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1.
Am J Physiol Heart Circ Physiol ; 320(3): H1199-H1212, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33449853

RESUMO

CaMKII is needed for the recovery of Ca2+ transients during acidosis but also mediates postacidic arrhythmias. CaMKIIδ can sustain its activity following Met281/282 oxidation. Increasing cytosolic Na+ during acidosis as well as postacidic pH normalization should result in prooxidant conditions within the cell favoring oxidative CaMKIIδ activation. We tested whether CaMKIIδ activation through Met281/282 oxidation is involved in recovery of Ca2+ transients during acidosis and promotes cellular arrhythmias post-acidosis. Single cardiac myocytes were isolated from a well-established mouse model in which CaMKIIδ was made resistant to oxidative activation by knock-in replacement of two oxidant-sensitive methionines (Met281/282) with valines (MM-VV). MM-VV myocytes were exposed to extracellular acidosis (pHo 6.5) and compared to wild type (WT) control cells. Full recovery of Ca2+ transients was observed in both WT and MM-VV cardiac myocytes during late-phase acidosis. This was associated with comparably enhanced sarcoplasmic reticulum Ca2+ load and preserved CaMKII specific phosphorylation of phospholamban at Thr17 in MM-VV myocytes. CaMKII was phosphorylated at Thr287, but not Met281/282 oxidized. In line with this, postacidic cellular arrhythmias occurred to a similar extent in WT and MM-VV cells, whereas inhibition of CaMKII using AIP completely prevented recovery of Ca2+ transients during acidosis and attenuated postacidic arrhythmias in MM-VV cells. Using genetically altered cardiomyocytes with cytosolic expression of redox-sensitive green fluorescent protein-2 coupled to glutaredoxin 1, we found that acidosis has a reductive effect within the cytosol of cardiac myocytes despite a significant acidosis-related increase in cytosolic Na+. Our study shows that activation of CaMKIIδ through Met281/282 oxidation is neither required for recovery of Ca2+ transients during acidosis nor relevant for postacidic arrhythmogenesis in isolated cardiac myocytes. Acidosis reduces the cytosolic glutathione redox state of isolated cardiac myocytes despite a significant increase in cytosolic Na+. Pharmacological inhibition of global CaMKII activity completely prevents recovery of Ca2+ transients and protects from postacidic arrhythmias in MM-VV myocytes, which confirms the relevance of CaMKII in the context of acidosis.NEW & NOTEWORTHY The current study shows that activation of CaMKIIδ through Met281/282 oxidation is neither required for CaMKII-dependent recovery of Ca2+ transients during acidosis nor relevant for the occurrence of postacidic cellular arrhythmias. Despite a usually prooxidant increase in cytosolic Na+, acidosis reduces the cytosolic glutathione redox state within cardiac myocytes. This novel finding suggests that oxidation of cytosolic proteins is less likely to occur during acidosis.


Assuntos
Acidose/enzimologia , Arritmias Cardíacas/enzimologia , Sinalização do Cálcio , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Frequência Cardíaca , Miócitos Cardíacos/enzimologia , Acidose/complicações , Animais , Arritmias Cardíacas/etiologia , Arritmias Cardíacas/fisiopatologia , Técnicas Biossensoriais , Proteínas de Ligação ao Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Feminino , Glutationa/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Concentração de Íons de Hidrogênio , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Contração Miocárdica , Oxirredução , Fosforilação , Espécies Reativas de Oxigênio/metabolismo
2.
Infection ; 49(2): 349-353, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32779123

RESUMO

Leptospirosis is an infectious disease with an increasing incidence worldwide. The clinical presentation is unspecific and ranges from an asymptomatic clinical course to an acute fulminant disease. The current case report describes a 32-year-old male patient who presented with ST segment elevation in the electrocardiogram about 14 days after cross-country running. Pericarditis was diagnosed and linked to an acute leptospirosis that was serologically confirmed.


Assuntos
Leptospirose , Pericardite , Doença Aguda , Adulto , Eletrocardiografia , Humanos , Leptospirose/complicações , Leptospirose/diagnóstico , Masculino , Pericardite/diagnóstico
3.
Am J Physiol Heart Circ Physiol ; 319(6): H1347-H1357, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33035439

