Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Bone Marrow Transplant ; 49(10): 1330-6, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25068429

RESUMO

The feasibility of symptom-limited cardiopulmonary exercise testing (CPET) prior to allo-SCT was assessed in addition to the prognostic value of CPET-derived measures. CPET was performed prospectively on 21 patients with hematologic malignancies, with assessments of peak (for example, peak oxygen consumption, VO2peak) and submaximal (for example, ventilatory threshold (VT)) measures of cardiopulmonary function. No serious adverse events were observed during CPET procedures, with 95% of patients achieving criteria for a peak test. Mean VO2peak was 24.7±6.4 mL kg(-1 )min(-1) (range: 10.9-35.5), equivalent to 29%±17% below that of age-matched healthy controls. All patients proceeded with the conditioning regimen followed by allo-SCT. Median follow-up was 25 months. During this period, 11 (52.4%) patients died (n=6, relapsed disease; n=5, non-relapse mortality (NRM)); 9 patients (43%) developed pulmonary toxicity. In univariate analyses, both peak and submaximal markers of cardiopulmonary function were predictors of OS, pulmonary toxicity and NRM. For OS, the HR for VO2peak and VT were 0.89 (95% CI, 0.8-0.99, P=0.04) and 0.84 (95% CI, 0.71-0.98, P=0.03), respectively. In conclusion, CPET is safe and feasible prior to allo-SCT. Patients have marked impairments in cardiopulmonary function prior to allo-SCT. CPET-derived metrics may complement conventional measures to improve risk stratification.


Assuntos
Teste de Esforço/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Condicionamento Pré-Transplante/métodos , Adulto , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Adulto Jovem
2.
J Virol ; 88(10): 5391-405, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24574406

RESUMO

UNLABELLED: The herpes simplex virus (HSV) tegument protein VP1-2 contains an N-terminal nuclear localization signal (NLS) that is critical for capsid routing to the nuclear pore. Here we analyzed positionally conserved determinants in VP1-2 homologues from each of the alpha, beta, and gamma classes of human herpesviruses. The overall architectures of the VP1-2s were similar, with a conserved N-terminal ubiquitin-specific protease domain separated from an internal region by a linker that was quite poorly conserved in length and sequence. Within this linker region all herpesviruses contained a conserved, highly basic motif which nevertheless exhibited distinct class-specific features. The motif in HSV functioned as a monopartite NLS, while in varicella-zoster virus (VZV) activity required an adjacent basic section defining the motif as a bipartite NLS. Neither the beta- nor gammaherpesvirus VP1-2 motifs were identified by prediction algorithms, but they nevertheless functioned as efficient NLS motifs both in heterologous transfer assays and in HSV VP1-2. Furthermore, though with different efficiencies and with the exception of human herpesvirus 8 (HHV-8), these chimeric variants rescued the replication defect of an HSV mutant lacking its NLS motif. We demonstrate that the lysine at position 428 of HSV is critical for replication, with a single alanine substitution being sufficient to abrogate NLS function and virus growth. We conclude that the basic motifs of each of the VP1-2 proteins are likely to confer a similar function in capsid entry in the homologous setting and that while there is flexibility in the exact type of motif employed, specific individual residues are critical for function. IMPORTANCE: To successfully infect cells, all herpesviruses, along with many other viruses, e.g., HIV, hepatitis B virus, and influenza virus, must navigate through the cytoplasmic environment and dock with nuclear pores for transport of their genomes into the nucleus. However, we still have a limited understanding of the detailed mechanisms involved. Insight into these events is needed and could offer opportunities for therapeutic intervention. This work investigated the role of a specific determinant in the structural protein VP1-2 in herpesvirus entry. We examined this determinant in representative VP1-2s from all herpesvirus subfamilies, demonstrated NLS function, dissected key residues, and showed functional relevance in rescuing replication of the mutant blocked in capsid navigation to the pore. The results are important and strongly support our conclusions of the generality that these motifs are crucial for entry of all herpesviruses. They also facilitate future analysis on selective host interactions and possible routes to disrupt function.


