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1.
Eur Arch Otorhinolaryngol ; 280(2): 651-659, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35792917

RESUMO

BACKGROUND: For patients with single sided deafness (SSD) or severe asymmetric sensorineural hearing loss (ASHL), cochlear implantation remains the only solution to restore bilateral hearing capacity. Prognostically, the duration of hearing loss in terms of audiological outcome is not yet clear. Therefore, the aim of this study was to retrospectively investigate the influence of subjective deafness duration on postoperative speech perception after cochlear implantation for SSD as well as its impact on quality of life. MATERIALS AND METHODS: The present study included a total of 36 adults aged 50.2 ± 15.5 years who underwent CI for SSD/ASHL at our clinic between 2010 and 2015. Patients were audiometrically assessed at 3 and 12-36 months postoperatively. Test results were correlated with self-reported duration of deafness. Quality of life was assessed by questionnaire. RESULTS: Mean duration of deafness was 193.9 ± 185.7 months. The side-separated hearing threshold showed an averaged target range between 30 and 40 dB HL. Freiburg monosyllable test increased from 0% pre-operatively to 20% after 3 months (p = 0.001) and to 50% after 12-36 months (p = 0.002). There was a significant correlation between audiometric outcome and subjective deafness duration at 12-36 months postoperatively (r = - 0.564; p = 0.02) with a cutoff for open-set monosyllable recognition at a duration of deafness of greater than 408 months. Quality of life was significantly improved by CI. CONCLUSIONS: CI implantation in unilaterally deafened patients provides objective and subjective benefits. Duration of deafness is unlikely to be an independent negative predictive factor and thus should not generally be considered as contraindication.


Assuntos
Implante Coclear , Implantes Cocleares , Surdez , Perda Auditiva Neurossensorial , Perda Auditiva Unilateral , Percepção da Fala , Adulto , Humanos , Perda Auditiva Unilateral/cirurgia , Inteligibilidade da Fala , Surdez/cirurgia , Surdez/reabilitação , Estudos Retrospectivos , Qualidade de Vida , Resultado do Tratamento , Audição , Perda Auditiva Neurossensorial/cirurgia
2.
J Colloid Interface Sci ; 613: 415-425, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35042039

RESUMO

HYPOTHESIS: Interphase properties in composites, adhesives and protective coatings can be predicted on the basis of interfacial interactions between polymeric precursor molecules and the inorganic surface during network formation. The strength of molecular interactions is expected to determine local segmental mobility (polymer glass transition temperature, Tg) and cure degree. EXPERIMENTS: Conventional analysis techniques and atomic force microscopy coupled with infrared (AFM-IR) are applied to nanocomposite specimens to precisely characterise the epoxy-amine/iron oxide interphase, whilst molecular dynamics simulations are applied to identify the molecular interactions underpinning its formation. FINDINGS: Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and high-resolution AFM-IR mapping confirm the presence of nanoscale under-cured interphase regions. Interfacial segregation of the molecular triethylenetetraamine (TETA) cross-linker results in an excess of epoxy functionality near synthetic hematite, (Fe2O3) magnetite (Fe3O4) and goethite (Fe(O)OH) particle surfaces. This occurs independently of the variable surface binding energies, as a result of entropic segregation during the cure. Thermal analysis and molecular dynamics simulations demonstrate that restricted segmental motion is imparted by strong interfacial binding between surface Fe sites in goethite, where the position of surface hydroxyl protons enables synergistic hydrogen bonding and electrostatic binding to Fe atoms at specific sites. This provides a strong driving force for molecular orientation resulting in significantly raised Tg values for the goethite composite samples.


Assuntos
Compostos Férricos , Óxido Ferroso-Férrico , Aminas , Interfase
3.
Laryngorhinootologie ; 101(7): 585-591, 2022 07.
Artigo em Alemão | MEDLINE | ID: mdl-34763353

RESUMO

BACKGROUND: Sarcoidosis is a granulomatous multisystem disease of unknown etiology and relatively rare. The heterogeneous clinical picture is a diagnostic challenge. We are investigating whether the superficially visible cutaneous lesions can lead to the differential diagnosis of sarcoidosis and what systemic manifestations are present. MATERIAL AND METHODS: As part of our exploratory retrospective investigation (eight years) a total of 32 patients with cutaneous sarcoidosis were identified and analyzed. RESULTS AND CONCLUSION: In many cases the dermatologists considered the differential diagnosis of sarcoidosis even before biopsy (71.8%); in our previous study with ENT-patients the diagnosis wasn't considered in a single case by the attending doctors at this time and without any prevoius suspicion. Sarcoidosis of the skin in the head and neck area is the second most common cutaneous manifestation. After biopsy (Gold standard) the search for further possible organ manifestations is essential (e.g. lungs, heart) to treat them in an early stage and to prevent complications of a possible chronic course (including cardiac arrhythmias, pulmonary fibrosis).


