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1.
Phys Sportsmed ; 51(2): 129-138, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-34808064

RESUMO

METHODS: Fifty-four male athletes from two different teams were involved. Accidents and injuries were recorded immediately after the incident by a team physician present at every race. Exposure, location, type and cause of injury have been recorded. Incidence was calculated. Severity was measured as a cumulative severity score and burden depicted in a risk matrix. RESULTS: Total time of exposure was 12537 hours over 3524 athlete days and 544002 kilometers of racing. 98 accidents were recorded, with 83 leading to injury. The total number of recorded injuries was 193. Injury incidence for all injuries was 54,8 (±SD 47,7-62,8) /1000 athlete days, 15,4 (±SD 13,4-17,7) /1000 athlete hours and 35,5 (±SD 30,8-40,8) /100.000 km raced. By far the most frequent types of injury were hematomas, contusions and bruising (n = 141, 73%) followed by lacerations (n = 22; 11,4%). Most injuries affected the arm and elbow (n = 34, 17,6%) followed by the shoulder and clavicle (n = 28, 14,5%) and occurred with contact (79%). Fractures pose a high injury burden due to long time loss, whereas hematomas, contusions and bruising showed the highest incidence numbers but comparably less time loss. CONCLUSION: Road cyclists' injuries have been underestimated in previous studies. Hematomas, contusions and bruising pose the highest number of injuries with a broad degree of severity and range of injury burden. Fractures are less common but show the highest injury burden. The upper extremities are involved the most.


Assuntos
Traumatismos em Atletas , Contusões , Fraturas Ósseas , Humanos , Masculino , Traumatismos em Atletas/epidemiologia , Estudos Prospectivos , Incidência , Estações do Ano , Contusões/epidemiologia , Fraturas Ósseas/epidemiologia
2.
Sportverletz Sportschaden ; 35(3): 147-153, 2021 08.
Artigo em Alemão | MEDLINE | ID: mdl-34225378

RESUMO

INTRODUCTION: Regional and league-specific differences in injury risk and time loss have been observed in professional European football. Besides time of play or different pre-season preparations, possible reasons may also include medical and sport-scientific support. A survey of what UEFA deems to be the best four football clubs has therefore been conducted to investigate the personnel status in the fields of medicine, physiotherapy, massage, sports science and athletic and "strength and conditioning" coaching in order to compare the Erste Bundesliga with the first leagues of the other countries. METHODS: The study is based on a survey of all 78 teams in the highest football leagues of Germany (Bundesliga), Spain (La Liga), Italy (Serie A) and England (Premier League). The teams were contacted directly and a questionnaire concerning their personnel deployment in the different fields was handed out. RESULTS: The Bundesliga was found to have a significantly lower total number of employees compared with the other European leagues (6.9 vs. 11.02; p < 0.0001). The number of physicians in the Bundesliga is significantly higher (2.2 vs. 1.76; p = 0.0259), but the number of physicians dedicating more than 80 % of their total medical practice to the team was significantly lower in the Bundesliga (0.2 vs. 1.45; < 0.0001). In the group of physiotherapists (1.8 vs. 3.6; p < 0.001), massage therapists (2.1 vs. 2.69; p = 0.0094), sports scientists (0.3 vs. 1.12; p < 0.0001) and athletic and "strength and conditioning" coaches (0.5 vs. 1.83; p < 0.0001), there were also significant differences between the staff structure in the Bundesliga compared with the grouped results of the other leagues. CONCLUSION: The personnel structure and the personnel employment in the Bundesliga in sports medicine and sports sciences differs significantly from La Liga, Serie A and the Premier League with the latter three leagues having more personnel and the personnel having closer ties to their teams. Further investigation is necessary to find out if this may be a reason for the differences in injury rates observed between these leagues. A special focus should be placed on country-specific differences in the professions including education and scope of work.


Assuntos
Futebol , Medicina Esportiva , Humanos , Alemanha , Modalidades de Fisioterapia
3.
J Fungi (Basel) ; 6(4)2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-33027904