RESUMO

Reactive oxygen species (ROS) have been shown to prolong cardiac action potential duration resulting in afterdepolarizations, the cellular basis of triggered arrhythmias. As previously shown, protein kinase A type I (PKA I) is readily activated by oxidation of its regulatory subunits. However, the relevance of this mechanism of activation for cardiac pathophysiology is still elusive. In this study, we investigated the effects of oxidation-activated PKA I on cardiac electrophysiology. Ventricular cardiomyocytes were isolated from redox-dead PKA-RI Cys17Ser knock-in (KI) and wild-type (WT) mice and exposed to H2O2 (200 µmol/L) or vehicle (Veh) solution. In WT myocytes, exposure to H2O2 significantly increased oxidation of the regulatory subunit I (RI) and thus its dimerization (threefold increase in PKA RI dimer). Whole cell current clamp and voltage clamp were used to measure cardiac action potentials (APs), transient outward potassium current (Ito) and inward rectifying potassium current (IK1), respectively. In WT myocytes, H2O2 exposure significantly prolonged AP duration due to significantly decreased Ito and IK1 resulting in frequent early afterdepolarizations (EADs). Preincubation with the PKA-specific inhibitor Rp-8-Br-cAMPS (10 µmol/L) completely abolished the H2O2-dependent decrease in Ito and IK1 in WT myocytes. Intriguingly, H2O2 exposure did not prolong AP duration, nor did it decrease Ito, and only slightly enhanced EAD frequency in KI myocytes. Treatment of WT and KI cardiomyocytes with the late INa inhibitor TTX (1 µmol/L) completely abolished EAD formation. Our results suggest that redox-activated PKA may be important for H2O2-dependent arrhythmias and could be important for the development of specific antiarrhythmic drugs.NEW & NOTEWORTHY Oxidation-activated PKA type I inhibits transient outward potassium current (Ito) and inward rectifying potassium current (IK1) and contributes to ROS-induced APD prolongation as well as generation of early afterdepolarizations in murine ventricular cardiomyocytes.


Assuntos
Potenciais de Ação , Subunidade RIalfa da Proteína Quinase Dependente de AMP Cíclico/metabolismo , Frequência Cardíaca , Miócitos Cardíacos/enzimologia , Canais de Potássio/metabolismo , Potássio/metabolismo , Animais , Subunidade RIalfa da Proteína Quinase Dependente de AMP Cíclico/genética , Ativação Enzimática , Peróxido de Hidrogênio/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Miócitos Cardíacos/efeitos dos fármacos , Oxirredução , Estresse Oxidativo , Canais de Potássio/efeitos dos fármacos , Multimerização Proteica , Fatores de Tempo
4.
J Mol Cell Cardiol ; 118: 159-168, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29614261

RESUMO

RATIONALE: Ca/calmodulin-dependent protein kinase II (CaMKII) was shown to increase diastolic sarcoplasmic reticulum (SR) Ca leak, which can result in delayed afterdepolarizations and triggered arrhythmias. Since increased CaMKII expression and activity has been mechanistically linked to arrhythmias in human heart failure (HF) and atrial fibrillation (AF), specific strategies aimed at CaMKII inhibition may have therapeutic potential. OBJECTIVE: We tested the antiarrhythmic and inotropic effects of a novel selective and ATP-competitive CaMKII inhibitor (GS-680). METHODS AND RESULTS: Trabeculae were isolated from right atrial appendage biopsies of patients undergoing cardiac surgery. Premature atrial contractions (PACs) were induced by stimulation with isoproterenol (ISO, 100 nM) at increased [Ca]o (3.5 mM). Interestingly, compared to vehicle, PACs were significantly inhibited by exposure to GS-680 (at 100 and 300 nM). GS-680 also significantly decreased early and delayed afterdepolarizations in isolated human atrial myocytes. Moreover, GS-680 (at 100 or 300 nM) significantly inhibited diastolic SR Ca leak, measured as frequency of spontaneous SR Ca release events (Ca sparks) in isolated human atrial myocytes (Fluo-4 loaded) similar to the well-established peptide CaMKII inhibitor AIP. In accordance, GS-680 significantly reduced CaMKII autophosphorylation (Western blot) but enhanced developed tension after 10 or 30 s pause of electrical stimulation (post-rest behavior). Surprisingly, we found a strong negative inotropic effect of GS-680 in atrial trabeculae at 1 Hz stimulation rate, which was not observed at 4 Hz and abolished by beta-adrenergic stimulation. In contrast, GS-680 did not impair systolic force of isolated ventricular trabeculae from explanted hearts of heart transplant recipients at 1 Hz, blunted the negative force-frequency relationship (1-3 Hz) and significantly increased the Ca transient amplitude. CONCLUSION: The novel ATP-competitive and selective CaMKII inhibitor GS-680 inhibits pro-arrhythmic activity in human atrium and improves contractility in failing human ventricle, which may have therapeutic implications.


Assuntos
Arritmias Cardíacas/enzimologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Piridinas/farmacologia , Pirrolidinas/farmacologia , Tiofenos/farmacologia , Arritmias Cardíacas/complicações , Arritmias Cardíacas/patologia , Arritmias Cardíacas/fisiopatologia , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Diástole/efeitos dos fármacos , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/fisiopatologia , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/fisiopatologia , Humanos , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Fosforilação , Inibidores de Proteínas Quinases/química , Piridinas/química , Pirrolidinas/química , Retículo Sarcoplasmático/efeitos dos fármacos , Retículo Sarcoplasmático/metabolismo
5.
Infection ; 43(2): 229-30, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25380568

RESUMO

Ross River virus (RRV) is an arbovirus transmitted by Aedes and Culex mosquitos. It is endemic in Australia, New Zealand and south-east Asia. Clinical manifestation rates in adults range about 20-40%. Symptoms involve arthralgia, myalgia, lymphadenopathy, fever and rash. Here we report a case of RRV in a Thuringian traveller who visited the urban South-East of Australia.


