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1.
J Prev Alzheimers Dis ; 11(2): 329-338, 2024.
Article in English | MEDLINE | ID: mdl-38374739

ABSTRACT

The Real-World Implementation, Deployment, and Validation of Early Detection Tools and Lifestyle Enhancement (AD-RIDDLE) project, recently launched with the support of the EU Innovative Health Initiative (IHI) public-private partnership and UK Research and Innovation (UKRI), aims to develop, test, and deploy a modular toolbox platform that can reduce existing barriers to the timely detection, and therapeutic approaches in Alzheimer's disease (AD), thus accelerating AD innovation. By focusing on health system and health worker practices, AD-RIDDLE seeks to improve and smooth AD management at and between each key step of the clinical pathway and across the disease continuum, from at-risk asymptomatic stages to early symptomatic ones. This includes innovation and improvement in AD awareness, risk reduction and prevention, detection, diagnosis, and intervention. The 24 partners in the AD-RIDDLE interdisciplinary consortium will develop and test the AD-RIDDLE toolbox platform and its components individually and in combination in six European countries. Expected results from this cross-sectoral research collaboration include tools for earlier detection and accurate diagnosis; validated, novel digital cognitive and blood-based biomarkers; and improved access to individualized preventative interventions (including multimodal interventions and symptomatic/disease-modifying therapies) across diverse populations, within the framework of precision medicine. Overall, AD-RIDDLE toolbox platform will advance management of AD, improving outcomes for patients and their families, and reducing costs.


Subject(s)
Alzheimer Disease , Humans , Alzheimer Disease/diagnosis , Alzheimer Disease/prevention & control , Biomarkers/metabolism , Early Diagnosis , Precision Medicine , Risk Reduction Behavior
2.
Clin Res Cardiol ; 112(11): 1639-1649, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37422840

ABSTRACT

BACKGROUND AND AIMS: Low-density lipoprotein cholesterol (LDL-C) is the main therapeutic target in the treatment of hypercholesterolemia. Small interfering RNA (siRNA) inclisiran is a new drug, which targets PCSK9 mRNA in the liver, reducing concentrations of circulating LDL-C. In randomized trials, inclisiran demonstrated a substantial reduction in LDL-C. The German Inclisiran Network (GIN) aims to evaluate LDL-C reductions in a real-world cohort of patients treated with inclisiran in Germany. METHODS: Patients who received inclisiran in 14 lipid clinics in Germany for elevated LDL-C levels between February 2021 and July 2022 were included in this analysis. We described baseline characteristics, individual LDL-C changes (%) and side effects in 153 patients 3 months (n = 153) and 9 months (n = 79) after inclisiran administration. RESULTS: Since all patients were referred to specialized lipid clinics, only one-third were on statin therapy due to statin intolerance. The median LDL-C reduction was 35.5% at 3 months and 26.5% at 9 months. In patients previously treated with PCSK9 antibody (PCSK9-mAb), LDL-C reductions were less effective than in PCSK9-mAb-naïve patients (23.6% vs. 41.1% at 3 months). Concomitant statin treatment was associated with more effective LDL-C lowering. There was a high interindividual variability in LDL-C changes from baseline. Altogether, inclisiran was well-tolerated, and side effects were rare (5.9%). CONCLUSION: In this real-world patient population referred to German lipid clinics for elevated LDL-C levels, inclisiran demonstrated a high interindividual variability in LDL-C reductions. Further research is warranted to elucidate reasons for the interindividual variability in drug efficacy.


Subject(s)
Anticholesteremic Agents , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Humans , Cholesterol, LDL , Proprotein Convertase 9 , Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects , RNA, Small Interfering/adverse effects , Anticholesteremic Agents/adverse effects
3.
Nat Commun ; 13(1): 2058, 2022 04 19.
Article in English | MEDLINE | ID: mdl-35440543

ABSTRACT

Extreme rainfall events in the humid-tropical Luquillo Mountains, Puerto Rico export the bulk of suspended sediment and particulate organic carbon. Using 25 years of river carbon and suspended sediment data, which targeted hurricanes and other large rainstorms, we estimated biogenic particulate organic carbon yields of 65 ± 16 tC km-2 yr-1 for the Icacos and 17.7 ± 5.1 tC km-2 yr-1 for the Mameyes rivers. These granitic and volcaniclastic catchments function as substantial atmospheric carbon-dioxide sinks, largely through export of river biogenic particulate organic carbon during extreme rainstorms. Compared to other regions, these high biogenic particulate organic carbon yields are accompanied by lower suspended sediment yields. Accordingly, particulate organic carbon export from these catchments is underpredicted by previous yield relationships, which are derived mainly from catchments with easily erodible sedimentary rocks. Therefore, rivers that drain petrogenic-carbon-poor bedrock require separate accounting to estimate their contributions to the geological carbon cycle.