RESUMO

Chronic recalcitrant dermatophytoses, due to Trichophyton (T.) mentagrophytes Type VIII are on the rise in India and are noteworthy for their predominance. It would not be wrong to assume that travel and migration would be responsible for the spread of T. mentagrophytes Type VIII from India, with many strains resistant to terbinafine, to other parts of the world. From September 2016 until March 2020, a total of 29 strains of T. mentagrophytes Type VIII (India) were isolated. All patients were residents of Germany: 12 females, 15 males and the gender of the remaining two was not assignable. Patients originated from India (11), Pakistan (two), Bangladesh (one), Iraq (two), Bahrain (one), Libya (one) and other unspecified countries (10). At least two patients were German-born residents. Most samples (21) were collected in 2019 and 2020. All 29 T. mentagrophytes isolates were sequenced (internal transcribed spacer (ITS) and translation elongation factor 1-α gene (TEF1-α)). All were identified as genotype VIII (India) of T. mentagrophytes. In vitro resistance testing revealed 13/29 strains (45%) to be terbinafine-resistant with minimum inhibitory concentration (MIC) breakpoints ≥0.2 µg/mL. The remaining 16 strains (55%) were terbinafine-sensitive. Point mutation analysis revealed that 10/13 resistant strains exhibited Phe397Leu amino acid substitution of squalene epoxidase (SQLE), indicative for in vitro resistance to terbinafine. Two resistant strains showed combined Phe397Leu and Ala448Thr amino acid substitutions, and one strain a single Leu393Phe amino acid substitution. Out of 16 terbinafine-sensitive strains, in eight Ala448Thr, and in one Ala448Thr +, new Val444 Ile amino acid substitutions were detected. Resistance to both itraconazole and voriconazole was observed in three out of 13 analyzed strains. Treatment included topical ciclopirox olamine plus topical miconazole or sertaconazole. Oral itraconazole 200 mg twice daily for four to eight weeks was found to be adequate. Terbinafine-resistant T. mentagrophytes Type VIII are being increasingly isolated. In Germany, transmission of T. mentagrophytes Type VIII from the Indian subcontinent to Europe should be viewed as a significant public health issue.

4.
Hautarzt ; 71(9): 705-710, 2020 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-32394081

RESUMO

Three boys from the same city, treated by the same dermatologist, developed tinea capitis. Two of them, 4 and 8 years old, underwent mycological diagnostic workup. However, no pathogens familiar in this country, such as Microsporum (M.) canis or Trichophyton (T.) tonsurans, were isolated, but instead that of a dermatophyte that has not been found in Germany for decades. Both dermatophyte isolates showed white-beige-brownish colonies with a flat, radiating edge and a central, verrucous curvature. The sequencing of the internal transcribed spacer (ITS) region of the rDNA confirmed the suspicion of M. ferrugineum already expressed based on the morphological picture. The anthropophilic dermatophyte occurs in the Middle East, Asia, Eastern Europe and Africa and is considered to be the cause of tinea capitis or tinea corporis in children and adolescents. In 2016, M. ferrugineum has again been isolated in Germany, probably as a result of migration movements. The fungus is strikingly isolated to martial arts, especially wrestlers. It mainly affects children and adolescents, some with a Russian-German background. The anthropophilic dermatophyte is transmitted directly from person to person, especially in the case of tinea capitis. An indirect transmission, for example, via mats in martial arts is likely.


Assuntos
Microsporum/isolamento & purificação , Tinha do Couro Cabeludo/diagnóstico , Antifúngicos/uso terapêutico , Arthrodermataceae , Criança , Pré-Escolar , Alemanha , Humanos , Masculino , Microsporum/classificação , Tinha do Couro Cabeludo/tratamento farmacológico , Resultado do Tratamento
5.
Magn Reson Imaging ; 62: 174-180, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30654162

RESUMO

PURPOSE: Artifacts arising from undersampling are not always treatable as incoherent noise for the pattern matching process in Magnetic Resonance Fingerprinting (MRF). To estimate the effect of undersampling artifacts on MRF quantitative results, spiral sampling trajectories and their temporal variation is examined. METHODS: The effect of sampling trajectories and their variation during the MRF experiment was assessed by characterizing aliasing artifacts. Temporal rearrangements of sampling trajectories were tested and evaluated in simulations and scans of phantoms and in a volunteer brain. RESULTS: Results show that some temporal variations of sampling patterns can lead to spatial biases in MRF parameter maps. Observed effects are consistent with derived performance indicators for different interleaving schemes, leading to substantially improved MRF sampling patterns. CONCLUSION: With the help of the presented simulation framework, MRF implementations can be investigated and improved. This was demonstrated for a spiral FISP (Fast imaging with steady-state free precession) MRF implementation, where a significantly improved interleaving scheme was identified, and confirmed by experiment.