Assuntos
Sarcoidose , Diagnóstico Diferencial , Granuloma/diagnóstico , Humanos , Estudos Retrospectivos , Sarcoidose/diagnóstico , Sarcoidose/patologia , Sarcoidose/terapia , Pele/patologia
4.
Pathogens ; 10(4)2021 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-33916650

RESUMO

(1) Background: Alveolar echinococcosis (AE) is restricted to the northern hemisphere with high endemic regions in Central Europe, North and Central Asia as well as Western China. The larval stage of Echinococcus multilocularis (E. multilocularis) causes AE with tumor-like growth. Humans are accidental hosts. This report is on the first case of AE becoming clinically manifested in the parotic gland. (2) Case presentation: A 52-year-old male patient presented with progressive and painful swelling of the right parotid gland persisting for one year. We performed a partial parotidectomy. The histological examination and immunohistological staining revealed larval stage of E. multilocularis. (3) Conclusion: E. multilocularis is known to infect animals and humans coincidentally, and leads to AE. It is one of the most life-threatening zoonoses in Europe. It typically manifests in the liver (50-77%), with further spreading to other organs being a rare phenomenon. Echinococcosis should be considered in the differential diagnosis of lesions of the parotid gland in endemic areas, but AE has not been described so far in the parotid gland as the sole manifestation and, therefore, impedes the correct diagnosis. A complete resection should be the aim, however, preservation of the facial nerve and adjuvant albendazole therapy is mandatory.

6.
Pediatr Emerg Care ; 37(9): 466-470, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30624421

RESUMO

OBJECTIVE: Epistaxis in children is one of the most common causes for seeking professional medical help. Patients may be treated by several disciplines with various approaches to pediatric epistaxis. We reviewed cases of pediatric epistaxis from an otorhinolaryngologist's point of view. METHODS: A retrospective chart review was performed on all patients younger than 18 years presenting with epistaxis to the Department of Otorhinolaryngology at the University of Bonn, Germany. RESULTS: Sixty episodes of epistaxis in 58 patients were included in the study. Mean age was 10.1 ± 4.5 years. In terms of risk factors, 3 patients had a hemorrhagic diathesis, 3 had taken medication that interfered with hemostasis, and 8 had a history of previous trauma, most of which was digital manipulation. Twenty-six patients did not need invasive therapy. Twenty-six patients received cauterization to control the bleeding, and 4 patients needed surgery. The necessity for surgery was mainly noncooperation. CONCLUSIONS: Epistaxis in children is seldom serious. However, hemorrhagic diathesis needs to be kept in mind as a potential cause of epistaxis. In most cases, careful instruction of the patients and the relatives concerning nasal mucosal care is sufficient. If cauterization is necessary, silver nitrate coagulation should be preferred over electrocoagulation.


Assuntos
Epistaxe , Transtornos Hemorrágicos , Adolescente , Cauterização , Criança , Pré-Escolar , Epistaxe/etiologia , Epistaxe/terapia , Humanos , Estudos Retrospectivos , Fatores de Risco
7.
Plast Reconstr Surg Glob Open ; 8(11): e3216, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33299692

RESUMO

Thrombosis is a serious complication of a hyaluronic acid-based filler injection. Little is known about the late-onset complications of fillers; therefore, an optimal complication management is necessary. In this case report, we describe a rare complication of thrombosis after a filler injection. A 35-year old woman was admitted to the emergency department, with swelling on her forehead in association with recurrent pain and light flashes in her right eye. Sonographic examination showed a thrombosis of the right frontal vein. The patient reported that a hyaluronic acid filler injection had been administered on the forehead 3 months ago. After several weeks of anticoagulation with heparin and apixaban, the symptoms persisted. The vein with thrombosis was ultimately resected under local anesthesia. Histological findings showed a chronic inflammatory reaction of the tissue to hyaluronic acid. Vascular complications may appear as late-onset complications even several months after the filler injection. Subcutaneous application of low molecular weight heparins is the therapy of first choice. If this treatment is not effective, resection of the thrombosis may be performed.

