+ T lymphocytes entering the virus-infected CNS in the course of the infection are primed cells that neither proliferate ex vivo nor can be stimulated to proliferation by viral antigens or mitogen in vitro. In contrast, T lymphocytes taken from CLNs of the same animals revealed a strong proliferative response. Restimulation of CLN lymphocytes by viral antigens disclosed a striking difference between the disease-resistant rat strain Brown Norway (BN) and the susceptible Lewis (LEW) strain. Whereas BN lymphocytes responded as early as 5 days post infection, it took more than 11 days until a comparable proliferation was detectable in LEW lymphocytes. From these data we postulate that the majority of T lymphocytes entering the virus-infected brain after sensitisation and expansion in cervical lymph nodes is unresponsive to further proliferation signals and that the kinetics and magnitude of T lymphocyte stimulation in CLNs play an important role in the clinical course of the infection.

Selective screening for the Factor V Leiden mutation: is it advisable prior to the prescription of oral contraceptives?

The cumulative thrombotic risk of Factor V (FV) Leiden and oral contraceptives (OC) recommends screening for the mutation. Assuming that a family history of thrombosis increases the patient's likelihood of bearing FV Leiden, a selective rather than universal screening would be performed. We studied the utility of a family history of thrombosis for screening of FV Leiden before prescription of OC and, furthermore, the utility of screening even if oral contraception is favoured. 101 patients who had their first and single thromboembolic event while using OC were interviewed. 609 women without any history of thromboembolism recruited by gynecologists completed a standard questionnaire. 101 of these women, age-matched and currently using OC, were selected for a case-control study. Regarding patients with previous thromboembolism, a family history in a first-degree relative had a positive predictive value (PPV) of only 14% for FV Leiden. A PPV of 12% was calculated by investigating the 609 thrombosis-free women. Inherited FV Leiden (odds ratio = 4.9) and acquired risk factors (odds ratio = 10.1) were both found to be the most prominent, but independent additional risks. Nevertheless, FV Leiden carriers, both heterozygotes and homozygotes, did not suffer earlier from thromboembolism than patients without the mutation. In conclusion, family history is an unreliable criterion to detect FV Leiden carriers. Screening for factor V Leiden can be worthwhile even if the advantages of oral contraception are higher assessed than the thrombotic risk. Affected women knowing about their additional risk could contribute to the prevention of thrombosis in risk situations.

PIP: The cumulative thrombotic risk of Factor V Leiden (FVL) and oral contraceptive (OC) use raises the possibility of either selective or universal screening for this mutation before OCs are prescribed. Family history of venous thromboembolism as a criterion to detect FVL carriers was evaluated in a case-control study of 101 women from Bavaria, Germany, who had their first and single thromboembolic event while using OCs and 101 healthy age-matched OC users. A questionnaire was administered to a broader group of 609 OC users without a history of thromboembolism. Analysis of the 609 women revealed a 7.4% prevalence of FVL, but no association between this mutation and a family history of thromboembolism. Among women with a previous thromboembolism, a family history in a first-degree relative had a positive predictive value of only 14% for FVL. The sensitivity of family history was under 50%. 35% of cases compared with 8% of controls carried the FVL mutation. The most significant independent risk factors of thromboembolism were inherited FVL (odds ratio, 4.9) and acquired risk factors--i.e., surgery, leg fractures, distortions, confinement to bed for more than 1 week, or a restricted sitting position more than 6 hours in the 4 weeks before the index date (odds ratio, 10.1). Both heterozygote and homozygote FVL carriers did not suffer earlier from thromboembolism than patients without the mutation. These findings indicate that family history is not an effective predictor of FVL. However, even if the advantages of OC use are greater than the thrombotic risk, screening for FVL may be indicated to permit high-risk women to take preventive action.

An amplification-promoting sequence from mouse genomic DNA: interaction with a trans-acting factor that also affects gene expression.

