Symmetry- and gradient-enhanced Gaussian process regression for the active learning of potential energy surfaces in porous materials.

The theoretical investigation of gas adsorption, storage, separation, diffusion, and related transport processes in porous materials relies on a detailed knowledge of the potential energy surface of molecules in a stationary environment. In this article, a new algorithm is presented, specifically developed for gas transport phenomena, which allows for a highly cost-effective determination of molecular potential energy surfaces. It is based on a symmetry-enhanced version of Gaussian process regression with embedded gradient information and employs an active learning strategy to keep the number of single point evaluations as low as possible. The performance of the algorithm is tested for a selection of gas sieving scenarios on porous, N-functionalized graphene and for the intermolecular interaction of CH4 and N2.

Siplizumab selectively depletes effector memory T cells and promotes a relative expansion of alloreactive regulatory T cells in vitro.

Siplizumab, a humanized anti-CD2 monoclonal antibody, has been used in conditioning regimens for hematopoietic cell transplantation and tolerance induction with combined kidney-bone marrow transplantation. Siplizumab-based tolerance induction regimens deplete T cells globally while enriching regulatory T cells (Tregs) early posttransplantation. Siplizumab inhibits allogeneic mixed-lymphocyte reactions (MLRs) in vitro. We compared the impact of siplizumab on Tregs versus other T cell subsets in HLA-mismatched allogeneic MLRs using PBMCs. Siplizumab predominantly reduced the percentage of CD4+ and CD8+ effector memory T cells, which express higher CD2 levels than naïve T cells or resting Tregs. Conversely, siplizumab enriched proliferating CD45RA- FoxP3HI cells in MLRs. FoxP3 expression was stable over time in siplizumab-containing cultures, consistent with enrichment for bona fide Tregs. Consistently, high-throughput TCRß CDR3 sequencing of sorted unstimulated and proliferating T cells in MLRs revealed selective expansion of donor-reactive Tregs along with depletion of donor-reactive CD4+ effector/memory T cells in siplizumab-containing MLRs. These results indicate that siplizumab may have immunomodulatory functions that may contribute to its success in tolerance-inducing regimens. Our studies also confirm that naïve in addition to effector/memory T cells contribute to the allogeneic MLR and mandate further investigation of the impact of siplizumab on alloreactive naïve T cells.

Pharmacokinetic and pharmacodynamic study of a clinically effective anti-CD2 monoclonal antibody.

The humanized IgG1κ monoclonal antibody siplizumab and its rat parent monoclonal IgG2b antibody BTI-322 are directed against the CD2 antigen. Siplizumab is species-specific, reacting with human and chimpanzee cells but not with cells from any other species, including other non-human primates. Because siplizumab treatment has recently shown great potential in clinical transplantation, we now present the results of our previous pharmacokinetic, pharmacodynamic and safety studies of both antibodies. Fourteen chimpanzees received 1-3 doses of 0.143 to 5.0 mg/kg iv The effects were followed with flow cytometry on peripheral lymphocytes and staining of lymph nodes. Side effects were recorded. Serum antibody concentrations were followed. Across the doses, a rapid, transient depletion of CD2, CD3, CD4 and CD8 lymphocytes and NK cells was observed for both antibodies. Immune reconstitution was more rapid for BTI-322 compared to siplizumab. Paracortical lymph node T cell depletion was moderate, estimated at 45% with doses of >0.6 mg/kg. Restoration of lymph node architecture was seen after two weeks to two months for all animals. All four subjects receiving BTI-322 experienced AEs on the first dosing day, while the eight subjects dosed with siplizumab experienced few mild, transient AEs. Infusion with siplizumab and BTI-322 resulted in rapid depletion of CD2+ cells in circulation and tissue. Siplizumab had a longer t1/2 and fewer AEs compared to BTI-322.

Safety and pharmacodynamics of anti-CD2 monoclonal antibody treatment in cynomolgus macaques - an experimental study.