8.
Langmuir ; 36(29): 8485-8493, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32506911

RESUMO

Polymer brushes not only represent emerging surface platforms for numerous bioanalytical and biological applications but also create advanced surface-tethered systems to mimic real-life biological processes. In particular, zwitterionic and nonionic polymer brushes have been intensively studied because of their extraordinary resistance to nonspecific adsorption of biomolecules (antifouling characteristics) as well as the ability to be functionalized with bioactive molecules. However, the relation between antifouling behavior in real-world biological media and structural changes of polymer brushes induced by surface preconditioning in different environments remains unexplored. In this work, we use multiple methods to study the structural properties of numerous brushes under variable ionic concentrations and determine the impact of these changes on resistance to fouling from undiluted blood plasma. We describe different mechanisms of swelling, depending on both the polymer brush coating properties and the environmental conditions that affect changes in both hydration levels and thickness. Using both fluorescent and surface plasmon resonance methods, we found that the antifouling behavior of these brushes is strongly dependent on the aforementioned structural changes. Moreover, preconditioning of the brush coatings (incubation at a variable salt concentration or drying) prior to biomolecule interaction may significantly improve the antifouling performance. These results suggest a new simple approach to improve the antifouling behavior of polymer brushes. In addition, the results herein enhance the understanding for improved design of antifouling and bioresponsive brushes employed in biosensor and biomimetic applications.

9.
Appl Spectrosc ; 74(9): 1185-1197, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32436395

RESUMO

Determining microplastics in environmental samples quickly and reliably is a challenging task. With a largely automated combination of optical particle analysis, Fourier transform infrared (FT-IR), and Raman microscopy along with spectral database search, particle sizes, particle size distributions, and the type of polymer including particle color can be determined. We present a self-developed, open-source software package for realizing a particle analysis approach with both Raman and FT-IR microspectroscopy. Our software GEPARD (Gepard Enabled PARticle Detection) allows for acquiring an optical image, then detects particles and uses this information to steer the spectroscopic measurement. This ultimately results in a multitude of possibilities for efficiently reviewing, correcting, and reporting all obtained results.


Assuntos
Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Microplásticos/análise , Software , Ensaios de Triagem em Larga Escala , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman
10.
Br J Neurosurg ; 34(5): 495-499, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30295542

RESUMO

Objective: Sarcoidosis is a multisystemic granulomatous disease of unknown cause which affects the lung or bilateral hilar lymphadenopathy in over 90% of the cases. Neurosarcoidosis (NS) is rare and accounts for approximately 5 - 15% of the cases. Involvement of all parts of the central and peripheral nervous system is possible with various clinical symptoms, e. g. seizures, hydrocephalus, optic/facial nerve palsy or hearing loss.Methods: We screened the neuropathological data bases and the medical records of two neurosurgical university hospitals for cases of NS. All these cases had been verified by surgical biopsy. We retrospectively evaluated the patient's records with special regard to the histopathology reports and specific clinical symptoms.Results: We identified 9 cases of NS between 1994 and 2014 (3 female, 6 male patients). The average age at the time of diagnosis of NS was 41,4 years. Various clinical symptoms like hydrocephalus (n = 3), seizures (n = 1), meningitis (n = 1), optical nerve involvment with vision disorder (n = 1), myelitis with paraplegia (n = 1), mastoiditis with hearing loss (n = 1), back pain syndrome (n = 2) were present. 7 patients were treated with corticosteroids, 1 patient with cyclophosphamide and 1 with a combination of corticosteroids and methotrexate.Conclusion: NS is a rare but potentially life-threatening disease. It is difficult to distinguish sarcoidosis from other granulomatous diseases, infectious diseases like tuberculosis, multiple sclerosis or neoplasm. For a definite diagnosis, a neurosurgical biopsy with histological evidence of noncaseating epithelioid cell granulomas is required, followed by multidisciplinary treatment.