Subject(s)
Carbon , Rivers , Carbon/analysis , Carbon Cycle , Environmental Monitoring , Forests , Puerto Rico
4.
PLoS One ; 15(7): e0235449, 2020.
Article in English | MEDLINE | ID: mdl-32716916

ABSTRACT

BACKGROUND: Several disease modifying drugs (DMDs) have been approved for the treatment of multiple sclerosis (MS), however, little is known about their differential impact on peripheral blood (PB) B cell subsets. METHODS: We performed a cross sectional study on PB B cells in MS patients treated with interferon-ß (n = 25), glatiramer acetate (n = 19), dimethyl fumarate (n = 15), fingolimod (n = 16) or natalizumab (n = 22), untreated MS patients (n = 20), and in patients with non-inflammatory neurological diseases (n = 12). Besides analyzing routine laboratory data, flow cytometry was performed to analyze naïve B cells (CD19+CD20+CD27-IgD+), non-class switched (CD19+CD20+CD27+IgD+) and class-switched memory B cells (CD19+CD20+CD27+IgD-), double negative B cells (CD19+CD20lowCD27-IgD-) and plasmablasts (CD19+CD20lowCD27+CD38++). RESULTS: Treatment associated changes were found for the overall B cell pool as well as for all B cell subsets. Natalizumab increased absolute numbers and percentage of all B cells mainly by expanding the memory B cell pool. Fingolimod decreased absolute numbers of all B cell subsets and the percentage of total B cells. Fingolimod, dimethyl fumarate and interferon-ß treatments were associated with an increase in the fraction of naïve B cells while class switched and non-class switched memory B cells showed decreased percentages. CONCLUSION: Our results highlight differential effects of DMDs on the PB B cell compartment. Across the examined treatments, a decreased percentage of memory B cells was found in dimethyl fumarate, interferon-ß and fingolimod treated patients which might contribute to the drugs' mode of action in MS. Further studies are necessary to decipher the exact role of B cell subsets during MS pathogenesis.


Subject(s)
B-Lymphocyte Subsets/drug effects , B-Lymphocytes/drug effects , Immunologic Memory/drug effects , Multiple Sclerosis/drug therapy , Adult , Aged , Aged, 80 and over , Antigens, CD/classification , Antigens, CD/immunology , Antigens, CD19 , B-Lymphocyte Subsets/classification , B-Lymphocyte Subsets/immunology , B-Lymphocytes/immunology , Cross-Sectional Studies , Dimethyl Fumarate/administration & dosage , Female , Fingolimod Hydrochloride/administration & dosage , Flow Cytometry , Glatiramer Acetate/administration & dosage , Humans , Immunologic Memory/immunology , Immunophenotyping , Immunosuppressive Agents/administration & dosage , Immunosuppressive Agents/immunology , Interferon-beta/administration & dosage , Male , Middle Aged , Multiple Sclerosis/blood , Multiple Sclerosis/immunology , Multiple Sclerosis/pathology , Natalizumab/administration & dosage , Young Adult
5.
Eur J Neurol ; 20(8): 1121-7, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23551588

ABSTRACT

Subarachnoid hemorrhage (SAH) is a devastating disease associated with death and poor functional outcome. Despite decades of intense research and improvements in clinical management, delayed cerebral ischaemia (DCI) remains the most important cause of morbidity and mortality after SAH. The key role of angiographic cerebral vasospasm, thought to be the main cause of DCI, has been questioned. Emerging evidence suggests that DCI is likely to have a multifactorial etiology. Over the last few years, spreading depolarization (SD) has been identified as a potential pathophysiological mechanism contributing to DCI. The presence of cortical spreading ischaemia, due to an inverse hemodynamic response to SD, offers a possible explanation for DCI and requires more intensive research. Understanding the role of SD as another mechanism inducing DCI and its relationship with other pathological factors could instigate the development of new approaches to the diagnosis and treatment of DCI in order to improve the clinical outcome.