Assuntos
Encéfalo/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética , Algoritmos , Artefatos , Mapeamento Encefálico , Calibragem , Simulação por Computador , Humanos , Imagens de Fantasmas
6.
J Magn Reson Imaging ; 47(6): 1562-1571, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29159855

RESUMO

BACKGROUND: The excitation inhomogeneity artifact occurring at 3T in the abdomen can lead to dramatic loss of signal and contrast, thereby hampering diagnosis. PURPOSE: To assess excitation homogeneity and image quality achieved by nonselective prototypical kT -points pulses, compared to tailored static RF shimming, in clinical routine on a commercial dual-transmit scanner. STUDY TYPE: Retrospective study with Institutional Review Board approval; informed consent was waived. POPULATION: Fifty consecutive patients referred for liver MRI at a single hospital. FIELD STRENGTH/SEQUENCE: 3D breath-hold dynamic contrast-enhanced (DCE) MRI at 3T. ASSESSMENT: Flip angle homogeneity was estimated via numerical simulation based on measured static and RF field maps. In all, 20 of the 50 patients underwent DCE-MRI while a pulse designer was present. The effect of RF shimming and kT -point pulses could be compared by repeating the acquisition with each transmit scheme before injection and in the late phase. Signal homogeneity, T1 contrast, enhancement quality, structure details, and global image quality were assessed on a 4-level scale (0 to 3) by two radiologists. STATISTICAL TESTS: Means were compared using Wilcoxon signed-rank tests. RESULTS: Normalized root mean square flip angle error was significantly reduced with kT -points compared to static RF shimming (8.5% ± 1.5% [mean ± standard deviation, SD] vs. 20.4% ± 9.8%; P < 0.0001). The worst case (heavy ascites) led to 13.0% (kT -points) vs. 54.9% (RF shimming). Global image quality was significantly higher for kT -points (2.3 ± 0.5 vs. 1.9 ± 0.6; P = 0.008). One subject's examination was judged unusable with RF shimming by one reader, none with kT -points. 85% of kT -points acquisitions were graded at least 2/3, and only 55% for static RF shimming. DATA CONCLUSION: KT -points reduce excitation inhomogeneity quantitatively and qualitatively, especially in patients with ascites and prone to B1 shading. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1562-1571.


Assuntos
Artefatos , Processamento de Imagem Assistida por Computador/métodos , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética , Radiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Ascite/diagnóstico por imagem , Simulação por Computador , Feminino , Humanos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Pâncreas/diagnóstico por imagem , Reprodutibilidade dos Testes , Estudos Retrospectivos , Processamento de Sinais Assistido por Computador , Adulto Jovem
7.
J Clin Invest ; 125(11): 4223-38, 2015 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-26485286

RESUMO

A high intake of dietary salt (NaCl) has been implicated in the development of hypertension, chronic inflammation, and autoimmune diseases. We have recently shown that salt has a proinflammatory effect and boosts the activation of Th17 cells and the activation of classical, LPS-induced macrophages (M1). Here, we examined how the activation of alternative (M2) macrophages is affected by salt. In stark contrast to Th17 cells and M1 macrophages, high salt blunted the alternative activation of BM-derived mouse macrophages stimulated with IL-4 and IL-13, M(IL-4+IL-13) macrophages. Salt-induced reduction of M(IL-4+IL-13) activation was not associated with increased polarization toward a proinflammatory M1 phenotype. In vitro, high salt decreased the ability of M(IL-4+IL-13) macrophages to suppress effector T cell proliferation. Moreover, mice fed a high salt diet exhibited reduced M2 activation following chitin injection and delayed wound healing compared with control animals. We further identified a high salt-induced reduction in glycolysis and mitochondrial metabolic output, coupled with blunted AKT and mTOR signaling, which indicates a mechanism by which NaCl inhibits full M2 macrophage activation. Collectively, this study provides evidence that high salt reduces noninflammatory innate immune cell activation and may thus lead to an overall imbalance in immune homeostasis.


Assuntos
Interleucina-13/farmacologia , Interleucina-4/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Cloreto de Sódio na Dieta/toxicidade , Cloreto de Sódio/farmacologia , Animais , Células da Medula Óssea/efeitos dos fármacos , Células Cultivadas , Quitina/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Código das Histonas/efeitos dos fármacos , Imunidade Inata/efeitos dos fármacos , Inflamação , Macrófagos/classificação , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mitocôndrias/efeitos dos fármacos , Fosforilação Oxidativa/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/fisiologia , Distribuição Aleatória , Transdução de Sinais/efeitos dos fármacos , Cloreto de Sódio na Dieta/farmacologia , Serina-Treonina Quinases TOR/fisiologia , Cicatrização/efeitos dos fármacos
8.
Blood ; 126(4): 504-7, 2015 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-26063165

RESUMO

The (pro)renin receptor (PRR) was originally thought to be important for regulating blood pressure via the renin-angiotensin system. However, it is now emerging that PRR has instead a generic role in cellular development. Here, we have specifically deleted PRR from T cells. T-cell-specific PRR-knockout mice had a significant decrease in thymic cellularity, corresponding with a 100-fold decrease in the number of CD4(+) and CD8(+) thymocytes, and a large increase in double-negative (DN) precursors. Gene expression analysis on sorted DN3 thymocytes indicated that PRR-deficient thymocytes have perturbations in key cellular pathways essential at the DN3 stage, including transcription and translation. Further characterization of DN T-cell progenitors leads us to propose that PRR deletion affects thymocyte survival and development at multiple stages; from DN3 through to DN4, double-positive, and single-positive CD4 and CD8. Our study thus identifies a new role for PRR in T-cell development.