Assuntos
Infecções por Alphavirus/diagnóstico , Infecções por Alphavirus/virologia , Ross River virus , Viagem , Feminino , Alemanha , Humanos , Pessoa de Meia-Idade , Austrália do Sul
6.
Osteoporos Int ; 25(4): 1369-78, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24504100

RESUMO

UNLABELLED: The effects of bisphosphonates on altered bone turnover marker (BTM) levels associated with adjuvant endocrine or chemotherapy in early breast cancer have not been systematically investigated. In ProBONE II, zoledronic acid decreased these elevated BTM levels and increased bone mineral density (BMD) during adjuvant therapy, consistent with its antiresorptive effects. INTRODUCTION: Adjuvant chemotherapy or endocrine therapy for early hormone receptor-positive breast cancer (HR(+) BC) is associated with rapid BMD loss and altered BTM levels. Adjuvant bisphosphonate studies demonstrated BMD increases, but did not investigate BTM effects. The randomized, double-blind, ProBONE II study investigated the effect of adjuvant zoledronic acid (ZOL) on BMD and BTM in premenopausal women with early HR(+) BC. METHODS: Seventy premenopausal women with early HR(+) BC received adjuvant chemotherapy and/or endocrine therapy plus ZOL (4 mg IV every 3 months) or placebo for 24 months. Primary endpoint was change in lumbar spine BMD at 24 months versus baseline. Secondary endpoints included femoral neck and total femoral BMD changes, changes in BTM, and safety. RESULTS: Lumbar spine BMD increased 3.14% from baseline to 24 months in ZOL-treated participants versus a 6.43% decrease in placebo-treated participants (P < 0.0001). Mean changes in T- and Z-scores, and femoral neck and total femoral BMD, showed similar results. Bone resorption marker levels decreased ∼ 55% in ZOL-treated participants versus increases up to 65% in placebo-treated participants (P < 0.0001 for between-group differences). Bone formation marker (procollagen I N-terminal propeptide) levels decreased ∼ 57% in ZOL-treated participants versus increases up to 45% in placebo-treated participants (P < 0.0001 for between-group differences). Adverse events were consistent with the established ZOL safety profile and included one case of osteonecrosis of the jaw after a tooth extraction. CONCLUSIONS: Adding ZOL to adjuvant therapy improved BMD, reduced BTM levels, and was well tolerated in premenopausal women with early HR(+) BC receiving adjuvant chemotherapy and/or endocrine therapy.


Assuntos
Antineoplásicos/efeitos adversos , Conservadores da Densidade Óssea/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Difosfonatos/uso terapêutico , Imidazóis/uso terapêutico , Osteoporose/prevenção & controle , Adulto , Densidade Óssea/efeitos dos fármacos , Conservadores da Densidade Óssea/efeitos adversos , Conservadores da Densidade Óssea/farmacologia , Remodelação Óssea/efeitos dos fármacos , Neoplasias da Mama/fisiopatologia , Quimioterapia Adjuvante , Difosfonatos/efeitos adversos , Difosfonatos/farmacologia , Método Duplo-Cego , Feminino , Fêmur/fisiopatologia , Humanos , Imidazóis/efeitos adversos , Imidazóis/farmacologia , Vértebras Lombares/fisiopatologia , Pessoa de Meia-Idade , Osteoporose/induzido quimicamente , Osteoporose/fisiopatologia , Pré-Menopausa/fisiologia , Receptores de Estrogênio/análise , Receptores de Progesterona/análise , Resultado do Tratamento , Adulto Jovem , Ácido Zoledrônico
7.
Infection ; 42(6): 1061-4, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25234200

RESUMO

Schistosomiasis is a widespread helminthic infection which sometimes may affect travelers to endemic areas. We report on a case of urogenital and placental schistosomiasis in a 28-year-old German woman who had been exposed to schistosomiasis in Lake Malawi one year earlier. She experienced painless macrohaematuria in her 21st week of pregnancy. Cystoscopy revealed vesical lesions typical for urogenital schistosomiasis. Histopathology confirmed ova of Schistosoma (S.) haematobium. The patient was treated with praziquantel 40 mg/kg/body weight/day for 3 days. After 285 days of gestation and 18 weeks post treatment, the patient delivered a healthy girl. Histopathology of placenta revealed eggs of S. haematobium in placental stroma. The infant proved negative for anti-Schistosoma spp. antibodies at the age of 15 months. This is the first report on placental schistosomiasis since 1980 and the first case occurring in a traveler.


Assuntos
Doenças Placentárias/parasitologia , Complicações Parasitárias na Gravidez/parasitologia , Schistosoma haematobium/isolamento & purificação , Esquistossomose Urinária/diagnóstico , Adulto , Animais , Feminino , Alemanha , Humanos , Malaui , Gravidez , Viagem
8.
Mult Scler ; 19(5): 631-8, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23069874