Assuntos
Doenças do Sistema Nervoso Central , Sarcoidose , Adulto , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Estudos Retrospectivos
11.
Sci Rep ; 9(1): 18839, 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31806865

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

12.
Sci Rep ; 9(1): 15207, 2019 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-31645581

RESUMO

Microplastics (MP) data collection from the aquatic environment is a challenging endeavour that sets apparent limitations to regional and global MP quantification. Expensive data collection causes small sample sizes and oftentimes existing data sets are compared without accounting for natural variability due to hydrodynamic processes governing the distribution of particles. In Warnow estuarine sediments (Germany) we found significant correlations between high-density polymer size fractions (≥500 mm) and sediment grain size. Among potential predictor variables (source and environmental terms) sediment grain size was the critical proxy for MP abundance. The MP sediment relationship can be explained by the force necessary to start particle transport: at the same level of fluid motion, transported sediment grains and MP particles are offset in size by one to two orders of magnitude. Determining grain-size corrected MP abundances by fractionated granulometric normalisation is recommended as a basis for future MP projections and identification of sinks and sources.

13.
Artigo em Inglês | MEDLINE | ID: mdl-31355127

RESUMO

Objective/Hypothesis: Spontaneous rhinoliquorrhea often occurs due to defects of the skull base. It is often misinterpreted as rhinitis and is surgically the most difficult rhinoliquorrhea entity to close. Methods: We conducted a retrospective chart analysis of patients that were diagnosed with spontaneous rhinoliquorrhea at the University Hospital Bonn between 2001 and 2017. Results: Overall, twelve patients were included in this study. On average, the time between occurrence of nasal discharge and diagnoses of rhinoliquorrhea was 123 days. In ten patients, the localization of the skull base defect could be localized by computed tomography or MRI cisternography. Ten patients underwent surgery, of which 9 remained recurrence free. One patient underwent revision surgery and from thereon was recurrence free. Conclusion: Spontaneous rhinoliquorrhea still remains a diagnostic and therapeutic challenge. Whenever persistent watery nasal discharge appears in a patient, rhinoliquorrhea must be considered. Endoscopic surgical reconstruction of the skull base is the therapeutic gold standard and should be attempted as soon as the diagnosis is secured.

14.
Front Chem ; 7: 101, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30899756

RESUMO

Herein, we report on the use of a combined setup of quartz-crystal microbalance, with dissipation monitoring and spectroscopic ellipsometry, to comprehensively investigate the covalent immobilization of an enzyme to a polymer layer. All steps of the covalent reaction of the model enzyme glucose oxidase with the poly(acrylic acid) brush by carbodiimide chemistry, were monitored in-situ. Data were analyzed using optical and viscoelastic modeling. A nearly complete collapse of the polymer chains was found upon activation of the carboxylic acid groups with N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide and N-Hydroxysuccinimide. The reaction with the amine groups of the enzyme occurs simultaneously with re-hydration of the polymer layer. Significantly more enzyme was immobilized on the surface compared to physical adsorption at similar conditions, at the same pH. It was found that the pH responsive swelling behavior was almost not affected by the presence of the enzyme.

15.
Eur Arch Otorhinolaryngol ; 276(7): 1969-1974, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30900021

RESUMO

BACKGROUND: Sarcoidosis is a chronic disease, which predominantly affects the lung. Since sinonasal sarcoidosis is rare, little is known about the sarcoidosis manifestation at this site. Therefore, the aim of our study was to detect the prevalence of sinonasal sarcoidosis, its clinical occurrence, diagnosis, and therapy. METHODS: The database of all patients having visited the otorhinolaryngology departments of the universities in Göttingen and in Bonn between 2003 and 2016 was searched for the diagnosis of sinonasal sarcoidosis. RESULTS: Thirteen patients with a biopsy-proven sinonasal sarcoidosis were identified. Most patients presented non-specific clinical symptoms, which are also found in acute and chronic sinusitis. None of the patients was suspected to have sinonasal sarcoidosis by the ENT doctor before histological validation. The mean diagnostic delay was 262 (± 195) days. An additional pulmonary involvement was detected in four of six patients. CONCLUSIONS: Sinonasal sarcoidosis is presenting with heterogeneous clinical presentations. An early biopsy of granulomatous lesions is mandatory. A multidisciplinary approach is needed to exclude serious lung or heart manifestations, because even asymptomatic organ involvement is possible. A CT-scan may be useful even if unspecific. Local or systemic therapy has to be prepared individually using local and systemic corticosteroids, antimetabolites, or anti-TNF-alpha.