Assuntos
Diferenciação Celular , Receptores de Superfície Celular/fisiologia , Subpopulações de Linfócitos T/citologia , Timócitos/citologia , Animais , Feminino , Citometria de Fluxo , Integrases/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Timócitos/imunologia , Timócitos/metabolismo , Receptor de Pró-Renina
9.
Biol Open ; 4(5): 608-21, 2015 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-25882555

RESUMO

According to the general understanding, the chondrocyte lineage terminates with the elimination of late hypertrophic cells by apoptosis in the growth plate. However, recent cell tracking studies have shown that murine hypertrophic chondrocytes can survive beyond "terminal" differentiation and give rise to a progeny of osteoblasts participating in endochondral bone formation. The question how chondrocytes convert into osteoblasts, however, remained open. Following the cell fate of hypertrophic chondrocytes by genetic lineage tracing using BACCol10;Cre induced YFP-reporter gene expression we show that a progeny of Col10Cre-reporter labelled osteoprogenitor cells and osteoblasts appears in the primary spongiosa and participates - depending on the developmental stage - substantially in trabecular, endosteal, and cortical bone formation. YFP(+) trabecular and endosteal cells isolated by FACS expressed Col1a1, osteocalcin and runx2, thus confirming their osteogenic phenotype. In searching for transitory cells between hypertrophic chondrocytes and trabecular osteoblasts we identified by confocal microscopy a novel, small YFP(+)Osx(+) cell type with mitotic activity in the lower hypertrophic zone at the chondro-osseous junction. When isolated from growth plates by fractional enzymatic digestion, these cells termed CDOP (chondrocyte-derived osteoprogenitor) cells expressed bone typical genes and differentiated into osteoblasts in vitro. We propose the Col10Cre-labeled CDOP cells mark the initiation point of a second pathway giving rise to endochondral osteoblasts, alternative to perichondrium derived osteoprogenitor cells. These findings add to current concepts of chondrocyte-osteocyte lineages and give new insight into the complex cartilage-bone transition process in the growth plate.

10.
Cell Metab ; 21(3): 493-501, 2015 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-25738463

RESUMO

Immune cells regulate a hypertonic microenvironment in the skin; however, the biological advantage of increased skin Na(+) concentrations is unknown. We found that Na(+) accumulated at the site of bacterial skin infections in humans and in mice. We used the protozoan parasite Leishmania major as a model of skin-prone macrophage infection to test the hypothesis that skin-Na(+) storage facilitates antimicrobial host defense. Activation of macrophages in the presence of high NaCl concentrations modified epigenetic markers and enhanced p38 mitogen-activated protein kinase (p38/MAPK)-dependent nuclear factor of activated T cells 5 (NFAT5) activation. This high-salt response resulted in elevated type-2 nitric oxide synthase (Nos2)-dependent NO production and improved Leishmania major control. Finally, we found that increasing Na(+) content in the skin by a high-salt diet boosted activation of macrophages in a Nfat5-dependent manner and promoted cutaneous antimicrobial defense. We suggest that the hypertonic microenvironment could serve as a barrier to infection.


Assuntos
Anti-Infecciosos/farmacologia , Leishmaniose Cutânea/tratamento farmacológico , Leishmaniose Cutânea/metabolismo , Macrófagos/metabolismo , Pele/metabolismo , Sódio/metabolismo , Animais , Ativação Enzimática/fisiologia , Humanos , Leishmania major/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Camundongos , Fatores de Transcrição NFATC/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Pele/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
11.
Magn Reson Med ; 73(3): 1137-50, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24752979

RESUMO

PURPOSE: We compare the performance of eight parallel transmit (pTx) body arrays with up to 32 channels and a standard birdcage design. Excitation uniformity, local specific absorption rate (SAR), global SAR, and power metrics are analyzed in the torso at 3 T for radiofrequency (RF)-shimming and 2-spoke excitations. METHODS: We used a fast cosimulation strategy for field calculation in the presence of coupling between transmit channels. We designed spoke pulses using magnitude least squares optimization with explicit constraint of SAR and power and compared the performance of the different pTx coils using the L-curve method. RESULTS: PTx arrays outperformed the conventional birdcage coil in all metrics except peak and average power efficiency. The presence of coupling exacerbated this power efficiency problem. At constant excitation fidelity, the pTx array with 24 channels arranged in three z-rows could decrease local SAR more than 4-fold (2-fold) for RF-shimming (2-spoke) compared to the birdcage coil for pulses of equal duration. Multi-row pTx coils had a marked performance advantage compared to single row designs, especially for coronal imaging. CONCLUSION: PTx coils can simultaneously improve the excitation uniformity and reduce SAR compared to a birdcage coil when SAR metrics are explicitly constrained in the pulse design.