Anti-CD2 treatment provides targeted immunomodulatory properties that have demonstrated clinical usefulness to condition the immune system and to treat transplant rejection. The treatment is species-specific due to structural CD2 antigen differences between nonhuman primates and humans. Herein, we report the safety profile and efficacy of two modifications of the same anti-CD2 monoclonal antibody in cynomolgus macaques. Twelve subjects received one i.v. anti-CD2 (of rat or rhesus type) dose each, range 1-4 mg/kg, and were followed for 1-7 days. Treatment effects were evaluated with flow cytometry on peripheral blood and histopathological evaluation of secondary lymphoid organs. In vitro inhibitory activity on primary MHC disparate mixed lymphocyte reactions (MLRs) was determined. Upon anti-CD2 treatment, CD4+ , CD8+ memory subsets were substantially depleted. Naïve T cells and Tregs were relatively spared and exhibited lower CD2 expression than memory T cells. Early immune reconstitution was noted for naïve cells, while memory counts had not recovered after one week. Both antibodies displayed a concentration-dependent MLR inhibition. Lymph node examination revealed no significant lymphocyte depletion. None of the animals experienced any significant study drug-related adverse events. This study outlines the safety and pharmacodynamic profile of primate-specific anti-CD2 treatment, relevant for translation of anti-CD2-based animal models into clinical trials.

Siplizumab Induces NK Cell Fratricide Through Antibody-Dependent Cell-Mediated Cytotoxicity.

The glycoprotein CD2 is expressed on T and NK cells and contributes to cell-cell conjugation, agonistic signaling and actin cytoskeleton rearrangement. CD2 has previously been shown to have an important function in natural NK cell cytotoxicity but to be expendable in antibody-mediated cytotoxicity. Siplizumab is a monoclonal anti-CD2 IgG1 antibody that is currently undergoing clinical trials in the field of transplantation. This study investigated the effect of CD2 binding and Fc γ receptor binding by siplizumab (Fc-active) and Fc-silent anti-CD2 monoclonal antibodies in allogeneic mixed lymphocyte reaction and autologous lymphocyte culture. Further, induction of NK cell fratricide and inhibition of natural cytotoxicity as well as antibody-dependent cytotoxicity by these agents were assessed. Blockade of CD2 via monoclonal antibodies in the absence of Fc γ receptor binding inhibited NK cell activation in allogeneic mixed lymphocyte reaction. In contrast, siplizumab increased NK cell activation in both mixed lymphocyte reaction and autologous lymphocyte culture due to FcγRIIIA binding. However, experiments using purified NK cells did not show an inhibitory effect of CD2 blockade on natural cytotoxicity or antibody-dependent cytotoxicity. Lastly, it was shown that siplizumab induces NK cell fratricide. Concluding, siplizumab is a promising biopharmaceutical drug candidate for depletion of T and NK cells with minimal off-target effects.

[Intensive care treatment for neuroleptic malignant syndrome]. / Intensivmedizinisches Management des malignen neuroleptischen Syndroms. Literaturübersicht mit Fallbeispiel.

We report a case of severe neuroleptic malignant syndrome developing in a 28-year-old female patient following deliberate self-poisoning with atypical antipsychotic drugs and serotonin reuptake inhibitors. Because of an increasing loss of consciousness she was rapidly transferred to an Intensive Care Unit. Following this, she became progressively febrile associated with rhabdomyolysis and life-threatening organ dysfunctions. Due to fast diagnosis and immediate therapy the patient was treated successfully. This article describes etiology, pathophysiology and symptoms of neuroleptic malignant syndrome. In addition therapeutic options are discussed.

Polyvinyl Alcohol Carbazate as a Polymer-Based Antitumoral Agent.

