RESUMO
Subtle cognitive changes in preclinical Alzheimer's disease (AD) are difficult to detect using traditional pen-and-paper neuropsychological assessments. Remote and unsupervised digital assessments can improve scalability, measurement reliability, and ecological validity, enabling the detection and monitoring of subtle cognitive change. Here, we evaluate such tools deployed in preclinical AD samples, defined as cognitively unimpaired individuals with abnormal levels of amyloid-ß (Aß), or Aß and tau. In this scoping review, we screened 1,680 unique reports for studies using remote and unsupervised cognitive assessment tools in preclinical AD samples; 23 tools were found. We describe each tool's usability, validity, and reported metrics of reliability. Construct and criterion validity according to associations with established neuropsychological assessments and measures of Aß and tau are reported. With this review, we aim to present a necessary update to a rapidly evolving field, following a previous review by Öhman and colleagues (2021; Alzheimers Dement. Diagn. Assess. Dis. Monit) and addressing the open questions of feasibility and reliability of remote testing in the target population. We discuss future directions for using remote and unsupervised digital cognitive assessments in preclinical AD and how such tools may be used for longitudinal monitoring of cognitive function, scalable case finding, and individualized prognostics in both clinical trials and healthcare contexts.
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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.
Assuntos
Doença de Alzheimer , Humanos , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/prevenção & controle , Biomarcadores/metabolismo , Diagnóstico Precoce , Medicina de Precisão , Comportamento de Redução do RiscoRESUMO
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.
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Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Hemorragia Subaracnóidea/fisiopatologia , Animais , Isquemia Encefálica/etiologia , Isquemia Encefálica/fisiopatologia , Modelos Animais de Doenças , Eletroencefalografia , Humanos , Hemorragia Subaracnóidea/complicaçõesRESUMO
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.
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Anticolesterolemiantes , Inibidores de Hidroximetilglutaril-CoA Redutases , Humanos , LDL-Colesterol , Pró-Proteína Convertase 9 , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , RNA Interferente Pequeno/efeitos adversos , Anticolesterolemiantes/efeitos adversosRESUMO
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.
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Carbono , Rios , Carbono/análise , Ciclo do Carbono , Monitoramento Ambiental , Florestas , Porto RicoRESUMO
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.
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Subpopulações de Linfócitos B/efeitos dos fármacos , Linfócitos B/efeitos dos fármacos , Memória Imunológica/efeitos dos fármacos , Esclerose Múltipla/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos CD/classificação , Antígenos CD/imunologia , Antígenos CD19 , Subpopulações de Linfócitos B/classificação , Subpopulações de Linfócitos B/imunologia , Linfócitos B/imunologia , Estudos Transversais , Fumarato de Dimetilo/administração & dosagem , Feminino , Cloridrato de Fingolimode/administração & dosagem , Citometria de Fluxo , Acetato de Glatiramer/administração & dosagem , Humanos , Memória Imunológica/imunologia , Imunofenotipagem , Imunossupressores/administração & dosagem , Imunossupressores/imunologia , Interferon beta/administração & dosagem , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/sangue , Esclerose Múltipla/imunologia , Esclerose Múltipla/patologia , Natalizumab/administração & dosagem , Adulto JovemRESUMO
PURPOSE: We analyzed the safety and effectiveness of high-dose etoposide (2 g/m2) followed by granulocyte colony-stimulating factor (G-CSF) as a peripheral-blood progenitor cell (PBPC) mobilization regimen and assessed extent of tumor reduction in patients with breast cancer, non-Hodgkin's lymphoma (NHL), and Hodgkin's disease (HD). PATIENTS AND METHODS: One hundred sixty-nine consecutive patients who eventually underwent PBPC transplantation received treatment with high-dose etoposide (2 g/m2) followed by daily G-CSF (5 microg/kg). RESULTS: This mobilization method was effective in nearly all patients. No patients died of mobilization-related complications. A 50% reduction in tumor size was seen in 19% of assessable patients with breast cancer, 44% of those with NHL, and 38% of those with HD. Hematopoietic recovery (HR) following transplantation occurred in all patients. Patients with > or = 4 x 10(6) CD34+ cells/kg engrafted with neutrophils at a median of 9 days after transplant and patients with at least 1.2 x 10(6) CD34+/CD33- cells/kg achieved platelet recovery at a median of 15 days. CONCLUSION: Etoposide plus G-CSF is an effective and safe method for mobilization of PBPCs. Etoposide is an effective agent in tumor reduction in NHL and HD and is less effective in breast cancer. The substantially lower incidence of prior exposure to this agent compared with cyclophosphamide favors its use.
