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1.
Gesundheitswesen ; 77 Suppl 1: S78-9, 2015 Sep.
Artículo en Alemán | MEDLINE | ID: mdl-24671890

RESUMEN

The main goal of this study was the evaluation of an intervention programme for the promotion of health literacy in school-aged children (grade 5-6). The project and the programme were highly accepted, the extension of the annual dental health examination was suitable to collect data within evaluation projects in schools. In spite of positive outcomes, a longer supervision phase would be necessary in order to optimise and to implement other programme components fully.


Asunto(s)
Evaluación Educacional/estadística & datos numéricos , Educación en Salud/organización & administración , Alfabetización en Salud/organización & administración , Servicios de Salud Escolar/organización & administración , Estudiantes/estadística & datos numéricos , Niño , Salud Infantil , Femenino , Alemania/epidemiología , Humanos , Masculino , Evaluación de Programas y Proyectos de Salud , Instituciones Académicas
2.
J Mech Behav Biomed Mater ; 150: 106270, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38056402

RESUMEN

OBJECTIVES: The aim of this study was to determine the resistance to impingement damage of three different artificially aged UHMWPE materials used for total hip joint replacement. The results obtained can be used as a basis for an acceptance criterion for testing according to ASTM F2582-20. METHODS: Three different polyethylene liner materials, standard polyethylene (UHMWPE), moderately crosslinked (XLPE) and vitamin E stabilized crosslinked (XLPE-VE) polyethylene of the same design and manufacturer were tested up to one million impingement cycles according to ASTM F2582-20. The liners were artificially oxygen aged for two and three weeks according to ASTM F2003-02. The wear volumes of the liner, acetabular shells, and hip endoprosthesis stems were determined. Each of the six impingement test groups consisted of three samples. For each test group, a reference group was subjected to the same conditioning and loading conditions but without impingement between the hip stem and the liner. The force needed to disassemble the liner from the acetabular shell (push-out force) was determined according to ASTM F1820-22 for the test and the reference groups. RESULTS: XLPE and XLPE-VE polyethylene groups showed less impingement wear when compared to the standard UHMWPE material. Similarly, the protective function of the liner against direct metal-on-metal contact was greater, resulting in less wear on the acetabular shell and the stem neck. The three weeks aged standard UHMWPE group showed early onset of fatigue delamination wear. The push-out values remained unchanged for all XLPE liners and the 3-week aged XLPE-VE liners. The aged UHMWPE liners showed low push-out strength due to component shrinkage caused by aging in combination with the tapered fixation used for this specific design. SIGNIFICANCE: The largest polyethylene wear volume measured of XLPE and XLPE-VE polyethylene aged for two and three weeks was 15.05 mm³ (SD 0.56 mm³). The corresponding metal wear volume was 1.23 mm³ (SD 0.19 mm³) for the acetabular cup and 1.33 mm³ (SD 0.20 mm³) for the stem neck. Those values can support the definition of an acceptance criteria for impingement testing. The results of the push-out test required by ASTM F2582-20 should be evaluated with respect to geometry changes caused by aging. The protective effect of the polyethylene liner against metal-on-metal contact should be considered in the implant design phase in order to avoid implant failure due to metal debris.


Asunto(s)
Artroplastia de Reemplazo de Cadera , Prótesis de Cadera , Humanos , Anciano , Falla de Prótesis , Polietileno , Diseño de Prótesis
3.
Pharmazie ; 66(5): 357-61, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21699069

RESUMEN

PX-18 and PX-13 are secretory phospholipase A2-IIA (sPLA2-IIA) inhibitors. An increased expression of sPLA2 in psoriatic skin has been reported. The selective inhibition of this enzyme is a new therapeutic approach. For dermal application PX-18 and PX-13 have been loaded to Nanostructured lipid carriers (NLC). The PX-18-loaded and PX-13-loaded NLC possessed an average particles size of about 250 nm, a narrow particle size distribution (PI < 0.2), a high entrapment efficiency as well as a good physical stability, as already indicated by their high zeta potential. Both NLC formulations have been incorporated into a hydroxyethyl cellulose gel and an o/w cream. In the gel and in the o/w cream PX-18-loaded and PX-13-loaded NLC showed a good physical stability. Neither aggregation nor dissolution of NLC took place.