Development of treatment resistance is a major concern during treatment of cancer, and there is an unmet need for therapeutic strategies with novel modes of action. Polyvinyl alcohol carbazate (PVAC) is a polymer compound with unique biological properties. Herein, we describe the antitumoral effects of PVAC. Three well-established cell lines GIST-T1, B16.F10, and A375 were used to determine the in vitro antitumoral effects of PVAC. Assessments included light microscopy, cell viability, cell cycle, and apoptosis assays. In vivo treatment safety and efficacy were characterized in one immunocompetent (B16.F10) mouse model and one athymic nude (MDA-MB-231) mouse model. Excised tumors were measured, weighed, stained for Ki-67, CD3, and histopathologically evaluated. Intact PVAC expressed a non-linear dose-response antitumoral effect in vitro, whereas its separate components, PVA and carbazate, did not display antitumoral effects alone. In vivo, PVAC induced a significant intratumoral CD3+ T-cell recruitment in immunocompetent mice (B16.F10), which was associated with tumor growth inhibition. Although growth inhibition was not significant in athymic mice (MDA-MB-231), histopathological evaluation detected an increase in stromal tissue and leukocyte infiltration. In conclusion, we present evidence for PVAC antitumoral effects both in vitro and in vivo. The mode of action was not elucidated in vitro, but a potential mechanism of in vivo activity was observed, characterized by an increase of immune cells into both immunocompetent and athymic mice. This finding warrants further study to validate its possible role as an immunomodulatory polymeric agent.

Siplizumab, an Anti-CD2 Monoclonal Antibody, Induces a Unique Set of Immune Modulatory Effects Compared to Alemtuzumab and Rabbit Anti-Thymocyte Globulin In Vitro.

Antibodies are commonly used in organ transplant induction therapy and to treat autoimmune disorders. The effects of some biologics on the human immune system remain incompletely characterized and a deeper understanding of their mechanisms of action may provide useful insights for their clinical application. The goal of this study was to contrast the mechanistic properties of siplizumab with Alemtuzumab and rabbit Anti-Thymocyte Globulin (rATG). Mechanistic assay systems investigating antibody-dependent cell-mediated cytotoxicity, antibody-dependent cell phagocytosis and complement-dependent cytotoxicity were used to characterize siplizumab. Further, functional effects of siplizumab, Alemuzumab, and rATG were investigated in allogeneic mixed lymphocyte reaction. Changes in T cell activation, T cell proliferation and frequency of naïve T cells, memory T cells and regulatory T cells induced by siplizumab, Alemtuzumab and rATG in allogeneic mixed lymphocyte reaction were assessed via flow cytometry. Siplizumab depleted T cells, decreased T cell activation, inhibited T cell proliferation and enriched naïve and bona fide regulatory T cells. Neither Alemtuzumab nor rATG induced the same combination of functional effects. The results presented in this study should be used for further in vitro and in vivo investigations that guide the clinical use of immune modulatory biologics.

CD2 Immunobiology.

The glycoprotein CD2 is a costimulatory receptor expressed mainly on T and NK cells that binds to LFA3, a cell surface protein expressed on e.g., antigen-presenting cells. CD2 has an important role in the formation and organization of the immunological synapse that is formed between T cells and antigen-presenting cells upon cell-cell conjugation and associated intracellular signaling. CD2 expression is upregulated on memory T cells as well as activated T cells and plays an important role in activation of memory T cells despite the coexistence of several other costimulatory pathways. Anti-CD2 monoclonal antibodies have been shown to induce immune modulatory effects in vitro and clinical studies have proven the safety and efficacy of CD2-targeting biologics. Investigators have highlighted that the lack of attention to the CD2/LFA3 costimulatory pathway is a missed opportunity. Overall, CD2 is an attractive target for monoclonal antibodies intended for treatment of pathologies characterized by undesired T cell activation and offers an avenue to more selectively target memory T cells while favoring immune regulation.

Immunization as treatment for Parkinson's disease.

Parkinson's disease and other neurodegenerative disorders share a common pathologic pathway with aggregation and deposition of misfolded proteins causing a disruption of particular neuronal networks. Several mechanisms have been implicated in the downstream events following deposition of misfolded proteins including free radical formation and failure of cellular defences such as autophagy or protein-degradation by the ubiquitin-proteasome pathway among many others. Treatments, however, capable of arresting or at least effectively modifying the course of disease do not yet exist. Recently, immunization approaches including passive and active immunization have been tested in animal models of various neurodegenerative disorders and have already entered into clinical trials for the treatment of Alzheimer's disease. In this review, we specifically focus on the current status of immune-based approaches that are presently developed as a potential therapy of Parkinson's disease.

Simulation of the hydrodynamic drag of aggregated particles.