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Antineoplásicos Fitogênicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Etoposídeo/uso terapêutico , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Células-Tronco Hematopoéticas/efeitos dos fármacos , Doença de Hodgkin/tratamento farmacológico , Linfoma não Hodgkin/tratamento farmacológico , Adolescente , Adulto , Idoso , Antineoplásicos Fitogênicos/administração & dosagem , Coleta de Amostras Sanguíneas , Neoplasias da Mama/terapia , Criopreservação , Etoposídeo/administração & dosagem , Feminino , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Transplante de Células-Tronco Hematopoéticas , Doença de Hodgkin/terapia , Humanos , Imunofenotipagem , Linfoma não Hodgkin/terapia , Masculino , Pessoa de Meia-IdadeRESUMO
Two major problems of unrelated donor transplantation have been an increased incidence of GVHD and graft failure. Even with HLA identity by microlymphocytotoxicity assay and non-reactive MLC, URD marrow transplant recipients have a higher incidence of graft rejection and GVHD. The preparative regimen busulfan 16 mg/kg and cyclophosphamide 120 mg/kg (BuCy2) has been shown to be at least as effective in preparation of recipients with CML of HLA-identical sibling grafts as cyclophosphamide and total body irradiation (Cy/TBI). However, concern about a high rejection rate in URD transplants has prevented most centers from using BuCy2 in this setting. From March 1990 to March 1994, 26 patients underwent URD transplantation following preparation with BuCy2. Patients received either standard cyclosporine and methotrexate or cyclosporine and methylprednisolone for GVHD prophylaxis. Two patients died on day 16 and 20 without evidence of hematopoietic engraftment. Of the 24 patients evaluable for engraftment, 23 (96%) had evidence of donor engraftment defined as an ANC > 0.5 x 10(9)/1. No patient who had initial engraftment had late graft failure. Within our study group the risk of graft rejection or graft failure does not appear to be higher than that reported for URD transplants utilizing TBI-containing regimens.
Assuntos
Transplante de Medula Óssea , Bussulfano , Ciclofosfamida , Rejeição de Enxerto/epidemiologia , Leucemia/terapia , Síndromes Mielodisplásicas/terapia , Doadores de Tecidos , Condicionamento Pré-Transplante/métodos , Doença Aguda , Adolescente , Adulto , Transplante de Medula Óssea/efeitos adversos , Transplante de Medula Óssea/estatística & dados numéricos , Criança , Pré-Escolar , Quimera , Evolução Fatal , Feminino , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto , Doença Enxerto-Hospedeiro/epidemiologia , Doença Enxerto-Hospedeiro/prevenção & controle , Histocompatibilidade , Humanos , Imunossupressores/uso terapêutico , Incidência , Leucemia Mielogênica Crônica BCR-ABL Positiva/terapia , Contagem de Leucócitos , Tábuas de Vida , Masculino , Pessoa de Meia-Idade , Núcleo Familiar , Transplante Homólogo , Resultado do TratamentoRESUMO
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.
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Antineoplásicos Alquilantes/administração & dosagem , Transplante de Medula Óssea , Bussulfano/administração & dosagem , Ciclofosfamida/administração & dosagem , Imunossupressores/administração & dosagem , Leucemia/terapia , Síndromes Mielodisplásicas/terapia , Adulto , Criança , Terapia Combinada , Humanos , Leucemia/fisiopatologia , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/fisiopatologia , Prognóstico , Transplante HomólogoRESUMO
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.
Assuntos
Antineoplásicos Alquilantes/toxicidade , Bussulfano/toxicidade , Hepatopatia Veno-Oclusiva/induzido quimicamente , Adolescente , Adulto , Antineoplásicos Alquilantes/sangue , Antineoplásicos Alquilantes/farmacocinética , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Área Sob a Curva , Transplante de Medula Óssea/efeitos adversos , Transplante de Medula Óssea/mortalidade , Bussulfano/sangue , Bussulfano/farmacocinética , Criança , Pré-Escolar , Ciclofosfamida/administração & dosagem , Neoplasias Hematológicas/complicações , Neoplasias Hematológicas/terapia , Humanos , Estudos Longitudinais , Condicionamento Pré-Transplante/efeitos adversos , Resultado do TratamentoRESUMO
Between March 1984 and March 1995, 76 patients with advanced acute myelogenous, acute lymphoblastic, or chronic myelogenous leukemia underwent allogeneic marrow transplantation from HLA-identical or one-antigen mismatched sibling or unrelated donors. Patients received a preparative regimen consisting of busulfan 16 mg/kg and cyclophosphamide 120 mg/kg or busulfan 14 mg/kg, cyclophosphamide 120 mg/kg and etoposide (VP-16) 50 mg/kg. For GVHD prevention, patients received cyclosporine with either methotrexate or steroids or FK506 with methotrexate. Fourteen patients were leukemia-free survivors at a median of 6.5 years (range 1-11 years) following transplantation. For the group as a whole, the estimated leukemia-free survival (LFS) at 5 years is 20% (95% confidence interval 10-30%). Ten of the 14 leukemia-free survivors developed acute GVHD greater than grade II and chronic GVHD and two developed only chronic GVHD. Significantly better relapse rates and disease-free survival were associated with the development of acute and/or chronic GVHD. In the absence of acute GVHD and/or chronic GVHD, patients who underwent transplantation for advanced leukemia, after preparation with Bu/CY or Bu/CY/VP-16, were very likely to experience disease recurrence. Novel strategies designed to promote development of GVHD present a promising area for investigation to improve outcome in patients with leukemia at high risk for relapse.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Transplante de Medula Óssea , Doença Enxerto-Hospedeiro , Leucemia/terapia , Transplante de Medula Óssea/efeitos adversos , Bussulfano/administração & dosagem , Terapia Combinada , Ciclofosfamida/administração & dosagem , Etoposídeo/administração & dosagem , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/fisiopatologia , Humanos , Leucemia/mortalidade , Leucemia/fisiopatologia , Resultado do TratamentoRESUMO
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.