Subject(s)
Cortical Spreading Depression/physiology , Subarachnoid Hemorrhage/physiopathology , Animals , Brain Ischemia/etiology , Brain Ischemia/physiopathology , Disease Models, Animal , Electroencephalography , Humans , Subarachnoid Hemorrhage/complications
6.
Bone Marrow Transplant ; 34(1): 85-7, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15156164

ABSTRACT

The use of VP-16 for stem cell mobilization has been cited as a significant risk factor for the development of therapy-related myelodysplasia/leukemia (tMDS/tAML) following autologous transplantation. The present study analyzed a large cohort of patients who underwent autotransplantation following stem cell mobilization with VP-16 and radiation-free preparation in order to determine the risk of tMDS/tAML. The estimated incidence of 9.9% at 7 years suggests that in the absence of TBI, VP-16 priming is not associated with an increased incidence of tMDS/tAML.


Subject(s)
Etoposide/toxicity , Leukemia/chemically induced , Neural Tube Defects/chemically induced , Peripheral Blood Stem Cell Transplantation/methods , Adolescent , Adult , Aged , Breast Neoplasms/complications , Breast Neoplasms/therapy , Etoposide/administration & dosage , Female , Hematopoietic Stem Cell Mobilization/adverse effects , Hematopoietic Stem Cell Mobilization/methods , Humans , Incidence , Lymphoma/complications , Lymphoma/therapy , Male , Middle Aged , Neoplasms, Second Primary/chemically induced , Peripheral Blood Stem Cell Transplantation/adverse effects , Probability , Transplantation, Autologous
7.
Bone Marrow Transplant ; 27(11): 1121-4, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11551021

ABSTRACT

Long-term outcome was analyzed in 28 patients transplanted between 1989 and 1992 following busulfan and cyclophosphamide and who had busulfan levels studied. While there was no significant correlation of busulfan levels with diagnosis, patients who had received extensive prior chemotherapy had a significantly higher area under the curve (AUC; P = 0.02) and maximum busulfan levels (Cmax; P = 0.03). High AUC was associated with the development of hepatic veno-occlusive disease (P = 0.03) and with early transplant-related mortality (P = 0.06). No significant correlation of busulfan levels with relapse, late non-relapse death, late complications, nor event-free survival was detected.


Subject(s)
Antineoplastic Agents, Alkylating/toxicity , Busulfan/toxicity , Hepatic Veno-Occlusive Disease/chemically induced , Adolescent , Adult , Antineoplastic Agents, Alkylating/blood , Antineoplastic Agents, Alkylating/pharmacokinetics , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Area Under Curve , Bone Marrow Transplantation/adverse effects , Bone Marrow Transplantation/mortality , Busulfan/blood , Busulfan/pharmacokinetics , Child , Child, Preschool , Cyclophosphamide/administration & dosage , Hematologic Neoplasms/complications , Hematologic Neoplasms/therapy , Humans , Longitudinal Studies , Transplantation Conditioning/adverse effects , Treatment Outcome
8.
IEEE Trans Biomed Eng ; 48(7): 838-42, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11442297

ABSTRACT

Microcontact printing (muCP) of extracellular matrix proteins is a fascinating approach to control cell positioning and outgrowth, which is essential in the development of applications ranging from cellular biosensors to tissue engineering. Microelectronic devices can be used to detect the activity from a large number of recording sites over the long term. However, signals from cells can only be recorded at small sensitive spots. In this paper, we present an innovative setup to perform aligned muCP of extracellular matrix proteins on microelectronic devices in order to guide the growth of electrogenic cells specifically to these sensitive spots. Our system is based on the combination of a fine-placer with redesigned micro stamps having a rigid glass cylinder as backbone for attachment in the alignment tool. Alignment is performed moving the device with an optical table under microscopic control of the superimposed images from stamp and device surface. After successful alignment, the stamp is brought into contact with the device surface by means of a high-precision lever. With our setup, we were able to pattern up to 40 devices per hour. A lateral alignment accuracy of < 2microm has been achieved. Aligned neuronal growth on patterned devices was demonstrated with dissociated hippocampal neurons.