The drag force on aggregates and partially sintered agglomerates is assessed using the lattice Boltzmann method (LBM) and accelerated Stokesian dynamics (ASD). Both methods have been compared in terms of accuracy and computational effort. It is shown that they give comparable results if all numerical parameters are controlled carefully. LBM requires a much higher computational effort, however, in contrast to ASD it is able to simulate partially sintered agglomerates as well. The results show that even a very small amount of sintering leads to a significant reduction in the drag force. The analysis of the drag force on agglomerates as well as on aggregates shows that there is no simple geometric quantity which is uniquely related to the drag force. Moreover, there is a significant variation in drag force for single aggregates at different orientations or for the orientation averaged drag force of different aggregates of the same size. This is explained by the structural effects which may lead to a variation in the drag force up to +/-20%.

The type III secretion system of biocontrol Pseudomonas fluorescens KD targets the phytopathogenic Chromista Pythium ultimum and promotes cucumber protection.

The type III secretion system (TTSS) is used by Proteobacteria for pathogenic or symbiotic interaction with plant and animal hosts. Recently, TTSS genes thought to originate from the phytopathogen Pseudomonas syringae were evidenced in Pseudomonas fluorescens KD, which protects cucumber from the oomycete Pythium ultimum (kingdom Chromista/Stramenopila). However, it is not known whether the TTSS contributes to plant protection by the bacterium and, if so, whether it targets the plant or the phytopathogen. Inactivation of TTSS gene hrcV following the insertion of an omega cassette strongly reduced the biocontrol activity of the pseudomonad against P. ultimum on cucumber when compared with the wild type, but had no effect on its root-colonization ability. Analysis of a plasmid-based transcriptional hrpJ'-inaZ reporter fusion revealed that expression in strain KD of the operon containing hrcV was strongly stimulated in vitro and in situ by the oomycete and not by the plant. In vitro, both strain KD and its hrcV mutant reduced the activity level of the pectinase polygalacturonase (a key pathogenicity factor) from P. ultimum, but the reduction was much stronger with the wild type. Together, these results show that the target range of bacterial TTSS is not restricted to plants and animals but also can include members of Chromista/Stramenopila, and suggest that virulence genes acquired horizontally from phytopathogenic bacteria were functionally recycled in biocontrol saprophytic Pseudomonas spp., resulting in enhanced plant protection by the latter.

Decreasing incidence of severe diabetic microangiopathy in type 1 diabetes.

OBJECTIVE: Conflicting evidence of a decline in incidence of microvascular complications in type 1 diabetes during the last decades has been reported. To assess recent trends in the cumulative incidence of diabetic microangiopathy in type 1 diabetes, we analyzed data from long-term prospective observational studies lasting >/=20 years. RESEARCH DESIGN AND METHODS: A total of 600 Caucasian patients with onset of type 1 diabetes between 1965 and 1984 were followed until death or until the year 2000. Patients were divided into four groups based on the year of diabetes onset: group A, 1965-1969 (n = 113); group B, 1970-1974 (n = 130); group C, 1975-1979 (n = 113); and group D, 1979-1984 (n = 244). Group A, B, and C are prevalence cohorts identified in 1984; group D is an inception cohort. RESULTS: In patients followed for >/=20 years, the cumulative incidence (95% CI) of diabetic nephropathy after 20 years of diabetes (urinary albumin excretion >300 mg/24 h) was reduced in patients with more recent diabetes onset (groups A-D): 31.1% (22.5-39.7) vs. 28.4% (19.8-37.0) vs. 18.9% (10.9-26.9) vs. 13.7% (6.2-21.2) (P = 0.015). Similarly, the cumulative incidence of proliferative retinopathy was as follows: 31.2% (22.2-39.8) vs. 30.3% (22.2-38.4) vs. 19.3% (11.2-27.4) vs. 12.5% (5.2-19.8) (P < 0.01). In the latter groups, antihypertensive treatment was started earlier, blood pressure and HbA(1c) were lower, and fewer patients smoked. CONCLUSIONS: Our study demonstrates a decrease in the cumulative incidence of diabetic microangiopathy in type 1 diabetes over the past 35 years. Improved glycemic control, lower blood pressure (in part due to early aggressive antihypertensive treatment), and reduced prevalence of smoking rates were associated with the improved prognosis.