Asunto(s)
Alcanosulfonatos/administración & dosificación , Ácidos Alcanesulfónicos/administración & dosificación , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos , Liposomas/química , Nanoestructuras/química , Ácidos Oléicos/administración & dosificación , Inhibidores de Fosfolipasa A2 , Administración Tópica , Alcanosulfonatos/química , Ácidos Alcanesulfónicos/química , Rastreo Diferencial de Calorimetría , Celulosa/análogos & derivados , Química Farmacéutica , Electroquímica , Emulsiones , Rayos Láser , Ácidos Oléicos/química , Tamaño de la Partícula , Fotones , Absorción Cutánea , Espectrofotometría , Termodinámica
4.
Gesundheitswesen ; 72(8-9): e45-50, 2010.
Artículo en Alemán | MEDLINE | ID: mdl-20049684

RESUMEN

AIM OF THE STUDY: Pain in children and adolescents in Germany is a common health problem which has a high socioeconomic impact. There have been no studies allowing a reliable estimation of the prevalence of pain in children in the 5 (th) grade (age range 9-13 years) in schools in the region of the city of Greifswald and the administrative district East Pomerania. This population-based cross-sectional study examined the prevalence of pain in children, the treatment of pain and compared these data with the results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). METHODS: Data were collected within the extended dental school examination in autumn 2007 including a self-completion questionnaire for the students. Also the parents answered a self-completion questionnaire containing questions on their children's socio-economic status. The pain and sociodemographic questions are compatible with those used in the "German Health Survey for Children and Adolescents" (KiGGS). RESULTS: Students from 19 schools completed a questionnaire on general pain (n=852, proportion of response: 93.2%, mean age: 10 years). Comparing to the KiGGS the overall 3-month prevalence is much higher (95.5%). For boys and girls headache is the pain associated with the most burden ("Hauptschmerz"). 1/4 of the girls (27.9%) and 1/5 (22.4%) of the boys reported their pain with the most burden during the last 3 months with a frequency of at least one time per week. Students with low socio-economic status took medication against pain ("Hauptschmerz") less frequently than students with high socio-economic status. Because of their pain ("Hauptschmerz") students with low socio-economic status visited a doctor less often than students with a mean or high socio-economic status. CONCLUSION: Compared to other epidemiological studies, pain is also a common health problem for children in the city of Greifswald and the administrative district East Pomerania. The data base enables comprehensive conclusions on the health-related state of students in Greifswald/East Pomerania. Further studies should examine additional factors on medication and the degree of doctor?s visits, e. g., parental attitudes towards medication and parental motivation towards the degree of visiting a doctor.


Asunto(s)
Manejo del Dolor , Dimensión del Dolor/estadística & datos numéricos , Dolor/epidemiología , Estudiantes/estadística & datos numéricos , Adolescente , Niño , Femenino , Alemania/epidemiología , Humanos , Masculino , Prevalencia , Factores de Riesgo , Encuestas y Cuestionarios , Resultado del Tratamiento
5.
J Forensic Odontostomatol ; 38(1): 8-17, 2020 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-32420908

RESUMEN

Sex determination, which is based on the existence of dimorphism between specimens of the same species, plays an important role in the process of human identification. In the absence of pelvic elements, the skull appears to be the best sex indicator, and can also be submitted to quantitative or metric assessments. Eleven measurements were taken for this study, four in the sagittal plane and seven in the horizontal, in two groups of 186 skulls each, with 101 from males and 85 from females for those of the sagittal plane, and 100 and 86, respectively, for those concerning the horizontal, of subjects aged between 18 and 94 years at the time of death. The sample belongs to the Osteological and Tomographic Biobank Professor Doctor Eduardo Daruge of the Piracicaba Dental School of the University of Campinas. The aim of this research was to establish a reliable method to determine sex and elaborate mathematical prototypes capable of assisting in investigation or identification activities, in a preliminary study. Of the measures implemented (Lambda-Nasion, Lambda-Rhinion, Lambda-Nasospinale, Rhinion-Nasospinale, Zygomaxillare-Zygomaxillare, Lambda-Incisive Foramen, Lambda-Right Zygomaxillare, Lambda-Left Zygomaxillare, Basion-Incisive Foramen, Basion-Right Zygomaxillare and Basion-Left Zygomaxillare), only the Lambda-Nasospinale and Rhinion-Nasospinale in the sagittal plane, and the Zygomaxillare-Zygomaxillare and Lambda-Incisive Foramen in the horizontal plane, were significantly dimorphic. Two predictive mathematical models of sex were conceived for each pair of them: one of logistic regression and another of conditional inference trees, displaying accuracy rates of 78.5% and 77.42%, and of 68.28% and 72.04%, respectively. The authors concluded that there is the possibility to apply the aforementioned data in forensic anthropology as an auxiliary tool in investigation or identification tasks.