Assuntos
Imageamento por Ressonância Magnética/instrumentação , Magnetismo/instrumentação , Modelos Biológicos , Absorção de Radiação , Simulação por Computador , Desenho Assistido por Computador , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
12.
Apoptosis ; 19(7): 1080-98, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24722832

RESUMO

Endoplasmic reticulum (ER) stress plays an essential role in unfolded protein response induced apoptosis contributing to several pathological conditions. Glycogen synthase kinase-3ß (GSK-3ß) plays a central role in several apoptotic signaling, including ER stress, as the active form of GSK-3ß induces apoptosis. The phosphorylation of cAMP responsive element (CRE) binding protein (CREB) Ser-133 (S133) residue is the end-point of various signaling pathways, like growth factor signaling, while the Ser-129 (S129) residue is phosphorylated by GSK-3ß. The significance of the ubiquitously expressed transcription factor CREB is demonstrated in prolonged, tunicamycin (TM)-induced ER stress in this study. In the experiments wild-type (wt) CREB, S129Ala, S133Ala or S129Ala-S133Ala mutant CREB expressing PC12 rat pheochromocytoma cell lines showed increased survival under TM-evoked prolonged ER stress compared to wtPC12 cells. After TM treatment ER stress was activated in all PC12 cell types. Lithium and SB-216763, the selective, well-known inhibitors of GSK-3ß, decreased TM-induced apoptosis and promoted cell survival. The proapoptotic BH3-only Bcl-2 family member Bcl-2-interacting mediator of cell death (Bim) level was decreased in the different CREB overexpressing PC12 cells as a result of TM treatment. CREB overexpression also inhibited the sequestration of Bim protein from tubulin molecules, as it was demonstrated in wtPC12 cells. Transient expression of wtCREB diminished TM-induced apoptosis in wtPC12, Rat-1 and primary rat vascular smooth muscle cells. These findings demonstrate a novel role of CREB in different cell types as a potent protector against ER stress.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Estresse do Retículo Endoplasmático , Tunicamicina/farmacologia , Animais , Linhagem Celular , Sobrevivência Celular , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Microtúbulos/metabolismo , Músculo Liso Vascular/citologia , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Mutação , Especificidade de Órgãos , Células PC12 , Ratos
13.
Magn Reson Med ; 71(4): 1446-57, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23776100

RESUMO

PURPOSE: We propose a constrained optimization approach for designing parallel transmit (pTx) pulses satisfying all regulatory and hardware limits. We study the trade-offs between excitation accuracy, local and global specific absorption rate (SAR), and maximum and average power for small flip-angle pTx (eight channels) spokes pulses in the torso at 3 T and in the head at 7 T. METHODS: We compare the trade-offs between the above-mentioned quantities using the L-curve method. We use a primal-dual algorithm and a compressed set of local SAR matrices to design radio-frequency (RF) pulses satisfying all regulatory (including local SAR) and hardware constraints. RESULTS: Local SAR can be substantially reduced (factor of 2 or more) by explicitly constraining it in the pulse design process compared to constraining global SAR or pulse power alone. This often comes at the price of increased pulse power. CONCLUSION: Simultaneous control of power and SAR is needed for the design of pTx pulses that are safe and can be played on the scanner. Constraining a single quantity can create large increase in the others, which can then rise above safety or hardware limits. Simultaneous constraint of local SAR and power is fast enough to be applicable in a clinical setting.


Assuntos
Algoritmos , Encéfalo/anatomia & histologia , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Humanos , Aumento da Imagem/instrumentação , Interpretação de Imagem Assistida por Computador/instrumentação , Imageamento por Ressonância Magnética/instrumentação , Imagens de Fantasmas , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Razão Sinal-Ruído
14.
Bone ; 55(1): 102-12, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23567158