RESUMO

BACKGROUND: Cognitive decline has been recognised as a frequent symptom in multiple sclerosis (MS). Cholinesterase inhibitors (ChEIs) are employed for the treatment of Alzheimer's disease, but there is some evidence that ChEIs might also be effective in MS patients with cognitive deficits, particularly deficits of memory function. OBJECTIVE: The aim of this study was to evaluate efficacy on memory function and safety of the ChEI rivastigmine in MS patients with cognitive deficits as measured by the change from baseline of the total recall score of the selective reminding test (SRT) after 16 weeks of treatment. METHODS: Efficacy and safety of rivastigmine were analysed in a 16-week, multicentre, double-blind, randomised, placebo-controlled study, followed by an optional one-year open-label treatment phase. Effects of rivastigmine and placebo were compared by an analysis of covariance. RESULTS: In total, 86 patients were enrolled. Patients who received rivastigmine (n = 43) showed a non-significant increase in total recall score (sum of all words immediately recalled over all six trials) over placebo (n = 38) after 16 weeks of treatment (p = 0.2576). Other outcome measures provided no evidence supporting benefits of rivastigmine. Treatment with rivastigmine was well tolerated. CONCLUSIONS: With the results of this study, the need for an effective therapy in cognitively impaired MS patients is still required. Thus, intensive and continued clinical research is required to explore therapeutic options for cognitive deficits in MS patients.


Assuntos
Inibidores da Colinesterase/uso terapêutico , Transtornos Cognitivos/tratamento farmacológico , Esclerose Múltipla/complicações , Fenilcarbamatos/uso terapêutico , Adulto , Transtornos Cognitivos/etiologia , Método Duplo-Cego , Feminino , Humanos , Masculino , Rememoração Mental , Pessoa de Meia-Idade , Rivastigmina , Resultado do Tratamento
9.
Ann Hematol ; 92(2): 191-8, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23073603

RESUMO

The majority of patients with myelodysplastic syndrome (MDS) present with anemia and will become dependent on regular transfusions of packed red blood cells (PRBC) with the risk of iron overload (IOL). Liver iron content best reflects the total body iron content, and measurement of liver iron concentration (LIC) by MRI is a validated tool for detection, but data in MDS is rather limited. Here we present the results of a multi-center trial evaluating the efficacy and safety of deferasirox (DFX) in low and intermediate-1 risk MDS patients with transfusion-dependent IOL. Three patients with transfusion frequency of > 4 units PRBC per month were initially treated with 30 mg/kg/day while in 46 patients with a lower transfusion burden deferasirox was initiated at 20 mg/kg/day, due to patient related reasons one patient received DFX in a dose of 6 mg/kg/day only. LIC was measured by MRI at baseline and end of study using the method by St. Pierre et al. The intention to treat population consisted of 50 MDS patients (28 male; 22 female) with a median age of 69 years who were treated with DFX for a median duration of 354 days. Mean daily dose of DFX was 19 mg/kg/day. Median serum ferritin level (SF) at baseline was 2,447 ng/mL and decreased to 1,685 ng/mL (reduction by 31 %) at end of study (p = 0.01). In 7 (13 %) patients the initially chosen dose had to be increased due to unsatisfactory efficacy of chelation therapy. For 21 patients, LIC measurement by liver MRI was performed at baseline and for 19 of these patients at the end of study: mean LIC decreased significantly from 16,8 mg/g dry tissue weight (± 8.3 mg/g dry tissue weight) at study entry to 10,8 mg/g dry tissue weight (± 10.4 mg/g dry tissue weight) at end of study (p = 0.01). Of all patients exposed to the study drug (n = 54), 28 (52 %) did not complete the 12 month study period most commonly due to AEs in 28 % (n = 15) and abnormal laboratory values in 7 % (n = 4), respectively. The most common adverse events (≥ 10 % of all patients) with suspected drug relationship were diarrhea (n = 25, 46 %), nausea (n = 13, 24 %), upper abdominal pain (n = 8, 15 %), serum creatinine increase (n = 16, 30 %) and rash (n = 5, 9 %). Adverse events making dose adjustments or interruption of study drug necessary occurred in 33 patients (61 %). Hematologic improvement according to IWG criteria (2006) was observed in 6 patients (11 %). Initiation of treatment of IOL with DFX depending on the transfusion burden yields sufficient reduction of excess iron indicated by serum ferritin levels and most importantly by liver MRI. The safety profile of DFX was comparable to previous observations.


Assuntos
Benzoatos/uso terapêutico , Terapia por Quelação , Quelantes de Ferro/uso terapêutico , Sobrecarga de Ferro/tratamento farmacológico , Síndromes Mielodisplásicas/terapia , Reação Transfusional , Triazóis/uso terapêutico , Administração Oral , Adulto , Idoso , Idoso de 80 Anos ou mais , Benzoatos/administração & dosagem , Benzoatos/efeitos adversos , Terapia por Quelação/efeitos adversos , Creatinina/sangue , Deferasirox , Toxidermias/etiologia , Feminino , Ferritinas/sangue , Gastroenteropatias/induzido quimicamente , Humanos , Ferro/análise , Quelantes de Ferro/administração & dosagem , Quelantes de Ferro/efeitos adversos , Sobrecarga de Ferro/etiologia , Fígado/química , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/epidemiologia , Risco , Resultado do Tratamento , Triazóis/administração & dosagem , Triazóis/efeitos adversos
10.
Osteoporos Int ; 23(7): 2043-51, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22086310