Asunto(s)
Determinación del Sexo por el Esqueleto , Cráneo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Brasil , Cefalometría , Femenino , Antropología Forense , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
6.
Sci Rep ; 6: 33591, 2016 09 20.
Artículo en Inglés | MEDLINE | ID: mdl-27646174

RESUMEN

Circadian rhythms in physiology and behavior are modulated by external factors such as light or temperature. We studied whether self-selected office lighting during the habitual waking period had a different impact on alertness, cognitive performance and hormonal secretion in extreme morning and evening chronotypes (N = 32), whose preferred bed- and wake-up times differed by several hours. The self-selected lighting condition was compared with constant bright light and a control condition in dim light. Saliva samples for hormonal analyses, subjective ratings of alertness, wellbeing, visual comfort and cognitive performance were regularly collected. Between the self-selected and the bright, but not the dim lighting condition, the onset of melatonin secretion in the evening (as marker for circadian phase) was significantly different for both chronotypes. Morning chronotypes reported a faster increase in sleepiness during the day than evening chronotypes, which was associated with higher cortisol secretion. Wellbeing, mood and performance in more difficult cognitive tasks were better in bright and self-selected lighting than in dim light for both chronotypes, whereas visual comfort was best in the self-selected lighting. To conclude, self-selection of lighting at work might positively influence biological and cognitive functions, and allow for inter-individual differences.


Asunto(s)
Atención , Ritmo Circadiano/fisiología , Ritmo Circadiano/efectos de la radiación , Cognición , Hormonas/metabolismo , Iluminación , Adolescente , Adulto , Afecto , Femenino , Humanos , Hidrocortisona/metabolismo , Iluminación/efectos adversos , Masculino , Melatonina/metabolismo , Saliva/metabolismo , Sueño/fisiología , Vigilia , Adulto Joven
7.
J Control Release ; 235: 379-392, 2016 08 10.
Artículo en Inglés | MEDLINE | ID: mdl-27302248

RESUMEN

The biodistribution of adenovirus type 5 (Ad5) vector particles is heavily influenced by interaction of the particles with plasma proteins, including coagulation factor X (FX), which binds specifically to the major Ad5 capsid protein hexon. FX mediates hepatocyte transduction by intravenously-injected Ad5 vectors and shields vector particles from neutralization by natural antibodies and complement. In mice, mutant Ad5 vectors that are ablated for FX-binding become detargeted from hepatocytes, which is desirable for certain applications, but unfortunately such FX-nonbinding vectors also become sensitive to neutralization by mouse plasma proteins. To improve the properties of Ad5 vectors for systemic delivery, we developed a strategy to replace the natural FX shield by a site-specific chemical polyethylene glycol shield. Coupling of polyethylene glycol to a specific site in hexon hypervariable region 1 yielded vector particles that were protected from neutralization by natural antibodies and complement although they were unable to bind FX. These vector particles evaded macrophages in vitro and showed significantly improved pharmacokinetics and hepatocyte transduction in vivo. Thus, site-specific shielding of Ad5 vectors with polyethylene glycol rendered vectors FX-independent and greatly improved their properties for systemic gene therapy.