Subject(s)
Microelectrodes , Neural Networks, Computer , Neurons/cytology , Animals , Cells, Cultured , Dimethylpolysiloxanes , Equipment Design , Extracellular Matrix , Hippocampus/cytology , Rats , Rats, Sprague-Dawley , Reproducibility of Results , Silicones , Surface Properties , Transistors, Electronic
10.
Ground Water ; 39(2): 192-202, 2001.
Article in English | MEDLINE | ID: mdl-11286066

ABSTRACT

More than 70 individual VOCs were identified in the leachate plume of a closed municipal landfill. Concentrations were low when compared with data published for other landfills, and total VOCs accounted for less than 0.1% of the total dissolved organic carbon. The VOC concentrations in the core of the anoxic leachate plume are variable, but in all cases they were found to be near or below detection limits within 200 m of the landfill. In contrast to the VOCs, the distributions of chloride ion, a conservative tracer, and nonvolatile dissolved organic carbon, indicate little dilution over the same distance. Thus, natural attenuation processes are effectively limiting migration of the VOC plume. The distribution of C2-3-benzenes, paired on the basis of their octanol-water partition coefficients and Henry's law constants, were systematically evaluated to assess the relative importance of volatilization, sorption, and biodegradation as attenuation mechanisms. Based on our data, biodegradation appears to be the process primarily responsible for the observed attenuation of VOCs at this site. We believe that the alkylbenzenes are powerful process probes that can and should be exploited in studies of natural attenuation in contaminated ground water systems.


Subject(s)
Organic Chemicals/analysis , Refuse Disposal , Soil Pollutants/analysis , Water Pollutants, Chemical/analysis , Biodegradation, Environmental , Chromatography, Gas , Hydrocarbons, Aromatic/analysis , Oklahoma , Volatilization , Water Movements
11.
Appl Opt ; 40(17): 2909-16, 2001 Jun 10.
Article in English | MEDLINE | ID: mdl-18357310

ABSTRACT

We derive a general, closed-form expression for the diffraction patterns including the aberrations that are due to off-axis alignment and positioning, of a paraboloid mirror. The diffraction patterns obtained in the focal plane of an off-axis paraboloidal mirror suffer modifications by the aberrations that are inherent in these surfaces: astigmatism and coma. Different magnifications in two perpendicular spatial directions indicate astigmatism. The Airy function, which affects a single spatial coordinate, describes the coma aberration. We identified the coma by the increased number of intensity zeros within adjacent lobules.

12.
Bone Marrow Transplant ; 26(10): 1037-43, 2000 Nov.
Article in English | MEDLINE | ID: mdl-11108300

ABSTRACT

Results in 164 patients who underwent allogeneic marrow transplantation following busulfan and cyclophosphamide over a 15 year period were analyzed. Age (median 37, range 14-66 years) did not significantly affect the incidence of graft-versus-host disease (GVHD), but patients who received methotrexate with cyclosporine had a significantly lower incidence (P = 0.002) of chronic GVHD compared to those who received methylprednisolone with cyclosporine. Hepatic veno-occlusive disease (VOD) occurred less frequently in chronic phase patients (P = 0.002) and in those transplanted shortly after diagnosis (P = 0.001). Five year leukemia-free survival (LFS) for the entire group was 49% (95% CI 41-57%). For 102 patients who underwent transplantation in chronic phase, results were significantly improved by transplantation at a short interval following diagnosis, particularly within 3 months (P = 0.01), by the use of methotrexate and not corticosteroids for GVHD prevention (P = 0.03), and by use of HLA-identical sibling donors (P = 0.01). Age was not a significant adverse prognostic factor and transplantation was successfully performed in individuals up to age 66. Allogeneic transplantation in CML, including older patients and those with unrelated donors, can be most safely and effectively performed shortly after diagnosis.