Assuntos
Herpesviridae/fisiologia , Sinais de Localização Nuclear , Proteínas Estruturais Virais/metabolismo , Replicação Viral , Transporte Ativo do Núcleo Celular , Animais , Linhagem Celular , Sequência Conservada , Análise Mutacional de DNA , Herpesviridae/genética , Humanos , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Proteínas Estruturais Virais/genética
3.
Bone Marrow Transplant ; 47(5): 700-5, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-21804612

RESUMO

Primary graft failure after allogeneic hematopoietic cell transplantation is a life-threatening complication. A shortened conditioning regimen may reduce the risk of infection and increase the chance of survival. Here, we report the outcome of 11 patients with hematologic diseases (median age, 44; range, 25-67 years, seven males) who received a 1-day reduced-intensity preparative regimen given as a re-transplantation for primary graft failure. The salvage regimen consisted of fludarabine, cyclophosphamide, alemtuzumab and TBI, all administered 1 day before re-transplantation. All patients received T-cell replete PBSCs from the same or a different haploidentical donor (n=10) or from the same matched sibling donor (n=1). Neutrophil counts promptly increased to >500/µL for 10 of the 11 patients at a median of 13 days. Of these, none developed grade III/IV acute GVHD. At present, 8 of the 11 patients are alive with a median follow-up of 11.2 months from re-transplantation and 5 of the 8 are in remission. In conclusion, this series suggests that our 1-day preparative regimen is feasible, leads to successful engraftment in a high proportion of patients, and is appropriate for patients requiring immediate re-transplantation after primary graft failure following reduced-intensity transplantation.


Assuntos
Transplante de Células-Tronco Hematopoéticas/métodos , Terapia de Salvação/métodos , Condicionamento Pré-Transplante/métodos , Adulto , Idoso , Alemtuzumab , Anticorpos Monoclonais Humanizados/uso terapêutico , Ciclofosfamida/uso terapêutico , Feminino , Sobrevivência de Enxerto , Doença Enxerto-Hospedeiro/prevenção & controle , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Reoperação , Estudos Retrospectivos , Transplante Homólogo/efeitos adversos , Vidarabina/análogos & derivados , Vidarabina/uso terapêutico
4.
J Bone Joint Surg Br ; 92(1): 83-91, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20044684

RESUMO

In order to compare the outcome from surgical repair and physiotherapy, 103 patients with symptomatic small and medium-sized tears of the rotator cuff were randomly allocated to one of the two approaches. The primary outcome measure was the Constant score, and secondary outcome measures included the self-report section of the American Shoulder and Elbow Surgeons score, the Short Form 36 Health Survey and subscores for shoulder movement, pain, strength and patient satisfaction. Scores were taken at baseline and after six and 12 months by a blinded assessor. Nine patients (18%) with insufficient benefit from physiotherapy after at least 15 treatment sessions underwent secondary surgical treatment. Analysis of between-group differences showed better results for the surgery group on the Constant scale (difference 13.0 points, p - 0.002), on the American Shoulder and Elbow surgeons scale (difference 16.1 points, p < 0.0005), for pain-free abduction (difference 28.8 degrees , p = 0.003) and for reduction in pain (difference on a visual analogue scale -1.7 cm, p < 0.0005).


Assuntos
Artroscopia/normas , Modalidades de Fisioterapia/normas , Lesões do Manguito Rotador , Manguito Rotador/cirurgia , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Satisfação do Paciente , Amplitude de Movimento Articular , Índice de Gravidade de Doença , Resultado do Tratamento
5.
J Cell Physiol ; 223(1): 84-93, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20049852