Asunto(s)
Adenovirus Humanos/genética , Factor X/genética , Vectores Genéticos , Animales , Proteínas de la Cápside/química , Proteínas de la Cápside/genética , Línea Celular , Línea Celular Tumoral , Proteínas del Sistema Complemento/inmunología , Cisteína/genética , Femenino , Proteínas Fluorescentes Verdes/genética , Hepatocitos/metabolismo , Humanos , Interleucina-6/sangre , Interleucina-6/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Polietilenglicoles/química , Transducción Genética
8.
J Dent Res ; 95(13): 1464-1471, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27655623

RESUMEN

The authors evaluated the association of reduced bone stiffness of the calcaneus with clinical attachment loss (CAL) and tooth loss. The authors analyzed data from 4,678 subjects (2,384 women), aged 20 to 88 y, from the second follow-up of the population-based Study of Health in Pomerania (SHIP-2) and the baseline examination of the SHIP-Trend cohort. Bone stiffness, characterized by the stiffness index (SI) and the osteoporotic fracture risk (OFR), was assessed by quantitative ultrasound of the heel. SI and OFR were significantly associated with the mean CAL in women. While 1) the SI showed a significant association with the mean CAL and 2) the OFR with the median number of teeth in just the postmenopausal women, the OFR showed a significant association with mean CAL for both pre- and postmenopausal women. In postmenopausal women, a 10-unit increase in the SI was associated with a decrease in the mean CAL of 0.05 mm (95% confidence interval [CI]: -0.10 to 0.00; P = 0.046). Moreover, the adjusted median number of teeth was 21.4 (95% CI: 20.9 to 21.9) among the postmenopausal women with a low OFR, while it was 19.1 (95% CI: 17.8 to 20.3; P = 0.001) among the postmenopausal women with a high OFR. For the premenopausal women with a low OFR, the mean CAL was 1.60 mm (95% CI: 1.53 to 1.66), while for the premenopausal women with a high OFR, it was 2.24 mm (95% CI: 1.78 to 2.69; P = 0.006). Reduced bone stiffness was associated with clinical attachment and tooth loss in women but not in men.


Asunto(s)
Densidad Ósea , Calcáneo/diagnóstico por imagen , Calcáneo/patología , Pérdida de la Inserción Periodontal/epidemiología , Pérdida de Diente/epidemiología , Absorciometría de Fotón , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Alemania/epidemiología , Humanos , Persona de Mediana Edad , Factores de Riesgo
9.
Biomaterials ; 26(3): 311-8, 2005 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-15262473

RESUMEN

The aim of the present study was to investigate the effect of cyclic uniaxial mechanical strain on a human osteoblastic precursor cell line (hFOB 1.19) in three-dimensional type I collagen matrices. Cell seeded collagen constructs were mechanically stretched by a daily application of cyclic uniaxial strain using a special motor-driven apparatus and compared to unstretched controls. Expression of genes involved in cell proliferation and osteoblastic differentiation as well as matrix production were investigated by analyzing the mRNA of histone H4, core binding factor 1, alkaline phosphatase, osteopontin, osteocalcin, and collagen type I (Col I) up to a cultivation period of 3 weeks using real-time PCR. Cyclic stretching of cell seeded Col I matrices at a magnitude occurring in healing bone increased cell proliferation and slightly elevated the expression of nearly all investigated genes over unstrained controls at various time points. It was concluded that mechanical load promotes the proliferation and differentiation of osteoblastic precursor cells in a Col I matrix and that the application of mechanical stimuli may have a beneficial effect on in vitro tissue formation.


Asunto(s)
Sustitutos de Huesos/química , Colágeno Tipo I/química , Mecanotransducción Celular/fisiología , Osteoblastos/citología , Osteoblastos/fisiología , Osteogénesis/fisiología , Ingeniería de Tejidos/métodos , Materiales Biocompatibles/química , Materiales Biomiméticos/química , Reactores Biológicos , Diferenciación Celular/fisiología , Línea Celular , Proliferación Celular , Supervivencia Celular/fisiología , Elasticidad , Matriz Extracelular/química , Matriz Extracelular/fisiología , Humanos , Ensayo de Materiales , Estimulación Física/métodos , Estrés Mecánico
10.
Int J Pharm ; 288(1): 169-75, 2005 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-15607269