RESUMO

In order to elucidate the role of ß-catenin in hypertrophic cartilage zone of the growth plate, we deleted the ß-catenin gene ctnnb1specifically from hypertrophic chondrocytes by mating ctnnb1(fl/fl) mice with BAC-Col10a1-Cre-deleter mice. Surprisingly, this resulted in a significant reduction of subchondral trabecular bone formation in BACCol10Cre; ctnnb1(Δ/Δ) (referred to as Cat-ko) mice, although Cre expression was restricted to hypertrophic chondrocytes. The size of the Col10a1 positive hypertrophic zone was normal, but qRT-PCR revealed reduced expression of Mmp13, and Vegfa in Cat-ko hypertrophic chondrocytes, indicating impaired terminal differentiation. Immunohistological and in situ hybridization analysis revealed the substantial deficiency of collagen I positive mature osteoblasts, but equal levels of osterix-positive cells in the subchondral bone marrow space of Cat-ko mice, indicating that the supply of osteoblast precursor cells was not reduced. The fact that in Cat-ko mice subchondral trabeculae were lacking including their calcified cartilage core indicated a strongly enhanced osteoclast activity. In fact, TRAP staining as well as in situ hybridization analysis of Mmp9 expression revealed denser occupation of the cartilage erosion zone with enlarged osteoclasts as compared to the control growth plate, suggesting increased RANKL or reduced osteoprotegerin (Opg) activity in this zone. This notion was confirmed by qRT-PCR analysis of mRNA extracted from cultured hypertrophic chondrocytes or from whole epiphyses, showing increased Rankl mRNA levels in Cat-ko as compared to control chondrocytes, whereas changes in OPG levels were not significant. These results indicate that ß-catenin levels in hypertrophic chondrocytes play a key role in regulating osteoclast activity and trabecular bone formation at the cartilage-bone interface by controlling RANKL expression in hypertrophic chondrocytes.


Assuntos
Condrócitos/metabolismo , Condrócitos/patologia , Deleção de Genes , Lâmina de Crescimento/metabolismo , Lâmina de Crescimento/patologia , Osteogênese , beta Catenina/genética , Azul Alciano/metabolismo , Animais , Cartilagem/metabolismo , Cartilagem/patologia , Diferenciação Celular , Linhagem Celular , Separação Celular , Colágeno Tipo I/metabolismo , Imunofluorescência , Hipertrofia , Imuno-Histoquímica , Hibridização In Situ , Camundongos , Camundongos Knockout , Osteoclastos/metabolismo , Osteoclastos/patologia , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , beta Catenina/metabolismo
15.
Magn Reson Med ; 67(6): 1566-78, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22083594

RESUMO

The management of local and global power deposition in human subjects (specific absorption rate, SAR) is a fundamental constraint to the application of parallel transmission (pTx) systems. Even though the pTx and single channel have to meet the same SAR requirements, the complex behavior of the spatial distribution of local SAR for transmission arrays poses problems that are not encountered in conventional single-channel systems and places additional requirements on pTx radio frequency pulse design. We propose a pTx pulse design method which builds on recent work to capture the spatial distribution of local SAR in numerical tissue models in a compressed parameterization in order to incorporate local SAR constraints within computation times that accommodate pTx pulse design during an in vivo magnetic resonance imaging scan. Additionally, the algorithm yields a protocol-specific ultimate peak in local SAR, which is shown to bound the achievable peak local SAR for a given excitation profile fidelity. The performance of the approach was demonstrated using a numerical human head model and a 7 Tesla eight-channel transmit array. The method reduced peak local 10 g SAR by 14-66% for slice-selective pTx excitations and 2D selective pTx excitations compared to a pTx pulse design constrained only by global SAR. The primary tradeoff incurred for reducing peak local SAR was an increase in global SAR, up to 34% for the evaluated examples, which is favorable in cases where local SAR constraints dominate the pulse applications.


Assuntos
Algoritmos , Aumento da Imagem/instrumentação , Aumento da Imagem/métodos , Imageamento por Ressonância Magnética/instrumentação , Imageamento por Ressonância Magnética/métodos , Processamento de Sinais Assistido por Computador/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
Magn Reson Med ; 66(5): 1468-76, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21604294

RESUMO

The supervision of local specific absorption rate (SAR) in parallel transmission applications in MRI is crucial. One existing approach is to use electromagnetic simulations including human anatomical models and to precalculate the electric field distributions of each individual channel. These can be superposed later with respect to certain combined excitations under investigation, and the local SAR distribution can be evaluated. Local SAR maxima can be obtained by exhaustive search over all investigated subvolumes of the body model. Practical challenges arise for the adequate handling and comparing of precalculated field distributions as long as the expected combined radiofrequency excitations are still undetermined. Worst-case approximations for local SAR lead to significant radiofrequency pulse performance limitations. Optimizing local SAR in radiofrequency pulse design using constraints for each subvolume is impractical. A method is proposed to significantly reduce the complexity without restriction to particular radiofrequency excitations. By constructing several matrices, it becomes sufficient to consider only these so-called Virtual Observation Points for an adequate, conservative estimation of the maximum local SAR. The applied techniques involve concepts of vector optimization as well as semidefinite programming.