We previously identified murine DNA sequences that stimulate the amplification of cis-linked plasmid DNA in mouse cells under selective conditions (Holst et al., 1988). Here we focus on the structural features of one of these elements, the 229-bp element 5. The amplification-promoting activity was fully recovered from the middle part of element 5. The active region interacted in a sequence-specific way with a protein from nuclear extracts. Using footprinting analyses the binding region was characterized and subsequently shown to be functionally active as an amplification-promoting sequence, whereas a mutated binding site was inactive. Therefore, cis-acting element 5 functioned via interaction with a trans-acting factor. The same binding site was also active as a promoter element for RNA polymerase II transcription, because it efficiently reconstituted the activity of a truncated herpes simplex virus type 1 (HSV-1) thymidine kinase (tk) gene promoter lacking the distal Sp1 binding site. Thus, the same protein seems to function in both RNA polymerase II transcription and DNA amplification. Possible relationships between both functions are discussed.

Genetic risk factors in young adults with 'cryptogenic' ischemic cerebrovascular disease.

Mutations such as factor V Leiden G1691A (FVL), prothrombin G20210A (FIIM), methylenetetrahydrofolate reductase (MTHFR) C677T, cystathionine beta-synthase (CBS) 844ins68 and endothelial cell protein C receptor (EPCR) 4031ins23 are risk factors for thromboembolism. To assess the role of these mutations in young adults with cerebral ischemia of otherwise undetermined etiology, 93 patients younger than 50 years old with thromboembolic strokes or transient ischemic attacks were studied. One hundred and eighty-six healthy age-matched and sex-matched blood donors served as controls. The FVL mutation was detected in 15/93 patients and 13/186 controls. After adjustment for smoking, arterial hypertension, and hyperlipidemia, the association of the FVL mutation with cerebral ischemia [odds ratio (OR), 3.19; 95% confidence interval (CI), 1.38-7.39] remained significant. One of 93 patients and 6/186 controls were carriers of FIIM (OR, 0.33; 95% CI, 0.04-2.75). We detected the MTHFR TT677 genotype in 9/93 patients and 26/186 controls (OR, 0.66; 95% CI, 0.30-1.47), a CBS 844ins68 mutation in 12/93 patients and 19/186 controls (OR, 1.30; 95% CI, 0.60-2.81), and an EPCR 4031ins23 mutation in 1/93 patients and in no control individual (P = 0.33). In conclusion, in younger adults the FVL mutation is a risk factor for cerebrovascular disease. FIIM, the MTHFR TT677 genotype and the CBS 844ins68 mutation did not contribute to the risk in this group of patients. The EPCR 4031ins23 mutation is very rare, its possible role needs further investigation.

The pathogenic role of virus-specific antibody-secreting cells in the central nervous system of rats with different susceptibility to coronavirus-induced demyelinating encephalitis.

The humoral immune response in the central nervous system (CNS) of susceptible Lewis (LE) rats and resistant Brown Norway (BN) rats was analysed after intracerebral infection with the murine coronavirus JHM (MHV4). The subclinical course of the infection in BN rats was characterized by an early rise of neutralizing antibodies in the cerebrospinal fluid (CSF) 7 days post-infection. At this time in LE rats, neutralizing antibodies were not detectable in the CSF and the animals developed neurological signs of infection. Subsequently, LE rats recovered from disease. This process was accompanied by increasing titres of virus-neutralizing antibodies. Within the CNS parenchyma of both rat strains, equivalent numbers of IgM-secreting cells were detected. However, in BN rats, virus-specific IgG secreting cells appeared earlier and in higher numbers. Moreover, based on the size of zones of antibody secreted by single cells in the Spot-ELISA assay, it appeared that cells from BN rats secreted IgG antibody of higher affinity. These data suggest that early maturation of antiviral antibody responses in the resistant BN rat probably restricts the spread of viral infection to small foci within the CNS, resulting in a subclinical level of primary demyelination. In contrast, the absence of neutralizing antibodies in the susceptible LE rats favours spread of the virus throughout the CNS, resulting finally in severe neurological disease.

Population dynamics of lymphocyte subsets in the central nervous system of rats with different susceptibility to coronavirus-induced demyelinating encephalitis.