RESUMEN

The hydrophobic cyclic undecapeptide cyclosporin A (CyA) used in the prevention of graft rejection and in the treatment of autoimmune diseases was encapsulated by nanoprecipitation within non-biodegradable polymeric nanoparticles. The effect of polymers (Eudragit RS or RL) and additives within the alcoholic phase (fatty acid esters and polyoxyethylated castor oil) on the size, zeta potential and the encapsulation efficiency of the nanoparticles was investigated. The mean diameter of the various CyA nanoparticles ranged from 170 to 310 nm. The size as well as the zeta potential increased by adding fatty acid ester and polyoxyethylated castor oil within the organic phase. No significant differences in surface potential were observed for all formulations tested. Probably due to the very low water solubility of the drug, high encapsulation efficiencies were observed in a range from 70 to 85%. The oral absorption of CyA from these polymeric nanoparticles was studied in rabbits and compared to that of Neoral capsule. Based on comparison of the area under the blood concentration-time curve values, the relative bioavailability of CyA from each nanoparticulate formulation ranged from 20 to 35%.


Asunto(s)
Resinas Acrílicas/administración & dosificación , Ciclosporinas/administración & dosificación , Nanoestructuras , Polímeros/administración & dosificación , Resinas Acrílicas/farmacocinética , Administración Oral , Animales , Ciclosporinas/farmacocinética , Evaluación Preclínica de Medicamentos/métodos , Masculino , Polímeros/farmacocinética , Conejos
11.
Biomaterials ; 21(22): 2215-31, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11026628

RESUMEN

Various research groups around the world are actively investigating cardiovascular prostheses of biological origin. This review article discusses the need for such bioprosthetics and the potential role for natural tissues in cardiovascular applications such as cardiac valves and vascular grafts. Upon implantation, unmodified natural materials are subject to chemical and enzymatic degradation, seriously decreasing the life of the prosthesis. Therefore, methods such as glutaraldehyde and polyepoxide crosslinking treatments and dye-mediated photooxidation have been developed to stabilize the tissue while attempting to maintain its natural mechanical properties. Also, residual cellular components in a bioprosthetic material have been associated with undesired effects, such as calcification and immunological recognition, and thus have been the motivation for various decellularization processes. The effects of these stabilization and decellularization treatments on mechanical, biological and chemical properties of treated tissues have been investigated, specifically with regard to calcification, immunogenicity, and cytotoxicity concerns. Despite significant advances in the area of cardiovascular prostheses, there has yet to be developed a completely biocompatible, long-lasting implant. However, with the recent advent of tissue engineering, the possibility of applying selective cell seeding to naturally derived bioprosthetics moves us closer to a living tissue replacement.


Asunto(s)
Materiales Biocompatibles , Prótesis Vascular , Prótesis Valvulares Cardíacas , Animales , Prótesis Vascular/efectos adversos , Implantación de Prótesis Vascular , Calcinosis , Glutaral , Prótesis Valvulares Cardíacas/efectos adversos , Implantación de Prótesis de Válvulas Cardíacas , Humanos , Diseño de Prótesis
12.
Biomaterials ; 22(10): 1055-64, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11352099

RESUMEN

Electrical charges have been shown to enhance nerve regeneration; however, the mechanisms for this effect are unclear. One hypothesis is that an electrical stimulus alters the local electrical fields of extracellular matrix molecules, changing protein adsorption. We have investigated this hypothesis--that electrical stimulation increases the adsorption of serum proteins, specifically fibronectin (FN), to the electrically conducting polymer polypyrrole (PP), thereby, increasing neurite extension. PP was used because electrical stimulation of PP has been shown to significantly enhance neurite outgrowth, and more importantly, PP can be formed into conduits to guide nerve regeneration in vivo. Here, we looked at the effects of electrical stimulation on protein adsorption when an electrical current was applied to PP (1) during protein adsorption (immediate stimulation) and (2) several hours after protein adsorption (delayed stimulation). We found that immediate stimulation of PP increases FN adsorption from purified FN and serum-containing solutions. Correspondingly, PC-12 cells grown on PP films that had been previously adsorbed with FN during immediate stimulation expressed longer neurites. However, for delayed stimulation, no significant differences in adsorption or neurite outgrowth were observed. These studies suggest that increased FN adsorption with immediate electrical stimulation may explain enhanced neurite extension on electrically stimulated PP.