Assuntos
Transplante de Medula Óssea , Bussulfano/administração & dosagem , Ciclofosfamida/administração & dosagem , Doença Enxerto-Hospedeiro/prevenção & controle , Leucemia Mieloide Aguda/terapia , Adolescente , Adulto , Fatores Etários , Idoso , Transplante de Medula Óssea/efeitos adversos , Causas de Morte , Feminino , Proteínas de Fusão bcr-abl/análise , Hepatopatia Veno-Oclusiva/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Transplante HomólogoRESUMO
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.
Assuntos
Etoposídeo/toxicidade , Leucemia/induzido quimicamente , Defeitos do Tubo Neural/induzido quimicamente , Transplante de Células-Tronco de Sangue Periférico/métodos , Adolescente , Adulto , Idoso , Neoplasias da Mama/complicações , Neoplasias da Mama/terapia , Etoposídeo/administração & dosagem , Feminino , Mobilização de Células-Tronco Hematopoéticas/efeitos adversos , Mobilização de Células-Tronco Hematopoéticas/métodos , Humanos , Incidência , Linfoma/complicações , Linfoma/terapia , Masculino , Pessoa de Meia-Idade , Segunda Neoplasia Primária/induzido quimicamente , Transplante de Células-Tronco de Sangue Periférico/efeitos adversos , Probabilidade , Transplante AutólogoRESUMO
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.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Transplante de Células-Tronco Hematopoéticas , Linfoma não Hodgkin/terapia , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Bussulfano/administração & dosagem , Bussulfano/efeitos adversos , Terapia Combinada , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Etoposídeo/administração & dosagem , Etoposídeo/efeitos adversos , Humanos , Linfoma não Hodgkin/patologia , Análise de Sobrevida , Transplante AutólogoRESUMO
[formula: see text] A new family of 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene-substituted ruthenium-based complexes 9a-c has been prepared starting from RuCl2(=CHPh)(PCy3)2 2. These air- and water-tolerant complexes were shown to exhibit an increased ring-closing metathesis activity at elevated temperature when compared to that of the parent complex 2 and the previously developed complex 3. In many instances the activity of these complexes also rivaled or exceeded that of the alkoxy-imido molybdenum complex 1. Catalyst loadings of as low as 0.05 mol% could be used.
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Alcenos/química , Imidazóis/química , Rutênio/química , Catálise , LigantesRESUMO
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.
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Adesão Celular/efeitos dos fármacos , Técnicas de Cultura de Células/métodos , Eletrofisiologia/métodos , Hipocampo/fisiologia , Rede Nervosa/fisiologia , Neurônios/fisiologia , Óxidos/farmacologia , Compostos de Silício/farmacologia , Animais , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Adesão Celular/fisiologia , Técnicas de Cultura de Células/instrumentação , Tamanho Celular/efeitos dos fármacos , Tamanho Celular/fisiologia , Células Cultivadas/efeitos dos fármacos , Células Cultivadas/fisiologia , Eletrofisiologia/instrumentação , Feto , Hipocampo/citologia , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Rede Nervosa/citologia , Rede Nervosa/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Peptídeos/farmacologia , RatosRESUMO
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.
Assuntos
Microeletrodos , Redes Neurais de Computação , Neurônios/citologia , Animais , Células Cultivadas , Dimetilpolisiloxanos , Desenho de Equipamento , Matriz Extracelular , Hipocampo/citologia , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Silicones , Propriedades de Superfície , Transistores EletrônicosRESUMO
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.
Assuntos
Movimento Celular , Miocárdio/citologia , Animais , Bioensaio , Células Cultivadas , Técnicas de Cocultura , Fibroblastos/citologia , Fibroblastos/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
This research investigated the relation between children's performance on two measures of receptive language and children's auditory discrimination of consonant-vowel sounds having frequency and temporal acoustic differences. The measures of fine-grained auditory discrimination produced significant multiple regression coefficients against both receptive vocabulary (Peabody Picture Vocabulary Test-Revised) and receptive language (Token Test for Children) scores. Validation analyses conducted by predicting receptive vocabulary and language scores for a new sample of children and relating them to the actual scores led to significant outcomes. It was concluded that fine-grained auditory discrimination is particularly important in the relatively early stages of language learning.
RESUMO
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.