The inflammatory response in the central nervous system (CNS) of rats with differing susceptibility to demyelinating encephalitis induced by coronavirus MHV4 was characterized. Topographical maps showing the arrangement of infiltrating lymphocyte subsets in virus-infected tissue were developed by digital-image processing of immunohistologically stained CNS sections. The kinetics of the inflammatory process was evaluated by flow-cytometry on lymphocytes isolated from the CNS. Cumulative data obtained with these two techniques demonstrated the following features. In susceptible Lewis (LE) rats, viral antigens were disseminated throughout the CNS, including spinal cord. Onset as well as recovery from neurological disease was associated with a steep rise of infiltrating CD8+ T cells, which localized in close contact to virus-infected cells. Accompanying convalescence was a slight increase in B(OX33+) cells in the CNS and the accumulation of immunoglobulin-containing cells in the centre of virus-infected areas. In clinically resistant Brown Norway (BN) rats, virus-infected cells were mainly restricted to small periventricular foci and the extent of lymphocyte infiltration was never as high as that found at any time during the course of infection in LE rats. There were striking differences in the CD8+ T-cell population compared to LE rats. Cells of this phenotype were identified in virus-affected areas of BN rats only early after infection, and their infiltration profile revealed much lower quantities than in the CNS of susceptible LE rats. Although the population dynamics of B(OX33+) lymphocytes were comparable in BN and LE rats, as determined by flow-cytometry, less immunoglobulin-containing B cells were detected in virus-infected areas of BN rats.

A comparative evaluation of the effect of pump type and heparin-coated surfaces on platelets during cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) is associated with hemostatic disorders, mainly due to platelet function defects. In the present prospective study, platelet count and GMP-140 expression on platelets were investigated to comparatively evaluate the impact of different CPB-circuit systems on platelets. The study included 61 patients undergoing coronary artery bypass grafting, randomly assigned to 3 groups. In group A a roller pump, in group B a centrifugal pump, and in group C a centrifugal pump with a Carmeda heparin-coated CPB circuit was applied. Platelet count and GMP-140 expression were analysed pre, during, and following CPB. None of the tested CPB systems did affect platelet count. The percentage of GMP-140-positive platelets increased slightly early during CPB, whereas it decreased significantly postoperatively; group differences were observed between B and C after protamin administration. An advantage of the use of centrifugal pumps and heparin-coated circuits could not be proven with the present set-up. The results suggest that the benefit of the tested systems might depend on the operative procedure and management.

Response of the cellular immune system to cardiopulmonary bypass is independent of the applied pump type and of the use of heparin-coated surfaces.

BACKGROUND: Cardiopulmonary bypass (CPB) is associated with an activation of leukocytes. The extent of this activation was thought to depend on the applied CPB-circuit set-up. The present study comparatively evaluated the effect of roller pump, centrifugal pump, and uncoated and heparin-coated surfaces. METHODS: 73 patients were included, randomly assigned to 3 groups. In group A a roller pump was used, in group B a centrifugal pump, and in group C a centrifugal pump together with Carmeda heparin-coated surfaces. The quantitative (cell count) and the qualitative changes of leukocyte populations (subpopulations and expression of the CD126-, HLA-DR-, CD45 RO-, CD71 antigens) was comparatively analysed before, during, and following CPB. RESULTS: Groups A and B did not differ in leukocyte counts and the differences between groups B and C were restricted to single time points. Neither groups A and B, nor groups B and C differed significantly in the relative distribution of lymphocyte subpopulations or in the percentage of CD126+, HLA-DR+, CD45 RO+ and CD71+ leukocyte subpopulations. CONCLUSIONS: CPB affects the cellular immune system; however, this effect seems to be a physiological reaction, independent of the applied CPB circuit system.

Recurrent optic nerve head infarctions associated with combined factor V Leiden- and factor II:G20210A-mutation.

PURPOSE: To demonstrate the association of bilateral recurrent optic nerve head infarctions with thrombophilia due to combined factor V:R506Q- and factor II:G20210A-mutation. METHODS: Case report. We examined a 55-year-old man with a two-year history of three segmental optic nerve head infarctions. Visual acuity was 20/80 on the left and 20/25 on the right eye. RESULTS: Ophthalmologic, cardiologic, radiologic, neurologic and hematologic-immunologic examinations were unremarkable except for increased APC-resistance (APC ratio: 1.4; normal value >2) due to heterozygous factor V:R506Q-mutation and high factor II-levels due to factor II:G20210A-mutation. Therapy with coumarin was instituted at INR 2.0-3.0 and no relapse has occurred over the past 1-year period. CONCLUSION: Combined occurrence of thrombogenic factor II:G20210A-mutation and factor V:R506Q-mutation may be causally linked to recurrent optic nerve head infarctions.