Asunto(s)
Materiales Biocompatibles , Regeneración Nerviosa/fisiología , Neuronas/metabolismo , Proteínas/metabolismo , Adsorción , Animales , Proteínas Sanguíneas/metabolismo , Bovinos , Comunicación Celular , Medios de Cultivo , Estimulación Eléctrica , Fibronectinas/metabolismo , Ensayo de Materiales , Neuritas/ultraestructura , Neuronas/citología , Células PC12 , Polímeros , Pirroles , Ratas , Soluciones
13.
Biomaterials ; 24(23): 4191-6, 2003 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-12853249

RESUMEN

Regarding orthopaedic implant loosening it has been hypothesized that particle-activated macrophages release interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha). This in turn stimulates osteoblasts to release interleukin-6 (IL-6) and prostaglandin E(2) (PGE(2)). These mediators recruit and activate osteoclasts and may therefore lead to bone resorption and loss of implant fixation. In this study we compared the ability of different materials to induce the release of IL-6 and PGE(2) from primary isolated, human osteoblasts without preceding activation by macrophages. We tested stainless steel, cobalt-chromium alloy (CoCrMo), commercially pure titanium (cpTi), Ti-6Al-7Nb and Ti-6Al-4V processed in the same manner as corresponding clinical implants. After 12 and 24h the cells had actively secreted IL-6 and PGE(2). There were no clear differences among the implant materials or with the plastic control. The amount of factors the cells released in our study compare well with the findings of other authors who investigated osteoblasts on plastic. In comparison with the literature these amounts are lower than secretion levels of osteoblasts stimulated with implant particles, IL-1 or TNF-alpha. Moreover, other authors found that osteoclasts require higher concentrations of PGE(2) to become activated than the concentrations measured in our experiments. Therefore, the amount of PGE(2) released from the osteoblasts in our study is probably not sufficient to induce osteolytic activity. Because of contradictory statements in the literature it is unclear if the measured IL-6 concentrations promote osteolytic activity. Differences in material composition does not significantly influence the release of these factors if the materials have similar surface roughnesses.


Asunto(s)
Materiales Biocompatibles/química , Dinoprostona/metabolismo , Interleucina-6/metabolismo , Osteoblastos/metabolismo , Prótesis e Implantes , Células Cultivadas , Aleaciones de Cromo/química , Humanos , Macrófagos/metabolismo , Acero Inoxidable/química , Factores de Tiempo , Titanio/química
14.
J Control Release ; 57(2): 115-25, 1999 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-9971890

RESUMEN

Besides parenteral delivery, polymeric nanoparticles have been used for oral drug delivery. In this study, model polymeric nanoparticles (aqueous colloidal polymer dispersions: Eudragit(R) RL 30D, L 30D, NE 30D, or Aquacoat(R)) with different physicochemical properties were incorporated into various solid dosage forms (granules, tablets, pellets or films). The compatibility of the nanoparticles with commonly used tabletting excipients and the redispersibility of the nanoparticles after contact of the solid dosage forms with aqueous media were investigated. Ideally, the nanoparticles should be released from the solid dosage forms with their original properties. The addition of polymeric binders (e.g. polyvinylpyrrolidone, Na carboxymethylcellulose or hydroxypropyl methylcellulose) to the aqueous nanoparticle dispersions prior to wet granulation resulted in phase separation (depletion or bridging flocculation) for many nanoparticle/binder systems. Two critical parameters for the complete redispersibility/release of the nanoparticles with the original particle size properties from the solid dosage forms were a (1) high minimum film formation temperature (MFT) of the polymer dispersion and (2) a good wettability of the dried polymeric nanoparticles. Nanoparticle dispersions with a low MFT were not redispersible, they coalesced into larger agglomerates/films during the drying step. Contact angle measurements correlated well with the redispersibility of the nanoparticles, with ethylcellulose particles having high contact angles and poor redispersibility and Eudragit(R) RL, a polymer stabilized with quaternary ammonium groups, having low contact angles and good redispersibility.