RESUMO

Common in vitro protocols for chondrogenesis of mesenchymal stem cells (MSCs) induce an inadequate, hypertrophic differentiation cascade reminiscent of endochondral bone formation. We aimed to modify chondrogenic protocols in order to identify potent inducers, promotors, and inhibitors to achieve better chondrogenesis. Nine factors suspected to stimulate or inhibit chondrogenesis were used for chondrogenic in vitro induction of MSC. Differentiation was assessed by immunohistochemistry, alcian-blue staining, qRT-PCR, and quantification of alkaline phosphatase (ALP) activity. Pre-differentiated pellets were transplanted subcutaneously into SCID mice to investigate stable cartilage formation. Transforming growth factor (TGF)-beta was always required for chondrogenic differentiation and deposition of a collagen-type-II-positive extracellular matrix, while bone morphogenetic protein (BMP)-2, -4, -6, -7, aFGF, and IGF-I (10 ng/ml) were alone not sufficiently inductive. Each of these factors allowed differentiation in combination with TGF-beta, however, without preventing collagen type X expression. bFGF or parathyroid hormone-like peptide (PTHrP) inhibited the TGF-beta-responsive COL2A1 and COL10A1 expression and ALP induction when added from day 0 or 21. In line with a reversible ALP inhibition, in vivo calcification of pellets was not prevented. Late up-regulation of PTH1R mRNA suggests that early PTHrP effects may be mediated by a receptor-independent pathway. While TGF-beta was a full inducer, bFGF and PTHrP were potent inhibitors for early and late chondrogenesis, seemed to induce a shift from matrix anabolism to catabolism, but did not selectively suppress COL10A1 expression. Within a developmental window of collagen type II(+)/collagen type X(-) cells, bFGF and PTHrP may allow inhibition of further differentiation toward hypertrophy to obtain stable chondrocytes for transplantation purposes.


Assuntos
Diferenciação Celular , Condrócitos/metabolismo , Condrogênese , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Células-Tronco Mesenquimais/metabolismo , Proteína Relacionada ao Hormônio Paratireóideo/metabolismo , Fragmentos de Peptídeos/metabolismo , Azul Alciano , Fosfatase Alcalina/metabolismo , Animais , Biomarcadores/metabolismo , Proteínas Morfogenéticas Ósseas/metabolismo , Forma Celular , Células Cultivadas , Condrócitos/patologia , Condrócitos/transplante , Colágeno Tipo II/genética , Colágeno Tipo X/genética , Corantes , Fator 1 de Crescimento de Fibroblastos/metabolismo , Humanos , Hipertrofia , Imuno-Histoquímica , Fator de Crescimento Insulin-Like I/metabolismo , Metaloproteinase 13 da Matriz/genética , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/patologia , Camundongos , Camundongos SCID , Fenótipo , RNA Mensageiro/metabolismo , Receptor Tipo 1 de Hormônio Paratireóideo/genética , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Coloração e Rotulagem/métodos , Fatores de Tempo , Fator de Crescimento Transformador beta/metabolismo
6.
J Pathol ; 216(2): 158-66, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18702172

RESUMO

Phenotypic and molecular parallels between the development of chondrosarcoma and the differentiation of chondrocytes in normal growth plate suggest that chondrosarcoma may arise from mesenchymal precursor cells driven towards chondrogenesis. We hypothesized that a comparison between cartilaginous tumours and their possible physiological cells of origin, mesenchymal stem cells (MSCs), might have biological and clinical relevance. MSCs from eight donors were submitted to chondrogenic differentiation in spheroid cultures. Expression profiles of MSCs at days 0, 7, 14, 28 and 42 of chondrogenesis and of 18 chondrosarcomas with different histological grades were studied using a customized cDNA array. Hierarchical clustering of MSC gene expression during chondrogenesis allowed the classification of samples in a pre-chondrogenic and a chondrogenic cluster corresponding to the phenotypes of early and late differentiation stages. The 74 genes differentially expressed between the two clusters were defined as chondrogenesis-relevant genes. Gene expression profiles of chondrosarcoma were submitted to hierarchical clustering on the basis of these chondrogenesis-relevant genes. This analysis allowed clear distinction between grade I and grade III chondrosarcoma and separated grade II chondrosarcoma into two groups. All grade II chondrosarcomas with occurrence of metastasis were found together with the grade III chondrosarcomas in the pre-chondrogenic cluster. This analysis shows that a molecular approach based on the comparison of tumour samples to an in vitro model for chondrogenic differentiation allows a new classification of chondrosarcoma in two clusters. These data suggest that the identification of a pre-chondrogenic and a chondrogenic phenotype for chondrosarcoma by gene expression profiling could develop into a useful tool to predict the clinical behaviour of chondrosarcoma.