Diabetes care may be improved with Steno Quality Assurance Tool--a self-assessment tool in diabetes management.

UNLABELLED: To evaluate if improvements in the quality of diabetes care in Indian clinics can be obtained by simple self-surveillance PC-based software. METHOD: Nineteen Indian diabetes clinics were introduced to the principles of quality assurance (QA), and to a software program, the Steno Quality Assurance Tool (SQAT). Data was entered for an initial 3 months period. Subsequently data were analyzed by the users, who designed plans to improve indicator status and set goals for the upcoming period. A second data entry period followed after 7-9 months. RESULTS: QA data was analyzed from 4487 T2DM patients (baseline) and 4440 (follow-up). The average examination frequency per clinic of the following indicators increased significantly: lipid examination (72-87%) (p=0.007), foot examination (80-94%) (p=0.02), HbA1c investigation (59-77%) (p=0.006), and urine albumin excretion investigation (72-87%) (p=0.006). Outcome parameters also improved significantly: mean (SD) fasting and post prandial BG reduced from 144(16) to 132(16)mg/dl (p=0.02) and 212(24)-195(29)mg/dl (p=0.03), respectively. Systolic BP reduced from 139(6) to 133(4) (p=0.0008)mmHg and diastolic BP from 83(3) to 81(3)mmHg (p=0.002). CONCLUSION: Quality of diabetes care can be improved by applying SQAT, a QA self-surveillance software that enables documentation of changes in process and outcome indicators.

Efficacy of vitamin E and N-acetylcysteine in the prevention of contrast induced kidney injury in patients with chronic kidney disease: a double blind, randomized controlled trial.

BACKGROUND: Contrast induced acute kidney injury is one of the most frequent causes of hospital acquired acute kidney injury. The present study aims to investigate the efficacy of vitamin E or N-acetylcysteine as an adjunct to current standard therapy in the prevention of this clinical predicament. We tested the hypothesis that vitamin E or N-acetylcysteine added to standard therapy with 0.45 % saline is superior in preserving renal function in patients with chronic kidney disease stage 1-4 undergoing elective computer-assisted tomography with nonionic radiocontrast agents when compared to 0.45 % saline alone. DESIGN: Prospective, randomized, single-center, double-masked, double dummy, placebo-controlled, parallel clinical trial. METHODS: The patients were randomized to either vitamin E (total dose 2160 mg i.v.) or N-acetylcysteine (total dose 4800 mg p.o.) in addition to 0.45 % saline (1 mL/kg/h over 24 h) or saline alone. Serum creatinine change between baseline and 24 h after radiocontrast was the primary outcome. Contrast induced acute kidney injury was defined as a rise in serum creatinine > 25 % over the baseline value within 48 h. RESULTS: Thirty patients (mean age 74.6 years; 17 females; 9 diabetics; all Caucasians; mean serum creatinine 1.35 mg/dL; mean creatinine clearance 56 mL/min) were enrolled. No patient developed contrast induced acute kidney injury. There was no significant difference in serum creatinine change between the three study arms. CONCLUSION: Following radiocontrast administration, neither vitamin E nor N-acetylcystein in addition to saline demonstrated an additional beneficial effect on kidney function when compared to saline alone.

Vibration-induced effects in stroke patients with spastic hemiparesis--a pilot study.

BACKGROUND: Spasticity manifesting as a dysbalance between extensor and flexor muscles may contribute to an impaired hand function. We studied clinical (n=10 patients) and electrophysiological (n=9 patients) changes produced by vibration of forearm extensor muscles (FEM) in chronic stroke patients with spastic hemiparesis. METHODS: In Exp. 1, the Box and Block Test (BBT) was applied to test dexterity before and after 5 minutes of FEM vibration. In Exp. 2, transcranial magnetic stimulation was used to study the cortical silent period (CSP) before and during FEM vibration. Recordings were taken from the antagonistic flexor carpi radialis muscle. RESULTS: After vibration, performance of the BBT was improved by 20%. The effect persisted for at least 10-15 minutes. Vibration induced a prolongation of the CSP. This effect occurred in the affected and non-affected side to a similar degree. The magnitude of performance changes and CSP changes was not correlated. CONCLUSIONS: FEM vibration enhances inhibitory neuronal circuits targeting the antagonistic forearm flexor muscles and is associated with an improved dexterity in the spastic arm. It might become a supporting tool in the motor recovery of spastic hemiparesis.