Assuntos
Doenças dos Seios Paranasais , Seios Paranasais , Sarcoidose , Biópsia/métodos , Diagnóstico Tardio/prevenção & controle , Feminino , Alemanha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Doenças dos Seios Paranasais/diagnóstico , Doenças dos Seios Paranasais/epidemiologia , Doenças dos Seios Paranasais/terapia , Seios Paranasais/diagnóstico por imagem , Seios Paranasais/patologia , Administração dos Cuidados ao Paciente/métodos , Sarcoidose/diagnóstico , Sarcoidose/epidemiologia , Sarcoidose/terapia , Tomografia Computadorizada por Raios X/métodos
17.
Langmuir ; 35(9): 3479-3489, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30742441

RESUMO

Catalysis by enzymes on surfaces has many applications. However, strategies for efficient enzyme immobilization with preserved activity are still in need of further development. In this work, we investigate polyelectrolyte brushes prepared by both grafting-to and grafting-from with the aim to achieve high catalytic activity. For comparison, self-assembled monolayers that bind enzymes with the same chemical interactions are included. We use the model enzyme glucose oxidase and two kinds of polymers: anionic poly(acrylic acid) and cationic poly(diethylamino)methyl methacrylate. Surface plasmon resonance and spectroscopic ellipsometry are used for accurate quantification of surface coverage. Besides binding more enzymes, the "3D-like" brush environment enhances the specific activity compared to immobilization on self-assembled monolayers. For grafting-from brushes, multilayers of enzymes were spontaneously and irreversibly immobilized without conjugation chemistry. When the pH was between the pI of the enzyme and the p Ka of the polymer, binding was considerable (thousands of ng/cm2 or up to 50% of the polymer mass), even at physiological ionic strength. However, binding was observed also when the brushes were neutrally charged. For acidic brushes (both grafting-to and grafting-from), the activity was higher for covalent immobilization compared to noncovalent. For grafting-from brushes, a fully preserved specific activity compared to enzymes in the liquid bulk was achieved, both with covalent (acidic brush) and noncovalent (basic brush) immobilization. Catalytic activity of hundreds of pmol cm-2 s-1 was easily obtained for polybasic brushes only tens of nanometers in dry thickness. This study provides new insights for designing functional interfaces based on enzymatic catalysis.


Assuntos
Enzimas Imobilizadas/metabolismo , Glucose Oxidase/metabolismo , Polieletrólitos/metabolismo , Resinas Acrílicas/química , Resinas Acrílicas/metabolismo , Adsorção , Enzimas Imobilizadas/química , Glucose Oxidase/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Metacrilatos/química , Metacrilatos/metabolismo , Nylons/química , Nylons/metabolismo , Polieletrólitos/química , Ligação Proteica , Ressonância de Plasmônio de Superfície
18.
Laryngoscope ; 129(2): 403-408, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30151958

RESUMO

OBJECTIVES/HYPOTHESIS: Salivary fistulas are a common minor complication of parotid surgery. botulinum toxin has repeatedly been reported to be an adequate treatment of this entity. To date, there is little scientific evidence for clinical decision making after appearance of a salivary fistula. STUDY DESIGN: Retrospective chart analysis of 16 patients who had been treated with botulinum toxin for salivary fistula. METHODS: All patients who had been treated for salivary fistula at a tertiary referral hospital from 2010 to 2016 were included. Patient files were used to obtain characteristics of patients, treatment, and follow-up. RESULTS: Sixteen patients with salivary fistula received 27 injections of botulinum toxin. Nine patients required one injection for the fistula to heal, five patients needed two injections, and one patient needed three and four injections, respectively. No patient underwent additional surgery or radiotherapy. We observed no adverse effects in any patient treated with botulinum toxin. CONCLUSIONS: In most cases of salivary fistula, injections of botulinum toxin are a valid treatment. If the initial injection is not successful, injections may be repeated once. Otherwise, revision surgery should be considered. In general, treatment with botulinum toxin should be commenced in an earlier stage and with higher dosages. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:403-408, 2019.