RESUMO

SUMMARY: The ROSE study compared annual infusion with zoledronic acid and weekly generic alendronate. No significant differences in quality of life or health status between treatment groups were observed. Adherence to alendronate during the study was high, with 80.9% of patients achieving adequate adherence. INTRODUCTION: A secondary analysis to evaluate quality of life, health status, adherence to alendronate and therapy preference in postmenopausal women with low bone mass who received treatment with zoledronic acid or alendronate was conducted. METHODS: Postmenopausal women with low bone mass were randomised 2:1 to receive an annual infusion of zoledronic acid or weekly oral generic alendronate in this open-label, multicentre study. Changes in quality of life and health status were assessed using questionnaires at baseline and month 12. Adherence to alendronate was assessed by the investigator and/or study personnel, and subjective therapy preference was assessed using a questionnaire at month 12. RESULTS: Patients were randomised to zoledronic acid (n = 408) and alendronate (n = 191). Overall, there were no significant differences in quality of life between zoledronic acid and alendronate. However, improvements in quality of life with zoledronic acid versus alendronate could be detected by posthoc analysis in patients with previous fractures. There were no significant differences in health status between patients receiving zoledronic acid or alendronate. Adherence to alendronate during the study was high, with 80.9% of patients achieving adequate adherence. A total of 81% of patients who had received zoledronic acid indicated that they would prefer to continue with that treatment, and 43% of the patients who received oral alendronate would like to switch to zoledronic acid. CONCLUSIONS: There were no significant differences in quality of life between patients receiving zoledronic acid or alendronate.


Assuntos
Alendronato/uso terapêutico , Conservadores da Densidade Óssea/uso terapêutico , Difosfonatos/uso terapêutico , Imidazóis/uso terapêutico , Osteoporose Pós-Menopausa/tratamento farmacológico , Qualidade de Vida , Atividades Cotidianas , Administração Oral , Idoso , Idoso de 80 Anos ou mais , Alendronato/administração & dosagem , Conservadores da Densidade Óssea/administração & dosagem , Difosfonatos/administração & dosagem , Esquema de Medicação , Medicamentos Genéricos , Feminino , Nível de Saúde , Humanos , Imidazóis/administração & dosagem , Infusões Intravenosas , Adesão à Medicação , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/reabilitação , Preferência do Paciente , Psicometria , Ácido Zoledrônico
11.
Nature ; 438(7067): 479-82, 2005 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-16306988

RESUMO

Picosecond and femtosecond spectroscopy allow the detailed study of carrier dynamics in nanostructured materials. In such experiments, a laser pulse normally excites several nanostructures at once. However, spectroscopic information may also be acquired using pulses from an electron beam in a modern electron microscope, exploiting a phenomenon called cathodoluminescence. This approach offers several advantages. The multimode imaging capabilities of the electron microscope enable the correlation of optical properties (via cathodoluminescence) with surface morphology (secondary electron mode) at the nanometre scale. The broad energy range of the electrons can excite wide-bandgap materials, such as diamond- or gallium-nitride-based structures that are not easily excited by conventional optical means. But perhaps most intriguingly, the small beam can probe a single selected nanostructure. Here we apply an original time-resolved cathodoluminescence set-up to describe carrier dynamics within single gallium-arsenide-based pyramidal nanostructures with a time resolution of 10 picoseconds and a spatial resolution of 50 nanometres. The behaviour of such charge carriers could be useful for evaluating elementary components in quantum computers, optical quantum gates or single photon sources for quantum cryptography.

12.
Int J Clin Pract ; 65(7): 790-6, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21645184

RESUMO

BACKGROUND: Cholinesterase inhibitors form the mainstay of treatment for persons with mild-to-moderate Alzheimer's disease (AD). The rivastigmine patch may increase compliance and the proportion of patients maintaining an efficacious dose compared with oral cholinesterase inhibitors. OBJECTIVE: To investigate the proportion of patients who reached and maintained the target rivastigmine patch dose compared with the target rivastigmine capsule dose reported in clinical trials. METHODS: This was a multicentre, 24-week, open-label study in persons with probable AD and a Mini-Mental State Examination (MMSE) score of ≥ 10 and ≤ 26. The primary outcome was the proportion of patients (ITT population) treated with 9.5 mg/24 h rivastigmine patch for at least 8 weeks at week 24. Secondary outcomes included week 24 MMSE, Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change (ADCS-CGIC), Trail Making Test Part A (TMT-A) and Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) scores. RESULTS: Overall, 208 participants received treatment and 155 (74.5%) completed the study. Within the ITT population, 147/182 patients (80.8%; 95% CI 75.0-86.5%) were treated for at least 8 weeks with the 9.5 mg/24 h rivastigmine patch; 135/182 patients (74.2%; 95% CI 67.8-80.5%) were treated for at least 8 weeks and completed the study. The most common adverse events were nausea (10.1% of patients), erythema (8.7%), pruritus (8.2%) and vomiting (7.2%). At week 24, patients treated with the rivastigmine patch showed improvements on MMSE, ADCS-ADL, ADCS-CGIC and TMT-A scores. Caregivers reported acceptance, preference and satisfaction with the patch. CONCLUSION: Transdermal delivery may allow more patients to reach and maintain therapeutic doses of rivastigmine compared with oral rivastigmine.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Inibidores da Colinesterase/administração & dosagem , Fármacos Neuroprotetores/administração & dosagem , Fenilcarbamatos/administração & dosagem , Adesivo Transdérmico , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Inibidores da Colinesterase/efeitos adversos , Cognição/efeitos dos fármacos , Feminino , Humanos , Masculino , Adesão à Medicação , Fármacos Neuroprotetores/efeitos adversos , Fenilcarbamatos/efeitos adversos , Rivastigmina , Resultado do Tratamento
13.
Clin Nephrol ; 69(6): 425-32, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18538118