Asunto(s)
Excipientes , Polímeros/química , Resinas Acrílicas , Administración Oral , Fenómenos Químicos , Química Física , Geles , Microesferas , Tamaño de la Partícula , Ácidos Polimetacrílicos , Polvos , Comprimidos
15.
Cornea ; 14(1): 26-32, 1995 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-7712732

RESUMEN

The association of glaucoma and penetrating keratoplasty presents a difficult management problem, particularly when medical therapy and conventional glaucoma surgery have failed. We have found alloplastic tube shunt surgery to be an effective method for intraocular pressure control in glaucomatous eyes subjected to penetrating keratoplasty. We report 46 patients who underwent alloplastic tube shunt implantation before (13 patients, group A), in combination with (17 patients, group B), or after (16 patients, group C) penetrating keratoplasty. All groups had significantly lowered intraocular pressure postoperatively. The most common complication was graft failure, in 31% of patients in group A, 29% in group B, and 44% in group C. Other postoperative complications and results including visual outcome are reviewed. Because the management of advanced glaucoma in patients undergoing keratoplasty is difficult, alloplastic tube shunt implantation should be considered.


Asunto(s)
Glaucoma/cirugía , Queratoplastia Penetrante , Implantes de Molteno , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Humanos , Presión Intraocular , Masculino , Persona de Mediana Edad , Plásticos , Complicaciones Posoperatorias , Estudios Retrospectivos , Resultado del Tratamiento , Agudeza Visual
16.
Eur J Cardiothorac Surg ; 7(3): 114-6, 1993.
Artículo en Inglés | MEDLINE | ID: mdl-8384861

RESUMEN

Six years after the first aortic valve replacement with the Starr-Edwards Silastic ball prosthesis at Oregon Health Sciences University, the model 1260 was implanted in a 44-year-old patient at our department. During 24 years no signs of dysfunction, thromboembolism, thrombosis, periprosthetic leaks or hemolysis were observed. Material test showed no signs of fatigue. The dimension of the Silastic poppet was found to be one millimeter less than the original specifications of these poppets and there were some lipid infiltrations. Functionally the poppet was found to be nonvariant. Histologic findings detected focal hyalinization and giant cells without signs of acute inflammation or ulceration. With regard to its reliability and durability, the Starr-Edwards valve prosthesis should not be viewed with disfavor.


Asunto(s)
Estenosis de la Válvula Aórtica/cirugía , Prótesis Valvulares Cardíacas , Adulto , Estenosis de la Válvula Aórtica/rehabilitación , Estudios de Evaluación como Asunto , Estudios de Seguimiento , Reacción a Cuerpo Extraño/etiología , Enfermedades de las Válvulas Cardíacas/complicaciones , Enfermedades de las Válvulas Cardíacas/cirugía , Prótesis Valvulares Cardíacas/efectos adversos , Hemodinámica , Humanos , Masculino , Elastómeros de Silicona , Siliconas
17.
Int J Pharm ; 216(1-2): 9-16, 2001 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-11274801

RESUMEN

As a novel alternative to the incorporation into hard gelatin capsules or tablets, extended-release (Aquacoat- or Eudragit RS-coated) or enteric (Eudragit L-coated) pellets were embedded into congealed tablet-shaped PEG-plugs of different molecular weights, which rapidly released the pellets upon contact with aqueous fluids. The lower-molecular-weight PEGs (600 and 1000) were not suitable carrier materials: they dissolved the coatings or significantly increased their permeability. The release characteristics of the original pellets were maintained after embedding the pellets into the higher-molecular-weight PEGs 4000 or 10000. The shelf-life stability was a function of storage temperature and coating material. Stored at 40 degrees C, Aquacoat-coated pellets embedded in PEG 4000 exhibited a decreased drug release because of curing effects, while storage at 20 degrees C or below resulted in stable release profiles over a 3 month period. Eudragit RS-coated pellets, stored at room temperature or above, showed an increased release, and the carrier material possibly migrated into the film, thus increasing its permeability. At 4 degrees C, the release was stable over a 6 month period.