Assuntos
Toxinas Botulínicas Tipo A/administração & dosagem , Fármacos Neuromusculares/administração & dosagem , Doenças Parotídeas/cirurgia , Complicações Pós-Operatórias/tratamento farmacológico , Fístula das Glândulas Salivares/tratamento farmacológico , Idoso , Feminino , Seguimentos , Humanos , Injeções , Masculino , Pessoa de Meia-Idade , Glândula Parótida/cirurgia , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Fístula das Glândulas Salivares/etiologia , Resultado do Tratamento
19.
Int Forum Allergy Rhinol ; 9(1): 120-124, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30281938

RESUMO

BACKGROUND: Epistaxis is one of the more common reasons for emergency room visits. The main risk factor for epistaxis is anticoagulant therapy. Until recently, the main culprit was oral intake of a vitamin K antagonist, such as warfarin, which has a number of side effects. Even more recently, several direct oral anticoagulants, rivaroxaban and dabigatran, have been approved for use. We investigated the possible differences between treatment of epistaxis with direct oral anticoagulants and vitamin K antagonists. METHODS: We conducted a retrospective cohort study at a tertiary referral center in Germany. All patients who were admitted within a 1-year period were included. Patient files were used to obtain the information. RESULTS: Overall, 677 patients were included in our study. Of these, 159 had been treated with vitamin K antagonists and 49 with direct oral anticoagulants. There were no significant differences in terms of age (p = 0.592), sex (p = 0.372), vital signs, bloodwork, or location of bleeding (p = 0.372). Management of epistaxis between the groups was also comparable (p = 0.399), with similar hospital admission rates (37.1% vs 24.5%; p = 0.145) and duration of stay (3.5 ± 2.1 days vs 3.8 ± 3.3 days; p = 0.650). CONCLUSION: We found no evidence to suggest epistaxis is more severe or requires more invasive therapy in patients given direct oral anticoagulants. A significant proportion of patients on vitamin K antagonists were not within the target range for international normalized ratio, highlighting one of the main issues with oral anticoagulation by vitamin K antagonists.


Assuntos
Anticoagulantes/efeitos adversos , Dabigatrana/efeitos adversos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Epistaxe/epidemiologia , Rivaroxabana/efeitos adversos , Varfarina/efeitos adversos , Administração Oral , Idoso , Idoso de 80 Anos ou mais , Anticoagulantes/uso terapêutico , Estudos de Coortes , Dabigatrana/uso terapêutico , Epistaxe/etiologia , Feminino , Seguimentos , Alemanha/epidemiologia , Hospitalização/estatística & dados numéricos , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Estudos Retrospectivos , Risco , Rivaroxabana/uso terapêutico , Resultado do Tratamento , Varfarina/uso terapêutico
20.
Biointerphases ; 13(6): 06D405, 2018 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-30227717

RESUMO

The authors report on highly swellable, stable layers of spherical dendritic glycopolymers, composed of hyperbranched poly(ethylene imine) (PEI) as core and two different maltose shells (A = dense shell and B = open shell). These glycopolymers are cross-linked and attached with poly(ethylene-alt-maleic anhydride) (PEMA) or citric acid on SiOx substrates. The swelling and adsorption of biomolecules were analyzed by spectroscopic ellipsometry and quartz crystal microbalance with dissipation. The swelling degree and complexation with the drug molecule adenosine triphosphate (ATP) were found to be up to 10 times higher for dendritic glycopolymer layers cross-linked with PEMA than for layers cross-linked with citric acid. ATP complexation by electrostatic interaction with the PEI cores was confirmed by x-ray photoelectron spectroscopy analysis. Complexation led to partial collapsing, stiffening, and increase of polymer layer viscosity of the PEMA cross-linked layers. From modeling of ellipsometric data, it was deduced that ATP complexation preferably takes place at the polymer layer-solution interface. The size effect of the adsorbates was investigated by comparing ATP complexation with the adsorption of larger vitamin B12 and human serum albumin (HSA) protein. PEI-Mal A cross-linked with PEMA was found to be resistant toward B12 and HSA adsorption due to the diffusion barrier of the polymer layer. Thus, the authors present potentially biocompatible polymer surfaces for drug loading and their surface supported release.


Assuntos
Adsorção , Fatores Biológicos/metabolismo , Dendrímeros/metabolismo , Iminas/metabolismo , Polietilenos/metabolismo , Polissacarídeos/metabolismo , Trifosfato de Adenosina/metabolismo , Dendrímeros/química , Iminas/química , Polietilenos/química , Polissacarídeos/química , Técnicas de Microbalança de Cristal de Quartzo , Albumina Sérica Humana/metabolismo , Análise Espectral , Vitamina B 12/metabolismo
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