RESUMO

BACKGROUND: End stage renal disease (ESRD) patients mainly die of cardiovascular disease, and hypertension is regarded as the major risk factor. Valsartan is an angiotensin receptor blocker (ARB) with a well-established efficacy and safety profile in hypertensive patients, but with relatively few data in patients on hemodialysis (HD). The aim of this 2 A 5-week, open-label, multicenter, randomized cross-over study was to investigate whether valsartan (Val) 80 mg is as effective, safe and well-tolerated as irbesartan (Irb) 150 mg in patients with arterial hypertension on long-term hemodialysis. METHODS: After a wash-out of previous ARBs for 1 week, 67 patients (ITT) on long-term hemodialysis, between 18 and 80 years, with mean supine systolic blood pressure (MSupSBP) >or= 140 mmHg and < 180 mmHg were randomized to either Val 40 or Irb 75 for 1 week with forced titration to Val 80 or Irb 150 for another 4 weeks. After a second wash-out period of 1 week, patients were switched from Val to Irb or vice versa for another 5 weeks (1 week low-dose, 4 weeks target dose). The primary objective was non-inferiority of Val versus Irb on predialytic MSupSBP. Secondary objectives were predialytic MSupDBP, adverse events (AEs), laboratory abnormalities, hypotension during and after dialysis and quality of life. BP values are given as mean A+/- SD. RESULTS: Baseline BP values were 158 A+/- 11 / 78 A+/- 13 mmHg (Val) and 161 A+/- 13 / 83 A+/- 10 mmHg (Irb). The predialytic MSupSBP and MSupDBP after 4 weeks of treatment were similar in both treatment groups (Val 150 A+/- 19 / 79 A+/- 13 mmHg; Irb 151 A+/- 16 / 78 A+/- 14 mmHg). Most of the reported AEs were mild to moderate. The percentage of AEs considered by the investigator to be possibly drug-related was similar between both groups: 15.4% in the valsartan group and 20.4% in the irbesartan group. The most common AEs were nausea, muscle spasms and nasopharyngitis. Eight SAEs occurred, four in each treatment group (all not drug-related), including one death (cardiovascular insufficiency) in the Irb group. Laboratory changes were similar in both groups and not clinically relevant. The number of patients with symptomatic hypotension was similar during (9% each) as well as after dialysis (1.3% each). The quality of life data (SF-36) were comparable for each category. CONCLUSIONS: Valsartan 80 mg is as effective, safe and well tolerated as irbesartan 150 mg in hypertensive patients on chronic hemodialysis.


Assuntos
Anti-Hipertensivos/uso terapêutico , Compostos de Bifenilo/uso terapêutico , Hipertensão/tratamento farmacológico , Falência Renal Crônica/terapia , Tetrazóis/uso terapêutico , Valina/análogos & derivados , Idoso , Estudos Cross-Over , Feminino , Humanos , Hipertensão/complicações , Irbesartana , Falência Renal Crônica/complicações , Masculino , Pessoa de Meia-Idade , Diálise Renal , Resultado do Tratamento , Valina/uso terapêutico , Valsartana
14.
Mult Scler J Exp Transl Clin ; 4(1): 2055217318756688, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29479457

RESUMO

BACKGROUND: Fatigue is a major symptom of multiple sclerosis (MS) in patients, and it has been shown to improve with physical exercise. Although fingolimod might lessen fatigue, it is unclear how patients treated with fingolimod react to physical activity regarding fatigue. OBJECTIVE: This study evaluated the effect of an exercise intervention on fatigue in relapsing-remitting MS patients receiving fingolimod. METHODS: People with MS (PwMS) were randomized to either a structured internet-based exercise program (e-training) or no e-training intervention. The primary endpoint was the change in the Modified Fatigue Impact Scale (mFIS) after six months. RESULTS: The primary analysis showed no statistically significant difference between groups in the mFIS change. Subgroup analyses revealed a beneficial effect of physical exercise for PwMS with low aerobic capacity and with low aerobic capacity plus more severe fatigue. The incidence of adverse events was similar in both groups. No cardiovascular events were reported. The majority of PwMS were relapse free. CONCLUSION: Physical exercise benefits on fatigue may depend on the physical capacity of the patient and requires individualized training. Consistent with previous studies, these results suggest that physical exercise generally does not impose a risk and that this holds true also for patients receiving fingolimod.Trial registration: ClinicalTrials.gov, NCT01490840.