Asunto(s)
Sistemas de Liberación de Medicamentos , Polietilenglicoles , Teofilina/administración & dosificación , Resinas Acrílicas , Química Farmacéutica , Preparaciones de Acción Retardada , Portadores de Fármacos , Estabilidad de Medicamentos , Ácidos Polimetacrílicos
18.
Clin Plast Surg ; 26(4): 617-28, ix, 1999 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10553217

RESUMEN

Tissue engineering in the peripheral nervous system unites efforts by physicians, engineers, and biologists toward a common goal to create either natural or synthetic tubular nerve guidance channels as alternatives to nerve autografts for the repair of peripheral nerve defects. Guidance channels help direct axons sprouting from the regenerating nerve end, provide a conduit for diffusion of neurotropic and neurotrophic factors secreted by the damaged nerve stumps, and minimize infiltration of fibrous tissue. In addition to efforts to control these physical characteristics of nerve guidance channels, researchers are optimizing the incorporation of biologic factors and engineering interactive biomaterial that can specifically stimulate the regeneration process. It is believed that current and future research will ultimately result in biologically active and interactive nerve guidance channels that can support and enhance peripheral nerve regeneration over longer, more clinically relevant defect lengths.


Asunto(s)
Materiales Biocompatibles , Biotecnología , Regeneración Nerviosa , Nervios Periféricos/fisiología , Animales , Diseño de Equipo , Humanos , Traumatismos de los Nervios Periféricos
19.
Otol Neurotol ; 24(5): 714-6, 2003 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-14501444

RESUMEN

PURPOSE: Surgical blocking of the eustachian tube is presented as an ultimate treatment option in a 11-year-old suicidal boy with a therapy-resistant, persistent clicking tinnitus caused by myoclonus of the levator veli palatini. PATIENT: An 11-year-old boy decompensated psychologically as a result of loud and objective tinnitus. The tinnitus could be heard easily by an examiner by bringing his own ear at a distance of approximately 20 to 30 cm to the left ear of the patient. No neurologic etiology for the tinnitus could be traced. Pediatric psychiatric evaluation resulted in a recommendation to perform, as a last resort, an experimental surgical option like blockage of the eustachian tube. INTERVENTION: Treatment with Tegretol (Novartis, The Netherlands) had no effect. Treatment with Dysport (Ipsen) botulin toxin with 30 to 60 U was temporarily effective. Finally, 60 U were not effective anymore. As last refugium, a surgical blockage of the eustachian tube has been performed, first with bone cement and later by a more conventional surgical blockage of that bony tube. OUTCOME: After surgical blockage of the bony part of the eustachian tube, the objective tinnitus disappeared. Blockage of the protympanum by bone cement resulted in only 1 year of successful blocking. After recurrence of the tinnitus combined with aeration of the middle ear, a second surgical transcanal approach was successful in blocking the eustachian tube. With a grommet, the hearing level remained within 10 dB for 0.5 to 8.0 kHz.


Asunto(s)
Cementos para Huesos/uso terapéutico , Trompa Auditiva/cirugía , Mioclonía/cirugía , Complicaciones Posoperatorias/cirugía , Acúfeno/cirugía , Toxinas Botulínicas/administración & dosificación , Toxinas Botulínicas/efectos adversos , Niño , Trompa Auditiva/fisiopatología , Humanos , Masculino , Mioclonía/fisiopatología , Mioclonía/psicología , Grupo de Atención al Paciente , Reoperación , Riesgo , Prevención Secundaria , Suicidio/psicología , Acúfeno/fisiopatología , Acúfeno/psicología , Insuficiencia del Tratamiento , Prevención del Suicidio
20.
Orthop Clin North Am ; 31(3): 485-98, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10882473

RESUMEN

Tissue engineering in the peripheral nervous system unites efforts by physicians, engineers, and biologists to create either natural or synthetic tubular nerve guidance channels as alternatives to nerve autografts for the repair of peripheral nerve defects. Guidance channels help direct axons sprouting from the regenerating nerve end, provide a conduit for diffusion of neurotropic and neurotrophic factors secreted by the damaged nerve stumps, and minimize infiltration of fibrous tissue. In addition to efforts to control these physical characteristics of nerve guidance channels, researchers are optimizing the incorporation of biologic factors and engineering interactive biomaterial that can specifically stimulate the regeneration process. Current and future research will ultimately result in biologically active and interactive nerve guidance channels that can support and enhance peripheral nerve regeneration over longer, more clinically relevant defect lengths.


Asunto(s)
Regeneración Nerviosa/fisiología , Traumatismos de los Nervios Periféricos , Animales , Materiales Biocompatibles , Humanos , Factores de Crecimiento Nervioso/fisiología , Nervios Periféricos/fisiopatología , Nervios Periféricos/cirugía , Prótesis e Implantes
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