Structural dependent drag force and orientation prediction for small fractal aggregates.

Aggregates settle in viscous fluids in specific directions depending on their morphology. We investigated the settling behavior of fractal aggregates with D(f)=1.85 in fluids using the Accelerated Stokesian Dynamics method. The results have been compared with experimental data. A simple equation is proposed which gives the drag force in dependence on the radius of gyration r(gyr), the projection area A(p) and the aggregate orientation during settling. This equation reproduces the data from ASD within +/-10% for Re <1. Additionally, a new algorithm has been developed which allows a prediction of the orientation of such fractal aggregates provided that they have time enough to orient in the fluid. Moreover, the drag force acting on them can be predicted in a narrow range (maximum error 15%). This algorithm allows a very fast evaluation of the orienting behavior with small deviations.

Vibration prolongs the cortical silent period in an antagonistic muscle.

We tested whether the silent period, an indicator of inhibitory neuronal activity, is modulated by muscle vibration. Vibration was applied to the right extensor carpi radialis (ECR) muscle in 17 healthy subjects and, as a control experiment, to the dorsal terminal phalanges in 5 subjects. Data before vibration were compared with those during vibration. The cortical silent period (CSP) was evoked by transcranial magnetic stimuli (TMS) during voluntary wrist flexion or during voluntary wrist extension. TMS-evoked motor potentials (MEPs) of the flexor carpi radialis (FCR) muscle were recorded during muscle relaxation. The mixed nerve silent period (MNSP) was obtained by electrical stimulation of the median nerve during wrist flexion. ECR vibration induced a significant prolongation of the CSP in FCR. CSP increases induced by vibration of the dorsal terminal phalanges were significantly less pronounced. In ECR, the CSP tended to be shortened. MEPs and MNSP remained unchanged. We conclude that vibration enhances inhibitory neuronal properties in a non-vibrated antagonistic muscle, presumably at a supraspinal level. These results may be relevant for the treatment of spasticity of the upper extremity.

Predictors for the development of microalbuminuria and macroalbuminuria in patients with type 1 diabetes: inception cohort study.

OBJECTIVE: To evaluate baseline predictors for the development of persistent microalbuminuria and macroalbuminuria prospectively in patients with type 1 diabetes. DESIGN: Prospective observational study of an inception cohort. SETTING: Outpatient diabetic clinic in a tertiary referral centre, Gentofte, Denmark. PARTICIPANTS: 286 patients (216 adults) newly diagnosed with type 1 diabetes consecutively admitted to the clinic between 1 September 1979 and 31 August 1984. MAIN OUTCOME MEASURES: Persistent microalbuminuria and persistent macroalbuminuria. RESULTS: During the median follow up of 18.0 years (range 1.0-21.5 years), total of 4706 patient years of follow up, 79 of 277 (29%) patients developed persistent microalbuminuria. 27 of 79 progressed further to persistent macroalbuminuria. The cumulative incidence of persistent microalbuminuria and persistent macroalbuminuria was 33.6% (95% confidence interval 27.2% to 40.0%) and 14.6% (8.9% to 20.3%), respectively. Significant predictors for the development of persistent microalbuminuria were a 10-fold increase in urinary albumin excretion rate (relative risk 3.78, 1.57 to 9.13), being male (2.41, 1.43 to 4.06), a 10 mm Hg increase in mean arterial blood pressure (1.38, 1.20 to 1.57), a 1% increase in haemoglobin A1c (1.18, 1.04 to 1.32), and a 1 cm increase in height (0.96, 0.95 to 0.98). 28 patients with microalbuminuria (35%) regressed to normoalbuminuria either transiently (n = 15) or permanently (n = 13). CONCLUSIONS: Around one third of patients newly diagnosed with type 1 diabetes develop persistent microalbuminuria within the first 20 years of diabetes. Several potentially modifiable risk factors predict the development of persistent microalbuminaria and persistent macroalbuminuria.