15.
Int J Antimicrob Agents ; 51(2): 213-220, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29111434

RESUMO

The spread of antimicrobial resistance challenges the empirical treatment of urinary tract infections (UTIs). Among others, nitrofurantoin is recommended for first-line treatment, but acceptance among clinicians is limited due to chronic nitrofurantoin-induced lung toxicity and insufficient coverage of Enterobacteriaceae other than Escherichia coli. Nitroxoline appears to be an alternative to nitrofurantoin owing to its favourable safety profile, however data on its current in vitro susceptibility are sparse. In this study, susceptibility to nitroxoline was tested against 3012 urinary clinical isolates (including multidrug-resistant bacteria and Candida spp.) by disk diffusion test and/or broth microdilution. At least 91% of all Gram-negatives (n = 2000), Gram-positives (n = 403) and yeasts (n = 132) had inhibition zone diameters for nitroxoline ≥18 mm. Except for Pseudomonas aeruginosa, nitroxoline MIC90 values were ≤16 mg/L and were 2- to >16-fold lower compared with nitrofurantoin. In extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae and methicillin-resistant Staphylococcus aureus (MRSA), MIC90 values of nitroxoline were two-fold higher compared with non-ESBL-producing enterobacteria and methicillin-susceptible S. aureus (MSSA). The in vitro efficacies of nitroxoline and nitrofurantoin against ATCC strains of E. coli, Enterococcus faecalis and Proteus mirabilis were compared by time-kill curves in Mueller-Hinton broth and artificial urine. Nitroxoline was non-inferior against E. coli, P. mirabilis and E. faecalis in artificial urine. In conclusion, nitroxoline showed a broad antimicrobial spectrum, with inhibition zone diameters and MICs of nitroxoline well below the EUCAST breakpoint for E. coli for most organisms, and thus may also be a target for therapy of uncomplicated UTIs.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Anti-Infecciosos Urinários/farmacologia , Candida/efeitos dos fármacos , Enterobacteriaceae/efeitos dos fármacos , Nitrofurantoína/farmacologia , Nitroquinolinas/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Candida/isolamento & purificação , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Farmacorresistência Bacteriana Múltipla , Enterobacteriaceae/isolamento & purificação , Humanos , Pseudomonas aeruginosa/isolamento & purificação , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/microbiologia
16.
Ophthalmologe ; 104(4): 336-44, 2007 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-17372736

RESUMO

BACKGROUND: Recent years have seen tremendous progress in our understanding of the mechanisms of neovascular diseases of the eye. Antiangiogenic treatment options are now widely used in the management of age-related maculopathy (AMD) and diabetic retinopathy. The aim of this article is to highlight some novel methods of local antiangiogenic treatment of the cornea and conjunctiva and in the anterior chamber of the eye. METHODS: The study took the form of a literature review (PUBMED) and a review of the authors' own data. RESULTS: Initial experience with novel inhibitors of angiogenesis, especially bevacizumab, used locally on cornea and conjunctiva is promising. Intracameral injections of VEGF inhibitors can be used to ameliorate neovascular glaucoma. CONCLUSION: Novel antiangiogenic drugs are available for topical use in the anterior segment of the eye (as off-label use) and will improve the management of neovascular diseases affecting cornea and conjunctiva and in the anterior chamber of the eye.


Assuntos
Inibidores da Angiogênese/administração & dosagem , Neovascularização da Córnea/tratamento farmacológico , Fator A de Crescimento do Endotélio Vascular/administração & dosagem , Humanos , Guias de Prática Clínica como Assunto , Padrões de Prática Médica/tendências , Resultado do Tratamento
18.
Ophthalmologe ; 113(5): 443-52, 2016 May.
Artigo em Alemão | MEDLINE | ID: mdl-27142037

RESUMO

Neurofibromatosis 1 (NF1) and neurofibromatosis 2 (NF2) are characterized by an autosomal dominant pattern of inheritance with irregular penetrance and a broad spectrum of different clinical phenotypes. There are large variations in the age of onset, progression and prognosis. Symptoms are often manifested early in childhood. Characteristics which the two main forms NF1 and NF2 have in common are a positive family history, characteristic skin alterations, such as café au lait macules, axillary or inguinal freckling and neural tumors such as neurofibroma and optic glioma (NF1) as well as (bilateral) vestibular schwannomas (NF2). An interdisciplinary cooperation is necessary for the diagnostics and therapy.


Assuntos
Neoplasias Oculares/diagnóstico , Neoplasias Oculares/terapia , Neurofibromatoses/diagnóstico , Neurofibromatoses/terapia , Diagnóstico Diferencial , Medicina Baseada em Evidências , Humanos , Avaliação de Sintomas/métodos , Resultado do Tratamento
19.
J Clin Oncol ; 11(10): 2002-9, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8410125