Assuntos
Condrogênese/genética , Condrossarcoma/genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Células-Tronco Mesenquimais/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Diferenciação Celular , Linhagem Celular Tumoral , Análise por Conglomerados , Feminino , Expressão Gênica , Marcadores Genéticos , Humanos , Masculino , Análise em Microsséries , Pessoa de Meia-Idade
7.
Osteoarthritis Cartilage ; 16(1): 48-60, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17604188

RESUMO

OBJECTIVE: Mesenchymal stem cells (MSCs) are a population of cells broadly discussed to support cartilage repair. The differentiation of MSCs into articular chondrocytes is, however, still poorly understood on the molecular level. The aim of this study was to perform an almost genome-wide screen for genes differentially expressed between cartilage and MSCs and to extract new markers useful to define chondrocyte differentiation stages. METHODS: Gene expression profiles of MSCs (n=8) and articular cartilage from OA patients (n=7) were compared on a 30,000 cDNA-fragment array and differentially expressed genes were extracted by subtraction. Expression of selected genes was assessed during in vitro chondrogenic differentiation of MSCs and during dedifferentiation of expanded chondrocytes using quantitative and semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Protein secretion was measured by enzyme-linked immunosorbent assay. RESULTS: Eighty-seven genes were differentially expressed between MSCs and cartilage with a more than three-fold difference. Sixty-seven of them were higher expressed in cartilage and among them 15 genes were previously not detected in cartilage. Differential expression was confirmed for 69% of 26 reanalysed genes by RT-PCR. The profiles of three unknown transcripts and six protease-related molecules were characterised during differentiation. SERPINA1 and SERPINA3 mRNA expression correlated with chondrogenic differentiation of MSCs and dedifferentiation of chondrocytes, and SERPINA1 protein levels in culture supernatants could be correlated alike. CONCLUSIONS: cDNA-array analysis identified SERPINA1 and A3 as new differentiation-relevant genes for cartilage. Since SERPINA1 secretion correlated with both chondrogenesis of MSCs and dedifferentiation during chondrocyte expansion, it represents an attractive marker for refinement of chondrocyte differentiation.


Assuntos
Cartilagem Articular/citologia , Condrócitos/citologia , Condrogênese , Perfilação da Expressão Gênica , Células-Tronco Mesenquimais/citologia , Osteoartrite/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos de Diferenciação/genética , Cartilagem Articular/metabolismo , Diferenciação Celular , Condrócitos/metabolismo , Ensaio de Imunoadsorção Enzimática , Humanos , Células-Tronco Mesenquimais/metabolismo , Análise em Microsséries , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Osteoartrite/metabolismo , Osteoartrite/patologia , RNA Mensageiro/análise , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Serpinas/genética , Serpinas/metabolismo , alfa 1-Antitripsina/genética , alfa 1-Antitripsina/metabolismo
9.
Z Kardiol ; 94(10): 684-9, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16200484

RESUMO

A 65-year old patient was admitted after having sustained a ventricular septum rupture 18 days after an anterior myocardial infarction. He developed acute heart failure. Given the extremely high perioperative risk in surgical approaches in this setting, we decided for a transcatheter closure of the defect with an exclusively venous approach. After a complete recovery, the patient underwent open heart surgery with aorto coronary bypass, aneurysmectomy, and removal of the closure device. This case demonstrates that transcatheter closure of a post infarction ventricular septum rupture is a technically feasible and suitable method.


Assuntos
Cateterismo Cardíaco/métodos , Procedimentos Cirúrgicos Cardiovasculares/métodos , Septos Cardíacos/lesões , Septos Cardíacos/cirurgia , Ventrículos do Coração/lesões , Ventrículos do Coração/cirurgia , Infarto do Miocárdio/cirurgia , Idoso , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/cirurgia , Humanos , Masculino , Infarto do Miocárdio/complicações , Ruptura/diagnóstico , Ruptura/etiologia , Ruptura/cirurgia
10.
J Neural Transm (Vienna) ; 111(1): 27-35, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14714213

RESUMO

Mice deficient in the serotonin transporter (5HTT) display highly elevated extracellular 5HT levels. 5HT exerts ist effects via at least fourteen different cloned 5HT receptors located pre- and postsynaptically. In contrast to the other 5HT receptors, the 5HT3 receptor is a ionotropic receptor with ligand-gated cation channel function. Since G-protein-coupled 5HT receptors show extensive adaptive changes in 5HTT-deficient mice, we investigated whether 5HT3 receptors are also altered in these mice. Using quantitative autoradiography, we found that 5HT3 receptors are upregulated in frontal cortex (+46%), parietal cortex (+42%), and in stratum oriens of the CA3 region of the hippocampus (+18%) of 5HTT knockout mice. Changes in 5HT3 receptor mRNA expression, as determined by quantitative in situ hybridisation, were less pronounced. The adaptive changes of 5HT3 receptor expression constitute a part of the complex regulatory pattern of 5HT receptors in 5HTT knockout mice.