Subject(s)
Bone Marrow Transplantation , Busulfan/administration & dosage , Cyclophosphamide/administration & dosage , Graft vs Host Disease/prevention & control , Leukemia, Myeloid, Acute/therapy , Adolescent , Adult , Age Factors , Aged , Bone Marrow Transplantation/adverse effects , Cause of Death , Female , Fusion Proteins, bcr-abl/analysis , Hepatic Veno-Occlusive Disease/etiology , Humans , Male , Middle Aged , Recurrence , Transplantation, Homologous
13.
Brain Inj ; 14(10): 859-75, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11076133

ABSTRACT

The behavioural and cognitive sequelae of traumatic brain injury (TBI) have features in common with attention deficit/hyperactivity disorder (ADHD), best characterized by deficits in response inhibition.The performance was, therefore, examined of 27 children with TBI, 31 children with developmental ADHD, and 26 matched controls aged 8-12, on two inhibition tasks: the Stop-Signal Task and a Delayed-Response-Task. Children with TBI and children with ADHD showed a pervasive deficit in their inhibitory control processes with respect to inhibition of both pre-potent and on-going responses. In addition, children with TBI were found to suffer from a general slowing of their information processing, which was not correlated with the inhibition deficit. TBI children with and without a secondary ADHD differed only tendentially in their Mean Go-Reaction time in the stop-task. However, subdividing TBI children according to actigraph data into hypo-, hyper- and normokinetic subgroups revealed that the hyperactive TBI children had inhibitory deficit patterns that were similar to children with developmental ADHD. It is concluded that slowing of information processing speed seems to be a general consequence of TBI in childhood, whereas slowing of the stop-processes or inhibitory deficits, specifically, are associated with post-injury hypo- or hyperactivity.


Subject(s)
Attention Deficit Disorder with Hyperactivity/psychology , Brain Injuries/psychology , Inhibition, Psychological , Case-Control Studies , Child , Female , Humans , Male , Mental Processes , Reaction Time
15.
Arch Tierernahr ; 53(1): 59-73, 2000.
Article in English | MEDLINE | ID: mdl-10836258

ABSTRACT

The effects of (1-->3),(1-->6)-beta-D-glucan from Saccharomyces cerevisiae and of the fluochinolone enrofloxacin were studied on red and white blood cells and plasma proteins of growing chickens up to the 35th day of life. The prominent findings within the leukocyte population on a per cent scale are: (i) increase of leukocyte count; increase of neutrophils and decrease of lymphocytes in the control and in the antibiotic group from day 17 to day 35; (ii) a minor decrease of neutrophils and no change of lymphocytes in the glucan group; (iii) the monocytes increase from 2.5 +/- 1.8% to 6.5 +/- 7.6% in the glucan group; (iv) the basophils increase in the control group and scale down in the other groups from day 17 to day 35. The total count of leukocytes increases in the controls and in the glucan group. The total protein content of blood plasma, beta-globulin and gamma-globulin increase and the albumin-globulin-ratio and alpha-globulin decline during chickens growth. These changes are most prominent in the glucan group. The haemoglobin concentration shows in all three dietary groups a highly significant increase from day 17 to day 35 by about 17 to 27 per cent; no changes are seen in packed cell volume and number of erythrocytes per litre blood.


Subject(s)
Anti-Infective Agents/pharmacology , Blood Cells/drug effects , Blood Proteins/analysis , Chickens/blood , Fluoroquinolones , Glucans/pharmacology , Quinolones/pharmacology , Animals , Anti-Infective Agents/administration & dosage , Blood Cells/chemistry , Blood Cells/cytology , Blood Proteins/drug effects , Chickens/growth & development , Chickens/physiology , Enrofloxacin , Erythrocyte Count/veterinary , Glucans/administration & dosage , Hematocrit/veterinary , Hemoglobins/analysis , Leukocyte Count/veterinary , Lymphocyte Subsets/drug effects , Quinolones/administration & dosage , Serum Albumin/analysis , Serum Globulins/analysis
16.
Bone Marrow Transplant ; 25(12): 1219-22, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10871724

ABSTRACT

Prognostic factors in 42 patients aged 11 to 62 (median 46) years, with myelodysplastic syndrome (MDS) or after leukemic transformation, who underwent allogeneic marrow transplantation between 1984 and 1999 were analyzed. Thirty-six had advanced disease morphology; 19 had leukemic transformation. Twenty-nine received a preparative regimen of BuCy2 and 13 busulfan 14 mg/kg, etoposide 50 mg/kg and cyclophosphamide 120 mg/kg. Severe hepatic veno-occlusive disease (VOD) occurred in three patients all of whom received anti-leukemic chemotherapy prior to transplantation. Fifteen patients (36%) died from early transplant-related complications; nine patients relapsed. The estimated 4 year disease-free survival (DFS) was 35% (95% CI 26-44%). Older age was the most significant adverse prognostic factor. Patients with leukemic transformation who underwent early transplantation had significantly better DFS than those treated first with chemotherapy (P = 0.002). Delayed toxicity was rare in these patients; no late relapses occurred. Bone Marrow Transplantation (2000) 25, 1219-1222.