RESUMO

PURPOSE: To determine the maximally tolerated dose of mitoxantrone in combination with cytarabine in patients with acute leukemia and advanced phases of chronic myelogenous leukemia (CML), and to assess the pharmacokinetics of high-dose mitoxantrone in this patient population. PATIENTS AND METHODS: In a phase I study, 68 patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL), and accelerated- and blastic-phase CML received induction therapy consisting of cytarabine 3 g/m2 by infusion over 3 hours daily for 5 days, with escalating doses of mitoxantrone 40 to 80 mg/m2 over 1 to 2 days by intravenous infusion over 15 minutes. Mitoxantrone pharmacokinetics were evaluated by high-performance liquid chromatography (HPLC) in 15 patients given a single dose of mitoxantrone ranging from 40 to 80 mg/m2 in combination with cytarabine. RESULTS: Severe, but reversible hyperbilirubinemia (> three times normal) was considered the dose-limiting toxicity, and was observed in 25% of all patients and in 35% of those who received 70 to 80 mg/m2 of mitoxantrone. Other extramedullary toxicity, including cardiac dysfunction, was mild. Myelosuppression was universal and the median time to complete remission (CR) was 28 days (range, 19 to 77). The CR rate for previously untreated and relapsed patients with AML was 85% (17 of 20) and 38% (seven of 18), respectively. Eighty-three percent (15 of 18) of patients with ALL achieved a CR, including all patients with previously untreated disease. Eight of 12 patients with advanced-phase CML achieved a CR. No significant changes in mean mitoxantrone plasma elimination rates (ie, terminal plasma half-life and total-body clearance rate) occurred as the mitoxantrone dose doubled, indicating linear pharmacokinetics. CONCLUSIONS: The recommended phase II dose of mitoxantrone is 80 mg/m2 administered over 15 minutes as a single intravenous infusion in combination with cytarabine 3 g/m2/d for 5 days. At this dose, high concentrations of mitoxantrone are achievable in vivo to levels that have been shown to be extremely cytotoxic in vitro.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Crise Blástica/tratamento farmacológico , Leucemia Mieloide de Fase Acelerada/tratamento farmacológico , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Doença Hepática Induzida por Substâncias e Drogas , Citarabina/administração & dosagem , Citarabina/farmacocinética , Esquema de Medicação , Feminino , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Mitoxantrona/administração & dosagem , Mitoxantrona/farmacocinética
20.
J Clin Oncol ; 11(9): 1652-60, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8102639

RESUMO

PURPOSE: To determine the toxicities and maximum-tolerated dose of cyclosporine (CsA) administered with daunorubicin as a modulator of multidrug resistance (MDR) in acute leukemia, and to evaluate response to treatment and its relationship to mdr1 gene expression. PATIENTS AND METHODS: Patients with poor-risk acute myeloid leukemia (AML) received sequential treatment with cytarabine (3 g/m2/d intravenously [i.v.]) days 1 to 5, and daunorubicin (45 mg/m2/d) plus CsA as a 72-hour continuous infusion (CI) days 6 through 8 in a phase I/II trial. A loading dose of CsA administered over 1 to 2 hours preceded the CI. CsA dose escalations ranged from 1.4 to 6 mg/kg (load) and 1.5 to 20 mg/kg/d (CI). Whole-blood concentrations of CsA were monitored by immunoassay; plasma concentration of daunorubicin and daunorubicinol were determined by high-pressure liquid chromatography (HPLC). Specimens were analyzed for P-glycoprotein expression, and results confirmed by a quantitative RNA polymerase chain reaction (PCR) assay for the mdr1 gene transcript. RESULTS: Forty-two patients are assessable for toxicity and response. P-glycoprotein was detected in 70% of cases. Dose-dependent CsA toxicities included nausea and vomiting (22%), hypomagnesemia (61%), burning dysesthesias (21%), and prolongation of myelosuppression. Transient hyperbilirubinemia developed in 62% of treatment courses and was CsA-dose-dependent. Reversible azotemia occurred in three patients receiving concurrent treatment with potentially nephrotoxic antibiotics. Steady-state blood concentrations of CsA > or = 1,500 ng/mL were achieved in all patients receiving CI doses > or = 16 mg/kg/d. Mean plasma daunorubicin, but not daunorubicinol, levels were significantly elevated in patients who developed hyperbilirubinemia (P = .017). Twenty-six (62%) patients achieved a complete remission (CR) or restored chronic phase and three patients achieved a partial remission (PR) for an overall response rate of 69% (95% confidence interval, 54% to 84%). The response rate was higher in patients who developed hyperbilirubinemia (P = .001), whereas MDR phenotype did not influence response to treatment. Among five patients with MDR-positive leukemia, cellular mdr1 mRNA decreased (n = 1) or was absent from relapsed specimens (n = 4), while mdr1 RNA remained undetectable at relapse in two patients who were MDR-negative before treatment. CONCLUSION: High doses of CsA, which achieve blood concentrations capable of reversing P-glycoprotein-mediated anthracycline resistance in vitro, can be incorporated into induction regimens with acceptable nonhematologic toxicity. Transient hyperbilirubinemia occurs commonly with CsA administration and may alter daunorubicin pharmacokinetics. Recommended doses of CsA for phase II and III trials are a load of 6 mg/kg and CI of 16 mg/kg/d.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Ciclosporina/uso terapêutico , Leucemia Mieloide/tratamento farmacológico , Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Doença Aguda , Adolescente , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Proteínas de Transporte/genética , Criança , Pré-Escolar , Ciclosporina/efeitos adversos , Ciclosporina/farmacocinética , Daunorrubicina/administração & dosagem , Resistência a Medicamentos/genética , Feminino , Expressão Gênica , Humanos , Leucemia Mieloide/sangue , Leucemia Mieloide/genética , Masculino , Glicoproteínas de Membrana/genética , Pessoa de Meia-Idade , Proteínas de Neoplasias/genética , Fenótipo , Análise de Sobrevida , Resultado do Tratamento
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