Assuntos
Glicoproteínas de Membrana/deficiência , Proteínas de Membrana Transportadoras , Proteínas do Tecido Nervoso , Prosencéfalo/metabolismo , Receptores 5-HT3 de Serotonina/biossíntese , Animais , Proteínas de Transporte/genética , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ligação Proteica/fisiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores 5-HT3 de Serotonina/genética , Proteínas da Membrana Plasmática de Transporte de Serotonina
11.
J Psychosom Res ; 50(3): 155-60, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11316508

RESUMO

OBJECTIVES: The practice of homeopathy rests on symptoms, which have been produced by medicinal substances in healthy volunteers, often applied at ultramolecular dilutions. It is unknown whether these symptom patterns are due to specific effects or chance fluctuation. METHODS: We tested the hypothesis that a homeopathic substance can bring about symptoms different from observation and placebo in a double-blind, placebo-controlled crossover design with baseline observation. RESULTS: 87 out of 118 healthy volunteers took both placebo and homeopathic belladonna 30CH in random sequence, after a 2-week observation period, and finished the 8-week trial. Apart from an insignificant tendency for subjects to report more symptoms with belladonna (mean number: 27.34), as compared to observation (24.26) or placebo (24.17), there was no indication that subjects reacted differently to homeopathy than to placebo or during baseline. CONCLUSION: There is no indication that belladonna 30CH produces symptoms different from placebo or from no intervention. Symptoms of a homeopathic pathogenetic trial (HPT) are most likely chance fluctuations.


Assuntos
Atropa belladonna/uso terapêutico , Homeopatia/normas , Materia Medica/farmacologia , Fitoterapia , Plantas Medicinais , Plantas Tóxicas , Adulto , Estudos Cross-Over , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Resultado do Tratamento
12.
Mol Psychiatry ; 6(3): 350-2, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11326308

RESUMO

Idiopathic Parkinson's disease (PD) is a common neurodegenerative disorder with prominent motor symptoms. However, depression is common in PD, affecting about 40% of PD patients. Since there is extensive evidence of degeneration of serotonin (5HT) neurons and loss of the 5HT transporter (5HTT) in PD, we assessed whether a functional polymorphism in the promoter of the 5HTT gene (5HTT gene-linked polymorphic region, 5HTTLPR), which determines high or low 5HT uptake, is associated with depressive symptomatology in PD patients. We found that patients with the short allele of the 5HTTLPR had significantly higher scores on the Hamilton Depression Scale. A functional promoter polymorphism of the monoamine oxidase A (MAOA) gene showed no association. Thus, the 5HTTLPR but not the MAOA gene promoter-associated polymorphism may be a risk factor for depression in PD patients, while neither polymorphism increases the risk for development of Parkinson's disease itself.


Assuntos
Proteínas de Transporte/genética , Depressão/genética , Variação Genética , Glicoproteínas de Membrana/genética , Proteínas de Membrana Transportadoras , Proteínas do Tecido Nervoso , Doença de Parkinson/genética , Alelos , Feminino , Expressão Gênica , Humanos , Masculino , Monoaminoxidase/genética , Doença de Parkinson/psicologia , Polimorfismo Genético , Regiões Promotoras Genéticas/genética , Proteínas da Membrana Plasmática de Transporte de Serotonina
13.
Eur Neuropsychopharmacol ; 10(6): 489-93, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11115739