Subject(s)
Antineoplastic Agents, Alkylating/administration & dosage , Bone Marrow Transplantation , Busulfan/administration & dosage , Cyclophosphamide/administration & dosage , Immunosuppressive Agents/administration & dosage , Leukemia/therapy , Myelodysplastic Syndromes/therapy , Adult , Child , Combined Modality Therapy , Humans , Leukemia/physiopathology , Middle Aged , Myelodysplastic Syndromes/physiopathology , Prognosis , Transplantation, Homologous
17.
Bone Marrow Transplant ; 25(12): 1243-8, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10871728

ABSTRACT

The purpose of the study was to determine the toxicities and effectiveness of a novel preparative regimen of busulfan (Bu) 14 mg/kg, etoposide 50 or 60 mg/kg, and cyclophosphamide (Cy) 120 mg/kg in non-Hodgkin's lymphoma (NHL) and to analyze results using doses based on different body weight parameters and the two different etoposide doses. Three hundred and eighty-two patients aged 16 to 72 underwent first autologous transplantation with mobilized peripheral blood progenitor cells between August 1992 and December 1998 at either of two transplant centers. Mucositis was the most common toxicity. Hepatic toxicity was the most common life-threatening toxicity; severe hepatic VOD occurred in 11 patients (2.9%). Ten patients (2.6%) died from treatment-related toxicity. The 3-year progression-free survival (PFS) for the entire group was 46.9% (95% CI, 40.5-53.3%). Elevated LDH, resistance to chemotherapy, and intermediate/aggressive histology were significant adverse prognostic factors. For patients in sensitive first relapse PFS was 47.0% (95% CI, 37-57%). Neither etoposide dose nor body weight parameter utilized significantly affected outcome. In conclusion, the novel preparative regimen of Bu, etoposide and Cy results in a low incidence of treatment-related mortality and is effective in the treatment of patients with NHL. Bone Marrow Transplantation (2000) 25, 1243-1248.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Hematopoietic Stem Cell Transplantation , Lymphoma, Non-Hodgkin/therapy , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Busulfan/administration & dosage , Busulfan/adverse effects , Combined Modality Therapy , Cyclophosphamide/administration & dosage , Cyclophosphamide/adverse effects , Etoposide/administration & dosage , Etoposide/adverse effects , Humans , Lymphoma, Non-Hodgkin/pathology , Survival Analysis , Transplantation, Autologous
18.
J Neurosci Methods ; 104(1): 65-75, 2000 Dec 15.
Article in English | MEDLINE | ID: mdl-11163412

ABSTRACT

The control of neuronal cell position and outgrowth is of fundamental interest in the development of applications ranging from cellular biosensors to tissue engineering. We have produced rectangular networks of functional rat hippocampal neurons on silicon oxide surfaces. Attachment and network formation of neurons was guided by a geometrical grid pattern of the adhesion peptide PA22-2 which matches in sequence a part of the A-chain of laminin. PA22-2 was applied by contact printing onto the functionalised silicon oxide surface and was immobilised by hetero-bifunctional cross-linking with sulfo-GMBS. Geometric pattern matching was achieved by microcontact printing using a polydimethylsiloxane (PDMS) stamp. In this way the produced grid pattern ranged from 3 to 20 microm in line width and from 50 to 100 microm in line distances. As shown by atomic force microscopy (AFM), line widths and line distances of the peptide pattern differ less than 0.5 microm from the used PDMS stamp. The height of the layer of immobilised PA22-2 was approximately 3.5 nm implying the layer to be monomolecular. Immobilised PA22-2 was capable of binding anti-PA22-2 antibodies indicating that the function of the peptide was not compromised by immobilisation. Rat hippocampal neurons, cultured at low density in serum-free medium, were applied to the growth matrix of PA22-2-coated substrates and, within 1-3 h of culture, formed a network-like pattern that more or less matched the printed grid. Reliability and reproducibility of neuronal network formation depended on the geometry, line width and node diameter of the grid pattern. The immobilised neurons showed resting membrane potentials comparable with controls and, already after 1 day of culture, were capable of eliciting action potentials. The suitability of the immobilised neurons for the study of man-made neural networks and for multi-site recordings from a functional neuronal network is discussed.