Assuntos
Imageamento por Ressonância Magnética/métodos , Absorção , Algoritmos , Fenômenos Eletromagnéticos , Humanos , Matemática , Modelos Anatômicos
17.
Clin Cancer Res ; 17(13): 4367-77, 2011 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-21562037

RESUMO

PURPOSE: Constitutive Wnt signaling caused by mutations in the ß-catenin gene is a molecular hallmark of adamantinomatous craniopharyngiomas (adaCP) and promotes infiltration into adjacent brain tissue. Herein, we studied the pathogenic role of epidermal growth factor receptor (EGFR) activation in adaCP and whether tumor cell migration can be inhibited by the tyrosine kinase inhibitor gefitinib. EXPERIMENTAL DESIGN: EGFR expression and activation [phosphorylated EGFR (EGFR-P)] was examined in a cohort of 25 surgical adaCP samples by PCR and Western blotting. Regional and cellular localization patterns of EGFR-P, ß-catenin, and its target gene product Fascin were determined by immunofluorescence microscopy. Mutation analysis and gene copy number assay were carried out to examine genetic alterations in the EGFR gene. The impact of EGFR signaling on tumor cell migration was studied in vitro by using 11 primary human adaCP cultures treated with the EGFR ligand EGF and its inhibitor gefitinib. RESULTS: Neither mutations nor amplifications in the EGFR gene were detected in our adaCP series. However, EGFR-P was detectable in tumor cell clusters located at the brain infiltration border and colocalized with nuclear ß-catenin and Fascin. Activated EGFR significantly promoted tumor cell migration in vitro, whereas gefitinib reduced both tumor cell motility and Fascin expression. CONCLUSION: Our data suggest EGFR signaling to play a role in cell migration and brain infiltration of adaCP. Targeting the EGFR signaling pathway by gefitinib may present a promising pharmacologic option in the treatment of this challenging tumor disease.


Assuntos
Craniofaringioma/genética , Craniofaringioma/patologia , Receptores ErbB/genética , Receptores ErbB/metabolismo , Transdução de Sinais/genética , Adolescente , Adulto , Idoso , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Células Cultivadas , Criança , Pré-Escolar , Variações do Número de Cópias de DNA/genética , Feminino , Humanos , Masculino , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/metabolismo , Pessoa de Meia-Idade , Mutação/genética , Fosforilação , Adulto Jovem , beta Catenina/genética
18.
Curr Eye Res ; 35(4): 267-73, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20373892

RESUMO

PURPOSE: To determine whether the epithelium of the human nasolacrimal ducts contains aquaporins (AQPs), a family of membrane proteins that function as selective pores and are able to transport water, glycerol, and other small solutes across the cell plasma membrane. METHODS: Expression of AQPs 0 and 1-10 in human nasolacrimal duct tissue was determined by reverse transcription polymerase chain reaction (RT-PCR). Positive PCR amplification products were verified by direct cDNA sequencing. Western blot analysis was used to detect AQPs 3-5. Antisera specific for AQPs were used in immunohistochemical analysis to determine the presence and distribution of ten AQPs (AQP 0 and 1-9) in epithelia and subepithelial glands of the nasolacrimal ducts. All samples investigated originated from human postmortem tissue. RESULTS: In human nasolacrimal duct samples, AQPs 1, 3, 4, 5, 7, 8, 9, and 10 were identified by RT-PCR. No RT-PCR products were detected for AQPs 0, 2, and 6. All AQPs, which were detected by RT-PCR, were also confirmed by direct sequencing of the cDNA. Immunohistochemical analyses revealed AQPs 1, 3, 5, 7, 8, and 9 in human nasolacrimal duct epithelium and were detected in different cells. Expression of AQP 4 could not be detected immunohistochemically but by Western blot analysis. Protein detection of AQP 10 could not be performed due to the unavailability of an appropriate antibody. CONCLUSIONS: The results suggest specific roles for AQPs in water transport through the epithelium of the nasolacrimal ducts and underline the presumption that tear fluid components are selectively absorbed in the nasolacrimal passage.


Assuntos
Aquaporinas/genética , Regulação da Expressão Gênica/fisiologia , Ducto Nasolacrimal/metabolismo , Idoso , Idoso de 80 Anos ou mais , Western Blotting , Células Cultivadas , Epitélio/metabolismo , Feminino , Perfilação da Expressão Gênica , Humanos , Técnicas Imunoenzimáticas , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA
19.
Int J Pharm ; 330(1-2): 23-31, 2007 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-16997520