RESUMO

The serotonin (5HT) transporter (5HTT) removes 5HT from the synaptic cleft and is thus critical to the control of serotonergic neurotransmission. Mice with a targeted inactivation of the 5HTT represent a novel and unique tool to study serotonergic system functioning. Because the release of 5HT is regulated by adenosine, we investigated 5HTT-deficient mice for possible adaptive changes of adenosine A(1) and A(2A) receptors. A(1) and A(2A) receptors were studied by means of quantitative autoradiography using the radioligands [3H]8-cyclopentyl-1,3-dipropylxanthine and [3H]CGS 21680, respectively. A comparison of 5HTT knockout versus control mice revealed upregulation of A(1) receptors in the dorsal raphe nucleus (DRN, +21%), but not in any of the serotonergic projection areas, and downregulation of A(2A) receptors in basal ganglia. The adaptive changes of A(1) and A(2A) receptors in 5HTT-deficient mice are likely to represent a compensatory neuroprotective effect mediated by the adenosinergic modulatory system. For comparison, these receptors were also studied in monoamine oxidase A (MAOA) knockout mice and in 5HTT/MAOA double knockout mice. 5HTT/MAOA double knockout mice showed adaptive changes of adenosine A(1) and A(2A) receptors similar to 5HTT knockout mice, while investigation of MAOA-deficient mice revealed an upregulation of A(2A) receptors, which may relate to a role of both MAOA and adenosine A(2A) receptors in anxiety.


Assuntos
Proteínas de Transporte/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras , Monoaminoxidase/metabolismo , Proteínas do Tecido Nervoso , Receptores Purinérgicos P1/metabolismo , Animais , Glicoproteínas de Membrana/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Monoaminoxidase/deficiência , Receptor A2A de Adenosina , Proteínas da Membrana Plasmática de Transporte de Serotonina
14.
Opt Lett ; 20(7): 683-5, 1995 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-19859296

RESUMO

A quantitative comparison of the photorefractive effect in annealed proton-exchanged channel waveguides in MgO-doped and congruent LiNbO(3) at the wavelengths of 633 and 830 nm is presented. An accurate measurement technique is described to measure the refractive-index change as a function of time and the guided mode intensity for different wavelengths. The results show that doping with 7% MgO reduces the photorefractive effect at a wavelength of lambda = 633 nm by 2 orders of magnitude. The photorefractive effect in the doped substrate shows only a weak dependence on the guided power. Doping with 4 mol.% MgO has only little effect on the photorefractive effect compared with that on the congruent material. A reduced photovoltaic current is responsible for the small photorefractive effect in the 7 mol. %-doped substrate.

16.
Implant Dent ; 2(1): 11-7, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8358372

RESUMO

The transmandibular implant system is designed for the reconstruction and rehabilitation of the endentulous mandible utilizing an extraoral approach. Transmandibular implants were placed in 19 patients and mandibular bony changes were followed using standardized panoramic radiography. Eleven sites were identified on each postoperative radiograph and the percentage of radiographic enlargement was calculated for each site. The true bony changes were then computed for both short-term (9.4 months) and long-term (53.4 months) follow-up. Patients with an average mandibular height in the saddle areas of 3.5 to 8.9 mm showed bilateral bony regeneration in the saddle areas and over the most distal cortical screws of the implants. Most of these bony changes were seen in the first year, but continued beyond that time. Patients with residual bone height of 9.0 to 12.9 mm had little bone change, while patients with bone height of 13.0 to 20.5 mm demonstrated slight resorption. Theories for the observed changes are presented. The transmandibular implant is especially indicated for the severely atrophic mandible because its position within the mandible and the rigid box frame design of the implant promote bilateral bone regeneration distal to the framework of the implant.


Assuntos
Perda do Osso Alveolar/fisiopatologia , Regeneração Óssea , Implantação Dentária Endóssea/métodos , Arcada Edêntula/cirurgia , Doenças Mandibulares/fisiopatologia , Idoso , Perda do Osso Alveolar/cirurgia , Análise de Variância , Remodelação Óssea , Análise do Estresse Dentário , Feminino , Seguimentos , Humanos , Masculino , Doenças Mandibulares/reabilitação , Pessoa de Meia-Idade
17.
Stomatol DDR ; 40(3): 134-6, 1990 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-2284660

RESUMO

The informatics team of the Stomatological Society of the GDR provides a complete list of presently available program packages for home, 8 and 16-bit computers and a list of the programming teams. Main developments for the use of PC's in stomatology are described as well. By establishing clear lines for the development of software, standardized user software can be guaranteed.


Assuntos
Instrumentos Odontológicos , Microcomputadores , Software , Alemanha , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...