Subject(s)
Cell Adhesion/drug effects , Cell Culture Techniques/methods , Electrophysiology/methods , Hippocampus/physiology , Nerve Net/physiology , Neurons/physiology , Oxides/pharmacology , Silicon Compounds/pharmacology , Animals , Biosensing Techniques/instrumentation , Biosensing Techniques/methods , Cell Adhesion/physiology , Cell Culture Techniques/instrumentation , Cell Size/drug effects , Cell Size/physiology , Cells, Cultured/drug effects , Cells, Cultured/physiology , Electrophysiology/instrumentation , Fetus , Hippocampus/cytology , Membrane Potentials/drug effects , Membrane Potentials/physiology , Nerve Net/cytology , Nerve Net/drug effects , Neurons/cytology , Neurons/drug effects , Peptides/pharmacology , Rats
19.
Child Neuropsychol ; 6(4): 286-96, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11992192

ABSTRACT

Recent research has demonstrated that both brain-injured children and children with attention deficit/hyperactivity disorder (ADHD) suffer from response inhibition deficits. To investigate whether these deficits can be influenced by motivational factors, the stop-signal task was performed with and without reward contingencies for successful inhibition. Three groups of children between 8 and 12 years of age, participated in the study: 31 children with ADHD, 37 with traumatic brain injuries (TBI), and 26 normal controls. Results indicated that, although all groups showed comparable learning effects, reward contingencies had different effects on the groups. Whereas the performance of children with ADHD under reward contingencies were brought up to the performance level of normal controls, rewards were found less effective at improving response inhibition in children with TBI. The results further support a motivational/energetic explanation of the inhibitory deficit in children with ADHD, and of a primary response inhibition deficit due to structural brain damage in children with TBI.


Subject(s)
Attention Deficit Disorder with Hyperactivity/psychology , Brain Injuries/psychology , Inhibition, Psychological , Motivation , Analysis of Variance , Attention Deficit Disorder with Hyperactivity/physiopathology , Child , Female , Humans , Male , Reaction Time/physiology , Reward
20.
In Vitro Cell Dev Biol Anim ; 35(6): 352-6, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10476923

ABSTRACT

Cardiac myocytes cultured over microfabricated extracellular recording devices can be used to assay bioactive compounds. However, electrophysiological signals recorded from these devices vary in amplitude with time. Theoretically, changes in signal amplitude arise from myocytes being moved over recording sites by cocultured fibroblasts. To test this, neonatal rat cardiac myocytes were cultured at high densities and low densities on fibronectin-coated glass. After 36.5 h, myocytes were identified by their rhythmic contractions and then time-lapse-recorded for 3.5 h. Length, width, and angle of orientation was then determined every 30 min for five cells in low density and five cells in high-density culture. Low-density cells had mean lengths of 65.3 microm and widths of 35.1 microm, whereas cells in high-density culture had greater mean lengths of 74.2 microm and lower mean widths of 24.3 microm. Length, width, and angle of orientation of cells in low- and high-density culture changed by 4.1%, 11.8%, and 2.7 degrees, and 6.4%, 10%, and 4.6 degrees, respectively, every half hour. We found no evidence of myocyte-fibroblast interactions influencing cell position or shape in low density, but in high density, we found evidence that fibroblast-myocyte interactions could transiently influence cell shape. We conclude that fibroblast-independent changes in cell shape are largely responsible for the changes in signal amplitude recorded from cardiac myocytes cultured on microfabricated extracellular recording devices. However, there is some evidence that myocyte-fibroblast interactions may augment this process in high-density culture. The implications of these findings for bioassay development are discussed.


Subject(s)
Cell Movement , Myocardium/cytology , Animals , Biological Assay , Cells, Cultured , Coculture Techniques , Fibroblasts/cytology , Fibroblasts/physiology , Rats , Rats, Sprague-Dawley
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