RESUMO

The effect of various surfactants (sodium cholate, sodium taurocholate, Tween 80 and Poloxamer F68) on enhancing the transepithelial permeability of fexofenadine.HCl was evaluated in a human nasal epithelial cell monolayer model. The cytotoxicity of the surfactants on the human nasal epithelial cells was evaluated by the MTT assay. A dose-dependent reduction of cell viability was observed at higher than critical micelle concentration (CMC) of the surfactants, and the IC50 of non-ionic surfactants (Tween 80 and Poloxamer F68) was higher than that of ionic surfactants (sodium cholate and sodium taurocholate). The TEER values significantly decreased after 2 h incubation with the ionic surfactants, but were recovered after 24 h in the fresh culture media. Ionic surfactants significantly increased the transepithelial permeability (P(app)) of fexofenadine.HCl compared to the non-ionic surfactants. The reduction of TEER values upon exposing the cell monolayer to the surfactants for 2 h correlated well with the P(app) of fexofenadine.HCl, which suggests that the permeation-enhancing mechanism of the ionic surfactants is by altering the tight junction property of the paracellular pathway. F-actin staining showed that the effect of ionic surfactants on the tight junction is temporary and reversible, which is consistent with the TEER value recovery within 24 h. These results imply that ionic surfactants are potentially useful permeation enhancers for nasal delivery of hydrophilic compounds, such as fexofenadine.HCl. This study also indicated the usefulness of the human nasal epithelial cell monolayer model not only for evaluating the in vitro nasal drug transport but also for studying the mechanism and toxicity of enhancers.


Assuntos
Antagonistas não Sedativos dos Receptores H1 da Histamina/farmacocinética , Mucosa Nasal/efeitos dos fármacos , Mucosa Nasal/metabolismo , Tensoativos/farmacologia , Terfenadina/análogos & derivados , Permeabilidade da Membrana Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Formazans , Antagonistas não Sedativos dos Receptores H1 da Histamina/farmacologia , Humanos , Microscopia Confocal , Poloxâmero/farmacologia , Polissorbatos , Colato de Sódio/farmacologia , Ácido Taurocólico/farmacologia , Terfenadina/farmacocinética , Terfenadina/farmacologia , Sais de Tetrazólio
20.
Ophthalmology ; 112(6): 1023-30, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15885787

RESUMO

OBJECTIVE: To study the distribution of isoforms of vascular endothelial growth factor (VEGF) and its receptors VEGFR1 and VEGFR2 in pterygia and to compare it with that in healthy conjunctivas. DESIGN: Nonrandomized comparative (cadaver controlled) study with histopathologic correlations. METHODS: Tissue specimens from 75 patients treated for primary pterygia were analyzed using immunohistochemical studies as well as different molecular biological examinations. Healthy conjunctivas from 33 patients treated for cataracts as well as specimens from the conjunctiva, limbus, and lens of both eyes of 12 body donors served as controls. TESTING: Surgical specimens of pterygia and normal conjunctiva specimens were processed with paraffin, sectioned, stained using specific antibodies against VEGF and its receptors, and examined by light microscopy. The other part of both groups of specimens as well as specimens from body donors were prepared and analyzed by means of reverse-transcription polymerase chain reaction (RT-PCR), real-time RT-PCR, enzyme-linked immunosorbent assay, and Western blots. MAIN OUTCOME PARAMETERS: Vascular endothelial growth factor and VEGFR1 and VEGFR2 were analyzed to indentify the splice variants of VEGF as well as the distribution and amount of VEGF and both receptors in pterygia and the control tissues. RESULTS: In analysis of specimens from pterygium patients as well as normal conjunctivas, VEGF121 and VEGF165 were identified as the only VEGF splice forms expressed. In addition to VEGF, VEGFR1 and VEGFR2 were detected in pterygia and conjunctivas and immunostained within the epithelium of pterygia and conjunctivas and on intrapterygial and intraconjunctival endothelial cells. Levels of VEGFR1 and VEGFR2 mRNA were lower in pterygia than in conjunctivas but similar in limbal and pterygium samples. Vascular endothelial growth factor levels were higher in pterygia than in conjunctivas, but were similar in the limbus and pterygia. CONCLUSIONS: The results reveal similar behaviors in limbal and pterygium epithelial cells in terms of VEGF and VEGFR expression, with the presumption that pterygia arise from limbal epithelial cells and that human conjunctivas are not a suitable control for the analysis of pterygia. Moreover, the results suggest that VEGF might play an active role in the physiology of conjunctival epithelial cells.


Assuntos
Limbo da Córnea/metabolismo , Pterígio/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Western Blotting , Túnica Conjuntiva/metabolismo , Ensaio de Imunoadsorção Enzimática , Células Epiteliais/metabolismo , Feminino , Regulação da Expressão Gênica , Humanos , Técnicas Imunoenzimáticas , Cristalino/metabolismo , Masculino , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator A de Crescimento do Endotélio Vascular/genética , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética
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